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PubMed1983

Calcium gluconate pretreatment for prevention of succinylcholine-induced myalgia.

The effects of calcium gluconate pretreatment on succinylcholine-induced postoperative muscle pain and on the changes in serum potassium and calcium levels were studied in 80 patients undergoing elective surgery who were to become ambulatory on the same evening. A test group of 40 patients was given 10 ml of 10% calcium gluconate intravenously immediately before induction of anesthesia with thiopental followed by succinylcholine for tracheal intubation. A control group of 40 patients was given thiopental and succinylcholine without calcium gluconate. Muscle pains were graded according to severity as nil, mild, moderate, and severe. The incidence of postoperative muscle pains was significantly less (5%) in the test group than in the control group (45%). In control patients who subsequently developed muscle pain, serum levels of potassium were significantly increased above preinduction levels 2 min after succinylcholine was administered and serum calcium levels were significantly decreased. In control patients who did not develop postoperative myalgia, there were no significant changes in serum levels of either calcium or potassium. This was also true for patients pretreated with calcium gluconate. Therefore, calcium gluconate pretreatment reduces both the increase in serum potassium and the decrease in serum calcium associated with succinylcholine, and decreases the incidence and severity of postoperative myalgia.

Adolescent↗
PubMed2001

Involvement of gntS in the control of GntI, the main system for gluconate metabolism in Escherichia coli.

The initial steps of gluconate metabolism in E. coli, transport and phosphorylation, occur through duplicate activities. These activities have been included in two systems designated as GntI (main) and GntII (subsidiary), encoded by differently regulated operons located at the 76.4-77 and 95.3-96.9 regions on the map respectively. Despite recent molecular advances related to genetics and physiology of these systems, there is no information about the coordination of their expression when E. coli grows on gluconate. Under these conditions, the subsidiary gluconokinase (gntV gene, min 96.8) as well as the GntI activities are expressed in inducible form. Therefore it was of interest to find out if GntS, the positive regulator of gntV has a similar effect on GntI activities expression. Our results agree with this hypothesis. GntS, in addition to its regulatory action on the gntV gene, seems to assist, direct or indirectly, the expression of the GntI activities. A gntS E. coli mutant does not grow on gluconate but spontaneously pseudoreverts to a gluconate growing phenotype at high rate per cell generation when cultivated in rich media with or without gluconate or mineral medium containing any other suitable carbon source. In the pseudorevertants, the thermosensitive gluconokinase remains repressed while the GntI activities are inducibly expressed. At present, the location and nature of the gntS suppressor mutation are not known. Phage P1Kc mediated transductions have ruled out that it alters the gntT gene. This is the first report on GntI activities alteration due to a lesion located out of the bioH-asd region.

Bacterial Proteins↗
PubMed1997

The metabolism of gluconate in Escherichia coli. The subsidiary system and the nature of the gntS gene.

The transport and phosphorylation of gluconate in E. coli occurs through two systems (GntI and GntII) which duplicate activities. bioH-asd deletion mutants do not grow on media with gluconate as sole carbon source because they lack the GntI system and do not express GntII. Although E. coli c177 is a delta (bioH-asd) mutant, it carries the pyrB linked mutation gnt177 that enables it to metabolize this substrate through inducible expression of the GntII system. Several gntS derivatives which are unable to grow on gluconate were isolated from E. coli C177 by spontaneous curing of the transposon Tn10 previously inserted at the gntS locus (zjf::Tn10, min 95.3). A representative gntS mutant, E. coli TI141A retained the ability to take up gluconate but had lost the thermosensitive gluconokinase activity (gene gntV, min 96.9). Furthermore, it could be demonstrated that gntV is repressed in E. coli TI141A. The results indicate that gntS might specify a trans-acting positive regulator involved in the control of at least the expression of the thermosensitive gluconokinase (GntII), instead of a gluconate uptake system as it was previously postulated. Likewise, these results can be used to reconsider whether the locus altered by the gnt177 lesion is allelic with that of the GntII permease instead of a regulator, as it was originally postulated.

Alleles↗
PubMed2004

Gluconic acid production in bioreactor with immobilized glucose oxidase plus catalase on polymer membrane adjacent to anion-exchange membrane.

Gluconic acid was obtained in the permeate side of the bioreactor with glucose oxidase (GOD) immobilized onto anion-exchange membrane (AEM) of low-density polyethylene grafted with 4-vinylpiridine. The electric resistance of the anion-exchange membranes was increased after the enzyme immobilization on the membrane. The gluconic acid productions were relatively low with the GOD immobilized by any method on the AEM. To increase the enzyme reaction efficiency, GOD was immobilized on membrane of AN copolymer (PAN) adjacent to an anion-exchange membrane in bioreactor. Uses of anion-exchange membrane led to selective removal of the gluconic acid from the glucose solution and reduce the gluconic acid inhibition. The amount of gluconic acid obtained in the permeate side of the bioreactor with the GOD immobilized on the PAN membrane adjacent to the AEM under electrodialysis was about 30 times higher than that obtained with enzyme directly bound to the AEM. The optimal substrate concentration in the feed side was found to be about 1 g/l. Further experiments were carried out with the co-immobilized GOD plus Catalase (CAT) on the PAN membrane adjacent to the AEM to improve the efficiency of the immobilize system. The yield of this process was at least 95%. The storage stability of the co-immobilized GOD and CAT was studied (lost 20% of initial activity for 90 d). The results obtained clearly showed the higher potential of the dual membrane bioreactor with GOD plus CAT bound to ultrafiltration polymer membrane adjacent to the AEM. Storage stability of GOD activity in GOD plus CAT immobilized on PAN//AEM membranes and on AEM.

Acetobacter↗
PubMed1997

Gene organization and transcriptional regulation of the gntRKU operon involved in gluconate uptake and catabolism of Escherichia coli.

We cloned and characterized the gntRKU operon encoding part of the GntI system involved in gluconate uptake and catabolism by Escherichia coli. The operon was shown to encode its repressor, a thermoresistant gluconate kinase, and a low affinity gluconate permease. CAT fusion analysis revealed that the operon has a promoter for gntR and another for gntKU, and that the gntR gene is constitutively expressed, while that of gntKU is regulated positively by the cAMP-CRP complex and negatively by GntR. Read-through transcription from the gntR promoter into gntK was decreased in the presence of GntR, although GntR did not repress its own promoter. In addition, transcriptional attenuation was observed after the gntK gene, so gntU expression is reduced presumably to modulate the production of the low affinity gluconate permease according to the available concentration of gluconate.

Amino Acid Sequence↗
PubMed1983

Binding of 99mTc-gluconate to heart mitochondria.

99mTc-gluconate has previously been shown to bind to isolated rat heart mitochondria. In the presence of potassium cyanide this binding is enhanced several fold, an effect which has been shown to be correlated to the efficiency of the in vivo binding of the isotope complex in ischemic dog hearts. The present investigation shows that the potassium cyanide-induced binding was mainly localized to the mitochondrial inner membrane; in the presence of cyanide other organelles, e.g., nuclei and liver microsomes also showed some binding. Boiling, lipid extraction, or addition of N-ethylmaleimide caused a variable inhibition of the binding of 99mTc-gluconate to rat heart mitochondria, which also was markedly influenced by temperature, pH, time, and concentrations of protein and isotope complex, but not by conditions affecting energy levels or calcium transport. Fractionation of submitochondrial particles exposed to 99mTc-gluconate in the presence of potassium cyanide indicated that the 99mTc-gluconate-binding component cofractionated with cytochrome oxidase. It is postulated that a protein component localized in the mitochondrial inner membrane, possibly cytochrome oxidase, is responsible for the binding of 99mTc-gluconate.

Animals↗
PubMed1994

Influence of intravenous calcium gluconate on saphenous vein graft flow in closed-chest patients.

The effects of calcium gluconate on hemodynamics and saphenous vein graft flow in a group of patients undergoing elective coronary artery bypass grafting who developed ionized hypocalcemia at the end of the surgical procedure were examined. The patients received a central venous bolus of 15 mg/kg of calcium gluconate. Heart rate (HR), arterial pressure (AP), central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output were measured immediately before and 30, 60, 120, 180, and 240 seconds after injection of calcium gluconate. Systemic and pulmonary vascular resistance (SVR and PVR, respectively), cardiac index (CI), stroke volume index (SVI), and right and left ventricular stroke work index (RVSWI and LVSWI, respectively), were calculated. Venous bypass flow velocity (Vbypass-flow) was assessed using a Doppler probe that was attached to the left anterior descending artery (LAD) bypass intraoperatively. Calcium gluconate significantly increased MAP, SVR, and LVSWI from 67 +/- 3 mmHg (mean +/- SEM), 1,128 +/- 128 dyne.s.cm-5 and 25 +/- 3 g.m.beat/m to a maximum of 81 +/- 5 mmHg (P < 0.01), 1,401 +/- 196 dyne.s.cm-5 (P < 0.05), and 32 +/- 4 g.m/beat/m (P < 0.01), respectively. HR, CVP, PAP, PCWP, PVR, CI, SVI, and Vbypass-flow remained unaltered. It is concluded that calcium gluconate administered to moderately hypocalcemic patients increases arterial pressure mainly by peripheral vasoconstriction. Because the increase of arterial pressure, and, thereby, coronary perfusion pressure is not associated with an increase of LAD bypass flow, vasoconstriction in the coronary vascular bed distal to the venous graft cannot be ruled out, and deterioration of the myocardial oxygen supply/demand ratio is strongly suggested.

Aged↗
PubMed1994

Specific transfer of 3H from D-[3-3H]gluconic acid into L-tartaric acid in vitaceous plants.

Transfer of 3H from D-gluconic acid, specifically labelled with 3H at C-2 or C-3 and 14C at C-1, C-2, or C-3, 4, to L(+)-tartaric acid was examined in leaves and berries of Vitis labrusca cv Delaware and in leaves of Parthenocissus quinquefolia. 3H located at C-3 of D-gluconic acid was highly conserved in this transfer, yielding a 3H/14C ratio between 3.3 and 14 in the light and between 11 and 22 in the dark. These experiments strongly suggest that a portion of the 3H present in L(+)-tartaric acid may have been transferred from D-gluconic acid to L(+)-tartaric acid, possibly via NADP[3H] through a redox process involving reduction of L-xylo-2-hexulosonate (2-keto-L-idonate). Both [3H]-tartaric acid and [14C]tartaric acid synthesized in grape leaves from D-[3-3H, 2-14C]gluconic acid, or [3-3H, 3,4-14C]gluconic acid were characterized as L(+)-chiral form exclusively, the naturally occurring from of tartaric acid.

Fruit↗
PubMed2006

13C-labeled gluconate tracing as a direct and accurate method for determining the pentose phosphate pathway split ratio in Penicillium chrysogenum.

In this study we developed a new method for accurately determining the pentose phosphate pathway (PPP) split ratio, an important metabolic parameter in the primary metabolism of a cell. This method is based on simultaneous feeding of unlabeled glucose and trace amounts of [U-13C]gluconate, followed by measurement of the mass isotopomers of the intracellular metabolites surrounding the 6-phosphogluconate node. The gluconate tracer method was used with a penicillin G-producing chemostat culture of the filamentous fungus Penicillium chrysogenum. For comparison, a 13C-labeling-based metabolic flux analysis (MFA) was performed for glycolysis and the PPP of P. chrysogenum. For the first time mass isotopomer measurements of 13C-labeled primary metabolites are reported for P. chrysogenum and used for a 13C-based MFA. Estimation of the PPP split ratio of P. chrysogenum at a growth rate of 0.02 h(-1) yielded comparable values for the gluconate tracer method and the 13C-based MFA method, 51.8% and 51.1%, respectively. A sensitivity analysis of the estimated PPP split ratios showed that the 95% confidence interval was almost threefold smaller for the gluconate tracer method than for the 13C-based MFA method (40.0 to 63.5% and 46.0 to 56.5%, respectively). From these results we concluded that the gluconate tracer method permits accurate determination of the PPP split ratio but provides no information about the remaining cellular metabolism, while the 13C-based MFA method permits estimation of multiple fluxes but provides a less accurate estimate of the PPP split ratio.

Carbon Isotopes↗
PubMed1999

Production of medium-chain-length poly(3-hydroxyalkanoates) from gluconate by recombinant Escherichia coli.

It was shown recently that recombinant Escherichia coli, defective in the beta-oxidation cycle and harboring a medium-chain-length (MCL) poly(3-hydroxyalkanoate) (PHA) polymerase-encoding gene of Pseudomonas, is able to produce MCL PHA from fatty acids but not from sugars or gluconate (S. Langenbach, B. H. A. Rehm, and A. Steinbüchel, FEMS Microbiol. Lett. 150:303-309, 1997; Q. Ren, Ph.D. thesis, ETH Zürich, Zürich, Switzerland, 1997). In this study, we report the formation of MCL PHA from gluconate by recombinant E. coli. By introduction of genes coding for an MCL PHA polymerase and the cytosolic thioesterase I ('thioesterase I) into E. coli JMU193, we were able to engineer a pathway for the synthesis of MCL PHA from gluconate. We used two expression systems, i.e., the bad promoter and alk promoter, for the 'thioesterase I- and PHA polymerase-encoding genes, respectively, which enabled us to modulate their expression independently over a range of inducer concentrations, which resulted in a maximum MCL PHA accumulation of 2.3% of cell dry weight from gluconate. We found that the amount of PHA and the 'thioesterase I activity are directly correlated. Moreover, the polymer accumulated in the recombinant E. coli consisted mainly of 3-hydroxyoctanoate monomers. On the basis of our data, we propose an MCL PHA biosynthesis pathway scheme for recombinant E. coli JMU193, harboring PHA polymerase and 'thioesterase I, when grown on gluconate, which involves both de novo fatty acid synthesis and beta-oxidation.

Acyltransferases↗
PubMed1973

Regulatory mutations affecting the gluconate system in Escherichia coli.

A spontaneously arising regulatory mutant of the gluconate system in Escherichia coli was isolated. This mutant became constitutive, probably in one step, for gluconate high-affinity transport, gluconokinase, and gluconate-6-P dehydrase. The mutation involved (gntR18) is cotransducible with asd. Pseudorevertants, derived from a mutant (M2) that shows a long lag for growth on gluconate mineral medium, were also isolated and characterized. They give constitutive levels of gluconokinase and gluconate-6-P dehydrase but lack high-affinity transport function. Genetic experiments performed with one of these pseudorevertants (M4) indicate that it carries a secondary mutation in the gntR gene. The M4 phenotype is thus the result of the interaction of expression of a constitutive mutation (gntR4) with the mutation of strain M2 (gntM2).

Aerobiosis↗
PubMed1995

Biochemical characterization and sequence analysis of the gluconate:NADP 5-oxidoreductase gene from Gluconobacter oxydans.

Gluconate:NADP 5-oxidoreductase (GNO) from the acetic acid bacterium Gluconobacter oxydans subsp. oxydans DSM3503 was purified to homogeneity. This enzyme is involved in the nonphosphorylative, ketogenic oxidation of glucose and oxidizes gluconate to 5-ketogluconate. GNO was localized in the cytoplasm, had an isoelectric point of 4.3, and showed an apparent molecular weight of 75,000. In sodium dodecyl sulfate gel electrophoresis, a single band appeared corresponding to a molecular weight of 33,000, which indicated that the enzyme was composed of two identical subunits. The pH optimum of gluconate oxidation was pH 10, and apparent Km values were 20.6 mM for the substrate gluconate and 73 microM for the cosubstrate NADP. The enzyme was almost inactive with NAD as a cofactor and was very specific for the substrates gluconate and 5-ketogluconate. D-Glucose, D-sorbitol, and D-mannitol were not oxidized, and 2-ketogluconate and L-sorbose were not reduced. Only D-fructose was accepted, with a rate that was 10% of the rate of 5-ketogluconate reduction. The gno gene encoding GNO was identified by hybridization with a gene probe complementary to the DNA sequence encoding the first 20 N-terminal amino acids of the enzyme. The gno gene was cloned on a 3.4-kb DNA fragment and expressed in Escherichia coli. Sequencing of the gene revealed an open reading frame of 771 bp, encoding a protein of 257 amino acids with a predicted relative molecular mass of 27.3 kDa. Plasmid-encoded gno was functionally expressed, with 6.04 U/mg of cell-free protein in E. coli and with 6.80 U/mg of cell-free protein in G. oxydans, which corresponded to 85-fold overexpression of the G. oxydans wild-type GNO activity. Multiple sequence alignments showed that GNO was affiliated with the group II alcohol dehydrogenases, or short-chain dehydrogenases, which display a typical pattern of six strictly conserved amino acid residues.

Amino Acid Sequence↗
PubMed1996

The gntP gene of Escherichia coli involved in gluconate uptake.

The gntP gene, located between the fim and uxu loci in Escherichia coli K-12, has been cloned and characterized. Nucleotide sequencing of a region encompassing the gntP gene revealed an open reading frame of 447 codons with significant homology to the Bacillus subtilis gluconate permease. Northern (RNA) blotting indicated that the gntP gene was monocistronic and was transcribed as an mRNA with an apparent molecular size of 1.54 kb. The transcriptional start point was determined by primer extension analysis. The gntP gene was found to be under catabolite repression and was not induced by gluconate. Also, expression seemed to be stringently controlled. Several observations indicated that the GntP protein is an inner membrane protein; it contains characteristic membrane-spanning regions and was isolated predominantly from the inner-membrane fraction of fractionated host cells. A topology analysis predicted a protein with 14 membrane-spanning segments. The inability of a mutant strain to grow on gluconate minimal medium could be relieved by introduction of a plasmid encoding the gntP gene. Finally, the kinetics of GntP-mediated gluconate uptake were investigated, indicating an apparent Km for gluconate of 25 microM.

Amino Acid Sequence↗
PubMed2003

The activator of GntII genes for gluconate metabolism, GntH, exerts negative control of GntR-regulated GntI genes in Escherichia coli.

Gluconate is one of the preferred carbon sources of Escherichia coli, and two sets of gnt genes (encoding the GntI and GntII systems) are involved in its transport and metabolism. GntR represses the GntI genes gntKU and gntT, whereas GntH was previously suggested to be an activator for the GntII genes gntV and idnDO-gntWH. The helix-turn-helix residues of the two regulators GntR and GntH exhibit extensive homologies. The similarity between the two regulators prompted analysis of the cross-regulation of the GntI genes by GntH. Repression of gntKU and gntT by GntH, as well as GntR, was indeed observed using transcriptional fusions and RNA analysis. High GntH expression, from cloned gntH or induced through 5-ketogluconate, was required to observe repression of GntI genes. Two GntR-binding elements were identified in the promoter-operator region of gntKU and were also shown to be the target sites of GntH by mutational analysis. However, the GntI genes were not induced by gluconate in the presence of enhanced amounts of GntH, whereas repression by GntR was relieved by gluconate. The repression of GntI genes by GntH is thus unusual in that it is not relieved by the availability of substrate. These results led us to propose that GntH activates GntII and represses the GntI genes in the presence of metabolites derived from gluconate, allowing the organism to switch from the GntI to the GntII system. This cross-regulation may explain the progressive changes in gnt gene expression along with phases of cell growth in the presence of gluconate.

Amino Acid Sequence↗
PubMed1962

Dissimilation of glucose and gluconic acid by Pseudomonas natriegens.

Eagon, R. G. (University of Georgia, Athens) and C. H. Wang. Dissimilation of glucose and gluconic acid by Pseudomonas natriegens. J. Bacteriol. 83:879-886. 1962-When glucose dissimilation of a marine pseudomonad, Pseudomonas natriegens, was studied, enzymes of both the glycolytic pathway and of the hexose monophosphate pathway were detected in extracts of glucose-grown cells. Enzymes of the Entner-Doudoroff pathway and phosphoketolase were not detected. Data from radiorespirometric experiments indicated that approximately 92 and 8% of glucose actually catabolized were routed via the glycolytic and the hexose monophosphate pathways, respectively. When P. natriegens was induced to utilize gluconate, it was demonstrated that gluconokinase and enzymes of the Entner-Doudoroff pathway were induced. Radiorespirometric experiments with cells under growing conditions revealed that gluconate was dissimilated predominantly (80%) via the Entner-Doudoroff pathway. This observation was in contrast to the observation that the glycolytic pathway is practically the exclusive catabolic pathway for glucose dissimilation. A minor portion of substrate gluconate was also catabolized by this organism via the hexosemonophosphate pathway. However, the pentose phosphate derived from substrate gluconate is believed not to be catabolized extensively.The important facet uncovered by these experiments was the extensive operation of the glycolytic route of glucose dissimilation. This is in contrast to other pseudomonads studied to date, which have been reported to dissimilate glucose predominantly via the Entner-Doudoroff pathway and which do not utilize the glycolytic pathway.

Gluconates↗
PubMed1968

Selection of Escherichia coli mutants lacking glucose-6-phosphate dehydrogenase or gluconate-6-phosphate dehydrogenase.

Glucose is metabolized in Escherichia coli chiefly via the phosphoglucose isomerase reaction; mutants lacking that enzyme grow slowly on glucose by using the hexose monophosphate shunt. When such a strain is further mutated so as to yield strains unable to grow at all on glucose or on glucose-6-phosphate, the secondary strains are found to lack also activity of glucose-6-phosphate dehydrogenase. The double mutants can be transduced back to glucose positivity; one class of transductants has normal phosphoglucose isomerase activity but no glucose-6-phosphate dehydrogenase. An analogous scheme has been used to select mutants lacking gluconate-6-phosphate dehydrogenase. Here the primary mutant lacks gluconate-6-phosphate dehydrase (an enzyme of the Enter-Doudoroff pathway) and grows slowly on gluconate; gluconate-negative mutants are selected from it. These mutants, lacking the nicotinamide dinucleotide phosphate-linked glucose-6-phosphate dehydrogenase or gluconate-6-phosphate dehydrogenase, grow on glucose at rates similar to the wild type. Thus, these enzymes are not essential for glucose metabolism in E. coli.

Escherichia coli↗
PubMed2005

Participation of the Entner-Doudoroff pathway in Escherichia coli strains with an inactive phosphotransferase system (PTS- Glc+) in gluconate and glucose batch cultures.

The activity of the enzymes of the central metabolic pathways has been the subject of intensive analysis; however, the Entner-Doudoroff (ED) pathway has only recently begun to attract attention. The metabolic response to edd gene knockout in Escherichia coli JM101 and PTS- Glc+ was investigated in gluconate and glucose batch cultures and compared with other pyruvate kinase and PTS mutants previously constructed. Even though the specific growth rates between the strain carrying the edd gene knockout and its parent JM101 and PTS- Glc+ edd and its parent PTS- Glc+ were very similar, reproducible changes in the specific consumption rates and biomass yields were obtained when grown on glucose. These results support the participation of the ED pathway not only on gluconate metabolism but on other metabolic and biochemical processes in E. coli. Despite that gluconate is a non-PTS carbohydrate, the PTS- Glc+ and derived strains showed important reductions in the specific growth and gluconate consumption rates. Moreover, the overall activity of the ED pathway on gluconate resulted in important increments in PTS- Glc+ and PTS- Glc+ pykF mutants. Additional results obtained with the pykA pykF mutant indicate the important contribution of the pyruvate kinase enzymes to pyruvate synthesis and energy production in both carbon sources.

Aldehyde-Lyases↗
PubMed2001

Substrate selectivity of Gluconobacter oxydans for production of 2,5-diketo-D-gluconic acid and synthesis of 2-keto-L-gulonic acid in a multienzyme system.

Substrate selectivity of Gluconobacter oxydans (ATCC 9937) for 2,5-diketo-D-gluconic acid (2,5-DKG) production was investigated with glucose, gluconic acid, and gluconolactone in different concentrations using a resting-cell system. The results show that gluconic acid was utilized favorably by G. oxydans as substrate to produce 2,5-DKG. The strain was coupled with glucose dehydrogenase (GDH) and 2,5-DKG reductase for synthesis of 2-keto-L-gulonic acid (2-KLG), a direct precursor of L-ascorbic acid, from glucose. NADP and NADPH were regenerated between GDH and 2,5-DKG reductase. The mole yield of 2-KLG of this multienzyme system was 16.8%. There are three advantages for using the resting cells of G. oxydans to connect GDH with 2,5-DKG reductase for production of 2-KLG: gluconate produced by GDH may immediately be transformed into 2,5-DKG so that a series of problems generally caused by the accumulation of gluconate would be avoided; 2,5-DKG is supplied directly and continuously for 2,5-DKG reductase, so it is unnecessary to take special measures to deal with this unstable substrate as it was in Sonoyama's tandem fermentation process; and NADP(H) was regenerated within the system without any other components or systems.

Gluconates↗