In vitro and in vivo Properties of Culture Filtrates of Bacillus subtilis with High Gelatinase Activity

Abstract

SUMMARY : Concentrated culture filtrates from Bacillus subtilis, with high gelatinase activity, disintegrated hide powder although unable to attack native collagen ; they also haemolysed the red blood cells of a number of species. The concentrated filtrates were dermonecrotic in rabbits and lethal on intravenous injection into mice. There was no conclusive evidence that the factors responsible for any of these effects were antigenic. Although each of the in vitro and in vivo activities was destroyed by heat, the haemolytic activity was more resistant than the others. Fresh normal sera from many species inhibited each of the three properties shown in vitro. Tests with gelatinase showed that inhibition occurred rapidly and in multiple proportions. The inhibitory action was diminished by heat and storage and was distinct from the antitryptic property of serum. It is well known that many species of the genus Bacillus have the property of liquefying gelatin, and Bertiau (1914) originally showed that the enzyme involved in this reaction was present in culture filtrates separated from the bacilli. The activities of the enzyme, apart from its ability to liquefy gelatin, have not been extensively studied, and little is known of its action on other substrates. It was therefore considered desirable, especially in view of the interesting observations made during the last few years on the proteolytic enzymes of the related genus Clostridium, to investigate the activities of the gelatinase of certain species of Bacillus. The initial work reported here was made with culture filtrates of B. subtilis.