Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.5 (urease)
 7,257 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastric cancer is the world's overall second most common cancer, and carries a bad prognosis. In the Correa model of gastric carcinogenesis, environmental factors (salt, nitrate, a lack of vitamin C and beta-carotene, bile reflux, bacterial overgrowth in atrophic gastritis with nitrosamine formation) are related to the evolution from normal gastric tissue through superficial gastritis, multifocal atrophic gastritis, intestinal metaplasia and dysplasia to carcinoma. The incidence of H. pylori decreases with progressing preneoplastic lesions. In several studies, the prevalence of H. pylori was elevated in patients with gastric cancer, with a trend for a higher prevalence in intestinal type gastric cancer vs diffuse type. Family members of patients with gastric adenocarcinoma have a higher H. pylori prevalence than controls; patients infected with H. pylori have more family members with gastric cancer. Several epidemiological studies showed a higher H. pylori prevalence in regions or populations with high gastric cancer risk vs low-risk populations. Large-scale studies in China and Europe showed a correlation between H. pylori seroprevalence and gastric cancer incidence and mortality. Three prospective nested case-control studies showed that infection with H. pylori increased the risk of further development of gastric adenocarcinoma, showing that H. pylori infection precedes the development of gastric cancer. Several pathways can be identified explaining the association between H. pylori and gastric adenocarcinoma. We showed that gastric cell proliferation is increased in parallel with inflammation. The ascorbic acid concentrating mechanism is abolished in gastritis. Ammonia, generated by H. pylori's urease, gives rise to gastric mucosal atrophy. We showed that salt increases the gastric cell proliferation only in H. pylori-infected individuals. The organism's toxin may play a role in gastric cancer. Besides H. pylori, other environmental factors are important in determining the gastric cancer risk. For instance, we showed that in Belgium, Maghreb immigrants have a high prevalence of H. pylori infection but a low prevalence of intestinal metaplasia and gastric cancer. Gastric lymphoma is rare (about 5% of all gastric tumours), but its incidence is steadily increasing. It was shown that H. pylori also increases the risk for low-grade as well as high-grade gastric lymphoma. Eradication of H. pylori has been shown to cure several cases of unequivocally proven gastric low-grade lymphoma.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Helicobacter pylori: the link with gastric cancer. 806 90

An organism that seems to be identical to Orskov's 'Sarcina mirabilis' [Orskov, J. (1930) Acta Pathol Microbiol Scand Suppl III, 519-541] has been rediscovered in specimens from the upper respiratory tract of humans. Six strains were studied, and the results, which conformed to Orskov's description of S. mirabilis, were as follows. Rough to smooth colonies grow on many plated media and show extremely polymorphic cell morphology with round cells with diameters from 1 to > 10 microns. The smallest cells were often motile with circular movements. Strains were Gram-negative, facultatively anaerobic, oxidase and urease positive, and weakly catalase positive. Nitrate and nitrite were reduced, and glucose, fructose, sucrose and mannitol were fermented. Polysaccharide was produced on sucrose agar. Electron microscopy showed coccoid cells with a bundle of three to nine flagella, a Gram-negative cell-wall morphology, and aggregates of irregular cells held together by a common surface layer. The mean mol% (G+C) of the organisms was 65.0. 16S-ribosomal RNA sequencing revealed that the organism belongs to the beta subgroup of Proteobacteria, separate from all other described genera, but most closely related to Burkholderia. The name Lautropia mirabilis is proposed for this organism.
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PMID:Lautropia mirabilis gen. nov., sp. nov., a gram-negative motile coccus with unusual morphology isolated from the human mouth. 807 12

Urease was purified (4126-fold) from Aspergillus niger (NRRL 003) to a homologous enzyme preparation with a specific activity of 1341 mumol min-1 (mg protein)-1. One species of urease was detected in A. niger, with Km = 3.0 mM, native molecular mass 250,000 Da, pH optimum of 8.0 and a high specificity for urea. Hydroxyurea was a strong competitive inhibitor of urease activity, while N-methylurea acted as a weak uncompetitive inhibitor, based on Lineweaver-Burk and Eadie-Hoftstee plots. The activity of urease was enhanced by, but not dependent on, the presence of Na2EDTA, DL-dithiothreitol (< or = 0.1 to 5.0 mM), Ca2+, Ba2+ and citrate (2 to 20 mM). Urease activity was not affected by Na+, K+, Cl-, Br-, acetate or nitrate (2 to 20 mM), but was significantly decreased in the presence of Li+, Ni2+, Mg2+, Zn2+ or I-. Urease activity decreased 26.0% after 30 min at 65 degrees C, and 86.5% and 100.0% after 5 and 1 min at 80 and 100 degrees C, respectively. Urease activity decreased 30.5% after 90 d at 4 degrees C and 21.0% after 28 d at -20 or -80 degrees C.
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PMID:Isolation and characterization of urease from Aspergillus niger. 833 11

Fourteen human periodontal isolates recovered from a purported Eikenella corrodens-selective medium containing 1 microgram of clindamycin per ml displayed biochemical traits which differed from those described for E. corrodens. These organisms were gram-negative rods which corroded agar. The isolates were oxidase positive and urease, indole, and esculin negative. They differed from E. corrodens in catalase, nitrate reduction, lysine decarboxylase, and ornithine decarboxylase activities. One isolate, strain UB-294, was presumptively identified as Kingella denitrificans. A second isolate, strain UB-204, differed from E. corrodens by being catalase positive and nitrate reduction negative. Twelve isolates, including strain UB-38T (T = type strain), were phenotypically similar to Kingella kingae except that they did not produce acid from maltose and were not beta-hemolytic. Essentially complete (1,480-base) 16S rRNA sequences were determined for strains UB-38T, UB-204, and UB-294 and the type strains of Neisseria animalis, Neisseria canis, Neisseria denitrificans, Neisseria elongata, Neisseria flavescens, Neisseria macaca, and Neisseria polysaccharea. These sequences were compared with the previously published sequences of six other species belonging to the family Neisseriaceae. On the basis of the results of the comparative sequence analysis, UB-294 was confirmed as a K. denitrificans strain, UB-204 was identified as a member of a new species which may belong in the genus Eikenella, and UB-38T was identified as a member of a new species of the genus Kingella, for which we propose the name Kingella oralis [corrected]. Since strain UB-204 was the only representative of a new species, it was not named.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phylogeny of species in the family Neisseriaceae isolated from human dental plaque and description of Kingella oralis sp. nov [corrected]. 834 9

Four strains of a novel Helicobacter species were isolated from the stomachs of cheetahs (Acinonyx jubilatus) with gastritis. These isolates were phenotypically similar to Helicobacter pylori. The isolates were gram-negative, spiral bacteria which grew under microaerophilic conditions at 37 degrees C, but not at 25 or 42 degrees C, and produced urease, catalase, oxidase, alkaline phosphatase, and gamma-glutamyl transpeptidase. The isolates did not ferment glucose, mannitol, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin, or arabinose; hydrolyze hippurate or indoxyl acetate; or reduce nitrate. They did not produce H2S from triple sugar iron agar, and they did not grow in the presence of 1.0% glycine or 1.5% NaCl. They were resistant to nalidixic acid and sensitive to cephalothin and metronidazole. Cells were typically 0.3 by 2.0 microns and possessed tufts of two to five sheathed, monopolar flagella. The G+C content of strain 90-119 was 30 mol%. Cluster analysis of densitometry scans of polyacrylamide protein gels revealed more than 70% similarity of the cheetah isolates to H. pylori, less than 60% similarity to Helicobacter felis, and less than 50% similarity to Helicobacter mustelae. Complete 16S rRNA sequences were determined for two of the cheetah isolates. Phylogenetic analysis was performed by comparing the cheetah sequences to those of 19 reference strains, including H. pylori, H. felis (two strains), H. mustelae, Helicobacter muridarum, "Flexispira rappini," Wolinella succinogenes, Campylobacter coli, Campylobacter concisus, Campylobacter curvus, Campylobacter fetus, Campylobacter hyointestinalis, Campylobacter jejuni, Campylobacter lari, Campylobacter rectus, Campylobacter sputorum subsp. bubulus, a Campylobacter sp. (pig isolate), [Bacteroides] gracilis, and [Bacteroides] ureolyticus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Helicobacter acinonyx sp. nov., isolated from cheetahs with gastritis. 837 70

Fourteen Legionella-like strains isolated from aquatic sources have been characterized serologically, biochemically, and in terms of DNA relatedness. The strains grew on buffered charcoal-yeast extract agar but not on blood agar and displayed phenotypic characteristics typical of the family Legionellaceae, including a requirement for cysteine, cellular fatty acid compositions in which branched-chain acids predominate, and the possession of isoprenoid quinones of the ubiquinone series with more than 10 isoprene units in their side chains. All were nonfermentative, lacked urease, were incapable of nitrate reduction, and reacted positively with a DNA probe specific for the Legionellaceae. DNA hybridization studies in which the hydroxyapatite method was used demonstrated that the strains represented five new species of the genus Legionella. Nine of the strains were more than 90% interrelated, and the name Legionella londiniensis sp. nov. is proposed for this group. Two strains formed a second hybridization group, for which the name Legionella nautarum sp. nov. is proposed, while the three remaining species, Legionella geestiana sp. nov., Legionella quateirensis sp. nov., and Legionella worsleiensis sp. nov., are each represented by a single strain. The levels of relatedness of the new species to each other are 23% or less, and the levels of relatedness to other members of the genus ranged from 0 to 36%. L. geestiana, L. nautarum, and L. londiniensis are serologically unrelated to all other known Legionella species. L. worsleiensis cannot be separated from Legionella pneumophila serogroup 4 by serological methods and is also serologically indistinguishable from L. quateirensis; distinctions may be made on the basis of fatty acid composition and biochemical reactions.
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PMID:Five new Legionella species isolated from water. 849 43

Campylobacter gracilis (formerly Bacteroides gracilis) is an asaccharolytic, nitrate-positive, urease-negative organism that requires formate and fumarate or hydrogen as a growth additive and may pit agar media. Clinical isolates that were obtained primarily from appendiceal and peritoneal fluid specimens and initially were identified in our laboratory as B. gracilis were later found to include "unusual" strains that could be distinguished by biochemical and genetic criteria. These unusual C. gracilis strains were bile resistant, could not reduce tetrazolium chloride under aerobic conditions if formate and fumarate were added to the medium, and could grow in the presence of 2 or 6% oxygen if no blood was added to the medium. C. gracilis, other campylobacters, and the unusual strains produced distinctive dehydrogenase patterns when gels were incubated anaerobically. A cellular fatty acid analysis revealed that the cluster formed by the unusual organisms was distinct from the (separate) clusters formed by C. gracilis, Bacteroides ureolyticus, and other Campylobacter species. 16S rRNA sequence data indicated that these organisms are not related phylogenetically to either C. gracilis or other Campylobacter species; the most closely related taxa as determined by rRNA sequence analysis were unrelated aerobes (members of the genera Bordetella, Alcaligenes, Rhodocyclus, and Comamonas). DNA homology data confirmed that these taxa are separate groups. Our data indicate that the unusual organisms are members of a new genus and new species, for which we propose the name Sutterella wadsworthensis. The type strain of S. wadsworthensis is strain WAL 9799 (= ATCC 51579).
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PMID:Sutterella wadsworthensis gen. nov., sp. nov., bile-resistant microaerophilic Campylobacter gracilis-like clinical isolates. 857 4

An identification scheme for aerobically growing Gram-positive rods (genera Actinomyces, Arcanobacterium, Aureobacterium, Bacillus, Brevibacterium, Cellulomonas, Corynebacterium, Dermabacter, Erysipelothrix, Gardnerella, Lactobacillus, Listeria, Microbacterium, Oerskovia, Propionibacterium, Rhodococcus, Rothia, Turicella, as well as unnamed CDC groups, Clostridium tertium, and Mycobacterium fortuitum/chelonae) is presented. It is derived from the Hollis-Weaver scheme and uses catalase, oxidative/fermentative carbohydrate metabolism and motility as primary reactions. Tests for lipophilism, nitrate reduction, urease, esculin hydrolysis, the CAMP reaction, acid formation from five carbohydrates, as well as for some facultative reactions should lead to a correct diagnosis based on information available at the end of 1995.
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PMID:An identification scheme for rapidly and aerobically growing gram-positive rods. 883 85

Corynebacterium pseudotuberculosis has been classified into two biotypes according to ability to breakdown nitrate (Biberstein et al., 1971). Restriction enzyme analysis (REA) has shown to reflect this differentiation, but numerous bands generated by this technique make interpretation difficult (Songer et al., 1988). Restriction fragment length polymorphism's (RFLP's) has become an accepted genetic tool and was used in this study to determine if differences in nitrate reduction and other phenotypic characteristics could be identified genetically. Thirteen C. pseudotuberculosis isolates from four species of domestic animals from different parts of the world were investigated for phenotypic and genetic differences. Three closely related bacteria, Corynebacterium ulcerans, Actinomyces pyogenes (previously C. pyogenes),and Rhodococcus equi (previously C. equi) were included in the study to determine if the RFLP bands were unique to C. pseudotuberculosis. All C. pseudotuberculosis isolates were positive for urease production. Some differences in maltose and sucrose fermentation ability and nitrate reduction were recorded. Genetic differences were identified between the nitrate-positive group and the nitrate-negative group using non-radioactive ribosomal RNA (rRNA) probes Southern blotted to restriction digests of ApaI, PstI, and SstI. A small number of bands were seen, with distinct differences between the nitrate-positive and the nitrate-negative strains. No genetic variations were seen between strains which reflected differences in carbohydrate fermentation. Strains isolated from different animal species and from different parts of the world could not be differentiated genetically using these three restriction enzymes.
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PMID:Genetic differences between nitrate-negative and nitrate-positive C. pseudotuberculosis strains using restriction fragment length polymorphisms. 886 38

On the basis of biochemical, phenotypic, and 16S rRNA analysis, a novel gram-negative bacterium, isolated from normal and diarrheic dogs as well as humans with gastroenteritis, has been recently named Helicobacter canis. A 2-month-old female crossbred puppy was submitted to necropsy with a history of weakness and vomiting for several hours prior to death. The liver had multiple and slightly irregular yellowish foci up to 1.5 cm in diameter. Histologically, the liver parenchyma contained randomly distributed, occasionally coalescing hepatocellular necrosis, often accompanied by large numbers of mononuclear cells and neutrophils. Sections of liver stained by the Warthin-Starry silver impregnation technique revealed spiral- to curve-shaped bacteria predominantly located in bile canaliculi and occasionally in bile ducts. Aerobic culture of liver was negative, whereas small colonies were noted on Campylobacter selective media after 5 days of microaerobic incubation. The bacteria were gram negative and oxidase positive but catalase, urease, and indoxyl acetate negative; nitrate was not reduced to nitrite, and the organism did not hydrolyze hippurate. The bacteria were also resistant to 1.5% bile. Electron microscopy revealed spiral-shaped bacteria with bipolar sheathed flagella. By 16S rRNA analysis, the organism was determined to be H. canis. This is the first observation of H. canis in active hepatitis in a dog and correlates with recent findings of Helicobacter hepaticus- and Helicobacter bilis-related hepatic disease in mice. Further studies are clearly warranted to ascertain whether H. canis-associated hepatitis is more widespread in canines as well as a cause of previously classified idiopathic liver disease in humans.
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PMID:Helicobacter canis isolated from a dog liver with multifocal necrotizing hepatitis. 888 May 4


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