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At least 19 recordsLinked to original sources
PubMed1978

Blood-reduced glutathione, pyruvic acid, citric acid, ceruloplasmin oxidase activity and certain mineral changes in diabetes mellitus before and after treatment.

In maturity onset diabetes the blood levels of total blood keto acids in terms of pyruvic, serum citric, calcium are significantly higher than in normal adults, while there is a decrease in reduced-blood glutathione, serum zinc, potassium and sodium levels. There were no significant differences between diabetes and normal adults in the serum levels of copper, ceruloplasmin oxidase activity, iron and magnesium.

Adult↗
PubMed1979

[The long-term effect of various hormonal contraceptives on the excretion of sodium, potassium, calcium, magnesium, chloride, phosphorus, uric acid, oxalic acid, citric acid, sulfate and lysozyme in the 24 hour urine].

The influence of a long-term application of 4 different hormonal contraceptives on the excretion of various constituents of the urine was examined. A reverse effect after stoppage of the medication is to be established in none of the other parameters with the exception of calcium.

Calcium↗
PubMed1976

Effect of acetic and trans-aconitic acids on citric acid production by Aspergillus niger.

The effect of acetic and trans-aconitic acids on citric acid production by A. niger at different pH values was studied. The presence of acetic acid at pH 2 prevented spore germination, while it decreased the fungal growth and citric acid production at other pH values. In the presence of trans-aconitic acid the inhibition was less marked at lower than at higher pH values.

Acetates↗
PubMed1979

[Analysis of citric acid and citrates. Citric acid and urolithiasis].

In the first part the physico-chemical, analytic chemical and physiologic biochemical properties of the citric acid are discussed. In the second part the author enters the role of the citric acid in the formation of uric calculi. In the third part is reported on the individual methods of the determination of citric acid and the method practised in the author's laboratory is described.

Chemical Phenomena↗
PubMed1976

Replenishment and depletion of citric acid cycle intermediates in skeletal muscle. Indication of pyruvate carboxylation.

The effects of various substrates on the concentrations of free amino acids, citric acid cycle intermediates and acylcarnitines were studies in perfused hindquarter of rat in presence of glucose and insulin in order to assess regulatory mechanisms of the level of citric acid cycle intermediates in skeletal muscle. 1. Acetate and acetoacetate effected a significant increase in the level of citrate cycle intermediates and accumulation of acetylcarnitine. These changes were accompanied by a reduction in the level of alanine. The concentration of AMP was significantly elevated. 2. Muscle mitochondria fixed 14CO2 in the presence of pyruvate. The products were identified as malate or citrate when whole and disintegrated mitochondria were used respectively. The fixation was greatly stimulated by acetylcarnitine. 3. Acetylcarnitine inhibited the production of pyruvate from malate by muscle mitochondria. 4. Perfusion with 2-oxoisocaproate and 2-oxoisovalerate promoted increases in the level of citric cycle intermediates, a drop in both alanine and glutamate, and accumulation of branched-chain acylcarnitines. 2-Oxoisocaproate also caused a reduction of alanine released from the muscle. 5. Perfusion with leucine and valine did not change the concentration of citric acid cycle intermediates, but elevated glutamate and still more the concentration of alanine. 6. It is concluded that citric cycle intermediate level in the perfused resting muscle is modified by a) conditions which change the concentration of acetyl-CoA and thereby modify the rate of pyruvate carboxylation and decarboxylation of malate via malic enzyme b) conditions which change the concentration of pyruvate cause changes in alanine and cycle intermediates in the same direction via transamination reactions c) conditions which change the concentrations of 2-oxoacids which are converted to cycle intermediates via oxidation.

Acetyl Coenzyme A↗
PubMed1979

Manganese deficiency leads to elevated amino acid pools in citric acid accumulating Aspergillus niger.

Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method. Studies on the mycelial content of several nitrogenous compounds under manganese sufficient and deficient conditions showed that manganese deficiency resulted in lower amino acid pool sizes during trophophase and considerable accumulation during idiophase, and in a reduction of the protein and nucleic acid contents. Addition of cycloheximide to mycelia grown with sufficient manganese also caused an elevation of free amino acid pool sizes, thus indicating that impairment of protein synthesis by manganese deficiency is responsible for the observed rise in amino acid concentration. Furthermore it was observed that the manganese deficient mycelia excreted high amounts of all amino acids suggesting that manganese deficiency may also affect membrane permeability.

Amino Acids↗
PubMed1975

Regulation of the dicarboxylic acid part of the citric acid cycle in Bacillus subtilis.

The regulation of alpha-ketogluterate dehydrogenase, succinate dehydrogenase, fumarase, malate dehydrogenase, and malic enzyme has been studied in Bacillus subitilis. The levels of these enzymes increase rapidly during late exponential phase in a complex medium and are maximal 1 to 2 h after the onset of sporulation. Regulation of enzyme synthesis has been studied in the wild type and different citric acid cycle mutants by adding various metabolites to the growth medium. Alpha-ketoglutarate dehydrogenase is induced by glutamate or alpha-ketoglutarate; succinate dehydrogenase is repressed by malate; and fumarase and malic enzyme are induced by fumarate and malate, respectively. The addition of glucose leads to repression of the citric acid cycle enzymes whereas the level of malic enzyme is unaffected. Studies on the control of enzyme activities in vitro have shown that alpha-ketoglutarate dehydrogenase and succinate dehydrogenase are inhibited by oxalacetate. Enzyme activities are also influenced by the energy level, expressed as the energy charge of the adenylate pool. Isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, and malic enzyme are inhibited at high energy charge values, whereas malate dehydrogenase is inhibited at low energy charge. A survey of the regulation of the citric acid cycle in B.subtilis, based on the present work and previously reported results, is presented and discussed.

Adenine Nucleotides↗
PubMed1977

Lack of effect of ascorbic and citric acids on calcium metabolism of chickens.

Five experiments were carried out in which various levels of calcium and ascorbic acid or citric acid were fed to adult male chickens, young chickens, or young coturnix. Observations were made on body weight, feed efficiency, plasma calcium and tibia mineral content. One percent dietary ascorbic acid had no adverse effect on body weight, tibia ash or tibia calcium content of adult male chickens over a 224-day period, even at calcium levels as low as 0.026% of the diet. In growing chicks, body weight and plasma calcium and tibia mineral content varied with the calcium level of the diet, but were not influenced by ascorbic acid even at 0.65% of the diet. Citric acid at the same molar level was also ineffective in altering calcium metabolism in growing chickens. Growing coturnix showed differences in growth and tibia ash content with 0.4% and 0.85% calcium, but there were no pronounced effects caused by dietary ascorbic acid. There is no evidence in this work that these relatively high levels of ascorbic acid or citric acid have any adverse effect on calcium metabolism because of their chelating properties.

Animals↗
PubMed1976

Fatty acid oxidation, substrate shuttles, and activity of the citric acid cycle in hepatocellular carcinomas of varying differentiation.

Fatty acid oxidation, reconstituted substrate shuttles, and the activity of the citric acid cycle were studied in mitochondria isolated from Becker transplantable hepatocellular carcinoma H-252 AND Host livers, and the results were compared with those obtained with Morris hepatomas 7288CTC and 5123C. Whereas the activities of the malate-aspartate and the alpha-glycerophosphate shuttles were only slightly lower than those of host livers, the activity of the fatty acid shuttle was much lower in H-252 mitochondria. Oxygen uptake and CO2 production associated with the oxidation of fatty acids was much lower in tumors H-252 and 7288CTC, compared with host livers, whereas tumor 5123C mitochondria show a high capacity to oxidize fatty acids. Ketogenesis and beta-hydroxybutyrate dehydrogenase activity were also lower in tumor H-252 mitochondria. However, neither oxygen uptake associated with the oxidation of other respiratory substrates nor CO2 production from succinate or malate was strikingly elevated in these tumors. These factors suggest that the respiratory phosphorylation chain and activity of the citric acid cycle are fully functional in tumors H-252 and 7288CTC. The defects responsbile for the lower rates of fatty acid oxidation in these tumors probably involves the beta-oxidation pathway, as well as the activation of fatty acids. The impairment of fatty acid oxidation may explain the lower activity of the reconstituted fatty acid shuttle for transporting reducing equivalents into H-252 mitochondria. The different properties with regard to fatty acid oxidation in Morris hepatoma 5123C, compared with those in Becker H-252- AND Morris hepatoma 7288CTC, may reflect the different extent of differentiation in these tumors, the former being a slow-growing, well-differentiated tumor, whereas the latter represent tumors that are less differentiated and of more rapid growth rate.

Animals↗
PubMedDate not supplied

[Respiratory cyanide resistance in Candida lipolytica and the supersynthesis of citric acids].

The interrelationship between the cyanide resistance of respiratio and the process of citric acid synthesis was studied with various strains of Candida lipolytica. When the synthesis of citric acids was intensive, the respiration of cells was almost entirely inhibited by cyanide. The respiration became cyanide resistant only when the biosynthesis of citric acids was over. Induction of the cyanide resistance of respiration with antimycin A stopped the biosynthesis of citric acids. The cyanide resistance of respiration in yeast cultures incapable of considerable production of citric acids was displayed when the growth ceased. There was a strong direct correlation between the rate of citric acid synthesis and the degree of inhibition of the respiration by cyanide. It was concluded therefore that the process of citric acid overproduction could reset the reduction equivalents, thus making unnecessary the cyanide resistant pathway of electron transport.

Antimycin A↗
PubMed1979

Thermal characterization of citric acid solid dispersions with benzoic acid and phenobarbital.

The glass transition temperatures of citric temperatures of citric acid glass were determined by differential scanning calorimetry to be 10.2 and 13.5 degrees for in situ and bulk-prepared samples, respectively. Mechanical stress on citric acid glass induced foci for crystallization. Benzoic acid addition to citric acid glass decreased its glass transition temperature while phenobarbital addition increased its glass transition temperature, the latter forming a glass solution.

Benzoates↗
PubMed1992

The effect of citric acid application on periodontally involved root surfaces. 1. An in vitro light microscopic study.

This study investigated the effect of citric acid application on periodontally involved root surfaces. Forty periodontally involved teeth were randomly divided into four groups of ten teeth each: no treatment, citric acid treatment, root planing alone, and root planing in conjunction with citric acid treatment. Ten nondiseased, untreated teeth served as controls. After treatment, each tooth was split along its long axis; half was examined under light microscopy and half under scanning electron microscopy (part II of the paper). Light microscopy revealed that the effects obtained by scaling and root planing were not altered after citric acid application. Moreover, the cementum layer was not entirely removed without careful and thorough planing of the root surface. Citric acid application alone had no effect on the diseased root surface. Citric acid did not penetrate the dentinal tubules, nor did it alter the collagen content of the roots obtained by scaling and root planing.

Analysis of Variance↗
PubMed1992

Microbial production of citric acid from salad oil.

Strain CCU-U2-N4-41 was derived from a wild strain of yeast CCU-087. This strain can produce large amounts of citric acid from salad oil. The optimal medium for citric acid production is one liter of medium containing salad oil 100 g, yeast extract 2.0 g, CH3COONH4 3.0 g, KH2PO4 5.0 g, MgSO4 500 ppm, 1 ppm each of MnSO(4).5 H2O and CuSO(4).2 H2O, pH: 7.0. The optimal culture conditions are: temperature: 28 degrees C; agitation: 110 rpm; 100 mL medium in 500-mL Hinton flask; 1.5% CaCO3 added after 12 hr incubation. With 96 hr cultivation 71.2 g/L of citric acid can be produced. Citric acid produced was compared with authentic citric acid by melting point determination, IR, NMR and Mass. From the spectra, it was found that they were identical.

Citrates↗
PubMed1979

[Fructose and citric acid content in the sperm of stud males with forms of impotencia generandi].

Fructose and citric acid content was investigated in the sperm of 27 bulls with anamnesis data for "low quality sperm". The bulls were used as breeding males in various stations for artificial insemination. Three forms of Imp. generandi are described and several grades of Oligokinospermia are differentiated. Changes in fructose and citric acid quantity differed in degree in the various forms of Imp. generandi described. Fructose and citric acid value in I and II grade Oligokinospermia were insignificantly lower than the low limit of these indices observed in bulls with normal spermoproduction. Correlation between the changes observed is positive, slight, insignificant or entirely missing. Fructose content is insignificantly lower in cases of III and IV grade Oligokinospermia and in Akinospermia, while citric acid content is reduced only in Akinospermia. The correlation between the changes is positive , high and significant. Fructose reduction in bull's semen below 400.0 mg% and of citric acid below 500.0 mg% in case of negative data for inflammatory changes in vesiculae seminalis is a diagnostic symptom for disfunction of vesiculae seminalis. More considerable changes occur in fructose values.

Animals↗
PubMed1978

[Kinetics of citric acid production in Candida lipolytica].

The kinetics of citrate and isocitrate accumulation by Candida lipolytica has been studied, with special emphasis of the carbon sources glucose and n-alkanes and the shifts from one carbon source to the other. The accumulation of the citric acids starts with the beginning of ideophase. Trophophase and ideophase behaviour is in parts different. Ideophase behaviour may be influenced by exogenic factors during growth. From the course of the curves for the citric acids two phases can be distinguished: The specific production rate of the first phase is higher than in the second phase (pi1 approximately 0.19 h-1; pi2 approximately 0.14 h-1). The influence of the carbon source on the course of the curves and the numeric value for the specific production rate is negligible. Alcane grown cells accumulate citric acids from added glucose and left-over n-alcanes simultaneously. When both substrates are added from the beginning only glucose is taken up for growth, for citric acid production both substances are utilized simultaneously. Glucose grown cells do not utilize alcanes for production of citric acids. Citric acids are accumulated only as long as glucose is available. Alcane uptake starts after addition of a nitrogen source.

Aerobiosis↗