Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “UREASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,225 records · Page 68Linked to original sources
PubMed2003

The three-dimensional structure of the N-acetylglucosamine-6-phosphate deacetylase, NagA, from Bacillus subtilis: a member of the urease superfamily.

The enzyme N-acetylglucosamine-6-phosphate deacetylase, NagA, catalyzes the hydrolysis of the N-acetyl group of GlcNAc-6-P to yield glucosamine 6-phosphate and acetate, the first committed step in the biosynthetic pathway to amino-sugar-nucleotides. It is classified into carbohydrate esterase family CE-9 (see afmb.cnrs-mrs.fr/CAZY/). Here we report the cloning, expression, and three-dimensional structure (Protein Data Bank code 1un7) determination by x-ray crystallography of the Bacillus subtilis NagA at a resolution of 2.0 A. The structure presents two domains, a (beta/alpha)(8) barrel enclosing the active center and a small beta barrel domain. The structure is dimeric, and the substrate phosphate coordination at the active center is provided by an Arg/His pair contributed from the second molecule of the dimer. Both the overall structure and the active center bear a striking similarity to the urease superfamily with two metals involved in substrate binding and catalysis. PIXE (Proton-Induced x-ray Emission) data show that iron is the predominant metal in the purified protein. We propose a catalytic mechanism involving proton donation to the leaving group by aspartate, nucleophilic attack by an Fe-bridged hydroxide, and stabilization of the carbonyl oxygen by one of the two Fe atoms of the pair. We believe that this is the first sugar deacetylase to utilize this fold and catalytic mechanism.

Amidohydrolases↗
PubMed2006

First restriction and genetic mapping of the genomic DNA of urease-positive thermophilic campylobacters (UPTC), and small restriction fragment sequencing.

A restriction and genetic map of urease-positive thermophilic campylobacter (UPTC) CF89-12 genome DNA is constructed using a pulsed-field gel electrophoresis procedure after digestion with SalI and SmaI and Southern blot hybridisation. Each of the six gene fragments (flaA, glyA, lysS, recA, sodB and ureAB) selected are mapped in only a fragment on the restriction map. Three DNA fragments for rrn operon probes are mapped in multiple regions on the map. When two SmaI-digested neighbouring small fragments hybridised with rrn probes are cloned and sequenced, a total sequence length of 7487 bp is determined. In the sequence, part of the pnp gene (734 bp) bearing a p-independent transcriptional termination region, a cluster of five tRNA genes including the putative promoter region, a hypothetical Cj0171-like 507-bp sequence containing an internal termination codon, and a part of the rrn operon including the putative promoter region (4700 bp) are identified. The 507 bp sequence carried both putative transcriptional promoter sequences, including a ribosome binding site upstream of the ATG start codon and a characteristic G9 structure, and a possible p-independent transcriptional termination region. A hypothetical Cj0170-like 204-bp sequence containing an internal termination codon also occurred, overlapping partly with the Cj0171-like sequence. Based on nucleotide sequence alignment analysis between the UPTC rrn operon examined here and the previously reported one, two different 16S-23S ribosomal DNA (rDNA) internal spacer regions are shown to exist.

Base Sequence↗
PubMed1974

Growth of T-strain mycoplasmas in medium without added urea: effect of trace amounts of urea and of a urease inhibitor.

Urea is currently considered to be a requirement for the propagation of T-strain mycoplasmas. We report here the replication of T-strain 960 (ATCC 25023) in media prepared from dialyzed components with added putrescine and allantoin but without added urea, or in dialyzed medium containing small amounts of added urea. The least amount of urea which allowed growth in the medium without allantoin was above 10 mug/ml. The amount of urea estimated to contaminate the added allantoin or putrescine was 5 mug/ml or less, which is insufficient to support T-strain replication. T-strain 960 was grown in the presence of urea and the urease inhibitor acetohydroxamic acid AHA where the organisms multiplied at a slower rate in the presence of AHA than in its absence. Urea hydrolysis occurred with concomitant ammonia accumulation and pH increase in cultures with AHA added.

Allantoin↗
PubMed2000

Helicobacter aurati sp. nov., a urease-positive Helicobacter species cultured from gastrointestinal tissues of Syrian hamsters.

A novel helicobacter with the proposed name Helicobacter aurati (type strain MIT 97-5075c) has been isolated from the inflamed stomachs and ceca of adult Syrian hamsters. The new species is fusiform with multiple bipolar sheathed flagella and periplasmic fibers; it contains urease and gamma-glutamyl transpeptidase. By 16S rRNA sequencing and repetitive element PCR-based DNA fingerprinting, it was found that H. aurati represents a distinct taxon and clusters with Helicobacter muridarum, Helicobacter hepaticus, and Helicobacter sp. MIT 94-022. H. aurati was recovered from hamsters housed in various research and vendor facilities. Further studies are necessary to define its association with disease and other microbiota in hamsters, as well as its impact on research projects involving hamsters. H. aurati (GenBank accession number AF297868) can be used in animal experiments to define the factors that are important for gastric helicobacter pathogenesis.

Animals↗
PubMed1993

Antibacterial action of the urease inhibitor acetohydroxamic acid on Helicobacter pylori.

The urease inhibitor acetohydroxamic acid (AHA) was assessed for its bacteriostatic and bactericidal effects on Helicobacter pylori. For eight isolates of H pylori, the minimum inhibitory concentration (MIC) was either 200 mg/l or 400 mg/l. Interactions between AHA and antimicrobial drugs used to treat H pylori were also determined. For most isolates AHA reduced the MIC for colloidal bismuth subcitrate (CBS), tetracycline, metronidazole, and amoxicillin. In a few isolates, however, AHA increased the minimum bactericidal concentration (MBC) for these antimicrobial treatments. In vitro AHA is active against H pylori and it interacts with other agents directed against H pylori.

Amoxicillin↗
PubMed2004

Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter found in free-flying peregrine falcons (Falco peregrinus) in Sweden.

Rare species with small population sizes are vulnerable to perturbations such as disease, inbreeding, or random events. The threat arising from microbial pathogens could be large and other species could act as reservoirs for pathogens. We report finding three enteric bacterial species, Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter, in nestling free-flying peregrine falcons (Falco peregrinus) in Sweden in 2000. Campylobacter jejuni isolates exhibited marked genetic similarities to an isolate from a human, providing a possible association between a human-associated strain of this bacterium and peregrine falcons.

Animals↗
PubMed1977

Recovery of Chlamydia and Genital Mycoplasma transported in sucrose phosphate buffer and urease color test medium.

Urethral swabs from 75 males with urethritis were extracted into tryptose phosphate broth and then equal aliquots were dispensed into vials containing sucrose phosphate buffer (2SP) and urease color test medium (U-9). No antibiotics were present in the media. After transport to the laboratory, the recovery of Chlamydia trachomatis and Ureaplasma urealyticum was evaluated after inoculation into McCoy's cell cultures and agar medium, respectively. C. trachomatis was recovered from significantly more patients (17 versus 12, P = 0.03) with higher inclusion counts (P less than 0.01) in specimens transported in 2SP as compared with those in U-9 medium. No significant differences between the isolation rate of U. urealyticum and that of Mycoplasma hominis were found with the two media. The rate of inactivation of C. trachomatis and U. realyticum at 4 C was examined by means of reference strains. The inactivation of C. trachomatis was similar in both 2SP and U-9 media, but the number of inclusions was consistently greater in the 2SP medium. In contrast, the number of colony-forming units of U. urealyticum actually increased over a 24-hour period in both media. We conclude that 2SP is the best medium for the combined recovery of C. trachomatis and genital Mycoplasma. The use of one transport medium and hence a single swab culture has the obvious advantages of saving time and expense for both physician and laboratory, and for the patient it will eliminate the possible discomfort of having multiple cultures taken.

Bacteriological Techniques↗
PubMed1998

Luminometric single step urea assay using ATP-hydrolyzing urease.

An automatic enzyme kinetic luminometric method for determination of small quantities of urea in biological fluids and in microdialysates is presented. The method is based on the ATP-hydrolyzing urease reaction [urea amidohydrolase (ATP-hydrolyzing); EC 3.5.1.45], monitored by a luciferin-luciferase ATP reaction. The assay range is 100 pmol to 50 nmol with a detection limit of 5 micromol/L in the sample, compared with detection limits of 0.1 mmol/L in earlier spectrophotometric methods. To reduce the non-urea-dependent ATPase activity (v(blank)) and to increase the urea-dependent activity, 1,2-propanediol was included. Assay conditions were optimized by multivariate analysis. Recoveries of urea added to blood dialysate and plasma were 96-103%. No analytical interference of common metabolites, drugs, or other additives was observed. The total CVs (6 days and six concentrations, 1.2-21.8 mmol/L) were 3.6-8.5%. The results obtained with the present assay were highly correlated for dialysate (r = 0.979) and for plasma (r = 0.978) with those obtained by a spectrophotometric kit method with slopes of 1.02-1.03 and intercepts of 0.08-0.23 mmol/L.

Adenosine Triphosphate↗