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  • 1975-1979  (55,079)
  • 1970-1974  (5)
  • 1977  (55,079)
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Year
  • 101
    ISSN: 1432-1041
    Keywords: 16α-gitoxin ; 16-acetyl-16α-gitoxin ; ouabain ; digitoxin ; albumin binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The binding of semi-synthetic (16α-gitoxin and its 16-acetate) and naturally occurring cardioactive glycosides (digitoxin, ouabain) to human serum albumin was studied using equilibrium dialysis, ultracentrifugation and gel filtration. 16α-gitoxin was 75% bound and its 16-acetate 95%. The percentage binding of digitoxin and ouabain was in good agreement with values reported in literature.
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  • 102
    ISSN: 1432-1041
    Keywords: Protein binding ; plasma proteins ; adult ; newborns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The binding of various drugs to plasma proteins from adult and cord plasma was determined by equilibrium dialysis. For almost all the drugs binding to cord plasma was lower than to plasma from adults. No evidence was found that the difference in binding was due to the different protein concentration in cord and adult plasma or to an influence of substances in ultrafiltrates of the plasmas.
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  • 103
    ISSN: 1432-1041
    Keywords: Protein binding ; cord plasma ; adult plasma ; fractionated plasma proteins ; bilirubin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The binding of certain drugs to isolated fractions of plasma proteins obtained from newborn and adult man has been studied by equilibrium dialysis. For thiopental, desipramine, nitrofurantoin, sulfamethoxydiazine, meticillin and salicylic acid no difference was found between binding to the albumin fraction from newborns and adults. However, for thiopental, desipramine and promethazine binding to the globulin fraction was smaller in the newborns than in adults. Addition of bilirubin to the albumin fraction decreased the binding of nitrofurantoin, sulfamethoxydiazine and meticillin. No difference in the binding of meticillin to the albumin or globulin fractions from newborns and adults was found. The binding decreased, however, if both fractions were combined. Four mechanisms to explain the difference in binding between newborns and adults are discussed: (1) Displacement of drugs by bilirubin, (2) different binding properties of cord and adult albumin, (3) different properties of the globulins and (4) interaction of albumin with globulins in the newborn.
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  • 104
    ISSN: 1432-1041
    Keywords: Beta-adrenoceptor blockade ; cardioselectivity ; practolol ; plasma levels ; cardiac and pulmonary effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a group of 6 healthy (but physically unfit) volunteers an investigation was made of whether there was a true plasma level effect relationship and absolute “cardioselectivity” with respect to beta-adrenoceptor blockade due to practolol. To this end three treatments were given orally, namely placebo, practolol 100 mg and practolol 400 mg. Cardiac beta-adrenoceptor blockade was assessed by measuring the inhibition of exercise heart rate and pulmonary beta-adrenoceptor blockade was assessed by measuring the reduction in exercise peak flow rate, up to 24 h after each dose. Plasma practolol levels were determined spectrophotometrically. From the results obtained there was no reason to doubt the existence of a valid relationship between cardiac beta-adrenoceptor blocking activity and the plasma concentration of practolol. It was also concluded that even in non-asthmatics, practolol does not possess absolute “cardioselectivity” since significant reductions in peak flow rate were discernible during vigorous exercise, particularly when the large dose had been given.
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  • 105
    ISSN: 1432-1041
    Keywords: Prescriptions ; drug exposure ; pharmacotherapy ; surveillance ; methodology ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Prescribed drugs dispensed to 13% (17 000) of the inhabitants in the county of Jämtland, Sweden, have been continuously recorded since 1970. Individual patients in the investigation are fully identifiable by their identity number as used in Sweden, so patients exposed to a particular drug or group of drugs can be reached subsequently, e. g. for studies of the incidence and nature of side effects. The following information is coded at the local pharmacies: prescribing physician, dispensing pharmacy, year and week of dispensation, name, amount and price of drug, dosage, type of prescription record. In a five year period the drop-out rate has decreased from 9% in 1970 to 4% in 1974. Every year at least one drug is prescribed for approximately 60% of the population. During the five year period 74% of the male and 80% of the female population purchased prescription drugs. The representative nature of the data is discussed, as well as their value in detection of irrational drug usage and ascertaining any particular patient's drug history.
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  • 106
    ISSN: 1432-1041
    Keywords: Clofibrate ; hyperlipoproteinaemia ; glucose intolerance ; serum insulin ; plasma fibrinogen ; blood glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of clofibrate therapy were studied in fifty year old, weight-stable, free-living men not on specific dietary treatment. The patients had been selected because of hyperlipidaemia and/or glucose intolerance found at a health screening survey. The study lasted for four months and was double-blind and cross-over in design. The results showed no effect of clofibrate treatment on glucose tolerance, as measured by an intravenous glucose tolerance test, neither in the entire group (t=0.90, 2p〉0.05, n=21) nor in a subgroup (t=−0.71, 2p〉0.05, n=10) with glucose intolerance on screening. Fasting blood glucose was significantly decreased (t=3.71, 2p〈0.01) in the subgroup (n=8) with fasting blood glucose greater than 100 mg/100 ml during the placebo period. There was, however, a significant (t=4.00, 2p〈0.001) reduction in fasting serum(S-)insulin concentration during clofibrate therapy. The reduction was correlated with relative body weight (r=0.59, 2p〈0.01). Elevated S-lipoproteins were decreased by clofibrate therapy, S-low density lipoprotein cholesterol concentrations by 20 per cent and S-very low density lipoprotein triglyceride concentrations by 52 per cent. Significant falls in plasma fibrinogen concentration (t=4.57, 2p〈0.001) and erythrocyte sedimentation rate (t=2.48, 2p〈0.025) also occured, which were not correlated to the other effects reported.
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  • 107
    ISSN: 1432-1041
    Keywords: Metronidazole ; serum concentration ; bioavailability ; food intake ; healthy subjects ; Crohn's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The possible influence of food intake on the bioavailability of metronidazole was examined in ten healthy volunteers by administration of a single dose of metronidazole on an empty stomach, and with a standardized breakfast. Food intake did not significantly alter the bioavailability of metronidazole. The interindividual variation in bioavailability appeared to be slight. In nine patients with Crohn's disease, the absorption of metronidazole appeared to be reduced and to be more variable than in healthy subjects. In both groups there was a clear relationship between the amount absorbed and dose/kg body weight. Thus, from the pharmacokinetic point of view, metronidazole can safely be given either with or between meals. The dose should be related to body weight.
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  • 108
    ISSN: 1432-1041
    Keywords: Benserazide ; decarboxylase inhibition ; alpha-methyldopa ; essential hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a single-blind study, the dopa-decarboxylase inhibitor benserazide (375 mg/day for 3 days and 750 mg/day for further 3 days) and a placebo were given orally in combination with individually effective doses of alpha-methyldopa (mean 1.5 g/day) to 3 hospitalized patients with essential hypertension. Alpha-methyldopa (α-MD) alone lowered blood pressure from 165/107 to 136/93 mm Hg (P〈0.05). Benserazide did not alter the hypotensive effect of α-MD, although the decarboxylation of α-MD was markedly reduced, as shown by the urinary excretion of alpha-methyldopamine (α-MDA). During administration of α-MD alone, the ratio α-MD/α-MDA in urine of the 3 patients was 8:1, 7:1 and 22:1, respectively. When benserazide 375 mg/day was added the ratio rose to 31:1, 31:1 and 35:1; the ratio was 37:1, 18:1 and 46:1 at the higher dose of inhibitor. In a double-blind crossover study the effect on blood pressure of 3 weeks of treatment with α-MD (mean 1.75 mg/day), benserazide (375 mg/day), placebo and their combinations were compared in 5 hypertensive subjects. Again, benserazide did not influence the antihypertensive action of α-MD. To study whether benserazide entered the CNS, a single oral dose of14C-benserazide of 125 mg was given to 2 patients who were to undergo diagnostic lumbar puncture. Two hours after intake of the labelled drug, when radioactivity in blood had reached a maximum, the concentration of radioactivity in spinal fluid was less than 1% of the plasma level. Thus, the antihypertensive action of α-MD was not influenced by oral doses of the decarboxylase inhibitor benserazide. The results suggest that benserazide in doses up to 750 mg/day does not affect central decarboxylation of α-MD and that this antihypertensive agent lowers blood pressure by a central action.
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  • 109
    ISSN: 1432-1041
    Keywords: Humoral immunity ; cell-mediated immunity ; D-penicillamine ; Wilson's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Humoral and cell-mediated immunity were studied in a group of patients with Wilson's disease not previously treated with D-penicillamine, and in a group of patients treated with the drug for more than two years. The previously untreated patients showed an exaggerated humoral immune response, i. e. increased levels of IgG and, IgM, higher titer of antibodies to Kunin's antigen, and depression of cell-mediated immunity, namely a decreased response to DNCB, decreased lymphocyte transformation after stimulation with Con A, PPD, Candida and streptokinase and a reduced response to streptokinase in the MIF test. After treatment the humoral response returned to normal, and in the case of IgA and antibodies to S. typhi O antigen, it even dropped below normal values. The cell-mediated immune response returned to normal with the exception of lymphocyte transformation by PHA and Candida albicans. In in vitro studies it was found that D-penicillamine had no influence on lymphocyte transformation when PHA and Con A were used as mitogens. With PPD as antigen, lymphocyte stimulation and migration inhibition were inhibited by concentrations of penicillamine ranging from 6 to 1000 µg/ml.
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  • 110
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1432-1041
    Keywords: Phenobarbital ; pharmacokinetics ; neonates ; infancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In 14 neonates 1–4 weeks old, 30 babies aged 1–12 months, and 7 infants of 1–5 years of age, the serum levels of phenobarbital were determined by a gas chromatographic micro-method after intravenous injection of phenobarbital 5–10 mg per kg body weight. It was possible to calculate the pharmacokinetic parameters using a two compartment open model. The distribution volumes within the individual age groups and the rate constants k12 and k21 showed no significant differences, but the elimination half-life was significantly longer in neonates (118.6±16.1 h) than in babies (62.9±5.2 h) or infants (68.5±3.2 h).
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  • 111
    ISSN: 1432-1041
    Keywords: Fluoride ; single- and multiple dose kinetics ; plasma concentration ; urinary excretion ; saliva/plasma concentration ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The doses of fluoride (F) recommended in the literature for caries prevention and for the treatment of osteoporosis vary. This partly reflects inadequate knowledge of F pharmacokinetics. In the present study various single and multiple oral doses of F were given to eight volunteers, who had a strictly controlled F intake in the diet. The resulting plasma and parotid saliva concentrations as well as urinary output of F were measured. The plasma data fitted a two-compartment open model with a β-slope half-life ranging between 2 and 9 h. Plasma clearance was 0.15±0.02 (SD) liter/kg/h. Data from the highest dose (10 mg) were fitted to both two- and three-compartment models, and there was no significant difference between them. Multiple doses of F 3.0 or 4.5 mg yielded steady state concentrations ranging from 54 to 145 ng/ml. About 50 per cent of the given dose was recovered in the urine, which is indicative of considerable accumulation in the body. The saliva F/plasma F concentration ratio was 0.64 with a coefficient of variation of 5%.
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  • 112
    ISSN: 1432-1041
    Keywords: Muzolimine ; pharmacodynamics ; pharmacokinetics ; furosemide ; saluresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a biometrically planned, double-blind study on 12 Oedema-free male patients the saluretic effect of muzolimine 30 mg was compared with furosemide 40 mg. The plasma level of muzolimine was determined and correlated with its pharmacodynamics. In terms of excretion during the 12-hour observation period muzolimine 30 mg had as great a cumulative effect as furosemide 40 mg. There was a significant difference in the time-response curve. During the first two hours furosemide 40 mg had more saluretic effect than muzolimine 30 mg. Between two and four hours there was no significant difference between the two substances. Between four and six hours, however, muzolimine was somewhat more effective than furosemide, although the difference did not reach the level of significance. After 6 h there was no longer any difference between the two compounds. The half-life of the fall in concentration of muzolimine in plasma was 3.7 up to 10 h after its administration. The time-response curve of the increased urine excretion correlated well with the time course of the concentration of muzolimine in plasma.
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  • 113
    ISSN: 1432-1041
    Keywords: Imipramine ; depression ; subjective effects ; EEG changes ; psychological performance changes ; plasma concentrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Ten patients with psychotic depression were assessed on a battery of clinical, EEG, psychological, and biochemical measures during treatment with imipramine (150 mg/day). Significant changes occurred in the scores on self-rated and observer-rated depression scales and on an observer-rated side effect scale. Significant changes also occurred in the EEG evoked response, but the effects on spontaneous activity were minimal. The psychological measures revealed an improvement in performance as treatment progressed. The clinical significance of the changes observed was assessed with reference to their correlations with the clinical rating scores and with the plasma concentrations of imipramine and desmethylimipramine, and the changes observed following the administration of imipramine to non-depressed normal subjects. Changes in evoked EEG activity seemed on balance to be direct central effects of imipramine, whereas changes in psychological performance appeared to be secondary to clinical change.
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  • 114
    ISSN: 1432-1041
    Keywords: Sulphamethizole ; tetracycline ; doxycycline ; rest ; exercise ; pharmacokinetics ; excretion ; absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The serum level and urinary excretion of sulphamethizole, tetracycline and doxycycline were studied in healthy volunteers subjected to intensive exercise and bed rest in a cross-over trial. Each group consisted of 7–8 subjects. The exercise or bed rest began 15 min before oral administration of the drug and was continued for the following 4 hours. During exercise serum drug concentration and the area under the serum concentration-time curve for each agent was significantly higher (p〈0.05) than the corresponding values at rest. Exercise greatly suppressed the renal excretion of tetracycline and doxycycline, but the decrease alone appeared insufficient to account for the pronounced increase in serum drug concentration. Total drug excretion in urine was unchanged. Thus, it seemed most unlikely that overall absorption from the gastrointestinal tract had been altered by exercise. However, the rate of absorption appeared to be more rapid in the exercise than in the rest period. Marked haemoconcentration was not produced by the exercise. In addition to changes in absorption and elimination rates, alteration in the volume of distribution might contribute to the higher serum drug concentration during exercise. Therefore, the level of physical activity should be considered in the interpretation of pharmacokinetic data both in clinical practice and in pharmacokinetic studies.
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  • 115
    ISSN: 1432-1041
    Keywords: Aminopyrine metabolism ; 14CO2-breath test ; aminopyrine demethylation ; dose dependent metabolism ; physical fitness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Although the aminopyrine breath test has received much attention, the question has not yet been settled whether pharmacological or tracer doses of the drug should be used. Nine volunteers were given14C-aminopyrine 9 mg/kg or a tracer amount, in a randomized sequence and according to a crossover design. The specific activity of14CO2 in breath was significantly different only during the first hour. Up to the 8th hour the disappearance of14CO2 from breath was smaller after the pharmacological (28.5±SD 5.4%/h) than after the tracer dose (36.2±10.6%/h; p〈0.05). The overall disappearance of14C-atoms from the subjects was significantly slower after the higher dose. In view of the smaller radiation exposure and the decreased risk of agranulocytosis, the use of a tracer dose appears preferable.
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  • 116
    ISSN: 1432-1041
    Keywords: Aldosterone antagonists ; aldosterone infusion ; evaluation in man ; spironolactone ; potassium canrenoate ; spironolactone metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A method of assessing the qualitative and quantitative activity of competitive aldosterone antagonists in healthy man is described. It requires intravenous infusion of aldosterone (0.5 mg/6 h), iv and oral water loading for six hours and fractionated collection of urine over eight hours. Aldosterone antagonists were administered orally 1.5 h before the start of the infusion (spironolactone 50, 200 or 800 mg) or added to the infused solution (potassium canrenoate 300, 600 or 1000–1200 mg). The effect was assessed by changes in urinary sodium and potassium excretion and in urinary Na+/K+ ratio. The plasma levels and urinary excretion of canrenone, canrenoate and canrenoate ester glucuronide, respectively, were determined after administration of spironolactone and potassium canrenoate. Between 4–8 h (spironolactone) or 2–8 h (potassium canrenoate) after commencement of the infusion there was linear, dose-dependent reversal of the mineralocorticoid-induced sodium retention and/or decrease in the Na+/K+ ratio. The plasma levels and urinary excretion of the metabolites measured were also dose-dependent. The method appears suitable for comparison of the potency of aldosterone antagonists and for defining the time course of drug action within the observation period employed.
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  • 117
    ISSN: 1432-1041
    Keywords: Cefoxitin ; lidocaine ; intramuscular ; bioavailability ; pain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The use of lidocaine HCl solution at concentrations of 0.5 and 1.0% to reconstitute sodium cefoxitin relieves the pain associated with intramuscular injections of the antibiotic. Cefoxitin absorption by the intramuscular route is initially rapid and is virtually complete. Peak serum concentrations, corresponding to about one-half those of a comparable intravenous infusion, are achieved in 30 min. Continuing absorption tends to maintain higher serum concentrations for longer times. Renal clearance and serum half-life of cefoxitin do not appear to be affected by lidocaine at its effective anaesthetic concentrations.
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  • 118
    ISSN: 1432-1041
    Keywords: Interactions ; glafenine ; phenprocoumon ; hypoprothrombinaemia ; clotting factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The interaction between phenprocoumon (Marcumar®) and glafenine (Glifanan®) was investigated in a double blind study of twenty patients receiving long term treatment with phenprocoumon. Thrombotesttime (TT) values had been stable for more than three months before the study. Patients taking glafenine showed a significant increase in TT during the second and third week of the trial (P〈0.05) compared with the placebo group. The increase in TT was not significant in the fourth week. The average concentrations of phenprocoumon were similar in both groups, which suggests that displacement of the drug from binding was not important. Concentrations of clotting factors II, VII and X showed a decrease in all patients at the time of the maximum TT values. A possible explanation for this interaction is discussed, but the mechanism remains uncertain.
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  • 119
    ISSN: 1432-1041
    Keywords: Clonidine ; Yohimbine ; sleep ; REM sleep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Clonidine (300 µg orally) increased in man the total duration of sleep and strikingly reduced the duration of REM sleep. Yohimbine (10 mg per os) did not alter the sleep patterns in man but antagonized the effects of clonidine. These results provide evidence that an α sympathomimetic mechanism could suppress REM sleep and increased the total duration of sleep.
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  • 120
    ISSN: 1432-1041
    Keywords: β-adrenergic blocker ; acebutolol ; central actions ; EEG ; automatic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of acute intravenous injection of acebutolol 25 mg on the EEG were investigated in 5 normal subjects. On-line EEG analysis was carried out by a special purpose mini-computer using normalised slope descriptors (Hjorth parameters). No significant changes were found apart from those due to drowsiness in 2 subjects, although minute to minute ECG frequency was significantly lowered (p=0.031). The EEG, which is considered to be a sensitive tool, failed to show any conclusive evidence of any central action of the drug. The effects of beta-adrenergic blockers on the CNS are not yet fully understood.
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  • 121
    ISSN: 1432-1041
    Keywords: Emetine ; phagocytosis ; alveolar macrophages ; intracellular killing ; polymorphonuclear granulocytes ; libexine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The ability of human polymorphonuclear granulocytes and alveolar macrophages from rats to ingestSaccharomyces cerevisiae was tested in vitro in the presence of various concentrations of emetine and libexine. Emetine 4.0 and 40.0 µg/ml caused an increase in the phagocytic index of polymorphonuclear granulocytes and alveolar macrophages. After oral administration of emetine the phagocytosis-enhancing effect was still apparent. Intracellular killing was not influenced by emetine or libexine.
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  • 122
    ISSN: 1432-1041
    Keywords: Etidocaine ; epidural ; total blood clearance ; metabolism ; plasma protein binding ; placental transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Following epidural administration of etidocaine hydrochloride to non-pregnant and pregnant patients, a similar rate of absorption was observed and there was no significant difference in total systemic blood clearance (Clsb) of etidocaine in the two groups. There were no major differences in the urinary excretion of etidocaine and metabolites in 48 h urine in both groups. The ability of pregnant women to form the N-glucuronide of the metabolite ABX (2-amino-2′-butyroxylidide) was similar to that of non-pregnant individuals. In vitro experiments showed that the blood/plasma concentration ratio (λ) of etidocaine was significantly higher in pregnant females than in males, presumably due to the lower haematocrit in females. The fraction unbound in plasma (fp) of etidocaine was low in control subjects (mean 0.057) and was not significantly different in pregnant women of 35 to 37 weeks gestation. A marked increase in fp was observed in pregnant women during delivery (mean 0.264). This finding has potentially serious clinical implications because it is the unbound drug in blood which is pharmacologically important. Placental transfer of etidocaine was rapid and the cord/maternal venous blood concentration ratio at delivery (CMb) was, with one exception, always less than unity (mean 0.342). Following epidural administration of etidocaine to pregnant women in labour, measurable concentrations of mono-dealkylated metabolites of etidocaine, PABX (2-N-propylamino-2′-butyroxylidide) and EABX (2-N-ethylamino-2′-butyroxylidide) were detectable in maternal blood within 5 min and cord blood within 30 min. The CMb for PABX and EABX was 0.401 and 0.658 respectively.
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  • 123
    ISSN: 1432-1041
    Keywords: Benzodiazepine ; temazepam ; pharmacokinetics ; bioavailability ; hard and soft gelatine capsules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Plasma levels of temazepam were determined in healthy subjects after single oral administration of soft and hard gelatin capsules, and after 7 consecutive night-time doses in soft capsules. Absorption from soft gelatin capsules was significantly faster and produced earlier and higher peak plasma levels. The two pharmaceutical forms did not show any significant difference in relative availability. The apparent half-life of temazepam after night-time administration was significantly shorter than after morning administration, but no change in half-life was observed between the first and seventh night-time doses.
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  • 124
    ISSN: 1432-1041
    Keywords: Methyclothiazide ; blood pressure ; plasma volume ; renin ; aldosterone ; electrolytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Home blood pressure measurements were used to assess the effect of methyclothiazide in young essential hypertensive and normotensive males. Although plasma volume was reduced by approximately 10 percent, blood pressure was not reduced in either group. The lack of effect on blood pressure was probably not attributable to dosage employed, as doubling the dose (5 to 10 mg) in the normal subjects (who were equilibrated on constant diet) did not significantly increase changes in plasma volume, plasma renin activity, aldosterone excretion, urine sodium or blood pressure. The higher dose did result in greater changes in plasma potassium and uric acid. Homeostatic mechanisms which limit the volume mediated and other antihypertensive effects of methyclothiazide apparently achieved complete compensation in these young males. This suggests that thiazide diuretics may not be the drug of first choice in the treatment of hypertension in young adults. Further studies with other diuretics are clearly necessary before the significance of these findings can be fully assessed.
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  • 125
    ISSN: 1432-1041
    Keywords: Circadian urinary pH ; chronic antacid ; statistical analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In normal human volunteers, when urinary pH was plotted versus time, the circadian sine-wave type curve was not altered by chronic administration of a commercially available suspension containing a mixture of magnesium and aluminum hydroxides, although the antacid perturbed the entire curve in a more alkaline direction. A single dose of the antacid had little effect on urinary pH. There was a highly significant linear relationship between the change in hydrogen ion concentration during chronic antacid treatment and the initial control urinary hydrogen ion concentration, but there was no significant correlation between change in urinary pH and initial control urinary pH as has been previously reported. The above results were based on the evaluation of the hydrogen ion concentrations of 1562 separate urine samples collected from 24 normal subjects in a three treatment crossover study. It is recommended that: (1) research studies involving drug-drug interactions with antacids be designed to consider the effect of the antacid on the circadian rhythm of urinary pH, and (2) pH values not be averaged as commonly reported in the literature, but rather the pH values be converted to hydrogen ion concentrations before statistical analysis.
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  • 126
    ISSN: 1432-1041
    Keywords: Digoxin ; hypothyroid ; hyperthyroid ; thyroid dysfunction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The response to a single oral dose of 0.5 mg digoxin has been studied in eight patients, of whom four were hyperthyroid and four were hypothyroid, both before and after treatment for their thyroid dysfunction. The post-dose plasma digoxin levels were significantly lower in the hyperthyroid patients when they were thyrotoxic than when they became euthyroid. In only one hypothyroid patient was the post-dose plasma digoxin level significantly higher before treatment than it was after and in the others the digoxin values reached were either the same as, or lower than, before treatment. There was a significant correlation between the creatinine clearance and the urinary concentrations of digoxin and these both altered with change in thyroid status. Total urinary digoxin excretion did not change. Pharmacokinetic analysis suggested that digoxin was distributed in a way compatible with a two-compartment model and that the volume of the central compartment was high in thyrotoxic patients and low in hypothyroid patients. In both cases it reverted to a median value after treatment. It is recommended that plasma digoxin levels should be monitored in all patients with thyroid dysfunction who require therapeutic digoxin.
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  • 127
    ISSN: 1432-1041
    Keywords: 3H-16-acetyl-16α-gitoxin ; 3H-pentaacetyl-16α-gitoxin ; absorption ; half-life ; excretion in urine and bile ; metabolism ; cannulated bile duct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 3H-16-acetyl-16α-gitoxin or3H-pentacetyl-16α-gitoxin were injected iv or administered po to 15 volunteers and 3 patients. The elimination half-life and excretion in urine within 4 days were estimated as a percentage of the administered radioactivity, and metabolic studies on the fate of the administered glycosides were performed. In volunteers the following results were obtained:3H-16-acetyl-16α-gitoxin 1 mg iv.: 50±11 h, 28.3±4.1%;3H-16-acetyl-16α-gitoxin 1mg po: 48±8 h, 25.4±2.8%;3H-penta-acetyl-16α-gitoxin 2 mg po: 51±12 h, 20.7±3.2%, respectively. In 3 patients with a cannulated bile duct 9.9% (mean) of the administered3H-16-acetyl-16α-gitoxin was excreted. By comparison of the radioactivity excreted in urine following the 2 routes of 16-acetate administration, the percentage absorption was calculated to be 88.5%. In serum and urine 16-acetyl-16α-gitoxin and 16α-gitoxin were found as possible metabolites of both glycosides, in the ratio of 75–85: 15–25, and both metabolites were also found in bile. Within 16 h after penta-acetate administration, two additional metabolites (bis-acetylderivatives of 16α-gitoxin) were detected in serum and urine within 16 h after administration of pentaacetate.
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  • 128
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    Archives of microbiology 112 (1977), S. 111-114 
    ISSN: 1432-072X
    Keywords: Podospora anserina ; Phenol oxidases ; Laccases II, III ; m-Phenols ; Enzyme kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For the low molecular weight laccases II and III of Podospora anserina the kinetic parameters Michaelis constant (K M) and maximum reaction velocity (V) were determined polarographically under pH optimum conditions for representative substrates of different substitution patterns. Laccase II showed two peaks in its pH optimum curve, each with a different substrate specificity, indicating structural differences to laccase III which exhibits only one broad peak. Under optimum conditions the affinities of various substrates are determined by their substitution patterns: high affinity for simple o-and p-diphenols, low affinity for m-phenols. The maximal velocity remains largely uninfluenced. This study of the effect of substitution on substrate utilization leads to the assumption that there is no specific reactive site for m-phenols in either laccase. Oxidation of m-phenols, however, takes only place at high pH values.
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  • 129
    ISSN: 1432-072X
    Keywords: Nitrosomonas spec ; Ammonia oxidizing bacterium ; Polyhedral inclusion bodies ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyhedral inclusion bodies were observed in cells of a Nitrosomonas species. They were present in growing cells as well as in resting cells. In thin sections their size was about 130 nm in growing cells and about 185 nm in diameter in resting cells. The bodies were commonly located in the nucleoplasm. They appeared to be bounded by a nonunit membrane and had a granular substructure. In thin sections about 70% of the exponentially grown cells and about 20% of the resting cells of the investigated strain showed 1–7 respectively 1–3 inclusion bodies.
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  • 130
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    Archives of microbiology 112 (1977), S. 73-79 
    ISSN: 1432-072X
    Keywords: Induction ; Bioluminescence ; Luciferase ; Luminous bacteria ; Photobacterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The synthesis of the luminous system of the marine luminous bacterium Photobacterium fischeri is subject to a complex, self-regulated control system called autoinduction. The bacteria produce an autoinducer which accumulates in the medium at a constant rate (as a function of cell growth). When autoinducer reaches a critical concentration it stimulates, at the level of transcription, the synthesis of the luminous system. Autoinduction is thus viewed as an environmental sensing mechanism, which curtails the synthesis of the luminous system under dilute conditions. For several isolates of P. fischeri it was found that variations in luminescence intensity could be accounted for by correlated variations in autoinducer production.
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  • 131
    ISSN: 1432-072X
    Keywords: Phycobilisomes ; Isolation methods ; Phycobiliproteins ; Accessory photosynthetic pigments ; Rhodella violacea ; Rhodophyceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Disc-shaped phycobilisomes were purified from Triton X100 treated cell homogenates of the unicellular marine red alga, Rhodella violacea. Their absorption spectrum had principal maxima at 544 and 568 nm (B-phycoerythrin), 624 nm (C-phycocyanin) and a distinct shoulder at 652 nm (allophycocyanin). Intermolecular energy transfer within the phycobilisomes was clearly demonstrated by fluorescence data. Excited at 546 nm intact phycobilisomes showed a main fluorescence emission maximum at 665 nm, a minor one at 577 nm and a shoulder at 730 nm. Dissociated phycobilisomes revealed a composition of 58% B-phycoerythrin, 25% C-phycocyanin and 17% allophycocyanin under the cultural conditions used. Analytical methods resolved no other components than phycobiliproteins. In addition to the defined C-phycocyanin and two isoproteins of B-phycoerythrin a stable heterogeneous aggregate of B-phycoerythrin/C-phycocyanin was separated in considerable amounts. In the electron microscope negatively stained phycobilisomes appeared as elliptical aggregates having dimensions slightly above the values found in ultrathin sections and a detailed subunit structure. All observations and data suggest a new rhodophytan phycobilisome type in Rhodella violacea.
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  • 132
    ISSN: 1432-072X
    Keywords: Hydrogen bacteria ; Hydrogenase ; Localization ; Membrane bound enzymes ; NAD reduction ; Stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alcaligenes eutrophus strains H 16, B 19, G 27 and N9A contained two different hydrogenases. One enzyme catalyzed the reduction of NAD by hydrogen and was strictly localized in the soluble cell fraction, while the second enzyme was found to be particulate and unable to react with NAD. All other tested strains, Alcaligenes paradoxus SA 29, Pseudomonas facilis, P. palleronii RH 2, Pseudomonas sp. strain GA 3, Paracoccus denitrificans, Aquaspirillum autotrophicum SA 32, and Corynebacterium autotrophicum 14g and 7C contained only a single enzyme exclusively bound to membranes. This was established using fractional centrifugation, indicator enzyme systems, gentle methods of cell disintegration and discontinuous sucrose density gradient centrifugation. In cell-free extracts obtained by rough disruption (sonication) of cells, hydrogenase was associated to particles of different size and sedimentation velocity. A partial solubilization of hydrogenase caused by sonication was observed with P. facilis. Without exception, the particulate hydrogenases were found (1) to be unable to reduce pyridine nucleotides, and (2) to reduce methylene blue at an extremely high activity. The eminent reaction rate of 34 μmoles H2 oxidized per min and mg protein has been determined in particle suspensions of Pseudomonas sp. strain GA 3. All hydrogenases were stable during storage under hydrogen atmosphere, except the soluble enzyme from A. eutrophus H 16 which was shown to be more stable under aerobic conditions.
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  • 133
    ISSN: 1432-072X
    Keywords: Propionibacterium ; Fumarate reduction ; Cytochromes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fumarase-free electron particles from Propionibacterium freudenreichii and P. pentosaceum were prepared by discontinuous sucrose gradient centrifugation, and the influence of 2-n-heptyl-4-hydroxy-quinoline-N-oxide (HQNO) and ultraviolet irradiation on the reduction of menaquinone and cytochrome b with l-lactate or glycerol-3-phosphate and the reoxidation by fumarate was studied. In the presence of HQNO the steady state reduction level of menaquinone during fumarate reduction was increased whereas the steady state reduction level of cytochrome b was decreased as compared with the reduction levels measured in the absence of HQNO. The steady state reduction level of menaquinone during electron transport to fumarate was not influenced by ultraviolet irradiation and the steady state reduction level of cytochrome b was decreased at increasing irradiation times. The data indicate that cytochrome b is involved in the electron transport to fumarate.
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  • 134
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    Archives of microbiology 112 (1977), S. 287-289 
    ISSN: 1432-072X
    Keywords: Allohydroxy-d-proline ; d-Amino acid ; Dehydrogenase ; Pseudomonas aeruginosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth of Pseudomonas aeruginosa PA01 on isomers of hydroxyproline induced the synthesis of an allohydroxy-d-proline dehydrogenase. The enzyme resembled the d-alanine dehydrogenase of this organism in its association with the particulate fraction and its linkage to oxygen through a cytochrome-containing respiratory chain, but differed from this and other bacterial d-amino acid dehydrogenases in its high substrate specificity and low K m .
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  • 135
    ISSN: 1432-072X
    Keywords: Herpetosiphon ; Gliding bacteria ; Carotenoid glucosides ; Menaquinones ; Chemosystematic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gliding bacterium Herpetosiphon giganteus Hp a2 was shown to contain γ-carotene, one monoglucosyloxy and two new diglucosyloxy carotenoids with a x-O-acyl-diglucosyloxy carotenoid as main component. Flexirubin-like pigments could not be detected in this organism. As in the Myxobacterales and Cytophagales (Kleinig et al., 1974) menaquinones (MK-6 and MK-7) were found to be the only isoprenoid quinones present in Herpetosiphon. The chemosystematic implications of these findings are briefly discussed.
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  • 136
    ISSN: 1432-072X
    Keywords: Alkaline phosphatase ; Adaptation ; Derepression ; Repression ; Phosphite ; Hypophosphite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When Escherichia coli cells were grown in media containing either phosphite or hypophosphite as the sole source of phosphorus, they responded to this situation primarily in the same way as phosphatelimited cultures: The activity of alkaline phosphatase increased drastically, which under natural conditions would enable the cells to compklensatae for the shortage increased drastically, which under natural conditions would enable the cells to compensate for the shortage of phosphate. Subsequent transfers, however, resulted in a quite different response: While the phosphatase activity of phosphate-limited cells stays at a high derepressed level, its increase was followed by a gradual decline in organisms grown on phosphite or hypophosphite. After eight to ten transfers on these P-compounds, phosphatase activity was back to its initial, repressed, low level, indicating that the cells were fully adapted to these substrates. Adaptation to either PO 3 3- or PO 2 3- was completely abolished if the cells were again grown with PO 4 3- as P-source, whereafter the entire process of adaptation had to be repeated. The observed adaptation pattern, reflected by the alterations of phosphatase activity, was qualitatively equal with PO 3 3- and PO 2 3- , but quantitatively different, because the response to hypophosphite gave much higher values than the increase obtained with phosphite. Phosphite-adapted cells are not simultaneously adapted to hypophosphite, but their response to the latter was less intense than observed after direct transfers from PO 4 3- to PO 2 3- . Adaptation to hypophosphite, however, led simultaneously to phosphite adaptation, so that these cells can utilize both P-compounds as a substitute for phosphate.
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  • 137
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    Archives of microbiology 112 (1977), S. 255-261 
    ISSN: 1432-072X
    Keywords: Allomyces arbuscula ; Gametangia differentiation ; Gametangial polysomes ; Gel electrophoresis ; RNA synthesis ; rRNA degradation ; Sucrose gradient analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polysomes were isolated both from growing gametophytes of Allomyces arbuscula and from gametangia prepared from mycelia at different periods during gametogenesis. Analysis of polysomes by sucrose gradients showed that ribosomes present in the gametangia monosome pool were shifted into polysomes. This shift was found to be correlated with gametangia differentiation. The ribosome distribution remained virtually unchanged during the early stage of gamete formation. In mature gametes and swarming zygotes a low level of polysomes was detected. Labeling of rRNA by 32PO4 demonstrated a de novo synthesis of monosomes throughout the period of gametangia differentiation. No incorporation of 32PO4 was found to be present in ribosomes prepared from gametangia after onset of gamete formation. On the basis of these labeling experiments it is concluded that radioactivity in polysomes extracted from mature gametes and swarming zygotes can be attributed in part to conserved mRNA. Synchronous formation of gametangia was induced by transferring the vegetative mycelia from growth medium into a low salt buffer. Under these conditions the incorporation of either 32PO4 or 3H-uridine into RNA, particularly into rRNA, was found to be markedly decreased. This obviously indicates a shutdown of RNA synthesis. rRNA from induced mycelia examined by polyacrylamide gel electrophoresis was found to be severely degraded. In contrast to this, rRNA isolated from ribosomes of developing gametangia and from gametes exhibited no degradation products. It is suggested that endonucleases cause rRNA hydrolysis in the hyphal cytoplasm during gametangia differentiation. Ribosomes compartmentalized in gametangia seem to be inaccessible to nucleases during the later process of gametogenesis.
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  • 138
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    Archives of microbiology 112 (1977), S. 283-285 
    ISSN: 1432-072X
    Keywords: Wine yeasts ; Sulfur metabolism ; Regulation ; Sulfate uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Five different strains of wine yeasts were investigated with respect to active uptake of [35S] sulfate and its regulation by methionine. Considerable differences exist between “low” and “high” sulfite-producing strains in the initial velocity of sulfate uptake. Further differences were established in repression of sulfate permease by l-methionine, most evident in a total lack of repression in one of the “high” sulfite producers. These findings explain in part variable sulfite and sulfide formation.
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  • 139
    ISSN: 1432-072X
    Keywords: Phycomyces ; Cell wall carbohydrates ; GDP-fucose synthesis ; Spores ; Sporangiophores ; Hyphae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The carbohydrate composition of the cell walls from spores, mycelium and sporangiophores of Phycomyces blakesleeanus was analyzed. Spore wall polysaccharides contained over 50% glucose, about 20% uronic acids, 10% mannose and 10% amino-sugars. During the growth of the hyphae amino-sugars became the main carbohydrate (45%); uronic acids contributed some 25%, glucose and fucose 10% and galactose nearly 6%. Sporangiophores contained almost 90% aminosugars and some 6% uronic acids. Traces of rhamnose were found in all wall preparations. A similar picture emerged from studies on the incorporation of [U-14C]-glucose into wall materials. Furthermore we looked for a GDP-fucose synthesizing system and found an increasing activity during early germination. This rise in activity was inhibited by cycloheximide but not by 5-fluorouracil.
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  • 140
    ISSN: 1432-072X
    Keywords: Malate oxidase ; Carotenoids ; Photosensitivity ; Respiratory chain ; Light ; Sarcina lutea ; Micrococcus luteus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of white light on the malate oxidase of Sarcina lutea (Micrococcus luteus) membranes has been examined using a carotenoid-containing and a carotenoidless mutant. At least three photosensitive sites have been detected. Two of these are associated with the malate dehydrogenase complex (malate-menaquinone reductase) and are unaffected by membrane carotenoid. A third site which has been detected beyond the dehydrogenase complex, is protected by carotenoid since it can only be demonstrated in carotenoidless systems. A repair mechanism has been found for one of the two sites in the dehydrogenase complex.
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  • 141
    ISSN: 1432-072X
    Keywords: Transportsystem ; Thiamin ; Bacillus cereus ; Oscillationen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Bei dem untersuchten Transportsystem für Thiamin bei Bacillus cereus wechseln rhythmisch 1–2 h andauernde Aufnahme-und Abgabephasen miteinander ab. Diese großen Phasen sind in kleinere von durchschnittlich 45 s Dauer unterteilt. Die Geschwindigkeit der Thiaminaufnahme wird von pH-Wert, Temperatur, Alter der Zellen, Energie-und Nährstoffversorgung sowie Thiaminkonzentration des Mediums beeinflußt. Sie folgt der Michaelis-Menten-Kinetik: K m =1,98x10-8 M; V max=1,19x10-6 mol/g TGxmin. Gefördert wird die Aufnahmerate durch K+, Ca2+ und Mg2+, gehemmt wird sie durch Pyrithiamin, EDTA, H+-Ionen, Wasserstoffacceptoren und-donatoren; OH--Ionen bewirken eine Umkehr der Transportrichtung. Als erklärende Theorie wird eine Kopplung der Thiaminpermeation mit Protonenverschiebungen in der Membran diskutiert.
    Notes: Abstract The thiamine transport system in Bacillus cereus exhibits rhythmical changes of resorption-and excretion-phases lasting 1–2 h. These main phases are subdivided in shorter ones with an average duration of 45 s. The velocity of the thiamine uptake is influenced by pH, temperature, age of cells, energy and substrate supply and thiamine concentration of the medium. The Michaelis-Menten-Kinetic can be used to describe the uptake: K m =1.98x10-8 M; V max=1.19x10-6 mol/g dry weightxmin. The rate is enhanced by K+, Ca2+ and Mg2+, and inhibited by Pyrithiamin, EDTA, H+-ions, proton donors and proton acceptors; OH--ions cause a change in the direction of transport. A theoretical explanation can be given by assuming a coupling of the thiamine permeation with proton movements in the membrane.
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  • 142
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    Archives of microbiology 113 (1977), S. 61-64 
    ISSN: 1432-072X
    Keywords: Cellulase ; Metabolism ; Sophorose ; Trichoderma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cellulase inducer sophorose was rapidly catabolized to CO2 and H2O by Trichoderma: only small amounts were used to induce the synthesis of cellulase. 3H-sophorose uptake began after a lag of 1 h and its half-life in the medium was less than 5 h. Cellulase activity in the medium did not increase till 6 h after the addition of sophorose and reached a half maximum value at 14 h. The presence of free sophorose in the medium was required for continuous cellulase production. Several small sophorose addition induced much more cellulase than an equivalent single dose. These results are attributed to two pathways of sophorose utilization, a catabolic pathway that has a high capacity but low affinity for sophorose and an inductive pathway having a lower capacity but higher affinity for sophorose.
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  • 143
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    Archives of microbiology 113 (1977), S. 79-82 
    ISSN: 1432-072X
    Keywords: Coprinus ; Polysaccharide ; Glucan ; Cell wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An alkali-soluble polysaccharide was isolated from the purified mycelial walls of Coprinus lagopus. The hydrolysis products, optical rotation, and infrared spectrum indicate a β-glucan. Hydrolysis of the glucan after permethylation gave only 2,3,4,6-tetra-, 2,4,6-tri-, and 2,4-di-O-methyl-d-glucose. These methylated sugars and their relative quantities reveal that the glucan is a polysaccharide containing β-1,3-linked glucose units with about 14% of the sugars having 1,6-linked branch points. Partial hydrolysis of the product derived from Smith degradation of the glucan released laminaribiose and gentiobiose suggesting that the branches are generally longer than a single glucose unit.
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  • 144
    ISSN: 1432-072X
    Keywords: Desulfotomaculum acetoxidans ; Emendation of Desulfotomaculum ; Species description ; Anaerobic acetate oxidation ; Sulfate reduction ; Electron donors ; b-type cytochrome ; Sulfite reductase P582
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new strictly anaerobic, polarly flagellated, sporing, acetate-oxidizing, sulfate-reducing bacterium was isolated from anaerobic fresh or sea water mud samples. The oxidation of acetate to CO2 is stoichiometrically linked to the formation of H2S from sulfate. Ethanol, butanol and butyrate are also used. Hydrogen, lactate or pyruvate are not used as electron donors; organic substances are not fermented. A cytochrome of the b-type and a supposed sulfite reductase, P582, were detected spectrophotometrically. An emended description of the genus Desulfotomaculum is proposed which includes the new bacterium as the species Desulfotomaculum acetoxidans.
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  • 145
    ISSN: 1432-072X
    Keywords: Marine luminous bacteria ; Symbiosis ; Vibrio fischeri ; Cleidopus gloriamaris ; Taxonomy ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Luminous bacteria isolated from the light organs of the Australian Pinecone fish Cleidopus gloriamaris have been studied. The isolates were from fish from four different geographical estuarine systems on the east coast of Australia. All isolates were found to be strains of Vibrio fischeri, a species not hitherto demonstrated conclusively as forming a symbiotic association. Some ecological considerations are discussed.
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  • 146
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    Archives of microbiology 112 (1977), S. 179-185 
    ISSN: 1432-072X
    Keywords: Movement ; Phototaxis ; Carbon dioxide tension ; pH ; Circadian rhythm ; Chlamydomonas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. The effects of carbon dioxide, oxygen and pH on the inversion intensity of phototaxis of Chlamydomonas reinhardtii have been investigated. 2. With decreasing CO2 tension the inversion intensity is decreased. 3. The gassing with CO2 can be substituted by hydrogencarbonate only to a small extent (20%). On the other hand, the effect of decreasing CO2 tension can be prevented also only in part by adjusting the pH to about 6.5–7.0. Thus the effect of CO2 on the inversion intensity of phototaxis is obviously a compostite of a true CO2 effect and an effect of the concomitant pH change. 4. Oxygen has only a slight effect. In presence of oxygen (air) the phototactic reaction values are somewhat lower than in its absence. 5. Under certain conditions circadian rhythms seem to be initiated by changing oxygen as well as CO2 tensions. 6. Based on these results some contradictory results of older investigations are discussed.
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  • 147
    ISSN: 1432-072X
    Keywords: cAMP ; Regulation ; Chlorophyll synthesis ; Chlorella fusca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intracellular concentration of cAMP in the green alga Chlorella fusca was in the range of 2 · 10-9 to 10-8 moles/g dry weight and was strongly dependent on the growth conditions. The cAMP level was high with high light intensity, low nitrate or glucose concentration. Intracellular cAMP increased only by factor of 2 when high amounts (up to 10-3 M) of cAMP were added to the medium. Most of the given cAMP was converted to 5′-AMP. Addition of cAMP had little effect on the chlorophyll content of the cells, only at 10-6 M some enhancement in photoautotrophic cultures was observed. On the other hand high amounts of cAMP in the medium increased the growth rate. DBcAMP* showed a positive effect on chlorophyll synthesis and growth rate at much lower concentrations compared to cAMP. Stimulation effects of exogenous cAMP on the synthesis of chlorophyll were also observed in mixotrophic cultures with a high glucose/nitrate ratio, conditions where chlorophyll synthesis is repressed. Similar to autotrophic conditions DBcAMP was more effective than cAMP. These data indicate that cAMP may act in a system controlling the chlorophyll content of the cells in response to nutrients or light.
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  • 148
    ISSN: 1432-072X
    Keywords: Carnitine metabolism ; Carnitine derivatives ; Trimethylammonium-compounds ; Trimethylamine ; Acinetobacter calcoaceticus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Verwertung von Carnitin und Carnitinderivaten (O-Acylcarnitine, Carnitincarboxyl-derivate) und strukturverwandten Trimethylammoniumverbindungen (Betaine und Stickstoffbasen) durch Acinetobacter calcoaceticus wurde anhand des Wachstums und des quantitativen Nachweises der Metabolite untersucht. Der Stamm wuchs auf l-Carnitin, l-O-Acylcarnitinen und γ-Butyrobetain als jeweils einziger C-Quelle. Der Verbrauch dieser Verbindungen und das Wachstum korrelierten mit der Spaltung der C-N-Bindung und mit dem gebildeten Trimethylamin. d-Carnitin wurde metabolisiert, wenn als zusätzliche C-Quelle l-Carnitin im Nährmedium vorhanden war, oder wenn die Bakterien mit l-oder dl-Carnitin vorinkubiert worden waren. Mit d-Carnitin als einziger C-Quelle wuchsen die Bakterien jedoch nicht. Die Bakterien oxidierten Cholin zu Glycinbetain in Gegenwart einer zusätzlichen C-Quelle, Glycinbetain selbst wurde nicht assimiliert. In Hinsicht auf den Abbau quaternärer Stickstoffverbindungen besitzt Acinetobacter calcoaceticus im Vergleich zu anderen Carnitin-verwertenden Bakterienarten einen für ihn charakteristischen Stoffwechselweg.
    Notes: Abstract The utilization of carnitine and carnitine derivatives (O-acylcarnitines, carnitine carboxylderivatives) and structure-related trimethylammonium-compounds (betaines and nitrogen-bases) by Acinetobacter calcoaceticus was studied by means of the control of growth and the quantitative detection of metabolites. The strain grew only on l-carnitine, l-O-acylcarnitines, and γ-butyrobetaine as the sole carbon sources. The utilization of these compounds and the growth correlated with the cleavage of the C-N bond and thereby with the formation of trimethylamine. d-Carnitine was metabolized, if an additional carbon source, like l-carnitine, was present in the incubation mixture, or if the bacteria were preincubated with l-or dl-carnitine, but no growth was observed on d-carnitine as the sole carbon source. The bacteria oxidized choline to glycinebetaine in the presence of additional carbon sources, glycinebetaine itself was not assimilated. With regard to the catabolism of quaternary nitrogen compounds Acinetobacter calcoaceticus shows a different pathway in comparison with other bacterial species metabolizing carnitine.
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  • 149
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    Archives of microbiology 112 (1977), S. 239-246 
    ISSN: 1432-072X
    Keywords: Hydrogen bacteria ; Alcaligenes eutrophus H 16 ; Leucine biosynthesis ; α-Isopropylmalate synthase ; Temperature anomaly ; Cold lability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract α-Isopropylmalate (IPM) synthase, the first enzyme in the biosynthesis of l-leucine, was purified to a specific activity of 12 μmole/min x mg protein from the valine-isoleucine double auxotrophic mutant A-81 of the hydrogen bacterium Alcaligenes eutrophus H 16. The activity in crude extracts of derepressed cells was 0.106 μmoles of isopropylmalate formed per min and per mg protein. Gel electrophoresis and regel electrophoresis of the isolated main band resulted in several distinct bands, which were not altered by the additions of substrate α-ketoisovalerate, feedback inhibitor leucine or other effectors. The isoelectric points of the enzyme protein was between 3.9 and 4.0. The molecular weight was 114500 daltons and 100000 respectively in the absence and presence of the feedback inhibitor leucine. The enzyme activity depended strongly on the pH, the optimum is at pH 8.2. The enzyme was could labile and exhibits temperature anomalies.
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  • 150
    ISSN: 1432-072X
    Keywords: Phototropic bacteria ; Rhodospirillum rubrum ; Assimilatory sulfate reduction ; Adenosine-5′-phosphosulfate ; 3′-Phosphoadenosine-5′-phosphosulfate ; APS-sulfotransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Crude extracts of Rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35S) sulfate, (35S) adenosine-5′-phosphosulfate, and (35S) 3′-phosphoadenosine-5′-phosphosulfate. An enzyme fraction similar to APS-sulfotransferases from plant sources was purified 228-fold from Rhodospirillum rubrum. It is suggested here that this enzyme is specific for adenosine-5′-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5′-phosphosulfate, however, only at a rate of 1/10 of that with adenosine-5′-phosphosulfate. Further, the reaction with 3′-phosphoadenosine-5′-phosphosulfate was inhibited with 3′-phosphoadenosine-5′-phosphate whereas this nucleotide had no effect on the reaction with adenosine-5′-phosphosulfate. For this activity with adenosine-5′-phosphosulfate the name APS-sulfotransferase is suggested. This APS-sulfotransferase needs thiols for activity; good rates were obtained with either dithioerythritol or reduced glutathione; other thiols like cysteine, 2′-3′-dimercaptopropanol or mercaptoethanol are less effective. The electron donor methylviologen did not catalyze this reaction. The pH-optimum was about 9.0; the apparent K m for adenosine-5′-phosphosulfate was determined to be 0.05 mM with this so far purified enzyme fraction. Enzyme activity was increased with K2SO4 and Na2SO4 and was inhibited by 5′-AMP. These properties are similar to assimilatory APS-sulfotransferases from spinach and Chlorella.
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  • 151
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    Archives of microbiology 113 (1977), S. 215-220 
    ISSN: 1432-072X
    Keywords: Obligate psychrophile ; Maximum specific growth rate ; Cell yield ; Oxygen uptake ; Substrate affinities ; Vibrio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth characteristics of an obligately psychrophilic Vibrio sp. have been studied in a chemostat with glucose or lactose as the limiting substrate over a temperature range 0–23°C. Vibrio AF-1 has an optimum growth temperature of 15°C and maximum growth temperature which is dependent upon the carbon source. On glucose growth ceases at 20°C whereas on lactose growth continues to 23°C. Growth rate is also a function of the carbon source provided. When grown on glucose, fructose, sucrose, maltose and galactose μmax values of 0.046 h-1 at 15°C were recorded whereas on lactose, mannose, ribose and xylose μmax values of 0.020 h-1 were obtained. Substrate affinities (K s ) for the 9 sugars also fall into 2 divisions as for μmax and are temperature dependent. Those sugars which support a high growth rate have highest K s values at 0°C whereas these which give a low growth rate show maximum affinities at 15°C. Vibrio AF-1 produces the maximum cell yield (0.6 g/g sugar consumed) at temperature 〈8°C irrespective of the carbon source utilised and correlated with maximum rates of sugar uptake and minimum O2 consumption. Maintenance energy determination on glucose grown cells show that at 2° C 2% of the carbon input is used for maintenance whereas at 20°C the requirement increases to 10% of the carbon input.
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  • 152
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    Archives of microbiology 113 (1977), S. 257-264 
    ISSN: 1432-072X
    Keywords: Thiobacillus A2 ; Facultative heterotrophy ; Diauxic growth ; Sugar metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thiobacillus A2 grew on a number of organic acids, pentoses, hexoses and α-linked disaccharides, but not on β-linked disaccharides or galactosides. Growth was slow on glucose, although fast-growing strains were selectively isolated. Additive growth rates occurred on glucose and galactose; growth on glucose with fructose, pyruvate or gluconate was biphasic rather than diauxic; fructose was used preferentially over glucose; slow growth on glucose was accelerated by some disaccharides; growth on acetate, fumarate or succinate with glucose gave diauxic growth with preferential use of the acid and repression of glucose incorporation. Acetate and succinate tended to be used preferentially even with cultures grown on them in mixture with fructose or sucrose.
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  • 153
    ISSN: 1432-072X
    Keywords: Scenedesmus obliquus ; Chlorophyta ; Pigment mutant PG1 ; ζ-Carotene ; Cyclic carotenes ; Xanthophylls ; Chloroplast development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dark grown Scenedesmus obliquus strain PG1 accumulated ζ-carotene and phytoene as its major carotenoids. On illumination of dark-grown cultures in air/CO2, cyclic carotenes and xanthophylls were formed, apparently at the expense of the accumulated phytoene and ζ-carotene. This interconversion of carotenoids was accompanied by chlorophyll synthesis. In an atmosphere of nitrogen/CO2 the light-induced changes occurred more slowly and in nitrogen alone the changes were incomplete. No massive production of cyclic carotenes from the accumulated ζ-carotene was observed in cultures illuminated under anaerobic conditions.
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  • 154
    ISSN: 1432-072X
    Keywords: Schizophyllum ; Cell wall ; Fruiting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During the development of fruit bodies of the basidiomycete Schizophyllum commune, the alkali-insoluble (R glucan) and alkali-soluble (S glucan) cell wall fractions are synthesized during the entire course of morphogenesis. The water soluble glucan (WSG) is not synthesized after an early stage. There is also a relative increase in the proportion of S glucan during development which appears related to a change in the proportion of the components synthesized. Data are also presented to show that several fruiting mutants also have specific cell wall differences, and that there is a significant contribution to cell wall structure by genes which do not cause a macroscopically observable change in phenotype.
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  • 155
    ISSN: 1432-072X
    Keywords: Anacystis nidulans ; Sulphate uptake ; Osmotic shock ; Membrane potential ; Sulphate starvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sulphate uptake by Anacystic nidulans under aerobic conditions in the light was found to be sensitive to metabolic poisons, such as N, N′-dicyclohexyl-carbodiimide and carbonyl cyanide m-chlorophenyl hydrazone. It was also depressed by darkness. The sulphate absorption is an energy-dependent process. Sulphate uptake was also inhibited by chromate and selenate. Osmotic shock strongly affected sulphate uptake. This effect could be interpreted by a loss of a binding protein involved in the absorption of sulphate. Osmotic shock also depressed oxygen production in light and oxygen consumption in darkness; however, shocked cells were able to grow normally. Sulphate uptake was strongly enhanced by sulphate starvation, but this enhancement was partly prevented by chloramphenicol. Apparently sulphate starvation depressed the synthesis of a carrier involved in the transport of sulphate. During sulphate starvation the membrane potential, measured by the uptake of triphenylmethylphosphonium, increases. This may be due to changes in the membrane.
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  • 156
    ISSN: 1432-072X
    Keywords: Hydrogen cyanide biosynthesis ; Pseudomonas aeruginosa ; Phosphate effect on HCN ; Secondary metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biosynthesis of hydrogen cyanide (HCN) by a strain of Pseudomonas aeruginosa is found to be significantly influenced by inorganic phosphate. Optimum HCN production occurs when the phosphate concentration is between 1 and 10 mM. Above and below this concentration the amount of HCN produced decreases sharply and at 0.1 and 100 mM phosphate low HCN production occurs. If a culture growing at 0.1 mM phosphate and producing low HCN is shifted to 10 mM phosphate, HCN biosynthesis resumes. Experiments with chloramphenicol indicate that de novo-protein synthesis is required for the process.
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  • 157
    ISSN: 1432-072X
    Keywords: Methylococcus capsulatus ; Methane oxidation ; Methanol oxidation ; Metal binding compounds ; Acetylenic compounds ; Specific inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Inhibition studies of methane mono-oxygenase activity in whole cell suspensions of Methylococcus capsulatus (Texas) and M. capsulatus (Bath) were performed and the results compared. The inhibition pattern for M. capsulatus (Bath) was not only substantially different from the pattern obtained with M. capsulatus (Texas) but also very limited in the number of potent inhibitors specific for methane oxidation. To confirm the whole cell results of M. capsulatus (Bath) similar experiments were done using cell-free extracts. It was found that only acetylene (100% inhibition) and 8-hydroxyquinoline (71%) significantly inhibited methane oxidation, verifying the restricted inhibition pattern found with the whole cell suspensions. Eight acetylenic compounds were tested for specific inhibition of methane oxidation by whole cells and cell-free extracts of M. capsulatus (Bath). Only two compounds (acetylene and propyne) gave 100% inhibition in both cases with three other compounds (but-1-yne, but-2-yne and propyn-1-ol) giving weaker inhibitions. The inhibition pattern of methane oxidation by whole cell suspensions and cell-free extracts of M. capsulatus (Bath) is discussed and reasons for the prominent results are suggested.
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  • 158
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    Archives of microbiology 114 (1977), S. 167-170 
    ISSN: 1432-072X
    Keywords: Gas vacuoleless mutant ; Gas vesicle protein ; Blue-green alga ; Anabaena flos-aquae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Filaments without gas vacuoles arose spontaneously in the gas-vacuolate alga Anabaena flos-aquae. The non-vacuolate mutant was enriched by repeated sedimentation and subsequently cloned by microsyringe transfer. No revertants have been observed. In the gas-vacuolate wild-type alga the gas vesicle protein was clearly distinguished by gel electrophoresis as one of the ten most abundant protein species present in whole cell extracts. Electrophoresis indicated that the mutant had lost the ability to synthesize the gas vesicle protein. A second mutant partially defective in production of gas vacuoles and gas vesicle protein has been isolated.
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  • 159
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    Archives of microbiology 114 (1977), S. 175-181 
    ISSN: 1432-072X
    Keywords: Bdellovibrio bacteriovorus ; Cell division ; Cell elongation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Elongation and division of Bdellovibrio bacteriovorus were studied in axenic synchronous cultures. The cells elongate unidirectionally from one end attaining a length of several “unit cells”, and then divide into the corresponding number of cells. The length of the filament and, consequently, the progeny number, vary within the range of two to several dozen cells, according to the conditions used. A protein and a low molecular weight component are required for normal division.
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  • 160
    ISSN: 1432-072X
    Keywords: Poly-β-hydroxybutyrate ; PHB ; Acetoacetyl CoA reductase ; Zoogloea ramigera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Zoogloea ramigera I-16-M was found to contain two stereospecific acetoacetyl CoA reductases; one was NADP+-linked and d(-)-β-hydroxybutyryl CoA specific and the other was NAD+-linked and l(+)-isomer specific. The NADP+-linked enzyme, purified approximately 150-fold, had a pH optimum for the reduction of acetoacetyl CoA at 8.1, but no definite pH optimum for the oxidation of β-hydroxybutyryl CoA. The apparent Michaelis constants for acetoacetyl CoA and NADPH were 8.3 and 21 μM, respectively. The enzyme was markedly inhibited by acetoacetyl CoA at concentrations higher than 10 μM. The incorporation of [1-14C]acetyl CoA into poly-β-hydroxybutyrate (PHB) by bacterial crude extract (containing β-ketothiolase, acetoacetyl CoA reductases, enoyl CoA hydratases and PHB synthases) or by a system reconstituted from purified preparations of β-ketothiolase, acetoacetyl CoA reductase and PHB synthase, was observed only in the presence of NADPH, but not NADH. Among various enzymes involved in PHB metabolism, only the specific activity of glucose 6-phosphate dehydrogenase was elevated 5-fold within 2 h after the addition of glucose to the cells grown in the basal medium. These findings suggest that, in Z. ramigera I-16-M, acetoacetyl CoA is directly reduced to d(-)-β-hydroxybutyryl CoA by the NADP+-dependent reductase, and PHB synthesis is at least partially controled by NADPH availability through glucose 6-phosphate dehydrogenase.
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  • 161