[AlkB homologues in thermophilic bacteria of the genus Geobacillus].

Screening of alkane hydroxylase genes (alkB) was performed in the thermophilic aerobic bacteria of the genus Geobacillus. Total DNA was extracted from the biomass of 11 strains grown on the mixture of saturated C10-C20 hydrocarbons, PCR amplification of fragments of alkB genes was performed with degenerate oligonucleotide primers, PCR products were cloned and sequenced. For the first time in the genome of thermophilic bacteria the presence of a set of alkB gene homologues was revealed. The strains each contain three to six homologues among which only two are universal for all of the strains. Comparative phylogenetic analysis of the nucleotide sequences and the inferred amino acid sequences showed close relatedness of six of the revealed variants of geobacilli sequences to the alkB4, alkB3, and alkB2 genes that had previously been revealed by other authors in Rhodococcus erythropolis strains NRRL B-16531 and Q15. The rest two variants of alkB sequences were unique. Analysis of the GC composition of all the Geobacillus alkB homologues revealed closer proximity to the rhodococcal chromosomal DNA than to the chromosomal DNA of geobacilli. This may be an indication of the introduction of the alkB genes into the Geobacillus genome by interspecies horizontal transfer; and rhodococci or other representatives of the Actinobacteria phylum were probably the donors of these genes. Analysis of the codon usage in fragments of alkB genes confirms the suggestion that the pool of these genes is common to the majority of Gram-positive and certain Gram-negative bacteria. Formation of a set of several alkB homologues in a genome of a particular microorganism may result from free gene exchange within this pool.

[Effect of culture conditions on growth and adhesion of Bacillus licheniformis]. / Rost and adgeziia Bacillus licheniformis v zavisimosti ot uslovii kul'tivirovaniia.

Adhesion to glass of actively growing cells of the thermophilic Bacillus licheniformis, isolated from the Medyaginskaya test borehole (Yaroslavl' oblast), was studied. The reversible adhesion (RA) manifests itself in a decline of cell density (short of cell lysis) in the liquid culture over the first 20-40 min of growth followed by normal exponential growth. The RA is minimal under favorable growth conditions but increases when cells are transferred to a new medium, especially one with a pH, temperature, salinity, or concentration of Ca2+ ions nonoptimal for the given species. Under unfavorable growth conditions, the adhesion becomes irreversible. The obtained data suggest that RA represents an adaptation mechanism important for population survival.

[Medical and psychophysiological aspects in the professional orientation of young people]. / Meditsinskie i psikhofiziologicheskie aspekty professionalnoi orientatsii molodëzhi.

The paper deals with the scientific prerequisites for a physiomedical professional consultation as an important prophylactic measure to promote the adolescents' health during vocational training and work. Great emphasis is laid on a comparatively new aspect of professional orientation--physiophychological professional consultation whose goal is to establish their professional fitness due to individual physiological and psychophysiological features of the body and due to the level of development of professionally significant functions and qualities. The paper also gives the data on the basic regularities of ontogenetic development of the leading professionally significant functions and qualities in schoolchildren aged 12-15 years. In addition , it proposes new approaches to making a professiogramme for physiomedical professional orientation and to developing a nomenclature of professions.