High Levels Of Acetate Research Articles

Effect of pyruvate on glucose metabolism in Clostridium acetobutylicum

Pyruvate effects on the metabolism of Clostridium acetobutylicum during glucose fermentation were studied. After addition to the culture medium, the pyruvate was rapidly used, provoking several changes in the metabolic pattern of the bacteria. When pyruvate addition occurred early in the fermentation, the glucose utilization decreased and the solventogenic phase was not induced. When pyruvate was added during solventogenesis, glucose consumption was slightly affected and the cells fermented both substrates simultaneously: however, the acidogenic phase started again to the detriment of solvent formation. Usually, during the solvent phase, the cells remetabolized acetic and butyric acids into solvents, but when pyruvate was added, the utilization of acids was stopped and the specific rates of acetate and butyrate formation increased immediately. The acidogenic growth phase was characterized by high levels of acetate and butyrate kinase which dropped during the solvent phase. Addition of pyruvate limited the down shift of these two enzymes and the levels of the activities remained constant during the course of the fermentation. Conversely, the acetoacetate decarboxylase, which is characteristic of the solvent phase, decreased sharply in the presence of pyruvate. The fact that the specific rate of glucose consumption was not decreased by the pyruvate metabolism, a cosubstrate, proves that the phosphoroclastic reaction is not a limiting step. Furthermore, the pyruvate utilization represented a promising approach to obtain useful data on the intracellular compounds implicated in the mechanism for switching from the acidogenic to the solventogenic phase.

Trace element speciation by anodic stripping voltammetry: The effects of added mercuric and acetate ions

Acetate buffers are often added to water samples prior to trace metal speciation analysis by anodic stripping voltammetry (ASV), and the addition of mercuric ion is also necessary if a thin mercury film electrode (TMFE) with in situ mercury deposition is used. The effects of mercuric and acetate ions on the percentage of labile zinc, cadmium, lead and copper were measured at both the TMFE and a hanging mercury drop electrode in a synthetic soft water containing various ligands, and in a natural and a polluted river water. The results showed that the concentrations of acetate (0.03 M) and mercuric ions (2–4 × 10 −5 M) normally used in ASV speciation analysis are unlikely to have a significant effect on labile metal measurements. However, high (0.15 M) acetate levels can cause an increase in labile metal in some water samples.

Influence of Dietary Retinyl Acetate on Normal Rat Mammary Gland Development and on the Enhancement of 7,12-Dimethylbenz[<italic>a</italic>]anthracene-Induced Rat Mammary Tumorigenesis by High Levels of Dietary Fat<xref ref-type="fn" rid="FN2">2</xref>

The effect of high levels of dietary fat and retinyl acetate (ROA) on 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumor development and growth was examined. Female Sprague-Dawley rats, 51-53 days of age, were treated ig with 5 mg DMBA. At 55-57 days of age, the animals were divided into the following dietary treatment groups: A) 4.5% fat [control fat (CF)]; B) CF + 1.0 mmol ROA/kg diet (CF + ROA); C) 20.0% fat [high fat (HF)]; and D) HF + ROA. HF diets significantly increased mammary tumor multiplicity, with or without ROA, but did not significantly influence mammary tumor growth. ROA treatment reduced mammary tumor multiplicity regardless of the level of dietary fat and inhibited mammary tumor growth in the presence of normal levels of dietary fat. High levels of dietary fat did not significantly influence normal mammary gland growth and development. ROA significantly decreased normal mammary gland growth and development regardless of the level of dietary fat. Blood retinoids in rats fed ROA were primarily in the form of retinyl esters, i.e., retinyl linoleate, retinyl palmitate-oleate, and retinyl stearate. Free retinol levels in blood were not significantly influenced by ROA feeding. Blood retinyl ester levels were lower in rats fed the HF + ROA diet as compared to rats fed the CF + ROA diet.

Acetylation of histones during spermatogenesis in the rat

Acetate was actively incorporated into rat testis histones when testis cells were prepared by the trypsinization technique in the presence of [ 3H]acetate. The acetylation was enhanced by 10 m m sodium butyrate. Although histones H3 and H4 were the only histones which incorporated high levels of acetate, the testis-specific histones TH2B and TH3 also appeared to incorporate acetate. This was shown by electrophoresis of the histones on polyacrylamide gels containing Triton X-100. Results, obtained from analysis of histones by two-dimensional gel electrophoresis, confirmed a recent report (P. K. Trostle-Weige, M. L. Meistrich, W. A. Brock, K. Nishioka, and J. W. Bremer, (1982) J. Biol. Chem. 257, 5560–5567) that TH2A was a testis-specific histone. The results also confirmed the H2A nature of a testis-enriched histone band, previously designated X2. When histones from populations of cells enriched in specific testis cell types, representing various stages of spermatogenesis, were examined, the patterns of acetylation varied dramatically. Very high levels of acetate were incorporated into multiacetylated species of histone H4 from a population of cells enriched in transition stage spermatids (steps 9–12) compared to the levels of acetate incorporated into H4 from round spermatids (steps 1–8) and earlier stages of spermatogenesis, where acetate was incorporated primarily into the monoacetylated species of H4. Thus, a striking correlation exists between the time of hyperacetylation of histone H4 and the time of removal of histones for their replacement by the basic spermatidal transition proteins designated TP, TP2, and TP4. Hyperacetylation of histone H4 may facilitate the removal of the entire histone complement during the protein transition. In any case, it must be an obligatory step in the dramatic process.

Preliminary studies of lavender as an essential oil crop for New Zealand

Abstract Solvent extraction and gas Chromatographic techniques were used to assess the quality of oil obtained from as few as 5 lavender florets. Oil samples from 18 accessions of 2 species were analysed to select those producing oil of superior quality for further tests of yields and commercial acceptability. Only accessions with high linalyl acetate levels, low camphor levels, and linalyl acetate: linalool ratios of greater than one were retained. In 2 accessions, oil yields and composition were examined at different stages of inflorescence maturity. The best harvest time appears to be between full bloom and withering of half of the florets. Oil yield and composition were also followed for 24 h periods. Oil contents were severely reduced in plants in the field during hot windy conditions.

Variations au cours de la journée des teneurs en certains constituants plasmatiques chez la jument poulinière

Twenty-one circadian blood sample profiles were made in heavy brood mares during pregnancy, lactation or the dry, non-pregnant period. The mares were fed forage-rich diets containing different levels of energy and nitrogen (table 1). Each profile consisted of 7 samples taken at 8 a.m., 11 a.m., 3 p.m., 7 p.m., 11 p.m., 4 a.m. and 8 a.m. The animals were fed at 8:30 a.m. The eleven plasma components evaluated were glucose, non-esterified fatty acids, beta-hydroxybutyrate, acetate, alanine, insulin (energy metabolites), urea, total protein (nitrogen metabolites), calcium, inorganic phosphorus and magnesium (mineral metabolites). Profile results are shown in table 2 and figure 1. Glucose, insulin and alanine increased and non-esterified fatty acids, acetate and beta-hydroxybutyrate decreased during the prandial period (between 8 a.m. and 11 a.m.). The glucose and insulin peaks were short, while the other components returned slowly to preprandial values. Acetate and beta-hydroxybutyrate were maximal during the night, while urea increased moderately during the prandial period. Protein concentration did not vary. The effect of feeding on minerals was moderate: there was a slight increase in calcium and magnesium and a decrease in phosphorus. The following differences were related to diet or physiological state (figs. 2, 3, 4): --higher glucose and insulin peaks when concentrate intake was high; --lower circadian variation of non-esterified fatty acids, beta-hydroxybutyrate and acetate in dry, non-pregnant, well-fed mares; --higher acetate levels with a high-forage diet; --more rapid alanine decrease during late pregnancy than in early lactation; --higher circadian variations in minerals during lactation than during pregnancy. The prandial variations of the following factors were significantly correlated (table 3): --glucose and insulin, --acetate and beta-hydroxybutyrate, --beta-hydroxybutyrate and non-esterified fatty acids, --acetate and non-esterified fatty acids. The origin of these variations is discussed. Two factors intervened: 1) exogenous production Very rapid digestion of the concentrate induced an increase in glucose (and thus in insulin) and alanine. The volatile fatty acids produced in the hindgut caused nocturnal peaks of acetate and beta-hydroxybutyrate; 2) a lipogenic phase (which began after mean meal intake) alternating with a lipolytic phase, providing constant coverage of the energy needs. This explains the large post-prandial decreases in non-esterified fatty acids, acetate and beta-hydroxybutyrate.

The effect of irrigation and nitrogen on the yield and composition of peppermint oil (Mentha piperita L.)

Peppermint was harvested twice during the growing season. Harvest 1 was conducted on 16 February 1979, and the subsequent regrowth was harvested on 25 April 1979. High peppermint oil yields were associated with high rates of nitrogen fertilizer (100, 200 and 300 kg nitrogen/ha), and high levels of irrigation (50 mm per week) throughout the last half of the growing season. The composition of oil extracted from herb at the commercial harvest date was not significantly affected by either nitrogen or irrigation treatments. The oil yield from regrowth within the same growing season was significantly affected by irrigation and nitrogen treatments applied prior to the first harvest. When 300 kg nitrogen/ha and 50 mm of irrigation weekly (during the last half of the growing season) were applied, the oil yields from regrowth approached the commercial yield obtained from one harvest. Oil from regrowth contained high levels of menthol, menthyl acetate, menthofuran and limonene, and low levels of menthone and cineole. The possibility of obtaining two commercial harvests of peppermint per season, under southern Tasmanian conditions, is discussed

Differential translation of rat liver albumin messenger RNA in a wheat germ cell-free system.

Rat liver polysomal RNA directs the synthesis of albumin in a wheat germ cell-free system. The in vitro product has the same mobility in polyacrylamide-sodium dodecyl sulfate gels as purified rat liver albumin and can be immune precipitated with rabbit anti-rat liver albumin serum. The incorporation of [35S] methionine into total protein in an in vitro system increased linearly with increasing messenger RNA concentration until a saturation plateau was reached. The synthesis of albumin compared to total protein increased continually with increasing RNA concentration. Addition of the polynucleotide poly(A) to the cell-free system inhibited incorporation, presumably through interference with the initiation process, and increased the relative albumin synthesis. Translation of albumin messenger RNA was also resistant to inhibition by high levels of potassium acetate where total incorporation was cut in half. The results suggest that the messenger RNA for albumin, in addition to the mRNAs for the beta chain of globin and for the immunoglobulin polypeptides, is particularly efficient in initiating protein synthesis.

Comparative Selenium Retention by Chicks Fed Sodium Selenite, Selenomethionine, Fish Meal and Fish Solubles

Two experiments were conducted to assay the retention of Se from varying levels of fish meal and solubles and in the second experiment to compare also the retention with that from comparable levels of sodium selenite and selenomethionine. The basal diet contained crystalline amino acid diets and high levels of α-tocopherol acetate (200 and 300 p.p.m.). In the first experiment day-old chicks were found to contain 11 μg. Se whereas chicks fed the basal diet for 21 days without any Se supplements contained 37% less. In the second experiment the day-old chicks started with a body reserve of 13 μg. Se, of which 35% was lost when fed the basal diet for 18 days.A Se balance in the chick was maintained by a dietary level of 0.05 p.p.m. from any of the sources studied. This quantity of Se was supplied by a dietary level of 2.5% fish meal or solubles. A level of 5% fish meal or solubles in the diet supplied about 0.1 p.p.m. total Se of which 16–29% was retained in the chick body in the first experiment and 15% in the second experiment. The retention value obtained in the second experiment, by supplying 0.1 p.p.m. Se from sodium selenite, was 35% and, therefore, in comparison the same levels of Se in fish meal or solubles was about 43% as effective as the standard. Compared to selenomethionine at the same level of Se, the fishery products were 31% as effective.

The relative contribution of acetate and glucose to aflatoxin biosynthesis

1. 1. Fungal secondary metabolites can be classified as acetate-derived or glucose-derived because of the permeability barrier formed by the mitochondrial membrane which separates CoASAc derived from acetate and from glucose. Simultaneous incorporation of acetate and glucose by parallel cultures of Aspergillus flavus shows that aflatoxins are acetate-derived metabolites and are probably synthesized extra-mitochondrially. 2. 2. High levels of exogenous acetate inhibit both glucose utilization and the incorporation of labels from glucose into aflatoxins.

Mechanisms of antifertility action of chlormadinone acetate in the rabbit.

Chlormadinone acetate was given orally in an aqueous vehicle to mature female rabbits, using a variety of dosage schedules, in a model ℌminipillℍ test. Two distinct mechanisms effective in preventing pregnancy were identified. At a dose level of 0.9 mg/kg/day, given for 3 or 4 days before artificial insemination and ovulation induction, fertilization of eggs was reduced to 12%. Continuation of the dosing for 8 days after ovulation did not alter the ED100. Acceleration of the rate of egg transport was observed whether progestin administration ceased before or after ovulation, indicating a direct effect of progestins upon the musculature of the reproductive tract. When similarly dosed animals were examined on the 15th day of pregnancy, complete inhibition of pregnancy was caused by 0.09 mg/kg/day. Investigation of the animals just prior to implantation revealed that the mechanism was compounded of accelerated egg transport, together with inhibition of blastocyst growth, shown by reduced egg recoveries and computation of blastocyst volumes, respectively. The results obtained are discussed as being analogous to the differing contraceptive mechanisms of high and low dose levels of chlormadinone acetate in the human. Comparisons are drawn between the ovulation-inhibiting action of high dose levels in human, and the fact that the high dose level used in this study (0.9 mg/kg/day) is above that needed for ovulation inhibition in the rabbit. Further similarities also exist between suboptimal ovulation inhibiting doses in the human (0.5 mg/kg/day) and in the rabbit (0.09 mg/kg/day), in that penetration of cervical mucus by spermatozoa is possible. It is suggested that inhibition of implantation may be implicated in the action of low doses of 17-acetoxy progestins in women.