Serologically Reactive Polysaccharides Produced through T H E Action of Bacterial Enzymes* I. Dextran of Leuconostoc Mesenteroides ]~ro~ Sucrose

A preliminary paper (1) reported that a serologically reactive polysaccharide of dextran nature is produced from sucrose through the action of an enzyme or some similar heat-labile agent contained in sterile filtered extracts of Leuconostoc mesenteroides. The object of the present paper is to describe the preparation of the sterile extracts and to compare the chemical and serological properties of the dextran formed by the bacteria-free extracts with those of the dextran formed in cultures of the living bacteria. Previous workers have reported the production of gum-like material from sucrose by sterile filtrates derived from various species of spore-forming bacilli. In 1910 Beijerinck (2) described the formation of "slime" on sucrose agar by filtered preparations of Bacillus mesentericus; he considered the active principle to be a "synthetically active enzyme" which he termed viscosaccharase. Harrison, Tarr, and Hibbert (3) reported that a sterile filtrate of similar bacilli formed from sucrose an alcohol-precipitable material which gave opalescent solutions. Also, it is possible that the production of bacteria-free "colonies" on sucrose agar plates by filtrates of sucrose broth cultures of Bacillus fluorescens which has been reported by Dienes (4) and others represents another manifestation of the same phenomenon. However, in none of the earlier studies were the products identified chemically or tested serologically, whereas in the present study the product is proved to be an immunologically reactive polysaccharide similar in both chemical and serological properties to the product formed in cultures of the living bacteria.