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MLife Jun 2024is a hyperthermophilic crenarchaeon that produces 1-butanol as an end product. A thermostable alcohol dehydrogenase (ADH) must be present in to act as the key enzyme...
is a hyperthermophilic crenarchaeon that produces 1-butanol as an end product. A thermostable alcohol dehydrogenase (ADH) must be present in to act as the key enzyme responsible for this production; however, the gene that encodes the ADH has not yet been identified. A novel ADH, HbADH2, was purified from a cell-free extract of , and its characteristics were determined. The gene that encodes HbADH2 was demonstrated to be and annotated as a hypothetical protein in . HbADH2 was found to be a primary-secondary ADH capable of using a wide range of substrates, including butyraldehyde and butanol. Butyraldehyde had the highest specificity constant, calculated as / , with and apparent values of 8.00 ± 0.22 s and 0.59 ± 0.07 mM, respectively. The apparent values for other substrates, including ethanol, 1-propanol, 2-propanol, butanol, acetaldehyde, propanal, and acetone, were 4.36 ± 0.42, 4.69 ± 0.41, 3.74 ± 0.46, 2.44 ± 0.30, 1.27 ± 0.18, 1.55 ± 0.20, and 0.68 ± 0.04 mM, respectively. The optimal pH values for catalyzing aldehyde reduction and alcohol oxidation were 6.0 and 9.0, respectively, while the optimal temperature was higher than 90°C due to the increase in enzymatic activity from 60°C to 90°C. Based on its substrate specificity, enzyme kinetics, and thermostability, HbADH2 may be the ADH that catalyzes the production of 1-butanol in . The putative conserved motif sites for NAD(P) and iron binding were identified by aligning HbADH2 with previously characterized Fe-containing ADHs.
PubMed: 38948144
DOI: 10.1002/mlf2.12126 -
Journal of Dairy Science Jun 2024Yogurt is popular as a natural and healthy food, but its flavor greatly affects acceptability by consumers. Flavor compounds of yogurt is generally produced by the... (Review)
Review
Yogurt is popular as a natural and healthy food, but its flavor greatly affects acceptability by consumers. Flavor compounds of yogurt is generally produced by the metabolism of lactose, protein and fat, and the resulting flavors include carbonyls, acids, esters and alcohols, etc. Each flavor compounds could individually provide the corresponding flavor, or it can be combined with other compounds to form a new flavor. The flavor network was formed among the metabolites of milk components, and acetaldehyde, as the central compounds, played a role in connecting the whole network. The flavor compounds can be affected by many factors, such as the use of different raw milks, ways of homogenization, sterilization, fermentation, post ripening, storage condition and packaging materials, etc., which can affect the overall flavor of yogurt. This paper provides an overview of the volatile flavor compounds in yogurt, the pathways of production of the main flavor compounds during yogurt fermentation, and the factors that influence the flavor of yogurt including type of raw milk, processing, and storage. It also tries to provide theoretical guidance for the product of yogurt in ideal flavor, but further research is needed to provide a more comprehensive description of the flavor system of yogurt.
PubMed: 38945263
DOI: 10.3168/jds.2024-24875 -
Mutation Research Jun 2024Reactive aldehydes, for instance, formaldehyde and acetaldehyde, are important endogenous or environmental mutagens by virtue of their abilities to produce a DNA lesion... (Review)
Review
Reactive aldehydes, for instance, formaldehyde and acetaldehyde, are important endogenous or environmental mutagens by virtue of their abilities to produce a DNA lesion called interstrand crosslink (ICL). Aldehyde-metabolizing enzymes such as aldehyde dehydrogenases (ALDHs) and the Fanconi anemia (FA) pathway constitute the main defense lines against aldehyde-induced genotoxicity. Biallelic mutations of genes in any one of the FA complementation groups can impair the ICL repair mechanism and cause FA, a heterogeneous disorder manifested by bone marrow failure (BMF), congenital abnormality and a strong predisposition to cancer. The defective ALDH2 polymorphism rs671 (ALDH2*2) is a known risk and prognostic factor for alcohol drinking-associated cancers. Recent studies suggest that it also promotes BMF and cancer development in FA, and its combination with alcohol dehydrogenase 5 (ADH5) mutations causes aldehyde degradation deficiency syndrome (ADDS), also known by its symptoms as aplastic anemia, mental retardation, and dwarfism syndrome. ALDH2*2 and another pathogenic variant in the alcohol-metabolizing pathway, ADH1B1*1, is prevalent among East Asians. Also, other ALDH2 genotypes with disease-modifying potentials have lately been identified in different populations. Therefore, it would be appropriate to summarize current knowledge of genotoxic aldehydes and defense mechanisms against them to shed new light on the pathogenic effects of ALDH2 variants together with other genetic and environmental modifiers on cancer and inherited BMF syndromes. Lastly, we also presented potential treatment strategies for FA, ADDS and cancer based on the manipulation of aldehyde-induced genotoxicity.
PubMed: 38944932
DOI: 10.1016/j.mrfmmm.2024.111870 -
Molecules (Basel, Switzerland) Jun 2024Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum...
Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum allowed copper (II) ion doses in wine grapes at harvest can have on aged wine quality. This was the focus of the present study. We investigated the copper (II) effects by producing both white and red wines from musts containing three initial metal concentrations according to the limits set for organic farming. In detail, the influence of copper (II) on fermentation evolution, chromatic characteristics, and phenolic compounds was evaluated. Interestingly, the white wine obtained with the highest permitted copper (II) dose initially exceeded the concentration of 1.0 mg/L at fermentation completion. However, after one year of storage, the copper (II) content fell below 0.2 ± 0.01 mg/L. Conversely, red wines showed copper (II) levels below 1.0 mg/L at the end of fermentation, but the initial copper (II) level in musts significantly affected total native anthocyanins, color intensity, hue, and acetaldehyde concentration. After 12-month aging, significant differences were observed in polymeric pigments, thus suggesting a potential long-term effect of copper (II) on red wine color stability.
Topics: Wine; Copper; Acetaldehyde; Phenols; Fermentation; Vitis; Color; Anthocyanins
PubMed: 38930972
DOI: 10.3390/molecules29122907 -
Critical Reviews in Microbiology Jun 2024stands as the foremost prevalent human commensal pathogen and a significant contributor to nosocomial fungal infections. In the metabolism of , alcohol dehydrogenase 1... (Review)
Review
stands as the foremost prevalent human commensal pathogen and a significant contributor to nosocomial fungal infections. In the metabolism of , alcohol dehydrogenase 1 (Adh1) is one of the important enzymes that converts acetaldehyde produced by pyruvate decarboxylation into ethanol at the end of glycolysis. Leveraging the foundational processes of alcoholic fermentation, Adh1 plays an active role in multiple biological phenomena, including biofilm formation, interactions between different species, the development of drug resistance, and the potential initiation of gastrointestinal cancer. Additionally, Adh1 within has demonstrated associations with regulating the cell cycle, stress responses, and various intracellular states. Furthermore, Adh1 is extracellularly localized on the cell wall surface, where it plays roles in processes such as tissue invasion and host immune responses. Drawing from an analysis of gene structure, expression patterns, and fundamental functions, this review elucidates the intricate connections between Adh1 and various biological processes within , underscoring its potential implications for the prevention, diagnosis, and treatment of candidiasis.
PubMed: 38916139
DOI: 10.1080/1040841X.2024.2371510 -
The Journal of Chemical Physics Jun 2024We investigate roaming in the photodissociation of acetaldehyde (CH3CHO), providing insights into the contrasting roaming dynamics observed for this molecule compared to...
We investigate roaming in the photodissociation of acetaldehyde (CH3CHO), providing insights into the contrasting roaming dynamics observed for this molecule compared to formaldehyde. We carry out trajectory studies for full-dimensional acetaldehyde, supplemented with an analysis of a two-degree-of-freedom restricted model and obtain evidence for two distinct roaming pathways. Trajectories exhibit roaming at both shorter (9-11.5 au) and larger (14.5-22.9 au) maximum CH3-HCO separations, characterized by differing amounts of HCO rotation. No roaming trajectories were found in the intervening gap region. The roaming dynamics near 14.5-22.9 au are well-reproduced by the restricted model and involve passage through a centrifugal barrier, analogous to formaldehyde roaming. However, the shorter-range 9-11.5 au roaming appears unique to acetaldehyde and is likely facilitated by repulsive interactions absent in the simplified models. Phase space analysis reveals that this additional roaming pathway is inaccessible in the reduced dimensionality system. The findings suggest that acetaldehyde's increased propensity for roaming compared to formaldehyde may arise from the presence of multiple distinct roaming mechanisms rather than solely the higher roaming fragment mass.
PubMed: 38912673
DOI: 10.1063/5.0212443 -
Advances in Genetics 2024Modern humans evolved in Africa some 200,000 years ago, and since then, human populations have expanded and diversified to occupy a broad range of habitats and use... (Review)
Review
Modern humans evolved in Africa some 200,000 years ago, and since then, human populations have expanded and diversified to occupy a broad range of habitats and use different subsistence modes. This has resulted in different adaptations, such as differential responses to diseases and different abilities to digest or tolerate certain foods. The shift from a subsistence strategy based on hunting and gathering during the Palaeolithic to a lifestyle based on the consumption of domesticated animals and plants in the Neolithic can be considered one of the most important dietary transitions of Homo sapiens. In this text, we review four examples of gene-culture coevolution: (i) the persistence of the enzyme lactase after weaning, which allows the digestion of milk in adulthood, related to the emergence of dairy farming during the Neolithic; (ii) the population differences in alcohol susceptibility, in particular the ethanol intolerance of Asian populations due to the increased accumulation of the toxic acetaldehyde, related to the spread of rice domestication; (iii) the maintenance of gluten intolerance (celiac disease) with the subsequent reduced fitness of its sufferers, related to the emergence of agriculture and (iv) the considerable variation in the biosynthetic pathway of long-chain polyunsaturated fatty acids in native populations with extreme diets.
Topics: Humans; Diet; Biological Evolution; Animals; Cultural Evolution; Adaptation, Physiological; Lactase
PubMed: 38908898
DOI: 10.1016/bs.adgen.2024.01.004 -
Toxicon : Official Journal of the... Jun 2024Mushroom poisonings are common in the United States. Gyromitrin (acetaldehyde N-methyl-N-formylhydrazone) is a clinically significant mycotoxin primarily associated with...
Mushroom poisonings are common in the United States. Gyromitrin (acetaldehyde N-methyl-N-formylhydrazone) is a clinically significant mycotoxin primarily associated with the lorchel (i.e. the false morel) Gyromitra esculenta. Resemblance between 'true and false morels' has resulted in misidentification of Gyromitra spp. as edible and sought after Morchella spp., resulting in toxicity. Despite literature evidence outlining toxic sequalae, Gyromitra spp. mushrooms are commonly consumed and prepared for culinary purposes. Classic clinical teachings emphasize significant neurotoxicity, including seizures, associated with ingestion of gyromitrin-containing mushrooms, stemming from gyromitrin's terminal metabolite monomethylhydrazine. We performed a longitudinal descriptive review of the clinical toxicity associated with ingestion of mushroom species known or suspected to contain gyromitrin in cases reported to the Michigan Poison & Drug Information Center between January 1, 2002, to December 31, 2020. Our 19-year descriptive case series of gyromitrin-containing mushroom ingestions reported to our Center demonstrated a preponderance of gastrointestinal signs and symptoms, including hepatotoxicity. Of 118 identified cases, 108 (91.5%) of the reported ingestions involved Gyromitra esculenta. The most frequent clinical findings associated with symptomatic ingestions (n= 83) were the aforementioned gastrointestinal symptoms (n=62; 74.7%). Neurological symptoms were less frequent (n=22, 26.5%) while hepatotoxicity occurred in fewer patients (n=14; 16.9%). Of symptomatic patients, most were treated with symptomatic and supportive care (n=58; 70%). Pyridoxine was used in a total of seven patients (n=7; 8.4%) with either hepatotoxicity or neurotoxicity. Medical outcomes ranged from minor to major, with no reported deaths. Patient presentations (i.e. GI vs. neurotoxic symptoms) following ingestion of gyromitrin-containing mushrooms may be highly variable and multifactorial, owing to differences in dose ingested, geographical distribution, genetic variability of both patient and mushroom species, and species-specific differences in toxin composition. Future research warrants species-level identification of ingested gyromitrin-containing mushrooms and investigating the contribution of genetic polymorphisms to differences in clinical toxidromes.
PubMed: 38908526
DOI: 10.1016/j.toxicon.2024.107825 -
Nature Metabolism Jun 2024Alcohol use disorder (AUD) affects millions of people worldwide, causing extensive morbidity and mortality with limited pharmacological treatments. The liver is...
Alcohol use disorder (AUD) affects millions of people worldwide, causing extensive morbidity and mortality with limited pharmacological treatments. The liver is considered as the principal site for the detoxification of ethanol metabolite, acetaldehyde (AcH), by aldehyde dehydrogenase 2 (ALDH2) and as a target for AUD treatment, however, our recent data indicate that the liver only plays a partial role in clearing systemic AcH. Here we show that a liver-gut axis, rather than liver alone, synergistically drives systemic AcH clearance and voluntary alcohol drinking. Mechanistically, we find that after ethanol intake, a substantial proportion of AcH generated in the liver is excreted via the bile into the gastrointestinal tract where AcH is further metabolized by gut ALDH2. Modulating bile flow significantly affects serum AcH level and drinking behaviour. Thus, combined targeting of liver and gut ALDH2, and manipulation of bile flow and secretion are potential therapeutic strategies to treat AUD.
PubMed: 38902331
DOI: 10.1038/s42255-024-01063-2 -
Environmental Science & Technology Jun 2024Oxygenated volatile organic compounds (OVOCs), emitted in large quantities by the chemical industry, are a major contributor to the formation of ozone and subsequent...
Oxygenated volatile organic compounds (OVOCs), emitted in large quantities by the chemical industry, are a major contributor to the formation of ozone and subsequent particulate matter. For the efficient catalytic oxidation of OVOCs, the challenges of molecular activation and intermediate inhibition remain. The construction of bifunctional active sites with specific structures offers a promising way to overcome these problems. Here, the Pd@Layered-CoO/MFI bifunctional catalyst with core-shell active sites was rationally fabricated though a two-step ligand pyrolysis method, which exhibits a superb oxidation efficiency toward ethyl acetate (EA). Over this, 13.4% of EA (1000 ppm) can be oxidized at just 140 °C with a reaction rate of 13.85 mmol·g·s, around 176.7 times higher than that of the conventional Pd-CoO/MFI catalyst. The electronic coupling of the Pd-Co pair promotes the electron back-donation from Pd nanoparticles to the layered CoO shell and facilitates the formation of Pd species, which greatly enhances the adsorption and activation of the electron-rich C═O bond of the EA molecules. In addition, the synergy of these core-shell Pd@Layered-CoO sites accelerates the activation and transformation of *O species, which inhibit the formation of acetaldehyde and ethanol byproducts, ensuring the rapid total oxidation of EA molecules the Mars-van Krevelen mechanism. This work established a solid foundation for exploring robust bifunctional catalysts for deep OVOC purification.
PubMed: 38900969
DOI: 10.1021/acs.est.4c00632