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)

Helicobacter pylori (Hp) is considered as the major pathogen in Hp-associated gastritis but the mechanism of its action has not been fully explained. We investigated both the damaging and protective effects of intragastric (i.g.) application of ammonia (NH4OH) and ammonium ion (NH4Cl), the major products of Hp-derived urease, on the rat stomach with intact and capsaicin-deactivated sensory nerves or suppressed prostaglandin (PG) and nitric oxide (NO) synthesis. NH4OH given i.g. resulted in a concentration-dependent mucosal damage starting at 30 mM and reaching maximum at 250 mM (pH 11), the extent of damage being similar to that obtained with 100% ethanol. NaOH solution (1 mM) at pH 11 given i.g. did not affect mucosal integrity. The damage caused by NH4OH was accompanied by the fall in gastric blood flow (GBF) reaching at 250 mM NH4OH about 30% of the vehicle control value. The NH4OH-induced gastric damage was augmented by capsaicin-induced deactivation of sensory nerves, the suppression of nitric oxide (NO) synthase with L-NAME or the decrease of i.g. acidity by ranitidine. The pretreatment with scavengers of reactive oxidants significantly reduced the area of NH4OH-induced gastric lesions. When the mucosa was first exposed to a low 15-mM concentration of NH4OH and then insulted with large 250 mM NH4OH or with 100% ethanol, the lesion area was markedly reduced as compared to that obtained with 250 mM NH4OH or 100% ethanol alone. This adaptive protection by 'mild' concentration of NH4OH against strong irritants (250 mM NH4OH or 100% ethanol) was reversed, in part, by pretreatment with L-NAME and indomethacin. NH4Cl (60-500 mM) given i.g. alone failed to affect the mucosal integrity but when applied before 100% ethanol it produced a concentration-dependent fall in the mucosal damage by these irritants. We conclude that; (1) ammonia at higher concentrations damages the gastric mucosa, while ammonium ion exerts the protective activity; (2) the ammonia-induced gastric damage may involve the formation of reactive oxidants; (3) ammonia at lower concentration acts like a mild irritant via the activation of sensory nerves, NO-arginine pathway and PG.
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PMID:Gastric mucosal damage and adaptive protection by ammonia and ammonium ion in rats. 891 6

Genital mycoplasmas play an important role in genitourinary tract disease. The purpose of this study was to isolate M. hominis and U. urealyticum from vaginal and throat swabs and urine from women sexually active or not. Samples were taken from women with (cases) or without (controls) genitourinary tract disease and were dipped inoculated into 1 ml of E broth with arginine or urea and ten-fold dilutions were done. Samples were incubated at 37 degrees C until phenol red indicator changed to color purple. Identification of species was done by polymerase chain reaction technique. M. hominis was identified with oligonucleotides that correspond to the nucleotide sequence of 16S rRNA gene and U. urealyticum was identified with oligonucleotides that correspond to the nucleotide sequence of the urease gene (Blanchard et al.). There was no statistical difference (X2 P > .05) between isolation percentages from vaginal swabs, while there was statistical difference between urine samples. These mycoplasmas were isolated in higher percentages from pubertal girls and were recovered until the fifth ten-fold dilution both from vaginal swabs and urine. For throat swabs they were only recovered from sexually active women.
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PMID:Detection of Mycoplasma hominis and Ureaplasma urealyticum in women sexually active or not. 898 7

The Bacillus subtilis ureABC operon encodes homologs of the three subunits of urease enzymes of the family Enterobacteriaceae. Disruption of ureC prevented utilization of urea as a nitrogen source and resulted in a partial growth defect in minimal medium containing limiting amounts of arginine or allantoin as the sole nitrogen source.
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PMID:The Bacillus subtilis ureABC operon. 915 Feb 40

Bestatin, an aminopeptidase inhibitor, permits the degradation of cellular proteins to di- and tripeptides but interferes with the further breakdown of these peptides to amino acids. We propose to measure instant rates of protein degradation in skeletal muscles of intact mice by the accumulation of bestatin-induced intermediates. Muscle protein was labeled by injection of L-[guanidino-14C]arginine; 3 days later, maximum accumulation of intermediates was measured in abdominal wall muscles 10 min after the intravenous injection of 5 mg of bestatin. The peptides were partially purified and hydrolyzed in 6 N HCl, and the radioactivity in peptide-derived arginine was determined, after conversion to 14CO2 by treatment with arginase and urease. The measurement of bestatin-induced intermediates provides a unique tool for studying acute changes in muscle protein turnover in live mice. We observed a 62% increase in muscle protein breakdown after a 16-h fast, which was reversed by refeeding for 3.5 h, and a 38% increase after 3 days of protein depletion.
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PMID:Measurement of muscle protein degradation in live mice by accumulation of bestatin-induced peptides. 943 31

Incubation of mixed human saliva with arginine, ornithine, and proline for 30 min to 2 h at 40 degrees C leads to an appreciable consumption of the above amino acids. The rate of utilization is 0.2 to 0.5 ncat/ml of saliva. The rate of urea loss is higher by an order of magnitude: up to 11 ncat/ml. Putrescin, urea (after incubation with arginine), and ammonium are identified as the products of these reactions. The biological significance of such reactions is believed to consist in neutralization of carbohydrate fermentation products. The detected consumption of amino acids and urea indicates that mixed human saliva contains urease, arginase, ornithine decarboxylase, and, probably, proline reductase. Since the origin of these enzymes is probably bacterial, changes in their activity in the saliva can be regarded as an indicator of dysbacteriosis and a diagnostically important parameter.
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PMID:[The utilization of amino acids and urea by human oral fluid]. 947 2

Arginase (EC 3.5.3.1) transcript level and activity were measured in soybean (Glycine max L.) embryos from the reserve deposition stage to postgermination. Using a cDNA probe for a small soybean arginase gene family, no transcript was detected in developing embryos. However, arginase transcripts increased sharply on germination, reaching a maximum at 3 to 5 d after germination. There was low but measurable in vitro arginase specific activity in developing embryos (less than 6% of seedling maximum). During germination arginase specific activity increased in parallel with the sharply increasing arginase transcript level. Seedling arginase activity was largely localized in cotyledons. Arginase activity was assayed in vivo by measuring urea accumulation in a urease-deficient mutant. No urea was detected in developing embryos, whereas accumulated urea paralleled arginase specific activity and transcript level in germinating seedlings. As in planta embryos, cultured cotyledons did not accumulate urea when arginine (Arg) was provided with other amino acids in a "mock" seed-coat exudate. Arg as the sole nitrogen source was converted to urea but did not support cotyledon growth. There appeared to be a lack of recruitment of the low-level arginase activity to hydrolyze free Arg in developing embryos, thus avoiding a futile urea cycle.
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PMID:Arginase is inoperative in developing soybean embryos. 988 Mar 72

Spiral organisms were isolated from an antral gastric mucosal biopsy specimen from a dyspeptic patient with gastritis. Only corkscrew-shaped organisms resembling "Gastrospirillum hominis" ("Helicobacter heilmannii") but no Helicobacter pylori-like organisms were seen in histological sections. H. pylori was not cultured from specimens from this patient. On the basis of biochemical reactions, morphology, ultrastructure, and 16S DNA sequencing, the isolated "G. hominis" was shown to be a true Helicobacter sp. very similar to Helicobacter felis and the "Gastrospirillum" but was separate from H. pylori. "G. hominis" is a pleomorphic gram-negative cork-screw-shaped, motile rod with 3 to 8 coils and a wavelength of about 1 micrometer. In contrast to H. pylori, it has up to 14 sheathed flagellar uni- or bipolar fibrils but no periplasmic fibrils. "G. hominis" grows under microaerobic conditions at 36 and 41 degrees C on 7% lysed, defibrinated horse blood agar plates within 3 to 7 days and can be subcultured under microaerobic but not under anaerobic conditions on media similar to those used for H. pylori and H. felis. The small translucent colonies were, in contrast to those of H. felis, indistinguishable from those of H. pylori. "G. hominis" is, like H. pylori and H. felis, motile, is oxidase, catalase, nitrite, nitrate, and urease positive, and produces alkaline phosphatase and arginine arylamidase. Like H. pylori and H. felis, it is sensitive to cephalothin (30-microgram disc), resistant to nalidixic acid (30-microgram disc), and sensitive to most other antibiotics. The 16S DNA sequence clusters "G. hominis" together with "Gastrospirillum," H. felis, Helicobacter bizzozeronii, Helicobacter salmonii, Helicobacter nemestrinae, Helicobacter acinonychis, and H. pylori.
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PMID:Characterization of a culturable "Gastrospirillum hominis" (Helicobacter heilmannii) strain isolated from human gastric mucosa. 1007 28

Parabens were found to be potent inhibitors of alkali production from arginine by oral streptococci such as Streptococcus rattus, Streptococcus sanguis and Streptococcus gordonii. For example, 2 mumol butylparaben per ml completely and irreversibly inhibited arginolysis by intact cells of S. rattus FA-1 and was lethal for the organism. In contrast, butylparaben was not a very effective inhibitor of ureolysis by intact cells of Streptococcus salivarius 57.I, although it did kill the cells. Butylparaben irreversibly inhibited the cytoplasmic enzymes arginine deiminase, carbamate kinase and urease in permeabilized cells or isolated form. However, inhibition of arginolysis by intact cells appeared to be due primarily to irreversible inhibition of transport systems for arginine uptake, because butylparaben added to intact cells did not reduce levels of arginine deiminase when the cells were subsequently permeabilized after washing. The insensitivity of ureolysis by intact cells to butylparaben can be related to the known high permeability of cell membranes to urea and the cytoplasmic location of urease. The potency of butylparaben as an inhibitior of arginolysis or glycolysis and as a lethal agent was found to be greater at acid pH that at neutral or alkaline pH.
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PMID:Membrane locus and pH sensitivity of paraben inhibition of alkali production by oral streptococci. 1055 Nov 69

Arginase of the Helicobacter pylori urea cycle hydrolyzes L-arginine to L-ornithine and urea. H. pylori urease hydrolyzes urea to carbon dioxide and ammonium, which neutralizes acid. Both enzymes are involved in H. pylori nitrogen metabolism. The roles of arginase in the physiology of H. pylori were investigated in vitro and in vivo, since arginase in H. pylori is metabolically upstream of urease and urease is known to be required for colonization of animal models by the bacterium. The H. pylori gene hp1399, which is orthologous to the Bacillus subtilis rocF gene encoding arginase, was cloned, and isogenic allelic exchange mutants of three H. pylori strains were made by using two different constructs: 236-2 and rocF::aphA3. In contrast to wild-type (WT) strains, all rocF mutants were devoid of arginase activity and had diminished serine dehydratase activity, an enzyme activity which generates ammonium. Compared with WT strain 26695 of H. pylori, the rocF::aphA3 mutant was approximately 1, 000-fold more sensitive to acid exposure. The acid sensitivity of the rocF::aphA3 mutant was not reversed by the addition of L-arginine, in contrast to the WT, and yielded a approximately 10, 000-fold difference in viability. Urease activity was similar in both strains and both survived acid exposure equally well when exogenous urea was added, indicating that rocF is not required for urease activity in vitro. Finally, H. pylori mouse-adapted strain SS1 and the 236-2 rocF isogenic mutant colonized mice equally well: 8 of 9 versus 9 of 11 mice, respectively. However, the rocF::aphA3 mutant of strain SS1 had moderately reduced colonization (4 of 10 mice). The geometric mean levels of H. pylori recovered from these mice (in log(10) CFU) were 6.1, 5.5, and 4.1, respectively. Thus, H. pylori rocF is required for arginase activity and is crucial for acid protection in vitro but is not essential for in vivo colonization of mice or for urease activity.
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PMID:Helicobacter pylori rocF is required for arginase activity and acid protection in vitro but is not essential for colonization of mice or for urease activity. 1057 36

Conventional biochemical tests were compared with reactions in a multiple test system, MicroScan Walkaway (Dade Diagnostic Inc. MicroScan Divison, West Sacramento, California) in conjugation with the Combo Pos ID Panels (Dade Diagnostic Inc. MicroScan Divison, West Sacramento, California), in order to evaluate the accuracy for the identification of 99 clinical isolates of Staphylococcus spp. and five reference strains. False-negative or positive reactions were detected from Voges-Proskauer, urease and mannose tests. A good correlation was found among the two identification systems for the fermentation of trehalose, lactose, raffinose, as well as for arginine dyhydrolase, esculin hydrolisis and nitrate reduction. From the results of the present study, it is concluded that the MicroScan Walkaway system is a reliable method for identification of staphylococci (94.23%), although 8.2% could be identified to the species level only after use of additional test.
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PMID:Evaluation of the MicroScan system for identification of staphylococci. 1062 74


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