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

---

Query: EC:6.3.4.6 (urease)
7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In accordance with Recommendation 30b of the International Code of Nomenclature of Bacteria, which calls for the development of recommended minimal standards for describing new species, we propose minimal standards for describing the genus Mycobacterium and new slowly growing species of this genus. The minimal standards for assignment of a strain to the genus Mycobacterium include acid-alcohol fastness, a DNA G+C content in the range from 61 to 71 mol%, and mycolic acid detection with characterization of C22 to C26 pyrolysis esters. The recommended minimal standards for describing a new slowly growing Mycobacterium species are based on the results of phenotypic and genomic studies and include the results of the following conventional tests: growth at 25, 30, 33, 37, 42, and 45 degrees C; pigmentation; resistance to isoniazid, thiophene-2-carboxylic acid hydrazide, hydroxylamine, p-nitrobenzoic acid, sodium chloride, thiacetazone, picrate, and oleate; catalase activity; Tween hydrolysis; urease activity; niacin detection; and nitrate reductase, acid phosphatase, arylsulfatase, pyrazinamidase, and alpha-esterase activities. In addition, a mycolic acid profile should be determined, and DNA-DNA hybridization experiments in which the difference between the denaturation temperature of the homologous reaction and the denaturation temperature of the heterologous reaction is determined should be performed. This proposal has been endorsed by the members of the Subcommittee for Taxonomy of the Mycobacteria of the International Committee on Systematic Bacteriology.
...
PMID:Proposed minimal standards for the genus Mycobacterium and for description of new slowly growing Mycobacterium species. 158 Nov 93

The MICRO-ID LISTERIA system, designed to identify Listeria isolates to species level within 24 h, was compared with conventional biochemical identification. MICRO-ID LISTERIA used in combination with the CAMP test correctly identified 409 (98.8%) of 414 strains isolated from human, animal, food, and environmental sources belonging to the seven species currently defined within the genus Listeria. The kit was easy to use and simple to interpret. However, 8 of the 15 tests (i.e., phenylalanine deaminase, hydrogen sulfide, indole, ornithine decarboxylase, lysine decarboxylase, malonate, urease, and o-nitrophenyl-beta-D-galactopyranoside) were considered superfluous for the differentiation of Listeria spp. The CAMP test was indispensable when using the MICRO-ID LISTERIA system, in particular to differentiate CAMP test-positive L. monocytogenes from the nonhemolytic, rhamnose-positive L. innocua. The hemolytic L. seeligeri and L. ivanovii strains and the nonhemolytic, non-rhamnose-acidifying L. welshimeri strains could also be differentiated from one another only on the basis of their CAMP test results. The very few strains of L. grayi and L. murrayi were easily differentiated from the other nonhemolytic species. Catalase-negative cocci should not be tested, because 12 out of 19 catalase-negative strains (all enterococci) in our test were misidentified as Listeria spp. The MICRO-ID LISTERIA system identified strains within 18 to 24 h and is thus less time-consuming than conventional tests. The system could, therefore, be used together with correctly done CAMP tests for the rapid identification of Listeria isolates, especially food and environmental isolates, for which rapid species differentiation is important.
...
PMID:Evaluation of the Organon-Teknika MICRO-ID LISTERIA system. 162 80

Bilophila wadsworthia is an anaerobic, gram-negative, asaccharolytic, bile-resistant, catalase-positive bacillus that is usually urease positive and was originally recognized in specimens of peritoneal fluid and tissue from patients with appendicitis. Additional isolations from clinical specimens, including a scrotal abscess, mandibular osteomyelitis, axillary hidradenitis suppurativa, pleural fluid, joint fluid, and blood, are described here.
...
PMID:Bilophila wadsworthia isolates from clinical specimens. 162 48

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.
...
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

Helicobacter pylori can be considered a very successful organism effectively colonizing the majority of the world's population. Although various disease states associated with this infection have been described, the mechanisms of pathogenicity remain unknown. The easiest virulence factors to identify are those enabling the organism to colonize the hazardous microenvironment of the gastric epithelium, survive at this site, and multiply sufficiently for transmission to a new host. The factors identified to date include the bacterial enzymes urease and catalase, flagella, and lectin-like adhesins. In addition, it is proposed that the organism has evolved mechanisms to avoid the local antibody responses of the host. Several putative virulence factors that could directly cause gastroduodenal damage have also been identified. These include the direct tissue damage by cytotoxins or the products of urease activity and the indirect tissue damage due to disruption of mucin integrity. Such mechanisms may contribute to peptic ulcer formation; however, the chronic superficial gastritis most frequently associated with this infection is probably caused by immunopathologic events mediated by the host in response to the continued antigen load on the gastric mucosa.
...
PMID:Virulence factors of Helicobacter pylori. 177 22

H. pylori is a highly virulent organism as evidenced by its low infective dose and widespread high prevalence in human populations. Its virulence is achieved through its ability to survive in a moist environment and its massive urease production which allows it to survive in the acidic gastric juice long enough to colonize the gastric mucus. Gastric colonization is facilitated by cell wall associated lectins which permit the bacterium to bind to gastric mucus and the gastric epithelial cell. Once in this location, H. pylori produces several enzymes which may harm the gastric epithelium, particularly urease (through ammonia generation) and phospholipases A and C. H. pylori also weakens the gastric mucous layer by digesting its glycoproteins and lipids, making the mucus less hydrophobic and more water soluble. Helicobacter pylori attracts phagocytic cells, inducing both acute and chronic inflammation as well as an antibody response. Persistence of H. pylori in the mucosa may be enhanced by its cytotoxin and catalase production, by which it survives after phagocytosis by neutrophils.
...
PMID:Virulence and pathogenicity of Helicobacter pylori. 191 16

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.
...
PMID:Helicobacter nemestrinae sp. nov., a spiral bacterium found in the stomach of a pigtailed macaque (Macaca nemestrina) 174 3

A mutant strain of Helicobacter pylori with weak urease activity was created by using N-methyl-N'-nitro-N-nitrosoguanidine. The urease activity of the mutant (0.036 +/- 0.009 nmol of urea per micrograms of bacterial protein per min) was 0.4% of that of the parental strain (8.20 +/- 2.30 nmol of urea per micrograms of bacterial protein per min). The mutant was otherwise indistinguishable from the parental strain. Both demonstrated prominent catalase and oxidase activities, and both produced vacuolating cytotoxin. Restriction endonuclease and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns and ultrastructure were identical for the two strains. The mutant was fully motile, as evaluated by spreading in soft agar and by direct microscopic examination. Growth rate and colony size and morphology were identical for the mutant and parental strains. Seventeen gnotobiotic piglets were challenged with either the mutant or the parental strain and sacrificed 3 or 21 days after challenge. Gastric tissue was examined histologically and cultured for H. pylori. Of seven piglets challenged with the parental strain, all became infected. H. pylori was not recovered from any of 10 piglets challenged with the urease-negative strain. Lymphofollicular gastritis was present in all seven piglets challenged with the parental strain but in none of the piglets challenged with the urease-negative strain. These results suggest that prominent urease activity is essential for colonization by H. pylori.
...
PMID:Essential role of urease in pathogenesis of gastritis induced by Helicobacter pylori in gnotobiotic piglets. 205 Apr 11

A biochemical, physiological and enzymatic study of 78 C. pylori strains isolated from gastroduodenal biopsies is reported. All strains were positive in the oxidase, catalase and urease tests. 97.4% produced SH2 in the lead acetate band and 79.4% showed beta-hemolytic activity in sheep blood agar. In the antibiotic selection tests, C. pylori was characterized to be resistant to nalidixic acid and sensitive to cefalotin . The enzymatic study demonstrated the presence of acid and alkaline phosphatases. This finding and the urease test give C. pylori a define bacteriological character which differentiate it from the remaining campylobacteria.
...
PMID:[Biochemical, physiological, and enzymatic study of 78 strains of Helicobacter (Campylobacter) pylori isolated from gastroduodenal biopsies]. 209 88

When leprosy bacilli grown in nude mouse foot pad were used for culture experiments, cultivable acid-fast bacillus was sometimes isolated as a contaminant. Whenever bacilli were inoculated to nude mice, the same leprosy bacilli were killed by autoclaving and were inoculated in to foot pads of 5 nude mice for examination of this cause of the contamination. Acid-fast bacillus was cultivated on 3% Ogawa egg medium at 33 degrees C from homogenates of foot pads of nude mice infected with M. leprae after one year and a while of infection. Foot pad of nude mouse injected with leprosy bacilli was cut off, ground in mortar and passed through sterile absorbent cotton and the filtrate was centrifuged at 10,000 rpm for 30 minutes. The sediment was inoculated on 3% Ogawa egg medium after treating with a small amount of sterile 1 N sodium hydroxide. Acid-fast bacilli were isolated from 3 out of 41 mice inoculoted with heat killed bacilli. The isolated acid-fast bacillus did not be observed in the same experimental group inocudated with live bacilli, positive cases were scattered in another groups. Four out of 16 tubes were positive for acid-fast bacilli in mice infected with Kurume-naha and 5 out of 7 tubes in the Amami-KM infected mouse group. The two negative tubes were discarded due to contamination. Kurume-Oki strain which has yellow colonial morphology was isolated from one out of 6 culture tubes. Strains Kurume-naha and Amami-KM have the same characteristics as follows: slow grower with pale yellow smooth colonial morphology, strongly positive for niacin production and ureas; positive for nicotinamidase, pyradinamidase and 68 degrees C catalase; no growth at 45 degrees C, negative for nitrate reduction, hydrolysis of Tween 80, diamine oxidase, heat stable acid-phosphatase and arylsulphatase; resistant to streptomycin, isoniazid, rifampicin and B 663. Two isolates were identified as Mycobacterium simiae from these characteristics. Characteristics of a Kurume-Oki isolate was as follows: slow grower with yellow smooth colonial morphology, positive for urease, 68 degrees C catalase, hydrolysis of Tween 80 and arylsulfatase; no growth at 45 degrees C, negative for niacin production, nicotinamidase, pyradinamidase, nitrate reduction, daimine oxidase and heat stable acid-phosphatase; resistant to streptomycin, isoniazid, rifampicin and B. 663. This bacillus was identified as Mycobacterium gordonae from these characteristics.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:[Acid-fast bacilli isolated from foot pads of nude mice infected with leprosy bacilli]. 213 33


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---