Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Using dialyzing cultures of T-strain mycoplasmas, it was possible to make some observations relevant to the growth and metabolism of these organisms which would not be possible in nondialyzing cultures due to growth inhibition of the organisms by elevated pH and increased ammonium ion concentration in media containing urea. The rate of ammonia accumulation was found to be related to the initial urea concentration in the medium and could not be accounted for by any change in the multiplication rate of the organisms. More ammonia was generated than could be accounted for by the added urea alone, suggesting that an ammonia-producing activity other than urease may be present in T-strain mycoplasmas. Titers above 10(7) color change units per ml were achieved in dialysis cultures of a T-strain mycoplasma in the presence of urea, and such titers were maintained for approximately 60 h during dialysis culture in the absence of added urea.
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PMID:Dialysis culture of T-strain mycoplasmas. 459 3

A previously unknown metabolite necessary for growth of T strains of Mycoplasma in artificial culture media has been identified as urea. The source of this metabolite was the mammalian plasma or serum enrichment of the culture medium. Normal horse serum was the most satisfactory native protein enrichment for cultivation of T strains of mycoplasma, and it is believed that its superior performance in agar and fluid culture media is associated with its relatively high urea content (approximately 40 mg/100 ml). T-strain urease activity was maximal at pH 6.0 +/- 0.5. This is also the optimal pH for growth of T strains. Substrate concentrations greater than 1.0% urea were inhibitory to growth and urease activity of T-strain organisms, and optimal urea concentrations in fluid media appeared to lie within the range of 0.008 to 0.01 m. This range of urea concentration permitted maximal growth of T-strain organisms without rapid loss of viability due to excessive ammonia accumulation and rise in pH to lethal levels. T strains of Mycoplasma were cultivated in a serum-free fluid medium containing urea as the only added metabolite and nitrogen source. T strains are the only known human mycoplasmas which exhibit urease activity, and this biochemical marker can be employed as an aid in the detection and identification of T strains of Mycoplasma (urease color test) and in distinguishing T strains from other members of the human Mycoplasma group.
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PMID:Occurrence of urease in T strains of Mycoplasma. 602 39

An ELISA utilising a urease-antibody conjugate specific to chicken IgG was examined as an alternative to the serum agglutination and the haemagglutination inhibition tests in the diagnosis of Mycoplasma gallisepticum and M. synoviae infections in poultry. Use of a urease conjugate allowed the serum reactions to be appraised without the need for expensive photometric equipment. Non-specific binding of conjugate to antigen was eliminated by treatment of antigen coated microplates with 10% foetal calf serum in phosphate buffered saline. Some chicken serums produced non-specific reactions. These reactions were reduced without any loss of test sensitivity by making the initial 1:5 dilution of chicken serum in whole sheep serum rather than diluting buffer. Tests on serums from experimentally infected chickens showed that the urease ELISA was specific, and was as sensitive as the serum agglutination test but more sensitive than the haemagglutination inhibition test.
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PMID:A urease-ELISA for the detection of mycoplasma infections in poultry. 637 68

Ureaplasma urealyticum and Mycoplasma hominis, separately or together, were co-isolated along with 34 of 102 strains of Neisseria gonorrhoeae cultured from urethral swabs from men with urethritis. For approximately half of the N. gonorrhoeae strains, the mycoplasma(s) persisted for at least five passages on agar medium. U. urealyticum was isolated in 31 of the 34 instances. No association between particular serotype(s) of U. urealyticum or auxotypes of N. gonorrhoeae was identified. The auxotypes of the N. gonorrhoeae isolates were not altered by the presence of U. urealyticum. To screen cultures of N. gonorrhoeae for the presence of genital mycoplasmas, we recommend direct microscopy of growth on agar: for M. hominis, after the colony epifluorescence test, and, for U. urealyticum, after the urease spot test.
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PMID:The co-existence of genital Mycoplasma and Neisseria gonorrhoeae isolated from the male urethra. 643 16

Struvite urinary stones are commonly associated with infections by urease possessing bacteria (Proteus). Ureaplasma urealyticum, a genital mycoplasma, is predominantly located in the human genito-urinary tract and produces urease. Its possible role in the formation of infection stones was studied in the rat model described by Friedlander and Braude. Struvite bladder stones were produced in 60% of Sprague-Dawley male rats after infection of ureaplasmas (serotype 1, 2, 3, 7) into the renal medulla. Mycoplasma hominis, another genital mycoplasma, produced bladder stones in only 10% of animals. A kinetic study showed that pure struvite stones appeared into the bladder 4 to 5 days after inoculation and that U. urealyticum did not usually remain viable more than 6 days. Acetohydroxamic acid and doxycycline prevented the formation of the stones.
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PMID:[Experimental magnesium ammonium phosphate lithiasis induced by Ureaplasma in the rat]. 653 Oct 60

The formation of some urinary tract stones (struvite stones) is known to be related to infection by urease-possessing microorganisms, such as Proteus sp. and some other bacteria. Ureaplasma urealyticum, a genital mycoplasma, contains also urease and is predominantly located in the urogenital tract. Its significance in the production of human urinary stones has not yet been elucidated. In this study, 135 human calculi obtained by surgery were analysed chemically and were cultured for the presence of conventional bacteria and U. urealyticum, 51 were ammonium magnesium phosphate stones and contained Proteus (27), E. coli (4), Staphylococcus epidermidis (3), Streptococcus D (2), Pseudomonas aeruginosa (1), Staphylococcus aureus (1), Corynebacterium (1), Candida albicans (1). U. urealyticum was isolated in one patient, from two different calculi (left and right) taken after an interval of fifteen days. Different bacteria were isolated from other calculi (oxalate, uric acid). This findings suggest that Ureaplasma urealyticum should be looked for in struvite calculi.
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PMID:[Comparative bacteriological and chemical analysis of kidney calculi. Apropos of 135 cases]. 653 Oct 61

Flurofamide (N-[diaminophosphinyl]-4-fluorobenzamide), a urease inhibitor, was a potent inhibitor of the growth of Ureaplasma urealyticum. As little as 10 microM flurofamide (2 micrograms/ml) prevented any growth, but U. urealyticum survived for about eight hours before colony counts become undetectable. Flurofamide was a specific inhibitor of U. urealyticum since it did not inhibit growth of four Mycoplasma species or Acholeplasma hippikon. Flurofamide was 1,000 times more active than acetohydroxamic acid and thus has promise as a chemotherapeutic agent and a biochemical tool.
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PMID:Inhibition of the growth of Ureaplasma urealyticum by a new urease inhibitor, flurofamide. 667 52

On the basis of the nucleotide sequence of the urease genes of Ureaplasma urealyticum serotype 8, polymerase chain reaction (PCR) primers were selected, evaluated for specificity and sensitivity, and tested for their ability to detect U. urealyticum in the adult urogenital tract, amniotic fluid, and endotracheal aspirates of newborns. All 14 reference serotypes of U. urealyticum were detected with equal sensitivity (1-10 cfu), whereas multiple strains of 12 other mycoplasma species found in humans as well as eukaryotic DNA were not detected. A total of 638 clinical specimens was evaluated. Results indicate that PCR is equal to if not more sensitive than culture for detection of U. urealyticum. Faster detection of U. urealyticum by PCR (< 24 h) compared to culture (2-5 days) will be particularly important in management of very low birth-weight infants in whom this organism has been shown to be a significant cause of meningitis, respiratory disease, and death. This method of detection will also be helpful in further determining the role of this organism in intraamniotic infection and premature birth.
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PMID:Detection of Ureaplasma urealyticum by polymerase chain reaction in the urogenital tract of adults, in amniotic fluid, and in the respiratory tract of newborns. 839 6

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

Ureaplasma gallorale is a urease-containing mycoplasma (a member of the Mollicutes) which is pathogenic for chickens, from which it was originally isolated. We amplified the 16S rRNA gene of this bacterium and then cloned and sequenced the amplicon. A phylogenetic analysis based on an alignment of the 16S rRNA sequences of U. gallorale and several other Ureaplasma species revealed that U. gallorale is more closely related to Ureaplasma urealyticum than to other Ureaplasma species.
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PMID:Ureaplasma gallorale, an isolate from chickens, is most closely related to the human isolate, U. urealyticum. 886 56


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