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Université de Neuchâtel

Soil Microbial Community Changes in Wooded Mountain Pastures due to Simulated Effects of Cattle Grazing

Kohler, Florian ; Hamelin, Jérôme ; Gillet, François ; Gobat, Jean-Michel ; Buttler, Alexandre

In: Plant and Soil, 2005, vol. 278, no. 1-2, p. 327-340

The effect of cattle activity on pastures can be subdivided into three categories of disturbances: herbage removal, dunging and trampling. The objective of this study was to assess separately or in combination the effect of these factors on the potential activities of soil microbial communities and to compare these effects with those of soil properties and plant composition or biomass. Controlled...

Université de Neuchâtel

How elevated pCO2 modifies total and metabolically active bacterial communities in the rhizosphere of two perennial grasses grown under field conditions

Jossi, Maryline ; Fromin, Nathalie ; Tarnawski, Sonia ; Kohler, Florian ; Gillet, François ; Aragno, Michel ; Hamelin, Jérôme

In: FEMS Microbiology Ecology, 2006, vol. 55, no. 3, p. 339-350

The response of total (DNA-based analysis) and active (RNA-based analysis) bacterial communities to a pCO2 increase under field conditions was assessed using two perennial grasses: the nitrophilic Lolium perenne and the oligonitrophilic Molinia coerulea. PCR- and reverse transcriptase-PCR denaturing gradient gel electrophoresis analysis of 16S rRNA genes generated...

Université de Neuchâtel

nifH gene diversity in the bacterial community associated with the rhizosphere of Molinia coerulea, an oligonitrophilic perennial grass

Hamelin, Jérôme ; Fromin, Nathalie ; Tarnawski, Sonia ; Teyssier-Cuvelle, Sylvie ; Aragno, Michel

In: Environmental Microbiology, 2002, vol. 4, no. 8, p. 477-481

Rhizosphere associative dinitrogen fixation could be a valuable source of nitrogen in many nitrogen limited natural ecosystems, such as the rhizosphere of Molinia coerulea, a hemicryptophytic perennial grass naturally occurring in contrasted oligonitrophilic soils. The diversity of the dinitrogen-fixing bacteria associated with this environment was assessed by a cloning–sequencing...

Université de Neuchâtel

Statistical analysis of denaturing gel electrophoresis (DGE) fingerprinting patterns

Fromin, Nathalie ; Hamelin, Jérôme ; Tarnawski, Sonia ; Roesti, David ; Jourdain-Miserez, K. ; Teyssier-Cuvelle, Sylvie ; Gillet, F. ; Aragno, Michel ; Rossi, Pierre

In: Environmental Microbiology, 2002, vol. 4, no. 11, p. 634-643

Technical developments in molecular biology have found extensive applications in the field of microbial ecology. Among these techniques, fingerprinting methods such as denaturing gel electrophoresis (DGE, including the three options: DGGE, TGGE and TTGE) has been applied to environmental samples over this last decade. Microbial ecologists took advantage of this technique, originally developed for...

Université de Neuchâtel

Examination of Gould’s modified S1 (mS1) selective medium and Angle’s non-selective medium for describing the diversity of Pseudomonas spp. in soil and root environments

Tarnawski, Sonia Estelle ; Hamelin, Jérôme ; Locatelli, Laurent ; Aragno, Michel ; Fromin, Nathalie

In: FEMS Microbiology Ecology, 2003, vol. 45, p. 97-104

Studies on the diversity of environmental culturable Pseudomonas populations are dependent on the isolation procedure. This procedure includes the use of selective media which may influence the recovery of strains and thus the diversity described. In this study, we assessed the use of two agar isolation media for describing the diversity of soil- and root-inhabiting Pseudomonas...

Université de Neuchâtel

Specific PCR Amplification for the Genus Pseudomonas Targeting the 3′ Half of 16S rDNA and the Whole 16S–23S rDNA Spacer

Locatelli, Laurent ; Tarnawski, Sonia Estelle ; Hamelin, Jérôme ; Rossi, Pierre ; Aragno, Michel ; Fromin, Nathalie

In: Systematic and Applied Microbiology, 2002, vol. 25, p. 220-227

A PCR protocol was developed for the selective amplification of a segment of the ribosomal RNA operon in Pseudomonas strains. Two specific conserved sequences suitable for PCR priming were identified in the middle of the 16S rDNA and at the very beginning of the 23S rDNA respectively. As a result, amplified region includes the 3′ half of the 16S rDNA with the whole 16S–23S rRNA...

Université de Neuchâtel

Phenotypic structure of Pseudomonas populations is altered under elevated pCO2 in the rhizosphere of perennial grasses

Tarnawski, Sonia Estelle ; Hamelin, Jérôme ; Jossi, M. ; Aragno, Michel ; Fromin, Nathalie

In: Soil Biology and Biochemistry, 2006, vol. 38, p. 1193-1201

The increasing atmospheric CO2 content (pCO2) is likely to modify the ecosystem functioning including rhizosphere bacteria that are directly dependent on rhizodeposition. This may include alteration of Pseudomonas populations that display phenotypic traits in relation with plant fitness. In the present study, 1228 Pseudomonas strains were isolated from the...

Université de Neuchâtel

Nitrogen fertiliser rate affects the frequency of nitrate-dissimilating Pseudomonas spp. in the rhizosphere of Lolium perenne grown under elevated pCO2 (Swiss FACE)

Fromin, Nathalie ; Tarnawski, Sonia Estelle ; Roussel-Delif, L. ; Hamelin, Jérôme ; Baggs, E.M. ; Aragno, Michel

In: Soil Biology and Biochemistry, 2005, vol. 37, p. 1962-1965

The effect of elevated pCO2 (60 Pa) on the frequency of nitrate-dissimilating Pseudomonas (NDP) was investigated in the rhizosphere of fertilised Lolium perenne swards in the Swiss Free Air Carbon dioxide Enrichment (FACE) experiment. Numbers of cultivable root-associated Pseudomonas were greater under elevated (60 Pa) than under ambient (36 Pa) pCO2 in...