Sashchuk O. Structural organization and influence of Bacillus subtilis lectins on cell processes

PhD work was dedicated to study of structural organization features of Bacillus subtilis IMV B-7014 extracellular sialic acid-specific lectin and investigation of action mechanisms on cell processes by saprophytic bacterium B.subtilis lectins. It has been determined for the first time that extracellular lectin of saprophytic strain B. subtilis IMV B-7014 as lectins of plant and animal origin constitutes complex of isoforms that are notable for physical-chemical and biological characteristics: movement direction in electric field, localization according to pI, electroforetic mobility, affinity with erythrocytes of different animal species, level of hemagglutination activity and carbohydrate specificity. Extracellular and cell surface lectin syntheses depend on presence of certain carbohydrate in nutrient medium by natural and mutant strains B.subtilis. Strain peculiarities consist in production of these form lectins become apparent to a great extent with use of galactose as carbon source. Lectin activity can increase to 64 times or be lost completely. Mutations in reparation/recombination system reduce to intensification of these effects. For the first time it has been shown B. subtilis IMV B-7014 extracellular lectin makes an inhibiting action on mitomycin C bacteriostatic impact, i.e. for the lectin the most sensitive target is replication process. Modulatory effect of plant lectin on cytostatic action phenazine and its derivations in B. subtilis system is mediated by own lectins of bacteria. In transcription in vitro with use of DNA-dependent RNA-polymerase of bacteriophage T7 has been determined different directional impact of B. subtilis IMV B-7014 extracellular lectin isoforms on yield of RNA-product, i.e. DNA-dependent RNA-synthesis is likely one of cell targets of bacillary lectins' action.