Search results for "acetaldehyde"
showing 10 items of 90 documents
Ethanol cycle in an ethanologenic bacterium
2002
AbstractA novel redox cycle is suggested, performing interconversion between acetaldehyde and ethanol in aerobically growing ethanologenic bacterium Zymomonas mobilis. It is formed by the two alcohol dehydrogenase (ADH) isoenzymes simultaneously catalyzing opposite reactions. ADH I is catalyzing acetaldehyde reduction. The local reactant ratio at its active site probably is shifted towards ethanol synthesis due to direct channeling of NADH from glycolysis. ADH II is oxidizing ethanol. The net result of the cycle operation is NADH shuttling from glycolysis to the membrane respiratory chain, and ensuring flexible distribution of reducing equivalents between the ADH reaction and respiration.
EFFECT OF ACETALDEHYDE INTOXICATION AND WITHDRAWAL ON NEUROPEPTIDE Y EXPRESSION. FOCUS ON CB1 RECEPTOR ROLE.
2014
Neuropeptide Y (NPY) acts as an endogenous anxiolytic, and, like endocannabinoids, plays an important role in the regulation of neuronal excitability during ethanol withdrawal (Rubio et al., 2011). Since acetaldehyde is considered a mediator of ethanol central effects, this research aims at investigating, following intoxication and during withdrawal, the effects of acetaldehyde on NPY expression in brain areas particularly vulnerable to alcohol, and the influence of cannabinoid system on it. Rats underwent acetaldehyde intoxication (450mg/kg, i.g., 4 times daily for 4 days); AM281, a CB1 selective antagonist (2,5 mg/kg, i.p.) was administered during abstinence. Immunohistochemical analysis …
Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions
2012
Abstract Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercet…
Syntheses with organoboranes. Part 14: Enolization–aldolization of conjugated cyclohexenones via dienolborinates
2002
Abstract Enolization of cyclohex-2-enone ( 1 ), 3-methyl- ( 2 ), 3,5-dimethyl- ( 3 ), 3,5,5-trimethyl- ( 4 ), and 3,4,5,5-tetramethylcyclohex-2-enone ( 5 ) with chlorodicyclohexylborane proceeds by deprotonation at the 6-position. Aldolization of the dienolborinates with benzaldehyde, and acetaldehyde, provides the corresponding anti aldols with 87–95% selectivity. Ketones 4 and 5 undergo competitive deprotonation at the 3-methyl group and aldolization at the 2-position. In contrast, lithium dienolates derived from 4 and 5 gave syn aldols with 95% selectivity.
Disposition ofd-penicillamine, a promising drug for preventing alcohol-relapse. Influence of dose, chronic alcohol consumption and age: studies in ra…
2014
Pharmacokinetic studies concerning d-penicillamine (an acetaldehyde sequestering agent) are scarce and have not evaluated the influence of chronic ethanol consumption and age on its disposition. Since recent preclinical studies propose d-penicillamine as a promising treatment for alcohol relapse, the main aim of the present work was to evaluate the influence of these two factors on d-penicillamine disposition in order to guide future clinical studies on the anti-relapse efficacy of this drug in alcoholism. Additionally, the effect of the administered dose was also evaluated. To this end, three studies were carried out. Study 1 assessed the influence of dose on d-penicillamine disposition, w…
Universal Concept for the Implementation of a Single Cleavable Unit at Tunable Position in Functional Poly(ethylene glycol)s
2013
Poly(ethylene glycol) (PEG) with acid-sensitive moieties gained attention particularly for various biomedical applications, such as the covalent attachment of PEG (PEGylation) to protein therapeutics, the synthesis of stealth liposomes, and polymeric carriers for low-molecular-weight drugs. Cleavable PEGs are favored over their inert analogues because of superior pharmacodynamic and/or pharmacokinetic properties of their formulations. However, synthetic routes to acetal-containing PEGs published up to date either require enormous efforts or result in ill-defined materials with a lack of control over the molecular weight. Herein, we describe a novel methodology to implement a single acetalde…
Acetaldehyde, motivation and stress: Behavioral evidence of an addictive ménage à trois
2017
Acetaldehyde contributes to alcohol’s psychoactive effects through its own rewarding properties. Recent studies shed light on the behavioral correlates of acetaldehyde administration and the possible interactions with key neurotransmitters for motivation, reward and stress-related response, such as dopamine and endocannabinoids. This mini review critically examines acetaldehyde psychoactive properties, focusing on behavioral investigations able to unveil acetaldehyde motivational effects and their pharmacological modulation in vivo. Similarly to alcohol, rats spontaneously drink acetaldehyde, whose presence is detected in the brain following chronic self-administration paradigm. Acetaldehyd…
Translocation of Zymomonas mobilis pyruvate decarboxylase to periplasmic compartment for production of acetaldehyde outside the cytosol
2019
Abstract Acetaldehyde, a valuable commodity chemical, is a volatile inhibitory byproduct of aerobic fermentation in Zymomonas mobilis and in several other microorganisms. Attempting to improve acetaldehyde production by minimizing its contact with the cell interior and facilitating its removal from the culture, we engineered a Z. mobilis strain with acetaldehyde synthesis reaction localized in periplasm. For that, the pyruvate decarboxylase (PDC) was transferred from the cell interior to the periplasmic compartment. This was achieved by the construction of a Z. mobilis Zm6 PDC‐deficient mutant, fusion of PDC with the periplasmic signal sequence of Z. mobilis gluconolactonase, and the follow…
NADH dehydrogenase deficiency results in low respiration rate and improved aerobic growth of Zymomonas mobilis.
2008
The respiratory chain of the ethanol-producing bacterium Zymomonas mobilis is able to oxidize both species of nicotinamide cofactors, NADH and NADPH. A mutant strain with a chloramphenicol-resistance determinant inserted in ndh (encoding an NADH : CoQ oxidoreductase of type II) lacked the membrane NADH and NADPH oxidase activities, while its respiratory d-lactate oxidase activity was increased. Cells of the mutant strain showed a very low respiration rate with glucose and no respiration with ethanol. The aerobic growth rate of the mutant was elevated; exponential growth persisted longer, resulting in higher biomass densities. For the parent strain a similar effect of aerobic growth stimulat…
Dopamine involvement in Acetaldehyde drinking behaviour: role of Ropinirole on.
2013
Rats self-administer acetaldehyde(ACD), ethanol's first metabolite, directly into cerebral ventricles (1), and multiple ICV infusions of ACD produce conditioned place preference (2). ACD, such as alcohol and other substances of abuse, interacts with dopaminergic reward system (3) and its reinforcing and addictive properties have been assessed through an operant-conflict conditioning procedure (4). Since dopamine D2receptor over-expression in the Nacc attenuates alcohol intake (5), this study aims at exploring the effects of ropinirole administration during abstinence, on ACD relapse. The protocol has been scheduled into 3 different periods: training ( animals have been trained to self-admin…