RESUMO
Hardy, Paul H., Jr. (The Johns Hopkins University School of Medicine, Baltimore, Md.), and Carole O. Munro. Nutritional requirements of anaerobic spirochetes. I. Demonstration of isobutyrate and bicarbonate as growth factors for a strain of Treponema microdentium. J. Bacteriol. 91:27-32. 1966.-The previously reported ability of a microaerophilic diphtheroid to support the growth of some oral spirochetes resides in the acid-distillable fraction of the culture fluid. This fraction can be replaced by isobutyrate and, to a lesser extent, by 2-methylbutyrate. When media are supplemented with isobutyrate alone, there is a prolonged lag phase before spirochetal growth commences, but when sodium bicarbonate is also added the lag phase is shortened, and both the growth rate and the total yield are increased. Serum, in low concentration, also acts as a growth stimulant, but it is inhibitory when present at higher concentrations.