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Bacteria Capable (bacteria + capable)
Selected AbstractsHexavalent uranium supports growth of Anaeromyxobacter dehalogenans and Geobacter spp. with lower than predicted biomass yieldsENVIRONMENTAL MICROBIOLOGY, Issue 11 2007Robert A. Sanford Summary The stimulation of bacteria capable of reducing soluble U(VI) to sparingly soluble U(IV) is a promising approach for containing U(VI) plumes. Anaeromyxobacter dehalogenans is capable of mediating this activity; however, its ability to couple U(VI) reduction to growth has not been established. Monitoring the increase in 16S rRNA gene copy numbers using quantitative real-time PCR (qPCR) in cultures provided with U(VI) as an electron acceptor demonstrated growth, and 7.7,8.6 × 106 cells were produced per ,mole of U(VI) reduced. This biomass yield was lower than predicted based on the theoretical free energy changes associated with U(VI)-to-U(IV) reduction. Lower than predicted growth yields with U(VI) as electron acceptor were also determined in cultures of Geobacter lovleyi and Geobacter sulfurreducens suggesting that U(VI) reduction is inefficient or imposes an additional cost to growing cells. These findings have implications for U(VI) bioremediation because Anaeromyxobacter spp. and Geobacter spp. contribute to radionuclide immobilization in contaminated subsurface environments. [source] Phylogeny of cyclic nitramine-degrading psychrophilic bacteria in marine sediment and their potential role in the natural attenuation of explosivesFEMS MICROBIOLOGY ECOLOGY, Issue 3 2004Jian-Shen Zhao Abstract Previously we reported on in situ mineralization of cyclic nitramine explosives including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in marine sediment from Halifax Harbour. In the present study, we isolated several novel psychrophilic bacteria from the sediment with optimal growth temperature at 10 or 15 °C. Phylogenetic analysis of their 16S rRNA genes identified the isolates as members of the gamma and delta subdivisions of Proteobacteria, Fusobacteria and Clostridiales. The isolates mineralized 3.7,45.2% of RDX (92 ,M) in 82 days of incubation at 10 °C under oxygen-limited or anaerobic conditions with the gamma subdivision isolates demonstrating the highest mineralization (45.2% of total C). Removal of RDX by all isolates was accompanied by the formation of all three nitroso derivatives, with the mono nitroso derivative (MNX) being the major one. Isolates of the delta proteobacteria and Fusobacteria removed HMX with concurrent formation of the mononitroso derivative (NO-HMX). Using resting cells of isolates of the gamma subdivision, methylenedinitramine (MEDINA) and 4-nitro-2,4-diazabutanal (NDAB) were detected, suggesting ring-cleavage following denitration of either RDX and/or its initially reduced product, MNX. These results clearly demonstrate that psychrophilic bacteria capable of degrading cyclic nitramines are present in the marine sediment, and might contribute to the in situ biodegradation and natural attenuation of the chemicals. [source] Presence of nanobacteria in psammoma bodies of ovarian cancer: evidence for pathogenetic role in intratumoral biomineralizationHISTOPATHOLOGY, Issue 6 2004G Hudelist Aims:, The presence of laminated, calcified extracellular debris known as psammoma bodies is a well-known histomorphological feature of ovarian adenocarcinomas and other human malignancies. Biomineralization has recently been found to be associated with a group of extremely small Gram-negative bacteria capable of precipitating calcium salts. The aim of the present study was to evaluate a possible pathogenic link between the development of psammoma bodies and nanobacteria infection. Material and results:, Immunohistochemical staining and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to analyse nanobacterial protein and gene expression in eight psammona body-containing adenocarcinomas and in 10 malignant ovarian tumours without signs of biomineralization. Nanobacterial proteins were detected in eight out of eight (100%) psammoma-positive tumour samples. Conversely, none of the 10 psammoma-negative tissues (0%) was positive for nanobacterial antigens. Furthermore, nanobacterial mRNA was detectable in all of the four tissues (100%) that contained psammoma bodies, but was absent in all 10 ovarian cystadenocarcinomas (0%) that were psammoma negative. Conclusions:, We found a 100% concordance between the expression of nanobacteria and the presence of psammoma bodies in malignant ovarian tumours. Several lines of evidence suggest the involvement of these organisms in the process of biomineralization. We therefore conclude that nanobacterial infection of malignant ovarian tissue contributes to mechanisms leading to the formation of calcified deposits known as psammoma bodies. [source] Low temperature bioremediation of oil-contaminated soil using biostimulation and bioaugmentation with a Pseudomonas sp. from maritime AntarcticaJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2005B. Stallwood Abstract Aims:, To identify native Antarctic bacteria capable of oil degradation at low temperatures. Methods and Results:, Oil contaminated and pristine soils from Signy Island (South Orkney Islands, Antarctica) were examined for bacteria capable of oil degradation at low temperatures. Of the 300 isolates cultured, Pseudomonas strain ST41 grew on the widest range of hydrocarbons at 4°C. ST41 was used in microcosm studies of low temperature bioremediation of oil-contaminated soils. Microcosm experiments showed that at 4°C the levels of oil degradation increased, relative to the controls, with (i) the addition of ST41 to the existing soil microbial population (bioaugmentation), (ii) the addition of nutrients (biostimulation) and to the greatest extent with (iii) a combination of both treatments (bioaugmentation and biostimulation). Addition of water to oil contaminated soil (hydration) also enhanced oil degradation, although less than the other treatments. Analysis of the dominant species in the microcosms after 12 weeks, using temporal temperature gradient gel electrophoresis, showed Pseudomonas species to be the dominant soil bacteria in both bioaugmented and biostimulated microcosms. Conclusions:, Addition of water and nutrients may enhance oil degradation through the biostimulation of indigenous oil-degrading microbial populations within the soil. However, bioaugmentation with Antarctic bacteria capable of efficient low temperature hydrocarbon degradation may enhance the rate of bioremediation if applied soon after the spill. Significance and Impact of the Study:, In the future, native soil bacteria could be of use in bioremediation technologies in Antarctica. [source] Adhesion of Staphylococcus aureus and Staphylococcus epidermidis to the EpiskinŽ reconstructed epidermis model and to an inert 304 stainless steel substrateJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2004G. Lerebour Abstract Aims:, The aim of this study was to evaluate the respective influence of the physicochemical interactions and the roughness involved in the first part of the biological substrate biocontamination. Methods and Results:, Therefore we compared the bioadhesion results obtained on the biological model substrate (EpiskinŽ) and on a commonly employed inert substrate (AISI 304 stainless steel), frequently used either in dermatology or in development of medical devices. The two studied strains presented different characteristics, both physicochemical and microbiological. Staphylococcus epidermidis, a relatively hydrophobic bacteria capable of exchanging interactions which are principally of the van der Waals type, adhered more to 304 steel than to the surface of reconstituted skin. As for S. aureus, an essentially basic, hydrophilic bacteria, was more adherent to EpiskinŽ (a bipolar, hydrophilic substrate) than to stainless steel (a unipolar, basic, hydrophilic substrate). Conclusions:, In the absence of electrostatic interactions, the adhesion of substrate-dependent bacteria to the surface of reconstituted skin was dependent upon the balance between ,LW, ,+ and ,,. Significance and Impact of the Study:, Consequently, so as to restrict microbial adhesion and reduce adhesive binding between micro-organisms and the surface of the skin, it would be preferable to render this substrate hydrophobic and apolar through the use of appropriate surface treatment. [source] Enrichment and identification of bacteria capable of reducing chemical oxygen demand of anaerobically treated molasses spent washJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004M. Ghosh Abstract Aims:, The aim of this study was to isolate and identify bacterial strains capable of using recalcitrant compounds of molasses spent wash as sole carbon source from the soils of abandoned sites of distillery effluent discharge and characterize their ability of reducing the chemical oxygen demand (COD) of the spent wash. Methods and Results:, The isolates were grouped into six haplotypes by amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR. The phylogenetic position of the representatives of the six main haplotypes strains was determined by 16S rDNA sequencing. They showed maximum similarity to six genera viz. Pseudomonas, Enterobacter, Stenotrophomonas, Aeromonas, Acinetobacter and Klebsiella. The extent of COD (44%) reduced collectively by the six strains was equal to that reduced individually by Aeromonas, Acinetobacter, Pseudomonas and Enterobacter. With spent wash as sole carbon source, the COD reducing strains grew faster at 37°C than 30°C. Conclusions:, Bacterial strains capable of degrading some of the recalcitrant compounds of anaerobically digested molasses spent wash can be isolated from the soils of abandoned sites of distillery effluent discharge. Biostimulation of these bacteria, which can degrade 44% of the carbon compounds of anaerobically digested molasses spent wash can be achieved by nitrogen fertilization and relatively higher temperature. Significance and Impact of the Study:, Supplementation of nitrogen source and controlling the temperature can be used in evolving strategies for in situ bioremediation of anaerobically digested spent wash from distilleries. [source] BEHAVIOR OF AVIRULENT YERSINIA PESTIS IN LIQUID WHOLE EGG AS AFFECTED BY STORAGE TEMPERATURE, ANTIMICROBIALS AND THERMAL PASTEURIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2010JOSHUA B. GURTLER ABSTRACT Yersinia spp. are psychrotrophic bacteria capable of growth at temperatures as low as ,2C, known to contaminate shell eggs and liquid eggs in the U.S.A. and South America. A study was performed to determine the thermal sensitivity of avirulent Yersinia pestis in liquid whole egg (LWE), evaluate the growth pattern of the bacterium in LWE at temperatures of 4,22C and assess the ability of 10 antimicrobial compounds to inhibit the growth of attenuated Y. pestis in LWE. The estimated decimal reduction values of avirulent Y. pestis in LWE at 54C (D54) were 1.39,1.58 min, and D60 values were 13.8 and 11.4 s by the addition of 0 and 965 IU of nisin (MP Biomedicals, LLC, Solon, OH), respectively. Low molecular weight chitosan (0.5%) and an activated lactoperoxidase system (2.18 U/mL) were ineffective at inhibiting growth of Y. pestis, while 500 IU/mL of nisin inhibited populations by up to 1 log cfu/mL at 4, 10 and 15C when compared with the control. Allyl isothiocyanate, diacetyl, diethyl dicarbonate, ethylenediaminetetraacetic acid, methylparaben, monolaurin and benzoyl peroxide inhibited the growth of attenuated Y. pestis when added at high levels. PRACTICAL APPLICATIONS The genus Yersinia does not currently pose a problem in pasteurized liquid egg products, although it has been isolated from eggs in the U.S.A. and Argentina. Yersiniae, which are psychrotrophic bacteria, can grow at temperatures as low as ,2C; therefore, incidental or intentional contamination of liquid whole egg (LWE) with Yersinia spp. could result in multiplication to high populations, even when stored under refrigeration (ca. 4C). We have shown that avirulent Yersinia pestis is able to multiply to populations of >2, 5 and 8 log cfu/mL in LWE at 4C within 6, 14 and 26 days, respectively. This study provides information that will be helpful in determining thermal and nonthermal means of controlling yersiniae in LWE products. [source] Cooperative biodegradation of geosmin by a consortium comprising three gram-negative bacteria isolated from the biofilm of a sand filter columnLETTERS IN APPLIED MICROBIOLOGY, Issue 4 2006D. Hoefel Abstract Aims:, To isolate and identify bacteria from a sand filter column capable of degrading the taste and odour compound, geosmin. In doing so, to investigate if these organisms degrade geosmin either individually or if an alternative mechanism is utilized. Methods and Results:, Geosmin-degrading bacteria from a biologically active sand filter column were enriched by their growth in a minimal medium supplemented with geosmin as the sole carbon source. By day 51, 21ˇ7 mg l,1 of geosmin had been degraded as determined by solid-phase microextraction gas chromatography/mass spectrometry, and was accompanied by a 2ˇ12 log10 increase in active bacterial numbers as measured using the BacLightTM bacterial viability kit and flow cytometric enumeration. During the onset of geosmin degradation, the predominance of three bacteria, most similar to previously cultured species of Sphingopyxis alaskensis, Novosphingobium stygiae and Pseudomonas veronii based on 16S rRNA gene sequences was detected by denaturing gradient gel electrophoresis. Subsequent isolation of these organisms revealed that degradation of geosmin, when present as either the sole carbon source (ranging from 40 ng l,1 to 20 mg l,1) or when spiked into sterile reservoir water (37 and 131 ng l,1), occurred only when all three isolates were present. None of the isolates was shown to be capable of degrading geosmin either individually or in any combination of two. Conclusions:, This study has reported, for the first time, the cooperative degradation of geosmin by a consortium comprising three gram-negative bacteria isolated from a biologically active sand filter column. Significance and Impact of the Study:, These results are important for researchers currently employing molecular-based approaches to further understand the biodegradation of geosmin by bacteria, as such studies may be complicated by the discovery of geosmin degradation occurring by a consortium. This study also advances the knowledge surrounding the types of bacteria capable of degrading the taste and odour compound, as investigations to date regarding this are limited. [source] | ||||||||||||||||||||||