Accumulation Of Acetic Acid Research Articles

Accumulation and transport of (2,4-dichlorophenoxy)acetic acid in plant cuticles: I. Sorption in the cuticular membrane and its components

Partition coefficients ( K) of (2,4-dichlorophenoxy)acetic acid (2,4-D) have been determined for the system plant cuticle/aqueous buffer. Cuticles isolated enzymatically from leaves ( Clivia miniata, Ficus elastica, Citrus aurantium, Hedera helix, Pyrus communis cv. Conférence and cv. Williams, Olea europaea) and fruits ( Lycopersicon esculentum, Capsicum annuum, Solanum melongena, Cucumis sativus) were utilized. Only the nondissociated species of 2,4-D was sorbed by cuticles and their lipophilic components. The average partition coefficient for leaf cuticles was 316 (range, 240–470) and for fruit cuticles 476 (range, 424–579). The dependence of sorption upon 2,4-D concentration was tested using tomato fruit cuticle. The sorption isotherm was linear from 2.0 to 5.0 × 10 −4 mol m −3. With increasing 2,4-D concentrations partition coefficients decreased slightly. Extraction of soluble cuticular lipids (SCL) increased the partition coefficients and these relative increases were correlated to relative amounts of SCL. In most species the hydrolytic removal of polar cuticular components resulted in a further increase of partition coefficients. No single cuticle was found to be representative for the sorption characteristics of all plant species investigated. The amounts of cuticle present in plant communities can be estimated from the data presented in conjunction with leaf area indices.

Increased tryptophan uptake into the brain in hyperammonemia

Hyperammonemia was provoked in rats by urease injection over three days. Tryptophan transport into the forebrain measured by the bolus injection technique was increased in hyperammonemic rats in comparison with pairfed controls. The concentration of the large neutral aminoacids, of tryptophan and of 5-hydroxyindole acetic acid were increased in the forebrain and brainstem. Probenecid administration led to a significantly higher accumulation of 5-hydroxyindole acetic acid in the forebrain of hyperammonemic rats. Since liver function was not impaired the data indicate that hyperammonemia in absence of hepatic insufficiency alters the carrier function for large neutral aminoacids at the blood brain barrier.

Complete Heterolactic Acid Fermentation of Green Beans by Lactobacillus cellobiosis

ABSTRACTOnly Lactobacillus cellobiosus, among eight strains of heterofermentative lactic acid bacteria, removed all fermentable sugars from green beans. Proper blanching of the beans was required to prevent growth by natural lactic acid bacteria. An inoculum of 10 CFU/ml Lactobacillus plantarum and 106 CFU/ml L. cellobiosus resulted in the formation of twice as much lactic acid as inoculation with L. cellobiosus alone. A maximum of 3.74% sugar was metabolized by L. cellobiosus in bean juice containing 2.5% NaCI and 0.08% acetic acid. Fructose was nearly quantitatively reduced to mannitol with a concomitant accumulation of acetic acid. Ethanol was not observed until most of the fructose was metabolized. The L. cellobiosus‐fermented beans had a more mild acid flavor than beans fermented with L plantarum.

Effect of pH and Oxygen on Growth and Viability of Acetivibrio cellulolyticus

Growth, hydrogen production and cellulose digestion by Acetivibrio cellulolyticus strain CD2 were considerably greater when the culture pH was maintained at 70 than when the pH was not controlled. Furthermore, if the pH of the growth medium was controlled the number of viable organisms was 6-fold greater after 3 d incubation and 100-fold greater after 6 d incubation compared with equivalent cultures in which the pH was not controlled. The differences were due to the combined effect of low pH values and acetic acid accumulation. The number of viable organisms was 2- to 3-fold lower after 12 h incubation in substrate-free medium containing 40 mm-acetic acid at pH 55 than in the same medium at pH 70. Addition of 90 mm-acetic acid during growth in a cellobiose-containing medium lowered the growth rate by 30% and the rate of hydrogen production by 40%. Exposure of A. cellulolyticus to oxygen for up to 2 h did not affect viability measurements provided that the organisms were subsequently transferred to reduced media.

Cellulose degradation by a new isolate from sewage sludge, a member of the Bacteroidaceae family.

A mesophilic anaerobe, a member of the Bacteroidaceae family (NRC2248), isolated from a cellulose-enrichment culture, digested untreated Whatman cellulose powder and HCl-treated cotton battings while producing hydrogen, carbon dioxide, cellobiose, glucose, and acetic acid as the sole volatile acid. This organism also utilized cellobiose as carbon and energy source but did not utilize glucose. It grew well in synthetic medium containing ammonium salts as nitrogen source and having a pH value of 7.0-7.1 and an Eh value of -160mV or lower. The nutrient requirements of this organism were found to be similar to those of other anaerobes except for Na2S which inhibited cellulose degradation in concentrations above 0.75 mM. Best cellulose degradation occurred under an atmosphere of 80% N2-20% CO2. Use of H2 or 80% H2-20% CO2 as headspace gas inhibited growth. Although accumulation of acetic acid in about 15-16 mM concentrations inhibited the further formation of H2, CO2, and acetic acid in the broth, it did not stop the degradation of cellulose. The results indicate that this organism has the ability to grow in media containing up to 20 g/L of cellulose and to produce industrially important and easily separable end products from cellulose.

The effect of pronounced hypoglycemia on monoamine metabolism in rat brain.

The cerebral metabolism of catechol and indole amines was studied in paralyzed and lightly anesthetized (70% N2O) rats in which severe hypoglycemia was induced by insulin. When blood glucose concentrations fell towards 1 μmol·g−1 and the electrocorticogram (EEG) showed high-amplitude slow waves with interspersed polysplkes, the tissue contents of dopamine (DA), norepinephrine (NE), and 5-hydroxytryptamine (5-HT) were reduced. The rate of hydroxylation of tyrosine, measured as accumulation of dihydroxyphenylalanine (dopa) following inhibition of aromatic L-amino acid decarboxylase with NSD 1015, rose in cortex and striatum, while tryptophan hydroxylation increased moderately in cortical tissue. Aggravation of the hypoglycemia with cessation of spontaneous EEG activity was accompanied by progressive reduction in tissue contents of DA, NE, and 5-HT and by accumulation of 5-hydroxyindole acetic acid (5-HIAA). In this period, tyrosine hydroxylation rate was reduced in limbic areas and in striatum, but not in the cortex, while tryptophan hydroxylation was reduced in limbic areas only. When recovery was induced for 45 min by i.v. glucose following 30 min recording of isoelectric EEG, there was extensive recovery of tissue concentrations of DA and 5-HT but incomplete recovery of NE concentrations. Tyrosine hydroxylation rate was increased in all areas, but tryptophan hydroxylation either remained at control levels (striatum and cortex) or fell (limbic area). It is concluded that severe hypoglycemia leads to a gross derangement of brain monoamine metabolism, which seems to include an increase in NE turnover during both the precomatose phase and the recovery phase.

Effects of carbon dioxide and methane on methanogenesis

A mixed microbial culture, enriched from sewage sludge, was cultivated on a glucose medium in a high turbulence fermentor at constant temperature, pH and loading rate. Effects of high pCO2 (0.95 atm) and pCH4 (0.90 atm) were compared to those of low pCO2 (0.05 atm) and pCH4 (0.05 atm). Generally, rapid in creases in pCO2 resulted in rapid decreases in methane production and, conversely rapid decreases in pCO2 by N2-sparging resulted in rapid increases in methane production. Decreased values of methane production were also accompanied by acetic acid accumulation. No inhibiting effects of high pCH4 were detected. A method to obtain low pCO2 by gas recycling combined with CO2-absorption is proposed.

Accumulation of (2,4‐dichlorophenoxy) acetic acid and (2,4,5‐trichlorophenoxy) acetic acid by Parenchyma Tissue as Influenced by Metabolic Inhibitors and Lecithin

AbstractParenchyma tissue from potato (Solanum tuberosum L. cv. Russet) tubers was treated with inhibitors to the release of metabolic energy in order to determine the importance of an active transport system for (2,4‐dichlorophenoxy)acetic acid (2,4‐D) and (2,4,5‐trichlorophenoxy)acetic acid (2,4,5‐T) accumulation. Results from treatments with carbonylcyanide m‐chlorophenylhydrazone, an inhibitor of oxidative phosphorylation, and N,N'‐dicyclohexylcarbodiimide, an inhibitor of membrane‐bound adenosine triphosphatase, indicated 2,4‐D and 2,4,5‐T accumulation to be independent of available energy as influenced by these metabolic inhibitors. Lecithin treated parenchyma tissue accumulated more 2,4‐D and 2,4,5‐T than untreated tissue indicating possible binding of the herbicide to the lecithin moiety.

Production of Acetic Acid from Ethanol by Wine Yeasts

A local strain of the typical wine yeast <i>Saccharomyces cerevisiae</i> var. <i>ellipsoideus</i> was found to accumulate acetic acid in a liquid medium with ethanol under aerobic conditions. Acetic acid accumulation was studied in relation to the initial concentration of alcohol. Acetic acid accumulation (6g per liter) was maximum in media whose initial alcohol concentration was around 4% (v/v). The accumulation fell off rapidly at initial ethanol concentrations higher than 6%. The results, of interest to enologists are also discussed from the taxonomic point of view.

CARBOHYDRATE METABOLISM OF STAPHYLOCOCCUS AUREUS.

SUMMARY: The experiments described establish the importance of the pentose cycle in carbohydrate breakdown by Staphylococcus aureus. No Entner-Doudoroff pathway was found. Another feature is the extensive glucose effect: growth in glucose enhanced glycolysis suppressed the Krebs cycle, decreased the activity of the pentose cycle and suppressed the formation of many enzymes. Even the oxidation of pyruvic acid was decreased in glucose-grown organisms. The decrease of oxidative activity affected the cytochromes. The main products of carbohydrate oxidation were acetic acid and carbon dioxide. The accumulation of acetic acid indicated that the link between pyruvic acid and the citric acid cycle was weak.

細菌の代謝に於けるKCN. NaN&lt;sub&gt;3&lt;/sub&gt;の作用

Using the standard strains such as Sh. flexneri 2 a, St. aureus and St. albus that are stocked in our laboratory, the author studied the glucolysis of these bacteria in the course of culture in the medium containing KCN or NaN3, and also compared the enzymatic benaviors of each kind of bacteria in resting state while being cultured in the medium loaded with KCN or NaN3. The results are as follows:1. Both Sh. flexneri 2 a and St. aureus grow well in the medium loaded with 10-3M KCN or NaN3, and in the medium loaded with 10-3M KCN th growth of St. albus is somewhat impeded but this strain grows well in the medium loaded with 10-2M NaN3.2. When KCN or NaN3 is added to the medium in the course of bacteria culture, the glycolysis tends to be anaerobic; and morever, by the addition of KCN the accumulation of lactic acid increases, while by the addition of NaN3 the accumulation of acetic acid.3. On comparing the catalase and peroxidase activities of bacteria cultured in the medium loaded with KCN or NaN3, both Sh. flexneri 2 a and St. albus lose their catalase and peroxidase activities in the medium loaded with 10-4M KCN or NaN3; while St. aureus likewise does not show these enzymatic activities in the medium loaded with 10-4M NaN3, but this strain retains these enzymatic activities to a marked degree in the medium loaded with 10-2M KCN.4. In these bacteria being cultured in the medium containing KCN the enzymatic activity of lactic acid production from glucose is great, while in these bacteria cultured in the medium containing NaN3 the acetic acid production from glucose is great.

Utilization of acetate in experimental diabetes.

IT is well known that acetic acid occupies an important place in the intermediary metabolism, and that the participation of this substance in many reactions requires the activation of the acetate molecule. It is now generally considered that ‘active acetate’ corresponds to acetyl coenzyme A. Therefore, it appears reasonable to assume that a reduction of the acetylation of coenzyme A, that is, of the formation of ‘active acetate’, would lead to the accumulation of acetic acid.