Effect of repeated applications of copper sulfate on the structure of rhizobium communities

International audienc

Effects of repeated applications of the fungicide "Bordeaux mixture"(copper sulfate) on the diversity of bacterial populations as estimated by PCR-RFLP analysis of 16S rDNA

National audienc

Evaluation of denaturing gradient gel electrophoresis in the detection of 16S rDNA sequence variation in rhizobia and methanotrophs

The ability of denaturing gradient gel electrophoresis (DGGE) technique to resolve 16S rDNA products generated from two different collections of bacteria using universal 16S primers was investigated. Alignments of 16S rDNA sequences of known species of rhizobia and methanotrophs were performed in order to determine the genetic variations within a 200 bp product obtained with PCR primers which amplify the 16S rRNA encoding genes from Eubacteria. Theoretical DNA melting curves were obtained with the Melt87 program and found to correlate with the ability to resolve fragments by DGGE. In the case of the rhizobia, the inability of DGGE analysis to resolve the PCR products from closely related species was in accordance with the low polymorphism observed amongst the sequences in the amplified area. In the case of the methanotrophs, the PCR products were surprisingly difficult to resolve given the high degree of sequence polymorphism of the amplified area in some distantly related species. The difference in sequence divergence within the two groups members allowed therefore to scale the resolution ability of the DGGE technique

Effects of repeated applications of copper sulfate on the diversity of bacterial populations as estimated by ardra analysis

International audienc

Evaluation of denaturing gradient gel electrophoresis in the detection of 16S rDNA sequence variation in rhizobia and methanotrophs

International audienc

A fully consistent and conservative vertically adaptive coordinate system for SLIM 3D v0.4 with an application to the thermocline oscillations of Lake Tanganyika

The discontinuous Galerkin (DG) finite element method is well suited for the modelling, with a relatively small number of elements, of three-dimensional flows exhibiting strong velocity or density gradients. Its performance can be highly enhanced by having recourse to r-adaptivity. Here, a vertical adaptive mesh method is developed for DG finite elements. This method, originally designed for finite difference schemes, is based on the vertical diffusion of the mesh nodes, with the diffusivity controlled by the density jumps at the mesh element interfaces. The mesh vertical movement is determined by means of a conservative arbitrary Lagrangian–Eulerian (ALE) formulation. Though conservativity is naturally achieved, tracer consistency is obtained by a suitable construction of the mesh vertical velocity field, which is defined in such a way that it is fully compatible with the tracer and continuity equations at a discrete level. The vertically adaptive mesh approach is implemented in the three-dimensional version of the geophysical and environmental flow Second-generation Louvain-la-Neuve Ice-ocean Model (SLIM 3D; www.climate.be/slim). Idealised benchmarks, aimed at simulating the oscillations of a sharp thermocline, are dealt with. Then, the relevance of the vertical adaptivity technique is assessed by simulating thermocline oscillations of Lake Tanganyika. The results are compared to measured vertical profiles of temperature, showing similar stratification and outcropping events

Impacts d'applications répétées de sulfate de cuivre sur les activités et la biodiversité microbiennes

National audienc

Impacts d'applications répétées de sulfate de cuivre sur les activités et la biodiversité microbiennes. Application à l'étude des sols viticoles

National audienc