Differentiation of the Vegetative and Sporogenous Phases of the Actinomycetes: 1. The Lipid Nature of the Outer Wall of the Aerial Mycelium

SUMMARY: The characteristic dry powdery appearance of the aerial mycelium of actinomycetes and the difficulty of wetting the constituent spores appear to be due to lipid substances in their outer walls. These substances are removed by fat solvents, and wetting agents, destroyed by alkali and are probably glyceride in nature. A staining with Sudan IV in ethanol clearly distinguishes the lipid-containing aerial mycelium from the vegetative mycelium.