MYCOPLASMA-SOMNILUX SP-NOV, MYCOPLASMA-LUMINOSUM SP-NOV, AND MYCOPLASMA-LUCIVORAX SP-NOV, NEW STEROL-REQUIRING MOLLICUTES FROM FIREFLY BEETLES (COLEOPTERA, LAMPYRIDAE)

Strain PYAN-1(T) (T = type strain), which was isolated from a pupal gut of the firefly beetle Pyractonema angulata, and strains PIMN-1(T) and PIPN-2(T), which were isolated from guts of adult Photinus marginalis and Photinus pyralis fireflies, respectively, were demonstrated to be sterol-requiring mollicutes. Cells of the three strains were shown by electron and dark-field microscopy to be small, pleomorphic, nonhelical, nonmotile bodies surrounded by single membranes. No evidence of a cell wall was observed, and the organisms were not susceptible to 500 U of penicillin per ml. The three strains grew rapidly in SP-4 broth medium. Strains PIMN-1(T) and PIPN-2(T) grew in medium supplemented with bovine serum fraction, but strain PYAN-1(T) did not. All three strains grew on solid media when the cultures were incubated aerobically, but only strains PYAN-1(T) and PIPN-2(T) formed colonies when anaerobic conditions were employed. The three strains catabolized glucose but hydrolyzed neither arginine nor urea. All of the strains grew at temperatures of 18 to 32°C; strains PYAN-1(T) and PIMN-1(T) also grew at 10°C. The optimal temperature for growth for strains PYAN-1(T) and PIPN-2(T) was 30°C; strain PIMN-1(T) grew equally well at 30 or 32°C. None of the three strains grew at 37°C. The genome sizes of strains PYAN-1(T), PIMN-1(T), and PIPN-2(T) were about 527 (478 to 589), 570 (480 to 630), and 762 (635 to 871) megadaltons, respectively. The guanine-plus-cytosine contents of the DNAs of the strains, as determined by buoyant density, thermal denaturation, and high-performance liquid chromatography methods, were as follows: 27.4, 30.2, and 27.5 mol%, respectively, for strain PYAN-1(T); 28.8, 31.2, and 29.2 mol%, respectively, for strain PIMN-1(T); and 28,4, 30.4 and 31.2 mol%, respectively, for strain PIPN-2(T). All three strains were serologically unrelated to the type strains of previously established Mycoplasma species (including Mycoplasma ellychniae), to each other, and to 15 other unclassified sterol-requiring strains isolated from animals, plants, and insects. Along with M. ellychniae, these three organisms represent an unusual cluster of strains belonging to the genus Mycoplasma isolated from insects. Strain PYAN-1 (= ATCC 49194) is the type strain of Mycoplasma somnilux sp. nov.; strain PIMN-1 (= ATCC 49195) is the type strain of Mycoplasma luminosum sp. nov.; and strain PIPN-2 (= ATCC 49196) is the type strain of Mycoplasma lucivorax sp. nov.