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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heat output-time records or 'thermograms' produced during the aerobic growth of Klebsiella aerogenes in simple salts/glucose media with growth limiting glucose concentrations of 2.0, 1.0 and 0.5 g dm-3 were obtained using a flow-microcalorimeter fitted with an aerobic cell. These traces are interpreted in terms of the recorded oxygen tension, pH, glucose concentration and bacterial population of the culture. Heat output is greatest during the phase of exponential growth, indicating that here the organisms are most energetically inefficient. During the stationary phase aerobic processes, which give rise to a low oxygen tension, produce a smaller heat output until secondary metabolic processes are complete.
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PMID:A microcalorimetric study of the growth of Klebsiella aerogenes in simple salts/glucose media. 1 49

Net lung bacterial clearance in normal mice is determined by the balance of in vivo bacterial multiplication on the one hand, and the defense mechanisms of mucociliary clearance and phagocytosis and killing by the oxygen-dependent alveolar macrophage on the other. The bactericidal function of the macrophage is the major component of the defense mechanism. The effect of acute hypoxia on the defense mechanism was studied in mice exposed to aerosols of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Streptococcus pneumoniae. Physical clearance was not impaired by acute hypoxia, and bacterial replication was not stimulated by the low oxygen atmosphere. Clearance of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli was impaired during acute hypoxia due to decreased phagocytosis or killing by the alveolar macrophage. The important human pathogen Streptococcus pneumoniae was cleared normally in the presence of acute hypoxia. This observation suggests that an oxygen-independent clearance mechanism is important in lung defense against the pneumococcus. This may be a separate mechanism within the alveolar macrophage or a system as yet unidentified.
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PMID:Determinants of lung bacterial clearance in mice after acute hypoxia. 2 3

Rates of nitrogenase synthesis by Klebsiella pneumoniae were measured by pulse-labelling organisms with a mixture of 14C-labelled amino acids followed by sodium dodecyl sulphate gel electrophoresis and autoradiography. Populations from an NH4+-repressed, SO42--limited chemostat (0.46 mg dry wt ml-1), when released from NH4+ repression, simultaneously synthesized detectable quantities of the three nitrogenase polypeptides 45 min before acetylene-reducing activity was observed. Exposure of populations synthesizing nitrogenase to air or NH4+ (200 microgram N ml-1) repressed synthesis of both component proteins simultaneously, the rate initially decreasing by half in 11 to 12 min; in the presence of NH4+ a second slower phase with an approximate half-life of 30 min was observed. With 5% O2 in N2 the half-lives for the decreases in the rates of synthesis were 30 min for the Fe protein and 33 min for the Mo-Fe protein. Oxygen also repressed nitrogenase in a glutamine synthetase constitutive derivative of K. pneumoniae (strain SK24) which escapes NH4+ repression. Regulation of nitrogenase by O2 may therefore be independent of glutamine synthetase.
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PMID:Nitrogenase synthesis in Klebsiella pneumoniae: comparison of ammonium and oxygen regulation. 2 75

The ingestion rate and oxygen-dependent metabolic activities of normal human polymorphonuclear leucocytes were measured with heat-killed Klebsiella as the particle. Since the experimental conditions were similar for each measurement, it was possible to make direct correlations between each oxygen-dependent reaction and (1) ingestion rate and (2) the other oxygen-dependent reactions. In the controls, oxygen-uptake was more reliably correlated (r = 0.960) with ingestion rates than with (in order of reliability) hydrogen peroxide produced (r = 0.860) and iodination (r = 0.858 and 0.813 for 100 and 20 micromol/l iodide respectively). Hydrogen peroxide production (r = 0.988), nitroblue tetrazolium reduction (r = 0.969) and cytochrome c reduction (r = 0.862) were more reliably correlated to oxygen-uptake than to ingestion rate, and iodination was better related to hydrogen peroxide production (r = 0.90 and 0.819 for 100 and 20 micromol/l iodide respectively) than to ingestion rate. From these findings it was possible to locate primary defects in abnormal polymorphonuclear leucocytes from individual patients with pyogenic infections, idiopathic refractory anaemia or idiopathic oesteomyelofibrosis with splenomegaly, even when several deficiencies existed.
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PMID:Metabolic activity of human polymorphonuclear leucocytes: relation to ingestion rate. 11 22

A molybdenum cofactor (Mo-co) from xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) can be isolated from the enzyme by a technique that has been used to isolate an iron-molybdenum cofactor (FeMo-co) from component I of nitrogenase. N-Methylformamide is used for the extraction of these molybdenum cofactors. Mo-co from xanthine oxidase activates nitrate reductase (NADPH:nitrate oxidoreductase, EC 1.6.6.2) in an extract from Neurospora crassa mutant strain Nit-1; however, FeMo-co is unable to activate nitrate reductase in strain Nit-1. Mo-co from xanthine oxidase is unable to activate nitrogenase in an extract of Azotobacter vinelandii mutant strain UW45. Inactive component I in this extract can be activated by FeMo-co. These results indicate that nitrate reductase and xanthine oxidase share a common molybdenum cofactor, but this cofactor is different from the molybdenum cofactor in nitrogenase.A. vinelandii synthesizes both Mo-co and FeMo-co. Mo-co is produced when the cells fix N(2) and also when they are repressed for nitrogenase synthesis by growth in a medium containing excess ammonium. However, FeMo-co is not produced when cells are grown in an ammonium-containing medium. Partially purified preparations of component I from A. vinelandii and Klebsiella pneumoniae contain both FeMo-co and Mo-co. The presence of both FeMo-co and Mo-co activities in partially purified preparations of component I explains previous reports of activation of inactive nitrate reductase in strain Nit-1 by acid-treated component I of nitrogenase. The Mo-co can be separated from FeMo-co in these preparations by chromatography on Sephadex G-100 in N-methylformamide. Both FeMo-co and Mo-co are sensitive to oxygen.
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PMID:Molybdenum cofactors from molybdoenzymes and in vitro reconstitution of nitrogenase and nitrate reductase. 14 98

Anaerobic growth of Klebsiella aerogenes NCDO 711 (NCTC 418) on citrate was dependent on the presence of Na+ in the medium, and fermentation of citrate was mediated via the fermentation pathway enzymes, citrate lyase and a Na+-dependent oxalacetate decarboxylase. This confirms the previous findings on strain NCTC 418. Growth under aerobic conditions was independent of Na+. The mean generation time for cells grown aerobically on either Na+ or K+ citrate medium was about 60 min, with a molar growth yield of about 40 g (dry weight) of cells per mol of citrate utilized. Citrate was apparently metabolized aerobically in both the Na+ and K+ citrate cells via the citric acid cycle, since cell extracts contained alpha-ketoglutarate dehydrogenase but not the citrate fermentation enzymes. The presence of theother enzymes of the citric acid cycle in K. aerogenes was shown in earlier studies. Under aerated conditions (no detectable oxygen tension in the culture), growth was faster on the Na+ citrate medium (mean generation time, 85 min) than on the K+ citrate medium (mean generation time, 120 min). Both cultures grew slower than under aerobic conditions, presumably because of oxygen limitation. Despite the faster growth rate, the molar growth yield of the aerated Na+ citrate culture was one-half that observed for the aerated K+ citrate culture. Citrate was metabolized via the citric acid cycle in cells grown in the K+ citrate medium under aerated conditions since alpha-ketoglutarate dehydrogenase, but not the fermentation enzymes, was detected in extracts prepared from these cells. Metabolism of citrate in the Na+ citrate medium under aerated conditions occurred via both the fermentation pathway (approximately 75 percent) and the citric acid cycle (about 25 percent), as evidenced by (i) the presence of the fermentation enzymes and alpha-ketoglutarate dehydrogenase in extracts of cells grown under these conditions, (ii) a molar growth yield which was intermediate between that obtained for anaerobic and aerated K+ citrate cultures, and (iii) the excretion of acetate, which also occurred in anaerobic cultures but not in aerated K+ citrate or aerobic cultures.
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PMID:Effect of aeration and sodium on the metabolism of citrate by Klebsiella aerogenes. 23 80

Normal mice exposed to 10% oxygen concentration developed a slight but statistically significant decrease in blood pH and a slight statistically insignificant decrease in red cell 2,3-DPG. Mice that were infected intraperitoneally with Staphylococcus aureus or Klebsiella pneumoniae and exposed to 20% oxygen developed acidosis, hemoconcentration, and decreased red cell 2,3-DPG levels. When mice with acute bacterial peritonitis were exposed to 10% oxygen concentration they likewise developed significant acidosis and hemoconcentration, but their reduction in red cell 2,3-DPG was not as great as that in the similarly infected mice exposed to 20% oxygen concentration.
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PMID:The effects of Staphylococcus aureus and Klebsiella pneumoniae peritonitis in mice exposed to normal and hypoxic conditions on red cell oxygen transport function. 23 91

Diplococcus pneumoniae remains the most frequent cause of community-acquired bacterial pneumonia. Other frequently isolated bacterial pathogens are Hemophilus influenzae, Klebsiella organisms, and Staphylococcus aureus. The etiologic agents most commonly implicated in hopsital-acquired pneumonias are gram-negative bacilli including E. coli, proteus organisms, and species of Klebsiella-Enterobacter, pseudomonas, and Serratia. Among older children and young-adults, Myocoplasma pneumoniae is a common cause of penumonia. Influenza is the most important cause of viral pneumonia in adults, but there is increasing concern about pulmonary infection due to adenoviruses. In those with a history of travel to endemic areas, the diagnosis of fungal pneumonia due to Histoplasma capsulatrum, Blastomyces dermatitides, or Coccidioides immitis, should be considered. Penumonias due to opportunistic fungi (including species of Candida, Aspergillus, and Phycomycetes) and higher bacteria such as Nocardia asteroides are also on the increase, and these arise mostly in compromised hosts. Treatment of pneumonia almost always must be started before culture results are known and in the overwhelming majority of cases, appropriate regimens can be selected after taking an adquate history, doing a careful physical examination, evaluating expectorated sputum for cells and organisms, and examining the chest x-ray. Although anti-infective agents are the mainstay of treatment for most infectious pneumonias, supportive therapy, including adequate tracheobronchial toilet, drainage of abscesses, oxygen inhalation, maintenance of adequate nutrition, and monitoring for super-infection and anti-infective side effects may be life-saving in certain situations.
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PMID:Infectious pneumonias: a review. 32 Feb 85

The effect of the rate of oxygen supply on biomass growth, consumption of carbon source formation of metabolic by-products, biomass yeilds referred to C-source and oxygen, respiration rate and the respiratory quotient was studied in a multistage tower fermentor with an interstage backflow, i.e. with a continuous reinoculation of the preceding stages. Experiments were done with Klebsiella aerogenes CCM 2318 in a synthetic glucose medium with constant glucose concentration in the feed, at pH 7.0. temperature 30 degrees C, and dilution rates 0.6 and 0.178 h-1 (referred to one stage). Different behavior of the culture was found at different dilution rates both with oxygen and under oxygen limitation. As compared with the chemostat system, the regime with an interstage backflow exhibited differences in respiration rate and CO2 formation; this attests to a considerably different physiological state of the cells.
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PMID:Effect of oxygen supply on growth of Klebsiella aerogenes in a multistage tower fermentor. 34 85

Biomass growth, consumption of carbon and energy source, specific rates of formation of metabolic byproducts, biomass yield referred to the C-source and to oxygen, respiration rate and the value of RQ were studied in Klebsiella aerogenes CCM 2318 (on a synthetic glucose medium) at different specific growth rates. Maintenance coefficients and the total energy balance of the cultivation process were evaluated for a multistage tower fermentor with a defined interstage mixing. The results pointed to changes in both glucose metabolism and the physiological state of the population, brought about by changes in specific growth rate. As compared with a chemostat, the culture was found to exhibit a different physiological character is stages 1 and 4 despite a considerable interstage mixing.
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PMID:Physiological characteristic and energy balance of Klebsiella aerogenes in a multistage tower fermentor. 39 94


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