The nfs locus is necessary for formation of viable starvation-induced spores. A. Starvation induced developmental phenotype of the wild type (DK1622) and Δ(nfsA-H) (PH1200) strains. 4 × 107 cells were spotted onto nutrient limited CF agar plates, incubated at 32°C, and development was recorded at the indicated times. By 24 hours development cells aggregate into mounds (fruiting bodies) of approximately 105 cells. Fruiting bodies are displayed at higher magnification at 72 hours to illustrate that the Δ(nfsA-H) fruiting bodies fail to darken. B. Heat and sonication resistant spores (wild type; DK1622) and entities [Δ(nfsA-H); PH1200] isolated after 120 hours of development from A and examined by phase contrast microscopy.