Nutritional Requirements of C. diphtheriae and L. casei

Abstract

THE investigations of Lythgoe, Macrae, Todd and others¹ upon rat growth-factors present in liver extracts, and those of Evans, Handley and Happold² on the nutrition of C. diphtheriæ (types intermediate and gravis), established the identity of a common growth-factor in these extracts with pantothenic acid. The former investigators also established the presence of another rat growth-factor (factor B) in the amyl alcohol-insoluble fraction of acidified liver concentrates. Active preparations of this factor were found to promote the growth of certain intermediate types of C. diphtheriæ, and in 1940 Happold, Lythgoe and Todd commenced a joint investigation with the object of elucidating its nature. The factor could not be extracted by amyl alcohol from aqueous acid solution or by butanol from alkaline solution. At pH 1 it was not adsorbed on fullers earth but was readily adsorbed on charcoal (Norite), from which it could be eluted with acetone-ammonia-water. Treatment with 20 per cent hydrochloric or sulphuric acids at 100° for two hours caused little diminution in activity, but similar treatment at pH 11 (sodium hydroxide) caused almost complete inactivation. Complete loss of activity was also caused by acetylation, methylation or treatment in the cold with nitrous acid. The growth-factor was not precipitated by phosphotungstic acid, and attempts to purify further via the lead salt were inconclusive, much activity being lost in the process.