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Sample records for bacteria geobacillus stearothermophilus

  1. Biosynthesis of omega-alicyclic fatty acids induced by cyclic precursors and change of membrane fluidity in thermophilic bacteria Geobacillus stearothermophilus and Meiothermus ruber.

    Czech Academy of Sciences Publication Activity Database

    Si?iš?ová, L.; Luhový, R.; Sigler, Karel; ?ezanka, Tomáš

    2011-01-01

    Ro?. 15, ?. 3 (2011), 423-429. ISSN 1431-0651 Institutional research plan: CEZ:AV0Z50200510 Keywords : Thermophilic bacteria * Geobacillus * Meiothermus Subject RIV: EE - Microbiology, Virology Impact factor: 2.941, year: 2011

  2. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    Science.gov (United States)

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  3. DECONTAMINATION ASSESSMENT OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS, AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACTS USING A HYDROGEN PERIOXIDE GAS GENERATOR

    Science.gov (United States)

    Aims: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. Methods and Results: B. anthracis, B. subtilis, and G. Stearothermophilus spores were dried on seven...

  4. Expression and Characterization of Geobacillus stearothermophilus SR74 Recombinant ?-Amylase in Pichia pastoris

    Science.gov (United States)

    Gandhi, Sivasangkary; Salleh, Abu Bakar; Rahman, Raja Noor Zaliha Raja Abd; Chor Leow, Thean; Oslan, Siti Nurbaya

    2015-01-01

    Geobacillus stearothermophilus SR74 is a locally isolated thermophilic bacteria producing thermostable and thermoactive ?-amylase. Increased production and commercialization of thermostable ?-amylase strongly warrant the need of a suitable expression system. In this study, the gene encoding the thermostable ?-amylase in G. stearothermophilus SR74 was amplified, sequenced, and subcloned into P. pastoris GS115 strain under the control of a methanol inducible promoter, alcohol oxidase (AOX). Methanol induced recombinant expression and secretion of the protein resulted in high levels of extracellular amylase production. YPTM medium supplemented with methanol (1% v/v) was the best medium and once optimized, the maximum recombinant ?-amylase SR74 achieved in shake flask was 28.6?U?mL?1 at 120?h after induction. The recombinant 59?kDa ?-amylase SR74 was purified 1.9-fold using affinity chromatography with a product yield of 52.6% and a specific activity of 151.8?U?mg?1. The optimum pH of ?-amylase SR74 was 7.0 and the enzyme was stable between pH 6.0–8.0. The purified enzyme was thermostable and thermoactive, exhibiting maximum activity at 65°C with a half-life (t1/2) of 88?min at 60°C. In conclusion, thermostable ?-amylase SR74 from G. stearothermophilus SR74 would be beneficial for industrial applications, especially in liquefying saccrification.

  5. Isolation of Lipase Gene of the Thermophilic Geobacillus stearothermophilus Strain-5

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    M. Sifour

    2010-01-01

    Full Text Available In earlier study a new thermophilic strain Geobacillus stearothermophilus strain-5 producing thermostable lipase was isolated and identified based on 16S rRNA sequencing. Phylogenetic analysis revealed its closeness to geobacilli especially the thermophilic Geobacillus stearothermophilus with optimal growth and lipolytic enzyme activity at 60°C and pH 7.0. In this study thermostable lipase gene from this bacterium was isolated by PCR using degenerate primers. The DNA fragment coding for lipase gene was cloned in the pCR 4-TOPO plasmid and the ligation products were transformed into Escherichia coli XL1-blue cells. Partial sequencing of the gene was carried out (accession number DQ923401. Analysis by BLAST program showed some sequence similarity to that, of several lipase genes from thermophilic Geobacillus and Bacillus submitted to Genbank.

  6. Evolved ?-Galactosidases from Geobacillus stearothermophilus with Improved Transgalactosylation Yield for Galacto-Oligosaccharide Production? †

    OpenAIRE

    Placier, Gaël; Watzlawick, Hildegard; Rabiller, Claude; Mattes, Ralf

    2009-01-01

    A mutagenesis approach was applied to the ?-galactosidase BgaB from Geobacillus stearothermophilus KVE39 in order to improve its enzymatic transglycosylation of lactose into oligosaccharides. A simple screening strategy, which was based on the reduction of the hydrolysis of a potential transglycosylation product (lactosucrose), provided mutant enzymes possessing improved synthetic properties for the autocondensation product from nitrophenyl-galactoside and galacto-oligosaccharides (GOS) from...

  7. Crystal Structure of the Geobacillus stearothermophilus Carboxylesterase Est55 and Its Activation of Prodrug CPT-11

    OpenAIRE

    Liu, Ping; Ewis, Hosam E.; Tai, Phang C.; Lu, Chung-dar; Weber, Irene T.

    2006-01-01

    Several mammalian carboxylesterases were shown to activate the prodrug irinotecan (CPT-11) to produce SN-38, a topoisomerase inhibitor used in cancer therapy. However, the potential use of bacterial carboxylesterases, which have the advantage of high stability, has not been explored. We present the crystal structure of the carboxyesterase Est55 from Geobacillus stearothermophilus and evaluation of its enzyme activity on CPT-11. Crystal structures were determined at pH 6.2 and 6.8 and resoluti...

  8. Modeling the behavior of Geobacillus stearothermophilus ATCC 12980 throughout its life cycle as vegetative cells or spores using growth boundaries.

    Science.gov (United States)

    Mtimet, Narjes; Trunet, Clément; Mathot, Anne-Gabrielle; Venaille, Laurent; Leguérinel, Ivan; Coroller, Louis; Couvert, Olivier

    2015-06-01

    Geobacillus stearothermophilus is recognized as one of the most prevalent micro-organism responsible for flat sour in the canned food industry. To control these highly resistant spore-forming bacteria, the heat treatment intensity could be associated with detrimental conditions for germination and outgrowth. The purpose of this work was to study successively the impact of temperature and pH on the growth rate of G. stearothermophilus ATCC 12980, its sporulation ability, its heat resistance in response to various sporulation conditions, and its recovery ability after a heat treatment. The phenotypic investigation was carried out at different temperatures and pHs on nutrient agar and the heat resistance was estimated at 115 °C. The greatest spore production and the highest heat resistances were obtained at conditions of temperature and pH allowing maximal growth rate. The current observations also revealed that growth, sporulation and recovery boundaries are close. Models using growth boundaries as main parameters were extended to describe and quantify the effect of temperature and pH throughout the life cycle of G. stearothermophilus as vegetative cells or as spore after a heat treatment and during recovery. PMID:25791003

  9. Molecular Basis of S-layer Glycoprotein Glycan Biosynthesis in Geobacillus stearothermophilus*S?

    OpenAIRE

    Steiner, Kerstin; Novotny, Rene?; Werz, Daniel B.; Zarschler, Kristof; Seeberger, Peter H.; Hofinger, Andreas; Kosma, Paul; Scha?ffer, Christina; Messner, Paul

    2008-01-01

    The Gram-positive bacterium Geobacillus stearothermophilus NRS 2004/3a possesses a cell wall containing an oblique surface layer (S-layer) composed of glycoprotein subunits. O-Glycans with the structure [?2)-?-l-Rhap-(1?3)-?-l-Rhap-(1?2)-?-l-Rhap-(1?]n = 13-18, a2-O-methyl group capping the terminal repeating unit at the nonreducing end and a ?2)-?-l-Rhap-[(1?3)-?-l-Rhap]n = 1-2(1?3)- adaptor are linked via a ?-d-Galp residue to distinct sit...

  10. Structural Analysis of Xylanase from Marine Thermophilic Geobacillus stearothermophilus in Tanjung Api, Poso, Indonesia

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    BUDI SAKSONO

    2010-12-01

    Full Text Available A xylanase gene, xynA, has been cloned from thermophilic strain Geobacillus stearothermophilus, which was isolated from marine Tanjung Api, Indonesia. The polymerase chain reaction product of 1266 bp of xynA gene consisted of 1221 bp open reading frame and encoded 407 amino acids including 30 residues of signal peptide. The sequence exhibited highest identity of 98.7% in the level of amino acid, with an extracellular endo-1,4-?-xylanase from G. stearothermophilus T-6 (E-GSX T-6 of the glycoside hydrolase family 10 (GH10. A comparative study between the local strain G. stearothermophilus (GSX L and E-GSX T-6 on homology of amino acid sequence indicated five differents amino acids in the gene. They were Threonine/Alanine (T/A, Asparagine/Aspartate (N/D, Lysine/Asparagine (K/N, Isoleucine/Methionine (I/M, Serine/Threonine (S/T at the position 220, 227, 228, 233, and 245, respectively. Protein structural analysis of those differences suggested that those amino acids may play role in biochemical properties such as enzyme stability, in particular its thermostability.

  11. Quantitative assessment of the risk of microbial spoilage in foods. Prediction of non-stability at 55 °C caused by Geobacillus stearothermophilus in canned green beans.

    Science.gov (United States)

    Rigaux, Clémence; André, Stéphane; Albert, Isabelle; Carlin, Frédéric

    2014-02-01

    Microbial spoilage of canned foods by thermophilic and highly heat-resistant spore-forming bacteria, such as Geobacillus stearothermophilus, is a persistent problem in the food industry. An incubation test at 55 °C for 7 days, then validation of biological stability, is used as an indicator of compliance with good manufacturing practices. We propose a microbial risk assessment model predicting the percentage of non-stability due to G. stearothermophilus in canned green beans manufactured by a French company. The model accounts for initial microbial contaminations of fresh unprocessed green beans with G. stearothermophilus, cross-contaminations in the processing chain, inactivation processes and probability of survival and growth. The sterilization process is modeled by an equivalent heating time depending on sterilization value F? and on G. stearothermophilus resistance parameter z(T). Following the recommendations of international organizations, second order Monte-Carlo simulations are used, separately propagating uncertainty and variability on parameters. As a result of the model, the mean predicted non-stability rate is of 0.5%, with a 95% uncertainty interval of [0.1%; 1.2%], which is highly similar to data communicated by the French industry. A sensitivity analysis based on Sobol indices and some scenario tests underline the importance of cross-contamination at the blanching step, in addition to inactivation due to the sterilization process. PMID:24334097

  12. Keratinous waste decomposition and peptide production by keratinase from Geobacillus stearothermophilus AD-11.

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    Gegeckas, Audrius; Gudiukait?, Renata; Debski, Janusz; Citavicius, Donaldas

    2015-04-01

    A keratinolytic proteinase was cloned from thermophilic bacterium Geobacillus stearothermophilus AD-11 and was expressed in Escherichia coli BL21(DE3). Recombinant keratinolytic proteinase (RecGEOker) with an estimated molecular weight of 57 kDa was purified and keratinase activity was measured. RecGEOker showed optimal activity at pH 9 and 60 °C. Recombinant keratinolytic proteinase showed the highest substrate specificity toward keratin from wool > collagen > sodium caseinate > gelatin > and BSA in descending order. RecGEOker is applicable for efficient keratin waste biodegradation and can replace conventional non-biological hydrolysis processes. High-value small peptides obtained from enzymatic biodegradation by RecGEOker are suitable for industrial application in white and/or green biotechnology for use as major additives in various products. PMID:25625783

  13. Direct fermentation of potato starch and potato residues to lactic acid by Geobacillus stearothermophilus under non-sterile conditions

    Science.gov (United States)

    Smerilli, Marina; Neureiter, Markus; Wurz, Stefan; Haas, Cornelia; Frühauf, Sabine; Fuchs, Werner

    2015-01-01

    BACKGROUND Lactic acid is an important biorefinery platform chemical. The use of thermophilic amylolytic microorganisms to produce lactic acid by fermentation constitutes an efficient strategy to reduce operating costs, including raw materials and sterilization costs. RESULTS A process for the thermophilic production of lactic acid by Geobacillus stearothermophilus directly from potato starch was characterized and optimized. Geobacillus stearothermophilus DSM 494 was selected out of 12 strains screened for amylolytic activity and the ability to form lactic acid as the major product of the anaerobic metabolism. In total more than 30 batches at 3–l scale were run at 60 °C under non-sterile conditions. The process developed produced 37 g L?1 optically pure (98%) L-lactic acid in 20 h from 50 g L?1 raw potato starch. As co-metabolites smaller amounts (John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25937690

  14. Tryptophan Oxidative Metabolism Catalyzed by Geobacillus Stearothermophilus: A Thermophile Isolated from Kuwait Soil Contaminated with Petroleum Hydrocarbons

    OpenAIRE

    Al-hassan, Jassim M.; Samira Al-Awadi; Sosamma Oommen; Abdulaziz Alkhamis; Mohammad Afzal

    2011-01-01

    Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M p...

  15. Evolved ?-Galactosidases from Geobacillus stearothermophilus with Improved Transgalactosylation Yield for Galacto-Oligosaccharide Production? †

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    Placier, Gaël; Watzlawick, Hildegard; Rabiller, Claude; Mattes, Ralf

    2009-01-01

    A mutagenesis approach was applied to the ?-galactosidase BgaB from Geobacillus stearothermophilus KVE39 in order to improve its enzymatic transglycosylation of lactose into oligosaccharides. A simple screening strategy, which was based on the reduction of the hydrolysis of a potential transglycosylation product (lactosucrose), provided mutant enzymes possessing improved synthetic properties for the autocondensation product from nitrophenyl-galactoside and galacto-oligosaccharides (GOS) from lactose. The effects of the mutations on enzyme activity and kinetics were determined. An change of one arginine to lysine (R109K) increased the oligosaccharide yield compared to that for the wild-type BgaB. Subsequently, saturation mutagenesis at this position demonstrated that valine and tryptophan further increased the transglycosylation performance of BgaB. During the transglycosylation reaction with lactose of the evolved ?-galactosidases, a major trisaccharide was formed. Its structure was characterized as ?-d-galactopyranosyl-(1?3)-?-d-galactopyranosyl-(1?4)-d-glucopyranoside (3?-galactosyl-lactose). At the lactose concentration of 18% (wt/vol), this trisaccharide was obtained in yields of 11.5% (wt/wt) with GP21 (BgaB R109K), 21% with GP637.2 (BgaB R109V), and only 2% with the wild-type BgaB enzyme. GP643.3 (BgaB R109W) was shown to be the most efficient mutant, with a 3?-galactosyl-lactose production of 23%. PMID:19666723

  16. Evolved beta-galactosidases from Geobacillus stearothermophilus with improved transgalactosylation yield for galacto-oligosaccharide production.

    Science.gov (United States)

    Placier, Gaël; Watzlawick, Hildegard; Rabiller, Claude; Mattes, Ralf

    2009-10-01

    A mutagenesis approach was applied to the beta-galactosidase BgaB from Geobacillus stearothermophilus KVE39 in order to improve its enzymatic transglycosylation of lactose into oligosaccharides. A simple screening strategy, which was based on the reduction of the hydrolysis of a potential transglycosylation product (lactosucrose), provided mutant enzymes possessing improved synthetic properties for the autocondensation product from nitrophenyl-galactoside and galacto-oligosaccharides (GOS) from lactose. The effects of the mutations on enzyme activity and kinetics were determined. An change of one arginine to lysine (R109K) increased the oligosaccharide yield compared to that for the wild-type BgaB. Subsequently, saturation mutagenesis at this position demonstrated that valine and tryptophan further increased the transglycosylation performance of BgaB. During the transglycosylation reaction with lactose of the evolved beta-galactosidases, a major trisaccharide was formed. Its structure was characterized as beta-D-galactopyranosyl-(1-->3)-beta-D-galactopyranosyl-(1-->4)-D-glucopyranoside (3'-galactosyl-lactose). At the lactose concentration of 18% (wt/vol), this trisaccharide was obtained in yields of 11.5% (wt/wt) with GP21 (BgaB R109K), 21% with GP637.2 (BgaB R109V), and only 2% with the wild-type BgaB enzyme. GP643.3 (BgaB R109W) was shown to be the most efficient mutant, with a 3'-galactosyl-lactose production of 23%. PMID:19666723

  17. The Geobacillus stearothermophilus V iscS Gene, Encoding Cysteine Desulfurase, Confers Resistance to Potassium Tellurite in Escherichia coli K-12

    OpenAIRE

    Tantaleán, Juan C.; Araya, Manuel A.; Saavedra, Claudia P.; Fuentes, Derie E.; Pérez, José M; Calderón, Iván L.; Youderian, Philip; Vásquez, Claudio C

    2003-01-01

    Many eubacteria are resistant to the toxic oxidizing agent potassium tellurite, and tellurite resistance involves diverse biochemical mechanisms. Expression of the iscS gene from Geobacillus stearothermophilus V, which is naturally resistant to tellurite, confers tellurite resistance in Escherichia coli K-12, which is naturally sensitive to tellurite. The G. stearothermophilus iscS gene encodes a cysteine desulfurase. A site-directed mutation in iscS that prevents binding of its pyridoxal pho...

  18. Strain Improvement of Bacillus coagulans and Geobacillus stearothermophilus for Enhanced Thermostable Cellulase Production and the Effect of Different Metal Ions on Cellulase Activity

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    Vikas Sharma

    2012-11-01

    Full Text Available The current study was focused on the strain improvement of Bacillus coagulans and Geobacillus stearothermophilus for thermostable cellulase production with higher enzyme activity. For strain improvement UV radiations, NTG and Sodium azide were used as mutagenic agents.NTG was found to be best mutagenic agent among all in term of highest cellulase activity. Mutant strain C11 exhibited the highest cellulase specific activity at 45 U/mg followed by C15 (39 U/mg in case of B.coagulans while Mutant strain S18 exhibited thehighest cellulase specific activity at 69 U/mg followed by S12 (62 U/mg in case of G. stearothermophilus. Specific activity of cellulase was 92 U/mg in case of B.coagulans C11 and 118 U/mg in case of G. stearothermophilus S18. Ag+, Mg+, Se2+,Ca2+,Co2+,Mn2+,K+, Zn2+ ,Fe3+, Hg2+ and Cu2+ showed positive change in specific activity while Na+, Ni2+ negative change in specific activity of cellulase with respect to specific activity of cellulase in absence of any additive in case of B.coagulans C11 and Ag+, Mg+, Se2+,Co2+,Mn2+ andHg2+ showed positive change in specific activity, Na+, K+ showed no change in specific activity while Ca2+, Zn2+, Ni2+, Fe3+ and Cu2+ showed negative change in specific activity of cellulase with respect to specific activity of cellulase in absence of any additive in case of G. stearothermophilus S18.

  19. Characterization of a Novel Thermostable Carboxylesterase from Geobacillus kaustophilus HTA426 Shows the Existence of a New Carboxylesterase Family?

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    Montoro-garci?a, Silvia; Marti?nez-marti?nez, Irene; Navarro-ferna?ndez, Jose?; Takami, Hideto; Garci?a-carmona, Francisco; Sa?nchez-ferrer, A?lvaro

    2009-01-01

    The gene GK3045 (741 bp) from Geobacillus kaustophilus HTA426 was cloned, sequenced, and overexpressed into Escherichia coli Rosetta (DE3). The deduced protein was a 30-kDa monomeric esterase with high homology to carboxylesterases from Geobacillus thermoleovorans NY (99% identity) and Geobacillus stearothermophilus (97% identity). This protein suffered a proteolytic cut in E. coli, and the problem was overcome by introducing a mutation in the gene (K212R) without affecting the activity. The ...

  20. Influence of temperature and organic load on chemical disinfection of Geobacillus steareothermophilus spores, a surrogate for Bacillus anthracis

    OpenAIRE

    Guan, Jiewen; Chan, Maria; Brooks, Brian W.; Rohonczy, Liz

    2013-01-01

    This study evaluated the influence of temperature and organic load on the effectiveness of domestic bleach (DB), Surface Decontamination Foam (SDF), and Virkon in inactivating Geobacillus stearothermophilus spores, which are a surrogate for Bacillus anthracis spores. The spores were suspended in light or heavy organic preparations and the suspension was applied to stainless steel carrier disks. The dried spore inoculum was covered with the disinfectants and the disks were then incubated at va...

  1. Preconditioning with Cations Increases the Attachment of Anoxybacillus flavithermus and Geobacillus Species to Stainless Steel

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    Somerton, Ben; Flint, Steve; Palmer, Jon; Brooks, John (Irish printmaker, active 1730-1756); Lindsay, Denise

    2013-01-01

    Preconditioning of Anoxybacillus flavithermus E16 and Geobacillus sp. strain F75 with cations prior to attachment often significantly increased (P ? 0.05) the number of viable cells that attached to stainless steel (by up to 1.5 log CFU/cm2) compared with unconditioned bacteria. It is proposed that the transition of A. flavithermus and Geobacillus spp. from milk formulations to stainless steel product contact surfaces in milk powder manufacturing plants is mediated predominantly by bacterial ...

  2. Preconditioning with Cations Increases the Attachment of Anoxybacillus flavithermus and Geobacillus Species to Stainless Steel

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    Flint, Steve; Palmer, Jon; Brooks, John; Lindsay, Denise

    2013-01-01

    Preconditioning of Anoxybacillus flavithermus E16 and Geobacillus sp. strain F75 with cations prior to attachment often significantly increased (P ? 0.05) the number of viable cells that attached to stainless steel (by up to 1.5 log CFU/cm2) compared with unconditioned bacteria. It is proposed that the transition of A. flavithermus and Geobacillus spp. from milk formulations to stainless steel product contact surfaces in milk powder manufacturing plants is mediated predominantly by bacterial physiological factors (e.g., surface-exposed adhesins) rather than the concentrations of cations in milk formulations surrounding bacteria. PMID:23645192

  3. Tracking spore-forming bacteria in food: from natural biodiversity to selection by processes.

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    Postollec, Florence; Mathot, Anne-Gabrielle; Bernard, Muriel; Divanac'h, Marie-Laure; Pavan, Sonia; Sohier, Danièle

    2012-08-01

    Sporeforming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuff. The state of the art of sporeformer prevalence in ingredients and food was investigated using a multiparametric PCR-based tool that enables simultaneous detection and identification of various genera and species mostly encountered in food, i.e., Alicyclobacillus, Anoxybacillus flavithermus, Bacillus, B. cereus group, B. licheniformis, B. pumilus, B. sporothermodurans, B. subtilis, Brevibacillus laterosporus, Clostridium, Geobacillus stearothermophilus, Moorella and Paenibacillus species. In addition, 16S rDNA sequencing was used to extend identification to other possibly present contaminants. A total of 90 food products, with or without visible trace of spoilage were analysed, i.e., 30 egg-based products, 30 milk and dairy products and 30 canned food and ingredients. Results indicated that most samples contained one or several of the targeted genera and species. For all three tested food categories, 30 to 40% of products were contaminated with both Bacillus and Clostridium. The percentage of contaminations associated with Clostridium or Bacillus represented 100% in raw materials, 72% in dehydrated ingredients and 80% in processed foods. In the last two product types, additional thermophilic contaminants were identified (A. flavithermus, Geobacillus spp., Thermoanaerobacterium spp. and Moorella spp.). These results suggest that selection, and therefore the observed (re)-emergence of unexpected sporeforming contaminants in food might be favoured by the use of given food ingredients and food processing technologies. PMID:22795797

  4. PCR detection of thermophilic spore-forming bacteria involved in canned food spoilage.

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    Prevost, S; Andre, S; Remize, F

    2010-12-01

    Thermophilic bacteria that form highly heat-resistant spores constitute an important group of spoilage bacteria of low-acid canned food. A PCR assay was developed in order to rapidly trace these bacteria. Three PCR primer pairs were designed from rRNA gene sequences. These primers were evaluated for the specificity and the sensitivity of detection. Two primer pairs allowed detection at the species level of Geobacillus stearothermophilus and Moorella thermoacetica/thermoautrophica. The other pair allowed group-specific detection of anaerobic thermophilic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, Caldanerobium and Caldanaerobacter. After a single enrichment step, these PCR assays allowed the detection of 28 thermophiles from 34 cans of spoiled low-acid food. In addition, 13 ingredients were screened for the presence of these bacteria. This PCR assay serves as a detection method for strains able to spoil low-acid canned food treated at 55°C. It will lead to better reactivity in the canning industry. Raw materials and ingredients might be qualified not only for quantitative spore contamination, but also for qualitative contamination by highly heat-resistant spores. PMID:20397018

  5. Contamination pathways of spore-forming bacteria in a vegetable cannery.

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    Durand, Loïc; Planchon, Stella; Guinebretiere, Marie-Hélène; André, Stéphane; Carlin, Frédéric; Remize, Fabienne

    2015-06-01

    Spoilage of low-acid canned food during prolonged storage at high temperatures is caused by heat resistant thermophilic spores of strict or facultative bacteria. Here, we performed a bacterial survey over two consecutive years on the processing line of a French company manufacturing canned mixed green peas and carrots. In total, 341 samples were collected, including raw vegetables, green peas and carrots at different steps of processing, cover brine, and process environment samples. Thermophilic and highly-heat-resistant thermophilic spores growing anaerobically were counted. During vegetable preparation, anaerobic spore counts were significantly decreased, and tended to remain unchanged further downstream in the process. Large variation of spore levels in products immediately before the sterilization process could be explained by occasionally high spore levels on surfaces and in debris of vegetable combined with long residence times in conditions suitable for growth and sporulation. Vegetable processing was also associated with an increase in the prevalence of highly-heat-resistant species, probably due to cross-contamination of peas via blanching water. Geobacillus stearothermophilus M13-PCR genotypic profiling on 112 isolates determined 23 profile-types and confirmed process-driven cross-contamination. Taken together, these findings clarify the scheme of contamination pathway by thermophilic spore-forming bacteria in a vegetable cannery. PMID:25755080

  6. Alkane inducible proteins in Geobacillus thermoleovorans B23

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    Kato Tomohisa

    2009-03-01

    Full Text Available Abstract Background Initial step of ?-oxidation is catalyzed by acyl-CoA dehydrogenase in prokaryotes and mitochondria, while acyl-CoA oxidase primarily functions in the peroxisomes of eukaryotes. Oxidase reaction accompanies emission of toxic by-product reactive oxygen molecules including superoxide anion, and superoxide dismutase and catalase activities are essential to detoxify them in the peroxisomes. Although there is an argument about whether primitive life was born and evolved under high temperature conditions, thermophilic archaea apparently share living systems with both bacteria and eukaryotes. We hypothesized that alkane degradation pathways in thermophilic microorganisms could be premature and useful to understand their evolution. Results An extremely thermophilic and alkane degrading Geobacillus thermoleovorans B23 was previously isolated from a deep subsurface oil reservoir in Japan. In the present study, we identified novel membrane proteins (P16, P21 and superoxide dismutase (P24 whose production levels were significantly increased upon alkane degradation. Unlike other bacteria acyl-CoA oxidase and catalase activities were also increased in strain B23 by addition of alkane. Conclusion We first suggested that peroxisomal ?-oxidation system exists in bacteria. This eukaryotic-type alkane degradation pathway in thermophilic bacterial cells might be a vestige of primitive living cell systems that had evolved into eukaryotes.

  7. Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma evokes distinct changes in morphology and integrity of spores.

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    van Bokhorst-van de Veen, Hermien; Xie, Houyu; Esveld, Erik; Abee, Tjakko; Mastwijk, Hennie; Nierop Groot, Masja

    2015-02-01

    Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is still not fully understood. In this study, the biocidal effect by nitrogen CAP was determined for chemical (hypochlorite and hydrogen peroxide), physical (UV) and heat-resistant spores. The three different sporeformers used are Bacillus cereus a food-borne pathogen, and Bacillus atrophaeus and Geobacillus stearothermophilus that are used as biological indicators for validation of chemical sterilization and thermal processes, respectively. The different spores showed variation in their degree of inactivation by applied heat, hypochlorite, hydrogen peroxide, and UV treatments, whereas similar inactivation results were obtained with the different spores treated with nitrogen CAP. G. stearothermophilus spores displayed high resistance to heat, hypochlorite, hydrogen peroxide, while for UV treatment B. atrophaeus spores are most tolerant. Scanning electron microscopy analysis revealed distinct morphological changes for nitrogen CAP-treated B. cereus spores including etching effects and the appearance of rough spore surfaces, whereas morphology of spores treated with heat or disinfectants showed no such changes. Moreover, microscopy analysis revealed CAP-exposed B. cereus spores to turn phase grey conceivably because of water influx indicating damage of the spores, a phenomenon that was not observed for non-treated spores. In addition, data are supplied that exclude UV radiation as determinant of antimicrobial activity of nitrogen CAP. Overall, this study shows that nitrogen CAP treatment has a biocidal effect on selected Bacillus and Geobacillus spores associated with alterations in spore surface morphology and loss of spore integrity. PMID:25481059

  8. Characterization of the Bacillus stearothermophilus BR219 phenol hydroxylase gene.

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    Kim, I C; Oriel, P J

    1995-01-01

    The catabolic genes pheA and pheB, coding for the conversion of phenol to catechol and catechol to 2-hydroxymuconic semialdehyde, respectively, have been cloned from Bacillus stearothermophilus BR219 into Escherichia coli. Following its localization on the 11-kb B. stearothermophilus DNA insert by deletion and expression analysis, the phenol hydroxylase gene pheA was subcloned as a 2-kb HindIII fragment, whose transformant expressed the enzyme after phenol induction and even more strongly aft...

  9. Use of soybean vinasses as a germinant medium for a Geobacillus stearothermophilus ATCC 7953 sterilization biological indicator.

    Science.gov (United States)

    Dlugokenski, Regina E F; Sella, Sandra R B R; Guizelini, Belquis P; Vandenberghe, Luciana P S; Woiciechowski, Adenise L; Soccol, Carlos R; Minozzo, João C

    2011-04-01

    A novel low-cost medium was developed from by-products and wastes from the ethanol agro-industry to replace commercial media in the production of a steam sterilization biological indicator (BI). Various recovery media were developed using soybean or sugarcane molasses and vinasse to prepare a self-contained BI. Media performance was evaluated by viability and heat resistance (D(121 °C) value) according to regulatory standards. A medium produced with a soybean vinasse ratio of 1:70 (1.4%) (w/v) produced the results, with D(121 °C)=2.9±0.5 min and Usk=12.7±2.1 min. The addition of 0.8% (w/v) yeast extract improved the germination of heat-damaged spores. The pH variation from 6.0 to 7.3 resulted in a gradual increase in the D(121 °C) value. The absence of calcium chloride resulted in a decrease in germination, while no significant differences were observed with starch addition. Soybean vinasses may thus be used as the main component of a culture medium to substitute for commercial media in the production of self-contained biological indicators. The use of ethanol production waste in this biotechnological process realized a reliable performance, minimized the environmental impact, and decreased BI production costs while producing a high quality product. PMID:21336685

  10. Preliminary Characterization of the Probiotic Properties of Candida Famata and Geobacillus Thermoleovorans

    Directory of Open Access Journals (Sweden)

    A Bakhrouf

    2011-12-01

    Full Text Available Background and Objective: Probiotics are live microbial feed supplements which beneficially affect the host animal by improving its intestinal microbial balance, producing metabolites which inhibit the colonization or growth of other microorganisms or by competing with them for resources such as nutrients or space. The aim of this study was to investigate the probiotic properties of Candida famata and Geobacillus thermoleovorans.Material and Methods: In this study, yeast and bacterial strains isolated from pure oil waste were identified using Api 50 CHB and Api Candida Systems and their probiotic properties were studied through antimicrobial activity, biofilm production, adherence assay and enzymatic characterization.Results and Conclusion: According to biochemical analyses, these strains corresponded to Geobacillus thermoleovorans and Candida famata. Antagonism assay results showed that the tested strains have an inhibitory effect against tested pathogenic bacteria. The yeast Candida famata was unable to produce biofilm on Congo Red Agar (CRA, while the bacterial strain was a slime producer. Adherence assays to abiotic surfaces revealed that the investigated strains were fairly adhesive to polystyrene with values ranging from 0.18 to 0.34 at 595 nm. The enzymatic characterization revealed that the tested strains expressed enzymes such as phosphatase alkaline, esterase lipase (C8, amylase, lipase, lecitenase and caseinase. The obtained results may allow the isolated strains to be considered as having the potential to be candidate probiotics.

  11. 21 CFR 184.1012 - ?-Amylase enzyme preparation from Bacillus stearothermophilus.

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2009-04-01 true α-Amylase enzyme preparation from Bacillus stearothermophilus...Affirmed as GRAS § 184.1012 ?-Amylase enzyme preparation from Bacillus stearothermophilus. (a) ?-Amylase enzyme preparation is obtained...

  12. Organophosphonate Utilization by the Thermophile Geobacillus caldoxylosilyticus T20

    OpenAIRE

    Obojska, Agnieszka; Ternan, Nigel G; Lejczak, Barbara; Kafarski, Pawel; McMullan, Geoff

    2002-01-01

    A strain of Geobacillus caldoxylosilyticus from central heating system water could utilize a number of organophosphonates as the sole phosphorus source for growth at 60°C. During growth on glyphosate, aminomethylphosphonate release to the medium was observed, and in cell extracts, a glyphosate oxidoreductase-type activity, producing stoichiometric amounts of aminomethylphosphonate and glyoxylate from glyphosate, was detectable.

  13. Thermostable, Raw-Starch-Digesting Amylase from Bacillus stearothermophilus

    OpenAIRE

    Kim, Jaeyoung; Nanmori, Takashi; Shinke, Ryu

    1989-01-01

    An endospore-forming thermophilic bacterium, which produced amylase and was identified as Bacillus stearothermophilus, was isolated from soil. The amylase had an optimum temperature of 70°C and strongly degraded wheat starch granules (93%) and potato starch granules (80%) at 60°C.

  14. PRODUCTION AND CHARACTERIZATION OF AN ALKALOTHERMOSTABLE, ORGANIC SOLVENT TOLERANT AND SURFACTANT TOLERANT ESTERASE PRODUCED BY A THERMOPHILIC BACTERIUM GEOBACILLUS SP. AGP-04, ISOLATED FROM BAKRESHWAR HOT SPRING, INDIA

    Directory of Open Access Journals (Sweden)

    Amit Ghati

    2013-10-01

    Full Text Available A thermophilic bacteria, Geobacillus sp. AGP-04, isolated from Surya Kund hot spring, Bakreshwar, West Bengal, India was studied in terms of capability of tributyrin hydrolysis and characterization of its thermostable esterase activity using p-nitrophenyl butyrate (PNPB as substrate. The extracellular crude preparation was characterized in terms of pH and temperature optima and stability, organic solvent tolerance capacity and stability, substrate specificity, surfactant tolerance capacity, kinetic parameters and activation/inhibition behavior towards some metal ions and chemicals. Tributyrin agar assay exhibited that Geobacillus sp. AGP-04 secretes an extracellular esterase. The Vmax and Km values of the esterase were found to be 5099 U/Land 103.5µM, respectively in the presence of PNPB as substrate. The optimum temperature and pH, for Geobacillus sp. AGP-04 esterase was 60oC and 8.0, respectively. Although the enzyme activity was not significantly altered by incubating crude extract solution at 20-70oC for 1 hour, the enzyme activity was fully lost at 90oC for same incubation period. The pH stability profile showed that original crude esterase activity is stable at a broad range (pH 5.0-10.0. Moreover, the enzyme was highly organic solvent and surfactant tolerant. The effect of some chemical on crude esterase activity indicated that Geobacillus sp. AGP-04 produce an esterase which contains a serine residue in active site and for its activity -SH groups are essential. Besides, enzyme production was highly induced if fermentation medium contain polysaccharides and oil as carbon source.

  15. Culture Conditions for Production of Thermostable Amylase by Bacillus stearothermophilus

    OpenAIRE

    Srivastava, R. A. K.; Baruah, J. N.

    1986-01-01

    Bacillus stearothermophilus grew better on complex and semisynthetic medium than on synthetic medium supplemented with amino acids. Amylase production on the complex medium containing beef extract or corn steep liquor was higher than on semisynthetic medium containing peptone (0.4%). The synthetic medium, however, did not provide a good yield of extracellular amylase. Among the carbohydrates which favored the production of amylase are, in order starch > dextrin > glycogen > cellobiose > malto...

  16. Effect of Essential Oils on Germination and Growth of Some Pathogenic and Spoilage Spore-Forming Bacteria.

    Science.gov (United States)

    Voundi, Stève Olugu; Nyegue, Maximilienne; Lazar, Iuliana; Raducanu, Dumitra; Ndoye, Florentine Foe; Marius, Stamate; Etoa, François-Xavier

    2015-06-01

    The use of essential oils as a food preservative has increased due to their capacity to inhibit vegetative growth of some bacteria. However, only limited data are available on their effect on bacterial spores. The aim of the present study was to evaluate the effect of some essential oils on the growth and germination of three Bacillus species and Geobacillus stearothermophilus. Essential oils were chemically analyzed using gas chromatography and gas chromatography coupled to mass spectrometry. The minimal inhibitory and bactericidal concentrations of vegetative growth and spore germination were assessed using the macrodilution method. Germination inhibitory effect of treated spores with essential oils was evaluated on solid medium, while kinetic growth was followed using spectrophotometry in the presence of essential oils. Essential oil from Drypetes gossweileri mainly composed of benzyl isothiocyanate (86.7%) was the most potent, with minimal inhibitory concentrations ranging from 0.0048 to 0.0097?mg/mL on vegetative cells and 0.001 to 0.002?mg/mL on spore germination. Furthermore, essential oil from D. gossweileri reduced 50% of spore germination after treatment at 1.25?mg/mL, and its combination with other oils improved both bacteriostatic and bactericidal activities with additive or synergistic effects. Concerning the other essential oils, the minimal inhibitory concentration ranged from 5 to 0.63?mg/mL on vegetative growth and from 0.75 to 0.09?mg/mL on the germination of spores. Spectrophotometric evaluation showed an inhibitory effect of essential oils on both germination and outgrowth. From these results, it is concluded that some of the essential oils tested might be a valuable tool for bacteriological control in food industries. Therefore, further research regarding their use as food preservatives should be carried out. PMID:25884442

  17. Structure of the Apo Form of Bacillus stearothermophilus Phosphofructokinase

    OpenAIRE

    Mosser, Rockann; Reddy, Manchi C.M.; Bruning, John B; Sacchettini, James C; Reinhart, Gregory D.

    2012-01-01

    The crystal structure of the unliganded form of Bacillus stearothermophilus phosphofructokinase (BsPFK) was solved using molecular replacement to 2.8 Å resolution (PDB ID code 3U39). The apo BsPFK structure serves as the basis for the interpretation of any structural changes seen in the binary or ternary complexes. When the apo BsPFK structure is compared with the previously published liganded structures of BsPFK, the structural impact that the binding of the ligands produce is revealed. Thi...

  18. ANTIBACTERIAL ACTIVITY OF PAPAYA LEAF EXTRACTS AGAINST PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Adolf Jan Nexson Parhusip

    2011-11-01

    Full Text Available It was reported that the extracts of papaya leaves could inhibit the growth of Rhizopus stolonifer. Antibacterial activity of Carica papaya leaf extracts on pathogenic bacteria was observed in this study. Papaya leaves were extracted by using maceration method and three kinds of solvents: ethanol, ethyl acetate, and hexane. Papaya leaf extracts were tested against Bacillus stearothermophilus, Listeria monocytogenes, Pseudomonas sp., and Escherichia coli by agar diffusion method. The objectives of this study were to determine extract ability against pathogenic bacteria, to observe the influence of pH, NaCl, and heat on extracts ability, and to observe extract ability against B. stearothermophilus spores. The data showed that ethyl acetate extract could inhibit B. stearothermophilus, L. monocytogenes, Pseudomonas sp., and E. coli. The extract activity was influenced by pH, and it was more effective in low pH. The extract activity was influenced by NaCl against B. stearothermophillus and E. coli. However, it was not influenced by NaCl in bioassay against L. monocytogenes and Pseudomonas sp. The extract activity was influenced by heating process against all the bacteria tested. The extracts inhibited B. stearothermophilus spores as well. Papaya leaves are potential natural anti-bacteria, which might be used in certain kinds of food.

  19. Geobacillus zalihae sp. nov., a thermophilic lipolytic bacterium isolated from palm oil mill effluent in Malaysia

    Directory of Open Access Journals (Sweden)

    Salleh Abu

    2007-08-01

    Full Text Available Abstract Background Thermophilic Bacillus strains of phylogenetic Bacillus rRNA group 5 were described as a new genus Geobacillus. Their geographical distribution included oilfields, hay compost, hydrothermal vent or soils. The members from the genus Geobacillus have a growth temperatures ranging from 35 to 78°C and contained iso-branched saturated fatty acids (iso-15:0, iso-16:0 and iso-17:0 as the major fatty acids. The members of Geobacillus have similarity in their 16S rRNA gene sequences (96.5–99.2%. Thermophiles harboring intrinsically stable enzymes are suitable for industrial applications. The quest for intrinsically thermostable lipases from thermophiles is a prominent task due to the laborious processes via genetic modification. Results Twenty-nine putative lipase producers were screened and isolated from palm oil mill effluent in Malaysia. Of these, isolate T1T was chosen for further study as relatively higher lipase activity was detected quantitatively. The crude T1 lipase showed high optimum temperature of 70°C and was also stable up to 60°C without significant loss of crude enzyme activity. Strain T1T was a Gram-positive, rod-shaped, endospore forming bacterium. On the basic of 16S rDNA analysis, strain T1T was shown to belong to the Bacillus rRNA group 5 related to Geobacillus thermoleovorans (DSM 5366T and Geobacillus kaustophilus (DSM 7263T. Chemotaxonomic data of cellular fatty acids supported the affiliation of strain T1T to the genus Geobacillus. The results of physiological and biochemical tests, DNA/DNA hybridization, RiboPrint analysis, the length of lipase gene and protein pattern allowed genotypic and phenotypic differentiation of strain T1T from its validly published closest phylogenetic neighbors. Strain T1T therefore represents a novel species, for which the name Geobacillus zalihae sp. nov. is proposed, with the type strain T1T (=DSM 18318T; NBRC 101842T. Conclusion Strain T1T was able to secrete extracellular thermostable lipase into culture medium. The strain T1T was identified as Geobacillus zalihae T1T as it differs from its type strains Geobacillus kaustophilus (DSM 7263T and Geobacillus thermoleovorans (DSM 5366T on some physiological studies, cellular fatty acids composition, RiboPrint analysis, length of lipase gene and protein profile.

  20. Enzymatic and cryoreduction EPR studies of the hydroxylation of methylated N(?)-hydroxy-L-arginine analogues by nitric oxide synthase from Geobacillus stearothermophilus.

    Science.gov (United States)

    Davydov, Roman; Labby, Kristin Jansen; Chobot, Sarah E; Lukoyanov, Dmitriy A; Crane, Brian R; Silverman, Richard B; Hoffman, Brian M

    2014-10-21

    Nitric oxide synthase (NOS) catalyzes the conversion of L-arginine to L-citrulline and NO in a two-step process involving the intermediate N(?)-hydroxy-L-arginine (NHA). It was shown that Cpd I is the oxygenating species for L-arginine; the hydroperoxo ferric intermediate is the reactive intermediate with NHA. Methylation of the N(?)-OH and N(?)-H of NHA significantly inhibits the conversion of NHA into NO and L-citrulline by mammalian NOS. Kinetic studies now show that N(?)-methylation of NHA has a qualitatively similar effect on H?O?-dependent catalysis by bacterial gsNOS. To elucidate the effect of methylating N(?)-hydroxy L-arginine on the properties and reactivity of the one-electron-reduced oxy-heme center of NOS, we have applied cryoreduction/annealing/EPR/ENDOR techniques. Measurements of solvent kinetic isotope effects during 160 K cryoannealing cryoreduced oxy-gsNOS/NHA confirm the hydroperoxo ferric intermediate as the catalytically active species of step two. Product analysis for cryoreduced samples with methylated NHA's, NHMA, NMOA, and NMMA, annealed to 273 K, show a correlation of yields of L-citrulline with the intensity of the g 2.26 EPR signal of the peroxo ferric species trapped at 77 K, which converts to the reactive hydroperoxo ferric state. There is also a correlation between the yield of L-citrulline in these experiments and k(obs) for the H?O?-dependent conversion of the substrates by gsNOS. Correspondingly, no detectable amount of cyanoornithine, formed when Cpd I is the reactive species, was found in the samples. Methylation of the NHA guanidinium N(?)-OH and N(?)-H inhibits the second NO-producing reaction by favoring protonation of the ferric-peroxo to form unreactive conformers of the ferric-hydroperoxo state. It is suggested that this is caused by modification of the distal-pocket hydrogen-bonding network of oxy gsNOS and introduction of an ordered water molecule that facilitates delivery of the proton(s) to the one-electron-reduced oxy-heme moiety. These results illustrate how variations in the properties of the substrate can modulate the reactivity of a monooxygenase. PMID:25251261

  1. Structure of the apo form of Bacillus stearothermophilus phosphofructokinase.

    Science.gov (United States)

    Mosser, Rockann; Reddy, Manchi C M; Bruning, John B; Sacchettini, James C; Reinhart, Gregory D

    2012-01-24

    The crystal structure of the unliganded form of Bacillus stearothermophilus phosphofructokinase (BsPFK) was determined using molecular replacement to 2.8 Å resolution (Protein Data Bank entry 3U39 ). The apo BsPFK structure serves as the basis for the interpretation of any structural changes seen in the binary or ternary complexes. When the apo BsPFK structure is compared with the previously published liganded structures of BsPFK, the structural impact that the binding of the ligands produces is revealed. This comparison shows that the apo form of BsPFK resembles the substrate-bound form of BsPFK, a finding that differs from previous predictions. PMID:22212099

  2. Isolation and characterization of a potential paraffin-wax degrading thermophilic bacterial strain Geobacillus kaustophilus TERI NSM for application in oil wells with paraffin deposition problems.

    Science.gov (United States)

    Sood, Nitu; Lal, Banwari

    2008-02-01

    Paraffin deposition problems, that have plagued the oil industry, are currently remediated by mechanical and chemical means. However, since these methods are problematic, a microbiological approach has been considered. The bacteria, required for the mitigation of paraffin deposition problems, should be able to survive the high temperatures of oil wells and degrade the paraffins under low oxygen and nutrient conditions while sparing the low carbon chain paraffins. In this study, a thermophilic paraffinic wax degrading bacterial strain was isolated from a soil sample contaminated with paraffinic crude oil. The selected strain, Geobacillus TERI NSM, could degrade 600mg of paraffinic wax as the sole carbon source in 1000ml minimal salts medium in 7d at 55 degrees C. This strain was identified as Geobacillus kaustophilus by fatty acid methyl esters analysis and 16S rRNA full gene sequencing. G. kaustophilus TERI NSM showed 97% degradation of eicosane, 85% degradation of pentacosane and 77% degradation of triacontane in 10d when used as the carbon source. The strain TERI NSM could also degrade the paraffins of crude oil collected from oil wells that had a history of paraffin deposition problems. PMID:17942139

  3. 1H, 13C, and 15N backbone and side chain resonance assignments of thermophilic Geobacillus kaustophilus cyclophilin-A

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Michael; Zhang, Fengli; Isern, Nancy G.; Armstrong, Geoffrey S.; Eisenmesser, Elan Z.

    2014-04-01

    Cyclophilins catalyze the reversible peptidyl-prolyl isomerization of their substrates and are present across all kingdoms of life from humans to bacteria. Although numerous biological roles have now been discovered for cyclophilins, their function was initially ascribed to their chaperone-like activity in protein folding where they catalyze the often rate-limiting step of proline isomerization. This chaperone-like activity may be especially important under extreme conditions where cyclophilins are often over expressed, such as in tumors for human cyclophilins {Lee, 2010 #1167}, but also in organisms that thrive under extreme conditions, such as theromophilic bacteria. Moreover, the reversible nature of the peptidyl-prolyl isomerization reaction catalyzed by cyclophilins has allowed these enzymes to serve as model systems for probing the role of conformational changes during catalytic turnover {Eisenmesser, 2002 #20;Eisenmesser, 2005 #203}. Thus, we present here the resonance assignments of a thermophilic cyclophilin from Geobacillus kaustophilus derived from deep-sea sediment {Takami, 2004 #1384}. This thermophilic cyclophilin may now be studied at a variety of temperatures to provide insight into the comparative structure, dynamics, and catalytic mechanism of cyclophilins.

  4. Material Conformity and Bactericidal Characteristics of High-Density Ozone Disinfection in Vinyl Polysiloxane Impression and PMMA Dentistry Fillings

    OpenAIRE

    Hiroshi Ohkawa; Tetsuya Akitsu

    2014-01-01

    Disinfection was investigated in high-density ozone produced by dielectric barrier discharge under atmospheric pressure. Disinfection was studied on three-dimensional carriers made of hydrophilic vinyl-polysiloxane impression material and granular acrylic resin used for oral surgery. Experimental results indicate disinfection of spore-forming bacteria: Geobacillus stearothermophilus and Bacillus atrophaeus, and selected species of opportunistic pathogens: Aspergillus ni...

  5. Bacillus stearothermophilus contains a plasmid-borne gene for alpha-amylase.

    OpenAIRE

    Mielenz, J R

    1983-01-01

    The gene for thermostable alpha-amylase from the thermophilic bacterium Bacillus stearothermophilus has been cloned and expressed in Escherichia coli. Each alpha-amylase-producing colony contained at least a 9.7-kilobase-pair (kb) chimeric plasmid composed of the vector pBR322 and a common 5.4-kb HindIII fragment of DNA. B. stearothermophilus contains four plasmids with sizes from 12 kb to over 108 kb. Restriction endonuclease analysis of these naturally occurring plasmids showed they also co...

  6. Effects of gamma- and UV-radiation on DNA synthesis in permeable cells of Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    It was shown that the most of the DNA synthesis is repaired in permeable cells of Bacillus stearothermophilus not affected by injurious agents. ?-irradiation stimulates the reparative synthesis and degradation of DNA whereas UV-radiation decreases the activity of these processes. The reason for such an unusual response of thermophiles to irradiation lies perhaps in high temperatures at which the cells exist

  7. Isolation of phenol-degrading Bacillus stearothermophilus and partial characterization of the phenol hydroxylase.

    OpenAIRE

    Gurujeyalakshmi, G.; Oriel, P.

    1989-01-01

    Bacillus stearothermophilus BR219, isolated from river sediment, degraded phenol at levels to 15 mM at a rate of 0.85 mumol/h (4 x 10(6) cells). The solubilized phenol hydroxylase was NADH dependent, exhibited a 55 degrees C temperature optimum for activity, and was not inhibited by 0.5 mM phenol.

  8. Cloning and expression of a pathway for benzene and toluene from Bacillus stearothermophilus.

    Science.gov (United States)

    Natarajan, M R; Lu, Z; Oriel, P

    1994-06-01

    Bacillus stearothermophilus strain BR325 demonstrating broad aromatic substrate capability was isolated from petroleum-contaminated soil. The chromosomally-located aromatic pathway from this isolate was cloned into Escherichia coli as a 32 kb insert in cosmid pHC79, conferring growth on benzene, phenol, and toluene as sole carbon sources. PMID:7765116

  9. Solution structure of the HU protein from Bacillus stearothermophilus.

    Science.gov (United States)

    Vis, H; Mariani, M; Vorgias, C E; Wilson, K S; Kaptein, R; Boelens, R

    1995-12-01

    The histone-like protein HU from Bacillus stearothermophilus is a dimer with a molecular mass of 19.5 kDa that is capable of bending DNA. An X-ray structure has been determined, but no structure could be established for a large part of the supposed DNA-binding beta-arms. Using distance and dihedral constraints derived from triple-resonance NMR data of a 13C/15N doubly-labelled HU protein 49 distance geometry structures were calculated, which were refined by means of restrained Molecular Dynamics. From this set a total of 25 refined structures were selected having low constraint energy and few constraint violations. The ensemble of 25 structures display a root-mea-square co-ordinate deviation of 0.36 A with respect to the average structure, calculated over the backbone heavy atoms of residues 2 to 54 and 75 to 90 (and residues 2' to 54' and 75' to 90' of the second monomer). The structure of the core is very similar to that observed in the X-ray structure, with a pairwise r.m.s.d. of 1.06 A. The structure of the beta-hairpin arm contains a double flip-over at the prolines in the two strands of the beta-arm. Strong 15N-NH heteronuclear nuclear Overhauser effects indicate that the beta-arm and especially the tip is flexible. This explains the disorder observed in the solution and X-ray structures of the beta-arm, in respect of the core of the protein. Overlayed onto itself the beta-arm is better defined, with an r.m.s.d. of 1.0 A calculated over the backbone heavy atoms of residues 54 to 59 and 69 to 74. The tip of the arm adopts a well-defined 4:6 beta-hairpin conformation similar to the iron co-ordinating beta-arms of rubredoxin. PMID:7500343

  10. Draft Genome Sequence of Lignocellulose-Degrading Thermophilic Bacterium Geobacillus sp. Strain WSUCF1.

    Science.gov (United States)

    Bhalla, Aditya; Kainth, Amoldeep Singh; Sani, Rajesh K

    2013-01-01

    Geobacillus sp. strain WSUCF1 is a thermophilic spore-forming member of the phylum Firmicutes, isolated from a soil sample collected from the compost facility. We report the draft genome sequence of this isolate with an estimated genome size of 3.4 Mb. The genome sequence of this isolate revealed several genes encoding glycoside hydrolases, making it a potential candidate for plant biomass degradation. PMID:23950119

  11. Draft Genome Sequence of Lignocellulose-Degrading Thermophilic Bacterium Geobacillus sp. Strain WSUCF1

    OpenAIRE

    Bhalla, Aditya; Kainth, Amoldeep Singh; Sani, Rajesh K.

    2013-01-01

    Geobacillus sp. strain WSUCF1 is a thermophilic spore-forming member of the phylum Firmicutes, isolated from a soil sample collected from the compost facility. We report the draft genome sequence of this isolate with an estimated genome size of 3.4 Mb. The genome sequence of this isolate revealed several genes encoding glycoside hydrolases, making it a potential candidate for plant biomass degradation.

  12. Mechanism of L-glutamate transport in membrane vesicles from Bacillus stearothermophilus.

    OpenAIRE

    de Vrij, W; Bulthuis, R A; van Iwaarden, P R; Konings, W. N.

    1989-01-01

    In the presence of electrochemical energy, several branched-chain neutral and acidic amino acids were found to accumulate in membrane vesicles of Bacillus stearothermophilus. The membrane vesicles contained a stereo-specific transport system for the acidic amino acids L-glutamate and L-aspartate, which could not translocate their respective amines, L-glutamine and L-asparagine. The transport system was thermostable (Ti = 70 degrees C) and showed highest activities at elevated temperatures (60...

  13. Gene Cloning, DNA Sequencing, and Expression of Thermostable ?-Mannanase from Bacillus stearothermophilus

    OpenAIRE

    Ethier, Nathalie; Talbot, Guylaine; Sygusch, Jurgen

    1998-01-01

    A DNA genomic library constructed from Bacillus stearothermophilus, a gram-positive, facultative thermophilic aerobe that secretes a thermostable ?-mannanase, was screened for mannan hydrolytic activity. Recombinant ?-mannanase activity was detected on the basis of the clearing of halos around Escherichia coli colonies grown on a dye-labelled substrate, Remazol brilliant blue-locust bean gum. The nucleotide sequence of the mannanase gene, manF, corresponded to an open reading frame of 2,085...

  14. Lipid composition and dynamics of cell membranes of Bacillus stearothermophilus adapted to amiodarone

    OpenAIRE

    Rosa, Sónia M. L. J.; Antunes-Madeira, Maria do Carmo; Manuel J. Matos; Jurado, Amália S.; Madeira, Vítor M. C.

    2000-01-01

    Bacillus stearothermophilus, a useful model to evaluate membrane interactions of lipophilic drugs, adapts to the presence of amiodarone in the growth medium. Drug concentrations in the range of 1-2 [mu]M depress growth and 3 [mu]M completely suppresses growth. Adaptation to the presence of amiodarone is reflected in lipid composition changes either in the phospholipid classes or in the acyl chain moieties. Significant changes are observed at 2 [mu]M and expressed by a decrease of phosphatidyl...

  15. Structure based protein engineering of Bacillus stearothermophilus ?-amylase: toward a new substrate specificity

    International Nuclear Information System (INIS)

    Full text. Structural similarity is observed in all members of ?-amylase family but different products are generated during hydrolysis of starch due to different affinities for intermediate dextrins. In order to understand the structural determinants for this property and to introduce different specificity to ?-amylase of Bacillus stearothermophilus we intend to solve the three dimensional structure by X-ray crystallography of the native protein by using synchrotron radiation at Brazilian National Synchrotron Light Laboratory (LNLS). Protein was over expressed in E. coli, purified and crystallization experiments were carried out by using sparse matrix Crystal Screen and Crystal Screen II from Hampton Research (Laguna Hills, CA, USA). Several condition have produced crystals with some defined characteristic: MDP seems to be important to the crystallization: the preferential pH is around 7.5 with organic buffer (HEPES); organic solvent as 2-propanol seems to be also important for the crystallization. On those condition crystals appeared as cluster of needles or small crystals with high number of nucleation. New conditions are being prepared to improve the site and quality of crystals. Data collection of native of Bacillus stearothermophilus ?-amylase will e done at Protein Crystallography Station at LNLS. Crystal structure of mutated ?-amylase bu site direct mutagenesis of residues suggested by the native crystal structure will be obtained. Co-crystallization of Bacbe obtained. Co-crystallization of Bacillus stearothermophilus ?-amylase and oligosaccharide will be carried out to identify residues involved in the binding site to plan new mutation. In another series of mutation the putative binding site residues, once identified, will be mutated to residues observed in TAKA amylase to confer different specificity to ?-amylase. Based on the available TAKA amylase structure, in the primary sequence homology and in the three dimensional model of Bacillus stearothermophilus ?-amylase (using Bacillus licheniformis crystal structure as initial model) it seems that Bacillus stearothermophilus ?-amylase binding site is more complex with and insertion of 40 residues. Therefore the three dimensional structure is crucial to understand the specificity of the substrate of this enzyme which will be used to drive the design of mutation to introduce new properties for industrial purpose. (author)

  16. Highly Thermostable Xylanase Production from A Thermophilic Geobacillus sp. Strain WSUCF1 Utilizing Lignocellulosic Biomass.

    Science.gov (United States)

    Bhalla, Aditya; Bischoff, Kenneth M; Sani, Rajesh Kumar

    2015-01-01

    Efficient enzymatic hydrolysis of lignocellulose to fermentable sugars requires a complete repertoire of biomass deconstruction enzymes. Hemicellulases play an important role in hydrolyzing hemicellulose component of lignocellulose to xylooligosaccharides and xylose. Thermostable xylanases have been a focus of attention as industrially important enzymes due to their long shelf life at high temperatures. Geobacillus sp. strain WSUCF1 produced thermostable xylanase activity (crude xylanase cocktail) when grown on xylan or various inexpensive untreated and pretreated lignocellulosic biomasses such as prairie cord grass and corn stover. The optimum pH and temperature for the crude xylanase cocktail were 6.5 and 70°C, respectively. The WSUCF1 crude xylanase was found to be highly thermostable with half-lives of 18 and 12?days at 60 and 70°C, respectively. At 70°C, rates of xylan hydrolysis were also found to be better with the WSUCF1 secretome than those with commercial enzymes, i.e., for WSUCF1 crude xylanase, Cellic-HTec2, and AccelleraseXY, the percent xylan conversions were 68.9, 49.4, and 28.92, respectively. To the best of our knowledge, WSUCF1 crude xylanase cocktail is among the most thermostable xylanases produced by thermophilic Geobacillus spp. and other thermophilic microbes (optimum growth temperature ?70°C). High thermostability, activity over wide range of temperatures, and better xylan hydrolysis than commercial enzymes make WSUCF1 crude xylanase suitable for thermophilic lignocellulose bioconversion processes. PMID:26137456

  17. Cloning, expression, and isolation of the mannitol transport protein from the thermophilic bacterium Bacillus stearothermophilus.

    Science.gov (United States)

    Henstra, S A; Tolner, B; ten Hoeve Duurkens, R H; Konings, W N; Robillard, G T

    1996-01-01

    A mannitol phosphotransferase system (PTS) was identified in Bacillus stearothermophilus by in vitro complementation with Escherichia coli EI, HPr, and IIA(Mtl). Degenerate primers based on regions of high amino acid similarity in the E. coli and Staphylococcus carnosus EII(Mt1) were used to develop a digoxigenin-labeled probe by PCR. Using this probe, we isolated three overlapping DNA fragments totaling 7.2 kb which contain the genes mtlA, mtlR, mtlF, and mtlD, encoding the mannitol IICB,a regulator, IIA, and a mannitol-1-phosphate dehydrogenase, respectively. The mtl4 gene consists of 1,413 bp coding for a 471-amino-acid protein with a calculated mass of 50.1 kDa. The amino acid sequence shows high similarity with the sequence of IICB(Mtl) of S. carnosus and the IICB part of the IICBA(Mtl)s of E. coli and B. subtilis. The enzyme could be functionally expressed in E. coli by placing it behind the strong tac promoter. The rate of thermal inactivation at 60 degrees C of B. stearothermophilus HCB(Mt1) expressed in E. coli was two times lower than that of E. coli IICB(Mtl). IICB(Mtl) in B. stearothermophilus is maximally active at 85 degrees C and thus very thermostable. The enzyme was purified on Ni-nitrilotriacetic acid resin to greater than 95% purity after six histidines were fused to the C-terminal part of the transporter. PMID:8824601

  18. Cloning, expression, and isolation of the mannitol transport protein from the thermophilic bacterium Bacillus stearothermophilus.

    Science.gov (United States)

    Henstra, S A; Tolner, B; ten Hoeve Duurkens, R H; Konings, W N; Robillard, G T

    1996-10-01

    A mannitol phosphotransferase system (PTS) was identified in Bacillus stearothermophilus by in vitro complementation with Escherichia coli EI, HPr, and IIA(Mtl). Degenerate primers based on regions of high amino acid similarity in the E. coli and Staphylococcus carnosus EII(Mt1) were used to develop a digoxigenin-labeled probe by PCR. Using this probe, we isolated three overlapping DNA fragments totaling 7.2 kb which contain the genes mtlA, mtlR, mtlF, and mtlD, encoding the mannitol IICB,a regulator, IIA, and a mannitol-1-phosphate dehydrogenase, respectively. The mtl4 gene consists of 1,413 bp coding for a 471-amino-acid protein with a calculated mass of 50.1 kDa. The amino acid sequence shows high similarity with the sequence of IICB(Mtl) of S. carnosus and the IICB part of the IICBA(Mtl)s of E. coli and B. subtilis. The enzyme could be functionally expressed in E. coli by placing it behind the strong tac promoter. The rate of thermal inactivation at 60 degrees C of B. stearothermophilus HCB(Mt1) expressed in E. coli was two times lower than that of E. coli IICB(Mtl). IICB(Mtl) in B. stearothermophilus is maximally active at 85 degrees C and thus very thermostable. The enzyme was purified on Ni-nitrilotriacetic acid resin to greater than 95% purity after six histidines were fused to the C-terminal part of the transporter. PMID:8824601

  19. Cloning, expression, and isolation of the mannitol transport protein from the thermophilic bacterium Bacillus stearothermophilus.

    OpenAIRE

    Henstra, S A; Tolner, B.; ten Hoeve Duurkens, R H; Konings, W.N.; Robillard, G. T.

    1996-01-01

    A mannitol phosphotransferase system (PTS) was identified in Bacillus stearothermophilus by in vitro complementation with Escherichia coli EI, HPr, and IIA(Mtl). Degenerate primers based on regions of high amino acid similarity in the E. coli and Staphylococcus carnosus EII(Mt1) were used to develop a digoxigenin-labeled probe by PCR. Using this probe, we isolated three overlapping DNA fragments totaling 7.2 kb which contain the genes mtlA, mtlR, mtlF, and mtlD, encoding the mannitol IICB,a r...

  20. Cloning and Characterization of the str Operon and Elongation Factor Tu Expression in Bacillus stearothermophilus

    OpenAIRE

    Krásný, Libor; Vacík, Tomáš; Fu?ík, Vladimír; Jonák, Ji?í

    2000-01-01

    The complete primary structure of the str operon of Bacillus stearothermophilus was determined. It was established that the operon is a five-gene transcriptional unit: 5?-ybxF (unknown function; homology to eukaryotic ribosomal protein L30)-rpsL (S12)-rpsG (S7)-fus (elongation factor G [EF-G])-tuf (elongation factor Tu [EF-Tu])-3?. The main operon promoter (strp) was mapped upstream of ybxF, and its strength was compared with the strength of the tuf-specific promoter (tufp) located in the...

  1. Effect of ionization and nisin on the Bacillus strains and Salmonella Enteritidis inoculated Stearothermophilus

    International Nuclear Information System (INIS)

    The antimicrobial effect of nisin (at 1000UI/g), and irradiation (at 1, 3 and 5kGy), against the growth of Salmonella enteritidis (106 ufc/ml) and Bacillus Stearothermophilus (106 ufc/ml), inoculated in turkey salami, was studied during storage at 4 degree for 21 days. Treatment of turkey salami with nisin at 1000UI/g did not show any antimicrobial activity against S. Enteritidis with 6.7 pour cent and 0.8 pour cent of reduction after 0 and 21 days of storage respectively, and seems to be insufficient to inhibit B. Stearothermophilus with 23 pour cent and 21 pour cent of reduction after 0 and 21 days of storage respectively. Antimicrobial activities of irradiation were better and proportional to irradiation doses; it shows a reduction of 27 pour cent, 55 pour cent and 67 pour cent by D1, D2 and D3 respectively. The combination of nisin with irradiation at 5kGy showed stronger antimicrobial activities than those obtained by its combination with the first and the second irradiation dose.

  2. Crystal structure of the single-stranded RNA binding protein HutP from Geobacillus thermodenitrificans.

    Science.gov (United States)

    Thiruselvam, Viswanathan; Sivaraman, Padavattan; Kumarevel, Thirumananseri; Ponnuswamy, Mondikalipudur Nanjappagounder

    2014-04-18

    RNA binding proteins control gene expression by the attenuation/antitermination mechanism. HutP is an RNA binding antitermination protein. It regulates the expression of hut operon when it binds with RNA by modulating the secondary structure of single-stranded hut mRNA. HutP necessitates the presence of l-histidine and divalent metal ion to bind with RNA. Herein, we report the crystal structures of ternary complex (HutP-l-histidine-Mg(2+)) and EDTA (0.5 M) treated ternary complex (HutP-l-histidine-Mg(2+)), solved at 1.9 Å and 2.5 Å resolutions, respectively, from Geobacillus thermodenitrificans. The addition of 0.5 M EDTA does not affect the overall metal-ion mediated ternary complex structure and however, the metal ions at the non-specific binding sites are chelated, as evidenced from the results of structural features. PMID:24650662

  3. Determination of thermobacteriological parameters and size of Bacillus stearothermophilus ATCC 7953 spores / Determinação dos parâmetros de destruição térmica e dimensões de esporos de Bacillus stearothermophilus ATCC 7953

    Scientific Electronic Library Online (English)

    Marcos, Fraiha; Antonio Carlos de Oliveira, Ferraz; João Domingos, Biagi.

    1041-10-01

    Full Text Available Este experimento objetivou determinar os parâmetros de destruição térmica de esporos de Bacillus stearothermophilus ATCC 7953 e a estimativa de suas dimensões. Os esporos foram suspensos em solução salina e em mistura de grãos de milho e soja moídos, distribuídos em tubos TDT, e submetidos ao calor [...] por tempo variável, seguido de incubação e contagem direta. Determinou-se o valor D (tempo necessário para redução da viabilidade do micro-organismo em 1 ciclo logarítmico sob determinada temperatura) e o valor z (intervalo de temperatura que ocasiona variação de 10 vezes no valor D). Os esporos suspensos em solução salina foram observados em microscópio eletrônico de varredura, para estimativa das dimensões. Os valores de D121,1 ºC e z para os esporos suspensos em solução salina foram 8,8 minutos e 12,8 ºC, respectivamente. Para aqueles suspensos em mistura milho e soja, D121,1 ºC e z foram 14,2 minutos e 23,7 ºC, respectivamente. As micrografias indicaram que os esporos apresentam-se como bastonetes, homogêneos em forma e dimensão, com comprimento e diâmetro estimados em 2 e 1 µm, respectivamente. Os resultados confirmam a elevada resistência térmica do esporo e indicam que este é um bom indicador biológico para avaliação do processo de extrusão como esterilizante de alimentos. Abstract in english In order to determine thermobacteriological parameters for B. stearothermophilus spores, they were diluted in a saline solution medium and in ground corn-soybean mix, distributed in TDT tube, and submitted to heat for a specific period of time. The D value (time to reduce 1 log cycle of microbial co [...] unt under a certain temperature) and z value (variation of temperature to cause 10-fold change in D value) were estimated. To estimate their dimensions, the spores were visualized by using a scanning electron microscope. D121.1 ºC and z values for these spores, as determined in the saline solution, were 8.8 minutes and 12.8 ºC, respectively. D121,1 ºC and z values determined in the corn-soy mix were 14.2 minutes and 23.7 ºC, respectively. The micrographs indicated that the spores have homogeneous shape and size, with length and diameter of 2 and 1 µm, respectively. These results confirm that the spore is highly thermal-resistant, and it is a good biological indicator to evaluate the extrusion process as a feed sterilizer.

  4. Determination of thermobacteriological parameters and size of Bacillus stearothermophilus ATCC 7953 spores Determinação dos parâmetros de destruição térmica e dimensões de esporos de Bacillus stearothermophilus ATCC 7953

    Directory of Open Access Journals (Sweden)

    Marcos Fraiha

    2010-12-01

    Full Text Available In order to determine thermobacteriological parameters for B. stearothermophilus spores, they were diluted in a saline solution medium and in ground corn-soybean mix, distributed in TDT tube, and submitted to heat for a specific period of time. The D value (time to reduce 1 log cycle of microbial count under a certain temperature and z value (variation of temperature to cause 10-fold change in D value were estimated. To estimate their dimensions, the spores were visualized by using a scanning electron microscope. D121.1 ºC and z values for these spores, as determined in the saline solution, were 8.8 minutes and 12.8 ºC, respectively. D121,1 ºC and z values determined in the corn-soy mix were 14.2 minutes and 23.7 ºC, respectively. The micrographs indicated that the spores have homogeneous shape and size, with length and diameter of 2 and 1 µm, respectively. These results confirm that the spore is highly thermal-resistant, and it is a good biological indicator to evaluate the extrusion process as a feed sterilizer.Este experimento objetivou determinar os parâmetros de destruição térmica de esporos de Bacillus stearothermophilus ATCC 7953 e a estimativa de suas dimensões. Os esporos foram suspensos em solução salina e em mistura de grãos de milho e soja moídos, distribuídos em tubos TDT, e submetidos ao calor por tempo variável, seguido de incubação e contagem direta. Determinou-se o valor D (tempo necessário para redução da viabilidade do micro-organismo em 1 ciclo logarítmico sob determinada temperatura e o valor z (intervalo de temperatura que ocasiona variação de 10 vezes no valor D. Os esporos suspensos em solução salina foram observados em microscópio eletrônico de varredura, para estimativa das dimensões. Os valores de D121,1 ºC e z para os esporos suspensos em solução salina foram 8,8 minutos e 12,8 ºC, respectivamente. Para aqueles suspensos em mistura milho e soja, D121,1 ºC e z foram 14,2 minutos e 23,7 ºC, respectivamente. As micrografias indicaram que os esporos apresentam-se como bastonetes, homogêneos em forma e dimensão, com comprimento e diâmetro estimados em 2 e 1 µm, respectivamente. Os resultados confirmam a elevada resistência térmica do esporo e indicam que este é um bom indicador biológico para avaliação do processo de extrusão como esterilizante de alimentos.

  5. Use of a Mixture of Surrogates for Infectious Bioagents in a Standard Approach to Assessing Disinfection of Environmental Surfaces ?

    OpenAIRE

    Sabbah, Safaa; Springthorpe, Susan; Sattar, Syed A.

    2010-01-01

    We used a mixture of surrogates (Acinetobacter baumannii, Mycobacterium terrae, hepatitis A virus, and spores of Geobacillus stearothermophilus) for bioagents in a standardized approach to test environmental surface disinfectants. Each carrier containing 10 ?l of mixture received 50 ?l of a test chemical or saline at 22 ± 2°C. Disinfectant efficacy criteria were ?6 log10 reduction for the bacteria and the spores and ?3 log10 reduction for the virus. Peracetic acid (1,000 ppm) was effective in...

  6. Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain

    OpenAIRE

    Xiao Zijun; Wang Xiangming; Huang Yunling; Huo Fangfang; Zhu Xiankun; Xi Lijun; Lu Jian R

    2012-01-01

    Abstract Background Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination. Results This work reports the isolation and identification of a novel aerobic Geobacillus strain XT15 capable of producing both of these chemicals under elevated temperatures, thus reducing the risk of bacterial contamination. The optimum growth temperature was found to b...

  7. Experimental fossilisation of the thermophilic Gram-positive bacterium Geobacillus SP7A: a long duration preservation study.

    OpenAIRE

    Orange, Franc?ois; Dupont, Samuel; Le Goff, Olivier; Bienvenu, Nade?ge; Disnar, Jean-robert; Westall, Frances; Le Romancer, Marc

    2014-01-01

    Recent experiments to fossilise microorganisms using silica have shown that the fossilisation process is far more complex than originally thought; microorganisms not only play an active role in silica precipitation but may also remain alive while silica is precipitating on their cell wall. In order to better understand the mechanisms that lead to the preservation of fossilised microbes in recent and ancient rocks, we experimentally silicified a Gram-positive bacterium, Geobacillus SP7A, over ...

  8. Effects of ultrasonic-assisted thermophilic bacteria pretreatment on hydrolysis, acidification, and microbial communities in waste-activated sludge fermentation process.

    Science.gov (United States)

    Yang, Chunxue; Zhou, Aijuan; He, Zhangwei; Jiang, Lei; Guo, Zechong; Wang, Aijie; Liu, Wenzong

    2015-06-01

    A novel pretreatment method combining ultrasonic with thermophilic bacteria (Geobacillus sp. G1) was employed to pretreat waste-activated sludge (WAS) for enhancing the WAS hydrolysis and subsequent volatile fatty acids (VFAs) production. The soluble protein and carbohydrate were mostly released from intracellular ultrasonic-assisted Geobacillus sp. G1 pretreatment, and accumulated to 917?±?70 and 772?±?89 mg COD/L, respectively, which were 2.53- and 2.62-fold higher than that obtained in control test. Excitation emission matrix (EEM) fluorescence spectroscopy revealed the highest fluorescence intensity (FI) of protein-like substances, indicating the synergistic effect of ultrasonic and Geobacillus sp. G1 pretreatments on WAS hydrolysis. The maximum VFAs accumulation was 4437?±?15 mg COD/L obtained in ultrasonic-assisted Geobacillus sp. G1 pretreatment test. High-throughput pyrosequencing analysis investigated that the microbial communities were substantial determined by the pretreatment used. The hydrolysis enhancement was caused by an increase in extracellular enzymes, which was produced by one of dominant species Caloramator sp. The positive effect was well explained to the enhancement of WAS hydrolysis and final VFAs accumulation. PMID:25874413

  9. Thermostable alpha-galactosidase from Bacillus stearothermophilus NUB3621: cloning, sequencing and characterization.

    Science.gov (United States)

    Fridjonsson, O; Watzlawick, H; Gehweiler, A; Mattes, R

    1999-07-01

    An alpha-galactosidase gene from the thermophilic bacterium Bacillus stearothermophilus NUB3621 was cloned, sequenced, expressed in Escherichia coli and the recombinant protein was purified. The Bacillus enzyme, designated AgaN, is similar to alpha-galactosidases of family 36 in the classification of glycosyl hydrolases. The enzyme was estimated to be a tetramer with a molecular mass of subunits 80.3 kDa. The purified AgaN is thermostable and has a temperature optimum of activity at 75 degrees C and a half-life of inactivation of 19 h at 70 degrees C. AgaN displays high affinity for oligomeric substrates such as melibiose and raffinose and is able to hydrolyze raffinose in the presence of 60% sucrose with high efficiency. PMID:10418141

  10. Characteristics of thermostable amylopullulanase of Geobacillus thermoleovorans and its truncated variants.

    Science.gov (United States)

    Nisha, M; Satyanarayana, T

    2015-05-01

    The far-UV CD spectroscopic analysis of the secondary structure in the temperature range between 30 and 90°C revealed a compact and thermally stable structure of C-terminal truncated amylopullulanase of Geobacillus thermoleovorans NP33 (gt-apu?C) with a higher melting temperature [58°C] than G. thermoleovorans NP33 amylopullulanase (gt-apu) [50°C] and the N-terminal truncated amylopullulanase from G. thermoleovorans NP33 (gt-apu?N) [55°C]. A significant decline in random coils in gt-apu?C and gt-apu?N suggested an improvement in conformational stability, and thus, an enhancement in their thermal stability. The improvement in the thermostability of gt-apu?C was corroborated by the thermodynamic parameters for enzyme inactivation. The Trp fluorescence emission (335nm) and the acrylamide quenching constant (22.69M(-1)) of gt-apu?C indicated that the C-terminal truncation increases the conformational stability of the protein with the deeply buried tryptophan residues. The 8-Anilino Naphthalene Sulfonic acid (ANS) fluorescence experiments indicated the unfolding of gt-apu to expose its hydrophobic surface to a greater extent than the gt-apu?C and gt-apu?N. PMID:25748845

  11. Production, Partial Characterization and Cloning of Thermostable ?-amylase of a Thermophile Geobacillus thermoleovorans YN

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Berekaa

    2007-01-01

    Full Text Available In a molecular screening program to select a potent thermostable amylase from a previously isolated thermophiles, a locally isolated, thermophilic lipase-producing Geobacillus thermoleovorans YN (accession number AF385083, was shown to secrete a thermostable ?-amylase constitutively. The optimal enzyme activity was measured at 75°C, where 90% of the activity was retained at 80°C after one hour of incubation. A catabolite repression due to the addition of glucose to the basal salt medium was demonstrated, while 4 folds increase in volumetric production was achieved in LB and starch-supplemented basal salt media and presented in SDS-PAGE and zymogram. A blunt end PCR fragment (2146 bp was amplified from genomic DNA using a designed set of primers and ligated to Bluescript —II KS(+ vector, transformed to E. coli DH5-? competent cells by electroporation and screened on LB-agar plates induced with IPTG. Nucleotide sequencing of selected clone revealed two ORFs, the first was (GTG with a molecular size 1649 nucleotides encoding 549aa residues of a predicted molecular weight 62.592 kD and the second (ATG with a molecular size 1613 nucleotides encoding 537aa residues of a predicted molecular weight 61.04 kD.

  12. Novel thermostable endo-xylanase cloned and expressed from bacterium Geobacillus sp. WSUCF1.

    Science.gov (United States)

    Bhalla, Aditya; Bischoff, Kenneth M; Uppugundla, Nirmal; Balan, Venkatesh; Sani, Rajesh K

    2014-08-01

    A gene encoding a GH10 endo-xylanase from Geobacillus sp. WSUCF1 was cloned and expressed in Escherichia coli. Recombinant endo-xylanase (37kDa) exhibited high specific activity of 461.0U/mg of protein. Endo-xylanase was optimally active on birchwood xylan at 70°C and pH 6.5. The endo-xylanase was found to be highly thermostable at 50 and 60°C, retaining 82% and 50% of its original activity, respectively, after 60h. High xylan conversions (92%) were obtained with oat-spelt xylan hydrolysis. Higher glucan and xylan conversions were obtained on AFEX-treated corn stover with an enzyme cocktail containing WSUCF1 endo-xylanase (71% and 47%) as compared to enzyme cocktail containing commercial fungal endo-xylanase (64% and 41%). High specific activity, active at high pH's, wide substrate specificity, and higher hydrolytic activity on recalcitrant lignocellulose, make this endo-xylanase a suitable candidate for biofuel and bioprocess industries. PMID:24725385

  13. BOGUS BACTERIA...

    Science.gov (United States)

    Mrs. Deaton

    2007-01-24

    Here are some websites to get you started... Just click on the links and start searching! microbe world- bacteria Bacteria Rule Quiz! Bacteria.... Harmful Bacteria Bacteria Museum Bacteria! Microbes- all sorts of info... When you are finished looking at the sites or when you have enough information concerning bacteria, ask Mrs. Deaton for some books that can give you even more DETAIL!!! *Don\\'t forget to keep track of your information on your I-CHARTS... ...

  14. A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    The mechanism of catalysis of the manganese-containing superoxide dismutase from Bacillus stearothermophilus has been shown to involve a 'fast cycle' and a 'slow cycle' (McAdam, M.E., Fox, R.A., Lavelle, F., and Fielden, E.M., Biochem. J.; 165:71 (1977)). Further properties of the enzyme are now considered. Pulse-radiolysis studies, under conditions of low substrate concentration to enzyme concentration (i.e. when the fast cycle predominates), showed that enzyme activity decreases as pH increases (6.5 to 10.2). Activity was unaffected by the addition of H2O2 or NaN3 but slightly decreased by KCN. Both H2O2 and the reducing radical anion CO2sup(-.) caused a decrease in A480 of the native enzyme. The rate of the fast catalytic cycle was independent of temperature (5 to 550C), and as temperature increased the slow catalytic cycle became relatively more important. Arrhenius parameters of the rate constants were estimated. The possible identity of the various forms of the enzyme is considered. (author)

  15. Molecular cloning and characterization of a thermostable lipase from deep-sea thermophile Geobacillus sp. EPT9.

    Science.gov (United States)

    Zhu, Yanbing; Li, Hebin; Ni, Hui; Xiao, Anfeng; Li, Lijun; Cai, Huinong

    2015-02-01

    A gene (1,254 bp) encoding a lipase was identified from a deep-sea hydrothermal field thermophile Geobacillus sp. EPT9. The open reading frame of this gene encoded 417 amino acid residues. The gene was cloned, overexpressed in Escherichia coli, and the target protein was purified to homogeneity. The purified recombinant enzyme presented a molecular mass of 44.8 kDa. When p-nitrophenyl palmitate was used as a substrate, the recombinant lipase was optimally active at 55 °C and pH 8.5. The recombinant enzyme retained 44 % residual activity after incubation at 80 °C for 1 h, which indicated that Geobacillus sp. EPT9 lipase was thermostable. Homology modeling of strain EPT9 lipase was developed with the lipase from Bacillus sp. L2 as a template. The core structure exhibits an ?/?-hydrolase fold and the typical catalytic triad might consist of Ser142, Asp346, and His387. The enzymatic activity of EPT9 lipase was inhibited by addition of phenylmethylsulfonyl fluoride, indicating that it contains serine residue, which plays an important role in the catalytic mechanism. PMID:25388475

  16. Bacteria Museum

    Science.gov (United States)

    Who knew that bacteria had their own virtual museum? Here, visitors will "learn that not all bacteria are harmful, how they are used in industry, that they belong to the oldest living creatures on Earth", and many more interesting facts to discover about the diverse world of bacteria. The "Bacterial Species Files" tab at the top of the page, allows visitors to look up information on 40 different specific bacteria, from Anthrax to Yersinia enterocolitica. The information provided for each bacterium includes photographs, consumer guides, fact sheets, and scientific links. Visitors will find that the "Main Exhibits" tab addresses the basics about bacteria, as well as "Pathogenic Bacteria", "Evolution", "How We Fight Bacteria", and "Food and Water Safety". Visitors will surely enjoy the "Good Bacteria in Food" link found in the Food and Water Safety section, as it explains how some foods benefit from good bacteria, such as Swiss cheese, sausage, sauerkraut, chocolate, and coffee.

  17. Genotyping of Present-Day and Historical Geobacillus Species Isolates from Milk Powders by High-Resolution Melt Analysis of Multiple Variable-Number Tandem-Repeat Loci

    OpenAIRE

    Seale, R. Brent; Dhakal, Rajat; Chauhan, Kanika; Craven, Heather M.; Deeth, Hilton C.; Pillidge, Christopher J.; Powell, Ian B.; Turner, Mark S.

    2012-01-01

    Spores of thermophilic Geobacillus species are a common contaminant of milk powder worldwide due to their ability to form biofilms within processing plants. Genotyping methods can provide information regarding the source and monitoring of contamination. A new genotyping method was developed based on multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) in conjunction with high-resolution melt analysis (MLV-HRMA) and compared to the currently used method, randomized amplified polymor...

  18. Draft Genome Sequence of Geobacillus icigianus Strain G1w1T Isolated from Hot Springs in the Valley of Geysers, Kamchatka (Russian Federation)

    OpenAIRE

    Bryanskaya, Alla V.; Rozanov, Aleksey S.; Logacheva, Maria D.; Kotenko, Anastasia V.; Sergey E. Peltek

    2014-01-01

    The Geobacillus icigianus G1w1T strain was isolated from sludge samples of unnamed vaporing hydrothermal (97°?) outlets situated in a geyser in the Troinoy region (Valley of Geysers, Kronotsky Nature Reserve, Kamchatka, Russian Federation; 54°25?51.40?N, 160°7?41.40?E). The sequenced and annotated genome is 3,457,810 bp and encodes 3,342 genes.

  19. l-Ribose Production from l-Arabinose by Using Purified l-Arabinose Isomerase and Mannose-6-Phosphate Isomerase from Geobacillus thermodenitrificans?

    OpenAIRE

    Yeom, Soo-jin; Kim, Nam-hee; Park, Chang-su; Oh, Deok-kun

    2009-01-01

    Two enzymes, l-arabinose isomerase and mannose-6-phosphate isomerase, from Geobacillus thermodenitrificans produced 118 g/liter l-ribose from 500 g/liter l-arabinose at pH 7.0, 70°C, and 1 mM Co2+ for 3 h, with a conversion yield of 23.6% and a volumetric productivity of 39.3 g liter?1 h?1.

  20. Purification, crystallization and preliminary X-ray analysis of the BseCI DNA methyltransferase from Bacillus stearothermophilus in complex with its cognate DNA

    International Nuclear Information System (INIS)

    The DNA methyltransferase M.BseCI from B. stearothermophilus was crystallized as a complex with its cognate DNA. Crystals belong to space group P6 and diffract to 2.5 Å resolution at a synchrotron source. The DNA methyltransferase M.BseCI from Bacillus stearothermophilus (EC 2.1.1.72), a 579-amino-acid enzyme, methylates the N6 atom of the 3? adenine in the sequence 5?-ATCGAT-3?. M.BseCI was crystallized in complex with its cognate DNA. The crystals were found to belong to the hexagonal space group P6, with unit-cell parameters a = b = 87.0, c = 156.1 Å, ? = 120.0° and one molecule in the asymmetric unit. Two complete data sets were collected at wavelengths of 1.1 and 2.0 Å to 2.5 and 2.8 Å resolution, respectively, using synchrotron radiation at 100 K

  1. [Isolation of endophytic bacteria in potato and test of antagonistic action to bacterial ring rot of potato].

    Science.gov (United States)

    Cui, Lin; Sun, Zhen; Tian, Hong Xian; Wang, Li Qin; Xu, Huei Yuen; Sun, Fu Zai; Yuan, Jun

    2002-12-01

    In this study, two hundred and forty bacterial strains were isolated from inner tissue of potato tubers collected from DaTong, TaiYuan and Inner Mongolia Autonomous regions. On the basis of antagonistic examination in vitro, fifty and five bacteria strains were characterized for antagonistic bacteria to ring rot of potato. It was 22.9 percentage of all bacteria strains. The biggest radius of suppression circle was 13 mm. Nine strains were chosen for their suppression of bacterial ring rot, blackleg and dry rot of potato. These strains were bacteriologically ideatified. Strain 118 was Pseudomonas fluorescens biovar V. Strain 110 was Bacillus pumilus. Strain 085 was Bacillus stearothermophilus. Strain 069 was Erwinia herbicola. Strain 043 was Xanthomomas fragariae. Strain 116 was Curtobacterium. Strains A-10' and T3 were Bacillus. Strain H1-6 was Pseudomonas fluorescens. PMID:15346992

  2. Characterization and multiple applications of a highly thermostable and Ca²?-independent amylopullulanase of the extreme thermophile Geobacillus thermoleovorans.

    Science.gov (United States)

    Nisha, M; Satyanarayana, T

    2014-12-01

    The amylopullulanase of Geobacillus thermoleovorans NP33 (apu105) is Ca(2+)-independent with a molecular mass of 105 kDa and optimum activity at 80 °C and pH 7.0. The apu105 is extremely thermostable with T 1/2 of 7.8 h at 90 °C and hydrolyzes starch, pullulan, and malto-oligosaccharides, but not panose and cyclodextrins. The low K m values of apu105 (starch, pullulan, amylose, and amylopectin) indicates higher affinity of apu105 than others. The action of the enzyme on mixed substrates (starch and pullulan) confirmed the presence of only one active site for cleaving both ?-1,4- and ?-1,6- glycosidic linkages. The raw starches are efficiently hydrolyzed into glucose, maltose, and malto-oligosaccharides. Two-step starch saccharification involving pretreatment with apu105 followed by glucoamylase enhanced glucose yield. The supplementation of whole wheat dough with apu105 markedly enhanced the loaf volume, shelf-life, and the texture of bread. The enzyme is compatible with detergents and useful in desizing of cotton fabrics. PMID:25267353

  3. Bacteria Transformation

    Science.gov (United States)

    2014-09-18

    Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms. For the particular model they work on, they isolate a mammal insulin gene and combine it with a bacteria's gene sequence (plasmid DNA) for production of the protein insulin.

  4. Isolation and Characterization of Thermophilic Cellulase-Producing Bacteria from Empty Fruit Bunches-Palm Oil Mill Effluent Compost

    Directory of Open Access Journals (Sweden)

    Azhari S. Baharuddin

    2010-01-01

    Full Text Available Problems statement: Lack of information on locally isolated cellulase-producing bacterium in thermophilic compost using a mixture of Empty Fruit Bunch (EFB and Palm Oil Mill Effluent (POME as composting materials. Approach: The isolation of microbes from compost heap was conducted at day 7 of composting process where the mixture of composting materials consisted of 45.8% cellulose, 17.1% hemicellulose and 28.3% lignin content. The temperature, pH and moisture content of the composting pile at day 7 treatment were 58.3, 8.1 and 65.5°C, respectively. The morphological analysis of the isolated microbes was conducted using Scanning Electron Microscope (SEM and Gram stain method. The congo red test was conducted in order to detect 1% CMC agar degradation activities. Total genomic DNAs were extracted from approximately 1.0 g of mixed compost and amplified by using PCR primers. The PCR product was sequent to identify the nearest relatives of 16S rRNA genes. The localization of bacteria chromosomes was determined by Fluorescence In Situ Hybridization (FISH analysis. Results: Single isolated bacteria species was successfully isolated from Empty Fruit Bunch (EFB-Palm Oil Mill Effluent (POME compost at thermophilic stage. Restriction fragment length polymorphism profiles of the DNAs coding for the 16S rRNAs with the phylogenetic analysis showed that the isolated bacteria from EFB-POME thermophilic compost gave the highest homology (99% with similarity to Geobacillus pallidus. The strain was spore forming bacteria and able to grow at 60°C with pH 7. Conclusion: Thermophilic bacteria strain, Geobacillus pallidus was successfully isolated from Empty Fruit Bunch (EFB and Palm Oil Mil Effluent (POME compost and characterized.

  5. Production of l-Ribose from l-Ribulose by a Triple-Site Variant of Mannose-6-Phosphate Isomerase from Geobacillus thermodenitrificans

    OpenAIRE

    Lim, Yu-ri; Yeom, Soo-jin; Oh, Deok-kun

    2012-01-01

    A triple-site variant (W17Q N90A L129F) of mannose-6-phosphate isomerase from Geobacillus thermodenitrificans was obtained by combining variants with residue substitutions at different positions after random and site-directed mutagenesis. The specific activity and catalytic efficiency (kcat/Km) for l-ribulose isomerization of this variant were 3.1- and 7.1-fold higher, respectively, than those of the wild-type enzyme at pH 7.0 and 70°C in the presence of 1 mM Co2+. The triple-site variant pr...

  6. Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie J.; Sapra, Rajat; Joyner, Dominique; Hazen, Terry C.; Myers, Samuel; Reichmuth, David; Blanch, Harvey; Keasling, Jay D.

    2009-01-20

    A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and istolerant to high ethanol concentrations (10percent, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-based flux analysis to provide insights into the physiological properties of this extremophile and explore its metabolism for bio-ethanol or other bioprocess applications. Our findings show that glucose metabolism in G. thermoglucosidasius M10EXG proceeds via glycolysis, the pentose phosphate pathway, and the TCA cycle; the Entner?Doudoroff pathway and transhydrogenase activity were not detected. Anaplerotic reactions (including the glyoxylate shunt, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase) were active, but fluxes through those pathways could not be accuratelydetermined using amino acid labeling. When growth conditions were switched from aerobic to micro-aerobic conditions, fluxes (based on a normalized glucose uptake rate of 100 units (g DCW)-1 h-1) through the TCA cycle and oxidative pentose phosphate pathway were reduced from 64+-3 to 25+-2 and from 30+-2 to 19+-2, respectively. The carbon flux under micro-aerobic growth was directed formate. Under fully anerobic conditions, G. thermoglucosidasius M10EXG used a mixed acid fermentation process and exhibited a maximum ethanol yield of 0.38+-0.07 mol mol-1 glucose. In silico flux balance modeling demonstrates that lactate and acetate production from G. thermoglucosidasius M10EXG reduces the maximum ethanol yieldby approximately threefold, thus indicating that both pathways should be modified to maximize ethanol production.

  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, 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 are found among the colorless sulfur bacteria that oxidize hydrogen sulfide to sulfate with oxygen or nitrate. The several-cm-long filamentous species can penetrate up through the ca 500-mum-thick diffusive boundary layer and may thereby reach into water containing their electron acceptor, oxygen or nitrate. By their ability to store vast quantities of both nitrate and elemental sulfur in the cells, these bacteria have become independent of the coexistence of their substrates. In fact, a close relative, T. namibiensis, can probably respire in the sulfidic mud for several months before again filling up their large vacuoles with nitrate.

  8. Bacteria bites

    Science.gov (United States)

    Naturally occurring bacteria may be a future solution for myriad pollution problems, mounting laboratory evidence suggests. Last month, USGS scientists reported in Nature that microbes living in oxygen-free sediments can break down derivatives of hydrofluorocarbons, which are among the compounds under consideration to replace ozone-destroying chlorofluorocarbons (CFCs). And now, another USGS scientist reports in the July 14 Nature that microbes which degrade toxic and carcinogenic aromatic hydrocarbons like benzene and toluene can be boosted with an iron additive or chemical binder to work in anaerobic conditions that are commonly found in heavily polluted aquifers. Previously, scientists thought the bacteria could reduce the hard pollutants only if plenty of dissolved oxygen was in the water. Other bacteria have been shown to convert uranium to a highly insoluble form in cbntaminated waters as well.

  9. X-ray crystallographic studies of the alanine-specific racemase from Bacillus stearothermophilus. Overproduction, crystallization, and preliminary characterization.

    Science.gov (United States)

    Neidhart, D J; Distefano, M D; Tanizawa, K; Soda, K; Walsh, C T; Petsko, G A

    1987-11-15

    To facilitate large-scale purification and crystallographic study, we have subcloned the gene for the alanine racemase of Bacillus stearothermophilus from pICR401 (Inagaki, K., Tanizawa, K., Badet, B., Walsh, C. T., Tanaka, H., and Soda, K. (1986) Biochemistry 25, 3268-3274) and overproduced the enzyme in Escherichia coli W3110 lacIq using the tac promoter of PKK223-3. This system yields alanine racemase as 6% of the bacterial cytosolic protein. Purification by a modification of the procedure of Inagake et al. yielded 75 mg of homogeneous alanine racemase from 30 g of cells (wet weight). Large, well-formed crystals of alanine racemase have been grown from polyethylene glycol 8000 using vapor diffusion. These crystals have unit cell dimensions a = 85.3 A, b = 110.0 A, and c = 89.9 A. The crystals belong to space group P2(1), with beta fortuitously equal to 90 degrees within experimental error; however, they are frequently twinned by second order pseudomerohedry with twin fraction (the ratio of the volume of the smaller twin domain to the total volume of the crystal) ranging from about 0 to 0.5. Fortunately, for crystals with low twin fraction, computational methods have been developed for the analysis and correction of simple twinning (Fisher, R. G., and Sweet, R. M. (1980) Acta Crystallogr. A36, 755-760). The crystals contain two alpha 2 dimers of alanine racemase in the asymmetric unit. We have identified several potentially useful heavy atom derivatives in low resolution screening experiments and are proceeding with high resolution data collection. PMID:3680197

  10. Cation-selectivity of the L-glutamate transporters of Escherichia coli, Bacillus stearothermophilus and Bacillus caldotenax: dependence on the environment in which the proteins are expressed.

    Science.gov (United States)

    Tolner, B; Ubbink-Kok, T; Poolman, B; Konings, W N

    1995-10-01

    L-Glutamate transport by the H(+)-glutamate and Na(+)-glutamate symport proteins of Escherichia coli K-12 (GltPEc and GltSEc, respectively) and the Na(+)-H(+)-glutamate symport proteins of Bacillus stearothermophilus (GltTBs) and Bacillus caldotenax (GltTBc) was studied in membrane vesicles derived from cells in which the proteins were either homologously or heterologously expressed. Substrate and inhibitor specificity studies indicate that GltPEc, GltTBs and GltTBc fall into the same group of transporters, whereas GltSEc is distinctly different from the others. Also, the cation specificity of GltSEc is different; GltSEc transported L-glutamate with (at least) two Na+, whereas GltPEc, GltTBs and GltTBc catalysed an electrogenic symport of L-glutamate with > or = two H+, i.e. when the proteins were expressed in E. coli. Surprisingly studies in membrane vesicles of B. stearothermophilus and B. caldotenax indicated a Na(+)-H(+)-L-glutamate symport for both GltTBs and GltTBc. The Na+ dependency of the GltT transporters in the Bacillus strains increased with temperature. These observations suggest that the conformation of the transport proteins in the E. coli and the Bacillus membranes differs, which influences the coupling ion selectivity. PMID:8596452

  11. Rumen bacteria

    International Nuclear Information System (INIS)

    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 1011 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (104-106/g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 102-104/g distributed over 5 genera). The occurrence of bacteriophage is well documented (107-109 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

  12. Use of extremophilic bacteria for second generation bioethanol production

    DEFF Research Database (Denmark)

    Tomás, Ana Faria; Karakashev, Dimitar Borisov

    The pursuit of ways to obtain viable alternatives to fossil fuels has been one of the main subjects in microbial biotechnology research in the last decade. Of all the possible fuel candidates, bioethanol is one of the most relevant, especially when considered for the transport sector. Its production from food crops, such as corn (starch) or sugar cane (sucrose) is already an established process, with the USA and Brazil supplying 86% of the market. The major challenge remains in the use of different waste sources – agricultural, forestry, animal and household waste - as a feedstock. The recalcitrance of these materials and their diverse sugar composition make the industrial yeast strains currently used unsuitable for a second generation bioethanol production process. One of the alternative strategies is the use of extreme thermophilic microorganisms. Currently, selected members from the genera Clostridium, Thermoanaerobacter, Geobacillus and Thermoanaerobacterium are among the best candidates. A new strain of Thermoanaerobacter, closely related to T. italicus and T. mathranii, has achieved 0.43 gethanol/gxylose, which is 83% of the theoretical yield of ethanol based on xylose and the highest value for a wild type strain reported so far. However, productivity and titer values comparable to a first generation process are yet to be achieved. Metabolic engineering to redirect the metabolism from mixed-product fermentation to ethanol production is one of the solutions proposed to improve the performance of extreme thermophilic bacteria.

  13. Use of 'small but smart' libraries to enhance the enantioselectivity of an esterase from Bacillus stearothermophilus towards tetrahydrofuran-3-yl acetate.

    Science.gov (United States)

    Nobili, Alberto; Gall, Markus G; Pavlidis, Ioannis V; Thompson, Mark L; Schmidt, Marlen; Bornscheuer, Uwe T

    2013-07-01

    Two libraries of simultaneous double mutations in the active site region of an esterase from Bacillus stearothermophilus were constructed to improve the enantioselectivity in the hydrolysis of tetrahydrofuran-3-yl acetate. As screening of large mutant libraries is hampered by the necessity for GC/MS analysis, mutant libraries were designed according to a 'small but smart' concept. The design of focused libraries was based on data derived from a structural alignment of 3317 amino acid sequences of ?/?-hydrolase fold enzymes with the bioinformatic tool 3DM. In this way, the number of mutants to be screened was substantially reduced as compared with a standard site-saturation mutagenesis approach. Whereas the wild-type esterase showed only poor enantioselectivity (E = 4.3) in the hydrolysis of (S)-tetrahydrofuran-3-yl acetate, the best variants obtained with this approach showed increased E-values of up to 10.4. Furthermore, some variants with inverted enantiopreference were found. PMID:23331978

  14. Expression of genes encoding the E2 and E3 components of the Bacillus stearothermophilus pyruvate dehydrogenase complex and the stoichiometry of subunit interaction in assembly in vitro.

    Science.gov (United States)

    Lessard, I A; Domingo, G J; Borges, A; Perham, R N

    1998-12-01

    Genes encoding the dihydrolipoyl acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3) components of the pyruvate dehydrogenase (PDH) multienzyme complex from Bacillus stearothermophilus were overexpressed in Escherichia coli. The E2 component was purified as a large soluble aggregate (molecular mass > 1 x 10(6) Da) with the characteristic 532 symmetry of an icosahedral (60-mer) structure, and the E3 as a homodimer with a molecular mass of 110 kDa. The recombinant E2 component in vitro was capable of binding either 60 E3(alpha2) dimers or 60 heterotetramers (alpha2beta2) of the pyruvate decarboxylase (E1) component (also the product of B. stearothermophilus genes overexpressed in E. coli). Assembling the E2 polypeptide chain into the icosahedral E2 core did not impose any restriction on the binding of E1 or E3 to the peripheral subunit-binding domain in each E2 chain. This has important consequences for the stoichiometry of the assembled complex in vivo. The lipoyl domain of the recombinant E2 protein was found to be unlipoylated, but it could be correctly post-translationally modified in vitro using a recombinant lipoate protein ligase from E. coli. The lipoylated E2 component was able to bind recombinant E1 and E3 components in vitro to generate a PDH complex with a catalytic activity comparable with that of the wild-type enzyme. Reversible unfolding of the recombinant E2 and E3 components in 6 M guanidine hydrochloride was possible in the absence of chaperonins, with recoveries of enzymic activities of 95% and 85%, respectively. However, only 26% of the E1 enzyme activity was recovered under the same conditions as a result of irreversible denaturation of both E1alpha and E1beta. This represents the first complete post-translational modification and assembly of a fully active PDH complex from recombinant proteins in vitro. PMID:9874216

  15. [Physiological and phylogenetic diversity of thermophilic spore-forming hydrocarbon-oxidizing bacteria from oil fields].

    Science.gov (United States)

    Nazina, T N; Turova, T P; Poltaraus, A B; Novikova, E V; Ivanova, A E; Grigor'ian, A A; Lysenko, A M; Beliaev, S S

    2000-01-01

    The distribution and population density of aerobic hydrocarbon-oxidizing bacteria in the high-temperature oil fields of Western Siberia, Kazakhstan, and China were studied. Seven strains of aerobic thermophilic spore-forming bacteria were isolated from the oil fields and studied by microbiological and molecular biological methods. Based on the 16S rRNA gene sequences, phenotypic characteristics, and the results of DNA-DNA hybridization, the taxonomic affiliation of the isolates was tentatively established. The strains were assigned to the first and fifth subgroups of the genus Bacillus on the phylogenetic branch of the gram-positive bacteria. Strains B and 421 were classified as B. licheniformis. Strains X and U, located between B. stearothermophilus and B. thermocatenulatus on the phylogenetic tree, and strains K, Sam, and 34, related but not identical to B. thermodenitrificans and B. thermoleovorans, undoubtedly represent two new species. Phylogenetically and metabolically related representatives of thermophilic bacilli were found to occur in geographically distant oil fields. PMID:10808498

  16. Evaluation of peracetic acid sanitizers efficiency against spores isolated from spoiled cans in suspension and on stainless steel surfaces.

    Science.gov (United States)

    André, S; Hédin, S; Remize, F; Zuber, F

    2012-02-01

    The aim of this study was to determine the inactivation effect of industrial formulations of peracetic acid biocides on bacterial spores adhering to stainless steel surfaces. A standardized protocol was used to validate biocide activity against spores in suspension. To validate sporicidal activity under practical conditions, we developed an additional protocol to simulate industrial sanitization of stainless steel surfaces with a foam sanitizer. Spores of three spore-forming bacteria, Clostridium sporogenes PA3679, Geobacillus stearothermophilus, and Moorella thermoacetica/thermoautotrophica, were sprayed onto stainless steel as bioaerosols. Sporicidal activity was high against the C. sporogenes spore suspension, with more than 5 log CFU ml(-1) destroyed at all liquid biocide contact times. Sporicidal activity also was high against G. stearothermophilus and M. thermoacetica/thermoautotrophica spores after 30 min of contact, but we found no population reduction at the 5-min contact time for the highest sporicide concentration tested. The foam biocide effectively inactivated C. sporogenes spores adhered to stainless steel but had a reduced decontamination effect on other species. For G. stearothermophilus spores, sanitization with the foam sporicide was more efficient on horizontal steel than on vertical steel, but foam sanitization was ineffective against M. thermoacetica/thermoautotrophica whatever the position. These results highlight that decontamination efficiency may differ depending on whether spores are suspended in an aqueous solution or adhered to a stainless steel surface. Biocide efficiency must be validated using relevant protocols and bacteria representative of the microbiological challenges and issues affecting each food industry. PMID:22289600

  17. The Museum of Bacteria

    Science.gov (United States)

    The Museum of Bacteria serves as a clearinghouse of Web links on bacteria and bacteriology and also provides "crystal-clear information about many aspects of bacteria." The Museum of Bacteria is provided by the Foundation of Bacteria, a non-profit organization dedicated to promoting the field of bacteriology. Links are selected for a general audience, although one section is geared toward professionals in the field. Some of the latest features of the Museum are an "exhibit" on the good bacteria found in food and a Student Hall where students can present their own bacteria-related projects.

  18. Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminates bacteria of alcoholic fermentation

    International Nuclear Information System (INIS)

    The aim of this work was to study the influence of the bacteria Bacillus and Lactobacillus, as well as their metabolic products, in reduction of cellular viability of Saccharomyces cerevisiae, when in mixed culture of yeast and active and treated bacteria. Also was to evaluated an alternative medium (MCC) for the cultivation of bacteria and yeast, constituted of sugarcane juice diluted to 5 deg Brix and supplemented with yeast extract and peptone. The bacteria Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus fermentum and Lactobacillus plantarum were cultivated in association with yeast Saccharomyces cerevisiae (strain Y-904) for 72 h on 32 deg C, under agitation. The cellular viability, budding rate and population of S. cerevisiae, the total acidity, volatile acidity and pH of culture were determined from 0, 24, 48 e 72 h of mixed culture. Also were determined the initial and final of microorganism population across the pour plate method, in traditional culture medium (PCA for Bacillus, MRS-agar for Lactobacillus and YEPD-agar for yeast S. cerevisiae) and in medium constituted of sugarcane juice. The bacteria cultures were treated by heat sterilization (120 deg C for 20 minutes), antibacterial agent (Kamoran HJ in concentration 3,0 ppm) or irradiation (radiation gamma, with doses of 5,0 kGy for Lactobacillus and 15,0 kGy for Bacillus). The results of the present research showed that just the culture mediums more acids (with higher conulture mediums more acids (with higher concentrations of total and volatile acidity, and smaller values of pH), contaminated with active bacteria L. fermentum and B. subtilis, caused reduction on yeast cellular viability. Except the bacteria B. subtilis treated with radiation, the others bacteria treated by different procedures (heat, radiation e antibacterial) did not cause reduction on yeast cellular viability and population, indicating that the isolated presence of the cellular metabolic of theses bacteria was not enough to reduce the percentage of the yeast live cells and a density population. For all microorganisms, the counts obtained with the cultivation medium constituted of sugarcane juice were similar obtained in traditional mediums, probably because the alternative medium simulate the composition of sugarcane must, that the bacteria were isolated in industrial process of ethanol yield. However, the culture medium constituted of sugarcane juice could be replacing traditional culture mediums of yeast and bacteria tested in this work. (author)

  19. Improving production of hyperthermostable and high maltose-forming alpha-amylase by an extreme thermophile Geobacillus thermoleovorans using response surface methodology and its applications.

    Science.gov (United States)

    Uma Maheswar Rao, J L; Satyanarayana, T

    2007-01-01

    By cultivating Geobacillus thermoleovorans in shake flasks containing cane molasses medium at 70 degrees C, the fermentation variables were optimized by 'one variable at a time' approach followed by response surface methodology (RSM). The statistical model was obtained by central composite design (CCD) using three variables (cane-molasses, urea and inoculum density). An overall 1.6- and 2.1-fold increase in enzyme production was achieved in the optimized medium in shake flasks and fermenter, respectively. The alpha-amylase titre increased significantly in cane-molasses medium (60 U ml(-1)) as compared to that in the synthetic medium (26 U ml(-1)). Thus the cost of enzyme produced in cane molasses medium (0.823 euros per million U) was much lower than that produced in the synthetic starch-yeast extract-tryptone medium (18.52 euros per million U). The shelf life of bread was improved by supplementing dough with alpha-amylase, and thus, the enzyme was found to be useful in preventing the staling of bread. Reducing sugars liberated from 20% and 30% raw pearl millet starch were fermented to ethanol; ethanol production levels attained were 35.40 and 28.0 g l(-1), respectively. PMID:16473003

  20. Thermostable and alkalistable endoxylanase of the extremely thermophilic bacterium Geobacillus thermodenitrificans TSAA1: cloning, expression, characteristics and its applicability in generating xylooligosaccharides and fermentable sugars.

    Science.gov (United States)

    Verma, Digvijay; Anand, Ashima; Satyanarayana, T

    2013-05-01

    Xylanase encoding gene (1,224 bp) from Geobacillus thermodenitrificans was cloned in pET28a (+) vector and successfully expressed in Escherichia coli BL21 (DE3). The deduced amino acid sequence analysis revealed homology with that of glycosyl hydrolase (GH) 10 family with a high molecular mass (50 kDa). The purified recombinant xylanase is optimally active at pH 9.0 and 70 °C with T(1/2) of 10 min at 80 °C, and retains greater than 85 % activity after exposure to 70 °C for 180 min. The enzyme liberates xylose as well as xylooligosaccharides from birchwood xylan and agro-residues, and therefore, this is an endoxylanase. The xylan hydrolytic products (xylooligosaccharides, xylose, and xylobiose) find application as prebiotics and in the production of bioethanol. The xylanase being thermostable and alkalistable, it has released chromophores and phenolics from the residual lignin of pulps, suggesting its utility in mitigating chlorine requirement in pulp bleaching. PMID:23479291

  1. Identificación de genes codificantes de enzimas de interés industrial en una cepa de bacteria termofílica aislada de aguas termanles de Salta (Argentina

    Directory of Open Access Journals (Sweden)

    Navas, L.E.

    2014-04-01

    Full Text Available Se aislaron dos bacterias termofílicas a partir de aguas termales de la provincia de Salta, Argentina. Estudios filogenéticos permitieron caracterizar los aislamientos como pertenecientes a los géneros Thermus y Geobacillus. Se determinó la secuencia nucleotídica parcial del genoma de Thermus sp. 2.9 con un equipo de secuenciación masiva de ADN de tecnología Roche 454. Se generaron 215.557 lecturas que proveen una cobertura aproximada de 40 veces el tamaño del genoma. Se realizó un análisis preliminar de las secuencias obtenidas para la identificación de regiones codificantes. Mediante el mismo se identificaron y caracterizaron genes que codifican enzimas utilizadas en procesos de transformación de alimentos y relacionadas con la degradación de polímeros, tales como xilanasas, proteasas, esterasas, lipasas, catalasas y galactosidasas. Este primer paso indica que este microorganismo es un potencial productor de enzimas termofílicas que podrían ser aplicadas en la industria alimentaria.

  2. Identificación de genes codificantes de enzimas de interés industrial en una cepa de bacteria termofílica aislada de aguas termales de Salta (Argentina)

    Scientific Electronic Library Online (English)

    L.E, Navas; A.F, Amadío; I, Fuxan; R.O, Zandomeni.

    2014-04-01

    Full Text Available Se aislaron dos bacterias termofílicas a partir de aguas termales de la provincia de Salta, Argentina. Estudios filogenéticos permitieron caracterizar los aislamientos como pertenecientes a los géneros Thermus y Geobacillus. Se determinó la secuencia nucleotídica parcial del genoma de Thermus sp. 2. [...] 9 con un equipo de secuenciación masiva de ADN de tecnología Roche 454. Se generaron 215.557 lecturas que proveen una cobertura aproximada de 40 veces el tamaño del genoma. Se realizó un análisis preliminar de las secuencias obtenidas para la identificación de regiones codificantes. Mediante el mismo se identificaron y caracterizaron genes que codifican enzimas utilizadas en procesos de transformación de alimentos y relacionadas con la degradación de polímeros, tales como xilanasas, proteasas, esterasas, lipasas, catalasas y galactosidasas. Este primer paso indica que este microorganismo es un potencial productor de enzimas termofílicas que podrían ser aplicadas en la industria alimentaria. Abstract in english Two thermophilic bacteria were isolated from a hot spring in Salta, northwest Argentina. Phylogenic analysis indicates that the isolates belong to the Thermus and Geobacillus genera. We have undertaken the DNA sequencing of the complete genome from the isolate Thermus sp. 2.9 using Roche 454 technol [...] ogy. Two hundred and fifteen thousand readings were obtained providing approximately 40 fold coverage of the genome. A first round of analysis of the contigs was made to identify proteins coded in the genome. We report the identification and characterization of several genes coding for enzymes related to the degradation of polymers such as xylanases, proteases, esterases, lipases, catalase and galactosidases. These enzymes may be useful in processes to transform commodities from agriculture and valuable tools in the food industry.

  3. Viabilidade celular de Saccharomyces cerevisiae cultivada em associação com bactérias contaminantes da fermentação alcoólica / Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminant bacteria of alcoholic fermentation

    Scientific Electronic Library Online (English)

    Thais de Paula, Nobre; Jorge, Horii; André Ricardo, Alcarde.

    2007-03-01

    Full Text Available O objetivo deste trabalho foi estudar a influência de bactérias dos gêneros Bacillus e Lactobacillus, bem como de seus produtos metabólicos, na redução da viabilidade celular de leveduras Saccharomyces cerevisiae. As bactérias Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lacto [...] bacillus fermentum e Lactobacillus plantarum foram cultivadas em associação com a levedura S. cerevisiae (cepa Y-904) por 72 horas a 32 °C, sob agitação. A viabilidade celular, a taxa de brotamento e a população de células de S. cerevisiae e a acidez total, a acidez volátil e o pH dos meios de cultivos foram determinados às 0, 24, 48 e 72 horas do cultivo misto. As culturas de bactérias foram tratadas através do calor, de agente antimicrobiano e de irradiação. Os resultados mostraram que apenas os meios de cultivo mais acidificados, contaminados com as bactérias ativas L. fermentum e B. subtilis, provocaram redução na viabilidade celular de S. cerevisiae. Excetuando a bactéria B. subtilis tratada com radiação gama, as demais bactérias tratadas pelos diferentes processos (calor, irradiação e antimicrobiano) não causaram diminuição da viabilidade celular e da população de S. cerevisiae, indicando que a presença isolada dos metabólitos celulares dessas bactérias não foi suficiente para reduzir a porcentagem de células vivas de S. cerevisiae. Abstract in english The aim of this project was to study the influence of the bacteria Bacillus and Lactobacillus, as well as their metabolic products to decrease the cellular viability of the yeast Saccharomyces cerevisiae. The bacteria Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus [...] fermentum and Lactobacillus plantarum were cultivated in association with yeast S. cerevisiae (strain Y-904) for 72 hours at 32 ºC under agitation. The cellular viability, budding rate and population of S. Cerevisiae and the total acidity, volatile acidity and pH of culture medium were determined at 0, 24, 48 and 72 hours of incubation of the mixed culture. The bacteria cultures were treated by heat sterilization, antibacterial agent and irradiation. The results showed that only the more acidified culture medium, contaminated with active bacteria L. fermentum and B. subtilis, caused a reduction in the yeast cellular viability. Except for the bacteria B. subtilis treated for radiation, the other bacteria treated by the different procedures (heat, radiation and antibacterial) did not cause a reduction in the cellular viability of S. cerevisiae, indicating that the isolated presence of the cellular metabolic of these bacteria was not enough to reduce the percentage of the living yeast cells.

  4. Viabilidade celular de Saccharomyces cerevisiae cultivada em associação com bactérias contaminantes da fermentação alcoólica Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminant bacteria of alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Thais de Paula Nobre

    2007-03-01

    Full Text Available O objetivo deste trabalho foi estudar a influência de bactérias dos gêneros Bacillus e Lactobacillus, bem como de seus produtos metabólicos, na redução da viabilidade celular de leveduras Saccharomyces cerevisiae. As bactérias Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus fermentum e Lactobacillus plantarum foram cultivadas em associação com a levedura S. cerevisiae (cepa Y-904 por 72 horas a 32 °C, sob agitação. A viabilidade celular, a taxa de brotamento e a população de células de S. cerevisiae e a acidez total, a acidez volátil e o pH dos meios de cultivos foram determinados às 0, 24, 48 e 72 horas do cultivo misto. As culturas de bactérias foram tratadas através do calor, de agente antimicrobiano e de irradiação. Os resultados mostraram que apenas os meios de cultivo mais acidificados, contaminados com as bactérias ativas L. fermentum e B. subtilis, provocaram redução na viabilidade celular de S. cerevisiae. Excetuando a bactéria B. subtilis tratada com radiação gama, as demais bactérias tratadas pelos diferentes processos (calor, irradiação e antimicrobiano não causaram diminuição da viabilidade celular e da população de S. cerevisiae, indicando que a presença isolada dos metabólitos celulares dessas bactérias não foi suficiente para reduzir a porcentagem de células vivas de S. cerevisiae.The aim of this project was to study the influence of the bacteria Bacillus and Lactobacillus, as well as their metabolic products to decrease the cellular viability of the yeast Saccharomyces cerevisiae. The bacteria Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus fermentum and Lactobacillus plantarum were cultivated in association with yeast S. cerevisiae (strain Y-904 for 72 hours at 32 ºC under agitation. The cellular viability, budding rate and population of S. Cerevisiae and the total acidity, volatile acidity and pH of culture medium were determined at 0, 24, 48 and 72 hours of incubation of the mixed culture. The bacteria cultures were treated by heat sterilization, antibacterial agent and irradiation. The results showed that only the more acidified culture medium, contaminated with active bacteria L. fermentum and B. subtilis, caused a reduction in the yeast cellular viability. Except for the bacteria B. subtilis treated for radiation, the other bacteria treated by the different procedures (heat, radiation and antibacterial did not cause a reduction in the cellular viability of S. cerevisiae, indicating that the isolated presence of the cellular metabolic of these bacteria was not enough to reduce the percentage of the living yeast cells.

  5. Characterization and functional expression in Escherichia coli of the sodium/proton/glutamate symport proteins of Bacillus stearothermophilus and Bacillus caldotenax.

    Science.gov (United States)

    Tolner, B; Poolman, B; Konings, W N

    1992-10-01

    The genes encoding the Na+/H+/L-glutamate symport proteins of the thermophilic organisms Bacillus stearothermophilus (gltTBs) and Bacillus caldotenax (gltTBc) were cloned by complementation of Escherichia coli JC5412 for growth on glutamate as sole source of carbon, energy and nitrogen. The nucleotide sequences of the gltTBs and gltTBc genes were determined. In both cases the translated sequences corresponded with proteins of 421 amino acid residues (96.7% amino acid identity between GltTBs and GltTBc). Putative promoter, terminator and ribosome-binding-site sequences were found in the flanking regions. These expression signals were functional in E. coli. The hydropathy profiles indicate that the proteins are hydrophobic and could form 12 membrane-spanning regions. The Na+/H+ coupled L-glutamate symport proteins GltTBs and GltTBc are homologous to the strictly H+ coupled L-glutamate transport protein of E. coli K-12 (overall 57.2% identity). Functional expression of glutamate transport activity was demonstrated by uptake of glutamate in whole cells and membrane vesicles. In accordance with previous observations (de Vrij et al., 1989; Heyne et al., 1991), glutamate uptake was driven by the electrochemical gradients of sodium ions and protons. PMID:1359385

  6. 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 ...

  7. Bacteria Inactivation During Lithotripsy

    Science.gov (United States)

    del Sol Quintero, María; Mora, Ulises; Gutiérrez, Jorge; Mues, Enrique; Castaño, Eduardo; Fernández, Francisco; Loske, Achim M.

    2006-09-01

    The influence of extracorporeal and intracorporeal lithotripsy on the viability of bacteria contained inside artificial kidney stones was investigated in vitro. Two different bacteria were exposed to the action of one extracorporeal shock wave generator and four intracorporeal lithotripters.

  8. Lactic Acid Bacteria

    Science.gov (United States)

    This on-line exercise is focused on lactic acid bacteria, a group of related bacteria that produce lactic acid as a result of carbohydrate fermentation. It includes a protocol for the enrichment of lactic acid bacteria from enriched samples (like yogurt, sauerkraut, decaying plant matter, and tooth plaque). Three parameters are measured: growth, culture diversity, and pH. The exercise also includes instructions for the isolation of some of these bacteria by using the streak-plate method.

  9. Improvement of Thermal Stability via Outer-Loop Ion Pair Interaction of Mutated T1 Lipase from Geobacillus zalihae Strain T1

    Directory of Open Access Journals (Sweden)

    Mahiran Basri

    2012-01-01

    Full Text Available Mutant D311E and K344R were constructed using site-directed mutagenesis to introduce an additional ion pair at the inter-loop and the intra-loop, respectively, to determine the effect of ion pairs on the stability of T1 lipase isolated from Geobacillus zalihae. A series of purification steps was applied, and the pure lipases of T1, D311E and K344R were obtained. The wild-type and mutant lipases were analyzed using circular dichroism. The Tm for T1 lipase, D311E lipase and K344R lipase were approximately 68.52 °C, 70.59 °C and 68.54 °C, respectively. Mutation at D311 increases the stability of T1 lipase and exhibited higher Tm as compared to the wild-type and K344R. Based on the above, D311E lipase was chosen for further study. D311E lipase was successfully crystallized using the sitting drop vapor diffusion method. The crystal was diffracted at 2.1 Å using an in-house X-ray beam and belonged to the monoclinic space group C2 with the unit cell parameters a = 117.32 Å, b = 81.16 Å and c = 100.14 Å. Structural analysis showed the existence of an additional ion pair around E311 in the structure of D311E. The additional ion pair in D311E may regulate the stability of this mutant lipase at high temperatures as predicted in silico and spectroscopically.

  10. Bacteria Are Everywhere!

    Science.gov (United States)

    AMPS GK-12 Program,

    Students are introduced to the concept of engineering biological organisms and studying their growth to be able to identify periods of fast and slow growth. They learn that bacteria are found everywhere, including on the surfaces of our hands. Student groups study three different conditions under which bacteria are found and compare the growth of the individual bacteria from each source. In addition to monitoring the quantity of bacteria from differ conditions, they record the growth of bacteria over time, which is an excellent tool to study binary fission and the reproduction of unicellular organisms.

  11. Stereospecific production of the herbicide phosphinothricin (glufosinate): purification of aspartate transaminase from Bacillus stearothermophilus, cloning of the corresponding gene, aspC, and application in a coupled transaminase process.

    OpenAIRE

    Bartsch, K.; Schneider, R.; Schulz, A.

    1996-01-01

    We have isolated and characterized an aspartate transaminase (glutamate:oxalacetate transaminase, EC 2.6.1.1) from the thermophilic microorganism Bacillus stearothermophilus. The purified enzyme has a molecular mass of 40.5 kDa by sodium dodecyl sulfate gel analysis, a temperature optimum of 95 degrees C, and a pH optimum of 8.0. The corresponding gene, aspC, was cloned and overexpressed in Escherichia coli. The recombinant glutamate:oxalacetate transaminase protein was used in immobilized fo...

  12. Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminates bacteria of alcoholic fermentation;Viabilidade celular de Saccharomyces cerevisiae cultivada em associacao com bacterias contaminantes da fermentacao alcoolica

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, Thais de Paula

    2005-07-01

    The aim of this work was to study the influence of the bacteria Bacillus and Lactobacillus, as well as their metabolic products, in reduction of cellular viability of Saccharomyces cerevisiae, when in mixed culture of yeast and active and treated bacteria. Also was to evaluated an alternative medium (MCC) for the cultivation of bacteria and yeast, constituted of sugarcane juice diluted to 5 deg Brix and supplemented with yeast extract and peptone. The bacteria Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus fermentum and Lactobacillus plantarum were cultivated in association with yeast Saccharomyces cerevisiae (strain Y-904) for 72 h on 32 deg C, under agitation. The cellular viability, budding rate and population of S. cerevisiae, the total acidity, volatile acidity and pH of culture were determined from 0, 24, 48 e 72 h of mixed culture. Also were determined the initial and final of microorganism population across the pour plate method, in traditional culture medium (PCA for Bacillus, MRS-agar for Lactobacillus and YEPD-agar for yeast S. cerevisiae) and in medium constituted of sugarcane juice. The bacteria cultures were treated by heat sterilization (120 deg C for 20 minutes), antibacterial agent (Kamoran HJ in concentration 3,0 ppm) or irradiation (radiation gamma, with doses of 5,0 kGy for Lactobacillus and 15,0 kGy for Bacillus). The results of the present research showed that just the culture mediums more acids (with higher concentrations of total and volatile acidity, and smaller values of pH), contaminated with active bacteria L. fermentum and B. subtilis, caused reduction on yeast cellular viability. Except the bacteria B. subtilis treated with radiation, the others bacteria treated by different procedures (heat, radiation e antibacterial) did not cause reduction on yeast cellular viability and population, indicating that the isolated presence of the cellular metabolic of theses bacteria was not enough to reduce the percentage of the yeast live cells and a density population. For all microorganisms, the counts obtained with the cultivation medium constituted of sugarcane juice were similar obtained in traditional mediums, probably because the alternative medium simulate the composition of sugarcane must, that the bacteria were isolated in industrial process of ethanol yield. However, the culture medium constituted of sugarcane juice could be replacing traditional culture mediums of yeast and bacteria tested in this work. (author)

  13. Darwin y las bacterias Darwin and bacteria

    Directory of Open Access Journals (Sweden)

    Walter Ledermann D

    2009-02-01

    Full Text Available Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva.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. Darwin y las bacterias / Darwin and bacteria

    Scientific Electronic Library Online (English)

    Walter, Ledermann D.

    2009-02-01

    Full Text Available Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en [...] el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva. Abstract in english 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 t [...] ook 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.

  15. Bacteria: Fossil Record

    Science.gov (United States)

    This description of the fossil record of bacteria focuses on one particular group of bacteria, the cyanobacteria or blue-green algae, which have left a fossil record that extends far back into the Precambrian. The oldest cyanobacteria-like fossils known are nearly 3.5 billion years old and are among the oldest fossils currently known. Cyanobacteria are larger than most bacteria and may secrete a thick cell wall. More importantly, cyanobacteria may form large layered structures, called stromatolites (if more or less dome-shaped) or oncolites (if round). The site also refers to pseudomorphs of pyrite and siderite, and a group of bacteria known as endolithic. Two links are available for more information. One provides information on the discovery of possible remains of bacteria-like organisms on a meteorite from Mars and the other has a research report on fossilized filamentous bacteria and other microbes, found in Cretaceous amber.

  16. Interspecies communication in bacteria

    OpenAIRE

    Federle, Michael J.; Bassler, Bonnie L.

    2003-01-01

    Until recently, bacteria were considered to live rather asocial, reclusive lives. New research shows that, in fact, bacteria have elaborate chemical signaling systems that enable them to communicate within and between species. One signal, termed AI-2, appears to be universal and facilitates interspecies communication. Many processes, including virulence factor production, biofilm formation, and motility, are controlled by AI-2. Strategies that interfere with communication in bacteria are bein...

  17. Chemical communication among bacteria

    OpenAIRE

    Taga, Michiko E.; Bassler, Bonnie L.

    2003-01-01

    Cell–cell communication in bacteria is accomplished through the exchange of chemical signal molecules called autoinducers. This process, called quorum sensing, allows bacteria to monitor their environment for the presence of other bacteria and to respond to fluctuations in the number and/or species present by altering particular behaviors. Most quorum-sensing systems are species- or group-specific, which presumably prevents confusion in mixed-species environments. However, some quorum-sensi...

  18. 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.

  19. Multidrug Resistance in Bacteria

    OpenAIRE

    Nikaido, Hiroshi

    2009-01-01

    Large amounts of antibiotics used for human therapy, as well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur b...

  20. Introduction to Bacteria

    Science.gov (United States)

    DiscoverySchool.com

    2007-12-12

    This science site has students research how bacteria move, where they live, and how they reproduce; learn how bacteria can be helpful or harmful; and create a design illustrating what they have learned about bacteria. Included in the lesson plan are the objectives, needed materials and Web sites, procedures, discussion questions, evaluation, extensions, suggested reading, and vocabulary. Teachers can link to Teaching Tools to create custom worksheets, puzzles, and quizzes. A printable version of the lesson plan can be downloaded. The video Bacteria, Viruses and Allergies can be purchased and comprehension questions and answers can be downloaded.

  1. Bacteria-Antagonists

    International Science & Technology Center (ISTC)

    Development of Biological Control Agents Through Use of Recombinant Antagonistic Bacteria Possessing Variable Mechanisms of Antagonisms, High Colonizing Capacity and Marker Traits for their Monitoring in Nature

  2. A modeling study by response surface methodology and artificial neural network on culture parameters optimization for thermostable lipase production from a newly isolated thermophilic Geobacillus sp. strain ARM

    Directory of Open Access Journals (Sweden)

    Basri Mahiran

    2008-12-01

    Full Text Available Abstract Background Thermostable bacterial lipases occupy a place of prominence among biocatalysts owing to their novel, multifold applications and resistance to high temperature and other operational conditions. The capability of lipases to catalyze a variety of novel reactions in both aqueous and nonaqueous media presents a fascinating field for research, creating interest to isolate novel lipase producers and optimize lipase production. The most important stages in a biological process are modeling and optimization to improve a system and increase the efficiency of the process without increasing the cost. Results Different production media were tested for lipase production by a newly isolated thermophilic Geobacillus sp. strain ARM (DSM 21496 = NCIMB 41583. The maximum production was obtained in the presence of peptone and yeast extract as organic nitrogen sources, olive oil as carbon source and lipase production inducer, sodium and calcium as metal ions, and gum arabic as emulsifier and lipase production inducer. The best models for optimization of culture parameters were achieved by multilayer full feedforward incremental back propagation network and modified response surface model using backward elimination, where the optimum condition was: growth temperature (52.3°C, medium volume (50 ml, inoculum size (1%, agitation rate (static condition, incubation period (24 h and initial pH (5.8. The experimental lipase activity was 0.47 Uml-1 at optimum condition (4.7-fold increase, which compared well to the maximum predicted values by ANN (0.47 Uml-1 and RSM (0.476 Uml-1, whereas R2 and AAD were determined as 0.989 and 0.059% for ANN, and 0.95 and 0.078% for RSM respectively. Conclusion Lipase production is the result of a synergistic combination of effective parameters interactions. These parameters are in equilibrium and the change of one parameter can be compensated by changes of other parameters to give the same results. Though both RSM and ANN models provided good quality predictions in this study, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities. On the other hand, ANN has the disadvantage of requiring large amounts of training data in comparison with RSM. This problem was solved by using statistical experimental design, to reduce the number of experiments.

  3. Inactivation of biofilm bacteria.

    OpenAIRE

    LeChevallier, M. W.; Cawthon, C D; Lee, R. G.

    1988-01-01

    The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found ...

  4. Halophilic anaerobic fermentative bacteria.

    Science.gov (United States)

    Kivistö, Anniina T; Karp, Matti T

    2011-04-10

    In hypersaline environments bacteria are exposed to a high osmotic pressure caused by the surrounding high salt concentrations. Halophilic microorganisms have specific strategies for balancing the osmotic pressure and surviving in these extreme conditions. Halophilic fermentative bacteria form taxonomically and phylogenetically a coherent group mainly belonging to the order Halanaerobiales. In this review, halophilic anaerobic fermentative bacteria in terms of taxonomy and phylogeny, special characteristics, survival strategies, and potential for biotechnological applications in a wide variety of branches, such as production of hydrogen, are discussed. PMID:20804793

  5. Can bacteria save the planet?

    OpenAIRE

    Hunter, Philip

    2010-01-01

    Bacteria might just hold the key to preserving the environment for our great grandchildren. Philip Hunter explores some of the novel ways in which systems biology and biotechnology are harnessing bacteria to produce renewable energy and clean up pollution.

  6. Three Activities: Bacteria Study, Micro Study, and Bacteria Killers

    Science.gov (United States)

    This resource provides a problem-based activity on risk assessment of environmental health issues. The lesson consists of three related activities: Bacteria Study, Micro Study and Bacteria Killers. "Bacteria Study" gives students hands-on experience with the concepts of epidemiology. "Micro Study" has students sketch, observe, and compare different types of bacteria that can grow in moist conditions. "Bacteria Killers" has students determine what kills bateria, especially in common household products. Detailed instructions are provided for each activity. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

  7. Crystallization and preliminary X-ray diffraction studies of two thermostable ?-galactosidases from glycoside hydrolase family 36

    OpenAIRE

    Foucault, M.; Watzlawick, H.; Mattes, R.; Haser, R.; Gouet, P.

    2006-01-01

    The ?-galactosidases AgaA, AgaB and AgaA A355E mutant from Geobacillus stearothermophilus have been overexpressed in Escherichia coli. Crystals of AgaB and AgaA A355E have been obtained by the vapour-diffusion method and synchrotron data have been collected to 2.0 and 2.8?Å resolution, respectively.

  8. A thermostable transketolase evolved for aliphatic aldehyde acceptors.

    Science.gov (United States)

    Yi, Dong; Saravanan, Thangavelu; Devamani, Titu; Charmantray, Franck; Hecquet, Laurence; Fessner, Wolf-Dieter

    2015-01-11

    Directed evolution of the thermostable transketolase from Geobacillus stearothermophilus based on a pH-based colorimetric screening of smart libraries yielded several mutants with up to 16-fold higher activity for aliphatic aldehydes and high enantioselectivity (>95% ee) in the asymmetric carboligation step. PMID:25415647

  9. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  10. Glacial lake hides bacteria

    Science.gov (United States)

    Mark Peplow

    This article highlights the published work of a geomicrobiology research team led by Eric Gaidos from the University of Hawaii and Brian Lanoil, from the University of California, Riverside. This group reports the identification of bacteria from an Icelandic sub-glacial lake, and how the collection and description of these microorganisms immured within glacial ice and sub-surface water serve as a model in the search for extra-terrestrial life.

  11. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication 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.

  12. The Cyclic Antibacterial Peptide Enterocin AS-48: Isolation, Mode of Action, and Possible Food Applications

    Directory of Open Access Journals (Sweden)

    María José Grande Burgos

    2014-12-01

    Full Text Available Enterocin AS-48 is a circular bacteriocin produced by Enterococcus. It contains a 70 amino acid-residue chain circularized by a head-to-tail peptide bond. The conformation of enterocin AS-48 is arranged into five alpha-helices with a compact globular structure. Enterocin AS-48 has a wide inhibitory spectrum on Gram-positive bacteria. Sensitivity of Gram-negative bacteria increases in combination with outer-membrane permeabilizing treatments. Eukaryotic cells are bacteriocin-resistant. This cationic peptide inserts into bacterial membranes and causes membrane permeabilization, leading ultimately to cell death. Microarray analysis revealed sets of up-regulated and down-regulated genes in Bacillus cereus cells treated with sublethal bacteriocin concentration. Enterocin AS-48 can be purified in two steps or prepared as lyophilized powder from cultures in whey-based substrates. The potential applications of enterocin AS-48 as a food biopreservative have been corroborated against foodborne pathogens and/or toxigenic bacteria (Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enterica and spoilage bacteria (Alicyclobacillus acidoterrestris, Bacillus spp., Paenibacillus spp., Geobacillus stearothermophilus, Brochothrix thermosphacta, Staphylococcus carnosus, Lactobacillus sakei and other spoilage lactic acid bacteria. The efficacy of enterocin AS-48 in food systems increases greatly in combination with chemical preservatives, essential oils, phenolic compounds, and physico-chemical treatments such as sublethal heat, high-intensity pulsed-electric fields or high hydrostatic pressure.

  13. The Cyclic Antibacterial Peptide Enterocin AS-48: Isolation, Mode of Action, and Possible Food Applications.

    Science.gov (United States)

    Grande Burgos, María José; Pulido, Rubén Pérez; Del Carmen López Aguayo, María; Gálvez, Antonio; Lucas, Rosario

    2014-01-01

    Enterocin AS-48 is a circular bacteriocin produced by Enterococcus. It contains a 70 amino acid-residue chain circularized by a head-to-tail peptide bond. The conformation of enterocin AS-48 is arranged into five alpha-helices with a compact globular structure. Enterocin AS-48 has a wide inhibitory spectrum on Gram-positive bacteria. Sensitivity of Gram-negative bacteria increases in combination with outer-membrane permeabilizing treatments. Eukaryotic cells are bacteriocin-resistant. This cationic peptide inserts into bacterial membranes and causes membrane permeabilization, leading ultimately to cell death. Microarray analysis revealed sets of up-regulated and down-regulated genes in Bacillus cereus cells treated with sublethal bacteriocin concentration. Enterocin AS-48 can be purified in two steps or prepared as lyophilized powder from cultures in whey-based substrates. The potential applications of enterocin AS-48 as a food biopreservative have been corroborated against foodborne pathogens and/or toxigenic bacteria (Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enterica) and spoilage bacteria (Alicyclobacillus acidoterrestris, Bacillus spp., Paenibacillus spp., Geobacillus stearothermophilus, Brochothrix thermosphacta, Staphylococcus carnosus, Lactobacillus sakei and other spoilage lactic acid bacteria). The efficacy of enterocin AS-48 in food systems increases greatly in combination with chemical preservatives, essential oils, phenolic compounds, and physico-chemical treatments such as sublethal heat, high-intensity pulsed-electric fields or high hydrostatic pressure. PMID:25493478

  14. Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    ToddKlaenhammer

    2013-04-01

    Full Text Available Lactic acid bacteria (LAB are a diverse group of Gram-positive bacteria found in a vast array of environments including dairy products and the human gastrointestinal tract. In both niches, surface proteins play a crucial role in mediating interactions with the surrounding environment. The sortase enzyme is responsible for covalently coupling a subset of surface dependent proteins (SDPs to the cell wall of Gram-positive organisms through recognition of a conserved C-terminal LPXTG motif. Genomic sequencing of LAB and annotation has allowed for the identification of sortase and SDPs. Historically, sortase and SDPs were predominately investigated for their role in mediating pathogenesis. Identification of these proteins in LAB has shed light on their important roles in mediating nutrient acquisition through proteinase P as well as positive probiotic attributes including adhesion, mucus barrier function, and immune signaling. Furthermore, sortase expression signals in LAB have been exploited as a means to develop oral vaccines targeted to the gastrointestinal tract. In this review, we examine the collection of studies which evaluate sortase and SDPs in select species of dairy associated and health promoting LAB.

  15. Trail following by gliding bacteria.

    OpenAIRE

    Burchard, R. P.

    1982-01-01

    Slime trails, which are deposited on surfaces by gliding bacteria and which serve as preferential pathways for gliding motility, were tested for the species specificity of their support of movement. Among the pairs of bacteria tested, a variety of gliding bacteria and a flagellated bacterium moved along trails of unrelated species. Thus, the trails did not serve as pheromones. Rather, they may have guided gliding elasticotactically. Some biological implications of this finding are considered.

  16. M.BstF5I-2 and M.BstF5I-4 DNA methyltransferases from BstF5I restriction-modification system of Bacillus stearothermophilus F5.

    Science.gov (United States)

    Chernukhin, V A; Golikova, L N; Gonchar, D A; Abdurashitov, M A; Kashirina, Yu G; Netesova, N A; Degtyarev, S Kh

    2003-09-01

    The BstF5I restriction-modification system from Bacillus stearothermophilus F5 includes four site-specific DNA methyltransferases, thus differing from all known restriction-modification systems. Here we demonstrated for the first time that one bacterial cell can possess two pairs of methylases with identical substrate specificities (methylases BstF5I-1 and BstF5I-3 recognize GGATG, whereas methylases BstF5I-2 and BstF5I-4 recognize CATCC) that modify adenine residues on both DNA strands. Different chromatographic methods provide homogenous preparations of methylases BstF5I-2 and BstF5I-4. We estimated the principal kinetic parameters of the reaction of transfer of methyl group from the donor S-adenosyl-L-methionine to the recognition site 5;-CATCC-3; catalyzed by BstF5I-2 and BstF5I-4 DNA [N6-adenine]-methyltransferases from the BstF5I restriction-modification system. PMID:14606938

  17. Programmed Death in Bacteria

    Science.gov (United States)

    Lewis, Kim

    2000-01-01

    Programmed cell death (PCD) in bacteria plays an important role in developmental processes, such as lysis of the mother cell during sporulation of Bacillus subtilis and lysis of vegetative cells in fruiting body formation of Myxococcus xanthus. The signal transduction pathway leading to autolysis of the mother cell includes the terminal sporulation sigma factor E?K, which induces the synthesis of autolysins CwlC and CwlH. An activator of autolysin in this and other PCD processes is yet to be identified. Autolysis plays a role in genetic exchange in Streptococcus pneumoniae, and the gene for the major autolysin, lytA, is located in the same operon with recA. DNA from lysed cells is picked up by their neighbors and recombined into the chromosome by RecA. LytA requires an unknown activator controlled by a sensory kinase, VncS. Deletion of vncS inhibits autolysis and also decreases killing by unrelated antibiotics. This observation suggests that PCD in bacteria serves to eliminate damaged cells, similar to apoptosis of defective cells in metazoa. The presence of genes affecting survival without changing growth sensitivity to antibiotics (vncS, lytA, hipAB, sulA, and mar) indicates that bacteria are able to control their fate. Elimination of defective cells could limit the spread of a viral infection and donate nutrients to healthy kin cells. An altruistic suicide would be challenged by the appearance of asocial mutants without PCD and by the possibility of maladaptive total suicide in response to a uniformly present lethal factor or nutrient depletion. It is proposed that a low rate of mutation serves to decrease the probability that asocial mutants without PCD will take over the population. It is suggested that PCD is disabled in persistors, rare cells that are resistant to killing, to ensure population survival. It is suggested that lack of nutrients leads to the stringent response that suppresses PCD, producing a state of tolerance to antibiotics, allowing cells to discriminate between nutrient deprivation and unrepairable damage. High levels of persistors are apparently responsible for the extraordinary survival properties of bacterial biofilms, and genes affecting persistence appear to be promising targets for development of drugs aimed at eradicating recalcitrant infections. PCD in unicellular eukaryotes is also considered, including aging in Saccharomyces cerevisiae. Apoptosis-like elimination of defective cells in S. cerevisiae and protozoa suggests that all unicellular life forms evolved altruistic programmed death that serves a variety of useful functions. PMID:10974124

  18. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.

    2005-01-01

    Populations of bacterial cells often coordinate their responses to changes in their local environmental conditions through "quorum sensing", a cell-to-cell communication system employing small diffusible signal molecules. While there is considerable diversity in the chemistry of such signal molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical analysis which in turn has resulted in significant progress in understanding the molecular basis of quorum sensing-dependent gene expression. Consequently, the discovery and characterisation of natural molecules which antagonize quorum sensing-mediated responses has created new opportunities for the design of novel anti-infective agents which control infection through the attenuation of bacterial virulence.

  19. Urine Isn't Free of Bacteria

    Science.gov (United States)

    ... fullstory_151843.html Urine Isn't Free of Bacteria New study links bacteria found in urine in bladder to urinary incontinence ... News) -- Though it's commonly believed that urine is bacteria-free, normal urine is not sterile, a new ...

  20. Bacteria Growth Inquiry: Bodily Bacteria and Healthy Hygiene Habits

    Science.gov (United States)

    In this inquiry activity, students generate investigable questions to explore the link between hygiene/cleanliness and bacteria growth/population. The students will present their conclusions, and video clips containing additional information will be discussed.

  1. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.

    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 TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria.

  2. Dissipative Shocks behind Bacteria Gliding

    OpenAIRE

    Virga, Epifanio G.

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the fila...

  3. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  4. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  5. Microgravity effects on magnetotactic bacteria

    Science.gov (United States)

    Urban, James E.

    1998-01-01

    An unusual group of iron bacteria has recently been discovered which form inclusion bodies containing a form of iron oxide known as magnetite (ferrosoferric oxide, Fe3O4.) The inclusions are of a nano-particle size, are encased within a protein envelope, and are called magnetosomes. Magnetosomes are arranged adjacent to one another and parallel to the long axis of the cell such that cells appear to contain an electron-dense string of beads. The bacteria containing magnetosomes exhibit metal reductase activity, an activity critical to element recycling in nature, and the inclusions are a means for the organism to sequester reduced iron atoms and thereby keep iron reduction stoichiometry favorable. The magnetosomes also allow the bacteria to display magnetotaxis, which is movement in response to a magnetic field, such as the north or south magnetic poles. It is presumed that the bacteria use the alignment to the earth's magnetic field to orient themselves downward towards sediments where the habitat is favorable to their growth and metabolism. The comparatively few species of these bacteria isolated in the northern and southern hemispheres respond to magnetic north and south respectively, or alternatively respond only to the magnetic pole of the hemisphere from which they were isolated. This apparent dichotomy in response to magnetism could mean that the organisms are not responding to magnetism, per se, but instead are using the magnetosomes to respond to gravity. To resolve if magnetosomes respond to gravity in addition to magnetism we have used Magnetospirillum magnetotacticum, a well-studied magnetotactic bacterium isolated in the northern hemisphere, to examine magnetotactic behavior in the absence of gravity. Experiments to compare the orientation of Magnetospirillum magnetotacticum to north- or south-pole magnets were conducted in normal gravity and in the microgravity environments aboard the Space Shuttle and Space Station MIR. In each of the microgravity situations studied, bacteria were impaired in their ability to orient to magnets, suggesting that on earth the bacteria use magnetosomes to respond to gravity. These experiments could have significant commercial utility and could lead to the use of magnetosomes to direct biodegrading bacteria to contaminated aquifers or soils and likewise could be used to direct and localize bacteria used in element leaching and microbial mining.

  6. Genetic transfer in acidophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Roberto, F.F.; Glenn, A.W.; Bulmer, D.; Ward, T.E.

    1990-01-01

    There is increasing interest in the use of microorganisms to recover metals from ores, as well as to remove sulfur from coal. These so-called bioleaching processes are mediated by a number of bacteria. The best-studied of these organisms are acidophiles including Thiobacillus and Acidiphilium species. Our laboratory has focused on developing genetic strategies to allow the manipulation of acidophilic bacteria to improve and augment their utility in large scale operations. We have recently been successful in employing conjugation for interbacterial transfer of genetic information, as well as in directly transforming Acidiphilium by use of electroporation. We are now testing the properties of IncPl, IncW and IncQ plasmid vectors in Acidiphilium to determine their relative usefulness in routine manipulation of acidophiles and transfer between organisms. This study also allows us to determine the natural ability of these bacteria to transfer genetic material amongst themselves in their particular environment. 21 refs., 3 figs., 2 tabs.

  7. Bacteria, Yeast and Chemicals on Human Skin

    Medline Plus

    Full Text Available ... Videos & Tools You Are Here: Home ? Latest Health News ? Bacteria, Yeast and Chemicals on Human Skin URL ... page: http://www.nlm.nih.gov/medlineplus/videos/news/Microbes_040115-1.html Bacteria, Yeast and Chemicals ...

  8. Bacteria, Yeast and Chemicals on Human Skin

    Science.gov (United States)

    ... medlineplus/videos/news/Microbes_040115-1.html Bacteria, Yeast and Chemicals on Human Skin HealthDay News Video - ... this page, please enable JavaScript. Play video: Bacteria, Yeast and Chemicals on Human Skin For closed captioning, ...

  9. Re-engineering bacteria for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Antimicrobial activity and Characterization of Marine bacteria

    OpenAIRE

    Jeganathan, P.; Rajasekaran, K. M.; Asha Devi, N. K.; Karuppusamy, S.

    2013-01-01

    Marine bacteria were isolated from seawater was collected from different coastal areas of the Tamilnadu Sea. The antimicrobial activities of these bacteria were investigated. Ethyl acetate extracts of marine bacterial fermentation were screened for antimicrobial activities using the method of agar diffusion. The results showed that 25 strains of the isolates have antimicrobial activity. The proportion of active bacteria associated with isolated from seawater. The active marine bacteria were a...

  11. 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 ...

  12. 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…

  13. Magnetotactic bacteria at the geomagnetic equator

    International Nuclear Information System (INIS)

    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)

  14. Thermophilic spore-forming bacteria isolated from spoiled canned food and their heat resistance. Results of a French ten-year survey.

    Science.gov (United States)

    André, S; Zuber, F; Remize, F

    2013-07-15

    Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. LACF are also often submitted to additional incubation conditions, typically 55 °C for 7 days, to monitor spoilage by thermophiles. In this study we identified the bacterial species responsible for non-stability after prolonged at 55 °C of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). A single species was identified for 93% of examined samples. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Species frequency was dependent on food category, i.e. vegetables, ready-made meals containing meat, seafood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these food categories. The spore heat resistance parameters (D or ? and z values) from 36 strains isolated in this study were determined. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. This extensively-documented survey of the species that cause non-stability at 55 °C in LACF will help canneries to improve the management of microbial contamination. PMID:23728430

  15. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  16. Dissipative Shocks behind Bacteria Gliding

    CERN Document Server

    Virga, Epifanio G

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.

  17. Aggregation Patterns in Stressed Bacteria

    CERN Document Server

    Tsimring, L S; Aranson, I S; Ben-Jacob, E; Cohen, I; Shochet, O; Tsimring, Lev; Levine, Herbert; Aranson, Igor; Ben-Jacob, Eshel; Cohen, Inon; Shochet, Ofer

    1995-01-01

    We study the formation of spot patterns seen in a variety of bacterial species when the bacteria are subjected to oxidative stress due to hazardous byproducts of respiration. Our approach consists of coupling the cell density field to a chemoattractant concentration as well as to nutrient and waste fields. The latter serves as a triggering field for emission of chemoattractant. Important elements in the proposed model include the propagation of a front of motile bacteria radially outward form an initial site, a Turing instability of the uniformly dense state and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is explained as being due the variation of the details of the initiation of the chemoattractant emission as well as the transition to a non-motile phase.

  18. Bacteria Allocation Using Monte Carlo

    Science.gov (United States)

    Hill, David R.

    This applet, created by David Hill and Lila Roberts, uses the Monte Carlo technique to simulate a count of bacteria that are present as a result of a certain sampling process. This simulation could be modified to perform other experiments. This experiment is geared towards high school calculus students or probability courses for mathematics majors in college. Students must possess a basic understanding of probability concepts before performing this experiment. Overall, it is a nice activity for a mathematics classroom.

  19. Lima Bean Bacteria DNA Extraction

    Science.gov (United States)

    Lana Hays

    2009-01-01

    This laboratory exercise is designed to show learners how DNA can easily be extracted from lima bean bacteria. This experiment requires the use of a centrifuge (not included in cost of materials). Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

  20. F-LE Bacteria Populations

    Science.gov (United States)

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A hospital is conducting a study to see how different environmental conditions influence the growth of streptococcus pneumonia, one of the bacteria whi...

  1. Box-shaped halophilic bacteria.

    OpenAIRE

    Javor, B; Requadt, C; Stoeckenius, W

    1982-01-01

    Three morphologically similar strains of halophilic, box-shaped procaryotes have been isolated from brines collected in the Sinai, Baja California (Mexico), and southern California (United States). Although the isolates in their morphology resemble Walsby's square bacteria, which are a dominant morphological type in the Red Sea and Baja California brines, they are probably not identical to them. The cells show the general characteristics of extreme halophiles and archaebacteria. They contain ...

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

    OpenAIRE

    SteveJCharette

    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...

  3. Chemical signature of magnetotactic bacteria.

    Science.gov (United States)

    Amor, Matthieu; Busigny, Vincent; Durand-Dubief, Mickaël; Tharaud, Mickaël; Ona-Nguema, Georges; Gélabert, Alexandre; Alphandéry, Edouard; Menguy, Nicolas; Benedetti, Marc F; Chebbi, Imène; Guyot, François

    2015-02-10

    There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record. PMID:25624469

  4. 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 mycoplasma and CWD bacteria is difficult at best and cites Pachas's 1985 study wherein one mycoplasma was actually mistaken for a CWD form of a bacterium closely related to the mycobacteria. It is important to realize that the statement "HIV is the sole cause of AIDS" is just a hypothesis. There are unanswered questions and controversy concerning the role of HIV "as the sole cause of AIDS." And until they are resolved, a cure is not possible. This paper explores the possible role of acid-fast tuberculous mycobacteria as "primary agents" in AIDS. PMID:18691828

  5. Recombinant Glycans on an S-Layer Self-Assembly Protein: A New Dimension for Nanopatterned Biomaterials

    OpenAIRE

    Steiner, Kerstin; Hanreich, Angelika; Kainz, Birgit; Hitchen, Paul G; Anne; Messner, Paul; Schäffer, Christina

    2008-01-01

    Crucial biological phenomena are mediated through carbohydrates that are displayed in a defined manner and interact with molecular scale precision. We lay the groundwork for the integration of recombinant carbohydrates into a “biomolecular construction kit” for the design of new biomaterials, by utilizing the self-assembly system of the crystalline cell surface (S)-layer protein SgsE of Geobacillus stearothermophilus NRS 2004/3a. SgsE is a naturally O-glycosylated protein, with intrinsic prop...

  6. Probabilistic exposure assessment model to estimate aseptic-UHT product failure rate.

    Science.gov (United States)

    Pujol, Laure; Albert, Isabelle; Magras, Catherine; Johnson, Nicholas Brian; Membré, Jeanne-Marie

    2015-01-01

    Aseptic-Ultra-High-Temperature (UHT) products are manufactured to be free of microorganisms capable of growing in the food at normal non-refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. Two important phases within the process are widely recognised as critical in controlling microbial contamination: the sterilisation steps and the following aseptic steps. Of the microbial hazards, the pathogen spore formers Clostridium botulinum and Bacillus cereus are deemed the most pertinent to be controlled. In addition, due to a relatively high thermal resistance, Geobacillus stearothermophilus spores are considered a concern for spoilage of low acid aseptic-UHT products. A probabilistic exposure assessment model has been developed in order to assess the aseptic-UHT product failure rate associated with these three bacteria. It was a Modular Process Risk Model, based on nine modules. They described: i) the microbial contamination introduced by the raw materials, either from the product (i.e. milk, cocoa and dextrose powders and water) or the packaging (i.e. bottle and sealing component), ii) the sterilisation processes, of either the product or the packaging material, iii) the possible recontamination during subsequent processing of both product and packaging. The Sterility Failure Rate (SFR) was defined as the sum of bottles contaminated for each batch, divided by the total number of bottles produced per process line run (10(6) batches simulated per process line). The SFR associated with the three bacteria was estimated at the last step of the process (i.e. after Module 9) but also after each module, allowing for the identification of modules, and responsible contamination pathways, with higher or lower intermediate SFR. The model contained 42 controlled settings associated with factory environment, process line or product formulation, and more than 55 probabilistic inputs corresponding to inputs with variability conditional to a mean uncertainty. It was developed in @Risk and run through Monte Carlo simulations. Overall, the highest SFR was associated with G. stearothermophilus (380000 bottles contaminated in 10(11) bottles produced) and the lowest to C. botulinum (3 bottles contaminated in 10(11) bottles produced). Unsurprisingly, SFR due to G. stearothermophilus was due to its ability to survive the UHT treatment. More interestingly, it was identified that SFR due to B. cereus (17000 bottles contaminated in 10(11) bottles produced) was due to an airborne recontamination of the aseptic tank (49%) and a post-sterilisation packaging contamination (33%). A deeper analysis (sensitivity and scenario analyses) was done to investigate how the SFR due to B. cereus could be reduced by changing the process settings related to potential air recontamination source. PMID:25440556

  7. Endophytic bacteria in Coffea arabica L.

    Science.gov (United States)

    Vega, Fernando E; Pava-Ripoll, Monica; Posada, Francisco; Buyer, Jeffrey S

    2005-01-01

    Eighty-seven culturable endophytic bacterial isolates in 19 genera were obtained from coffee plants collected in Colombia (n = 67), Hawaii (n = 17), and Mexico (n = 3). Both Gram positive and Gram negative bacteria were isolated, with a greater percentage (68%) being Gram negative. Tissues yielding bacterial endophytes included adult plant leaves, various parts of the berry (e.g., crown, pulp, peduncle and seed), and leaves, stems, and roots of seedlings. Some of the bacteria also occurred as epiphytes. The highest number of bacteria among the berry tissues sampled was isolated from the seed, and includes Bacillus , Burkholderia , Clavibacter , Curtobacterium , Escherichia , Micrococcus , Pantoea , Pseudomonas , Serratia , and Stenotrophomonas . This is the first survey of the endophytic bacteria diversity in various coffee tissues, and the first study reporting endophytic bacteria in coffee seeds. The possible role for these bacteria in the biology of the coffee plant remains unknown. PMID:16187260

  8. Medicinal smoke reduces airborne bacteria.

    Science.gov (United States)

    Nautiyal, Chandra Shekhar; Chauhan, Puneet Singh; Nene, Yeshwant Laxman

    2007-12-01

    This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the Biolog microplate panels and Microlog database. We have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24h in the closed room. Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacterium flaccumfaciens, Enterobacter aerogenes (Klebsiella mobilis), Kocuria rosea, Pseudomonas syringae pv. persicae, Staphylococcus lentus, and Xanthomonas campestris pv. tardicrescens in the open room even after 30 days is indicative of the bactericidal potential of the medicinal smoke treatment. We have demonstrated that using medicinal smoke it is possible to completely eliminate diverse plant and human pathogenic bacteria of the air within confined space. PMID:17913417

  9. Transformation of gram positive bacteria by sonoporation

    Energy Technology Data Exchange (ETDEWEB)

    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. Beneficial interactions between insects and gut bacteria

    OpenAIRE

    Rajagopal, R.

    2009-01-01

    Insects are amongst the most successful of animals, both in terms of diversity and in colonizing all ecological niches. Recent studies have highlighted the benefi ciary roles that bacteria play in the success and establishment of insects. By adopting techniques like 16S rRNA sequencing we are now in a position to understand the diversity of bacteria present in insect guts. It has been shown that some of these bacteria, like Wolbachia and Cardinium are involved in manipulating insect populatio...

  11. Molecular Communication Between Two Populations of Bacteria

    OpenAIRE

    Einolghozati, Arash; Sardari, Mohsen; Fekr, Faramarz

    2012-01-01

    Molecular communication is an expanding body of research. Recent advances in biology have encouraged using genetically engineered bacteria as the main component in the molecular communication. This has stimulated a new line of research that attempts to study molecular communication among bacteria from an information-theoretic point of view. Due to high randomness in the individual behavior of the bacterium, reliable communication between two bacteria is almost impossible. Th...

  12. Coryneform bacteria associated with canine otitis externa

    DEFF Research Database (Denmark)

    Aalbæk, Bent; Bemis, David A.

    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 bacteria, mainly Staphylococcus pseudintermedius alone (n=5) or in combination with Malassezia pachydermatis (n=5). Some coryneform isolates displayed resistance to fusidic acid or enrofloxacin, two antimicrobial agents commonly used for the treatment of otitis externa in dogs. The frequency of isolation of coryneform bacteria was 16% among 55 cases of canine otitis externa examined at the Danish hospital during 2007. In contrast, detectable levels of coryneform bacteria were not demonstrated in samples from the acustic meatus of 35 dogs with apparently healthy ears, attending the hospital during the same year. On basis of the current knowledge, these coryneform bacteria should be regarded as potential secondary pathogens able to proliferate in the environment of an inflamed ear canal.

  13. Coryneform bacteria associated with canine otitis externa.

    Science.gov (United States)

    Aalbæk, Bent; Bemis, David A; Schjærff, Mette; Kania, Stephen A; Frank, Linda A; Guardabassi, Luca

    2010-10-26

    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 bacteria, mainly Staphylococcus pseudintermedius alone (n=5) or in combination with Malassezia pachydermatis (n=5). Some coryneform isolates displayed resistance to fusidic acid or enrofloxacin, two antimicrobial agents commonly used for the treatment of otitis externa in dogs. The frequency of isolation of coryneform bacteria was 16% among 55 cases of canine otitis externa examined at the Danish hospital during 2007. In contrast, detectable levels of coryneform bacteria were not demonstrated in samples from the acustic meatus of 35 dogs with apparently healthy ears, attending the hospital during the same year. On basis of the current knowledge, these coryneform bacteria should be regarded as potential secondary pathogens able to proliferate in the environment of an inflamed ear canal. PMID:20434850

  14. Spectroscopic diagnostics for bacteria in biologic sample

    Science.gov (United States)

    El-Sayed, Mostafa A. (Atlanta, GA); El-Sayed, Ivan H. (Somerville, MA)

    2002-01-01

    A method to analyze and diagnose specific bacteria in a biologic sample using spectroscopy is disclosed. The method includes obtaining the spectra of a biologic sample of a non-infected patient for use as a reference, subtracting the reference from the spectra of an infected sample, and comparing the fingerprint regions of the resulting differential spectrum with reference spectra of bacteria in saline. Using this diagnostic technique, specific bacteria can be identified sooner and without culturing, bacteria-specific antibiotics can be prescribed sooner, resulting in decreased likelihood of antibiotic resistance and an overall reduction of medical costs.

  15. Antibiotic-resistant bacteria in drinking water.

    OpenAIRE

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

    1981-01-01

    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 stan...

  16. Bacterias, fuente de energía para el futuro

    Directory of Open Access Journals (Sweden)

    Alba Ayde Romero Mejía

    2012-06-01

    Full Text Available This paper presents a family of bacteria called Geobacter that have the ability to produce power as a renewable source in a microbial fuel cell. These bacteria can completely oxidize organic compounds using different elements or substances as electron acceptors. The paper addresses key features of the bacteria, the mechanisms used to harness the electricity generated and an approximation of the system required to become a competitive source of renewable energy. The results show a comparative analysis of sources of conventional and unconventional energy with respect to the Geobacter family of bacteria.

  17. MICROBIOLOGY: How Bacteria Change Gear

    Science.gov (United States)

    Richard M. Berry (University of Oxford; Department of Physics, Clarendon Lab)

    2008-06-20

    Access to the article is free, however registration and sign-in are required. Many species of bacteria form biofilms, slimy carpets a fraction of a millimeter thick that appear on rocks, leaves, pipes, teeth--pretty much any place that has a supply of nutrients and water. Cells must first attach to a surface, which in many species requires swimming propelled by rotating helical flagella (1). Two things typically happen next. Cells stop expressing genes that encode components of the flagellum, and they secrete a sticky matrix of polysaccharides that holds them together on the surface (2). Once at a surface, swimming may be a hindrance rather than a help, and an inverse relationship between swimming and attachment has been seen in many diverse species (3). Bacterial motility is arrested when a protein that acts as a clutch disables rotation of the flagellar motor.

  18. Aggregation Patterns in Stressed Bacteria

    International Nuclear Information System (INIS)

    We study the formation of spot patterns seen in bacterial colonies when the bacteria are subjected to oxidative stress due to hazardous by-products of respiration. The cell density is coupled to a chemoattractant concentration as well as to nutrient and waste fields. The model combines the propagation of a front of motile bacterial radially outward from an initial site, a Turing instability of the uniformly dense state, and a reduction of motility for cells sufficiently far behind the front. The wide variety of patterns seen in the experiments is reproduced by the model by varying the details of the initiation of the chemoattractant emission as well as the transition to a nonmotile phase

  19. Prevalence of Clostridium botulinum and thermophilic heat-resistant spores in raw carrots and green beans used in French canning industry.

    Science.gov (United States)

    Sevenier, V; Delannoy, S; André, S; Fach, P; Remize, F

    2012-04-16

    Two categories of vegetables (carrots and green beans) that are widely used in the manufacture of canned food were surveyed for their spore contamination. Samples were recovered from 10 manufactures spread over all producing areas in France. Two samples over 316 raw vegetables collected were found positive for botulinum neurotoxin producing Clostridia spores as tested by PCR-based GeneDisc assay. Both positive samplestested positive for the type B neurotoxin gene (bont/B). In parallel, heat-resistant spores of thermophilic bacteria that are likely to be associated with canned food spoilage after prolonged incubation at 55 °C were surveyed after specific enrichment. Prevalence varied between 1.6% for Moorella thermoacetica/thermoautotrophica in green bean samples and 8.6% for either Geobacillus stearothermophilus or Thermoanaerobacterium spp. in carrot samples. Vegetable preparation, e.g. washing and edge cutting, considerably reduced spore contamination levels. These data constitute the first wide examination of vegetables specifically cultivated for industrialpurposes for their contamination by spores of thermophilic bacterial species. PMID:22405945

  20. Bacteria, Yeast and Chemicals on Human Skin

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  1. An overview of lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Department of Applied Chemistry, Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM, 40450 Shah Alam, Selangor, Malaysia

    2011-06-01

    Full Text Available Lactic acid bacteria (LAB are renowned for the potential of producing antimicrobial compound and other value added products. Undeniable to concern these probiotic has contributed to the importance of human life. Deserving an attention for its capabilities, this paper will discuss on the general description of lactic acid bacteria, genetics, metabolism and its application to the industries.

  2. Bacteria, Yeast and Chemicals on Human Skin

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  3. Bacteria, Yeast and Chemicals on Human Skin

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  4. Bacteria, Yeast and Chemicals on Human Skin

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  5. Intracellular bacteria find the right motion.

    Science.gov (United States)

    Gouin, Edith; Torres, Juan-Jose Quereda; Cossart, Pascale

    2015-04-01

    Benanti et al. report that Burkholderia pseudomallei and Burkholderia mallei bacteria express proteins that mimic Ena/Vasp family proteins to polymerize actin, thereby inducing actin-based motility. Thus, bacteria can use the various cellular actin polymerization mechanisms for intra- and inter-cellular dissemination. PMID:25860603

  6. Chemotactic selection of pollutant degrading soil bacteria

    Science.gov (United States)

    Hazen, T.C.

    1991-03-04

    A method is described for identifying soil microbial strains which may be bacterial degraders of pollutants. This method includes: Placing a concentration of a pollutant in a substantially closed container; placing the container in a sample of soil for a period of time ranging from one minute to several hours; retrieving the container and collecting its contents; microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to innoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  7. Antimicrobial activity and Characterization of Marine bacteria

    Directory of Open Access Journals (Sweden)

    P.Jeganathan*

    2013-12-01

    Full Text Available Marine bacteria were isolated from seawater was collected from different coastal areas of the Tamilnadu Sea. The antimicrobial activities of these bacteria were investigated. Ethyl acetate extracts of marine bacterial fermentation were screened for antimicrobial activities using the method of agar diffusion. The results showed that 25 strains of the isolates have antimicrobial activity. The proportion of active bacteria associated with isolated from seawater. The active marine bacteria were assigned to the genera Alteromonas, Pseudomonas, Bacillus and Marinobacter. The TLC autobiographic overlay assay implied that the antimicrobial metabolites produced by four strains with wide antimicrobial spectrum were different. These marine bacteria were expected to be potential resources of natural antibiotic products. It can be concluded that isolation of Marine bacterial samples can offer a numbers of microbial strains for sources of new biomolecules from Marine sources.

  8. Filamentous bacteria existence in aerobic granular reactors.

    Science.gov (United States)

    Figueroa, M; Val Del Río, A; Campos, J L; Méndez, R; Mosquera-Corral, A

    2015-05-01

    Filamentous bacteria are associated to biomass settling problems in wastewater treatment plants. In systems based on aerobic granular biomass they have been proposed to contribute to the initial biomass aggregation process. However, their development on mature aerobic granular systems has not been sufficiently studied. In the present research work, filamentous bacteria were studied for the first time after long-term operation (up to 300 days) of aerobic granular systems. Chloroflexi and Sphaerotilus natans have been observed in a reactor fed with synthetic wastewater. These filamentous bacteria could only come from the inoculated sludge. Thiothrix and Chloroflexi bacteria were observed in aerobic granular biomass treating wastewater from a fish canning industry. Meganema perideroedes was detected in a reactor treating wastewater from a plant processing marine products. As a conclusion, the source of filamentous bacteria in these mature aerobic granular systems fed with industrial effluents was the incoming wastewater. PMID:25533039

  9. Chryseobacterium indologenes, novel mannanase-producing bacteria

    Directory of Open Access Journals (Sweden)

    Surachai Rattanasuk

    2009-10-01

    Full Text Available Mannanase is a mannan degrading enzyme which is produced by microorganisms, including bacteria. This enzyme can be used in many industrial processes as well as for improving the quality of animal feeds. The aim of the present study was toscreen and characterize the mannanase-producing bacteria. Two genera of bacteria were isolated from Thai soil samples,fermented coconut, and fertilizer. Screening was carried out on agar plates containing mannan stained with iodine solution.The bacteria were identified by partial 16S rRNA gene sequence, biochemical test and morphology, respectively. The mannanase activity was determined by zymogram and DNS method. Two strains of bacteria with mannanase activity were identified as Bacillus and Chryseobacterium. This is the first report of mannanase-producing Chryseobacterium.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    SteveJCharette

    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.

  12. Stop the Spread of Superbugs: Help Fight Drug Resistant Bacteria

    Science.gov (United States)

    ... the Spread of Superbugs Help Fight Drug-Resistant Bacteria For nearly a century, bacteria-fighting drugs known as antibiotics have helped to control and destroy many of the harmful bacteria that can make us sick. But in recent ...

  13. Birefringence Determination of Magnetic Moments of Magnetotactic Bacteria

    OpenAIRE

    Rosenblatt, Charles; de Araujo, F. Flavio Torres; Frankel, Richard B.

    1982-01-01

    A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.

  14. 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.

  15. Motility fractionation of bacteria by centrifugation

    Science.gov (United States)

    Maggi, Claudio; Lepore, Alessia; Solari, Jacopo; Rizzo, Alessandro; Di Leonardo, Roberto

    Centrifugation is a widespread laboratory technique used to separate mixtures into fractions characterized by a specific size, weight or density. We demonstrate that centrifugation can be also used to separate swimming cells having different motility. To do this we study self-propelled bacteria under the influence of an external centrifugal field. Using dynamic image correlation spectroscopy we measure the spatially resolved motility of bacteria after centrifugation. A significant gradient in swimming-speeds is observed for increasing centrifugal speeds. Our results can be reproduced by a model that treats bacteria as "hot" colloidal particles having a diffusion coefficient that depends on the swimming speed.

  16. Protection of probiotic bacteria in synbiotic matrices

    Science.gov (United States)

    Probiotics, like Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium breve, Bifidobacterium longum, when encapsulated with prebiotic fibers such as fructo-oligosaccharides (FOS), inulin (I) and pectic-oligosaccharides (POS), formed a synbiotic matrix system that protected the bacteria ...

  17. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.

    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 and particularly higher organisms, covering a variety of functions ranging from pathogenic to symbiotic interactions. The detailed knowledge of these bacterial communication systems has opened completely new perspectives for controlling undesired microbial activities.

  18. Bacteria, Yeast and Chemicals on Human Skin

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  19. Bacteria, Yeast and Chemicals on Human Skin

    Medline Plus

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  20. 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.

  1. Mixed Messages: How Bacteria Resolve Conflicting Signals

    OpenAIRE

    Young, Jonathan W.; Elowitz, Michael B.

    2011-01-01

    An elegant new study by Bollenbach and Kishony (2011) in this issue of Molecular Cell shows how bacteria resolve the apparent conflicts created when they face two signals with opposite effects on gene expression.

  2. Effect of leukocyte hydrolases on bacteria

    International Nuclear Information System (INIS)

    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

  3. Magnetotactic Bacteria from Extreme Environments

    Directory of Open Access Journals (Sweden)

    Christopher T. Lefèvre

    2013-03-01

    Full Text Available Magnetotactic bacteria (MTB represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4 or greigite (Fe3S4 and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  4. Magnetotactic Bacteria from Extreme Environments

    Science.gov (United States)

    Bazylinski, Dennis A.; Lefère, Christopher T.

    2013-03-01

    Magnetotactic bacteria (MTB) represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4) or greigite (Fe3S4) and cause cells to align along the Earth's geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic-anoxic interface (OAI) in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

  5. Folate Production by Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    Stefano Raimondi

    2011-01-01

    Full Text Available Probiotic bacteria, mostly belonging to the genera Lactobacillus and Bifidobacterium, confer a number of health benefits to the host, including vitamin production. With the aim to produce folate-enriched fermented products and/or develop probiotic supplements that accomplish folate biosynthesis in vivo within the colon, bifidobacteria and lactobacilli have been extensively studied for their capability to produce this vitamin. On the basis of physiological studies and genome analysis, wild-type lactobacilli cannot synthesize folate, generally require it for growth, and provide a negative contribution to folate levels in fermented dairy products. Lactobacillus plantarum constitutes an exception among lactobacilli, since it is capable of folate production in presence of para-aminobenzoic acid (pABA and deserves to be used in animal trials to validate its ability to produce the vitamin in vivo. On the other hand, several folate-producing strains have been selected within the genus Bifidobacterium, with a great variability in the extent of vitamin released in the medium. Most of them belong to the species B. adolescentis and B. pseudocatenulatum, but few folate producing strains are found in the other species as well. Rats fed a probiotic formulation of folate-producing bifidobacteria exhibited increased plasma folate level, confirming that the vitamin is produced in vivo and absorbed. In a human trial, the same supplement raised folate concentration in feces. The use of folate-producing probiotic strains can be regarded as a new perspective in the specific use of probiotics. They could more efficiently confer protection against inflammation and cancer, both exerting the beneficial effects of probiotics and preventing the folate deficiency that is associated with premalignant changes in the colonic epithelia.

  6. Comparative cytotoxicity of periodontal bacteria

    International Nuclear Information System (INIS)

    The direct cytotoxicity of sonic extracts (SE) from nine periodontal bacteria for human gingival fibroblasts (HGF) was compared. Equivalent dosages (in terms of protein concentration) of SE were used to challenge HGF cultures. The cytotoxic potential of each SE was assessed by its ability to (1) inhibit HGF proliferation, as measured by direct cell counts; (2) inhibit 3H-thymidine incorporation in HGF cultures; or (3) cause morphological alterations of the cells in challenged cultures. The highest concentration (500 micrograms SE protein/ml) of any of the SEs used to challenge the cells was found to be markedly inhibitory to the HGFs by all three of the criteria of cytotoxicity. At the lowest dosage tested (50 micrograms SE protein/ml); only SE from Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Fusobacterium nucleatum caused a significant effect (greater than 90% inhibition or overt morphological abnormalities) in the HGFs as determined by any of the criteria employed. SE from Capnocytophaga sputigena, Eikenella corrodens, or Wolinella recta also inhibited cell proliferation and thymidine incorporation at this dosage; however, the degree of inhibition (5-50%) was consistently, clearly less than that of the first group of three organisms named above. The SE of the three other organisms tested (Actinomyces odontolyticus, Bacteroides intermedius, and Streptococcus sanguis) had little or no effect (0-10% inhibition) at this concentration. The data suggtion) at this concentration. The data suggest that the outcome of the interaction between bacterial components and normal resident cells of the periodontium is, at least in part, a function of the bacterial species

  7. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  8. Distribution of coliform bacteria in waste water

    OpenAIRE

    Chandan Kumar Bahura; Dau Lal Bohra; Vikas Modasiya

    2012-01-01

    Biological activity of water can be apparently judged by the colonization of bacteria (microbes). In order to find out the extent of pollution and the relationship between inorganic matters and microbiota, a quantitative and qualitative analysis of bacteria in various types of sewage waters, namely sewage water by the residential colonies (group I), industrial waste water (group II), sewage treatment hub (group III), unorganized collected waste water (group IV) and old residential waste colle...

  9. Molecular approaches to study probiotic bacteria

    OpenAIRE

    Vaughan, E. E.; Heilig, G. H. J.; Zoetendal, E. G.; Satokari, R.; Collins, J. K.; Akkermans, A. D. L.; Vos, W. M.

    2000-01-01

    Functional foods comprising probiotic bacteria are receiving increasing attention from the scientific community and science funding agencies [1]. An essential aspect relating to the functionality of probiotic-based foods is to develop molecular methods to determine the presence, activity and viability of probiotic bacteria in the human gastrointestinal (GI) tract [2]. The GI tract is composed of a complex ecosystem of various microbial habitats colonized by numerous different commensal micro-...

  10. Probiotic Lactic Acid Bacteria: A Review

    OpenAIRE

    Quinto, Emiliano J; Pilar Jiménez; Irma Caro; Jesús Tejero; Javier Mateo; Tomás Girbés

    2014-01-01

    Lactic acid bacteria (LAB) play a critical role in food production and health maintenance. There is an increasing interest in these species to reveal the many possible health benefits associated with them. The actions of LAB are species and strain specific, and depend on the amount of bacteria available in the gastrointestinal tract. Consumers are very concerned of chemical preservatives and processed foods. However, products with or processed with LAB are accepted as a natural way to preserv...

  11. Visualizing Bacteria in Nematodes using Fluorescent Microscopy

    OpenAIRE

    Murfin, Kristen E.; Chaston, John; Goodrich-blair, Heidi

    2012-01-01

    Symbioses, the living together of two or more organisms, are widespread throughout all kingdoms of life. As two of the most ubiquitous organisms on earth, nematodes and bacteria form a wide array of symbiotic associations that range from beneficial to pathogenic 1-3. One such association is the mutually beneficial relationship between Xenorhabdus bacteria and Steinernema nematodes, which has emerged as a model system of symbiosis 4. Steinernema nematodes are entomopathogenic, using their bact...

  12. Characterization of (per)chlorate-reducing bacteria

    OpenAIRE

    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 belonging to the species Pseudomonas chloritidismutans and a (per)chlorate-reducing strain Dechloromonas hortensis were isolated. The characterization of the chlorate-reducing strain AW-1, which was isolated from a bioreactor ...

  13. Biotechnology Curriculum Freshman Exploratory: Growing Bacteria

    Science.gov (United States)

    Kurtz, Mary Jane

    Bacteria are everywhere in the environment. To prove this in this activity, students will take samples of different surfaces around the classroom, and nearby places, as well as their own fingers. To detect bacteria, students will need to provide food for them to grow on. Students will be using the nutrient agar plates that have already been prepared. This lesson plan document may be downloaded in Microsoft Word file format.

  14. Investigating the Uses of Backyard Bacteria

    Science.gov (United States)

    Elisa Brako

    2009-01-01

    The purpose of this lab is to recognize that the answers to some of society's industrial challenges may lie right in our own backyards. Learners discover how to select protein-digesting bacteria from various soil samples. After isolating the colonies, learners are then encouraged to investigate ways to test the effectiveness of their specimens in breaking down protein stains on clothing. This activity demonstrates how bacteria with specific enzymatic capabilities can be isolated with a simple microbiology technique. Adult supervision recommended.

  15. Polyamine Effects on Antibiotic Susceptibility in Bacteria?

    OpenAIRE

    Kwon, Dong-Hyeon; Lu, Chung-Dar

    2007-01-01

    Biogenic polyamines (e.g., spermidine and spermine) are a group of essential polycationic compounds found in all living cells. The effects of spermine and spermidine on antibiotic susceptibility were examined with gram-negative Escherichia coli and Salmonella enterica serovar Typhimurium bacteria and clinical isolates of Pseudomonas aeruginosa and with gram-positive Staphylococcus aureus bacteria, including methicillin-resistant S. aureus (MRSA). Exogenous spermine exerted a dose-dependent in...

  16. Recovery of pathogenic bacteria from cerebrospinal fluid.

    OpenAIRE

    Murray, P. R.; Hampton, C M

    1980-01-01

    We studied the conditions necessary for optimal recovery of bacteria from cerebrospinal fluid. Our results indicated that Streptopcoccus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae can be quantitatively recovered in the sediment after centrifugation at 1,500 X g for 15 min. Equivalent numbers of bacteria were recovered by centrifugation or filtration of antibiotic-free cerebrospinal fluid; however, bacterial recovery by filtration was less effective with antibiotic-suppleme...

  17. Motility fractionation of bacteria by centrifugation

    OpenAIRE

    C. Maggi; Lepore, A.; J. Solari; Rizzo, A.; Di Leonardo, R.

    2013-01-01

    Centrifugation is a widespread laboratory technique used to separate mixtures into fractions characterized by a specific size, weight or density. We demonstrate that centrifugation can be also used to separate swimming cells having different motility. To do this we study self-propelled bacteria under the influence of an external centrifugal field. Using dynamic image correlation spectroscopy we measure the spatially resolved motility of bacteria after centrifugation. A signi...

  18. Low-temperature sensors in bacteria.

    OpenAIRE

    Eriksson, Sofia; Hurme, Reini; Rhen, Mikael

    2002-01-01

    Bacteria are ubiquitous colonizers of various environments and host organisms, and they are therefore often subjected to drastic temperature alterations. Temperature alterations set demands on these colonizers, in that the bacteria need to readjust their biochemical constitution and physiology in order to survive and resume growth at the new temperature. Furthermore, temperature alteration is also a main factor determining the expression or repression of bacterial virulence functions. To cope...

  19. Facultatively oligotrophic bacteria in Roman mural paintings

    OpenAIRE

    Laiz Trobajo, L.; Hermosín, Bernardo; Caballero, Belén; Sáiz-Jiménez, Cesáreo

    2002-01-01

    [EN]: Due to the limitation of nutrients during long periods, deteriorated monuments, and particularIy their walls, represent an interesting ecosystem where oligotrophic bacteria can be isolated. Therefore, facultatively oligotrophic bacteria, present in the deteriorated mural paintings decoratíng the Tomb of Servilia, Roman Necropolis of Carmona, 1st and 2nd century AD, were studied. The most abundant genera were Bacillus and Paenibacillus, which were also the most abundant copi...

  20. Competition for hydrogen by human faecal bacteria: evidence for the predominance of methane producing bacteria.

    OpenAIRE

    Strocchi, A.; Furne, J. K.; Ellis, C. J.; Levitt, M. D.

    1991-01-01

    Studies of sludge have shown that some species of sulphate reducing bacteria outcompete methane producing bacteria for the common substrate H2. A similar competition may exist in human faeces where the methane (CH4) producing status of an individual depends on the faecal concentration of sulphate reducing bacteria. To determine if non-methanogenic faeces outcompete CH4 producing faeces for H2, aliquots of each type of faeces were incubated alone or mixed together, with or without addition of ...

  1. Study of Lactobacillus as Probiotic Bacteria

    Directory of Open Access Journals (Sweden)

    J Nowroozi

    2004-07-01

    Full Text Available Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and concentrated cell free culture after treatment with ?-amylase, lysozyme and trypsin was determined. The isolated bacteria were Lacto. plantarum, Lacto delbruekii, Lacto. acidophilus, Lacto. brevis. The isolated bacteria had strong activity against indicator strains. The antibacterial activity was stable at 100ºC for 10 min and at 56ºC for 30 min, but activity was lost after autoclaving. The maximum production of plantaricin was obtained at 25 - 30ºC at pH 6.5. Because, lactobacilli that used to process sausage fermentation are producing antimicrobial activity with heat stability bacteriocin, so, these bacteria may be considered to be a healthy probiotic diet. Lactobacilli originally isolated from meat products are the best condidates as probiotic bacteria to improve the microbiological safety of these foods.

  2. Molecular probe technology detects bacteria without culture

    Directory of Open Access Journals (Sweden)

    Hyman Richard W

    2012-03-01

    Full Text Available Abstract Background Our ultimate goal is to detect the entire human microbiome, in health and in disease, in a single reaction tube, and employing only commercially available reagents. To that end, we adapted molecular inversion probes to detect bacteria using solely a massively multiplex molecular technology. This molecular probe technology does not require growth of the bacteria in culture. Rather, the molecular probe technology requires only a sequence of forty sequential bases unique to the genome of the bacterium of interest. In this communication, we report the first results of employing our molecular probes to detect bacteria in clinical samples. Results While the assay on Affymetrix GenFlex Tag16K arrays allows the multiplexing of the detection of the bacteria in each clinical sample, one Affymetrix GenFlex Tag16K array must be used for each clinical sample. To multiplex the clinical samples, we introduce a second, independent assay for the molecular probes employing Sequencing by Oligonucleotide Ligation and Detection. By adding one unique oligonucleotide barcode for each clinical sample, we combine the samples after processing, but before sequencing, and sequence them together. Conclusions Overall, we have employed 192 molecular probes representing 40 bacteria to detect the bacteria in twenty-one vaginal swabs as assessed by the Affymetrix GenFlex Tag16K assay and fourteen of those by the Sequencing by Oligonucleotide Ligation and Detection assay. The correlations among the assays were excellent.

  3. Bacteria motility at oil-water interfaces

    Science.gov (United States)

    Juarez, Gabriel; Smirga, Steven; Fernandez, Vicente; Stocker, Roman

    2012-11-01

    The swimming dynamics of bacteria are strongly influenced by interfaces: Motile bacteria often accumulate at rigid boundaries, such as liquid-solid interfaces, and at soft boundaries, such as liquid-air or liquid-liquid interfaces. Attachment of bacteria to these interfaces is crucial for the formation of biofilms (liquid-solid), pellicles (liquid-air), and oil-degrading communities (liquid-liquid). We investigated the motility of the oil-degrading bacteria Marinobacter aquaeolei in the presence of oil droplets. We created individual oil droplets using dedicated microfluidic devices and captured the swimming behavior of individual bacteria near the interface and their attachment dynamics to the droplets with high-speed and epifluorescent microscopy. We find that Marinobacter aquaeolei has a high affinity towards interfaces and their swimming dynamics at soft interfaces differ from both those in the bulk and at rigid boundaries. Characterizing the interaction and attachment of motile bacteria to liquid-liquid interfaces will promote a fundamental understanding to oil-microbe interactions in aquatic environments and potentially lead to improved oil bioremediation strategies.

  4. Nutritional Interdependence Among Rumen Bacteria During Cellulose Digestion In Vitro

    OpenAIRE

    Miura, Hideki; Horiguchi, Masaaki; Ogimoto, Keiji; Matsumoto, Tatsuro

    1983-01-01

    A study has been made of the promoting effect of starch on cellulose digestion by mixed rumen bacteria in a cellulose-urea medium. Starch supplementation of the medium promoted the growth of bacteria that required neither amino acids (AA) nor branched-chain fatty acids (BrFA). The growth of these bacteria was followed by the growth of AA-dependent bacteria, AA- or BrFA-dependent bacteria, BrFA-producing bacteria, and finally, BrFA-dependent cellulolytic bacteria. Population changes of these b...

  5. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    OpenAIRE

    André Horta; Susete Pinteus; Celso Alves; Nádia Fino; Joana Silva; Sara Fernandez; Américo Rodrigues; Rui Pedrosa

    2014-01-01

    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 act...

  6. Bacterias, fuente de energía para el futuro / Bacteria, source of energy for the future

    Scientific Electronic Library Online (English)

    Alba Ayde, Romero Mejía; Jorge Adrian, Vásquez; Armando, Lugo González.

    2012-04-01

    Full Text Available En el presente trabajo expone una familia de bacterias denominadas Geobacter que tienen la capacidad de producir energía eléctrica como fuente renovable en una celda de combustible microbiana. Estas bacterias pueden oxidar totalmente compuestos orgánicos empleando diferentes elementos o sustancias c [...] omo aceptores de electrones. El trabajo aborda características principales de la bacteria, como los mecanismos utilizados para aprovechar la electricidad que genera y una aproximación sobre el sistema requerido para convertirla en una fuente de energía renovable competitiva. Los resultados muestran un análisis comparativo de fuentes de energía convencionales y no convencionales con respecto a la familia de bacterias Geobacter. Abstract in english This paper presents a family of bacteria called Geobacter that have the ability to produce power as a renewable source in a microbial fuel cell. These bacteria can completely oxidize organic compounds using different elements or substances as electron acceptors. The paper addresses key features of t [...] he bacteria, the mechanisms used to harness the electricity generated and an approximation of the system required to become a competitive source of renewable energy. The results show a comparative analysis of sources of conventional and unconventional energy with respect to the Geobacter family of bacteria.

  7. 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.

  8. Bacteria dispersal by hitchhiking on zooplankton

    DEFF Research Database (Denmark)

    Grossart, Hans-Peter; Dziallas, Claudia

    2010-01-01

    Microorganisms and zooplankton are both important components of aquatic food webs. Although both inhabit the same environment, they are often regarded as separate functional units that are indirectly connected through nutrient cycling and trophic cascade. However, research on pathogenic and nonpathogenic bacteria has shown that direct association with zooplankton has significant influences on the bacteria's physiology and ecology. We used stratified migration columns to study vertical dispersal of hitchhiking bacteria through migrating zooplankton across a density gradient that was otherwise impenetrable for bacteria in both upward and downward directions (conveyor-belt hypothesis). The strength of our experiments is to permit quantitative estimation of transport and release of associated bacteria: vertical migration of Daphnia magna yielded an average dispersal rate of 1.3 x 10(5) x cells x Daphnia(-1) x migration cycle(-1) for the lake bacterium Brevundimonas sp. Bidirectional vertical dispersal by migrating D. magna was also shown for two other bacterial species, albeit at lower rates. The prediction that diurnally migrating zooplankton acquire different attached bacterial communities from hypolimnion and epilimnion between day and night was subsequently confirmed in our field study. In mesotrophic Lake Nehmitz, D. hyalina showed pronounced diel vertical migration along with significant diurnal changes in attached bacterial community composition. These results confirm that hitchhiking on migrating animals can be an important mechanism for rapidly relocating microorganisms, including pathogens, allowing them to access otherwise inaccessible resources.

  9. Bacteria and plutonium in marine environments

    International Nuclear Information System (INIS)

    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 237Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 104 to 105 cells/ml in seawater or 107 to 108 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 237Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistryemistry

  10. Diversity of endophytic bacteria in Brazilian sugarcane.

    Science.gov (United States)

    Magnani, G S; Didonet, C M; Cruz, L M; Picheth, C F; Pedrosa, F O; Souza, E M

    2010-01-01

    Endophytic bacteria live inside plant tissues without causing disease. Studies of endophytes in sugarcane have focused on the isolation of diazotrophic bacteria. We examined the diversity of endophytic bacteria in the internal tissues of sugarcane stems and leaves, using molecular and biochemical methods. Potato-agar medium was used to cultivate the endophytes; 32 isolates were selected for analysis. DNA was extracted and the 16S rRNA gene was partially sequenced and used for molecular identification. Gram staining, catalase and oxidase tests, and the API-20E system were used to characterize the isolates. The strains were divided into five groups, based on the 16S rRNA sequences. Group I comprised 14 representatives of the Enterobacteriaceae; group II was composed of Bacilli; group III contained one representative, Curtobacterium sp; group IV contained representatives of the Pseudomonadaceae family, and group V had one isolate with an uncultured bacterium. Four isolates were able to reduce acetylene to ethylene. Most of the bacteria isolated from the sugarcane stem and leaf tissues belonged to Enterobacteriaceae and Pseudomonaceae, respectively, demonstrating niche specificity. Overall, we found the endophytic bacteria in sugarcane to be more diverse than previously reported. PMID:20198580

  11. Biodegradation of 17?-ethinylestradiol by heterotrophic bacteria

    International Nuclear Information System (INIS)

    The presence of the synthetic estrogen 17?-ethinylestradiol (EE2) in the environment is of increasing concern due to the endocrine disruption of aquatic organisms. Incomplete removal from wastewater (WW) is one of the main sources of EE2 in aquatic ecosystems, thus improving processes like biological WW treatment/activated sludge (AS) is becoming significantly important. There are opposing results regarding EE2 biodegradability by AS; one discrepancy is the efficacy of heterotrophic bacteria. This research demonstrated the ability of heterotrophs commonly present in AS (B. subtilis, P. aeruginosa, P. putida, R. equi, R. erythropolis, R. rhodochrous, R. zopfii) to remove EE2. R. rhodochrous was the most successful with no detectable EE2 after 48 h; the other bacteria achieved 21%–61% EE2 removal. No additive or synergistic effects were observed due to the combination of the bacterial cultures with maximum EE2 removals of 43% after 300 h. - Highlights: ? Seven species of heterotrophic bacteria demonstrated the ability to degrade EE2. ? Rhodococcus species (especially R. rhodochrous) were the most successful. ? EE2 degradation by individual bacteria does not represent the capability of mixtures. ? Slight differences in bacterial mixture composition impact degradation trends. - Heterotrophic bacteria, especially Rhodococcus species, are capable of successfully degrading 17?-ethinylestradiol (EE2).

  12. The effects of ionizing radiation on bacteria

    International Nuclear Information System (INIS)

    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. (author)

  13. Bacteria?Triggered Release of Antimicrobial Agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Chiang, Wen?Chi

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase?sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof?of?concept of the responsive material is demonstrated by the bacteria?triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self?regulating system provides the basis for the development of device?relevant polymeric materials, which only release antibiotics in dependency of the titer of bacteria surrounding the medical device.

  14. Bacteria-Triggered Release of Antimicrobial Agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Chiang, Wen-Chi

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase?sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof?of?concept of the responsive material is demonstrated by the bacteria?triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self?regulating system provides the basis for the development of device?relevant polymeric materials, which only release antibiotics in dependency of the titer of bacteria surrounding the medical device.

  15. Bacteria-triggered release of antimicrobial agents

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V; Chiang, Wen-Chi

    2014-01-01

    Medical devices employed in healthcare practice are often susceptible to microbial contamination. Pathogenic bacteria may attach themselves to device surfaces of catheters or implants by formation of chemically complex biofilms, which may be the direct cause of device failure. Extracellular bacterial lipases are particularly abundant at sites of infection. Herein it is shown how active or proactive compounds attached to polymeric surfaces using lipase-sensitive linkages, such as fatty acid esters or anhydrides, may be released in response to infection. Proof-of-concept of the responsive material is demonstrated by the bacteria-triggered release of antibiotics to control bacterial populations and signaling molecules to modulate quorum sensing. The self-regulating system provides the basis for the development of device-relevant polymeric materials, which only release antibiotics in dependency of the titer of bacteria surrounding the medical device.

  16. Microgravity effects on pathogenicity of bacteria

    Directory of Open Access Journals (Sweden)

    Ya-juan WANG

    2013-01-01

    Full Text Available Microgravity is one of the important environmental conditions during spaceflight. A series of studies have shown that many kinds of bacteria could be detected in space station and space shuttle. Space environment or simulated microgravity may throw a certain influence on those opportunistic pathogens and lead to some changes on their virulence, biofilm formation and drug tolerance. The mechanism of bacteria response to space environment or simulated microgravity has not been defined. However, the conserved RNA-binding protein Hfq has been identified as a likely global regulator involved in the bacteria response to this environment. In addition, microgravity effects on bacterial pathogenicity may threaten astronauts' health. The present paper will focus on microgravity-induced alterations of pathogenicity and relative mechanism in various opportunistic pathogens.

  17. Chemotaxis When Bacteria Remember: Drift versus Diffusion

    CERN Document Server

    Chatterjee, Sakuntala; Kafri, Yariv

    2011-01-01

    Escherichia coli (E. coli) bacteria govern their trajectories by switching between running and tumbling modes as a function of the nutrient concentration they experienced in the past. At short time one observes a drift of the bacterial population, while at long time one observes accumulation in high-nutrient regions. Recent work has pointed to an apparent theoretical contradiction between drift toward favorable regions and accumulation in favorable regions. A number of such earlier studies assume that a bacterium resets its memory at tumbles -- a fact not borne out by experiment -- and make use of approximate coarse-grained descriptions. Here, we revisit the problem of chemotaxis without resorting to any memory resets. We find that when bacteria respond to the environment in a non-adaptive manner, chemotaxis is generally dominated by diffusion, whereas when bacteria respond in an adaptive manner, chemotaxis is dominated by a bias in the motion. In all cases, the apparent contradiction between favorable drift ...

  18. 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. PMID:9732040

  19. Flavones with antibacterial activity against cariogenic bacteria.

    Science.gov (United States)

    Sato, M; Fujiwara, S; Tsuchiya, H; Fujii, T; Iinuma, M; Tosa, H; Ohkawa, Y

    1996-11-01

    Methanolic extracts obtained from 13 plants were studied for their antibacterial activity against cariogenic bacteria. Among them, the extract from Artocarpus heterophyllus showed the most intensive activity. Serial chromatographic purifications offered two active compounds which were identified as 6-(3-methyl-1-butenyl)-5,2',4'-trihydroxy-3-isoprenyl-7-methoxy flavone and 5,7,2',4'-tetrahydroxy-6-isoprenylflavone. Both isolates completely inhibited the growth of primary cariogenic bacteria at 3.13-12.5 micrograms/ml. They also exhibited the growth inhibitory effects on plaque-forming streptococci. These phytochemical isoprenylflavones would be potent compounds for the prevention of dental caries. PMID:8953432

  20. Bacteria Provide Cleanup of Oil Spills, Wastewater

    Science.gov (United States)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Marshall Space Flight Center, Micro-Bac International Inc., of Round Rock, Texas, developed a phototrophic cell for water purification in space. Inside the cell: millions of photosynthetic bacteria. Micro-Bac proceeded to commercialize the bacterial formulation it developed for the SBIR project. The formulation is now used for the remediation of wastewater systems and waste from livestock farms and food manufacturers. Strains of the SBIR-derived bacteria also feature in microbial solutions that treat environmentally damaging oil spills, such as that resulting from the catastrophic 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico.

  1. Amplification of Signaling Events in Bacteria

    Science.gov (United States)

    Frederick W. Dahlquist (University of Oregon; Knight Professor and Head, Department of Chemistry, Member, Institute of Molecular Biology REV)

    2002-05-14

    Bacteria respond to extremely shallow chemical gradients by modifying their motility in a process called chemotaxis. This chemotactic response is characterized by high sensitivity to small concentration differences, which extends over a large range of concentrations. This combination of high signal gain and large dynamic range results from both a memory of past events and the ability to amplify small differences in signal between the memory and the current environment. Dahlquist describes the signaling mechanism used by bacteria to regulate the flagellar motor and the places in this pathway where signal amplification may occur.

  2. Bacterial biofilms. Bacteria Quorum sensing in biofilms

    Directory of Open Access Journals (Sweden)

    E. S. Vorobey

    2012-03-01

    Full Text Available Data on biofilms, their structure and properties, peculiarities of formation and interaction between microorganisms in the film are presented. Information on discovery and study of biofilms, importance of biofilms in the medical and clinical microbiology are offered. The data allow to interpret biofilm as a form of existence of human normal microflora. For the exchange of information within the biofilm between the individual cells of the same or different species bacteria use the signal molecules of the Quorum sensing system. Coordination of bacterial cells activity in the biofilms gives them significant advantages: in the biofilms bacteria are protected from the influence of the host protective factors and the antibacterial drugs.

  3. Degradation of monomethylhydrazine by two soil bacteria

    International Nuclear Information System (INIS)

    It has been reported that three heterotrophic soil bacteria had the capacity to degrade hydrazine. One of these organisms, Achromobacter sp., degraded hydrazine to N2 gas. Furthermore, it was reported that monomethylhydrazine (MMH) in Arredondo fine sand was mineralized to CO2, and that such degradation is microbial. However, microorganisms that degrade MMH have not been reported. MMH and hydrazine are chemically similar to one another. Therefore, this study was initiated to test the capacity of the two hydrazine-degrading bacteria, Achromobacter sp. and Pseudomonas sp., to degrade MMH

  4. CHARACTERIZATION OF NATURAL MICROCOSMS OF ESTUARINE MAGNETOTACTIC BACTERIA / CARACTERIZACIÓN DE MICROCOSMOS NATURALES DE BACTERIAS MAGNETOTÁCTICAS ESTUARINAS

    Scientific Electronic Library Online (English)

    ALEJANDRO, SALAZAR; ALVARO, MORALES; MARCO, MÁRQUEZ.

    2011-08-01

    Full Text Available No se ha reportado ningún estudio completo sobre microcosmos naturales de bacterias magnetotácticas (MTB) en estuarios o ambientes tropicales. Además, casi todos los estudios sobre las bacterias magnetotácticas se han desarrollado en aguas dulces alejadas del ecuador. Este trabajo se desarrolla sobr [...] e el ecuador y reporta una caracterización mineralógica y fisicoquímica detallada de dos microcosmos bacterianos estuarinos. Los resultados muestran que la lixiviación de minerales en los sedimentos puede ser un factor importante en la solubilización de elementos requeridos por las bacterias magnetotácticas. Específicamente, que el clinocloro, flogopita, nontronita y haloisita pueden estar entre los minerales más importantes en la lixiviación de hierro a los microcosmos estuarinos. Se concluye que la concentración de nitrato en el agua no debe ser tan baja como se ha reportado para lograr un crecimiento bacteriano óptimo. Las bacterias magnetotácticas no necesitan grandes cantidades de hierro disuelto para su crecimiento ni para la síntesis de magnetosomas. Abstract in english To date, no complete study of magnetotactic bacteria's (MTB) natural microcosms in estuarine or tropical environments has been reported. Besides, almost all the studies around magnetotactic bacteria have been based on fresh waters away from the Equator. In this work, we focused the experimental regi [...] on at the Equator and present a comprehensive mineralogical and physicochemical characterization of two estuarine bacterial microcosms. The results show that mineral lixiviation in the sediments may be an important factor in the solubilization of elements required by magnetotactic bacteria. Specifically, we show that clinochlore, phlogopite, nontronite, and halloysite could be among the main minerals that lixiviate iron to the estuarine microcosms. We conclude that nitrate concentration in the water should not be as low as those that have been reported for other authors to achieve optimal bacteria growth. It is confirmed that magnetotactic bacteria do not need large amounts of dissolved iron to grow or to synthesize magnetosomes.

  5. 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.

  6. The proteolytic system of lactic acid bacteria.

    Science.gov (United States)

    Mayo, B

    1993-12-01

    Lactic acid bacteria are widely used throughout the world, empirically or deliberately, in the manufacturing of several food and feed stuffs, including milk products (such as cheese, butter, yoghurt, buttermilk, etc.), fermented vegetables (pickles, olives and sauerkraut), sausages, sourdough bread and silage, due to their ability to convert sugars into lactic acid. Of these, dairy products are of outstanding economic importance. Starter cultures used in the dairy industry are mixtures of carefully selected lactic acid bacteria which are added to the milk to fulfil the desired fermentation. Dairy starter cultures must reach high densities in milk in order to produce lactic acid at the required rates for manufacturing. Under these conditions, amino acids supply becomes limitant due to their scarce concentration in milk and to the auxotrophies shown by many starter bacteria. This implies the necessity of a proteolytic system, able to degrade the most abundant protein in milk, casein, into assimilable amino acids and peptides. Casein degradation and utilization require the concerted action of proteinases, peptidases and amino acid and peptide uptake systems. This whole set of enzymes constitutes the proteolytic system. In this article an overview of the recent biochemical and genetic data on the proteolytic system of lactic acid bacteria will be presented. PMID:8172695

  7. NSAID enteropathy and bacteria: a complicated relationship.

    Science.gov (United States)

    Syer, Stephanie D; Blackler, Rory W; Martin, Rebeca; de Palma, Giada; Rossi, Laura; Verdu, Elena; Bercik, Premek; Surette, Michael G; Aucouturier, Anne; Langella, Philippe; Wallace, John L

    2015-04-01

    The clinical significance of small intestinal damage caused by nonsteroidal anti-inflammatory drugs (NSAIDs) remains under-appreciated. It occurs with greater frequency than the damage caused by these drugs in the upper gastrointestinal tract, but is much more difficult to diagnose and treat. Although the pathogenesis of NSAID enteropathy remains incompletely understood, it is clear that bacteria, bile, and the enterohepatic circulation of NSAIDs are all important factors. However, they are also interrelated with one another. Bacterial enzymes can affect the cytotoxicity of bile and are essential for enterohepatic circulation of NSAIDs. Gram-negative bacteria appear to be particularly important in the pathogenesis of NSAID enteropathy, possibly through release of endotoxin. Inhibitors of gastric acid secretion significantly aggravate NSAID enteropathy, and this effect is due to significant changes in the intestinal microbiome. Treatment with antibiotics can, in some circumstances, reduce the severity of NSAID enteropathy, but published results are inconsistent. Specific antibiotic-induced changes in the microbiota have not been causally linked to prevention of intestinal damage. Treatment with probiotics, particularly Bifidobacterium, Lactobacillus, and Faecalibacteriaum prausnitzii, has shown promising effects in animal models. Our studies suggest that these beneficial effects are due to colonization by the bacteria, rather than to products released by the bacteria. PMID:25572030

  8. Molecular evolution in bacteria: cell division

    OpenAIRE

    Trevors J.T.

    1998-01-01

    Molecular evolution in bacteria is examined with an emphasis on the self-assembly of cells capable of primitive division and growth during early molecular evolution. Also, the possibility that some type of encapsulation structure preceeded biochemical pathways and the assembly of genetic material is examined. These aspects will be considered from an evolutionary perspective.

  9. Probiotic Bacteria May Become Dormant during Storage

    OpenAIRE

    Lahtinen, Sampo J.; Gueimonde, Miguel; Ouwehand, Arthur C.; Reinikainen, Johanna P.; Salminen, Seppo J.

    2005-01-01

    The determination of bacterial viability in probiotic products is of economic, technological, and clinical significance. We compared four methods to enumerate three Bifidobacterium strains in fermented oat products during storage. A subpopulation of nonculturable cells retained a functional cell membrane typical of viable cells, indicating that probiotic bacteria become dormant during storage.

  10. Comparative activity of ciprofloxacin against anaerobic bacteria.

    OpenAIRE

    Sutter, V. L.; Kwok, Y. Y.; Bulkacz, J.

    1985-01-01

    The in vitro activity of ciprofloxacin was assessed against 362 strains of anaerobic bacteria and compared with that of cefoxitin, clindamycin, metronidazole, and mezlocillin. Only 31% of the strains tested were susceptible to ciprofloxacin. The other agents were active against most of the strains tested.

  11. Bioluminescent bacteria: lux genes as environmental biosensors

    OpenAIRE

    Nunes-Halldorson Vânia da Silva; Duran Norma Letícia

    2003-01-01

    Bioluminescent bacteria are widespread in natural environments. Over the years, many researchers have been studying the physiology, biochemistry and genetic control of bacterial bioluminescence. These discoveries have revolutionized the area of Environmental Microbiology through the use of luminescent genes as biosensors for environmental studies. This paper will review the chronology of scientific discoveries on bacterial bioluminescence and the current applications of bioluminescence in env...

  12. ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS

    Science.gov (United States)

    Seagrasses are adapted to being rooted in reduced, anoxic sediments with high rates of sulfate reduction. During the day, an oxygen gradient is generated around the roots, becoming anoxic at night. Thus, obligate anaerobic bacteria in the rhizosphere have to tolerate elevated oxy...

  13. Emerging Plant Pathogenic Bacteria and Global Warming

    Science.gov (United States)

    Several bacteria, previously classified as non-fluorescent, oxidase positive pseudomonads, Ralstonia, Acidovorax, and Burkholdria have emerged as serious problems world-wide. Perhaps the most destructive is R. solanacearum (RS), a soilborne pathogen with a very wide host range. RS race 3, biovar 2...

  14. A fantastic voyage for sliding bacteria.

    Science.gov (United States)

    Shrout, Joshua D

    2015-05-01

    A recent study showed that Salmonella enterica serovar Typhimurium exhibits sliding motility under magnesium-limited conditions. Overall, bacteria that exhibit this passive surface movement described as sliding share few common traits. This discovery provides an opportunity to revisit and better characterize appendage-independent bacterial motility. PMID:25777934

  15. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  16. Collective Sensing-Capacity of Bacteria Populations

    CERN Document Server

    Einolghozati, Arash; Fekri, Faramarz

    2012-01-01

    The design of biological networks using bacteria as the basic elements of the network is initially motivated by a phenomenon called quorum sensing. Through quorum sensing, each bacterium performs sensing the medium and communicating it to others via molecular communication. As a result, bacteria can orchestrate and act collectively and perform tasks impossible otherwise. In this paper, we consider a population of bacteria as a single node in a network. In our version of biological communication networks, such a node would communicate with one another via molecular signals. As a first step toward such networks, this paper focuses on the study of the transfer of information to the population (i.e., the node) by stimulating it with a concentration of special type of a molecules signal. These molecules trigger a chain of processes inside each bacteria that results in a final output in the form of light or fluorescence. Each stage in the process adds noise to the signal carried to the next stage. Our objective is ...

  17. Chitinolytic bacteria of the mammal digestive tract.

    Czech Academy of Sciences Publication Activity Database

    Šim?nek, Ji?í; Hodrová, Blanka; Barto?ová, H.; Kope?ný, Jan

    2001-01-01

    Ro?. 46, ?. 1 (2001), s. 76-78. ISSN 0015-5632 R&D Projects: GA ?R GA525/00/0984; GA AV ?R KSK5052113 Keywords : chitinolytic bacteria Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.776, year: 2001

  18. Phosphate solubilizing bacteria around Indian peninsula

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, M.J.B.D.; Nair, S.; Chandramohan, D.

    2000-01-01

    . Their ability to survive on carriers up to 60 days indicates that they could be effective seed organisms for field applications. These bacteria were found to be highly adaptive and therefore, can significantly contribute to the phosphate economy of the marine...

  19. Biochemistry and molecular biology of anammox bacteria.

    Science.gov (United States)

    Jetten, Mike S M; Niftrik, Laura van; Strous, Marc; Kartal, Boran; Keltjens, Jan T; Op den Camp, Huub J M

    2009-06-01

    Anaerobic ammonium-oxidizing (anammox) bacteria are one of the latest additions to the biogeochemical nitrogen cycle. These bacteria derive their energy for growth from the conversion of ammonium and nitrite into dinitrogen gas in the complete absence of oxygen. These slowly growing microorganisms belong to the order Brocadiales and are affiliated to the Planctomycetes. Anammox bacteria are characterized by a compartmentalized cell architecture featuring a central cell compartment, the "anammoxosome". Thus far unique "ladderane" lipid molecules have been identified as part of their membrane systems surrounding the different cellular compartments. Nitrogen formation seems to involve the intermediary formation of hydrazine, a very reactive and toxic compound. The genome of the anammox bacterium Kuenenia stuttgartiensis was assembled from a complex microbial community grown in a sequencing batch reactor (74% enriched in this bacterium) using a metagenomics approach. The assembled genome allowed the in silico reconstruction of the anammox metabolism and identification of genes most likely involved in the process. The present anammox pathway is the only one consistent with the available experimental data, thermodynamically and biochemically feasible, and consistent with Ockham's razor: it invokes minimum biochemical novelty and requires the fewest number of biochemical reactions. The worldwide presence of anammox bacteria has now been established in many oxygen-limited marine and freshwater systems, including oceans, seas, estuaries, marshes, rivers and large lakes. In the marine environment over 50% of the N(2) gas released may be produced by anammox bacteria. Application of the anammox process offers an attractive alternative to current wastewater treatment systems for the removal of ammonia-nitrogen. Currently, at least five full scale reactor systems are operational. PMID:19247843

  20. The interaction of bacteria and metal surfaces

    International Nuclear Information System (INIS)

    This review discusses different examples for the interaction of bacteria and metal surfaces based on work reported previously by various authors and work performed by the author with colleagues at other institutions and with his graduate students at CEEL. Traditionally it has been assumed that the interaction of bacteria with metal surfaces always causes increased corrosion rates ('microbiologically influenced corrosion' (MIC)). However, more recently it has been observed that many bacteria can reduce corrosion rates of different metals and alloys in many corrosive environments. For example, it has been found that certain strains of Shewanella can prevent pitting of Al 2024 in artificial seawater, tarnishing of brass and rusting of mild steel. It has been observed that corrosion started again when the biofilm was killed by adding antibiotics. The mechanism of corrosion protection seems to be different for different bacteria since it has been found that the corrosion potential Ecorr became more negative in the presence of Shewanella ana and algae, but more positive in the presence of Bacillus subtilis. These findings have been used in an initial study of the bacterial battery in which Shewanella oneidensis MR-1 was added to a cell containing Al 2024 and Cu in a growth medium. It was found that the power output of this cell continuously increased with time. In the microbial fuel cell (MFC) bacteria oxidize the fuel and transfer electrons directly to the anoded transfer electrons directly to the anode. In initial studies EIS has been used to characterize the anode, cathode and membrane properties for different operating conditions of a MFC that contained Shewanella oneidensis MR-1. Cell voltage (V)-current density (i) curves were obtained using potentiodynamic sweeps. The current output of a MFC has been monitored for different experimental conditions

  1. 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. ...

  2. 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 (...

  3. Physiological Achilles' heels of Enteropathogenic bacteria in livestock

    OpenAIRE

    Becker, P.M.

    2005-01-01

    An elaborate feeding regimen of animals, which takes advantage of the Achilles' heels of enteropathogenic bacteria, can possibly enable prophylaxis in the intestinal tract, attenuate actual disease symptoms, accelerate recovery from a bacterial gastroenteritis or ensure food safety. There is a wide spectrum of conceivable weak spots in bacteria. Some pathogenic bacteria cannot use certain compounds, or use them less efficient than beneficial bacteria. By addition of such substances to animal ...

  4. Effect of radiation on activity of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    The effect of ?-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 ?-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

  5. Population dynamics of bacteria introduced into bentonite amended soil.

    OpenAIRE

    Heijnen, C. E.

    1992-01-01

    Bacteria have frequently been introduced into the soil environment, e.g. for increasing crop production or for biological control purposes. Many applications require high numbers of surviving organisms in order to be effective. However, survival of bacteria after introduction into soil is generally poor, and numbers of introduced bacteria have been known to decrease from 10 9to approximately 10 3cells/g soil in 25 days. Thus, if bacteria are to be used as effective microbial inoculants to, a ...

  6. Probiotic bacteria in prevention and treatment of diarrhea

    OpenAIRE

    Jasmina Havranek; Šimun Zamberlin; Iva Dolen?i? Špehar; Tamara Prtilo; Milna Tudor; Dubravka Samaržija

    2009-01-01

    Probiotic bacteria have beneficial effects in prevention and treatment of different diseases. The results of preventive and therapeutic effect of probiotic bacteria on diarrhea during last ten years are shown in this paper. The greatest preventive and therapeutic effect of probiotic bacteria was identified for acute diarrhea in children caused by rotaviruses. Significant, but slightly lower effect of probiotic bacteria was proved for antibiotic associated diarrhea. Positive effect in preventi...

  7. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    OpenAIRE

    DWI SURYANTO; SITI PATONAH; ERMAN MUNIR

    2010-01-01

    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 sup...

  8. Structured habitats and the evolution of anticompetitor toxins in bacteria.

    Science.gov (United States)

    Chao, L; Levin, B R

    1981-10-01

    We demonstrate that in liquid cultures, defined in this study as a mass habitat, the outcome of competition between Escherichia coli that produce an antibacterial toxin (colicin) and sensitive E. coli is frequency dependent; the colicinogenic bacteria are at an advantage only when fairly common (frequencies in excess of 2 X 10(-2)). However, we also show that in a soft agar matrix, a structured habitat, the colicinogenic bacteria have an advantage even when initially rare (frequencies as low as 10(-6)). These contrasting outcomes are attributed to the colicinogenic bacteria's lower intrinsic growth rate relative to the sensitive bacteria and the different manner in which bacteria and resources are partitioned in the two types of habitats. Bacteria in a liquid culture exist as randomly distributed individuals and the killing of sensitive bacteria by the colicin augments the amount of resource available to the colicinogenic bacteria to an extent identical to that experienced by the surviving sensitive bacteria. On the other hand, the bacteria in a soft agar matrix exist as single-clone colonies. As the colicinogenic colonies release colicin, they kill neighboring sensitive bacteria and form an inhibition zone around themselves. By this action, they increase the concentration of resources around themselves and overcome their growth rate disadvantage. We suggest that structured habitats are more favorable for the evolution of colicinogenic bacteria. PMID:7031647

  9. Coaggregation of oral bacteria. A physicochemical study based on microcalorimetry

    OpenAIRE

    Postollec, Florence

    2005-01-01

    Coaggregation is defined as the specific recognition and interaction between bacteria in suspension. It was first reported in 1970 by Gibbons & Nygaard and has been mostly described between bacteria isolated from human dental plaque. Since the last ten years, coaggregation has been recognized amongst bacteria isolated from freshwater ecosystems, human and animal gastrointestinal and urogenital tracts. ... Zie: Summary.

  10. Resistant bacteria in stem cell transplant recipients

    Directory of Open Access Journals (Sweden)

    Nucci Marcio

    2002-01-01

    Full Text Available Bacterial infections account for most infections in hematopoietic stem cell transplant recipients. While early mortality reduced dramatically with the introduction of the concept of empirical antibiotic therapy in neutropenic patients, no effect of prophylaxis on the mortality was observed in many studies. On the other hand, antibiotic prophylaxis has resulted in the emergence of resistance among bacteria. In addition, the choice of the antibiotic regimen for empirical therapy and the practices of antibiotic therapy during neutropenia may result in a significant shift in the pattern of bacterial infections. The use of quinolones and vancomycin as prophylaxis, and of carbapenems and vancomycin in the empirical antibiotic therapy, are associated with the appearance of resistant Gram-positive and Gram-negative bacteria. Therefore, hematologists must be aware of the impact of these practices on the emergence of infections due to multi-resistant pathogens, since these infections may be associated with increased mortality.

  11. Biotechnological potential of Clostridium butyricum bacteria

    Scientific Electronic Library Online (English)

    Daria, Szymanowska-Powa& #322; owska; Dorota, Orczyk; Katarzyna, Leja.

    2014-09-01

    Full Text Available In response to demand from industry for microorganisms with auspicious biotechnological potential, a worldwide interest has developed in bacteria and fungi isolation. Microorganisms of interesting metabolic properties include non-pathogenic bacteria of the genus Clostridium, particularly C. acetobut [...] ylicum, C. butyricum and C. pasteurianum. A well-known property of C. butyricum is their ability to produce butyric acid, as well as effectively convert glycerol to 1,3-propanediol (38.2 g/L). A conversion rate of 0.66 mol 1,3-propanediol/mol of glycerol has been obtained. Results of the studies described in the present paper broaden our knowledge of characteristic features of C. butyricum specific isolates in terms of their phylogenetic affiliation, fermentation capacity and antibacterial properties.

  12. Sulfate inhibition effect on sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    Muftah H El-Naas

    2008-12-01

    Full Text Available There is an increasing interest in the potential of bacterial sulfate reduction as an alternative method for sulfate removal from wastewater. Under anaerobic conditions, sulfate-reducing bacteria (SRB utilize sulfate to oxidize organic compounds and generate sulfide (S2-. SRB were successfully isolated from sludge samples obtained from a local petroleum refinery, and used for sulfate removal. The effects of initial sulfate concentration, temperature and pH on the rate of bacterial growth and anaerobic sulfate removal were investigated and the optimum conditions were identified. The experimental data were used to determine the parameters of two proposed kinetic model, which take into consideration substrate inhibition effect. Keywords: Sulfate Reducing Bacteria, Sulfate, Kinetic Model, Biotreatement, Inhibition Received: 31 August 2008 / Received in revised form: 18 September 2008, Accepted: 18 September 2008 Published online: 28 September 2008

  13. Effect of Essential Oils on Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Filomena Nazzaro

    2013-11-01

    Full Text Available The increasing resistance of microorganisms to conventional chemicals and drugs is a serious and evident worldwide problem that has prompted research into the identification of new biocides with broad activity. Plants and their derivatives, such as essential oils, are often used in folk medicine. In nature, essential oils play an important role in the protection of plants. Essential oils contain a wide variety of secondary metabolites that are capable of inhibiting or slowing the growth of bacteria, yeasts and moulds. Essential oils and their components have activity against a variety of targets, particularly the membrane and cytoplasm, and in some cases, they completely change the morphology of the cells. This brief review describes the activity of essential oils against pathogenic bacteria.

  14. Targeted delivery of colloids by swimming bacteria

    Science.gov (United States)

    Koumakis, N.; Lepore, A.; Maggi, C.; di Leonardo, R.

    2013-10-01

    The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems.

  15. [RAPD analysis of plant pathogenic coryneform bacteria].

    Science.gov (United States)

    Yin, Yan-Ni; Chen, Yong-Fang; Li, Shi-Mo; Guo, Jian-Hua

    2005-12-01

    RAPD analysis was used for the taxonomy of plant pathogenic coryneform bacteria, especially for the classification of two new pathogens (Curtobacterium flaccumfaciens pv. basellae pv. nov. and Curtobacterium flaccumfaciens pv. beticola pv. nov.). 20 random primers were screened from 50 ones to detect polymorphism among the total strains used. 80.4% were polymorphic bands among the 225 ones produced. The results of pairwise similarity and UPGMA cluster analysis suggest that the two new pathovars of sugar beet (Beta vulgaris var. saccharifera) and malabar spinach (Basella rubra) are genetically close related with Curtobacterium flacumfaciens, and the minimal similarity coefficient is 0.6511. According to the RAPD analysis and previous research, some newly made taxonomic changes of the plant pathogenic coryneform bacteria are discussed. PMID:16496687

  16. Probiotic Lactic Acid Bacteria: A Review

    Directory of Open Access Journals (Sweden)

    Emiliano J. Quinto

    2014-09-01

    Full Text Available Lactic acid bacteria (LAB play a critical role in food production and health maintenance. There is an increasing interest in these species to reveal the many possible health benefits associated with them. The actions of LAB are species and strain specific, and depend on the amount of bacteria available in the gastrointestinal tract. Consumers are very concerned of chemical preservatives and processed foods. However, products with or processed with LAB are accepted as a natural way to preserve food and promote health. This paper aimed to review the recent data in regard to the role of probiotic LAB in the preservation of foods, in the immunomodulation in the gastrointestinal tract, and in its health benefits

  17. On Ants, Bacteria and Dynamic Environments

    CERN Document Server

    Ramos, V; Rosa, A C; Ramos, Vitorino; Fernandes, Carlos; Rosa, Agostinho C.

    2005-01-01

    Wasps, bees, ants and termites all make effective use of their environment and resources by displaying collective swarm intelligence. Termite colonies - for instance - build nests with a complexity far beyond the comprehension of the individual termite, while ant colonies dynamically allocate labor to various vital tasks such as foraging or defense without any central decision-making ability. Recent research suggests that microbial life can be even richer: highly social, intricately networked, and teeming with interactions, as found in bacteria. What strikes from these observations is that both ant colonies and bacteria have similar natural mechanisms based on Stigmergy and Self-Organization in order to emerge coherent and sophisticated patterns of global behaviour. Keeping in mind the above characteristics we will present a simple model to tackle the collective adaptation of a social swarm based on real ant colony behaviors (SSA algorithm) for tracking extrema in dynamic environments and highly multimodal co...

  18. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C

    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-genome gene family and single gene sequence comparisons yielded similar phylogenetic trees of the sequenced chromosomes indicating a concerted vertical evolution of large gene sets. Chromosomal synteny of genes is not preserved in the phylum Chlorobi. The accessory genome is characterized by anomalous oligonucleotide usage and endows the strains with individual features for transport, secretion, cell wall, extracellular constituents, and a few elements of the biosynthetic apparatus. Giant genes are a peculiar feature of the genera Chlorobium and Prosthecochloris. The predicted proteins have a huge molecular weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment.

  19. Seeing Streptococcus pneumoniae, a Common Killer Bacteria

    DEFF Research Database (Denmark)

    Kjærgaard, Rikke Schmidt; Andersen, Ebbe Sloth

    2014-01-01

    Look around you. The diversity and complexity of life on earth is overwhelming and data continues to grow. In our desire to understand and explain everything scientifically from molecular evolution to supernovas we depend on visual representations. This paper investigates visual representations of the bacteria Streptococcus pneumoniae by use of ink, watercolours and computer graphics. We propose a novel artistic visual rendering of Streptococcus pneumoniae and ask what the value of these kind of representations are compared to traditional scientific data. We ask if drawings and computer-assisted representations can add to our scientific knowledge about this dangerous bacteria. Is there still a role for the scientific illustrator in the scientific process and synthesis of scientific knowledge?

  20. Bacteria slingshot more on soft surfaces

    Science.gov (United States)

    Zhang, Rongrong; Ni, Lei; Jin, Zhenyu; Li, Jiahong; Jin, Fan

    2014-11-01

    Adaptive responses greatly improve the competitive capacities of bacteria in diverse environments. Here, we investigate whether bacteria can adapt to a microenvironment with distinctive softness by examining the type-IV pili (TFP)-mediated motility of Pseudomonas aeruginosa cells on brush-like surfaces that are grafted with a layer of thermally sensitive polymer chains, where the softness of the brush-layer is tunable by applying a small temperature change (from 30 to 37?°C). We report that P. aeruginosa cells slingshot more on soft surfaces at a shear-thinning condition, which greatly facilitates their surface crawling by means of reducing energy dissipation. This adaptive response suggests that P. aeruginosa cells may be able to sense the local viscoelasticity and then deploy TFP to adapt to their physical surroundings.

  1. Anger management: bacteria soothe the savage host.

    Science.gov (United States)

    Seed, Patrick C

    2013-06-01

    A 5-year-old girl has come to you a week after completing a course of antibiotics for a febrile urinary tract infection (UTI). She now seems well and energetic. A urinalysis is now clear without traces of inflammation, including an absence of protein, blood, leukocyte esterase, and nitrites. Her urine is submitted for a test of cure and comes back positive, with over 100,000 colonies per milliliter of E. coli, the same kind of bacteria that was cultured from her urine when she was symptomatic with the UTI. Perplexed, her mother asks how her child can have bacteria once again in her bladder but not be symptomatic and asks if antibiotics are again necessary. PMID:23728167

  2. Sulfate inhibition effect on sulfate reducing bacteria

    OpenAIRE

    Muftah H. El-Naas; Huda Al Hassani; Sulaiman Al Zuhair

    2008-01-01

    There is an increasing interest in the potential of bacterial sulfate reduction as an alternative method for sulfate removal from wastewater. Under anaerobic conditions, sulfate-reducing bacteria (SRB) utilize sulfate to oxidize organic compounds and generate sulfide (S2-). SRB were successfully isolated from sludge samples obtained from a local petroleum refinery, and used for sulfate removal. The effects of initial sulfate concentration, temperature and pH on the rate of bacterial growth an...

  3. Metabolic flexibility of sulfate-reducing bacteria

    OpenAIRE

    Plugge, C.M.; Zhang, Weinwen; Scholten, J.C.M.; Stams, A J M

    2011-01-01

    Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas me...

  4. Aztreonam selective agar for gram positive bacteria.

    OpenAIRE

    Wood, W.; Harvey, G.; Olson, E. S.; Reid, T. M.

    1993-01-01

    Aztreonam blood agar, a new selective medium for Gram positive aerobic bacteria, was evaluated in comparison with conventional media for skin swabs. Aztreonam agar increased the number of isolates of Staphylococcus aureus by 17%. By producing purer growths on primary isolation, it significantly speeded up the identification and sensitivity testing of staphylococci and streptococci. All major Gram positive aerobic pathogens grow on this medium. Aztreonam agar is now an established addition to ...

  5. High efficiency recombineering in lactic acid bacteria

    OpenAIRE

    van Pijkeren, Jan-Peter; BRITTON, ROBERT A.

    2012-01-01

    The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to Gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lact...

  6. Tumour targeting with systemically administered bacteria.

    LENUS (Irish Health Repository)

    Morrissey, David

    2012-01-31

    Challenges for oncology practitioners and researchers include specific treatment and detection of tumours. The ideal anti-cancer therapy would selectively eradicate tumour cells, whilst minimising side effects to normal tissue. Bacteria have emerged as biological gene vectors with natural tumour specificity, capable of homing to tumours and replicating locally to high levels when systemically administered. This property enables targeting of both the primary tumour and secondary metastases. In the case of invasive pathogenic species, this targeting strategy can be used to deliver genes intracellularly for tumour cell expression, while non-invasive species transformed with plasmids suitable for bacterial expression of heterologous genes can secrete therapeutic proteins locally within the tumour environment (cell therapy approach). Many bacterial genera have been demonstrated to localise to and replicate to high levels within tumour tissue when intravenously (IV) administered in rodent models and reporter gene tagging of bacteria has permitted real-time visualisation of this phenomenon. Live imaging of tumour colonising bacteria also presents diagnostic potential for this approach. The nature of tumour selective bacterial colonisation appears to be tumour origin- and bacterial species- independent. While originally a correlation was drawn between anaerobic bacterial colonisation and the hypoxic nature of solid tumours, it is recently becoming apparent that other elements of the unique microenvironment within solid tumours, including aberrant neovasculature and local immune suppression, may be responsible. Here, we consider the pre-clinical data supporting the use of bacteria as a tumour-targeting tool, recent advances in the area, and future work required to develop it into a beneficial clinical tool.

  7. Are public library books contaminated by bacteria?

    Science.gov (United States)

    Brook, S J; Brook, I

    1994-10-01

    The microbial flora on the surfaces of 15 books obtained from a public library and from 15 books obtained from a family household were studied. Staphylococcus epidermidis was recovered from 4 of the library books and 3 of the family household books. The number of organisms per page was between one to four. This data illustrates the safety of using library books, as they do not serve as a potential source of transmission of virulent bacteria. PMID:7722550

  8. Probiotics Bacteria in Fermented Dairy Products

    OpenAIRE

    Omer Turki Mamdoh Ershidat; Ayman Suliman Mazahreh

    2009-01-01

    The nutritional value of diary based product that contains probiotic bacteria on the gastrointestinal health and functions have been investigated in this study. Both probiotic Lactobacillus bulgaricus and Streptococcus thermophilus species, contribute to the formation of yogurt as a result of anaerobic fermentation of lactic acid in the milk. The benefits of yogurt consumption on the gastrointestinal function mediated through the gut micro flora, bowel transit and the enhancement of gastroint...

  9. Application of Pulsed Electric Field on Bacteria.

    Czech Academy of Sciences Publication Activity Database

    Kadlec, Tomáš; Babický, Václav; ?lupek, Martin; Vrbová, M.

    Prague : Czech Technical University in Prague, 2011 - (Pospíšilová, M.; Vrbová, M.; Machá?, R.), s. 161-164 ISBN 978-80-01-04915-0. [Instruments and Methods for Biology and Medicine 2011. Kladno (CZ), 02.06.2011-02.06.2011] R&D Projects: GA AV ?R IAAX00430802; GA ?R(CZ) GD104/09/H080 Institutional research plan: CEZ:AV0Z20430508 Keywords : Pulsed Electric Field * Bacteria Subject RIV: BO - Biophysics

  10. Adenoid Reservoir for Pathogenic Biofilm Bacteria?

    OpenAIRE

    Nistico, L.; Kreft, R.; Gieseke, A.; Coticchia, J. M.; Burrows, A.; Khampang, P.; Liu, Y; Kerschner, J. E.; Post, J C; Lonergan, S.; Sampath, R.; Hu, F.Z.; Ehrlich, G. D.; Stoodley, P; Hall-Stoodley, L.

    2011-01-01

    Biofilms of pathogenic bacteria are present on the middle ear mucosa of children with chronic otitis media (COM) and may contribute to the persistence of pathogens and the recalcitrance of COM to antibiotic treatment. Controlled studies indicate that adenoidectomy is effective in the treatment of COM, suggesting that the adenoids may act as a reservoir for COM pathogens. To investigate the bacterial community in the adenoid, samples were obtained from 35 children undergoing adenoidectomy for ...

  11. Ferric Iron Reduction by Acidophilic Heterotrophic Bacteria

    OpenAIRE

    Johnson, D. Barrie; McGinness, Stephen

    1991-01-01

    Fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. Both rates and extents of ferric iron reduction were highly strain dependent. No acidophilic heterotroph reduced nitrate or sulfate, and (limited) reduction of manganese(IV) was note...

  12. Flow cytometry, fluorescent probes, and flashing bacteria

    OpenAIRE

    Bunthof, C. J.

    2002-01-01

     Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk, probiotic In food industry there is a perceived need for rapid methods for detection and viability assessment of microbes. Fluorescent staining and flow cytometry provide excellent tools for microbial analysis. This thesis describes fluorescent techniques for assessment of the physiological state of lactic acid ba...

  13. Dynamics of swimming bacteria at complex interfaces

    OpenAIRE

    Lopez, Diego; Lauga, Eric

    2014-01-01

    Flagellated bacteria exploiting helical propulsion are known to swim along circular trajectories near surfaces. Fluid dynamics predicts this circular motion to be clockwise (CW) above a rigid surface (when viewed from inside the fluid) and counter-clockwise (CCW) below a free surface. Recent experimental investigations showed that complex physicochemical processes at the nearby surface could lead to a change in the direction of rotation, both at solid surfaces absorbing slip...

  14. Natural Selection of Antibiotic Resistant Bacteria

    Science.gov (United States)

    Dave Cavanagh

    2012-06-26

    In this activity (p.3-4 of PDF), learners learn about disease transmission and antibiotic resistance. In this activity, an educator shows what could happen if one learner has not washed his/her hands properly before lunch and becomes ill as a result. The educator uses beans to illustrate both disease transmission and the development of antibiotic resistant bacteria. Use this activity to discuss the importance of proper hygiene, disease transmission, and both natural and artificial selection.

  15. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 103 to 105 mL-1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the bioflized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  16. Pattern Formation in Growing Polar Bacteria

    Science.gov (United States)

    Yang, Xingbo; Marchetti, M.; Marenduzzo, Davide

    2013-03-01

    We analyze a continuum model of a bacterial suspension that includes motility suppression from steric repulsion, polar alignment, and bacteria reproduction and death. Using a combination of linear stability analysis and numerical solution of the nonlinear equations, we demonstrate that the model exhibits a rich variety of emergent structures, corresponding to generic patterns seen in experiments. Motility suppression in a crowded environment gives rise to a density phase separation, regulated by the growth/death of the bacteria, as demonstrated earlier by Cates et al. [PNAS 107, 11715-11720(2010)], with spherically symmetric patterns similar to those observed in S. typhimurium. The addition of polar alignment yields new ring/band and swirl/spiral structures resembling those observed in E.coli colonies. The stationary/traveling nature of the patterns and their symmetry is classified and summarized in a phase diagram. We analyze a continuum model of a bacterial suspension that includes motility suppression from steric repulsion, polar alignment, and bacteria reproduction and death. Using a combination of linear stability analysis and numerical solution of the nonlinear equations, we demonstrate that the model exhibits a rich variety of emergent structures, corresponding to generic patterns seen in experiments. Motility suppression in a crowded environment gives rise to a density phase separation, regulated by the growth/death of the bacteria, as demonstrated earlier by Cates et al. [PNAS 107, 11715-11720(2010)], with spherically symmetric patterns similar to those observed in S. typhimurium. The addition of polar alignment yields new ring/band and swirl/spiral structures resembling those observed in E.coli colonies. The stationary/traveling nature of the patterns and their symmetry is classified and summarized in a phase diagram. This work was supported by the NSF through grant DMR-1004789.

  17. Tolerance of Anaerobic Bacteria to Chlorinated Solvents

    OpenAIRE

    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 concentrati...

  18. Electromagnetic low-frequency fields and bacteria.

    Czech Academy of Sciences Publication Activity Database

    Foltýn, D.; ?ermáková, E.; Kolá?ová, M.; Bartušek, Karel

    Košice : RVS VLA Košice, 2002 - (Džunda, M.; Br?nová, B.), s. 133 - 137 ISBN 80-7166-034-5. [New trends of development in aviation. Košice (SK), 01.09.2002] Institutional research plan: CEZ:AV0Z2065902 Keywords : low-frequency fields * bacteria Staphylococcus aureus * low-frequency ELM fields Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. Phenotypic switching : an opportunity to bacteria thrive

    OpenAIRE

    Sousa, Ana Margarida; Machado, Idalina; Pereira, Maria Ol??via

    2012-01-01

    Bacteria in nature are ???plagued??? by various unpredictable environmental stresses, being population diversity one of the strategies adopted to survive. Phenotypic switching is one of the evolution processes that causes commutation between phenotypic states. This phenomenon shows up as variation in colony morphology. Alterations in colony morphotype traits may reveal altered cellular basis phenotype which can confer ensured virulence, antimicrobial resistance and persistence. However, the s...

  20. Carotenoid biosynthesis in extremophilic Deinococcus-Thermus bacteria.

    Science.gov (United States)

    Tian, Bing; Hua, Yuejin

    2010-11-01

    Bacteria from the phylum Deinococcus-Thermus are known for their resistance to extreme stresses including radiation, oxidation, desiccation and high temperature. Cultured Deinococcus-Thermus bacteria are usually red or yellow pigmented because of their ability to synthesize carotenoids. Unique carotenoids found in these bacteria include deinoxanthin from Deinococcus radiodurans and thermozeaxanthins from Thermus thermophilus. Investigations of carotenogenesis will help to understand cellular stress resistance of Deinococcus-Thermus bacteria. Here, we discuss the recent progress toward identifying carotenoids, carotenoid biosynthetic enzymes and pathways in some species of Deinococcus-Thermus extremophiles. In addition, we also discuss the roles of carotenoids in these extreme bacteria. PMID:20832321

  1. 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.

  2. The role of bacteria in oral cancer

    Directory of Open Access Journals (Sweden)

    Chocolatewala Noureen

    2010-12-01

    Full Text Available Despite the widening interest in the possible association between bacteria and different stages of cancer development, our knowledge in its relation to oral cancers remains inadequate. The aim of this review article is to derive a better understanding on the role of various micro-organisms in the etiogenesis of oral cancers through all the available data on the pubmed. Different bacteria have been proposed to induce carcinogenesis either through induction of chronic inflammation or by interference, either directly or indirectly, with eukaryotic cell cycle and signaling pathways, or by metabolism of potentially carcinogenic substances like acetaldehyde causing mutagenesis. Studies have shown diversity of isolated bacterial taxa between the oral cancer tissue specimens and the control, with Exiguobacterium oxidotolerans, Prevotella melaninogenica, Staphylococcus aureus and Veillonella parvula being specific for tumorogenic tissues. Most isolates are saccharolytic and acid tolerant. Streptococcus anginosus, commonly linked with esophageal and pharyngeal cancers, is not of significance in oral cancers. Similarly, significant salivary specificity is noted for three bacteria, namely, Capnocytophaga gingivalis, P. melaninogenica, and Streptococcus mitis in oral cancer patients, making these species salivary markers for the early detection of oral cancers and thus improving the survival rate significantly. Also, such high degree of bacterial specificity in oral cancers has also provoked the designing of new treatment options for cancer prevention by way of vaccine delivery. However, for the success of these steps, a deeper exploration into this subject with a greater understanding is warranted.

  3. Fecal indicator bacteria at Havana Bay

    International Nuclear Information System (INIS)

    Aims: Fecal indicator bacteria concentrations were evaluated in Havana Bay. Methods: Concentrations of traditional fecal indicator bacteria were calculated between April 2010 and February 2011, by MPN methods. Concentrations of thermo tolerant coliform (CTT), Escherichia coli, fecal streptococci (EF), intestinal enterococci (ENT) in seawater, and Clostridium perfringens in sediment surface, were determined. Results: CTT and E. coli levels were far above Cuban water quality standard for indirect contact with water, showing the negative influence of sewage and rivers on the bay. The EF and ENT were measured during sewage spills at the discharge site and they were suitable indicators of fecal contamination, but these indicators didn't show the same behavior in other selected sites. This result comes from its well-known inactivation by solar light in tropical zones and the presumable presence of humid acids in the waters of the bay. Conclusion: Fecal indicator bacteria and its statistical relationships reflect recent and chronic fecal contamination at the bay and near shores.

  4. High efficiency recombineering in lactic acid bacteria.

    Science.gov (United States)

    van Pijkeren, Jan-Peter; Britton, Robert A

    2012-05-01

    The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lactic acid bacteria. Mutations were incorporated in the chromosome of Lactobacillus reuteri and Lactococcus lactis without selection at frequencies ranging between 0.4% and 19%. Whole genome sequence analysis showed that ssDNA recombineering is specific and not hypermutagenic. To highlight the utility of ssDNA recombineering we reduced the intrinsic vancomymycin resistance of L. reuteri >100-fold. By creating a single amino acid change in the D-Ala-D-Ala ligase enzyme we reduced the minimum inhibitory concentration for vancomycin from >256 to 1.5?µg/ml, well below the clinically relevant minimum inhibitory concentration. Recombineering thus allows high efficiency mutagenesis in lactobacilli and lactococci, and may be used to further enhance beneficial properties and safety of strains used in medicine and industry. We expect that this work will serve as a blueprint for the adaptation of ssDNA recombineering to other gram-positive bacteria. PMID:22328729

  5. Distribution of coliform bacteria in waste water

    Directory of Open Access Journals (Sweden)

    Chandan Kumar Bahura

    2012-01-01

    Full Text Available Biological activity of water can be apparently judged by the colonization of bacteria (microbes. In order to find out the extent of pollution and the relationship between inorganic matters and microbiota, a quantitative and qualitative analysis of bacteria in various types of sewage waters, namely sewage water by the residential colonies (group I, industrial waste water (group II, sewage treatment hub (group III, unorganized collected waste water (group IV and old residential waste collection center (group V, of Bikaner city (Rajasthan, India was carried out from February, 2010 to May, 2010. Water samples were taken from surface only owing to low depth and investigated for various abiotic factors (viz. transparency, pH, carbonate, bicarbonate, total alkalinity, total hardness, salinity, chloride, calcium, magnesium, sulphate, nitrate, silica, and inorganic phosphorous and biotic factors (viz. number and diversity of bacteria. The domestic sewage water causes major water borne diseases basing upon Total Bacterial Count (TBC and coliform Count (CC. The coliform count in the present study ranged from 2.5 to 5.12 MPN/mL. Comparision of microbial population in sewage water from all different Groups was done and the higher values of TBC and CC were recorded only in Sewage treatement hub (Group III.

  6. Bacteria-powered battery on paper.

    Science.gov (United States)

    Fraiwan, Arwa; Choi, Seokheun

    2014-12-21

    Paper-based devices have recently emerged as simple and low-cost paradigms for fluid manipulation and analytical/clinical testing. However, there are significant challenges in developing paper-based devices at the system level, which contain integrated paper-based power sources. Here, we report a microfabricated paper-based bacteria-powered battery that is capable of generating power from microbial metabolism. The battery on paper showed a very short start-up time relative to conventional microbial fuel cells (MFCs); paper substrates eliminated the time traditional MFCs required to accumulate and acclimate bacteria on the anode. Only four batteries connected in series provided desired values of current and potential to power an LED for more than 30 minutes. The battery featured (i) a low-cost paper-based proton exchange membrane directly patterned on commercially available parchment paper and (ii) paper reservoirs for holding the anolyte and the catholyte for an extended period of time. Based on this concept, we also demonstrate the use of paper-based test platforms for the rapid characterization of electricity-generating bacteria. This paper-based microbial screening tool does not require external pumps/tubings and represents the most rapid test platform (<50 min) compared with the time needed by using traditional screening tools (up to 103 days) and even recently proposed MEMS arrays (< 2 days). PMID:25363848

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

    International Nuclear Information System (INIS)

    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. Varllenging 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 (1,2), and we anticipate one more publication (3). The publications describe development of methods and results of studies of structural dynamics of metal-resistant bacteria that contribute to more comprehensive understanding of the architecture, function, and environmental dynamics of bacterial and cellular systems. The results of this LDRD were presented in invited talks and contributed presentations at five national and international conferences and five seminar presentations at the external institutions. These included invited talks at the conferences of Gordon Research, Materials Research and American Chemical Societies. Our scientific results and methodologies developed in this project enabled us to receive new funding for the multiyear project 'Chromium transformation pathways in metal-reducing bacteria' funded by the University of California Lab Fees Program ($500,000, 5/1/09 - 4/30/2012), with our proposal being ranked 1st from a total of 138 in the Earth, Energy, Environmental and Space Sciences panel.

  8. Phylogenetic distribution of translational GTPases in bacteria

    Directory of Open Access Journals (Sweden)

    Remm Maido

    2007-01-01

    Full Text Available Abstract Background Translational GTPases are a family of proteins in which GTPase activity is stimulated by the large ribosomal subunit. Conserved sequence features allow members of this family to be identified. Results To achieve accurate protein identification and grouping we have developed a method combining searches with Hidden Markov Model profiles and tree based grouping. We found all the genes for translational GTPases in 191 fully sequenced bacterial genomes. The protein sequences were grouped into nine subfamilies. Analysis of the results shows that three translational GTPases, the translation factors EF-Tu, EF-G and IF2, are present in all organisms examined. In addition, several copies of the genes encoding EF-Tu and EF-G are present in some genomes. In the case of multiple genes for EF-Tu, the gene copies are nearly identical; in the case of multiple EF-G genes, the gene copies have been considerably diverged. The fourth translational GTPase, LepA, the function of which is currently unknown, is also nearly universally conserved in bacteria, being absent from only one organism out of the 191 analyzed. The translation regulator, TypA, is also present in most of the organisms examined, being absent only from bacteria with small genomes. Surprisingly, some of the well studied translational GTPases are present only in a very small number of bacteria. The translation termination factor RF3 is absent from many groups of bacteria with both small and large genomes. The specialized translation factor for selenocysteine incorporation – SelB – was found in only 39 organisms. Similarly, the tetracycline resistance proteins (Tet are present only in a small number of species. Proteins of the CysN/NodQ subfamily have acquired functions in sulfur metabolism and production of signaling molecules. The genes coding for CysN/NodQ proteins were found in 74 genomes. This protein subfamily is not confined to Proteobacteria, as suggested previously but present also in many other groups of bacteria. Conclusion Four of the translational GTPase subfamilies (IF2, EF-Tu, EF-G and LepA are represented by at least one member in each bacterium studied, with one exception in LepA. This defines the set of translational GTPases essential for basic cell functions.

  9. 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 in sensory rankings. It was concluded that lactic acid bacteria may not be necessary for successful cocoa fermentation. PMID:25889523

  10. Clay-Bacteria Systems and Biofilm Production

    Science.gov (United States)

    Steiner, J.; Alimova, A.; Katz, A.; Steiner, N.; Rudolph, E.; Gottlieb, P.

    2007-12-01

    Soil clots and the aerosol transport of bacteria and spores are promoted by the formation of biofilms (bacteria cells in an extracellular polymeric matrix). Biofilms protect microorganisms by promoting adhesion to both organic and inorganic surfaces. Time series experiments on bacteria-clay suspensions demonstrate that biofilm growth is catalyzed by the presence of hectorite in minimal growth media for the studied species: Gram negatives (Pseudomonas syringae and Escherichia coli,) and Gram positives (Staphylococcus aureus and Bacillus subtilis). Soil organisms (P. syringae, B. subtilis) and organisms found in the human population (E. coli, S. aureus) are both used to demonstrate the general applicability of clay involvement. Fluorescent images of the biofilms are acquired by staining with propidium iodide, a component of the BacLightTM Live/Dead bacterial viability staining kit (Molecular Probes, Eugene, OR). The evolving polysaccharide-rich biofilm reacts with the clay interlayer site causing a complex substitution of the two-water hectorite interlayer with polysaccharide. The result is often a three-peak composite of the (001) x-ray diffraction maxima resulting from polysaccharide-expanded clays and an organic-driven contraction of a subset of the clays in the reaction medium. X-ray diffractograms reveal that the expanded set creates a broad maximum with clay subsets at 1.84 nm and 1.41 nm interlayer spacings as approximated by a least squares double Lorentzian fit, and a smaller shoulder at larger 2q, deriving from a contraction of the interlayer spacing. Washing with chlorox removes organic material from the contracted clay and creates a 1-water hectorite single peak in place of the double peak. The clay response can be used as an indirect indicator of biofilm in an environmental system.

  11. Antibacterial Activity of Honey on Cariogenic Bacteria

    OpenAIRE

    Zahra Khamverdi; Fatemeh Ahmadi Motamayel; Mohammad Yusof Alikhani; Seyedeh Sare Hendi

    2013-01-01

    Objective: Honey has antibacterial activity. The aim of this study was to evaluate the antibacterial activity of honey on Streptococcus mutans and Lactobacillus.Materials and Methods: In this in vitro study, solutions containing 0%, 5%, 10%, 20%, 50% and100%(w/v) of natural Hamadan honey were prepared. Each blood (nutrient) agar plate was then filled with dilutions of the honey. The strains of bacteria were inoculated in blood agar for 24 hours at 37oC and were adjusted according to the McFar...

  12. Filamentous bacteria transport electrons over centimetre distances

    DEFF Research Database (Denmark)

    Pfeffer, Christian; Larsen, Steffen

    2012-01-01

    Oxygen consumption in marine sediments is often coupled to the oxidation of sulphide generated by degradation of organic matter in deeper, oxygen-free layers. Geochemical observations have shown that this coupling can be mediated by electric currents carried by unidentified electron transporters across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living, electrical cables add a new dimension to the understanding of interactions in nature and may find use in technology development.

  13. Ethylene-producing bacteria that ripen fruit.

    Science.gov (United States)

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples. PMID:25393892

  14. Genetics in methylotrophic bacteria: Appendix. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lidstrom, M.E.

    1998-09-01

    This research has focused primarily on promoters in Methylobacterium extorquens AM1 and in methanotrophic bacteria. In Methylobacterium extorquens work continued on the moxF promoter. The author constructed chromosomal lacZ fusions of this promoter to avoid the regulation problems of plasmid-borne fragments and has shown that this is regulated normally in the chromosome. She has constructed lacZ fusions to some of the mox genes involved in the synthesis of the cofactor, PQQ, in order to carry out similar analysis of transcription of PQQ genes. The author has continued to isolate mox genes in methanotrophs for the purpose of studying their promoters and transcriptional regulation.

  15. Gut Bacteria in Health and Disease

    OpenAIRE

    Eamonn M. M. Quigley

    2013-01-01

    A new era in medical science has dawned with the realization of the critical role of the “forgotten organ,” the gut micro-biota, in health and disease. Central to this beneficial interaction between the microbiota and host is the manner in which bacteria and most likely other microorganisms contained within the gut communicate with the host’s immune system and participate in a variety of metabolic processes of mutual benefit to the host and the microbe. The advent of high-throughput met...

  16. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    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

  17. Dynamic Clustering in Suspension of Motile Bacteria

    CERN Document Server

    Chen, Xiao; Yang, Mingcheng; Zhang, Hepeng

    2015-01-01

    A bacteria suspension exhibits a wide range of collective phenomena arsing from interactions between individual cells. Here we show that Serratia marcescens cells near an air-liquid interface spontaneously aggregate into dynamic clusters through surface-mediated hydrodynamic interactions. These long-lived clusters translate randomly and rotate in the counter-clockwise direction; they continuously evolve, merge with others and split into smaller ones. The observed cluster dynamics is qualitatively reproduced by a numerical model of self-propelled particles that interact via pair-wise forces extracted from hydrodynamic calculations. Bacterial clusters change material and fluid transport near the interface and hence may have environmental and biological consequences.

  18. Bacteria may signal pancreatic cancer risk

    Science.gov (United States)

    A new study finds significant associations between antibodies for multiple oral bacteria and the risk of pancreatic cancer, adding support for the emerging idea that the ostensibly distant medical conditions are related. The study of blood samples from more than 800 European adults, published in the journal Gut, found that high antibody levels for one of the more infectious periodontal bacterium strains of Porphyromonas gingivalis were associated with a two-fold risk for pancreatic cancer. The study was co-led by researchers from Brown University and Harvard University.

  19. Radioactive bacteria target metastatic pancreatic cancer

    Science.gov (United States)

    Researchers at Albert Einstein College of Medicine of Yeshiva University (home of the Albert Einstein Cancer Center) have developed a therapy for pancreatic cancer that uses Listeria bacteria to selectively infect tumor cells and deliver radioisotopes into them. The experimental treatment dramatically decreased the number of metastases (cancers that have spread to other parts of the body) in a mouse model of highly aggressive pancreatic cancer without harming healthy tissue. The study was published in the online edition of the Proceedings of the National Academy of Sciences.

  20. Anger management: bacteria soothe the savage host

    OpenAIRE

    Seed, Patrick C.

    2013-01-01

    A 5-year-old girl has come to you a week after completing a course of antibiotics for a febrile urinary tract infection (UTI). She now seems well and energetic. A urinalysis is now clear without traces of inflammation, including an absence of protein, blood, leukocyte esterase, and nitrites. Her urine is submitted for a test of cure and comes back positive, with over 100,000 colonies per milliliter of E. coli, the same kind of bacteria that was cultured from her urine when she was symptomatic...

  1. Turning bacteria suspensions into a "superfluid"

    CERN Document Server

    López, Héctor Matías; Douarche, Carine; Auradou, Harold; Clément, Eric

    2015-01-01

    The rheological response under simple shear of an active suspension of Escherichia coli is determined in a large range of shear rates and concentrations. The effective viscosity and the time scales characterizing the bacterial organization under shear are obtained. In the dilute regime, we bring evidences for a low shear Newtonian plateau characterized by a shear viscosity decreasing with concentration. In the semi-dilute regime, for particularly active bacteria, the suspension display a "super-fluid" like transition where the viscous resistance to shear vanishes, thus showing that macroscopically, the activity of pusher swimmers organized by shear, is able to fully overcome the dissipative effects due to viscous loss.

  2. Are Bacteria more dangerous in space?

    International Nuclear Information System (INIS)

    With a mission to Mars and a permanent base on the moon as the ultimate dream, space travel is continually pushing back the frontiers. But long space missions present great challenges for science, for example in the field of microbiology. Together with the European Space Agency (ESA), SCK-CEN is studying the effects of space travel conditions on the behaviour of bacteria. In 2009 the SCK-CEN experts completed four innovative research projects at the cutting edge of microbiology, radiation sciences and space travel.

  3. Bacteriophage Infection of Model Metal Reducing Bacteria

    Science.gov (United States)

    Weber, K. A.; Bender, K. S.; Gandhi, K.; Coates, J. D.

    2008-12-01

    Microbially-mediated metal reduction plays a significant role controlling contaminant mobility in aqueous, soil, and sedimentary environments. From among environmentally relevant microorganisms mediating metal reduction, Geobacter spp. have been identified as predominant metal-reducing bacteria under acetate- oxidizing conditions. Due to the significance of these bacteria in environmental systems, it is necessary to understand factors influencing their metabolic physiology. Examination of the annotated finished genome sequence of G. sulfurreducens PCA, G. uraniumreducens Rf4, G. metallireduceans GS-15 as well as a draft genome sequence of Geobacter sp. FRC-32 have identified gene sequences of putative bacteriophage origin. Presence of these sequences indicates that these bacteria are susceptible to phage infection. Polymerase chain reaction (PCR) primer sets designed tested for the presence of 12 of 25 annotated phage-like sequences in G. sulfurreducens PCA and 9 of 17 phage-like sequences in FRC- 32. The following genes were successfully amplified in G. sulfurreducens PCA: prophage type transcription regulator, phage-induced endonuclease, phage tail sheath, 2 phage tail proteins, phage protein D, phage base plate protein, phage-related DNA polymerase, integrase, phage transcriptional regulator, and Cro-like transcription regulator. Nine of the following sequences were present in FRC-32: 4 separate phage- related proteins, phage-related tail component, viron core protein, phage Mu protein, phage base plate, and phage tail sheath. In addition to the bioinformatics evidence, incubation of G. sulfurreducens PCA with 1 ?g mL-1 mytomycin C (mutagen stimulating prophage induction) during mid-log phase resulted in significant cell lysis relative to cultures that remained unamended. Cell lysis was concurrent with an increase in viral like particles enumerated using epifluorescent microscopy. In addition, samples collected following this lytic event (~44hours) were filtered through a 0.22 ? m sterile nylon filter, stained with phosphotungstic acid (PTA), and examined using transmission electron microscopy (TEM). TEM revealed the presence of viral like particles in the culture exposed to mytomycin C. Together these results suggest an active infection with a lysogenic bacteriophage in the model metal reducing bacteria, Geobacter spp., which could affect metabolic physiology and subsequently metal reduction in environmental systems.

  4. Lactic acid bacteria of meat and meat products.

    Science.gov (United States)

    Egan, A F

    1983-09-01

    When the growth of aerobic spoilage bacteria is inhibited, lactic acid bacteria may become the dominant component of the microbial flora of meats. This occurs with cured meats and with meats packaged in films of low gas permeability. The presence of a flora of psychrotrophic lactic acid bacteria on vacuum-packaged fresh chilled meats usually ensures that shelf-life is maximal. When these organisms spoil meats it is generally by causing souring, however other specific types of spoilage do occur. Some strains cause slime formation and greening of cured meats, and others may produce hydrogen sulphide during growth on vacuum-packaged beef. The safety and stability of fermented sausages depends upon fermentation caused by lactic acid bacteria. Overall the presence on meats of lactic acid bacteria is more desirable than that of the types of bacteria they have replaced. PMID:6354082

  5. THE AVAILABILITY OF Mytilus galloprovincialis FOR MONITORING ENTERIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Nüket S?VR?

    2012-01-01

    Full Text Available In this study, the usage of Mediterranean Mussel (Mytilus galloprovincialis Lamarck, 1819 as monitoring organism on enteric bacteria concentrations in heavily polluted marine environments and its use possibilities as water quality improving tool were investigated. The ability of the Mediterranean Mussel to accumulate and purge fecal coliform bacteria investigated in laboratory experiments. First, increase on bacteria concentration was observed on 1,5th hour and sharp decrease rate lasted until 10th hours after that period slow but steady declining bacteria concentration rate was observed and beginning bacteria concentration rate was reached within next 30- 50 hours. Time dependent bacteria concentration reduction has found statistically significant at p<0.001 (r-sq = 0.81. The investigation has also revealed that mussel farming could be established in the over polluted area which is the case only in the different discharge points in the sea.

  6. Rapid, quantitative determination of bacteria in water. [adenosine triphosphate

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.; Thomas, R. R.; Jeffers, E. L.; Deming, J. W. (inventors)

    1978-01-01

    A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are presented so that the light output can be correlated to bacteria in the sample and system noise can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction.

  7. [Ferrous-manganese oxidizing bacteria from the nature water].

    Science.gov (United States)

    Qin, Song-yan; Ma, Fang; Huang, Peng

    2008-06-01

    Glass slides were hanged into a canal to acquire the ferrous-manganese oxidizing bacteria settled bio-film. Two isolated methods for ferrous-manganese oxidizing bacteria with special iron-manganese oxidizing matrix from the bio-film were tested. Element component of bacteria product and sheath structure of bacteria were analyzed. With two methods, plate cultivation and the novel semi-solid in situ cultivation method, strains belong to Family Leptothrix were isolated. XRF showed that the amorphous iron and manganese were two major metal elements of the precipitation formed by one strain of Leptothrix spp.. Through the microscope observation, one strain of Family Leptothrix was determined to form branch-like structured sheath, while another strain formed spider web-like structured sheath. Those isolated bacteria provide model strains for future testing of FISH probe and PCR primer of ferrous-manganese oxidizing bacteria. PMID:18763517

  8. Detection of phenols using engineered bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wise, Arlene A.; Kuske, Cheryl R.; Terwilliger, Thomas C.

    2004-08-10

    Detection of phenols using engineered bacteria. A biosensor can be created by placing a reporter gene under control of an inducible promoter. The reporter gene produces a signal when a cognate transcriptional activator senses the inducing chemical. Creation of bacterial biosensors is currently restricted by limited knowledge of the genetic systems of bacteria that catabolize xenobiotics. By using mutagenic PCR to change the chemical specificity of the Pseudomonas species CF600 DmpR protein, the potential for engineering novel biosensors for detection of phenols has been demonstrated. DmpR, a well-characterized transcriptional activator of the P. CF600's dmp operon mediates growth on simple phenols. Transcription from Po, the promoter heading the dmp operon, is activated when the sensor domain of DmpR interacts with phenol and mono-substituted phenols. By altering the sensor domain of the DmpR, a group of DmpR derivatives that activate transcription of a Po-lacZ fusion in response to eight of the EPA's eleven priority pollutant phenols has been created. The assays and the sensor domain mutations that alter the chemical specificity of DmpR is described.

  9. Detection of phenols using engineered bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wise, Arlene A. (Philadelphia, PA); Kuske, Cheryl R. (Los Alamos, NM); Terwilliger, Thomas C. (Santa Fe, NM)

    2007-12-04

    Detection of phenols using engineered bacteria. A biosensor can be created by placing a reporter gene under control of an inducible promoter. The reporter gene produces a signal when a cognate transcriptional activator senses the inducing chemical. Creation of bacterial biosensors is currently restricted by limited knowledge of the genetic systems of bacteria that catabolize xenobiotics. By using mutagenic PCR to change the chemical specificity of the Pseudomonas species CF600 DmpR protein, the potential for engineering novel biosensors for detection of phenols has been demonstrated. DmpR, a well-characterized transcriptional activator of the P. CF600's dmp operon mediates growth on simple phenols. Transcription from Po, the promoter heading the dmp operon, is activated when the sensor domain of DmpR interacts with phenol and mono-substituted phenols. By altering the sensor domain of the DmpR, a group of DmpR derivatives that activate transcription of a Po-lacZ fusion in response to eight of the EPA's eleven priority pollutant phenols has been created. The assays and the sensor domain mutations that alter the chemical specificity of DmpR is described.

  10. Detection of phenols using engineered bacteria

    Science.gov (United States)

    Wise, Arlene A. (Philadelphia, PA); Kuske, Cheryl R. (Los Alamos, NM); Terwilliger, Thomas C. (Santa Fe, NM)

    2007-12-04

    Detection of phenols using engineered bacteria. A biosensor can be created by placing a reporter gene under control of an inducible promoter. The reporter gene produces a signal when a cognate transcriptional activator senses the inducing chemical. Creation of bacterial biosensors is currently restricted by limited knowledge of the genetic systems of bacteria that catabolize xenobiotics. By using mutagenic PCR to change the chemical specificity of the Pseudomonas species CF600 DmpR protein, the potential for engineering novel biosensors for detection of phenols has been demonstrated. DmpR, a well-characterized transcriptional activator of the P. CF600's dmp operon mediates growth on simple phenols. Transcription from Po, the promoter heading the dmp operon, is activated when the sensor domain of DmpR interacts with phenol and mono-substituted phenols. By altering the sensor domain of the DmpR, a group of DmpR derivatives that activate transcription of a Po-lacZ fusion in response to eight of the EPA's eleven priority pollutant phenols has been created. The assays and the sensor domain mutations that alter the chemical specificity of DmpR is described.

  11. Epidemiology of nosocomial bacteria resistant to antimicrobials

    Directory of Open Access Journals (Sweden)

    Cristina E. Cabrera

    2011-03-01

    Full Text Available Nosocomial infections are a major challenge for public health because of the high rates of morbidity and mortality generated. It was considered that the excessive or inappropriate use of antibiotics triggers the emergence of resistant strains. Among the clinically important bacteria that most commonly cause nososcomial infections, Gram positive multiresistant pathogens stand out such as methicillin-resistant Staphylococcus aureus (MRSA and vancomycin-resistant Enterococcus spp (VRE, and the Gram negative strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp. and Acinetobacter baumannii producing expanded spectrum b-lactamases (ESbL. This review describes the behavior of the main bacterial pathogens resistant to antibiotics that cause infections in Europe, United States, and Latin America, emphasizing studies of molecular epidemiology on a global scale, including the major epidemiological studies in Colombia. The genetic structure of S. aureus and Enterococcus spp strains shows a clonal characteristic favored by the predominance of a small number of clones with the capacity to spread globally, due probably to cross-infection. However, the introduction of MRSA strains from the community encourages genetic diversity, tending to establish a genetic polyclonal endemic structure in places like the United States. In Gram negative bacteria, the high genetic diversity among isolates, mainly in Latin American countries, indicates that the polyclonal spread is influenced by horizontal transfer of plasmids, by excessive exposure to antibiotics, and prolonged hospital stays. In Colombia, there is information on nosocomial resistant pathogens, but molecular epidemiological information is still scarce.

  12. Characterization of cultivable bacteria from brazilian sponges.

    Science.gov (United States)

    Santos-Gandelman, Juliana F; Santos, Olinda C S; Pontes, Paula V M; Andrade, Cleyton Lage; Korenblum, Elisa; Muricy, Guilherme; Giambiagi-Demarval, Marcia; Laport, Marinella S

    2013-12-01

    Among 1,236 colony-forming units (CFU) associated with 11 species of marine sponges collected from a Brazilian coast, a total of 100 morphologically different bacterial strains were analyzed. The phylogenetic diversity of the bacterial isolates was assessed by 16S rRNA gene amplification-restriction fragment length polymorphism (RFLP) analysis, using AluI restriction endonuclease. The RFLP fingerprinting resulted in 21 different patterns with good resolution for the identification of the bacterial isolates at the genus level. The genus Bacillus was the most commonly encountered genus, followed by Kocuria. Regarding the relationship between the morphotypes and species of marine sponges, Mycale microsigmatosa presented major diversity, followed by Dragmacidon reticulatum and Polymastia janeirensis. An antibiotic susceptibility profile of the 100 sponge-associated bacterial strains was determined by the disk diffusion method, and we observed a variable resistance profile, with 15 % of the bacteria being multiresistant. In addition, 71 of 100 strains were able to produce biofilm. These 71 strains were divided into 20 strong biofilm producers, 10 moderate biofilm producers, and 41 weak biofilm producers. The plasmid profile of the 100 bacterial strains was analyzed and 38 (38 %) of these samples possessed one or more plasmids. Studies like this are important to increase the information on these associated bacteria found off the coastline of Brazil, a place which has rich biodiversity that is still unknown. PMID:23925647

  13. Magnetotactic bacteria on Earth and on Mars.

    Science.gov (United States)

    McKay, Christopher P; Friedmann, E Imre; Frankel, Richard B; Bazylinski, Dennis A

    2003-01-01

    Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin. PMID:14577877

  14. Reprogramming of human somatic cells by bacteria.

    Science.gov (United States)

    Ito, Naofumi; Ohta, Kunimasa

    2015-05-01

    In general, it had been believed that the cell fate restriction of terminally differentiated somatic cells was irreversible. In 1952, somatic cell nuclear transfer (SCNT) was introduced to study early embryonic development in frogs. So far, various mammalian species have been successfully cloned using the SCNT technique, though its efficiency is very low. Embryonic stem (ES) cells were the first pluripotent cells to be isolated from an embryo and have a powerful potential to differentiate into more than 260 types of cells. The generation of induced pluripotent stem (iPS) cells was a breakthrough in stem cell research, and the use of these iPS cells has solved problems such as low efficiency and cell fate restriction. These cells have since been used for clinical application, disease investigation, and drug selection. As it is widely accepted that the endosymbiosis of Archaea into eukaryotic ancestors resulted in the generation of eukaryotic cells, we examined whether bacterial infection could alter host cell fate. We previously showed that when human dermal fibroblast (HDF) cells were incorporated with lactic acid bacteria (LAB), the LAB-incorporated HDF cells formed clusters and expressed a subset of common pluripotent markers. Moreover, LAB-incorporated cell clusters could differentiate into cells derived from each of the three germinal layers both in vivo and in vitro, indicating successful reprogramming of host HDF cells by LAB. In the current review, we introduce the existing examples of cellular reprogramming by bacteria and discuss their nuclear reprogramming mechanisms. PMID:25866152

  15. Alternative Ecology of Human Pathogenic Bacteria in Fruits and Vegetables

    OpenAIRE

    Nithya, A.; Gothandam, K. M.; Babu, S.

    2014-01-01

    Outbreaks of illness due to human enteric pathogenic bacteria via fresh vegetables warrant intensive research on changing strategies of these bacteria in alterning their hosts for survival. The systemic infection of human pathogenic bacteria in plants and the plant growth stage at which they establish endophytic relationship is poorly understood. The issue is magnified in countries like India where the dietary habits are changing and consumption of fresh fruits ...

  16. Functional genomics of lactic acid bacteria: from food to health

    OpenAIRE

    Douillard, F.P.; De Vos, W M

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumen...

  17. Isolation of Fucosyltransferase-Producing Bacteria from Marine Environments

    OpenAIRE

    Kajiwara, Hitomi; Toda, Munetoyo; Mine, Toshiki; Nakada,Hiroshi; YAMAMOTO, Takeshi

    2012-01-01

    Fucose-containing oligosaccharides on the cell surface of some pathogenic bacteria are thought to be important for host-microbe interactions and to play a major role in the pathogenicity of bacterial pathogens. Here, we screened marine bacteria for glycosyltransferases using two methods: a one-pot glycosyltransferase assay method and a lectin-staining method. Using this approach, we isolated marine bacteria with fucosyltransferase activity. There have been no previous reports of marine bacter...

  18. Antagonistic Effect of Epiphytic Bacteria from Marine Algae, Southeastern India

    OpenAIRE

    Alex John, A.; Raja, P.; Chellaram, C.; Krithika, S.

    2013-01-01

    Aim of this study was to evaluate the antagonistic potential of epibiotic bacteria from seaweeds, Ulva lactuca, Dictyota dichotoma and Padina tetrastromatica against some potent human pathogens. The epibiotic bacteria of Ulva lactuca shows higher level of inhibition properties than the other species. The strain UL1 shows broad spectrum inhibitory activity against 7 pathogens. The inhibitory level of epibiotic bacteria ranged from low to moderate activity. The present investigation suggests th...

  19. Genetic Elements Associated With Antimicrobial Resistance Among Intestinal Bacteria

    OpenAIRE

    Bita Bakhshi; Nazanin Eftekhari; Mohammad Reza Pourshafie

    2014-01-01

    Background:: Integrons are the major reasons of multidrug resistance (MDR) among enteropathogenic bacteria. Occurrence of horizontal gene transfer between integron-carrying microorganisms and other enteric bacteria may increase the rate of emergence of integron-associated antibiotic resistance. Objectives:: The objective of this study was to investigate class 1 integrons among members of enteropathogenic bacteria isolated from patients in Iran. Materials and Methods:: A total of 120 e...

  20. Feeding of the Nematode Acrobeloides nanus on Bacteria

    OpenAIRE

    Bird, Alan F.; Ryder, Maarten H.

    1993-01-01

    Information on the effect of bacteria-feeding nematodes on bacterial populations in the soil is sparse. We have isolated, cultured, and microscopically examined bacteria and nematodes coexisting within an agricultural soil and have studied their feeding relationship. The bacterium Pseudomonas corrugata isolate 2140R is a biocontrol agent against the pathogenic fungus Gaeumannomyces graminis var. tritici. The nematode Acrobeloides nanus is a cosmopolitan, bacteria-feeding organism widespread i...

  1. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander

    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, the spore forming Bacillus licheniformis 421 and the non-spore forming Pseudomonas putida K12, were used. The core plugs were Stevns Klint outcrop with initial permeability at 2-4 mD. The results revealed that bacteria were able to penetrate and to be transported through the chalk. Furthermore, a higher number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment withB. 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 the permeability to return to initial condition.

  2. Antagonistic Effect of Epiphytic Bacteria from Marine Algae, Southeastern India

    Directory of Open Access Journals (Sweden)

    A. Alex John

    2013-01-01

    Full Text Available Aim of this study was to evaluate the antagonistic potential of epibiotic bacteria from seaweeds, Ulva lactuca, Dictyota dichotoma and Padina tetrastromatica against some potent human pathogens. The epibiotic bacteria of Ulva lactuca shows higher level of inhibition properties than the other species. The strain UL1 shows broad spectrum inhibitory activity against 7 pathogens. The inhibitory level of epibiotic bacteria ranged from low to moderate activity. The present investigation suggests that the epibiotic bacteria are good source for the isolation of antibacterial compounds of biomedical importance. The compounds can further be purified and can used to save mankind from dreadful diseases.

  3. Inactivation of Bacillus spores inoculated in milk by Ultra High Pressure Homogenization.

    Science.gov (United States)

    Amador Espejo, Genaro Gustavo; Hernández-Herrero, M M; Juan, B; Trujillo, A J

    2014-12-01

    Ultra High-Pressure Homogenization treatments at 300 MPa with inlet temperatures (Ti) of 55, 65, 75 and 85 °C were applied to commercial Ultra High Temperature treated whole milk inoculated with Bacillus cereus, Bacillus licheniformis, Bacillus sporothermodurans, Bacillus coagulans, Geobacillus stearothermophilus and Bacillus subtilis spores in order to evaluate the inactivation level achieved. Ultra High-Pressure Homogenization conditions at 300 MPa with Ti = 75 and 85 °C were capable of a spore inactivation of ?5 log CFU/mL. Furthermore, under these processing conditions, commercial sterility (evaluated as the complete inactivation of the inoculated spores) was obtained in milk, with the exception of G. stearothermophilus and B. subtilis treated at 300 MPa with Ti = 75 °C. The results showed that G. stearothermophilus and B. subtilis have higher resistance to the Ultra High-Pressure Homogenization treatments applied than the other microorganisms inoculated and that a treatment performed at 300 MPa with Ti = 85 °C was necessary to completely inactivate these microorganisms at the spore level inoculated (?1 × 10(6) CFU/mL). Besides, a change in the resistance of B. licheniformis, B. sporothermodurans, G. stearothermophilus and B. subtilis spores was observed as the inactivation obtained increased remarkably in treatments performed with Ti between 65 and 75 °C. This study provides important evidence of the suitability of UHPH technology for the inactivation of spores in high numbers, leading to the possibility of obtaining commercially sterile milk. PMID:25084664

  4. Biotechnological applications of acetic acid bacteria.

    Science.gov (United States)

    Raspor, Peter; Goranovic, Dusan

    2008-01-01

    The acetic acid bacteria (AAB) have important roles in food and beverage production, as well as in the bioproduction of industrial chemicals. In recent years, there have been major advances in understanding their taxonomy, molecular biology, and physiology, and in methods for their isolation and identification. AAB are obligate aerobes that oxidize sugars, sugar alcohols, and ethanol with the production of acetic acid as the major end product. This special type of metabolism differentiates them from all other bacteria. Recently, the AAB taxonomy has been strongly rearranged as new techniques using 16S rRNA sequence analysis have been introduced. Currently, the AAB are classified in ten genera in the family Acetobacteriaceae. AAB can not only play a positive role in the production of selected foods and beverages, but they can also spoil other foods and beverages. AAB occur in sugar- and alcohol-enriched environments. The difficulty of cultivation of AAB on semisolid media in the past resulted in poor knowledge of the species present in industrial processes. The first step of acetic acid production is the conversion of ethanol from a carbohydrate carried out by yeasts, and the second step is the oxidation of ethanol to acetic acid carried out by AAB. Vinegar is traditionally the product of acetous fermentation of natural alcoholic substrates. Depending on the substrate, vinegars can be classified as fruit, starch, or spirit substrate vinegars. Although a variety of bacteria can produce acetic acid, mostly members of Acetobacter, Gluconacetobacter, and Gluconobacter are used commercially. Industrial vinegar manufacturing processes fall into three main categories: slow processes, quick processes, and submerged processes. AAB also play an important role in cocoa production, which represents a significant means of income for some countries. Microbial cellulose, produced by AAB, possesses some excellent physical properties and has potential for many applications. Other products of biotransformations by AAB or their enzymes include 2-keto-L-gulonic acid, which is used for the production of vitamin C; D-tagatose, which is used as a bulking agent in food and a noncalorific sweetener; and shikimate, which is a key intermediate for a large number of antibiotics. Recently, for the first time, a pathogenic acetic acid bacterium was described, representing the newest and tenth genus of AAB. PMID:18568850

  5. Polyamine effects on antibiotic susceptibility in bacteria.

    Science.gov (United States)

    Kwon, Dong-Hyeon; Lu, Chung-Dar

    2007-06-01

    Biogenic polyamines (e.g., spermidine and spermine) are a group of essential polycationic compounds found in all living cells. The effects of spermine and spermidine on antibiotic susceptibility were examined with gram-negative Escherichia coli and Salmonella enterica serovar Typhimurium bacteria and clinical isolates of Pseudomonas aeruginosa and with gram-positive Staphylococcus aureus bacteria, including methicillin-resistant S. aureus (MRSA). Exogenous spermine exerted a dose-dependent inhibition effect on the growth of E. coli, S. enterica serovar Typhimurium, and S. aureus but not P. aeruginosa, as depicted by MIC and growth curve measurements. While the MICs of polymyxin and ciprofloxacin were in general increased by exogenous spermine and spermidine in P. aeruginosa, this adverse effect was not observed in enteric bacteria and S. aureus. It was found that spermine and spermidine can decrease the MICs of beta-lactam antibiotics in all strains as well as other types of antibiotics in a strain-dependent manner. Significantly, the MICs of oxacillin for MRSA Mu50 and N315 were decreased more than 200-fold in the presence of spermine, and this effect of spermine was retained when assessed in the presence of divalent ions (magnesium or calcium; 3 mM) or sodium chloride (150 mM). The effect of spermine on the sensitization of P. aeruginosa and MRSA to antibiotics was further demonstrated by population analysis and time-killing assays. The results of checkerboard assays with E. coli and S. aureus indicated a strong synergistic effect of spermine in combination with beta-lactams and chloramphenicol. The decreased MICs of beta-lactams implied that the possible blockage of outer membrane porins by exogenous spermine or spermidine did not play a crucial role in most cases. In contrast, only the MIC of imipenem against P. aeruginosa was increased by exogenous spermine and spermidine, and this resistance effect was abolished in a mutant strain devoid of the outer membrane porin OprD. In E. coli, the MICs of carbenicillin, chloramphenicol, and tetracycline were decreased in two acrA mutants devoid of a major efflux pump, AcrAB. However, retention of the spermine effect on antibiotic susceptibility in two acrA mutants of E. coli suggested that the AcrAB efflux pump was not the target for a synergistic effect by spermine and antibiotics and ruled out the hypothesis of spermine serving as an efflux pump inhibitor in this organism. In summary, this interesting finding of the effect of spermine on antibiotic susceptibility provides the basis for a new potential approach against drug-resistant pathogens by use of existing beta-lactam antibiotics. PMID:17438056

  6. The Effects of Lactic Acid Bacteria and Lactic Acid Bacteria+Enzyme Mixture Silage Inoculants on Maize Silage

    OpenAIRE

    Fi?lya, I?smail

    2002-01-01

    This study was carried out to determine the effects of lactic acid bacteria and lactic acid bacteria+enzyme mixture inoculants as silage additives, on the fermentation, aerobic stability, cell wall content, and in situ rumen degradability of maize (Zea mays) silage. H/M F Inoculant No. 9927 (Medipharm, USA), and Sil-All (Alltech, UK) were used as lactic acid bacteria and lactic acid bacteria+enzyme mixture inoculants. Inoculants were applied to 106cfu g-1 silage levels. Maize was harvested at...

  7. Distribution characteristics of marine bacteria in the China seas

    Directory of Open Access Journals (Sweden)

    Cong MA

    2012-09-01

    Full Text Available Objective?To investigate the main species of marine bacteria and their distribution characteristics in China seas. Methods?Seawater samples were obtained from sea water about one meter below the sea level along the navigation course, and then the bacteria therein were enriched, cultured, identified and tested for drug sensitivity. Results?A total of 528 seawater samples were collected from four seas of China, and 759 marine bacteria in 145 species were isolated. The isolates were mainly Vibro, Enterobacteriaceae, Nonfermenter, Fungi, Pasteurella, Gram positive cocci, Eikenella corrodens and Anaerobic bacteria. Vibrio accounted for 52.9% of the 759 strains of marine bacteria, among which Vibrio alginolyticus, Vibrio fluvialis and Vibrio parahaemolyticus accounted for 75%. There was no significant difference in the quantity of Vibrio alginolyticus, Escherichia coli and Vibrio parahaemolyticus between the 4 sea areas (P=0.071. Chi-square test showed that significant differences existed in the distribution of seven species of marine bacteria among the 4 China seas (P=0.0004. The Gram-positive cocci were isolated more often in Bohai than from other seas; Eikenella corrodens were detected mostly in Yellow Sea; Vibrio were the predominant bacteria in East China sea, up to 70.8%; more Fungi were found in South China sea. The main features of specific bacteria isolated from the four sea areas was higher number of species with less quantity. From North to South, Enterococcus faecalis, Flavobacterium, Vibrio carchariae and C. famata were found to constitute the highest number. Conclusions?In China seas, Vibrios are the dominant bacteria, and the numbers of Anaerobic bacteria and Gram-positive cocci are extremely low. There is a significant difference in the distribution of marine bacteria among 4 China seas.

  8. Energy conversion in Purple Bacteria Photosynthesis

    CERN Document Server

    Caycedo-Soler, Felipe; Quiroga, Luis; Zhao, Guannan; Johnson, Neil F

    2011-01-01

    The study of how photosynthetic organisms convert light offers insight not only into nature's evolutionary process, but may also give clues as to how best to design and manipulate artificial photosynthetic systems -- and also how far we can drive natural photosynthetic systems beyond normal operating conditions, so that they can harvest energy for us under otherwise extreme conditions. In addition to its interest from a basic scientific perspective, therefore, the goal to develop a deep quantitative understanding of photosynthesis offers the potential payoff of enhancing our current arsenal of alternative energy sources for the future. In the following Chapter, we consider the trade-off between dynamics, structure and function of light harvesting membranes in Rps. Photometricum purple bacteria, as a model to highlight the priorities that arise when photosynthetic organisms adapt to deal with the ever-changing natural environment conditions.

  9. Pyrite oxidation by Acidithiobacillus ferrooxidans bacteria

    Directory of Open Access Journals (Sweden)

    Savi? Dragiša S.

    2005-01-01

    Full Text Available The kinetic model of pyrite particle dissolution by the action of bacteria Acidithiobacillus ferrooxidans in a shaken Erlenmeyer flask was presented. The model agreed well with the experimental data for the extracted iron and the number of cells in the liquid phase. The specific growth rate of the adsorbed cells was evaluated (?A = 1,6 d-1 by fitting the experimental data to the model curve. Also, the relevance of the two proposed mechanisms for the bacterial dissolution of sulphide (direct and indirect was discussed, indicating that the indirect one was dominant. The adsorption process of A. ferrooxidans to the pyrite surface was well correlated by a Langmuir type isotherm.

  10. Physical mode of bacteria and virus coevolution

    Science.gov (United States)

    Han, Pu; Niestemski, Liang; Deem, Michael

    2013-03-01

    Single-cell hosts such as bacteria or archaea possess an adaptive, heritable immune system that protects them from viral invasion. This system, known as the CRISPR-Cas system, allows the host to recognize and incorporate short foreign DNA or RNA sequences from viruses or plasmids. The sequences form what are called ``spacers'' in the CRISPR. Spacers in the CRISPR loci provide a record of the host and predator coevolution history. We develop a physical model to study the dynamics of this coevolution due to immune pressure. Hosts and viruses reproduce, die, and evolve due to viral infection pressure, host immune pressure, and mutation. We will discuss the differing effects of point mutation and recombination on CRISPR evolution. We will also discuss the effect of different spacer deletion mechanisms. We will describe population structure of hosts and viruses, how spacer diversity depends on position within CRISPR, and match of the CRISPR spacers to the virus population.

  11. Antimicrobial resistant bacteria in the food chain

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar Technical University of Denmark,

    2003-01-01

    Antimicrobials are used for treatment and prevention of disease in food animals and as feed additives for growth promotion. All uses lead to the development of resistant bacteria, some of which are pathogenic to humans. Current main concerns are with resistance in Salmonella and Campylobacter to fluoroquinolones, which are used for empirical treatment of diarrhea in humans. Resistance to vancomycin and Synercid((R)) in enterococci is associated with use of similar drugs as growth promoters in food animals. Danish food animal producers have terminated the use of antimicrobial growth promoters. This has reduced the total use of antimicrobials by more than 50% and markedly reduced levels of resistance. There is an urgent need to implement globally, WHO principles for prudent use of antimicrobials in food animals. Use of antimicrobials as growth promoters could and should be terminated completely.

  12. Magnetotactic bacteria, magnetosomes and their application.

    Science.gov (United States)

    Yan, Lei; Zhang, Shuang; Chen, Peng; Liu, Hetao; Yin, Huanhuan; Li, Hongyu

    2012-10-12

    Magnetotactic bacteria (MTB) are a diverse group of microorganisms with the ability to orient and migrate along geomagnetic field lines. This unique feat is based on specific intracellular organelles, the magnetosomes, which, in most MTB, comprise nanometer-sized, membrane bound crystals of magnetic iron minerals and organized into chains via a dedicated cytoskeleton. Because of the special properties of the magnetosomes, MTB are of great interest for paleomagnetism, environmental magnetism, biomarkers in rocks, magnetic materials and biomineralization in organisms, and bacterial magnetites have been exploited for a variety of applications in modern biological and medical sciences. In this paper, we describe general characteristics of MTB and their magnetic mineral inclusions, but focus mainly on the magnetosome formation and the magnetisms of MTB and bacterial magnetosomes, as well as on the significances and applications of MTB and their intracellular magnetic mineral crystals. PMID:22579104

  13. Isolation of acetic acid bacteria from honey

    Directory of Open Access Journals (Sweden)

    Wasu Pathom-aree

    2009-02-01

    Full Text Available Four thermotolerant acetic acid bacteria designated as CMU1, CMU2, CMU3 and CMU4 were isolated from six honey samples produced by three native bee species in northern Thailand, namely the dwarf honey bee (Apis florea, Asian honey bee (A. cerena and giant honey bee (A. dorsata. All isolates were tested for their tolerance to acetic acid and ethanol at 30?C and 37?C. It was found that they grew only in a medium containing 1% (v/v acetic acid at 30?C. However, isolate CMU4 showed the highest toleration to ethanol, viz. 10% (v/v and 9% (v/v at 30?C and 37?C respectively. Morphological and biochemical examination indicated that all isolates were members of the genus Gluconobacter.

  14. Exopolysaccharides from sourdough lactic acid bacteria.

    Science.gov (United States)

    Galle, Sandra; Arendt, Elke K

    2014-01-01

    The use of sourdough improves the quality and increases the shelf life of bread. The positive effects are associated with metabolites produced by lactic acid bacteria (LAB) during sourdough fermentation, including organic acids, exopolysaccharides (EPS), and enzymes. EPS formed during sourdough fermentation by glycansucrase activity from sucrose influence the viscoelastic properties of the dough and beneficially affect the texture and shelf life (in particular, starch retrogradation) of bread. Accordingly, EPS have the potential to replace hydrocolloids currently used as bread improvers and meet so the consumer demands for a reduced use of food additives. In this review, the current knowledge about the functional aspects of EPS formation by sourdough LAB especially in baking applications is summarized. PMID:24499068

  15. Dynamics of swimming bacteria at complex interfaces

    CERN Document Server

    Lopez, Diego

    2014-01-01

    Flagellated bacteria exploiting helical propulsion are known to swim along circular trajectories near surfaces. Fluid dynamics predicts this circular motion to be clockwise (CW) above a rigid surface (when viewed from inside the fluid) and counter-clockwise (CCW) below a free surface. Recent experimental investigations showed that complex physicochemical processes at the nearby surface could lead to a change in the direction of rotation, both at solid surfaces absorbing slip-inducing polymers and interfaces covered with surfactants. Motivated by these results, we use a far-field hydrodynamic model to predict the kinematics of swimming near three types of interfaces: clean fluid-fluid interface, slipping rigid wall, and a fluid interface covered by incompressible surfactants. Representing the helical swimmer by a superposition of hydrodynamic singularities, we first show that in all cases the surfaces reorient the swimmer parallel to the surface and attract it, both of which are a consequence of the Stokes dip...

  16. Degradation of multiwall carbon nanotubes by bacteria

    International Nuclear Information System (INIS)

    Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14C-labeled MWCNTs into 14CO2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14C-labeled multiwall carbon nanotubes can be degraded to 14CO2 and other byproducts by a bacteria community under natural conditions

  17. Bioactive proteins against pathogenic and spoilage bacteria

    Directory of Open Access Journals (Sweden)

    Mahmoud Z. Sitohy

    2014-10-01

    Full Text Available Background: It is likely that both human nutrition and the nutrition of livestock are benefited by the presence of bioactive proteins within their respective diet regimes. Bioactive proteins have been defined as specific protein fragments that positively impact bodily functions or conditions and may, ultimately, influence overall human health. The ingestion of bioactive proteins may have an effect on the major body systems—namely, the cardiovascular, digestive, immune and nervous systems. According to their functional properties, bioactive proteins may be classified as antimicrobial, antithrombotic, antihypertensive, opioid, immune-modulatory, mineral binding and anti-oxidative. There are many examples of biologically active food proteins and active peptides that can be obtained from various food protein sources. They have a physiological significance beyond the pure nutritional requirements; in other wordsthey have the acquisition of nitrogen for normal growth and maintenance. Objective: This study aims to specify and characterize the extent and mode of action of bioactive proteins in their native form, (glycinin, glycinin basic sub-unit and ?-conglycinin against specific main pathogens (Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serovar Enteritidis. We will be using standard media while identifying the main constituents responsible for this action. Methods: Glycinin, basic sub-unit and ?-conglycinin were isolated from soybean protein and tested for their antimicrobial action against pathogenic and spoilage bacteria, They were thencompared to the properties of penicillin. Methylated soybean protein and also methylated chickpea protein (MSP and MCP, with isoelectric points around pI 8, were prepared by esterifying. 83 % of their free carboxyl groups and their interactions with Gram positive and Gram negative bacteria were examined. Results: The three divisions of cationic proteins exhibited antibacterial activities equivalent to or higher than the activity of penicillin, with the basic sub-unit exhibiting the highest activity, followed by glycinin.; ?-conglycinin exhibited the lowest level of activity with a MIC of 50, 100 and 1000 ?g/mL, respectively. The IC50% values of the basic subunit, glycinin and ?-conglycinin, against Listeria monocytogenes, were 15, 16 and 695 ?g/mL; against Bacillus subtilis the values were 17, 20, and 612 ?g/mL; and against Salmonella Enteritidis the values were 18, 21 and 526 ?g/mL, respectively. Transmission electron microscopy images of L. monocytogenes and S. Enteritidis exhibited an increase in cell size and a separation of the cell wall from the cell membrane when treated with glycinin or basic sub-unit. The scanning electron microscopy of B. subtilis indicated signs of an irregular, wrinkled outer surface as well as the fragmentation, adhesion, and aggregation of damaged cells or cellular debris when treated with glycinin or the basic subunits; however not with penicillin. The proliferation of L. monocytogenes, S. Enteritidis and Escherichia coli O157:H7-when artificially inoculated in raw milk ,stored at 4 or 25 °C was significantly (P<0·05 reduced by the glycinin sub-unit and nisin (0·5% w/v; but they were only slightly reduced by ?-conglycinin and moderately reduced by lysozyme. The two substances (MSP and MCP exhibited a concentration-dependent inhibitory action against two of the studied bacteria with a minimum inhibitory concentration of approximately 100 µg/mL. The supplementation of raw milk with esterified legume proteins (MSP and MCP has significantly (p < 0.05 reduced the levels of TBC, PBC and PSC in raw milk stored at a temperature of 4 °C. This potentially will delaythe onset of spoilage of by four days. Conclusion: Both glycinin and the basic sub-unit have a more swift antimicrobial action than that of penicillin. Basic sub-units exhibited the highest efficiency at killing bacterial cells, followed by glycinin, penicillin and ?-conglycinin-with the lowest effect; while the bacteria most susceptible to the

  18. Methods and Techniques of Sampling, Culturing and Identifying of Subsurface Bacteria

    International Nuclear Information System (INIS)

    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

  19. Inaktivierungsmechanismen von Geobacillus und Bacillus Sporen während der thermischen Hochdrucksterilisation

    OpenAIRE

    Mathys, Alexander

    2008-01-01

    High pressure thermal sterilization is an emerging technology that can produce uniform, minimally processed foods of high quality, better than heat treatment alone. At present, it has not yet been successfully introduced into the food industry, possibly due to the less known inactivation mechanism of high resistant bacterial spores. This study developed and used new analytical tools, to improve the understanding of spore mechanisms at high pressures and temperatures. Biophysical analyses show...

  20. Atypical bacteria accompanying the scallop Argopecten purpuratus / Bacterias atípicas en el ostión Argopecten purpuratus

    Scientific Electronic Library Online (English)

    Jenny, Llanos; Marianella, Cid; Sara, Navarro; Alejandro, Dinamarca; Patricio, García-Tello.

    Full Text Available Se realizó un análisis sencillo de la bacterioflora cultivable acompañante de diferentes regiones del cuerpo del ostión Argopecten purpuratus la cual se mostró compuesta de bacterias atípicas para la columna de agua. Se presentó un número alto de cepas de Vibrio, coccus Gram-positivos y formadoras d [...] e esporas. También fueron aisladas cepas de la familia Enterobacteriaceae Abstract in english A simple bacteriological analysis for accompanying culturable microflora from different regions of the body of Argopecten purpuratus showed a rather atypical bacteria considering that farming is done in the sea-water column. High numbers of Vibrio strains, Gram-positive cocci, and sporeformers were [...] present. Also members of the Enterobacteriaceae family were isolated

  1. Fermentation of Fructooligosaccharides by Lactic Acid Bacteria and Bifidobacteria†

    OpenAIRE

    Kaplan, Handan; Hutkins, Robert W.

    2000-01-01

    Lactic acid bacteria and bifidobacteria were screened of their ability to ferment fructooligosaccharides (FOS) on MRS agar. Of 28 strains of lactic acid bacteria and bifidobacteria examined, 12 of 16 Lactobacillus strains and 7 of 8 Bifidobacterium strains fermented FOS. Only strains that gave a positive reaction by the agar method reached high cell densities in broth containing FOS.

  2. Isolation of Sulfate-Reducing Bacteria from Human Thoracoabdominal Pus

    OpenAIRE

    Loubinoux, Julien; Jaulhac, Benoit; Piemont, Yves; Monteil, Henri; Le Faou, Alain E.

    2003-01-01

    To evaluate the prevalence of sulfate-reducing bacteria in septic processes, we searched for these bacteria by culture in 100 consecutive abdominal and pleural pus specimens. Twelve isolates were obtained from abdominal samples and were identified by a multiplex PCR as Desulfovibrio piger (formerly Desulfomonas pigra) (seven strains), Desulfovibrio fairfieldensis (four strains), and Desulfovibrio desulfuricans (one strain).

  3. Rapid and simple cryopreservation of anaerobic ammonium-oxidizing bacteria.

    Science.gov (United States)

    Heylen, Kim; Ettwig, Katharina; Hu, Ziye; Jetten, Mike; Kartal, Boran

    2012-04-01

    A quick and simple protocol for long-term cryopreservation of anaerobic ammonium-oxidizing bacteria (anammox bacteria) was developed. After 29 weeks of preservation at -80°C, activity recovery for all tested cultures under at least one of the applied sets of preservation conditions was observed. Growth recovery was also demonstrated for a single-cell culture of "Candidatus Kuenenia stuttgartiensis." PMID:22307300

  4. Rapid and Simple Cryopreservation of Anaerobic Ammonium-Oxidizing Bacteria

    OpenAIRE

    Heylen, Kim; Ettwig, Katharina; Hu, Ziye; Jetten, Mike; Kartal, Boran

    2012-01-01

    A quick and simple protocol for long-term cryopreservation of anaerobic ammonium-oxidizing bacteria (anammox bacteria) was developed. After 29 weeks of preservation at ?80°C, activity recovery for all tested cultures under at least one of the applied sets of preservation conditions was observed. Growth recovery was also demonstrated for a single-cell culture of “Candidatus Kuenenia stuttgartiensis.”

  5. Petrifilm plates for enumeration of bacteria counts in goat milk

    Science.gov (United States)

    PetrifilmTM Aerobic Count (AC) and Coliform Count (CC) plates were validated against standard methods for enumeration of coliforms, total bacteria, and psychrotrophic bacteria in raw (n = 39) and pasteurized goat milk (n = 17) samples. All microbiological data were transformed into log form and sta...

  6. Structurally altered capsular polysaccharides produced by mutant bacteria

    Science.gov (United States)

    Kern, Roger G. (Inventor); Petersen, Gene R. (Inventor); Richards, Gil F. (Inventor)

    1995-01-01

    Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom.

  7. Dynamic self-assembly of motile bacteria in liquid crystals.

    Science.gov (United States)

    Mushenheim, Peter C; Trivedi, Rishi R; Tuson, Hannah H; Weibel, Douglas B; Abbott, Nicholas L

    2014-01-01

    This paper reports an investigation of dynamical behaviors of motile rod-shaped bacteria within anisotropic viscoelastic environments defined by lyotropic liquid crystals (LCs). In contrast to passive microparticles (including non-motile bacteria) that associate irreversibly in LCs via elasticity-mediated forces, we report that motile Proteus mirabilis bacteria form dynamic and reversible multi-cellular assemblies when dispersed in a lyotropic LC. By measuring the velocity of the bacteria through the LC (8.8 ± 0.2 ?m s(-1)) and by characterizing the ordering of the LC about the rod-shaped bacteria (tangential anchoring), we conclude that the reversibility of the inter-bacterial interaction emerges from the interplay of forces generated by the flagella of the bacteria and the elasticity of the LC, both of which are comparable in magnitude (tens of pN) for motile Proteus mirabilis cells. We also measured the dissociation process, which occurs in a direction determined by the LC, to bias the size distribution of multi-cellular bacterial complexes in a population of motile Proteus mirabilis relative to a population of non-motile cells. Overall, these observations and others reported in this paper provide insight into the fundamental dynamic behaviors of bacteria in complex anisotropic environments and suggest that motile bacteria in LCs are an exciting model system for exploration of principles for the design of active materials. PMID:24652584

  8. Use of thermophilic bacteria for bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    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 identifi mechanisms of bioremediation are identified

  9. Glass bead transformation method for gram-positive bacteria

    OpenAIRE

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2009-01-01

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

  10. Glass bead transformation method for gram-positive bacteria

    Directory of Open Access Journals (Sweden)

    Pongsak Rattanachaikunsopon

    2009-12-01

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

  11. Glass bead transformation method for gram-positive bacteria

    Scientific Electronic Library Online (English)

    Pongsak, Rattanachaikunsopon; Parichat, Phumkhachorn.

    2009-12-01

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

  12. Isolation of Crude Oil from Polluted Waters Using Biosurfactants Pseudomonas Bacteria: Assessment of Bacteria Concentration Effects

    OpenAIRE

    Khalifeh, A.; Roozbehani, B.; Moradi, A. M.; Imani Moqadam, S.; Mirdrikvand, M.

    2013-01-01

    Biological decomposition techniques and isolation of environmental pollutions using biosurfactants bacteria are effective methods of environmental protection. Surfactants are amphiphilic compounds that are produced by local microorganisms and are able to reduce the surface and the stresses between surfaces. As a result, they will increase solubility, biological activity, and environmental decomposition of organic compounds. This study analyzes the effects of biosurfactants on crude oil recove...

  13. A porous silicon optical microcavity for sensitive bacteria detection

    International Nuclear Information System (INIS)

    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.

  14. 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.

  15. Enumeration and identification of bacteria in chicken semen.

    Science.gov (United States)

    Reiber, M A; McInroy, J A; Conner, D E

    1995-05-01

    Three experiments were conducted to determine the bacteriological quality of chicken semen. Semen was collected from donor males, diluted, and surface inoculated onto seven different bacteriological media, from which randomly selected colonies were identified. Bacterial counts in semen averaged 5.14 log10 cfu/mL. Tryptic soy agar (TSA) was the best medium for the isolation of Gram-positive bacteria, whereas TSA + .3% bile salts (TSABS) and violet red bile agar + 1% glucose (VRBAG) were the best media for the isolation of Gram-negative and enteric bacteria. The genera of bacteria that were isolated depended on the medium that was used for isolation. The most frequently isolated genera included Escherichia, Staphylococcus, Micrococcus, Enterococcus, and Salmonella. Most of the bacteria that were isolated were endemic to poultry and were common environmental bacteria. This indicates that the environment and feed are important sources of bacterial contamination in broilers. PMID:7603955

  16. Molecular Detection of Endophytic Bacteria on Plantlet Tissue of Sugarcane

    Directory of Open Access Journals (Sweden)

    WIWIK EKO WIDAYATI

    2007-12-01

    Full Text Available Endophytic bacteria live in plant host tissues without causing any symptoms. The aim of this study was to examine the indigenous endophytic bacteria on sugarcane plantlets produced from the young leaf cells by using tissue culture techniques. To detect the existence of endophytic bacteria in the plantlet tissue, a series of molecular method based on PCR were applied by using ribosomal intergenic spacer (RIS primer followed by 16S rDNA partial sequence and single strand conformation polymorphism (SCCP. The results showed that the molecular method could detect the existence of bacteria in the tissues. Using the same methods, the bacteria were also found in other developmental stages of sugarcane (explants, differentiated tissues and callus.

  17. Type IV pili mediated ``walking'' motility of bacteria

    Science.gov (United States)

    Gibiansky, Maxsim; Conrad, Jacinta; Gordon, Vernita; Motto, Dominick; Jin, Fan; Shrout, Joshua; Wong, Gerard

    2010-03-01

    We develop image recognition and particle tracking algorithms to identify and track large numbers of surface-associated bacteria, up to ˜800 cells for up to 6 hours. To characterize the pili-dependent motility mechanisms, we image wild type (WT) and flagella-deficient (pilA) knockout strains of P. aeruginosa. In the pilA strain, we observe two motility mechanisms: a novel ``walking'' mechanism, characterized by bacteria orienting themselves normal to the surface, and a ``crawling'' mechanism, characterized by the bacteria lying flat on the surface. We find that ``crawling'' bacteria move along their long axis and maintain their orientation over time, whereas ``walking'' bacteria change direction rapidly, allowing them to sample microenvironments more efficiently. We also observe both ``walking'' and ``crawling'' in the WT strain, suggesting that flagella do not interfere with these mechanisms of Type-IV pili based motility.

  18. Culturable bacteria in Himalayan ice in response to atmospheric circulation

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2006-06-01

    Full Text Available Only recently has specific attention been given to culturable bacteria in Tibetan glaciers, but their relation to atmospheric circulation is less understood yet. Here we investigate the seasonal variation of culturable bacteria preserved in a Himalayan ice core. High concentration of culturable bacteria in glacial ice deposited during the pre-monsoon season is attributed to the transportation of continental dust stirred up by the frequent dust storms in Northwest China during spring. This is also confirmed by the spatial distribution of culturable bacteria in Tibetan glaciers. Culturable bacteria deposited during monsoon season are more diverse than other seasons because they derive from both marine air masses and local or regional continental sources. We suggest that microorganisms in Himalayan ice can be used to reconstruct atmospheric circulation.

  19. Sensitivity of certain bacteria to antibiotics and irradiation

    International Nuclear Information System (INIS)

    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 ?g/ml respectively. The results indicated that doses of 0.2 kGy and 0.1 ?g/ml reduced the ability of the bacteria for multiplication. (author)

  20. Influence of disturbances on bacteria level in an operating room

    DEFF Research Database (Denmark)

    Brohus, Henrik; Hyldig, Mikkel

    2008-01-01

    In operating rooms great effort is manifested to reduce the bacteria level in order to decrease the risk of infections. The main source of bacteria is the staff and the patient, thus, the resulting bacteria concentration is roughly speaking a combination of the ventilation system and the emission from the occupants. This study investigates the influence of two main disturbances in an operating room namely the door opening during the operation and the activity level of the staff. It is found that the frequent door opening in this case does not cause significant transport of air from outside the operating room to the wound area of the patient. However, a significant influence of the activity level on the bacteria emission and concentration is found. Counting the number of persons in an operating room to estimate the bacteria source strength is not sufficient, the corresponding activity level must be considered, too.

  1. Viability of bacteria in dental calculus - A microbiological study

    Directory of Open Access Journals (Sweden)

    Moolya Nikesh

    2010-01-01

    Full Text Available Aim: The aim of this study was (1 To investigate the viability of bacteria within supragingival and subgingival calculus, (2 To examine motility of bacteria, and (3 To identify bacterial morphotypes in calculus. Materials and Methods: Supra and subgingival calculus were harvested from 30 subjects having clinical evidence of chronic inflammatory periodontal disease and were divided into two groups . Samples from both groups were immediately transported to the Department of Microbiology for gram staining, acridine orange staining, bacterial culture and to the Department of Oral Pathology for dark field microscopy. Results: Gram staining revealed presence of bacteria within the samples. Dark field microscopic examination revealed presence of filamentous organisms, spirochetes, and motile short bacilli. Acridine orange fluorescent stain showed that the viable bacteria appeared apple green. Bacterial culture revealed presence of a variety of aerobic organisms. Conclusion: From the results, it appeared that viable bacteria were present within calculus especially within internal channels and lacunae.

  2. High resistance of some oligotrophic bacteria to ionizing radiation

    International Nuclear Information System (INIS)

    The resistance of seven cultures of eutrophic and oligotrophic bacteria to gamma radiation (at doses up to 360 Gy) was investigated. The bacteria under study were divided into three groups according to their survival ability after irradiation. Methylobacterium organophilum and open-quotes Pedodermatophilus halotoleransclose quotes (LD50 = 270 Gy) were highly tolerant. By their tolerance, these organisms approached Deinococcus radiodurans. Aquatic ring-shaped (toroidal) bacteria Flectobacillus major and open-quotes Arcocella aquaticaclose quotes (LD5 = 173 and 210 Gy, respectively) were moderately tolerant. Eutrophic Pseudomonas fluorescens and Escherichia coli (LD50 = 43 and 38 Gy, respectively) were the most sensitive. X-ray microanalysis showed that in tolerant bacteria the intracellular content of potassium increased and the content of calcium decreased after irradiation. No changes in the element composition of the eutrophic bacterium E. coli were detected. Possible mechanisms of the resistance of oligotrophic bacteria to gamma radiation are discussed

  3. Studies on Bacteria?Like Particles Sampled from the Stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wainwright, M; Weber, P; Smith, J; Hutcheon, I; Klyce, B; Wickramasinghe, N; Narlikar, J; Rajaratnam, P

    2004-07-16

    Bacteria-like particles recovered from the stratosphere and deposited on cellulose acetate membranes have been analyzed to confirm their bacterial nature. One particle appeared to be attached to an inorganic particle apparently by mucoid material typically produced by bacteria. A filamentous structure, morphologically similar to a fungal hypha, was also observed. EDS analysis showed that the particles were all non-mineral and therefore could be biological in nature. However, the composition several clumps of nanobacteria-sized particles were found, by SIMS analysis, to be inconsistent with that of bacteria. The results show that it is dangerous to assume that bacteria-like particles seen under scanning electron microscopy are necessarily bacteria.

  4. COMPARISON OF OCCURENCE LACTIC ACID BACTERIA IN CHOSEN YOGURTS

    Directory of Open Access Journals (Sweden)

    Silvia Pinterová

    2010-11-01

    Full Text Available The yogurt is healthy food, which contains at least 100 million cultures per gram. Probiotic bacteria have been proven to reduce the effects of some gastrointestinal problems, probiotics can greatly reduce lactose intolerance, have also been proven to prevent colon cancers, there are also a natural immune system booster. In our research we detected numbers of lactid acid bacteria in yogurts in slovak market. There were classical yogurts, yogurts with probiotics, yogurts with fat and non fat. We numbered lactid acid bacteria from and after expiration, in agars MRS and Lee´s. In examined yogurts we detected from expiration from 78.107  to 169.107  and after expiration from 59.107 to 133.107 lactic acid bacteria in 1 ml of yogurt. In agreement with Food Codex of SR (2010 of rules all these yogurts satisfy number of lactid acid bacteria. doi:10.5219/31

  5. Purification for eutrophic lake water with immobilized nitrogen cycle bacteria

    International Nuclear Information System (INIS)

    For purification of eutrophic lake water, immobilized nitrogen cycle bacteria (nitrobacteria-denitrifying) made from radiation copolymerization at low temperatures by means of glass forming monomers, i.e. 2-hydroxyethyl acrylate (HEA) and polyethylene glycol dimethacrylate (14 G) were used. The Sequencing Batch Reactors (SBR) system and cell growths of nitrogen cycle bacteria techniques were carried out in order to treat eutrophic lake water. The results showed that the removal efficiencies for total N(TN), NH4+-N and COD with immobilized nitrogen cycle bacteria were 75%, 91.5% and 75% respectively. The results demonstrated that the optimum temperature of immobilized nitrogen cycle bacteria system was 28 degree C. Immobilized nitrogen cycle bacteria system was more resistance to low temperature (10 degree C). The dissolved oxygen (DO) concentrations have effect on removal efficiencies for TN

  6. 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.

  7. 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.

  8. DEVELOPMENT OF TOFU PRODUCTION METHOD WITH PROBIOTIC BACTERIA ADDITION

    Directory of Open Access Journals (Sweden)

    Dorota Zieli?ska

    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 ?OCK 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.

  9. Armpits, Belly Buttons and Chronic Wounds: The ABCs of Our Body Bacteria

    Science.gov (United States)

    ... and Chronic Wounds: The ABCs of Our Body Bacteria By Alisa Machalek and Allison MacLachlan Posted April ... treating skin and other conditions. Chronic Wounds and Bacteria Bacteria from human skin grown on agar in ...

  10. capillare contra bacterias patógenas de peces

    Directory of Open Access Journals (Sweden)

    Pilar Negrete Redondo

    2006-01-01

    Full Text Available En el presente estudio se comprobó, in vitro, la capacidad del extracto que se obtuvo a partir del alga verde dulce acuícola, Oedogonium capillare, con el propósito de inhibir el crecimiento de 23 diferentes bacterias, tanto patógenas de humanos como de importancia ictiopatogénica, pertenecientes a las familias Pseudomonadaceae, Enterobacteriaceae, Aeromonadacea y Vibrionaceae. Las diferentes cepas bacterianas silvestres se aislaron a partir de peces Carassius auratus, cultivados en granjas acuícolas en Morelos, México; después de su purifi cación se identifi caron mediante la técnica API-20E y API-20NE. Las algas que se recolectaron de los estanques para su cultivo se instalaron en el Centro de Investigaciones Biológicas y Acuícolas, en Xochimilco. Secas y homegeneizadas, las algas se sometieron a dos extracciones con hexano a temperatura de refl ujo; la segunda extracción se realizó con una columna cromatrográfi ca de sílica gel y cloroformo etílico. Con el fi n de determinar la sensibilidad de las bacterias a la actividad del extracto, se instrumentó el sistema estandarizado de pruebas de difusión discos. Se impregnaron discos de papel fi ltro con el extracto obtenido del alga O. capillare y con antibióticos comerciales de mayor uso en la acuicultura: kanamicina, cloranfenicol y tetraciclina. Se efectuó la técnica de lisis alcalina para la extracción de plásmidos-R a fi n de determinar su presencia en las cepas. Todo el experimento se replicó mediante cepas bacterianas de la American Type Culture Colection. Se comparó el comportamiento como antibacterial de O. capillare con cada uno de los antibióticos comerciales descritos, por medio de un análisis de correlación. Se obtuvieron altos coefi cientes de correlación entre la forma de actuar del extracto del alga y los antibióticos empleados en este estudio. La actividad antibacterial de O. capillare está más relacionada con la kanamicina que con los otros dos antibióticos. En todas las cepas de colección se registró mayor actividad antibacteriana del extracto, el promedio de los diámetros de los halos de inhibición de las especies de las cuatro familias bacterianas de este grupo fue mayor que los del grupo silvestre, posiblemente debido a la presencia de plásmidos-R en este último grupo.

  11. Precipitation of technetium by subsurface sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    To study the interaction between Tc and subsurface bacteria, we conducted batch experiments with soil and groundwater or sterilized deionized water. The system water/soil was amended with lactate and phosphate for bacterial growth. Nitrate and sulfate were added to stimulate the growth of indigenous denitrifying and sulfate-reducing bacteria. During denitrification Tc-concentration did not change with time. In the presence of sulfate-reducing bacteria, Tc-concentrations decreased in reacted waters which could be attributed to Tc(VII) reduction and precipitation of TcO2 and/or TcS2. Coprecipitation with newly formed iron sulfide is expected to contribute to Tc removal. Additional experiments with U and Tc showed that these elements were simultaneously reduced by sulfate-reducing bacteria. This work shows that 1) subsurface mixed cultures of denitrifying bacteria do not remove Tc from solution, this is different from uranium and 2) sulfate-reducing bacteria reduce and remove Tc from aqueous solutions and thus in situ bioremediation of subsurface waters and soils may be possible with such ubiquitous bacteria. (orig.)

  12. Thermophilic, lignocellulolytic bacteria for ethanol production: current state and perspectives

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

    Lignocellulosic biomass contains a variety of carbohydrates, and their conversion into ethanol by fermentation requires an efficient microbial platform to achieve high yield, productivity, and final titer of ethanol. In recent years, growing attention has been devoted to the development of cellulolytic and saccharolytic thermophilic bacteria for lignocellulosic ethanol production because of their unique properties. First of all, thermophilic bacteria possess unique cellulolytic and hemicellulolytic systems and are considered as potential sources of highly active and thermostable enzymes for efficient biomass hydrolysis. Secondly, thermophilic bacteria ferment a broad range of carbohydrates into ethanol, and some of them display potential for ethanologenic fermentation at high yield. Thirdly, the establishment of the genetic tools for thermophilic bacteria has allowed metabolic engineering, in particular with emphasis on improving ethanol yield, and this facilitates their employment for ethanol production. Finally, different processes for second-generation ethanol production based on thermophilic bacteria have been proposed with the aim to achieve cost-competitive processes. However, thermophilic bacteria exhibit an inherent low tolerance to ethanol and inhibitors in the pretreated biomass, and this is at present the greatest barrier to their industrial application. Further improvement of the properties of thermophilic bacteria, together with the optimization production processes, is equally important for achieving a realistic industrial ethanol production.

  13. Diversity in butane monooxygenases among butane-grown bacteria.

    Science.gov (United States)

    Hamamura, N; Storfa, R T; Semprini, L; Arp, D J

    1999-10-01

    Butane monooxygenases of butane-grown Pseudomonas butanovora, Mycobacterium vaccae JOB5, and an environmental isolate, CF8, were compared at the physiological level. The presence of butane monooxygenases in these bacteria was indicated by the following results. (i) O(2) was required for butane degradation. (ii) 1-Butanol was produced during butane degradation. (iii) Acetylene inhibited both butane oxidation and 1-butanol production. The responses to the known monooxygenase inactivator, ethylene, and inhibitor, allyl thiourea (ATU), discriminated butane degradation among the three bacteria. Ethylene irreversibly inactivated butane oxidation by P. butanovora but not by M. vaccae or CF8. In contrast, butane oxidation by only CF8 was strongly inhibited by ATU. In all three strains of butane-grown bacteria, specific polypeptides were labeled in the presence of [(14)C]acetylene. The [(14)C]acetylene labeling patterns were different among the three bacteria. Exposure of lactate-grown CF8 and P. butanovora and glucose-grown M. vaccae to butane induced butane oxidation activity as well as the specific acetylene-binding polypeptides. Ammonia was oxidized by all three bacteria. P. butanovora oxidized ammonia to hydroxylamine, while CF8 and M. vaccae produced nitrite. All three bacteria oxidized ethylene to ethylene oxide. Methane oxidation was not detected by any of the bacteria. The results indicate the presence of three distinct butane monooxygenases in butane-grown P. butanovora, M. vaccae, and CF8. PMID:10508093

  14. [The rise of resistant gram-negative bacteria].

    Science.gov (United States)

    Kuijper, Ed J; van Dissel, Jaap T

    2010-01-01

    During the past few years there has been a global spread of resistant gram-negative bacteria that are insensitive to cephalosporins and carbapenems. Extended spectrum beta-lactamase (ESBL)-producing bacteria are capable of inactivating the newest generation of cephalosporins. It is notable that ESBL-producing bacteria are found predominantly outside the hospital situation in the environment, in food and in meat products, which leads to the presumption that the food chain is contributing to the rapid spread of these bacteria. Several types of carbapenemase-producing bacteria have been distinguished, of which the 'New Delhi metallo beta-lactamase 1 (NDM-1)' type seems to be prevalent in Asia outside the hospital situation in the community, and is now being transmitted to other continents as a result of migration and tourism. With the rise of ESBL- and carbapenemase-producing gram-negative bacteria (which are also often resistant to most other antibiotics) comes the very real concern that treatment of infections such as urinary tract infections that are currently simple to treat with common oral antibiotics will be problematic in the future. The widespread use of antibiotics in animal husbandry is an important factor in the problem of antibiotic resistance. Since economic motives are of importance, a coordinated approach from many parties concerned will be necessary, not just from the medical sector but also from the veterinary and agricultural world, and from food producers and pharmaceutical companies to combat the spread of multiresistant gram-negative bacteria effectively. PMID:21118590

  15. Differentiating the growth phases of single bacteria using Raman spectroscopy

    Science.gov (United States)

    Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.

    2014-03-01

    In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during growth of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that growth affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary growth phases. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by growth and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different growth phases is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.

  16. 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 1?g/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. PMID:25813393

  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. Gene structure of Elongation factor Tu from Bacillus stearothermophilus.

    Czech Academy of Sciences Publication Activity Database

    Krásný, Libor; Mesters, J.; Fu?ík, Vladimír; Hilgenfeld, R.; Jonák, Ji?í

    Chevy Chase, MD : Howard Hughes Medical Institute Office of Grants and Special Programs, 1997. s. 32. [1997 Meeting of International Research Scholars. 24.06.1997-27.06.1997, Varšava] Grant ostatní: HHMI(US) 75195-540305

  19. Antibacterial Activity of Honey on Cariogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Zahra Khamverdi

    2013-01-01

    Full Text Available Objective: Honey has antibacterial activity. The aim of this study was to evaluate the antibacterial activity of honey on Streptococcus mutans and Lactobacillus.Materials and Methods: In this in vitro study, solutions containing 0%, 5%, 10%, 20%, 50% and100%(w/v of natural Hamadan honey were prepared. Each blood (nutrient agar plate was then filled with dilutions of the honey. The strains of bacteria were inoculated in blood agar for 24 hours at 37oC and were adjusted according to the McFarland scale (10×10 cfumcl -1. All assays were repeated 10 times for each of the honey concentrations. Data were analyzed by non parametric Chi-Square test. Statistical significance was set at ?=0.05.Results: Significant antibacterial activity was detected for honey on Streptococcus mutans in concentrations more than 20% and on Lactobacillus in 100% concentration (P<0.05.Conclusion: It seems that antibacterial activity of honey could be used for prevention and reduction of dental caries.

  20. Optimizing substrate for sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Microbial sulfate reduction followed by sulfide precipitation effectively removes heavy metals from wastewaters. The substrate in the anaerobic zone in a constructed wetland can be designed to emphasize this removal process. This group of bacteria requires CH2O, P, N, and SO4=, reducing conditions, and pH range of 5-9 (pH=7 is optimum). The objective of this study was to find an inexpensive source of nutrients that would give the best initial production of sulfide and make a good wetland substrate. All tested materials contain sufficient P and N; mine drainage provides sulfate. Thus, tests focused on finding organic material that provides the proper nutrients and does not cause the culture to fall below pH of 5. Among chemical nutrients, sodium lactate combined with (NH4)2HPO4 were the only compounds that produced sulfide after 11 days. Among complex nutrients, only cow manure produced sulfide after 26 days. Among complex carbohydrates, cracked corn and raw rice produced sulfide after 10 days. Most substrates failed to produce sulfide because anaerobic fermentation reduced the pH below 5. Presently, cracked corn is the best candidate for a substrate. Five grams of cow manure produced 0.14 millimole of sulfide whereas 0.1 g of cracked corn produced 0.22 millimole

  1. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology of disease, are used to place the various seafood products in risk categories and to identify areas of concern. It is concluded that the presence of pathogens in molluscs and the growth of Listeria monocytogenes in lightly preserved fish products are hazards which are presently not under control. In order to prevent growth and toxin production by Clostridium botulinum when products are stored at abuse temperature, it is recommended that additional barriers to growth are included in lightly preserved (e.g. cold smoked salmon) and low-heat treated (e.g REPFEDS) products. It is finally pointed out that the Hazard Analysis Critical Control Point (HACCP) system is the preferred strategy in most quality assurance programmes and it is recommended that microbiological criteria are applied only as guidelines in the verification of the HACCP-system - and not for official control purposes. (C) 1997 Elsevier Science Ltd

  2. Lactic acid bacteria from fermented table olives.

    Science.gov (United States)

    Hurtado, Albert; Reguant, Cristina; Bordons, Albert; Rozès, Nicolas

    2012-08-01

    Table olives are one of the main fermented vegetables in the world. Olives can be processed as treated or natural. Both have to be fermented but treated green olives have to undergo an alkaline treatment before they are placed in brine to start their fermentation. It has been generally established that lactic acid bacteria (LAB) are responsible for the fermentation of treated olives. However, LAB and yeasts compete for the fermentation of natural olives. Yeasts play a minor role in some cases, contributing to the flavour and aroma of table olives and in LAB development. The main microbial genus isolated in table olives is Lactobacillus. Other genera of LAB have also been isolated but to a lesser extent. Lactobacillus plantarum and Lactobacillus pentosus are the predominant species in most fermentations. Factors influencing the correct development of fermentation and LAB, such as pH, temperature, the amount of NaCl, the polyphenol content or the availability of nutrients are also reviewed. Finally, current research topics on LAB from table olives are reviewed, such as using starters, methods of detection and identification of LAB, their production of bacteriocins, and the possibility of using table olives as probiotics. PMID:22475936

  3. Contribution of Gut Bacteria to Liver Pathobiology

    Directory of Open Access Journals (Sweden)

    Gakuhei Son

    2010-01-01

    Full Text Available Emerging evidence suggests a strong interaction between the gut microbiota and health and disease. The interactions of the gut microbiota and the liver have only recently been investigated in detail. Receiving approximately 70% of its blood supply from the intestinal venous outflow, the liver represents the first line of defense against gut-derived antigens and is equipped with a broad array of immune cells (i.e., macrophages, lymphocytes, natural killer cells, and dendritic cells to accomplish this function. In the setting of tissue injury, whereby the liver is otherwise damaged (e.g., viral infection, toxin exposure, ischemic tissue damage, etc., these same immune cell populations and their interactions with the infiltrating gut bacteria likely contribute to and promote these pathologies. The following paper will highlight recent studies investigating the relationship between the gut microbiota, liver biology, and pathobiology. Defining these connections will likely provide new targets for therapy or prevention of a wide variety of acute and chronic liver pathologies.

  4. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  5. Intracellular chemical gradients: morphing principle in bacteria

    Directory of Open Access Journals (Sweden)

    Endres Robert G

    2012-09-01

    Full Text Available Abstract Advances in computational biology allow systematic investigations to ascertain whether internal chemical gradients can be maintained in bacteria – an open question at the resolution limit of fluorescence microscopy. While it was previously believed that the small bacterial cell size and fast diffusion in the cytoplasm effectively remove any such gradient, a new computational study published in BMC Biophysics supports the emerging view that gradients can exist. The study arose from the recent observation that phosphorylated CtrA forms a gradient prior to cell division in Caulobacter crescentus, a bacterium known for its complicated cell cycle. Tropini et al. (2012 postulate that such gradients can provide an internal chemical compass, directing protein localization, cell division and cell development. More specifically, they describe biochemical and physical constraints on the formation of such gradients and explore a number of existing bacterial cell morphologies. These chemical gradients may limit in vitro analyses, and may ensure timing control and robustness to fluctuations during critical stages in cell development.

  6. Marine bacteria exploit Euler buckling to turn

    Science.gov (United States)

    Son, Kwangmin; Guasto, Jeffrey S.; Lazarus, Arnaud; Miller, James; Reis, Pedro M.; Stocker, Roman

    2011-11-01

    Important species of marine bacteria were recently discovered to swim in a three-step pattern: they swim forward by rotating a single helical flagellum, then backwards by reversing the flagellar rotation, and finally ``flick'' the flagellum in an off-axis motion, producing a large (~90°) reorientation in the swimming direction. What remains unknown in this elegant, minimalistic swimming pattern are the biomechanics of the flick. Here we present new observations based on high-speed video microscopy to capture the detailed dynamics of the reorientation process in Vibrio alginolyticus. Combining the data with a model of buckling of thin structures, we show that the onset of forward swimming triggers a mechanical instability of the flagellar hook, because the propulsive force exceeds the threshold for Euler buckling. This surprising adaptation, where cells take advantage of the flexibility of the flagellar hook to generate a turn, may represent the evolutionarily cheapest bacterial motility pattern and a highly beneficial solution to foraging in resource-poor marine environments.

  7. Discriminating Bacteria with Optical Sensors Based on Functionalized Nanoporous Xerogels

    Directory of Open Access Journals (Sweden)

    Sabine Crunaire

    2014-06-01

    Full Text Available An innovative and low-cost method is proposed for the detection and discrimination of indole-positive pathogen bacteria. The method allows the non-invasive detection of gaseous indole, released by bacteria, with nanoporous colorimetric sensors. The innovation comes from the use of nanoporous matrices doped with 4-(dimethylamino-cinnamaldehyde, which act as sponges to trap and concentrate the targeted analyte and turn from transparent to dark green, long before the colonies get visible with naked eyes. With such sensors, it was possible to discriminate E. coli from H. alvei, two indole-positive and negative bacteria after seven hours of incubation.

  8. Effect of BCD Plasma on a Bacteria Cell Membrane

    International Nuclear Information System (INIS)

    Abstract Cell membrane rupture is considered to be one of the probable mechanisms for bacterial inactivation using barrier corona discharge (BCD) plasma. In this paper, the effect of the BCD plasma on the Escherichia coli (E. coli) bacteria cell wall was investigated through two analytical methods; Adenosine-5'-triphosphate (ATP) assay and Atomic Force Microscopy (AFM). The ATP assay results indicate an increase in the ATP content of samples which were exposed to the BCD plasma. This implies the bacteria cell rupture. Moreover, AFM images confirm a serious damage of the bacteria cell wall under the influence of the bactericidal agents of the plasma

  9. [Colorless sulfur bacteria Thioploca from different sites in Lake Baikal].

    Science.gov (United States)

    Zemskaia, T I; Chernitsyna, S M; Dul'tseva, N M; Sergeeva, V N; Pogodaeva, T V; Namsaraev, B B

    2009-01-01

    The colorless sulfur bacteria Thioploca spp. found in Lake Baikal are probably a marker for the influx of subterranean mineralized fluids. Bacteria act as a biological filter; by consuming sulfide in their metabolism, they detoxicate it and maintain the purity of Lake Baikal's water. The bacteria were investigated by various techniques. According to analysis of the 16S rRNA gene fragment, Thioploca sp. from Frolikha Bay, Baikal belongs to the clade of freshwater species found in Lake Biwa and Lake Constance; it is most closely related to Thioploca ingrica. PMID:19334606

  10. Heterotrophic bacteria and bacterivorous protozoa in oceanic macroaggregates.

    Science.gov (United States)

    Caron, D A; Davis, P G; Madin, L P; Sieburth, J M

    1982-11-19

    Oceanic macroaggregates (marine snow and Rhizosolenia mats) sampled from the Sargasso Sea are associated with bacterial and protozoan populations up to four orders of magnitude greater than those present in samples from the surrounding water. Filamentous, curved, and spiral bacteria constituted a higher proportion of the bacteria associated with the particles than were found among bacteria in the surrounding water. Protozoan populations were dominated numerically by heterotrophic microflagellates, but ciliates and amoebas were also observed. Macroaggregates are highly enriched heterotrophic microenvironments in the oceans and may be significant for the cycling of particulate organic matter in planktonic food chains. PMID:17771038

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

    DEFF Research Database (Denmark)

    KnØchel, Susanne; Harmsen, Morten

    2008-01-01

    Many gram-positive bacteria are able to form aggregates or biofilms and resist external stress factors and some gram-positive pathogenic bacteria such as Listeria monocytogenes and Bacillus cereus may persist in the food production environment for extended periods. Most research has focussed on the gram-negative bacteria and, in general, less is known abourt the gram poritives. At present much conflicting evidence has been presented perhaps because so many internal and external factors influence the ability to adhere. Some of the present knowledge of biofilm or aggregation forming properties will presented and discussed.

  12. Can soil bacteria solve PCB disposal problems with bioremediation

    International Nuclear Information System (INIS)

    A study headed by scientists at Laval University in Quebec City is designed to turn common soil bacteria into polychlorinated biphenyl (PCB) neutralizers. There are currently four natural enzymes that can give bacteria the power they need to break down 30 or 40 of the 209 compounds which make up PCBs. The objective of this research project is to explore the enzymatic mechanisms that enable bacteria to break down some PCB compounds but not others. The research team hopes to be able to modify the enzymes so that they will be able to degrade many other toxic PCB compounds, and other toxic materials such as polycyclic aromatic hydrocarbons, dioxins and furans. 1 fig

  13. Efficacy of entomopathogenic bacteria for control of Musca domestica.

    Science.gov (United States)

    Zimmer, Cristine R; Dias de Castro, Luciana L; Pires, Sabrina M; Delgado Menezes, Adriane M; Ribeiro, Paulo B; Leivas Leite, Fábio P

    2013-11-01

    The aim of this study was to evaluate the larvicidal activity, and sub lethal effects of entomopathogenic bacteria Brevibacillus laterosporus, Bacillus thuringiensis var. israelensis, B. thuringiensis var. kurstaki, and a commercial formulation of Bacillus sphaericus on Musca domestica. Bacterial suspensions were prepared in different concentrations and added to the diet of newly-hatched larvae which were monitored until the adult stage. The larvae were susceptible to the B. laterosporus, B. thuringiensis var. israelensis, and B. thuringiensis var. kurstaki bacteria in varied concentration levels. These bacteria have larvicidal and sub lethal effects on the development of flies, reducing both adult size, and impairing the reproductive performance of the species. PMID:24018169

  14. Lack of ultraviolet mutagenesis in radiation-resistant bacteria

    International Nuclear Information System (INIS)

    Ultraviolet (UV) radiation did not induce rifampicin-resistant mutants in populations of the taxonomically-related radiation-resistant bacteria Deinococcus radiodurans, D. radiopugnans, D. radiophilus and D. proteolyticus, although such mutants arose spontaneously at a low frequency and at a high frequency after treatment of cultures with N-nitroso compounds. The radiation-resistant bacteria Arthrobacter radiotolerans and P-30-A were also UV-mutable. We conclude that the radiation-resistant bacteria repair UV-induced DNA damage accurately and lack an error-prone pathway for the repair of such damage. (orig.)

  15. Characterization of lactic acid bacteria and other gut bacteria in pigs by a macroarraying method.

    Science.gov (United States)

    Thanantong, Narut; Edwards, Sandra; Sparagano, Olivier A E

    2006-10-01

    Lactic acid bacteria (LAB) consist of many genera, Gram-positive, and nonspore-forming micro-organisms; some members being used as probiotics while some others have negative effects on pig health. Bacterial species in the gastrointestinal tract can produce antibacterial substances, reduce serum cholesterol in their host, or can be responsible for growth reduction, diarrhea, and intestinal epithelial damage. It is therefore important for the pig industry to evaluate the impact of food and farm management on the presence of "good" or "bad" bacteria and the risk for consumers. This articles focuses on the molecular identification of gut microflora species following different diets given to pigs in UK and correlating the data on growth, health, and welfare. First of all, pig feces were individually collected from sows before and after farrowing and also from piglets before and after weaning over several months. Bacteria colonies were grown on MRS agar plates from feces and DNA was extracted (QIAamp DNA stool kit) and amplified using 16S rDNA (27f and 519r) primers. DNA sequencing and sequence alignment allowed us to identify species-specific zones, which were used as probes in a macroarray system also known as reverse line blot hybridization. Some probes were found to be species specific for the following species: Lactobacillus acidophilus, L. animalis, L. gallinarum, L. kitasanotis, L salivarius, Streptococcus alactolyticus, S. hyointestinalis, and Sarcina ventriculi. Actual studies are now focusing on the impact of diets of the microflora in different gut parts and at different stages of the animal's life. PMID:17135526

  16. Antibacterial and Plasmid Curing Activity of Lactic Acid Bacteria against Multidrug Resistant Bacteria Strains

    Directory of Open Access Journals (Sweden)

    Nehal El-Deeb

    2015-01-01

    Full Text Available Multiple Drug Resistance (MDR is a serious health problem and major challenge to global drug discovery programs. Most of the genetic determinants that confer resistance to antibiotics are located on plasmids in bacteria. The present investigation was undertaken to investigate the antibacterial effect and the ability of extra- and intra-cellular extracts of Lactic Acid Bacteria (LAB to cure plasmid acquiring resistance in certain clinical antibiotic-resistant bacterial isolates (Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Shigella sp.. Transformation experiments were carried out using clinical isolates as plasmid donor and Escherichia coli strain HB101 (sensitive to the tested antibiotic, as recipient. Minimal Inhibitory Concentration (MIC of LAB extracts was determined using the microtiter plate method. Plasmid curing activity of LAB extracts was determined by evaluating the inability of bacterial colonies (pre-treated with LAB extract for 18 h to grow in the presence of antibiotics. The physical loss of plasmid DNA in the cured derivatives was further confirmed by agarose gel electrophoresis. The LAB showed antibacterial effect, inhibited up to 90% of bacterial biofilm formation and cured the pathogenic bacteria from plasmids. The presence of plasmid in transformants was confirmed through electrophoresis and the transformants were also tested for each antibiotic resistance already recorded for the donor isolates. Both extracts (extra-and intra-cellular extracts inhibited the growth of the clinical isolates. Extracellular extracts exceeded 90% inhibition on some isolates. The LAB extract mediated plasmid curing resulted in the subsequent loss of antibiotic (Chl, Dox, Ery, Gm, Kaf, Lin and Pen resistance encoded in the plasmids as revealed by antibiotic resistance profile of cured strains. The extracellular extract of LAB may be a source of anti-plasmid (plasmid borne multiple antibiotic resistance agents of natural origin.

  17. Enumeration of lactic acid bacteria on grass and the effects on silage fermentation of added bacteria

    OpenAIRE

    Moran, Joseph

    1990-01-01

    Initial studies on the methodology of enumerating lactic acid bacteria (LAB) on grass and silage indicated that (a) varying the homogenisation time in a stomacher from 1 to 7 minutes did not effect LAB numbers, (b) MRS and Rogosa media gave similar LAB counts in silage and (c) anaerobic incubation of plates led to higher counts of LAB from silage compared to micro-aerophi1ic incubation, but similar counts from grass. A survey of LAB numbers on grass grown for silage sh...

  18. Infecciones por bacterias poco comunes y oncogénesis bacteriana / Infections due to unusual bacteria and bacterial oncogenesis

    Scientific Electronic Library Online (English)

    Horacio A., Lopardo.

    Full Text Available La recuperación de algunos microorganismos de aislamiento esporádico en el laboratorio de microbiología clínica podría significar la existencia de algún defecto inmunitarioespecial en el paciente. Por ejemplo, se ha descrito una importante correlación entre Clostridium septicum y carcinoma de colon, [...] y se han visto relacionadas con leucemias y linfomas a especies que aparecen casi siempre como contaminantes (Bacillus spp., Corynebacterium spp.) y a otras raramente aisladas en otros contextos (Capnocytophaga spp.). Hay bacterias que se aíslan casi exclusivamente de pacientes con sida (Rhodococcus equi). Se ha observado una mayor frecuencia de infecciones por Campylobacter spp., Aeromonas spp. y estreptococos del grupo G y del grupo mitis en individuos con algún tipo de cáncer que en el resto de los pacientes. También hay bacterias que son marcadoras de algún cáncer no detectado o que afectan más a pacientes neutropénicos que a individuos normoinmunes. La alteración de la reacción inflamatoria, la linfoproliferación mediada por antígenos bacterianos y la inducción de hormonas que aumentan la proliferación de las células epiteliales podrían ser causas de la oncogénesis bacteriana. Los ejemplos clásicos son el adenocarcinoma gástrico inducido por Helicobacter pylori, la asociación de la bacteriemia por estreptococos del grupo bovis y el cáncer de colon y los linfomas de tejido linfoide asociado a mucosas (MALT) en vinculación con especies de Helicobacter (MALT gástricos) y con Chlamydophila spp. (MALT oculares). El aislamiento de alguno de estos patógenos debería ser un llamado de atención para inducir al estudio de alguna enfermedad maligna. Abstract in english The recovery of an unusual organism in the clinical microbiology laboratory may be an indicator of an immunological abnormality in the patient. For instance, an important relationship between Clostridium septicum and colon carcinoma as well as between leukemia or lymphoma with species frequently con [...] sidered contaminants (Bacillus spp., Corynebacterium spp.) or others rarely isolated from different contexts (Capnocytophaga spp.) were described. Some bacteria are almost exclusively isolated from AIDS patients (Rhodococcus equi). Campylobacter spp., Aeromonas spp., group G and mitis group streptococci were more frequently isolated in individuals suffering from any type of cancer than in other patients. Furthermore, some other bacteria can be considered markers of an undetected cancer that can be found mostly in neutropenic patients rather than in immunologically normal individuals. Possible mechanisms of bacterial oncogenesis include a modification of the inflammatory response, antigen-derived lymphoproliferation, and induction of hormones that increase epithelial cell proliferation. Typical examples of the above are: gastric adenocarcinoma induced by Helicobacter pylori, the association between group bovis bacteremia and colon carcinoma and the mucosa-associated lymphoid tissue (MALT) related to Helicobacter species (gastric MALT) and Chlamydophila spp. (ocular MALT). Isolation of any of these pathogens should require a thorough search for possible malignant diseases.

  19. Filamentous sulfur bacteria preserved in modern and ancient phosphatic sediments: implications for the role of oxygen and bacteria in phosphogenesis.

    Science.gov (United States)

    Bailey, J V; Corsetti, F A; Greene, S E; Crosby, C H; Liu, P; Orphan, V J

    2013-09-01

    Marine phosphate-rich sedimentary deposits (phosphorites) are important geological reservoirs for the biologically essential nutrient phosphorous. Phosphorites first appear in abundance approximately 600 million years ago, but their proliferation at that time is poorly understood. Recent marine phosphorites spatially correlate with the habitats of vacuolated sulfide-oxidizing bacteria that store polyphosphates under oxic conditions to be utilized under sulfidic conditions. Hydrolysis of the stored polyphosphate results in the rapid precipitation of the phosphate-rich mineral apatite-providing a mechanism to explain the association between modern phosphorites and these bacteria. Whether sulfur bacteria were important to the formation of ancient phosphorites has been unresolved. Here, we present the remains of modern sulfide-oxidizing bacteria that are partially encrusted in apatite, providing evidence that bacterially mediated phosphogenesis can rapidly permineralize sulfide-oxidizing bacteria and perhaps other types of organic remains. We also describe filamentous microfossils that resemble modern sulfide-oxidizing bacteria from two major phosphogenic episodes in the geologic record. These microfossils contain sulfur-rich inclusions that may represent relict sulfur globules, a diagnostic feature of modern sulfide-oxidizing bacteria. These findings suggest that sulfur bacteria, which are known to mediate the precipitation of apatite in modern sediments, were also present in certain phosphogenic settings for at least the last 600 million years. If polyphosphate-utilizing sulfide-oxidizing bacteria also played a role in the formation of ancient phosphorites, their requirements for oxygen, or oxygen-requiring metabolites such as nitrate, might explain the temporal correlation between the first appearance of globally distributed marine phosphorites and increasing oxygenation of Neoproterozoic oceans. PMID:23786451

  20. The contribution of bacteria to algal growth by carbon cycling.

    Science.gov (United States)

    Bai, Xue; Lant, Paul; Pratt, Steven

    2015-04-01

    Algal mass production in open systems is often limited by the availability of inorganic carbon substrate. In this paper, we evaluate how bacterial driven carbon cycling mitigates carbon limitation in open algal culture systems. The contribution of bacteria to carbon cycling was determined by quantifying algae growth with and without supplementation of bacteria. It was found that adding heterotrophic bacteria to an open algal culture dramatically enhanced algae productivity. Increases in algal productivity due to supplementation of bacteria of 4.8 and 3.4 times were observed in two batch tests operating at two different pH values over 7 days. A kinetic model is proposed which describes carbon limited algal growth, and how the limitation could be overcome by bacterial activity to re-mineralize photosynthetic end products. PMID:25312046

  1. Phylogenetic analysis on the soil bacteria distributed in karst forest

    Scientific Electronic Library Online (English)

    JunPei, Zhou; Ying, Huang; MingHe, Mo.

    2009-12-01

    Full Text Available Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representa [...] tive clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria), Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria), Firmicutes (Low G+C Gram-positive bacteria) and candidate divisions (including the SPAM and GN08).

  2. Isolation and identification of conjunctival bacteria in cattle in Mosul

    Directory of Open Access Journals (Sweden)

    H. H. Ali

    2011-01-01

    Full Text Available This study included examination of (120 eye swabs, from cows from different ages and regions in Mosul city. This study extended from September – December 2009. The samples were collected from clinically healthy and infected eyes of animals. 11 bacterial species were isolated they included Staphylococcus spp. 22.4%, Bacillus spp. 18.2%, Corynebacterium 17.6%, Streptococcus spp. 7%, Staphylococcus aureus 8.2%, Moraxella bovis 10.6%, E. coli 5.9%, Pseudomonas spp. 4.7%, Klebsiella spp. 2.4%, Micrococcus spp. 1.8%, Proteus spp. 1.2%. The isolated bacteria were 170, Gram positive bacteria were 128/170 while Gram negative bacteria 42/170 (24.7%. Many types of bacteria isolated from healthy swabs 110 (64.7% and 60 (35.3% from infected swabs.

  3. EFFECT OF SODIUM PHOSPHATES ON SELECTED FOOD GRADE BACTERIA

    Directory of Open Access Journals (Sweden)

    Stanislav Krá?mar

    2011-04-01

    Full Text Available The aim of this study was to examine the inhibitory effect in vitro of selected sodium phosphates (under the corporate names Hexa 68, Hexa 70, Trikrystal, FST, Pyro 52, KPS, Didi on selected gram-positive and gram-negative bacteria. Seven different concentrations of each phosphate were used. Sensitivity of the bacterial strains to phosphates was observed in broth supplemented with salts. In vitro was showed a negative effect of various phosphates on growth of selected gram-positive bacteria. Orthophosphates and diphosphates (pyrophosphates did not have significant inhibitory effect on tested bacteria at neutral pH. With the exception of phosphate Trikrystal has not been found in vitro significant inhibitory effects on gram-negative bacteria.doi:10.5219/141

  4. CHARACTERIZATION OF NATURAL MICROCOSMS OF ESTUARINE MAGNETOTACTIC BACTERIA

    Directory of Open Access Journals (Sweden)

    ALEJANDRO SALAZAR

    2011-01-01

    Full Text Available No se ha reportado ningún estudio completo sobre microcosmos naturales de bacterias magnetotácticas (MTB en estuarios o ambientes tropicales. Además, casi todos los estudios sobre las bacterias magnetotácticas se han desarrollado en aguas dulces alejadas del ecuador. Este trabajo se desarrolla sobre el ecuador y reporta una caracterización mineralógica y fisicoquímica detallada de dos microcosmos bacterianos estuarinos. Los resultados muestran que la lixiviación de minerales en los sedimentos puede ser un factor importante en la solubilización de elementos requeridos por las bacterias magnetotácticas. Específicamente, que el clinocloro, flogopita, nontronita y haloisita pueden estar entre los minerales más importantes en la lixiviación de hierro a los microcosmos estuarinos. Se concluye que la concentración de nitrato en el agua no debe ser tan baja como se ha reportado para lograr un crecimiento bacteriano óptimo. Las bacterias magnetotácticas no necesitan grandes cantidades de hierro disuelto para su crecimiento ni para la síntesis de magnetosomas.

  5. Interactions of bacteria with diatoms: Influence on natural marine biofilms.

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; DeCosta, P.M.; Anil, A.C.; Sawant, S.S.

    2014-01-01

    carried out with natural marine biofilms from a tropical monsoon-influenced environment to evaluate the interactions between bacteria and diatoms through application of antibiotics (streptomycin and chloramphenicol). Overall, chloramphenicol inhibited...

  6. 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.

  7. Anti-Allergic Properties of Lactic Acid Bacteria

    International Science & Technology Center (ISTC)

    Genotyping and Analysis of Lactic Acid Bacteria Isolated from National Sour Milk Produce Included into Functional Nutrition Rations in the Residence Regions of Persons with Active Longevity in the CIS Countries

  8. Small Talk: Cell-to-Cell Communication in Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bassler, Bonnie (Princeton University)

    2008-05-14

    Cell-cell communication in bacteria involves the production, release, and subsequent detection of chemical signaling molecules called autoinducers. This process, called quorum sensing, allows bacteria to regulate gene expression on a population-wide scale. Processes controlled by quorum sensing are usually ones that are unproductive when undertaken by an individual bacterium but become effective when undertaken by the group. For example, quorum sensing controls bioluminescence, secretion of virulence factors, biofilm formation, sporulation, and the exchange of DNA. Thus, quorum sensing is a mechanism that allows bacteria to function as multi-cellular organisms. Bacteria make, detect, and integrate information from multiple autoinducers, some of which are used exclusively for intra-species communication while others enable communication between species. Research is now focused on the development of therapies that interfere with quorum sensing to control bacterial virulence.

  9. [Activity of fusidic acid on strictly anaerobic bacteria].

    Science.gov (United States)

    Canzi, A M; Weber, P; Boussougant, Y

    1987-05-01

    Fusidic acid is a well known antimicrobial agent due to its narrow spectrum of activity against Gram positive bacteria and especially staphylococci. Therefore, it is after used preventively against bacterial infection in traumatology, but the susceptibility of anaerobic bacteria is not well known. We have studied, the in vitro activity of sodium fusidate against 147 strains of anaerobic bacteria. This antibiotic has a moderate activity against Bacteroides, more significant against Clostridium, Peptococcus et Peptostreptococcus; it has no bactericidal activity. Clostridium difficile is different from other anaerobic bacteria because of its slow MIC and its MBC near to its MIC. Fusidic acid could be proposed for the treatment of pseudomembranous and antibiotic-associated colitis induced by Clostridium difficile. PMID:3302863

  10. Impacts of Gut Bacteria on Human Health and Diseases

    Science.gov (United States)

    Zhang, Yu-Jie; Li, Sha; Gan, Ren-You; Zhou, Tong; Xu, Dong-Ping; Li, Hua-Bin

    2015-01-01

    Gut bacteria are an important component of the microbiota ecosystem in the human gut, which is colonized by 1014 microbes, ten times more than the human cells. Gut bacteria play an important role in human health, such as supplying essential nutrients, synthesizing vitamin K, aiding in the digestion of cellulose, and promoting angiogenesis and enteric nerve function. However, they can also be potentially harmful due to the change of their composition when the gut ecosystem undergoes abnormal changes in the light of the use of antibiotics, illness, stress, aging, bad dietary habits, and lifestyle. Dysbiosis of the gut bacteria communities can cause many chronic diseases, such as inflammatory bowel disease, obesity, cancer, and autism. This review summarizes and discusses the roles and potential mechanisms of gut bacteria in human health and diseases. PMID:25849657

  11. Transfer of antibiotic resistant bacteria from animals to man

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar; Aarestrup, Frank MØller

    1999-01-01

    Antibiotic resistance develops in zoonotic bacteria in response to antibiotics used in food animals. A close association exists between the amounts of antibiotics used and the levels of resistance observed. The classes of antibiotics routinely used for treatment of human infections are also used for animals either for therapy or for growth promotion. Antibiotic resistance in zoonotic bacteria constitute a public health hazard, primarily through the increased risk of treatment failures. This paper describes the zoonotic bacteria, salmonella, campylobacter, yersinia and enterohaemorrhagic E. coli (EHEC). Infections with these agents do not generally require antibiotic therapy, but in some cases antibiotics are essential to obtain a successful cure. The levels and types of resistance observed in zoonotic bacteria in some countries, especially the increasing levels of fluoroquinolone resistance in salmonella and campylobacter, gives cause for concern. The principles of controlling resistance development involve infection control at herd level and prudent use of antibiotics.

  12. Extraction and Characterization of Oil Degrading Bacteria

    Directory of Open Access Journals (Sweden)

    Khalida Khan

    2006-01-01

    Full Text Available The present study was conducted to determine the isolation, identification and characterization of efficient oil degrading bacterial strains and to study the effect of different concentration of crude oil on the growth of bacterial strain. Two samples soil and water were collected from the crude oil contaminated areas for the isolation and characterization of efficient crude oil degrading strains. Sub culturing technique was employed to isolate 43 numerically dominant bacteria that had the ability to grow on 1.0% crude oil on nutrient agar plates. The isolates were then subjected to different concentrations of crude oil on nutrient agar, mineral salt agar media containing Phosphorous, Nitrogen and trace elements with glucose (PNTG and without glucose (PER. These isolates showed rich growth on nutrient agar media along with crude oil. Out of 43 isolates 7 were able to grow up to 2.0% crude oil and were named as AA-1 to AA-7. These strains were also able to grow on mineral salt agar media with and without glucose but with different susceptibility to different concentrations of crude oil. Finally 3 prospective strains AA-1, AA-2 and AA-3 were selected for further studies. These strains exhibited good growth in PNTG containing 1.0% crude oil as evident by increase in Optical Density (OD after every 24 h for five days. These isolated strains were identified by morphological and biochemical tests and were found to belong to genus Bacillus. These strains were subjected to shake flask transformation of crude oil in mineral salt media (PNTG with glucose for 15 days. Marked change in crude oil colour was observed for these isolates, indicating their biodegradative ability. These isolated strains were able to use crude oil as the sole source of carbon and energy even under stressed environmental conditions. Thus these strains have bright potential for biodegradation of crude oil resulting in clean up of oil spills.

  13. Improving the biodegradative capacity of subsurface bacteria

    International Nuclear Information System (INIS)

    The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates

  14. Terpene synthases are widely distributed in bacteria

    Science.gov (United States)

    Yamada, Yuuki; Kuzuyama, Tomohisa; Komatsu, Mamoru; Shin-ya, Kazuo; Omura, Satoshi; Cane, David E.; Ikeda, Haruo

    2015-01-01

    Odoriferous terpene metabolites of bacterial origin have been known for many years. In genome-sequenced Streptomycetaceae microorganisms, the vast majority produces the degraded sesquiterpene alcohol geosmin. Two minor groups of bacteria do not produce geosmin, with one of these groups instead producing other sesquiterpene alcohols, whereas members of the remaining group do not produce any detectable terpenoid metabolites. Because bacterial terpene synthases typically show no significant overall sequence similarity to any other known fungal or plant terpene synthases and usually exhibit relatively low levels of mutual sequence similarity with other bacterial synthases, simple correlation of protein sequence data with the structure of the cyclized terpene product has been precluded. We have previously described a powerful search method based on the use of hidden Markov models (HMMs) and protein families database (Pfam) search that has allowed the discovery of monoterpene synthases of bacterial origin. Using an enhanced set of HMM parameters generated using a training set of 140 previously identified bacterial terpene synthase sequences, a Pfam search of 8,759,463 predicted bacterial proteins from public databases and in-house draft genome data has now revealed 262 presumptive terpene synthases. The biochemical function of a considerable number of these presumptive terpene synthase genes could be determined by expression in a specially engineered heterologous Streptomyces host and spectroscopic identification of the resulting terpene products. In addition to a wide variety of terpenes that had been previously reported from fungal or plant sources, we have isolated and determined the complete structures of 13 previously unidentified cyclic sesquiterpenes and diterpenes. PMID:25535391

  15. Terpene synthases are widely distributed in bacteria.

    Science.gov (United States)

    Yamada, Yuuki; Kuzuyama, Tomohisa; Komatsu, Mamoru; Shin-Ya, Kazuo; Omura, Satoshi; Cane, David E; Ikeda, Haruo

    2015-01-20

    Odoriferous terpene metabolites of bacterial origin have been known for many years. In genome-sequenced Streptomycetaceae microorganisms, the vast majority produces the degraded sesquiterpene alcohol geosmin. Two minor groups of bacteria do not produce geosmin, with one of these groups instead producing other sesquiterpene alcohols, whereas members of the remaining group do not produce any detectable terpenoid metabolites. Because bacterial terpene synthases typically show no significant overall sequence similarity to any other known fungal or plant terpene synthases and usually exhibit relatively low levels of mutual sequence similarity with other bacterial synthases, simple correlation of protein sequence data with the structure of the cyclized terpene product has been precluded. We have previously described a powerful search method based on the use of hidden Markov models (HMMs) and protein families database (Pfam) search that has allowed the discovery of monoterpene synthases of bacterial origin. Using an enhanced set of HMM parameters generated using a training set of 140 previously identified bacterial terpene synthase sequences, a Pfam search of 8,759,463 predicted bacterial proteins from public databases and in-house draft genome data has now revealed 262 presumptive terpene synthases. The biochemical function of a considerable number of these presumptive terpene synthase genes could be determined by expression in a specially engineered heterologous Streptomyces host and spectroscopic identification of the resulting terpene products. In addition to a wide variety of terpenes that had been previously reported from fungal or plant sources, we have isolated and determined the complete structures of 13 previously unidentified cyclic sesquiterpenes and diterpenes. PMID:25535391

  16. 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)

  17. The effect of radiation on bioluminescent bacteria: possible use of luminescent bacteria as a biological dosemeter

    International Nuclear Information System (INIS)

    The purpose of the study was to investigate the response of the bioluminescent Photobacterium phosphoreum to radiation, and the possible use of the bacteria as a biological radiation dosemeter, i.e. a water-equivalent biological system that will compare beams not merely on the basis of absorbed dose, but also have intrinsic RBE values for different radiation beams. Samples were irradiated by a 12 MeV electron beam at a dose rate of 3.0 Gy min-1, by 60Co gamma rays at 2.85 Gy min-1, and by 100 kVsub(p) x-rays at a dose rate of 2.13 Gy min-1. To study dose-rate dependence, the survival fraction was obtained for a 12 MeV electron beam at 0.50 and 12 Gy min-1 for 20.0 Gy. The survival fraction proved to be independent of dose rate in this range. The results presented in this work indicate that by using bioluminescent bacteria, RBE measurements can be markedly simplified and the results interpreted unequivocally. (U.K.)

  18. Physical mechanisms for chemotactic pattern formation by bacteria.

    OpenAIRE

    Brenner, M. P.; Levitov, L. S.; Budrene, E. O.

    1998-01-01

    This paper formulates a theory for chemotactic pattern formation by the bacteria Escherichia coli in the presence of excreted attractant. In a chemotactically neutral background, through chemoattractant signaling, the bacteria organize into swarm rings and aggregates. The analysis invokes only those physical processes that are both justifiable by known biochemistry and necessary and sufficient for swarm ring migration and aggregate formation. Swarm rings migrate in the absence of an external ...

  19. PREVALENCE OF GRAM POSITIVE BACTERIA IN IRAQI BUFFALOES DAIRY PRODUCTS

    OpenAIRE

    Zainab Oun Ali Al-Zainy; Kefah Oda Salman Al-Jeburii

    2014-01-01

    Fifty two (52) random samples of buffalo dairy products included (28) cream samples and (24) soft cheese samples ,collected from Baghdad city markets to be examined microbiologically to demonstrate the types and percentage of gram positive bacteria in these two important product that produced in farmers houses . Results revealed that the cheese samples were contaminated with Gposative bacteria (68%) and G-negative (32%). Percentage of contamination of cream samples with Gposative ...

  20. Compatible solutes in lactic acid bacteria subjected to water stress.

    OpenAIRE

    Kets, E.P.W.

    1997-01-01

    The goal of the research project described in this thesis was to investigate the protective effect of compatible solutes on tactic acid bacteria subjected to drying. Dried preparations of lactic acid bacteria are applied as starter cultures in feed and food industries. Dried starter cultures compare favourable to frozen cultures because of lower transport and storage costs. During desiccation by drying a considerable inactivation occurs resulting in low survival and subsequently, reduced resi...

  1. A REVIEW ON COMMONLY USED BIOCHEMICAL TEST FOR BACTERIA

    Directory of Open Access Journals (Sweden)

    Hemraj Vashist

    2013-05-01

    Full Text Available Bacteria are meant to be omnipresent and are mostly involved in lots of human microbial infections. Such bacterial infections can be identified by the different properties of this microorganism.  Bacteria are bearing several inherent properties. by using these properties we can differentiate, can check there presence and absence, can check their gram negative and gram positive nature and many more. The present review is therefore focused to combine different biochemical test in one article.

  2. Triclosan- resistant bacteria isolated from feedlot and residential soils

    OpenAIRE

    WELSCH, TANNER T.; Gillock, Eric T.

    2011-01-01

    Triclosan is an antimicrobial agent that is currently incorporated into hundreds of consumer and medical products. It can be either a bacteriostatic or bactericidal agent, depending on its formulation. It has activity against Gram-positive and Gram-negative bacteria, as well as some viruses and protists. The purpose of this study was to determine whether triclosan-resistant bacteria could be isolated from the soil. Soils from cattle feedlots and residential lawns were collected and assayed fo...

  3. The impact of lactic acid bacteria on sourdough fermentation

    OpenAIRE

    Savi? Dragiša S.; Jokovi? Nataša

    2005-01-01

    The baking of sourdough breads represents one of the oldest biotechnological processes. Despite traditionality, sourdough bread has great potential because of its benefits. Sourdough is a mixture of flour and water that is dominated by a complex microflora composed of yeasts and lactic acid bacteria that are crucial in the preparation of bread dough. Lactic acid bacteria cause acidification by producing lactic acid that increases the shelf life of bread by preventing the growth of undesirable...

  4. Selection of lactic acid bacteria able to ferment inulin hydrolysates

    OpenAIRE

    Baston, Octavian; Constantin, Oana Emilia

    2012-01-01

    Eight homofermentative lactic acid bacteria isolates were tested for lactic acid production using chicory and Jerusalem artichoke hydrolysate as substrate. The pH, lactic acid yield and productivity were used to select the best homolactic bacteria for lactic acid production. The selected strains produced lactic acid at maximum yield after 24 hours of fermentation and the productivity was greater at 24 hours of fermentation. From all studied strains, Lb1 and Lb2 showed the best results regardi...

  5. Presence of Multidrug Resistant Enteric Bacteria in Dairy Farm Topsoil

    OpenAIRE

    Burgos, J. M.; Ellington, B. A.; Varela, M. F.

    2005-01-01

    In addition to human and veterinary medicine, antibiotics are extensively used in agricultural settings, such as for treatment of infections, growth enhancement and prophylaxis in food animals, leading to selection of drug and multidrug resistant bacteria. In order to help circumvent the problem of bacterial antibiotic resistance, it is first necessary to understand the scope of the problem. However, is it not fully understood how widespread antibiotic resistant bacteria are in agricultural s...

  6. Oral Bacteria as Potential Probiotics for the Pharyngeal Mucosa?

    OpenAIRE

    Guglielmetti, Simone; TAVERNITI, VALENTINA; Minuzzo, Mario; Arioli, Stefania; Stuknyte, Milda; Karp, Matti; Mora, Diego

    2010-01-01

    The research described here was aimed at the selection of oral bacteria that displayed properties compatible with their potential use as probiotics for the pharyngeal mucosa. We included in the study 56 bacteria newly isolated from the pharynges of healthy donors, which were identified at the intraspecies level and characterized in vitro for their probiotic potential. The experiments led us to select two potential probiotic bacterial strains (Streptococcus salivarius RS1 and ST3) and to compa...

  7. Theory of periodic swarming of bacteria: application to Proteus mirabilis

    OpenAIRE

    Czirok, Andras; Matsushita, Mitsugu; Vicsek, Tamas

    2000-01-01

    The periodic swarming of bacteria is one of the simplest examples for pattern formation produced by the self-organized collective behavior of a large number of organisms. In the spectacular colonies of Proteus mirabilis (the most common species exhibiting this type of growth) a series of concentric rings are developed as the bacteria multiply and swarm following a scenario periodically repeating itself. We have developed a theoretical description for this process in order to...

  8. Colonization of congenitally immunodeficient mice with probiotic bacteria.

    OpenAIRE

    Wagner, R. D.; Warner, T.; Roberts, L.; Farmer, J.; Balish, E.

    1997-01-01

    We assessed the capacity of four probiotic bacteria (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei GG, and Bifidobacterium animalis) to colonize, infect, stimulate immune responses in, and affect the growth and survival of congenitally immunodeficient gnotobiotic beige-athymic (bg/bg-nu/nu) and beige-euthymic (bg/bg-nu/+) mice. The bacteria colonized and persisted, in pure culture, in the alimentary tracts of both mouse strains for the entire study period (12 weeks). A...

  9. Humic Acid Reduction by Propionibacterium freudenreichii and Other Fermenting Bacteria

    OpenAIRE

    Benz, Marcus; Bernhard SCHINK; Brune, Andreas

    1998-01-01

    Iron-reducing bacteria have been reported to reduce humic acids and low-molecular-weight quinones with electrons from acetate or hydrogen oxidation. Due to the rapid chemical reaction of amorphous ferric iron with the reduced reaction products, humic acids and low-molecular-weight redox mediators may play an important role in biological iron reduction. Since many anaerobic bacteria that are not able to reduce amorphous ferric iron directly are known to transfer electrons to other external acc...

  10. Comparative biocidal efficacy vs. sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    A number of antimicrobial compounds commonly used in cooling water, paper making, and oilfield systems were evaluated for their ability to control sessile and planktonic sulfate-reducing bacteria (SRB). While all the biocides tested are known to be effective against common planktonic, general aerobic bacteria, most were unable to control either planktonic or sessile SRB. In addition, low levels of sulfide, an SRB by-product, were found to have some effect on biocide efficacy

  11. Adhesion-related interactions of Actinomyces and Streptococcus biofilm bacteria

    OpenAIRE

    Drobni, Mirva

    2006-01-01

    Adhesion of bacteria is a key event in biofilm formation and is mediated by bacterial adhesins recognising host or bacterial partner receptors. In oral biofilm formation, primary Actinomyces and Streptococcus colonizers adhere to salivary pellicle proteins such as proline-rich proteins (PRPs) as well as to mucosal surfaces. Subsequently, Actinomyces and Streptococcus strains and other bacteria, such as Veillonella, Fusobacterium and Porphyromonas, adhere to each other. The nature of this comm...

  12. Halotolerant bacteria in the efflorescences of a deteriorated church

    OpenAIRE

    Laiz Trobajo, L.; Sa?iz-jime?nez, Cesa?reo; Cardell, C.; Rodri?guez-gordillo, J.

    2002-01-01

    [ES]: Se ha determinado la composición de las eflorescencias de la iglesia de San Jerónimo, en Granada, España, y relacionado con la presencia de comunidades específicas de bacterias. Existe una conexión entre el tipo de sales y las comunidades bacterianas; así, la epsomita, la sal más abundante en el templo, origina la selección de comunidades capaces de crecer a concentraciones de hasta,15% de esta sal. Sin embargo, las bacterias que basan su halotolerancia en la halita ...

  13. Electron transfer in syntrophic communities of anaerobic bacteria and archaea

    OpenAIRE

    Stams, A. J. M.; Plugge, C. M.

    2009-01-01

    Interspecies electron transfer is a key process in methanogenic and sulphate-reducing environments. Bacteria and archaea that live in syntrophic communities take advantage of the metabolic abilities of their syntrophic partner to overcome energy barriers and break down compounds that they cannot digest by themselves. Here, we review the transfer of hydrogen and formate between bacteria and archaea that helps to sustain growth in syntrophic methanogenic communities. We also describe the proces...

  14. Bacteria and cancer: cause, coincidence or cure? A review

    OpenAIRE

    Dl, Mager

    2006-01-01

    Abstract Research has found that certain bacteria are associated with human cancers. Their role, however, is still unclear. Convincing evidence links some species to carcinogenesis while others appear promising in the diagnosis, prevention or treatment of cancers. The complex relationship between bacteria and humans is demonstrated by Helicobacter pylori and Salmonella typhi infections. Research has shown that H. pylori can cause gastric cancer or MALT lymphoma in some individuals. In contras...

  15. Inhibition of bacteria contaminating alcoholic fermentations by killer yeasts

    OpenAIRE

    Maria Cristina Meneghin; Vanda Renata Reis; Sandra Regina Ceccato-Antonini

    2010-01-01

    The aim of this work was to study the in vitro antibacterial activity possessed by killer yeast strains against bacteria contaminating alcoholic fermentation (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides), in cell X cell and cell X crude toxin preparations. The bacteria were not inhibited by any S. cerevisiae killer strains (5 out of 11). The inhibition caused by two crude toxin preparations (Trichosporon figueirae and Candida sp) against L...

  16. Antimicrobial Potential Of Azadirachta Indica Against Pathogenic Bacteria And Fungi

    OpenAIRE

    Mohammad Asif

    2012-01-01

    Drugs from natural sources are used for treating various diseases since the ancient times. From the literature it is clear that various type of pharmacological and biological activities are associated with Azadirachta indica. Theleave oil of A. indica is known to have good antimicrobial potential. The oil of A. indica leaves, was tested against the different infectious microorganisms [Gram positive bacteria and Gram-negative bacteria], such as bacterial strains; S. aureus, E. coli, B. cerus, ...

  17. Structured habitats and the evolution of anticompetitor toxins in bacteria.

    OpenAIRE

    Chao, L.; Levin, B. R.

    1981-01-01

    We demonstrate that in liquid cultures, defined in this study as a mass habitat, the outcome of competition between Escherichia coli that produce an antibacterial toxin (colicin) and sensitive E. coli is frequency dependent; the colicinogenic bacteria are at an advantage only when fairly common (frequencies in excess of 2 X 10(-2)). However, we also show that in a soft agar matrix, a structured habitat, the colicinogenic bacteria have an advantage even when initially rare (frequencies as low ...

  18. Bacteria under ice: Some don't like it hot

    Science.gov (United States)

    Richard Monastersky

    This article written by Richard Monastersky of Science News Online describes the work of Martin Sharp of the University of Alberta and colleagues from the United Kingdom. This group began searching for cold-loving bacteria after their discovery of unexplainable chemical reactions beneath the ice of a Swiss glacier. Included in this online article are links to further readings by Monastersky which are related to sub-surface "deep dwelling" bacteria, and other Science News Online articles

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

    OpenAIRE

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

    2012-01-01

    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 poten...

  20. Massive comparative genomic analysis reveals convergent evolution of specialized bacteria

    Directory of Open Access Journals (Sweden)

    Raoult Didier

    2009-04-01

    Full Text Available Abstract Background Genome size and gene content in bacteria are associated with their lifestyles. Obligate intracellular bacteria (i.e., mutualists and parasites have small genomes that derived from larger free-living bacterial ancestors; however, the different steps of bacterial specialization from free-living to intracellular lifestyle have not been studied comprehensively. The growing number of available sequenced genomes makes it possible to perform a statistical comparative analysis of 317 genomes from bacteria with different lifestyles. Results Compared to free-living bacteria, host-dependent bacteria exhibit fewer rRNA genes, more split rRNA operons and fewer transcriptional regulators, linked to slower growth rates. We found a function-dependent and non-random loss of the same 100 orthologous genes in all obligate intracellular bacteria. Thus, we showed that obligate intracellular bacteria from different phyla are converging according to their lifestyle. Their specialization is an irreversible phenomenon characterized by translation modification and massive gene loss, including the loss of transcriptional regulators. Although both mutualists and parasites converge by genome reduction, these obligate intracellular bacteria have lost distinct sets of genes in the context of their specific host associations: mutualists have significantly more genes that enable nutrient provisioning whereas parasites have genes that encode Types II, IV, and VI secretion pathways. Conclusion Our findings suggest that gene loss, rather than acquisition of virulence factors, has been a driving force in the adaptation of parasites to eukaryotic cells. This comparative genomic analysis helps to explore the strategies by which obligate intracellular genomes specialize to particular host-associations and contributes to advance our knowledge about the mechanisms of bacterial evolution. Reviewers This article was reviewed by Eugene V. Koonin, Nicolas Galtier, and Jeremy Selengut.

  1. Biodegradation of Asphalt Cement-20 by Aerobic Bacteria

    OpenAIRE

    Pendrys, John P.

    1989-01-01

    Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-...

  2. Viability of bacteria in dental calculus – A microbiological study

    OpenAIRE

    Moolya Nikesh; Thakur Srinath; Ravindra S; Setty Swati; Kulkarni Raghavendra; Hallikeri Kaveri

    2010-01-01

    Aim: The aim of this study was (1) To investigate the viability of bacteria within supragingival and subgingival calculus, (2) To examine motility of bacteria, and (3) To identify bacterial morphotypes in calculus. Materials and Methods: Supra and subgingival calculus were harvested from 30 subjects having clinical evidence of chronic inflammatory periodontal disease and were divided into two groups . Samples from both groups were immediately transported to the Department of Microbiology for ...

  3. High Motility Reduces Grazing Mortality of Planktonic Bacteria

    OpenAIRE

    Matz, Carsten; Ju?rgens, Klaus

    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 that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 ?m s?1 as a result of handling problems with highly motile cells. Com...

  4. Engineering Bacteria To Recognize And Follow Small Molecules

    OpenAIRE

    Mishler, Dennis M.; Topp, Shana; Reynoso, Colleen M. K.; Gallivan, Justin P.

    2010-01-01

    The ability to recognize and react to specific environmental cues allows bacteria to localize to environments favorable to their survival and growth. Synthetic biologists have begun to exploit the chemosensory pathways that control cell motility to reprogram how bacteria move in response to novel signals. Reprogramming is often accomplished by designing novel protein or RNA parts that respond to specific small molecules not normally recognized by the natural chemosensory pathways. Additionall...

  5. Halophilic Bacteria as a Source of Novel Hydrolytic Enzymes

    OpenAIRE

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

    2013-01-01

    Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. The halotolerance of many enzymes derived from halophilic bacteria can be exploited wherever enzymatic transformations are required to function under physical and chemical conditions, such as in the presence of organic solvents and extremes in temperature and salt content. In recent years, different screening programs have been performed in saline habitats in order to isolate and characte...

  6. ANTAGONISTIC BACTERIA AGAINST SCHIZOPHYLLUM COMMUNE FR. IN PENINSULAR MALAYSIA

    OpenAIRE

    ANTARJO DIKIN; KAMARUZAMAN SIJAM; JUGAH KADIR; IDRIS ABU SEMAN

    2006-01-01

    Schizophyllum commune Fr., is one of the important fungi, causes brown germ and seed rot of oil palm. Biodiversity of antagonistic bacteria from oil palm plantations in Peninsular Malaysia is expected to support in development of biopesticide. Isolation with liquid assay and screening antagonistic bacteria using dual culture assay were carried out in the bioexploration. A total of 265 bacterial isolates from plant parts of oil palm screened 52 antagonistic bacterial isolates against 5. commu...

  7. Knowledge discovery for the treatment of bacteria affecting the liver

    OpenAIRE

    YILDIRIM, P?nar; ÇEKEN, Ka?an; SAKA, Osman

    2011-01-01

    Biomedical information is buried in millions of published articles, and so it is necessary to use text mining techniques to skim published articles for relevant information. In this study, we used biomedical text mining techniques to introduce a liver bacterial infection knowledge-acquisition information system. Materials and methods: Bacteria names were selected from Medline MeSH data and it was searched to identify the most frequent bacteria associated with the liver using a text mining sy...

  8. Perlite as a carrier of phosphate-accumulating bacteria

    International Nuclear Information System (INIS)

    The phosphate (P)-accumulating bacteria are important for biological P removal from wastewater. Currently, attention is being drawn to the immobilisation of desired bacteria on different carriers in order to achieve a better efficiency of the wastewater treatment. In this study, two size fractions (0.1-1 and 0.1-2 mm) of different forms of expanded perlite (original, autoclaved and magnesium-exchanged) were investigates as possible carriers of P accumulating bacterium. (Author)

  9. Screening of polyhydroxyalkanoates producing bacteria isolated from marine ecosystems

    OpenAIRE

    Baptista, Silvia Almeida

    2013-01-01

    Polyhydroxyalkanoates (PHAs) are biodegradable polyesters and environmentally friendly thermoplastics, which are accumulated as carbon and energy storage materials in various bacteria in limited growth conditions with excess carbon sources. In this study, bacteria were isolated from samples taken from various marine ecosystems in the Archipelago of Madeira in the Atlantic Ocean, and screened for their ability to accumulate polyhydroxyalkanoates. These samples were taken from the seabed at ...

  10. Washing with contaminated bar soap is unlikely to transfer bacteria.

    OpenAIRE

    Heinze, J. E.; Yackovich, F.

    1988-01-01

    Recent reports of the isolation of microorganisms from used soap bars have raised the concern that bacteria may be transferred from contaminated soap bars during handwashing. Since only one study addressing this question has been published, we developed an additional procedure to test this concern. In our new method prewashed and softened commercial deodorant soap bars (0.8% triclocarban) not active against Gram-negative bacteria were inoculated with Escherichia coli and Pseudomonas aeruginos...

  11. Importance of lactic acid bacteria in Asian fermented foods

    OpenAIRE

    Rhee, Sook Jong; Lee, Jang-Eun; Lee, Cherl-Ho

    2011-01-01

    Lactic acid bacteria play important roles in various fermented foods in Asia. Besides being the main component in kimchi and other fermented foods, they are used to preserve edible food materials through fermentation of other raw-materials such as rice wine/beer, rice cakes, and fish by producing organic acids to control putrefactive microorganisms and pathogens. These bacteria also provide a selective environment favoring fermentative microorganisms and produce desirable flavors in various f...

  12. Removal of Cholera Toxin from Aqueous Solution by Probiotic Bacteria

    OpenAIRE

    Meriluoto, Jussi A. O.; Heikkila?, Jari E.; Nybom, Sonja M. K.; Salminen, Seppo J.

    2012-01-01

    Cholera remains a serious health problem, especially in developing countries where basic hygiene standards are not met. The symptoms of cholera are caused by cholera toxin, an enterotoxin, which is produced by the bacterium Vibrio cholerae. We have recently shown that human probiotic bacteria are capable of removing cyanobacterial toxins from aqueous solutions. In the present study we investigate the ability of the human probiotic bacteria, Lactobacillus rhamnos...

  13. Las grandes bacterias del Sulfureto de Humboldt / The big bacteria in the Humboldt Sulfuretum

    Scientific Electronic Library Online (English)

    Víctor Ariel, Gallardo; Carola, Espinoza; Alexis, Fonseca; Selim, Musleh.

    Full Text Available Durante el primer estudio nacional de la zona de mínimo oxígeno (ZMO) y del macrobentos animal costa afuera del norte de Chile (1962), se descubrió una comunidad bentónica compuesta de bacterias filamentosas multicelulares gigantes en los sedimentos fuertemente reducidos entre 50 y182 m. La masiva a [...] bundancia de filamentos bacterianos visibles a simple vista y el extremadamente escaso macrobentos animal, fueron rasgos inesperados. Más recientemente (2004) un nuevo ensamble de bacterias filamentosas multicelulares más pequeñas fue descubierto distribuido en los sedimentos más reducidos sub-superficiales del tapiz bacteriano. Hoy reconocemos que este ecosistema dominado por procariotas constituye un rasgo mayor y distinto al nivel mundial el que aquí denominamos "Sulfureto de Humboldt" (SH) por su distribución entre Perú central y Chile central. Durante un largo periodo de una intensa investigación que surge después de 1977, con fuerte contribución internacional, se ha acumulado un gran cuerpo de información sobre el primer ensamble y su ambiente, fundamental para la comprensión del funcionamiento del Gran Ecosistema Marino de Humboldt, en tanto que la investigación sobre el segundo ensamble recién comienza. El presente trabajo es un esfuerzo para reunir la mayor parte de la literatura pertinente con la intención de estimular a los científicos locales a enfrentar el necesario y urgente gran esfuerzo de investigación en las diversas líneas que la biota y el ambiente del Sulfureto de Humboldt ofrecen. Abstract in english During the first national study of the oxygen minimum zone (OMZ) and the animal macrobenthos off northern Chile (1962), a benthic community mainly composed of giant filamentous multicellular bacteria was discovered in the highly reduced shelf bottoms between 50-182 m depth. Totally unexpected were t [...] he great abundance of massive and visible filamentous bacteria and the pronounced scarcity of macrobenthic animals. More recently (2004) a new assemblage of smaller filamentous multicellular bacteria was again discovered interspersed within the more reduced subsurface sediment of the same bacterial mat. Today we recognize that this prokaryote-dominated ecosystem constitutes a major distinct benthic marine feature and thus it is here named "Humboldt Sulfuretum" (HS) for his distribution under the OMZ between central Peru and central Chile. During a period of intense scientific research which took off after 1977, strongly based on international collaboration, a large body of information fundamental to the understanding of the Humboldt Current Large Marine Ecosystem has accumulated on the first assemblage and its environment while the research on the second assemblage is just beginning. The present work is an effort to put together most of the pertinent literature with the intention of stimulating local researchers to face the much urgent, major scientific effort along the many lines offered by the biota and the environment of the Humboldt Sulfuretum.

  14. Separation of motile bacteria using drift velocity in a microchannel.

    Science.gov (United States)

    Ishikawa, Takuji; Shioiri, Tatsuya; Numayama-Tsuruta, Keiko; Ueno, Hironori; Imai, Yohsuke; Yamaguchi, Takami

    2014-03-01

    Separation of certain bacteria from liquids is important in the food, water quality management, bioengineering, and pharmaceutical industries. In this study, we developed a microfluidic device for the hydrodynamic separation of motile bacteria (Escherichia coli) using drift velocity. We first investigated drift tendencies of bacteria and found that cells tended to move in a spanwise direction with similar velocities regardless of the flow rate. When the drift distance was small compared to the wetted perimeter of the cross section, the cells were not separated efficiently. We then investigated the drift phenomenon in more detail using a numerical simulation. Interestingly, the drift phenomenon was observed even without a wall boundary, indicating that drift was caused mainly by the interaction of moving cells with the background shear flow. Finally, we developed a microfluidic device to separate motile bacteria from tracer particles or less motile cells. By decreasing the channel height, the device could successfully separate motile bacteria from other particles or cells with a separation efficiency of about 40%. Connecting microchannels in a series was also found to be effective, which achieved the separation efficiency of about 60%. The knowledge obtained in this study will facilitate the development of other microfluidics devices for use with bacteria. PMID:24448484

  15. Bacteria responsive antibacterial surfaces for indwelling device infections.

    Science.gov (United States)

    Traba, Christian; Liang, Jun F

    2015-01-28

    Indwelling device infections now represent life-threatening circumstances as a result of the biofilms' tolerance to antibiotic treatments. Current antibiotic impregnation approaches through sustained antibiotic release have some unsolved problems which include short life-span, narrowed antibacterial spectrum, ineffectiveness towards resistant mutants, and the potential to hasten the antibiotic resistance process. In this study, bacteria responsive anti-biofilm surfaces were developed using bioactive peptides with proved activity to antibiotic resistant bacteria and biofilms. Resulting surfaces were stable under physiological conditions and in the presence of high concentrations of salts (0.5M NaCl) and biomacromolcules (1.0% DNA and 2.0% alginate), and thus showed good biocompatibility to various tissue cells. However, lytic peptide immobilized surfaces could sense bacteria adhesion and kill attached bacteria effectively and specifically, so biofilms were unable to develop on the lytic peptide immobilized surfaces. Bacteria responsive catheters remained biofilm free for up to a week. Therefore, the bacteria responsive antibacterial surfaces developed in this study represent new opportunities for indwelling device infections. PMID:25481445

  16. The impact of lactic acid bacteria on sourdough fermentation

    Directory of Open Access Journals (Sweden)

    Savi? Dragiša S.

    2005-01-01

    Full Text Available The baking of sourdough breads represents one of the oldest biotechnological processes. Despite traditionality, sourdough bread has great potential because of its benefits. Sourdough is a mixture of flour and water that is dominated by a complex microflora composed of yeasts and lactic acid bacteria that are crucial in the preparation of bread dough. Lactic acid bacteria cause acidification by producing lactic acid that increases the shelf life of bread by preventing the growth of undesirable microorganisms and affects the nutritional value of bread by increasing the availability of minerals. In addition to these advantages, the use of sourdough fermentation also improves dough machinability, breadcrumb structure and the characteristic flavour of bread. Lactic acid bacteria in sourdough fermentation are well known representing both homofermentative and heterofermentative bacteria. They may originate from selected natural contaminants in the flour or from a starter culture containing one or more known species of lactic acid bacteria. Sourdough can be cultivated in bakeries or obtained from commercial suppliers. However, many bakeries in Europe still use spontaneously fermented sourdoughs, which have been kept metabolically active for decades by the addition of flour and water at regular intervals. The impact of lactic acid bacteria on sourdough fermentation and their influence on dough and bread quality was discussed on the basis of research and literature data.

  17. The Pho regulon: a huge regulatory network in bacteria

    Science.gov (United States)

    Santos-Beneit, Fernando

    2015-01-01

    One of the most important achievements of bacteria is its capability to adapt to the changing conditions of the environment. The competition for nutrients with other microorganisms, especially in the soil, where nutritional conditions are more variable, has led bacteria to evolve a plethora of mechanisms to rapidly fine-tune the requirements of the cell. One of the essential nutrients that are normally found in low concentrations in nature is inorganic phosphate (Pi). Bacteria, as well as other organisms, have developed several systems to cope for the scarcity of this nutrient. To date, the unique mechanism responding to Pi starvation known in detail is the Pho regulon, which is normally controlled by a two component system and constitutes one of the most sensible and efficient regulatory mechanisms in bacteria. Many new members of the Pho regulon have emerged in the last years in several bacteria; however, there are still many unknown questions regarding the activation and function of the whole system. This review describes the most important findings of the last three decades in relation to Pi regulation in bacteria, including: the PHO box, the Pi signaling pathway and the Pi starvation response. The role of the Pho regulon in nutritional regulation cross-talk, secondary metabolite production, and pathogenesis is discussed in detail.

  18. Effect of chitosan coating on a bacteria-based alginate microrobot.

    Science.gov (United States)

    Park, Sung Jun; Lee, Yu Kyung; Cho, Sunghoon; Uthaman, Saji; Park, In-Kyu; Min, Jung-Joon; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-04-01

    To develop an efficient bacteria-based microrobot, first, therapeutic bacteria should be encapsulated into microbeads using biodegradable and biocompatible materials; second, the releasing rate of the encapsulated bacteria for theragnostic function should be regulated; and finally, flagellated bacteria should be attached on the microbeads to ensure the motility of the microrobot. For the therapeutic bacteria encapsulation, an alginate can be a promising candidate as a biodegradable and biocompatible material. Owing to the non-regulated releasing rate of the encapsulated bacteria in alginate microbeads and the weak attachment of flagellated bacteria on the surface of alginate microbeads, however, the alginate microbeads cannot be used as effective cargo for a bacteria-based microrobot. In this paper, to enhance the stability of the bacteria encapsulation and the adhesion of flagellated bacteria in alginate microbeads, we performed a surface modification of alginate microbeads using chitosan coating. The bacteria-encapsulated alginate microbeads with 1% chitosan coating maintained their structural integrity up to 72?h, whereas the control alginate microbead group without chitosan coating showed severe degradations after 24?h. The chitosan coating in alginate microbeads shows the enhanced attachment of flagellated bacteria on the surface of alginate microbeads. The bacteria-actuated microrobot with the enhanced flagellated bacteria attachment could show approximately 4.2 times higher average velocities than the control bacteria-actuated microrobot without chitosan coating. Consequently, the surface modification using chitosan coating enhanced the structural stability and the motility of the bacteria-based alginate microrobots. PMID:25312282

  19. The effects of deuterium-depleted water on bacteria

    International Nuclear Information System (INIS)

    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 mm2 occurred; - 3. strong response when the clear area was higher than 10 mm2. 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 verresponse 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 mm2. Even if the DDW effect seems to be small it was significantly in comparison with the control case (sd = 2.78 mm2 > 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 mm2 after 24 h and on 26.95 mm2 after 48 h, being very significantly different from the control area (sd = 8.71 mm2 and sd = 10.04 mm2 > 0.01, respectively). In conclusion the DDW had a variable inhibiting effect upon bacteria. It revealed the bactericidal effect in 60% of the cases. The DDW effect appeared to be strongly correlated with the genotype. It is necessary to experimentalize the bactericidal effect on other bacteria. (authors)

  20. Crystallization and preliminary X-ray diffraction studies of two thermostable ?-galactosidases from glycoside hydrolase family 36

    Energy Technology Data Exchange (ETDEWEB)

    Foucault, M. [Institut de Biologie et Chimie des Protéines, CNRS-UCBL, UMR 5086, Laboratoire de Bio-Cristallographie IFR128 ‘BioSciences Lyon-Gerland’, 7 Passage du Vercors, 69367 Lyon CEDEX 07 (France); Watzlawick, H.; Mattes, R. [Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, D-70569 Stuttgart (Germany); Haser, R.; Gouet, P., E-mail: p.gouet@ibcp.fr [Institut de Biologie et Chimie des Protéines, CNRS-UCBL, UMR 5086, Laboratoire de Bio-Cristallographie IFR128 ‘BioSciences Lyon-Gerland’, 7 Passage du Vercors, 69367 Lyon CEDEX 07 (France)

    2006-02-01

    The ?-galactosidases AgaA, AgaB and AgaA A355E mutant from Geobacillus stearothermophilus have been overexpressed in Escherichia coli. Crystals of AgaB and AgaA A355E have been obtained by the vapour-diffusion method and synchrotron data have been collected to 2.0 and 2.8 Å resolution, respectively. ?-Galactosidases from thermophilic organisms have gained interest owing to their applications in the sugar industry. The ?-galactosidases AgaA, AgaB and AgaA A355E mutant from Geobacillus stearothermophilus have been overexpressed in Escherichia coli. Crystals of AgaB and AgaA A355E have been obtained by the vapour-diffusion method and synchrotron data have been collected to 2.0 and 2.8 Å resolution, respectively. Crystals of AgaB belong to space group I222 or I2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 87.5, b = 113.3, c = 161.6 Å. Crystals of AgaA A355E belong to space group P3{sub 1}21 or P3{sub 2}21, with unit-cell parameters a = b = 150.1, c = 233.2 Å.

  1. The effects of bacteria on the corrosion behavior of carbon steel in compacted bentonite

    International Nuclear Information System (INIS)

    As a part of evaluation of corrosion life of carbon steel overpack, the experimental studies have been performed on the effects of bacteria on the corrosion behavior of carbon steel in compacted bentonite using iron bacteria (IB) as a representative oxidizing bacteria and sulphur reducing bacteria (SRB) as a representative reducing bacteria. The results of the experimental studies showed that; The activity of SRB was low in compacted bentonite in spite of applying suitable condition for the action of bacteria such as temperature and nutritious solution. Although the corrosion behavior of carbon steel was affected by the existence of bacteria in simple solution, the corrosion rates of carbon steel in compacted bentonite were several ? m/year -10 ? m/year irrespective of coexistence of bacteria and that the corrosion behavior was not affected by the existence of bacteria. According to these results, it was concluded that the bacteria would not affect the corrosion behavior of carbon steel overpack under repository condition. (author)

  2. Epidemiology of nosocomial bacteria resistant to antimicrobials / Epidemiología de bacterias nosocomiales resistentes a los antimicrobianos

    Scientific Electronic Library Online (English)

    Cristina E., Cabrera; Romel F, Gómez; Andrés E., Zuñiga; Raúl H., Corral; Bertha, López; Mónica, Chávez.

    2011-03-01

    Full Text Available Las infecciones nosocomiales constituyen un gran desafío para la salud pública por las altas tasas de morbilidad y mortalidad que generan. Se ha considerado que el uso inapropiado o excesivo de antibióticos desencadena la aparición de cepas resistentes. Entre las bacterias de importancia clínica que [...] con mayor frecuencia causan infecciones nososcomiales, se destacan los patógenos Gram positivos multiresistentes como Staphylococcus aureus con resistencia a meticilina (SARM) y Enterococcus spp. resistentes a vancomicina (ERV). En los Gram negativos, hay resistencia sobre todo con las cepas de Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp. y Acinetobacter baumannii productoras de ?-lactamasas de espectro extendido (BLEEs, en inglés: ES?L expanded spectrum ?-lactamases). Esta revisión tiene como finalidad realizar una decripción del estado de la resistencia bacteriana a los antibióticos en los principales patógenos que causan infecciones nosocomiales en países de Europa, Estados Unidos y de Latinoamérica, destacando los estudios de epidemiología molecular a escala global e incluyendo los principales estudios epidemiológicos realizados en Colombia. La estructura genética de las cepas de Staphylococus aureus y Enterococcus spp. evidencia una característica clonal favorecida por el predominio de un número pequeño de clones con capacidad de diseminarse en forma global, debida probablemente a infecciones cruzadas. Sin embargo, la introducción de cepas SARM desde la comunidad está favoreciendo la diversidad genética, tendiendo a establecerse una estructura genética policlonal en lugares endémicos como los Estados Unidos. En las bacterias Gram negativas, se destaca una alta diversidad genética entre los aislados, sobre todo en países de Latinoamérica, indicando que la diseminación sigue una estructura genética policlonal, influida por la transferencia horizontal de plasmidos, por la excesiva exposición a antibióticos y una estancia hospitalaria prolongada. En Colombia se dispone de información sobre los patógenos nosocomiales resistentes, pero la información epidemiológica molecular aún es escasa. Abstract in english Nosocomial infections are a major challenge for public health because of the high rates of morbidity and mortality generated. It was considered that the excessive or inappropriate use of antibiotics triggers the emergence of resistant strains. Among the clinically important bacteria that most common [...] ly cause nososcomial infections, Gram positive multiresistant pathogens stand out such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp (VRE), and the Gram negative strains of Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp. and Acinetobacter baumannii producing expanded spectrum ?-lactamases (ES?L). This review describes the behavior of the main bacterial pathogens resistant to antibiotics that cause infections in Europe, United States, and Latin America, emphasizing studies of molecular epidemiology on a global scale, including the major epidemiological studies in Colombia. The genetic structure of S. aureus and Enterococcus spp strains shows a clonal characteristic favored by the predominance of a small number of clones with the capacity to spread globally, due probably to cross-infection. However, the introduction of MRSA strains from the community encourages genetic diversity, tending to establish a genetic polyclonal endemic structure in places like the United States. In Gram negative bacteria, the high genetic diversity among isolates, mainly in Latin American countries, indicates that the polyclonal spread is influenced by horizontal transfer of plasmids, by excessive exposure to antibiotics, and prolonged hospital stays. In Colombia, there is information on nosocomial resistant pathogens, but molecular epidemiological information is still scarce.

  3. Remediation of Pb-Resistant Bacteria to Pb Polluted Soil

    Directory of Open Access Journals (Sweden)

    Jing-hua Fan

    2011-03-01

    Full Text Available To show the remediation of Pb-resistant bacteria to Pb polluted soil, several indices including microbial counts, soil enzyme activity, microbial community diversity and soil Pb concentration were investigated. Two Pb-resistant bacteria were filtrated and identified by previous study as Bacillus pumilus and Pseudomonas aeruginosa (GeneBank Accession No. FJ402988 and GU017676 and inoculated to soil planted with cabbages. Soil with different Pb application rates were incubated for a period of 0, 12, 24, 36, 48 days in greenhouse. Results indicated the count of bacteria in 1000 mg/kg Pb treated soil greatly affected by inoculating Pb-resistant bacteria, which was raised about 237% and 347% compared with control. Soil urease and invertase were intensified 37.9% and 65.6% after inoculation compared with control. Phosphatase activity was inhibited by inoculation of Bacillus pumilus. Catalase activity was intensified about 64.2% in 24 days incubation but decrease in the following days. Microbial community diversity analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE also proved that the samples inoculated with Pb-resistant bacteria exhibited more bands and intensity in DGGE patterns compared with uninoculated ones. For Pb-resistant bacteria inoculated samples, the reduction of Pb concentration in rhizospheric soil was 15 mg/kg at least and 42 mg/kg at most, and Pseudomonas aeruginosa showed a better tolerance to high Pb concentration and stronger remediation ability. It was concluded that remediation of Pb polluted soil can be promoted by the two Pb-resistant bacteria.

  4. Selective recruitment of bacteria during embryogenesis of an earthworm.

    Science.gov (United States)

    Davidson, Seana K; Stahl, David A

    2008-05-01

    Earthworms of the family Lumbricidae harbor specific and stable populations of Acidovorax-like bacteria within their excretory organs, the nephridia. The symbionts of Eisenia foetida are deposited into the egg capsules during mating and the nephridia of the juveniles are colonized before they hatch. The timing and mechanisms governing bacterial recruitment and colonization are unknown for the earthworm-Acidovorax association. This study examined the process of colonization of the symbiotic organ during development of the embryos within the egg capsules. Bacteria associated with the developing embryos were visualized using in situ hybridization to bacterial cells and laser scanning confocal microscopy. Bacterial cells were associated with earthworm embryos during the earliest stages of development-the ova through to hatching. Three-dimensional examination of stages of development revealed an embryonic duct that recruits the Acidovorax-like symbiont cells. As each segment matures, Acidovorax-like symbiotic bacteria are recruited into this duct, excluding most other bacterial types, and remain there for a period of days prior to migration into the nephridium. After colonization of the nephridial ampulla, the canal remains bacteria-free. In addition to the known Acidovorax-like bacteria, multiple types of bacteria interact with the embryos externally and internally during the full course of development, and ultimately fill the gut lumen near the end of development prior to hatching. Colonization of the correct tissues by specific bacteria during differentiation and maturation of the organs must involve selective host defenses and signaling between the two partners to prevent over growth of nascent tissues. PMID:18273064

  5. Production of folate by bacteria isolated from oat bran.

    Science.gov (United States)

    Kariluoto, Susanna; Edelmann, Minnamari; Herranen, Mirkka; Lampi, Anna-Maija; Shmelev, Anton; Salovaara, Hannu; Korhola, Matti; Piironen, Vieno

    2010-09-30

    Twenty bacteria isolated from three commercial oat bran products were tested for their folate production capability. The bacteria as well as some reference organisms were grown until early stationary phase on a rich medium (YPD), and the amount of total folate in the separated cell mass and the culture medium (supernatant) was determined by microbiological assay. Folate vitamer distribution was determined for eight bacteria including one isolated from rye flakes. For seven bacteria the effect of temperature and pH on folate production was studied in more detail. Relatively large amount of folate was both produced in the cell biomass (up to 20.8microg/g) and released to the culture medium (up to 0.38microg/g) by studied bacteria. The best producers were characterized as Bacillus subtilis ON4, Chryseobacterium sp. NR7, Janthinobacterium sp. RB4, Pantoea agglomerans ON2, and Pseudomonas sp ON8. The level of folate released in culture medium was the highest for B. subtilis ON5, Chryseobacterium sp. NR7, Curtobacterium sp. ON7, Enterococcus durans ON9, Janthinobacterium sp. RB4, Paenibacillus sp. ON10, Propionibacterium sp. RB9, and Staphylococcus kloosii RB7. Marked differences in the distribution of folate vitamers among the bacterial strains were revealed by the HPLC analysis. The main vitamers were tetrahydrofolate, 5,10-methenyltetrahydrofolate, 5-methyltetrahydrofolate, and 5-formyltetrahydrofolate. Increase in the folate content during bacterial growth was accompanied by proportional increase in the 5-methyltetrahydrofolate content and decrease of 5-formyltetrahydrofolate. 10-Formylfolic acid dominated in the culture media of four bacteria, and Janthinobacterium sp. RB4 was also found to excrete 5-methyltetrahydrofolate. Intracellular folate content was higher when the bacteria were grown at 28 degrees C than at 18 degrees C or 37 degrees C and also higher at pH 7 than at pH 5.5. PMID:20708290

  6. Isolation and Identification of Epiphytic Lactic Acid Bacteria from Guinea Grass (Panicum maximum)

    OpenAIRE

    Pasebani, M.; Yaakub, H.; Sijam, K.; Alimon, A. R.

    2010-01-01

    Problem statement: Bacteria can perform a variety of beneficial functions, for example many lactic acid bacteria are responsible for fermentation of silage in the process of forage conservation. In the making of silage, epiphytic lactic acid bacteria are usually insufficient in numbers to promote efficient lactate fermentation. This study was conducted to identify the predominant indigenous bacteria, with emphasis on lactic acid bacteria, from Guinea grass (Panicum maximum). Approach: Two dif...

  7. Distribution of the Bacteria Involved in the Nitrogen and Sulfur Cycle in ?zmir Bay

    OpenAIRE

    GÜNGÖR, Fatma

    1999-01-01

    Qualitative seasonal distributions of sulfate-reducing bacteria, colorless sulfur bacteria, nitrifying and denitrifying bacteria in the water and sediment samples in the inner part of ?zmir Bay were investigated in relation to certain physico-chemical parameters (pH, oxygen, hydrogen sulfide, nitrate, nitrite, ammonium). Denitrifying bacteria and sulfate-reducing bacteria were present in the sediment and even in the aerobic water samples. Hydrogen sulfide was found almost in all water sample...

  8. Isolation, Characterization, and Genetic Diversity of Ice Nucleation Active Bacteria on Various Plants

    OpenAIRE

    DIANA ELIZABETH WATURANGI; AMELIA TJHEN

    2009-01-01

    Ice nucleation active (INA) bacteria is a group of bacteria with the ability to catalyze the ice formation at temperature above -10 oC and causing frost injury in plants. Since, most of the literature on INA bacteria were from subtropical area, studies of INA bacteria from tropical area are needed. We sampled eight fruits and 36 leaves of 21 plant species, and then identified through biochemical and genetic analysis. INA bacteria were characterized for INA protein classification, pH stability...

  9. Protozoan Response to the Addition of Bacterial Predators and Other Bacteria to Soil †

    OpenAIRE

    Casida, L. E.

    1989-01-01

    Representatives of several categories of bacteria were added to soil to determine which of them might elicit responses from the soil protozoa. The various categories were nonobligate bacterial predators of bacteria, prey bacteria for these predators, indigenous bacteria that are normally present in high numbers in soil, and non-native bacteria that often find their way in large numbers into soil. The soil was incubated and the responses of the indigenous protozoa were determined by most-proba...

  10. Low field orientation magnetic separation methods for magnetotactic bacteria

    International Nuclear Information System (INIS)

    Microbial biomineralisation of iron often results in a biomass that is magnetic and can be separated from water systems by the application of a magnetic field. Magnetotactic bacteria form magnetic membrane bound crystals within their structure, generally of magnetite. In nature, this enables magnetotactic bacteria to orientate themselves with respect to the local geomagnetic field. The bacteria then migrate with flagellar driven motion towards their preferred environment. This property has been harnessed to produce a process in which metal loaded magnetotactic bacteria can be recovered from a waste stream. This process is known as orientation magnetic separation. Several methods exist which permit the unique magnetic properties of individual magnetotactic bacteria to be studied, such as U-turn analysis, transmission electron microscopy and single wire cell studies. In this work an extension of U-turn analysis was developed. The bacteria were rendered non-motile by the addition of specific metal ions and the resulting 'flip time' which occurs during a field reversal enabled the magnetic moment of individual bacteria to be determined. This method proved to be much faster and more accurate than previous methods. For a successful process to be developed, large scale culturing of magnetotactic bacteria is required Experiments showed that culture vessel geometry was an important factor for high-density growth. Despite intensive studies reproducible culturing at volumes exceies reproducible culturing at volumes exceeding one litre was not achieved. This work showed that numerous metal ions rendered magnetotactic bacteria non-motile at concentrations below 10 ppm. Sequential adaptation raised typical levels to in excess of 100 ppm for a number of ions. such as zinc and tin. However, specific ions. such as copper or nickel, remained motility inhibiting at lower concentrations. To achieve separation using orientation magnetic separation, motile, field susceptible MTB are required. Despite successful adaptation, the range of motility inhibiting ions is such that MTB cannot be envisaged for general wastewater applications. Radionucleide studies were undertaken targeting a niche application where this metal ion restriction would not apply. Liquid scintillation and ?-ray counting measurements indicated that magnetotactic bacteria accumulate high levels of both plutonium and mercury. A number of both static and flow recovery separators for magnetotactic bacteria were developed. Statistical models predicting the behaviour of these separators were compared to measured results. These comparisons highlighted the problems of 'wash off' of accumulated bacteria in separators where flow was present. The most successful of the flow recovery designs - the channel separator - was then tested using a simulated effluent that contained plutonium. The results confirmed both previous radioisotope uptake studies and separator test results. The channel separator design was enhanced by the introduction of wire arrays into the separation chamber. Orientation magnetic separation in these hybrid-type separators was used to accumulate the biomass and the magnetic gradients generated by the wire arrays to retain the bacteria on the separator walls. These separators achieved increases in efficiency of up to 300% compared with the channel separator. In summary, this thesis describes a successful separation process for the recovery of motile MTB. However, to apply this separator approach to the suggested radioisotope application would require successful large scale culturing. (author)

  11. ATP Synthesis in the Extremely Halophilic Bacteria

    Science.gov (United States)

    Hochstein, Lawrence I.; Morrison, David (Technical Monitor)

    1994-01-01

    The proton-translocating ATPases are multimeric enzymes that carry out a multitude of essential functions. Their origin and evolution represent a seminal event in the early evolution of life. Amino acid sequences of the two largest subunits from archaeal ATPases (A-ATPases), vacuolar ATPases (V-ATPases), and FOF1-ATP syntheses (FATPases) suggest these ATPases evolved from an ancestral vacuolar-like ATP syntheses. A necessary consequence of this notion is that the A-ATPases are ATP syntheses. With the possible exception of the A-ATPase from Halobacterium salinarium. no A-ATPase has been demonstrated to synthesize ATP. The evidence for this case is dubious since ATP synthesis occurs only when conditions are distinctively unphysiological. We demonstrated that ATP synthesis in H.saccharovorum is inconsistent with the operation of an A-type ATPase. In order to determine if this phenomenon was unique to H. saccharovorum, ATP synthesis was examined in various extremely halophilic bacteria with the goal of ascertaining if it resembled what occurred in a. saccharovorum, or was consistent with the operation of an A-type ATPase. A-, V-, and F-type ATPases respond singularly to certain inhibitors. Therefore, the effect of these inhibitors on ATP synthesis in several extreme halophiles was determined. Inhibitors that either blocked or collapsed proton-gradients inhibited the steady state synthesis of ATP thus verifying that synthesis took place at the expense of a proton gradient. Azide, an inhibitor of F-ATPases inhibited ATP synthesis. Since the arginine-dependent synthesis of ATP, which occurs by way of substrate-level phosphorylation, was unaffected by azide, it was unlikely that azide acted as an "uncoupler." N -ethylmaleimide and nitrate, which inhibit V- and A-ATPases, either did not inhibit ATP synthesis or resulted in higher steady-state levels of ATP. These results suggest there are two types of proton-motive ATPases in the extreme halophiles (and presumably in other Archaea). One, the V-like enzyme which, provides protons that are subsequently used for solute translocation. The other ATPase is the familiar and ubiquitous F-ATPase that functions as a reversible proton pump and is the ATP Synthase in the extreme halophiles. Thus, while the suggested evolution of the proton -translocating ATPases accounts for the relationship among these ATPases, this scheme does not account for the presence of F-ATPases in the Archaea. Discounting lateral gene transfer, perhaps an F-type ATPase evolved before the eucaryal-archaeal and bacterial bifurcation. The presence of V-type ATPases in the Bacterial Domain is consistent with this suggestion. Finally, it is of interest to note that if an F-type ATPase appeared before the bifurcation, an endosymbiotic event need not be invoked to explain the presence of F-ATPases in the Eucarya.

  12. Anomalous swimming behavior of bacteria in nematic liquid crystals

    Science.gov (United States)

    Sokolov, Andrey; Zhou, Shuang; Lavrentovich, Oleg; Aranson, Igor

    2015-03-01

    Flagellated bacteria stop swimming in isotropic media of viscosity higher than 0.06kgm-1s-1. However, Bacillus Subtilis slows down by only about 30% in a nematic chromonic liquid crystal (CLC, 14wt% DSCG in water), where the anisotropic viscosity can be as high as 6kgm-1s-1. The bacteria velocity (Vb) is linear with the flagella rotation frequency. The phase velocity of the flagella Vf ~ 2Vb in LC, as compared to Vf ~ 10Vb in water. The flow generated by the bacteria is localized along the bacterial body axis, decaying slowly over tens of micrometers along, but rapidly over a few micrometers across this axis. The concentrated flow grants the bacteria new ability to carry cargo particles in LC, ability not seen in their habitat isotropic media. We attribute these anomalous features to the anisotropy of viscosity of the CLC, namely, the viscosities of splay and twist is hundreds times higher than that of bend deformation, which provides extra boost of swimming efficiency and enables the bacteria swim at considerable speed in a viscous medium. Our findings can potentially lead to applications such as particle transportation in microfluidic devices. A.S and I.A are supported by the US DOE, Office of Science, BES, Materials Science and Engineering Division. S.Z. and O.D.L are supported by NSF DMR 1104850, DMS-1434185.

  13. Impaired macrophage phagocytosis of bacteria in severe asthma

    Science.gov (United States)

    2014-01-01

    Background Bacteria are frequently cultured from sputum samples of severe asthma patients suggesting a defect in bacterial clearance from the airway. We measured the capacity of macrophages from patients with asthma to phagocytose bacteria. Methods Phagocytosis of fluorescently-labelled polystyrene beads, Haemophilus influenzae or Staphylococcus aureus by broncholaveolar lavage alveolar macrophages (AM) and by monocyte-derived macrophages (MDM) from non-asthmatics, mild-moderate and severe asthmatic patients was assessed using fluorimetry. Results There were no differences in phagocytosis of polystyrene beads by AMs or MDMs from any of the subject groups. There was reduced phagocytosis of Haemophilus influenzae and Staphylococcus aureus in MDMs from patients with severe asthma compared to non-severe asthma (p?formoterol did not suppress phagocytosis of bacteria by MDMs from any of the groups. Conclusions Persistence of bacteria in the lower airways may result partly from a reduced phagocytic capacity of macrophages for bacteria. This may contribute to increased exacerbations, airway colonization and persistence of inflammation. PMID:24972601

  14. Coevolution of CRISPR bacteria and phage in 2 dimensions

    Science.gov (United States)

    Han, Pu; Deem, Michael

    2014-03-01

    CRISPR (cluster regularly interspaced short palindromic repeats) is a newly discovered adaptive, heritable immune system of prokaryotes. It can prevent infection of prokaryotes by phage. Most bacteria and almost all archae have CRISPR. The CRISPR system incorporates short nucleotide sequences from viruses. These incorporated sequences provide a historical record of the host and predator coevolution. We simulate the coevolution of bacteria and phage in 2 dimensions. Each phage has multiple proto-spacers that the bacteria can incorporate. Each bacterium can store multiple spacers in its CRISPR. Phages can escape recognition by the CRISPR system via point mutation or recombination. We will discuss the different evolutionary consequences of point mutation or recombination on the coevolution of bacteria and phage. We will also discuss an intriguing ``dynamic phase transition'' in the number of phage as a function of time and mutation rate. We will show that due to the arm race between phages and bacteria, the frequency of spacers and proto-spacers in a population can oscillate quite rapidly.

  15. Alternative Ecology of Human Pathogenic Bacteria in Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    A. Nithya

    2014-01-01

    Full Text Available Outbreaks of illness due to human enteric pathogenic bacteria via fresh vegetables warrant intensive research on changing strategies of these bacteria in alterning their hosts for survival. The systemic infection of human pathogenic bacteria in plants and the plant growth stage at which they establish endophytic relationship is poorly understood. The issue is magnified in countries like India where the dietary habits are changing and consumption of fresh fruits and vegetables as salad has become a part in the everyday menu of most people. Most of the human pathogenic enteric bacteria are generally characterized by broad host ranges and these pathogens seem to exploit almost any change in human ecology that provides new opportunities for transmission. Because plants are not traditionally considered as hosts for human enteric pathogens, recent produce-associated outbreaks highlight important deficiencies in our understanding of the ecology of enteric pathogens outside of their human and animal hosts. This review focuses on understanding the human enteric pathogens that have developed abilities to colonize internal tissues of vegetables and fruits popularly consumed as salads, how and when do they enter plants and where do they localize in plant tissues. In addition, we have also highlighted the attempts made in detection and control of these bacteria in plant hosts. This understanding will help develop strategies towards vegetable food safety in a joint effort by agriculturalists, environmentalists, food processing agencies, whole salers and retailers, which will ultimately benefit every consumer.

  16. Biofilm bacteria: formation and comparative susceptibility to antibiotics.

    Science.gov (United States)

    Olson, Merle E; Ceri, Howard; Morck, Douglas W; Buret, Andre G; Read, Ronald R

    2002-04-01

    The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of micro-colonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms. PMID:11989739

  17. Screening of Nitrogen Fixing Endophytic Bacteria in Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Prathana Hongrittipun

    2014-05-01

    Full Text Available Nitrogen (N is an essential element for the growth and yield of rice. Some endophytic bacteria can fix N2 from the air and convert to nitrogen compounds that can be utilized by plants. In this study, endophytic bacteria were isolated from one-month-old seedlings of five rice (Oryza sativa L. varieties (Muey Nong 24, Muey Nong 25, Pathum Thani 1, Suphan Buri 1 and Chai Nat 1 growing without nitrogen fertilizer in the farmers’ field. One hundred and twenty-three isolates of endophytic bacteria were obtained from the roots, stems and leaves of these rice varieties. Nitrogenase activity of the bacteria in N-free culture medium was determined by acetylene reduction assay. Seven isolates of the bacteria with highest nitrogenase activity were identified by phylogenetic analysis of the 16S rRNA genes, and found to belong to Burkholderia cepacia (CS5, Citrobacter sp. (CR9, Citrobacter sp. (SS5, Citrobacter sp. (SS6, Bacillus amyloliquefaciens (25R14, B. amyloliquefaciens (SR1 and B. thuringiensis (25R2. Inoculation of Bu. cepacia (CS5 and Citrobacter sp. (CR9 to the seedlings of local rice variety (Muey Nong 24 significantly increased nitrogen concentration in the roots of rice.

  18. Non-thermal plasma mills bacteria: Scanning electron microscopy observations

    Science.gov (United States)

    Lunov, O.; Churpita, O.; Zablotskii, V.; Deyneka, I. G.; Meshkovskii, I. K.; Jäger, A.; Syková, E.; Kubinová, Š.; Dejneka, A.

    2015-02-01

    Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin-stained rat skin sections from plasma-treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

  19. Distribution, organization, and ecology of bacteria in chronic wounds

    DEFF Research Database (Denmark)

    Kirketerp-MØller, Klaus; Jensen, Peter Ø

    2008-01-01

    Between 1 and 2% of the population in the developed world experiences a nonhealing or chronic wound characterized by an apparent arrest in a stage dominated by inflammatory processes. Lately, research groups have proposed that bacteria might be involved in and contribute to the lack of healing of these wounds. To investigate this, we collected and examined samples from chronic wounds obtained from 22 different patients, all selected because of suspicion of Pseudomonas aeruginosa colonization. These wound samples were investigated by standard culturing methods and peptide nucleic acid-based fluorescence in situ hybridization (PNA FISH) for direct identification of bacteria. By means of the culturing methods, Staphylococcus aureus was detected in the majority of the wounds, whereas P. aeruginosa was observed less frequently. In contrast, using PNA FISH, we found that a large fraction of the wounds contained P. aeruginosa. Furthermore, PNA FISH revealed the structural organization of bacteria in the samples. It appeared that P. aeruginosa aggregated as microcolonies imbedded in the matrix component alginate, which is a characteristic hallmark of the biofilm mode of growth. The present investigation suggests that bacteria present within these wounds tend to be aggregated in microcolonies imbedded in a self-produced matrix, characteristic of the biofilm mode of growth. Additionally, we must conclude that there exists no good correlation between bacteria detected by standard culturing methods and those detected by direct detection methods such as PNA FISH. This strongly supports the development of new diagnostic and treatment strategies for chronic wounds.

  20. Distribution, organization and ecology of bacteria in chronic wounds

    DEFF Research Database (Denmark)

    Kirketerp-MØller, Klaus; Jensen, Peter Ø.

    2008-01-01

    Between 1 and 2% of the population in the developed world experiences a nonhealing or chronic wound characterized by an apparent arrest in a stage dominated by inflammatory processes. Lately, research groups have proposed that bacteria might be involved in and contribute to the lack of healing of these wounds. To investigate this, we collected and examined samples from chronic wounds obtained from 22 different patients, all selected because of suspicion of Pseudomonas aeruginosa colonization. These wound samples were investigated by standard culturing methods and peptide nucleic acid-based fluorescence in situ hybridization (PNA FISH) for direct identification of bacteria. By means of the culturing methods, Staphylococcus aureus was detected in the majority of the wounds, whereas P. aeruginosa was observed less frequently. In contrast, using PNA FISH, we found that a large fraction of the wounds contained P. aeruginosa. Furthermore, PNA FISH revealed the structural organization of bacteria in the samples. It appeared that P. aeruginosa aggregated as microcolonies imbedded in the matrix component alginate, which is a characteristic hallmark of the biofilm mode of growth. The present investigation suggests that bacteria present within these wounds tend to be aggregated in microcolonies imbedded in a self-produced matrix, characteristic of the biofilm mode of growth. Additionally, we must conclude that there exists no good correlation between bacteria detected by standard culturing methods and those detected by direct detection methods such as PNA FISH. This strongly supports the development of new diagnostic and treatment strategies for chronic wounds.