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PubMed2005

Acetate excretion during growth of Salmonella enterica on ethanolamine requires phosphotransacetylase (EutD) activity, and acetate recapture requires acetyl-CoA synthetase (Acs) and phosphotransacetylase (Pta) activities.

This report shows that Salmonella enterica catabolizes ethanolamine to acetyl-CoA (Ac-CoA), which enters the glyoxylate bypass and tricarboxylic acid cycle for the generation of energy and central metabolites. During growth on ethanolamine, S. enterica excreted acetate, whose recapture depended on Ac-CoA synthetase (Acs) and the housekeeping phosphotransacetylase (Pta) enzyme activities. The Pta enzyme did not play a role in acetate excretion during growth of S. enterica on ethanolamine. It is proposed that during growth on ethanolamine, acetate excretion is necessary to maintain a pool of free CoA. Acetate excretion requires the eut operon-encoded phosphotransacetylase (EutD) and acetate kinase (Ack) enzymes. EutD function was not required for growth on ethanolamine, and an eutD strain showed only a slight reduction in growth rate. The existence of an as-yet-unidentified system that releases acetate was revealed during growth of a strain lacking Acs, the housekeeping phosphotransacetylase (Pta), and EutD. The functions of pyruvate oxidase (PoxB), Ack and STM3118 protein [a homologue of the Saccharomyces cerevisiae Ac-CoA hydrolase (Ach1p) enzyme] were not involved in the release of acetate by the acs pta eutD strain.

Acetate-CoA Ligase↗

PubMed1990

Comparison of growth, acetate production, and acetate inhibition of Escherichia coli strains in batch and fed-batch fermentations.

The growth characteristics and acetate production of several Escherichia coli strains were compared by using shake flasks, batch fermentations, and glucose-feedback-controlled fed-batch fermentations to assess the potential of each strain to grow at high cell densities. Of the E. coli strains tested, including JM105, B, W3110, W3100, HB101, DH1, CSH50, MC1060, JRG1046, and JRG1061, strains JM105 and B were found to have the greatest relative biomass accumulation, strain MC1060 accumulated the highest concentrations of acetic acid, and strain B had the highest growth rates under the conditions tested. In glucose-feedback-controlled fed-batch fermentations, strains B and JM105 produced only 2 g of acetate.liter-1 while accumulating up to 30 g of biomass.liter-1. Under identical conditions, strains HB101 and MC1060 accumulated less than 10 g of biomass.liter-1 and strain MC1060 produced 8 g of acetate.liter-1. The addition of various concentrations of sodium acetate to the growth medium resulted in a logarithmic decrease, with respect to acetate concentration, in the growth rates of E. coli JM105, JM105(pOS4201), and JRG1061. These data indicated that the growth of the E. coli strains was likely to be inhibited by the acetate they produced when grown on media containing glucose. A model for the inhibition of growth of E. coli by acetate was derived from these experiments to explain the inhibition of acetate on E. coli strains at neutral pH.

Acetates↗

PubMed1984

Inhibition by magnesium and calcium acetates of lead subacetate- and nickel acetate-induced lung tumors in strain A mice.

The ability of the physiologically essential divalent metals calcium and magnesium to inhibit the tumorigenic activities of lead and nickel towards the lungs of strain A mice was investigated. The tumorigenic salts lead(II) subacetate and nickel(II) acetate were injected i.p. at their maximal tolerated doses (0.04 mmol/kg/injection of each metal) for a total of 24 injections, whenever possible. Calcium(II) acetate and magnesium(II) acetate were administered in the same preparation along with the lead and nickel salts at molar doses of approximately 1, 3, 10, and 30 times the maximal tolerated dose of the tumorigen. The animals were sacrificed 30 weeks after the first injection, and the lung tumors were counted. The lead and nickel salts, administered alone, each produced a significant increase in the observed number of lung adenomas per mouse. When administered with any of the doses of calcium acetate or magnesium acetate tested, neither lead subacetate nor nickel acetate showed any significant tumorigenic activity. Calcium acetate alone (total dose, 11 mmol/kg of body weight) appeared to yield a significant rise in lung adenomas observed. The results indicate an antagonism between magnesium and calcium and the tumorigenic metals nickel and lead.

Acetates↗

PubMedDate not supplied

The acetic acid component of lead acetate: its effect on rat weight and activity.

Suckling rats were exposed to one of three solutions, 2.6 x 10(-3) M lead acetate, 5 x 10(-3) M acetic acid or water, from parturition until the pups were 18 days old. Male offspring from dams on acetic acid demonstrated above normal preweaning body weights and were significantly less active than normals in the open field by day 44. The preweaning body weights and ambulation of offspring from dams on lead acetate fell between the results for normal and acetic acid rats. These results indicate that the role of the acetic acid component cannot be discounted when lead acetate is the compound utilized in behavioral studies aimed at examining an effect by lead on laboratory rats.

Acetates↗

PubMed2001

Characterization of acetate metabolism in tumor cells in relation to cell proliferation: acetate metabolism in tumor cells.

To reveal the metabolic fate of acetate in neoplasms that may characterize the accumulation patterns of [1-(11)C]acetate in tumors depicted by positron emission tomography. Four tumor cell lines (LS174T, RPMI2650, A2780, and A375) and fibroblasts in growing and resting states were used. In uptake experiments, cells were incubated with[1-(14)C]acetate for 40 min. [(14)C]CO(2) was measured in the tight-air chamber, and the metabolites in cells were identified by thin layer chromatography and paper chromatography. The glucose metabolic rate of each cell line was measured with [2,6-(3)H]2-deoxy-glucose (DG), and the growth activity of each cell line was estimated by measuring the incorporation of [(3)H]methyl thymidine into DNA. Compared with resting fibroblasts, all four tumor cell lines showed higher accumulation of (14)C activity from [1-(14)C]acetate. These tumor-to-normal ratios of [1-(14)C]acetate were larger than those of DG. Tumor cells incorporated (14)C activity into the lipid-soluble fraction, mostly of phosphatidylcholine and neutral lipids, more prominently than did fibroblasts. The lipid-soluble fraction of (14)C accumulation in cells showed a positive correlation with growth activity, whereas the water-soluble and CO(2) fractions did not. These findings suggest that the high tumor-to-normal ratio of [1-(14)C]acetate is mainly due to the enhanced lipid synthesis, which reflects the high growth activity of neoplasms. This in vitro study suggests that [1-(11)C]acetate is appropriate for estimating the growth activity of tumor cells.

Acetates↗

PubMed1998

Trypanosomatidae produce acetate via a mitochondrial acetate:succinate CoA transferase.

Hydrogenosome-containing anaerobic protists, such as the trichomonads, produce large amounts of acetate by an acetate:succinate CoA transferase (ASCT)/succinyl CoA synthetase cycle. The notion that mitochondria and hydrogenosomes may have originated from the same alpha-proteobacterial endosymbiont has led us to look for the presence of a similar metabolic pathway in trypanosomatids because these are the earliest-branching mitochondriate eukaryotes and because they also are known to produce acetate. The mechanism of acetate production in these organisms, however, has remained unknown. Four different members of the trypanosomatid family: promastigotes of Leishmania mexicana mexicana, L. infantum and Phytomonas sp., and procyclics of Trypanosoma brucei were analyzed as well as the parasitic helminth Fasciola hepatica. They all use a mitochondrial ASCT for the production of acetate from acetyl CoA. The succinyl CoA that is produced during acetate formation by ASCT is recycled presumably to succinate by a mitochondrial succinyl CoA synthetase, concomitantly producing ATP from ADP. The ASCT of L. mexicana mexicana promastigotes was further characterized after partial purification of the enzyme. It has a high affinity for acetyl CoA (Km 0.26 mM) and a low affinity for succinate (Km 6.9 mM), which shows that significant acetate production can occur only when high mitochondrial succinate concentrations prevail. This study identifies a metabolic pathway common to mitochondria and hydrogenosomes, which strongly supports a common origin for these two organelles.

Acetates↗

PubMed2003

Fecal acetate is inversely related to acetate absorption from the human rectum and distal colon.

In humans, colonic bacteria ferment unabsorbed carbohydrates, producing the SCFA acetic, propionic and n-butyric acids. To test for interactions among the SCFA that may affect their absorption, healthy subjects (n = 10) were given 300-mL rectal infusions containing acetate (60 mmol/L), propionate (20 mmol/L) and butyrate (20 mmol/L), alone or in combinations of two or three. The solutions were retained for 30 min, and then subjects voided a sample for SCFA measurement. To examine the relationship between absorption and fecal SCFA concentrations, a fecal sample was collected at the end of the study. The mean percentage of butyrate absorption (30.2 +/- 4.6%) exceeded that of acetate (24.1 +/- 3.7%) (P < 0.05). Absorption tended to be less (P = 0.12) when a SCFA was infused alone (26.7 +/- 4.0%) than when all three were infused (32.0 +/- 5.7%). Bicarbonate concentration was higher after butyrate-containing infusions than after saline. The fecal molar acetate percentage was inversely correlated with the percentage of acetate absorption from the infusion of three SCFA (r = -0.834, P < 0.005). We conclude that there was no combination effect on SCFA absorption, and the chain-length effect suggests passive diffusion as a likely mechanism of absorption. Furthermore, fecal acetate may reflect absorption, rather than production of colonic acetate.

Acetic Acid↗

PubMed2002

Acetate utilization and butyryl coenzyme A (CoA):acetate-CoA transferase in butyrate-producing bacteria from the human large intestine.

Seven strains of Roseburia sp., Faecalibacterium prausnitzii, and Coprococcus sp. from the human gut that produce high levels of butyric acid in vitro were studied with respect to key butyrate pathway enzymes and fermentation patterns. Strains of Roseburia sp. and F. prausnitzii possessed butyryl coenzyme A (CoA):acetate-CoA transferase and acetate kinase activities, but butyrate kinase activity was not detectable either in growing or in stationary-phase cultures. Although unable to use acetate as a sole source of energy, these strains showed net utilization of acetate during growth on glucose. In contrast, Coprococcus sp. strain L2-50 is a net producer of acetate and possessed detectable butyrate kinase, acetate kinase, and butyryl-CoA:acetate-CoA transferase activities. These results demonstrate that different functionally distinct groups of butyrate-producing bacteria are present in the human large intestine.

Acetates↗

PubMedDate not supplied

[The mechanism of acetate assimilation in purple nonsulfur bacteria lacking the glyoxylate pathway: acetate assimilation in Rhodobacter sphaeroides cells].

The mechanism of acetate assimilation in the purple nonsulfur bacterium Rhodobacter sphaeroides, which lacks the glyoxylate pathway, is studied. It is found that the growth of this bacterium in batch and continuous cultures and the assimilation of acetate in cell suspensions are not stimulated by bicarbonate. The consumption of acetate is accompanied by the excretion of glyoxylate and pyruvate into the medium, stimulated by glyoxylate and pyruvate, and inhibited by citramalate. The respiration of cells in the presence of acetate is stimulated by glyoxylate, pyruvate, citramalate, and mesaconate. These data suggest that the citramalate cycle may function in Rba. sphaeroides in the form of an anaplerotic pathway instead of the glyoxylate pathway. At the same time, the low ratio of fixation rates for bicarbonate and acetate exhibited by the Rba. sphaeroides cells (approximately 0.1), as well as the absence of the stimulatory effect of acetate on the fixation of bicarbonate in the presence of the Calvin cycle inhibitor iodoacetate, suggests that pyruvate synthase is not involved in acetate assimilation in the bacterium Rba. sphaeroides.

Acetates↗

PubMed1984

[Plasma acetate and bicarbonate kinetics and intolerance to acetate during and after renal dialysis].

Plasma acetate kinetics, acid-base homeostasis and clinical tolerance were monitored in 7 patients with chronic renal failure during and after hemodialysis with standard conditions. In 6 patients, without severe clinical symptoms acetate levels became stable during the last hour of dialysis (4.86 +/- 0.44 mmol/l) and decreased according to first order kinetics (half-life (8.82 +/- 3.42 mn). Simultaneously bicarbonate levels significantly increased (p less than 0.005). At the opposite the 7th patient has been characterised by a continuous rise in acetate levels (12.3 mmol/l at the end of the dialysis), a slower elimination (half-life: 31.0 mn), a collapse of plasma bicarbonate and severe acetate intolerance. Moreover symptomatic patients were characterised by an increase of plasma levels and half-lives. Therefore it seems that during dialysis of comparable efficiency, an insufficient rate of acetate metabolism may be at the origin of a worsening of metabolic acidosis as well as an increase of acetate load, responsible for severe acetate intolerance.

Acetates↗

PubMed2004

Vinyl acetate formation by the reaction of ethylene with acetate species on oxygen-covered Pd(111).

The reaction pathway of vinyl acetate synthesis is scrutinized by reacting gas-phase ethylene (at an effective pressure of 1 x 10-4 Torr) with eta2-acetate species (with a coverage of 0.31 +/- 0.02 monolayer) on a Pd(111)-O(2x2) model catalyst surface in ultrahigh vacuum. It is found that the 1414 cm-1 infrared feature due to the symmetric OCO stretching mode of the acetate species decreases in intensity due to reaction with gas-phase ethylene, while temperature-programmed desorption experiments demonstrate that vinyl acetate is formed. The formation of ethylidyne species is detected when almost all of the acetate species have been removed. The experimental removal kinetics are reproduced by a model in which adsorbed acetates react with an ethylene-derived (possibly ethylene or vinyl) species, where ethylene adsorption is blocked by the acetate present on the surface.

Journal Article↗

PubMed2006

Reaction of the acetals with TESOTf-base combination; speculation of the intermediates and efficient mixed acetal formation.

We report here unexpected highly chemoselective deprotection of the acetals from aldehydes. Treatment of acetal compounds from aldehydes with TESOTf-2,6-lutidine or TESOTf-2,4,6-collidine in CH2Cl2 at 0 degrees C followed by H2O workup at the same temperature caused the conversion of the acetal functions to aldehyde functions. The reaction had generality and was applied to many acetal compounds. Study using various bases revealed the reaction and reached the best combination of TESOTf-base. It was very mild and highly chemoselective and proceeded under weakly basic conditions. Then, many functional groups such as allyl alcohol, silyl ether, acetate, methyl ether, triphenylmethyl (Tr) ether, 1,3-dithiolane, methyl ester, and tert-butyl ester could survive under these conditions. Furthermore, this methodology could selectively deprotect the acetals in the presence of ketals as the most characteristic feature, although this chemoselectivity is difficult to achieve by other previously reported methods. A detailed study of the reaction including MS and NMR studies revealed the reaction mechanism for determining the structures of the intermediates, pyridinium-type salts. These intermediates had a weak electrophilicity and were successfully applied to the efficient formation of the mixed acetals in high yields.

Journal Article↗

PubMed1997

Sequential danazol/leuprolide acetate therapy for ovarian suppression in an in vitro fertilization patient unresponsive to leuprolide acetate.

We report a case of pituitary-ovarian suppression obtained with sequential danazol/leuprolide acetate administration in a patient undergoing in vitro fertilization and unresponsive to leuprolide acetate alone and sequential oral contraceptive-leuprolide acetate therapy. Leuprolide acetate (1 mg daily subcutaneously) was administered after 5 weeks of danazol treatment (800 mg daily) while the latter was maintained for 1 additional week. Ovarian activity was assessed by transvaginal ultrasonography and serum estradiol determination. After 5 weeks of danazol therapy, ovarian arrest was obtained despite the fact that gonadotropin serum levels did not change relative to basal values. Leuprolide acetate injection for 14 days was associated with a decrease in serum concentrations of follicle-stimulating hormone and luteinizing hormone and a further decrease of the estradiol level. We conclude that sequential danazol/leuprolide acetate therapy is a useful alternative for obtaining ovarian arrest in patients unresponsive to leuprolide acetate alone.

Adult↗

PubMed1980

Enhancement by lead acetate of body weight-decreasing activity of endotoxin: quantitative comparisons of some administration methods of lead acetate.

The body weight-decreasing effect of sublethal doses of endotoxin was enhanced in mice administered with such an amount of lead acetate that had no effect by itself on body weight. The enhancing effects of administration of lead acetate prior to, simultaneously with and after endotoxin administration were analyzed and compared by statistical methods. Linear dose-response relation between logarithmic doses of endotoxin and body weight-decreasing responses was obtained over a wide range of endotoxin doses with a constant dose of lead acetate. The non-parallelism between two dose-response lines obtained in lead acetate-treated and control mice was not denied. The relation of the two lines indicated that the more minute the dose of endotoxin, the more intense the enhancing effect of lead acetate appearing in the treated mice within certain limits of minute doses of endotoxin. These results were common in the three administration methods of lead acetate and can be applied to detection of minute doses of endotoxin. It was suggested that the pre-administration method of lead acetate was more suitable for detection of endotoxin than the other methods.

Animals↗

PubMed2006

Acetyl-CoA synthetase overexpression in Escherichia coli demonstrates more efficient acetate assimilation and lower acetate accumulation: a potential tool in metabolic engineering.

The overexpression of acetyl-CoA (CoA) synthetase (ACS) in Escherichia coli showed significant reduction in acetate during glucose fermentation. It also greatly enhanced acetate assimilation when acetate was used as a carbon source. These features are ideal for applications in metabolic engineering. ACS overexpression can be strategically applied to reduce acetate byproduct, recover wasted carbon, and redirect carbon flux toward more favorable pathways. The native acs gene was cloned and overexpressed in E. coli. Studies showed significant effects on acetate production and assimilation in cultures grown in minimal and complex media with glucose or acetate as the carbon source.

Acetate-CoA Ligase↗

PubMed1976

[Liver function tests under the influence of sequential treatment using ethinyl estradiol-norethisterone acetate and ethinyl estradiol-chlormadinone acetate].

30 young healthy women were investigated during the first therapy cycle with ethinyl-estradiol-norethisterone acetate and ethinyl-estradiol-chlormadinone acetate as a sequential regime. The following laboratory data were achieved by each of the investigated group of young women: serum aminotransferase (GOT and GPT), serum alkaline phosphatase and alpha-amylase-activity in serum, serum proteins, serum cholesterol, serum bilirubin, serum ZST, serum TTT and the indocyaningreen-clearance of the liver. The serum protein pattern was determined by the paper electrophoretic method. A significant decrease of the aminotransferase GPT was viable during the sequential therapy with ethinyl-estradiol and norethisterone acetate. This viable decrease of the GPT was induced through the application of norethisterone acetate to estrogen. The alkaline phosphatase was significant lightly lower and the beta-globuline lightly elevated at the end of the therapy cycle. The sequential therapy with ethinyl-estradiol and chlormadinone acetate induced only a significant increase of the ZST in serum.

Adolescent↗

PubMed2004

Persistent retention of acetic acid is associated with complete tumour necrosis in patients with hepatocellular carcinoma undergoing percutaneous acetic acid injection.

BACKGROUND: Ultrasound (US)-guided percutaneous acetic acid injection therapy (PAIT) is effective for patients with hepatocellular carcinoma (HCC). This study aimed to determine the occurrence and predictive value of persistent intra-tumoral retention of acetic acid after PAIT. METHODS: We prospectively studied 60 (52 M, mean age 68 +/- 10 years) patients with 72 HCC nodules (45 < or = 3 cm) treated with PAIT. The presence of post-treatment persistent retention of acetic acid, defined as a homogeneous and highly hyperechoid mass in US appearance 3 days after completion of the treatment, was correlated with the treatment response. RESULTS: The mean size of the treated tumour was 2.9 +/- 1.0 cm (range 1.5-5 cm). Thirty (42%) HCC nodules showed complete tumour necrosis demonstrated by contrast-enhanced dynamic CT. Complete response was found in 22 (69%) of 32 nodules showing persistent intra-tumoral retention of acetic acid (P < 0.001). Small (< or = 3 cm) tumour size was also significantly associated with complete tumour necrosis (P = 0.001). There were no significant differences of the injection volume and treatment sessions between those with and without complete tumour necrosis in either small or large (> 3 cm) HCC (P > 0.1). Multivariate logistic regression analysis showed that persistent retention of acetic acid (odds ratio (OR) 10.4, 95% confidence interval (CI) 3.1-34.7; P < 0.001) and tumour size < or = 3 cm (OR 6.8, 95%, CI 1.8-25.8; P = 0.002) were independent factors predicting complete tumour necrosis. CONCLUSIONS: The presence of persistent retention of acetic acid is associated with a favourable response and may predict complete tumour necrosis after PAIT.

Acetic Acid↗

PubMed1989

X-ray studies on crystalline complexes involving amino acids and peptides. Part XX. Crystal structures of DL-arginine acetate monohydrate and DL-lysine acetate and a comparison with the corresponding L-amino acid complexes.

Crystals of DL-arginine acetate monohydrate, C6H15N4O2+C2H3O2-.H2O, are monoclinic, P2(1)/c, with a = 13.552(2), b = 5.048(2), c = 18.837(3) A, beta = 101.34(2) degrees and Z = 4, and those of DL-lysine acetate, C6H15N2O2+.C2H3O2- are triclinic, P1, with a = 5.471(2), b = 7.656(2), c = 12.841(2) A, alpha = 94.48(1), beta = 94.59(2), gamma = 98.83(2) degrees and Z = 2. The structures have been solved by direct methods and refined to R = 0.058 and 0.077 for 1522 and 1259 observed reflections respectively. The difference in the number and the nature of proton donors leads to a difference in hydrogen bond density in the two structures. The basic elements of aggregation in both the structures are pairs of amino acid molecules, each pair stabilized by two centrosymmetrically related hydrogen bonds involving alpha-amino and alpha-carboxylate groups, stacked along the shortest dimension to form columns. The pairs are held together in each column by head-to-tail sequences. The columns stack along a crystallographic axis to form layers. Adjacent layers are bridged by acetate ions. The amino acid-acetate interactions are primarily through side chains and involve specific interactions and characteristic interaction patterns. The gross features of molecular aggregation are nearly the same in DL-arginine acetate monohydrate and L-arginine acetate whereas they are substantially different in the lysine complexes. In both cases, one of the two head-to-tail sequences in the L complex is replaced by a hydrogen bonded loop involving alpha-amino and alpha-carboxylate groups, in the DL complex. This may have implications for prebiotic condensation during chemical evolution.

Acetates↗