Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recognition of -24/-12-type promoters by RNA polymerase requires a special sigma factor, sigma 54 (RpoN NtrA GlnF). In the nitrogen-fixing soybean symbiont Bradyrhizobium japonicum, two functional, highly conserved rpoN genes (rpoN1 and rpoN2) were identified and sequenced. The two predicted B. japonicum RpoN protein sequences were 87% identical, and both showed different levels of homology to the RpoN proteins of other bacteria. Downstream of rpoN2 (but not of rpoN1), two additional open reading frames were identified that corresponded to open reading frames located at similar positions in Klebsiella pneumoniae and Pseudomonas putida. Both B. japonicum rpoN genes complemented the succinate- and nitrate-negative phenotypes of a Rhizobium meliloti rpoN mutant. B. japonicum strains carrying single or double rpoN mutations were still able to utilize C4-dicarboxylates as a carbon source and histidine, proline, or arginine as a nitrogen source, whereas the ability to assimilate nitrate required expression of at least one of the two rpN genes. In symbiosis both rpoN genes could replace each other functionally. The rpoN1/2 double mutant induced about twice as many nodules on soybeans as did the wild type, and these nodules lacked nitrogen fixation activity completely. Transcription of a nifH'-'lacZ fusion was not activated in the rpoN1/2 mutant background, whereas expression of a fixR'-'lacZ fusion in this mutant was affected only marginally. By using rpoN'-'lacZ fusions, rpoN1 expression was shown to be activated at least sevenfold in microaerobiosis as compared with that in aerobiosis, and this type of regulation involved fixLJ. Expression of rpoN2 was observed under all conditions tested and was increased fivefold in an rpoN2 mutant. The data suggested that the rpoN1 gene was regulated in response to oxygen, whereas the rpoN2 gene was negatively autoregulated.
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PMID:Bradyrhizobium japonicum has two differentially regulated, functional homologs of the sigma 54 gene (rpoN). 199 12

An increased risk of bladder cancer is a recognized complication in spine-injured patients undergoing long-term urethral catheterization to preserve renal function. Aerobic cultures from 28 of 30 paraplegic patients showed complex bacterial flora containing nitrate-reducing organisms (Escherichia coli, Proteus and Klebsiella spp.). Urine samples from 29 paraplegic patients were also found to contain volatile nitrosamines. Mean N-nitrosamine excretion levels were 0.65 +/- 0.69 micrograms/day N-nitrosodimethylamine, 0.25 +/- 0.44 micrograms/day N-nitrosopiperidine and 0.39 +/- 0.50 micrograms/day N-nitrosopyrrolidine. A mean urinary nitrite excretion of 10.4 +/- 13.2 mg/day was found in 24 out of 30 paraplegic patients. In the sterile urine of control volunteers (medical staff attending the paraplegic patients and in-patients from other wards of the hospital), no urinary excretion of volatile N-nitrosamines and nitrite was found. The results clearly demonstrate a bacterially mediated in vivo formation of N-nitroso compounds in the urinary tracts of paraplegic patients which may be an important etiological risk factor for bladder cancer in this patient group.
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PMID:Increased urinary nitrosamine excretion in paraplegic patients. 202 61

We cloned the narL gene, required for nitrate induction of respiratory nitrate reductase synthesis, from Klebsiella pneumoniae. The E. coli narL gene product shares sequence similarity with the response regulator proteins of two-component regulatory systems. We found that narL(+)-containing plasmids restored nitrate regulation of anaerobic respiratory gene expression in appropriate Escherichia coli hosts. The K. pneumoniae narL region encoded a protein whose migration in Laemmli gels was indistinguishable from that of the narL product of E. coli. We constructed a narL::Km mutant of K. pneumoniae. This mutation abolished nitrate induction of respiratory nitrate reductase synthesis but had no effect on nitrate induction of assimilatory nitrate and nitrite reductase synthesis. We conclude that K. pneumoniae has distinct nitrate-responsive regulators for controlling respiratory and assimilatory gene expression.
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PMID:Genetic evidence that NarL function is not required for nitrate regulation of nitrate assimilation in Klebsiella pneumoniae M5al. 219 61

Klebsiella aerogenes W70 could grow aerobically with nitrate or nitrite as the sole nitrogen source. The assimilatory nitrate reductase and nitrite reductase responsible for this ability required the presence of either nitrate or nitrite as an inducer, and both enzymes were repressed by ammonia. The repression by ammonia, which required the NTR (nitrogen regulatory) system (A. Macaluso, E. A. Best, and R. A. Bender, J. Bacteriol. 172:7249-7255, 1990), did not act solely at the level of inducer exclusion, since strains in which the expression of assimilatory nitrate reductase and nitrite reductase was was independent of the inducer were also susceptible to repression by ammonia. Insertion mutations in two distinct genes, neither of which affected the NTR system, resulted in the loss of both assimilatory nitrate reductase and nitrite reductase. One of these mutants reverted to the wild type, but the other yielded pseudorevertants at high frequency that were independent of inducer but still responded to ammonia repression.
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PMID:Regulation of assimilatory nitrate reductase formation in Klebsiella aerogenes W70. 225 83

One hundred and seventy-two burn wound swabs obtained from 90 patients admitted to the Aljila Hospital Burn Unit, Benghazi over a 3-month period were processed to determine the microbial flora colonizing burns and their resistance patterns to selected locally available topical and systemic agents. Approximately 84.9 per cent of the swab specimens yielded growth of 11 bacterial species and Candida spp.; of these, Ps. aeruginosa, Staph. aureus and Klebsiella spp. predominated in order of prevalence, followed by Enterobacteria. Polymyxin (100 per cent sensitive), amicacin (90.9 per cent sensitive) and carbenicillin (66.7 per cent sensitive) were the most effective of 10 selected antibiotics tested against the 60 pseudomonas isolates. In studies in vitro using six topical agents, Ps. aeruginosa strains were most sensitive, in decreasing order, to mafenide acetate, silver sulphadiazine, acetic acid, silver nitrate and Eusol. Seventy-eight per cent of Staph. aureus isolates were resistant to methicillin and erythromycin and 93 per cent to tetracycline.
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PMID:Analysis of infection in a burn ward. 251 53

No holoenzyme pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase and only very low apoenzyme levels could be detected in cells of Klebsiella pneumoniae, growing anaerobically, or carrying out a fumarate or nitrate respiration. Low glucose dehydrogenase activity in some aerobic glucose-excess cultures of K. pneumoniae (ammonia or sulphate limitation) was increased significantly by addition of PQQ, whereas in cells already possessing a high glucose dehydrogenase activity (phosphate or potassium limitation) extra PQQ had almost no effect. These observations indicate that the glucose dehydrogenase activity in K. pneumoniae is modulated by both PQQ synthesis and synthesis of the glucose dehydrogenase apo-enzyme.
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PMID:The separate roles of PQQ and apo-enzyme syntheses in the regulation of glucose dehydrogenase activity in Klebsiella pneumoniae NCTC 418. 253 92

We isolated Mu dI1734 insertion mutants of Klebsiella pneumoniae that were unable to assimilate nitrate or nitrite as the sole nitrogen source during aerobic growth (Nas- phenotype). The mutants were not altered in respiratory (anaerobic) nitrate and nitrite reduction or in general nitrogen control. The mutations were linked and thus defined a single locus (nas) containing genes required for nitrate assimilation. beta-Galactosidase synthesis in nas+/phi(nas-lacZ) merodiploid strains was induced by nitrate or nitrite and was inhibited by exogenous ammonia or by anaerobiosis. beta-Galactosidase synthesis in phi(nas-lacZ) haploid (Nas-) strains was nearly constitutive during nitrogen-limited aerobic growth and uninducible during anaerobic growth. A general nitrogen control regulatory mutation (ntrB4) allowed nitrate induction of phi(nas-lacZ) expression during anaerobic growth. This and other results suggest that the apparent anaerobic inhibition of phi(nas-lacZ) expression was due to general nitrogen control, exerted in response to ammonia generated by anaerobic (respiratory) nitrate reduction.
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PMID:Genetic regulation of nitrate assimilation in Klebsiella pneumoniae M5al. 254 Jan 53

Tumor development at the site of ureterointestinal anastomosis is a recognized complication in patients with continent urinary diversions. Aerobic cultures of rectal urine samples from 30 patients with urinary diversions (26 ureterosigmoidostomies, two colon conduits, one ileal conduit and a Gersuny bladder) showed a complex bacterial flora containing nitrate-reducing organisms (Escherichia coli, Proteus and Klebsiella spp.). In comparison to normal bladder urine samples from control volunteers (n = 20), rectal urine samples from ureterosigmoidostomy patients (n = 26) showed a significant decrease (P less than 0.0001) in urinary nitrate (0.93 +/- 0.39 versus 0.27 +/- 0.23 mmol/l), a significant increase (P less than 0.0001) in urinary nitrite (not detected versus 29.24 +/- 39.93 mumol/l) as well as a significant increase (P = 0.013) in urinary N-nitroso compound excretion (57.33 +/- 33.87 versus 93.96 +/- 65.76 nmol/l). Significant increases were also found for the urinary excretion of individual volatile and non-volatile N-nitroso compounds, clearly demonstrating a bacterially mediated in vivo formation of N-nitroso compounds in the 'colon' bladders of patients with urointestinal diversions that may be an important etiological risk factor for colon carcinogenesis in this patient group.
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PMID:Increased urinary nitrosamine excretion in patients with urinary diversions. 259 Oct 28

Hybrid 5' regulatory regions were constructed in which the upstream activator sequence (UAS) and promoter of various nif genes were exchanged with the upstream regulatory sequence (URS) of the fdhF gene from Escherichia coli. They were analysed for their regulatory response under different growth conditions with the aid of fdhF'-'lacZ or nif'-'lacZ fusions. Placement of the UAS from the Bradyrhizobium japonicum nifH gene in front of the spacer (DNA region between URS and promoter) plus promoter from fdhF renders fdhF expression activatable by the Klebsiella pneumoniae NIFA protein, both under aerobic and anaerobic conditions. This excludes the possibility that the spacer of the fdhF5' flanking region contains a site recognized by a putative oxygen- or nitrate-responsive repressor. There was also considerable activation by NIFA of fdhF expression in a construct lacking the nifH UAS but containing the fdhF spacer plus promoter. Further experimental evidence suggests that this reflects a direct interaction between NIFA and RNA polymerase at the ntrA-dependent promoter. A second set of hybrid constructs in which the URS from fdhF (E. coli) was placed in front of the nifD spacer plus promoter from B. japonicum or in front of the K. pneumoniae nifH, nifU, nifB spacers and promoters, delivered inactive constructs in the case of the nifD, nifU and nifB genes. However, a nifH'-'lacZ fusion preceded by its own spacer and promoter plus the foreign fdhF URS displayed all the regulatory characteristics of fdhF expression, i.e. anaerobic induction with formate and repression by oxygen and nitrate. Although it is not known why only one out of the four nif promoters could be activated by the fdhF URS, this result nevertheless demonstrates that the various regulatory stimuli affecting expression of fdhF in E. coli have their target at the upstream regulatory sequence.
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PMID:Construction of chimaeric promoter regions by exchange of the upstream regulatory sequences from fdhF and nif genes. 266 22

Multidrug-resistant (MDR) clinical isolates of Klebsiella pneumoniae were checked for their sensitivity toward silver nitrate by the tube-dilution method. Nearly 75% of MDR strains could be successfully inhibited by 5 mg/L of silver nitrate. A significant correlation was observed between incidence of silver and trimoxazole resistance and silver and kanamycin resistance in these isolates. The genetic linkage of these two properties could not be proved since simultaneous curing and co-transfer studies gave negative results.
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PMID:Susceptibility of multidrug-resistant isolates of Klebsiella pneumoniae to silver nitrate. 266 88


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