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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)

Sone strains of Klebsiella pneumoniae and K. oxytoca grown on nutrient agar may appear "urease negative" in a Ferguson type reagent medium after a 24 h incubation at 37 degrees C. Amongst such 147 so called urease negative strains, urease has been detected within a few hours in 79 strains, when bacteria have grown on media containing carbohydrates (Kligler iron agar, Drigalski lactose agar, SS agar and Worfel-Ferguson sucrose medium). Acid production by carbohydrate fermentation increases urease production by Klebsiella: pH 4 is the most convenient pH for urease synthesis by these bacteria. The other 68 strains have been considered as urease-less Klebsiella. The best results are obtained from culture on Worfel-Ferguson sucrose medium: urea hydrolysis is positive--on an average-after 1 hour and 30 minutes when detected in a Ferguson type reagent medium, and after 2 hours and 35 minutes when detected in a Christensen reagent medium.
Ann Microbiol (Paris) 1975 Sep
PMID:[Carbohydrate containing media for the detection of urease in "Klebsiella"]. 0 30

A mass fragmentographic method of high accuracy for determination of serum urea is described. A fixed amount of [15N2]urea is added to a fixed amount of serum, then the urea is converted into 5,5-diallyl barbituric acid by coupling with diallyl malonic acid diethyl ester. The barbiturate is then transferred from an alkaline water phase into an organic phase containing methyl iodine by ion-pair extraction using tetrabutyl ammonium as the positive counterion. The amount of urea is determined from the ratio between the recordings at m/e 236 and m/e 238 obtained after analysis with a combined gas chromatograph-mass spectrometer equipped with an MID-unit (multiple-ion detector). The two ions used correspond to the molecular peak in the mass spectrum of the methyl derivative of unlabeled and labeled 5,5-diallyl barbituric acid, respectively. The relative standard deviation of the method was 3.6%. A comparison between the mass fragmentographic method and a routine method for determination of serum urea based on the urease-Berthelot reaction gave a high correlation (r = 0.99) and a regression coefficient of 0.95.
Clin Chim Acta 1976 Sep 06
PMID:Determination of serum urea by mass fragmentography. 0 11

Meralluride, mercaptomerin, ethacrynic acid, and penicillamine inhibited urease activity of Proteus mirabilis. The activity of the organic mercurials and ethacrynic acid was markedly inhibited by human and dog urine. Antiurease activity could not be detected in the urine of a human and a dog given meralluride by injection. Urine from patients receiving penicillamine also failed to inhibit urease activity. Ascorbic acid inhibited, whereas dehydroascorbic acid enhanced, the activity of the mercurials, but neither agent altered the inhibitory effect of urine. The lethal effect of meralluride against Proteus occurred at the same concentration at which urease activity was inhibited, but penicillamine inhibited the enzymatic activity without affecting viability of the organism. The data suggest that these sulfhydryl-reactive compounds will not be useful against Proteus infections of the urinary tract.
Antimicrob Agents Chemother 1976 Sep
PMID:Effect of organic mercurials and sulfhydryl compounds on the urease activity of Proteus: inhibition by urine and ascorbic acid. 1 Aug 28

The final products of the arginine catabolism that can be utilized as a nitrogen source in Neurospora crassa are ammonium, glutamic acid, and glutamine. The effect of these compounds on arginase induction by arginine was studied. In wild-type strain 74-A, induction by arginine was almost completely repressed by glutamic acid plus ammonium, whereas ammonium or glutamic acid alone had only moderate effects. Arginine products of catabolism also repressed arginase induction. A mutant, ure-1, which lacks urease activity, hyperinduced its arginase with arginine as a nitrogen source. The addition of either ammonium or glutamine produced effects similar to those in the wild-type strain. The effect of ammonium on arginase induction is mediated through its conversion into glutamine. This was demonstrated in mutant am-1, which lacks L-glutamate dehydrogenase activity. In this mutant, the effect of glutamic acid was reduced, and, with ammonium, it was completely lost. The addition of glutamine or glutamic acid plus ammonium to this strain decreased by threefold the induction of arginase by arginine. Proline, a final product of arginine catabolism, competitively inhibited arginase activity. This effect and the repression of arginase by glutamine are examples of negative modulation of the first enzyme in a catabolic pathway by its final products.
J Bacteriol 1977 Sep
PMID:Nitrogen regulation of arginase in Neurospora crassa. 14 62

The activities of three enzymes present in soil, phosphatases, urease, and decarboxylase, were monitered as indicators of the loss of biochemical information occurring when soil was sterilized by dry heat (0.08% relative humidity), gamma radiation, or a combination of both. More enzymatic activity was retained in soil sterilized by a long exposure to dry heat at relatively low temperature (8 weeks at 100.5 degrees C) than by a shorter exposure to a higher temperature (2 weeks at 124.5 degrees C). No enzymatic activity was detectable in soil sterilized by an even higher temperature (4 days at 148.5 degrees C). Soil sterilized with 7.5 Mrads of radiation retained much higher enzymatic activity than with heat sterilization. Combining sublethal doses of heat radiation effectively sterilized the soil and yielded enzymatic activities higher than those of soil sterilized by dry heat alone but lower than those of soil sterilized by radiation.
Orig Life 1978 Sep
PMID:Degradation of biochemical activity in soil sterilized by dry heat and gamma radiation. 21 35

A study was made of 268 cultures isolated from the urine of 263 children suffering from pyelonephritis. Of the total number of different cultures E. coli constituted 79.3 percent; the percentage of the rest varied from 5.2 to 0.4. Examination of 87 urinocultures of E. coli isolated from sick children with the specific immune response showed that the majority of bacterial signs (urease activity, capacity to produce alpha-hemolysin to utilize saccharose and raffinose, to synthesize colicine) failed to correlate with their pyelopathogenicity. The reference to individual serological groups also failed to serve as a sufficient foundation for the separation of these microbes into individual nephropathogenic or pyelopathogenic groups. In experiments with 3H-glucose labeled bacteria there was revealed a marked adhesive capacity in 94 percent of E. coli strains towards the epithelial cells of the RH strain. A positive radioactive label failed to correlate with the presence in E. coli of common pili and with the bacterial agglutinability with the sera K88, K99, and KH-III. The latter pointed to the presence of a factor of unknown nature in the nephropathogenic E. coli strains imparting adhesive properties to bacteria.
Zh Mikrobiol Epidemiol Immunobiol 1977 Sep
PMID:[Characteristics of microbial cultures in bacteriuria and various data on the immunological reaction in children with pyelonephritis]. 33 27

Proteus strains isolated from the gastro-intestinal tract of children not older than 1 year were characterized by resistance to oxytetracycline, chlortetracycline, benzylpenicillin and erythromycin. The strains were more sensitive to neomycin, monomycin and streptomycin. Antibiotic sensitivity of Pr. mirabilis and Pr. vulgaris strains increased on transfer from H- to O-form. Inverse dependence of the urease activity of the strains on their sensitivity to tetracyclines was noted.
Antibiotiki 1978 Sep
PMID:[Antibiotic sensitivity of the H- and O-forms of bacteria in the genus Proteus]. 35 11

Twenty-four lactose-fermenting, urease-producing strains of beta-hemolytic Escherichia coli were isolated from a variety of clinical material. All isolates were indole positive, citrate negative, and produced the characteristic green metallic sheen on eosin-methylene blue agar.
J Clin Microbiol 1978 Sep
PMID:Urease production from clinical isolates of beta-hemolytic Escherichia coli. 35 96

The Micro-ID system for rapid (4 h) identification of Enterobacteriaceae was evaluated by testing 433 enteric bacilli and 9 other gram-negative bacilli. Each isolate was identified with conventional tubed media and was also tested in the Micro-ID and API 20E systems. The overall accuracy of both systems was 97%. Micro-ID tests for the Voges-Proskauer reaction, indole and H2S production, and ornithine and lysine decarboxylase all demonstrated a 97 to 99% correlation with conventional methods. Only 86% of the Micro-ID urease tests agreed with Christenson urea agar. Two inoculum densities were tested in Micro-ID panels, with 157 stock cultures. Over 90% of the tests were unaffected by changes in inoculum density. Tests with four control strains suggested that the Micro-ID system was more reproducible when a light inoculum was used. The Micro-ID system was found to be a very convenient method for rapid, accurate, and precise identification of the Enterobacteriaceae.
J Clin Microbiol 1979 Sep
PMID:Rapid identification of Enterobacteriaceae with the micro-ID system versus API 20E and conventional media. 38 17

The new API 20C yeast identification system together with appropriate microscopic morphology determinations achieved a 97% correlation with a rapid conventional method. Whereas a group composed of Candida, Torulopsis, Saccharomyces, and Rhodotorula was identified with ease (98% overall correlation), a second group, containing Cryptococcus, Trichosporon, and Geotrichum species, appeared to give the system the most difficulty (90% correlation). Within this group particular difficulty was encountered in identifying varieties of Cryptococcus albidus, C. terreus, C. laurentii, Trichosporon beigelli, and Geotrichum spp. as to species. The API 20C system should be incubated the full 72 h prescribed by the manufacturer. However, when used in conjunction with appropriate morphological tests, presumptive identifications of some Candida and Torulopsis species may be made at 24 to 48 h. To facilitate identifications of the more difficult group of yeasts, ancillary tests for determining nitrate reductase, urease, and phenol oxidase activities should be considered as additions to the strip. Incorporating the phenol oxidase test would be especially important for identification of Cryptococcus neoformans, a yeast which should be identified as quickly and as accurately as possible. The API 20C system with computer assistance has proved to be an easy-to-inoculate, versatile, and fairly rapid method of yeast identification, giving results comparable to those obtained by conventional methodologies.
J Clin Microbiol 1979 Sep
PMID:Evaluation of the new API 20C strip for yeast identification against a conventional method. 38 21


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