Food-protein enzymatic hydrolysates possess both antimicrobial and immunostimulatory activities: a "cause and effect" theory of bifunctionality.

The antimicrobial activity (the ability to activate the microbial autolytic system) and immunostimulatory activity (the ability to improve the phagocytic cell functioning) of 20 food-protein hydrolysates [five food proteins (casein, alpha-lactalbumin, beta-lactoglobulin, ovalbumin and serum albumin) hydrolyzed with four gastrointestinal proteinases (trypsin, alpha-chymotrypsin, pepsin and pancreatin)] were examined. All the food-protein hydrolysates acted antimicrobially in vitro towards all 24 microbial strains tested: autolysis of 20 naturally autolyzing strains was activated, with the autolysis activation index (K(A)) ranging from 1.04 to 22.

Stimulation of microbial autolytic system by tryptic casein hydrolysate.

Antimicrobial activity of a tryptic casein hydrolysate (TCH), its mode of antimicrobial action and its efficacy in treatment using a newborn calf colibacillosis model are described. The antimicrobial activity of TCH activated the autolytic system of the microbial cell and was expressed mathematically as the autolysis activation index. TCH stimulated the autolytic enzyme system of the 19 bacterial and five fungal strains tested.

[Antibacterial spectrum of lisosubtilin G10X].

Data on the antibacterial spectrum of lysosubtilin G10X, a preparation of lytic enzymes from Bacillus subtilis SK-52 are presented. Lysosubtilin was active against grampositive and gramnegative pathogenic bacteria. When it was used as a substrate of live lyophilized microbial cells the highest lysis levels were observed in B.

[Lysosubtilin G10x--a new antimicrobial agent for treatment and prophylaxis. Physico-chemical properties].

Lysosubtilin G10x, a lytic enzyme from Bacillus subtilis SK-52 was studied with respect to its physico-chemical properties such as effect of optimal conditions and stability. The maximum activity of the enzyme was observed in phosphate buffer at a concentration of the buffer mixture equal to 0.004 M, pH 7.

[Composition of the regulators of bacterial autolysis].

This work was aimed at studying the composition of agents regulating bacterial autolysis and isolated from the lysate of Bacillus subtilis 402, B. subtilis R2 and Micrococcus lysodeikticus biomass by extraction with 5% TCA followed by precipitation from the extract with 5 volumes of isopropanol. Fractions activating bacterial autolysis and fractions inhibiting it were found in all of the preparations after separation on Acrylex P-60.