Vitamin Deficiency as One Explanation for Inhibition of Protozoan Growth by Conditioned Medium

作者：R. P. Hall · 发表于：Experimental Biology and Medicine · 年份：1941 · DOI：10.3181/00379727-47-13120 · 被引用次数：7 · 研究领域：Reproductive biology and impacts on aquatic species、Plant tissue culture and regeneration、Pesticide and Herbicide Environmental Studies

Accelerative effects of biologically conditioned casein-peptone medium, when added to fresh medium in proportions of 1-5 parts in 10, have been reported previously for Colpidium campylum. Subsequently, it has been found that an increase in the proportion of conditioned medium induces inhibitory effects on the growth of Colpidium campylum and Glaucoma piriformis. Observations on the latter are presented below. Series I and II. A culture filtrate was prepared from 96-day flask-cultures of G. piriformis in casein-peptone (Difco “tryptone”) medium containing KH2PO4 (1.0 g per 1). The cultures were filtered through paper (Whatman No. 12), as previously described by Hall and Loefer, and the filtrate was divided into two portions. One portion (Series I) served as the control medium. To the other (Series II), the following growth-factors were added: Merck's thiamine hydrochloride (1 × 10-6 g per cc), Merck's riboflavin (1 × 10-7 g per cc), and S. M. A. Corporation's nicotinic acid amide (1 × 10-7 g per cc). Each medium was tubed in 10 cc amounts and sterilized in the autoclave at 122° C for 20 minutes. All tubes received 0.5 cc inocula from a 3-day culture of G. piriformis in the basic medium. In both series, the initial pH was 6.9; initial count, 4,000 ciliates per cc. All cultures were incubated in darkness at 24°C, and counts were made at the indicated intervals (Fig, 1, A). Series III and IV. The procedure was the same as above, except that 109-day flask-cultures were used as the...