Principal Carbon Source Research Articles

Combustion as the Principal Source of Carbonaceous Aerosol in the Ohio River Valley

Organic and elemental carbon and a number of carboxylic acids and n-alkanes were measured in aerosol samples collected at three sites in the Ohio River Valley between October 1980 and August 1981. Approximately 100 filters were analyzed for organic and elemental carbon for each site. For the 11-month period organic and elemental carbon comprised about 19 percent of the total aerosol mass with about two-thirds of the carbon as organic. Regression analysis showed that the principal source of organic carbon was combustion. The measurements of the specific organic compounds indicated a weak biogenic component to the organic aerosol.

Biochemical changes during valine production by Aerobacter aerogenes.

The typical chemical changes taking place during valine production by A. aerogenes in a synthetic medium have been investigated. The principal carbon and nitrogen sources, sucrose and urea, respectively, have been found to be almost exhausted during an incubation period lasting 90 h. While the carbon compound was depleted right from the start of formentation, the disappearance of urea was noticeable after 16 h of incubation. The formation of valine in the broth started between 24 and 40 h of incubation connected with the rapid utilization of urea. The pH value of the broth was found to glide down from an initial value of 7.5 to 6.4 within 24 h then rising again to 7.5 during 64 h and further to 8.0 in 90 h of incubation.

Effects of various carbon and nitrogen sources on fungal lipid production

AbstractThe efficiency of lipid production byTolyposporium ehrenbergii andSpacelotheca reiliana (family Ustilaginaceae) cultivated on a fat‐free medium was evaluated. The fungi were artificially cultured on media containing various monoor disaccharides and urea or peptone as basic sources for carbon and nitrogen, respectively. Some natural and industrial byproducts (glycerol, glucose syrup, potato hydrolysate and molasses hydrolysate) were also used as principal carbon sources for fungal growth. Media containing fructose/peptone or glucose/peptone were the most efficient for fungal fat production during one week of incubation. After a two‐week incubation period, highest phospholipid concentrations were found in S.reiliana andT. ehrenbergii mycelia obtained from media containing molasses hydrolysate/peptone and glycerol/urea, respectively. Fatty acid analysis of the fungal growth indicated the presence of a wide range of fatty acids, i.e., odd‐and even‐carbon numbered acids, both saturated and unsaturated. The results demon‐strated that the variability in the fatty acid composition largely depends on the type of sugar and nitrogen sources and the age of the culture.

Glycerol and myo-inositol as carbon sources for the induction of xylogenesis in explants of Lactuca

Glycerol (2% w/v) and myo-inositol (2% w/v), respectively, functioned as the principal exogenous carbon source for the induction of tracheary element differentiation in cultured expiants of lettuce pith (Lactuca sativa cv. Romána). Although tracheary elements were first observed after 3 days on a xylogenic medium supplemented with either glucose (2% w/v) or myo-inositol (2% w/v), the induction of xylogenesis in explants cultured on a similar medium containing glycerol (2% w/v) required a minimum of 6 days. Tracheary elements formed in the presence of glycerol and myo-inositol, respectively, were characterized by various patterns of scalariform-reticulate secondary wall thickenings which were indistinguishable from tracheary elements produced under similar cultural conditions in the presence of glucose as the principal carbon source. This is the first report of a major exogenous carbon source other than a carbohydrate supporting the cytodifferentiation of tracheary elements under in vitro conditions.

Dietary carbon sources of mussels and tubeworms from Galápagos hydrothermal vents determined from tissue 14C activity

The large quantities of reduced carbon that are required to support the filter-feeding mytilid mussels (Mytilus sp.), vesi-comyid clams (Calyptogena sp.) and various other animals in the Galapagos hydrothermal vent systems are thought to be derived from either the in situ synthesis of particulate organic matter by chemoautotrophic, sulphide-oxidizing bacteria1,2 or by the advection of sedimentary organic carbon into the vent environment from surrounding areas3,4. In contrast, the dense populations of vestimentiferan tubeworms (Riftia pachyptila), which lack mouth organs and digestive tracts, apparently utilize organic carbon synthesized by symbiotic chemoautotrophs5. We present evidence here, based on 14C activities and 13C/12C ratios, that the principal source of dietary carbon for mussels and tubeworms is derived from the dissolved inorganic carbon (DIOC) in the vent effluent waters.

Streptomyces setonii: catabolism of vanillic acid via guaiacol and catechol.

Streptomyces setonii (strain 75Vi2) was grown at 45 degrees C in liquid media containing simple aromatic compounds as principal carbon sources. Thin-layer chromatography, UV spectrophotometry, and gas chromatography were used to show that S. setonii converted benzoic acid, guaiacol, and vanillic acid to catechol; p-hydroxybenzoic acid to protocatechuic acid; and m-hydroxybenzoic acid to gentisic acid. Presence of the ring-cleavage enzymes catechol 1,2-dioxygenase, protocatechuate 3,4-dioxygenase, and gentisate 2,3-dioxygenase was shown both by O2 uptake in ring-cleavage reactions catalyzed by cell-free extracts and by changes in UV spectra that indicated the presence of specific ring-cleavage products. A unique feature of this strain was its catabolism of vanillic acid by of guaiacol and catechol, using a pathway that had not been confirmed previously.

Isolation of two lipoamide dehydrogenases from [formula omitted] grown on valine

Pseudomonas putida PPG2 grown on valine as the principal carbon and energy source produces two species of lipoamide dehydrogenase, molecular weights 56k and 49k. Pseudomonas putida grown on glucose as the carbon source produces only the 56k lipoamide dehydrogenase. The 56k proteins from P. putida grown on glucose and valine were not separated by SDS-Page and may be the same proteins. Pyruvate dehydrogenase of mutant JS94 lacking lipoamide dehydrogenase was restored by the 56k protein but not by the 49k protein. Branched chain keto acid dehydrogenase was partially restored by the 49k protein, but not the 56k protein.

Catabolism of Substituted Benzoic Acids by Streptomyces Species

Four thermotolerant actinomycetes from soil, identified as Streptomyces albulus 321, Streptomyces sioyaensis P5, Streptomyces viridosporus T7A, and Streptomyces sp. V7, were grown at 45 degrees C in media containing either benzoic acid or hydroxyl- and methoxyl-substituted benzoic acids as the principal carbon sources. Benzoic acid was converted to catechol; p-hydroxybenzoic, vanillic, and veratric acids were converted to protocatechuic acid; and m-hydroxybenzoic acid was converted to gentisic acid. Catechol, protocatechuic acid, and gentisic acid were cleaved by catechol 1,2-dioxygenase, protocatechuate 3,4-dioxygenase, and gentisate 1,2-dioxygenase, respectively. Dioxygenases appeared only in induced cultures. m-Hydroxybenzoic, m-anisic, and p-anisic acids were gratuitous inducers of dioxygenases in some strains. One strain converted vanillic acid to guaiacol.

Simultaneous production of cellulase complex and glucose isomerase by Streptomyces flavogriseus

Fermentations of Streptomyces flavogriseus were carried out at 30° C on media containing either Avicel, hay or acid hay hydrolysate as the principal carbon source. Under these conditions the strains produced simultaneously the enzymes of the cellulase complex as well as glucose isomerase. The enzyme activities were induced by hay, hay extract and D-xylose.

The carbon isotope geochemistry of a small groundwater system in northeastern Ontario

The carbon isotopic composition (13C and 14C) of the inorganic carbon dissolved in the waters of a small, largely unconfined aquifer in unconsolidated sediments on the Canadian Shield has been investigated. Three principal carbon sources are recognized: soil CO2, rock carbonate, and biogenic CO2. The average δ13C value of the soil CO2 is close to −21.0 ± 1.5%, and present‐day 14C activities of the soil CO2 vary between 130 and 162% modern 14C. Very minor amounts (< 1.0%) of carbonate minerals (δ13C = −0.6‰) are present within the aquifer and react with this soil CO2 to produce a dissolved inorganic carbon (DIC) with 14C activities which are as much as 50% below the initial activities of the soil CO2. The third carbon source, a biogenic CO2, could be detected only indirectly, and its presence is primarily deduced from the occurrence of methane in the deeper parts of these aquifers. The large isotope fractionation which occurs during bacterial coproduction of CO2 with this methane results, however, in a 13C‐rich CO2 and thus a DIC with high δ13C values. Values of δ13C as high as +11‰ have been measured in groundwaters on the Canadian Shield. Since the origin of the destroyed organic matter is not yet known, no assessment of the importance of this CO2 for the 14C contents of the DIC is possible.

Genetic regulation of galactokinase in Tetrahymena by cyclic AMP, glucose, and epinephrine

We have found evidence that transcription of the galactokinase (ATP:D-galactose 1-phosphotransferase; EC 2.7.1.6) gene is inhibited, in the animal-like protozoan Tetrahymena, by dibutyryl adenosine 3':5'-cyclic monophosphate, glucose, and epinephrine. The specific activities of galactokinase in Tetrahymena cells grown in defined media with galactose or glycerol as the principal carbon source are equivalent; the specific activity in glucose minimal medium is [unk] the value. Thus, while there seems to be no specific induction of the enzyme by the substrate, galactose, there is a strong "repression" by glucose. This repression by glucose is mimicked, in glycerol-grown cells, by the addition of millimolar amounts of dibutyryl adenosine 3':5'-cyclic monophosphate or phosphodiesterase inhibitors such as caffeine and theophylline. When glucose-grown cells are washed and resuspended in carbohydrate-free medium, the galactokinase specific activity increases by as much as 10-fold within 12 hr. This increase is blocked by dibutyryl adenosine 3':5'-cyclic monophosphate and by epinephrine (synthesized by Tetrahymena, and previously shown to activate a membrane-bound adenylate cyclase in extracts of this organism), as well as by inhibitors of mRNA synthesis, maturation, and translation. Our results suggest that glucose and epinephrine can regulate transcription of the galactokinase gene by modulation of cyclic nucleotide levels. The observation that the nonmetabolized sugars 2-deoxyglucose, 2-deoxygalactose, and alpha-methylglucoside are as effective as glucose suggests that the sugar itself, or an immediate metabolite such as the 1-phosphate derivative, may be the effector.

Turnover as a control of ribonucleic acid accumulation in bacteria undergoing stepdown.

The synthesis of ribosomes was compared in rel+ and rel- strains of Escherichia coli undergoing "stepdown" in growth from glucose medium to one with lactate as principal carbon source. Two strains (CP78 and CP79), isogenic except for rel, showed similar behaviour with respect to (1) the kinetics of labelling total RNA and ribosomes with exogenous uracil, (2) the proportion of newly formed protein that could be bound with nascent rRNA in mature ribosomes, and (3) the rate of induction of enzymically active beta-galactosidase (relative to the rate of ribosome synthesis). It was concluded that, as there was no net accumulation of RNA during stepdown in either strain, rRNA turnover must be occurring at a high rate. The general features of ribosome maturation in rel+ and rel- cells were almost identical with those found in auxotrophic rel+ organisms starved of required amino acids. In both cases, there was a considerable delay in the maturation of new ribosomal particles, owing to a relative shortfall in the rate of synthesis of ribosome-associated proteins. Only about 4-5% of the total protein labelled during stepdown was capable of binding with newly formed rRNA. This compared with 3.5% for rel+ and 0.5% for rel- auxotrophs during amino acid starvation. The turnover rate for newly formed mRNA and rRNA was virtually the same in "stepped-down" rel+ and rel- strains and was similar to that of the same fraction in amino acid-starved rel+ cells. The functional lifetime of mRNA was also identical. It seems that in the rel- strain many of the characteristics typical of the isogenic rel+ strain are displayed under these conditions, at least as regards the speed of ribosome maturation and the induction of beta-galactosidase. Studies on the thermolability of the latter enzyme induced during stepdown indicate that inaccurate translation, which occurs in rel- strains starved for only a few amino acids, is less evident in this situation than in straightforward amino acid deprivation.

Metabolism of the germinating sclerotium of Claviceps purpurea.

The concentration of free amino acids, particularly alanine, altered as stromata developed on germinating sclerotia. Lipid reserves in the sclerotium provided the principal carbon and energy source, and the nutrients required for stomatal growth appeared to be provided by the sclerotial tissues immediately beneath the point of attachment of the stoma. Alkaloid did not disappear from the sclerotia during germination. Very high levels of polyol, particularly mannitol, were attained in the stromata as germination progressed; the synthesis of polyol was usually accompanied by that of soluble sugars, notably glucose. In an attempt to ascertain the role of mannitol in germination, the relationship between polyol and soluble sugars was investigated in excised stromata after their submergence in buffered media containing a variety of soluble carbohydrates. Mannitol was synthesized under these conditions by way of phosphorylated intermediates, and chiefly in the capitulum, after rapid, and probably passive, absorption of the exogenously supplied sugar. The tissues equilibrated rapidly with the supplied carbohydrate, whose concentration was maintained by further uptake whilst mannitol was being synthesized. The concentrations of assimilated glucose and synthesized mannitol tended toward the same value during incubation and the results suggested that the synthesis was compartmentalized within the stromata. Very little exogenously supplied mannitol was assimilated.

Control of the synthesis of a single enzyme by multiple regulatory circuits in Neurospora crassa.

Neurospora crassa synthesizes and secretes an extracellular protease into its growth medium when an exogenous protein serves as its principal source of sulfur, nitrogen, or carbon. The enzymes produced under these three growth conditions have been compared by a number of criteria. The results indicate that the same extracellular protease with a molecular weight of 31,000 is synthesized during the three different metabolic conditions. A regulatory mutant, which lacks a positive signal required for the synthesis of a family of related enzymes for sulfur metabolism, cannot synthesize the protease in response to a limitation for sulfur; yet, this same mutant is capable of producing the enzyme when it is limited for either nitrogen or carbon. A second regulatory mutant, defective in the control of nitrogen metabolism, fails to synthesize the protease only when it is limited for nitrogen. The evidence suggests that a single structural gene for this extracellular protease exists and that it is regulated in a complex fashion such that control signals arising from any one of the three distinct regulatory circuits can activate it for expression. A model is proposed for complex regulation of the synthesis of this enzyme.

Mise en �vidence et propri�t�s de deux formes de la 5-d�shydroquinate hydro-lyase chez les v�g�taux sup�rieurs

Two dehydroquinate hydro-lyases (E.C. 4.2.1.10) have been routinely separated from different organs of Zea mays L. by chromatography on Cellex-D Bio-Rad or hydroxypatite using linear salt gradients. Dehydroquinate hydro-lyase 1 is associated with shikimate: NADP+ oxidoreductase (E.C. 1.1.1.25). DHQase 2 is a free constitutive enzyme; in this respect it differs from the inducible enzyme of microorganisms which appears only when dehydroquinate or quinate is the principal carbon source. DHQase 1 and DHQase 2 have a similar apparent Michaelis constant and pH optimum, but they differ in their molecular weight, thermal stability and sensitivity to metabolic effectors. DHQase 2 is specifically activated by shikimic acid. This strong activation and the channeling properties of the complex involved in the shikimate pathway can provide an effective means of control in the utilization of dehydroquinate between two different pathways. The significance of such a system involving both a specific regulation of isoenzymes and a molecular compartmentation by means of an enzymatic complex is discussed.

Selection and characterization of acriflavine-induced mutants of Candida albicans.

Acriflavine-treated cells of C. albicans plated on a medium containing glucose as the principal carbon source gave rise to numerous colonies, most of which grew when replica-plated onto a similar medium containing sodium acetate substituted for glucose. Of the small fraction of colonies from the glucose medium which failed to replicate, some were found to be true petites, deficient for cytochromes a and b; others possessed complete cytochrome spectra, like those of their wild-type parents, but, nevertheless, respired at reduced rates on both fermentable and non-fermentable substrates. The role of the conventional cytochrome system in a wild-type culture was indicated by the strong inhibition of its respiration by cyanide, azide and antimycin A.

Biosynthesis of Lycomarasmin

Cultures of Fusarium oxysporum Schl. emend. Sny. et Hans. f lycopersici (Sacc.) Sny. et Hans. grown on a liquid medium with glucose as the principal carbon source produce, among other products, the phytotoxin lycomarasmin. Acid hydrolysis of lycomarasmin results in the formation of aspartic acid, glycine, and pyruvic acid. Tracer studies showed that glycine-U-I4C, L-serine-U-14C, DL-aspartic acid-4-14C, DL-alanine-1-14C, and glucose-U-14C served as relatively efficient precursors of the lycomarasmin molecule. DL-Aspartic acid-4-I4C was incorporated into the 4-carbon fragment without label scrambling. Glycine was found to be the most efficient precursor of the 2-carbon fragment while glucose afforded the most efficient and direct route for the 3-carbon fragment.

Regulation of exocellular proteases in Neurospora crassa: role of Neurospora proteases in induction.

Cells of Neurospora crassa strain 74A, grown on sucrose for 12 h and transferred to a medium containing protein as sole carbon source, would not produce exocellular protease in significant amounts. When a filtrate from a culture induced to make protease by normal growth on a medium containing protein as principal carbon source was added to an exponential-phase culture in protein medium, exocellular protease was made in amounts similar to those made during normal induction. The material in the culture filtrate that participated in the induction process was identified as protease by its heat lability, molecular weight, and the dependence of induction rate on units of proteolytic activity added to the exponential-phase culture. Induction of the formation of exocellular protease by exponential-phase cells appears to require a protein substrate, added proteolytic activity, and protein synthesis. The protease produced by induced exponential-phase cells was as efficient in promoting induction as normally induced enzyme, whereas constitutive intracellular enzyme was only 50% as efficient. The bacterial protease thermolysin was able to induce exocellular protease at 90.7% of the rate observed with added N. crassa exocellular protease.

Hispidin biosynthesis in cultures of Polyporus hispidus

Cultures of Polyporus hispidus grown on a liquid medium with glucose as the principal carbon source produced the yellow pigment hispidin (4-hydroxy-6-(3,4-dihydroxystyryl)-2-pyrone) (II). Tracer studies showed that DL-phenylalanine, DL-tyrosine, cinnamate, p-coumarate and caffeate were incorporated into the hispidin molecule without scrambling of the label. Good incorporation of acetate and roalonate into the pyrone portion of the molecule was observed. The related styrylpyrone, bis-noryangonin (4-hydroxy-6-(4-hydroxystyryl)-2-pyrone) (1) was also detected in extracts of cultured mycelium and a cell-free enzyme preparation was obtained which catalyzed the hydroxylation of bis-noryangonin to hispidin.

Metabolism of aromatic acids by Polyporus hispidus

When grown on glucose as principal carbon source the culture medium of Polyporus hispidus was found to contain phenolic acids, including p-coumaric and caffeic acids. 14C-Studies indicated that phenylalanine is converted to cinnamic acid as well as to phenylpyruvic acid and tyrosine in cultures. Cell-free preparations of mycelium contained phenylalanine and tyrosine ammonia-lyse activities and were capable of effecting the hydroxylation of cinnamic, p-coumaric and benzoic acids.