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)

The final products of the arginine catabolism that can be utilized as a nitrogen source in Neurospora crassa are ammonium, glutamic acid, and glutamine. The effect of these compounds on arginase induction by arginine was studied. In wild-type strain 74-A, induction by arginine was almost completely repressed by glutamic acid plus ammonium, whereas ammonium or glutamic acid alone had only moderate effects. Arginine products of catabolism also repressed arginase induction. A mutant, ure-1, which lacks urease activity, hyperinduced its arginase with arginine as a nitrogen source. The addition of either ammonium or glutamine produced effects similar to those in the wild-type strain. The effect of ammonium on arginase induction is mediated through its conversion into glutamine. This was demonstrated in mutant am-1, which lacks L-glutamate dehydrogenase activity. In this mutant, the effect of glutamic acid was reduced, and, with ammonium, it was completely lost. The addition of glutamine or glutamic acid plus ammonium to this strain decreased by threefold the induction of arginase by arginine. Proline, a final product of arginine catabolism, competitively inhibited arginase activity. This effect and the repression of arginase by glutamine are examples of negative modulation of the first enzyme in a catabolic pathway by its final products.
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PMID:Nitrogen regulation of arginase in Neurospora crassa. 14 62

A restricted biochemical scheme for the identification of enterobacteria, consisting of 12 enzymatic tests, of which 7 performed on the multitest TSI and MIU media (H2S, the production of acid and gas from glucose, fermentation of lactose/saccharose, mobility, urease and indol production) and 5 additional tests performed separately : lysindecarboxylase, phenylalanindeaminase, beta galactosidase, increase on citrate media and splitting of sodium malonate is proposed. Of 7782 coprocultures, 275 were selected on TSI and MIU media as belonging to one of the groups of known pathogenic enterobacteria ; 94.87% of these cultures were correctly identified by using the 5 additional tests alone. Of the 14 cultures that could not be listed taxonomically, 10 gave atypical reactions with at least one of these tests. The current use of this restricted scheme and the use of the more extensive sets only in doubtful cases presents a real advantage by reducing the volume of work and materials under satisfactorily accurate conditions for identification.
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PMID:[Value of some enzyme tests used in practice for identification of enterobacteria]. 14 13

Analysis of heat stability of urease in extracts of 24 revertants, six for each of four ure loci, revealed that at least one revertant for each locus had a heat stability about one-third that of wild type. Similar results were obtained with urease formed by interallelic complementation at the ure-2 and ure-4 loci, but interallelic complementation at the ure-1 and ure-3 loci produced insufficient urease activity for analysis. The data are interpreted to suggest, as a tentative model, a structural function for each of the four ure loci.
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PMID:Reversion and interallelic complementation at four urease loci in Neurospora crassa. 15 55

Urease activity, expressed as mg N-NH3/g dry weight per 30 min at 25 degrees C, was determined in the various parts of the sheep, chicken and pig digestive apparatus. The results were as follows. Sheep: contents--rumen 1.25"/-0.09, reticulum 0.78+/-0.02, omasum 0.44+/-0.02, abomasum 0.002+/-0.001, duodenum 0.003+/-0.001, jejunum 0.18+/-0.03, ileum 0.42+/-0.03, caecum 1.34+/-0.11, colon 0.76+/-0.08, walls-rumen 0.88+/-0.16, reticulum 0.38+/-0.04, omasum 0.11+/-0.02, abomasum 0.01+/-0.002, ileum 0.092+/-0.01, caecum 0.14+/-0.03, colon 0.16+/-0.02. Chicken: contents--jejunum 0.028+/-0.009, ileum 0.043+/-0.013, caecum 0.17+/-0.03, colon and cloaca 0.04+/-0.013. Pigs: contents--jejunum 0.02+/-0.01, ileum 0.14+/-0.08, caecum 0.62+-0.12, colon 0.43+/-0.06. No urease activity was found in the walls of the digestive apparatus or the contents of the duodenum in chickens, or in the walls of the stomach and intestine and the contents of the duodenum in pigs. The results show that urease activity in the digestive apparatus of pigs and poultry is lower than in sheep. Inadequate urease activity in the digestive apparatus explains why chickens and pigs are significantly less capable than ruminants of utilizing urea nitrogen as a substitute for some of the protein in the diet.
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PMID:Urease activity in the contents and tissues of the sheep, pig and chicken gastrointestinal apparatus. 16 May 76

A simplified, concise scheme was developed for the identification of nonfermentative, gram-negative bacteria which have most frequently been reported in the literature as definite or possible agents of human disease. These organisms included apyocyanogenic Pseudomonas aeruginosa, P. fluorescens, P. putida, P. stutzeri, P. maltophilia, P. putrefaciens, P. cepacia, P. alcaligenes, FLAVOBACTERIUM SPECIES, Bordetella bronchiseptica, Acinetobacter anitratum (Herellea vaginicola), A. Iwoffi (Mima polymorpha), Moraxella species, Alcaligenes odorans and Alcaligenes species. The tests used for identification included production of cytochrome oxidase, amylase, deoxyribonuclease, gelatinase, urease and Beta-galactosidase; motility; oxidation of one per cent glucose and ten per cent lactose; fluorescence; indole, hydrogen sulfide and nitrogen gas production; denitrification of nitrites; growth at 42C; penicillin sensitivity and production of an aromatic odor and greenish discoloration on blood agar. Using this scheme, 85 per cent of 243 isolates (unknowns and reference strains) were identified to genus and species. Of the 15 per cent remaining, 11 per cent were identified as alkaline organisms and four per cent were unidentifiable.
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PMID:Identification of nonfermentative gram-negative bacteria in the clinical laboratory. 16 60

From the soil in the area around the Syowa Station, the East Ongul Island, the Antarctica, a total of 193 strains of clostridia were isolated and identified. It was surprising that the soil samples taken from the places which were considered to be scarcely contaminated by human beings and animals contained many clostridia. One hundred and fifty-five strains were assigned to 11 species, including C. perfringens, C. bifermentans, C. sordellii, C. sporogenes, C. plagarum, C. paraperfringens, C. septicum, C. tertium, C. cadaveris, C. butyricum and C. felsineum, but 38 strains remained unidentified. C. perfringens, C. bifermentans and C. sordellii were isolated very frequently and C. sporogenes less frequently. All the strains of C. sordellii were nonpathogenic and had almost the same characteristics as those of C. bifermentans except for the attitude in the urease test. The peculiar distribution and characteristics of the clostridia in the Antarctic soil were discussed in comparison with those found in the soil in Japan.
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PMID:Clostridia in soil of the Antarctica. 17 1

By counting the volatile molecules produced by an immobilized-enzyme catalyzed reaction which is interfaced to a mass spectrometer via a semi-permeable membrane, a general approach to biochemical measurement and detection is obtained which offers the potential of high sensitivity, specificity and speed. In combination with molecule microscopy, this method should allow, for example, a mapping of suitable enzyme distributions in non-stained and non-fixed tissue slices. Immobilized urease (urea amidohyrdrolase, EC 3.5.1.5) was used to assay urea using CO2 as the volatile product, and alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) was used to assay NADH using ethanol as the volatile product.
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PMID:Biochemical assay by immobilized enzymes and a mass spectrometer. 18 Oct 86

The authors prepared under experimental-industrial conditions paper indicator systems for the express identification of microbes, including carbohydrate discs (by the method of Nikitin et al.), and newly worked out types for the determination of the activity of cytochromoxidase, urease, indol formation, and indicator amino acid decarboxylases (lysin, ornithin, arginine). The use of paper indicator discs proved to be expedient for rationalization of laboratory diagnosis of bacterial intestinal infections.
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PMID:[Stable paper indicator systems for rapid identification of microorganisms]. 21 61

The localization of some enzymic activities in cell fractions of Ureaplasma urealyticum was studied. A quantitative evaluation of the effectiveness of several cell lysis procedures was obtained by using labeled membranes and sucrose density gradient centrifugation. Ultrasonic treatment was found to be the most effective procedure for lysing the cells, whereas digitonin and osmotic shock caused the lysis of only 70 and 50% of the cells, respectively. The localization of selected enzymes in Ureaplasma cells resembled that found in other Mycoplasma species. Adenosine triphosphatase, ribonuclease, deoxyribonuclease, and p-nitrophenylphosphatase activities were located exclusively in the membrane fraction, whereas urease and L-histidine ammonia-lyase were located in the cytoplasm.
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PMID:Cell fractions and enzymatic activities of Ureaplasma urealyticum. 21 22

The activities of three enzymes present in soil, phosphatases, urease, and decarboxylase, were monitered as indicators of the loss of biochemical information occurring when soil was sterilized by dry heat (0.08% relative humidity), gamma radiation, or a combination of both. More enzymatic activity was retained in soil sterilized by a long exposure to dry heat at relatively low temperature (8 weeks at 100.5 degrees C) than by a shorter exposure to a higher temperature (2 weeks at 124.5 degrees C). No enzymatic activity was detectable in soil sterilized by an even higher temperature (4 days at 148.5 degrees C). Soil sterilized with 7.5 Mrads of radiation retained much higher enzymatic activity than with heat sterilization. Combining sublethal doses of heat radiation effectively sterilized the soil and yielded enzymatic activities higher than those of soil sterilized by dry heat alone but lower than those of soil sterilized by radiation.
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PMID:Degradation of biochemical activity in soil sterilized by dry heat and gamma radiation. 21 35


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