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Sample records for producing strain pcc7820

  1. Organic metabolites produced by Vibrio parahaemolyticus strain ...

    African Journals Online (AJOL)

    Identification and action of several antibacterial metabolites produced by a fish pathogen Vibrio parahaemolyticus strain An3 from marine ecosystem of Goa has been demonstrated. Antibacterial activity of the crude cell extract of the test bacterium has been evaluated against indicator pathogenic bacterial strains such as ...

  2. [New antibiotics produced by Bacillus subtilis strains].

    Science.gov (United States)

    Malanicheva, I A; Kozlov, D G; Efimenko, T A; Zenkova, V A; Kastrukha, G S; Reznikova, M I; Korolev, A M; Borshchevskaia, L N; Tarasova, O D; Sineokiĭ, S P; Efremenkova, O V

    2014-01-01

    Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mes6nteroides VKPM B-4177 resistant to glycopep-> tide antibiotics, as well as antifungal activity. The strains were identified as belonging to the "B. subtilis" com- plex based on their morphological and physiological characteristics, as well as by sequencing of the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaen and pentaen, respectively). Strain INA 01086 produced also a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.

  3. New rifamycins produced by a recombinant strain of Nocardia mediterranei.

    Science.gov (United States)

    Schupp, T; Traxler, P; Auden, J A

    1981-08-01

    A recombinant strain of Nocardia mediterranei was found to produce a number of new rifamycins which are structurally related to rifamycin S, rifamycin W and rifamycin G. This strain was derived from two Nocardia mediterranei mutants by intraspecific recombination.

  4. Construction of acetoin high-producing Bacillus subtilis strain

    Directory of Open Access Journals (Sweden)

    Yanjun Tian

    2016-07-01

    Full Text Available This paper describes the construction and selection of a high-producing mutant, Bacillus subtilis HB-32, with enhanced acetoin yield and productivity. The mutant was obtained by the protoplast fusion of a Bacillus subtilis mutant TH-49 (Val− producing acetoin and Bacillus licheniformis AD-30 producing α-acetolactate decarboxylase, with the fusogen polyethylene glycol and after the regeneration and selection, etc. of the fusant. The acetoin production reached 49.64 g/L, which is an increase of 61.8% compared to that of B. subtilis strain TH-49. Random amplified polymorphic DNA analysis was performed to determine the mutagenic and protoplast fusion effects and the genomic changes in the acetoin high-producing strain compared to the parent strains at the molecular level. The constructed strain was shown to be promising for large-scale acetoin production. Future studies should focus on the application of the mutant strain in practice.

  5. Competitive Dominance by a Bacteriocin-Producing Vibrio harveyi Strain.

    Science.gov (United States)

    Hoyt, P R; Sizemore, R K

    1982-09-01

    Vibrio (Beneckea) harveyi, a bioluminescent marine bacterium, has been shown to produce a bacteriocin-like substance the production of which is mediated by a plasmid. This substance is assumed to be proteinaceous because of its sensitivity to certain proteolytic enzymes. It is stable at low temperatures and can be concentrated by ammonium sulfate precipitation or negative-pressure dialysis. The molecular weight of the bacteriocin was determined to be 2.4 x 10 by molecular exclusion chromatography. Competition experiments indicated that bacteriocin-producing strains predominated over cured variants of the same strain in broth culture experiments. We studied several environmental parameters (pH, salinity, temperature, nutrient concentration) to determine their effects on the competitive advantage bestowed on a bacteriocin-producing strain. Under simulated free-living conditions, no competitive advantage attributable to bacteriocin production was observed. In a simulated enteric habitat, a bacteriocin-producing strain showed dramatic (>90%) inhibition of the sensitive strain within 24 h.

  6. Isolation and characterization of lipase-producing Bacillus strains ...

    African Journals Online (AJOL)

    Bacillus strains (B1 - B5) producing extra cellular lipase were isolated from the soil sample of coconut oil industry. The strains were identified by morphological and biochemical characters. Growth of the organisms and lipase production were measured with varying pH (4 - 9) temperature (27, 37 and 47ºC) and various ...

  7. Aflatoxin B1 producing potential of Aspergillus flavus strains isolated ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-07-20

    Jul 20, 2009 ... consumption of aflatoxin contaminated food and feed. (Reddy and ..... intervals by artificial inoculation of A. parasiticus on rice grains. ... additive for culture media for rapid identification of aflatoxin producing. Aspergillus strains ...

  8. NEW PRODUCER STRAINS OF BIOBUTANOL. І. ISOLATION AND IDENTIFICATION

    Directory of Open Access Journals (Sweden)

    O. A. Tigunova

    2013-02-01

    Full Text Available Getting new, more productive strains of microorganisms that produce butanol is a topical problem. Studing of morphological and physiological characteristics of the isolated strains, improvement of their cultivation conditions, optimization of biobutanol synthesis gives the possibility to organize a cost-effective butanol production technology. The aim of this work was searching new butanol and butyric acid producer strains, their identification and studying the main steps of the selective strains biosynthesis. The objects of this study were microorganisms that had allocated from soils and sludges samples of Kiev’s lakes. Obtained cultures have been screened. Three strains were obtained as promising and identified as C. acetobutylicum, C. tyrobutylicum, C. butylicum. Selective medium have been developed and modified for the microorganisms. Producer’s features were investigated in order to maximize the accumulation of target metabolites.

  9. Antimicrobial properties of Pseudomonas strains producing the antibiotic mupirocin.

    Science.gov (United States)

    Matthijs, Sandra; Vander Wauven, Corinne; Cornu, Bertrand; Ye, Lumeng; Cornelis, Pierre; Thomas, Christopher M; Ongena, Marc

    2014-10-01

    Mupirocin is a polyketide antibiotic with broad antibacterial activity. It was isolated and characterized about 40 years ago from Pseudomonas fluorescens NCIMB 10586. To study the phylogenetic distribution of mupirocin producing strains in the genus Pseudomonas a large collection of Pseudomonas strains of worldwide origin, consisting of 117 Pseudomonas type strains and 461 strains isolated from different biological origins, was screened by PCR for the mmpD gene of the mupirocin gene cluster. Five mmpD(+) strains from different geographic and biological origin were identified. They all produced mupirocin and were strongly antagonistic against Staphylococcus aureus. Phylogenetic analysis showed that mupirocin production is limited to a single species. Inactivation of mupirocin production leads to complete loss of in vitro antagonism against S. aureus, except on certain iron-reduced media where the siderophore pyoverdine is responsible for the in vitro antagonism of a mupirocin-negative mutant. In addition to mupirocin some of the strains produced lipopeptides of the massetolide group. These lipopeptides do not play a role in the observed in vitro antagonism of the mupirocin producing strains against S. aureus. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  10. Lichenysin is produced by most Bacillus licheniformis strains.

    Science.gov (United States)

    Madslien, E H; Rønning, H T; Lindbäck, T; Hassel, B; Andersson, M A; Granum, P E

    2013-10-01

    The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml(-1) , which is in accordance with previous studies. This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive. © 2013 The Society for Applied Microbiology.

  11. LYOPHILIZATION EFFECT ON PRODUCTIVITY OF BUTANOL-PRODUCING STRAINS

    Directory of Open Access Journals (Sweden)

    O. O. Tigunova

    2016-10-01

    Full Text Available Investigation of lyophilization effect on the productivity of butanol-producing strains was the aim of our research. For this purpose we used butanol-producing strains; technical glycerol; biomass of switchgrass Panicum virgatum L. Lyophilization was performed using a lyophilization-drying. The effect of the protective medium on residual moisture of freezedrying cultures suspensions depending on the concentration of glucose and sucrose was studed. It was shown that the lowest residual moisture was attained by using glucose and sucrose in amount of 10% and if the samples of freeze-drying bacteria had been saved for one month at 4 οC the productivity did not decrease. As temperature preservation was increased the productivity of the cultures was gradually decreased and it was greatly reduced at 30 οC. So the protective medium composition was optimized for lyophilization of butanol-producing strains as follows: sucrose 10.0%; gelatin 10.0%; agar 0.02%. It was shown that the preservation of samples of freeze-drying bacteria for six months at a temperature of 4 οC did not affect the productivity of strains. It was found that cultures could use glycerol as a carbon source for butanol accumulation before lyophilization.

  12. DOMESTIC BUTANOL-PRODUCING STRAINS OF THE Clostridium GENUS

    Directory of Open Access Journals (Sweden)

    O. O. Tigunova

    2017-02-01

    Full Text Available The aim of the work was to summarize the results of own research concerning obtaining butanol producing strains of Clostridium genus, to identify them by physiological, morphological and genetic methods. Further study of characteristics and biological features of the strains, and various approaches in biotechnological process of butanol production are discussed. The work includes methods to increase butanol accumulation by producer strains. Perspectives of using chemical mutagenesis in Clostridia as a method of increasing butanol production are considered. The feasibility of using non-food raw material as a substrate for fermentation is discussed. Different methods of pretreatment and their impact on the accumulation of butanol in the liquid medium are compared. Butanol accumulation is shown to increase significantly if the synthesis precursors are added as components of enzymatic medium, and the “reverse bard” is used to reduce waste production without affecting the level of butanol synthesis. The problem of conservation of producing strains is given, and protective medium for microorganisms during the freeze-drying is defined.

  13. Selection of tannase-producing Aspergillus niger strains

    OpenAIRE

    Pinto,Gustavo A.S.; Leite,Selma G.F.; Terzi,Selma C.; Couri,Sonia

    2001-01-01

    The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g-1/72 hours of fermentation).

  14. Growth characteristics and enzyme production optimization of lipase Producing Strain

    Science.gov (United States)

    Zheng, Chaocheng

    2018-01-01

    55 samples from different regions were selected and screened by Rhodamine B flat transparent circle method to observe lipase producing effect, among which, LHY-1, identified as Serratia sp. has the characteristics of fast growth, high enzyme production and stable ability. The colony of this strain is white, the edge is smooth and tidy, the surface is moist, the cell is straight, rod-shaped, gram negative, 0.1-0.2 μm in diameter and, length 0.3-0.5 μm in length.

  15. Bacillus amyloliquefaciens SUBSP. plantarum PROBIOTIC STRAINS AS PROTEASE PRODUCERS

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    E. V. Маtseliukh

    2015-04-01

    Full Text Available Proteases from probiotic strains of the genus Bacillus, just like the antibiotics, bacteriocins and other hydrolytic enzymes, are one of the main factors that determine their biological activity. The aim of this work was to study the synthesis and biochemical properties of proteases from two strains Bacillus amyloliquefaciens subsp. plantarum UCM B-5139 and UCM B-5140 that included in the probiotic Endosporin. The cultivation of strains was carried out in flasks under rotating for two days. The influence of physico-chemical parameters of the reaction medium on proteolytic activity was studied on partially purified protease preparations. Lytic activity was determined by turbidimetric method. On the second day of cultivation B. amyloliquefaciens subsp. plantarum UCM В-5139 and UCM В-5140 synthesized the metal-dependent peptidase and serine protease, respectively. The optimum conditions of their action were the following: temperature 37–40 °C and pH 6.5–7.0. Isolated proteases are able to lyse the living cells of Staphylococcus aureus and Candida albicans. Thus we demonstrated that B. amyloliquefaciens subsp. plantarum UCM B-5140 and UCM B-5139, included in the probiotic veterinary preparation Endosporin, produced proteolytic enzymes that hydrolyze the native insoluble proteins (elastin, fibrin and collagen. These enzymes belong to the group of neutral metal-dependent and serine proteases. They are active under physiological conditions against gram-positive bacteria and yeasts. The application of these proteases in biotechnology is considered.

  16. Genetic Diversity Among Botulinum Neurotoxin Producing Clostridial Strains

    Energy Technology Data Exchange (ETDEWEB)

    Hill, K K; Smith, T J; Helma, C H; Ticknor, L O; Foley, B T; Svennson, R T; Brown, J L; Johnson, E A; Smith, L A; Okinaka, R T; Jackson, P J; Marks, J D

    2006-07-06

    Clostridium botulinum is a taxonomic designation for many diverse anaerobic spore forming rod-shaped bacteria which have the common property of producing botulinum neurotoxins (BoNTs). The BoNTs are exoneurotoxins that can cause severe paralysis and even death in humans and various other animal species. A collection of 174 C. botulinum strains were examined by amplified fragment length polymorphism (AFLP) analysis and by sequencing of the 16S rRNA gene and BoNT genes to examine genetic diversity within this species. This collection contained representatives of each of the seven different serotypes of botulinum neurotoxins (BoNT A-G). Analysis of the16S rRNA sequences confirmed earlier reports of at least four distinct genomic backgrounds (Groups I-IV) each of which has independently acquired one or more BoNT serotypes through horizontal gene transfer. AFLP analysis provided higher resolution, and can be used to further subdivide the four groups into sub-groups. Sequencing of the BoNT genes from serotypes A, B and E in multiple strains confirmed significant sequence variation within each serotype. Four distinct lineages within each of the BoNT A and B serotypes, and five distinct lineages of serotype E strains were identified. The nucleotide sequences of the seven serotypes of BoNT were compared and show varying degrees of interrelatedness and recombination as has been previously noted for the NTNH gene which is linked to BoNT. These analyses contribute to the understanding of the evolution and phylogeny within this species and assist in the development of improved diagnostics and therapeutics for treatment of botulism.

  17. Effect of ropy and capsular exopolysaccharides producing strain of ...

    African Journals Online (AJOL)

    The contribution of selected ropy and capsular Lactobacillus plantarum 162RM on texture of fermented milk as well as on the functionality of kareish cheese was established in this study. The cell suspension of this strain was used in combination with commercial starter cultures MY900 (Lactobacillus delbrueckii ssp.

  18. Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

    NARCIS (Netherlands)

    Geel-Schutten, G.H. van; Flesch, F.; Brink, B. ten; Smith, M.R.; Dijkhuizen, L.

    1998-01-01

    A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent

  19. Safety Evaluation of Enterocin Producer Enterococcus sp. Strains Isolated from Traditional Turkish Cheeses.

    Science.gov (United States)

    Avcı, Mine; Özden Tuncer, Banu

    2017-07-06

    The purpose of this study was to determine the antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. isolated from different cheeses and also investigate some of their virulence factors. Enterococcus strains were isolated from 33 different cheeses. Enterococcus faecium (6 strains) and Enterococcus faecalis (5 strains) enterocin-producing strains were identified by 16S rDNA analyses. Structural genes entA, entB, entP and entX were detected in some isolates. Multiple enterocin structural genes were found in 7 strains. None of the tested enterococci demonstrated anyβ-haemolytic activity and only one strain had gelatinase activity. Six strains showed multiple antibiotic resistance patterns and in addition, vanA and several virulence genes were detected in many strains. Only E. faecalis MBE1-9 showed tyrosine decarboxylase activity and tdc gene was detected only in this strain.

  20. Apparatus Producing an Even Distribution of Strain into Carries

    Science.gov (United States)

    Hrabovský, Leopold

    2017-10-01

    In many high-rise residential buildings or multi-storey warehouses, machinery, so called lifts, is used for the vertical transportation of people or weights between two or more altitudinally distant places. Carriers used for lifts are steel ropes or sprocket chains, on which a cage or a counterbalance is hinged. Apparatus of all carriers, attached to the hinge of the cage or counterbalance, should be even. This can be made only by hammer hinge. Fixed or springe hinge cannot be a perfect equalizing apparatus. This article describes an apparatus, which allows an even distribution of the strain into lift carriers, which use springe hinge of carrier ropes.

  1. Screening on the high yield validamycin producing strain by implantation with N+ and Ti+ ion source

    International Nuclear Information System (INIS)

    Yu Long; An Xiao

    2007-01-01

    In order to compared the mutagenic effects of the validamycin producing the strain (Streptomyces hygroscopicus var. Jingganggensis Yen.) was implanted with two kinds of ion sources. The results showed that when two kinds of ion sources implanted into the strain by turns, more positive mutants and higher yield would be acquired. Using this method, a high-yielding strain B1-3 was obtained, which produce the titer of validamycin A of 21514, and was 54.4% higher than that of the original strain. (authors)

  2. Divergence in wine characteristics produced by wild and domesticated strains of Saccharomyces cerevisiae

    Science.gov (United States)

    Hyma, Katie E; Saerens, Sofie M; Verstrepen, Kevin J; Fay, Justin C

    2011-01-01

    The budding yeast Saccharomyces cerevisiae is the primary species used by wine makers to convert sugar into alcohol during wine fermentation. Saccharomyces cerevisiae is found in vineyards, but is also found in association with oak trees and other natural sources. Although wild strains of S. cerevisiae as well as other Saccharomyces species are also capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine, consistent with the idea that wine making strains have been domesticated for wine production. In this study, we demonstrate that humans can distinguish between wines produced using wine strains and wild strains of S. cerevisiae as well as its sibling species, Saccharomyces paradoxus. Wine strains produced wine with fruity and floral characteristics, whereas wild strains produced wine with earthy and sulfurous characteristics. The differences that we observe between wine and wild strains provides further evidence that wine strains have evolved phenotypes that are distinct from their wild ancestors and relevant to their use in wine production. PMID:22093681

  3. Metabolic evolution of Escherichia coli strains that produce organic acids

    Science.gov (United States)

    Grabar, Tammy; Gong, Wei; Yocum, R Rogers

    2014-10-28

    This invention relates to the metabolic evolution of a microbial organism previously optimized for producing an organic acid in commercially significant quantities under fermentative conditions using a hexose sugar as sole source of carbon in a minimal mineral medium. As a result of this metabolic evolution, the microbial organism acquires the ability to use pentose sugars derived from cellulosic materials for its growth while retaining the original growth kinetics, the rate of organic acid production and the ability to use hexose sugars as a source of carbon. This invention also discloses the genetic change in the microorganism that confers the ability to use both the hexose and pentose sugars simultaneously in the production of commercially significant quantities of organic acids.

  4. Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

    Directory of Open Access Journals (Sweden)

    Nina Yusrina Muhamad Yunos

    2014-06-01

    Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

  5. Screening of mutant strains producing phytase from A. niger by 60Co γ-ray irradiation

    International Nuclear Information System (INIS)

    Yang Pingping; Wang Yan; Tao Wenyi

    2004-01-01

    60 Co γ-ray was used to irradiate Aspergillus niger 447-92 for screening the mutant strain of producing phytase, and the effects of mutation induction were determined and analyzed. A mutant strain A. niger 496-1 with high level of phytase was selected, the phytase properties of A. niger 496-1 were analyzed

  6. CHARACTERIZATION OF A NEW BACILLUS-STEAROTHERMOPHILUS ISOLATE - A HIGHLY THERMOSTABLE ALPHA-AMYLASE-PRODUCING STRAIN

    NARCIS (Netherlands)

    WIND, RD; BUITELAAR, RM; EGGINK, G; HUIZING, HJ; DIJKHUIZEN, L

    A novel strain of Bacillus stearothermophilus was isolated from samples of a potato-processing industry. Compared to known alpha-amylases from other B. stearothermophilus strains, the isolate was found to produce a highly thermostable alpha-amylase. The half-time of inactivation of this

  7. 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

  8. Detection and transmission of extracellular fac-tor producing Streptococcus suis serotype 2 strains in pigs

    NARCIS (Netherlands)

    Swildens, B.

    2009-01-01

    DETECTION AND TRANSMISSION OF EXTRACELLULAR FACTOR PRODUCING STREPTOCOCCUS SUIS SEROTYPE 2 STRAINS IN PIGS INTRODUCTION Streptococcus suis (S.suis) has been implicated in the etiology of many diseases among which meningitis in pigs. The virulent extracellular factor-positive strains of S.suis

  9. Morphological characterization of recombinant strains of Aspergillus oryzae producing alpha-amylase during batch cultivations

    DEFF Research Database (Denmark)

    Spohr, Anders Bendsen; Carlsen, Morten; Nielsen, Jens Bredal

    1997-01-01

    Three alpha-amylase producing strains of Aspergillus oryzae used for recombinant protein production have been studied with respect to growth and protein production. By comparing the three strains with respect to morphology and protein production it is shown that a morphological mutant with a more...

  10. Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

    Directory of Open Access Journals (Sweden)

    Abdelahhad Barbour

    Full Text Available BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS. A new medium for maximum biomass production buffered with 2-(N-morpholinoethanesulfonic acid (MES was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10 and salivaricin G32 (by strain YU10 from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. CONCLUSION: The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for

  11. Comparative Proteome Analysis between High Lipid-Producing Strain Mucor circinelloides WJ11 and Low Lipid-Producing Strain CBS 277.49.

    Science.gov (United States)

    Tang, Xin; Chen, Haiqin; Gu, Zhennan; Zhang, Hao; Chen, Yong Q; Song, Yuanda; Chen, Wei

    2017-06-21

    Mucor circinelloides is one of few oleaginous fungi that produces a useful oil rich in γ-linolenic acid, but it usually only produces <25% total lipid. Nevertheless, we isolated a new strain WJ11 that can produce up to 36% lipid of cell dry weight. In this study, we have systematically analyzed the global changes in protein levels between the high lipid-producing strain WJ11 and the low lipid-producing strain CBS 277.49 (15%, lipid/cell dry weight) at lipid accumulation phase through comparative proteome analysis. Proteome analysis demonstrated that the branched-chain amino acid and lysine metabolism, glycolytic pathway, and pentose phosphate pathway in WJ11 were up-regulated, while the activities of tricarboxylic acid cycle and branch point enzyme for synthesis of isoprenoids were retarded compared with CBS 277.49. The coordinated regulation at proteome level indicate that more acetyl-CoA and NADPH are provided for fatty acid biosynthesis in WJ11 compared with CBS 277.49.

  12. Metabolic engineering of a haploid strain derived from a triploid industrial yeast for producing cellulosic ethanol.

    Science.gov (United States)

    Kim, Soo Rin; Skerker, Jeffrey M; Kong, In Iok; Kim, Heejin; Maurer, Matthew J; Zhang, Guo-Chang; Peng, Dairong; Wei, Na; Arkin, Adam P; Jin, Yong-Su

    2017-03-01

    Many desired phenotypes for producing cellulosic biofuels are often observed in industrial Saccharomyces cerevisiae strains. However, many industrial yeast strains are polyploid and have low spore viability, making it difficult to use these strains for metabolic engineering applications. We selected the polyploid industrial strain S. cerevisiae ATCC 4124 exhibiting rapid glucose fermentation capability, high ethanol productivity, strong heat and inhibitor tolerance in order to construct an optimal yeast strain for producing cellulosic ethanol. Here, we focused on developing a general approach and high-throughput screening method to isolate stable haploid segregants derived from a polyploid parent, such as triploid ATCC 4124 with a poor spore viability. Specifically, we deleted the HO genes, performed random sporulation, and screened the resulting segregants based on growth rate, mating type, and ploidy. Only one stable haploid derivative (4124-S60) was isolated, while 14 other segregants with a stable mating type were aneuploid. The 4124-S60 strain inherited only a subset of desirable traits present in the parent strain, same as other aneuploids, suggesting that glucose fermentation and specific ethanol productivity are likely to be genetically complex traits and/or they might depend on ploidy. Nonetheless, the 4124-60 strain did inherit the ability to tolerate fermentation inhibitors. When additional genetic perturbations known to improve xylose fermentation were introduced into the 4124-60 strain, the resulting engineered strain (IIK1) was able to ferment a Miscanthus hydrolysate better than a previously engineered laboratory strain (SR8), built by making the same genetic changes. However, the IIK1 strain showed higher glycerol and xylitol yields than the SR8 strain. In order to decrease glycerol and xylitol production, an NADH-dependent acetate reduction pathway was introduced into the IIK1 strain. By consuming 2.4g/L of acetate, the resulting strain (IIK1A

  13. Draft Genome Sequence of Hoeflea sp. Strain BAL378, a Potential Producer of Bioactive Compounds

    DEFF Research Database (Denmark)

    Bentzon-Tilia, Mikkel; Riemann, Lasse; Gram, Lone

    2014-01-01

    Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer of bacterioc......Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer...

  14. Screening and Evaluation of Polyhydroxybutyrate-Producing Strains from Indigenous Isolate Cupriavidus taiwanensis Strains

    Directory of Open Access Journals (Sweden)

    Om-Murugan Janarthanan

    2011-01-01

    Full Text Available Polyhydroxyalkanoate (PHA is a biodegradable material with many potential biomedical applications, including medical implants and drug delivery. This study developed a system for screening production strains in order to optimize PHA production in Cupriavidus taiwanensis 184, 185, 186, 187, 204, 208, 209 and Pseudomona oleovorans ATCC 29347. In this study, Sudan black B staining, Infrared (IR and Gas Chromatography (GC analysis indicated that the best strain for PHA synthesis is C. taiwanensis 184, which obtains polyhydroxybutyrate (PHB. Cultivation of C. taiwanensis 184 under a pH of 7.0, at 30 °C, and at an agitation rate of 200 rpm, obtained a PHB content of 10% and PHB production of 0.14 g/L. The carbon and nitrogen types selected for analysis of PHB production by C. taiwanensis 184 were gluconic acid and NH4Cl, respectively. Optimal carbon/nitrogen ratio for PHB production was also determined. This study demonstrated a PHB content of 58.81% and a PHB production of 2.44 g/L when the carbon/nitrogen ratio of 8/1 was selected for C. taiwanensis 184. A two‑stage fermentation strategy significantly enhanced PHB content and PHB production. Under a two-stage fermentation strategy with nutrient‑limited conditions, C. taiwanensis 184 obtained a PHB content of 72% and a PHB concentration of 7 g/L. Finally, experimental results confirmed that optimizing the growth medium and fermentation conditions for cultivating the indigenous C. taiwanensis 184 strain substantially elevated PHB content from 10% to 72% and PHB production from 0.14 g/L to 7 g/L, respectively.

  15. Volatile compounds of Aspergillus strains with different abilities to produce ochratoxin A.

    Science.gov (United States)

    Jeleń, Henryk H; Grabarkiewicz-Szczesna, Jadwiga

    2005-03-09

    Volatile compounds emitted by Aspergillus strains having different abilities to produce ochratoxin A were investigated. Thirteen strains of Aspergillus ochraceus, three belonging to the A. ochraceus group, and eight other species of Aspergillus were examined for their abilities to produce volatile compounds and ochratoxin A on a wheat grain medium. The profiles of volatile compounds, analyzed using SPME, in all A. ochraceus strains, regardless of their toxeginicity, were similar and comprised mainly of 1-octen-3-ol, 3-octanone, 3-octanol, 3-methyl-1-butanol, 1-octene, and limonene. The prevailing compound was always 1-octen-3-ol. Mellein, which forms part of the ochratoxin A molecule, was found in both toxigenic and nontoxigenic strains. Volatile compounds produced by other Aspergillus strains were similar to those of A. ochraceus. Incubation temperatures (20, 24, and 27 degrees C) and water content in the medium (20, 30, and 40%) influenced both volatile compounds formation and ochratoxin A biosynthesis efficiency, although conditions providing the maximum amount of volatiles were different from those providing the maximum amount of ochratoxin A. The pattern of volatiles produced by toxigenic A. ochraceus strains does not facilitate their differentiation from nontoxigenic strains.

  16. Clostridium botulinum strains producing BoNT/F4 or BoNT/F5.

    Science.gov (United States)

    Raphael, Brian H; Bradshaw, Marite; Kalb, Suzanne R; Joseph, Lavin A; Lúquez, Carolina; Barr, John R; Johnson, Eric A; Maslanka, Susan E

    2014-05-01

    Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.

  17. [Morphological characteristics and physiological properties of aflatoxin B1 producing and non-producing Aspergillus flavus strains].

    Science.gov (United States)

    Kogbo, W; Lemarinier, S; Boutibonnes, P

    1985-09-01

    Comparison between about 80 strains of Aspergillus flavus, belonging to the series flavus and oryzae, obtained from international collections but also isolated from French or African substrates revealed the following observations: 1. Cultural and morphological characteristics of toxicogenic and atoxicogenic strains of A. flavus are similar. However, the former produce a diffusible yellow pigment in 83% of isolates. 2. The two groups of conidiospores have the same resistance to UV irradiation (254 nm, 5 and 10 min). All the strains are equally sensitive to 4 antifungal antibiotics: nystatine, ketoconazole, clotrimazole and amphotericine. 3. A difference was seen in the capacity to produce enzymes as alpha-galactosidase, beta-galactosidase and beta-glucosidase, implicated in the glucid metabolism. The specific hydrolytic activity has been confirmed by the characterization of a large amount of beta-galactosidase and by a diauxic growth on glucose medium supplemented by lactose. Possible relationship between these characters and aflatoxin B1 production by A. flavus strains is discussed.

  18. Strain diversity of CTX-M-producing Enterobacteriaceae in individual pigs

    DEFF Research Database (Denmark)

    Hansen, Katrine Hartung; Bortolaia, Valeria; Damborg, Peter Panduro

    2014-01-01

    of CTX-M-2/97-producing Proteus mirabilis or Providencia rettgeri was observed in two sows and two offspring. At least two genetically unrelated CTX-M-producing E. coli strains were isolated from approximately one fourth of the samples with remarkable differences between isolates obtained by enrichment...

  19. A rapid colorimetric screening method for vanillic acid and vanillin-producing bacterial strains.

    Science.gov (United States)

    Zamzuri, N A; Abd-Aziz, S; Rahim, R A; Phang, L Y; Alitheen, N B; Maeda, T

    2014-04-01

    To isolate a bacterial strain capable of biotransforming ferulic acid, a major component of lignin, into vanillin and vanillic acid by a rapid colorimetric screening method. For the production of vanillin, a natural aroma compound, we attempted to isolate a potential strain using a simple screening method based on pH change resulting from the degradation of ferulic acid. The strain Pseudomonas sp. AZ10 UPM exhibited a significant result because of colour changes observed on the assay plate on day 1 with a high intensity of yellow colour. The biotransformation of ferulic acid into vanillic acid by the AZ10 strain provided the yield (Yp/s ) and productivity (Pr ) of 1·08 mg mg(-1) and 53·1 mg L(-1) h(-1) , respectively. In fact, new investigations regarding lignin degradation revealed that the strain was not able to produce vanillin and vanillic acid directly from lignin; however, partially digested lignin by mixed enzymatic treatment allowed the strain to produce 30·7 mg l(-1) and 1·94 mg l(-1) of vanillic acid and biovanillin, respectively. (i) The rapid colorimetric screening method allowed the isolation of a biovanillin producer using ferulic acid as the sole carbon source. (ii) Enzymatic treatment partially digested lignin, which could then be utilized by the strain to produce biovanillin and vanillic acid. To the best of our knowledge, this is the first study reporting the use of a rapid colorimetric screening method for bacterial strains producing vanillin and vanillic acid from ferulic acid. © 2013 The Society for Applied Microbiology.

  20. [Isolation, identification and characterization of acid-producing strains from psychrotolerant biogas fermentation].

    Science.gov (United States)

    Wan, Yongqing; Zhang, Wei; Mandlaa; Tian, Ruihua; Wang, Ruigang; Duan, Kaihong

    2015-11-04

    The aim of this study was to screen acid-producing strains from the broth of psychrotolerant biogas fermentation and evaluate the acid-producing character of them. Acid-producing strains were isolated by a medium with methyl red at 4 degrees C in Petri dishes and identified by morphology observation and 16S rRNA sequencing. Moreover, the ability of hydrolysis of starch, fermentation of carbohydrates, liquefaction of gelatin and production of catalase were studied. Two acid-producing strains (FJ-8 and FJ-15) were isolated. The result of the 16S rRNA phylogenetic tree shows that FJ-8 and FJ-15 belong to Pseudomonas sp. and Shewanella sp., respectively. Both FJ-8 and FJ-15 could hydrolyze starch, liquidize gelatin and produce catalase. The optimum temperature for acid-producing of FJ-8 and FJ-15 is 15 degrees C and 20 degrees C, respectively. After 10 days cultivation at 4 degrees C, the concentration of acetic acid was 792 mg/L and 966 mg/L of FJ-8 and FJ-15, respectively. The selected strains, FJ-8 and FJ-15, have the potential to produce acids at low temperature.

  1. [GM1-dot-EIA for the detection of toxin-producing Vibrio cholerae strains].

    Science.gov (United States)

    Markina, O V; Alekseeva, L P; Telesmanich, N R; Chemisova, O S; Akulova, M V; Markin, N V

    2011-05-01

    A new variant of enzyme immunoassay (EIA) has been developed on the basis of GM1 gangliosides to detect the toxin-producing Vibrio cholerae strains--GM1-dot-EIA. Experiments were run using a nitrocellulose membrane to bind GM1 gangliosides and polyclonal antitoxic serum to detect cholerogen. GM1-dot-EIA testing identified cholera toxin in 11 of 13 supernatants of V. cholerae eltor ctx(+) strains isolated from man and in 3 of 7 supernatants of V. cholerae eltor ctx(+) strains isolated from water. These data agree with those obtained in CM1-EIA. There was no reaction with the supernatants of other microorganisms. The sensitivity of the technique was 10 ng/ml. Thus, the simple and specific GM1-dot-EIA may be recommended to detect toxin-producing V cholerae strains isolated from man and water.

  2. Isolation, Fermentation Optimization and Performance Studies of a Novel Biosurfactant Producing Strain Bacillus amyloliquefaciens

    OpenAIRE

    Zhang, W.; Zhang, X.; Cui, H.

    2015-01-01

    In this research, biosurfactant-producing bacteria were isolated from the outlet sludge of a canteen and one promising strain was identified through 16S rDNA sequence as Bacillus amyloliquefaciens. This strain can utilize water-soluble carbon source and the FT-IR analysis indicated the biosurfactant was probably glycolipids. Further factors (fermentation time, temperature, carbon source, nitrogen source, ion concentration) affecting the biosurfactant production were determined. The optimum fe...

  3. Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits.

    Science.gov (United States)

    Voon, W W Y; Rukayadi, Y; Meor Hussin, A S

    2016-05-01

    Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively. Biocellulose (BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. © 2016 The

  4. Technological and safety properties of newly isolated GABA-producing Lactobacillus futsaii strains.

    Science.gov (United States)

    Sanchart, C; Rattanaporn, O; Haltrich, D; Phukpattaranont, P; Maneerat, S

    2016-09-01

    To evaluate the technological and safety properties of Lactobacillus futsaii CS3 and CS5 isolated from Thai fermented shrimp products (Kung-Som) in order to develop a valuable gamma-aminobutyric acid (GABA)-producing starter culture. Both strains showed a high GABA-producing ability (>8 mg ml(-1) ) in MRS broth containing 20 mg ml(-1) monosodium glutamate (MSG) for 120 h. They also exhibited inhibitory activity against foodborne pathogens and spoilage bacteria. Cell surface hydrophobicity and proteolytic activity were observed in both strains. Strain CS3 survived better under simulated gastrointestinal tract conditions with only 1·5 log-units cell decrease over 8 h. Both strains showed the ability to deconjugate taurocholate and taurodeoxycholate acid. Neither virulence genes nor biogenic amine production was detected. Strain CS3 exhibited susceptibility to all tested antibiotics with the exception of vancomycin, while strain CS5 showed resistance to vancomycin, ampicillin and chloramphenicol. Based on the results obtained, Lact. futsaii CS3 is very promising as a GABA-producing and potentially probiotic starter culture strain for applications in functional fermented foods. This study focuses on the technological and safety characteristics of Lact. futsaii CS3 and CS5 including their high GABA-producing capacity for the first time. This provides a way of replacing chemical GABA by natural GABA using a GABA-producing starter culture candidate, at the same time offering the consumer new attractive food products. © 2016 The Society for Applied Microbiology.

  5. CHARACTERIZATION OF EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING ESCHERICHIA COLI STRAINS ISOLATED FROM DAIRY PRODUCTS

    Directory of Open Access Journals (Sweden)

    Rahem Khoshbakht

    2014-02-01

    Full Text Available Extended-spectrum β-lactamases (ESBLs are enzymes that hydrolyze the β-lactam ring, and ESBL-producing E. coli has rapidly spread worldwide with pose a serious hazard for humans. The aim of this study was to determine the prevalence of ESBL producing E. coli and molecular evaluation of four ESBL-associated genes among E. coli strains isolated from milk and cheese in southern Iran. Antibiotic susceptibility test was carried out for a total of 150 isolates of E. coli, previously collected from dairy products. ESBL production was screened using a double-disc synergy test (DDST and presence of four ESBL genes (PER, VEB, TEM and CTX-M was tested using PCR. Among 150 E. coli strains 57 (38% isolates were identified as ESBL-producing strains. All ESBL positive isolates could be typed for one or more genes and the most prevalent ESBL-associated gene was CTX-M (80.7%. The PER gene was not present among isolates. Isolates showed high susceptibility to imipe¬nem and cefoxitin. The results showed the high prevalence of ESBL producing E. coli strains among dairy products and high occurrence of CTX-M-associated ESBL activity among isolates indicating the hazards of increasing the strains with antibiotic resistance which can transfer to human trough the dairy food products.

  6. 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.

  7. In vitro evaluation of immunological properties of extracellular polysaccharides produced by Lactobacillus delbrueckii strains.

    Science.gov (United States)

    Kishimoto, Mana; Nomoto, Ryohei; Osawa, Ro

    2015-01-01

    We investigated the variation in immunological properties of the extracellular polysaccharides (EPSs) produced by different Lactobacillus delbrueckii strains as well as that of their monosaccharide composition. The monosaccharide composition of each EPS produced by L. delbrueckii strains, as determined by thin layer chromatography (TLC), showed an appreciable variation in a strain-dependent manner, which could be broadly assigned to 4 TLC groups. Meanwhile, the immunological properties of the EPSs produced by 10 L. delbrueckii strains were evaluated in a semi-intestinal model using a Transwell co-culture system, which employed human intestinal epithelial Caco-2 cells on the apical side and murine macrophage RAW264.7 cells on the basolateral side. Each EPS was added to the apical side to allow direct contact with Caco-2 cells and incubated for 6 hr. After incubation, the amounts of TNF-α and several cytokines that had been released by either RAW264.7 or Caco-2 cells were then quantified by cytotoxic activity on L929 cells or the RT-PCR method. It was found that the EPS-stimulated RAW264.7 cells express different profiles of cytokine production via Caco-2 cells but that the profile difference could not be related to the above TLC grouping. The evidence suggests that the EPSs of L. delbrueckii strains are diverse not only in their biochemical structure but also in their immunological properties.

  8. Recovery of succinic acid produced by fermentation of a metabolically engineered Mannheimia succiniciproducens strain.

    Science.gov (United States)

    Song, Hyohak; Huh, Yun Suk; Lee, Sang Yup; Hong, Won Hi; Hong, Yeon Ki

    2007-12-01

    There have recently been much advances in the production of succinic acid, an important four-carbon dicarboxylic acid for many industrial applications, by fermentation of several natural and engineered bacterial strains. Mannheimia succiniciproducens MBEL55E isolated from bovine rumen is able to produce succinic acid with high efficiency, but also produces acetic, formic and lactic acids just like other anaerobic succinic acid producers. We recently reported the development of an engineered M. succiniciproducens LPK7 strain which produces succinic acid as a major fermentation product while producing much reduced by-products. Having an improved succinic acid producer developed, it is equally important to develop a cost-effective downstream process for the recovery of succinic acid. In this paper, we report the development of a simpler and more efficient method for the recovery of succinic acid. For the recovery of succinic acid from the fermentation broth of LPK7 strain, a simple process composed of a single reactive extraction, vacuum distillation, and crystallization yielded highly purified succinic acid (greater than 99.5% purity, wt%) with a high yield of 67.05wt%. When the same recovery process or even multiple reactive extraction steps were applied to the fermentation broth of MBEL55E, lower purity and yield of succinic acid were obtained. These results suggest that succinic acid can be purified in a cost-effective manner by using the fermentation broth of engineered LPK7 strain, showing the importance of integrating the strain development, fermentation and downstream process for optimizing the whole processes for succinic acid production.

  9. NEW STRAINS PRODUCER OF BIOBUTANOL. ІІ. RENEWABLE LIGNOCELLULOSE FERMENTATION

    Directory of Open Access Journals (Sweden)

    Tigunova O. O.

    2014-08-01

    Full Text Available The purpose of our work was to study generic and specific affinity of domestic strainsproducers, comparative productivity butanol strains-producers screening, fermentation of sugars being a part of renewable lignocelluloses raw materials and to determine the conditions for the butanol yield increasing. The objects of research were strains Clostridium acetobutylicum ІМВ В-7407 (IFBG C6H, IFBG C4B and IFBG C7P from «Collection microorganism’s stains and plants line for food and agriculture biotechnology» of Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine. It was determined that domestic butanol-producing strains were relatively more productive and might be promising for improvement technology of butanol production.

  10. [Genetic modification of Methylobacterium extorquens G10 producer strain of polyhydroxybutyrate].

    Science.gov (United States)

    Fedorov, D N; Zamakhaeva, S A; Ezhov, V A; Doronina, N V; Trotsenko, Iu A

    2014-01-01

    The effect of the increased copy number of polyhydroxybutyrate (PHB) biosynthesis genes in pink-pigmented methylobacterium Methylobacterium extorquens G10 on properties of the biopolymer was studied. The activity of poly-3-hydroxybutyril-synthase (PHB-synthase) was shown to increase and the molecular weight of synthesized PHB decreases twofold (150 --> 79 kDa) after insertion of extra copies of phaC and phaCAB genes into cells of the producer strain, whereas the physicochemical properties of the plastic changed insignificantly. White mutant M. extorquens G10-W with disrupted synthesis of the carotenoid pigment (defect by the crtI gene, which codes for phytoene desaturase) was established to have the same rate of growth and level of PHB accumulation as the initial strain G10. The G10-W strain is a promising producer of PHB, with decreased expenses for purification and PHB biosynthesis.

  11. Characterisation of inhibitory substances produced by two Pseudoalteromonas species and the cyanobacterial strain Flo1

    OpenAIRE

    Rau, Jan Erik

    2011-01-01

    In the present study the inhibitory substances of P. aurantia NCIMB 2052T and P. citrea NCIMB 1889T were investigated with respect to their substantial and functional nature, their inhibitory potential, their stability against various treatments as well as the growth phases and incubation conditions when the substances are produced. In addition, an inhibitory substance produced by strain Flo1 was examined regarding its structure, function, and inhibitory potential. Furthermore, its taxonomic ...

  12. Design of homo-organic acid producing strains using multi-objective optimization

    DEFF Research Database (Denmark)

    Kim, Tae Yong; Park, Jong Myoung; Kim, Hyun Uk

    2015-01-01

    Production of homo-organic acids without byproducts is an important challenge in bioprocess engineering to minimize operation cost for separation processes. In this study, we used multi-objective optimization to design Escherichia coli strains with the goals of maximally producing target organic ...

  13. Genome Sequence of Lactococcus lactis subsp. lactis NCDO 2118, a GABA-Producing Strain

    DEFF Research Database (Denmark)

    Oliveira, Letícia C; Saraiva, Tessália D L; Soares, Siomar C

    2014-01-01

    Lactococcus lactis subsp. lactis NCDO 2118 is a nondairy lactic acid bacterium, a xylose fermenter, and a gamma-aminobutyric acid (GABA) producer isolated from frozen peas. Here, we report the complete genome sequence of L. lactis NCDO 2118, a strain with probiotic potential activity....

  14. Selected wild strains of Agaricus bisporus produce high yields of mushrooms at 25°C.

    Science.gov (United States)

    Navarro, Pilar; Savoie, Jean-Michel

    2015-01-01

    To cultivate the button mushroom Agaricus bisporus in warm countries or during summer in temperate countries, while saving energy, is a challenge that could be addressed by using the biological diversity of the species. The objective was to evaluate the yield potential of eight wild strains previously selected in small scale experiments for their ability to produce mature fruiting bodies at 25°C and above. Culture units of 8 kg of compost were used. The yield expressed as weight or number per surface unit and earliness of fruiting were recorded during cultivation in climatic rooms at 17, 25 or 30°C. Only strains of A. bisporus var. burnettii were able to fruit at 30°C. At 25°C they produced the highest yields (27 kg m(-2)) and had best earliness. The yields at 25°C for the strains of A. bisporus var. bisporus ranged from 12 to 16 kg m(-2). The yield ratios 25°C/17°C ranged from 0.8 to 1.2. The variety burnettii originated in the Sonoran Desert in California showed adaptation for quickly producing fruiting bodies at high temperature when humidity conditions were favorable. Strains of the variety bisporus showed interesting potentials for their ability to produce mature fruiting bodies at higher temperature than present cultivars and might be used in breeding programs. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  15. Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

    Directory of Open Access Journals (Sweden)

    Pradip Kumar Singh

    Full Text Available BACKGROUND: Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. METHODOLOGY/FINDINGS: The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. CONCLUSIONS: We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

  16. Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

    Science.gov (United States)

    Singh, Pradip Kumar; Chittpurna; Ashish; Sharma, Vikas; Patil, Prabhu B; Korpole, Suresh

    2012-01-01

    Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF) encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

  17. A New Bacillus licheniformis Mutant Strain Producing Serine Protease Efficient for Hvdrolvqis of Sov Meal Proteins.

    Science.gov (United States)

    Kostyleva, E V; Sereda, A S; Velikoretskaya, I A; Nefedova, L I; Sharikov, A Yu; Tsurikova, N V; Lobanov, N S; Semenova, M V; Sinitsyn, A P

    2016-07-01

    Induced mutagenesis with y-irradiation of the industrial strain Bacillus licheniformis-60 VKM B-2366,D was used to obtain a new highly active producer of an extracellular serine protease, Bacillus licheni- formis7 145. Samples of dry.concentrated preparations of serine protease produced by the original and mutant strains were obtained, and identity of their protein composition was'established. Alkaline serine protease sub- tilisin DY was the main component of the preparations. The biochemical and physicochemical properties of the Protolkheterm-145 enzyme preparation obtained from the mutant strain were studied. It exhibited pro- teolytic activity (1.5 times higher than the preparation from the initial strain) within broad ranges of pH (5- 11) and temperature (30-70'C).-Efficient hydrolysis of extruded soy meal protein at high concentrations (2 to 50%) in-the reaction mixture was.the main advantage of the Protolikheterm 145 preparation. Compared to,. the preparation obtained using the initial strain, the new preparation with increased proteolytic-activity pro- vided for more complete hydrolysis of the main non-nutritious soy,proteins.(glycinin and 0-conglycinin) with the yield of soluble protein increased by 19-28%, which decreased the cost of bioconversion of the protein- aceous material and indicated promise of the new preparation in resource-saving technologies for processing soy meals and cakes.

  18. [Antagonism against Beauveria bassiana by lipopeptide metabolites produced by entophyte Bacillus amyloliquefaciens strain SWB16].

    Science.gov (United States)

    Wang, Jingjie; Zhao, Dongyang; Liu, Yonggui; Ao, Xiang; Fan, Rui; Duan, Zhengqiao; Liu, Yanping; Chen, Qianqian; Jin, Zhixiong; Wan, Yongji

    2014-07-04

    We screened bacterial strains that have strong antagonism against Beauveria bassiana, an important pathogen of silkworm industry, and detected the antagonistic activity of lipopeptide metabolites. We identified bacterium SWB16 by morphological observation, physiological and biochemical experiments, 16SrRNA, and gyrA gene sequence analysis, tested antagonistic activity of strain SWB16 against Beauveria bassiana by measuring the inhibition zone diameter using filter paper diffusion method (Kirby-Bauer method), obtained lipopeptide metabolites of the strain using methanol extraction and observed the antagonism of strain SWB16 lipopeptide extracts against the conidia and hyphae of Beauveria bassiana, detected main ingredients and genes of lipopeptide metabolites by high-performance liquid chromatography-mass spectrometry and PCR amplification. SWB16 isolated from tissue of plant Dioscorea zingiberensis C. H. Wright belongs to Bacillus amyloliquefaciens and showed high antagonistic activity to Beauveria bassiana, and the lipopeptide extracts of isolate SWB16 exhibited significant inhibition to conidial germination and mycelial growth of Beauveria bassiana. The result of mass spectrometric detection indicated main component of the lipopeptide metabolites were fengcin and iturin, and genes fenB, ituA involved in the synthesis of them were amplified in the genome. Bacillus amyloliquefaciens strain SWB16 could produce lipopeptide antibiotics with strong antagonism to the entomopathogenic fungus Beauveria bassiana, and the results suggested that strain SWB16 has potential application value for controlling white muscardine of economic insects including silkworm.

  19. Detection and Characterization of Histamine-Producing Strains of Photobacterium damselae subsp. damselae Isolated from Mullets

    Directory of Open Access Journals (Sweden)

    Marcello Trevisani

    2017-06-01

    Full Text Available Photobacterium damselae subsp. damselae (Pdd is considered to be an emerging pathogen of marine fish and has also been implicated in cases of histamine food poisoning. In this study, eight strains isolated from mullets of the genera Mugil and Liza captured in the Ligurian Sea were characterized, and a method to detect histamine-producing Pdd from fish samples was developed. The histamine-producing potential of the strains was evaluated in culture media (TSB+ using a histamine biosensor. Subsequently, two strains were used to contaminate mackerel fillets (4 or 40 CFU/g, simulating a cross-contamination on the selling fish stalls. Sample homogenates were enriched in TSB+. The cultures were then inoculated on thiosulfate-citrate-bile salts-sucrose agar (TCBS and the dark green colonies were cultured on Niven agar. The violet isolates were characterized using specific biochemical and PCR based tests. All Pdd strains were histamine producers, yielding concentration varying from 167 and 8977 µg/mL in TSB+ cultures incubated at 30 °C for 24 h. Pdd colonies were detected from the inoculated mackerel samples and their histidine decarboxylase gene was amplified using species-specific primer pairs designed for this study. The results indicate that mullets can be source of Pdd and the fish retailers needs to evaluate the risk posed by cross-contamination on the selling fish stalls.

  20. Probiotic Properties of Exopolysaccharide-Producing Lactobacillus Strains Isolated from Tempoyak

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    Eilaf Suliman Khalil

    2018-02-01

    Full Text Available Tempoyak is a functional Malaysian food (an acid-fermented condiment which is produced from the pulp of the durian (Durio zibethinus fruit. The current study aimed to isolate and identify potential exopolysaccharide (EPS-producing Lactobacillus strains from tempoyak for potential use as probiotics. Seven isolates (DUR2, DUR4, DUR5, DUR8, DUR12, DUR18, and DUR20 out of 44 were able to produce EPS, and exhibited resistance to acid and bile salt compared to the reference strains Lactobacillus rhmnosus (ATCC53103 and L. plantarum (ATCC8014. The seven isolated strains belonged to five different species—L. plantarum, L. fermentum, L. crispatus, L. reuteri, and L. pentosus—which were identified using API 50 CHL and 16S rRNA gene sequences (Polymerase chain reaction, PCR – based. The seven strains displayed different ability to produce EPS (100–850 mg/L. Isolates exhibited a high survivability to acid (pH 3.0, bile salts (0.3%, and gastrointestinal tract model (<70%. Results showed that the auto-aggregation and cell surface hydrophobicity ranged from 39.98% to 60.09% and 50.80% to 80.53%, respectively, whereas, the highest co-aggregation value (66.44% was observed by L. fermentum (DUR8 with Pseudomonas aeruginosa. The isolates showed good inhibitory activity against tested pathogens, high antioxidant activity (32.29% to 73.36%, and good ability to reduce cholesterol (22.55% to 75.15%. Thus, the seven tested strains have value as probiotics.

  1. Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

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    Soares Márcia M.C.N.

    1999-01-01

    Full Text Available One hundred sixty eight bacterial strains, isolated from soil and samples of vegetable in decomposition, were screened for the use of citrus pectin as the sole carbon source. 102 were positive for pectinase depolymerization in assay plates as evidenced by clear hydrolization halos. Among them, 30% presented considerable pectinolytic activity. The cultivation of these strains by submerged and semi-solid fermentation for polygalacturonase production indicated that five strains of Bacillus sp produced high quantities of the enzyme. The physico-chemical characteristics, such as optimum pH of 6.0 - 7.0, optimum temperatures between 45oC and 55oC, stability at temperatures above 40oC and in neutral and alkaline pH, were determined.

  2. Physicochemical properties and membrane biofouling of extra-cellular polysaccharide produced by a Micrococcus luteus strain.

    Science.gov (United States)

    Feng, Lei; Li, Xiufen; Song, Ping; Du, Guocheng; Chen, Jian

    2014-07-01

    The physicochemical properties of the extra-cellular polysaccharide (EPS) produced by a Micrococcus luteus strain, a dominating strain isolated from membrane biofouling layer, were determined in this study. The EPS isolated from this strain was measured to have an average molecular weight of 63,540 Da and some typical polysaccharide absorption peaks in Fourier transform infrared spectrum. Monosaccharide components of the EPS contained rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose in a molar ratio of 0.2074:0.0454:0.0262:0.0446:1.7942:1.2086:0.4578. Pseudo plastic properties were also observed for the EPS through the rheological measurement. The EPS was further characterized for its behavior to cause membrane flux decline. The results showed that both flux declines for polyvinylidenefluoride (PVDF) and polypropylene membranes became more severe as EPS feed concentration increased. A higher irreversible fouling for the PVDF membrane suggested that the EPS had the larger fouling potential to this microfiltration membrane.

  3. The screening of bacillus subtilis strain with high-produced antimicrobial substance using N+ ion implantation

    International Nuclear Information System (INIS)

    Shen Juan; Bie Xiaomei; Lu Zhaoxin; Lu Fengxia; Zhu Xiaoyu

    2006-01-01

    N + ion implantation was used to obtain higher-yield antimicrobial substance. Bacillus subtilis fmbJ was mutated by 25 keV N + ion implantation with the dose of 50 x 2.6 x 10 13 , 80 x 2.6 x 10 13 , 100 x 2.6 x 10 13 , 120 x 2.6 x 10 13 and 150 x 2.6 x 10 13 N + /m 2 . Results showed that the optimal N + ion dose was 50 x 2.6 x 10 13 N + /m 2 , and a strain of high-yield antimicrobials was obtained and named as Bacillus subtilis fmbJ224. Its antimicrobial substance yield was increased by 96% than the initial. The fermentation characteristic of the strain was studied, and the mode of producing antimicrobial substance for the selected strain was arrearage synthesis type. (authors)

  4. Selection of bacteriocin producer strains of lactic acid bacteria from a dairy environment.

    Science.gov (United States)

    Lasagno, M; Beoleito, V; Sesma, F; Raya, R; Font de Valdez, G; Eraso, A

    2002-01-01

    Two strains showing bacteriocin production were selected from a total of 206 lactic acid bacteria isolated from samples of milk, milk serum, whey and homemade cheeses in Southern Cordoba, Argentina. This property was detected by means of well diffusion assays. The strains were identified as Enterococcus hirae and Enterococcus durans. The protein nature of those substances was proved by showing their sensitivity to type IV and XXV proteases, papaine, trypsin, pepsin and K proteinase. The bacteriocins inhibited the growth of Listeria monocytogenes, Bacillus cereus, Clostridium perfringes and two strains of Staphylococcus aureus, an A-enterotoxin and a B-enterotoxin producers. All of these bacteria are common pathogens usually associated with food borne diseases (ETA). These lactic acid bacteria or their bacteriocins could be suitable candidates for food preservation and specially useful in the our regional dairy industry.

  5. Characterization of new exopolysaccharides produced by coculturing of L. kefiranofaciens with yoghurt strains.

    Science.gov (United States)

    Ahmed, Zaheer; Wang, Yanping; Anjum, Nomana; Ahmad, Hajra; Ahmad, Asif; Raza, Mohsin

    2013-08-01

    This project was designed to study the coculturing affect of exopolysaccharide (EPS) producing strains Lactobacillus kefiranofaciens (L.k) ZW3, with non EPS producing strains L. bulgaricus (L.b) and Streptococcus thermophilus (S.t) in three different combinations: L.k+L.b, L.k+S.t, and L.k+L.b+S.t. FTIR analysis revealed presence of strong stretch in regions of 3400, 2900 and 1647cm(-1) which is characteristic of a typical polysaccharide. Co-cultured EPSs were composed of glucose, galactose, arabinose and xylose; and their sugar compositions were different from ZW3 polysaccharide that was mainly composed of gluco-galactan. Peak temperature for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers were 90.59, 87.61, 95.18 and 97.38°C, respectively. Thermal analysis revealed degradation temperature of 326.44, 294.6, 296.7 and 299.62°C for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers, respectively. SEM and AFM analysis divulged that three cocultured EPSs had different surface morphology than ZW3 polymer. Since co-cultured polymers have different structure than the polymer produced exclusively by EPS producing strain, it can be safely concluded from the study that co-culturing can be one way to change the structure of polymers. Coculturing of L. kefiranofaciens with non-EPS producing strains resulted in yoghurt with increased viscosity and delayed syneresis. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Effects of some organic pollutants on the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains

    International Nuclear Information System (INIS)

    Onbasli, Dilsad; Aslim, Belma

    2009-01-01

    In this study, isolation and characterization of exopolysaccharides produced by Pseudomonas aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants-polymer interactions, the yield and properties of their extracellular polysaccharide were researched. The exopolysaccharide production by these strains during growth in nutrient broth medium (control) was 41-75 mg L -1 . Also, P. aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 had exhibited high production of EPSs in presence of various organic pollutants (2,4-D, benzene, BTX and gasoline, respectively) in mineral salt medium (MSM) as a sole carbon source. EPS production by the 4 strains ranged from 40 mg L -1 to 8 mg L -1 . Monosaccharide composition of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol, ribose. The presence of galactronic acid, N-acetyl-D-galactosamin and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol was the basic structural unit of EPS produced by the strains except P. stutzeri B11 (MSM with 1% BTX). Strain B1 (in NB medium) was found to be composed of neutral sugars (100%) while strain B1 [in MSM medium with 0.2% (v/v) 2.4-D] contained neutral sugars (70.0%), acetylated amino sugars (30.0%). Also, EPS content of strain B5 (in the NB medium) was neutral sugars (99.8%), acetylated amino sugars (0.2%) while the strain B5 [in MSM medium containing the 1% (v/v) benzene] was found to contain neutral sugars (99.9%), acetylated amino sugars (0.1%). However, EPS monomer composition by strain B11 was detected as neutral sugars (99.77%), acetylated amino sugars (0.23%) in NB medium while the strain B11

  7. In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

    KAUST Repository

    Motwalli, Olaa Amin

    2017-01-05

    Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Results Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis. Conclusion To

  8. In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria.

    Science.gov (United States)

    Motwalli, Olaa; Essack, Magbubah; Jankovic, Boris R; Ji, Boyang; Liu, Xinyao; Ansari, Hifzur Rahman; Hoehndorf, Robert; Gao, Xin; Arold, Stefan T; Mineta, Katsuhiko; Archer, John A C; Gojobori, Takashi; Mijakovic, Ivan; Bajic, Vladimir B

    2017-01-05

    Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis. To our knowledge FFASC is the first

  9. Lignocellulose-Adapted Endo-Cellulase Producing Streptomyces Strains for Bioconversion of Cellulose-Based Materials.

    Science.gov (United States)

    Ventorino, Valeria; Ionata, Elena; Birolo, Leila; Montella, Salvatore; Marcolongo, Loredana; de Chiaro, Addolorata; Espresso, Francesco; Faraco, Vincenza; Pepe, Olimpia

    2016-01-01

    Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces ( S .) and in particular, the most highly represented species was Streptomyces argenteolus representing 50% of strains, while 8 strains were identified as Streptomyces flavogriseus (synonym S. flavovirens ) and Streptomyces fimicarius (synonyms Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies , and Streptomyces flavofuscus ), and the other four strains belonged to the species Streptomyces drozdowiczii, Streptomyces rubrogriseus, Streptomyces albolongus , and Streptomyces ambofaciens . Moreover, all Streptomyces strains, tested for endo and exo-cellulase, cellobiase, xylanase, pectinase, ligninase, peroxidase, and laccase activities using qualitative and semi-quantitative methods on solid growth medium, exhibited multiple enzymatic activities (from three to six). The 24 strains were further screened for endo-cellulase activity in liquid growth medium and the four best endo-cellulase producers ( S. argenteolus AE58P, S. argenteolus AE710A, S. argenteolus AE82P, and S. argenteolus AP51A) were subjected to partial characterization and their enzymatic crude extracts adopted to perform saccharification experiments on A. donax pretreated biomass. The degree of cellulose and xylan hydrolysis was evaluated by determining the kinetics of glucose and xylose release during 72 h incubation at 50°C from the pretreated biomass in the presence of cellulose degrading enzymes (cellulase and β-glucosidase) and xylan related activities (xylanase and β-xylosidase). The experiments were carried out utilizing the endo-cellulase activities from the selected S. argenteolus strains supplemented with commercial β-gucosidase and

  10. Characterization of high exopolysaccharide-producing Lactobacillus strains isolated from mustard pickles for potential probiotic applications.

    Science.gov (United States)

    Huang, Jing-Yao; Kao, Cheng-Yen; Liu, We-Sin; Fang, Tony J

    2017-06-01

    The aim of this study was to characterize high exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) isolated from mustard pickles in Taiwan for potential probiotic applications. Among 39 collected LAB strains, four most productive EPS-producing strains were selected for further analysis. Comparative analyses of 16S rDNA genes rpoA and pheS sequences demonstrated that these strains were members of Lactobacillus plantarum-group (LPG). NCD 2, NLD 4, SLC 13, and NLD 16 showed survival rates of 95.83% ± 0.49%, 95.07% ± 0.64%, 105.84% ± 0.82%, and 99.65% ± 0.31% under simulated gastrointestinal conditions, respectively. No cytotoxic effects on macrophage RAW 264.7 cells were observed when they were treated with a low dose (1 μg/ml) of stimulants extracted from the tested LAB strains. The production of nitric oxide in RAW 264.7 cells incubated with various LAB stimulants showed a dose-dependent increase. Among the four strains, SLC 13 showed higher inhibitory activity on growth of Enterococcus faecalis (BCRC 12302) and Yersinia enterocolitica (BCRC 10807). NLD 4 showed strong inhibitory activity against Escherichia coli O157:H7 (ATCC 43894) as compared with the other three strains. In summary, our results suggest that Lactobacillus pentosus SLC 13 may be a good candidate for probiotic applications and for development of antibacterial compounds. [Int Microbiol 20(2):75-84 (2017)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  11. Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels.

    Science.gov (United States)

    Guan, Xuefang; Xu, Qingxian; Zheng, Yi; Qian, Lei; Lin, Bin

    To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2h and in simulated intestinal fluid (pH 8.0) for 3h. The auto-aggregation rate increased to 87.74% after 24h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  12. Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels

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    Xuefang Guan

    Full Text Available ABSTRACT Objective To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. Methods The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. Results The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940 and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v in simulated gastric juice (pH 2.5 for 2 h and in simulated intestinal fluid (pH 8.0 for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. Conclusion These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

  13. Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

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    Arastoo Badoei-Dalfard

    2016-09-01

    Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

  14. Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

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    Susan R Leonard

    Full Text Available Consumption of fresh bagged spinach contaminated with Shiga toxin-producing Escherichia coli (STEC has led to severe illness and death; however current culture-based methods to detect foodborne STEC are time consuming. Since not all STEC strains are considered pathogenic to humans, it is crucial to incorporate virulence characterization of STEC in the detection method. In this study, we assess the comprehensiveness of utilizing a shotgun metagenomics approach for detection and strain-level identification by spiking spinach with a variety of genomically disparate STEC strains at a low contamination level of 0.1 CFU/g. Molecular serotyping, virulence gene characterization, microbial community analysis, and E. coli core gene single nucleotide polymorphism (SNP analysis were performed on metagenomic sequence data from enriched samples. It was determined from bacterial community analysis that E. coli, which was classified at the phylogroup level, was a major component of the population in most samples. However, in over half the samples, molecular serotyping revealed the presence of indigenous E. coli which also contributed to the percent abundance of E. coli. Despite the presence of additional E. coli strains, the serotype and virulence genes of the spiked STEC, including correct Shiga toxin subtype, were detected in 94% of the samples with a total number of reads per sample averaging 2.4 million. Variation in STEC abundance and/or detection was observed in replicate spiked samples, indicating an effect from the indigenous microbiota during enrichment. SNP analysis of the metagenomic data correctly placed the spiked STEC in a phylogeny of related strains in cases where the indigenous E. coli did not predominate in the enriched sample. Also, for these samples, our analysis demonstrates that strain-level phylogenetic resolution is possible using shotgun metagenomic data for determining the genomic relatedness of a contaminating STEC strain to other

  15. Isolation and screening of strains producing high amounts of rutin degrading enzymes from Fagopyrum tataricum seeds.

    Science.gov (United States)

    Zheng, Ya-Di; Luo, Qing-Lin; Zhou, Mei-Liang; Wang, De-Zhou; Zhang, Ye-Dong; Shao, Ji-Rong; Zhu, Xue-Mei; Tang, Yu

    2013-02-01

    The rutin degrading enzyme (RDE) was isolated and purified from tartary buckwheat seeds. The RDE was purified about 11.34-fold and its final yield was 3.5%, which was very low, due to our purification strategy of giving priority to purity over yield. The RDE molecular weight was estimated to be about 60 kDa. When rutin was used as substrate, an optimal enzyme activity was seen at around pH 5.0 and 40 °C. Strains isolation strategy characterized by the use of rutin as sole carbon source in enrichment cultures was used to isolate RDE-producing strains. Then the active strains were identified by morphology characterization and 18s rDNA-ITS (Internal Transcribed Spacer) gene sequencing. Three isolates coded as B3, W2, Y2 were successfully isolated from fusty Fagopyrum tataricum flour cultures. Strain B3 possessed the highest unit activity among these three strains, and its total activity reached up to 171.0 Unit. The active isolate (B3) could be assigned to Penicillium farinosum. When the Penicillium farinosum strains were added to tartary buckwheat flour cultures at pH 5.0, 30 °C after 5 days fermentation, the quercetin production raised up to 1.78 mg/l, almost 5.1 times higher than the fermentation without the above active strains. Hence, a new approach was available to utilize microorganism-aided fermentation for effective quercetin extraction from Fagopyrum tataricum seeds. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Genomic mutational analysis of the impact of the classical strain improvement program on ß–lactam producing Penicillium chrysogenum

    NARCIS (Netherlands)

    Salo, O.V.; Ries, M.; Medema, M.H.; Lankhorst, P.P.; Vreeken, R.J.; Bovenberg, R.A.L.; Driessen, A.J.M.

    2015-01-01

    Background Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of ß–lactams. The high ß–lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This involved

  17. Genomic mutational analysis of the impact of the classical strain improvement program on β-lactam producing Penicillium chrysogenum

    NARCIS (Netherlands)

    Salo, Oleksandr V; Ries, Marco; Medema, Marnix H; Lankhorst, Peter P; Vreeken, Rob J; Bovenberg, Roel A L; Driessen, Arnold J M

    2015-01-01

    BACKGROUND: Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of β-lactams. The high β-lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This

  18. Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

    Directory of Open Access Journals (Sweden)

    Xin Tang

    Full Text Available The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA; however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11 isolated in this laboratory can produce lipid up to 36% (w/w cell dry weight (CDW. We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

  19. Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

    Science.gov (United States)

    Tang, Xin; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

    2015-01-01

    The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA); however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11) isolated in this laboratory can produce lipid up to 36% (w/w) cell dry weight (CDW). We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w) lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL) to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

  20. Molecular Detection of Aflatoxin Producing Strains of Aspergillus Flavus from Peanut (Arachis Hypogaea

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    Adeela Hussain

    2015-02-01

    Full Text Available Aflatoxins are the potential carcinogens produced as secondary metabolites by Aspergillus flavus. They have the ability to contaminate large number of food which ultimately affect the human population. Malt extract agar was selected for the growth of control stains of fungus. The aim of the study was to develop a reliable and quick method for the detection of aflatoxin producing strains in peanuts by using molecular approaches. Total 80 samples of infected peanuts were collected from four different cities of Punjab and checked for their aflatoxin contamination. For aflatoxin detection, three target genes nor1, ver1 and aflR were selected which was involved in the aflatoxin biosynthesis. In all examined cases, 24 out of 80 (30% samples successfully amplified all three genes indicating aflatoxigenic activity. Discrimination between aflatoxigenic and non-aflatoxigenic strains were also determined on the basis of amplification of these three target DNA fragments. In this study, it was also demonstrated that only specific strains were able to produce the aflatoxin contamination in peanuts.

  1. CrdR function in a curdlan-producing Agrobacterium sp. ATCC31749 strain.

    Science.gov (United States)

    Yu, Xiaoqin; Zhang, Chao; Yang, Liping; Zhao, Lamei; Lin, Chun; Liu, Zhengjie; Mao, Zichao

    2015-02-10

    Agrobacterium sp. ATCC31749 is an efficient curdlan producer at low pH and under nitrogen starvation. The helix-turn-helix transcriptional regulatory protein (crdR) essential for curdlan production has been analyzed, but whether crdR directly acts to cause expression of the curdlan biosynthesis operon (crdASC) is uncertain. To elucidate the molecular function of crdR in curdlan biosynthesis, we constructed a crdR knockout mutant along with pBQcrdR and pBQNcrdR vectors with crdR expression driven by a T5 promoter and crdR native promoter, respectively. Also, we constructed a pAG with the green fluorescent protein (GFP) gene driven by a curdlan biosynthetic operon promoter (crdP) to measure the effects of crdR expression on curdlan biosynthesis. Compared with wild-type (WT) strain biomass production, the biomass of the crdR knockout mutant was not significantly different in either exponential or stationary phases of growth. Mutant cells were non-capsulated and planktonic and produced significantly less curdlan. WT cells were curdlan-capsulated and aggregated in the stationery phase. pBQcrdR transformed to the WT strain had a 38% greater curdlan yield and pBQcrdR and pBQNcrdR transformed to the crdR mutant strain recovered 18% and 105% curdlan titers of the WT ATCC31749 strain, respectively. Consistent with its function of promoting curdlan biosynthesis, curdlan biosynthetic operon promoter (crdP) controlled GFP expression caused the transgenic strain to have higher GFP relative fluorescence in the WT strain, and no color change was observed with low GFP relative fluorescence in the crdR mutant strain as evidenced by fluorescent microscopy and spectrometric assay. q-RT-PCR revealed that crdR expression in the stationary phase was greater than in the exponential phase, and crdR overexpression in the WT strain increased crdA, crdS, and crdC expression. We also confirmed that purified crdR protein can specifically bind to the crd operon promoter region, and we inferred

  2. Selection of daunorubicin-producing strain S. Coeruleorubidus by plasma radiation technology

    International Nuclear Information System (INIS)

    Jiang Shichun; Wu Jianping; Bai Hua

    2001-01-01

    The authors reported the results of mutagenesis by nitrogen plasma radiation with energy from 65 to 80 keV and dose from 9.6 x 10 9 to 1.5 x 10 11 /cm 2 in antineoplastic antibiotics daunorubicin-producing S. Coeruleorubidus. The relationship between death rate and radiation dose was formulated by computer and the formula. It was fit to a biological single-hit curve. The obtained high-producing mutagenic strain 137 was tested for its production property. The result showed that it could increase the daunorubicin potency by 25.8% in productive tanks of fermentation

  3. The hydrolytic enzymes produced by fungi strains isolated from the sand and soil of recreational areas

    Science.gov (United States)

    Kurnatowski, Piotr; Wójcik, Anna; Błaszkowska, Joanna; Góralska, Katarzyna

    2016-10-01

    The pathogenicity of fungi depends on, inter alia, the secretion of hydrolytic enzymes. The aim of this study was to determine the enzymatic activity of yeasts and yeast-like fungi isolated from children’s recreation areas, and compare the results with literature data of strains obtained from patients with mycoses. The enzymatic activity of 96 strains was assessed using an API ZYM kit (bioMerieux, France) and their biotypes were established. The fungal species were found to produce from 16 to 19 hydrolases: the most active were: leucine arylamidase (e5), acid phosphatase (e10), alkaline phosphatase (e1), naphthol-AS-BI-phosphohydrolase (e11), esterase – C4 (e2), β-galac - tosidase (e13) and β-glucosidase (e16). In addition, 13 biotypes characteristic of particular species of fungi were defined. Most strains could be categorized as biotypes C2 – 39.5% and A – 26%. The examined fungal strains isolated from recreational areas have selected biochemical characteristics i.e. production of hydrolases, which demonstrate their pathogenicity. They produce a number of enzymes which are also present in strains isolated from patients with mycoses, including: leucine arylamidase (e5), acid phosphatase (e10), naphthol-AS-BI-phosphohydrolase (e11) and alkaline phosphatase (e1). The biotypes identified in the course of this study (A, B3, B4, C1, C6 and D3) have been also reported in cases of fungal infection. Therefore, the fungi present in the sand and soil of recreational have pathogenic properties and are possible factors of fungal infection among children.

  4. Comparative Genomic and Phylogenetic Analysis of a Shiga Toxin Producing Shigella sonnei (STSS Strain

    Directory of Open Access Journals (Sweden)

    Domonkos Sváb

    2017-05-01

    Full Text Available Shigella strains are important agents of bacillary dysentery, and in recent years Shigella sonnei has emerged as the leading cause of shigellosis in industrialized and rapidly developing countries. More recently, several S. sonnei and Shigella flexneri strains producing Shiga toxin (Stx have been reported from sporadic cases and from an outbreak in America. In the present study we aimed to shed light on the evolution of a recently identified Shiga toxin producing S. sonnei (STSS isolated in Europe. Here we report the first completely assembled whole genome sequence of a multidrug resistant (MDR Stx-producing S. sonnei (STSS clinical strain and reveal its phylogenetic relations. STSS 75/02 proved to be resistant to ampicillin, streptomycin, tetracycline, chloramphenicol, thrimetoprim, and sulfomethoxazol. The genome of STSS 75/02 contains a 4,891,717 nt chromosome and seven plasmids including the 214 kb invasion plasmid (pInv harboring type III secretion system genes and associated effectors. The chromosome harbors 23 prophage regions including the Stx1 converting prophage. The genome carries all virulence determinants necessary for an enteroinvasive lifestyle, as well as the Stx1 encoding gene cluster within an earlier described inducible converting prophage. In silico SNP genotyping of the assembled genome as well as 438 complete or draft S. sonnei genomes downloaded from NCBI GenBank revealed that S. sonnei 75/02 belongs to the more recently diverged global MDR lineage (IIIc. Targeted screening of 1131 next-generation sequencing projects taken from NCBI Short Read Archive of confirms that only a few S. sonnei isolates are Stx positive. Our results suggest that the acquisition of Stx phages could have occurred in different environments as independent events and that multiple horizontal transfers are responsible for the appearance of Stx phages in S. sonnei strains.

  5. Lactobacillus plantarum CIDCA 8327: An α-glucan producing-strain isolated from kefir grains.

    Science.gov (United States)

    Gangoiti, M V; Puertas, A I; Hamet, M F; Peruzzo, P J; Llamas, M G; Medrano, M; Prieto, A; Dueñas, M T; Abraham, A G

    2017-08-15

    Lactobacillus plantarum CIDCA 8327 is an exopolysaccharide (EPS)-producer strain isolated from kefir with promising properties for the development of functional foods. The aim of the present study was to characterize the structure of the EPS synthesized by this strain grown in skim milk or semidefined medium (SDM). Additionally, genes involved in EPS synthesis were detected by PCR. L. plantarum produces an EPS with a molecular weight of 10 4 Da in both media. When grown in SDM produce an heteropolysaccharide composed mainly of glucose, glucosamine and rhamnose meanwhile the EPS produced in milk was composed exclusively of glucose indicating the influence of the sugar source. FTIR spectra of this EPS showed signals attributable to an α-glucan. Both by 1 H NMR and methylation analysis it was possible to determine that this polysaccharide is a branched α-(1→4)-d-glucan composed of 80% linear α-(1→4)-d-glucopyranosyl units and 19% (1→4)-d-glucopyranosyl units substituted at O-3 by single α-d-glucopyranosil residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Characterization of Partially Purified Bacteriocin Like Substance (BLIS Produced by Probiotic Lactobacillus Strains

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    Saeed Ismail Khanian

    2014-05-01

    Full Text Available Background: There is an increasing interest in search for antimicrobial peptides (bacteriocins and bacteriocin-like compounds produced by lactic acid bacteria (LAB because of their potential to be used as antimicrobial agents for improving the safety of food products. Objectives: The main objective of study was to evaluate the antibacterial potential of locally isolated Lactic Acid bacteria (LAB and determine their bacteriocin producing ability in in-vitro conditions. Materials and Methods: The antibacterial activity of 77 isolated LAB strains was tested against a number of pathogens by well-diffusion method. The isolates demonstrating antimicrobial potential were selected and tested for the production of bacteriocin or bacteriocin like substance. The bacteriocin produced by two of the isolates were partially purified and characterized. Results: The results indicated the neutralized supernatant fluid of two of the isolates identified as L. brevis LB32 and L. pentosus LP05, were active against the growth of Listeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus and Streptococcus pneumoniae. Additionally, L. brevis LB32 was able to inhibit the growth of Salmonella typhi and Klebsiella pneumoniae, while, S. pnuemoniae and L. monocytogenes appeared to be the most sensitive strain as apparent by highest zone of inhibition against these pathogens, respectively. The antimicrobial activity in the supernatant fluids of the mentioned strains remained unaffected after treating with enzymes catalase, lipase and lysozyme, while were strongly sensitive to the action of proteolytic enzymes, suggesting the presence of bacteriocin like inhibitory substance (BLIS in the two isolates. The inhibitory substance produced by the two isolates appeared heat resistant and tolerated 100˚C and 121˚C for 55 minutes and 20 minutes, respectively. Partial purification of the concentrated culture supernatant fluids of L. brevis LB32 and L

  7. Isolation and characterization of a biosurfactant producing strain, Brevibacilis brevis HOB1.

    Science.gov (United States)

    Haddad, Namir I A; Wang, Ji; Mu, Bozhong

    2008-12-01

    Biosurfactant-producing bacteria were isolated from the production water of an oil field. Isolates were screened for biosurfactant production using surface tension test. The highest reduction of surface tension was achieved with a bacterial strain which was identified by 16S rRNA gene sequencing as Brevibacilis brevis HOB1. It has been investigated using different carbon and nitrogen sources. It showed that the strain was able to grow and reduce the surface tension of the broth to 29 mN/m on commercial sugar and maltose, and to 32 mN/m on glucose after 72 h of growth. The maximum amount of biosurfactant was obtained when nitrate ions were supplied as nitrogen source. Biosurfactant produced by Brevibacilis brevis HOB1 was confirmed as a lipopeptide class of biosurfactant using TLC test and mass spectra. Lipopeptide isoforms were isolated from cell-free supernatants by acid-precipitation followed by one step of chromatographic separation on solid-phase ODS C18 column. The separation was confirmed by HPLC and ESI Q-TOF MS spectroscopy. Comparing the mass data obtained and the mass numbers reported for the lipopeptide complexes from other strains, it can be concluded that the major lipopeptide product of Brevibacilis brevis HOB1 is the surfactin isoform. This lipopeptide showed strong antibacterial and antifungal activity. It is a candidate for the biocontrol of pathogens in agriculture and other industries.

  8. Isolation and characterization of exopolysaccharide produced by Vibrio harveyi strain VB23.

    Science.gov (United States)

    Bramhachari, P V; Dubey, S K

    2006-11-01

    The aim of the study was to isolate and characterize exopolysaccharide (EPS) produced by Vibrio harveyi strain VB23. Growth and EPS production by V. harveyi strain VB23, was studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The rate of EPS production in batch cultures was highest during the late log phase of growth when compared with stationary growth phase. The exopolymer was recovered from the culture supernatant by using a cold ethanol precipitation-dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, proteins and sulfates. The purified EPS revealed prominent functional reactive groups, such as hydroxyl, carboxylic and amides, which correspond to a typical heteropolymeric polysaccharide and the EPS, also possessed good emulsification activity. The gas chromatographic analysis of an alditol acetate-derivatized sample of EPS revealed that it is composed primarily of galactose and glucose. Minor components found were rhamnose, fucose, ribose, arabinose, xylose and mannose. The EPS produced by V. harveyi strain VB23 is a heteropolysaccharide possessing good emulsification activity. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like EPS. This is the first report of EPS characterization in luminous V. harveyi bacteria, which describes the isolation and characterization of an EPS expressed by V. harveyi. The results of the study contributes significantly towards an understanding of the chemical composition and applications of the EPS in environmental biotechnology and bioremediation.

  9. Discovering potential Streptomyces hormone producers by using disruptants of essential biosynthetic genes as indicator strains.

    Science.gov (United States)

    Thao, Nguyen B; Kitani, Shigeru; Nitta, Hiroko; Tomioka, Toshiya; Nihira, Takuya

    2017-10-01

    Autoregulators are low-molecular-weight signaling compounds that control the production of many secondary metabolites in actinomycetes and have been referred to as 'Streptomyces hormones'. Here, potential producers of Streptomyces hormones were investigated in 40 Streptomyces and 11 endophytic actinomycetes. Production of γ-butyrolactone-type (IM-2, VB) and butenolide-type (avenolide) Streptomyces hormones was screened using Streptomyces lavendulae FRI-5 (ΔfarX), Streptomyces virginiae (ΔbarX) and Streptomyces avermitilis (Δaco), respectively. In these strains, essential biosynthetic genes for Streptomyces hormones were disrupted, enabling them to respond solely to the externally added hormones. The results showed that 20% of each of the investigated strains produced IM-2 and VB, confirming that γ-butyrolactone-type Streptomyces hormones are the most common in actinomycetes. Unlike the γ-butyrolactone type, butenolide-type Streptomyces hormones have been discovered in recent years, but their distribution has been unclear. Our finding that 24% of actinomycetes (12 of 51 strains) showed avenolide activity revealed for the first time that the butenolide-type Streptomyces hormone is also common in actinomycetes.

  10. Isolation of a yeast strain able to produce a polygalacturonase with maceration activity of cassava roots

    Directory of Open Access Journals (Sweden)

    María Alicia Martos

    2013-06-01

    Full Text Available The objective of the present study was the isolation of a yeast strain, from citrus fruit peels, able to produce a polygalacturonase by submerged fermentation with maceration activity of raw cassava roots. Among 160 yeast strains isolated from citrus peels, one strain exhibited the strongest pectinolytic activity. This yeast was identified as Wickerhamomyces anomalus by 5.8S-ITS RFLP analysis and confirmed by amplification of the nucleotide sequence. The yeast produced a polygalacturonase (PG in Erlenmeyer shake flasks containing YNB, glucose, and citrus pectin. PG synthesis occurred during exponential growth phase, reaching 51 UE.mL-1 after 8 hours of fermentation. A growth yield (Yx/s of 0.43 gram of cell dry weight per gram of glucose consumed was obtained, and a maximal specific growth rate (µm of 0.346 h-1 was calculated. The microorganism was unable to assimilate sucrose, galacturonic acid, polygalacturonic acid, or citrus pectin, but it required glucose as carbon and energy source and polygalacturonic acid or citrus pectin as inducers of enzyme synthesis. The crude enzymatic extract of Wickerhamomyces anomalus showed macerating activity of raw cassava. This property is very important in the production of dehydrated mashed cassava, a product of regional interest in the province of Misiones, Argentina.

  11. Characterization of volatile compounds produced by Lactobacillus helveticus strains in a hard cheese model.

    Science.gov (United States)

    Cuffia, Facundo; Bergamini, Carina V; Wolf, Irma V; Hynes, Erica R; Perotti, María C

    2018-01-01

    Starter cultures of Lactobacillus helveticus used in hard cooked cheeses play an important role in flavor development. In this work, we studied the capacity of three strains of L. helveticus, two autochthonous (Lh138 and Lh209) and one commercial (LhB02), to grow and to produce volatile compounds in a hard cheese extract. Bacterial counts, pH, profiles of organic acids, carbohydrates, and volatile compounds were analyzed during incubation of extracts for 14 days at 37 ℃. Lactobacilli populations were maintained at 10 6 CFU ml -1 for Lh138, while decreases of approx. 2 log orders were found for LhB02 and Lh209. Both Lh209 and LhB02 slightly increased the acetic acid content whereas mild increase in lactic acid was produced by Lh138. The patterns of volatiles were dependent on the strain which reflect their distinct enzymatic machineries: LhB02 and Lh209 produced a greater diversity of compounds, while Lh138 was the least producer strain. Extracts inoculated with LhB02 and Lh 209 were characterized by ketones, esters, alcohols, aldehydes, and acids, whereas in the extracts with Lh138 the main compounds belonged to aromatic, aldehydes, and ketones groups. Therefore, Lh209 and LhB02 could represent the best cheese starters to improve and intensify the flavor, and even a starter composed by combinations of LhB02 or Lh209 with Lh138 could also be a strategy to diversify cheese flavor.

  12. Annealing Behavior of Nanostructured Aluminum Produced by Cold Rolling to Ultrahigh Strains

    DEFF Research Database (Denmark)

    Cao, W.Q.; Godfrey, A.; Hansen, Niels

    2009-01-01

    The isochronal annealing behavior of nanostructured commercial purity aluminum (AA1100 and AA1200) produced by either cold rolling (CR) or accumulative roll bonding (ARB) up to ultrahigh strains of about 99.5 pct reduction in thickness has been studied in the temperature range from 200 degrees C...... to 420 degrees C. Microstructural and texture measurements were made using data from electron backscatter diffraction (EBSD) investigations, and the change in mechanical strength was followed using hardness measurements. A large effect of the rolling strain is observed on recovery at temperatures below...... for analyzing the uniformity of the structural coarsening, based on analysis of the crystallite size distribution with respect to the mode, is described. The analysis demonstrates that annealing leads to locally nonuniform changes in the microstructure, and to a description of the annealing process...

  13. KPC and VIM producing Enterobacter cloacae strain from a hospital in northeastern Venezuela.

    Science.gov (United States)

    Martínez, Dianny; Marcano, Daniel; Rodulfo, Hectorina; Salgado, Nurys; Cuaical, Nirvia; Rodriguez, Lucy; Caña, Luisa; Medina, Belkis; Guzman, Militza; De Donato, Marcos

    2015-06-01

    An 83-year-old male patient is admitted to the central hospital in Cumana, Venezuela with severe urinary infection, history of hospitalizaions and prolonged antimicrobial treatments. A strain of Enterobacter cloacae was isolated showing resistance to multiple types of antibiotics (only sensitive to gentamicin), with phenotype of serine- and metallo-carbapenemases. Both, bla(VIM-2) and bla(KPC) genes were detected in the isolate. This is the first report of an Enterobacteriaceae species producing both KPC carbapenemase and VIM metallo carbapenemase in Venezuela. This finding has a great clinical and epidemiological impact in the region, because of the feasibility of transferring these genes, through mobile elements to other strains of Enterobacter and to other infection-causing species of bacteria.

  14. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

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    Oggero Roberto

    2011-06-01

    Full Text Available Abstract Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Results Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76 log10 vs 3.90 (2.50-7.10 CFU/g of faeces (p = 0.015. The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp.delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method, also in liquid co-cultures, thus demonstrating an antagonistic activity. Conclusions This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms

  15. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants.

    Science.gov (United States)

    Savino, Francesco; Cordisco, Lisa; Tarasco, Valentina; Locatelli, Emanuela; Di Gioia, Diana; Oggero, Roberto; Matteuzzi, Diego

    2011-06-30

    Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log10 vs 3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp. delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity. This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky infants. Our findings may stimulate

  16. Proteome response of Tribolium castaneum larvae to Bacillus thuringiensis toxin producing strains.

    Directory of Open Access Journals (Sweden)

    Estefanía Contreras

    Full Text Available Susceptibility of Tribolium castaneum (Tc larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC(50 values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively. Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major categories; up-regulated proteins were involved in host defense (odorant binding protein C12, apolipophorin-III and chemosensory protein 18 and down-regulated proteins were linked to metabolic pathways affecting larval metabolism and development (pyruvate dehydrogenase Eα subunit, cuticular protein, ribosomal protein L13a and apolipoprotein LI-II. Among increased proteins, Odorant binding protein C12 showed the highest change, 4-fold increase in both toxin treatments. The protein displayed amino acid sequence and structural homology to Tenebrio molitor 12 kDa hemolymph protein b precursor, a non-olfactory odorant binding protein. Analysis of mRNA expression and mortality assays in Odorant binding protein C12 silenced larvae were consistent with a general immune defense function of non-olfactory odorant binding proteins. Regarding down-regulated proteins, at the transcriptional level, pyruvate dehydrogenase and cuticular genes were decreased in Tc larvae exposed to the Cry3Ba producing strain compared to the Cry23Aa/Cry37Aa producing strain, which may contribute to the developmental arrest that we observed with larvae fed the Cry3Ba producing strain. Results demonstrated a distinct host transcriptional regulation depending upon the Cry toxin treatment. Knowledge

  17. Isolation and identification of a thermophilic strain producing trehalose synthase from geothermal water in China.

    Science.gov (United States)

    Zhu, Yueming; Zhang, Jun; Wei, Dongsheng; Wang, Yufan; Chen, Xiaoyun; Xing, Laijun; Li, Mingchun

    2008-08-01

    A slightly thermophilic strain, CBS-01, producing trehalose synthase (TreS), was isolated from geothermal water in this study. According to the phenotypic characteristics and phylogenetic analysis of the 16s rRNA gene sequence, it was identified as Meiothermus ruber. The trehalose synthase gene of Meiothermus ruber CBS-01 was cloned by polymerase chain reaction and sequenced. The TreS gene consisted of 2,895 nucleotides, which specified a 964-amino-acid protein. This novel TreS catalyzed reversible interconversion of maltose and trehalose.

  18. Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

    Energy Technology Data Exchange (ETDEWEB)

    Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A. [Centre de Recherches sur les Macromolecules Vegetales, CNRS and Universite Joseph Fourier, B.P.53, F-38041 Grenoble (France); Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M. [Institut de Genetique et Microbiologie, Laboratoire de Genetique Moleculaire des Bacteries d' Interet Industriel, CNRS URA 2225, Batiment 360, Universite de Paris Sud, F-91405 Orsay (France)

    1998-12-31

    The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-{alpha}-d-Glcp-(1-2)-{beta}-d-Galf-(1-6)-{alpha}-d-Galp-(1-6) -{alpha}-d-Glcp-(1-3)-{beta}-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

    International Nuclear Information System (INIS)

    Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A.; Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M.

    1998-01-01

    The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-α-d-Glcp-(1-2)-β-d-Galf-(1-6)-α-d-Galp-(1-6) -α-d-Glcp-(1-3)-β-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. Removal Capacities of Polycyclic Aromatic Hydrocarbons (PAHs by a Newly Isolated Strain from Oilfield Produced Water

    Directory of Open Access Journals (Sweden)

    Yi-Bin Qi

    2017-02-01

    Full Text Available The polycyclic aromatic hydrocarbon (PAH-degrading strain Q8 was isolated from oilfield produced water. According to the analysis of a biochemical test, 16S rRNA gene, house-keeping genes and DNA–DNA hybridization, strain Q8 was assigned to a novel species of the genus Gordonia. The strain could not only grow in mineral salt medium (MM and utilize naphthalene and pyrene as its sole carbon source, but also degraded mixed naphthalene, phenanthrene, anthracene and pyrene. The degradation ratio of these four PAHs reached 100%, 95.4%, 73.8% and 53.4% respectively after being degraded by Q8 for seven days. A comparative experiment found that the PAHs degradation efficiency of Q8 is higher than that of Gordonia alkaliphila and Gordonia paraffinivorans, which have the capacities to remove PAHs. Fourier transform infrared spectra, saturate, aromatic, resin and asphaltene (SARA and gas chromatography–mass spectrometry (GC–MS analysis of crude oil degraded by Q8 were also studied. The results showed that Q8 could utilize n-alkanes and PAHs in crude oil. The relative proportions of the naphthalene series, phenanthrene series, thiophene series, fluorene series, chrysene series, C21-triaromatic steroid, pyrene, and benz(apyrene were reduced after being degraded by Q8. Gordonia sp. nov. Q8 had the capacity to remediate water and soil environments contaminated by PAHs or crude oil, and provided a feasible way for the bioremediation of PAHs and oil pollution.

  1. Pathway Construction in Corynebacterium glutamicum and Strain Engineering To Produce Rare Sugars from Glycerol.

    Science.gov (United States)

    Yang, Jiangang; Zhu, Yueming; Men, Yan; Sun, Shangshang; Zeng, Yan; Zhang, Ying; Sun, Yuanxia; Ma, Yanhe

    2016-12-21

    Rare sugars are valuable natural products widely used in pharmaceutical and food industries. In this study, we expected to synthesize rare ketoses from abundant glycerol using dihydroxyacetone phosphate (DHAP)-dependent aldolases. First, a new glycerol assimilation pathway was constructed to synthesize DHAP. The enzymes which convert glycerol to 3-hydroxypropionaldehyde and l-glyceraldehyde were selected, and their corresponding aldehyde synthesis pathways were constructed in vivo. Four aldol pathways based on different aldolases and phosphorylase were gathered. Next, three pathways were assembled and the resulting strains synthesized 5-deoxypsicose, 5-deoxysorbose, and 5-deoxyfructose from glucose and glycerol and produce l-fructose, l-tagatose, l-sorbose, and l-psicose with glycerol as the only carbon source. To achieve higher product titer and yield, the recombinant strains were further engineered and fermentation conditions were optimized. Fed-batch culture of engineered strains obtained 38.1 g/L 5-deoxypsicose with a yield of 0.91 ± 0.04 mol product per mol of glycerol and synthesized 20.8 g/L l-fructose, 10.3 g/L l-tagatose, 1.2 g/L l-sorbose, and 0.95 g/L l-psicose.

  2. Inhibition of food-related bacteria by antibacterial substances produced by Pseudomonas sp. strains isolated from pasteurized milk

    Directory of Open Access Journals (Sweden)

    Ana Beatriz Ferreira Rangel

    2013-12-01

    Full Text Available In this work, the production of antimicrobial substances by strains of Pseudomonas sp. isolated from pasteurized milk and their potential action against food-related bacteria were investigated. Samples of pasteurized milk were purchased from arbitrarily chosen commercial establishments in the city of Rio de Janeiro, Brazil. Of the four samples analyzed, three presented several typical colonies of Pseudomonas. About 100 colonies were chosen and subjected to biochemical tests for confirmation of their identity. Eighteen strains of the Pseudomonas genus were identified and submitted to tests for the production of antimicrobial substances. Twelve strains (66.7% were identified as Pseudomonas fluorescens, four (22.2% as P. aeruginosa, one (5.5% as P. mendocina and one (5.5% as P. pseudoalcaligenes. Only two P. fluorescens strains were unable to produce any antimicrobial substance against any of the indicator strains tested. Most of the strains presented a broad spectrum of action, inhibiting reference and food-related strains such as Proteus vulgaris, Proteus mirabilis, Hafnia alvei, Yersinia enterocolitica, Escherichia coli and Salmonella typhi. Five antimicrobial substance-producing strains, which presented the broadest spectrum of action, were also tested against Staphylococcus aureus reference strains and 26 Staphylococcus sp. strains isolated from foods, some of which were resistant to antibiotics. The producer strains 8.1 and 8.3, both P. aeruginosa, were able to inhibit all the staphylococcal strains tested. The antimicrobial substances produced by strains 8.1 and 8.3 did not seem to be typical bacteriocins, since they were resistant to the three proteolytic enzymes tested. Experiments involving the characterization of these substances are being carried out in order to evaluate their biotechnological application.

  3. Characterisation of the exopolysaccharide (EPS)-producing Lactobacillus paraplantarum BGCG11 and its non-EPS producing derivative strains as potential probiotics.

    Science.gov (United States)

    Nikolic, Milica; López, Patricia; Strahinic, Ivana; Suárez, Ana; Kojic, Milan; Fernández-García, María; Topisirovic, Ljubisa; Golic, Natasa; Ruas-Madiedo, Patricia

    2012-08-17

    Traditional fermented foods are the best source for the isolation of strains with specific traits to act as functional starters and to keep the biodiversity of the culture collections. Besides, these strains could be used in the formulation of foods claimed to promote health benefits, i.e. those containing probiotic microorganisms. For the rational selection of strains acting as probiotics, several in vitro tests have been proposed. In the current study, we have characterized the probiotic potential of the strain Lactobacillus paraplantarum BGCG11, isolated from a Serbian soft, white, homemade cheese, which is able to produce a "ropy" exopolysaccharide (EPS). Three novobiocin derivative strains, which have lost the ropy phenotype, were characterized as well in order to determine the putative role of the EPS in the probiotic potential. Under chemically gastrointestinal conditions, all strains were able to survive around 1-2% (10(6)-10(7)cfu/ml cultivable bacteria) only when they were included in a food matrix (1% skimmed milk). The strains were more resistant to acid conditions than to bile salts and gastric or pancreatic enzymes, which could be due to a pre-adaptation of the parental strain to acidic conditions in the cheese habitat. The ropy EPS did not improve the survival of the producing strain. On the contrary, the presence of an EPS layer surrounding the strain BGCG11 hindered its adhesion to the three epithelial intestinal cell lines tested, since the adhesion of the three non-ropy derivatives was higher than the parental one and also than that of the reference strain Lactobacillus rhamnosus GG. Aiming to propose a potential target application of these strains as probiotics, the cytokine production of peripheral blood mononuclear cells (PBMC) was analyzed. The EPS-producing L. paraplantarum BGCG11 strain showed an anti-inflammatory or immunosuppressor profile whereas the non-ropy derivative strains induced higher pro-inflammatory response. In addition, when

  4. Characterization of extracellular vitamin B12 producing Lactobacillus plantarum strains and assessment of the probiotic potentials.

    Science.gov (United States)

    Li, Ping; Gu, Qing; Yang, Lanlan; Yu, Yue; Wang, Yuejiao

    2017-11-01

    We investigated extracellular vitamin B 12 -producing Lactobacillus strains and their characteristics in tolerance to environmental stresses, gastric acid and bile salts. Two isolates, Lactobacillus plantarum LZ95 and CY2, showed high extracellular B 12 production, 98±15μg/L and 60±9μg/L respectively. Extracellular B 12 from LZ95 were identified as adenosylcobalamin and methylcobalamin using a combination of solid phase extraction and reverse-phase HPLC, while that from CY2 was adenosylcobalamin. Both strains grew under environmental stresses, and LZ95 exhibited better tolerance to low temperature and high ethanol concentration. LZ95 also showed good viability when exposed to gastric acid (pH 2.0 and 3.0) and bile salts (0.3%) as well as good adhesion to Caco-2 cells. The viability of CY2 was significantly reduced under low pH and exposure to bile salt. Together, extracellular B 12 producer LZ95 with good probiotic properties might be a candidate for in situ B 12 fortification in the food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Draft Genome Sequence of the Microbispora sp. Strain ATCC-PTA-5024, Producing the Lantibiotic NAI-107

    DEFF Research Database (Denmark)

    Sosio, M.; Gallo, G.; Pozzi, R.

    2014-01-01

    We report the draft genome sequence of Microbispora sp. strain ATCC-PTA-5024, a soil isolate that produces NAI-107, a new lantibiotic with the potential to treat life-threatening infections caused by multidrug-resistant Gram-positive pathogens. The draft genome of strain Microbispora sp. ATCC...

  6. Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea.

    Science.gov (United States)

    Dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

    2015-12-03

    Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. Copyright © 2015 dos Santos et al.

  7. Draft Genome Sequence of Komagataeibacter rhaeticus Strain AF1, a High Producer of Cellulose, Isolated from Kombucha Tea.

    Science.gov (United States)

    Dos Santos, Renato Augusto Corrêa; Berretta, Andresa A; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

    2014-07-24

    Here, we present the draft genome sequence of Komagatabaeicter rhaeticus strain AF1, which was isolated from Kombucha tea and is capable of producing high levels of cellulose. Copyright © 2014 dos Santos et al.

  8. Diversity of Micromonospora strains from the deep Mediterranean Sea and their potential to produce bioactive compounds

    Directory of Open Access Journals (Sweden)

    Andrea Gärtner

    2016-06-01

    Full Text Available During studies on bacteria from the Eastern Mediterranean deep-sea, incubation under in situ conditions (salinity, temperature and pressure and heat treatment were used to selectively enrich representatives of Micromonospora. From sediments of the Ierapetra Basin (4400 m depth and the Herodotos Plain (2800 m depth, 21 isolates were identified as members of the genus Micromonospora. According to phylogenetic analysis of 16S rRNA gene sequences, the Micromonospora isolates could be assigned to 14 different phylotypes with an exclusion limit of ≥ 99.5% sequence similarity. They formed 7 phylogenetic clusters. Two of these clusters, which contain isolates obtained after enrichment under pressure incubation and phylogenetically are distinct from representative reference organism, could represent bacteria specifically adapted to the conditions in situ and to life in these deep-sea sediments. The majority of the Micromonospora isolates (90% contained at least one gene cluster for biosynthesis of secondary metabolites for non-ribosomal polypeptides and polyketides (polyketide synthases type I and type II. The determination of biological activities of culture extracts revealed that almost half of the strains produced substances inhibitory to the growth of Gram-positive bacteria. Chemical analyses of culture extracts demonstrated the presence of different metabolite profiles also in closely related strains. Therefore, deep-sea Micromonospora isolates are considered to have a large potential for the production of new antibiotic compounds.

  9. Antiviral activity of the exopolysaccharide produced by Serratia sp. strain Gsm01 against Cucumber mosaic virus.

    Science.gov (United States)

    Ipper, Nagesh S; Cho, Saeyoull; Lee, Seon Hwa; Cho, Jun Mo; Hur, Jang Hyun; Lim, Chun Keun

    2008-01-01

    The potential of the exopolysaccharide (EPS) from a Serratia sp. strain Gsm01 as an antiviral agent against a yellow strain of Cucumber mosaic virus (CMV-Y) was evaluated in tobacco plants (Nicotiana tabacum cv. Xanthi-nc). The spray treatment of plants using an EPS preparation, 72 before CMV-Y inoculation, protected them against symptom appearance. Fifteen days after challenge inoculation with CMVY, 33.33% of plants showed mosaic symptoms in EPS-treated plants compared with 100% in the control plants. The EPS-treated plants, which showed mosaic symptoms, appeared three days later than the controls. The enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) analyses of the leaves of the protected plants revealed that the EPS treatment affected virus accumulation in those plants. Analysis of phenylalanine ammonia lyase, peroxidase, and phenols in protected plants revealed enhanced accumulation of these substances. The pathogenesis-related (PR) genes expression represented by PR-1b was increased in EPS-treated plants. This is the first report of a systemic induction of protection triggered by EPS produced by Serratia sp. against CMV-Y.

  10. Draft genome sequence of Paenibacillus algorifonticola sp. nov., an antimicrobial-producing strain

    Directory of Open Access Journals (Sweden)

    Liying Zhu

    2015-09-01

    Full Text Available Paenibacillus algorifonticola sp. nov. is isolated from a cold spring sample from Xinjiang Uyghur Autonomous Region (China, a novel strain that can produce antimicrobial substance against human pathogenic bacteria and fungi, including Staphylococcus aureus and Candida albicans. Here we report a 7.60-Mb assembly of its genome sequence and other useful information, including the coding sequences (CDSs responsible for the biosynthesis of antibacterial factors, anaerobic respiration and several immune-associated reactions. Also, prospective studies on P. algorifonticola sp. nov. in the cold spring might offer a potential source for the discovery of bioactive compounds with medical value. The data repository is deposited on the website http://www.ncbi.nlm.nih.gov/nuccore/LAQO00000000 and the accession number is LAQO00000000.

  11. Arabidopsis thaliana defense response to the ochratoxin A-producing strain (Aspergillus ochraceus 3.4412).

    Science.gov (United States)

    Hao, Junran; Wu, Weihong; Wang, Yan; Yang, Zhuojun; Liu, Yang; Lv, Yangjun; Zhai, Yanan; Yang, Jing; Liang, Zhihong; Huang, Kunlun; Xu, Wentao

    2015-05-01

    OTA-producing strain Aspergillus ochraceus induced necrotic lesions, ROS accumulation and defense responses in Arabidopsis . Primary metabolic and defense-related proteins changed in proteomics. Ascorbate-glutathione cycle and voltage-dependent anion-selective channel proteins fluctuated. Mycotoxigenic fungi, as widespread contaminants by synthesizing mycotoxins in pre-/post-harvest infected plants and even stored commercial cereals, could usually induce plant-fungi defense responses. Notably, ochratoxin A (OTA) is a nephrotoxic, hepatotoxic, teratogenic, immunotoxic and phytotoxic mycotoxin. Herein, defense responses of model system Arabidopsis thaliana detached leaves to infection of Aspergillus ochraceus 3.4412, an OTA high-producing strain, were studied from physiological, proteomic and transcriptional perspectives. During the first 72 h after inoculation (hai), the newly formed hypersensitive responses-like lesions, decreased chlorophyll content, accumulated reactive oxygen species and upregulated defense genes expressions indicated the defense response was induced in the leaves with the possible earlier motivated jasmonic acid/ethylene signaling pathways and the later salicylic acid-related pathway. Moreover, proteomics using two-dimensional gel electrophoresis 72 hai showed 16 spots with significantly changed abundance and 13 spots corresponding to 12 unique proteins were successfully identified by MALDI-TOF/TOF MS/MS. Of these, six proteins were involved in basic metabolism and four in defense-related processes, which included glutathione-S-transferase F7, voltage-dependent anion-selective channel protein 3 (VDAC-3), osmotin-like protein OSM34 and blue copper-binding protein. Verified from proteomic and/or transcriptional perspectives, it is concluded that the primary metabolic pathways were suppressed with the ascorbate-glutathione cycle fluctuated in response to A. ochraceus and the modulation of VDACs suggested the possibility of structural damage and

  12. Construction and evaluation of an exopolysaccharide-producing engineered bacterial strain by protoplast fusion for microbial enhanced oil recovery.

    Science.gov (United States)

    Sun, Shanshan; Luo, Yijing; Cao, Siyuan; Li, Wenhong; Zhang, Zhongzhi; Jiang, Lingxi; Dong, Hanping; Yu, Li; Wu, Wei-Min

    2013-09-01

    Enterobacter cloacae strain JD, which produces water-insoluble biopolymers at optimal temperature of 30°C, and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at high temperatures by protoplast fusion. The obtained fusant strain ZR3 produced exopolysaccharides at up to 45°C with optimal growth temperature at 35°C. The fusant produced exopolysaccharides of approximately 7.5 g/L or more at pH between 7.0 and 9.0. The feasibility of the enhancement of crude oil recovery with the fusant was tested in a sand-packed column at 40°C. The results demonstrated that bioaugmentation of the fusant was promising approach for MEOR. Mass growth of the fusant was confirmed in fermentor tests. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Genetic segregation in a high-yielding streptomycin-producing strain of Streptomyces griseus.

    Science.gov (United States)

    Roth, M; Schwalenberg, B; Reiche, R; Noack, D; Geuther, R; Eritt, I

    1982-01-01

    The streptomycin-producing Streptomyces griseus HP spontaneously segregated non-reverting derivatives with altered phenotypes. Clones characterized by increased spore formation and decreased streptomycin production were found. Two other types of derivatives were defective in aerial mycelium and streptomycin formation as well, but differed in the capacity to synthesize a yellow pigment. These derivatives were examined with respect to further properties. The stability of S. griseus HP was investigated in relation to conditions of continuous culture. Both at 26 and 30 degrees C, under glycerol and NH4Cl limitation a rapid segregation and enrichment of streptomycin-non-producing derivatives occurred. At 34 degrees C and glycerol limitation segregation began only after about 35 generations of continuous culture. In NH4Cl-limited chemostats the original strain was stable during 80 generations. In the course of the continuous culture experiments it was shown that the onset of genetic segregation within mycelia can be detected before it becomes obvious in colonies grown from the mycelia. This was achieved by fractionation of the mycelia by protoplast formation and subsequent plating on regeneration medium allowing colony growth and differentiation.

  14. Purification, biochemical characterization, and genetic cloning of the phytase produced by Burkholderia sp. strain a13.

    Science.gov (United States)

    Graminho, Eduardo Rezende; Takaya, Naoki; Nakamura, Akira; Hoshino, Takayuki

    2015-01-01

    A phytase-producing bacterium, Burkholderia sp. a13 (JCM 30421), was isolated from Lake Kasumigaura by enrichment cultivation using minimum medium containing phytic acid as the sole phosphorus source. The phytase production by strain a13 was induced by the presence of phytic acid and repressed by the addition of glucose. The purified enzyme had a molecular weight of 44 kDa and a phytase activity of 174 μmol min(-1) mg(-1). The enzyme showed broad substrate specificity, but the highest activity was observed with phytic acid. The enzyme activity was strongly inhibited by Cu(2+), Zn(2+), Hg(2+), and iodoacetic acid, indicating the requirement of a thiol group for the activity. Genetic cloning reveals that the mature portion of this enzyme consists of 428 amino acids with a calculated molecular weight of 46 kDa. The amino acid sequence showed the highest similarity to the phytase produced by Hafnia alvei with 48% identity; it also contained histidine acid phosphatase (HAP) motifs (RHGXRXP and HD), indicating the classification of this enzyme in the HAP phytase family. We have successfully expressed the cloned gene in Escherichia coli from its putative initiation codon, showing that the gene actually encodes the phytase.

  15. A hydrogen-producing, hydrogenase-free mutant strain of Nostoc punctiforme ATCC 29133

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, P.; Lindblad, P. [Uppsala Univ. (Sweden). Dept. of Physiological Botany; Schuetz, K.; Happe, T. [Universitaet Bonn (Germany). Botanisches Inst.

    2002-12-01

    The hupL gene, encoding the uptake hydrogenase large subunit, in Nostoc sp. strain ATCC 29133, a strain lacking a bidirectional hydrogenase, was inactivated by insertional mutagenesis. Recombinant strains were isolated and analysed, and one hupL{sup -} strain, NHM5, was selected for further study. Cultures of NHM5 were grown under nitrogen-fixing conditions and H{sub 2} evolution under air was observed using an H{sub 2} electrode. (Author)

  16. Genome Sequence of Lactobacillus saerimneri 30a (Formerly Lactobacillus sp. Strain 30a), a Reference Lactic Acid Bacterium Strain Producing Biogenic Amines

    NARCIS (Netherlands)

    Romano, Andrea; Trip, Hein; Campbell-Sills, Hugo; Bouchez, Olivier; Sherman, David; Lolkema, Juke S.; Lucas, Patrick M.

    2013-01-01

    Lactobacillus sp. strain 30a (Lactobacillus saerimneri) produces the biogenic amines histamine, putrescine, and cadaverine by decarboxylating their amino acid precursors. We report its draft genome sequence (1,634,278 bases, 42.6% G+C content) and the principal findings from its annotation, which

  17. Screening and identification of lactic acid bacteria strains with high acid-producing from traditional fermented yak yogurt

    Directory of Open Access Journals (Sweden)

    Chen Xiaoyong

    2017-01-01

    Full Text Available A total of 57 strains of lactic acid bacteria (LAB were isolated and purified from traditional fermented Yak Yogurt in Hongyuan-Sichuan and Yangbajing-Tibet. The strains with high acid-produced were screened by soluble calcium circle and titratable acidity determination. The five strains, 7-1, 22-1, 28-1, 34-1 and 62-1, possessed the high acid-producing and the value of titratable acidity is 196.2, 191.1, 192.2, 194.8 and 200.2 T respectively. Based on 16S rDNA sequence analysis, 22-1 was identified as Lactococcus lactis subsp. lactis, 28-1 as Lactobacillus casei, 34-1 as Lactobacillus fermentium, 7-1 and 62-1 as Enterococcus durans. This study could provide the evidence for researching fermentation strains to improve yogurt quality.

  18. Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome

    Science.gov (United States)

    Michelacci, Valeria; Bondì, Roslen; Gigliucci, Federica; Franz, Eelco; Badouei, Mahdi Askari; Schlager, Sabine; Minelli, Fabio; Tozzoli, Rosangela; Caprioli, Alfredo; Morabito, Stefano

    2016-01-01

    Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli. PMID:27584691

  19. The prevalence of ESBL-producing E-coli and Klebsiella strains in the Copenhagen area of Denmark

    DEFF Research Database (Denmark)

    Kjerulf, A.; Hansen, D.S.; Sandvang, D.

    2008-01-01

    The main purpose of the study was to investigate the frequency of ESBL-producing E. coli and Klebsiella strains in the Greater Copenhagen area. Four collections of strains were investigated: A) 380 consecutive E. coli and Klebsiella isolates primarily from urine, B) 200 gentamicin-resistant E. coli...... and Klebsiella isolates primarily from urine, C) 210 consecutive E. coli isolates from blood cultures, and D) 68 cefuroxime-resistant E. coli and Klebsiella isolates primarily from urine. Only one strain per patient was included. Strains with a zone diameter for cefpodoxime ...). In conclusion, the frequency of ESBL-producing E. coli and Klebsiella isolates was low in the Copenhagen area of Denmark (0.8 %). The most common ESBL genes found in our study were ctx-m and shv genes Udgivelsesdato: 2008/2...

  20. Structural identification of lipopeptide biosurfactants produced by Bacillus subtilis strains grown on the media obtained from renewable natural resources.

    Science.gov (United States)

    Paraszkiewicz, Katarzyna; Bernat, Przemysław; Kuśmierska, Anna; Chojniak, Joanna; Płaza, Grażyna

    2018-03-01

    The aim of the study was to identify and characterize lipopeptide (LP) biosurfactants produced by two Bacillus subtilis strains (KP7 and I'-1a) grown on various media prepared from renewable natural resources: two different brewery wastewaters (BW#4 and BW#6), 2% beet molasses (M), apple peels extract (APE) supplemented with 0.25% of yeast extract (YE) or 0.25% peptone (P), and similarly supplemented carrot peels extract (CPE). In all used media both strains retained their individual LP production signature characterized by surfactin and iturin overproduction exhibited by KP7 and I'-1a strain, respectively. The production level and the structural diversity of synthesized LPs were dependent on the medium composition. In the CPE+YE medium it was higher than the yield obtained in Luria-Bertani (140.6 and 100.3 mg L -1 , respectively). Surfactins were produced by both strains as a mixture of four homologues (C13-C16) with the domination of variant C14. All other broths prepared from renewable resources strongly stimulated the iturin production by I'-1a strain with the exception of BW media. The highest iturin concentration (428.7 mg L -1 ) obtained in the CPE+P culture of I'-1a strain was about seven-fold higher than in LB. In all cultures only iturin A was identified. Among four iturin homologues (C13-16) produced by I'-1a strain, the highest relative contents of C16 variant (70-80%) were calculated for samples obtained from APE+P and CPE+P media. The obtained data indicate that the waste composition has an influence on both the types and amounts of biosurfactants produced by studied B. subtilis strains. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Draft genome sequence of a thermostable, alkaliphilic α-amylase and protease producing Bacillus amyloliquefaciens strain KCP2.

    Science.gov (United States)

    Prajapati, Vimalkumar S; Ray, Sanket; Narayan, Jitendra; Joshi, Chaitanya C; Patel, Kamlesh C; Trivedi, Ujjval B; Patel, R M

    2017-12-01

    Bacillus amyloliquefaciens strain KCP2 was isolated from municipal food waste samples collected in Vallabh Vidyanagar, Gujarat, India. Strain KCP2 is noteworthy due to its ability to produce a thermostable, alkaliphilic α-amylase and a protease. These enzymes have importance in several industrial processes including bread making, brewing, starch processing, pharmacy, and textile industries. Whole genome sequencing of strain KCP2 showed that the estimated genome size was 3.9 Mb, the G + C content was 46%, and it coded for 4113 genes.

  2. Influence of gastrointestinal system conditions on adhesion of exopolysaccharide-producing Lactobacillus delbrueckii subsp. bulgaricus strains to caco-2 cells

    Directory of Open Access Journals (Sweden)

    Derya Onal Darilmaz

    2011-10-01

    Full Text Available This study aimed to assess the transit tolerance of potential probiotic dairy Lactobacillus strains in human uppergastrointestinal tract in vitro, and to evaluate the effect of EPS production on the viability and adhesion of these strains. Survival and adhesion of two exopolysaccharide (EPS-producing L. delbrueckii subsp. bulgaricus strains (B3 and B2 and E. coli ATCC11229 were assessed after the exposure of different pH (gastric juice and gastric plus pancreatic juice challenges. In the artificial gastric juice (pH 2, both the viability of the strain B3 and B2 was decreased. Artificial juice treatments significantly reduced the adhesion to caco-2 cells (P< 0.05. High EPS-producing B3 survived better in the adverse gastrointestinal conditions and showed better ability of adhesion to Caco-2 cells when assessed for competition with E. coli ATCC 11229 compared to low EPS-producing B2. This investigation showed that EPS production could be affected or be involved in the viability, adherence and competition of L. delbrueckii subsp. bulgaricus strains and support the potential of B3 strain for development of new probiotic products.

  3. Exopolysaccharide Produced by Probiotic Strain Lactobacillus paraplantarum BGCG11 Reduces Inflammatory Hyperalgesia in Rats

    Directory of Open Access Journals (Sweden)

    Miroslav Dinić

    2018-01-01

    Full Text Available The aim of this study was to test the potential of high molecular weight exopolysaccharide (EPS produced by the putative probiotic strain Lactobacillus paraplantarum BGCG11 (EPS CG11 to alleviate inflammatory pain in Wistar rats. The EPS CG11 was isolated from bacterial surface and was subjected to Fourier-transform infrared spectroscopy (FTIR and thermal analysis. FTIR spectra confirmed the polysaccharide structure of isolated sample, while the thermal methods revealed good thermal properties of the polymer. The antihyperalgesic and antiedematous effects of the EPS CG11 were examined in the rat model of inflammation induced by carrageenan injection in hind paw. The results showed that the intraperitoneal administration of EPS CG11 produced a significant decrease in pain sensations (mechanical hyperalgesia and a paw swelling in a dose-dependent manner as it was measured using Von Frey anesthesiometer and plethysmometer, respectively. These effects were followed by a decreased expression of IL-1β and iNOS mRNAs in rat’s paw tissue suggesting that the antihyperalgesic and antiedematous effects of the EPS CG11 are related to the suppression of inflammatory response. Additionally, we demonstrated that EPS CG11 exhibits immunosuppressive properties in the peritonitis model induced by carrageenan. Expression levels of pro-inflammatory mediators IL-1β, TNF-α and iNOS were decreased, together with the enhanced secretion of anti-inflammatory IL-10 and IL-6 cytokines, while neutrophil infiltration was not changed. To the best of our knowledge, this is the first study which reports an antihyperalgesic effect as the novel property of bacterial EPSs. Given the high demands of pharmaceutical industry for the replacement of commonly used analgesics due to numerous side effects, this study describes a promising natural compound for the future pharmacological testing in the area.

  4. Biosynthesis, purification and characterization of endoglucanase from a xylanase producing strain Aspergillus niger B03

    Directory of Open Access Journals (Sweden)

    Georgi Todorov Dobrev

    2012-03-01

    Full Text Available An extracellular endoglucanase was isolated from the culture liquid of xylanase producing strain Aspergillus niger B03. The enzyme was purified to a homogenous form, using consecutive ultrafiltration, anion exchange chromatography, and gel filtration. Endoglucanase was a monomer protein with a molecular weight of 26,900 Da determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 28,800 Da determined by gel filtration. The optimal pH and temperature values for the enzyme action were 3.5 and 65ºC respectively. Endoglucanase was stable at 40ºC, pH 3.0 for 210 min. The substrate specificity of the enzyme was determined with carboxymethyl cellulose, filter paper, and different glycosides. Endoglucanase displayed maximum activity in the case of carboxymethyl cellulose, with a Km value of 21.01 mg/mL. The substrate specificity and the pattern of substrate degradation suggested that the enzyme is an endoglucanase. Endoglucanase showed a synergism with endoxylanase in corn cobs hydrolysis.

  5. Screening of the White Button Mushroom (Agaricusbisporus Homokaryons and Producing New Hybrid Strain by SSR Markers

    Directory of Open Access Journals (Sweden)

    marzieh nourashrafeddin

    2018-02-01

    Full Text Available Introduction: Edible white button mushroom (Agaricusbisporus is the most common edible mushroom in Iran and the world. The yield of this mushroom is less than the average of yield in the world because of strain degeneration and using strains with low yield. Most of the current hybrids are either identical or very similar to the first hybrids. Ongoing breeding programs are exploiting the variability in Agaricus germplasm to produce new varieties with better traits including higher yield and resistance to biotic and abiotic stresses. One of the breeding programs is F1 production from parental homokaryons crossing. These homokaryonsis were isolated among germinated basidiospores on the culture media. During the last decades, various molecular markers based on nucleic acid polymorphisms (such as Restriction Fragment Length Polymorphism, Random Amplification of Polymorphic DNA, Amplified fragment of Length Polymorphism, Inter Simple Sequence Repeat, Simple Sequence Repeat markers have been used to differentiate homokaryons and heterokaryons. Microsatellites consist of short tandem repeat motifs distributed throughout the genome. Microsatellites are usually highly polymorphic due to a high degree of variation in the number of repeats among individuals. Microsatellite markers are multiallelic and co-dominant and thus tend to be more informative than other marker systems. Microsatellite markers have been widely developed in animals and plants and more recently in fungal species. The presence of microsatellites in the genome of A. bisporus was previously reported. Materials and Methods: In this research, 160 germinated basidiospores were collected from commercially cultivated strain A15 and they were grown on compost extract agar (CEA. The mycelial growth rate of these160 isolates was evaluated at 25°C on CEA medium. 18 isolates with slow growing rate were selected from 160 isolates. In the next step, co-dominant SSR markers were used to homokaryons

  6. A rapid enzymatic assay for high-throughput screening of adenosine-producing strains

    Science.gov (United States)

    Dong, Huina; Zu, Xin; Zheng, Ping; Zhang, Dawei

    2015-01-01

    Adenosine is a major local regulator of tissue function and industrially useful as precursor for the production of medicinal nucleoside substances. High-throughput screening of adenosine overproducers is important for industrial microorganism breeding. An enzymatic assay of adenosine was developed by combined adenosine deaminase (ADA) with indophenol method. The ADA catalyzes the cleavage of adenosine to inosine and NH3, the latter can be accurately determined by indophenol method. The assay system was optimized to deliver a good performance and could tolerate the addition of inorganic salts and many nutrition components to the assay mixtures. Adenosine could be accurately determined by this assay using 96-well microplates. Spike and recovery tests showed that this assay can accurately and reproducibly determine increases in adenosine in fermentation broth without any pretreatment to remove proteins and potentially interfering low-molecular-weight molecules. This assay was also applied to high-throughput screening for high adenosine-producing strains. The high selectivity and accuracy of the ADA assay provides rapid and high-throughput analysis of adenosine in large numbers of samples. PMID:25580842

  7. A new nitrilase-producing strain named Rhodobacter sphaeroides LHS-305: biocatalytic characterization and substrate specificity.

    Science.gov (United States)

    Yang, Chunsheng; Wang, Xuedong; Wei, Dongzhi

    2011-12-01

    The characteristics of the new nitrilase-producing strain Rhodobacter sphaeroides LHS-305 were investigated. By investigating several parameters influencing nitrilase production, the specific cell activity was ultimately increased from 24.5 to 75.0 μmol g(-1) min(-1), and hereinto, the choice of inducer proved the most important factor. The aromatic nitriles (such as 3-cyanopyridine and benzonitrile) were found to be the most favorable substrates of the nitrilase by analyzing the substrate spectrum. It was speculated that the unsaturated carbon atom attached to the cyano group was crucial for this type of nitrilase. The value of apparent K (m), substrate inhibition constant, and product inhibition constant of the nitrilase against 3-cyanopyridine were 4.5 × 10(-2), 29.2, and 8.6 × 10(-3) mol L(-1), respectively. When applied in nicotinic acid preparation, the nitrilase is able to hydrolyze 200 mmol L(-1) 3-cyanopyridine with 93% conversion rate in 13 h by 6.1 g L(-1) cells (dry cell weight).

  8. THE KINETICS OF THE REACTIONS CATALYZED BY AN ENZYMATIC PREPARATION PRODUCED BY A BACILLUS LICHENIFORMIS STRAIN

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    MONICA DRAGOMIRESCU

    2007-05-01

    Full Text Available Robust immobilization techniques that preserve the activity of biomolecules have manypotential applications. In recent years, a number of new bioimobilisation methods in solgel-derived materials were reported. The interactions between the biomolecule and theinorganic material determine the degree to which the biomolecule retains its nativeproperties. The newer technological developments in the field of immobilizedbiocatalysts can offer the possibility of a wider and more economical exploitation ofbiocatalysts in biological applications, food and feed industry, medicine, and in thedevelopment of bioprocess monitoring devices, like the biosensors.The aim of this study was to obtain immobilized enzymatic preparations by methodswhich affect enzyme conformations and kinetic parameters as less as possible. Weimmobilized the enzymatic preparation with protease activity produced by a Bacilluslicheniformis B 40 local strain by physical bonding on ceramics and entrapment into solgel-derived glasses obtained from tetraethyl orthosilicate (TEOS, deposited in thin layeron a ceramic support (entrapment/deposition. Both physically adsorbed andentrapped/deposited enzymes follow Michaelis-Menten kinetics, similar with the solubleenzyme. In the case of immobilized enzymes, the apparent Michaelis constant, Km, wasgreater than that of the native one, as it was expected. The kinetic parameters indicatethat the enzymatic preparations adsorbed on ceramic support and entrapped/depositedshow less affinity for the substrate, Km being 1.3 and 2.1 times higher than that of thenative enzyme, respectively. The maximum velocity increased also by 3.5 and 7.9 timesrespectively, compared with the free counterpart (according to Lineweaver-Burklinearization.

  9. Integrative Gene Cloning and Expression System for Streptomyces sp. US 24 and Streptomyces sp. TN 58 Bioactive Molecule Producing Strains

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    Samiha Sioud

    2009-01-01

    Full Text Available Streptomyces sp. US 24 and Streptomyces sp. TN 58, two strains producing interesting bioactive molecules, were successfully transformed using E. coli ET12567 (pUZ8002, as a conjugal donor, carrying the integrative plasmid pSET152. For the Streptomyces sp. US 24 strain, two copies of this plasmid were tandemly integrated in the chromosome, whereas for Streptomyces sp. TN 58, the integration was in single copy at the attB site. Plasmid pSET152 was inherited every time for all analysed Streptomyces sp. US 24 and Streptomyces sp. TN 58 exconjugants under nonselective conditions. The growth, morphological differentiation, and active molecules production of all studied pSET152 integrated exconjugants were identical to those of wild type strains. Consequently, conjugal transfer using pSET152 integration system is a suitable means of genes transfer and expression for both studied strains. To validate the above gene transfer system, the glucose isomerase gene (xylA from Streptomyces sp. SK was expressed in strain Streptomyces sp. TN 58. Obtained results indicated that heterologous glucose isomerase could be expressed and folded effectively. Glucose isomerase activity of the constructed TN 58 recombinant strain is of about eighteenfold higher than that of the Streptomyces sp. SK strain. Such results are certainly of importance due to the potential use of improved strains in biotechnological process for the production of high-fructose syrup from starch.

  10. A new stoichiometric miniaturization strategy for screening of industrial microbial strains: application to cellulase hyper-producing Trichoderma reesei strains

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    Jourdier Etienne

    2012-05-01

    Full Text Available Abstract Background During bioprocess development, secondary screening is a key step at the boundary between laboratory and industrial conditions. To ensure an effective high-throughput screening, miniaturized laboratory conditions must mimic industrial conditions, especially for oxygen transfer, feeding capacity and pH stabilization. Results A feeding strategy has been applied to develop a simple screening procedure, in which a stoichiometric study is combined with a standard miniaturization procedure. Actually, the knowledge of all nutriments and base or acid requirements leads to a great simplification of pH stabilization issue of miniaturized fed-batch cultures. Applied to cellulase production by Trichoderma reesei, this strategy resulted in a stoichiometric mixed feed of carbon and nitrogen sources. While keeping the pH between shake flask and stirred bioreactor comparable, the developed shake flask protocol reproduced the strain behaviour under stirred bioreactor conditions. Compared to a an already existing miniaturized shake flasks protocol, the cellulase concentration was increased 5-fold, reaching about 10 g L-1. Applied to the secondary screening of several clones, the newly developed protocol succeeded in selecting a clone with a high industrial potential. Conclusions The understanding of a bioprocess stoichiometry contributed to define a simpler and more effective miniaturization. The suggested strategy can potentially be applied to other fed-batch processes, for the screening of either strain collections or experimental conditions.

  11. Study on breeding of daptomycin-producing strains by nitrogen ion implantation

    International Nuclear Information System (INIS)

    Zhou Jian; Liu Ying; Fang Dongsheng; Jiang Hong; Zhang Yin; Gao Wuyan

    2008-01-01

    Streptomyces roseosporus C20, the bacteria used in production of daptomycin, were implanted with (15-200)x10 13 /cm 2 of 20keV N + ions. Survival rate of the bacteria at different absorbed doses was investigated, and mutagenic effects of the microbe were studied. After breeding under the selection pressure of resistance to streptomycin (the lethal concentration is 1.2μg/mL), several mutant strains with higher yields of daptomycin have been obtained. One of mutant strains, N3-36, can increase up to 126% compared to the original strain. It also shows that the mutant strains have high genetic stability. (authors)

  12. Characterization of a novel biosurfactant produced by Staphylococcus sp. strain 1E with potential application on hydrocarbon bioremediation.

    Science.gov (United States)

    Eddouaouda, Kamel; Mnif, Sami; Badis, Abdelmalek; Younes, Sonia Ben; Cherif, Slim; Ferhat, Samira; Mhiri, Najla; Chamkha, Mohamed; Sayadi, Sami

    2012-08-01

    A biosurfactant-producing bacterium (Staphylococcus sp. strain 1E) was isolated from an Algerian crude oil contaminated soil. Biosurfactant production was tested with different carbon sources using the surface tension measurement and the oil displacement test. Olive oil produced the highest reduction in surface tension (25.9 dynes cm(-1)). Crude oil presented the best substrate for 1E biosurfactant emulsification activity. The biosurfactant produced by strain 1E reduced the growth medium surface tension below 30 dynes cm(-1). This reduction was also obtained in cell-free filtrates. Biosurfactant produced by strain 1E showed stability in a wide range of pH (from 2 to 12), temperature (from 4 to 55 °C) and salinity (from 0 to 300 g l(-1)) variations. The biosurfactant produced by strain 1E belonged to lipopeptide group and also constituted an antibacterial activity againt the pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Phenanthrene solubility in water was enhanced by biosurfactant addition. Our results suggest that the 1E biosurfactant has interesting properties for its application in bioremediation of hydrocarbons contaminated sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Clonality and Resistome analysis of KPC-producing Klebsiella pneumoniae strain isolated in Korea using whole genome sequencing.

    Science.gov (United States)

    Lee, Yangsoon; Kim, Bong-Soo; Chun, Jongsik; Yong, Ji Hyun; Lee, Yeong Seon; Yoo, Jung Sik; Yong, Dongeun; Hong, Seong Geun; D'Souza, Roshan; Thomson, Kenneth S; Lee, Kyungwon; Chong, Yunsop

    2014-01-01

    We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC-) producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR) K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including bla KPC-2, bla SHV-11, bla TEM-169, and bla OXA-9. MP14 also possessed aac(6'-)Ib, aadA2, and aph(3'-)Ia as aminoglycoside resistance-encoding genes, mph(A) for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains) isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

  14. Clonality and Resistome Analysis of KPC-Producing Klebsiella pneumoniae Strain Isolated in Korea Using Whole Genome Sequencing

    Directory of Open Access Journals (Sweden)

    Yangsoon Lee

    2014-01-01

    Full Text Available We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC- producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including blaKPC-2, blaSHV-11, blaTEM-169, and blaOXA-9. MP14 also possessed aac(6′-Ib, aadA2, and aph(3′-Ia as aminoglycoside resistance-encoding genes, mph(A for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

  15. Draft Whole-Genome Sequence of Bacillus altitudinis Strain B-388, a Producer of Extracellular RNase.

    Science.gov (United States)

    Shah Mahmud, Raihan; Ulyanova, Vera; Malanin, Sergey; Dudkina, Elena; Vershinina, Valentina; Ilinskaya, Olga

    2015-01-29

    Here, we present a draft genome sequence of Bacillus altitudinis strain B-388, including a putative plasmid. The strain was isolated from the intestine of Indian meal moth, a common pest of stored grains, and it is characterized by the production of extracellular RNase, similar to binase, which is of interest for comparative studies and biotechnology. Copyright © 2015 Shah Mahmud et al.

  16. How Posttranslational Modification of Nitrogenase Is Circumvented in Rhodopseudomonas palustris Strains That Produce Hydrogen Gas Constitutively

    Science.gov (United States)

    Heiniger, Erin K.; Oda, Yasuhiro; Samanta, Sudip K.

    2012-01-01

    Nitrogenase catalyzes the conversion of dinitrogen gas (N2) and protons to ammonia and hydrogen gas (H2). This is a catalytically difficult reaction that requires large amounts of ATP and reducing power. Thus, nitrogenase is not normally expressed or active in bacteria grown with a readily utilized nitrogen source like ammonium. nifA* mutants of the purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris have been described that express nitrogenase genes constitutively and produce H2 when grown with ammonium as a nitrogen source. This raised the regulatory paradox of why these mutants are apparently resistant to a known posttranslational modification system that should switch off the activity of nitrogenase. Microarray, mutation analysis, and gene expression studies showed that posttranslational regulation of nitrogenase activity in R. palustris depends on two proteins: DraT2, an ADP-ribosyltransferase, and GlnK2, an NtrC-regulated PII protein. GlnK2 was not well expressed in ammonium-grown NifA* cells and thus not available to activate the DraT2 nitrogenase modification enzyme. In addition, the NifA* strain had elevated nitrogenase activity due to overexpression of the nif genes, and this increased amount of expression overwhelmed a basal level of activity of DraT2 in ammonium-grown cells. Thus, insufficient levels of both GlnK2 and DraT2 allow H2 production by an nifA* mutant grown with ammonium. Inactivation of the nitrogenase posttranslational modification system by mutation of draT2 resulted in increased H2 production by ammonium-grown NifA* cells. PMID:22179236

  17. Comparison of methods for glycogen analysis of in vitro fermentation pellets produced with strained ruminal inoculum.

    Science.gov (United States)

    Hall, Mary Beth; Hatfield, Ronald D

    2015-11-01

    Microbial glycogen measurement is used to account for fates of carbohydrate substrates. It is commonly applied to washed cells or pure cultures which can be accurately subsampled, allowing the use of smaller sample sizes. However, the nonhomogeneous fermentation pellets produced with strained rumen inoculum cannot be accurately subsampled, requiring analysis of the entire pellet. In this study, two microbial glycogen methods were compared for analysis of such fermentation pellets: boiling samples for 3h in 30% KOH (KOH) or for 15min in 0.2M NaOH (NaOH), followed by enzymatic hydrolysis with α-amylase and amyloglucosidase, and detection of released glucose. Total α-glucan was calculated as glucose×0.9. KOH and NaOH did not differ in the α-glucan detected in fermentation pellets (29.9 and 29.6mg, respectively; P=0.61). Recovery of different control α-glucans was also tested using KOH, NaOH, and a method employing 45min of bead beating (BB). For purified beef liver glycogen (water-soluble) recovery, BB (95.0%)>KOH (91.4%)>NaOH (87.4%; PBB (93.8%)>KOH (91.0%; Pglycogen (water-insoluble granules) did not differ among KOH (87.0%), NaOH (87.6%), and BB (86.0%; P=0.81), but recoveries for all were below 90%. Differences among substrates in the need for gelatinization and susceptibility to destruction by alkali likely affected the results. In conclusion, KOH and NaOH glycogen methods provided comparable determinations of fermentation pellet α-glucan. The tests on purified α-glucans indicated that assessment of recovery in glycogen methods can differ by the control α-glucan selected. Published by Elsevier B.V.

  18. Isolation and characterization of bioactive metabolites producing marine Streptomyces parvulus strain sankarensis-A10

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    Mobeen Shaik

    2017-06-01

    Full Text Available The significance and frequency of marine microorganisms as producers of bioactive metabolites-a natural source of drug discovery had varied significantly during the last decades, making marine ecosystem a huge treasure trove of novel isolates and novel compounds. Among the twelve actinomycetes isolated from marine sediment sample (Lat. 17°41′962″N, Long. 83°19′633″E, amylase, protease, lipase and cellulase activities were exhibited by 8,7,4,3 isolates respectively. Five isolates exhibited l-asparaginase activity, while 5, 6, 2 isolates exhibited antibacterial, antifungal and antimicrobial activities respectively. One isolate VMS-A10 efficiently producing alpha-amylase (25.53 ± 0.50 U/mL, protease (19.26 ± 0.25 U/mL, lipase (36.25 ± 0.10 U/mL, cellulase (14.43 ± 0.513 U/mL, l-asparaginase (0.125 ± 0.004 U/mL, antimicrobial metabolites against B. subtilis (503.33 ± 5.77 U/mL, S. aureus (536.66 ± 5.77 U/mL, E. coli (533.33 ± 5.77 U/mL, P. aeruginosa (500.00 ± 10.0 U/mL, MRSA (538.33 ± 5.77 U/mL, C. albicans (353.33 ± 11.54 U/mL and A. niger (443.33 ± 15.27 U/mL was selected, identified on the basis of morphological, cultural, physiological, and biochemical properties together with 16S rDNA sequence, designated as Streptomyces parvulus strain sankarensis-A10 and sequencing product (1490 bp was deposited in the GenBank database under accession number KT906299, Culture Deposit No: NCIM-5601. Isolation and characterization of each potential actinobacteria having immense industrial and therapeutic value on an unprecedented scale from marine sediments of Visakhapatnam coast will have a burgeoning effect.

  19. Description of two Enterococcus strains isolated from traditional Peruvian artisanal-produced cheeses with a bacteriocin-like inhibitory activity

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    Aguilar Galvez A.

    2009-01-01

    Full Text Available The aim of this work was to isolate and to characterize strains of lactic acid bacteria (LAB with bacteriocin-like inhibitory activity from 27 traditional cheeses artisanal-produced obtained from different Peruvian regions. Twenty Gram+ and catalasenegative strains among 2,277 isolates exhibited bacteriocin-like inhibitory activity against Listeria monocytogenes CWBIB2232 as target strain. No change in inhibitory activity was observed after organic acid neutralization and treatment with catalase of the cell-free supernatant (CFS. The proteinic nature of the antimicrobial activity was confirmed for the twenty LAB strains by proteolytic digestion of the CFS. Two strains, CWBI-B1431 and CWBI-B1430, with the best antimicrobial activity were selected for further researches. These strains were taxonomically identified by phenotypic and genotypic analyses as Enterococcus mundtii (CWBI-B1431 and Enterococcus faecium (CWBI-B1430. The two strains were sensitive to vancomycin (MIC 2 μg.ml-1 and showed absence of haemolysis.

  20. Insights from the genome of a high alkaline cellulase producing Aspergillus fumigatus strain obtained from Peruvian Amazon rainforest.

    Science.gov (United States)

    Paul, Sujay; Zhang, Angel; Ludeña, Yvette; Villena, Gretty K; Yu, Fengan; Sherman, David H; Gutiérrez-Correa, Marcel

    2017-06-10

    Here, we report the complete genome sequence of a high alkaline cellulase producing Aspergillus fumigatus strain LMB-35Aa isolated from soil of Peruvian Amazon rainforest. The genome is ∼27.5mb in size, comprises of 228 scaffolds with an average GC content of 50%, and is predicted to contain a total of 8660 protein-coding genes. Of which, 6156 are with known function; it codes for 607 putative CAZymes families potentially involved in carbohydrate metabolism. Several important cellulose degrading genes, such as endoglucanase A, endoglucanase B, endoglucanase D and beta-glucosidase, are also identified. The genome of A. fumigatus strain LMB-35Aa represents the first whole sequenced genome of non-clinical, high cellulase producing A. fumigatus strain isolated from forest soil. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Isolation and characterisation of an enterocin P-producing Enterococcus lactis strain from a fresh shrimp (Penaeus vannamei).

    Science.gov (United States)

    Ben Braïek, Olfa; Ghomrassi, Hamdi; Cremonesi, Paola; Morandi, Stefano; Fleury, Yannick; Le Chevalier, Patrick; Hani, Khaled; Bel Hadj, Omrane; Ghrairi, Taoufik

    2017-06-01

    Screening for lactic acid bacteria (LAB) from fresh shrimp samples (Penaeus vannamei) collected from retail seafood markets in the Tunisian's coast, resulted in the isolation of an Enterococcus strain termed Q1. This strain was selected for its antagonistic activity against pathogenic bacteria such as Listeria monocytogenes, Pseudomonas aeruginosa, Lactococcus garvieae and against fungi (Aspergillus niger and Fusarium equiseti). The Q1 strain was characterised using standard morphological and biochemical tests, growth assays at different temperatures, pH and salinity. 16S rRNA, rpoA and pheS gene sequencing, as well as the 16S-23S rRNA intergenic spacer analyses, were combined to identify strain Q1 as a strain of Enterococcus lactis. The bacteriocin produced by E. lactis Q1 is thermostable, active in the pH range from 4.0 to 9.0 and has a bactericidal mode of action. The enterocin P structural gene was detected by specific PCR in strain E. lactis Q1, which is in good agreement with SDS-PAGE data of the purified bacteriocin. A lack of significant antibiotic resistance genes and virulence determinants was confirmed by specific PCRs. This work provides the first description of an enterocin P producer E. lactis strain isolated from a fresh shrimp. Based on its safety properties (absence of haemolytic activity, virulence factors and antibiotic resistance genes), this strain has the potential to be used as a natural additive or adjunct protective culture in food biopreservation and/or probiotic culture.

  2. Induction of bacteriocin production by coculture is widespread among plantaricin-producing Lactobacillus plantarum strains with different regulatory operons.

    Science.gov (United States)

    Maldonado-Barragán, Antonio; Caballero-Guerrero, Belén; Lucena-Padrós, Helena; Ruiz-Barba, José Luis

    2013-02-01

    We describe the bacteriocin-production phenotype in a group of eight singular bacteriocinogenic Lactobacillus plantarum strains with three distinct genotypes regarding the plantaricin locus. Genotyping of these strains revealed the existence of two different plantaricin-production regulatory operons, plNC8-plNC8HK-plnD or plnABCD, involving three-component systems controlled each of them by a specific autoinducer peptide (AIP), i.e. PLNC8IF or PlnA. While all of the strains produced antimicrobial activity when growing on solid medium, most of them halted this production when cultured in broth, thus reflecting the functionality of regulatory mechanisms. Antimicrobial activity in broth cultures was re-established or enhanced when the specific AIP was added to the culture or by coculturing with specific bacterial strains. The latter trait appeared to be widespread in bacteriocinogenic L. plantarum strains independently of the regulatory system used to regulate bacteriocin production or the specific bacteriocins produced. The induction spectrum through coculture, i.e. the pattern of bacterial strains able to induce bacteriocin production, was characteristic of each individual L. plantarum strain. Also, the ability of some bacteria to induce bacteriocin production in L. plantarum by coculture appeared to be strain specific. The fact that induction of bacteriocin production by coculturing appeared to be a common feature in L. plantarum can be exploited accordingly to enhance the viability of this species in food and feed fermentations, as well as to contribute to probiotic functionality when colonising the gastrointestinal tract. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings

    Science.gov (United States)

    Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their...

  4. Structural characterization of bioengineered α-D-glucans produced by mutant glucansucrase GTF180 enzymes of lactobacillus reuteri strain 180

    NARCIS (Netherlands)

    Leeuwen, S.S. van; Kralj, S.; Eeuwema, W.; Gerwig, G.J.; Dijkhuizen, L.; Kamerling, J.P.

    2009-01-01

    Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

  5. Structural Characterization of Bioengineered alpha-D-Glucans Produced by Mutant Glucansucrase GTF180 Enzymes of Lactobacillus reuteri Strain 180

    NARCIS (Netherlands)

    van Leeuwen, Sander S.; Kralj, Slavko; Eeuwema, Wieger; Gerwig, Gerrit J.; Dijkhuizen, Lubbert; Kamerling, Johannis P.

    Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

  6. [An Efficient Method for Genetic Certification of Bacillus subtilis strains, Prospective Producers of Biopreparations].

    Science.gov (United States)

    Terletskiy, V P; Tyshenko, V I; Novikova, I I; Boikova, I V; Tyulebaev, S D; Shakhtamirov, I Ya

    2016-01-01

    Genetic certification of commercial strains of bacteria antagonistic to phytopathogenic microorganisms guarantees their unequivocal identification and confirmation of safety. In Russia, unlike EU countries, genetic certification of Bacillus subtilis strains is not used. Based on the previously proposed double digestion selective label (DDSL) fingerprinting, a method for genetic identification and certification of B. subtilis strains was proposed. The method was tested on several strains differing in their physiological and biochemical properties and in the composition of secondary metabolites responsible for the spectrum of antibiotic activity. High resolving power of this approach was shown. Optimal restriction endonucleases (SgsI and Eco32I) were determined and validated. A detailed protocol for genetic certification of this bacterial species was developed. DDSL is a universal method, which may be adapted for genetic identification and certification of other bacterial species.

  7. Growth kinetic and fuel quality parameters as selective criterion for screening biodiesel producing cyanobacterial strains.

    Science.gov (United States)

    Gayathri, Manickam; Shunmugam, Sumathy; Mugasundari, Arumugam Vanmathi; Rahman, Pattanathu K S M; Muralitharan, Gangatharan

    2018-01-01

    The efficiency of cyanobacterial strains as biodiesel feedstock varies with the dwelling habitat. Fourteen indigenous heterocystous cyanobacterial strains from rice field ecosystem were screened based on growth kinetic and fuel parameters. The highest biomass productivity was obtained in Nostoc punctiforme MBDU 621 (19.22mg/L/day) followed by Calothrix sp. MBDU 701 (13.43mg/L/day). While lipid productivity and lipid content was highest in Nostoc spongiaeforme MBDU 704 (4.45mg/L/day and 22.5%dwt) followed by Calothrix sp. MBDU 701 (1.54mg/L/day and 10.75%dwt). Among the tested strains, Nostoc spongiaeforme MBDU 704 and Nostoc punctiforme MBDU 621 were selected as promising strains for good quality biodiesel production by Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Genomic analysis of thermophilic Bacillus coagulans strains: efficient producers for platform bio-chemicals.

    Science.gov (United States)

    Su, Fei; Xu, Ping

    2014-01-29

    Microbial strains with high substrate efficiency and excellent environmental tolerance are urgently needed for the production of platform bio-chemicals. Bacillus coagulans has these merits; however, little genetic information is available about this species. Here, we determined the genome sequences of five B. coagulans strains, and used a comparative genomic approach to reconstruct the central carbon metabolism of this species to explain their fermentation features. A novel xylose isomerase in the xylose utilization pathway was identified in these strains. Based on a genome-wide positive selection scan, the selection pressure on amino acid metabolism may have played a significant role in the thermal adaptation. We also researched the immune systems of B. coagulans strains, which provide them with acquired resistance to phages and mobile genetic elements. Our genomic analysis provides comprehensive insights into the genetic characteristics of B. coagulans and paves the way for improving and extending the uses of this species.

  9. Strain improvement in Streptomyces galilaeus, a producer of anthracycline antibiotics galirubins

    International Nuclear Information System (INIS)

    Kralovcova, E.; Blumauerova, M.; Vanek, Z.

    1977-01-01

    The production of epsilon-pyrromycinone glycosides in Streptomyces galilaeus increased 12-fold, with respect to the wild strain, as a result of a sequential procedure including both natural selection and treatment with mutagens (nitrous acid, UV light and γ irradiation). Nitrous acid exhibited the highest mutagenic effect, both in increasing the productivity and in inducing blocked mutants. A mutant strain blocked in the biosynthesis of glycosides and accumulating free epsilon-pyrromycinone as the principal metabolite was obtained. (author)

  10. Immune Modulating Capability of Two Exopolysaccharide-Producing Bifidobacterium Strains in a Wistar Rat Model

    Directory of Open Access Journals (Sweden)

    Nuria Salazar

    2014-01-01

    Full Text Available Fermented dairy products are the usual carriers for the delivery of probiotics to humans, Bifidobacterium and Lactobacillus being the most frequently used bacteria. In this work, the strains Bifidobacterium animalis subsp. lactis IPLA R1 and Bifidobacterium longum IPLA E44 were tested for their capability to modulate immune response and the insulin-dependent glucose homeostasis using male Wistar rats fed with a standard diet. Three intervention groups were fed daily for 24 days with 10% skimmed milk, or with 109 cfu of the corresponding strain suspended in the same vehicle. A significant increase of the suppressor-regulatory TGF-β cytokine occurred with both strains in comparison with a control (no intervention group of rats; the highest levels were reached in rats fed IPLA R1. This strain presented an immune protective profile, as it was able to reduce the production of the proinflammatory IL-6. Moreover, phosphorylated Akt kinase decreased in gastroctemius muscle of rats fed the strain IPLA R1, without affecting the glucose, insulin, and HOMA index in blood, or levels of Glut-4 located in the membrane of muscle and adipose tissue cells. Therefore, the strain B. animalis subsp. lactis IPLA R1 is a probiotic candidate to be tested in mild grade inflammation animal models.

  11. The prevalence of methicillin-resistant Staph. aureus strains producing enterotoxin A and B

    Directory of Open Access Journals (Sweden)

    Safiyeh Abbasi

    2016-02-01

    Full Text Available Background: Staphylococcus aureus is a gram positive coccus which is able to cause different kinds of infection in certain condition. The function of this bacteria is to provide the conditions for the invasion of it to the host with the secretion of different sorts of toxins such as Staphylococcus aureus enterotoxin, including important virulence factors that super antigens are all factors digestive inconvenience. Staphylococcus aureus enterotoxin-secreting toxins such conditions provides invasion of host genes. There are different types of SE, but type A enterotoxin (SEA and type B enterotoxin (SEB are the most important types. Therefore, in this study, the prevalence of Staphylococcus aureus toxin-producing enterotoxin genes (SEB, SEA in clinical strains isolated from patients in teaching hospitals of Shahrekord city, Iran, were studied. Methods: This cross-sectional and descriptive study, which was conducted from May 2014 to December 2014. A hundred and ten isolates of Staphylococcus aureus from patients collected over a period of 8 months and were first identified using standard biochemical methods and laboratory. Using standard methods and laboratory tests were identified and compared with the antibiotic oxacillin minimum inhibitory concentration were determined by broth micro dilution, and then they were assessed by polymerase chain reaction (PCR technique. Results: The results indicated that, 110 samples of dairy products infected by Staphylococcus aureus were detected. Two cases (1.8% of these infected samples were carrying both enterotoxin A and enterotoxin B genes. The frequencies of enterotoxin A genes were twenty-six cases (23/6% and The frequencies of enterotoxin B genes were two cases (1/8%, respectively. Conclusion: The detection of enterotoxin A and enterotoxin B genes, shows the most important role they have in bringing about superinfection. The detection of enterotoxin A and B genes, shows the most important role they have in

  12. The effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on model bacterial strains and isolates from industrial wastewater.

    Science.gov (United States)

    Vasileva-Tonkova, Evgenia; Sotirova, Anna; Galabova, Danka

    2011-02-01

    In this study, the effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on bacterial strains, laboratory strains, and isolates from industrial wastewater was investigated. It was shown that biosurfactant, depending on the concentration, has a neutral or detrimental effect on the growth and protein release of model Gram (+) strain Bacillus subtilis 168. The growth and protein release of model Gram (-) strain Pseudomonas aeruginosa 1390 was not influenced by the presence of biosurfactant in the medium. Rhamnolipid biosurfactant at the used concentrations supported the growth of some slow growing on hexadecane bacterial isolates, members of the microbial community. Changes in cell surface hydrophobicity and permeability of some Gram (+) and Gram (-) isolates in the presence of rhamnolipid biosurfactant were followed in experiments in vitro. It was found that bacterial cells treated with biosurfactant became more or less hydrophobic than untreated cells depending on individual characteristics and abilities of the strains. For all treated strains, an increase in the amount of released protein was observed with increasing the amount of biosurfactant, probably due to increased cell permeability as a result of changes in the organization of cell surface structures. The results obtained could contribute to clarify the relationships between members of the microbial community as well as suggest the efficiency of surface properties of rhamnolipid biosurfactant from Pseudomonas fluorescens making it potentially applicable in bioremediation of hydrocarbon-polluted environments.

  13. Isolation and characterization of biosurfactant-producing Alcanivorax strains: hydrocarbon accession strategies and alkane hydroxylase gene analysis.

    Science.gov (United States)

    Olivera, Nelda L; Nievas, Marina L; Lozada, Mariana; Del Prado, Guillermo; Dionisi, Hebe M; Siñeriz, Faustino

    2009-01-01

    Biosurfactant-producing bacteria belonging to the genera Alcanivorax, Cobetia and Halomonas were isolated from marine sediments with a history of hydrocarbon exposure (Aristizábal and Gravina Peninsulas, Argentina). Two Alcanivorax isolates were found to form naturally occurring consortia with strains closely related to Pseudomonas putida and Microbacterium esteraromaticum. Alkane hydroxylase gene analysis in these two Alcanivorax strains resulted in the identification of two novel alkB genes, showing 86% and 60% deduced amino acid sequence identity with those of Alcanivorax sp. A-11-3 and Alcanivorax dieselolei P40, respectively. In addition, a gene homologous to alkB2 from Alcanivorax borkumensis was present in one of the strains. The consortium formed by this strain, Alcanivorax sp. PA2 (98.9% 16S rRNA gene sequence identity with A. borkumensis SK2(T)) and P. putida PA1 was characterized in detail. These strains form cell aggregates when growing as mixed culture, though only PA2 was responsible for biosurfactant activity. During exponential growth phase of PA2, cells showed high hydrophobicity and adherence to hydrocarbon droplets. Biosurfactant production was only detectable at late growth and stationary phases, suggesting that it is not involved in initiating oil degradation and that direct interfacial adhesion is the main hydrocarbon accession mode of PA2. This strain could be useful for biotechnological applications due to its biosurfactant production, catabolic and aggregation properties.

  14. Typing clinical and animal environment Aspergillus fumigatus gliotoxin producer strains isolated from Brazil by PCR-RFLP markers.

    Science.gov (United States)

    Soleiro, C A; Pena, G A; Cavaglieri, L R; Coelho, I; Keller, L M; Dalcero, A M; Rosa, C A R

    2013-12-01

    Aspergillus fumigatus, a well-known human and animal pathogen causing aspergillosis, has been historically identified by morphological and microscopic features. However, recent studies have shown that species identification on the basis of morphology alone is problematic. The aim of this work was to confirm the taxonomic state at specie level of a set of clinical (human and animal) and animal environment A. fumigatus strains identified by morphological criteria applying a PCR-RFLP assay by an in silico and in situ analysis with three restriction enzymes. The A. fumigatus gliotoxin-producing ability was also determined. Previous to the in situ PCR-RFLP analysis, an in silico assay with BccI, MspI and Sau3AI restriction enzymes was carried out. After that, these enzymes were used for in situ assay. All A. fumigatus strains isolated from corn silage, human aspergillosis and bovine mastitis and high per cent of the strains isolated from cereals, animal feedstuff and sorghum silage were able to produce high gliotoxin levels. Also, all these strains identified by morphological criteria as A. fumigatus, regardless of its isolation source, had band patterns according to A. fumigatus sensu stricto by PCR-RFLP markers. Aspergillus fumigatus is a well-known human and animal pathogen causing aspergillosis. In this study, clinical (human and animal) and animal environment strains were able to produce high gliotoxin levels and had band profiles according to A. fumigatus sensu stricto by PCR-RFLP markers. The results obtained here suggest that strains involved in human and animal aspergillosis could come from the animal environment in which A. fumigatus is frequently found. Its presence in animal environments could affect animal health and productivity; in addition, there are risks of contamination for rural workers during handling and storage of animal feedstuffs. © 2013 The Society for Applied Microbiology.

  15. ANOMALOUS BLUE COLOURING OF MOZZARELLA CHEESE INTENTIONALLY CONTAMINATED WITH PIGMENT PRODUCING STRAINS OF PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    P. Sechi

    2011-04-01

    Full Text Available In summer 2010 a large outbreak of anomalous blue coloration of mozzarella cheese was recorded in Italy and some northern European countries. Official laboratory analysis and health authorities linked the outbreak to the contamination of processing water with strains of Pseudomonas fluorescens, although several expert raised the question of how to unequivocally link the blue coloring to the presence of the micro-organism. In an attempt to set-up a method to determine whether a given Pseudomonas spp. strain is responsible of the defect, an in vitro system for the evaluation of blue colouring of mozzarella cheese intentionally contaminated with strains of Pseudomonas fluorescens. was developed The system is aimed to ascertain whether P. fluorescens strains, isolated from mozzarella cheese with anomalous blue coloration, are able to reproduce the blue coloration under controlled experimental condition. 96 trials of experimental inoculation of mozzarella cheese in different preservation liquids, were conducted using various suspension of Pseudomonas spp. (P. fluorescens ATCC 13525, P. fluorescens CFBP 3150, one P. fluorescens field strain isolated from blue-colored mozzarella cheese and P. aeruginosa ATCC 10145 as positive control at different concentrations and incubated at different temperatures. Growth curve of all Pseudomonas spp. strains tested demonstrated that after three days of incubation the concentration was generally higher than 106 CFU/g of mozzarella cheese incubated in Tryptic Soy Broth (TSB, and higher than 105 CFU/g of mozzarella cheese incubated in preservation liquid. All mozzarella cheeses inoculated with the field strain of Pseudomonas fluorescens showed the characteristic anomalous blue coloration, which is often associated with Pseudomonas fluorescens contamination of water used during mozzarella cheesemaking. With the proposed system, which enabled a considerable amount of samples to be analysed under controlled experimental

  16. [Co-occurence of indol-producing bacterial strains in the vagina of women infected with Chlamydia trachomatis].

    Science.gov (United States)

    Romanik, Małgorzata; Martirosian, Gayane; Wojciechowska-Wieja, Anna; Cieślik, Katarzyna; Kaźmierczak, Wojciech

    2007-08-01

    The aim of this study was to determine if cervicitis, caused by Chlamydia trachomatis (C. trachomatis), has an influence on the frequency of occurrence of selected aerobic and anaerobic bacterial strains, connected with etiology of aerobic vaginitis (AV) and bacterial vaginosis (BV). Indole-producing bacteria have received particular attention due to their possibly inductive role in chronic cervicitis caused by C. trachomatis. The swabs from vagina and cervical canal have been obtained from 122 women (aged 18-40). The presence of C. trachomatis antigen had been detected and diagnosed with the help of direct immunofluorescence, BV with Amesl and Nugent criteria, whereas the AV with Donders criteria. The identification of the bacterial strains isolated from vagina has been performed according to classical microbiological diagnostics. Disruption of vaginal microflora (4-10 in Nugent score) was determined in 11,5% of observed women. AV was diagnosed in 4.5% women with chlamydial cervicitis, BV was diagnosed in 10.9% and 5.45% of these women, on the basis of Amsel and Nugent criteria respectively. Indole-producing bacterial strains connected with BV and AV (Peptostreptococcus anaerobius, Propionibacterium acnes, Escherichia coli) have been isolated significantly more often from vagina of women infected with C trachomatis (p = 0.0405, chi2 = 4.20) and these findings confirm co-importance of indole-producing bacterial strains in cervicitis caused by C trachomatis .

  17. Obtaining mutants of Streptomyces griseoflavus strain 1339, producers of glucose isomerase, following gamma irradiation

    International Nuclear Information System (INIS)

    Dzhedzheva, G.; Stoeva, N.; Stojchev, M.

    1990-01-01

    A water suspension of Streptomyces griseoflavus strain 1339 spores of a density of 8.7.10 6 spores/cm 3 is gamma irradiated ( 60 Co, RHM-γ-20, 30.3 Gy/min). The survival of Streptomyces griseoflavus strain 1339 spores was determined depending on radiation doses, exposure times and incubation temperature. Five major morphological types of colonies were isolated, characterized by different levels of glucose isomerase activity. Maximum specific glucose isomerase activity (GIU/g) was attained after the third gamma irradiation step using a dose of 3000 Gy. 2 tabs., 3 figs., 7 refs

  18. Helicusin E, isochromophilone X and isochromophilone XI: new chloroazaphilones produced by the fungus Bartalinia robillardoides strain LF550.

    Science.gov (United States)

    Jansen, Nils; Ohlendorf, Birgit; Erhard, Arlette; Bruhn, Torsten; Bringmann, Gerhard; Imhoff, Johannes F

    2013-03-12

    Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1) and deacetylsclerotiorin (2)), three new chloroazaphilones (helicusin E (3); isochromophilone X (4) and isochromophilone XI (5)) and one new pentaketide (bartanolide (6)) were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.

  19. Helicusin E, Isochromophilone X and Isochromophilone XI: New Chloroazaphilones Produced by the Fungus Bartalinia robillardoides Strain LF550

    Directory of Open Access Journals (Sweden)

    Johannes F. Imhoff

    2013-03-01

    Full Text Available Microbial studies of the Mediterranean sponge Tethya aurantium led to the isolation of the fungus Bartalinia robillardoides strain LF550. The strain produced a number of secondary metabolites belonging to the chloroazaphilones. This is the first report on the isolation of chloroazaphilones of a fungal strain belonging to the genus Bartalinia. Besides some known compounds (helicusin A (1 and deacetylsclerotiorin (2, three new chloroazaphilones (helicusin E (3; isochromophilone X (4 and isochromophilone XI (5 and one new pentaketide (bartanolide (6 were isolated. The structure elucidations were based on spectroscopic analyses. All isolated compounds revealed different biological activity spectra against a test panel of four bacteria: three fungi; two tumor cell lines and two enzymes.

  20. Irradiation studies of local Streptomyces strains for higher antibiotic producing capacity. Part of a coordinated programme on radiation microbiology

    International Nuclear Information System (INIS)

    Kintanar, Q.L.

    1978-06-01

    The 14 mutants produced by sequential exposure to gamma and ultraviolet irradiation were found to belong to different fundamental types of variants differing in morphology, stability, and metabolite spectra from the parent strain. The first hour mutants, M-1 to M-4 could be considered as belonging to the first category of mutants. Metabolites produced were the same as the parent but differ only in quantity. One was a morphological mutant, M-4 which differed from the parent strain in the production of a brown pigment and conidia, and lack of aerial mycelium. It was found to be most stable and capable of producing high antibiotic yield. The rest of the mutants, M-5 to M-14 could be grouped in the second category. The synthesis of one or more metabolites of the parent strain has been lost by mutation. Unexpectedly, a mutant, M-9 instead of synthesizing either oxytetracycline or tetracycline produced chlortetracycline. Coconut water was found inhibitory to the production of antibiotics by the parent strain and the high and low producing mutants. Modifying the medium by incorporating phosphate and adjusting the initial pH to 4.75 raised the antibiotic yield of the 10% coconut water supplemented medium of M-4 more than the control. Higher pH than the optimum shortened the lag phase but reduced the antibiotic yield while a lower initial pH prevented the growth of the organism giving negligible yield. A reduction of pH to pH 4.5 for the initial 48 hours lengthened the lag phase with almost no adverse effect on the yield. The incorporation of large amounts of coconut water aggravated the amino acid imbalance of the medium

  1. Supplementary Material for: In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

    KAUST Repository

    Motwalli, Olaa Amin

    2017-01-01

    Abstract Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Results Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis

  2. Draft Genome Sequence of the Tyramine Producer Enterococcus durans Strain IPLA 655

    Science.gov (United States)

    Ladero, Victor; Linares, Daniel M.; del Rio, Beatriz; Fernandez, Maria; Martin, M. Cruz

    2013-01-01

    We here report a 3.059-Mbp draft assembly for the genome of Enterococcus durans strain IPLA 655. This dairy isolate provides a model for studying the regulation of the biosynthesis of tyramine (a toxic compound). These results should aid our understanding of tyramine production and allow tyramine accumulation in food to be reduced. PMID:23682153

  3. Potential application of cyclic lipopeptide biosurfactants produced by Bacillus subtilis strains in laundry detergent formulations.

    Science.gov (United States)

    Mukherjee, A K

    2007-09-01

    Crude cyclic lipopeptide (CLP) biosurfactants from two Bacillus subtilis strains (DM-03 and DM-04) were studied for their compatibility and stability with some locally available commercial laundry detergents. CLP biosurfactants from both B. subtilis strains were stable over the pH range of 7.0-12.0, and heating them at 80 degrees C for 60 min did not result in any loss of their surface-active property. Crude CLP biosurfactants showed good emulsion formation capability with vegetable oils, and demonstrated excellent compatibility and stability with all the tested laundry detergents. CLP biosurfactants from B. subtilis strains act additively with other components of the detergents to further improve the wash quality of detergents. The thermal resistance and extreme alkaline pH stability of B. subtilis CLP biosurfactants favour their inclusion in laundry detergent formulations. This study has great significance because it is already known that microbial biosurfactants are considered safer alternative to chemical or synthetic surfactants owing to lower toxicity, ease of biodegradability and low ecological impact. The present study provides further evidence that CLP biosurfactants from B. subtilis strains can be employed in laundry detergents.

  4. Noble strain of Sparassis latifolia produces high content of β-glucan

    Directory of Open Access Journals (Sweden)

    Dong Ju Lee

    2015-08-01

    Conclusions: These results indicate that the nucleotide sequences and the amino acid sequences of RPB2 can be used to identify individual Sparassis sp. The Sparassis strain CLM1 may be best for developing a remedy to prevent or treat cancer and other chronic diseases.

  5. Fatal necrotizing fasciitis due to necrotic toxin-producing Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    C. Gallois

    2015-11-01

    Full Text Available We report a fatal case of necrotizing soft tissues infection caused by an Escherichia coli strain belonging to phylogenetic group C and harbouring numerous virulence factors reported to be part of a pathogenicity island (PAI such as PAI IIJ96 and conserved virulence plasmidic region.

  6. Production, extraction and characterization of exopolysaccharides produced by the native Leuconostoc pseudomesenteroides R2 strain

    Directory of Open Access Journals (Sweden)

    Elinalva M. Paulo

    2012-06-01

    Full Text Available The genus Leuconostoc belongs to a group of lactic acid bacteria usually isolated from fermented vegetables, which includes species involved in the production of exopolysaccharides (EPS. These biopolymers possess considerable commercial potential. Because of the wide variety of industrial applications of EPS, this study aimed to produce and characterize the native exopolysaccharide strain Leuconostoc pseudomesenteroides R2, which was isolated from cabbage collected in a semi-arid region of Bahia. We employed the following conditions for the production of EPS: 10.7% sucrose, pH 8.2, without agitation and incubation at 28ºC for 30 hours. The fermentation broth was treated with ethanol and generated two types of polysaccharide substances (EPS I and EPS II. The identification of EPS I and EPS II was conducted using FT-IR, ¹H, 13C and DEPT-135 NMR spectra. The two substances were identified as linear dextran α polysaccharides (1 → 6 which indicated different characteristics with respect to thermal analysis and density of free packaging, viscosity and time of solubilization. Both dextrans are of low density, possess high thermal stability and exhibited the behavior characteristic of pseudoplastic polymers.O gênero Leuconostoc pertence a um grupo de bactérias lácticas normalmente isoladas de vegetais fermentados, que inclui espécies envolvidas na produção de exopolissacarídeos (EPS. Esses biopolímeros possuem potencial comercial considerável. Devido à grande variedade de aplicações industriais, de EPS, o presente estudo teve como objetivo produzir e caracterizar o nativo exopolissacarídeo cepa Leuconostoc pseudomesenteroides R2, que foi isolado de repolho coletado em uma região semi-árida da Bahia. Utilizamos as seguintes condições para a produção de EPS: 10,7% de sacarose, pH 8,2, sem agitação e incubação a 28º C por 30 horas. O caldo fermentado foi tratado com etanol, gerando dois tipos de substâncias de polissacar

  7. Techno-functional differentiation of two vitamin B12 producing Lactobacillus plantarum strains: an elucidation for diverse future use.

    Science.gov (United States)

    Bhushan, Bharat; Tomar, S K; Chauhan, Arun

    2017-01-01

    An appropriate selection of Lactobacillus strain (probiotic/starter/functional) on the basis of its techno-functional characteristics is required before developing a novel fermented functional food. We compared vitamin B 12 (B 12 , cobalamin) producing Lactobacillus plantarum isolates, BHM10 and BCF20, for functional (vitamin over-production, genomic insight to B 12 structural genes, and probiotic attributes) and technological [milks (skim and soy) fermentation and B 12 bio-fortification] characteristics. Addition of B 12 precursors (5-amonolevulinate and dimethylbenzimidazole) to cobalamin-free fermentation medium increased vitamin production in BHM10, BCF20, and DSM20016 (a positive standard) by 3.4-, 4.4-, and 3.86-folds, respectively. Three important B 12 structural genes were detected in L. plantarum species (strains BHM10 and BCF20) by PCR for the first time. The gene sequences were submitted to NCBI GenBank and found phylogenetically closer to respective sequences in B 12 producing Lactobacillus reuteri strains. During comparative probiotic testing, BCF20 showed significantly higher (p < 0.05 to p < 0.001) gastrointestinal tolerance and cell surface hydrophobicity (p < 0.05) than BHM10. Moreover, only BCF20 was found positive for BSH activity and also exhibited comparatively better antagonistic potential against potent pathogens. Conversely, high acid and bile susceptible strain BHM10 displayed significantly higher soy milk fermentation and resultant B 12 bio-fortification abilities during technological testing. Two B 12 quantification techniques, UFLC and competitive immunoassay, confirmed the in vitro and in situ bio-production of bio-available form of B 12 after BHM10 fermentation. Conclusively, techno-functional differentiation of two B 12 producing strains elucidates their diverse future use; BCF20 either for B 12 over-production (in vitro) or as a probiotic candidate, while BHM10 for cobalamin bio-fortification (in situ) in soy milk.

  8. Cadophora malorum Cs-8-1 as a new fungal strain producing gibberellins isolated from Calystegia soldanella.

    Science.gov (United States)

    You, Young-Hyun; Yoon, Hyeokjun; Kang, Sang-Mo; Woo, Ju-Ri; Choo, Yeon-Sik; Lee, In-Jung; Shin, Jae-Ho; Kim, Jong-Guk

    2013-07-01

    Fourteen endophytic fungi with different colony morphologies were isolated from the roots of Calystegia soldanella. Endophytic fungi isolated from C. soldanella were identified by internal transcribed spacer (ITS) region. To verify plant growth promotion (PGP), culture filtrates of isolated endophytic fungi were treated in Waito-c rice (WR) and C. soldanella seedlings. Culture filtrates of Cs-8-1 fungal strain had advanced PGP activity. The presence of physiologically bioactive gibberellins (GA) GA(1) (1.213 ng ml(-1)), GA(3) (1.292 ng ml(-1)), GA(4) (3.6 ng ml(-1)), GA(7) (1.328 ng ml(-1)), other inactive GA(9) (0.796 ng ml(-1)) and GA(12) (0.417 ng ml(-1)), GA(20) (0.302 ng ml(-1)), GA(24) (1.351 ng ml(-1)), GA(34) (0.076 ng ml(-1)), and GA(53) (0.051 ng ml(-1)) in culture filtrates of Cs-8-1 fungal strain was detected. The Cs-8-1 fungal strain was confirmed as a producer of GAs. Molecular analysis of sequences showed high similarity of 99% to Cadophora malorum. Consequentially, the Cs-8-1 fungal strain was identified as a new C. malorum producing GAs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Atypical patterns of neural infection produced in mice by drug-resistant strains of herpes simplex virus.

    Science.gov (United States)

    Field, H J; Anderson, J R; Wildy, P

    1982-03-01

    Mice inoculated intracerebrally (i.c.) with a mutant strain of HSV were found to develop cataracts 1 to 2 months after inoculation. Cataract formation was subsequently shown to follow an acute retinitis which commenced within 1 week of inoculation. The mutant had been selected for high resistance to the nucleoside analogue acyclovir and has been shown previously to be defective in the induction of thymidine kinase and also to express an altered DNA polymerase. The LD50 for mice inoculated i.c. was greater than 10(5) p.f.u. compared with approx 7 p.f.u. for the parental strain. Studies of virus replication following i.c. inoculation with a sublethal dose of the mutant revealed that only small amounts of infectious virus were produced in the brain, but during a period from 6 to 12 days after inoculation vigorous replication occurred in retinal tissue, producing very high titres of virus.

  10. Enzymic hydrolysis of xylans. I. A high xylanase and beta-xylosidase producing strain of Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Conrad, D.

    1981-01-01

    Aspergillus niger, strain 110.42 (CBS) was selected as a producer of high xylanolytic activities. The time course of xylanase and beta-xylosidase production as well as the effect of pH and temperature on the activity of these enzymes were studied. High-performance liquid chromatography analysis of the enzymic degradation of arabinoxylan showed a nearly complete conversion to pentose sugars. Aspects of using crude xylanase preparations for enzymic saccharification of xylans are discussed.

  11. FIRST REPORT OF METALLO-β-LACTAMASES PRODUCING Enterobacter spp. STRAINS FROM VENEZUELA

    Science.gov (United States)

    Martínez, Dianny; Rodulfo, Hectorina E.; Rodríguez, Lucy; Caña, Luisa E.; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; Donato, Marcos De

    2014-01-01

    Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of bla VIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed bla TEM-1, but only one showed bla CTX-M-15 gene, while no bla SHV was detected. PMID:24553611

  12. Benefits of combinative application of probiotic, enterocin M-producing strain Enterococcus faecium AL41 and Eleutherococcus senticosus in rabbits.

    Science.gov (United States)

    Lauková, Andrea; Simonová, Monika Pogány; Chrastinová, Ľubica; Plachá, Iveta; Čobanová, Klaudia; Formelová, Zuzana; Chrenková, Mária; Ondruška, Ľubomír; Strompfová, Viola

    2016-03-01

    This study presents the effects of the probiotic and enterocin M-producing strain Enterococcus faecium AL41 on microbiota, phagocytic activity (PA), oxidative stress, performance and biochemical parameters when applied individually or in combination with Eleutherococcus senticosus in rabbits. The novelty of the study lies in the use of our non-rabbit-derived strain (AL41 = CCM8558) which produces new enterocin M. Ninety-six post-weaned rabbits (Hyplus breed) aged 5 weeks were divided into three experimental groups, 24 in each: E. senticosus (ES, 30 g/100 kg) in feed, E. faecium AL41 (10(9) CFU/mL marked by rifampicin to differentiate it from other enterococci) in water, and ES + AL. AL41 colonized sufficiently in rabbits to reduce coliforms, staphylococci, pseudomonads and clostridia. Slight decrease in bacteria was also found in the caecum and appendix. Phagocytic activity was significantly increased in the experimental groups compared to the control group (CG) (p < 0.001; p < 0.05). Applications did not evoke oxidative stress. Biochemical parameters in blood and caecal organic acids were slightly influenced. Average daily weight gain was slightly higher in ES and AL + ES. Combinative application of E. faecium with E. senticosus can be beneficial in rabbits. AL41 strain alone and in combination with ES produced reduction in spoilage bacteria; the highest stimulation of PA was in the AL41 + ES group.

  13. Screening of biosurfactant-producing Bacillus strains using glycerol from the biodiesel synthesis as main carbon source.

    Science.gov (United States)

    Sousa, M; Melo, V M M; Rodrigues, S; Sant'ana, H B; Gonçalves, L R B

    2012-08-01

    Glycerol, a co-product of biodiesel production, was evaluated as carbon source for biosurfactant production. For this reason, seven non-pathogenic biosurfactant-producing Bacillus strains, isolated from the tank of chlorination at the Wastewater Treatment Plant at Federal University of Ceara, were screened. The production of biosurfactant was verified by determining the surface tension value, as well as the emulsifying capacity of the free-cell broth against soy oil, kerosene and N-hexadecane. Best results were achieved when using LAMI005 and LAMI009 strains, whose biosurfactant reduced the surface tension of the broth to 28.8 ± 0.0 and 27.1 ± 0.1 mN m(-1), respectively. Additionally, at 72 h of cultivation, 441.06 and 267.56 mg L(-1) of surfactin were produced by LAMI005 and LAMI009, respectively. The biosurfactants were capable of forming stable emulsions with various hydrocarbons, such as soy oil and kerosene. Analyses carried out with high performance liquid chromatography (HPLC) showed that the biosurfactant produced by Bacillus subtilis LAMI009 and LAMI005 was compatible with the commercially available surfactin standard. The values of minimum surface tension and the CMC of the produced biosurfactant indicated that it is feasible to produce biosurfactants from a residual and renewable and low-cost carbon source, such as glycerol.

  14. Unexplored Brazilian oceanic island host high salt tolerant biosurfactant-producing bacterial strains.

    Science.gov (United States)

    da Silva, Fábio Sérgio Paulino; Pylro, Victor Satler; Fernandes, Pericles Leonardo; Barcelos, Gisele Souza; Kalks, Karlos Henrique Martins; Schaefer, Carlos Ernesto Gonçalves Reynaud; Tótola, Marcos Rogério

    2015-05-01

    We aimed to isolate biosurfactant-producing bacteria in high salt conditions from uncontaminated soils on the Brazilian oceanic island, Trindade. Blood agar medium was used for the isolation of presumptive biosurfactant-producing bacteria. Confirmation and measurements of biosurfactant production were made using an oil-spreading method. The isolates were identified by fatty acid profiles and partial 16S rRNA gene sequence analysis. A total of 14 isolates obtained from the 12 soil samples were found to produce biosurfactants. Among them, two isolates stood out as being able to produce biosurfactant that is increasingly active in solutions containing up to 175 g L(-1) NaCl. These high salt tolerant biosurfactant producers are affiliated to different species of the genus Bacillus. Soil organic matter showed positive correlation with the number of biosurfactant-producing bacteria isolated from our different sampling sites. The applied approach successfully recovered and identified biosurfactant-producing bacteria from non-contaminated soils. Due to the elevated salt tolerance, as well as their capacity to produce biosurfactants, these isolates are promising for environmental biotechnological applications, especially in the oil production chain.

  15. Biological characterization of lead-enhanced exopolysaccharide produced by a lead resistant Enterobacter cloacae strain P2B.

    Science.gov (United States)

    Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

    2012-09-01

    A lead resistant bacterial strain isolated from effluent of lead battery manufacturing company of Goa, India has been identified as Enterobacter cloacae strain P2B based on morphological, biochemical characters, FAME profile and 16S rDNA sequence data. This bacterial strain could resist lead nitrate up to 1.6 mM. Significant increase in exopolysaccharide (EPS) production was observed as the production increased from 28 to 108 mg/L dry weight when exposed to 1.6 mM lead nitrate in Tris buffered minimal medium. Fourier-transformed infrared spectroscopy of this EPS revealed presence of several functional groups involved in metal binding viz. carboxyl, hydroxyl and amide groups along with glucuronic acid. Gas chromatography coupled with mass spectrometry analysis of alditol-acetate derivatives of acid hydrolysed EPS produced in presence of 1.6 mM lead nitrate demonstrated presence of several neutral sugars such as rhamnose, arabinose, xylose, mannose, galactose and glucose, which contribute to lead binding hydroxyl groups. Scanning electron microscope coupled with energy dispersive X-ray spectrometric analysis of this lead resistant strain exposed to 1.6 mM lead nitrate interestingly revealed mucous EPS surrounding bacterial cells which sequestered 17 % lead (as weight %) extracellularly and protected the bacterial cells from toxic effects of lead. This lead resistant strain also showed multidrug resistance. Thus these results significantly contribute to better understanding of structure, function and environmental application of lead-enhanced EPSs produced by bacteria. This lead-enhanced biopolymer can play a very important role in bioremediation of several heavy metals including lead.

  16. Effect of cerulenin on fatty acid composition and gene expression pattern of DHA-producing strain Colwellia psychrerythraea strain 34H.

    Science.gov (United States)

    Wan, Xia; Peng, Yun-Feng; Zhou, Xue-Rong; Gong, Yang-Min; Huang, Feng-Hong; Moncalián, Gabriel

    2016-02-06

    Colwellia psychrerythraea 34H is a psychrophilic bacterium able to produce docosahexaenoic acid (DHA). Polyketide synthase pathway is assumed to be responsible for DHA production in marine bacteria. Five pfa genes from strain 34H were confirmed to be responsible for DHA formation by heterogeneous expression in Escherichia coli. The complexity of fatty acid profile of this strain was revealed by GC and GC-MS. Treatment of cells with cerulenin resulted in significantly reduced level of C16 monounsaturated fatty acid (C16:1(Δ9t), C16:1(Δ7)). In contrast, the amount of saturated fatty acids (C10:0, C12:0, C14:0), hydroxyl fatty acids (3-OH C10:0 and 3-OH C12:0), as well as C20:4ω3, C20:5ω3 and C22:6ω3 were increased. RNA sequencing (RNA-Seq) revealed the altered gene expression pattern when C. psychrerythraea cells were treated with cerulenin. Genes involved in polyketide synthase pathway and fatty acid biosynthesis pathway were not obviously affected by cerulenin treatment. In contrast, several genes involved in fatty acid degradation or β-oxidation pathway were dramatically reduced at the transcriptional level. Genes responsible for DHA formation in C. psychrerythraea was first cloned and characterized. We revealed the complexity of fatty acid profile in this DHA-producing strain. Cerulenin could substantially change the fatty acid composition by affecting the fatty acid degradation at transcriptional level. Acyl-CoA dehydrogenase gene family involved in the first step of β-oxidation pathway may be important to the selectivity of degraded fatty acids. In addition, inhibition of FabB protein by cerulenin may lead to the accumulation of malonyl-CoA, which is the substrate for DHA formation.

  17. Screening of physiologically active strain of the filamentous fungi - a producer of a complex of lytic enzymes

    International Nuclear Information System (INIS)

    Kurbatova, E.I.; Sokolova, E.N.; Borshcheva, Yu.A.; Alsivar, S.K.A.; Rimareva, L.V.

    2014-01-01

    Filamentous Aspergillus fungi were studied to obtain a producer of a complex of the enzymes specific to biodegradation of polymers of cellular walls of vegetable and microbic biomass. Strains were selected by the increased biosynthetic ability in relation to the beta-glucanase (BG), chitinase (CT), mannanase (MN), proteases and pectinases. It was estimated during deep cultivation in the environment containing wheat bran. The fullest complex of hydrolytic enzymes (glucanase, MN, CT, protease and a polygalacturonase (PG)), and also the level of enzymatic activities was in the culture liquid obtained as a result of biosynthesis of Aspergillus foetidus 37-4 (S 37-4) strain. For its cultivation the medium containing salts like potassium dihydrogen phosphate, magnesium sulfate and ammonium sulfate in optimum concentration, and also dioses (maltose, sucrose) and polysaccharides (starch, chitin, pectin) was chosen. The greatest zones of hydrolysis are traced during planting S 37-4 in agar medium containing maltose and low methoxyl citrus pectin. As the synthesis inductor of hemicellulase, MN and CT malt sprouts were used, and of PG - not clarified beet bin fibers. Cultivation was carried out on a thermostatically controlled shaker at 30 deg. C for 120 h. Increase of activity of synthesizable enzymes when using low methoxyl citrus pectin as a media part equaled for BG 5-19%, for PG - 25%, when using a maltose for CT - 100%, MN - 29%. To increase biosynthetic ability of S 37-4 as a mutagen 3-staged ultra-violet radiation (wavelength is 265 nanometers) was applied. The obtained 379-K-5 strain surpassed in activity level a parental strain BG - by 84.8%, CT - by 45.0%, MN - by 62.9%, PG - by 89.0%. The following (4th) stage of radiation led to death of the strain. In comparison with a parental S 37-4 the colony of a mutant strain possessed the bigger size and plentiful formation of an air mycelium, ability to sporogenesis was less expressed

  18. Isolation and characterization of large spectrum and multiple bacteriocin-producing Enterococcus faecium strain from raw bovine milk.

    Science.gov (United States)

    Gaaloul, N; ben Braiek, O; Hani, K; Volski, A; Chikindas, M L; Ghrairi, T

    2015-02-01

    To assess the antimicrobial properties of lactic acid bacteria from Tunisian raw bovine milk. A bacteriocin-producing Enterococcus faecium strain was isolated from raw cow milk with activity against Gram-positive and Gram-negative bacteria. Antimicrobial substances produced by this strain were sensitive to proteolytic enzymes and were thermostable and resistant to a broad range of pH (2-10). Mode of action of antimicrobial substances was determined as bactericidal. Maximum activity was reached at the end of the exponential growth phase when checked against Listeria ivanovii BUG 496 (2366.62 AU ml(-1)). However, maximum antimicrobial activity against Pseudomonas aeruginosa 28753 was recorded at the beginning of the exponential growth phase. Enterococcus faecium GGN7 was characterized as free from virulence factors and was susceptible to tested antibiotics. PCR analysis of the micro-organism's genome revealed the presence of genes coding for enterocins A and B. Mass spectrometry analysis of RP-HPLC active fractions showed molecular masses corresponding to enterocins A (4835.77 Da) and B (5471.56 Da), and a peptide with a molecular mass of 3215.5 Da active only against Gram-negative indicator strains. The latter was unique in the databases. Enterococcus faecium GGN7 produces three bacteriocins with different inhibitory spectra. Based on its antimicrobial properties and safety, Ent. faecium GGN7 is potentially useful for food biopreservation. The results suggest the bacteriocins from GGN7 strain could be useful for food biopreservation. © 2014 The Society for Applied Microbiology.

  19. Microcystis aeruginos strain [D-Leu1] Mcyst-LR producer, from Buenos Aires province, Argentina

    Directory of Open Access Journals (Sweden)

    Lorena Rosso

    2014-04-01

    Full Text Available Objective: To show the toxicological and phylogenetic characterization of a native Microcystis aeruginosa (M. aeruginosa strain (named CAAT 2005-3 isolated from a water body of Buenos Aires province, Argentine. Methods: A M. aeruginosa strain was isolated from the drainage canal of the sewage treatment in the town of Pila, Buenos Aires province, Argentina and acclimated to laboratory conditions. The amplification of cpcBA-IGS Phcocyanin (PC, intergenic spacer and flanking regions was carried out in order to build a phylogenetic tree. An exactive/orbitrap mass spectrometer equipped with an electrospray ionization source (Thermo Fisher Scientific, Bremen, Germany was used for the LC/ESI-HRMS microcystins analysis. The number of cell/mL and [D-Leu1] Mcyst-LR production obtained as a function of time was modelled using the Gompertz equation. Results: The phylogenetic analysis showed that the sequence clustered with others M. aeruginosa sequences obtained from NCBI. The first Argentinian strain of M. aeruginosa (CAAT 2005-3 growing under culture conditions maintains the typical colonial architecture of M. aeruginosa with profuse mucilage. M. aeruginosa CAAT 2005-3 expresses a toxin variant, that was identified by LC-HRMS/Orbitrapas as [D-Leu1] microcystin-LR ([M+H]+=1 037.8 m/z. Conclusions: [D-Leu1] microcystin-LR has been also detected in M. aeruginosa samples from Canada, Brazil and Argentina. This work provides the basis for technological development and production of analytical standards of toxins present in our region.

  20. An effective lipid-producing fungal sp. strain DGB1 and its use for ...

    African Journals Online (AJOL)

    2013-08-21

    Aug 21, 2013 ... Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute ... producing biodiesel since they present many advantages ... microalgae, the growth of fungi can be carried out in.

  1. Complete Genome Sequence of the Gamma-Aminobutyric Acid-Producing Strain Streptococcus thermophilus APC151.

    Science.gov (United States)

    Linares, Daniel M; Arboleya, Silvia; Ross, R Paul; Stanton, Catherine

    2017-04-27

    Here is presented the whole-genome sequence of Streptococcus thermophilus APC151, isolated from a marine fish. This bacterium produces gamma-aminobutyric acid (GABA) in high yields and is biotechnologically suitable to produce naturally GABA-enriched biofunctional yogurt. Its complete genome comprises 2,097 genes and 1,839,134 nucleotides, with an average G+C content of 39.1%. Copyright © 2017 Linares et al.

  2. Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria.

    Science.gov (United States)

    Bernat, Przemysław; Paraszkiewicz, Katarzyna; Siewiera, Paulina; Moryl, Magdalena; Płaza, Grażyna; Chojniak, Joanna

    2016-10-01

    Urinary tract infections are a common disease in humans. Therefore, new methods are needed to destroy biofilms that are formed by uropathogens. Iturin A lipopeptides (LPs) C14 and C15 are potent biosurfactants synthetized by the Bacillus subtilis I'1a strain. The biological activity of extracted LPs was confirmed by examining extracts from I'1a cultures against uropathogenic bacteria that had been isolated from biofilms on urinary catheters. Compared with cultures of DSM 3257, which produce surfactin at a relatively low level, the extract obtained from strain I'1a exhibited a greater inhibitory effect against both planktonic and sessile forms of Escherichia coli, Serratia marcescens, Enterobacter cloacae, Proteus mirabilis, Citrobacter freundii and Enterococcus faecalis. Moreover, cyclic LP biosurfactants may disturb the integrity of cytoplasmic membranes; therefore, we investigated the effects of synthetized LPs on fatty acids and phospholipids of B. subtilis. LPs and lipids were analyzed using GC-MS, LC-MS/MS and MALDI-TOF/TOF techniques. Compared with B. subtilis DSM 3257, membranes of the I'1a strain were characterized by an increased amount of anteiso fatty acids and a ten-fold higher ratio of phosphatidylglycerol (PG)-to-phosphatidylethanolamine (PE). Interestingly, in cultures of B. subtilis DSM 3257 supplemented with LP extracts of the I'1a strain, the PG-to-PE ratio was fourfold higher, and the amount of anteiso fatty acids was also increased.

  3. Formation of Highly Twisted Ribbons in a Carboxymethylcellulase Gene-Disrupted Strain of a Cellulose-Producing Bacterium

    Science.gov (United States)

    Sugano, Yasushi; Shoda, Makoto; Sakakibara, Hitoshi; Oiwa, Kazuhiro; Tuzi, Satoru; Imai, Tomoya; Sugiyama, Junji; Takeuchi, Miyuki; Yamauchi, Daisuke

    2013-01-01

    Cellulases are enzymes that normally digest cellulose; however, some are known to play essential roles in cellulose biosynthesis. Although some endogenous cellulases of plants and cellulose-producing bacteria are reportedly involved in cellulose production, their functions in cellulose production are unknown. In this study, we demonstrated that disruption of the cellulase (carboxymethylcellulase) gene causes irregular packing of de novo-synthesized fibrils in Gluconacetobacter xylinus, a cellulose-producing bacterium. Cellulose production was remarkably reduced and small amounts of particulate material were accumulated in the culture of a cmcax-disrupted G. xylinus strain (F2-2). The particulate material was shown to contain cellulose by both solid-state 13C nuclear magnetic resonance analysis and Fourier transform infrared spectroscopy analysis. Electron microscopy revealed that the cellulose fibrils produced by the F2-2 cells were highly twisted compared with those produced by control cells. This hypertwisting of the fibrils may reduce cellulose synthesis in the F2-2 strains. PMID:23243308

  4. Norfloxacin degradation by Bacillus subtilis strains able to produce biosurfactants on a bioreactor scale

    Directory of Open Access Journals (Sweden)

    Jałowiecki Łukasz

    2017-01-01

    Full Text Available The discharge of antibiotics into the environment has become a major concern since this group of pharmaceuticals influence on microbial communities not only by its mode of action, but also because of the risk of a worldwide dispersal of antibiotic resistance genes (ARG. Antibiotics residues have been found in various environments such as waters, sediments, and soils. Moreover, most WWTPs are not designed to treat such kind of pollutants, which remain incompletely removed. Currently, biodegradation processes which involved bacterial strains with increased degradation capabilities is one of the most promising technique. The aim of this study was to evaluate the norfloxacin biodegradation potential of the three Bacillus subtilis strains named T-1, T’-1 and I’-1a on a bioreactor scale. The aerobic degradation was conducted in a 5-liter bioreactor on minimal salts medium in co-metabolic culture supplemented with glucose. The degradation rate of norfloxacin was determined with the HPLC technique. The surface tension was determined using ring method in order to observe the changes in biosurfactants production. Also, the biofilm formation abilities of the bacteria with two quantitative methods, crystal violet (CV method and TTC-based test and enzymes production were evaluated.

  5. Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

    Science.gov (United States)

    Powell, Ryan J.

    2013-01-01

    Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain, Bacillus sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a Nannochloropsis sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of Nannochloropsis oceanica IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s. PMID:23892750

  6. Mutant strain screening by 60Co γ-rays irradiation and its cellulase enzyme produce condition

    International Nuclear Information System (INIS)

    Song Andong; Su Lijuan; Xie Hui; Qu Yinbo; Yang Ming

    2008-01-01

    A mutant strain A50 with high cellulase activity was induced and isolated by using 60 Co γ-rays irradiation from the initial Penicillium decumbens A10. The optimum fermentation conditions of A50 were investigated through orthogonal designing experiment, the major carbon resource 5%, the ratio between wheat bran and corn straw 1:1, the concentration of glucose as supplemental carbon 0.1%, the concentration of (NH 4 ) 2 HPO 4 as supplemental nitrogen resource 0.2%, the initial pH of liquid medium 5.0, the inoculated amount for fermentation 10% and the concentration of Tween-80 0.1%, 30 ml initial media filled in the 300 ml flask with culture condition of 32 degree C and 200 r/min. Under the optimum conditions mentioned above, the highest activities of cellulase and filter paper enzyme were 27.28 and 1.98IU/ml at 60 h fermentation, respectively, which was 33.2% and 45.59% higher than those of the initial strain. (authors)

  7. Characterization of a bacteriocin-like substance produced from a novel isolated strain of Bacillus subtilis SLYY-3

    Science.gov (United States)

    Li, Junfeng; Li, Hongfang; Zhang, Yuanyuan; Duan, Xiaohui; Liu, Jie

    2014-12-01

    In the present research, the strain SLYY-3 was isolated from sediments of Jiaozhou Bay, Qingdao, China. The strain SLYY-3, which produced a bacteriocin-like substance (BLS), was characterized to be a strain of Bacillus subtillis by biochemical profiling and 16S rDNA sequence analysis. It is the first time to report that Bacillus subtilis from Jiaozhou Bay sediments could produce a BLS. The BLS of B. subtillis SLYY-3 exhibited strong inhibitory activity against gram-positive bacteria (including Staphylococcus aureus and B. subtillis) and some fungi (including Penicillium glaucum, Aspergillus niger and Aspergillus flavus). The antimicrobial activity was detected from culture in the exponential growth phase and reached its maximum when culture entered into stationary growth phase. It was thermo-tolerant even when being kept at 100°C for 60 min without losing any activity and stable over a wide pH range from 1.0 to 12.0 while being inactivated by proteolytic enzyme and trypsin, indicating the proteinaceous nature of the BLS. The BLS was purified by precipitation with hydrochloric acid (HCl) and gel filteration (Sephadex G-100). SDS-PAGE analysis of the extracellular peptides of SLYY-3 revealed a bacteriocin-like protein with a molecular mass of 66 kDa. Altogether, these characteristics indicate the potential of the BLS for food industry as a protection against pathogenic and spoilage microorganisms.

  8. Case of Meningitis in a Neonate Caused by an Extended-Spectrum-Beta-Lactamase-Producing Strain of Hypervirulent Klebsiella pneumoniae

    Directory of Open Access Journals (Sweden)

    Khalit S. Khaertynov

    2017-08-01

    Full Text Available Klebsiella pneumoniae is one of the most important infectious agents among neonates. This pathogen has a potential to develop an increased antimicrobial resistance and virulence. The classic non-virulent strain of K. pneumoniae, producing an extended-spectrum beta-lactamases (ESBL, is associated with nosocomial infection mainly in preterm neonates. Hypervirulent K. pneumoniae strains are associated with invasive infection among previously healthy ambulatory patients, and most of them exhibit antimicrobial susceptibility. During the last few years, several cases of diseases caused by hypervirulent K. pneumoniae producing ESBL have been registered in different geographical regions of the world. However, reports of such cases in neonates are rare. Here, we reported that this pathogen can cause pyogenic meningitis in full-term neonate with poor prognosis. A previously healthy, full-term, 12-day-old neonate was admitted to the infectious diseases hospital with suspected meningitis. The clinical symptoms included loss of appetite, irritability, fever, seizures, and a bulging anterior fontanelle. The analysis of the cerebrospinal fluid confirmed the diagnosis of meningitis. Blood and cerebrospinal fluid cultures were positive for K. pneumoniae, producing ESBL. K. pneumoniae isolates were resistant to aminopenicillins, 3rd generation cephalosporins but were sensitive to imipenem and meropenem. The “string test” was positive. The study of the virulence factors of K. pneumoniae by PCR revealed the presence of the rmpA gene. A combination of K. pneumoniae virulence and drug resistance complicated by cerebral oedema led to the death of the neonate. We concluded that both the risk of developing severe forms of infection and the outcome of the disease due to K. pneumonia are associated with the phenotypic features of the pathogen such as its antibiotic susceptibility and virulence factors. Emergence of the ESBL-producing strain of hypervirulent K

  9. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  10. PARTIAL CHARACTERIZATION OF ENZYMATIC ACTIVITIES PRODUCED BY A WILD STRAIN OF A. NIGER

    Directory of Open Access Journals (Sweden)

    María Martos

    2012-12-01

    Full Text Available Aspergillus niger, isolated from decay citrus peels in the province of Misiones, was able to produce pectinases by submerged fermentation. The enzymatic extract exhibited polygalacturonase, pectinesterase and lyase activities. Others enzymes capable of degrading cell wall polymers were also detected in the enzymatic extract such as cellulases and xylanases. Polygalacturonase was an endo-polygalacturonase. The enzyme exhibited a maximal activity at pH range between 4.5 to 5.0, was stable in the pH range from 2.5 to 5.5 and remained unchanged when was incubated at temperatures lower than 50 ºC. The fungi produced three PG isoenzymes. The enzymatic extract was able to clarify apple juice. The results observed make the pectinolytic enzymes produced by A. niger appropriate for future application in fruit juice processing industries.

  11. Identification of thermophilic bacterial strains producing thermotolerant hydrolytic enzymes from manure compost.

    Science.gov (United States)

    Charbonneau, David M; Meddeb-Mouelhi, Fatma; Boissinot, Maurice; Sirois, Marc; Beauregard, Marc

    2012-03-01

    Ten thermophilic bacterial strains were isolated from manure compost. Phylogenetic analysis based on 16S rRNA genes and biochemical characterization allowed identification of four different species belonging to four genera: Geobacillus thermodenitrificans, Bacillus smithii, Ureibacillus suwonensis and Aneurinibacillus thermoaerophilus. PCR-RFLP profiles of the 16S-ITS-23S rRNA region allowed us to distinguish two subgroups among the G. thermodenitrificans isolates. Isolates were screened for thermotolerant hydrolytic activities (60-65°C). Thermotolerant lipolytic activities were detected for G. thermodenitrificans, A. thermoaerophilus and B. smithii. Thermotolerant protease, α-amylase and xylanase activities were also observed in the G. thermodenitrificans group. These species represent a source of potential novel thermostable enzymes for industrial applications.

  12. Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Rinker, Torri E.; Baker, Scott E.

    2007-01-29

    Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism. In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.

  13. Different response to acetic acid stress in Saccharomyces cerevisiae wild-type and l-ascorbic acid-producing strains.

    Science.gov (United States)

    Martani, Francesca; Fossati, Tiziana; Posteri, Riccardo; Signori, Lorenzo; Porro, Danilo; Branduardi, Paola

    2013-09-01

    Biotechnological processes are of increasing significance for industrial production of fine and bulk chemicals, including biofuels. Unfortunately, under operative conditions microorganisms meet multiple stresses, such as non-optimal pH, temperature, oxygenation and osmotic stress. Moreover, they have to face inhibitory compounds released during the pretreatment of lignocellulosic biomasses, which constitute the preferential substrate for second-generation processes. Inhibitors include furan derivatives, phenolic compounds and weak organic acids, among which acetic acid is one of the most abundant and detrimental for cells. They impair cellular metabolism and growth, reducing the productivity of the process: therefore, the development of robust cell factories with improved production rates and resistance is of crucial importance. Here we show that a yeast strain engineered to endogenously produce vitamin C exhibits an increased tolerance compared to the parental strain when exposed to acetic acid at moderately toxic concentrations, measured as viability on plates. Starting from this evidence, we investigated more deeply: (a) the nature and levels of reactive oxygen species (ROS); (b) the activation of enzymes that act directly as detoxifiers of reactive oxygen species, such as superoxide dismutase (SOD) and catalase, in parental and engineered strains during acetic acid stress. The data indicate that the engineered strain can better recover from stress by limiting ROS accumulation, independently from SOD activation. The engineered yeast can be proposed as a model for further investigating direct and indirect mechanism(s) by which an antioxidant can rescue cells from organic acid damage; moreover, these studies will possibly provide additional targets for further strain improvements. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Draft Genome Sequence of the Putrescine-Producing Strain Lactococcus lactis subsp. lactis 1AA59

    Science.gov (United States)

    del Rio, Beatriz; Linares, Daniel M.; Fernandez, María; Mayo, Baltasar; Martín, M. Cruz

    2015-01-01

    We report here the 2,576,542-bp genome annotated draft assembly sequence of Lactococcus lactis subsp. lactis 1AA59. This strain—isolated from a traditional cheese—produces putrescine, one of the most frequently biogenic amines found in dairy products. PMID:26089428

  15. Biochemical characterization of ochratoxin A-producing strains of the genus Penicillium

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Svendsen, Anne; Smedsgaard, Jørn

    2001-01-01

    of P. verrucosum. These isolates produced ochratoxin A, verrucolones, citrinin, and verrucines and had a characteristic dark brown reverse color on yeast extract-sucrose agar medium. Almost all of a group of 20 isolates mainly originating from cheese and meat products had a pale cream reverse color...

  16. Identification of over producer strain of endo-ß-1,4-glucanase in ...

    African Journals Online (AJOL)

    Cellulases are a group of hydrolytic enzymes capable of degrading cellulose to smaller sugar components like glucose units. These enzymes are produced by fungi and bacteria. The aim of this research was to identify a Aspergillus species with over production of endo-β-1,4-glucanase. Properties of endo-β-1 ...

  17. Isolation and identification of phytase-producing strains from soil samples and optimization of production parameters

    Directory of Open Access Journals (Sweden)

    Masoud Mohammadi

    2017-09-01

    Discussion and conclusion: Penicillium sp. isolated from a soil sample near Qazvin, was able to produce highly active phytase in optimized environmental conditions, which could be a suitable candidate for commercial production of phytase to be used as complement in poultry feeding industries.

  18. In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

    KAUST Repository

    Motwalli, Olaa Amin; Essack, Magbubah; Jankovic, Boris R.; Ji, Boyang; Liu, Xinyao; Ansari, Hifzur Rahman; Hoehndorf, Robert; Gao, Xin; Arold, Stefan T.; Mineta, Katsuhiko; Archer, John A.C.; Gojobori, Takashi; Mijakovic, Ivan; Bajic, Vladimir B.

    2017-01-01

    To our knowledge FFASC is the first in silico method to screen cyanobacteria proteomes for their potential to produce and excrete FFA, as well as the first attempt to parameterize the criteria derived from genetic characteristics that are favorable/non-favorable for this purpose. Thus, FFASC helps focus experimental evaluation only on the most promising cyanobacteria.

  19. Structural investigation of an extracellular polysaccharide produced by the cariogenic bacterium Streptococcus mutans strain UA159

    NARCIS (Netherlands)

    Li, Bo; Dobruchowska, Justyna M.; Hoogenkamp, Michel A.; Gerwig, Gerrit J.

    2012-01-01

    The structure of an extracellular polysaccharide EPS159 produced from sucrose by Streptococcus mutans UA159 was investigated through the main oligosaccharides obtained from partial acid hydrolysis, monosaccharide/methylation analysis, and 1D/2D H-1 NMR spectroscopy. The results showed that EPS159

  20. Prevalence and clonal relationship of ESBL-producing Salmonella strains from humans and poultry in northeastern Algeria.

    Science.gov (United States)

    Djeffal, Samia; Bakour, Sofiane; Mamache, Bakir; Elgroud, Rachid; Agabou, Amir; Chabou, Selma; Hireche, Sana; Bouaziz, Omar; Rahal, Kheira; Rolain, Jean-Marc

    2017-05-15

    The aims of this study were to investigate Salmonella contamination in broiler chicken farms and slaughterhouses, to assess the antibiotic resistance profile in avian and human Salmonella isolates, and to evaluate the relationship between avian and human Extended Spectrum β-Lactamase (ESBL)-producing isolates. Salmonella was screened in different sample matrices collected at thirty-two chicken farms and five slaughterhouses. The human isolates were recovered from clinical specimens at the University Teaching Hospital of Constantine (UTH). All suspected colonies were confirmed by MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time OF light) and serotyped. Susceptibility testing against 13 antibiotics including, amoxicillin/clavulanic acid, ticarcillin, cefoxitin, cefotaxime, aztreonam, imipenem, ertapenem, gentamicin, amikacin, ciprofloxacin, colistin, trimethoprim/sulfamethoxazole and fosfomycin, was performed using the disk diffusion method on Mueller-Hinton agar. ESBL-production was screened by the double-disk synergy test and confirmed by molecular characterization using PCR (polymerase chain reaction) amplification and sequencing of ESBL encoding genes. Clonality of the avian and human strains was performed using the Multi Locus Sequencing Typing method (MLST). Forty-five isolated avian Salmonella strains and 37 human collected ones were studied. Five S. enterica serotypes were found in avian isolates (mainly Kentucky) and 9 from human ones (essentially Infantis). 51.11% and 26.6% of the avian isolates were resistant to ciprofloxacin and cefotaxime, respectively, whereas human isolates were less resistant to these antibiotics (13.5% to ciprofloxacin and 16.2% to cefotaxime). Eighteen (12 avian and 6 human) strains were found to produce ESBLs, which were identified as bla CTX-M-1 (n = 12), bla CTX-M-15 (n = 5) and bla TEM group (n = 8). Interestingly, seven of the ESBL-producing strains (5 avian and 2 human) were of the same ST (ST15) and

  1. Complete genome sequence of Lactobacillus plantarum LZ95, a potential probiotic strain producing bacteriocins and B-group vitamin riboflavin.

    Science.gov (United States)

    Li, Ping; Gu, Qing

    2016-07-10

    Lactobacillus plantarum LZ95 is a potential probiotic isolated from newborn infant fecal and it is identified to produce riboflavin with great antimicrobial activity. The complete genome sequence of this strain was reported in the present study. The genome contains a 3,261,418-bp chromosome and two plasmids. Genes, related to the biosynthesis of bacteriocins and riboflavin, were identified. This work will facilitate to reveal the biosynthetic mechanism of bacteriocins and B-group vitamins in lactic acid bacteria and provide evidence for its potential application in food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Characterization of a Bacteriocin-Like Substance Produced by a Vaginal Lactobacillus salivarius Strain

    Science.gov (United States)

    Ocaña, Virginia S.; Pesce de Ruiz Holgado, Aída A.; Nader-Macías, María Elena

    1999-01-01

    A novel bacteriocin-like substance produced by vaginal Lactobacillus salivarius subsp. salivarius CRL 1328 with activity against Enterococcus faecalis, Enterococcus faecium, and Neisseria gonorrhoeae was characterized. The highest level of production of this heat-resistant peptide or protein occurred during the late exponential phase. Its mode of action was shown to be bactericidal. L. salivarius subsp. salivarius CRL 1328 could be used for the design of a probiotic to prevent urogenital infections. PMID:10584033

  3. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

    OpenAIRE

    Savino, Francesco; Cordisco, Lisa; Tarasco, Valentina; Locatelli, Emanuela; Di Gioia, Diana; Oggero, Roberto; Matteuzzi, Diego

    2011-01-01

    Abstract Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lac...

  4. Structural analysis and characterization of dextran produced by wild and mutant strains of Leuconostoc mesenteroides.

    Science.gov (United States)

    Siddiqui, Nadir Naveed; Aman, Afsheen; Silipo, Alba; Qader, Shah Ali Ul; Molinaro, Antonio

    2014-01-01

    An exopolysaccharide known as dextran was produced by Leuconostoc mesenteroides KIBGE-IB22 (wild) and L. mesenteroides KIBGE-IB22M20 (mutant). The structure was characterized using FTIR, (1)H NMR, (13)C NMR and 2D NMR spectroscopic techniques, whereas surface morphology was analyzed using SEM. A clear difference in the spectral chemical shift patterns was observed in both samples. All the spectral data indicated that the exopolysaccharide produced by KIBGE-IB22 is a mixture of two biopolymers. One was dextran in α-(1 → 6) configuration with a small proportion of α-(1 → 3) branching and the other was levan containing β-(2 → 6) fructan fructofuranosyl linkages. However, remarkably the mutant only produced dextran without any concomitant production of levan. Study suggested that the property of KIBGE-IB22M20, regarding improved production of high molecular weight dextran in a shorter period of fermentation time without any contamination of other exopolysaccharide, could be employed to make the downstream process more feasible and cost effective on large scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Improved production, purification, and characterization of biosurfactants produced by Serratia marcescens SM3 and its isogenic SMRG-5 strain.

    Science.gov (United States)

    Rosas-Galván, Nashbly Sarela; Martínez-Morales, Fernando; Marquina-Bahena, Silvia; Tinoco-Valencia, Raunel; Serrano-Carreón, Leobardo; Bertrand, Brandt; León-Rodríguez, Renato; Guzmán-Aparicio, Josefina; Alvaréz-Berber, Laura; Trejo-Hernández, María R

    2018-02-19

    In this study, the biosurfactants (Bs) production of two Serratia marcescens strains (SM3 and its isogenic SMRG-5 strain) was improved and the tenso-active agents were purified and characterized. A 2 3 factorial design was used to evaluate the effect of nitrogen and carbon sources on the surface tension (ST) reduction and emulsion index (EI 24 ) of the produced Bs. Optimum Bs production by SM3 was achieved at high concentrations of carbon and nitrogen, reducing ST to 26.5 ± 0.28 dynes/cm, with an EI 24 of 79.9 ± 0.2%. Meanwhile, the best results for SMRG-5 were obtained at low concentrations, reducing the ST to 25.2 ± 0.2 dynes/cm, with an EI 24 of 89.7 ± 0.28%. The optimal conditions for Bs production were scaled up in a 2-L reactor, yielding 4.8 and 5.2 g/L for SM3 and SMRG-5, respectively. Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed the presence of two different lipopeptides (hidrofobic fractions: octadecanoic and hexadecanoic acid for SM3 and SMRG5, respectively). Both strains were capable of benzo [a] pyrene removal (59% after 72 H of culture). © 2018 International Union of Biochemistry and Molecular Biology, Inc.

  6. Selection and protein sds-page identification of a new high-producing polysaccharide strain of Spirulina platensis

    International Nuclear Information System (INIS)

    Wang Zhiping; Liu Yanhui

    2004-01-01

    The relationship between anti-radiation capacity and polysaccharide contents of ten Spirulina platensis strains were studied. The results showed that the correlation coefficient between 60 Co γ-ray half-lethal dose (LD 50 ) and polysaccharide contents of the 10 strains was 0.9873. After the single cells or spheroplasts of Sp-08 were treated by 0.6%EMS and 2.4 kGy 60 Co γ-ray irradiation, four morphological mutant named Sp-08A, Sp-08B, Sp-08C and Sp-08D, which could endure about 7.0 kGy γ-ray irradiation, were obtained. The polysaccharide contents of Sp-08A, Sp-08B, Sp-08C and Sp-08D, were 32.8%, 17.3%, 3.4% and 42.3% higher than that of their parent Sp-08, respectively. The results of protein SDS-PAGE analysis showed that the heredity of Sp-08A, Sp-08C and Sp-08D were mutated. Therefore, Sp-08A was a perfect high-producing polysaccharide strain with excellent characteristics of morphology and growth. Now, Sp-08A is applied in mass cultivation and industrialization. (authors)

  7. The importance of Bordetella pertussis strains which do not produce virulence factors in the epidemiology of pertussis

    Directory of Open Access Journals (Sweden)

    Maciej Polak

    2017-05-01

    Full Text Available Bordetella pertussis strains, which have lost the ability to produce antigens, such as pertactin - Prn, pertussis toxin - Ptx, filamentous haemagglutinin - FHA, fimbriae type 2 and 3 - Fim 2 and 3, tracheal colonization factor - TcfA, have recently been isolated in countries with a high vaccination coverage. The emergence of such isolates might have resulted from B. pertussis natural evolution course or adaptive mechanisms, allowing increased circulation of the pathogen in vaccinated populations. So far, the majority of described mutants were deficient in the Prn production. Prn deficient isolates were found in countries which use acellular pertussis vaccines (aP in routine immunization programmes. The increase of frequency of Prn¯ strains isolation was correlated with the period of routine vaccination with aP vaccines. In most countries, the spread of these isolates has resulted from independent mutations rather than from the expansion of a single clone. Prn¯ isolates were collected from patients showing typical clinical symptoms of pertussis found for Prn+ strains. Results of in vitro and in vivo studies have shown that Prn¯, Ptx¯ and FHA¯ isolates retain cytotoxic properties, and besides Ptx¯ isolates, were lethal in intranasally infected mice. Further explanation of the impact of antigen deficiencies on virulence and transmission of B. pertussis in the context of the continuous increase of pertussis incidence is necessary to develop a new, optimized strategy of pertussis prevention.

  8. High Frequency and Diversity of Antimicrobial Activities Produced by Nasal Staphylococcus Strains against Bacterial Competitors.

    Directory of Open Access Journals (Sweden)

    Daniela Janek

    2016-08-01

    Full Text Available The human nasal microbiota is highly variable and dynamic often enclosing major pathogens such as Staphylococcus aureus. The potential roles of bacteriocins or other mechanisms allowing certain bacterial clones to prevail in this nutrient-poor habitat have hardly been studied. Of 89 nasal Staphylococcus isolates, unexpectedly, the vast majority (84% was found to produce antimicrobial substances in particular under habitat-specific stress conditions, such as iron limitation or exposure to hydrogen peroxide. Activity spectra were generally narrow but highly variable with activities against certain nasal members of the Actinobacteria, Proteobacteria, Firmicutes, or several groups of bacteria. Staphylococcus species and many other Firmicutes were insusceptible to most of the compounds. A representative bacteriocin was identified as a nukacin-related peptide whose inactivation reduced the capacity of the producer Staphylococcus epidermidis IVK45 to limit growth of other nasal bacteria. Of note, the bacteriocin genes were found on mobile genetic elements exhibiting signs of extensive horizontal gene transfer and rearrangements. Thus, continuously evolving bacteriocins appear to govern bacterial competition in the human nose and specific bacteriocins may become important agents for eradication of notorious opportunistic pathogens from human microbiota.

  9. NEW STRAIN PRODUCERS OF BIOBUTANOL. III. METHODS OF INCREASED BUTANOL ACCUMULATION FROM BIOMASS OF SWITCHGRASS Panicum virgatum L.

    Directory of Open Access Journals (Sweden)

    Tigunova O. O.

    2015-08-01

    Full Text Available The aim of this work was to enlarge accumulation of butanol from switchgrass Panicum virgatum L. biomass using strains-producers obtained from grounds and silts of Kyiv lakes. The objects of the study were strains of C. acetobutylicum ІМВ B-7407 (IFBG C6H, Clostridium acetobutylicum IFBG C6H 5М and Clostridium tyrobutyricum IFBG C4B from the "Collections of microbial strains and lines of plants for food and agricultural biotechnology" of the Public Institution "Institute of Food Biotechnology and Genomics" of the National Academy of Sciences of Ukraine. Gas chromatography was used to determine the alcohol concentration at the stage of solvent synthesis. To determine the effect of butanol precursors during cultivation, butyric, lactic and acetic acids were used. Optimization of processing parameters, which was based on the needs of cultures, allowed us to increase the yield by 20 and 50% for the initial and mutant strain respectively. Using synthetic precursors (such as lactic, butyric and acetic acid during cultivation increased total concentration of butanol by 1.7 times. To optimize the process, a study was carried out using acetone- butyl grains. Using of acetone-butyl grains in concentrations up to 60% does not affect the synthesis of butanol by C. acetobutylicum IFBG C6H 5M. Increasing the concentration of grains led to decrease in accumulation of butanol. Almost double increase in accumulation of the target product (butanol was achieved using two-stage fermentation and/or precursors of synthesis. It was shown the possibility of using acetone-butyl grains in fermentation. As a result the mass fraction of the waste was reduced.

  10. Purification and genetic characterisation of the novel bacteriocin LS2 produced by the human oral strain Lactobacillus salivarius BGHO1.

    Science.gov (United States)

    Busarcevic, Milos; Dalgalarrondo, Michèle

    2012-08-01

    The aim of this study was to investigate the antimicrobial potential of Lactobacillus salivarius BGHO1, a human oral strain with probiotic characteristics and a broad inhibitory spectrum both against Gram-positive and Gram-negative pathogens. Here we present the bacteriocin LS2, an extremely pH- and heat-stable peptide with antilisterial activity. LS2 is a novel member of the class IId bacteriocins, unique among all currently characterised bacteriocins. It is somewhat similar to putative bacteriocins from several oral streptococci, including the cariogenic Streptococcus mutans. LS2 is a 41-amino-acid, highly hydrophobic cationic peptide of 4115.1Da that is sensitive to proteolytic enzymes. LS2 was purified from cells of strain BGHO1 by solvent extraction and reverse-phase chromatography. Mass spectrometry was used to determine the molecular mass of the purified peptide. N-terminal amino acid sequencing enabled identification of the LS2 structural gene bacls2 by a reverse genetics approach. Downstream of the bacls2 gene, two bacteriocin-like genes were found, named blp1a and blp1b, and one putative bacteriocin immunity gene named bimlp. We also present the identification of the 242-kb megaplasmid pMPHO1 by pulsed-field gel electrophoresis, which harbours the genes bacls2, blp1a, blp1b and bimlp. Two peptides with antimicrobial activity, whose approximate sizes corresponded to those of blp1a and blp1b, were identified only after culturing strain BGHO1 in a chemically defined medium. This study demonstrated the capacity of Lactobacillus salivarius BGHO1 to produce multiple bacteriocins and further established this strain as a promising probiotic candidate. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  11. Morphology and physiology of an alpha Amylase producing strain of Aspergillus oryzae during batch cultivations

    DEFF Research Database (Denmark)

    Carlsen, Morten; Spohr, Anders Bendsen; Nielsen, Jens Bredal

    1996-01-01

    , whereas the alpha-amylase production has a sharper maximum at about pH 6. During batch cultivation with pellets the growth is described well by the cube-root law when pellet fragmentation can be neglected. The kinetic parameter k in the cube-root law is derived from the growth kinetics with no mass......, suggesting that ethanol is produced in the oxygen limited part of the biomass. A constitutive, low alpha-amylase production was observed at high glucose concentration. The specific alpha-amylase production was significantly higher for filamentous growth than for pellets and oxygen appears to be necessary...... for production of alpha-amylase. (C) 1996 John Wiley & Sons, Inc....

  12. Characterization of thermostable cellulase produced by Bacillus strains isolated from solid waste of carrageenan

    Science.gov (United States)

    Listyaningrum, N. P.; Sutrisno, A.; Wardani, A. K.

    2018-03-01

    Cellulase-producing bacteria was isolated from solid waste of carrageenan and identified as Bacillus licheniformis C55 by 16S rRNA sequencing. The optimum condition for cellulase production was obtained at pH and temperature of 8.0 and 50°C, respectively in a medium containing glucose as carbon source and 1.0% carboxymethyl cellulose (CMC) to stimulate the cellulase production. Most remarkably, the enzyme retained its relative activity over 50% after incubation at 50°C for 90 minutes. Substrate specificity suggested that the enzyme is an endoglucanase. The molecular mass of Bacillus licheniformis C55 crude cellulase was found about 18 kDa by SDS-PAGE analysis. This thermostable enzyme would facilitate development of more efficient and cost-effective forms of the process to convert lignocellulosic biomass into high-value products.

  13. Draft Genome Sequence of Lactobacillus delbrueckii subsp. bulgaricus CRL871, a Folate-Producing Strain Isolated from a Northwestern Argentinian Yogurt.

    Science.gov (United States)

    Laiño, Jonathan Emiliano; Hebert, Elvira María; Savoy de Giori, Graciela; LeBlanc, Jean Guy

    2015-06-25

    Lactobacillus delbrueckii subsp. bulgaricus CRL871 is the first strain of L. delbrueckii subsp. bulgaricus reported as a folate-producing strain. We report the draft genome sequence of L. delbrueckii subsp. bulgaricus CRL871 (2,063,981 bp, G+C content of 49.1%). This strain is of great biotechnological importance to the dairy industry because it constitutes an alternative to folic acid fortification. Copyright © 2015 Laiño et al.

  14. Different nitrogen sources change the transcriptome of welan gum-producing strain Sphingomonas sp. ATCC 31555.

    Science.gov (United States)

    Xu, Xiaopeng; Nie, Zuoming; Zheng, Zhiyong; Zhu, Li; Zhang, Hongtao; Zhan, Xiaobei

    2017-09-01

    To reveal effects of different nitrogen sources on the expressions and functions of genes in Sphingomonas sp. ATCC 31555, it was cultivated in medium containing inorganic nitrogen (IN), organic nitrogen (ON), or inorganic-organic combined nitrogen (CN). Welan gum production and bacterial biomass were determined, and RNA sequencing (RNA-seq) was performed. Differentially expressed genes (DEGs) between the different ATCC 31555 groups were identified, and their functions were analyzed. Welan gum production and bacterial biomass were significantly higher in the ON and CN groups compared with those in the IN group. RNA-seq produced 660 unigenes, among which 488, 731, and 844 DEGs were identified between the IN vs. ON, IN vs. CN, and ON vs. CN groups, respectively. All the DEGs were related significantly to metabolic process and signal transduction. DEGs between the IN vs. CN and ON vs. CN groups were potentially associated with bacterial chemotaxis. Real-time PCR confirmed the expressions of selected DEGs. Organic nitrogen led to higher bacterial biomass and welan gum production than inorganic nitrogen, which might reflect differences in gene expression associated with metabolic process, signal transduction, and bacterial chemotaxis induced by different nitrogen sources.

  15. Intra-operative ultrasound hand-held strain imaging for the visualization of ablations produced in the liver with a toroidal HIFU transducer: first in vivo results

    Energy Technology Data Exchange (ETDEWEB)

    Chenot, J; Melodelima, D; N' Djin, W A; Souchon, Remi; Rivoire, M; Chapelon, J Y, E-mail: jeremy.chenot@inserm.f [Inserm, U556, Lyon, F-69003 (France)

    2010-06-07

    The use of hand-held ultrasound strain imaging for the intra-operative real-time visualization of HIFU (high-intensity focused ultrasound) ablations produced in the liver by a toroidal transducer was investigated. A linear 12 MHz ultrasound imaging probe was used to obtain radiofrequency signals. Using a fast cross-correlation algorithm, strain images were calculated and displayed at 60 frames s{sup -1}, allowing the use of hand-held strain imaging intra-operatively. Fourteen HIFU lesions were produced in four pigs. Intra-operative strain imaging of HIFU ablations in the liver was feasible owing to the high frame rate. The correlation between dimensions measured on gross pathology and dimensions measured on B-mode images and on strain images were R = 0.72 and R = 0.94 respectively. The contrast between ablated and non-ablated tissue was significantly higher (p < 0.05) in the strain images (22 dB) than in the B-mode images (9 dB). Strain images allowed equivalent or improved definition of ablated regions when compared with B-mode images. Real-time intra-operative hand-held strain imaging seems to be a promising complement to conventional B-mode imaging for the guidance of HIFU ablations produced in the liver during an open procedure. These results support that hand-held strain imaging outperforms conventional B-mode ultrasound and could potentially be used for the assessment of thermal therapies.

  16. Bacillus amyloliquefaciens TSBSO 3.8, a biosurfactant-producing strain with biotechnological potential for microbial enhanced oil recovery.

    Science.gov (United States)

    Alvarez, Vanessa Marques; Jurelevicius, Diogo; Marques, Joana Montezano; de Souza, Pamella Macedo; de Araújo, Livia Vieira; Barros, Thalita Gonçalves; de Souza, Rodrigo Octavio Mendonça Alves; Freire, Denise Maria Guimarães; Seldin, Lucy

    2015-12-01

    A screening for biosurfactant-producing bacteria was conducted with 217 strains that were isolated from environmental samples contaminated with crude oil and/or petroleum derivatives. Although 19 promising biosurfactant producers were detected, strain TSBSO 3.8, which was identified by molecular methods as Bacillus amyloliquefaciens, drew attention for its production of a high-activity compound that presented an emulsification activity of 63% and considerably decreased surface (28.5 mN/m) and interfacial (11.4 mN/m) tensions in Trypticase Soy Broth culture medium. TSBSO 3.8 growth and biosurfactant production were tested under different physical and chemical conditions to evaluate its biotechnological potential. Biosurfactant production occurred between 0.5% and 7% NaCl, at pH values varying from 6 to 9 and temperatures ranging from 28 to 50 °C. Moreover, biosurfactant properties remained the same after autoclaving at 121 °C for 15 min. The biosurfactant was also successful in a test to simulate microbial enhanced oil recovery (MEOR). Mass spectrometry analysis showed that the surface active compound was a surfactin, known as a powerful biosurfactant that is commonly produced by Bacillus species. The production of a high-efficiency biosurfactant, under some physical and chemical conditions that resemble those experienced in an oil production reservoir, such as high salinities and temperatures, makes TSBSO 3.8 an excellent candidate and creates good expectations for its application in MEOR. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Evolution of a recombinant (gucoamylase-producing) strain of Fusarium venenatum A3/5 in chemostat culture.

    Science.gov (United States)

    Wiebe, M G; Robson, G D; Shuster, J; Trinci, A P

    2001-04-20

    Fusarium venenatum JeRS 325 is a transformant of strain A3/5 which produces Aspergillus niger glucoamylase (GAM) under the control of a Fusarium oxysporum trypsin-like protease promoter. The evolution of JeRS 325 was studied in glucose-limited chemostat cultures grown on NaNO3 or (NH4)2SO4 as the nitrogen source. Thirteen mutants which were more highly branched and four mutants which were more sparsely branched than the parental strain were isolated from the NaNO3 chemostat. The highly branched mutants detected in this chemostat did not displace the sparsely branched population. The mutants isolated from the NaNO3 chemostat complemented representative strains previously isolated from glucose-limited chemostat cultures of F. venenatum A3/5 grown on (NH4)2SO4, but showed little complementation between themselves. By contrast, a highly branched mutant isolated from the (NH4)2SO4 chemostat culture displaced the sparsely branched mycelial population. None of the mutants isolated from the NaNO3 or (NH4)2SO4 chemostats produced as much GAM as JeRS 325. Southern blot analysis showed that all except one mutant had lost copies of both the glucoamylase and the acetamidase (the selectable marker) genes. However, specific GAM production was not necessarily correlated with the extent of glaA gene loss observed. Further, 10 of the mutants had lost the ability to grow on acetamide as the sole nitrogen source, although they retained copies of the amdS gene. In competition studies, mutants which could not utilize acetamide displaced mutants which could. The presence of foreign DNA in JeRS 325 resulted in a reduced specific growth rate (compared to A3/5), but the presence of the foreign DNA did not prevent the evolution of the strain or the isolation of mutants which had improved growth rates. Copyright 2001 John Wiley & Sons, Inc.

  18. Activities of beta-lactam antibiotics against Escherichia coli strains producing extended-spectrum beta-lactamases.

    Science.gov (United States)

    Jacoby, G A; Carreras, I

    1990-01-01

    Seven extended-spectrum beta-lactamases related to TEM and four enzymes derived from SHV-1 were transferred to a common Escherichia coli host so that the activity of a variety of beta-lactams could be tested in a uniform genetic environment. For most derivatives, penicillinase activity was 10% or less than that of strains making TEM-1, TEM-2, or SHV-1 beta-lactamase, suggesting that reduced catalytic efficiency accompanied the broader substrate spectrum. Despite this deficit, resistance to aztreonam, carumonam, cefdinir, cefepime, cefixime, cefmenoxime, cefotaxime, cefotiam, cefpirome, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefuroxime, and E1040 was enhanced. For strains producing TEM-type enzymes, however, MICs of carumonam, cefepime, cefmenoxime, cefotiam, cefpirome, and ceftibuten were 8 micrograms/ml or less. Susceptibilities of cefmetazole, cefotetan, cefoxitin, flomoxef, imipenem, meropenem, moxalactam, temocillin, FCE 22101, and Sch 34343 were unaffected. FCE 22101, imipenem, meropenem, and Sch 34343 were inhibitory for all strains at 1 microgram/ml or less. In E. coli an OmpF- porin mutation in combination with an extended-spectrum beta-lactamase enhanced resistance to many of these agents, but generally by only fourfold. Hyperproduction of chromosomal AmpC beta-lactamase increased resistance to 7-alpha-methoxy beta-lactams but not that to temocillin. When tested at 8 micrograms/ml, clavulanate was more potent than sulbactam or tazobactam in overcoming resistance to ampicillin, while cefoperazone-sulbactam was more active than ticarcillin-clavulanate or piperacillin-tazobactam, especially against TEM-type extended-spectrum beta-lactamases. PMID:2193623

  19. Comparative Genomics of Acetobacterpasteurianus Ab3, an Acetic Acid Producing Strain Isolated from Chinese Traditional Rice Vinegar Meiguichu.

    Science.gov (United States)

    Xia, Kai; Li, Yudong; Sun, Jing; Liang, Xinle

    2016-01-01

    Acetobacter pasteurianus, an acetic acid resistant bacterium belonging to alpha-proteobacteria, has been widely used to produce vinegar in the food industry. To understand the mechanism of its high tolerance to acetic acid and robust ability of oxidizing ethanol to acetic acid (> 12%, w/v), we described the 3.1 Mb complete genome sequence (including 0.28 M plasmid sequence) with a G+C content of 52.4% of A. pasteurianus Ab3, which was isolated from the traditional Chinese rice vinegar (Meiguichu) fermentation process. Automatic annotation of the complete genome revealed 2,786 protein-coding genes and 73 RNA genes. The comparative genome analysis among A. pasteurianus strains revealed that A. pasteurianus Ab3 possesses many unique genes potentially involved in acetic acid resistance mechanisms. In particular, two-component systems or toxin-antitoxin systems may be the signal pathway and modulatory network in A. pasteurianus to cope with acid stress. In addition, the large numbers of unique transport systems may also be related to its acid resistance capacity and cell fitness. Our results provide new clues to understanding the underlying mechanisms of acetic acid resistance in Acetobacter species and guiding industrial strain breeding for vinegar fermentation processes.

  20. Isolation and functional characterization of a biosurfactant produced by a new and promising strain of Oleomonas sagaranensis AT18.

    Science.gov (United States)

    Saimmai, Atipan; Rukadee, Onkamon; Onlamool, Theerawat; Sobhon, Vorasan; Maneerat, Suppasil

    2012-10-01

    Biosurfactant-producing bacteria were isolated from mangrove sediment in southern Thailand. Isolates were screened for biosurfactant production by using the surface tension test. The highest reduction of surface tension was achieved with a bacterial strain which was identified by 16S rRNA gene sequencing as Oleomonas sagaranensis AT18. It has also been investigated using different carbon and nitrogen sources. It showed that the strain was able to grow and reduce the surface tension of the culture supernatant to 25 mN/m. In all 5.30 g of biosurfactant yield was obtained after 54 h of cultivation by using molasses and NaNO₃ as carbon and nitrogen sources, respectively. The biosurfactant recovery by chloroform:methanol extraction showed a small critical micelle concentration value (8 mg/l), thermal and pH stability with respect to surface tension reduction. It also showed emulsification activity and a high level of salt concentration. The biosurfactant obtained was confirmed as a glycolipid by using a biochemical test, FT-IR and mass spectra. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance PAHs solubility.

  1. Mesophilic Lactic Acid Bacteria Diversity Encountered in Brazilian Farms Producing Milk with Particular Interest in Lactococcus lactis Strains.

    Science.gov (United States)

    Luiz, L M P; Chuat, V; Madec, M N; Araújo, E A; de Carvalho, A F; Valence, F

    2016-10-01

    The milk produced in regions with different traditions in Brazil is used for artisanal product production, which is characterized by different sensorial characteristics. This study aimed to identify the bacterial ecosystem of farms located in a traditional dairy region in the state of Minas Gerais and to characterize Lactococcus lactis strains, the species of interest in this study, using a multilocus sequence typing (MLST) protocol and pulsed-field gel electrophoresis (PFGE) technique. Samples were collected from raw milk and dairy environment from six farms. A total of 50 isolates were analyzed using 16S rRNA sequencing and species-specific PCR. Five genera were identified: Lactobacillus, Leuconostoc, Lactococcus, Enterococcus, and Staphylococcus, from ten different species. MLST (with six housekeeping genes) and PFGE (with SmaI endonuclease) were used for the characterization of 20 isolates of Lactococcus lactis from a dairy collection in this study. Both methods revealed a high clonal diversity of strains with a higher discriminatory level for PFGE (15 pulsotypes), compared to MLST (12 ST). This study contributes to the preservation of the Brazilian dairy heritage and provides insights into a part of the LAB population found in raw milk and dairy environment.

  2. CpG oligodeoxynucleotides are a potent adjuvant for an inactivated polio vaccine produced from Sabin strains of poliovirus.

    Science.gov (United States)

    Yang, Chunting; Shi, Huiying; Zhou, Jun; Liang, Yanwen; Xu, Honglin

    2009-11-05

    Poliovirus transmission is controlled globally through world-wide use of a live attenuated oral polio vaccine (OPV). However, the imminence of global poliovirus eradication calls for a switch to the inactivated polio vaccine (IPV). Given the limited manufacturing capacity and high cost of IPV, this switch is unlikely in most developing and undeveloped countries. Adjuvantation is an effective strategy for antigen sparing. In this study, we evaluated the adjuvanticity of CpG oligodeoxynucleotides (CpG-ODN) for an experimental IPV produced from Sabin strains of poliovirus. Our results showed that CpG-ODN, alone or in combination with alum, can significantly enhance both the humoral and cellular immune responses to IPV in mice, and, consequently, the antigen dose could be reduced substantially. Therefore, our study suggests that the global use of IPV could be facilitated by using CpG-ODN or other feasible adjuvants.

  3. Optimization of biosynthesis conditions and catalitic behavior evaluation of cellulase-free xylanase produced by a new Streptomyces sp. strain

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    GABRIELA BAHRIM

    2011-07-01

    Full Text Available Cellulase-free xylanase by Streptomyces sp.P12-137 was obtained bycultivation on the wheat bran as the sole carbon source. The effect of carbon and nitrogen sources and a ratio of them on the cellulase-free xylanase production was investigated. The new isolate Streptomyces sp. strain was able to grow in submerged system and to produce an increased level of xylanase. Wheat bran induced xylanase biosynthesis yield at a high level (9.27 UA/ml. For economical reasons cultivation was achieved on a cheap fermentative medium represented by agro-industrial wastes. The optima of the pH and temperature of the crude xylanase activity were 5.5 and 70°C,respectively.

  4. Mechanism of Excretion of a Bacterial Proteinase: Demonstration of Two Proteolytic Enzymes Produced by a Sarcina Strain (Coccus P)

    Energy Technology Data Exchange (ETDEWEB)

    SARNER, NITZA Z; BISSELL, MINA J; GIROLAMO, MARIO Di; GORINI, LUIGI

    1970-06-29

    A Sarcina strain (Coccus P) produces two proteolytic enzymes. One is found only extracellularly, is far more prevalent, and is actively excreted during exponential growth. It is the enzyme responsible for the known strong proteolytic activity of the cultures of this strain. A second protease is, however, produced which remains associated with the intact cells but is released by the protoplasts. The two enzymes appear unrelated in their derivation. Calcium ions play an essential role in preventing autodigestion of the excreted enzyme. Bacterial proteins are found outside the cell boundary as a consequence either of passive processes such as leakage or lysis or of active excretion. Under conditions in which leakage and lysis do not occur, as during exponential growth, the cell boundary is a barrier causing a complete separation of the bulk of the intracellular proteins from the one or very few extracellular proteins, with no trace of either type being detectable on the wrong side of the boundary. Since in bacteria there is no evidence of protein being produced other than internally, the separation into intraand extracellular proteins should occur after peptide chain formation. The question arises as to whether the structure of the cell boundary or that of the excreted proteins themselves determines this separation. Coccus P, a Sarcina closely related to Micrococcus lysodeikticus (3), produces an extracellular proteinase during the exponential phase of growth so that the process appears to be active excretion. The organism grows exponentially in a defined synthetic medium (12) to relatively high cell density (10{sup 9} cells/ml); therefore the mechanism of excretion can be studied over an extended period of time without the difficulties of changing growth rates. Coagulation of reconstituted skim milk provides a simple and sensitive assay for enzyme activity (I 1). The extracellular proteinase has also been purified and partially characterized (6-8). It has been shown

  5. Characteristics of Shigatoxin-Producing Escherichia coli Strains Isolated during 2010–2014 from Human Infections in Switzerland

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    Lisa Fierz

    2017-08-01

    Full Text Available Objectives: The aim of this study was to characterize a collection of 95 Shigatoxin-producing E.coli (STEC isolated from human patients in Switzerland during 2010–2014.Methods: We performed O and H serotyping and molecular subtyping.Results: The five most common serogroups were O157, O145, O26, O103, and O146. Of the 95 strains, 35 (36.8% carried stx1 genes only, 43 strains (45.2% carried stx2 and 17 (17.9% harbored combinations of stx1 and stx2 genes. Stx1a (42 strains and stx2a (32 strains were the most frequently detected stx subtypes. Genes for intimin (eae, hemolysin (hly, iron-regulated adhesion (iha, and the subtilase cytotoxin subtypes subAB1, subAB2-1, subAB2-2, or subAB2-3 were detected in 70.5, 83.2, 74.7, and 20% of the strains, respectively. Multilocus sequence typing assigned the majority (58.9% of the isolates to five different clonal complexes (CC, 11, 32, 29, 20, and 165, respectively. CC11 included all O157:[H7] and O55:[H7] isolates. CC32 comprised O145:[H28] isolates, and O145:[H25] belonged to sequence type (ST 342. CC29 contained isolates of the O26:[H11], O111:[H8] and O118:[Hnt] serogroups, and CC20 encompassed isolates of O51:H49/[Hnt] and O103:[H2]. CC165 included isolates typed O80:[H2]-ST301, all harboring stx2d, eae-ξ, hly, and 66.7% additionally harboring iha. All O80:[H2]-ST301 strains harbored at least 7 genes carried by pS88, a plasmid associated with extraintestinal virulence. Compared to data from Switzerland from the years 2000–2009, an increase of the proportion of non-O157 STEC infections was observed as well as an increase of infections due to STEC O146. By contrast, the prevalence of the highly virulent German clone STEC O26:[H11]-ST29 decreased from 11.3% during 2000–2009 to 1.1% for the time span 2010–2014. The detection of O80:[H2]-ST301 harboring stx2d, eae-ξ, hly, iha, and pS88 related genes suggests an ongoing emergence in Switzerland of an unusual, highly pathogenic STEC serotype

  6. The Effect of Phenazine-1-Carboxylic Acid on Mycelial Growth of Botrytis cinerea Produced by Pseudomonas aeruginosa LV Strain

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    Ane S. Simionato

    2017-06-01

    Full Text Available One of the most important postharvest plant pathogens that affect strawberries, grapes and tomatoes is Botrytis cinerea, known as gray mold. The fungus remains in latent form until spore germination conditions are good, making infection control difficult, causing great losses in the whole production chain. This study aimed to purify and identify phenazine-1-carboxylic acid (PCA produced by the Pseudomonas aeruginosa LV strain and to determine its antifungal activity against B. cinerea. The compounds produced were extracted with dichloromethane and passed through a chromatographic process. The purity level of PCA was determined by reversed-phase high-performance liquid chromatography semi-preparative. The structure of PCA was confirmed by nuclear magnetic resonance and electrospray ionization mass spectrometry. Antifungal activity was determined by the dry paper disk and minimum inhibitory concentration (MIC methods and identified by scanning electron microscopy and confocal microscopy. The results showed that PCA inhibited mycelial growth, where MIC was 25 μg mL-1. Microscopic analysis revealed a reduction in exopolysaccharide (EPS formation, showing distorted and damaged hyphae of B. cinerea. The results suggested that PCA has a high potential in the control of B. cinerea and inhibition of EPS (important virulence factor. This natural compound is a potential alternative to postharvest control of gray mold disease.

  7. Characterization of Extracellular Penicilin G Acylase Produced by A New Local Strain of Bacillus subtilis BAC4

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    SUPARTONO

    2008-06-01

    Full Text Available Penicillin G acylase (PGA which catalyses penicillin G hydrolysis reaction is a key enzyme for the industrial production of penicilin G derivatives used in therapeutics. A new local strain of Bacillus subtilis BAC4 was found capable of producing extracellular PGA. However, characteristics of this extracellular PGA are not known. The goal of this research was to characterize the extracellular PGA produced by B. subtilis BAC4. Enzyme production was carried out by batch fermentation, followed by enzyme purification and characterization of the PGA. The PGA activity was determined by the Kornfeld method, with optimal activity for hydrolysing penicillin G observed at 43 °C and pH 8.5. The activation energy of penicillin G hydrolysis by the PGA of B. subtilis BAC4 was determined as 4.9 kcal.mol−1 and Vmax and Km values were found to be 0.7 μmole.min−1.mg−1 and 3.5 mM respectively. PGA catalytic activity was competitively inhibited by phenylacetic acid with an inhibition constant, Ki(PAA, of 347.2 mM. It was concluded that the extracellular PGA of B. subtilis BAC4 can hydrolyse penicillin G efficiently.

  8. Characterization of Extracellular Penicilin G Acylase Produced by A New Local Strain of Bacillus subtilis BAC4

    Directory of Open Access Journals (Sweden)

    SUPARTONO

    2008-06-01

    Full Text Available Penicillin G acylase (PGA which catalyses penicillin G hydrolysis reaction is a key enzyme for the industrial production of penicilin G derivatives used in therapeutics. A new local strain of Bacillus subtilis BAC4 was found capable of producing extracellular PGA. However, characteristics of this extracellular PGA are not known. The goal of this research was to characterize the extracellular PGA produced by B. subtilis BAC4. Enzyme production was carried out by batch fermentation, followed by enzyme purification and characterization of the PGA. The PGA activity was determined by the Kornfeld method, with optimal activity for hydrolysing penicillin G observed at 43 oC and pH 8.5. The activation energy of penicillin G hydrolysis by the PGA of B. subtilis BAC4 was determined as 4.9 kcal.mol-1 and Vmax and Km values were found to be 0.7 µmole.min-1.mg-1 and 3.5 mM respectively. PGA catalytic activity was competitively inhibited by phenylacetic acid with an inhibition constant, Ki(PAA, of 347.2 mM. It was concluded that the extracellular PGA of B. subtilis BAC4 can hydrolyse penicillin G efficiently.

  9. Isolation and identification of biosurfactant-producing strains from the genus Pseudomonas aeruginosa and antibacterial effects of biosurfactant production in vitro

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    Salman Ahmady-Asbchin

    2013-01-01

    Full Text Available Introduction: Biosurfactants are amphiphilic biological compounds produced extracellularly or as part of the cell membranes by a variety of microorganisms. Because of their use in various industries, they are of a particular importance. The aim of this study was to identify a strain of bacteria of the genus Pseudomonas aeruginosa biosurfactant producers. Materials and methods: In this study, different samples of oil, water and soil contaminated with oil were prepared. Hemolytic activity, emulsification activity and measurement of surface tension were used and selected strains were identified by biochemical tests. The nature and effect of antibacterial biosurfactant was evaluated for strain selection.Results: In this study, eighty eight bacterial strains were isolated. Twenty four strains were isolated from the isolated strains with hemolytic activity. Among which, 14 strains have emulsification activity more than 70% and at last four strains reached surface tension to be less than 40 mN/m. Selected strain based on biochemical tests was recognized as a Pseudomonas aeruginosa. The nature of biosurfactant was determined by TLC, and proved to be of glycolipid kind. Therefore, the produced biosurfactant of the selected strain had antibacterial activity against six bacterial infectious. Sensitive bacteria to the effects of biosurfactant extract of Pseudomonas aeruginosa83, was Staphylococcus aureus and the most resistant bacteria to these extract, was the Proteus mirabilis. The results of MIC, MBC showed that MIC of the extract in concentration of 63 and 125 mg/ml on Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus respectively. Also, the MBC were extract in concentration of 63 and 125mg/ml on Staphylococcus epidermidis and Staphylococcus aureus respectively.Discussion and conclusion: Pseudomonas aeruginosa had high potential in reducing the surface tension and biosurfactant extracted had high antibacterial effects. Therefore, it

  10. Purification and partial characterization of bacillocin 490, a novel bacteriocin produced by a thermophilic strain of Bacillus licheniformis

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    De Felice Maurilio

    2002-04-01

    Full Text Available Abstract Background Applications of bacteriocins as food preservatives have been so far limited, principally because of their low antimicrobial activity in foods. Nisin is the only bacteriocin of significant use, but applications are restricted principally because of its very low activity at neutral or alkaline pH. Thus the isolation of new bacteriocins active in foods is desirable. Results We isolated a Bacillus licheniformis thermophilic strain producing a bacteriocin with some novel features, named here bacillocin 490. This bacteriocin was inactivated by pronase E and proteinase K and was active against closely related Bacillus spp. both in aerobic and in anaerobic conditions. Bactericidal activity was kept during storage at 4°C and was remarkably stable in a wide pH range. The bacteriocin was partially purified by elution after adhesion to cells of the food-isolated strain Bacillus smithii and had a rather low mass (2 KDa. Antimicrobial activity against B. smithii was observed also when this organism was grown in water buffalo milk. Conclusions Bacillocin 490 is a novel candidate as a food anti-microbial agent since it displays its activity in milk, is stable to heat treatment and during storage, is active in a wide pH range and has bactericidal activity also at high temperature. These features may allow the use of bacillocin 490 during processes performed at high temperature and as a complementary antimicrobial agent of nisin against some Bacillus spp. in non-acidic foods. The small size suggests its use on solid foods.

  11. In vitro Effectiveness of Commercial Bacteriophage Cocktails on Diverse Extended-Spectrum Beta-Lactamase Producing Escherichia coli Strains.

    Science.gov (United States)

    Gundogdu, Aycan; Bolkvadze, Darajen; Kilic, Huseyin

    2016-01-01

    The objective of this study is to determine the in vitro susceptibility of Georgian bacteriophage cocktails on multidrug resistant (MDR) extended-spectrum beta-lactamase producing Escherichia coli (ESBL-EC) isolated from patients' blood and urine cultures. A total of 615 E. coli isolates were included in this study. Phene Plate (PhP)-typing and phylogenetic grouping were used for the typing. Antimicrobial resistance profiles and ESBL production of all isolates were confirmed according to Clinical and Laboratory Standards Institute (CLSI) criteria. The activities of four bacteriophage cocktails (Enko-phage, SES-bacteriophage, Pyo-bacteriophage, and Intesti-bacteriophage) were determined against 142 ESBL-EC using in vitro spot tests. According to this, Enko-phage were active against 87.3% of the tested strains while that ratio was 81.7% for Intesti-bacteriophage, 81.7% for Pyo-bacteriophage, and 59.2% for SES-bacteriophage cocktails. Based on the contingency tests, the phage cocktails were observed to be statistically significantly ( p < 0.001) more effective on ESBL-EC strains belonging to phylogenetic groups D and B2. The employed phage cocktails were found to be affective against all tested resistant types. These results are promising especially for the infections that are caused by MDR pathogens that are difficult to treat. As this is a preliminary step to the potential clinical trials to be designed for the country, in vitro confirmation of their success on a MDR ESBL-EC collection should be accepted as an initial action, which is encouraging to consider clinical trials of phage therapy especially in countries which are not introduce phage therapy.

  12. in vitro effectiveness of commercial bacteriophage cocktails on diverse extended spectrum beta-lactamase (ESBL producing Escherichia coli strains

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    Aycan Gundogdu

    2016-11-01

    Full Text Available The objective of this study is to determine the in vitro susceptibility of Georgian bacteriophage cocktails on multi-drug resistant extended-spectrum β-lactamase producing Escherichia coli (ESBL-EC isolated from patients' blood and urine cultures. 615 E. coli isolates were included in this study. PhP-typing and phylogenetic grouping were used for the typing. Antimicrobial resistance profiles and ESBL production of all isolates were confirmed according to CLSI criteria. The activities of four bacteriophage cocktails (Enko-phage, SES-bacteriophage, Pyo-bacteriophage and Intesti-bacteriophage were determined against 142 ESBL- EC using in vitro spot tests. According to this, Enko-phage were active against 87.3% of the tested strains while that ratio was 81.7% for intesti-bacteriophage, 81.7% for Pyo-bacteriophage and 59.2% for SES-bacteriophage cocktails. Based on the contingency tests, the phage cocktails were observed to be statistically significantly (p<0.001 more effective on ESBL-EC strains belonging to phylogenetic groups D and B2. The employed phage cocktails were found to be affective against all tested resistant types. These results are promising especially for the infections that are caused by multi-drug resistant pathogens that are difficult to treat. As this is a preliminary step to the potential clinical trials to be designed for the country, in vitro confirmation of their success on a multi-drug-resistant ESBL-EC collection should be accepted as an initial action, which is encouraging to consider clinical trials of phage therapy especially in countries which are not introduce phage therapy.

  13. Carbon-flux distribution within Streptomyces coelicolor metabolism: a comparison between the actinorhodin-producing strain M145 and its non-producing derivative M1146.

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    Fabien Coze

    Full Text Available Metabolic Flux Analysis is now viewed as essential to elucidate the metabolic pattern of cells and to design appropriate genetic engineering strategies to improve strain performance and production processes. Here, we investigated carbon flux distribution in two Streptomyces coelicolor A3 (2 strains: the wild type M145 and its derivative mutant M1146, in which gene clusters encoding the four main antibiotic biosynthetic pathways were deleted. Metabolic Flux Analysis and (13C-labeling allowed us to reconstruct a flux map under steady-state conditions for both strains. The mutant strain M1146 showed a higher growth rate, a higher flux through the pentose phosphate pathway and a higher flux through the anaplerotic phosphoenolpyruvate carboxylase. In that strain, glucose uptake and the flux through the Krebs cycle were lower than in M145. The enhanced flux through the pentose phosphate pathway in M1146 is thought to generate NADPH enough to face higher needs for biomass biosynthesis and other processes. In both strains, the production of NADPH was higher than NADPH needs, suggesting a key role for nicotinamide nucleotide transhydrogenase for redox homeostasis. ATP production is also likely to exceed metabolic ATP needs, indicating that ATP consumption for maintenance is substantial.Our results further suggest a possible competition between actinorhodin and triacylglycerol biosynthetic pathways for their common precursor, acetyl-CoA. These findings may be instrumental in developing new strategies exploiting S. coelicolor as a platform for the production of bio-based products of industrial interest.

  14. The use of lactic acid-producing, malic acid-producing, or malic acid-degrading yeast strains for acidity adjustment in the wine industry.

    Science.gov (United States)

    Su, Jing; Wang, Tao; Wang, Yun; Li, Ying-Ying; Li, Hua

    2014-03-01

    In an era of economic globalization, the competition among wine businesses is likely to get tougher. Biotechnological innovation permeates the entire world and intensifies the severity of the competition of the wine industry. Moreover, modern consumers preferred individualized, tailored, and healthy and top quality wine products. Consequently, these two facts induce large gaps between wine production and wine consumption. Market-orientated yeast strains are presently being selected or developed for enhancing the core competitiveness of wine enterprises. Reasonable biological acidity is critical to warrant a high-quality wine. Many wild-type acidity adjustment yeast strains have been selected all over the world. Moreover, mutation breeding, metabolic engineering, genetic engineering, and protoplast fusion methods are used to construct new acidity adjustment yeast strains to meet the demands of the market. In this paper, strategies and concepts for strain selection or improvement methods were discussed, and many examples based upon selected studies involving acidity adjustment yeast strains were reviewed. Furthermore, the development of acidity adjustment yeast strains with minimized resource inputs, improved fermentation, and enological capabilities for an environmentally friendly production of healthy, top quality wine is presented.

  15. Isolation of a high malic and low acetic acid-producing sake yeast Saccharomyces cerevisiae strain screened from respiratory inhibitor 2,4-dinitrophenol (DNP)-resistant strains.

    Science.gov (United States)

    Kosugi, Shingo; Kiyoshi, Keiji; Oba, Takahiro; Kusumoto, Kenichi; Kadokura, Toshimori; Nakazato, Atsumi; Nakayama, Shunichi

    2014-01-01

    We isolated 2,4-dinitrophenol (DNP)-resistant sake yeast strains by UV mutagenesis. Among the DNP-resistant mutants, we focused on strains exhibiting high malic acid and low acetic acid production. The improved organic acid composition is unlikely to be under the control of enzyme activities related to malic and acetic acid synthesis pathways. Instead, low mitochondrial activity was observed in DNP-resistant mutants, indicating that the excess pyruvic acid generated during glycolysis is not metabolized in the mitochondria but converted to malic acid in the cytosol. In addition, the NADH/NAD(+) ratio of the DNP-resistant strains was higher than that of the parental strain K901. These results suggest that the increased NADH/NAD(+) ratio together with the low mitochondrial activity alter the organic acid composition because malic acid synthesis requires NADH, while acetic acid uses NAD(+). Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  16. Enhanced Control of Listeria monocytogenes by Enterococcus faecium KE82, a Multiple Enterocin-Producing Strain, in Different Milk Environments.

    Science.gov (United States)

    Vandera, Elpiniki; Lianou, Alexandra; Kakouri, Athanasia; Feng, Jinbo; Koukkou, Anna-Irini; Samelis, John

    2017-01-01

    Enterococcus faecium KE82, isolated from traditional Greek Graviera cheese, was identified in pure broth cultures in vitro as a multiple enterocin-producing bacterial strain possessing the structural entA, entB, and entP enterocin genes. E. faecium KE82 was further assessed for in situ antilisterial activity in raw milk (RM) and commercially thermized milk (TM; 63°C for 30 s) in the presence of the indigenous microbiota and in sterile raw milk (SRM; 121°C for 5 min) with or without the addition of two commercial starter culture (CSC) strains Streptococcus thermophilus and Lactococcus lactis . Growth of Listeria monocytogenes was completely inhibited in RM incubated at 37°C for 6 h, whereas the pathogen was significantly inactivated in RM+KE82 samples during further incubation at 18°C for 66 h. In contrast, L. monocytogenes levels increased by approximately 2 log CFU/ml in TM, but in TM+KE82 samples, pathogen growth was retarded during the first 6 h at 37°C followed by growth cessation and partial inactivation at 18°C. After 48 to 72 h, growth of L. monocytogenes in SRM+CSC samples decreased by 4 to 5 log CFU/ml compared with the SRM control, whereas additional 10-fold decreases in the pathogen were observed in SRM+CSC+KE82 samples. Reverse transcription PCR analysis of SRM+KE82 and SRM+CSC+KE82 samples confirmed that the entA and entB genes were transcribed, but entP gene transcription was not detected. All RM and SRM samples inoculated with E. faecium KE82 displayed strong in situ inhibitory activity against L. monocytogenes in well diffusion bioassays, whereas activity was weaker to undetectable in comparable or additional TM+KE82 samples; no milk sample without E. faecium KE82 had activity against L. monocytogenes . The findings of this study indicate that E. faecium KE82 is an antilisterial agent that could be used in traditional dairy foods because it concomitantly produces enterocins A and B in situ in milk.

  17. Identification and statistical optimization of fermentation conditions for a newly isolated extracellular cholesterol oxidase-producing Streptomyces cavourensis strain NEAE-42

    OpenAIRE

    El-Naggar, Noura El-Ahmady; El-Shweihy, Nancy M.; El-Ewasy, Sara M.

    2016-01-01

    Background Due to broad range of clinical and industrial applications of cholesterol oxidase, isolation and screening of bacterial strains producing extracellular form of cholesterol oxidase is of great importance. Results One hundred and thirty actinomycete isolates were screened for their cholesterol oxidase activity. Among them, a potential culture, strain NEAE-42 is displayed the highest extracellular cholesterol oxidase activity. It was selected and identified as Streptomyces cavourensis...

  18. Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients in the Zagreb region

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    Branka Bedenić,

    2010-02-01

    Full Text Available Aim To determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients during a three-year period, to determine their antibiotic susceptibility, investigate the transfer of ESBL genes with cotransfer of resistance and to characterize isolated beta-lactamases. Methods Antimicrobial susceptibility was determined by disk diffusion and broth microdilution methods. The double-disk test was used for ESBL detection. Transfer of resistance was performed by broth mating method and characterization of isolated beta-lactamases by polymerase chain reaction. Results The prevalence of ESBL-producing E. coli was 1.5% and of K. pneumoniae 4.1% with its different distribution according to patients`age and gender. ESBL-producing K. pneumoniae showed high resistance rates to aminoglycosides, cotrimoxazole, nitrofurantoin and quinolones while ESBL-producing E. coli isolates, with exception of high aminoglycoside resistance, showed low resistance rates to other antibiotics. Successful conjugation of ESBL genes was obtained with 25% E. coli and 76.2% K. pneumoniae strains. Comparing to E. coli, K. pneumoniae strains showed higher rates of aminoglycosideand cotrimoxazole resistance cotransfer. Beta-lactamases of investigated strains belonged to TEM, SHV and CTX-M families.Conclusion The existence of multiple-resistant ESBL-producing E. coli and K. pneumoniae strains was confirmed in observed outpatient population. ESBL-producing K. pneumoniae isolates, in contrast toESBL-producing E. coli, showed higher resistance rates to non-beta-lactam antibiotics, probably caused by cotransfer of resistance genes located on the same plasmid as ESBL genes. It is important to monitor the prevalence of such strains and their possible spreading in the outpatient population of the Zagreb region

  19. An application in cheddar cheese manufacture for a strain of Lactococcus lactis producing a novel broad-spectrum bacteriocin, lacticin 3147.

    Science.gov (United States)

    Ryan, M P; Rea, M C; Hill, C; Ross, R P

    1996-01-01

    Lactococcus lactis DPC3147, a strain isolated from an Irish kefir grain, produces a bacteriocin with a broad spectrum of inhibition. The bacteriocin produced is heat stable, particularly at a low pH, and inhibits nisin-producing (Nip+) lactococci. On the basis of the observation that the nisin structural gene (nisA) does not hybridize to DPC3147 genomic DNA, the bacteriocin produced was considered novel and designated lacticin 3147. The genetic determinants which encode lacticin 3147 are contained on a 63-kb plasmid, which was conjugally mobilized to a commercial cheese starter, L. lactis subsp. cremoris DPC4268. The resultant transconjugant, DPC4275, both produces and is immune to lacticin 3147. The ability of lacticin 3147-producing lactococci to perform as cheddar cheese starters was subsequently investigated in cheesemaking trials. Bacteriocin-producing starters (which included the transconjugant strain DPC4275) produced acid at rates similar to those of commercial strains. The level of lacticin 3147 produced in cheese remained constant over 6 months of ripening and correlated with a significant reduction in the levels of nonstarter lactic acid bacteria. Such results suggest that these starters provide a means of controlling developing microflora in ripened fermented products. PMID:8593062

  20. Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.

    Directory of Open Access Journals (Sweden)

    Maqshoof Ahmad

    2013-12-01

    Full Text Available Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

  1. Effect of different in vitro culture extracts of black pepper (Piper nigrum L.) on toxic metabolites-producing strains.

    Science.gov (United States)

    Ahmad, Nisar; Abbasi, Bilal Haider; Fazal, Hina

    2016-03-01

    In the present study, the effect of different in vitro cultures (callus, in vitro shoots) and commercially available peppercorn extract was investigated for its activity against toxic metabolite-producing strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Candida albicans). These in vitro cultures were extracted with ethanol, hexane, and chloroform, and the antipathogenic activity was determined by well-diffusion method. Hexane extract of callus showed 22 mm zone of inhibition against B. cereus, 23 mm against S. aureus, while regenerated shoots and seeds have shown 24.3 and 26 mm zones of inhibition. The ethanolic extracts of regenerated Piper shoots have shown 25 mm activity against S. aureus, 21 mm against B. cereus, and 16 mm in the case of C. albicans in comparison with standard antibiotics. Peppercorn extracts in chloroform and ethanol had shown activities against B. cereus (23.6 mm) and B. subtilis (23.5 mm). During in vitro organogenesis and morphogenesis, cells and tissues produced a comparable phytochemicals profile like mother plant. Morphogenesis is critically controlled by the application of exogenous plant-growth regulators. Such addition alters the hormonal transduction pathways, and cells under in vitro conditions regenerate tissues, which are dependant on the physiological state of cells, and finally enhance the production of secondary metabolites. To the best of our knowledge, this is the first report to compare the antimicrobial potential of in vitro regenerated tissues and peppercorn with standard antibiotics. In conclusion, most of the extracts showed pronounced activities against all the pathogenic microbes. This is a preliminary work, and the minimum inhibitory concentration values needs to be further explored. Regenerated tissues of P. nigrum are a good source of biologically active metabolites for antimicrobial activities, and callus culture presented itself as

  2. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins

    Directory of Open Access Journals (Sweden)

    Andong eGong

    2015-10-01

    Full Text Available Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these pests is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production in the field and during storage.

  3. Reactogenicity and immunogenicity of inactivated poliovirus vaccine produced from Sabin strains: a phase I Trial in healthy adults in Cuba.

    Science.gov (United States)

    Resik, Sonia; Tejeda, Alina; Fonseca, Magilé; Alemañi, Nilda; Diaz, Manuel; Martinez, Yenisleidys; Garcia, Gloria; Okayasu, Hiromasa; Burton, Anthony; Bakker, Wilfried A M; Verdijk, Pauline; Sutter, Roland W

    2014-09-22

    To ensure that developing countries have the option to produce inactivated poliovirus vaccine (IPV), the Global Polio Eradication Initiative has promoted the development of an IPV using Sabin poliovirus strains (Sabin IPV). This trial assessed the reactogenicity and immunogenicity of Sabin IPV and adjuvanted Sabin IPV in healthy adults in Cuba. This is a randomized, controlled phase I trial, enrolling 60 healthy (previously vaccinated) male human volunteers, aged 19-23 years to receive one dose of either Sabin IPV (20:32:64 DU/dose), adjuvanted Sabin IPV (10:16:32 DU/dose), or conventional Salk IPV (40:8:32 DU/dose). The primary endpoint for reactogenicity relied on monitoring of adverse events. The secondary endpoint measured boosting immune responses (i.e. seroconversion or 4-fold rise) of poliovirus antibody, assessed by neutralization assays. Sixty subjects fulfilled the study requirements. No serious adverse events reported were attributed to trial interventions during the 6-month follow-up period. Twenty-eight days after vaccination, boosting immune responses against poliovirus types 1-3 were between 90% and 100% in all vaccination groups. There was a more than 6-fold increase in median antibody titers between pre- and post-vaccination titers in all vaccination groups. Both Sabin IPV and adjuvanted Sabin IPV were well tolerated and immunogenic against all poliovirus serotypes. This result suggests that the aluminum adjuvant may allow a 50% (or higher) dose reduction. Copyright © 2014. Published by Elsevier Ltd.

  4. Enterocin C, a class IIb bacteriocin produced by E. faecalis C901, a strain isolated from human colostrum.

    Science.gov (United States)

    Maldonado-Barragán, Antonio; Caballero-Guerrero, Belén; Jiménez, Esther; Jiménez-Díaz, Rufino; Ruiz-Barba, José L; Rodríguez, Juan M

    2009-07-31

    Enterocin C (EntC), a class IIb bacteriocin was purified from culture supernatants of Enterococcus faecalis C901, a strain isolated from human colostrum. Enterocin C consists of two distinct peptides, named EntC1 and EntC2, whose complementary action is required for full antimicrobial activity. The structural genes entC1 and entC2 encoding enterocins EntC1 and EntC2, respectively, and that encoding the putative immunity protein (EntCI) are located in the 9-kb plasmid pEntC, harboured by E. faecalis C901. The N-terminal sequence of both antimicrobial peptides revealed that EntC1 (4284 Da) is identical to Ent1071A, one of the two peptides that form enterocin 1071 (Ent1071), a bacteriocin produced by E. faecalis BFE 1071. In contrast, EntC2 (3867 Da) presents the non-polar alanine residue at position 17 (Ala(17)) instead of the polar threonine residue (Thr(17)) in Ent1071B, the second peptide constituting Ent1071. In spite of peptide similarities, EntC differs from Ent1071 in major aspects, including the complementary activity among its constitutive peptides and its wider inhibitory spectrum of activity. Different amphiphilic alpha-helical conformations between EntC2 and Ent1071B could explain both, acquired complementary activity and increased antimicrobial spectrum.

  5. Isolation and molecular identification chitinase-producing Streptomyces strains and examination of their in-vitro antagonistic effects

    Directory of Open Access Journals (Sweden)

    Alireza Dehnad

    2015-12-01

    Full Text Available Introduction: The chemical fungicides are used widely in the world. To reduce the application of synthetic fungicides in treating plant diseases, biological methods are considered as an alternative way to control plant diseases. Many actinomycetes, particularly Streptomyces species are biological agents against a broad spectrum of fungal plant pathogens. The purpose of this study was using the kitinolitik actinomycetes isolated from soil of Eastern Azerbaijan province In order to produce biological pesticides. Materials and methods: Soil samples were taken from different areas of Eastern Azerbaijan province. According to Streptomyces morphological features, single colonies were isolated. To identify the bacteria by molecular characteristic, the genomic DNA was extracted and then the sequences of 16S rDNA were replicated. By using specific primers the bacterial isolates containing chitinase gene were screened. The isolates consisted Chitinase enzyme and were antagonistically cultured with Alternaria genus which is a fungal plant pathogen. Results: Out of 60 soil collected samples, 31 Streptomyces bacterial isolates were separated. Four isolates showed positive results to selectivity action of the chitinase enzyme. Treatment of 3 bacterial isolates with 2 pathogenic fungi showed that AE09 is the most effective anti-fungal isolates. Discussion and conclusion: Soils in Eastern Azerbaijan province are rich of Streptomyces bacteria which generate antifungal compounds. Obtaining the Streptomyces bacteria which have chitinase gene, can lead to identification of very effective strains as anti-fungal.

  6. Screening and characterization of alkaline protease produced by a pink pigmented facultative methylotrophic (PPFM) strain, MSF 46

    OpenAIRE

    Jayashree, Shanmugam; Annapurna, Balumuri; Jayakumar, Renganathan; Sa, Tongmin; Seshadri, Sundaram

    2014-01-01

    Among the various bacterial isolates, the strain MSF 46 isolated from thorn forest soil samples, Tamil Nadu, India, was screened and characterized for its proteolytic activity. While the 16S rRNA sequencing and biochemical characterization revealed that the strain closely resembles Methylobacterium sp., methylotrophy of the strain was confirmed by the sequence homology of mxaF gene with other relative Methylobacterium sp. The alkaline protease was purified to homogeneity using DEAE cellulose ...

  7. Metabolic network reconstruction and genome-scale model of butanol-producing strain Clostridium beijerinckii NCIMB 8052

    Directory of Open Access Journals (Sweden)

    Kim Pan-Jun

    2011-08-01

    Full Text Available Abstract Background Solventogenic clostridia offer a sustainable alternative to petroleum-based production of butanol--an important chemical feedstock and potential fuel additive or replacement. C. beijerinckii is an attractive microorganism for strain design to improve butanol production because it (i naturally produces the highest recorded butanol concentrations as a byproduct of fermentation; and (ii can co-ferment pentose and hexose sugars (the primary products from lignocellulosic hydrolysis. Interrogating C. beijerinckii metabolism from a systems viewpoint using constraint-based modeling allows for simulation of the global effect of genetic modifications. Results We present the first genome-scale metabolic model (iCM925 for C. beijerinckii, containing 925 genes, 938 reactions, and 881 metabolites. To build the model we employed a semi-automated procedure that integrated genome annotation information from KEGG, BioCyc, and The SEED, and utilized computational algorithms with manual curation to improve model completeness. Interestingly, we found only a 34% overlap in reactions collected from the three databases--highlighting the importance of evaluating the predictive accuracy of the resulting genome-scale model. To validate iCM925, we conducted fermentation experiments using the NCIMB 8052 strain, and evaluated the ability of the model to simulate measured substrate uptake and product production rates. Experimentally observed fermentation profiles were found to lie within the solution space of the model; however, under an optimal growth objective, additional constraints were needed to reproduce the observed profiles--suggesting the existence of selective pressures other than optimal growth. Notably, a significantly enriched fraction of actively utilized reactions in simulations--constrained to reflect experimental rates--originated from the set of reactions that overlapped between all three databases (P = 3.52 × 10-9, Fisher's exact test

  8. Enzymes produced by halotolerant spore-forming gram-positive bacterial strains isolated from a resting habitat (Restinga de Jurubatiba) in Rio de Janeiro, Brazil: focus on proteases.

    Science.gov (United States)

    D Santos, Anderson Fragoso; Pacheco, Clarissa Almeida; Valle, Roberta D Santos; Seldin, Lucy; D Santos, André Luis Souza

    2014-12-01

    The screening for hydrolases-producing, halotolerant, and spore-forming gram-positive bacteria from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides, a plant found in the Restinga de Jurubatiba located at the northern region of Rio de Janeiro State, Brazil, resulted in the isolation of 22 strains. These strains were identified as Halobacillus blutaparonensis (n = 2), Oceanobacillus picturae (n = 5), and Oceanobacillus iheyensis (n = 15), and all showed the ability to produce different extracellular enzymes. A total of 20 isolates (90.9 %) showed activity for protease, 5 (22.7 %) for phytase, 3 (13.6 %) for cellulase, and 2 (9.1 %) for amylase. Some bacterial strains were capable of producing three (13.6 %) or two (9.1 %) distinct hydrolytic enzymes. However, no bacterial strain with ability to produce esterase and DNase was observed. The isolate designated M9, belonging to the species H. blutaparonensis, was the best producer of protease and also yielded amylase and phytase. This strain was chosen for further studies regarding its protease activity. The M9 strain produced similar amounts of protease when grown either without or with different NaCl concentrations (from 0.5 to 10 %). A simple inspection of the cell-free culture supernatant by gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of three major alkaline proteases of 40, 50, and 70 kDa, which were fully inhibited by phenylmethylsulfonyl fluoride (PMSF) and tosyl-L-phenylalanine chloromethyl ketone (TPCK) (two classical serine protease inhibitors). The secreted proteases were detected in a wide range of temperature (from 4 to 45 °C) and their hydrolytic activities were stimulated by NaCl (up to 10 %). The serine proteases produced by the M9 strain cleaved gelatin, casein, albumin, and hemoglobin, however, in different extensions. Collectively, these results suggest the potential use of the M9 strain in biotechnological

  9. Pediocin PA-1 and a pediocin producing Lactobacillus plantarum strain do not change the HMA rat microbiota

    DEFF Research Database (Denmark)

    Bernbom, Nete; Jelle, N.B.; Brogren, C.-H.

    2009-01-01

    microbiota was in all treatments dominated by lactic acid bacteria and coliforms and no changes in the rat commensal microbiota were detected after ingestion of either of the two L plantarum strains as determined by both culturable methods and molecular methods (DGGE). Both strains were detected...

  10. Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering.

    Science.gov (United States)

    Bala Subramanian, S; Yan, S; Tyagi, R D; Surampalli, R Y

    2010-04-01

    Wastewater treatment plants often face the problems of sludge settling mainly due to sludge bulking. Generally, synthetic organic polymer and/or inorganic coagulants (ferric chloride, alum and quick lime) are used for sludge settling. These chemicals are very expensive and further pollute the environment. Whereas, the bioflocculants are environment friendly and may be used to flocculate the sludge. Extracellular polymeric substances (EPS) produced by sludge microorganisms play a definite role in sludge flocculation. In this study, 25 EPS producing strains were isolated from municipal wastewater treatment plant. Microorganisms were selected based on EPS production properties on solid agar medium. Three types of EPS (slime, capsular and bacterial broth mixture of both slime and capsular) were harvested and their characteristics were studied. EPS concentration (dry weight), viscosity and their charge (using a Zetaphoremeter) were also measured. Bioflocculability of obtained EPS was evaluated by measuring the kaolin clay flocculation activity. Six bacterial strains (BS2, BS8, BS9, BS11, BS15 and BS25) were selected based on the kaolin clay flocculation. The slime EPS was better for bioflocculation than capsular EPS and bacterial broth. Therefore, extracted slime EPS (partially purified) from six bacterial strains was studied in terms of sludge settling [sludge volume index (SVI)] and dewatering [capillary suction time (CST)]. Biopolymers produced by individual strains substantially improved dewaterability. The extracted slime EPS from six different strains were partially characterized. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  11. Complete genome sequence of N2-fixing model strain Klebsiella sp. nov. M5al, which produces plant cell wall-degrading enzymes and siderophores

    Directory of Open Access Journals (Sweden)

    Zhili Yu

    2018-03-01

    Full Text Available The bacterial strain M5al is a model strain for studying the molecular genetics of N2-fixation and molecular engineering of microbial production of platform chemicals 1,3-propanediol and 2,3-butanediol. Here, we present the complete genome sequence of the strain M5al, which belongs to a novel species closely related to Klebsiella michiganensis. M5al secretes plant cell wall-degrading enzymes and colonizes rice roots but does not cause soft rot disease. M5al also produces siderophores and contains the gene clusters for synthesis and transport of yersiniabactin which is a critical virulence factor for Klebsiella pathogens in causing human disease. We propose that the model strain M5al can be genetically modified to study bacterial N2-fixation in association with non-legume plants and production of 1,3-propanediol and 2,3-butanediol through degradation of plant cell wall biomass.

  12. How different is the proteome of the extended spectrum β-lactamase producing Escherichia coli strains from seagulls of the Berlengas natural reserve of Portugal?

    Science.gov (United States)

    Monteiro, R; Hébraud, M; Chafsey, I; Poeta, P; Igrejas, G

    2016-08-11

    β-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Escherichia coli strains 5A, 10A, 12A and 23B isolated from Seagulls feces, are cefotaxime-resistant strains that produces extended-spectrum beta-lactamases. Bacterial resistance to these antibiotics occurs predominantly through structural modification on the penicillin-binding proteins and enzymatic inactivation by extended-spectrum β-lactamases. Using classical proteomic techniques (2D-GE) coupled to mass spectrometry and bioinformatics extended analysis, in this study, we report several significant differences in cytoplasmic proteins expression when the strains were submitted to antibiotic stress and when the resistant strains were compared with a non-resistant strain. A total of 79 differentially expressed spots were collected for protein identification. Significant level of expression was found in antibiotic resistant proteins like β-lactamase CTX-M-1 and TEM and also in proteins related with oxidative stress. This approach might help us understand which pathways form barriers for antibiotics, another possible new pathways involved in antibiotic resistance to devise appropriate strategies for their control already recognized by the World Health Organization and the European Commission. This study highlights the protein differences when a resistant strain is under antibiotic pressure and how different can be a sensible and resistant strain at the protein level. This survey might help us to understand the specifics barriers for antibiotics and which pathways are involved in its resistance crosswise the wildlife. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples

    Science.gov (United States)

    Krüger, Alejandra; Lucchesi, Paula M. A.; Sanso, A. Mariel; Etcheverría, Analía I.; Bustamante, Ana V.; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W.; Padola, Nora L.; Rossen, John W. A.

    2015-01-01

    The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx1a or stx2a subtypes. Interestingly, stx2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx2-positive isolates, whereas katP was only found in stx1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx2a. PMID:26539413

  14. Growth and Survival of Acid-Resistant and Non-Acid-Resistant Shiga-Toxin-Producing Escherichia coli Strains during the Manufacture and Ripening of Camembert Cheese.

    Science.gov (United States)

    Montet, M P; Jamet, E; Ganet, S; Dizin, M; Miszczycha, S; Dunière, L; Thevenot, D; Vernozy-Rozand, C

    2009-01-01

    Growth and survival of acid-resistant (AR) and non-acid-resistant (NAR) Shiga-toxin-producing Escherichia coli (STEC) strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 10(3) CFU mL(-1). The STEC counts (AR and NAR) initially increased by 1 to 2 log(10) CFU g(-1) during cheese-making. Thereafter, the populations stabilized during salting/drying and then decreased during the early stages of ripening. Exposing the STEC strains in artificially inoculated cheeses to simulated gastric fluid (SGF - pH: 2.0) reduced the number of NAR strains to undetectable levels within 40 minutes, versus 120 minutes for the AR STEC strains. AR and NAR STEC were able to survive during the manufacture and ripening of Camembert cheese prepared from microfiltered milk with no evidence of induced acid tolerance in NAR STEC strains.

  15. Growth and Survival of Acid-Resistant and Non-Acid-Resistant Shiga-Toxin-Producing Escherichia coli Strains during the Manufacture and Ripening of Camembert Cheese

    Directory of Open Access Journals (Sweden)

    M. P. Montet

    2009-01-01

    Full Text Available Growth and survival of acid-resistant (AR and non-acid-resistant (NAR Shiga-toxin-producing Escherichia coli (STEC strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 103 CFU mL−1. The STEC counts (AR and NAR initially increased by 1 to 2 log⁡10 CFU g−1 during cheese-making. Thereafter, the populations stabilized during salting/drying and then decreased during the early stages of ripening. Exposing the STEC strains in artificially inoculated cheeses to simulated gastric fluid (SGF - pH: 2.0 reduced the number of NAR strains to undetectable levels within 40 minutes, versus 120 minutes for the AR STEC strains. AR and NAR STEC were able to survive during the manufacture and ripening of Camembert cheese prepared from microfiltered milk with no evidence of induced acid tolerance in NAR STEC strains.

  16. PF1163A and B, new antifungal antibiotics produced by Penicillium sp. I. Taxonomy of producing strain, fermentation, isolation and biological activities.

    Science.gov (United States)

    Nose, H; Seki, A; Yaguchi, T; Hosoya, A; Sasaki, T; Hoshiko, S; Shomura, T

    2000-01-01

    Two novel antifungal antibiotics, PF1163A and B, were isolated from the fermentation broth of Penicillium sp. They were purified from the solid cultures of rice media using ethyl acetate extraction, silica gel and Sephadex LH-20 column chromatographies. PF1163A and B showed potent growth inhibitory activity against pathogenic fungal strain Candida albicans but did not show cytotoxic activity against mammalian cells. These compounds inhibited the ergosterol biosynthesis in Candida albicans.

  17. Genome Sequence Analysis of the Biogenic Amine-Producing Strain Lactococcus lactis subsp. cremoris CECT 8666 (Formerly GE2-14)

    Science.gov (United States)

    del Rio, Beatriz; Linares, Daniel M.; Fernandez, Maria; Mayo, Baltasar; Martin, M. Cruz; Alvarez, Miguel A.

    2014-01-01

    We here report a 2,801,031-bp annotated draft assembly for the Lactococcus lactis subsp. cremoris GE2-14 genome. This dairy strain produces the biogenic amine putrescine. This sequence may help identify the mechanisms regulating putrescine biosynthesis and throw light on ways to reduce its presence in fermented foods. PMID:25342694

  18. Purification, cloning and characterisation of two forms of thermostable and highly active cellobiohydrolase I (Cel7A) produced by the industrial strain of Chrysosporium lucknowense

    NARCIS (Netherlands)

    Gusakov, A.V.; Sinitsyn, A.P.; Salanovich, T.N.; Bukhtojarov, F.E.; Markov, A.V.; Ustinov, B.B.; Zeijl, C.V.; Punt, P.; Burlingame, R.

    2005-01-01

    Two forms of cellobiohydrolase I (CBH I, Cel7A) were purified from the culture ultrafiltrate of a mutant strain of the fungus Chrysosporium lucknowense, an industrial producer of cellulases and hemicellulases. The enzymes had different molecular masses (52 and 65 kDa, SDS-PAGE data) but the same pI

  19. Draft genome sequences of Escherichia coli O113:H21 strains recovered from a major produce-production region in California

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli is a foodborne and waterborne pathogen and is responsible for outbreaks of human gastroenteritis. This report documents the draft genome sequences of seven O113:H21 strains recovered from livestock, wildlife, and soil samples collected in a major agricultural r...

  20. Genome sequences of three tunicamycin-producing Streptomyces strains; S. chartreusis NRRL 12338, S. chartreusis NRRL 3882, and S. lysosuperificus ATCC 31396

    Science.gov (United States)

    S. chartreusis strains NRRL 12338 and NRRL 3882, S. clavuligerus NRRL 3585, and S. lysosuperificus ATCC 31396, are known producers of tunicamycins, and also of charteusins, clavulinate, cephalosporins, holomycins, and calcimycin. Here we announce the sequencing of the S. lysosuperificus and the two...

  1. Strain of Fusarium oxysporum Isolated From Almond Hulls Produces Styrene and 7-Methyl-1,3,5-Cyclooctatriene as the Principal Volatile Components

    Science.gov (United States)

    An isolated strain of Fusarium oxysporum from the hulls of Prunus dulcis (sweet almond) was found to produce relatively large quantities of the hydrocarbons styrene and three isomers of 7-methyl-1,3,5-cyclooctatriene (MCOT). Production of styrene and MCOT was reproduced on small scale using potato d...

  2. Molecular characterisation of human Shiga toxin-producing Escherichia coli O26 strains: results of an outbreak investigation, Romania, February to August 2016.

    Science.gov (United States)

    Usein, Codruţa-Romaniţa; Ciontea, Adriana Simona; Militaru, Cornelia Mãdãlina; Condei, Maria; Dinu, Sorin; Oprea, Mihaela; Cristea, Daniela; Michelacci, Valeria; Scavia, Gaia; Zota, Lavinia Cipriana; Zaharia, Alina; Morabito, Stefano

    2017-11-01

    IntroductionAt the beginning of 2016, an increase in paediatric haemolytic uremic syndrome (HUS) cases was observed in Romania. The microbiological investigations allowed isolation of Shiga toxin-producing Escherichia coli (STEC) O26 as the causative agent from most cases. Methods: An enhanced national surveillance of HUS and severe diarrhoea was established across the country following the identification of the first cases and was carried out until August 2016. A total of 15 strains were isolated from 10 HUS and five diarrhoea cases. Strains were characterised by virulence markers (i.e. stx type/subtype, eae , ehxA genes), phylogroup, genetic relatedness and clonality using PCR-based assays, PFGE and multilocus sequence typing (MLST). The first six strains were further characterised by whole genome sequencing (WGS). Results: Five PCR-defined genotypes were distinguished. All strains from HUS cases harboured stx2a and eae , with or without stx1a , while strains from diarrhoea cases carried exclusively stx1a and eae genes. PFGE resolved strains into multiple pulsotypes, compatible with a certain geographic segregation of the cases, and strains were assigned to phylogroup B1 and sequence type (ST) 21. WGS confirmed the results of conventional molecular methods, brought evidence of O26:H11 serotype, and complemented the virulence profiles. Discussion/conclusion: This first description of STEC O26 strains from cases in Romania showed that the isolates belonged to a diverse population. The virulence content of most strains highlighted a high risk for severe outcome in infected patients. Improving the national surveillance strategy for STEC infections in Romania needs to be further considered.

  3. Diversity of Shiga Toxin-Producing Escherichia coli (STEC) O26:H11 Strains Examined via stx Subtypes and Insertion Sites of Stx and EspK Bacteriophages

    Science.gov (United States)

    Bonanno, Ludivine; Loukiadis, Estelle; Mariani-Kurkdjian, Patricia; Oswald, Eric; Garnier, Lucille; Michel, Valérie

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen that may be responsible for severe human infections. Only a limited number of serotypes, including O26:H11, are involved in the majority of serious cases and outbreaks. The main virulence factors, Shiga toxins (Stx), are encoded by bacteriophages. Seventy-four STEC O26:H11 strains of various origins (including human, dairy, and cattle) were characterized for their stx subtypes and Stx phage chromosomal insertion sites. The majority of food and cattle strains possessed the stx1a subtype, while human strains carried mainly stx1a or stx2a. The wrbA and yehV genes were the main Stx phage insertion sites in STEC O26:H11, followed distantly by yecE and sbcB. Interestingly, the occurrence of Stx phages inserted in the yecE gene was low in dairy strains. In most of the 29 stx-negative E. coli O26:H11 strains also studied here, these bacterial insertion sites were vacant. Multilocus sequence typing of 20 stx-positive or stx-negative E. coli O26:H11 strains showed that they were distributed into two phylogenetic groups defined by sequence type 21 (ST21) and ST29. Finally, an EspK-carrying phage was found inserted in the ssrA gene in the majority of the STEC O26:H11 strains but in only a minority of the stx-negative E. coli O26:H11 strains. The differences in the stx subtypes and Stx phage insertion sites observed in STEC O26:H11 according to their origin might reflect that strains circulating in cattle and foods are clonally distinct from those isolated from human patients. PMID:25819955

  4. Characteristics of cytotoxic necrotizing factor and cytolethal distending toxin producing Escherichia coli strains isolated from meat samples in Northern Ireland.

    Science.gov (United States)

    Kadhum, H J; Ball, H J; Oswald, E; Rowe, M T

    2006-08-01

    Swabs collected from pig, lamb and beef carcasses and samples of pork, lamb and beef mince were cultured for Escherichia coli strains. Strains harbouring cytotoxic necrotizing factors (CNF1 and 2) and cytolethal distending toxins (CDT-I,-II,-III and -IV) were identified in plate cultures of the isolates by colony hybridization with labelled probes and multiplex PCR assays. Simplex and multiplex PCR assays were used to further characterize the isolates to determine the presence of P, S and F17 fimbriae as well as afimbrial adhesins and haemolysin. The serotype was also determined where possible. Thirty strains with the capacity to code for CNF (4), CDT (24) or both (2) were isolated and characterized, and a wide range of associated factor patterns was observed. The methods utilized were successful in demonstrating the detection of viable strains with potentially significant pathogenic factors from human food sources.

  5. Strain-specific transmission in an outbreak of ESBL-producing Enterobacteriaceae in the hemato-oncology care unit: a cohort study.

    Science.gov (United States)

    Uemura, Makiko; Imataki, Osamu; Uchida, Shumpei; Nakayama-Imaohji, Haruyuki; Ohue, Yukiko; Matsuka, Harumi; Mori, Hatsune; Dobashi, Hiroaki; Kuwahara, Tomomi; Kadowaki, Norimitsu

    2017-01-05

    Extended-spectrum β-lactamase (ESBL)-producing bacteria are resistant to several types of antibiotics excluding carbapenems. A transmissibility of ESBL-producing Enterobacteriaceae would be depending on each bacterial property, however, that has not been elucidated in clinical setting. In this study, we attempted to identify the source of an outbreak of ESBL-producing bacteria in a medical oncology and immunology care unit. An ESBL-producing Enterobacteriaceae (ESBL-E) outbreak observed between July 2012 and August 2012 in Kagawa University Hospital was surveyed using various molecular microbiology techniques. We used Pulsed-field gel electrophoresis (PFGE), PCR-based ESBL gene typing, and direct sequence of ESBL gene as molecular microbiology typing method to distinguish each strain. The typical prevalence of ESBL-E isolation in the unit was 7.0 per month (1.7 per week). The prevalence of ESBL-E isolation during the target research period was 20.0 per month (5.0 per week). In total, 19 isolates (11 K. pneumoniae and 8 E. coli) were obtained from clinical samples, including four control strains (two each of both bacteria), that were physically different from those obtained from other inpatient units in our hospital. Pulsed-field gel electrophoresis (PFGE) for K. pneumoniae (digested by XbaI) produced similar patterns excluding one control strain. PCR classification of the ESBL gene for K. pneumoniae revealed that all strains other than the control strain carried SHV and CTX-M-9. This result was reconfirmed by direct DNA sequencing. Although the outbreak of K. pneumoniae was considered to be "clonal," PFGE and PCR classification of the ESBL genes for E. coli uncovered at least six different "non-clonal" strains possessing individual ESBL gene patterns. According to the result of an antibiogram, the pattern of antimicrobial susceptibility was more variable for K. pneumoniae than for E. coli. Typing by PFGE and ESBL gene PCR analysis is practical for discriminating

  6. Genome Sequence of the Melanin-Producing Extremophile Aeromonas salmonicida subsp. pectinolytica Strain 34melT

    OpenAIRE

    Pavan, María Elisa; Pavan, Esteban E.; López, Nancy Irene; Levin, Laura Noemí; Pettinari, María Julia

    2017-01-01

    The genome of Aeromonas salmonicida subsp. pectinolytica strain 34melT, isolated from a heavily polluted river, contains several genomic islands and putative virulence genes. The identification of genes involved in resistance to different kinds of stress sheds light on the mechanisms used by this strain to thrive in an extreme environment. Fil: Pavan, María Elisa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Pav...

  7. Prevalence and pathogenicity of binary toxin–positive Clostridium difficile strains that do not produce toxins A and B

    Directory of Open Access Journals (Sweden)

    C. Eckert

    2015-01-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhoea and pseudomembranous colitis. The main virulence factors of C. difficile are the toxins A (TcdA and B (TcdB. A third toxin, called binary toxin (CDT, can be detected in 17% to 23% of strains, but its role in human disease has not been clearly defined. We report six independent cases of patients with diarrhoea suspected of having C. difficile infection due to strains from toxinotype XI/PCR ribotype 033 or 033-like, an unusual toxinotype/PCR ribotype positive for CDT but negative for TcdA and TcdB. Four patients were considered truly infected by clinicians and were specifically treated with oral metronidazole. One of the cases was identified during a prevalence study of A−B−CDT+ strains. In this study, we screened a French collection of 220 nontoxigenic strains and found only one (0.5% toxinotype XI/PCR ribotype 033 or 033-like strain. The description of such strains raises the question of the role of binary toxin as a virulence factor and could have implications for laboratory diagnostics that currently rarely include testing for binary toxin.

  8. Growth of Chlamydomonas reinhardtii in acetate-free medium when co-cultured with alginate-encapsulated, acetate-producing strains of Synechococcus sp. PCC 7002.

    Science.gov (United States)

    Therien, Jesse B; Zadvornyy, Oleg A; Posewitz, Matthew C; Bryant, Donald A; Peters, John W

    2014-01-01

    The model alga Chlamydomonas reinhardtii requires acetate as a co-substrate for optimal production of lipids, and the addition of acetate to culture media has practical and economic implications for algal biofuel production. Here we demonstrate the growth of C. reinhardtii on acetate provided by mutant strains of the cyanobacterium Synechococcus sp. PCC 7002. Optimal growth conditions for co-cultivation of C. reinhardtii with wild-type and mutant strains of Synechococcus sp. 7002 were established. In co-culture, acetate produced by a glycogen synthase knockout mutant of Synechococcus sp. PCC 7002 was able to support the growth of a lipid-accumulating mutant strain of C. reinhardtii defective in starch production. Encapsulation of Synechococcus sp. PCC 7002 using an alginate matrix was successfully employed in co-cultures to limit growth and maintain the stability. The ability of immobilized strains of the cyanobacterium Synechococcus sp. PCC 7002 to produce acetate at a level adequate to support the growth of lipid-accumulating strains of C. reinhartdii offers a potentially practical, photosynthetic alternative to providing exogenous acetate into growth media.

  9. Isolation and partial characterization of pigment-like antibiotics produced by a new strain of Streptosporangium isolated from an Algerian soil.

    Science.gov (United States)

    Boudjella, H; Bouti, K; Zitouni, A; Mathieu, F; Lebrihi, A; Sabaou, N

    2007-07-01

    Identification of a new actinomycete strain Sg3, belonging to the genus Streptosporangium and partial characterization of the produced antibacterial activities. The strain Sg3 was isolated from an Algerian Saharan soil and identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Streptosporangium. The comparison of its physiological characteristics with those of known species of Streptosporangium showed significant differences with the nearest species Streptosporangium carneum. Analysis of the 16S rDNA sequence of strain Sg3 showed a similarity level ranging between 97% and 98.8% within Streptosporangium species, with S. carneum the most closely related. Strain Sg3 showed a red coloured antibacterial activity against gram-positive bacteria on several culture media. The purification of the red pigment by chromatographic methods led to the isolation of three active products. The (1)H nuclear magnetic resonance (NMR), mass, infrared (IR) and ultraviolet-visible (UV-VIS) data of these molecules strongly suggested that they belonged to the quinone-anthracycline group with three or more rings. Strain Sg3 represents a distinct phyletic line suggesting a new genomic species. It produces antibacterial activities identified as quinone-anthracycline aromatics. The quinone-anthracycline antibiotics are known for their antimicrobial and antineoplastic activities and are used in chemotherapy for the treatment of many cancer diseases. The present work constitutes the first stage of a whole series of studies to be realized on these antibiotics before arriving at a possible application.

  10. Biodegradation of diesel oil by a novel microbial consortium: comparison between co-inoculation with biosurfactant-producing strain and exogenously added biosurfactants.

    Science.gov (United States)

    Mnif, Inès; Mnif, Sami; Sahnoun, Rihab; Maktouf, Sameh; Ayedi, Younes; Ellouze-Chaabouni, Semia; Ghribi, Dhouha

    2015-10-01

    Bioremediation, involving the use of microorganisms to detoxify or remove pollutants, is the most interesting strategy for hydrocarbon remediation. In this aim, four hydrocarbon-degrading bacteria were isolated from oil-contaminated soil in Tunisia. They were identified by the 16S rDNA sequence analysis, as Lysinibacillus bronitolerans RI18 (KF964487), Bacillus thuringiensis RI16 (KM111604), Bacillus weihenstephanensis RI12 (KM094930), and Acinetobacter radioresistens RI7 (KJ829530). Moreover, a lipopeptide biosurfactant produced by Bacillus subtilis SPB1, confirmed to increase diesel solubility, was tested to increase diesel biodegradation along with co-inoculation with two biosurfactant-producing strains. Culture studies revealed the enhancement of diesel biodegradation by the selected consortium with the addition of SPB1 lipopeptide and in the cases of co-inoculation by biosurfactant-producing strain. In fact, an improvement of about 38.42 and 49.65 % of diesel degradation was registered in the presence of 0.1 % lipopeptide biosurfactant and when culturing B. subtilis SPB1 strain with the isolated consortium, respectively. Furthermore, the best improvement, evaluated to about 55.4 %, was recorded when using the consortium cultured with B. subtilis SPB1 and A. radioresistens RI7 strains. Gas chromatography analyses were correlated with the gravimetric evaluation of the residual hydrocarbons. Results suggested the potential applicability of the selected consortium along with the ex situ- and in situ-added biosurfactant for the effective bioremediation of diesel-contaminated water and soil.

  11. Effect Of GAMMA-Irradiation On Production And Characteristics Of Chitosan Produced From Crustacean Waste By Using Some Bacterial Strains

    International Nuclear Information System (INIS)

    INAS ISMAIL MAHMOUD RAAFAT

    2015-01-01

    The main study focused on separation of chitin from crustacean waste (shrimp shell) using some proteolytic bacterial isolates. After that, chitosan was obtained by deactylation and its characteristics were studied using some characterizing tools. The produced chitosan was degraded to different molecular weights and evaluated as an antibacterial agent. Seventy bacterial isolates were obtained from different sources (soil, plant roots and shrimp shell waste) and tested for their ability to produce proteolytic enzymes. One isolate was selected, due its high proteolytic activity and ability to grow using shrimp as carbon and nitrogen source on shrimp shell agar medium and identified as Bacillus subtilis NA12 by 16S-rRNA gene sequences with a high degree of similarity (99 %) as a gene bank database. Factors affecting deproteinization (DP) and demineralization (DM) efficiency of shrimp shell waste (SSW) (carbon source and its optimal concentration, shrimp shell waste concentration, inoculum size and fermentation time) were studied. The most efficient DP (92.40 %) and DM (81.37 %) of SSW by B. subtilis NA12 were sucrose 10 % (w/v) and inoculum size 15 % (v/v 35 x 108 CFU/ml ) to ferment shrimp shell waste 5 % (w/v) for 6 days of fermentation time. The effect of γ-irradiation on the performance of selected bacterial strain was studied to maximize chitin yield. Box-Behnken design using response surface methodology was employed to establish the relationship between the previous variables, implied that the model was highly significant. It was found that a sucrose concentration of 5 % (w/v), SSW of 12.5 % (w/v), inoculum size of 10 % (v/v) and fermentation time of 7 days; had a predicted value of DP of 97.65 % whereas the actual experiment gave 96.37 %. The predicted value of DM was 82.94 % whereas the actual experiment gave 82.19 %. Chitosan polymer was successfully prepared by the deacetylation reaction from fermented shrimp shell waste (SSW) by Bacillus subtilis NA12

  12. [Genetic diversity of extraintestinal Escherichia coli strains producers of beta-lactamases TEM, SHV and CTX-M associated with healthcare].

    Science.gov (United States)

    Varela, Yasmin; Millán, Beatriz; Araque, María

    2017-06-01

    There are few reports from Venezuela describing the genetic basis that sustains the pathogenic potential and phylogenetics of Escherichia coli extraintestinal strains isolated in health care units. To establish the genetic diversity of extraintestinal E. coli strains producers of betalactamases TEM, SHV and CTX-M associated with healthcare. We studied a collection of 12 strains of extraintestinal E. coli with diminished sensitivity to broad-spectrum cephalosporins. Antimicrobial susceptibility was determined by minimum inhibitory concentration. We determined the phylogenetic groups, virulence factors and genes encoding antimicrobial resistance using PCR, and clonal characterization by repetitive element palindromic-PCR rep-PCR. All strains showed resistance to cephalosporins and joint resistance to quinolones and aminoglycosides. The phylogenetic distribution showed that the A and B1 groups were the most frequent, followed by D and B2. We found all the virulence factors analyzed in the B2 group, and fimH gene was the most frequent among them. We found blaCTX-M in all strains,with a higher prevalence of blaCTX-M-8; two of these strains showed coproduction of blaCTX-M-9 and were genetically identified as blaCTXM-65 and blaCTX-M-147 by sequencing. The strains under study showed genetic diversity, hosting a variety of virulence genes, as well as antimicrobial resistance with no particular phylogroup prevalence. This is the first report of blaCTX-M alleles in Venezuela and in the world associated to non-genetically related strains isolated in health care units, a situation that deserves attention, as well as the rationalization of antimicrobials use.

  13. Profile of Shiga toxin-producing Escherichia coli strains isolated from dogs and cats and genetic relationships with isolates from cattle, meat and humans.

    Science.gov (United States)

    Bentancor, A; Rumi, M V; Carbonari, C; Gerhardt, E; Larzábal, M; Vilte, D A; Pistone-Creydt, V; Chinen, I; Ibarra, C; Cataldi, A; Mercado, E C

    2012-05-04

    Pets can be reservoirs of Shiga toxin-producing Escherichia coli (STEC) strains. The aim of this study was to examine nine strains belonging to several serotypes (O91:H21, O91:H16, O178:H19, O8:H19, O22:H8, O22:HNT, ONT:H8), previously recovered from cats or dogs. To this end, we assessed a set of additional virulence genes (stx(2) subtype, subAB, ehxA, eae and saa), cytotoxic activity, and genetic relationships with strains isolated from cattle, meat and humans using pulsed-field gel electrophoresis (PFGE). Most of the isolates carried the stx(2) and/or stx(2vh-b) sequences, while only the O91:H21 isolate presented the mucus-activatable stx(2d) variant, as confirmed by sequencing the genes of subunits A and B. All the strains showed cytotoxic activity in cultured cells. One of the two O178:H19, selected for its high level of cytotoxicity in Vero cells, showed the ability to cause functional alterations in the human colon mucosa in vitro. None of the strains possessed the subAB, eae or saa genes and only the strains belonging to serotype O8:H19 carried the ehxA gene. The isolates shared 90-100% similarity by PFGE to epidemiologically unrelated strains of the corresponding serotypes recovered from cattle, meat or humans. Our results demonstrate that dogs and cats may have a role in the infection of humans by STEC, probably serving as a vehicle for bovine strains in the cycle of human infection, and thus emphasize the health risks for owners and their families. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Comparative evaluation of the Ridascreen Verotoxin enzyme immunoassay for detection of Shiga-toxin producing strains of Escherichia coli (STEC) from food and other sources.

    Science.gov (United States)

    Beutin, L; Steinrück, H; Krause, G; Steege, K; Haby, S; Hultsch, G; Appel, B

    2007-03-01

    To evaluate the suitability of the commercially distributed Ridascreen Verotoxin enzyme immunoassay (EIA) for detection of known genetic types of the Vero (Shiga) toxins 1 (Stx1) and 2 (Stx2) families and to determine its relative sensitivity and specificity. The Ridascreen-EIA was compared with the Vero cell assay, a P(1)-glycoprotein receptor EIA and with stx gene-specific PCs for detection of Stx with 43 Shiga toxin-producing strains of Escherichia coli (STEC) reference strains and with 241 test strains. The Ridascreen-EIA detects strains producing Stx1 and variants Stx1c and Stx1d, as well as Stx2 and variants Stx2d1, Stx2d2, Stx2e, Stx2d, Stx2-O118 (Stx2d-ount), Stx2-NV206, Stx2f and Stx2g. The assay showed a relative sensitivity of 95.7% and a relative specificity of 98.7%. Some of the Stx2-O118-, Stx2e- and Stx2g-producing STEC were not detected with the Ridascreen-EIA probably because of low amount of toxin produced by these strains. The Ridascreen-EIA is able to detect all known types of Stx and is applicable for routine screening of bacterial isolates owing to its high specificity. It is less applicable for testing samples where low amounts of Stx are expected, such as mixed cultures and certain Stx2 variants. This study presents a first comprehensive evaluation of the Ridascreen-EIA, a rapid standardized STEC screening test for routine diagnostic laboratories. Data are presented on the type of the spectrum of Stx that are detected with this immunoassay and its advantages and limits for practical use.

  15. Breeding of Coenzyme Q10 Produced Strain by Low-Energy Ion Implantation and Optimization of Coenzyme Q10 Fermentation

    International Nuclear Information System (INIS)

    Xu Dejun; Zheng Zhiming; Wang Peng; Wang Li; Yuan Hang; Yu Zengliang

    2008-01-01

    In order to increase the production efficiency of coenzyme Q 10 , the original strain Agrobacterium tumefaciens ATCC 4452 was mutated by means of Nitrogen ions implantation. A mutant strain, ATX 12, with high contents of coenzyme Q 10 was selected. Subsequently, the conditions such as carbohydrate concentration, nitrogen source concentration, inoculum's size, seed age, aeration and temperature which might affect the production of CoQ 10 were investigated in detail. Under optimal conditions, the maximum concentration of the intracellular CoQ 10 reached 200.3 mg/L after 80 h fed-batch fermentation, about 245% increasing in CoQ 10 production after ion implantation, compared to the original strain. (ion beam bioengineering)

  16. The Prevalence of Esbl-Producing Strains of E.coli, Isolated from Calves with Colibacilosis - Preliminary Remarks

    Directory of Open Access Journals (Sweden)

    Andreea Paula COZMA

    2017-05-01

    The studies that were previously conducted on the dairy farms have pointed out that the young calves rapidly acquire bacterial strains resistant to antibiotics that are often ESBL strains (Hordijk et al., 2013. The prevalence obtained by us, as well as an insufficient quantity of information concerning the antimicrobial resistance on this segment of species of animals used for the human consumption, support conducting a more thorough study, as well as the identification of ESBL resistance genes, but also of the plasmids that encode the transmission of these genes.

  17. Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells.

    Science.gov (United States)

    Jia, Fang-Fang; Zhang, Lu-Ji; Pang, Xue-Hui; Gu, Xin-Xi; Abdelazez, Amro; Liang, Yu; Sun, Si-Rui; Meng, Xiang-Chen

    2017-10-01

    Lactobacillus plantarum KLDS1.0391 is a probiotic strain isolated from the traditional fermented dairy products and identified to produce bacteriocin against Gram-positive and Gram-negative bacteria. Previous studies showed that the strain has a high resistance to gastrointestinal stress and has a high adhesion ability to the intestinal epithelial cells (Caco-2). We reported the entire genome sequence of this strain, which contains a circular 2,886,607-bp chromosome and three circular plasmids. Genes, which are related to the biosynthesis of bacteriocins, the stress resistance to gastrointestinal tract environment and adhesive performance, were identified. Whole genome sequence of Lactobacillus plantarum KLDS1.0391 will be helpful for its applications in food industry. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Linking Genotype and Phenotype of Saccharomyces cerevisiae Strains Reveals Metabolic Engineering Targets and Leads to Triterpene Hyper-Producers

    DEFF Research Database (Denmark)

    Madsen, Karina Marie; Udatha, Gupta D. B. R. K.; Semba, Saori

    2011-01-01

    with the S288C strain, we implemented a strategy for the construction of a beta-amyrin production platform. The genes Erg8, Erg9 and HFA1 contained non-silent SNPs that were computationally analyzed to evaluate the changes that cause in the respective protein structures. Subsequently, Erg8, Erg9 and HFA1...

  19. Analysing the dhaT gene in Colombian Clostridium sp. (Clostridia 1,3-propanediol-producing strains

    Directory of Open Access Journals (Sweden)

    Diana Milena Quilaguy-Ayure

    2010-04-01

    Full Text Available To analyze the dhaT gene, one of the genes responsible for the 1,3-propanediol (1,3-PD production, in two native Clostridiumstrains. Materials and methods: The dhaT gene was amplified by Polimerase Chain Reaction with specific primers designed fromClostridium butyricum VPI1718 operon. Bioinformatics tools like BLASTN, ORF finder, BLASTP and ClustalW were used to determinethe identity of the sequence and to assign a function. Results: DNA amplification products were obtained from Colombian Clostridium sp.native strains (IBUN 13A and IBUN 158B and the Clostridium butyricum DSM 2478 strain, which were sequenced. According to thebioinformatics analysis of the above sequences, a high degree of similarity was found with the dhaT gene of different bacterial species. Thehighest percentage of identity was obtained with the Clostridium butyricum VPI 1718 strain. Conclusion: knowledge of the physicalstructure of the 1,3-PD operon in native strains opens the way for developing genetic and metabolic engineering strategies for improvingprocesses productivity.

  20. Purification and Properties of an Insecticidal Metalloprotease Produced by Photorhabdus luminescens Strain 0805-P5G, the Entomopathogenic Nematode Symbiont

    Directory of Open Access Journals (Sweden)

    Feng-Chia Hsieh

    2012-12-01

    Full Text Available A total of 13 Photorhabdus luminescens strains were screened for proteolytic activity. The P. luminescens strain 0805-P5G had the highest activity on both skim milk and gelatin plates. The protease was purified to electrophoretical homogeneity by using a two-step column chromatographic procedure. It had a molecular weight of 51.8 kDa, as determined by MALDI-TOF mass spectrometry. The optimum pH, temperature, as well as pH and thermal stabilities were 8, 60 °C, 5–10, and 14–60 °C, respectively. It was completely inhibited by EDTA and 1,10-phenanthroline. Bioassay of the purified protease against Galleria mellonella by injection showed high insecticidal activity. The protease also showed high oral toxicity to the diamondback moth (Plutella xylostella of a Taiwan field-collected strain, but low toxicity to an American strain. To our knowledge, this is the first report to demonstrate that the purified protease of P. luminescens has direct toxicity to P. xylostella and biopesticide potentiality.

  1. Isolation of a novel alginate lyase-producing Bacillus litoralis strain and its potential to ferment Sargassum horneri for biofertilizer.

    Science.gov (United States)

    Wang, Mingpeng; Chen, Lei; Liu, Zhengyi; Zhang, Zhaojie; Qin, Song; Yan, Peisheng

    2016-12-01

    Algae have long been used to augment plant productivity through their beneficial effects. Alginate oligosaccharide is believed to be one of the important components to enhance growth and crop yield. In this study, we isolated and characterized a Bacillus litoralis strain, named Bacillus M3, from decayed kelps. We further demonstrated that the M3 strain could secrete alginate lyase to degrade alginate. The crude enzyme exhibited the highest activity (33.74 U/mg) at pH 7.0 and 50°C. The M3 strain was also able to ferment the brown alga Sargassum horneri. Fermentation results revealed that a fermentation period of 8-12 hr was the best harvest time with the highest level of alginate oligosaccharides. Plant growth assay showed that the seaweed fermentation extract had an obvious promotion effect on root and seedling growth of Lycopersicon eseulentum L. Our results suggest that fermentation extract of Sargassum horneri by the novel strain of Bacillus litoralis M3 has significant development potential for biofertilizer production and agriculture application. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  2. Characterization of hydrocarbon-degrading and biosurfactant-producing Pseudomonas sp. P-1 strain as a potential tool for bioremediation of petroleum-contaminated soil.

    Science.gov (United States)

    Pacwa-Płociniczak, Magdalena; Płaza, Grażyna Anna; Poliwoda, Anna; Piotrowska-Seget, Zofia

    2014-01-01

    The Pseudomonas sp. P-1 strain, isolated from heavily petroleum hydrocarbon-contaminated soil, was investigated for its capability to degrade hydrocarbons and produce a biosurfactant. The strain degraded crude oil, fractions A5 and P3 of crude oil, and hexadecane (27, 39, 27 and 13% of hydrocarbons added to culture medium were degraded, respectively) but had no ability to degrade phenanthrene. Additionally, the presence of gene-encoding enzymes responsible for the degradation of alkanes and naphthalene in the genome of the P-1 strain was reported. Positive results of blood agar and methylene blue agar tests, as well as the presence of gene rhl, involved in the biosynthesis of rhamnolipid, confirmed the ability of P-1 for synthesis of glycolipid biosurfactant. 1H and 13C nuclear magnetic resonance, Fourier transform infrared spectrum and mass spectrum analyses indicated that the extracted biosurfactant was affiliated with rhamnolipid. The results of this study indicate that the P-1 and/or biosurfactant produced by this strain have the potential to be used in bioremediation of hydrocarbon-contaminated soils.

  3. Genomic and proteomic characterization of bacteriocin-producing Leuconostoc mesenteroides strains isolated from raw camel milk in two southwest Algerian arid zones.

    Science.gov (United States)

    Benmechernene, Zineb; Fernández-No, Inmaculada; Quintela-Baluja, Marcos; Böhme, Karola; Kihal, Mebrouk; Calo-Mata, Pilar; Barros-Velázquez, Jorge

    2014-01-01

    Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocin Leuconostoc strains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology with Leuconostoc mesenteroides was observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the species L. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information of L. mesenteroides than phylogenetic analysis. Accordingly, phyloproteomic analysis grouped L. mesenteroides strains into different subbranches, while all L. mesenteroides isolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.

  4. Genomic and Proteomic Characterization of Bacteriocin-Producing Leuconostoc mesenteroides Strains Isolated from Raw Camel Milk in Two Southwest Algerian Arid Zones

    Directory of Open Access Journals (Sweden)

    Zineb Benmechernene

    2014-01-01

    Full Text Available Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocin Leuconostoc strains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology with Leuconostoc mesenteroides was observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the species L. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information of L. mesenteroides than phylogenetic analysis. Accordingly, phyloproteomic analysis grouped L. mesenteroides strains into different subbranches, while all L. mesenteroides isolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.

  5. Effect of γ-Aminobutyric Acid-producing Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress

    Directory of Open Access Journals (Sweden)

    Y. Z. Zhu

    2015-07-01

    Full Text Available Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164 at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i 0 mg/kg, ii 25 mg/kg, iii 50 mg/kg, and iv 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05 by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05 than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009 and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to

  6. Effect of γ-Aminobutyric Acid-producing Lactobacillus Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress.

    Science.gov (United States)

    Zhu, Y Z; Cheng, J L; Ren, M; Yin, L; Piao, X S

    2015-07-01

    Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (pGABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (plevel was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

  7. Identification of human-pathogenic strains of Shiga toxin-producing Escherichia coli from food by a combination of serotyping and molecular typing of Shiga toxin genes.

    Science.gov (United States)

    Beutin, Lothar; Miko, Angelika; Krause, Gladys; Pries, Karin; Haby, Sabine; Steege, Katja; Albrecht, Nadine

    2007-08-01

    We examined 219 Shiga toxin-producing Escherichia coli (STEC) strains from meat, milk, and cheese samples collected in Germany between 2005 and 2006. All strains were investigated for their serotypes and for genetic variants of Shiga toxins 1 and 2 (Stx1 and Stx2). stx(1) or variant genes were detected in 88 (40.2%) strains and stx(2) and variants in 177 (80.8%) strains. Typing of stx genes was performed by stx-specific PCRs and by analysis of restriction fragment length polymorphisms (RFLP) of PCR products. Major genotypes of the Stx1 (stx(1), stx(1c), and stx(1d)) and the Stx2 (stx(2), stx(2d), stx(2-O118), stx(2e), and stx(2g)) families were detected, and multiple types of stx genes coexisted frequently in STEC strains. Only 1.8% of the STEC strains from food belonged to the classical enterohemorrhagic E. coli (EHEC) types O26:H11, O103:H2, and O157:H7, and only 5.0% of the STEC strains from food were positive for the eae gene, which is a virulence trait of classical EHEC. In contrast, 95 (43.4%) of the food-borne STEC strains carried stx(2) and/or mucus-activatable stx(2d) genes, an indicator for potential high virulence of STEC for humans. Most of these strains belonged to serotypes associated with severe illness in humans, such as O22:H8, O91:H21, O113:H21, O174:H2, and O174:H21. stx(2) and stx(2d) STEC strains were found frequently in milk and beef products. Other stx types were associated more frequently with pork (stx(2e)), lamb, and wildlife meat (stx(1c)). The combination of serotyping and stx genotyping was found useful for identification and for assignment of food-borne STEC to groups with potential lower and higher levels of virulence for humans.

  8. Draft Genome Sequence of a Cellulase-Producing Psychrotrophic Paenibacillus Strain, IHB B 3415, Isolated from the Cold Environment of the Western Himalayas, India.

    Science.gov (United States)

    Dhar, Hena; Swarnkar, Mohit Kumar; Gulati, Arvind; Singh, Anil Kumar; Kasana, Ramesh Chand

    2015-02-19

    Paenibacillus sp. strain IHB B 3415 is a cellulase-producing psychrotrophic bacterium isolated from a soil sample from the cold deserts of Himachal Pradesh, India. Here, we report an 8.44-Mb assembly of its genome sequence with a G+C content of 50.77%. The data presented here will provide insights into the mechanisms of cellulose degradation at low temperature. Copyright © 2015 Dhar et al.

  9. Quantitative analysis of the lactic acid and acetaldehyde produced by Streptococcus thermophilus and Lactobacillus bulgaricus strains isolated from traditional Turkish yogurts using HPLC.

    Science.gov (United States)

    Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I

    2015-03-01

    The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the

  10. Technological characterization and survival of the exopolysaccharide-producing strain Lactobacillus delbrueckii subsp. lactis 193 and its bile-resistant derivative 193+ in simulated gastric and intestinal juices.

    Science.gov (United States)

    Burns, Patricia; Vinderola, Gabriel; Reinheimer, Jorge; Cuesta, Isabel; de Los Reyes-Gavilán, Clara G; Ruas-Madiedo, Patricia

    2011-08-01

    The capacity of lactic acid bacteria to produce exopolysaccharides (EPS) conferring microorganisms a ropy phenotype could be an interesting feature from a technological point of view. Progressive adaptation to bile salts might render some lactobacilli able to overcome physiological gut barriers but could also modify functional properties of the strain, including the production of EPS. In this work some technological properties and the survival ability in simulated gastrointestinal conditions of Lactobacillus delbrueckii subsp. lactis 193, and Lb. delbrueckii subsp. lactis 193+, a strain with stable bile-resistant phenotype derived thereof, were characterized in milk in order to know whether the acquisition of resistance to bile could modify some characteristics of the microorganism. Both strains were able to grow and acidify milk similarly; however the production of ethanol increased at the expense of the aroma compound acetaldehyde in milk fermented by the strain 193+, with respect to milk fermented by the strain 193. Both microorganisms produced a heteropolysaccharide composed of glucose and galactose, and were able to increase the viscosity of fermented milks. In spite of the higher production yield of EPS by the bile-resistant strain 193+, it displayed a lower ability to increase viscosity than Lb. delbrueckii subsp. lactis 193. Milk increased survival in simulated gastric juice; the presence of bile improved adhesion to the intestinal cell line HT29-MTX in both strains. However, the acquisition of a stable resistance phenotype did not improve survival in simulated gastric and intestinal conditions or the adhesion to the intestinal cell line HT29-MTX. Thus, Lb. delbrueckii subsp. lactis 193 presents suitable technological properties for the manufacture of fermented dairy products; the acquisition of a stable bile-resistant phenotype modified some properties of the microorganism. This suggests that the possible use of bile-resistant derivative strains should be

  11. Screening and characterization of alkaline protease produced by a pink pigmented facultative methylotrophic (PPFM strain, MSF 46

    Directory of Open Access Journals (Sweden)

    Shanmugam Jayashree

    2014-12-01

    Full Text Available Among the various bacterial isolates, the strain MSF 46 isolated from thorn forest soil samples, Tamil Nadu, India, was screened and characterized for its proteolytic activity. While the 16S rRNA sequencing and biochemical characterization revealed that the strain closely resembles Methylobacterium sp., methylotrophy of the strain was confirmed by the sequence homology of mxaF gene with other relative Methylobacterium sp. The alkaline protease was purified to homogeneity using DEAE cellulose ion exchange chromatography, with a 5.2-fold increase in specific activity and 34% recovery. The apparent molecular weight of the enzyme was determined as 40 kDa by SDS–PAGE study. The pH and temperature optima were 9.0 and 50 °C respectively with maximum protease activity of 1164 U/ml. Protease of MSF 46 was active in a broad pH range 7.0–11.0 with a maximum at pH 8.5 and exhibited thermostability at 50 °C. The enzyme activity was inhibited by PMSF but showed stability with Tween 20, Triton X-100 and hydrogen peroxide. Nearly 30% reduction in enzyme activity was observed in the presence of EDTA and DTT. The enzyme was effective in hydrolyzing gelatin, skimmed milk and blood clots and exhibited the potency for dehairing of goat skin and removing blood stain from cotton fabric. Significant morphological changes were observed under scanning electron microscope between cells grown in normal and casein amended medium. This first detailed report on the production of alkaline protease by a PPFM strain appears promising toward development of protocols for mass production, study of the molecular mechanism and other applications.

  12. Detection and characterization of bacteriocin-producing Lactococcus lactis strains Detecção e caracterização de Lactococcus lactis produtores de bacteriocinas

    Directory of Open Access Journals (Sweden)

    Izildinha Moreno

    1999-04-01

    Full Text Available One hundred sixty seven strains of Lactococcus lactis were screened for bacteriocin production by well diffusion assay of GM17 agar. Fourteen (8.4% produced antimicrobial activity other than organic acids, bacteriophages or hydrogen peroxide. The frequency of bacteriocin production ranged from 2% in L. lactis subsp. cremoris up to 12% in L. lactis subsp. lactis. Antimicrobial activities were not observed in any strain of L. lactis subsp. lactis var. diacetylactis. Among thirteen bacteriocin-producing strains and two nisin-producing strains (L. lactis subsp. lactis ATCC 11454 and L. lactis subsp. lactis CNRZ 150, eight (53% were characterized as lactose-positive (Lac+ and proteinase-negative (Prt-. The bacteriocin-producing cultures were also characterized on the basis of plasmid content. All strains had 2 to 7 plasmids with molecular weights varying from 0.5 to 28.1 Mdal. Four strains (ITAL 435, ITAL 436, ITAL 437 and ITAL 438 showed identical profiles and the other were quite distinct.Um total de 167 linhagens de L. lactis foi selecionado para os testes de produção de bacteriocinas pelo método de difusão em poços em agar GM17. Desse total, 14 (8.4% produziram substâncias inibidoras que não foram associadas com ácidos orgânicos, peróxido de hidrogênio e bacteriófagos. A frequência de produção de bacteriocinas variou de 2% em L. lactis subsp. cremoris a 12% em L. lactis subsp. lactis. Nenhuma das linhagens de L. lactis subsp. lactis var. diacetylactis produziu substâncias inibidoras. De 13 linhagens produtoras de bacteriocinas e duas de nisina (L. lactis subsp. lactis ATCC 11454 e L. lactis subsp. lactis CNRZ 150, 8 (53% foram caracterizadas como lactose-positivas (Lac+ e proteinase-negativas (Prt-. As linhagens produtoras de bacteriocinas também foram caracterizadas no seu conteúdo de plasmídios. Elas apresentaram de 2 a 7 plasmídios, com pesos moleculares aproximados de 0.5 a 28.1 Mdal. Quatro linhagens (ITAL 435, ITAL 436

  13. Mexican unpasteurised fresh cheeses are contaminated with Salmonella spp., non-O157 Shiga toxin producing Escherichia coli and potential uropathogenic E. coli strains: A public health risk.

    Science.gov (United States)

    Guzman-Hernandez, Rosa; Contreras-Rodriguez, Araceli; Hernandez-Velez, Rosa; Perez-Martinez, Iza; Lopez-Merino, Ahide; Zaidi, Mussaret B; Estrada-Garcia, Teresa

    2016-11-21

    Fresh cheeses are a main garnish of Mexican food. Consumption of artisanal fresh cheeses is very common and most of them are made from unpasteurised cow milk. A total of 52 fresh unpasteurised cheeses of five different types were purchased from a variety of suppliers from Tabasco, Mexico. Using the most probable number method, 67% and 63% of samples were positive for faecal coliforms and E. coli, respectively; revealing their low microbiological quality. General hygienic conditions and practices of traditional cheese manufacturers were poor; most establishments had unclean cement floors, all lacked windows and doors screens, and none of the food-handlers wore aprons, surgical masks or bouffant caps. After analysing all E. coli isolates (121 strains) for the presence of 26 virulence genes, results showed that 9 (17%) samples were contaminated with diarrheagenic E. coli strains, 8 harboured non-O157 Shiga toxin producing E. coli (STEC), and one sample contained both STEC and diffusely adherent E. coli strains. All STEC strains carried the stx1 gene. Potential uropathogenic E. coli (UPEC) strains were isolated from 15 (29%) samples; the most frequent gene combination was fimA-agn43. Two samples were contaminated with Salmonella. The results demonstrated that unpasteurised fresh cheeses produced in Tabasco are of poor microbiological quality and may frequently harbour foodborne pathogens. Food safety authorities in Mexico need to conduct more rigorous surveillance of fresh cheeses. Furthermore, simple and inexpensive measures as establishing programs emphasizing good hand milking practices and hygienic manufacturing procedures may have a major effect on improving the microbiological quality of these food items. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Distribution and antimicrobial susceptibility profile of extended-spectrum β-lactamase-producing Proteus mirabilis strains recently isolated in Japan.

    Science.gov (United States)

    Kanayama, Akiko; Kobayashi, Intetsu; Shibuya, Kazutoshi

    2015-02-01

    Here we report on the prevalence of extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis from a nationwide antimicrobial resistance survey in different geographical regions of Japan. A total of 799 P. mirabilis isolates recovered between July 2009 and June 2010 from 314 healthcare facilities were characterised according to ESBL production, source, location and antimicrobial susceptibility pattern. ESBL production was found in 364 (45.6%) of the isolates, among which 354 (97.3%) produced CTX-M-2 group β-lactamases. Of the 349 ESBL-producing isolates in which the inpatient or outpatient status of the source was known, 324 (92.8%) were from inpatients and 25 (7.2%) were from outpatients (Pmirabilis compared with 159/405 (39.3%), 119/209 (56.9%), 42/77 (54.5%) and 20/49 (40.8%), respectively, for isolates from urine, sputum, decubitus ulcer and wound specimens. Among the ESBL-producers, non-susceptibility to ciprofloxacin was found in 74.2% of the ESBL-producing isolates compared with 17.7% of the ESBL-non-producing isolates. These results show that approximately one-half of the P. mirabilis isolates from clinical specimens in Japan are ESBL-producers and that the potential for concomitant fluoroquinolone resistance must also be considered. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  15. Genealogy profiling through strain improvement by using metabolic network analysis: metabolic flux genealogy of several generations of lysine-producing corynebacteria.

    Science.gov (United States)

    Wittmann, Christoph; Heinzle, Elmar

    2002-12-01

    A comprehensive approach of metabolite balancing, (13)C tracer studies, gas chromatography-mass spectrometry, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and isotopomer modeling was applied for comparative metabolic network analysis of a genealogy of five successive generations of lysine-producing Corynebacterium glutamicum. The five strains examined (C. glutamicum ATCC 13032, 13287, 21253, 21526, and 21543) were previously obtained by random mutagenesis and selection. Throughout the genealogy, the lysine yield in batch cultures increased markedly from 1.2 to 24.9% relative to the glucose uptake flux. Strain optimization was accompanied by significant changes in intracellular flux distributions. The relative pentose phosphate pathway (PPP) flux successively increased, clearly corresponding to the product yield. Moreover, the anaplerotic net flux increased almost twofold as a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes to cover the increased demand for lysine formation; thus, the overall increase was a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes. The relative flux through isocitrate dehydrogenase dropped from 82.7% in the wild type to 59.9% in the lysine-producing mutants. In contrast to the NADPH demand, which increased from 109 to 172% due to the increasing lysine yield, the overall NADPH supply remained constant between 185 and 196%, resulting in a decrease in the apparent NADPH excess through strain optimization. Extrapolated to industrial lysine producers, the NADPH supply might become a limiting factor. The relative contributions of PPP and the tricarboxylic acid cycle to NADPH generation changed markedly, indicating that C. glutamicum is able to maintain a constant supply of NADPH under completely different flux conditions. Statistical analysis by a Monte Carlo approach revealed high precision for the estimated fluxes, underlining the

  16. Identification of point mutations in clinical Staphylococcus aureus strains that produce small-colony variants auxotrophic for menadione.

    Science.gov (United States)

    Dean, Melissa A; Olsen, Randall J; Long, S Wesley; Rosato, Adriana E; Musser, James M

    2014-04-01

    Staphylococcus aureus small-colony variants (SCVs) are implicated in chronic and relapsing infections that are difficult to diagnose and treat. Despite many years of study, the underlying molecular mechanisms and virulence effect of the small-colony phenotype remain incompletely understood. We sequenced the genomes of five S. aureus SCV strains recovered from human patients and discovered previously unidentified nonsynonymous point mutations in three genes encoding proteins in the menadione biosynthesis pathway. Analysis of genetic revertants and complementation with wild-type alleles confirmed that these mutations caused the SCV phenotype and decreased virulence for mice.

  17. Nonbioluminescent strains of Photobacterium phosphoreum produce the cell-to-cell communication signal N-(3-Hydroxyoctanoyl)homoserine lactone

    DEFF Research Database (Denmark)

    Flodgaard, Lars; Dalgaard, Paw; Andersen, Jens Bo

    2005-01-01

    Bioluminescence is a common phenotype in marine bacteria, such As Vibrio and Photobacterium species, and can be quorum regulated by N-acylated homoserine lactones (AHLs). We extracted a molecule that induced a bacterial AHL monitor (Agrobacterium tumefaciens NT1 [pZLR4]) from packed cod fillets......) and shape to N-(3-hydroxyoctanoyl)homoserine lactone, and the presence of this molecule in culture supernatants from a nonbioluminescent strain of P. phosphoreum was confirmed by high-performance liquid chromatography-positive electrospray high-resolution mass spectrometry. Bioluminescence (in a non...

  18. Induction of Aspergillus oryzae mutant strains producing increased levels of α-amylase by gamma-irradiation

    International Nuclear Information System (INIS)

    Ito, Hitoshi; Nessa, Azizun

    1996-01-01

    Spores of Aspergillus oryzae IAM 2630 were suspended in 0.067 m phosphate buffer and irradiated with gamma rays. Spores were incubated for 7 days and colony mutants counted by observing colour change compared to normal colours. α-amylase activities of the normal and mutant colonies were assayed. DNA assay of the spores was also carried out, after culture on different plating media. Enzyme production increased 2-5 times with increasing radiation dose. Increased spore size and DNA content was also observed in mutant strains with higher enzyme production suggesting that enzyme production is genetically controlled. Ultraviolet radiation did not appear to induce higher frequency of mutation. (UK)

  19. Induction of Aspergillus oryzae mutant strains producing increased levels of {alpha}-amylase by gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hitoshi; Nessa, Azizun [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-12-01

    Spores of Aspergillus oryzae IAM 2630 were suspended in 0.067 m phosphate buffer and irradiated with gamma rays. Spores were incubated for 7 days and colony mutants counted by observing colour change compared to normal colours. {alpha}-amylase activities of the normal and mutant colonies were assayed. DNA assay of the spores was also carried out, after culture on different plating media. Enzyme production increased 2-5 times with increasing radiation dose. Increased spore size and DNA content was also observed in mutant strains with higher enzyme production suggesting that enzyme production is genetically controlled. Ultraviolet radiation did not appear to induce higher frequency of mutation. (UK).

  20. Supplementary Material for: In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

    KAUST Repository

    Motwalli, Olaa Amin; Essack, Magbubah; Jankovic, Boris R.; Ji, Boyang; Liu, Xinyao; Ansari, Hifzur; Hoehndorf, Robert; Gao, Xin; Arold, Stefan T.; Mineta, Katsuhiko; Archer, John; Gojobori, Takashi; Mijakovic, Ivan; Bajic, Vladimir B.

    2017-01-01

    Abstract Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors

  1. Characterization and properties of biosurfactants produced by a newly isolated strain Bacillus methylotrophicus DCS1 and their applications in enhancing solubility of hydrocarbon.

    Science.gov (United States)

    Jemil, Nawel; Ben Ayed, Hanen; Hmidet, Noomen; Nasri, Moncef

    2016-11-01

    Six biosurfactant-producing bacteria were isolated from hydrocarbon contaminated soils in Sfax, Tunisia. Isolates were screened for biosurfactant production by different conventional methods including hemolytic activity, surface tension reduction, drop-collapsing and oil displacement tests. All these screening tests show that all the isolates behave differently. Among the isolated bacteria, DCS1 strain was selected for further studies based on its highest activities and it was identified as Bacillus methylotrophicus DCS1. This strain was found to be a potent producer of biosurfactant when cultivated in mineral-salts medium supplemented with diesel oil (2 %, v/v) as a sole carbon source. Physicochemical properties and stability of biosurfactants synthesized by B. methylotrophicus DCS1 were investigated. The produced biosurfactants DCS1, from Landy medium, possess high surface activity that could lower the surface tension of water to a value of 31 from 72 mN m(-1) and have a critical micelle concentration (CMC) of 100 mg L(-1). Compared with SDS and Tween 80, biosurfactants showed excellent emulsification activities against different hydrocarbon substrates and high solubilization efficiency towards diesel oil. Biosurfactants DCS1 showed good stability in a wide range of temperature, pH and salinity. These results suggested that biosurfactants produced by B. methylotrophicus DCS1 could be an alternative to chemically synthesized surfactants for use in bioremediation processes to enhance the solubility of hydrophobic compounds.

  2. Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation

    International Nuclear Information System (INIS)

    Blanc, P.L.; Tuveson, R.W.; Sargent, M.L.

    1976-01-01

    Suspensions of Neurospora crassa conidia were inactivated by blacklight (BL) radiation (300 to 425 nm) in the absence of exogenous photosensitizing compounds. Carotenoid-containing wild-type conidia were less sensitive to BL radiation than albino conidia, showing a dose enhancement factor (DEF) of 1.2 for dose levels resulting in less than 10 percent survival. The same strains were about equally sensitive to shortwave ultraviolet (uv) inactivation. The kinetics of BL inactivation are similar to those of photodynamic inactivation by visible light in the presence of a photosensitizing dye (methylene blue). Only limited inactivation by visible light in the absence of exogenous photosensitizers was observed. BL and UV inactivations are probably caused by different mechanisms since wild-type conidia are only slightly more resistant to BL radiation (DEF = 1.2 at 1.0 percent survival) than are conidia from a uv-sensitive strain (upr-1, uvs-3). The BL-induced lethal lesions are probably not cyclobutyl pyrimidine dimers since BL-inactivated Haemophilus influenzae transforming deoxyribonucleic acid is not photoreactivated by N. crassa wild-type enzyme extracts, whereas uv-inactivated transforming deoxyribonucleic acid is photoreactivable with this treatment

  3. Cloning and Characterization of a Unique Cytotoxic Protein Parasporin-5 Produced by Bacillus thuringiensis A1100 Strain

    Directory of Open Access Journals (Sweden)

    Keisuke Ekino

    2014-06-01

    Full Text Available Parasporin is the cytocidal protein present in the parasporal inclusion of the non-insecticidal Bacillus thuringiensis strains, which has no hemolytic activity but has cytocidal activities, preferentially killing cancer cells. In this study, we characterized a cytocidal protein that belongs to this category, which was designated parasporin-5 (PS5. PS5 was purified from B. thuringiensis serovar tohokuensis strain A1100 based on its cytocidal activity against human leukemic T cells (MOLT-4. The 50% effective concentration (EC50 of PS5 to MOLT-4 cells was approximately 0.075 μg/mL. PS5 was expressed as a 33.8-kDa inactive precursor protein and exhibited cytocidal activity only when degraded by protease at the C-terminal into smaller molecules of 29.8 kDa. Although PS5 showed no significant homology with other known parasporins, a Position Specific Iterative-Basic Local Alignment Search Tool (PSI-BLAST search revealed that the protein showed slight homology to, not only some B. thuringiensis Cry toxins, but also to aerolysin-type β-pore-forming toxins (β-PFTs. The recombinant PS5 protein could be obtained as an active protein only when it was expressed in a precursor followed by processing with proteinase K. The cytotoxic activities of the protein against various mammalian cell lines were evaluated. PS5 showed strong cytocidal activity to seven of 18 mammalian cell lines tested, and low to no cytotoxicity to the others.

  4. A guinea pig strain with recessive heredity of deafness, producing normal-hearing heterozygotes with resistance to noise trauma.

    Science.gov (United States)

    Skjönsberg, Asa; Herrlin, Petra; Duan, Maoli; Johnson, Ann-Christin; Ulfendahl, Mats

    2005-01-01

    A new strain of waltzing guinea pigs arose spontaneously in a guinea pig breeding facility in Germany in 1996. In addition to obvious vestibular dysfunction, the waltzing animals appear deaf already at birth. Histological analysis revealed that the waltzers lack an open scala media due to the collapse of Reissner's membrane onto the surface of the hearing organ. Subsequent breeding has shown that this strain has a recessive mode of inheritance. The homozygotes are deaf and display a waltzing behaviour throughout their lives while the heterozygotes show no significant signs of inner ear injury despite being carriers of this specific mutated gene of hearing impairment. However, the heterozygous animals offer the opportunity to study how hereditary factors interact with auditory stress. In the present study, the susceptibility of the carriers to noise was investigated. Auditory brainstem responses were obtained prior to and after noise exposure (4 kHz, 110 dB, 6 h). The carriers were significantly less affected by the noise as compared to control animals. This difference was still significant at 4 weeks following noise exposure. It is suggested that the heterozygous animals have an endogenous resistance to auditory stress. Copyright (c) 2005 S. Karger AG, Basel.

  5. Sexual reproduction and mating-type–mediated strain development in the penicillin-producing fungus Penicillium chrysogenum

    Science.gov (United States)

    Böhm, Julia; Hoff, Birgit; O’Gorman, Céline M.; Wolfers, Simon; Klix, Volker; Binger, Danielle; Zadra, Ivo; Kürnsteiner, Hubert; Pöggeler, Stefanie; Dyer, Paul S.; Kück, Ulrich

    2013-01-01

    Penicillium chrysogenum is a filamentous fungus of major medical and historical importance, being the original and present-day industrial source of the antibiotic penicillin. The species has been considered asexual for more than 100 y, and despite concerted efforts, it has not been possible to induce sexual reproduction, which has prevented sexual crosses being used for strain improvement. However, using knowledge of mating-type (MAT) gene organization, we now describe conditions under which a sexual cycle can be induced leading to production of meiotic ascospores. Evidence of recombination was obtained using both molecular and phenotypic markers. The identified heterothallic sexual cycle was used for strain development purposes, generating offspring with novel combinations of traits relevant to penicillin production. Furthermore, the MAT1-1–1 mating-type gene, known primarily for a role in governing sexual identity, was also found to control transcription of a wide range of genes with biotechnological relevance including those regulating penicillin production, hyphal morphology, and conidial formation. These discoveries of a sexual cycle and MAT gene function are likely to be of broad relevance for manipulation of other asexual fungi of economic importance. PMID:23307807

  6. Sexual reproduction and mating-type-mediated strain development in the penicillin-producing fungus Penicillium chrysogenum.

    Science.gov (United States)

    Böhm, Julia; Hoff, Birgit; O'Gorman, Céline M; Wolfers, Simon; Klix, Volker; Binger, Danielle; Zadra, Ivo; Kürnsteiner, Hubert; Pöggeler, Stefanie; Dyer, Paul S; Kück, Ulrich

    2013-01-22

    Penicillium chrysogenum is a filamentous fungus of major medical and historical importance, being the original and present-day industrial source of the antibiotic penicillin. The species has been considered asexual for more than 100 y, and despite concerted efforts, it has not been possible to induce sexual reproduction, which has prevented sexual crosses being used for strain improvement. However, using knowledge of mating-type (MAT) gene organization, we now describe conditions under which a sexual cycle can be induced leading to production of meiotic ascospores. Evidence of recombination was obtained using both molecular and phenotypic markers. The identified heterothallic sexual cycle was used for strain development purposes, generating offspring with novel combinations of traits relevant to penicillin production. Furthermore, the MAT1-1-1 mating-type gene, known primarily for a role in governing sexual identity, was also found to control transcription of a wide range of genes with biotechnological relevance including those regulating penicillin production, hyphal morphology, and conidial formation. These discoveries of a sexual cycle and MAT gene function are likely to be of broad relevance for manipulation of other asexual fungi of economic importance.

  7. Unusual Δ7,12,19 C35:3 Alkenone Produced by the Mutant Emiliania huxleyi strain CCMP2758 in Culture

    Science.gov (United States)

    Zheng, Y.; Huang, Y.; Zhang, Y.; Dillon, J. T.

    2015-12-01

    Alkenones with chain length ranging from C37 to C40 are highly specific biomarkers for certain haptophyte algae in ocean and lake sediments and have been widely used for paleoclimate studies. Short chain alkenones (e.g., C35 and C36) have been found in environmental and culture samples but the origin and structures of these compounds are not fully understood. The benchmark marine alkenone producer, Emiliania huxleyi CCMP2758 strain (the mutant of strain CCMP1742, NEPCC55a) was reported to make 35:2 alkenone when cultured at 15 °C (Prahl et al., 2006). Here we show, when this strain is cultured at lower temperatures (e.g., 4°C), CCMP2758 produces large amount of 35:3 alkenone with unusual double bond positions of Δ7,12,19. We determined the double bond positions of the C35:3 methyl ketonee based on GC-MS analysis of cyclobutylimine derivatives and dimethyl disulfide derivatives respectively, and provide the first temperature calibrations based on the unsaturation ratios of C35 alkenones. Previous studies have found 35:2 alkenone with three methylene interruption in the Black Sea sediment, but it is the first time that an alkenone with a mixed three and five methylene interruption is found. The discovery of short chain alkenones with unusual double bond positions may shed new light to alkenone biosynthesis.

  8. Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae

    International Nuclear Information System (INIS)

    Banu, Afreen; Rathod, Vandana; Ranganath, E.

    2011-01-01

    Highlights: → Silver nanoparticle production by using Rhizopus stolonifer. → Antibacterial activity of silver nanoparticles against extended spectrum β-lactamase producing (ESBL) strains of Enterobacteriaceae. → Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. → Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

  9. Effect of gamma radiation on the reduction of Salmonella strains, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli and sensory evaluation of minimally processed spinach (Tetragonia expansa).

    Science.gov (United States)

    Rezende, Ana Carolina B; Igarashi, Maria Crystina; Destro, Maria Teresa; Franco, Bernadette D G M; Landgraf, Mariza

    2014-10-01

    This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

  10. Silver nanoparticle production by Rhizopus stolonifer and its antibacterial activity against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae

    Energy Technology Data Exchange (ETDEWEB)

    Banu, Afreen [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Rathod, Vandana, E-mail: drvandanarathod@rediffmail.com [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India); Ranganath, E. [Department of Microbiology, Gulbarga University, Gulbarga 585106, Karnataka (India)

    2011-09-15

    Highlights: {yields} Silver nanoparticle production by using Rhizopus stolonifer. {yields} Antibacterial activity of silver nanoparticles against extended spectrum {beta}-lactamase producing (ESBL) strains of Enterobacteriaceae. {yields} Synergistic effect of antibiotics with silver nanoparticles towards ESBL-strains. {yields} Characterization of silver nanoparticles made by UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, atomic force microscopy (AFM). -- Abstract: This report focuses on the synthesis of silver nanoparticles using the fungus, Rhizopus stolonifer and its antimicrobial activity. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Characterization of newly synthesized silver nanoparticles was made by UV-visible absorption spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and atomic force microscope (AFM). TEM micrograph revealed the formation of spherical nanoparticles with size ranging between 3 and 20 nm. The biosynthesized silver nanoparticles (AgNPs) showed excellent antibacterial activity against ESBL-strains which includes E. coli, Proteus. sp. and Klebsiella sp.

  11. Anti-bacterial Efficacy of Bacteriocin Produced by Marine Bacillus subtilis Against Clinically Important Extended Spectrum Beta-Lactamase Strains and Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Suresh Mickymaray

    2018-02-01

    Full Text Available Objective: To investigate the anti-bacterial efficacy of bacteriocin produced by Bacillus subtilis SM01 (GenBank accession no: KY612347, a Gram-positive marine bacterium, against Extended Spectrum Beta-Lactamase (ESBL producing Gram-negative pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli, and Gram-positive pathogen Methicillin-Resistant Staphylococcus aureus (MRSA. Methods: A marine bacterium was isolated from mangrove sediment from the Red Sea coast of Jeddah, Kingdom of Saudi Arabia, and identified based on its morphological, biochemical, and molecular characteristics. The bacteriocin production using this isolate was carried out in brain heart infusion broth (BHIB medium. The Anti-bacterial activity of bacteriocin was evaluated against selected ESBL strains and MRSA by the well agar method. The effects of incubation time, pH, and temperature on the Anti-bacterial activity were studied. Results: The bacteriocin Bac-SM01 produced by B. subtilis SM01 demonstrated broad-spectrum Anti-bacterial activity against both Gram-negative and -positive bacteria. The present study is the first report that the bacteriocin Bac-SM01 inhibits the growth of ESBL producing Gram-negative strains A. baumannii, P. aeruginosa, and E. coli, and a Gram-positive MRSA strain. The optimum incubation time, pH, and temperature for the Anti-bacterial activity of Bac-SM01 was 24 h, 7, and 37°C respectively. Conclusion: The overall investigation can conclude that the bacteriocin Bac-SM01 from the marine isolate Bacillus subtilis SM01 could be used as an alternative Anti-bacterial agent in pharmaceutical products.

  12. [Antimicrobial Activity of Substances Produced by Trichoderma citrinoviride Strain VKPM F-1228: Optimization of Cultivation and Assessment of Spectrum of Individual Peptaibols].

    Science.gov (United States)

    Sadykova, V S; Kurakov, A V; Korshun, V A; Rogozhin, E A; Gromovykh, T I; Kuvarina, A E; Baranova, A A

    2015-01-01

    The Trichoderma citrinoviride VKPM F-1228 strain produces a complex of peptide-based antibiotics with antibacterial and antimycotic action. Synthesis of peptaibols is closely related to the conidiogenesis in the culture. The optimal procedure of the strain cultivation for production of peptaibols is stationary growing for 14 days at a temperature of 28 degrees C and pH 7.5 followed by formation of a dense mycelium film on the modified Saburo medium containing 30 gr/l of glucose and 12.5 gr/l of peptone. Eight individual peptaibols were extracted. The spectrum of their activity was estimated with the use of opportunistic bacteria and micromycetes as well as pathogenic clinical aspergilli. Compounds 9, 13, 14, 15 and 16 were shown active against opportunistic fungi and bacteria including methicillin resistant S. aureus, whereas compounds 9, 13 and 14 in addition showed antimycotic activity against clinical aspergilli.

  13. Determination of antimicrobial resistance pattern and Extended-Spectrum Beta Lactamases producing Pseudomonas aeruginosa strains isolated from clinical specimens of Hajar and Kashani Hospitals,Shahrekord 1387

    Directory of Open Access Journals (Sweden)

    Mana Shojapour

    2011-09-01

    Full Text Available Background: Pseudomonas aeruginosa is one of the leading causes of hospital infections in patients hospitalized for a 10 day period or over. It is also considered to be the most important cause of the burn wound infection. Approximately 75% of deaths in burned patients are due to wound infection and the subsequent septicemia. Clinical use of antibiotics has increasingly led to the global distribution of P. aeruginosa isolates with multi-drug resistance. The study was launched to determine the antimicrobial susceptibility pattern and the presence of the extended-spectrum-beta lactamase (ESBL in P.aeruginosa strains isolated from clinical specimens. Methods: Totally, 175 P. aeruginosa strains were isolated from clinical samples and identified by standard methods. The pattern of antimicrobial resistance was then performed on the isolates using Disk Agar Diffusion (DAD according to CLSI Guideline. Primary screening test for ESBL producing strains was performed by ceftazidim antibiotic disk using disk diffusion method. Combined disk method was used to confirm ESBL producing bacteria. Results: The rate of antimicrobial resistance of P.aeruginosa isolates were 64% to ticarcillin, 52.2% to cefepime, 68.6% to ticarcillin/clavolanic acid, 68.6% to ceftazidime, 67.4% to amikacin, 68.6% to gentamicin, 48% to imipenem, 77.7% to ciprofloxacin and 5.1% to polymixcine B. In the primary screening test, 120 isolates of P.aeruginosa strains were resistant to ceftazidime. In the combined disk method, 66 isolates (55% were positive for ESBLs. Conclusion: Polymixcine B was found to be the most effective antimicrobial agent in this study. Bacteria carrying ESBL genes may increase mortality and morbidity. Thus, their accurate diagnosis is of extreme importance to prevent from the treatment failure resulted from improper antibiotic administration.

  14. [Isolation of an excellent bio-flocculant-producing strain and its application in the treatment of cold-rolling waste oily water].

    Science.gov (United States)

    Lei, Guo-Yuan; Ding, Cui-Ping; Yang, Jia-Xuan

    2011-09-01

    An excellent strain (designated as T-3) which produces bio-flocculants was isolated from soil samples, and identified as Klebsiella sp. species based on the analysis of morphology, physiology and biochemistry and 16S rDNA sequences measurement. The effects of culture conditions such as pH values, temperature, carbon sources and nitrogen sources on bio-flocculants production by T-3 strain were studied. The experiment results show that T-3 strain has better adaptability to carbon sources and nitrogen sources, and higher capacity of bio-flocculants was obtained when the initial pH value of culture and temperature were 9 and 25 degrees C respectively. Based on the colorimetric reactions of proteins and polysaccharide substance, ultraviolet scanning analysis and Fourier Transform Infrared Spectroscopy analysis, it is found that the bio-flocculants produced by T-3 strain contains -OH and -COO(-) groups and belongs to anionic type flocculant. Moreover, the main component is polysaccharides. The treatment of oily cold-rolling wastewater by the bio-flocculant was investigated and the better result was obtained. When the dosages of CaCl2, bio-flocculants and poly aluminium chloride were 4 g x L(-1), 10% (volume fraction) and 1 g x L(-1) respectively, and the pH value was 7.0, the oil concentration, COD and turbidity were decreased to 10 mg x L(-1), 218.4 mg x L(-1) and 1.36 from 4 819 mg x L(-1), 28 456.8 mg x L(-1) and 3 950 with the removal efficiencies of 99.79%, 92.32% and 99.97% respectively. The interaction between flocculant and oily droplets is achieved by the interaction of Van der Waals force, hydrogen bond and the bridged coordination of Ca2+, in which the bridged coordination of Ca2+ is the dominant.

  15. Microbial diversity of mangrove sediment in Shenzhen Bay and gene cloning, characterization of an isolated phytase-producing strain of SPC09 B. cereus.

    Science.gov (United States)

    Zhang, Shengpeng; Liao, Shao-An; Yu, Xiaoyuan; Lu, Hongwu; Xian, Jian-An; Guo, Hui; Wang, Anli; Xie, Jian

    2015-06-01

    Phytases hydrolyze phytate to release inorganic phosphate, which decreases the requirement for phosphorus in fertilizers for crops and thus reduces environmental pollutants. This study analyzed microbial communities in rhizosphere sediment, collected in September 2012 from Shenzhen Bay, Guangdong, China, using high-throughput pyrosequencing; the results showed that the dominant taxonomic phyla were Chloroflexi, Firmicutes, and Proteobacteria, and the proportion of the beneficial bacteria, Bacillus, was 4.95 %. Twenty-nine culturable, phytase-producing bacteria were isolated, their phosphorus solubilization capacity was analyzed, and they were taxonomically characterized. Their phylogenetic placement was determined using 16S ribosomal RNA (rRNA) gene sequence analysis. The result shows that most of the isolates are members of the order Bacillales, although seven strains of Enterobacteriales, two strains of Pseudomonadales, and one strain of Oceanospirillales were also identified. The phytase gene was cloned from SPC09, Bacillus cereus, which showed the highest phosphorus solubilizing ability among the isolated strains. The gene encoded a primary translation product of 335 amino acids. A construct including the 1005-nt ORF fragment, Bc-phy, was transformed into Escherichia coli. The recombinant phytase was produced and purified, which revealed the temperature optima at 60 °C and pH optima at 6.5. The assessment by quantitative PCR (qPCR) showed an abundance of bacteria containing the Bc-phy gene; the level was generally higher in the mangrove forest than in the tidal flats and in surface soil compared to bottom soil, and the highest value was obtained in June. Herein, we report on the cloning, characterization, and activity of a novel phytase isolated from a mangrove system.

  16. Draft genome sequences of two protease-producing strains of Arsukibacterium, isolated from two cold and alkaline environments

    DEFF Research Database (Denmark)

    Lylloff, Jeanette Eva; Hansen, Lea Benedicte Skov; Jepsen, Morten

    2015-01-01

    Arsukibacterium ikkense GCM72(T) and a close relative, Arsukibacterium sp. MJ3, were isolated from two cold and alkaline environments as producers of extracellular proteolytic enzymes active at high pH and low temperature. This report describes the two draft genome sequences, which may serve...

  17. Genome sequence of the thermophilic strain Bacillus coagulans XZL4, an efficient pentose-utilizing producer of chemicals.

    Science.gov (United States)

    Su, Fei; Xu, Ke; Zhao, Bo; Tai, Cui; Tao, Fei; Tang, Hongzhi; Xu, Ping

    2011-11-01

    Bacillus coagulans XZL4 is an efficient pentose-utilizing producer of important platform compounds, such as l-lactic acid, 2,3-butanediol, and acetoin. Here we present a 2.8-Mb assembly of its genome. Simple and efficient carbohydrate metabolism systems, especially the transketolase/transaldolase pathway, make it possible to convert pentose sugars to products at high levels.

  18. A new regulatory mechanism controlling carotenogenesis in the fungus Mucor circinelloides as a target to generate β-carotene over-producing strains by genetic engineering.

    Science.gov (United States)

    Zhang, Yingtong; Navarro, Eusebio; Cánovas-Márquez, José T; Almagro, Lorena; Chen, Haiqin; Chen, Yong Q; Zhang, Hao; Torres-Martínez, Santiago; Chen, Wei; Garre, Victoriano

    2016-06-07

    Carotenoids are natural pigments with antioxidant properties that have important functions in human physiology and must be supplied through the diet. They also have important industrial applications as food colourants, animal feed additives and nutraceuticals. Some of them, such as β-carotene, are produced on an industrial scale with the use of microorganisms, including fungi. The mucoral Blakeslea trispora is used by the industry to produce β-carotene, although optimisation of production by molecular genetic engineering is unfeasible. However, the phylogenetically closely related Mucor circinelloides, which is also able to accumulate β-carotene, possesses a vast collection of genetic tools with which to manipulate its genome. This work combines classical forward and modern reverse genetic techniques to deepen the regulation of carotenoid synthesis and generate candidate strains for biotechnological production of β-carotene. Mutagenesis followed by screening for mutants with altered colour in the dark and/or in light led to the isolation of 26 mutants that, together with eight previously isolated mutants, have been analysed in this work. Although most of the mutants harboured mutations in known structural and regulatory carotenogenic genes, eight of them lacked mutations in those genes. Whole-genome sequencing of six of these strains revealed the presence of many mutations throughout their genomes, which makes identification of the mutation that produced the phenotype difficult. However, deletion of the crgA gene, a well-known repressor of carotenoid biosynthesis in M. circinelloides, in two mutants (MU206 and MU218) with high levels of β-carotene resulted in a further increase in β-carotene content to differing extents with respect to the crgA single-null strain; in particular, one strain derived from MU218 was able to accumulate up to 4 mg/g of β-carotene. The additive effect of crgA deletion and the mutations present in MU218 suggests the existence of a

  19. Exopolysaccharide-producing Bifidobacterium animalis subsp. lactis strains and their polymers elicit different responses on immune cells from blood and gut associated lymphoid tissue.

    Science.gov (United States)

    Hidalgo-Cantabrana, Claudio; Nikolic, Milica; López, Patricia; Suárez, Ana; Miljkovic, Marija; Kojic, Milan; Margolles, Abelardo; Golic, Natasa; Ruas-Madiedo, Patricia

    2014-04-01

    The effect of exopolysaccharide (EPS) producing bifidobacteria, and the EPS derived thereof, on the modulation of immune response was evaluated. Cells isolated from gut associated lymphoid tissue (GALT) and from peripheral blood mononuclear cells (PBMC) of naïve rats were used. The proliferation and cytokine production of these immune cells in the presence of the three isogenic Bifidobacterium animalis subsp. lactis strains (A1, A1dOx and A1dOxR), as well as their purified polymers, were in vitro analysed. The cytokine pattern produced by immune cells isolated from GALT showed that most levels remained stable in the presence of the three strains or their corresponding polymers. However, in PBMC the UV-inactivated bacteria induced higher levels of the ratios IFNγ/IL-17, TNFα/IL-10 and TNFα/TGFβ, and no variation in the ratio IFNγ/IL-4. Thus, B. animalis subsp. lactis strains were able to activate blood monocytes as well as T lymphocytes towards a mild inflammatory Th1 response. Furthermore, only the EPS-A1dOxR was able to stimulate a response in a similar way than its EPS-producing bacterium. Our work supports the notion that some bifidobacterial EPS could play a role in mediating the dialog of these microorganisms with the immune system. In addition, this study emphasizes the effect that the origin of the immune cells has in results obtained; this could explain the great amount of contradiction found in literature about the immunomodulation capability of EPS from probiotic bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Identification, genetic diversity and cereulide producing ability of Bacillus cereus group strains isolated from Beninese traditional fermented food condiments

    DEFF Research Database (Denmark)

    Thorsen, Line; Azokpota, Paulin; Hansen, Bjarne Munk

    2010-01-01

    Bacillus cereus sensu lato is often detected in spontaneously fermented African foods but is rarely identified to species level. Only some of the B. cereus group species are reported to be pathogenic to humans and identification to species level is necessary to estimate the safety of these products...... (cluster 1). Highly similar PM13 profiles were obtained for seven of the isolates, one from afitin, one from iru and five from sonru (cluster 2). Four of the isolates, one from afitin and three from sonru, did not form any particular cluster. The PM13 profiles of cluster 2 isolates were identical to those...... which are specific to emetic toxin producers. Cereulide production of these isolates was confirmed by liquid chromatography mass spectrometry/mass spectrometry. This is the first report on cereulide producing B. cereus in African fermented foods. Occurrence of the opportunistic human pathogen B. cereus...

  1. The Draft Genome Sequence of Clostridium sp. Strain NJ4, a Bacterium Capable of Producing Butanol from Inulin Through Consolidated Bioprocessing.

    Science.gov (United States)

    Jiang, Yujia; Lu, Jiasheng; Chen, Tianpeng; Yan, Wei; Dong, Weiliang; Zhou, Jie; Zhang, Wenming; Ma, Jiangfeng; Jiang, Min; Xin, Fengxue

    2018-05-23

    A novel butanogenic Clostridium sp. NJ4 was successfully isolated and characterized, which could directly produce relatively high titer of butanol from inulin through consolidated bioprocessing (CBP). The assembled draft genome of strain NJ4 is 4.09 Mp, containing 3891 encoded protein sequences with G+C content of 30.73%. Among these annotated genes, a levanase, a hypothetical inulinase, and two bifunctional alcohol/aldehyde dehydrogenases (AdhE) were found to play key roles in the achievement of ABE production from inulin through CBP.

  2. Purification and characterization of two new cell-bound bioactive compounds produced by wild Lactococcus lactis strain.

    Science.gov (United States)

    Saraiva, Margarete Alice Fontes; Brede, Dag Anders; Nes, Ingolf Figved; Baracat-Pereira, Maria Cristina; de Queiroz, Marisa Vieira; de Moraes, Célia Alencar

    2017-07-03

    Novel compounds and innovative methods are required considering that antibiotic resistance has reached a crisis point. In the study, two cell-bound antimicrobial compounds produced by Lactococcus lactis ID1.5 were isolated and partially characterized. Following purification by cationic exchange and a solid-phase C18 column, antimicrobial activity was recovered after three runs of RPC using 60% (v/v) and 100% (v/v) of 2-propanol for elution, suggesting that more than one antimicrobial compound were produced by L. lactis ID1.5, which were in this study called compounds AI and AII. The mass spectrum of AI and AII showed major intensity ions at m/z 1070.05 and 955.9 Da, respectively. The compound AI showed a spectrum of antimicrobial activity mainly against L. lactis species, while the organisms most sensitive to compound AII were Bacillus subtilis, Listeria innocua, Streptococcus pneumoniae and Pseudomonas aeruginosa. The antimicrobial activity of both compounds was suppressed by treatment with Tween 80. Nevertheless, both compounds showed high stability to heat and proteases treatments. The isolated compounds, AI and AII, showed distinct properties from other antimicrobial substances already reported as produced by L. lactis, and have a significant inhibitory effect against two clinically important respiratory pathogens. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Genomic analysis of the aconidial and high-performance protein producer, industrially relevant Aspergillus niger SH2 strain.

    Science.gov (United States)

    Yin, Chao; Wang, Bin; He, Pan; Lin, Ying; Pan, Li

    2014-05-15

    Aspergillus niger is usually regarded as a beneficial species widely used in biotechnological industry. Obtaining the genome sequence of the widely used aconidial A. niger SH2 strain is of great importance to understand its unusual production capability. In this study we assembled a high-quality genome sequence of A. niger SH2 with approximately 11,517 ORFs. Relatively high proportion of genes enriched for protein expression related FunCat items verify its efficient capacity in protein production. Furthermore, genome-wide comparative analysis between A. niger SH2 and CBS513.88 reveals insights into unique properties of A. niger SH2. A. niger SH2 lacks the gene related with the initiation of asexual sporulation (PrpA), leading to its distinct aconidial phenotype. Frame shift mutations and non-synonymous SNPs in genes of cell wall integrity signaling, β-1,3-glucan synthesis and chitin synthesis influence its cell wall development which is important for its hyphal fragmentation during industrial high-efficiency protein production. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. [EFFICIENCY OF INTRODUCING CAROTENE PRODUCING STRAINS BACILLUS SP. 1.1 AND B. AMYLOLIQUEFACIENS UCM B-5113 INTO THE CHIKENS DIET].

    Science.gov (United States)

    Nechypurenko, O O; Kharhota M A; Avdeeva, L V

    2015-01-01

    It was shown the efficiency of carotene producing strains Bacillus sp. 1.1 and B. amyloliquefaciens UCM B-5113 in the diet of chickens. Also it was detected the lowering of the quantitative content of bacterial genera Enterococcus, Staphylococcus, family Enterobacteriaceae in the gut after eating by chickens cross "H&N Brown Nick" fodder with strains Bacillus sp. 1.1 and B. amyloliquefaciens UCM B-5113 alone and in composition in quantities 1 x 10(10) CFU per 1 g of feed. On the 18th day after introduction of cultures Bacillus sp. 1.1, B. amyloliquefaciens UCM B-5113 and their composition in the diet of poultry we revealed the increasing of body weight by 21.6, 7.6 and 22.0%, respectively, comparesing to controls. Also due to Bacillus sp. 1.1 it was detected the restore of intestinal villous structures, tissues of spleen, liver and heart. We found the additive effect of the composition of the investigated strains of bacteria genus Bacillus to the chickens.

  5. Surveillance of Virulence Markers and Antibiotic Resistance of Shiga toxin Producing E.coli O157:H7 Strains from Meats Purchase in Shiraz

    Directory of Open Access Journals (Sweden)

    Mohammad Kargar

    2011-09-01

    Full Text Available Background: Shiga toxin Producing Escherichia coli O157:H7 is a common pathogen in cattle, which occasional causes some human disease. This bacterium can potentially contaminate meat and clinical cases of E.coli O157:H7 infections are often associated with consumption of undercooked ground beef. Methods: In this cross-sectional study 122 samples of ground meat were collected and after enrichment in specific culture media and evaluation sorbitol fermentation and their β-glucoronidase activity, the isolation of E.coli O157:H7 strains have been confirmed with specific antisera. Then virulence genes verotoxin, intimin and hemolysin with multiplex PCR and antibiotic resistance strains with disk diffusion method have been tested. Results: Out of specimens that have been supplied, 119 sorbitol negative colonies isolated which 3 strains O157:H7 (2.45% with specific antisera confirmed. Out of considered virulence genes, in two cases of these samples (1.64% the stx1 and eaeA genes were seen and also 2 isolated bacteria had resistance to erythromycin, tetracycline, ampicillin, penicillin, clindamicin, cefixime, novobiocin, and gentamicin antibiotics. Conclusion: As this organism lives in intestines of healthy cattle, preventive measures on cattle farms and during meat processing are necessary.

  6. Diversity and dynamic of lactic acid bacteria strains during aging of a long ripened hard cheese produced from raw milk and undefined natural starter.

    Science.gov (United States)

    Pogačić, Tomislav; Mancini, Andrea; Santarelli, Marcela; Bottari, Benedetta; Lazzi, Camilla; Neviani, Erasmo; Gatti, Monica

    2013-12-01

    The aim of this study was to explore diversity and dynamic of indigenous LAB strains associated with a long ripened hard cheese produced from raw milk and undefined natural starter such as PDO Grana Padano cheese. Samples of milk, curd, natural whey culture and cheeses (2nd, 6th, 9th and 13th months of ripening) were collected from 6 cheese factories in northern Italy. DNA was extracted from each sample and from 194 LAB isolates. tRNA(Ala)-23S rDNA-RFLP was applied to identify isolates. Strain diversity was assessed by (GTG)5 rep-PCR and RAPD(P1)-PCR. Finally, culture-independent LH-PCR (V1-V2 16S-rDNA), was considered to explore structure and dynamic of the microbiota. Grana Padano LAB were represented mainly by Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus and Pediococcus acidilactici, while the structure and dynamic of microbiota at different localities was specific. The strength of this work is to have focused the study on isolates coming from more than one cheese factories rather than a high number of isolates from one unique production. We provided a valuable insight into inter and intraspecies diversity of typical LAB strains during ripening of traditional PDO Grana Padano, contributing to the understanding of specific microbial ecosystem of this cheese. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Screening and characterization of bacteriocins produced by some Strains of Lactobacillus spp isolated from Iranian Dairy products

    Directory of Open Access Journals (Sweden)

    S Mirdamadi

    2011-11-01

    Full Text Available In this study, the inhibitory effects of bacteriocins of lactobacilli which were isolated from Iranian traditional dairy products was determined against known gram positive, gram negative and yeast by well diffusion technique. Among 8 isolates with higher capability of bacteriocin production, 2 isolates were selected for further investigations. The bacteriocins were purified by iso-propanol and ammonium sulfate precipitation following by dialysis and chromatography technique. The molecular weight of bacteriocins was determined as 45 to 66/2 KDa. by SDS-page electrophoresis. According to the results, the produced bacteriocins had more inhibition effect on Micrococcus luteus PTCC1169, Staphylococcus epidermidis PTCC1435 as well as Bacillus cereus PTCC1247 and with lesser degree of extent on Listeria monocytogenes PTCC 1301. Results also revealed that, Micrococcus luteus  was the most sensitive bacterium among indicator bacteria, while Candid albicans PTCC 5027 identified as the most resistance organism. This research showed that, bacteriocins produced by lactobacilli isolated from traditional dairy products have high potency to be used against microbial pathogens and could be applied as bio-preservative in food products.

  8. Detection and Characterization of Shiga Toxin Producing Escherichia coli, Salmonella spp., and Yersinia Strains from Human, Animal, and Food Samples in San Luis, Argentina

    Science.gov (United States)

    Favier, Gabriela Isabel; Lucero Estrada, Cecilia; Cortiñas, Teresa Inés; Escudero, María Esther

    2014-01-01

    Shiga toxin producing Escherichia coli (STEC), Salmonella spp., and Yersinia species was investigated in humans, animals, and foods in San Luis, Argentina. A total of 453 samples were analyzed by culture and PCR. The antimicrobial susceptibility of all the strains was studied, the genomic relationships among isolates of the same species were determined by PFGE, and the potencial virulence of Y. enterocolitica strains was analyzed. Yersinia species showed higher prevalence (9/453, 2.0%, 95% CI, 0.7–3.3%) than STEC (4/453, 0.9%, 95% CI, 0–1.8%) and Salmonella spp. (3/453, 0.7%, 95% CI, 0–1.5%). Y. enterocolitica and Y. intermedia were isolated from chicken carcasses (6/80, 7.5%, 95% CI, 1.5–13.5%) and porcine skin and bones (3/10, 30%, 95% CI, 0–65%). One STEC strain was recovered from human feces (1/70, 1.4%, 95% CI, 0–4.2%) and STEC stx1/stx2 genes were detected in bovine stools (3/129, 2.3%, 95% CI, 0–5.0%). S. Typhimurium was isolated from human feces (1/70, 1.4%, 95% CI, 0–4.2%) while one S. Newport and two S. Gaminara strains were recovered from one wild boar (1/3, 33%, 95% CI, 0–99%). The knowledge of prevalence and characteristics of these enteropathogens in our region would allow public health services to take adequate preventive measures. PMID:25177351

  9. Comparative evaluation of extracellular β-D-fructofuranosidase in submerged and solid-state fermentation produced by newly identified Bacillus subtilis strain.

    Science.gov (United States)

    Lincoln, Lynette; More, Sunil S

    2018-04-17

    To screen and identify a potential extracellular β-D-fructofuranosidase or invertase producing bacterium from soil, and comparatively evaluate the enzyme biosynthesis under submerged and solid-state fermentation. Extracellular invertase producing bacteria were screened from soil. Identification of the potent bacterium was performed based on microscopic examinations and 16S rDNA molecular sequencing. Bacillus subtilis LYN12 invertase secretion was surplus with wheat bran humidified with molasses medium (70%), with elevated activity at 48 h and 37 °C under solid-state fermentation, whereas under submerged conditions increased activity was observed at 24 h and 45 °C in the molasses medium. The study revealed a simple fermentative medium for elevated production of extracellular invertase from a fast growing Bacillus strain. Bacterial invertases are scarce and limited reports are available. By far, this is the first report on the comparative analysis of optimization of extracellular invertase synthesis from Bacillus subtilis strain by submerged and solid-state fermentation. The use of agricultural residues increased yields resulting in development of a cost-effective and stable approach. Bacillus subtilis LYN12 invertase possesses excellent fermenting capability to utilize agro-industrial residues under submerged and solid-state conditions. This could be a beneficial candidate in food and beverage processing industries. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. A novel cholesterol-producing Pichia pastoris strain is an ideal host for functional expression of human Na,K-ATPase α3β1 isoform.

    Science.gov (United States)

    Hirz, Melanie; Richter, Gerald; Leitner, Erich; Wriessnegger, Tamara; Pichler, Harald

    2013-11-01

    The heterologous expression of mammalian membrane proteins in lower eukaryotes is often hampered by aberrant protein localization, structure, and function, leading to enhanced degradation and, thus, low expression levels. Substantial quantities of functional membrane proteins are necessary to elucidate their structure-function relationships. Na,K-ATPases are integral, human membrane proteins that specifically interact with cholesterol and phospholipids, ensuring protein stability and enhancing ion transport activity. In this study, we present a Pichia pastoris strain which was engineered in its sterol pathway towards the synthesis of cholesterol instead of ergosterol to foster the functional expression of human membrane proteins. Western blot analyses revealed that cholesterol-producing yeast formed enhanced and stable levels of human Na,K-ATPase α3β1 isoform. ATPase activity assays suggested that this Na,K-ATPase isoform was functionally expressed in the plasma membrane. Moreover, [(3)H]-ouabain cell surface-binding studies underscored that the Na,K-ATPase was present in high numbers at the cell surface, surpassing reported expression strains severalfold. This provides evidence that the humanized sterol composition positively influenced Na,K-ATPase α3β1 stability, activity, and localization to the yeast plasma membrane. Prospectively, cholesterol-producing yeast will have high potential for functional expression of many mammalian membrane proteins.

  11. Intracellular synthesis of glutamic acid in Bacillus methylotrophicus SK19.001, a glutamate-independent poly(γ-glutamic acid)-producing strain.

    Science.gov (United States)

    Peng, Yingyun; Zhang, Tao; Mu, Wanmeng; Miao, Ming; Jiang, Bo

    2016-01-15

    Bacillus methylotrophicus SK19.001 is a glutamate-independent strain that produces poly(γ-glutamic acid) (γ-PGA), a polymer of D- and L-glutamic acids that possesses applications in food, the environment, agriculture, etc. This study was undertaken to explore the synthetic pathway of intracellular L- and D-glutamic acid in SK19.001 by investigating the effects of tricarboxylic acid cycle intermediates and different amino acids as metabolic precursors on the production of γ-PGA and analyzing the activities of the enzymes involved in the synthesis of L- and D-glutamate. Tricarboxylic acid cycle intermediates and amino acids could participate in the synthesis of γ-PGA via independent pathways in SK19.001. L-Aspartate aminotransferase, L-glutaminase and L-glutamate synthase were the enzymatic sources of L-glutamate. Glutamate racemase was responsible for the formation of D-glutamate for the synthesis of γ-PGA, and the synthetase had stereoselectivity for glutamate substrate. The enzymatic sources of L-glutamate were investigated for the first time in the glutamate-independent γ-PGA-producing strain, and multiple enzymatic sources of L-glutamate were verified in SK19.001, which will benefit efforts to improve production of γ-PGA with metabolic engineering strategies. © 2015 Society of Chemical Industry.

  12. Foliar Application of Extract from an Azalomycin-Producing Streptomyces malaysiensis Strain MJM1968 Suppresses Yam Anthracnose Caused by Colletotrichum gloeosporioides.

    Science.gov (United States)

    Arunachalam Palaniyandi, Sasikumar; Yang, Seung Hwan; Suh, Joo-Woh

    2016-06-28

    Yam anthracnose caused by Colletotrichum gloeosporioides (C.g) is the most devastating disease of yam (Dioscorea sp.). In the present study, we evaluated the culture filtrate extract (CFE) of azalomycin-producing Streptomyces malaysiensis strain MJM1968 for the control of yam anthracnose. MJM1968 showed strong antagonistic activity against C.g in vitro. Furthermore, the MJM1968 CFE was tested for inhibition of spore germination in C.g, where it completely inhibited spore germination at a concentration of 50 μg/ml. To assess the in planta efficacy of the CFE and spores of MJM1968 against C.g, a detached leaf bioassay was conducted, which showed both the treatments suppressed anthracnose development on detached yam leaves. Furthermore, a greenhouse study was conducted to evaluate the CFE from MJM1968 as a fungicide for the control of yam anthracnose. The CFE non-treated plants showed a disease severity of >92% after 90 days of artificial inoculation with C.g, whereas the disease severity of CFE-treated and benomyl-treated yam plants was reduced to 26% and 15%, respectively, after 90 days. Analysis of the yam tubers from the CFE-treated and non-treated groups showed that tubers from the CFE-treated plants were larger than that of non-treated plants, which produced abnormal smaller tubers typical of anthracnose. This study demonstrated the utility of the CFE from S. malaysiensis strain MJM1968 as a biofungicide for the control of yam anthracnose.

  13. In silico Prediction, in vitro Antibacterial Spectrum, and Physicochemical Properties of a Putative Bacteriocin Produced by Lactobacillus rhamnosus Strain L156.4

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    Letícia de C. Oliveira

    2017-05-01

    Full Text Available A bacteriocinogenic Lactobacillus rhamnosus L156.4 strain isolated from the feces of NIH mice was identified by 16S rRNA gene sequencing and MALDI-TOF mass spectrometry. The entire genome was sequenced using Illumina, annotated in the PGAAP, and RAST servers, and deposited. Conserved genes associated with bacteriocin synthesis were predicted using BAGEL3, leading to the identification of an open reading frame (ORF that shows homology with the L. rhamnosus GG (ATCC 53103 prebacteriocin gene. The encoded protein contains a conserved protein motif associated a structural gene of the Enterocin A superfamily. We found ORFs related to the prebacteriocin, immunity protein, ABC transporter proteins, and regulatory genes with 100% identity to those of L. rhamnosus HN001. In this study, we provide evidence of a putative bacteriocin produced by L. rhamnosus L156.4 that was further confirmed by in vitro assays. The antibacterial activity of the substances produced by this strain was evaluated using the deferred agar-spot and spot-on-the lawn assays, and a wide antimicrobial activity spectrum against human and foodborne pathogens was observed. The physicochemical characterization of the putative bacteriocin indicated that it was sensitive to proteolytic enzymes, heat stable and maintained its antibacterial activity in a pH ranging from 3 to 9. The activity against Lactobacillus fermentum, which was used as an indicator strain, was detected during bacterial logarithmic growth phase, and a positive correlation was confirmed between bacterial growth and production of the putative bacteriocin. After a partial purification from cell-free supernatant by salt precipitation, the putative bacteriocin migrated as a diffuse band of approximately 1.0–3.0 kDa by SDS-PAGE. Additional studies are being conducted to explore its use in the food industry for controlling bacterial growth and for probiotic applications.

  14. Purification and characterization of enterocin 62-6, a two-peptide bacteriocin produced by a vaginal strain of Enterococcus faecium: Potential significance in bacterial vaginosis

    Science.gov (United States)

    Dezwaan, Diane C.; Mequio, Michael J.; Littell, Julia S.; Allen, Jonathan P.; Rossbach, Silvia; Pybus, Vivien

    2009-01-01

    A bacteriocin produced by a vaginal isolate of Enterococcus faecium strain 62-6, designated enterocin 62-6, was characterized following purification and DNA sequence analysis and compared to previously described bacteriocins. Enterocin 62-6 was isolated from brain heart infusion (BHI) culture supernatants using ammonium sulfate precipitation followed by elution from a Sepharose cation exchange column using a continuous salt gradient (0.1–0.7 M NaCl). SDS-PAGE of an active column fraction resulted in an electrophoretically pure protein, which corresponded to the growth inhibition of the sensitive Lactobacillus indicator strain in the gel overlay assay. Purified enterocin 62-6 was shown to be heat- and pH-stable, and sensitive to the proteolytic enzymes α-chymotrypsin and pepsin. Results from mass spectrometry suggested that it comprised two peptides of 5206 and 5219±1 Da, which was confirmed by DNA sequence analysis. The characteristics of enterocin 62-6 as a small, heat- and pH-stable, cationic, hydrophobic, two-peptide, plasmid-borne bacteriocin, with an inhibitory spectrum against a broad range of Gram-positive but not Gram-negative bacteria, were consistent with its classification as a class IIc bacteriocin. Furthermore, its wide spectrum of growth inhibitory activity against Gram-positive bacteria of vaginal origin including lactobacilli, and stability under the acidic conditions of the vagina, are consistent with our hypothesis that it could have potential significance in disrupting the ecology of the vaginal tract and pave the way for the establishment of the abnormal microbiota associated with the vaginal syndrome bacterial vaginosis. This is the first class IIc bacteriocin produced by a strain of E. faecium of vaginal origin to be characterized. PMID:19578555

  15. In silico Prediction, in vitro Antibacterial Spectrum, and Physicochemical Properties of a Putative Bacteriocin Produced by Lactobacillus rhamnosus Strain L156.4

    Science.gov (United States)

    Oliveira, Letícia de C.; Silveira, Aline M. M.; Monteiro, Andréa de S.; dos Santos, Vera L.; Nicoli, Jacques R.; Azevedo, Vasco A. de C.; Soares, Siomar de C.; Dias-Souza, Marcus V.; Nardi, Regina M. D.

    2017-01-01

    A bacteriocinogenic Lactobacillus rhamnosus L156.4 strain isolated from the feces of NIH mice was identified by 16S rRNA gene sequencing and MALDI-TOF mass spectrometry. The entire genome was sequenced using Illumina, annotated in the PGAAP, and RAST servers, and deposited. Conserved genes associated with bacteriocin synthesis were predicted using BAGEL3, leading to the identification of an open reading frame (ORF) that shows homology with the L. rhamnosus GG (ATCC 53103) prebacteriocin gene. The encoded protein contains a conserved protein motif associated a structural gene of the Enterocin A superfamily. We found ORFs related to the prebacteriocin, immunity protein, ABC transporter proteins, and regulatory genes with 100% identity to those of L. rhamnosus HN001. In this study, we provide evidence of a putative bacteriocin produced by L. rhamnosus L156.4 that was further confirmed by in vitro assays. The antibacterial activity of the substances produced by this strain was evaluated using the deferred agar-spot and spot-on-the lawn assays, and a wide antimicrobial activity spectrum against human and foodborne pathogens was observed. The physicochemical characterization of the putative bacteriocin indicated that it was sensitive to proteolytic enzymes, heat stable and maintained its antibacterial activity in a pH ranging from 3 to 9. The activity against Lactobacillus fermentum, which was used as an indicator strain, was detected during bacterial logarithmic growth phase, and a positive correlation was confirmed between bacterial growth and production of the putative bacteriocin. After a partial purification from cell-free supernatant by salt precipitation, the putative bacteriocin migrated as a diffuse band of approximately 1.0–3.0 kDa by SDS-PAGE. Additional studies are being conducted to explore its use in the food industry for controlling bacterial growth and for probiotic applications. PMID:28579977

  16. Enterocin HZ produced by a wild Enterococcus faecium strain isolated from a traditional, starter-free pickled cheese.

    Science.gov (United States)

    Yildirim, Zeliha; Bilgin, Harun; Isleroglu, Hilal; Tokatli, Kader; Sahingil, Didem; Yildirim, Metin

    2014-05-01

    Bacteriogenic Enterococcus faecium HZ was identified by using biochemical (Strep-API 20, API-50 CHL, fatty acid profile) and 16S rRNA analysis (99·99 %). Ent. faecium HZ was sensitive to clinically important antibiotics such as vancomycin, and did not have gelatinase and haemolysis activities. Enterocin HZ, a bacteriocin from Ent. faecium HZ, was sensitive to papain and tyripsin, but resistant to pepsin, lipase, catalase, α-amylase, organic solvents, detergents, ß-mercaptoethanol, and heat treatment (90 °C/30 min). It was biologically active at pH 2·0-9·0 and synthesised at the highest level in MRS or M17 broth at 32 or 37 °C with an inoculum amount of 0·1-0·5 % and an initial pH of 6·0-7·0. Enterocin HZ production reached maximum level at middle and late logarithmic phase and its molecular weight was ∼4·5 kDa. It was active against some Gram-positive foodborne bacteria. Ent. faecium HZ or its bacteriocin enterocin HZ is a good candidate to be studied as a food biopreservative since enterocin HZ showed strong bactericidal activity against Listeria monocytogenes in UHT milk and also Ent. faecium HZ grew very well in milk and produced enterocin HZ at maximum level.

  17. Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from 'Marcha'.

    Science.gov (United States)

    Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

    2014-01-01

    In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.

  18. Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from ‘Marcha’

    Science.gov (United States)

    Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

    2014-01-01

    In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative. PMID:25477937

  19. Purification and characterization of an L-arabinose isomerase from an isolated strain of Geobacillus thermodenitrificans producing D-tagatose.

    Science.gov (United States)

    Kim, Hye-Jung; Oh, Deok-Kun

    2005-11-04

    The araA gene, encoding l-arabinose isomerase (AI), from the thermophilic bacterium Geobacillus thermodenitrificans was cloned and expressed in Escherichia coli. Recombinant AI was isolated with a final purity of about 97% and a final specific activity of 2.10 U/mg. The molecular mass of the purified AI was estimated to be about 230 kDa to be a tetramer composed of identical subunits. The AI exhibited maximum activity at 70 degrees C and pH 8.5 in the presence of Mn2+. The enzyme was stable at temperatures below 60 degrees C and within the pH range 7.5-8.0. d-Galactose and l-arabinose as substrate were isomerized with high activities. Ribitol was the strongest competitive inhibitor of AI with a Ki of 5.5mM. The apparent Km and Vmax for L-arabinose were 142 mM and 86 U/mg, respectively, whereas those for d-galactose were 408 mM and 6.9 U/mg, respectively. The catalytic efficiency (kcat/Km) was 48 mM(-1)min(-1) for L-arabinose and 0.5mM(-1)min(-1) for D-galactose. Mn2+ was a competitive activator and increased the thermal stability of the AI. The D-tagatose yield produced by AI from d-galactose was 46% without the addition of Mn2+ and 48% with Mn2+ after 300 min at 65 degrees C.

  20. Incidence of Shiga toxin-producing Escherichia coli strains in beef, pork, chicken, deer, boar, bison, and rabbit retail meat.

    Science.gov (United States)

    Magwedere, Kudakwashe; Dang, Huu Anh; Mills, Edward W; Cutter, Catherine N; Roberts, Elisabeth L; DeBroy, Chitrita

    2013-03-01

    The objective of the current study was to determine the incidence of contamination by the top 7 Shiga toxin-producing Escherichia coli (STEC) O-groups, responsible for the majority of E. coli infections in human beings, in retail meat from different animal species. Samples from ground beef (n = 51), ground pork (n = 16), ground chicken (n = 16), and game meat (deer, wild boar, bison, and rabbit; n = 55) were collected from retail vendors for the detection of 7 STEC O-groups (O26, O45, O103, O111, O121, O145, and O157). Meat samples were tested by using a multiplex polymerase chain reaction assay targeting the wzx gene of O antigen gene clusters of the 7 STEC O-groups. The positive samples were further tested for Shiga toxin genes (stx1 and stx2). Out of a total of 83 ground beef, pork, and chicken samples, 17 (20%) carried O121, 9 (10%) carried O45, 8 (9%) carried O157, 3 (3%) carried O103, and 1 (1%) carried O145. None of the samples were positive for O26, O111, or the stx gene. All 3 white-tailed deer samples (100%) were positive for O45, O103, or both, 2 (10%) out of 20 red deer samples exhibited the presence of O103, and all 3 bison samples were contaminated with either O121, O145, or O157. One sample from ground deer, contaminated with E. coli O45, carried the stx1 gene. This preliminary investigation illustrates the importance of microbiological testing of pathogens in meat products, as well as the recognized need for increased surveillance and research on foodborne pathogens.

  1. Detection and Molecular Characterization of Escherichia coli Strains Producers of Extended-Spectrum and CMY-2 Type Beta-Lactamases, Isolated from Turtles in Mexico.

    Science.gov (United States)

    Cortés-Cortés, Gerardo; Lozano-Zarain, Patricia; Torres, Carmen; Castañeda, Miguel; Sánchez, Gabriela Moreno; Alonso, Carla A; López-Pliego, Liliana; Mayen, María G Gutiérrez; Martínez-Laguna, Ygnacio; Rocha-Gracia, Rosa Del Carmen

    2016-09-01

    Multidrug-resistant bacteria are a growing problem in different environments and hosts, but scarce information exists about their prevalence in reptiles. The aim of this study was to analyze the resistance mechanisms, molecular typing, and plasmid content of cefotaxime-resistant (CTX(R)) Escherichia coli isolates recovered from cloacal samples of 71 turtles sheltered in a herpetarium in Mexico. CTX(R)-E. coli were recovered in 11 of 71 samples (15.5%), and one isolate/sample was characterized. Extended-spectrum β-lactamase (ESBL)-producing E. coli isolates were detected in four samples (5.6%): two strains carried the blaCTX-M-2 gene (phylogroup D and ST2732) and two contained the blaCTX-M-15 gene (phylogroup B1 and lineages ST58 and ST156). The blaCMY-2 gene was detected by PCR in E. coli isolates of eight samples (9.8%) (one of them also carried blaCTX-M-2); these isolates were distributed into phylogroups A (n = 1), B1 (n = 6), and D (n = 1) and typed as ST155, ST156, ST2329, and ST2732. Plasmid-mediated quinolone resistance (PMQR) genes were detected in five isolates [aac(6')Ib-cr, qnrA, qnrB19, and oqxB]. From three to five replicon plasmids were detected among the strains, being IncFIB, IncI1, IncFrep, and IncK the most prevalent. ESBL or pAmpC genes were transferred by conjugation in four strains, and the blaCTX-M-15 and blaCMY-2 genes were localized in IncFIB or IncI1 plasmids by Southern blot hybridization assays. Class 1 and/or class 2 integrons were detected in eight strains with six different structures of gene cassette arrays. Nine pulsed-field gel electrophoresis patterns were found among the 11 studied strains. To our knowledge, this is the first detection of ESBL, CMY-2, PMQR, and mobile determinants of antimicrobial resistance in E. coli of turtle origin, highlighting the potential dissemination of multidrug-resistant bacteria from these animals to other environments and hosts, including humans.

  2. Antimicrobial susceptibility and mechanisms of fosfomycin resistance in extended-spectrum β-lactamase-producing Escherichia coli strains from urinary tract infections in Wenzhou, China.

    Science.gov (United States)

    Bi, Wenzi; Li, Bin; Song, Jiangning; Hong, Youliang; Zhang, Xiaoxiao; Liu, Haiyang; Lu, Hong; Zhou, Tieli; Cao, Jianming

    2017-07-01

    Fosfomycin in combination with various antibiotics represents an excellent clinically efficacious regimen for the treatment of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Underlying mechanisms of fosfomycin resistance remain largely uncharacterised. To investigate the antibacterial efficacy of fosfomycin against ESBL-producing E. coli, 356 non-repetitive ESBL-producing E. coli clinical isolates were collected from urine specimens from patients with UTI in Wenzhou, China, from January 2011 to December 2015. Antimicrobial sensitivity testing indicated that 6.7% (24/356) of the ESBL-producing E. coli strains were resistant to fosfomycin. The fosA3 gene encoding a fosfomycin-modifying enzyme was detected in 20 isolates by PCR and sequencing, alone or in combination with other ESBL determinants. Conjugation experiments and Southern blotting demonstrated that 70% (14/20) of the fosA3-positive isolates possessed transferable plasmids (ca. 54.2 kb) co-harbouring the ESBL resistance gene bla CTX-M and the fosfomycin resistance gene fosA3. Among the four fosfomycin-resistant fosA3-negative E. coli isolates, three contained amino acid substitutions (Ile28Asn and Phe30Leu in MurA and Leu297Phe in GlpT). The results indicate that presence of the fosA3 gene is the primary mechanism of fosfomycin resistance in ESBL-producing E. coli isolates in Wenzhou, China. In addition, a plasmid (ca. 54.2 kb) co-harbouring fosA3 and bla CTX-M genes is horizontally transferable. Furthermore, a low degree of homology in the fosfomycin-resistant E. coli was confirmed using multilocus sequence typing (MLST), suggesting that there is no obvious phenomenon of clonal dissemination. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  3. Purification and characterization of a fibrinolytic enzyme produced from Bacillus sp. strain CK 11-4 screened from Chungkook-Jang.

    Science.gov (United States)

    Kim, W; Choi, K; Kim, Y; Park, H; Choi, J; Lee, Y; Oh, H; Kwon, I; Lee, S

    1996-01-01

    Bacillus sp. strain CK 11-4, which produces a strongly fibrinolytic enzyme, was screened from Chungkook-Jang, a traditional Korean fermented-soybean sauce. The fibrinolytic enzyme (CK) was purified from supernatant of Bacillus sp. strain CK 11-4 culture broth and showed thermophilic, hydrophilic, and strong fibrinolytic activity. The optimum temperature and pH were 70 degrees C and 10.5, respectively, and the molecular weight was 28,200 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first 14 amino acids of the N-terminal sequence of CK are Ala-Gin-Thr-Val-Pro-Tyr-Gly-Ile-Pro-Leu-Ile-Lys-Ala-Asp. This sequence is identical to that of subtilisin Carlsberg and different from that of nattokinase, but CK showed a level of fibrinolytic activity that was about eight times higher than that of subtilisin Carlsberg. The amidolytic activity of CK increased about twofold at the initial state of the reaction when CK enzyme was added to a mixture of plasminogen and substrate (H-D-Val-Leu-Lys-pNA). A similar result was also obtained from fibrin plate analysis. PMID:8779587

  4. Production of Volatile Compounds in Reconstituted Milk Reduced-Fat Cheese and the Physicochemical Properties as Affected by Exopolysaccharide-Producing Strain

    Directory of Open Access Journals (Sweden)

    Weijun Wang

    2012-12-01

    Full Text Available The application of the exopolysaccharide-producing strains for improving the texture and technical properties of reduced-fat cheese looks very promising. Streptococcus thermophilus TM11 was evaluated for production of reduced-fat cheese using reconstituted milk powder (CRMP. The physicochemical analysis of fresh and stored cheeses showed that this strain slightly increased moisture content resulting in cheese with higher yield and lower protein content compared to the direct acidified cheese. The volatiles of cheese were determined by SPME and GC equipped with a mass spectrometer. The results indicated that the major compounds included aldehydes, ketones and acids, whereas, alcohols and branched-chain aldehydes that contribute to exciting and harsh flavors were not found in CRMP. By the textural profile analysis, we found the cheese made with S. thermophilus TM11 had lower cohesiveness, resilience and higher adhesiveness than the direct acidified cheese, and had similar hardness. Further, S. thermophilus TM11 greatly changed the protein matrix with more opened cavities according to observation by scanning electron microscopy. Consequently, use of S. thermophilus TM11 could endow CRMP with the novel and suitable flavor properties and improved texture quality.

  5. Selection of tannase-producing Aspergillus niger strains Seleção de linhagens de Aspergillus niger produtoras de tanase

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    Gustavo A.S. Pinto

    2001-03-01

    Full Text Available The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g-1/72 hours of fermentation.O objetivo deste trabalho foi selecionar linhagens de Aspergillus niger para síntese de tanase. O crescimento das colônias em meio contendo ácido tânico indicou capacidade de produção de tanase. A atividade enzimática foi determinada em fermentação semi-sólida. A. niger 11T25A5 foi o melhor produtor (67.5 U.g-1/72 horas de fermentação.

  6. Immobilization of an L-aminoacylase-producing strain of Aspergillus oryzae into gelatin pellets and its application in the resolution of D,L-methionine.

    Science.gov (United States)

    Yuan Yj, Ying-jin; Wang Sh, Shu-hao; Song Zx, Zheng-xiao; Gao Rc, Rui-chang

    2002-04-01

    The conditions for immobilization of an l-aminoacylase-producing strain of Aspergillus oryzae in gelatin and the enzymic characteristics of the immobilized pellets were studied. The optimal concentrations of gelatin, glutaraldehyde and ethyldiamine and time of immobilization were determined. Scanning electron micrographs reveal the cross-linked structure differences between the native and immobilized pellets. Optimum pH and temperature of the native and immobilized pellets were determined. Effects of ionic strength and substrate concentration on relative activity of the native and immobilized pellets were investigated in detail. The immobilized pellets were more stable over broader temperature and pH ranges. In addition, the immobilized pellets showed stable activity under operational and storage conditions. The immobilized pellets lost about 20% of their initial activity after five cycles of reuse. The results reported in this paper show the potential for using the immobilized A. oryzae pellets to resolve d,l-methionine.

  7. Emergence of extended spectrum beta-lactamases-producing strains belonging to cefotaxime-M-1 class from intensive care units patients and environmental surfaces in Pakistan

    Directory of Open Access Journals (Sweden)

    Aqsa Ashraf Bukhari

    2016-11-01

    Full Text Available Aim: The emergence of multidrug-resistant (MDR bacteria is the most dangerous threat for the treatment of infectious diseases. The aim of this study was to detect and characterize extended spectrum beta-lactamases (ESBLs and carbapenemase-producing Klebsiella pneumoniae and Escherichia coli among patients and environment of intensive care units (ICUs of three tertiary care hospitals in Pakistan. Materials and Methods: A total of 82 samples from ICU’s patients and inanimate environment (injection trays, wash basins, door handles, hand swabs of professionals, and ICU fridges were screened for ESBL by culturing on CHROMagar-ESBL. ESBL and carbapenemases production were confirmed by double disc synergy test and modified Hodge’s test, respectively. Polymerase chain reaction was used to detect ESBL encoding genes bla cefotaxime (CTX-M, blaCTX-M-1, blaCTX-M-2, blaCTX-M-9, blaTEM, blaSHV and carbapenemase genes blaKPC, bla New Delhi metallo-beta-lactamase-1, blaOXA-48 and blaVIM. Results: Overall, ESBL production was found high 30/82 (36.5% among isolates of which 15.8% K. pneumoniae and 20.7% E. coli were identified. All the K. pneumoniae and majority of E. coli isolates were MDR, i.e., resistance to three or more antimicrobial categories. Molecular characterization showed the blaCTX-M-1 as the predominant genotype found in 17/21 (80% of the isolates. None of the strains was found positive for carbapenemase-encoding genes. Conclusion: In conclusion, this study demonstrates the emergence of MDR ESBL producing strains among ICU patients and hospital environment, posing a serious threat for the control of nosocomial infections.

  8. Novel comprehensive multidimensional liquid chromatography approach for elucidation of the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 strain.

    Science.gov (United States)

    Cacciola, Francesco; Mangraviti, Domenica; Rigano, Francesca; Donato, Paola; Dugo, Paola; Mondello, Luigi; Cortes, Hernan J

    2018-06-01

    Shikimic acid is a intermediate of aromatic amino acid biosynthesis and the preferred starting material for production of the most commonly prescribed anti-influenza drug, Tamiflu. Its six-membered carbocyclic ring is adorned with several chiral centers and various functionalities, making shikimic acid a valuable chiral synthon. When microbially-produced, in addition to shikimic acid, numerous other metabolites are exported out of the cytoplasm and accumulate in the culture medium. This extracellular matrix of metabolites is referred to as the microbosphere. Due to the high sample complexity, in this study, the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 was analyzed by liquid chromatography and comprehensive two-dimensional liquid chromatography coupled to photodiode array and mass spectrometry detection. GC analysis of the trimethylsilyl derivatives was also carried out in order to support the elucidation of the selected metabolites in the microbosphere. The elucidation of the metabolic fraction of this bacterial strain might be of valid aid for improving, through genetic changes, the concentration and yield of shikimic acid synthesized from glucose. Graphical abstract.

  9. Effects of curing sodium nitrite additive and natural meat fat on growth control of Listeria monocytogenes by the bacteriocin-producing Lactobacillus curvatus strain CWBI-B28.

    Science.gov (United States)

    Kouakou, P; Ghalfi, H; Destain, J; Dubois-Dauphin, R; Evrard, P; Thonart, P

    2009-09-01

    In realistic model meat systems, the separate and combined effects of fat content and sodium nitrite on the antilisterial activity of the bacteriocin of Lactobacillus curvatus CWBI-B28 were studied. In laboratory fermentations where Listeria monocytogenes was co-cultured at 4 degrees C with bacteriocin-producing CWBI-B28 in lean pork meat (fat content: 13%) without added nitrite, a strong antilisterial effect was observed after one week. The effect was maintained for an additional week, after which a slight and very gradual rebound was observed. Both added nitrite (20 ppm) and a high-fat content (43%) were found to antagonise this antilisterial effect, the Listeria cfu count reached after six weeks being 200 times as high in high-fat meat with added nitrite than in lean meat without nitrite. This antagonism could not be attributed to slower growth of the bacteriocin-producing strain, since CWBI-B28 grew optimally in fat-rich meat with 20 ppm sodium nitrite. Bacteriocin activity was also measured in the samples. The observed activity levels are discussed in relation to the degree of antilisterial protection conferred.

  10. Engineered strains of Streptococcus macedonicus towards an osmotic stress resistant phenotype retain their ability to produce the bacteriocin macedocin under hyperosmotic conditions.

    Science.gov (United States)

    Anastasiou, Rania; Driessche, Gonzalez Van; Boutou, Effrossyni; Kazou, Maria; Alexandraki, Voula; Vorgias, Constantinos E; Devreese, Bart; Tsakalidou, Effie; Papadimitriou, Konstantinos

    2015-10-20

    Streptococcus macedonicus ACA-DC 198 produces the bacteriocin macedocin in milk only under low NaCl concentrations (<1.0%w/v). The thermosensitive plasmid pGh9:ISS1 was employed to generate osmotic stress resistant (osmr) mutants of S. macedonicus. Three osmr mutants showing integration of the vector in unique chromosomal sites were identified and the disrupted loci were characterized. Interestingly, the mutants were able to grow and to produce macedocin at considerably higher concentrations of NaCl compared to the wild-type (up to 4.0%w/v). The production of macedocin under hyperosmotic conditions solely by the osmr mutants was validated by the well diffusion assay and by mass spectrometry analysis. RT-PCR experiments demonstrated that the macedocin biosynthetic regulon was transcribed at high salt concentrations only in the mutants. Mutant osmr3, the most robust mutant, was converted in its markerless derivative (osmr3f). Co-culture of S. macedonicus with spores of Clostridium tyrobutyricum in milk demonstrated that only the osmr3f mutant and not the wild-type inhibited the growth of the spores under hyperosmotic conditions (i.e., 2.5%w/v NaCl) due to the production of macedocin. Our study shows how genetic manipulation of a strain towards a stress resistant phenotype could improve bacteriocin production under conditions of the same stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Exploiting genotypic diversity of 2,4-diacetylphloroglucinol-producing Pseudomonas spp.: characterization of superior root-colonizing P. fluorescens strain Q8r1-96.

    Science.gov (United States)

    Raaijmakers, J M; Weller, D M

    2001-06-01

    The genotypic diversity that occurs in natural populations of antagonistic microorganisms provides an enormous resource for improving biological control of plant diseases. In this study, we determined the diversity of indigenous 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. occurring on roots of wheat grown in a soil naturally suppressive to take-all disease of wheat. Among 101 isolates, 16 different groups were identified by random amplified polymorphic DNA (RAPD) analysis. One RAPD group made up 50% of the total population of DAPG-producing Pseudomonas spp. Both short- and long-term studies indicated that this dominant genotype, exemplified by P. fluorescens Q8r1-96, is highly adapted to the wheat rhizosphere. Q8r1-96 requires a much lower dose (only 10 to 100 CFU seed(-1) or soil(-1)) to establish high rhizosphere population densities (10(7) CFU g of root(-1)) than Q2-87 and 1M1-96, two genotypically different, DAPG-producing P. fluorescens strains. Q8r1-96 maintained a rhizosphere population density of approximately 10(5) CFU g of root(-1) after eight successive growth cycles of wheat in three different, raw virgin soils, whereas populations of Q2-87 and 1M1-96 dropped relatively quickly after five cycles and were not detectable after seven cycles. In short-term studies, strains Q8r1-96, Q2-87, and 1M1-96 did not differ in their ability to suppress take-all. After eight successive growth cycles, however, Q8r1-96 still provided control of take-all to the same level as obtained in the take-all suppressive soil, whereas Q2-87 and 1M1-96 gave no control anymore. Biochemical analyses indicated that the superior rhizosphere competence of Q8r1-96 is not related to in situ DAPG production levels. We postulate that certain rhizobacterial genotypes have evolved a preference for colonization of specific crops. By exploiting diversity of antagonistic rhizobacteria that share a common trait, biological control can be improved significantly.

  12. Detection of ctx-M gene in ESBL-producing E. coli strains isolated from urinary tract infection in Semnan, Iran.

    Science.gov (United States)

    Tabar, Mahbobeh Mohammad; Mirkalantari, Shiva; Amoli, Rabeeh Izadi

    2016-07-01

    The incidence of urinary tract infections caused by Extended-Spectrum Beta Lactamase (ESBL) producing Escherichia coli (E. coli) strains due to long term and overuse of broad-spectrum cephalosporine is on the rise. CTX beta-lactamase type, a broad-spectrum beta-lactamase, has been expanding in many countries. The ctx gene is harbored on a plasmid that is spread between Enterobacteriaceae family, especially in E. coli. The aim of this study was to determine the pattern of antimicrobial resistance and investigate the prevalent ESBL phenotype and the ctx-M gene in E. coli isolated from patients with urinary tract infections (UTI) in Semnan. A cross sectional study was performed on 109 strains of E. coli isolated from the urine culture of patient suffering from a UTI referred to Shafa hospital (Semnan, Iran) during March-July 2015. Antimicrobial susceptibility testing was applied and the prevalence of the ESBL phenotype was confirmed using combination disk. PCR methods were completed for amplification of the bla ctx gene. Data were analyzed using SPSS version 18 software. One hundred ninety samples (4.16%) were identified as E. coli. Twenty one (26.6%) of E. coli were ESBL positive and 73.4% were ESBL negative. There was 100% susceptibility to imipeneme. Twenty (68.97%) out of 29 isolates were positive for the ctx-M gene, as detected by PCR. In urinary tract infections, antibiotic treatment was experimental and detailed information regarding the sensitivity of bacteria in the area can be useful to achieve the best treatment.

  13. Immunization with 60 kD Ro peptide produces different stages of preclinical autoimmunity in a Sjögren's syndrome model among multiple strains of inbred mice.

    Science.gov (United States)

    Kurien, B T; Dsouza, A; Igoe, A; Lee, Y J; Maier-Moore, J S; Gordon, T; Jackson, M; Scofield, R H

    2013-07-01

    Sjögren's syndrome is a chronic illness manifested characteristically by immune injury to the salivary and lacrimal glands, resulting in dry mouth/eyes. Anti-Ro [Sjögren's syndrome antigen A (SSA)] and anti-La [Sjögren's syndrome antigen B (SSB)] autoantibodies are found frequently in Sjögren's subjects as well as in individuals who will go on to develop the disease. Immunization of BALB/c mice with Ro60 peptides results in epitope spreading with anti-Ro and anti-La along with lymphocyte infiltration of salivary glands similar to human Sjögren's. In addition, these animals have poor salivary function/low saliva volume. In this study, we examined whether Ro-peptide immunization produces a Sjögren's-like illness in other strains of mice. BALB/c, DBA-2, PL/J, SJL/J and C57BL/6 mice were immunized with Ro60 peptide-274. Sera from these mice were studied by immunoblot and enzyme-linked immunosorbent assay for autoantibodies. Timed salivary flow was determined after pharmacological stimulation, and salivary glands were examined pathologically. We found that SJL/J mice had no immune response to the peptide from Ro60, while C57BL/6 mice produced antibodies that bound the peptide but had no epitope spreading. PL/J mice had epitope spreading to other structures of Ro60 as well as to La, but like C57BL/6 and SJL/J had no salivary gland lymphocytic infiltration and no decrement of salivary function. DBA-2 and BALB/c mice had infiltration but only BALB/c had decreased salivary function. The immunological processes leading to a Sjögren's-like illness after Ro-peptide immunization were interrupted in a stepwise fashion in these differing mice strains. These data suggest that this is a model of preclinical disease with genetic control for epitope spreading, lymphocytic infiltration and glandular dysfunction. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  14. The Gene tia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells

    Science.gov (United States)

    Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-01-01

    ABSTRACT Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia, previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia, present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli, including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. PMID:28893912

  15. The Gene tia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells.

    Science.gov (United States)

    Bondì, Roslen; Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-12-01

    Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia , previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia , present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli , including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. Copyright © 2017 American Society for Microbiology.

  16. No evidence of the Shiga toxin-producing E. coli O104:H4 outbreak strain or enteroaggregative E. coli (EAEC found in cattle faeces in northern Germany, the hotspot of the 2011 HUS outbreak area

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    Wieler Lothar H

    2011-11-01

    Full Text Available Abstract Background Ruminants, in particular bovines, are the primary reservoir of Shiga toxin-producing E. coli (STEC, but whole genome analyses of the current German ESBL-producing O104:H4 outbreak strain of sequence type (ST 678 showed this strain to be highly similar to enteroaggregative E. coli (EAEC. Strains of the EAEC pathotype are basically adapted to the human host. To clarify whether in contrast to this paradigm, the O104:H4 outbreak strain and/or EAEC may also be able to colonize ruminants, we screened a total of 2.000 colonies from faecal samples of 100 cattle from 34 different farms - all located in the HUS outbreak region of Northern Germany - for genes associated with the O104:H4 HUS outbreak strain (stx2, terD, rfbO104, fliCH4, STEC (stx1, stx2, escV, EAEC (pAA, aggR, astA, and ESBL-production (blaCTX-M, blaTEM, blaSHV. Results The faecal samples contained neither the HUS outbreak strain nor any EAEC. As the current outbreak strain belongs to ST678 and displays an en-teroaggregative and ESBL-producing phenotype, we additionally screened selected strains for ST678 as well as the aggregative adhesion pattern in HEp-2 cells. However, we were unable to find any strains belonging to ST678 or showing an aggregative adhesion pattern. A high percentage of animals (28% shed STEC, corroborating previous knowl-edge and thereby proving the validity of our study. One of the STEC also harboured the LEE pathogenicity island. In addition, eleven animals shed ESBL-producing E. coli. Conclusions While we are aware of the limitations of our survey, our data support the theory, that, in contrast to other Shiga-toxin producing E. coli, cattle are not the reservoir for the O104:H4 outbreak strain or other EAEC, but that the outbreak strain seems to be adapted to humans or might have yet another reservoir, raising new questions about the epidemiology of STEC O104:H4.

  17. Recombinant HA1 produced in E. coli forms functional oligomers and generates strain-specific SRID potency antibodies for pandemic influenza vaccines.

    Science.gov (United States)

    Khurana, Surender; Larkin, Christopher; Verma, Swati; Joshi, Manju B; Fontana, Juan; Steven, Alasdair C; King, Lisa R; Manischewitz, Jody; McCormick, William; Gupta, Rajesh K; Golding, Hana

    2011-08-05

    Vaccine production and initiation of mass vaccination is a key factor in rapid response to new influenza pandemic. During the 2009-2010 H1N1 pandemic, several bottlenecks were identified, including the delayed availability of vaccine potency reagents. Currently, antisera for the single-radial immunodiffusion (SRID) potency assay are generated in sheep immunized repeatedly with HA released and purified after bromelain-treatment of influenza virus grown in eggs. This approach was a major bottleneck for pandemic H1N1 (H1N1pdm09) potency reagent development in 2009. Alternative approaches are needed to make HA immunogens for generation of SRID reagents in the shortest possible time. In this study, we found that properly folded recombinant HA1 globular domain (rHA1) from several type A viruses including H1N1pdm09 and two H5N1 viruses could be produced efficiently using a bacterial expression system and subsequent purification. The rHA1 proteins were shown to form functional oligomers of trimers, similar to virus derived HA, and elicited high titer of neutralizing antibodies in rabbits and sheep. Importantly, the immune sera formed precipitation rings with reference antigens in the SRID assay in a dose-dependent manner. The HA contents in multiple H1N1 vaccine products from different manufacturers (and in several lots) as determined with the rHA1-generated sheep sera were similar to the values obtained with a traditionally generated sheep serum from NIBSC. We conclude that bacterially expressed recombinant HA1 proteins can be produced rapidly and used to generate SRID potency reagents shortly after new influenza strains with pandemic potential are identified. Published by Elsevier Ltd.

  18. Isolation and Characterization of Plantaricin Produced by Lactobacillus plantarum Strains (IIA-1A5, IIA-1B1, IIA-2B2

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    I. I. Arief

    2013-08-01

    Full Text Available Bacteriocins produced by Indonesian lactic acid bacteria Lactobacillus plantarum IIA-1A5, IIA-1B1, IIA-2B2 were purified and characterized. Plantaricin W gene had been successfully amplified from all strains. This amplicon showed the expected 200 bp size of plantaricin W gene. This bacteriocins purified from L. plantarum IIA-1A5, IIA-1B1, and IIA-2B2 were named plantaricin IIA-1A5, IIA-1B1, and IIA-2B2. Purification by cation exchange chromatography increased the purity (fold and activity of plantaricins. Purity of plantaricin IIA-1A5 was increased by 3.13 fold with specific activity 13.40 AU/mg. Plantaricin IIA-1B1 had 2.98 fold purity with specific activity 5.12 AU/mg, while purity of plantaricin IIA-2B2 was 1.37 fold with specific activity 7.70 AU/mg. All plantaricins could inhibit the growth of pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus. Plantaricins could be digested by trypsin. Stability of plantaricins at 80 oC for 30 min and at 121 oC for 15 min were affected by type of plantaricin and species of pathogenic bacteria. Generally, plantaricin IIA-1A5 was better as antimicrobial agent than plantaricin IIA-1B1 and plantaricin IIA-2B2.

  19. Proteomics analysis of high lipid-producing strain Mucor circinelloides WJ11: an explanation for the mechanism of lipid accumulation at the proteomic level.

    Science.gov (United States)

    Tang, Xin; Zan, Xinyi; Zhao, Lina; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda; Ratledge, Colin

    2016-02-11

    The oleaginous fungus, Mucor circinelloides, is attracting considerable interest as it produces oil rich in γ-linolenic acid. Nitrogen (N) deficiency is a common strategy to trigger the lipid accumulation in oleaginous microorganisms. Although a simple pathway from N depletion in the medium to lipid accumulation has been elucidated at the enzymatic level, global changes at protein levels upon N depletion have not been investigated. In this study, we have systematically analyzed the changes at the levels of protein expression in M. circinelloides WJ11, a high lipid-producing strain (36 %, lipid/cell dry weight), during lipid accumulation. Proteomic analysis demonstrated that N depletion increased the expression of glutamine synthetase, involved in ammonia assimilation, for the supply of cellular nitrogen but decreased the metabolism of amino acids. Upon N deficiency, many proteins (e.g., fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase) involved in glycolytic pathway were up-regulated while proteins involved in the tricarboxylic acid cycle (e.g., isocitrate dehydrogenase, succinyl-CoA ligase, succinate dehydrogenase, fumarate hydratase) were down-regulated, indicating this activity was retarded thereby leading to a greater flux of carbon into fatty acid biosynthesis. Moreover, glucose-6-phosphate dehydrogenase, transaldolase and transketolase, which participate in the pentose phosphate pathway, were up-regulated, leading to the increased production of NADPH, the reducing power for fatty acid biosynthesis. Furthermore, protein and nucleic acid metabolism were down-regulated and some proteins involved in energy metabolism, signal transduction, molecular chaperone and redox homeostasis were up-regulated upon N depletion, which may be the cellular response to the stress produced by the onset of N deficiency. N limitation increased those expressions of the proteins involved in ammonia assimilation but decreased that

  20. Escherichia coli Probiotic Strain ED1a in Pigs Has a Limited Impact on the Gut Carriage of Extended-Spectrum-β-Lactamase-Producing E. coli

    Science.gov (United States)

    Mourand, G.; Paboeuf, F.; Fleury, M. A.; Jouy, E.; Bougeard, S.; Denamur, E.

    2016-01-01

    ABSTRACT Four trials were conducted to evaluate the impact of Escherichia coli probiotic strain ED1a administration to pigs on the gut carriage or survival in manure of extended-spectrum-β-lactamase-producing E. coli. Groups of pigs were orally inoculated with strain E. coli M63 carrying the blaCTX-M-1 gene (n = 84) or used as a control (n = 26). In the first two trials, 24 of 40 E. coli M63-inoculated pigs were given E. coli ED1a orally for 6 days starting 8 days after oral inoculation. In the third trial, 10 E. coli M63-inoculated pigs were given either E. coli ED1a or probiotic E. coli Nissle 1917 for 5 days. In the fourth trial, E. coli ED1a was given to a sow and its 12 piglets, and these 12 piglets plus 12 piglets that had not received E. coli ED1a were then inoculated with E. coli M63. Fecal shedding of cefotaxime-resistant Enterobacteriaceae (CTX-RE) was studied by culture, and blaCTX-M-1 genes were quantified by PCR. The persistence of CTX-RE in manure samples from inoculated pigs or manure samples inoculated in vitro with E. coli M63 with or without probiotics was studied. The results showed that E. coli M63 and ED1a were good gut colonizers. The reduction in the level of fecal excretion of CTX-RE in E. coli ED1a-treated pigs compared to that in nontreated pigs was usually less than 1 log10 CFU and was mainly observed during the probiotic administration period. The results obtained with E. coli Nissle 1917 did not differ significantly from those obtained with E. coli ED1a. CTX-RE survival did not differ significantly in manure samples with or without probiotic treatment. In conclusion, under our experimental conditions, E. coli ED1a and E. coli Nissle 1917 could not durably prevent CTX-RE colonization of the pig gut. PMID:27795372

  1. Escherichia coli Probiotic Strain ED1a in Pigs Has a Limited Impact on the Gut Carriage of Extended-Spectrum-β-Lactamase-Producing E. coli.

    Science.gov (United States)

    Mourand, G; Paboeuf, F; Fleury, M A; Jouy, E; Bougeard, S; Denamur, E; Kempf, I

    2017-01-01

    Four trials were conducted to evaluate the impact of Escherichia coli probiotic strain ED1a administration to pigs on the gut carriage or survival in manure of extended-spectrum-β-lactamase-producing E. coli Groups of pigs were orally inoculated with strain E. coli M63 carrying the bla CTX-M-1 gene (n = 84) or used as a control (n = 26). In the first two trials, 24 of 40 E. coli M63-inoculated pigs were given E. coli ED1a orally for 6 days starting 8 days after oral inoculation. In the third trial, 10 E. coli M63-inoculated pigs were given either E. coli ED1a or probiotic E. coli Nissle 1917 for 5 days. In the fourth trial, E. coli ED1a was given to a sow and its 12 piglets, and these 12 piglets plus 12 piglets that had not received E. coli ED1a were then inoculated with E. coli M63. Fecal shedding of cefotaxime-resistant Enterobacteriaceae (CTX-RE) was studied by culture, and bla CTX-M-1 genes were quantified by PCR. The persistence of CTX-RE in manure samples from inoculated pigs or manure samples inoculated in vitro with E. coli M63 with or without probiotics was studied. The results showed that E. coli M63 and ED1a were good gut colonizers. The reduction in the level of fecal excretion of CTX-RE in E. coli ED1a-treated pigs compared to that in nontreated pigs was usually less than 1 log 10 CFU and was mainly observed during the probiotic administration period. The results obtained with E. coli Nissle 1917 did not differ significantly from those obtained with E. coli ED1a. CTX-RE survival did not differ significantly in manure samples with or without probiotic treatment. In conclusion, under our experimental conditions, E. coli ED1a and E. coli Nissle 1917 could not durably prevent CTX-RE colonization of the pig gut. Copyright © 2016 American Society for Microbiology.

  2. Safety characterisation and inhibition of fungi and bacteria by a novel multiple enterocin-producing Enterococcus lactis 4CP3 strain.

    Science.gov (United States)

    Ben Braïek, Olfa; Cremonesi, Paola; Morandi, Stefano; Smaoui, Slim; Hani, Khaled; Ghrairi, Taoufik

    2018-03-07

    This study aims to characterise a potential bacteriocinogenic lactic acid bacterial strain isolated from a raw pink shrimp (Palaemon serratus) and evaluate its safety aspect. The strain designated as 4CP3 was noted to display antibacterial activities (P enterocins A, B and P. To our knowledge, this feature is newly described for E. lactis strain isolated from raw shrimps. Regarding safety aspect of E. lactis 4CP3, it has been demonstrated that this strain was not haemolytic, gelatinase negative, sensitive to vancomycin, and free of common antibiotic resistance genes and virulence factors. Therefore, it may be useful as a safe natural agent in preservation of foods or as a new probiotic strain in food and feed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Enhanced biodegradation of lindane using oil-in-water bio-microemulsion stabilized by biosurfactant produced by a new yeast strain, Pseudozyma VITJzN01.

    Science.gov (United States)

    Abdul Salam, Jaseetha; Das, Nilanjana

    2013-11-28

    Organochlorine pesticide residues continue to remain as a major environmental threat worldwide. Lindane is an organochlorine pesticide widely used as an acaricide in medicine and agriculture. In the present study, a new lindane-degrading yeast strain, Pseudozyma VITJzN01, was identified as a copious producer of glycolipid biosurfactant. The glycolipid structure and type were elucidated by FTIR, NMR spectroscopy, and GC-MS analysis. The surface activity and stability of the glycolipid was analyzed. The glycolipids, characterized as mannosylerythritol lipids (MELs), exhibited excellent surface active properties and the surface tension of water was reduced to 29 mN/m. The glycolipid was stable over a wide range of pH, temperature, and salinity, showing a very low CMC of 25 mg/l. Bio-microemulsion of olive oil-in-water (O/W) was prepared using the purified biosurfactant without addition of any synthetic cosurfactants, for lindane solubilization and enhanced degradation assay in liquid and soil slurry. The O/W bio-microemulsions enhanced the solubility of lindane up to 40-folds. Degradation of lindane (700 mg/l) by VITJzN01 in liquid medium amended with bio-microemulsions was found to be enhanced by 36% in 2 days, compared with degradation in 12 days in the absence of bio-microemulsions. Lindane-spiked soil slurry incubated with bio-microemulsions also showed 20-40% enhanced degradation compared with the treatment with glycolipids or yeast alone. This is the first report on lindane degradation by Pseudozyma sp., and application of bio-microemulsions for enhanced lindane degradation. MEL-stabilized bio-microemulsions can serve as a potential tool for enhanced remediation of diverse lindanecontaminated environments.

  4. Construction of a Recombinant Allergen-Producing Probiotic Bacterial Strain: Introduction of a New Line for a Live Oral Vaccine Against Chenopodium album Pollen Allergy

    Directory of Open Access Journals (Sweden)

    Leila Roozbeh Nasiraie

    2013-10-01

    Full Text Available Background: During the last two decades, significant advances have been made in the fields of lactococcal genetics and protein expression. Lactococcus lactis (L. lactis is an effective vector for protein expression and can be used as an antigen delivery system. Hence, L. lactis is an ideal candidate for mucosal immunotherapy. Profilin (Che a 2, the major allergen in Chenopodium album, is one of the most important causes of allergic diseases in desert and semi-desert areas, especially in Iran, Saudi Arabia, and Kuwait that was cloned and expressed in L. lactis for the first time. Methods: To construct L. lactis that expressed Che a 2, a DNA sequence was cloned and used to transform bacteria. Expression of Che a 2 was analyzed via monitoring of related RNA and protein. Hydrophobicity, adherence to HT-29 cells, antibiotic resistance, resistance to gastrointestinal contents, pH, and bile salt in recombinant and native L. lactis were evaluated. Results: Immunoblot analyses demonstrated that recombinant Che a 2 is expressed as a 32 kDa dimeric protein immunological studies showed it can bind human IgE. Both native and recombinant bacteria were sensitive to low pH and simulated gastric conditions. Bacterial survival was reduced 80-100% after 2 h of exposure to pH 1.5-2. Both native and recombinant bacteria were able to grow in 0.3 and 2% bile salts. After incubation of recombinant L. lactis in simulated gastric and intestinal juices for one and two hours, respectively, cell survival was reduced by 100%. Adhesion capability in both strains was minimal and there were no significant differences in any of our tests between native and recombinant bacteria. Conclusion: Successfully recombinant L. lactis with capability of expression Che a 2 was produced and revealed it is sensitive to gastrointestinal contents.

  5. Characterization of biosurfactants produced by novel strains of Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2 from used engine oil-contaminated soil

    Directory of Open Access Journals (Sweden)

    Haytham M.M. Ibrahim

    2018-03-01

    Full Text Available Microbial surfactants are widely used for industrial, agricultural, food, cosmetics, pharmaceutical, and medical applications. In this study, two bacterial strains namely, Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2, previously isolated from used engine oil contaminated soil, and capable of producing biosurfactants, were used. Their cell-free culture broth showed positive results toward five screening tests (hemolysis in blood agar, drop collapse, oil displacement, emulsification activity (E24, and surface tension (ST reduction. They reduced the ST of growth medium (70 ± 0.9 to 30.8 ± 0.6 and 32.5 ± 1.3 mN/m, respectively. The biosurfactants were classified as anionic biomolecules. Based on TLC pattern and FT-IR analysis, they were designated as glycolipids (rhamnolipid. Waste frying oil was feasibly used as a cheap and dominant carbon source for biosurfactants production; 4.9 and 4.1 g/l were obtained after 96 h of incubation, respectively. Compared with non-irradiated cells, gamma-irradiated cells (1.5 kGy revealed enhanced biosurfactant production by 56 and 49% for HM-1 and HM-2, respectively. The biosurfactants showed good stability after exposure to extreme conditions [temperatures (50–100 °C for 30 min, pH (2–12 and salinity (2–10% NaCl], they retained 83 and 79.3% of their E24, respectively, after incubation for a month, under extreme conditions. Biosurfactants effectively recovered up to 70 and 67% of the residual oil, respectively, from oil-saturated sand pack columns. These biosurfactants are an interesting biotechnological product for many environmental and industrial applications. Keywords: Ochrobactrum anthropi, Citrobacter freundii, Biosurfactant, Characterization, Stability

  6. Fluorescent amplified fragment length polymorphism (FAFLP genotyping demonstrates the role of biofilm-producing methicillin-resistant periocular Staphylococcus epidermidis strains in postoperative endophthalmitis

    Directory of Open Access Journals (Sweden)

    Hasnain Seyed E

    2006-01-01

    Full Text Available Abstract Background An observational case series was used to study the virulence characteristics and genotypes of paired Staphylococcus epidermidis isolates cultured from intraocular samples and from periocular environment of patients with postcataract surgery endophthalmitis. Methods Eight S. epidermidis isolates were obtained from three patients (2 from patients #1 and 2 and 4 from patient #3 whose vitreous and/or anterior chamber (AC specimens and preoperative lid/conjunctiva samples were culture positive. Cultures were identified by API-Staph phenotypic identification system and genotypically characterized by Fluorescent Amplified Fragment Length Polymorphism (FAFLP and checked for their antimicrobial susceptibility. The isolates were tested for biofilm-production and methicillin-resistance (MR by PCR amplification of icaAB and mecA gene respectively. Results Four out of eight S. epidermidis strains showed multiple drug resistance (MDR. All the eight strains were PCR positive for mecA gene whereas seven out of eight strains were positive for icaAB genes. In all three patients FAFLP typing established vitreous isolates of S. epidermidis strains to be indistinguishable from the strains isolated from the patient's conjunctival swabs. However, from patient number three there was one isolate (1030b from lid swab, which appeared to be nonpathogenic and ancestral having minor but significant differences from other three strains from the same patient. This strain also lacked icaAB gene. In silico analysis indicated possible evolution of other strains from this strain in the patient. Conclusion Methicillin-resistant biofilm positive S. epidermidis strains colonizing the conjunctiva and eyelid were responsible for postoperative endophthalmitis (POE.

  7. Draft Genome Sequence of Sphingomonas sp. Strain Sph1(2015), Isolated from a Fouled Membrane Filter Used To Produce Drinking Water.

    Science.gov (United States)

    de Vries, Hendrik J; Marshall, Ian P G; Schreiber, Lars; Plugge, Caroline M

    2017-06-15

    We report here the high-quality draft genome sequence of Sphingomonas sp. strain Sph1(2015), isolated from a fouled reverse osmosis membrane used for the production of high-quality drinking water. The draft sequence provides insights into the modus operandi of this strain to form biofilms on membrane surfaces. This knowledge offers tools to develop novel antifouling strategies. Copyright © 2017 de Vries et al.

  8. Fate of acid-resistant and non-acid resistant Shiga toxin-producing Escherichia coli strains in experimentally contaminated French fermented raw meat sausages.

    Science.gov (United States)

    Montet, M P; Christieans, S; Thevenot, D; Coppet, V; Ganet, S; Muller, M L Delignette; Dunière, L; Miszczycha, S; Vernozy-Rozand, C

    2009-02-28

    Both pathogenic and nonpathogenic E. coli exhibit a stress response to sublethal environmental stresses. Several studies have reported acid tolerance and survival characteristics of E. coli O157:H7 in foodstuffs, but there are few reports about the tolerance of non-O157 serogroups (STEC) to organic acids in foods. The purpose of this study was to examine the effect of the manufacturing process of French fermented raw meat sausages on the growth and survival of acid-resistant (AR) and non-acid resistant (NAR) STEC strains. The six strains, 3 AR and 3 NAR, were inoculated separately into raw sausage mixture at a level of 10(4)-10(5) CFU/g. A total of 19 batches of sausages were manufactured. A rapid and similar decrease in the number of both AR and NAR STEC strains, from less than 1 to 1.5 log(10) CFU/g, was observed during the first 5 days of fermentation at 20-24 degrees C. This rapid decrease was followed by a more gradual but continuous decrease in STEC counts after drying at 13-14 degrees C, up to day 35. The STEC counts were <10 CFU/g after 35 days for the NAR strains and the same concentration for the AR strains on the best before date (day 60). It was not possible to detect any NAR STEC after 60 days. The present study shows that the process used in the manufacture of French sausages results in a complete destruction of NAR STEC strains after 60 days, but it does not have the same effect on the AR STEC strains.

  9. The effect of bacteriocin-producing Lactobacillus plantarum strains on the intracellular pH of sessile and planktonic Listeria monocytongenes single cells

    DEFF Research Database (Denmark)

    Nielsen, Dennis Sandris; Cho, Gyu-Sung; Hanak, Alexander

    2010-01-01

    and/or bacteriocin-producing LAB as “natural” food preservatives in foods such as cheese, meat and ready-to-eat products. Some strains of Lactobacillus plantarum produce bacteriocins termed plantaricins. Using a single-cell based approach, the effect on the intracellular pH as a measure......A wide range of lactic acid bacteria (LAB) produce bacteriocins mainly active against other closely related LAB, but some bacteriocins are also active against the food-borne pathogen Listeria monocytogenes. With the aim of increasing food safety it has thus been considered to utilise bacteriocins...

  10. Characterization of a Wild, Novel Nisin A-Producing Lactococcus Strain with an L. lactis subsp. cremoris Genotype and an L. lactis subsp. lactis Phenotype, Isolated from Greek Raw Milk

    Science.gov (United States)

    Parapouli, Maria; Delbès-Paus, Céline; Kakouri, Athanasia; Koukkou, Anna-Irini; Montel, Marie-Christine

    2013-01-01

    Several molecular taxonomic studies have revealed that many natural (wild) Lactococcus lactis strains of dairy origin which are phenotypically representative of the L. lactis subspecies lactis cluster genotypically within subspecies cremoris and vice versa. Recently, we isolated two wild nisin-producing (Nis+) L. lactis strains, M78 and M104, of the lactis phenotype from Greek raw milk (J. Samelis, A. Lianou, A. Kakouri, C. Delbès, I. Rogelj, B. B. Matijašic, and M. C. Montel, J. Food Prot. 72:783–790, 2009); strain M78 possess a novel nisin A sequence (GenBank accession number HM219853). In this study, the actual subspecies identity of M78 and M104 isolates was elucidated, using 16S rRNA and acmA (encoding lactococcal N-acetylmuramidase) gene and histidine biosynthesis operon polymorphisms and 16S rRNA and ldh (encoding lactate dehydrogenase) gene phylogenies. Except the acmA gene analysis, molecular tools revealed that isolates M78 and M104 clustered with strains of the cremoris genotype, including the LMG 6897T strain, while they were distant from strains of the lactis genotype, including the LMG 6890T strain. The two wild isolates had identical repetitive sequence-based PCR (rep-PCR), randomly amplified polymorphic DNA (RAPD), plasmid, and whole-cell protein profiles and shared high 16S rRNA (99.9%) and ldh (100%) gene sequence homologies. In contrast, they exhibited identical sugar fermentation and enzymatic patterns which were similar to those of the subspecies lactis LMG 6890T strain. To our knowledge, this is the first complete identification report on a wild L. lactis subsp. cremoris genotype of the lactis phenotype which is capable of nisin A production and, thus, has strong potential for use as a novel dairy starter and/or protective culture. PMID:23542625

  11. Fermentative capabilities and volatile compounds produced by Kloeckera/Hanseniaspora and Saccharomyces yeast strains in pure and mixed cultures during Agave tequilana juice fermentation.

    Science.gov (United States)

    González-Robles, Ivonne Wendolyne; Estarrón-Espinosa, Mirna; Díaz-Montaño, Dulce María

    2015-09-01

    The fermentative and aromatic capabilities of Kloeckera africana/Hanseniaspora vineae K1, K. apiculata/H. uvarum K2, and Saccharomyces cerevisiae S1 and S2 were studied in pure and mixed culture fermentations using Agave tequila juice as the culture medium. In pure and mixed cultures, Kloeckera/Hanseniaspora strains showed limited growth and sugar consumption, as well as low ethanol yield and productivity, compared to S. cerevisiae, which yielded more biomass, ethanol and viable cell concentrations. In pure and mixed cultures, S. cerevisiae presented a similar behaviour reaching high biomass production, completely consuming the sugar, leading to high ethanol production. Furthermore, the presence of S. cerevisiae strains in the mixed cultures promoted the production of higher alcohols, acetaldehyde and ethyl esters, whereas Kloeckera/Hanseniaspora strains stimulated the production of ethyl acetate and 2-phenyl ethyl acetate compounds.

  12. The new allelic variant of the subtilase cytotoxin (subAB2) is common among Shiga toxin-producing Escherichia coli strains from large game animals and their meat and meat products.

    Science.gov (United States)

    Sánchez, Sergio; Díaz-Sánchez, Sandra; Martínez, Remigio; Llorente, María Teresa; Herrera-León, Silvia; Vidal, Dolors

    2013-10-25

    Subtilase cytotoxin (SubAB) is an AB5 toxin produced by Shiga toxin (Stx)-producing Escherichia coli (STEC) strains usually lacking the eae gene product intimin. Two allelic variants of SubAB encoding genes have been described: subAB1, located on a plasmid, and subAB2, located on a pathogenicity island (PAI) together with tia gene. While subAB1 has been reported to be more frequent among bovine strains, subAB2 has been mainly associated with strains from small ruminants. We investigated the presence of the two variants of subAB among 59 eae-negative STEC from large game animals (deer and wild boar) and their meat and meat products in order to assess the role of other species in the epidemiology of subAB-positive, eae-negative STEC. For this approach, the strains were PCR-screened for the presence of subAB, including the specific detection of both allelic variants, for the presence of saa, tia and sab, and for stx subtyping. Overall, subAB genes were detected in 71.2% of the strains: 84.1% of the strains from deer and 33.3% of the strains from wild boar. Most of them (97.6%) possessed subAB2 and most of these subAB2-positive strains (92.7%) were also positive for tia and negative for saa, suggesting the presence of the subAB2-harbouring PAI. Subtype stx2b was present in most of the strains (67.8%) and a statistically significant association could be established between subAB2 and stx2b. Our results suggest that large game animals, mainly deer, may represent an important animal reservoir of subAB2-positive, eae-negative STEC, and also highlight the risk of human infection posed by the consumption of large game meat and meat products. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Solid state fermentation of carinata (Brassica carinata) meal using various fungal strains to produce a protein-rich product for feed application

    Science.gov (United States)

    In this study, the efficacy of several fungal strains to reduce GLS (GLS) content and enhance protein content during solid state fermentation (SSF) of carinata meal was evaluated. Solid state fermentation of hexane extracted (HE) and cold pressed (CP) carinata meals were performed at 50% moisture co...

  14. Improvement of antifungal and antibacterial antibiotic producing strain of Bacillus subtilis AFCI-69 by radiation and chemical mutagens. Part of a coordinated programme on radiation biology

    International Nuclear Information System (INIS)

    Ahmad, M.S.

    1978-08-01

    Gamma radiation was used to select higher antibiotic yield mutants of Bacillus subtilis AECL 69. The test organisms were Aspergillus niger RAGENI 70 and Staphylococcus aureus 6571 (16) N.C.T.C. Searches for fermentation, purification and characterization of antibiotics of parent strain and its mutants were carried out

  15. Biotechnological methods for chalcone reduction using whole cells of Lactobacillus, Rhodococcus and Rhodotorula strains as a way to produce new derivatives.

    Science.gov (United States)

    Stompor, Monika; Kałużny, Mateusz; Żarowska, Barbara

    2016-10-01

    Microbial strains of the genera Dietzia, Micrococcus, Pseudomonas, Rhodococcus, Gordonia, Streptomyces, Pseudomonas, Bacillus, Penicillium, Rhodotorula and Lactobacillus were screened for the ability to convert chalcones. Synthesis of chalcones was performed by the Claisen-Schmidt reaction. There were three groups of chalcones obtained as the products, which included the derivatives containing 4-substituted chalcone, 2'-hydroxychalcone and 4'-methoxychalcone. The B ring of the chalcones was substituted in the para position with different groups, such as halide, hydroxyl, nitro, methyl, ethyl and ethoxy one. The structure-activity relationship of the tested chalcones in biotransformation processes was studied. It has been proven that Gram-positive bacterial strains Rhodococcus and Lactobacillus catalyzed reduction of C=C bond in the chalcones to give respective dihydrochalcones. The strain Rhodotorula rubra AM 82 transformed chalcones into dihydrochalcones and respective secondary alcohols. These results suggest that the probiotic strain of Lactobacillus can be used for biotransformations of chalcones, which has not been described before. The structure of new metabolites 14a and 15b were established as 4-ethoxy-4'-methoxydihydrochalcone and 3-(4-bromophenyl)-1-(4'-O-methylphenyl)-2-propan-1-ol, respectively, which was confirmed by (1)H NMR and (13)C NMR analysis.

  16. The Regulation of Expression of the Stx2d Toxins in Shiga Toxin-producing Escherichia coli O91:H21 Strain B2F1

    Science.gov (United States)

    2002-01-01

    done by Edda Twiddy). The mutants were also transduced with bacteriophage 933W to assess cytotoxicity in the DH5α mutants of a related toxin gene in...amounts of toxin antigen produced by DH5α with the levels produced by the mutants (with the assistance of Edda Twiddy). Dot blots were 84

  17. Chemometric analysis of in-line multi-wavelength fluorescence measurements obtained during cultivations with a lipase producing Aspergillus oryzae strain

    DEFF Research Database (Denmark)

    Haack, Martin Brian; Eliasson Lantz, Anna; Mortensen, P.P.

    2007-01-01

    The filamentous fungus, Aspergillus oryzae, was cultivated in batch and fed-batch cultivations in order to investigate the use of multi-wavelength fluorescence for monitoring course of events during filamentous fungi cultivations. The A. oryzae strain applied expressed a fungal lipase from...... Thermomyces lanuginosus. Spectra of multi-wavelength fluorescence were collected every 5 min with the BioView system (DELTA, Denmark) and both explorative and predictive models, correlating the fluorescence data with cell mass and lipase activity, were built. During the cultivations, A. oryzae displayed...

  18. EFSA Panel on Biological Hazards (BIOHAZ); Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals

    DEFF Research Database (Denmark)

    Hald, Tine; Baggesen, Dorte Lau

    The potential contribution of food-producing animals or foods to public health risks by ESBL and/or AmpC-producing bacteria is related to specific plasmid-mediated ESBL and/or AmpC genes encoded by a number of organisms. The predominant ESBL families encountered are CTX-M, TEM, and SHV...... commonly identified with these genes are Escherichia coli and non-typhoidal Salmonella. ESBL/AmpC transmission is mainly driven by integrons, insertion sequences, transposons and plasmids, some of which are homologous in isolates from both food-production animals and humans. Cefotaxime is used as the drug...... of choice for optimum detection of blaESBL and/or blaAmpC genes. The preferred method for isolation of ESBL- and/or AmpC-producers is screening on selective agar preceded by selective enrichment in a broth.The establishment of risk factors for occurrence of ESBL/AmpC-producing bacteria is particularly...

  19. First complete genome sequence of a species in the genus Microterricola, an extremophilic cold active enzyme producing bacterial strain ERGS5:02 isolated from Sikkim Himalaya.

    Science.gov (United States)

    Himanshu; Swarnkar, Mohit Kumar; Singh, Dharam; Kumar, Rakshak

    2016-03-20

    Here, we report the first ever complete genome sequence of any species in the genus Microterricola. The bacterium Microterricola viridarii ERGS5:02 isolated from the glacial stream of Sikkim Himalaya survived at low temperature and exhibited enhanced growth upon UV treatment, in addition, it also produced cold active enzymes. The complete genome assembly of 3.7 Mb suggested for the presence of genetic elements favoring the survival of bacterium under extreme conditions of UV and low temperature besides producing amylase, lipase and protease of industrial relevance. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. CRISPR/Cas9-mediated targeting of the Rosa26 locus produces Cre reporter rat strains for monitoring Cre-loxP-mediated lineage tracing.

    Science.gov (United States)

    Ma, Yuanwu; Yu, Lei; Pan, Shuo; Gao, Shan; Chen, Wei; Zhang, Xu; Dong, Wei; Li, Jing; Zhou, Rui; Huang, Lan; Han, Yunlin; Bai, Lin; Zhang, Li; Zhang, Lianfeng

    2017-10-01

    The rat is an important laboratory animal for physiological, toxicological and pharmacological studies. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) is a simple and efficient tool to generate precise genetic modifications in rats, which will promote the accumulation of genetic resources and enable more precise studies of gene function. To monitor Cre-loxP-mediated excision in vivo, we generated a Cre reporter rat strain (Rosa26-imCherry) by knockin of a Cre reporter cassette at the Rosa26 locus using CRISPR/Cas9. Rosa26-imCherry rats exhibited inducible expression of the mCherry cassette (imCherry) using the Cre-loxP system, whereas normal rats exhibited ubiquitous expression of eGFP but not mCherry in the whole body. Injection of adeno-associated virus serotype 9-Cre into the hippocampus and skeletal muscle resulted in mCherry expression in virus-infected cells. Cre-loxP-mediated mCherry expression was then evaluated by crossing Rosa26-imCherry rats with transgenic rats ubiquitously expressing CAG-Cre, heart-specific α-MHC-Cre transgenic rats and liver-specific Alb-Cre knockin rats. Finally, using the established system the expression pattern of Cre driven by two endogenous gene promoters (Wfs1-Cre knockin rat, FabP2-Cre knockin rat) was traced. In summary, we demonstrated excision of the loxP-flanked allele in Rosa26-imCherry rats via activation of mCherry expression in the presence of Cre recombinase. This newly established Rosa26-imCherry rat strain represents a useful tool to facilitate Cre-expression pattern determination and tracing experiments. © 2017 Federation of European Biochemical Societies.

  1. Genome sequence of the thermophilic strain Bacillus coagulans 2-6, an efficient producer of high-optical-purity L-lactic acid.

    Science.gov (United States)

    Su, Fei; Yu, Bo; Sun, Jibin; Ou, Hong-Yu; Zhao, Bo; Wang, Limin; Qin, Jiayang; Tang, Hongzhi; Tao, Fei; Jarek, Michael; Scharfe, Maren; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

    2011-09-01

    Bacillus coagulans 2-6 is an efficient producer of lactic acid. The genome of B. coagulans 2-6 has the smallest genome among the members of the genus Bacillus known to date. The frameshift mutation at the start of the d-lactate dehydrogenase sequence might be responsible for the production of high-optical-purity l-lactic acid.

  2. Creation of the technology and man's gen-engineering insulin extraction (GEIE) on the basis of high productive strain - GEIE producent

    International Nuclear Information System (INIS)

    Kosinov, A.; Kotelnikova, O.

    1996-01-01

    Main problems which should be solved: - To create the new highly productive recombinant GENI stain-producer - To select the medium and cultivation's conditions for stain-producer. - To elaborate the separation and purification GENI technology. In order to create the new GENI stain-producer we need significantly change the separation and purification's technology which was elaborated according to traditional method before. The separation and purification GENI's technology demand the industrial methods utilization, such as: ultrafiltration, high-and-low pressures chromatography. Besides, the utilization of recombinant micro-organisms, required for to obtain the medicinal preparations, places a constraint on the quality controls ready made product which should be in conformity with following conditions: high trustworthiness, reproducibility and sensitivity. In this connection, we need to perform a series of the work concerning with analytic controls methods of production and substance preparations technology. To create the separation and purification GENt technology on the highly productive recombinant GENI Stain-producers base. To put in an application in order to patient this new stain. The results of these works will be base for to prepare the normative-technical documents concerning with GENI substances production. Also, we will make the initial data and plan required for to project the GENI substances production. This work will be performed without foreign partner's participation

  3. Exploiting genotypic diversity of 2,4-Diacetylphloroglucinol-producing Pseudomonas spp.: characterization of superior root-colonizing P. fluorescens strain Q8r1-96

    NARCIS (Netherlands)

    Raaijmakers, J.M.; Weller, D.M.

    2001-01-01

    The genotypic diversity that occurs in natural populations of antagonistic microorganisms provides an enormous resource for improving biological control of plant diseases. In this study, we determined the diversity of indigenous 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. occurring

  4. Decolorization of the azo dye Acid Orange 51 by laccase produced in solid culture of a newly isolated Trametes trogii strain

    OpenAIRE

    Daâssi, Dalel; Zouari-Mechichi, Héla; Frikha, Fakher; Martínez, María Jesús; Nasri, M.; Mechichi, Tahar

    2013-01-01

    This study concerns the decolorization and detoxification of the azo dye Acid Orange 51 (AO51) by crude laccase from Trametes trogii produced in solid culture using sawdust as support media. A three-level Box?Behnken factorial design with four factors (enzyme concentration, 1-hydroxybenzotriazole (HBT) concentration, dye concentration and reaction time) combined with response surface methodology was applied to optimize AO51 decolorization. A mathematical model was developed showing the effect...

  5. Utilisation of ISA Reverse Genetics and Large-Scale Random Codon Re-Encoding to Produce Attenuated Strains of Tick-Borne Encephalitis Virus within Days.

    Science.gov (United States)

    de Fabritus, Lauriane; Nougairède, Antoine; Aubry, Fabien; Gould, Ernest A; de Lamballerie, Xavier

    2016-01-01

    Large-scale codon re-encoding is a new method of attenuating RNA viruses. However, the use of infectious clones to generate attenuated viruses has inherent technical problems. We previously developed a bacterium-free reverse genetics protocol, designated ISA, and now combined it with large-scale random codon-re-encoding method to produce attenuated tick-borne encephalitis virus (TBEV), a pathogenic flavivirus which causes febrile illness and encephalitis in humans. We produced wild-type (WT) and two re-encoded TBEVs, containing 273 or 273+284 synonymous mutations in the NS5 and NS5+NS3 coding regions respectively. Both re-encoded viruses were attenuated when compared with WT virus using a laboratory mouse model and the relative level of attenuation increased with the degree of re-encoding. Moreover, all infected animals produced neutralizing antibodies. This novel, rapid and efficient approach to engineering attenuated viruses could potentially expedite the development of safe and effective new-generation live attenuated vaccines.

  6. Phytase-producing capacity of yeasts isolated from traditional African fermented food products and PHYPk gene expression of Pichia kudriavzevii strains.

    Science.gov (United States)

    Greppi, Anna; Krych, Łukasz; Costantini, Antonella; Rantsiou, Kalliopi; Hounhouigan, D Joseph; Arneborg, Nils; Cocolin, Luca; Jespersen, Lene

    2015-07-16

    Phytate is known as a strong chelate of minerals causing their reduced uptake by the human intestine. Ninety-three yeast isolates from traditional African fermented food products, belonging to nine species (Pichia kudriavzevii, Saccharomyces cerevisiae, Clavispora lusitaniae, Kluyveromyces marxianus, Millerozyma farinosa, Candida glabrata, Wickerhamomyces anomalus, Hanseniaspora guilliermondii and Debaryomyces nepalensis) were screened for phytase production on solid and liquid media. 95% were able to grow in the presence of phytate as sole phosphate source, P. kudriavzevii being the best growing species. A phytase coding gene of P. kudriavzevii (PHYPk) was identified and its expression was studied during growth by RT-qPCR. The expression level of PHYPk was significantly higher in phytate-medium, compared to phosphate-medium. In phytate-medium expression was seen in the lag phase. Significant differences in gene expression were detected among the strains as well as between the media. A correlation was found between the PHYPk expression and phytase extracellular activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Identification of an antifungal metabolite produced by a potential biocontrol Actinomyces strain A01 Identificação de um metabólito antifúngico produzido pela cepa Actinomyces A01

    Directory of Open Access Journals (Sweden)

    Cai Ge Lu

    2008-12-01

    Full Text Available Actinomyces strain A01 was isolated from soil of a vegetable field in the suburb of Beijing, China. According to the morphological, cultural, physiological and biochemical characteristics, and 16S rDNA sequence analysis, strain A01 was identified as Streptomyces lydicus. In the antimicrobial spectrum test strain A01 presented a stable and strong inhibitory activity against several plant pathogenic fungi such as Fusarium oxysporum, Botrytis cinerea, Monilinia laxa, etc. However, no antibacterial activity was found. In pot experiments in greenhouse, the development of tomato gray mold was markedly suppressed by treatment with the fermentation broth of the strain A01, and the control efficacy was higher than those of Pyrimethanil and Polyoxin. A main antifungal compound (purity 99.503% was obtained from the fermentation broth of strain A01 using column chromatography and HPLC. The chemical structural analysis with UV, IR, MS, and NMR confirmed that the compound produced by the strain A01 is natamycin, a polyene antibiotic produced by S. chattanovgensis, S. natalensis, and S. gilvosporeus, widely used as a natural biological preservative for food according to previous reports. The present study revealed a new producing strain of natamycin and its potential application as a biological control agent for fungal plant diseases.A cepa Actinomyces A01 foi isolada do solo de um campo agrícola no subúrbio de Beijing, China. De acordo com as características morfológicas, culturais, fisiológicas e bioquímicas, e análise da sequência 16S rDNA , a cepa A01 foi identificada como Streptomyces lydicus. Nos testes de espectro antimicrobiano, a cepa A01 apresentou atividade inibitória intensa e estável contra vários fungos patogênicos para plantas, como Fusarium oxysporum, Botrytis cinerea, Monilia laxa, etc. Entretanto, não foi encontrada atividade antibacteriana. Em experimentos em estufas, o desenvolvimento do fungo cinza do tomate foi fortemente

  8. Isolation, identification, and characterization of an Aspergillus niger bioflocculant-producing strain using potato starch wastewater as nutrilite and its application.

    Science.gov (United States)

    Pu, Shengyan; Ma, Hui; Deng, Daili; Xue, Shengyang; Zhu, Rongxin; Zhou, Yan; Xiong, Xingying

    2018-01-01

    A bioflocculant (MBFA18) was produced by Aspergillus niger (A18) using potato starch wastewater (PSW) as nutrients. The cultivation processes and flocculating treatment for PSW purification were systematically studied. The flocculating rate of the MBFA 18 achieved 90.06% (kaolin clay) under the optimal cultivation condition (PSW with 5950 mg/L COD, 20 g/L glucose, 0.2 g/L urea and without phosphorus source addition and pH adjustment). Furthermore, effects of flocculant dosage, initial pH, coagulant aid (CaCl2) addition and sedimentation time on the PSW treatment were discussed and studied in detail. The optimum flocculation treatment conditions were determined according to the treatment efficiency, cost and flocculation conditions. During the PSW treatment, 2 mL/L bioflocculant (1.89 g/L) dosage and 0.5 mol/L coagulant aid addition were applied without pH adjustment and 91.15% COD and 60.22% turbidity removal rate could be achieved within 20 min. The comparative study between the bioflocculant and conventional chemical flocculants showed excellent flocculating efficiency of MBFA 18 with lower cost (4.7 yuan/t), which indicated that the bioflocculant MBFA 18 produced in PSW substrate has a great potential to be an alternative flocculant in PSW treatment.

  9. Development of an anhydrotetracycline-inducible gene expression system for solvent-producing Clostridium acetobutylicum: A useful tool for strain engineering.

    Science.gov (United States)

    Dong, Hongjun; Tao, Wenwen; Zhang, Yanping; Li, Yin

    2012-01-01

    Clostridium acetobutylicum is an important solvent (acetone-butanol-ethanol) producing bacterium. However, a stringent, effective, and convenient-to-use inducible gene expression system that can be used for regulating the gene expression strength in C. acetobutylicum is currently not available. Here, we report an anhydrotetracycline-inducible gene expression system for solvent-producing bacterium C. acetobutylicum. This system consists of a functional chloramphenicol acetyltransferase gene promoter containing tet operators (tetO), Pthl promoter (thiolase gene promoter from C. acetobutylicum) controlling TetR repressor expression cassette, and the chemical inducer anhydrotetracycline (aTc). The optimized system, designated as pGusA2-2tetO1, allows gene regulation in an inducer aTc concentration-dependent way, with an inducibility of over two orders of magnitude. The stringency of TetR repression supports the introduction of the genes encoding counterselective marker into C. acetobutylicum, which can be used to increase the mutant screening efficiency. This aTc-inducible gene expression system will thus increase the genetic manipulation capability for engineering C. acetobutylicum. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. EPS-SJ exopolisaccharide produced by the strain Lactobacillus paracasei subsp. paracasei BGSJ2-8 is involved in adhesion to epithelial intestinal cells and decrease on E. coli association to Caco-2 cells

    Directory of Open Access Journals (Sweden)

    Milica eZivkovic

    2016-03-01

    Full Text Available The aim of this study was to determine the role of an exopolysaccharide produced by natural dairy isolate Lactobacillus paracasei subsp. paracasei BGSJ2-8, in the adhesion to intestinal epithelial cells and a decrease in E. coli’s association with Caco-2 cells. Annotation of the BGSJ2-8 genome showed the presence of a gene cluster, epsSJ, which encodes the biosynthesis of the strain-specific exopolysaccharide EPS-SJ, detected as two fractions (P1 and P2 by size exclusion chromatography (SEC coupled with multi-angle laser light scattering (MALLS detection. SEC-MALLS analysis revealed that an EPS-SJ‒ mutant (EPS7, obtained by insertion mutagenesis of the glps_2198 gene encoding primary glycosyltransferase does not produce the P2 fraction of EPS-SJ. Transmission electron microscopy showed that EPS7 mutant has a thinner cell wall compared to the EPS-SJ+ strain BGSJ2-83 (a plasmid free-derivative of BGSJ2-8. Interestingly, strain BGSJ2-83 showed higher adhesion to Caco-2 epithelial intestinal cell line than the EPS7 mutant. Accordingly, BGSJ2-83 effectively reduced E. coli ATCC25922’s association with Caco-2 cells, while EPS7 did not show statistically significant differences. In addition, the effect of EPS-SJ on the proliferation of lymphocytes in gastrointestinal associated lymphoid tissue (GALT was tested and the results showed that the reduction of GALT lymphocyte proliferation was higher by BGSJ2-83 than by the mutant. To the best of our knowledge this is the first report indicating that the presence of EPS (EPS-SJ on the surface of lactobacilli can improve communication between bacteria and intestinal epithelium, implying its possible role in gut colonization.

  11. Jerusalem artichoke powder: a useful material in producing high-optical-purity l-lactate using an efficient sugar-utilizing thermophilic Bacillus coagulans strain.

    Science.gov (United States)

    Wang, Limin; Xue, Zhangwei; Zhao, Bo; Yu, Bo; Xu, Ping; Ma, Yanhe

    2013-02-01

    Jerusalem artichoke is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as lactic acid, is an important objective in industrial biotechnology. In this study, high-optical-purity l-lactate was efficiently produced from the hydrolysates of Jerusalem artichoke powder by a thermophilic bacterium, Bacillus coagulans XZL4. High l-lactate production (134gl(-1)) was obtained using 267gl(-1) Jerusalem artichoke powder (total reducing sugars of 140gl(-1)) and 10gl(-1) of corn steep powder in fed-batch fermentation, with an average productivity of 2.5gl(-1)h(-1) and a yield of 0.96gg(-1) reducing sugars. The final product optical purity is 99%, which meets the requirement of lactic acid polymerization. Our study represents a cost-effective and promising method for polymer-grade l-lactate production using a cheap raw bio-resource. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Decolorization of the azo dye Acid Orange 51 by laccase produced in solid culture of a newly isolated Trametes trogii strain.

    Science.gov (United States)

    Daâssi, Dalel; Zouari-Mechichi, Hela; Frikha, Fakher; Martinez, Maria Jesus; Nasri, Moncef; Mechichi, Tahar

    2013-04-01

    This study concerns the decolorization and detoxification of the azo dye Acid Orange 51 (AO51) by crude laccase from Trametes trogii produced in solid culture using sawdust as support media. A three-level Box-Behnken factorial design with four factors (enzyme concentration, 1-hydroxybenzotriazole (HBT) concentration, dye concentration and reaction time) combined with response surface methodology was applied to optimize AO51 decolorization. A mathematical model was developed showing the effect of each factor and their interactions on color removal. The model predicted that Acid Orange 51 decolorization above 87.87 ± 1.27 % could be obtained when enzyme concentration, HBT concentration, dye concentration and reaction time were set at 1 U/mL, 0.75 mM, 60 mg/L and 2 days, respectively. The experimental values were in good agreement with the predicted ones and the models were highly significant, the correlation coefficient (R 2 ) being 0.9. Then the desirability function was employed to determine the optimal decolorization condition for each dye and minimize the process cost simultaneously. In addition, germination index assay showed that laccase-treated dye was detoxified; however in the presence of HBT, the phytotoxicity of the treated dye was increased. By using cheap agro-industrial wastes, such as sawdust, a potential laccase was obtained. The low cost of laccase production may further broaden its application in textile wastewater treatment.

  13. The hydrocarbon-degrading marine bacterium Cobetia sp. strain MM1IDA2H-1 produces a biosurfactant that interferes with quorum sensing of fish pathogens by signal hijacking

    Science.gov (United States)

    Ibacache-Quiroga, C; Ojeda, J; Espinoza-Vergara, G; Olivero, P; Cuellar, M; Dinamarca, M A

    2013-01-01

    Summary Biosurfactants are produced by hydrocarbon-degrading marine bacteria in response to the presence of water-insoluble hydrocarbons. This is believed to facilitate the uptake of hydrocarbons by bacteria. However, these diffusible amphiphilic surface-active molecules are involved in several other biological functions such as microbial competition and intra-or inter-species communication. We report the isolation and characterization of a marine bacterial strain identified as Cobetia sp. MM1IDA2H-1, which can grow using the sulfur-containing heterocyclic aromatic hydrocarbon dibenzothiophene (DBT). As with DBT, when the isolated strain is grown in the presence of a microbial competitor, it produces a biosurfactant. Because the obtained biosurfactant was formed by hydroxy fatty acids and extracellular lipidic structures were observed during bacterial growth, we investigated whether the biosurfactant at its critical micelle concentration can interfere with bacterial communication systems such as quorum sensing. We focused on Aeromonas salmonicida subsp. salmonicida, a fish pathogen whose virulence relies on quorum sensing signals. Using biosensors for quorum sensing based on Chromobacterium violaceum and Vibrio anguillarum, we showed that when the purified biosurfactant was mixed with N-acyl homoserine lactones produced by A. salmonicida, quorum sensing was inhibited, although bacterial growth was not affected. In addition, the transcriptional activities of A. salmonicida virulence genes that are controlled by quorum sensing were repressed by both the purified biosurfactant and the growth in the presence of Cobetia sp. MM1IDA2H-1. We propose that the biosurfactant, or the lipid structures interact with the N-acyl homoserine lactones, inhibiting their function. This could be used as a strategy to interfere with the quorum sensing systems of bacterial fish pathogens, which represents an attractive alternative to classical antimicrobial therapies in fish

  14. Running Title: Strained Yoghurts

    African Journals Online (AJOL)

    USER

    2012-09-27

    Sep 27, 2012 ... ever, the traditional method of producing strained yoghurt ... Food market studies have the essential function of providing ..... Communication No: 2001/21. ... fermented foods and beverages of Turkey. Crit. Rev. Food. Sci. Nutr.

  15. Phenylacetic acid-producing Rhizoctonia solani represses the biosynthesis of nematicidal compounds in vitro and influences biocontrol of Meloidogyne incognita in tomato by Pseudomonas fluorescens strain CHA0 and its GM derivatives.

    Science.gov (United States)

    Siddiqui, I A; Shaukat, S S

    2005-01-01

    The aim of the present investigation was to determine the influence of Rhizoctonia solani and its pathogenicity factor on the production of nematicidal agent(s) by Pseudomonas fluorescens strain CHA0 and its GM derivatives in vitro and nematode biocontrol potential by bacterial inoculants in tomato. One (Rs7) of the nine R. solani isolates from infected tomato roots inhibited seedling emergence and caused root rot in tomato. Thin layer chromatography revealed that culture filtrates of two isolates (Rs3 and Rs7) produced brown spots at Rf-values closely similar to synthetic phenylacetic acid (PAA), a phytotoxic factor. Filtrates from isolate Rs7, amended with the growth medium of P. fluorescens, markedly repressed nematicidal activity and PhlA'-'LacZ reporter gene expression of the bacteria in vitro. On the contrary, isolate Rs4 enhanced nematicidal potential of a 2,4-diacetylphloroglucinol overproducing mutant, CHA0/pME3424, of P. fluorescens strain CHA0 in vitro. Therefore, R. solani isolates Rs4 and Rs7 were tested more rigorously for their potential to influence biocontrol effectiveness of the bacterial agents. Methanol extract of the culture filtrates of PAA-producing isolate Rs7 resulting from medium amended with phenylalanine enhanced fungal repression of the production of nematicidal agents by bacteria, while amendments with zinc or molybdenum eliminated such fungal repression, thereby restoring bacterial potential to cause nematode mortality in vitro. A pot experiment was carried out, 3-week-old tomato seedlings were infested with R. solani isolates Rs4 or Rs7 and/or inoculated with Meloidogyne incognita, the root-knot nematode. The infested soil was treated with aqueous cell suspensions (10(8) CFU) of P. fluorescens strain CHA0 or its GM derivatives or left untreated (as a control). Observations taken 45 days after nematode inoculation revealed that, irrespective of the bacterial treatments, galling intensity per gram of fresh tomato roots was markedly

  16. Hydrogen production from microbial strains

    Science.gov (United States)

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  17. Antimicrobial multiple resistance index, minimum inhibitory concentrations, and extended-spectrum beta-lactamase producers of Proteus mirabilis and Proteus vulgaris strains isolated from domestic animals with various clinical manifestations of infection

    Directory of Open Access Journals (Sweden)

    Vanessa Zappa

    2017-05-01

    in dogs (n = 25; 75.76%, particularly in those with cystitis (n = 13; 52.0%, followed by bovines (n = 4; 12.12%, equines (n = 2; 6.06%, and cats (n = 2; 6.06%. Two (2.7% strains, obtained from canine skin and feces, were diagnosed phenotypically as ESBL-producers. Here, we observed the diversity of Proteus infections in domestic animals. The presence of multidrug-resistant isolates and ESBL-producers reinforces the need for appropriate antimicrobial use and in vitro antimicrobial tests to support therapy.

  18. Phytochemistry and Preliminary Assessment of the Antibacterial Activity of Chloroform Extract of Amburana cearensis (Allemão) A.C. Sm. against Klebsiella pneumoniae Carbapenemase-Producing Strains

    Science.gov (United States)

    Sá, Mirivaldo Barros; Ralph, Maria Taciana; Nascimento, Danielle Cristina Oliveira; Ramos, Clécio Souza; Barbosa, Isvânia Maria Serafin; Sá, Fabrício Bezerra; Lima-Filho, J. V.

    2014-01-01

    The chloroform extract of the stem bark of Amburana cearensis was chemically characterized and tested for antibacterial activity.The extract was analyzed by gas chromatography and mass spectrometry. The main compounds identified were 4-methoxy-3-methylphenol (76.7%), triciclene (3.9%), α-pinene (1.0%), β-pinene (2.2%), and 4-hydroxybenzoic acid (3.1%). Preliminary antibacterial tests were carried out against species of distinct morphophysiological characteristics: Escherichia coli, Salmonella enterica Serotype Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. The minimum inhibitory concentration (MIC) was determinate in 96-well microplates for the chloroform extract and an analogue of themain compound identified, which was purchased commercially.We have shown that plant's extract was only inhibitory (but not bactericidal) at the maximum concentration of 6900 μg/mL against Pseudomonas aeruginosa and Bacillus cereus. Conversely, the analogue 2-methoxy-4-methylphenol produced MICs ranging from215 to 431 μg/mL against all bacterial species.New antibacterial assays conducted with such chemical compound against Klebsiella pneumoniae carbapenemase-producing strains have shown similarMICresults and minimumbactericidal concentration (MBC) of 431 μg/mL.We conclude that A. cearensis is a good source of methoxy-methylphenol compounds,which could be screened for antibacterial activity againstmultiresistant bacteria fromdifferent species PMID:24772183

  19. Phytochemistry and Preliminary Assessment of the Antibacterial Activity of Chloroform Extract of Amburana cearensis (Allemão A.C. Sm. against Klebsiella pneumoniae Carbapenemase-Producing Strains

    Directory of Open Access Journals (Sweden)

    Mirivaldo Barros Sá

    2014-01-01

    Full Text Available The chloroform extract of the stem bark of Amburana cearensis was chemically characterized and tested for antibacterial activity.The extract was analyzed by gas chromatography and mass spectrometry. The main compounds identified were 4-methoxy-3-methylphenol (76.7%, triciclene (3.9%, α-pinene (1.0%, β-pinene (2.2%, and 4-hydroxybenzoic acid (3.1%. Preliminary antibacterial tests were carried out against species of distinct morphophysiological characteristics: Escherichia coli, Salmonella enterica Serotype Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. The minimum inhibitory concentration (MIC was determinate in 96-well microplates for the chloroform extract and an analogue of themain compound identified, which was purchased commercially.We have shown that plant’s extract was only inhibitory (but not bactericidal at the maximum concentration of 6900 μg/mL against Pseudomonas aeruginosa and Bacillus cereus. Conversely, the analogue 2-methoxy-4-methylphenol produced MICs ranging from215 to 431 μg/mL against all bacterial species.New antibacterial assays conducted with such chemical compound against Klebsiella pneumoniae carbapenemase-producing strains have shown similarMICresults and minimumbactericidal concentration (MBC of 431 μg/mL.We conclude that A. cearensis is a good source of methoxy-methylphenol compounds,which could be screened for antibacterial activity againstmultiresistant bacteria fromdifferent species

  20. Influência da antibiose exercida por actinomicetos às estirpes de Bradyrhizobium SPP., na nodulação da soja Influence of antibiosis produced by actinomycetes on strains of Bradyrhizobium SPP. on soybean nodulation

    Directory of Open Access Journals (Sweden)

    João Carlos Pereira

    1999-01-01

    Full Text Available Este trabalho teve por objetivo avaliar o espectro antibiótico de actinomicetos provenientes de solos de Cerrados e a sua influência na nodulação da soja. As estirpes BR 29, BR 33, BR 40, BR 85, BR 86, BR 96, 47/587, 3B-7 e 4A-5 de Bradyrhizobium spp. apresentaram comportamento diferenciado em relação à resistência natural aos antibióticos produzidos por 204 actinomicetos. As estirpes BR 29 e BR 96 foram sensíveis a 5,2 e 9,9% dos antibióticos produzidos, respectivamente, enquanto a BR 33 apresentou sensibilidade a 20,3%. O antagonismo exercido pelos actinomicetos exclusivamente à BR 29 e BR 33 foi de 1,6 e 5,7%, respectivamente. Esse efeito não foi observado nas estirpes BR 40 e BR 96. Inoculações simples e em mistura das estirpes na presença de actinomicetos influenciaram a nodulação da soja. A co-inoculação da BR 33 e BR 29 com o isolado 370 reduziu o percentual de ocorrência média, nos nódulos, da BR 29, de 94,1% para 83,7%, com conseqüente aumento da BR 33 de 6,7% para 17,2%. Os resultados evidenciam a importância de estudos ecológicos desses microrganismos, visando avaliar o seu papel no estabelecimento de uma nodulação eficiente.The aim of this work was to evaluate the antibiotic spectrum of actinomycetes from Cerrado soils and their influence on soybean nodulation. Strains BR 29, BR 33, BR 40, BR 85, BR 86, BR 96, 47/587, 3B-7 and 4A-5 of Bradyrhizobium spp. were characterized by their natural resistence to antibiotics produced by 204 actinomycete isolates. The strains BR 29 and BR 96 of B. elkanii were sensitive to 5.2% and 9.9% the products of actinomycete isolates, respectively, while BR 33 was sensitive up to 20.3%. The antagonistic effects caused by actinomycete exclusively to BR 29 and BR 33 were 1.6% and 5.7% respectively. This effect was not observed for strains BR 40 and BR 96. Single and multistrains inoculations in the presence or absence of actinomycetes affected soybean nodulation. On double

  1. [Distiller Yeasts Producing Antibacterial Peptides].

    Science.gov (United States)

    Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

    2015-01-01

    A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

  2. Rapid and simple method by combining FTA™ card DNA extraction with two set multiplex PCR for simultaneous detection of non-O157 Shiga toxin-producing Escherichia coli strains and virulence genes in food samples.

    Science.gov (United States)

    Kim, S A; Park, S H; Lee, S I; Ricke, S C

    2017-12-01

    The aim of this research was to optimize two multiplex polymerase chain reaction (PCR) assays that could simultaneously detect six non-O157 Shiga toxin-producing Escherichia coli (STEC) as well as the three virulence genes. We also investigated the potential of combining the FTA™ card-based DNA extraction with the multiplex PCR assays. Two multiplex PCR assays were optimized using six primer pairs for each non-O157 STEC serogroup and three primer pairs for virulence genes respectively. Each STEC strain specific primer pair only amplified 155, 238, 321, 438, 587 and 750 bp product for O26, O45, O103, O111, O121 and O145 respectively. Three virulence genes were successfully multiplexed: 375 bp for eae, 655 bp for stx1 and 477 bp for stx2. When two multiplex PCR assays were validated with ground beef samples, distinctive bands were also successfully produced. Since the two multiplex PCR examined here can be conducted under the same PCR conditions, the six non-O157 STEC and their virulence genes could be concurrently detected with one run on the thermocycler. In addition, all bands clearly appeared to be amplified by FTA card DNA extraction in the multiplex PCR assay from the ground beef sample, suggesting that an FTA card could be a viable sampling approach for rapid and simple DNA extraction to reduce time and labour and therefore may have practical use for the food industry. Two multiplex polymerase chain reaction (PCR) assays were optimized for discrimination of six non-O157 Shiga toxin-producing Escherichia coli (STEC) and identification of their major virulence genes within a single reaction, simultaneously. This study also determined the successful ability of the FTA™ card as an alternative to commercial DNA extraction method for conducting multiplex STEC PCR assays. The FTA™ card combined with multiplex PCR holds promise for the food industry by offering a simple and rapid DNA sample method for reducing time, cost and labour for detection of STEC in

  3. Selection of 80 newly isolated autochthonous yeast strains from the Tikveš region of Macedonia and their impact on the quality of red wines produced from Vranec and Cabernet Sauvignon grape varieties.

    Science.gov (United States)

    Ilieva, Fidanka; Kostadinović Veličkovska, Sanja; Dimovska, Violeta; Mirhosseini, Hamed; Spasov, Hristo

    2017-02-01

    The main objectives of this study were to (i) isolate newly autochthonous yeast strains from the Tikveš region of Macedonia and (ii) test their impact on the quality of red wines from Vranec and Cabernet Sauvignon grape varieties. The newly isolated yeast strains were obtained by spontaneous fermentation of grape must from Vranec and Cabernet Sauvignon varieties collected from ten different micro-regions in Macedonia. The grapevines from both varieties grown in "Barovo" micro-region were the richest sources of yeast strains. In addition, the molecular identification and typing of strains were also carried out. The monomeric anthocyanins, polyphenolic content and other oenochemical characteristics of the wines were also compared with the wines from commercial yeast strain "SiHa". The Vranec wine from yeast strain F-8 and Cabernet Sauvignon wine from yeast strain F-20 had significantly (p<0.05) higher concentrations of monomeric anthocyanins and total phenolic compounds than other wines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Structural analysis of bioengineered alpha-D-glucan produced by a triple mutant of the glucansucrase GTF180 enzyme from Lactobacillus reuteri strain 180 : Generation of (alpha 1 -> 4) linkages in a native (1 -> 3)(1 -> 6)-alpha-D-glucan

    NARCIS (Netherlands)

    van Leeuwen, Sander S.; Kralj, Slavko; Gerwig, Gerrit J.; Dijkhuizen, Lubbert; Kamerling, Johannis P.

    Site-directed mutagenesis of the glucansucrase gtf180 gene from Lactobacillus reuteri strain 180 was used to transform the active site region. The alpha-D-glucan (mEPS-PNNS) produced by the triple mutant V1027P:S1137N: A1139S differed in structure from that of the wild-type alpha-D-glucan (EPS180).

  5. Identification of Two Novel Anti-Fibrotic Benzopyran Compounds Produced by Engineered Strains Derived from Streptomyces xiamenensis M1-94P that Originated from Deep-Sea Sediments

    Directory of Open Access Journals (Sweden)

    Lei Feng

    2013-10-01

    Full Text Available The benzopyran compound obtained by cultivating a mangrove-derived strain, Streptomyces xiamenensis strain 318, shows multiple biological effects, including anti-fibrotic and anti-hypertrophic scar properties. To increase the diversity in the structures of the available benzopyrans, by means of biosynthesis, the strain was screened for spontaneous rifampicin resistance (Rif, and a mutated rpsL gene to confer streptomycin resistance (Str, was introduced into the S. xiamenensis strain M1-94P that originated from deep-sea sediments. Two new benzopyran derivatives, named xiamenmycin C (1 and D (2, were isolated from the crude extracts of a selected Str-Rif double mutant (M6 of M1-94P. The structures of 1 and 2 were identified by analyzing extensive spectroscopic data. Compounds 1 and 2 both inhibit the proliferation of human lung fibroblasts (WI26, and 1 exhibits better anti-fibrotic activity than xiamenmycin. Our study presents the novel bioactive compounds isolated from S. xiamenensis mutant strain M6 constructed by ribosome engineering, which could be a useful approach in the discovery of new anti-fibrotic compounds.

  6. Dose responses of in vivo- and in vitro-produced strains of gypsy moth (Lepidoptera: Lymantriidae) nucleopolyhedrovirus (LdMNPV) applied with and without the virus enhancer Blankophor BBH

    Science.gov (United States)

    John D. Podgwaite; James M. Slavicek; Kevin W. Thorpe; Ralph E. Webb; Roger W. Fuester; Vincent D' Amico; Randel A. Peiffer; Michael A. Valenti

    2013-01-01

    The gypsy moth, Lymantria dispar L., nucleopolyhedrovirus (LdMNPV) product Gypchek is a microbial pesticide produced by the USDA Forest Service. Gypchek is a mixture of LdMNPV genotypes produced in vivo. Commercial interests prefer to develop a stable, high-potency genotype that can be produced at low cost, preferably in vitro. We sprayed 2 LdMNPV...

  7. Isolation and molecular characterization of phytase producing ...

    African Journals Online (AJOL)

    Isolation and molecular characterization of phytase producing bacteria from Malaysia hot springs. ... The strains were further analyzed in broth culture using sodium phytate as substrate. Among them, strain L3 was selected as the best producer (0.16 U/ml after 72 h of culture). This phytase showed optimal activity at 37 °C ...

  8. Strain comparisons in aquaculture species: a manual

    OpenAIRE

    Ponzoni, R.W.; James, J.W.; Nguyen, N.H.; Mekkawy, W.; Khaw, H.L.

    2013-01-01

    When different strains or breeds of a particular species are available, the best choice is seldom immediately obvious for producers. Scientists are also interested in the relative performance of different strains because it provides a basis for recommendations to producers and it often stimulates the conduct of work aimed at unraveling the underlying biological mechanisms involved in the expression of such differences. Hence, strain or breed comparisons of some sort are frequently conducted. ...

  9. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  10. Genomic Analysis of Multidrug-Resistant Escherichia coli from North Carolina Community Hospitals: Ongoing Circulation of CTX-M-Producing ST131-H30Rx and ST131-H30R1 Strains.

    Science.gov (United States)

    Kanamori, Hajime; Parobek, Christian M; Juliano, Jonathan J; Johnson, James R; Johnston, Brian D; Johnson, Timothy J; Weber, David J; Rutala, William A; Anderson, Deverick J

    2017-08-01

    Escherichia coli sequence type 131 (ST131) predominates globally among multidrug-resistant (MDR) E. coli strains. We used whole-genome sequencing (WGS) to investigate 63 MDR E. coli isolates from 7 North Carolina community hospitals (2010 to 2015). Of these, 39 (62%) represented ST131, including 37 (95%) from the ST131- H 30R subclone: 10 (27%) from its H 30R1 subset and 27 (69%) from its H 30Rx subset. ST131 core genomes differed by a median of 15 (range, 0 to 490) single-nucleotide variants (SNVs) overall versus only 7 within H 30R1 (range, 3 to 12 SNVs) and 11 within H 30Rx (range, 0 to 21). The four isolates with identical core genomes were all H 30Rx. Epidemiological and clinical characteristics did not vary significantly by strain type, but many patients with MDR E. coli or H 30Rx infection were critically ill and had poor outcomes. H 30Rx isolates characteristically exhibited fluoroquinolone resistance and CTX-M-15 production, had a high prevalence of trimethoprim-sulfamethoxazole resistance (89%), sul1 (89%), and dfrA17 (85%), and were enriched for specific virulence traits, and all qualified as extraintestinal pathogenic E. coli The high overall prevalence of CTX-M-15 appeared to be possibly attributable to its association with the ST131- H 30Rx subclone and IncF[F2:A1:B-] plasmids. Some phylogenetically clustered non-ST131 MDR E. coli isolates also had distinctive serotypes/ fimH types, fluoroquinolone mutations, CTX-M variants, and IncF types. Thus, WGS analysis of our community hospital source MDR E. coli isolates suggested ongoing circulation and differentiation of E. coli ST131 subclones, with clonal segregation of CTX-M variants, other resistance genes, Inc-type plasmids, and virulence genes. Copyright © 2017 American Society for Microbiology.

  11. Analysis of the secondary compounds produced by Saccharomyces cerevisiae and wild yeast strains during the production of "cachaça" Análise dos componentes secundários produzidos por Saccharomyces cerevisiae e leveduras selvagens durante a produção de cachaça

    Directory of Open Access Journals (Sweden)

    Maria Cecília Fachine Dato

    2005-03-01

    Full Text Available The aim of this study is to compare the composition of "cachaças" produced in 10 fermentation cycles by Saccharomyces cerevisiae (Sc and wild yeast strains [Pichia silvicola (Ps, Pichia anomala 1 (Pa1, Pichia anomala 2 (Pa2 and Dekkera bruxelensis (Db], isolated from distilleries in Jaboticabal - SP, Brazil. The secondary components of the heart fraction were determined by gas chromatography. The levels of secondary components were influenced by the wine pH, which varied among yeast strains. S. cerevisiae showed slightly more secondary components, whereas wild strains produced more higher alcohols. Wild yeast strains were shown to be adequate for the production of a high quality "cachaça".O presente trabalho visou estabelecer uma comparação entre composição de cachaças produzidas por Saccharomyces cerevisiae (Sc e estirpes de leveduras selvagens [Pichia silvicola (Ps, Pichia anomala 1 (Pa1, Pichia anomala 2 (Pa2 e Dekkera bruxelensis (Db], isoladas em destilarias da região de Jaboticabal-SP. Os componentes secundários da fração denominada coração foram determinados por cromatografia gasosa. Os níveis dos componentes secundários foram influenciados pelo pH dos respectivos vinhos, os quais dependem da estirpe de levedura empregada no processo fermentativo. A Saccharomyces cerevisiae apresentou valores ligeiramente superiores de componentes secundários, enquanto as estirpes selvagens produziram maiores teores de álcoois superiores. As estirpes selvagens de leveduras mostraram-se adequadas para obtenção de uma cachaça de boa qualidade.

  12. Comments on "Screening and identification of novel ochratoxin A-producing fungi from grapes. Toxins 2016,8,833" - in reporting ochratoxin A production from strains of Aspergillus, Penicillium and talaromcyes

    DEFF Research Database (Denmark)

    Perrone, Giancarlo; Logrieco, Antonio F.; Frisvad, Jens Christian

    2017-01-01

    Recently a species in the genus Talaromyces, a uniseriate species of Aspergillus section Nigri and an isolate each of two widespread species, Penicillium rubens and P. commune, were reported to produce ochratoxin A. This claim was based on insufficient biological and chemical data. We propose a l...

  13. Selection of Potential Therapeutic Bacteriophages that Lyse a CTX-M-15 Extended Spectrum β-Lactamase Producing Salmonella enterica Serovar Typhi Strain from the Democratic Republic of the Congo

    Directory of Open Access Journals (Sweden)

    Elene Kakabadze

    2018-04-01

    Full Text Available Recently, a Salmonella Typhi isolate producing CTX-M-15 extended spectrum β-lactamase (ESBL and with decreased ciprofloxacin susceptibility was isolated in the Democratic Republic of the Congo. We have selected bacteriophages that show strong lytic activity against this isolate and have potential for phage-based treatment of S. Typhi, and Salmonella in general.

  14. Mutations in the Histone-like Nucleoid Structuring Regulatory Gene (hns) Decrease the Adherence of Shiga Toxin-producing Escherichia coli 091:H21 Strain B2F1 to Human Colonic Epithelial Cells and Increase the Production of Hemolysin

    Science.gov (United States)

    1999-10-19

    osmoregulation of outer membrane proteins and virulence determinants in Vibrio cholerae requires toxR. J. Bacteriol. 170:2575-2583. Mobley, H. L., D. M. Green...produced by ETEC organisms is homologous to the toxin encoded by Y: cholerae . These toxins are the primary cause of the watery diarrhea associated with ETEC...Escherichia coli as a cause ofdiarrhea among children in Mexico . J. Clin. Microbiol. 25:1913-1919. Maurelli, A. T., and P. J. Sansonetti. 1988

  15. Target-oriented discovery of a new esterase-producing strain Enterobacter sp. ECU1107 for whole cell-catalyzed production of (2S,3R)-3-phenylglycidate as a chiral synthon of Taxol.

    Science.gov (United States)

    Zhou, Dong-Jie; Pan, Jiang; Yu, Hui-Lei; Zheng, Gao-Wei; Xu, Jian-He

    2013-07-01

    A new strain, Enterobacter sp. ECU1107, was identified among over 200 soil isolates using a two-step screening strategy for the enantioselective synthesis of (2S,3R)-3-phenylglycidate methyl ester (PGM), a key intermediate for production of a potent anticancer drug Taxol®. An organic-aqueous biphasic system was employed to reduce spontaneous hydrolysis of the substrate PGM and isooctane was found to be the most suitable organic solvent. The temperature and pH optima of the whole cell-mediated bioreaction were 40 °C and 6.0, respectively. Under these reaction conditions, the enantiomeric excess (ee(s)) of (2S,3R)-PGM recovered was greater than 99 % at approximately 50 % conversion. The total substrate loading in batch reaction could reach 600 mM. By using whole cells of Enterobacter sp. ECU1107, (2S,3R)-PGM was successfully prepared in decagram scale in a 1.0-l mechanically stirred reactor, affording the chiral epoxy ester in >99 % ee s and 43.5 % molar yield based on the initial load of racemic substrate.

  16. Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

    DEFF Research Database (Denmark)

    Frisvad, Jens Christian; Larsen, Thomas Ostenfeld; Thrane, Ulf

    2011-01-01

    as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were...... examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B(2), B(4), and B(6)) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83......%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also...

  17. Microstructure and Textural Properties of Yoghurts Produced by Exopolysaccharides- Producing Starter Cultures

    DEFF Research Database (Denmark)

    Zhang, Lanjun

    conferred a ropy texture and resulted in yoghurts with decreased water holding capacity and an open microstructure. In addition, one of the LB strains with high amounts of EPS producing capacity improved water retention, when it was combined with an ST strain that produced negligible amounts of EPS...

  18. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures

    DEFF Research Database (Denmark)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul

    2016-01-01

    V. harveyi, which is the major bacterial pathogen in crustaceans and Mediterranean sea bass larvae cultures. Concomitantly, they significantly improved survival of V. harveyi-infected brine shrimp. 16S rRNA gene sequence homology identified the antagonists as Phaeobacter sp., and in silico DNA...... Vibrio anguillarum and reduce mortality in V. anguillarum-infected cod and turbot larvae. In this study, it was demonstrated that antagonistic Roseobacter-clade bacteria could be isolated from sea bass larval rearing units. In addition, it was shown that they not only antagonized V. anguillarum but also......-producing Phaeobacter isolated from Mediterranean marine larviculture are promising probiotic bacteria against pathogenic Vibrio in crustacean live-feed cultures for marine fish larvae....

  19. Producing cement

    Energy Technology Data Exchange (ETDEWEB)

    Stone, E G

    1923-09-12

    A process and apparatus are described for producing Portland cement in which pulverized shale is successively heated in a series of inclined rotary retorts having internal stirrers and oil gas outlets, which are connected to condensers. The partially treated shale is removed from the lowermost retort by a conveyor, then fed separately or conjointly into pipes and thence into a number of vertically disposed retorts. Each of these retorts may be fitted interiorly with vertical arranged conveyors which elevate the shale and discharge it over a lip, from whence it falls to the bottom of the retorts. The lower end of each casing is furnished with an adjustable discharge door through which the spent shale is fed to a hopper, thence into separate trucks. The oil gases generated in the retorts are exhausted through pipes to condensers. The spent shale is conveyed to a bin and mixed while hot with ground limestone. The admixed materials are then ground and fed to a rotary kiln which is fired by the incondensible gases derived from the oil gases obtained in the previous retorting of the shale. The calcined materials are then delivered from the rotary kiln to rotary coolers. The waste gases from the kiln are utilized for heating the retorts in which the ground shale is heated for the purpose of extracting therefrom the contained hydrocarbon oils and gases.

  20. Development of tolerance against toxic Microcystis aeruginosa in three cladocerans and the ecological implications

    International Nuclear Information System (INIS)

    Guo Nichun; Xie Ping

    2006-01-01

    This is the first experimental study to compare difference in the development of tolerance against toxic Microcystis among multi-species of cladocerans (Daphnia, Moina and Ceriodaphnia) pre-exposed to two M. aeruginosa PCC7820 strains (MC-containing and MC-free). Zooplankton were divided into S population (fed Scenedesmus), M-F population (fed Scenedesmus + MC-free Microcystis), and M-C population (fed Scenedesmus + MC-containing Microcystis). M-F and M-C populations were pre-exposed to Microcystis strains for 4 weeks, and their newborns were collected for experiments. A pre-exposure to MC-containing or MC-free Microcystis increased tolerance against toxic Microcystis. The marked increases in survival rate and median lethal time (LT 5 , 100-194% increase) in the M-C population of Ceriodaphnia suggest that small-sized cladocerans may develop stronger tolerance against Microcystis than large-sized ones when both groups are exposed to toxic Microcystis. This may explain why dominant Daphnia is usually replaced by small-sized cladocerans when cyanobacteria bloomed in summer in eutrophic lakes. - Three cladocerans pre-exposed to Microcystis developed different tolerance against toxic Microcystis, explaining zooplankton succession with blooms

  1. Development of tolerance against toxic Microcystis aeruginosa in three cladocerans and the ecological implications

    Energy Technology Data Exchange (ETDEWEB)

    Guo Nichun [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072 (China); Xie Ping [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072 (China)]. E-mail: xieping@ihb.ac.cn

    2006-10-15

    This is the first experimental study to compare difference in the development of tolerance against toxic Microcystis among multi-species of cladocerans (Daphnia, Moina and Ceriodaphnia) pre-exposed to two M. aeruginosa PCC7820 strains (MC-containing and MC-free). Zooplankton were divided into S population (fed Scenedesmus), M-F population (fed Scenedesmus + MC-free Microcystis), and M-C population (fed Scenedesmus + MC-containing Microcystis). M-F and M-C populations were pre-exposed to Microcystis strains for 4 weeks, and their newborns were collected for experiments. A pre-exposure to MC-containing or MC-free Microcystis increased tolerance against toxic Microcystis. The marked increases in survival rate and median lethal time (LT{sub 5}, 100-194% increase) in the M-C population of Ceriodaphnia suggest that small-sized cladocerans may develop stronger tolerance against Microcystis than large-sized ones when both groups are exposed to toxic Microcystis. This may explain why dominant Daphnia is usually replaced by small-sized cladocerans when cyanobacteria bloomed in summer in eutrophic lakes. - Three cladocerans pre-exposed to Microcystis developed different tolerance against toxic Microcystis, explaining zooplankton succession with blooms.

  2. Development of high temperature strain gage, (5)

    International Nuclear Information System (INIS)

    Yuuki, Hiroshi; Kobayashi, Yukio; Kanai, Kenji; Yamaura, Yoshio

    1976-01-01

    Development and improvement of resistance wire type strain gages usable for experimental measurement of thermal strains generated at high temperature in various structures and equipments that consist of a Fast Breeder Reactor have been carried out, and various characteristics of the strain gages have been investigated. Based on the results obtained up to now, development and research of this time mainly aim to improve strain and fatigue characteristics. As the results, characteristics of strain gages with sensing elements of nichrome V are improved, specifically mechanical hysteresis is decreased, strain limit is increased, etc. Also, improvement is recognized in thermal output, and it becomes clear that dummy gages work effectively. However, a filling method of MgO and an inserting method of active-dummy elements are selected as primary objects to improve strain characteristics, and many hours are taken for these objects, so confirmations of characteristics of platinum-tungsten strain gages, strain sensing elements of which are troublesome to produce, have not been completely done, though the performance of the gages has been improved in several points. As to nichrome V strain gages, there is a fair prospect of obtaining ones, specifications of which are quite close to the goal, though problems in manufacturing technics remain for future. As to platinum-tungsten strain gages, it is expected that similar strain gages to nichrome V are obtainable by improvement in manufacturing of sensing elements. (auth.)

  3. Kinetics of cell lysis for Microcystis aeruginosa and Nitzschia palea in the exposure to β-cyclocitral

    International Nuclear Information System (INIS)

    Chang, De-Wei; Hsieh, Meng-Ling; Chen, Yan-Min; Lin, Tsair-Fuh; Chang, Jo-Shu

    2011-01-01

    The effect of an algal metabolite, β-cyclocitral, on the cell integrity of two cyanobacteria and one diatom was investigated. The cyanobacteria, Microcystis aeruginosa PCC 7005 and PCC 7820, and the diatom, Nitzschia palea, were exposed to various concentrations of β-cyclocitral. Scanning electron microscope (SEM) results indicate that the cells of tested species were greatly altered after being exposed to β-cyclocitral. A flow cytometer coupled with the SYTOX stain and chlorophyll-a auto-fluorescence was used to quantify the effect of β-cyclocitral on cell integrity for the tested cyanobacteria and diatom. Kinetic experiments show that about 5-10 mg L -1 of β-cyclocitral for the two M. aeruginosa strains and a much lower concentration, 0.1-0.5 mg L -1 , for N. palea were needed to cause 15-20% of cells to rupture. When the β-cyclocitral concentration was increased to 200-1000 mg L -1 for M. aeruginosa and 5-10 mg L -1 for N. palea, almost all the cells ruptured between 8 and 24 h. A first-order kinetic model is able to describe the data of cell integrity over time. The extracted rate constant values well correlate with the applied β-cyclocitral dosages. The obtained kinetic parameters may be used to estimate β-cyclocitral dosage and contact time required for the control of cyanobacteria and diatoms in water bodies.

  4. Presença de Staphylococcus spp. produtores de enterotoxinas e da toxina da síndrome do choque tóxico em manipuladores de queijo de cabra Presence of Staphylococcus strains producer of enterotoxins and toxic shock toxin syndrome isolated from goat's cheese handlers

    Directory of Open Access Journals (Sweden)

    L.S. Rapini

    2005-12-01

    Full Text Available Agruparam-se 167 cepas de Staphylococcus, isoladas de diferentes sítios (fossas nasais, orofaringe, palma das mãos e leitos subungueais, de dois manipuladores de queijos de leite de cabra, em pools (45, de acordo com a similaridade da espécie e o local de origem, e testou-se o seu potencial de produção de enterotoxinas (SE A, B, C e D, e da toxina da síndrome do choque tóxico (TSST-1. Constatou-se que 62,2% dos pools foram capazes de produzir, de forma individual ou associada, SEA (33,3%; SEB (46,7%; SEC (8,9%; SED (4,4% e TSST-1 (4,4%. Dos pools enterotoxigênicos, 96,4% corresponderam a espécies coagulase negativa (Staphylococcus epidermidis e Staphylococcus cohnii. A capacidade de produção de SE e de TSST-1 pelas cepas de Staphylococcus spp. isoladas dos manipuladores, além de reafirmar sua importância na transmissão de intoxicações de origem alimentar, enfatiza a necessidade imprescindível da adoção de condutas higiênicas e sanitárias durante a manipulação do alimento.A total of 167 strains of Staphylococcus isolated from nasal cavities, oropharynx, palm of hands and subunguial of two goat's cheese handlers were collected. The strains were pooled (45 according to the species similarity and place of origin and tested for the production of enterotoxins (SE A, B, C, D and toxic shock toxin syndrome (TSST-1. It was observed that 62.2% of the pools presented the capacity to produce, individually or in association, SEA (33.3%; SEB (46.7%; SEC (8.9%; SED (4.4% and TSST-1 (4.4%. From the enterotoxigenic pools, 96.4% corresponded to species negative coagulase (Staphylococcus epidermidis and Staphylococcus cohnii. The capacity to produce SE and TSST-1 by Staphylococcus spp. strains isolated from food handlers reaffirms its hole on the transmission of food poisoning, beyond emphasizing the indispensable necessity of the adoption of satisfactory hygienic and sanitary procedures during the food manufacture.

  5. Mycelial glucoamylases produced by the thermophilic fungus Scytalidium thermophilum strains 15.1 and 15.8: purification and biochemical characterization Glucoamilases miceliais produzidas pelas linhagens 15.1 e 15.8 do fungo termofílico Scytalidium thermophilum: purificação e caracterização bioquímica

    Directory of Open Access Journals (Sweden)

    M.S. Ferreira-Nozawa

    2008-06-01

    Full Text Available Two strains (15.1 and 15.8 of the thermophilic fungus Scytalidium thermophilum produced high levels of intracellular glucoamylases, with potential for industrial applications. The isoform I of the glucoamylase produced by 15.1 strain was sequentially submitted to DEAE-Cellulose and CM-Cellulose chromatography, and purified 141-fold, with 5.45% recovery. The glucoamylase of strain 15.8 was purified 71-fold by CM-Cellulose and Concanavalin A-Sepharose chromatography, with 7.38% recovery. Temperature and pH optima were in the range of 50-60ºC and 5.0-6.0, respectively, using starch and maltose as substrates. The glucoamylase of S. thermophilum 15.8 was more stable (t50 > 60 min than that of S. thermophilum 15.1 (t50= 11-15 min, at 60ºC. The glucoamylase activities were enhanced by several ions (e.g. Mn2+ and Ca2+ and inhibited by β-mercaptoethanol. The glucoamylase from 15.1 strain showed a Km of 0.094 mg/ml and 0.029 mg/ml and Vmax of 202 U/mg prot and 109 U/mg prot, for starch and maltose, respectively. The hydrolysis products of starch and maltose, analyzed by TLC, demonstrated glucose as end product and confirming the character of the enzyme as glucoamylase. Differences were observed in relation to the products formed with maltose as substrate between the two strains studied. S. thermophilum 15.8 formed maltotriose in contrast with S. thermophilum 15.1.Duas linhagens (15.1 e 15.8 do fungo termofílico Scytalidium thermophilum se mostraram produtoras de grandes quantidades de glucoamilases, com potencial aplicação industrial. A isoforma I de glucoamilase produzida pela linhagem 15.1 foi submetida seqüencialmente a cromatografia em colunas de DEAE-celulose e CM-celulose, sendo purificada 141 vezes com porcentagem de recuperação de 5,45%. A glucoamilase da linhagem 15.8 foi purificada 71 vezes através do uso de colunas de cromatografia de CM-celulose e Concanavalina A-sepharose com porcentagem de recuperação de 7,38%. Temperatura e pH

  6. The many shades of prion strain adaptation.

    Science.gov (United States)

    Baskakov, Ilia V

    2014-01-01

    In several recent studies transmissible prion disease was induced in animals by inoculation with recombinant prion protein amyloid fibrils produced in vitro. Serial transmission of amyloid fibrils gave rise to a new class of prion strains of synthetic origin. Gradual transformation of disease phenotypes and PrP(Sc) properties was observed during serial transmission of synthetic prions, a process that resembled the phenomenon of prion strain adaptation. The current article discusses the remarkable parallels between phenomena of prion strain adaptation that accompanies cross-species transmission and the evolution of synthetic prions occurring within the same host. Two alternative mechanisms underlying prion strain adaptation and synthetic strain evolution are discussed. The current article highlights the complexity of the prion transmission barrier and strain adaptation and proposes that the phenomenon of prion adaptation is more common than previously thought.

  7. Effect of ropy and capsular exopolysaccharides producing strain of ...

    African Journals Online (AJOL)

    Administrator

    2004-07-14

    Jul 14, 2004 ... This study was carried out to determine the contribution ... Evolution of pH during the manufacturing process of fermented milk using different combinations of ... Tests were conducted at ambient temperature (approximately.

  8. Cytotoxicity assays for mycotoxins produced by Fusarium strains: a review

    NARCIS (Netherlands)

    Gutleb, A.C.; Morrison, E.; Murk, A.J.

    2002-01-01

    Mycotoxins are naturally occurring toxic secondary metabolites of fungi that may be present in food and feed. Several of these mycotoxins have been associated with human and animal diseases. Fusarium species, found worldwide in cereals and other food types for human and animal consumption, are the

  9. Isolation and characterization of lipase-producing Bacillus strains ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... many industrial processes leading to the development of ... streaked on tributyrin (Hi media 071) agar plates and the formation .... 3d. At pH 7.0. 3e. At pH 8.0. 3f. At pH 9.0. Figure 3. Effect of olive oil on lipase activity of Bacillus ...

  10. Characterization of Thermostable Cellulases Produced by Bacillus and Geobacillus Strains

    Science.gov (United States)

    Bacterial community composition of thermophilic (60 deg C) mixed cellulose-enrichment cultures was examined by constructing a 16S rDNA clone library which demonstrated major lineages affiliated to Actinobacteria, Bacteroidetes, Chloroflexi, Deinococcus-Thermus, Firmicutes, and Proteobacteria. A tot...

  11. 无核白甜葡萄酒产香酵母菌种筛选及其发酵性能研究%Screening of A Yeast Strain with Aroma-producing Capability for Seedless White Grape Wine & Study of Its Fermenting Performance

    Institute of Scientific and Technical Information of China (English)

    雷静; 吴斌; 郭峰; 韩琛; 陈雅; 阿依加马丽

    2016-01-01

    Wine aroma is an important sensory index in the evaluation of wine quality. Aromatic substances are also the important components of both grape and grape wine. Seedless white grape belongs to white grape and its intrinsic aroma is weak. Accordingly, the use of yeast strains with good aroma-producing capabilities in wine-making by seedless white grape is a reliable and safe approach. In the experiments, a yeast strain with good aroma-producing capabilities named W4 was isolated from naturally fermented liquid of seedless white grape. Meanwhile, the fermenting performance of W4 was investigated and the optimum technical parameters were summed up as follows:pH value=3, fermenting temperature at 20℃, and the initial sugar content was 230 g/L. The total esters content in the produced wine by W4 reached up to 7.335 g/L. The screened W4 could increase total esters content in grape wine effectively and evidently.%葡萄酒的香气是评判葡萄酒品质一个重要的感官指标,芳香物质也是构成葡萄和葡萄酒的重要成分。无核白葡萄属于白皮葡萄,自身带有的果香味淡薄。这就需要在酿造工艺上加以改进,采用产香酿酒酵母是可靠安全的增香手段。本研究通过对无核白葡萄自然发酵液分离初筛,筛选出1株产香较好的酵母菌株,命名为W4。同时对筛选出的W4产香酵母菌种进行发酵性能参数确定。通过实验分析得出:W4菌株最适pH值为3、最适发酵温度为20℃、最适初始糖度为230 g/L,发酵所得葡萄酒产酯总量为7.335 g/L。筛选出的菌株可以有效、明显地提高葡萄酒的总酯含量。

  12. Screening of potential biosurfactant-producing bacteria isolated from ...

    African Journals Online (AJOL)

    Seawater represents a specific environment harboring complex bacterial community which is adapted to harsh conditions. Hence, biosurfactant produced by these bacteria under these conditions have interesting proprieties. The screening of biosurfactant producing strains isolated from seawater biofilm was investigated.

  13. Strain-Modulated Epitaxy

    National Research Council Canada - National Science Library

    Brown, April

    1999-01-01

    Strain-Modulated Epitaxy (SME) is a novel approach, invented at Georgia Tech, to utilize subsurface stressors to control strain and therefore material properties and growth kinetics in the material above the stressors...

  14. Hamstring strain - aftercare

    Science.gov (United States)

    Pulled hamstring muscle; Sprain - hamstring ... There are 3 levels of hamstring strains: Grade 1 -- mild muscle strain or pull Grade 2 -- partial muscle tear Grade 3 -- complete muscle tear Recovery time depends ...

  15. Bacteriocin producers from traditional food products

    Directory of Open Access Journals (Sweden)

    Thonart P.

    2007-01-01

    Full Text Available A total of 220 strains of LAB isolated from 32 samples of traditional fermented food from Senegal were screened for bacteriocin production. Two bacteriocin producers, Lactococcus lactis subsp. lactis and Enterococcus faecium, were identified from 12 bacteriocin-producing isolates on the basis of phenotypic analyses and 16S rDNA sequence. Both bacteriocins produced by new isolates show antimicrobial activity against Listeria monocytogenes and Bacillus coagulans whereas only that produced by Lactococcus lactis has an activity against Bacillus cereus. Bacteriocin-producing Lactococcus lactis strains were found in a variety of traditional foods indicating a high potential of growth of this strain in variable ecological complex environment. Partial 16S rDNA of the two bacteriocin producers obtained in this study has been registered to Genbank databases under the accession number AY971748 for Lactococcus lactis subsp. lactis (named CWBI-B1410 and AY971749 for Enterococcus faecium (named CWBI-B1411. The new bacteriocin-producing Lactococcus lactis subsp. lactis strain has been selected for identification and application of the bacteriocin to food preservation.

  16. Biosurfactant-producing yeasts widely inhabit various vegetables and fruits.

    Science.gov (United States)

    Konishi, Masaaki; Maruoka, Naruyuki; Furuta, Yoshifumi; Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2014-01-01

    The isolation of biosurfactant-producing yeasts from food materials was accomplished. By a combination of a new drop collapse method and thin-layer chromatography, 48 strains were selected as glycolipid biosurfactant producers from 347 strains, which were randomly isolated from various vegetables and fruits. Of the producers, 69% were obtained from vegetables of the Brassica family. Of the 48 producers, 15 strains gave relatively high yields of mannosylerythritol lipids (MELs), and were identified as Pseudozyma yeasts. These strains produced MELs from olive oil at yields ranging from 8.5 to 24.3 g/L. The best yield coefficient reached 0.49 g/g as to the carbon sources added. Accordingly, MEL producers were isolated at high efficiency from various vegetables and fruits, indicating that biosurfactant producers are widely present in foods. The present results should facilitate their application in the food and related industries.

  17. Effect of biosurfactant from two strains of Pseudomonas on ...

    African Journals Online (AJOL)

    Two Pseudomonas strains isolated from oil-contaminated soil which produce biosurfactant were studied. The biosurfactant containing broth formed stable emulsions with liquid light paraffin, cooking medium vegetable oil and toluene. The strains under study produce extra cellular biosurfactant in the culture media.

  18. Triacetic acid lactone production in industrial Saccharomyces yeast strains

    Science.gov (United States)

    Triacetic acid lactone (TAL) is a potential platform chemical that can be produced in yeast. To evaluate the potential for industrial yeast strains to produce TAL, the g2ps1 gene encoding 2-pyrone synthase was transformed into thirteen industrial yeast strains of varied genetic background. TAL produ...

  19. Genetic recombination in auxotrophic strains of Phanerochaete chrysosporium

    International Nuclear Information System (INIS)

    Krejci, R.

    1987-01-01

    Four auxotrophic strains of ligninolytic basidiomycete Phanerochaete chrysosporium were obtained by UV mutagenesis. The heterokaryotic mycelium formed by complementation of different auxotrophic isolates was able to fruit and produce basidiospores. Prototrophic strains and strains with a recombined set of parental nutritional requirements were isolated from the basidiospore progeny of the heterokaryons. Genetic recombination hence takes place in fruit bodies produced by the heterokaryotic mycelium. (author). 3 tabs., 13 refs

  20. Caracterização preliminar de bacteriocinas produzidas por seis cepas de bactérias láticas isoladas de produtos cárneos embalados a vácuo Preliminary characterization of bacteriocins produced by six lactic acid bacteria strains isolated from vacuum-packaged meat products

    Directory of Open Access Journals (Sweden)

    Elaine C. P. de Martinis

    2003-08-01

    Full Text Available No presente trabalho, foram estudadas as bacteriocinas produzidas por seis linhagens bacterianas: duas culturas Lactobacillus sake, duas de Lactobacillus curvatus, uma de Leuconostoc mesenteroides, uma de Leuconostoc sp 12. As atividades inibitórias foram quantificadas pelo método da diluição crítica, utilizando-se os indicadores Lactobacillus sake ATCC 15521 e Listeria monocytogenes. As bacteriocinas produzidas foram caracterizadas também quanto à sensibilidade a enzimas, faixa de temperatura na produção, termoestabilidade, estabilidade em diferentes pHs e modo de ação (bactericida ou bacteriostático frente a Listeria monocytogenes. Nenhuma bacteriocina foi destruída pela pepsina, mas todas foram sensíveis à proteinase K, tripsina e alfa-amilase (exceto a bacteriocina produzida por Leuconostoc sp 12, que foi insensível a alfa-amilase. Lactobacillus sake 1, Leuconostoc mesenteroides 11 e Lactobacillus sake 16 apresentaram atividade antilisterial, sendo a maior inibição observada para Lactobacillus sake 1 e Leuconostoc mesenteroides 11 (12.800UA/mL. Lactobacillus sake 1 e Lactobacillus curvatus 5 produziram as bacteriocinas mais termoestáveis. Lactobacillus sake 1 produziu a bacteriocina com maior estabilidade a variações de pH. Todas as bactérias láticas produziram bacteriocina entre 4ºC e 30ºC, sendo esta propriedade muito interessante para futuras aplicações em produtos cárneos refrigerados.In this work, the bacteriocins produced by six bacterial strains were studied (Lactobacillus sake 1, Lactobacillus curvatus 5, Leuconostoc mesenteroides 11, Leuconostoc sp 12, Lactobacillus curvatus 14 and Lactobacillus sake 16. Title of inhibitory activity was determined by critical dilution assay, using Lactobacillus sake ATCC 15521 and Listeria monocytogenes as indicator microorganisms. The inhibitory compounds were also characterized with respect to stability to the action of enzymes, thermostability, stability in several p

  1. A strain gauge

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....

  2. A NEW STRAIN OF TRANSMISSIBLE LEUCEMIA IN FOWLS (STRAIN H).

    Science.gov (United States)

    Ellermann, V

    1921-03-31

    1. A new strain of fowl leucosis has been transmitted through twelve generations of fowls. 2. An increase in virulence was observed during its passage. This was shown in a shortening of the interval between inoculation and death. The increase in virulence does not affect the number of successful inoculations, which remains approximately constant in from 20 to 40 per cent of the birds employed. 3. As with former strains, the disease manifests itself in various forms; i.e., myeloid and intravascular lymphoid types. A single lymphatic case was observed. 4. In several intravascular cases a diminution in the hemolytic power of the serum was established. This phenomenon was absent in a number of myeloid cases. 5. Active immunization cannot be produced by means of the subcutaneous injection of virulent material. 6. The finding of previous experiments that the virus is filterable has been confirmed. 7. The inoculation of human leucemic material into fowls gave negative results.

  3. Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

    Science.gov (United States)

    Frisvad, Jens C.; Larsen, Thomas O.; Thrane, Ulf; Meijer, Martin; Varga, Janos; Samson, Robert A.; Nielsen, Kristian F.

    2011-01-01

    Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B2, B4, and B6) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also produced fumonisins. Strains optimized through random mutagenesis usually maintained their mycotoxin production capability. Toxigenic strains were also able to produce the toxins on media suggested for citric acid production with most of the toxins found in the biomass, thereby questioning the use of the remaining biomass as animal feed. In conclusion it is recommended to use strains of A. niger with inactive or inactivated gene clusters for fumonisins and ochratoxins, or to choose isolates for biotechnological uses in related non-toxigenic species such as A. tubingensis, A. brasiliensis, A vadensis or A. acidus, which neither produce fumonisins nor ochratoxins. PMID:21853139

  4. Development of intra-strain self-cloning procedure for breeding baker's yeast strains.

    Science.gov (United States)

    Nakagawa, Youji; Ogihara, Hiroyuki; Mochizuki, Chisato; Yamamura, Hideki; Iimura, Yuzuru; Hayakawa, Masayuki

    2017-03-01

    Previously reported self-cloning procedures for breeding of industrial yeast strains require DNA from other strains, plasmid DNA, or mutagenesis. Therefore, we aimed to construct a self-cloning baker's yeast strain that exhibits freeze tolerance via an improved self-cloning procedure. We first disrupted the URA3 gene of a prototrophic baker's yeast strain without the use of any marker gene, resulting in a Δura3 homozygous disruptant. Then, the URA3 gene of the parental baker's yeast strain was used as a selection marker to introduce the constitutive TDH3 promoter upstream of the PDE2 gene encoding high-affinity cyclic AMP phosphodiesterase. This self-cloning procedure was performed without using DNA from other Saccharomyces cerevisiae strains, plasmid DNA, or mutagenesis and was therefore designated an intra-strain self-cloning procedure. Using this self-cloning procedure, we succeeded in producing self-cloning baker's yeast strains that harbor the TDH3p-PDE2 gene heterozygously and homozygously, designated TDH3p-PDE2 hetero and TDH3p-PDE2 homo strains, respectively. These self-cloning strains expressed much higher levels of PDE2 mRNA than the parental strain and exhibited higher viability after freeze stress, as well as higher fermentation ability in frozen dough, when compared with the parental strain. The TDH3p-PDE2 homo strain was genetically more stable than the TDH3p-PDE2 hetero strain. These results indicate that both heterozygous and homozygous strains of self-cloning PDE2-overexpressing freeze-tolerant strains of industrial baker's yeast can be prepared using the intra-strain self-cloning procedure, and, from a practical viewpoint, the TDH3p-PDE2 homo strain constructed in this study is preferable to the TDH3p-PDE2 hetero strain for frozen dough baking. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  6. Bacteriocin-producing Enterococci from Rabbit Meat

    Directory of Open Access Journals (Sweden)

    Szabóová, R.

    2012-01-01

    Full Text Available Aims: Enterococci are lactic acid bacteria belonging to the division Firmicutes. They occur in different ecosystems, rabbits including. Enterococci can possess probiotic properties and produce antimicrobial substances-bacteriocins. Rabbit meat as nutritionally healthy food offers novel source to study bacteriocin-producing and/or probiotic enterococci. Methodology and results: Enterococci were detected from rabbit meat samples (42. Most of the isolates were allotted to the species Enterococcus faecium by PCR method. The isolates have possessed the structural genes for enterocins A, P, B production. The inhibitory substances produced by the isolated enterococci inhibited the growth of 12 indicators. Of 34 isolates, 15 strains have shown the antimicrobial activity against L. monocytogenes CCM 4699, 12 strains against S. aureus 3A3, 10 strains against S. aureus 5A2 as well as Salmonella enterica serovar Enteritidis PT4. Moreover, enterococci have tolerated 5 % bile, low pH; they have produced lactid acid in the amount from 0.740 ± 0.091 to 1.720 ± 0.095 mmol/l. The isolates were mostly sensitive to antibiotics. Conclusion, significance and impact of study: Bacteriocin-producing strain E. faecium M3a has been selected for more detail characterization of its bacteriocin and probiotic properties with the aim for its further application as an additive.

  7. Strain measurement technique

    International Nuclear Information System (INIS)

    1987-01-01

    The 10 contributions are concerned with selected areas of application, such as strain measurements in wood, rubber/metal compounds, sets of strain measurements on buildings, reinforced concrete structures without gaps, pipes buried in the ground and measurements of pressure fluctuations. To increase the availability and safety of plant, stress analyses were made on gas turbine rotors with HT-DMS or capacitive HT-DMS (high temperature strain measurements). (DG) [de

  8. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  9. Predicting creep rupture from early strain data

    International Nuclear Information System (INIS)

    Holmstroem, Stefan; Auerkari, Pertti

    2009-01-01

    To extend creep life modelling from classical rupture modelling, a robust and effective parametric strain model has been developed. The model can reproduce with good accuracy all parts of the creep curve, economically utilising the available rupture models. The resulting combined model can also be used to predict rupture from the available strain data, and to further improve the rupture models. The methodology can utilise unfailed specimen data for life assessment at lower stress levels than what is possible from rupture data alone. Master curves for creep strain and rupture have been produced for oxygen-free phosphorus-doped (OFP) copper with a maximum testing time of 51,000 h. Values of time to specific strain at given stress (40-165 MPa) and temperature (125-350 deg. C) were fitted to the models in the strain range of 0.1-38%. With typical inhomogeneous multi-batch creep data, the combined strain and rupture modelling involves the steps of investigation of the data quality, extraction of elastic and creep strain response, rupture modelling, data set balancing and creep strain modelling. Finally, the master curves for strain and rupture are tested and validated for overall fitting efficiency. With the Wilshire equation as the basis for the rupture model, the strain model applies classical parametric principles with an Arrhenius type of thermal activation and a power law type of stress dependence for the strain rate. The strain model also assumes that the processes of primary and secondary creep can be reasonably correlated. The rupture model represents a clear improvement over previous models in the range of the test data. The creep strain information from interrupted and running tests were assessed together with the rupture data investigating the possibility of rupture model improvement towards lower stress levels by inverse utilisation of the combined rupture based strain model. The developed creep strain model together with the improved rupture model is

  10. Introducing lattice strain to graphene encapsulated in hBN

    Science.gov (United States)

    Tomori, Hikari; Hiraide, Rineka; Ootuka, Youiti; Watanabe, Kenji; Taniguchi, Takashi; Kanda, Akinobu

    Due to the characteristic lattice structure, lattice strain in graphene produces an effective gauge field. Theories tell that by controlling spatial variation of lattice strain, one can tailor the electronic state and transport properties of graphene. For example, under uniaxial local strain, graphene exhibits a transport gap at low energies, which is attractive for a graphene application to field effect devices. Here, we develop a method for encapsulating a strained graphene film in hexagonal boron-nitride (hBN). It is known that the graphene carrier mobility is significantly improved by the encapsulation of graphene in hBN, which has never been applied to strained graphene. We encapsulate graphene in hBN using the van der Waals assembly method. Strain is induced by sandwiching a graphene film between patterned hBN sheets. Spatial variation of strain is confirmed with micro Raman spectroscopy. Transport measurement of encapsulated strained graphene is in progress.

  11. Variation in the strain anisotropy of Zircaloy with temperature and strain

    International Nuclear Information System (INIS)

    Hindle, E.D.; Worswick, D.

    1984-04-01

    Strain anisotropy was investigated at temperatures in the range 293 to 1117K in circular tensile specimens prepared from rolled Zircaloy-2 plate so that their tensile axes were parallel to and transverse to the rolling direction. The strain anisotropy factor for both types of specimen increased markedly in the high alpha phase region above 923K reaching a maximum at circa 1070K. Above this temperature in the alpha-plus-beta phase region the strain anisotropy decreased rapidly as the proportion of beta phase increased and was almost non-existent at 1173K. The strain anisotropy was markedly strain dependent, particularly in the high alpha phase region. The study was extended to Zircaloy-4 pressurized water reactor (PWR) 17 x 17 type fuel rod tubing specimens which were strained under biaxial conditions using cooling conditions which promoted uniform diametral strain over most of their lengths (circa 250 mm). In these circumstances the strain anisotropy is manifest by a reduction in length. Measurement of this change along with that in diameter and wall thickness produced data from which the strain anisotropy factor was calculated. The results, although influenced by additional factors discussed in the paper, were similar to those observed in the uniaxial Zircaloy-2 tensile tests. (author)

  12. A strain gauge

    DEFF Research Database (Denmark)

    2017-01-01

    The invention relates to a strain gauge of a carrier layer and a meandering measurement grid (101) positioned on the carrier layer, wherein the measurement grid comprises a number of measurement grid sections placed side by side with gaps in between, and a number of end loops (106) interconnecting...... relates to a method for manufacturing a strain gauge as mentioned above....

  13. Producing ergosterol from corn straw hydrolysates using ...

    African Journals Online (AJOL)

    Ergosterol is an economically important metabolite produced by Saccharomyces cerevisiae. In this study, the production of ergosterol by the strain using corn straw as an inexpensive carbon source was investigated. The total yield of ergosterol was determined by both the biomass and ergosterol content in yeast cells which ...

  14. Chemical Profile of Monascus ruber Strains

    Directory of Open Access Journals (Sweden)

    Ahamed M. Moharram

    2012-01-01

    Full Text Available Chemical profile of Monascus ruber strains has been studied using gas chromatography-mass spectrometry (GC/MS analysis. The colour intensity of the red pigment and secondary metabolic products of two M. ruber strains (AUMC 4066 and AUMC 5705 cultivated on ten different media were also studied. Metabolic products can be classified into four categories: anticholesterol, anticancer, food colouring, and essential fatty acids necessary for human health. Using GC/MS, the following 88 metabolic products were detected: butyric acid and its derivatives (25 products, other fatty acids and their derivatives (19 products, pyran and its derivatives (22 products and other metabolites (22 products. Among these, 32 metabolites were specific for AUMC 4066 strain and 34 for AUMC 5705 strain, whereas 22 metabolites were produced by both strains on different tested substrates. Production of some metabolites depended on the substrate used. High number of metabolites was recorded in the red pigment extract obtained by both strains grown on malt broth and malt agar. Also, 42 aroma compounds were recorded (4 alcohols, 2 benzaldehydes, 27 esters, 3 lactones, 1 phenol, 1 terpenoid, 3 thiol compounds and acetate-3-mercapto butyric acid. Thin layer chromatography and GC/MS analyses revealed no mycotoxin citrinin in any media used for the growth of the two M. ruber strains.

  15. Probiotic attributes of autochthonous Lactobacillus rhamnosus strains of human origin.

    Science.gov (United States)

    Pithva, Sheetal; Shekh, Satyamitra; Dave, Jayantilal; Vyas, Bharatkumar Rajiv Manuel

    2014-05-01

    The study was aimed at evaluating the probiotic potential of indigenous autochthonous Lactobacillus rhamnosus strains isolated from infant feces and vaginal mucosa of healthy female. The survival of the selected strains and the two reference strains (L. rhamnosus GG and L. casei Actimel) was 67-81 % at pH 2 and 70-80 % after passage through the simulated gastrointestinal fluid. These strains are able to grow in the presence of 4 % bile salt, 10 % NaCl, and 0.6 % phenol. The cell surface of L. rhamnosus strains is hydrophilic in nature as revealed by bacterial adhesion to hydrocarbons (BATH) assay. Despite this, L. rhamnosus strains showed mucin adherence, autoaggregation and coaggregation properties that are strain-specific. In addition, they produce bile salt hydrolase (BSH) and β-galactosidase activities. L. rhamnosus strains exhibit antimicrobial activity against food spoilage organisms and gastrointestinal pathogens, as well as Candida and Aspergillus spp. L. rhamnosus strains have similar antibiotic susceptibility pattern, and resistance to certain antibiotics is intrinsic or innate. The strains are neither haemolytic nor producer of biogenic amines such as histamine, putrescine, cadaverine and tyramine. Lyophilized cells of L. rhamnosus Fb exhibited probiotic properties demonstrating potential of the strain for technological suitability and in the preparation of diverse probiotic food formulations.

  16. Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    DEFF Research Database (Denmark)

    Andersen, Mikael Rørdam; Salazar, Margarita Pena; Schaap, Peter J.

    2011-01-01

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme......-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15...

  17. A new strain of Claviceps purpurea accumulating tetracyclic clavine alkaloids.

    Science.gov (United States)

    Schumann, B; Erge, D; Maier, W; Gröger, D

    1982-05-01

    A new strain of Claviceps was isolated from a blokked mutant of Claviceps purpurea. This strain accumulates substantial amounts of clavine alkaloids (2 g/l). The alkaloid fraction is composed of chanoclavine-I ( approximately 10%) and a mixture of agroclavine/elymoclavine (90%). Most suitable for alkaloid production in submerged culture is an ammoncitrate/sucrose medium. The genealogy of the new strain, designated Pepty 695/ch-I is the following one: Pepty 695/S (ergotoxine producer) --> Pepty 695/ch (secoergoline producer) --> Pepty 695/ch-I (tetracyclic clavine producer).

  18. Penicillin production by mutant strains of penicillium chrysogenum

    International Nuclear Information System (INIS)

    Tawfik, Z.S.; Ashour, M.S.; Shihab, A.

    1986-01-01

    The mutagenic agent 8-rays was used to initiate the penicillium chrysogenum isolated from local spices. After irradiation, colonies invariably differing from the parent strain in their morphological and cultural characteristics were tested for antibiotic production on fermentation agar medium. Twenty two isolates were found to be penicillin producing mutant strains. Mutant strain M 24 forming small colonies with white conidia was found to be a high yielding penicillin producer (9550 i.u/ml). All of the 22 isolates obtained lost their ability to produce the antibiotic after 11 months storage at 4 0 with subsequent subculturing

  19. Bacteriocin-like inhibitory activities of seven Lactobacillus delbrueckii subsp. bulgaricus strains against antibiotic susceptible and resistant Helicobacter pylori strains.

    Science.gov (United States)

    Boyanova, L; Gergova, G; Markovska, R; Yordanov, D; Mitov, I

    2017-12-01

    The aim of the study was to detect anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains by four cell-free supernatant (CFS) types. Activity of non-neutralized and non-heat-treated (CFSs1), non-neutralized and heat-treated (CFSs2), pH neutralized, catalase-treated and non-heat-treated (CFSs3), or neutralized, catalase- and heat-treated (CFSs4) CFSs against 18 H. pylori strains (11 of which with antibiotic resistance) was evaluated. All GLB strains produced bacteriocin-like inhibitory substances (BLISs), the neutralized CFSs of two GLB strains inhibited >81% of test strains and those of four GLB strains were active against >71% of antibiotic resistant strains. Two H. pylori strains were BLIS resistant. The heating did not reduce the CFS activity. Briefly, all GLB strains evaluated produced heat-stable BLISs, although GLB and H. pylori strain susceptibility patterns exhibited differences. Bacteriocin-like inhibitory substance activity can be an advantage for the probiotic choice for H. pylori infection control. In this study, anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains was evaluated by four cell-free supernatant (CFS) types. The GLB strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity and some neutralized, catalase- and heat-treated CFSs inhibited >83% of the test strains. Bacteriocin-like inhibitory substance production of GLB strains can render them valuable probiotics in the control of H. pylori infection. © 2017 The Society for Applied Microbiology.

  20. Development of Bacillus subtilis mutants to produce tryptophan in pigs

    DEFF Research Database (Denmark)

    Bjerre, Karin; Cantor, Mette D.; Nørgaard, Jan Værum

    2017-01-01

    Objectives To generate tryptophan-overproducing Bacillus subtilis strains for in situ use in pigs, to reduce the feed cost for farmers and nitrogen pollution. Results A novel concept has been investigated—to generate B. subtilis strains able to produce tryptophan (Trp) in situ in pigs. Mutagenesis......-excreting B. subtilis strains were obtained with UV-mutagenesis and analogue selection and can be used in animal feed applications....

  1. Performance of baker's yeast produced using date syrup substrate ...

    African Journals Online (AJOL)

    Baker's yeast was produced from three selected baker's yeast strains using date syrup as a substrate at low and high flow rate compared to those produced using molasses substrates. Performance of the produced baker's yeasts on Arabic bread quality was investigated. Baking tests showed a positive relationship between ...

  2. Isolation of hydrogen-producing bacteria from biodigesters

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, S.V.; Servulo, E.F.C.; Da Silva, I.M.; Martelli, H.L.

    1984-01-01

    Two H2-producing strains belonging to the Enterobacteriaceae were isolated from biodigesters, fed sugarcane distillation slops, from acetone-butanol fermentation, under anaerobic conditions. H2 and CO2 were the only gases produced from glucose. H2 was 40.87% of the total gas produced by Citrobacter freundii, and 57.74% when Enterobacter agglomerans was assayed.

  3. Isolation, identification and biological characteristics of an exopolysaccharide-producing lactic acid bacteria strain from intestinal tract of black porgy (Sparus macrocephalus)%产胞外多糖的黑鲷肠道乳酸菌的分离鉴定及其生物学特性

    Institute of Scientific and Technical Information of China (English)

    戴贤君; 章蔚; 刘明启; 黄晓林

    2011-01-01

    通过常规鉴定和16S rDNA序列分析,从黑鲷(Sparus macrocephalus)肠道中分离鉴定出1株明串珠菌属(Leuconostoc)乳酸菌菌株;该分离株对酸、胆盐、蛋白酶具有良好耐受性,但对温度耐受能力较差;分离株培养上清液对哈维氏弧菌(Vibrio harveyi)、溶藻弧菌(Vibrio algnolyticus)、副溶血弧菌(Vibrio parahaemolyticus)的抑菌圈直径为1.12~1.22 cm,不同培养时间的抑菌效果差异无统计学意义(P>0.05);分离株在培养24、32、40、48和56 h时的胞外多糖质量浓度为167.24~184.45 mg·L-1,不同取样时间的胞外多糖质量浓度差异无统计学意义(P>0.05);灌服胞外多糖20 d后黑鲷血液的红细胞、白细胞数量和血红素浓度、淋巴细胞比率均显著升高(P<0.05).综上,该分离株为产胞外多糖的明串珠属乳酸菌,可作为开发海水鱼用微生态制剂的候选菌株.%A strain of exopolysaccharide-producing lactic acid bacteria was isolated from intestines of black porgy, Sparus macrocephalus, and was identified as Leuconostoc lactis by conventional biochemical characteristics, 16S rDNA gene sequence analysis. Physiological-biochemical tests for the isolate showed that it had good tolerance to acid, bile salt and protease, but couldn' t live above 70 ℃. The culture supernatant of the isolate could inhibit the growth of Vibrio parahaemolyticus, Vibrio harveyi and Vibrio alginolyticus, and the inhibition zone diameters were 1.12-1.22 cm and had not significant difference (P> 0.05) at different culture time of 24, 32, 40, 48, 56 h, The concentrations of exopolysaccharides in the culture medium were 167. 24-184.45 mg· L-1 with no significant difference (P>0. 05) at the culture time of 24, 32, 40, 48, 56 h. The erythrocyte and leukocyte counts,hemoglobin concentration and lymphocyte ratio of black porgies increased significantly (P<0. 05) after being fed orally exopolysaccharides from the isolate culture for 20 d. The results above

  4. Isolation and characterization of new strains of cholesterol-reducing bacteria from baboons.

    Science.gov (United States)

    Brinkley, A W; Gottesman, A R; Mott, G E

    1982-01-01

    We isolated and characterized nine new strains of cholesterol-reducing bacteria from feces and intestinal contents of baboons. Cholesterol-brain agar was used for the primary isolation, and subsequent biochemical tests were done in a lecithin-cholesterol broth containing plasmenylethanolamine and various substrates. All strains had similar colony and cell morphology, hydrolyzed the beta-glucosides esculin and amygdalin, metabolized pyruvate, and produced acetate and acetoin. Unlike previously reported strains, the nine new strains did not require cholesterol and an alkenyl ether lipid (e.g., plasmalogen) for growth; however, only two strains reduced cholesterol in the absence of the plasmalogen. These two strains also produced succinate as an end product. Carbohydrate fermentation was variable; some strains produced weak acid (pH 5.5 to 6.0) from only a few carbohydrates, whereas other strains produced strong acid reactions (pH less than or equal to 5.5) from a wide variety of carbohydrates.

  5. Characterization of Bacillus subtilis strains in Thua nao, a traditional fermented soybean food in northern Thailand.

    Science.gov (United States)

    Inatsu, Y; Nakamura, N; Yuriko, Y; Fushimi, T; Watanasiritum, L; Kawamoto, S

    2006-09-01

    To clarify the diversity of Bacillus subtilis strains in Thua nao that produce high concentrations of products useful in food manufacturing and in health-promoting compounds. Production of amylase, protease, subtilisin NAT (nattokinase), and gamma-polyglutamic acid (PGA) by the Bacillus subtilis strains in Thua nao was measured. Productivity of protease NAT by these strains tended to be higher than by Japanese commercial natto-producing strains. Molecular diversity of isolated strains was analysed via randomly amplified polymorphic DNA-PCR fingerprinting. The strains were divided into 19 types, including a type with the same pattern as a Japanese natto-producing strain. B. subtilis strains that could be a resource for effective production of protease, amylase, subtilisin NAT, or PGA were evident in Thua nao produced in various regions in northern Thailand. This study clearly demonstrated the value of Thua nao as a potential resource of food-processing enzymes and health-promoting compounds.

  6. Potential of Bacillus spp produces siderophores insuppressing thewilt disease of banana plants

    Science.gov (United States)

    Kesaulya, H.; Hasinu, J. V.; Tuhumury, G. NC

    2018-01-01

    In nature, different types of siderophore such as hydroxymate, catecholets and carboxylate, are produced by different bacteria. Bacillus spp were isolated from potato rhizospheric soil can produce siderophore of both catecholets and salicylate type with different concentrations. Various strains of Bacillus spp were tested for pathogen inhibition capability in a dual culture manner. The test results showed the ability of inhibition of pathogen isolated from banana wilt disease. From the result tested were found Bacillus niabensis Strain PT-32-1, Bacillus subtilis Strain SWI16b, Bacillus subtilis Strain HPC21, Bacillus mojavensis Strain JCEN3, and Bacillus subtilis Strain HPC24 showed different capabilities in suppressing pathogen.

  7. Internally Mounting Strain Gages

    Science.gov (United States)

    Jett, J. R., Jr.

    1984-01-01

    Technique for mounting strain gages inside bolt or cylinder simultaneously inserts gage, attached dowel segment, and length of expandable tubing. Expandable tubing holds gage in place while adhesive cures, assuring even distribution of pressure on gage and area gaged.

  8. Strain preservation of experimental animals: vitrification of two-cell stage embryos for multiple mouse strains.

    Science.gov (United States)

    Eto, Tomoo; Takahashi, Riichi; Kamisako, Tsutomu

    2015-04-01

    Strain preservation of experimental animals is crucial for experimental reproducibility. Maintaining complete animal strains, however, is costly and there is a risk for genetic mutations as well as complete loss due to disasters or illness. Therefore, the development of effective vitrification techniques for cryopreservation of multiple experimental animal strains is important. We examined whether a vitrification method using cryoprotectant solutions, P10 and PEPeS, is suitable for preservation of multiple inbred and outbred mouse strains. First, we investigated whether our vitrification method using cryoprotectant solutions was suitable for two-cell stage mouse embryos. In vitro development of embryos exposed to the cryoprotectant solutions was similar to that of fresh controls. Further, the survival rate of the vitrified embryos was extremely high (98.1%). Next, we collected and vitrified two-cell stage embryos of 14 mouse strains. The average number of embryos obtained from one female was 7.3-33.3. The survival rate of vitrified embryos ranged from 92.8% to 99.1%, with no significant differences among mouse strains. In vivo development did not differ significantly between fresh controls and vitrified embryos of each strain. For strain preservation using cryopreserved embryos, two offspring for inbred lines and one offspring for outbred lines must be produced from two-cell stage embryos collected from one female. The expected number of surviving fetuses obtained from embryos collected from one female of either the inbred or outbred strains ranged from 2.9 to 19.5. The findings of the present study indicated that this vitrification method is suitable for strain preservation of multiple mouse strains. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  9. An update on organohalogen metabolites produced by basidiomycetes

    NARCIS (Netherlands)

    Field, J.A.; Wijnberg, J.B.P.A.

    2003-01-01

    Basidiomycetes are an ecologically important group of higher fungi known for their widespread capacity to produce organohalogen metabolites. To date, 100 different organohalogen metabolites (mostly chlorinated) have been identified from strains in 70 genera of Basidiomycetes. This manuscript

  10. Mycotoxin producing potential of some isolates of Aspergillus flavus and Eurotium groups from meat products.

    Science.gov (United States)

    el-Kady, I; el-Maraghy, S; Zohri, A N

    1994-09-01

    All strains (92) of A. flavus group proved to be positive for production of aflatoxin (45 to 1200 micrograms/50 ml medium) on potato dextrose liquid medium, while 59 strains only proved to be positive (35-310 micrograms/50 ml) on 15% NaCl potato-dextrose liquid medium. Most of the strains tested of A. flavus, A. flavus var. columnaris and A. oryzae produced aflatoxins B1, B2, G1 & G2. All positive strains of A. tamarii produced aflatoxins G1 & G2 while the tested isolate of A. zonatus produced aflatoxins B1 & G1. Of 95 strains tested of Eurotium, aflatoxins B1 & G1 were produced by one strain of each of E. chevalieri var. intermedium, E. repens and E. rubrum. Gliotoxin was detected in the extract of two strains of E. chevalieri and one strain of each of E. chevalieri var. intermedium and E. pseudoglaucum on the salt-free medium, and two strains of each of E. chevalieri, E. chevalieri var. intermedium and one of E. pseudoglaucum on 15% NaCl medium. Sterigmatocystin was produced by some strains of E. chevalieri, E. chevalieri var. intermedium, E. amstelodami, E. pseudoglaucum and E. rubrum on the two experimental media. One strain only of E. repens produced ochratoxin A while citrinin was detected in the extract of one strain of E. pseudoglaucum.

  11. Mead production: selection and characterization assays of Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Pereira, Ana Paula; Dias, Teresa; Andrade, João; Ramalhosa, Elsa; Estevinho, Letícia M

    2009-08-01

    Mead is a traditional drink, which results from the alcoholic fermentation of diluted honey carried out by yeasts. However, when it is produced in a homemade way, mead producers find several problems, namely, the lack of uniformity in the final product, delayed and arrested fermentations, and the production of "off-flavours" by the yeasts. These problems are usually associated with the inability of yeast strains to respond and adapt to unfavourable and stressful growth conditions. The main objectives of this work were to evaluate the capacity of Saccharomyces cerevisiae strains, isolated from honey of the Trás-os-Montes (Northeast Portugal), to produce mead. Five strains from honey, as well as one laboratory strain and one commercial wine strain, were evaluated in terms of their fermentation performance under ethanol, sulphur dioxide and osmotic stress. All the strains showed similar behaviour in these conditions. Two yeasts strains isolated from honey and the commercial wine strain were further tested for mead production, using two different honey (a dark and a light honey), enriched with two supplements (one commercial and one developed by the research team), as fermentation media. The results obtained in this work show that S. cerevisiae strains isolated from honey, are appropriate for mead production. However it is of extreme importance to take into account the characteristics of the honey, and supplements used in the fermentation medium formulation, in order to achieve the best results in mead production.

  12. Flexible piezotronic strain sensor.

    Science.gov (United States)

    Zhou, Jun; Gu, Yudong; Fei, Peng; Mai, Wenjie; Gao, Yifan; Yang, Rusen; Bao, Gang; Wang, Zhong Lin

    2008-09-01

    Strain sensors based on individual ZnO piezoelectric fine-wires (PFWs; nanowires, microwires) have been fabricated by a simple, reliable, and cost-effective technique. The electromechanical sensor device consists of a single electrically connected PFW that is placed on the outer surface of a flexible polystyrene (PS) substrate and bonded at its two ends. The entire device is fully packaged by a polydimethylsiloxane (PDMS) thin layer. The PFW has Schottky contacts at its two ends but with distinctly different barrier heights. The I- V characteristic is highly sensitive to strain mainly due to the change in Schottky barrier height (SBH), which scales linear with strain. The change in SBH is suggested owing to the strain induced band structure change and piezoelectric effect. The experimental data can be well-described by the thermionic emission-diffusion model. A gauge factor of as high as 1250 has been demonstrated, which is 25% higher than the best gauge factor demonstrated for carbon nanotubes. The strain sensor developed here has applications in strain and stress measurements in cell biology, biomedical sciences, MEMS devices, structure monitoring, and more.

  13. Characterization of Bacillus thuringiensis strains from Jordan and ...

    African Journals Online (AJOL)

    Eight serotypes with Bacillus thuringiensis israelensis being the most common. Out of the twenty-six isolated strains, five strains (serotype: kenyae, kurstaki, kurstaki HD1 and thuringiensis) that produced bipyramid crystal proteins were toxic to the lepidoptera larvae of Ephestia kuehniella Zeller. The SDS-PAGE protein ...

  14. Changes occurring in plain, straining and winter yoghurt during the ...

    African Journals Online (AJOL)

    In this study, winter yoghurt, straining yoghurt and yoghurt samples produced from homogenized and non-homogenized sheep and a mixture of sheep and cows milks were evaluated during the storage periods. Winter yoghurt, straining yoghurt and yoghurt samples were stored in sterile jars in the refrigerator (4°C).

  15. Gender, General Strain Theory, Negative Emotions, and Disordered Eating

    Science.gov (United States)

    Piquero, Nicole Leeper; Fox, Kristan; Piquero, Alex R.; Capowich, George; Mazerolle, Paul

    2010-01-01

    Much of the prior work on General Strain Theory (GST) has focused on how strain and negative emotions interrelate to produce criminal--especially violent--activity. Very little research has extended GST to examine other types of non-criminal, negative behavior, such as self-harming behaviors associated with disordered eating, a traditionally…

  16. Highly hydrolytic reuteransucrase from probiotic Lactobacillus reuteri strain ATCC 55730

    NARCIS (Netherlands)

    Kralj, S.; Stripling, E.; Sanders, P.; Geel-Schutten, G.H. van; Dijkhuizen, L.

    2005-01-01

    Lactobacillus reuteri strain ATCC 55730 (LB BIO) was isolated as a pure culture from a Reuteri tablet purchased from the BioGaia company. This probiotic strain produces a soluble glucan (reuteran), in which the majority of the linkages are of the α-(1→4) glucosidic type (∼70%). This reuteran also

  17. Strain distribution during tensile deformation of nanostructured aluminum samples

    DEFF Research Database (Denmark)

    Kidmose, Jacob; Lu, L.; Winther, Grethe

    2012-01-01

    To optimize the mechanical properties, especially formability, post-process deformation by cold rolling in the range 5–50 % reduction was applied to aluminum sheets produced by accumulative roll bonding to an equivalent strain of 4.8. During tensile testing high resolution maps of the strain...

  18. Comparison of the adhesion ability of Candida albicans strains to ...

    African Journals Online (AJOL)

    The purpose of the present study is to investigate the ability of oral Candida albicans strains to adhere to Caco-2 and Hep-2 epithelial cells, to produce slime using Congo red and Safranin methods and to form a biofilm on polymethylmethacrylate. A total of 20 C. albicans strains were tested in the present work. The biofilm ...

  19. Formation of biofilm by strains of Listeria monocytogenes isolated ...

    African Journals Online (AJOL)

    Quantification of biofilm formation by 40 Listeria monocytogenes strains from wara soft cheese and its processing environment was assessed on glass vials surfaces. Attachement to glass surface was quantified using a crystal violet binding assay. All the 40 strains produced biofilms after 48 and 72 h incubation at 37oC.

  20. Antimicrobial drug susceptibility of Neisseria meningitidis strains isolated from carriers

    Directory of Open Access Journals (Sweden)

    Dayamí García

    2000-06-01

    Full Text Available When it is necessary to determine the susceptibility of Neisseria meningitidis (Nm strains to antimicrobial drugs, it is important to consider that it should be analyzed in a double context. One of them related to the use of drugs in a specific medical treatment; and the other; to chemoprophylatic drugs, both with the same purpose: the accurate selection of the “in vivo” antimicrobial agent. This requires the study of the sensitivity and resistance of strains isolated in both carriers and patients. With the aim of further studying the behavior of the strains that currently circulate in Cuba, an antimicrobial drug susceptibility study was conducted in 90 strains isolated from carriers during the first half of 1998. The agar dilution method was used to determine the minimum inhibitory concentrations (MICs to: penicillin, ampicillin, rifampin, sulfadiazine, chloramphenicol, ciprofloxacin, ceftriaxone, cefotaxime. The study of the three latter drugs was done for the first time in our country. The search for β- lactamase-producer strains was also performed. There was a predominance of penicillin sensitive strains (82,2% with an intermediate sensitivity to ampicillin (57,8%, while 70% of the strains were sensitive to sulfadiazine. Regarding the rest of the antimicrobial drugs, 100% of the strains were sensitive. The paper shows the MICs for each drug as well as the phenotypic characteristics of the strains with the penicillin and sulfadiazine sensitivity and resistance patterns. No β-lactamase-producer strains were found.

  1. Rheology of spreadable goat cheese made with autochthonous lactic cultures differing in their ability to produce exopolysaccharides

    Directory of Open Access Journals (Sweden)

    Frau Silvia Florencia

    2013-06-01

    Full Text Available The aim of this study was to compare the rheology of spreadable cheeses elaborated with autochthonous lactic starter cultures without the addition of exopolysaccharide-producing strain in the same starter with exopolysaccharide-producing strain. From a rheological standpoint, both samples were characterized as weak viscoelastic gels and pseudoplastic products. It was concluded that cheese made with exopolysaccharide-producing strain showed smaller G', G", and η* values over the range of frequencies studied and smaller critic stress values than the cheese without exopolysaccharide-producing strain. The results obtained indicate that cheeses without exopolysaccharide-producing strain need to be added with any texture enhancer product.

  2. Revealing differences in metabolic flux distributions between a mutant strain and its parent strain Gluconacetobacter xylinus CGMCC 2955.

    Directory of Open Access Journals (Sweden)

    Cheng Zhong

    Full Text Available A better understanding of metabolic fluxes is important for manipulating microbial metabolism toward desired end products, or away from undesirable by-products. A mutant strain, Gluconacetobacter xylinus AX2-16, was obtained by combined chemical mutation of the parent strain (G. xylinus CGMCC 2955 using DEC (diethyl sulfate and LiCl. The highest bacterial cellulose production for this mutant was obtained at about 11.75 g/L, which was an increase of 62% compared with that by the parent strain. In contrast, gluconic acid (the main byproduct concentration was only 5.71 g/L for mutant strain, which was 55.7% lower than that of parent strain. Metabolic flux analysis indicated that 40.1% of the carbon source was transformed to bacterial cellulose in mutant strain, compared with 24.2% for parent strain. Only 32.7% and 4.0% of the carbon source were converted into gluconic acid and acetic acid in mutant strain, compared with 58.5% and 9.5% of that in parent strain. In addition, a higher flux of tricarboxylic acid (TCA cycle was obtained in mutant strain (57.0% compared with parent strain (17.0%. It was also indicated from the flux analysis that more ATP was produced in mutant strain from pentose phosphate pathway (PPP and TCA cycle. The enzymatic activity of succinate dehydrogenase (SDH, which is one of the key enzymes in TCA cycle, was 1.65-fold higher in mutant strain than that in parent strain at the end of culture. It was further validated by the measurement of ATPase that 3.53-6.41 fold higher enzymatic activity was obtained from mutant strain compared with parent strain.

  3. Brookhaven Linac Isotope Producer

    Data.gov (United States)

    Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

  4. Studies on Drosophila radiosensitivity strains

    International Nuclear Information System (INIS)

    Varentsova, E.R.; Sharygin, V.I.; Khromykh, Yu.U.

    1985-01-01

    Fertility of radiosensitive mutant drosophila female strain rad (2) 201 61 after irradiation and frequency of dominant lethal mutations (DLM), induced by γ-radiation for 0-5 h and 5-7 days, are investigated. It is shown, that oocytes of the mutant strain are more radiosensitive as compared with cells of mongrel flies as to criterion of DLM appearance over the period of maturing. Early oocytes of stages 2-7 are the most sensitive, i.e. at the stages, corresponding to the manifestation of previously established recombination-defective properties of mutations rad (2) 201 61 . It is also sown, that doses of γ-rays, exceeding 10 Gy produce a strong sterilizing effect on mutant females due to destruction and resorption of egg chambers, irradiated at the stages of previtellogenetic growth of oocytes. In females, carrying mutation of radiosensitivity there is no direct correlation betwen sensitivity of oocytes proper to DLM induction and sensitivity of egg folleicles to resorbing effect of γ-rays. The ways of possible involvement of mutant locus studied into genetic processes in various specialized cells of drosophila

  5. Producing charcoal from wastes

    Energy Technology Data Exchange (ETDEWEB)

    Pogorelov, V.A.

    1983-01-01

    Experimental works to use wood wastes for producing charcoal are examined, which are being conducted in the Sverdlovsk assembly and adjustment administration of Soyuzorglestekhmontazh. A wasteless prototype installation for producing fine charcoal is described, along with its subsequent briqueting, which is made on the basis of units which are series produced by the factories of the country. The installation includes subassemblies for preparing and drying the raw material and for producing the charcoal briquets. In the opinion of specialists, the charcoal produced from the wastes may be effectively used in ferrous and nonferrous metallurgy and in the production of pipes.

  6. Analysis of potential fumonisin-producing Fusarium species in corn products from three main maize-producing areas in eastern China.

    Science.gov (United States)

    Zhang, Liping; Wang, Jiansheng; Zhang, Chulong; Wang, Qiaomei

    2013-02-01

    Fusarium species are common fungal contaminants of maize and a number of them can produce mycotoxin fumonisins. China is one of the largest maize producers in the world. This study investigated the contamination of maize samples from three areas in eastern China by Fusarium and fumonisin-producing fungi as well as their fumonisin-producing potential. A total of 22 Fusarium strains were isolated, 19 of which were able to produce fumonisin. Among the 19 strains, 16 belonged to F. verticillioides, two to F. subglutinans and one to F. proliferatum. The majority (17/19) of the fumonisin-forming strains were high FB(1) producers, which is a potential health risk for the population in these areas. Fusarium contamination in samples from the mideastern area was the most serious (11 Fusarium strains, with nine producing fumonisin, isolated from 24 samples), followed by the northeastern area (nine Fusarium strains, with all nine producing fumonisin, isolated from 21 samples) and the southeastern area (two Fusarium strains, with one producing fumonisin, isolated from 19 samples). Although the overall levels of FBs and contamination by fumonisin-producing fungi in corn samples were not serious, the contaminating Fusarium strains possessed fairly strong toxicogenic ability and potential risk for food safety. Copyright © 2012 Society of Chemical Industry.

  7. Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers

    Directory of Open Access Journals (Sweden)

    Juan Puño-Sarmiento

    2014-08-01

    Full Text Available The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%, three strains as Shiga toxin-producing (STEC; 4.7%, 10 strains as enteroaggregative (EAEC; 12.5%, but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  8. Identification of diarrheagenic Escherichia coli strains from avian organic fertilizers.

    Science.gov (United States)

    Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

    2014-08-28

    The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  9. Biopesticide activity of sugarcane associated rhizobacteria: Ochrobactrum intermedium strain NH-5 and Stenotrophomonas maltophilia strain NH-300 against red rot under field conditions

    Directory of Open Access Journals (Sweden)

    Muhammad Nadeem HASSAN

    2014-09-01

    Full Text Available Colletotrichum falcatum is the major fungal pathogen causing sugarcane red rot. Four antagonistic bacterial strains exhibiting biocontrol activity against this pathogen in greenhouse conditions were characterized for production of different antifungal metabolites and biocontrol determinants to elucidate the mechanism of action involved in their antagonistic activity. The strains were also evaluated under field conditions to assess their biocontrol potential. All the strains produced hydrogen cyanide (HCN, and volatile and diffusible antibiotics. In addition, the Ochrobactrum intermedium strain NH-5 produced siderophores and the broad spectrum antibiotic 2, 4-diacetylphloroglucinol (2,4-DAPG; Pseudomonas sp. NH-203 produced siderophores, and Pseudomonas sp. NH-276 produced protease. Two strains, Ochrobactrum intermedium NH-5 and Stenotrophomonas maltophilia NH-300, exhibited good biocontrol activity, suppressing red rot by 44–52% on two sugarcane varieties, SPF-234 and Co-1148, in field experiments. The strains gave consistent results in three consecutive years and showed potential to be used as biopesticides.

  10. Aislamiento de Escherichia coli productor de toxina Shiga durante un brote de gastroenteritis en un Jardín Maternal de la Ciudad de Mar del Plata Isolation of Shiga toxin-producing Escherichia coli strains during a gastrointestinal outbreak at a day care center in Mar del Plata City

    Directory of Open Access Journals (Sweden)

    D. Gomez

    2005-12-01

    considered risk factors. One case had Shiga toxin-producing Escherichia coli (STEC O103:H2 infection and other STEC O26:H11.The duration of shedding for the child with O26:H11 infection was 37 days. In the other symptomatic children, the pathogen was not recovered from fecal samples collected 6 or more days after the onset of the illness. This emphasizes that the collection of early samples is necessary to recover STEC strains. In order to prevent and control enteric diseases in day care facilities the following measures are necessary: optimal hygiene standards, early case reporting, and exclusion of those who remain culture-positive.

  11. Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates

    Science.gov (United States)

    An industrial ethanol-producing Saccharomyces cerevisiae strain with genes needed for xylose-fermentation integrated into its genome was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than their parental strain (p < 0.05) and abl...

  12. Strains and Sprains

    Science.gov (United States)

    ... lot of pressure on a muscle or you push it too far, such as when lifting a heavy object. Strains may be more likely to happen if you haven't warmed up first to get blood circulating to the muscles. They're also common for someone returning to a sport after the off-season. That first time playing ...

  13. Investigate Nasal Colonize Staphylococcus Species Biofilm Produced

    Directory of Open Access Journals (Sweden)

    Cemil Demir

    2014-03-01

    Full Text Available Aim: 127 S.aureus and 65 CoNS strains were isolated from patients noses%u2019. To produce a biofilm ability was investigated using three different methods. Slime-positive and negative staphylococcies%u2019 resistance were evaluated against different antibiotics. Material and Method: Swap samples puted 7% blood agar. Staphylococcus aureus and coagulase-negative staphylococci (CoNS isolates biofilm produced ability were investigated using Congo Red Agar (CRA, microplates (MP and Standard Tube (ST methods. In addition to that, presence of antibiotic resistance of the staphylococcal isolates are determined agar disc diffusion method. Results: The rate of biofilm producing Staphylococcus spp strains was found to be 72.4%, 67.7%, and 62.9%, respectively with CRA, MP, and ST tests. There was no significant relationship among the tests (p>0.05. In addition, antibiotic resistance of Staphylococcus spp. against various antibiotics was also determined by the agar disk diffusion method. Resistance rates of biofilm positive (BP Staphylococcus spp for penicilin G, ampicilin, amocycilin/clavulanic acid, tetracyclin, eritromycin, gentamycin, and enrofloxacin 71.7%, 69.7%, 6.2%, 20.7%, 21.4%, 1.4%, and 0.7%, respectively. Resistance rates of biofilm negative (BN spp for 42.6%, 23.4%, 4.3%, 14.9%, 19.1%, 0.0%, 0.0% respectively. All Staphylococcus isolates were found to be susceptible to vancomycin and teicaplonin. Although BP strains antibiotic resistance rates were observed higher than BN strains. But resistance rates were not found statistically significant (p>0.05. Discussion: CRA is the reliablity and specifity method to determine Staphylococcus spp. biofilm produce ability.

  14. Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms.

    Science.gov (United States)

    Yamanaka, Takeshi; Yamane, Kazuyoshi; Furukawa, Tomoyo; Matsumoto-Mashimo, Chiho; Sugimori, Chieko; Nambu, Takayuki; Obata, Noboru; Walker, Clay B; Leung, Kai-Poon; Fukushima, Hisanori

    2011-08-25

    Evidence in the literature suggests that exopolysaccharides (EPS) produced by bacterial cells are essential for the expression of virulence in these organisms. Secreted EPSs form the framework in which microbial biofilms are built. This study evaluates the role of EPS in Prevotella intermedia for the expression of virulence. This evaluation was accomplished by comparing EPS-producing P. intermedia strains 17 and OD1-16 with non-producing P. intermedia ATCC 25611 and Porphyromonas gingivalis strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis. EPS-producing P. intermedia strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 107 colony-forming units (CFU). In comparison, P. intermedia ATCC 25611 and P. gingivalis ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (109 CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, P. intermedia strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes. These results demonstrate that the production of EPS by P. intermedia strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.

  15. Brittle superconducting magnets: an equivilent strain model

    International Nuclear Information System (INIS)

    Barzi, E.; Danuso, M.

    2010-01-01

    To exceed fields of 10 T in accelerator magnets, brittle superconductors like A15 Nb 3 Sn and Nb 3 Al or ceramic High Temperature Superconductors have to be used. For such brittle superconductors it is not their maximum tensile yield stress that limits their structural resistance as much as strain values that provoke deformations in their delicate lattice, which in turn affect their superconducting properties. Work on the sensitivity of Nb 3 Sn cables to strain has been conducted in a number of stress states, including uniaxial and multi-axial, producing usually different results. This has made the need of a constituent design criterion imperative for magnet builders. In conventional structural problems an equivalent stress model is typically used to verify mechanical sou