THE EFFECTS OF BACTERIA ON THE GROWTH AND REPRODUCTION OF OEDOGONIUM CARDIACUM1

Isolates of male and female Oedogonium cardiacum for which defined media had been established were subsequently found to be contaminated with a species of Corynebacterium which failed to grow in the nutrient broth used, to test for contamination. After the cultures were rendered, axenic through treatment with, penicillin G, they failed to develop oogonia or sperm except occasionally at a very low level. The addition of small amounts of the bacterium increased the development of the reproductive structures; however a much more striking increase was obtained by constantly infecting the algal cultures with Pseudomonas putida. Neither of the bacteria increased growth as measured by dry weight; however the P. putida resulted, in the growth of very long filaments in contrast to the short filaments characteristic of both the axenic cultures and those infected with Corynebacterium sp.