Glyphosate-degrading behavior of five bacterial strains isolated from stream biofilms.

The present study investigates the individual degrading behavior of bacterial strains isolated from glyphosate-degrading stream biofilms. In this aim, biofilms were subjected to enrichment experiments using glyphosate or its metabolite AMPA (aminomethyl phosphonic acid) as the sole phosphorus source. Five bacterial strains were isolated and taxonomically affiliated to Ensifer sp.

Effects of sulfonamide antibiotics on aquatic microbial community composition and functions.

Knowledge on interactions among microbial communities colonizing various streambed substrata (e.g. cobbles, sediment, leaf-litter etc.

Stimulation or inhibition: Leaf microbial decomposition in streams subjected to complex chemical contamination.

Leaf litter decomposition is a key mechanism in headwater streams, allowing the transfer of nutrients and energy into the entire food web. However, chemical contamination resulting from human activity may exert a high pressure on the process, possibly threatening the structure of heterotrophic microbial communities and their decomposition abilities. In this study, the rates of microbial Alnus glutinosa (Alnus) leaf decay were assessed in six French watersheds displaying different land use (agricultural, urbanized, forested) and over four seasons (spring, summer, autumn, winter).

Biodegradation and toxicity of a maize herbicide mixture: mesotrione, nicosulfuron and S-metolachlor.

The prediction of chemical mixture toxicity is a major concern regarding unintentional mixture of pesticides from agricultural lands treated with various such compounds. We focused our work on a mixture of three herbicides commonly applied on maize crops within a fortnight, namely mesotrione (β-triketone), nicosulfuron (sulfonylurea) and S-metolachlor (chloroacetanilide). The metabolic pathways of mesotrione and nicosulfuron were qualitatively and quantitatively determined with a bacterial strain (Bacillus megaterium Mes11).

Epiplasmins and epiplasm in paramecium: the building of a submembraneous cytoskeleton.

In ciliates, basal bodies and associated appendages are bound to a submembrane cytoskeleton. In Paramecium, this cytoskeleton takes the form of a thin dense layer, the epiplasm, segmented into regular territories, the units where basal bodies are inserted. Epiplasmins, the main component of the epiplasm, constitute a large family of 51 proteins distributed in 5 phylogenetic groups, each characterized by a specific molecular design.

Characterization and evolution of natural aquatic biofilm communities exposed in vitro to herbicides.

River biofilms are assemblies of autotrophic and heterotrophic microorganisms that can be affected by pollutants such as those found in watersheds and wastewater treatment plants. In the laboratory, experimental biofilms were formed from river water, and their overall composition was investigated. Denaturing gradient gel electrophoresis (DGGE) and cytometry were used to assess the richness and diversity of these communities.

Dose-dependent effects of the herbicide mesotrione on soil cyanobacterial communities.

This study aimed to investigate the dose-response effects of an herbicide on soil photosynthetic microbial communities, particularly cyanobacteria, using a microcosm approach. Pure mesotrione (active ingredient), and Callisto (a commercial formulation of this triketone herbicide), were spread at different rates on soil microcosm surfaces. Soil Chlorophyll concentrations were quantified to assess the photosynthetic biomass, and the genetic structure and diversity of the cyanobacterial community were investigated by a group-specific polymerase chain reaction followed by denaturing gradient gel electrophoresis.