A5020130283- Microbial Community Ecology and Physiology
- Wastewater Treatment and Nitrogen Removal
- Soil Carbon and Nitrogen Dynamics
- Legume Nitrogen Fixing Symbiosis
- Plant nutrient uptake and metabolism
- Protist diversity and phylogeny
- Soil and Water Nutrient Dynamics
- Genomics and Phylogenetic Studies
- Microbial Fuel Cells and Bioremediation
- Heavy metals in environment
- Agronomic Practices and Intercropping Systems
- Coastal wetland ecosystem dynamics
- Ammonia Synthesis and Nitrogen Reduction
- Peatlands and Wetlands Ecology
- Soil and Unsaturated Flow
- Environmental DNA in Biodiversity Studies
- Chromium effects and bioremediation
- Mycorrhizal Fungi and Plant Interactions
- Anaerobic Digestion and Biogas Production
- Clay minerals and soil interactions
- Pesticide and Herbicide Environmental Studies
- Nematode management and characterization studies
- Molecular Biology Techniques and Applications
- Marine and coastal ecosystems
- Microbial Metabolic Engineering and Bioproduction
Norwegian University of Life Sciences
2015-2024
Centre National de la Recherche Scientifique
1999-2002
Université Claude Bernard Lyon 1
2001-2002
Lund University
1991-2001
Ecologie Microbienne Lyon
1999
The phospholipid fatty acid (PLFA) pattern was analyzed in a forest humus and an arable soil experimentally polluted with Cd, Cu, Ni, Pb, or Zn at different concentrations. In both types, there were gradual changes the PLFA patterns for levels of metal contamination. similar irrespective which used, while due to Cu contamination differed from those other metals. Several PLFAs reacted similarly amendments two others showed responses. soils, pollution resulted decrease iso-branched i15:0 i17:0...
In recent years, several protocols based on the extraction of nucleic acids directly from soil matrix after lysis treatment have been developed for detection microorganisms in soil. Extraction efficiency has often evaluated recovery a specific gene sequence an organism inoculated into The aim present investigation was to improve extraction, purification, and quantification DNA derived as large portion microbial community possible, with special emphasis placed obtaining gram-positive...
The N2O : N2 product ratio of denitrification is negatively correlated with soil pH, but the mechanisms involved are not clear. We compared soils from field experiments where pH had been maintained at different levels (pH 4.0–8.0) by liming (≥20 years), and quantified functional gene pools (nirS, nirK nosZ), their transcription gas kinetics (NO, N2) as induced anoxic incubation without a carbon substrate (glutamate). Denitrification in unamended appeared to be based largely on activation...
The effects of long-term heavy metal deposition on microbial community structure and the level bacterial tolerance were studied along two different gradients in Scandinavian coniferous forest soils. One was near Harjavalta smelter Finland, one at Ronnskar Sweden. Phospholipid fatty acid (PLFA) analysis revealed a gradual change soil communities both pollution gradients, most individual PLFAs changed similarly to sites. relative quantities br18:0, br17:0, i16:0, i16:1 increased with...
Denitrifying prokaryotes use NO(x) as terminal electron acceptors in response to oxygen depletion. The process emits a mixture of NO, N(2)O and N(2), depending on the relative activity enzymes catalysing stepwise reduction NO(3)(-) finally N(2). Cultured denitrifying show characteristic transient accumulation NO(2)(-), NO during transition from oxic anoxic respiration, when tested under standardized conditions, but this character appears unrelated phylogeny. Thus, although community soils...
Summary Denitrifiers differ in how they handle the transition from oxic to anoxic respiration, with consequences for NO and N 2 O emissions. To enable stringent comparisons we defined parameters describe denitrification regulatory phenotype ( DRP ) based on accumulation of − , oxic/anoxic growth transcription functional genes. Eight T hauera strains were divided into two distinct types. Four characterized by a rapid, complete onset RCO all genes no detectable nitrite accumulation. The others...
Accumulating empirical evidence over the last 60 years has shown that reduction of N2O to N2 is impaired by low soil pH, suggesting liming acid soils may reduce emissions. This option not gained much momentum in global change research, however, possibly due limited understanding why pH interferes with reductase. We hypothesized reason denitrifying organisms are unable assemble functional reductase (N2OR) at as be case for model strain Paracoccus denitrificans. tested this experiments...
The effects of heavy-metal-containing sewage sludge on the soil microbial community were studied in two agricultural soils different textures, which had been contaminated separately with three predominantly single metals (Cu, Zn, and Ni) at levels more than 20 years ago. We compared community-based microbiological measurements, namely, phospholipid fatty acid (PLFA) analysis to reveal changes species composition, Biolog system indicate metabolic fingerprints communities, thymidine...
summary The growth of ten species ectomycorrhizal fungi was measured in liquid media containing different organic and inorganic nitrogen sources. All grew well on ammonium. Growth nitrate generally lower, although there considerable variation between isolates the same species. Suillus variegatus, Piloderma croceum, Paxillus involutus, Hebeloma crustuliniforme unidentified pink white often as sources other more variable. Isolates Thelephora terrestris Lactarius rufus varied their ability to...
Denitrification in soil is a major source of atmospheric N(2)O. Soil pH appears to exert strong control on the N(2)O/N(2) product ratio (high ratios at low pH), but reasons for this are not well understood. To explore possible mechanisms involved, we conducted an in-depth investigation regulation denitrification model organism Paracoccus denitrificans during transition anoxia both 7 and when challenged with pHs ranging from 6 7.5. The kinetics gas transformations (O(2), NO, N(2)O, N(2)) were...
Soil bacterial biomass, phospholipid fatty acid pattern, pH tolerance, and growth rate were studied in a forest area Finland that is polluted with alkaline dust from an iron steel works. The pollution raised the of humus layer 4.1 to 6.6. Total numbers total amounts acids did not differ between unpolluted control sites ones. number CFU increased by factor 6.4 compared controls, while rate, measured thymidine incorporation technique, about 1.8-fold sites. A shift pattern indicated species...
A thymidine incorporation technique was used to determine the tolerance of a soil bacterial community Cu, Cd, Zn, Ni, and Pb. An agricultural artificially contaminated in our laboratory with individual metals at three different concentrations, results were compared obtained by using plate count technique. Thymidine found be simple rapid method for measuring tolerance. Data this very reproducible. linear relationship between changes levels techniques ( r = 0.732, P < 0.001). increase metal...
OPINION article Front. Microbiol., 10 February 2016Sec. Terrestrial Microbiology Volume 7 - 2016 | https://doi.org/10.3389/fmicb.2016.00073
The strong greenhouse gas nitrous oxide (N2O) can be emitted from wastewater treatment systems as a byproduct of ammonium oxidation and the last intermediate in stepwise reduction nitrate to N2 by denitrifying organisms. A potential strategy reduce N2O emissions would enhance activity reductase (NOS) microbial community. survey existing literature on denitrification showed that reducing capacity (VmaxN2O→N2) exceeded produce (VmaxNO3→N2O) factor 2–10. This suggests an effective sink for N2O,...
Summary Ammonia oxidising bacteria (AOB) are thought to emit more nitrous oxide (N 2 O) than ammonia archaea (AOA), due their higher N O yield under oxic conditions and denitrification in response oxygen (O ) limitation. We determined the kinetics of growth turnover nitric (NO) at low cell densities Nitrosomonas europaea Nitrosopumilus maritimus (AOA) during gradual depletion TAN (NH 3 + . Half‐saturation constants for were similar those by others, except half‐saturation constant ammonium N....
When oxygen becomes limiting, denitrifying bacteria must prepare for anaerobic respiration by synthesizing the reductases NAR (NO3- → NO2-), NIR (NO2- NO), NOR (2NO N2O), and NOS (N2O N2), either en bloc or sequentially, to avoid entrapment in anoxia without energy. Minimizing metabolic burden of this precaution is a plausible fitness trait, we show that model denitrifier Paracoccus denitrificans achieves all cells, while only minority synthesize NIR. Phenotypic diversification with regards...
Soil pH is a key controller of denitrification. We analysed the metagenomics/transcriptomics and phenomics two soils from long-term liming experiment, SoilN (pH 6.8) un-limed SoilA 3.8). had severely delayed N
All molecular analyses of soil bacterial diversity are based on the extraction a representative fraction cellular DNA. Methods DNA for this purpose divided into two categories: those in which cells lysed within (direct extraction) and first removed from (cell then lysed. The study was to compare method direct with were separated matrix by Nycodenz gradient centrifugation order evaluate effect these different approaches analysis spectrum microbial community. We used polymerase chain reaction...