Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:7440-44-0 (Carbon)
 10,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carbon and nitrogen regulation of UBI4, the stress-inducible polyubiquitin gene of Saccharomyces cerevisiae, was investigated using a UBI4 promoter-LacZ fusion gene (UBI4-LacZ). Expression of this gene in cells grown on different media indicated that the UBI4 promoter is more active during growth on respiratory than on fermentable carbon sources but is not subject to appreciable control by nitrogen catabolite repression. UBI4-LacZ expression was virtually identical in cells having constitutively high (ras2, sra1-13) or constitutively low (ras2) levels of cyclic AMP-dependent protein kinase activity, indicating that this kinase does not exert a major influence on UBI4 expression. Catabolite derepression control of the UBI4 promoter was confirmed by measurements of UBI4-LacZ expression in hap mutant and wild-type strains before and after transfer from glucose to lactate. Mutagenesis of the perfect consensus for HAP2/3/4 complex binding at position -542 resulted in considerable reduction of UBI4 promoter derepression with respiratory adaptation in HAP wild-type cells and abolished the reduced UBI4-LacZ derepression normally seen when aerobic cultures of the hap1 mutant are transferred from glucose to lactate. This HAP2/3/4 binding site is therefore a major element contributing to catabolite derepression of the UBI4 promoter, although data obtained with hapl mutant cells indicated that HAP1 also contributes to this derepression. The HAP2/3/4 and HAP1 systems are normally found to activate genes for mitochondrial (respiratory) functions. Their involvement in mediating higher activity of the UBI4 promoter during respiratory growth may reflect the contribution of UBI4 expression to tolerance of oxidative stress.
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PMID:UBI4, the polyubiquitin gene of Saccharomyces cerevisiae, is a heat shock gene that is also subject to catabolite derepression control. 903 3

Enrichment cultures were prepared under strictly anoxic conditions in medium representing fresh water and containing an organosulfonate as electron donor and carbon source, and nitrate as electron acceptor. The inoculum was from the anaerobic digestor of two communal sewage works. The natural organosulfonates 2-aminoethanesulfonate (taurine), DL-2-amino-3-sulfopropionate (cysteate) and 2-hydroxyethanesulfonate (isethionate) all gave positive enrichments, whereas unsubstituted alkanesulfonates, such as methanesulfonate and arenesulfonates, gave no enrichment. Two representative enrichments were used to obtain pure cultures, and strains NKNTAU (utilizing taurine) and NKNIS (utilizing isethionate) were isolated. Strain NKNTAU was examined in detail. Out of 18 tested organosulfonates, it utilized only one, taurine, and was identified as a novel Alcaligenes sp., a facultatively anaerobic bacterium. Carbon from taurine was converted to cell material and carbon dioxide. The amino group was released as ammonium ion and the sulfonate moiety was recovered as sulfate. Nitrate was reduced to nitrogen gas.
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PMID:Anaerobic taurine oxidation: a novel reaction by a nitrate-reducing Alcaligenes sp. 920 68

NNC 13-8241 has recently been labelled with iodine-123 and developed as a metabolically stable benzodiazepine receptor ligand for single-photon emission computed tomography (SPECT) in monkeys and man. NNC 13-8199 is a bromo-analogue of NNC 13-8241. This partial agonist binds selectively and with subnanomolar affinity to the benzodiazepine receptors. We prepared 76Br labelled NNC 13-8199 from the trimethyltin precursor by the chloramine-T method. Carbon-11 labelled NNC 13-8199 was synthesised by N-alkylation of the nitrogen of the amide group with [11C]methyl iodide. Positron emission tomography (PET) examination with the two radioligands in monkeys demonstrated a high uptake of radioactivity in the occipital, temporal and frontal cortex. In the study with [76Br]NNC 13-8199, the monkey brain uptake continued to increase until the time of displacement with flumazenil at 215 min after injection. For both radioligands the radioactivity in the cortical brain regions was markedly reduced after displacement with flumazenil. More than 98% of the radioactivity in monkey plasma represented unchanged radioligand 40 min after injection. The low degree of metabolism indicates that NNC 13-8199 is metabolically much more stable than hitherto developed PET radioligands for imaging of benzodiazepine receptors in the primate brain. [76Br]NNC 13-8199 has potential as a radioligand in human PET studies using models where a slow metabolism is an advantage.
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PMID:Bromine-76 and carbon-11 labelled NNC 13-8199, metabolically stable benzodiazepine receptor agonists as radioligands for positron emission tomography. 932 67

Early work on proteins identified the existence of helices and extended sheets in protein secondary structures, a high-level classification which remains popular today. Using the Snob program for information-theoretic Minimum Message Length (MML) classification, we are able to take the protein dihedral angles as determined by X-ray crystallography, and cluster sets of dihedral angles into groups. Previous work by Hunter and States has applied a similar Bayesian classification method, AutoClass, to protein data with site position represented by 3 Cartesian co-ordinates for each of the alpha-Carbon, beta-Carbon and Nitrogen, totalling 9 co-ordinates. By using the von Mises circular distribution in the Snob program, we are instead able to represent local site properties by the two dihedral angles, phi and psi. Since each site can be modelled as having 2 degrees of freedom, this orientation-invariant dihedral angle representation of the data is more compact than that of nine highly-correlated Cartesian co-ordinates. Using the information-theoretic message length concepts discussed in the paper, such a more concise model is more likely to represent the underlying generating process from which the data came. We report on the results of our classification, plotting the classes in (phi, psi) space; and introducing a symmetric information-theoretic distance measure to build a minimum spanning tree between the classes. We also give a transition matrix between the classes and note the existence of three classes in the region phi approximately -1.09 rad and psi approximately -0.75 rad which are close on the spanning tree and have high inter-transition probabilities. This gives rise to a tight, abundant and self-perpetuating structure.
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PMID:Circular clustering of protein dihedral angles by Minimum Message Length. 939 Feb 36

Pasture-grazed dairy cows, deer, and sheep were tested for the presence of ammonia-hyperproducing (HAP) bacteria in roll tubes containing a medium in which tryptone and Casamino Acids were the sole nitrogen and energy sources. Colonies able to grow on this medium represented 5.2, 1.3, and 11.6% of the total bacterial counts of dairy cows, deer, and sheep, respectively. A total of 14 morphologically distinct colonies were purified and studied further. Restriction fragment length polymorphisms of 16S rRNA genes indicated that all isolates differed from the previously described HAP bacteria, Clostridium aminophilum, Clostridium sticklandii, and Peptostreptococcus anaerobius. Carbon source utilization experiments showed that five isolates (C2, D1, D4, D5, and S1) were unable to use any, or very few, of the carbon sources tested. Biochemical tests and phylogenetic analyses of 16S ribosomal DNA sequences indicated that all isolates were monensin sensitive; that D1 and S1 belonged to the genus Peptostreptococcus, that D4 and D5 belonged to the family Bacteroidaceae, where D4 was similar to Fusobacterium necrophorum; and that C2 was most similar to an unidentified species from the genus Eubacterium. Growth on liquid medium containing tryptone and Casamino Acids as the sole nitrogen and energy source showed that D1, D4, and S1 grew rapidly (specific growth rates of 0.40, 0.35, and 0.29 h-1, respectively), while C2 and D5 were slow growers (0.25 and 0.10 h-1, respectively). Ammonia production rates were highest in D1 and D4, which produced 945.5 and 748.3 nmol/min per mg of protein, respectively. Tests of individual nitrogen sources indicated that D1 and D4 grew best on tryptone, S1 grew equally well on Casamino Acids or tryptone, and C2 and D5 grew poorly on all nitrogen sources. The intact proteins casein and gelatin did not support significant growth of any of the isolates. These isolates extend the diversity of known HAP rumen bacteria and indicate the presence of significant HAP bacterial populations in pasture-grazed New Zealand ruminants.
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PMID:Ammonia-hyperproducing bacteria from New Zealand ruminants. 957 53

Surgical implant finishing and sterilization procedures were investigated to determine surface characteristics of unalloyed titanium (Ti). All specimens initially were cleaned with phosphoric acid and divided into five groups for comparisons of different surface treatments (C = cleaned as above, no further treatment; CP = C and passivated in nitric acid; CPS = CP and dry-heat sterilized; CPSS = CPS and resterilized; CS = C and dry-heat sterilized). Auger (AES), X-ray photoelectron (XPS), and Raman spectroscopic methods were used to examine surface compositions. The surface oxides formed by all treatments primarily were TiO2, with some Ti2O3 and possibly TiO. Significant concentrations of carbonaceous substances also were observed. The cleaning procedure alone resulted in residual phosphorus, primarily as phosphate groups along with some hydrogen phosphates. A higher percentage of physisorbed water appeared to be associated with the phosphorus. Passivation (with HNO3) alone removed phosphorus from the surface; specimens sterilized without prior passivation showed the thickest oxide and phosphorus profiles, suggesting that passivation alters the oxide characteristics either directly by altering the oxide structure or indirectly by removing moieties that alter the oxide. Raman spectroscopy showed no crystalline order in the oxide. Carbon, oxygen, phosphorus, and nitrogen presence were found to correlate with previously determined surface energy.
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PMID:Effect of surface treatment on unalloyed titanium implants: spectroscopic analyses. 959 42

The contribution of the biochemical pathways nitrification, denitrification, and dissimilatory NO3- reduction to NH4+ (DNRA) to the accumulation of NO2- in freshwaters is governed by the species compositions of the bacterial populations resident in the sediments, available carbon (C) and nitrogen (N) substrates, and environmental conditions. Recent studies of major rivers in Northern Ireland have shown that high NO2- concentrations found in summer, under warm, slow-flowing conditions, arise from anaerobic NO3- reduction. Locally, agricultural pollutants entering rivers are important C and N sources, providing ideal substrates for the aquatic bacteria involved in cycling of N. In this study a range of organic C compounds commonly found in agricultural pollutants were provided as energy sources in 48-h incubation experiments to investigate if the chemical compositions of the pollutants affected which NO3- reduction pathway was followed and influenced subsequent NO2- accumulation. Carbon stored within the sediments was sufficient to support DNRA and denitrifier populations, and the resulting NO2- peak (80 &mgr;g of N liter-1 [approximate]) observed at 24 h was indicative of the simultaneous activities of both bacterial groups. The value of glycine as an energy source for denitrification or DNRA appeared to be limited, but glycine was an important source of additional N. Glucose was an efficient substrate for both the denitrification and DNRA pathways, with a NO2- peak of 160 &mgr;g of N liter-1 noted at 24 h. Addition of formate and acetate stimulated continuous NO2- production throughout the 48-h period, caused by partial inhibition of the denitrification pathway. The formate treatment resulted in a high NO2- accumulation (1,300 &mgr;g of N liter-1 [approximate]), and acetate treatment resulted in a low NO2- concentration (<100 &mgr;g of N liter-1).
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PMID:Effects of carbon substrates on nitrite accumulation in freshwater sediments 987 60

Biotechnological techniques, including biofilters and biotrickling filters are increasingly used to treat air polluted with VOCs (Volatile Organic Compounds). In this work, the start-up, the effect of the gaseous ammonia addition on the toluene removal rate, and the problems of the heat accumulation on the performance of a laboratory scale biofilter were studied. The packing material was sterilized peat enriched with a mineral medium and inoculated with an adapted consortium (two yeast and five bacteria). Start-up showed a short adaptation period and an increased toluene elimination capacity (EC) up to a maximum of 190 g/m3/h. This was related to increased CO2 outlet concentration and temperature gradients between the packed bed and the inlet (Tm-Tin). These events were associated with the growth of the microbial population. The biofilter EC decreased thereafter, to attain a steady state of 8 g/m3/h. At this point, gaseous ammonia was added. EC increased up to 80 g/m3/h, with simultaneous increases on the CO2 concentration and (Tm-Tin). Two weeks after the ammonia addition, the new steady state was 30 g/m3/h. In a second ammonia addition, the maximum EC attained was 40 g/m3/h, and the biofilter was in steady state at 25 g/m3/h. Carbon, heat, and water balances were made through 88 d of biofilter operation. Emitted CO2 was about 44.5% of the theoretical value relative to the total toluene oxidation, but accumulated carbon was found as biomass, easily biodegradable material, and carbonates. Heat and water balances showed strong variations depending on EC. For 88 d the total metabolic heat was -181.2 x 10(3) Kcal/m3, and water evaporation was found to be 56.5 kg/m3. Evidence of nitrogen limitation, drying, and heterogeneities were found in this study.
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PMID:Start-up and the effect of gaseous ammonia additions on a biofilter for the elimination of toluene vapors. 1009 54

Carbon and nitrogen isotopic analysis of body tissues is one of the few techniques that can furnish quantitative information about the diet of archaeological humans. The study of the effects of various diets on modern human isotopic values can help to refine palaeodietary theories, and such work also enables the testing of palaeodietary theories independent of archaeological remains and interpretations. This report discusses the use of modern human hair as a sample material for isotopic analysis. The biogenic carbon and nitrogen isotopic signal is well preserved in hair, and the isotopic values of the keratin can be related to diet. We show that atmospheric and cosmetic contamination of hair keratin does not appear to affect the measured isotopic values. In a small study of Oxford residents, we demonstrate that the magnitude of the nitrogen isotopic values of hair keratin reflects the proportion of animal protein consumed in the diet: omnivores and ovo-lacto-vegetarians have higher delta15N than vegans. There was an observed relationship between the reported amount of animal protein eaten (either meat or secondary animal products) and the nitrogen isotopic values within the two groups of omnivores and ovo-lacto-vegetarians, indicating that an increasing amount of animal protein in the diet results in an increase in the delta15N of hair keratin. This provides the first independent support for a long-held theory that, for individuals within a single population, a diet high in meat equates to elevated nitrogen isotopic values in the body relative to others eating less animal protein. The implications of such results for the magnitude of the trophic level effect are discussed. Results presented here also permit a consideration of the effects of a change of diet in the short and long term on hair keratin isotopic values.
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PMID:Investigations into the effect of diet on modern human hair isotopic values. 1022 86

When Arthrobacter globiformis is grown in medium containing increased concentrations of NaCl or decreased levels of cations, the bacteria grow as clusters of branching myceloid cells. The sensitivities of salt-induced and citrate-induced myceloids to several environmental stresses were compared to those of normal exponential-phase bacilli and stationary-phase cocci. Salt-induced myceloids were more resistant than normal cells to ultraviolet light or heat shock at 45 degrees C but not to osmotic upshock or pH 4.3; citrate-induced myceloids showed an intermediate rate of heat inactivation. Carbon or nitrogen starvation of myceloids in the absence of added NaCl or citrate led to their division into single cells. Both myceloids and the single cells derived from them were more resistant than normal bacteria to nitrogen starvation. Salt-induced and citrate-induced myceloids showed reduced metabolism of many different carbon compounds in Biolog GP plates. These studies suggest that the formation of multicellular structures by A. globiformis is an adaptive response which increases its potential for survival.
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PMID:Adaptive characteristics of salt-induced myceloids of Arthrobacter globiformis. 1051 Jul 21


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