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Sample records for halophilic gram-positive bacterium

  1. Sediminibacillus massiliensis sp. nov., a moderately halophilic, Gram-positive bacterium isolated from a stool sample of a young Senegalese man.

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    Senghor, Bruno; Bassène, Hubert; Khelaifia, Saber; Robert, Catherine; Fournier, Pierre-Edouard; Ruimy, Raymond; Sokhna, Cheikh; Raoult, Didier; Lagier, Jean-Christophe

    2018-07-01

    A Gram-positive, moderately halophilic bacterium, referred to as strain Marseille-P3518 T , was isolated from a stool sample with 2% NaCl concentration from a healthy 15-year-old male living in Dielmo, a village in Senegal. Cells are aerobic, rod-shaped and motile and display endospore formation. Strain Marseille-P3518 T can grow in a medium with 0-20% (w/v) sodium chloride (optimally at 5-7.5% w/v). The major fatty acids were 12-methyl-tetradecanoic acid (45.8%), 13-methyl-tetradecanoic acid (26.9%) and 12-methyl-tridecanoic acid (12.8%). The genome is 4,347,479 bp long with 42.1% G+C content. It contains 4282 protein-coding and 107 RNA genes. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that strain Marseille-P3518 T is a member of the Bacillaceae family and is closely related to Sediminibacillus albus (97.4% gene sequence similarity). Strain Marseille-P3518 T was clearly differentiated from its phylogenetic neighbors on the basis of phenotypic and genotypic features. Strain Marseille-P3518 T is, therefore, considered to be a novel representative of the genus Sediminibacillus, for which the name Sediminibacillus massiliensis sp. nov. is proposed, and the type strain is Marseille-P3518 T (CSUR P3518T, DSM69894).

  2. Microbial culturomics to isolate halophilic bacteria from table salt: genome sequence and description of the moderately halophilic bacterium Bacillus salis sp. nov.

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    E.H. Seck

    2018-05-01

    Full Text Available Bacillus salis strain ES3T (= CSUR P1478 = DSM 100598 is the type strain of B. salis sp. nov. It is an aerobic, Gram-positive, moderately halophilic, motile and spore-forming bacterium. It was isolated from commercial table salt as part of a broad culturomics study aiming to maximize the culture conditions for the in-depth exploration of halophilic bacteria in salty food. Here we describe the phenotypic characteristics of this isolate, its complete genome sequence and annotation, together with a comparison with closely related bacteria. Phylogenetic analysis based on 16S rRNA gene sequences indicated 97.5% similarity with Bacillus aquimaris, the closest species. The 8 329 771 bp long genome (one chromosome, no plasmids exhibits a G+C content of 39.19%. It is composed of 18 scaffolds with 29 contigs. Of the 8303 predicted genes, 8109 were protein-coding genes and 194 were RNAs. A total of 5778 genes (71.25% were assigned a putative function. Keywords: Bacillus salis, culturomics, genome, halophilic bacteria, human gut, taxonogenomics

  3. High quality draft genome sequence of the moderately halophilic bacterium Pontibacillus yanchengensis Y32(T) and comparison among Pontibacillus genomes.

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    Huang, Jing; Qiao, Zi Xu; Tang, Jing Wei; Wang, Gejiao

    2015-01-01

    Pontibacillus yanchengensis Y32(T) is an aerobic, motile, Gram-positive, endospore-forming, and moderately halophilic bacterium isolated from a salt field. In this study, we describe the features of P. yanchengensis strain Y32(T) together with a comparison with other four Pontibacillus genomes. The 4,281,464 bp high-quality-draft genome of strain Y32(T) is arranged into 153 contigs containing 3,965 protein-coding genes and 77 RNA encoding genes. The genome of strain Y32(T) possesses many genes related to its halophilic character, flagellar assembly and chemotaxis to support its survival in a salt-rich environment.

  4. Microbial culturomics to isolate halophilic bacteria from table salt: genome sequence and description of the moderately halophilic bacterium Bacillus salis sp. nov.

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    Seck, E H; Diop, A; Armstrong, N; Delerce, J; Fournier, P-E; Raoult, D; Khelaifia, S

    2018-05-01

    Bacillus salis strain ES3 T (= CSUR P1478 = DSM 100598) is the type strain of B. salis sp. nov. It is an aerobic, Gram-positive, moderately halophilic, motile and spore-forming bacterium. It was isolated from commercial table salt as part of a broad culturomics study aiming to maximize the culture conditions for the in-depth exploration of halophilic bacteria in salty food. Here we describe the phenotypic characteristics of this isolate, its complete genome sequence and annotation, together with a comparison with closely related bacteria. Phylogenetic analysis based on 16S rRNA gene sequences indicated 97.5% similarity with Bacillus aquimaris, the closest species. The 8 329 771 bp long genome (one chromosome, no plasmids) exhibits a G+C content of 39.19%. It is composed of 18 scaffolds with 29 contigs. Of the 8303 predicted genes, 8109 were protein-coding genes and 194 were RNAs. A total of 5778 genes (71.25%) were assigned a putative function.

  5. A pathway closely related to the (D)-tagatose pathway of gram-negative enterobacteria identified in the gram-positive bacterium Bacillus licheniformis.

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    Van der Heiden, Edwige; Delmarcelle, Michaël; Lebrun, Sarah; Freichels, Régine; Brans, Alain; Vastenavond, Christian M; Galleni, Moreno; Joris, Bernard

    2013-06-01

    We report the first identification of a gene cluster involved in d-tagatose catabolism in Bacillus licheniformis. The pathway is closely related to the d-tagatose pathway of the Gram-negative bacterium Klebsiella oxytoca, in contrast to the d-tagatose 6-phosphate pathway described in the Gram-positive bacterium Staphylococcus aureus.

  6. A Pathway Closely Related to the d-Tagatose Pathway of Gram-Negative Enterobacteria Identified in the Gram-Positive Bacterium Bacillus licheniformis

    OpenAIRE

    Van der Heiden, Edwige; Delmarcelle, Michaël; Lebrun, Sarah; Freichels, Régine; Brans, Alain; Vastenavond, Christian M.; Galleni, Moreno; Joris, Bernard

    2013-01-01

    We report the first identification of a gene cluster involved in d-tagatose catabolism in Bacillus licheniformis. The pathway is closely related to the d-tagatose pathway of the Gram-negative bacterium Klebsiella oxytoca, in contrast to the d-tagatose 6-phosphate pathway described in the Gram-positive bacterium Staphylococcus aureus.

  7. A Pathway Closely Related to the d-Tagatose Pathway of Gram-Negative Enterobacteria Identified in the Gram-Positive Bacterium Bacillus licheniformis

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    Van der Heiden, Edwige; Lebrun, Sarah; Freichels, Régine; Brans, Alain; Vastenavond, Christian M.; Galleni, Moreno; Joris, Bernard

    2013-01-01

    We report the first identification of a gene cluster involved in d-tagatose catabolism in Bacillus licheniformis. The pathway is closely related to the d-tagatose pathway of the Gram-negative bacterium Klebsiella oxytoca, in contrast to the d-tagatose 6-phosphate pathway described in the Gram-positive bacterium Staphylococcus aureus. PMID:23524682

  8. Noncontiguous finished genome sequence and description of Planococcus massiliensis sp. nov., a moderately halophilic bacterium isolated from the human gut

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    E.H. Seck

    2016-03-01

    Full Text Available We propose the main phenotypic characteristics and the complete genome sequence and annotation of Planococcus massiliensis strain ES2T (= CSUR P1103 = DSM 28915, the type strain of P. massiliensis sp. nov., isolated from a faeces sample collected from a healthy Senegalese man. It is an aerobic, Gram-positive, moderately halophilic, motile and rod-shaped bacterium. The 3 357 017 bp long genome exhibits a G+C content of 46.0% and contains 3357 protein-coding genes and 48 RNA genes.

  9. Halomonas indalinina sp.nov., a moderately halophilic bacterium isolated from a solar saltern in Cabo de Gata, Al,eria, southern Spain

    NARCIS (Netherlands)

    Cabrera, A.; Aguilera, M.; Fuentes Enriquez de Salamanca, S.; Incerti, C.; Russell, N.J.; Ramos-Cormenzana, A.; Monteoliva-Sanchez, M.

    2007-01-01

    moderately halophilic bacterium, strain CG2.1T, isolated from a solar saltern at Cabo de Gata, a wildlife reserve located in the province of Almería, southern Spain, was subjected to a polyphasic taxonomic study. This organism was an aerobic, motile, Gram-negative rod that produced orange-pigmented

  10. Chloride and organic osmolytes: a hybrid strategy to cope with elevated salinities by the moderately halophilic, chloride-dependent bacterium Halobacillus halophilus.

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    Saum, Stephan H; Pfeiffer, Friedhelm; Palm, Peter; Rampp, Markus; Schuster, Stephan C; Müller, Volker; Oesterhelt, Dieter

    2013-05-01

    Salt acclimation in moderately halophilic bacteria is the result of action of a grand interplay orchestrated by signals perceived from the environment. To elucidate the cellular players involved in sensing and responding to changing salinities we have determined the genome sequence of Halobacillus halophilus, a Gram-positive moderate halophilic bacterium that has a strict requirement for the anion chloride. Halobacillus halophilus synthesizes a multitude of different compatible solutes and switches its osmolyte strategy with the external salinity and growth phase. Based on the emerging genome sequence, the compatible solutes glutamate, glutamine, proline and ectoine have already been experimentally studied. The biosynthetic routes for acetyl ornithine and acetyl lysine are also delineated from the genome sequence. Halobacillus halophilus is nutritionally very versatile and most compatible solutes cannot only be produced but also used as carbon and energy sources. The genome sequence unravelled isogenes for many pathways indicating a fine regulation of metabolism. Halobacillus halophilus is unique in integrating the concept of compatible solutes with the second fundamental principle to cope with salt stress, the accumulation of molar concentrations of salt (Cl(-)) in the cytoplasm. Extremely halophilic bacteria/archaea, which exclusively rely on the salt-in strategy, have a high percentage of acidic proteins compared with non-halophiles with a low percentage. Halobacillus halophilus has an intermediate position which is consistent with its ability to integrate both principles. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  11. Proteomic characterization of the outer membrane vesicle of the halophilic marine bacterium Novosphingobium pentaromativorans US6-1.

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    Yun, Sung Ho; Lee, Sang-Yeop; Choi, Chi-Won; Lee, Hayoung; Ro, Hyun-Joo; Jun, Sangmi; Kwon, Yong Min; Kwon, Kae Kyoung; Kim, Sang-Jin; Kim, Gun-Hwa; Kim, Seung Il

    2017-01-01

    Novosphingobium pentaromativorans US6-1 is a Gram-negative halophilic marine bacterium able to utilize several polycyclic aromatic hydrocarbons such as phenanthrene, pyrene, and benzo[a]pyrene. In this study, using transmission electron microscopy, we confirmed that N. pentaromativorans US6-1 produces outer membrane vesicles (OMVs). N. pentaromativorans OMVs (hereafter OMV Novo ) are spherical in shape, and the average diameter of OMV Novo is 25-70 nm. Proteomic analysis revealed that outer membrane proteins and periplasmic proteins of N. pentaromativorans are the major protein components of OMV Novo . Comparative proteomic analysis with the membrane-associated protein fraction and correlation analysis demonstrated that the outer membrane proteins of OMV Novo originated from the membrane- associated protein fraction. To the best of our knowledge, this study is the first to characterize OMV purified from halophilic marine bacteria.

  12. Complete genome of Martelella sp. AD-3, a moderately halophilic polycyclic aromatic hydrocarbons-degrading bacterium.

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    Cui, Changzheng; Li, Zhijie; Qian, Jiangchao; Shi, Jie; Huang, Ling; Tang, Hongzhi; Chen, Xin; Lin, Kuangfei; Xu, Ping; Liu, Yongdi

    2016-05-10

    Martelella sp. strain AD-3, a moderate halophilic bacterium, was isolated from a petroleum-contaminated soil with high salinity in China. Here, we report the complete genome of strain AD-3, which contains one circular chromosome and two circular plasmids. An array of genes related to metabolism of polycyclic aromatic hydrocarbons and halophilic mechanism in this bacterium was identified by the whole genome analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. An extreme-halophile archaebacterium possesses the interlock type of prephenate dehydratase characteristic of the Gram-positive eubacteria

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    Jensen, R. A.; d'Amato, T. A.; Hochstein, L. I.

    1988-01-01

    The focal point of phenylalanine biosynthesis is a dehydratase reaction which in different organisms may be prephenate dehydratase, arogenate dehydratase, or cyclohexadienyl dehydratase. Gram-positive, Gram-negative, and cyanobacterial divisions of the eubacterial kingdom exhibit different dehydratase patterns. A new extreme-halophile isolate, which grows on defined medium and is tentatively designated as Halobacterium vallismortis CH-1, possesses the interlock type of prephenate dehydratase present in Gram-positive bacteria. In addition to the conventional sensitivity to feedback inhibition by L-phenylalanine, the phenomenon of metabolic interlock was exemplified by the sensitivity of prephenate dehydratase to allosteric effects produced by extra-pathway (remote) effectors. Thus, L-tryptophan inhibited activity while L-tyrosine, L-methionine, L-leucine and L-isoleucine activated the enzyme. L-Isoleucine and L-phenylalanine were effective at micromolar levels; other effectors operated at mM levels. A regulatory mutant selected for resistance to growth inhibition caused by beta-2-thienylalanine possessed an altered prephenate dehydratase in which a phenomenon of disproportionately low activity at low enzyme concentration was abolished. Inhibition by L-tryptophan was also lost, and activation by allosteric activators was diminished. Not only was sensitivity to feedback inhibition by L-phenylalanine lost, but the mutant enzyme was now activated by this amino acid (a mutation type previously observed in Bacillus subtilis). It remains to be seen whether this type of prephenate dehydratase will prove to be characteristic of all archaebacteria or of some archaebacterial subgroup cluster.

  14. Salirhabdus euzebyi gen. nov., sp. nov., a Gram-positive, halotolerant bacterium isolated from a sea salt evaporation pond.

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    Albuquerque, Luciana; Tiago, Igor; Rainey, Fred A; Taborda, Marco; Nobre, M Fernanda; Veríssimo, António; da Costa, Milton S

    2007-07-01

    A low-G+C, Gram-positive bacterium, designated CVS-14(T), was recovered from a sea salt evaporation pond on the island of Sal in the Cape Verde Archipelago. This organism was catalase- and oxidase-positive. Cells were motile, spore-forming aerobic rods, with an optimum growth temperature of about 35-40 degrees C and optimum pH between 7.0 and 8.5. Optimal growth occurred in media containing 4-6 % (w/v) NaCl, although the organism was able to grow in medium without added NaCl and in medium containing 16 % NaCl. The cell-wall peptidoglycan was of A1 gamma type and the major respiratory quinone was menaquinone 7 (MK-7). Major fatty acids were iso-15 : 0, anteiso-15 : 0, iso-17 : 0 and anteiso-17 : 0. The DNA G+C content was 37.0 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain CVS-14(T) formed a distinct new branch within the radiation of the moderately halophilic bacilli group, forming a separate lineage from species of the genera Salinibacillus, Paucisalibacillus, Oceanobacillus, Lentibacillus and Virgibacillus. Strain CVS-14(T) showed 16S rRNA gene pairwise similarity values of approximately 95 % with species of the genus Salinibacillus. On the basis of morphological, physiological, chemotaxonomic and phylogenetic characteristics, strain CVS-14(T) is considered to represent a novel species in a new genus, for which the name Salirhabdus euzebyi gen. nov., sp. nov. is proposed. The type strain is CVS-14(T) (=LMG 22839(T)=CIP 108577(T)).

  15. Methods for targetted mutagenesis in gram-positive bacteria

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    Yang, Yunfeng

    2014-05-27

    The present invention provides a method of targeted mutagenesis in Gram-positive bacteria. In particular, the present invention provides a method that effectively integrates a suicide integrative vector into a target gene in the chromosome of a Gram-positive bacterium, resulting in inactivation of the target gene.

  16. Extracellular polymer substance synthesized by a halophilic bacterium Chromohalobacter canadensis 28.

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    Radchenkova, Nadja; Boyadzhieva, Ivanka; Atanasova, Nikolina; Poli, Annarita; Finore, Ilaria; Di Donato, Paola; Nicolaus, Barbara; Panchev, Ivan; Kuncheva, Margarita; Kambourova, Margarita

    2018-04-03

    Halophilic microorganisms are producers of a lot of new compounds whose properties suggest promising perspectives for their biotechnological exploration. Moderate halophilic bacterium Chromohalobacter canadensis 28 was isolated from Pomorie salterns as an extracellular polymer substance (EP) producer. The best carbon source for extracellular polymer production was found to be lactose, a sugar received as a by-product from the dairy industry. After optimization of the culture medium and physicochemical conditions for cultivation, polymer biosynthesis increased more than 2-fold. The highest level of extracellular polymer synthesis by C. canadensis 28 was observed in an unusually high NaCl concentration (15% w/v). Chemical analysis of the purified polymer revealed the presence of an exopolysaccharide (EPS) fraction (14.3% w/w) and protein fraction (72% w/w). HPLC analysis of the protein fraction showed the main presence of polyglutamic acid (PGA) (75.7% w/w). EPS fraction analysis revealed the following sugar composition (% w/w): glucosamine 36.7, glucose 32.3, rhamnose 25.4, xylose 1.7, and not identified sugar 3.9. The hydrogel formed by PGA and EPS fractions showed high swelling behavior, very good emulsifying and stabilizing properties, and good foaming ability. This is the first report for halophilic bacterium able to synthesize a polymer containing PGA fraction. The synthesized biopolymer shows an extremely high hydrophilicity, due to the simultaneous presence of PGA and EPS. The analysis of its functional properties and the presence of glucosamine in the highest proportion in EPS fraction clearly determine the potential of EP synthesized by C. canadensis 28 for application in the cosmetics industry.

  17. Purification and Characterization of Haloalkaline, Organic Solvent Stable Xylanase from Newly Isolated Halophilic Bacterium-OKH

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    Sanghvi, Gaurav; Jivrajani, Mehul; Patel, Nirav; Jivrajani, Heta; Bhaskara, Govinal Badiger; Patel, Shivani

    2014-01-01

    A novel, alkali-tolerant halophilic bacterium-OKH with an ability to produce extracellular halophilic, alkali-tolerant, organic solvent stable, and moderately thermostable xylanase was isolated from salt salterns of Mithapur region, Gujarat, India. Identification of the bacterium was done based upon biochemical tests and 16S rRNA sequence. Maximum xylanase production was achieved at pH 9.0 and 37°C temperature in the medium containing 15% NaCl and 1% (w/v) corn cobs. Sugarcane bagasse and wheat straw also induce xylanase production when used as carbon source. The enzyme was active over a range of 0–25% sodium chloride examined in culture broth. The optimum xylanase activity was observed at 5% sodium chloride. Xylanase was purified with 25.81%-fold purification and 17.1% yield. Kinetic properties such as Km and Vmax were 4.2 mg/mL and 0.31 μmol/min/mL, respectively. The enzyme was stable at pH 6.0 and 50°C with 60% activity after 8 hours of incubation. Enzyme activity was enhanced by Ca2+, Mn2+, and Mg2+ but strongly inhibited by heavy metals such as Hg2+, Fe3+, Ni2+, and Zn2+. Xylanase was found to be stable in organic solvents like glutaraldehyde and isopropanol. The purified enzyme hydrolysed lignocellulosic substrates. Xylanase, purified from the halophilic bacterium-OKH, has potential biotechnological applications. PMID:27350996

  18. Gracilibacillus aidingensis sp. nov., a novel moderately halophilic bacterium isolated from Aiding salt lake.

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    Guan, Tong-Wei; Tian, Lei; Li, En-Yuan; Tang, Shu-Kun; Zhang, Xiao-Ping

    2017-11-01

    A novel Gram-positive, aerobe, moderately halophilic bacterium was isolated from saline soil of Aiding lake in Xinjiang, north-west of China, designated strain YIM 98001 T . Cells were rod-shaped, motile and grew at 5-20% (w/v) NaCl (optimum 10%), pH 6-10 (optimum pH 7.0) and 4-45 °C (optimum 37 °C). The major cellular fatty acids were anteiso C 15:0 , anteiso C 17:0 , iso C 15:0 . The predominant respiratory quinone was MK-7. Diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid were the major polar lipids. Meso-diaminopimelic acid was the diagnostic diamino acid of the cell-wall peptidoglycan. The G+C content was 36.46 mol%. 16S rRNA gene sequence analysis showed that the strain belongs to the family Bacillaceae, with the highest sequence similarity to the type strain Gracilibacillus thailandensis TP2-8 T (96.84%), followed by Gracilibacillus saliphilus YIM 91119 T (96.78%) and Gracilibacillus ureilyticus MF38 T (96.57%), thus confirming the affiliation of strain YIM 98001 T to the genus Gracilibacillus. The polyphasic approach indicates that strain YIM 98001 T represents a novel species of the genus Gracilibacillus, for which the name Gracilibacillus aidingensis is proposed. The type strain is YIM 98001 T (=KCTC 42683 T  = DSMZ 104330 T ).

  19. Marinobacter nitratireducens sp. nov., a halophilic and lipolytic bacterium isolated from coastal surface sea water

    Digital Repository Service at National Institute of Oceanography (India)

    Bhumika, V.; Ravinder, K.; Korpole, S.; Srinivas, T.N.R.; AnilKumar, P.

    A novel Gram-stain-negative, rod-shaped, motile bacterium, designated strain AK21T , was isolated from coastal surface sea water at Visakhapatnam, India. The strain was positive for oxidase, catalase, lipase, L-proline arylamidase...

  20. Probing interaction of Gram-positive and Gram-negative bacterial cells with ZnO nanorods

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    Jain, Aanchal; Bhargava, Richa; Poddar, Pankaj, E-mail: p.poddar@ncl.res.in

    2013-04-01

    In the present work, the physiological effects of the ZnO nanorods on the Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Aerobacter aerogenes) bacterial cells have been studied. The analysis of bacterial growth curves for various concentrations of ZnO nanorods indicates that Gram positive and Gram negative bacterial cells show inhibition at concentrations of ∼ 64 and ∼ 256 μg/mL respectively. The marked difference in susceptibility towards nanorods was also validated by spread plate and disk diffusion methods. In addition, the scanning electron micrographs show a clear damage to the cells via changed morphology of the cells from rod to coccoid etc. The confocal optical microscopy images of these cells also demonstrate the reduction in live cell count in the presence of ZnO nanorods. These, results clearly indicate that the antibacterial activity of ZnO nanorods is higher towards Gram positive bacterium than Gram negative bacterium which indicates that the structure of the cell wall might play a major role in the interaction with nanostructured materials and shows high sensitivity to the particle concentration. Highlights: ► Effect of ZnO nanorods on the growth cycles of four bacterial strains. ► A relation has been established between growth rate of bacteria and concentration. ► Serious damage in the morphology of bacterial cells in the presence of ZnO nanorods. ► Microscopic studies to see the time dependent effect on bacterial cells.

  1. Genome analysis of the Anerobic Thermohalophilic bacterium Halothermothrix orenii

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    Mavromatis, Konstantinos; Ivanova, Natalia; Anderson, Iain; Lykidis, Athanasios; Hooper, Sean D.; Sun, Hui; Kunin, Victor; Lapidus, Alla; Hugenholtz, Philip; Patel, Bharat; Kyrpides, Nikos C.

    2008-11-03

    Halothermothirx orenii is a strictly anaerobic thermohalophilic bacterium isolated from sediment of a Tunisian salt lake. It belongs to the order Halanaerobiales in the phylum Firmicutes. The complete sequence revealed that the genome consists of one circular chromosome of 2578146 bps encoding 2451 predicted genes. This is the first genome sequence of an organism belonging to the Haloanaerobiales. Features of both Gram positive and Gram negative bacteria were identified with the presence of both a sporulating mechanism typical of Firmicutes and a characteristic Gram negative lipopolysaccharide being the most prominent. Protein sequence analyses and metabolic reconstruction reveal a unique combination of strategies for thermophilic and halophilic adaptation. H. orenii can serve as a model organism for the study of the evolution of the Gram negative phenotype as well as the adaptation under thermohalophilic conditions and the development of biotechnological applications under conditions that require high temperatures and high salt concentrations.

  2. Virgibacillus ainsalahensis sp. nov., a Moderately Halophilic Bacterium Isolated from Sediment of a Saline Lake in South of Algeria.

    Science.gov (United States)

    Amziane, Meriam; Darenfed-Bouanane, Amel; Abderrahmani, Ahmed; Selama, Okba; Jouadi, Lydia; Cayol, Jean-Luc; Nateche, Farida; Fardeau, Marie-Laure

    2017-02-01

    A Gram-positive, moderately halophilic, endospore-forming bacterium, designated MerV T , was isolated from a sediment sample of a saline lake located in Ain Salah, south of Algeria. The cells were rod shaped and motile. Isolate MerV T grew at salinity interval of 0.5-25% NaCl (optimum, 5-10%), pH 6.0-12.0 (optimum, 8.0), and temperature between 10 and 40 °C (optimum, 30 °C).The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, a glycolipid, a phospholipid, and two lipids, and MK-7 is the predominant menaquinone. The predominant cellular fatty acids were anteiso C 15:0 and anteiso C 17:0 . The DNA G+C content was 45.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain MerV T was most closely related to Virgibacillus halodenitrificans (gene sequence similarity of 97.0%). On the basis of phenotypic, chemotaxonomic properties, and phylogenetic analyses, strain MerV T (=DSM = 28944 T ) should be placed in the genus Virgibacillus as a novel species, for which the name Virgibacillus ainsalahensis is proposed.

  3. Lentibacillus amyloliquefaciens sp. nov., a halophilic bacterium isolated from saline sediment sample.

    Science.gov (United States)

    Wang, Jing-Li; Ma, Ke-Dong; Wang, Yan-Wei; Wang, Hui-Min; Li, Yan-Bin; Zhou, Shan; Chen, Xiao-Rong; Kong, De-Long; Guo, Xiang; He, Ming-Xiong; Ruan, Zhi-Yong

    2016-02-01

    A Gram-stain positive, non-motile, non-sporogenous, aerobic, rod-shaped and halophilic bacterium, designated LAM0015(T), was isolated from a saline sediment sample collected from Yantai City in China. The isolate was found to be able to grow at NaCl concentrations of 5-25 % (w/v) (optimum: 7-12 %), 15-45 °C (optimum: 35 °C) and pH 5.0-9.0 (optimum: 7.0). The major fatty acids were determined to be anteiso-C15:0 and anteiso-C17:0. The predominant respiratory quinone was identified as MK-7. The cell wall peptidoglycan was determined to contain meso-diaminopimelic acid. The polar lipids were found to be diphosphatidyglycerol, phosphatidylglycerol, five phospholipids and one glycolipid. The DNA G+C content was 43.1 mol% as determined by the T m method. Analysis of the 16S rRNA gene sequence indicated that the isolate belongs within the genus Lentibacillus and is closely related to Lentibacillus persicus DSM 22530(T), Lentibacillus salicampi JCM 11462(T) and Lentibacillus jeotgali JCM 15795(T) with 97.3, 96.7 and 96.4 % sequence similarity, respectively. The DNA-DNA hybridization value between LAM0015(T) and L. persicus DSM 22530(T) was 51.2 ± 1.4 %. Based on its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0015(T) is concluded to represent a novel species of the genus Lentibacillus, for which the name Lentibacillus amyloliquefaciens sp. nov. is proposed. The type strain is LAM0015(T) (=ACCC 06401(T) = JCM 19838(T)).

  4. Genome analysis of the anaerobic thermohalophilic bacterium Halothermothrix orenii.

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    Konstantinos Mavromatis

    Full Text Available Halothermothirx orenii is a strictly anaerobic thermohalophilic bacterium isolated from sediment of a Tunisian salt lake. It belongs to the order Halanaerobiales in the phylum Firmicutes. The complete sequence revealed that the genome consists of one circular chromosome of 2578146 bps encoding 2451 predicted genes. This is the first genome sequence of an organism belonging to the Haloanaerobiales. Features of both Gram positive and Gram negative bacteria were identified with the presence of both a sporulating mechanism typical of Firmicutes and a characteristic Gram negative lipopolysaccharide being the most prominent. Protein sequence analyses and metabolic reconstruction reveal a unique combination of strategies for thermophilic and halophilic adaptation. H. orenii can serve as a model organism for the study of the evolution of the Gram negative phenotype as well as the adaptation under thermohalophilic conditions and the development of biotechnological applications under conditions that require high temperatures and high salt concentrations.

  5. Osmoregulation in the Halophilic Bacterium Halomonas elongata: A Case Study for Integrative Systems Biology.

    Science.gov (United States)

    Kindzierski, Viktoria; Raschke, Silvia; Knabe, Nicole; Siedler, Frank; Scheffer, Beatrix; Pflüger-Grau, Katharina; Pfeiffer, Friedhelm; Oesterhelt, Dieter; Marin-Sanguino, Alberto; Kunte, Hans-Jörg

    2017-01-01

    Halophilic bacteria use a variety of osmoregulatory methods, such as the accumulation of one or more compatible solutes. The wide diversity of compounds that can act as compatible solute complicates the task of understanding the different strategies that halophilic bacteria use to cope with salt. This is specially challenging when attempting to go beyond the pathway that produces a certain compatible solute towards an understanding of how the metabolic network as a whole addresses the problem. Metabolic reconstruction based on genomic data together with Flux Balance Analysis (FBA) is a promising tool to gain insight into this problem. However, as more of these reconstructions become available, it becomes clear that processes predicted by genome annotation may not reflect the processes that are active in vivo. As a case in point, E. coli is unable to grow aerobically on citrate in spite of having all the necessary genes to do it. It has also been shown that the realization of this genetic potential into an actual capability to metabolize citrate is an extremely unlikely event under normal evolutionary conditions. Moreover, many marine bacteria seem to have the same pathways to metabolize glucose but each species uses a different one. In this work, a metabolic network inferred from genomic annotation of the halophilic bacterium Halomonas elongata and proteomic profiling experiments are used as a starting point to motivate targeted experiments in order to find out some of the defining features of the osmoregulatory strategies of this bacterium. This new information is then used to refine the network in order to describe the actual capabilities of H. elongata, rather than its genetic potential.

  6. Isolation, cloning and characterization of an azoreductase from the halophilic bacterium Halomonas elongata.

    Science.gov (United States)

    Eslami, Maryam; Amoozegar, Mohammad Ali; Asad, Sedigheh

    2016-04-01

    Azo dyes are a major class of colorants used in various industries including textile, paper and food. These dyes are regarded as pollutant since they are not readily reduced under aerobic conditions. Halomonas elongata, a halophilic bacterium, has the ability to decolorize different mono and di-azo dyes in anoxic conditions. In this study the putative azoreductase gene of H. elongata, formerly annotated as acp, was isolated, heterologously expressed in Escherichia coli, purified and characterized. The gene product, AzoH, was found to have a molecular mass of 22 kDa. The enzyme requires NADH, as an electron donor for its activity. The apparent Km was 63 μM for NADH and 12 μM for methyl red as a mono-azo dye substrate. The specific activity for methyl red was 0.27 μmol min(-1)mg(-1). The optimum enzyme activity was achieved in 50mM sodium phosphate buffer at pH 6. Although increased salinity resulted in reduced activity, AzoH could decolorize azo dye at NaCl concentrations up to 15% (w/v). The enzyme was also shown to be able to decolorize remazol black B as a representative of di-azo dyes. This is the first report describing the sequence and activity of an azo-reducing enzyme from a halophilic bacterium. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Jeotgalibacillus soli sp. nov., a Gram-stain-positive bacterium isolated from soil.

    Science.gov (United States)

    Cunha, Sofia; Tiago, Igor; Paiva, Gabriel; Nobre, Fernanda; da Costa, Milton S; Veríssimo, António

    2012-03-01

    A Gram-staining-positive, motile, rod-shaped, spore-forming bacterium, designated P9(T), was isolated from soil in Portugal. This organism was aerobic and catalase- and oxidase-positive. It had an optimum growth temperature of about 35 °C and an optimum growth pH of about 8.0-8.5, and grew in medium with 0-9% (w/v) NaCl. The cell-wall peptidoglycan was of the A1α type, with L-lysine as the diagnostic diamino acid. The major respiratory quinone was menaquinone 7 (MK-7) and the major fatty acids were anteiso-C(15:0) (45.4%), iso-C(15:0) (22.0%) and anteiso-C(17:0) (11.2%). The genomic DNA G+C content was about 39.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain P9(T) was most closely related to Jeotgalibacillus campisalis DSM 18983(T) (96.8%) and Jeotgalibacillus marinus DSM 1297(T) (96.5%). These two recognized species formed a coherent cluster with strain P9(T) that was supported by a bootstrap value of 99%. On the basis of the phylogenetic analysis and physiological and biochemical characteristics, strain P9(T) (=DSM 23228(T)=LMG 25523(T)) represents a novel species of the genus Jeotgalibacillus, for which the name Jeotgalibacillus soli sp. nov. is proposed.

  8. Structural characteristics of alkaline phosphatase from the moderately halophilic bacterium Halomonas sp. 593

    International Nuclear Information System (INIS)

    Arai, Shigeki; Yonezawa, Yasushi; Ishibashi, Matsujiro; Matsumoto, Fumiko; Adachi, Motoyasu; Tamada, Taro; Tokunaga, Hiroko; Blaber, Michael; Tokunaga, Masao; Kuroki, Ryota

    2014-01-01

    In order to clarify the structural basis of the halophilic characteristics of an alkaline phosphatase derived from the moderate halophile Halomonas sp. 593 (HaAP), the tertiary structure of HaAP was determined to 2.1 Å resolution by X-ray crystallography. The structural properties of surface negative charge and core hydrophobicity were shown to be intermediate between those characteristic of halophiles and non-halophiles, and may explain the unique functional adaptation to a wide range of salt concentrations. Alkaline phosphatase (AP) from the moderate halophilic bacterium Halomonas sp. 593 (HaAP) catalyzes the hydrolysis of phosphomonoesters over a wide salt-concentration range (1–4 M NaCl). In order to clarify the structural basis of its halophilic characteristics and its wide-range adaptation to salt concentration, the tertiary structure of HaAP was determined by X-ray crystallography to 2.1 Å resolution. The unit cell of HaAP contained one dimer unit corresponding to the biological unit. The monomer structure of HaAP contains a domain comprised of an 11-stranded β-sheet core with 19 surrounding α-helices similar to those of APs from other species, and a unique ‘crown’ domain containing an extended ‘arm’ structure that participates in formation of a hydrophobic cluster at the entrance to the substrate-binding site. The HaAP structure also displays a unique distribution of negatively charged residues and hydrophobic residues in comparison to other known AP structures. AP from Vibrio sp. G15-21 (VAP; a slight halophile) has the highest similarity in sequence (70.0% identity) and structure (C α r.m.s.d. of 0.82 Å for the monomer) to HaAP. The surface of the HaAP dimer is substantially more acidic than that of the VAP dimer (144 exposed Asp/Glu residues versus 114, respectively), and thus may enable the solubility of HaAP under high-salt conditions. Conversely, the monomer unit of HaAP formed a substantially larger hydrophobic interior comprising 329

  9. Structural characteristics of alkaline phosphatase from the moderately halophilic bacterium Halomonas sp. 593

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Shigeki; Yonezawa, Yasushi [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195 (Japan); Ishibashi, Matsujiro [Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065 (Japan); Matsumoto, Fumiko; Adachi, Motoyasu; Tamada, Taro [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195 (Japan); Tokunaga, Hiroko [Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065 (Japan); Blaber, Michael [Florida State University, 1115 West Call Street, Tallahassee, FL 32306-4300 (United States); Tokunaga, Masao [Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065 (Japan); Kuroki, Ryota, E-mail: kuroki.ryota@jaea.go.jp [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195 (Japan)

    2014-03-01

    In order to clarify the structural basis of the halophilic characteristics of an alkaline phosphatase derived from the moderate halophile Halomonas sp. 593 (HaAP), the tertiary structure of HaAP was determined to 2.1 Å resolution by X-ray crystallography. The structural properties of surface negative charge and core hydrophobicity were shown to be intermediate between those characteristic of halophiles and non-halophiles, and may explain the unique functional adaptation to a wide range of salt concentrations. Alkaline phosphatase (AP) from the moderate halophilic bacterium Halomonas sp. 593 (HaAP) catalyzes the hydrolysis of phosphomonoesters over a wide salt-concentration range (1–4 M NaCl). In order to clarify the structural basis of its halophilic characteristics and its wide-range adaptation to salt concentration, the tertiary structure of HaAP was determined by X-ray crystallography to 2.1 Å resolution. The unit cell of HaAP contained one dimer unit corresponding to the biological unit. The monomer structure of HaAP contains a domain comprised of an 11-stranded β-sheet core with 19 surrounding α-helices similar to those of APs from other species, and a unique ‘crown’ domain containing an extended ‘arm’ structure that participates in formation of a hydrophobic cluster at the entrance to the substrate-binding site. The HaAP structure also displays a unique distribution of negatively charged residues and hydrophobic residues in comparison to other known AP structures. AP from Vibrio sp. G15-21 (VAP; a slight halophile) has the highest similarity in sequence (70.0% identity) and structure (C{sup α} r.m.s.d. of 0.82 Å for the monomer) to HaAP. The surface of the HaAP dimer is substantially more acidic than that of the VAP dimer (144 exposed Asp/Glu residues versus 114, respectively), and thus may enable the solubility of HaAP under high-salt conditions. Conversely, the monomer unit of HaAP formed a substantially larger hydrophobic interior

  10. Characterization of a novel chitinase from a moderately halophilic bacterium, Virgibacillus marismortui strain M3-23

    OpenAIRE

    Essghaier, Badiaa; Hedi, Abdeljabbar; Bajji, Mohammed; Jijakli, Haissam; Boudabous, Abdellatif; Sadfi-Zouaoui, Najla

    2012-01-01

    A new chitinase produced by the moderately halophilic bacterium Virgibacillus marismortui strain M3- 23 was identified and characterized. Distinguishable characteristics of high activity and stability at different pH, temperatures and salinity of M3-23 chitinase are reported. Analysis of the catalytic domain sequence from the enzyme highlighted its relationship to glycosyl hydrolase family 18. Comparison of the deduced chitinase sequence from strain M3-23 to known chitinases from Bacillus spe...

  11. c-di-GMP Regulates Various Phenotypes and Insecticidal Activity of Gram-Positive Bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    Yang Fu

    2018-02-01

    Full Text Available C-di-GMP has been well investigated to play significant roles in the physiology of many Gram-negative bacteria. However, its effect on Gram-positive bacteria is less known. In order to more understand the c-di-GMP functions in Gram-positive bacteria, we have carried out a detailed study on the c-di-GMP-metabolizing enzymes and their physiological functions in Bacillus thuringiensis, a Gram-positive entomopathogenic bacterium that has been applied as an insecticide successfully. We performed a systematic study on the ten putative c-di-GMP-synthesizing enzyme diguanylate cyclases (DGCs and c-di-GMP-degrading enzyme phosphodiesterases (PDEs in B. thuringiensis BMB171, and artificially elevated the intracellular c-di-GMP level in BMB171 by deleting one or more pde genes. We found increasing level of intracellular c-di-GMP exhibits similar activities as those in Gram-negative bacteria, including altered activities in cell motility, biofilm formation, and cell-cell aggregation. Unexpectedly, we additionally found a novel function exhibited by the increasing level of c-di-GMP to promote the insecticidal activity of this bacterium against Helicoverpa armigera. Through whole-genome transcriptome profile analyses, we found that 4.3% of the B. thuringiensis genes were differentially transcribed when c-di-GMP level was increased, and 77.3% of such gene products are involved in some regulatory pathways not reported in other bacteria to date. In summary, our study represents the first comprehensive report on the c-di-GMP-metabolizing enzymes, their effects on phenotypes, and the transcriptome mediated by c-di-GMP in an important Gram-positive bacterium.

  12. Extracellular proteases of Halobacillus blutaparonensis strain M9, a new moderately halophilic bacterium.

    Science.gov (United States)

    Santos, Anderson F; Valle, Roberta S; Pacheco, Clarissa A; Alvarez, Vanessa M; Seldin, Lucy; Santos, André L S

    2013-12-01

    Halophilic microorganisms are source of potential hydrolytic enzymes to be used in industrial and/or biotechnological processes. In the present study, we have investigated the ability of the moderately halophilic bacterium Halobacillus blutaparonensis (strain M9), a novel species described by our group, to release proteolytic enzymes. This bacterial strain abundantly proliferated in Luria-Bertani broth supplemented with 2.5% NaCl as well as secreted proteases to the extracellular environment. The production of proteases occurred in bacterial cells grown under different concentration of salt, ranging from 0.5% to 10% NaCl, in a similar way. The proteases secreted by H. blutaparonensis presented the following properties: (i) molecular masses ranging from 30 to 80 kDa, (ii) better hydrolytic activities under neutral-alkaline pH range, (iii) expression modulated according to the culture age, (iv) susceptibility to phenylmethylsulphonyl fluoride, classifying them as serine-type proteases, (v) specific cleavage over the chymotrypsin substrate, and (vi) enzymatic stability in the presence of salt (up to 20% NaCl) and organic solvents (e.g., ether, isooctane and cyclohexane). The proteases described herein are promising for industrial practices due to its haloalkaline properties.

  13. Sporosalibacterium faouarense gen. nov., sp. nov., a moderately halophilic bacterium isolated from oil-contaminated soil.

    Science.gov (United States)

    Rezgui, Raja; Ben Ali Gam, Zouhaier; Ben Hamed, Said; Fardeau, Marie-Laure; Cayol, Jean-Luc; Maaroufi, Abderrazak; Labat, Marc

    2011-01-01

    A novel strictly anaerobic, moderately halophilic and mesophilic bacterium, designated strain SOL3f37(T), was isolated from a hydrocarbon-polluted soil surrounding a deep petroleum environment located in south Tunisia. Cells of strain SOL3f37(T) stained Gram-positive and were motile, straight and spore-forming. Strain SOL3f37(T) had a typical Gram-positive-type cell-wall structure, unlike the thick, multilayered cell wall of its closest relative Clostridiisalibacter paucivorans. The major fatty acids were iso-C(15 : 0) (41 %), iso-C(14 : 0) 3-OH and/or iso-C(15 : 0) dimethyl acetal (21.6 %), iso-C(13 : 0) (4.4 %), anteiso-C(15 : 0) (3.9 %) and iso-C(15 : 1) (2.8 %). Strain SOL3f37(T) grew between 20 and 48 °C (optimum 40 °C) and at pH 6.2-8.1 (optimum pH 6.9). Strain SOL3f37(T) required at least 0.5 NaCl l(-1) and grew in the presence of NaCl concentrations up to 150 g l(-1) (optimum 40 g l(-1)). Yeast extract (2 g l(-1)) was required for degradation of pyruvate, fumarate, fructose, glucose and mannitol. Also, strain SOL3f37(T) grew heterotrophically on yeast extract, peptone and bio-Trypticase, but was unable to grow on Casamino acids. Sulfate, thiosulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content was 30.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SOL3f37(T) was a member of the family Clostridiaceae in the order Clostridiales; strain SOL3f37(T) was related to members of various genera of the family Clostridiaceae. It exhibited highest 16S rRNA gene sequence similarity (93.4 %) with Clostridiisalibacter paucivorans 37HS60(T), 91.8 % with Thermohalobacter berrensis CTT3(T) and 91.7 % with Caloranaerobacter azorensis MV1087(T). On the basis of genotypic, phenotypic and phylogenetic data, it is suggested that strain SOL3f37(T) represents a novel species in a new genus. The name Sporosalibacterium faouarense gen. nov., sp. nov. is

  14. Higher order structure in the 3'-minor domain of small subunit ribosomal RNAs from a gram negative bacterium, a gram positive bacterium and a eukaryote

    DEFF Research Database (Denmark)

    Douthwaite, S; Christensen, A; Garrett, R A

    1983-01-01

    of additional higher order structure in the renatured free RNA. It can be concluded that a high level of conservation of higher order structure has occurred during the evolution of the gram negative and gram positive eubacteria and the eukaryote in both the double helical regions and the "unstructured" regions...

  15. Cloning, Characterization and Analysis of cat and ben Genes from the Phenol Degrading Halophilic Bacterium Halomonas organivorans

    Science.gov (United States)

    Moreno, Maria de Lourdes; Sánchez-Porro, Cristina; Piubeli, Francine; Frias, Luciana; García, María Teresa; Mellado, Encarnación

    2011-01-01

    Background Extensive use of phenolic compounds in industry has resulted in the generation of saline wastewaters that produce significant environmental contamination; however, little information is available on the degradation of phenolic compounds in saline conditions. Halomonas organivorans G-16.1 (CECT 5995T) is a moderately halophilic bacterium that we isolated in a previous work from saline environments of South Spain by enrichment for growth in different pollutants, including phenolic compounds. PCR amplification with degenerate primers revealed the presence of genes encoding ring-cleaving enzymes of the β-ketoadipate pathway for aromatic catabolism in H. organivorans. Findings The gene cluster catRBCA, involved in catechol degradation, was isolated from H. organivorans. The genes catA, catB, catC and the divergently transcribed catR code for catechol 1,2-dioxygenase (1,2-CTD), cis,cis-muconate cycloisomerase, muconolactone delta-isomerase and a LysR-type transcriptional regulator, respectively. The benzoate catabolic genes (benA and benB) are located flanking the cat genes. The expression of cat and ben genes by phenol and benzoic acid was shown by RT-PCR analysis. The induction of catA gene by phenol and benzoic acid was also probed by the measurement of 1,2-CTD activity in H. organivorans growth in presence of these inducers. 16S rRNA and catA gene-based phylogenies were established among different degrading bacteria showing no phylogenetic correlation between both genes. Conclusions/Significance In this work, we isolated and determined the sequence of a gene cluster from a moderately halophilic bacterium encoding ortho-pathway genes involved in the catabolic metabolism of phenol and analyzed the gene organization, constituting the first report characterizing catabolic genes involved in the degradation of phenol in moderate halophiles, providing an ideal model system to investigate the potential use of this group of extremophiles in the decontamination of

  16. Draft genome sequence of Dethiosulfovibrio salsuginis DSM 21565T an anaerobic, slightly halophilic bacterium isolated from a Colombian saline spring.

    Science.gov (United States)

    Díaz-Cárdenas, Carolina; López, Gina; Alzate-Ocampo, José David; González, Laura N; Shapiro, Nicole; Woyke, Tanja; Kyrpides, Nikos C; Restrepo, Silvia; Baena, Sandra

    2017-01-01

    A bacterium belonging to the phylum Synergistetes , genus Dethiosulfovibrio was isolated in 2007 from a saline spring in Colombia. Dethiosulfovibrio salsuginis USBA 82 T ( DSM 21565 T = KCTC 5659 T ) is a mesophilic, strictly anaerobic, slightly halophilic, Gram negative bacterium with a diderm cell envelope. The strain ferments peptides, amino acids and a few organic acids. Here we present the description of the complete genome sequencing and annotation of the type species Dethiosulfovibrio salsuginis USBA 82 T . The genome consisted of 2.68 Mbp with a 53.7% G + C . A total of 2609 genes were predicted and of those, 2543 were protein coding genes and 66 were RNA genes. We detected in USBA 82 T genome six Synergistetes conserved signature indels (CSIs), specific for Jonquetella, Pyramidobacter and Dethiosulfovibrio . The genome of D. salsuginis contained, as expected, genes related to amino acid transport, amino acid metabolism and thiosulfate reduction. These genes represent the major gene groups of Synergistetes , related with their phenotypic traits, and interestingly, 11.8% of the genes in the genome belonged to the amino acid fermentation COG category. In addition, we identified in the genome some ammonification genes such as nitrate reductase genes. The presence of proline operon genes could be related to de novo synthesis of proline to protect the cell in response to high osmolarity. Our bioinformatics workflow included antiSMASH and BAGEL3 which allowed us to identify bacteriocins genes in the genome.

  17. A comparison of liquid-holding recovery and photoreactivation in halophilic and non-halophilic bacteria

    International Nuclear Information System (INIS)

    Fitt, P.S.; Sharma, N.; Castellanos, G.

    1983-01-01

    The ability of the extreme halophile Halobacterium cutirubrum to recover from the effects of ultraviolet radiation during liquid holding in the dark in non-nutrient medium has been compared with that of (i) a moderately halophilic bacterium (NRC 41227) and (ii) Escherichia coli B. The photoreactivabilities of all three bacteria have also been studied. The extreme halophile was incapable of liquid-holding recovery in these conditions, in marked contrast to both E. coli B and the moderate halophile, and also failed to recover when held in nutrient medium in the dark. These results strongly support the hypothesis that H. cutirubrum lacks DNA excision repair. It was also found that ultraviolet-irradiated H. cutirubrum could be almost completely photoreactivated from any level of survival in the range 10 - 4 -80%, provided exposure to visible light was not delayed, whereas the moderate halophile resembled E. coli B and had a comparatively limited capacity for photoreactivation. (Auth.)

  18. The complete genome sequence of the Gram-positive bacterium Bacillus subtilis

    NARCIS (Netherlands)

    Kunst, F; Ogasawara, N; Moszer, [No Value; Albertini, AM; Alloni, G; Azevedo, [No Value; Bertero, MG; Bessieres, P; Bolotin, A; Borchert, S; Borriss, R; Boursier, L; Brans, A; Brignell, SC; Bron, S; Brouillet, S; Bruschi, CV; Caldwell, B; Capuano, [No Value; Carter, NM; Choi, SK; Codani, JJ; Connerton, IF; Cummings, NJ; Daniel, RA; Denizot, F; Devine, KM; Dusterhoft, A; Ehrlich, SD; Emmerson, PT; Entian, KD; Errington, J; Fabret, C; Ferrari, E; Foulger, D; Fujita, M; Fujita, Y; Fuma, S; Galizzi, A; Galleron, N; Ghim, SY; Glaser, P; Goffeau, A; Golightly, EJ; Grandi, G; Guiseppi, G; Guy, BJ; Haga, K; Haiech, J; Harwood, CR; Henaut, A; Hilbert, H; Holsappel, S; Hosono, S; Hullo, MF; Itaya, M; Jones, L; Joris, B; Karamata, D; Kasahara, Y; KlaerrBlanchard, M; Klein, C; Kobayashi, Y; Koetter, P; Koningstein, G; Krogh, S; Kumano, M; Kurita, K; Lapidus, A; Lardinois, S; Lauber, J; Lazarevic, [No Value; Lee, SM; Levine, A; Liu, H; Masuda, S; Mauel, C; Medigue, C; Medina, N; Mellado, RP; Mizuno, M; Moestl, D; Nakai, S; Noback, M; Noone, D; OReilly, M; Ogawa, K; Ogiwara, A; Oudega, B; Park, SH; Parro, [No Value; Pohl, TM; Portetelle, D; Porwollik, S; Prescott, AM; Presecan, E; Pujic, P; Purnelle, B; Rapoport, G; Rey, M; Reynolds, S; Rieger, M; Rivolta, C; Rocha, E; Roche, B; Rose, M; Sadaie, Y; Sato, T; Scanlan, E; Schleich, S; Schroeter, R; Scoffone, F; Sekiguchi, J; Sekowska, A; Seror, SJ; Serror, P; Shin, BS; Soldo, B; Sorokin, A; Tacconi, E; Takagi, T; Takahashi, H; Takemaru, K; Takeuchi, M; Tamakoshi, A; Tanaka, T; Terpstra, P; Tognoni, A; Tosato, [No Value; Uchiyama, S; Vandenbol, M; Vannier, F; Vassarotti, A; Viari, A; Wambutt, R; Wedler, E; Wedler, H; Weitzenegger, T; Winters, P; Wipat, A; Yamamoto, H; Yamane, K; Yasumoto, K; Yata, K; Yoshida, K; Yoshikawa, HF; Zumstein, E; Yoshikawa, H; Danchin, A

    1997-01-01

    Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been

  19. Microbial culturomics unravels the halophilic microbiota repertoire of table salt: description of Gracilibacillus massiliensis sp. nov.

    Directory of Open Access Journals (Sweden)

    Awa Diop

    2016-10-01

    Full Text Available Background: Microbial culturomics represents an ongoing revolution in the characterization of environmental and human microbiome. Methods: By using three media containing high salt concentration (100, 150, and 200 g/L, the halophilic microbial culturome of a commercial table salt was determined. Results: Eighteen species belonging to the Terrabacteria group were isolated including eight moderate halophilic and 10 halotolerant bacteria. Gracilibacillus massiliensis sp. nov., type strain Awa-1T (=CSUR P1441=DSM 29726, is a moderately halophilic gram-positive, non-spore-forming rod, and is motile by using a flagellum. Strain Awa-1T shows catalase activity but no oxidase activity. It is not only an aerobic bacterium but also able to grow in anaerobic and microaerophilic atmospheres. The draft genome of G. massiliensis is 4,207,226 bp long, composed of 13 scaffolds with 36.05% of G+C content. It contains 3,908 genes (3,839 protein-coding and 69 RNA genes. At least 1,983 (52% orthologous proteins were not shared with the closest phylogenetic species. Hundred twenty-six genes (3.3% were identified as ORFans. Conclusions: Microbial culturomics can dramatically improve the characterization of the food and environmental microbiota repertoire, deciphering new bacterial species and new genes. Further studies will clarify the geographic specificity and the putative role of these new microbes and their related functional genetic content in environment, health, and disease.

  20. Microbial culturomics unravels the halophilic microbiota repertoire of table salt: description of Gracilibacillus massiliensis sp. nov.

    Science.gov (United States)

    Diop, Awa; Khelaifia, Saber; Armstrong, Nicholas; Labas, Noémie; Fournier, Pierre-Edouard; Raoult, Didier; Million, Matthieu

    2016-01-01

    Microbial culturomics represents an ongoing revolution in the characterization of environmental and human microbiome. By using three media containing high salt concentration (100, 150, and 200 g/L), the halophilic microbial culturome of a commercial table salt was determined. Eighteen species belonging to the Terrabacteria group were isolated including eight moderate halophilic and 10 halotolerant bacteria. Gracilibacillus massiliensis sp. nov., type strain Awa-1 T (=CSUR P1441=DSM 29726), is a moderately halophilic gram-positive, non-spore-forming rod, and is motile by using a flagellum. Strain Awa-1 T shows catalase activity but no oxidase activity. It is not only an aerobic bacterium but also able to grow in anaerobic and microaerophilic atmospheres. The draft genome of G. massiliensis is 4,207,226 bp long, composed of 13 scaffolds with 36.05% of G+C content. It contains 3,908 genes (3,839 protein-coding and 69 RNA genes). At least 1,983 (52%) orthologous proteins were not shared with the closest phylogenetic species. Hundred twenty-six genes (3.3%) were identified as ORFans. Microbial culturomics can dramatically improve the characterization of the food and environmental microbiota repertoire, deciphering new bacterial species and new genes. Further studies will clarify the geographic specificity and the putative role of these new microbes and their related functional genetic content in environment, health, and disease.

  1. Methylohalobius crimeensis gen. nov., sp. nov., a moderately halophilic, methanotrophic bacterium isolated from hypersaline lakes of Crimea.

    Science.gov (United States)

    Heyer, Jürgen; Berger, Ursula; Hardt, Martin; Dunfield, Peter F

    2005-09-01

    A novel genus and species are proposed for two strains of methanotrophic bacteria isolated from hypersaline lakes in the Crimean Peninsula of Ukraine. Strains 10Ki(T) and 4Kr are moderate halophiles that grow optimally at 1-1.5 M (5.8-8.7%, w/v) NaCl and tolerate NaCl concentrations from 0.2 M up to 2.5 M (1.2-15%). This optimum and upper limit are the highest for any methanotrophic bacterium known to date. The strains are Gram-negative, aerobic, non-pigmented, motile, coccoid to spindle-shaped bacteria that grow on methane or methanol only and utilize the ribulose monophosphate pathway for carbon assimilation. They are neutrophilic (growth occurs only in the range pH 6.5-7.5) and mesophilic (optimum growth occurs at 30 degrees C). On the basis of 16S rRNA gene sequence phylogeny, strains 10Ki(T) and 4Kr represent a type I methanotroph within the 'Gammaproteobacteria'. However, the 16S rRNA gene sequence displays <91.5 % identity to any public-domain sequence. The most closely related methanotrophic bacterium is the thermophilic strain HB. The DNA G+C content is 58.7 mol%. The major phospholipid fatty acids are 18:1omega7 (52-61%), 16:0 (22-23%) and 16:1omega7 (14-20%). The dominance of 18:1 over 16:0 and 16:1 fatty acids is unique among known type I methanotrophs. The data suggest that strains 10Ki(T) and 4Kr should be considered as belonging to a novel genus and species of type I methanotrophic bacteria, for which the name Methylohalobius crimeensis gen. nov., sp. nov. is proposed. Strain 10Ki(T) (=DSM 16011(T)=ATCC BAA-967(T)) is the type strain.

  2. Cloning, characterization and analysis of cat and ben genes from the phenol degrading halophilic bacterium Halomonas organivorans.

    Directory of Open Access Journals (Sweden)

    Maria de Lourdes Moreno

    Full Text Available BACKGROUND: Extensive use of phenolic compounds in industry has resulted in the generation of saline wastewaters that produce significant environmental contamination; however, little information is available on the degradation of phenolic compounds in saline conditions. Halomonas organivorans G-16.1 (CECT 5995(T is a moderately halophilic bacterium that we isolated in a previous work from saline environments of South Spain by enrichment for growth in different pollutants, including phenolic compounds. PCR amplification with degenerate primers revealed the presence of genes encoding ring-cleaving enzymes of the β-ketoadipate pathway for aromatic catabolism in H. organivorans. FINDINGS: The gene cluster catRBCA, involved in catechol degradation, was isolated from H. organivorans. The genes catA, catB, catC and the divergently transcribed catR code for catechol 1,2-dioxygenase (1,2-CTD, cis,cis-muconate cycloisomerase, muconolactone delta-isomerase and a LysR-type transcriptional regulator, respectively. The benzoate catabolic genes (benA and benB are located flanking the cat genes. The expression of cat and ben genes by phenol and benzoic acid was shown by RT-PCR analysis. The induction of catA gene by phenol and benzoic acid was also probed by the measurement of 1,2-CTD activity in H. organivorans growth in presence of these inducers. 16S rRNA and catA gene-based phylogenies were established among different degrading bacteria showing no phylogenetic correlation between both genes. CONCLUSIONS/SIGNIFICANCE: In this work, we isolated and determined the sequence of a gene cluster from a moderately halophilic bacterium encoding ortho-pathway genes involved in the catabolic metabolism of phenol and analyzed the gene organization, constituting the first report characterizing catabolic genes involved in the degradation of phenol in moderate halophiles, providing an ideal model system to investigate the potential use of this group of extremophiles in

  3. An experimental point of view on hydration/solvation in halophilic proteins.

    Science.gov (United States)

    Talon, Romain; Coquelle, Nicolas; Madern, Dominique; Girard, Eric

    2014-01-01

    Protein-solvent interactions govern the behaviors of proteins isolated from extreme halophiles. In this work, we compared the solvent envelopes of two orthologous tetrameric malate dehydrogenases (MalDHs) from halophilic and non-halophilic bacteria. The crystal structure of the MalDH from the non-halophilic bacterium Chloroflexus aurantiacus (Ca MalDH) solved, de novo, at 1.7 Å resolution exhibits numerous water molecules in its solvation shell. We observed that a large number of these water molecules are arranged in pentagonal polygons in the first hydration shell of Ca MalDH. Some of them are clustered in large networks, which cover non-polar amino acid surface. The crystal structure of MalDH from the extreme halophilic bacterium Salinibacter ruber (Sr) solved at 1.55 Å resolution shows that its surface is strongly enriched in acidic amino acids. The structural comparison of these two models is the first direct observation of the relative impact of acidic surface enrichment on the water structure organization between a halophilic protein and its non-adapted counterpart. The data show that surface acidic amino acids disrupt pentagonal water networks in the hydration shell. These crystallographic observations are discussed with respect to halophilic protein behaviors in solution.

  4. Glycosaminoglycans are involved in pathogen adherence to corneal epithelial cells differently for Gram-positive and Gram-negative bacteria

    Directory of Open Access Journals (Sweden)

    Beatriz García

    2016-11-01

    Full Text Available The epithelium of the cornea is continuously exposed to pathogens, and adhesion to epithelial cells is regarded as an essential first step in bacterial pathogenesis. In this article, the involvement of glycosaminoglycans in the adhesion of various pathogenic bacteria to corneal epithelial cells is analyzed. All microorganisms use glycosaminoglycans as receptors, but arranged in different patterns depending on the Gram-type of the bacterium. The heparan sulfate chains of syndecans are the main receptors, though other molecular species also seem to be involved, particularly in Gram-negative bacteria. Adherence is inhibited differentially by peptides, including heparin binding sequences, indicating the participation of various groups of Gram-positive and -negative adhesins. The length of the saccharides produces a major effect, and low molecular weight chains inhibit the binding of Gram-negative microorganisms but increase the adherence of Gram-positives. Pathogen adhesion appears to occur preferentially through sulfated domains, and is very dependent on N- and 6-O-sulfation of the glucosamine residue and, to a lesser extent, 2-O sulfation of uronic acid. These data show the differential use of corneal receptors, which could facilitate the development of new anti-infective strategies.

  5. Amino acids in cell wall of Gram-positive bacterium Micrococcus sp. hsn08 with flocculation activity on Chlorella vulgaris biomass.

    Science.gov (United States)

    Li, Yi; Xu, Yanting; Zheng, Tianling; Wang, Hailei

    2018-02-01

    The aim of this work was to investigate the flocculation mechanism by Gram-positive bacterium, Micrococcus sp. hsn08 as a means for harvesting Chlorella vulgaris biomass. Bacterial cells of Micrococcus sp. hsn08 were added into algal culture to harvest algal cells through direct contacting with algae to form flocs. Viability dependence test confirmed that flocculation activity does not depend on live bacteria, but on part of the peptidoglycan. The further investigation has determined that amino acids in cell wall play an important role to flocculate algal cells. Positively charged calcium can combine bacterial and algal cells together, and form a bridge between them, thereby forming the flocs, suggesting that ions bridging is the main flocculation mechanism. These results suggest that bacterial cells of Micrococcus sp. hsn08 can be applied to harvest microalgae biomass with the help of amino acids in cell wall. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The effect of high ionic strength on neptunium (V) adsorption to a halophilic bacterium

    Science.gov (United States)

    Ams, David A.; Swanson, Juliet S.; Szymanowski, Jennifer E. S.; Fein, Jeremy B.; Richmann, Michael; Reed, Donald T.

    2013-06-01

    The mobility of neptunium (V) in subsurface high ionic strength aqueous systems may be strongly influenced by adsorption to the cell wall of the halophilic bacteria Chromohalobacter sp. This study is the first to evaluate the adsorption of neptunium (V) to the surface of a halophilic bacterium as a function of pH from approximately 2 to 10 and at ionic strengths of 2 and 4 M. This is also the first study to evaluate the effects of carbonate complexation with neptunium (V) on adsorption to whole bacterial cells under high pH conditions. A thermodynamically-based surface complexation model was adapted to describe experimental adsorption data under high ionic strength conditions where traditional corrections for aqueous ion activity are invalid. Adsorption of neptunium (V) was rapid and reversible under the conditions of the study. Adsorption was significant over the entire pH range evaluated for both ionic strength conditions and was shown to be dependent on the speciation of the sites on the bacterial surface and neptunium (V) in solution. Adsorption behavior was controlled by the relatively strong electrostatic attraction of the positively charged neptunyl ion to the negatively charged bacterial surface at pH below circum-neutral. At pH above circum-neutral, the adsorption behavior was controlled by the presence of negatively charged neptunium (V) carbonate complexes resulting in decreased adsorption, although adsorption was still significant due to the adsorption of negatively charged neptunyl-carbonate species. Adsorption in 4 M NaClO4 was enhanced relative to adsorption in 2 M NaClO4 over the majority of the pH range evaluated, likely due to the effect of increasing aqueous ion activity at high ionic strength. The protonation/deprotonation characteristics of the cell wall of Chromohalobacter sp. were evaluated by potentiometric titrations in 2 and 4 M NaClO4. Bacterial titration results indicated that Chromohalobacter sp. exhibits similar proton buffering

  7. Purification and characterization of an extreme halothermophilic protease from a halophilic bacterium Chromohalobacter sp. TVSP101

    Directory of Open Access Journals (Sweden)

    Malashetty Vidyasagar

    2009-03-01

    Full Text Available An extreme halophilic bacterium was isolated from solar saltern samples and identified based on biochemical tests and 16S r RNA sequencing as Chromohalobacter sp. strain TVSP101. The halophilic protease was purified using ultrafiltration, ethanol precipitation, hydrophobic interaction column chromatography and gel permeation chromatography to 180 fold with 22% yield. The molecular mass of the protease determined by SDS PAGE was 66 kDa. The purified enzyme was salt dependent for its activity and stability with an optimum of 4.5 M NaCl. The optimum temperature for maximum protease activity was 75°C. The protease was optimally active at pH 8 and retained more than 80% of its activity in the range of pH 7-10. Sucrose and glycine at 10% (w/v were the most effective osmolytes, retained 100% activity in the absence of NaCl. The activity was completely inhibited by ZnCl2 (2 mM, 0.1% SDS and PMSF (1mM. The enzyme was not inhibited by 1mM of pepstatin, EDTA and PCMB. The protease was active and retained 100% it activity in 10% (v/v DMSO, DMF, ethanol and acetone.

  8. Different Use of Cell Surface Glycosaminoglycans As Adherence Receptors to Corneal Cells by Gram Positive and Gram Negative Pathogens

    Science.gov (United States)

    García, Beatriz; Merayo-Lloves, Jesús; Rodríguez, David; Alcalde, Ignacio; García-Suárez, Olivia; Alfonso, José F.; Baamonde, Begoña; Fernández-Vega, Andrés; Vazquez, Fernando; Quirós, Luis M.

    2016-01-01

    The epithelium of the cornea is continuously exposed to pathogens, and adhesion to epithelial cells is regarded as an essential first step in bacterial pathogenesis. In this article, the involvement of glycosaminoglycans in the adhesion of various pathogenic bacteria to corneal epithelial cells is analyzed. All microorganisms use glycosaminoglycans as receptors, but arranged in different patterns depending on the Gram-type of the bacterium. The heparan sulfate chains of syndecans are the main receptors, though other molecular species also seem to be involved, particularly in Gram-negative bacteria. Adherence is inhibited differentially by peptides, including heparin binding sequences, indicating the participation of various groups of Gram-positive, and -negative adhesins. The length of the saccharides produces a major effect, and low molecular weight chains inhibit the binding of Gram-negative microorganisms but increase the adherence of Gram-positives. Pathogen adhesion appears to occur preferentially through sulfated domains, and is very dependent on N- and 6-O-sulfation of the glucosamine residue and, to a lesser extent, 2-O sulfation of uronic acid. These data show the differential use of corneal receptors, which could facilitate the development of new anti-infective strategies. PMID:27965938

  9. Identification of Multiple Soluble Fe(III Reductases in Gram-Positive Thermophilic Bacterium Thermoanaerobacter indiensis BSB-33

    Directory of Open Access Journals (Sweden)

    Subrata Pal

    2014-01-01

    Full Text Available Thermoanaerobacter indiensis BSB-33 has been earlier shown to reduce Fe(III and Cr(VI anaerobically at 60°C optimally. Further, the Gram-positive thermophilic bacterium contains Cr(VI reduction activity in both the membrane and cytoplasm. The soluble fraction prepared from T. indiensis cells grown at 60°C was found to contain the majority of Fe(III reduction activity of the microorganism and produced four distinct bands in nondenaturing Fe(III reductase activity gel. Proteins from each of these bands were partially purified by chromatography and identified by mass spectrometry (MS with the help of T. indiensis proteome sequences. Two paralogous dihydrolipoamide dehydrogenases (LPDs, thioredoxin reductase (Trx, NADP(H-nitrite reductase (Ntr, and thioredoxin disulfide reductase (Tdr were determined to be responsible for Fe(III reductase activity. Amino acid sequence and three-dimensional (3D structural similarity analyses of the T. indiensis Fe(III reductases were carried out with Cr(VI reducing proteins from other bacteria. The two LPDs and Tdr showed very significant sequence and structural identity, respectively, with Cr(VI reducing dihydrolipoamide dehydrogenase from Thermus scotoductus and thioredoxin disulfide reductase from Desulfovibrio desulfuricans. It appears that in addition to their iron reducing activity T. indiensis LPDs and Tdr are possibly involved in Cr(VI reduction as well.

  10. Nesterenkonia sp. strain F, a halophilic bacterium producing acetone, butanol, and ethanol under aerobic conditions.

    Science.gov (United States)

    Amiri, Hamid; Azarbaijani, Reza; Parsa Yeganeh, Laleh; Shahzadeh Fazeli, Abolhassan; Tabatabaei, Meisam; Salekdeh, Ghasem Hosseini; Karimi, Keikhosro

    2016-01-04

    The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol, and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid, and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50, and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid, and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp., and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated.

  11. Molecular Mechanisms of Adaptation of the Moderately Halophilic Bacterium Halobacillis halophilus to Its Environment

    Directory of Open Access Journals (Sweden)

    Inga Hänelt

    2013-02-01

    Full Text Available The capability of osmoadaptation is a prerequisite of organisms that live in an environment with changing salinities. Halobacillus halophilus is a moderately halophilic bacterium that grows between 0.4 and 3 M NaCl by accumulating both chloride and compatible solutes as osmolytes. Chloride is absolutely essential for growth and, moreover, was shown to modulate gene expression and activity of enzymes involved in osmoadaptation. The synthesis of different compatible solutes is strictly salinity- and growth phase-dependent. This unique hybrid strategy of H. halophilus will be reviewed here taking into account the recently published genome sequence. Based on identified genes we will speculate about possible scenarios of the synthesis of compatible solutes and the uptake of potassium ion which would complete our knowledge of the fine-tuned osmoregulation and intracellular osmolyte balance in H. halophilus.

  12. Effects of ionic strength on the coordination of Eu(III) and Cm(III) to a Gram-negative bacterium, Paracoccus denitrificans

    International Nuclear Information System (INIS)

    Ozaki, T.; Ohnuki, T.; Kimura, T.; Francis, A.J.

    2006-01-01

    We studied the effect of ionic strength on the interactions of Europium(III) and Curium(III) with a Gram-negative bacterium Paracoccus denitrificans. Bacterial cells grown in 0.5-, 3.5-, and 5.0% NaCl were used in adsorption experiments and laser experiments that were performed at the same ionic strengths as those in the original growth media. The distribution ratio (log K d ) for Eu(III) and Cm(III) was determined at pHs 3-5. To elucidate the coordination environment of Eu(III) adsorbed on P. denitrificans, we estimated the number of water molecules in the inner sphere and strength of the ligand field by time-resolved laser-induced fluorescence spectroscopy (TRLFS) at pHs 4-6. The log K d of Eu(III) and Cm(III) increased with an increase of pH at all ionic strengths because there was less competition for ligands in cells with H + at higher pHs, wherein less H + was present in solution: cation adsorption generally occurs through an exchange with H + on the functional groups of coordination sites. No significant differences were observed in the log K d of Eu(III) and Cm(III) at each pH in 0.5-, 3.5-, and 5.0% NaCl solutions, though competition for ligands with Na + would be expected to increase at higher NaCl concentrations. The log K d of Eu(III) was almost equivalent to that of Cm(III) under all the experimental conditions. TRLFS showed that the coordination environments of Eu(III) did not differ from each other at 0.5-, 3.5-, and 5.0% NaCl at pHs 4-6. TRLFS also showed that the characteristic of the coordination environment of Eu(III) on P. denitrificans was similar to that on a halophile, Nesterenkonia halobia, while it significantly differed from that on a non-halophile, Pseudomonas putida. These findings indicate that the number of coordination sites for Eu(III) on P. denitrificans, whose cell surface may have similar structures to that of halophiles, increased with increasing ionic strength, though their structure remained unchanged. (orig.)

  13. Perchlorate and halophilic prokaryotes: implications for possible halophilic life on Mars.

    Science.gov (United States)

    Oren, Aharon; Elevi Bardavid, Rahel; Mana, Lily

    2014-01-01

    In view of the finding of perchlorate among the salts detected by the Phoenix Lander on Mars, we investigated the relationships of halophilic heterotrophic microorganisms (archaea of the family Halobacteriaceae and the bacterium Halomonas elongata) toward perchlorate. All strains tested grew well in NaCl-based media containing 0.4 M perchlorate, but at the highest perchlorate concentrations, tested cells were swollen or distorted. Some species (Haloferax mediterranei, Haloferax denitrificans, Haloferax gibbonsii, Haloarcula marismortui, Haloarcula vallismortis) could use perchlorate as an electron acceptor for anaerobic growth. Although perchlorate is highly oxidizing, its presence at a concentration of 0.2 M for up to 2 weeks did not negatively affect the ability of a yeast extract-based medium to support growth of the archaeon Halobacterium salinarum. These findings show that presence of perchlorate among the salts on Mars does not preclude the possibility of halophilic life. If indeed the liquid brines that may exist on Mars are inhabited by salt-requiring or salt-tolerant microorganisms similar to the halophiles on Earth, presence of perchlorate may even be stimulatory when it can serve as an electron acceptor for respiratory activity in the anaerobic Martian environment.

  14. Microbiological method for radiation sterilization (II). Identification procedure of gram positive bacteria by using BBL CRYSTAL GP identification kit

    International Nuclear Information System (INIS)

    Koshikawa, Tomihiko

    2004-01-01

    The part II in this title series describes details of the commercially available BBL CRYSTAL GP Identification Kit with the software (Becton, Dickinson and Co., Ltd.), by which identification of Gram positive bacteria as well as their number becoming easier in the radiation sterilization of medical devices. Isolation of a bacterium has to be confirmed by microscopy and its Gram positive property, by the Gram staining. The exponentially growing bacteria are to be inoculated in the Kit and cultured for 18-24 hr at 37 deg C with the lid attached by substrates for identification. Reactions to substrates are to be judged by CRYSTAL auto-reader, which is further to be searched by the computer software (code-book) for final identification. For possible misidentification, re-isolation of the bacterium, prolonged culture, concentrated inoculation and re-consideration for ranking of identification the software provides are necessary as well as other identification approaches. Representative bacteria as the bioburden are spp. of Bacilli, Corynebacteria, Staphylococci and Micrococci. (N.I.)

  15. Comparative Proteomic Analysis of Desulfotomaculum reducens MI-1: Insights into the Metabolic Versatility of a Gram-positive Sulfate and Metal-reducing Bacterium

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    Anne Elyse Otwell

    2016-02-01

    Full Text Available The proteomes of the metabolically versatile and poorly characterized Gram-positive bacterium Desulfotomaculum reducens MI-1 were compared across four cultivation conditions including sulfate reduction, soluble Fe(III reduction, insoluble Fe(III reduction, and pyruvate fermentation. Collectively across conditions, we observed at high confidence ~38% of genome-encoded proteins. Here, we focus on proteins that display significant differential abundance on conditions tested. To the best of our knowledge, this is the first full-proteome study focused on a Gram-positive organism grown either on sulfate or metal-reducing conditions. Several proteins with uncharacterized function encoded within heterodisulfide reductase (hdr-containing loci were upregulated on either sulfate (Dred_0633-4, Dred_0689-90, and Dred_1325-30 or Fe(III-citrate-reducing conditions (Dred_0432-3 and Dred_1778-84. Two of these hdr-containing loci display homology to recently described flavin-based electron bifurcation (FBEB pathways (Dred_1325-30 and Dred_1778-84. Additionally, we propose that a cluster of proteins, which is homologous to a described FBEB lactate dehydrogenase (LDH complex, is performing lactate oxidation in D. reducens (Dred_0367-9. Analysis of the putative sulfate reduction machinery in D. reducens revealed that most of these proteins are constitutively expressed across cultivation conditions tested. In addition, peptides from the single multiheme c-type cytochrome (MHC in the genome were exclusively observed on the insoluble Fe(III condition, suggesting that this MHC may play a role in reduction of insoluble metals.

  16. Bio sorption of some Rare Earth Elements and Yttrium by Gram Positive and Gram Negative Bacteria

    International Nuclear Information System (INIS)

    Ibrahim, H.A.

    2012-01-01

    The separate bio sorption of the REEs La, Sm, Eu and Dy together with yttrium upon the Gram positive bacteria Bacillus subtilis (B.subtilis) and Bacillus Licheniformis (B. Licheniformis),the Gram negative bacterium Escherichia coli (E. coli ) and Saccharomyces cervisiae (Yeast) was studied. The revelant factors of ph 1-6, contact time (30-180 min), the initial rare earth concentration (50-200 mg/l) have been studied. The amount of the accumulated element was strongly affected by its concentration.In addition, bio sorptive fractionation of Y and the studied REEs from a solution containing a mixture of these elements was also studied. From the obtained data, it was found that Langmuir isotherm model for both B.licheniformis and E.coli gives a best fit for the studied elements over the working range of concentration (50-200 mg/I). Transmission electron microscopy exhibited accumulation throughout the bacterial cell with some granular deposits in both the cell periphery and cytoplasm

  17. Septicemia caused by the gram-negative bacterium CDC IV c-2 in an immunocompromised human.

    OpenAIRE

    Dan, M; Berger, S A; Aderka, D; Levo, Y

    1986-01-01

    A 37-year-old man with plasma cell leukemia developed nonfatal septicemia caused by the gram-negative bacterium CDC IV c-2. Recovery followed appropriate treatment with antibiotics. The biochemical features of this organism are reviewed.

  18. Halophilic Nuclease from a Moderately Halophilic Micrococcus varians

    Science.gov (United States)

    Kamekura, Masahiro; Onishi, Hiroshi

    1974-01-01

    The moderately halophilic bacterium Micrococcus varians, isolated from soy sauce mash, produced extracellular nuclease when cultivated aerobically in media containing 1 to 4 M NaCl or KCl. The enzyme, purified to an electrophoretically homogeneous state, had both ribonuclease and deoxyribonuclease activities. The nuclease had maximal activity in the presence of 2.9 M NaCl or 2.1 M KCl at 40 C. The enzymatic activity was lost by dialysis against low-salt buffer, whereas when the inactivated enzyme was dialyzed against 3.4 M NaCl buffer as much as 77% of the initial activity could be restored. Images PMID:4852218

  19. Fermentation of glycolate by a pure culture of a strictly anaerobic gram-positive bacterium belonging to the family Lachnospiraceae.

    Science.gov (United States)

    Janssen, Peter H; Hugenholtz, Philip

    2003-05-01

    The component bacteria of a three-membered mixed culture able to ferment glycolate to acetate, propionate and CO(2) were isolated in pure culture. All three strains were strict anaerobes that, on the basis of comparative 16S rRNA gene sequence analysis, belonged to the order Clostridiales in the phylum Firmicutes (low G+C gram-positive bacteria). Two of the strains were not involved in glycolate metabolism. The third, the glycolate-fermenting strain 19gly4 (DSM 11261), was related to members of the family Lachnospiraceae. The cells of strain 19gly4 were oval- to lemon-shaped, 0.85 microm long and 0.65 microm in diameter, occurring singly, in pairs, or in chains of up to 30 cells. Strain 19gly4 fermented glycolate or fumarate to acetate, succinate, and CO(2). Hydrogen was not formed, and strain 19gly4 was able to grow on glycolate in pure culture without any syntrophic hydrogen transfer and without the use of an external electron acceptor. There was no evidence for homoacetogenic metabolism. This bacterium therefore differs in metabolism from previously reported glycolate-utilising anaerobes.

  20. Halophilic Bacteria as a Source of Novel Hydrolytic Enzymes

    Science.gov (United States)

    de Lourdes Moreno, María; Pérez, Dolores; García, María Teresa; Mellado, Encarnación

    2013-01-01

    Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. The halotolerance of many enzymes derived from halophilic bacteria can be exploited wherever enzymatic transformations are required to function under physical and chemical conditions, such as in the presence of organic solvents and extremes in temperature and salt content. In recent years, different screening programs have been performed in saline habitats in order to isolate and characterize novel enzymatic activities with different properties to those of conventional enzymes. Several halophilic hydrolases have been described, including amylases, lipases and proteases, and then used for biotechnological applications. Moreover, the discovery of biopolymer-degrading enzymes offers a new solution for the treatment of oilfield waste, where high temperature and salinity are typically found, while providing valuable information about heterotrophic processes in saline environments. In this work, we describe the results obtained in different screening programs specially focused on the diversity of halophiles showing hydrolytic activities in saline and hypersaline habitats, including the description of enzymes with special biochemical properties. The intracellular lipolytic enzyme LipBL, produced by the moderately halophilic bacterium Marinobacter lipolyticus, showed advantages over other lipases, being an enzyme active over a wide range of pH values and temperatures. The immobilized LipBL derivatives obtained and tested in regio- and enantioselective reactions, showed an excellent behavior in the production of free polyunsaturated fatty acids (PUFAs). On the other hand, the extremely halophilic bacterium, Salicola marasensis sp. IC10 showing lipase and protease activities, was studied for its ability to produce promising enzymes in terms of its resistance to temperature and salinity. PMID:25371331

  1. Halophilic Bacteria as a Source of Novel Hydrolytic Enzymes

    Directory of Open Access Journals (Sweden)

    Encarnación Mellado

    2013-01-01

    Full Text Available Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. The halotolerance of many enzymes derived from halophilic bacteria can be exploited wherever enzymatic transformations are required to function under physical and chemical conditions, such as in the presence of organic solvents and extremes in temperature and salt content. In recent years, different screening programs have been performed in saline habitats in order to isolate and characterize novel enzymatic activities with different properties to those of conventional enzymes. Several halophilic hydrolases have been described, including amylases, lipases and proteases, and then used for biotechnological applications. Moreover, the discovery of biopolymer-degrading enzymes offers a new solution for the treatment of oilfield waste, where high temperature and salinity are typically found, while providing valuable information about heterotrophic processes in saline environments. In this work, we describe the results obtained in different screening programs specially focused on the diversity of halophiles showing hydrolytic activities in saline and hypersaline habitats, including the description of enzymes with special biochemical properties. The intracellular lipolytic enzyme LipBL, produced by the moderately halophilic bacterium Marinobacter lipolyticus, showed advantages over other lipases, being an enzyme active over a wide range of pH values and temperatures. The immobilized LipBL derivatives obtained and tested in regio- and enantioselective reactions, showed an excellent behavior in the production of free polyunsaturated fatty acids (PUFAs. On the other hand, the extremely halophilic bacterium, Salicola marasensis sp. IC10 showing lipase and protease activities, was studied for its ability to produce promising enzymes in terms of its resistance to temperature and salinity.

  2. Procalcitonin levels in gram-positive, gram-negative, and fungal bloodstream infections.

    Science.gov (United States)

    Leli, Christian; Ferranti, Marta; Moretti, Amedeo; Al Dhahab, Zainab Salim; Cenci, Elio; Mencacci, Antonella

    2015-01-01

    Procalcitonin (PCT) can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR) 3.4-44.1) bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6-7.6) or fungal (0.5 ng/mL, IQR 0.4-1) infections (P Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919-0.969, P Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9-48.5 versus 3.5 ng/mL, IQR 0.8-21.5; P Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

  3. Gram-negative, but not Gram-positive, bacteria elicit strong PGE2 production in human monocytes.

    Science.gov (United States)

    Hessle, Christina C; Andersson, Bengt; Wold, Agnes E

    2003-12-01

    Gram-positive and Gram-negative bacteria induce different cytokine patterns in human mononuclear cells. We have seen that Gram-positives preferentially induce IL-12 and TNF-alpha, whereas Gram-negatives induce more IL-10, IL-6, and IL-8. In this study, we compared the capacity of these two groups of bacteria to induce PGE2. Monocytes stimulated with Gram-negative bacterial species induced much more PGE2 than did Gram-positive bacteria (5600 +/- 330 vs. 1700 +/- 670 pg/mL, p Gram-positive and Gram-negative bacteria. We suggest that Gram-positive and Gram-negative bacteria may stimulate different innate effector functions; Gram-positive bacteria promoting cell-mediated effector functions whereas Gram-negative bacteria inducing mediators inhibiting the same.

  4. Procalcitonin Levels in Gram-Positive, Gram-Negative, and Fungal Bloodstream Infections

    Directory of Open Access Journals (Sweden)

    Christian Leli

    2015-01-01

    Full Text Available Procalcitonin (PCT can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR 3.4–44.1 bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6–7.6 or fungal (0.5 ng/mL, IQR 0.4–1 infections (P<0.0001. Receiver operating characteristic analysis showed an area under the curve (AUC for PCT of 0.765 (95% CI 0.725–0.805, P<0.0001 in discriminating Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919–0.969, P<0.0001 in discriminating Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9–48.5 versus 3.5 ng/mL, IQR 0.8–21.5; P<0.0001. This study suggests that PCT may be of value to distinguish Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

  5. Purification and characterization of an extracellular haloalkaline serine protease from the moderately halophilic bacterium, Bacillus iranensis (X5B).

    Science.gov (United States)

    Ghafoori, Hossein; Askari, Mansoure; Sarikhan, Sajjad

    2016-03-01

    This study reports the purification and characterization of an extracellular haloalkaline serine protease from the moderately halophilic bacterium, Bacillus iranensis, strain X5B. The enzyme was purified to homogeneity by acetone precipitation, ultrafiltration and carboxymethyl (CM) cation exchange chromatography, respectively. The purified protease was a monomeric enzyme with a relative molecular mass of 48-50 kDa and it was inhibited by PMSF indicating that it is a serine-protease. The optimum pH, temperature and NaCl concentration were 9.5, 35 °C and 0.98 M, respectively. The enzyme showed a significant tolerance to salt and alkaline pH. It retained approximately 50% of activity at 2.5 M NaCl and about 70% of activity at highly alkaline pH of 11.0; therefore, it was a moderately halophilic and also can be activated by metals, especially by Ca(2+). The specific activity of the purified protease was measured to be 425.23 μmol of tyrosine/min per mg of protein using casein as a substrate. The apparent K m and V max values were 0.126 mM and 0.523 mM/min, respectively and the accurate value of k cat was obtained as 3.284 × 10(-2) s(-1). These special and important characteristics make this serine protease as valuable tool for industrial applications.

  6. Low Water Activity Induces the Production of Bioactive Metabolites in Halophilic and Halotolerant Fungi

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    Nina Gunde-Cimerman

    2010-12-01

    Full Text Available The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice, for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, the selected fungi are exposed to environmental extremes, and therefore the production of bioactive metabolites was tested under both standard growth conditions for mesophilic microorganisms, and at high NaCl and sugar concentrations and low growth temperatures. The results indicate that selected halotolerant and halophilic species synthesize specific bioactive metabolites under conditions that represent stress for non-adapted species. Furthermore, adaptation at the level of the chemical nature of the solute lowering the water activity of the medium was observed. Increased salt concentrations resulted in higher hemolytic activity, particularly within species dominating the salterns. The appearance of antibacterial potential under stress conditions was seen in the similar pattern of fungal species as for hemolysis. The active extracts exclusively affected the growth of the Gram-positive bacterium tested, Bacillus subtilis. None of the extracts tested showed inhibition of acetylcholinesterase activity.

  7. Transformation of gram positive bacteria by sonoporation

    Science.gov (United States)

    Yang, Yunfeng; Li, Yongchao

    2014-03-11

    The present invention provides a sonoporation-based method that can be universally applied for delivery of compounds into Gram positive bacteria. Gram positive bacteria which can be transformed by sonoporation include, for example, Bacillus, Streptococcus, Acetobacterium, and Clostridium. Compounds which can be delivered into Gram positive bacteria via sonoporation include nucleic acids (DNA or RNA), proteins, lipids, carbohydrates, viruses, small organic and inorganic molecules, and nano-particles.

  8. Noncontiguous finished genome sequence and description of Virgibacillus massiliensis sp. nov., a moderately halophilic bacterium isolated from human gut

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    S. Khelaifia

    2015-11-01

    Full Text Available Strain Vm-5T was isolated from the stool specimen of a 10-year-old Amazonian boy. This bacterium is a Gram-positive, strictly aerobic rod, motile by a polar flagellum. Here we describe its phenotypic characteristics and complete genome sequence. The 4 353 177 bp long genome exhibits a G + C content of 36.87% and contains 4394 protein-coding and 125 predicted RNA genes. Phylogenetically and genetically, strain Vm-c is a member of the genus Virgibacillus but is distinct enough to be classified as a new species. We propose the creation of V. massiliensis sp. nov., whose type strain is strain Vm-5T (CSUR P971 = DSM 28587.

  9. Diagnosing periprosthetic infection: false-positive intraoperative Gram stains.

    Science.gov (United States)

    Oethinger, Margret; Warner, Debra K; Schindler, Susan A; Kobayashi, Hideo; Bauer, Thomas W

    2011-04-01

    Intraoperative Gram stains have a reported low sensitivity but high specificity when used to help diagnose periprosthetic infections. In early 2008, we recognized an unexpectedly high frequency of apparent false-positive Gram stains from revision arthroplasties. The purpose of this report is to describe the cause of these false-positive test results. We calculated the sensitivity and specificity of all intraoperative Gram stains submitted from revision arthroplasty cases during a 3-month interval using microbiologic cultures of the same samples as the gold standard. Methods of specimen harvesting, handling, transport, distribution, specimen processing including tissue grinding/macerating, Gram staining, and interpretation were studied. After a test modification, results of specimens were prospectively collected for a second 3-month interval, and the sensitivity and specificity of intraoperative Gram stains were calculated. The retrospective review of 269 Gram stains submitted from revision arthroplasties indicated historic sensitivity and specificity values of 23% and 92%, respectively. Systematic analysis of all steps of the procedure identified Gram-stained but nonviable bacteria in commercial broth reagents used as diluents for maceration of periprosthetic membranes before Gram staining and culture. Polymerase chain reaction and sequencing showed mixed bacterial DNA. Evaluation of 390 specimens after initiating standardized Millipore filtering of diluent fluid revealed a reduced number of positive Gram stains, yielding 9% sensitivity and 99% specificity. Clusters of false-positive Gram stains have been reported in other clinical conditions. They are apparently rare related to diagnosing periprosthetic infections but have severe consequences if used to guide treatment. Even occasional false-positive Gram stains should prompt review of laboratory methods. Our observations implicate dead bacteria in microbiologic reagents as potential sources of false-positive Gram

  10. The Structure of the Lipid A from the Halophilic Bacterium Spiribacter salinus M19-40T

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    Clara Barrau

    2018-04-01

    Full Text Available The study of the adaptation mechanisms that allow microorganisms to live and proliferate in an extreme habitat is a growing research field. Directly exposed to the external environment, lipopolysaccharides (LPS from Gram-negative bacteria are of great appeal as they can present particular structural features that may aid the understanding of the adaptation processes. Moreover, through being involved in modulating the mammalian immune system response in a structure-dependent fashion, the elucidation of the LPS structure can also be seen as a fundamental step from a biomedical point of view. In this paper, the lipid A structure of the LPS from Spiribacter salinus M19-40T, a halophilic gamma-proteobacteria, was characterized through chemical analyses and matrix-assisted laser desorption ionization (MALDI mass spectrometry. This revealed a mixture of mono- and bisphosphorylated penta- to tri-acylated species with the uncommon 2 + 3 symmetry and bearing an unusual 3-oxotetradecaonic acid.

  11. The Causes of Post-Operative Meningitis: The Comparison Of Gram-Negative and Gram-Positive Pathogens.

    Science.gov (United States)

    Kurtaran, Behice; Kuscu, Ferit; Ulu, Aslihan; Inal, Ayse Seza; Komur, Suheyla; Kibar, Filiz; Cetinalp, Nuri Eralp; Ozsoy, Kerem Mazhar; Arslan, Yusuf Kemal; Aksu, Hasan Salih; Tasova, Yesim

    2017-06-20

    In this study, we aim to determine the microbiological etiology in critically ill neurosurgical patients with nosocomial meningitis (NM) and show the impact of Gram-negative rods and differences of patient's characteristics, clinical and prognostic measures between Gram-negative and Gram-positive meningitis. In this prospective, one center study we reviewed all adult patients hospitalized during a 12-year period and identified pathogens isolated from post-neurosurgical cases of NM. Demographic, clinical, and treatment characteristics were noted from the medical records. Of the 134 bacterial NM patients, 78 were male and 56 were female, with a mean age of 46±15.9 and median age of 50 (18-80) years. 141 strains isolated; 82 (58.2%) were Gram negative, 59 (41.8%) were Gram positive. Most common isolated microorganism was Acinetobacter baumannii (%34.8). In comparison of mortality data shows that the patients who have meningitis with Gram-negative pathogens have higher mortality than with Gram positives (p=0.034). The duration between surgery and meningitis was shorter in Gram negative meningitis cases compared to others (p=0.045) but the duration between the diagnosis and death was shorter in Gram-positive meningitis cases compared to Gram negatives (p= 0.017). CSF protein and lactate level were higher and glucose level was lower in cases of NM with Gram negatives (p value were respectively, 0.022, 0.039 and 0.049). As conclusions; in NM, Gram-negative pathogens were seen more frequently; A.baumanni was the predominant pathogen; and NM caused by Gram negatives had worse clinical and laboratory characteristic and prognostic outcome than Gram positives.

  12. Polymers for binding of the gram-positive oral pathogen Streptococcus mutans

    Science.gov (United States)

    Magennis, Eugene P.; Francini, Nora; Mastrotto, Francesca; Catania, Rosa; Redhead, Martin; Fernandez-Trillo, Francisco; Bradshaw, David; Churchley, David; Winzer, Klaus; Alexander, Cameron

    2017-01-01

    Streptococcus mutans is the most significant pathogenic bacterium implicated in the formation of dental caries and, both directly and indirectly, has been associated with severe conditions such as multiple sclerosis, cerebrovascular and peripheral artery disease. Polymers able to selectively bind S. mutans and/or inhibit its adhesion to oral tissue in a non-lethal manner would offer possibilities for addressing pathogenicity without selecting for populations resistant against bactericidal agents. In the present work two libraries of 2-(dimethylamino)ethyl methacrylate (pDMAEMA)-based polymers were synthesized with various proportions of either N,N,N-trimethylethanaminium cationic- or sulfobetaine zwitterionic groups. These copolymers where initially tested as potential macromolecular ligands for S. mutans NCTC 10449, whilst Escherichia coli MG1655 was used as Gram-negative control bacteria. pDMAEMA-derived materials with high proportions of zwitterionic repeating units were found to be selective for S. mutans, in both isolated and S. mutans–E. coli mixed bacterial cultures. Fully sulfobetainized pDMAEMA was subsequently found to bind/cluster preferentially Gram-positive S. mutans and S. aureus compared to Gram negative E. coli and V. harveyi. A key initial stage of S. mutans pathogenesis involves a lectin-mediated adhesion to the tooth surface, thus the range of potential macromolecular ligands was further expanded by investigating two glycopolymers bearing α-mannopyranoside and β-galactopyranoside pendant units. Results with these polymers indicated that preferential binding to either S. mutans or E. coli can be obtained by modulating the glycosylation pattern of the chosen multivalent ligands without incurring unacceptable cytotoxicity in a model gastrointestinal cell line. Overall, our results allowed to identify a structure–property relationship for the potential antimicrobial polymers investigated, and suggest that preferential binding to Gram-positive S

  13. Characterization of a halophilic heterotrophic nitrification-aerobic denitrification bacterium and its application on treatment of saline wastewater.

    Science.gov (United States)

    Duan, Jinming; Fang, Hongda; Su, Bing; Chen, Jinfang; Lin, Jinmei

    2015-03-01

    A novel halophilic bacterium capable of heterotrophic nitrification-aerobic denitrification was isolated from marine sediments and identified as Vibrio diabolicus SF16. It had ability to remove 91.82% of NH4(+)-N (119.77 mg/L) and 99.71% of NO3(-)-N (136.43 mg/L). The nitrogen balance showed that 35.83% of initial NH4(+)-N (119.77 mg/L) was changed to intracellular nitrogen, and 53.98% of the initial NH4(+)-N was converted to gaseous denitrification products. The existence of napA gene further proved the aerobic denitrification ability of strain SF16. The optimum culture conditions were salinity 1-5%, sodium acetate as carbon source, C/N 10, and pH 7.5-9.5. When an aerated biological filter system inoculated with strain SF16 was employed to treat saline wastewater, the average removal efficiency of NH4(+)-N and TN reached 97.14% and 73.92%, respectively, indicating great potential of strain SF16 for future full-scale applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Mid-infrared spectroscopic assessment of nanotoxicity in gram-negative vs. gram-positive bacteria.

    Science.gov (United States)

    Heys, Kelly A; Riding, Matthew J; Strong, Rebecca J; Shore, Richard F; Pereira, M Glória; Jones, Kevin C; Semple, Kirk T; Martin, Francis L

    2014-03-07

    Nanoparticles appear to induce toxic effects through a variety of mechanisms including generation of reactive oxygen species (ROS), physical contact with the cell membrane and indirect catalysis due to remnants from manufacture. The development and subsequent increasing usage of nanomaterials has highlighted a growing need to characterize and assess the toxicity of nanoparticles, particularly those that may have detrimental health effects such as carbon-based nanomaterials (CBNs). Due to interactions of nanoparticles with some reagents, many traditional toxicity tests are unsuitable for use with CBNs. Infrared (IR) spectroscopy is a non-destructive, high throughput technique, which is unhindered by such problems. We explored the application of IR spectroscopy to investigate the effects of CBNs on Gram-negative (Pseudomonas fluorescens) and Gram-positive (Mycobacterium vanbaalenii PYR-1) bacteria. Two types of IR spectroscopy were compared: attenuated total reflection Fourier-transform infrared (ATR-FTIR) and synchrotron radiation-based FTIR (SR-FTIR) spectroscopy. This showed that Gram-positive and Gram-negative bacteria exhibit differing alterations when exposed to CBNs. Gram-positive bacteria appear more resistant to these agents and this may be due to the protection afforded by their more sturdy cell wall. Markers of exposure also vary according to Gram status; Amide II was consistently altered in Gram-negative bacteria and carbohydrate altered in Gram-positive bacteria. ATR-FTIR and SR-FTIR spectroscopy could both be applied to extract biochemical alterations induced by each CBN that were consistent across the two bacterial species; these may represent potential biomarkers of nanoparticle-induced alterations. Vibrational spectroscopy approaches may provide a novel means of fingerprinting the effects of CBNs in target cells.

  15. A novel halophilic lipase, LipBL, showing high efficiency in the production of eicosapentaenoic acid (EPA.

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    Dolores Pérez

    Full Text Available BACKGROUND: Among extremophiles, halophiles are defined as microorganisms adapted to live and thrive in diverse extreme saline environments. These extremophilic microorganisms constitute the source of a number of hydrolases with great biotechnological applications. The interest to use extremozymes from halophiles in industrial applications is their resistance to organic solvents and extreme temperatures. Marinobacter lipolyticus SM19 is a moderately halophilic bacterium, isolated previously from a saline habitat in South Spain, showing lipolytic activity. METHODS AND FINDINGS: A lipolytic enzyme from the halophilic bacterium Marinobacter lipolyticus SM19 was isolated. This enzyme, designated LipBL, was expressed in Escherichia coli. LipBL is a protein of 404 amino acids with a molecular mass of 45.3 kDa and high identity to class C β-lactamases. LipBL was purified and biochemically characterized. The temperature for its maximal activity was 80°C and the pH optimum determined at 25°C was 7.0, showing optimal activity without sodium chloride, while maintaining 20% activity in a wide range of NaCl concentrations. This enzyme exhibited high activity against short-medium length acyl chain substrates, although it also hydrolyzes olive oil and fish oil. The fish oil hydrolysis using LipBL results in an enrichment of free eicosapentaenoic acid (EPA, but not docosahexaenoic acid (DHA, relative to its levels present in fish oil. For improving the stability and to be used in industrial processes LipBL was immobilized in different supports. The immobilized derivatives CNBr-activated Sepharose were highly selective towards the release of EPA versus DHA. The enzyme is also active towards different chiral and prochiral esters. Exposure of LipBL to buffer-solvent mixtures showed that the enzyme had remarkable activity and stability in all organic solvents tested. CONCLUSIONS: In this study we isolated, purified, biochemically characterized and immobilized a

  16. Characterization of an organic solvent-tolerant thermostable glucoamylase from a halophilic isolate, Halolactibacillus sp. SK71 and its application in raw starch hydrolysis for bioethanol production.

    Science.gov (United States)

    Yu, Hui-Ying; Li, Xin

    2014-01-01

    A halophilic bacterium Halolactibacillus sp. SK71 producing extracellular glucoamylase was isolated from saline soil of Yuncheng Salt Lake, China. Enzyme production was strongly influenced by the salinity of growth medium with maximum in the presence of 5% NaCl. The glucoamylase was purified to homogeneity with a molecular mass of 78.5 kDa. It showed broad substrate specificity and raw starch hydrolyzing activity. Analysis of hydrolysis products from soluble starch by thin-layer chromatography revealed that glucose was the sole end-product, indicating the enzyme was a true glucoamylase. Optimal enzyme activity was found to be at 70°C, pH 8.0, and 7.5% NaCl. In addition, it was highly active and stable over broad ranges of temperature (0-100°C), pH (7.0-12.0), and NaCl concentration (0-20%), showing excellent thermostable, alkali stable, and halotolerant properties. Furthermore, it displayed high stability in the presence of hydrophobic organic solvents. The purified glucoamylase was applied for raw corn starch hydrolysis and subsequent bioethanol production using Saccharomyces cerevisiae. The yield in terms of grams of ethanol produced per gram of sugar consumed was 0.365 g/g, with 71.6% of theoretical yield from raw corn starch. This study demonstrated the feasibility of using enzymes from halophiles for further application in bioenergy production. © 2014 American Institute of Chemical Engineers.

  17. Planococcus salinus sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil.

    Science.gov (United States)

    Gan, Longzhan; Zhang, Heming; Tian, Jiewei; Li, Xiaoguang; Long, Xiufeng; Zhang, Yuqin; Dai, Yumei; Tian, Yongqiang

    2018-02-01

    A novel aerobic, Gram-stain-positive, motile, moderately halophilic and coccoid bacterial strain, designated LCB217 T , was isolated from a saline-alkali soil in north-western China and identified using a polyphasic taxonomic approach. Growth occurred with 3-15 % (w/v) NaCl (optimum 3-5 %), at 10-45 °C (optimum 30 °C) and at pH 7.0-9.0 (optimum pH 9.0). Strain LCB217 T contained MK-7 and MK-8 as the predominant menaquinones and anteiso-C15 : 0, iso-C14 : 0 and iso-C16 : 0 as the major fatty acids. The polar lipids from strain LCB217 T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unidentified phospholipid, one unidentified aminophospholipid and one unidentified lipid. The peptidoglycan type was A4α (l-Lys-d-Glu). Phylogenetic analysis of the 16S rRNA gene sequence showed that strain LCB217 T belonged to the genus Planococcus and was closely related to the type strains Planococcus plakortidis AS/ASP6 (II) T (98.2 % similarity), Planococcus maitriensis S1 T (97.7 %) and Planococcus salinarum ISL-16 T (97.2 %). The G+C content of the genomic DNA was 49.4 mol%. DNA-DNA relatedness values between strain LCB217 T andPlanococcusplakortidis AS/ASP6 (II) T , Planococcusmaitriensis S1 T andPlanococcussalinarum ISL-16 T were 29.5, 38.1 and 39.5 %, respectively. On the basis of the phenotypic, phylogenetic and genomic data, strain LCB217 T represents a novel species of the genus Planococcus, for which the name Planococcus salinus sp. nov. is proposed. The type strain is LCB217 T (=CGMCC 1.15685 T =KCTC 33861 T ).

  18. Marinobacter lacisalsi sp. nov., a moderately halophilic bacterium isolated from the saline-wetland wildfowl reserve Fuente de Piedra in southern Spain.

    Science.gov (United States)

    Aguilera, Margarita; Jiménez-Pranteda, Maria L; Kharroub, Karima; González-Paredes, Ana; Durban, Juan J; Russell, Nick J; Ramos-Cormenzana, Alberto; Monteoliva-Sánchez, Mercedes

    2009-07-01

    A Gram-negative, non-spore-forming, motile, moderately halophilic, aerobic, rod-shaped bacterium, designated strain FP2.5(T), was isolated from the inland hypersaline lake Fuente de Piedra, a saline-wetland wildfowl reserve located in the province of Málaga in southern Spain. Strain FP2.5(T) was subjected to a polyphasic taxonomic study. It produced colonies with a light-yellow pigment. Strain FP2.5(T) grew at salinities of 3-15 % (w/v) and at temperatures of 20-40 degrees C. The pH range for growth was 5-9. Strain FP2.5(T) was able to utilize various organic acids as sole carbon and energy source. Its major fatty acids were C(16 : 0), C(18 : 1)omega9c and C(16 : 1)omega9c. The DNA G+C content was 58.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FP2.5(T) appeared to be a member of the genus Marinobacter and clustered closely with the type strains of Marinobacter segnicrescens, Marinobacter bryozoorum and Marinobacter gudaonensis (levels of 16S rRNA gene sequence similarity of 98.1, 97.4 and 97.2 %, respectively). However, DNA-DNA relatedness between the new isolate and the type strains of its closest related Marinobacter species was low; levels of DNA-DNA relatedness between strain FP2.5(T) and M. segnicrescens LMG 23928(T), M. bryozoorum DSM 15401(T) and M. gudaonensis DSM 18066(T) were 36.3, 32.1 and 24.9 %, respectively. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, strain FP2.5(T) is considered to represent a novel species of the genus Marinobacter, for which the name Marinobacter lacisalsi sp. nov. is proposed. The type strain is FP2.5(T) (=CECT 7297(T)=LMG 24237(T)).

  19. Identification of moderately halophilic bacteria from Thai fermented fish ( pla-ra ) and proposal of Virgibacillus siamensis sp. nov.

    Science.gov (United States)

    Tanasupawat, Somboon; Chamroensaksri, Nitcha; Kudo, Takuji; Itoh, Takashi

    2010-10-01

    Forty-one isolates of moderately halophilic bacteria were isolated from fermented fish (pla-ra) in Thailand. On the basis of their phenotypic and chemotaxonomic characteristics, DNA-DNA relatedness and 16S rRNA gene sequences analyses, they were divided into six groups. The isolates in Group I to V were Gram-positive rod-shaped bacteria. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan and menaquinone with seven isoprene units (MK-7). An isolate in Group VI was a Gram-negative rod-shaped bacterium. The DNA G+C contents of tested strains ranged from 36.5-63 mol%. Ten strains (Group I) were identified as Virgibacillus dokdonensis, 13 isolates (Group II) as V. halodenitrificans, 14 isolates (Group III) as V. marismortui, 1 isolate (Group IV) as Virgibacillus sp., 2 isolates (Group V) as Bacillus vietnamnensis, and 1 isolate (Group VI) as Chromohalobacter salexigens. Isolate MS3-4 in Group IV was closely related to V. carmonensis KCTC 3819(T) (95.9%). This strain contained anteiso-C(15:0) (55.8%) and anteiso-C(17:0) (17.7%) as major cellular fatty acids and had phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid as polar lipids. The DNA G+C content of MS3-4 was 38.0 mol%. The strain from Group IV is proposed as Virgibacillus siamensis sp. nov. and MS3-4(T) is the type strain (JCM 15395(T) =PCU 312(T) =TISTR 1957(T)).

  20. Gram positive and Gram negative bacteria differ in their sensitivity to cold plasma

    Science.gov (United States)

    Mai-Prochnow, Anne; Clauson, Maryse; Hong, Jungmi; Murphy, Anthony B.

    2016-12-01

    Cold atmospheric-pressure plasma (CAP) is a relatively new method being investigated for antimicrobial activity. However, the exact mode of action is still being explored. Here we report that CAP efficacy is directly correlated to bacterial cell wall thickness in several species. Biofilms of Gram positive Bacillus subtilis, possessing a 55.4 nm cell wall, showed the highest resistance to CAP, with less than one log10 reduction after 10 min treatment. In contrast, biofilms of Gram negative Pseudomonas aeruginosa, possessing only a 2.4 nm cell wall, were almost completely eradicated using the same treatment conditions. Planktonic cultures of Gram negative Pseudomonas libanensis also had a higher log10 reduction than Gram positive Staphylococcus epidermidis. Mixed species biofilms of P. aeruginosa and S. epidermidis showed a similar trend of Gram positive bacteria being more resistant to CAP treatment. However, when grown in co-culture, Gram negative P. aeruginosa was more resistant to CAP overall than as a mono-species biofilm. Emission spectra indicated OH and O, capable of structural cell wall bond breakage, were present in the plasma. This study indicates that cell wall thickness correlates with CAP inactivation times of bacteria, but cell membranes and biofilm matrix are also likely to play a role.

  1. Molecular evolution of the nif gene cluster carrying nifI1 and nifI2 genes in the Gram-positive phototrophic bacterium Heliobacterium chlorum.

    Science.gov (United States)

    Enkh-Amgalan, Jigjiddorj; Kawasaki, Hiroko; Seki, Tatsuji

    2006-01-01

    A major nif cluster was detected in the strictly anaerobic, Gram-positive phototrophic bacterium Heliobacterium chlorum. The cluster consisted of 11 genes arranged within a 10 kb region in the order nifI1, nifI2, nifH, nifD, nifK, nifE, nifN, nifX, fdx, nifB and nifV. The phylogenetic position of Hbt. chlorum was the same in the NifH, NifD, NifK, NifE and NifN trees; Hbt. chlorum formed a cluster with Desulfitobacterium hafniense, the closest neighbour of heliobacteria based on the 16S rRNA phylogeny, and two species of the genus Geobacter belonging to the Deltaproteobacteria. Two nifI genes, known to occur in the nif clusters of methanogenic archaea between nifH and nifD, were found upstream of the nifH gene of Hbt. chlorum. The organization of the nif operon and the phylogeny of individual and concatenated gene products showed that the Hbt. chlorum nif operon carrying nifI genes upstream of the nifH gene was an intermediate between the nif operon with nifI downstream of nifH (group II and III of the nitrogenase classification) and the nif operon lacking nifI (group I). Thus, the phylogenetic position of Hbt. chlorum nitrogenase may reflect an evolutionary stage of a divergence of the two nitrogenase groups, with group I consisting of the aerobic diazotrophs and group II consisting of strictly anaerobic prokaryotes.

  2. Comparative analysis of uranium bioassociation with halophilic bacteria and archaea

    Science.gov (United States)

    Bader, Miriam; Müller, Katharina; Foerstendorf, Harald; Schmidt, Matthias; Simmons, Karen; Swanson, Juliet S.; Reed, Donald T.; Stumpf, Thorsten

    2018-01-01

    Rock salt represents a potential host rock formation for the final disposal of radioactive waste. The interactions between indigenous microorganisms and radionuclides, e.g. uranium, need to be investigated to better predict the influence of microorganisms on the safety assessment of the repository. Hence, the association process of uranium with two microorganisms isolated from rock salt was comparatively studied. Brachybacterium sp. G1, which was isolated from the German salt dome Gorleben, and Halobacterium noricense DSM15987T, were selected as examples of a moderately halophilic bacterium and an extremely halophilic archaeon, respectively. The microorganisms exhibited completely different association behaviors with uranium. While a pure biosorption process took place with Brachybacterium sp. G1 cells, a multistage association process occurred with the archaeon. In addition to batch experiments, in situ attenuated total reflection Fourier-transform infrared spectroscopy was applied to characterize the U(VI) interaction process. Biosorption was identified as the dominating process for Brachybacterium sp. G1 with this method. Carboxylic functionalities are the dominant interacting groups for the bacterium, whereas phosphoryl groups are also involved in U(VI) association by the archaeon H. noricense. PMID:29329319

  3. Characterization of the promising poly(3-hydroxybutyrate) producing halophilic bacterium Halomonas halophila

    Czech Academy of Sciences Publication Activity Database

    Kučera, D.; Pernicová, I.; Kovalčik, A.; Koller, M.; Müllerová, L.; Sedláček, P.; Mravec, F.; Nebesářová, Jana; Kalina, M.; Márová, I.; Krzyžánek, Vladislav; Obruča, S.

    2018-01-01

    Roč. 256, May (2018), s. 552-556 ISSN 0960-8524 R&D Projects: GA MŠk(CZ) LM2015062; GA ČR(CZ) GA15-20645S Institutional support: RVO:68081731 Keywords : Halomonas halophila * halophiles * lignocellulose hydrolysates * morphology of bacterial cells * polyhydroxyalkanoates Impact factor: 5.651, year: 2016

  4. Distribution of multi-resistant Gram-negative versus Gram-positive bacteria in the hospital inanimate environment.

    Science.gov (United States)

    Lemmen, S W; Häfner, H; Zolldann, D; Stanzel, S; Lütticken, R

    2004-03-01

    We prospectively studied the difference in detection rates of multi-resistant Gram-positive and multi-resistant Gram-negative bacteria in the inanimate environment of patients harbouring these organisms. Up to 20 different locations around 190 patients were surveyed. Fifty-four patients were infected or colonized with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE) and 136 with multi-resistant Gram-negative bacteria. The environmental detection rate for MRSA or VRE was 24.7% (174/705 samples) compared with 4.9% (89/1827 samples) for multi-resistant Gram-negative bacteria (PGram-positive bacteria were isolated more frequently than Gram-negatives from the hands of patients (PGram-positive and Gram-negative isolates. Our results suggest that the inanimate environment serves as a secondary source for MRSA and VRE, but less so for Gram-negative bacteria. Thus, strict contact isolation in a single room with complete barrier precautions is recommended for MRSA or VRE; however, for multi-resistant Gram-negative bacteria, contact isolation with barrier precautions for close contact but without a single room seems sufficient. This benefits not only the patients, but also the hospital by removing some of the strain placed on already over-stretched resources.

  5. Evaluation of Inhibitory and Lethal Effects of Aqueous, Ethanolic and Hydroalcoholic Extracts of Aerial Parts of Salvia chorassanica against Some Gram-negative and Gram-positive Bacteria in Vitro

    Directory of Open Access Journals (Sweden)

    Azam Mehraban

    2016-05-01

    Full Text Available Abstract Background and Objectives: Development of bacterial resistance to antibiotics has led to an increased tendency to development of new more effective and non-toxic antimicrobial compounds. In this study, the inhibitory and lethal effects of aqueous, ethanolic, and hydroalcoholic extracts of aerial parts of Salvia chorassanica were evaluated against Listeria monocytogenes, Bacillus cereus, Salmonella typhi, and Escherichia coli O:157. Methods: In this study, Kirby–Bauer disk diffusion method was used to evaluate antimicrobial activity. In this method, bacteria were cultivated as grass culture in Mueller Hinton Agar (MHA media. To determine the minimum inhibitory concentration and minimum bactericidal concentration, micro-dilution method with ELISA and addition of phenyl tetrazolium chloride reagent, were used. Data were analyzed using one-way ANOVA and Duncan’s test at the significance level of p<0.05. Results: The highest diameter of inhibition in agar diffusion method was related to hydroalcoholic extract of aerial parts of Salvia chorassanica against Gram-positive bacteria Bacillus cereus. The amount of calculated MIC of hydro-alcoholic extract for Gram-positive bacteria was 30mg/ml. This amount was the lowest among other measured MIC. Conclusion: Based on the results of this study, Gram-negative bacteria showed more resistance to different extracts of aerial parts of Salvia chorassanica as compared to Gram-positive bacteria, so that Salmonella typhi was found to be the most resistant bacterium among the tested bacteria.

  6. An optimized staining technique for the detection of Gram positive and Gram negative bacteria within tissue.

    Science.gov (United States)

    Becerra, Sandra C; Roy, Daniel C; Sanchez, Carlos J; Christy, Robert J; Burmeister, David M

    2016-04-12

    Bacterial infections are a common clinical problem in both acute and chronic wounds. With growing concerns over antibiotic resistance, treatment of bacterial infections should only occur after positive diagnosis. Currently, diagnosis is delayed due to lengthy culturing methods which may also fail to identify the presence of bacteria. While newer costly bacterial identification methods are being explored, a simple and inexpensive diagnostic tool would aid in immediate and accurate treatments for bacterial infections. Histologically, hematoxylin and eosin (H&E) and Gram stains have been employed, but are far from optimal when analyzing tissue samples due to non-specific staining. The goal of the current study was to develop a modification of the Gram stain that enhances the contrast between bacteria and host tissue. A modified Gram stain was developed and tested as an alternative to Gram stain that improves the contrast between Gram positive bacteria, Gram negative bacteria and host tissue. Initially, clinically relevant strains of Pseudomonas aeruginosa and Staphylococcus aureus were visualized in vitro and in biopsies of infected, porcine burns using routine Gram stain, and immunohistochemistry techniques involving bacterial strain-specific fluorescent antibodies as validation tools. H&E and Gram stain of serial biopsy sections were then compared to a modification of the Gram stain incorporating a counterstain that highlights collagen found in tissue. The modified Gram stain clearly identified both Gram positive and Gram negative bacteria, and when compared to H&E or Gram stain alone provided excellent contrast between bacteria and non-viable burn eschar. Moreover, when applied to surgical biopsies from patients that underwent burn debridement this technique was able to clearly detect bacterial morphology within host tissue. We describe a modification of the Gram stain that provides improved contrast of Gram positive and Gram negative microorganisms within host

  7. Partial characterization of an extracellular polysaccharide produced by the moderately halophilic bacterium Halomonas xianhensis SUR308.

    Science.gov (United States)

    Biswas, Jhuma; Ganguly, J; Paul, A K

    2015-01-01

    A moderately halophilic bacterium, Halomonas xianhensis SUR308 (Genbank Accession No. KJ933394) was isolated from a multi-pond solar saltern at Surala, Ganjam district, Odisha, India. The isolate produced a significant amount (7.87 g l(-1)) of extracellular polysaccharides (EPS) when grown in malt extract-yeast extract medium supplemented with 2.5% NaCl, 0.5% casein hydrolysate and 3% glucose. The EPS was isolated and purified following the conventional method of precipitation and dialysis. Chromatographic analysis (paper, GC and GC-MS) of the hydrolyzed EPS confirmed its heteropolymeric nature and showed that it is composed mainly of glucose (45.74 mol%), galactose (33.67 mol %) and mannose (17.83 mol%). Fourier-transform infrared spectroscopy indicated the presence of methylene and carboxyl groups as characteristic functional groups. In addition, its proton nuclear magnetic resonance spectrum revealed functional groups specific for extracellular polysaccharides. X-ray diffraction analysis revealed the amorphous nature (CIxrd, 0.56) of the EPS. It was thermostable up to 250 °C and displayed pseudoplastic rheology and remarkable stability against pH and salts. These unique properties of the EPS produced by H. xianhensis indicate its potential to act as an agent for detoxification, emulsification and diverse biological activities.

  8. Selection of halophilic bacteria for biological control of tomato gray mould caused by Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Imane BERRADA

    2013-01-01

    Full Text Available In Morocco, tomato gray mould caused by Botrytis cinerea Pers: Fr. is a serious threat for postharvest storage of tomatoes. Fifteen halophilic bacteria were evaluated for their antagonistic activity against B. cinerea: 11 Gram positive strains assigned to the genera Bacillus (9, Jeotgalibacillus (1 and Planococcus (1 and four Gram negative strains assigned to the genera Salinivibrio (1, Vibrio (2 and Photobacterium (1. In in vitro screening, 12 antifungal isolates secreted diffusible compounds, hydrolytic enzymes or volatile compounds. In vivo screening of the isolates, Bacillus safensis CCMM B582 and Bacillus oceanisediminis CCMM B584 showed permanent antagonistic activity on tomato fruits, with 100% inhibition of B. cinerea after 7 days. These two strains may offer potential for biological control of tomato gray mould.

  9. The Toll pathway underlies host sexual dimorphism in resistance to both Gram-negative and Gram-positive bacteria in mated Drosophila.

    Science.gov (United States)

    Duneau, David F; Kondolf, Hannah C; Im, Joo Hyun; Ortiz, Gerardo A; Chow, Christopher; Fox, Michael A; Eugénio, Ana T; Revah, J; Buchon, Nicolas; Lazzaro, Brian P

    2017-12-21

    Host sexual dimorphism is being increasingly recognized to generate strong differences in the outcome of infectious disease, but the mechanisms underlying immunological differences between males and females remain poorly characterized. Here, we used Drosophila melanogaster to assess and dissect sexual dimorphism in the innate response to systemic bacterial infection. We demonstrated sexual dimorphism in susceptibility to infection by a broad spectrum of Gram-positive and Gram-negative bacteria. We found that both virgin and mated females are more susceptible than mated males to most, but not all, infections. We investigated in more detail the lower resistance of females to infection with Providencia rettgeri, a Gram-negative bacterium that naturally infects D. melanogaster. We found that females have a higher number of phagocytes than males and that ablation of hemocytes does not eliminate the dimorphism in resistance to P. rettgeri, so the observed dimorphism does not stem from differences in the cellular response. The Imd pathway is critical for the production of antimicrobial peptides in response to Gram-negative bacteria, but mutants for Imd signaling continued to exhibit dimorphism even though both sexes showed strongly reduced resistance. Instead, we found that the Toll pathway is responsible for the dimorphism in resistance. The Toll pathway is dimorphic in genome-wide constitutive gene expression and in induced response to infection. Toll signaling is dimorphic in both constitutive signaling and in induced activation in response to P. rettgeri infection. The dimorphism in pathway activation can be specifically attributed to Persephone-mediated immune stimulation, by which the Toll pathway is triggered in response to pathogen-derived virulence factors. We additionally found that, in absence of Toll signaling, males become more susceptible than females to the Gram-positive Enterococcus faecalis. This reversal in susceptibility between male and female Toll

  10. Isolation and initial characterization of the tellurite reducing moderately halophilic bacterium, Salinicoccus sp. strain QW6.

    Science.gov (United States)

    Amoozegar, Mohammad Ali; Ashengroph, Morahem; Malekzadeh, Feridon; Reza Razavi, Mohamad; Naddaf, Saied; Kabiri, Mahboubeh

    2008-01-01

    Among the 49 strains of moderately halophilic bacteria isolated from the salty environments of Iran, a Gram-positive coccus designated as strain QW6 showed high capacity in the removal of toxic oxyanions of tellurium in a wide range of culture medium factors including pH (5.5-10.5), temperature (25-45 degrees C), various salts including NaCl, KCl, and Na(2)SO(4) (0.5-4 M), selenooxyanions (2-10 mM), and at different concentrations of potassium tellurite (0.5-1 mM) under aerobic condition. Phenotypic characterization and phylogenetic analyses based on 16S rDNA sequence comparisons indicated that this strain was a member of the genus Salinicoccus. The maximum tellurite removal was exhibited in 1.5M NaCl at 35 degrees C, while the activity reduced by 53% and 47% at 25 and 45 degrees C, respectively. The optimum pH for removal activity was shown to be 7.5, with 90% and 83% reduced removal capacities at the two extreme values of 5.5 and 10, respectively. The impact of different concentrations of selenooxyanions (2-10 mM) on tellurite removal by strain QW6 was evaluated. The ability of strain QW6 in the removal of tellurite in the presence of 6mM selenite increased by 25%. The concentration of toxic potassium tellurite in the supernatant of the bacterial culture medium decreased by 99% (from 0.5 to 0.005 mM) after 6 days and the color of the medium changed to black due to the formation of less toxic elemental tellurium.

  11. Glass bead transformation method for gram-positive bacteria

    OpenAIRE

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2009-01-01

    A simple, inexpensive and reproducible transformation method was developed for Gram-positive bacteria. It was based on agitation of bacterial protoplasts with glass beads in the presence of DNA and polyethylene glycol. By using this method, introduction of pGK12 into protoplasts of several strains of Gram-positive bacteria was achieved.

  12. Comparative activity of ceftobiprole against Gram-positive and Gram-negative isolates from Europe and the Middle East: the CLASS study.

    Science.gov (United States)

    Rossolini, Gian M; Dryden, Matthew S; Kozlov, Roman S; Quintana, Alvaro; Flamm, Robert K; Läuffer, Jörg M; Lee, Emma; Morrissey, Ian; CLASS Study Group

    2011-01-01

    to assess the in vitro activity of ceftobiprole and comparators against a recent collection of Gram-positive and Gram-negative pathogens, in order to detect potential changes in susceptibility patterns, and to evaluate the Etest assay for ceftobiprole susceptibility testing. contemporary Gram-positive and Gram-negative isolates (excluding extended-spectrum β-lactamase-producing isolates) from across Europe and the Middle East were collected, and their susceptibility to ceftobiprole, vancomycin, teicoplanin, linezolid, ceftazidime and cefepime was assessed using the Etest method. Quality testing [using Etest and broth microdilution (BMD)] was conducted at a central reference laboratory. some 5041 Gram-positive and 4026 Gram-negative isolates were included. Against Gram-positive isolates overall, ceftobiprole had the lowest MIC50 (0.5 mg/L), compared with 1 mg/L for its comparators (vancomycin, teicoplanin and linezolid). Against methicillin-resistant Staphylococcus aureus, all four agents had a similar MIC90 (2 mg/L), but ceftobiprole had a 4-fold better MIC90 (0.5 mg/L) against methicillin-susceptible strains. Only 38 Gram-positive isolates were confirmed as ceftobiprole resistant. Among Gram-negative strains, 86.9%, 91.7% and 95.2% were susceptible to ceftobiprole, ceftazidime and cefepime, respectively. Pseudomonas aeruginosa was less susceptible to all three antimicrobials than any other Gram-negative pathogen. There was generally good agreement between local Etest results and those obtained at the reference laboratory (for ceftobiprole: 86.8% with Gram-negatives; and 94.7% with Gram-positives), as well as between results obtained by BMD and Etest methods (for ceftobiprole: 98.2% with Gram-negatives; and 98.4% with Gram-positives). ceftobiprole exhibits in vitro activity against a wide range of Gram-positive and Gram-negative pathogens, including multidrug-resistant strains. No changes in its known susceptibility profile were identified.

  13. Prognostic factors and monomicrobial necrotizing fasciitis: gram-positive versus gram-negative pathogens

    Directory of Open Access Journals (Sweden)

    Hsu Wei-Hsiu

    2011-01-01

    Full Text Available Abstract Background Monomicrobial necrotizing fasciitis is rapidly progressive and life-threatening. This study was undertaken to ascertain whether the clinical presentation and outcome for patients with this disease differ for those infected with a gram-positive as compared to gram-negative pathogen. Methods Forty-six patients with monomicrobial necrotizing fasciitis were examined retrospectively from November 2002 to January 2008. All patients received adequate broad-spectrum antibiotic therapy, aggressive resuscitation, prompt radical debridement and adjuvant hyperbaric oxygen therapy. Eleven patients were infected with a gram-positive pathogen (Group 1 and 35 patients with a gram-negative pathogen (Group 2. Results Group 2 was characterized by a higher incidence of hemorrhagic bullae and septic shock, higher APACHE II scores at 24 h post-admission, a higher rate of thrombocytopenia, and a higher prevalence of chronic liver dysfunction. Gouty arthritis was more prevalent in Group 1. For non-survivors, the incidences of chronic liver dysfunction, chronic renal failure and thrombocytopenia were higher in comparison with those for survivors. Lower level of serum albumin was also demonstrated in the non-survivors as compared to those in survivors. Conclusions Pre-existing chronic liver dysfunction, chronic renal failure, thrombocytopenia and hypoalbuminemia, and post-operative dependence on mechanical ventilation represent poor prognostic factors in monomicrobial necrotizing fasciitis. Patients with gram-negative monobacterial necrotizing fasciitis present with more fulminant sepsis.

  14. Protamine-induced permeabilization of cell envelopes of gram-positive and gram-negative bacteria

    DEFF Research Database (Denmark)

    Johansen, Charlotte; Verheul, A.; Gram, Lone

    1997-01-01

    carboxyfluorescein and ATP after 2 to 5 min. Maximum antibacterial activity was reached at alkaline pH and in the absence of divalent cations. The efficient permeabilization of cell envelopes of both gram-positive and gram-negative bacteria suggests that protamine causes a general disruption of the cell envelope...

  15. Marinospirillum insulare sp. nov., a novel halophilic helical bacterium isolated from kusaya gravy.

    Science.gov (United States)

    Satomi, M; Kimura, B; Hayashi, M; Okuzumi, M; Fujii, T

    2004-01-01

    A novel species that belongs to the genus Marinospirillum is described on the basis of phenotypic characteristics, phylogenetic analysis of 16S rRNA and gyrB gene sequences and DNA-DNA hybridization. Four strains of helical, halophilic, Gram-negative, heterotrophic bacteria were isolated from kusaya gravy, which is fermented brine that is used for the production of traditional dried fish in the Izu Islands of Japan. All of the new isolates were motile by means of bipolar tuft flagella, of small cell size, coccoid-body-forming and aerophilic; it was concluded that they belong to the same bacterial species, based on DNA-DNA hybridization values (>70% DNA relatedness). DNA G+C contents of the new strains were 42-43 mol% and they had isoprenoid quinone Q-8 as the major component. Phylogenetic analysis of 16S rRNA gene sequences indicated that the new isolates were members of the genus Marinospirillum; sequence similarity of the new isolates to Marinospirillum minutulum, Marinospirillum megaterium and Marinospirillum alkaliphilum was 98.5, 98.2 and 95.2%, respectively. Phylogenetic analysis based on the gyrB gene indicated that the new isolates had enough phylogenetic distance from M. minutulum and M. megaterium to be regarded as different species, with 84.7 and 78.7% sequence similarity, respectively. DNA-DNA hybridization showed that the new isolates had <36% DNA relatedness to M. minutulum and M. megaterium, supporting the phylogenetic conclusion. Thus, a novel species is proposed: Marinospirillum insulare sp. nov. (type strain, KT=LMG 21802T=NBRC 100033T).

  16. Defining a role for Hfq in Gram-positive bacteria

    DEFF Research Database (Denmark)

    Nielsen, Jesper Sejrup; Lei, Lisbeth Kristensen; Ebersbach, Tine

    2010-01-01

    Small trans-encoded RNAs (sRNAs) modulate the translation and decay of mRNAs in bacteria. In Gram-negative species, antisense regulation by trans-encoded sRNAs relies on the Sm-like protein Hfq. In contrast to this, Hfq is dispensable for sRNA-mediated riboregulation in the Gram-positive species......-dependent and -independent mechanisms, thus adding another layer of complexity to sRNA-mediated riboregulation in Gram-positive species....

  17. Biosynthesis and characterization of polyhydroxyalkanoates produced by an extreme halophilic bacterium, Halomonas nitroreducens, isolated from hypersaline ponds.

    Science.gov (United States)

    Cervantes-Uc, J M; Catzin, J; Vargas, I; Herrera-Kao, W; Moguel, F; Ramirez, E; Rincón-Arriaga, S; Lizama-Uc, G

    2014-10-01

    Morphological, biochemical and genotypic characterization of a halophilic bacterium isolated from hypersaline ponds located at Las Coloradas (Río Lagartos, Yucatán, Mexico). Characterization of polymer produced by this strain was also performed. Twenty strains were isolated from water samples of salt ponds and selected based on both morphological features and their PHA storage capacity, which were determined by SEM and staining methods with Nile red and Nile blue, respectively; strains were also analysed by the fluorescence imaging technique. Among them, JCCOL25.8 strain showed the highest production of PHA's reason why phenotypic and genotypic characterization was performed; this strain was identified as Halomonas nitroreducens. Polymer produced by this strain was characterized by FTIR, DSC, GPC and EDX spectroscopy. Results indicated that the biosynthesized polymer was polyhydroxybutyrate (PHB) which had a melting peak at 170°C and a crystallinity percentage of about 36%. Based on phenotypic and genotypic aspects, JCCOL25.8 strain was identified as H. nitroreducens and it was capable to accumulate PHB. To our knowledge, there is only one study published on the biosynthesis of PHA's by H. nitroreducens strains, although the characterization of the obtained polymer was not reported. © 2014 The Society for Applied Microbiology.

  18. Antiadhesion agents against Gram-positive pathogens.

    Science.gov (United States)

    Cascioferro, Stella; Cusimano, Maria Grazia; Schillaci, Domenico

    2014-01-01

    A fundamental step of Gram-positive pathogenesis is the bacterial adhesion to the host tissue involving interaction between bacterial surface molecules and host ligands. This review is focused on antivirulence compounds that target Gram-positive adhesins and on their potential development as therapeutic agents alternative or complementary to conventional antibiotics in the contrast of pathogens. In particular, compounds that target the sortase A, wall theicoic acid inhibitors, carbohydrates able to bind bacterial proteins and proteins capable of influencing the bacterial adhesion, were described. We further discuss the advantages and disadvantages of this strategy in the development of novel antimicrobials and the future perspective of this research field still at its first steps.

  19. An efficient thermotolerant and halophilic biosurfactant-producing bacterium isolated from Dagang oil field for MEOR application

    Science.gov (United States)

    Wu, Langping; Richnow, Hans; Yao, Jun; Jain, Anil

    2014-05-01

    Dagang Oil field (Petro China Company Limited) is one of the most productive oil fields in China. In this study, 34 biosurfactant-producing strains were isolated and cultured from petroleum reservoir of Dagang oil field, using haemolytic assay and the qualitative oil-displacement test. On the basis of 16S rDNA analysis, the isolates were closely related to the species in genus Pseudomonas, Staphylococcus and Bacillus. One of the isolates identified as Bacillus subtilis BS2 were selected for further study. This bacterium was able to produce a type of biosurfactant with excessive foam-forming properties at 37ºC as well as at higher temperature of 55ºC. The biosurfactant produced by the strain BS2 could reduce the surface tension of the culture broth from 70.87 mN/m to 28.97 mN/m after 8 days of incubation at 37ºC and to 36.15 mN/m after 20 days of incubation at 55ºC, respectively. The biosurfactant showed stability at high temperature (up to 120ºC), a wide range of pH (2 to 12) and salt concentrations (up to 12%) offering potential for biotechnology. Fourier transform infrared (FT-IR) spectrum of extracted biosurfactant tentatively characterized the produced biosurfactant as glycolipid derivative. Elemental analysis of the biosurfactant by energy dispersive X-ray spectroscopy (EDS) reveals that the biosurfactant was anionic in nature. 15 days of biodegradation of crude oil suggested a preferential usage of n-alkane upon microbial metabolism of BS2 as a carbon substrate and consequently also for the synthesis of biosurfactants. Core flood studies for oil release indicated 9.6% of additional oil recovery over water flooding at 37ºC and 7.2% of additional oil recovery at 55 ºC. Strain BS2 was characterized as an efficient biosurfactant-producing, thermotolerant and halophillic bacterium and has the potential for application for microbial enhanced oil recovery (MEOR) through water flooding in China's oil fields even in situ as adapted to reservoir chemistry and

  20. Gram-positive bacteria persisting in the food production environment

    DEFF Research Database (Denmark)

    Knøchel, Susanne; Harmsen, Morten; Knudsen, Bettina

    2008-01-01

    Many gram-positive bacteria are able to form aggregates or biofilms and resist external stress factors and some gram-positive pathogenic bacteria such as Listeria monocytogenes and Bacillus cereus may persist in the food production environment for extended periods. Most research has focussed...

  1. Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

    International Nuclear Information System (INIS)

    Varghese, S.; Jose, S.; Varghese, S.; Kuriakose, S.; Jose, S.

    2013-01-01

    This paper describes the isolation of carbon nanoparticles (CNPs) from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains

  2. Halophilic & halotolerant prokaryotes in humans.

    Science.gov (United States)

    Seck, El Hadji; Dufour, Jean-Charles; Raoult, Didier; Lagier, Jean-Christophe

    2018-05-04

    Halophilic prokaryotes are described as microorganisms living in hypersaline environments. Here, we list the halotolerant and halophilic bacteria which have been isolated in humans. Of the 52 halophilic prokaryotes, 32 (61.54%) were moderately halophilic, 17 (32.69%) were slightly halophilic and three (5.76%) were extremely halophilic prokaryotes. At the phylum level, 29 (54.72%) belong to Firmicutes, 15 (28.84%) to Proteobacteria, four (7.69%) to Actinobacteria, three (5.78%) to Euryarchaeota and one (1.92%) belongs to Bacteroidetes. Halophilic prokaryotes are rarely pathogenic: of these 52 halophilic prokaryotes only two (3.92%) species were classified in Risk Group 2 (Vibrio cholerae, Vibrio parahaemolyticus) and one (1.96%), species in Risk Group 3 (Bacillus anthracis).

  3. Structural changes in halophilic and non-halophilic proteases in response to chaotropic reagents.

    Science.gov (United States)

    Sinha, Rajeshwari; Khare, S K

    2014-08-01

    Halophilic enzymes have been established for their stability and catalytic abilities under harsh operational conditions. These have been documented to withstand denaturation at high temperature, pH, organic solvents, and chaotropic agents. However, this stability is modulated by salt. The present study targets an important aspect in understanding protein-urea/GdmCl interactions using proteases from halophilic Bacillus sp. EMB9 and non-halophilic subtilisin (Carlsberg) from Bacillus licheniformis as model systems. While, halophilic protease containing 1 % (w/v) NaCl (0.17 M) retained full activity towards urea (8 M), non-halophilic protease lost about 90 % activity under similar conditions. The secondary and tertiary structure were lost in non-halophilic but preserved for halophilic protein. This effect could be due to the possible charge screening and shielding of the protein surface by Ca(2+) and Na(+) ions rendering it stable against denaturation. The dialyzed halophilic protease almost behaved like the non-halophilic counterpart. Incorporation of NaCl (up to 5 %, w/v or 0.85 M) in dialyzed EMB9 protease containing urea/GdmCl, not only helped regain of proteolytic activity but also evaded denaturing action. Deciphering the basis of this salt modulated stability amidst a denaturing milieu will provide guidelines and templates for engineering stable proteins/enzymes for biotechnological applications.

  4. Gram-positive rods prevailing in teeth with apical periodontitis undergoing root canal treatment.

    Science.gov (United States)

    Chávez de Paz, L E; Molander, A; Dahlén, G

    2004-09-01

    To identify Gram-positive rods from root canals of teeth with apical periodontitis and to examine their associations with other species. Consecutive root canal samples (RCSs) from 139 teeth undergoing root canal treatment were analyzed prospectively for cultivable microbes. Gram-positive rods in the first RCS submitted after chemo-mechanical preparation were categorised to genus level by selective media and gas-liquid chromatography (GLC), and identified to species level by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Associations between organisms were measured by odds ratios (OR). In the first samples submitted a total of 158 Gram-positive rods, 115 Gram-positive cocci, 26 Gram-negative rods and 9 Gram-negative cocci, were identified. At genus levels Gram-positive rods were classified into: Lactobacillus spp. (38%), Olsenella spp. (18%), Propionibacterium spp. (13%), Actinomyces spp. (12%), Bifidobacterium spp. (13%) and Eubacterium spp. (6%). The most frequent species were Olsenella uli, Lactobacillus paracasei and Propionibacterium propionicum. In subsequent samples taken during treatment, Gram-positive rods were also identified, although the number of strains was considerably reduced. Positive associations were observed between members of the genus lactobacilli and Gram-positive cocci (OR>2). Olsenella uli and Lactobacillus spp. predominated over other Gram-positive rods. A possible association exists between Lactobacillus spp. and Gram-positive cocci in root canals of teeth with apical periodontitis receiving treatment.

  5. Unique Features of Halophilic Proteins.

    Science.gov (United States)

    Arakawa, Tsutomu; Yamaguchi, Rui; Tokunaga, Hiroko; Tokunaga, Masao

    2017-01-01

    Proteins from moderate and extreme halophiles have unique characteristics. They are highly acidic and hydrophilic, similar to intrinsically disordered proteins. These characteristics make the halophilic proteins soluble in water and fold reversibly. In addition to reversible folding, the rate of refolding of halophilic proteins from denatured structure is generally slow, often taking several days, for example, for extremely halophilic proteins. This slow folding rate makes the halophilic proteins a novel model system for folding mechanism analysis. High solubility and reversible folding also make the halophilic proteins excellent fusion partners for soluble expression of recombinant proteins.

  6. Selenoproteins in Archaea and Gram-positive bacteria.

    Science.gov (United States)

    Stock, Tilmann; Rother, Michael

    2009-11-01

    Selenium is an essential trace element for many organisms by serving important catalytic roles in the form of the 21st co-translationally inserted amino acid selenocysteine. It is mostly found in redox-active proteins in members of all three domains of life and analysis of the ever-increasing number of genome sequences has facilitated identification of the encoded selenoproteins. Available data from biochemical, sequence, and structure analyses indicate that Gram-positive bacteria synthesize and incorporate selenocysteine via the same pathway as enterobacteria. However, recent in vivo studies indicate that selenocysteine-decoding is much less stringent in Gram-positive bacteria than in Escherichia coli. For years, knowledge about the pathway of selenocysteine synthesis in Archaea and Eukarya was only fragmentary, but genetic and biochemical studies guided by analysis of genome sequences of Sec-encoding archaea has not only led to the characterization of the pathways but has also shown that they are principally identical. This review summarizes current knowledge about the metabolic pathways of Archaea and Gram-positive bacteria where selenium is involved, about the known selenoproteins, and about the respective pathways employed in selenoprotein synthesis.

  7. Selective bowel decontamination results in gram-positive translocation.

    Science.gov (United States)

    Jackson, R J; Smith, S D; Rowe, M I

    1990-05-01

    Colonization by enteric gram-negative bacteria with subsequent translocation is believed to be a major mechanism for infection in the critically ill patient. Selective bowel decontamination (SBD) has been used to control gram-negative infections by eliminating these potentially pathogenic bacteria while preserving anaerobic and other less pathogenic organisms. Infection with gram-positive organisms and anaerobes in two multivisceral transplant patients during SBD led us to investigate the effect of SBD on gut colonization and translocation. Twenty-four rats received enteral polymixin E, tobramycin, amphotericin B, and parenteral cefotaxime for 7 days (PTA + CEF); 23 received parenteral cefotaxime alone (CEF), 19 received the enteral antibiotics alone (PTA), 21 controls received no antibiotics. Cecal homogenates, mesenteric lymph node (MLN), liver, and spleen were cultured. Only 8% of the PTA + CEF group had gram-negative bacteria in cecal culture vs 52% CEF, 84% PTA, and 100% in controls. Log Enterococcal colony counts were higher in the PTA + CEF group (8.0 + 0.9) vs controls (5.4 + 0.4) P less than 0.01. Translocation of Enterococcus to the MLN was significantly increased in the PTA + CEF group (67%) vs controls (0%) P less than 0.01. SBD effectively eliminates gram-negative organisms from the gut in the rat model. Overgrowth and translocation of Enterococcus suggests that infection with gram-positive organisms may be a limitation of SBD.

  8. Insights into the sequence parameters for halophilic adaptation.

    Science.gov (United States)

    Nath, Abhigyan

    2016-03-01

    The sequence parameters for halophilic adaptation are still not fully understood. To understand the molecular basis of protein hypersaline adaptation, a detailed analysis is carried out, and investigated the likely association of protein sequence attributes to halophilic adaptation. A two-stage strategy is implemented, where in the first stage a supervised machine learning classifier is build, giving an overall accuracy of 86 % on stratified tenfold cross validation and 90 % on blind testing set, which are better than the previously reported results. The second stage consists of statistical analysis of sequence features and possible extraction of halophilic molecular signatures. The results of this study showed that, halophilic proteins are characterized by lower average charge, lower K content, and lower S content. A statistically significant preference/avoidance list of sequence parameters is also reported giving insights into the molecular basis of halophilic adaptation. D, Q, E, H, P, T, V are significantly preferred while N, C, I, K, M, F, S are significantly avoided. Among amino acid physicochemical groups, small, polar, charged, acidic and hydrophilic groups are preferred over other groups. The halophilic proteins also showed a preference for higher average flexibility, higher average polarity and avoidance for higher average positive charge, average bulkiness and average hydrophobicity. Some interesting trends observed in dipeptide counts are also reported. Further a systematic statistical comparison is undertaken for gaining insights into the sequence feature distribution in different residue structural states. The current analysis may facilitate the understanding of the mechanism of halophilic adaptation clearer, which can be further used for rational design of halophilic proteins.

  9. Dustborne and airborne gram-positive and gram-negative bacteria in high versus low ERMI homes

    Science.gov (United States)

    The study aimed at investigating Gram-positive and Gram-negative bacteria in moldy and non-moldy homes, as defined by the home's Environmental Relative Moldiness Index (ERMI) value. The ERMI values were determined from floor dust samples in 2010 and 2011 and homes were classified...

  10. Gram-positive and gram-negative bacteria induce different patterns of cytokine production in human mononuclear cells irrespective of taxonomic relatedness.

    Science.gov (United States)

    Skovbjerg, Susann; Martner, Anna; Hynsjö, Lars; Hessle, Christina; Olsen, Ingar; Dewhirst, Floyd E; Tham, Wilhelm; Wold, Agnes E

    2010-01-01

    Upon bacterial stimulation, tissue macrophages produce a variety of cytokines that orchestrate the immune response that clears the infection. We have shown that Gram-positives induce higher levels of interleukin-12 (IL-12), interferon-gamma (IFN-gamma), and tumor necrosis factor (TNF) from human peripheral blood mononuclear cells (PBMCs) than do Gram-negatives, which instead induce more of IL-6, IL-8, and IL-10. Here, we study whether these patterns follows or crosses taxonomic borders. PBMCs from blood donors were incubated with UV-inactivated bacteria representing 37 species from five phyla. IL-12, TNF, IL-1beta, IL-6, IL-8, and IL-10 were measured in the supernatants after 24 h and IFN-gamma after 5 days. Irrespective of phylogenetic position, Gram-positive bacteria induced much more IL-12 (nine times more on average) and IFN-gamma (seven times), more TNF (three times), and slightly more IL-1beta (1.5 times) than did Gram-negatives, which instead induced more IL-6 (1.5 times), IL-8 (1.9 times), and IL-10 (3.3 times) than did Gram-positives. A notable exception was the Gram-positive Listeria monocytogenes, which induced very little IL-12, IFN-gamma, and TNF. The results confirm the fundamental difference in innate immune responses to Gram-positive and Gram-negative bacteria, which crosses taxonomic borders and probably reflects differences in cell wall structure.

  11. Draft genome sequence of the extremely halophilic archaeon Haladaptatus cibarius type strain D43(T) isolated from fermented seafood.

    Science.gov (United States)

    Lee, Hae-Won; Kim, Dae-Won; Lee, Mi-Hwa; Kim, Byung-Yong; Cho, Yong-Joon; Yim, Kyung June; Song, Hye Seon; Rhee, Jin-Kyu; Seo, Myung-Ji; Choi, Hak-Jong; Choi, Jong-Soon; Lee, Dong-Gi; Yoon, Changmann; Nam, Young-Do; Roh, Seong Woon

    2015-01-01

    An extremely halophilic archaeon, Haladaptatus cibarius D43(T), was isolated from traditional Korean salt-rich fermented seafood. Strain D43(T) shows the highest 16S rRNA gene sequence similarity (98.7 %) with Haladaptatus litoreus RO1-28(T), is Gram-negative staining, motile, and extremely halophilic. Despite potential industrial applications of extremely halophilic archaea, their genome characteristics remain obscure. Here, we describe the whole genome sequence and annotated features of strain D43(T). The 3,926,724 bp genome includes 4,092 protein-coding and 57 RNA genes (including 6 rRNA and 49 tRNA genes) with an average G + C content of 57.76 %.

  12. Bioengineered nisin A derivatives with enhanced activity against both Gram positive and Gram negative pathogens.

    Directory of Open Access Journals (Sweden)

    Des Field

    Full Text Available Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G, with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria.

  13. Bioengineered Nisin A Derivatives with Enhanced Activity against Both Gram Positive and Gram Negative Pathogens

    Science.gov (United States)

    Field, Des; Begley, Maire; O’Connor, Paula M.; Daly, Karen M.; Hugenholtz, Floor; Cotter, Paul D.; Hill, Colin; Ross, R. Paul

    2012-01-01

    Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria. PMID:23056510

  14. Discovery of novel cell wall-active compounds using P ywaC, a sensitive reporter of cell wall stress, in the model gram-positive bacterium Bacillus subtilis.

    Science.gov (United States)

    Czarny, T L; Perri, A L; French, S; Brown, E D

    2014-06-01

    The emergence of antibiotic resistance in recent years has radically reduced the clinical efficacy of many antibacterial treatments and now poses a significant threat to public health. One of the earliest studied well-validated targets for antimicrobial discovery is the bacterial cell wall. The essential nature of this pathway, its conservation among bacterial pathogens, and its absence in human biology have made cell wall synthesis an attractive pathway for new antibiotic drug discovery. Herein, we describe a highly sensitive screening methodology for identifying chemical agents that perturb cell wall synthesis, using the model of the Gram-positive bacterium Bacillus subtilis. We report on a cell-based pilot screen of 26,000 small molecules to look for cell wall-active chemicals in real time using an autonomous luminescence gene cluster driven by the promoter of ywaC, which encodes a guanosine tetra(penta)phosphate synthetase that is expressed under cell wall stress. The promoter-reporter system was generally much more sensitive than growth inhibition testing and responded almost exclusively to cell wall-active antibiotics. Follow-up testing of the compounds from the pilot screen with secondary assays to verify the mechanism of action led to the discovery of 9 novel cell wall-active compounds. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  15. Taxonomic characterization of the cellulose-degrading bacterium NCIB 10462

    Energy Technology Data Exchange (ETDEWEB)

    Dees, C.; Ringleberg, D.; Scott, T.C. [Oak Ridge National Lab., TN (United States); Phelps, T. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-06-01

    The gram negative cellulase-producing bacterium NCIB 10462 has been previously named Pseudomonas fluorescens subsp. or var. cellulosa. Since there is renewed interest in cellulose-degrading bacteria for use in bioconversion of cellulose to chemical feed stocks and fuels, we re-examined the characteristics of this microorganism to determine its proper taxonomic characterization and to further define it`s true metabolic potential. Metabolic and physical characterization of NCIB 10462 revealed that this was an alkalophilic, non-fermentative, gram negative, oxidase positive, motile, cellulose-degrading bacterium. The aerobic substrate utilization profile of this bacterium was found to have few characteristics consistent with a classification of P. fluorescens with a very low probability match with the genus Sphingomonas. Total lipid analysis did not reveal that any sphingolipid bases are produced by this bacterium. NCIB 10462 was found to grow best aerobically but also grows well in complex media under reducing conditions. NCIB 10462 grew slowly under full anaerobic conditions on complex media but growth on cellulosic media was found only under aerobic conditions. Total fatty acid analysis (MIDI) of NCIB 10462 failed to group this bacterium with a known pseudomonas species. However, fatty acid analysis of the bacteria when grown at temperatures below 37{degrees}C suggest that the organism is a pseudomonad. Since a predominant characteristic of this bacterium is it`s ability to degrade cellulose, we suggest it be called Pseudomonas cellulosa.

  16. Genome sequence of the moderately halophilic bacterium Salinicoccus carnicancri type strain Crm(T) (= DSM 23852(T)).

    Science.gov (United States)

    Hyun, Dong-Wook; Whon, Tae Woong; Cho, Yong-Joon; Chun, Jongsik; Kim, Min-Soo; Jung, Mi-Ja; Shin, Na-Ri; Kim, Joon-Yong; Kim, Pil Soo; Yun, Ji-Hyun; Lee, Jina; Oh, Sei Joon; Bae, Jin-Woo

    2013-01-01

    Salinicoccus carnicancri Jung et al. 2010 belongs to the genus Salinicoccus in the family Staphylococcaceae. Members of the Salinicoccus are moderately halophilic and originate from various salty environments. The halophilic features of the Salinicoccus suggest their possible uses in biotechnological applications, such as biodegradation and fermented food production. However, the genus Salinicoccus is poorly characterized at the genome level, despite its potential importance. This study presents the draft genome sequence of S. carnicancri strain Crm(T) and its annotation. The 2,673,309 base pair genome contained 2,700 protein-coding genes and 78 RNA genes with an average G+C content of 47.93 mol%. It was notable that the strain carried 72 predicted genes associated with osmoregulation, which suggests the presence of beneficial functions that facilitate growth in high-salt environments.

  17. The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

    Science.gov (United States)

    Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

    2014-01-15

    (23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. ["Candidatus contubernalis alkalaceticum," an obligately syntrophic alkaliphilic bacterium capable of anaerobic acetate oxidation in a coculture with Desulfonatronum cooperativum].

    Science.gov (United States)

    Zhilina, T N; Zavarzina, D G; Kolganova, T V; Turova, T P; Zavarzin, G A

    2005-01-01

    From the silty sediments of the Khadyn soda lake (Tuva), a binary sulfidogenic bacterial association capable of syntrophic acetate oxidation at pH 10.0 was isolated. An obligately syntrophic, gram-positive, spore-forming alkaliphilic rod-shaped bacterium performs acetate oxidation in a syntrophic association with a hydrogenotrophic, alkaliphilic sulfate-reducing bacterium; the latter organism was previously isolated and characterized as the new species Desulfonatronum cooperativum. Other sulfate-reducing bacteria of the genera Desulfonatronum and Desulfonatronovibrio can also act as the hydrogenotrophic partner. Apart from acetate, the syntrophic culture can oxidize ethanol, propanol, isopropanol, serine, fructose, and isobutyric acid. Selective amplification of 16S rRNA gene fragments of the acetate-utilizing syntrophic component of the binary culture was performed; it was found to cluster with clones of uncultured gram-positive bacteria within the family Syntrophomonadaceae. The acetate-oxidizing bacterium is thus the first representative of this cluster obtained in a laboratory culture. Based on its phylogenetic position, the new acetate-oxidizing syntrophic bacterium is proposed to be assigned, in a Candidate status, to a new genus and species: "Candidatus Contubernalis alkalaceticum."

  19. Neptunium (V) Adsorption to a Halophilic Bacterium Under High Ionic Strength Conditions: A Surface Complexation Modeling Approach

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory

    2012-06-11

    Rationale for experimental design: Np(V) -- important as analog for Pu(V) and for HLW scenarios; High ionic strength -- relevant to salt-based repositories such as the WIPP; Halophilic microorganisms -- representative of high ionic strength environments. For the first time showed: Significant adsorbant to halophilic microorganisms over entire pH range under high ionic strength conditions; Strong influence of ionic strength with increasing adsorption with increasing ionic strength (in contrast to trends of previous low ionic strength studies); Effect of aqueous Np(V) and bacterial surface site speciation on adsorption; and Developed thermodynamic models that can be incorporated into geochemical speciation models to aid in the prediction of the fate and transport of Np(V) in more complex systems.

  20. Bacillus marismortui sp. nov., a new moderately halophilic species from the Dead Sea.

    Science.gov (United States)

    Arahal, D R; Márquez, M C; Volcani, B E; Schleifer, K H; Ventosa, A

    1999-04-01

    A group of 91 moderately halophilic, Gram-positive, rod-shaped strains were isolated from enrichments prepared from Dead Sea water samples collected 57 years ago. These strains were examined for 117 morphological, physiological, biochemical, nutritional and antibiotic susceptibility characteristics. All strains formed endospores and were motile, strictly aerobic and positive for catalase and oxidase. They grew in media containing 5-25% (w/v) total salts, showing optimal growth at 10% (w/v). Eighteen strains were chosen as representative isolates and were studied in more detail. All these strains had mesodiaminopimelic acid in the cell wall and a DNA G + C content of 39.0-42.8 mol%; they constitute a group with levels of DNA-DNA similarity of 70-100%. The sequences of the 16S rRNA genes of three representative strains (strains 123T, 557 and 832) were almost identical (99.9%), and placed the strains in the low G + C content Gram-positive bacteria. On the basis of their features, these isolates should be regarded as members of a new species of the genus Bacillus, for which the name Bacillus marismortui sp. nov. is proposed. The type strain is strain 123T (= DSM 12325T = ATCC 700626T = CIP 105609T = CECT 5066T).

  1. Antibacterial Activity of Silver-Graphene Quantum Dots Nanocomposites Against Gram-Positive and Gram-Negative Bacteria

    Science.gov (United States)

    Habiba, Khaled (Inventor); Makarov, Vladimir (Inventor); Weiner, Brad R (Inventor); Morell, Gerardo (Inventor)

    2018-01-01

    The invention provides a composite of silver nanoparticles decorated with graphene quantum dots (Ag-GQDs) using pulsed laser synthesis. The nanocomposites were functionalized with polyethylene glycol (PEG). A concentration of 150 .mu.g/mL of Ag-GQDs, a non-toxic level for human cells, exhibits strong antibacterial activity against both Gram-Positive and Gram-Negative Bacteria.

  2. Description of a bacterium associated with redmouth disease of rainbow trout (Salmo gairdneri)

    Science.gov (United States)

    Ross, A.J.; Rucker, R.R.; Ewing, W.H.

    1966-01-01

    A description was given of a gram-negative, peritrichously flagellated, fermentative bacterium that was isolated on numerous occasions from kidney tissues of rainbow trout (Salmo gairdneri) afflicted with redmouth disease. Although the bacteria apparently were members of the family Enterobacteriaceae, it was impossible to determine their taxonomic position within the family with certainty. Hence it was recommended that their taxonomic position remain sub judice for the present. As a temporary designation RM bacterium was used. Redmouth disease was transmitted from infected to normal fish through the medium of water.

  3. Actinopolyspora biskrensis sp. nov., a novel halophilic actinomycete isolated from Northern Sahara.

    Science.gov (United States)

    Saker, Rafika; Bouras, Noureddine; Meklat, Atika; Zitouni, Abdelghani; Schumann, Peter; Spröer, Cathrin; Klenk, Hans-Peter; Sabaou, Nasserdine

    2015-03-01

    A novel halophilic, filamentous actinomycete, designated H254(T), was isolated from a Saharan soil sample collected from Biskra (Northern Sahara), and subjected to a polyphasic taxonomic characterization. The strain is Gram-positive, aerobic, and halophilic, and the optimum NaCl concentration for growth is 15-20 % (w/v). The cell-wall hydrolysate contained meso-diaminopimelic acid, and the diagnostic whole-cell sugars were arabinose and galactose. The diagnostic phospholipid detected was phosphatidylcholine, and MK-9(H4) was the predominant menaquinone. The major fatty acid profiles were anteiso-C17:0 (32.8 %), C15:0 (28 %), and iso-C17:0 (12.3 %). Comparative analysis of the 16S rRNA gene sequences revealed that the strain H254(T) formed a well-separated sub-branch within the radiation of the genus Actinopolyspora, and the microorganism was most closely related to Actinopolyspora saharensis DSM 45459(T) (99.2 %), Actinopolyspora halophila DSM 43834(T) (99.1 %), and Actinopolyspora algeriensis DSM 45476(T) (99.0 %). Nevertheless, the strain had relatively lower mean values for DNA-DNA relatedness with the above strains (57.2, 68.4, and 45.6 %, respectively). Based on phenotypic features and phylogenetic position, we propose that strain H254(T) represents a novel species of the genus Actinopolyspora, for which the name Actinopolyspora biskrensis sp. nov. is proposed. The type strain of A. biskrensis is strain H254(T) (=DSM 46684(T) =CECT 8576(T)).

  4. How bacterial cell division might cheat turgor pressure - a unified mechanism of septal division in Gram-positive and Gram-negative bacteria.

    Science.gov (United States)

    Erickson, Harold P

    2017-08-01

    An important question for bacterial cell division is how the invaginating septum can overcome the turgor force generated by the high osmolarity of the cytoplasm. I suggest that it may not need to. Several studies in Gram-negative bacteria have shown that the periplasm is isoosmolar with the cytoplasm. Indirect evidence suggests that this is also true for Gram-positive bacteria. In this case the invagination of the septum takes place within the uniformly high osmotic pressure environment, and does not have to fight turgor pressure. A related question is how the V-shaped constriction of Gram-negative bacteria relates to the plate-like septum of Gram-positive bacteria. I collected evidence that Gram-negative bacteria have a latent capability of forming plate-like septa, and present a model in which septal division is the basic mechanism in both Gram-positive and Gram-negative bacteria. © 2017 WILEY Periodicals, Inc.

  5. RNases and Helicases in Gram-Positive Bacteria.

    Science.gov (United States)

    Durand, Sylvain; Condon, Ciaran

    2018-04-01

    RNases are key enzymes involved in RNA maturation and degradation. Although they play a crucial role in all domains of life, bacteria, archaea, and eukaryotes have evolved with their own sets of RNases and proteins modulating their activities. In bacteria, these enzymes allow modulation of gene expression to adapt to rapidly changing environments. Today, >20 RNases have been identified in both Escherichia coli and Bacillus subtilis , the paradigms of the Gram-negative and Gram-positive bacteria, respectively. However, only a handful of these enzymes are common to these two organisms and some of them are essential to only one. Moreover, although sets of RNases can be very similar in closely related bacteria such as the Firmicutes Staphylococcus aureus and B. subtilis , the relative importance of individual enzymes in posttranscriptional regulation in these organisms varies. In this review, we detail the role of the main RNases involved in RNA maturation and degradation in Gram-positive bacteria, with an emphasis on the roles of RNase J1, RNase III, and RNase Y. We also discuss how other proteins such as helicases can modulate the RNA-degradation activities of these enzymes.

  6. Type I and Type II mechanisms of antimicrobial photodynamic therapy: an in vitro study on gram-negative and gram-positive bacteria.

    Science.gov (United States)

    Huang, Liyi; Xuan, Yi; Koide, Yuichiro; Zhiyentayev, Timur; Tanaka, Masamitsu; Hamblin, Michael R

    2012-08-01

    Antimicrobial photodynamic therapy (APDT) employs a non-toxic photosensitizer (PS) and visible light, which in the presence of oxygen produce reactive oxygen species (ROS), such as singlet oxygen ((1) O(2), produced via Type II mechanism) and hydroxyl radical (HO(.), produced via Type I mechanism). This study examined the relative contributions of (1) O(2) and HO(.) to APDT killing of Gram-positive and Gram-negative bacteria. Fluorescence probes, 3'-(p-hydroxyphenyl)-fluorescein (HPF) and singlet oxygen sensor green reagent (SOSG) were used to determine HO(.) and (1) O(2) produced by illumination of two PS: tris-cationic-buckminsterfullerene (BB6) and a conjugate between polyethylenimine and chlorin(e6) (PEI-ce6). Dimethylthiourea is a HO(.) scavenger, while sodium azide (NaN(3)) is a quencher of (1) O(2). Both APDT and killing by Fenton reaction (chemical generation of HO(.)) were carried out on Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa). Conjugate PEI-ce6 mainly produced (1) O(2) (quenched by NaN(3)), while BB6 produced HO(.) in addition to (1) O(2) when NaN(3) potentiated probe activation. NaN(3) also potentiated HPF activation by Fenton reagent. All bacteria were killed by Fenton reagent but Gram-positive bacteria needed a higher concentration than Gram-negatives. NaN(3) potentiated Fenton-mediated killing of all bacteria. The ratio of APDT killing between Gram-positive and Gram-negative bacteria was 2 or 4:1 for BB6 and 25:1 for conjugate PEI-ce6. There was a NaN(3) dose-dependent inhibition of APDT killing using both PEI-ce6 and BB6 against Gram-negative bacteria while NaN(3) almost failed to inhibit killing of Gram-positive bacteria. Azidyl radicals may be formed from NaN(3) and HO(.). It may be that Gram-negative bacteria are more susceptible to HO(.) while Gram-positive bacteria are more susceptible to (1) O(2). The differences in Na

  7. Nucleotide sequence alignment of hdcA from Gram-positive bacteria.

    Science.gov (United States)

    Diaz, Maria; Ladero, Victor; Redruello, Begoña; Sanchez-Llana, Esther; Del Rio, Beatriz; Fernandez, Maria; Martin, Maria Cruz; Alvarez, Miguel A

    2016-03-01

    The decarboxylation of histidine -carried out mainly by some gram-positive bacteria- yields the toxic dietary biogenic amine histamine (Ladero et al. 2010 〈10.2174/157340110791233256〉 [1], Linares et al. 2016 〈http://dx.doi.org/10.1016/j.foodchem.2015.11.013〉〉 [2]). The reaction is catalyzed by a pyruvoyl-dependent histidine decarboxylase (Linares et al. 2011 〈10.1080/10408398.2011.582813〉 [3]), which is encoded by the gene hdcA. In order to locate conserved regions in the hdcA gene of Gram-positive bacteria, this article provides a nucleotide sequence alignment of all the hdcA sequences from Gram-positive bacteria present in databases. For further utility and discussion, see 〈http://dx.doi.org/ 10.1016/j.foodcont.2015.11.035〉〉 [4].

  8. Cystic neutrophilic granulomatous mastitis: an underappreciated pattern strongly associated with gram-positive bacilli.

    Science.gov (United States)

    Renshaw, Andrew A; Derhagopian, Robert P; Gould, Edwin W

    2011-09-01

    Although granulomatous lobular mastitis is associated with gram-positive bacilli such as Corynebacterium, this association is not well known. We report 3 cases of mastitis caused by gram-positive bacilli. All 3 abscesses were suppurative with distinct enlarged cystic spaces in which rare gram-positive bacilli were identified. Two cases were also granulomatous. Cultures in all 3 cases were negative. All 3 patients recovered after biopsy and tetracycline-based therapy. Infection in the breast by gram-positive bacilli is associated with a distinct histologic pattern, including cystic spaces in the setting of neutrophilic/granulomatous inflammation that can be recognized and should prompt careful search for the organism within enlarged vacuoles.

  9. Pleural effusion adenosine deaminase: a candidate biomarker to discriminate between Gram-negative and Gram-positive bacterial infections of the pleural space

    Directory of Open Access Journals (Sweden)

    Ruolin Li

    2016-05-01

    Full Text Available OBJECTIVES: Delay in the treatment of pleural infection may contribute to its high mortality. In this retrospective study, we aimed to evaluate the diagnostic accuracy of pleural adenosine deaminase in discrimination between Gram-negative and Gram-positive bacterial infections of the pleural space prior to selecting antibiotics. METHODS: A total of 76 patients were enrolled and grouped into subgroups according to Gram staining: 1 patients with Gram-negative bacterial infections, aged 53.2±18.6 years old, of whom 44.7% had empyemas and 2 patients with Gram-positive bacterial infections, aged 53.5±21.5 years old, of whom 63.1% had empyemas. The pleural effusion was sampled by thoracocentesis and then sent for adenosine deaminase testing, biochemical testing and microbiological culture. The Mann-Whitney U test was used to examine the differences in adenosine deaminase levels between the groups. Correlations between adenosine deaminase and specified variables were also quantified using Spearman’s correlation coefficient. Moreover, receiver operator characteristic analysis was performed to evaluate the diagnostic accuracy of pleural effusion adenosine deaminase. RESULTS: Mean pleural adenosine deaminase levels differed significantly between Gram-negative and Gram-positive bacterial infections of the pleural space (191.8±32.1 U/L vs 81.0±16.9 U/L, p<0.01. The area under the receiver operator characteristic curve was 0.689 (95% confidence interval: 0.570, 0.792, p<0.01 at the cutoff value of 86 U/L. Additionally, pleural adenosine deaminase had a sensitivity of 63.2% (46.0-78.2%; a specificity of 73.7% (56.9-86.6%; positive and negative likelihood ratios of 2.18 and 0.50, respectively; and positive and negative predictive values of 70.6% and 66.7%, respectively. CONCLUSIONS: Pleural effusion adenosine deaminase is a helpful alternative biomarker for early and quick discrimination of Gram-negative from Gram-positive bacterial infections of the

  10. Cellular reprogramming by gram-positive bacterial components: a review.

    LENUS (Irish Health Repository)

    Buckley, Julliette M

    2012-02-03

    LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance.

  11. Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study

    Directory of Open Access Journals (Sweden)

    Azam A

    2012-12-01

    Full Text Available Ameer Azam,1,2 Arham S Ahmed,2 Mohammad Oves,3 Mohammad S Khan,3 Sami S Habib,1 Adnan Memic11Centre of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia; 2Centre of Excellence in Materials Science (Nanomaterials, 3Department of Agricultural Microbiology, Aligarh Muslim University, Aligarh, IndiaBackground: Nanomaterials have unique properties compared to their bulk counterparts. For this reason, nanotechnology has attracted a great deal of attention from the scientific community. Metal oxide nanomaterials like ZnO and CuO have been used industrially for several purposes, including cosmetics, paints, plastics, and textiles. A common feature that these nanoparticles exhibit is their antimicrobial behavior against pathogenic bacteria. In this report, we demonstrate the antimicrobial activity of ZnO, CuO, and Fe2O3 nanoparticles against Gram-positive and Gram-negative bacteria.Methods and results: Nanosized particles of three metal oxides (ZnO, CuO, and Fe2O3 were synthesized by a sol–gel combustion route and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy techniques. X-ray diffraction results confirmed the single-phase formation of all three nanomaterials. The particle sizes were observed to be 18, 22, and 28 nm for ZnO, CuO, and Fe2O3, respectively. We used these nanomaterials to evaluate their antibacterial activity against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa and Gram-positive (Staphylococcus aureus and Bacillus subtilis bacteria.Conclusion: Among the three metal oxide nanomaterials, ZnO showed greatest antimicrobial activity against both Gram-positive and Gram-negative bacteria used in this study. It was observed that ZnO nanoparticles have excellent bactericidal potential, while Fe2O3 nanoparticles exhibited the least bactericidal activity. The order of antibacterial activity was demonstrated to be the following: ZnO > CuO > Fe2O3

  12. Mechanistic antimicrobial approach of extracellularly synthesized silver nanoparticles against gram positive and gram negative bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tamboli, Dhawal P.; Lee, Dae Sung, E-mail: daesung@knu.ac.kr

    2013-09-15

    Highlights: • Bacterial extracelluar enzymes stabilized the silver nanoparticles (AgNPs). • AgNPs formation was characterized by analytical techniques such as UV–vis, TEM, and FTIR. • AgNPs showed obvious antimicrobial activity against both gram positive and gram negative microorganisms. • A mechanism of AgNPs’ antimicrobial activity was proposed. -- Abstract: The development of eco-friendly and reliable processes for the synthesis of nanoparticles has attracted considerable interest in nanotechnology. In this study, an extracellular enzyme system of a newly isolated microorganism, Exiguobacterium sp. KNU1, was used for the reduction of AgNO{sub 3} solutions to silver nanoparticles (AgNPs). The extracellularly biosynthesized AgNPs were characterized by UV–vis spectroscopy, Fourier transform infra-red spectroscopy and transmission electron microscopy. The AgNPs were approximately 30 nm (range 5–50 nm) in size, well-dispersed and spherical. The AgNPs were evaluated for their antimicrobial effects on different gram negative and gram positive bacteria using the minimum inhibitory concentration method. Reasonable antimicrobial activity against Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus was observed. The morphological changes occurred in all the microorganisms tested. In particular, E. coli exhibited DNA fragmentation after being treated with the AgNPs. Finally, the mechanism for their bactericidal activity was proposed according to the results of scanning electron microscopy and single cell gel electrophoresis.

  13. Mechanistic antimicrobial approach of extracellularly synthesized silver nanoparticles against gram positive and gram negative bacteria

    International Nuclear Information System (INIS)

    Tamboli, Dhawal P.; Lee, Dae Sung

    2013-01-01

    Highlights: • Bacterial extracelluar enzymes stabilized the silver nanoparticles (AgNPs). • AgNPs formation was characterized by analytical techniques such as UV–vis, TEM, and FTIR. • AgNPs showed obvious antimicrobial activity against both gram positive and gram negative microorganisms. • A mechanism of AgNPs’ antimicrobial activity was proposed. -- Abstract: The development of eco-friendly and reliable processes for the synthesis of nanoparticles has attracted considerable interest in nanotechnology. In this study, an extracellular enzyme system of a newly isolated microorganism, Exiguobacterium sp. KNU1, was used for the reduction of AgNO 3 solutions to silver nanoparticles (AgNPs). The extracellularly biosynthesized AgNPs were characterized by UV–vis spectroscopy, Fourier transform infra-red spectroscopy and transmission electron microscopy. The AgNPs were approximately 30 nm (range 5–50 nm) in size, well-dispersed and spherical. The AgNPs were evaluated for their antimicrobial effects on different gram negative and gram positive bacteria using the minimum inhibitory concentration method. Reasonable antimicrobial activity against Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus was observed. The morphological changes occurred in all the microorganisms tested. In particular, E. coli exhibited DNA fragmentation after being treated with the AgNPs. Finally, the mechanism for their bactericidal activity was proposed according to the results of scanning electron microscopy and single cell gel electrophoresis

  14. Daptomycin treatment in Gram-positive vascular graft infections

    Directory of Open Access Journals (Sweden)

    Francisco Arnaiz de las Revillas

    2018-03-01

    Full Text Available Background: Daptomycin is a bactericidal antibiotic approved for the treatment of skin and soft tissue infections and right-side endocarditis. However, there is a lack of published data outlining its usefulness in vascular graft infections (VGI. The aim of this study was to describe the clinical experience of daptomycin use in the treatment of VGI caused by Gram-positive bacteria. Methods: This was a retrospective cohort study of patients diagnosed with VGI receiving daptomycin at a tertiary care hospital during the period January 2010 to December 2012. Results: Of a total 1066 consecutive patients who had undergone vascular grafts (VG, 25 were diagnosed with VGI. Fifteen of these patients (11 prosthetic VG, three autologous VG, one both types received daptomycin (median dose 6.7 mg/kg/day, range 4.1–7.1 mg/kg/day; median age 69 years, range 45–83 years; 80% male. The infected bypass was removed in 13 cases. The most common reason for selecting daptomycin was kidney failure (53%. The Gram-positive organisms isolated were coagulase-negative Staphylococcus (n = 10, Staphylococcus aureus (n = 3 (two methicillin-resistant S. aureus, Enterococcus faecium (n = 2, and Enterococcus faecalis (n = 1. The mean follow-up was 69 months (interquartile range 48–72 months. Ten patients (66.7% achieved complete healing of the VGI. A recurrence of the infection was observed in 100% of patients in whom the bypass was not removed. Among patients who did not achieve complete healing, one needed a supracondylar amputation and one died as a consequence of infection. Five patients received treatment with rifampicin in addition to daptomycin and they were all cured. Conclusions: The use of daptomycin and surgery for Gram-positive VGI was effective and well tolerated, and this may be a good alternative for the treatment of VGI in patients with peripheral arterial disease in whom renal insufficiency is common. Keywords: Daptomycin, Gram-positive, Vascular

  15. Clinical update on linezolid in the treatment of Gram-positive bacterial infections

    Science.gov (United States)

    Ager, Sally; Gould, Kate

    2012-01-01

    Gram-positive pathogens are a significant cause of morbidity and mortality in both community and health care settings. Glycopeptides have traditionally been the antibiotics of choice for multiresistant Gram-positive pathogens but there are problems with their use, including the emergence of glycopeptide-resistant strains, tissue penetration, and achieving and monitoring adequate serum levels. Newer antibiotics such as linezolid, a synthetic oxazolidinone, are available for the treatment of resistant Gram-positive bacteria. Linezolid is active against a wide range of Gram-positive bacteria and has been generally available for the treatment of Gram-positive infections since 2000. There are potential problems with linezolid use, including its bacteriostatic action and the relatively high incidence of reported adverse effects, particularly with long-term use. Long-term use may also be complicated by the development of resistance. However, linezolid has been shown to be clinically useful in the treatment of several serious infections where traditionally bacteriocidal agents have been required and many of its adverse effects are reversible on cessation. It has also been shown to be a cost-effective treatment option in several studies, with its high oral bioavailability allowing an early change from intravenous to oral formulations with consequent earlier patient discharge and lower inpatient costs. PMID:22787406

  16. Oceanospirillum nioense sp. nov., a marine bacterium isolated from sediment sample of Palk bay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.K.; Bhumika, V.; Thomas, M.; AnilKumar, P.; Srinivas, T.N.R.

    A novel Gram-negative, spiral shaped, motile bacterium, designated strain NIO-S6T, was isolated from a sediment sample collected from Offshore Rameswaram, Tamilnadu, India. Strain NIO-S6 sup(T) was found to be positive for oxidase, DNase and lysine...

  17. DMPD: Cellular reprogramming by gram-positive bacterial components: a review. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16885502 Cellular reprogramming by gram-positive bacterial components: a review. Bu...(.csml) Show Cellular reprogramming by gram-positive bacterial components: a review. PubmedID 16885502 Title... Cellular reprogramming by gram-positive bacterial components: a review. Authors

  18. Using a portable Raman spectrometer to detect carotenoids of halophilic prokaryotes in synthetic inclusions in NaCl, KCl, and sulfates.

    Science.gov (United States)

    Jehlička, Jan; Culka, Adam; Mana, Lilly; Oren, Aharon

    2018-05-03

    Cell suspensions of the haloarchaea Halorubrum sodomense and Halobacterium salinarum and the extremely halophilic bacterium Salinibacter ruber (Bacteroidetes) in saturated solutions of chlorides and sulfates (NaCl, KCl, MgSO 4 ·7H 2 O, K 2 SO 4 , and (NH 4 )Al(SO 4 ) 2 ·12H 2 O) were left to evaporate to produce micrometric inclusions in laboratory-grown crystals. Raman spectra of these pinkish inclusions were obtained using a handheld Raman spectrometer with green excitation (532 nm). This portable instrument does not include any microscopic tool. Acceptable Raman spectra of carotenoids were obtained in the range of 200-4000 cm -1 . This detection achievement was related to the mode of illumination and collection of scattered light as well as due to resonance Raman enhancement of carotenoid signals under green excitation. The position of diagnostic Raman carotenoid bands corresponds well to those specific carotenoids produced by a given halophile. To our best knowledge, this is the first study of carotenoids included in the laboratory in crystalline chlorides and sulfates, using a miniature portable Raman spectrometer. Graphical abstract ᅟ.

  19. Flavobacterium nitratireducens sp. nov., an amylolytic bacterium of the family Flavobacteriaceae isolated from coastal surface seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Nupur; Bhumika, V.; Srinivas, T.N.R.; AnilKumar, P.

    A novel Gram-negative, rod-shaped, non-motile bacterium, designated strain N1 sup(T), was isolated from a marine water sample collected from the sea shore, Bay of Bengal, Visakhapatnam, India. The strain was positive for starch hydrolysis, nitrate...

  20. Raman Spectroscopy of Xylitol Uptake and Metabolism in Gram-Positive and Gram-Negative Bacteria▿

    Science.gov (United States)

    Palchaudhuri, Sunil; Rehse, Steven J.; Hamasha, Khozima; Syed, Talha; Kurtovic, Eldar; Kurtovic, Emir; Stenger, James

    2011-01-01

    Visible-wavelength Raman spectroscopy was used to investigate the uptake and metabolism of the five-carbon sugar alcohol xylitol by Gram-positive viridans group streptococcus and the two extensively used strains of Gram-negative Escherichia coli, E. coli C and E. coli K-12. E. coli C, but not E. coli K-12, contains a complete xylitol operon, and the viridans group streptococcus contains an incomplete xylitol operon used to metabolize the xylitol. Raman spectra from xylitol-exposed viridans group streptococcus exhibited significant changes that persisted even in progeny grown from the xylitol-exposed mother cells in a xylitol-free medium for 24 h. This behavior was not observed in the E. coli K-12. In both viridans group streptococcus and the E. coli C derivative HF4714, the metabolic intermediates are stably formed to create an anomaly in bacterial normal survival. The uptake of xylitol by Gram-positive and Gram-negative pathogens occurs even in the presence of other high-calorie sugars, and its stable integration within the bacterial cell wall may discontinue bacterial multiplication. This could be a contributing factor for the known efficacy of xylitol when taken as a prophylactic measure to prevent or reduce occurrences of persistent infection. Specifically, these bacteria are causative agents for several important diseases of children such as pneumonia, otitis media, meningitis, and dental caries. If properly explored, such an inexpensive and harmless sugar-alcohol, alone or used in conjunction with fluoride, would pave the way to an alternative preventive therapy for these childhood diseases when the causative pathogens have become resistant to modern medicines such as antibiotics and vaccine immunotherapy. PMID:21037297

  1. Halophiles, coming stars for industrial biotechnology.

    Science.gov (United States)

    Yin, Jin; Chen, Jin-Chun; Wu, Qiong; Chen, Guo-Qiang

    2015-11-15

    Industrial biotechnology aims to produce chemicals, materials and biofuels to ease the challenges of shortage on petroleum. However, due to the disadvantages of bioprocesses including energy consuming sterilization, high fresh water consumption, discontinuous fermentation to avoid microbial contamination, highly expensive stainless steel fermentation facilities and competing substrates for human consumption, industrial biotechnology is less competitive compared with chemical processes. Recently, halophiles have shown promises to overcome these shortcomings. Due to their unique halophilic properties, some halophiles are able to grow in high pH and high NaCl containing medium under higher temperature, allowing fermentation processes to run contamination free under unsterile conditions and continuous way. At the same time, genetic manipulation methods have been developed for halophiles. So far, halophiles have been used to produce bioplastics polyhydroxyalkanoates (PHA), ectoines, enzymes, and bio-surfactants. Increasing effects have been made to develop halophiles into a low cost platform for bioprocessing with advantages of low energy, less fresh water consumption, low fixed capital investment, and continuous production. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Ponticoccus marisrubri sp. nov., a moderately halophilic marine bacterium of the family Rhodobacteraceae

    KAUST Repository

    Zhang, Guishan

    2017-10-06

    Strain SJ5A-1T, a Gram-stain-negative, coccus-shaped, non-motile, aerobic bacterium, was isolated from the brine-seawater interface of the Erba Deep in the Red Sea, Saudi Arabia. The colonies of strain SJ5A-1T have a beige to pale-brown pigmentation, are approximately 0.5-0.7 µm in diameter, and are catalase and oxidase positive. Growth occurred optimally at 30-33 °C, pH 7.0-7.5, and in the presence of 9.0-12.0 % NaCl (w/v). Phylogenetic analysis of the 16S rRNA gene indicates that strain SJ5A-1T is a member of the genus Ponticoccus within the family Rhodobacteraceae. Ponticoccus litoralis DSM 18986T is the most closely related described species based on 16S rRNA gene sequence identity (96.7 %). The DNA-DNA hybridization value between strain SJ5A-1T and P. litoralis DSM 18986T was 36.7 %. The major respiratory quinone of strain SJ5A-1T is Q-10; it predominantly uses the fatty acids C18 : 1 (54.2 %), C18 : 0 (11.2 %), C16 : 0 (8.6 %), 11-methyl C18 : 1ω7c (7.7 %), C19 : 0cyclo ω8c (3.3 %), and C12 : 1 3-OH (3.5 %), and its major polar lipids are phosphatidylethanolamine, phosphatidylglycerol, phosphocholine, an unknown aminolipid, an unknown phospholipid and two unknown lipids. The genome draft of strain SJ5A-1T as presented here is 4 562 830 bp in size and the DNA G+C content is 68.0 mol %. Based on phenotypic, phylogenetic and genotypic data, strain SJ5A-1T represents a novel species in the genus Ponticoccus, for which we propose the name Ponticoccus marisrubri sp. nov. The type strain of P. marisrubri is SJ5A-1T (=JCM 19520T=ACCC19863T).

  3. Detection and Antibiotic Susceptibility Pattern of Biofilm Producing Gram Positive and Gram Negative Bacteria Isolated From a Tertiary Care Hospital of Pakistan

    Directory of Open Access Journals (Sweden)

    Iqbal, M.

    2011-01-01

    Full Text Available Microorganisms adhere to non-living material or living tissue, and form biofilms made up of extracellular polymers/slime. Biofilm-associated microorganisms behave differently from free-floating bacteria with respect to growth rates and ability to resist antimicrobial treatments and therefore pose a public health problem. The objective of this study is to detect the prevalence of biofilm producers among Gram positive and Gram negative bacteria isolated from clinical specimens, and to study their antimicrobial susceptibility pattern. The study was carried out from October 2009 to March 2010, at the Department of Microbiology, Army Medical College/ National University of Sciences and Technology (NUST, Rawalpindi, Pakistan. Clinical specimens were received from various wards of a tertiary care hospital. These were dealt by standard microbiological procedures. Gram positive and Gram negative bacteria isolated were subjected to biofilm detection by congo red agar method (CRA. Antimicrobial susceptibility testing of those isolates, which showed positive results (slime production, was done according to the Kirby-Bauer disc diffusion technique. A total of 150 isolates were tested for the production of biofilm/slime. Among them, 81 isolates showed positive results. From these 81, 51 were Gram positive and 30 were Gram negative. All the 81(54% slime producers showed reduced susceptibility to majority of antibiotics. Bacterial biofilms are an important virulence factor associated with chronic nosocomial infection. Detection of biofilm forming organisms can help in appropriate antibiotic choice.

  4. From Genome to Function: Systematic Analysis of the Soil Bacterium Bacillus Subtilis

    Science.gov (United States)

    Crawshaw, Samuel G.; Wipat, Anil

    2001-01-01

    Bacillus subtilis is a sporulating Gram-positive bacterium that lives primarily in the soil and associated water sources. Whilst this bacterium has been studied extensively in the laboratory, relatively few studies have been undertaken to study its activity in natural environments. The publication of the B. subtilis genome sequence and subsequent systematic functional analysis programme have provided an opportunity to develop tools for analysing the role and expression of Bacillus genes in situ. In this paper we discuss analytical approaches that are being developed to relate genes to function in environments such as the rhizosphere. PMID:18628943

  5. A classification system for plasmids from Enterococci and other Gram-positive bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Garcia-Migura, Lourdes; Valenzuela, Antonio Jesus Sanchez

    2010-01-01

    A classification system for plasmids isolated from enterococci and other Gram-positive bacteria was developed based on 111 published plasmid sequences from enterococci and other Gram-positive bacteria; mostly staphylococci. Based on PCR amplification of conserved areas of the replication initiating....... Furthermore, conjugation experiments were performed obtaining 30 transconjugants when selecting for antimicrobial resistance. Among them 19 gave no positive amplicons indicating presence of rep-families not tested for in this experimental setup....

  6. In vitro activity of XF-73, a novel antibacterial agent, against antibiotic-sensitive and -resistant Gram-positive and Gram-negative bacterial species.

    Science.gov (United States)

    Farrell, David J; Robbins, Marion; Rhys-Williams, William; Love, William G

    2010-06-01

    The antibacterial activity of XF-73, a dicationic porphyrin drug, was investigated against a range of Gram-positive and Gram-negative bacteria with known antibiotic resistance profiles, including resistance to cell wall synthesis, protein synthesis, and DNA and RNA synthesis inhibitors as well as cell membrane-active antibiotics. Antibiotic-sensitive strains for each of the bacterial species tested were also included for comparison purposes. XF-73 was active [minimum inhibitory concentration (MIC) 0.25-4 mg/L] against all of the Gram-positive bacteria tested, irrespective of the antibiotic resistance profile of the isolates, suggesting that the mechanism of action of XF-73 is unique compared with the major antibiotic classes. Gram-negative activity was lower (MIC 1 mg/L to > 64 mg/L). Minimum bactericidal concentration data confirmed that the activity of XF-73 was bactericidal. Time-kill kinetics against healthcare-associated and community-associated meticillin-resistant Staphylococcus aureus isolates demonstrated that XF-73 was rapidly bactericidal, with > 5 log(10) kill obtained after 15 min at 2 x MIC, the earliest time point sampled. The post-antibiotic effect (PAE) for XF-73 under conditions where the PAE for vancomycin was 5.4 h. XF-73 represents a novel broad-spectrum Gram-positive antibacterial drug with potentially beneficial characteristics for the treatment and prevention of Gram-positive bacterial infections. 2010. Published by Elsevier B.V.

  7. Stable transformation of the gram-positive phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus with several cloning vectors.

    OpenAIRE

    Laine, M J; Nakhei, H; Dreier, J; Lehtilä, K; Meletzus, D; Eichenlaub, R; Metzler, M C

    1996-01-01

    In this paper we describe transformation of Clavibacter michiganensis subsp. sepedonicus, the potato ring rot bacterium, with plasmid vectors. Three of the plasmids used, pDM100, pDM302, and pDM306, contain the origin of replication from pCM1, a native plasmid of C. michiganensis subsp. michiganensis. We constructed two new cloning vectors, pHN205 and pHN216, by using the origin of replication of pCM2, another native plasmid of C. michiganensis subsp. michiganensis. Plasmids pDM302, pHN205, a...

  8. Phenotypic characterization and 16S rDNA identification of culturable non-obligate halophilic bacterial communities from a hypersaline lake, La Sal del Rey, in extreme South Texas (USA).

    Science.gov (United States)

    Phillips, Kristen; Zaidan, Frederic; Elizondo, Omar R; Lowe, Kristine L

    2012-02-02

    La Sal del Rey ("the King's Salt") is one of several naturally-occurring salt lakes in Hidalgo County, Texas and is part of the Lower Rio Grande Valley National Wildlife Refuge. The research objective was to isolate and characterize halophilic microorganisms from La Sal del Rey. Water samples were collected from the lake and a small creek that feeds into the lake. Soil samples were collected from land adjacent to the water sample locations. Sample salinity was determined using a refractometer. Samples were diluted and cultured on a synthetic saline medium to grow halophilic bacteria. The density of halophiles was estimated by viable plate counts. A collection of isolates was selected, gram-stained, tested for catalase, and characterized using API 20E® test strips. Isolates were putatively identified by sequencing the 16S rDNA. Carbon source utilization by the microbial community from each sample site was examined using EcoPlate™ assays and the carbon utilization total activity of the community was determined. Results showed that salinity ranged from 4 parts per thousand (ppt) at the lake water source to 420 ppt in water samples taken just along the lake shore. The density of halophilic bacteria in water samples ranged from 1.2 × 102 - 5.2 × 103 colony forming units per ml (cfu ml-1) whereas the density in soil samples ranged from 4.0 × 105 - 2.5 × 106 colony forming units per gram (cfu g-1). In general, as salinity increased the density of the bacterial community decreased. Microbial communities from water and soil samples were able to utilize 12 - 31 carbon substrates. The greatest number of substrates utilized was by water-borne communities compared to soil-based communities, especially at lower salinities. The majority of bacteria isolated were gram-negative, catalase-positive, rods. Biochemical profiles constructed from API 20E® test strips showed that bacterial isolates from low-salinity water samples (4 ppt) showed the greatest phenotypic diversity

  9. [Diversity and enzyme-producing activity of culturable halophilic bacteria in Daishan Saltern of East China].

    Science.gov (United States)

    Yang, Dan-Dan; Li, Qian; Huang, Jing-Jing; Chen, Min

    2012-11-01

    Soil and saline water samples were collected from the Daishan Saltern of East China, and the halophilic bacteria were isolated and cultured by using selective media, aimed to investigate the diversity and enzyme-producing activity of culturable halophilic bacteria in saltern environment. A total of 181 strains were isolated by culture-dependent method. Specific primers were used to amplify the 16S rRNA gene of bacteria and archaea. The operation taxonomy units (OTUs) were determined by ARDRA method, and the representative strain of each OTU was sequenced. The phylogenetic position of all the isolated strains was determined by 16S rRNA sequencing. The results showed that the isolated 181 strains displayed 21 operational taxonomic units (OTUs), of which, 12 OTUs belonged to halophilic bacteria, and the others belonged to halophilic archaea. Phylogenetic analysis indicated that there were 7 genera presented among the halophilic bacteria group, and 4 genera presented among the halophilic archaea group. The dominant halophilic strains were of Halomonas and Haloarcula, with 46.8% in halophilic bacteria and 49.1% in halophilic archaea group, respectively. Enzyme-producing analysis indicated that most strains displayed enzyme-producing activity, including the activities of producing amylase, proteinase and lipase, and the dominant strains capable of enzyme-producing were of Haloarcula. Our results showed that in the environment of Daishan Saltern, there existed a higher diversity of halophilic bacteria, being a source sink for screening enzyme-producing bacterial strains.

  10. Neither Single nor a Combination of Routine Laboratory Parameters can Discriminate between Gram-positive and Gram-negative Bacteremia

    Science.gov (United States)

    Ratzinger, Franz; Dedeyan, Michel; Rammerstorfer, Matthias; Perkmann, Thomas; Burgmann, Heinz; Makristathis, Athanasios; Dorffner, Georg; Loetsch, Felix; Blacky, Alexander; Ramharter, Michael

    2015-01-01

    Adequate early empiric antibiotic therapy is pivotal for the outcome of patients with bloodstream infections. In clinical practice the use of surrogate laboratory parameters is frequently proposed to predict underlying bacterial pathogens; however there is no clear evidence for this assumption. In this study, we investigated the discriminatory capacity of predictive models consisting of routinely available laboratory parameters to predict the presence of Gram-positive or Gram-negative bacteremia. Major machine learning algorithms were screened for their capacity to maximize the area under the receiver operating characteristic curve (ROC-AUC) for discriminating between Gram-positive and Gram-negative cases. Data from 23,765 patients with clinically suspected bacteremia were screened and 1,180 bacteremic patients were included in the study. A relative predominance of Gram-negative bacteremia (54.0%), which was more pronounced in females (59.1%), was observed. The final model achieved 0.675 ROC-AUC resulting in 44.57% sensitivity and 79.75% specificity. Various parameters presented a significant difference between both genders. In gender-specific models, the discriminatory potency was slightly improved. The results of this study do not support the use of surrogate laboratory parameters for predicting classes of causative pathogens. In this patient cohort, gender-specific differences in various laboratory parameters were observed, indicating differences in the host response between genders. PMID:26522966

  11. Draft Genome Sequence of the Efficient Bioflocculant-Producing Bacterium Paenibacillus sp. Strain A9

    Science.gov (United States)

    Liu, Jin-liang; Hu, Xiao-min

    2013-01-01

    Paenibacillus sp. strain A9 is an important bioflocculant-producing bacterium, isolated from a soil sample, and is pale pink-pigmented, aerobic, and Gram-positive. Here, we report the draft genome sequence and the initial findings from a preliminary analysis of strain A9, which is a novel species of Paenibacillus. PMID:23618713

  12. Diversity of pigmented Gram-positive bacteria associated with marine macroalgae from Antarctica.

    Science.gov (United States)

    Leiva, Sergio; Alvarado, Pamela; Huang, Ying; Wang, Jian; Garrido, Ignacio

    2015-12-01

    Little is known about the diversity and roles of Gram-positive and pigmented bacteria in Antarctic environments, especially those associated with marine macroorganisms. This work is the first study about the diversity and antimicrobial activity of culturable pigmented Gram-positive bacteria associated with marine Antarctic macroalgae. A total of 31 pigmented Gram-positive strains were isolated from the surface of six species of macroalgae collected in the King George Island, South Shetland Islands. On the basis of 16S rRNA gene sequence similarities ≥99%, 18 phylotypes were defined, which were clustered into 11 genera of Actinobacteria (Agrococcus, Arthrobacter, Brachybacterium, Citricoccus, Kocuria, Labedella, Microbacterium, Micrococcus, Rhodococcus, Salinibacterium and Sanguibacter) and one genus of the Firmicutes (Staphylococcus). It was found that five isolates displayed antimicrobial activity against a set of macroalgae-associated bacteria. The active isolates were phylogenetically related to Agrococcus baldri, Brachybacterium rhamnosum, Citricoccus zhacaiensis and Kocuria palustris. The results indicate that a diverse community of pigmented Gram-positive bacteria is associated with Antartic macroalgae and suggest its potential as a promising source of antimicrobial and pigmented natural compounds. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Organo-Selenium Coatings Inhibit Gram-Negative and Gram-Positive Bacterial Attachment to Ophthalmic Scleral Buckle Material.

    Science.gov (United States)

    Tran, Phat; Arnett, Avery; Jarvis, Courtney; Mosley, Thomas; Tran, Khien; Hanes, Rob; Webster, Dan; Mitchell, Kelly; Dominguez, Leo; Hamood, Abdul; Reid, Ted W

    2017-09-01

    Biofilm formation is a problem for solid and sponge-type scleral buckles. This can lead to complications that require removal of the buckle, and result in vision loss due to related ocular morbidity, primarily infection, or recurrent retinal detachment. We investigate the ability of a covalent organo-selenium coating to inhibit biofilm formation on a scleral buckle. Sponge and solid Labtican brand scleral buckles were coated with organo-selenium coupled to a silyation reagent. Staphylococcus aureus biofilm formation was monitored by a standard colony-forming unit assay and the confocal laser scanning microscopy, while Pseudomonas aeruginosa biofilm formation was examined by scanning electron microscopy. Stability studies were done, by soaking in phosphate buffer saline (PBS) at room temperature for 2 months. Toxicity against human corneal epithelial cell was examined by growing the cells in the presence of organo-selenium-coated scleral buckles. The organo-selenium coating inhibited biofilm formation by gram-negative and gram-positive bacteria. The buckle coatings also were shown to be fully active after soaking in PBS for 2 months. The organo-selenium coatings had no effect on the viability of human corneal epithelial cells. Organo-selenium can be used to covalently coat a scleral buckle, which is stable and inhibits biofilm formation for gram-negative and gram-positive bacteria. The organo-selenium buckle coating was stable and nontoxic to cell culture. This technology provides a means to inhibit bacterial attachment to devices attached to the eye, without damage to ocular cells.

  14. Halophilic microbial communities in deteriorated buildings.

    Science.gov (United States)

    Adamiak, Justyna; Otlewska, Anna; Gutarowska, Beata

    2015-10-01

    Halophilic microorganisms were traditionally isolated from an aquatic environment. There has been little research conducted into halophiles inhabiting the terrestrial environment in which historic monuments deteriorate. Salt efflorescence deposited on the walls is an observed phenomenon on the surface of historic buildings, and would favour the growth of halophiles. However, some conditions have to be fulfilled in order for efflorescence to occur: (1) the presence of salts, (2) porosity, (3) a source of water. Salt crystallization influences the material structure (cracking, detachment, material loss), but active growth of halophilic microorganisms may be a serious threat to historic materials as well, leading to aesthetical changes such as coloured biofilms, orange to pink or even violet stains. This is why it is important to investigate halophilic microorganisms, taking into consideration both the environmental conditions they need to grow in, material characteristics they inhabit, the mechanisms they possess to cope with osmotic stress, and the methods that should be applied for their identification.

  15. Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract.

    Science.gov (United States)

    Kline, Kimberly A; Lewis, Amanda L

    2016-04-01

    Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.

  16. Gram-negative and -positive bacteria differentiation in blood culture samples by headspace volatile compound analysis.

    Science.gov (United States)

    Dolch, Michael E; Janitza, Silke; Boulesteix, Anne-Laure; Graßmann-Lichtenauer, Carola; Praun, Siegfried; Denzer, Wolfgang; Schelling, Gustav; Schubert, Sören

    2016-12-01

    Identification of microorganisms in positive blood cultures still relies on standard techniques such as Gram staining followed by culturing with definite microorganism identification. Alternatively, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or the analysis of headspace volatile compound (VC) composition produced by cultures can help to differentiate between microorganisms under experimental conditions. This study assessed the efficacy of volatile compound based microorganism differentiation into Gram-negatives and -positives in unselected positive blood culture samples from patients. Headspace gas samples of positive blood culture samples were transferred to sterilized, sealed, and evacuated 20 ml glass vials and stored at -30 °C until batch analysis. Headspace gas VC content analysis was carried out via an auto sampler connected to an ion-molecule reaction mass spectrometer (IMR-MS). Measurements covered a mass range from 16 to 135 u including CO2, H2, N2, and O2. Prediction rules for microorganism identification based on VC composition were derived using a training data set and evaluated using a validation data set within a random split validation procedure. One-hundred-fifty-two aerobic samples growing 27 Gram-negatives, 106 Gram-positives, and 19 fungi and 130 anaerobic samples growing 37 Gram-negatives, 91 Gram-positives, and two fungi were analysed. In anaerobic samples, ten discriminators were identified by the random forest method allowing for bacteria differentiation into Gram-negative and -positive (error rate: 16.7 % in validation data set). For aerobic samples the error rate was not better than random. In anaerobic blood culture samples of patients IMR-MS based headspace VC composition analysis facilitates bacteria differentiation into Gram-negative and -positive.

  17. Physico-Chemical-Managed Killing of Penicillin-Resistant Static and Growing Gram-Positive and Gram-Negative Vegetative Bacteria

    Science.gov (United States)

    Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor); Farris, III, Alex F. (Inventor)

    2012-01-01

    Systems and methods for the use of compounds from the Hofmeister series coupled with specific pH and temperature to provide rapid physico-chemical-managed killing of penicillin-resistant static and growing Gram-positive and Gram-negative vegetative bacteria. The systems and methods represent the more general physico-chemical enhancement of susceptibility for a wide range of pathological macromolecular targets to clinical management by establishing the reactivity of those targets to topically applied drugs or anti-toxins.

  18. Support vector machine with a Pearson VII function kernel for discriminating halophilic and non-halophilic proteins.

    Science.gov (United States)

    Zhang, Guangya; Ge, Huihua

    2013-10-01

    Understanding of proteins adaptive to hypersaline environment and identifying them is a challenging task and would help to design stable proteins. Here, we have systematically analyzed the normalized amino acid compositions of 2121 halophilic and 2400 non-halophilic proteins. The results showed that halophilic protein contained more Asp at the expense of Lys, Ile, Cys and Met, fewer small and hydrophobic residues, and showed a large excess of acidic over basic amino acids. Then, we introduce a support vector machine method to discriminate the halophilic and non-halophilic proteins, by using a novel Pearson VII universal function based kernel. In the three validation check methods, it achieved an overall accuracy of 97.7%, 91.7% and 86.9% and outperformed other machine learning algorithms. We also address the influence of protein size on prediction accuracy and found the worse performance for small size proteins might be some significant residues (Cys and Lys) were missing in the proteins. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Positive role of peptidoglycan breaks in lactococcal biofilm formation

    NARCIS (Netherlands)

    Mercier, C; Durrieu, C; Briandet, R; Domakova, E; Tremblay, J; Buist, G; Kulakauskas, S

    2002-01-01

    Bacterial attachment to solid matrices depends on adhesive molecules present on the cell surface. Here we establish a positive correlation between peptidoglycan (PG) breaks, rather than particular molecules, and biofilm-forming capacity in the Gram-positive bacterium Lactococcus lactis. The L.

  20. Draft Genome Sequence of Nafulsella turpanensis ZLM-10T, a Novel Member of the Family Flammeovirgaceae.

    Science.gov (United States)

    Zhang, Lei; Si, Meiru; Zhu, Lingfang; Li, Changfu; Wei, Yahong; Shen, Xihui

    2014-04-03

    Nafulsella turpanensis ZLM-10(T) is a slightly halophilic, Gram-negative, rod-shaped, gliding, pale-pink-pigmented bacterium in the family Flammeovirgaceae, and it shows resistance to gentamicin, kanamycin, neomycin, and streptomycin. Here, we report the genome sequence of N. turpanensis strain ZLM-10(T), which has a 4.8-Mb genome and a G+C content of 45.67%.

  1. Draft Genome Sequence of Nafulsella turpanensis ZLM-10T, a Novel Member of the Family Flammeovirgaceae

    OpenAIRE

    Zhang, Lei; Si, Meiru; Zhu, Lingfang; Li, Changfu; Wei, Yahong; Shen, Xihui

    2014-01-01

    Nafulsella turpanensis ZLM-10T is a slightly halophilic, Gram-negative, rod-shaped, gliding, pale-pink-pigmented bacterium in the family Flammeovirgaceae, and it shows resistance to gentamicin, kanamycin, neomycin, and streptomycin. Here, we report the genome sequence of N. turpanensis strain ZLM-10T, which has a 4.8-Mb genome and a G+C content of 45.67%.

  2. Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L.) on Two Gram-Negative and Gram-Positive Bacteria

    Science.gov (United States)

    Biswas, Bipul; Rogers, Kimberly; McLaughlin, Fredrick; Yadav, Anand

    2013-01-01

    Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50 μL leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3 mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0 mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties. PMID:24223039

  3. Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L. on Two Gram-Negative and Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Bipul Biswas

    2013-01-01

    Full Text Available Aim. To determine the antimicrobial potential of guava (Psidium guajava leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water. The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50 μL leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3 mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0 mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties.

  4. Salty sisters: The women of halophiles

    Directory of Open Access Journals (Sweden)

    Bonnie K. Baxter

    2014-06-01

    Full Text Available A history of halophile research reveals the commitment of scientists to uncovering the secrets of the limits of life, in particular life in high salt concentration and under extreme osmotic pressure. During the last 40 years, halophile scientists have indeed made important contributions to extremophile research, and prior international halophiles congresses have documented both the historical and the current work. During this period of salty discoveries, female scientists, in general, have grown in number worldwide. But those who worked in the field when there were small numbers of women sometimes saw their important contributions overshadowed by their male counterparts. Recent studies suggest that modern female scientists experience gender bias in matters such as conference invitations and even representation among full professors. In the field of halophilic microbiology, what is the impact of gender bias? How has the participation of women changed over time? What do women uniquely contribute to this field? What are factors that impact current female scientists to a greater degree? This essay emphasizes the herstory (not history of halophile discovery.

  5. Nicotinoprotein methanol dehydrogenase enzymes in Gram-positive methylotrophic bacteria

    NARCIS (Netherlands)

    Hektor, Harm J.; Kloosterman, Harm; Dijkhuizen, Lubbert

    2000-01-01

    A novel type of alcohol dehydrogenase enzyme has been characterized from Gram-positive methylotrophic (Bacillus methanolicus, the actinomycetes Amycolatopsis methanolica and Mycobacterium gastri) and non-methylotrophic bacteria (Rhodococcus strains). Its in vivo role is in oxidation of methanol and

  6. Halophiles and their enzymes: Negativity put to good use

    Science.gov (United States)

    DasSarma, Shiladitya; DasSarma, Priya

    2015-01-01

    Halophilic microorganisms possess stable enzymes that function in very high salinity, an extreme condition that leads to denaturation, aggregation, and precipitation of most other proteins. Genomic and structural analyses have established that the enzymes of halophilic Archaea and many halophilic Bacteria are negatively charged due to an excess of acidic over basic residues, and altered hydrophobicity, which enhance solubility and promote function in low water activity conditions. Here, we provide an update on recent bioinformatic analysis of predicted halophilic proteomes as well as experimental molecular studies on individual halophilic enzymes. On-going efforts on discovery and utilization of halophiles and their enzymes for biotechnology, including biofuel applications are also considered. PMID:26066288

  7. Halophiles and their enzymes: negativity put to good use.

    Science.gov (United States)

    DasSarma, Shiladitya; DasSarma, Priya

    2015-06-01

    Halophilic microorganisms possess stable enzymes that function in very high salinity, an extreme condition that leads to denaturation, aggregation, and precipitation of most other proteins. Genomic and structural analyses have established that the enzymes of halophilic Archaea and many halophilic Bacteria are negatively charged due to an excess of acidic over basic residues, and altered hydrophobicity, which enhance solubility and promote function in low water activity conditions. Here, we provide an update on recent bioinformatic analysis of predicted halophilic proteomes as well as experimental molecular studies on individual halophilic enzymes. Recent efforts on discovery and utilization of halophiles and their enzymes for biotechnology, including biofuel applications are also considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. In vitro activity of daptomycin against clinical isolates of Gram-positive bacteria.

    Science.gov (United States)

    Piper, Kerryl E; Steckelberg, James M; Patel, Robin

    2005-08-01

    We determined the activity of daptomycin, a recently FDA-approved antimicrobial agent, against clinical isolates of Gram-positive bacteria, including viridans group streptococci (16 Streptococcus mitis species group, 12 S. mutans species group, 9 S. anginosus species group, 8 S. sanguinis species group, 5 S. salivarius species group) from patients with infective endocarditis, 32 methicillin-resistant Staphylococcus aureus, 32 high-level penicillin-resistant Streptococcus pneumoniae, 38 vancomycin-resistant enterococci (including 1 linezolid-resistant isolate), and the following unusual Gram-positive bacteria: 3 Listeria monocytogenes, 4 Erysipelothrix rhusiopathiae, 9 Corynebacterium species, 10 Abiotrophia/Granulicatella species, 2 Rothia (Stomatococcus) mucilaginosus, and 4 Gemella morbillorum. Daptomycin minimum inhibitory concentration (MIC)(90) values for the viridans group streptococci, methicillin-resistant S. aureus, penicillin-resistant S. pneumoniae, and Enterococcus species were 0.5, 0.5, endocarditis as well as against several types of unusual Gram-positive bacteria that can cause endocarditis.

  9. Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression

    Science.gov (United States)

    Mars, Ruben A. T.; Nicolas, Pierre; Denham, Emma L.

    2016-01-01

    SUMMARY Bacteria can employ widely diverse RNA molecules to regulate their gene expression. Such molecules include trans-acting small regulatory RNAs, antisense RNAs, and a variety of transcriptional attenuation mechanisms in the 5′ untranslated region. Thus far, most regulatory RNA research has focused on Gram-negative bacteria, such as Escherichia coli and Salmonella. Hence, there is uncertainty about whether the resulting insights can be extrapolated directly to other bacteria, such as the Gram-positive soil bacterium Bacillus subtilis. A recent study identified 1,583 putative regulatory RNAs in B. subtilis, whose expression was assessed across 104 conditions. Here, we review the current understanding of RNA-based regulation in B. subtilis, and we categorize the newly identified putative regulatory RNAs on the basis of their conservation in other bacilli and the stability of their predicted secondary structures. Our present evaluation of the publicly available data indicates that RNA-mediated gene regulation in B. subtilis mostly involves elements at the 5′ ends of mRNA molecules. These can include 5′ secondary structure elements and metabolite-, tRNA-, or protein-binding sites. Importantly, sense-independent segments are identified as the most conserved and structured potential regulatory RNAs in B. subtilis. Altogether, the present survey provides many leads for the identification of new regulatory RNA functions in B. subtilis. PMID:27784798

  10. Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression.

    Science.gov (United States)

    Mars, Ruben A T; Nicolas, Pierre; Denham, Emma L; van Dijl, Jan Maarten

    2016-12-01

    Bacteria can employ widely diverse RNA molecules to regulate their gene expression. Such molecules include trans-acting small regulatory RNAs, antisense RNAs, and a variety of transcriptional attenuation mechanisms in the 5' untranslated region. Thus far, most regulatory RNA research has focused on Gram-negative bacteria, such as Escherichia coli and Salmonella. Hence, there is uncertainty about whether the resulting insights can be extrapolated directly to other bacteria, such as the Gram-positive soil bacterium Bacillus subtilis. A recent study identified 1,583 putative regulatory RNAs in B. subtilis, whose expression was assessed across 104 conditions. Here, we review the current understanding of RNA-based regulation in B. subtilis, and we categorize the newly identified putative regulatory RNAs on the basis of their conservation in other bacilli and the stability of their predicted secondary structures. Our present evaluation of the publicly available data indicates that RNA-mediated gene regulation in B. subtilis mostly involves elements at the 5' ends of mRNA molecules. These can include 5' secondary structure elements and metabolite-, tRNA-, or protein-binding sites. Importantly, sense-independent segments are identified as the most conserved and structured potential regulatory RNAs in B. subtilis. Altogether, the present survey provides many leads for the identification of new regulatory RNA functions in B. subtilis. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. Diesel degradation and biosurfactant production by Gram-positive ...

    African Journals Online (AJOL)

    The ability of Gram-positive bacteria to degrade diesel increased in a comparable trend as its biosurfactant production increased. The E24 index was highest at 87.6% for isolate D9. Isolates D2, D9 and D10, were identified as Paenibacillus sp. whilst isolate DJLB was found to belong to Stenotrophomonas sp. This study ...

  12. Multi-location gram-positive and gram-negative bacterial protein subcellular localization using gene ontology and multi-label classifier ensemble.

    Science.gov (United States)

    Wang, Xiao; Zhang, Jun; Li, Guo-Zheng

    2015-01-01

    It has become a very important and full of challenge task to predict bacterial protein subcellular locations using computational methods. Although there exist a lot of prediction methods for bacterial proteins, the majority of these methods can only deal with single-location proteins. But unfortunately many multi-location proteins are located in the bacterial cells. Moreover, multi-location proteins have special biological functions capable of helping the development of new drugs. So it is necessary to develop new computational methods for accurately predicting subcellular locations of multi-location bacterial proteins. In this article, two efficient multi-label predictors, Gpos-ECC-mPLoc and Gneg-ECC-mPLoc, are developed to predict the subcellular locations of multi-label gram-positive and gram-negative bacterial proteins respectively. The two multi-label predictors construct the GO vectors by using the GO terms of homologous proteins of query proteins and then adopt a powerful multi-label ensemble classifier to make the final multi-label prediction. The two multi-label predictors have the following advantages: (1) they improve the prediction performance of multi-label proteins by taking the correlations among different labels into account; (2) they ensemble multiple CC classifiers and further generate better prediction results by ensemble learning; and (3) they construct the GO vectors by using the frequency of occurrences of GO terms in the typical homologous set instead of using 0/1 values. Experimental results show that Gpos-ECC-mPLoc and Gneg-ECC-mPLoc can efficiently predict the subcellular locations of multi-label gram-positive and gram-negative bacterial proteins respectively. Gpos-ECC-mPLoc and Gneg-ECC-mPLoc can efficiently improve prediction accuracy of subcellular localization of multi-location gram-positive and gram-negative bacterial proteins respectively. The online web servers for Gpos-ECC-mPLoc and Gneg-ECC-mPLoc predictors are freely accessible

  13. [Experimental interaction of halophilic prokaryotes and opportunistic bacteria in brine].

    Science.gov (United States)

    Selivanova, E A; Nemtseva, N V

    2013-01-01

    Study the effect of extremely halophilic archaea and moderately halophilic bacteria on preservation of opportunistic bacteria in brine. 17 strains of moderately halophilic bacteria and 2 strains of extremely halophilic archaea were isolated from continental hypersaline lake Razval of Sol-Iletsk area of Orenburg Region. Identification of pure cultures of prokaryotes was carried out taking into account their phenotype properties and based on determination of 16S RNA gene sequence. The effect of halophilic prokaryote on elimination of Escherichia coli from brine was evaluated during co-cultivation. Antagonistic activity of cell extracts of the studied microorganisms was evaluated by photometric method. A more prolonged preservation of an E. coli strain in brine in the presence of live cells of extremely halophilic archaea Halorubrum tebenquichense and moderately halophilic bacteria Marinococcus halophilus was established. Extracts of cells of extremely halophilic archaea and moderately halophilic bacteria on the contrary displayed antagonistic activity. The protective effect of live cells of halophilic prokaryotes and antagonistic activity of their cell extracts change the period of conservation of opportunistic bacteria in brine that regulates inter-microbial interactions and changes the period of self-purification that reflects the sanitary condition of a hypersaline water body.

  14. Endocarditis : Effects of routine echocardiography during Gram-positive bacteraemia

    NARCIS (Netherlands)

    Vos, F J; Bleeker-Rovers, C P; Sturm, P D; Krabbe, P F M; van Dijk, A P J; Oyen, W J G; Kullberg, B J

    2011-01-01

    BACKGROUND: Despite firm recommendations to perform echocardiography in high-risk patients with Gram-positive bacteraemia, routine echocardiography is not embedded in daily practice in many settings. The aim of this study was to evaluate whether a regime including routine echocardiography results in

  15. Linezolid: a promising option in the treatment of Gram-positives.

    Science.gov (United States)

    Zahedi Bialvaei, Abed; Rahbar, Mohammad; Yousefi, Mehdi; Asgharzadeh, Mohammad; Samadi Kafil, Hossein

    2017-02-01

    Linezolid, an oxazolidinone antimicrobial agent that acts by inhibiting protein synthesis in a unique fashion, is used in the treatment of community-acquired pneumonia, skin and soft-tissue infections and other infections caused by Gram-positive bacteria including VRE and methicillin-resistant staphylococci. Currently, linezolid resistance among these pathogens remains low, commonly linezolid susceptibility testing for this important agent and should be taken into account when considering its therapeutic use. Considering the importance of linezolid in the treatment of infections caused by Gram-positive bacteria, this review was undertaken to optimize the clinical use of this antibiotic. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Microbiological Synthesis of 2H-Labeled Phenylalanine, Alanine, Valine, and Leucine/Isoleucine with Different Degrees of Deuterium Enrichment by the Gram-Positive Facultative Methylotrophic Bacterium Вrevibacterium Methylicum

    Directory of Open Access Journals (Sweden)

    Oleg V. Mosin, PhD¹

    2013-06-01

    Full Text Available The microbiological synthesis of [2H]amino acids was performed by the conversion of low molecular weight substrates ([U-2H]MeOH and 2H2O using the Gram-positive aerobic facultative methylotrophic bacterium Brevibacterium methylicum, an L-phenylalanine producer, realizing the NAD+ dependent methanol dehydrogenase (EC 1.6.99.3 variant of the ribulose-5-monophosphate (RuMP cycle of carbon assimilation. In this process, the adapted cells of the methylotroph with enhanced growth characteristics were used on a minimal salt medium M9, supplemented with 2% (v/v [U-2H]MeOH and an increasing gradient of 2Н2O concentration from 0; 24.5, 49.0; 73.5 up to 98% (v/v 2Н2O. Alanine, valine, and leucine/isoleucine were produced and accumulated exogeneously in quantities of 5–6 mol, in addition to the main product of biosynthesis. This method enables the production of [2Н]amino acids with different degrees of deuterium enrichment, depending on the 2Н2O concentration in the growth medium, from 17 at.% 2Н (on the growth medium with 24.5 % (v/v 2Н2О up to 75 at.% 2Н (on the growth medium with 98 % (v/v 2Н2О. This has been confirmed with the data from the electron impact (EI mass spectrometry analysis of the methyl ethers of N-dimethylamino(naphthalene-5-sulfochloride [2H]amino acids under these experimental conditions.

  17. Fighting infections due to multidrug-resistant Gram-positive pathogens.

    Science.gov (United States)

    Cornaglia, G

    2009-03-01

    Growing bacterial resistance in Gram-positive pathogens means that what were once effective and inexpensive treatments for infections caused by these bacteria are now being seriously questioned, including penicillin and macrolides for use against pneumococcal infections and-in hospitals-oxacillin for use against staphylococcal infections. As a whole, multidrug-resistant (MDR) Gram-positive pathogens are rapidly becoming an urgent and sometimes unmanageable clinical problem. Nevertheless, and despite decades of research into the effects of antibiotics, the actual risk posed to human health by antibiotic resistance has been poorly defined; the lack of reliable data concerning the outcomes resulting from antimicrobial resistance stems, in part, from problems with study designs and the methods used in resistence determination. Surprisingly little is known, too, about the actual effectiveness of the many types of intervention aimed at controlling antibiotic resistance. New antibiotics active against MDR Gram-positive pathogens have been recently introduced into clinical practice, and the antibiotic pipeline contains additional compounds at an advanced stage of development, including new glycopeptides, new anti-methicillin-resistant Staphylococcus aureus (MRSA) beta-lactams, and new diaminopyrimidines. Many novel antimicrobial agents are likely to be niche products, endowed with narrow antibacterial spectra and/or targeted at specific clinical problems. Therefore, an important educational goal will be to change the current, long-lasting attitudes of both physicians and customers towards broad-spectrum and multipurpose compounds. Scientific societies, such as the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), must play a leading role in this process.

  18. Gram staining.

    Science.gov (United States)

    Coico, Richard

    2005-10-01

    Named after Hans Christian Gram who developed the method in 1884, the Gram stain allows one to distinguish between Gram-positive and Gram-negative bacteria on the basis of differential staining with a crystal violet-iodine complex and a safranin counterstain. The cell walls of Gram-positive organisms retain this complex after treatment with alcohol and appear purple, whereas gram-negative organisms decolorize following such treatment and appear pink. The method described here is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures.

  19. Magnesium and manganese content of halophilic bacteria

    International Nuclear Information System (INIS)

    de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

    1986-01-01

    Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

  20. Rapid and reliable identification of Gram-negative bacteria and Gram-positive cocci by deposition of bacteria harvested from blood cultures onto the MALDI-TOF plate.

    Science.gov (United States)

    Barnini, Simona; Ghelardi, Emilia; Brucculeri, Veronica; Morici, Paola; Lupetti, Antonella

    2015-06-18

    Rapid identification of the causative agent(s) of bloodstream infections using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) methodology can lead to increased empirical antimicrobial therapy appropriateness. Herein, we aimed at establishing an easier and simpler method, further referred to as the direct method, using bacteria harvested by serum separator tubes from positive blood cultures and placed onto the polished steel target plate for rapid identification by MALDI-TOF. The results by the direct method were compared with those obtained by MALDI-TOF on bacteria isolated on solid media. Identification of Gram-negative bacilli was 100 % concordant using the direct method or MALDI-TOF on isolated bacteria (96 % with score > 2.0). These two methods were 90 % concordant on Gram-positive cocci (32 % with score > 2.0). Identification by the SepsiTyper method of Gram-positive cocci gave concordant results with MALDI-TOF on isolated bacteria in 87 % of cases (37 % with score > 2.0). The direct method herein developed allows rapid identification (within 30 min) of Gram-negative bacteria and Gram-positive cocci from positive blood cultures and can be used to rapidly report reliable and accurate results, without requiring skilled personnel or the use of expensive kits.

  1. Uranium association with halophilic and non-halophilic bacteria and archaea

    International Nuclear Information System (INIS)

    Francis, A.J.; Gillow, J.B.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Papenguth, H.W.

    2004-01-01

    We determined the association of uranium with bacteria isolated from the Waste Isolation Pilot Plant (WIPP), Carlsbad, New Mexico, and compared this with known strains of halophilic and non-halophilic bacteria and archaea. Examination of the cultures by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) showed uranium accumulation extracellularly and/or intracellularly to a varying degree. In Pseudomonas fluorescens and Bacillus subtilis uranium was associated with the cell surface and in the latter it was present as irregularly shaped grains. In Halobacterium halobium, the only archeon studied here, uranium was present as dense deposits and with Haloanaerobium praevalens as spikey deposits. Halomonas sp. isolated from the WIPP site accumulated uranium both extracellularly on the cell surface and intracellularly as electron-dense discrete granules. Extended X-ray absorption fine structure (EXAFS) analysis of uranium with the halophilic and non-halophilic bacteria and archaea showed that the uranium present in whole cells was bonded to an average of 2.4 ± 0.7 phosphoryl groups at a distance of 3.65 ± 0.03 Aa. Comparison of whole cells of Halomonas sp. with the cell wall fragments of lysed cells showed the presence of a uranium bidentate complex at 2.91 ± 0.03 Aa with the carboxylate group on the cell wall, and uranyl hydroxide with U-U interaction at 3.71 ± 0.03 Aa due to adsorption or precipitation reactions; no U-P interaction was observed. Addition of uranium to the cell lysate of Halomonas sp. resulted in the precipitation of uranium due to the inorganic phosphate produced by the cells. These results show that the phosphates released from bacteria bind a significant amount of uranium. However, the bacterially immobilized uranium was readily solubilized by bicarbonate with concurrent release of phosphate into solution. (orig.)

  2. Expression of a Clostridium perfringens genome-encoded putative N-acetylmuramoyl-L-alanine amidase as a potential antimicrobial to control the bacterium

    Science.gov (United States)

    Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium that plays a substantial role in non-foodborne human, animal and avian diseases as well as human foodborne disease. Previously discovered C. perfringens bacteriophage lytic enzyme amino acid sequences were utilized to iden...

  3. Actinide Biocolloid Formation in Brine by Halophilic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Gillow, J.B.; Francis, A.J.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Brady, P.V.; Papenguth, H.W.

    1999-07-28

    We examined the ability of a halophilic bacterium (WFP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell Surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited volubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellulary as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis, of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide.

  4. Actinide biocolloid formation in brine by halophilic bacteria

    International Nuclear Information System (INIS)

    Gillow, J.B.; Francis, A.J.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Brady, P.B.; Papenguth, H.W.

    1998-01-01

    The authors examined the ability of a halophilic bacterium (WIPP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited solubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellularly as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide

  5. Actinide biocolloid formation in brine by halophilic bacteria

    International Nuclear Information System (INIS)

    Gillow, J.B.; Francis, A.J.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Brady, P.V.; Papenguth, H.W.

    1999-01-01

    The authors examined the ability of a halophilic bacterium (WIPP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited solubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellularly as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide

  6. Actinide Biocolloid Formation in Brine by Halophilic Bacteria

    International Nuclear Information System (INIS)

    Gillow, J.B.; Francis, A.J.; Dodge, C.J.; Harris, R.; Beveridge, T.J.; Brady, P.V.; Papenguth, H.W.

    1999-01-01

    We examined the ability of a halophilic bacterium (WFP 1A) isolated from the Waste Isolation Pilot Plant (WIPP) site to accumulate uranium in order to determine the potential for biocolloid facilitated actinide transport. The bacterial cell Surface functional groups involved in the complexation of the actinide were determined by titration. Uranium, added as uranyl nitrate, was removed from solution at pH 5 by cells but at pH 7 and 9 very little uranium was removed due to its limited volubility. Although present as soluble species, uranyl citrate at pH 5, 7, and 9, and uranyl carbonate at pH 9 were not removed by the bacterium because they were not bioavailable due to their neutral or negative charge. Addition of uranyl EDTA to brine at pH 5, 7, and 9 resulted in the immediate precipitation of U. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis revealed that uranium was not only associated with the cell surface but also accumulated intracellulary as uranium-enriched granules. Extended X-ray absorption fine structure (EXAFS) analysis, of the bacterial cells indicated the bulk sample contained more than one uranium phase. Nevertheless these results show the potential for the formation of actinide bearing bacterial biocolloids that are strictly regulated by the speciation and bioavailability of the actinide

  7. Cytokine profile in severe gram-positive and gram-negative abdominal sepsis

    Science.gov (United States)

    Surbatovic, Maja; Popovic, Nada; Vojvodic, Danilo; Milosevic, Ivan; Acimovic, Gordana; Stojicic, Milan; Veljovic, Milic; Jevdjic, Jasna; Djordjevic, Dragan; Radakovic, Sonja

    2015-01-01

    Sepsis is a principal cause of death in critical care units worldwide and consumes considerable healthcare resources. The aim of our study was to determine whether the early cytokine profile can discriminate between Gram-positive and Gram-negative bacteraemia (GPB and GNB, respectively) and to assess the prognostic value regarding outcome in critically ill patients with severe abdominal sepsis. The outcome measure was hospital mortality. Blood samples were obtained from 165 adult patients with confirmed severe abdominal sepsis. Levels of the proinflammatory mediators TNF-α, IL-8, IL-12 and IFN-γ and the anti-inflammatory mediators IL-1ra, IL-4, IL-10 and TGF-β1 were determined and correlated with the nature of the bacteria isolated from the blood culture and outcome. The cytokine profile in our study indicated that the TNF-α levels were 2-fold, IL-8 were 3.3-fold, IFN-γ were 13-fold, IL-1ra were 1.05-fold, IL-4 were 1.4-fold and IL-10 were 1.83-fold higher in the GNB group compared with the GPB group. The TNF-α levels were 4.7-fold, IL-8 were 4.6-fold, IL-1ra were 1.5-fold and IL-10 were 3.3-fold higher in the non-survivors compared with the survivors. PMID:26079127

  8. Salt-bridge energetics in halophilic proteins.

    Science.gov (United States)

    Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K

    2014-01-01

    Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its

  9. Untargeted Metabolomics Approach in Halophiles: Understanding the Biodeterioration Process of Building Materials

    Directory of Open Access Journals (Sweden)

    Justyna Adamiak

    2017-12-01

    Full Text Available The aim of the study was to explore the halophile metabolome in building materials using untargeted metabolomics which allows for broad metabolome coverage. For this reason, we used high-performance liquid chromatography interfaced to high-resolution mass spectrometry (HPLC/HRMS. As an alternative to standard microscopy techniques, we introduced pioneering Coherent Anti-stokes Raman Scattering Microscopy (CARS to non-invasively visualize microbial cells. Brick samples saturated with salt solution (KCl, NaCl (two salinity levels, MgSO4, Mg(NO32, were inoculated with the mixture of preselected halophilic microorganisms, i.e., bacteria: Halobacillus styriensis, Halobacillus naozhouensis, Halobacillus hunanensis, Staphylococcus succinus, Marinococcus halophilus, Virgibacillus halodenitryficans, and yeast: Sterigmatomyces halophilus and stored at 28°C and 80% relative humidity for a year. Metabolites were extracted directly from the brick samples and measured via HPLC/HRMS in both positive and negative ion modes. Overall, untargeted metabolomics allowed for discovering the interactions of halophilic microorganisms with buildings materials which together with CARS microscopy enabled us to elucidate the biodeterioration process caused by halophiles. We observed that halophile metabolome was differently affected by different salt solutions. Furthermore, we found indications for haloadaptive strategies and degradation of brick samples due to microbial pigment production as a salt stress response. Finally, we detected changes in lipid content related to changes in the structure of phospholipid bilayers and membrane fluidity.

  10. Associations of Eu(III) with Gram-negative bacteria, Alcaligenes faecalis, Shewanella putrefaciens, and Paracoccus denitrificans

    International Nuclear Information System (INIS)

    Ozaki, Takuo; Ohnuki, Toshihiko; Kimura, Takaumi; Francis, Arokiasamy J.

    2005-01-01

    We studied the association of Eu(III) with Gram-negative bacteria, Alcaligenes faecalis, Shewanella putrefaciens, and Paracoccus denitrificans by a batch method and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The kinetics study showed that the Eu(III) adsorption on the bacteria rapidly proceeded. The Eu(III) adsorption on A. faecalis and P. denitrificans at pHs 3, 4, and 5, and that on S.putrefaciens at pHs 4 and 5 reached a maximum within 5 minutes after contact. For P. denitrificans, the percent adsorption of Eu(III) decreased after the maximum percent adsorption was attained, which suggests the existence of exudates with an affinity with Eu(III). TRLFS showed that the coordination of Eu(III) on these bacteria is multidentate through an inner-spherical process. The ligand field of Eu(III) on P. denitrificans was as strong as the ones observed for halophilic microorganisms, while that of A. faecalis and S. putrefaciens was the typical one observed for non-halophilic microorganisms. The coordination environment of Eu(III) on the bacteria differed from each other, though they are categorized as Gram-negative bacteria with the similar cell wall components. (author)

  11. The Function of Gas Vesicles in Halophilic Archaeaand Bacteria: Theories and Experimental Evidence

    Science.gov (United States)

    Oren, Aharon

    2012-01-01

    A few extremely halophilic Archaea (Halobacterium salinarum, Haloquadratum walsbyi, Haloferax mediterranei, Halorubrum vacuolatum, Halogeometricum borinquense, Haloplanus spp.) possess gas vesicles that bestow buoyancy on the cells. Gas vesicles are also produced by the anaerobic endospore-forming halophilic Bacteria Sporohalobacter lortetii and Orenia sivashensis. We have extensive information on the properties of gas vesicles in Hbt. salinarum and Hfx. mediterranei and the regulation of their formation. Different functions were suggested for gas vesicle synthesis: buoying cells towards oxygen-rich surface layers in hypersaline water bodies to prevent oxygen limitation, reaching higher light intensities for the light-driven proton pump bacteriorhodopsin, positioning the cells optimally for light absorption, light shielding, reducing the cytoplasmic volume leading to a higher surface-area-to-volume ratio (for the Archaea) and dispersal of endospores (for the anaerobic spore-forming Bacteria). Except for Hqr. walsbyi which abounds in saltern crystallizer brines, gas-vacuolate halophiles are not among the dominant life forms in hypersaline environments. There only has been little research on gas vesicles in natural communities of halophilic microorganisms, and the few existing studies failed to provide clear evidence for their possible function. This paper summarizes the current status of the different theories why gas vesicles may provide a selective advantage to some halophilic microorganisms. PMID:25371329

  12. Amplifiable DNA from Gram-negative and Gram-positive bacteria by a low strength pulsed electric field method

    Science.gov (United States)

    Vitzthum, Frank; Geiger, Georg; Bisswanger, Hans; Elkine, Bentsian; Brunner, Herwig; Bernhagen, Jürgen

    2000-01-01

    An efficient electric field-based procedure for cell disruption and DNA isolation is described. Isoosmotic suspensions of Gram-negative and Gram-positive bacteria were treated with pulsed electric fields of Pulses had an exponential decay waveform with a time constant of 3.4 µs. DNA yield was linearly dependent on time or pulse number, with several thousand pulses needed. Electrochemical side-effects and electrophoresis were minimal. The lysates contained non-fragmented DNA which was readily amplifiable by PCR. As the method was not limited to samples of high specific resistance, it should be applicable to physiological fluids and be useful for genomic and DNA diagnostic applications. PMID:10734214

  13. A Synthetic Dual Drug Sideromycin Induces Gram-Negative Bacteria To Commit Suicide with a Gram-Positive Antibiotic.

    Science.gov (United States)

    Liu, Rui; Miller, Patricia A; Vakulenko, Sergei B; Stewart, Nichole K; Boggess, William C; Miller, Marvin J

    2018-05-10

    Many antibiotics lack activity against Gram-negative bacteria because they cannot permeate the outer membrane or suffer from efflux and, in the case of β-lactams, are degraded by β-lactamases. Herein, we describe the synthesis and studies of a dual drug conjugate (1) of a siderophore linked to a cephalosporin with an attached oxazolidinone. The cephalosporin component of 1 is rapidly hydrolyzed by purified ADC-1 β-lactamase to release the oxazolidinone. Conjugate 1 is active against clinical isolates of Acinetobacter baumannii as well as strains producing large amounts of ADC-1 β-lactamase. Overall, the results are consistent with siderophore-mediated active uptake, inherent activity of the delivered dual drug, and in the presence of β-lactamases, intracellular release of the oxazolidinone upon cleavage of the cephalosporin to allow the freed oxazolidinone to inactivate its target. The ultimate result demonstrates that Gram-positive oxazolidinone antibiotics can be made to be effective against Gram-negative bacteria by β-lactamase triggered release.

  14. Optimization of EPS Production and Characterization by a Halophilic Bacterium, Kocuria rosea ZJUQH from Chaka Salt Lake with Response Surface Methodology.

    Science.gov (United States)

    Gu, Di; Jiao, Yingchun; Wu, Jianan; Liu, Zhengjie; Chen, Qihe

    2017-05-16

    With the rising awareness of microbial exopolysaccharides (EPSs) application in various fields, halophilic microorganisms which produce EPSs have received broad attention. A newly identified Kocuria rosea ZJUQH CCTCC M2016754 was determined to be a moderate halobacterium on account of its successful adaption to the environment containing 10% NaCl. The optimal combination of fermentation medium compositions on EPS production was studied. In this work, a fractional factorial design was adopted to investigate the significant factors that affected EPS production. The factors of KCl and MgSO₄ were found to have a profound impact on EPS production. We utilized central composite design and response surface methodology to derive a statistical model for optimizing the submerged culture medium composition. Judging from these experimental results, the optimum culture medium for producing EPSs was composed of 0.50% casein hydrolysate, 1.00% sodium citrate, 0.30% yeast extract, 0.50% KCl, 0.50% peptone, and 5.80% MgSO₄ (initial pH 7.0). The maximal EPS was 48.01 g/L, which is close to the predicted value (50.39 g/L). In the validation experiment, the highest concentration of 70.64 g/L EPSs was obtained after 120 h under the optimized culture medium in a 5-L bioreactor. EPS from this bacterium was also characterized by differential scanning calorimetry (DSC) and Fourier transform infrared analysis (FT-IR). The findings in this study imply that Kocuria rosea ZJUQH has great potential to be exploited as a source of EPSs utilized in food, the pharmaceutical and agriculture industry, and in the biotreatment of hypersaline environments.

  15. Comparative activity of tigecycline and tetracycline on Gram-negative and Gram-positive bacteria revealed by a multicentre study in four North European countries

    DEFF Research Database (Denmark)

    Nilsson, Lennart E; Frimodt-Møller, Niels; Vaara, Martti

    2011-01-01

    This study involves a multicentre surveillance of tigecycline and tetracycline activity against Gram-negative and Gram-positive bacteria from primary care centres (PCCs), general hospital wards (GHWs) and intensive care units (ICUs) in Denmark (n = 9), Finland (n = 10), Norway (n = 7) and Sweden (n...

  16. Isolation of an unidentified pink-pigmented bacterium in a clinical specimen.

    OpenAIRE

    Odugbemi, T; Nwofor, C; Joiner, K T

    1988-01-01

    An unidentified pink-pigmented bacterium isolated from a clinical specimen is reported. The organism was oxidase, urease, and catalase positive; it grew on Thayer-Martin and MacConkey media. The isolate is possibly similar to an unnamed taxon (G.L. Gilardi and Y.C. Faur, J. Clin. Microbiol. 20:626-629, 1984); however, it had unique characteristics of nonmotility with no flagellum detectable and was a gram-negative coccoid with a few rods in pairs and negative for starch hydrolysis.

  17. Isolation of an unidentified pink-pigmented bacterium in a clinical specimen.

    Science.gov (United States)

    Odugbemi, T; Nwofor, C; Joiner, K T

    1988-05-01

    An unidentified pink-pigmented bacterium isolated from a clinical specimen is reported. The organism was oxidase, urease, and catalase positive; it grew on Thayer-Martin and MacConkey media. The isolate is possibly similar to an unnamed taxon (G.L. Gilardi and Y.C. Faur, J. Clin. Microbiol. 20:626-629, 1984); however, it had unique characteristics of nonmotility with no flagellum detectable and was a gram-negative coccoid with a few rods in pairs and negative for starch hydrolysis.

  18. Systematic and biotechnological aspects of halophilic and halotolerant actinomycetes.

    Science.gov (United States)

    Hamedi, Javad; Mohammadipanah, Fatemeh; Ventosa, Antonio

    2013-01-01

    More than 70 species of halotolerant and halophilic actinomycetes belonging to at least 24 genera have been validly described. Halophilic actinomycetes are a less explored source of actinomycetes for discovery of novel bioactive secondary metabolites. Degradation of aliphatic and aromatic organic compounds, detoxification of pollutants, production of new enzymes and other metabolites such as antibiotics, compatible solutes and polymers are other potential industrial applications of halophilic and halotolerant actinomycetes. Especially new bioactive secondary metabolites that are derived from only a small fraction of the investigated halophilic actinomycetes, mainly from marine habitats, have revealed the huge capacity of this physiological group in production of new bioactive chemical entities. Combined high metabolic capacities of actinomycetes and unique features related to extremophilic nature of the halophilic actinomycetes have conferred on them an influential role for future biotechnological applications.

  19. Screening and isolation of halophilic bacteria producing industrially important enzymes.

    Science.gov (United States)

    Kumar, Sumit; Karan, Ram; Kapoor, Sanjay; S P, Singh; S K, Khare

    2012-10-01

    Halophiles are excellent sources of enzymes that are not only salt stable but also can withstand and carry out reactions efficiently under extreme conditions. The aim of the study was to isolate and study the diversity among halophilic bacteria producing enzymes of industrial value. Screening of halophiles from various saline habitats of India led to isolation of 108 halophilic bacteria producing industrially important hydrolases (amylases, lipases and proteases). Characterization of 21 potential isolates by morphological, biochemical and 16S rRNA gene analysis found them related to Marinobacter, Virgibacillus, Halobacillus, Geomicrobium, Chromohalobacter, Oceanobacillus, Bacillus, Halomonas and Staphylococcus genera. They belonged to moderately halophilic group of bacteria exhibiting salt requirement in the range of 3-20%. There is significant diversity among halophiles from saline habitats of India. Preliminary characterization of crude hydrolases established them to be active and stable under more than one extreme condition of high salt, pH, temperature and presence of organic solvents. It is concluded that these halophilic isolates are not only diverse in phylogeny but also in their enzyme characteristics. Their enzymes may be potentially useful for catalysis under harsh operational conditions encountered in industrial processes. The solvent stability among halophilic enzymes seems a generic novel feature making them potentially useful in non-aqueous enzymology.

  20. Stability of halophilic proteins: from dipeptide attributes to discrimination classifier.

    Science.gov (United States)

    Zhang, Guangya; Huihua, Ge; Yi, Lin

    2013-02-01

    To investigate the molecular features responsible for protein halophilicity is of great significance for understanding the structure basis of protein halo-stability and would help to develop a practical strategy for designing halophilic proteins. In this work, we have systematically analyzed the dipeptide composition of the halophilic and non-halophilic protein sequences. We observed the halophilic proteins contained more DA, RA, AD, RR, AP, DD, PD, EA, VG and DV at the expense of LK, IL, II, IA, KK, IS, KA, GK, RK and AI. We identified some macromolecular signatures of halo-adaptation, and thought the dipeptide composition might contain more information than amino acid composition. Based on the dipeptide composition, we have developed a machine learning method for classifying halophilic and non-halophilic proteins for the first time. The accuracy of our method for the training dataset was 100.0%, and for the 10-fold cross-validation was 93.1%. We also discussed the influence of some specific dipeptides on prediction accuracy. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Insights into the extremotolerance of Acinetobacter radioresistens 50v1, a gram-negative bacterium isolated from the Mars Odyssey spacecraft.

    Science.gov (United States)

    McCoy, K B; Derecho, I; Wong, T; Tran, H M; Huynh, T D; La Duc, M T; Venkateswaran, K; Mogul, R

    2012-09-01

    The microbiology of the spacecraft assembly process is of paramount importance to planetary exploration, as the biological contamination that can result from remote-enabled spacecraft carries the potential to impact both life-detection experiments and extraterrestrial evolution. Accordingly, insights into the mechanisms and range of extremotolerance of Acinetobacter radioresistens 50v1, a Gram-negative bacterium isolated from the surface of the preflight Mars Odyssey orbiter, were gained by using a combination of microbiological, enzymatic, and proteomic methods. In summary, A. radioresistens 50v1 displayed a remarkable range of survival against hydrogen peroxide and the sequential exposures of desiccation, vapor and plasma phase hydrogen peroxide, and ultraviolet irradiation. The survival is among the highest reported for non-spore-forming and Gram-negative bacteria and is based upon contributions from the enzyme-based degradation of H(2)O(2) (catalase and alkyl hydroperoxide reductase), energy management (ATP synthase and alcohol dehydrogenase), and modulation of the membrane composition. Together, the biochemical and survival features of A. radioresistens 50v1 support a potential persistence on Mars (given an unintended or planned surface landing of the Mars Odyssey orbiter), which in turn may compromise the scientific integrity of future life-detection missions.

  2. Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle

    Science.gov (United States)

    Dubuffet, Aurore; Zanchi, Caroline; Boutet, Gwendoline; Moreau, Jérôme; Teixeira, Maria; Moret, Yannick

    2015-01-01

    In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called “Trans-generational immune priming” (TGIP) are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations. PMID:26430786

  3. Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle.

    Directory of Open Access Journals (Sweden)

    Aurore Dubuffet

    2015-10-01

    Full Text Available In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called "Trans-generational immune priming" (TGIP are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations.

  4. Subcellular localization for Gram positive and Gram negative bacterial proteins using linear interpolation smoothing model.

    Science.gov (United States)

    Saini, Harsh; Raicar, Gaurav; Dehzangi, Abdollah; Lal, Sunil; Sharma, Alok

    2015-12-07

    Protein subcellular localization is an important topic in proteomics since it is related to a protein׳s overall function, helps in the understanding of metabolic pathways, and in drug design and discovery. In this paper, a basic approximation technique from natural language processing called the linear interpolation smoothing model is applied for predicting protein subcellular localizations. The proposed approach extracts features from syntactical information in protein sequences to build probabilistic profiles using dependency models, which are used in linear interpolation to determine how likely is a sequence to belong to a particular subcellular location. This technique builds a statistical model based on maximum likelihood. It is able to deal effectively with high dimensionality that hinders other traditional classifiers such as Support Vector Machines or k-Nearest Neighbours without sacrificing performance. This approach has been evaluated by predicting subcellular localizations of Gram positive and Gram negative bacterial proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Daptomycin: a novel lipopeptide antibiotic against Gram-positive pathogens

    Directory of Open Access Journals (Sweden)

    Andres Beiras-Fernandez

    2010-08-01

    Full Text Available Andres Beiras-Fernandez1,*, Ferdinand Vogt1,*, Ralf Sodian1, Florian Weis21Department of Cardiac Surgery, University Hospital Großhadern, Ludwig-Maximilian-University, Munich, Germany; 2Department of Anesthesiology, University Hospital Großhadern, Ludwig-Maximilian-University, Munich, Germany *Andres Beiras-Fernandez and Ferdinand Vogt contributed equally to this paperAbstract: The aim of this review is to summarize the historical background of drug resistance of Gram-positive pathogens as well as to describe in detail the novel lipopeptide antibiotic daptomycin. Pharmacological and pharmacokinetic aspects are reviewed and the current clinical use of daptomycin is presented. Daptomycin seems to be a reliable drug in the treatment of complicated skin and skin structure infections, infective right-sided endocarditis, and bacteremia caused by Gram-positive agents. Its unique mechanism of action and its low resistance profile, together with its rapid bactericidal action make it a favorable alternative to vancomycin in multi-drug resistant cocci. The role of daptomycin in the treatment of prosthetic material infections, osteomyelitis, and urogenital infections needs to be evaluated in randomized clinical trials.Keywords: daptomycin, multi-drug resistance, methicillin-resistant Staphylococcus aureus (MRSA, pneumonia, urinary tract infection, left-sided endocarditis

  6. Tribolium castaneum defensins are primarily active against Gram-positive bacteria

    Czech Academy of Sciences Publication Activity Database

    Tonk, M.; Knorr, E.; Cabezas-Cruz, A.; Valdés, James J.; Kollewe, C.; Vilcinskas, A.

    2015-01-01

    Roč. 132, NOV 2015 (2015), s. 208-215 ISSN 0022-2011 R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : Antimicrobial peptides * Defensin * Innate immunity * Insects * Tribolium castaneum * Gram-positive bacteria Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.198, year: 2015

  7. European surveillance study on antimicrobial susceptibility of Gram-positive anaerobic cocci

    DEFF Research Database (Denmark)

    Brazier, J; Chmelar, D; Dubreuil, L

    2008-01-01

    Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of microorganisms frequently isolated from local and systemic infections. In this study, the antimicrobial susceptibilities of clinical strains isolated in 10 European countries were investigated. After identification of 299 GPAC...

  8. Outcomes of single organism peritonitis in peritoneal dialysis: gram negatives versus gram positives in the Network 9 Peritonitis Study.

    Science.gov (United States)

    Bunke, C M; Brier, M E; Golper, T A

    1997-08-01

    The use of the "peritonitis rate" in the management of patients undergoing peritoneal dialysis is assuming importance in comparing the prowess of facilities, care givers and new innovations. For this to be a meaningful outcome measure, the type of infection (causative pathogen) must have less clinical significance than the number of infections during a time interval. The natural history of Staphylococcus aureus, pseudomonas, and fungal peritonitis would not support that the outcome of an episode of peritonitis is independent of the causative pathogen. Could this concern be extended to other more frequently occurring pathogens? To address this, the Network 9 Peritonitis Study identified 530 episodes of single organism peritonitis caused by a gram positive organism and 136 episodes caused by a single non-pseudomonal gram negative (NPGN) pathogen. Coincidental soft tissue infections (exit site or tunnel) occurred equally in both groups. Outcomes of peritonitis were analyzed by organism classification and by presence or absence of a soft tissue infection. NPGN peritonitis was associated with significantly more frequent catheter loss, hospitalization, and technique failure and was less likely to resolve regardless of the presence or absence of a soft tissue infection. Hospitalization and death tended to occur more frequently with enterococcal peritonitis than with other gram positive peritonitis. The outcomes in the NPGN peritonitis group were significantly worse (resolution, catheter loss, hospitalization, technique failure) compared to coagulase negative staphylococcal or S. aureus peritonitis, regardless of the presence or absence of a coincidental soft tissue infection. Furthermore, for the first time, the poor outcomes of gram negative peritonitis are shown to be independent of pseudomonas or polymicrobial involvement or soft tissue infections. The gram negative organism appears to be the important factor. In addition, the outcome of peritonitis caused by S. aureus

  9. Methods for Confirming the Gram Reaction of Gram-variable Bacillus Species Isolated from Tobacco

    Directory of Open Access Journals (Sweden)

    Morin A

    2014-12-01

    Full Text Available Bacillus is a predominant genus of bacteria isolated from tobacco. The Gram stain is the most commonly used and most important of all diagnostic staining techniques in microbiology. In order to help confirm the Gram positivity of Bacillus isolates from tobacco, three methods using the chemical differences of the cell wall and membrane of Gram-positive and Gram-negative bacteria were investigated: the KOH (potassium hydroxide, the LANA (L-alanine-4-nitroanilide, and the vancomycin susceptibility tests. When colonies of Gram-negative bacteria are treated with 3% KOH solution, a slimy suspension is produced, probably due to destruction of the cell wall and liberation of deoxyribonucleic acid (DNA. Gram-positive cell walls resist KOH treatment. The LANA test reveals the presence of a cell wall aminopeptidase that hydrolyzes the L-alanine-4-nitroanilide in Gram-negative bacteria. This enzyme is absent in Gram-positive bacteria. Vancomycin is a glycopeptide antibiotic inhibiting the cell wall peptido-glycan synthesis of Gram-positive microorganisms. Absence of lysis with KOH, absence of hydrolysis of LANA, and susceptibility to vancomycin were used with the Gram reaction to confirm the Gram positivity of various Bacillus species isolated from tobacco. B. laevolacticus excepted, all Bacillus species tested showed negative reactions to KOH and LANA tests, and all species were susceptible to vancomycin (5 and 30 µg.

  10. Emergence of a New Population of Rathayibacter toxicus: An Ecologically Complex, Geographically Isolated Bacterium

    OpenAIRE

    Arif, Mohammad; Busot, Grethel Y.; Mann, Rachel; Rodoni, Brendan; Liu, Sanzhen; Stack, James P.

    2016-01-01

    Rathayibacter toxicus is a gram-positive bacterium that infects the floral parts of several Poaceae species in Australia. Bacterial ooze is often produced on the surface of infected plants and bacterial galls are produced in place of seed. R. toxicus is a regulated plant pathogen in the U.S. yet reliable detection and diagnostic tools are lacking. To better understand this geographically-isolated plant pathogen, genetic variation as a function of geographic location, host species, and date of...

  11. The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

    Directory of Open Access Journals (Sweden)

    Morroll Shaun

    2009-08-01

    Full Text Available Abstract Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins. HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as

  12. The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

    Science.gov (United States)

    Winter, Jody A; Christofi, Panayiotis; Morroll, Shaun; Bunting, Karen A

    2009-01-01

    Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA) is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA) to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins). HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as opposed to simply surviving in

  13. Optimization of linezolid treatment regimens for Gram-positive bacterial infections based on pharmacokinetic/pharmacodynamic analysis.

    Science.gov (United States)

    Yang, Minjie; Zhang, Jing; Chen, Yuancheng; Liang, Xiaoyu; Guo, Yan; Yu, Jicheng; Zhu, Demei; Zhang, Yingyuan

    2017-01-01

    To optimize linezolid treatment regimens for Gram-positive bacterial infections based on pharmacokinetic/pharmacodynamic analysis. The minimum inhibitory concentration (MIC) distribution of 572 Gram-positive strains from patients with clinically confirmed infections was analyzed. Using the Monte Carlo simulation method, the cumulative fraction of response and probability of target attainment were determined for linezolid regimens of 600 mg q.12h and q.8h Results: Linezolid dosage of 600 mg q.12h yielded >90% cumulative fraction of response and probability of target attainment for staphylococcal infections with an MIC of ≤1 mg/l, enterococcal infections with higher MIC values required 600 mg q.8h. Linezolid 600 mg q.12h is still the clinically recommended empirical dosage for Gram-positive bacterial infections. However, as bacterial MICs increase, 600 mg q.8h may be required to achieve better efficacy.

  14. Electrochemical reduction of oxygen catalyzed by a wide range of bacteria including Gram-positive

    Energy Technology Data Exchange (ETDEWEB)

    Cournet, Amandine [Universite de Toulouse, UPS, LU49, Adhesion Bacterienne et Formation de Biofilms, 35 chemin des Maraichers, 31 062 Toulouse cedex 09 (France); Laboratoire de Genie Chimique CNRS, Universite de Toulouse, 4 allee Emile Monso, BP 84234, 31432 Toulouse cedex 04 (France); Delia, Marie-Line; Bergel, Alain [Laboratoire de Genie Chimique CNRS, Universite de Toulouse, 4 allee Emile Monso, BP 84234, 31432 Toulouse cedex 04 (France); Roques, Christine; Berge, Mathieu [Universite de Toulouse, UPS, LU49, Adhesion Bacterienne et Formation de Biofilms, 35 chemin des Maraichers, 31 062 Toulouse cedex 09 (France)

    2010-04-15

    Most bacteria known to be electrochemically active have been harvested in the anodic compartments of microbial fuel cells (MFCs) and are able to use electrodes as electron acceptors. The reverse phenomenon, i.e. using solid electrodes as electron donors, is not so widely studied. To our knowledge, most of the electrochemically active bacteria are Gram-negative. The present study implements a transitory electrochemical technique (cyclic voltammetry) to study the microbial catalysis of the electrochemical reduction of oxygen. It is demonstrated that a wide range of aerobic and facultative anaerobic bacteria are able to catalyze oxygen reduction. Among these electroactive bacteria, several were Gram-positive. The transfer of electrons was direct since no activity was obtained with the filtrate. These findings, showing a widespread property among bacteria including Gram-positive ones, open new and interesting routes in the field of electroactive bacteria research. (author)

  15. Recovery of vancomycin-resistant gram-positive cocci from children.

    OpenAIRE

    Green, M; Wadowsky, R M; Barbadora, K

    1990-01-01

    A cross-sectional survey of vancomycin-resistant gram-positive cocci (VRGPC) in the feces of children was initiated after several bacteremic infections with these organisms occurred at our hospital. A selective medium consisting of colistin-nalidixic acid agar, 5% sheep blood, vancomycin (5 mg/liter), and amphotericin B (8 mg/liter) was developed to isolate VRGPC. A single stool specimen submitted to the clinical microbiology laboratory from each of 48 patients was inoculated onto the medium....

  16. Metabolic versatility of Gram-positive microbial isolates from contaminated river sediments

    International Nuclear Information System (INIS)

    Narancic, Tanja; Djokic, Lidija; Kenny, Shane T.; O’Connor, Kevin E.; Radulovic, Vanja; Nikodinovic-Runic, Jasmina; Vasiljevic, Branka

    2012-01-01

    Highlights: ► Thirty-four isolated Gram-positive bacteria could degrade wide range of aromatic pollutants. ► Nine isolates could grow in the presence of extremely high levels of heavy metals. ► Twelve isolates accumulated polyphosphate, 3 polyhydroxybutyrate, 4 exopolysaccharides. ► The incidence of multiple antibiotic resistance markers among isolates was low. - Abstract: Gram-positive bacteria from river sediments affected by the proximity of a petrochemical industrial site were isolated and characterized with respect to their ability to degrade a wide range of aromatic compounds. In this study we identified metabolically diverse Gram-positive bacteria capable of growth on wide range aromatic compounds in the presence of heavy metals and with the ability to accumulate biopolymers. Thirty-four isolates that were able to use 9 or more common aromatic pollutants, such as benzene, biphenyl, naphthalene etc. as a sole source of carbon and energy included members of Bacillus, Arthrobacter, Rhodococcus, Gordonia, Streptomyces, and Staphylococcus genus. Rhodococcus sp. TN105, Gordonia sp. TN103 and Arthrobacter sp. TN221 were identified as novel strains. Nine isolates were able to grow in the presence of one or more metals (mercury, cadmium, nickel) at high concentration (100 mM). Seven isolates could degrade 15 different aromatic compounds and could grow in the presence of one or more heavy metals. Two of these isolates were resistant to multiple antibiotics including erythromycin and nalidixic acid. One third of isolates could accumulate at least one biopolymer. Twelve isolates (mainly Bacillus sp. and Arthrobacter sp.) accumulated polyphosphate, 3 Bacillus sp. accumulated polyhydroxybutyrate, while 4 isolates could accumulate exopolysaccharides.

  17. Peptidoglycan architecture of Gram-positive bacteria by solid-state NMR.

    Science.gov (United States)

    Kim, Sung Joon; Chang, James; Singh, Manmilan

    2015-01-01

    Peptidoglycan is an essential component of cell wall in Gram-positive bacteria with unknown architecture. In this review, we summarize solid-state NMR approaches to address some of the unknowns in the Gram-positive bacteria peptidoglycan architecture: 1) peptidoglycan backbone conformation, 2) PG-lattice structure, 3) variations in the peptidoglycan architecture and composition, 4) the effects of peptidoglycan bridge-length on the peptidoglycan architecture in Fem mutants, 5) the orientation of glycan strands with respect to the membrane, and 6) the relationship between the peptidoglycan structure and the glycopeptide antibiotic mode of action. Solid-state NMR analyses of Staphylococcus aureus cell wall show that peptidoglycan chains are surprisingly ordered and densely packed. The peptidoglycan disaccharide backbone adopts 4-fold screw helical symmetry with the disaccharide unit periodicity of 40Å. Peptidoglycan lattice in the S. aureus cell wall is formed by cross-linked PG stems that have parallel orientations. The structural characterization of Fem-mutants of S. aureus with varying lengths of bridge structures suggests that the PG-bridge length is an important determining factor for the PG architecture. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Isolation and characterization of Caldicellulosiruptor lactoaceticus sp. nov., an extremely thermophilic, cellulolytic, anaerobic bacterium

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana; Mathrani, Indra M.; Ahring, Birgitte Kiær

    1995-01-01

    An anaerobic, extremely thermophilic, cellulolytic, non-spore-forming bacterium, strain 6A, was isolated from an alkaline hot spring in Hverageroi, Iceland. The bacterium was non-motile, rod-shaped (1.5-3.5 x 0.7 mu m) and occurred singly, in pairs or in chains and stained gram-negative. The growth...

  19. Transposon-mediated random gene disruption with moderate halophilic bacteria and its application for halophilic bacterial siderophore analysis.

    Science.gov (United States)

    Matsui, Toru; Nishino, Tomohiko

    2016-12-01

    Analytical conditions using chromo azurol S was validated for quantification of siderophore in aqueous samples, followed by the characterization of siderophore derived from newly isolated moderately halophilic bacteria. Conditions with good linearity between the absorbance and the siderophore concentration were obtained at a siderophore concentration less than 20 µM, in the wavelength range between 630 and 660 nm with developing time for at least 2 h. Of the halophilic bacteria isolated from Tunisian soil, Halomonas sp., namely strain 21a was selected as siderophore producing halophiles. The strain produced siderophore significantly in the absence of iron in minimal medium. Siderophore-deficient mutant, namely IIa10, of the strain 21a was obtained from gene disruptant library constructed using transposon complex by electroporation. Genomic sequence analysis of the mutant IIa10 revealed that the transposon-inserted gene was TonB-dependent receptor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Silver-doped manganese dioxide and trioxide nanoparticles inhibit both gram positive and gram negative pathogenic bacteria.

    Science.gov (United States)

    Kunkalekar, R K; Prabhu, M S; Naik, M M; Salker, A V

    2014-01-01

    Palladium, ruthenium and silver-doped MnO2 and silver doped Mn2O3 nanoparticles were synthesized by simple co-precipitation technique. SEM-TEM analysis revealed the nano-size of these synthesized samples. XPS data illustrates that Mn is present in 4+ and 3+ oxidation states in MnO2 and Mn2O3 respectively. Thermal analysis gave significant evidence for the phase changes with increasing temperature. Antibacterial activity of these synthesized nanoparticles on three Gram positive bacterial cultures (Staphylococcus aureus ATCC 6538, Streptococcus epidermis ATCC 12228, Bacillus subtilis ATCC 6633) and three Gram negative cultures (Escherichia coli ATCC 8739, Salmonella abony NCTC 6017 and Klebsiella pneumoniae ATCC 1003) was investigated using a disc diffusion method and live/dead assay. Only Ag-doped MnO2 and Ag-doped Mn2O3 nanoparticles showed antibacterial property against all six-test bacteria but Ag-doped MnO2 was found to be more effective than Ag-doped Mn2O3. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

    Science.gov (United States)

    Lu, Hoang D.; Yang, Shirley S.; Wilson, Brian K.; McManus, Simon A.; Chen, Christopher V. H.-H.; Prud'homme, Robert K.

    2017-04-01

    Antimicrobial resistance is a healthcare problem of increasing significance, and there is increasing interest in developing new tools to address bacterial infections. Bacteria-targeting nanoparticles hold promise to improve drug efficacy, compliance, and safety. In addition, nanoparticles can also be used for novel applications, such as bacterial imaging or bioseperations. We here present the use of a scalable block-copolymer-directed self-assembly process, Flash NanoPrecipitation, to form zinc(II)-bis(dipicolylamine) modified nanoparticles that bind to both Gram-positive and Gram-negative bacteria with specificity. Particles have tunable surface ligand densities that change particle avidity and binding efficacy. A variety of materials can be encapsulated into the core of the particles, such as optical dyes or iron oxide colloids, to produce imageable and magnetically active bacterial targeting constructs. As a proof-of-concept, these particles are used to bind and separate bacteria from solution in a magnetic column. Magnetic manipulation and separation would translate to a platform for pathogen identification or removal. These magnetic and targeted nanoparticles enable new methods to address bacterial infections.

  2. Nesterenkonia pannonica sp. nov., a novel alkaliphilic and moderately halophilic actinobacterium.

    Science.gov (United States)

    Borsodi, Andrea K; Szili-Kovács, Tibor; Schumann, Peter; Spröer, Cathrin; Márialigeti, Károly; Tóth, Erika

    2017-10-01

    An alkaliphilic and moderately halophilic bacterial strain characterized by optimal growth at pH 9.0-10.0 and with 5-7 % (w/v) NaCl, designated BV-35 T , was isolated from water of a soda pan located in Kiskunság National Park, Hungary. Cells of the orange-pigmented colony were Gram-stain-positive, non-motile and non-endospore-forming coccoid rods. The isolate was strictly aerobic, catalase-positive and oxidase-negative. Strain BV-35 T displayed a peptidoglycan similar to type A4α, l-Lys-l-Glu (A11.54 according to www.peptidoglycan-types.info) but containing additionally 4-aminobutyric acid. Menaquinone-7 (MK-7) was the predominant isoprenoid quinone, and anteiso-C15 : 0 and anteiso-C17 : 0 were its major cellular fatty acids. The DNA G+C content of strain BV-35 T was 65.4 mol%. Based on 16S rRNA gene sequence similarities, the novel isolate showed the closest relationship to Nesterenkonia populi GP 10-3 T (97.9 %). The DNA-DNA relatedness between BV-35 T and N. populi was 46.7 %. The distinguishing phenotypic and genetic results of this polyphasic study revealed that strain BV-35 T represents a novel member of the genus Nesterenkonia, for which the name Nesterenkonia pannonica sp. nov. is proposed. The type strain is BV-35 T (=DSM 29786 T =NCAIM B 02606 T ).

  3. Complete genome sequence of Vibrio anguillarum strain NB10, a virulent isolate from the Gulf of Bothnia.

    Science.gov (United States)

    Holm, Kåre Olav; Nilsson, Kristina; Hjerde, Erik; Willassen, Nils-Peder; Milton, Debra L

    2015-01-01

    Vibrio anguillarum causes a fatal hemorrhagic septicemia in marine fish that leads to great economical losses in aquaculture world-wide. Vibrio anguillarum strain NB10 serotype O1 is a Gram-negative, motile, curved rod-shaped bacterium, isolated from a diseased fish on the Swedish coast of the Gulf of Bothnia, and is slightly halophilic. Strain NB10 is a virulent isolate that readily colonizes fish skin and intestinal tissues. Here, the features of this bacterium are described and the annotation and analysis of its complete genome sequence is presented. The genome is 4,373,835 bp in size, consists of two circular chromosomes and one plasmid, and contains 3,783 protein-coding genes and 129 RNA genes.

  4. Osmoadaptative Strategy and Its Molecular Signature in Obligately Halophilic Heterotrophic Protists.

    Science.gov (United States)

    Harding, Tommy; Brown, Matthew W; Simpson, Alastair G B; Roger, Andrew J

    2016-08-03

    Halophilic microbes living in hypersaline environments must counteract the detrimental effects of low water activity and salt interference. Some halophilic prokaryotes equilibrate their intracellular osmotic strength with the extracellular milieu by importing inorganic solutes, mainly potassium. These "salt-in" organisms characteristically have proteins that are highly enriched with acidic and hydrophilic residues. In contrast, "salt-out" halophiles accumulate large amounts of organic solutes like amino acids, sugars and polyols, and lack a strong signature of halophilicity in the amino acid composition of cytoplasmic proteins. Studies to date have examined halophilic prokaryotes, yeasts, or algae, thus virtually nothing is known about the molecular adaptations of the other eukaryotic microbes, that is, heterotrophic protists (protozoa), that also thrive in hypersaline habitats. We conducted transcriptomic investigations to unravel the molecular adaptations of two obligately halophilic protists, Halocafeteria seosinensis and Pharyngomonas kirbyi Their predicted cytoplasmic proteomes showed increased hydrophilicity compared with marine protists. Furthermore, analysis of reconstructed ancestral sequences suggested that, relative to mesophiles, proteins in halophilic protists have undergone fewer substitutions from hydrophilic to hydrophobic residues since divergence from their closest relatives. These results suggest that these halophilic protists have a higher intracellular salt content than marine protists. However, absence of the acidic signature of salt-in microbes suggests that Haloc. seosinensis and P. kirbyi utilize organic osmolytes to maintain osmotic equilibrium. We detected increased expression of enzymes involved in synthesis and transport of organic osmolytes, namely hydroxyectoine and myo-inositol, at maximal salt concentration for growth in Haloc. seosinensis, suggesting possible candidates for these inferred organic osmolytes. © The Author 2016

  5. Structural basis for the aminoacid composition of proteins from halophilic archea.

    Directory of Open Access Journals (Sweden)

    Xavier Tadeo

    2009-12-01

    Full Text Available Proteins from halophilic organisms, which live in extreme saline conditions, have evolved to remain folded at very high ionic strengths. The surfaces of halophilic proteins show a biased amino acid composition with a high prevalence of aspartic and glutamic acids, a low frequency of lysine, and a high occurrence of amino acids with a low hydrophobic character. Using extensive mutational studies on the protein surfaces, we show that it is possible to decrease the salt dependence of a typical halophilic protein to the level of a mesophilic form and engineer a protein from a mesophilic organism into an obligate halophilic form. NMR studies demonstrate complete preservation of the three-dimensional structure of extreme mutants and confirm that salt dependency is conferred exclusively by surface residues. In spite of the statistically established fact that most halophilic proteins are strongly acidic, analysis of a very large number of mutants showed that the effect of salt on protein stability is largely independent of the total protein charge. Conversely, we quantitatively demonstrate that halophilicity is directly related to a decrease in the accessible surface area.

  6. Halophilic microorganisms in deteriorated historic buildings: insights into their characteristics.

    Science.gov (United States)

    Adamiak, Justyna; Otlewska, Anna; Gutarowska, Beata; Pietrzak, Anna

    2016-01-01

    Historic buildings are constantly being exposed to numerous climatic changes such as damp and rainwater. Water migration into and out of the material's pores can lead to salt precipitation and the so-called efflorescence. The structure of the material may be seriously threatened by salt crystallization. A huge pressure is produced when salt hydrates occupy larger spaces, which leads at the end to cracking, detachment and material loss. Halophilic microorganisms have the ability to adapt to high salinity because of the mechanisms of inorganic salt (KCl or NaCl) accumulation in their cells at concentrations isotonic to the environment, or compatible solutes uptake or synthesis. In this study, we focused our attention on the determination of optimal growth conditions of halophilic microorganisms isolated from historical buildings in terms of salinity, pH and temperature ranges, as well as biochemical properties and antagonistic abilities. Halophilic microorganisms studied in this paper could be categorized as a halotolerant group, as they grow in the absence of NaCl, as well as tolerate higher salt concentrations (Staphylococcus succinus, Virgibacillus halodenitrificans). Halophilic microorganisms have been also observed (Halobacillus styriensis, H. hunanensis, H. naozhouensis, H. litoralis, Marinococcus halophilus and yeast Sterigmatomyces halophilus). With respect to their physiological characteristics, cultivation at a temperature of 25-30°C, pH 6-7, NaCl concentration for halotolerant and halophilic microorganisms, 0-10% and 15-30%, respectively, provides the most convenient conditions. Halophiles described in this study displayed lipolytic, glycolytic and proteolytic activities. Staphylococcus succinus and Marinococcus halophilus showed strong antagonistic potential towards bacteria from the Bacillus genus, while Halobacillus litoralis displayed an inhibiting ability against other halophiles.

  7. Identification of aerobic Gram-positive bacilli by use of Vitek MS.

    Science.gov (United States)

    Navas, Maria; Pincus, David H; Wilkey, Kathy; Sercia, Linda; LaSalvia, Margaret; Wilson, Deborah; Procop, Gary W; Richter, Sandra S

    2014-04-01

    The accuracy of Vitek MS mass spectrometric identifications was assessed for 206 clinically significant isolates of aerobic Gram-positive bacilli representing 20 genera and 38 species. The Vitek MS identifications were correct for 85% of the isolates (56.3% to the species level, 28.6% limited to the genus level), with misidentifications occurring for 7.3% of the isolates.

  8. Borrelidins C-E: New Antibacterial Macrolides from a Saltern-Derived Halophilic Nocardiopsis sp.

    Science.gov (United States)

    Kim, Jungwoo; Shin, Daniel; Kim, Seong-Hwan; Park, Wanki; Shin, Yoonho; Kim, Won Kyung; Lee, Sang Kook; Oh, Ki-Bong; Shin, Jongheon; Oh, Dong-Chan

    2017-06-06

    Chemical investigation of a halophilic actinomycete strain belonging to the genus Nocardiopsis inhabiting a hypersaline saltern led to the discovery of new 18-membered macrolides with nitrile functionality, borrelidins C-E ( 1 - 3 ), along with a previously reported borrelidin ( 4 ). The planar structures of borrelidins C-E, which are new members of the rare borrelidin class of antibiotics, were elucidated by NMR, mass, IR, and UV spectroscopic analyses. The configurations of borrelidines C-E were determined by the interpretation of ROESY NMR spectra, J-based configuration analysis, a modified Mosher's method, and CD spectroscopic analysis. Borrelidins C and D displayed inhibitory activity, particularly against the Gram-negative pathogen Salmonella enterica , and moderate cytotoxicity against the SNU638 and K562 carcinoma cell lines.

  9. In vitro activities of dalbavancin and nine comparator agents against anaerobic gram-positive species and corynebacteria.

    Science.gov (United States)

    Goldstein, Ellie J C; Citron, Diane M; Merriam, C Vreni; Warren, Yumi; Tyrrell, Kerin; Fernandez, Helen T

    2003-06-01

    Dalbavancin is a novel semisynthetic glycopeptide with enhanced activity against gram-positive species. Its comparative in vitro activities and those of nine comparator agents, including daptomycin, vancomycin, linezolid, and quinupristin-dalfopristin, against 290 recent gram-positive clinical isolates strains, as determined by the NCCLS agar dilution method, were studied. The MICs of dalbavancin at which 90% of various isolates tested were inhibited were as follows: Actinomyces spp., 0.5 microg/ml; Clostridium clostridioforme, 8 microg/ml; C. difficile, 0.25 microg/ml; C. innocuum, 0.25 microg/ml; C. perfringens, 0.125 microg/ml; C. ramosum, 1 microg/ml; Eubacterium spp., 1 microg/ml; Lactobacillus spp., >32 microg/ml, Propionibacterium spp., 0.5 microg/ml; and Peptostreptococcus spp., 0.25 microg/ml. Dalbavancin was 1 to 3 dilutions more active than vancomycin against most strains. Dalbavancin exhibited excellent activity against gram-positive strains tested and warrants clinical evaluation.

  10. Dose-Dependent Antimicrobial Activity of Silver Nanoparticles on Polycaprolactone Fibers against Gram-Positive and Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Erick Pazos-Ortiz

    2017-01-01

    Full Text Available The adhesion ability and adaptability of bacteria, coupled with constant use of the same bactericides, have made the increase in the diversity of treatments against infections necessary. Nanotechnology has played an important role in the search for new ways to prevent and treat infections, including the use of metallic nanoparticles with antibacterial properties. In this study, we worked on the design of a composite of silver nanoparticles (AgNPS embedded in poly-epsilon-caprolactone nanofibers and evaluated its antimicrobial properties against various Gram-positive and Gram-negative microorganisms associated with drug-resistant infections. Polycaprolactone-silver composites (PCL-AgNPs were prepared in two steps. The first step consisted in the reduction in situ of Ag+ ions using N,N-dimethylformamide (DMF in tetrahydrofuran (THF solution, and the second step involved the simple addition of polycaprolactone before electrospinning process. Antibacterial activity of PCL-AgNPs nanofibers against E. coli, S. mutans, K. pneumoniae, S. aureus, P. aeruginosa, and B. subtilis was evaluated. Results showed sensibility of E. coli, K. pneumoniae, S. aureus, and P. aeruginosa, but not for B. subtilis and S. mutans. This antimicrobial activity of PCL-AgNPs showed significant positive correlations associated with the dose-dependent effect. The antibacterial property of the PCL/Ag nanofibers might have high potential medical applications in drug-resistant infections.

  11. Halomonas sp. BS4, A biosurfactant producing halophilic bacterium isolated from solar salt works in India and their biomedical importance

    OpenAIRE

    Donio, Mariathason Birdilla Selva; Ronica, Fernando Arul; Viji, Vijayaragavan Thanga; Velmurugan, Subramanian; Jenifer, John Selesteen Charles Adlin; Michaelbabu, Mariavincent; Dhar, Prasenjit; Citarasu, Thavasimuthu

    2013-01-01

    Halophilic bacteria were isolated from Thamaraikulam solar salt works in India. After routine biosurfactant screening by various methods, the biosurfactant producing bacteria, Halomonas sp BS4 was confirmed by 16?S rRNA sequencing. The growth optimization of Halomonas sp BS4 revealed their optimum growth at 8% NaCl and 6-8?pH in the growth medium. Further the partially purified biosurfactants were characterized by TLC, FTIR and GC-MS analysis. GC-MS results revealed that, the partial purified...

  12. Halophilic Amylase from a Moderately Halophilic Micrococcus

    Science.gov (United States)

    Onishi, Hiroshi

    1972-01-01

    A moderately halophilic Micrococcus sp., isolated from unrefined solar salt, produced a considerable amount of extracellular dextrinogenic amylase when cultivated aerobically in media containing 1 to 3 m NaCl. The Micrococcus amylase had maximal activity at pH 6 to 7 in 1.4 to 2 m NaCl or KCl at 50 C. Calcium ion and a high concentration of NaCl or KCl were essential for activity and stability of the amylase. The salt response of the amylase depended greatly on the pH and temperature of the enzyme assay. PMID:5058445

  13. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms

    Energy Technology Data Exchange (ETDEWEB)

    Uma Suganya, K.S. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Govindaraju, K., E-mail: govindtu@gmail.com [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Ganesh Kumar, V.; Stalin Dhas, T.; Karthick, V. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Singaravelu, G. [Nanoscience Division, Department of Zoology, Thiruvalluvar University, Vellore 632115 (India); Elanchezhiyan, M. [Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600113 (India)

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet–visible (UV–vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ∼ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. - Highlights: • Size controlled synthesis of gold nanoparticles from blue green alga Spirulina platensis • Stability of gold nanoparticles at different temperatures • Potent antibacterial efficacy against Gram positive organisms.

  14. Inhibition of various gram-positive and gram-negative bacteria growth on selenium nanoparticle coated paper towels.

    Science.gov (United States)

    Wang, Qi; Larese-Casanova, Philip; Webster, Thomas J

    2015-01-01

    There are wide spread bacterial contamination issues on various paper products, such as paper towels hanging in sink splash zones or those used to clean surfaces, filter papers used in water and air purifying systems, and wrappings used in the food industry; such contamination may lead to the potential spread of bacteria and consequent severe health concerns. In this study, selenium nanoparticles were coated on normal paper towel surfaces through a quick precipitation method, introducing antibacterial properties to the paper towels in a healthy way. Their effectiveness at preventing biofilm formation was tested in bacterial assays involving Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus epidermidis. The results showed significant and continuous bacteria inhibition with about a 90% reduction from 24 to 72 hours for gram-positive bacteria including S. aureus and S. epidermidis. The selenium coated paper towels also showed significant inhibition of gram-negative bacteria like P. aeruginosa and E. coli growth at about 57% and 84%, respectively, after 72 hours of treatment. Therefore, this study established a promising selenium-based antibacterial strategy to prevent bacterial growth on paper products, which may lead to the avoidance of bacteria spreading and consequent severe health concerns.

  15. THE HALOPHILICITY OF FILAMENTOUS FUNGI ISOLATED FROM SALINE SOILS OF SOUTH CAUCASUS

    Directory of Open Access Journals (Sweden)

    Kvesitadze E.

    2015-08-01

    Full Text Available The work is devoted to the isolation, purification, determination of taxonomical characteristics and application in soil improvement and other biotechnological processes halophilic microscopic fungi strains isolated from saline soils of Eastern Georgia (middle part of South Caucasus, where their existence is maximally supposed. In all soilclimatic zones the dominate forms of spread fungi are genera Aspergillus, Penicillium and Fusarium, followed by Trichoderma and Mucor. Other genera are met less intensively. The genera Aspergillus is widely spread in chestnut soils and in chernozem, in green forest soils the genera Penicillium is prevailing. The salinity of soil, lake or any other objects from which the isolation of microscopic fungi is performed greatly determines halophilisity of isolated strains. Finally, the collection of halophilic microscopic fungi has been created accounting 96 isolates of extreme halophiles, halophiles and week halophiles.

  16. In vitro activity of tigecycline and comparator agents against a global collection of Gram-negative and Gram-positive organisms: tigecycline Evaluation and Surveillance Trial 2004 to 2007.

    Science.gov (United States)

    Garrison, Mark W; Mutters, Reinier; Dowzicky, Michael J

    2009-11-01

    The Tigecycline Evaluation and Surveillance Trial began in 2004 to monitor the in vitro activity of tigecycline and comparator agents against a global collection of Gram-negative and Gram-positive pathogens. Against Gram negatives (n = 63 699), tigecycline MIC(90)'s ranged from 0.25 to 2 mg/L for Escherichia coli, Haemophilus influenzae, Acinetobacter baumannii, Klebsiella oxytoca, Enterobacter cloacae, Klebsiella pneumoniae, and Serratia marcescens (but was > or =32 for Pseudomonas aeruginosa). Against Gram-positive organisms (n = 32 218), tigecycline MIC(90)'s were between 0.06 and 0.25 mg/L for Streptococcus pneumoniae, Enterococcus faecium, Streptococcus agalactiae, Staphylococcus aureus, and Enterococcus faecalis. The in vitro activity of tigecycline was maintained against resistant phenotypes, including multidrug-resistant A. baumannii (9.2% of isolates), extended-spectrum beta-lactamase-producing E. coli (7.0%) and K. pneumoniae (14.0%), beta-lactamase-producing H. influenzae (22.2%), methicillin-resistant S. aureus (44.5%), vancomycin-resistant E. faecium (45.9%) and E. faecalis (2.8%), and penicillin-resistant S. pneumoniae (13.8%). Tigecycline represents a welcome addition to the armamentarium against difficult to treat organisms.

  17. Gram staining for the treatment of peritonsillar abscess.

    Science.gov (United States)

    Takenaka, Yukinori; Takeda, Kazuya; Yoshii, Tadashi; Hashimoto, Michiko; Inohara, Hidenori

    2012-01-01

    Objective. To examine whether Gram staining can influence the choice of antibiotic for the treatment of peritonsillar abscess. Methods. Between 2005 and 2009, a total of 57 cases of peritonsillar abscess were analyzed with regard to cultured bacteria and Gram staining. Results. Only aerobes were cultured in 16% of cases, and only anaerobes were cultured in 51% of cases. Mixed growth of aerobes and anaerobes was observed in 21% of cases. The cultured bacteria were mainly aerobic Streptococcus, anaerobic Gram-positive cocci, and anaerobic Gram-negative rods. Phagocytosis of bacteria on Gram staining was observed in 9 cases. The bacteria cultured from these cases were aerobic Streptococcus, anaerobic Gram-positive cocci, and anaerobic Gram-negative rods. The sensitivity of Gram staining for the Gram-positive cocci and Gram-negative rods was 90% and 64%, respectively. The specificity of Gram staining for the Gram-positive cocci and Gram-negative rods was 62% and 76%, respectively. Most of the Gram-positive cocci were sensitive to penicillin, but some of anaerobic Gram-negative rods were resistant to penicillin. Conclusion. When Gram staining shows only Gram-positive cocci, penicillin is the treatment of choice. In other cases, antibiotics effective for the penicillin-resistant organisms should be used.

  18. Disruption and analysis of the clpB, clpC, and clpE genes in Lactococcus lactis: ClpE, a new Clp family in gram-positive bacteria

    DEFF Research Database (Denmark)

    Ingmer, Hanne; Vogensen, Finn K.; Hammer, Karin

    1999-01-01

    In the genome of the gram-positive bacterium Lactococcus lactis MG1363, we have identified three genes (clpC, clpE, and clpB) which encode Clp proteins containing two conserved ATP binding domains. The proteins encoded by two of the genes belong to the previously described ClpB and ClpC families....... The clpE gene, however, encodes a member of a new Clp protein family that is characterized by a short N-terminal domain including a putative zinc binding domain (-CX2CX22CX2C-). Expression of the 83-kDa ClpE protein as well as of the two proteins encoded by clpB was strongly induced by heat shock and...... was shown to participate in the degradation of randomly folded proteins in L. lactis, could be necessary for degrading proteins generated by certain types of stress....

  19. Recovery of metallo-tolerant and antibiotic resistant psychrophilic bacteria from Siachen glacier, Pakistan.

    Directory of Open Access Journals (Sweden)

    Muhammad Rafiq

    Full Text Available Cultureable bacterial diversity of previously unexplored Siachen glacier, Pakistan, was studied. Out of 50 isolates 33 (66% were Gram negative and 17 (34% Gram positive. About half of the isolates were pigment producers and were able to grow at 4-37°C. 16S rRNA gene sequences revealed Gram negative bacteria dominated by Proteobacteria (especially γ-proteobacteria and β-proteobacteria and Flavobacteria. The genus Pseudomonas (51.51%, 17 was dominant among γ- proteobacteria. β-proteobacteria constituted 4 (12.12% Alcaligenes and 4 (12.12% Janthinobacterium strains. Among Gram positive bacteria, phylum Actinobacteria, Rhodococcus (23.52%, 4 and Arthrobacter (23.52%, 4 were the dominating genra. Other bacteria belonged to Phylum Firmicutes with representative genus Carnobacterium (11.76%, 2 and 4 isolates represented 4 genera Bacillus, Lysinibacillus, Staphylococcus and Planomicrobium. Most of the Gram negative bacteria were moderate halophiles, while most of the Gram positives were extreme halophiles and were able to grow up to 6.12 M of NaCl. More than 2/3 of the isolates showed antimicrobial activity against multidrug resistant S. aureus, E. coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans, Aspergillus flavus and Aspergillus fumigatus and ATCC strains. Gram positive bacteria (94.11% were more resistant to heavy metals as compared to Gram negative (78.79% and showed maximum tolerance against iron and least tolerance against mercury.

  20. Transformation and Stability of Cloned Polysaccharidase Genes in Gram-Positive Bacteria

    OpenAIRE

    EKİNCİ, Mehmet Sait

    2014-01-01

    Polysaccharidase genes from rumen bacteria were transferred to and expressed in ruminal and non-ruminal Gram-positive bacteria. The transformation efficiency and genetic stability of polysaccharidase genes in bacteria from different habitats were investigated. PCR amplification of cloned polysaccharidase genes from Escherichia coli, Lactococcus lactis, Enterococcus faecalis, Streptococcus sanguis and S. bovis strain 26 showed that rearrangement of plasmid and the gene fragment did not occur. ...

  1. Rational approaches to the therapy of nosocomial infections caused by gram-positive microorganisms in cancer p

    Directory of Open Access Journals (Sweden)

    V. V. Aginova

    2017-01-01

    Full Text Available Nosocomial infections caused by gram-positive organisms, including Staphylococcus aureus and enterococci (Enterococcus faecium and Enterococcus faecalis are steadily increasing in almost all clinics around the world. Cancer patients have a higher risk of hospital-acquired infections than non-cancer patients. Cancer patients are immunosuppressed due to increased use of broad-spectrum antibiotics and chemotherapy drugs, radiation therapy, surgery and use of steroids. This paper presents an analysis of resistance of gram-positive bacterial pathogens to antimicrobial agents to determine treatment strategy for cancer patients.

  2. Differential staining of bacteria: gram stain.

    Science.gov (United States)

    Moyes, Rita B; Reynolds, Jackie; Breakwell, Donald P

    2009-11-01

    In 1884, Hans Christian Gram, a Danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division. This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure: Gram-positive cocci, Gram-negative cocci, Gram-positive rods, and Gram-negative rods. The Gram stain is useful for assessing bacterial contamination of tissue culture samples or for examining the Gram stain status and morphological features of bacteria isolated from mixed or isolated bacterial cultures. (c) 2009 by John Wiley & Sons, Inc.

  3. Culturable diversity of halophilic bacteria in foreshore soils.

    Science.gov (United States)

    Irshad, Aarzoo; Ahmad, Irshad; Kim, Seung Bum

    2014-01-01

    Halophilic bacteria are commonly found in natural environments containing significant concentration of NaCl such as inland salt lakes and evaporated sea-shore pools, as well as environments such as curing brines, salted food products and saline soils. Dependence on salt is an important phenotypic characteristic of halophilic bacteria, which can be used in the polyphasic characterization of newly discovered microorganisms. In this study the diversity of halophilic bacteria in foreshore soils of Daecheon, Chungnam, and Saemangeum, Jeonbuk, was investigated. Two types of media, namely NA and R2A supplemented with 3%, 5%, 9%, 15%, 20% and 30% NaCl were used. More than 200 halophilic bacteria were isolated and BOX-PCR fingerprinting analysis was done for the typing of the isolates. The BLAST identification results showed that isolated strains were composed of 4 phyla, Firmicutes (60%), Proteobacteria (31%), Bacteriodetes (5%) and Actinobacteria (4%). Isolates were affiliated with 16 genera and 36 species. Bacillus was the dominant genus in the phylum Firmicutes, comprising 24% of the total isolates. Halomonas (12%) and Shewanella (12%) were also found as the main genera. These findings show that the foreshore soil of Daecheon Beach and Saemangeum Sea of Korea represents an untapped source of bacterial biodiversity.

  4. Culturable diversity of halophilic bacteria in foreshore soils

    Directory of Open Access Journals (Sweden)

    Aarzoo Irshad

    2014-06-01

    Full Text Available Halophilic bacteria are commonly found in natural environments containing significant concentration of NaCl such as inland salt lakes and evaporated sea-shore pools, as well as environments such as curing brines, salted food products and saline soils. Dependence on salt is an important phenotypic characteristic of halophilic bacteria, which can be used in the polyphasic characterization of newly discovered microorganisms. In this study the diversity of halophilic bacteria in foreshore soils of Daecheon, Chungnam, and Saemangeum, Jeonbuk, was investigated. Two types of media, namely NA and R2A supplemented with 3%, 5%, 9%, 15%, 20% and 30% NaCl were used. More than 200 halophilic bacteria were isolated and BOX-PCR fingerprinting analysis was done for the typing of the isolates. The BLAST identification results showed that isolated strains were composed of 4 phyla, Firmicutes (60%, Proteobacteria (31%, Bacteriodetes (5% and Actinobacteria (4%. Isolates were affiliated with 16 genera and 36 species. Bacillus was the dominant genus in the phylum Firmicutes, comprising 24% of the total isolates. Halomonas (12% and Shewanella (12% were also found as the main genera. These findings show that the foreshore soil of Daecheon Beach and Saemangeum Sea of Korea represents an untapped source of bacterial biodiversity.

  5. Antibacterial activity of sphingoid bases and fatty acids against Gram-positive and Gram-negative bacteria.

    Science.gov (United States)

    Fischer, Carol L; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

    2012-03-01

    There is growing evidence that the role of lipids in innate immunity is more important than previously realized. How lipids interact with bacteria to achieve a level of protection, however, is still poorly understood. To begin to address the mechanisms of antibacterial activity, we determined MICs and minimum bactericidal concentrations (MBCs) of lipids common to the skin and oral cavity--the sphingoid bases D-sphingosine, phytosphingosine, and dihydrosphingosine and the fatty acids sapienic acid and lauric acid--against four Gram-negative bacteria and seven Gram-positive bacteria. Exact Kruskal-Wallis tests of these values showed differences among lipid treatments (P 500 μg/ml). Sapienic acid (MBC range, 31.3 to 375.0 μg/ml) was active against Streptococcus sanguinis, Streptococcus mitis, and Fusobacterium nucleatum but not active against Escherichia coli, Staphylococcus aureus, S. marcescens, P. aeruginosa, Corynebacterium bovis, Corynebacterium striatum, and Corynebacterium jeikeium (MBC > 500 μg/ml). Lauric acid (MBC range, 6.8 to 375.0 μg/ml) was active against all bacteria except E. coli, S. marcescens, and P. aeruginosa (MBC > 500 μg/ml). Complete killing was achieved as early as 0.5 h for some lipids but took as long as 24 h for others. Hence, sphingoid bases and fatty acids have different antibacterial activities and may have potential for prophylactic or therapeutic intervention in infection.

  6. A synbio approach for selection of highly expressed gene variants in Gram-positive bacteria.

    Science.gov (United States)

    Ferro, Roberto; Rennig, Maja; Hernández-Rollán, Cristina; Daley, Daniel O; Nørholm, Morten H H

    2018-03-08

    The market for recombinant proteins is on the rise, and Gram-positive strains are widely exploited for this purpose. Bacillus subtilis is a profitable host for protein production thanks to its ability to secrete large amounts of proteins, and Lactococcus lactis is an attractive production organism with a long history in food fermentation. We have developed a synbio approach for increasing gene expression in two Gram-positive bacteria. First of all, the gene of interest was coupled to an antibiotic resistance gene to create a growth-based selection system. We then randomised the translation initiation region (TIR) preceding the gene of interest and selected clones that produced high protein titres, as judged by their ability to survive on high concentrations of antibiotic. Using this approach, we were able to significantly increase production of two industrially relevant proteins; sialidase in B. subtilis and tyrosine ammonia lyase in L. lactis. Gram-positive bacteria are widely used to produce industrial enzymes. High titres are necessary to make the production economically feasible. The synbio approach presented here is a simple and inexpensive way to increase protein titres, which can be carried out in any laboratory within a few days. It could also be implemented as a tool for applications beyond TIR libraries, such as screening of synthetic, homologous or domain-shuffled genes.

  7. Peptidoglycan Recycling in Gram-Positive Bacteria Is Crucial for Survival in Stationary Phase

    Science.gov (United States)

    Borisova, Marina; Gaupp, Rosmarie; Duckworth, Amanda; Schneider, Alexander; Dalügge, Désirée; Mühleck, Maraike; Deubel, Denise; Unsleber, Sandra; Yu, Wenqi; Muth, Günther; Bischoff, Markus; Götz, Friedrich

    2016-01-01

    ABSTRACT Peptidoglycan recycling is a metabolic process by which Gram-negative bacteria reutilize up to half of their cell wall within one generation during vegetative growth. Whether peptidoglycan recycling also occurs in Gram-positive bacteria has so far remained unclear. We show here that three Gram-positive model organisms, Staphylococcus aureus, Bacillus subtilis, and Streptomyces coelicolor, all recycle the sugar N-acetylmuramic acid (MurNAc) of their peptidoglycan during growth in rich medium. They possess MurNAc-6-phosphate (MurNAc-6P) etherase (MurQ in E. coli) enzymes, which are responsible for the intracellular conversion of MurNAc-6P to N-acetylglucosamine-6-phosphate and d-lactate. By applying mass spectrometry, we observed accumulation of MurNAc-6P in MurNAc-6P etherase deletion mutants but not in either the isogenic parental strains or complemented strains, suggesting that MurQ orthologs are required for the recycling of cell wall-derived MurNAc in these bacteria. Quantification of MurNAc-6P in ΔmurQ cells of S. aureus and B. subtilis revealed small amounts during exponential growth phase (0.19 nmol and 0.03 nmol, respectively, per ml of cells at an optical density at 600 nm [OD600] of 1) but large amounts during transition (0.56 nmol and 0.52 nmol) and stationary (0.53 nmol and 1.36 nmol) phases. The addition of MurNAc to ΔmurQ cultures greatly increased the levels of intracellular MurNAc-6P in all growth phases. The ΔmurQ mutants of S. aureus and B. subtilis showed no growth deficiency in rich medium compared to the growth of the respective parental strains, but intriguingly, they had a severe survival disadvantage in late stationary phase. Thus, although peptidoglycan recycling is apparently not essential for the growth of Gram-positive bacteria, it provides a benefit for long-term survival. PMID:27729505

  8. Copper-resistant halophilic bacterium isolated from the polluted Maruit Lake, Egypt.

    Science.gov (United States)

    Osman, O; Tanguichi, H; Ikeda, K; Park, P; Tanabe-Hosoi, S; Nagata, S

    2010-04-01

    To isolate and characterize copper-resistant halophilic bacteria from the polluted Maruit Lake, Egypt and identify the role of plasmids in toxic metal resistance. We isolated strain MA2, showing high copper resistance up to the 1.5 mmol l(-1) concentration; it was also resistant to other metals such as nickel, cobalt and zinc and a group of antibiotics. Partial 16S rRNA analysis revealed that strain MA2 belonged to the genus Halomonas. Copper uptake, measured by atomic absorption spectrophotometery, was higher in the absence of NaCl than in the presence of 0.5-1.0 mol l(-1) NaCl during 5-15 min of incubation. Cell fractionation and electron microscopic observation clarified that most of the copper accumulated in the outer membrane and periplasmic fractions of the cells. Plasmid screening yielded two plasmids: pMA21 (11 kb) and pMA22 (5 kb). Plasmid curing resulted in a strain that lost both the plasmids and was sensitive to cobalt and chromate but not copper, nickel and zinc. This cured strain also showed weak growth in the presence of 0.5-1.0 mol l(-1) NaCl. Partial sequencing of both plasmids led to the identification of different toxic metals transporters but copper transporters were not identified. The highest cell viability was found in the presence of 1.0 mol l(-1) NaCl at different copper concentrations, and copper uptake was optimal in the absence of NaCl. Plasmid pMA21 encoded chromate, cobalt, zinc and cadmium transporters, whereas pMA22 encoded specific zinc and RND (resistance, nodulation, cell division) efflux transporters as well as different kinds of metabolic enzymes. Copper resistance was mainly incorporated in the chromosome. Strain MA2 is a fast and efficient tool for copper bioremediation and the isolated plasmids show significant characteristics of both toxic metal and antibiotic resistance.

  9. Flavins mediate extracellular electron transfer in Gram-positive Bacillus megaterium strain LLD-1

    DEFF Research Database (Denmark)

    You, Le-Xing; Liu, Li-Dan; Xiao, Yong

    2018-01-01

    The extracellular electron transfer (EET) mechanism of an isolated Gram-positive Bacillus megaterium strain (LLD-1), identified by 16S rRNA gene sequencing and physiological analysis, was investigated in the present study. The electrochemical activity of strain LLD-1 was confirmed by electrochemi...

  10. Methylophaga natronica sp. nov., a new alkaliphilic and moderately halophilic, restricted-facultatively methylotrophic bacterium from soda lake of the Southern Transbaikal region.

    Science.gov (United States)

    Doronina, Nina; Darmaeva, Tsyregma; Trotsenko, Yuri

    2003-09-01

    A new, moderately haloalkaliphilic and restricted-facultatively methylotrophic bacterium (strain Bur2T) with the ribulose monophosphate pathway of carbon assimilation is described. The isolate, which utilizes methanol, methylamine and fructose, is an aerobic, Gram-negative, asporogenous, motile short rod multiplying by binary fission. It is auxotrophic for vitamin B12, and requires NaHCO3 or NaCl for growth in alkaline medium. Cellular fatty acids profile consists primarily of straight-chain saturated C16:0, unsaturated C16:1 and C18:1 acids. The major ubiquinone is Q-8. The dominant phospholipids are phosphatidylethanolamine and phosphatidylglycerol. Diphosphatidylglycerol is also present. Optimal growth conditions are 25-29 degrees C, pH 8.5-9.0 and 2-3% (w/v) NaCl. Cells accumulate ectoine and glutamate as the main osmoprotectants. The G + C content of the DNA is 45.0 mol%. Based on 16S rDNA sequence analysis and DNA-DNA relatedness (25-35%) with type strains of marine and soda lake methylobacteria belonging to the genus Methylophaga, the novel isolate was classified as a new species of this genus and named Methylophaga natronica (VKM B-2288T).

  11. Complete genome sequence of Spirochaeta smaragdinae type strain (SEBR 4228T)

    Energy Technology Data Exchange (ETDEWEB)

    Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Yasawong, Montri [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Chertkov, Olga [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Bruce, David [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Chang, Yun-Juan [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Sikorski, Johannes [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute

    2010-01-01

    Spirochaeta smaragdinae Magot et al. 1998 belongs to the family Spirochaetaceae. The species is Gram-negative, motile, obligately halophilic and strictly anaerobic bacterium, which is of interest because it is able to ferment numerous polysaccharides. S. smaragdinae is the only species of the family Spirochaetaceae known to reduce thiosulfate or element sulphur to sulfide. This is the first complete genome sequence in the family Spirochaetaceae. The 4,653,970 bp long genome with its 4,363 protein-coding and 57 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  12. Diversity of halophilic archaea in fermented foods and human intestines and their application.

    Science.gov (United States)

    Lee, Han-Seung

    2013-12-01

    Archaea are prokaryotic organisms distinct from bacteria in the structural and molecular biological sense, and these microorganisms are known to thrive mostly at extreme environments. In particular, most studies on halophilic archaea have been focused on environmental and ecological researches. However, new species of halophilic archaea are being isolated and identified from high salt-fermented foods consumed by humans, and it has been found that various types of halophilic archaea exist in food products by culture-independent molecular biological methods. In addition, even if the numbers are not quite high, DNAs of various halophilic archaea are being detected in human intestines and much interest is given to their possible roles. This review aims to summarize the types and characteristics of halophilic archaea reported to be present in foods and human intestines and to discuss their application as well.

  13. The Effect of Charge at the Surface of Silver Nanoparticles on Antimicrobial Activity against Gram-Positive and Gram-Negative Bacteria: A Preliminary Study

    International Nuclear Information System (INIS)

    Abbaszadegan, A.; Ghahramani, Y.; Nabavizadeh, M.; Gholami, A.; Hemmateenejad, I.; Dorostkar, S.; Sharghi, H.

    2014-01-01

    The bactericidal efficiency of various positively and negatively charged silver nanoparticles has been extensively evaluated in literature, but there is no report on efficacy of neutrally charged silver nanoparticles. The goal of this study is to evaluate the role of electrical charge at the surface of silver nanoparticles on antibacterial activity against a panel of microorganisms. Three different silver nanoparticles were synthesized by different methods, providing three different electrical surface charges (positive, neutral, and negative). The antibacterial activity of these nanoparticles was tested against gram-positive (i.e., Staphylococcus aureus, Streptococcus mutans, and Streptococcus pyogenes) and gram-negative (i.e., Escherichia coli and Proteus vulgaris) bacteria. Well diffusion and micro-dilution tests were used to evaluate the bactericidal activity of the nanoparticles. According to the obtained results, the positively-charged silver nanoparticles showed the highest bactericidal activity against all microorganisms tested. The negatively charged silver nanoparticles had the least and the neutral nanoparticles had intermediate antibacterial activity. The most resistant bacteria were Proteus vulgaris. We found that the surface charge of the silver nanoparticles was a significant factor affecting bactericidal activity on these surfaces. Although the positively charged nanoparticles showed the highest level of effectiveness against the organisms tested, the neutrally charged particles were also potent against most bacterial species.

  14. Biotechnological applications of halophilic lipases and thioesterases.

    Science.gov (United States)

    Schreck, Steven D; Grunden, Amy M

    2014-02-01

    Lipases and esterases are enzymes which hydrolyze ester bonds between a fatty acid moiety and an esterified conjugate, such as a glycerol or phosphate. These enzymes have a wide spectrum of use in industrial applications where their high activity, broad substrate specificity, and stability under harsh conditions have made them integral in biofuel production, textile processing, waste treatment, and as detergent additives. To date, these industrial applications have mainly leveraged enzymes from mesophilic and thermophilic organisms. However, increasingly, attention has turned to halophilic enzymes as catalysts in environments where high salt stability is desired. This review provides a brief overview of lipases and esterases and examines specific structural motifs and evolutionary adaptations of halophilic lipases. Finally, we examine the state of research involving these enzymes and provide an in-depth look at an exciting algal-based biofuel production system. This system uses a recombinant halophilic lipase to increase oil production efficiency by cleaving algal fatty acids from the acyl carrier protein, which eliminates feedback inhibition of fatty acid synthesis.

  15. Gram-positive bacteria as an antigen topically applied into gingival sulcus of immunized rat accelerates periodontal destruction.

    Science.gov (United States)

    Nagano, F; Kaneko, T; Yoshinaga, Y; Ukai, T; Kuramoto, A; Nakatsu, S; Oshino, K; Ichimura, I; Hara, Y

    2013-08-01

    Periodontitis is generally accepted to relate to gram-negative bacteria, and the host defense system influences its onset and progression. However, little is known about the relation between gram-positive bacteria and periodontitis. In this study, we topically applied gram-positive and gram-negative bacterial suspensions to the gingival sulcus in rats after immunization, and then histopathologically examined their influence on periodontal destruction. Rats previously immunized with heat-treated and sonicated Staphylococcus aureus or Aggregatibacter actinomycetemcomitans were used as immunized groups. The non-immunized group received only sterile phosphate-buffered saline. In each animal, S. aureus or A. actinomycetemcomitans suspension was applied topically to the palatal gingival sulcus of first molars every 24 h for 10 d. Blood samples were collected and the serum level of anti-S. aureus or anti-A. actinomycetemcomitans immunoglobulin G (IgG) antibodies was determined by enzyme-linked immunosorbent assay. The first molar regions were resected and observed histopathologically. Osteoclasts were stained with tartrate-resistant acid phosphatase (TRAP). The formation of immune complexes was confirmed by immunohistological staining of C1qB. Serum levels of anti-S. aureus and anti-A. actinomycetemcomitans IgG antibodies in the immunized groups were significantly higher than those in the non-immunized groups were. The loss of attachment, increase in apical migration of the junctional epithelium, and decreases in alveolar bone level and number of TRAP-positive multinuclear cells in each immunized group were significantly greater than in each non-immunized group. The presence of C1qB was observed in the junctional epithelium and adjacent connective tissue in the immunized groups. Heat-treated and sonicated S. aureus and A. actinomycetemcomitans induced attachment loss in rats immunized with their suspensions. Our results suggest that not only gram-negative but also gram-positive

  16. Aliidiomarina haloalkalitolerans sp. nov., a marine bacterium isolated from coastal surface seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, T.N.R.; Nupur; AnilKumar, P.

    A novel Gram-negative, rod shaped, motile, non-sporing strictly aerobic bacterium, designated strain AK5 sup(T), was isolated from a sea water sample collected near Visakhapatnam coast, Bay of Bengal, India. Colonies on marine agar were circular, 3...

  17. Endocarditis associated with cardiac catheterization due to a Gram-positive coccus designated Micrococcus mucilaginosus incertae sedis.

    Science.gov (United States)

    Rubin, S J; Lyons, R W; Murcia, A J

    1978-01-01

    A gram-positive coccus, presently named Micrococcus mucilaginosus incertae sedis, was isolated from 14 blood cultures from a patient with endocarditis. The first positive blood culture was drawn 5 days after the patient underwent cardiac catheterization. PMID:670378

  18. A synbio approach for selection of highly expressed gene variants in Gram-positive bacteria

    DEFF Research Database (Denmark)

    Ferro, Roberto; Rennig, Maja; Hernández Rollán, Cristina

    2018-01-01

    with a long history in food fermentation. We have developed a synbio approach for increasing gene expression in two Gram-positive bacteria. First of all, the gene of interest was coupled to an antibiotic resistance gene to create a growth-based selection system. We then randomised the translation initiation...... region (TIR) preceding the gene of interest and selected clones that produced high protein titres, as judged by their ability to survive on high concentrations of antibiotic. Using this approach, we were able to significantly increase production of two industrially relevant proteins; sialidase in B....... subtilis and tyrosine ammonia lyase in L. lactis. Gram-positive bacteria are widely used to produce industrial enzymes. High titres are necessary to make the production economically feasible. The synbio approach presented here is a simple and inexpensive way to increase protein titres, which can be carried...

  19. Stable transformation of the gram-positive phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus with several cloning vectors.

    Science.gov (United States)

    Laine, M J; Nakhei, H; Dreier, J; Lehtilä, K; Meletzus, D; Eichenlaub, R; Metzler, M C

    1996-05-01

    In this paper we describe transformation of Clavibacter michiganensis subsp. sepedonicus, the potato ring rot bacterium, with plasmid vectors. Three of the plasmids used, pDM100, pDM302, and pDM306, contain the origin of replication from pCM1, a native plasmid of C. michiganensis subsp. michiganensis. We constructed two new cloning vectors, pHN205 and pHN216, by using the origin of replication of pCM2, another native plasmid of C. michiganensis subsp. michiganensis. Plasmids pDM302, pHN205, and pHN216 were stably maintained without antibiotic selection in various strains of C. michiganensis subsp. sepedonicus. We observed that for a single plasmid, different strains of C. michiganensis subsp. sepedonicus showed significantly different transformation efficiencies. We also found unexplained strain-to-strain differences in stability with various plasmid constructions containing different arrangements of antibiotic resistance genes and origins of replication. We examined the effect of a number of factors on transformation efficiency. The best transformation efficiencies were obtained when C. michiganensis subsp. sepedonicus cells were grown on DM agar plates, harvested during the early exponential growth phase, and used fresh (without freezing) for electroporation. The maximal transformation efficiency obtained was 4.6 x 10(4) CFU/microgram of pHN216 plasmid DNA. To demonstrate the utility of this transformation system, we cloned a beta-1,4-endoglucanase-encoding gene from C. michiganensis subsp. sepedonicus into pHN216. When this construction, pHN216:C8, was electroporated into competent cells of a cellulase-deficient mutant, it restored cellulase production to almost wild-type levels.

  20. Zymomonas mobilis: a bacterium for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Baratti, J.C.; Bu' Lock, J.D.

    1986-01-01

    Zymomonas mobilis is a facultative anaerobic gram negative bacterium first isolated in tropical countries from alcoholic beverages like the African palm wine, the Mexican pulque and also as a contaminant of cider (cider sickness) or beer in the European countries. It is one of the few facultative anaerobic bacteria degrading glucose by the Entner-Doudoroff pathway usually found in strictly aerobic microorganisms. Some work was devoted to this bacterium in the 50s and 60s and was reviewed by Swings and De Ley in their classical paper published in 1977. During the 70s there was very little work on the bacterium until 1979 and the first report by the Australian group of P.L. Rogers on the great potentialities of Z. mobilis for ethanol production. At that time the petroleum crisis had led the developed countries to search for alternative fuel from renewable resources. The Australian group clearly demonstrated the advantages of the bacterium compared to the yeasts traditionally used for the alcoholic fermentation. As a result, there was a considerable burst in the Zymomonas literature which started from nearly zero in the late 70s to attain 70 papers published in the field in 1984. In this article, papers published from 1982 to 1986 are reviewed.

  1. Overexpression and purification of halophilic proteins in Haloferax volcanii

    OpenAIRE

    Allers, Thorsten

    2010-01-01

    Halophilic enzymes function optimally at high salt concentrations and are active at low water availability. Such conditions are encountered at elevated concentrations of solutes such as salts and sugars, and at high concentrations of organic solvents. However, expression in heterologous hosts such as Escherichia coli can cause problems, since halophilic proteins typically misfold and aggregate in conditions of low ionic strength. We have harnessed the sophisticated genetic tools available for...

  2. Prospects for robust biocatalysis: engineering of novel specificity in a halophilic amino acid dehydrogenase.

    Science.gov (United States)

    Munawar, Nayla; Engel, Paul C

    2013-01-01

    Heat- and solvent-tolerant enzymes from halophiles, potentially important industrially, offer a robust framework for protein engineering, but few solved halophilic structures exist to guide this. Homology modelling has guided mutations in glutamate dehydrogenase (GDH) from Halobacterium salinarum to emulate conversion of a mesophilic GDH to a methionine dehydrogenase. Replacement of K89, A163 and S367 by leucine, glycine and alanine converted halophilic GDH into a dehydrogenase accepting L-methionine, L-norleucine and L-norvaline as substrates. Over-expression in the halophilic expression host Haloferax volcanii and three-step purification gave ~98 % pure protein exhibiting maximum activity at pH 10. This enzyme also showed enhanced thermostability and organic solvent tolerance even at 70 °C, offering a biocatalyst resistant to harsh industrial environments. To our knowledge, this is the first reported amino acid specificity change engineered in a halophilic enzyme, encouraging use of mesophilic models to guide engineering of novel halophilic biocatalysts for industrial application. Calibrated gel filtration experiments show that both the mutant and the wild-type enzyme are stable hexamers.

  3. The comparison of pyrosequencing molecular Gram stain, culture, and conventional Gram stain for diagnosing orthopaedic infections.

    Science.gov (United States)

    Kobayashi, Naomi; Bauer, Thomas W; Tuohy, Marion J; Lieberman, Isador H; Krebs, Viktor; Togawa, Daisuke; Fujishiro, Takaaki; Procop, Gary W

    2006-08-01

    We have developed a combined real-time PCR and pyrosequencing assay that successfully differentiated the vast majority of gram-positive and gram-negative bacteria when bacterial isolates were tested. The purpose of this study was to evaluate this assay on clinical specimens obtained from orthopedic surgeries, and to prospectively compare the results of "molecular Gram stain" with culture and conventional direct Gram stain. Forty-five surgical specimens were obtained from patients who underwent orthopedic surgery procedures. The DNA was extracted and a set of broad-range PCR primers that targeted a part of the 16S rDNA gene was used for pan-bacterial PCR. The amplicons were submitted for pyrosequencing and the resulting molecular Gram stain characteristics were recorded. Culture and direct Gram staining were performed using standard methods for all cases. Surgical specimens were reviewed histologically for all cases that had a discrepancy between culture and molecular results. There was an 86.7% (39/45) agreement between the traditional and molecular methods. In 12/14 (85.7%) culture-proven cases of bacterial infection, molecular Gram stain characteristics were in agreement with the culture results, while the conventional Gram stain result was in agreement only for five cases (35.7%). In the 31 culture negative cases, 27 cases were also PCR negative, whereas 4 were PCR positive. Three of these were characterized as gram negative and one as gram positive by this molecular method. Molecular determination of the Gram stain characteristics of bacteria that cause orthopedic infections may be achieved, in most instances, by this method. Further studies are necessary to understand the clinical importance of PCR-positive/culture-negative results.

  4. Stoichiometric and kinetic analysis of extreme halophilic Archaea on various substrates in a corrosion resistant bioreactor.

    Science.gov (United States)

    Lorantfy, Bettina; Seyer, Bernhard; Herwig, Christoph

    2014-01-25

    Extreme halophilic Archaea are extremophile species which can thrive in hypersaline environments of up to 3-5 M sodium chloride concentration. Although their ecology and physiology are widely identified on the microbiological level, little emphasis has been laid on quantitative bioprocess development with extreme halophiles. The goal of this study was to establish, on the one hand, a methodological basis for quantitative bioprocess analysis of extreme halophilic Archaea with an extreme halophilic strain as an example. Firstly, as a novel usage, a corrosion resistant bioreactor setup for extreme halophiles has been implemented. Then, paying special attention to total bioprocess quantification approaches, an indirect method for biomass quantification using on-line process signals was introduced. Subsequently, robust quantitative data evaluation methods for halophiles could be developed, providing defined and controlled cultivation conditions in the bioreactor and therefore obtaining suitable quality of on-line as well as off-line datasets. On the other hand, new physiological results of extreme halophiles in bioreactor have also been obtained based on the quantitative methodological tools. For the first time, quantitative data on stoichiometry and kinetics were collected and evaluated on different carbon sources. The results on various substrates were interpreted, with proposed metabolic mechanisms, by linking to the reported primary carbon metabolism of extreme halophilic Archaea. Moreover, results of chemostat cultures demonstrated that extreme halophilic organisms show Monod-kinetics on different sole carbon sources. A diauxic growth pattern was described on a mixture of substrates in batch cultivations. In addition, the methodologies presented here enable one to characterize the utilized strain Haloferax mediterranei (HFX) as a potential new host organism. Thus, this study offers a strong methodological basis as well as a fundamental physiological assessment for

  5. Bacillus isabeliae sp. nov., a halophilic bacterium isolated from a sea salt evaporation pond.

    Science.gov (United States)

    Albuquerque, Luciana; Tiago, Igor; Taborda, Marco; Nobre, M Fernanda; Veríssimo, António; da Costa, Milton S

    2008-01-01

    A low-G+C, Gram-positive isolate, designated strain CVS-8(T), was isolated from a sea salt evaporation pond on the Island of Sal in the Cape Verde Archipelago. This organism was found to be a catalase- and oxidase-positive, non-motile, spore-forming, aerobic, curved rod-shaped organism with an optimum growth temperature of about 35-37 degrees C and an optimum pH between 7.5 and 8.0. Optimal growth occurred in media containing 4-6% (w/v) NaCl and no growth occurred in medium without NaCl. The cell-wall peptidoglycan was of the A1gamma type with meso-diaminopimelic acid, the major respiratory quinone was MK-7, the major fatty acids were iso-15:0, 16:0, anteiso-15:0 and iso-16:0 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminoglycophospholipid. The G+C content of the DNA was 37.9 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain CVS-8(T) represented a novel species of the genus Bacillus, the highest levels of sequence similarity (mean pairwise similarity values of approximately 97.5 %) being found with respect to the type strains of Bacillus shackletonii and Bacillus acidicola. On the basis of the phylogenetic, physiological and biochemical data, strain CVS-8(T) represents a novel species of the genus Bacillus, for which the name Bacillus isabeliae sp. nov. is proposed. The type strain is CVS-8(T) (=LMG 22838(T)=CIP 108578(T)).

  6. Initiation of chromosomal replication in predatory bacterium Bdellovibrio bacteriovorus

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    Lukasz Makowski

    2016-11-01

    Full Text Available Bdellovibrio bacteriovorus is a small Gram-negative predatory bacterium that attacks other Gram-negative bacteria, including many animal, human, and plant pathogens. This bacterium exhibits a peculiar biphasic life cycle during which two different types of cells are produced: non-replicating highly motile cells (the free-living phase and replicating cells (the intracellular-growth phase. The process of chromosomal replication in B. bacteriovorus must therefore be temporally and spatially regulated to ensure that it is coordinated with cell differentiation and cell cycle progression. Recently, B. bacteriovorus has received considerable research interest due to its intriguing life cycle and great potential as a prospective antimicrobial agent. Although we know that chromosomal replication in bacteria is mainly regulated at the initiation step, no data exists about this process in B. bacteriovorus. We report the first characterization of key elements of initiation of chromosomal replication – DnaA protein and oriC region from the predatory bacterium, B. bacteriovorus. In vitro studies using different approaches demonstrate that the B. bacteriovorus oriC (BdoriC is specifically bound and unwound by the DnaA protein. Sequence comparison of the DnaA-binding sites enabled us to propose a consensus sequence for the B. bacteriovorus DnaA box (5’-NN(A/TTCCACA-3’. Surprisingly, in vitro analysis revealed that BdoriC is also bound and unwound by the host DnaA proteins (relatively distantly related from B. bacteriovorus. We compared the architecture of the DnaA–oriC complexes (orisomes in homologous (oriC and DnaA from B. bacteriovorus and heterologous (BdoriC and DnaA from prey, E. coli or P. aeruginosa systems. This work provides important new entry points toward improving our understanding of the initiation of chromosomal replication in this predatory bacterium.

  7. The rapid isolation of mutants of some Gram-positive bacteria

    International Nuclear Information System (INIS)

    Dijkhuizen, L.; Keijer, L.

    1981-01-01

    In this communication the authors describe a method for isolating at high frequency independent mutants of a number of Gram-positive bacteria. The method was originally developed for use with an Arthrobacter sp. and appears to work best with this and other coryneform bacteria. All the bacteria used were from the culture collections maintained at the University of Warwick or the Centre for Applied Microbiological Research. For mutagenesis using UV light, cells were grown in complex media and used while still in the logarithmic phase of growth. Details of the irradiation procedure are given in the text. (Auth.)

  8. The Mechanisms of Virulence Regulation by Small Noncoding RNAs in Low GC Gram-Positive Pathogens

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    Stephanie Pitman

    2015-12-01

    Full Text Available The discovery of small noncoding regulatory RNAs (sRNAs in bacteria has grown tremendously recently, giving new insights into gene regulation. The implementation of computational analysis and RNA sequencing has provided new tools to discover and analyze potential sRNAs. Small regulatory RNAs that act by base-pairing to target mRNAs have been found to be ubiquitous and are the most abundant class of post-transcriptional regulators in bacteria. The majority of sRNA studies has been limited to E. coli and other gram-negative bacteria. However, examples of sRNAs in gram-positive bacteria are still plentiful although the detailed gene regulation mechanisms behind them are not as well understood. Strict virulence control is critical for a pathogen’s survival and many sRNAs have been found to be involved in that process. This review outlines the targets and currently known mechanisms of trans-acting sRNAs involved in virulence regulation in various gram-positive pathogens. In addition, their shared characteristics such as CU interaction motifs, the role of Hfq, and involvement in two-component regulators, riboswitches, quorum sensing, or toxin/antitoxin systems are described.

  9. Effect of silver/copper and copper oxide nanoparticle powder on growth of Gram-negative and Gram-positive bacteria and their toxicity against the normal human dermal fibroblasts

    International Nuclear Information System (INIS)

    Peszke, Jerzy; Nowak, Anna; Szade, Jacek; Szurko, Agnieszka; Zygadło, Dorota; Michałowska, Marlena; Krzyściak, Paweł; Zygoń, Patrycja; Ratuszna, Alicja; Ostafin, Marek M.

    2016-01-01

    Engineered nanomaterials, especially metallic nanoparticles, are the most popular system applied in daily life products. The study of their biological and toxicity properties seems to be indispensable. In this paper, we present results of biological activity of Ag/Cu nanoparticles. These nanoparticles show more promising killing/inhibiting properties on Gram-negative bacteria than for Gram-positive ones. The Gram-negative bacteria show strong effect already at the concentration of 1 ppm after 15 min of incubation. Moreover, in vitro tests of toxicity made on normal human dermal fibroblast cultures showed that after 72 h of incubation with Ag/Cu nanoparticles, they are less toxic then Cu 2 O/CuO nanoparticles.

  10. Effect of silver/copper and copper oxide nanoparticle powder on growth of Gram-negative and Gram-positive bacteria and their toxicity against the normal human dermal fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Peszke, Jerzy; Nowak, Anna, E-mail: ana.maria.nowak@gmail.com; Szade, Jacek; Szurko, Agnieszka; Zygadło, Dorota; Michałowska, Marlena [University of Silesia, A. Chelkowski Institute of Physics (Poland); Krzyściak, Paweł [Jagiellonian University Medical College, Department of Mycology Chair of Microbiology (Poland); Zygoń, Patrycja [Czestochowa University of Technology, Institute of Materials Engineering (Poland); Ratuszna, Alicja [University of Silesia, A. Chelkowski Institute of Physics (Poland); Ostafin, Marek M. [Department of Microbiology University of Agriculture (Poland)

    2016-12-15

    Engineered nanomaterials, especially metallic nanoparticles, are the most popular system applied in daily life products. The study of their biological and toxicity properties seems to be indispensable. In this paper, we present results of biological activity of Ag/Cu nanoparticles. These nanoparticles show more promising killing/inhibiting properties on Gram-negative bacteria than for Gram-positive ones. The Gram-negative bacteria show strong effect already at the concentration of 1 ppm after 15 min of incubation. Moreover, in vitro tests of toxicity made on normal human dermal fibroblast cultures showed that after 72 h of incubation with Ag/Cu nanoparticles, they are less toxic then Cu{sub 2}O/CuO nanoparticles.

  11. Factors Determining the Biodiversity of Halophilic Microorganisms on Historic Masonry Buildings

    Science.gov (United States)

    Otlewska, Anna; Adamiak, Justyna; Stryszewska, Teresa; Kańka, Stanisław; Gutarowska, Beata

    2017-01-01

    The aim of the present study was to obtain insights into the relationship between the chemical (salt content and pH) and physico-mechanical (humidity and compressive strength) properties of mineral-based materials from historic buildings with salt efflorescence and the growth and biodiversity of halophilic microorganisms. Samples were mainly characterized by pH 6.5–8.5 and a moisture content of between 0.12 and 3.3%. Significant variations were also found in the salt content (sulfates, chlorides, and nitrates) of the materials. An SEM/EDS analysis of material surfaces revealed the presence of halite, calcite, gypsum, sodium sulfate, and potassium-sodium sulfate. Culture-dependent and culture-independent (clone library construction) approaches were both applied to detect halophilic microorganisms. Results derived from culturable methods and the materials analysis revealed a correlation between the total halophile count and pH value as well as sulfate content. A correlation was not observed between the concentration of chlorides or nitrates and the number of halophilic microorganisms. The materials studied were inhabited by the culturable halophilic bacteria Halobacillus sp., Virgibacillus sp., and Marinococcus sp. as well as the yeast Sterigmatomyces sp., which was isolated for the first time from mineral materials. Culture-independent techniques revealed the following bacterial species: Salinibacterium, Salinisphaera, Rubrobacter, Rubricoccus, Halomonas, Halorhodospira, Solirubrobacter, Salinicoccus, and Salinibacter. Biodiversity was the highest in materials with high or moderate salinity. PMID:28592721

  12. Factors Determining the Biodiversity of Halophilic Microorganisms on Historic Masonry Buildings.

    Science.gov (United States)

    Otlewska, Anna; Adamiak, Justyna; Stryszewska, Teresa; Kańka, Stanisław; Gutarowska, Beata

    2017-06-24

    The aim of the present study was to obtain insights into the relationship between the chemical (salt content and pH) and physico-mechanical (humidity and compressive strength) properties of mineral-based materials from historic buildings with salt efflorescence and the growth and biodiversity of halophilic microorganisms. Samples were mainly characterized by pH 6.5-8.5 and a moisture content of between 0.12 and 3.3%. Significant variations were also found in the salt content (sulfates, chlorides, and nitrates) of the materials. An SEM/EDS analysis of material surfaces revealed the presence of halite, calcite, gypsum, sodium sulfate, and potassium-sodium sulfate. Culture-dependent and culture-independent (clone library construction) approaches were both applied to detect halophilic microorganisms. Results derived from culturable methods and the materials analysis revealed a correlation between the total halophile count and pH value as well as sulfate content. A correlation was not observed between the concentration of chlorides or nitrates and the number of halophilic microorganisms. The materials studied were inhabited by the culturable halophilic bacteria Halobacillus sp., Virgibacillus sp., and Marinococcus sp. as well as the yeast Sterigmatomyces sp., which was isolated for the first time from mineral materials. Culture-independent techniques revealed the following bacterial species: Salinibacterium, Salinisphaera, Rubrobacter, Rubricoccus, Halomonas, Halorhodospira, Solirubrobacter, Salinicoccus, and Salinibacter. Biodiversity was the highest in materials with high or moderate salinity.

  13. The complete genome of Zunongwangia profunda SM-A87 reveals its adaptation to the deep-sea environment and ecological role in sedimentary organic nitrogen degradation

    Directory of Open Access Journals (Sweden)

    Zhou Bai-Cheng

    2010-04-01

    Full Text Available Abstract Background Zunongwangia profunda SM-A87, which was isolated from deep-sea sediment, is an aerobic, gram-negative bacterium that represents a new genus of Flavobacteriaceae. This is the first sequenced genome of a deep-sea bacterium from the phylum Bacteroidetes. Results The Z. profunda SM-A87 genome has a single 5 128 187-bp circular chromosome with no extrachromosomal elements and harbors 4 653 predicted protein-coding genes. SM-A87 produces a large amount of capsular polysaccharides and possesses two polysaccharide biosynthesis gene clusters. It has a total of 130 peptidases, 61 of which have signal peptides. In addition to extracellular peptidases, SM-A87 also has various extracellular enzymes for carbohydrate, lipid and DNA degradation. These extracellular enzymes suggest that the bacterium is able to hydrolyze organic materials in the sediment, especially carbohydrates and proteinaceous organic nitrogen. There are two clustered regularly interspaced short palindromic repeats in the genome, but their spacers do not match any sequences in the public sequence databases. SM-A87 is a moderate halophile. Our protein isoelectric point analysis indicates that extracellular proteins have lower predicted isoelectric points than intracellular proteins. SM-A87 accumulates organic osmolytes in the cell, so its extracelluar proteins are more halophilic than its intracellular proteins. Conclusion Here, we present the first complete genome of a deep-sea sedimentary bacterium from the phylum Bacteroidetes. The genome analysis shows that SM-A87 has some common features of deep-sea bacteria, as well as an important capacity to hydrolyze sedimentary organic nitrogen.

  14. Experience With Rapid Microarray-Based Diagnostic Technology and Antimicrobial Stewardship for Patients With Gram-Positive Bacteremia.

    Science.gov (United States)

    Neuner, Elizabeth A; Pallotta, Andrea M; Lam, Simon W; Stowe, David; Gordon, Steven M; Procop, Gary W; Richter, Sandra S

    2016-11-01

    OBJECTIVE To describe the impact of rapid diagnostic microarray technology and antimicrobial stewardship for patients with Gram-positive blood cultures. DESIGN Retrospective pre-intervention/post-intervention study. SETTING A 1,200-bed academic medical center. PATIENTS Inpatients with blood cultures positive for Staphylococcus aureus, Enterococcus faecalis, E. faecium, Streptococcus pneumoniae, S. pyogenes, S. agalactiae, S. anginosus, Streptococcus spp., and Listeria monocytogenes during the 6 months before and after implementation of Verigene Gram-positive blood culture microarray (BC-GP) with an antimicrobial stewardship intervention. METHODS Before the intervention, no rapid diagnostic technology was used or antimicrobial stewardship intervention was undertaken, except for the use of peptide nucleic acid fluorescent in situ hybridization and MRSA agar to identify staphylococcal isolates. After the intervention, all Gram-positive blood cultures underwent BC-GP microarray and the antimicrobial stewardship intervention consisting of real-time notification and pharmacist review. RESULTS In total, 513 patients with bacteremia were included in this study: 280 patients with S. aureus, 150 patients with enterococci, 82 patients with stretococci, and 1 patient with L. monocytogenes. The number of antimicrobial switches was similar in the pre-BC-GP (52%; 155 of 300) and post-BC-GP (50%; 107 of 213) periods. The time to antimicrobial switch was significantly shorter in the post-BC-GP group than in the pre-BC-GP group: 48±41 hours versus 75±46 hours, respectively (P<.001). The most common antimicrobial switch was de-escalation and time to de-escalation, was significantly shorter in the post-BC-GP group than in the pre-BC-GP group: 53±41 hours versus 82±48 hours, respectively (P<.001). There was no difference in mortality or hospital length of stay as a result of the intervention. CONCLUSIONS The combination of a rapid microarray diagnostic test with an antimicrobial

  15. Antimicrobial resistance in Gram-positive bacteria from Timorese River Buffalo (Bubalus bubalis) skin microbiota.

    Science.gov (United States)

    Oliveira, Manuela; Monteiro, José L; Rana, Sílvia; Vilela, Cristina L

    2010-06-01

    The Timorese River Buffalo (Bubalus bubalis) plays a major role in the East Timor economy, as it is an important source of animal protein in human nutrition. They are widely spread throughout the country and are in direct contact with the populations. In spite of this proximity, information on their microbiota is scarce. This work aimed at characterizing the skin microbiota of the East Timorese River Buffalo and its antimicrobial resistance profile. Skin swab samples were taken from 46 animals in surveys conducted in three farms located in "Suco de Nairete", Lospalos district, during July and August 2006. Bacteria were isolated and identified according to conventional microbiological procedures. A total of 456 isolates were obtained, including Gram-positive (n = 243) and Gram-negative (n = 213) bacteria. Due to their importance as potential pathogens and as vehicles for antimicrobial resistance transmission, Gram-positive cocci (n = 27) and bacilli (n = 77) isolates were further characterized, and their antimicrobial resistance profile determined by the disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. This study shows the high bacterial diversity of B. bubalis skin microbiota, representing an important first step towards understanding its importance and epidemiologic role in animal health. It also points out the potential role of these animals as vectors of antimicrobial resistant bacteria dissemination and the importance of antimicrobial resistance monitoring in developing countries.

  16. Structural adaptation of extreme halophilic proteins through decrease of conserved hydrophobic contact surface

    Science.gov (United States)

    2011-01-01

    Background Halophiles are extremophilic microorganisms growing optimally at high salt concentrations. There are two strategies used by halophiles to maintain proper osmotic pressure in their cytoplasm: accumulation of molar concentrations of potassium and chloride with extensive adaptation of the intracellular macromolecules ("salt-in" strategy) or biosynthesis and/or accumulation of organic osmotic solutes ("osmolyte" strategy). Our work was aimed at contributing to the understanding of the shared molecular mechanisms of protein haloadaptation through a detailed and systematic comparison of a sample of several three-dimensional structures of halophilic and non-halophilic proteins. Structural differences observed between the "salt-in" and the mesophilic homologous proteins were contrasted to those observed between the "osmolyte" and mesophilic pairs. Results The results suggest that haloadaptation strategy in the presence of molar salt concentration, but not of osmolytes, necessitates a weakening of the hydrophobic interactions, in particular at the level of conserved hydrophobic contacts. Weakening of these interactions counterbalances their strengthening by the presence of salts in solution and may help the structure preventing aggregation and/or loss of function in hypersaline environments. Conclusions Considering the significant increase of biotechnology applications of halophiles, the understanding of halophilicity can provide the theoretical basis for the engineering of proteins of great interest because stable at concentrations of salts that cause the denaturation or aggregation of the majority of macromolecules. PMID:22192175

  17. Structural adaptation of extreme halophilic proteins through decrease of conserved hydrophobic contact surface

    Directory of Open Access Journals (Sweden)

    Siglioccolo Alessandro

    2011-12-01

    Full Text Available Abstract Background Halophiles are extremophilic microorganisms growing optimally at high salt concentrations. There are two strategies used by halophiles to maintain proper osmotic pressure in their cytoplasm: accumulation of molar concentrations of potassium and chloride with extensive adaptation of the intracellular macromolecules ("salt-in" strategy or biosynthesis and/or accumulation of organic osmotic solutes ("osmolyte" strategy. Our work was aimed at contributing to the understanding of the shared molecular mechanisms of protein haloadaptation through a detailed and systematic comparison of a sample of several three-dimensional structures of halophilic and non-halophilic proteins. Structural differences observed between the "salt-in" and the mesophilic homologous proteins were contrasted to those observed between the "osmolyte" and mesophilic pairs. Results The results suggest that haloadaptation strategy in the presence of molar salt concentration, but not of osmolytes, necessitates a weakening of the hydrophobic interactions, in particular at the level of conserved hydrophobic contacts. Weakening of these interactions counterbalances their strengthening by the presence of salts in solution and may help the structure preventing aggregation and/or loss of function in hypersaline environments. Conclusions Considering the significant increase of biotechnology applications of halophiles, the understanding of halophilicity can provide the theoretical basis for the engineering of proteins of great interest because stable at concentrations of salts that cause the denaturation or aggregation of the majority of macromolecules.

  18. Distinction of Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts with a selection medium.

    Science.gov (United States)

    Tsukatani, Tadayuki; Suenaga, Hikaru; Higuchi, Tomoko; Shiga, Masanobu; Noguchi, Katsuya; Matsumoto, Kiyoshi

    2011-01-01

    Bacteria are fundamentally divided into two groups: Gram-positive and Gram-negative. Although the Gram stain and other techniques can be used to differentiate these groups, some issues exist with traditional approaches. In this study, we developed a method for differentiating Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of the tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt} (WST-8) via 2-methyl-1,4-napthoquinone with a selection medium. We optimized the composition of the selection medium to allow the growth of Gram-negative bacteria while inhibiting the growth of Gram-positive bacteria. When the colorimetric viability assay was carried out in a selection medium containing 0.5µg/ml crystal violet, 5.0 µg/ml daptomycin, and 5.0µg/ml vancomycin, the reduction in WST-8 by Gram-positive bacteria was inhibited. On the other hand, Gram-negative bacteria produced WST-8-formazan in the selection medium. The proposed method was also applied to determine the Gram staining characteristics of bacteria isolated from various foodstuffs. There was good agreement between the results obtained using the present method and those obtained using a conventional staining method. These results suggest that the WST-8 colorimetric assay with selection medium is a useful technique for accurately differentiating Gram-positive and -negative bacteria.

  19. Secretory phospholipase A2 in dromedary tears: a host defense against staphylococci and other gram-positive bacteria.

    Science.gov (United States)

    Ben Bacha, Abir; Abid, Islem

    2013-03-01

    The best known physiologic function of secreted phospholipase A2 (sPLA2) group IIA (sPLA2-IIA) is defense against bacterial infection through hydrolytic degradation of bacterial membrane phospholipids. In fact, sPLA2-IIA effectively kills Gram-positive bacteria and to a lesser extent Gram-negative bacteria and is considered a major component of the eye's innate immune defense system. The antibacterial properties of sPLA2 have been demonstrated in rabbit and human tears. In this report, we have analyzed the bactericidal activity of dromedary tears and the subsequently purified sPLA2 on several Gram-positive bacteria. Our results showed that the sPLA2 displays a potent bactericidal activity against all the tested bacteria particularly against the Staphylococcus strains when tested in the ionic environment of tears. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2. Interestingly, lysozyme purified from dromedary tears showed a significant bactericidal activity against Listeria monocytogene and Staphylococcus epidermidis, whereas the one purified from human tears displayed no activity against these two strains. We have also demonstrated that Ca(2+) is crucial for the activity of dromedary tear sPLA2 and to a less extent Mg(2+) ions. Given the presence of sPLA2 in tears and intestinal secretions, this enzyme may play a substantial role in innate mucosal and systemic bactericidal defenses against Gram-positive bacteria.

  20. The origin of a derived superkingdom: how a gram-positive bacterium crossed the desert to become an archaeon

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    Bourne Philip E

    2011-02-01

    Full Text Available Abstract Background The tree of life is usually rooted between archaea and bacteria. We have previously presented three arguments that support placing the root of the tree of life in bacteria. The data have been dismissed because those who support the canonical rooting between the prokaryotic superkingdoms cannot imagine how the vast divide between the prokaryotic superkingdoms could be crossed. Results We review the evidence that archaea are derived, as well as their biggest differences with bacteria. We argue that using novel data the gap between the superkingdoms is not insurmountable. We consider whether archaea are holophyletic or paraphyletic; essential to understanding their origin. Finally, we review several hypotheses on the origins of archaea and, where possible, evaluate each hypothesis using bioinformatics tools. As a result we argue for a firmicute ancestry for archaea over proposals for an actinobacterial ancestry. Conclusion We believe a synthesis of the hypotheses of Lake, Gupta, and Cavalier-Smith is possible where a combination of antibiotic warfare and viral endosymbiosis in the bacilli led to dramatic changes in a bacterium that resulted in the birth of archaea and eukaryotes. Reviewers This article was reviewed by Patrick Forterre, Eugene Koonin, and Gáspár Jékely

  1. Thusin, a novel two-component lantibiotic with potent antimicrobial activity against several Gram-positive pathogens

    Directory of Open Access Journals (Sweden)

    Bingyue Xin

    2016-07-01

    Full Text Available Due to the rapidly increasing prevalence of multidrug-resistant bacterial strains, the need for new antimicrobial drugs to treat infections has become urgent. Bacteriocins, which are antimicrobial peptides of bacterial origin, are considered potential alternatives to conventional antibiotics and have attracted widespread attention in recent years. Among these bacteriocins, lantibiotics, especially two-component lantibiotics, exhibit potent antimicrobial activity against some clinically relevant Gram-positive pathogens and have potential applications in the pharmaceutical industry. In this study, we characterized a novel two-component lantibiotic termed thusin that consists of Thsα, Thsβ and Thsβ' (mutation of Thsβ, A14G and that was isolated from a B. thuringiensis strain BGSC 4BT1. Thsα and Thsβ (or Thsβ' exhibit optimal antimicrobial activity at a 1:1 ratio and act sequentially to affect target cells, and they are all highly thermostable (100°C for 30 min and pH tolerant (pH 2.0 to 9.0. Thusin shows remarkable efficacy against all tested Gram-positive bacteria and greater activities than two known lantibiotics thuricin 4A-4 and ticin A4, and one antibiotic vancomycin against various bacterial pathogens (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus (MRSA, Staphylococcus sciuri, Enterococcus faecalis, and Streptococcus pneumoniae. Moreover, thusin is also able to inhibit the outgrowth of Bacillus cereus spores. The potent antimicrobial activity of thusin against some Gram-positive pathogens indicates that it has potential for the development of new drugs.

  2. Progress in decontamination by halophilic microorganisms in saline wastewater and soil

    International Nuclear Information System (INIS)

    Zhuang Xuliang; Han Zhen; Bai Zhihui; Zhuang Guoqiang; Shim Hojae

    2010-01-01

    Environments with high-salt concentrations are often populated by dense microbial communities. Halophilic microorganisms can be isolated from different saline environments and different strains even belonging to the same genus have various applications. Wastewater and soil rich in both organic matter and salt are difficult to treat using conventional microorganisms typically found in wastewater treatment and soil bioremediation facilities. Studies on decontaminative capabilities and decontamination pathways of organic contaminants (i.e., aromatic compounds benzoate, cinnamate, 3-phenylpropionate, 4-hydroxybenzoic acid), heavy metals (i.e., tellurium, vanadium), and nutrients in the biological treatment of saline wastewater and soil by halophilic microorganisms are discussed in this review. - Review on the decontaminative capabilities of halophilic microorganisms in saline wastewater and soil.

  3. Progress in decontamination by halophilic microorganisms in saline wastewater and soil

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang Xuliang, E-mail: xlzhuang@rcees.ac.c [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Bureau of Science and Technology for Resources and Environment, Chinese Academy of Sciences, Beijing 100864 (China); Han Zhen [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Bai Zhihui; Zhuang Guoqiang [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Shim Hojae [Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau (China)

    2010-05-15

    Environments with high-salt concentrations are often populated by dense microbial communities. Halophilic microorganisms can be isolated from different saline environments and different strains even belonging to the same genus have various applications. Wastewater and soil rich in both organic matter and salt are difficult to treat using conventional microorganisms typically found in wastewater treatment and soil bioremediation facilities. Studies on decontaminative capabilities and decontamination pathways of organic contaminants (i.e., aromatic compounds benzoate, cinnamate, 3-phenylpropionate, 4-hydroxybenzoic acid), heavy metals (i.e., tellurium, vanadium), and nutrients in the biological treatment of saline wastewater and soil by halophilic microorganisms are discussed in this review. - Review on the decontaminative capabilities of halophilic microorganisms in saline wastewater and soil.

  4. Characterization of a Neochlamydia-like Bacterium Associated with Epitheliocystis in Cultured Artic Char Salvelinus alpinus

    Science.gov (United States)

    Infections of branchial epithelium by intracellular gram-negative bacteria, termed epitheliocystis, have limited culture of Arctic char (Salvelinus alpinus). To characterize a bacterium associated with epitheliocystis in cultured char, gills were sampled for histopathologic examination, conventional...

  5. Colwellia agarivorans sp. nov., an agar-digesting marine bacterium isolated from coastal seawater

    Science.gov (United States)

    A novel Gram-stain-negative, facultatively anaerobic, yellowish and agar-digesting marine bacterium, designated strain QM50**T, was isolated from coastal seawater in an aquaculture site near Qingdao, China. Phylogenetic analysis based on 16S rDNA sequences revealed that the novel isolate represented...

  6. Treatment of gram-positive deep sternal wound infections in cardiac surgery -experiences with daptomycin-

    Directory of Open Access Journals (Sweden)

    Coskun Kasim O

    2011-09-01

    Full Text Available Abstract The reported incidence of deep sternal wound infection (DSWI after cardiac surgery is 0.4-5% with Staphylococcus aureus being the most common pathogen isolated from infected wound sternotomies and bacteraemic blood cultures. This infection is associated with a higher morbidity and mortality than other known aetiologies. Little is reported about the optimal antibiotic management. The aim of the study is to quantify the application of daptomycin treatment of DSWI due to gram-positive organisms post cardiac surgery. We performed an observational analysis in 23 cases of post sternotomy DSWI with gram-positive organisms February 2009 and September 2010. When the wound appeared viable and the microbiological cultures were negative, the technique of chest closure was individualised to the patient. The incidence of DSWI was 1.46%. The mean dose of daptomycin application was 4.4 ± 0.9 mg/kg/d and the average duration of the daptomycin application was 14.47 ± 7.33 days. In 89% of the patients VAC therapy was used. The duration from daptomycin application to sternal closure was 18 ± 13.9 days. The parameters of infection including, fibrinogen (p = 0.03, white blood cell count (p = 0.001 and C-reactive protein (p = 0.0001 were significantly reduced after daptomycin application. We had no mortality and wound healing was successfully achieved in all patients. Treatment of DSWI due to gram-positive organisms with a daptomycin-containing antibiotic regimen is safe, effective and promotes immediate improvement of local wound conditions. Based on these observations, daptomycin may offer a new treatment option for expediting surgical management of DSWI after cardiac surgery.

  7. Vibrio parahaemolyticus: A Review on the Pathogenesis, Prevalence and Advance Molecular Identification Techniques

    Directory of Open Access Journals (Sweden)

    Vengadesh eLetchumanan

    2014-12-01

    Full Text Available Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is found in estuarine, marine and coastal environments. Vibrio parahaemolyticus is the leading causal agent of human acute gastroenteritis following the consumption of raw, undercooked or mishandled marine products. In rare cases, Vibrio parahaemolyticus causes wound infection, ear infection or septicaemia in individuals with pre-existing medical conditions. Vibrio parahaemolyticus has two hemolysins virulence factors that are thermostable direct hemolysin (tdh-a pore-forming protein that contributes to the invasiveness of the bacterium in humans, and TDH-related hemolysin (trh, which plays a similar role as thermostable direct hemolysin (tdh in the disease pathogenesis. In addition, the bacterium is also encodes for adhesions and type III secretion systems (T3SS1 and T3SS2 to ensure its survival in the environment. This review aims at discussing the Vibrio parahemolyticus growth and characteristics, pathogenesis, prevalence and advances in molecular identification techniques.

  8. Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms.

    Science.gov (United States)

    Weissgram, Michaela; Gstöttner, Janina; Lorantfy, Bettina; Tenhaken, Raimund; Herwig, Christoph; Weber, Hedda K

    2015-06-08

    Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.

  9. Taxonomic study of extreme halophilic archaea isolated from the "Salar de Atacama", Chile.

    Science.gov (United States)

    Lizama, C; Monteoliva-Sánchez, M; Prado, B; Ramos-Cormenzana, A; Weckesser, J; Campos, V

    2001-11-01

    A large number of halophilic bacteria were isolated in 1984-1992 from the Atacama Saltern (North of Chile). For this study 82 strains of extreme halophilic archaea were selected. The characterization was performed by using the phenotypic characters including morphological, physiological, biochemical, nutritional and antimicrobial susceptibility test. The results, together with those from reference strains, were subjected to numerical analysis, using the Simple Matching (S(SM)) coefficient and clustered by the unweighted pair group method of association (UPGMA). Fifteen phena were obtained at an 70% similarity level. The results obtained reveal a high diversity among the halophilic archaea isolated. Representative strains from the phena were chosen to determine their DNA base composition and the percentage of DNA-DNA similarity compared to reference strains. The 16S rRNA studies showed that some of these strains constitutes a new taxa of extreme halophilic archaea.

  10. Morphological characterization of several strains of the rice-pathogenic bacterium Burkholderia glumae in North Sumatra

    Science.gov (United States)

    Hasibuan, M.; Safni, I.; Lisnawita; Lubis, K.

    2018-02-01

    Burkholderia glumae is a quarantine seed-borne bacterial pathogen causing panicle blight disease on rice. This pathogen has been detected in some locations in Java, and recently, farmers in North Sumatra have reported rice yield loss with symptoms similar with those on rice infeced by the rice-pathogenic bacterium B. glumae. This research was aimed to isolate several bacterial strains from several rice varieties in various locations in North Sumatra and characterize the morphology of the strains to detect and identify the unknown bacterial strains presumably B. glumae. Several rice seed varieties were collected from Medan and Deli Serdang Districts. The seed samples were extracted, isolated and purified, then grown in semi-selective media PPGA. The morphological characteristics of the bacterial strains were determined including Gram staining, bacterial colony’s and bacterial cell’s morphology. The results showed that of eleven strains isolated, two strains were Gram negative and nine strains were Gram positive. On the basis of colony morphology, all strains had circular form, flat elevation and cream colour while the colony margin varied, i.e. entire and undulate. Most strains had bacillus/rod shape (8 strains) and only 3 strains were coccus.

  11. Streptococcus mutans: a new Gram-positive paradigm?

    Science.gov (United States)

    Quivey, Robert G.; Koo, Hyun; Abranches, Jacqueline

    2013-01-01

    Despite the enormous contributions of the bacterial paradigms Escherichia coli and Bacillus subtilis to basic and applied research, it is well known that no single organism can be a perfect representative of all other species. However, given that some bacteria are difficult, or virtually impossible, to cultivate in the laboratory, that some are recalcitrant to genetic and molecular manipulation, and that others can be extremely dangerous to manipulate, the use of model organisms will continue to play an important role in the development of basic research. In particular, model organisms are very useful for providing a better understanding of the biology of closely related species. Here, we discuss how the lifestyle, the availability of suitable in vitro and in vivo systems, and a thorough understanding of the genetics, biochemistry and physiology of the dental pathogen Streptococcus mutans have greatly advanced our understanding of important areas in the field of bacteriology such as interspecies biofilms, competence development and stress responses. In this article, we provide an argument that places S. mutans, an organism that evolved in close association with the human host, as a novel Gram-positive model organism. PMID:23393147

  12. Halophilic and haloalkaliphilic sulfur-oxidizing bacteria

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.; Robertson, L.A.; Kuenen, J.G.; Muntyan, M.S.; Muyzer, G.; Rosenberg, E.; DeLong, F.; Delong, E.; Lory, S.; Stackebrandt, E.; Thompson, F.

    2013-01-01

    Chemotrophic sulfur-oxidizing bacteria (SOB) represent an important functional group of microorganisms responsible for the dark oxidation of reduced sulfur compounds generated by sulfidogens. Until recently, only a single genus of halophilic SOB (Halothiobacillus) has been described, and nothing was

  13. Changes of the Quinolones Resistance to Gram-positive Cocci Isolated during the Past 8 Years in the First Bethune Hospital

    Science.gov (United States)

    Xu, Jiancheng; Chen, Qihui; Yao, Hanxin; Zhou, Qi

    This study was to investigate the quinolones resistance to gram-positive cocci isolated in the First Bethune Hospital during the past 8 years. Disk diffusion test was used to study the antimicrobial resistance. The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI). The rates of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococci (MRCNS) were 50.8%∼83.3% and 79.4%∼81.5%during the past 8 years, respectively. In recent 8 years, the quinolones resistance to gram-positive cocci had increased. Monitoring of the quinolones resistance to gram-positive cocci should be strengthened. The change of the antimicrobial resistance should be investigated in order to guide rational drug usage in the clinic and prevent bacterial strain of drug resistance from being transmitted.

  14. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

    Science.gov (United States)

    Takahashi, Masateru; Takahashi, Etsuko; Joudeh, Luay I; Marini, Monica; Das, Gobind; Elshenawy, Mohamed M; Akal, Anastassja; Sakashita, Kosuke; Alam, Intikhab; Tehseen, Muhammad; Sobhy, Mohamed A; Stingl, Ulrich; Merzaban, Jasmeen S; Di Fabrizio, Enzo; Hamdan, Samir M

    2018-01-24

    The deep-sea brines of the Red Sea are remote and unexplored environments characterized by high temperatures, anoxic water, and elevated concentrations of salt and heavy metals. This environment provides a rare system to study the interplay between halophilic and thermophilic adaptation in biologic macromolecules. The present article reports the first DNA polymerase with halophilic and thermophilic features. Biochemical and structural analysis by Raman and circular dichroism spectroscopy showed that the charge distribution on the protein's surface mediates the structural balance between stability for thermal adaptation and flexibility for counteracting the salt-induced rigid and nonfunctional hydrophobic packing. Salt bridge interactions via increased negative and positive charges contribute to structural stability. Salt tolerance, conversely, is mediated by a dynamic structure that becomes more fixed and functional with increasing salt concentration. We propose that repulsive forces among excess negative charges, in addition to a high percentage of negatively charged random coils, mediate this structural dynamism. This knowledge enabled us to engineer a halophilic version of KOD DNA polymerase.-Takahashi, M., Takahashi, E., Joudeh, L. I., Marini, M., Das, G., Elshenawy, M. M., Akal, A., Sakashita, K., Alam, I., Tehseen, M., Sobhy, M. A., Stingl, U., Merzaban, J. S., Di Fabrizio, E., Hamdan, S. M. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

  15. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea

    KAUST Repository

    Takahashi, Masateru; Takahashi, Etsuko; Joudeh, Luay I.; Marini, Monica; Das, Gobind; Elshenawy, Mohamed; Akal, Anastassja; Sakashita, Kosuke; Alam, Intikhab; Tehseen, Muhammad; Sobhy, Mohamed Abdelmaboud; Stingl, Ulrich; Merzaban, Jasmeen; Di Fabrizio, Enzo M.; Hamdan, Samir

    2018-01-01

    The deep-sea brines of the Red Sea are remote and unexplored environments characterized by high temperatures, anoxic water, and elevated concentrations of salt and heavy metals. This environment provides a rare system to study the interplay between halophilic and thermophilic adaptation in biologic macromolecules. The present article reports the first DNA polymerase with halophilic and thermophilic features. Biochemical and structural analysis by Raman and circular dichroism spectroscopy showed that the charge distribution on the protein’s surface mediates the structural balance between stability for thermal adaptation and flexibility for counteracting the salt-induced rigid and nonfunctional hydrophobic packing. Salt bridge interactions via increased negative and positive charges contribute to structural stability. Salt tolerance, conversely, is mediated by a dynamic structure that becomes more fixed and functional with increasing salt concentration. We propose that repulsive forces among excess negative charges, in addition to a high percentage of negatively charged random coils, mediate this structural dynamism. This knowledge enabled us to engineer a halophilic version of KOD DNA polymerase.—Takahashi, M., Takahashi, E., Joudeh, L. I., Marini, M., Das, G., Elshenawy, M. M., Akal, A., Sakashita, K., Alam, I., Tehseen, M., Sobhy, M. A., Stingl, U., Merzaban, J. S., Di Fabrizio, E., Hamdan, S. M. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

  16. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea

    KAUST Repository

    Takahashi, Masateru

    2018-01-24

    The deep-sea brines of the Red Sea are remote and unexplored environments characterized by high temperatures, anoxic water, and elevated concentrations of salt and heavy metals. This environment provides a rare system to study the interplay between halophilic and thermophilic adaptation in biologic macromolecules. The present article reports the first DNA polymerase with halophilic and thermophilic features. Biochemical and structural analysis by Raman and circular dichroism spectroscopy showed that the charge distribution on the protein’s surface mediates the structural balance between stability for thermal adaptation and flexibility for counteracting the salt-induced rigid and nonfunctional hydrophobic packing. Salt bridge interactions via increased negative and positive charges contribute to structural stability. Salt tolerance, conversely, is mediated by a dynamic structure that becomes more fixed and functional with increasing salt concentration. We propose that repulsive forces among excess negative charges, in addition to a high percentage of negatively charged random coils, mediate this structural dynamism. This knowledge enabled us to engineer a halophilic version of KOD DNA polymerase.—Takahashi, M., Takahashi, E., Joudeh, L. I., Marini, M., Das, G., Elshenawy, M. M., Akal, A., Sakashita, K., Alam, I., Tehseen, M., Sobhy, M. A., Stingl, U., Merzaban, J. S., Di Fabrizio, E., Hamdan, S. M. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.

  17. Mechanism of action of recombinant acc-royalisin from royal jelly of Asian honeybee against gram-positive bacteria.

    Directory of Open Access Journals (Sweden)

    Lirong Shen

    Full Text Available The antibacterial activity of royalisin, an antimicrobial peptide from the royal jelly produced by honeybees, has been addressed extensively. However, its mechanism of action remains unclear. In this study, a recombinant royalisin, RAcc-royalisin from the royal jelly of Asian honeybee Apis cerana cerana, was expressed by fusing with glutathione S-transferase (GST in Escherichia coli BL21, isolated and purified. The agar dilution assays with inhibition zone showed that RAcc-royalisin, similar to nisin, inhibits the growth of Gram-positive bacteria. The antibacterial activity of RAcc-royalisin was associated with its concentration, and was weakened by heat treatment ranging from 55°C to 85°C for 15 min. Both RAcc-royalisin and nisin exhibited the minimum inhibitory concentrations (MIC of 62.5 µg/ml, 125 µg/ml, and 250 µg/ml against Gram-positive bacterial strains, Bacillus subtilis and Micrococcus flavus and Staphyloccocus aureus in the microplate assay, respectively. However, RAcc-royalisin did not show antimicrobial activity against tested Gram-negative bacterial and fungal strains. The antibacterial activity of RAcc-royalisin agrees well with the decrease in bacterial cell hydrophobicity, the leakage of 260-nm absorbing materials, and the observation by transmission electron microscopy, all indicating that RAcc-royalisin induced the disruption and dysfunction of cell walls and membranes. This is the first report detailing the antibacterial mechanism of royalisin against Gram-positive bacteria, and provides insight into the application of recombinant royalisin in food and pharmaceutical industries as an antimicrobial agent.

  18. A Trojan-Horse Strategy Including a Bacterial Suicide Action for the Efficient Use of a Specific Gram-Positive Antibiotic on Gram-Negative Bacteria.

    Science.gov (United States)

    Schalk, Isabelle J

    2018-05-10

    In the alarming context of rising bacterial antibiotic resistance, there is an urgent need to discover new antibiotics or increase and/or enlarge the activity of those currently in use. The need for new antibiotics is even more urgent in the case of Gram-negative bacteria, such as Acinetobacter, Pseudomonas, and Enterobacteria, which have become resistant to many antibiotics and have an outer membrane with very low permeability to drugs. Vectorization of antibiotics using siderophores may be a solution to bypass such a bacterial wall: the drugs use the iron transporters of the outer membrane as gates to enter bacteria in a Trojan-horse strategy. Designing siderophore-antibiotics that can cross outer membranes has become almost routine, but their transport across the inner membrane is still a limiting step, as well as a strategy that allows dissociation of the antibiotic from the siderophore once inside the bacteria. Liu et al. ( J. Med. Chem. 2018 , DOI: 10.1021/acs.jmedchem.8b00218 ) report the synthesis of a siderophore-cephalosporin compound and demonstrate that β-lactams, such as cephalosporins, can serve as β-lactamase-triggered releasable linkers to allow intracellular delivery of Gram-positive antibiotics to Gram-negative bacteria.

  19. Antibacterial activity and interactions of plant essential oil combinations against Gram-positive and Gram-negative bacteria

    Directory of Open Access Journals (Sweden)

    Cristina Anamaria Semeniuc

    2017-04-01

    Full Text Available The aim of this study was to compare the antibacterial effects of several essential oils (EOs alone and in combination against different Gram-positive and Gram-negative bacteria associated with food products. Parsley, lovage, basil, and thyme EOs, as well as their mixtures (1:1, v/v, were tested against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium. The inhibitory effects ranged from strong (thyme EO against E. coli to no inhibition (parsley EO against P. aeruginosa. Thyme EO exhibited strong (against E. coli, moderate (against S. typhimurium and B. cereus, or mild inhibitory effects (against P. aeruginosa and S. aureus, and basil EO showed mild (against E. coli and B. cereus or no inhibitory effects (against S. typhimurium, P. aeruginosa, and S. aureus. Parsley and lovage EOs revealed no inhibitory effects against all tested strains. Combinations of lovage/thyme and basil/thyme EOs displayed antagonistic effects against all bacteria, parsley/thyme EOs against B. cereus, S. aureus, P. aeruginosa, and E. coli, and lovage/basil EOs against B. cereus and E. coli. Combinations of parsley/lovage and parsley/basil EOs exhibited indifferent effects against all bacteria. The combination of lovage/basil EO showed indifferent effect against S. aureus, P. aeruginosa, and S. typhimurium, and the combination parsley/thyme EO against S. typhimurium. Thyme EO has the highest percentage yield and antibacterial potential from all tested formulations; its combination with parsley, lovage, and basil EOs determines a reduction of its antibacterial activity. Hence, it is recommended to be used alone as the antibacterial agent.

  20. Miniaturized bead-beating device to automate full DNA sample preparation processes for gram-positive bacteria.

    Science.gov (United States)

    Hwang, Kyu-Youn; Kwon, Sung Hong; Jung, Sun-Ok; Lim, Hee-Kyun; Jung, Won-Jong; Park, Chin-Sung; Kim, Joon-Ho; Suh, Kahp-Yang; Huh, Nam

    2011-11-07

    We have developed a miniaturized bead-beating device to automate nucleic acids extraction from Gram-positive bacteria for molecular diagnostics. The microfluidic device was fabricated by sandwiching a monolithic flexible polydimethylsiloxane (PDMS) membrane between two glass wafers (i.e., glass-PDMS-glass), which acted as an actuator for bead collision via its pneumatic vibration without additional lysis equipment. The Gram-positive bacteria, S. aureus and methicillin-resistant S. aureus, were captured on surface-modified glass beads from 1 mL of initial sample solution and in situ lyzed by bead-beating operation. Then, 10 μL or 20 μL of bacterial DNA solution was eluted and amplified successfully by real-time PCR. It was found that liquid volume fraction played a crucial role in determining the cell lysis efficiency in a confined chamber by facilitating membrane deflection and bead motion. The miniaturized bead-beating operation disrupted most of S. aureus within 3 min, which turned out to be as efficient as the conventional benchtop vortexing machine or the enzyme-based lysis technique. The effective cell concentration was significantly enhanced with the reduction of initial sample volume by 50 or 100 times. Combination of such analyte enrichment and in situ bead-beating lysis provided an excellent PCR detection sensitivity amounting to ca. 46 CFU even for the Gram-positive bacteria. The proposed bead-beating microdevice is potentially useful as a nucleic acid extraction method toward a PCR-based sample-to-answer system. This journal is © The Royal Society of Chemistry 2011

  1. Determination of the irradiation dose for the inhibition (D-10 radiation doses) of some gram negative and gram positive bacteria in peptone saline water

    International Nuclear Information System (INIS)

    Ayhan, H.; Tutluer, H.

    1994-01-01

    Determination of the irradiation dose for the inhibition of some pathogenic bacteria which cause food poisoning and spoilage were aimed. For this purpose, Salmonella typhi, Salmonella typhimurium,Salmonella enteridits,Klebsiella pneumonia, Pseudomonas fluorescence,Proteus vulgaris, Aeromonas hydrophila ,(gram-negative bacteria) and Bacillus cereus, Staphylococcus aureus strain 24,Staphylococcus aureus ATCC 6538 P,Staphylococcus epidermidis strain 115 and Clostridium perfringens A4TTK,(gram-positive bacteria) were used.Sensitivity of above mentioned bacteria to gamma rays (source Cs-137) was examined in saline with 0.1% peptone at different temperatures.Survivor plots (log.10 number of survivors versus dose) were determined by regression analysis of the data.Decimal reduction doses (D values in kGy) were calculated as the slope obtained from the regression analysis

  2. Isolation of highly active monoclonal antibodies against multiresistant gram-positive bacteria.

    Directory of Open Access Journals (Sweden)

    Friederike S Rossmann

    Full Text Available Multiresistant nosocomial pathogens often cause life-threatening infections that are sometimes untreatable with currently available antibiotics. Staphylococci and enterococci are the predominant Gram-positive species associated with hospital-acquired infections. These infections often lead to extended hospital stay and excess mortality. In this study, a panel of fully human monoclonal antibodies was isolated from a healthy individual by selection of B-cells producing antibodies with high opsonic killing against E. faecalis 12030. Variable domains (VH and VL of these immunoglobulin genes were amplified by PCR and cloned into an eukaryotic expression vector containing the constant domains of a human IgG1 molecule and the human lambda constant domain. These constructs were transfected into CHO cells and culture supernatants were collected and tested by opsonophagocytic assay against E. faecalis and S. aureus strains (including MRSA. At concentrations of 600 pg/ml, opsonic killing was between 40% and 70% against all strains tested. Monoclonal antibodies were also evaluated in a mouse sepsis model (using S. aureus LAC and E. faecium, a mouse peritonitis model (using S. aureus Newman and LAC and a rat endocarditis model (using E. faecalis 12030 and were shown to provide protection in all models at a concentration of 4 μg/kg per animal. Here we present a method to produce fully human IgG1 monoclonal antibodies that are opsonic in vitro and protective in vivo against several multiresistant Gram-positive bacteria. The monoclonal antibodies presented in this study are significantly more effective compared to another monoclonal antibody currently in clinical trials.

  3. Flow cytometric evaluation of physico-chemical impact on Gram-positive and Gram-negative bacteria

    Science.gov (United States)

    Fröhling, Antje; Schlüter, Oliver

    2015-01-01

    Since heat sensitivity of fruits and vegetables limits the application of thermal inactivation processes, new emerging inactivation technologies have to be established to fulfill the requirements of food safety without affecting the produce quality. The efficiency of inactivation treatments has to be ensured and monitored. Monitoring of inactivation effects is commonly performed using traditional cultivation methods which have the disadvantage of the time span needed to obtain results. The aim of this study was to compare the inactivation effects of peracetic acid (PAA), ozonated water (O3), and cold atmospheric pressure plasma (CAPP) on Gram-positive and Gram-negative bacteria using flow cytometric methods. E. coli cells were completely depolarized after treatment (15 s) with 0.25% PAA at 10°C, and after treatment (10 s) with 3.8 mg l−1 O3 at 12°C. The membrane potential of CAPP treated cells remained almost constant at an operating power of 20 W over a time period of 3 min, and subsequently decreased within 30 s of further treatment. Complete membrane permeabilization was observed after 10 s O3 treatment, but treatment with PAA and CAPP did not completely permeabilize the cells within 2 and 4 min, respectively. Similar results were obtained for esterase activity. O3 inactivates cellular esterase but esterase activity was detected after 4 min CAPP treatment and 2 min PAA treatment. L. innocua cells and P. carotovorum cells were also permeabilized instantaneously by O3 treatment at concentrations of 3.8 ± 1 mg l−1. However, higher membrane permeabilization of L. innocua and P. carotovorum than of E. coli was observed at CAPP treatment of 20 W. The degree of bacterial damage due to the inactivation processes is highly dependent on treatment parameters as well as on treated bacteria. Important information regarding the inactivation mechanisms can be obtained by flow cytometric measurements and this enables the definition of critical process parameters. PMID

  4. Flow cytometric evaluation of physico-chemical impact on Gram-positive and Gram-negative bacteria

    Directory of Open Access Journals (Sweden)

    Antje eFröhling

    2015-09-01

    Full Text Available Since heat sensitivity of fruits and vegetables limits the application of thermal inactivation processes, new emerging inactivation technologies have to be established to fulfil the requirements of food safety without affecting the produce quality. The efficiency of inactivation treatments has to be ensured and monitored. Monitoring of inactivation effects is commonly performed using traditional cultivation methods which have the disadvantage of the time span needed to obtain results.The aim of this study was to compare the inactivation effects of peracetic acid (PAA, ozonated water (O3 and cold atmospheric pressure plasma (CAPP on Gram-positive and Gram-negative bacteria using flow cytometric methods. E. coli cells were completely depolarized after treatment (15 s with 0.25 % PAA at 10 °C, and after treatment (10 s with 3.8 mg l-1 O3 at 12°C. The membrane potential of CAPP treated cells remained almost constant at an operating power of 20 W over a time period of 3 min, and subsequently decreased within 30 s of further treatment. Complete membrane permeabilization was observed after 10 s O3 treatment, but treatment with PAA and CAPP did not completely permeabilize the cells within 2 min and 4 min, respectively. Similar results were obtained for esterase activity. O3 inactivates cellular esterase but esterase activity was detected after 4 min CAPP treatment and 2 min PAA treatment. L. innocua cells and P. carotovorum cells were also permeabilized instantaneously by O3 treatment at concentrations of 3.8 ± 1 mg l-1. However, higher membrane permeabilization of L. innocua and P. carotovorum than of E. coli was observed at CAPP treatment of 20 W. The degree of bacterial damage due to the inactivation processes is highly dependent on treatment parameters as well as on treated bacteria. Important information regarding the inactivation mechanisms can be obtained by flow cytometric measurements and this enables the definition of critical process

  5. Evaluation of the LightCycler Staphylococcus M GRADE kits on positive blood cultures that contained gram-positive cocci in clusters.

    Science.gov (United States)

    Shrestha, Nabin K; Tuohy, Marion J; Padmanabhan, Ravindran A; Hall, Gerri S; Procop, Gary W

    2005-12-01

    We evaluated the Roche LightCycler Staphylococcus M(GRADE) kits to differentiate between Staphylococcus aureus and coagulase-negative staphylococci in blood cultures growing clusters of gram-positive cocci. Testing 100 bottles (36 containing S. aureus), the assay was 100% sensitive and 98.44% specific for S. aureus and 100% sensitive and specific for coagulase-negative staphylococci.

  6. Widespread abundance of functional bacterial amyloid in Mycolata and other Gram-positive bacteria

    DEFF Research Database (Denmark)

    Jordal, Peter Bruun; Dueholm, Morten Simonsen; Larsen, Poul

    2009-01-01

    extracellular fibrils were also produced. In three cases, FuBA was only revealed after extensive removal of extracellular material by saponification, indicating an integrated attachment within the cellular envelope. Spores from species within the genera Streptomyces, Bacillus and Nocardia were all coated...... analysis. We conclude that amyloid is widespread among Gram-positive bacteria and may in many species constitute a hitherto overlooked integral part of the spores and the cellular envelope....

  7. Isolation, one-step affinity purification, and characterization of a polyextremotolerant laccase from the halophilic bacterium Aquisalibacillus elongatus and its application in the delignification of sugar beet pulp.

    Science.gov (United States)

    Rezaei, Shahla; Shahverdi, Ahmad Reza; Faramarzi, Mohammad Ali

    2017-04-01

    The aim of the present work was to study the ability of a halophilic bacterial laccase to efficient delignification in extreme conditions. Here, a highly stable extracellular laccase showing ligninolytic activity from halophilic Aquisalibacillus elongatus is described. The laccase production was strongly influenced by NaCl and CuSO 4 and under optimal conditions reached 4.8UmL -1 . The monomeric enzyme of 75kDa was purified by a synthetic affinity column with 68.2% yield and 99.8-fold purification. The enzyme showed some valuable features viz. stability against a wide range of organic solvents, salts, metals, inhibitors, and surfactants and specificity to a wide spectrum of substrates diverse in structure and redox potential. It retained more than 50% of the original activity at 25-75°C and pH 5.0-10.0. Furthermore, the enzyme was found to be effective in the delignification of sugar beet pulp in an ionic liquid that makes it useful for industrial applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Limitations in the use of Drosophila melanogaster as a model host for gram-positive bacterial infection

    DEFF Research Database (Denmark)

    Jensen, Rikke Lind; Pedersen, K.S.; Loeschcke, V

    2007-01-01

    resistance respectively, were subjected to infection by L. monocytogenes, S. aureus and E. coli. Mortality rates were comparable with that of the Oregon R strain. Conclusions: Use of the injection method shows the limitation of D. melanogaster as a model host for gram-positive bacteria as opportunistic......Aims: To examine sensitivities of various Drosophila melanogaster strains towards human pathogenic and nonpathogenic gram-positive bacteria. Methods and Results: The D. melanogaster Oregon R strain was infected by injecting the thorax with a needle containing Escherichia coli (negative control...... with the negative control. Infection with L. innocua, B. subtilis or C. maltaromaticum also resulted in a high fly mortality, whereas Lact. plantarum and P. acidilactici resulted in a slightly increased mortality. Four additional D. melanogaster lines, three of which had been selected for heat, cold and desiccation...

  9. Hans Georg Trüper (1936–2016 and His Contributions to Halophile Research

    Directory of Open Access Journals (Sweden)

    Aharon Oren

    2016-05-01

    Full Text Available Prof. Hans Georg Trüper, one of the most important scientists in the field of halophile research, passed away on 9 March 2016 at the age of 79. I here present a brief obituary with special emphasis on Prof. Trüper’s contributions to our understanding of the halophilic prokaryotes and their adaptations to life in hypersaline environments. He has pioneered the study of the halophilic anoxygenic phototrophic sulfur bacteria of the Ectothiorhodospira—Halorhodospira group. Some of the species he and his group isolated from hypersaline and haloalkaline environments have become model organisms for the study of the mechanisms of haloadaptation: the functions of three major organic compounds – glycine betaine, ectoine, and trehalose – known to serve as “compatible solutes” in halophilic members of the Bacteria domain, were discovered during studies of these anoxygenic phototrophs. Prof. Trüper’s studies of hypersaline alkaline environments in Egypt also led to the isolation of the first known extremely halophilic archaeon (Natronomonas pharaonis. The guest editors dedicate this special volume of Life to the memory of Prof. Hans Georg Trüper.

  10. Improvement of halophilic cellulase production from locally isolated fungal strain.

    Science.gov (United States)

    Gunny, Ahmad Anas Nagoor; Arbain, Dachyar; Jamal, Parveen; Gumba, Rizo Edwin

    2015-07-01

    Halophilic cellulases from the newly isolated fungus, Aspergillus terreus UniMAP AA-6 were found to be useful for in situ saccharification of ionic liquids treated lignocelluloses. Efforts have been taken to improve the enzyme production through statistical optimization approach namely Plackett-Burman design and the Face Centered Central Composite Design (FCCCD). Plackett-Burman experimental design was used to screen the medium components and process conditions. It was found that carboxymethylcellulose (CMC), FeSO4·7H2O, NaCl, MgSO4·7H2O, peptone, agitation speed and inoculum size significantly influence the production of halophilic cellulase. On the other hand, KH2PO4, KOH, yeast extract and temperature had a negative effect on enzyme production. Further optimization through FCCCD revealed that the optimization approach improved halophilic cellulase production from 0.029 U/ml to 0.0625 U/ml, which was approximately 2.2-times greater than before optimization.

  11. Characterization of an Hfq dependent antisense sRNA in the Gram-positive human pathogen Listeria monocytogenes

    DEFF Research Database (Denmark)

    Nielsen, Jesper Sejrup; Lei Kristensen, Lisbeth; Hanghøj Chrisitansen, Mie

    between sRNA and target mRNA rely on the RNA chaperone Hfq. Hfq is a ubiquitous protein found in almost all genres of bacterial life. However, so far its role as an RNA chaperone has only been described in Gram-negative species such as Escherichia coli and Salmonella (Vogel, J. 2009). We previously...... identified several Hfq-binding sRNAs in the Gram-positive human pathogen L. monocytogenes (Christiansen et al 2006). Through bioinformatics, we have identified a number of candidate targets for one of these sRNAs (LhrA). Here, we present the characterization of one of these targets. Our results suggest...

  12. A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris*

    Science.gov (United States)

    Reardon-Robinson, Melissa E.; Osipiuk, Jerzy; Chang, Chungyu; Wu, Chenggang; Jooya, Neda; Joachimiak, Andrzej; Das, Asis; Ton-That, Hung

    2015-01-01

    Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria. PMID:26170452

  13. A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris.

    Science.gov (United States)

    Reardon-Robinson, Melissa E; Osipiuk, Jerzy; Chang, Chungyu; Wu, Chenggang; Jooya, Neda; Joachimiak, Andrzej; Das, Asis; Ton-That, Hung

    2015-08-28

    Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Características morfo-tintoriales en el ciclo celular de Acinetobacter baumannii por los métodos de Gram y 4’, 6-diamidino-2’-fenilindol, dihidrocloruro | Morphological and staining characteristics in cell cycle of Acinetobacter baumannii by the methods of Gram and 4´, 6-diamidino-2´-phenylindole, dihydrochloride

    Directory of Open Access Journals (Sweden)

    Evelin Flores Hernández

    2017-11-01

    Full Text Available Several studies have reported variations in bacterial staining by Gram, which are associated with the content of nucleic acids in the bacterial cell cycle. In order to give continuity to the microscopical studies pertaining to the bacterial cell cycle, the morphological and staining characteristics were evaluated by Gram and 4', 6-diamidino-2'-phenylindole, dihydrochloride (DAPI in the cell cycle of Acinetobacter baumannii. From the synchronic cultures of 4 strains of A. baumannii, the cell cycle was studied incubating them in aerobiosis at 30ºC, taking aliquots every 5 min for 2 h. In turn, the respective extensions were made and stained with Gram and DAPI for their posterior microscopical study. In the statistical analysis Fischer's test was used to associate morphological and the staining characteristics by Gram and DAPI. In 74% of cycle times, the cocoid form predominated and 67% in the negative Gram staining. When determining the mean and standard deviation of bacterial morphological values, it was observed that between 15 and 55 min the bacterium initiates a new cell cycle, decreasing its diameter and length. There was a statistically significant association (p < 0.05 between the lax and compact appearance of the material with the light and intense fluorescent, respectively; likewise, between the strong Gram positive character and the intense fluorescence. It is concluded that in the Gram positive reaction, the DNA is possibly involved and that the purple material of compact and lax aspect observed by Gram staining in the bacterial cytoplasm correspond to the nucleoid and the morphological changes obey to the cellular growth process. These findings contribute to explain the mechanism of Gram staining, as well as its variability and the pleomorphism observed in this bacterial genus.

  15. New and improved? A review of novel antibiotics for Gram-positive bacteria.

    Science.gov (United States)

    Abbas, M; Paul, M; Huttner, A

    2017-10-01

    The number of antibiotics in the pipeline targeting Gram-positive pathogens has increased in recent years. This narrative review aims to provide a summary of existing evidence on efficacy, microbiological spectrum and safety of novel systemic antibiotics that have either recently been licensed or completed phase III trials, and possess activity predominantly against Gram-positive organisms. A review of the published literature via the MEDLINE database was performed. In addition, ongoing trials were identified through a search of the clinical trial registration platform clinicaltrials.gov, and when necessary, pharmaceutical companies responsible for the development of the drug were contacted for further information. Data on development, microbiological spectrum, pharmacokinetic/pharmacodynamic properties, clinical efficacy, safety and cost are presented for the new cephalosporins ceftaroline and ceftobiprole; the lipoglycopeptides dalbavancin, oritavancin and telavancin; the fluoroquinolones delafloxacin, nemonoxacin and zabofloxacin; the dihydrofolate-reductase inhibitor iclaprim; the pleuromutilin lefamulin; and the tetracycline omadacycline. Although promising, these new antibiotics have so far been tested in non-severe infections whose treatment is generally uncomplicated and whose aetiologies were not predominantly multidrug-resistant pathogens. None of the new antibiotics have shown superiority to standard care, and none have been investigated for patient-relevant outcomes. Safety and pharmacokinetic data continue to be lacking. How these new drugs are to be integrated into the current armamentarium remains to be established. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  16. Antibacterial properties of biosurfactants against selected Gram-positive and -negative bacteria.

    Science.gov (United States)

    Díaz De Rienzo, Mayri A; Stevenson, Paul; Marchant, Roger; Banat, Ibrahim M

    2016-01-01

    The antibacterial properties and ability to disrupt biofilms of biosurfactants (rhamnolipids, sophorolipids) and sodium dodecyl sulphate (SDS) in the presence and absence of selected organic acids were investigated. Pseudomonas aeruginosa PAO1 was inhibited by sophorolipids and SDS at concentrations >5% v/v, and the growth of Escherichia coli NCTC 10418 was also inhibited by sophorolipids and SDS at concentrations >5% and 0.1% v/v, respectively. Bacillus subtilis NCTC 10400 was inhibited by rhamnolipids, sophorolipids and SDS at concentrations >0.5% v/v of all three; the same effect was observed with Staphylococcus aureus ATCC 9144. The ability to attach to surfaces and biofilm formation of P. aeruginosa PAO1, E. coli NCTC 10418 and B. subtilis NCTC 10400 was inhibited by sophorolipids (1% v/v) in the presence of caprylic acid (0.8% v/v). In the case of S. aureus ATCC 9144, the best results were obtained using caprylic acid on its own. It was concluded that sophorolipids are promising compounds for the inhibition/disruption of biofilms formed by Gram-positive and Gram-negative microorganisms and this activity can be enhanced by the presence of booster compounds such as caprylic acid. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Engineering a predatory bacterium as a proficient killer agent for intracellular bio-products recovery

    DEFF Research Database (Denmark)

    Martinez, Virginia; Herencias, Cristina; Jurkevitch, Edouard

    2016-01-01

    This work examines the potential of the predatory bacterium Bdellovibrio bacteriovorus HD100, an obligate predator of other Gram-negative bacteria, as an external cell-lytic agent for recovering valuable intracellular bio-products produced by prey cultures. The bio-product targets to be recovered......% of that accumulated by the prey bacteria, even at high biomass concentrations. This innovative downstream process highlights how B. bacteriovorus can be used as a novel, biological lytic agent for the inexpensive, industrial scale recovery of intracellular products from different Gram-negative prey cultures....

  18. A Flexible Binding Site Architecture Provides New Insights into CcpA Global Regulation in Gram-Positive Bacteria.

    Science.gov (United States)

    Yang, Yunpeng; Zhang, Lu; Huang, He; Yang, Chen; Yang, Sheng; Gu, Yang; Jiang, Weihong

    2017-01-24

    Catabolite control protein A (CcpA) is the master regulator in Gram-positive bacteria that mediates carbon catabolite repression (CCR) and carbon catabolite activation (CCA), two fundamental regulatory mechanisms that enable competitive advantages in carbon catabolism. It is generally regarded that CcpA exerts its regulatory role by binding to a typical 14- to 16-nucleotide (nt) consensus site that is called a catabolite response element (cre) within the target regions. However, here we report a previously unknown noncanonical flexible architecture of the CcpA-binding site in solventogenic clostridia, providing new mechanistic insights into catabolite regulation. This novel CcpA-binding site, named cre var , has a unique architecture that consists of two inverted repeats and an intervening spacer, all of which are variable in nucleotide composition and length, except for a 6-bp core palindromic sequence (TGTAAA/TTTACA). It was found that the length of the intervening spacer of cre var can affect CcpA binding affinity, and moreover, the core palindromic sequence of cre var is the key structure for regulation. Such a variable architecture of cre var shows potential importance for CcpA's diverse and fine regulation. A total of 103 potential cre var sites were discovered in solventogenic Clostridium acetobutylicum, of which 42 sites were picked out for electrophoretic mobility shift assays (EMSAs), and 30 sites were confirmed to be bound by CcpA. These 30 cre var sites are associated with 27 genes involved in many important pathways. Also of significance, the cre var sites are found to be widespread and function in a great number of taxonomically different Gram-positive bacteria, including pathogens, suggesting their global role in Gram-positive bacteria. In Gram-positive bacteria, the global regulator CcpA controls a large number of important physiological and metabolic processes. Although a typical consensus CcpA-binding site, cre, has been identified, it remains

  19. In vitro ciprofloxacin resistance patterns of gram positive bacteria isolated from clinical specimens in a teaching hospital in Saudi Arabia

    International Nuclear Information System (INIS)

    Akhtar, N.; Alzahrani, A.; Obeid, O.El-Treify; Dassal, D.

    2009-01-01

    Over the last few decades the ever-increasing level of bacterial resistance to antimicrobials has been a cause of worldwide concern. Fluoroquinolones, particularly ciprofloxacin has been used indiscriminately for both gram-positive and gram-negative bacterial infections. The increased use of ciprofloxacin has led to a progressive loss of bacterial susceptibility to this antibiotic. Therefore it is necessary to have update knowledge of resistance pattern of bacteria to this antibiotic so that alternate appropriate antibiotics can be used for ciprofloxacin-resistant bacterial infections. Objective: To evaluate the trends of ciprofloxacin resistance pattern in commonly isolated gram positive bacteria over time in a Saudi Arabian teaching hospital. Methods: A retrospective analysis was carried out for ciprofloxacin susceptibility patterns of 5534 isolates of gram-positive bacteria isolated from clinical specimens submitted to microbiology laboratories at King Fahd Hospital of the University (KFHU), Al-Khobar, Saudi Arabia during the period from January 2002 to August 2005. Results: Increase in ciprofloxacin resistance rates with some fluctuations, among these isolates, were observed. For Staphylococcus aureus, it varied from 4.62, 1.83, 7.01 and 3.98%, methicillin resistant Staphylococcus aureus (MRSA) 97.92, 97.75, 87.01 and 88.26%, Streptococcus pyogenes 5.35, 4.47, 14.44 and 3.53% during the years 2002, 2003, 2004 and 2005 respectively. Cirprofloxacin resistance during the years 2002, 2004 and 2005 for other isolates was as follows: Streptococcus pneumoniae, 30.23, 23.02 and 26.47%; enterococcus group D, 43.05, 20.68 and 57.03% and non-enterococcus group D, 62.96, 76.92 and 87.50% respectively. Conclusion: Ciprofloxacin resistance in gram positive bacterial clinical isolates particularly Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA) enterococcus group D, and non-enterococcus group D, has greatly increased and ciprofloxacin no more remains

  20. Gram-negative diabetic foot osteomyelitis: risk factors and clinical presentation.

    Science.gov (United States)

    Aragón-Sánchez, Javier; Lipsky, Benjamin A; Lázaro-Martínez, Jose L

    2013-03-01

    Osteomyelitis frequently complicates infections in the feet of patients with diabetes. Gram-positive cocci, especially Staphylococcus aureus, are the most commonly isolated pathogens, but gram-negative bacteria also cause some cases of diabetic foot osteomyelitis (DFO). These gram-negatives require different antibiotic regimens than those commonly directed at gram-positives. There are, however, few data on factors related to their presence and how they influence the clinical picture. We conducted a retrospective study to determine the variables associated with the isolation of gram-negative bacteria from bone samples in cases of DFO and the clinical presentation of these infections. Among 341 cases of DFO, 150 had a gram-negative isolate (alone or combined with a gram-positive isolate) comprising 44.0% of all patients and 50.8% of those with a positive bone culture. Compared with gram-positive infections, wounds with gram-negative organisms more often had a fetid odor, necrotic tissue, signs of soft tissue infection accompanying osteomyelitis, and clinically severe infection. By multivariate analysis, the predictive variables related to an increased likelihood of isolating gram-negatives from bone samples were glycated hemoglobin gram-negatives had a statistically significantly higher prevalence of leukocytosis and higher white blood cell counts than those without gram-negatives. In conclusion, gram-negative organisms were isolated in nearly half of our cases of DFO and were associated with more severe infections, higher white blood cell counts, lower glycated hemoglobin levels, and wounds of traumatic etiology.

  1. Brazilian experience in EU-CORE: daptomycin registry and treatment of serious Gram-positive infections

    Directory of Open Access Journals (Sweden)

    Artur Timerman

    Full Text Available OBJECTIVES: To collect data about non-controlled prescribing use of daptomycin and its impact among Brazilian patients with serious Gram positive bacterial infection, as well as the efficacy and safety outcomes. MATERIALS AND METHODS: This is a multi-center, retrospective, non-interventional registry (August 01, 2009 to June 30, 2011 to collect data on 120 patients (44 patients in the first year and 76 patients in the second year who had received at least one dose of commercial daptomycin in Brazil for the treatment of serious Gram-positive bacterial infection. RESULTS: Right-sided endocarditis (15.8%, complicated skin and soft tissue infections (cSSTIwound (15.0% and bacteremia-catheter-related (14.2% were the most frequent primary infections; lung (21.7% was the most common site for infection. Daptomycin was used empirically in 76 (63.3% patients, and methicillin-resistant Staphylococcus aureus (MRSA was the most common suspected pathogen (86.1%. 82.5% of the cultures were obtained prior to or shortly after initiation of daptomycin therapy. Staphylococcus spp. - coagulase negative, MRSA, and methicillin-susceptible S. aureus were the most frequently identified pathogens (23.8%, 23.8% and 12.5%, respectively. The most common daptomycin dose administered for bacteremia and cSSTI was 6 mg/kg (30.6% and 4 mg/kg (51.7%, respectively. The median duration of inpatient daptomycin therapy was 14 days. Most patients (57.1% did not receive daptomycin while in intensive care unit. Carbapenem (22.5% was the most commonly used antibiotic concomitantly. The patients showed clinical improvement after two days (median following the start of daptomycin therapy. The clinical success rate was 80.8% and the overall rate of treatment failure was 10.8%. The main reasons for daptomycin discontinuation were successful end of therapy (75.8%, switched therapy (11.7%, and treatment failure (4.2%. Daptomycin demonstrated a favorable safety and tolerability profile

  2. Veillonella, Firmicutes: Microbes disguised as Gram negatives

    DEFF Research Database (Denmark)

    Vesth, Tammi Camilla; Ozen, Asli; Andersen, Sandra Christine

    2013-01-01

    Negativicutes, including the genus Veillonella, stain Gram negative. Veillonella are among the most abundant organisms of the oral and intestinal microflora of animals and humans, in spite of being strict anaerobes. In this work, the genomes of 24 Negativicutes, including eight Veillonella spp., are compared......, with the exception of a shared LPS biosynthesis pathway. The clade within the class Negativicutes to which the genus Veillonella belongs exhibits unique properties, most of which are in common with Gram-positives and some with Gram negatives. They are only distantly related to Clostridia, but are even less closely...... related to Gram-negative species. Though the Negativicutes stain Gram-negative and possess two membranes, the genome and proteome analysis presented here confirm their place within the (mainly) Gram positive phylum of the Firmicutes. Further studies are required to unveil the evolutionary history...

  3. Two investigational glycylcyclines, DMG-DMDOT and DMG-MINO. Antimicrobial activity studies against gram-positive species.

    Science.gov (United States)

    Johnson, D M; Jones, R N

    1996-01-01

    DMG-DMDOT (CL-331,002 OR CL-331,928) and DMG-MINO (CL-329,998 or CL-344,677) are two new semisynthetic tetracyclines called glycylcyclines, with a broad spectrum of activity and includes Enterobacteriaceae, Gram-positive cocci, JK diphtheroids, and Bacillus cereus. Potent activity was demonstrated against all Streptococcus spp. strains [minimum inhibitory concentrations] (MIC90S) 0.06-0.25 micrograms/ml) and staphylococci (oxacillin susceptible ans resistant; MIC90S 0.12-2 micrograms/ml). Both glycylcyclines (MIC90, 0.06 micrograms/ml) were more potent than minocycline (MIC90 8 micrograms/ml) against Enterococcus faecium, many of which were vancomycin resistant (116 strains). Organisms with minocycline MICs at > or = 8 micrograms/ml (Staphylococcus aureus, enterococci, beta-hemolytic streptococci, and pneumococci) had glycylcycline MIC results ranging from 0.06 to 0.5 micrograms/ml (e.g., apparent use against existing tetracycline-resistance phenotypes). Drugs in this class appear promising for therapy of infections caused by Gram-positive species now testing resistant to contemporary antimicrobial agents, and further development of compounds in this class is encouraged.

  4. Egibacter rhizosphaerae gen. nov., sp. nov., an obligately halophilic, facultatively alkaliphilic actinobacterium and proposal of Egibaceraceae fam. nov. and Egibacterales ord. nov.

    Science.gov (United States)

    Zhang, Yong-Guang; Wang, Hong-Fei; Yang, Ling-Ling; Zhou, Xing-Kui; Zhi, Xiao-Yang; Duan, Yan-Qing; Xiao, Min; Zhang, Yuan-Ming; Li, Wen-Jun

    2016-01-01

    A novel obligately halophilic, facultatively alkaliphilic actinobacterium, designated EGI 80759T, was isolated from the rhizosphere of Tamarix hispida Willd, Karamay, Xinjiang province, north-west China. Cells of strain EGI 80759T were Gram-stain-positive, non-motile and non-endospore-forming rods. Strain EGI 80759T showed obligately halophilic growth with a tolerance to 8-25 % (w/v) NaCl (optimum growth at 10-12 %, w/v) and facultatively alkaliphilic growth within the pH range 7.0-11.0 (optimum growth at pH 9.0-10.0). Cell-wall hydrolysates of the isolate contained meso-diaminopimelic acid (peptidoglycan type A1γ), with glucose, glucosamine, ribose and mannose as the major sugars. The major fatty acids identified were 10-methyl-C17 : 0, C17 : 1ω8c and C17 : 0. The predominant menaquinone was MK-9(H4). The G+C content of the genomic DNA was 72.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain EGI 80759T clustered with members of the class Nitriliruptoria and showed highest 16S rRNA gene sequence similarities with Euzebya tangerina F10T (90.3 %) and Nitriliruptor alkaliphilus ANL-iso2T (88.1 %). On the basis of the data obtained from phenotypic and chemotaxonomic studies and the phylogenetic analysis, the isolate is proposed to be a representative of a novel genus and a novel species, Egibacter rhizosphaerae gen. nov., sp. nov., of a proposed novel family, Egibacteraceae fam. nov., and order, Egibacterales ord. nov., within the class Nitriliruptoria. The type strain of the type species, Egibacter rhizosphaerae, is EGI 80759T ( = CGMCC 1.14997T = KCTC 39588T).

  5. Subsurface Halophilic Microbial Communities in the Hyperarid Core of the Atacama Desert: An Analog for Possible Subsurface Life in Regolith on Mars

    Science.gov (United States)

    Oren, A.; Warren-Rhodes, K.; Rainey, F. T.; Ewing, S.; McKay, C. P.

    2003-12-01

    The Atacama Desert in its driest portion provides an interesting analog for possible past or present life in the Martian regolith. In the hyperarid core of the Atacama, surface soils are virtually abiotic, with no plants and "near sterile" concentrations of heterotrophic bacteria (i.e., exceedingly low densities of approximately 100 colony forming units per gram soil). The dearth of microbial life at the surface is likely maintained through extremely low water availability, low organic content and the highly oxidizing nature of the soil. In marked contrast to the surface, however, extremely halophilic microorganisms exist in salt layers 1.2-1.5m below the surface. Mineralogical analyses indicate the layers are predominantly halite (70% NaCl) but also contain sodium nitrate (5% NaNO3). Culturing and polar lipid analyses suggest the halophiles are archaeal Halobacterium-like motile rods. Microclimate monitoring at 1m indicates a soil relative humidity of 20% which is stable year-round even during decadal rain events such as that experienced in July 2002. This suggests the layers are isolated from even significant moisture influxes at the surface. Although further research is necessary, important parallels exist between this Earthly desert analog and the possible existence and detection of subsurface life on Mars despite harsh abiotic conditions at the surface.

  6. Inactivation dynamics of 222 nm krypton-chlorine excilamp irradiation on Gram-positive and Gram-negative foodborne pathogenic bacteria.

    Science.gov (United States)

    Kang, Jun-Won; Kim, Sang-Soon; Kang, Dong-Hyun

    2018-07-01

    The object of this study was to elucidate the bactericidal mechanism of a 222 nm Krypton Chlorine (KrCl) excilamp compared with that of a 254 nm Low Pressure mercury (LP Hg) lamp. The KrCl excilamp had higher bactericidal capacity against Gram-positive pathogenic bacteria (Staphylococcus aureus and L. monocytogenes) and Gram-negative pathogenic bacteria (S. Typhimurium and E. coli O157:H7) than did the LP Hg lamp when cell suspensions in PBS were irradiated with each type of UV lamp. It was found out that the KrCl excilamp induced cell membrane damage as a form of depolarization. From the study of respiratory chain dehydrogenase activity and the lipid peroxidation assay, it was revealed that cell membrane damage was attributed to inactivation of enzymes related to generation of membrane potential and occurrence of lipid peroxidation. Direct absorption of UV radiation which led to photoreaction through formation of an excited state was one of the causes inducing cell damage. Additionally, generation of ROS and thus occurrence of secondary damage can be another cause. The LP Hg lamp only induced damage to DNA but not to other components such as lipids or proteins. This difference was derived from differences of UV radiation absorption by cellular materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Ornithinibacillus salinisoli sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil.

    Science.gov (United States)

    Gan, Longzhan; Zhang, Heming; Long, Xiufeng; Tian, Jiewei; Wang, Zhikuan; Zhang, Yuqin; Dai, Yumei; Tian, Yongqiang

    2018-03-01

    A taxonomic study was performed on strain LCB256 T , which was isolated from a saline-alkali soil sample taken from northwestern China. Cells of strain LCB256 T were Gram-stain-positive, aerobic, rod-shaped and grew at 3-17 % (w/v) NaCl (optimum 10-15 %), 10-52 °C (optimum 25-30 °C) and pH 7.0-9.0 (optimum 8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LCB256 T was most closely related to the two genera of Ornithinibacillus and Oceanobacillus, showing highest sequence similarity to Oceanobacillus limi KCTC 13823 T (97.8 %) and Ornithinibacillus bavariensis WSBC 24001 T (97.2 %). The peptidoglycan amino acid type was found to be A4β and the major respiratory quinone was determined to be MK-7. The polar lipid profile of strain LCB256 T contained diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and two unidentified aminolipids. The dominant cellular fatty acids were anteiso-C15 : 0 and iso-C15 : 0. The G+C content of genomic DNA was 39.3 mol%. DNA-DNA relatedness values between strain LCB256 T and Ornithinibacillus halophilus KCTC 13822 T and Oceanobacillus limi KCTC 13823 T were 46.2 and 34.8 %, respectively. Based on this polyphasic taxonomic study, a novel species of the genus Ornithinibacillus, Ornithinibacillussalinisoli sp. nov. is proposed. The type strain is LCB256 T (=CGMCC 1.15809 T =KCTC 33862 T ).

  8. Response surface method optimization of ectoine fermentation medium with moderate halophilic bacteria Halomonas sp. H02

    Science.gov (United States)

    Li, T. T.; Qu, A.; Yuan, X. N.; Tan, F. X.; Li, X. W.; Wang, T.; Zhang, L. H.

    2017-07-01

    Moderate halophilic bacteria are of halophilic bacteria whose suitable growth of NaCl is 5-10%. When the moderate halophilic bacteria response to high osmotic stress, the intracellular will synthesize small organic molecule compatible solutes. Ectoine, which is the major synthetic osmotic compatible solutes for moderate halophilic bacteria, can help microbial enzymes, nucleic acids and the whole cell resist to hypertonic, high temperature, freezing and other inverse environment. In order to increase the Ectoine production of Moderate halophilic bacteria Halomonas sp. H02, the Ectoine fermentation medium component was optimized by Plackett-Burman (PB) and Response Surface Methodology (RSM) based on the principle of non-complete equilibrium The results of PB experiments showed that the three main influencing factors of Moderate halophilic bacteria Halomonas sp. H02 synthesis Ectoine culture medium were C5H8NNaO4 concentration, NaCl concentration and initial pH. According to the center point of the steepest climbing experiment, the central combination design experiment was used to show that the model is consistent with the actual situation. The optimum combination of three influencing factors were C5H8NNaO4 41 g/L, NaCl 87.2 g/L and initial pH 5.9, and the predicted amount of Ectoine was 1835.8 mg/L, increased by 41.6%.

  9. Characterization of the proteasome from the extremely halophilic archaeon Haloarcula marismortui

    Directory of Open Access Journals (Sweden)

    B. Franzetti

    2002-01-01

    Full Text Available A 20S proteasome, comprising two subunits α and β, was purified from the extreme halophilic archaeon Haloarcula marismortui, which grows only in saturated salt conditions. The three-dimensional reconstruction of the H. marismortui proteasome (Hm proteasome, obtained from negatively stained electron micrographs, is virtually identical to the structure of a thermophilic proteasome filtered to the same resolution. The stability of the Hm proteasome was found to be less salt-dependent than that of other halophilic enzymes previously described. The proteolytic activity of the Hm proteasome was investigated using the malate dehydrogenase from H. marismortui (HmMalDH as a model substrate. The HmMalDH denatures when the salt concentration is decreased below 2 M. Under these conditions, the proteasome efficiently cleaves HmMalDH during its denaturation process, but the fully denatured HmMalDH is poorly degraded. These in vitro experiments show that, at low salt concentrations, the 20S proteasome from halophilic archaea eliminates a misfolded protein.

  10. Environmental gram-positive mastitis treatment: in vitro sensitivity and bacteriologic cure.

    Science.gov (United States)

    Cattell, M B; Dinsmore, R P; Belschner, A P; Carmen, J; Goodell, G

    2001-09-01

    A clinical trial was conducted in a large dairy herd to determine the efficacy of intramammary pirlimycin hydrochloride administration during lactation for bacteriologic clearance of gram-positive environmental clinical and subclinical mastitis infections. Quarters infected with environmental streptococci that received pirlimycin therapy (13/28) were 1.8 times more likely to resolve infection than untreated quarters (5/14). The small numbers of quarters infected with coagulase-negative staphylococci resulted in inadequate power to assess treatment differences in cure rate. Although the association was not statistically significant, quarters from cows with sensitive environmental streptococci isolates from composite samples (8/13) resolved infection with treatment at approximately twice the rate of treated quarters with resistant isolates (3/10).

  11. Simultaneous fluorescent gram staining and activity assessment of activated sludge bacteria.

    Science.gov (United States)

    Forster, Scott; Snape, Jason R; Lappin-Scott, Hilary M; Porter, Jonathan

    2002-10-01

    Wastewater treatment is one of the most important commercial biotechnological processes, and yet the component bacterial populations and their associated metabolic activities are poorly understood. The novel fluorescent dye hexidium iodide allows assessment of Gram status by differential absorption through bacterial cell walls. Differentiation between gram-positive and gram-negative wastewater bacteria was achieved after flow cytometric analysis. This study shows that the relative proportions of gram-positive and gram-negative bacterial cells identified by traditional microscopy and hexidium iodide staining were not significantly different. Dual staining of cells for Gram status and activity proved effective in analyzing mixtures of cultured bacteria and wastewater populations. Levels of highly active organisms at two wastewater treatment plants, both gram positive and gram negative, ranged from 1.5% in activated sludge flocs to 16% in the activated sludge fluid. Gram-positive organisms comprised Gram status and activity within activated sludge samples over a 4-day period showed significant differences over time. This method provides a rapid, quantitative measure of Gram status linked with in situ activity within wastewater systems.

  12. Techniques for controlling variability in gram staining of obligate anaerobes.

    Science.gov (United States)

    Johnson, M J; Thatcher, E; Cox, M E

    1995-01-01

    Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes. PMID:7538512

  13. Phosphate enhances levan production in the endophytic bacterium Gluconacetobacter diazotrophicus Pal5

    Science.gov (United States)

    Idogawa, Nao; Amamoto, Ryuta; Murata, Kousaku; Kawai, Shigeyuki

    2014-01-01

    Gluconacetobacter diazotrophicus is a gram-negative and endophytic nitrogen-fixing bacterium that has several beneficial effects in host plants; thus, utilization of this bacterium as a biofertilizer in agriculture may be possible. G. diazotrophicus synthesizes levan, a D-fructofuranosyl polymer with β-(2→6) linkages, as an exopolysaccharide and the synthesized levan improves the stress tolerance of the bacterium. In this study, we found that phosphate enhances levan production by G. diazotrophicus Pal5, a wild type strain that showed a stronger mucous phenotype on solid medium containing 28 mM phosphate than on solid medium containing 7 mM phosphate. A G. diazotrophicus Pal5 levansucrase disruptant showed only a weak mucous phenotype regardless of the phosphate concentration, indicating that the mucous phenotype observed on 28 mM phosphate medium was caused by levan. To our knowledge, this is the first report of the effect of a high concentration of phosphate on exopolysaccharide production. PMID:24717418

  14. Evaluation of the Verigene Gram-positive blood culture nucleic acid test for rapid detection of bacteria and resistance determinants.

    Science.gov (United States)

    Wojewoda, Christina M; Sercia, Linda; Navas, Maria; Tuohy, Marion; Wilson, Deborah; Hall, Geraldine S; Procop, Gary W; Richter, Sandra S

    2013-07-01

    Rapid identification of pathogens from blood cultures can decrease lengths of stay and improve patient outcomes. We evaluated the accuracy of the Verigene Gram-positive blood culture (BC-GP) nucleic acid test for investigational use only (Nanosphere, Inc., Northbrook, IL) for the identification of Gram-positive bacteria from blood cultures. The detection of resistance genes (mecA in Staphylococcus aureus and Staphylococcus epidermidis and vanA or vanB in Enterococcus faecium and Enterococcus faecalis) by the BC-GP assay also was assessed. A total of 186 positive blood cultures (in BacT/Alert FA bottles) with Gram-positive cocci observed with Gram staining were analyzed using the BC-GP assay. The BC-GP results were compared with the identification and susceptibility profiles obtained with routine methods in the clinical laboratory. Discordant results were arbitrated with additional biochemical, cefoxitin disk, and repeat BC-GP testing. The initial BC-GP organism identification was concordant with routine method results for 94.6% of the blood cultures. Only 40% of the Streptococcus pneumoniae identifications were correct. The detection of the mecA gene for 69 blood cultures with only S. aureus or S. epidermidis was concordant with susceptibility testing results. For 3 of 6 cultures with multiple Staphylococcus spp., mecA detection was reported but was correlated with oxacillin resistance in a species other than S. aureus or S. epidermidis. The detection of vanA agreed with susceptibility testing results for 45 of 46 cultures with E. faecalis or E. faecium. Comparison of the mean times to results for each organism group showed that BC-GP results were available 31 to 42 h earlier than phenotypic identifications and 41 to 50 h earlier than susceptibility results.

  15. Intestinimonas butyriciproducens gen. nov., sp. nov., a novel butyrate-producing bacterium from the mouse intestine

    NARCIS (Netherlands)

    Kläring, K.; Hanske, L.; Bui, T.P.N.; Charrier, C.; Blaut, M.; Haller, D.; Plugge, C.M.; Clavel, T.

    2013-01-01

    Whilst creating a bacterial collection of strains from the mouse intestine, we isolated a Gram-negative, spore-forming, non-motile and strictly anaerobic rod-shaped bacterium from the caecal content of a TNFdeltaARE mouse. The isolate, referred to as strain SRB-521-5-IT, was originally cultured on a

  16. In Vitro Antioxidant, Antihemolytic, and Anticancer Activity of the Carotenoids from Halophilic Archaea.

    Science.gov (United States)

    Hou, Jing; Cui, Heng-Lin

    2018-03-01

    Halophilic archaea represent a promising natural source of carotenoids. However, little information is available about the biological effects of carotenoids from halophilic archaea. In this study, the carotenoids produced by seven halophilic archaeal strains Halogeometricum rufum, Halogeometricum limi, Haladaptatus litoreus, Haloplanus vescus, Halopelagius inordinatus, Halogranum rubrum, and Haloferax volcanii were identified by ultraviolet/visible spectroscopy, thin-layer chromatography, and high-performance liquid chromatography-tandem mass spectrometry. The C 50 carotenoids bacterioruberin and its derivatives monoanhydrobacterioruberin and bisanhydrobacterioruberin were found to be the predominant carotenoids. The antioxidant capacities of the carotenoids from these strains were significantly higher than β-carotene as determined by 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. The antihemolytic activities of these carotenoid extracts against H 2 O 2 -induced hemolysis in mouse erythrocytes were 3.9-6.3 times higher than β-carotene. A dose-dependent in vitro antiproliferative activity against HepG2 cells was observed for the extract from Hgm. limi, while that from Hpn. vescus exhibited a relatively high activity in a dose-independent manner. These results suggested that halophilic archaea could be considered as an alternative source of natural carotenoids with high antioxidant, antihemolytic, and anticancer activity.

  17. Gram-positive bacteria of marine origin: a numerical taxonomic study on Mediterranean isolates.

    Science.gov (United States)

    Ortigosa, M; Garay, E; Pujalte, M J

    1997-12-01

    A numerical taxonomic study was performed on 65 Gram-positive wild strains of heterotrophic, aerobic, marine bacteria, and 9 reference strains. The isolates were obtained from oysters and seawater sampled monthly over one year, by direct plating on Marine Agar. The strains were characterized by 96 morphological, biochemical, physiological and nutritional tests. Clustering yielded 13 phena at 0.62 similarity level (Sl coefficient). Only one of the seven phena containing wild isolates could be identified (Bacillus marinus). A pronounced salt requirement was found in most isolates.

  18. High positive predictive value of Gram stain on catheter-drawn blood samples for the diagnosis of catheter-related bloodstream infection in intensive care neonates.

    Science.gov (United States)

    Deleers, M; Dodémont, M; Van Overmeire, B; Hennequin, Y; Vermeylen, D; Roisin, S; Denis, O

    2016-04-01

    Catheter-related bloodstream infections (CRBSIs) remain a leading cause of healthcare-associated infections in preterm infants. Rapid and accurate methods for the diagnosis of CRBSIs are needed in order to implement timely and appropriate treatment. A retrospective study was conducted during a 7-year period (2005-2012) in the neonatal intensive care unit of the University Hospital Erasme to assess the value of Gram stain on catheter-drawn blood samples (CDBS) to predict CRBSIs. Both peripheral samples and CDBS were obtained from neonates with clinically suspected CRBSI. Gram stain, automated culture and quantitative cultures on blood agar plates were performed for each sample. The paired quantitative blood culture was used as the standard to define CRBSI. Out of 397 episodes of suspected CRBSIs, 35 were confirmed by a positive ratio of quantitative culture (>5) or a colony count of CDBS culture >100 colony-forming units (CFU)/mL. All but two of the 30 patients who had a CDBS with a positive Gram stain were confirmed as having a CRBSI. Seven patients who had a CDBS with a negative Gram stain were diagnosed as CRBSI. The sensitivity, specificity, positive predictive value and negative predictive value of Gram stain on CDBS were 80, 99.4, 93.3 and 98.1 %, respectively. Gram staining on CDBS is a viable method for rapidly (<1 h) detecting CRBSI without catheter withdrawal.

  19. Draft Genome Sequence of Pontibacter sp. nov. BAB1700, a Halotolerant, Industrially Important Bacterium

    Science.gov (United States)

    Joshi, M. N.; Sharma, A. C.; Pandya, R. V.; Patel, R. P.; Saiyed, Z. M.; Saxena, A. K.

    2012-01-01

    Pontibacter sp. nov. BAB1700 is a halotolerant, Gram-negative, rod-shaped, pink-pigmented, menaquinone-7-producing bacterium isolated from sediments of a drilling well. The draft genome sequence of the strain, consisting of one chromosome of 4.5 Mb, revealed vital gene clusters involved in vitamin biosynthesis and resistance against various metals and antibiotics. PMID:23105068

  20. Arcobacter halophilus sp nov., the first obligate halophile in the genus Arcobacter

    DEFF Research Database (Denmark)

    Donachie, S.P.; Bowman, J.P.; On, Stephen L.W.

    2005-01-01

    . Most notably, LA31B(T) was found to be an obligate halophile, a hitherto undescribed feature among recognized Arcobacter species. These data indicate that LA31B(T) should be considered to represent a novel species in the genus Arcobacter, for which the name Arcobacter halophilus sp. nov. is proposed....... This is the first obligately halophilic member of the genus. The type strain is LA31B(T) (= ATCC BAA- 102 2 T=CIP 108450(T))....

  1. Use of MALDI-TOF Mass Spectrometry for the Fast Identification of Gram-Positive Fish Pathogens

    Science.gov (United States)

    Assis, Gabriella B. N.; Pereira, Felipe L.; Zegarra, Alexandra U.; Tavares, Guilherme C.; Leal, Carlos A.; Figueiredo, Henrique C. P.

    2017-01-01

    Gram-positive cocci, such as Streptococcus agalactiae, Lactococcus garvieae, Streptococcus iniae, and Streptococcus dysgalactiae subsp. dysgalactiae, are found throughout the world, particularly in outbreaks in farmed fish, and are thus associated with high economic losses, especially in the cultivation of Nile Tilapia. The aim of this study was to evaluate the efficacy of matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) as an alternative for the diagnosis of these pathogens. One hundred and thirty-one isolates from Brazilian outbreaks assisted by the national authority were identified using a MALDI Biotyper from Bruker Daltonics. The results showed an agreement with respect to identification (Kappa = 1) between this technique and 16S ribosomal RNA gene sequencing for S. agalactiae and L. garvieae. However, for S. iniae and S. dysgalactiae subsp. dysgalactiae, perfect agreement was only achieved after the creation of a custom main spectra profile, as well as further comparisons with 16S ribosomal RNA and multilocus sequence analysis. MALDI-TOF MS was shown to be an efficient technology for the identification of these Gram-positive pathogens, yielding a quick and precise diagnosis. PMID:28848512

  2. Production of surfactant and detergent-stable, halophilic, and alkalitolerant alpha-amylase by a moderately halophilic Bacillus sp. Strain TSCVKK.

    Science.gov (United States)

    Kiran, Kondepudi Kanthi; Chandra, T S

    2008-01-01

    A moderately halophilic alkalitolerant Bacillus sp. Strain TSCVKK, with an ability to produce extracellular halophilic, alkalitolerant, surfactant, and detergent-stable alpha-amylase was isolated from soil samples obtained from a salt-manufacturing industry in Chennai. The culture conditions for higher amylase production were optimized with respect to NaCl, substrate, pH, and temperature. Maximum amylase production of 592 mU/ml was achieved in the medium at 48 h with 10% NaCl, 1% dextrin, 0.4% yeast extract, 0.2% tryptone, and 0.2% CaCl(2) at pH 8.0 at 30 degrees C. The enzyme activity in the culture supernatant was highest with 10% NaCl at pH 7.5 and 55 degrees C. The amylase that was partially purified by acetone precipitation was highly stable in various surfactants and detergents. Glucose, maltose, and maltooligosaccharides were the main end products of starch hydrolysis indicating that it is an alpha-amylase.

  3. Neptunium(V) Adsorption to Bacteria at Low and High Ionic Strength

    Science.gov (United States)

    Ams, D.; Swanson, J. S.; Reed, D. T.

    2010-12-01

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO2+ aquo and associated complexed species, is readily soluble, interacts weakly with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface containment. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO2+) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacteria/Np mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria used were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. The observed adsorption behavior may be linked to similarities and differences in the characteristics of the moieties between the cell walls of common gram-negative soil and halophilic bacteria. Moreover, differences in adsorption behavior may also reflect ionic

  4. Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity.

    Science.gov (United States)

    Hecht, K; Wrba, A; Jaenicke, R

    1989-07-15

    Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes.

  5. Prediction of lipoprotein signal peptides in Gram-negative bacteria.

    Science.gov (United States)

    Juncker, Agnieszka S; Willenbrock, Hanni; Von Heijne, Gunnar; Brunak, Søren; Nielsen, Henrik; Krogh, Anders

    2003-08-01

    A method to predict lipoprotein signal peptides in Gram-negative Eubacteria, LipoP, has been developed. The hidden Markov model (HMM) was able to distinguish between lipoproteins (SPaseII-cleaved proteins), SPaseI-cleaved proteins, cytoplasmic proteins, and transmembrane proteins. This predictor was able to predict 96.8% of the lipoproteins correctly with only 0.3% false positives in a set of SPaseI-cleaved, cytoplasmic, and transmembrane proteins. The results obtained were significantly better than those of previously developed methods. Even though Gram-positive lipoprotein signal peptides differ from Gram-negatives, the HMM was able to identify 92.9% of the lipoproteins included in a Gram-positive test set. A genome search was carried out for 12 Gram-negative genomes and one Gram-positive genome. The results for Escherichia coli K12 were compared with new experimental data, and the predictions by the HMM agree well with the experimentally verified lipoproteins. A neural network-based predictor was developed for comparison, and it gave very similar results. LipoP is available as a Web server at www.cbs.dtu.dk/services/LipoP/.

  6. Production of an extracellular thermohalophilic lipase from a moderately halophilic bacterium, Salinivibrio sp. strain SA-2.

    Science.gov (United States)

    Amoozegar, Mohammad Ali; Salehghamari, Ensieh; Khajeh, Khosro; Kabiri, Mahbube; Naddaf, Saied

    2008-06-01

    Fifty strains of moderately halophilic bacteria were isolated from various salty environments in Iran. A strain designated as SA-2 was shown to be the best producer of extracellular lipase and was selected for further studies. Biochemical and physiological characterization along with 16S rDNA sequence analysis placed SA-2 in the genus Salinivibrio. The optimum salt, pH, temperature and aeration for enzyme production were 0.1 M KCl, pH 8, 35 degrees C and 150 rpm, respectively. The enzyme production was synchronized bacterial growth and reached a maximum level during the early-stationary phase in the basal medium containing 1 M NaCl. Triacylglycerols enhanced lipase production, while carbohydrates had inhibitory effects on it. The maximum lipase activity was obtained at pH 7.5, 50 degrees C and CaCl(2) concentration of 0.01 M. The enzyme was stable at pH range of 7.5-8 and retained 90% of its activity at 80 degrees C for 30 min. Different concentrations of NaNO(3), Na(2)SO(4), KCl and NaCl had no affect on lipase stability for 3 h. These results suggest that the lipase secreted by Salinivibrio sp. strain SA-2 is industrially important from the perspective of its tolerance to a broad temperature range, its moderate thermoactivity and its high tolerance to a wide range of salt concentrations (0-3 M NaCl).

  7. Life under Multiple Extreme Conditions: Diversity and Physiology of the Halophilic Alkalithermophiles

    Science.gov (United States)

    Wiegel, Juergen

    2012-01-01

    Around the world, there are numerous alkaline, hypersaline environments that are heated either geothermally or through intense solar radiation. It was once thought that such harsh environments were inhospitable and incapable of supporting a variety of life. However, numerous culture-dependent and -independent studies revealed the presence of an extensive diversity of aerobic and anaerobic bacteria and archaea that survive and grow under these multiple harsh conditions. This diversity includes the halophilic alkalithermophiles, a novel group of polyextremophiles that require for growth and proliferation the multiple extremes of high salinity, alkaline pH, and elevated temperature. Life under these conditions undoubtedly involves the development of unique physiological characteristics, phenotypic properties, and adaptive mechanisms that enable control of membrane permeability, control of intracellular osmotic balance, and stability of the cell wall, intracellular proteins, and other cellular constituents. This minireview highlights the ecology and growth characteristics of the extremely halophilic alkalithermophiles that have been isolated thus far. Biochemical, metabolic, and physiological properties of the extremely halophilic alkalithermophiles are described, and their roles in resistance to the combined stressors of high salinity, alkaline pH, and high temperature are discussed. The isolation of halophilic alkalithermophiles broadens the physicochemical boundaries for life and extends the boundaries for the combinations of the maximum salinity, pH, and temperature that can support microbial growth. PMID:22492435

  8. First characterization of extremely halophilic 2-deoxy-D-ribose-5-phosphate aldolase.

    Science.gov (United States)

    Ohshida, Tatsuya; Hayashi, Junji; Satomura, Takenori; Kawakami, Ryushi; Ohshima, Toshihisa; Sakuraba, Haruhiko

    2016-10-01

    2-Deoxy-d-ribose-5-phosphate aldolase (DERA) catalyzes the aldol reaction between two aldehydes and is thought to be a potential biocatalyst for the production of a variety of stereo-specific materials. A gene encoding DERA from the extreme halophilic archaeon, Haloarcula japonica, was overexpressed in Escherichia coli. The gene product was successfully purified, using procedures based on the protein's halophilicity, and characterized. The expressed enzyme was stable in a buffer containing 2 M NaCl and exhibited high thermostability, retaining more than 90% of its activity after heating at 70 °C for 10 min. The enzyme was also tolerant to high concentrations of organic solvents, such as acetonitrile and dimethylsulfoxide. Moreover, H. japonica DERA was highly resistant to a high concentration of acetaldehyde and retained about 35% of its initial activity after 5-h' exposure to 300 mM acetaldehyde at 25 °C, the conditions under which E. coli DERA is completely inactivated. The enzyme exhibited much higher activity at 25 °C than the previously characterized hyperthermophilic DERAs (Sakuraba et al., 2007). Our results suggest that the extremely halophilic DERA has high potential to serve as a biocatalyst in organic syntheses. This is the first description of the biochemical characterization of a halophilic DERA. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. High-level fluorescence labeling of gram-positive pathogens.

    Directory of Open Access Journals (Sweden)

    Simone Aymanns

    Full Text Available Fluorescence labeling of bacterial pathogens has a broad range of interesting applications including the observation of living bacteria within host cells. We constructed a novel vector based on the E. coli streptococcal shuttle plasmid pAT28 that can propagate in numerous bacterial species from different genera. The plasmid harbors a promoterless copy of the green fluorescent variant gene egfp under the control of the CAMP-factor gene (cfb promoter of Streptococcus agalactiae and was designated pBSU101. Upon transfer of the plasmid into streptococci, the bacteria show a distinct and easily detectable fluorescence using a standard fluorescence microscope and quantification by FACS-analysis demonstrated values that were 10-50 times increased over the respective controls. To assess the suitability of the construct for high efficiency fluorescence labeling in different gram-positive pathogens, numerous species were transformed. We successfully labeled Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. equisimilis, Enterococcus faecalis, Enterococcus faecium, Streptococcus mutans, Streptococcus anginosus and Staphylococcus aureus strains utilizing the EGFP reporter plasmid pBSU101. In all of these species the presence of the cfb promoter construct resulted in high-level EGFP expression that could be further increased by growing the streptococcal and enterococcal cultures under high oxygen conditions through continuous aeration.

  10. A Comparative biochemical study on two marine endophytes, Bacterium SRCnm and Bacillus sp. JS, Isolated from red sea algae.

    Science.gov (United States)

    Ahmed, Eman Fadl; Hassan, Hossam Mokhtar; Rateb, Mostafa Ezzat; Abdel-Wahab, Noha; Sameer, Somayah; Aly Taie, Hanan Anwar; Abdel-Hameed, Mohammed Sayed; Hammouda, Ola

    2016-01-01

    Two marine endophytic bacteria were isolated from the Red Sea algae; a red alga; Acanthophora dendroides and the brown alga Sargassum sabrepandum. The isolates were identified based on their 16SrRNA sequences as Bacterium SRCnm and Bacillus sp. JS. The objective of this study was to investigate the potential anti-microbial and antioxidant activities of the extracts of the isolated bacteria grown in different nutrient conditions. Compared to amoxicillin (25μg/disk) and erythromycin (15μg/disk), the extracts of Bacterium SRCn min media II, III, IV and V were potent inhibitors of the gram-positive bacterium Sarcina maxima even at low concentrations. Also, the multidrug resistant Staphylococcus aureus(MRSA) was more sensitive to the metabolites produced in medium (II) of the same endophyte than erythromycin (15μg/disk). A moderate activity of the Bacillus sp. JS extracts of media I and II was obtained against the same pathogen. The total compounds (500ug/ml) of both isolated endophytes showed moderate antioxidant activities (48.9% and 46.1%, respectively). LC/MS analysis of the bacterial extracts was carried out to investigate the likely natural products produced. Cyclo(D-cis-Hyp-L-Leu), dihydrosphingosine and 2-Amino-1,3-hexadecanediol were identified in the fermentation medium of Bacterium SRCnm, whereas cyclo (D-Pro-L-Tyr) and cyclo (L-Leu-L-Pro) were the suggested compounds of Bacillus sp. JS.

  11. Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea.

    Science.gov (United States)

    Jones, Daniel L; Baxter, Bonnie K

    2016-09-02

    Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additional photoprotective strategy. The predominant forms of UV-induced DNA damage are cyclobutane pyrimidine dimers, most notoriously thymine dimers (T^Ts), which form at adjacent Ts. We tested whether the high G + C content seen in halophilic archaea serves a photoprotective function through limiting T nucleotides, and thus T^T lesions. However, this speculation overlooks the other bipyrimidine sequences, all of which capable of forming photolesions to varying degrees. Therefore, we designed a program to determine the frequencies of the four bipyrimidine pairs (5' to 3': TT, TC, CT, and CC) within genomes of halophilic archaea and four other randomized sample groups for comparison. The outputs for each sampled genome were weighted by the intrinsic photoreactivities of each dinucleotide pair. Statistical methods were employed to investigate intergroup differences. Our findings indicate that the UV-resistance seen in halophilic archaea can be attributed in part to a genomic strategy: high G + C content and the resulting bipyrimidine signature reduces the genomic photoreactivity.

  12. Crystallization and preliminary X-ray analysis of three dUTPases from Gram-positive bacteria

    International Nuclear Information System (INIS)

    Li, Gui-Lan; Wang, Juan; Li, Lan-Fen; Su, Xiao-Dong

    2009-01-01

    All organisms examined to date possess a dUTPase that performs the important function of efficiently hydrolyzing dUTP to dUMP in order to prevent the incorporation of dUTP into DNA. Three putative dUTPases from Gram-positive bacteria have been studied in this work. All organisms examined to date possess a dUTPase that performs the important function of efficiently hydrolyzing dUTP to dUMP in order to prevent the incorporation of dUTP into DNA. Three putative dUTPases from Gram-positive bacteria have been studied in this work. Two dUTPase-encoding genes, yncF and yosS, have been identified in Bacillus subtilis. The gene dut, encoding dUTPase from the dental pathogen Streptococcus mutans, was amplified from S. mutans genomic DNA. The three genes were cloned into expression vectors and overexpressed at high levels in Escherichia coli. Each protein was purified in two steps using chromatographic methods. Crystals of the YosS and YncF proteins and of S. mutans dUTPase were obtained using the vapour-diffusion method. X-ray diffraction data sets were collected from crystals of selenomethionine-labelled YosS and S. mutans dUTPase to resolutions of 2.3 and 1.7 Å, respectively. The crystal of native YncF diffracted to 2.7 Å resolution

  13. Gram staining apparatus for space station applications

    Science.gov (United States)

    Molina, T. C.; Brown, H. D.; Irbe, R. M.; Pierson, D. L.

    1990-01-01

    A self-contained, portable Gram staining apparatus (GSA) has been developed for use in the microgravity environment on board the Space Station Freedom. Accuracy and reproducibility of this apparatus compared with the conventional Gram staining method were evaluated by using gram-negative and gram-positive controls and different species of bacteria grown in pure cultures. A subsequent study was designed to assess the performance of the GSA with actual specimens. A set of 60 human and environmental specimens was evaluated with the GSA and the conventional Gram staining procedure. Data obtained from these studies indicated that the GSA will provide the Gram staining capability needed for the microgravity environment of space.

  14. Halophilic biohydrogen and 1,3-propanediol production from raw glycerol: A genomic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kivisto, A.

    2013-11-01

    Glycerol is produced in large amounts as a by-product in biodiesel industry (10 kg per 100 kg biodiesel). By-products and waste materials are typically economical substrates for bioprocesses. Furthermore, microorganisms are able to combine the degradation of organic material with production of a wide range of metabolites and other cellular products. The current biotechnological interest of industrial glycerol lies on bioprocesses yielding environmentally friendly energy carrier molecules (hydrogen, methane, ethanol, butanol) and reduced chemicals (1,3-propanediol, dihydroxyacetone). Industrial glycerol also called as raw or crude glycerol, however, is a challenging substrate for microorganisms due to its impurities including alcohol, soaps, salts and metals. Halophiles (the salt-loving microorganisms) require salt for growth and heavy metal resistances have been characterized for numerous halophiles. Therefore, halophiles are potentially useful for the utilization of raw glycerol from biodiesel waste streams without pre-processing. Another challenge for large-scale microbial bioprocesses is a potential contamination with unfavorable microorganisms. For example, H{sub 2}-producing systems tend to get contaminated with H{sub 2}-consuming microorganisms. Extremophiles are organisms that have been adapted for life under extreme conditions, such as high salinity, high or low temperature, asidic or basic pH, dryness or high pressure. For extremophilic pure cultures contamination and thus the need to ensure a sterile environment might not be a problem due to the extreme process conditions that efficiently prevent the growth of most other bacteria. In addition, hypersaline environments (above 12 % NaCl) do not support the growth of H{sub 2} utilizing methanogens due to bioenergetic reasons. Halophilic fermentative H{sub 2} producers, on the other hand, have been shown to be active up to near salt saturation. The aims of the present study can be divided into two categories

  15. Isolation and characterization of extreme halophilic archaea

    Energy Technology Data Exchange (ETDEWEB)

    Franze, Madlen; Cherkouk, Andrea [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). HZDR Young Investigator Group

    2017-06-01

    Extreme halophilic archaea from the family Halobactereacea represent a dominant part of the microbial community present in saline soils as well as rock salts. By using a culture-dependent approach different Haloarchaea could be isolated and were phylogenetic analysed. Interestingly, isolates closely related to different Halobacterium spp. were found in both environments.

  16. Isolation and characterization of extreme halophilic archaea

    International Nuclear Information System (INIS)

    Franze, Madlen; Cherkouk, Andrea

    2017-01-01

    Extreme halophilic archaea from the family Halobactereacea represent a dominant part of the microbial community present in saline soils as well as rock salts. By using a culture-dependent approach different Haloarchaea could be isolated and were phylogenetic analysed. Interestingly, isolates closely related to different Halobacterium spp. were found in both environments.

  17. Candidatus Renichlamydia lutjani, a Gram-negative bacterium in internal organs of blue striped snapper Lutjanus kasmira from Hawaii

    Science.gov (United States)

    Corsaro, Daniele; Work, Thierry M.

    2012-01-01

    The blue-striped snapper Lutjanus kasmira (Perciformes, Lutjanidae) are cosmopolitan in the Indo-Pacific but were introduced into Oahu, Hawaii, USA, in the 1950s and have since colonized most of the archipelago. Studies of microparasites in blue-striped snappers from Hawaii revealed chlamydia-like organisms (CLO) infecting the spleen and kidney, characterized by intracellular basophilic granular inclusions containing Gram-negative and Gimenez-positive bacteria similar in appearance to epitheliocysts when seen under light microscopy. We provide molecular evidence that CLO are a new member of Chlamydiae, i.e. Candidatus Renichlamydia lutjani, that represents the first reported case of chlamydial infection in organs other than the gill in fishes.

  18. Performance and mechanism of standard nano-TiO2(P-25) in photocatalytic disinfection of foodborne microorganisms - salmonella typhimurium and listeria monocytogenes

    Science.gov (United States)

    In this paper, effects of disinfection by nano-TiO2 were studied on the two typical foodborne microorganisms, Gram-negative bacterium Salmonella typhimurium and Gram-positive bacterium-Listeria monocytogenes, in meat products. The performance of nano-TiO2 against the foodborne pathogens was evaluate...

  19. Heavy Metal uptake Potentials of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Uptake of heavy metals, silver and cadmium by Pseudomonas aeruginosa (a Gram negative bacterium) and Micrococcus luteus (a Gram positive bacterium) was investigated in Cadmium and Silver stock solution using ion selective electrodes. Silver and cadmium uptake by the two organisms was described by Langmuir ...

  20. Antagonistic Properties of Some Halophilic Thermoactinomycetes Isolated from Superficial Sediment of a Solar Saltern and Production of Cyclic Antimicrobial Peptides by the Novel Isolate Paludifilum halophilum

    Science.gov (United States)

    Frikha Dammak, Donyez; Zarai, Ziad; Najah, Soumaya; Abdennabi, Rayed; Belbahri, Lassaad; Rateb, Mostafa E.; Mejdoub, Hafedh

    2017-01-01

    This study has focused on the isolation of twenty-three halophilic actinomycetes from two ponds of different salinity and the evaluation of their ability to exert an antimicrobial activity against both their competitors and several other pathogens. From the 23 isolates, 18 strains showed antagonistic activity, while 19 showed activities against one or more of the seven pathogen strains tested. Six strains exhibited consistent antibacterial activity against Gram-negative and Gram-positive pathogens characterized at the physiological and molecular levels. These strains shared only 94-95% 16S rRNA sequence identity with the closely related species of the Thermoactinomycetaceae family. Among them, the potent strain SMBg3 was further characterized and assigned to a new genus in the family for which the name Paludifilum halophilum (DSM 102817T) is proposed. Sequential extraction of the antimicrobial compounds with ethyl acetate revealed that the crude extract from SMBg3 strain had inhibitory effect on the growth of the plant pathogen Agrobacterium tumefaciens and the human pathogens Staphylococcus aureus, Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa. Based on the HRESI-MS spectral data, the cyclic lipopeptide Gramicidin S and four cyclic dipeptides (CDPs) named cyclo(L-4-OH-Pro-L-Leu), cyclo(L-Tyr-L-Pro), cyclo(L-Phe-L-Pro), and cyclo(L-Leu-L-Pro) were detected in the fermentation broth of Paludifilum halophilum. To our knowledge, this is the first report on the isolation of these compounds from members of the Thermoactinomycetaceae family. PMID:28819625

  1. A Flexible Binding Site Architecture Provides New Insights into CcpA Global Regulation in Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Yunpeng Yang

    2017-01-01

    Full Text Available Catabolite control protein A (CcpA is the master regulator in Gram-positive bacteria that mediates carbon catabolite repression (CCR and carbon catabolite activation (CCA, two fundamental regulatory mechanisms that enable competitive advantages in carbon catabolism. It is generally regarded that CcpA exerts its regulatory role by binding to a typical 14- to 16-nucleotide (nt consensus site that is called a catabolite response element (cre within the target regions. However, here we report a previously unknown noncanonical flexible architecture of the CcpA-binding site in solventogenic clostridia, providing new mechanistic insights into catabolite regulation. This novel CcpA-binding site, named crevar, has a unique architecture that consists of two inverted repeats and an intervening spacer, all of which are variable in nucleotide composition and length, except for a 6-bp core palindromic sequence (TGTAAA/TTTACA. It was found that the length of the intervening spacer of crevar can affect CcpA binding affinity, and moreover, the core palindromic sequence of crevar is the key structure for regulation. Such a variable architecture of crevar shows potential importance for CcpA’s diverse and fine regulation. A total of 103 potential crevar sites were discovered in solventogenic Clostridium acetobutylicum, of which 42 sites were picked out for electrophoretic mobility shift assays (EMSAs, and 30 sites were confirmed to be bound by CcpA. These 30 crevar sites are associated with 27 genes involved in many important pathways. Also of significance, the crevar sites are found to be widespread and function in a great number of taxonomically different Gram-positive bacteria, including pathogens, suggesting their global role in Gram-positive bacteria.

  2. Antimicrobial susceptibility trends among gram-positive and -negative clinical isolates collected between 2005 and 2012 in Mexico: results from the Tigecycline Evaluation and Surveillance Trial.

    Science.gov (United States)

    Morfin-Otero, Rayo; Noriega, Eduardo Rodriguez; Dowzicky, Michael J

    2015-12-15

    The Tigecycline Evaluation and Surveillance Trial (T.E.S.T) is a global antimicrobial surveillance study of both gram-positive and gram-negative organisms. This report presents data on antimicrobial susceptibility among organisms collected in Mexico between 2005 and 2012 as part of T.E.S.T., and compares rates between 2005-2007 and 2008-2012. Each center in Mexico submitted at least 200 isolates per collection year; including 65 gram-positive isolates and 135 gram-negative isolates. Minimum inhibitory concentrations (MICs) were determined using Clinical Laboratory Standards Institute (CLSI) broth microdilution methodology and antimicrobial susceptibility was established using the 2013 CLSI-approved breakpoints. For tigecycline US Food and Drug Administration (FDA) breakpoints were applied. Isolates of E. coli and K. pneumoniae with a MIC for ceftriaxone of >1 mg/L were screened for ESBL production using the phenotypic confirmatory disk test according to CLSI guidelines. The rates of some key resistant phenotypes changed during this study: vancomycin resistance among Enterococcus faecium decreased from 28.6 % in 2005-2007 to 19.1 % in 2008-2012, while β-lactamase production among Haemophilus influenzae decreased from 37.6 to 18.9 %. Conversely, methicillin-resistant Staphylococcus aureus increased from 38.1 to 47.9 %, meropenem-resistant Acinetobacter spp. increased from 17.7 to 33.0 % and multidrug-resistant Acinetobacter spp. increased from 25.6 to 49.7 %. The prevalence of other resistant pathogens was stable over the study period, including extended-spectrum β-lactamase-positive Escherichia coli (39.0 %) and Klebsiella pneumoniae (25.0 %). The activity of tigecycline was maintained across the study years with MIC90s of ≤2 mg/L against Enterococcus spp., S. aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Enterobacter spp., E. coli, K. pneumoniae, Klebsiella oxytoca, Serratia marcescens, H. influenzae, and Acinetobacter spp. All gram-positive

  3. Thermotoga lettingae sp. nov. : a novel thermophilic, methanol-degrading bacterium isolated from a thermophilic anaerobic reactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Stams, A.J.M.

    2002-01-01

    A novel, anaerobic, non-spore-forming, mobile, Gram-negative, thermophilic bacterium, strain TMO(T), was isolated from a thermophilic sulfate-reducing bioreactor operated at 65 degrees C with methanol as the sole substrate. The G C content of the DNA of strain TMO(T) was 39.2 molÐThe optimum pH,

  4. Structural evidence for solvent-stabilisation by aspartic acid as a mechanism for halophilic protein stability in high salt concentrations.

    Science.gov (United States)

    Lenton, Samuel; Walsh, Danielle L; Rhys, Natasha H; Soper, Alan K; Dougan, Lorna

    2016-07-21

    Halophilic organisms have adapted to survive in high salt environments, where mesophilic organisms would perish. One of the biggest challenges faced by halophilic proteins is the ability to maintain both the structure and function at molar concentrations of salt. A distinct adaptation of halophilic proteins, compared to mesophilic homologues, is the abundance of aspartic acid on the protein surface. Mutagenesis and crystallographic studies of halophilic proteins suggest an important role for solvent interactions with the surface aspartic acid residues. This interaction, between the regions of the acidic protein surface and the solvent, is thought to maintain a hydration layer around the protein at molar salt concentrations thereby allowing halophilic proteins to retain their functional state. Here we present neutron diffraction data of the monomeric zwitterionic form of aspartic acid solutions at physiological pH in 0.25 M and 2.5 M concentration of potassium chloride, to mimic mesophilic and halophilic-like environmental conditions. We have used isotopic substitution in combination with empirical potential structure refinement to extract atomic-scale information from the data. Our study provides structural insights that support the hypothesis that carboxyl groups on acidic residues bind water more tightly under high salt conditions, in support of the residue-ion interaction model of halophilic protein stabilisation. Furthermore our data show that in the presence of high salt the self-association between the zwitterionic form of aspartic acid molecules is reduced, suggesting a possible mechanism through which protein aggregation is prevented.

  5. Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity

    Directory of Open Access Journals (Sweden)

    Sonika Gupta

    2016-01-01

    Full Text Available The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products.

  6. Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity.

    Science.gov (United States)

    Gupta, Sonika; Sharma, Parul; Dev, Kamal; Sourirajan, Anuradha

    2016-01-01

    The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products.

  7. Veillonella, Firmicutes: Microbes disguised as Gram negatives.

    Science.gov (United States)

    Vesth, Tammi; Ozen, Aslı; Andersen, Sandra C; Kaas, Rolf Sommer; Lukjancenko, Oksana; Bohlin, Jon; Nookaew, Intawat; Wassenaar, Trudy M; Ussery, David W

    2013-12-20

    The Firmicutes represent a major component of the intestinal microflora. The intestinal Firmicutes are a large, diverse group of organisms, many of which are poorly characterized due to their anaerobic growth requirements. Although most Firmicutes are Gram positive, members of the class Negativicutes, including the genus Veillonella, stain Gram negative. Veillonella are among the most abundant organisms of the oral and intestinal microflora of animals and humans, in spite of being strict anaerobes. In this work, the genomes of 24 Negativicutes, including eight Veillonella spp., are compared to 20 other Firmicutes genomes; a further 101 prokaryotic genomes were included, covering 26 phyla. Thus a total of 145 prokaryotic genomes were analyzed by various methods to investigate the apparent conflict of the Veillonella Gram stain and their taxonomic position within the Firmicutes. Comparison of the genome sequences confirms that the Negativicutes are distantly related to Clostridium spp., based on 16S rRNA, complete genomic DNA sequences, and a consensus tree based on conserved proteins. The genus Veillonella is relatively homogeneous: inter-genus pair-wise comparison identifies at least 1,350 shared proteins, although less than half of these are found in any given Clostridium genome. Only 27 proteins are found conserved in all analyzed prokaryote genomes. Veillonella has distinct metabolic properties, and significant similarities to genomes of Proteobacteria are not detected, with the exception of a shared LPS biosynthesis pathway. The clade within the class Negativicutes to which the genus Veillonella belongs exhibits unique properties, most of which are in common with Gram-positives and some with Gram negatives. They are only distantly related to Clostridia, but are even less closely related to Gram-negative species. Though the Negativicutes stain Gram-negative and possess two membranes, the genome and proteome analysis presented here confirm their place within the

  8. Characterization of detergent compatible protease from halophilic Virgibacillus sp. CD6.

    Science.gov (United States)

    Lam, Ming Quan; Nik Mut, Nik Nurhidayu; Thevarajoo, Suganthi; Chen, Sye Jinn; Selvaratnam, Chitra; Hussin, Huszalina; Jamaluddin, Haryati; Chong, Chun Shiong

    2018-02-01

    A halophilic bacterium, Virgibacillus sp. strain CD6, was isolated from salted fish and its extracellular protease was characterized. Protease production was found to be highest when yeast extract was used as nitrogen source for growth. The protease exhibited stability at wide range of salt concentration (0-12.5%, w/v), temperatures (20-60 °C), and pH (4-10) with maximum activity at 10.0% (w/v) NaCl, 60 °C, pH 7 and 10, indicating its polyextremophilicity. The protease activity was enhanced in the presence of Mg 2+ , Mn 2+ , Cd 2+ , and Al 3+ (107-122% relative activity), and with retention of activity > 80% for all of other metal ions examined (K + , Ca 2+ , Cu 2+ , Co 2+ , Ni 2+ , Zn 2+ , and Fe 3+ ). Both PMSF and EDTA inhibited protease activity, denoting serine protease and metalloprotease properties, respectively. High stability (> 70%) was demonstrated in the presence of organic solvents and detergent constituents, and the extracellular protease from strain CD6 was also found to be compatible in commercial detergents. Proteinaceous stain removal efficacy revealed that crude protease of strain CD6 could significantly enhance the performance of commercial detergent. The protease from Virgibacillus sp. strain CD6 could serve as a promising alternative for various applications, especially in detergent industry.

  9. A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria

    Science.gov (United States)

    Quiles-Puchalt, Nuria; Tormo-Más, María Ángeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Íñigo; Novick, Richard P.; Christie, Gail E.; Penadés, José R.

    2013-01-01

    The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. PMID:23771138

  10. Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field

    DEFF Research Database (Denmark)

    Tanaka, Reiji; Kawaichi, Satoshi; Nishimura, Hiroshi

    2006-01-01

    A novel thermophilic bacterium, strain KW1T, was isolated from a coastal hydrothermal field on the Satsuma Peninsula, Kagoshima Prefecture, Japan. The variably Gram-stained cells were motile rods with flagella, did not form spores and proliferated at 52-78°C (optimum, 70°C), pH 5-8 (optimum, pH 7...

  11. Extracellular Electron Transfer Mediated by Flavins in Gram-positive Bacillus sp. WS-XY1 and Yeast Pichia stipitis

    International Nuclear Information System (INIS)

    Wu, Song; Xiao, Yong; Wang, Lu; Zheng, Yue; Chang, Kenlin; Zheng, Zhiyong; Yang, Zhaohui; Varcoe, John R.; Zhao, Feng

    2014-01-01

    Extracellular electron transfer (EET) of microorganisms represents a communicative bridge between the interior and exterior of the cells. Most prior EET studies have focused on Gram-negative bacteria. However, fungi and Gram-positive bacteria, that contain dense cellular walls, have rarely been reported. Herein, two model dense cell wall microorganisms (Bacillus sp. WS-XY1 and the yeast Pichia stipitis) were identified to be electrochemically active. Further analysis indicated that the two microorganisms were able to secrete flavins to mediate their EET. The discovery, that dense cell wall containing microorganisms can undertake mediated EET, adds to the body of knowledge towards building a comprehensive understanding of biogeochemical and bioelectrical processes

  12. Antimicrobial effects of zero-valent iron nanoparticles on gram-positive Bacillus strains and gram-negative Escherichia coli strains

    Directory of Open Access Journals (Sweden)

    Yi-Huang Hsueh

    2017-11-01

    Full Text Available Abstract Background Zero-valent iron nanoparticles (ZVI NPs have been used extensively for the remediation of contaminated soil and groundwater. Owing to their large active surface area, they serve as strong and effective reductants. However, the ecotoxicity and bioavailability of ZVI NPs in diverse ecological media have not been evaluated in detail and most studies have focused on non-nano ZVI or Fe0. In addition, the antimicrobial properties of ZVI NPs have rarely been investigated, and the underlying mechanism of their toxicity remains unknown. Results In the present study, we demonstrate that ZVI NPs exhibited significant toxicity at 1000 ppm against two distinct gram-positive bacterial strains (Bacillus subtilis 3610 and Bacillus thuringiensis 407 but not against two gram-negative strains (Escherichia coli K12 and ATCC11634. Specifically, ZVI NPs caused at least a 4-log and 1-log reductions in cell numbers, respectively, in the two Bacillus strains, whereas no change was detected in the two E. coli strains. X-ray photoelectron spectroscopy, X-ray absorption near-edge, and extended X-ray absorption fine structure spectra confirmed that Bacillus cells exposed to ZVI NPs contained mostly Fe2O3 with some detectable FeS. This finding indicated that Fe0 nanoparticles penetrated the bacterial cells, where they were subsequently oxidized to Fe2O3 and FeS. RedoxSensor analysis and propidium iodide (PI staining showed decreased reductase activity and increased PI in both Bacillus strains treated with a high (1000 ppm concentration of ZVI NPs. Conclusion Taken together, these data show that the toxicity of ZVI NPs was derived from their oxidative properties, which may increase the levels of reactive oxygen species and lead to cell death.

  13. A fatal endocarditis case due to an emerging bacterium: Moraxella nonliquefaciens

    Directory of Open Access Journals (Sweden)

    C. Duployez

    2017-01-01

    Full Text Available Moraxella nonliquefaciens is a Gram-negative coccobacillus considered as a commensal organism from the upper respiratory tract, with low pathogenic potential. The phenotypical conventional identification is difficult and the matrix-assisted laser desorption/ionization time-of-flight technology has increased the resolution of identification of this bacterium. We report a fatal case of endocarditis due to M. nonliquefaciens whose identification was confirmed by 16S rRNA, and we review the literature on this pathogen in endocarditis.

  14. Partial genome sequence of Thioalkalivibrio thiocyanodenitrificans ARhD 1T, a chemolithoautotrophic haloalkaliphilic sulfur-oxidizing bacterium capable of complete denitrification

    NARCIS (Netherlands)

    Berben, T.; Sorokin, D.Y.; Ivanova, N.; Pati, A.; Kyrpides, N.; Goodwin, L.A; Woyke, T.; Muyzer, G.

    2015-01-01

    Thioalkalivibrio thiocyanodenitrificans strain ARhD 1 T is a motile, Gram-negative bacterium isolated from soda lakes that belongs to the Gammaproteobacteria. It derives energy for growth and carbon fixation from the oxidation of sulfur compounds, most notably thiocyanate, and so is a

  15. Cyclic Di-GMP Binding by an Assembly ATPase (PilB2) and Control of Type IV Pilin Polymerization in the Gram-Positive Pathogen Clostridium perfringens.

    Science.gov (United States)

    Hendrick, William A; Orr, Mona W; Murray, Samantha R; Lee, Vincent T; Melville, Stephen B

    2017-05-15

    The Gram-positive pathogen Clostridium perfringens possesses type IV pili (TFP), which are extracellular fibers that are polymerized from a pool of pilin monomers in the cytoplasmic membrane. Two proteins that are essential for pilus functions are an assembly ATPase (PilB) and an inner membrane core protein (PilC). Two homologues each of PilB and PilC are present in C. perfringens , called PilB1/PilB2 and PilC1/PilC2, respectively, along with four pilin proteins, PilA1 to PilA4. The gene encoding PilA2, which is considered the major pilin based on previous studies, is immediately downstream of the pilB2 and pilC2 genes. Purified PilB2 had ATPase activity, bound zinc, formed hexamers even in the absence of ATP, and bound the second messenger molecule cyclic di-GMP (c-di-GMP). Circular dichroism spectroscopy of purified PilC2 indicated that it retained its predicted degree of alpha-helical secondary structure. Even though no direct interactions between PilB2 and PilC2 could be detected in vivo or in vitro even in the presence of c-di-GMP, high levels of expression of a diguanylate cyclase from C. perfringens (CPE1788) stimulated polymerization of PilA2 in a PilB2- and PilC2-dependent manner. These results suggest that PilB2 activity is controlled by c-di-GMP levels in vivo but that PilB2-PilC2 interactions are either transitory or of low affinity, in contrast to results reported previously from in vivo studies of the PilB1/PilC1 pair in which PilC1 was needed for polar localization of PilB1. This is the first biochemical characterization of a c-di-GMP-dependent assembly ATPase from a Gram-positive bacterium. IMPORTANCE Type IV pili (TFP) are protein fibers involved in important bacterial functions, including motility, adherence to surfaces and host cells, and natural transformation. All clostridia whose genomes have been sequenced show evidence of the presence of TFP. The genetically tractable species Clostridium perfringens was used to study proteins involved in

  16. The effects of salinity on nitrification using halophilic nitrifiers in a Sequencing Batch Reactor treating hypersaline wastewater.

    Science.gov (United States)

    Cui, You-Wei; Zhang, Hong-Yu; Ding, Jie-Ran; Peng, Yong-Zhen

    2016-04-25

    With annual increases in the generation and use of saline wastewater, the need to avoid environmental problems such as eutrophication is critical. A previous study identified ways to start up a halophilic sludge domesticated from estuarine sediments to remove nitrogen from wastewater with a salinity of 30 g/L. This investigation expands that work to explore the impact of salinity on nitrogen removal. This study demonstrated that the mixed halophilic consortia removed nitrogen from wastewater with a salinity of 30-85 g/L. A kinetic analysis showed that halophilic nitrifiers selected based on hypersalinity were characterized by low Ks, μmax and specific ammonium oxidization rates. This explains the decrease in ammonium removal efficiency in the high salinity operational phases. Salinity inhibited ammonia oxidizing bacteria (AOB) activity, as well as the number of dominant AOB, but did not significantly affect the AOB dominant species. Three most dominant AOB lineages in the halophilic sludge were Nitrosomonas marina, Nitrosomonas europaea, and Nitrosococcus mobilis. Nitrosomonas europaea and Nitrosococcus mobilis were mainly affected by salinity, while nitrite accumulation and ammonia loading played the key role in determining the abundance of Nitrosococcus mobilis and Nitrosococcus europaea. The study contributes insights about shifts in halophilic nitrifying bacterial populations.

  17. Alternate gram staining technique using a fluorescent lectin.

    Science.gov (United States)

    Sizemore, R K; Caldwell, J J; Kendrick, A S

    1990-01-01

    Fluorescence-labeled wheat germ agglutinin binds specifically to N-acetylglucosamine in the outer peptidoglycan layer of gram-positive bacteria. The peptidoglycan layer of gram-negative bacteria is covered by a membrane and is not labeled by the lectin. By exploiting this phenomenon, an alternative Gram staining technique has been developed. Images PMID:1697149

  18. Inactivation of Lactobacillus plantarum in apple cider using radio frequency electric fields

    Science.gov (United States)

    Radio frequency electric fields (RFEF) processing is effective at inactivating Gram negative bacteria in fruit juices at moderately low temperatures, but has yet to be shown to be effective at reducing Gram positive bacteria. Lactobacillus plantarum ATCC 49445, a Gram positive bacterium, was inocula...

  19. Over a Decade of recA and tly Gene Sequence Typing of the Skin Bacterium Propionibacterium acnes: What Have We Learnt?

    Directory of Open Access Journals (Sweden)

    Andrew McDowell

    2017-12-01

    Full Text Available The Gram-positive, anaerobic bacterium Propionibacterium acnes forms part of the normal microbiota on human skin and mucosal surfaces. While normally associated with skin health, P. acnes is also an opportunistic pathogen linked with a range of human infections and clinical conditions. Over the last decade, our knowledge of the intraspecies phylogenetics and taxonomy of this bacterium has increased tremendously due to the introduction of DNA typing schemes based on single and multiple gene loci, as well as whole genomes. Furthermore, this work has led to the identification of specific lineages associated with skin health and human disease. In this review we will look back at the introduction of DNA sequence typing of P. acnes based on recA and tly loci, and then describe how these methods provided a basic understanding of the population genetic structure of the bacterium, and even helped characterize the grapevine-associated lineage of P. acnes, known as P. acnes type Zappe, which appears to have undergone a host switch from humans-to-plants. Particular limitations of recA and tly sequence typing will also be presented, as well as a detailed discussion of more recent, higher resolution, DNA-based methods to type P. acnes and investigate its evolutionary history in greater detail.

  20. [Community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan salt lake on Qinghai-Tibet Plateau].

    Science.gov (United States)

    Shen, Shuo

    2017-04-04

    I studied the community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan Salt Lake. I isolated and cultured the moderate halophilic bacteria on different selective media. After the 16S rRNA gene sequences was amplified and measured, I constructed the phylogenic tree, analyzed the community structure and calculated the diversity indexes according to the 16S rRNA gene information. A total of 421 moderate halophilic bacteria were isolated from water and mud samples in Qrhan Salt Lake. The 16S rRNA gene information showed that 4 potential novel species belonged to the family Bacillaceae. Eighty-three model strains belonged to 3 phylurms 6 families 16 genus. Among them, Bacillus sp., Oceanobacillus sp. and Halomonas sp. were dominant species. Diversity analysis showed that the diversity of strains isolated from water sample was higher than that from mud sample, but the dominance degree of strains isolated from mud sample was higher than that from water sample. The genetic diversity of moderate halophilic bacteria isolated from Qrhan Salt Lake was abundant. Also, there were dominant and novel species of culturable moderate halophilic bacteria in this lake.

  1. Antimicrobial Activities of Methanol, Ethanol and Supercritical CO2 Extracts of Philippine Piper betle L. on Clinical Isolates of Gram Positive and Gram Negative Bacteria with Transferable Multiple Drug Resistance.

    Directory of Open Access Journals (Sweden)

    Demetrio L Valle

    Full Text Available Piper betle L. has traditionally been used in alternative medicine in different countries for various therapeutic purposes, including as an anti-infective agent. However, studies reported in the literature are mainly on its activities on drug susceptible bacterial strains. This study determined the antimicrobial activities of its ethanol, methanol, and supercritical CO2 extracts on clinical isolates of multiple drug resistant bacteria which have been identified by the Infectious Disease Society of America as among the currently more challenging strains in clinical management. Assay methods included the standard disc diffusion method and the broth microdilution method for the determination of the minimum inhibitory concentration (MIC and the minimum bactericidal concentrations (MBC of the extracts for the test microorganisms. This study revealed the bactericidal activities of all the P. betle leaf crude extracts on methicillin-resistant Staphylococcus aureus (MRSA, vancomycin-resistant Enterococcus (VRE, extended spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii, with minimum bactericidal concentrations that ranged from 19μg/ml to 1250 μg/ml. The extracts proved to be more potent against the Gram positive MRSA and VRE than for the Gram negative test bacteria. VRE isolates were more susceptible to all the extracts than the MRSA isolates. Generally, the ethanol extracts proved to be more potent than the methanol extracts and supercritical CO2 extracts as shown by their lower MICs for both the Gram positive and Gram negative MDRs. MTT cytotoxicity assay showed that the highest concentration (100 μg/ml of P. betle ethanol extract tested was not toxic to normal human dermal fibroblasts (HDFn. Data from the study firmly established P. betle as an alternative source of anti-infectives against multiple drug resistant

  2. Antimicrobial Activities of Methanol, Ethanol and Supercritical CO2 Extracts of Philippine Piper betle L. on Clinical Isolates of Gram Positive and Gram Negative Bacteria with Transferable Multiple Drug Resistance.

    Science.gov (United States)

    Valle, Demetrio L; Cabrera, Esperanza C; Puzon, Juliana Janet M; Rivera, Windell L

    2016-01-01

    Piper betle L. has traditionally been used in alternative medicine in different countries for various therapeutic purposes, including as an anti-infective agent. However, studies reported in the literature are mainly on its activities on drug susceptible bacterial strains. This study determined the antimicrobial activities of its ethanol, methanol, and supercritical CO2 extracts on clinical isolates of multiple drug resistant bacteria which have been identified by the Infectious Disease Society of America as among the currently more challenging strains in clinical management. Assay methods included the standard disc diffusion method and the broth microdilution method for the determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) of the extracts for the test microorganisms. This study revealed the bactericidal activities of all the P. betle leaf crude extracts on methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii, with minimum bactericidal concentrations that ranged from 19μg/ml to 1250 μg/ml. The extracts proved to be more potent against the Gram positive MRSA and VRE than for the Gram negative test bacteria. VRE isolates were more susceptible to all the extracts than the MRSA isolates. Generally, the ethanol extracts proved to be more potent than the methanol extracts and supercritical CO2 extracts as shown by their lower MICs for both the Gram positive and Gram negative MDRs. MTT cytotoxicity assay showed that the highest concentration (100 μg/ml) of P. betle ethanol extract tested was not toxic to normal human dermal fibroblasts (HDFn). Data from the study firmly established P. betle as an alternative source of anti-infectives against multiple drug resistant bacteria.

  3. Desulfotomaculum spp. and related Gram-positive sulfate-reducing bacteria in deep subsurface environments.

    Directory of Open Access Journals (Sweden)

    Thomas eAullo

    2013-12-01

    Full Text Available Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2 and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review.

  4. Shortcut nitrification-denitrification by means of autochthonous halophilic biomass in an SBR treating fish-canning wastewater.

    Science.gov (United States)

    Capodici, Marco; Corsino, Santo Fabio; Torregrossa, Michele; Viviani, Gaspare

    2018-02-15

    Autochthonous halophilic biomass was cultivated in a sequencing batch reactor (SBR) aimed at analyzing the potential use of autochthonous halophilic activated sludge in treating saline industrial wastewater. Despite the high salt concentration (30 g NaCl L -1 ), biological oxygen demand (BOD) and total suspended solids (TSS), removal efficiencies were higher than 90%. More than 95% of the nitrogen was removed via a shortcut nitrification-denitrification process. Both the autotrophic and heterotrophic biomass samples exhibited high biological activity. The use of autochthonous halophilic biomass led to high-quality effluent and helped to manage the issues related to nitrogen removal in saline wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Effects of antibiotics and ultraviolet radiation on the halophilic blue-green alga

    International Nuclear Information System (INIS)

    Yopp, J.H.; Albright, G.; Miller, D.M.; Southern Illinois Univ., Carbondale

    1979-01-01

    The effects of a variety of antibiotics, ultraviolet radiation and N-methyl-N-nitro-N-nitro-N-nitrosoguanidine (NTG) on the survival and mutability of the halophilic blue-green alga, Aphanothece halophytica, were determined. The halophile was found extremely sensitive to penicillin G and bacitracin; moderately sensitive to novobiocin, amino acid analogs, chloramphenicol and streptomycin; and tolerant to actidione and hydroxyurea. Ultraviolet and NTG killing curves and photoreactivation capabilities were seimilar to those reported for other members of the Chroococcales. Three stable morphological mutants were obtained by ultraviolet and NTG treatment, the latter being much more efficient in the production of mutants. (orig.)

  6. Halomonas sp. BS4, A biosurfactant producing halophilic bacterium isolated from solar salt works in India and their biomedical importance.

    Science.gov (United States)

    Donio, Mariathason Birdilla Selva; Ronica, Fernando Arul; Viji, Vijayaragavan Thanga; Velmurugan, Subramanian; Jenifer, John Selesteen Charles Adlin; Michaelbabu, Mariavincent; Dhar, Prasenjit; Citarasu, Thavasimuthu

    2013-12-01

    Halophilic bacteria were isolated from Thamaraikulam solar salt works in India. After routine biosurfactant screening by various methods, the biosurfactant producing bacteria, Halomonas sp BS4 was confirmed by 16 S rRNA sequencing. The growth optimization of Halomonas sp BS4 revealed their optimum growth at 8% NaCl and 6-8 pH in the growth medium. Further the partially purified biosurfactants were characterized by TLC, FTIR and GC-MS analysis. GC-MS results revealed that, the partial purified biosurfactants contain 1, 2-Ethanediamine N, N, N', N'-tetra, 8-Methyl-6-nonenamide, (Z)-9-octadecenamide and a fatty acid derivative. Pharmacological screening of antibacterial, antifungal, antiviral and anticancer assays revealed that, the biosurfactant extracted from Halomonas sp BS4 effectively controlled the human pathogenic bacteria and fungi an aquaculturally important virus, WSSV. The biosurfactant also suppressed the proliferation of mammary epithelial carcinoma cell by 46.77% at 2.5 μg concentration. Based on these findings, the present study concluded that, there is a possibility to develop eco-friendly antimicrobial and anticancer drugs from the extremophilic origin.

  7. Curiously modern DNA for a "250 million-year-old" bacterium.

    Science.gov (United States)

    Nickle, David C; Learn, Gerald H; Rain, Matthew W; Mullins, James I; Mittler, John E

    2002-01-01

    Studies of ancient DNA have attracted considerable attention in scientific journals and the popular press. Several of the more extreme claims for ancient DNA have been questioned on biochemical grounds (i.e., DNA surviving longer than expected) and evolutionary grounds (i.e., nucleotide substitution patterns not matching theoretical expectations for ancient DNA). A recent letter to Nature from Vreeland et al. (2000), however, tops all others with respect to age and condition of the specimen. These researchers extracted and cultured a bacterium from an inclusion body from what they claim is a 250 million-year (Myr)-old salt crystal. If substantiated, this observation could fundamentally alter views about bacterial physiology, ecology and evolution. Here we report on molecular evolutionary analyses of the 16S rDNA from this specimen. We find that 2-9-3 differs from a modern halophile, Salibacillus marismortui, by just 3 unambiguous bp in 16S rDNA, versus the approximately 59 bp that would be expected if these bacteria evolved at the same rate as other bacteria. We show, using a Poisson distribution, that unless it can be shown that S. marismortui evolves 5 to 10 times more slowly than other bacteria for which 16S rDNA substitution rates have been established, Vreeland et al.'s claim would be rejected at the 0.05 level. Also, a molecular clock test and a relative rates test fail to substantiate Vreeland et al.'s claim that strain 2-9-3 is a 250-Myr-old bacterium. The report of Vreeland et al. thus falls into a long series of suspect ancient DNA studies.

  8. Gram staining with an automatic machine.

    Science.gov (United States)

    Felek, S; Arslan, A

    1999-01-01

    This study was undertaken to develop a new Gram-staining machine controlled by a micro-controller and to investigate the quality of slides that were stained in the machine. The machine was designed and produced by the authors. It uses standard 220 V AC. Staining, washing, and drying periods are controlled by a timer built in the micro-controller. A software was made that contains a certain algorithm and time intervals for the staining mode. One-hundred and forty smears were prepared from Escherichia coli, Staphylococcus aureus, Neisseria sp., blood culture, trypticase soy broth, direct pus and sputum smears for comparison studies. Half of the slides in each group were stained with the machine, the other half by hand and then examined by four different microbiologists. Machine-stained slides had a higher clarity and less debris than the hand-stained slides (p stained slides, some Gram-positive organisms showed poor Gram-positive staining features (p Gram staining with the automatic machine increases the staining quality and helps to decrease the work load in a busy diagnostic laboratory.

  9. Characterization of the surfaceome of the metal-reducing bacterium Desulfotomaculum reducens

    Directory of Open Access Journals (Sweden)

    Elena eDalla Vecchia

    2014-08-01

    Full Text Available Desulfotomaculum reducens strain MI-1 is a Gram-positive, sulfate-reducing bacterium also capable of reducing Fe(III. Metal reduction in Gram-positive bacteria is poorly understood. Here, we investigated Fe(III reduction with lactate, a non-fermentable substrate, as the electron donor. Lactate consumption is concomitant to Fe(III reduction, but does not support significant growth, suggesting that little energy can be conserved from this process and that it may occur fortuitously. D. reducens can reduce both soluble (Fe(III-citrate and insoluble (hydrous ferric oxide, HFO Fe(III. Because physically inaccessible HFO was not reduced, we concluded that reduction requires direct contact under these experimental conditions. This implies the presence of a surface exposed reductase capable of transferring electrons from the cell to the extracellular electron acceptor. With the goal of characterizing the role of surface proteins in D. reducens and of identifying candidate Fe(III reductases, we carried out an investigation of the surface proteome (surfaceome of D. reducens. Cell surface exposed proteins were extracted by trypsin cell shaving or by lysozyme treatment, and analyzed by liquid chromatography-tandem mass spectrometry. This investigation revealed that the surfaceome fulfills many functions, including solute transport, protein export, maturation and hydrolysis, peptidoglycan synthesis and modification, and chemotaxis. Furthermore, a few redox-active proteins were identified. Among these, three are putatively involved in Fe(III reduction, i.e., a membrane-bound hydrogenase 4Fe-4S cluster subunit (Dred_0462, a heterodisulfide reductase subunit A (Dred_0143 and a protein annotated as alkyl hydroperoxide reductase but likely functioning as a thiol-disulfide oxidoreductase (Dred_1533.

  10. A flow-cytometric gram-staining technique for milk-associated bacteria.

    Science.gov (United States)

    Holm, Claus; Jespersen, Lene

    2003-05-01

    A Gram-staining technique combining staining with two fluorescent stains, Oregon Green-conjugated wheat germ agglutinin (WGA) and hexidium iodide (HI) followed by flow-cytometric detection is described. WGA stains gram-positive bacteria while HI binds to the DNA of all bacteria after permeabilization by EDTA and incubation at 50 degrees C for 15 min. For WGA to bind to gram-positive bacteria, a 3 M potassium chloride solution was found to give the highest fluorescence intensity. A total of 12 strains representing some of the predominant bacterial species in bulk tank milk and mixtures of these were stained and analyzed by flow cytometry. Overall, the staining method showed a clear differentiation between gram-positive and gram-negative bacterial populations. For stationary-stage cultures of seven gram-positive bacteria and five gram-negative bacteria, an average of 99% of the cells were correctly interpreted. The method was only slightly influenced by the growth phase of the bacteria or conditions such as freezing at -18 degrees C for 24 h. For any of these conditions, an average of at least 95% of the cells were correctly interpreted. When stationary-stage cultures were stored at 5 degrees C for 14 days, an average of 86% of the cells were correctly interpreted. The Gram-staining technique was applied to the flow cytometry analysis of bulk tank milk inoculated with Staphylococcus aureus and Escherichia coli. These results demonstrate that the technique is suitable for analyzing milk samples without precultivation.

  11. Facile synthesis of gold nanoparticles on propylamine functionalized SBA-15 and effect of surface functionality of its enhanced bactericidal activity against gram positive bacteria

    International Nuclear Information System (INIS)

    Bhuyan, Diganta; Saikia, Mrinal; Saikia, Lakshi; Gogoi, Animesh; Saikia, Ratul

    2015-01-01

    The facile synthesis of an SBA-15-pr- + NH 3 .Au 0 nano-hybrid material by spontaneous autoreduction of aqueous chloroaurate anions on propylamine functionalized SBA-15 was successfully demonstrated. The as-synthesized SBA-15-pr- + NH 3 .Au 0 nano-hybrid material was well characterized using low and wide angle x-ray diffraction (XRD), N 2 adsorption–desorption isotherms, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), x-ray photoelectron spectroscopy (XPS), UV-Visible spectroscopy and atomic absorption spectroscopy (AAS). The activity of the nano-hybrid material as a potent bactericidal agent was successfully tested against Gram positive/negative bacteria viz. Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The colony killing percentage of Gram positive bacteria was found to be higher than Gram negative bacteria due to the stronger electrostatic interaction between the positively-charged amine functionality of SBA-15 and the negatively charged functionality of the bacterial cell wall. (paper)

  12. Biosynthesis of gold nanoparticles by the extreme bacterium Deinococcus radiodurans and an evaluation of their antibacterial properties.

    Science.gov (United States)

    Li, Jiulong; Li, Qinghao; Ma, Xiaoqiong; Tian, Bing; Li, Tao; Yu, Jiangliu; Dai, Shang; Weng, Yulan; Hua, Yuejin

    Deinococcus radiodurans is an extreme bacterium known for its high resistance to stresses including radiation and oxidants. The ability of D. radiodurans to reduce Au(III) and biosynthesize gold nanoparticles (AuNPs) was investigated in aqueous solution by ultraviolet and visible (UV/Vis) absorption spectroscopy, electron microscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). D. radiodurans efficiently synthesized AuNPs from 1 mM Au(III) solution in 8 h. The AuNPs were of spherical, triangular and irregular shapes with an average size of 43.75 nm and a polydispersity index of 0.23 as measured by DLS. AuNPs were distributed in the cell envelope, across the cytosol and in the extracellular space. XRD analysis confirmed the crystallite nature of the AuNPs from the cell supernatant. Data from the FTIR and XPS showed that upon binding to proteins or compounds through interactions with carboxyl, amine, phospho and hydroxyl groups, Au(III) may be reduced to Au(I), and further reduced to Au(0) with the capping groups to stabilize the AuNPs. Biosynthesis of AuNPs was optimized with respect to the initial concentration of gold salt, bacterial growth period, solution pH and temperature. The purified AuNPs exhibited significant antibacterial activity against both Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) bacteria by damaging their cytoplasmic membrane. Therefore, the extreme bacterium D. radiodurans can be used as a novel bacterial candidate for efficient biosynthesis of AuNPs, which exhibited potential in biomedical application as an antibacterial agent.

  13. Isolation and characterization of Halomonas sp. strain C2SS100, a hydrocarbon-degrading bacterium under hypersaline conditions.

    Science.gov (United States)

    Mnif, S; Chamkha, M; Sayadi, S

    2009-09-01

    To isolate and characterize an efficient hydrocarbon-degrading bacterium under hypersaline conditions, from a Tunisian off-shore oil field. Production water collected from 'Sercina' petroleum reservoir, located near the Kerkennah island, Tunisia, was used for the screening of halotolerant or halophilic bacteria able to degrade crude oil. Bacterial strain C2SS100 was isolated after enrichment on crude oil, in the presence of 100 g l(-1) NaCl and at 37 degrees C. This strain was aerobic, Gram-negative, rod-shaped, motile, oxidase + and catalase +. Phenotypic characters and phylogenetic analysis based on the 16S rRNA gene of the isolate C2SS100 showed that it was related to members of the Halomonas genus. The degradation of several compounds present in crude oil was confirmed by GC-MS analysis. The use of refined petroleum products such as diesel fuel and lubricating oil as sole carbon source, under the same conditions of temperature and salinity, showed that significant amounts of these heterogenic compounds could be degraded. Strain C2SS100 was able to degrade hexadecane (C16). During growth on hexadecane, cells surface hydrophobicity and emulsifying activity increased indicating the production of biosurfactant by strain C2SS100. A halotolerant bacterial strain Halomonas sp. C2SS100 was isolated from production water of an oil field, after enrichment on crude oil. This strain is able to degrade hydrocarbons efficiently. The mode of hydrocarbon uptake is realized by the production of a biosurfactant which enhances the solubility of hydrocarbons and renders them more accessible for biodegradation. The biodegradation potential of the Halomonas sp. strain C2SS100 gives it an advantage for possibly application on bioremediation of water, hydrocarbon-contaminated sites under high-salinity level.

  14. Burdock (Arctium lappa Leaf Extracts Increase the In Vitro Antimicrobial Efficacy of Common Antibiotics on Gram-positive and Gram-negative Bacteria

    Directory of Open Access Journals (Sweden)

    Pirvu Lucia

    2017-04-01

    Full Text Available This work aimed to study the potential effects of four Arctii folium extracts, 5 mg gallic [GAE] acid equivalents per 1 mL sample, on six antibiotics (Ampicillin/AM, Tetracycline/TE, Ciprofloxacin/CIP, Sulfamethoxazole-Trimethoprim/SXT, Chloramphenicol/C and Gentamicin/CN tested on four Gram-positive (Staphylococcus aureus ATCC 6538, Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, and Staphylococcus epidermidis ATCC 12228 and five Gram-negative (Proteus mirabilis ATCC 29245, Escherichia coli ATCC 35218, E. coli ATCC 11229, E. coli ATCC 8739, and Bacillus cereus ATCC 11778 bacteria. Arctii folium extracts were the whole ethanol extract/W and subsequent ethyl acetate/EA, aqueous/AQ, and chloroform/CHL fractions. Chemical qualitative analysis (HPTLC method emphasized five main polyphenol compounds in Arctii folium polar extracts: chlorogenic acid (Rf≈0.52/0.55 and its isomer, 1,5-di-O-caffeoylquinic acid (Rf≈0.90/0.92, plus cynarin (Rf≈0.77, hyperoside (Rf≈0.68/0.64 and isoquercitrin (Rf≈0.69/0.71. Microbiological screening indicated Arctii folium polar extracts (AQ and W efficacy on S. epidermidis ATCC 12228; the MIC values were in the range of common antibiotics, being 32 and 128 μg GAE per mL sample respectively. The unpredictable effects (stimulatory or inhibitory of Arctii folium extracts in combination with typical antibiotics as well as a potential use of the whole ethanol extract/W for restoring the antimicrobial potency of susceptible antibiotics have also been evidenced.

  15. Lipids of the ultra-thin square halophilic archaeon Haloquadratum walsbyi

    Directory of Open Access Journals (Sweden)

    Simona LoBasso

    2008-01-01

    Full Text Available The lipid composition of the extremely halophilic archaeon Haloquadratum walsbyi was investigated by thin-layer chromatography and electrospray ionization-mass spectrometry. The analysis of neutral lipids showed the presence of vitamin MK-8, squalene, carotene, bacterioruberin and several retinal isomers. The major polar lipids were phosphatidylglycerophosphate methyl ester, phosphatidylglycerosulfate, phosphatidylglycerol and sulfated diglycosyl diether lipid. Among cardiolipins, the tetra-phytanyl or dimeric phospholipids, only traces of bisphosphatidylglycerol were detected. When the cells were exposed to hypotonic medium, no changes in the membrane lipid composition occurred. Distinguishing it from other extreme halophiles of the Halobacteriaceae family, the osmotic stress did not induce the neo-synthesis of cardiolipins in H. walsbyi. The difference may depend on the three-laminar structure of the cell wall, which differs significantly from that of other Haloarchaea.

  16. Novel Antimicrobial Peptides That Inhibit Gram Positive Bacterial Exotoxin Synthesis

    Science.gov (United States)

    Merriman, Joseph A.; Nemeth, Kimberly A.; Schlievert, Patrick M.

    2014-01-01

    Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and α-globin and β-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized α-globin chain peptides, synthetic variants of α-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges. PMID:24748386

  17. DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea.

    Science.gov (United States)

    Jones, Daniel L; Baxter, Bonnie K

    2017-01-01

    Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV) radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a "first line of defense," and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.

  18. Is the gram stain useful in the microbiologic diagnosis of VAP? A meta-analysis.

    Science.gov (United States)

    O'Horo, John C; Thompson, Deb; Safdar, Nasia

    2012-08-01

    In a meta-analysis examining respiratory specimen Gram stain for diagnosis of ventilator-associated pneumonia, absence of bacteria on Gram stain had a high negative predictive value, but a positive Gram stain correlated poorly with organisms recovered in culture. Rapid and accurate diagnosis of ventilator-associated pneumonia (VAP) is a major challenge and no generally accepted gold standard exists for VAP diagnosis. We conducted a meta-analysis to examine the role of respiratory specimen Gram stain to diagnose VAP, and the correlation with final culture results. In 21 studies, pooled sensitivity of Gram stain for VAP was 0.79 (95% confidence interval [CI], .77-0.81; P Gram stain for a VAP prevalence of 20%-30% was 91%, suggesting that VAP is unlikely with a negative Gram stain but the positive predictive value of Gram stain was only 40%. Pooled kappa was 0.42 for gram-positive organisms and 0.34 for gram-negative organisms, suggesting fair concordance between organisms on Gram stain and recovery by culture. Therefore, a positive Gram stain should not be used to narrow anti-infective therapy until culture results become available.

  19. Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology.

    Science.gov (United States)

    Chuprom, Julalak; Bovornreungroj, Preeyanuch; Ahmad, Mehraj; Kantachote, Duangporn; Dueramae, Sawitree

    2016-06-01

    A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples ( budu ) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett - Burman (PB) experimental design; gelatin, MgSO 4 ·7H 2 O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL).

  20. Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology

    Directory of Open Access Journals (Sweden)

    Julalak Chuprom

    2016-06-01

    Full Text Available A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples (budu and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT approach determined gelatin was the best nitrogen source. Based on Plackett–Burman (PB experimental design; gelatin, MgSO4·7H2O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL was obtained, compared with that produced in the original medium (17.80 U/mL. Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL.

  1. The Role of Functional Amyloids in Multicellular Growth and Development of Gram-Positive Bacteria

    DEFF Research Database (Denmark)

    Dragoš, Anna; Kovács, Ákos T.; Claessen, Dennis

    2017-01-01

    Amyloid fibrils play pivotal roles in all domains of life. In bacteria, these fibrillar structures are often part of an extracellular matrix that surrounds the producing organism and thereby provides protection to harsh environmental conditions. Here, we discuss the role of amyloid fibrils...... in the two distant Gram-positive bacteria, Streptomyces coelicolor and Bacillus subtilis. We describe how amyloid fibrils contribute to a multitude of developmental processes in each of these systems, including multicellular growth and community development. Despite this variety of tasks, we know...... surprisingly little about how their assembly is organized to fulfill all these roles....

  2. Microbacter margulisiae gen. nov., sp. nov., a novel propionigenic bacterium isolated from sediments of an acid rock drainage pond

    NARCIS (Netherlands)

    Sanchez Andrea, I.; Luis Sanz, J.; Stams, A.J.M.

    2014-01-01

    A novel anaerobic propionigenic bacterium, strain ADRIT, was isolated from sediment of an acid rock drainage environment (Tinto River, Spain). Cells were small (0.4-0.6 x 1-1.7 µm), non-motile and non-spore forming rods. Cells possessed a Gram-negative cell wall structure and were vancomycin

  3. Elemental sulfur and thiosulfate disproportionation by Desulfocapsa sulfoexigens sp. nov., a new anaerobic bacterium isolated from marine surface sediment

    DEFF Research Database (Denmark)

    Finster, Kai; Liesack, Werner; Thamdrup, Bo

    1998-01-01

    A mesophilic, anaerobic, gram-negative bacterium, strain SB164P1, was enriched and isolated from oxidized marine surface sediment with elemental sulfur as the sole energy substrate in the presence of ferrihydrite. Elemental sulfur was disproportionated to hydrogen sulfide and sulfate. Growth was ...

  4. Thermincola carboxydiphila gen. nov., sp. nov., a novel anaerobic, carboxydotrophic, hydrogenogenic bacterium from a hot spring of the Lake Baikal area.

    Science.gov (United States)

    Sokolova, Tatyana G; Kostrikina, Nadezhda A; Chernyh, Nikolai A; Kolganova, Tatjana V; Tourova, Tatjana P; Bonch-Osmolovskaya, Elizaveta A

    2005-09-01

    A novel anaerobic, thermophilic, alkalitolerant bacterium, strain 2204(T), was isolated from a hot spring of the Baikal Lake region. The cells of strain 2204(T) were straight rods of variable length, Gram-positive with an S-layer, motile with one to two lateral flagella, and often formed aggregates of 3-15 cells. The isolate was shown to be an obligate anaerobe oxidizing CO and producing equimolar quantities of H(2) and CO(2) according to the equation CO+H(2)O-->CO(2)+H(2). No organic substrates were used as energy sources. For lithotrophic growth on CO, 0.2 g acetate or yeast extract l(-1) was required but did not support growth in the absence of CO. Growth was observed in the temperature range 37-68 degrees C, the optimum being 55 degrees C. The pH range for growth was 6.7-9.5, the optimum pH being 8.0. The generation time under optimal conditions was 1.3 h. The DNA G+C content was 45 mol%. Penicillin, erythromycin, streptomycin, rifampicin, vancomycin and tetracycline completely inhibited both growth and CO utilization by strain 2204(T). Thus, isolate 2204(T) was found to be the first known moderately thermophilic and alkalitolerant H(2)-producing anaerobic carboxydotroph. The novel bacterium fell within the cluster of the family Peptococcaceae within the low-G+C-content Gram-positive bacteria, where it formed a separate branch. On the basis of morphological, physiological and phylogenetic features, strain 2204(T) should be assigned to a novel genus and species, for which the name Thermincola carboxydiphila gen. nov., sp. nov. is proposed. The type strain is strain 2204(T) (=DSM 17129(T)=VKM B-2283(T)=JCM 13258(T)).

  5. Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria

    Science.gov (United States)

    Saavedra, Lucila; Sesma, Fernando

    The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic host systems makes them attractive candidates for biotechnological applications. However, before suggesting or choosing a new bacteriocin for future technology developments, it is necessary to elucidate its biochemical structure and its mode of action, which may be carried out once the bacteriocin is purified to homogeneity. This chapter focuses on describing the main strategies used for the purification of numerous bacteriocins.

  6. Halophilic polysulfabetaines-synthesis and study of gelation and thermoresponsive behavior

    NARCIS (Netherlands)

    Vasantha, Vivek Arjunan; Jana, Satyasankar; Parthiban, Anbanandam; Vancso, Julius G.

    2014-01-01

    Polysulfabetaines (PSBs) derived from zwitterionic sulfates (contrary to commonly used polysulfobetaines which are derived from zwitterionic sulfonates) were synthesized for the first time. PSBs dissolved in brine (halophilic), swelled in deionized water and also exhibited reversible and

  7. Protective role of salt in catalysis and maintaining structure of halophilic proteins against denaturation

    Science.gov (United States)

    Sinha, Rajeshwari; Khare, Sunil K.

    2014-01-01

    Search for new industrial enzymes having novel properties continues to be a desirable pursuit in enzyme research. The halophilic organisms inhabiting under saline/ hypersaline conditions are considered as promising source of useful enzymes. Their enzymes are structurally adapted to perform efficient catalysis under saline environment wherein n0n-halophilic enzymes often lose their structure and activity. Haloenzymes have been documented to be polyextremophilic and withstand high temperature, pH, organic solvents, and chaotropic agents. However, this stability is modulated by salt. Although vast amount of information have been generated on salt mediated protection and structure function relationship in halophilic proteins, their clear understanding and correct perspective still remain incoherent. Furthermore, understanding their protein architecture may give better clue for engineering stable enzymes which can withstand harsh industrial conditions. The article encompasses the current level of understanding about haloadaptations and analyzes structural basis of their enzyme stability against classical denaturants. PMID:24782853

  8. Antibacterial activity of oregano (Origanum vulgare Linn.) against gram positive bacteria.

    Science.gov (United States)

    Saeed, Sabahat; Tariq, Perween

    2009-10-01

    The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium, B. thuringiensis, B. alvei, B. circulans, B. brevis, B. coagulans, B. pumilus, B. laterosporus, B. polymyxa, B. macerans, B. subtilis, B. firmus, B. cereus and B. lichiniformis. The infusion exhibited maximum activity against B. laterosporus (17.5 mm mean zone of inhibition+/-1.5 Standard deviation) followed by B. polymyxa (17.0 mm+/-2.0 SD) and essential oil of oregano exhibited maximum activity against S. saprophyticus (16.8 mm+/-1.8 SD) followed by B. circulans (14.5 mm+/-0.5 SD). While all these tested isolates were found resistant to decoction of oregano.

  9. Comparison of TiO2 and ZnO nanoparticles for photocatalytic degradation of methylene blue and the correlated inactivation of gram-positive and gram-negative bacteria

    International Nuclear Information System (INIS)

    Barnes, Robert J.; Molina, Rodrigo; Xu Jianbin; Dobson, Peter J.; Thompson, Ian P.

    2013-01-01

    Titanium dioxide (TiO 2 ) and zinc oxide (ZnO) nanoparticles are important photocatalysts and as such have been extensively studied for the removal of organic compounds from contaminated air and water and for microbial disinfection. Despite much research on the effect of TiO 2 and ZnO nanoparticles on different bacterial species, uncertainties remain about which bacteria are more sensitive to these compounds. Very few studies have directly compared the toxicity of ZnO to TiO 2 under both light and dark conditions. In addition, authors investigating the photocatalytic inactivation of TiO 2 and ZnO nanoparticles on bacteria have failed to investigate the reactive oxygen species (ROS) generation of the nanoparticles, making it difficult to correlate killing action with the generation of ROS. In this study, three types of metal nanoparticle (ZnO 2 ) have been characterised and ROS production assessed through the degradation of methylene blue (MB). The photocatalytic killing potential of three nanoparticle concentrations (0.01, 0.1 and 1 g/L) was then assessed on four representative bacteria: two gram-positive (S. aureus and B. subtilis) and two gram-negative (E. coli and P. aeruginosa). Results showed that out of the three nanoparticles tested, the TiO 2 nanoparticles generated more ROS than the ZnO nanoparticles, corresponding to a greater photocatalytic inactivation of three of the four species of bacteria examined. The MB decomposition results correlated well with the bacterial inactivation results with higher TiO 2 nanoparticle concentrations leading to greater ROS production and increased loss of cell viability. Although producing less ROS than the TiO 2 nanoparticles under ultraviolet light, the ZnO nanoparticles were toxic to two of the bacterial species even under dark conditions. In this study, no correlation between cell wall type and bacterial inactivation was observed for any of the nanoparticles tested although both gram-positive bacteria were sensitive to

  10. [Usefulness of sputum Gram staining in community-acquired pneumonia].

    Science.gov (United States)

    Sato, Tadashi; Aoshima, Masahiro; Ohmagari, Norio; Tada, Hiroshi; Chohnabayashi, Naohiko

    2002-07-01

    To evaluate the usefulness of sputum gram staining in community-acquired pneumonia (CAP), we reviewed 144 cases requiring hospitalization in the last 4 years. The sensitivity was 75.5%, specificity 68.2%, positive predictive value 74.1%, negative predictive value 69.8%, positive likelihood ratio 2.37, negative likelihood ratio 0.36 and accuracy 72.2% in 97 cases. Both sputum gram staining and culture were performed. Concerning bacterial pneumonia (65 cases), we compared the Gram staining group (n = 33), which received initial antibiotic treatment, based on sputum gram staining with the Empiric group (n = 32) that received antibiotics empirically. The success rates of the initial antibiotic treatment were 87.9% vs. 78.1% (P = 0.473); mean hospitalization periods were 9.67 vs. 11.75 days (P = 0.053); and periods of intravenous therapy were 6.73 vs. 7.91 days (P = 0.044), respectively. As for initial treatment, penicillins were used in the Gram staining group more frequently (P gram staining is useful for the shortening of the treatment period and the appropriate selection of initial antibiotics in bacterial pneumonia. We believe, therefore, that sputum gram staining is indispensable as a diagnostic tool CAP.

  11. Chemical composition and antimicrobial activity of the essential oil of the leaves of Feronia elephantum (Rutaceae) from north west Karnataka.

    Science.gov (United States)

    Joshi, Rajesh K; Badakar, Vijayalaxmi M; Kholkute, Sanjiva D; Khatib, Nayeem

    2011-01-01

    The essential oil of the leaves of Feronia elephantum Corr. was analyzed by gas chromatography and gas chromatography/mass spectrometry. The main constituents were beta-pinene (28.4%), Z-anethole (22.1%), methyl chavicol (12.0%) and E-anethole (8.1%), among thirty-three identified compounds, which represented 92.6% of the total oil. The antimicrobial activity was tested against five Gram-positive and eight Gram-negative bacteria, and four fungi. The oil was active against Micrococcus luteus (Gram-positive bacterium), Proteus mirabilis (Gram-negative bacterium), Penicillium chrysogenum and Aspergillus niger (fungi) with MIC values of 0.31 +/- 0.06, 0.52 +/- 0.10, 0.20 +/- 0.50 and 0.26 +/- 0.52 mg/mL, respectively.

  12. A new technique for Gram staining paraffin-embedded tissue.

    Science.gov (United States)

    Engbaek, K; Johansen, K S; Jensen, M E

    1979-01-01

    Five techniques for Gram staining bacteria in paraffin sections were compared on serial sections of pulmonary tissues from eight bacteriological necropsies. Brown and Hopp's method was the most satisfactory for distinguishing Gram-positive and Gram-negative bacteria. However, this method cannot be recommended as the preparations were frequently overstained, and the Gram-negative bacteria were stained indistinctly. A modification of Brown and Hopps' method was developed which stains larger numbers of Gram-negative bacteria and differentiates well between different cell types and connective tissue, and there is no risk of overstaining. PMID:86548

  13. The optimization and validation of the Biotyper MALDI-TOF MS database for the identification of Gram-positive anaerobic cocci

    NARCIS (Netherlands)

    Veloo, A. C. M.; de Vries, E D; Jean-Pierre, H.; Justesen, U. S.; Morris, T.; Urban, E.; Wybo, I.; van Winkelhoff, A. J.

    OBJECTIVES: Gram-positive anaerobic cocci (GPAC) account for 24-31% of the anaerobic bacteria isolated from human clinical specimens. At present GPAC are underrepresented in the Biotyper MALDI-TOF MS database. Profiles of new species have yet to be added. We present the optimization of the MALDI-TOF

  14. Complete genome sequence of Klebsiella pneumoniae J1, a protein-based microbial flocculant-producing bacterium.

    Science.gov (United States)

    Pang, Changlong; Li, Ang; Cui, Di; Yang, Jixian; Ma, Fang; Guo, Haijuan

    2016-02-20

    Klebsiella pneumoniae J1 is a Gram-negative strain, which belongs to a protein-based microbial flocculant-producing bacterium. However, little genetic information is known about this species. Here we carried out a whole-genome sequence analysis of this strain and report the complete genome sequence of this organism and its genetic basis for carbohydrate metabolism, capsule biosynthesis and transport system. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea

    Directory of Open Access Journals (Sweden)

    Daniel L. Jones

    2017-09-01

    Full Text Available Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a “first line of defense,” and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.

  16. Synergistic effect of Carum copticum and Mentha piperita essential oils with ciprofloxacin, vancomycin, and gentamicin on Gram-negative and Gram-positive bacteria

    Science.gov (United States)

    Talei, Gholam-Reza; Mohammadi, Mohsen; Bahmani, Mahmoud; Kopaei, Mahmoud Rafieian

    2017-01-01

    Background: Infectious diseases have always been an important health issue in human communities. In the recent years, much research has been conducted on antimicrobial effects of nature-based compounds because of increased prevalence of antibiotic resistance. The present study was conducted to investigate synergistic effect of Carum copticum and Mentha piperita essential oils with ciprofloxacin, vancomycin, and gentamicin on Gram-negative and Gram-positive bacteria. Materials and Methods: In this experimental study, the synergistic effects of C. copticum and M. piperita essential oils with antibiotics on Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Staphylococcus epidermidis (ATCC 14990), and Listeria monocytogenes (ATCC 7644) were studied according to broth microdilution and the MIC and fractional inhibitory concentration (FIC) of these two essential oils determined. Results: C. copticum essential oil at 30 μg/ml could inhibit S. aureus, and in combination with vancomycin, decreased MIC from 0.5 to 0.12 μg/ml. Moreover, the FIC was derived 0.24 μg/ml which represents a potent synergistic effect with vancomycin against S. aureus growth. C. copticum essential oil alone or combined with other antibiotics is effective in treating bacterial infections. Conclusions: In addition, C. copticum essential oil can strengthen the activities of certain antibiotics, which makes it possible to use this essential oil, especially in drug resistance or to lower dosage or toxicity of the drugs. PMID:28929050

  17. Compatible Solute Synthesis and Import by the Moderate Halophile Spiribacter salinus: Physiology and Genomics

    Directory of Open Access Journals (Sweden)

    María J. León

    2018-02-01

    Full Text Available Members of the genus Spiribacter are found worldwide and are abundant in ecosystems possessing intermediate salinities between seawater and saturated salt concentrations. Spiribacter salinus M19-40 is the type species of this genus and its first cultivated representative. In the habitats of S. salinus M19-40, high salinity is a key determinant for growth and we therefore focused on the cellular adjustment strategy to this persistent environmental challenge. We coupled these experimental studies to the in silico mining of the genome sequence of this moderate halophile with respect to systems allowing this bacterium to control its potassium and sodium pools, and its ability to import and synthesize compatible solutes. S. salinus M19-40 produces enhanced levels of the compatible solute ectoine, both under optimal and growth-challenging salt concentrations, but the genes encoding the corresponding biosynthetic enzymes are not organized in a canonical ectABC operon. Instead, they are scrambled (ectAC; ectB and are physically separated from each other on the S. salinus M19-40 genome. Genomes of many phylogenetically related bacteria also exhibit a non-canonical organization of the ect genes. S. salinus M19-40 also synthesizes trehalose, but this compatible solute seems to make only a minor contribution to the cytoplasmic solute pool under osmotic stress conditions. However, its cellular levels increase substantially in stationary phase cells grown under optimal salt concentrations. In silico genome mining revealed that S. salinus M19-40 possesses different types of uptake systems for compatible solutes. Among the set of compatible solutes tested in an osmostress protection growth assay, glycine betaine and arsenobetaine were the most effective. Transport studies with radiolabeled glycine betaine showed that S. salinus M19-40 increases the pool size of this osmolyte in a fashion that is sensitively tied to the prevalent salinity of the growth medium

  18. Reconstitution of Protein Translation of Mycobacterium Reveals Functional Conservation and Divergence with the Gram-Negative Bacterium Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Aashish Srivastava

    Full Text Available Protein translation is essential for all bacteria pathogens. It has also been a major focus of structural and functional studies and an important target of antibiotics. Here we report our attempts to biochemically reconstitute mycobacterial protein translation in vitro from purified components. This mycobacterial translation system consists of individually purified recombinant translation factors from Mycobacterium tuberculosis (M. tuberculosis, purified tRNAs and ribosomes from Mycobacterium smegmatis (M. smegmatis, and an aminoacyl-tRNA synthetase (AARS mixture from the cell-extract of M. smegmatis. We demonstrate that such mycobacterial translation system was efficient in in vitro protein synthesis, and enabled functional comparisons of translational components between the gram-positive Mycobacterium and the gram-negative E. coli. Although mycobacterial translation factors and ribosomes were highly compatible with their E. coli counterparts, M. smegmatis tRNAs were not properly charged by the E. coli AARSs to allow efficient translation of a reporter. In contrast, both E. coli and M. smegmatis tRNAs exhibited similar activity with the semi-purified M. smegmatis AARSs mixture for in vitro translation. We further demonstrated the use of both mycobacterial and E. coli translation systems as comparative in vitro assays for small-molecule antibiotics that target protein translation. While mycobacterial and E. coli translation were both inhibited at the same IC50 by the antibiotic spectinomycin, mycobacterial translation was preferentially inhibited by the antibiotic tetracycline, suggesting that there may be structural differences at the antibiotic binding sites between the ribosomes of Mycobacterium and E. coli. Our results illustrate an alternative approach for antibiotic discovery and functional studies of protein translation in mycobacteria and possibly other bacterial pathogens.

  19. Competitive binding of polyethyleneimine-coated gold nanoparticles to enzymes and bacteria: a key mechanism for low-level colorimetric detection of gram-positive and gram-negative bacteria

    International Nuclear Information System (INIS)

    Thiramanas, Raweewan; Laocharoensuk, Rawiwan

    2016-01-01

    The article describes a simple and rapid method for colorimetric detection of bacteria. It is based on competitive binding of positively charged polyethyleneimine-coated gold nanoparticles (PEI-AuNPs) to negatively charged enzymes and bacteria. The PEI-AuNPs are electrostatically attracted by both the bacterial surface and the enzyme β-galactosidase (β-Gal). Binding to the latter results in the inhibition of enzyme activity. However, in the presence of a large number of bacteria, the PEI-AuNPs preferentially bind to bacteria. Hence, the enzyme will not be inhibited and its activity can be colorimetrically determined via hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside (CPRG). The detection limit of this assay is as low as 10 cfu·mL −1 , and the linear range extends from 10 6 to 10 8 cfu·mL −1 . The assay is applicable to both Gram-negative (such as enterotoxigenic Escherichia coli; ETEC) and Gram-positive (Staphylococcus aureus; S. aureus) bacteria. Results are obtained within 10 min using an optical reader, and within 2–3 h by bare-eye detection. The method was applied to the identification of ETEC contamination at a level of 10 cfu·mL −1 in spiked drinking water. Given its low detection limit and rapidity (sample preconcentration is not required), this method holds great promise for on-site detection of total bacterial contamination. (author)

  20. Biomineralization of carbonate and phosphate by moderately halophilic bacteria

    NARCIS (Netherlands)

    Sánchez-Román, Mónica; Rivadeneyra, Maria A.; Vasconcelos, Crisogono; McKenzie, Judith A.

    We investigated the precipitation of carbonate and phosphate minerals by 19 species of moderately halophilic bacteria using media with variable Mg 2+/Ca2+ ratios. The precipitated minerals were calcite, magnesium (Mg) calcite, and struvite (MgNH4PO4· 6H2O) in variable proportions depending on the

  1. EFFECT OF SILICATE ON GRAM STAINING AND VIABILITY OF PNEUMOCOCCI AND OTHER BACTERIA

    Science.gov (United States)

    MacLeod, Colin M.; Roe, Amy S.

    1956-01-01

    Application of silicate solutions to living or heat-killed pneumococci and to certain "viridans" streptococci causes their conversion from a Gram-positive to a Gram-negative state. The original staining properties can be restored by suspending the silicate-treated bacteria in alkaline solutions of various salts but not by simple washing in water. Living pneumococci and the strains of streptococci whose staining properties are similarly affected are killed when suspended in silicate solutions. In other Gram-positive species silicate causes conversion to Gram negativity but restoration to positivity occurs upon washing in water. In a third group of Gram-positive organisms silicate has no effect on the Gram reaction. The viability of organisms in these two groups is unaffected by silicate under the conditions employed. No effect on staining or viability of Gram-negative bacteria has been observed. The effects of silicate on staining and viability are inhibited by nutrient broth or whole serum but not by purified serum albumin. Lecithin, choline, and other substituted ammonium compounds also inhibit the effects of silicate on pneumococci. PMID:13306854

  2. Diversity of halophilic archaea from six hypersaline environments in Turkey.

    Science.gov (United States)

    Ozcan, Birgul; Ozcengiz, Gulay; Coleri, Arzu; Cokmus, Cumhur

    2007-06-01

    The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

  3. Diverse antimicrobial interactions of halophilic archaea and bacteria extend over geographical distances and cross the domain barrier.

    Science.gov (United States)

    Atanasova, Nina S; Pietilä, Maija K; Oksanen, Hanna M

    2013-10-01

    The significance of antimicrobial substances, halocins, produced by halophilic archaea and bacteria thriving in hypersaline environments is relatively unknown. It is suggested that their production might increase species diversity and give transient competitive advances to the producer strain. Halocin production is considered to be common among halophilic archaea, but there is a lack of information about halocins produced by bacteria in highly saline environments. We studied the antimicrobial activity of 68 halophilic archaea and 22 bacteria isolated from numerous geographically distant hypersaline environments. Altogether 144 antimicrobial interactions were found between the strains and aside haloarchaea, halophilic bacteria from various genera were identified as halocin producers. Close to 80% of the interactions were detected between microorganisms from different genera and in few cases, even across the domain boundary. Several of the strains produced halocins with a wide inhibitory spectrum as has been observed before. Most of the antimicrobial interactions were found between strains from distant sampling sites indicating that hypersaline environments around the world have similar microorganisms with the potential to produce wide activity range antimicrobials. © 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  4. Isolation and characterization of a radiation resistant thermophilic bacterium from radon hot spring

    International Nuclear Information System (INIS)

    Liang Xinle; Yang Long; Zhang Hong; Zhang Lei

    2011-01-01

    A radiation resistant and thermophilic bacterium strain R4-33 was isolated from radon hot spring water samples, pretreated with 60 Co γ-rays and UV irradiation. Tests on morphological, physiological and biochemical characters, fatty acid compositions, (G + C) mol% contents, and 16S rDNA sequencing were conducted. The results showed that strain R4-33 was of rod-shape, Gram-negative, atrichous, and endospore-forming. The optimum growth temperature and pH were 60 ℃ and 7.5, respectively. The strain utilized glucose, maltose and trehalose as carbon sources, and hydrolyzed casein and starch. Its catalase positive. The strain was sensitive to penicillin, neomycin, erythromycin, vancomycin, streptomycin, gentamycin, amikacin and ampicillin. The major cellular fatty acids were C 14:1 (48.8%) and C 15:1 (15.2%). The (G + C) mol% content of DNA was 58.2%. Phylogenetic tree based on 16S rDNA sequence showed R4-33 shared highly similarity to those of species in genus Anoxybacillus, especially to that of Anoxybacillus gonensis (99.5%). Based on the above, the strain R4-33 was proposed to the evolution branch of Anoxybacillus and designated as Anoxybacillu sp. R4-33. The UV and γ-radiation tests showed that the strain R4-33 had an ability of resistance to UV of 396 J/m 2 and 60 Co γ-rays irradiation of 14.0 kGy, indicating that the strain was a radiation resistant and thermophilic bacterium. (authors)

  5. Overcoming function annotation errors in the Gram-positive pathogen Streptococcus suis by a proteomics-driven approach

    Directory of Open Access Journals (Sweden)

    Bárcena José A

    2008-12-01

    Full Text Available Abstract Background Annotation of protein-coding genes is a key step in sequencing projects. Protein functions are mainly assigned on the basis of the amino acid sequence alone by searching of homologous proteins. However, fully automated annotation processes often lead to wrong prediction of protein functions, and therefore time-intensive manual curation is often essential. Here we describe a fast and reliable way to correct function annotation in sequencing projects, focusing on surface proteomes. We use a proteomics approach, previously proven to be very powerful for identifying new vaccine candidates against Gram-positive pathogens. It consists of shaving the surface of intact cells with two proteases, the specific cleavage-site trypsin and the unspecific proteinase K, followed by LC/MS/MS analysis of the resulting peptides. The identified proteins are contrasted by computational analysis and their sequences are inspected to correct possible errors in function prediction. Results When applied to the zoonotic pathogen Streptococcus suis, of which two strains have been recently sequenced and annotated, we identified a set of surface proteins without cytoplasmic contamination: all the proteins identified had exporting or retention signals towards the outside and/or the cell surface, and viability of protease-treated cells was not affected. The combination of both experimental evidences and computational methods allowed us to determine that two of these proteins are putative extracellular new adhesins that had been previously attributed a wrong cytoplasmic function. One of them is a putative component of the pilus of this bacterium. Conclusion We illustrate the complementary nature of laboratory-based and computational methods to examine in concert the localization of a set of proteins in the cell, and demonstrate the utility of this proteomics-based strategy to experimentally correct function annotation errors in sequencing projects. This

  6. Problems in identification of Francisella philomiragia associated with fatal bacteremia in a patient with chronic granulomatous disease

    DEFF Research Database (Denmark)

    Friis-Møller, Alice; Lemming, L E; Valerius, Niels Henrik

    2004-01-01

    Francisella philomiragia is a rare gram-negative, halophilic coccobacillus with bizarre spherical forms on primary isolation. A case of F. philomiragia bacteremia in a 24-year-old patient with chronic granulomatous disease is reported. Identification of F. philomiragia was problematic with conven......Francisella philomiragia is a rare gram-negative, halophilic coccobacillus with bizarre spherical forms on primary isolation. A case of F. philomiragia bacteremia in a 24-year-old patient with chronic granulomatous disease is reported. Identification of F. philomiragia was problematic...

  7. Characterization of Halophilic Bacterial Communities in Turda Salt Mine (Romania)

    Science.gov (United States)

    Carpa, Rahela; Keul, Anca; Muntean, Vasile; Dobrotă, Cristina

    2014-09-01

    Halophilic organisms are having adaptations to extreme salinity, the majority of them being Archaean, which have the ability to grow at extremely high salt concentrations, (from 3 % to 35 %). Level of salinity causes natural fluctuations in the halophilic populations that inhabit this particular habitat, raising problems in maintaining homeostasis of the osmotic pressure. Samples such as salt and water taken from Turda Salt Mine were analyzed in order to identify the eco-physiological bacterial groups. Considering the number of bacteria of each eco-physiological group, the bacterial indicators of salt quality (BISQ) were calculated and studied for each sample. The phosphatase, catalase and dehydrogenases enzymatic activities were quantitatively determined and the enzymatic indicators of salt quality (EISQ) were calculated. Bacterial isolates were analyzed using 16S rRNA gene sequence analysis. Universal bacterial primers, targeting the consensus region of the bacterial 16S rRNA gene were used. Analysis of a large fragment, of 1499 bp was performed to improve discrimination at the species level.

  8. Decreased mortality associated with prompt Gram staining of blood cultures.

    Science.gov (United States)

    Barenfanger, Joan; Graham, Donald R; Kolluri, Lavanya; Sangwan, Gaurav; Lawhorn, Jerry; Drake, Cheryl A; Verhulst, Steven J; Peterson, Ryan; Moja, Lauren B; Ertmoed, Matthew M; Moja, Ashley B; Shevlin, Douglas W; Vautrain, Robert; Callahan, Charles D

    2008-12-01

    Gram stains of positive blood cultures are the most important factor influencing appropriate therapy. The sooner appropriate therapy is initiated, the better. Therefore, it is reasonable to expect that the sooner Gram stains are performed, the better. To determine the value of timely Gram stains and whether improvement in Gram stain turnaround time (TAT) is feasible, we compared data for matched pairs of patients with cultures processed promptly ( or =1 hour TAT) and then monitored TAT by control charting.In 99 matched pairs, average difference in time to detection of positive blood cultures within a pair of patients was less than 0.1 hour. For the less than 1 hour TAT group, the average TAT and crude mortality were 0.1 hour and 10.1%, respectively; for the 1 hour or longer TAT group, they were 3.3 hours and 19.2%, respectively (P Gram stains.

  9. Should gram stains have a role in diagnosing hip arthroplasty infections?

    Science.gov (United States)

    Johnson, Aaron J; Zywiel, Michael G; Stroh, D Alex; Marker, David R; Mont, Michael A

    2010-09-01

    The utility of Gram stains in diagnosing periprosthetic infections following total hip arthroplasty has recently been questioned. Several studies report low sensitivity of the test, and its poor ability to either confirm or rule out infection in patients undergoing revision total hip arthroplasty. Despite this, many institutions including that of the senior author continue to perform Gram stains during revision total hip arthroplasty. We assessed the sensitivity, specificity, accuracy, and positive and negative predictive values of Gram stains from surgical-site samplings taken from procedures on patients with both infected and aseptic revision total hip arthroplasties. A review was performed on patients who underwent revision total hip arthroplasty between 2000 and 2007. Eighty-two Gram stains were performed on patients who had infected total hip arthroplasties and underwent revision procedures. Additionally, of the 410 revision total hip arthroplasties performed on patients who were confirmed infection-free, 120 Gram stains were performed. Patients were diagnosed as infected using multiple criteria at the time of surgery. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated from these Gram stain results. The Gram stain demonstrated a sensitivity and specificity of 9.8% and 100%, respectively. In this series, the Gram stain had a negative predictive value of 62%, a positive predictive value of 100%, and an accuracy of 63%. Gram stains obtained from surgical-site samples had poor sensitivity and poor negative predictive value. Based on these findings, as well as those of other authors, we believe that Gram stains should no longer be considered for diagnosing infections in revision total hip arthroplasty. Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

  10. The potent antimicrobial properties of cell penetrating peptide-conjugated silver nanoparticles with excellent selectivity for gram-positive bacteria over erythrocytes.

    Science.gov (United States)

    Liu, Lihong; Yang, Jun; Xie, Jianping; Luo, Zhentao; Jiang, Jiang; Yang, Yi Yan; Liu, Shaomin

    2013-05-07

    Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (gram-positive Bacillus subtilis, gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects.

  11. An unusual class of anthracyclines potentiate Gram-positive antibiotics in intrinsically resistant Gram-negative bacteria

    Science.gov (United States)

    Cox, Georgina; Koteva, Kalinka; Wright, Gerard D.

    2014-01-01

    Objectives An orthogonal approach taken towards novel antibacterial drug discovery involves the identification of small molecules that potentiate or enhance the activity of existing antibacterial agents. This study aimed to identify natural-product rifampicin adjuvants in the intrinsically resistant organism Escherichia coli. Methods E. coli BW25113 was screened against 1120 actinomycete fermentation extracts in the presence of subinhibitory (2 mg/L) concentrations of rifampicin. The active molecule exhibiting the greatest rifampicin potentiation was isolated using activity-guided methods and identified using mass and NMR spectroscopy. Susceptibility testing and biochemical assays were used to determine the mechanism of antibiotic potentiation. Results The anthracycline Antibiotic 301A1 was isolated from the fermentation broth of a strain of Streptomyces (WAC450); the molecule was shown to be highly synergistic with rifampicin (fractional inhibitory concentration index = 0.156) and moderately synergistic with linezolid (FIC index = 0.25) in both E. coli and Acinetobacter baumannii. Activity was associated with inhibition of efflux and the synergistic phenotype was lost when tested against E. coli harbouring mutations within the rpoB gene. Structure–activity relationship studies revealed that other anthracyclines do not synergize with rifampicin and removal of the sugar moiety of Antibiotic 301A1 abolishes activity. Conclusions Screening only a subsection of our natural product library identified a small-molecule antibiotic adjuvant capable of sensitizing Gram-negative bacteria to antibiotics to which they are ordinarily intrinsically resistant. This result demonstrates the great potential of this approach in expanding antibiotic effectiveness in the face of the growing challenge of resistance in Gram-negatives. PMID:24627312

  12. Cues and regulatory pathways involved in natural competence and transformation in pathogenic and environmental Gram-negative bacteria.

    Science.gov (United States)

    Seitz, Patrick; Blokesch, Melanie

    2013-05-01

    Bacterial genomics is flourishing, as whole-genome sequencing has become affordable, readily available and rapid. As a result, it has become clear how frequently horizontal gene transfer (HGT) occurs in bacteria. The potential implications are highly significant because HGT contributes to several processes, including the spread of antibiotic-resistance cassettes, the distribution of toxin-encoding phages and the transfer of pathogenicity islands. Three modes of HGT are recognized in bacteria: conjugation, transduction and natural transformation. In contrast to the first two mechanisms, natural competence for transformation does not rely on mobile genetic elements but is driven solely by a developmental programme in the acceptor bacterium. Once the bacterium becomes competent, it is able to take up DNA from the environment and to incorporate the newly acquired DNA into its own chromosome. The initiation and duration of competence differ significantly among bacteria. In this review, we outline the latest data on representative naturally transformable Gram-negative bacteria and how their competence windows differ. We also summarize how environmental cues contribute to the initiation of competence in a subset of naturally transformable Gram-negative bacteria and how the complexity of the niche might dictate the fine-tuning of the competence window. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  13. Recovery of vancomycin-resistant gram-positive cocci from children.

    Science.gov (United States)

    Green, M; Wadowsky, R M; Barbadora, K

    1990-03-01

    A cross-sectional survey of vancomycin-resistant gram-positive cocci (VRGPC) in the feces of children was initiated after several bacteremic infections with these organisms occurred at our hospital. A selective medium consisting of colistin-nalidixic acid agar, 5% sheep blood, vancomycin (5 mg/liter), and amphotericin B (8 mg/liter) was developed to isolate VRGPC. A single stool specimen submitted to the clinical microbiology laboratory from each of 48 patients was inoculated onto the medium. Plates were incubated at 35 degrees C with 5% carbon dioxide and examined at 24, 48, and 72 h. Susceptibilities were determined by broth microdilution. A total of 14 isolates from 11 of 48 (22%) children were recovered. The density of growth ranged from a single colony to 2+. The VRGPC were identified as Leuconostoc lactis (n = 2), Lactobacillus confusus (n = 4), Enterococcus species (n = 5), and Lactococcus lactis (n = 3). One strain of Lactobacillus confusus was recovered from both the stool and the blood of one of these patients. The MICs of vancomycin were 4 micrograms/ml for one of the isolates, 8 micrograms/ml for four of the isolates, and more than 16 micrograms/ml for the remaining eight isolates. All isolates were susceptible to both penicillin and ampicillin. Only 1 of the 11 children had received prior treatment with vancomycin. We conclude that low concentrations of VRGPC may be common in the gastrointestinal tracts of children.

  14. Curative Treatment of Severe Gram-Negative Bacterial Infections by a New Class of Antibiotics Targeting LpxC

    Directory of Open Access Journals (Sweden)

    Nadine Lemaître

    2017-07-01

    Full Text Available The infectious diseases caused by multidrug-resistant bacteria pose serious threats to humankind. It has been suggested that an antibiotic targeting LpxC of the lipid A biosynthetic pathway in Gram-negative bacteria is a promising strategy for curing Gram-negative bacterial infections. However, experimental proof of this concept is lacking. Here, we describe our discovery and characterization of a biphenylacetylene-based inhibitor of LpxC, an essential enzyme in the biosynthesis of the lipid A component of the outer membrane of Gram-negative bacteria. The compound LPC-069 has no known adverse effects in mice and is effective in vitro against a broad panel of Gram-negative clinical isolates, including several multiresistant and extremely drug-resistant strains involved in nosocomial infections. Furthermore, LPC-069 is curative in a murine model of one of the most severe human diseases, bubonic plague, which is caused by the Gram-negative bacterium Yersinia pestis. Our results demonstrate the safety and efficacy of LpxC inhibitors as a new class of antibiotic against fatal infections caused by extremely virulent pathogens. The present findings also highlight the potential of LpxC inhibitors for clinical development as therapeutics for infections caused by multidrug-resistant bacteria.

  15. Reversible Activation of Halophilic β-lactamase from Methanol-Induced Inactive Form: Contrast to Irreversible Inactivation of Non-Halophilic Counterpart.

    Science.gov (United States)

    Tokunaga, Hiroko; Maeda, Junpei; Arakawa, Tsutomu; Tokunaga, Masao

    2017-06-01

    Effects of a water-miscible organic solvent, methanol, on the structure and activity of halophilic β-lactamase derived from Chromohalobacter sp.560 (HaBla), were investigated by means of circular dichroism (CD) measurement and enzymatic activity determination. Beta-lactamase activity was enhanced about 1.2-fold in the presence of 10-20% methanol. CD measurement of HaBla revealed different structures depending on the methanol concentration: native-like active form (Form I) in 10-20% methanol and methanol-induced inactive form at higher concentration (Form II in 40-60% and Form III in 75-80% methanol). Incubation of HaBla with 40% methanol led to the complete loss of activity within ~80 min accompanied by the formation of Form II, whose activity was recovered promptly up to ~80% of full activity upon dilution of the methanol concentration to 10%. In addition, when the protein concentration was sufficiently high (e.g., 0.7 mg/ml), HaBla activity of Form III in 75% methanol could be recovered in the same way (with slightly slower recovery rate), upon dilution of the methanol concentration. In contrast, non-halophilic β-lactamase from Escherichia coli K12 strain MG1655 (EcBla) was irreversibly denatured in the presence of 40% methanol. HaBla showed remarkable ability to renature from the methanol-induced inactive states.

  16. Chemical analysis of isolated cell walls of Gram-positive bacteria and the determination of the cell wall to cell mass ratio.

    NARCIS (Netherlands)

    Wal, van der A.; Norde, W.; Bendinger, B.; Zehnder, A.J.B.; Lyklema, J.

    1997-01-01

    Cell walls of five Gram-positive bacterial strains, including four coryneforms and a Bacillus brevis strain were isolated and subsequently chemically analysed. The wall contribution to the total cell mass is calculated from a comparison of D-Lactate concentrations in hydrolysates of whole cells and

  17. Analysis of metagenomic data reveals common features of halophilic viral communities across continents.

    Science.gov (United States)

    Roux, Simon; Enault, Francois; Ravet, Viviane; Colombet, Jonathan; Bettarel, Yvan; Auguet, Jean-Christophe; Bouvier, Thierry; Lucas-Staat, Soizick; Vellet, Agnès; Prangishvili, David; Forterre, Patrick; Debroas, Didier; Sime-Ngando, Telesphore

    2016-03-01

    Microbial communities from hypersaline ponds, dominated by halophilic archaea, are considered specific of such extreme conditions. The associated viral communities have accordingly been shown to display specific features, such as similar morphologies among different sites. However, little is known about the genetic diversity of these halophilic viral communities across the Earth. Here, we studied viral communities in hypersaline ponds sampled on the coast of Senegal (8-36% of salinity) using metagenomics approach, and compared them with hypersaline viromes from Australia and Spain. The specificity of hyperhalophilic viruses could first be demonstrated at a community scale, salinity being a strong discriminating factor between communities. For the major viral group detected in all samples (Caudovirales), only a limited number of halophilic Caudovirales clades were highlighted. These clades gather viruses from different continents and display consistent genetic composition, indicating that they represent related lineages with a worldwide distribution. Non-tailed hyperhalophilic viruses display a greater rate of gene transfer and recombination, with uncharacterized genes conserved across different kind of viruses and plasmids. Thus, hypersaline viral communities around the world appear to form a genetically consistent community that are likely to harbour new genes coding for enzymes specifically adapted to these environments. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Design, Synthesis and Evaluation of Branched RRWQWR-Based Peptides as Antibacterial Agents Against Clinically Relevant Gram-Positive and Gram-Negative Pathogens

    Directory of Open Access Journals (Sweden)

    Sandra C. Vega

    2018-03-01

    Full Text Available Multidrug resistance of pathogenic bacteria has become a public health crisis that requires the urgent design of new antibacterial drugs such as antimicrobial peptides (AMPs. Seeking to obtain new, lactoferricin B (LfcinB-based synthetic peptides as viable early-stage candidates for future development as AMPs against clinically relevant bacteria, we designed, synthesized and screened three new cationic peptides derived from bovine LfcinB. These peptides contain at least one RRWQWR motif and differ by the copy number (monomeric, dimeric or tetrameric and structure (linear or branched of this motif. They comprise a linear palindromic peptide (RWQWRWQWR, a dimeric peptide (RRWQWR2KAhx and a tetrameric peptide (RRWQWR4K2Ahx2C2. They were screened for antibacterial activity against Enterococcus faecalis (ATCC 29212 and ATCC 51575 strains, Pseudomonas aeruginosa (ATCC 10145 and ATCC 27853 strains and clinical isolates of two Gram-positive bacteria (Enterococcus faecium and Staphylococcus aureus and two Gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa. All three peptides exhibited greater activity than did the reference peptide, LfcinB (17–31, which contains a single linear RRWQWR motif. Against the ATCC reference strains, the three new peptides exhibited minimum inhibitory concentration (MIC50 values of 3.1–198.0 μM and minimum bactericidal concentration (MBC values of 25–200 μM, and against the clinical isolates, MIC50 values of 1.6–75.0 μM and MBC values of 12.5–100 μM. However, the tetrameric peptide was also found to be strongly hemolytic (49.1% at 100 μM. Scanning Electron Microscopy (SEM demonstrated that in the dimeric and tetrameric peptides, the RRWQWR motif is exposed to the pathogen surface. Our results may inform the design of new, RRWQWR-based AMPs.

  19. Evolution of Recognition of Ligands from Gram-Positive Bacteria: Similarities and Differences in the TLR2-Mediated Response between Mammalian Vertebrates and Teleost Fish

    NARCIS (Netherlands)

    Ribeiro, Carla M. S.; Hermsen, Trudi; Taverne-Thiele, Anja J.; Savelkoul, Huub F. J.; Wiegertjes, Geert F.

    2010-01-01

    We investigated the role of the TLR2 receptor in the recognition of ligands from Gram-positive bacteria in fish. Comparative sequence analysis showed a highly conserved Toll/IL-1 receptor domain. Although the leucine-rich repeat domain was less conserved, the position of the critical peptidoglycan

  20. Molecular interactions within the halophilic, thermophilic, and mesophilic prokaryotic ribosomal complexes: clues to environmental adaptation.

    Science.gov (United States)

    Mallik, Saurav; Kundu, Sudip

    2015-01-01

    Using the available crystal structures of 50S ribosomal subunits from three prokaryotic species: Escherichia coli (mesophilic), Thermus thermophilus (thermophilic), and Haloarcula marismortui (halophilic), we have analyzed different structural features of ribosomal RNAs (rRNAs), proteins, and of their interfaces. We have correlated these structural features with the environmental adaptation strategies of the corresponding species. While dense intra-rRNA packing is observed in thermophilic, loose intra-rRNA packing is observed in halophilic (both compared to mesophilic). Interestingly, protein-rRNA interfaces of both the extremophiles are densely packed compared to that of the mesophilic. The intersubunit bridge regions are almost devoid of cavities, probably ensuring the proper formation of each bridge (by not allowing any loosely packed region nearby). During rRNA binding, the ribosomal proteins experience some structural transitions. Here, we have analyzed the intrinsically disordered and ordered regions of the ribosomal proteins, which are subjected to such transitions. The intrinsically disordered and disorder-to-order transition sites of the thermophilic and mesophilic ribosomal proteins are simultaneously (i) highly conserved and (ii) slowly evolving compared to rest of the protein structure. Although high conservation is observed at such sites of halophilic ribosomal proteins, but slow rate of evolution is absent. Such differences between thermophilic, mesophilic, and halophilic can be explained from their environmental adaptation strategy. Interestingly, a universal biophysical principle evident by a linear relationship between the free energy of interface formation, interface area, and structural changes of r-proteins during assembly is always maintained, irrespective of the environmental conditions.

  1. Use of the Lactococcal nisA Promoter To Regulate Gene Expression in Gram-Positive Bacteria : Comparison of Induction Level and Promoter Strength

    NARCIS (Netherlands)

    Eichenbaum, Zehava; Federle, Michael J.; Marra, Diana; Vos, Willem M. de; Kuipers, Oscar P.; Kleerebezem, Michiel; Scott, June R.

    1998-01-01

    We characterized the regulated activity of the lactococcal nisA promoter in strains of the gram-positive species Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Enterococcus faecalis, and Bacillus subtilis. nisA promoter activity was dependent on the proteins NisR and

  2. The optimization and validation of the Biotyper MALDI-TOF MS database for the identification of Gram-positive anaerobic cocci

    DEFF Research Database (Denmark)

    Veloo, A C M; de Vries, E D; Jean-Pierre, H

    2016-01-01

    Gram-positive anaerobic cocci (GPAC) account for 24%-31% of the anaerobic bacteria isolated from human clinical specimens. At present, GPAC are under-represented in the Biotyper MALDI-TOF MS database. Profiles of new species have yet to be added. We present the optimization of the matrix-assisted......Gram-positive anaerobic cocci (GPAC) account for 24%-31% of the anaerobic bacteria isolated from human clinical specimens. At present, GPAC are under-represented in the Biotyper MALDI-TOF MS database. Profiles of new species have yet to be added. We present the optimization of the matrix......-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) database for the identification of GPAC. Main spectral profiles (MSPs) were created for 108 clinical GPAC isolates. Identity was confirmed using 16S rRNA gene sequencing. Species identification was considered to be reliable...... if the sequence similarity with its closest relative was ≥98.7%. The optimized database was validated using 140 clinical isolates. The 16S rRNA sequencing identity was compared with the MALDI-TOF MS result. MSPs were added from 17 species that were not yet represented in the MALDI-TOF MS database or were under...

  3. Purification and characterization of an extracellular halophilic and organic solvent-tolerant amylopullulanase from a haloarchaeon, Halorubrum sp. strain Ha25.

    Directory of Open Access Journals (Sweden)

    Mostafa Fazeli

    2013-01-01

    Full Text Available Introduction: Halophiles, especially haloarchaea are one of the most important groups of extremophiles. Halophilic hydrolases have been studied worldwide and have been considered for biotechnology and industrial technologies. This study is the first report in amylopullulanase production in halophilic microorganisms.Materials and methods: A halophilic archaeon, Halorubrum sp. strain Ha25, produced extracellular halophilic organic solvent-tolerant amylopullulanase. The enzyme was purified using ethanol precipitation and anion exchange chromatography method. Molecular mass of purified enzyme was determined by SDS–PAGE method. After purification, the enzyme was characterized. To study the effects of organic solvents in the stability of the enzyme, the enzyme solution was incubated in the presence of various organic compounds and then, residual enzyme activity was measured. Mode of action of the enzyme was determined by thin-layer chromatography.Results: Molecular weight of the purified enzyme was estimated to be 140 kDa by SDS–PAGE method. Optimum temperature for amylolitic and pullulytic activities was 50 °C. Optimum pH for amylolitic activity was 7.0 and for pullulytic activity was 7.5. This enzyme was active over a wide range of concentrations (0-4.5 M of NaCl. The effect of organic solvents on the amylolitic and pullulytic activities showed that this enzyme was more stable in the presence of non-polar organic solvents than polar solvents. The enzyme solely hydrolyzed pullulan and soluble starch to glucose.Discussion and conclusion: Halorubrum sp. strain Ha25 produces thermophilic and extremely halophilic amylopullulanase. The catalytic function under multi extreme condition of high temperature, high salinity, and low water activity might possess biotechnological and commercial values such as treatment waste solutions with starch residues, high salt content and solvents.

  4. Bactericidal effect of lactoferrin and lactoferrin chimera against halophilic Vibrio parahaemolyticus

    NARCIS (Netherlands)

    Leon-Sicairos, N.; Canizalez-Roman, A.; de la Garza, M.; Reyes-Lopez, M.; Zazueta-Beltran, J.; Nazmi, K.; Gomez-Gil, B.; Bolscher, J.G.

    2009-01-01

    Infections caused by Vibrio parahaemolyticus, an halophilic member of the genus Vibrio, have increased globally in the last 5 years. Diarrhea caused by V. parahaemolyticus results from eating raw or undercooked seafood. The aim of this work was to investigate whether lactoferrin and some

  5. Bacterial glycobiology: rhamnose-containing cell wall polysaccharides in Gram-positive bacteria.

    Science.gov (United States)

    Mistou, Michel-Yves; Sutcliffe, Iain C; van Sorge, Nina M

    2016-07-01

    The composition of the Gram-positive cell wall is typically described as containing peptidoglycan, proteins and essential secondary cell wall structures called teichoic acids, which comprise approximately half of the cell wall mass. The cell walls of many species within the genera Streptococcus, Enterococcus and Lactococcus contain large amounts of the sugar rhamnose, which is incorporated in cell wall-anchored polysaccharides (CWP) that possibly function as homologues of well-studied wall teichoic acids (WTA). The presence and chemical structure of many rhamnose-containing cell wall polysaccharides (RhaCWP) has sometimes been known for decades. In contrast to WTA, insight into the biosynthesis and functional role of RhaCWP has been lacking. Recent studies in human streptococcal and enterococcal pathogens have highlighted critical roles for these complex polysaccharides in bacterial cell wall architecture and pathogenesis. In this review, we provide an overview of the RhaCWP with regards to their biosynthesis, genetics and biological function in species most relevant to human health. We also briefly discuss how increased knowledge in this field can provide interesting leads for new therapeutic compounds and improve biotechnological applications. © FEMS 2016.

  6. Exploration, antifungal and antiaflatoxigenic activity of halophilic bacteria communities from saline soils of Howze-Soltan playa in Iran.

    Science.gov (United States)

    Jafari, Samaneh; Aghaei, Seyed-Soheil; Afifi-Sabet, Hossein; Shams-Ghahfarokhi, Masoomeh; Jahanshiri, Zahra; Gholami-Shabani, Mohammadhassan; Shafiei-Darabi, Seyedahmad; Razzaghi-Abyaneh, Mehdi

    2018-01-01

    In the present study, halophilic bacteria communities were explored in saline soils of Howze-Soltan playa in Iran with special attention to their biological activity against an aflatoxigenic Aspergillus parasiticus NRRL 2999. Halophilic bacteria were isolated from a total of 20 saline soils using specific culture media and identified by 16S rRNA sequencing in neighbor-joining tree analysis. Antifungal and antiaflatoxigenic activities of the bacteria were screened by a nor-mutant A. parasiticus NRRL 2999 using visual agar plate assay and confirmed by high-performance liquid chromatography. Among a total of 177 halophilic bacteria belonging to 11 genera, 121 isolates (68.3%) inhibited A. parasiticus growth and/or aflatoxin production. The most potent inhibitory bacteria of the genera Bacillus, Paenibacillus and Staphylococcus were distributed in three main phylogenetic clusters as evidenced by 16S rRNA sequence analysis. A. parasiticus growth was inhibited by 0.7-92.7%, while AFB 1 and AFG 1 productions were suppressed by 15.1-98.9 and 57.0-99.6%, respectively. Taken together, halophilic bacteria identified in this study may be considered as potential sources of novel bioactive metabolites as well as promising candidates to develop new biocontrol agents for managing toxigenic fungi growth and subsequent aflatoxin contamination of food and feed in practice.

  7. Characterization of novel Bacillus strain N31 from mariculture water capable of halophilic heterotrophic nitrification-aerobic denitrification.

    Science.gov (United States)

    Huang, Fei; Pan, Luqing; Lv, Na; Tang, Xianming

    2017-11-01

    The development of an intensive aquaculture industry has been accompanied by increasing environmental impacts, especially nitrogen pollution. In this study, a novel halophilic bacterium capable of heterotrophic nitrification and aerobic denitrification was isolated from mariculture water and identified as Bacillus litoralis N31. The efficiency of ammonium, nitrite and nitrate removal by N31 were 86.3%, 89.3% and 89.4%, respectively, after a 48-h cultivation in sole N-source medium with initial nitrogen approximately 20 mg/L. However, ammonium was removed preferentially, and no obvious nitrite accumulated during the simultaneous nitrification and denitrification process in mixed N-source media. The existence of hao, napA and nirS genes further proved the heterotrophic nitrification-aerobic denitrification capability of N31. The optimal conditions for ammonium removal were 30°C, initial pH 7.5-8.5, C/N ratio 5-20 and salinity 30-40‰, and the nitrification rate of N31 increased with increasing initial [Formula: see text] from 10 to 250 mg/L. Biosecurity assessment with shrimp indicated that strain N31 could be applied in the marine aquaculture industry safely for culture water remediation and effluent treatment. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Antimicrobial-Resistance Genetic Markers in Potentially Pathogenic Gram Positive Cocci Isolated from Brazilian Soft Cheese.

    Science.gov (United States)

    Resende, Juliana Alves; Fontes, Cláudia Oliveira; Ferreira-Machado, Alessandra Barbosa; Nascimento, Thiago César; Silva, Vânia Lúcia; Diniz, Cláudio Galuppo

    2018-02-01

    Although most Brazilian dairy products meet high technological standards, there are quality issues regarding milk production, which may reduce the final product quality. Several microbial species may contaminate milk during manufacture and handling. If antimicrobial usage remains uncontrolled in dairy cattle, the horizontal transfer of antimicrobial resistance genes in foodstuffs may be of particular concern for both food producers and dairy industry. This study focused on the evaluation of putative Gram positive cocci in Minas cheese and of antimicrobial and biocide resistance genes among the isolated bacteria. Representative samples of 7 different industrially trademarked Minas cheeses (n = 35) were processed for selective culture and isolation of Gram positive cocci. All isolated bacteria were identified by DNA sequencing of the 16S rRNA gene. Antimicrobial resistance genes were screened by PCR. Overall, 208 strains were isolated and identified as follows: Enterococcus faecalis (47.6%), Macrococcus caseolyticus (18.3%), Enterococcus faecium (11.5%), Enterococcus caseliflavus (7.7%), Staphylococcus haemolyticus (7.2%), Staphylococcus aureus (4.3%), Staphylococcus epidermidis (2.9%), and Enterococcus hirae (0.5%). The genetic markers mecA (78.0%) and smr (71.4%) were the most prevalent, but others were also detected, such as blaZ (65.2%), msrA (60.9%), msrB (46.6%), linA (54.7%), and aacA-aphD (47.6%). The occurrence of opportunist pathogenic bacteria harboring antimicrobial resistance markers in the cheese samples are of special concern, since these bacteria are not considered harmful contaminating agents according to the Brazilian sanitary regulations. However, they are potentially pathogenic bacteria and the cheese may be considered a reservoir for antimicrobial resistance genes available for horizontal transfer through the food chain, manufacturing personnel and consumers. © 2018 Institute of Food Technologists®.

  9. An unusual class of anthracyclines potentiate Gram-positive antibiotics in intrinsically resistant Gram-negative bacteria.

    Science.gov (United States)

    Cox, Georgina; Koteva, Kalinka; Wright, Gerard D

    2014-07-01

    An orthogonal approach taken towards novel antibacterial drug discovery involves the identification of small molecules that potentiate or enhance the activity of existing antibacterial agents. This study aimed to identify natural-product rifampicin adjuvants in the intrinsically resistant organism Escherichia coli. E. coli BW25113 was screened against 1120 actinomycete fermentation extracts in the presence of subinhibitory (2 mg/L) concentrations of rifampicin. The active molecule exhibiting the greatest rifampicin potentiation was isolated using activity-guided methods and identified using mass and NMR spectroscopy. Susceptibility testing and biochemical assays were used to determine the mechanism of antibiotic potentiation. The anthracycline Antibiotic 301A(1) was isolated from the fermentation broth of a strain of Streptomyces (WAC450); the molecule was shown to be highly synergistic with rifampicin (fractional inhibitory concentration index = 0.156) and moderately synergistic with linezolid (FIC index = 0.25) in both E. coli and Acinetobacter baumannii. Activity was associated with inhibition of efflux and the synergistic phenotype was lost when tested against E. coli harbouring mutations within the rpoB gene. Structure-activity relationship studies revealed that other anthracyclines do not synergize with rifampicin and removal of the sugar moiety of Antibiotic 301A(1) abolishes activity. Screening only a subsection of our natural product library identified a small-molecule antibiotic adjuvant capable of sensitizing Gram-negative bacteria to antibiotics to which they are ordinarily intrinsically resistant. This result demonstrates the great potential of this approach in expanding antibiotic effectiveness in the face of the growing challenge of resistance in Gram-negatives. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. Genomic adaptations of the halophilic Dead Sea filamentous fungus Eurotium rubrum.

    Science.gov (United States)

    Kis-Papo, Tamar; Weig, Alfons R; Riley, Robert; Peršoh, Derek; Salamov, Asaf; Sun, Hui; Lipzen, Anna; Wasser, Solomon P; Rambold, Gerhard; Grigoriev, Igor V; Nevo, Eviatar

    2014-05-09

    The Dead Sea is one of the most hypersaline habitats on Earth. The fungus Eurotium rubrum (Eurotiomycetes) is among the few species able to survive there. Here we highlight its adaptive strategies, based on genome analysis and transcriptome profiling. The 26.2 Mb genome of E. rubrum shows, for example, gains in gene families related to stress response and losses with regard to transport processes. Transcriptome analyses under different salt growth conditions revealed, among other things differentially expressed genes encoding ion and metabolite transporters. Our findings suggest that long-term adaptation to salinity requires cellular and metabolic responses that differ from short-term osmotic stress signalling. The transcriptional response indicates that halophilic E. rubrum actively counteracts the salinity stress. Many of its genes encode for proteins with a significantly higher proportion of acidic amino acid residues. This trait is characteristic of the halophilic prokaryotes as well, supporting the theory of convergent evolution under extreme hypersaline stress.

  11. Lack of clinical utility of urine gram stain for suspected urinary tract infection in pediatric patients.

    Science.gov (United States)

    Cantey, Joseph B; Gaviria-Agudelo, Claudia; McElvania TeKippe, Erin; Doern, Christopher D

    2015-04-01

    Urinary tract infection (UTI) is one of the most common infections in children. Urine culture remains the gold standard for diagnosis, but the utility of urine Gram stain relative to urinalysis (UA) is unclear. We reviewed 312 pediatric patients with suspected UTI who had urine culture, UA, and urine Gram stain performed from a single urine specimen. UA was considered positive if ≥10 leukocytes per oil immersion field were seen or if either nitrates or leukocyte esterase testing was positive. Urine Gram stain was considered positive if any organisms were seen. Sensitivity, specificity, and positive and negative predictive values were calculated using urine culture as the gold standard. Thirty-seven (12%) patients had a culture-proven UTI. Compared to urine Gram stain, UA had equal sensitivity (97.3% versus 97.5%) and higher specificity (85% versus 74%). Empirical therapy was prescribed before the Gram stain result was known in 40 (49%) patients and after in 42 (51%) patients. The antibiotics chosen did not differ between the two groups (P=0.81), nor did they differ for patients with Gram-negative rods on urine Gram stain compared to those with Gram-positive cocci (P=0.67). From these data, we conclude that UA has excellent negative predictive value that is not enhanced by urine Gram stain and that antibiotic selection did not vary based on the urine Gram stain result. In conclusion, the clinical utility of urine Gram stain does not warrant the time or cost it requires. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. The use of Gram stain and matrix-assisted laser desorption ionization time-of-flight mass spectrometry on positive blood culture: synergy between new and old technology.

    Science.gov (United States)

    Fuglsang-Damgaard, David; Nielsen, Camilla Houlberg; Mandrup, Elisabeth; Fuursted, Kurt

    2011-10-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is promising as an alternative to more costly and cumbersome methods for direct identifications in blood cultures. We wanted to evaluate a simplified pre-treatment method for using MALDI-TOF-MS directly on positive blood cultures using BacT/Alert blood culture system, and to test an algorithm combining the result of the initial microscopy with the result suggested by MALDI-TOF-MS. Using the recommended cut-off score of 1.7 the best results were obtained among Gram-negative rods with correct identifications in 91% of Enterobacteriaceae, 83% in aerobic/non-fermentative Gram-negative rods, whereas results were more modest among Gram-positive cocci with correct identifications in 52% of Staphylococci, 54% in Enterococci and only 20% in Streptococci. Combining the results of Gram stain with the top reports by MALDI-TOF-MS, increased the sensitivity from 91% to 93% in the score range from 1.5 to 1.7 and from 48% to 85% in the score range from 1.3 to 1.5. Thus, using this strategy and accepting a cut-off at 1.3 instead of the suggested 1.7, overall sensitivity could be increased from 88.1% to 96.3%. MALDI-TOF-MS is an efficient method for direct routine identification of bacterial isolates in blood culture, especially when combined with the result of the Gram stain. © 2011 The Authors. APMIS © 2011 APMIS.

  13. Halophilic mechanism of the enzymatic function of a moderately halophilic dihydrofolate reductase from Haloarcula japonica strain TR-1.

    Science.gov (United States)

    Miyashita, Yurina; Ohmae, Eiji; Ikura, Teikichi; Nakasone, Kaoru; Katayanagi, Katsuo

    2017-05-01

    Dihydrofolate (DHF) reductase coded by a plasmid of the extremely halophilic archaeon Haloarcula japonica strain TR-1 (HjDHFR P1) shows moderate halophilicity on enzymatic activity at pH 6.0, although there is no significant effect of NaCl on its secondary structure. To elucidate the salt-activation and -inactivation mechanisms of this enzyme, we investigated the effects of pH and salt concentration, deuterium isotope effect, steady-state kinetics, and rapid-phase ligand-binding kinetics. Enzyme activity was increased eightfold by the addition of 500 mM NaCl at pH 6.0, fourfold by 250 mM at pH 8.0, and became independent of salt concentration at pH 10.0. Full isotope effects observed at pH 10.0 under 0-1000 mM NaCl indicated that the rate of hydride transfer, which was the rate-determining step at the basic pH region, was independent of salt concentration. Conversely, rapid-phase ligand-binding experiments showed that the amplitude of the DHF-binding reaction increased and the tetrahydrofolate (THF)-releasing rate decreased with increasing NaCl concentration. These results suggested that the salt-activation mechanism of HjDHFR P1 is via the population change of the anion-unbound and anion-bound conformers, which are binding-incompetent and -competent conformations for DHF, respectively, while that of salt inactivation is via deceleration of the THF-releasing rate, which is the rate-determining step at the neutral pH region.

  14. Gelria glutamica gen. nov., sp. a thermophilic oligately syntrophic glutamate-degrading anaerobe

    NARCIS (Netherlands)

    Plugge, C.M.; Balk, M.; Zoetendal, E.G.; Stams, A.J.M.

    2002-01-01

    A novel anaerobic, Gram-positive, thermophilic, spore-forming, obligately syntrophic, glutamate-degrading bacterium, strain TGO(T), was isolated from a propionate-oxidizing methanogenic enrichment culture. The axenic culture was obtained by growing the bacterium on pyruvate. Cells were rod-shaped

  15. Spiribacter curvatus sp. nov., a moderately halophilic bacterium isolated from a saltern.

    Science.gov (United States)

    León, María José; Rodríguez-Olmos, Angel; Sánchez-Porro, Cristina; López-Pérez, Mario; Rodríguez-Valera, Francisco; Soliveri, Juan; Ventosa, Antonio; Copa-Patiño, José Luis

    2015-12-01

    A novel pink-pigmented bacterial strain, UAH-SP71T, was isolated from a saltern located in Santa Pola, Alicante (Spain) and the complete genome sequence was analysed and compared with that of Spiribacter salinus M19-40T, suggesting that the two strains constituted two separate species, with a 77.3% ANI value. In this paper, strain UAH-SP71T was investigated in a taxonomic study using a polyphasic approach. Strain UAH-SP71T was a Gram-stain-negative, strictly aerobic, non-motile curved rod that grew in media containing 5-20% (w/v) NaCl (optimum 10% NaCl), at 5-40 °C (optimum 37 °C) and at pH 5-10 (optimum pH 8). Phylogenetic analysis based on the comparison of 16S rRNA gene sequences revealed thatstrain UAH-SP71T is a member of the genus Spiribacter, showing a sequence similarity of 96.5% with Spiribacter salinus M19-40T. Other related species are also members of the family Ectothiorhodospiraceae, including Arhodomonas recens RS91T (95.5% 16S rRNA gene sequence similarity), Arhodomonas aquaeolei ATCC 49307T (95.4 %) and Alkalilimnicola ehrlichii MLHE-1T (94.9 %). DNA-DNA hybridization between strain UAH-SP71T and Spiribacter salinus M19-40T was 39 %. The major cellular fatty acids of strain UAH-SP71T were C18 : 1ω6c and/or C18 : 1ω7c, C16 : 0, C16 : 1ω6c and/or C16 : 1ω7c, C10 : 0 3-OH and C12 : 0, a pattern similar to that of Spiribacter salinus M19-40T. Phylogenetic, phenotypic and genotypic differences between strain UAH-SP71T and Spiribacter salinus M19-40T indicate that strainUAH-SP71T represents a novel species of the genus Spiribacter, for which the name Spiribacter curvatus sp. nov. is proposed. The type strain is UAH-SP71T (5CECT8396T5DSM 28542T).

  16. Halophilic and halotolerant actinomycetes from a marine saltern of Goa, India producing anti-bacterial metabolites.

    Science.gov (United States)

    Ballav, Shuvankar; Kerkar, Savita; Thomas, Sabu; Augustine, Nimmy

    2015-03-01

    Marine salterns are estuarine ecosystems in Goa, receiving inputs from riverine and marine waters. The Salinity fluctuates between 0 and 300 psu which makes it a conducive niche for salt tolerant and salt loving Actinomycetales. Halotolerant and halophilic Actinomycetales producing anti-bacterial metabolites were studied from crystallizer pond sediments of Ribandar saltern, Goa. Three media viz. Starch casein, R2A and Inorganic salt starch agar at four different salinities (35, 50, 75 and 100 psu) were used for isolation. R2A agar at 35 psu was the most preferred by hypersaline actinomycetes. The dominant group was halotolerant Streptomyces spp. others being rare actinomycetes viz. Nocardiopsis, Micromonospora and Kocuria spp. More than 50% of the isolates showed anti-bacterial activity against one or more of the fifteen human pathogens tested. Eight strains from 4 genera showed consistent anti-bacterial activity and studied in detail. Most halotolerant isolates grew from 0 to 75 psu, with optimum antibiotic production at 35 psu whereas halophiles grew at 20 to 100 psu with optimum antibiotic production at 35 psu. Four Streptomyces strains showed multiple inhibition against test organisms while four rare actinomycetes were specific in their inhibitory activity. This is the first report of a halophilic Kocuria sp., Nocardiopsis sp., and halotolerant Micromonospora sp. producing anti-bacterial compound(s) against Staphylococcus aureus, Staphylococcus citreus, and Vibrio cholerae, respectively. Sequential extraction with varying polarity of organic solvents showed that the extracts inhibited different test pathogens. These results suggest that halophilic and halotolerant actinomycetes from marine salterns are a potential source of anti-bacterial compounds. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. Diversity and enumeration of halophilic and alkaliphilic bacteria in Spanish-style green table-olive fermentations.

    Science.gov (United States)

    Lucena-Padrós, Helena; Ruiz-Barba, José Luis

    2016-02-01

    The presence and enumeration of halophilic and alkaliphilic bacteria in Spanish-style table-olive fermentations was studied. Twenty 10-tonne fermenters at two large manufacturing companies in Spain, previously studied through both culture dependent and independent (PCR-DGGE) methodologies, were selected. Virtually all this microbiota was isolated during the initial fermentation stage. A total of 203 isolates were obtained and identified based on 16S rRNA gene sequences. They belonged to 13 bacterial species, included in 11 genera. It was noticeable the abundance of halophilic and alkaliphilic lactic acid bacteria (HALAB). These HALAB belonged to the three genera of this group: Alkalibacterium, Marinilactibacillus and Halolactibacillus. Ten bacterial species were isolated for the first time from table olive fermentations, including the genera Amphibacillus, Natronobacillus, Catenococcus and Streptohalobacillus. The isolates were genotyped through RAPD and clustered in a dendrogram where 65 distinct strains were identified. Biodiversity indexes found statistically significant differences between both patios regarding genotype richness, diversity and dominance. However, Jaccard similarity index suggested that the halophilic/alkaliphilic microbiota in both patios was more similar than the overall microbiota at the initial fermentation stage. Thus, up to 7 genotypes of 6 different species were shared, suggesting adaptation of some strains to this fermentation stage. Morisita-Horn similarity index indicated a high level of codominance of the same species in both patios. Halophilic and alkaliphilic bacteria, especially HALAB, appeared to be part of the characteristic microbiota at the initial stage of this table-olive fermentation, and they could contribute to the conditioning of the fermenting brines in readiness for growth of common lactic acid bacteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Solid-state fermentation as a potential technique for esterase/lipase production by halophilic archaea.

    Science.gov (United States)

    Martin del Campo, Martha; Camacho, Rosa M; Mateos-Díaz, Juan C; Müller-Santos, Marcelo; Córdova, Jesus; Rodríguez, Jorge A

    2015-11-01

    Halophilic archaea are extremophiles, adapted to high-salt environments, showing a big biotechnological potential as enzyme, lipids and pigments producers. Four inert supports (perlite, vermiculite, polyurethane foam and glass fiber) were employed for solid-state fermentation (SSF) of the halophilic archaeon Natronococcus sp. TC6 to investigate biomass and esterase production. A very low esterase activity and high water activity were observed when perlite, vermiculite and polyurethane were used as supports. When glass fiber was employed, an important moisture loss was observed (8.6%). Moreover, moisture retention was improved by mixing polyurethane and glass fiber, resulting in maximal biomass and esterase production. Three halophilic archaea: Natronococcus sp. TC6, Halobacterium sp. NRC-1 and Haloarcula marismortui were cultured by submerged fermentation (SmF) and by SSF; an improvement of 1.3- to 6.2-fold was observed in the biomass and esterase production when SSF was used. Growth was not homogeneous in the mixture, but was predominant in the glass fiber thus was probably because the glass fiber provides a holder to the cells, while the polyurethane acts as an impregnation medium reservoir. To the best of our knowledge, this work is the first report on haloarchaea cultivation by SSF aiming biomass and esterase/lipase activity production.

  19. Effect of UVC Radiation on Hydrated and Desiccated Cultures of Slightly Halophilic and Non-Halophilic Methanogenic Archaea: Implications for Life on Mars.

    Science.gov (United States)

    Sinha, Navita; Kral, Timothy A

    2018-05-12

    Methanogens have been considered models for life on Mars for many years. In order to survive any exposure at the surface of Mars, methanogens would have to endure Martian UVC radiation. In this research, we irradiated hydrated and desiccated cultures of slightly halophilic Methanococcus maripaludis and non-halophilic Methanobacterium formicicum for various time intervals with UVC (254 nm) radiation. The survivability of the methanogens was determined by measuring methane concentrations in the headspace gas samples of culture tubes after re-inoculation of the methanogens into their growth-supporting media following exposure to UVC radiation. Hydrated M. maripaludis survived 24 h of UVC exposure, while in a desiccated condition they endured for 16 h. M. formicicum also survived UVC radiation for 24 h in a liquid state; however, in a desiccated condition, the survivability of M. formicicum was only 12 h. Some of the components of the growth media could have served as shielding agents that protected cells from damage caused by exposure to ultraviolet radiation. Overall, these results suggest that limited exposure (12⁻24 h) to UVC radiation on the surface of Mars would not necessarily be a limiting factor for the survivability of M. maripaludis and M. formicicum .

  20. Carboxydobrachium pacificum gen. nov., sp. nov., a new anaerobic, thermophilic, CO-utilizing marine bacterium from Okinawa Trough.

    Science.gov (United States)

    Sokolova, T G; González, J M; Kostrikina, N A; Chernyh, N A; Tourova, T P; Kato, C; Bonch-Osmolovskaya, E A; Robb, F T

    2001-01-01

    A new anaerobic, thermophilic, CO-utilizing marine bacterium, strain JMT, was isolated from a submarine hot vent in Okinawa Trough. Cells of strain JMT were non-motile thin straight rods, sometimes branching, with a cell wall of the Gram-positive type, surrounded with an S-layer. Chains of three to five cells were often observed. The isolate grew chemolithotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO+H2O-->CO2+H2) and organotrophically on peptone, yeast extract, starch, cellobiose, glucose, galactose, fructose and pyruvate, producing H2, acetate and CO2. Growth was observed from 50 to 80 degrees C with an optimum at 70 degrees C. The optimum pH was 6.8-7.1. The optimum concentration of sea salts in the medium was 20.5-25.5 g l(-1). The generation time under optimal conditions was 7.1 h. The DNA G+C content was 33 mol %. Growth of isolate JMT was not inhibited by penicillin, but ampicillin, streptomycin, kanamycin and neomycin completely inhibited growth. The results of 16S rDNA sequence analysis revealed that strain JMT belongs to the Thermoanaerobacter phylogenetic group within the Bacillus-Clostridium subphylum of Gram-positive bacteria but represents a separate branch of this group. On the basis of morphological and physiological features and phylogenetic data, this isolate should be assigned to a new genus, for which the name Carboxydobrachium is proposed. The type species is Carboxydobrachium pacificum; the type strain is JMT (= DSM 12653T).

  1. Therapeutic Potential of a Scorpion Venom-Derived Antimicrobial Peptide and Its Homologs Against Antibiotic-Resistant Gram-Positive Bacteria

    Directory of Open Access Journals (Sweden)

    Gaomin Liu

    2018-05-01

    Full Text Available The alarming rise in the prevalence of antibiotic resistance among pathogenic bacteria poses a unique challenge for the development of effective therapeutic agents. Antimicrobial peptides (AMPs have attracted a great deal of attention as a possible solution to the increasing problem of antibiotic-resistant bacteria. Marcin-18 was identified from the scorpion Mesobuthus martensii at both DNA and protein levels. The genomic sequence revealed that the marcin-18 coding gene contains a phase-I intron with a GT-AG splice junction located in the DNA region encoding the N-terminal part of signal peptide. The peptide marcin-18 was also isolated from scorpion venom. A protein sequence homology search revealed that marcin-18 shares extremely high sequence identity to the AMPs meucin-18 and megicin-18. In vitro, chemically synthetic marcin-18 and its homologs (meucin-18 and megicin-18 showed highly potent inhibitory activity against Gram-positive bacteria, including some clinical antibiotic-resistant strains. Importantly, in a mouse acute peritonitis model, these peptides significantly decreased the bacterial load in ascites and rescued nearly all mice heavily infected with clinical methicillin-resistant Staphylococcus aureus from lethal bacteremia. Peptides exerted antimicrobial activity via a bactericidal mechanism and killed bacteria through membrane disruption. Taken together, marcin-18 and its homologs have potential for development as therapeutic agents for treating antibiotic-resistant, Gram-positive bacterial infections.

  2. Gram staining in the diagnosis of acute septic arthritis.

    Science.gov (United States)

    Faraj, A A; Omonbude, O D; Godwin, P

    2002-10-01

    This study aimed at determining the sensitivity and specificity of Gram staining of synovial fluid as a diagnostic tool in acute septic arthritis. A retrospective study was made of 22 patients who had arthroscopic lavage following a provisional diagnosis of acute septic arthritis of the knee joint. Gram stains and cultures of the knee aspirates were compared with the clinical and laboratory parameters, to evaluate their usefulness in diagnosing acute arthritis. All patients who had septic arthritis had pain, swelling and limitation of movement. CRP was elevated in 90% of patients. The incidence of elevated white blood cell count was higher in the group of patients with a positive Gram stain study (60%) as compared to patients with a negative Gram stain study (33%). Gram staining sensitivity was 45%. Its specificity was however 100%. Gram staining is an unreliable tool in early decision making in patients requiring urgent surgical drainage and washout.

  3. Distinct Osmoadaptation Strategies in the Strict Halophilic and Halotolerant Bacteria Isolated from Lunsu Salt Water Body of North West Himalayas.

    Science.gov (United States)

    Vaidya, Shivani; Dev, Kamal; Sourirajan, Anuradha

    2018-07-01

    Two strict halophilic bacterial strains, Halobacillus trueperi SS1, and Halobacillus trueperi SS3, and three halotolerant bacterial strains, Shewanella algae SS2, Halomonas venusta SS5, and Marinomonas sp. SS8 of Lunsu salt water body, Himachal Pradesh, India, were selected to study the mechanism of salt tolerance and the role of osmolytes therein. A combination of flame photometry, chromatographic and colorimetric assays was used to study the mechanism of salt tolerance in the selected strict halophilic and halotolerant bacterial strains. The strict halophiles and, one of the halotolerants, Marinomonas sp. SS8 were found to utilize both "salt-in strategy" and "accumulation of compatible solutes strategy" for osmoregulation in hypersaline conditions. On the contrary, the remaining two halotolerants used "accumulation of compatible solutes strategy" under saline stress and not the "salt-in strategy". The present study suggests towards distinct mechanisms of salt tolerance in the two classes, wherein strict halophiles accumulate compatible solutes as well as adopt salt-in strategy, while the halotolerant bacteria accumulate a range of compatible solutes, except Marinomonas sp. SS8, which utilizes both the strategies to combat salt stress.

  4. Evaluation of biodecolorization of the textile azo dye by halophilic archaea

    Directory of Open Access Journals (Sweden)

    Masoomeh Selseleh Hassan-Kiadehi

    2017-09-01

    Discussion and conclusion: In conclusion, our results indicate that halophilic archaea have very high potential to decolorize azo dyes. Regarding high amounts of salts in textile wastewaters, using such microorganisms which can tolerate the harsh environment in order to decolorize azo dyes, could be a new approach in this field.

  5. Roseimarinus sediminis gen. nov., sp. nov., a facultatively anaerobic bacterium isolated from coastal sediment.

    Science.gov (United States)

    Wu, Wen-Jie; Liu, Qian-Qian; Chen, Guan-Jun; Du, Zong-Jun

    2015-07-01

    A Gram-stain-negative, facultatively anaerobic, non-motile and pink-pigmented bacterium, designated strain HF08(T), was isolated from marine sediment of the coast of Weihai, China. Cells were rod-shaped, and oxidase- and catalase-positive. The isolate grew optimally at 33 °C, at pH 7.5-8.0 and with 2-3% (w/v) NaCl. The dominant cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C14 : 0. Menaquinone 7 (MK-7) was the major respiratory quinone and the DNA G+C content was 44.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was a member of the class Bacteroidia, and shared 88-90% sequence similarity with the closest genera Sunxiuqinia, Prolixibacter, Draconibacterium, Mariniphaga and Meniscus. Based on the phylogenetic and phenotypic evidence presented, a novel species in a new genus of the family Prolixibacteraceae is proposed, with the name Roseimarinus sediminis gen. nov., sp. nov. The type strain of Roseimarinus sediminis is HF08(T) ( = KCTC 42261(T) = CICC 10901(T)).

  6. Automated Interpretation of Blood Culture Gram Stains by Use of a Deep Convolutional Neural Network.

    Science.gov (United States)

    Smith, Kenneth P; Kang, Anthony D; Kirby, James E

    2018-03-01

    Microscopic interpretation of stained smears is one of the most operator-dependent and time-intensive activities in the clinical microbiology laboratory. Here, we investigated application of an automated image acquisition and convolutional neural network (CNN)-based approach for automated Gram stain classification. Using an automated microscopy platform, uncoverslipped slides were scanned with a 40× dry objective, generating images of sufficient resolution for interpretation. We collected 25,488 images from positive blood culture Gram stains prepared during routine clinical workup. These images were used to generate 100,213 crops containing Gram-positive cocci in clusters, Gram-positive cocci in chains/pairs, Gram-negative rods, or background (no cells). These categories were targeted for proof-of-concept development as they are associated with the majority of bloodstream infections. Our CNN model achieved a classification accuracy of 94.9% on a test set of image crops. Receiver operating characteristic (ROC) curve analysis indicated a robust ability to differentiate between categories with an area under the curve of >0.98 for each. After training and validation, we applied the classification algorithm to new images collected from 189 whole slides without human intervention. Sensitivity and specificity were 98.4% and 75.0% for Gram-positive cocci in chains and pairs, 93.2% and 97.2% for Gram-positive cocci in clusters, and 96.3% and 98.1% for Gram-negative rods. Taken together, our data support a proof of concept for a fully automated classification methodology for blood-culture Gram stains. Importantly, the algorithm was highly adept at identifying image crops with organisms and could be used to present prescreened, classified crops to technologists to accelerate smear review. This concept could potentially be extended to all Gram stain interpretive activities in the clinical laboratory. Copyright © 2018 American Society for Microbiology.

  7. Insights into Head-Tailed Viruses Infecting Extremely Halophilic Archaea

    Science.gov (United States)

    Pietilä, Maija K.; Laurinmäki, Pasi; Russell, Daniel A.; Ko, Ching-Chung; Jacobs-Sera, Deborah; Butcher, Sarah J.

    2013-01-01

    Extremophilic archaea, both hyperthermophiles and halophiles, dominate in habitats where rather harsh conditions are encountered. Like all other organisms, archaeal cells are susceptible to viral infections, and to date, about 100 archaeal viruses have been described. Among them, there are extraordinary virion morphologies as well as the common head-tailed viruses. Although approximately half of the isolated archaeal viruses belong to the latter group, no three-dimensional virion structures of these head-tailed viruses are available. Thus, rigorous comparisons with bacteriophages are not yet warranted. In the present study, we determined the genome sequences of two of such viruses of halophiles and solved their capsid structures by cryo-electron microscopy and three-dimensional image reconstruction. We show that these viruses are inactivated, yet remain intact, at low salinity and that their infectivity is regained when high salinity is restored. This enabled us to determine their three-dimensional capsid structures at low salinity to a ∼10-Å resolution. The genetic and structural data showed that both viruses belong to the same T-number class, but one of them has enlarged its capsid to accommodate a larger genome than typically associated with a T=7 capsid by inserting an additional protein into the capsid lattice. PMID:23283946

  8. On the Response of Halophilic Archaea to Space Conditions

    Science.gov (United States)

    Leuko, Stefan; Rettberg, Petra; Pontifex, Ashleigh L.; Burns, Brendan P.

    2014-01-01

    Microorganisms are ubiquitous and can be found in almost every habitat and ecological niche on Earth. They thrive and survive in a broad spectrum of environments and adapt to rapidly changing external conditions. It is of great interest to investigate how microbes adapt to different extreme environments and with modern human space travel, we added a new extreme environment: outer space. Within the last 50 years, technology has provided tools for transporting microbial life beyond Earth’s protective shield in order to study in situ responses to selected conditions of space. This review will focus on halophilic archaea, as, due to their ability to survive in extremes, they are often considered a model group of organisms to study responses to the harsh conditions associated with space. We discuss ground-based simulations, as well as space experiments, utilizing archaea, examining responses and/or resistance to the effects of microgravity and UV in particular. Several halophilic archaea (e.g., Halorubrum chaoviator) have been exposed to simulated and actual space conditions and their survival has been determined as well as the protective effects of halite shown. Finally, the intriguing potential of archaea to survive on other planets or embedded in a meteorite is postulated. PMID:25370029

  9. Metabolic flux analysis of the halophilic archaeon Haladaptatus paucihalophilus.

    Science.gov (United States)

    Liu, Guangxiu; Zhang, Manxiao; Mo, Tianlu; He, Lian; Zhang, Wei; Yu, Yi; Zhang, Qi; Ding, Wei

    2015-11-27

    This work reports the (13)C-assisted metabolic flux analysis of Haladaptatus paucihalophilus, a halophilic archaeon possessing an intriguing osmoadaption mechanism. We showed that the carbon flow is through the oxidative tricarboxylic acid (TCA) cycle whereas the reductive TCA cycle is not operative in H. paucihalophilus. In addition, both threonine and the citramalate pathways contribute to isoleucine biosynthesis, whereas lysine is synthesized through the diaminopimelate pathway and not through the α-aminoadipate pathway. Unexpected, the labeling patterns of glycine from the cells grown on [1-(13)C]pyruvate and [2-(13)C]pyruvate suggest that, unlike all the organisms investigated so far, in which glycine is produced exclusively from the serine hydroxymethyltransferase (SHMT) pathway, glycine biosynthesis in H. paucihalophilus involves different pathways including SHMT, threonine aldolase (TA) and the reverse reaction of glycine cleavage system (GCS), demonstrating for the first time that other pathways instead of SHMT can also make a significant contribution to the cellular glycine pool. Transcriptional analysis confirmed that both TA and GCS genes were transcribed in H. paucihalophilus, and the transcriptional level is independent of salt concentrations in the culture media. This study expands our understanding of amino acid biosynthesis and provides valuable insights into the metabolism of halophilic archaea. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. On the Response of Halophilic Archaea to Space Conditions

    Directory of Open Access Journals (Sweden)

    Stefan Leuko

    2014-02-01

    Full Text Available Microorganisms are ubiquitous and can be found in almost every habitat and ecological niche on Earth. They thrive and survive in a broad spectrum of environments and adapt to rapidly changing external conditions. It is of great interest to investigate how microbes adapt to different extreme environments and with modern human space travel, we added a new extreme environment: outer space. Within the last 50 years, technology has provided tools for transporting microbial life beyond Earth’s protective shield in order to study in situ responses to selected conditions of space. This review will focus on halophilic archaea, as, due to their ability to survive in extremes, they are often considered a model group of organisms to study responses to the harsh conditions associated with space. We discuss ground-based simulations, as well as space experiments, utilizing archaea, examining responses and/or resistance to the effects of microgravity and UV in particular. Several halophilic archaea (e.g., Halorubrum chaoviator have been exposed to simulated and actual space conditions and their survival has been determined as well as the protective effects of halite shown. Finally, the intriguing potential of archaea to survive on other planets or embedded in a meteorite is postulated.

  11. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    Directory of Open Access Journals (Sweden)

    Servé W. M. Kengen

    2013-01-01

    Full Text Available Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the research on C. saccharolyticus with respect to the hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, and the regulation of the redox and carbon metabolism. Analysis of currently available fermentation data reveal decreased hydrogen yields under non-ideal cultivation conditions, which are mainly associated with the accumulation of hydrogen in the liquid phase. Thermodynamic considerations concerning the reactions involved in hydrogen formation are discussed with respect to the dissolved hydrogen concentration. Novel cultivation data demonstrate the sensitivity of C. saccharolyticus to increased hydrogen levels regarding substrate load and nitrogen limitation. In addition, special attention is given to the rhamnose metabolism, which represents an unusual type of redox balancing. Finally, several approaches are suggested to improve biohydrogen production by C. saccharolyticus.

  12. Isolation and identification of poly-extremophilic alkalophilic, halophilic and halotolerant bacteria from alkaline thalassohaline Gomishan wetland

    Directory of Open Access Journals (Sweden)

    Azadeh Shahinpei

    2013-06-01

    Full Text Available Gomishan wetland is a natural ecosystem located in 35 km north west of Gorgan, in the west vicinity of Khajeh Nafas city and Gomishan. Twice sampling from 3 different geographic positions in dry and rainy seasons, led to the isolation of 224 isolates. For 57 isolates, halophilic and halotolerant behaviors and also optimum and growth range in different pH and temperatures were determined. Most of the moderately halophilic and halotolerant strains were capable of growing optimally in media with pH 8.5-9 and optimum growth temperatures ranging from <4 to 40 °C. The isolates were examined for hydrolytic enzymes production. Most of the isolates showed lipase activites and a total of 15, 7 and 3 strains produced amylases, proteases and DNases, respectively. The enzymes could be useful in some industrial processes. 16S rDNA phylogenetic analysis were done for 55 strains. According to this analysis, strains were placed in 22 different genera: Achromobacter, Aeromicrobium, Altererythrobacter, Bacillus, Caenispirillum, Cyclobacterium, Erythrobacter, Halobacillus, Halomonas, Idiomarina, Jonesia, Marinobacter, Martelella, Nesiotobacter, Paenibacillus, Planococcus, Pseudomonas, Rheinheimera, Saccharospirillum, Stappia, Thalassospira and Vibrio. 23% of these strains were haloalkalophilic bacteria and belonged to the Bacillus, Halobacillus, Halomonas, Idiomarina and Marinobacter. This was the first study on the culturable bacteria at Gomishan wetland, an area of considerable alkaline thalassohaline ecosystem.

  13. Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria

    Directory of Open Access Journals (Sweden)

    Muscariello Lidia

    2006-05-01

    Full Text Available Abstract Background Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. Results A novel gene cluster encoding exclusively cell-surface proteins was identified, which is conserved in a subgroup of gram-positive bacteria. Each gene cluster generally has one copy of four new gene families called cscA, cscB, cscC and cscD. Clusters encoding these cell-surface proteins were found only in complete genomes of Lactobacillus plantarum, Lactobacillus sakei, Enterococcus faecalis, Listeria innocua, Listeria monocytogenes, Lactococcus lactis ssp lactis and Bacillus cereus and in incomplete genomes of L. lactis ssp cremoris, Lactobacillus casei, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillius brevis, Oenococcus oeni, Leuconostoc mesenteroides, and Bacillus thuringiensis. These genes are neither present in the genomes of streptococci, staphylococci and clostridia, nor in the Lactobacillus acidophilus group, suggesting a niche-specific distribution, possibly relating to association with plants. All encoded proteins have a signal peptide for secretion by the Sec-dependent pathway, while some have cell-surface anchors, novel WxL domains, and putative domains for sugar binding and degradation. Transcriptome analysis in L. plantarum shows that the cscA-D genes are co-expressed, supporting their operon organization. Many gene clusters are significantly up-regulated in a glucose-grown, ccpA-mutant derivative of L. plantarum, suggesting catabolite control. This is supported by the presence of predicted CRE-sites upstream or inside the up-regulated cscA-D gene clusters. Conclusion We propose that the CscA, CscB, CscC and Csc

  14. Halomonas titanicae sp. nov., a halophilic bacterium isolated from the RMS Titanic.

    Science.gov (United States)

    Sánchez-Porro, Cristina; Kaur, Bhavleen; Mann, Henrietta; Ventosa, Antonio

    2010-12-01

    A Gram-negative, heterotrophic, aerobic, non-endospore-forming, peritrichously flagellated and motile bacterial strain, designated BH1(T), was isolated from samples of rusticles, which are formed in part by a consortium of micro-organisms, collected from the RMS Titanic wreck site. The strain grew optimally at 30-37°C, pH 7.0-7.5 and in the presence of 2-8 % (w/v) NaCl. We carried out a polyphasic taxonomic study in order to characterize the strain in detail. Phylogenetic analyses based on 16S rRNA gene sequence comparison indicated that strain BH1(T) clustered within the branch consisting of species of Halomonas. The most closely related type strains were Halomonas neptunia (98.6 % 16S rRNA sequence similarity), Halomonas variabilis (98.4 %), Halomonas boliviensis (98.3 %) and Halomonas sulfidaeris (97.5 %). Other closely related species were Halomonas alkaliphila (96.5 % sequence similarity), Halomonas hydrothermalis (96.3 %), Halomonas gomseomensis (96.3 %), Halomonas venusta (96.3 %) and Halomonas meridiana (96.2 %). The major fatty acids of strain BH1(T) were C(18 : 1)ω7c (36.3 %), C(16 : 0) (18.4 %) and C(19 : 0) cyclo ω8c (17.9 %). The DNA G+C content was 60.0 mol% (T(m)). Ubiquinone 9 (Q-9) was the major lipoquinone. The phenotypic features, fatty acid profile and DNA G+C content further supported the placement of strain BH1(T) in the genus Halomonas. DNA-DNA hybridization values between strain BH1(T) and H. neptunia CECT 5815(T), H. variabilis DSM 3051(T), H. boliviensis DSM 15516(T) and H. sulfidaeris CECT 5817(T) were 19, 17, 30 and 29 %, respectively, supporting the differential taxonomic status of BH1(T). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain BH1(T) is considered to represent a novel species, for which the name Halomonas titanicae sp. nov. is proposed. The type strain is BH1(T) (=ATCC BAA-1257(T) =CECT 7585(T) =JCM 16411(T) =LMG 25388(T)).

  15. The expression of heterologous MAM-7 in Lactobacillus rhamnosus reduces its intrinsic capacity to inhibit colonization of pathogen Vibrio parahaemolyticus in vitro.

    Science.gov (United States)

    Beltran, Sebastian; Munoz-Bergmann, Cristian A; Elola-Lopez, Ana; Quintana, Javiera; Segovia, Cristopher; Trombert, Annette N

    2016-01-07

    Vibrio parahaemolyticus (V. parahaemolyticus) is a Gram-negative, halophilic bacterium recognized as one of the most important foodborne pathogen. When ingested, V. parahaemolyticus causes a self-limiting illness (Vibriosis), characterized mainly by watery diarrhoea. Treatment is usually oral rehydration and/or antibiotics in complicated cases. Since 1996, the pathogenic and pandemic V. parahaemolyticus O3:K6 serotype has spread worldwide, increasing the reported number of vibriosis cases. Thus, the design of new strategies for pathogen control and illness prevention is necessary. Lactobacillus sp. grouped Gram positive innocuous bacteria, part of normal intestinal microbiota and usually used as oral vaccines for several diarrheic diseases. Recombinants strains of Lactobacillus (RL) expressing pathogen antigens can be used as part of an anti-adhesion strategy where RL block the pathogen union sites in host cells. Thus, we aimed to express MAM-7 V. parahaemolyticus adhesion protein in Lactobacillus sp. to generate an RL that prevents pathogen colonization. We cloned the MAM-7 gene from V. parahaemolyticus RIMD 2210633 in Lactobacillus expression vectors. Recombinant strains (Lactobacillus rhamnosus pSEC-MAM7 and L. rhamnosus pCWA-MAM7) adhered to CaCo-2 cells and competed with the pathogen. However, the L. rhamnosus wild type strain showed the best capacity to inhibit pathogen colonization in vitro. In addition, LDH-assay showed that recombinant strains were cytotoxic compared with the wild type isogenic strain. MAM-7 expression in lactobacilli reduces the intrinsic inhibitory capacity of L. rhamnosus against V. parahaemolyticus.

  16. Lysinibacillus louembei sp. nov., a spore-forming bacterium isolated from Ntoba Mbodi, alkaline fermented leaves of cassava from the Republic of the Congo

    DEFF Research Database (Denmark)

    Ouoba, Labia Irène I.; Mbozo, Alain B. Vouidibio; Thorsen, Line

    2015-01-01

    . xylanilyticus DSM 23493T and L. odysseyi DSM 18869T was 41%, 16% and 15%, respectively. The internal transcribed spacer-PCR profile of the isolate was different from those of closely related bacteria. The cellwall peptidoglycan type was A4α, L-Lys-D-Asp and the major fatty acids were iso-C15:0, anteiso-C15......Investigation of the microbial diversity of Ntoba Mbodi, an African food made from the alkaline fermentation of cassava leaves, revealed the presence of a Gram-positive, catalase-positive, aerobic, motile and rod-shaped endospore-forming bacterium (NM73) with unusual phenotypic and genotypic......:0, anteiso-C17:0 and iso-C17:0 and iso-C17:1ω10c. The polar lipids included phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphoaminolipid, aminolipid, two phospholipids and two unknown lipids. The predominant menaquinones were MK-7 and MK-6.Ribose was the only whole-cell sugar...

  17. Useful halophilic, thermostable and ionic liquids tolerant cellulases

    Science.gov (United States)

    Zhang, Tao; Datta, Supratim; Simmons, Blake A.; Rubin, Edward M.

    2016-06-28

    The present invention provides for an isolated or recombinant polypeptide comprising an amino acid sequence having at least 70% identity with the amino acid sequence of a Halorhabdus utahensis cellulase, such as Hu-CBH1, wherein said amino acid sequence has a halophilic thermostable and/or thermophilic cellobiohydrolase (CBH) activity. In some embodiments, the polypeptide has a CBH activity that is resistant to up to about 20% of ionic liquids. The present invention also provides for compositions comprising and methods using the isolated or recombinant polypeptide.

  18. [Comparative analysis of clustered regularly interspaced short palindromic repeats (CRISPRs) loci in the genomes of halophilic archaea].

    Science.gov (United States)

    Zhang, Fan; Zhang, Bing; Xiang, Hua; Hu, Songnian

    2009-11-01

    Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a widespread system that provides acquired resistance against phages in bacteria and archaea. Here we aim to genome-widely analyze the CRISPR in extreme halophilic archaea, of which the whole genome sequences are available at present time. We used bioinformatics methods including alignment, conservation analysis, GC content and RNA structure prediction to analyze the CRISPR structures of 7 haloarchaeal genomes. We identified the CRISPR structures in 5 halophilic archaea and revealed a conserved palindromic motif in the flanking regions of these CRISPR structures. In addition, we found that the repeat sequences of large CRISPR structures in halophilic archaea were greatly conserved, and two types of predicted RNA secondary structures derived from the repeat sequences were likely determined by the fourth base of the repeat sequence. Our results support the proposal that the leader sequence may function as recognition site by having palindromic structures in flanking regions, and the stem-loop secondary structure formed by repeat sequences may function in mediating the interaction between foreign genetic elements and CAS-encoded proteins.

  19. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    KAUST Repository

    Balk, Melike

    2010-08-03

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts.

  20. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    KAUST Repository

    Balk, Melike; Mehboob, Farrakh; van Gelder, Antonie H; Rijpstra, W Irene C; Damsté , Jaap S Sinninghe; Stams, Alfons J M

    2010-01-01

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts.

  1. Use of magnetic beads for Gram staining of bacteria in aqueous suspension.

    Science.gov (United States)

    Yazdankhah, S P; Sørum, H; Larsen, H J; Gogstad, G

    2001-12-01

    A Gram staining technique was developed using monodisperse magnetic beads in concentrating bacteria in suspension for downstream application. The technique does not require heat fixation of organisms, electrical power, or a microscope. Gram-negative and Gram-positive bacteria were identified macroscopically based on the colour of the suspension. The bacteria concentrated on magnetic beads may also be identified microscopically.

  2. Gram-typing of mastitis bacteria in milk samples using flow cytometry

    DEFF Research Database (Denmark)

    Langerhuus, Sine Nygaard; Ingvartsen, Klaus Lønne; Bennedsgaard, Torben Werner

    2013-01-01

    Fast identification of pathogenic bacteria in milk samples from cows with clinical mastitis is central to proper treatment. In Denmark, time to bacterial diagnosis is typically 24 to 48 h when using traditional culturing methods. The PCR technique provides a faster and highly sensitive identifica......Fast identification of pathogenic bacteria in milk samples from cows with clinical mastitis is central to proper treatment. In Denmark, time to bacterial diagnosis is typically 24 to 48 h when using traditional culturing methods. The PCR technique provides a faster and highly sensitive...... cytometry-based method, which can detect and distinguish gram-negative and gram-positive bacteria in mastitis milk samples. The differentiation was based on bacterial fluorescence intensities upon labeling with biotin-conjugated wheat germ agglutinin and acridine orange. Initially 19 in-house bacterial...... characteristic curves for the 19 bacterial cultures. The method was then tested on 53 selected mastitis cases obtained from the department biobank (milk samples from 6 gram-negative and 47 gram-positive mastitis cases). Gram-negative bacteria in milk samples were detected with a sensitivity of 1...

  3. Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum

    Directory of Open Access Journals (Sweden)

    Furkan Orhan

    Full Text Available ABSTRACT In the current study, 18 halotolerant and halophilic bacteria have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture. The bacterial strains have been investigated for ammonia, indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate-deaminase production, phosphate solubilisation and nitrogen fixation activities. Of the tested bacteria, eight were inoculated with Triticum aestivum in a hydroponic culture. The investigated bacterial strains were found to have different plant-growth promoting activities in vitro. Under salt stress (200 mM NaCl, the investigated bacterial strains significantly increased the root and shoot length and total fresh weight of the plants. The growth rates of the plants inoculated with bacterial strains ranged from 62.2% to 78.1%.Identifying of novel halophilic and halotolerant bacteria that promote plant growth can be used as alternatives for salt sensitive plants. Extensive research has been conducted on several halophilic and halotolerant bacterial strains to investigate their plant growth promoting activities. However, to the best of my knowledge, this is the first study to inoculate these bacterial strains with wheat.

  4. Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum).

    Science.gov (United States)

    Orhan, Furkan

    2016-01-01

    In the current study, 18 halotolerant and halophilic bacteria have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture. The bacterial strains have been investigated for ammonia, indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate-deaminase production, phosphate solubilisation and nitrogen fixation activities. Of the tested bacteria, eight were inoculated with Triticum aestivum in a hydroponic culture. The investigated bacterial strains were found to have different plant-growth promoting activities in vitro. Under salt stress (200mM NaCl), the investigated bacterial strains significantly increased the root and shoot length and total fresh weight of the plants. The growth rates of the plants inoculated with bacterial strains ranged from 62.2% to 78.1%. Identifying of novel halophilic and halotolerant bacteria that promote plant growth can be used as alternatives for salt sensitive plants. Extensive research has been conducted on several halophilic and halotolerant bacterial strains to investigate their plant growth promoting activities. However, to the best of my knowledge, this is the first study to inoculate these bacterial strains with wheat. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  5. Incidence of carbapenem-resistant gram negatives in Italian transplant recipients: a nationwide surveillance study.

    Science.gov (United States)

    Lanini, Simone; Costa, Alessandro Nanni; Puro, Vincenzo; Procaccio, Francesco; Grossi, Paolo Antonio; Vespasiano, Francesca; Ricci, Andrea; Vesconi, Sergio; Ison, Michael G; Carmeli, Yehuda; Ippolito, Giuseppe

    2015-01-01

    Bacterial infections remain a challenge to solid organ transplantation. Due to the alarming spread of carbapenem-resistant gram negative bacteria, these organisms have been frequently recognized as cause of severe infections in solid organ transplant recipients. Between 15 May and 30 September 2012 we enrolled 887 solid organ transplant recipients in Italy with the aim to describe the epidemiology of gram negative bacteria spreading, to explore potential risk factors and to assess the effect of early isolation of gram negative bacteria on recipients' mortality during the first 90 days after transplantation. During the study period 185 clinical isolates of gram negative bacteria were reported, for an incidence of 2.39 per 1000 recipient-days. Positive cultures for gram negative bacteria occurred early after transplantation (median time 26 days; incidence rate 4.33, 1.67 and 1.14 per 1,000 recipient-days in the first, second and third month after SOT, respectively). Forty-nine of these clinical isolates were due to carbapenem-resistant gram negative bacteria (26.5%; incidence 0.63 per 1000 recipient-days). Carbapenems resistance was particularly frequent among Klebsiella spp. isolates (49.1%). Recipients with longer hospital stay and those who received either heart or lung graft were at the highest risk of testing positive for any gram negative bacteria. Moreover recipients with longer hospital stay, lung recipients and those admitted to hospital for more than 48h before transplantation had the highest probability to have culture(s) positive for carbapenem-resistant gram negative bacteria. Forty-four organ recipients died (0.57 per 1000 recipient-days) during the study period. Recipients with at least one positive culture for carbapenem-resistant gram negative bacteria had a 10.23-fold higher mortality rate than those who did not. The isolation of gram-negative bacteria is most frequent among recipient with hospital stays >48 hours prior to transplant and in those

  6. Incidence of carbapenem-resistant gram negatives in Italian transplant recipients: a nationwide surveillance study.

    Directory of Open Access Journals (Sweden)

    Simone Lanini

    Full Text Available Bacterial infections remain a challenge to solid organ transplantation. Due to the alarming spread of carbapenem-resistant gram negative bacteria, these organisms have been frequently recognized as cause of severe infections in solid organ transplant recipients.Between 15 May and 30 September 2012 we enrolled 887 solid organ transplant recipients in Italy with the aim to describe the epidemiology of gram negative bacteria spreading, to explore potential risk factors and to assess the effect of early isolation of gram negative bacteria on recipients' mortality during the first 90 days after transplantation. During the study period 185 clinical isolates of gram negative bacteria were reported, for an incidence of 2.39 per 1000 recipient-days. Positive cultures for gram negative bacteria occurred early after transplantation (median time 26 days; incidence rate 4.33, 1.67 and 1.14 per 1,000 recipient-days in the first, second and third month after SOT, respectively. Forty-nine of these clinical isolates were due to carbapenem-resistant gram negative bacteria (26.5%; incidence 0.63 per 1000 recipient-days. Carbapenems resistance was particularly frequent among Klebsiella spp. isolates (49.1%. Recipients with longer hospital stay and those who received either heart or lung graft were at the highest risk of testing positive for any gram negative bacteria. Moreover recipients with longer hospital stay, lung recipients and those admitted to hospital for more than 48h before transplantation had the highest probability to have culture(s positive for carbapenem-resistant gram negative bacteria. Forty-four organ recipients died (0.57 per 1000 recipient-days during the study period. Recipients with at least one positive culture for carbapenem-resistant gram negative bacteria had a 10.23-fold higher mortality rate than those who did not.The isolation of gram-negative bacteria is most frequent among recipient with hospital stays >48 hours prior to transplant

  7. Ribulose 1,5-bisphosphate dependent CO2 fixation in the halophilic archaebacterium, Halobacterium mediterranei

    International Nuclear Information System (INIS)

    Rawal, N.; Kelkar, S.M.; Altekar, W.

    1988-01-01

    The cell extract of Halobacterium mediterranei catalyses incorporation of 14 CO 2 into 3-phosphoglycerate in the presence of ribulose bisphosphate suggesting the existence of ribulose bisphosphate carboxylase activity in this halophilic archaebacterium

  8. Halophilic-Psychrophilic Bacteria from Tirich Mir Glacier, Pakistan, as Potential Candidate for Astrobiological Studies

    Science.gov (United States)

    Rafiq, M. R.; Anesio, A. M. A.; Hayat, M. H.; Zada, S. Z.; Sajjad, W. S.; Shah, A. A. S.; Hasan, F. H.

    2016-09-01

    Hindu Kush, Karakoram, and Himalaya region is referred to as 'third pole' and could be suitable as a terrestrial analog of Mars and increased possibility of finding polyextremophiles. Study is focused on halophilic psychrophiles.

  9. Comparative in vitro activities of trovafloxacin (CP-99,219) against 445 gram-positive isolates from patients with endocarditis and those with other bloodstream infections

    NARCIS (Netherlands)

    H.P. Endtz (Hubert); J.W. Mouton (Johan); J.G. den Hollander (Jan); N.P.W.C.J. van den Braak (Nicole); H.A. Verbrugh (Henri)

    1997-01-01

    textabstractThe in vitro activity of trovafloxacin (CP-99,219), a new fluoroquinolone, was compared with the in vitro activities of other commonly used quinolones and other antimicrobial agents against 445 gram-positive microorganisms isolated between 1986 and 1995 from

  10. Bacterioruberin and salinixanthin carotenoids of extremely halophilic Archaea and Bacteria: A Raman spectroscopic study

    Science.gov (United States)

    Jehlička, J.; Edwards, H. G. M.; Oren, A.

    2013-04-01

    Laboratory cultures of a number of red extremely halophilic Archaea (Halobacterium salinarum strains NRC-1 and R1, Halorubrum sodomense, Haloarcula valismortis) and of Salinibacter ruber, a red extremely halophilic member of the Bacteria, have been investigated by Raman spectroscopy using 514.5 nm excitation to characterize their carotenoids. The 50-carbon carotenoid α-bacterioruberin was detected as the major carotenoid in all archaeal strains. Raman spectroscopy also detected bacterioruberin as the main pigment in a red pellet of cells collected from a saltern crystallizer pond. Salinibacter contains the C40-carotenoid acyl glycoside salinixanthin (all-E, 2'S)-2'-hydroxy-1'-[6-O-(methyltetradecanoyl)-β-D-glycopyranosyloxy]-3',4'-didehydro-1',2'-dihydro-β,ψ-carotene-4-one), for which the Raman bands assignments of are given here for the first time.

  11. [Isolation and identification of a lactate-utilizing, butyrate-producing bacterium and its primary metabolic characteristics].

    Science.gov (United States)

    Liu, Wei; Zhu, Wei-yun; Yao, Wen; Mao, Sheng-yong

    2007-06-01

    The distal mammalian gut harbors prodigiously abundant microbes, which provide unique metabolic traits to host. A lactate-utilizing, butyrate-producing bacterium, strain LB01, was isolated from adult swine feces by utilizing modified Hungate technique with rumen liquid-independent YCFA medium supplemented with lactate as the single carbon source. It was an obligate anaerobic, Gram positive bacterium, and could utilize glucose, fructose, maltose and lactate with a large amount of gas products. 16S rRNA sequence analysis revealed that it had the high similarity with members of the genus Megasphaera. The metabolic characteristics of strain LB01 was investigated by using in vitro fermentation system. Lactate at the concentration of 65 mmol/L in YCFA medium was rapidly consumed within 9 hours and was mainly converted to propionate and butyrate after 24h. As the level of acetate declined, the concentration of butyrate rose only in the presence of glucose, suggesting that butyrate could possibly be synthesized by the acetyl CoA: butyryl CoA transferase. When co-cultured with lactic acid bacteria strain K9, strain LB01 evidently reduced the concentration of lactate produced by strain K9 and decelerated the rapid pH drop, finally producing 12.11 mmol/L butyrate and 4.06 mmol/L propionate. The metabolic characteristics that strain LB01 efficiently converts toxic lactate and excessive acetate to butyrate can prevent lactate and acetate accumulation in the large intestine and maintain the slightly acidic environment of the large intestine, consequently revealing that stain LB01 could act as a potential probiotics.

  12. Monograph: In vitro efficacy of 30 ethnomedicinal plants used by Indian aborigines against 6 multidrug resistant Gram-positive pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Mahesh Chandra Sahu

    2015-02-01

    Full Text Available Objective: To monitor in vitro antibacterial activities of leaf extracts of 30 common and noncommon plants used by aborigines in Kalahandi district, Odisha, against 6 clinically isolated multidrug resistant (MDR Gram-positive bacteria of 3 genera, Staphylococcus, Streptococcus, and Enterococcus. Methods: The antibiotic sensitivity patterns of 6 bacterial strains were studied with the diskdiffusion method with 1 7 antibiotics belonging to 8 classes. Monitored plants have ethnomedicinal use and several are used as traditional medicines. Antibacterial properties were studied with the agar-well diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration values of ethanolic and aqueous extracts of plants were determined by the microbroth-dilution method. Results: Ethanolic plant-extracts had the better antibacterial potencies in comparison to their corresponding aqueous extracts. Plants with most conspicuous antibacterial properties in controlling MDR strains of Gram-positive bacteria were aqueous and ethanolic extracts of plants, Ixora coccinea, Nyctanthes arbor-tristis, Polycythaemia rubra, Pongamia pinnata and Syzygium cumini, Carthamus tinctorius, Cucurbita maxima, Murraya koenigii, Leucas aspera, Plumbago indica and Psidium guajava. Ethanolic extracts of most plants had phytochemicals, alkaloids, glycosides, terpenoids, reducing sugars, saponins, tannins, flavonoids and steroids. Conclusions: These plants could be used further for the isolation of pure compounds to be used as complementary non-microbial antimicrobial medicines.

  13. Identification of the sigmaB regulon of Bacillus cereus and conservation of sigmaB-regulated genes in low-GC-content gram-positive bacteria

    NARCIS (Netherlands)

    Schaik, van W.; Voort, van der M.; Molenaar, D.; Moezelaar, R.; Vos, de W.M.; Abee, T.

    2007-01-01

    The alternative sigma factor B has an important role in the acquisition of stress resistance in many gram-positive bacteria, including the food-borne pathogen Bacillus cereus. Here, we describe the identification of the set of B-regulated genes in B. cereus by DNA microarray analysis of the

  14. Biodeterioration Risk Threatens the 3100 Year Old Staircase of Hallstatt (Austria): Possible Involvement of Halophilic Microorganisms.

    Science.gov (United States)

    Piñar, Guadalupe; Dalnodar, Dennis; Voitl, Christian; Reschreiter, Hans; Sterflinger, Katja

    2016-01-01

    The prosperity of Hallstatt (Salzkammergut region, Austria) is based on the richness of salt in the surrounding mountains and salt mining, which is documented as far back as 1500 years B.C. Substantial archaeological evidence of Bronze and Iron Age salt mining has been discovered, with a wooden staircase (1108 B.C.) being one of the most impressive and well preserved finds. However, after its discovery, fungal mycelia have been observed on the surface of the staircase, most probably due to airborne contamination after its find. As a basis for the further preservation of this valuable object, the active micro-flora was examined to investigate the presence of potentially biodegradative microorganisms. Most of the strains isolated from the staircase showed to be halotolerant and halophilic microorganisms, due to the saline environment of the mine. Results derived from culture-dependent assays revealed a high fungal diversity, including both halotolerant and halophilic fungi, the most dominant strains being members of the genus Phialosimplex (synonym: Aspergillus). Additionally, some typical cellulose degraders, namely Stachybotrys sp. and Cladosporium sp. were detected. Numerous bacterial strains were isolated and identified as members of 12 different genera, most of them being moderately halophilic species. The most dominant isolates affiliated with species of the genera Halovibrio and Marinococcus. Halophilic archaea were also isolated and identified as species of the genera Halococcus and Halorubrum. Molecular analyses complemented the cultivation assays, enabling the identification of some uncultivable archaea of the genera Halolamina, Haloplanus and Halobacterium. Results derived from fungi and bacteria supported those obtained by cultivation methods, exhibiting the same dominant members in the communities. The results clearly showed the presence of some cellulose degraders that may become active if the requirements for growth and the environmental conditions

  15. Biodeterioration Risk Threatens the 3100 Year Old Staircase of Hallstatt (Austria: Possible Involvement of Halophilic Microorganisms.

    Directory of Open Access Journals (Sweden)

    Guadalupe Piñar

    Full Text Available The prosperity of Hallstatt (Salzkammergut region, Austria is based on the richness of salt in the surrounding mountains and salt mining, which is documented as far back as 1500 years B.C. Substantial archaeological evidence of Bronze and Iron Age salt mining has been discovered, with a wooden staircase (1108 B.C. being one of the most impressive and well preserved finds. However, after its discovery, fungal mycelia have been observed on the surface of the staircase, most probably due to airborne contamination after its find.As a basis for the further preservation of this valuable object, the active micro-flora was examined to investigate the presence of potentially biodegradative microorganisms.Most of the strains isolated from the staircase showed to be halotolerant and halophilic microorganisms, due to the saline environment of the mine. Results derived from culture-dependent assays revealed a high fungal diversity, including both halotolerant and halophilic fungi, the most dominant strains being members of the genus Phialosimplex (synonym: Aspergillus. Additionally, some typical cellulose degraders, namely Stachybotrys sp. and Cladosporium sp. were detected. Numerous bacterial strains were isolated and identified as members of 12 different genera, most of them being moderately halophilic species. The most dominant isolates affiliated with species of the genera Halovibrio and Marinococcus. Halophilic archaea were also isolated and identified as species of the genera Halococcus and Halorubrum. Molecular analyses complemented the cultivation assays, enabling the identification of some uncultivable archaea of the genera Halolamina, Haloplanus and Halobacterium. Results derived from fungi and bacteria supported those obtained by cultivation methods, exhibiting the same dominant members in the communities.The results clearly showed the presence of some cellulose degraders that may become active if the requirements for growth and the environmental

  16. Antimicrobial susceptibility of quinupristin/dalfopristin tested against gram-positive cocci from Latin America: results from the Global SMART (GSMART surveillance study

    Directory of Open Access Journals (Sweden)

    Sader Helio S.

    2001-01-01

    Full Text Available Gram-positive cocci are important causes of both nosocomial and community-acquired infections, and antimicrobial resistance among these pathogens has become an important problem worldwide. Since resistance among these organisms can vary substantially by geographic location, we conducted a multicenter surveillance study with isolates from five Latin American countries (15 medical centers. Quinupristin/dalfopristin (formerly RP-59500 is a novel streptogramin combination with focused activity against Gram-positive cocci, many exhibiting emerging resistance. The in vitro activity of quinupristin/dalfopristin and 12 other antimicrobial agents were evaluated against 1,948 strains including Staphylococcus aureus (747 strains, coagulase-negative staphylococci (CoNS; 446 strains, enterococci (429 strains, and various Streptococcus spp. (326 strains. Oxacillin resistance was observed in 41% of S. aureus (MIC, or = 13 mm and 40% of CoNS (MIC, or = 18 mm. Vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90, 0.25 - 1 mug/ml remained effective against all strains, but cross-resistance was high among other tested drugs. The quinupristin/dalfopristin MIC50 for Streptococcus pneumoniae and other streptococci was only 0.5 mug/ml (13% to 28% were penicillin-resistant; 12% to 22% were macrolide-resistant. Enterococci demonstrated variable inhibition by quinupristin/dalfopristin depending upon identification and the susceptibility testing method used. The demonstrated quinupristin/dalfopristin activity against Enterococcus faecium was confirmed, but potential species identification errors with various commercial systems continue to confuse susceptibility statistics, even though some strains of E. faecium confirmed by PCR-based or other molecular identification techniques did have quinupristin/dalfopristin MICs of > or = 4 mug/mL. Most important, glycopeptide-resistant enterococci are rapidly emerging in Latin America, and quinupristin/dalfopristin appears

  17. A molecular gram stain using broad range PCR and pyrosequencing technology: a potentially useful tool for diagnosing orthopaedic infections.

    Science.gov (United States)

    Kobayashi, Naomi; Bauer, Thomas W; Togawa, Daisuke; Lieberman, Isador H; Sakai, Hiroshige; Fujishiro, Takaaki; Tuohy, Marion J; Procop, Gary W

    2005-06-01

    The bacteria associated with orthopaedic infections are usually common gram-positive and gram-negative bacteria. This fundamental grouping of bacteria is a necessary first step in the selection of appropriate antibiotics. Since polymerase chain reaction (PCR) is more rapid and may be more sensitive than culture, we developed a postamplification pyrosequencing method to subcategorize bacteria based on a few nucleotide polymorphisms in the 16S rRNA gene. We validated this method using well-characterized strains of bacteria and applied it to specimens from spinal surgery cases with suspected infections. Lysates of 114 bacteria including 75 species were created following standard cultivation to obtain DNA. The DNA was amplified by a broad-range real-time PCR. The amplicons were evaluated by pyrosequencing and were classified as gram-positive, gram-negative, or acid-fast bacilli based on the first three to five nucleotides sequenced. In addition, clinical cases of suspected infection were obtained from spinal surgery. The results of the "molecular Gram stain" were compared with the results of traditional Gram stain and culture. The lysates of 107 (93.9%) of the bacteria extracts tested were appropriately categorized as gram-positive and gram-negative or as acid-fast bacilli on the basis of this assay. The sensitivity and specificity of this assay were 100% and 97.4% for gram-positive and 88.3% and 100% for gram-negative isolates. All of the five clinical samples were appropriately categorized as containing gram-positive or gram-negative bacteria with this assay. This study demonstrates that high sensitivity and specificity of a molecular gram stain may be achieved using broad-range real-time PCR and pyrosequencing.

  18. Characterization and Discrimination of Gram-Positive Bacteria Using Raman Spectroscopy with the Aid of Principal Component Analysis

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    Alia Colniță

    2017-09-01

    Full Text Available Raman scattering and its particular effect, surface-enhanced Raman scattering (SERS, are whole-organism fingerprinting spectroscopic techniques that gain more and more popularity in bacterial detection. In this work, two relevant Gram-positive bacteria species, Lactobacillus casei (L. casei and Listeria monocytogenes (L. monocytogenes were characterized based on their Raman and SERS spectral fingerprints. The SERS spectra were used to identify the biochemical structures of the bacterial cell wall. Two synthesis methods of the SERS-active nanomaterials were used and the recorded spectra were analyzed. L. casei and L. monocytogenes were successfully discriminated by applying Principal Component Analysis (PCA to their specific spectral data.

  19. Detection, cloning and bioinformatics analysis of vip1/vip2 genes ...

    African Journals Online (AJOL)

    Bio-insecticides based on the spore forming bacterium, Bacillus thuringiensis (Bt) have been used for commercial scale for the past 40 years. Bt is a Gram-positive soil bacterium that forms insecticidal crystal proteins (ICPs) during sporulation; it has been characterized as an insect pathogen. Vegetative insecticidal protein ...

  20. Global transcriptome analysis of Halolamina sp. to decipher the salt tolerance in extremely halophilic archaea.

    Science.gov (United States)

    Kurt-Kızıldoğan, Aslıhan; Abanoz, Büşra; Okay, Sezer

    2017-02-15

    Extremely halophilic archaea survive in the hypersaline environments such as salt lakes or salt mines. Therefore, these microorganisms are good sources to investigate the molecular mechanisms underlying the tolerance to high salt concentrations. In this study, a global transcriptome analysis was conducted in an extremely halophilic archaeon, Halolamina sp. YKT1, isolated from a salt mine in Turkey. A comparative RNA-seq analysis was performed using YKT1 isolate grown either at 2.7M NaCl or 5.5M NaCl concentrations. A total of 2149 genes were predicted to be up-regulated and 1638 genes were down-regulated in the presence of 5.5M NaCl. The salt tolerance of Halolamina sp. YKT1 involves the up-regulation of genes related with membrane transporters, CRISPR-Cas systems, osmoprotectant solutes, oxidative stress proteins, and iron metabolism. On the other hand, the genes encoding the proteins involved in DNA replication, transcription, translation, mismatch and nucleotide excision repair were down-regulated. The RNA-seq data were verified for seven up-regulated genes as well as six down-regulated genes via qRT-PCR analysis. This comprehensive transcriptome analysis showed that the halophilic archaeon canalizes its energy towards keeping the intracellular osmotic balance minimizing the production of nucleic acids and peptides. Copyright © 2016 Elsevier B.V. All rights reserved.