Isolation, Characterization, and Emendation of Description of Angiococcus disciformis (Thaxter 1904) Jahn 1924 and Proposal of a Neotype Strain

Abstract

Strain CMU-1, identified as a member of Angiococcus disciformis (Thaxter) Jahn 1924, was isolated from aquatic habitats in the fossa region of Davis Lake (Vestaburg Bog), Michigan. The myxobacter produced orange fruiting bodies consisting of numerous disk-shaped to oblate spheroid-shaped sporangia (average, 40 by 27 µm; 15 µm thick). The sporangia comprising the fruiting body occurred singly or were clumped in irregular masses upon a solid substrate. Mature myxospores ranged in shape from irregular spheres (1 µm in diameter) to ovals (1 by 1.5 µm). Vegetative rods were motile by gliding and measured 0.5 to 0.75 by 3 to 14 µm. The guanine plus cytosine content of the deoxyribonucleic acid extracted from A. disciformis CMU-1 was 68.4 mol%. Strain CMU-1 (ATCC 33172) has the properties recorded in the original description of Myxococcus disciformis by Thaxter, and it is herein proposed as the neotype strain of this organism. Because the myxospores were contained within sporangia, the organism cannot belong to the genus Myxococcus, and we propose that it properly belongs in the genus Angiococcus Jahn 1924.