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)

Proteus mirabilis, a common cause of urinary tract infection, produces a potent urease that hydrolyzes urea to NH3 and CO2, initiating kidney stone formation. Urease genes, which were localized to a 7.6-kilobase-pair region of DNA, were sequenced by using the dideoxy method. Six open reading frames were found within a region of 4,952 base pairs which were predicted to encode polypeptides of 31.0 (ureD), 11.0 (ureA), 12.2 (ureB), 61.0 (ureC), 17.9 (ureE), and 23.0 (ureF) kilodaltons (kDa). Each open reading frame was preceded by a ribosome-binding site, with the exception of ureE. Putative promoterlike sequences were identified upstream of ureD, ureA, and ureF. Possible termination sites were found downstream of ureD, ureC, and ureF. Structural subunits of the enzyme were encoded by ureA, ureB, and ureC and were translated from a single transcript in the order of 11.0, 12.2, and 61.0 kDa. When the deduced amino acid sequences of the P. mirabilis urease subunits were compared with the amino acid sequence of the jack bean urease, significant amino acid similarity was observed (58% exact matches; 73% exact plus conservative replacements). The 11.0-kDa polypeptide aligned with the N-terminal residues of the plant enzyme, the 12.2-kDa polypeptide lined up with internal residues, and the 61.0-kDa polypeptide matched with the C-terminal residues, suggesting an evolutionary relationship of the urease genes of jack bean and P. mirabilis.
J Bacteriol 1989 Dec
PMID:Proteus mirabilis urease: nucleotide sequence determination and comparison with jack bean urease. 268 33

Acetohydroxam acid (500-1000 mg/d) inhibit the activity of the bacterial urease successfully due to reduction of ammonia excretion and urinary pH value in the patients. Acetohydroxam acid should be used in patients after operative treatment of urolithiasis due to infection with carbamidesplitting bacteria.
Z Urol Nephrol 1989 Dec
PMID:[Acetylhydroxamic acid in the treatment of nephrolithiasis, caused by infection with urease forming microorganisms]. 269 24

A microwell enzyme immunoassay (Visuwell) for direct detection of Group A streptococcal antigen from throat swab specimens has been developed. It incorporates urease conjugated antibody as the detector and is easily interpreted by a yellow to purple color change. Throat specimens obtained on rayon-tipped swabs were transported moist in modified Stuarts medium and cultured before being tested in Visuwell (n = 585, prevalence 17.1%, sensitivity 88%, specificity 92.4%, predictive value positive 70.4%, predictive value negative 97.4%, and accuracy 91.6%). In instances of discrepancy between culture and Visuwell, throat swab extracts were tested in a latex agglutination test. In 21 of 37 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Throat specimens obtained using double rayon swabs and transported to the laboratory dry had one swab cultured and the other tested in Visuwell (n = 280, prevalence 20.4%, sensitivity 75.4%, specificity 88.3%, predictive value positive 62.3%, predictive value negative 93.4%, and accuracy 85.7%). When 1+ culture positive specimens were considered negative, a sensitivity of 97.6% was obtained. In 14 of 26 instances of Visuwell-positive, culture-negative specimens, latex agglutination was positive. Cross-reaction with organisms other than Group A Streptococcus found in the oropharynx was negligible in Visuwell. Limit of detection of Group A streptococcal antigen was equivalent for Visuwell and latex agglutination.
Diagn Microbiol Infect Dis 1988 Dec
PMID:Comparison of Visuwell enzyme immunoassay to culture for detection of group A Streptococcus in throat swab specimens. 307 46

Vesical foreign bodies readily lead to urolith formation but not in Brattleboro rats with diabetes insipidus. This experiment was designed to examine the roles of vesical foreign bodies, urine osmolality, and vesical infection in the formation of uroliths and associated reactive urothelial hyperplasia. ADH-deficient Brattleboro rats received surgical insertion of a silk suture in the bladder. Their bladders were infected with intravesical injection of urease positive P. vulgaris, while controls were similarly injected with sterile Ringer's sol. They received daily injections of either pitressin tannate in oil (1 U/kg body weight) or peanut oil. Urine flow rate, urine osmolality, urine culture, and gross and light microscopic examinations of the bladders were carried out at the end of 4th week. The results indicated that uroliths readily formed in the presence of all three factors; vesical foreign bodies, high urine osmolality, and infection, but not as readily in the presence of two or less of these three factors. The urothelial hyperplasia was prominent in infected bladders followed by non-infected bladder with high osmolar and low osmolar urine in this order.
Jpn J Exp Med 1988 Dec
PMID:Experimental urolithiasis in the bladder of rats. 307 86

Ingestion of large amounts of ammonium increases markedly the content of tubulin in brain. The effect on tubulin induction of ammonium ingestion for up to 100 days was investigated. Brain tubulin content showed a rapid initial increase (28%) at 2 days and reached 50% after 100 days on the diet. To discern if ammonia, the increase in urea synthesis, or both was responsible for tubulin induction, rats were maintained at several levels of uremia (by administering diets containing 0 to 80% protein) or in hyperammonemia (by urease treatment). Only ammonium administration in the diet and urease injection induced tubulin in brain. Tubulin was quantified in three different brain regions. There was a regional selectivity of tubulin induction by ammonia in rat brain. Whereas the cerebellum remained unaltered, the paleencephalon showed the highest increase, and the cerebral cortex exhibited only a modest increase.
J Neurochem 1988 Dec
PMID:High ammonia levels in brain induce tubulin in cerebrum but not in cerebellum. 318 62

Jack bean urease is a proteinaceous enzyme, MW approximately 489 kD, readily soluble in water but losing activity when sheared in solution at stresses as low as 2.5 Pa. There is a need for controlled-release forms of many of the new genetically engineered peptide and polypeptide drugs with high specific activities. The simplest form of controlled release would be a sterile compressed pellet of the active component inserted subdermally. However, "activity" may be lost on compaction. Urease can be regarded as a model protein which may lose activity when sheared during compaction in the dry state. Tablets of urease weighing 100 mg were compressed over a range of pressures from 60 to 1750 MPa. No relative loss of activity would be detected following compaction at pressures up to 474 MPa. Above this limiting pressure there was a 50% loss of relative activity, evidently by a compactional effect on the protein quaternary and tertiary structures. No direct relationship was observed between stress (compactional pressure) and inactivation.
Pharm Res 1988 Dec
PMID:The effect of compactional pressure on urease activity. 324 88

In a prospective study, three antral biopsies were taken from 175 dyspeptic patients during routine endoscopy. One biopsy was inserted immediately into a gel-containing well of a CLOtest slide and two biopsies were sent to histopathology. Using the CLOtest, 84 of the 175 samples (48%) detected urease activity in the gastric biopsy, suggesting infection with Campylobacter pylori. Histopathological examination by two independent observers reported that 93 (52%) of the biopsies contained Campylobacter-like organisms. The CLOtest was found to have a specificity of 1.0 and sensitivity of 0.91, providing a rapid identification of most patients harbouring the organism in their gastric mucus.
Postgrad Med J 1988 Dec
PMID:Rapid urease test provides specific identification of Campylobacter pylori in antral mucosal biopsies. 325 8

Ten strains of Proteus penneri isolated from geographically diverse laboratories were tested for urease activity. Cell lysates from urea-induced cells had a mean activity of 4.9 +/- 4.1 mumol of NH3 per min per mg of protein. On nondenaturing 6% polyacrylamide activity gels, the enzymes of P. penneri had very similar electrophoretic mobilities within species and within the Proteus genus but were distinct from the ureases of Providencia and Morganella species. On lower-percentage polyacrylamide, differences in mobilities of the ureases could be detected between the Proteus species. From representative strains, the P. penneri urease was found to be inducible by growth in urea and had an apparent molecular weight of 246,000 +/- 9,000, an isoelectric point of 5.1, and a Km for urea of 14 mM and was inhibitable by acetohydroxamic acid, hydroxyurea, and EDTA. In an in vitro model of struvite formation, a P. penneri strain produced abundant crystals on a glass rod submerged in synthetic urine in the absence but not presence of acetohydroxamic acid (500 micrograms/ml).
J Clin Microbiol 1987 Dec
PMID:Urease activity of Proteus penneri. 342 22

Cat leprosy bacilli passaged in mice could be isolated on 1% Ogawa yolk medium. The isolated cat leprosy bacilli which were cultivated successively four times on 1% Ogawa yolk medium produced a leproma in mice. All characteristics of the isolated cat leprosy bacillus were the same as isolated murine leprosy bacillus, as follows: slow grower, light yellowish-white rough colony, production of much coproporphyrin on the medium, heat-resistant catalase negative, heat-resistant phosphatase negative, arylsulfatase negative, niacin negative, hydrolysis of Tween 80 negative, urease negative, nicotinamidase positive, pyrazinamidase positive, cytochrome b1 at 560 nm positive, cytochrome a2 at 630 nm positive, and cytochrome c at 550 nm negative. Cats are susceptible to both cat and murine leprosy bacilli; the bacilli produced a leproma in a newborn cat at 3 to 4 months and in an adult cat at 2 months after inoculation. Many globi of acid-fast bacilli (AFB) were observed in the histopathological sections and the smear preparations of the newborn cat's lepromas, especially in the necrotic areas of the lepromas. Many AFB and polymorphonuclear leukocytes were seen in the histopathological sections and the smear preparations of the adult cat's lepromas. These lepromas formed ulcers by autolysis and healed or absorbed without ulcer formation over the course of months. Large lepromas remained for a long time without ulcer formation and caseation in some cats. Secondary infections with cat and murine leprosy bacilli were done respectively to the right and left femoral subcutaneous regions of newborn cats carrying primary lepromas. After one month, granulomas in which many AFB were observed were produced in both infection sites. Cats are susceptible to infection with cat and murine leprosy bacilli; however, the bacilli did not invade progressively to internal organs or other subcutaneous areas. Cat leprosy bacilli which were passaged in the mouse are identical to murine leprosy bacilli.
Int J Lepr Other Mycobact Dis 1986 Dec
PMID:Identification of cat leprosy bacillus grown in mice. 354 48

Antisuppressor mutations reduce the efficiency of nonsense suppressors. A mutation in the gene sin4 of Schizosaccharomyces pombe leads to loss of 5-(methoxycarbonylmethyl) thiouridine (mcm5s2U) from the first anticodon position of tRNAs. This resembles the phenotype of sin3 (Heyer, W. D., Thuriaux, P., Kohli, J., Ebert, P., Kersten, H., Gehrke, C., Kuo, K. C., and Agris, P. F. (1984) J. Biol. Chem. 259, 2856-2862), but the mutations reside in different genes. In vivo 35S-labeled tRNA from the parental suppressor strain sup3, the antisuppressor strains sin3 and sin4, and the double mutant sin3 sin4 has been digested to nucleosides and analyzed with high performance liquid chromatography methods. The major sulfur-carrying nucleoside in wild-type S. pombe tRNA is mcm5s2U. It is reduced in the mutant strains. Two other thiolated nucleosides are also present: 2-thiouridine and a nucleoside of unknown structure. Neither was affected by the antisuppressor mutations. Thiocytidine has not been found. Independent from their effect on suppressors, the two mutations sin3 and sin4 reduce the growth rate of cells, and sin3 also increases cell length. In vivo decoding of the serine codon UCG by the UCA reading serine tRNA is not promoted by the two antisuppressor mutations.
J Biol Chem 1986 Dec 15
PMID:Antisuppressor mutations and sulfur-carrying nucleosides in transfer RNAs of Schizosaccharomyces pombe. 378 24


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