CONTROL OF FRUITING BODY DIFFERENTIATION IN CHONDROMYCES APICULATUS BY ENVIRONMENTAL FACTORS

Abstract

Chondromyces apiculatus, strain Cm a2, isolated in Minneapolis from decaying wood, was grown as a pure culture on yeast agar for years without ever producing fruiting bodies. When agar blocks with fractions of the swarm edge were punched from the culture plate and transferred to a salt solution containing Ca’ and Mg**, well differentiated fruiting bodies developed. Fruiting body production was found to be under strict control by a number of environmental factors: 1)The temperature must not exceed 30°C, although good arowth occurs still several degrees higher. 2) The surface of the agar block must not be submerged under the surface of the salt solution. 3) The cultures must be illuminated during induction. The quality of the light has no influence, at least in the visible range, even red light being fully effective. In red light the fruiting bodies remain pale,however, because carotenoid synthesis is at dark level under this condition. Light has to be present during the whole developmental process, as cell accumulation as well as fruiting body morphogenesis depend on licht. 4) The relative proportion of the Ca** and Mg** concentrations has a striking effect on the shape of the developing fruiting bodies. 5) Addition of nutrients to the salt solution, e.g. of a little Casitone solution, suppresses fruiting body formation completely; neither are fruiting bodies obtained by induction in deionized water. Finally, 6) if the initial population density is too low, no fruiting bodies can be formed even if all other conditions are right. The induction system worked out for Cm a2, seems to be specific for this one strain: no fruiting bodies were obtained under identical conditions with a number of other strains of Cm. apiculatus, nor with Cm. pediculatus, let alone myxobacteria of other genera.