Gene Encoding Alcohol Dehydrogenase Research Articles

The changes of chemical molecular components in soil organic matter are associated with fungus Mortierella capitata K.

Fungi play essential roles in the turnover of soil organic matter (SOM). However, it is unclear how fungi affect the chemical molecular composition of SOM. This study examined the effect of saprophytic soil fungus Mortierella capitata K on different soil carbon components and their molecular components. Genome sequencing revealed the ability of the strain to synthesize and degrade heterocycles, heteropolysaccharides, alkenes, terpenoids, steroids, amides, lipids, and amino acids. Subsequently, the turnover of SOM in M. capitata K inoculation with straw (KS) or without straw (K) addition was investigated via an aseptic microcosm experiment for 240 days. Pyrolysis gas chromatography-mass spectrometry analysis (Py-GCMS) showed that the molecular composition of SOM significantly changed with culture time in the two treatments. M. capitata K inoculation increased the relative abundance of tetradecanentitrile, dotriacontane, n-hexadecanoic acid, and n-dodecyl methacrylate in SOM during day 5–180. In contrast, the proportion of components in SOM (oxidizable by potassium permanganate) reduced after M. capitata K inoculation. Similarly, M. capitata K inoculation decreased the relative abundance of alkanes, alkenes, and alcohols in the original SOM on the 240th day. However, the above decline was effectively alleviated after straw addition. Straw addition significantly improved the abundance of n-hexadecanoic acid. RNA sequencing on the 30th day revealed the association between genes encoding alcohol dehydrogenase and SOM ester formation. Therefore, this study may provide insights into the complex feedback loops between microbial activities and molecular composition changes in SOM.

Network and meta-omics reveal the cooperation patterns and mechanisms in an efficient 1,4-dioxane-degrading microbial consortium

1,4-Dioxane is an emerging wastewater contaminant with probable human carcinogenicity. Our current understanding of microbial interactions during 1,4-dioxane biodegradation process in mixed cultures is limited. Here, we applied metagenomic, metatranscriptomic and co-occurrence network analyses to unraveling the microbial cooperation between degrader and non-degraders in an efficient 1,4-dioxane-degrading microbial consortium CH1. A 1,4-dioxane-degrading bacterium, Ancylobacter polymorphus ZM13, was isolated from CH1 and had a potential of being one of the important degraders due to its high relative abundance, highly expressed monooxygenase genes tmoABCDEF and high betweenness centrality of networks. The strain ZM13 cooperated obviously with 6 bacterial genera in the network, among which Xanthobacter and Mesorhizobium could be involved in the intermediates metabolism with responsible genes encoding alcohol dehydrogenase (adh), aldehyde dehydrogenase (aldh), glycolate oxidase (glcDEF), glyoxylate carboligase (gcl), malate synthase (glcB) and 2-isopropylmalate synthase (leuA) differentially high-expressed. Also, 1,4-dioxane facilitated the shift of biodiversity and function of CH1, and those cooperators cooperated with ZM13 in the way of providing amino acids or fatty acids, as well as relieving environmental stresses to promote biodegradation. These results provide new insights into our understandings of the microbial interactions during 1,4-dioxane degradation, and have important implications for predicting microbial cooperation and constructing efficient and stable synthetic 1,4-dioxane-degrading consortia for practical remediation.

Glycol/glycerol-fed electrically conductive aggregates suggest a mechanism of stimulating direct interspecies electron transfer in methanogenic digesters

The possibility of stimulating direct interspecies electron transfer (DIET) within aggregates of methanogenic digesters respectively with ethanol, glycol, and glycerol as a primary substrate was investigated to better understand the mechanisms of alcohol compounds stimulating DIET. Aggregates fed with ethanol, glycol, and glycerol were electrically conductive (10.4–19.4 uS/cm), with a temperature dependence of metallic-like conductivity. Close examination of transmission electron microscope images observed the potential interspecies connected networks assembled by filaments within these aggregates. Further investigations via metatranscriptomics found that, genes for electrically conductive pili (e-pili) (Log2FPKM, 9.39–10.96) and c-type cytochromes (8.90–9.64) were highly expressed within aggregates. Glycerol-fed aggregates exhibited the highest gene expression for e-pili, while glycol-fed aggregates exhibited the highest gene expression for c-type cytochromes. Methanothrix species were dominant and metabolically active within aggregates. Genes encoding the enzymes involved in carbon dioxide reduction were highly expressed in Methanothrix species, suggesting that they participated in DIET. In addition, transcript abundance of genes encoding alcohol dehydrogenase and NADH-quinone oxidoreductase in alcohol dehydrogenation closely associated with NADH/NAD+ transformation within glycol- and glycerol-fed aggregates was generally higher than that within ethanol-fed aggregates. These results, and the fact that NADH/NAD+ transformation was very linked to the ATP synthesis complex that further supported the formation of extracellular electrical connection components, e-pili and membrane-bound multi-heme c-type cytochromes (MHCs), provided a possibility that alcohol compounds comprised of hydroxy groups could stimulate DIET and more hydroxy groups comprised were better for this stimulation.

Comparative Genomic Analysis of Stenotrophomonas maltophilia Strain W18 Reveals Its Adaptative Genomic Features for Degrading Polycyclic Aromatic Hydrocarbons.

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants that are ubiquitous in the environment. Numerous bacteria have evolved to have degrading genes or pathways to degrade PAHs. Stenotrophomonas maltophilia strain W18 was found to be able to degrade PAHs. Including 43 other complete genome sequences of S. maltophilia strains, we performed a comparative genomic analysis of 44 S. maltophilia strains by running OrthoFinder. A KEGG pathway enrichment analysis of environmental and clinical isolates of S. maltophilia revealed that environmental isolates tended to enhance gene functions such as “energy metabolism,” “amino acid metabolism,” “xenobiotic biodegradation and metabolism,” and “folding, sorting, and degradation.” The pangenome of the 44 S. maltophilia strains was open, while the core genome was estimated to reach a steady plateau. Based on gene annotations, we inferred that most of the degradation potential came from the core genome of S. maltophilia, while character genes and accessory genes also contributed to the degradation ability of S. maltophilia W18. The genes expression level of core genes, character genes and accessory genes were proved by RT-qPCR experiment, and accessory genes encoding alcohol dehydrogenase were upregulated most compared with genes with similar functions. We performed a credible comparative genomic analysis of S. maltophilia strains. S. maltophilia W18 was set as a model PAH-degrading bacterium of this species in this study, which would provide guidance for understanding and predicting the degradation mechanisms of other PAH-degrading S. maltophilia strains lacking complete genome data or waiting to be determined.IMPORTANCE This study provided the latest comparative genomic analysis on Stenotrophomonas maltophilia strains and focused on analyzing their genomic features that allow them to adapt to natural environments. In this study, we set S. maltophilia W18 as a typical PAH-degrading strain of this species. By discussing the genomic adaptative features of degrading PAH, we can predict genomic adaptative features of other S. maltophilia PAH-degrading strains since the core function of this species is stable. The gene functions of how S. maltophilia environmental isolates are enhanced for adaptation to various natural environments compared with clinical isolates have been revealed. Combined with a pangenome analysis and RT-qPCR results, we have proved that core genes, character genes, and accessory genes are all involved in PAH degradation. Accessory genes encoding alcohol dehydrogenase were upregulated most compared with core and character genes with similar functions, which suggests that PAH metabolization potential might be enhanced by horizontal gene transfer.

Consolidated bioprocessing for bioethanol production by metabolically engineered Bacillus subtilis strains

Bioethanol produced by fermentative microorganisms is regarded as an alternative to fossil fuel. Bioethanol to be used as a viable energy source must be produced cost-effectively by removing expense-intensive steps such as the enzymatic hydrolysis of substrate. Consolidated bioprocessing (CBP) is believed to be a practical solution combining saccharification and fermentation in a single step catalyzed by a microorganism. Bacillus subtills with innate ability to grow on a diversity of carbohydrates seems promising for affordable CBP bioethanol production using renewable plant biomass and wastes. In this study, the genes encoding alcohol dehydrogenase from Z. mobilis (adhZ) and S. cerevisiae (adhS) were each used with Z. mobilis pyruvate decarboxylase gene (pdcZ) to create ethanologenic operons in a lactate-deficient (Δldh) B. subtilis resulting in NZ and NZS strains, respectively. The S. cerevisiae adhS caused significantly more ethanol production by NZS and therefore was used to make two other operons including one with double copies of both pdcZ and adhS and the other with a single pdcZ but double adhS genes expressed in N(ZS)2 and NZS2 strains, respectively. In addition, two fusion genes were constructed with pdcZ and adhS in alternate orientations and used for ethanol production by the harboring strains namely NZ:S and NS:Z, respectively. While the increase of gene dosage was not associated with elevated carbon flow for ethanol production, the fusion gene adhS:pdcZ resulted in a more than two times increase of productivity by strain NS:Z as compared with NZS during 48 h fermentation. The CBP ethanol production by NZS and NS:Z using potatoes resulted in 16.3 g/L and 21.5 g/L ethanol during 96 h fermentation, respectively. For the first time in this study, B. subtilis was successfully used for CBP ethanol production with S. cerevisiae alcohol dehydrogenase. The results of the study provide insights on the potentials of B. subtilis for affordable bioethanol production from inexpensive plant biomass and wastes. However, the potentials need to be improved by metabolic and process engineering for higher yields of ethanol production and plant biomass utilization.

Biosyntheses of geranic acid and citronellic acid from monoterpene alcohols by Saccharomyces cerevisiae.

Geraniol is one of the important aromatic ingredients in alcoholic beverages. Bioconversions of geraniol to other terpenoids and genes involved in the oxidation of geraniol were investigated. Geranic acid and citronellic acid were detected in yeast culture, where geraniol or nerol was added. Addition of citral, a mixture of geranial and neral, resulted in the production of geranic acid and citronellic acid, whereas the addition of citral or citronellal resulted in the production of citronellic acid, suggesting that citronellic acid might be produced through the conversion of citral to citronellal followed by the oxidation of citronellal. Consumption of geraniol and production of geranic acid, citronellic acid, and citronellol were affected in adh1Δ, adh3Δ, adh4Δ, and sfa1Δ yeast strains, which possess single deletion of a gene encoding alcohol dehydrogenase. This is the first report of the bioconversion of monoterpene alcohols, geraniol and nerol, to geranic acid and citronellic acid in yeast culture.

High alcohol-producing Klebsiella pneumoniae causes fatty liver disease through 2,3-butanediol fermentation pathway in vivo

ABSTRACT High alcohol-producing Klebsiella pneumoniae (HiAlc Kpn) in the gut microbiota had been demonstrated to be the causative agent of fatty liver disease (FLD). However, the catabolic pathways for alcohol production in vivo remain unclear. Here, we characterized the genome of HiAlc and medium alcohol-producing (MedAlc) Kpn and constructed an adh (an essential gene encoding alcohol dehydrogenase) knock-out HiAlc Kpn W14 strain (W14Δadh) using CRISPR-Cas9 system. Subsequently, we established the mouse model via gavage administration of HiAlc Kpn W14 and W14 Δadh strains, respectively. Proteome and metabolome analysis showed that 10 proteins and six major metabolites involved in the 2,3-butanediol fermentation pathway exhibited at least a three-fold change or greater during intestinal growth. Compared with HiAlc Kpn W14-fed mice, W14Δadh-fed mice with weak alcohol-producing ability did not show apparent pathological changes at 4 weeks, although some steatotic hepatocytes were observed at 12 weeks. Our data demonstrated that carbohydrate substances are catabolized to produce alcohol and 2,3-butanediol via the 2,3-butanediol fermentation pathway in HiAlc Kpn, which could be a promising clinical diagnostic marker. The production of high amounts of endogenous alcohol is responsible for the observed steatosis effects in hepatocytes in vivo.

Alcohol dehydrogenase modulates quorum sensing in biofilm formations of Acinetobacter baumannii

Acinetobacter baumannii (A. baumannii) is a common opportunistic nosocomial pathogen, which is able to produce biofilms on the surface of indwelling medical devices, and consequentially causes severe infections in clinical settings. In order to identify genes that involved in the biofilm formation of A. baumannii, the differential expression of genes between biofilms and planktonic cells was analyzed by RNAseq assay and validated in clinical isolates. The RNAseq data showed that 264 genes were up-regulated, while 240 genes were down-regulated in the biofilms of A. baumannii. Among them, the gene encoding alcohol dehydrogenase (ADH), a known molecule of bacterial quorum sensing (QS) system that plays a key role in biofilm formation bacteria, was one of the most up-regulated gene in both reference strains and clinical isolates. Functional studies using ADH inhibitor disulfiram and activator taurine further demonstrated that the presence of disulfiram significantly inhibit the cell growth, motility and biofilm formation, paralleled by a decreased expression of QS-related genes, including AbaI, A1S_0109, and A1S_0112, in a dose-dependent manner; vice versa, the addition of ADH activator taurine, and QS molecule C12- homoserine lactone synthase (HSL) led a dose-dependent increase of bacterial growth, motility and biofilm production, along with an increased expression of QS-related genes in both reference strains and clinical isolates of A. baumannii. These results suggested that the ADH was a key molecule able to modulate the QS system and promote the biofilm formation, growth and motility in A. baumannii.

Genetic variants associated with alcohol dependence co-ordinate regulation of ADH genes in gastrointestinal and adipose tissues

GWAS studies have identified genetic variants associated with Alcohol Dependence (AD), but how they link to genes, their regulation and disease traits, remains largely unexplored. Here we integrated information on the 3D genome organization with expression quantitative loci (eQTLs) analysis, using CoDeS3D, to identify the functional impacts of single nucleotide polymorphisms associated with AD (p < 1 × 10−6). We report that 42% of the 285 significant tissue-specific regulatory interactions we identify were associated with four genes encoding Alcohol Dehydrogenase - ADH1A, ADH1B, ADH1C and ADH4. Identified eQTLs produced a co-ordinated regulatory action between ADH genes, especially between ADH1A and ADH1C within the subcutaneous adipose and gastrointestinal tissues. Five eQTLs were associated with regulatory motif alterations and tissue-specific histone marks consistent with these variants falling in enhancer and promoter regions. By contrast, few regulatory connections were identified in the stomach and liver. This suggests that changes in gene regulation associated with AD are linked to changes in tissues other than the primary sites of alcohol absorption and metabolism. Future work to functionally characterise the putative regulatory regions we have identified and their links to metabolic and regulatory changes in genes will improve our mechanistic understanding of AD disease development and progression.

Transcriptome analysis of the palmarosa Cymbopogon martinii inflorescence with emphasis on genes involved in essential oil biosynthesis

Cymbopogon martinii belongs to the family Poaceae and provides an aromatic essential oil of large applications in fragrance, perfumery, cosmetics and pharmaceuticals. The essential oil from this genus has two dominating monoterpenes, geranyl acetate and geraniol. Owing to the tremendous applications of the essential oil from this genus, knowledge of the biochemical and molecular regulatory processes and expressions of genes involved in terpenoid biosynthesis pathway, is highly desirable to improve the quality and yield of essential oil. We performed high-throughput transcriptome sequencing of C. martinii for identification of the genes related to terpenoids biosynthesis using Illumina HiSeq-2000 platform. In the present study, approximately 286,309,78 reads of high quality were generated. De novo assembly yielded 96,470 unigenes (≥200 bp) and 84,168 (≥500 bp). Functional annotation of total 96,470 (56%) unigenes was done. More than 4500 enriched unigenes were assigned to 367 KEGG pathways among various categories, i.e. protein processing, cellular processes, metabolism, steroid biosynthesis, and others. 913 unigenes in the metabolism category were assigned to 287 metabolic pathways linked with secondary metabolism. To explore the putative functions of six genes encoding alcohol dehydrogenase, geranyldiphosphate synthase, fernasyldiphosphate synthase, aldehyde dehydrogenase, aldo-keto reductase and alcohol acyltransferase expression patterns were studies using qRT-PCR. We have also identified 60 transcription factors in C. martini transcriptome using Plant Transcription factor database. To the best of our knowledge, this is the first-ever report on the C. martinii inflorescence transcriptome which will facilitate the understanding of the molecular mechanisms of essential oil biosynthesis in the genus Cymbopogon and related plant families.

Genetic variants of alcohol-metabolizing enzymes in Brugada syndrome: Insights into syncope after drinking alcohol.

BackgroundPatients with Brugada syndrome (BrS) are known to have arrhythmic events after alcohol drinking and are recommended to avoid its excessive intake. Mechanisms underlying the alcohol‐induced cardiac events are however unknown. This study aimed to test the hypothesis whether activity of alcohol‐metabolizing enzymes determines fatal arrhythmic events after drinking alcohol.MethodsA total of 198 Japanese patients with BrS were enrolled in this study. These patients were classified into symptomatic (n = 90) and asymptomatic (n = 108) groups. The former was divided into an alcohol‐related group (syncope after alcohol drinking, n = 16) and an alcohol‐unrelated group (n = 74). Polymerase chain reaction was performed to determine genetic variants of genes encoding alcohol dehydrogenase 1B (ADH1B) and aldehyde dehydrogenase 2 (ALDH2).ResultsThe genotype distribution for ALDH2 was not significantly different between symptomatic and asymptomatic groups and between alcohol‐related and alcohol‐unrelated groups. The genotype distribution for ADH1B was not significantly different between symptomatic and asymptomatic groups, but the genotype ADH1B His/His was significantly more prevalent in the alcohol‐related group than in the alcohol‐unrelated group (81.3% vs 50%, P = .023). In multivariate logistic regression analysis, the genotype of ADH1B His/His was independently associated with syncope after alcohol drinking (odds ratio, 5.746; 95% confidence interval, 1.580‐28.421; P = .007).ConclusionsArrhythmic events after alcohol drinking was associated with enhanced activity of alcohol‐metabolizing enzyme ADH1B in our cohort of BrS. Therefore, the lifestyle change to avoid the excessive alcohol intake deserves attention.

Transcriptome profiling of Gossypium arboreum during fiber initiation and the genome-wide identification of trihelix transcription factors

Cotton fiber initiation is the first step in fiber development, and it determines the yield. Here, genome-wide transcriptome profiling of Gossypium arboreum was performed to determine the molecular basis of cotton fiber initiation. A comparison of the transcriptomes of fiber-bearing ovules at −0.5, 0, 0.5, 1, 1.5, 2, 2.5 and 3 d post-anthesis detected 12,049 differentially expressed genes that mainly participated in ribosome, carbon metabolism and amino acid biosynthesis pathways. Genes encoding alcohol dehydrogenase 1 and hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase, involving in fatty acid degradation and flavonoid biosynthesis, were enriched. Furthermore, 1049 differentially expressed transcription factors were identified. Among these, 17 were trihelix family transcription factors, which play important roles in plant development and responses to biotic and abiotic stresses. In total, 52 full-length trihelix genes, named as GaGTs, were identified in G. arboreum and located in 12 of the 13 cotton chromosomes. Transcriptomic data and a quantitative real-time PCR analysis indicated that several GaGTs were significantly induced during fiber initiation in G. arboreum. Thus, the genome-wide comprehensive analysis of gene expression in G. arboreum fiber initiation will serve as a useful resource for unraveling the functions of specific genes. The phylogenetic relationships and expression analyses of the G. arboreum trihelix genes established a solid foundation for future comprehensive functional analyses of the GaGTs.

Genomewide Association Study of Alcohol Dependence and Related Traits in a Thai Population.

Alcohol use (both quantity and dependence) is moderately heritable, and genomewide association studies (GWAS) have identified risk genes in European, African, and Asian populations. The most reproducibly identified risk genes affect alcohol metabolism. Well-known functional variants at the gene encoding alcohol dehydrogenase B and other alcohol dehydrogenases affect risk in European and African ancestry populations. Similarly, variants mapped to these same genes and a well-known null variant that maps to the gene that encodes aldehyde dehydrogenase 2 (ALDH2) also affect risk in various Asian populations. In this study, we completed the first GWAS for 3 traits related to alcohol use in a Thai population recruited initially for studies of methamphetamine dependence. All subjects were evaluated with the Thai version of the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). A total of 1,045 subjects were available for analysis. Three traits were analyzed: flushing, maximum number of alcoholic beverages consumed in any lifetime 24-hour period ("MAXDRINKS"), and DSM-IV alcohol dependence criterion count. We also conducted a pleiotropy analysis with major depression, the only other psychiatric trait where summary statistics from a large-scale Asian-population GWAS are available. All 3 traits showed genomewide significant association with variants near ALDH2, with significance ranging from 2.01×10-14 (for flushing; lead single nucleotide polymorphism (SNP) PTPN11* rs143894582) to pmeta =5.80×10-10 (for alcohol dependence criterion count; lead SNP rs149212747). These lead SNPs flank rs671 and span a region of over a megabase, illustrating the need for prior biological information in identifying the actual effect SNP, rs671. We also identified significant pleiotropy between major depression and flushing. These results are consistent with prior findings in Asian populations and add new information regarding alcohol use-depression pleiotropy.

Genetic Engineering of an Unconventional Yeast for Renewable Biofuel and Biochemical Production.

Yarrowia lipolytica is a non-pathogenic, dimorphic and strictly aerobic yeast species. Owing to its distinctive physiological features and metabolic characteristics, this unconventional yeast is not only a good model for the study of the fundamental nature of fungal differentiation but is also a promising microbial platform for biochemical production and various biotechnological applications, which require extensive genetic manipulations. However, genetic manipulations of Y. lipolytica have been limited due to the lack of an efficient and stable genetic transformation system as well as very high rates of non-homologous recombination that can be mainly attributed to the KU70 gene. Here, we report an easy and rapid protocol for the efficient genetic transformation and for gene deletion in Y. lipolytica Po1g. First, a protocol for the efficient transformation of exogenous DNA into Y. lipolytica Po1g was established. Second, to achieve the enhanced double-crossover homologous recombination rate for further deletion of target genes, the KU70 gene was deleted by transforming a disruption cassette carrying 1 kb homology arms. Third, to demonstrate the enhanced gene deletion efficiency after deletion of the KU70 gene, we individually deleted 11 target genes encoding alcohol dehydrogenase and alcohol oxidase using the same procedures on the KU70 knockout platform strain. It was observed that the rate of precise homologous recombination increased substantially from less than 0.5% for deletion of the KU70 gene in Po1g to 33%-71% for the single gene deletion of the 11 target genes in Po1g KU70Δ. A replicative plasmid carrying the hygromycin B resistance marker and the Cre/LoxP system was constructed, and the selection marker gene in the yeast knockout strains was eventually removed by expression of Cre recombinase to facilitate multiple rounds of targeted genetic manipulations. The resulting single-gene deletion mutants have potential applications in biofuel and biochemical production.

Genetic Engineering of an Unconventional Yeast for Renewable Biofuel and Biochemical Production

Yarrowia lipolytica is a non-pathogenic, dimorphic and strictly aerobic yeast species. Owing to its distinctive physiological features and metabolic characteristics, this unconventional yeast is not only a good model for the study of the fundamental nature of fungal differentiation but is also a promising microbial platform for biochemical production and various biotechnological applications, which require extensive genetic manipulations. However, genetic manipulations of Y. lipolytica have been limited due to the lack of an efficient and stable genetic transformation system as well as very high rates of non-homologous recombination that can be mainly attributed to the KU70 gene. Here, we report an easy and rapid protocol for the efficient genetic transformation and for gene deletion in Y. lipolytica Po1g. First, a protocol for the efficient transformation of exogenous DNA into Y. lipolytica Po1g was established. Second, to achieve the enhanced double-crossover homologous recombination rate for further deletion of target genes, the KU70 gene was deleted by transforming a disruption cassette carrying 1 kb homology arms. Third, to demonstrate the enhanced gene deletion efficiency after deletion of the KU70 gene, we individually deleted 11 target genes encoding alcohol dehydrogenase and alcohol oxidase using the same procedures on the KU70 knockout platform strain. It was observed that the rate of precise homologous recombination increased substantially from less than 0.5% for deletion of the KU70 gene in Po1g to 33%-71% for the single gene deletion of the 11 target genes in Po1g KU70Δ. A replicative plasmid carrying the hygromycin B resistance marker and the Cre/LoxP system was constructed, and the selection marker gene in the yeast knockout strains was eventually removed by expression of Cre recombinase to facilitate multiple rounds of targeted genetic manipulations. The resulting single-gene deletion mutants have potential applications in biofuel and biochemical production.

Interactions Between Alcohol Metabolism Genes and Religious Involvement in Association With Maximum Drinks and Alcohol Dependence Symptoms.

Variations in the genes encoding alcohol dehydrogenase (ADH) enzymes are associated with both alcohol consumption and dependence in multiple populations. Additionally, some environmental factors have been recognized as modifiers of these relationships. This study examined the modifying effect of religious involvement on relationships between ADH gene variants and alcohol consumption-related phenotypes. Subjects were African American, European American, and Hispanic American adults with lifetime exposure to alcohol (N = 7,716; 53% female) from the Collaborative Study on the Genetics of Alcoholism. Genetic markers included ADH1Brs1229984, ADH1B-rs2066702, ADH1C-rs698, ADH4-rs1042364, and ADH4-rs1800759. Phenotypes were maximum drinks consumed in a 24-hour period and total number of alcohol dependence symptoms according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Religious involvement was defined by self-reported religious services attendance. Both religious involvement and ADH1B-rs1229984 were negatively associated with the number of maximum drinks consumed and the number of lifetime alcohol dependence symptoms endorsed. The interactions of religious involvement with ADH1B-rs2066702, ADH1C-rs698, and ADH4-rs1042364 were significantly associated with maximum drinks and alcohol dependence symptoms. Risk variants had weaker associations with maximum drinks and alcohol dependence symptoms as a function of increasing religious involvement. This study provided initial evidence of a modifying effect for religious involvement on relationships between ADH variants and maximum drinks and alcohol dependence symptoms.

Chilling- and Freezing-Induced Alterations in Cytosine Methylation and Its Association with the Cold Tolerance of an Alpine Subnival Plant, Chorispora bungeana.

Chilling (0–18°C) and freezing (<0°C) are two distinct types of cold stresses. Epigenetic regulation can play an important role in plant adaptation to abiotic stresses. However, it is not yet clear whether and how epigenetic modification (i.e., DNA methylation) mediates the adaptation to cold stresses in nature (e.g., in alpine regions). Especially, whether the adaptation to chilling and freezing is involved in differential epigenetic regulations in plants is largely unknown. Chorispora bungeana is an alpine subnival plant that is distributed in the freeze-thaw tundra in Asia, where chilling and freezing frequently fluctuate daily (24 h). To disentangle how C. bungeana copes with these intricate cold stresses through epigenetic modifications, plants of C. bungeana were treated at 4°C (chilling) and -4°C (freezing) over five periods of time (0–24 h). Methylation-sensitive amplified fragment-length polymorphism markers were used to investigate the variation in DNA methylation of C. bungeana in response to chilling and freezing. It was found that the alterations in DNA methylation of C. bungeana largely occurred over the period of chilling and freezing. Moreover, chilling and freezing appeared to gradually induce distinct DNA methylation variations, as the treatment went on (e.g., after 12 h). Forty-three cold-induced polymorphic fragments were randomly selected and further analyzed, and three of the cloned fragments were homologous to genes encoding alcohol dehydrogenase, UDP-glucosyltransferase and polygalacturonase-inhibiting protein. These candidate genes verified the existence of different expressive patterns between chilling and freezing. Our results showed that C. bungeana responded to cold stresses rapidly through the alterations of DNA methylation, and that chilling and freezing induced different DNA methylation changes. Therefore, we conclude that epigenetic modifications can potentially serve as a rapid and flexible mechanism for C. bungeana to adapt to the intricate cold stresses in the alpine areas.

Is nonalcoholic fatty liver disease an endogenous alcoholic fatty liver disease? – A mechanistic hypothesis

Nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) are so similar that only a detailed history of alcohol intake can distinguish one from the other. Because subjects with NAFLD produce significantly more endogenous ethanol (EE) than controls, some researchers suspected that these similarities are not merely coincidental. For this reason, it was attempted to show that NAFLD is actually an endogenous alcoholic fatty liver disease (EAFLD). However, negligible blood-alcohol concentration (BAC) and the inability of gut microbiota to produce hepatotoxic concentrations of EE rejected this hypothesis. To clarify these conflicting results, we provide a mechanistic framework explaining how NAFLD may be an EAFLD. First of all, the key finding is that ethanol is a prodrug, enabling the idea that AFLD may develop with negligible/absent BAC. Second, extrahepatic acetaldehyde (ACD) alone recapitulates AFLD and is about 330-fold more hepatotoxic than that generated inside the liver. Third, gut microbiota can even produce much larger amounts of EE than those currently considered cirrhotogenic for man. Fourth, an extensive gut-liver axis first-pass metabolism of ethanol prevents the development of significant BAC in NAFLD. Fifth, all genes involved in EE metabolism are upregulated in the livers of patients with nonalcoholic steatohepatitis (NASH). Last, overexpression of the gene encoding alcohol dehydrogenase (ADH) 4 implicates liver exposure to high concentrations of EE. In conclusion, this work provides mechanistic explanation supporting the assumption that NAFLD may indeed be an EAFLD. If validated by further testing, the hypothesis may help develop novel therapeutic and preventive strategies against this ubiquitous condition.

Genetic variants in or near ADH1B and ADH1C affect susceptibility to alcohol dependence in a British and Irish population.

Certain single nucleotide polymorphisms (SNPs) in genes encoding alcohol dehydrogenase (ADH) enzymes confer a significant protective effect against alcohol dependence syndrome (ADS) in East Asian populations. Recently, attention has focused on the role of these SNPs in determining ADS risk in European populations. To further elucidate these associations, SNPs of interest in ADH1B, ADH1C and the ADH1B/1C intergenic region were genotyped in a British and Irish population (ADS cases n = 1076: controls n = 1027) to assess their relative contribution to ADS risk. A highly significant, protective association was observed between the minor allele of rs1229984 in ADH1B and ADS risk [allelic P = 8.4 × 10(-6) , odds ratio (OR) = 0.26, 95 percent confidence interval, 0.14, 0.49]. Significant associations were also observed between ADS risk and the ADH1B/1C intergenic variant, rs1789891 [allelic P = 7.2 × 10(-5) , OR = 1.4 (1.2, 1.6)] and three non-synonymous SNPs rs698, rs1693482 and rs283413 in ADH1C. However, these associations were not completely independent; thus, while the ADH1B rs1229984 minor allele association was independent of those of the intergenic variant rs1789891 and the three ADH1C variants, the three ADH1C variants were not individually independent. In conclusion, the rare ADH1B rs1229984 mutation provides significant protection against ADS in this British and Irish population; other variants in the ADH gene cluster also alter ADS risk, although the strong linkage disequilibrium between SNPs at this location precluded clear identification of the variant(s) driving the associations.

Isolation of an alcohol dehydrogenase cDNA from and characterization of its expression in chrysanthemum under waterlogging

A PCR strategy was used to isolate a full-length CgADH (alcohol dehydrogenase) cDNA from chrysanthemum. The gene putatively encodes a 378 residue polypeptides, which shares 95% homology with tomato alcohol dehydrogenase class III. Endogenous ethylene generated in waterlogged Chrysanthemum zawadskii was enhanced by exogenous ethylene but decreased by 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action. In waterlogged roots, the transcription of the gene encoding alcohol dehydrogenase (ADH, EC 1.1.1.1) increased rapidly but transiently, peaking at 7.5 fold the non-waterlogged level after 2h of stress. Waterlogging elevated ADH activity after a prolonged episode of stress. The exogenous supply of 40μLL−1 ethylene suppressed the production of ethanol, while that of 4μLL−1 1-MCP enhanced it. Ethylene appeared to suppress an acceleration of both CgADH expression and fermentation, and alleviates ethanolic fermentation probably through by as a signal to acceleration of waterlogging-induced aerenchyma formation. This supports the previously observed phenomenon that the expression level of ADH gene is regulated by the local level of physiologically active ethylene. The relevance of the CgADH gene in relation to chrysanthemum waterlogging was discussed as well.