Steroid Requirements of Trichomonads*

Abstract

SYNOPSIS. The steroid requirement of a Trypticase‐requiring strain, SLT, of Trichomonas gallinae on the Shorb‐Lund synthetic basal medium minus ribonucleic acid was fulfilled by cholesterol, 7‐dehydrocholesterol(provitamin D3), cholestanol (dihydrocholesterol), and to a lesser degree, by ergosterol (provitamin D2), β‐sitosterol and zymosterol acetate. Cholestanol was inhibitory at certain concentrations. All steroids were subsequently checked by gas chromatography. Only cholesterol and zymosterol acetate showed one peak, the others containing 2 to 4 peaks. Repurified cholestanol was active and showed no inhibition of growth, but repurified β‐sitosterol was inactive. The following were also inactive: diethylstilbestrol, estrone, dehydroepiandrosterone, progesterone, testosterone, desoxycorticosterone acetate, cortisone acetate, compound A, 5,6‐dihydro‐ergosterol, dihydroergosterol acetate, stigmasterol, sodium taurocholate, cholic acid, methyl desoxycholate, desoxycholic acid and methyl cholate. Precursors in cholesterol synthesis, acetate, mevalonic acid, mevalonic acid plus a liver extract and squalene were inactive in replacing cholesterol, although acetate is required for growth in the presence of cholesterol. Crystalline fat soluble vitamins, carotene, calciferol (vitamin D2), activated 7‐dehydrocholesterol (vitamin D3), menadione (vitamin K3) and tocopheryl acetate (vitamin E acetate) were inactive in replacing cholesterol. Trichomonas species PN from the pig's nose utilized cholesterol, 7‐dehydrocholesterol and the impure β‐sitosterol sample in a modified SL medium with acetate omitted. A reinvestigation of steroid requirements seems to be indicated when a completely synthetic medium and pure steroids are available.

New defined and semi-defined media for cultivation of the flagellate Trichomonas vaginalis

“…Indeed, this review (Shorb, 1964) still summarizes much of what was known of the nutritional requirements of the trichomonads before the presently described work. Relevant earlier work using trichomonads both from poikilotherms and homeotherms indicated a probable requirement for sterols (Mandel & Honigberg, 1957;Lund & Shorb, 1962), nucleic acid precursors (Lee & Pierce, 1960), trace metals (Shorb, 1964) and fatty acids (Shorb & Lund, 1958, 1959. However, no trichomonad appears to have been successfully subcultured repeatedly in a medium free of ill-defined substances such as serum, yeast extract or trypticase.…”

A MEMBRANOUS APPARATUS IN A FLAGELLATE, TRITRICHOMONAS AUGUSTA

“…The involvement of the extensive SR of liver cells in cholesterol synthesis has been firmly established (2). Although it has a well-developed SR, T. augusta cannot synthesize cholesterol, a nutritional requirement for trichomonads (10). Nevertheless, certain species possess enzymes for steroid conversion (14).…”