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Nature Communications Jun 2020Aldehyde is one of most synthetically versatile functional groups and can participate in numerous chemical transformations. While a variety of simple aromatic aldehydes...
Aldehyde is one of most synthetically versatile functional groups and can participate in numerous chemical transformations. While a variety of simple aromatic aldehydes are commercially available, those with a more complex substitution pattern are often difficult to obtain. Benzylic oxygenation of methylarenes is a highly attractive method for aldehyde synthesis as the starting materials are easy to obtain and handle. However, regioselective oxidation of functionalized methylarenes, especially those that contain heterocyclic moieties, to aromatic aldehydes remains a significant challenge. Here we show an efficient electrochemical method that achieves site-selective electrooxidation of methyl benzoheterocycles to aromatic acetals without using chemical oxidants or transition-metal catalysts. The acetals can be converted to the corresponding aldehydes through hydrolysis in one-pot or in a separate step. The synthetic utility of our method is highlighted by its application to the efficient preparation of the antihypertensive drug telmisartan.
Topics: Acetals; Aldehydes; Amidines; Benzimidazoles; Catalysis; Electrochemical Techniques; Hydrocarbons, Aromatic; Hydrolysis; Models, Chemical; Molecular Structure; Oxidants; Oxidation-Reduction
PubMed: 32483217
DOI: 10.1038/s41467-020-16519-8 -
Applied Microbiology and Biotechnology Sep 2023Anaerobic, acetogenic bacteria are promising biocatalysts for a sustainable bioeconomy since they capture and convert carbon dioxide to acetic acid. Hydrogen is an...
Anaerobic, acetogenic bacteria are promising biocatalysts for a sustainable bioeconomy since they capture and convert carbon dioxide to acetic acid. Hydrogen is an intermediate in acetate formation from organic as well as C1 substrates. Here, we analyzed mutants of the model acetogen Acetobacterium woodii in which either one of the two hydrogenases or both together were genetically deleted. In resting cells of the double mutant, hydrogen formation from fructose was completely abolished and carbon was redirected largely to lactate. The lactate/fructose and lactate/acetate ratios were 1.24 and 2.76, respectively. We then tested for lactate formation from methyl groups (derived from glycine betaine) and carbon monoxide. Indeed, also under these conditions lactate and acetate were formed in equimolar amounts with a lactate/acetate ratio of 1.13. When the electron-bifurcating lactate dehydrogenase/ETF complex was genetically deleted, lactate formation was completely abolished. These experiments demonstrate the capability of A. woodii to produce lactate from fructose but also from promising C1 substrates, methyl groups and carbon monoxide. This adds an important milestone towards generation of a value chain leading from CO to value-added compounds. KEY POINTS: • Resting cells of the ΔhydBA/hdcr mutant of Acetobacterium woodii produced lactate from fructose or methyl groups + CO • Lactate formation from methyl groups + CO was completely abolished after deletion of lctBCD • Metabolic engineering of a homoacetogen to lactate formation gives a potential for industrial applications.
Topics: Fructose; Metabolic Engineering; Carbon Monoxide; Acetic Acid; Acetates; Lactates; Hydrogen; Carbon Dioxide
PubMed: 37417977
DOI: 10.1007/s00253-023-12637-7 -
PloS One Jun 2008Caenorhabditis elegans chemosensation has been successfully studied using behavioral assays that treat detection of volatile and water soluble chemicals as separate...
BACKGROUND
Caenorhabditis elegans chemosensation has been successfully studied using behavioral assays that treat detection of volatile and water soluble chemicals as separate senses, analogous to smell and taste. However, considerable ambiguity has been associated with the attractive properties of the compound ammonium-acetate (NH(4)Ac). NH(4)Ac has been used in behavioral assays both as a chemosensory neutral compound and as an attractant.
METHODOLOGY/MAIN FINDINGS
Here we show that over a range of concentrations NH(4)Ac can be detected both as a water soluble attractant and as an odorant, and that ammonia and acetic acid individually act as olfactory attractants. We use genetic analysis to show that NaCl and NH(4)Ac sensation are mediated by separate pathways and that ammonium sensation depends on the cyclic nucleotide gated ion channel TAX-2/TAX-4, but acetate sensation does not. Furthermore we show that sodium-acetate (NaAc) and ammonium-chloride (NH(4)Cl) are not detected as Na(+) and Cl(-) specific stimuli, respectively.
CONCLUSIONS/SIGNIFICANCE
These findings clarify the behavioral response of C. elegans to NH(4)Ac. The results should have an impact on the design and interpretation of chemosensory experiments studying detection and adaptation to soluble compounds in the nematode Caenorhabditis elegans.
Topics: Acetates; Animals; Behavior, Animal; Caenorhabditis elegans; Neurons; Olfactory Receptor Neurons; Taste
PubMed: 18560547
DOI: 10.1371/journal.pone.0002467 -
Journal of Lipid Research Jul 1968To investigate the mechanism by which ethanol lowers plasma free fatty acids, we tested the ability of two products of alcohol metabolism, acetate and lactate, to lower...
To investigate the mechanism by which ethanol lowers plasma free fatty acids, we tested the ability of two products of alcohol metabolism, acetate and lactate, to lower free fatty acids in man. Sodium acetate was given orally to five healthy fasting volunteers and caused a significant fall in plasma free fatty acids. After amounts of ethanol and acetate that produced similar reductions in free fatty acids, plasma acetate increased 3- to 4-fold within 20 min. In each of three subjects the fall of free fatty acids observed after acetate ingestion occurred at plasma acetate levels less than or equal to those reached after ethanol. In all studies plasma glucose remained stable. Oral administration of sodium lactate to another volunteer in amounts sufficient to raise plasma lactate concentrations to a level similar to that found after ethanol administration failed to lower plasma free fatty acids. Thus acetate, a metabolite of ethanol, reduces plasma free fatty acids at plasma acetate levels comparable to those resulting from ethanol metabolism, which suggests that the lowering of plasma free fatty acids produced by ethanol is mediated, at least in part, by acetate.
Topics: Acetates; Blood Glucose; Depression, Chemical; Ethanol; Fatty Acids, Nonesterified; Humans; Lactates; Male; Sodium; Time Factors
PubMed: 5725882
DOI: No ID Found -
Journal of Oleo Science 2020Microbial lipases are used for the synthesis of various short chain esters such as octyl acetate, methyl salicylate, ethyl acetate and ethyl lactate. In this study, a...
Microbial lipases are used for the synthesis of various short chain esters such as octyl acetate, methyl salicylate, ethyl acetate and ethyl lactate. In this study, a purified lipase of Aspergillus fumigatus was utilized for the synthesis of two esters i.e. ethyl acetate and ethyl lactate. The purified lipase from Aspergillus fumigatus performed esterification of ethanol and acetic acid (at a molar ratio of 1:1) when incubated at 40℃ under shaking (130 min) for 12 h resulting in the formation of ethyl acetate (89%). In case of ethyl lactate maximum esterification (87.32%) was achieved when ethanol and lactic acid (500:100 mM ) was used in heptane resulting in the synthesis of ethyl lactate at 40°C under shaking (120 rpm) after 12 h of reaction time. These esters of short chain carboxylic acid and alcohols belong to the highly important natural aroma compounds and are used as green solvents in food and pharmaceutical industry.
Topics: Acetates; Aspergillus fumigatus; Lactates; Lipase
PubMed: 31902892
DOI: 10.5650/jos.ess19202 -
Kidney International Jan 1992The mechanism of acetate vasorelaxation is unknown. In the rat caudal artery, acetate has a vasorelaxant effect and also increases cyclic AMP. Here we evaluate the role...
The mechanism of acetate vasorelaxation is unknown. In the rat caudal artery, acetate has a vasorelaxant effect and also increases cyclic AMP. Here we evaluate the role of adenosine, of possible glycolysis inhibition by acetate, of the lyotropic properties of acetate and other anions, and of intracellular calcium and pH. Adenosine per se did not relax the caudal artery in the range of 10(-8) to 10(-2) M. Preincubation with adenosine deaminase (ADA, 5.0 U/ml) or with 8-phenyltheophylline (8-PT, 10(-6) to 10(-4) M) increased, rather than blocked the vasorelaxant effect of acetate. Oxypurinol (10(-3) M) or the nucleoside transport inhibitor NBMPR (10(-4) M) had no effect on acetate relaxation. Whereas acetate increased tissue cyclic AMP content, 10(-3) M adenosine or 10(-6) M PIA had no effect. In strips studied under conditions of inhibited glycolysis (no glucose, with 11 mM 2-deoxyglucose, 1.0 mM pyruvate, and 0.5 mM 5-iodoacetate), acetate-induced relaxation, as well as acetate-induced cyclic AMP generation, tended to be reduced but not significantly so. Other anions relaxed vascular strips in relation to their lyotropic number, but only at higher doses, and they did not stimulate cyclic AMP formation. Acetate (10 mM) caused a transient fall in Ca2+i followed by a slight, sustained rise. A concomitant decrease in pHi was seen. DIDS, which blocks the relaxant and cyclic AMP effects of acetate, had no effect on the pHi decrease, but did decrease the rate of pHi recovery.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Acetates; Acetic Acid; Adenosine; Animals; Calcium; Cells, Cultured; Cyclic AMP; Glycolysis; Hydrogen-Ion Concentration; Male; Muscle, Smooth, Vascular; Rats; Solubility; Vasodilation
PubMed: 1317476
DOI: 10.1038/ki.1992.23 -
The Journal of General and Applied... Mar 2023Low-density polyethylene (LDPE) has been commercially used and accumulated as plastic solid waste. LDPE has also been found to be a non-degradable waste for decades and...
Low-density polyethylene (LDPE) has been commercially used and accumulated as plastic solid waste. LDPE has also been found to be a non-degradable waste for decades and found as a pollution source in the environment. In this study, 65 fungi were screened for their biodegradation of LDPE. The fungi Neopestalotiopsis phangngaensis, Alternaria burnsii, Alternaria pseudoeichhorniae, and Arthrinium sacchari showed significant potential in LDPE biodegradation. These fungi were individually cultured with an LDPE sheet as a carbon source for 90 days. A maximum weight loss of the LDPE sheet was detected by the fungus N. phangngaensis (54.34%). This fungus also revealed the highest reduction rate of tensile strength of the LDPE sheet (0.33 MPa). The morphological surface of LDPE culturing with N. phangngaensis was crack, pit, and rough analyzed by scanning electron microscopy. The biodegradation of the LDPE sheet by N. phangngaensis was also confirmed by the Sturm test and analysis of enzymatic activities. The Sturm test showed the highest decomposition of the LDPE sheet by N. phangngaensis into CO with 2.14 g/L after incubation. Enzymatic activities of laccase, manganese peroxidase, and lignin peroxidase enzymes were found by N. phangngaensis during the LDPE degradation. The volatile organic compounds in culture supernatant of N. phangngaensis were also investigated. The major compounds were 3Z-diethyl acetal hexenal, 2E,4E-decadienol, and 2Z-diethyl acetal hexenal. This study reveals the utilization of the fungus N. phangngaensis as the carbon source at a considerable biodegradation rate without any prior treatment. Therefore, the fungus N. phangngaensis may be applied as an alternative degrader for LDPE degradation in the environment.
Topics: Polyethylene; Acetals; Hexobarbital; Biodegradation, Environmental; Carbon
PubMed: 35922912
DOI: 10.2323/jgam.2022.07.001 -
Thorax Nov 1990Four hundred and ninety six smokers participated in a randomised comparison of the effect of silver acetate, nicotine, and ordinary chewing gum on smoking cessation. All... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
Four hundred and ninety six smokers participated in a randomised comparison of the effect of silver acetate, nicotine, and ordinary chewing gum on smoking cessation. All were motivated to stop smoking abruptly and all had smoked at least 10 cigarettes a day for at least five years. Side effects and taste acceptability were related to outcome after six months. The participants attended nine meetings over a year, at which lectures, support, and advice about stopping smoking were given. Tobacco abstinence was confirmed by measurement of carbon monoxide in expired air. The chewing gums were used for 12 weeks. After 12 weeks there was a trend towards more abstainers in the nicotine group (59%) than in the silver acetate (50%) and ordinary (45%) chewing gum groups that was not quite significant (p = 0.07). At 26 and 52 weeks the number of cigarette abstainers was similar in the three treatment groups. Subjects in the nicotine chewing gum group had a longer mean time before relapse than those in the silver acetate and ordinary chewing gum groups. Mean success rates for all subjects combined at 12, 26, and 52 weeks were 52.8%, 39.7%, and 23.3%. The side effects of nicotine and silver acetate chewing gum were generally mild and transient, and unimportant except for mouth irritation from silver acetate, which had a negative effect on outcome, and the low taste acceptability of nicotine, which had a strong negative influence on the success rate. The results suggest a short term effect on nicotine chewing gum on smoking cessation, but the abstinence rates after one year were generally disappointing.
Topics: Acetates; Acetic Acid; Adult; Chewing Gum; Counseling; Humans; Nicotine; Psychotherapy, Group; Smoking
PubMed: 2256009
DOI: 10.1136/thx.45.11.831 -
Journal of Dairy Science Jun 1984Entry rates of acetate and oleate and their incorporation into lipids of blood plasma and fatty acids of milk were studied in lactating goats fed a concentrate-roughage...
Entry rates of acetate and oleate and their incorporation into lipids of blood plasma and fatty acids of milk were studied in lactating goats fed a concentrate-roughage ration with propionic acid infused intraruminally at 0, 5.52, and 13.74 g/h by primed constant intravenous infusion of [1-carbon-14] acetate and [9, 10-hydrogen-3] oleate. Means for infusion rates were acetate, 60, 52, and 39 micrograms/ml blood plasma; propionate 9, 12, and 22 micrograms/ml; oleate, 19, 14, and 12 micrograms/ml; acetate entry rate, 3.9, 2.7, and 1.8 mmol/h per kg bodyweight; oleate entry rate, 47, 29, and 19 mumol/h per kg bodyweight; acetate oxidation rate, 2.0, 1.7, and 1.4 mmol/h per kg, and its contribution to the total carbon dioxide production, 16, 14, and 11%. Propionic acid increased incorporation of carbon-14 and hydrogen-3 into plasma lipids, elevated proportions of 7:0, 9:0, 11:0, 13:0, 15:0, and 17:0 fatty acids in milk, and tended to lower others. Specific radioactivities of milk fatty acids during infusion of propionic acid were elevated by 1.8 to 2.8 times, and total fatty acids in milk and plasma were lowered by 22 and 38%. Data support the glucogenic theory that propionic acid either directly or through gluconeogenesis stimulates insulin secretion, which in turn inhibits release of fatty acids from adipose tissue, resulting in milk fat depression.
Topics: Acetates; Acetic Acid; Animals; Fatty Acids; Fatty Acids, Volatile; Female; Goats; Lactation; Lipids; Milk; Oleic Acid; Oleic Acids; Pregnancy; Propionates
PubMed: 6747042
DOI: 10.3168/jds.S0022-0302(84)81424-1 -
Nanoscale Oct 2022Small interfering RNA (siRNA) is ideal for gene silencing through a sequence-specific RNA interference process. The redundancy and complexity of molecular pathways in...
Small interfering RNA (siRNA) is ideal for gene silencing through a sequence-specific RNA interference process. The redundancy and complexity of molecular pathways in cancer create a need for multiplexed targeting that can be achieved with multiplexed siRNA delivery. Here, we delivered multiplexed siRNA with a PSMA-targeted biocompatible dextran nanocarrier to downregulate CD46 and PD-L1 in PSMA expressing prostate cancer cells. The selected gene targets, PD-L1 and CD46, play important roles in the escape of cancer cells from immune surveillance. PSMA, abundantly expressed by prostate cancer cells, allowed the prostate cancer-specific delivery of the nanocarrier. The nanocarrier was modified with acid cleavable acetal bonds for a rapid release of siRNA. Cell imaging and flow cytometry studies confirmed the PSMA-specific delivery of CD46 and PD-L1 siRNA to high PSMA expressing PC-3 PIP cells. Immunoblot, qRT-PCR and flow cytometry methods confirmed the downregulation of CD46 and PD-L1 following treatment with multiplexed siRNA.
Topics: Acetals; B7-H1 Antigen; Cell Line, Tumor; Dextrans; Humans; Male; Prostatic Neoplasms; RNA, Double-Stranded; RNA, Small Interfering
PubMed: 36093754
DOI: 10.1039/d2nr02200a