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:1.7.1.2 (nitrate reductase)
3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A useful method for isolating and recognizing Haemophilus ducreyi from chancres and buboes of male patients is presented. A total of 41 clinical isolates of H. ducreyi were recovered from 33 patients over an 8-year period, and the experience with the 15 most recent isolates is presented in detail. Chocolate agar supplemented with 1% Iso VitaleX and 5% sheep blood agar were prepared, using Trypticase soy and Mueller-Hinton Agar bases, and incubation conditions included ambient, capneic, and anaerobic environments. Mueller-Hinton agar was clearly superior over Trypticase soy agar for isolation of H. ducreyi, although there was little difference between 5% sheep blood and supplemented chocolate agar. Growth in ambient air and under anaerobiasis was poor or lacking, whereas growth in 5 to 7% CO2 was good to luxuriant. Heat-inactivated and fresh (unheated)human blood clot tubes also were used for selective isolation. Although the rates of isolation from the two types of clot tube were not significantly different, unheated clot tubes were superior to heated clot tubes because of reduced level of contaminants. Gram stain characteristics taken from blood clot tubes and solid media, cellular and colonial morphology of the bacilli, and lack of oxidase, catalase, and biochemical activity except nitrate reductase were determinant factors. The results of this study demonstrated that successful isolation of H. ducreyi can be achieved with a minimal amount of resources and expertise.
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PMID:Isolation and cultivation of Haemophilus ducreyi. 680 70

Strains of a new type of slowly growing mycobacterium were repeatedly isolated from sputum from a patient with pulmonary disease. This photochromogenic organism grew at 22, 31, 37, and 41 degrees C, possessed catalase, acid phosphatase, esterase, beta-galactosidase, and arylsulfatase activities, and hydrolyzed Tween. It did not produce nicotinic acid or have nitrate reductase, acetamidase, benzamidase, isonicotinamidase, nicotinamidase, pyrazinamidase, succinidamidase, and acid phosphatase activities. Urease activity was variable. The organism is susceptible to ethambutol and resistant to isoniazid and streptomycin. A mycolic acid analysis revealed the presence of alpha-mycolates, alpha'-mycolates, and keto-mycolates. The results of comparative 16S rRNA sequencing placed this organism at an intermediate position between the rapidly and slowly growing mycobacteria. On the basis of the pattern of enzymatic activities and metabolic properties, the results of fatty acid analyses, and the unique 16S rRNA sequence, we propose that this organism represents a new species, for which we propose the name Mycobacterium intermedium. The type strain is strain 1669/91; a culture of this strain has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen as strain DSM 44049.
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PMID:Mycobacterium intermedium sp. nov. 849 35

A number of mycobacterial strains with similar growth characteristics, metabolic properties, and lipid compositions, which were previously placed in the Helsinki group (E. Brander, E. Jantzen, R. Huttunen, A. Juntunen, and M.-L. Katila, J. Clin. Microbiol. 30:1972-1975, 1992), were characterized by performing 16S rRNA gene sequencing. Of the 14 strains studied, 9 had a unique, previously undescribed sequence in the variable region of 16S rRNA. These nine strains, all of which were isolated from respiratory tract specimens, were nonpigmented and grew at 25 degrees C to 45 degrees C, reaching full colony size after 2 to 3 weeks. They produced arylsulfatase, nicotinamidase, and pyrazinamidase and were negative for Tween 80 hydrolysis, catalase, urease, and nitrate reductase activities, and niacin. Their glycolipid patterns were identical. A mycolic acid analysis performed by using thin-layer chromatography showed that these organisms contained alpha-mycolates, ketomycolates, and carboxy mycolates. Gas-liquid chromatography revealed that 2-eicosanol was the major alcohol and hexacosanoic acid was the major mycolic acid cleavage product. On the basis of their growth, biochemical, and lipid characteristics and their unique 16S rRNA sequence, we propose that these organisms should be assigned to a new species, Mycobacterium branderi. Comparative 16S rRNA sequencing revealed that this new species is closely related to Mycobacterium celatum, Mycobacterium cookii, and Mycobacterium xenopi. Strains 52157T (T = type strain) and 43548 have been deposited in the American Type Culture Collection as strains ATCC 51789 and ATCC 51788, respectively.
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PMID:Mycobacterium branderi sp. nov., a new potential human pathogen. 859 Jun 82

Assimilatory NADH:nitrate reductase catalyzes the transfer of reducing equivalents from NADH to molecular oxygen. Initial rate studies performed under conditions of optimal pH (8.0) and constant ionic strength (mu = 0.2) revealed that the maximal rate of activity with molecular oxygen was 0.5% (0.44 mumol NADH consumed/min/nmol heme) with a Km for O2 of 586 microM. NADH:molecular oxygen reductase activity exhibited a pH optimum of 9.2, was inhibited by cyanide, and was unaffected by changes in ionic strength or the presence of phosphate ions. Spectroscopic studies indicated NADH:molecular oxygen reductase activity resulted in the production of the superoxide radical, detected as the formation of adrenochrome from epinephrine and by the formation of adrenochrome from epinephrine and by the reduction of nitroblue tetrazolium, both of which could be inhibited by the addition of superoxide dismutase and were unaffected by the addition of catalase. Direct observation of superoxide production using spin-trapping in combination with EPR spectroscopy resulted in the detection of the spin adduct 5.5-dimethyl-5-hydroxy-1-pyrrolidinyloxy (DMPO-OH). The formation of this spin adduct was abolished either in the absence of nitrate reductase, NADH, or DMPO or the the addition of superoxide dismutase or nitrate and was greatly reduced by the presence of cyanide. Inclusion of catalase or ethanol had no effect on the formation of the spin adduct. These results indicate that nitrate reductase can utilize molecular oxygen as an electron acceptor and that the product, O2.(-), is primarily generated via the Mopterin center.
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PMID:Superoxide production during reduction of molecular oxygen by assimilatory nitrate reductase. 861 Oct 27

A distinct group of slowly growing mycobacteria was identified on the basis of growth characteristics, biochemical and lipid profiles, and nucleic acid analyses. The isolates showed growth at 22 to 37 degrees C, yellow pigmentation, and negative tests for Tween 80 hydrolysis, nicotinic acid, nitrate reductase, and urease; tests for arylsulfatase, pyrazinamidase, and heat-stable catalase were variable. Analysis of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography and high-performance liquid chromatography indicated a distinctive pattern which was unlike those of other species. Determination of the 16S rRNA gene sequence showed a unique sequence closely related to Mycobacterium simiae and M. genavense. On the basis of DNA homology studies, we suggest that these organisms are representatives of a novel species, for which the name M. lentiflavum sp. nov. is proposed.
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PMID:Isolation and characterization of a unique group of slowly growing mycobacteria: description of Mycobacterium lentiflavum sp. nov. 872 84

We have isolated two phenotypically distinct nonfastidious Francisella strains (Fx1 and Fx2) from the blood of compromised patients with pneumonia and compared them with eight other Francisella strains, including Francisella tularensis biovar tularensis, F. tularensis biovar novicida, and F. philomiragia. Our isolates grew well on sheep blood agar, chocolate agar, modified Thayer-Martin agar, and Trypticase soy agar. Fx1 and Fx2 were determined to be within the Francisella genus by cellular fatty acid analysis and by the utilization of glucose, production of H2S and catalase, and lack of motility, oxidase, nitrate reductase, and gelatinase. They were additionally shown to belong to the species F. tularensis by sequencing of two variable regions comprising approximately 500 nucleotides of the 16S rRNA gene. Also, RNA probe hybridization confirmed their belonging to the species F. tularensis. However, the new strains, which are not identical, are distinguished from other F. tularensis strains by growth characteristics, repetitive extragenic palindromic PCR fragment pattern, and some biochemical tests. Key biochemical differences included the findings that Fx1 was positive for beta-galactosidase and arabinose hydrolysis and that both strains were citrulline ureidase positive and glycerol negative. Commercial F. tularensis antiserum agglutinated stock F. tularensis strains but not Fx1, Fx2, F. tularensis biovar novicida, or F. philomiragia; serum from either patient failed to agglutinate or only weakly agglutinated commercial antigen but showed agglutination when tested against each patient's respective isolate. Fx1 and Fx2 produced beta-lactamase. Because of their good growth, negative serology, and biochemical profile, the organisms could be misidentified in the clinical laboratory if standard strategies or commercial identification systems are used.
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PMID:Characterization of two unusual clinically significant Francisella strains. 881 97

From two different specimens of a chronic prosthetic hip infection taken at an interval of 2 months a slow-growing gram-negative bacterium was isolated in pure culture. The strain grew with the typical features of a small-colony variant (SCV). 16S rRNA sequencing identified the bacterium as Escherichia coli. Biochemical characterization demonstrated multiple phenotypic alterations of a mutant carrying a defect in the heme biosynthetic pathway (Hem-): (i) catalase and nitrate reductase reactions were both negative, (ii) a negative benzidine reaction demonstrated the lack of heme-containing cytochromes, and (iii) growth stimulation under anaerobic conditions as well as gentamicin resistance indicated defective aerobic respiration. PCR and Southern hybridization demonstrated that the mutation of the SCV of E. coli was localized in the hemB gene and was most likely due to a deletion of the hemB gene. On blood agar plates revertants were recognized growing as normal-sized colonies between the dominant small colonies of the strain. Feeding experiments indicated that the revertants but not the small colonies were permeable for hemin. A strong antibody response against the infecting SCV of E. coli was found. To our knowledge, this is the first report of a Hem- E. coli strain as the etiological agent of a chronic bacterial infection.
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PMID:Chronic prosthetic hip infection caused by a small-colony variant of Escherichia coli. 970 87

In accordance with Recommendation 30b of the International Code of Nomenclature of Bacteria, minimal standards are proposed for the genus Staphylococcus and the description of newly recognized species in this genus. Assignment of a strain to the genus Staphylococcus requires that it is a Gram-positive coccus that forms clusters, produces catalase, has an appropriate cell wall structure (including peptidoglycan type and teichoic acid presence) and G + C content of DNA in a range of 30-40 mol%. The recommended minimal standards for describing a new Staphylococcus species are based on the results of phenotypic and genomic studies of at least five independently isolated strains. They include colony morphology and the results of the following conventional tests: pigment production, growth requirements, fermentative and oxidative activity on carbohydrates, novobiocin susceptibility, enzymic activities (nitrate reductase, alkaline phosphatase, arginine dihydrolase, ornithine decarboxylase, urease, cytochrome oxidase, staphylocoagulase in rabbit plasma, heat-stable nuclease, amidases, oxidases, clumping factor, and haemolytic activity on sheep or bovine blood agar). DNA-DNA hybridization experiments may distinguish species when the difference between the binding in the homologous reaction and the binding in the heterologous reaction expressed as a percentage is less than 70%. In addition, rRNA signature sequence criteria, ribotyping characterization of the nomenclature type strain and other strains of the species, and reference strains of other species is recommended to describe the strains of the new species with sets of genetic attributes and reveal possible grouping errors. This proposal has been endorsed by the members of the Subcommittee on the taxonomy of staphylococci and streptococci of the international Committee on Systematic Bacteriology.
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PMID:Recommended minimal standards for description of new staphylococcal species. Subcommittee on the taxonomy of staphylococci and streptococci of the International Committee on Systematic Bacteriology. 1031 69

A new, slow-growing, scotochromogenic mycobacterium was isolated from a lymph node of an immunocompromised child and subsequently from tap water and from a respiratory specimen of a patient with chronic fibrosis. Alcohol-acid-fastness, lipid patterns and the G + C content clearly support the placement of this organism in the genus Mycobacterium. The isolates grew very slowly at temperatures ranging from 25 to 32 degrees C and showed activities of nitrate reductase, catalase, urease, arylsulfatase and Tween 80 hydrolysis. The organism was susceptible to all antimycobacterial drugs tested. The 16S rDNA sequence was unique and phylogenetic analysis placed the organism close to fast-growing species such as Mycobacterium farcinogenes, Mycobacterium komossense and Mycobacterium aichiense. These data support the conclusion that the isolates represent a new mycobacterial species, for which the name Mycobacterium tusciae sp. nov. is proposed. The type strain is strain FI-25796T; a culture of this strain has been deposited in the DSMZ as strain DSM 44338T.
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PMID:Mycobacterium tusciae sp. nov. 1055 67

The objective of this work was to study the production of catalase and nitrate reductase by staphylococci in order to understand their role in lipid oxidation during sausage manufacturing. Catalase and nitrate reductase were measured in resting cells and supernatants of staphylococci grown in different conditions. All staphylococci (except S. warneri) synthetized nitrate reductase. In static condition, the synthesis was maximal during exponential growth phase, whereas in shaking condition, the synthesis was maximal at the beginning of stationary phase. The production of nitrate reductase was increased in presence of nitrate, this effect was particularly important for the two S. carnosus strains which exhibited the highest activity. For all staphylococci, the production of catalase was maximal at the end of the exponential growth phase. The lowest amount of catalase was produced by S. warneri and the highest by S. carnosus. Only S. xylosus 873 and S. saprophyticus 852 released high amounts of catalase in the supernatant growth. Staphylococci produced higher amounts of catalase in shaking conditions. Addition of nitrate in the growth media favoured the synthesis of catalase, with a pronounced effect for S. carnosus. Nitrate also favoured the release of catalase.
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PMID:Effect of nitrate and incubation conditions on the production of catalase and nitrate reductase by staphylococci. 1057 91


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