Distributions of model microorganisms along an estuarine gradient
Carbonero, Franck (2010) Distributions of model microorganisms along an estuarine gradient. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b2482438~S15
Microbial ecology is the younger sub-discipline of ecology, but its scope is clearly
immense. Microorganisms’ specificities represent a major hurdle to the application
of traditional ecological approaches. Recently, the opportunity to apply ecological
principles to microorganisms was suggested. It is assumed that existing principles
might apply, but that they are probably also driven by specific principles.
Microorganisms have varying metabolic abilities and are classified as generalists or
specialists. We hypothesised that contrasting metabolic properties may drive
genotypic distribution. Model generalist and specialist genera were selected and
distribution patterns along the salinity gradient of the River Colne estuary studied.
Two models were studied in detail, Desulfobulbus a versatile sulphate-reducing
bacterial (SRB) genus and Methanosaeta, a strict aceticlastic methanogenic archaea
(MA). Isolation of Methanosaeta was attempted in order to link phenotypes to
genotypic distribution. Two other models were also studied: Methanosarcina the
most versatile MA genus and Desulfobacter a metabolically restricted SRB genus.
Denaturing gel gradient electrophoresis (DGGE) and clone libraries analyses were
used to determine genotypic distribution patterns.
Methanosaeta have proven to be highly recalcitrant to isolation. Adjustments to
commonly used anaerobic culturing methods allowed the obtention of Methanosaeta
colonies. In contrast to previous studies, colonies were successfully transferred into
liquid medium, and growth of pure clonal cultures confirmed.
Desulfobulbus genotypic distribution pattern was previously shown to be sequential
along the estuary. Contrastingly, Methanosaeta genotypic distribution pattern was
found to be monotonic. Furthermore, active genotypes distribution was also found
monotonic, with an apparent general increase in activity with decreasing salinity.
Distribution patterns of the four different genera confirmed this trend. The
generalists were both shown to have sequential distribution patterns. Contrastingly,
the specialists were both shown to have monotonic distribution patterns.
These results confirm the hypothesis that genotypic distribution patterns microbial
communities structure are strongly driven by microorganisms’ metabolic properties
and adaptative potential.
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||Q Science > QR Microbiology|
|Library of Congress Subject Headings (LCSH):||Microbial ecology, Bacteria -- Genetics, Bacteria -- Metabolism, Microorganisms -- England -- Essex -- Colne River|
|Official Date:||June 2010|
|Institution:||University of Warwick|
|Theses Department:||Department of Biological Sciences|
|Sponsors:||European Union (EU) (MEXT-CT-2005-024112)|
|Extent:||xi, 124,  leaves : ill., charts|
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