[Effect of cultivation conditions of Bacillus subtilis IMV B-7023 on surface properties of cells].

It has been established that the cells of Bacillus subtilis IMV B-7023 grown on the medium where peptone or calcium glycerophosphate served as the only source of carbon and energy have similar acid type of the surface and are characterized by a high negative charge even at low values of pH of the dispersion medium. This may be determined by the presence of phosphate groups, teichoic acids being their carriers in Gram-positive bacteria. Glucose addition to peptone or glycerophosphate leads to the change of the bacteria surface type, i.e., at low values of pH the cells have total positive charge, that allows to suppose availability of protein nature components in the surface layers of the cell wall. Bacteria grown in these conditions are also characterized by the higher degree of adhesion to inert carrier (glass).

[Chemotaxis of Bradyrhizobium japonicum to various organic compounds]. / Khemotaksis Bradyrhizobium japonicum k razlichnym organicheskim soedineniiam.

The investigation of the chemotactic response of Bradyrhizobium japonicum to amino acids, carbohydrates, multiatomic alcohols, organic acids, and soybean extracts showed that the extracts of some soybean varieties (Chernoburaya and Beskluben'kovaya) contain repellents. This indicates that the soybeans of host plants contain effectors that may play a role at the early stages of their interaction with nodule bacteria.

[Effect of certain environmental factors on Bradyrhizobium japonicum]. / Vliianie nekotorykh faktorov vneshnei sredy na khemotaksis Bradyrhizobium japonicum.

Dependence of motility and chemotaxis was studied in two strains of Bradyrhizobium japonicum upon several environmental factors. In both strains, chemotaxis was found to increase with an increasing concentration of the attractant (glucose) to 5.6 x 10(-2) M. Both motility and chemotaxis reached their maximum in the two- to three-day cultures at neutral pH. The maximum motility of these bacteria occurred at 40 degrees C. The maximum values of chemotaxis in these microorganisms were, however, observed at 20-25 degrees C. Chemotaxis in acidic or alkaline media and at low temperatures was found to be markedly weaker. Nonoptimal values of these parameters in soil may be a limiting factor for the interaction of the given bacteria with soybean roots.