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Sample records for related bacteria photorhabdus

  1. Ail and PagC-related proteins in the entomopathogenic bacteria of Photorhabdus genus.

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    Annabelle Mouammine

    Full Text Available Among pathogenic Enterobacteriaceae, the proteins of the Ail/OmpX/PagC family form a steadily growing family of outer membrane proteins with diverse biological properties, potentially involved in virulence such as human serum resistance, adhesion and entry into eukaryotic culture cells. We studied the proteins Ail/OmpX/PagC in the bacterial Photorhabdus genus. The Photorhabdus bacteria form symbiotic complexes with nematodes of Heterorhabditis species, associations which are pathogenic to insect larvae. Our phylogenetic analysis indicated that in Photorhabdus asymbiotica and Photorhabdus luminescens only Ail and PagC proteins are encoded. The genomic analysis revealed that the Photorhabdus ail and pagC genes were present in a unique copy, except two ail paralogs from P. luminescens. These genes, referred to as ail1Pl and ail2Pl, probably resulted from a recent tandem duplication. Surprisingly, only ail1Pl expression was directly controlled by PhoPQ and low external Mg2+ conditions. In P. luminescens, the magnesium-sensing two-component regulatory system PhoPQ regulates the outer membrane barrier and is required for pathogenicity against insects. In order to characterize Ail functions in Photorhabdus, we showed that only ail2Pl and pagCPl had the ability, when expressed into Escherichia coli, to confer resistance to complement in human serum. However no effect in resistance to antimicrobial peptides was found. Thus, the role of Ail and PagC proteins in Photorhabdus life cycle is discussed.

  2. A functional MSBBA cyltransferaseof photorhabdus luminescens, required for secondary lipid aacylation in gram-negative bacteria,confers resistance to anti-microbial peptides

    International Nuclear Information System (INIS)

    Abi Khattar, Z.; Gaudriault, S.; Givaudan, A.

    2016-01-01

    Lipid A is a potent endotoxin, and its fatty acids (lauric, myristic, and sometimes palmitic acid) anchors lipopolysaccharide (LPS) into the outer leaflet of the outer membrane of most Gram-negative bacteria. The highly anionic charge of the glucosamine lipid A moiety makes the LPS a powerful attractant for cationic antimicrobial peptides (AMPs). AMPs are major component of innate immunity that kill bacteria by permeabilization of lipid bilayers. Secondary lipid A acylation of Klebsiella pneumoniae, involving the acyltransferase LpxM (formally, msbBor WaaN) that acylates (KDO)2-(lauroyl)-lipid IV-A with myristate during lipid A biosynthesis, has been associated with bacterial resistanceto AMPs contributing to virulence in animal models. We investigated here the role of the msbB gene of the entomopathogenic bacterium Photorhabdus luminescens in AMP resistance, by functional complementation of the AMP susceptible K. pneumoniae lpxM mutant with the P. luminescens msbB gene. We showed that msbB (lpxM) gene of P. luminescensis able to enhance polymyxin B, colistin and cecropin A resistance of K. pneumoniae lpxM mutant, compared to the non-complemented mutant. However, we could not obtain any msbB mutant of Photorhabdus by performing allelic exchange experiments based on positive selection of sucrose highly resistant mutants.We thus suggest that msbB-mediated Photorhabdus lipid A acylation is essential for outer membrane low-permeability and thatmodification of lipid A composition, fluidity and osmosis-resistance have an important role in the ability of Photorhabdus to grow in sucrose at high concentrations. (author)

  3. PirAB Toxin from Photorhabdus asymbiotica as a Larvicide against Dengue Vectors▿

    OpenAIRE

    Ahantarig, Arunee; Chantawat, Nantarat; Waterfield, Nicholas R.; ffrench-Constant, Richard; Kittayapong, Pattamaporn

    2009-01-01

    We have evaluated Photorhabdus insect-related protein (Pir) from Photorhabdus asymbiotica against dengue vectors. PirAB shows larvicidal activity against both Aedes aegypti and Aedes albopictus larvae but did not affect the Mesocyclops thermocyclopoides predator. PirAB expressed the strongest toxicity compared to PirA, PirB, or the mixture of PirA plus PirB. Whether the presence of an enterobacterial repetitive intergenic consensus sequence in PirAB, but not in PirA, PirB, or the mixture of P...

  4. From Insect to Man: Photorhabdus Sheds Light on the Emergence of Human Pathogenicity.

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    Geraldine Mulley

    Full Text Available Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates. In contrast, P. asymbiotica must necessarily be able to replicate at 37°C or above. Many well-studied mammalian pathogens use the elevated temperature of their host as a signal to regulate the necessary changes in gene expression required for infection. Here we use RNA-seq, proteomics and phenotype microarrays to examine temperature dependent differences in transcription, translation and phenotype of P. asymbiotica at 28°C versus 37°C, relevant to the insect or human hosts respectively. Our findings reveal relatively few temperature dependant differences in gene expression. There is however a striking difference in metabolism at 37°C, with a significant reduction in the range of carbon and nitrogen sources that otherwise support respiration at 28°C. We propose that the key adaptation that enables P. asymbiotica to infect humans is to aggressively acquire amino acids, peptides and other nutrients from the human host, employing a so called "nutritional virulence" strategy. This would simultaneously cripple the host immune response while providing nutrients sufficient for reproduction. This might explain the severity of ulcerated lesions observed in clinical cases of Photorhabdosis. Furthermore, while P. asymbiotica can invade mammalian cells they must also resist immediate killing by humoral immunity components in serum. We observed an increase in the production of the insect Phenol-oxidase inhibitor Rhabduscin normally deployed to inhibit the melanisation immune cascade. Crucially we demonstrated this molecule also facilitates protection against killing by the alternative human complement pathway.

  5. Structure of a cupin protein Plu4264 from Photorhabdus luminescens subsp. laumondii TTO1 at 1.35 Å resolution: Cupin Structure from Photorhabdus luminescens

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    Weerth, R. Sophia [Department of Bacteriology, University of Wisconsin-Madison, Madison Wisconsin; Michalska, Karolina [Midwest Center for Structural Genomics, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Bingman, Craig A. [Department of Biochemistry, University of Wisconsin-Madison, Madison Wisconsin; Yennamalli, Ragothaman M. [Biosciences at Rice, Rice University, Houston Texas; Li, Hui [Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Jedrzejczak, Robert [Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Wang, Fengbin [Biosciences at Rice, Rice University, Houston Texas; Babnigg, Gyorgy [Midwest Center for Structural Genomics, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Joachimiak, Andrzej [Midwest Center for Structural Genomics, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne Illinois; Thomas, Michael G. [Department of Bacteriology, University of Wisconsin-Madison, Madison Wisconsin; Phillips, George N. [Biosciences at Rice, Rice University, Houston Texas

    2014-12-18

    Proteins belonging to the cupin superfamily have a wide range of catalytic and noncatalytic functions. Cupin proteins commonly have the capacity to bind a metal ion with the metal frequently determining the function of the protein. We have been investigating the function of homologous cupin proteins that are conserved in more than 40 species of bacteria. To gain insights into the potential function of these proteins we have solved the structure of Plu4264 from Photorhabdus luminescens TTO1 at a resolution of 1.35 Å and identified manganese as the likely natural metal ligand of the protein.

  6. Photorhabdus adhesion modification protein (Pam) binds extracellular polysaccharide and alters bacterial attachment

    LENUS (Irish Health Repository)

    Jones, Robert T

    2010-05-12

    Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C) and human (37°C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of

  7. Photorhabdus adhesion modification protein (Pam) binds extracellular polysaccharide and alters bacterial attachment.

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    Jones, Robert T; Sanchez-Contreras, Maria; Vlisidou, Isabella; Amos, Matthew R; Yang, Guowei; Muñoz-Berbel, Xavier; Upadhyay, Abhishek; Potter, Ursula J; Joyce, Susan A; Ciche, Todd A; Jenkins, A Toby A; Bagby, Stefan; Ffrench-Constant, Richard H; Waterfield, Nicholas R

    2010-05-12

    Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28 degrees C) and human (37 degrees C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of EPS properties. Despite

  8. Photorhabdus adhesion modification protein (Pam binds extracellular polysaccharide and alters bacterial attachment

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    Joyce Susan A

    2010-05-01

    Full Text Available Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C and human (37°C temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect

  9. Transcript Abundance of Photorhabdus Insect-Related (Pir Toxin in Manduca sexta and Galleria mellonella Infections

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    Anaïs Castagnola

    2016-09-01

    Full Text Available In this study, we assessed pirAB toxin transcription in Photorhabdus luminescens laumondii (strain TT01 (Enterobacteriaceae by comparing mRNA abundance under in vivo and in vitro conditions. In vivo assays considered both natural and forced infections with two lepidopteran hosts: Galleria mellonella and Manduca sexta. Three portals of entry were utilized for the forced infection assays: (a integument; (b the digestive route (via mouth and anus; and (c the tracheal route (via spiracles. We also assessed plu4093-2 transcription during the course of a natural infection; this is when the bacteria are delivered by Heterorhabditis bacteriophora nematodes. Transcript abundance in G. mellonella was higher than in M. sexta at two of the observed time points: 15 and 18 h. Expression of pirAB plu4093-2 reached above endogenous control levels at 22 h in G. mellonella but not in M. sexta. Overall, pirAB plu4093-2 transcripts were not as highly expressed in M. sexta as in G. mellonella, from 15 to 22 h. This is the first study to directly compare pirAB plu4093-2 toxin transcript production considering different portals of entry.

  10. Identification of genes involved in the mutualistic colonization of the nematode Heterorhabditis bacteriophora by the bacterium Photorhabdus luminescens.

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    Easom, Catherine A

    2010-01-01

    ABSTRACT: BACKGROUND: Photorhabdus are Gram negative entomopathogenic bacteria that also have a mutualistic association with nematodes from the family Heterorhabditis. An essential part of this symbiosis is the ability of the bacterium to colonize the gut of the freeliving form of the nematode called the infective juvenile (IJ). Although the colonization process (also called transmission) has been described phenomonologically very little is known about the underlying molecular mechanisms. Therefore, in this study, we were interested in identifying genes in Photorhabdus that are important for IJ colonization. RESULTS: In this work we genetically tagged P. luminescens TT01 with gfp and constructed a library containing over 3200 mutants using the suicide vector, pUT-Km2. Using a combination of in vitro symbiosis assays and fluorescent microscopy we screened this library for mutants that were affected in their ability to colonize the IJ i.e. with decreased transmission frequencies. In total 8 mutants were identified with transmission frequencies of <\\/= 30% compared to wild-type. These mutants were mapped to 6 different genetic loci; the pbgPE operon, galE, galU, proQ, asmA and hdfR. The pbgPE, galE and galU mutants were all predicted to be involved in LPS biosynthesis and, in support of this, we have shown that these mutants are avirulent and sensitive to the cationic antimicriobial peptide, polymyxin B. On the other hand the proQ, asmA and hdfR mutants were not affected in virulence and were either as resistant (proQ) or slightly more sensitive (asmA, hdfR) to polymyxin B than the wild-type (WT). CONCLUSIONS: This is the first report describing the outcome of a comprehensive screen looking for transmission mutants in Photorhabdus. In total 6 genetic loci were identified and we present evidence that all of these loci are involved in the assembly and\\/or maintenance of LPS and other factors associated with the cell surface. Interestingly several, but not all, of the

  11. The occurrence of Photorhabdus-like toxin complexes in Bacillus thuringiensis

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    Recently, genomic sequencing of a Bacillus thuringiensis (Bt) isolate from our collection revealed the presence of an apparent operon encoding an insecticidal toxin complex (Tca) similar to that first described from the entomopathogen Photorhabdus luminescens. To determine whether these genes are w...

  12. The role of iron uptake in pathogenicity and symbiosis in Photorhabdus luminescens TT01

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    Joyce Susan A

    2010-06-01

    Full Text Available Abstract Background Photorhabdus are Gram negative bacteria that are pathogenic to insect larvae whilst also having a mutualistic interaction with nematodes from the family Heterorhabditis. Iron is an essential nutrient and bacteria have different mechanisms for obtaining both the ferrous (Fe2+ and ferric (Fe3+ forms of this metal from their environments. In this study we were interested in analyzing the role of Fe3+ and Fe2+ iron uptake systems in the ability of Photorhabdus to interact with its invertebrate hosts. Results We constructed targeted deletion mutants of exbD, feoABC and yfeABCD in P. luminescens TT01. The exbD mutant was predicted to be crippled in its ability to obtain Fe3+ and we show that this mutant does not grow well in iron-limited media. We also show that this mutant was avirulent to the insect but was unaffected in its symbiotic interaction with Heterorhabditis. Furthermore we show that a mutation in feoABC (encoding a predicted Fe2+ permease was unaffected in both virulence and symbiosis whilst the divalent cation transporter encoded by yfeABCD is required for virulence in the Tobacco Hornworm, Manduca sexta (Lepidoptera but not in the Greater Wax Moth, Galleria mellonella (Lepidoptera. Moreover the Yfe transporter also appears to have a role during colonization of the IJ stage of the nematode. Conclusion In this study we show that iron uptake (via the TonB complex and the Yfe transporter is important for the virulence of P. luminescens to insect larvae. Moreover this study also reveals that the Yfe transporter appears to be involved in Mn2+-uptake during growth in the gut lumen of the IJ nematode. Therefore, the Yfe transporter in P. luminescens TT01 is important during colonization of both the insect and nematode and, moreover, the metal ion transported by this pathway is host-dependent.

  13. Yersinia enterocolitica and Photorhabdus asymbiotica β-lactamases BlaA are exported by the twin-arginine translocation pathway.

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    Schriefer, Eva-Maria; Hoffmann-Thoms, Stephanie; Schmid, Franz X; Schmid, Annika; Heesemann, Jürgen

    2013-01-01

    In general, β-lactamases of medically important Gram-negative bacteria are Sec-dependently translocated into the periplasm. In contrast, β-lactamases of Mycobacteria spp. (BlaC, BlaS) and the Gram-negative environmental bacteria Stenotrophomonas maltophilia (L2) and Xanthomonas campestris (Bla(XCC-1)) have been reported to be secreted by the twin-arginine translocation (Tat) system. Yersinia enterocolitica carries 2 distinct β-lactamase genes (blaA and blaB) encoding BlaA(Ye) and the AmpC-like β-lactamase BlaB, respectively. By using the software PRED-TAT for prediction and discrimination of Sec from Tat signal peptides, we identified a functional Tat signal sequence for Yersinia BlaA(Ye). The Tat-dependent translocation of BlaA(Ye) could be clearly demonstrated by using a Y. enterocolitica tatC-mutant and cell fractionation. Moreover, we could demonstrate a unique unusual temperature-dependent activity profile of BlaA(Ye) ranging from 15 to 60 °C and a high 'melting temperature' (T(M)=44.3°) in comparison to the related Sec-dependent β-lactamase TEM-1 (20-50°C, T(M)=34.9 °C). Strikingly, the blaA gene of Y. enterocolitica is present in diverse environmental Yersinia spp. and a blaA homolog gene could be identified in the closely related Photorhabdus asymbiotica (BlaA(Pa); 69% identity to BlaA(Ye)). For BlaA(Pa) of P. asymbiotica, we could also demonstrate Tat-dependent secretion. These results suggest that Yersinia BlaA-related β-lactamases may be the prototype of a large Tat-dependent β-lactamase family, which originated from environmental bacteria. Copyright © 2012 Elsevier GmbH. All rights reserved.

  14. Common Virulence Factors and Tissue Targets of Entomopathogenic Bacteria for Biological Control of Lepidopteran Pests

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    Anaïs Castagnola

    2014-01-01

    Full Text Available This review focuses on common insecticidal virulence factors from entomopathogenic bacteria with special emphasis on two insect pathogenic bacteria Photorhabdus (Proteobacteria: Enterobacteriaceae and Bacillus (Firmicutes: Bacillaceae. Insect pathogenic bacteria of diverse taxonomic groups and phylogenetic origin have been shown to have striking similarities in the virulence factors they produce. It has been suggested that the detection of phage elements surrounding toxin genes, horizontal and lateral gene transfer events, and plasmid shuffling occurrences may be some of the reasons that virulence factor genes have so many analogs throughout the bacterial kingdom. Comparison of virulence factors of Photorhabdus, and Bacillus, two bacteria with dissimilar life styles opens the possibility of re-examining newly discovered toxins for novel tissue targets. For example, nematodes residing in the hemolymph may release bacteria with virulence factors targeting neurons or neuromuscular junctions. The first section of this review focuses on toxins and their context in agriculture. The second describes the mode of action of toxins from common entomopathogens and the third draws comparisons between Gram positive and Gram negative bacteria. The fourth section reviews the implications of the nervous system in biocontrol.

  15. Genetic and proteomic characterization of rpoB mutations and their effect on nematicidal activity in Photorhabdus luminescens LN2.

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    Xuehong Qiu

    Full Text Available Rifampin resistant (Rif(R mutants of the insect pathogenic bacterium Photorhabdus luminescens LN2 from entomopathogenic nematode Heterorhabditis indica LN2 were genetically and proteomically characterized. The Rif(R mutants showed typical phase one characters of Photorhabdus bacteria, and insecticidal activity against Galleria mellonella larvae, but surprisingly influenced their nematicidal activity against axenic infective juveniles (IJs of H. bacteriophora H06, an incompatible nematode host. 13 out of 34 Rif(R mutants lost their nematicidal activity against H06 IJs but supported the reproduction of H06 nematodes. 7 nematicidal-producing and 7 non-nematicidal-producing Rif(R mutants were respectively selected for rpoB sequence analysis. rpoB mutations were found in all 14 Rif(R mutants. The rpoB (P564L mutation was found in all 7 mutants which produced nematicidal activity against H06 nematodes, but not in the mutants which supported H06 nematode production. Allelic exchange assays confirmed that the Rif-resistance and the impact on nematicidal activity of LN2 bacteria were conferred by rpoB mutation(s. The non-nematicidal-producing Rif(R mutant was unable to colonize in the intestines of H06 IJs, but able to colonize in the intestines of its indigenous LN2 IJs. Proteomic analysis revealed different protein expression between wild-type strain and Rif(R mutants, or between nematicidal-producing and non nematicidal-producing mutants. At least 7 putative proteins including DsbA, HlpA, RhlE, RplC, NamB (a protein from T3SS, and 2 hypothetical proteins (similar to unknown protein YgdH and YggE of Escherichia coli respectively were probably involved in the nematicidal activity of LN2 bacteria against H06 nematodes. This hypothesis was further confirmed by creating insertion-deletion mutants of three selected corresponding genes (the downregulated rhlE and namB, and upregulated dsbA. These results indicate that the rpoB mutations greatly influence the

  16. Evolutionary patchwork of an insecticidal toxin shared between plant-associated pseudomonads and the insect pathogens Photorhabdus and Xenorhabdus.

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    Ruffner, Beat; Péchy-Tarr, Maria; Höfte, Monica; Bloemberg, Guido; Grunder, Jürg; Keel, Christoph; Maurhofer, Monika

    2015-08-16

    Root-colonizing fluorescent pseudomonads are known for their excellent abilities to protect plants against soil-borne fungal pathogens. Some of these bacteria produce an insecticidal toxin (Fit) suggesting that they may exploit insect hosts as a secondary niche. However, the ecological relevance of insect toxicity and the mechanisms driving the evolution of toxin production remain puzzling. Screening a large collection of plant-associated pseudomonads for insecticidal activity and presence of the Fit toxin revealed that Fit is highly indicative of insecticidal activity and predicts that Pseudomonas protegens and P. chlororaphis are exclusive Fit producers. A comparative evolutionary analysis of Fit toxin-producing Pseudomonas including the insect-pathogenic bacteria Photorhabdus and Xenorhadus, which produce the Fit related Mcf toxin, showed that fit genes are part of a dynamic genomic region with substantial presence/absence polymorphism and local variation in GC base composition. The patchy distribution and phylogenetic incongruence of fit genes indicate that the Fit cluster evolved via horizontal transfer, followed by functional integration of vertically transmitted genes, generating a unique Pseudomonas-specific insect toxin cluster. Our findings suggest that multiple independent evolutionary events led to formation of at least three versions of the Mcf/Fit toxin highlighting the dynamic nature of insect toxin evolution.

  17. Suppressive effects of metabolites from Photorhabdus spp. and Xenorhabdus spp. on phytopathogens of peach and pecan

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    Our objective was to determine the suppressive abilities of bacterial metabolites derived from Photorhabdus and Xenorhabdus spp. on Glomerella cingulata, Phomopsis sp., Phytophthora cactorum, and Fusicladosporium effusum, which are fungal or oomycete pathogens of pecan, and Monilinia fructicola, a f...

  18. The influence of Photorhabdus luminescens strains and form variants on the reproduction and bacterial retention of Heterorhabditis megidis

    NARCIS (Netherlands)

    Gerritsen, L.J.M.; Smits, P.H.

    1997-01-01

    The preference of nematodes for feeding on, and retention of strains and form variants of symbionts was tested. Heterorhabditis megidis strains DH-SH1 (= HSH) and NLH-E87.3 (= HE) could multiply on the primary forms of both symbionts. Photorhabdus luminescens strains PSH/1 and PE/1, respectively,

  19. Next-generation sequencing-based transcriptome analysis of Helicoverpa armigera Larvae immune-primed with Photorhabdus luminescens TT01.

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    Zengyang Zhao

    Full Text Available Although invertebrates are incapable of adaptive immunity, immunal reactions which are functionally similar to the adaptive immunity of vertebrates have been described in many studies of invertebrates including insects. The phenomenon was termed immune priming. In order to understand the molecular mechanism of immune priming, we employed Illumina/Solexa platform to investigate the transcriptional changes of the hemocytes and fat body of Helicoverpa armigera larvae immune-primed with the pathogenic bacteria Photorhabdus luminescens TT01. A total of 43.6 and 65.1 million clean reads with 4.4 and 6.5 gigabase sequence data were obtained from the TT01 (the immune-primed and PBS (non-primed cDNA libraries and assembled into 35,707 all-unigenes (non-redundant transcripts, which has a length varied from 201 to 16,947 bp and a N50 length of 1,997 bp. For 35,707 all-unigenes, 20,438 were functionally annotated and 2,494 were differentially expressed after immune priming. The differentially expressed genes (DEGs are mainly related to immunity, detoxification, development and metabolism of the host insect. Analysis on the annotated immune related DEGs supported a hypothesis that we proposed previously: the immune priming phenomenon observed in H. armigera larvae was achieved by regulation of key innate immune elements. The transcriptome profiling data sets (especially the sequences of 1,022 unannotated DEGs and the clues (such as those on immune-related signal and regulatory pathways obtained from this study will facilitate immune-related novel gene discovery and provide valuable information for further exploring the molecular mechanism of immune priming of invertebrates. All these will increase our understanding of invertebrate immunity which may provide new approaches to control insect pests or prevent epidemic of infectious diseases in economic invertebrates in the future.

  20. Comparative analysis of the Photorhabdus luminescens and the Yersinia enterocolitica genomes: uncovering candidate genes involved in insect pathogenicity

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    Fuchs Thilo M

    2008-01-01

    Full Text Available Abstract Background Photorhabdus luminescens and Yersinia enterocolitica are both enteric bacteria which are associated with insects. P. luminescens lives in symbiosis with soil nematodes and is highly pathogenic towards insects but not to humans. In contrast, Y. enterocolitica is widely found in the environment and mainly known to cause gastroenteritis in men, but has only recently been shown to be also toxic for insects. It is expected that both pathogens share an overlap of genetic determinants that play a role within the insect host. Results A selective genome comparison was applied. Proteins belonging to the class of two-component regulatory systems, quorum sensing, universal stress proteins, and c-di-GMP signalling have been analysed. The interorganismic synopsis of selected regulatory systems uncovered common and distinct signalling mechanisms of both pathogens used for perception of signals within the insect host. Particularly, a new class of LuxR-like regulators was identified, which might be involved in detecting insect-specific molecules. In addition, the genetic overlap unravelled a two-component system that is unique for the genera Photorhabdus and Yersinia and is therefore suggested to play a major role in the pathogen-insect relationship. Our analysis also highlights factors of both pathogens that are expressed at low temperatures as encountered in insects in contrast to higher (body temperature, providing evidence that temperature is a yet under-investigated environmental signal for bacterial adaptation to various hosts. Common degradative metabolic pathways are described that might be used to explore nutrients within the insect gut or hemolymph, thus enabling the proliferation of P. luminescens and Y. enterocolitica in their invertebrate hosts. A strikingly higher number of genes encoding insecticidal toxins and other virulence factors in P. luminescens compared to Y. enterocolitica correlates with the higher virulence of P

  1. High-level expression, purification and antibacterial activity of bovine lactoferricin and lactoferrampin in Photorhabdus luminescens.

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    Tang, Zhiru; Zhang, Youming; Stewart, Adrian Francis; Geng, Meimei; Tang, Xiangsha; Tu, Qiang; Yin, Yulong

    2010-10-01

    Bovine lactoferricin (LFC) and bovine lactoferrampin (LFA) are two active fragments located in the N(1)-domain of bovine lactoferrin. Recent studies suggested that LFC and LFA have broad-spectrum activity against Gram-positive and Gram-negative bacteria. To date, LFC and LFA have usually been produced from milk. We report here the high-level expression, purification and characterization of LFC and LFA using the Photorhabdus luminescens expression system. After the cipA and cipB genes were deleted by ET recombination, the expression host P. luminescens TZR(001) was constructed. A synthetic LFC-LFA gene containing LFC and LFA was fused with the cipB gene to form a cipB-LFC-LFA gene. To obtain the expression vector pBAD-cipB-LFC-LFA, the cipB-LFC-LFA gene was cloned on the L-arabinose-inducible expression vector pBAD24. pBAD-cipB-LFC-LFA was transformed into P. luminescens TZR(001). The cipB-LFC-LFA fusion protein was expressed under the induction of L-arabinose and its yield reached 12 mg L(-1) bacterial culture. Recombinant LFC-LFA was released from cipB by pepsin. The MIC of recombinant LFC-LFA toward E. coli 0149, 0141 and 020 was 6.25, 12.5 and 3.175 microg ml(-1), respectively. Copyright 2010 Elsevier Inc. All rights reserved.

  2. Photorhabdus luminescens genes induced upon insect infection

    Directory of Open Access Journals (Sweden)

    Jung Kirsten

    2008-05-01

    Full Text Available Abstract Background Photorhabdus luminescens is a Gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species Heterorhabditis bacteriophora. P.luminescens is simultaneously highly pathogenic to insects. This bacterium exhibits a complex life cycle, including one symbiotic stage characterized by colonization of the upper nematode gut, and a pathogenic stage, characterized by release from the nematode into the hemocoel of insect larvae, resulting in rapid insect death caused by bacterial toxins. P. luminescens appears to sense and adapt to the novel host environment upon changing hosts, which facilitates the production of factors involved in survival within the host, host-killing, and -exploitation. Results A differential fluorescence induction (DFI approach was applied to identify genes that are up-regulated in the bacterium after infection of the insect host Galleria mellonella. For this purpose, a P. luminescens promoter-trap library utilizing the mCherry fluorophore as a reporter was constructed, and approximately 13,000 clones were screened for fluorescence induction in the presence of a G. mellonella larvae homogenate. Since P. luminescens has a variety of regulators that potentially sense chemical molecules, like hormones, the screen for up-regulated genes or operons was performed in vitro, excluding physicochemical signals like oxygen, temperature or osmolarity as variables. Clones (18 were obtained exhibiting at least 2.5-fold induced fluorescence and regarded as specific responders to insect homogenate. In combination with a bioinformatics approach, sequence motifs were identified in these DNA-fragments that are similar to 29 different promoters within the P. luminescens genome. By cloning each of the predicted promoters upstream of the reporter gene, induction was verified for 27 promoters in vitro, and for 24 promoters in viable G. mellonella larvae. Among the validated promoters are some known

  3. Effects of co-occurring Wolbachia and Spiroplasma endosymbionts on the Drosophila immune response against insect pathogenic and non-pathogenic bacteria.

    Science.gov (United States)

    Shokal, Upasana; Yadav, Shruti; Atri, Jaishri; Accetta, Julia; Kenney, Eric; Banks, Katherine; Katakam, Akash; Jaenike, John; Eleftherianos, Ioannis

    2016-02-09

    Symbiotic interactions between microbes and animals are common in nature. Symbiotic organisms are particularly common in insects and, in some cases, they may protect their hosts from pathogenic infections. Wolbachia and Spiroplasma endosymbionts naturally inhabit various insects including Drosophila melanogaster fruit flies. Therefore, this symbiotic association is considered an excellent model to investigate whether endosymbiotic bacteria participate in host immune processes against certain pathogens. Here we have investigated whether the presence of Wolbachia alone or together with Spiroplasma endosymbionts in D. melanogaster adult flies affects the immune response against the virulent insect pathogen Photorhabdus luminescens and against non-pathogenic Escherichia coli bacteria. We found that D. melanogaster flies carrying no endosymbionts, those carrying both Wolbachia and Spiroplasma, and those containing Wolbachia only had similar survival rates after infection with P. luminescens or Escherichia coli bacteria. However, flies carrying both endosymbionts or Wolbachia only contained higher numbers of E. coli cells at early time-points post infection than flies without endosymbiotic bacteria. Interestingly, flies containing Wolbachia only had lower titers of this endosymbiont upon infection with the pathogen P. luminescens than uninfected flies of the same strain. We further found that the presence of Wolbachia and Spiroplasma in D. melanogaster up-regulated certain immune-related genes upon infection with P. luminescens or E. coli bacteria, but it failed to alter the phagocytic ability of the flies toward E. coli inactive bioparticles. Our results suggest that the presence of Wolbachia and Spiroplasma in D. melanogaster can modulate immune signaling against infection by certain insect pathogenic and non-pathogenic bacteria. Results from such studies are important for understanding the molecular basis of the interactions between endosymbiotic bacteria of insects

  4. The broadly insecticidal Photorhabdus luminescens toxin complex a (Tca): Activity against the Colorado potato beetle, Leptinotarsa decemlineata, and sweet potato whitefly, Bemisia tabaci

    OpenAIRE

    Blackburn, Michael B.; Domek, John M.; Gelman, Dale B.; Hu, Jing S.

    2005-01-01

    Toxin complex a (Tca), a high molecular weight insecticidal protein complex produced by the entomopathogenic bacterium Photorhabdus luminescens, has been found to be orally toxic to both the Colorado potato beetle, Leptinotarsa decemlineata, and the sweet potato whitefly, Bemisia tabaci biotype B. The 48 hour LC50 for Tca against neonate L. decemlineata was found to be 2.7 ppm, and the growth of 2nd instar L. decemlineata exposed to Tca for 72 hours was almost entirely inhibited at concentrat...

  5. Identification of entomopathogenic nematodes and symbiotic bacteria from Nam Nao National Park in Thailand and larvicidal activity of symbiotic bacteria against Aedes aegypti and Aedes albopictus.

    Science.gov (United States)

    Yooyangket, Temsiri; Muangpat, Paramaporn; Polseela, Raxsina; Tandhavanant, Sarunporn; Thanwisai, Aunchalee; Vitta, Apichat

    2018-01-01

    Entomopathogenic nematodes (EPNs) that are symbiotically associated with Xenorhabdus and Photorhabdus bacteria can kill target insects via direct infection and toxin action. There are limited reports identifying such organisms in the National Park of Thailand. Therefore, the objectives of this study were to identify EPNs and symbiotic bacteria from Nam Nao National Park, Phetchabun Province, Thailand and to evaluate the larvicidal activity of bacteria against Aedes aegypti and Ae. albopictus. A total of 12 EPN isolates belonging to Steinernema and Heterorhabditis were obtained form 940 soil samples between February 2014 and July 2016. EPNs were molecularly identified as S. websteri (10 isolates) and H. baujardi (2 isolates). Symbiotic bacteria were isolated from EPNs and molecularly identified as P. luminescens subsp. akhurstii (13 isolates), X. stockiae (11 isolates), X. vietnamensis (2 isolates) and X. japonica (1 isolate). For the bioassay, bacterial suspensions were evaluated for toxicity against third to early fourth instar larvae of Aedes spp. The larvae of both Aedes species were orally susceptible to symbiotic bacteria. The highest larval mortality of Ae. aegypti was 99% after exposure to X. stockiae (bNN112.3_TH) at 96 h, and the highest mortality of Ae. albopictus was 98% after exposure to P. luminescens subsp. akhurstii (bNN121.4_TH) at 96 h. In contrast to the control groups (Escherichia coli and distilled water), the mortality rate of both mosquito larvae ranged between 0 and 7% at 72 h. Here, we report the first observation of X. vietnamensis in Thailand. Additionally, we report the first observation of P. luminescens subsp. akhurstii associated with H. baujardi in Thailand. X. stockiae has potential to be a biocontrol agent for mosquitoes. This investigation provides a survey of the basic diversity of EPNs and symbiotic bacteria in the National Park of Thailand, and it is a bacterial resource for further studies of bioactive compounds.

  6. Photorhabdus insect-related (Pir) toxin-like genes in a plasmid of Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND) of shrimp

    Science.gov (United States)

    Han, Jee Eun; Tang, Kathy F. J.; Tran, Loc H.; Lightner, Donald V.

    2016-01-01

    The 69 kb plasmid pVPA3-1 was identified in Vibrio parahaemolyticus strain 13-028/A3 that can cause acute hepatopancreatic necrosis disease (AHPND). This disease is responsible for mass mortalities in farmed penaeid shrimp and is referred to as early mortality syndrome (EMS). The plasmid has a GC content of 45.9% with a copy number of 37 per bacterial cell as determined by comparative quantitative PCR analyses. It consists of 92 open reading frames that encode mobilization proteins, replication enzymes, transposases, virulence-associated proteins, and proteins similar to Photorhabdus insect-related (Pir) toxins. In V. parahaemolyticus, these Pir toxin-like proteins are encoded by 2 genes ( pirA- and pirB-like) located within a 3.5 kb fragment flanked with inverted repeats of a transposase-coding sequence (1 kb). The GC content of these 2 genes is only 38.2%, substantially lower than that of the rest of the plasmid, which suggests that these genes were recently acquired. Based on a proteomic analysis, the pirA-like (336 bp) and pirB-like (1317 bp) genes encode for 13 and 50 kDa proteins, respectively. In laboratory cultures of V. parahaemolyticus 13-028/A3, both proteins were secreted into the culture medium. We developed a duplex PCR diagnostic method, with a detection limit of 105 CFU ml−1 and targeting pirA- and pirB-like genes in this strain of V. parahaemolyticus. This PCR protocol can reliably detect AHPND-causing strains of V. parahaemolyticus and does not cross react with non-pathogenic strains or with other species of Vibrio isolated from shrimp ponds. PMID:25667334

  7. BACTERIA CARRIED BY CHRYSOMYA MEGACEPHALA (FABRICIUS, 1794 (DIPTERA: CALLIPHORIDAE IN SINOP, MATO GROSSO, BRAZIL

    Directory of Open Access Journals (Sweden)

    J. S. Carneiro

    2014-07-01

    Full Text Available Chrysomya megacephala (Diptera: Calliphoridae, popularly known as blowfly, has a great capacity for dispersion and, due to factors such as food abundance and favorable climate, it colonizes Brazil completely in a short time. These insects are important to the sectors of epidemiology, public health and forensics, especially due to carrying microorganisms such as bacteria, viruses, protozoa and helminthes, which are responsible for the spread of diseases such as dysentery, cholera, botulism, typhoid fever, brucellosis, polio, smallpox and tuberculosis. The objective of this study was to verify the diversity of bacteria carried by this species in the Federal University of Mato Grosso – Campus of Sinop during the month of January of 2012. The flies were collected using two traps baited with 100 g of fresh sardines on each and maintained in the field for 24 hours. Twenty specimens of C. megacephala were placed in Petri dishes, to walk for two minutes upon Nutrient Agar (NA. After establishment of the colonies, isolation of the bacteria on the NA medium and their multiplication in test tubes containing the same culture medium was performed, and later sent to identification by gas chromatography. The bacteria encountered were Aquaspirillum polymorphum; Burkholderia ambifaria; Burkholderia anthina; Burkholderia cepacia; Burkholderia cenocepacia; Burkholderia pyrrocinia; Burkholderia stabilis; Paenibacillus macerans; Virgibacillus pantothenticus, Bacillus subtilis e Photorhabdus luminescens luminescens, with the last two species considered of importance in the plant protection sector.

  8. Structural comparison of contractile nanomachines

    Directory of Open Access Journals (Sweden)

    Sebastian Kube

    2015-05-01

    Full Text Available Contractile molecular machines are a common feature among bacteriophages and prokaryotes. Due to their stability and the large size, contractile-tailed bacteriophages are traditionally investigated by electron microscopic methods. Complemented by crystallographic studies, a molecular model of contraction for the T4 phage was developed. Lately, also related contractile structures like the Photorhabdus virulence cassette-like particles, the R-Type pyocins and the contractile tubule of the bacterial Type VI secretion system have been analyzed by cryo electron microscopy. Photorhabdus virulence cassette particles and R-Type pyocins are toxin complexes reminiscent of bacteriophage tails that are secreted by bacteria to kill their insect host or competing bacteria. In contrast, the Type VI secretion system is an intracellular apparatus for injection of effector proteins into bacterial and eukaryotic cells. Although it shares homology with other contractile systems, the Type VI secretion system is additionally equipped with a recycling function, which makes it suitable for multiple rounds of action. Starting from the 3D reconstructions, we compare these molecular machines structurally and functionally to their viral counterparts and summarize the current knowledge on their respective mode of action.

  9. Transformation of nitrogen and distribution of nitrogen-related bacteria in a polluted urban stream.

    Science.gov (United States)

    Jiao, Y; Jin, W B; Zhao, Q L; Zhang, G D; Yan, Y; Wan, J

    2009-01-01

    Most researchers focused on either nitrogen species or microbial community for polluted urban stream while ignoring the interaction between them and its effect on nitrogen transformation, which restricted the rational selection of an effective and feasible remediation technology. Taking Buji stream in Shenzhen (China) as target stream, the distribution of nitrogen-related bacteria was investigated by most probable number (MPN) besides analysis of nitrogen species etc. The nitrogen-related bacteria in sediment were 10(2) times richer than those in water. Owing to their faster growth, the MPN of ammonifying bacteria and denitrifying bacteria were 10(5) and 10(2) times higher than those of nitrifying bacteria, respectively. The ammonifying bacteria numbers were significantly related to BOD5 in water, while nitrifying bacteria in sediment correlated well with nitrate in water. Thus, nitrification occurred mainly in sediment surface and was limited by low proportion of nitrifying bacteria. The denitrifying bacteria in sediment had good relationship with BOD5 and nitrite and nitrate in water. Low DO and rich organic compounds were beneficial to denitrification but unfavourable to nitrification. Denitrification was restricted by low nitrite and nitrate concentration. These results could be served as a reference for implementing the remediation scheme of nitrogen polluted urban stream.

  10. 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.

  11. Relative feeding rates on free and particle-bound bacteria by freshwater macrozooplankton

    International Nuclear Information System (INIS)

    Schoenberg, S.A.; Maccubbin, A.E.

    1985-01-01

    Feeding suspensions of equivalent particle spectra were assembled with either free-living ( 3 H]thymidine. Clearance (ml ind -1 d -1 ) of attached bacteria was 3-29 x that of free bacteria for the cladocerans Acantholeberis, Chydorus, and Eubosmina. Pseudosida and Ceriodaphnia showed weaker discrimination or no selection, indicating a lower size threshold for filtration in these species. Feeding suspensions composed of isolated free bacteria yielded significantly higher or lower estimates of grazing than free bacteria with the full complement of particles, depending on species. Relative clearance (attached:free) tended to increase with body size within a species and varied for different particle environments. Bacteria associated with large particles may increase detrital energy flow to consumers in eutrophic environments

  12. Meconium microbiome analysis identifies bacteria correlated with premature birth.

    Directory of Open Access Journals (Sweden)

    Alexandria N Ardissone

    Full Text Available Preterm birth is the second leading cause of death in children under the age of five years worldwide, but the etiology of many cases remains enigmatic. The dogma that the fetus resides in a sterile environment is being challenged by recent findings and the question has arisen whether microbes that colonize the fetus may be related to preterm birth. It has been posited that meconium reflects the in-utero microbial environment. In this study, correlations between fetal intestinal bacteria from meconium and gestational age were examined in order to suggest underlying mechanisms that may contribute to preterm birth.Meconium from 52 infants ranging in gestational age from 23 to 41 weeks was collected, the DNA extracted, and 16S rRNA analysis performed. Resulting taxa of microbes were correlated to clinical variables and also compared to previous studies of amniotic fluid and other human microbiome niches.Increased detection of bacterial 16S rRNA in meconium of infants of <33 weeks gestational age was observed. Approximately 61·1% of reads sequenced were classified to genera that have been reported in amniotic fluid. Gestational age had the largest influence on microbial community structure (R = 0·161; p = 0·029, while mode of delivery (C-section versus vaginal delivery had an effect as well (R = 0·100; p = 0·044. Enterobacter, Enterococcus, Lactobacillus, Photorhabdus, and Tannerella, were negatively correlated with gestational age and have been reported to incite inflammatory responses, suggesting a causative role in premature birth.This provides the first evidence to support the hypothesis that the fetal intestinal microbiome derived from swallowed amniotic fluid may be involved in the inflammatory response that leads to premature birth.

  13. Frost related dieback in Estonian energy plantations of willows in relation to fertilisation and pathogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cambours, M.A.; Nejad, P. [Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, 750 07 Uppsala (Sweden); Heinsoo, K. [Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu (Estonia); Granhall, U. [Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala (Sweden)

    2006-03-15

    Two 9-year old Estonian Salix plantations suffering from dieback were studied: one situated on poor mineral soil and divided into fertilised and unfertilised plots (Saare plantation) and another growing on a well-decomposed and nitrogen-rich organic soil, without fertiliser application (Kambja plantation). Bacteria from internal tissues of visually damaged shoots from seven clones were isolated in spring and autumn. The strains were subsequently biochemically characterised and tested for ice nucleation activity and pathogenicity on Salix. Some strains were also analysed with 16S rRNA. High numbers of culturable bacteria were found, belonging mainly to Erwinia, Sphingomonas, Pseudomonas and Xanthomonas spp. Fertilised plots were significantly more colonised by bacteria than unfertilised plots and also more extensively damaged, showing a lower density of living plants after 7 years of culture. More ice nucleation active (INA) strains were found in Saare fertilised plots and at Kambja than in Saare unfertilised plots. Likewise, most pathogenic strains were isolated from Saare fertilised plots and from Kambja. For some of the willow clones studied, dieback appeared to be related to both clonal frost sensitivity and abundance of INA and pathogenic bacteria. The plantations probably suffered from the presence of high amounts of pathogens and from frost related injuries aggravated by INA bacteria. Most probably the fertilisation at Saare and the nitrogen-rich soil at Kambja created a favourable environment for bacterial development and led to high dieback levels after the first harvest. (author)

  14. An insect pathogenic symbiosis between a Caenorhabditis and Serratia

    Science.gov (United States)

    Morrison, Julie; Cooper, Vaughn; Thomas, W. Kelley

    2011-01-01

    We described an association between a strain of the nematode Caenorhabditis briggsae, i.e. KT0001, and the bacteria Serratia sp. SCBI (South African Caenorhabditis briggsae isolate), which was able to kill the insect Galleria (G. mellonella). Here we show that the Serratia sp. SCBI lines the gut of the nematode, similar to the Heterorhabditis-Photorhabdus complex, indicating that the association is possibly internal. We also expand on the relevance of this tripartite, i.e. insect-nematode-bacteria, interaction in the broader evolutionary context and Caenorhabditis natural history. PMID:21389770

  15. Enrichment of marine anammox bacteria from seawater-related samples and bacterial community study.

    Science.gov (United States)

    Kawagoshi, Y; Nakamura, Y; Kawashima, H; Fujisaki, K; Furukawa, K; Fujimoto, A

    2010-01-01

    Anaerobic ammonium oxidation (anammox) is a novel nitrogen pathway catalyzed by anammox bacteria which are obligate anaerobic chemoautotrophs. In this study, enrichment culture of marine anammox bacteria (MAAOB) from the samples related to seawater was conducted. Simultaneous removal of ammonium and nitrite was confirmed in continuous culture inoculated with sediment of a sea-based waste disposal site within 50 days. However, no simultaneous nitrogen removal was observed in cultures inoculated with seawater-acclimated denitrifying sludge or with muddy sediment of tideland even during 200 days. Nitrogen removal rate of 0.13 kg/m(3)/day was achieved at nitrogen loading rate of 0.16 kg/m(3)/day after 320th days in the culture inoculated with the sediment of waste disposal site. The nitrogen removal ratio between ammonium nitrogen and nitrite nitrogen was 1:1.07. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that an abundance of the bacteria close to MAAOB and coexistence of ammonium oxidizing bacteria and denitrifying bacteria in the culture.

  16. Cycle inhibiting factors (CIFs are a growing family of functional cyclomodulins present in invertebrate and mammal bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Grégory Jubelin

    Full Text Available The cycle inhibiting factor (Cif produced by enteropathogenic and enterohemorrhagic Escherichia coli was the first cyclomodulin to be identified that is injected into host cells via the type III secretion machinery. Cif provokes cytopathic effects characterized by G(1 and G(2 cell cycle arrests, accumulation of the cyclin-dependent kinase inhibitors (CKIs p21(waf1/cip1 and p27(kip1 and formation of actin stress fibres. The X-ray crystal structure of Cif revealed it to be a divergent member of a superfamily of enzymes including cysteine proteases and acetyltransferases that share a conserved catalytic triad. Here we report the discovery and characterization of four Cif homologs encoded by different pathogenic or symbiotic bacteria isolated from vertebrates or invertebrates. Cif homologs from the enterobacteria Yersinia pseudotuberculosis, Photorhabdus luminescens, Photorhabdus asymbiotica and the beta-proteobacterium Burkholderia pseudomallei all induce cytopathic effects identical to those observed with Cif from pathogenic E. coli. Although these Cif homologs are remarkably divergent in primary sequence, the catalytic triad is strictly conserved and was shown to be crucial for cell cycle arrest, cytoskeleton reorganization and CKIs accumulation. These results reveal that Cif proteins form a growing family of cyclomodulins in bacteria that interact with very distinct hosts including insects, nematodes and humans.

  17. Synergistic Antibacterial Effects of Chitosan-Caffeic Acid Conjugate against Antibiotic-Resistant Acne-Related Bacteria.

    Science.gov (United States)

    Kim, Ji-Hoon; Yu, Daeung; Eom, Sung-Hwan; Kim, Song-Hee; Oh, Junghwan; Jung, Won-Kyo; Kim, Young-Mog

    2017-06-08

    The object of this study was to discover an alternative therapeutic agent with fewer side effects against acne vulgaris, one of the most common skin diseases. Acne vulgaris is often associated with acne-related bacteria such as Propionibacterium acnes , Staphylococcus epidermidis , Staphylococcus aureus , and Pseudomonas aeruginosa . Some of these bacteria exhibit a resistance against commercial antibiotics that have been used in the treatment of acne vulgaris (tetracycline, erythromycin, and lincomycin). In the current study, we tested in vitro antibacterial effect of chitosan-phytochemical conjugates on acne-related bacteria. Three chitosan-phytochemical conjugates used in this study exhibited stronger antibacterial activity than that of chitosan (unmodified control). Chitosan-caffeic acid conjugate (CCA) showed the highest antibacterial effect on acne-related bacteria along with minimum inhibitory concentration (MIC; 8 to 256 μg/mL). Additionally, the MIC values of antibiotics against antibiotic-resistant P. acnes and P. aeruginosa strains were dramatically reduced in combination with CCA, suggesting that CCA would restore the antibacterial activity of the antibiotics. The analysis of fractional inhibitory concentration (FIC) indices clearly revealed a synergistic antibacterial effect of CCA with antibiotics. Thus, the median sum of FIC (∑FIC) values against the antibiotic-resistant bacterial strains ranged from 0.375 to 0.533 in the combination mode of CCA and antibiotics. The results of the present study suggested a potential possibility of chitosan-phytochemical conjugates in the control of infections related to acne vulgaris.

  18. Emerging principles of inorganic nitrogen metabolism in Paracoccus denitrificans and related bacteria

    NARCIS (Netherlands)

    Stouthamer, A.H.; de Boer, A P; van der Oost, J.; van Spanning, R J

    The taxonomy of Paracoccus denitrificans and related bacteria is discussed. Evidence is given which shows that the physiological differences between P. denitrificans and Thiosphaera pantotropha are less fundamental than previously thought. A proposal to consider a species P. pantotropha is

  19. Relation between chemotaxis and consumption of amino acids in bacteria

    Science.gov (United States)

    Yang, Yiling; M. Pollard, Abiola; Höfler, Carolin; Poschet, Gernot; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    Summary Chemotaxis enables bacteria to navigate chemical gradients in their environment, accumulating toward high concentrations of attractants and avoiding high concentrations of repellents. Although finding nutrients is likely to be an important function of bacterial chemotaxis, not all characterized attractants are nutrients. Moreover, even for potential nutrients, the exact relation between the metabolic value of chemicals and their efficiency as chemoattractants has not been systematically explored. Here we compare the chemotactic response of amino acids with their use by bacteria for two well‐established models of chemotactic behavior, E scherichia coli and B acillus subtilis. We demonstrate that in E . coli chemotaxis toward amino acids indeed strongly correlates with their utilization. However, no such correlation is observed for B . subtilis, suggesting that in this case, the amino acids are not followed because of their nutritional value but rather as environmental cues. PMID:25807888

  20. Time related total lactic acid bacteria population diversity and ...

    African Journals Online (AJOL)

    user

    2011-02-07

    Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

  1. Identification and Characterization of the Insecticidal Toxin “Makes Caterpillars Floppy” in Photorhabdus temperata M1021 Using a Cosmid Library

    Directory of Open Access Journals (Sweden)

    Ihsan Ullah

    2014-07-01

    Full Text Available Photorhabdus temperata is an entomopathogenic enterobacterium; it is a nematode symbiont that possesses pathogenicity islands involved in insect virulence. Herein, we constructed a P. temperata M1021 cosmid library in Escherichia coli XL1-Blue MRF` and obtained 7.14 × 105 clones. However, only 1020 physiologically active clones were screened for insect virulence factors by injection of each E. coli cosmid clone into Galleria mellonella and Tenebrio molitor larvae. A single cosmid clone, PtC1015, was consequently selected due to its characteristic virulent properties, e.g., loss of body turgor followed by death of larvae when the clone was injected into the hemocoel. The sequence alignment against the available sequences in Swiss-Prot and NCBI databases, confirmed the presence of the mcf gene homolog in the genome of P. temperata M1021 showing 85% homology and 98% query coverage with the P. luminescens counterpart. Furthermore, a 2932 amino acid long Mcf protein revealed limited similarity with three protein domains. The N-terminus of the Mcf encompassed consensus sequence for a BH3 domain, the central region revealed similarity to toxin B, and the C-terminus of Mcf revealed similarity to the bacterial export domain of ApxIVA, an RTX-like toxin. In short, the Mcf toxin is likely to play a role in the elimination of insect pests, making it a promising model for use in the agricultural field.

  2. Identification and Characterization of the Insecticidal Toxin “Makes Caterpillars Floppy” in Photorhabdus temperata M1021 Using a Cosmid Library

    Science.gov (United States)

    Ullah, Ihsan; Jang, Eun-Kyung; Kim, Min-Sung; Shin, Jin-Ho; Park, Gun-Seok; Khan, Abdur Rahim; Hong, Sung-Jun; Jung, Byung-Kwon; Choi, JungBae; Park, YeongJun; Kwak, Yunyoung; Shin, Jae-Ho

    2014-01-01

    Photorhabdus temperata is an entomopathogenic enterobacterium; it is a nematode symbiont that possesses pathogenicity islands involved in insect virulence. Herein, we constructed a P. temperata M1021 cosmid library in Escherichia coli XL1-Blue MRF` and obtained 7.14 × 105 clones. However, only 1020 physiologically active clones were screened for insect virulence factors by injection of each E. coli cosmid clone into Galleria mellonella and Tenebrio molitor larvae. A single cosmid clone, PtC1015, was consequently selected due to its characteristic virulent properties, e.g., loss of body turgor followed by death of larvae when the clone was injected into the hemocoel. The sequence alignment against the available sequences in Swiss-Prot and NCBI databases, confirmed the presence of the mcf gene homolog in the genome of P. temperata M1021 showing 85% homology and 98% query coverage with the P. luminescens counterpart. Furthermore, a 2932 amino acid long Mcf protein revealed limited similarity with three protein domains. The N-terminus of the Mcf encompassed consensus sequence for a BH3 domain, the central region revealed similarity to toxin B, and the C-terminus of Mcf revealed similarity to the bacterial export domain of ApxIVA, an RTX-like toxin. In short, the Mcf toxin is likely to play a role in the elimination of insect pests, making it a promising model for use in the agricultural field. PMID:25014195

  3. Evaluation of entomopathogenic nematodes and the supernatants of the in vitro culture medium of their mutualistic bacteria for the control of the root-knot nematodes Meloidogyne incognita and M. arenaria.

    Science.gov (United States)

    Kepenekci, Ilker; Hazir, Selcuk; Lewis, Edwin E

    2016-02-01

    The suppressive effects of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their mutualistic bacteria on the root-knot nematodes (RKNs) Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. The aqueous suspensions of IJs, infected cadaver applications of EPNs and especially treatments of X. bovienii supernatant suppressed the negative impact of RKNs on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height and increased fresh and dry weights compared with the control where only RKNs were applied. Among the treatments tested, the plant-dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control. © 2015 Society of Chemical Industry.

  4. Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation.

    Science.gov (United States)

    García-Gil, Alejandro; Gasco-Cavero, Samanta; Garrido, Eduardo; Mejías, Miguel; Epting, Jannis; Navarro-Elipe, Mercedes; Alejandre, Carmen; Sevilla-Alcaine, Elena

    2018-08-15

    The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

    Science.gov (United States)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  6. Horse species symposium: a novel approach to monitoring pathogen progression during uterine and placental infection in the mare using bioluminescence imaging technology and lux-modified bacteria.

    Science.gov (United States)

    Ryan, P L; Christiansen, D L; Hopper, R M; Walters, F K; Moulton, K; Curbelo, J; Greene, J M; Willard, S T

    2011-05-01

    Uterine and placental infections are the leading cause of abortion, stillbirth, and preterm delivery in the mare. Whereas uterine and placental infections in women have been studied extensively, a comprehensive examination of the pathogenic processes leading to this unsatisfactory pregnancy outcome in the mare has yet to be completed. Most information in the literature relating to late-term pregnancy loss in mares is based on retrospective studies of clinical cases submitted for necropsy. Here we report the development and application of a novel approach, whereby transgenically modified bacteria transformed with lux genes of Xenorhabdus luminescens or Photorhabdus luminescens origin and biophotonic imaging are utilized to better understand pathogen-induced preterm birth in late-term pregnant mares. This technology uses highly sensitive bioluminescence imaging camera systems to localize and monitor pathogen progression during tissue invasion by measuring the bioluminescent signatures emitted by the lux-modified pathogens. This method has an important advantage in that it allows for the potential tracking of pathogens in vivo in real time and over time, which was hitherto impossible. Although the application of this technology in domestic animals is in its infancy, investigators were successful in identifying the fetal lungs, sinuses, nares, urinary, and gastrointestinal systems as primary tissues for pathogen invasion after experimental infection of pregnant mares with lux-modified Escherichia coli. It is important that pathogens were not detected in other vital organs, such as the liver, brain, and cardiac system. Such precision in localizing sites of pathogen invasion provides potential application for this novel approach in the development of more targeted therapeutic interventions for pathogen-related diseases in the equine and other domestic species.

  7. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  8. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  9. Effect of incubation temperatures for inactivation of Escherichia coli and related bacteria after gamma-irradiation

    International Nuclear Information System (INIS)

    Nakauma, Makoto; Ito, Hitoshi; Tada, Mikiro

    2000-01-01

    Irradiated fresh meat or fishery products have been expected to store and distribute under refrigerated temperature below 10degC. From previous reports, growth of coliform bacteria in these products were suppressed by gamma-irradiation below expected doses obtained at 30-37degC. This research was performed to observe the irradiation effect on the inactivation of Escherichia coli and related bacteria at different incubation temperatures of 10-40degC on plate agar after irradiation. From this study, D10 values of all strains decreased 17- 45% at 10degC compared with maximum D10 values at 30- 40degC. Radiation sensitivities were related to the ability to grow at low temperatures in which psychrotrophic type E. coli A4-1 indicated most sensitive to radiation, next of Salmonella enteritidis YK-2, E. coli S2, B4 whereas most resistant at Enterobacter agglomerans K3-1. (author)

  10. Effect of incubation temperatures for inactivation of Escherichia coli and related bacteria after gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakauma, Makoto; Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Tada, Mikiro [Okayama Univ. (Japan). Faculty of Agriculture

    2000-09-01

    Irradiated fresh meat or fishery products have been expected to store and distribute under refrigerated temperature below 10degC. From previous reports, growth of coliform bacteria in these products were suppressed by gamma-irradiation below expected doses obtained at 30-37degC. This research was performed to observe the irradiation effect on the inactivation of Escherichia coli and related bacteria at different incubation temperatures of 10-40degC on plate agar after irradiation. From this study, D10 values of all strains decreased 17- 45% at 10degC compared with maximum D10 values at 30- 40degC. Radiation sensitivities were related to the ability to grow at low temperatures in which psychrotrophic type E. coli A4-1 indicated most sensitive to radiation, next of Salmonella enteritidis YK-2, E. coli S2, B4 whereas most resistant at Enterobacter agglomerans K3-1. (author)

  11. Differential Change Patterns of Main Antimicrobial Peptide Genes During Infection of Entomopathogenic Nematodes and Their Symbiotic Bacteria.

    Science.gov (United States)

    Darsouei, Reyhaneh; Karimi, Javad; Ghadamyari, Mohammad; Hosseini, Mojtaba

    2017-08-01

    The expression of antimicrobial peptides (AMPs) as the main humoral defense reactions of insects during infection by entomopathogenic nematodes (EPNs) and their symbiont is addressed herein. Three AMPs, attacin, cecropin, and spodoptericin, were evaluated in the fifth instar larvae of Spodoptera exigua Hübner (beet armyworm) when challenged with Steinernema carpocapsae or Heterorhabditis bacteriophora. The results indicated that attacin was expressed to a greater extent than either cecropin or spodoptericin. While spodoptericin was expressed to a much lesser extent, this AMP was induced against Gram-positive bacteria, and thus not expressed after penetration of Xenorhabdus nematophila and Photorhabdus luminescens. Attacin and cecropin in the larvae treated with S. carpocapsae at 8 hr post-injection (PI) attained the maximum expression levels and were 138.42-fold and 65.84-fold greater than those of larvae infected with H. bacteriophora, respectively. Generally, the ability of H. bacteriophora to suppress attacin, cecropin, and spodoptericin was greater than that of S. carpocapsae. According to the results, the expression of AMPs by Sp. exigua larvae against S. carpocapsae was determined in the 4 statuses of monoxenic nematode, axenic nematode, live symbiotic bacterium, and dead symbiotic bacterium. The expression of attacin in larvae treated with a monoxenic nematode and live bacterium at 8 and 2 hr PI, respectively, were increased to the maximum amount. Live X. nematophila was the strongest agent for the suppression of attacin. The expression of cecropin against monoxenic nematodes and live symbiotic bacteria at 8 and 4 hr PI, respectively, reached the maximum amount while the expression levels of attacin and cecropin for axenic nematodes were lesser and stable. The results highlighted that the ability of P. luminescens in AMPs suppression was much more than X. nematophila. The results also showed that the effect of symbiotic bacterium in suppressing attacin and

  12. Current strategies for improving food bacteria

    NARCIS (Netherlands)

    Kuipers, O P; Buist, Girbe; Kok, Jan

    2000-01-01

    Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in

  13. FECAL COLIFORM BACTERIA AND FACTORS RELATED TO ITS GROWTH AT THE SEKOTONG SHALLOW WELLS, WEST NUSA TENGGARA, INDONESIA

    OpenAIRE

    Doni Marisi Sinaga; Mark Gregory Robson; Beatrix Trikurnia Gasong; Adonia Getse Halel; Dian Pertiwi

    2016-01-01

    Background: The poor sanitation and small numbers of households who own toilet in Sekotong regency may relate to the diarrheal events due to the fecal coliform contamination in drinking water. Aim: This paper aims to provide the concentrations of fecal coliform bacteria in shallow well waters and the factors associated to its growth. Method: Fifteen groundwater samples were collected from 5 shallow wells to provide the concentrations of total fecal coliform bacteria (FC), mercury conce...

  14. Oligotrophic bacteria isolated from clinical materials.

    OpenAIRE

    Tada, Y; Ihmori, M; Yamaguchi, J

    1995-01-01

    Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

  15. New criteria for selecting the origin of DNA replication in Wolbachia and closely related bacteria

    DEFF Research Database (Denmark)

    Ioannidis, Panagiotis; Dunning Hotopp, Julie C; Sapountzis, Panagiotis

    2007-01-01

    , the origin of DNA replication (ori) regions were identified in silico for Wolbachia strains and eleven other related bacteria belonging to Ehrlichia, Anaplasma, and Rickettsia genera. These features include DnaA-, CtrA- and IHF-binding sites as well as the flanking genes in C. crescentus. The Wolbachia ori...

  16. Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter.

    Science.gov (United States)

    Liu, Huan; Zhang, Xu; Zhang, Hao; Yao, Xiangwu; Zhou, Meng; Wang, Jiaqi; He, Zhanfei; Zhang, Huihui; Lou, Liping; Mao, Weihua; Zheng, Ping; Hu, Baolan

    2018-02-01

    In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers. Copyright © 2017 Elsevier Ltd

  17. High abundance of JS-1- and Chloroflexi-related Bacteria in deeply buried marine sediments revealed by quantitative, real-time PCR.

    Science.gov (United States)

    Blazejak, Anna; Schippers, Axel

    2010-05-01

    Sequences of members of the bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi are frequently found in 16S rRNA gene clone libraries obtained from marine sediments. Using a newly designed quantitative, real-time PCR assay, these bacterial groups were jointly quantified in samples from near-surface and deeply buried marine sediments from the Peru margin, the Black Sea, and a forearc basin off the island of Sumatra. In near-surface sediments, sequences of the JS-1 as well as Anaerolineae- and Caldilineae-related Bacteria were quantified with significantly lower 16S rRNA gene copy numbers than the sequences of total Bacteria. In contrast, in deeply buried sediments below approximately 1 m depth, similar quantities of the 16S rRNA gene copies of these specific groups and Bacteria were found. This finding indicates that JS-1 and Anaerolineae- and Caldilineae-related Bacteria might dominate the bacterial community in deeply buried marine sediments and thus seem to play an important ecological role in the deep biosphere.

  18. Extracellular deoxyribonuclease production by periodontal bacteria.

    Science.gov (United States)

    Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

    2012-08-01

    Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

  19. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Alix M Denoncourt

    2014-05-01

    Full Text Available Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

  20. The specificity of immune priming in silkworm, Bombyx mori, is mediated by the phagocytic ability of granular cells.

    Science.gov (United States)

    Wu, Gongqing; Li, Mei; Liu, Yi; Ding, Ying; Yi, Yunhong

    2015-10-01

    In the past decade, the phenomenon of immune priming was documented in many invertebrates in a large number of studies; however, in most of these studies, behavioral evidence was used to identify the immune priming. The underlying mechanism and the degree of specificity of the priming response remain unclear. We studied the mechanism of immune priming in the larvae of the silkworm, Bombyx mori, and analyzed the specificity of the priming response using two closely related Gram-negative pathogenic bacteria (Photorhabdus luminescens TT01 and P. luminescens H06) and one Gram-positive pathogenic bacterium (Bacillus thuringiensis HD-1). Primed with heat-killed bacteria, the B. mori larvae were more likely to survive subsequent homologous exposure (the identical bacteria used in the priming and in the subsequent challenge) than heterologous (different bacteria used in the priming and subsequent exposure) exposure to live bacteria. This result indicated that the B. mori larvae possessed a strong immune priming response and revealed a degree of specificity to TT01, H06 and HD-1 bacteria. The degree of enhanced immune protection was positively correlated with the level of phagocytic ability of the granular cells and the antibacterial activity of the cell-free hemolymph. Moreover, the granular cells of the immune-primed larvae increased the phagocytosis of a previously encountered bacterial strain compared with other bacteria. Thus, the enhanced immune protection of the B. mori larvae after priming was mediated by the phagocytic ability of the granular cells and the antibacterial activity of the hemolymph; the specificity of the priming response was primarily attributed to the phagocytosis of bacteria by the granular cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  2. Granuloma Annulare and Morphea: Correlation with Borrelia burgdorferi Infections and Chlamydia-related Bacteria

    Directory of Open Access Journals (Sweden)

    Lauri Tolkki

    2017-12-01

    Full Text Available A retrospective study of 109 skin biopsies with granuloma annulare (GA or morphea histology from patients with suspected tick bite was performed. Biopsies were tested for cutaneous Borrelia burgdorferi DNA using PCR. The same biopsies were analysed for tick-borne novel agents, Chlamydia-related bacteria (members of the Chlamydiales order, using a PCR-based method. Borrelia DNA was detected in 7/73 (9.6% biopsies with GA and in 1/36 (2.8 % biopsies with morphea, while Chlamydiales DNA was found in 53/73 (72.6% biopsies with GA and 25/34 (73.4% biopsies with morphea. All Borrelia DNA-positive GA samples were also positive for Chlamydiales DNA. The Chlamydiales sequences detected in GA were heterogeneous and contained Waddliaceae and Rhabdochlamydiaceae bacteria, which are also present in Ixodes ricinus ticks, while the Chlamydiales sequences detected in morphea closely resembled those found in healthy skin. In conclusion, tick-mediated infections can trigger GA in some cases, while correlation of either Borrelia or Chlamydiales with morphea is unlikely.

  3. Characterization of the relative importance of human- and infrastructure-associated bacteria in grey water: a case study.

    Science.gov (United States)

    Keely, S P; Brinkman, N E; Zimmerman, B D; Wendell, D; Ekeren, K M; De Long, S K; Sharvelle, S; Garland, J L

    2015-07-01

    Development of efficacious grey water (GW) treatment systems would benefit from detailed knowledge of the bacterial composition of GW. Thus, the aim of this study was to characterize the bacterial composition from (i) various points throughout a GW recycling system that collects shower and sink handwash (SH) water into an equalization tank (ET) prior to treatment and (ii) laundry (LA) water effluent of a commercial-scale washer. Bacterial composition was analysed by high-throughput pyrosequencing of the 16S rRNA gene. LA was dominated by skin-associated bacteria, with Corynebacterium, Staphylococcus, Micrococcus, Propionibacterium and Lactobacillus collectively accounting for nearly 50% of the total sequences. SH contained a more evenly distributed community than LA, with some overlap (e.g. Propionibacterium), but also contained distinct genera common to wastewater infrastructure (e.g. Zoogloea). The ET contained many of these same wastewater infrastructure-associated bacteria, but was dominated by genera adapted for anaerobic conditions. The data indicate that a relatively consistent set of skin-associated genera are the dominant human-associated bacteria in GW, but infrastructure-associated bacteria from the GW collection system and ET used for transient storage will be the most common bacteria entering GW treatment and reuse systems. This study is the first to use high-throughput sequencing to identify the bacterial composition of various GW sources. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  4. Lipopolysaccharides in diazotrophic bacteria.

    Science.gov (United States)

    Serrato, Rodrigo V

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

  5. Fungi, beta-Glucan, and Bacteria in Nasal Lavage of Greenhouse Workers and Their Relation to Occupational Exposure

    DEFF Research Database (Denmark)

    Madsen, A. M.; Tendal, K.; Thilsing, T.

    2013-01-01

    occupational exposure to fungi, -glucan, and bacteria and contents of fungi, -glucan, and bacteria in nasal lavage (NAL) of greenhouse workers. We also studied whether contents of microorganisms in NAL were related to gender, time of the work week, and runny nose. NAL samples (n 135) were taken Monday morning....... The ratios of fungi in NAL between Thursday at noon and Monday morning were 14 (median value) for men and 3.5 for women. Gender had no effect on the exposure level but had a significant effect on the content of fungi, -glucan, and bacteria in NAL, with the highest contents in NAL of men. On Thursdays......, the median content of fungi in NAL samples of men without runny noses was 9408 cfu per NAL sample, whereas the same content for women was 595 cfu per NAL sample. Workers with runny noses had fewer fungi in NAL than workers without runny noses. A higher content of -glucan per fungal spore was found in NAL...

  6. Location-Related Differences in Weathering Behaviors and Populations of Culturable Rock-Weathering Bacteria Along a Hillside of a Rock Mountain.

    Science.gov (United States)

    Wang, Qi; Wang, Rongrong; He, Linyan; Sheng, Xiafang

    2017-05-01

    Bacteria play important roles in rock weathering, elemental cycling, and soil formation. However, little is known about the weathering potential and population of bacteria inhabiting surfaces of rocks. In this study, we isolated bacteria from the top, middle, and bottom rock samples along a hillside of a rock (trachyte) mountain as well as adjacent soils and characterized rock-weathering behaviors and populations of the bacteria. Per gram of rock or surface soil, 10 6 -10 7 colony forming units were obtained and total 192 bacteria were isolated. Laboratory rock dissolution experiments indicated that the proportions of the highly effective Fe (ranging from 67 to 92 %), Al (ranging from 40 to 48 %), and Cu (ranging from 54 to 81 %) solubilizers were significantly higher in the top rock and soil samples, while the proportion of the highly effective Si (56 %) solubilizers was significantly higher in the middle rock samples. Furthermore, 78, 96, and 6 % of bacteria from the top rocks, soils, and middle rocks, respectively, significantly acidified the culture medium (pH bacteria (79 %) from the rocks were different to those from the soils and most of them (species level) have not been previously reported. Furthermore, location-specific rock-weathering bacterial populations were found and Bacillus species were the most (66 %) frequently isolated rock-weathering bacteria in the rocks based on cultivation methods. Notably, the top rocks and soils had the highest and lowest diversity of rock-weathering bacterial populations, respectively. The results suggested location-related differences in element (Si, Al, Fe, and Cu) releasing effectiveness and communities of rock-weathering bacteria along the hillside of the rock mountain.

  7. Determination of common pathogenic bacteria of blast injury to the limbs in plateau area and related research

    Directory of Open Access Journals (Sweden)

    Zheng-lei WANG

    2015-11-01

    Full Text Available Objective To investigate the common pathogenic bacteria and their drug susceptibility in the wounds in the limbs as a result of blast injury in plateau with a low temperature so as to provide a basis for prevention and treatment of war wound infection in such area. Methods The model of blast injury was reproduced to the hind legs of 800 rabbits in cold and dry plateau. 1, 3, 6, 12, 24, 48, 72 and 96h after injury, the general condition and vital signs of the wounded were observed, and bacterial culture, flora analysis and drug susceptibility test of excretion from wound tract, air, surface of snow, soil and animal fur were performed. Results Micrococciand Bacilliwere found in air and snow. Bacillus subtilis, Escherichia coliand Pseudomonas aeruginosawere found in soil, and Staphylococcus aureus, Acinetobacters, Pseudomonas aeruginosaand Escherichia coliin rabbit fur. The respiration and pulse became faster, and body temperature lowered after injury compared with that before injury. G+ bacteria were found in most wound tract secretions, and the frequency of the bacterial strains in descending order were Bacillus subtilis, coagulase-negative Staphylococci, E. coli, Pseudomonas aeruginosa, Stenotrophomonas maltophiliastrains. The sensitive antibiotics for these G+ bacteria were ofloxacin, ciprofloxacin, erythromycin. Susceptible G– bacteria were susceptible to ceftazidime, minocycline, sulfamethoxazole etc. Conclusions The growth of bacteria in the wounds as a result of blast injury grow slower in cold and dry alpine area. The time of debridement may be delayed for 2-3h. G+ bacteria were main susceptible flora to antibiotics, and it is related to the bacterial flora of the surrounding environment, thus it is suggested that a combination of different antibiotics (ofloxacin, ciprofloxacin or erythromycin alone combined with ceftazidime, minocycline or cotrimoxazole alone are needed to prevent infection after blast injury. DOI: 10.11855/j

  8. Increased levels of deleted in malignant brain tumours 1 (DMBT1) in active bacteria-related appendicitis

    DEFF Research Database (Denmark)

    Kaemmerer, Elke; Schneider, Ursula; Klaus, Christina

    2012-01-01

    Kaemmerer E, Schneider U, Klaus C, Plum P, Reinartz A, Adolf M, Renner M, Wolfs T G A M, Kramer B W, Wagner N, Mollenhauer J & Gassler N (2012) Histopathology Increased levels of deleted in malignant brain tumours 1 (DMBT1) in active bacteria-related appendicitis Aims:  Deleted in malignant brain...

  9. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  10. Periodontal bacteria in the genital tract: are they related to adverse pregnancy outcome?

    Science.gov (United States)

    Cassini, M A; Pilloni, A; Condò, S G; Vitali, L A; Pasquantonio, G; Cerroni, L

    2013-01-01

    One of the most important factors implicated in preterm birth (PTB) is acute genitourinary tract infection. The bacteria causing chronic periodontal inflammation include Gram-negative rods and anaerobes similar to those found in women with bacterial vaginosis. The aim of this prospective study is to investigate the relationship between oral and vaginal microflora and preterm low birth weight. Real-time polymerase chain reaction was used to detect both the presence and level of six periodontitis-related species: Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), Fusobacterium nucleatum ssp(Fn), and Prevotella intermedia (Pi) for both oral samples of subgingival plaque and cervical samples, obtained from 80 patients, during gynaecological examinations. The more representative oral pathogen (less than 60 percent) species in oral samples of preterm and term group were Tf, Td, and Fn. 24.4 percent of pregnant women presented periodontal pathogens in vaginal swab; the most representative species with a percentage over 0.1 percent of total bacteria in genital tract of preterm group were Tf, Td, and Piwith a positive correlation (less than 0.5). The presence of the bacterium T. denticolain the vagina, regardless of the amount, adversely affects preterm delivery.

  11. Isolation of cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and molecular comparison with dairy-related Lactobacillus helveticus strains

    DEFF Research Database (Denmark)

    Jensen, Marie Elisabeth Penderup; Ardö, Ylva Margareta; Vogensen, Finn Kvist

    2009-01-01

    -related Lact. helveticus strains indicated that one isolate was a Lact. helveticus. Partial sequencing of 16S rRNA confirmed this, and the remaining four strains were identified as Lactobacillus delbrueckii, Lactobacillus fermentum and Enterococcus faecium. The rep-PCR profile of the isolated Lact. helveticus......Aims: To isolate cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and compare them with dairy-related Lactobacillus helveticus strains using molecular typing methods. Methods and Results: The number of thermophilic bacteria in seven commercial cheeses...

  12. Microscopic Examination of Distribution and Phenotypic Properties of Phylogenetically Diverse Chloroflexaceae-Related Bacteria in Hot Spring Microbial Mats

    DEFF Research Database (Denmark)

    Nübel, U.; Bateson, Mary M.; Vandieken, V.

    2002-01-01

    We investigated the diversity, distribution, and phenotypes of uncultivated Chloroflexaceae-related bacteria in photosynthetic microbial mats of an alkaline hot spring (Mushroom Spring, Yellowstone National Park). By applying a directed PCR approach, molecular cloning, and sequence analysis of 16S...

  13. Sulfur metabolism in Escherichia coli and related bacteria: facts and fiction.

    Science.gov (United States)

    Sekowska, A; Kung, H F; Danchin, A

    2000-04-01

    Living organisms are composed of macromolecules made of hydrogen, carbon, nitrogen, oxygen, phosphorus and sulfur. Much work has been devoted to the metabolism of the first five elements, but much remains to be understood about sulfur metabolism. We review here the situation in Escherichia coli and related bacteria, where more than one hundred genes involved in sulfur metabolism have already been discovered in this organism. Examination of the genome suggests that many more will be found, especially genes involved in regulation, scavenging of sulfur containing molecules and synthesis of coenzymes or prosthetic groups. Furthermore, the involvement of methionine as the universal start of proteins as well as that of its derivative S-adenosylmethionine in a vast variety of cell processes argue in favour of a major importance of sulfur metabolism in all organisms.

  14. Sensitivity of spoiling and pathogen food-related bacteria to Origanum vulgare L. (Lamiaceae) essential oil

    OpenAIRE

    Souza,Evandro Leite de; Stamford,Tânia Lúcia Montenegro; Lima,Edeltrudes de Oliveira

    2006-01-01

    Origanum vulgare L. (oregano), Lamiaceae, has been known as plant specie with prominent biological properties for a long time. This study aimed to evaluate the antibacterial activity of Origanum vulgare essential oil on various Gram-positive and Gram-negative spoiling and/or pathogen food-related bacteria, as well as to observe its antimicrobial effectiveness in a food conservation micromodel. The results showed a strong antibacterial activity of the assayed essential oil noted by large growt...

  15. Anaerobic bacteria

    Science.gov (United States)

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  16. Digital imaging information technology for biospeckle activity assessment relative to bacteria and parasites.

    Science.gov (United States)

    Ramírez-Miquet, Evelio E; Cabrera, Humberto; Grassi, Hilda C; de J Andrades, Efrén; Otero, Isabel; Rodríguez, Dania; Darias, Juan G

    2017-08-01

    This paper reports on the biospeckle processing of biological activity using a visualization scheme based upon the digital imaging information technology. Activity relative to bacterial growth in agar plates and to parasites affected by a drug is monitored via the speckle patterns generated by a coherent source incident on the microorganisms. We present experimental results to demonstrate the potential application of this methodology for following the activity in time. The digital imaging information technology is an alternative visualization enabling the study of speckle dynamics, which is correlated to the activity of bacteria and parasites. In this method, the changes in Red-Green-Blue (RGB) color component density are considered as markers of the growth of bacteria and parasites motility in presence of a drug. The RGB data was used to generate a two-dimensional surface plot allowing an analysis of color distribution on the speckle images. The proposed visualization is compared to the outcomes of the generalized differences and the temporal difference. A quantification of the activity is performed using a parameterization of the temporal difference method. The adopted digital image processing technique has been found suitable to monitor motility and morphological changes in the bacterial population over time and to detect and distinguish a short term drug action on parasites.

  17. Relative contributions of archaea and bacteria to microbial ammonia oxidation differ under different conditions during agricultural waste composting.

    Science.gov (United States)

    Zeng, Guangming; Zhang, Jiachao; Chen, Yaoning; Yu, Zhen; Yu, Man; Li, Hui; Liu, Zhifeng; Chen, Ming; Lu, Lunhui; Hu, Chunxiao

    2011-10-01

    The aim of this study was to compare the relative contribution of ammonia-oxidizing archaea (AOA) and bacteria (AOB) to nitrification during agricultural waste composting. The AOA and AOB amoA gene abundance and composition were determined by quantitative PCR and denaturing gradient gel electrophoresis (DGGE), respectively. The results showed that the archaeal amoA gene was abundant throughout the composting process, while the bacterial amoA gene abundance decreased to undetectable level during the thermophilic and cooling stages. DGGE showed more diverse archaeal amoA gene composition when the potential ammonia oxidation (PAO) rate reached peak values. A significant positive relationship was observed between the PAO rate and the archaeal amoA gene abundance (R²=0.554; Parchaea dominated ammonia oxidation during the thermophilic and cooling stages. Bacteria were also related to ammonia oxidation activity (R²=0.503; P=0.03) especially during the mesophilic and maturation stages. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  19. A designated centre for people with disabilities operated by St John of God Community Services Ltd, Louth

    LENUS (Irish Health Repository)

    Jones, Robert T

    2010-05-12

    Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C) and human (37°C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of

  20. Interactions between bacteria and solid surfaces in relation to bacterial transport in porous media

    NARCIS (Netherlands)

    Rijnaarts, H.H.M.

    1994-01-01

    Interactions between bacteria and solid surfaces strongly influence the behaviour of bacteria in natural and engineered ecosystems. Many biofilm reactors and terrestrial environments are porous media. The purpose of the research presented in this thesis is to gain a better insight into the

  1. Reconditioning of soils degraded through oil contamination using bacteria relating to thiosphaera

    International Nuclear Information System (INIS)

    Sakhno, T.V.; Kurashov, V.M.; Kolesnik, A.A.; Morozkin, A.I.; Gavrilov, V.S.

    2005-01-01

    Bio-preparations based on aerobic bacteria are conventionally used to decontaminate soils of oil. There is a problem of no effect in oil decomposing by using conventional bio-preparations in soils where the depth of oil penetration into the soil exceeds 60 cm in the case of oil outflow. At deep oil penetration into the soil, the efficiency of oil biodegradation with aerobic hydrocarbon oxidizing microorganisms is limited by the factor of oxygen accessibility (oxygen limit). We used Thiosphaera pantotropha as a mono-culture and together with a culture of Pseudomonas putida to solve this problem. Pseudomonas putida being aerobes decompose oil effectively at oil concentration up to 25 g of oil in 1 kg of soil and at the depth of oil penetration into the soil up to 25-30 cm. At a deeper level of soil, the activity of Pseudomonas putida falls because of oxygen limit. At the depth of 60 cm and deeper, Pseudomonas putida stop oxidize and decompose oil because of the limited oxygen accessibility. Bacteria of Thiosphaera pantotropha being elective anaerobes decompose oil both in the presence and in the absence of oxygen, and at low concentrations of oxygen insufficient for vital functions of obligate aerobic species of bacteria. Thus, bacteria of Thiosphaera pantotropha decompose hydrocarbons independently on the depth of oil penetration into the soil. Due to special features of their metabolism, bacteria of Thiosphaera pantotropha can realize their vital functions and decompose hydrocarbons at high oil concentrations in soils at which conventionally used bio-preparations can not be effective. We found out that Thiosphaera decompose sulfurous closed-ring and aromatic compounds in oil which are chemically and thermally stable and can be hardly decomposed, and possess extremely poisonous properties, as well. The use of microorganisms of Thiosphaera pantotropha allows to purify soils polluted with oil and oil products. The results obtained are applied to the cleaning of

  2. Application of hierarchical oligonucleotide primer extension (HOPE) to assess relative abundances of ammonia- and nitrite-oxidizing bacteria

    KAUST Repository

    Scarascia, Giantommaso

    2017-04-04

    Background: Establishing an optimal proportion of nitrifying microbial populations, including ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), complete nitrite oxidizers (comammox) and ammonia-oxidizing archaea (AOA), is important for ensuring the efficiency of nitrification in water treatment systems. Hierarchical oligonucleotide primer extension (HOPE), previously developed to rapidly quantify relative abundances of specific microbial groups of interest, was applied in this study to track the abundances of the important nitrifying bacterial populations. Results: The method was tested against biomass obtained from a laboratory-scale biofilm-based trickling reactor, and the findings were validated against those obtained by 16S rRNA gene-based amplicon sequencing. Our findings indicated a good correlation between the relative abundance of nitrifying bacterial populations obtained using both HOPE and amplicon sequencing. HOPE showed a significant increase in the relative abundance of AOB, specifically Nitrosomonas, with increasing ammonium content and shock loading (p < 0.001). In contrast, Nitrosospira remained stable in its relative abundance against the total community throughout the operational phases. There was a corresponding significant decrease in the relative abundance of NOB, specifically Nitrospira and those affiliated to comammox, during the shock loading. Based on the relative abundance of AOB and NOB (including commamox) obtained from HOPE, it was determined that the optimal ratio of AOB against NOB ranged from 0.2 to 2.5 during stable reactor performance. Conclusions: Overall, the HOPE method was developed and validated against 16S rRNA gene-based amplicon sequencing for the purpose of performing simultaneous monitoring of relative abundance of nitrifying populations. Quantitative measurements of these nitrifying populations obtained via HOPE would be indicative of reactor performance and nitrification functionality.

  3. RNases and Helicases in Gram-Positive Bacteria.

    Science.gov (United States)

    Durand, Sylvain; Condon, Ciaran

    2018-04-01

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

  4. Bacteria Associated with Fresh Tilapia Fish (Oreochromis niloticus ...

    African Journals Online (AJOL)

    acer

    Keywords: Bacteria, Tilapia fish and Sokoto central market. INTRODUCTION ... The bacteria are transmitted by fish that have made contact ... with which a product spoils is also related to the .... Base on the percentage frequency of occurance ,.

  5. Developing new bacteria subroutines in the SWAT model

    Science.gov (United States)

    Fecal bacteria observations from four different sites in Korea and the US demonstrate seasonal variability, showing a significant relationship with temperature (Figure 1); fecal indicator bacteria (FIB) concentrations are relatively higher in summer and lower in winter , including Stillwater river (...

  6. Bactericidal activity of the Ti-13Nb-13Zr alloy against different species of bacteria related with implant infection.

    Science.gov (United States)

    Aguilera-Correa, John-Jairo; Conde, Ana; Arenas, Maria-Angeles; de-Damborenea, Juan-Jose; Marin, Miguel; Doadrio, Antonio L; Esteban, Jaime

    2017-08-11

    The Ti-6Al-4V alloy is one of the most commonly used in orthopedic surgery. Despite its advantages, there is an increasing need to use new titanium alloys with no toxic elements and improved biomechanical properties, such as Ti-13Nb-13Zr. Prosthetic joint infections (PJI) are mainly caused by Gram-positive bacteria; however, Gram-negative bacteria are a growing problem due to associated multidrug resistance. In this study, the bacterial adherence and viability on the Ti-13Nb-13Zr alloy have been compared to that of the Ti-6Al-4V alloy using 16 collection and clinical strains of bacterial species related to PJI: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa. When compared with the Ti-6Al-4V alloy, bacterial adherence on the Ti-13Nb-13Zr alloy was significantly higher in most staphylococcal and P. aeruginosa strains and lower for E. coli strains. The proportion of live bacteria was significantly lower for both Gram-negative species on the Ti-13Nb-13Zr alloy than on the Ti-6Al-4V alloy pointing to some bactericidal effect of the Ti-13Nb-13Zr alloy. This bactericidal effect appears to be a consequence of the formation of hydroxyl radicals, since this effect is neutralized when dimethylsulfoxide was added to both the saline solution and water used to wash the stain. The antibacterial effect of the Ti-13Nb-13Zr alloy against Gram-negative bacteria is an interesting property useful for the prevention of PJI caused by these bacteria on this potential alternative to the Ti-6Al-4V alloy for orthopedic surgery.

  7. Periodontal Therapy Effects on Nitrite Related to Oral Bacteria: A 6-Month Randomized Clinical Trial.

    Science.gov (United States)

    Cortelli, Sheila C; Costa, Fernando O; Rodrigues, Edson; Cota, Luis O M; Cortelli, Jose R

    2015-08-01

    Nitrite is a biologic factor relevant to oral and systemic homeostasis. Through an oral bacteria reduction process, it was suggested that periodontal therapy and chlorhexidine (CHX) rinse could affect nitrite levels, leading to negative effects, such as an increase in blood pressure. This 6-month randomized clinical trial evaluated the effects of periodontal therapeutic protocols on salivary nitrite and its relation to subgingival bacteria. One hundred patients with periodontitis were allocated randomly to debridement procedures in four weekly sections (quadrant scaling [QS]) or within 24 hours (full-mouth scaling [FMS]) in conjunction with a 60-day CHX (QS + CHX and FMS + CHX), placebo (QS + placebo and FMS + placebo), or no mouthrinse (QS + none and FMS + none) use. Real-time polymerase chain reaction determined total bacterial, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Streptococcus oralis, and Actinomyces naeslundii levels. Salivary nitrite concentration was determined with Griess reagent. Data were analyzed statistically at baseline and 3 and 6 months by analysis of variance, Kruskal-Wallis, Mann-Whitney U, and Spearman correlation tests (P periodontal pockets. The relationship between nitrite and bacterial levels appears weak. Short-term scaling exhibited a greater influence on nitrite concentrations then long-term CHX use.

  8. Luminous bacteria cultured from fish guts in the Gulf of Oman.

    Science.gov (United States)

    Makemson, J C; Hermosa, G V

    1999-01-01

    The incidence of culturable luminous bacteria in Omani market fish guts was correlated to habitat type amongst 109 species of fish. Isolated representative luminous bacteria were compared to known species using the Biolog system (95 traits/isolate) and cluster analysis, which showed that the main taxa present in fish guts were clades related to Vibrio harveyi and Photobacterium species with sporadic incidence of P. phosphoreum. The luminous isolates from gut of the slip-mouth (barred pony fish), Leiognathus fasciatus, were mainly a type related to Photobacterium but phenotypically different from known species. These luminous gut bacteria were identical with the bacteria in the light organ, indicating that the light organ supplies a significant quantity of luminous bacteria to the gut. In many of the fish that lack light organs, luminous bacteria were also the dominant bacterial type in the gut, while in some others luminous bacteria were encountered sporadically and at low densities, reflecting the incidence of culturable luminous bacteria in seawater. Pelagic fish contained the highest incidence of culturable luminous bacteria and reef-associated fish the lowest. No correlation was found between the incidence of culturable luminous bacteria and the degree to which fish produce a melanin-covered gut. Copyright 1999 John Wiley & Sons, Ltd.

  9. Emerging role of bacteria in oral carcinogenesis: a review with special reference to perio-pathogenic bacteria.

    Science.gov (United States)

    Perera, Manosha; Al-Hebshi, Nezar Noor; Speicher, David J; Perera, Irosha; Johnson, Newell W

    2016-01-01

    Oral cancer, primarily oral squamous cell carcinoma (OSCC), continues to be a major global health problem with high incidence and low survival rates. While the major risk factors for this malignancy, mostly lifestyle related, have been identified, around 15% of oral cancer cases remain unexplained. In light of evidence implicating bacteria in the aetiology of some cancer types, several epidemiological studies have been conducted in the last decade, employing methodologies ranging from traditional culture techniques to 16S rRNA metagenomics, to assess the possible role of bacteria in OSCC. While these studies have demonstrated differences in microbial composition between cancerous and healthy tissues, they have failed to agree on specific bacteria or patterns of oral microbial dysbiosis to implicate in OSCC. On the contrary, some oral taxa, particularly Porphyromonas gingivalis and Fusobacterium nucleatum, show strong oral carcinogenic potential in vitro and in animal studies. Bacteria are thought to contribute to oral carcinogenesis via inhibition of apoptosis, activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation, and production of carcinogens. This narrative review provides a critical analysis of and an update on the association between bacteria and oral carcinogenesis and the possible mechanisms underlying it.

  10. Isolation of radiation-resistant bacteria without exposure to irradiation

    International Nuclear Information System (INIS)

    Sanders, S.W.; Maxcy, R.B.

    1979-01-01

    Resistance to desiccation was utilized in the selection of highly radiation-resistant asporogenous bacteria from nonirradiated sources. A bacterial suspension in phosphate buffer was dried in a thin film at 25 0 C and 33% relative humidity. Storage under these conditions for 15 days or more reduced the number of radiation-sensitive bacteria. Further selection for radiation-resistant bacteria was obtained by irradiation of bacteria on velveteen in the replication process, therby avoiding the toxic effect of irradiated media. The similarity of radiation resistance and identifying characteristics in irradiated and non-irradiated isolates should allay some concerns that highly radiation-resistance bacteria have been permanently altered by radiation selection

  11. Mimicking microbial interactions under nitrate-reducing conditions in an anoxic bioreactor: enrichment of novel Nitrospirae bacteria distantly related to Thermodesulfovibrio.

    Science.gov (United States)

    Arshad, Arslan; Dalcin Martins, Paula; Frank, Jeroen; Jetten, Mike S M; Op den Camp, Huub J M; Welte, Cornelia U

    2017-12-01

    Microorganisms are main drivers of the sulfur, nitrogen and carbon biogeochemical cycles. These elemental cycles are interconnected by the activity of different guilds in sediments or wastewater treatment systems. Here, we investigated a nitrate-reducing microbial community in a laboratory-scale bioreactor model that closely mimicked estuary or brackish sediment conditions. The bioreactor simultaneously consumed sulfide, methane and ammonium at the expense of nitrate. Ammonium oxidation occurred solely by the activity of anammox bacteria identified as Candidatus Scalindua brodae and Ca. Kuenenia stuttgartiensis. Fifty-three percent of methane oxidation was catalyzed by archaea affiliated to Ca. Methanoperedens and 47% by Ca. Methylomirabilis bacteria. Sulfide oxidation was mainly shared between two proteobacterial groups. Interestingly, competition for nitrate did not lead to exclusion of one particular group. Metagenomic analysis showed that the most abundant taxonomic group was distantly related to Thermodesulfovibrio sp. (87-89% 16S rRNA gene identity, 52-54% average amino acid identity), representing a new family within the Nitrospirae phylum. A high quality draft genome of the new species was recovered, and analysis showed high metabolic versatility. Related microbial groups are found in diverse environments with sulfur, nitrogen and methane cycling, indicating that these novel Nitrospirae bacteria might contribute to biogeochemical cycling in natural habitats. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Epithermal Neutron Activation Analysis (ENAA) of Cr(VI)-reducer Basalt-inhabiting Bacteria

    CERN Document Server

    Tsibakhashvili, N Ya; Kirkesali, E I; Aksenova, N G; Kalabegishvili, T L; Murusidze, I G; Mosulishvili, L M; Holman, H Y N

    2005-01-01

    Epithermal neutron activation analysis (ENAA) has been applied to studying elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance (ESR) demonstrating that the bacteria differ in the rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 $\\mu $g/g of dry weight) indicate bacterial adaptation to the environmental condition...

  13. Phylogenetic diversity of bacteria associated with toxic and non-toxic ...

    African Journals Online (AJOL)

    Phylogenetic diversity of bacteria associated with toxic and non-toxic strains of Alexandrium minutum. L Palacios, B Reguera, J Franco, I Marín. Abstract. Marine planktonic dinoflagellates are usually associated with bacteria, some of which seem to have a symbiotic relation with the dinoflagellate cells. The role of bacteria in ...

  14. Magnetosome chain superstructure in uncultured magnetotactic bacteria

    International Nuclear Information System (INIS)

    Abraçado, Leida G; Farina, Marcos; Abreu, Fernanda; Keim, Carolina N; Lins, Ulysses; Campos, Andrea P C

    2010-01-01

    Magnetotactic bacteria produce magnetosomes, which are magnetic particles enveloped by biological membranes, in a highly controlled mineralization process. Magnetosomes are used to navigate in magnetic fields by a phenomenon called magnetotaxis. Two levels of organization and control are recognized in magnetosomes. First, magnetotactic bacteria create a spatially distinct environment within vesicles defined by their membranes. In the vesicles, the bacteria control the size, composition and purity of the mineral content of the magnetic particles. Unique crystal morphologies are produced in magnetosomes as a consequence of this bacterial control. Second, magnetotactic bacteria organize the magnetosomes in chains within the cell body. It has been shown in a particular case that the chains are positioned within the cell body in specific locations defined by filamentous cytoskeleton elements. Here, we describe an additional level of organization of the magnetosome chains in uncultured magnetotactic cocci found in marine and freshwater sediments. Electron microscopy analysis of the magnetosome chains using a goniometer showed that the magnetic crystals in both types of bacteria are not oriented at random along the crystal chain. Instead, the magnetosomes have specific orientations relative to the other magnetosomes in the chain. Each crystal is rotated either 60°, 180° or 300° relative to their neighbors along the chain axis, causing the overlapping of the (1 1 1) and (1-bar 1-bar 1-bar) capping faces of neighboring crystals. We suggest that genetic determinants that are not present or active in bacteria with magnetosomes randomly rotated within a chain must be present in bacteria that organize magnetosomes so precisely. This particular organization may also be used as an indicative biosignature of magnetosomes in the study of magnetofossils in the cases where this symmetry is observed

  15. Resuscitation effects of catalase on airborne bacteria.

    OpenAIRE

    Marthi, B; Shaffer, B T; Lighthart, B; Ganio, L

    1991-01-01

    Catalase incorporation into enumeration media caused a significant increase (greater than 63%) in the colony-forming abilities of airborne bacteria. Incubation for 30 to 60 min of airborne bacteria in collection fluid containing catalase caused a greater than 95% increase in colony-forming ability. However, catalase did not have any effects on enumeration at high relative humidities (80 to 90%).

  16. Genome sequence and comparative analysis of a putative entomopathogenic Serratia isolated from Caenorhabditis briggsae.

    Science.gov (United States)

    Abebe-Akele, Feseha; Tisa, Louis S; Cooper, Vaughn S; Hatcher, Philip J; Abebe, Eyualem; Thomas, W Kelley

    2015-07-18

    Entomopathogenic associations between nematodes in the genera Steinernema and Heterorhabdus with their cognate bacteria from the bacterial genera Xenorhabdus and Photorhabdus, respectively, are extensively studied for their potential as biological control agents against invasive insect species. These two highly coevolved associations were results of convergent evolution. Given the natural abundance of bacteria, nematodes and insects, it is surprising that only these two associations with no intermediate forms are widely studied in the entomopathogenic context. Discovering analogous systems involving novel bacterial and nematode species would shed light on the evolutionary processes involved in the transition from free living organisms to obligatory partners in entomopathogenicity. We report the complete genome sequence of a new member of the enterobacterial genus Serratia that forms a putative entomopathogenic complex with Caenorhabditis briggsae. Analysis of the 5.04 MB chromosomal genome predicts 4599 protein coding genes, seven sets of ribosomal RNA genes, 84 tRNA genes and a 64.8 KB plasmid encoding 74 genes. Comparative genomic analysis with three of the previously sequenced Serratia species, S. marcescens DB11 and S. proteamaculans 568, and Serratia sp. AS12, revealed that these four representatives of the genus share a core set of ~3100 genes and extensive structural conservation. The newly identified species shares a more recent common ancestor with S. marcescens with 99% sequence identity in rDNA sequence and orthology across 85.6% of predicted genes. Of the 39 genes/operons implicated in the virulence, symbiosis, recolonization, immune evasion and bioconversion, 21 (53.8%) were present in Serratia while 33 (84.6%) and 35 (89%) were present in Xenorhabdus and Photorhabdus EPN bacteria respectively. The majority of unique sequences in Serratia sp. SCBI (South African Caenorhabditis briggsae Isolate) are found in ~29 genomic islands of 5 to 65 genes and are

  17. Epithermal neutron activation analysis of CR(VI)-reducer basalt-inhabiting bacteria

    International Nuclear Information System (INIS)

    Tsibakhashvili, N.Ya.; Kalabegishvili, T.L.; Murusidze, I.G.; Mosulishvili, L.M.; Frontas'eva, M.V.; Kirkesali, E.I.; Aksenova, N.G.; Holman, H.Y.

    2005-01-01

    Epithermal neutron activation analysis (ENAA) has been applied to studying elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance (ESR) demonstrating that the bacteria differ in the rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(VI) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 μg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements ranging from major- to ultratrace ones were determined in each type of bacteria simultaneously. The range of concentrations spans over 8 orders of magnitude

  18. Tolerance of anaerobic bacteria to chlorinated solvents.

    Science.gov (United States)

    Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

    2014-01-01

    The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

  19. Effect of fruiting body bacteria on the growth of Tricholoma matsutake and its related molds.

    Directory of Open Access Journals (Sweden)

    Seung-Yoon Oh

    Full Text Available Tricholoma matsutake (pine mushroom, PM is a prized mushroom in Asia due to its unique flavor and pine aroma. The fruiting body of PM forms only in its natural habitat (pine forest, and little is known regarding the natural conditions required for successful generation of the fruiting bodies in this species. Recent studies suggest that microbial interactions may be associated with the growth of PM; however, there have been few studies of the bacterial effects on PM growth. In this study, we surveyed which bacteria can directly and indirectly promote the growth of PM by using co-cultures with PM and molds associated with the fruiting body. Among 16 bacterial species isolated from the fruiting body, some species significantly influenced the mycelial growth of PM and molds. Most bacteria negatively affected PM growth and exhibited various enzyme activities, which suggests that they use the fruiting body as nutrient source. However, growth-promoting bacteria belonging to the Dietzia, Ewingella, Pseudomonas, Paenibacillus, and Rodococcus were also found. In addition, many bacteria suppressed molds, which suggests an indirect positive effect on PM as a biocontrol agent. Our results provide important insights toward a better understanding of the microbial interactions in the fruiting body of PM, and indicate that growth-promoting bacteria may be an important component in successful cultivation of PM.

  20. Effect of inorganic nutrients on relative contributions of fungi and bacteria to carbon flow from submerged decomposing leaf litter

    Science.gov (United States)

    Vladislav Gulis; Keller Suberkropp

    2003-01-01

    The relative contributions of fungi and bacteria to carbon flow from submerged decaying plant litter at different levels of inorganic nutrients (N and P) were studied. We estimated leaf mass loss, fungal and bacterial biomass and production, and microbial respiration and constructed partial carbon budgets for red maple leaf disks precolonized in a stream and then...

  1. Bacteria in non-woven textile filters for domestic wastewater treatment.

    Science.gov (United States)

    Spychała, Marcin; Starzyk, Justyna

    2015-01-01

    The objective of this study was preliminary identification of heterotrophic and ammonia oxidizing bacteria (AOB) cell concentration in the cross-sectional profile of geotextile filters for wastewater treatment. Filters of thicknesses 3.6 and 7.2 mm, made of non-woven textile TS20, were supplied with septic tank effluent and intermittently dosed and filtered under hydrostatic pressure. The cumulative loads of chemical oxygen demand (COD) and total solids were about 1.36 and 1.06 kg/cm2, respectively. The filters under analysis reached a relatively high removal efficiency for organic pollution 70-90% for biochemical oxygen demand (BOD5) and 60-85% for COD. The ammonia nitrogen removal efficiency level proved to be unstable (15-55%). Biomass samples for dry mass identification were taken from two regions: continuously flooded with wastewater and intermittently flooded with wastewater. The culturable heterotrophic bacteria were determined as colony-forming units (CFUs) on microbiological-selective media by means of the plate method. AOB and nitrite oxidizing bacteria (NOB) were examined using the FISH technique. A relatively wide range of heterotrophic bacteria was observed from 7.4×10(5)/cm2 to 3.8×10(6)/cm2 in geotextile layers. The highest concentration of heterotrophic bacteria (3.8×10(6)/cm2) was observed in the first layer of the textile filter. AOB were identified occasionally--about 8-15% of all bacteria colonizing the last filter layer, but occasionally much higher concentrations and ammonia nitrogen efficiency were achieved. Bacteria oxidizing nitrite to nitrate were not observed. The relation of total and organic fraction of biomass to culturable heterotrophic bacteria was also found.

  2. Bacterial 16S rRNA gene analysis revealed that bacteria related to Arcobacter spp. constitute an abundant and common component of the oyster microbiota (Tiostrea chilensis).

    Science.gov (United States)

    Romero, J; García-Varela, M; Laclette, J P; Espejo, R T

    2002-11-01

    To explore the bacterial microbiota in Chilean oyster (Tiostrea chilensis), a molecular approach that permits detection of different bacteria, independently of their capacity to grow in culture media, was used. Bacterial diversity was assessed by analysis of both the 16S rDNA and the 16S-23S intergenic region, obtained by PCR amplifications of DNA extracted from depurated oysters. RFLP of the PCR amplified 16S rDNA showed a prevailing pattern in most of the individuals analyzed, indicating that a few bacterial species were relatively abundant and common in oysters. Cloning and sequencing of the 16S rDNA with the prevailing RFLP pattern indicated that this rRNA was most closely related to Arcobacter spp. However, analysis by the size of the amplified 16S-23S rRNA intergenic regions revealed not Arcobacter spp. but Staphylococcus spp. related bacteria as a major and common component in oyster. These different results may be caused by the absence of target for one of the primers employed for amplification of the intergenic region. Neither of the two bacteria species found in large abundance was recovered after culturing under aerobic, anaerobic, or microaerophilic conditions. This result, however, is expected because the number of bacteria recovered after cultivation was less than 0.01% of the total. All together, these observations suggest that Arcobacter-related strains are probably abundant and common in the Chilean oyster bacterial microbiota.

  3. Bile anaerobic bacteria detection and antibiotic susceptibility in patients with gallstone.

    Science.gov (United States)

    Lu, Yun; Xiang, Ting-Hai; Shi, Jing-Sen; Zhang, Bing-Yuan

    2003-08-01

    To detect bile anaerobic bacteria and antibiotic susceptibility in 59 patients with gallstones who had had cholecystectomy. BACT/ALERT 120 microbe detection system and SCEPTOR microbe detection system were used to detect bile anaerobic bacteria, antibiotic susceptibility. The ratio of anaerobic bacteria to the patients examined was 52.5% (31/59). Obligate anaerobe bile culture showed positive results in 4 patients. B. fragilis (37.8%) was the major type of anaerobic bacteria in bile. Most (81.8%) of anaerobic bacteria were sensitive to metronidazole, and imipenem was suitable for beta-lactamase bacteria. Culture of anaerobic bacteria in logarithmic phase can improve the positive rate of the culture. There are some relations between anaerobic infection and gallstone formation.

  4. Virus–Bacteria Interactions: Implications and Potential for the Applied and Agricultural Sciences

    Directory of Open Access Journals (Sweden)

    Matthew D. Moore

    2018-02-01

    Full Text Available Eukaryotic virus–bacteria interactions have recently become an emerging topic of study due to multiple significant examples related to human pathogens of clinical interest. However, such omnipresent and likely important interactions for viruses and bacteria relevant to the applied and agricultural sciences have not been reviewed or compiled. The fundamental basis of this review is that these interactions have importance and deserve more investigation, as numerous potential consequences and applications arising from their discovery are relevant to the applied sciences. The purpose of this review is to highlight and summarize eukaryotic virus–bacteria findings in the food/water, horticultural, and animal sciences. In many cases in the agricultural sciences, mechanistic understandings of the effects of virus–bacteria interactions remain unstudied, and many studies solely focus on co-infections of bacterial and viral pathogens. Given recent findings relative to human viral pathogens, further research related to virus–bacteria interactions would likely result in numerous discoveries and beneficial applications.

  5. Virus-Bacteria Interactions: Implications and Potential for the Applied and Agricultural Sciences.

    Science.gov (United States)

    Moore, Matthew D; Jaykus, Lee-Ann

    2018-02-02

    Eukaryotic virus-bacteria interactions have recently become an emerging topic of study due to multiple significant examples related to human pathogens of clinical interest. However, such omnipresent and likely important interactions for viruses and bacteria relevant to the applied and agricultural sciences have not been reviewed or compiled. The fundamental basis of this review is that these interactions have importance and deserve more investigation, as numerous potential consequences and applications arising from their discovery are relevant to the applied sciences. The purpose of this review is to highlight and summarize eukaryotic virus-bacteria findings in the food/water, horticultural, and animal sciences. In many cases in the agricultural sciences, mechanistic understandings of the effects of virus-bacteria interactions remain unstudied, and many studies solely focus on co-infections of bacterial and viral pathogens. Given recent findings relative to human viral pathogens, further research related to virus-bacteria interactions would likely result in numerous discoveries and beneficial applications.

  6. Distribution of δ-aminolevulinic acid biosynthetic pathways among phototrophic and related bacteria

    International Nuclear Information System (INIS)

    Avissar, Y.J.; Beale, S.I.; Ormerod, J.G.

    1989-01-01

    Two biosynthetic pathways are known for the universal tetrapyrrole precursor, δ-aminolevulinic acid (ALA): condensation of glycine and succinyl-CoA to form ALA with the loss of C-1 of glycine as CO 2 , and conversion of the intact carbon skeleton of glutamate to ALA in a process requiring tRNA Glu , ATP, Mg 2+ , NADPH, and pyridoxal phosphate. The distribution of the two ALA biosynthetic pathways among various bacterial genera was determined, using cell-free extracts obtained from representative organisms. Evidence for the operation of the glutamate pathway was obtained by the measurement of RNase-sensitive label incorporation from glutamate into ALA using 3,4-[ 3 H]glutamate and 1-[ 14 C]glutamate as substrate. The glycine pathway was indicated by RNase-insensitive incorporation of level from 2-[ 14 C]glycine into ALA. The distribution of the two pathways among the bacteria tested was in general agreement with their previously phylogenetic relationships and clearly indicates that the glutamate pathway is the more ancient process, whereas the glycine pathway probably evolved much later. The glutamate pathway is the more widely utilized one among bacteria, while the glycine pathway is apparently limited to the α subgroup of purple bacteria (including Rhodobacter, Rhodospirillum, and Rhizobium). E. coli was found ALA via the glutamate pathway. The ALA-requiring hemA mutant of E. coli was determined to lack the dehydrogenase activity that utilizes glutamyl-tRNA as a substrate

  7. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    Carey, A.E.; Bowen, V.T.

    1978-01-01

    Microbes are important in geochemical cycling of many elements. Recent reports emphasize biogenous particulates and bacterial exometabolites as controlling oceanic distribution of plutonium. Bacteria perform oxidation/reduction reactions on metals such as mercury, nickel, lead, copper, and cadmium. Redox transformations or uptake of Pu by marine bacteria may well proceed by similar mechanisms. Profiles of water samples and sediment cores were obtained along the continental shelf off Nova Scotia and in the Gulf of St. Lawrence. Profiles of water samples, and sediment cores were obtained. Epifluorescent microscopy was used to view bacteria (from water or sediment) after concentration on membrane filters and staining with acridine orange. Radiochemical analyses measured Pu in sediments and water samples. Studies of 237 Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 10 4 to 10 5 cells/ml in seawater or 10 7 to 10 8 cells/gram of sediment. These numbers are related to the levels and distrbution of Pu in the samples. In cultures of L. mucor amended with Pu atom concentrations approximating those present in open ocean environments, bacterial cells concentrated 237 Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistry

  8. Antagonistic activity of isolated lactic acid bacteria from Pliek U against gram-negative bacteria Escherichia coli ATCC 25922

    Science.gov (United States)

    Kiti, A. A.; Jamilah, I.; Rusmarilin, H.

    2017-09-01

    Lactic acid bacteria (LAB) is one group of microbes that has many benefits, notably in food and health industries sector. LAB plays an important role in food fermentation and it has bacteriostatic effect against the growth of pathogenic microorganisms. The research related LAB continued to be done to increase the diversity of potential isolates derived from nature which is indigenous bacteria for biotechnological purposes. This study was aimed to isolate and characterize LAB derived from pliek u sample and to examine the potency to inhibits Escherichia coli ATCC 25922 bacteria growth. A total of 5 isolates were isolated and based on morphological and physiological characteristics of the fifth bacteria, they are allegedly belonging to the genus Bacillus. Result of antagonistic test showed that the five isolates could inhibits the growth of E. coli ATCC 25922. The highest inhibition zone is 8.5 mm was shown by isolates NQ2, while the lowest inhibition is 1.5 mm was shown by isolates NQ3.

  9. Maximum relative speeds of living organisms: Why do bacteria perform as fast as ostriches?

    Science.gov (United States)

    Meyer-Vernet, Nicole; Rospars, Jean-Pierre

    2016-12-01

    Self-locomotion is central to animal behaviour and survival. It is generally analysed by focusing on preferred speeds and gaits under particular biological and physical constraints. In the present paper we focus instead on the maximum speed and we study its order-of-magnitude scaling with body size, from bacteria to the largest terrestrial and aquatic organisms. Using data for about 460 species of various taxonomic groups, we find a maximum relative speed of the order of magnitude of ten body lengths per second over a 1020-fold mass range of running and swimming animals. This result implies a locomotor time scale of the order of one tenth of second, virtually independent on body size, anatomy and locomotion style, whose ubiquity requires an explanation building on basic properties of motile organisms. From first-principle estimates, we relate this generic time scale to other basic biological properties, using in particular the recent generalisation of the muscle specific tension to molecular motors. Finally, we go a step further by relating this time scale to still more basic quantities, as environmental conditions at Earth in addition to fundamental physical and chemical constants.

  10. A porous silicon optical microcavity for sensitive bacteria detection

    International Nuclear Information System (INIS)

    Li Sha; Huang Jianfeng; Cai Lintao

    2011-01-01

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (∼10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml -1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml -1 . The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  11. A porous silicon optical microcavity for sensitive bacteria detection

    Science.gov (United States)

    Li, Sha; Huang, Jianfeng; Cai, Lintao

    2011-10-01

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (~10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml - 1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml - 1. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  12. A porous silicon optical microcavity for sensitive bacteria detection

    Energy Technology Data Exchange (ETDEWEB)

    Li Sha; Huang Jianfeng; Cai Lintao, E-mail: lt.cai@siat.ac.cn [CAS Key Lab of Health Informatics, Shenzhen Key Laboratory of Cancer Nanotechnology, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)

    2011-10-21

    A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak ({approx}10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml{sup -1} at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml{sup -1}. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

  13. Physiological and genetics studies of highly radiation-resistant bacteria

    International Nuclear Information System (INIS)

    Keller, L.C.

    1981-01-01

    The phenomenon of radiation resistance was studied using micrococci and Moraxella-Acinetobacter capable of surviving very high doses of gamma radiation which were isolated from foods. Physiological age, or growth phase, was found to be an important factor in making comparisons of radiation-resistance among different bacteria and their mutants. Radiation-resistant bacteria were highly resistant to the lethal effect of nitrosoguanidine used for mutagenesis. Studies of relative resistance of radiation-resistant bacteria, radiation-sensitive mutants, and nonradiation-resistant bacteria to killing by different chemical mutagens did not reveal a correlation between the traits of radiation resistance and mutagen resistance among different strains. Comparisons of plasmid profiles of radiation-resistant bacteria and selected radiation-sensitive mutants suggested the possibility that plasmids may carry genes involved in radiation resistance

  14. Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

    Science.gov (United States)

    Vicente, Claudia S. L.; Nascimento, Francisco; Espada, Margarida; Barbosa, Pedro; Mota, Manuel; Glick, Bernard R.; Oliveira, Solange

    2012-01-01

    Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD. PMID:23091599

  15. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 from HT-29 cells · Lactobacillus GG prevents the IL-8 release in response to pathogens · Effect of probiotic bacteria on chemokine response of epithelia to pathogens · PCR array studies in colon ...

  16. Programmed survival of soil bacteria

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Molin, Søren; Sternberg, Claus

    Biological containment systems have been developed for Pseudomonas putida and related soil bacteria. The systems are based on combinations of lethal genes and regulated gene expression. Two types of killing function have been employed: 1) A membrane protein interfering with the membrane potential...

  17. Plant-associated bacteria and their role in the success or failure of metal phytoextraction projects: first observations of a field-related experiment

    Science.gov (United States)

    Weyens, Nele; Beckers, Bram; Schellingen, Kerim; Ceulemans, Reinhart; Croes, Sarah; Janssen, Jolien; Haenen, Stefan; Witters, Nele; Vangronsveld, Jaco

    2013-01-01

    Phytoextraction has been reported as an economically and ecologically sound alternative for the remediation of metal-contaminated soils. Willow is a metal phytoextractor of interest because it allows to combine a gradual contaminant removal with production of biomass that can be valorized in different ways. In this work two willow clones growing on a metal-contaminated site were selected: ‘Belgisch Rood’ (BR) with a moderate metal extraction capacity and ‘Tora’ (TO) with a twice as high metal accumulation. All cultivable bacteria associated with both willow clones were isolated and identified using 16SrDNA ARDRA analysis followed by 16SrDNA sequencing. Further all isolated bacteria were investigated for characteristics that might promote plant growth (production of siderophores, organic acids and indol acetic acid) and for their metal resistance. The genotypic and phenotypic characterization of the isolated bacteria showed that the TO endophytic bacterial population is more diverse and contains a higher percentage of metal-resistant plant growth promoting bacteria than the endophytic population associated with BR. We hypothesize that the difference in the metal accumulation capacity between BR and TO clones might be at least partly related to differences in characteristics of their associated bacterial population. PMID:23425076

  18. The prevalence and control of Bacillus and related spore-forming bacteria in the dairy industry

    Directory of Open Access Journals (Sweden)

    Nidhi eGopal

    2015-12-01

    Full Text Available Milk produced in udder cells is sterile but due to its high nutrient content, it can be a good growth substrate for contaminating bacteria. The quality of milk is monitored via somatic cell counts and total bacterial counts, with prescribed regulatory limits to ensure quality and safety. Bacterial contaminants can cause disease, or spoilage of milk and its secondary products. Aerobic spore-forming bacteria, such as those from the genera Sporosarcina, Paenisporosarcina, Brevibacillus, Paenibacillus, Geobacillus and Bacillus, are a particular concern in this regard as they are able to survive industrial pasteurisation and form biofilms within pipes and stainless steel equipment. These single or multiple-species biofilms become a reservoir of spoilage microorganisms and a cycle of contamination can be initiated. Indeed, previous studies have highlighted that these microorganisms are highly prevalent in dead ends, corners, cracks, crevices, gaskets, valves and the joints of stainless steel equipment used in the dairy manufacturing plants. Hence, adequate monitoring and control measures are essential to prevent spoilage and ensure consumer safety. Common controlling approaches include specific cleaning-in-place processes, chemical and biological biocides and other novel methods. In this review, we highlight the problems caused by these microorganisms, and discuss issues relating to their prevalence, monitoring thereof and control with respect to the dairy industry.

  19. Combined antioxidant effects of Neem extract, bacteria, red blood cells and Lysozyme: possible relation to periodontal disease.

    Science.gov (United States)

    Heyman, Leali; Houri-Haddad, Yael; Heyman, Samuel N; Ginsburg, Isaac; Gleitman, Yossi; Feuerstein, Osnat

    2017-08-10

    The common usage of chewing sticks prepared from Neem tree (Azadirachta indica) in India suggests its potential efficacy in periodontal diseases. The objective of this study is to explore the antibacterial effects of Neem leaf extract on the periodontophatic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum, and its antioxidant capacities alone and in combination with bacteria and polycationic peptides that may be at the site of inflammation. Neem leaf extract was prepared by ethanol extraction. The growth kinetics of P. gingivalis and F. nucleatum under anaerobic conditions in the presence of Neem leaf extract were measured. Broth microdilution test was used to determine the Minimal Inhibitory Concentration (MIC) of Neem leaf extract against each bacterial strain. The effect of Neem leaf extract on the coaggregation of the bacteria was assessed by a visual semi-quantitative assay. The antioxidant capacities of Neem leaf extract alone and in combination with bacteria, with the addition of red blood cells or the polycationic peptides chlorhexidine and lisozyme, were determined using a chemiluminescence assay. Neem leaf extract showed prominent dose-dependent antibacterial activity against P. gingivalis, however, had no effect on the growth of F. nucleatum nor on the coaggregation of the two bacteria. Yet, it showed intense antioxidant activity, which was amplified following adherence to bacteria and with the addition of red blood cells or the polycationic peptides. Neem leaf extract, containing polyphenols that adhere to oral surfaces, have the potential to provide long-lasting antibacterial as well as synergic antioxidant activities when in complex with bacteria, red blood cells and lisozyme. Thus, it might be especially effective in periodontal diseases.

  20. Functional Comparison of Bacteria from the Human Gut and Closely Related Non-Gut Bacteria Reveals the Importance of Conjugation and a Paucity of Motility and Chemotaxis Functions in the Gut Environment.

    Science.gov (United States)

    Dobrijevic, Dragana; Abraham, Anne-Laure; Jamet, Alexandre; Maguin, Emmanuelle; van de Guchte, Maarten

    2016-01-01

    The human GI tract is a complex and still poorly understood environment, inhabited by one of the densest microbial communities on earth. The gut microbiota is shaped by millennia of evolution to co-exist with the host in commensal or symbiotic relationships. Members of the gut microbiota perform specific molecular functions important in the human gut environment. This can be illustrated by the presence of a highly expanded repertoire of proteins involved in carbohydrate metabolism, in phase with the large diversity of polysaccharides originating from the diet or from the host itself that can be encountered in this environment. In order to identify other bacterial functions that are important in the human gut environment, we investigated the distribution of functional groups of proteins in a group of human gut bacteria and their close non-gut relatives. Complementary to earlier global comparisons between different ecosystems, this approach should allow a closer focus on a group of functions directly related to the gut environment while avoiding functions related to taxonomically divergent microbiota composition, which may or may not be relevant for gut homeostasis. We identified several functions that are overrepresented in the human gut bacteria which had not been recognized in a global approach. The observed under-representation of certain other functions may be equally important for gut homeostasis. Together, these analyses provide us with new information about this environment so critical to our health and well-being.

  1. Functional Comparison of Bacteria from the Human Gut and Closely Related Non-Gut Bacteria Reveals the Importance of Conjugation and a Paucity of Motility and Chemotaxis Functions in the Gut Environment.

    Directory of Open Access Journals (Sweden)

    Dragana Dobrijevic

    Full Text Available The human GI tract is a complex and still poorly understood environment, inhabited by one of the densest microbial communities on earth. The gut microbiota is shaped by millennia of evolution to co-exist with the host in commensal or symbiotic relationships. Members of the gut microbiota perform specific molecular functions important in the human gut environment. This can be illustrated by the presence of a highly expanded repertoire of proteins involved in carbohydrate metabolism, in phase with the large diversity of polysaccharides originating from the diet or from the host itself that can be encountered in this environment. In order to identify other bacterial functions that are important in the human gut environment, we investigated the distribution of functional groups of proteins in a group of human gut bacteria and their close non-gut relatives. Complementary to earlier global comparisons between different ecosystems, this approach should allow a closer focus on a group of functions directly related to the gut environment while avoiding functions related to taxonomically divergent microbiota composition, which may or may not be relevant for gut homeostasis. We identified several functions that are overrepresented in the human gut bacteria which had not been recognized in a global approach. The observed under-representation of certain other functions may be equally important for gut homeostasis. Together, these analyses provide us with new information about this environment so critical to our health and well-being.

  2. Method of Detecting Coliform Bacteria from Reflected Light

    Science.gov (United States)

    Vincent, Robert K. (Inventor)

    2014-01-01

    The present invention relates to a method of detecting coliform bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  3. Stability of Dry Probiotic Bacteria in Relation to the Cellular Membrane and Genomic DNA

    DEFF Research Database (Denmark)

    Hansen, Marie-Louise Rittermann W

    powders to infant formula and functional foods, e.g. cereal and chocolate bars. Part of production of the probiotic product often includes freeze-drying of the probiotic bacteria. Drying is necessary in the preparation of dry powders, and to increase shelf life of the product at ambient temperatures....... Freeze-drying and storage of probiotic bacteria can, however, also have a negative effect on cell stability. It is important to understand the processes, which can lead to loss of cell stability during dry storage in order to develop more stable probiotic products. The purpose of the present PhD thesis...

  4. Inhibitory effect of bacteriocin-producing lactic acid bacteria against histamine-forming bacteria isolated from Myeolchi-jeot

    Directory of Open Access Journals (Sweden)

    Eun-Seo Lim

    2016-12-01

    Full Text Available Abstract The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0–8.0 and heating for 10 min at 80 °C; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, α-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.

  5. An ancient divergence among the bacteria. [methanogenic phylogeny

    Science.gov (United States)

    Balch, W. E.; Magrum, L. J.; Fox, G. E.; Wolfe, R. S.; Woese, C. R.

    1977-01-01

    The 16S ribosomal RNZs from two species of met methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to 'typical' Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected - antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

  6. Anaerobic bacteria in the gut of terrestrial isopod Crustacean Porcellio scaber.

    Science.gov (United States)

    Kostanjsek, R; Lapanje, A; Rupnik, M; Strus, J; Drobne, D; Avgustin, G

    2004-01-01

    Anaerobic bacteria from Porcellio scaber hindgut were identified and, subsequently, isolated using molecular approach. Phylogenetic affiliation of bacteria associated with the hindgut wall was determined by analysis of bacterial 16S rRNA gene sequences which were retrieved directly from washed hindguts of P. scaber. Sequences from bacteria related to obligate anaerobic bacteria from genera Bacteroides and Enterococcus were retrieved, as well as sequences from 'A1 subcluster' of the wall-less mollicutes. Bacteria from the genus Desulfotomaculum were isolated from gut wall and cultivated under anaerobic conditions. In contrast to previous reports which suggested the absence of anaerobic bacteria in the isopod digestive system due to short retention time of the food in the tube-like hindgut, frequent renewal of the gut cuticle during the moulting process, and unsuccessful attempts to isolate anaerobic bacteria from this environment our results indicate the presence of resident anaerobic bacteria in the gut of P. scaber, in spite of apparently unsuitable, i.e. predominantly oxic, conditions.

  7. Correlation of Metabolic Variables with the Number of ORFs in Human Pathogenic and Phylogenetically Related Non- or Less-Pathogenic Bacteria.

    Science.gov (United States)

    Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Garcia-Guevara, Jose Fernando; Rodríguez-Vázquez, Katya

    2016-06-01

    To date, a few works have performed a correlation of metabolic variables in bacteria; however specific correlations with these variables have not been reported. In this work, we included 36 human pathogenic bacteria and 18 non- or less-pathogenic-related bacteria and obtained all metabolic variables, including enzymes, metabolic pathways, enzymatic steps and specific metabolic pathways, and enzymatic steps of particular metabolic processes, from a reliable metabolic database (KEGG). Then, we correlated the number of the open reading frames (ORF) with these variables and with the proportions of these variables, and we observed a negative correlation with the proportion of enzymes (r = -0.506, p < 0.0001), metabolic pathways (r = -0.871, p < 00.0001), enzymatic reactions (r = -0.749, p < 00.0001), and with the proportions of central metabolism variables as well as a positive correlation with the proportions of multistep reactions (r = 0.650, p < 00.0001) and secondary metabolism variables. The proportion of multifunctional reactions (r: -0.114, p = 0.41) and the proportion of enzymatic steps (r: -0.205, p = 0.14) did not present a significant correlation. These correlations indicate that as the size of a genome (measured in the number of ORFs) increases, the proportion of genes that encode enzymes significantly diminishes (especially those related to central metabolism), suggesting that when essential metabolic pathways are complete, an increase in the number of ORFs does not require a similar increase in the metabolic pathways and enzymes, but only a slight increase is sufficient to cope with a large genome.

  8. Selection of local extremophile lactic acid bacteria with high capacity ...

    African Journals Online (AJOL)

    This study is related to the isolation and identification of strains of local thermophilic lactic acid bacteria belonging to the species, Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria can exist under extreme conditions of the digestive tract (acidity and high concentration of bile salts) and have a high ...

  9. Targeted photodynamic therapy of established soft-tissue infections in mice

    Science.gov (United States)

    Gad, Faten; Zahra, Touqir; Hasan, Tayyaba; Hamblin, Michael R.

    2004-06-01

    The worldwide rise in antibiotic resistance necessitates the development of novel antimicrobial strategies. Although many workers have used photodynamic therapy (PDT) to kill bacteria in vitro, the use of this approach has seldom been reported in vivo in animal models of infection. We have previously described the first use of PDT to treat excisional wound infections by Gram-negative bacteria in living mice. However these infected wound models used a short time after infection (30 min) before PDT. We now report on the use of PDT to treat an established soft-tissue infection in mice. We used Staphylococcus aureus stably transformed with a Photorhabdus luminescens lux operon (luxABCDE) that was genetically modified to be functional in Gram-positive bacteria. These engineered bacteria emitted bioluminescence allowing the progress of the infection to be monitored in both space and time with a lowlight imaging charged couple device (CCD) camera. One million cells were injected into one or both thigh muscles of mice that had previously been rendered neutropenic by cyclophosphamide administration. Twenty-four hours later the bacteria had multiplied more than one hundred-fold, and poly-L-lysine chlorin(e6) conjugate or free chlorin(e6) was injected into one area of infected muscle and imaged with the CCD camera. Thirty-minutes later red light from a diode laser was delivered as a surface spot or by interstitial fiber into the infection. There was a lightdose dependent loss of bioluminescence (to resistant soft-tissue infections.

  10. Diversity, abundance, and possible sources of fecal bacteria in the Yangtze River.

    Science.gov (United States)

    Sun, Haohao; He, Xiwei; Ye, Lin; Zhang, Xu-Xiang; Wu, Bing; Ren, Hongqiang

    2017-03-01

    The fecal bacteria in natural waters may pose serious risks on human health. Although many source tracking methods have been developed and used to determine the possible sources of the fecal pollution, little is known about the overall diversity and abundance of fecal bacterial community in natural waters. In this study, a method based on fecal bacterial sequence library was introduced to evaluate the fecal bacterial profile in the Yangtze River (Nanjing section). Our results suggested that the Yangtze River water harbors diverse fecal bacteria. Fifty-eight fecal operational taxonomic units (97% identity level) were detected in the Yangtze River water samples and the relative abundance of fecal bacteria in these samples ranged from 0.1 to 8%. It was also found that the relative abundances of the fecal bacteria in locations near to the downstream of wastewater treatment plants were obviously higher than those in other locations. However, the high abundance of fecal bacteria could decrease to the normal level in 2~4 km in the river due to degradation or dilution, and the overall fecal bacteria level changed little when the Yangtze River flew through the Nanjing City. Moreover, the fecal bacteria in the Yangtze River water were found to be highly associated (Spearman rho = 0.804, P Yangtze River and advance our understandings of the fecal bacteria community in the natural waters.

  11. Low Prevalence of Carbapenem-Resistant Bacteria in River Water: Resistance Is Mostly Related to Intrinsic Mechanisms.

    Science.gov (United States)

    Tacão, Marta; Correia, António; Henriques, Isabel S

    2015-10-01

    Carbapenems are last-resort antibiotics to handle serious infections caused by multiresistant bacteria. The incidence of resistance to these antibiotics has been increasing and new resistance mechanisms have emerged. The dissemination of carbapenem resistance in the environment has been overlooked. The main goal of this research was to assess the prevalence and diversity of carbapenem-resistant bacteria in riverine ecosystems. The presence of frequently reported carbapenemase-encoding genes was inspected. The proportion of imipenem-resistant bacteria was on average 2.24 CFU/ml. Imipenem-resistant strains (n=110) were identified as Pseudomonas spp., Stenotrophomonas maltophilia, Aeromonas spp., Chromobacterium haemolyticum, Shewanella xiamenensis, and members of Enterobacteriaceae. Carbapenem-resistant bacteria were highly resistant to other beta-lactams such as quinolones, aminoglycosides, chloramphenicol, tetracyclines, and sulfamethoxazole/trimethoprim. Carbapenem resistance was mostly associated with intrinsically resistant bacteria. As intrinsic resistance mechanisms, we have identified the blaCphA gene in 77.3% of Aeromonas spp., blaL1 in all S. maltophilia, and blaOXA-48-like in all S. xiamenensis. As acquired resistance mechanisms, we have detected the blaVIM-2 gene in six Pseudomonas spp. (5.45%). Integrons with gene cassettes encoding resistance to aminoglycosides (aacA and aacC genes), trimethoprim (dfrB1b), and carbapenems (blaVIM-2) were found in Pseudomonas spp. Results suggest that carbapenem resistance dissemination in riverine ecosystems is still at an early stage. Nevertheless, monitoring these aquatic compartments for the presence of resistance genes and its host organisms is essential to outline strategies to minimize resistance dissemination.

  12. Like will to like: abundances of closely related species can predict susceptibility to intestinal colonization by pathogenic and commensal bacteria.

    Science.gov (United States)

    Stecher, Bärbel; Chaffron, Samuel; Käppeli, Rina; Hapfelmeier, Siegfried; Freedrich, Susanne; Weber, Thomas C; Kirundi, Jorum; Suar, Mrutyunjay; McCoy, Kathy D; von Mering, Christian; Macpherson, Andrew J; Hardt, Wolf-Dietrich

    2010-01-01

    The intestinal ecosystem is formed by a complex, yet highly characteristic microbial community. The parameters defining whether this community permits invasion of a new bacterial species are unclear. In particular, inhibition of enteropathogen infection by the gut microbiota ( = colonization resistance) is poorly understood. To analyze the mechanisms of microbiota-mediated protection from Salmonella enterica induced enterocolitis, we used a mouse infection model and large scale high-throughput pyrosequencing. In contrast to conventional mice (CON), mice with a gut microbiota of low complexity (LCM) were highly susceptible to S. enterica induced colonization and enterocolitis. Colonization resistance was partially restored in LCM-animals by co-housing with conventional mice for 21 days (LCM(con21)). 16S rRNA sequence analysis comparing LCM, LCM(con21) and CON gut microbiota revealed that gut microbiota complexity increased upon conventionalization and correlated with increased resistance to S. enterica infection. Comparative microbiota analysis of mice with varying degrees of colonization resistance allowed us to identify intestinal ecosystem characteristics associated with susceptibility to S. enterica infection. Moreover, this system enabled us to gain further insights into the general principles of gut ecosystem invasion by non-pathogenic, commensal bacteria. Mice harboring high commensal E. coli densities were more susceptible to S. enterica induced gut inflammation. Similarly, mice with high titers of Lactobacilli were more efficiently colonized by a commensal Lactobacillus reuteri(RR) strain after oral inoculation. Upon examination of 16S rRNA sequence data from 9 CON mice we found that closely related phylotypes generally display significantly correlated abundances (co-occurrence), more so than distantly related phylotypes. Thus, in essence, the presence of closely related species can increase the chance of invasion of newly incoming species into the gut

  13. SOME STATISTICAL ISSUES RELATED TO MULTIPLE LINEAR REGRESSION MODELING OF BEACH BACTERIA CONCENTRATIONS

    Science.gov (United States)

    As a fast and effective technique, the multiple linear regression (MLR) method has been widely used in modeling and prediction of beach bacteria concentrations. Among previous works on this subject, however, several issues were insufficiently or inconsistently addressed. Those is...

  14. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  15. Relative abundance of total subgingival plaque-specific bacteria in salivary microbiota reflects the overall periodontal condition in patients with periodontitis.

    Science.gov (United States)

    Kageyama, Shinya; Takeshita, Toru; Asakawa, Mikari; Shibata, Yukie; Takeuchi, Kenji; Yamanaka, Wataru; Yamashita, Yoshihisa

    2017-01-01

    Increasing attention is being focused on evaluating the salivary microbiota as a promising method for monitoring oral health; however, its bacterial composition greatly differs from that of dental plaque microbiota, which is a dominant etiologic factor of oral diseases. This study evaluated the relative abundance of subgingival plaque-specific bacteria in the salivary microbiota and examined a relationship between the abundance and severity of periodontal condition in patients with periodontitis. Four samples (subgingival and supragingival plaques, saliva, and tongue coating) per each subject were collected from 14 patients with a broad range of severity of periodontitis before periodontal therapy. The bacterial composition was analyzed by 16S rRNA gene amplicon sequencing using Ion PGM. Of the 66 species-level operational taxonomic units (OTUs) representing the mean relative abundance of ≥ 1% in any of the four niches, 12 OTUs corresponding to known periodontal pathogens, including Porphyromonas gingivalis, were characteristically predominant in the subgingival plaque and constituted 37.3 ± 22.9% of the microbiota. The total relative abundance of these OTUs occupied only 1.6 ± 1.2% of the salivary microbiota, but significantly correlated with the percentage of diseased sites (periodontal pocket depth ≥ 4 mm; r = 0.78, P periodontal therapy, the total relative abundance of these 12 OTUs was evaluated as well as before periodontal therapy and reductions of the abundance through periodontal therapy were strongly correlated in saliva and subgingival plaque (r = 0.81, P bacteria representing the present condition of periodontal health.

  16. CRISPR-Cas Technologies and Applications in Food Bacteria.

    Science.gov (United States)

    Stout, Emily; Klaenhammer, Todd; Barrangou, Rodolphe

    2017-02-28

    Clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins form adaptive immune systems that occur in many bacteria and most archaea. In addition to protecting bacteria from phages and other invasive mobile genetic elements, CRISPR-Cas molecular machines can be repurposed as tool kits for applications relevant to the food industry. A primary concern of the food industry has long been the proper management of food-related bacteria, with a focus on both enhancing the outcomes of beneficial microorganisms such as starter cultures and probiotics and limiting the presence of detrimental organisms such as pathogens and spoilage microorganisms. This review introduces CRISPR-Cas as a novel set of technologies to manage food bacteria and offers insights into CRISPR-Cas biology. It primarily focuses on the applications of CRISPR-Cas systems and tools in starter cultures and probiotics, encompassing strain-typing, phage resistance, plasmid vaccination, genome editing, and antimicrobial activity.

  17. Characterization and PCR Detection Of Binary, Pir-Like Toxins from Vibrio parahaemolyticus Isolates that Cause Acute Hepatopancreatic Necrosis Disease (AHPND in Shrimp.

    Directory of Open Access Journals (Sweden)

    Ratchanok Sirikharin

    Full Text Available Unique isolates of Vibrio parahaemolyticus (VPAHPND have previously been identified as the causative agent of acute hepatopancreatic necrosis disease (AHPND in shrimp. AHPND is characterized by massive sloughing of tubule epithelial cells of the hepatopancreas (HP, proposed to be induced by soluble toxins released from VPAHPND that colonize the shrimp stomach. Since these toxins (produced in broth culture have been reported to cause AHPND pathology in reverse gavage bioassays with shrimp, we used ammonium sulfate precipitation to prepare protein fractions from broth cultures of VPAHPND isolates for screening by reverse gavage assays. The dialyzed 60% ammonium sulfate fraction caused high mortality within 24-48 hours post-administration, and histological analysis of the moribund shrimp showed typical massive sloughing of hepatopancreatic tubule epithelial cells characteristic of AHPND. Analysis of the active fraction by SDS-PAGE revealed two major bands at marker levels of approximately 16 kDa (ToxA and 50 kDa (ToxB. Mass spectrometry analysis followed by MASCOT analysis revealed that both proteins had similarity to hypothetical proteins of V. parahaemolyticus M0605 (contig034 GenBank accession no. JALL01000066.1 and similarity to known binary insecticidal toxins called 'Photorhabdus insect related' proteins A and B (Pir-A and Pir-B, respectively, produced by the symbiotic, nematode bacterium Photorhabdus luminescens. In in vivo tests, it was shown that recombinant ToxA and ToxB were both required in a dose dependent manner to cause AHPND pathology, indicating further similarity to Pir-A and -B. A single-step PCR method was designed for detection of the ToxA gene and was validated using 104 bacterial isolates consisting of 51 VPAHPND isolates, 34 non-AHPND VP isolates and 19 other isolates of bacteria commonly found in shrimp ponds (including other species of Vibrio and Photobacterium. The results showed 100% specificity and sensitivity for

  18. A flow cytometric technique for quantification and differentiation of bacteria in bulk tank milk

    DEFF Research Database (Denmark)

    Holm, C.; Mathiasen, T.; Jespersen, Lene

    2004-01-01

    were defined: region 1 includes bacteria mainly associated with poor hygiene, region 2 includes psychrotrophic hygiene bacteria and region 3 includes bacteria mainly related to mastitis. The ability of the flow cytometric technique to predict the main cause of elevated bacterial counts on routine...

  19. Prevalence of pathogenic bacteria in Ixodes ricinus ticks in Central Bohemia.

    Science.gov (United States)

    Klubal, Radek; Kopecky, Jan; Nesvorna, Marta; Sparagano, Olivier A E; Thomayerova, Jana; Hubert, Jan

    2016-01-01

    Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries.

  20. AIDS: "it's the bacteria, stupid!".

    Science.gov (United States)

    Broxmeyer, Lawrence; Cantwell, Alan

    2008-11-01

    Acid-fast tuberculous mycobacterial infections are common in AIDS and are regarded as secondary "opportunistic infections." According to the National Institute of Allergy and Infectious Diseases, TB is the major attributable cause of death in AIDS patients. Could such bacteria play a primary or causative role in AIDS? Certainly, In screening tests for HIV, there is frequent, up to 70%, cross-reactivity, between the gag and pol proteins of HIV and patients with mycobacterial infections such as tuberculosis. By 1972, five years before gays started dying in the U.S., Rolland wrote Genital Tuberculosis, a Forgotten Disease? And ironically, in 1979, on the eve of AIDS recognition, Gondzik and Jasiewicz showed that even in the laboratory, genitally infected tubercular male guinea pigs could infect healthy females through their semen by an HIV-compatible ratio of 1 in 6 or 17%, prompting him to warn his patients that not only was tuberculosis a sexually transmitted disease, but also the necessity of the application of suitable contraceptives, such as condoms, to avoid it. Gondzik's solution and date of publication are chilling; his findings significant. Since 1982 Cantwell et al found acid-fast bacteria closely related to tuberculosis (TB) and atypical tuberculosis in AIDS tissue. On the other hand molecular biologist and virologist Duesberg, who originally defined retroviral ultrastructure, has made it clear that HIV is not the cause of AIDS and that the so-called AIDS retrovirus has never been isolated in its pure state. Dr. Etienne de Harven, first to examine retroviruses under the electron, agrees. In 1993 HIV co-discoverer Luc Montagnier reported on cell-wall-deficient (CWD) bacteria which he called "mycoplasma" in AIDS tissue. He suspected these as a necessary "co-factor" for AIDS. Remarkably, Montagnier remained silent on Cantwell's reports of acid-fast bacteria which could simulate "mycoplasma" in AIDS tissue. Mattman makes clear that the differentiation between

  1. The aerobic activity of metronidazole against anaerobic bacteria.

    Science.gov (United States)

    Dione, Niokhor; Khelaifia, Saber; Lagier, Jean-Christophe; Raoult, Didier

    2015-05-01

    Recently, the aerobic growth of strictly anaerobic bacteria was demonstrated using antioxidants. Metronidazole is frequently used to treat infections caused by anaerobic bacteria; however, to date its antibacterial activity was only tested in anaerobic conditions. Here we aerobically tested using antioxidants the in vitro activities of metronidazole, gentamicin, doxycycline and imipenem against 10 common anaerobic and aerobic bacteria. In vitro susceptibility testing was performed by the disk diffusion method, and minimum inhibitory concentrations (MICs) were determined by Etest. Aerobic culture of the bacteria was performed at 37°C using Schaedler agar medium supplemented with 1mg/mL ascorbic acid and 0.1mg/mL glutathione; the pH was adjusted to 7.2 by 10M KOH. Growth of anaerobic bacteria cultured aerobically using antioxidants was inhibited by metronidazole after 72h of incubation at 37°C, with a mean inhibition diameter of 37.76mm and an MIC of 1μg/mL; however, strains remained non-sensitive to gentamicin. No growth inhibition of aerobic bacteria was observed after 24h of incubation at 37°C with metronidazole; however, inhibition was observed with doxycycline and imipenem used as controls. These results indicate that bacterial sensitivity to metronidazole is not related to the oxygen tension but is a result of the sensitivity of the micro-organism. In future, both culture and antibiotic susceptibility testing of strictly anaerobic bacteria will be performed in an aerobic atmosphere using antioxidants in clinical microbiology laboratories. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  2. Corrosion of candidate container materials by Yucca Mountain bacteria

    International Nuclear Information System (INIS)

    Horn, J; Jones, D; Lian, T; Martin, S; Rivera, A

    1999-01-01

    Several candidate container materials have been studied in modified Yucca Mountain (YM) ground water in the presence or absence of YM bacteria. YM bacteria increased corrosion rates by 5-6 fold in UNS G10200 carbon steel, and nearly 100-fold in UNS NO4400 Ni-Cu alloy. YM bacteria caused microbiologically influenced corrosion (MIC) through de-alloying or Ni-depletion of Ni-Cu alloy as evidenced by scanning electronic microscopy (SEM) and inductively coupled plasma spectroscopy (ICP) analysis. MIC rates of more corrosion-resistant alloys such as UNS NO6022 Ni-Cr- MO-W alloy, UN's NO6625 Ni-Cr-Mo alloy, and UNS S30400 stainless steel were measured below 0.05 umyr, however YM bacteria affected depletion of Cr and Fe relative to Ni in these materials. The chemical change on the metal surface caused by depletion was characterized in anodic polarization behavior. The anodic polarization behavior of depleted Ni-based alloys was similar to that of pure Ni. Key words: MIC, container materials, YM bacteria, de-alloying, Ni-depletion, Cr-depletion, polarization resistance, anodic polarization,

  3. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  4. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

    OpenAIRE

    Denoncourt, Alix M.; Paquet, Valérie E.; Charette, Steve J.

    2014-01-01

    Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging...

  5. Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

    International Nuclear Information System (INIS)

    Malkin, A.J.

    2010-01-01

    The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

  6. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available oduct ... [Photorhabdus luminescens subsp. laumondii TTO1] ... Length = 218 ... Query: 87 ... LEQKMTTDIPSAS...LTQKGVVQLTNVVGNSDTLAVTQKLVQEVINSLREYTREEIDNRMKT 146 ... LEQKMTTDIPSAS...LTQKGVVQLTNVVGNSDTLAVTQKLVQEVINSLREYTREEIDNRMKT Sbjct: 1 ... LEQKMTTDIPSASLTQKGVVQLTNVVGNSDTLAVTQKLVQEVINSLR

  7. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available oduct ... [Photorhabdus luminescens subsp. laumondii TTO1] ... Length = 185 ... Query: 87 ... LEQKITTDIPSAS...LTQKGVVQLTNVMGNSDTLAVTQKLVQEVINALRADITIPVGSPIPW 146 ... LEQKITTDIPSAS...LTQKGVVQLTNVMGNSDTLAVTQKLVQEVINALRADITIPVGSPIPW Sbjct: 1 ... LEQKITTDIPSASLTQKGVVQLTNVMGNSDTLAVTQKLVQEVINALR

  8. Evolution of the Kdo2-lipid A Biosynthesis in Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    S Opiyo; R Pardy; H Moriyama; E Moriyama

    2011-12-31

    BACKGROUND: Lipid A is the highly immunoreactive endotoxic center of lipopolysaccharide (LPS). It anchors the LPS into the outer membrane of most Gram-negative bacteria. Lipid A can be recognized by animal cells, triggers defense-related responses, and causes Gram-negative sepsis. The biosynthesis of Kdo2-lipid A, the LPS substructure, involves with nine enzymatic steps. RESULTS: In order to elucidate the evolutionary pathway of Kdo2-lipid A biosynthesis, we examined the distribution of genes encoding the nine enzymes across bacteria. We found that not all Gram-negative bacteria have all nine enzymes. Some Gram-negative bacteria have no genes encoding these enzymes and others have genes only for the first four enzymes (LpxA, LpxC, LpxD, and LpxB). Among the nine enzymes, five appeared to have arisen from three independent gene duplication events. Two of such events happened within the Proteobacteria lineage, followed by functional specialization of the duplicated genes and pathway optimization in these bacteria. CONCLUSIONS: The nine-enzyme pathway, which was established based on the studies mainly in Escherichia coli K12, appears to be the most derived and optimized form. It is found only in E. coli and related Proteobacteria. Simpler and probably less efficient pathways are found in other bacterial groups, with Kdo2-lipid A variants as the likely end products. The Kdo2-lipid A biosynthetic pathway exemplifies extremely plastic evolution of bacterial genomes, especially those of Proteobacteria, and how these mainly pathogenic bacteria have adapted to their environment.

  9. More, smaller bacteria in response to ocean's warming?

    KAUST Repository

    Moran, Xose Anxelu G.

    2015-06-10

    Heterotrophic bacteria play a major role in organic matter cycling in the ocean. Although the high abundances and relatively fast growth rates of coastal surface bacterioplankton make them suitable sentinels of global change, past analyses have largely overlooked this functional group. Here, time series analysis of a decade of monthly observations in temperate Atlantic coastal waters revealed strong seasonal patterns in the abundance, size and biomass of the ubiquitous flow-cytometric groups of low (LNA) and high nucleic acid (HNA) content bacteria. Over this relatively short period, we also found that bacterioplankton cells were significantly smaller, a trend that is consistent with the hypothesized temperature-driven decrease in body size. Although decadal cell shrinking was observed for both groups, it was only LNA cells that were strongly coherent, with ecological theories linking temperature, abundance and individual size on both the seasonal and interannual scale. We explain this finding because, relative to their HNA counterparts, marine LNA bacteria are less diverse, dominated by members of the SAR11 clade. Temperature manipulation experiments in 2012 confirmed a direct effect of warming on bacterial size. Concurrent with rising temperatures in spring, significant decadal trends of increasing standing stocks (3% per year) accompanied by decreasing mean cell size (-1% per year) suggest a major shift in community structure, with a larger contribution of LNA bacteria to total biomass. The increasing prevalence of these typically oligotrophic taxa may severely impact marine foodwebs and carbon fluxes by an overall decrease in the efficiency of the biological pump. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  10. Grazing of particle-associated bacteria-an elimination of the non-viable fraction.

    Science.gov (United States)

    Gonsalves, Maria-Judith; Fernandes, Sheryl Oliveira; Priya, Madasamy Lakshmi; LokaBharathi, Ponnapakkam Adikesavan

    Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42h showed that at the end of 24h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, 'k' value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g)=0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, 'g' of non-viable fraction (particle-associated bacteria=0.615, Free=0.0086) was much greater than the viable fraction (particle-associated bacteria=0.056, Free=0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the "persistent variants" where the viable fraction multiply and release their progeny. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  11. Grazing of particle-associated bacteria-an elimination of the non-viable fraction

    Directory of Open Access Journals (Sweden)

    Maria-Judith Gonsalves

    Full Text Available Abstract Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ‘k’ value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g = 0.564, the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, ‘g’ of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086 was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068. Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the “persistent variants” where the viable fraction multiply and release their progeny.

  12. Anaerobic Ammonium-Oxidizing Bacteria in Cow Manure Composting.

    Science.gov (United States)

    Wang, Tingting; Cheng, Lijun; Zhang, Wenhao; Xu, Xiuhong; Meng, Qingxin; Sun, Xuewei; Liu, Huajing; Li, Hongtao; Sun, Yu

    2017-07-28

    Composting is widely used to transform waste into valuable agricultural organic fertilizer. Anaerobic ammonium-oxidizing (anammox) bacteria play an important role in the global nitrogen cycle, but their role in composting remains poorly understood. In the present study, the community structure, diversity, and abundance of anammox bacteria were analyzed using cloning and sequencing methods by targeting the 16S rRNA gene and the hydrazine oxidase gene ( hzo ) in samples isolated from compost produced from cow manure and rice straw. A total of 25 operational taxonomic units were classified based on 16S rRNA gene clone libraries, and 14 operational taxonomic units were classified based on hzo gene clone libraries. The phylogenetic tree analysis of the 16S rRNA gene and deduced HZO protein sequences from the corresponding encoding genes indicated that the majority of the obtained clones were related to the known anammox bacteria Candidatus "Brocadia," Candidatus "Kuenenia," and Candidatus "Scalindua." The abundances of anammox bacteria were determined by quantitative PCR, and between 2.13 × 10 5 and 1.15 × 10 6 16S rRNA gene copies per gram of compost were found. This study provides the first demonstration of the existence of anammox bacteria with limited diversity in cow manure composting.

  13. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  14. Survival of heterotrophic bacteria in water environment under substrate deficiency

    International Nuclear Information System (INIS)

    Toth, D.

    1989-01-01

    The relationship between metabolic changes and survival of bacteria in the water environment under substrate deficiency was studied. The main factors supporting cell survival were cryptic growth, utilization of endogenous reserve substances and reorganization of metabolic activities. Based on the utilization of cell-free extract or lysates from dead bacteria, an Enterobacter aerogenes cell suspension yielded 50% more colonies. Metabolic processes of starved heterotrophic bacteria changed markedly and became stabilized at a lower level depending on species involved. The rate of utilization of endogenous reserve substances as indicated by endogenous respiration was related to the rate of cell mortality. Of the test bacteria, Pseudomonas fluorescens showed the lowest rates of endogenous respiration and mortality while in Enterobacter aerogenes these two rates were the highest. (author). 3 figs., 2 tabs.., 16 refs

  15. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available XXXXXXXXXHQIMMDGNAGDKAPSPMEMVLMAAGGCSTIDVVSILHKGRYDI 63 ... RVKWV ... HQIMMDGNAGDKAPSPME...MVLMAAGGCSTIDVVSILHKGRYDI Sbjct: 1 ... RVKWVEGLSLLGESSSGHQIMMDGNAGDKAPSPMEMVLMAAGGCSTIDVV...uct ... [Photorhabdus luminescens subsp. laumondii TTO1] ... Length = 130 ... Query: 4 ... RVKWVXXX

  16. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available oduct ... [Photorhabdus luminescens subsp. laumondii TTO1] ... Length = 104 ... Query: 218 QDLQRWAQANLQGISGLQDMATH...MNLSIRHLGRLFRQELNMKAGVWLEHARIEKARTLLE 277 ... QDLQRWAQANLQGISGLQDMATH...MNLSIRHLGRLFRQELNMKAGVWLEHARIEKARTLLE Sbjct: 1 ... QDLQRWAQANLQGISGLQDMATHMNLSIRHLGRLFRQELNMKAGVWLEHARIEKARTLLE 60 ...

  17. The role of anaerobic bacteria in the cystic fibrosis airway.

    Science.gov (United States)

    Sherrard, Laura J; Bell, Scott C; Tunney, Michael M

    2016-11-01

    Anaerobic bacteria are not only normal commensals, but are also considered opportunistic pathogens and have been identified as persistent members of the lower airway community in people with cystic fibrosis of all ages and stages of disease. Currently, the role of anaerobic bacteria in cystic fibrosis lower airway disease is not well understood. Therefore, this review describes the recent studies relating to the potential pathophysiological role(s) of anaerobes within the cystic fibrosis lungs. The most frequently identified anaerobic bacteria in the lower airways are common to both cystic fibrosis and healthy lungs. Studies have shown that in cystic fibrosis, the relative abundance of anaerobes fluctuates in the lower airways with reduced lung function and increased inflammation associated with a decreased anaerobic load. However, anaerobes found within the lower airways also produce virulence factors, may cause a host inflammatory response and interact synergistically with recognized pathogens. Anaerobic bacteria are potentially members of the airway microbiota in health but could also contribute to the pathogenesis of lower airway disease in cystic fibrosis via both direct and indirect mechanisms. A personalized treatment strategy that maintains a normal microbial community may be possible in the future.

  18. Soil bacteria for remediation of polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Springael, D; Bastiaens, L; Carpels, M; Mergaey, M; Diels, L

    1996-09-18

    Soil bacteria, specifically adapted to contaminated soils, may be used for the remediation of polluted soils. The Flemish research institute VITO has established a collection of bacteria, which were isolated from contaminated areas. This collection includes microbacteria degrading mineral oils (Pseudomonas sp., Acinetobacter sp. and others), microbacteria degrading polycyclic aromatic hydrocarbons (genera Sphingomonas and Mycobacterium), microbacteria degrading polychlorobiphenyls (genus Ralstonia and strains related to beta-Proteobacteria), and metal resistant bacteria with plasmid borne resistances to Cd, Zn, Ni, Co, Cu, Hg, and Cr. Bench-scale reactors were developed to investigate the industrial feasibility of bioremediation. Batch Stirred Tank Reactors were used to evaluate the efficiency of oil degraders. Soils, contaminated with non-ferrous metals, were treated using a Bacterial Metal Slurry Reactor. It was found that the reduction of the Cd concentration may vary strongly from sample to sample: reduction factors vary from 95 to 50%. Is was shown that Cd contained in metallic sinter and biologically unavailable Cd could not be removed.

  19. The Composition of Colonic Commensal Bacteria According to Anatomical Localization in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Liuyang Zhao

    2017-02-01

    Full Text Available Colorectal cancer (CRC is a multistage disease resulting from complex factors, including genetic mutations, epigenetic changes, chronic inflammation, diet, and lifestyle. Recent accumulating evidence suggests that the gut microbiota is a new and important player in the development of CRC. Imbalance of the gut microbiota, especially dysregulated gut bacteria, contributes to colon cancer through mechanisms of inflammation, host defense modulations, oxidative stress, and alterations in bacterial-derived metabolism. Gut commensal bacteria are anatomically defined as four populations: luminal commensal bacteria, mucus-resident bacteria, epithelium-resident bacteria, and lymphoid tissue-resident commensal bacteria. The bacterial flora that are harbored in the gastrointestinal (GI tract vary both longitudinally and cross-sectionally by different anatomical localization. It is notable that the translocation of colonic commensal bacteria is closely related to CRC progression. CRC-associated bacteria can serve as a non-invasive and accurate biomarker for CRC diagnosis. In this review, we summarize recent findings on the oncogenic roles of gut bacteria with different anatomical localization in CRC progression.

  20. Antimicrobial activities of epiphytic bacteria associated of the brown alga Padina pavonica

    Directory of Open Access Journals (Sweden)

    Amel Ben Ali Ismail

    2016-07-01

    Full Text Available Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria, Firmicutes (4 isolates and Actinobacteria (2 isolates. The antimicrobial activity was assessed as inhibition of growth of twelve species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus and one pathogenic yeast (Candida albicans. Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds.

  1. Obtaining Low Rank Coal Biotransforming Bacteria from Microhabitats Enriched with Carbonaceous Residues

    International Nuclear Information System (INIS)

    Valero Valero, Nelson; Rodriguez Salazar, Luz Nidia; Mancilla Gomez, Sandra; Contreras Bayona, Leydis

    2012-01-01

    Bacteria capable of low rank coal (LRC) biotransform were isolated from environmental samples altered with coal in the mine The Cerrejon. A protocol was designed to select strains more capable of LRC biotransform, the protocol includes isolation in a selective medium with LRC powder, qualitative and quantitative tests for LRC solubilization in solid and liquid culture medium. Of 75 bacterial strains isolated, 32 showed growth in minimal salts agar with 5 % carbon. The strains that produce higher values of humic substances (HS) have a mechanism of solubilization associated with pH changes in the culture medium, probably related to the production of extracellular alkaline substances by bacteria. The largest number of strains and bacteria with more solubilizing activity on LRC were isolated from sludge with high content of carbon residue and rhizosphere of Typha domingensis and Cenchrus ciliaris grown on sediments mixed with carbon particles, this result suggests that obtaining and solubilization capacity of LRC by bacteria may be related to the microhabitat where the populations originated.

  2. Investigations of the effect of electron-beam irradiation on bacteria in sewage sludge

    International Nuclear Information System (INIS)

    Osterstock, G.

    1976-01-01

    The effect of electron beams on bacteria was investigated in 2 experimental facilities. A 400 kV electron accelerator was used to irradiate sludge quantities of 10 l and 180 l. The total bacterial count, number of coliform bacteria and, in injected sludge, the relative bacteria density of salmonella were investigated. A dose of 0.5 to 0.75 Mrad was required to reduce coliform bacteria to below the detectable level in 0.1 ml. With a dose of 1.5 Mrad salmonella were reduced by 6 orders of magnitude on the average. In addition, the dependence of the reduction in bacteria on the dose rate as well as on mixing of the irradiation material was investigated. Substantial reproduction of bacteria in digested sludge was found in all cases after the irradiation. (author)

  3. The seaweed holobiont: understanding seaweed-bacteria interactions.

    Science.gov (United States)

    Egan, Suhelen; Harder, Tilmann; Burke, Catherine; Steinberg, Peter; Kjelleberg, Staffan; Thomas, Torsten

    2013-05-01

    Seaweeds (macroalgae) form a diverse and ubiquitous group of photosynthetic organisms that play an essential role in aquatic ecosystems. These ecosystem engineers contribute significantly to global primary production and are the major habitat formers on rocky shores in temperate waters, providing food and shelter for aquatic life. Like other eukaryotic organisms, macroalgae harbor a rich diversity of associated microorganisms with functions related to host health and defense. In particular, epiphytic bacterial communities have been reported as essential for normal morphological development of the algal host, and bacteria with antifouling properties are thought to protect chemically undefended macroalgae from detrimental, secondary colonization by other microscopic and macroscopic epibiota. This tight relationship suggests that macroalgae and epiphytic bacteria interact as a unified functional entity or holobiont, analogous to the previously suggested relationship in corals. Moreover, given that the impact of diseases in marine ecosystems is apparently increasing, understanding the role of bacteria as saprophytes and pathogens in seaweed communities may have important implications for marine management strategies. This review reports on the recent advances in the understanding of macroalgal-bacterial interactions with reference to the diversity and functional role of epiphytic bacteria in maintaining algal health, highlighting the holobiont concept. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  4. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  5. Magnetotactic bacteria in marine sediments: clues from recent cores from Brazilian Coast

    Science.gov (United States)

    Jovane, L.; Pellizari, V. H.; Brandini, F. P.; Braga, E. D. S.; Freitas, G. R.; Benites, M.; Rodelli, D.; Giorgioni, M.; Iacoviello, F.; Ruffato, D. G.; Lins, U.

    2014-12-01

    The magnetic properties (first order reversal curves, ferromagnetic resonance and decomposition of saturation remanent magnetization acquisition) of marine magnetotactic bacteria, in conjunction with geophysical, geochemical and oceanographic data from the Brazilian Coast, provide interesting insights regarding the primary productivity distribution in oceans. This finding suggests that magnetite produced by some magnetotactic bacteria retains magnetic properties in relation to the crystallographic structure of the magnetic phase produced and thus might represent a "magnetic fingerprint" for the presence of magnetotactic bacteria. The use of those magnetic properties is a non-destructive, new technology that might allow for the identification and presence of specific species or types of magnetotactic bacteria in certain environments such as sediment. We will also show some preliminary results on the biogeochemical factors that control magnetotactic bacterial populations, documenting the environment and the preservation of bacterial magnetite, which dominates the palaeomagnetic signal throughout recent sediments from Brazilian Coast. We searched for magnetotactic bacteria in order to understand the ecosystems and environmental change related to their presence in sediments. We studied magnetotactic bacterial concentration and geophysical, geochemical and oceanographic results in marine settings measuring crucially nutrients availability in the water column and in sediments, on particulate delivery to the seafloor, to understand the environmental condition that allow the presence of magnetotactic bacteria and magnetosomes in sediments.

  6. Partial Purification Characterization and Application of Bacteriocin from Bacteria Isolated Parkia biglobosa Seeds

    OpenAIRE

    Olorunjuwon, O. Bello; Olubukola, O. Babalola; Mobolaji, Adegboye; Muibat, O. Fashola; Temitope, K. Bello

    2018-01-01

    Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strains. Fermented Parkia biglobosa seeds (African locust bean) were screened for bacteriocin-producing lactic acid bacteria (LAB) with the characterization of putative bacteriocins. Bacteriocin-producing lactic acid bacteria (LAB) were identified by 16s rDNA sequencing. Molecular sizes of the bacteriocins were determined using the tricine-sodium dodecyl sulphate-polyacryla...

  7. Iron encrustations on filamentous algae colonized by Gallionella-related bacteria in a metal-polluted freshwater stream

    Science.gov (United States)

    Mori, J. F.; Neu, T. R.; Lu, S.; Händel, M.; Totsche, K. U.; Küsel, K.

    2015-09-01

    Filamentous macroscopic algae were observed in slightly acidic to circumneutral (pH 5.9-6.5), metal-rich stream water that leaked out from a former uranium mining district (Ronneburg, Germany). These algae differed in color and morphology and were encrusted with Fe-deposits. To elucidate their potential interaction with Fe(II)-oxidizing bacteria (FeOB), we collected algal samples at three time points during summer 2013 and studied the algae-bacteria-mineral compositions via confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra, and a 16S and 18S rRNA gene-based bacterial and algae community analysis. Surprisingly, sequencing analysis of 18S rRNA gene regions of green and brown algae revealed high homologies with the freshwater algae Tribonema (99.9-100 %). CLSM imaging indicated a loss of active chloroplasts in the algae cells, which may be responsible for the change in color in oxidation under the putative oxygen-saturated conditions that occur in association with photosynthetic algae. Quantitative PCR (polymerase chain reaction) revealed even higher Gallionella-related 16S rRNA gene copy numbers on the surface of green algae compared to the brown algae. The latter harbored a higher microbial diversity, including some putative predators of algae. A loss of chloroplasts in the brown algae could have led to lower photosynthetic activities and reduced EPS production, which is known to affect predator colonization. Collectively, our results suggest the coexistence of oxygen-generating algae Tribonema sp. and strictly microaerophilic neutrophilic FeOB in a heavy metal-rich environment.

  8. The DNA-mimic antirestriction proteins ArdA ColIB-P9, Arn T4, and Ocr T7 as activators of H-NS-dependent gene transcription.

    Science.gov (United States)

    Melkina, Olga E; Goryanin, Ignatiy I; Zavilgelsky, Gennadii B

    2016-11-01

    The antirestriction proteins ArdA ColIb-P9, Arn T4 and Ocr T7 specifically inhibit type I and type IV restriction enzymes and belong to the family of DNA-mimic proteins because their three-dimensional structure is similar to the double-helical B-form DNA. It is proposed that the DNA-mimic proteins are able to bind nucleoid protein H-NS and alleviate H-NS-silencing of the transcription of bacterial genes. Escherichia coli lux biosensors were constructed by inserting H-NS-dependent promoters into a vector, thereby placing each fragment upstream of the promoterless Photorhabdus luminescens luxCDABE operon. It was demonstrated that the DNA-mimic proteins ArdA, Arn and Ocr activate the transcription of H-NS-dependent promoters of the lux operon of marine luminescent bacteria (mesophilic Aliivibrio fischeri and psychrophilic Aliivibrio logei), and the dps gene from E. coli. It was also demonstrated that the ArdA antirestriction protein, the genes of which are located on transmissive plasmids ColIb-P9, R64, PK101, decreases levels of H-NS silencing of the PluxC promoter during conjugation in the recipient bacteria. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. Morphologic characterization and quantitative analysis on in vitro bacteria by nuclear techniques of measurement; Caracterizacao morfologica e analise quantitativa de bacterias in vitro por tecnicas nucleares de medidas

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Joana D' Arc Ramos

    2001-10-01

    The great difficulty to identify microorganisms (bacteria) from infectious processes is related to the necessary time to obtain a reliable result, about 72 hours. The purpose of this work is to establish a faster method to characterize bacterial morphologies through the use of neutron radiography, which can take about 5 hours. The samples containing the microorganisms, bacteria with different morphologies, after the appropriate microbiologic procedures were incubated with B{sup 10} for 30 minutes and soon after deposited in a plate of a solid detector of nuclear tracks (SSNTD), denominated CR-39. To obtain the images relative to bacteria, the detector was submitted to the flow of thermal neutrons of the order of 2.2 x 10{sup 5} n/cm{sup 2}.s from the J-9 channel of the Reactor Argonauta (IEN/CNEN). To observe the images from bacteria in each sample under an optical microscope, the sheets were chemically developed. The analysis of the images revealed morphologic differences among the genera (Gram positive from Gram-negative and coccus from bacillus), in samples containing either isolated or mixed bacteria. We thus verified the viability of the technique to achieve morphological characterization of different microorganisms. A quantitative approach seemed also to be feasible with the technique. The whole process took about 2 hours. (author)

  10. Investigations of the effect of electron-beam irradiation on bacteria in sewage sludge

    International Nuclear Information System (INIS)

    Osterstock, G.

    1976-01-01

    The effect of electron beams on bacteria was investigated in 2 experimental facilities. A 400 kV electron accelerator was used to irradiate sludge quantities of 10 l and 180 l. The total bacterial count, the number of coliform bacteria and, in injected sludge, the relative bacteria density of salmonella were investigated. A dose of 0.5 to 0.75 Mrad was required to reduce coliform bacteria to below the detectable level in 0.1 ml. With a dose of 1.5 Mrad salmonella were reduced by 6 orders of magnitude on the average. In addition, the dependence of the reduction in bacteria on the dose rate as well as on mixing of the irradiated material was investigated. Substantial reproduction of bacteria in digested sludge was found in all cases after the irradiation. (orig./MG) [de

  11. More, smaller bacteria in response to ocean's warming?

    KAUST Repository

    Moran, Xose Anxelu G.; Alonso-Sá ez, Laura; Nogueira, Enrique; Ducklow, Hugh W.; Gonzá lez, Natalia; Ló pez-Urrutia, Á ngel; Dí az-Pé rez, Laura; Calvo-Dí az, Alejandra; Arandia-Gorostidi, Nestor; Huete-Stauffer, Tamara M.

    2015-01-01

    Heterotrophic bacteria play a major role in organic matter cycling in the ocean. Although the high abundances and relatively fast growth rates of coastal surface bacterioplankton make them suitable sentinels of global change, past analyses have

  12. Gardnerella vaginalis and anaerobic bacteria in genital disease.

    Science.gov (United States)

    Tabaqchali, S; Wilks, M; Thin, R N

    1983-01-01

    In a study of Gardnerella vaginalis and anaerobic bacteria in non-specific vaginitis (NSV) and other genital disease 89 patients attending a genital medicine clinic had vaginal samples examined for conventional pathogens and for quantitative analysis of G vaginalis and aerobic and anaerobic bacterial flora. The overall incidence of G vaginalis was 20%; G vaginalis (mean concentration 7.0 log10/g of secretion) occurred predominantly in patients with NSV (57%) but also in sexual contacts of non-specific urethritis (NSU) (37.5%) and in patients with other conditions (11.8%). G vaginalis is therefore a relatively common isolate in patients with vaginal discharge. The concentration of aerobic and anaerobic bacteria ranged from 4.9-11.0 log10/g of secretion with an anaerobe-to-aerobe ratio of 10:1. Anaerobic bacteria, particularly anaerobic Gram-positive cocci (mean concentrations 7.7 log10/g), were present in patients with NSV and in association with G vaginalis, but they also occurred in other clinical groups and with other pathogens, particularly Trichomonas vaginalis. Anaerobic bacteria may therefore play an important role in the pathogenesis of vaginal infections. PMID:6600955

  13. Radiation-resistant asporogenic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K [Tokyo Univ. (Japan). Faculty of Agriculture

    1975-09-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned.

  14. Radiation-resistant asporogenic bacteria

    International Nuclear Information System (INIS)

    Yano, Keiji

    1975-01-01

    This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned. (Tsukamoto, Y.)

  15. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

  16. Molecular diversity, cultivation, and improved detection by fluorescent in situ hybridization of a dominant group of human gut bacteria related to Roseburia spp. or Eubacterium rectale.

    Science.gov (United States)

    Aminov, Rustam I; Walker, Alan W; Duncan, Sylvia H; Harmsen, Hermie J M; Welling, Gjalt W; Flint, Harry J

    2006-09-01

    Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 in feces from 10 healthy volunteers. Most of the diversity within this important group of butyrate-producing gut bacteria can apparently be retrieved through cultivation.

  17. Spoilage of vegetable crops by bacteria and fungi and related health hazards.

    Science.gov (United States)

    Tournas, V H

    2005-01-01

    After harvest, vegetables are often spoiled by a wide variety of microorganisms including many bacterial and fungal species. The most common bacterial agents are Erwinia carotovora, Pseudomonas spp., Corynebacterium, Xanthomonas campestris, and lactic acid bacteria with E. carotovora being the most common, attacking virtually every vegetable type. Fungi commonly causing spoilage of fresh vegetables are Botrytis cinerea, various species of the genera Alternaria, Aspergillus, Cladosporium, Colletotrichum, Phomopsis, Fusarium, Penicillium, Phoma, Phytophthora, Pythium and Rhizopus spp., Botrytis cinerea, Ceratocystis fimbriata, Rhizoctonia solani, Sclerotinia sclerotiorum, and some mildews. A few of these organisms show a substrate preference whereas others such as Botrytis cinerea, Colletotrichum, Alternaria, Cladosporium, Phytophthora, and Rhizopus spp., affect a wide variety of vegetables causing devastating losses. Many of these agents enter the plant tissue through mechanical or chilling injuries, or after the skin barrier has been broken down by other organisms. Besides causing huge economic losses, some fungal species could produce toxic metabolites in the affected sites, constituting a potential health hazard for humans. Additionally, vegetables have often served as vehicles for pathogenic bacteria, viruses, and parasites and were implicated in many food borne illness outbreaks. In order to slow down vegetable spoilage and minimize the associated adverse health effects, great caution should be taken to follow strict hygiene, good agricultural practices (GAPs) and good manufacturing practices (GMPs) during cultivation, harvest, storage, transport, and marketing.

  18. Abundance of thraustochytridsand bacteria in the equatorial Indian Ocean, in relation totransparent exopolymeric particles (TEPs)

    Digital Repository Service at National Institute of Oceanography (India)

    Damare, V.; Raghukumar, S.

    Thraustochytrid protists are often abundant in coastal waters. However, their population dynamics and substrate preferences in the oceanic water column are poorly understood.We studied the abundance and distribution of thraustochytrids, bacteria...

  19. Heterologous surface display on lactic acid bacteria: non-GMO alternative?

    Science.gov (United States)

    Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

    2015-01-01

    Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union.

  20. Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria

    DEFF Research Database (Denmark)

    Gregersen, Lea Haarup; Bryant, Donald A.; Frigaard, Niels-Ulrik

    2011-01-01

    Green sulfur bacteria (GSB) constitute a closely related group of photoautotrophic and thiotrophic bacteria with limited phenotypic variation. They typically oxidize sulfide and thiosulfate to sulfate with sulfur globules as an intermediate. Based on genome sequence information from 15 strains...... product is further oxidized to sulfite by the dissimilatory sulfite reductase (DSR) system. This system consists of components horizontally acquired partly from sulfide-oxidizing and partly from sulfate-reducing bacteria. Depending on the strain, the sulfite is probably oxidized to sulfate by one of two...... in sulfate formation in other bacteria has been replaced by the DSR system in GSB. Sequence analyses suggested that the conserved soxJXYZAKBW gene cluster was horizontally acquired by Chlorobium phaeovibrioides DSM 265 from the Chlorobaculum lineage and that this acquisition was mediated by a mobile genetic...

  1. Bacteria-surface interactions.

    Science.gov (United States)

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  2. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  3. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

  4. Engineering bacteria for enhanced polyhydroxyalkanoates (PHA biosynthesis

    Directory of Open Access Journals (Sweden)

    Guo-Qiang Chen

    2017-09-01

    Full Text Available Polyhydroxyalkanoates (PHA have been produced by some bacteria as bioplastics for many years. Yet their commercialization is still on the way. A few issues are related to the difficulty of PHA commercialization: namely, high cost and instabilities on molecular weights (Mw and structures, thus instability on thermo-mechanical properties. The high cost is the result of complicated bioprocessing associated with sterilization, low conversion of carbon substrates to PHA products, and slow growth of microorganisms as well as difficulty of downstream separation. Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles, developments of engineering approaches for the extremophiles, increase on carbon substrates to PHA conversion and controlling Mw of PHA. The concept proof studies could still be conducted on E. coli or Pseudomonas spp. that are easily used for molecular manipulations. In this review, we will use E. coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.

  5. "DRUG RESISTANCE PATTERN IN ISOLATED BACTERIA FROM BLOOD CULTURES"

    Directory of Open Access Journals (Sweden)

    A. Sobhani

    2004-05-01

    Full Text Available Bacteremia is an important infectious disease which may lead to death. Common bacteria and pattern of antibiotic resistance in different communities are different and understanding these differences is important. In the present study, relative frequency and pattern of drug resistance have been examined in bacteria isolated from blood cultures in Razi Hospital laboratory. The method of the study was descriptive. Data collection was carried out retrospectively. Total sample consisted of 311 positive blood cultures from 1999 to 2001. Variables under study were bacterial strains, antibiotics examined in antibiogram, microbial resistance, and patients' age and sex. The most common isolated bacteria were Salmonella typhi (22.2% and the least common ones were Citrobacter (1.6%. The highest antibiotic resistance was seen against amoxicillin (88.4%. The proportion of males to females was1: 1/1 and the most common age group was 15-44 (47.3%. Common bacteria and pattern of antibiotic resistance were different in some areas and this subject requires further studies in the future.

  6. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

    OpenAIRE

    Wilis Ari Setyati; Muhammad Zainuddin; Person Pesona Renta

    2017-01-01

    Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36...

  7. Bacteria versus selenium: A view from the inside out

    Science.gov (United States)

    Staicu, Lucian; Oremland, Ronald S.; Tobe, Ryuta; Mihara, Hisaaki

    2017-01-01

    Bacteria and selenium (Se) are closely interlinked as the element serves both essential nutrient requirements and energy generation functions. However, Se can also behave as a powerful toxicant for bacterial homeostasis. Conversely, bacteria play a tremendous role in the cycling of Se between different environmental compartments, and bacterial metabolism has been shown to participate to all valence state transformations undergone by Se in nature. Bacteria possess an extensive molecular repertoire for Se metabolism. At the end of the 1980s, a novel mode of anaerobic respiration based on Se oxyanions was experimentally documented for the first time. Following this discovery, specific enzymes capable of reducing Se oxyanions and harvesting energy were found in a number of anaerobic bacteria. The genes involved in the expression of these enzymes have later been identified and cloned. This iterative approach undertaken outside-in led to the understanding of the molecular mechanisms of Se transformations in bacteria. Based on the extensive knowledge accumulated over the years, we now have a full(er) view from the inside out, from DNA-encoding genes to enzymes and thermodynamics. Bacterial transformations of Se for assimilatory purposes have been the object of numerous studies predating the investigation of Se respiration. Remarkable contributions related to the understating of the molecular picture underlying seleno-amino acid biosynthesis are reviewed herein. Under certain circumstances, Se is a toxicant for bacterial metabolism and bacteria have evolved strategies to counteract this toxicity, most notably by the formation of elemental Se (nano)particles. Several biotechnological applications, such as the production of functional materials and the biofortification of crop species using Se-utilizing bacteria, are presented in this chapter.

  8. Cadmium resistance of endophytic bacteria and rizosféricas bacteria isolated from Oriza sativa in Colombia

    Directory of Open Access Journals (Sweden)

    Nataly Ayubb T

    2017-12-01

    Full Text Available The present study had as objective to evaluate in vitro the resistance of endophytic bacteria and rizospheric bacteria to different concentrations of Cadmium.This bacteria were isolated fron different tissues of commercial rice varieties and from bacteria isolated from the rhizosphere in rice plantations of the Nechí (Antioquía and Achí (Bolivar.  Plant growth promotion was evaluated in vitro by nitrogen fixation, phosphate solubilization and siderophores production of endophytic bacteria. Of each tissue isolated from rice plants was carried out isolation in culture medium for endophytic bacteria, and the soil samples were serially diluted in peptone water. Each sample was determined the population density by counting in CFU / g of tissue and morphotypes were separated by shape, color, size and appearance in culture media. Significant differences were observed for density population of bacteria with respect to tissue, with higher values in root (4x1011 g/root, followed of the stem (3x1010g/etem, leaf (5x109 g/ leaf, flag leaf (3x109 g/ flag leaf and with less density in panicle (4x108 g/panicle. The results of the identification with kit API were confirmed the presence of endophytic bacteria Burkholderia cepaceae and rizospheric bacteria Pseudomona fluorescens With the ability to tolerate different concentrations of Cd, fix nitrogen, solubilize phosphates and produce siderophores.

  9. Nitrogen-fixing bacteria in Mediterranean seagrass (Posidonia oceanica) roots

    KAUST Repository

    Garcias Bonet, Neus

    2016-03-09

    Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

  10. Characterization of radiation-resistant vegetative bacteria in beef

    International Nuclear Information System (INIS)

    Welch, A.B.; Maxcy, R.B.

    1975-01-01

    Ground beef contains numerous microorganisms of various types. The commonly recognized bacteria are associated with current problems of spoilage. Irradiation, however, contributes a new factor through selective destruction of the microflora. The residual microorganisms surviving a nonsterilizing dose are predominantly gram-negative coccobacilli. Various classifications have been given, e.g., Moraxella, Acinetobacter, Achromobacter, etc. For a more detailed study of these radiation-resistant bacteria occurring in ground beef, an enrichment procedure was used for isolation. By means of morphological and biochemical tests, most of the isolates were found to be Moraxella, based on current classifications. The range of growth temperatures was from 2 to 50 C. These bacteria were relatively heat sensitive, e.g., D 10 of 5.4 min at 70 0 C or less. The radiation resistance ranged from D 10 values of 273 to 2,039 krad. Thus, some were more resistant than any presently recognized spores. A reference culture of Moraxella osloensis was irradiated under conditions comparable to the enrichment procedure used with the ground beef. The only apparent changes were in morphology and penicillin sensitivity. However, after a few subcultures these bacteria reverted to the characteristics of the parent strain. Thus, it is apparent that these isolates are a part of the normal flora of ground beef and not aberrant forms arising from the irradiation procedure. The significance, if any, of these bacteria is not presently recognized. (auth)

  11. Potential for luxS related signalling in marine bacteria and production of autoinducer-2 in the genus Shewanella

    Directory of Open Access Journals (Sweden)

    Wagner-Döbler Irene

    2008-01-01

    Full Text Available Abstract Background The autoinducer-2 (AI-2 group of signalling molecules are produced by both Gram positive and Gram negative bacteria as the by-product of a metabolic transformation carried out by the LuxS enzyme. They are the only non species-specific quorum sensing compounds presently known in bacteria. The luxS gene coding for the AI-2 synthase enzyme was found in many important pathogens. Here, we surveyed its occurrence in a collection of 165 marine isolates belonging to abundant marine phyla using conserved degenerated PCR primers and sequencing of selected positive bands to determine if the presence of the luxS gene is phylogenetically conserved or dependent on the habitat. Results The luxS gene was not present in any of the Alphaproteobacteria (n = 71 and Bacteroidetes strains (n = 29 tested; by contrast, these bacteria harboured the sahH gene, coding for an alternative enzyme for the detoxification of S-adenosylhomocysteine (SAH in the activated methyl cycle. Within the Gammaproteobacteria (n = 76, luxS was found in all Shewanella, Vibrio and Alteromonas isolates and some Pseudoalteromonas and Halomonas species, while sahH was detected in Psychrobacter strains. A number of Gammaproteobacteria (n = 27 appeared to have neither the luxS nor the sahH gene. We then studied the production of AI-2 in the genus Shewanella using the Vibrio harveyi bioassay. All ten species of Shewanella tested produced a pronounced peak of AI-2 towards the end of the exponential growth phase in several media investigated. The maximum of AI-2 activity was different in each Shewanella species, ranging from 4% to 46% of the positive control. Conclusion The data are consistent with those of fully sequenced bacterial genomes and show that the potential for luxS related signalling is dependent on phylogenetic affiliation rather than ecological niche and is largest in certain groups of Gammaproteobacteria in the marine environment. This is the first report on AI-2

  12. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  13. Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

    OpenAIRE

    Bertelsen, Hans; Andersen, Hans; Tvede, Michael

    2011-01-01

    A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

  14. METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

    NARCIS (Netherlands)

    Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

    2017-01-01

    A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

  15. Bioluminescent bioreporter sensing of foodborne toxins

    Science.gov (United States)

    Fraley, Amanda C.; Ripp, Steven; Sayler, Gary S.

    2004-06-01

    Histamine is the primary etiological agent in the foodborne disease scombrotoxicosis, one of the most common food toxicities related to fish consumption. Procedures for detecting histamine in fish products are available, but are often too expensive or too complex for routine use. As an alternative, a bacterial bioluminescent bioreporter has been constructed to develop a biosensor system that autonomously responds to low levels of histamine. The bioreporter contains a promoterless Photorhabdus luminescens lux operon (luxCDABE) fused with the Vibrio anguillarum angR regulatory gene promoter of the anguibactin biosynthetic operon. The bioreporter emitted 1.46 times more bioluminescence than background, 30 minutes after the addition of 100mM histamine. However, specificity was not optimal, as this biosensor generated significant bioluminescence in the presence of L-proline and L-histidine. As a means towards improving histamine specificity, the promoter region of a histamine oxidase gene from Arthrobacter globiformis was cloned upstream of the promotorless lux operon from Photorhabdus luminescens. This recently constructed whole-cell, lux-based bioluminescent bioreporter is currently being tested for optimal performance in the presence of histamine in order to provide a rapid, simple, and inexpensive model sensor for the detection of foodborne toxins.

  16. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

  17. Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

    Science.gov (United States)

    Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

    2013-01-01

    Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID

  18. Re-evaluating the role of bacteria in gerbera vase life

    NARCIS (Netherlands)

    Schouten, Rob E.; Verdonk, Julian C.; Meeteren, van Uulke

    2018-01-01

    The relation between bacteria numbers in vase water and vase life of gerbera cut flowers has recently been challenged because of reported negative effects of bactericidal compounds. This relation is investigated using two types of experiments that do not rely on antimicrobial compounds. The first

  19. Symbiotic bacteria contribute to increasing the population size of a freshwater crustacean, Daphnia magna.

    Science.gov (United States)

    Peerakietkhajorn, Saranya; Tsukada, Koji; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

    2015-04-01

    The filter-feeding crustacean Daphnia is a key organism in freshwater ecosystems. Here, we report the effect of symbiotic bacteria on ecologically important life history traits, such as population dynamics and longevity, in Daphnia magna. By disinfection of the daphniid embryos with glutaraldehyde, aposymbiotic daphniids were prepared and cultured under bacteria-free conditions. Removal of bacteria from the daphniids was monitored by quantitative polymerase chain reaction for bacterial 16S rRNA gene. The population of aposymbiotic daphniids was reduced 10-folds compared with that of the control daphniids. Importantly, re-infection with symbiotic bacteria caused daphniids to regain bacteria and increase their fecundity to the level of the control daphniids, suggesting that symbiotic bacteria regulate Daphnia fecundity. To identify the species of symbiotic bacteria, 16S rRNA genes of bacteria in daphniids were sequenced. This revealed that 50% of sequences belonged to the Limnohabitans sp. of the Betaproteobacteria class and that the diversity of bacterial taxa was relatively low. These results suggested that symbiotic bacteria have a beneficial effect on D. magna, and that aposymbiotic Daphnia are useful tools in understanding the role of symbiotic bacteria in the environmental responses and evolution of their hosts. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Isolation and Presumptive Identification of Adherent Epithelial Bacteria (“Epimural” Bacteria) from the Ovine Rumen Wall

    OpenAIRE

    Mead, Lorna J.; Jones, G. A.

    1981-01-01

    One hundred sixty-one strains of adherent bacteria were isolated under anaerobic conditions from four sites on the rumen epithelial surface of sheep fed hay or a hay-grain ration. Before isolation of bacteria, rumen tissue was washed six times in an anaerobic dilution solution, and viable bacteria suspended in the washings were counted. Calculation indicated that unattached bacteria would have been removed from the tissue by this procedure, but a slow and progressive release of attached bacte...

  1. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    and fusion event might be very ancient indeed, preceding the divergence of bacteria and eukaryotes. It is unclear whether all the bacterial homologues are derived from horizontal gene transfer, but those from the plant symbionts probably are. The homologues from oceanic bacteria are most closely related to memapsins (or BACE-1 and BACE-2, but are so divergent that they are close to the root of the phylogenetic tree and to the division of the A1 family into two subfamilies.

  2. Re-engineering bacteria for ethanol production

    Science.gov (United States)

    Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

    2014-05-06

    The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

  3. Frost-related dieback of Swedish and Estonian Salix plantations due to pathogenic and ice nucleation-active bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cambours, M.A.

    2004-07-01

    During the past decade, important dieback has been observed in short-rotation forestry plantations of Salix viminalis and S. dasyclados in Sweden and Estonia, plantations from which the isolation of ice nucleation-active (INA) and pathogenic bacteria has also been reported. This thesis investigates the connection between bacterial infection and frost as a possible cause for such damage, and the role played by internal and external factors (e.g. plant frost sensitivity, fertilisation) in the dieback observed. Bacterial floras isolated from ten Salix clones growing on fertilised/unfertilised mineral soil or nitrogen-rich organic soil, were studied. Culturable bacterial communities present both in internal necrotic tissues and on the plant surface (i.e. epiphytes) were isolated on two occasions (spring and autumn). The strains were biochemically characterised (with gram, oxidase and fluorescence tests), and tested for ice nucleation-activity. Their pathogenic properties were studied with and without association to a freezing stress. Certain strains were eventually identified with BIOLOG plates and 16S rRNA analysis. A high number of culturable bacterial strains was found in the plant samplings, belonging mainly to Erwinia and Sphingomonas spp.; pathogenic and INA communities being mostly Erwinia-, Sphingomonas- and Xanthomonas-like. The generally higher plant dieback noted in the field on nutrient-rich soils and for frost sensitive clones was found connected to higher numbers of pathogenic and INA bacteria in the plants. We thus confirm Salix dieback to be related to a synergistic effect of frost and bacterial infection, possibly aggravated by fertilisation.

  4. The impact of bacteria of circulating water on apatite-nepheline ore flotation.

    Science.gov (United States)

    Evdokimova, G A; Gershenkop, A Sh; Fokina, N V

    2012-01-01

    A new phenomenon has been identified and studied-the impact of bacteria on the benefication process of non-sulphide ores using circulating water supply-a case study of apatite-nepheline ore. It is shown that bacteria deteriorate the floatability of apatite due to their interaction with active centres of calcium-containing minerals and intense flocculation, resulting in a decrease of the flotation process selectivity thus deteriorating the quality of concentrate. Based on the comparative analysis of primary sequences of 16S rRNA genes, there have been identified dominating bacteria species, recovered from the circulating water used at apatite-nepheline concentrating mills, and their phylogenetic position has been determined. All the bacteria were related to γ-Proteobacteria, including the Acinetobacter species, Pseudomonas alcaliphila, Ps. plecoglossicida, Stenotrophomonas rhizophila. A method of non-sulphide ores flotation has been developed with consideration of the bacterial factor. It consists in use of small concentrations of sodium hypochlorite, which inhibits the development of bacteria in the flotation of apatite-nepheline ores.

  5. Brief ultrasonication improves detection of biofilm-formative bacteria around a metal implant.

    Science.gov (United States)

    Kobayashi, Naomi; Bauer, Thomas W; Tuohy, Marion J; Fujishiro, Takaaki; Procop, Gary W

    2007-04-01

    Biofilms are complex microenvironments produced by microorganisms on surfaces. Ultrasonication disrupts biofilms and may make the microorganism or its DNA available for detection. We determined whether ultrasonication could affect our ability to detect bacteria adherent to a metal substrate. A biofilm-formative Staphylococcus aureus strain was used for an in vitro implant infection model (biofilm-formative condition). We used quantitative culture and real time-polymerase chain reaction to determine the influence of different durations of ultrasound on bacterial adherence and viability. Sonication for 1 minute increased the yield of bacteria. Sonication longer than 5 minutes led to fewer bacterial colonies by conventional culture but not by polymerase chain reaction. This suggests short periods of sonication help release bacteria from the metal substrate by disrupting the biofilm, but longer periods of sonication lyse bacteria prohibiting their detection in microbiologic cultures. A relatively short duration of sonication may be desirable for maximizing detection of biofilm-formative bacteria around implants by culture or polymerase chain reaction.

  6. Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A

    2004-01-01

    Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... a and carotenoid biosynthesis enzymes, gene cluster analysis in Cfx. aurantiacus, and gene inactivation studies in Chl. tepidum. Based on these results, BChl a and BChl c biosynthesis is similar in the two organisms, whereas carotenoid biosynthesis differs significantly. In agreement with its facultative anaerobic...

  7. How honey kills bacteria

    NARCIS (Netherlands)

    Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

  8. Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing

    Directory of Open Access Journals (Sweden)

    Allyson Lee Brady

    2015-09-01

    Full Text Available Carbon monoxide (CO is a potential energy and carbon source for thermophilic bacteria in geothermal environments. Geothermal sites ranging in temperature from 45–65°C were investigated for the presence and activity of anaerobic CO-oxidizing bacteria. Anaerobic CO oxidation potentials were measured at up to 48.9 µmoles CO day-1 g (wet weight-1 within 5 selected sites. Active anaerobic carboxydotrophic bacteria were identified using 13CO DNA stable isotope probing (SIP combined with pyrosequencing of 16S rRNA genes amplified from labeled DNA. Bacterial communities identified in heavy DNA fractions were predominated by Firmicutes, which comprised up to 95% of all sequences in 13CO incubations. The predominant bacteria that assimilated 13C derived from CO were closely related (>98% to genera of known carboxydotrophs including Thermincola, Desulfotomaculum, Thermolithobacter and Carboxydocella, although a few species with lower similarity to known bacteria were also found that may represent previously unconfirmed CO-oxidizers. While the distribution was variable, many of the same OTUs were identified across sample sites from different temperature regimes. These results show that bacteria capable of using CO as a carbon source are common in geothermal springs, and that thermophilic carboxydotrophs are probably already quite well known from cultivation studies.

  9. U.V. repair in deep-sea bacteria

    International Nuclear Information System (INIS)

    Lutz, L.; Yayanos, A.A.

    1986-01-01

    Exposure of cells to light of less than 320 nanometers wavelengths may lead to lethal lesions and perhaps carcinogenesis. Many organisms have evolved mechanisms to repair U.V. light-induced damage. Organisms such as deep-sea bacteria are presumably never exposed to U.V. light and perhaps occasionally to visible from bioluminescence. Thus, the repair of U.V. damage in deep-sea bacterial DNA might be inefficient and repair by photoreactivation unlikely. The bacteria utilized in this investigation are temperature sensitive and barophilic. Four deep-sea isolates were chosen for this study: PE-36 from 3584 m, CNPT-3 from 5782 m, HS-34 from 5682 m, and MT-41 from 10,476 m, all are from the North Pacific ocean. The deep-sea extends from 1100 m to depths greater than 7000 m. It is a region of relatively uniform conditions. The temperature ranges from 5 to -1 0 C. There is no solar light in the deep-sea. Deep-sea bacteria are sensitive to U.V. light; in fact more sensitive than a variety of terrestrial and sea-surface bacteria. All four isolates demonstrate thymine dimer repair. Photoreactivation was observed in only MT-41. The other strains from shallower depths displayed no photoreactivation. The presence of DNA sequences homologous to the rec A, uvr A, B, and C and phr genes of E. coli have been examined by Southern hybridization techniques

  10. Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Wilis Ari Setyati

    2017-06-01

    Full Text Available Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36. Pathogenic bacteria Vibrio harveyi was used as positive control. Pathogenic assay was carried out in two different bacterial concentrations, i.e. 10⁸ and 10⁶ cells.mL-1. The results showed that the lowest survival rate (SR of shrimp larvae in positive control V. harveyi was 53 and 65%. Whereas isolates with the highest SR value (100% were obtained from bacteria coded as 13 and 30. Isolates no. 19, 33 and 36 had SR of more than 90%. Total plate count (TPC data showed that the bacteria increased significantly at the end of the study with an average increase value of 24%. The smallest TPC value was shown by bacterial isolate no. 19, while the largest was obtained from the isolate no. 13. These results suggest that all probiotic bacteria were not pathogenic to the vannamei shrimp larvae.   Keywords: aquaculture, shrimp, bioremediation, pathogenesis, vibrio.

  11. Diversity of bacteria carried by pinewood nematode in USA and phylogenetic comparison with isolates from other countries.

    Directory of Open Access Journals (Sweden)

    Diogo Neves Proença

    Full Text Available Pine wilt disease (PWD is native to North America and has spread to Asia and Europe. Lately, mutualistic relationship has been suggested between the pinewood nematode (PWN, Bursaphelenchus xylophilus the causal nematode agent of PWD, and bacteria. In countries where PWN occurs, nematodes from diseased trees were reported to carry bacteria from several genera. However no data exists for the United States. The objective of this study was to evaluate the diversity of the bacterial community carried by B. xylophilus, isolated from different Pinus spp. with PWD in Nebraska, United States. The bacteria carried by PWN belonged to Gammaproteobacteria (79.9%, Betaproteobacteria (11.7%, Bacilli (5.0%, Alphaproteobacteria (1.7% and Flavobacteriia (1.7%. Strains from the genera Chryseobacterium and Pigmentiphaga were found associated with the nematode for the first time. These results were compared to results from similar studies conducted from other countries of three continents in order to assess the diversity of bacteria with associated with PWN. The isolates from the United States, Portugal and China belonged to 25 different genera and only strains from the genus Pseudomonas were found in nematodes from all countries. The strains from China were closely related to P. fluorescens and the strains isolated from Portugal and USA were phylogenetically related to P. mohnii and P. lutea. Nematodes from the different countries are associated with bacteria of different species, not supporting a relationship between PWN with a particular bacterial species. Moreover, the diversity of the bacteria carried by the pinewood nematode seems to be related to the geographic area and the Pinus species. The roles these bacteria play within the pine trees or when associated with the nematodes, might be independent of the presence of the nematode in the tree and only related on the bacteria's relationship with the tree.

  12. Diversity patterns of microbial eukaryotes mirror those of bacteria in Antarctic cryoconite holes.

    Science.gov (United States)

    Sommers, Pacifica; Darcy, John L; Gendron, Eli M S; Stanish, Lee F; Bagshaw, Elizabeth A; Porazinska, Dorota L; Schmidt, Steven K

    2018-01-01

    Ice-lidded cryoconite holes on glaciers in the Taylor Valley, Antarctica, provide a unique system of natural mesocosms for studying community structure and assembly. We used high-throughput DNA sequencing to characterize both microbial eukaryotic communities and bacterial communities within cryoconite holes across three glaciers to study similarities in their spatial patterns. We expected that the alpha (phylogenetic diversity) and beta (pairwise community dissimilarity) diversity patterns of eukaryotes in cryoconite holes would be related to those of bacteria, and that they would be related to the biogeochemical gradient within the Taylor Valley. We found that eukaryotic alpha and beta diversity were strongly related to those of bacteria across scales ranging from 140 m to 41 km apart. Alpha diversity of both was significantly related to position in the valley and surface area of the cryoconite hole, with pH also significantly correlated with the eukaryotic diversity. Beta diversity for both bacteria and eukaryotes was significantly related to position in the valley, with bacterial beta diversity also related to nitrate. These results are consistent with transport of sediments onto glaciers occurring primarily at local scales relative to the size of the valley, thus creating feedbacks in local chemistry and diversity. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Biodegradation of mixtures of pesticides by bacteria and white rot fungi

    OpenAIRE

    Gouma, Sofia

    2009-01-01

    The objective of this study was to examine the potential for degradation of mixtures of pesticides (chlorpyrifos, linuron, metribuzin) by a range of bacteria and fungi and to relate this capability to enzyme production and quantify the rates of degradation of the components of the mixture of xenobiotic compounds. Overall, although bacteria (19 Bacillus and 4 Pseudomonas species) exhibited tolerance to the individual and micture of pesticides actual degradation was not eviden...

  14. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  15. Fluctuating hydrodynamics and microrheology of a dilute suspension of swimming bacteria.

    Science.gov (United States)

    Lau, A W C; Lubensky, T C

    2009-07-01

    A bacterial bath is a model active system consisting of a population of rodlike motile or self-propelled bacteria suspended in a fluid environment. This system can be viewed as an active, nonequilibrium version of a lyotropic liquid crystal or as a generalization of a driven diffusive system. We derive a set of phenomenological equations, which include the effects of internal force generators in the bacteria, describing the hydrodynamic flow, orientational dynamics of the bacteria, and fluctuations induced by both thermal and nonthermal noises. These equations violate the fluctuation dissipation theorem and the Onsager reciprocity relations. We use them to provide a quantitative account of results from recent microrheological experiments on bacterial baths.

  16. Beer spoilage bacteria and hop resistance

    NARCIS (Netherlands)

    Sakamoto, K; Konings, WN

    2003-01-01

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and

  17. Isolation and characterization of biosurfactant producing bacteria from Persian Gulf (Bushehr provenance)

    International Nuclear Information System (INIS)

    Hassanshahian, Mehdi

    2014-01-01

    Highlights: • Biosurfactant producing bacteria were isolated from Persian Gulf. • There is high diversity of biosurfactant producing bacteria in the Persian Gulf. • These bacteria are very useful for management of oil pollution in the sea. - Abstract: Biosurfactants are surface active materials that are produced by some microorganisms. These molecules increase biodegradation of insoluble pollutants. In this study sediments and seawater samples were collected from the coastline of Bushehr provenance in the Persian Gulf and their biosurfactant producing bacteria were isolated. Biosurfactant producing bacteria were isolated by using an enrichment method in Bushnell-Hass medium with diesel oil as the sole carbon source. Five screening tests were used for selection of Biosurfactant producing bacteria: hemolysis in blood agar, oil spreading, drop collapse, emulsification activity and Bacterial Adhesion to Hydrocarbon test (BATH). These bacteria were identified using biochemical and molecular methods. Eighty different colonies were isolated from the collected samples. The most biosurfactant producing isolates related to petrochemical plants of Khark Island. Fourteen biosurfactant producing bacteria were selected between these isolates and 7 isolates were screened as these were predominant producers that belong to Shewanella alga, Shewanella upenei, Vibrio furnissii, Gallaecimonas pentaromativorans, Brevibacterium epidermidis, Psychrobacter namhaensis and Pseudomonas fluorescens. The largest clear zone diameters in oil spreading were observed for G. pentaromativorans strain O15. Also, this strain has the best emulsification activity and reduction of surface tension, suggesting it is the best of thee isolated strains. The results of this study confirmed that there is high diversity of biosurfactant producing bacteria in marine ecosystem of Iran and by application of these bacteria in petrochemical waste water environmental problems can be assisted

  18. Transfer of DNA from Bacteria to Eukaryotes

    Directory of Open Access Journals (Sweden)

    Benoît Lacroix

    2016-07-01

    Full Text Available Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen, Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium, or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs, the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

  19. Bacteria in the Tatahouine meteorite: nanometric-scale life in rocks.

    Science.gov (United States)

    Gillet, P h; Barrat, J A; Heulin, T h; Achouak, W; Lesourd, M; Guyot, F; Benzerara, K

    2000-02-15

    We present a study of the textural signature of terrestrial weathering and related biological activity in the Tatahouine meteorite. Scanning and transmission electron microscopy images obtained on the weathered samples of the Tatahouine meteorite and surrounding soil show two types of bacteria-like forms lying on mineral surfaces: (1) rod-shaped forms (RSF) about 70-80 nm wide and ranging from 100 nm to 600 nm in length; (2) ovoid forms (OVF) with diameters between 70 and 300 nm. They look like single cells surrounded by a cell wall. Only Na, K, C, O and N with traces of P and S are observed in the bulk of these objects. The chemical analyses and electron diffraction patterns confirm that the RSF and OVF cannot be magnetite or other iron oxides, iron hydroxides, silicates or carbonates. The sizes of the RSF and OVF are below those commonly observed for bacteria but are very similar to some bacteria-like forms described in the Martian meteorite ALH84001. All the previous observations strongly suggest that they are bacteria or their remnants. This conclusion is further supported by microbiological experiments in which pleomorphic bacteria with morphology similar to the OVF and RSF objects are obtained from biological culture of the soil surrounding the meteorite pieces. The present results show that bacteriomorphs of diameter less than 100 nm may in fact represent real bacteria or their remnants.

  20. Human body may produce bacteria.

    Science.gov (United States)

    Salerian, Alen J

    2017-06-01

    "Human body may produce bacteria" proposes that human body may produce bacteria and represent an independent source of infections contrary to the current paradigm of infectious disorders proposed by Louis Pasteur in 1880. The following observations are consistent with this hypothesis: A. Bidirectional transformations of both living and nonliving things have been commonly observed in nature. B. Complex multicellular organisms harbor the necessary properties to produce bacteria (water, nitrogen and oxygen). C. Physical laws suggest any previously observed phenomenon or action will occur again (life began on earth; a non living thing). D. Animal muscle cells may generate energy (fermentation). E. Sterilized food products (i.e. boiled eggs), may produce bacteria and fungus under special conditions and without any exposure to foreign living cells. "Human body may produce bacteria" may challenge the current medical paradigm that views human infectious disorders as the exclusive causative byproducts of invading foreign cells. It may also introduce new avenues to treat infectious disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Novel, Highly Specific N-Demethylases Enable Bacteria To Live on Caffeine and Related Purine Alkaloids

    Science.gov (United States)

    Summers, Ryan M.; Louie, Tai Man; Yu, Chi-Li; Gakhar, Lokesh; Louie, Kailin C.

    2012-01-01

    The molecular basis for the ability of bacteria to live on caffeine as a sole carbon and nitrogen source is unknown. Pseudomonas putida CBB5, which grows on several purine alkaloids, metabolizes caffeine and related methylxanthines via sequential N-demethylation to xanthine. Metabolism of caffeine by CBB5 was previously attributed to one broad-specificity methylxanthine N-demethylase composed of two subunits, NdmA and NdmB. Here, we report that NdmA and NdmB are actually two independent Rieske nonheme iron monooxygenases with N1- and N3-specific N-demethylation activity, respectively. Activity for both enzymes is dependent on electron transfer from NADH via a redox-center-dense Rieske reductase, NdmD. NdmD itself is a novel protein with one Rieske [2Fe-2S] cluster, one plant-type [2Fe-2S] cluster, and one flavin mononucleotide (FMN) per enzyme. All ndm genes are located in a 13.2-kb genomic DNA fragment which also contained a formaldehyde dehydrogenase. ndmA, ndmB, and ndmD were cloned as His6 fusion genes, expressed in Escherichia coli, and purified using a Ni-NTA column. NdmA-His6 plus His6-NdmD catalyzed N1-demethylation of caffeine, theophylline, paraxanthine, and 1-methylxanthine to theobromine, 3-methylxanthine, 7-methylxanthine, and xanthine, respectively. NdmB-His6 plus His6-NdmD catalyzed N3-demethylation of theobromine, 3-methylxanthine, caffeine, and theophylline to 7-methylxanthine, xanthine, paraxanthine, and 1-methylxanthine, respectively. One formaldehyde was produced from each methyl group removed. Activity of an N7-specific N-demethylase, NdmC, has been confirmed biochemically. This is the first report of bacterial N-demethylase genes that enable bacteria to live on caffeine. These genes represent a new class of Rieske oxygenases and have the potential to produce biofuels, animal feed, and pharmaceuticals from coffee and tea waste. PMID:22328667

  2. Effects of Ethanolic Ferolagu angulata Extract on Pathogenic Gastrointestinal Bacteria and Probiotic Bacteria in Skimmed Milk Medium

    Directory of Open Access Journals (Sweden)

    Reza Naghiha

    2016-12-01

    Full Text Available Background:    Due to excessive consumption of synthetic drugs, drug resistance rate of pathogenic bacteria is increasing and there is an ever-increasing need to find new safe compounds to tackle this problem. This study was conducted to investigate the consequences of chavill extract on the growth and viability of gastrointestinal pathogenic bacterium and probiotics bacteria. Methods:    The experiment contained three levels of the chavill extract concentrations (0, 1 and 3% which were added to the milk free fat in accompany with three probiotic bacteria (Lactobacillus acidophilus, Lactobacillus casei and lactobacillus plantaram and a pathogenic gastrointestinal bacterium (Salmonella typhimurium. Bacterial inoculums (1×107 CFU/ml with different concentrations of chavill extract were added to skimmed milk medium and bacteria growth were enumerated. Results:  The concentration of 1% chavill extract significantly increased the total count of probiotic bacteria compared to the control group, while the number of pathogenic bacteria was decreased. At 3% chavill extract the growth of Lactobacillus acidophilus and Lactobacillus plantaram were increased. On the other hand, it prevented the growth of Salmonella typhimurium Conclusion:   Chavill extracts would play as an alternative to antibiotics in pharmacological studies to decreases harmful bacteria and increase probiotic bacteria.

  3. [Infectious risk related to the formation of multi-species biofilms (Candida - bacteria) on peripheral vascular catheters].

    Science.gov (United States)

    Seghir, A; Boucherit-Otmani, Z; Sari-Belkharroubi, L; Boucherit, K

    2017-03-01

    The Candida yeasts are the fourth leading cause of death from systemic infections, the risk may increase when the infection also involves bacteria. Yeasts and bacteria can adhere to medical implants, such as peripheral vascular catheters, and form a multicellular structures called "mixed biofilms" more resistant to antimicrobials agents. However, the formation of mixed biofilms on implants leads to long-term persistent infections because they can act as reservoirs of pathogens that have poorly understood interactions. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. [Unique properties of highly radioresistant bacteria].

    Science.gov (United States)

    Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

    2000-01-01

    In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

  5. LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

    Science.gov (United States)

    Forty-five isolates of HPC bacteria, most of which express virulence-related characteristics are being tested for pathogenicity in immunocompromised mice. All forty-five were negative for facultative intracellular pathogenicity. All twenty-three isolates tested thus far were a...

  6. Bactericide for sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

    1981-01-01

    The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

  7. Enhanced bioleaching on attachment of indigenous acidophilic bacteria to pyrite surface

    Science.gov (United States)

    Wi, D. W.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    In recent years, bioleaching has been widely applied on an industrial scale due to the advantages of low cost and environment friendliness. The direct contact mechanism of bioleaching assumes the action of a metal sulfide-attached cell oxidizing the mineral by an enzyme system with oxygen to sulfate and metal cations. Fundamental surface properties of sulfide particles and leaching-bacteria in bioleaching play the key role in the efficiency of this process. The aim of this work is to investigate of direct contact bioleaching mechanism on pyrite through attachment properties between indigenous acidophilic bacteria and pyrite surfaces. The bacteria were obtained from sulfur hot springs, Hatchobaru thermal electricity plant in Japan. And pyrite was collected from mine waste from Gwang-yang abandoned gold mines, Korea. In XRD analyses of the pyrite, x-ray diffracted d-value belong to pyrite was observed. The indigenous acidophilic bacteria grew well in a solution and over the course of incubation pH decreased and Eh increased. In relation to a bacterial growth-curve, the lag phase was hardly shown while the exponential phase was very fast. Bioleaching experiment result was showed that twenty days after the indigenous acidophilic bacteria were inoculated to a pyrite-leaching medium, the bacterial sample had a greater concentration of Fe and Zn than within the control sample. In SEM-EDS analyses, rod-shaped bacteria and round-shaped microbes were well attached to the surface of pyrite. The size of the rod-shaped bacteria ranged from 1.05~1.10 ? to 4.01~5.38 ?. Round-shaped microbes were more than 3.0 ? in diameter. Paired cells of rod-shaped bacteria were attached to the surface of pyrite linearly.

  8. Mycorrhiza helper bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

    2016-10-01

    This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

  9. Influence of extracellular polymeric substances (EPS) on Cd adsorption by bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wei Xing [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Fang Linchuan [Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Cai Peng, E-mail: cp@mail.hzau.edu.cn [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Huang Qiaoyun [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Chen Hao [College of Science, Huazhong Agricultural University, Wuhan 430070 (China); Liang Wei; Rong, Xinming [Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China)

    2011-05-15

    The role of extracellular polymeric substances (EPS) in Cd adsorption by Bacillus subtilis and Pseudomonas putida was investigated using a combination of batch adsorption experiments, potentiometric titrations, Fourier transform infrared spectroscopy (FTIR). An increased adsorption capacity of Cd was observed for untreated bacteria relative to that for EPS-free bacteria. Surface complexation modeling of titration data showed the similar pK{sub a} values of functional groups (carboxyl, phosphate and hydroxyl) between untreated and EPS-free bacteria. However, site concentrations on the untreated bacteria were found to be higher than those on the EPS-free bacteria. FTIR spectra also showed that no significant difference in peak positions was observed between untreated and EPS-free bacteria and carboxyl and phosphate groups were responsible for Cd adsorption on bacterial cells. The information obtained in this study is of fundamental significance for understanding the interaction mechanisms between heavy metals and biofilms in natural environments. - Highlights: > The presence of EPS on bacterial surfaces facilitates the adsorption of Cd. > The promoting effects on Cd adsorption are more remarkable on Gram-positive B. subtilis cells than that on Gram-negative P. putida cells. > Carboxyl and phosphate groups are mostly responsible for Cd binding on untreated and EPS-free cells. > Intact bacterial cells and EPS-free cells have similar binding mechanisms for Cd. - Intact bacterial cells and EPS-free cells have similar binding mechanisms for Cd.

  10. Propionate oxidation by and methanol inhibition of anaerobic ammonium-oxidizing bacteria.

    Science.gov (United States)

    Güven, Didem; Dapena, Ana; Kartal, Boran; Schmid, Markus C; Maas, Bart; van de Pas-Schoonen, Katinka; Sozen, Seval; Mendez, Ramon; Op den Camp, Huub J M; Jetten, Mike S M; Strous, Marc; Schmidt, Ingo

    2005-02-01

    Anaerobic ammonium oxidation (anammox) is a recently discovered microbial pathway and a cost-effective way to remove ammonium from wastewater. Anammox bacteria have been described as obligate chemolithoautotrophs. However, many chemolithoautotrophs (i.e., nitrifiers) can use organic compounds as a supplementary carbon source. In this study, the effect of organic compounds on anammox bacteria was investigated. It was shown that alcohols inhibited anammox bacteria, while organic acids were converted by them. Methanol was the most potent inhibitor, leading to complete and irreversible loss of activity at concentrations as low as 0.5 mM. Of the organic acids acetate and propionate, propionate was consumed at a higher rate (0.8 nmol min(-1) mg of protein(-1)) by Percoll-purified anammox cells. Glucose, formate, and alanine had no effect on the anammox process. It was shown that propionate was oxidized mainly to CO(2), with nitrate and/or nitrite as the electron acceptor. The anammox bacteria carried out propionate oxidation simultaneously with anaerobic ammonium oxidation. In an anammox enrichment culture fed with propionate for 150 days, the relative amounts of anammox cells and denitrifiers did not change significantly over time, indicating that anammox bacteria could compete successfully with heterotrophic denitrifiers for propionate. In conclusion, this study shows that anammox bacteria have a more versatile metabolism than previously assumed.

  11. [Impact of fluoroquinolone use on multidrug-resistant bacteria emergence].

    Science.gov (United States)

    Nseir, S; Ader, F; Marquette, C-H; Durocher, A

    2005-01-01

    During the last two decades, fluoroquinolone use has significantly increased in Europe and in the USA. This could be explained by the arrival of newer fluoroquinolones with antipneumoccal activity. Increased use of fluoroquinolones is associated with higher rates of bacterial resistance to these antibiotics. Resistance of Gram-negative bacilli to fluoroquinolones is increasing in industrialized countries. In addition, fluoroquinolone use has been identified as a risk factor for colonization and infection to methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanni, extending-spectrum beta-lactamase producing Gram negative bacilli, and multidrug-resistant bacteria. Nosocomial infections due to multidrug-resistant bacteria are associated with higher mortality and morbidity rates. This could be related to more frequent inappropriate initial antibiotic treatment in these patients. Limiting the use of fluoroquinolones, limiting the duration of treatment with fluoroquinolones, and using appropriate dosage of these antibiotics could be suggested to reduce resistance to these antibiotics and to reduce the emergence of multidrug-resistant bacteria.

  12. Chlamydia related bacteria (Chlamydiales) in early pregnancy: community-based cohort study.

    Science.gov (United States)

    Reid, F; Oakeshott, P; Kerry, S R; Hay, P E; Jensen, J S

    2017-02-01

    Serological case-control studies suggest that certain chlamydia-related bacteria (Chlamydiales) which cause cows to abort may do the same in humans. Chlamydiales include Waddlia chondrophila, Chlamydia abortus and Chlamydia trachomatis. Data on prevalence of Chlamydiales in pregnancy are sparse. Using stored urine samples from a carefully characterised cohort of 847 newly pregnant women recruited from 37 general practices in London, UK, we aimed to investigate the prevalence and types of Chlamydiales infections. We also explored possible associations with miscarriage or spontaneous preterm birth. Samples were tested using W. chondrophila and pan-Chlamydiales specific real-time PCRs targeting the 16S rRNA gene. Samples positive on either PCR were subjected to DNA sequencing and C. trachomatis PCR. The overall prevalence of Chlamydiales was 4.3% (36/847, 95% CI 3.0% to 5.8%). The prevalence of W. chondrophila was 0.6% (n = 5), C. trachomatis 1.7% (n = 14), and other Chlamydiales species 2.0% (n = 17). Infection with C. trachomatis was more common in women aged <25, of black ethnicity or with bacterial vaginosis, but this did not apply to W. chondrophila or other Chlamydiales. Follow up was 99.9% at 16 weeks gestation and 90% at term. No infection was significantly associated with miscarriage at ≤12 weeks (prevalence 10%, 81/827) or preterm birth <37 weeks (prevalence 4%, 23/628). Of 25 samples sequenced, seven (28%) were positive for Chlamydiales bacterium sequences associated with respiratory tract infections in children. In the first study to use the pan-Chlamydiales assay on female urine samples, 4% of pregnant women tested positive for Chlamydiales, including species known to be pathogenic in mothers and neonates. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Horizontal gene transfer between bacteria.

    Science.gov (United States)

    Heuer, Holger; Smalla, Kornelia

    2007-01-01

    Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

  14. Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

    Science.gov (United States)

    Yulianti, Evy; Rakhmawati, Anna

    2017-08-01

    The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

  15. Deployable micro-traps to sequester motile bacteria

    Science.gov (United States)

    di Giacomo, Raffaele; Krödel, Sebastian; Maresca, Bruno; Benzoni, Patrizia; Rusconi, Roberto; Stocker, Roman; Daraio, Chiara

    2017-04-01

    The development of strategies to reduce the load of unwanted bacteria is a fundamental challenge in industrial processing, environmental sciences and medical applications. Here, we report a new method to sequester motile bacteria from a liquid, based on passive, deployable micro-traps that confine bacteria using micro-funnels that open into trapping chambers. Even in low concentrations, micro-traps afford a 70% reduction in the amount of bacteria in a liquid sample, with a potential to reach >90% as shown by modelling improved geometries. This work introduces a new approach to contain the growth of bacteria without chemical means, an advantage of particular importance given the alarming growth of pan-drug-resistant bacteria.

  16. COMPETITION BETWEEN ANOXYGENIC PHOTOTROPHIC BACTERIA AND COLORLESS SULFUR BACTERIA IN A MICROBIAL MAT

    NARCIS (Netherlands)

    VISSCHER, PT; VANDENENDE, FP; SCHAUB, BEM; VANGEMERDEN, H

    The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for

  17. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

  18. Bacteria transport and retention in intact calcareous soil columns under saturated flow conditions

    Directory of Open Access Journals (Sweden)

    Farrokhian Firouzi Ahmad

    2015-06-01

    Full Text Available Study of bacterial transport and retention in soil is important for various environmental applications such as groundwater contamination and bioremediation of soil and water. The main objective of this research was to quantitatively assess bacterial transport and deposition under saturated conditions in calcareous soil. A series of leaching experiments was conducted on two undisturbed soil columns. Breakthrough curves of Pseudomonas fluorescens and Cl were measured. After the leaching experiment, spatial distribution of bacteria retention in the soil columns was determined. The HYDRUS-1D one- and two-site kinetic models were used to predict the transport and deposition of bacteria in soil. The results indicated that the two-site model fits the observed data better than one-site kinetic model. Bacteria interaction with the soil of kinetic site 1 revealed relatively fast attachment and slow detachment, whereas attachment to and detachment of bacteria from kinetic site 2 was fast. Fast attachment and slow detachment of site 1 can be attributed to soil calcium carbonate that has favorable attachment sites for bacteria. The detachment rate was less than 0.02 of the attachment rate, indicating irreversible attachment of bacteria. High reduction rate of bacteria was also attributed to soil calcium carbonate.

  19. Morphologic characterization and quantitative analysis on in vitro bacteria by nuclear techniques of measurement

    International Nuclear Information System (INIS)

    Lopes, Joana D'Arc Ramos

    2001-10-01

    The great difficulty to identify microorganisms (bacteria) from infectious processes is related to the necessary time to obtain a reliable result, about 72 hours. The purpose of this work is to establish a faster method to characterize bacterial morphologies through the use of neutron radiography, which can take about 5 hours. The samples containing the microorganisms, bacteria with different morphologies, after the appropriate microbiologic procedures were incubated with B 10 for 30 minutes and soon after deposited in a plate of a solid detector of nuclear tracks (SSNTD), denominated CR-39. To obtain the images relative to bacteria, the detector was submitted to the flow of thermal neutrons of the order of 2.2 x 10 5 n/cm 2 .s from the J-9 channel of the Reactor Argonauta (IEN/CNEN). To observe the images from bacteria in each sample under an optical microscope, the sheets were chemically developed. The analysis of the images revealed morphologic differences among the genera (Gram positive from Gram-negative and coccus from bacillus), in samples containing either isolated or mixed bacteria. We thus verified the viability of the technique to achieve morphological characterization of different microorganisms. A quantitative approach seemed also to be feasible with the technique. The whole process took about 2 hours. (author)

  20. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    Directory of Open Access Journals (Sweden)

    DWI SURYANTO

    2010-03-01

    Full Text Available Biological control of plant disease using antagonistic microorganism has been obtaining much attention and implemented for decades. One of the potential microorganisms used in this strategy is chitinolytic bacteria. Utilization of this bacteria ranges from cell life, enzymes, genes, or other metabolites. In this study, we examined the ability of chitinolytic bacteria as a biocontrol agent of Fusarium wilt of red chili (Capsicum annuum L. seedlings. The ability of chitinolytic bacteria to suppress the disease was evaluated by soaking red chili seeds in the bacterial isolates solution for 30 minutes prior seedling. Percentage of seedling of treated chili seed at end of study (4-weeks ranging from 46 to 82.14%. Relative reduction of the seedling damping-off was observed in all bacterial treatment ranged from 28.57 to 60.71%. Furthermore, manifestation of bacterial suppression to Fusarium wilt was also exhibited by increasing of seedling height (ranged from 7.33 to 7.87 cm compared to 6.88 cm and dry-weight (ranged from 2.7 to 4.3 mg compared to 2.3 mg. However, no significant effect was observed in leaf number. Then, from all chitinolytic isolates tested, BK08 was the most potential candidate for biological control agent of Fusarium wilt in chili seedling.

  1. Effect of metalloporphyrins on red autofluorescence from oral bacteria

    NARCIS (Netherlands)

    Volgenant, C.M.C.; van der Veen, M.H.; de Soet, J.J.; ten Cate, J.M.

    2013-01-01

    The aim of this study was to assess the red autofluorescence from bacterial species related to dental caries and periodontitis in the presence of different nutrients in the growth medium. Bacteria were grown anaerobically on tryptic soy agar (TSA) supplemented with nutrients, including

  2. Distribution of Anaerobic Hydrocarbon-Degrading Bacteria in Soils from King George Island, Maritime Antarctica.

    Science.gov (United States)

    Sampaio, Dayanna Souza; Almeida, Juliana Rodrigues Barboza; de Jesus, Hugo E; Rosado, Alexandre S; Seldin, Lucy; Jurelevicius, Diogo

    2017-11-01

    Anaerobic diesel fuel Arctic (DFA) degradation has already been demonstrated in Antarctic soils. However, studies comparing the distribution of anaerobic bacterial groups and of anaerobic hydrocarbon-degrading bacteria in Antarctic soils containing different concentrations of DFA are scarce. In this study, functional genes were used to study the diversity and distribution of anaerobic hydrocarbon-degrading bacteria (bamA, assA, and bssA) and of sulfate-reducing bacteria (SRB-apsR) in highly, intermediate, and non-DFA-contaminated soils collected during the summers of 2009, 2010, and 2011 from King George Island, Antarctica. Signatures of bamA genes were detected in all soils analyzed, whereas bssA and assA were found in only 4 of 10 soils. The concentration of DFA was the main factor influencing the distribution of bamA-containing bacteria and of SRB in the analyzed soils, as shown by PCR-DGGE results. bamA sequences related to genes previously described in Desulfuromonas, Lautropia, Magnetospirillum, Sulfuritalea, Rhodovolum, Rhodomicrobium, Azoarcus, Geobacter, Ramlibacter, and Gemmatimonas genera were dominant in King George Island soils. Although DFA modulated the distribution of bamA-hosting bacteria, DFA concentration was not related to bamA abundance in the soils studied here. This result suggests that King George Island soils show functional redundancy for aromatic hydrocarbon degradation. The results obtained in this study support the hypothesis that specialized anaerobic hydrocarbon-degrading bacteria have been selected by hydrocarbon concentrations present in King George Island soils.

  3. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

    Science.gov (United States)

    Lambrecht, Ellen; Baré, Julie; Chavatte, Natascha; Bert, Wim; Sabbe, Koen

    2015-01-01

    The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed. PMID:26070667

  4. FECAL COLIFORM BACTERIA AND FACTORS RELATED TO ITS GROWTH AT THE SEKOTONG SHALLOW WELLS, WEST NUSA TENGGARA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Doni Marisi Sinaga

    2016-05-01

    Full Text Available Background: The poor sanitation and small numbers of households who own toilet in Sekotong regency may relate to the diarrheal events due to the fecal coliform contamination in drinking water. Aim: This paper aims to provide the concentrations of fecal coliform bacteria in shallow well waters and the factors associated to its growth. Method: Fifteen groundwater samples were collected from 5 shallow wells to provide the concentrations of total fecal coliform bacteria (FC, mercury concentration, inorganic nitrogen compounds (represent as ammonia, nitrate, and nitrite, total phosphorus (TP, dissolved oxygen (D, pH, and salinity. The concentration of the parameters was then compared to the safe limit set by World Health Organization (WHO. Results: The results indicated that the drinking water resources at the Sekotong regency were contaminated by coliform and mercury. One location with low mercury concentration was recorded with E. coli contamination. Residence, agriculture, and animal livestock were subjected as the sources of coliform contamination. Mercury concentrations may inverse the growth of FC. No apparent relationship was found between total phosphorous and inorganic nitrogen compounds to FC growth. However, we recognized the FC growth responded positively to the level of phosphorous in waters, but associated negatively to nitrate concentration. An inverse correlation was also found between coliform survival and salinity in this study. The pH range at 6.05 – 6.50 supported FC survival. Conclusion: The drinking water resources at the Sekotong shallow wells were contaminated by coliform and mercury. It is important for local government to inform drinking water protection and treatment.

  5. Laser-Based Identification of Pathogenic Bacteria

    Science.gov (United States)

    Rehse, Steven J.

    2009-01-01

    Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

  6. Mimicking Seawater For Culturing Marine Bacteria

    DEFF Research Database (Denmark)

    Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

    2015-01-01

    Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

  7. Antibiotic-resistant bacteria in drinking water.

    Science.gov (United States)

    Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

    1981-08-01

    We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

  8. Aptamer-based viability impedimetric sensor for bacteria.

    Science.gov (United States)

    Labib, Mahmoud; Zamay, Anna S; Kolovskaya, Olga S; Reshetneva, Irina T; Zamay, Galina S; Kibbee, Richard J; Sattar, Syed A; Zamay, Tatiana N; Berezovski, Maxim V

    2012-11-06

    The development of an aptamer-based viability impedimetric sensor for bacteria (AptaVISens-B) is presented. Highly specific DNA aptamers to live Salmonella typhimurium were selected via the cell-systematic evolution of ligands by exponential enrichment (SELEX) technique. Twelve rounds of selection were performed; each comprises a positive selection step against viable S. typhimurium and a negative selection step against heat killed S. typhimurium and a mixture of related pathogens, including Salmonella enteritidis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Citrobacter freundii to ensure the species specificity of the selected aptamers. The DNA sequence showing the highest binding affinity to the bacteria was further integrated into an impedimetric sensor via self-assembly onto a gold nanoparticle-modified screen-printed carbon electrode (GNP-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect S. typhimurium down to 600 CFU mL(-1) (equivalent to 18 live cells in 30 μL of assay volume) and distinguish it from other Salmonella species, including S. enteritidis and S. choleraesuis. This report is envisaged to open a new venue for the aptamer-based viability sensing of a variety of microorganisms, particularly viable but nonculturable (VBNC) bacteria, using a rapid, economic, and label-free electrochemical platform.

  9. Ureolytic/Non-Ureolytic Bacteria Co-Cultured Self-Healing Agent for Cementitious Materials Crack Repair

    Directory of Open Access Journals (Sweden)

    Hyeong Min Son

    2018-05-01

    Full Text Available The present study investigated the CaCO3 precipitation performance of ureolytic and non-ureolytic bacteria co-cultured as a self-healing agent for cementitious materials crack repair. Three different inoculum ratios of ureolytic Sporosarcina pasteurii and non-ureolytic Bacillus thuringiensis (10:0, 8:2, or 5:5 were used. The effect of coculturing ureolytic and non-ureolytic bacteria on microbial metabolism was investigated by measuring the rate of growth in urea-containing medium and the rate of NH4+ and CaCO3 production in urea–calcium lactate medium. The self-healing efficiency of co-cultured bacteria was examined by exposing cement mortar specimens with predefined cracks to media containing single urease-producing or co-cultured bacteria. The obtained results provide new findings, where CaCO3 precipitation is improved by co-culturing ureolytic and non-ureolytic bacteria, owing to the relatively faster growth rate of non-ureolytic bacteria. The crack filling rate correlated with the width of crack, in particular, specimens with a smaller crack width showed the faster filling effect, indicating that the crack width can be a dominant factor influencing the CaCO3 precipitation capacity of co-cultured bacteria.

  10. Limno-tolerant bacteria govern nitrate concentration in Mandovi estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Divya, B.; Fernandes, S.O.; Sheelu, G.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    The spatial and temporal abundances of limno-tolerant and halo-tolerant bacteria were investigated in the tide-dominated Mandovi estuary along the west coast of India. These investigations were carried out in relation to various environmental...

  11. Tetrodotoxin-Producing Bacteria: Detection, Distribution and Migration of the Toxin in Aquatic Systems

    Directory of Open Access Journals (Sweden)

    Timur Yu. Magarlamov

    2017-05-01

    Full Text Available This review is devoted to the marine bacterial producers of tetrodotoxin (TTX, a potent non-protein neuroparalytic toxin. In addition to the issues of the ecology and distribution of TTX-producing bacteria, this review examines issues relating to toxin migration from bacteria to TTX-bearing animals. It is shown that the mechanism of TTX extraction from toxin-producing bacteria to the environment occur through cell death, passive/active toxin excretion, or spore germination of spore-forming bacteria. Data on TTX microdistribution in toxic organs of TTX-bearing animals indicate toxin migration from the digestive system to target organs through the transport system of the organism. The role of symbiotic microflora in animal toxicity is also discussed: despite low toxin production by bacterial strains in laboratory conditions, even minimal amounts of TTX produced by intestinal microflora of an animal can contribute to its toxicity. Special attention is paid to methods of TTX detection applicable to bacteria. Due to the complexity of toxin detection in TTX-producing bacteria, it is necessary to use several methods based on different methodological approaches. Issues crucial for further progress in detecting natural sources of TTX investigation are also considered.

  12. Isolation and characterization of biosurfactant producing bacteria from Persian Gulf (Bushehr provenance).

    Science.gov (United States)

    Hassanshahian, Mehdi

    2014-09-15

    Biosurfactants are surface active materials that are produced by some microorganisms. These molecules increase biodegradation of insoluble pollutants. In this study sediments and seawater samples were collected from the coastline of Bushehr provenance in the Persian Gulf and their biosurfactant producing bacteria were isolated. Biosurfactant producing bacteria were isolated by using an enrichment method in Bushnell-Hass medium with diesel oil as the sole carbon source. Five screening tests were used for selection of Biosurfactant producing bacteria: hemolysis in blood agar, oil spreading, drop collapse, emulsification activity and Bacterial Adhesion to Hydrocarbon test (BATH). These bacteria were identified using biochemical and molecular methods. Eighty different colonies were isolated from the collected samples. The most biosurfactant producing isolates related to petrochemical plants of Khark Island. Fourteen biosurfactant producing bacteria were selected between these isolates and 7 isolates were screened as these were predominant producers that belong to Shewanella alga, Shewanella upenei, Vibrio furnissii, Gallaecimonas pentaromativorans, Brevibacterium epidermidis, Psychrobacter namhaensis and Pseudomonas fluorescens. The largest clear zone diameters in oil spreading were observed for G. pentaromativorans strain O15. Also, this strain has the best emulsification activity and reduction of surface tension, suggesting it is the best of thee isolated strains. The results of this study confirmed that there is high diversity of biosurfactant producing bacteria in marine ecosystem of Iran and by application of these bacteria in petrochemical waste water environmental problems can be assisted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Illumina Sequencing Approach to Characterize Thiamine Metabolism Related Bacteria and the Impacts of Thiamine Supplementation on Ruminal Microbiota in Dairy Cows Fed High-Grain Diets.

    Science.gov (United States)

    Pan, Xiaohua; Xue, Fuguang; Nan, Xuemei; Tang, Zhiwen; Wang, Kun; Beckers, Yves; Jiang, Linshu; Xiong, Benhai

    2017-01-01

    The requirements of thiamine in adult ruminants are mainly met by ruminal bacterial synthesis, and thiamine deficiencies will occur when dairy cows overfed with high grain diet. However, there is limited knowledge with regard to the ruminal thiamine synthesis bacteria, and whether thiamine deficiency is related to the altered bacterial community by high grain diet is still unclear. To explore thiamine synthesis bacteria and the response of ruminal microbiota to high grain feeding and thiamine supplementation, six rumen-cannulated Holstein cows were randomly assigned into a replicated 3 × 3 Latin square design trial. Three treatments were control diet (CON, 20% dietary starch, DM basis), high grain diet (HG, 33.2% dietary starch, DM basis) and high grain diet supplemented with 180 mg thiamine/kg DMI (HG+T). On day 21 of each period, rumen content samples were collected at 3 h postfeeding. Ruminal thiamine concentration was detected by high performance liquid chromatography. The microbiota composition was determined using Illumina MiSeq sequencing of 16S rRNA gene. Cows receiving thiamine supplementation had greater ruminal pH value, acetate and thiamine content in the rumen. Principal coordinate analysis and similarity analysis indicated that HG feeding and thiamine supplementation caused a strong shift in bacterial composition and structure in the rumen. At the genus level, compared with CON group, the relative abundances of 19 genera were significantly changed by HG feeding. Thiamine supplementation increased the abundance of cellulolytic bacteria including Bacteroides, Ruminococcus 1, Pyramidobacter, Succinivibrio , and Ruminobacter , and their increases enhanced the fiber degradation and ruminal acetate production in HG+T group. Christensenellaceae R7, Lachnospira, Succiniclasticum , and Ruminococcaceae NK4A214 exhibited a negative response to thiamine supplementation. Moreover, correlation analysis revealed that ruminal thiamine concentration was positively

  14. Illumina Sequencing Approach to Characterize Thiamine Metabolism Related Bacteria and the Impacts of Thiamine Supplementation on Ruminal Microbiota in Dairy Cows Fed High-Grain Diets

    Directory of Open Access Journals (Sweden)

    Xiaohua Pan

    2017-09-01

    Full Text Available The requirements of thiamine in adult ruminants are mainly met by ruminal bacterial synthesis, and thiamine deficiencies will occur when dairy cows overfed with high grain diet. However, there is limited knowledge with regard to the ruminal thiamine synthesis bacteria, and whether thiamine deficiency is related to the altered bacterial community by high grain diet is still unclear. To explore thiamine synthesis bacteria and the response of ruminal microbiota to high grain feeding and thiamine supplementation, six rumen-cannulated Holstein cows were randomly assigned into a replicated 3 × 3 Latin square design trial. Three treatments were control diet (CON, 20% dietary starch, DM basis, high grain diet (HG, 33.2% dietary starch, DM basis and high grain diet supplemented with 180 mg thiamine/kg DMI (HG+T. On day 21 of each period, rumen content samples were collected at 3 h postfeeding. Ruminal thiamine concentration was detected by high performance liquid chromatography. The microbiota composition was determined using Illumina MiSeq sequencing of 16S rRNA gene. Cows receiving thiamine supplementation had greater ruminal pH value, acetate and thiamine content in the rumen. Principal coordinate analysis and similarity analysis indicated that HG feeding and thiamine supplementation caused a strong shift in bacterial composition and structure in the rumen. At the genus level, compared with CON group, the relative abundances of 19 genera were significantly changed by HG feeding. Thiamine supplementation increased the abundance of cellulolytic bacteria including Bacteroides, Ruminococcus 1, Pyramidobacter, Succinivibrio, and Ruminobacter, and their increases enhanced the fiber degradation and ruminal acetate production in HG+T group. Christensenellaceae R7, Lachnospira, Succiniclasticum, and Ruminococcaceae NK4A214 exhibited a negative response to thiamine supplementation. Moreover, correlation analysis revealed that ruminal thiamine concentration was

  15. Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

    Science.gov (United States)

    Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun

    2015-01-01

    Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research. PMID:26068451

  16. BioNLP Shared Task--The Bacteria Track.

    Science.gov (United States)

    Bossy, Robert; Jourde, Julien; Manine, Alain-Pierre; Veber, Philippe; Alphonse, Erick; van de Guchte, Maarten; Bessières, Philippe; Nédellec, Claire

    2012-06-26

    We present the BioNLP 2011 Shared Task Bacteria Track, the first Information Extraction challenge entirely dedicated to bacteria. It includes three tasks that cover different levels of biological knowledge. The Bacteria Gene Renaming supporting task is aimed at extracting gene renaming and gene name synonymy in PubMed abstracts. The Bacteria Gene Interaction is a gene/protein interaction extraction task from individual sentences. The interactions have been categorized into ten different sub-types, thus giving a detailed account of genetic regulations at the molecular level. Finally, the Bacteria Biotopes task focuses on the localization and environment of bacteria mentioned in textbook articles. We describe the process of creation for the three corpora, including document acquisition and manual annotation, as well as the metrics used to evaluate the participants' submissions. Three teams submitted to the Bacteria Gene Renaming task; the best team achieved an F-score of 87%. For the Bacteria Gene Interaction task, the only participant's score had reached a global F-score of 77%, although the system efficiency varies significantly from one sub-type to another. Three teams submitted to the Bacteria Biotopes task with very different approaches; the best team achieved an F-score of 45%. However, the detailed study of the participating systems efficiency reveals the strengths and weaknesses of each participating system. The three tasks of the Bacteria Track offer participants a chance to address a wide range of issues in Information Extraction, including entity recognition, semantic typing and coreference resolution. We found common trends in the most efficient systems: the systematic use of syntactic dependencies and machine learning. Nevertheless, the originality of the Bacteria Biotopes task encouraged the use of interesting novel methods and techniques, such as term compositionality, scopes wider than the sentence.

  17. Energetics and Application of Heterotrophy in Acetogenic Bacteria.

    Science.gov (United States)

    Schuchmann, Kai; Müller, Volker

    2016-07-15

    Acetogenic bacteria are a diverse group of strictly anaerobic bacteria that utilize the Wood-Ljungdahl pathway for CO2 fixation and energy conservation. These microorganisms play an important part in the global carbon cycle and are a key component of the anaerobic food web. Their most prominent metabolic feature is autotrophic growth with molecular hydrogen and carbon dioxide as the substrates. However, most members also show an outstanding metabolic flexibility for utilizing a vast variety of different substrates. In contrast to autotrophic growth, which is hardly competitive, metabolic flexibility is seen as a key ability of acetogens to compete in ecosystems and might explain the almost-ubiquitous distribution of acetogenic bacteria in anoxic environments. This review covers the latest findings with respect to the heterotrophic metabolism of acetogenic bacteria, including utilization of carbohydrates, lactate, and different alcohols, especially in the model acetogen Acetobacterium woodii Modularity of metabolism, a key concept of pathway design in synthetic biology, together with electron bifurcation, to overcome energetic barriers, appears to be the basis for the amazing substrate spectrum. At the same time, acetogens depend on only a relatively small number of enzymes to expand the substrate spectrum. We will discuss the energetic advantages of coupling CO2 reduction to fermentations that exploit otherwise-inaccessible substrates and the ecological advantages, as well as the biotechnological applications of the heterotrophic metabolism of acetogens. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. Pathogenic bacteria in sewage treatment plants as revealed by 454 pyrosequencing.

    Science.gov (United States)

    Ye, Lin; Zhang, Tong

    2011-09-01

    This study applied 454 high-throughput pyrosequencing to analyze potentially pathogenic bacteria in activated sludge from 14 municipal wastewater treatment plants (WWTPs) across four countries (China, U.S., Canada, and Singapore), plus the influent and effluent of one of the 14 WWTPs. A total of 370,870 16S rRNA gene sequences with average length of 207 bps were obtained and all of them were assigned to corresponding taxonomic ranks by using RDP classifier and MEGAN. It was found that the most abundant potentially pathogenic bacteria in the WWTPs were affiliated with the genera of Aeromonas and Clostridium. Aeromonas veronii, Aeromonas hydrophila, and Clostridium perfringens were species most similar to the potentially pathogenic bacteria found in this study. Some sequences highly similar (>99%) to Corynebacterium diphtheriae were found in the influent and activated sludge samples from a saline WWTP. Overall, the percentage of the sequences closely related (>99%) to known pathogenic bacteria sequences was about 0.16% of the total sequences. Additionally, a platform-independent Java application (BAND) was developed for graphical visualization of the data of microbial abundance generated by high-throughput pyrosequencing. The approach demonstrated in this study could examine most of the potentially pathogenic bacteria simultaneously instead of one-by-one detection by other methods.

  19. Bacteria transport through porous media. Annual report, December 31, 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yen, T.F.

    1986-09-01

    The following five chapters in this report have been processed separately for inclusion in the Energy Data Base: (1) theoretical model of convective diffusion of motile and non-motile bacteria toward solid surfaces; (2) interfacial electrochemistry of oxide surfaces in oil-bearing sands and sandstones; (3) effects of sodium pyrophosphate additive on the ''huff and puff''/nutrient flooding MEOR process; (4) interaction of Escherichia coli B, B/4, and bacteriophage T4D with Berea sandstone rock in relation to enhanced oil recovery; and (5) transport of bacteria in porous media and its significance in microbial enhanced oil recovery.

  20. Molecular Structure of Endotoxins from Gram-negative Marine Bacteria: An Update

    Directory of Open Access Journals (Sweden)

    Antonio Molinaro

    2007-09-01

    Full Text Available Marine bacteria are microrganisms that have adapted, through millions of years, to survival in environments often characterized by one or more extreme physical or chemical parameters, namely pressure, temperature and salinity. The main interest in the research on marine bacteria is due to their ability to produce several biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents. Nonetheless, lipopolysaccharides (LPSs, or their portions, from Gram-negative marine bacteria, have often shown low virulence, and represent potential candidates in the development of drugs to prevent septic shock. Besides, the molecular architecture of such molecules is related to the possibility of thriving in marine habitats, shielding the cell from the disrupting action of natural stress factors. Over the last few years, the depiction of a variety of structures of lipids A, core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been given. In particular, here we will examine the most recently encountered structures for bacteria belonging to the genera Shewanella, Pseudoalteromonas and Alteromonas, of the γ-Proteobacteria phylum, and to the genera Flavobacterium, Cellulophaga, Arenibacter and Chryseobacterium, of the Cytophaga- Flavobacterium-Bacteroides phylum. Particular attention will be paid to the chemical features expressed by these structures (characteristic monosaccharides, non-glycidic appendages, phosphate groups, to the typifying traits of LPSs from marine bacteria and to the possible correlation existing between such features and the adaptation, over years, of bacteria to marine environments.

  1. The Microworld of Marine-Bacteria

    DEFF Research Database (Denmark)

    JØRGENSEN, BB

    1995-01-01

    Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse...... metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea hydrothermal vents or along the Pacific coast of South America are presented here as examples....

  2. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

    1981-01-01

    Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author) [pt

  3. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

    number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

  4. Method and apparatus for detecting phycocyanin-pigmented algae and bacteria from reflected light

    Science.gov (United States)

    Vincent, Robert (Inventor)

    2013-01-01

    The present invention relates to a method of detecting phycocyanin algae or bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

  5. Bioenergetics of photoheterotrophic bacteria in the oceans.

    Science.gov (United States)

    Kirchman, David L; Hanson, Thomas E

    2013-04-01

    Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  6. Evolutionary dynamics of bacteria in a human host environment

    DEFF Research Database (Denmark)

    Yang, Lei; Jelsbak, Lars; Marvig, Rasmus Lykke

    2011-01-01

    Laboratory evolution experiments have led to important findings relating organism adaptation and genomic evolution. However, continuous monitoring of long-term evolution has been lacking for natural systems, limiting our understanding of these processes in situ. Here we characterize the evolution...... long-term in vitro evolution experiments. The evolved phenotype of the infecting bacteria further suggests that the opportunistic pathogen has transitioned to become a primary pathogen for cystic fibrosis patients.......Laboratory evolution experiments have led to important findings relating organism adaptation and genomic evolution. However, continuous monitoring of long-term evolution has been lacking for natural systems, limiting our understanding of these processes in situ. Here we characterize...... the evolutionary dynamics of a lineage of a clinically important opportunistic bacterial pathogen, Pseudomonas aeruginosa, as it adapts to the airways of several individual cystic fibrosis patients over 200,000 bacterial generations, and provide estimates of mutation rates of bacteria in a natural environment...

  7. Ecophysiology of the Anammox Bacteria

    NARCIS (Netherlands)

    Kartal, M.B.

    2008-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a

  8. Endophytic Bacteria Suppress Bacterial Wilt of Tomato Caused by Ralstonia solanacearum and Activate Defense-related Metabolites

    Directory of Open Access Journals (Sweden)

    Fahime Safdarpour

    2017-12-01

    Full Text Available Introduction: Phytopathogenic microorganisms affect plant health and burden a major threat to food production and ecosystem stability. Increasing the use of chemical pesticides for plant diseases control causes several negative effects on human and environment health. Furthermore, increasing public awareness about the side effects of them led to a research to find alternatives for these products. One of the alternative methods is bio-control utilizing plant associated antagonistic microorganisms. Materials and methods: In this study, 80 endophytic bacteria were isolated from tomato tissues. Their antagonistic activity screened based on agar diffusion test, against tomato bacterial wilt disease (Ralstonia solanacearum. They were identified based on the morphological, biochemical properties and 16s rRNA sequence analyses. These strains were evaluated in greenhouse and tested for their ability to induce the production of defense-related enzymes in plants e.g. Peroxidase (PO, polyphenoloxidase (PPO and phenolics based on spectrophotometer method. Results: Results showed FS67, FS167 and FS184 strains had maximum inhibition zone forming. They identified as Pseudomonas mossellii, P. fuorescence and P. brassicacearum respectively. FS67 and FS167 strains significantly reduced disease in greenhouse. There was a significant increase in the activity of PO, PPO and phenolics in tomato plants treated with FS67, FS167 and pathogen. Discussion and conclusion: The present study has shown that P. mosselli and P. fuorescence might have the potential to control R. solanacearum. However, the good results obtained in vitro cannot be gained the same as those in greenhouse or field conditions. So, further experiments are needed to determine the effectiveness of these isolates under field conditions.This work support the view that increased defense enzymes activities could be involved, at least in part, in the beneficial effects of endophytic bacteria on plants growth

  9. Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

    Directory of Open Access Journals (Sweden)

    Yanhua Cui

    2015-06-01

    Full Text Available Plasmids are widely distributed in different sources of lactic acid bacteria (LAB as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research.

  10. Electron transport chains of lactic acid bacteria

    NARCIS (Netherlands)

    Brooijmans, R.J.W.

    2008-01-01

    Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic

  11. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided.

  12. Antibacterial Activities of Endophytic Bacteria Isolated from Taxus brevifolia Against Foodborne Pathogenic Bacteria.

    Science.gov (United States)

    Islam, Nurul; Choi, Jaehyuk; Baek, Kwang-Hyun

    2018-05-01

    Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T. brevifolia seed (TbS)-8, T. brevifolia fleshy part of fruit (TbFl)-10, T. brevifolia leaf (TbL)-22, TbS-29, and TbL-34 exerted significant antibacterial activity against the tested foodborne pathogens. Especially TbFl-10 showed the highest antibacterial activity against all the tested bacteria and was identified as Paenibacillus kribbensis (Pk). Furthermore, an ethyl acetate extract of Pk-TbFl-10 possessed antibacterial activities against the tested five foodborne pathogenic bacteria, with zones of inhibition from 15.71 ± 2.85 to 13.01 ± 2.12 mm. Scanning electron microscopy analysis revealed ruptured, lysed, shrunk, and swollen cells of all the tested foodborne pathogens treated with the ethyl acetate extract of Pk-TbFl-10, suggesting that a metabolite(s) of Pk-TbFl-10 penetrates the cell membrane and causes cell lysis leading to cell death. Our results indicate that Pk-TbFl-10 isolated from T. brevifolia can serve as a novel source of natural antibacterial agents against foodborne pathogenic bacteria, with potential applications in the pharmaceutical industry.

  13. Money and transmission of bacteria.

    NARCIS (Netherlands)

    Gedik, H.; Voss, T.A.; Voss, A.

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

  14. Review on SERS of Bacteria

    Directory of Open Access Journals (Sweden)

    Pamela A. Mosier-Boss

    2017-11-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

  15. Using Fluorescent Viruses for Detecting Bacteria in Water

    Science.gov (United States)

    Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

    2009-01-01

    A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

  16. Screening and biological characteristics of fufenozide degrading bacteria

    Science.gov (United States)

    Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao

    2018-04-01

    Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.

  17. HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

    2006-08-15

    Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

  18. Occurrence of tributyltin (TBT)-resistant bacteria is not related to TBT pollution in Mekong River and coastal sediment: with a hypothesis of selective pressure from suspended solid.

    Science.gov (United States)

    Suehiro, Fujiyo; Mochizuki, Hiroko; Nakamura, Shinji; Iwata, Hisato; Kobayashi, Takeshi; Tanabe, Shinsuke; Fujimori, Yoshifumi; Nishimura, Fumitake; Tuyen, Bui Cach; Tana, Touch Seang; Suzuki, Satoru

    2007-07-01

    Tributyltin (TBT) is organotin compound that is toxic to aquatic life ranging from bacteria to mammals. This study examined the concentration of TBT in sediment from and near the Mekong River and the distribution of TBT-resistant bacteria. TBT concentrations ranged from TBT-resistant bacteria ranged TBT-resistant bacteria ranged from TBT in the sediment and of TBT-resistant bacteria were unrelated, and chemicals other than TBT might induce TBT resistance. TBT-resistant bacteria were more abundant in the dry season than in the rainy season. Differences in the selection process of TBT-resistant bacteria between dry and rainy seasons were examined using an advection-diffusion model of a suspended solid (SS) that conveys chemicals. The estimated dilution-diffusion time over a distance of 120 km downstream from a release site was 20 days during dry season and 5 days during rainy season, suggesting that bacteria at the sediment surface could be exposed to SS for longer periods during dry season.

  19. Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

    Science.gov (United States)

    Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

    2015-11-01

    Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_005126 gi|37525549 >1iwlA 1 182 22 203 4e-57 ... ref|NP_928893.1| outer-membrane lipoproteins... ... emb|CAE13895.1| outer-membrane lipoproteins carrier ... protein precursor (P20) [Photorhabdus

  1. Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran.

    Science.gov (United States)

    Mirhoseini, Seyed Hamed; Nikaeen, Mahnaz; Khanahmad, Hossein; Hassanzadeh, Akbar

    2016-01-01

    Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals. A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria. The average level of bacteria ranged from 99 to 1079 CFU/m(3). The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m(3)) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m(3)). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012). Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections.

  2. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

    Directory of Open Access Journals (Sweden)

    Vasconcelos Ana

    2010-02-01

    Full Text Available Abstract Background Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Results Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. Conclusions The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle

  3. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales.

    Science.gov (United States)

    Carvalho, Fabíola M; Souza, Rangel C; Barcellos, Fernando G; Hungria, Mariangela; Vasconcelos, Ana Tereza R

    2010-02-08

    Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle evolution in these microorganisms, although they may act in

  4. Current status and emerging role of glutathione in food grade lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Pophaly Sarang

    2012-08-01

    Full Text Available Abstract Lactic acid bacteria (LAB have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms.

  5. Bacteria-mediated bisphenol A degradation.

    Science.gov (United States)

    Zhang, Weiwei; Yin, Kun; Chen, Lingxin

    2013-07-01

    Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

  6. Fish skin bacteria: Colonial and cellular hydrophobicity.

    Science.gov (United States)

    Sar, N; Rosenberg, E

    1987-05-01

    Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

  7. Bacteria in atmospheric waters: Detection, characteristics and implications

    Science.gov (United States)

    Hu, Wei; Niu, Hongya; Murata, Kotaro; Wu, Zhijun; Hu, Min; Kojima, Tomoko; Zhang, Daizhou

    2018-04-01

    In this review paper, we synthesize the current knowledges about bacteria in atmospheric waters, e.g., cloud, fog, rain, and snow, most of which were obtained very recently. First, we briefly describe the importance of bacteria in atmospheric waters, i.e., the essentiality of studying bacteria in atmospheric waters in understanding aerosol-cloud-precipitation-climate interactions in the Earth system. Next, approaches to collect atmospheric water samples for the detection of bacteria and methods to identify the bacteria are summarized and compared. Then the available data on the abundance, viability and community composition of bacteria in atmospheric waters are summarized. The average bacterial concentration in cloud water was usually on the order 104-105 cells mL-1, while that in precipitation on the order 103-104 cells mL-1. Most of the bacteria were viable or metabolically active. Their community composition was highly diverse and differed at various sites. Factors potentially influencing the bacteria, e.g., air pollution levels and sources, meteorological conditions, seasonal effect, and physicochemical properties of atmospheric waters, are described. After that, the implications of bacteria present in atmospheric waters, including their effect on nucleation in clouds, atmospheric chemistry, ecosystems and public health, are briefly discussed. Finally, based on the current knowledges on bacteria in atmospheric waters, which in fact remains largely unknown, we give perspectives that should be paid attention to in future studies.

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

    Science.gov (United States)

    Erickson, Harold P

    2017-08-01

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

  9. Aspects relating to use of radioactively labelled bacteria in animal experiments. 7

    International Nuclear Information System (INIS)

    Heilmann, P.; Flossmann, K.D.; Mueller, G.; Finsterbusch, L.

    1983-01-01

    Two different types of aerosol dispensers were used in an aerosol compartment to apply 59 Fe-labelled bacteria (Pasteurella multocida) to SPE Mini-LEWE piglets as well as to conventionally raised piglets and calves. Germ intake was verified by detection of radioactivity in the lungs. Antigen deposition on each lung amounted to 2-3 . 10 8 in mini-piglets, 6-8 . 10 8 in ordinary piglets, and 2 . 10 9 in conventionally raised calves, as determined by SAG-1, a Soviet model of aerosol dispenser. More or less equally high concentrations of aerosol particles were retained in the pulmonary lobes, independent of the animal species used. Antigen intake could not be influenced by addition of skim milk or by restriction of germ suspensions. (author)

  10. Coliform Bacteria Monitoring in Fish Systems: Current Practices in Public Aquaria.

    Science.gov (United States)

    Culpepper, Erin E; Clayton, Leigh A; Hadfield, Catherine A; Arnold, Jill E; Bourbon, Holly M

    2016-06-01

    Public aquaria evaluate coliform indicator bacteria levels in fish systems, but the purpose of testing, testing methods, and management responses are not standardized, unlike with the coliform bacteria testing for marine mammal enclosures required by the U.S. Department of Agriculture. An online survey was sent to selected aquaria to document current testing and management practices in fish systems without marine mammals. The information collected included indicator bacteria species, the size and type of systems monitored, the primary purpose of testing, sampling frequency, test methods, the criteria for interpreting results, corrective actions, and management changes to limit human exposure. Of the 25 institutions to which surveys were sent, 19 (76%) responded. Fourteen reported testing for fecal indicator bacteria in fish systems. The most commonly tested indicator species were total (86%) and fecal (79%) coliform bacteria, which were detected by means of the membrane filtration method (64%). Multiple types and sizes of systems were tested, and the guidelines for testing and corrective actions were highly variable. Only three institutions performed additional tests to confirm the identification of indicator organisms. The results from this study can be used to compare bacterial monitoring practices and protocols in fish systems, as an aid to discussions relating to the accuracy and reliability of test results, and to help implement appropriate management responses. Received August 23, 2015; accepted December 29, 2015.

  11. Characterization of spoilage bacteria in pork sausage by PCR-DGGE analysis

    Directory of Open Access Journals (Sweden)

    Francesca Silva Dias

    2013-09-01

    Full Text Available To investigate microbial diversity and identify spoilage bacteria in fresh pork sausages during storage, twelve industrial pork sausages of different trademarks were stored at 4 ºC for 0, 14, 28 and 42 days, 80% relative humidity and packaged in sterile plastic bags. Microbiological analysis was performed. The pH and water activity (a w were measured. The culture-independent method performed was the Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis (PCR-DGGE. The culture-dependent method showed that the populations of mesophilic bacteria and Lactic Acid Bacteria (LAB increased linearly over storage time. At the end of the storage time, the average population of microorganisms was detected, in general, at the level of 5 log cfu g-1. A significant (P < 0.005 increase was observed in pH and a w values at the end of the storage time. The PCR-DGGE allowed a rapid identification of dominant communities present in sausages. PCR-DGGE discriminated 15 species and seven genera of bacteria that frequently constitute the microbiota in sausage products. The most frequent spoilage bacteria identified in the sausages were Lactobacillus sakei and Brochothrix thermosphacta. The identification of dominant communities present in fresh pork sausages can help in the choice of the most effective preservation method for extending the product shelf-life.

  12. DEVELOPMENT OF RESISTANCE IN BACTERIA AGAINST ANTI - MICROBIAL AGENTS: REASONS, THREATS AND ONGOING ENCOUNTER

    OpenAIRE

    Shibabrata Pattanayak

    2011-01-01

    Development of Multi Druug Resistant bacteria is creating a very severe problem in anti-microbial chemotherapy. Many recently developed antibiotics are found incapable to control resistant organisms.The reasons of development of resistance gene in the bacterial plasmid and their quick spread among various related and unrelated bacteria are analysed in this article along with discussion of world wide ongoing research to combat the problem.

  13. Magnetic Bacteria.

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  14. Ecology of mycophagous collimonas bacteria in soil

    NARCIS (Netherlands)

    Höppener-Ogawa, Sachie

    2008-01-01

    Bacteria belonging to the genus Collimonas consist of soil bacteria that can grow at expense of living fungal hyphae i.e. they are mycophagous. This PhD studies deals with the ecology of mycophagous bacteria in soil using collimonads as model organisms. Collimonads were found to be widely

  15. Label and label-free based surface-enhanced Raman scattering for pathogen bacteria detection: A review.

    Science.gov (United States)

    Liu, Yu; Zhou, Haibo; Hu, Ziwei; Yu, Guangxia; Yang, Danting; Zhao, Jinshun

    2017-08-15

    Rapid, accurate detection of pathogen bacteria is a highly topical research area for the sake of food safety and public health. Surface-enhanced Raman scattering (SERS) is being considered as a powerful and attractive technique for pathogen bacteria detection, due to its sensitivity, high speed, comparatively low cost, multiplexing ability and portability. This contribution aims to give a comprehensive overview of SERS as a technique for rapid detection of pathogen bacteria based on label and label-free strategies. A brief tutorial on SERS is given first of all. Then we summarize the recent trends and developments of label and label-free based SERS applied to detection of pathogen bacteria, including the relatively complete interpretation of SERS spectra. In addition, multifunctional SERS platforms for pathogen bacteria in matrix are discussed as well. Furthermore, an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for real-time pathogen bacteria detection are given. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Fourier transform-infrared spectroscopic methods for microbial ecology: analysis of bacteria, bacteria-polymer mixtures and biofilms

    Science.gov (United States)

    Nichols, P. D.; Henson, J. M.; Guckert, J. B.; Nivens, D. E.; White, D. C.

    1985-01-01

    Fourier transform-infrared (FT-IR) spectroscopy has been used to rapidly and nondestructively analyze bacteria, bacteria-polymer mixtures, digester samples and microbial biofilms. Diffuse reflectance FT-IR (DRIFT) analysis of freeze-dried, powdered samples offered a means of obtaining structural information. The bacteria examined were divided into two groups. The first group was characterized by a dominant amide I band and the second group of organisms displayed an additional strong carbonyl stretch at approximately 1740 cm-1. The differences illustrated by the subtraction spectra obtained for microbes of the two groups suggest that FT-IR spectroscopy can be utilized to recognize differences in microbial community structure. Calculation of specific band ratios has enabled the composition of bacteria and extracellular or intracellular storage product polymer mixtures to be determined for bacteria-gum arabic (amide I/carbohydrate C-O approximately 1150 cm-1) and bacteria-poly-beta-hydroxybutyrate (amide I/carbonyl approximately 1740 cm-1). The key band ratios correlate with the compositions of the material and provide useful information for the application of FT-IR spectroscopy to environmental biofilm samples and for distinguishing bacteria grown under differing nutrient conditions. DRIFT spectra have been obtained for biofilms produced by Vibrio natriegens on stainless steel disks. Between 48 and 144 h, an increase in bands at approximately 1440 and 1090 cm-1 was seen in FT-IR spectra of the V. natriegens biofilm. DRIFT spectra of mixed culture effluents of anaerobic digesters show differences induced by shifts in input feedstocks. The use of flow-through attenuated total reflectance has permitted in situ real-time changes in biofilm formation to be monitored and provides a powerful tool for understanding the interactions within adherent microbial consortia.

  17. Effect of the Intelligent Health Messenger Box on health care professionals' knowledge, attitudes, and practice related to hand hygiene and hand bacteria counts.

    Science.gov (United States)

    Saffari, Mohsen; Ghanizadeh, Ghader; Fattahipour, Rasoul; Khalaji, Kazem; Pakpour, Amir H; Koenig, Harold G

    2016-12-01

    We assessed the effectiveness of the Intelligent Health Messenger Box in promoting hand hygiene using a quasiexperimental design. Knowledge, attitudes, and self-reported practices related to hand hygiene as well as hand bacteria counts and amount of liquid soap used were measured. The intervention involved broadcasting preventive audio messages. All outcomes showed significant change after the intervention compared with before. The Intelligent Health Messenger Box can serve as a practical way to improve hand hygiene. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  18. Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria

    Science.gov (United States)

    2015-07-01

    agent (GA). During a reaction the GA generates nucleation sites that promote the formation of bubbles. As the reaction wave passes, the gas pockets...studies have shown iodine producing reactive materials are effective against spore forming bacteria, but are sensitive to the relative humidity in the...testing environment. Results from tests run in relative high humidity environments show a decreased ability of iodine to effectively neutralize

  19. Lipopolysaccharides in diazotrophic bacteria

    OpenAIRE

    Serrato, Rodrigo V.

    2014-01-01

    Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are...

  20. Presence of lactic bacteria in the air of a winery during the vinification period.

    Science.gov (United States)

    Garijo, P; López, R; Santamaría, P; Ocón, E; Olarte, C; Sanz, S; Gutiérrez, A R

    2009-11-30

    In this paper we have studied the presence and evolution in the winery air of the lactic bacteria responsible for malolactic fermentation. Sampling took place during the winemaking process (between September 2007 and July 2008) in a winery from the Rioja appellation in Spain. The results obtained indicated that the presence of these microorganisms in the atmosphere was detected when grapes were entering the winery, while malolactic fermentation was taking place, and when liquid containing bacteria was manipulated. The species and clones of the lactic bacteria identified were also related to those present in the vinification tanks at any given stage of the process.

  1. Ultrasensitive multiplex optical quantification of bacteria in large samples of biofluids

    Science.gov (United States)

    Pazos-Perez, Nicolas; Pazos, Elena; Catala, Carme; Mir-Simon, Bernat; Gómez-de Pedro, Sara; Sagales, Juan; Villanueva, Carlos; Vila, Jordi; Soriano, Alex; García de Abajo, F. Javier; Alvarez-Puebla, Ramon A.

    2016-01-01

    Efficient treatments in bacterial infections require the fast and accurate recognition of pathogens, with concentrations as low as one per milliliter in the case of septicemia. Detecting and quantifying bacteria in such low concentrations is challenging and typically demands cultures of large samples of blood (~1 milliliter) extending over 24–72 hours. This delay seriously compromises the health of patients. Here we demonstrate a fast microorganism optical detection system for the exhaustive identification and quantification of pathogens in volumes of biofluids with clinical relevance (~1 milliliter) in minutes. We drive each type of bacteria to accumulate antibody functionalized SERS-labelled silver nanoparticles. Particle aggregation on the bacteria membranes renders dense arrays of inter-particle gaps in which the Raman signal is exponentially amplified by several orders of magnitude relative to the dispersed particles. This enables a multiplex identification of the microorganisms through the molecule-specific spectral fingerprints. PMID:27364357

  2. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

    Aalbæk, Bent; Bemis, David A.; Schjærff, Mette

    2010-01-01

    This study aims to investigate the occurrence of coryneform bacteria in canine otitis externa. A combined case series and case-control study was carried out to improve the current knowledge on frequency and clinical significance of coryneform bacteria in samples from canine otitis externa. A total...... of 16 cases of otitis externa with involvement of coryneform bacteria were recorded at two referral veterinary hospitals in Denmark and the US, respectively. Coryneform bacteria were identified by partial 16S rRNA gene sequencing. Corynebacterium auriscanis was the most common coryneform species (10...... cases). Small colony variants of this species were also observed. Other coryneform isolates were identified as Corynebacterium amycolatum (3 cases), Corynebacterium freneyi (2 cases) and an Arcanobacterium-like species (1 case). The coryneform bacteria were in all cases isolated together with other...

  3. Bacteria classification using Cyranose 320 electronic nose

    Directory of Open Access Journals (Sweden)

    Gardner Julian W

    2002-10-01

    Full Text Available Abstract Background An electronic nose (e-nose, the Cyrano Sciences' Cyranose 320, comprising an array of thirty-two polymer carbon black composite sensors has been used to identify six species of bacteria responsible for eye infections when present at a range of concentrations in saline solutions. Readings were taken from the headspace of the samples by manually introducing the portable e-nose system into a sterile glass containing a fixed volume of bacteria in suspension. Gathered data were a very complex mixture of different chemical compounds. Method Linear Principal Component Analysis (PCA method was able to classify four classes of bacteria out of six classes though in reality other two classes were not better evident from PCA analysis and we got 74% classification accuracy from PCA. An innovative data clustering approach was investigated for these bacteria data by combining the 3-dimensional scatter plot, Fuzzy C Means (FCM and Self Organizing Map (SOM network. Using these three data clustering algorithms simultaneously better 'classification' of six eye bacteria classes were represented. Then three supervised classifiers, namely Multi Layer Perceptron (MLP, Probabilistic Neural network (PNN and Radial basis function network (RBF, were used to classify the six bacteria classes. Results A [6 × 1] SOM network gave 96% accuracy for bacteria classification which was best accuracy. A comparative evaluation of the classifiers was conducted for this application. The best results suggest that we are able to predict six classes of bacteria with up to 98% accuracy with the application of the RBF network. Conclusion This type of bacteria data analysis and feature extraction is very difficult. But we can conclude that this combined use of three nonlinear methods can solve the feature extraction problem with very complex data and enhance the performance of Cyranose 320.

  4. Quantification of syntrophic fatty acid-beta-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization

    DEFF Research Database (Denmark)

    Hansen, K.W.; Ahring, Birgitte Kiær; Raskin, L.

    1999-01-01

    Small-subunit rRNA sequences were obtained for two saturated fatty acid-beta-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYE, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S, wolfei LYE was closely related...... fatty acid-beta-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria-and methanogens were compared to specific methanogenic activities...

  5. Pathogenic mechanisms of intracellular bacteria.

    Science.gov (United States)

    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  6. Herbivore Oral Secreted Bacteria Trigger Distinct Defense Responses in Preferred and Non-Preferred Host Plants.

    Science.gov (United States)

    Wang, Jie; Chung, Seung Ho; Peiffer, Michelle; Rosa, Cristina; Hoover, Kelli; Zeng, Rensen; Felton, Gary W

    2016-06-01

    Insect symbiotic bacteria affect host physiology and mediate plant-insect interactions, yet there are few clear examples of symbiotic bacteria regulating defense responses in different host plants. We hypothesized that plants would induce distinct defense responses to herbivore- associated bacteria. We evaluated whether preferred hosts (horsenettle) or non-preferred hosts (tomato) respond similarly to oral secretions (OS) from the false potato beetle (FPB, Leptinotarsa juncta), and whether the induced defense triggered by OS was due to the presence of symbiotic bacteria in OS. Both horsenettle and tomato damaged by antibiotic (AB) treated larvae showed higher polyphenol oxidase (PPO) activity than those damaged by non-AB treated larvae. In addition, application of OS from AB treated larvae induced higher PPO activity compared with OS from non-AB treated larvae or water treatment. False potato beetles harbor bacteria that may provide abundant cues that can be recognized by plants and thus mediate corresponding defense responses. Among all tested bacterial isolates, the genera Pantoea, Acinetobacter, Enterobacter, and Serratia were found to suppress PPO activity in tomato, while only Pantoea sp. among these four isolates was observed to suppress PPO activity in horsenettle. The distinct PPO suppression caused by symbiotic bacteria in different plants was similar to the pattern of induced defense-related gene expression. Pantoea inoculated FPB suppressed JA-responsive genes and triggered a SA-responsive gene in both tomato and horsenettle. However, Enterobacter inoculated FPB eliminated JA-regulated gene expression and elevated SA-regulated gene expression in tomato, but did not show evident effects on the expression levels of horsenettle defense-related genes. These results indicate that suppression of plant defenses by the bacteria found in the oral secretions of herbivores may be a more widespread phenomenon than previously indicated.

  7. Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis.

    LENUS (Irish Health Repository)

    Duffy, M

    2012-02-03

    PURPOSE: Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches. METHODS: After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed. RESULTS: Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated. CONCLUSIONS: Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are

  8. Communication among Oral Bacteria

    Science.gov (United States)

    Kolenbrander, Paul E.; Andersen, Roxanna N.; Blehert, David S.; Egland, Paul G.; Foster, Jamie S.; Palmer, Robert J.

    2002-01-01

    Human oral bacteria interact with their environment by attaching to surfaces and establishing mixed-species communities. As each bacterial cell attaches, it forms a new surface to which other cells can adhere. Adherence and community development are spatiotemporal; such order requires communication. The discovery of soluble signals, such as autoinducer-2, that may be exchanged within multispecies communities to convey information between organisms has emerged as a new research direction. Direct-contact signals, such as adhesins and receptors, that elicit changes in gene expression after cell-cell contact and biofilm growth are also an active research area. Considering that the majority of oral bacteria are organized in dense three-dimensional biofilms on teeth, confocal microscopy and fluorescently labeled probes provide valuable approaches for investigating the architecture of these organized communities in situ. Oral biofilms are readily accessible to microbiologists and are excellent model systems for studies of microbial communication. One attractive model system is a saliva-coated flowcell with oral bacterial biofilms growing on saliva as the sole nutrient source; an intergeneric mutualism is discussed. Several oral bacterial species are amenable to genetic manipulation for molecular characterization of communication both among bacteria and between bacteria and the host. A successful search for genes critical for mixed-species community organization will be accomplished only when it is conducted with mixed-species communities. PMID:12209001

  9. Automated radiometric detection of bacteria

    International Nuclear Information System (INIS)

    Waters, J.R.

    1974-01-01

    A new radiometric method called BACTEC, used for the detection of bacteria in cultures or in supposedly sterile samples, was discussed from the standpoint of methodology, both automated and semi-automated. Some of the results obtained so far were reported and some future applications and development possibilities were described. In this new method, the test sample is incubated in a sealed vial with a liquid culture medium containing a 14 C-labeled substrate. If bacteria are present, they break down the substrate, producing 14 CO 2 which is periodically extracted from the vial as a gas and is tested for radioactivity. If this gaseous radioactivity exceeds a threshold level, it is evidence of bacterial presence and growth in the test vial. The first application was for the detection of bacteria in the blood cultures of hospital patients. Data were presented showing typical results. Also discussed were future applications, such as rapid screening for bacteria in urine industrial sterility testing and the disposal of used 14 C substrates. (Mukohata, S.)

  10. DEVELOPMENT OF RESISTANCE IN BACTERIA AGAINST ANTI - MICROBIAL AGENTS: REASONS, THREATS AND ONGOING ENCOUNTER

    Directory of Open Access Journals (Sweden)

    Shibabrata Pattanayak

    2011-07-01

    Full Text Available Development of Multi Druug Resistant bacteria is creating a very severe problem in anti-microbial chemotherapy. Many recently developed antibiotics are found incapable to control resistant organisms.The reasons of development of resistance gene in the bacterial plasmid and their quick spread among various related and unrelated bacteria are analysed in this article along with discussion of world wide ongoing research to combat the problem.

  11. Subsurface associations of Acaryochloris-related picocyanobacteria with oil-utilizing bacteria in the Arabian Gulf water body: promising consortia in oil sediment bioremediation.

    Science.gov (United States)

    Al-Bader, Dhia; Eliyas, Mohamed; Rayan, Rihab; Radwan, Samir

    2013-04-01

    Two picocyanobacterial strains related to Acaryochloris were isolated from the Arabian Gulf, 3 m below the water surface, one from the north shore and the other from the south shore of Kuwait. Both strains were morphologically, ultrastructurally, and albeit to a less extend, phylogenetically similar to Acaryochloris. However, both isolates lacked chlorophyll d and produced instead chlorophyll a, as the major photosynthetic pigment. Both picocyanobacterial isolates were associated with oil-utilizing bacteria in the magnitude of 10(5) cells g(-1). According to their 16S rRNA gene sequences, bacteria associated with the isolate from the north were affiliated to Paenibacillus sp., Bacillus pumilus, and Marinobacter aquaeolei, but those associated with the isolate from the south were affiliated to Bacillus asahii and Alcanivorax jadensis. These bacterial differences were probably due to environmental variations. In batch cultures, the bacterial consortia in the nonaxenic biomass as well as the pure bacterial isolates effectively consumed crude oil and pure aliphatic and aromatic hydrocarbons, including very high-molecular-weight compounds. Water and diethylether extracts from the phototrophic biomass enhanced growth of individual bacterial isolates and their hydrocarbon-consumption potential in batch cultures. It was concluded that these consortia could be promising in bioremediation of hydrocarbon pollutants, especially heavy sediments in the marine ecosystem.

  12. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  13. Anti-Pathogenic Activity of Coral Bacteria Againts White Plaque Disease of Coral Dipsastraea from Tengah Island, Karimunjawa

    Science.gov (United States)

    Imam Muchlissin, Sakti; Sabdono, Agus; Permata W, Diah

    2018-02-01

    Coral disease is main factor of degrading coral reefs, such as White Plaque (WP) disease that cause loss of epidermal tissue of corals. The purposes of this research were to identify the bacteria associated with White Plaque Disease of coral Dipsastraea and to investigate coral bacteria that have antipathogenic potency against White Plaque Disease by Coral Dipsastraea. Sampling was carried out by purposive method in Tengah Island, Karimunjawa on March 2015. Streak method was used to isolate and purify coral bacteria, while overlay and agar diffusion method were used to test antibacterial activity. Identification of selected bacteria was conducted by biochemical and molecular methods. Polyphasic identification of bacteria associated with diseased coral White Plague of Dipsastraea. It is found that TFWP1, TFWP2, TFWP3 and TFWP4 were closely related to Bacillus antracis, Virgibacillus olivae, Virgibacillus salarius and Bacillus mojavensis, respectively. While antipathogen activity bacterial isolates, NM1.3, NM1.8 and NM2.3 were closely related to Pseudoalteromonas flavipulchra, Pseudoalteromonas piscicida, and Vibrio azureus, respectively. Phylogenetic data on microbial community composition in coral will help with the knowledge in the biological control of coral diseases.

  14. Exposure level and distribution characteristics of airborne bacteria and fungi in Seoul metropolitan subway stations.

    Science.gov (United States)

    Kim, Ki Youn; Kim, Yoon Shin; Kim, Daekeun; Kim, Hyeon Tae

    2011-01-01

    The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station.

  15. Aging in bacteria, immortality or not-a critical review.

    Science.gov (United States)

    Gómez, José M G

    2010-12-01

    Bacteria were traditionally thought to have a symmetrical binary fission without a clear distinction between soma and germ-line, being thus considered as immortal biological entities. Yet it has been recently described that bacteria also undergo replicative aging (RA). That is, they exhibit finite replicative abilities under good conditions to growth. The apparently initial indistinguishability of sibling cells after cytokinesis is broken. After division, the daughter cell that inherits the "old" pole present in the "mother cell" progressively exhibits a decline in its proliferative capacity with increasing cell pole age. This is a clear hallmark and phenotypic manifestation of a bona fide RA phenomenon in toto. While the exact molecular mechanism(s) underlying to this lost of replicative potential are not yet fully understood, the "old pole cell" is considered as an aging parent that in a repeatedly manner is able to produce rejuvenated offspring which inherit a resetting of the biological clock. On the order hand, bacteria exhibit in addition to this "mandatory" RA the dubbed conditional senescence (CS). CS is defined as a decline in cellular viability observed in arrested-growing bacteria populations, a phenomenon apparently not related to RA under growing active conditions. To understand bacterial aging, it is necessary to put it within the sociality-multicellularity framework. This is a new conceptual paradigm that expresses the natural reality of the bacterial world. From this more ecological perspective these bacterial aging phenomena probably should represent an insurance/bethedging anticipative survival strategy. This is underpinned in a self-generation of an appropriate level of populational phenotypic diversity. That is, bacterial aging could be considered a communitarian adaptive response to cope with different environmental stresses and threats. I have highlighted the necessity to construct an integrative conceptual framework to achieve a unified view

  16. Screening of antibiotic susceptibility to β-lactam-induced elongation of Gram-negative bacteria based on dielectrophoresis.

    Science.gov (United States)

    Chung, Cheng-Che; Cheng, I-Fang; Chen, Hung-Mo; Kan, Heng-Chuan; Yang, Wen-Horng; Chang, Hsien-Chang

    2012-04-03

    We demonstrate a rapid antibiotic susceptibility test (AST) based on the changes in dielectrophoretic (DEP) behaviors related to the β-lactam-induced elongation of Gram-negative bacteria (GNB) on a quadruple electrode array (QEA). The minimum inhibitory concentration (MIC) can be determined within 2 h by observing the changes in the positive-DEP frequency (pdf) and cell length of GNB under the cefazolin (CEZ) treatment. Escherichia coli and Klebsiella pneumoniae and the CEZ are used as the sample bacteria and antibiotic respectively. The bacteria became filamentous due to the inhibition of cell wall synthesis and cell division and cell lysis occurred for the higher antibiotic dose. According to the results, the pdfs of wild type bacteria decrease to hundreds of kHz and the cell length is more than 10 μm when the bacterial growth is inhibited by the CEZ treatment. In addition, the growth of wild type bacteria and drug resistant bacteria differ significantly. There is an obvious decrease in the number of wild type bacteria but not in the number of drug resistant bacteria. Thus, the drug resistance of GNB to β-lactam antibiotics can be rapidly assessed. Furthermore, the MIC determined using dielectrophoresis-based AST (d-AST) was consistent with the results of the broth dilution method. Utilizing this approach could reduce the time needed for bacteria growth from days to hours, help physicians to administer appropriate antibiotic dosages, and reduce the possibility of the occurrence of multidrug resistant (MDR) bacteria.

  17. Reactivity of the Bacteria-Water Interface: Linking Nutrient Availability to Bacteria-Metal Interactions

    Science.gov (United States)

    Fowle, D. A.; Daughney, C. J.; Riley, J. L.

    2002-12-01

    Identifying and quantifying the controls on metal mobilities in geologic systems is critical in order to understand processes such as global element cycling, metal transport in near-surface water-rock systems, sedimentary diagenesis, and mineral formation. Bacteria are ubiquitous in near-surface water-rock systems, and numerous laboratory and field studies have demonstrated that bacteria can facilitate the formation and dissolution of minerals, and enhance or inhibit contaminant transport. However, despite the growing evidence that bacteria play a key role in many geologic processes in low temperature systems, our understanding of the influence of the local nutrient dynamics of the system of interest on bacteria-metal interactions is limited. Here we present data demonstrating the effectiveness of coupling laboratory experiments with geochemical modeling to isolate the effect of nutrient availability on bacterially mediated proton and metal adsorption reactions. Experimental studies of metal-bacteria interactions were conducted in batch reactors as a function of pH, and solid-solute interactions after growth in a variety of defined and undefined media. Media nutrient composition (C,N,P) was quantified before and after harvesting the cells. Surface complexation models (SCM) for the adsorption reactions were developed by combining sorption data with the results of acid-base titrations, and in some cases zeta potential titrations of the bacterial surface. Our results indicate a clear change in both buffering potential and metal binding capacity of the cell walls of Bacillus subtilis as a function of initial media conditions. Combining current studies with our past studies on the effects of growth phase and others work on temperature dependence on metal adsorption we hope to develop a holistic surface complexation model for quantifying bacterial effects on metal mass transfer in many geologic systems.

  18. [Anaerobic bacteria 150 years after their discovery by Pasteur].

    Science.gov (United States)

    García-Sánchez, José Elías; García-Sánchez, Enrique; Martín-Del-Rey, Ángel; García-Merino, Enrique

    2015-02-01

    In 2011 we celebrated the 150th anniversary of the discovery of anaerobic bacteria by Louis Pasteur. The interest of the biomedical community on such bacteria is still maintained, and is particularly focused on Clostridium difficile. In the past few years important advances in taxonomy have been made due to the genetic, technological and computing developments. Thus, a significant number of new species related to human infections have been characterised, and some already known have been reclassified. At pathogenic level some specimens of anaerobic microflora, that had not been isolated from human infections, have been now isolated in some clinical conditions. There was emergence (or re-emergence) of some species and clinical conditions. Certain anaerobic bacteria have been associated with established infectious syndromes. The virulence of certain strains has increased, and some hypotheses on their participation in certain diseases have been given. In terms of diagnosis, the routine use of MALDI-TOF has led to a shortening of time and a cost reduction in the identification, with an improvement directly related to the improvement of data bases. The application of real-time PCR has been another major progress, and the sequencing of 16srRNA gene and others is currently a reality for several laboratories. Anaerobes have increased their resistance to antimicrobial agents, and the emergence of resistance to carbapenems and metronidazole, and multi-resistance is a current reality. In this situation, linezolid could be an effective alternative for Bacteroides. Fidaxomicin is the only anti-anaerobic agent introduced in the recent years, specifically for the diarrhoea caused by C.difficile. Moreover, some mathematical models have also been proposed in relation with this species. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  19. ORF Alignment: NC_005126 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_005126 gi|37527217 >1b12A 1 247 78 326 7e-74 ... ref|NP_930561.1| Signal peptidase I (SPase I) (Leader...| ... Signal peptidase I (SPase I) (Leader peptidase I) ... [Photorhabdus luminescens subsp. l

  20. Influence of irradiation of bacteria on their thermoresistance

    International Nuclear Information System (INIS)

    Szulc, M.; Stefaniakowa, A.; Tropilo, J.; Stanczak, B.; Peconek, J.; Mierzewska, H.; Bielecka, J.

    1979-01-01

    The influence of x-radiation on thermoresistance of bacteria was determined. The studies were carried out on: E. coli, Pr. vulgaris, S. typhimurium, Staph. aureus and Str. faecalis. The bacteria were irradiated in PBS (physiological buffer solution) and in broth (containing about 1% of protein) with x-rays at radium absorbed doses of 100, 1000, 5000 and 10 000, which was followed immediately by heating at temperatures causing death of part of the bacteria. The results obtained indicate that irradiation of bacteria with small x-ray doses distinctly decreases their thermoresistance. Synergetic action of irradiation and heating of bacteria was observed, increasing with increased irradiation dose. The greatest changes of thermoresistance occurred with Pr. vulgaris, the smallest with S. typhimurium. Thermoresistance of bacteria decreased more strongly on their irradiation in protein-free medium (PBS). (author)

  1. Concentrations of Staphylococcus species in indoor air as associated with other bacteria, season, relative humidity, air change rate, and S. aureus-positive occupants.

    Science.gov (United States)

    Madsen, Anne Mette; Moslehi-Jenabian, Saloomeh; Islam, Md Zohorul; Frankel, Mika; Spilak, Michal; Frederiksen, Margit W

    2018-01-01

    The aim of this study was to obtain knowledge about concentrations of Staphylococcus aureus, MRSA (methicillin-resistant S. aureus), and other Staphylococcus species in indoor air in Greater Copenhagen and about factors affecting the concentrations. The effects of season, temperature, relative humidity, air change rate (ACR), other bacterial genera, area per occupant, and presence of S. aureus-positive occupants were studied. In samples from 67 living rooms, S. hominis, S. warneri, S. epidermidis, and S. capitis were found in 13-25%; S. saprophyticus, S. cohnii, and S. pasteuri in 5-10%; and S. lugdunensis, S. haemolyticus, S. caprae, S. equorum, S. kloosii, S. pettenkoferi, S. simulans, and S. xylosus in less than 3%. Staphylococcus aureus were found in two of 67 living rooms: spa type t034 (an MRSA) was recovered from a farmhouse, while spa type t509 was found in an urban home. Two species, S. equorum and S. kloosii, were found only in the farmhouse. Staphylococcus was significantly associated with season with lowest concentration and richness in winter. Genera composition was associated with ACR with smaller fractions of Staphylococcus at higher ACR, while richness was significantly and negatively associated with area per occupant. Concentration of Staphylococcus correlated positively with the total concentration of bacteria, but negatively with the total concentration of other bacteria. The concentration of Staphylococcus was not significantly associated with concentrations of the other abundant genera Bacillus, Kocuria, and Micrococcus. In offices with S. aureus-positive occupants, airborne S. aureus was not found. In conclusion, Staphylococcus species constitute a considerable proportion of the airborne bacteria in the studied homes and offices. However, both S. aureus and MRSA had very low prevalence during all seasons. Thus, transmission of S. aureus and MRSA through the air in living rooms in Copenhagen is expected to be limited. The negative associations

  2. Bacterial corrosion in low-temperature geothermal. Mechanisms of corrosion by sulphate-reducing bacteria

    International Nuclear Information System (INIS)

    Daumas, Sylvie

    1987-01-01

    Within the frame of researches aimed at determining the causes of damages noticed on geothermal equipment, this research thesis aims at assessing the respective importance of physical-chemical processes and bacterial intervention in corrosion phenomena. It proposes an ecological approach of the fluid sampled in the Creil geothermal power station. The aim is to define the adaptation and activity degree of isolated sulphate-reducing bacteria with respect to their environment conditions. The author studied the effect of the development of these bacteria on the corrosion of carbon steel used in geothermal. Thus, he proposes a contribution to the understanding of mechanisms related to iron attack by these bacteria. Electrochemical techniques have been adapted to biological processes and used to measure corrosion [fr

  3. Hyphae colonizing bacteria associated with Penicillium bilaii

    DEFF Research Database (Denmark)

    Ghodsalavi, Behnoushsadat

    shown that mycorrhizal helper bacteria presenting in mycorrhizal fungi could stimulate fungal growth, promote establishment of root-fungus symbiosis and enhance plant production. But it is unknown if the comparable relationship exist between the non-mycorrhizal fungus P. bilaii and its hyphae associated...... bacteria. In the current PhD thesis, we assumed that hyphae-associated microbiome of P. bilaii might harbor helper bacteria with ability to improve fungal growth and P solubilization performance. Therefore, we aimed to isolate bacteria associated with the P. bilaii hyphae and identify the fungal growth...... stimulating bacteria with the perspective of promoting efficiency of Jumpstart in soil – plant system. For this purpose, most of the work within the current project was carried out by development of suitable model systems by mimicking the natural soil habitat to reach to the reliable performance in soil...

  4. Bacteria Culture Test: MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/bacteriaculturetest.html Bacteria Culture Test To use the sharing features on this page, please enable JavaScript. What is a Bacteria Culture Test? Bacteria are a large group of ...

  5. Analytic Method on Characteristic Parameters of Bacteria in Water by Multiwavelength Transmission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yuxia Hu

    2017-01-01

    Full Text Available An analytic method together with the Mie scattering theory and Beer-Lambert law is proposed for the characteristic parameter determination of bacterial cells (Escherichia coli 10389 from multiwavelength transmission spectroscopy measurements. We calculate the structural parameters of E. coli cells, and compared with the microscopy, the relative error of cell volume is 7.90%, the cell number is compared with those obtained by plate counting, the relative error is l.02%, and the nucleic content and protein content of single E. coli cells are consistent with the data reported elsewhere. The proposed method can obtain characteristic parameters of bacteria as an excellent candidate for the rapid detection and identification of bacteria in the water.

  6. Putative periodontopathic bacteria and herpesviruses in pregnant women: a case-control study.

    Science.gov (United States)

    Lu, Haixia; Zhu, Ce; Li, Fei; Xu, Wei; Tao, Danying; Feng, Xiping

    2016-06-15

    Little is known about herpesvirus and putative periodontopathic bacteria in maternal chronic periodontitis. The present case-control study aimed to explore the potential relationship between putative periodontopathic bacteria and herpesviruses in maternal chronic periodontitis.Saliva samples were collected from 36 pregnant women with chronic periodontitis (cases) and 36 pregnant women with healthy periodontal status (controls). Six putative periodontopathic bacteria (Porphyromonas gingivalis [Pg], Aggregatibacer actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Prevotella intermedia [Pi], Tannerella forsythia [Tf], and Treponema denticola [Td]) and three herpesviruses (Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], and herpes simplex virus [HSV]) were detected. Socio-demographic data and oral health related behaviors, and salivary estradiol and progesterone levels were also collected. The results showed no significant differences in socio-demographic background, oral health related behaviors, and salivary estradiol and progesterone levels between the two groups (all P > 0.05). The detection rates of included periodontopathic microorganisms were not significantly different between the two groups (all P > 0.05), but the coinfection rate of EBV and Pg was significantly higher in the case group than in the control group (P = 0.028). EBV and Pg coinfection may promote the development of chronic periodontitis among pregnant women.

  7. Using Calculus to Model the Growth of L. Plantarum Bacteria

    Directory of Open Access Journals (Sweden)

    Erin Carey

    2009-01-01

    Full Text Available Experimental data for the growth of Lactobacillus plantarum bacteria have been obtained over time, creating the need for mathematical means to model this data. We use the Gompertz model because it is a sigmoid function for a time series, where growth is slowest at the start and end of a time period. The Gompertz model is especially useful because it defines specific parameters that characterize the S-shaped curve. In addition, the Gompertz model uses relative growth, which is the logarithm of the given population compared to the initial population. This reflects the fact that bacteria grow exponentially. The important parameters that were found were the lag time and the asymptote.

  8. Chemically enhanced sunlight for killing bacteria

    International Nuclear Information System (INIS)

    Block, S.S.; Goswami, D.Y.

    1995-01-01

    Solar ultraviolet (UV) photocatalyzed oxidation of chemicals with titanium dioxide (TiO 2 ) has received considerable attention. Much less recognized, however, is the ability of the same system to destroy bacteria. This study examined this phenomenon and the conditions that affect it. Bacteria in aqueous solution were given solar exposure with titanium dioxide and their survival with time was determined. Lamps with a predominantly solar ultraviolet spectrum were also used in the experiments. Without exposure to UV light, TiO 2 had no deleterious effect on the bacteria. However, several common bacteria on solar exposure in the presence of TiO 2 were killed in just a few minutes, whereas without TiO 2 it took over an hour to destroy them. A concentration of 0.01% TiO 2 was most effective in killing bacteria and 10-fold concentrations lower or higher were successively less effective. Inorganic and organic compounds in solution, even in small amounts, interfered with the efficiency of killing. Alkaline solution also reduced the bactericidal activity. Circulation and agitation provided by stirring to keep the TiO 2 particles suspended reduced the time necessary to kill the bacteria. Time-intensity curves for killing bacteria were the same general shape with or without TiO 2 , indicating that TiO 2 served merely as a catalyst to increase the rate of the reaction but that the mechanism of action was not changed. The shape of the curves show that the organisms are sensitized with a minimum intensity of radiation and that an increase doesn't greatly increase the rate of kill. Below this critical intensity, however, the time required for killing markedly increases as the intensity is decreased

  9. The use of {sup 13}C labelling of bacterial lipids in the characterisation of ambient methane-oxidising bacteria in soils

    Energy Technology Data Exchange (ETDEWEB)

    Crossman, Z.M.; Evershed, R.P. [Bristol Univ., Organic Geochemistry Unit, Biogeochemistry Research Centre, Bristol (United Kingdom); Ineson, P. [York Univ., Dept. of Biology, York (United Kingdom)

    2005-05-15

    The occurrence of methane-oxidising bacteria in soils has received increasing attention because of their role as a sink for atmospheric methane. However, such bacteria are not amenable to modern culturing techniques and hence the widespread interest in the development of methods of cultivation-independent analysis. In the following investigation, a combination of stable isotope labelling with phospholipid fatty acid (PLFA) and bacteriohopanoid analysis was employed in an effort to characterise this functional group of bacteria. Results suggest a novel population of methane-oxidising bacteria related to type II culturable methanotrophs, in particular, the Methylocapsa and Methylocella genera of bacteria. (Author)

  10. Molecular analysis of deep subsurface bacteria

    International Nuclear Information System (INIS)

    Jimenez Baez, L.E.

    1989-09-01

    Deep sediments samples from site C10a, in Appleton, and sites, P24, P28, and P29, at the Savannah River Site (SRS), near Aiken, South Carolina were studied to determine their microbial community composition, DNA homology and mol %G+C. Different geological formations with great variability in hydrogeological parameters were found across the depth profile. Phenotypic identification of deep subsurface bacteria underestimated the bacterial diversity at the three SRS sites, since bacteria with the same phenotype have different DNA composition and less than 70% DNA homology. Total DNA hybridization and mol %G+C analysis of deep sediment bacterial isolates suggested that each formation is comprised of different microbial communities. Depositional environment was more important than site and geological formation on the DNA relatedness between deep subsurface bacteria, since more 70% of bacteria with 20% or more of DNA homology came from the same depositional environments. Based on phenotypic and genotypic tests Pseudomonas spp. and Acinetobacter spp.-like bacteria were identified in 85 million years old sediments. This suggests that these microbial communities might have been adapted during a long period of time to the environmental conditions of the deep subsurface

  11. Overlapping riboflavin supply pathways in bacteria.

    Science.gov (United States)

    García-Angulo, Víctor Antonio

    2017-03-01

    Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.

  12. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    Cohen, D.; Michel, J.; Ferne, M.; Bergner-Rabinowitz, S.; Ginsburg, I.

    1979-01-01

    Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites

  13. Bacteria abundance and diversity of different life stages of Plutella xylostella (Lepidoptera: Plutellidae), revealed by bacteria culture-dependent and PCR-DGGE methods.

    Science.gov (United States)

    Lin, Xiao-Li; Pan, Qin-Jian; Tian, Hong-Gang; Douglas, Angela E; Liu, Tong-Xian

    2015-03-01

    Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella. © 2013 Institute of Zoology, Chinese Academy of Sciences.

  14. Labelling of bacteria with indium chelates

    International Nuclear Information System (INIS)

    Kleinert, P.; Pfister, W.; Endert, G.; Sproessig, M.

    1985-01-01

    The indium chelates were prepared by reaction of radioactive indiumchloride with 10 μg oxine, 15 μg tropolone and 3 mg acetylacetone, resp. The formed chelates have been incubated with 10 9 germs/ml for 5 minutes, with labelling outputs from 90 to 95%. Both gram-positive (Streptococcus, Staphylococcus) and gram-negative bacteria (Escherichia coli) can be labelled. The reproductive capacity of the bacteria was not impaired. The application of indium labelled bacteria allows to show the distribution of microorganisms within the living organism and to investigate problems of bacterial adherence. (author)

  15. Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

    Science.gov (United States)

    Huh, Keon; Oh, Darong; Son, Seok Young; Yoo, Hyung Jung; Song, Byeonghwa; Cho, Dong-il Dan; Seo, Jong-Mo; Kim, Sung Jae

    2016-12-01

    The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be 5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

  16. Community Composition and Abundance of Anammox Bacteria in Cattail Rhizosphere Sediments at Three Phenological Stages.

    Science.gov (United States)

    Zhou, Xiaohong; Zhang, Jinping; Wen, Chunzi

    2017-11-01

    The distribution of anammox bacteria in rhizosphere sediments of cattail (Typha orientalis) at different phenological stages was investigated. Results showed that the number of 16S rRNA gene copies of the anammox bacteria was considerably higher in the rhizosphere sediment than in the nonrhizosphere sediment and control sediment. The abundances of the anammox bacteria exhibited striking temporal variations in the three different cattail phenological stages. In addition, the Chao1 and Shannon H indexes of the anammox bacteria in cattail rhizosphere sediments had evident spatial and temporal variations at different phenological stages. Four anammox genera (Brocadia, Kuenenia, Jettenia, and a new cluster) were detected and had proportions of 34.18, 45.57, 0.63, and 19.62%, respectively. The CCA analysis results indicated that Cu, TN, Pb, and Zn were pivotal factors that affect anammox bacteria composition. The PCoA analysis results indicated that the community structure at the rhizosphere and nonrhizosphere sediments collected on July was relatively specific and was different from sediments collected on other months, suggesting that cattail can influence the community structures of the anammox bacteria at the maturity stage.

  17. The isolation, enumeration, and characterization of Rhizobium bacteria of the soil in Wamena Biological Garden

    Directory of Open Access Journals (Sweden)

    SRI PURWANINGSIH

    2005-04-01

    Full Text Available The eleven soil samples have been isolated and characterized. The aims of the study were to get the pure culture and some data which described about enumeration and especially their characters in relation to the acids and bases reaction in their growth. The isolation of the bacteria use Yeast Extract Mannitol Agar medium (YEMA while the characterization by using YEMA medium mixed with Brom Thymol Blue and Congo Red indicators respectively. The results showed that eighteen isolates have been isolated which consisted of three low growing and fifteen fast growing bacteria. Two isolates were not indicated Rhizobium and sixteen were Rhizobium. Density of Rhizobium enumeration was varied which related to soil organic matter content. The enumeration bacteria in YEMA medium were in the range of 0.6 x 105 and 11.6 x 105 CFU /g soil. The highest population was found in soil sample of Wieb vegetation.

  18. Spatial Variability of Cyanobacteria and Heterotrophic Bacteria in Lake Taihu (China).

    Science.gov (United States)

    Qian, Haifeng; Lu, Tao; Song, Hao; Lavoie, Michel; Xu, Jiahui; Fan, Xiaoji; Pan, Xiangliang

    2017-09-01

    Cyanobacterial blooms frequently occur in Lake Taihu (China), but the intertwined relationships between biotic and abiotic factors modulating the frequency and duration of the blooms remain enigmatic. To better understand the relationships between the key abiotic and biotic factors and cyanobacterial blooms, we measured the abundance and diversity of prokaryotic organisms by high-throughput sequencing, the abundance of key genes involved in microcystin production and nitrogen fixation or loss as well as several physicochemical parameters at several stations in Lake Taihu during a cyanobacterial bloom of Microcystis sp.. Measurements of the copy number of denitrification-related genes and 16S rRNA analyses show that denitrification potential and denitrifying bacteria abundance increased in concert with non-diazotrophic cyanobacteria (Microcystis sp.), suggesting limited competition between cyanobacteria and heterotrophic denitrifiers for nutrients, although potential bacteria-mediated N loss may hamper Microcystis growth. The present study provides insight into the importance of different abiotic and biotic factors in controlling cyanobacteria and heterotrophic bacteria spatial variability in Lake Taihu.

  19. Lipoquinones of some spore-forming rods, lactic-acid bacteria and actinomycetes.

    Science.gov (United States)

    Hess, A; Holländer, R; Mannheim, W

    1979-11-01

    The respiratory quinones of 73 strains of Gram-positive bacteria including spore-forming rods, lactic-acid bacteria and actinomyctes were examined. Menaquinones with seven isoprenoid units (MK-7) were the main quinone type found in representatives of the genus Bacillus and in Sporolactobacillus inulinus. However, a strain of B. thuringiensis produced MK-8 in addition to MK-7, and strains of B. lentus and B. pantothenticus appeared to produce MK-9 and MK-8, respectively, with no MK-7. In the clostridia and lactic-acid bacteria, no quinones were found, except in Pediococcus cerevisiae NCTC 8066 and Lactobacillus casei subsp. rhamnosus ATCC 7469, which contained menaquinones, and Streptococcus faecalis NCTC 775 and HIM 478-1, which contained demethylmenaquinones, in relatively low concentrations. Menaquinones were also found in the actinomycetes (except Actinomyces odontolyticus and Bifidobacterium bifidum which did not produce any quinones) and in Protaminobacter alboflavus ATCC 8458, the so-called Actinobacillus actinoides ATCC 15900 and Noguchia granulosis NCTC 10559.

  20. [Application of anaerobic bacteria detection in oral and maxillofacial infection].

    Science.gov (United States)

    Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

    2016-02-18

    To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

  1. On-chip immunomagnetic separation of bacteria by in-flow dynamic manipulation of paramagnetic beads

    Science.gov (United States)

    Ahmed, Shakil; Noh, Jong Wook; Hoyland, James; de Oliveira Hansen, Roana; Erdmann, Helmut; Rubahn, Horst-Günter

    2016-11-01

    Every year, millions of people all over the world fall ill due to the consumption of unsafe food, where consumption of contaminated and spoiled animal origin product is the main cause for diseases due to bacterial growth. This leads to an intense need for efficient methods for detection of food-related bacteria. In this work, we present a method for integration of immunomagnetic separation of bacteria into microfluidic technology by applying an alternating magnetic field, which manipulates the paramagnetic beads into a sinusoidal path across the whole microchannel, increasing the probability for bacteria capture. The optimum channel geometry, flow rate and alternating magnetic field frequency were investigated, resulting in a capture efficiency of 68 %.

  2. Review on Nano SeleniumProduced by Bacteria

    Directory of Open Access Journals (Sweden)

    LI Ji-xiang

    2014-12-01

    Full Text Available Selenium (Se is a kind of essential trace element for people and animal, while ionic state of selenium is toxic with high concentrations and will cause the selenium pollution. Nano-selenium is stable, nontoxic with higher biological activity. Application of bacteria reducing selenite or selenate to biological nano-selenium has great potential in selenium pollution control and nano-selenium production. This review summarizes the research progress of the red elemental nano-selenium reduced by bacteria including characteristics and application of nano-selenium, effects of carbon and nitrogen source, oxygen, temperature and pH in bacteria nano-selenium production, and molecular mechanisms of nano-selenium reduced by bacteria.

  3. Host gut-derived probiotic bacteria promote hypertrophic muscle progression and upregulate growth-related gene expression of slow-growing Malaysian Mahseer Tor tambroides

    Directory of Open Access Journals (Sweden)

    Md Asaduzzaman

    2018-02-01

    Full Text Available In modern aquaculture, dietary supplementation of probiotics is a novel approach for enhancing growth performance of slow-growing fish. However, the actual role of probiotics in regulating muscle growth at cellular and molecular levels in fish still needs to be clarified. In this study, we hypothesized that host gut derived probiotic bacteria would enhance cellular muscle growth, and upregulate growth-related gene expression in slow-growing Malaysian mahseer Tor tambroides. Therefore, three host-associated probiotics (Bacillus sp. AHG22, Alcaligenes sp. AFG22, and Shewanella sp. AFG21 were isolated from the gastro-intestinal tract of T. tambroides and screened based on their digestive enzyme activity. A fishmeal and casein based control diet (40% crude protein and 10% lipid was formulated, and three different probiotic supplemented diets were prepared by immersing the control diet in each isolated host-derived bacteria, suspended in sterile phosphate buffered saline (PBS, to achieve a final concentration of approximately 1.0 × 108 CFU g−1 feed. Triplicate groups of T. tambroides juveniles (initial weight 1.39 ± 0.06 g were stocked in twelve glass aquaria (100 L capacity with stocking density of 20 individuals per aquarium. The feed was applied twice daily at 3.0% of the fish body weight per day for 90 days. Growth performance (weight gain and specific growth rate of T. tambroides juveniles were significantly higher in Alcaligenes sp. AFG22 and Bacillus sp. AHG22 supplemented diet treatments. Muscle morphometric analysis revealed that dietary supplementation of host-associated probiotic bacteria did not influence the frequency distribution of hyperplastic (class 10 small diameter fibers (≤10 μm. However, hypertrophic (Class 50, Class 60 and Class 70 large diameter fibers (>50 μm were significantly higher in Alcaligenes sp. AFG22 and Bacillus sp. AHG22 supplemented treatments, indicating that increased growth rate of T

  4. Meta-Analysis of Quantification Methods Shows that Archaea and Bacteria Have Similar Abundances in the Subseafloor

    Science.gov (United States)

    May, Megan K.; Kevorkian, Richard T.; Steen, Andrew D.

    2013-01-01

    There is no universally accepted method to quantify bacteria and archaea in seawater and marine sediments, and different methods have produced conflicting results with the same samples. To identify best practices, we compiled data from 65 studies, plus our own measurements, in which bacteria and archaea were quantified with fluorescent in situ hybridization (FISH), catalyzed reporter deposition FISH (CARD-FISH), polyribonucleotide FISH, or quantitative PCR (qPCR). To estimate efficiency, we defined “yield” to be the sum of bacteria and archaea counted by these techniques divided by the total number of cells. In seawater, the yield was high (median, 71%) and was similar for FISH, CARD-FISH, and polyribonucleotide FISH. In sediments, only measurements by CARD-FISH in which archaeal cells were permeabilized with proteinase K showed high yields (median, 84%). Therefore, the majority of cells in both environments appear to be alive, since they contain intact ribosomes. In sediments, the sum of bacterial and archaeal 16S rRNA gene qPCR counts was not closely related to cell counts, even after accounting for variations in copy numbers per genome. However, qPCR measurements were precise relative to other qPCR measurements made on the same samples. qPCR is therefore a reliable relative quantification method. Inconsistent results for the relative abundance of bacteria versus archaea in deep subsurface sediments were resolved by the removal of CARD-FISH measurements in which lysozyme was used to permeabilize archaeal cells and qPCR measurements which used ARCH516 as an archaeal primer or TaqMan probe. Data from best-practice methods showed that archaea and bacteria decreased as the depth in seawater and marine sediments increased, although archaea decreased more slowly. PMID:24096423

  5. Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review.

    Science.gov (United States)

    Fujiyoshi, So; Tanaka, Daisuke; Maruyama, Fumito

    2017-01-01

    Human health is influenced by various factors including microorganisms present in built environments where people spend most of their lives (approximately 90%). It is therefore necessary to monitor and control indoor airborne microbes for occupational safety and public health. Most studies concerning airborne microorganisms have focused on fungi, with scant data available concerning bacteria. The present review considers papers published from 2010 to 2017 approximately and factors affecting properties of indoor airborne bacteria (communities and concentration) with respect to temporal perspective and to multiscale interaction viewpoint. From a temporal perspective, bacterial concentrations in built environments change depending on numbers of human occupancy, while properties of bacterial communities tend to remain stable. Similarly, the bacteria found in social and community spaces such as offices, classrooms and hospitals are mainly associated with human occupancy. Other major sources of indoor airborne bacteria are (i) outdoor environments, and (ii) the building materials themselves. Indoor bacterial communities and concentrations are varied with varying interferences by outdoor environment. Airborne bacteria from the outdoor environment enter an indoor space through open doors and windows, while indoor bacteria are simultaneously released to the outer environment. Outdoor bacterial communities and their concentrations are also affected by geographical factors such as types of land use and their spatial distribution. The bacteria found in built environments therefore originate from any of the natural and man-made surroundings around humans. Therefore, to better understand the factors influencing bacterial concentrations and communities in built environments, we should study all the environments that humans contact as a single ecosystem. In this review, we propose the establishment of a standard procedure for assessing properties of indoor airborne bacteria using

  6. Transmission of Airborne Bacteria across Built Environments and Its Measurement Standards: A Review

    Directory of Open Access Journals (Sweden)

    So Fujiyoshi

    2017-11-01

    bacteria using four factors: temperature, relative humidity (RH, air exchange rate, and occupant density, as a minimum requirement. We also summarize the relevant legislation by country. Choice of factors to measure remain controversial are discussed.

  7. Cuticular bacteria appear detrimental to social spiders in mixed but not monoculture exposure

    Science.gov (United States)

    Keiser, Carl N.; Shearer, Taylor A.; DeMarco, Alexander E.; Brittingham, Hayley A.; Knutson, Karen A.; Kuo, Candice; Zhao, Katherine; Pruitt, Jonathan N.

    2016-01-01

    Abstract Much of an animal’s health status, life history, and behavior are dictated by interactions with its endogenous and exogenous bacterial communities. Unfortunately, interactions between hosts and members of their resident bacterial community are often ignored in animal behavior and behavioral ecology. Here, we aim to identify the nature of host–microbe interactions in a nonmodel organism, the African social spider Stegodyphus dumicola. We collected and identified bacteria from the cuticles of spiders in situ and then exposed spiders to bacterial monocultures cultures via topical application or injection. We also topically inoculated spiders with a concomitant “cocktail” of bacteria and measured the behavior of spiders daily for 24 days after inoculation. Lastly, we collected and identified bacteria from the cuticles of prey items in the capture webs of spiders, and then fed spiders domestic crickets which had been injected with these bacteria. We also injected 1 species of prey-borne bacteria into the hemolymph of spiders. Only Bacillus thuringiensis caused increased mortality when injected into the hemolymph of spiders, whereas no bacterial monocultures caused increased mortality when applied topically, relative to control solutions. However, a bacterial cocktail of cuticular bacteria caused weight loss and mortality when applied topically, yet did not detectibly alter spider behavior. Consuming prey injected with prey-borne bacteria was associated with an elongated lifespan in spiders. Thus, indirect evidence from multiple experiments suggests that the effects of these bacteria on spider survivorship appear contingent on their mode of colonization and whether they are applied in monoculture or within a mixed cocktail. We urge that follow-up studies should test these host–microbe interactions across different social contexts to determine the role that microbes play in colony performance. PMID:29491926

  8. Differential staining of bacteria: acid fast stain.

    Science.gov (United States)

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

    2009-11-01

    Acid-fastness is an uncommon characteristic shared by the genera Mycobacterium (Section 10A) and Nocardia. Because of this feature, this stain is extremely helpful in identification of these bacteria. Although Gram positive, acid-fast bacteria do not take the crystal violet into the wall well, appearing very light purple rather than the deep purple of normal Gram-positive bacteria. (c) 2009 by John Wiley & Sons, Inc.

  9. Transformation of gram positive bacteria by sonoporation

    Science.gov (United States)

    Yang, Yunfeng; Li, Yongchao

    2014-03-11

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

  10. Coevolution of antibiotic production and counter-resistance in soil bacteria.

    Science.gov (United States)

    Laskaris, Paris; Tolba, Sahar; Calvo-Bado, Leo; Wellington, Elizabeth M; Wellington, Liz

    2010-03-01

    We present evidence for the coexistence and coevolution of antibiotic resistance and biosynthesis genes in soil bacteria. The distribution of the streptomycin (strA) and viomycin (vph) resistance genes was examined in Streptomyces isolates. strA and vph were found either within a biosynthetic gene cluster or independently. Streptomyces griseus strains possessing the streptomycin cluster formed part of a clonal complex. All S. griseus strains possessing solely strA belonged to two clades; both were closely related to the streptomycin producers. Other more distantly related S. griseus strains did not contain strA. S. griseus strains with only vph also formed two clades, but they were more distantly related to the producers and to one another. The expression of the strA gene was constitutive in a resistance-only strain whereas streptomycin producers showed peak strA expression in late log phase that correlates with the switch on of streptomycin biosynthesis. While there is evidence that antibiotics have diverse roles in nature, our data clearly support the coevolution of resistance in the presence of antibiotic biosynthetic capability within closely related soil dwelling bacteria. This reinforces the view that, for some antibiotics at least, the primary role is one of antibiosis during competition in soil for resources.

  11. Identification of Bacteria and the Effect on Compressive Strength of Concrete

    Directory of Open Access Journals (Sweden)

    Anneza L. H.

    2016-01-01

    Full Text Available This paper presents the species of bacteria used in this study as well as the effect of the bacteria on compressive strength of bioconcrete. Bioconcrete is not only more environmentally friendly but it is easy to procure. The objective of this research is to identify the ureolytic bacteria and sulphate reduction bacteria that have been isolated and further use the bacteria in concrete to determine the effect of bacteria on compressive strength. Identification of bacteria is conducted through Polymerase chain reaction (PCR method and DNA sequencing. The DNA of the bacteria was run through BLAST algorithm to determine the bacterial species.The bacteria were added into the concrete mix as a partial replacement of water. 3% of water is replaced by ureolytic bacteria and 5% of water is replaced by sulphate reduction bacteria. After running BLAST algorithm the bacteria were identified as Enterococcus faecalis (ureolytic bacteria and Bacillus sp (sulphate reduction bacteria. The result of the compressive strength for control is 36.0 Mpa. Partial replacement of 3% water by ureolytic bacteria has strength of 38.2Mpa while partial replacement of 5% of water by sulphate reduction bacteria has strength of 42.5Mpa. The significant increase of compressive strength with the addition of bacteria shows that bacteria play a significant role in the improvement of compressive strength.

  12. Evaluating primers for profiling anaerobic ammonia oxidizing bacteria within freshwater environments.

    Directory of Open Access Journals (Sweden)

    Puntipar Sonthiphand

    Full Text Available Anaerobic ammonia oxidizing (anammox bacteria play an important role in transforming ammonium to nitrogen gas and contribute to fixed nitrogen losses in freshwater environments. Understanding the diversity and abundance of anammox bacteria requires reliable molecular tools, and these are not yet well established for these important Planctomycetes. To help validate PCR primers for the detection of anammox bacteria within freshwater ecosystems, we analyzed representative positive controls and selected samples from Grand River and groundwater sites, both from Ontario, Canada. The objectives of this study were to identify a suitable anammox denaturing gradient gel electrophoresis (DGGE fingerprint method by using GC-clamp modifications to existing primers, and to verify the specificity of anammox-specific primers used for DGGE, cloning and qPCR methods. Six primer combinations were tested from four published primer sets (i.e. A438f/A684r, Amx368f/Amx820r, An7f/An1388r, and Pla46/1392r for both direct and nested PCR amplifications. All PCR products were run subsequently on DGGE gels to compare the resulting patterns. Two anammox-specific primer combinations were also used to generate clone libraries and quantify anammox bacterial 16S rRNA genes with qPCR. The primer set A438f/A684r was highly specific to anammox bacteria, provided reliable DGGE fingerprints and generated a high proportion of anammox-related clones. A second primer set (Amx368f/Amx820r was anammox specific, based on clone library analysis, but PCR products from different candidate species of anammox bacteria resolved poorly using DGGE analysis. Both DGGE and cloning results revealed that Ca. Brocadia and an uncharacterized anammox bacterial cluster represented the majority of anammox bacteria found in Grand River sediment and groundwater samples, respectively. Together, our results demonstrate that although Amx368f/Amx820r was useful for anammox-specific qPCR and clone library

  13. NREL Scientists Model Methane-Eating Bacteria | News | NREL

    Science.gov (United States)

    Scientists Model Methane-Eating Bacteria News Release: NREL Scientists Model Methane-Eating Bacteria February 13, 2018 Nature is full of surprises - not to mention solutions. A research team ) recently explored the possibilities provided by the natural world by researching how the bacteria

  14. Characterization of (per)chlorate-reducing bacteria

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.

    2004-01-01

    Some bacteria can use (per)chlorateas terminal electron acceptor for growth. These bacteria convert perchlorate via chlorate and chlorite into chloride and molecular oxygen. Oxygen formation in microbial respiration is unique. In this study two chlorate-reducing strains

  15. Antibacterial activity of silver-killed bacteria: the "zombies" effect

    Science.gov (United States)

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  16. Gastric spiral bacteria in small felids.

    Science.gov (United States)

    Kinsel, M J; Kovarik, P; Murnane, R D

    1998-06-01

    Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.

  17. Catabolism of lysine by mixed rumen bacteria

    International Nuclear Information System (INIS)

    Onodera, Ryoji; Kandatsu, Makoto.

    1975-01-01

    Metabolites arising from the catabolism of lysine by the mixed rumen bacteria were chromatographically examined by using radioactive lysine. After 6 hr incubation, 241 nmole/ml of lysine was decomposed to give ether-soluble substances and CO 2 by the bacteria and 90 nmole/ml of lysine was incorporated unchanged into the bacteria. delta-Aminovalerate, cadaverine or pipecolate did not seem to be produced from lysine even after incubation of the bacteria with addition of those three amino compounds to trap besides lysine and radioactive lysine. Most of the ether-soluble substances produced from radioactive lysine was volatile fatty acids (VFAs). Fractionation of VFAs revealed that the peaks of butyric and acetic acids coincided with the strong radioactive peaks. Small amounts of radioactivities were detected in propionic acid peak and a peak assumed to be caproic acid. The rumen bacteria appeared to decompose much larger amounts of lysine than the rumen ciliate protozoa did. (auth.)

  18. Biodiversity of Bacteria Isolated from Different Soils

    Directory of Open Access Journals (Sweden)

    Fatma YAMAN

    2017-01-01

    Full Text Available The aim of this study was to determine the biodiversity of PHB producing bacteria isolated from soils where fruit and vegetable are cultivated (onion, grape, olive, mulberry and plum in Aydın providence. Morphological, cultural, biochemical, and molecular methods were used for bacteria identification. These isolated bacteria were identified by 16S rRNA sequencing and using BLAST. The following bacteria Bacillus thuringiensis (6, Bacillus cereus (8, Bacillus anthrachis (1, Bacillus circulans (1, Bacillus weihenstephanensis (1, Pseudomonas putida (1, Azotobacter chroococcum (1, Brevibacterium frigoritolerans (1, Burkholderia sp. (1, Staphylococcus epidermidis (1, Streptomyces exfoliatus (1, Variovorax paradoxus (1 were found. The Maximum Likelihood method was used to produce a molecular phylogenetic analysis and a phylogenetic tree was constructed. These bacteria can produce polyhydroxybutyrate (PHB which is an organic polymer with commercial potential as a biodegradable thermoplastic. PHB can be used instead of petrol derivated non-degradable plastics. For this reason, PHB producing microorganisms are substantial in industry.

  19. Distribution of bacteria and associated minerals in the gill chamber of the vent shrimp Rimicaris exoculata and related biogeochemical processes

    Science.gov (United States)

    Zbinden, M.; Le Bris, N.; Compere, P.; Gaill, F.

    2004-12-01

    The shrimp Rimicaris exoculata dominates the megafauna of some mid-Atlantic Ridge hydrothermal vent fields. This species harbors a rich bacterial epibiosis inside its gill chamber. At the Rainbow vent field, the epibionts are associated with iron oxide deposits. Investigation of both bacteria and minerals by scanning electron microscopy (SEM) and X-ray microanalysis (EDX) shows the occurrence of three distinct compartments in the gill chamber: (1) the lower pre-branchial chamber, housing bacteria, but devoid of minerals, (2) the "true" branchial chamber that contains the gills and remains free of both bacteria and minerals, and (3) the upper pre-branchial chamber housing the main ectosymbiotic bacterial community and associated iron oxides. According to our chemical and temperature data, abiotic iron oxidation appears to be kinetically inhibited in the environment of the shrimps and this would explain the lack of iron oxide deposits in the first two areas. We propose that, in the third area, iron oxidation is microbially promoted. The discrepancy between the spatial distribution of bacteria and minerals suggests that different bacterial metabolisms are involved in the two compartments. A possible explanation lies in the modification of physico-chemical conditions downstream of the gills, that would reduce the oxygen content and favor the development of bacterial iron-oxidizers in this Fe II-rich environment. A potential role of such iron-oxidizing symbionts in the shrimp diet is suggested. This would be unusual for hydrothermal ecosystems, where most previously described symbioses rely on sulphide or methane as an energy source.

  20. The influence of protruding filamentous bacteria on floc stability and solid-liquid separation in the activated sludge process.

    Science.gov (United States)

    Burger, Wilhelm; Krysiak-Baltyn, Konrad; Scales, Peter J; Martin, Gregory J O; Stickland, Anthony D; Gras, Sally L

    2017-10-15

    Filamentous bacteria can impact on the physical properties of flocs in the activated sludge process assisting solid-liquid separation or inducing problems when bacteria are overabundant. While filamentous bacteria within the flocs are understood to increase floc tensile strength, the relationship between protruding external filaments, dewatering characteristics and floc stability is unclear. Here, a quantitative methodology was applied to determine the abundance of filamentous bacteria in activated sludge samples from four wastewater treatment plants. An automated image analysis procedure was applied to identify filaments and flocs and calculate the length of the protruding filamentous bacteria (PFB) relative to the floc size. The correlation between PFB and floc behavior was then assessed. Increased filament abundance was found to increase interphase drag on the settling flocs, as quantified by the hindered settling function. Additionally, increased filament abundance was correlated with a lower gel point concentration leading to poorer sludge compactability. The floc strength factor, defined as the relative change in floc size upon shearing, correlated positively with filament abundance. This influence of external protruding filamentous bacteria on floc stability is consistent with the filamentous backbone theory, where filamentous bacteria within flocs increase floc resistance to shear-induced breakup. A qualitative correlation was also observed between protruding and internal filamentous structure. This study confirms that filamentous bacteria are necessary to enhance floc stability but if excessively abundant will adversely affect solid-liquid separation. The tools developed here will allow quantitative analysis of filament abundance, which is an improvement on current qualitative methods and the improved method could be used to assist and optimize the operation of waste water treatment plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Probiotic bacteria: selective enumeration and survival in dairy foods.

    Science.gov (United States)

    Shah, N P

    2000-04-01

    A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

  2. Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

    Science.gov (United States)

    Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

    2015-02-01

    The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the `greener' technology of second-generation biofuels.

  3. Seed-vectored endophytic bacteria modulate development of rice seedlings.

    Science.gov (United States)

    Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

    2017-06-01

    The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

  4. Comparative quantification of human intestinal bacteria based on cPCR and LDR/LCR.

    Science.gov (United States)

    Tang, Zhou-Rui; Li, Kai; Zhou, Yu-Xun; Xiao, Zhen-Xian; Xiao, Jun-Hua; Huang, Rui; Gu, Guo-Hao

    2012-01-21

    To establish a multiple detection method based on comparative polymerase chain reaction (cPCR) and ligase detection reaction (LDR)/ligase chain reaction (LCR) to quantify the intestinal bacterial components. Comparative quantification of 16S rDNAs from different intestinal bacterial components was used to quantify multiple intestinal bacteria. The 16S rDNAs of different bacteria were amplified simultaneously by cPCR. The LDR/LCR was examined to actualize the genotyping and quantification. Two beneficial (Bifidobacterium, Lactobacillus) and three conditionally pathogenic bacteria (Enterococcus, Enterobacterium and Eubacterium) were used in this detection. With cloned standard bacterial 16S rDNAs, standard curves were prepared to validate the quantitative relations between the ratio of original concentrations of two templates and the ratio of the fluorescence signals of their final ligation products. The internal controls were added to monitor the whole detection flow. The quantity ratio between two bacteria was tested. cPCR and LDR revealed obvious linear correlations with standard DNAs, but cPCR and LCR did not. In the sample test, the distributions of the quantity ratio between each two bacterial species were obtained. There were significant differences among these distributions in the total samples. But these distributions of quantity ratio of each two bacteria remained stable among groups divided by age or sex. The detection method in this study can be used to conduct multiple intestinal bacteria genotyping and quantification, and to monitor the human intestinal health status as well.

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

    Science.gov (United States)

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

    2015-12-01

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

  6. Beneficial effects of antioxidative lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hisako Nakagawa

    2017-01-01

    Full Text Available Oxidative stress is caused by exposure to reactive oxygen intermediates. The oxidative damage of cell components such as proteins, lipids, and nucleic acids one of the important factors associated with diabetes mellitus, cancers and cardiovascular diseases. This occurs as a result of imbalance between the generations of oxygen derived radicals and the organism’s antioxidant potential. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. To date, many studies have focused on food sources, nutrients, and components that exert antioxidant activity in worms, flies, mice, and humans. Probiotics, live microorganisms that when administered in adequate amounts provide many beneficial effects on the human health, have been attracting growing interest for their health-promoting effects, and have often been administered in fermented milk products. In particular, lactic acid bacteria (LAB are known to conferre physiologic benefits. Many studies have indicated the antioxidative activity of LAB. Here we review that the effects of lactic acid bacteria to respond to oxidative stress, is connected to oxidative-stress related disease and aging.

  7. Assessment on Bacteria in the Heavy Metal Bioremediation

    International Nuclear Information System (INIS)

    Mohamad Romizan Osman; Mohamad Romizan Osman; Azman Azid; Kamaruzzaman Yunus; Ahmad Dasuki Mustafa; Mohammad Azizi Amran; Fazureen Azaman; Zarizal Suhaili; Yahya Abu Bakar; Syahrir Farihan Mohamed Zainuddin

    2015-01-01

    The aim of this study was to identify and verify the potential bacteria as the bioremediation agent. It involved bacteria isolation, identification through Gram staining, analytical profile index (API) test and determine bioremediation activities by using inductively coupled plasma mass spectrometry (ICPMS). The soil and water sample were collected from downstream of Galing River, Kuantan Malaysia. Based on phenotypic identification and biochemical analysis, the bacteria present at the vicinity area are possibility of Myroides spp. and Micrococcus spp. These bacteria were proven as bioremediation agent based on the ICPMS result. The result 1 ppm of Zink (Zn), Lead (Pb), Arsenic (As), Selenium (Se), Cadmium (Cd), Manganese (Mn), and Indium (In) dwindled after the bacteria inoculated and incubated for seven days in mixture of base salt media (BSM) with the heavy metal elements. Therefore, this proves that the bacteria which are present at downstream of Galing River, Kuantan Malaysia are significant to help us in the bioremediation activity to decrease the heavy metal pollution in the environment. (author)

  8. Bacteria-based concrete: from concept to market

    Science.gov (United States)

    Wiktor, V.; Jonkers, H. M.

    2016-08-01

    The concept of self-healing concrete—a concrete which can autonomously repair itself after crack formation, with no or limited human intervention—has received a lot of attention over the past 10 years as it could help structures to last longer and at a lower maintenance cost. This paper gives an overview on the key aspects and recent advances in the development of the bacteria-based self-healing concrete developed at the University of Technology of Delft (The Netherlands). Research started with the screening and selection of concrete compatible bacteria and nutrients. Several types of encapsulated bacteria and nutrients have been developed and tested. The functionality of these healing agents was demonstrated by showing metabolic activity of activated bacterial spores by oxygen consumption measurements and by regain of material functionality in form of regain of water tightness. Besides development of bacteria-based self-healing concrete, a bacteria-based repair mortar and liquid system were developed for the treatment of aged concrete structures. Field trials have been carried out with either type of bacteria-based systems and the promising results have led to a spinoff company Basilisk Self-Healing Concrete with the aim to further develop these systems and bring them to the market.

  9. Rapid diagnostics of the bacteria in air

    Energy Technology Data Exchange (ETDEWEB)

    Belov Nikolai, N. [ATECH KFT, Budapest (Hungary)

    2000-07-01

    Presence of the bacteria and viruses in the air is great problem now. Terrorists are going to use the bacteria weapon. Now biotechnology provides very cheap equipment ({approx} $500) for modification of the bacteria sorts. It may be used for receiving of new variants of the bacteriological weapon. And presence of one small bacteria aerosol generator in the international airport during several days will start the dangerous epidemic incidence the entire world. From another side - poor countries with hot and wet weather are continuously producing new and new dangerous bacteria. Every year epidemic waves of influence are going from China, India or Africa. And once up a time it will be epidemic explosive with fast lethal finish. Methods of estimation of the bio-aerosols in Air of City are very poor. Standard Bio-aerosol sampler has two conflicting demands. From one side the bio-sampler needs in great air volume of sample with great efficiency of separation of aerosol particles from measured air. From another side all selected particles needs in great care. This demand carried out from method of measurement of bacteria in sample by counting of colonies that grew from bacteria on nutrient media after incubation time. It is a problem to prevent bacterial flora from death during collecting aerosol sample. This time of growth and counting of colony is so long that result of this measurement will be unusable if it will be terrorist action of start of bacteriological was. Here presented new methods for fast diagnostics of the bacteria in the air. It consists from 4 general parts: (1) Micro-droplet method for diagnostics of biological active substances in aerosol sample. This method allows to control the bio-particle position on the plate, to use series of biochemistry species for analytical reaction for this small bio-particle. Small volume of biochemical reaction reduces noise. This method provides extremely high sensitivity for discovering of biological material. (2

  10. Anti-bacteria effect of active ingredients of siraitia grosvenorii on the spoilage bacteria isolated from sauced pork head meat

    Science.gov (United States)

    Li, X.; Xu, L. Y.; Cui, Y. Q.; Pang, M. X.; Wang, F.; Qi, J. H.

    2018-01-01

    Extraction and anti-bacteria effect of active ingredients of Siraitia grosvenorii were studied in this paper. Extraction combined with ultrasonic was adopted. The optimum extraction condition was determined by single factor test; the anti-bacteria effect of active ingredients and minimum inhibitory concentration (MIC) were valued by Oxford-cup method. The results indicated that optimum extraction condition of active ingredients extracted from Siraitia grosvenorii were described as follows: ethanol concentrations of sixty-five percent and twenty minutes with ultrasonic assisted extraction; the active ingredients of Siraitia grosvenorii had anti-bacteria effect on Staphylococcus epidermidis, Proteus vulgaris, Bacillus sp, Serratia sp and MIC was 0.125g/mL, 0.0625g/mL, 0.125g/mL and 0.125g/mL. The active constituent of Siraitia grosvenorii has obvious anti-bacteria effect on the spoilage bacteria isolated from Sauced pork head meat and can be used as a new natural food preservation to prolong the shelf-life of Low-temperature meat products.

  11. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  12. Relationship between halitosis and periodontal disease - associated oral bacteria in tongue coatings.

    Science.gov (United States)

    Amou, T; Hinode, D; Yoshioka, M; Grenier, D

    2014-05-01

    The objective of our study was to investigate the relationship between halitosis and oral bacteria in tongue coating (TC) and saliva samples from patients with halitosis, and to evaluate the effect of tongue cleaning on halitosis. Ninety-four participants complaining of oral malodour were included in the study. Organoleptic (OR) values, volatile sulphur compound (VSC) concentrations determined by gas chromatography and TC scores were used as clinical parameters of halitosis. Quantitative real-time polymerase chain reactions were used to determine the numbers of periodontal disease-associated oral bacteria. There was a significant correlation between TC scores and OR values, methylmercaptan (CH3 SH) concentrations and VSC concentrations (Spearman's rank-correlation coefficient test, P periodontal disease-associated oral bacteria in TCs are closely related to halitosis and that tongue cleaning may be an effective method for improving halitosis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Isolation and characterization of feather degrading bacteria from ...

    African Journals Online (AJOL)

    This study is aimed at isolating and characterizing new culturable feather degrading bacteria from soils of the University of Mauritius Farm. Bacteria that were isolated were tested for their capability to grow on feather meal agar (FMA). Proteolytic bacteria were tested for feather degradation and were further identified ...

  14. Bacteria associated with cultures of psathyrella atroumbonata (Pleger)

    African Journals Online (AJOL)

    These bacteria include Bacillus licheniformis, Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The average bacteria count was 1.0 x 106 cfu/ml and these bacteria grew within pH range of 5.0 and 9.0. the optimum temperature range of growth lied ...

  15. In vivo IgA coating of anaerobic bacteria in human faeces

    NARCIS (Netherlands)

    vanderWaaij, LA; Limburg, PC; Mesander, G; vanderWaaij, D

    The bacterial flora in the human colon, although extremely diverse, has a relatively stable composition and non-infectious anaerobic bacteria are dominant. The flora forms a pool of numerous different antigens separated from mucosal immunocompetent cells by just a single layer of epithelial cells.

  16. Gram-negative bacteria account for main differences between faecal microbiota from patients with ulcerative colitis and healthy controls

    DEFF Research Database (Denmark)

    Vigsnæs, Louise Kristine; Brynskov, J.; Steenholdt, C.

    2012-01-01

    process of the gut mucosa. The aim of this study was to investigate the faecal microbiota in patients either with UC in remission (n=6) or with active disease (n=6), and in healthy controls (n=6). The composition of Gram-negative bacteria and Gram-positive bacteria was examined. Antigenic structures...... of Gram-negative bacteria such as lipopolysaccharides have been related to the inflammatory responses and pathogenesis of inflammatory bowel disease. Dice cluster analysis and principal component analysis of faecal microbiota profiles obtained by denaturing gradient gel electrophoresis and quantitative...... PCR, respectively, revealed that the composition of faecal bacteria from UC patients with active disease differed from the healthy controls and that this difference should be ascribed to Gram-negative bacteria. The analysis did not show any clear grouping of UC patients in remission. Even...

  17. Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Beata Nalepa

    2012-01-01

    Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

  18. Identification and antimicrobial susceptibility of obligate anaerobic bacteria from clinical samples of animal origin.

    Science.gov (United States)

    Mayorga, Melissa; Rodríguez-Cavallini, Evelyn; López-Ureña, Diana; Barquero-Calvo, Elías; Quesada-Gómez, Carlos

    2015-12-01

    The etiology of veterinary infectious diseases has been the focus of considerable research, yet relatively little is known about the causative agents of anaerobic infections. Susceptibility studies have documented the emergence of antimicrobial resistance and indicate distinct differences in resistance patterns related to veterinary hospitals, geographic regions, and antibiotic-prescribing regimens. The aim of the present study was to identify the obligate anaerobic bacteria from veterinary clinical samples and to determinate the in vitro susceptibility to eight antimicrobials and their resistance-associated genes. 81 clinical specimens obtained from food-producing animals, pets and wild animals were examined to determine the relative prevalence of obligate anaerobic bacteria, and the species represented. Bacteroides spp, Prevotella spp and Clostridium spp represented approximately 80% of all anaerobic isolates. Resistance to metronidazole, clindamycin, tetracycline and fluoroquinolones was found in strains isolated from food-producing animals. Ciprofloxacin, enrofloxacin and cephalotin showed the highest resistance in all isolates. In 17%, 4% and 14% of tetracycline-resistant isolates, the resistance genes tetL, tetM and tetW were respectively amplified by PCR whereas in 4% of clindamycin-resistant strains the ermG gene was detected. 26% of the isolates were positive for cepA, while only 6% harbored the cfxA (resistance-conferring genes to beta-lactams). In this study, the obligate anaerobic bacteria from Costa Rica showed a high degree of resistance to most antimicrobials tested. Nevertheless, in the majority of cases this resistance was not related to the resistance acquired genes usually described in anaerobes. It is important to address and regulate the use of antimicrobials in the agricultural industry and the empirical therapy in anaerobic bacterial infections in veterinary medicine, especially since antibiotics and resistant bacteria can persist in the

  19. Evaluation of the probiotic potential of lactic acid bacteria isolated ...

    African Journals Online (AJOL)

    The probiotic-related characteristics of 55 strains of lactic acid bacteria isolated from the faeces of 3 - 6 months old breast-fed infants were determined. The API 50 CH and SDS-PAGE techniques were employed to ascertain the identity of the isolated strains. The predominant species among the isolated strains were ...

  20. Diversity and distribution of planktonic anaerobic ammonium-oxidizing bacteria in the Dongjiang River, China.

    Science.gov (United States)

    Sun, Wei; Xia, Chunyu; Xu, Meiying; Guo, Jun; Wang, Aijie; Sun, Guoping

    2014-12-01

    Anaerobic ammonium-oxidizing (anammox) process has recently been recognized as an important pathway for removing fixed nitrogen (N) from aquatic ecosystems. Anammox organisms are widely distributed in freshwater environments. However, little is known about their presence in the water column of riverine ecosystems. Here, the existence of a diverse anammox community was revealed in the water column of the Dongjiang River by analyzing 16S rRNA and hydrazine oxidation (hzo) genes of anammox bacteria. Phylogenetic analyses of hzo genes showed that Candidatus Jettenia related clades of anammox bacteria were dominant in the river, suggesting the ecological microniche distinction from freshwater/estuary and marine anammox bacteria with Ca. Brocadia and Kuenenia genera mainly detected in freshwater/estuary ecosystems, and Ca. Scalindua genus mainly detected in marine ecosystems. The abundance and diversity of anammox bacteria along the river were both significantly correlated with concentrations of NH4(+)-N based on Pearson and partial correlation analyses. Redundancy analyses showed the contents of NH4(+)-N, NO3(-)-N and the ratio of NH4(+)-N to NO2(-)-N significantly influenced the spatial distributions of anammox bacteria in the water column of the Dongjiang River. These results expanded our understanding of the distribution and potential roles of anammox bacteria in the water column of the river ecosystem. Copyright © 2014 Elsevier GmbH. All rights reserved.

  1. Molecular detection of anaerobic ammonium-oxidizing (anammox) bacteria in high-temperature petroleum reservoirs.

    Science.gov (United States)

    Li, Hui; Chen, Shuo; Mu, Bo-Zhong; Gu, Ji-Dong

    2010-11-01

    Anaerobic ammonium-oxidizing (anammox) process plays an important role in the nitrogen cycle of the worldwide anoxic and mesophilic habitats. Recently, the existence and activity of anammox bacteria have been detected in some thermophilic environments, but their existence in the geothermal subterranean oil reservoirs is still not reported. This study investigated the abundance, distribution and functional diversity of anammox bacteria in nine out of 17 high-temperature oil reservoirs by molecular ecology analysis. High concentration (5.31-39.2 mg l(-1)) of ammonium was detected in the production water from these oilfields with temperatures between 55°C and 75°C. Both 16S rRNA and hzo molecular biomarkers indicated the occurrence of anammox bacteria in nine out of 17 samples. Most of 16S rRNA gene phylotypes are closely related to the known anammox bacterial genera Candidatus Brocadia, Candidatus Kuenenia, Candidatus Scalindua, and Candidatus Jettenia, while hzo gene phylotypes are closely related to the genera Candidatus Anammoxoglobus, Candidatus Kuenenia, Candidatus Scalindua, and Candidatus Jettenia. The total bacterial and anammox bacterial densities were 6.4 ± 0.5 × 10(3) to 2.0 ± 0.18 × 10(6) cells ml(-1) and 6.6 ± 0.51 × 10(2) to 4.9 ± 0.36 × 10(4) cell ml(-1), respectively. The cluster I of 16S rRNA gene sequences showed distant identity (<92%) to the known Candidatus Scalindua species, inferring this cluster of anammox bacteria to be a new species, and a tentative name Candidatus "Scalindua sinooilfield" was proposed. The results extended the existence of anammox bacteria to the high-temperature oil reservoirs.

  2. Rock-degrading endophytic bacteria in cacti

    Science.gov (United States)

    M. Esther Puente; Ching Y. Li; Yoav Bashan

    2009-01-01

    A plant-bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2. produce...

  3. Rapid separation of bacteria from blood - Chemical aspects.

    Science.gov (United States)

    Alizadeh, Mahsa; Wood, Ryan L; Buchanan, Clara M; Bledsoe, Colin G; Wood, Madison E; McClellan, Daniel S; Blanco, Rae; Ravsten, Tanner V; Husseini, Ghaleb A; Hickey, Caroline L; Robison, Richard A; Pitt, William G

    2017-06-01

    To rapidly diagnose infectious organisms causing blood sepsis, bacteria must be rapidly separated from blood, a very difficult process considering that concentrations of bacteria are many orders of magnitude lower than concentrations of blood cells. We have successfully separated bacteria from red and white blood cells using a sedimentation process in which the separation is driven by differences in density and size. Seven mL of whole human blood spiked with bacteria is placed in a 12-cm hollow disk and spun at 3000rpm for 1min. The red and white cells sediment more than 30-fold faster than bacteria, leaving much of the bacteria in the plasma. When the disk is slowly decelerated, the plasma flows to a collection site and the red and white cells are trapped in the disk. Analysis of the recovered plasma shows that about 36% of the bacteria is recovered in the plasma. The plasma is not perfectly clear of red blood cells, but about 94% have been removed. This paper describes the effects of various chemical aspects of this process, including the influence of anticoagulant chemistry on the separation efficiency and the use of wetting agents and platelet aggregators that may influence the bacterial recovery. In a clinical scenario, the recovered bacteria can be subsequently analyzed to determine their species and resistance to various antibiotics. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Interannual variability and sensitivity analysis of manure-borne bacteria transport from irrigated fields.

    Science.gov (United States)

    Martinez, Gonzalo; Pachepsky, Yakov; Shelton, Daniel; Guber, Andrey; Yakirevich, Alexander; Dughtry, Craig; Goodrich, David

    2014-05-01

    Manure application has been implicated in deterioration of microbial quality of surface water utilized in recreation, irrigation, aquaculture, and various household- and agriculture-related processes. The model KINEROS2/STWIR has been recently developed for rainfall- or irrigation event-based simulations of manure-borne overland bacteria transport. Information on uncertainty in the model parameter values is essential for running sensitivity analysis, creating synthetic datasets, developing risk assessment projects, etc. The objective of this work was to analyze data obtained in multiple years when the status of soil surface, soil structure, and weed cover created palpably different conditions for overland microorganism transport. Experiments were carried out at the Beltsville USDA OPE3 site, which is a part of the Lower Chesapeake Long-term Agricultural Research Network Site. Manure was applied at typical Maryland rates and the two-hour irrigation was applied immediately after manure application and one week later. Escherichia coli and thermotolerant coliform concentrations in runoff and the bacteria contents in manure and soil before and after application were measured across the application area of about 100 m x 50 m on the 40-point grid. Bacteria contents in manure varied up to six orders of magnitude. No spatial structure in these contents was found at the support and spacing of this work. Parameters sets were substantially different for thermotolerant coliforms and E. coli. Bacteria adsorption and straining parameters varied by one order of magnitude over three year trials. Variability of Manning roughness coefficient, saturated hydraulic conductivity, net capillary drive, relative saturation, and solute dispersivity was substantially smaller. The hypothesis of applicability of uniform distributions to simulate the empirical distributions of above parameters could not be rejected at the 0.05 significance level. The Bradford-Schijven model was used to simulate

  5. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Antibiotic-Resistant Enteric Bacteria in Environmental Waters

    Directory of Open Access Journals (Sweden)

    Lisa M. Casanova

    2016-11-01

    Full Text Available Sources of antibiotic resistant organisms, including concentrated animal feeding operations (CAFOs, may lead to environmental surface and groundwater contamination with resistant enteric bacteria of public health concern. The objective of this research is to determine whether Salmonella, Escherichia coli, Yersinia enterocolitica, and enterococci resistant to clinically relevant antibiotics are present in surface and groundwater sources in two eastern North Carolina counties, Craven and Wayne. 100 surface and groundwater sites were sampled for Salmonella, E. coli, and enterococci, and the bacteria isolated from these samples were tested for susceptibility to clinically relevant antibiotics. Salmonella were detected at low levels in some surface but not groundwater. E. coli were in surface waters but not ground in both counties. Enterococci were present in surface water and a small number of groundwater sites. Yersinia was not found. Bacterial densities were similar in both counties. For Salmonella in surface water, the most frequent type of resistance was to sulfamethoxazole. There was no ciprofloxacin resistance. There were a few surface water E. coli isolates resistant to chloramphenicol, gentamicin, and ampicillin. Enterococci in surface water had very low levels of resistance to vancomycin, chloramphenicol, ampicillin, and streptomycin. E. coli and enterococci are present more frequently and at higher levels in surface water than Salmonella, but groundwater contamination with any of these organisms was rare, and low levels of resistance can be found sporadically. Resistant bacteria are relatively uncommon in these eastern N.C. surface and groundwaters, but they could pose a risk of human exposure via ingestion or primary contact recreation.

  7. Comparative genomics of the lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  8. Unsaturated Fatty Acid, cis-2-Decenoic Acid, in Combination with Disinfectants or Antibiotics Removes Pre-Established Biofilms Formed by Food-Related Bacteria

    Science.gov (United States)

    Sepehr, Shayesteh; Rahmani-Badi, Azadeh; Babaie-Naiej, Hamta; Soudi, Mohammad Reza

    2014-01-01

    Biofilm formation by food-related bacteria and food-related pathogenesis are significant problems in the food industry. Even though much disinfection and mechanical procedure exist for removal of biofilms, they may fail to eliminate pre-established biofilms. cis-2 decenoic acid (CDA), an unsaturated fatty acid messenger produced by Pseudomonas aeruginosa, is reportedly capable of inducing the dispersion of established biofilms by multiple types of microorganisms. However, whether CDA has potential to boost the actions of certain antimicrobials is unknown. Here, the activity of CDA as an inducer of pre-established biofilms dispersal, formed by four main food pathogens; Staphylococcus aureus, Bacillus cereus, Salmonella enterica and E. coli, was measured using both semi-batch and continuous cultures bioassays. To assess the ability of CDA combined biocides treatments to remove pre-established biofilms formed on stainless steel discs, CFU counts were performed for both treated and untreated cultures. Eradication of the biofilms by CDA combined antibiotics was evaluated using crystal violet staining. The effect of CDA combined treatments (antibiotics and disinfectants) on biofilm surface area and bacteria viability was evaluated using fluorescence microscopy, digital image analysis and LIVE/DEAD staining. MICs were also determined to assess the probable inhibitory effects of CDA combined treatments on the growth of tested microorganisms' planktonic cells. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least two-fold increase in the number of planktonic cells in all cultures. While antibiotics or disinfectants alone exerted a trivial effect on CFU counts and percentage of surface area covered by the biofilms, combinational treatments with both 310 nM CDA and antibiotics or disinfectants led to approximate 80% reduction in biofilm biomass. These data suggests that combined treatments with CDA would pave the way toward developing new strategies

  9. Unsaturated fatty acid, cis-2-decenoic acid, in combination with disinfectants or antibiotics removes pre-established biofilms formed by food-related bacteria.

    Directory of Open Access Journals (Sweden)

    Shayesteh Sepehr

    Full Text Available Biofilm formation by food-related bacteria and food-related pathogenesis are significant problems in the food industry. Even though much disinfection and mechanical procedure exist for removal of biofilms, they may fail to eliminate pre-established biofilms. cis-2 decenoic acid (CDA, an unsaturated fatty acid messenger produced by Pseudomonas aeruginosa, is reportedly capable of inducing the dispersion of established biofilms by multiple types of microorganisms. However, whether CDA has potential to boost the actions of certain antimicrobials is unknown. Here, the activity of CDA as an inducer of pre-established biofilms dispersal, formed by four main food pathogens; Staphylococcus aureus, Bacillus cereus, Salmonella enterica and E. coli, was measured using both semi-batch and continuous cultures bioassays. To assess the ability of CDA combined biocides treatments to remove pre-established biofilms formed on stainless steel discs, CFU counts were performed for both treated and untreated cultures. Eradication of the biofilms by CDA combined antibiotics was evaluated using crystal violet staining. The effect of CDA combined treatments (antibiotics and disinfectants on biofilm surface area and bacteria viability was evaluated using fluorescence microscopy, digital image analysis and LIVE/DEAD staining. MICs were also determined to assess the probable inhibitory effects of CDA combined treatments on the growth of tested microorganisms' planktonic cells. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least two-fold increase in the number of planktonic cells in all cultures. While antibiotics or disinfectants alone exerted a trivial effect on CFU counts and percentage of surface area covered by the biofilms, combinational treatments with both 310 nM CDA and antibiotics or disinfectants led to approximate 80% reduction in biofilm biomass. These data suggests that combined treatments with CDA would pave the way toward

  10. Sulfate reducing bacteria detection in gas pipelines; Deteccao de bacterias redutoras de sulfato em gasodutos

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbach, Marcia Teresa S.; Oliveira, Ana Lucia C. de; Cavalcanti, Eduardo H. de S. [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil). Div. de Corrosao e Degradacao]. E-mails: marciasl@int.gov.br; analucia@int.gov.br; eduardoh@int.gov.br

    2004-07-01

    Microbiology induced corrosion (MIC) process associated with sulfate reducing bacteria (BRS) are one of the most important matter of concern for the oil and gas industry as 77% of failures have been attributed this sort of degradation. Corrosion products found present in gas transportation pipelines, the so-called 'black-powder' problem, are also a nuisance and source of economic losses for the gas industry. According to the literature, the incidence of black-powder can be ascribed to the metabolism of BRS that can be found in the gas environment. Integrity monitoring programs of gas pipelines adopt pigging as an important tool for internal corrosion monitoring. Solid residue such as the black-powder, collected by pigging, as well as the condensed, can be seen as a very valuable samples for microbiological analyses that can be used to detect and quantify bacteria related to the incidence of MIC processes. In the present work results concerning samples collected by pigging and condensed are presented. Small populations of viable BRS have been found in the pipeline. It can be seen that the inclusion of microbiological analyses of solid and liquid residues as a complementary action in the integrity monitoring programs adopted by gas transportation industry can be very helpful on the decision making concerning preventive and corrective actions to be taken in order to maintain the CIM processes under control. (author)

  11. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon...... and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  12. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina; Moura, Jose J.G.

    2008-01-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m -2 that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces

  13. Mortality of fecal bacteria in seawater

    International Nuclear Information System (INIS)

    Garcia-Lara, J.; Menon, P.; Servais, P.; Billen, G.

    1991-01-01

    The authors propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloracetic acid-insoluble fraction in water samples to which [ 3 H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, they found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate

  14. Beer spoilage bacteria and hop resistance.

    Science.gov (United States)

    Sakamoto, Kanta; Konings, Wil N

    2003-12-31

    For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-alpha-acids in beer, have antibacterial activity against Gram-positive bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H(+)-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer spoilage strains from nonspoilers. The horA-PCR method has been applied for bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However

  15. Anaerobic bacteria that dechlorinate perchloroethene.

    Science.gov (United States)

    Fathepure, B Z; Nengu, J P; Boyd, S A

    1987-01-01

    In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

  16. Modulation of immune homeostasis by commensal bacteria

    Science.gov (United States)

    Ivanov, Ivaylo I.; Littman, Dan R.

    2011-01-01

    Intestinal bacteria form a resident community that has co-evolved with the mammalian host. In addition to playing important roles in digestion and harvesting energy, commensal bacteria are crucial for the proper functioning of mucosal immune defenses. Most of these functions have been attributed to the presence of large numbers of “innocuous” resident bacteria that dilute or occupy niches for intestinal pathogens or induce innate immune responses that sequester bacteria in the lumen, thus quenching excessive activation of the mucosal immune system. However it has recently become obvious that commensal bacteria are not simply beneficial bystanders, but are important modulators of intestinal immune homeostasis and that the composition of the microbiota is a major factor in pre-determining the type and robustness of mucosal immune responses. Here we review specific examples of individual members of the microbiota that modify innate and adaptive immune responses, and we focus on potential mechanisms by which such species-specific signals are generated and transmitted to the host immune system. PMID:21215684

  17. Metabolic engineering of lactic acid bacteria for the production of nutraceuticals

    NARCIS (Netherlands)

    Hugenholtz, J.; Sybesma, W.; Groot, M.N.; Wisselink, W.; Ladero, V.; Burgess, K.; Sinderen, van D.; Piard, J.C.; Eggink, G.; Smid, E.J.; Savoy, G.; Sesma, F.; Jansen, T.; Hols, P.; Kleerebezem, M.

    2002-01-01

    Lactic acid bacteria display a relatively simple and well-described metabolism where the sugar source is converted mainly to lactic acid. Here we will shortly describe metabolic engineering strategies on the level of sugar metabolism, that lead to either the efficient re-routing of the lactococcal

  18. Uptake of americium-241 by algae and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Geisy, J P; Paine, D

    1978-01-01

    Algae and bacteria are important factors in the transport and mobilization of elements in the biosphere. These factors may be involved in trophic biomagnification, resulting in a potential human hazard or environmental degradation. Although americium, one of the most toxic elements known, is not required for plant growth, it may be concentrated by algae and bacteria. Therefore, the availability of americium-241 to algae and bacteria was studied to determine their role in the ultimate fate of this element released into the environment. Both algae and bacteria concentrated americium-241 to a high degree, making them important parts of the biomagnification process. The ability to concentrate americium-241 makes algae and bacteria potentially significant factors in cycling this element in the water column. (4 graphs, numerous references, 3 tables)

  19. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....

  20. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  1. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  2. Visualizing aquatic bacteria by light and transmission electron microscopy.

    Science.gov (United States)

    Silva, Thiago P; Noyma, Natália P; Duque, Thabata L A; Gamalier, Juliana P; Vidal, Luciana O; Lobão, Lúcia M; Chiarini-Garcia, Hélio; Roland, Fábio; Melo, Rossana C N

    2014-01-01

    The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.

  3. Isolation of butanol- and isobutanol-tolerant bacteria and physiological characterization of their butanol tolerance.

    Science.gov (United States)

    Kanno, Manabu; Katayama, Taiki; Tamaki, Hideyuki; Mitani, Yasuo; Meng, Xian-Ying; Hori, Tomoyuki; Narihiro, Takashi; Morita, Naoki; Hoshino, Tamotsu; Yumoto, Isao; Kimura, Nobutada; Hanada, Satoshi; Kamagata, Yoichi

    2013-11-01

    Despite their importance as a biofuel production platform, only a very limited number of butanol-tolerant bacteria have been identified thus far. Here, we extensively explored butanol- and isobutanol-tolerant bacteria from various environmental samples. A total of 16 aerobic and anaerobic bacteria that could tolerate greater than 2.0% (vol/vol) butanol and isobutanol were isolated. A 16S rRNA gene sequencing analysis revealed that the isolates were phylogenetically distributed over at least nine genera: Bacillus, Lysinibacillus, Rummeliibacillus, Brevibacillus, Coprothermobacter, Caloribacterium, Enterococcus, Hydrogenoanaerobacterium, and Cellulosimicrobium, within the phyla Firmicutes and Actinobacteria. Ten of the isolates were phylogenetically distinct from previously identified butanol-tolerant bacteria. Two relatively highly butanol-tolerant strains CM4A (aerobe) and GK12 (obligate anaerobe) were characterized further. Both strains changed their membrane fatty acid composition in response to butanol exposure, i.e., CM4A and GK12 exhibited increased saturated and cyclopropane fatty acids (CFAs) and long-chain fatty acids, respectively, which may serve to maintain membrane fluidity. The gene (cfa) encoding CFA synthase was cloned from strain CM4A and expressed in Escherichia coli. The recombinant E. coli showed relatively higher butanol and isobutanol tolerance than E. coli without the cfa gene, suggesting that cfa can confer solvent tolerance. The exposure of strain GK12 to butanol by consecutive passages even enhanced the growth rate, indicating that yet-unknown mechanisms may also contribute to solvent tolerance. Taken together, the results demonstrate that a wide variety of butanol- and isobutanol-tolerant bacteria that can grow in 2.0% butanol exist in the environment and have various strategies to maintain structural integrity against detrimental solvents.

  4. Microfluidic Transducer for Detecting Nanomechanical Movements of Bacteria

    Science.gov (United States)

    Kara, Vural; Ekinci, Kamil

    2017-11-01

    Various nanomechanical movements of bacteria are currently being explored as an indication of bacterial viability. Most notably, these movements have been observed to subside rapidly and dramatically when the bacteria are exposed to an effective antibiotic. This suggests that monitoring bacterial movements, if performed with high fidelity, can offer a path to various clinical microbiological applications, including antibiotic susceptibility tests. Here, we introduce a robust and sensitive microfluidic transduction technique for detecting the nanomechanical movements of bacteria. The technique is based on measuring the electrical fluctuations in a microchannel which the bacteria populate. These electrical fluctuations are caused by the swimming of motile, planktonic bacteria and random oscillations of surface-immobilized bacteria. The technique provides enough sensitivity to detect even the slightest movements of a single cell and lends itself to smooth integration with other microfluidic methods and devices; it may eventually be used for rapid antibiotic susceptibility testing. We acknowledge support from Boston University Office of Technology Development, Boston University College of Engineering, NIH (1R03AI126168-01) and The Wallace H. Coulter Foundation.

  5. Porphyromonas gingivalis and related bacteria: from colonial pigmentation to the type IX secretion system and gliding motility

    Science.gov (United States)

    Nakayama, K

    2015-01-01

    Porphyromonas gingivalis is a gram-negative, non-motile, anaerobic bacterium implicated as a major pathogen in periodontal disease. P. gingivalis grows as black-pigmented colonies on blood agar, and many bacteriologists have shown interest in this property. Studies of colonial pigmentation have revealed a number of important findings, including an association with the highly active extracellular and surface proteinases called gingipains that are found in P. gingivalis. The Por secretion system, a novel type IX secretion system (T9SS), has been implicated in gingipain secretion in studies using non-pigmented mutants. In addition, many potent virulence proteins, including the metallocarboxypeptidase CPG70, 35 kDa hemin-binding protein HBP35, peptidylarginine deiminase PAD and Lys-specific serine endopeptidase PepK, are secreted through the T9SS. These findings have not been limited to P. gingivalis but have been extended to other bacteria belonging to the phylum Bacteroidetes. Many Bacteroidetes species possess the T9SS, which is associated with gliding motility for some of these bacteria. PMID:25546073

  6. Molecular Diversity, Cultivation, and Improved Detection by Fluorescent In Situ Hybridization of a Dominant Group of Human Gut Bacteria Related to Roseburia spp. or Eubacterium rectale

    OpenAIRE

    Aminov, Rustam I.; Walker, Alan W.; Duncan, Sylvia H.; Harmsen, Hermie J. M.; Welling, Gjalt W.; Flint, Harry J.

    2006-01-01

    Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 i...

  7. Abundance and Diversity of Denitrifying and Anammox Bacteria in Seasonally Hypoxic and Sulfidic Sediments of the Saline Lake Grevelingen

    Science.gov (United States)

    Lipsewers, Yvonne A.; Hopmans, Ellen C.; Meysman, Filip J. R.; Sinninghe Damsté, Jaap S.; Villanueva, Laura

    2016-01-01

    Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox, and sulfide-dependent denitrifying bacteria in the sediments of the seasonally hypoxic saline Lake Grevelingen, known to harbor an active microbial community involved in sulfur oxidation pathways. Depth distributions of 16S rRNA gene, nirS gene of denitrifying and anammox bacteria, aprA gene of sulfur-oxidizing and sulfate-reducing bacteria, and ladderane lipids of anammox bacteria were studied in sediments impacted by seasonally hypoxic bottom waters. Samples were collected down to 5 cm depth (1 cm resolution) at three different locations before (March) and during summer hypoxia (August). The abundance of denitrifying bacteria did not vary despite of differences in oxygen and sulfide availability in the sediments, whereas anammox bacteria were more abundant in the summer hypoxia but in those sediments with lower sulfide concentrations. The potential activity of denitrifying and anammox bacteria as well as of sulfur-oxidizing, including sulfide-dependent denitrifiers and sulfate-reducing bacteria, was potentially inhibited by the competition for nitrate and nitrite with cable and/or Beggiatoa-like bacteria in March and by the accumulation of sulfide in the summer hypoxia. The simultaneous presence and activity of organoheterotrophic denitrifying bacteria, sulfide-dependent denitrifiers, and anammox bacteria suggests a tight network of bacteria coupling carbon-, nitrogen-, and sulfur cycling in Lake Grevelingen sediments. PMID:27812355

  8. Abundance and diversity of denitrifying and anammox bacteria in seasonally hypoxic and sulfidic sediments of the saline Lake Grevelingen

    Directory of Open Access Journals (Sweden)

    Yvonne A. Lipsewers

    2016-10-01

    Full Text Available Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity and potential activity of denitrifying, anammox, and sulfide-dependent denitrifying bacteria in the sediments of the seasonally hypoxic saline Lake Grevelingen, known to harbor an active microbial community involved in sulfur oxidation pathways. Depth distributions of 16S rRNA gene, nirS gene of denitrifying and anammox bacteria, aprA gene of sulfur-oxidizing and sulfate-reducing bacteria, and ladderane lipids of anammox bacteria were studied in sediments impacted by seasonally hypoxic bottom waters. Samples were collected down to 5 cm depth (1 cm resolution at three different locations before (March and during summer hypoxia (August. The abundance of denitrifying bacteria did not vary despite of differences in oxygen and sulfide availability in the sediments, whereas anammox bacteria were more abundant in the summer hypoxia but in those sediments with lower sulfide concentrations. The potential activity of denitrifying and anammox bacteria as well as of sulfur-oxidizing, including sulfide-dependent denitrifiers and sulfate-reducing bacteria, was potentially inhibited by the competition for nitrate and nitrite with cable and/or Beggiatoa-like bacteria in March and by the accumulation of sulfide in the summer hypoxia. The simultaneous presence and activity of organoheterotrophic denitrifying bacteria, sulfide-dependent denitrifiers and anammox bacteria suggests a tight network of bacteria coupling carbon-, nitrogen- and sulfur cycling in Lake Grevelingen sediments.

  9. Utilization of inorganic and organic nitrogen by bacteria in marine systems

    International Nuclear Information System (INIS)

    Wheeler, P.A.; Kirchman, D.L.

    1986-01-01

    The relative contribution of various inorganic and organic forms of nitrogen to the nitrogen requirements of picoplankton was examined with 15 N tracers. Size fractionation was used to measure uptake by <1-μm size microorganisms, and inhibitors of protein synthesis were used to separate procaryotic from eucaryotic nitrogen uptake. Picoplankton utilized mainly ammonium and amino acids and only negligible amounts of nitrate and urea. Nearly all amino acid uptake was by procaryotes, while both procaryotes and eucaryotes utilized ammonium. About 78% of total ammonium uptake was by procaryotes, and a significant portion of this was due specifically to heterotrophic bacteria. Regeneration of ammonium was correlated with eucaryotic rather than procaryotic activity. Ammonium accounted for at least 20-60% of the summed ammonium plus amino acid utilization by bacteria. The results suggest that significant portion of ammonium uptake in the euphotic zone was by heterotrophic bacteria rather than solely by phytoplankton. This may invalidate the use of the Redfield C:N ratio for estimating rates of nitrogen assimilation in the euphotic zone from carbon assimilation rates

  10. Exogenous fatty acid metabolism in bacteria.

    Science.gov (United States)

    Yao, Jiangwei; Rock, Charles O

    2017-10-01

    Bacterial type II fatty acid synthesis (FASII) is a target for novel antibiotic development. All bacteria encode for mechanisms to incorporate exogenous fatty acids, and some bacteria can use exogenous fatty acids to bypass FASII inhibition. Bacteria encode three different mechanisms for activating exogenous fatty acids for incorporation into phospholipid synthesis. Exogenous fatty acids are converted into acyl-CoA in Gammaproteobacteria such as E. coli. Acyl-CoA molecules constitute a separate pool from endogenously synthesized acyl-ACP. Acyl-CoA can be used for phospholipid synthesis or broken down by β-oxidation, but cannot be used for lipopolysaccharide synthesis. Exogenous fatty acids are converted into acyl-ACP in some Gram-negative bacteria. The resulting acyl-ACP undergoes the same fates as endogenously synthesized acyl-ACP. Exogenous fatty acids are converted into acyl-phosphates in Gram-positive bacteria, and can be used for phospholipid synthesis or become acyl-ACP. Only the order Lactobacillales can use exogenous fatty acids to bypass FASII inhibition. FASII shuts down completely in presence of exogenous fatty acids in Lactobacillales, allowing Lactobacillales to synthesize phospholipids entirely from exogenous fatty acids. Inhibition of FASII cannot be bypassed in other bacteria because FASII is only partially down-regulated in presence of exogenous fatty acid or FASII is required to synthesize essential metabolites such as β-hydroxyacyl-ACP. Certain selective pressures such as FASII inhibition or growth in biofilms can select for naturally occurring one step mutations that attenuate endogenous fatty acid synthesis. Although attempts have been made to estimate the natural prevalence of these mutants, culture-independent metagenomic methods would provide a better estimate. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  11. The ecological role of type three secretion systems in the interaction of bacteria with fungi in soil and related habitats is diverse and context-dependent

    NARCIS (Netherlands)

    Nazir, Rashid; Mazurier, Sylvie; Yang, Pu; Lemanceau, Philippe; van Elsas, Jan Dirk

    2017-01-01

    Bacteria and fungi constitute important organisms in many ecosystems, in particular terrestrial ones. Both organismal groups contribute significantly to biogeochemical cycling processes. Ecological theory postulates that bacteria capable of receiving benefits from host fungi are likely to evolve

  12. Sulfate-reducing bacteria in rice field soil and on rice roots.

    Science.gov (United States)

    Wind, T; Stubner, S; Conrad, R

    1999-05-01

    Rice plants that were grown in flooded rice soil microcosms were examined for their ability to exhibit sulfate reducing activity. Washed excised rice roots showed sulfate reduction potential when incubated in anaerobic medium indicating the presence of sulfate-reducing bacteria. Rice plants, that were incubated in a double-chamber (phylloshpere and rhizosphere separated), showed potential sulfate reduction rates in the anoxic rhizosphere compartment. These rates decreased when oxygen was allowed to penetrate through the aerenchyma system of the plants into the anoxic root compartment, indicating that sulfate reducers on the roots were partially inhibited by oxygen or that sulfate was regenerated by oxidation of reduced S-compounds. The potential activity of sulfate reducers on rice roots was consistent with MPN enumerations showing that H2-utilizing sulfate-reducing bacteria were present in high numbers on the rhizoplane (4.1 x 10(7) g-1 root fresh weight) and in the adjacent rhizosperic soil (2.5 x 10(7) g-1 soil dry weight). Acetate-oxidizing sulfate reducers, on the other hand, showed highest numbers in the unplanted bulk soil (1.9 x 10(6) g-1 soil dry weight). Two sulfate reducing bacteria were isolated from the highest dilutions of the MPN series and were characterized physiologically and phylogenetically. Strain F1-7b which was isolated from the rhizoplane with H2 as electron donor was related to subgroup II of the family Desulfovibrionaceae. Strain EZ-2C2, isolated from the rhizoplane on acetate, grouped together with Desulforhabdus sp. and Syntrophobacter wolinii. Other strains of sulfate-reducing bacteria originated from bulk soil of rice soil microcosms and were isolated using different electron donors. From these isolates, strains R-AcA1, R-IbutA1, R-PimA1 and R-AcetonA170 were Gram-positive bacteria which were affiliated with the genus Desulfotomaculum. The other isolates were members of subgroup II of the Desulfovibrionaceae (R-SucA1 and R-LacA1), were

  13. Sensitivity of certain bacteria to antibiotics and irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harsojo,; Andini, L S; Siagian, E G; Lina, M R; Zuleiha, S [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1981-07-01

    An experiment has been conducted to find vegetative forms of certain bacteria in Indonesia which are resistant to irradiation, the resistance of which will be compared to that of known radioresistant bacteria micrococcus radiodurans. To inactivate the vegetative forms of resistant bacteria to irradiation high doses are needed, while for storage purposes lower doses change the physical and chemical properties of the stored commodity are preferred. For this purpose the bacteria were irradiated in aerobic condition with gamma radiation doses of 0.1, 0.2 and 0.3 kGy, or treated with antibiotics e.g. tetracycline HCl or chloramphenicol with concentrations of 0.1, 0.2 and 0.3 ..mu..g/ml respectively. The results indicated that doses of 0.2 kGy and 0.1 ..mu..g/ml reduced the ability of the bacteria for multiplication.

  14. Cooccurrence patterns of plants and soil bacteria in the high-alpine subnival zone track environmental harshness

    Directory of Open Access Journals (Sweden)

    Andrew J. King

    2012-10-01

    Full Text Available Plants and soil microorganisms interact to play a central role in ecosystem functioning. To determine the potential importance of biotic interactions in shaping the distributions of these organisms in a high-alpine subnival landscape, we examine cooccurrence patterns between plant species and bulk-soil bacteria abundances. In this context, a cooccurrence relationship reflects a combination of several assembly processes: that both parties can disperse to the site, that they can survive the abiotic environmental conditions, and that interactions between the biota either facilitate survival or allow for coexistence. Across the entire landscape, 31% of the bacterial sequences in this dataset were significantly correlated to the abundance distribution of one or more plant species. These sequences fell into 14 clades, 6 of which are related to bacteria that are known to form symbioses with plants in other systems. Abundant plant species were more likely to have significant as well as stronger correlations with bacteria and these patterns were more prevalent in lower altitude sites. Conversely, correlations between plant species abundances and bacterial relative abundances were less frequent in sites near the snowline. Thus, plant-bacteria associations became more common as environmental conditions became less harsh and plants became more abundant. This pattern in cooccurrence strength and frequency across the subnival landscape suggests that plant-bacteria interactions are important for the success of life, both below- and above-ground, in an extreme environment.

  15. Anti-bacteria Effect of Active Ingredients of Cacumen Platycladi on the Spoilage Bacteria of Sauced Pork Head Meat

    Science.gov (United States)

    Li, Xiao; Xu, Lingyi; Cui, Yuqian; Pang, Meixia; Wang, Fang; Qi, Jinghua

    2017-12-01

    Extraction and anti-bacteria effect of active ingredients of Cacumen Platycladi were studied in this paper. Extraction combined with ultrasonic was adopted. The optimum extraction condition was determined by single factor test; the anti-bacteria effect of active ingredients and minimum inhibitory concentration(MIC) were valued by Oxford-cup method. The results indicated that kaempferol was the active ingredients of Cacumen Platycladi whose optimum extraction condition for ethanol concentrations were sixty-five percent and twenty minutes with ultrasonic assisted extraction.; the active ingredients of Cacumen Platycladi had anti-bacteria effect on Staphylococcus, Proteus, Bacillus, Serratia and MIC was 0.5 g/mL,0.5 g/mL,0.0313 g/mL and 0.0625 g/mL. The active constituent of Cacumen Platycladi is kaempferol which has obvious anti-bacteria effect and can be used to prolong the shelf-life of Low-temperature meat products.

  16. Behavior of plutonium interacting with bentonite and sulfate-reducing anaerobic bacteria

    International Nuclear Information System (INIS)

    Kudo, A.; Zheng, J.; Cayer, I.; Fujikawa, Y.; Yoshikawa, H.; Ito, M.

    1997-01-01

    The interactions between sulfate reducing anaerobic bacteria and plutonium, with or without bentonite present, were investigated using distribution coefficients [Kd (ml/g)] as an index of the radionuclide behavior. Plutonium Kds for living bacteria varied within a large range, from 1,804 to 112,952, depending on the pH, while the Kds ranged from 1,180 to 5,931 for dead bacteria. In general, living bacteria had higher plutonium Kds than dead bacteria. Furthermore, the higher Kd values of 39,677 to 106,915 for living bacteria were obtained for a pH range between 6.83 and 8.25, while no visible pH effect was observed for dead bacteria. These Kd values were obtained using tracers for both 236 Pu and 239 Pu, which can check the experimental procedures and mass balance. Another comparison was conducted for plutonium Kd values of mixtures of living bacteria with bentonite and sterilized bacteria with bentonite. The range of Kd values for the non-sterilized bacteria with bentonite were 1,194 to 83,648 while Kd values for the sterilized bacteria with bentonite were from 624 to 17,236. Again, the Kd values for the living bacteria with bentonite were higher than those of sterilized bacteria with bentonite. In other words, the presence of living anaerobic bacteria with bentonite increased, by roughly 50 times, the Kd values of 239 Pu when compared to the mixture of dead bacteria with bentonite. The results indicate that the effects of anaerobic bacteria within the engineered barrier system (in this case bentonite) will play a significant role in the behavior of plutonium in geologic repositories

  17. Multiresistant Bacteria Isolated from Chicken Meat in Austria

    Directory of Open Access Journals (Sweden)

    Gernot Zarfel

    2014-12-01

    Full Text Available Multidrug resistant bacteria (MDR bacteria, such as extended spectrum beta-lactamase (ESBL Enterobacteriaceae, methicillin resistant Staphylococcus aureus (MRSA, and vancomycin-resistant Enterococci (VRE, pose a challenge to the human health care system. In recent years, these MDR bacteria have been detected increasingly outside the hospital environment. Also the contamination of food with MDR bacteria, particularly of meat and meat products, is a concern. The aim of the study was to evaluate the occurrence of MDR bacteria in chicken meat on the Austrian market. For this study, 50 chicken meat samples were analysed. All samples originated from chickens slaughtered in Austrian slaughterhouses and were marked as produced in Austria. Samples were analysed for the presence of ESBL Enterobacteriaceae, methicillin resistant Staphylococci and VRE. Resistance genes of the isolated bacteria were characterised by PCR and sequencing. In the present study 26 ESBL producing E. coli, five mecA gene harbouring Staphylococci (but no MRSA, and four VRE were detected in chicken meat samples of Austrian origin. In 24 (48% of the samples no ESBL Enterobacteriaceae, MRSA, methicillin resistant coagulase negative Staphylococcus (MRCNS or VRE could be detected. None of the samples contained all three types of investigated multiresistant bacteria. In concordance to previous studies, CTX-M-1 and SHV-12 were the dominant ESBL genes.

  18. Pu sorption to activated conglomerate anaerobic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Kudo, Akira

    2001-01-01

    The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

  19. The effect of lactic acid bacteria on cocoa bean fermentation.

    Science.gov (United States)

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2015-07-16

    Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

  20. Seasonal variations of indoor microbial exposures and their relation to temperature, relative humidity, and air exchange rate.

    Science.gov (United States)

    Frankel, Mika; Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind; Madsen, Anne Mette

    2012-12-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m(3)) and were lowest in winter (median, 26 CFU/m(3)). Indoor bacteria peaked in spring (median, 2,165 CFU/m(3)) and were lowest in summer (median, 240 CFU/m(3)). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.

  1. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole...... weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment....

  2. Anaerobic ammonium oxidation by anammox bacteria in the Black Sea RID B-8834-2011

    DEFF Research Database (Denmark)

    Kuypers, MMM; Sliekers, AO; Lavik, G.

    2003-01-01

    The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions(1). The conversion of nitrate to N(2) by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean(2......). Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N(2) in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing...... the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors(3). Nutrient profiles, fluorescently labelled RNA probes, (15)N tracer experiments and the distribution of specific 'ladderane' membrane lipids(4) indicate that ammonium diffusing upwards from the anoxic deep water is consumed...

  3. Perchlorate reduction by hydrogen autotrophic bacteria and microbial community analysis using high-throughput sequencing.

    Science.gov (United States)

    Wan, Dongjin; Liu, Yongde; Niu, Zhenhua; Xiao, Shuhu; Li, Daorong

    2016-02-01

    Hydrogen autotrophic reduction of perchlorate have advantages of high removal efficiency and harmless to drinking water. But so far the reported information about the microbial community structure was comparatively limited, changes in the biodiversity and the dominant bacteria during acclimation process required detailed study. In this study, perchlorate-reducing hydrogen autotrophic bacteria were acclimated by hydrogen aeration from activated sludge. For the first time, high-throughput sequencing was applied to analyze changes in biodiversity and the dominant bacteria during acclimation process. The Michaelis-Menten model described the perchlorate reduction kinetics well. Model parameters q(max) and K(s) were 2.521-3.245 (mg ClO4(-)/gVSS h) and 5.44-8.23 (mg/l), respectively. Microbial perchlorate reduction occurred across at pH range 5.0-11.0; removal was highest at pH 9.0. The enriched mixed bacteria could use perchlorate, nitrate and sulfate as electron accepter, and the sequence of preference was: NO3(-) > ClO4(-) > SO4(2-). Compared to the feed culture, biodiversity decreased greatly during acclimation process, the microbial community structure gradually stabilized after 9 acclimation cycles. The Thauera genus related to Rhodocyclales was the dominated perchlorate reducing bacteria (PRB) in the mixed culture.

  4. A novel antimicrobial peptide against dental-caries-associated bacteria.

    Science.gov (United States)

    Chen, Long; Jia, Lili; Zhang, Qiang; Zhou, Xirui; Liu, Zhuqing; Li, Bingjie; Zhu, Zhentai; Wang, Fenwei; Yu, Changyuan; Zhang, Qian; Chen, Feng; Luo, Shi-Zhong

    2017-10-01

    Dental caries, a highly prevalent oral disease, is primarily caused by pathogenic bacteria infection, and most of them are anaerobic. Herein, we investigated the activity of a designed antimicrobial peptide ZXR-2, and found it showed broad-spectrum activity against a variety of Gram-positive and Gram-negative oral bacteria, particularly the caries-related taxa Streptococcus mutans. Time-course killing assays indicated that ZXR-2 killed most bacterial cells within 5 min at 4 × MIC. The mechanism of ZXR-2 involved disruption of cell membranes, as observed by scanning electron microscopy. Moreover, ZXR-2 inhibited the formation of S. mutans biofilm, but showed limited hemolytic effect. Based on its potent antimicrobial activity, rapid killing, and inhibition of S. mutans biofilm formation, ZXR-2 represents a potential therapeutic for the prevention and treatment of dental caries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

    Science.gov (United States)

    Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

    2012-07-01

    Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

  6. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. They divide by .... carry genetic material to the next generation through the process of reproduction; they are also .... molecules, and modified proteins. This report revealed that ...

  7. Platelets and infections—complex interactions with bacteria

    Directory of Open Access Journals (Sweden)

    Hind eHAMZEH-COGNASSE

    2015-02-01

    Full Text Available Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-Like Receptors but also integrins conventionally described in the hemostatic response, such as GPIIb-IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of Neutrophil Extracellular Traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet-bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the

  8. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  9. [Spectrum and susceptibility of preoperative conjunctival bacteria].

    Science.gov (United States)

    Fernández-Rubio, M E; Cuesta-Rodríguez, T; Urcelay-Segura, J L; Cortés-Valdés, C

    2013-12-01

    To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. A total of 13,203 bacteria were identified in 6,051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  10. Anti-bacterial effects of the essential oil of Teucrium polium L. on human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammad

    2013-09-01

    Results: The total oil content of Teucrium polium plant was 0.75%. Twenty eight compounds were identified in the essential oil that included 99.75% of the total oil. The major components were α-pinene (12.52%, Linalool (10.63% and Caryophyllene oxide (9.69%. For study of antimicrobial activity of the oil sample, the essential oil was tested against 9 bacteria by disc diffusion method. The antimicrobial effects of this essential oil was determined against three Gram positive bacteria Staphylococcus areous (PTCC 1431, Staphylococcus epidermidis (PTCC 1436, Streptococcus faecalis (PTCC 1237; as well as six Gram negative bacteria Pseudomonas aeroginosa (PTCC 11430, Shigella flexneri (PTCC 1716, Kellebsiella pneuomonae(PTCC=1053, Salmonella typhi (PTCC=1609, Serratia marcescens (PTCC 1187 and Escherichia coli (PTCC 1533. The antimicrobial effects of this essential oil on the Gram positive bacteria ( Staphylococcus aureus and Staphylococcus epidermidis and on all the Gram negative bacteria tested was much higher than those observed by tetracycline. Conclusions: The results showed the essential oil of Teucrium polium had strong anti-bacterial effects. The relatively high contents of α-pinene and Linalool in the essential oil may be the cause of its potential medicinal effects

  11. Using Bacteria to Store Renewable Energy (Text Version) | News | NREL

    Science.gov (United States)

    Using Bacteria to Store Renewable Energy (Text Version) Using Bacteria to Store Renewable Energy is a text version of the video entitled "Using Bacteria to Store Renewable Energy." ; Bacteria from some of the Earth's harshest environments now have a new home at NREL. [A natural spring has

  12. Electron microscopic examination of uncultured soil-dwelling bacteria.

    Science.gov (United States)

    Amako, Kazunobu; Takade, Akemi; Taniai, Hiroaki; Yoshida, Shin-ichi

    2008-05-01

    Bacteria living in soil collected from a rice paddy in Fukuoka, Japan, were examined by electron microscopy using a freeze-substitution fixation method. Most of the observed bacteria could be categorized, based on the structure of the cell envelope and overall morphology, into one of five groups: (i) bacterial spore; (ii) Gram-positive type; (iii) Gram-negative type; (iv) Mycobacterium like; and (v) Archaea like. However, a few of the bacteria could not be readily categorized into one of these groups because they had unique cell wall structures, basically resembling those of Gram-negative bacteria, but with the layer corresponding to the peptidoglycan layer in Gram-negative bacteria being extremely thick, like that of the cortex of a bacterial spore. The characteristic morphological features found in many of these uncultured, soil-dwelling cells were the nucleoid being in a condensed state and the cytoplasm being shrunken. We were able to produce similar morphologies in vitro using a Salmonella sp. by culturing under low-temperature, low-nutrient conditions, similar to those found in some natural environments. These unusual morphologies are therefore hypothesized to be characteristic of bacteria in resting or dormant stages.

  13. Bacteremias in liver transplant recipients: shift toward gram-negative bacteria as predominant pathogens.

    Science.gov (United States)

    Singh, Nina; Wagener, Marilyn M; Obman, Asia; Cacciarelli, Thomas V; de Vera, Michael E; Gayowski, Timothy

    2004-07-01

    During the 1990s, gram-positive bacteria emerged as major pathogens after liver transplantation. We sought to determine whether the pathogens associated with bacteremias in liver transplant recipients have changed. Patients included 233 liver transplant recipients transplanted between 1989 and 2003. The proportion of all infections due to bacteremias increased significantly over time (P gram-negatives increased from 25% in the period of 1989-1993 to 51.8% in 1998-03, that of gram-positive bacteria decreased from 75% in the period of 1989-93 to 48.2% in the period of 1998-2003. Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequent pathogens in bacteremic patients. The incidence of bacteremias due to MRSA and Pseudomonas aeruginosa has remained unchanged (P gram-negative bacteria, particularly Klebsiella pneumoniae has increased (P =.02). Klebsiella pneumoniae isolates in the current quartile were not clonally related. In conclusion, bacteremias as a proportion of all infections in liver transplant recipients have increased significantly over time, due in part to a decline in infections due to other major pathogens, e.g., fungi, primarily Candida species, and CMV. Gram-negative bacteria have emerged as predominant pathogens in bacteremic liver transplant recipients.

  14. Roseobacter-clade bacteria as probiotics in marine larvaeculture

    DEFF Research Database (Denmark)

    Grotkjær, Torben

    Disease caused by fish pathogenic bacteria can cause large scale crashes in marine fish larval rearing units. One of the biggest challenges for aquaculture is the management of these bacterial outbreaks. Vaccines can be admitted to fish but only the juvenile and the adult fish because they need...... to have a mature immune system. This means that the larvae of the fish, until they are 2-3 weeks old are more prone to bacterial infections. A short term solution is antibiotics but this leaves way for the selection for antibiotic resistance among the pathogenic bacteria, which again can be transferred...... to human pathogens. Alternatives are therefore needed and one could be the use of probiotic bacteria. Marine bacteria from the Roseobacter clade (Phaeobacter inhibens) have shown great potential as probiotic bacteria, and we have hypothesized that they could be used to antagonize pathogenic fish...

  15. AZF Microdeletions in Human Semen Infected with Bacteria

    Directory of Open Access Journals (Sweden)

    Hayfa H Hassani

    2011-11-01

    Full Text Available Bacterial infections are associated with infertility in men. This study was aimed to investigate microdeletions on Yq chromosome in semen infected with bacteria by using bacteriological, biochemical, and serological assays. The investigation showed that 107 of 300 (84.80% semen samples collected from infertile men with primary or secondary infertility were infected with different species of bacteria. Chlamydia trachomatis and Neisseria gonorrheae were the most frequently diagnosed bacteria in the infected semen samples. The percentages of infections of semen samples with C. trachomatis and N. gonorrhea were 42.31% and 35.28% respectively. Genomic DNA from each semen sample infected with predominant bacteria was analyzed for AZF deletions by using multiplex PCR. Different patterns of AZF microdeletions were obtained. It can be concluded that sexually transmitted bacteria may contribute in microdeletions of Yq chromosome by indirectly producing reactive oxygen species and causing gene defect in AZF regions.

  16. Beer-spoiling Ability of Lactic Acid Bacteria and its Relation with Genes horA, horC a hitA

    Czech Academy of Sciences Publication Activity Database

    Matoulková, D.; Kubizniaková, P.; Sigler, Karel

    2012-01-01

    Roč. 58, 11-12 (2012), s. 336-342 ISSN 0023-5830 R&D Projects: GA MŠk 1M0570 Institutional support: RVO:61388971 Keywords : beer spoilage * lactic acid bacteria Subject RIV: EE - Microbiology, Virology

  17. Two types of endosymbiotic bacteria in the enigmatic marine worm Xenoturbella

    DEFF Research Database (Denmark)

    Kjeldsen, Kasper Urup; Obst, Matthias; Nakano, Hiroaki

    2010-01-01

    Two types of endosymbiotic bacteria were identified in the gastrodermis of the marine invertebrate Xenoturbella bocki (Xenoturbellida, Bilateria). While previously described Chlamydia-like endosymbionts were rare, Gammaproteobacteria distantly related to other endosymbionts and pathogens were...... abundant. The endosymbionts should be considered when interpreting the poorly understood ecology and evolution of Xenoturbella....

  18. Desiccation: An environmental and food industry stress that bacteria commonly face.

    Science.gov (United States)

    Esbelin, Julia; Santos, Tiago; Hébraud, Michel

    2018-02-01

    Water is essential for all living organisms, for animals as well as for plants and micro-organisms. For these latter, the presence of water or a humid environment with a high air relative humidity (RH) is necessary for their survival and growth. Thus, variations in the availability of water or in the air relative humidity constitute widespread environmental stresses which challenge microorganisms, and especially bacteria. Indeed, in their direct environment, bacteria are often faced with conditions that remove cell-bound water through air-drying of the atmosphere. Bacterial cells are subject to daily or seasonal environmental variations, sometimes going through periods of severe desiccation. This is also the case in the food industry, where air dehumidification treatments are applied after the daily cleaning-disinfection procedures. In plants producing low-water activity products, it is also usual to significantly reduce or eliminate water usage. Periodic desiccation exposure affects bacteria viability and so they require strategies to persist. Negative effects of desiccation are wide ranging and include direct cellular damage but also changes in the biochemical and biophysical properties of cells for which planktonic cells are more exposed than cells in biofilm. Understanding the mechanisms of desiccation adaptation and tolerance has a biological and biotechnological interest. This review gives an overview of the factors influencing desiccation tolerance and the biological mechanisms involved in this stress response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R.R.

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  20. Methylotrophic bacteria in sustainable agriculture.

    Science.gov (United States)

    Kumar, Manish; Tomar, Rajesh Singh; Lade, Harshad; Paul, Diby

    2016-07-01

    Excessive use of chemical fertilizers to increase production from available land has resulted in deterioration of soil quality. To prevent further soil deterioration, the use of methylotrophic bacteria that have the ability to colonize different habitats, including soil, sediment, water, and both epiphytes and endophytes as host plants, has been suggested for sustainable agriculture. Methylotrophic bacteria are known to play a significant role in the biogeochemical cycle in soil ecosystems, ultimately fortifying plants and sustaining agriculture. Methylotrophs also improve air quality by using volatile organic compounds such as dichloromethane, formaldehyde, methanol, and formic acid. Additionally, methylotrophs are involved in phosphorous, nitrogen, and carbon cycling and can help reduce global warming. In this review, different aspects of the interaction between methylotrophs and host plants are discussed, including the role of methylotrophs in phosphorus acquisition, nitrogen fixation, phytohormone production, iron chelation, and plant growth promotion, and co-inoculation of these bacteria as biofertilizers for viable agriculture practices.

  1. Monitoring of airborne bacteria and aerosols in different wards of hospitals - Particle counting usefulness in investigation of airborne bacteria.

    Science.gov (United States)

    Mirhoseini, Seyed Hamed; Nikaeen, Mahnaz; Khanahmd, Hossein; Hatamzadeh, Maryam; Hassanzadeh, Akbar

    2015-01-01

    The presence of airborne bacteria in hospital environments is of great concern because of their potential role as a source of hospital-acquired infections (HAI). The aim of this study was the determination and comparison of the concentration of airborne bacteria in different wards of four educational hospitals, and evaluation of whether particle counting could be predictive of airborne bacterial concentration in different wards of a hospital. The study was performed in an operating theatre (OT), intensive care unit (ICU), surgery ward (SW) and internal medicine (IM) ward of four educational hospitals in Isfahan, Iran. A total of 80 samples were analyzed for the presence of airborne bacteria and particle levels. The average level of bacteria ranged from 75-1194 CFU/m (3) . Mean particle levels were higher than class 100,000 cleanrooms in all wards. A significant correlation was observed between the numbers of 1-5 µm particles and levels of airborne bacteria in operating theatres and ICUs. The results showed that factors which may influence the airborne bacterial level in hospital environments should be properly managed to minimize the risk of HAIs especially in operating theaters. Microbial air contamination of hospital settings should be performed by the monitoring of airborne bacteria, but particle counting could be considered as a good operative method for the continuous monitoring of air quality in operating theaters and ICUs where higher risks of infection are suspected.

  2. Isolation and Identification of Carcinogen Acenaphthene-Degrading Endemic Bacteria from Crude Oil Contaminated Soils around Abadan Refinery

    Directory of Open Access Journals (Sweden)

    Farshid Kafilzadeh

    2012-12-01

    Full Text Available Background and Objective: PAHs are non-polar organic compounds consisting of two or more fused benzene multi-rings. Among these compounds, acenaphthene is a multi-ring hydrocarbon that occurs abundantly in nature. Use of microorganisms to clean the contaminations of soil can be cheap and effective. The most important acenaphthene-degrading bacteria are pseudomonas, micrococcus, and Bacillus. The goal of this study was to isolate and identify the bacteria which degrade acenaphthene in soils around Abadan Refinery and to investigate the relation between the levels of environmental pollution with acenaphthene. Materials and Methods: Soil samples were collected from three areas around Abadan Refinery. The number of the bacteria was counted on the nutrient agar culture with and without acenaphthene. Isolation of the bacteria was done by culturing the samples on acenaphthene broth with a mineral-salt medium, and on an acenaphthene agar medium. Then, the bacteria were identified via biochemical diagnostic tests. Results: The logarithm average of the bacteria was 4.786 ± 0.073 at a medium with acenaphthene, which was 6.671 ± 0.073 less than that of the control medium. The maximum number of degrading bacteria was 7.089 ± 0.089 at Station C, and the minimum number of the degrading bacteria was 4.485 ± 0.089 at Station B. In this study, Bacillus sp, Micrococcus Luteus, Corynebacterium sp, Staphylococcus epidermidis, and Pseudomonas sp bacteria were isolated and identified in terms of frequency, respectively. Conclusion: The results of this study showed that the soil around Abadan Refinery contained a great number of acenaphthene degrading bacteria, especially Bacillus and Micrococcus.

  3. A novel surface-enhanced Raman scattering (SERS) detection for natural gas exploration using methane-oxidizing bacteria.

    Science.gov (United States)

    Liang, Weiwei; Chen, Qiao; Peng, Fang; Shen, Aiguo; Hu, Jiming

    2018-07-01

    Methane-oxidizing bacteria (MOB), a unique group of Gram-negative bacteria utilizing methane as a sole source of carbon and energy, have been proved to be a biological indicator for gas prospecting. Field and cultivation-free detection of MOB is important but still challenging in current microbial prospecting of oil and gas (MPOG) system. Herein, SERS was used for the first time to our knowledge to investigate two species of methanotrophs and four closely relevant bacteria that universally coexisted in the upper soil of natural gas. A special but very simple approach was utilized to make silver nanoparticles (Ag NPs) sufficiently contact with every single bacterial cell, and highly strong and distinct Raman signals free from any native fluorescence have been obtained, and successfully utilized for distinguishing MOB from other species. A more convincing multi-Raman criterion based on single Raman bands, and further the entire Raman spectrum in combination with statistical analysis (e.g., principal component analysis (PCA)), which were found capable of classifying MOB related bacterial cells in soil with an accuracy of 100%. This study therefore demonstrated sensitive and rapid SERS measurement technique accompanied by complete Raman database of various gas reservoirs related bacteria could aid field exploration of natural gas reservoir. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. In Situ Electron Microscopy of Lactomicroselenium Particles in Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Gabor Nagy

    2016-06-01

    Full Text Available Electron microscopy was used to test whether or not (a in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM to digital processing (dTEM, and further to remote-access internet electron microscopy (iTEM. Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200–350 nm than Lactobacillus casei (L. casei, which generated many, smaller lactomicroSel particles (85–200 nm and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60–280 nm in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100–500 nm, but higher relative to those isolated from Streptococcus thermopilus (50–100 nm. These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics.

  5. Epiphytic marine pigmented bacteria: A prospective source of natural antioxidants

    Directory of Open Access Journals (Sweden)

    Ravindra Pawar

    2015-03-01

    Full Text Available Awareness on antioxidants and its significance in human healthcare has increased many folds in recent time. Increased demand requisite on welcoming newer and alternative resources for natural antioxidants. Seaweed associated pigmented bacteria screened for its antioxidant potentials reveals 55.5% of the organisms were able to synthesize antioxidant compounds. DPPH assay showed 20% of the organisms to reach a antioxidant zone of 1 cm and 8.3% of the strains more than 3 cm. Pseudomonas koreensis (JX915782 a Sargassum associated yellowish brown pigmented bacteria have better activity than known commercial antioxidant butylated hydroxytoluene (BHT against DPPH scavenging. Serratia rubidaea (JX915783, an associate of Ulva sp. and Pseudomonas argentinensis (JX915781 an epiphyte of Chaetomorpha media, were also contributed significantly towards ABTS (7.2% ± 0.03 to 15.2 ± 0.09%; 1.8% ± 0.01 to 15.7 ± 0.22% and FRAP (1.81 ± 0.01 to 9.35 ± 0.98; 7.97 ± 0.12 to 18.70 ± 1.84 μg/mL of AsA Eq. respectively. 16S rRNA gene sequence analysis revealed bacteria that have higher antioxidant activity belongs to a bacterial class Gammaproteobacteria. Statistical analysis of phenolic contents in relation with other parameters like DPPH, ABTS, reducing power and FRAP are well correlated (p < 0.05. Results obtained from the current study inferred that the seaweed associated pigmented bacteria have enormous potential on antioxidant compounds and need to be extracted in a larger way for clinical applications.

  6. Transmission of nephridial bacteria of the earthworm Eisenia fetida.

    Science.gov (United States)

    Davidson, Seana K; Stahl, David A

    2006-01-01

    The lumbricid earthworms (annelid family Lumbricidae) harbor gram-negative bacteria in their excretory organs, the nephridia. Comparative 16S rRNA gene sequencing of bacteria associated with the nephridia of several earthworm species has shown that each species of worm harbors a distinct bacterial species and that the bacteria from different species form a monophyletic cluster within the genus Acidovorax, suggesting that there is a specific association resulting from radiation from a common bacterial ancestor. Previous microscopy and culture studies revealed the presence of bacteria within the egg capsules and on the surface of embryos but did not demonstrate that the bacteria within the egg capsule were the same bacteria that colonized the nephridia. We present evidence, based on curing experiments, in situ hybridizations with Acidovorax-specific probes, and 16S rRNA gene sequence analysis, that the egg capsules contain high numbers of the bacterial symbiont and that juveniles are colonized during development within the egg capsule. Studies exposing aposymbiotic hatchlings to colonized adults and their bedding material suggested that juvenile earthworms do not readily acquire bacteria from the soil after hatching but must be colonized during development by bacteria deposited in the egg capsule. Whether this is due to the developmental stage of the host or the physiological state of the symbiont remains to be investigated.

  7. THE TOXIC DINOFLAGELLATE GYMNODINIUM CATENATUM (DINOPHYCEAE) REQUIRES MARINE BACTERIA FOR GROWTH(1).

    Science.gov (United States)

    Bolch, Christopher J S; Subramanian, Thaila A; Green, David H

    2011-10-01

    Interactions with the bacterial community are increasingly considered to have a significant influence on marine phytoplankton populations. Here we used a simplified dinoflagellate-bacterium experimental culture model to conclusively demonstrate that the toxic dinoflagellate Gymnodinium catenatum H. W. Graham requires growth-stimulatory marine bacteria for postgermination survival and growth, from the point of resting cyst germination through to vegetative growth at bloom concentrations (10(3)  cells · mL(-1) ). Cysts of G. catenatum were germinated and grown in unibacterial coculture with antibiotic-resistant or antibiotic-sensitive Marinobacter sp. DG879 or Brachybacterium sp., and with mixtures of these two bacteria. Addition of antibiotics to cultures grown with antibiotic-sensitive strains of bacteria resulted in death of the dinoflagellate culture, whereas cultures grown with antibiotic-resistant bacteria survived antibiotic addition and continued to grow beyond the 21 d experiment. Removal of either bacterial type from mixed-bacterial dinoflagellate cultures (using an antibiotic) resulted in cessation of dinoflagellate growth until bacterial concentration recovered to preaddition concentrations, suggesting that the bacterial growth factors are used for dinoflagellate growth or are labile. Examination of published reports of axenic dinoflagellate culture indicate that a requirement for bacteria is not universal among dinoflagellates, but rather that species may vary in their relative reliance on, and relationship with, the bacterial community. The experimental model approach described here solves a number of inherent and logical problems plaguing studies of algal-bacterium interactions and provides a flexible and tractable tool that can be extended to examine bacterial interactions with other phytoplankton species. © 2011 Phycological Society of America.

  8. Electroactive biofilms of sulphate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Moura, Jose J.G. [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)], E-mail: jose.moura@dq.fct.unl.pt

    2008-12-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m{sup -2} that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces.

  9. Detection and Characterizations of Genes Resistant to Tetracycline and Sulfa among the Bacteria in Mariculture Water

    Science.gov (United States)

    Qu, L.; Li, Y.; Zhu, P.

    2013-12-01

    One hundred and thirty-five bacteria from maricultural environments were tested for sensitivity to tetracycline and sulfa. Result show that 72% of the bacteria were sulfa-resistant, 36% of the bacteria were tetracycline-resistant, and 16.5% of bacteria showed resistance to both tetracyclines and sulfa ,indicating that the proportion of sulfa and tetracycline resistance bacteria isvery large in the maricultural environments. PCR methods were used to detect if these resistant bacteria carry tetracycline and sulfa resistance genes. Out of the 33 tetracycline-resistant bacteria screened, 3 were positive for tetA, 6 were positive for tetB and no isolate wasboth positive for tetA and tetB. Of the 97 sulfa-resistant bacteria screened, 9 were positive for sul2, 6 were positive for sul1, 1 isolate was positive for bothsul1 and sul2. The minimum inhibitory concentration (MIC) of tetracycline for tetA-carrying isolates were higher than those tetB-carrying isolates.while The MIC of sulfa for sul2-carrying isolates were higher than those sul1-carrying isolates. Indicating that tetA and sul2 gene may play ubknown roles in resisting tetracycline and sulfa than tetB and sul1 genes. The results showed the 4 kinds of genes (tetA,tetB,sul1,sul2) has no host specificity. All these 16S sequence are from the isolates which are positive for the above genes, it indicated the above antibiotic resistance genes are widespread in the environment regardless of the host. While the DNA sequence of these four genes showed tetA, sul1, sul2 genes are conservative in different bacteria , etB gene conserved poorly. The research aim is to get a preliminary understanding of resistance mechanism related to the resistant bacteria and the resistance genes in marine aquaculture environment through the analysis of resistant genes, providing research base for the prevention and treatment of drug-resistant bacteria so as to reduce the threat to the ecological environment, aquaculture and human health.

  10. Community composition and cellulase activity of cellulolytic bacteria from forest soils planted with broad-leaved deciduous and evergreen trees.

    Science.gov (United States)

    Yang, Jiang-Ke; Zhang, Jing-Jing; Yu, Heng-Yu; Cheng, Jian-Wen; Miao, Li-Hong

    2014-02-01

    Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad

  11. Effect of radiation on activity of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Agaev, N.M.; Smorodin, A.E.; Gusejnov, M.M.

    1985-01-01

    The effect of γ-radiation on activity of sulphate reducing bacteria has been studied. Concentration of biogenic hydrogen, generated in the medium, is the main criterion, characterizing corrosion activity of the bacteria studied. The developed method of suppression of active development of sulfate reducing bacteria considerably reduces, and at lethal doses of γ-radiation eliminates altogether the bacteria activity and formation of the main corrosion agent-hydrogen sulphide-in the medium and that, in its turn, liquidates hydrogen sulphide corrosion

  12. Diversity and activity of methanotrophic related bacteria in subsurface sediments of the Krishna-Godavari Basin, India

    Digital Repository Service at National Institute of Oceanography (India)

    Sujith, P.P.; Sheba, M.; Gonsalves, M.J.B.D.

    system (Bio-Rad, USA). DNA sequencing and phylogenetic analysis: The ampli- fied PCR products were purified prior to sequencing according to the manufacturer’s guidelines, using the GenEluteTM PCR Cleanup Kit (Sigma, USA). The puri- fied PCR... at the interface between the reduced zones of the environment6 in the marine sediments7, where methane production and oxidation may take place. These bacteria can be obligate or facultative methano- trophs8. Based on their physiology and phylogeny...

  13. Rumen bacteria

    International Nuclear Information System (INIS)

    McSweeney, C.S.; Denman, S.E.; Mackie, R.I.

    2005-01-01

    The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methane-producing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 10 11 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (10 4 -10 6 /g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 10 2 -10 4 /g distributed over 5 genera). The occurrence of bacteriophage is well documented (10 7 -10 9 particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5

  14. Methods and Techniques of Sampling, Culturing and Identifying of Subsurface Bacteria

    International Nuclear Information System (INIS)

    Lee, Seung Yeop; Baik, Min Hoon

    2010-11-01

    This report described sampling, culturing and identifying of KURT underground bacteria, which existed as iron-, manganese-, and sulfate-reducing bacteria. The methods of culturing and media preparation were different by bacteria species affecting bacteria growth-rates. It will be possible for the cultured bacteria to be used for various applied experiments and researches in the future

  15. Encapsulation of bacteria and viruses in electrospun nanofibres

    International Nuclear Information System (INIS)

    Salalha, W; Kuhn, J; Dror, Y; Zussman, E

    2006-01-01

    Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1 kV cm -1 . Encapsulated bacteria in this work (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, λ) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55 deg. C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material

  16. Why bacteria matter in animal development and evolution.

    Science.gov (United States)

    Fraune, Sebastian; Bosch, Thomas C G

    2010-07-01

    While largely studied because of their harmful effects on human health, there is growing appreciation that bacteria are important partners for invertebrates and vertebrates, including man. Epithelia in metazoans do not only select their microbiota; a coevolved consortium of microbes enables both invertebrates and vertebrates to expand the range of diet supply, to shape the complex immune system and to control pathogenic bacteria. Microbes in zebrafish and mice regulate gut epithelial homeostasis. In a squid, microbes control the development of the symbiotic light organ. These discoveries point to a key role for bacteria in any metazoan existence, and imply that beneficial bacteria-host interactions should be considered an integral part of development and evolution.

  17. Quantification and Qualification of Bacteria Trapped in Chewed Gum

    NARCIS (Netherlands)

    Wessel, Stefan W.; van der Mei, Henny C.; Morando, David; Slomp, Anje M.; van de Belt-Gritter, Betsy; Maitra, Amarnath; Busscher, Henk J.

    2015-01-01

    Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and

  18. Bacteria associated with contamination of ready-to-eat (RTE ...

    African Journals Online (AJOL)

    The bacteria associated with contamination of ready-to-eat (RTE) cooked rice in Lagos, Nigeria were studied using standard microbiological methods. The objective of this study was to investigate the distribution of pathogenic bacteria recovered from RTE cooked rice in Lagos, assess bacteria load in the contaminated RTE ...

  19. 3D printing of bacteria into functional complex materials.

    Science.gov (United States)

    Schaffner, Manuel; Rühs, Patrick A; Coulter, Fergal; Kilcher, Samuel; Studart, André R

    2017-12-01

    Despite recent advances to control the spatial composition and dynamic functionalities of bacteria embedded in materials, bacterial localization into complex three-dimensional (3D) geometries remains a major challenge. We demonstrate a 3D printing approach to create bacteria-derived functional materials by combining the natural diverse metabolism of bacteria with the shape design freedom of additive manufacturing. To achieve this, we embedded bacteria in a biocompatible and functionalized 3D printing ink and printed two types of "living materials" capable of degrading pollutants and of producing medically relevant bacterial cellulose. With this versatile bacteria-printing platform, complex materials displaying spatially specific compositions, geometry, and properties not accessed by standard technologies can be assembled from bottom up for new biotechnological and biomedical applications.

  20. Diversity of both the cultivable protease-producing bacteria and bacterial extracellular proteases in the coastal sediments of King George Island, Antarctica.

    Directory of Open Access Journals (Sweden)

    Ming-Yang Zhou

    Full Text Available Protease-producing bacteria play a vital role in degrading sedimentary organic nitrogen. However, the diversity of these bacteria and their extracellular proteases in most regions remain unknown. In this paper, the diversity of the cultivable protease-producing bacteria and of bacterial extracellular proteases in the sediments of Maxwell Bay, King George Island, Antarctica was investigated. The cultivable protease-producing bacteria reached 10(5 cells/g in all 8 sediment samples. The cultivated protease-producing bacteria were mainly affiliated with the phyla Actinobacteria, Firmicutes, Bacteroidetes, and Proteobacteria, and the predominant genera were Bacillus (22.9%, Flavobacterium (21.0% and Lacinutrix (16.2%. Among these strains, Pseudoalteromonas and Flavobacteria showed relatively high protease production. Inhibitor analysis showed that nearly all the extracellular proteases from the bacteria were serine proteases or metalloproteases. These results begin to address the diversity of protease-producing bacteria and bacterial extracellular proteases in the sediments of the Antarctic Sea.

  1. [Teichoic acids from lactic acid bacteria].

    Science.gov (United States)

    Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

    2012-01-01

    The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

  2. High abundance and diversity of nitrite-dependent anaerobic methane-oxidizing bacteria in a paddy field profile.

    Science.gov (United States)

    Zhou, Leiliu; Wang, Yu; Long, Xi-En; Guo, Jianhua; Zhu, Guibing

    2014-11-01

    The discovery of nitrite-dependent anaerobic methane oxidation (n-damo) mediated by 'Candidatus Methylomirabilis oxyfera' with nitrite and methane as substrates has connected biogeochemical carbon and nitrogen cycles in a new way. The paddy fields often carry substantial methane and nitrate, thus may be a favorable habitat for n-damo bacteria. In this paper, the vertical-temporal molecular fingerprints of M. oxyfera-like bacteria, including abundance and community composition, were investigated in a paddy soil core in Jiangyin, near the Yangtze River. Through qPCR investigation, high abundance of M. oxyfera-like bacteria up to 1.0 × 10(8) copies (g d.w.s.)(-1) in summer and 8.5 × 10(7) copies (g d.w.s.)(-1) in winter was observed in the ecotone of soil and groundwater in the paddy soil core, which was the highest in natural environments to our knowledge. In the ecotone, the ratio of M. oxyfera-like bacteria to total bacteria reached peak values of 2.80% in summer and 4.41% in winter. Phylogenetic analysis showed n-damo bacteria in the paddy soil were closely related to M. oxyfera and had high diversity in the soil/groundwater ecotone. All of the results indicated the soil/groundwater ecotone of the Jiangyin paddy field was a favorable environment for the growth of n-damo bacteria. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. Degradation and utilization of polycyclic aromatic hydrocarbons by indigenous soil bacteria

    International Nuclear Information System (INIS)

    Stetzenbach, L.D.A.

    1986-01-01

    The persistence of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and noncontaminated sites contained 10 5 -10 7 viable microorganisms per gram dryweight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from uncontaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled 14 C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of 14 C into cellular biomass however was not observed during incubation of 14 C-anthracene in soil

  4. RpoS plays a central role in the SOS induction by sub-lethal aminoglycoside concentrations in Vibrio cholerae.

    Science.gov (United States)

    Baharoglu, Zeynep; Krin, Evelyne; Mazel, Didier

    2013-01-01

    Bacteria encounter sub-inhibitory concentrations of antibiotics in various niches, where these low doses play a key role for antibiotic resistance selection. However, the physiological effects of these sub-lethal concentrations and their observed connection to the cellular mechanisms generating genetic diversification are still poorly understood. It is known that, unlike for the model bacterium Escherichia coli, sub-minimal inhibitory concentrations (sub-MIC) of aminoglycosides (AGs) induce the SOS response in Vibrio cholerae. SOS is induced upon DNA damage, and since AGs do not directly target DNA, we addressed two issues in this study: how sub-MIC AGs induce SOS in V. cholerae and why they do not do so in E. coli. We found that when bacteria are grown with tobramycin at a concentration 100-fold below the MIC, intracellular reactive oxygen species strongly increase in V. cholerae but not in E. coli. Using flow cytometry and gfp fusions with the SOS regulated promoter of intIA, we followed AG-dependent SOS induction. Testing the different mutation repair pathways, we found that over-expression of the base excision repair (BER) pathway protein MutY relieved this SOS induction in V. cholerae, suggesting a role for oxidized guanine in AG-mediated indirect DNA damage. As a corollary, we established that a BER pathway deficient E. coli strain induces SOS in response to sub-MIC AGs. We finally demonstrate that the RpoS general stress regulator prevents oxidative stress-mediated DNA damage formation in E. coli. We further show that AG-mediated SOS induction is conserved among the distantly related Gram negative pathogens Klebsiella pneumoniae and Photorhabdus luminescens, suggesting that E. coli is more of an exception than a paradigm for the physiological response to antibiotics sub-MIC.

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

    Science.gov (United States)

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

    2012-10-01

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

  6. Use of thermophilic bacteria for bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    Al-Maghrabi, I.M.A.; Bin Aqil, A.O.; Chaalal, O.; Islam, M.R.

    1999-01-01

    Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60--80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. These bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreactor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mechanisms of bioremediation are identified

  7. Effects of ionizing radiation on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Suhadi, F [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1976-10-01

    The differences of radiosensitivities among bacteria in addition to the dependence upon the species or strains also depends on the environmental condition during irradiation (temperature, medium, the presence of protective or sensitizing agents, the gas phase or atmosphere, and water activity, or degree of hydration) and on the effects of the environmental condition before and after irradiation treatment (temperature of incubation, age of culture and growth medium). In general, spores are more resistant to radiation than vegetatic bacteria, with the exception that a few cocci are the most radiation resistant bacteria (Micrococcus and Streptococcus). The application of ionizing radiation in the fields of microbiology supports the radiation sterilization of medical and pharmaceutical products. In addition, microbiological aspects of food preservation, especially radurization, radicidation, and immunization studies by using irradiated microorganisms, are also important.

  8. Lethal photosensitization of biofilm-grown bacteria

    Science.gov (United States)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  9. Isolation And Partial Characterization Of Bacteria Activity Associated With Gorgonian Euplexaura sp. Against Methicillin-Resistant Staphylococcus aureus (MRSA)

    Science.gov (United States)

    Kristiana, R.; Ayuningrum, D.; Asagabaldan, M. A.; Nuryadi, H.; Sabdono, A.; Radjasa, O. K.; Trianto, A.

    2017-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infection has emerged in around the world and has been resistance to ciprofloxacin, erythromycin, clindamycin. The aims of this study were to isolate, to investigate and to characterize bacterial symbionts gorgonian having activity against MRSA. Euplexaura sp. was collected from Panjang Island, Jepara, Indonesia by snorkling 2-5 m in depth. Bacterias were isolated by using spesific media with dilution method. Bacterias were conducted by using the streak method. Antibacterial activity was investigated by overlay method. The potent bacteria was identified by using molecular identification (DNA extraction, electrophoresis, PCR and phylogenetic analysis using 16S rDNA genes with actinobacteria-spesific primers) and bio-chemical test (among 5 isolated bacteria from gorgonian showed activity against MRSA). The strain PG-344 was the best candidat that has an inhibition zone against MRSA. The result of sequencing bacteria is 100% closely related with Virgibacillus salarius. This becomes a potential new bioactive compounds to against MRSA that can be a new drug discovery.

  10. Analyzing Arthropods for the Presence of Bacteria

    OpenAIRE

    Andrews, Elizabeth S.

    2013-01-01

    Bacteria within arthropods can be identified using culture-independent methods. This unit describes protocols for surface sterilization of arthropods, DNA extraction of whole bodies and tissues, touchdown PCR amplification using 16S rDNA general bacteria primers and profiling the bacterial community using denaturing gradient gel electrophoresis.

  11. Isolation and characterization of autotrophic, hydrogen-utilizing, perchlorate-reducing bacteria.

    Science.gov (United States)

    Shrout, Joshua D; Scheetz, Todd E; Casavant, Thomas L; Parkin, Gene F

    2005-04-01

    Recent studies have shown that perchlorate (ClO(4) (-)) can be degraded by some pure-culture and mixed-culture bacteria with the addition of hydrogen. This paper describes the isolation of two hydrogen-utilizing perchlorate-degrading bacteria capable of using inorganic carbon for growth. These autotrophic bacteria are within the genus Dechloromonas and are the first Dechloromonas species that are microaerophilic and incapable of growth at atmospheric oxygen concentrations. Dechloromonas sp. JDS5 and Dechloromonas sp. JDS6 are the first perchlorate-degrading autotrophs isolated from a perchlorate-contaminated site. Measured hydrogen thresholds were higher than for other environmentally significant, hydrogen-utilizing, anaerobic bacteria (e.g., halorespirers). The chlorite dismutase activity of these bacteria was greater for autotrophically grown cells than for cells grown heterotrophically on lactate. These bacteria used fumarate as an alternate electron acceptor, which is the first report of growth on an organic electron acceptor by perchlorate-reducing bacteria.

  12. Antibiotic-producing bacteria from stag beetle mycangia.

    Science.gov (United States)

    Miyashita, Atsushi; Hirai, Yuuki; Sekimizu, Kazuhisa; Kaito, Chikara

    2015-02-01

    The search for new antibiotics or antifungal agents is crucial for the chemotherapies of infectious diseases. The limited resource of soil bacteria makes it difficult to discover such new drug candidate. We, therefore, focused on another bacterial resource than soil bacteria, the microbial flora of insect species. In the present study, we isolated 40 strains of bacteria and fungi from the mycangia of three species of stag beetle, Dorcus hopei binodulosus, Dorcus rectus, and Dorcus titanus pilifer. We identified those species with their ribosomal DNA sequences, and revealed that Klebsiella spp. are the most frequent symbiont in the stag beetle mycangia. We examined whether these microorganisms produce antibiotics against a Gram-negative bacterium, Escherichia coli, a Gram-positive bacterium, Staphylococcus aureus, or a fungus, Cryptococcus neoformans. Culture supernatants from 33, 29, or 18 strains showed antimicrobial activity against E. coli, S. aureus, or C. neoformans, respectively. These findings suggest that bacteria present in the mycangia of stag beetles are useful resources for screening novel antibiotics.

  13. Screening identification of aerobic denitrification bacteria with high soil desalinization capacity

    Science.gov (United States)

    Jin, H.; Chen, H.; Jin, H.; Qian, Y.; Zhang, K.

    2017-08-01

    In order to study the mechanism of bacteria used in the saline soil remediation process, the aerobic denitrification bacteria were isolated from an agricultural greenhouse soil in a farm in East China’s Zhejiang Province. The identification, nitrogen reducing characteristics and the denitrification effect of bacteria from different soils at various locations were investigated. The results showed that the NO3- removal rate was 91% with bacteria from the greenhouse soil under aerobic conditions in 52 h, and the bacteria were identified as Gram-positive Castellaniella denitrification bacteria.

  14. Working with bacteria and putting bacteria to work: The biopolitics of synthetic biology for energy in the United Kingdom.

    Science.gov (United States)

    McLeod, Carmen; Nerlich, Brigitte; Mohr, Alison

    2017-08-01

    The UK government has made significant investment into so called 'fourth-generation' biofuel technologies. These biofuels are based on engineering the metabolic pathways of bacteria in order to create products compatible with existing infrastructure. Bacteria play an important role in what is promoted as a potentially new biological industrial revolution, which could address some of the negative environmental legacies of the last. This article presents results from ethnographic research with synthetic biologists who are challenged with balancing the curiosity-driven and intrinsically fulfilling scientific task of working with bacteria, alongside the policy-driven task of putting bacteria to work for extrinsic economic gains. In addition, the scientists also have to balance these demands with a new research governance framework, Responsible Research and Innovation, which envisions technoscientific innovation will be responsive to societal concerns and work in collaboration with stakeholders and members of the public. Major themes emerging from the ethnographic research revolve around stewardship, care, responsibility and agency. An overall conflict surfaces between individual agents assuming responsibility for 'stewarding' bacteria, against funding systems and structures imposing responsibility for economic growth. We discuss these findings against the theoretical backdrop of a new concept of 'energopolitics' and an anthropology of ethics and responsibility.

  15. Association of red complex, A. actinomycetemcomitans and non-oral bacteria with periodontal diseases.

    Science.gov (United States)

    da Silva-Boghossian, Carina Maciel; do Souto, Renata Martins; Luiz, Ronir R; Colombo, Ana Paula Vieira

    2011-09-01

    Pathogens related to systemic infections have been detected in the periodontal microbiota. The relationship amongst these pathogens, periodontal bacteria and periodontal clinical status is poorly understood. This study evaluated the association amongst red complex, A. actinomycetemcomitans (A.a) and non-oral pathogenic bacteria in subjects with good periodontal health (PH), gingivitis (G), chronic (CP) and aggressive (AP) periodontitis. Subgingival biofilm samples were obtained from 51 PH, 42 G, 219 CP and 90 AP subjects. The presence and levels of A.a, red complex (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola), Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus were determined by DNA probes and DNA-DNA hybridization technique. CP and AP subjects presented significantly higher prevalence and levels of A.a, red complex and A. baumannii than G and PH individuals (pperiodontal disease (pperiodontal pathogens and non-oral bacteria alone or in association were strongly associated with periodontitis. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Proteomic insights into intra- and intercellular plant-bacteria symbiotic association during root nodule formation

    Directory of Open Access Journals (Sweden)

    Afshin eSalavati

    2013-02-01

    Full Text Available Over the last several decades, there have been a large number of studies done on the all aspects of legumes and bacteria which participate in nitrogen-fixing symbiosis. The analysis of legume-bacteria interaction is not just a matter of numerical complexity in terms of variants of gene products that can arise from a single gene. Bacteria regulate their quorum-sensing genes to enhance their ability to induce conjugation of plasmids and symbiotic islands, and various protein secretion mechanisms; that can stimulate a collection of chain reactions including species-specific combinations of plant-secretion isoflavonoids, complicated calcium signaling pathways and autoregulation of nodulation mechanisms. Quorum-sensing systems are introduced by the intra- and intercellular organization of gene products lead to protein–protein interactions or targeting of proteins to specific cellular structures. In this study, an attempt has been made to review significant contributions related to nodule formation and development and their impacts on cell proteome for better understanding of plant-bacterium interaction mechanism at protein level. This review would not only provide new insights into the plant-bacteria symbiosis response mechanisms but would also highlights the importance of studying changes in protein abundance inside and outside of cells in response to symbiosis. Furthermore, the application to agriculture programe of plant-bacteria interaction will be discussed.

  17. DEVELOPMENT OF TOFU PRODUCTION METHOD WITH PROBIOTIC BACTERIA ADDITION

    Directory of Open Access Journals (Sweden)

    Dorota Zielińska

    2015-06-01

    Full Text Available The aim of the study was to develop a production method for tofu with probiotic bacteria under laboratory conditions. The works included: selection of a strain and tofu production conditions, and a storage test of the manufactured product. It was concluded that the sensory quality of tofu with the addition of different probiotic cultures did not differ significantly (p>0.01, depending on used strains and their mixtures, and the sample quality was comparable to the commercial product. It was observed that the number of Lactobacillus bacteria in study samples was the factor determining the palatability of tofu (r= 0.75. On the other hand, the sensory quality of products was significantly affected by the production method of tofu with the addition of probiotic bacteria. It was concluded that the formation of curds from soy beverage by the addition of CaSO4, followed by inoculation with Lactobacillus casei ŁOCK 0900 at the amount of 9.26 log CFU/g and incubation at temp. of 37C for 2h as well as for 20h are methods recommended for production tofu with regard to sensory qualities of the final product among all tested methods. The number of lactic acid bacteria in studied tofu samples was maintained at the high level (109-1010 CFU/g, and the number of Bifidobacterium animalis ssp lactis BB-12 bacteria did not exceed 103 CFU/g, whereas the number of Lactobacillus bacteria was equal to 108-109 CFU/g. For the period of 15 days of storage of tofu with probiotic bacteria at the temperature of 4C the number of lactic acid bacteria was maintained at the constant level of approx. 109 CFU/g. It was concluded that it is possible to produce tofu with probiotic bacteria that has acceptable sensory characteristics and a high number of lactic acid bacteria, therefore the product could be considered as a functional one.

  18. Diversity and numbers of root-nodule bacteria (rhizobia in Polish soils

    Directory of Open Access Journals (Sweden)

    Stefan Martyniuk

    2011-01-01

    Full Text Available Using a sand pouch-plant infection method, populations of several species of root-nodule bacteria (rhizobia were enumerated in eighty soils collected throughout Poland. Rhizobium leguminosarum bv. viciae (symbionts of pea, faba bean, vetch and R. leguminosarum bv. trifolii (symbionts of clover were detected in 77 and 76 soils, respectively. Most of these soils contained moderate and high numbers of these species of the rhizobia. Symbionts of beans, R. leguminosarum bv. phaseoli, were assessed in 76 soils; of this number 15 soils had no detectable populations of bean rhizobia and in 40 soils high or moderate numbers of these bacteria were found. Bradyrhizobium sp. (Lupinus, root-nodule bacteria of lupine and serradella, were absent in 19 soils, out of 80 tested, and 34 soils were colonised by high or moderate populations of bradyrhizobia. Sinorhizobium meliloti, rhizobia nodulating alfalfa, were sparse in the examined soils; with 56 soil containing no detectable numbers of S. meliloti and only 6 soils harbouring high or moderate populations of this species. The estimated numbers of the rhizobia in the studied soils were also related to some physical and chemical properties of these soils.

  19. Purification of bacteriocins produced by lactic acid bacteria.

    Science.gov (United States)

    Saavedra, Lucila; Castellano, Patricia; Sesma, Fernando

    2004-01-01

    Bacteriocins are antibacterial substances of a proteinaceous nature that are produced by different bacterial species. Lactic acid bacteria (LAB) produce biologically active peptides or protein complexes that display a bactericidal mode of action almost exclusively toward Gram-positive bacteria and particularly toward closely related species. Generally they are active against food spoilage and foodborne pathogenic microorganisms including Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, and Listeria monocytogenes. There is an increased tendency to use natural occurring metabolites to prevent the growth of undesirable flora in foodstuffs. These metabolites could replace the use of chemical additives such as sorbic acid, sulfur dioxide, nitrite, nitrate, and others. For instance, bacteriocins produced by LAB may be promising for use as bio-preservaties. Bacteriocins of lactic acid bacteria are typically cationic, hydrophobic peptides and differ widely in many characteristics including molecular weight, presence of particular groups of amino acids, pI, net positive charge, and post-translational modifications of certain amino acids. This heterogeneity within the LAB bacteriocins may explain the different procedures for isolation and purification developed so far. The methods most frequently used for isolation, concentration, and purification involve salt precipitation of bacteriocins from culture supernatants, followed by various combinations of gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). In this chapter, a protocol is described that combines several methods used in our laboratory for the purification of two cationic bacteriocins, Lactocin 705AL and Enterocin CRL10, produced by Lactobacillus casei CRL705 and Enterococcus mundtii CRL10, respectively.

  20. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    Directory of Open Access Journals (Sweden)

    André Horta

    2014-03-01

    Full Text Available Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1 extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity and oxygen radical absorbance capacity (ORAC. Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%, Alteromonas sp. (12.82%, Shewanella sp. (12.26%, Serratia sp. (2.56%, Citricoccus sp. (2.56%, Cellulophaga sp. (2.56%, Ruegeria sp. (2.56% and Staphylococcus sp. (2.56%. Six (15.38% of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis was exhibited by strain 16 (Shewanella sp.. Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

  1. Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteria.

    Science.gov (United States)

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-03-24

    Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

  2. Stalking Antibiotic-Resistant Bacteria in Common Vegetables

    Science.gov (United States)

    Brock, David; Boeke, Caroline; Josowitz, Rebecca; Loya, Katherine

    2004-01-01

    The study developed a simple experimental protocol for studying antibiotic resistant bacteria that will allow students to determine the proportion of such bacteria found on common fruit and vegetable crops. This protocol can open up the world of environmental science and show how human behavior can dramatically alter ecosystems.

  3. Contribution of bacteria-like particles to PM2.5 aerosol in urban and rural environments

    Science.gov (United States)

    Wolf, R.; El-Haddad, I.; Slowik, J. G.; Dällenbach, K.; Bruns, E.; Vasilescu, J.; Baltensperger, U.; Prévôt, A. S. H.

    2017-07-01

    We report highly time-resolved estimates of airborne bacteria-like particle concentrations in ambient aerosol using an Aerodyne aerosol mass spectrometer (AMS). AMS measurements with a newly developed PM2.5 and the standard (PM1) aerodynamic lens were performed at an urban background site (Zurich) and at a rural site (Payerne) in Switzerland. Positive matrix factorization using the multilinear engine (ME-2) implementation was used to estimate the contribution of bacteria-like particles to non-refractory organic aerosol. The success of the method was evaluated by a size-resolved analysis of the organic mass and the analysis of single particle mass spectra, which were detected with a light scattering system integrated into the AMS. Use of the PM2.5 aerodynamic lens increased measured bacteria-like concentrations, supporting the analysis method. However, at all sites, the low concentrations of this component suggest that airborne bacteria constitute a minor fraction of non-refractory PM2.5 organic aerosol mass. Estimated average mass concentrations were below 0.1 μg/m3 and relative contributions were lower than 2% at both sites. During rainfall periods, concentrations of the bacteria-like component increased considerably reaching a short-time maximum of approximately 2 μg/m3 at the Payerne site in summer.

  4. Effect of ionizing radiation on the antigenic composition of typhoid bacteria

    International Nuclear Information System (INIS)

    Sinilova, N.G.; Nikolaeva, L.A.; Tumanyan, M.A.

    1978-01-01

    Changes in the antigenic composition of typhoid bacteria occurring during the exposure of microbial suspension to different doses of gamma radiation ( 60 Co) ranging between 0.5 and 3.0 Mrad were studied. Immunoelectrophoresis in agar was used to determine the antigenic composition of different samples of irradiated bacteria. The antigenic composition of bacteria irradiated with doses up to 2.5 Mrad was found to be similar to that of non-irradiated bacteria. Antigens demonstrated by means of Vi, H and O antisera are preserved in these bacteria. However, all irradiated bacteria in general slightly differ from non-irradiated bacteria; this is manifest in a different configuration and position of the precipitation lines in the cathodic part of the immunophoreograms. The content of the component migrating rapidly towards the cathode, evidently the O antigen in the R form, in the irradiated bacteria increases with the dose of radiation. No new serologically active substances, non-existent in non-irradiated bacteria, were found to appear in the process of irradiation. (author)

  5. Reducing gas content of coal deposits by means of bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Lipowa, A A; Kozlowski, B

    1981-07-01

    This paper discusses the results of experiments carried out in Poland under laboratory conditions on efficiency of methane control using bacteria from Methanosarcina and Methanomonas groups. Malashenko and Whittenburry culture mediums were used. Bacteria growth in an atmosphere of air and methane (48.2%, 8.6% and 5.21%) was observed. Temperature ranged from 19 to 20 C. Investigations show that the bacteria are characterized by high oxidation activity. Depending on methane concentration in the air the bacteria consume from 75% to 100% of methane during biosynthesis. The bacteria reduce methane and oxygen content and increase carbon dioxide content in the air. Using bacteria methane concentration in the air was reduced from 48.2% to 12.3%, from 8.6% to 0.0% and from 5.21% to 0.01%. (7 refs.) (In Polish)

  6. Novel Adaptive Bacteria Foraging Algorithms for Global Optimization

    Directory of Open Access Journals (Sweden)

    Ahmad N. K. Nasir

    2014-01-01

    Full Text Available This paper presents improved versions of bacterial foraging algorithm (BFA. The chemotaxis feature of bacteria through random motion is an effective strategy for exploring the optimum point in a search area. The selection of small step size value in the bacteria motion leads to high accuracy in the solution but it offers slow convergence. On the contrary, defining a large step size in the motion provides faster convergence but the bacteria will be unable to locate the optimum point hence reducing the fitness accuracy. In order to overcome such problems, novel linear and nonlinear mathematical relationships based on the index of iteration, index of bacteria, and fitness cost are adopted which can dynamically vary the step size of bacteria movement. The proposed algorithms are tested with several unimodal and multimodal benchmark functions in comparison with the original BFA. Moreover, the application of the proposed algorithms in modelling of a twin rotor system is presented. The results show that the proposed algorithms outperform the predecessor algorithm in all test functions and acquire better model for the twin rotor system.

  7. [Effects of transgenic Bt + CpTI cotton on rhizosphere bacteria and ammonia oxidizing bacteria population].

    Science.gov (United States)

    Dong, Lianhua; Meng, Ying; Wang, Jing

    2014-03-04

    The effect of transgenic cotton on the rhizosphere bacteria can be important to the risk assessment for the genetically modified crops. We studied the rhizosphere microbial community with cultivating genetically modified cotton. The effects of transgenic Bt + CpTI Cotton (SGK321) and its receptor cotton (SY321) on rhizosphere total bacteria and ammonia oxidizing bacteria population size were studied by using droplet digital PCR. We collected rhizosphere soil before cotton planting and along with the cotton growth stage (squaring stage, flowering stage, belling stage and boll opening stage). There was no significant change on the total bacterial population between the transgenic cotton and the receptor cotton along with the growth stage. However, the abundance of ammonia oxidizing bacteria (AOB) in both type of cottons showed significant difference between different growth stages, and the variation tendency was different. In squaring stage, the numbers of AOB in rhizosphere of SY321 and SGK321 increased 4 and 2 times, respectively. In flowering stage, AOB number in rhizosphere of SY321 significantly decreased to be 5.96 x 10(5) copies/g dry soil, however, that of SGK321 increased to be 1.25 x 10(6) copies/g dry soil. In belling stage, AOB number of SY321 greatly increased to be 1.49 x 10(6) copies/g dry soil, but no significant change was observed for AOB number of SGK321. In boll opening stage, both AOB number of SY321 and SGK321 clearly decreased and they were significantly different from each other. Compared to the non-genetically modified cotton, the change in abundance of ammonia oxidizing bacteria was slightly smooth in the transgenic cotton. Not only the cotton growth stage but also the cotton type caused this difference. The transgenic cotton can slow down the speed of ammonia transformation through impacting the number of AOB, which is advantageous for plant growth.

  8. Some physiological and morphological aspects of radiation-resistant bacteria and a new method for their isolation from food

    International Nuclear Information System (INIS)

    Sanders, S.W.

    1978-01-01

    A study was undertaken to help clarify the taxonomic positions and mechanisms of radiation resistance of radiation-resistant asporogenous bacteria found in foods. Determinations of DNA base compositions of highly resistant Moroxella-Acinetobacter (M-A) strains indicated that they were atypical, having percent guanine plus cytosine contents exceeding the values for true Moraxella or Acinetobacter spp. By direct observation of dividing cells, the resistant M-A were found to undergo multiple-plane division. Electron micrographs revealed unusually thick cell walls in the M-A as compared with gram-negative bacteria, indicating a possible role of the cell wall in radiation resistance. Resistance to desiccation was utilized in the selection of highly radiation-resistant bacteria from non-irradiated sources. Bacteria from a food or other source were suspended in dilute phosphate buffer and dried in a thin film at 25 C and 33% relative humidity. Storage under these conditions for 15 days or more reduced the numbers of radiation-sensitive bacteria. Further selection of the most radiation-resistant bacteria was obtained by irradiation of bacteria on velveteen in the replication process, thereby allowing the isolation of highly resistant bacteria that had not been irradiated. The similarity of radiation-resistance and identifying characteristics between irradiated and non-irradiated isolates indicated that highly radiation-resistant bacteria are not altered by radiation selection. Irradiated Plate Count Agar and Tryptic Soy Agar were found to be very toxic to radiation-resistant bacteria. This phenomenon may be important in food irradiation, where the ability to survive and grow in a product may depend partly on the sensitivity to bacteriocidal products formed during irradiation

  9. Molecular diversity of legume root-nodule bacteria in Kakadu National Park, Northern Territory, Australia.

    Directory of Open Access Journals (Sweden)

    Bénédicte Lafay

    2007-03-01

    Full Text Available Symbiotic relationships between leguminous plants (family Fabaceae and nodule-forming bacteria in Australia native ecosystems remain poorly characterized despite their importance. Most studies have focused on temperate parts of the country, where the use of molecular approaches have already revealed the presence of Bradyrhizobium, Ensifer (formerly Sinorhizobium, Mesorhizobium and Rhizobium genera of legume root-nodule bacteria. We here provide the first molecular characterization of nodulating bacteria from tropical Australia.45 nodule-forming bacterial strains, isolated from eight native legume hosts at eight locations in Kakadu National Park, Northern Territory, Australia, were examined for their genetic diversity and phylogenetic position. Using SSU rDNA PCR-RFLPs and phylogenetic analyses, our survey identified nine genospecies, two of which, Bradyrhizobium genospp. B and P, had been previously identified in south-eastern Australia and one, Mesorhizobium genospecies AA, in southern France. Three of the five newly characterized Bradyrhizobium genospecies were more closely related to B. japonicum USDA110, whereas the other two belonged to the B. elkanii group. All five were each more closely related to strains sampled in various tropical areas outside Australia than to strains known to occur in Australia. We also characterized an entirely novel nodule-forming lineage, phylogenetically distant from any previously described rhizobial and non-rhizobial legume-nodulating lineage within the Rhizobiales.Overall, the present results support the hypothesis of tropical areas being centres of biodiversity and diversification for legume root-nodule bacteria and confirm the widespread occurrence of Bradyrhizobium genosp. B in continental Australia.

  10. Significance of anaerobes and oral bacteria in community-acquired pneumonia.

    Directory of Open Access Journals (Sweden)

    Kei Yamasaki

    Full Text Available BACKGROUND: Molecular biological modalities with better detection rates have been applied to identify the bacteria causing infectious diseases. Approximately 10-48% of bacterial pathogens causing community-acquired pneumonia are not identified using conventional cultivation methods. This study evaluated the bacteriological causes of community-acquired pneumonia using a cultivation-independent clone library analysis of the 16S ribosomal RNA gene of bronchoalveolar lavage specimens, and compared the results with those of conventional cultivation methods. METHODS: Patients with community-acquired pneumonia were enrolled based on their clinical and radiological findings. Bronchoalveolar lavage specimens were collected from pulmonary pathological lesions using bronchoscopy and evaluated by both a culture-independent molecular method and conventional cultivation methods. For the culture-independent molecular method, approximately 600 base pairs of 16S ribosomal RNA genes were amplified using polymerase chain reaction with universal primers, followed by the construction of clone libraries. The nucleotide sequences of 96 clones randomly chosen for each specimen were determined, and bacterial homology was searched. Conventional cultivation methods, including anaerobic cultures, were also performed using the same specimens. RESULTS: In addition to known common pathogens of community-acquired pneumonia [Streptococcus pneumoniae (18.8%, Haemophilus influenzae (18.8%, Mycoplasma pneumoniae (17.2%], molecular analysis of specimens from 64 patients with community-acquired pneumonia showed relatively higher rates of anaerobes (15.6% and oral bacteria (15.6% than previous reports. CONCLUSION: Our findings suggest that anaerobes and oral bacteria are more frequently detected in patients with community-acquired pneumonia than previously believed. It is possible that these bacteria may play more important roles in community-acquired pneumonia.

  11. Bactericidal effects of antibiotics on slowly growing and nongrowing bacteria.

    OpenAIRE

    Eng, R H; Padberg, F T; Smith, S M; Tan, E N; Cherubin, C E

    1991-01-01

    Antimicrobial agents are most often tested against bacteria in the log phase of multiplication to produce the maximum bactericidal effect. In an infection, bacteria may multiply less optimally. We examined the effects of several classes of antimicrobial agents to determine their actions on gram-positive and gram-negative bacteria during nongrowing and slowly growing phases. Only ciprofloxacin and ofloxacin exhibited bactericidal activity against nongrowing gram-negative bacteria, and no antib...

  12. Molecular and phenotypic characterization of endophytic bacteria isolated from sulla nodules.

    Science.gov (United States)

    Beghalem, Hamida; Aliliche, Khadidja; Chriki, Ali; Landoulsi, Ahmed

    2017-10-01

    In the current study, bacterial diversity was investigated in root nodules of Sulla pallida and Sulla capitata. The isolates were analyzed on the basis of their phenotypic and molecular characteristics. The phylogenetic analysis based on 16S rRNA and housekeeping genes (recA and atpD) showed that the isolated bacteria related to Sinorhizobium, Neorhizobium, Phyllobacterium, Arthrobacter, Variovorax and Pseudomonas genera. This is the first report of Neorhizobium genus associated with Hedysarum genus. Phenotypically, all strains tolerate the elevated temperature of 40 °C, and salt stress at a concentration of 2%. In addition, the isolates failed to induce nodulation on their original host; and the symbiotic genes could not be amplified, suggesting that these strains are endophytic bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Bacteria Isolated from Post-Partum Infections

    Directory of Open Access Journals (Sweden)

    Nahid Arianpour

    2009-06-01

    Full Text Available Objective: This study was undertaken with an aim to determine bacterial species involved in post partum infections and also their abundance in patients admitted to at Khanevadeh hospital. In this study out of three different kinds of postpartum infections (i.e. genital, breast and urinary tract, only genital infection is considered.Materials and Methods: Post partum infection among 6077 patients (inpatients and re-admitted patients of Khanevadeh hospital from 2003 till 2008 was studied in this descriptive study. Samples were collected from patients for laboratory diagnosis to find out the causative organisms.Results: Follow up of mothers after delivery revealed 7.59% (461 patients had post partum infection, out of which 1.03% (63 patients were re-hospitalized. Infection was more often among younger mothers. Bacteria isolated and identified were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora of the site of infection. Though, some pathogenic bacteria like Staphylococcus aureus, Neisseria gonorrhea, Chlamydia trachomatis,were also the causative agents. The commonest infection was infection at the site of episiotomy. Conclusion: Puerperal infection was detected in of 7.59% mothers. Bacteria isolated were both aerobic and anaerobic cocci and bacilli, majority of which were normal flora. However; some pathogenic bacteria were isolated.

  14. Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

    Science.gov (United States)

    Dunlap, Paul V; Ast, Jennifer C

    2005-02-01

    Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of

  15. Investigation of IR absorption spectra of oral cavity bacteria

    Science.gov (United States)

    Belikov, Andrei V.; Altshuler, Gregory B.; Moroz, Boris T.; Pavlovskaya, Irina V.

    1996-12-01

    The results of comparative investigation for IR and visual absorption spectra of oral cavity bacteria are represented by this paper. There are also shown the main differences in absorption spectra of such pure bacteria cultures as : E- coli, Candida, Staph, Epidermidis, and absorption spectra of bacteria colonies cultured in tooth root canals suspected to harbour several endodontical problems. The results of experimental research targeted to investigate an effect of such combined YAG:Nd and YAG:Cr; Tm; Ho laser parameters like: wavelength, energy density, average power and etc., to oral cavity bacteria deactivation are given finally.

  16. Oh What a Tangled Biofilm Web Bacteria Weave

    Science.gov (United States)

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  17. Toxicity of tetracyclines and tetracycline degradation products to environmentally relevant bacteria, including selected tetracycline-resistant bacteria

    DEFF Research Database (Denmark)

    Halling-Sørensen, B.; Sengeløv, G.; Tjørnelund, J.

    2002-01-01

    Tetracyclines used in veterinary therapy invariably will find their way as parent compound and degradation products to the agricultural field. Major degradation products formed due to the limited stability of parent tetracyclines (tetracycline, chlortetracycline, and oxytetracycline) in aqueous...... at the same concentration level as tetracycline, chlortetracycline, and oxytetracycline on both the sludge and the tetracycline-sensitive soil bacteria. Further, both 5a,6-anhydrotetracychne and 5a,6-anhydrochlortetracycline had potency on tetracycline-resistant bacteria supporting a mode of action different...

  18. Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria.

    Science.gov (United States)

    Beltran-Garcia, Miguel J; White, James F; Prado, Fernanda M; Prieto, Katia R; Yamaguchi, Lydia F; Torres, Monica S; Kato, Massuo J; Medeiros, Marisa H G; Di Mascio, Paolo

    2014-11-06

    Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.

  19. The effects of deuterium-depleted water on bacteria

    International Nuclear Information System (INIS)

    Butnaru, Gallia; Jurca, Elena M.; Titescu, Gh.; Stefanescu, I.

    2000-01-01

    Due to their adaptability the bacteria are ubiquitous, occurring in a large variety of habitats. Most of them are saprotrophs or parasites. Bacteria are agents causing many diseases in animals and humans. The main purpose of this work was to reveal the deuterium-depleted water bactericidal effect. Nonpathogenic Gram-positive (Bacillus subtilis and Bacillus cereus) and pathogenic Gram-negative (Agrobacterium tumefaciens, Erwinia amylovora and Escherichia coli) bacteria were used. The variant deuterium depleted (DDW) eater was compared with distilled water eater one. The diffusometric method was found the proper way of investigation. The bacteria culture was developed in Petri dishes (diam = 70 mm) at a temperature of 25 deg. C. After 24 h, 48 h and 72 h the clear area was measured. The clear area was one in which the bacteria were killed. The surface was determined by the area of the small disc on the filter paper. The statistical data were determined by variance analysis. The results pointed out a large response to DDW presence. The data were classified in: 1. without response when no clear area occurred; - 2. with response when a clear area of under 5 mm 2 occurred; - 3. strong response when the clear area was higher than 10 mm 2 . The Gram-positive and Gram-negative bacteria behaviours were not in correlation with the DDW bactericidal effect. The Bacillus cereus and Escherichia coli were scored as without response and we presume that they were very tolerant. No clear area was induced by DDW. Bacillus subtilis and Erwinia amylovora showed weak response. After 24 h the killed bacteria were extended on the same area, namely, 2.89 mm 2 . Even if the DDW effect seems to be small it was significantly in comparison with the control case (s d = 2.78 mm 2 > 0.1). After 48 h and 72 h the clear surface remained the same. The Agrobacterium tumefaciens' response was very strong. The bacteria were killed on 22.50 mm 2 after 24 h and on 26.95 mm 2 after 48 h, being very

  20. Leucine incorporation by aerobic anoxygenic phototrophic bacteria in the Delaware estuary

    Science.gov (United States)

    Stegman, Monica R; Cottrell, Matthew T; Kirchman, David L

    2014-01-01

    Aerobic anoxygenic phototrophic (AAP) bacteria are well known to be abundant in estuaries, coastal regions and in the open ocean, but little is known about their activity in any aquatic ecosystem. To explore the activity of AAP bacteria in the Delaware estuary and coastal waters, single-cell 3H-leucine incorporation by these bacteria was examined with a new approach that combines infrared epifluorescence microscopy and microautoradiography. The approach was used on samples from the Delaware coast from August through December and on transects through the Delaware estuary in August and November 2011. The percent of active AAP bacteria was up to twofold higher than the percentage of active cells in the rest of the bacterial community in the estuary. Likewise, the silver grain area around active AAP bacteria in microautoradiography preparations was larger than the area around cells in the rest of the bacterial community, indicating higher rates of leucine consumption by AAP bacteria. The cell size of AAP bacteria was 50% bigger than the size of other bacteria, about the same difference on average as measured for activity. The abundance of AAP bacteria was negatively correlated and their activity positively correlated with light availability in the water column, although light did not affect 3H-leucine incorporation in light–dark experiments. Our results suggest that AAP bacteria are bigger and more active than other bacteria, and likely contribute more to organic carbon fluxes than indicated by their abundance. PMID:24824666