[The bactericidal activity of lectins from nitrogen-fixing bacilli]. / Bakteritsidnye svoistva lektinov azotfiksiruiushchikh batsill.

Lectins I and II isolated from the nitrogen-fixing soil bacterium Paenibacillus polymyxa 1460 were found to be able to suppress the growth of Rhizobium leguminosarum 252 and Bacillus subtilis 36 at nearly all the concentrations tested (from 1 to 10 micrograms/ml). Lectin I was also inhibitory to Azospirillum brasilense 245 and Erwinia carotovora subsp. citrulis 603, while lectin II exerted bactericidal activity against Xanthomonas campestris B-610 and B-611 and A. brasilense 245. The bacillar lectins incubated with Rhizobium and Azospirillum cells caused leakage of low-molecular-weight substances from the cells, presumably resulting from impairment of the membrane barrier function. We believe that one of the possible mechanisms of the bacterial growth inhibition by lectins is mediated by the lectin-specific receptors occurring on the bacterial membrane, whose interaction with the lectin molecules induces conformational alterations in the membrane and concurrent malfunction of the metabolism of bacterial cells.

[Biological role of lectins from Bacillus polymyxa during interaction with surface carbohydrates of wheat roots ]. / Izuchenie biologicheskoi roli lektinov Bacillus polymyxa pri vzaimodeistvii s uglevodami fraktsii ékzokomponentov kornei pshenitsy.

The data obtained demonstrate the capacity of lectins LI and LII from the soil nitrogen-fixing bacteria Bacillus polymyxa 1460 to change their proteolytic activity after interaction with surface carbohydrates of wheat seedling roots.

[Role of the agglutinating proteins of bacilli and rhizobia in bacterial interaction]. / Rol' aggliutiniruiushchikh belkov batsill i rizobii v mezhbakterial'nykh vzaimodeistviiakh.

The surface agglutinating proteins of the soil nitrogen-fixing bacteria Bacillus polymyxa 1460 and Rhizobium leguminosarum 252 were found to be able to interact with the polysaccharide complexes of certain azospirilla and rhizobia. Such interactions are most likely involved in the formation of nitrogen-fixing plant-bacterial associations in the rhizosphere.

[Proteolytic activity of lectins from the nitrogen-fixing bacterium Bacillus polymyxa]. / Proteoliticheskaia aktivnost' lektinov azotfiksiruiushchikh bakterii Bacillus polymyxa.

Two lectins (LI and LII) stripped from the surface of Bacillus polymyxa 1460 cells were found to possess proteolytic activity, which was associated with their hemagglutinating activity. The inhibition of the hemagglutinating activity of lectins by specific carbohydrate haptens changed their enzyme activities. The inhibition of hemagglutinating activity by glucuronic acid or fructose 1,6-diphosphate decreased the proteolytic activities of both lectins, whereas the blocking of this activity with D-glucosamine or D-galactosamine increased the proteolytic activity of LII. The molecules of the B. polymyxa lectins are suggested to contain two active centers responsible for hemagglutinating and proteolytic activities.