Obligately anaerobic strains of Corynebacterium vaginale (Haemophilus vaginalis).
(41/951)
Six obligately anaerobic strains of Corynebacterium vaginale (Haemophilus vaginalis) have been isolated and their characteristics studied. The reactions of the anaerobic strains, as well as of facultative strains tested under anaerobic conditions, are similar to the reactions previously reported for this species. (+info)
Quantitative determination of metabolic fluxes during coutilization of two carbon sources: comparative analyses with Corynebacterium glutamicum during growth on acetate and/or glucose.
(42/951)
Growth of Corynebacterium glutamicum on mixtures of the carbon sources glucose and acetate is shown to be distinct from growth on either substrate alone. The organism showed nondiauxic growth on media containing acetate-glucose mixtures and simultaneously metabolized these substrates. Compared to those for growth on acetate or glucose alone, the consumption rates of the individual substrates were reduced during acetate-glucose cometabolism, resulting in similar total carbon consumption rates for the three conditions. By (13)C-labeling experiments with subsequent nuclear magnetic resonance analyses in combination with metabolite balancing, the in vivo activities for pathways or single enzymes in the central metabolism of C. glutamicum were quantified for growth on acetate, on glucose, and on both carbon sources. The activity of the citric acid cycle was high on acetate, intermediate on acetate plus glucose, and low on glucose, corresponding to in vivo activities of citrate synthase of 413, 219, and 111 nmol. (mg of protein)(-1). min(-1), respectively. The citric acid cycle was replenished by carboxylation of phosphoenolpyruvate (PEP) and/or pyruvate (30 nmol. [mg of protein](-1). min(-1)) during growth on glucose. Although levels of PEP carboxylase and pyruvate carboxylase during growth on acetate were similar to those for growth on glucose, anaplerosis occurred solely by the glyoxylate cycle (99 nmol. [mg of protein](-1). min(-1)). Surprisingly, the anaplerotic function was fulfilled completely by the glyoxylate cycle (50 nmol. [mg of protein](-1). min(-1)) on glucose plus acetate also. Consistent with the predictions deduced from the metabolic flux analyses, a glyoxylate cycle-deficient mutant of C. glutamicum, constructed by targeted deletion of the isocitrate lyase and malate synthase genes, exhibited impaired growth on acetate-glucose mixtures. (+info)
Encrusted pyelitis of native kidneys.
(43/951)
This study reports the first four cases of encrusted pyelitis involving native kidneys. The clinical features, management, and outcome of these patients were analyzed. Predisposing factors were underlying urologic disease and/or urologic manipulations, debilitating diseases, hospitalization, and prolonged antibiotic therapies. Presenting symptoms were renal failure in three patients with ureteroileal urinary diversion and manifestations of cystitis in one patient. Computed tomography scan of the urinary tract was critical for diagnosis. Presence of struvite was demonstrated by crystalluria and infrared spectrophotometry analysis of the encrusted material. Corynebacterium urealyticum urinary infection was identified in one case. Surgery (one patient) and palliative ureteral diversion (one patient), respectively, led to death and end-stage renal failure. Successful dissolution of encrusted pyelitis was obtained in two patients treated with intravenous vancomycin and local acidification of the renal collecting system. Clinical observation shows that encrusted pyelitis is a threatening disorder that destroys the native kidneys and may lead to end-stage renal failure. Successful treatment of the disease by chemolysis and antibiotics depends on correct and early diagnosis. Diagnosis required recognition of the predisposing factors, computed tomography imaging of the urinary tract, crystalluria, and identification of urea-splitting bacteria with prolonged culture on selective medium. (+info)
Corynebacterium simulans sp. nov., a non-lipophilic, fermentative Corynebacterium.
(44/951)
Three coryneform strains isolated from clinical samples were analysed. These strains fitted the biochemical profile of Corynebacterium striatum by conventional methods. However, according to recently described identification tests for fermenting corynebacteria, the strains behaved rather like Corynebacterium minutissimum. The three isolates could be distinguished from C. minutissimum by a positive nitrate and nitrite reductase test and by not fermenting maltose; from C. striatum by their inability to acidify ethylene glycol and to grow at 20 degrees C. Genetic studies based on 16S rRNA showed that the three strains were in fact different from C. minutissimum and C. striatum (96.9 and 98% similarity, respectively) and from other corynebacteria. They represent a new species for which the name Corynebacterium simulans sp. nov. is proposed. The type strain is DSM 44415T (= UCL 553T = Co 553T). (+info)
Development of an improved assay for purine nucleoside kinase activity in cell extracts and detection of inosine kinase activity in Brevibacterium acetylicum ATCC 953, related species, and Corynebacterium flaccumfaciens ATCC 6887.
(45/951)
An improved assay was developed to detect direct purine nucleoside phosphorylating activity in cell-free extracts. Direct inosine phosphorylating activity was detected in 2 of 70 species tested. Both activities, which depended on magnesium ion and ATP, phosphorylated a hydroxyl group at the 5' position of inosine. The new assay was shown to be useful for screening of direct purine nucleoside phosphorylating activity and have the potential to detect inosine kinase in the presence of a background of nucleoside phosphorylase and purine phosphoribosyltransferase activities. Previously, the latter two activities made it difficult to correctly detect direct phosphorylation of inosine by inosine kinase. (+info)
Kinetic properties of the glucose-6-phosphate and 6-phosphogluconate dehydrogenases from Corynebacterium glutamicum and their application for predicting pentose phosphate pathway flux in vivo.
(46/951)
The glucose-6-phosphate (Glc6P) and 6-phosphogluconate (6PG) dehydrogenases of the amino-acid-producing bacterium Corynebacterium glutamicum were purified to homogeneity and kinetically characterized. The Glc6P dehydrogenase was a heteromultimeric complex, which consists of Zwf and OpcA subunits. The product inhibition pattern of the Glc6P dehydrogenase was consistent with an ordered bi-bi mechanism. The 6PG dehydrogenase was found to operate according to a Theorell-Chance ordered bi-ter mechanism. Both enzymes were inhibited by NADPH and the 6PG dehydrogenase additionally by ATP, fructose 1,6-bisphosphate (Fru1,6P2), D-glyceraldehyde 3-phosphate (Gra3P), erythrose 4-phosphate and ribulose 5-phosphate (Rib5P). The inhibition by NADPH was considered to be most important, with inhibition constants of around 25 microM for both enzymes. Intracellular metabolite concentrations were determined in two isogenic strains of C. glutamicum with plasmid-encoded NAD- and NADP-dependent glutamate dehydrogenases. NADP+ and NADPH levels were between 130 microM and 290 microM, which is very much higher than the respective Km and Ki values. The Glc6P concentration was around 500 microM in both strains. The in vivo fluxes through the oxidative part of the pentose phosphate pathway calculated on the basis of intracellular metabolite concentrations and the kinetic constants of the purified enzymes determined in vitro were in agreement with the same fluxes determined by NMR after 13C-labelling. From the derived kinetic model thus validated, it is concluded that the oxidative pentose phosphate pathway in C. glutamicum is mainly regulated by the ratio of NADPH and NADP+ concentrations and the specific enzyme activities of both dehydrogenases. (+info)
Cloning of the malic enzyme gene from Corynebacterium glutamicum and role of the enzyme in lactate metabolism.
(47/951)
Malic enzyme is one of at least five enzymes, known to be present in Corynebacterium glutamicum, capable of carboxylation and decarboxylation reactions coupling glycolysis and the tricarboxylic acid cycle. To date, no information is available concerning the physiological role of the malic enzyme in this bacterium. The malE gene from C. glutamicum has been cloned and sequenced. The protein encoded by this gene has been purified to homogeneity, and the biochemical properties have been established. Biochemical characteristics indicate a decarboxylation role linked to NADPH generation. Strains of C. glutamicum in which the malE gene had been disrupted or overexpressed showed no detectable phenotype during growth on either acetate or glucose, but showed a significant modification of growth behavior during lactate metabolism. The wild type showed a characteristic brief period of exponential growth on lactate followed by a linear growth period. This growth pattern was further accentuated in a malE-disrupted strain (Delta malE). However, the strain overexpressing malE maintained exponential growth until all lactate had been consumed. This strain accumulated significantly larger amounts of pyruvate in the medium than the other strains. (+info)
Purification of alginate oligosaccharides with root growth-promoting activity toward lettuce.
(48/951)
Sodium alginate was degraded by alginate lyase from Corynebacterium sp., and the product was purified by an ultrafiltration (UF) membrane module. The UF treatment was carried out at a transmembrane pressure of 0.15 MPa and a flow velocity of 0.6 m/s in the cross-flow mode, and non-degraded alginate was almost completely removed. The alginate oligosaccharide obtained was a mixture of di- to octasaccharides and had promoting activity toward lettuce root elongation (about 2-fold compared with the control) in the concentration range of 200-3000 microg/ml. The effect of the degree of polymerization on this activity was examined by using each oligosaccharide fractionated by gel chromatography. The tri-, tetra-, penta- and hexasaccharides were each found to have root growth-promoting activity in a lettuce bioassay. (+info)