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)

A polymerase chain reaction (PCR) for the specific detection of Helicobacter pylori was developed with a single primer pair derived from the nucleotide sequence of the urease A gene of H. pylori. We achieved specific amplification of a 411-bp DNA fragment in H. pylori. After 35 cycles of amplification, the product could be detected by agarose gel electrophoresis and contained conserved single HinfI and AluI restriction sites. This fragment was amplified in all 50 strains of H. pylori tested, but it was not detected in other bacterial species, showing the PCR assay to be 100% specific. PCR DNA amplification was able to detect as few as 10 H. pylori cells. PCR detected H. pylori in 15 of 23 clinical human gastric biopsy samples, whereas culturing and microscopy detected H. pylori in only 7 of the samples found to be positive by PCR. Additional primer pairs based on the urease genes enabled the detection of H. pylori in paraffin-embedded human gastric biopsy samples. The detection of H. pylori by PCR will enable both retrospective and prospective analyses of clinical samples, elucidating the role of this organism in gastroduodenal disease.
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PMID:Sensitive detection of Helicobacter pylori by using polymerase chain reaction. 173 52

Helicobacter pylori (H. pylori) is a small gram-negative bacillus, recently discovered, found in the stomach of patients with active chronic gastritis and duodenal ulcers. Production of a potent urease has been described as a trait common to all H. pylori so far isolated. To clarify the role of urease in the pathogenic process, as well as to engineer genetic tools useful for the diagnosis of H. pylori, we cloned the genes responsible for urease activity. A genomic library was constructed in Escherichia coli (E. coli) from the chromosomal DNA of the H. pylori strain 85P using a shuttle cosmind vector that we constructed in vitro capable of replicating both in E. coli and Campylobacter jejuni (C. jejuni). The genes responsible for the urease biosynthesis were cloned into E. coli host, then mobilized into C. jejuni where they were expressed. At least six different genes were shown to be required for the expression of the synthesis of an active enzyme; these genes belong to the same cluster and are regulated at the transcriptional level. The two genes encoding the two subunits of the urease enzyme were identified and sequenced; the products of these genes were compared to the other bacterial ureases. The genetic approach allowed to determine the amino-acid sequence of the most immunogenic antigens of H. pylori. In addition, it provides us with genetic tools: a 294-base pairs (bp) DNA fragment internal to one of the urease genes, was shown to be specific of H. pylori strains. This fragment was selectively amplified by polymerase chain reaction (P.C.R.) using two primers designed to target the urease region of all H. pylori isolates present in biological specimen. In addition, P.C.R. followed by direct DNA sequencing of the 294-bp amplified product was shown to be useful to identify and to distinguish between different H. pylori isolates.
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PMID:[Development of genetic and molecular approaches for the diagnosis and study of the pathogenicity of Helicobacter pylori, agent of gastric inflammatory diseases]. 174 19

On the basis of phenotypic characterization and DNA relatedness determinations, the genus Afipia gen. nov., which contains six species, is described. The type species is Afipia felis sp. nov. (the cat scratch disease bacillus). Afipia clevelandensis sp. nov., Afipia broomeae sp. nov., and three unnamed not associated with cat-borne disease. All but one strain (Afipia genospecies 3) were isolated from human wound and respiratory sources. All Afipia species are gram-negative, oxidase-positive, nonfermentative rods in the alpha-2 subgroup of the class Proteobacteria. They are motile by means of a single flagellum. They grow on buffered charcoal-yeast extract agar and nutrient broth, but rarely on MacConkey agar, at 25 and 30 degrees C. They are urease positive; but they are negative in reactions for hemolysis, indole production, H2S production (triple sugar iron agar), gelatin hydrolysis, esculin hydrolysis, and peptonization of litmus milk. They do not produce acid oxidatively from D-glucose, lactose, maltose, or sucrose. The major cell wall fatty acids are 11-methyloctadec-12-enoic (CBr19:1), cis-octadec-11-enoic (C18:1omega7c), and generally, 9,10-methylenehexadecanote and 11,12-methyleneoctadecanoate; and there are only trace amounts of hydroxy acids. The guanineplus-cytosine content is 61.5 to 69 mol%. A. felis is positive for nitrate reduction and is delayed positive for acid production from D-xylose, but it is catalase negative. A. clevelandensis is negative in all of these tests. A. broomeae is weakly positive for catalase production and acid production from D-xylose, but it is negative for nitrate reduction.
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PMID:Proposal of Afipia gen. nov., with Afipia felis sp. nov. (formerly the cat scratch disease bacillus), Afipia clevelandensis sp. nov. (formerly the Cleveland Clinic Foundation strain), Afipia broomeae sp. nov., and three unnamed genospecies. 177 49

The DNA sequence of the urea amidolyase (DUR1,2) gene from S. cerevisiae has been determined. The polypeptide structure deduced from the DNA sequence contains 1,835 amino acid residues and possesses a calculated weight of 201,665 daltons which favorably correlates with that predicted from compositional analysis of purified protein (1,881 amino acid residues and a molecular weight of 203,900). The C-terminal 57 residues of the polypeptide exhibit significant homology with similarly situated sequences found in five other biotin carboxylases whose primary structures have been determined or deduced from protein and DNA sequence data, respectively. Major S1 nuclease protection fragments derived from DUR1,2 RNA-DNA hybrids exhibit apparent termini at positions -140 and -141 upstream of the coding region. The termini of minor protection fragments also occur at eleven other positions as well.
DNA Seq 1991
PMID:The urea amidolyase (DUR1,2) gene of Saccharomyces cerevisiae. 180 34

Two major subspecies of Staphylococcus cohnii, namely S. cohnii subsp. cohnii, from humans, and S. cohnii subsp. urealyticum, from humans and other primates, are described on the basis of a study of 14 to 25 strains and 18 to 33 strains, respectively. DNA-DNA hybridization studies conducted in our laboratory in 1983 (W. E. Kloos and J. F. Wolfshohl, Curr. Microbiol. 8:115-121, 1983) demonstrated that strains representing the different subspecies were significantly divergent. S. cohnii subsp. urealyticum can be distinguished from S. cohnii subsp. cohnii on the basis of its greater colony size; pigmentation; positive urease, beta-glucuronidase, and beta-galactosidase activities; delayed alkaline phosphatase activity; ability to produce acid aerobically from alpha-lactose; and fatty acid profile. The type strain of S. cohnii subsp. cohnii is ATCC 29974, the designated type strain of S. cohnii Schleifer and Kloos 1975b, 55. The type strain of S. cohnii subsp. urealyticum is ATCC 49330.
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PMID:Staphylococcus cohnii subspecies: Staphylococcus cohnii subsp. cohnii subsp. nov. and Staphylococcus cohnii subsp. urealyticum subsp. nov. 185 41

The urease genes from Staphylococcus xylosus C2a, Staphylococcus aureus U500, and S. aureus Newman were cloned in Staphylococcus carnosus using the plasmid vectors pCA43 and pCA44. The resulting respective recombinant plasmids pUra 402, pUraUH66, and pUra17 contained chromosomal DNA fragments with sizes of 5.6, 5.8, and 6.8 kb, respectively. Investigations on urease expression of the donor and recombinant strains in media with various nitrogen sources revealed that S. xylosus C2a produced urease constitutively at the highest specific activity. All of the recombinant strains had significantly lower urease activities than their DNA-donor strains. The nickel-dependence of urease was demonstrated in S. aureus U500 by a plate diffusion assay.
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PMID:Cloning and expression of various staphylococcal genes encoding urease in Staphylococcus carnosus. 188 84

A new subspecies, Staphylococcus capitis subsp. ureolyticus, was isolated from human skin and is described on the basis of studies of 15 to 26 strains. DNA-DNA reassociation reactions demonstrated that these strains were closely related to Staphylococcus capitis but were significantly divergent. The strains of S. capitis subsp. ureolyticus can be distinguished from S. capitis by their positive urease activity, their ability to produce acid from maltose under aerobic conditions, their fatty acid profile, and their colony morphology. The type strain of the new subspecies is strain ATCC 49326.
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PMID:Staphylococcus capitis subsp. ureolyticus subsp. nov. from human skin. 199 30

A new microaerophilic, spirally curved, rod-shaped bacterium was isolated from the gastric mucosa of a pigtailed macaque (Macaca nemestrina). The gram-negative cells of this bacterium are oxidase, catalase, and urease positive and strongly resemble Helicobacter pylori (Campylobacter pylori) cells. Like H. pylori, this organism does not metabolize glucose, does not reduce nitrate or produce indole, does not produce H2S from triple sugar iron agar, does not hydrolyze hippurate or esculin, and does not grow in the presence of 1% glycine, 1.5% salt, or 1% bile. Also like H. pylori, it is resistant to nalidixic acid and susceptible to cephalothin. However, unlike H. pylori, the colorless colonies are flat and have irregular edges. This organism has a unique cellular fatty acid composition, forming a new gas-liquid chromatography group, group K, and a distinctive DNA content (24 mol% guanine plus cytosine). It exhibits less than 10% DNA-DNA homology (as determined by the nylon filter blot method at 65 degrees C) with other members of the genus Helicobacter. Although the levels of DNA relatedness between previously described Helicobacter species and the new organism are low (less than 10%) and the difference in guanine-plus-cytosine content is large (24 versus 36 to 41 mol%), the genus Helicobacter is the only genus in which it is logical to include the organism at this time. We propose that our single strain represents a new species, Helicobacter nemestrinae, and we designate strain T81213-NTB (= ATCC 49396) as the type strain.
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PMID:Helicobacter nemestrinae sp. nov., a spiral bacterium found in the stomach of a pigtailed macaque (Macaca nemestrina) 174 3

Production of a potent urease has been described as a trait common to all Helicobacter pylori so far isolated from humans with gastritis as well as peptic ulceration. The detection of urease activity from genes cloned from H. pylori was made possible by use of a shuttle cosmid vector, allowing replication and movement of cloned DNA sequences in either Escherichia coli or Campylobacter jejuni. With this approach, we cloned a 44-kb portion of H. pylori chromosomal DNA which did not lead to urease activity when introduced into E. coli but permitted, although temporarily, biosynthesis of the urease when transferred by conjugation to C. jejuni. The recombinant cosmid (pILL585) expressing the urease phenotype was mapped and used to subclone an 8.1-kb fragment (pILL590) able to confer the same property to C. jejuni recipient strains. By a series of deletions and subclonings, the urease genes were localized to a 4.2-kb region of DNA and were sequenced by the dideoxy method. Four open reading frames were found, encoding polypeptides with predicted molecular weights of 26,500 (ureA), 61,600 (ureB), 49,200 (ureC), and 15,000 (ureD). The predicted UreA and UreB polypeptides correspond to the two structural subunits of the urease enzyme; they exhibit a high degree of homology with the three structural subunits of Proteus mirabilis (56% exact matches) as well as with the unique structural subunit of jack bean urease (55.5% exact matches). Although the UreD-predicted polypeptide has domains relevant to transmembrane proteins, no precise role could be attributed to this polypeptide or to the UreC polypeptide, which both mapped to a DNA sequence shown to be required to confer urease activity to a C. jejuni recipient strain.
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PMID:Shuttle cloning and nucleotide sequences of Helicobacter pylori genes responsible for urease activity. 200 95

A polymerase chain reaction for the specific detection of Helicobacter pylori was developed using a primer pair derived from the nucleotide sequence of the urease A gene of H pylori. Specific amplification of a 411 base pair DNA fragment from all strains of H pylori tested was achieved. Ten organisms were detected using the PCR and the technique permitted direct detection of H pylori in clinical biopsy samples. PCR will be useful for both prospective and retrospective investigation of the aetiology and epidemiology of H pylori associated disease.
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PMID:Detection and identification of Helicobacter pylori by the polymerase chain reaction. 206 32


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