No abstract

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 22.0, while autolysis was induced to values of 2.81-56.7% in four naturally nonautolyzing strains. When given to mice per os, all the food-protein hydrolysates enhanced the phagocytosing capacity of peritoneal macrophages, with the enhancement index (K(I)) ranging from 1.02 to 1.41. A direct correlation between K(A) and K(I) was observed. We make the presumption that K(I) is a function of K(A).

The effects of treatment/prophylaxis of newborn calf colibacillosis with tryptic casein hydrolysate (TCH), recently shown to be a novel type of antimicrobial acting through stimulation of the microbial autolytic system, versus an authorized veterinary drug, Fermosorb, were evaluated. Both products showed similar high therapeutic and prophylactic efficacies, but hematological indices and daily weight gain of cured/protected animals were better with TCH. The differences in hemoglobin and hematocrit levels, total protein, gamma-globulin and sulfhydryl group quantities, bactericidal and lysozyme activities as well as daily weight gain at the end of treatment/prophylaxis were statistically significant (P<0.05-0.000005). Statistically significant differences (P<0.05-0.0005) in favor of TCH were also observed when bactericidal activity, total protein quantity of serum as well as daily weight gain of the animals were compared on the 90th day after birth. We conclude that TCH acts not only as an antimicrobial, but also as an immunostimulant (and growth promoter). The immunostimulatory activity of TCH most probably derives from a synergistic action of bioactive peptides encrypted in the preparation itself and the cell wall fragments resulting from microbial autolysis induction.

No abstract

As Clostridium perfringens hyaluronidase has cell‐bound enzyme features, an enzymatic approach has been designed to facilitate the release of hyaluronidase into culture through increasing the clostridial cell wall permeability. As a result of the application of lytic peptidase from Actinomyces rutgersensis,β‐N‐acetylglucosaminidase and β‐N‐acetylmuramidase (both from Bacillus subtilis) commercially available preparations at the end of the producer's exponential growth phase, a 5·3‐, 4·8‐ and 4·0‐fold acceleration, respectively (but no enhancement), of hyaluronidase production in the course of batch cultivation of Cl. perfringens has been achieved. This also resulted in an approximately 10‐fold reduction in undesirable side lecithinase activity irrespective of the bacteriolytic enzyme preparation used.