Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytoplasmic fractions from species of the Mollicutes genera Entomoplasma, Mesoplasma, Mycoplasma, and Acholeplasma were assayed for NADH oxidase (NADH ox), ATP- and PPi-dependent phosphofructokinase (PFK), ATP- and PPi-dependent deoxyguanosine kinase (dGUOK), thymidine kinase (TK), TMP kinase (TMPK), glucose-6-phosphate dehydrogenase (G6Pde), 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 Mollicutes metabolic and DNA repair pathways. This was the first study to determine the presence of these enzymes in members of the genera Entomoplasma and Mesoplasma. 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 PPi-dependent PFK, urease, dUTPase, and dGUOK activities. Entomoplasma ellychniae ELCN-1T (T = type strain), Entomoplasma melaleucae M-1T, Mesoplasma seiffertii F7T, Mesoplasma entomophilum TACT, Mesoplasma florum L1T, Mycoplasma fermentans PG18T, and Acholeplasma multilocale 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 PPi-dependent dGUOK, and UNG activities, but not dUTPase or G6Pde activities. In contrast, Acholeplasma equifetale C112T, Acholeplasma oculi 19LT, Acholeplasma hippikon C1T, Acholeplasma modicum PG49T, and Acholeplasma morum 72-043T had membrane-localized NADH ox activity, PPi-dependent PFK, G6Pde, and dUTPase activities, and significantly lower MDH and LDH activities and exhibited a faster rate with PPi than with ATP in the dGUOK reaction. All of the members of the Mollicutes tested had hypoxanthine-guanine phosphoribosyl transferase, phosphoenolpyruvate carboxylase, and (except for Mesoplasma entomophilum TAC(T)) UNG activities. All of the Acholeplasma strains except Acholeplasma multilocale PN525T had TK, TMPK, and UNG activities. Mesoplasma entomophilum TAC(T) 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. multilocale PN525T is a member of an unrecognized metabolic subgroup of the genus Acholeplasma or is not an Acholeplasma strain.
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PMID:Comparative metabolism of Mesoplasma, Entomoplasma, Mycoplasma, and Acholeplasma. 886 14

Mycoplasmas are parasitic bacteria with small genomes. Since parasitic bacteria need to adapt themselves to their hosts, there is a possibility that some genes evolved under species-specific constraint. We assume that Ureaplasma parvum has candidate genes that evolved in a species-specific manner in its genome. Here we examined synonymous-to-nonsynonymous substitution ratios (omega) of the 143 mycoplasma-orthologous genes of Ureaplasma and other mycoplasmas using branch models. As a result, the model allowing for Ureaplasma branch-specific omega in addition to omega of other mycoplasmas was significantly supported in 16 genes. First, the Ureaplasma-specific model was significantly supported in the genes encoding a transcription elongation factor and a transcription terminator factor, suggesting that transcription-related genes of Ureaplasma have evolved in a unique manner compared to those of other mycoplasmas. Second, the Ureaplasma-specific model was significantly supported in the gene encoding uracil-DNA glycosylase. In addition, the omega value of the gene in the Ureaplasma lineage was approximately 30-fold lower than those of other lineages, suggesting that uracil-DNA glycosylase of Ureaplasma evolved under stronger functional constraint than those of other mycoplasmas. Finally, three glycolytic genes of Ureaplasma were suggested to have evolved under relaxed selection. Among mycoplasmas, only Ureaplasma has urease and synthesizes ATPs via hydrolysis of urea. This raises the possibility that Ureaplasma does not need a glycolysis pathway for ATP synthesis. This unique energy-producing system may be related to the Ureaplasma-specific evolution of the glycolytic genes.
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PMID:Detection of the genes evolving under Ureaplasma-specific selection. 1841 24