Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify.

Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB).

Diversity of Vibrio spp. isolated at ambient environmental temperature in the Eastern English Channel as determined by pyrH sequencing.

Aims: To describe the diversity of the culturable mesophilic and potentially pathogenic vibrios isolated at 22 and 37°C on TCBS medium, in September 2009 from seawater and surface sediments.

Methods And Results: q-PCR assays previously selected for the identification of bacterial strains isolated at 37°C were used in combination with the partial sequencing of two housekeeping genes, pyrH and toxR, to identify 315 strains isolated at 22°C. The great majority of the 37°C strains was identified by q-PCR assays, (five of the six species) with the predominance of Vibrio alginolyticus (85·9%) and V.

Real-time PCR optimization to identify environmental Vibrio spp. strains.

Aims: To identify Vibrio vulnificus, Vibrio cholerae and Vibrio alginolyticus using standardized DNA extraction method and real-time PCR assays, among a large number of bacterial strains isolated from marine environment.

Methods And Results: Methods for DNA extraction and real-time PCR were standardized to identify a large number of Vibrio spp. strains isolated through regular collection campaigns of environmental samples.

Total and viable Legionella pneumophila cells in hot and natural waters as measured by immunofluorescence-based assays and solid-phase cytometry.

A new method was developed for the rapid and sensitive detection of viable Legionella pneumophila. The method combines specific immunofluorescence (IF) staining using monoclonal antibodies with a bacterial viability marker (ChemChrome V6 cellular esterase activity marker) by means of solid-phase cytometry (SPC). IF methods were applied to the detection and enumeration of both the total and viable L.

Usefulness of real-time PCR as a complementary tool to the monitoring of Legionella spp. and Legionella pneumophila by culture in industrial cooling systems.

Aims: This study was designed to evaluate the usefulness of quantification by real-time PCR as a management tool to monitor concentrations of Legionella spp. and Legionella pneumophila in industrial cooling systems and its ability to anticipate culture trends by the French standard method (AFNOR T90-431).

Methods And Results: Quantifications of Legionella bacteria were achieved by both methods on samples from nine cooling systems with different water qualities.