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PubMed2006

Variations of bacterial community structure in flooded paddy soil contaminated with herbicide quinclorac.

The denaturing gradient gel electrophoresis (DGGE) method was applied to determine the relative genetic complexity of microbial communities in flooded paddy soil treated with herbicide quinclorac (3,7-dichloro-8-quinoline-carboylic acid). The results obtained showed a significant effect of quinclorac on the development of bacterial populations in soils contaminated with different concentrations of the herbicide at the early time after application. In general, however, the number of populations of the same soil sample treated with the same concentration of the quinclorac differed obviously with increasing incubation time within the early 8 weeks. The scale of differences in banding patterns-showed that the microbial community structures of the quinclorac-treated and non-quinclorac-treated soils were not significantly different after 21 weeks of incubation. Quantification, as demonstrated in this paper, was studied by establishing dose-response relationships. Significant pattern variations were quantified. Prominent DGGE bands were excised, cloned and sequenced to gain insight into the identities of predominant bacterial populations. The majority of DGGE band sequences were related to bacterial genera Clostridium, Sphingobacterium, Xanthomonas and Rhodococcus.

Bacteria↗

PubMed2005

Bacterial community structure in kimchi, a Korean fermented vegetable food, as revealed by 16S rRNA gene analysis.

Kimchi is a traditional Korean food fermented from a variety of vegetables. We elucidated the microbial community structure of five commercially produced kimchis made from Chinese cabbage by examining culture-independent 16S rRNA gene clone libraries. Most of the clones (347 out of 348) belonged to lactic acid bacteria and included several species of the genera Lactobacillus, Leuconostoc and Weissella. Weissella koreensis was found in all the samples and predominated in three of them (42.6-82%). Leuconostoc gelidum, Leuconostoc gasicomitatum and Lactobacillus sakei were common in the remaining kimchi clone libraries (>34%). The composition of bacterial phylotypes in kimchi varied between samples. Our approach revealed different community structures from those reported in previous culture-dependent studies based on phenotypic identification methods. The culture-independent method used here proved to be efficient and accurate and showed that the bacterial communities in kimchi differ from those in other fermented vegetable foods.

Base Sequence↗

PubMed2004

Estuarine microbial food web patterns in a Lake Erie coastal wetland.

Composition and distribution of planktonic protists were examined relative to microbial food web dynamics (growth, grazing, and nitrogen cycling rates) at the Old Woman Creek (OWC) National Estuarine Research Reserve during an episodic storm event in July 2003. More than 150 protistan taxa were identified based on morphology. Species richness and microbial biomass measured via microscopy and flow cytometry increased along a stream-lake (Lake Erie) transect and peaked at the confluence. Water column ammonium (NH4+) uptake (0.06 to 1.82 microM N h(-1)) and regeneration (0.04 to 0.55 microM N h(-1)) rates, measured using 15NH4+ isotope dilution, followed the same pattern. Large light/dark NH4+ uptake differences were observed in the hypereutrophic OWC interior, but not at the phosphorus-limited Lake Erie site, reflecting the microbial community structural shift from net autotrophic to net heterotrophic. Despite this shift, microbial grazers (mostly choreotrich ciliates, taxon-specific growth rates up to 2.9 d(-1)) controlled nanophytoplankton and bacteria at all sites by consuming 76 to 110% and 56 to 97% of their daily production, respectively, in dilution experiments. Overall, distribution patterns and dynamics of microbial communities in OWC resemble those in marine estuaries, where plankton productivity increases along the river-sea gradient and reaches its maximum at the confluence.

Bacteria↗

PubMed1999

Changes in bacterial and eukaryotic community structure after mass lysis of filamentous cyanobacteria associated with viruses.

During an experiment in two laboratory-scale enclosures filled with lake water (130 liters each) we noticed the almost-complete lysis of the cyanobacterial population. Based on electron microscopic observations of viral particles inside cyanobacterial filaments and counts of virus-like particles, we concluded that a viral lysis of the filamentous cyanobacteria had taken place. Denaturing gradient gel electrophoresis (DGGE) of 16S ribosomal DNA fragments qualitatively monitored the removal of the cyanobacterial species from the community and the appearance of newly emerging bacterial species. The majority of these bacteria were related to the Cytophagales and actinomycetes, bacterial divisions known to contain species capable of degrading complex organic molecules. A few days after the cyanobacteria started to lyse, a rotifer species became dominant in the DGGE profile of the eukaryotic community. Since rotifers play an important role in the carbon transfer between the microbial loop and higher trophic levels, these observations confirm the role of viruses in channeling carbon through food webs. Multidimensional scaling analysis of the DGGE profiles showed large changes in the structures of both the bacterial and eukaryotic communities at the time of lysis. These changes were remarkably similar in the two enclosures, indicating that such community structure changes are not random but occur according to a fixed pattern. Our findings strongly support the idea that viruses can structure microbial communities.

Animals↗

PubMed1985

Biomass and community structure of the abyssal microbiota determined from the ester-linked phospholipids recovered from Venezuela Basin and Puerto Rico Trench sediments.

Extractible phospholipid fatty acids of abyssal sediment cores from three stations in the Venezuela Basin, transects between them, and a station in the Puerto Rico Trench were analyzed to determine microbial biomass and community composition. Results were compared to abyssal sediments from an area of high-energy boundary currents in the North Atlantic, and estuarine sediments from Apalachee Bay, Florida. Venezuela Basin and Puerto Rico Trench sediments were characterize by low microbial biomass, measured as phospholipid palmitic acid. Venezuela Basin sediments of three different sedimentary regimes showed a remarkably similar microbial community structure, as characterized by fatty acid profiles. Prokaryotic organisms dominated the microbial community, and fatty acids believed to be signatures of anaerobic organisms were present in greater proportions in Venezuela Basin and Puerto Rico Trench sediments than in either the North Atlantic abyssal sediments or shallow-water estuarine sediments.

Biomass↗

PubMed2003

Effects of temperature and fertilizer on activity and community structure of soil ammonia oxidizers.

We investigated the effect of temperature on the activity of soil ammonia oxidizers caused by changes in the availability of ammonium and in the microbial community structure. Both short (5 days) and long (6.5, 16 and 20 weeks) incubation of an agricultural soil resulted in a decrease in ammonium concentration that was more pronounced at temperatures between 10 and 25 degrees C than at either 4 degrees C or 30-37 degrees C. Consistently, potential nitrification was higher between 10 and 25 degrees C than at either 4 degrees C or 37 degrees C. However, as long as ammonium was not limiting, release rates of N2O increased monotonously between 4 and 37 degrees C after short-term temperature adaptation, with nitrification accounting for about 35-50% of the N2O production between 4 and 25 degrees C. In order to see whether temperature may also affect the community structure of ammonia oxidizers, we studied moist soil during long incubation at low and high concentrations of commercial fertilizer. The soil was also incubated in buffered (pH 7) slurry amended with urea. Communities of ammonia oxidizers were assayed by denaturant gradient gel electrophoresis (DGGE) of the amoA gene coding for the alpha subunit of ammonia monooxygenase. We found that a polymerase chain reaction (PCR) system using a non-degenerated reverse primer (amoAR1) gave the best results. Community shifts occurred in all soil treatments after 16 weeks of incubation. The community shifts were obviously influenced by the different fertilizer treatments, indicating that ammonium was a selective factor for different ammonia oxidizer populations. Temperature was also a selective factor, in particular as community shifts were also observed in the soil slurries, in which ammonium concentrations and pH were better controlled. Cloning and sequencing of selected DGGE bands indicated that amoA sequences belonging to Nitrosospira cluster 1 were dominant at low temperatures (4-10 degrees C), but were absent after long incubation at low fertilizer treatment. Sequences of Nitrosospira cluster 9 could only be detected at low ammonium concentrations, whereas those of Nitrosospira cluster 3 were found at most ammonium concentrations and temperatures, although individual clones of this cluster exhibited trends with temperature. Obviously, ammonia oxidizers are able to adapt to soil conditions by changes in the community structure if sufficient time (several weeks) is available.

Ammonia↗

PubMed2007

Microbial community dynamics during assays of harbour oil spill bioremediation: a microscale simulation study.

AIMS: Microcosm experiments simulating an oil spill event were performed to evaluate the response of the natural microbial community structure of Messina harbour seawater following the accidental load of petroleum. METHODS AND RESULTS: An experimental harbour seawater microcosm, supplemented with nutrients and crude oil, was monitored above 15 days in comparison with unpolluted ones (control microcosms). Bacterial cells were counted with a Live/Dead BacLight viability kit; leucine aminopeptidase, beta-glucosidase, alkaline phosphatase, lipase and esterase enzymes were measured using fluorogenic substrates. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil addition stimulated an increase of the total bacterial abundance, leucine aminopeptidase and phosphatase activity rates, as well as a change in the community structure. This suggested a prompt response of micro-organisms to the load of petroleum hydrocarbons. CONCLUSIONS: The present study on the viability, specific composition and metabolic characteristics of the microbial community allows a more precise assessment of oil pollution. Both structural and functional parameters offer interesting perspectives as indicators to monitor changes caused by petroleum hydrocarbons. SIGNIFICANCE AND IMPACT OF THE STUDY: A better knowledge of microbial structural successions at oil-polluted sites is essential for environmental bioremediation. Data obtained in microcosm studies improve our understanding of natural processes occurring during oil spills.

Alcanivoraceae↗

PubMed2003

Sampling strategy in molecular microbial ecology: influence of soil sample size on DNA fingerprinting analysis of fungal and bacterial communities.

Assessing soil microbial community structure by the use of molecular techniques requires a satisfactory sampling strategy that takes into account the high microbial diversity and the heterogeneous distribution of microorganisms in the soil matrix. The influence of the sample size of three different soil types (sand, silt and clay soils) on the DNA yield and analysis of bacterial and fungal community structure were investigated. Six sample sizes from 0.125 g to 4 g were evaluated. The genetic community structure was assessed by automated ribosomal intergenic spacer analysis (A-RISA fingerprint). Variations between bacterial (B-ARISA) and fungal (F-ARISA) community structure were quantified by using principal component analysis (PCA). DNA yields were positively correlated with the sample size for the sandy and silty soils, suggesting an influence of the sample size on DNA recovery, whereas no correlation was observed in the clay soil. B-ARISA was shown to be consistent between the different sample sizes for each soil type indicating that the sampling procedure has no influence on the assessment of bacterial community structure. On the contrary for F-ARISA profiles, strong variations were observed between replicates of the smaller samples (<1 g). Principal component analysis analysis revealed that sampling aliquots of soil > or =1 g are required to obtain robust and reproducible fingerprinting analysis of the genetic structure of fungal communities. However, the smallest samples could be adequate for the detection of minor populations masked by dominant ones in larger samples. The sampling strategy should therefore be different according to the objectives: rather large soil samples (> or =1 g) for a global description of the genetic community structure, or a large number of small soil samples for a more complete inventory of microbial diversity.

Bacteria↗

PubMed2002

Functional and structural adaptations of bacterial communities growing on particulate substrates under stringent nutrient limitation.

Biomass recycle reactors (BRRs) were used as a model system to study the functional and structural adaptations of mixed bacterial communities in response to the imposition of increasingly severe nutrient limitation. BRRs were fed synthetic media containing either spinach homogenate or autoclaved yeast cells to simulate the complex mixtures of particulate carbon sources that are often present in nature. In the BRRs fed spinach homogenate, the biomass (measured as particulate protein) exhibited a physiological response similar to previous studies as detected by 40-80% reductions in respiratory potential and by relatively stable catabolic ectoenzyme activities. Concomitant adaptations in bacterial community structure were detected by PCR-DGGE and RT-PCR-DGGE of 16S rDNA and 16S rRNA fragments, respectively. The microbial community structure was dynamic even after the biomass had reached a quasi-steady state with respect to physiological measurements. In the BRRs fed yeast cells, respiratory potentials increased 2- to 5-fold during the initial portion of the BRR run and alpha-glucosidase and beta-glucosidase activities increased 2- to 4-fold. Substantial bacterial community shifts were also detected in both the rDNA and rRNA profiles, indicating that this community was also structurally dynamic. These experiments suggest that phylogenetically different bacteria sustained the functional activities in these ecosystems in response to increasingly stringent nutrient limitation.

Bacteria↗

PubMed2006

Interrelationships between Dunaliella and halophilic prokaryotes in saltern crystallizer ponds.

Thanks to their often very high population densities and their simple community structure, saltern crystallizer ponds form ideal sites to study the behavior of halophilic microorganisms in their natural environment at saturating salt concentrations. The microbial community is dominated by square red halophilic Archaea, recently isolated and described as Haloquadratum walsbyi, extremely halophilic red rod-shaped Bacteria of the genus Salinibacter, and the unicellular green alga Dunaliella as the primary producer. We review here, the information available on the microbial community structure of the saltern crystallizer brines and the interrelationships between the main components of their biota. As Dunaliella produces massive amounts of glycerol to provide osmotic stabilization, glycerol is often postulated to be the most important source of organic carbon for the heterotrophic prokaryotes in hypersaline ecosystems. We assess here, the current evidence for the possible importance of glycerol and other carbon sources in the nutrition of the Archaea and the Bacteria, the relative contribution of halophilic Bacteria and Archaea to the heterotrophic activity in the brines, and other factors that determine the nature of the microbial communities that thrive in the salt-saturated brines of saltern crystallizer ponds.

Adaptation, Physiological↗

PubMed2002

Soil microbial community of abandoned sand fields.

Microbiological evaluation of sandy grassland soils from two different stages of secondary succession on abandoned fields (4 and 8 years old fallow) was carried out as a part of research focused on restoration of semi-natural vegetation communities in Kiskunság National Park in Hungary. There was an apparent total N and organic C enrichment, stimulation of microbial growth and microbial community structure change on fields abandoned by agricultural practice (small family farm) in comparison with native undisturbed grassland. A successional trend of the microbial community was found after 4 and 8 years of fallow-lying soil. It consisted in a shift of r-survival strategy to more efficient C economy, in a decrease of specific respiration and metabolic activity, forced accumulation of storage bacterial compounds and increased fungal distribution. The composition of microbial phospholipid fatty acids mixture of soils abandoned at various times was significantly different.

Agriculture↗

PubMed2004

Effect of pyocyanin on a crude-oil-degrading microbial community.

Pseudomonas aeruginosa is an n-alkane degrader that is frequently isolated from petroleum-contaminated sites and produces factors that enhance its competitiveness and survival in many environments. In this study, one such factor, pyocyanin, has been detected in an oil-degrading culture containing P. aeruginosa and is a redox-active compound capable of inhibiting microbial growth. To examine the effects of pyocyanin further, an oil-degrading culture was grown with and without 9.5 microM pyocyanin and microbial community structure and oil degradation were monitored for 50 days. Denaturing gradient gel electrophoresis (DGGE) analysis of cultures revealed a decrease in the microbial community diversity in the pyocyanin-amended cultures compared to that of the unamended cultures. Two members of the microbial community in pure culture exhibited intermediate and high sensitivities to pyocyanin corresponding to intermediate and low levels of activity for the antioxidant enzymes catalase and superoxide dismutase, respectively. Another member of the community that remained constant in the DGGE gels over the 50-day culture incubation period exhibited no sensitivity to pyocyanin, corresponding to a high level of catalase and superoxide dismutase when examined in pure culture. Pyocyanin also affected the overall degradation of the crude oil. At 50 days, the culture without pyocyanin had decreased polycyclic aromatic hydrocarbons compared to the pyocyanin-amended culture, with a specific reduction in the degradation of dibenzothiophenes, naphthalenes, and C(29) and C(30) hopanes. This study demonstrated that pyocyanin influenced the diversity of the microbial community and suggests the importance of understanding how interspecies interactions influence the degradation capability of a microbial community.

Bacteria↗

PubMed2005

Evidence of intense archaeal and bacterial methanotrophic activity in the Black Sea water column.

In the northwestern Black Sea, methane oxidation rates reveal that above shallow and deep gas seeps methane is removed from the water column as efficiently as it is at sites located off seeps. Hence, seeps should not have a significant impact on the estimated annual flux of approximately 4.1 x 10(9) mol methane to the atmosphere [W. S. Reeburgh, B. B. Ward, S. C. Wahlen, K. A. Sandbeck, K. A. Kilatrick, and L. J. Kerkhof, Deep-Sea Res. 38(Suppl. 2):S1189-S1210, 1991]. Both the stable carbon isotopic composition of dissolved methane and the microbial community structure analyzed by fluorescent in situ hybridization provide strong evidence that microbially mediated methane oxidation occurs. At the shelf, strong isotope fractionation was observed above high-intensity seeps. This effect was attributed to bacterial type I and II methanotrophs, which on average accounted for 2.5% of the DAPI (4',6'-diamidino-2-phenylindole)-stained cells in the whole oxic water column. At deep sites, in the oxic-anoxic transition zone, strong isotopic fractionation of methane overlapped with an increased abundance of Archaea and Bacteria, indicating that these organisms are involved in the oxidation of methane. In underlying anoxic water, we successfully identified the archaeal methanotrophs ANME-1 and ANME-2, eachof which accounted for 3 to 4% of the total cell counts. ANME-1 and ANME-2 appear as single cells in anoxicwater, compared to the sediment, where they may form cell aggregates with sulfate-reducing bacteria (A. Boetius, K. Ravenschlag, C. J. Schubert, D. Rickert, F. Widdel, A. Giesecke, R. Amann, B. B. Jørgensen, U. Witte, and O. Pfannkuche, Nature 407:623-626, 2000; V. J. Orphan, C. H. House, K.-U. Hinrichs, K. D. McKeegan, and E. F. DeLong, Proc. Natl. Acad. Sci. USA 99:7663-7668, 2002).

Archaea↗

PubMed2000

Effect of inoculation of a TOL plasmid containing mycorrhizosphere bacterium on development of Scots pine seedlings, their mycorrhizosphere and the microbial flora in m-toluate-amended soil.

The purpose of this study was to evaluate the influence of introduced bacteria containing a contaminant degrading plasmid on the growth and survival of pine seedlings and mycorrhizosphere microbial flora in contaminated soil. The Pseudomonas fluorescens strain OS81, originally isolated from fungal hyphae in contaminated soil, was supplied with the TOL plasmid pWW0::Km (to generate OS81(pWW0::Km)) and inoculated in humus-soil microcosms with and without pine seedlings mycorrhized with Suillus bovinus. After 3 months of regular treatment with m-toluate (mTA) solutions, the introduced catabolic plasmid was found to be disseminated in the indigenous bacterial population of both mycorrhizosphere and soil uncolonized by the fungus. Transconjugants were represented by bacteria of the genera Pseudomonas and Burkholderia and their number correlated positively with the concentration of mTA applied. Indigenous mTA degrading bacteria with low similarity to Burkholderia species were also enriched in microcosms. They were mostly associated with mycorrhizal soil or fungal structures and virtually absent in microcosms without pines. The total number of Tol(+) bacteria was higher in mycorrhizospheric soil compared with bulk soil. Inoculation with P. fluorescens OS81(pWW0::Km) had a positive effect on the development of roots and fungus in contaminated soil. Both inoculation with the P. fluorescens OS81(pWW0::Km) and mTA contamination as well as the presence of mycorrhized pine roots and fungal hyphae had an effect on the microbial community structure of soil as measured by carbon source oxidation patterns. However, the impact of mTA on the microbial community was more prominent. The study indicates that an effect on plant and fungal development can be obtained by manipulating the mycorrhizosphere. Both introduction of the bacterium carrying the degradative plasmid and the plasmid itself are likely to have a positive effect not only on the organisms involved, but also on bioremediation of contaminated soil, a factor that was not directly monitored here.

Journal Article↗

PubMed2001

Impact of fumigants on soil microbial communities.

Agricultural soils are typically fumigated to provide effective control of nematodes, soilborne pathogens, and weeds in preparation for planting of high-value cash crops. The ability of soil microbial communities to recover after treatment with fumigants was examined using culture-dependent (Biolog) and culture-independent (phospholipid fatty acid [PLFA] analysis and denaturing gradient gel electrophoresis [DGGE] of 16S ribosomal DNA [rDNA] fragments amplified directly from soil DNA) approaches. Changes in soil microbial community structure were examined in a microcosm experiment following the application of methyl bromide (MeBr), methyl isothiocyanate, 1,3-dichloropropene (1,3-D), and chloropicrin. Variations among Biolog fingerprints showed that the effect of MeBr on heterotrophic microbial activities was most severe in the first week and that thereafter the effects of MeBr and the other fumigants were expressed at much lower levels. The results of PLFA analysis demonstrated a community shift in all treatments to a community dominated by gram-positive bacterial biomass. Different 16S rDNA profiles from fumigated soils were quantified by analyzing the DGGE band patterns. The Shannon-Weaver index of diversity, H, was calculated for each fumigated soil sample. High diversity indices were maintained between the control soil and the fumigant-treated soils, except for MeBr (H decreased from 1.14 to 0.13). After 12 weeks of incubation, H increased to 0.73 in the MeBr-treated samples. Sequence analysis of clones generated from unique bands showed the presence of taxonomically unique clones that had emerged from the MeBr-treated samples and were dominated by clones closely related to Bacillus spp. and Heliothrix oregonensis. Variations in the data were much higher in the Biolog assay than in the PLFA and DGGE assays, suggesting a high sensitivity of PLFA analysis and DGGE in monitoring the effects of fumigants on soil community composition and structure. Our results indicate that MeBr has the greatest impact on soil microbial communities and that 1,3-D has the least impact.

Allyl Compounds↗

PubMed2004

Responses of active bacterial and fungal communities in soils under winter wheat to different fertilizer and pesticide regimens.

The composition of the active microbial (bacterial and fungal) soil community in an arable wheat field subjected to different management practices was examined at five times during a 1-year period. Field sections were fertilized either at good agricultural practice (GAP) levels or at reduced levels (0.5x GAP) and were inoculated with vesicular arbuscular mycorrhizae (VAM) at the same time. Field subsections were treated either with or without pesticides. Changes in the active microbial communities were investigated by denaturing gradient gel electrophoresis analysis of reverse transcription-PCR-amplified 16S and 18S rRNA. Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components. Between-sample microbial heterogeneity decreased under a mature crop in the summer but increased following harvesting and plowing. Although similar overall trends were seen for the two microbial components, sample variability was greater for the fungal community than for the bacterial community. The greatest management effects were due to GAP fertilization, which caused increases in the bacterial numbers in the total and culturable communities. Microbial biomass similarly increased. GAP fertilization also caused large shifts in both the active bacterial community structure and the active fungal community structure and additionally resulted in a decrease in the heterogeneity of the active bacterial community. Pesticide addition did not significantly affect bacterial numbers or heterogeneity, but it led to major shifts in the active soil bacterial community structure. PCR primers specific for Glomales 25S rRNA genes were used to monitor the VAM population following inoculation. Glomales were detected initially only in VAM-inoculated field sections but were subsequently detected in noninoculated field sections as the season progressed. After plowing, the level of Glomales was reduced in noninoculated field sections but remained high in VAM-inoculated field sections. Inoculation of VAM correlated with elevated soil phosphate and carbon levels.

Agriculture↗

PubMed1999

Functional and Structural Responses of a Degradative Microbial Community to Substrates with Varying Degrees of Complexity in Chemical Structure.

Abstract The objective of the present study was to determine whether cultivation of a degradative community on substrates with varying degrees of chlorination and complexity in chemical structure, as well as cultivation in batch and flow cell culture, would alter the community's functional capability. The community was isolated from oil-contaminated soil and maintained in the laboratory on 2,4,6-trichlorobenzoic acid for 5 months before its ability to grow on 15 different chemicals as sole carbon source was evaluated in batch and flow cell systems. While the community could grow and develop biofilms in flow cells on all the substrates, only 11 of the 15 substrates could support growth in batch culture. Although biofilm development was less extensive on chemicals such as pentachlorophenol (2.09% average area covered by biofilm; average biofilm depth = 3 µm) than on 2,4,6-trichlorobenzoic acid (50.84% area covered; biofilm depth = 6.4 µm), no correlation was observed between the degree of chlorination, or number of rings, and the number of planktonic cells or biofilm biomass. In contrast, physicochemical characteristics such as the octanol/water partition coefficient had a significant effect on the development of biofilm biomass. In the case of planktonic communities, the degree of chlorination and ring number also had no effect on the BIOLOG carbon utilization profiles of the resulting communities. Although the sessile communities generally clustered separately from their planktonic counterparts, principal component analysis of carbon utilization profiles of the sessile communities showed different grouping between growth on chlorinated and nonchlorinated substrates. Analysis of the degradative community maintained on 2,4,6-trichlorobenzoic acid over an extended period further showed that adaptation to a new chemical environment is a rather slow process, since the substrate utilization profiles did not stabilize even after 12 months. These results demonstrate the flexibility in metabolic ability and community structure found in microbial communities.http://link.springer-ny.com/link/service/journals/00248/bibs/38n3p215.html</hea

Journal Article↗

PubMed1998

Change in bacterial community during biodegradation of aniline.

The response of river water microbial communities to chemical compounds was monitored under laboratory conditions using aniline as a model. Bacteria were collected from unpolluted and polluted sites. Bacterial abundance (plate and total direct counting) and its relation to aniline biodegradation was examined. Colony hybridization with 16S rRNA oligonucleotide probes was used to study the changes in microbial community structure during biodegradation of aniline. The changes in bacterial abundance and community structure were related to biodegradation of aniline. Burkholderia-Pseudomonas (rRNA group III), an authentic Alcaligenes group became dominant despite the initial differences in the microbial communities, suggesting that these genera are the main aniline degraders in the aquatic environment.

Alcaligenes↗