[Activity and expression of laccase, tyrosinase, glucanase, and chitinase genes during morphogenesis of Lentinus edodes].

Activation of expression of the lcc4 and tir genes encoding laccase and tyrosinase was observed during transition of a xylotrophic basidiomycete Lentinus edodes from the vegetative to the generative growth stages. This was especially pronounced in the brown mycelial mat (the stage preceding formation of the fruiting bodies). Development of this structure was shown to be associated with a sharp increase of laccase and tyrosinase activities, as well as with rearrangements in the phenol oxidase complex. Formation of the tissues with thickened cell walls was associated with enhanced expression of the chi and exg1 genes encoding chitinase and glucanase, respectively. Exogenous treatment of the vegetative mycelium with laccase preparation from the brown mycelial mat promoted formation of this morphological structure. Activation of the lcc4, tir, chi, and exg1 genes may be used as a marker of readiness to fruition in xylotrophic fungi.

[The effect of topology of quorum sensing-related genes in Pectobacterium atrosepticumon their expression].

In prokaryotic genomes, the neighboring genes are often located on the complementary DNA strands and adjoin each other by their 5'- or 3'-ends or even overlap by their open reading frames. It was suggested that such gene topology hasfunctional purpose providing the regulation of their expression. For those genes that overlap by their coding 3'-termini this assumption has not been confirmed experimentally. In a broad group of bacteria that belong to proteobacteria such a convergent gene arrangement is typical for functionally connected quorum sensing-related genes "P" and "R" that encode synthases of N-acyl homoserine lactones and their sensors, respectively. In the present study on the example of overlapping quorum sensing-related genes of plant pathogenic bacterium Pectobacterium atrosepticum SCRI1043--expI and expR it was shown that the topology of these genes determines the regula- tion of their expression.

[Identification and characterization of non-cultivated forms of enterobacteria Erwinia carotovora in continuously incubated cultures].

AIM: To determine overall number as well as number of viable cells in continuously incubated cultures of E. carotovora by methods of confocal microscopy and quantitative PCR-analysis. MATERIALS AND METHODS: Strain E. carotovora atroseptica SCRI1043 was grown on LB medium to density 2x10(9) CFU/ml. Cells were aggregated by centrifugation and transferred on fresh LB medium, containing alkyloxybenzol, or on the AB medium, which was deficient on phosphorus and carbon. BacLight LIVE/ DEAD kit in combination with confocal laser microscopy as well as quantitative PCR were used for the determination of the number of viable cells. RESULTS: Total number and number of viable cells in cultures on AB medium was high (10() - 10(9) and 10(7) - 10(8) cells/ml respectively) up to 3 - 5 months of cultivation. Though, number of cultivated cells significantly decreased in all variants of the experiment. Number of viable cells in such cultures was several orders greater than genomic copies detected by PCR. Efficacy of DNA amplification increased after dialysis and deproteinization of samples. CONCLUSION: Loss of cultivation ability when number of viable bacteria is high points to possible switch of E. carotovora cells in non-cultivated state under unfavourable conditions. We assume that it is accompanied by formation of low-molecular components and DNA-bound proteins in cells, which inhibit PCR.

[Adaptive reactions of mycoplasmas in vitro: "viable but unculturable forms" and nanocells of Acholeplasma laidlawii].

The adaptation of Acholeplasma laidlawii to conditions unfavorable for growth has been found to be accompanied by cell transformation into special morphological structures known as ultramicroforms (nanocells). The ratio of the cells of the two morphological types in the population depended on the growth conditions. Nanocells retained viability for a long time under conditions unfavorable for growth and showed resistance to stressors. Reduction in the cell size occurred due to unequal division, which involved the loss of cytoplasmic material. A. laidlawii ultramicroforms (nanocells) were able to restore proliferative activity and to revert to their initial vegetative form; they measured less than 0.2 microm and are the smallest cells known at present. Nanocells formed in vitro under exposure to abiogenic stressors may correspond to the A. laidlawii minibodies observed in infected plants upon exposure to biogenic stressors. The transformation of A. laidlawii cells into ultramicroforms was accompanied by condensation of the nucleoid, a change in the polypeptide spectrum, and a change in the availability of rRNA operons for in vitro amplification. All these changes are indicative of reorganization of the genetic and metabolic systems of mycoplasmas.

[The activity of a specialized city medical-and-social center for schoolchildren]. / O deiatel'nosti spetsializirovannogo gorodskogo mediko-sotsial'nogo tsentra dlia shkol'nikov.

Described in the paper is a concept of an alternative educational facility (City center for medical, psychological and social follow-up, diagnosis and consultation of schoolchildren in Yaroslavl) popularizing the healthy mode of life among pupils of general schools. The center's experts developed and tested comprehensive approaches to teaching the motivation and skills of the healthy mode of life through the comprehensive training of pupils, teachers and parents.