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)

Bacterial urease, particularly from Proteus mirabilis, has been implicated as a contributing factor in the formation of urinary and kidney stones, obstruction of urinary catheters, and pyelonephritis. Weekly urine specimens (n = 1,135) from 32 patients, residing at two chronic-care facilities, with urinary catheters in place for greater than or equal to 30 days yielded 5,088 phenotypically and serotypically diverse bacterial isolates at greater than or equal to 10(5) CFU/ml. A total of 86% of specimens contained at least one urease-positive species, and 46% of 3,939 gram-negative bacilli were urease positive. For investigation of genetic relatedness of urease determinants, whole-cell DNA from 50 urease-positive isolates each of Providencia stuartii, Providencia rettgeri, P. mirabilis, Proteus vulgaris, and Morganella morganii were hybridized with a urease gene probe derived from within the urease operon of Providencia stuartii BE2467. The percentage of strains hybridizing with the gene probe was 98 for Providencia stuartii, 100 for Providencia rettgeri, 70 for P. mirabilis, 2 for M. morganii, and 0 for P. vulgaris. Electrophoretic mobilities of ureases from representative isolates revealed nine different patterns among the five species. The urease gene probe hybridized with fragments of HindIII-digested chromosomal DNA from all isolates except M. morganii. Fragment sizes differed between species. Molecular sizes of the enzymes, determined by Sephacryl S-300 chromatography, were found to be 280 kilodaltons (kDa) (P. mirabilis), 323 to 337 kDa (Providencia stuartii, Providencia rettgeri, P. mirabilis, P. vulgaris), 620 kDa (providencia rettgeri), and greater than 700 kDa (M. morganii, Providencia rettgeri). Kms ranged from 0.7 mM urea for M. morganii to 60 mM urea for a P. mirabilis isolate. In general, P. mirabilis ureases demonstrated lower affinities for substrate but hydrolyzed urea at rates 6- to 25-fold faster than did enzymes from other species, which may explain the frequent association of this species with stone formation.
Infect Immun 1987 Sep
PMID:Genetic and biochemical diversity of ureases of Proteus, Providencia, and Morganella species isolated from urinary tract infection. 362 98

Campylobacter pylori (C. pyloridis) is a fastidious organism found in the gastric mucosa associated with histological gastritis and peptic ulceration. A rapid identification scheme that detects the presence of preformed enzymes (Rosco Diagnostica, Taastrup, Denmark) was applied to clinical isolates of C. pylori. The isolates tested were a very homogeneous group. They all produced oxidase, catalase, urease, alkaline phosphatase, gamma-glutamyl aminopeptidase, leucine aminopeptidase, and DNase. None produced any of 44 other enzymes tested. No other campylobacter strains produced gamma-glutamyl aminopeptidase, except the six strains of Campylobacter jejuni biotype 2. Different results were obtained with similar substrates produced by other manufacturers, probably due to small substrate differences. These tests are useful for the rapid identification of C. pylori but would be unhelpful in any biotyping scheme. They can also be used to help differentiate other groups within the genus Campylobacter.
J Clin Microbiol 1987 Sep
PMID:Rapid identification of Campylobacter pylori (C. pyloridis) by preformed enzymes. 365 41

Undiluted human urine and synthetic urine were inoculated with urease. No inhibitory activity against urease enzymatic activity could be detected in human urine. The urease-induced crystallization of both calcium phosphate and magnesium ammonium phosphate differed markedly, however, between the individuals studied, and it was less pronounced in human urine than in synthetic urine. This supports the observation made in experiments using diluted urine that human urine possesses an inhibitory activity against urease-induced crystallization and suggests that it has a large interindividual variation.
J Urol 1986 Sep
PMID:The effects of urease in undiluted human urine. 373 63

In vitro tests with the urease inhibitor flurofamide demonstrated that the final inhibitory concentration of 0.5-4 microM on the growth of nine ureaplasma strains was largely ureaplasmastatic, requiring prolonged incubation to have a ureaplasmacidal effect. Intramuscular injection of flurofamide successfully eliminated genital infections of ureaplasma in sheep only when the treatment was repeated on two consecutive days. A dose rate of 5-20 mg/kg body weight eliminated the organism from naturally infected sheep, but 15-25 mg/kg body weight was required to eliminate the infection from eleven of fourteen experimentally, newly infected sheep. Administration of the flurofamide orally in the drinking water failed to eliminate ureaplasmas from any of twenty newly infected sheep.
J Vet Pharmacol Ther 1986 Sep
PMID:Investigation into the inhibitory effect of flurofamide on animal ureaplasmas and its use in the treatment of ureaplasma-infected sheep. 376 18

A rapid, simple and inexpensive procedure for the determination of urease activity by using a thermal conductivity gas chromatography method is presented. The procedure is based on the determination of CO2 released in the urease reaction, and showed low coefficient of variation (c.v. less than 1%) and high sensitivity (detection limit 10(-12) mol). This procedure is also suitable for determination of other decarboxylating enzyme activities.
J Biochem Biophys Methods 1986 Sep
PMID:Determination of urease activity by thermal conductivity gas chromatography. 377 25

A ureolytic strain of Proteus mirabilis, isolated from a patient with infectious kidney stones, produced struvite (MgNH4PO4 X 6 H2O) and apatite [Ca10(PO4)6CO3] crystals in vitro when grown in artificial urine. Surface-attached crystals were encased in a slime-like layer. Scanning electron microscopy revealed that surfaces submerged in the artificial urine were colonized by P. mirabilis. Bacteria-associated crystals appeared soon after colonization and eventually became coated with an amorphous substance. Energy-dispersive X-ray analysis of these crystals revealed the presence of Mg, Ca, and P which are major components of struvite and apatite. Transmission electron microscopy of surface scrapings revealed that the glycocalyx of P. mirabilis contained a large number of crystals. Based on these observations and previous work, a theory for infectious renal calculogenesis is proposed. The kidney is initially colonized by invading ureolytic pathogens. These pathogens secrete copious amounts of glycocalyx which facilitates adhesion of the organisms to the kidney, provides protection for these bacteria, and serves to bind struvite and apatite crystals that result from bacterial urease activity. Growth of these calcified microcolonies into mature stones is characterized by continued bacterial growth, incorporation of urinary mucoproteins into the matrix along with bacterial glycocalyx, and a continued deposition of struvite and apatite crystals due to the high pH. The mature stone, in effect, represents an enlarged "fossilized" bacterial microcolony.
Infect Immun 1985 Sep
PMID:An in vitro ultrastructural study of infectious kidney stone genesis. 389 64

In the present study, three cone openings (0.133; 0.106, and 0.080 cm) and three initial moisture content values (9%, 15% and 21%) were used as treatments to evaluate their effects on the protein quality of full-fat soybean flour, extruded in the Brady Crop Cooker. The specific volume, protein and oil contents as well as available lysine content characteristic of the final product, were not affected by the treatments used. Processing temperatures, however, decreased when the initial moisture content of the material was increased. The nitrogen solubility index was affected by the cone opening but not by the moisture content of the material. With respect to the trypsin inhibitors content, the increase in the initial moisture content in soybeans gave conflicting results. At the 21% moisture treatment, the amounts of trypsin inhibitors were higher than those present in the raw material; a similar effect was also observed with urease activity. At the other two moisture contents (9 and 15%) the amounts of trypsin inhibitors and urease activity were decreased by heat treatment, mainly at the 9% moisture level, which were related to the cone opening of the extruder. PER values in rats were influenced by the moisture content and were not affected by the cone opening. Results obtained in the biological assays with chicks, both for weight gain and conversion efficiency, were favored by a decrease in cone opening. Nevertheless, the increase in the moisture content induced a decrease in weight gain at the 5- and 8-week periods, without affecting the conversion efficiency. The effect of consecutive passes of the material through the extruder was also studied. The product obtained with two extrusions presented a good biological value, probably as a consequence of the low values in the trypsin inhibitors and urease activities. When the material was extruded three times, results proved to be poor, due to a reduction to significant low levels of available lysine content--which becomes limiting--, and nitrogen solubility index of the full-fat soybean flour.
Arch Latinoam Nutr 1985 Sep
PMID:Effects of cone opening, initial moisture content and multiple extrusion on the protein quality of extruded soybean using the Brady Crop Cooker. 393 87

The biochemical characteristics of 59 strains of Moraxella urethralis from clinical specimens, primarily from urine and the female genital tract, were studied. The characteristics included (i) the inability to acidify carbohydrate substrates, (ii) the ability to produce phenylalanine deaminase, (iii) the ability to reduce nitrite, (iv) the lack of urease activity, and (v) the ability of most strains to alkalinize citrate. A means of differentiating M. urethralis from Moraxella osloensis and Moraxella phenylpyruvica was determined.
Appl Microbiol 1974 Sep
PMID:Characterization and differentiation of 59 strains of Moraxella urethralis from clinical specimens. 441 57

1. Glucose oxidase (EC 1.1.3.4) and urease (EC 3.5.1.5) were covalently attached through glutaraldehyde to low-molecular-weight nylon powder. 2. Immobilized derivatives of glucose oxidase and urease were prepared by cross-linking the respective enzymes within the matrix of a nylon membrane. 3. An improved process is described for the immobilization of glucose oxidase and urease on the inside surface of partially hydrolysed nylon tube. 4. Automated analytical procedures are described for the determination of glucose with each of the three immobilized glucose oxidase derivatives and for the determination of urea with each of the three immobilized urease derivatives. 5. The efficiencies of the three immobilized enzyme structures as reagents for the automated determination of their substrates were compared.
Biochem J 1972 Sep
PMID:The immobilization of enzymes on nylon structures and their use in automated analysis. 464 9

Gram-nagative organisms were tested with commercially available reagentimpregnated strips (PATHO-TEC). Of the 291 strains, all were tested by using seven paper tests and their conventional counterparts. Excellent correlation was obtained with the oxidase, phenylalanine-deaminase, and Voges-Proskauer tests. Indole tests made on liquid medium cultures also gave complete correlation, but some false-negative results with indole-positive Proteus strains were obtained when growth from solid medium was tested by the strip method. Paper strip urease tests were positive within 2 hr with all Klebsiella and some Serratia, Herellea, and Citrobacter strains as well as with Proteus strains. Approximately 15% of citrate strip test results differed from those of the conventional tests, and reproducibility was poor on retest. The lysine decarboxylase strip test showed a number of discrepancies and posed problems of interpretation and readability. Paper reagent strip methods are simple and convenient and merit further development to increase the specificity of those which depend on pH change up to that achieved with the Voges-Proskauer, oxidase, phenylalanine, and indole methods.
Appl Microbiol 1969 Sep
PMID:Comparative study of the efficacy of seven paper-reagent strips and conventional biochemical tests in identifying gram-negative organisms. 490 7


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