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A DNA fragment containing the promoter of the Bacillus subtilis gluconate (gnt) operon and its first gene (gntR) was cloned into Escherichia coli. E. coli recognized this promoter efficiently and precisely. Moreover, the gluconate-inducible system of this operon operated even in E. coli.
Mortlock, R. P. (U.S. Army Chemical Corps, Frederick, Md.). Gluconate metabolism of Pasteurella pestis. J. Bacteriol. 84:53-59. 1962.-During a study of gluconate metabolism by a virulent strain of Pasteurella pestis, evidence was obtained for the presence of gluconokinase, 6-phosphogluconate dehydrogenase, transketolase, and 2-keto-3-deoxy-6-phosphogluconate dehydrase in cell-free extracts. A study of the products of 6-phosphogluconate degradation by extracts indicated that 6-phosphogluconate was metabolized by both the 6-phosphogluconate dehydrogenase-transketolase pathway and the Entner-Doudoroff pathway. No evidence could be obtained for the presence of an active glucose-6-phosphate dehydrogenase.
Immobilization of Zymomonas mobilis by different methods was investigated. Experiments were performed in order to choose the most appropriate support for the immobilization of the cells. The most advantageous option was to use permeabilized cells in the bore of microporous hollow fibers. Whereas the reaction rate was about 33 g of gluconate/(g of protein x h) using hollow fibers, which is comparable to that observed by using free cells, the calcium alginate immobilized cells presented a reaction rate of 4 g of gluconate/(g of protein x h). These results can be explained by the mass transfer resistance effect, which, indeed, was much lower in the case of hollow-fiber membranes than in the alginate gel beads. A loss of enzymatic activity during the reaction was observed in all experiments, which was attributed to the lactone produced as an intermediate of the reaction.
Twenty-four strains of Escherichia coli from the ECOR collection were characterized for growth rate in gluconate minimal salts medium and for Vmax and Km of the three enzymes (gluconokinase, 6-phosphogluconate dehydrogenase, and 6-phosphogluconate dehydratase) that form a branch point for the utilization of gluconate. A total of 11 characters--growth rate, three Vmax values, four Km values, and three Vmax/Km values--were determined for these 24 ECOR strains. Most of the characters were normally distributed. Statistical tests showed that growth rate is significantly less variable than enzyme activities. Also, analyses of variance showed significant differences among strains and among the extant five genetic groups of E. coli for the characters measured. A Mantel test showed that, for some characters, closely related strains shared similar character values. Two hypotheses regarding the relationships between growth rate and enzyme activity and between various enzyme activities were tested. None of the expected correlations between growth rate and enzyme activity or between enzyme activities was detected. The results were discussed in terms of metabolic control analysis and neutral theory.
Yeast extract-iron-gluconic acid-dihydroxyacetone-serum medium that allows axenic cultivation of Entamoeba dispar was designed based on casein-free yeast extract-iron-serum (YI-S) medium, and the usefulness of the medium was assessed. The main differences from YI-S medium are replacement of glucose by gluconic acid, addition of dihydroxyacetone and D-galacturonic acid monohydrate, and sterilization by filtration. This medium promoted the axenic growth of 5 strains of E. dispar (2 strains of nonhuman primate isolates and 3 strains of human isolates). In addition, to clarify the biological basis for the growth of E. dispar in this medium, analyses of relevant enzymes on the glycolytic pathway of the amoebae as well as of the protozoans that are the best culture supplement for amoebae are being performed.
BACKGROUND: The most frequent causes of upper respiratory infections are human rhinoviruses. The nasopharyngeal area, which includes the respiratory epithelium, mucosa, and the olfactory neuroepithelium (ONe), is a first-line of defense against airborne viruses and allergens, some of which manage to penetrate the nasal mucosa and invade the tissues of the nasal respiratory epithelium. Biochemical evidence from several studies suggests that zinc is an effective cold treatment and that over-the-counter (OTC) zinc-gluconate compounds may provide the high pharmacologic doses of zinc needed to act as an effective means of treating and reducing the duration and severity of symptoms of the common cold. METHODS: A series of male Sprague-Dawley rats were fed an oral preparation of zinc-gluconate trihydrate or received the equivalent through drinking water to investigate the potential cytotoxic and/or neurotoxic insult to the olfactory receptor cells and other tissue in the ONe and afferent neuronal pathways. RESULTS: Coronal sections of the rat ONe and corresponding olfactory bulbs showed consistent cellular and tissue damage of increasing severity that correlated with the duration of treatment with the zinc compound when compared with the control group animals. CONCLUSION: The results of this analysis indicate that the repeated oral administration of such zinc-containing compounds have neurotoxic effects on the ONe and to the mitral cells in the olfactory bulbs of treated rats. These findings point toward the need for increased investigation into the potential deleterious effects of zinc-containing compounds to humans as well.
Gluconic acid (GA) derives from the incomplete oxidation of glucose by some Gluconobacter strains. When fed to nonruminant animals, GA is only poorly absorbed in the small intestine and is primarly fermented to butyric acid in the lower gut. This study investigated the effect of GA on in vitro growth response and metabolism of swine cecal microflora and on animal growth performance, intestinal wall morphology, and intestinal microflora. During a 24-h in vitro cecal fermentation, total gas production and maximum rate of gas production were increased by GA (linear, P < 0.001). Ammonia in cecal liquor was reduced by GA after 4, 8, and 24 h of fermentation (quadratic, P < 0.01). After 24 h of fermentation, total short-chain fatty acids, acetic acid, propionic acid, n-butyric acid, acetic to propionic acid ratio, and acetic + butyric to propionic acid ratio were linearly increased by GA (P < 0.001). In the in vivo study, 48 piglets were divided into 4 groups and housed in individual cages for 6 wk. Piglets received a basal diet with a) no addition (control) or with GA addition at b) 3,000 ppm, c) 6,000 ppm, or d) 12,000 ppm. After 6 wk, 4 animals per treatment were killed, and samples of intestinal content and mucosa were collected. Compared with control, GA tended to increase average daily gain (+13 and +14% for GA at 3,000 and 6,000 ppm, respectively; P of the model = 0.11; quadratic, P < 0.05). Daily feed consumption and gain to feed ratio were not influenced by GA. Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria were not affected by GA. Gluconic acid tended to increase total short-chain fatty acids in the jejunum (+174, +87, and +74% for GA at 3,000, 6,000, and 12,000 ppm, respectively; P of the model = 0.07; quadratic, P = 0.07). Morphological evaluation of intestinal mucosa from jejunum, ileum, and cecum did not show any significant differences among treatments. This study showed that feeding GA influences the composition and activity of the intestinal microflora and may improve growth performance of piglets after weaning.
Binding of 99Tcm-gluconate on the subcellular level in myocardial infarct tissue in the dog was investigated by means of a fractionated centrifugation technique. High isotope activity/g protein was recorded in the mitochondrial fraction indicating the 99Tcm-gluconate binds preferentially to a protein structure localized in the mitochondria.
We report a case in which acute digital hydrofluoric acid burns were treated with regional intravenous perfusion of calcium gluconate to relieve pain and protect from further tissue damage. This is the first documented instance of this technique being used. The conventional treatments for digital hydrofluoric acid burns all have their shortcomings; intravenous regional perfusion of calcium gluconate may be an effective method of treatment for digital hydrofluoric acid burns.
CASE REPORT: Despite the popularity of zinc gluconate for use in attenuation of common cold symptoms, there is little information on the effects of acute overdose. A 17-year-old male ingested approximately 85 tablets or 4 g zinc gluconate (570 mg elemental zinc). He experienced severe nausea and vomiting within 30 minutes of the ingestion but had no further sequelae such as diarrhea, gastric erosions, esophageal burns, shock, neurologic dysfunction, symptoms of anemia, or hepatic inflammation. Serum zinc level was 4.97 mg/dL at approximately 5 hours postingestion.
In India, sodium antimony gluconate is the drug of choice for kala-azar. Due to increasing unresponsiveness to this drug in the current epidemic that began in the early 1970s, daily doses of 20 mg/kg/day for 30 days or more is recommended as opposed to the 10 mg/kg/day dose for 6-10 days used in the past. Of the 130-150 patients treated annually at our center with locally made sodium antimony gluconate, serious cardiotoxicity has occurred in less than 10%. During April 1995 at the University Hospital in Varanasi, we encountered life-threatening cardiotoxicity after 3-28 days of therapy in each of the eight patients being treated with a new lot of this drug made by a different manufacturer. Of the eight patients, six each developed congestive heart failure and/or prolongation of the corrected QT interval (QTc), and three died as a direct consequence of drug-induced toxicities. In three instances, the life-threatening complications occurred with a cumulative dose of less than 300 mg/kg. In patients with prolonged QTc, ventricular premature beats and ventricular tachycardia were recorded; in one patient, the ventricular tachycardia progressed to torsade de pointes, culminating in ventricular fibrillation and death. Since switching to different lots of this drug, we have not seen further clustering of dangerous cardiotoxicity. The antimony content of the implicated drug was comparable with that in lots from other manufacturers that did not show overt toxicity, but the osmolarity was approximately 300 mOsm/L higher. The simple technique of measuring of osmolarity may help identify inappropriately manufactured drug.
Extravasation of calcium gluconate is not an uncommon complication in neonatal units, which may result in skin and soft tissue inflammation, injury and even infection. We report an 11-day-old preterm infant who developed osteomyelitis at an infiltrated intravenous site through which calcium gluconate was infused. The patient was initially treated conservatively as a simple calcium-infiltrate. Clinical condition deteriorated until proper antibiotic treatment was given. We exclude other possible causes and assume that calcium-infiltrate had an important role in the pathogenesis. We conclude that osteomyelitis should be considered in a patient with calcium extravasation whose soft tissue inflammation does not improve as expected. Furthermore, using a diluted calcium solution and checking the insertion site frequently in order to identify extravasation earlier would prevent the complication.
The conversion of glucose and fructose into gluconic acid (GA) and sorbitol (SOR) was conducted in a batch reactor with free (CTAB-treated or not) or immobilized cells of Zymomonas mobilis. High yields (more than 90%) of gluconic acid and sorbitol were attained at initial substrate concentration of 600 g/L (glucose plus fructose at 1:1 ratio), using cells with glucose-fructose-oxidoreductase activity of 75 U/L. The concentration of the products varied hyperbolically with time according to the equations (GA) = t (GA)max /(W(GA) + t), (SOR) = t (SOR)max/(W(SOR) + t), V(GA) = [W(GA) (GA)max]/(W(GA) + t)2 and V(SOR) = [W(SOR) (SOR)max]/(W(SOR) + t)2. Taking the test carried out with free CTAB-treated cells as an example, the constant parameters were (GA)max = 541 g/L, (SOR)max = 552 g/L, WGA = 4.8 h, W(SOR) = 4.9 h, v(GA) = 112.7 g/L x h and v(SOR) = 112.7 g/L x h.
Sodium gluconate transforms the bone-seekers 99mTc-HEDP and 99mTc-pyrophosphate into the renal agent 99mTc-gluconate. In these in vitro processes, pyrophosphate is displaced faster than HEDP, while the HEDP reaction is accelerated by calcium ions. The in vivo distributions of these bone and kidney agents are altered by the prior local injection of calcium or iron(II). These transformation and translocation phenomena are explained in terms of the mechanistic behavior of Tc(IV) complexes.
The gluconate (gnt) operon of Bacillus subtilis has been cloned and sequenced. Analysis of the sequence (5482 base pairs) revealed four open reading frames, each of which was preceded by a Shine-Dalgarno sequence. These four frames were designated from the 5'-end as gntR, gntK, gntP, and gntZ. The gntR and gntK genes overlapped by 5 bases. The gntK and gntP gene products (consisting of 513 and 448 amino acids) were identified as gluconate kinase and permease, respectively, by means of insertional inactivation and deletion analysis of these genes subcloned in plasmid pC194. The functions of the gntR and gntZ gene products (243 and 468 amino acids) are presently unknown. S1 nuclease mapping and subcloning in a promoter probe vector (pPL603B) provided evidence that the gnt operon was transcribed as a polycistronic mRNA. Besides the gnt promoter about 40 base pairs upstream of the gntR gene, we detected two overlapping internal promoters between the gntP and gntZ genes. The gnt transcripts terminate about 45 base pairs downstream of the gntZ gene.
Zinc is an trace metal necessary for T cell differentiation and maturation. Forty-two patients, with Aids Related Complex or malignancy in remission and with severe and stable CD4 lymphoid cells cytopenia were submitted to zinc gluconate, 125 mg twice daily orally for three weeks. Reevaluation of T cell subsets one week after the end of zinc intake showed non significant modification of total lymphocyte counts nor of CD4 subsets. CD8 cells however were significantly increased in absolute number in those patients with initially low counts of the cells while they were significantly reduced in those patients with initially normal or high CD8 cells counts. Zinc gluconate in short courses appear to act as a regulator of CD8 lymphoid cells subsets.
The various morphological and functional changes produced by lithium gluconate treatment of Mouse thyroid and ultimobranchial cells show complex interactions, involving direct and indirect effects. In most of the cases these effects determine metabolism (thyroid cells) or differentiation (ultimobranchial cell) disturbances. In most of the cases analysed changes do not concern the whole gland and should not have important consequences on its general activity-so it is more likely that at low concentration the effects of lithium gluconate on the thyroid gland of manic depressive patients might be neglected at the level of the functional state of the whole gland.
In 10 dogs experimental cardiomyopathy was produced using high intravenous doses of adrenaline and theophylline. The possibility of scintigraphic detection of this non-ischaemic damage was tested by means of 99mTc-gluconate. In 5 dogs the scintigraphic examination was carried out 4 hrs following the production of the damage. In all 5 cases a marked positivity of the heart scan was observed. The finding was confirmed by the radioactivity of tissue samples from all sections of the heart. In 3 out of 5 dogs the histological examination of the myocardium (PAS and HBFP staining) was positive. In the remaining 5 dogs the scan was performed 24 hrs following the development of the damage. A positive scintigraphic finding was observed in 4 cases, the degree of accumulation being lower than at 4 hrs. The radioactivities of tissue samples were also significantly lower as compared with the 4-hr values. In contrast, the histological findings were markedly positive in all 5 dogs. It follows that 99mTc-gluconate is capable of detecting in addition to infarctions non-ischaemic damages to the myocardium, too. The normalization of the finding is very quick. This experimental finding appears to be of importance in clinical practice.