Search

This article presents an analysis of the microbial community growing on a stainless steel plate. A sample from this plate has been tested for the rpoC gene. Dominant biofilm species (clones) were identified with the help of molecular cloning and nucleotide sequencing of a 16S rRNA gene fragment. The activities of planktonic microorganisms and biofilm microorganisms attached to the plate were compared. Seven of nineteen sequences (37%) were found to belong to the Sphingobacteria group. Analysis of 16S rRNA gene sequences cloned from natural biofilms sampled from Lake Baikal showed a great variety of microorganisms in the biofilm. The following taxonomic groups were revealed among them: sphingobacteria, α-proteobacteria, cyanobacteria, verrucomicrobia, bacilli, γ-proteobacteria, flavobacteria, and β-proteobacteria. This kind of analysis was done in Lake Baikal for the first time.

Development of benthic communities on rocks from the interdisciplinary test site near Cape Berezovyi (southern Baikal) is analyzed. Rock plates were placed on the bottom in the shallow-water zone of Baikal for six months, and a community consisting of microorganisms, microphytobenthos, and meiobenthos developed on them. The development and activity of hydrobionts depended on the chemical composition and structure of the rock. Marble and granite plates were populated by them more selectively than amphibolite plates. It is supposed that the biota plays an important role in destruction of rocks in the shallow-water zone of Baikal.

Experimental production, characterization and evaluation of the role of cholera vibrio biofilm.33 strains of Vibrio cholerae eltor O1 and V. cholerae O139 of various epidemic significance and origin were studied in a series of experiments by bacteriologic, microscopic (light-optic, luminescent, scanning electron microscopy), molecular genetics, spectrophotometric and statistical methods.Formation of a biofilm involving inter-cellular bonds, pili and extracellular material and variability of the microorganism (RO-phenotype and transition into uncultivable forms) was shown at various temperature and substrate conditions. A more pronounced ability to form biofilms was detected for strains isolated from environmental samples compared with isolated from clinical material regardless of their epidemic significance. Toxigenic strains of eltor biovar (from surface reservoirs during cholera outbreaks) have demonstrated the highest parameters of optical density compared with toxigenic clinical isolates and non-toxigenic O1 and O139 serogroup cultures. The presence of mbaA1 and mbaA2, vpsR, toxR, hapA genes is common for strains that form a biofilm.The data obtained confirm the role of biofilm in reservation of cholera vibrio strains of various epidemic significance in saprophytic phase of microorganism existence.