Showing papers on "Acetic acid published in 1986"

Acetate oxidation to CO2 in anaerobic bacteria via a novel pathway not involving reactions of the citric acid cycle

Abstract: In several sulfate-reducing bacteria capable of complete oxidation of acetate (or acetyl CoA), the citric acid cycle is not operative. No 2-oxoglutarate dehydrogenase activity was found in these organisms, and the labelling pattern of oxaloacetate excludes its synthesis via 2-oxo-glutarate. These sulfate-reducers contained, however, high activities of the enzymes carbon monoxide dehydrogenase and formate dehydrogenase and catalyzed an isotope exchange between CO2 and the carboxyl group of acetate (or acetyl CoA), showing a direct C-C-cleavage of activated acetic acid. These findings suggest that in the investigated sulfate-reducers acetate is oxidized to CO2 via C1 intermediates. The proposed pathway provides a possible explanation for the reported different fluoroacetate sensitivity of acetate oxidation by anaerobic bacteria, for mini-methane formation, as well as for the postulated anaerobic methane oxidation by special sulfate-reducers.

New C-4-chiral 1,3-thiazolidine-2-thiones: excellent chiral auxiliaries for highly diastereo-controlled aldol-type reactions of acetic acid and .alpha.,.beta.-unsaturated aldehydes

Abstract: Synthese d'hydroxy-3' alcene-4' oyl-3 alkyl-4 thiazolidinethiones-2 par reaction d'acetyl-3 alkyl-4 thiazolidinethiones-2 avec des enaldehydes en presence de triflate d'etain II et d'ethyl-1 piperidine

Macrophage activation with multi-porous beads prepared from partially deacetylated chitin

Abstract: The effect of multi-porous beads prepared from 80% deacetylated chitin on the activation of mouse peritoneal macrophages was examined. Deacetylated chitin bead (DAC-bead) preparations were shown to activate macrophages for tumoricidal activity depending on the increasing concentration of acetic acid used for the pretreatment of beads. The large DAC-bead was more susceptible to treatment with acetic acid than small DAC-bead, and showed more potent capacity for the activation of macrophages under the same pretreatment conditions with acetic acid. Deacetylated bead preparations, on the other hand, showed less activities. In addition, DAC-bead pretreated with acetic acid stimulated macrophages to produce interleukin 1. The possibilities of multi-porous beads as cancer chemotherapeutic-carrier were examined by the method of column chromatography and of in vitro antitumor experiment. Forty-four percent of adriamycin adsorbed on the surface of and in bead was released within the first 60 min. of elution, and then adriamycin was released more slowly in proportion to the elution time. Antitumor activity of adriamycin-adsorbed bead was less effective than that of free adriamycin if they were compared on the basis of total content of adriamycin.

Electronic spectroscopy of tryptophan analogs in supersonic jets: 3‐Indole acetic acid, 3‐indole propionic acid, tryptamine, and N‐acetyl tryptophan ethyl ester

Abstract: The electronic spectroscopy of four different tryptophan analogs, 3‐indole acetic acid, 3‐indole propionic acid, tryptamine, and N‐acetyltryptophan ethyl ester (NATE) has been studied in a supersonic molecular beam using laser‐induced fluorescence and resonantly enhanced two‐photon ionization. The electronic transition to the lowest excited singlet state occurs at 35 039, 34 965, 34 918, and 34 881±2 cm−1 for 3‐indole acetic acid, 3‐propionic acid, tryptamine, and NATE, respectively. The relatively small differences in the electronic origin transition frequencies suggests that the lowest excited singlet state for all of these moelcules is the 1Lb state. The spectra reveal that each of these molecules have stable conformers in the gas phase, analogous to our previously reported studies of tryptophan. A low frequency vibrational mode has been observed in 3‐indole propionic acid, tryptamine, NATE, and tryptophan which involves motion of the side chain against the indole ring. We have observed that forming a van der Waals complex between tryptamine and a single methanol molecule causes the spectral features due to different conformers of the free molecule to collapse to a single line, suggesting that one particular conformer becomes the most stable species. This emphasizes the importance of including solvent interactions in any attempt to model the behavior of these molecules in solution.

Chemical processing of lignocellulosics

Abstract: Lignocellulosics can be separated into their three main components by extraction with acetic acid, containing 0.1% hydrogen chloride, at 110°C. The residual pulp can be bleached in the same solvent with peracetic acid, which is formed in situ when adding hydrogen peroxide. Hemicelluloses and lignin are obtained in a low condensed and relatively reactive form that may be converted into valuable chemical raw materials. Some aspects of such conversions are discussed.

Fermentative Metabolism of Chlamydomonas reinhardii: III. Photoassimilation of Acetate.

Abstract: The anaerobic photodissimilation of acetate by Chlamydomonas reinhardii F-60 adapted to a hydrogen metabolism was studied utilizing manometric and isotopic techniques. The rate of photoanaerobic (N2) acetate uptake was approximately 20 μmoles per milligram chlorophyll per hour or one-half that of the photoaerobic (air) rate. Under N2, cells produced 1.7 moles H2 and 0.8 mole CO2 per mole of acetate consumed. Gas production and acetate uptake were inhibited by monofluoroacetic acid (MFA), 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU) and by H2. Acetate uptake was inhibited about 50% by 5% H2 (95% N2). H2 in the presence of MFA or DCMU stimulated acetate uptake and the result was interpreted to indicate a transition from oxidative to reductive metabolism. Carbon-14 from both [1-14C]- and [2-14C]acetate was incorporated under N2 or H2 into CO2, lipids, and carbohydrates. The methyl carbon of acetate accumulated principally (75-80%) in the lipid and carbohydrate fractions, whereas the carboxyl carbon contributed isotope primarily to CO2 (56%) in N2. The presence of H2 caused a decrease in carbon lost from the cell as CO2 and a greater proportion of the acetate was incorporated into lipid. The results support the occurrence of anaerobic and light-dependent citric acid and glyoxylate cycles which affect the conversion of acetate to CO2 and H2 prior to its conversion to cellular material.

Alcohols production by hydrogenation of carboxylic acids

Abstract: Ethanol is produced from acetic acid or propanol is produced from propionic acid by contacting either acetic acid or propionic acid in the vapor phase with hydrogen at elevated temperature and a pressure in the range from 1 to 150 bar in the presence of a catalyst comprising as essential components (i) a noble metal of Group VIII of the Periodic Table of the Elements, and (ii) rhenium, optionally on a support, for example a high surface area graphitized carbon.

Growth Regulators Have Rapid Effects on Photosynthate Unloading from Seed Coats of Phaseolus vulgaris L.

Abstract: Of nine plant growth regulators (indoleacetic acid, 1-naphthalene acetic acid, gibberellic acid, giberellin 4/7, 6-benzylaminopurine, 6-furfurylaminopurine, abscisic acid, and 1-aminocyclopropane carboxylic acid) tested, only 6-benzylaminopurine and abscisic acid affected 14C-photosynthate unloading from excised seed coats of Phaseolus vulgaris L. Unloading, in the presence of KCl, was stimulated by 25 to 40%. Stimulation occurred immediately for 6-benzylaminopurine and for abscisic acid within 10 to 12 minutes of application.

Process for the hydrogenation of acetic acid

Abstract: Acetic acid is hydrogenated in vapour phase to produce ethanol in free form or in the combined form of ethyl acetate. The catalytic process now found takes place in relatively moderate temperature and pressure conditions, with a view to producing ethanol and/or ethyl acetate, and is characterised in that the catalyst consists of ruthenium deposited on a silica support. A process for manufacturing the catalyst is also claimed.

Heterocyclic oxophthalazinyl acetic acids

Abstract: A heterocyclic oxophthalazinyl acetic acid having aldose reductast inhibitory activity of the formula ##STR1## wherein X is oxygen or sulfur; Z is a covalent bond, O, S, NH or CH2 or CHR5 Z is vinyl; R1 is hydroxy, or a prodrug group; R2 is a heterocyclic group, R3 and R4 are hydrogen or the same or a different substituent, and R5 is hydrogen, methyl or trifluoromethyl The pharmaceutically acceptable acid addition salts of the above compounds wherein R1 is di(C1 -C4)alkylamino or (C1 -C4)alkoxy substituted by N-morpholino or di(C1 -C4)alkylamino and the pharmaceutically active base addition salts of the above compounds wherein R1 is hydroxy are also aldose reductase inhibitors

Adjusting the polymerization time of isobutyl-2 cyanoacrylate.

Abstract: Isobutyl-2 cyanoacrylate (IBCA) polymerizes by an anionic mechanism. The initiation of polymerization depends on an alkaline medium and can be inhibited with the addition of small amounts of acid. Using small amounts of glacial acetic acid (3.7%-7.1% by volume), the polymerization time was prolonged from 2.3 sec to 7.8 sec. In vivo experiments in dogs demonstrated no additional inflammatory reactions to the mixture of IBCA, iophendylate, and tantalum powder when acetic acid was added. Glacial acetic acid offers a safe and effective way, without increase in viscosity, to manipulate the polymerization time of IBCA.

Continuous release pharmaceutical compositions formed by freeze drying acetic acid solutions of polylactide

Abstract: Pharmaceutical compositions, comprising a polylactide and a pharmacologically active, acid stable polypeptide, which when placed in an aqueous physiological equipment release the polypeptide at an approximately constant rate in an essentially monophasic manner, with a minimal, or no induction period prior to the release; polylactides suitable for use in said compositions; and a method for the manufacture of such polylactides.

Hexaazatriphenylene hexanitrile and its derivatives and their preparations

Abstract: Hexaazatriphenylene hexanitrile and various derivatives therefrom including its hexacarboxamide, hexacarboxylic acid and hexaacid salts and metal complexes, lower alkyl hexaesters of the hexacarboxylic acid, and hexacarboxylic trisanhydride are described along with their preparations initiating with reacting hexaketocyclohexane octahydrate with excess diaminomaleonitrile in acetic acid, preferably at reflux temperature, to provide the hexanitrile from which the other derivatives are prepared.

Effect of defaunation and refaunation of the rumen on rumen fermentation and N-flow in the duodenum of sheep

Abstract: In order to confirm earlier fragmentary results, the effect of defaunation and refaunation of the rumen on the fermentation pattern and flow of N-components in the proximal duodenum of two sheep was investigated. Defaunation had no effect on acetic acid as a proportion of the total volatile fatty acids in the rumen, while the proportions of propionic acid increased with a concomitant decrease in butyrate. Refaunation resulted in lower acetic acid and higher butyric acid proportions. The concentration of ammonia N in the rumen was clearly decreased after defaunation, already indicating an effect of the elimination of protozoa on nitrogen metabolism in the rumen. Defaunation also increased significantly the flow of total N, non ammonia N and individual and total amino acids in the proximal duodenum. Defaunation resulted in higher bacterial growth efficiency, significantly in one sheep, but the decrease after refaunation was statistically significant for both sheep. Determination of rumen digestibility of organic matter and acid detergent fibre (ADF) revealed lower values in the absence of the protozoa, while total digestibility was only influenced to a much lower extent. This indicated a shift of digestion from rumen to the lower digestive tract. Finally, earlier work is discussed in the light of the present findings.

Toxicity of organic acids for repair-deficient strains of Escherichia coli.

Abstract: The wild-type strain and four DNA repair-deficient strains (uvrA6, uvrB5, recA56, and polA1) of Escherichia coli K-12 were treated with acetic acid, lactic acid, and p-aminobenzoic acid at pH 3.5 during their stationary phase of growth. All three acids were highly toxic to the polymerase-deficient strain. The greater sensitivity of the strain carrying the polA1 gene than its isogenic pol+ derivatives suggested that damage caused by acidity requires polA+ gene products for repair.

Nutritional and germination requirements of the rumen chytridiomycete Neocallimastix patriciarum

Abstract: The anaerobic rumen chytridiomycete Neocallimastix patriciarum was grown in vitro in a defined medium. Minimal nutritional requirements for growth on cellobiose in a CO 2 atmosphere were satisfied by the provision of haemin, thiamin, d -biotin, ammonium ions and a reduced source of sulphur. Growth was stimulated by amino acids, acetic acid, iso -butyric acid, 2-methyl butyric acid, low concentrations of long-chain fatty acids, nicotinic acid, nicotinamide, cyanocobalamin, riboflavin, inositol, pyridoxine hydrochloride, pyridoxal phosphate, and pyridoxamine. Germination of zoospores was stimulated by acetic acid and soluble fermentable carbohydrates. The optimum pH and temperature for germination was pH 5.5–6.4 and 38–40 °C.

Organic acids and glycerol in beer

Abstract: The concentrations of pyruvic acid, citric acid, L-malic acid, acetic acid, L-lactic acid and glycerol were determined in beers of different type and origin. Large differences in organic acid and glycerol contents were found, especially between different types of beer. The amounts of acetic acid, lactic acid and glycerol can be used as process parameters. During malting a decrease of the malic acid-citric acid ratio occurred due to the pathway of the TCA-cycle. The acetic acid content and glycerol contents showed increases during fermentation. The latter parameter is useful to indicate if alcohol-free beer has been produced by fermentation. Determination of apparent final attenuation degrees of worts according to the usual laboratory practice resulted in higher glycerol contents than was found for the corresponding beers, making the value of this assay questionable.

The forms of cobalt in some Scottish soils as determined by extraction and isotopic exchange

Abstract: SUMMARY The results of fractionation and correlation studies provided evidence that cobalt in soils is associated predominantly with the soil oxide fraction, particularly the manganese oxides. Only a small proportion of the total cobalt present in soils was extracted by acetic acid, EDTA, pyrophosphate or hydroxylamine. Cobalt extracted with these reagents was considered to be derived principally from easily reducible manganese oxides, although the origin of the cobalt extracted by acetic acid in particular was not well defined. The bulk of the cobalt present in soils appeared to be occluded by more highly crystalline oxide materials or was present in the structures of primary and secondary minerals. Labile cobalt in soil was assessed by extraction with acetic acid and EDTA and by determination of isotopically exchangeable cobalt. The amounts of cobalt extracted by both EDTA and acetic acid were highly dependent on the length of extraction period and on the temperature of extraction. Neither of these reagents appeared likely to give good estimates of the quantity or intensity factors of soil cobalt supply to plants as defined by the isotopic exchange determinations.

Reaction of thiobarbituric acid with saturated aldehydes.

Abstract: The reaction of thiobarbituric acid (TBA) with saturated aldehydes, i.e., 1-butanal, 1-hexanal and 1-heptanal, produced a 455-nm yellow and a 532-nm red pigment. Formation of the pigments depended on the reaction conditions. The yellow pigment was unstable in the presence of excess amounts of the saturated aldehydes. The red pigment was formed only when the reaction was performed at a TBA/aldehyde ratio of 1:1 in aqueous acetic acid. Formation of the yellow and red pigments required molecular oxygen. The colorless adducts, intermediates for the yellow and the red pigments, were isolated from the reaction mixtures. Aldol condensation and dehydration of 2 mol of the saturated aldehydes initially gave the alpha, beta-unsaturated aldehydes, which in turn reacted with TBA to form the colorless adducts, pyranopyrimidine derivatives. The adducts were then converted into the yellow and red pigments under aerobic conditions.

A comparative study of the biodegradation of the surfactant sodium dodecyltriethoxy sulphate by four detergent-degrading bacteria.

Abstract: Summary: The 35S-labelled metabolites produced during biodegradation of sodium dodecyltriethoxy [35S]sulphate (SDTES) by four bacterial isolates were identified and quantified. All four isolates used ether-cleavage as the predominant primary degradation pathway. In two of the organisms, the etherase system (responsible for approx. 60–70% of primary biodegradation) liberated mono-, di- and triethylene glycol monosulphates in substantial proportions, the last two esters undergoing some further oxidation to acetic acid 2-(ethoxy sulphate) and acetic acid 2-(diethoxy sulphate), respectively. For these isolates, liberation of SO4 2- directly from SDTES was also significant (30–40%) and the organisms were shown to contain alkylsulphatases active towards SDTES. For the remaining two isolates, etherase action was even more important (responsible for <80% of primary biodegradation) and was restricted almost totally to the alkyl–ether bond to generate mainly triethylene glycol sulphate, some of which was further oxidized. Very small amounts of diethylene glycol monosulphate were also produced, but its mono-homologue, and the oxidation products of both these esters, were absent. Small amounts of inorganic sulphate (approx. 10%) were liberated by these isolates and one of them also produced compounds tentatively identified as intermediates of βoM-oxidation.

Non-Steroidal Anti-Inflammatory Analgesics Other than Salicylates

Abstract: The largest group of non-narcotic analgesics are the arylalkanoic acid derivatives, comprising derivatives of arylacetic acid, propionic acid, heteraryl acetic acid and indole acetic acid. Common to all of these drugs is their inhibition of prostaglandin biosynthesis, which contributes to their analgesic and other pharmacological properties as well as to their principal side effect, gastrointestinal irritation. Although these drugs all cause some gastric microbleeding, they do so to a lesser extent than aspirin. The arylalkanoic acid derivatives, as well as the anthranilic acid and oxicam derivatives, are peripherally acting as evidenced by their lack of activity in classical tests of central analgesic activity. After oral administration of these drugs, their peak plasma concentrations are generally attained in 1 to 3 hours; absorption is not generally influenced by food. Volume of distribution is mostly low (less than 0.2 L/kg) and protein binding is high (usually 95 to 99%). Elimination is by glucuronide formation for several of the propionic acid derivatives and generally by biotransformation for derivatives of arylacetic acid, indole and indene acetic acid, and the oxicams. The elimination half-life of the arylalkanoic acid derivatives is in most instances about 2 to 5 hours, although notable exceptions include carprofen (approximately equal to 20 h), fenbufen (10 h), naproxen (12-15 h) and sulindac (16 h for the active metabolite). The elimination half-life of indomethacin varies considerably between and within individuals. Piroxicam has the longest half-life, averaging 45 hours. The pharmacokinetic properties of the anthranilic acid derivatives (fenamates, glafenine) generally resemble those of the arylacetic acids. Few clinically significant drug interactions are associated with concomitant administration of the arylalkanoic acids or piroxicam and other drugs. Since the arylalkanoic acids are highly bound to plasma proteins (mainly albumin) there is a theoretical potential for displacement reactions with drugs that are used at plasma concentrations high enough to exceed the binding capacity of their own primary binding sites. However, such reactions have rarely been reported. Although the concomitant administration of aspirin and several of the propionic acid derivatives results in a significant decrease in the plasma concentration of the latter, the clinical significance of such interactions is uncertain and probably minimal.(ABSTRACT TRUNCATED AT 250 WORDS)