Comparative Metabolism of Mesoplasma, Entomoplasma, Mycoplasma, and Acholeplasma

Abstract

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...

Sugar uptake byMycoplasma mycoides strain PT994 andMycoplasma canis strain 85 B97

“…What is clear is that the apparent absence of any extracellular hydrolysis of maltose by Mycoplasma mycoides strain PT994 is consistent with the operation of a specific maltose transport system that is only marginally affected by glucose. Transport systems for sugars in mycoplasmas are known to include glucose phosphotransferase, ABC transporters, and other PEP:phosphotransferases (Razin and Cirillo, 1973;Pollack et al, 1996;Halbedel et al, 2004;Razin, 2006). The inhibitory effect of fluoride on the metabolism of glucose, sucrose and fructose suggests inhibition of the enolase of glycolytic fermentation, which is involved in the metabolism of glucose from all three substrates.…”

“…In many mycoplasmas, ATP generation for biosynthesis depends on the fermentation of sugars to lactate, which may be further oxidized to acetate Pollack et al, 1996). Glucose is the preferred sugar for many fermentative mycoplasmas and can support higher growth rates and yields than maltose or sucrose, but some species use these disaccharides with affinities comparable to those for glucose (AbuGroun et al, 1994;Megid et al, 2001).…”

“…mycoides Large Colony (LC) type can grow with either glucose or maltose (Miles and Lee, 1983), and Mycoplasma canis uses both glucose and sucrose (Megid et al, 2001). Glucosefermenting mycoplasmas use the Embden-Meyerhof-Parnas glycolytic pathway for glucose fermentation (Pollack et al, 1996) and sugar uptake can be by more than one mechanism including the phosphoenolpyruvate (PEP):sugar phosphotransferase system (Rottem and Razin, 1969;Haldebel et al, 2004), but little is known about the regulation of sugar uptake when more than one sugar is available. As obligate saprophytes and pathogens, mycoplasmas are likely to encounter such multiple choices in their hosts, and we have compared the responses of strains of two pathogenic species, isolated from animals with respiratory disease, when pairs of sugars were provided as energy substrates.…”

Revised minimal standards for description of new species of the class Mollicutes (division Tenericutes)

“…Mollicutes have diverse metabolic pathways (McElwain et al, 1988;Pollack et al, 1989Pollack et al, , 1996bPollack et al, , 1997Miles, 1992;Pollack, 1992), but the implementation of tests reflecting comparative metabolism of mollicutes has posed many challenges . Improvements in test protocols (Miles & Nicholas, 1998) may now make it possible to utilize certain metabolic characterizations more fully in mollicute taxonomy.…”

Differential Inhibition of Mollicute Growth: an Approach to Development of Selective Media for Specific Mollicutes

“…Acholeplasma spp. possess pathways for the fermentation of sugars to lactate and the oxidation of lactate or pyruvate to acetate plus carbon dioxide (18). The diversity of energy generation among Mycoplasma spp.…”