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At least 271 records · Page 15Linked to original sources
PubMed1993

Effect of Different Carbon Sources on Relative Growth Rate, Internal Carbohydrates, and Mannitol 1-Oxidoreductase Activity in Celery Suspension Cultures.

Little information exists concerning the biochemical route of mannitol catabolism in higher plant cells. In this study, the role of a recently discovered mannitol 1-oxidoreductase (MDH) in mannitol catabolism was investigated. Suspension cultures of celery (Apium graveolens L. var dulce [Mill.] Pers.) were successfully grown on nutrient media with either mannitol, mannose, or sucrose as the sole carbon source. Cell cultures grown on any of the three carbon sources did not differ in relative growth rate, as measured by packed cell volume, but differed drastically in internal carbohydrate concentration. Mannitol-grown cells contained high concentrations of mannitol and extremely low concentrations of sucrose, fructose, glucose, and mannose. Sucrose-grown cells had high concentrations of sucrose early in the growth cycle and contained a substantial hexose pool. Mannose-grown cells had a high mannose concentration early in the cycle, which decreased during the growth cycle, whereas their internal sucrose concentrations remained relatively constant during the entire growth cycle. Celery suspension cultures on all three carbon substrates contained an NAD-dependent MDH. Throughout the growth cycle, MDH activity was 2- to 4-fold higher in mannitol-grown cells compared with sucrose- or mannose-grown cells, which did not contain detectable levels of mannitol, indicating that MDH functions pre-dominantly in an oxidative capacity in situ. The MDH activity observed in celery cells was 3-fold higher than the minimum amount required to account for the observed rate of mannitol utilization from the media. Cultures transferred from mannitol to mannose underwent a decrease in MDH activity over a period of days, and transfer from mannose to mannitol resulted in an increase in MDH activity. These data provide strong evidence that MDH plays an important role in mannitol utilization in celery suspension cultures.

Journal Article↗
PubMed2001

Growth of moderately halophilic bacteria isolated from sea water using phenol as the sole carbon source.

Moderately halophilic bacteria utilizing phenol as the sole carbon source were isolated by selective enrichment from sea water. The isolate (Gram-negative motile rods) was identified as Deleya venusta. It grew well in the presence of up to 1600 mg/L of phenol and 8% NaCl under aerobic conditions. When the cells were treated with chloramphenicol prior to the addition of phenol they did not utilize added phenol, even after prolonged incubation. Thus, the enzymes necessary for phenol metabolism appeared to be inducible.

Arthrobacter↗
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↗
PubMed2005

Subcellular localization of the cyclin dependent kinase inhibitor Sic1 is modulated by the carbon source in budding yeast.

The cyclin dependent kinase inhibitor Sic1 and the cyclin Clb5 are essential regulators of the cyclin dependent kinase Cdc28 during the G1 to S transition in budding yeast. Yeast enters S phase after ubiquitin-mediated degradation of Sic1, an event triggered by Cln1, 2-Cdc28 mediated phosphorylation. We recently showed that Sic1 is involved in carbon source modulation of the critical cell size required to enter S phase. Here we show that the amount and sub-cellular localization of Sic1 are also carbon source-modulated. We identify a bipartite nuclear localization sequence responsible for nuclear localization of Sic1 and for correct cell cycle progression in a carbon-source dependent manner. Similarly to Cip/Kip proteins-Sic1 mammalian counterparts-Sic1 facilitates nuclear accumulation of its cognate cyclin, since cytoplasmic building-up of Clb5 is observed upon switching off expression of the SIC1 gene. Our data indicate a previously unrecognized inhibitor/activator dual role for Sic1 and put it among key molecules whose activity is regulated by their nuclear-cytoplasmic localization.

Active Transport, Cell Nucleus↗
PubMed2004

Nrg1 and nrg2 transcriptional repressors are differently regulated in response to carbon source.

The Nrg1 and Nrg2 repressors of Saccharomyces cerevisiae have highly similar zinc fingers and closely related functions in the regulation of glucose-repressed genes. We show that NRG1 and NRG2 are differently regulated in response to carbon source at both the RNA and protein levels. Expression of NRG1 RNA is glucose repressed, whereas NRG2 RNA levels are nearly constant. Nrg1 protein levels are elevated in response to glucose limitation or growth in nonfermentable carbon sources, whereas Nrg2 levels are diminished. Chromatin immunoprecipitation assays showed that Nrg1 and Nrg2 bind DNA both in the presence and absence of glucose. In mutant cells lacking the corepressor Ssn6(Cyc8)-Tup1, promoter-bound Nrg1, but not Nrg2, functions as an activator in a reporter assay, providing evidence that the two Nrg proteins have distinct properties. We suggest that the differences in expression and function of these two repressors, in combination with their similar DNA-binding domains, contribute to the complex regulation of the large set of glucose-repressed genes.

Chromatin↗
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↗
PubMed1993

Use of an Exotic Carbon Source To Selectively Increase Metabolic Activity and Growth of Pseudomonas putida in Soil.

Respiration and growth of Pseudomonas putida PpG7, containing catabolic plasmid NAH7, was determined in three agricultural field soils amended with the carbon source salicylate. The addition of salicylate to soil significantly increased the population of PpG7. However, there was a lack of relationship between microbial numbers and activity as determined by evolution of CO(2). In soils containing 30 to 1,500 mug of salicylate per g, metabolic activities of PpG7 peaked between 18 and 42 h and population densities increased approximately 10-to 10-fold. However, the metabolic activity of PpG7 rapidly declined after salicylate was utilized, whereas peak population densities were maintained for the duration of the experiments (5 to 7 days). Thus, elevated population densities of PpG7 were represented by inactive cells. Soil type had only minor effects on respiration rates or growth curves of PpG7 when amended with comparable concentrations of salicylate. Respiration and growth rates were optimal at concentrations between 300 and 1,000 mug of salicylate per g in the test soils. At 1,500 to 2,500 mug/g, respiration and growth of PpG7 were initially suppressed, but after a short lag time both attained levels similar to or greater than those resulting from the use of lower concentrations of salicylate. The culturing of PpG7 on a salicylate-amended medium to induce salicylate-degradative enzymes did not affect the lag time before utilization of salicylate in soil. Although PpG7 competed well with fungi for the substrate, suppression of fungal populations with cycloheximide resulted in significantly increased population densities of PpG7 in two of three soils amended with salicylate. The beneficial activities of bacteria in soil are discussed in relation to population density, population metabolic activity, and selective carbon source utilization.

Journal Article↗
PubMed2003

The Escherichia coli BarA-UvrY two-component system is needed for efficient switching between glycolytic and gluconeogenic carbon sources.

The Escherichia coli BarA and UvrY proteins were recently demonstrated to constitute a novel two-component system, although its function has remained largely elusive. Here we show that mutations in the sensor kinase gene, barA, or the response regulator gene, uvrY, in uropathogenic E. coli drastically affect survival in long-term competition cultures. Using media with gluconeogenic carbon sources, the mutants have a clear growth advantage when competing with the wild type, but using media with carbon sources feeding into the glycolysis leads to a clear growth advantage for the wild type. Results from competitions with mutants in the carbon storage regulation system, CsrA/B, known to be a master switch between glycolysis and gluconeogenesis, led us to propose that the BarA-UvrY two-component system controls the Csr system. Taking these results together, we propose the BarA-UvrY two-component system is crucial for efficient adaptation between different metabolic pathways, an essential function for adaptation to a new environment.

Bacterial Proteins↗
PubMed1980

Effects of carbon source and growth rate on cell wall composition of Bacillus subtilis subsp. niger.

A study was made to determine whether factors other than the availability of phosphorus were involved in the regulation of synthesis of teichoic and teichuronic acids in Bacillus subtilis subsp. niger WM. First, the nature of the carbon source was varied while the dilution rate was maintained at about 0.3 h-1. Irrespective of whether the carbon source was glucose, glycerol, galactose, or malate, teichoic acid was the main anionic wall polymer whenever phosphorus was present in excess of the growth requirement, and teichuronic acid predominated in the walls of phosphate-limited cells. The effect of growth rate was studied by varying the dilution rate. However, only under phosphate limitation did the wall composition change with the growth rate: walls prepared from cells grown at dilution rates above 0.5 h-1 contained teichoic as well as teichuronic acid, despite the culture still being phosphate limited. The wall content of the cells did not vary with the nature of the growth limitation, but a correlation was observed between the growth rate and wall content. No indications were obtained that the composition of the peptidoglycan of B. subtilis subsp. niger WM was phenotypically variable.

Bacillus subtilis↗
PubMed1981

Effect of carbon source on growth rate and phospholipid composition of Escherichia coli 15T- and an unsaturated fatty acid auxotroph.

Escherichia coli 15T- was grown with glucose, succinic acid, aspartic acid, oleic acid, and oleic plus aspartic acids as carbon sources, and a fatty acid auxotroph derived from 15T- was grown on oleic acid and oleic plus aspartic acids. The doubling time, phospholipid composition, phosphorus content, and the fatty acid composition of the phospholipids of cells in each of the media were determined. In all cases, phosphatidylethanolamine was the major phospholipid present; but with 15T- its concentration was inversely proportional to the doubling time in unsupplemented media. With the auxotroph the phosphatidylethanolamine concentration was essentially unchanged with growth. Total lipid phosphorus was inversely proportional to doubling time, an effect particularly evident with the auxotroph. Without oleic acid supplementation, the major effects of carbon source on fatty acid composition are decreases in the content of palmitoleic acid and increases in the content of cis-9, 10-methylene hexadecanoic acid as growth rate decreases. Oleic acid supplementation elevated 18:1 fatty acid content in both 15T- and the auxotroph.

Aspartic Acid↗
PubMed2002

Acidogenic fermentation: utilization of wasted sludge as a carbon source in the denitrification process.

Laboratory scale batch experiments were conducted at 20 degrees C to investigate the acidogenic fermentation for the conversion of wasted sludge into short chain fatty acids (SCFA) to be utilized as a carbon source in the denitrification process. Hydraulic retention time (HRT), volatile solid (VS) loading rate and pH were studied as these are the important parameters governing the production of volatile fatty acids (VFA). Four different phases were investigated by varying these parameters. HRT was varied from 2.7 to 8.2 days whereas VS loading rate was varied from 1.2 to 3.6 g d(-1). VFA production decreased with the increase in HRT above 2.7 days. 538.37+/-19.39 mg VFA(produced) x d(-1) (0.176+/-0.010 mg VFA(produced) mg(-1) VS(feed) was found as the maximum value of VFA at 2.7 days. The present results based on wasted sludge showed that almost 0.0483+/-0.0016 mg VFA (as COD mg(-1) initial COD) and about 5% of soluble COD production were achieved, which are slightly less than the results reported for primary sludges. The rates of VFA production increased with the increase in VS, however, opposite results were obtained when pH was increased in the reactor. SCFA/FA ratios during fermentation were found in the range of 67-73%. The specific denitrification rates (SDNR) of methanol (2.20+/-0.44 mg NO3-N g(-1) MLVSS x h(-1)) and the fermenter supernatant (2.00+/-0.45 mg NO3-N g(-1) MLVSS x h(-1)) were found to be comparable. Fermenter supernatant, therefore, has the potential to be utilized as a carbon source. However, the results need to be investigated further on a larger scale to ascertain their validity.

Biodegradation, Environmental↗
PubMed2000

Aca1 and Aca2, ATF/CREB activators in Saccharomyces cerevisiae, are important for carbon source utilization but not the response to stress.

In Saccharomyces cerevisiae, the family of ATF/CREB transcriptional regulators consists of a repressor, Acr1 (Sko1), and two activators, Aca1 and Aca2. The AP-1 factor Gen4 does not activate transcription through ATF/CREB sites in vivo even though it binds these sites in vitro. Unlike ATF/CREB activators in other species, Aca1- and Aca2-dependent transcription is not affected by protein kinase A or by stress, and Aca1 and Aca2 are not required for Hog1-dependent salt induction of transcription through an optimal ATF/CREB site. Aca2 is important for a variety of biological functions including growth on nonoptimal carbon sources, and Aca2-dependent activation is modestly regulated by carbon source. Strains lacking Aca1 are phenotypically normal, but overexpression of Aca1 suppresses some defects associated with the loss of Aca2, indicating a functional overlap between Aca1 and Aca2. Acr1 represses transcription both by recruiting the Cyc8-Tup1 corepressor and by directly competing with Aca1 and Aca2 for target sites. Acr1 does not fully account for osmotic regulation through ATF/CREB sites, and a novel Hog1-dependent activator(s) that is not a bZIP protein is required for ATF/CREB site activation in response to high salt. In addition, Acr1 does not affect a number of phenotypes that arise from loss of Aca2. Thus, members of the S. cerevisiae ATF/CREB family have overlapping, but distinct, biological functions and target genes.

Activating Transcription Factors↗
PubMed1994

[Optimal structure of the multienzyme system of the tricarboxylic acid cycle of E. coli during growth on various carbon sources].

The optimal structure (stoichiometry) of the tricarboxylic acid cycle multienzyme system of E. coli has been computed using experimental data for the E. coli biomass monomeric content and the results of the steady-state metabolic fluxes calculation. The calculation was performed for the cases of E. coli growth on acetate, glycolate, glycerate, glutamate, glucose, gluconate and pyruvate as carbon sources. The possible self-control mechanisms make it possible to optimize the cellular multienzyme system structure for each of the carbon sources under study. The relationship between the optimal structure and the maximal specific rate of the cell growth is discussed.

Carbon↗
PubMed2000

Effect of the carbon source on assessment of degrading bacteria with the spread-plating technique during in situ bioremediation.

Spread-plating belongs to traditional microbiological methods employed for quantification of subsurface microflora during bioremediation projects in the Czechia. Concentration of degrading organisms is estimated from the number of colonies grown on agar plates supplied with contaminant as the sole carbon source. The data obtained during in situ bioremediation of the Dacice site contaminated by cutting oil suggests that changes in the composition of the carbon source in the subsurface may cause a discrepancy between laboratory data and situation in subsurface.

Bacteria↗
PubMed2004

Short-term effects of carbon source on the competition of polyphosphate accumulating organisms and glycogen accumulating organisms.

The effectiveness of enhanced biological phosphorus removal (EBPR) systems is directly affected by the competition of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). This study investigated the short-term effects of carbon source on PAO and GAO performance. The tests were designed to clearly determine the impact of volatile fatty acid (VFA) composition on the performance of two types of biomass, one enriched for PAOs and the other for GAOs. The two populations were enriched in separate reactors using identical operating conditions and very similar influent compositions with acetate as the sole carbon source. The only difference was that a very low level of phosphorus was present in the influent to the GAO reactor. The abundance of PAOs and GAOs was quantified using fluorescence in-situ hybridisation. The results clearly show that there are some very distinctive differences between PAOs and GAOs in their ability to utilise different carbon substrates. While both are able to take up acetate rapidly and completely, the GAOs are far slower at consuming propionate than the PAOs during short-term substrate changes. This provides a potentially highly valuable avenue to influence the competition between PAOs and GAOs. Other VFAs studied seem to be less usable in the short term by both PAOs and GAOs, as indicated by their much lower uptake rates.

Bacteria, Anaerobic↗
PubMed2005

Carbon source dependent somatic embryogenesis and plant regeneration in cotton, Gossypium hirsutum L. cv. SVPR2 through suspension cultures.

Highly reproducible and simple protocol for cotton somatic embryogenesis is described here by using different concentrations of maltose, glucose, sucrose and fructose. Maltose (30 g/l) is the best carbon source for embryogenic callus induction and glucose (30 g/l) was suitable for induction, maturation of embryoids and plant regeneration. Creamy white embryogenic calli of hypocotyl explants were formed on medium containing MS basal salts, myo-inositol (100 mg/l), thiamine HCI (0.3 mg/l), picloram (0.3 mg/l), Kin (0.1 mg/l) and maltose (30 g/l). During embryo induction and maturation, accelerated growth was observed in liquid medium containing NH3NO4 (1 g/l), picloram (2.0 mg/l), 2 ip (0.2 mg/l), Kin (0.1 mg/l) and glucose (30 g/l). Before embryoid induction, large clumps of embryogenic tissue were formed. These tissues only produced viable embryoids. Completely matured somatic embryos were germinated successfully on the medium fortified with MS salts, myo-inositol (50 mg/l), thiamine HCl (0.2 mg/l), GA3 (0.2 mg/l), BA (1.0 mg/l) and glucose (30 g/l). Compared with earlier reports, 65% of somatic embryo germination was observed. The abnormal embryo formation was highly reduced by using glucose (30 g/l) compared to other carbon sources. The regenerated plantlets were fertile but smaller in height than the seed derived control plants.

Carbon↗
PubMed1999

A strong carbon source effect is mediated by pUC plasmid sequences in a series of classical yeast vectors designed for promoter characterization.

While using YIp356 and YEp356R lacZ reporter plasmids, we found lacZ expression driven by the ARG2 promoter to be much higher in cells grown on a non-glucose carbon source than in glucose-grown cells (5-10-fold higher on galactose and up to 40-fold higher on ethanol). Furthermore, expression increased 30-fold upon shifting from a high-glucose to a low-glucose medium. This carbon source regulation requires Snf1p and possibly Ssn6p. It appears, however, to be artefactually mediated by plasmid sequences located upstream from the multicloning site. This emerged from the following observations: (a) the derepressive effect disappears if any extra piece of DNA is inserted upstream from the ARG2 promoter; and (b) similar derepression on low glucose is observed with another yeast promoter (ARG11), provided that the flanking 5' region is short. We determined that the cis-elements responsible for this physiologically irrelevant glucose regulation are located between positions 636 and 879 of the pUC18 DNA sequence.

Artifacts↗
PubMed2002

Effect of different carbon sources and cold shock on protein synthesis by a psychrotrophic Acinetobacter sp.

The induction of proteins after a 25 to 5 degrees C cold shock in the psychrotrophic Acinetobacter HH1-l was examined using two-dimensional polyacrylamide gel electrophoresis. In addition, effects of various carbon sources (acetate, Tween 80, and olive oil) on protein synthesis after cold shock were assessed. HH1-1 responded to cold shock by synthesizing both cold shock proteins (csps) and cold acclimation proteins (caps). The synthesis of two csps (89 and 18) was increased 2 h after cold shock by the cells, regardless of the carbon source provided. An additional csp (csp 12), with an estimated molecular mass of 12 kDa, was observed in cells grown in olive oil only. Csp 12 was also synthesized when cells were incubated at 30 degrees C, suggesting that this protein may serve as a general stress protein. In addition to csps, caps were observed post cold shock at 72 h in acetate-grown cells and at 140 h in cells grown in Tween 80 and olive oil. Induction of cold-acclimated periplasmic proteins was observed for cells grown in olive oil only, suggesting cells grown in olive oil may be stressed by low temperatures to a greater extent than cells grown in either acetate or Tween 80.

Acetates↗