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At least 37 records · Page 2Linked to original sources
PubMed1979

[Dynamics of the NADP+ and NAD+ levels in the mycelium of P. nigricans Thom strains of varying productivity depending on the carbon source].

The levels of NADP+ and NAD+ in the mycelium of the highly productive strain 117 and low productive strain B of P. nigricans were studied by the 2nd, 5th, 9th and 13th days of development on the mineral medium in the presence of glucose, succinate or acetate. It was found that at the beginning of the growth the levels of NADP+ in both strains in the presence of the same carbon source were the same, just as the levels of NAD+ in the presence of glucose or succinate. The same strain had different levels of NADP+ in the presence of different carbon sources. The levels of NAD+ depended on both the carbon source and the strain. In the presence of glucose both nucleotides were accumulated by the end of the culture development and in greater amounts by strain 117. In the presence of succinate the maximum levels were observed at the beginning of the culture growth, while in the presence of accetate the maximum levels were recorded by the end of the culture development (strain 117) and by the 19th day (strain B). It is supposed that NAD+ is transformed into adenylates in the fungi.

Acetates↗
PubMed1978

Biosynthesis and regulation of fructose-1,6-bisphosphatase and phosphofructokinase in Saccharomyces cerevisiae grown in the presence of glucose and gluconeogenic carbon sources.

The mode of synthesis and the regulation of fructose-1,6-bisphosphatase (Fbpase), a gluconeogenic enzyme, and phosphofructokinase (PFK), a glycolytic enzyme, were investigated in Saccharomyces cerevisiae after growth in the presence of different concentrations of glucose or various gluconeogenic carbon sources. The activity of FBPase appeared in the cells after the complete disappearance of glucose from the growth medium with a concomitant increase of the pH and no significant change in the levels of accumulated ethanol. The appearance of FBPase activity following glucose depletion was dependent upon the synthesis of protein. The FBPase PFK were present in glucose-, ethanol-, glycerol-, lactate-, or pyruvate-grown cells; however, the time of appearance and the levels of both these enzymes varied. The FBPase activity was always higher in 1% glucose-grown cells than in cells grown in the presence of gluconeogenic carbon sources. Phosphoglucose isomerase activity did not vary significantly. Addition of glucose to an FBPase and PFK synthesizing culture resulted in a complete loss, followed by a reappearance, of PFK activity. In the presence of cycloheximide the disappearance of glucose and the changes in the levels of FBPase and PFK were decreased significantly. It is concluded that S. cerevisiae exhibits a more efficient synthesis of FBPase after the exhaustion of glucose compared to the activity present in cells grown in the presence of exogenous gluconeogenic carbon sources. Two metabolically antagonistic enzymes, FBPase and PFK, are present during the transition phase, but not during the exponential phase, of growth, and the decay or inactivation of these enzymes in vivo may be dependent upon a glucose-induced protease activity.

Bacterial Proteins↗
PubMed1977

Acetate as a carbon source for lipid synthesis in cultured cells.

Lipid synthesis from acetate and glucose has been studied in fibroblast cultures grown in lipid free medium containing various concentrations of acetate and glucose. Their role in lipid synthesis was evaluated by comparing the specific activities of total cell lipid, and sterol and fatty acid subfractions, to that of the carbon source in the medium. When glucose was present at 1000 microgram/ml (5.6 mM) and acetate at 100 microgram/ml (1.2 mM), the majority of the total cell lipid and subfractions were derived from glucose. As acetate concentrations increased, lipid synthesis from acetate increased, and glucose declined as a carbon source; in cells grown in the presence of 1000 microgram/ml (12 mM) acetate more of the lipid was derived from acetate than from glucose. When acetate was present at 1000 microgram/ml (12 mM) and glucose was varied from 1000 to 200 microgram/ml (5.6 to 1.1 mM), the relative amount of lipid synthesis from acetate was further increased. The data indicate that acetate can serve as a significant carbon source for lipid synthesis in cultured fibroblasts when it is presented to the cells at high extracellular concentrations relative to glucose.

Acetates↗
PubMed1979

Effects of carbon sources on antibiotic resistance in Pseudomonas aeruginosa.

The metabolism of branched-chain amino acids, branched-chain acyl derivatives, d-glucose, l-glutamate, and Mueller-Hinton medium was investigated to determine their effects on the growth, lipid composition, and antibiotic susceptibility of Pseudomonas aeruginosa. The unsaturated fatty acid content of the readily extractable lipids was altered by growth on selected branched-chain amino acids and their acyl derivatives. Bacteria grown on branched-chain acyl derivatives became more susceptible to polymyxin B and colistin. The effect acyl derivatives had on increasing susceptibility was also manifest in mixed media which contained both an acyl derivative and a carbon source which did not increase susceptibility. Growth on branched-chain amino acids gave mixed results which were dependent on a number of factors, including unique manifestations of individual amino acids, growth conditions, and availability of other carbon sources. The cultural conditions which altered susceptibility to polymyxin antibiotics did not correlate with similar effects on susceptibility to carbenicillin and gentamicin. An adaptive resistance to polymyxin B was observed when the sole carbon source was d-glucose or l-glutamate.

Amino Acids↗
PubMed1978

Increased antimetabolite sensitivity with variation of carbon source during growth.

In Serratia marcescens, analogs of leucine (norleucine), methionine (alpha-methylmethionine), histidine (3-amino-1,2,4-triazolealanine), tyrosine (p-aminophenylalanine), and tryptophan (7-methylindole) are conditional inhibitors of growth; inhibition occurs during the metabolism of some carbon sources but not with others. A further increase in sensitivity to growth inhibition by these analogs can be accomplished through the use of particular combinations of carbon sources present in the inoculum and in the subsequent analog-containing culture medium. Variable sensitivity to analog-mediated inhibition of growth observed during growth on glucose, glycerol, fructose, or citrate correlated inversely with the intracellular pool sizes of the amino acids cognate to the analogs used. The above-cited results, in conjunction with previous results obtained with Pseudomonas aeruginosa and Bacillus subtilis, involve diverse biochemical pathways and suggest that nutritional manipulation to alter the pattern of carbon flow in microorganisms is a generally useful means to accomplish increased sensitivity to growth inhibition by metabolite analogs.

Amino Acids↗
PubMedDate not supplied

[Effect of various carbon sources on cholinesterase formation by Arthrobacter simplex var. cholinesterasus].

The effect of carbohydrates, aromatic alcohols, choline and acetylcholine on the biomass production and biosynthesis of choline esterase was studied with Arthrobacter simplex var. cholinesterasus. Fructose was found to be the best carbon source for the biomass accumulation and synthesis of choline esterase. Almost the same amount of the enzyme was produced on media with glucose and maltose as on the medium with fructose though the biomass yield was much lower. On the contrary, the biomass production was higher on media with acetylcholine and ethanol, but synthesis of the enzyme was inhibited. Choline was not assimilated by the culture. Differences in assimilation of glucose and fructose by the culture were found to depend on their concentration and the presence, or absence, of the inductor (acetylcholine) in the medium. Fructose was assimilated by the culture almost completely irrespective of its concentration and the presence of the inductor in the medium. Glucose was assimilated partly, best of all at a concentration of 0.5%. An increase of the concentration to 1% inhibited assimilation of glucose by the organism though had no effect on the biomass production and synthesis of the enzyme. The inductor stimulated assimilation of glucose by a factor of 1.5. Synthesis of choline esterase on the medium with acetylcholine at a concentration of 1% was increased more than twofold upon addition of glucose at a concentration of 0.1%. Biosynthesis of the enzyme rised with glucose concentration though accumulation of the biomass was inhibited. Inhibition of choline esterase synthesis on the medium with acetylcholine as a sole carbon source is due to a lack of energy and the absence of synthesis of carbon compounds which are acceptors of acetyl and methyl groups.

Acetylcholine↗
PubMed1978

Evolution of ethylene by Saccharomyces cerevisiae as influenced by the carbon source for growth and the presence of air.

Effects of the carbon source and oxygen on ethylene production by the yeast Saccharomyces cerevisiae have been studied. The amounts of ethylene evolved by the yeast culture were less than those detected in the blank (an equal volume of uninoculated medium), suggesting a net absorption of ethylene by the yeast cells. Addition of glucose to the lactate-grown yeast culture induced ethylene production. This glucose-induced stimulation of ethylene production was inhibited to a great extent by cycloheximide. Results suggested that the yeast cells in the presence of glucose synthesized an ethylene precursor and passed it into the medium. The conversion of this precursor to ethylene might be stimulated by oxygen. The fact that ethylene was produced by the yeast growing anaerobically and also by respiration-deficient mutants isolated from the wild-type yeast suggested that mitochondrial ATP synthesis was not an absolute requirement for ethylene biogenesis.

Anaerobiosis↗
PubMed1979

Arylsulfatase in Salmonella typhimurium: detection and influence of carbon source and tyramine on its synthesis.

Arylsulfatase synthesis was shown to occur in Salmonella typhimurium LT2. The enzyme had a molecular weight of approximately 50,000 and was separated into five forms by isoelectrofocusing. The optimal pH for substrate hydrolysis was pH 6.7, with Michaelis constants for nitrocatechol sulfate and nitrophenyl sulfate being 4.1 and 7.9 mM, respectively. Enzyme synthesis was strongly influenced by the presence of tyramine in the growth medium. The uptake of [14C]tyramine and arylsulfatase synthesis were initiated during the second phase of a diauxie growth response, when the organism was cultured with different carbon sources. Adenosine 3',5'-cyclic monophosphoric acid enhanced the uptake of tyramine and the levels of arylsulfatase synthesized. However, the addition of glucose and glycerol to organisms actively transporting tyramine and synthesizing enzyme caused a rapid inhibition of both of these processes. This inhibition was not reversed by adding adenosine 3',5'-cyclic monophosphoric acid. The results suggest that the effect of the carbon source on tyramine transport and arylsulfatase synthesis may be explained in terms of inducer exclusion.

Ammonium Chloride↗
PubMed1977

Effect of carbon source and the role of cyclic adenosine 3',5'-monophosphate on the Caulobacter cell cycle.

The expression of cell cycle events in Caulobacter crescentus CB13 has been shown to be associated with regulation of carbohydrate utilization. Growth on lactose and galactose depends on induction of specific enzymes. Prior growth on glucose results in a delay in enzyme expression and cell cycle arrest at the nonmotile, predivisional stage. Dibutyryl cyclic adenosine 3',5'-monophosphate (AMP) was shown to stimulate expression of the inducible enzymes and, thus, the initiation of the cell cycle. beta-Galactosidase-constitutive mutants did not exhibit a cell cycle arrest upon transfer of cultures from glucose to lactose. Furthermore, carbon source starvation results in accumulation of the cells at the predivisional stage. The cell cycle arrest therefore results from nutritional deprivation and is analogous to the general control system exhibited by yeast (Hartwell, Bacteriol. Rev. 38:164-198, 1974; Wolfner et al., J. Mol. Biol. 96:273-290, 1975), which coordinates cell cycle initiation with metabolic state. Transfer of C. crescentus CB13 from glucose to mannose did not result in a cell cycle arrest, and it was demonstrated that this carbon source is metabolized by constitutive enzymes. Growth on mannose, however, is stimulated by exogenous dibutyryl cyclic AMP without a concomitant increase in the specific activity of the mannose catabolic enzymes. The effect of cyclic AMP on growth on sugars metabolized by inducible enzymes, as well as on sugars metabolized by constitutive enzymes, may represent a regulatory system common to both types of sugar utilization, since they share features that differ from glucose utilization, namely, temperature-sensitive growth and low intracellular concentrations of cyclic guanosine 3',5'-monophosphate.

Bacteria↗
PubMed1977

Production of large amounts of acetate during germination of Bacillus megaterium spores in the absence of exogenous carbon sources.

When Bacillus megaterium spores germinate in the absence of an exogenous carbon source, the first minutes of germination are accompanied by production of large amounts (approximately 70 nmol/mg of dry spores) of acetate and much smaller amounts of pyruvate and lactate. The majority of these compounds are excreted into the medium. Exogenous pyruvate and alanine are also converted to CO2 and acetate by germinating spores, presumably by using the pyruvate dehydrogenase that is present in dormant spores. These data suggest that the 3-phosphoglyceric acid stores in the dormant spore and alanine generated by proteolysis early in germination can be catabolized to acetate during germination with production of large amounts of reduced nicotinamide adenine dinucleotide, acetyl coenzyme A, and adenosine 5'-triphosphate.

Acetates↗
PubMed1975

On the regulation of adenosine 3', 5'-monophosphate synthesis in bacteria. I. Effect of carbon source variation on cyclic AMP synthesis in Escherichia coli B/r.

1. The effect of carbon source variation in bacterial growth media on their growth rate, inducible enzyme and cyclic AMP synthesis was examined: an inverse relationship between the culture's growth rate and its differential rate of inducible enzyme (tryptophanase and beta-galactosidase), and cyclic AMP synthesis was found. 2. The effect of the culture's growth phase on its sensitivity or resistance to glucose catabolite repression was determined in the wild type and a catabolite insensitive mutant (ABDROI): the wild type's sensitivity to glucose repression was not affected, whereas the insensitivity of the mutant was found to be limited to its early logarithmic phase of growth. At late log, or stationary phase, the mutant was found to be sensitive to glucose repression. 3. Examination of the kinetics of glucose uptake by the mutant, using alpha-[1 4-C] methyl-glucoside showed evidence for two transport systems each with a different affinity to glucose. A low affinity transport system (apparent Km of 3.4-10-minus 5 M) which appears mostly at the early logarithmic phase of growth. A high affinity transport system (apparent Km of 1.2-10-minus 5 M) which appears mostly at the late log and stationary phases of growth. 4. The effect of the culture density variation on its sensitivity to glucose repression showed that sensitivity to glucose catabolic repression is primarily a reflection of the formation of an allosteric effector molecule between glucose and its specific transport molecule which in turn regulates the activity of the adenylate cyclase.

Allosteric Regulation↗
PubMed1978

Antigenic variation and increase in pathogenicity in Pseudomonas aeruginosa as a result of growth on glucose or N-hexadecane as sole carbon source.

When Pseudomonas aeruginosa is grown on glucose as opposed to n-hexadecane as the sole carbon source, the antigenicity, virulence, and protein composition of the outer membrane are altered. The hydrocarbon-grown cells demonstrate a 3-log increase in virulence over the glucose-grown cells (in mice). There also appears to be an additional protein present in the outer membrane of the n-hexadecane-grown cells. This protein may contribute to the observed antigenic differences between the two cell types.

Animals↗
PubMed1975

Biosynthesis of branched-chain amino acids in yeast: effect of carbon source on leucine biosynthetic enzymes.

The three enzymes in the leucine biosynthetic pathway of yeast do not exhibit coordinate repression and derepression in response to the carbon source available in the culture medium. Growth in an acetate medium results in derepression of the first enzyme in the pathway, alpha-isopropylmalate synthase, and repression of the second two enzymes, alpha-isopropylmalate isomerase and beta-isopropylmalate dehydrogenase, relative to the levels found in glucose-grown cells. The role of endogenous leucine pools as a mediator of these differences was investigated. The leucine pools did not differ significantly between acetate-grown and glucose-grown cells. However, an elevated endogenous leucine pool, caused by exogenous leucine in the growth medium, did decrease the rate of decay of alpha-isopropylmalate synthase activity observed when acetate-grown cells were shifted to glucose. Evidence is provided suggesting that an elevated endogenous leucine pool may increase the in vivo stability of alpha-isopropylmalate synthase under several different conditions. Studies on the kinetics of alpha-isopropylmalate synthase decay in vivo and sensitivity to leucine inhibition indicate that there are two classes of the enzyme in acetate-grown yeast cells.

Acetates↗
PubMed1976

Effect of different carbon sources on the biosynthesis of polyunsaturated fatty acids of alpha-linolenic acid family in culture of minimal deviation hepatoma 7288 C cells.

The effect of three different carbon sources on the biosynthesis of polyunsaturated fatty acids of the alpha-linolenic acid series was investigated in hepatoma tissue culture (HTC) cells. Alpha linolenic acid was converted to higher homologs by a desaturating route that synthetized mainly 18:4 (delta6, 9, 12, 15), 20:4 (delta8, 11, 14, 17) and 20:5 (delta5, 8, 11, 14, 17) and an elongating route that produced 20:3 (delta11, 14, 17) and 20:4 (delta5, 11, 14, 17) acids. "Fasting" decreased both biosynthetic routes whereas glucose reactivated only the elongating pathway. Lactabumin hydrolysate enhanced significantly only the desaturating route whereas glycerol was inactive. Glucose and aminoacids increased similarly the incorporation of labeled alpha linolenic acid in the cells. The results are independent of hormonal effects.

Carcinoma, Hepatocellular↗
PubMed1979

Effect of carbon sources on the rates of cyclic AMP synthesis, excretion, and degradation, and the ability to produce beta-galactosidase in Escherichia coli.

We have determined the rates of adenosine 3',5'-cyclic monophosphate (cAMP) synthesis, excretion, and degradation, and the cAMP pool size in Escherichia coli grown on various carbon sources. We have found that the cAMP pool size increases in approximate proportion to increases in the cAMP synthetic rate. Although the combined rate of excretion and degradation of cAMP is in approximate proportion to the cAMP pool size, no such regular relationship is seen between the cAMP pool size and either the excretion rate or the degradation rate. Using a method which we have developed for determining the cellular efficiency of enzyme production (termed 'cellular' rate), we have reexamined the relationship between cAMP pool size and the rate of beta-galactosidase production. Although there exists an overall trend of increasing rate of beta-galactosidase production with increasing cAMP pool size, large variations in the rates of beta-galactosidase production are seen even under culture conditions which yield similar cAMP pool sizes. This suggests that the intracellular level of cAMP cannot be the unique regulator of beta-galactosidase production.

Culture Media↗
PubMedDate not supplied

[Kinetics of Candida lipolytica yeast growth and biosynthesis of alpha-keto acids with thiamine deficiency in media with different carbon sources].

The growth kinetics of Candida lipolytica on glucose, acetate and hexadecane was studied in batch cultures at thiamine deficiency. The growth at the deceleration phase is of a linear character. The transition from the exponential phase to the linear one is accompanied with the accumulation of alpha-keto acids in the cultural broth, which is also observed in the stationary phase. The rate of acid production in the linear phase increases as the specific growth rate decreases, and reaches the maximum value in media with different carbon sources at mu = 0.01--0.06 h-1. Apparently, the deceleration of growth is due to a decrease in the activity of a thiamine-dependent enzyme (pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase or transketolase) which is a limiting point of biosynthetic processes. Here, a linear growth is determined by the constant activity of this enzyme per unit volume of the cultural broth which, in turn, depends on the constant concentration of the coenzyme, thiamine diphosphate, in the same volume.

Acetates↗
PubMed1977

Multiple-carbon-source-limited growth kinetics of a marine coryneform bacterium.

The steady-state growth rate of a marine isolate was related to the concentrations of several carbon and energy source substrates when these substrates limited growth simultaneously in continuous culture. Glucose limitation was characterized by a threshold of 0.21 mg/liter for growth, a half-maximal growth rate at 0.48 mg/liter, U-shaped curves in extractable pool concentration-versus-growth velocity plots, and slow maximal growth rates. Arginine addition reduced the glucose threshold to 0.008 mg/liter, more than doubled the maximal growth rate, and stabilized pool concentrations at low growth rates. Addition of a third substrate, glutamate, caused further reduction of the glucose concentration a steady state. Maximal reduction of the glucose concentration was effected by adding a mixture of 20 amino acids. Steady-state limiting nutrient concentration was dependent on the specific identity of the auxiliary nutrients and on the concentration ratio at which they were supplied. When glucose was supplemented with an equal quantity of an amino acid mixture, the external steady-state glucose remained below 10 mug/liter. When 1 mug of glucose was added to a 2.5-mg/liter amino acid mixture, at least 70% of it was consumed at steady state in spite of the threshold observed. Lack of crossover between metabolic pathways, suggested by the absence of glucose carbon in pool glutamate of arginine-glucose-grown cells, may have been partly responsible for the mixed carbon source stimulation of nutrient accumulation observed. The affinity observed is sufficient to account for normal growth at a total organic substrate concentration of only 0.11 mg/liter when supplied from a suitable mixture.

Amino Acids↗
PubMedDate not supplied

[Biosynthesis of citric and isocitric acids by the wild-type and mutant strains of Candida lipolytica in media containing different carbon sources].

Experiments were carried out to examine the capacity of two strains of Candida lipolytica, producing citric and isocitric acids in the alkane and glucose containing media, to grow on different two- and three-carbon compounds. The strains did not grow on oxalate, glyoxalate, glycolate, malonate or propionate. When cultivated in the media containing acetate, ethanol, glycerol, glucose or hexadecane, supersynthesis of the acids started after complete consumption of the nitrogen source and resultant delay of the culture growth. Either strain discharged the two acids in a proportion that depended on the strain nature and the type of the carbon source. The mutant strain produced only citrate while the wild-type synthesized both citrate and isocitrate, the ratio of which was related to the nature of the carbon source utilized.

Candida↗