Spore germination and swarm cell morphogenesis in the acellular slime mold Fuligo septica

This report describes conditions under which spores of the acellular slime mold Fuligo septica underwent a very rapid, synchronous and complete (100%) germination followed by morphogenesis of motile, flagellated swarm cells from the released protoplasts. This developmental sequence was initiated immediately upon wetting the spores with a surfactant and was completed within 40–50 min in the absence of any exogenous nutrient other than sodium phosphate buffer. Oxygen was required for germination. The rate and percentage of germination diminished with increasing spore concentration suggesting the existence of an autoinhibitor. The morphological sequence of events in the differentiation process was examined by scanning electron microscopy.     

Revision of the Genus Protostelium (Eumycetozoa) I: The Protostelium mycophaga Group and the P. irregularis Group

ABSTRACT The most commonly encountered protostelids are nominal members of the genus Protostelium Olive & Stoianovitch. These are Protostelium mycophaga Olive & Stoianovitch and P. irregularis Olive & Stoianovitch. Both species share the common features of long-stalked fruiting bodies with single, uninucleate, deciduous spores and trophic states that consist solely of uninucleate amoebae, but they are quite different with respect to their detailed structure at both the light and electron microscopic levels. Based on this evidence, it seems unlikely that the species are congeneric, and it is proposed that P. irregularis be assigned to Soliformovum n. g. Examination of other species of Protostelium indicates that P. nocturnum Spiegel should be retained in the genus and that P. expulsum Olive & Stoianovitch should be reassigned to Soliformovum. The group most closely related to Protostelium, under this new concept, is the genus Planoprotostelium Olive & Stoianovitch, while Soliformovum is best treated as a genus of Eumycetozoa incertae sedis, though it does share some similarities with the group that includes the genera Ceratiomyxella Olive & Stoianovitch, Nematostelium Olive & Stoianovitch, and Schizoplasmodium Olive & Stoianovitch.