Observations Concerning the Growth and Metabolic Activities of Myxococci in a Simple Protein-free Liquid Medium

Publisher Website
Google Scholar
Abstract
Studies of the growth and metabolic activities of myxococci were carried out using the following organisms: Myxococcus virescens, strains A and G; M. flavus; Staphylococcus aureus; Escherichia coli; and Pseudomonas fluorescens. Fruiting cultures of myxococci were maintained on sucrose Czapek agar slants. The simplest liquid medium which would support the growth contained total acid hydrolyzate of casein as the real nutrient. Arginine, asparagine, histidine, lysine, and Na glutamate were tolerated when added to the basal medium, but alanine, cysteine hydrochloride, and glycine were inhibitory if present in sufficient cones. The myxococci developed a widespread coherent submerged film of bacteria which depended upon the depth of the liquid and the amt. of submerged glass surface (not vertical). The antibactericidal substance produced was not a stable product of metabolism. Better production was obtained when a greater proportion of casein hydrolyzate and a greater area of submerged glass per unit volume of medium were used. The antibactericidal activity was not due to an enzyme. The substance was more stable to heat than the gelatinase. A crude solid product of the antibiotic was prepared which was not inhibitory to Gram-negative bacteria. Gelatinase was produced in this medium. It was heat labile and at pH 7-8 was destroyed by heating the metabolic solution for 10 min. at 60[degree]C. The enzyme was lytic for killed Gram-negative bacteria but not for viable bacteria. The Ca ion probably played no part in the production of the enzyme.