The growth requirements of Clostridium perfringens (welchii) BP6K.

The objectives of the investigation of the nutrition of Clostridiu,m perfringens were twofold. In the first place, the development of a chemically defined medium was prerequisite for the understanding of the factors and conditions favorable to production of t#oxins or exoenzymes. Secondly, it became evident early in the investigation that the organism presented exceptional advantages as a means of assay for amino acids and vitamins. The fact that very dense growth is obtained in 16 hours at 45” in the presence of a reducing agent and the fact that thirteen amino acids and four vitamins are absolute requirements of the organism pointed to the probable merits of the bacterium for their assay. The early experiments in this laboratory on the growth requiremenbs of Clostridium prrfringens demonstrated that the organism would grow in a medium consisting of vitamin-free casein hydrolysate, tryptophan, cystine, glucose, vitamins (biotin, calcium d-pantothenate, riboflavin), uracil, adenine, inorganic salts, and an extract of liver. Later, the organism was grown successfully on a medium which had the same composition as the one above except that chemically pure amino acids were substituted for the casein hydrolysate and pyridoxamine (or pyridoxal) for the extract of liver. The chemically defined medium t’o be described for Clostridium perfringens BPGK consists of nineteen known amino acids, uracil, adenine, glucose, vitamins (biotin, calcium d-pantothenate, riboflavin, pyridoxamine), and salts. This medium supports rapid and luxuriant growth of the organism from a small inoculum. The growth obtained is equal to that produced on a medium prepared from enzymatic digests or hydrolysates of tissues or proteins supplemented with essential requirements. Under t,he conditions of the experiments there is no formation of CT toxin (lecithinase) or any of the other known toxins or exoenzymes (hyaluronidase, 0 toxin, gelatinase) in this medium. However, this organism does not lose its ability t,o form t,oxins when grown under conditions suitable for