A spiroplasma recovered from allantoic fluids of chick embryos infected with the tick-derived suckling mouse cataract agent was grown in continuous passage on a new artificial culture medium. The cultured organisms induced typical ocular and other disease symptoms in susceptible animals, and were reisolated from involved host tissues. Although spiroplasmas have been previously recognized as plant and insect pathogens, this is the first spiroplasma shown to multiply at 37 degrees C and to be pathogenic for vertebrates.
Cytoplasmic fractions from species of the Mollicutes genera Entomoplusma, Mesoplasma, Mycoplusma, and Acholeplusma were assayed for NADH oxidase (NADH ox), ATP-and PP,-dependent phosphofructokinase (PFK), ATP-and PP,-dependent deoxyguanosine kinase (dGUOK), thymidine kinase (TK), TMP kinase (TMPK), glucose-6-phosphate dehydrogenase (MPde), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), phosphoenolpyruvate carboxylase, hypoxanthine-guanine phosphoribosyl transferase, dUTPase, and uracil-DNA glycosylase (UNG) activities. Membrane fractions were also examined for NADH ox activity. These activities were used as indicators of the presence and relative activities of major MoZZicutes metabolic and DNA repair pathways. This was the first study to determine the presence of these enzymes in members of the genera Entomoplusma and Mesoplusma. Using the data obtained, we constructed a preliminary scheme for distinguishing genera of the class Mollicutes on the basis of the results of signature functional enzyme assays. This scheme includes phylogenetic relationships deduced from rRNA analyses, but is more informative with respect to metabolic potential. The criteria used include the presence of PP,-dependent PFK, urease, dUTPase, and dGUOK activities. Entomoplasma ellychniae ELCN-lT (T = type strain), Entomoplasma meluleucae M-lT, Mesoplasma segertii F7T, Mesoplusma entomophilum TACT, Mesoplusma jlorum LIT, Mycoplusma fermentans PGIST, and AchoZeplasma multibcale PN525T were similar in most respects. NADH ox activity was localized in the cytoplasm of these organisms. These strains had ATP-dependent PFK, MDH, LDH, ATP-and PP,-dependent dGUOK, and UNG activities, but not dUTPase or G6Pde activities. In contrast, Acholeplusma equifetale C112T, Acholeplasma oculi 19LT, Acholeplasma hippikon CIT, Acholeplusma modicum PG49T, and Acholeplasma momm 72-043T had membrane-localized NADH ox activity, PP,-dependent PFK, G6Pde, and dUTPase activities, and significantly lower MDH and LDH activities and exhibited a faster rate with PP, than with ATP in the dGUOK reaction. All of the members of the MoZZicutes tested had hypoxanthine-guanine phosphoribosyl transferase, phosphoenolpyruvate carboxylase, and (except for Mesoplasma entomophilum TACT) UNG activities. All of the Acholeplusma strains except Acholeplusmu multilocale PN52ST had TK, TMPK, and UNG activities. Mesoplusma entomophilum TACT was distinguished by having no detectable dUTPase, UNG, TK, and TMPK activities, indicating that there is a severe restriction in or an absence of a synthetic route to dTTP. Our data also suggest that A. multiZocale PN52ST is a member of an unrecognized metabolic subgroup of the genus Acholeplusm or is not an Acholeplusma strain.Distinguishing members of the class Mollicutes by their metabolic characteristics has been of very limited phylogenetic and taxonomic usefulness. Standards for describing Mollicutes taxa have been published previously (7). Characteristics such as gross cellular morphology, colonial appearance, genome size, and serologic...
We tested the ability of 62 growing strains belonging to the class Mollicutes to reduce the redox indicator and free-radical generator 1,1'-dibenzyl-4,4'-bipyridinium dichloride (benzyl viologen [BV]) to a blue-violet-purple color. BV was reduced by 12 Acholeplasma species but not by Acholeplasma multiforme PN525T (T = type strain). BV was also reduced by five of nine Mesoplasma species and by four of six Entomoplasma species. BV was not reduced by 19 Mycoplasma species, six Spiroplasma species, five unnamed Spiroplasma strains belonging to different serogroups, three Ureaplasma species, and one unnamed Ureaplasma strain. The BV-reducing ability was localized in the membrane of Acholeplasma laidlawii B-PG9 and was dependent on NADH. Reduction of BV could be expressed in mixed cultures, and this activity may be useful for recognizing the contaminating presence of an Acholeplasma species. The reductive BV response may have phylogenetic value. We believe that the test described in this paper readily distinguishes all Acholeplasma species and some Mesoplasma and Entomoplasma species from all Mycoplasma, Spiroplasma, and Ureaplasma species tested.
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