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A simple in vitro system was developed as a model structure of biofilms and to evaluate their susceptibility to antibiotics. Viable Escherichia coli cells were entrapped in agar gel layers and incubated for 2 days in a minimal salt medium supplemented with glucose. After subsequent culture for 3 weeks under metal ion depletion, the biomass distribution(More)
Viable cells of Escherichia coli were entrapped in agar gel layers to form artificial biofilm-like structures. Killing assays of immobilized organisms by latamoxef and tobramycin were performed under different oxygenation conditions of the culture medium and compared with free-cell experiments. Under moderate aeration, agar-entrapped bacteria displayed(More)
Population dynamics was studied in a 52-l biotrickling filter (BTF) operated for 182 days and used to clean air contaminated with styrene vapors. In the BTF, biomass grew either as free-floating (planktonic) or attached (sessile) microorganisms. PCR-amplified 16S rDNA fragments from planktonic and sessile cells within the bioreactor were analyzed using(More)
Polynucleotide phosphorylase (PNPase), encoded by the pnp gene, is known to degrade mRNA, mediating post-transcriptional regulation and may affect cellular functions. The role of PNPase is pleiotropic. As orthologs of the two major ribonucleases (RNase E and RNase II) of Escherichia coli are missing in the Campylobacter jejuni genome, in the current study(More)
A new Bifidobacterium species is described based on the study of ten Gram-positive strains with fructose-6-phosphate phosphoketolase activity. They are part of a phenotypic group comprising 141 strains isolated from raw milk and raw milk cheeses in French raw milk cheese factories. This group was separated by a numerical analysis based on API 50CH, API 32A(More)
One hundred one strains of Listeria monocytogenes isolated from seafood and cheese industry samples and from patients with listeriosis were assessed using a microtiter plate method for adhesion to polystyrene and stainless steel surfaces. The adhesion rate for these strains ranged from 3.10 to 35.29% with an inoculum of 8 x 10(8) cells per well. A strong(More)
There is considerable interest in the use of psychrotrophic bacteria for food biopreservation and in the understanding of cold adaptation mechanisms. The psychrotrophic biopreservative Lactococcus piscium strain CNCM I-4031 was studied for its growth behavior and proteomic responses after cold shock and during cold acclimation. Growth kinetics highlighted(More)
The green fluorescent protein gene (gfp) was introduced into a p-nitrophenol-metabolizing strain of Moraxella sp. by chromosomal integration. The gfp-marked transformants, designated Moraxella sp. strains G21 and G25, exhibited green fluorescence under UV light. Molecular characterization by PCR and Southern hybridization showed the presence of gfp in both(More)
AIMS To study the accumulation of the bacterial living cells (LC) and dead cells (DC) in a mixed-species biofilm developed in a 3 l biotrickling filter (BTF) challenged with toluene. METHODS AND RESULTS The bacterial LC and DC within the biofilm developed on polypropylene Pall rings in a toluene-degrading BTF were enumerated as fluoro-microscopic counts(More)
AIMS To understand the microbial ecology underlying trichloethene (TCE) degradation in a coupled anaerobic/aerobic single stage (CANOXIS) reactor oxygenated with hydrogen peroxide (H2O2) and in an upflow anaerobic sludge bed (UASB) reactor. METHODS AND RESULTS The molecular study of the microbial population dynamics and a phylogenetic characterization(More)