Alcohol Dehydrogenase Enzyme Research Articles

Electrostatic ethanol fermentation: Experimental study and kinetic-based metabolic modeling

Due to the electrical nature of the cell, it is possible to modulate its behavior through the application of non-lethal external electric fields to improve fermentation processes. In this work, a microbial cell system with a chamber and two electrodes inside and connected to a voltage source was used. One of the electrodes was kept isolated to create an electric field without the flow of current. Cultures with two ethanol-producing microbial strains (Saccharomyces cerevisiae and Zymomonas mobilis) were conducted in this device. The application of voltages between 0 and 18 V was evaluated to determine the impact of the generated electric field on ethanol production. To analyze the possible effect of the field on the central carbon metabolism in each strain, biochemical-based kinetic models were formulated to describe the experimental fermentation kinetics obtained.It was found that low applied voltages did not have significant effects on growth rate in either strain, but all voltages evaluated increased substrate consumption and ethanol production rate in Z. mobilis, while only 18 V affected these rates in S. cerevisiae, indicating that Z. mobilis was the most sensitive to the electric field. At the end of the fermentation, significant increases in ethanol yields of 10.7% and 19.5% were detected for S. cerevisiae and Z. mobilis, respectively. The proposed mathematical models showed that substrate transport through the membrane catalyzed by the phosphotransferase system (PTS) for Z. mobilis and hexose transport proteins mechanism and hexokinase (HK) activity for S. cerevisiae and the transformation of pyruvate to ethanol, catalyzed by the decarboxylase (PDC) and alcohol dehydrogenase (ADH) enzymes, were the reactions most affected by the application of the external field.

Structure-driven development of a biomimetic rare earth artificial metalloprotein

The 2011 discovery of the first rare earth-dependent enzyme in methylotrophic Methylobacterium extorquens AM1 prompted intensive research toward understanding the unique chemistry at play in these systems. This enzyme, an alcohol dehydrogenase (ADH), features a La3+ ion closely associated with redox-active coenzyme pyrroloquinoline quinone (PQQ) and is structurally homologous to the Ca2+-dependent ADH from the same organism. AM1 also produces a periplasmic PQQ-binding protein, PqqT, which we have now structurally characterized to 1.46-Å resolution by X-ray diffraction. This crystal structure reveals a Lys residue hydrogen-bonded to PQQ at the site analogously occupied by a Lewis acidic cation in ADH. Accordingly, we prepared K142A- and K142D-PqqT variants to assess the relevance of this site toward metal binding. Isothermal titration calorimetry experiments and titrations monitored by UV-Vis absorption and emission spectroscopies support that K142D-PqqT binds tightly (Kd = 0.6 ± 0.2 μM) to La3+ in the presence of bound PQQ and produces spectral signatures consistent with those of ADH enzymes. These spectral signatures are not observed for WT- or K142A-variants or upon addition of Ca2+ to PQQ ⸦ K142D-PqqT. Addition of benzyl alcohol to La3+-bound PQQ ⸦ K142D-PqqT (but not Ca2+-bound PQQ ⸦ K142D-PqqT, or La3+-bound PQQ ⸦ WT-PqqT) produces spectroscopic changes associated with PQQ reduction, and chemical trapping experiments reveal the production of benzaldehyde, supporting ADH activity. By creating a metal binding site that mimics native ADH enzymes, we present a rare earth-dependent artificial metalloenzyme primed for future mechanistic, biocatalytic, and biosensing applications.

Formate‐Mediated Electroenzymatic Synthesis via Biological Cofactor NADH

Synthetic biohybrid systems by coupling artificial system with nature’s machinery may offer a disruptive solution to address the global energy crisis. We developed a versatile electroenzymatic pathway for the continuous synthesis of valuable chemicals, facilitated by formate‐driven NADH regeneration. Utilising a bismuth electrocatalyst, we achieved stable CO2 reduction to formate with approximately 90% Faraday efficiency at a current density of 150 mA cm−2. The generated formate acts as a mediator to regenerate NADH, which is then coupled with immobilised redox enzymes—alcohol dehydrogenase (ADH), L‐lactate dehydrogenase (LDH), and L‐glutamate dehydrogenase (GDH)—to produce targeted chemicals at significant rates and exceptionally high turnover numbers (1.8×106 to 3.1×106). These achievements not only underscore the efficiency of the system but also its practical applicability in industrial settings. By leveraging in situ generated formate, this innovative approach demonstrates the potential of integrating electrocatalysis with enzymatic reactions for sustainable and efficient chemical production on a practical scale.

Host Plants and Fertilization Mediated Life History of American Serpentine Leaf Miner, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae).

Herbivorous insects depend on the host plant to optimize their overall reproductive success, and balanced fertilization may alter the plant's quality against herbivory. Life history traits of the Liriomyza trifolii (Burgess) were determined under laboratory conditions using either unfertilized and fertilized plants of bean [Phaseolus vulgaris L. (Fabaceae)], chrysanthemum [Chrysanthemum × morifolium (Asteraceae)], potato [Solanum tuberosum (Solanaceae)], bell pepper [Capsicum annuum (Solanaceae)], and tomato [Solanum lycopersicum (Solanaceae)]. Results indicated that L. trifolii completed development on all studied unfertilized and fertilized plants. Nevertheless, a higher performance of the leaf miner was observed on bean and bell pepper plants compared to the other plants. Furthermore, there was an interaction of the host plant and fertilization with Calcium Aria or Sitam negatively affecting the fitness-related traits of the leaf miner. Application of these fertilizers resulted in delayed immature development of L. trifolii, decreased survival rate, and reduced adult longevity and fecundity. The activity of cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) enzymes, as well as phenolic, flavonoid, and lignin content were higher in Calcium Aria + Sitam fertilized plants, intermediate in Calcium Aria and Sitam treated plants, and the lower in unfertilized plants. The development and survival of L. trifolii on different host plants, considering fertilization options, become important for deploying cultural control practices against this important pest species.

Enhanced co-production of hydrogen and ethanol from brown algae fermentation by supplementing nano zero-valent iron (nZVI)

Nano zero-valent iron (nZVI) has been shown to facilitate biofuel production, notably in hydrogen generation. However, its effect on bioethanol production is rarely studied, and even less so on its impact on hydrogen and ethanol co-production. This study therefore conducted ethanol-type hydrogen-producing fermentation with brown algae to explore the effect of nZVI. With the supplementation of nZVI, fermentation was accelerated and the production of hydrogen and ethanol were both significantly enhanced. At the optimal nZVI concentration of 100 mg/L, the production of hydrogen and ethanol increased by 71.44% and 65.11%, respectively. A high hydrogen yield of 2.32 mol/mol-mannitol was achieved. The ethanol yield (1.86 mol/mol-mannitol) reached 93% of the theoretical maximal yield with a high selectivity of 91.09%. Electron distribution analysis showed that nZVI increased the total electron amounts of fermentation, and directed more electrons to ethanol than hydrogen. The reduced redox potential (ORP) and increased NADH level further confirmed the role of nZVI. Moreover, nZVI fostered Fe2+ availability to hydrogen-producing bacteria, enhancing the enzymes hydrogenase and alcohol dehydrogenase, as well as cell biomass. The bioenergy conversion efficiency (BioECE) improved from 19.08% to 31.74% with 100 mg/L nZVI treatment. This study provided a first demonstration regarding the role of nZVI in hydrogen and ethanol co-production, highlighting the great potential of multiple bioenergy recovery from marine biomass.

Expression and characterization of monofunctional alcohol dehydrogenase enzymes in Clostridium thermocellum

Clostridium thermocellum is a thermophilic anaerobic bacterium that could be used for cellulosic biofuel production due to its strong native ability to consume cellulose, however its ethanol production ability needs to be improved to enable commercial application. In our previous strain engineering work, we observed a spontaneous mutation in the native adhE gene that reduced ethanol production. Here we attempted to complement this mutation by heterologous expression of 18 different alcohol dehydrogenase (adh) genes. We were able to express all of them successfully in C. thermocellum. Surprisingly, however, none of them increased ethanol production, and several actually decreased it. Our findings contribute to understanding the correlation between C. thermocellum ethanol production and Adh enzyme cofactor preferences. The identification of a set of adh genes that can be successfully expressed in this organism provides a foundation for future investigations into how the properties of Adh enzymes affect ethanol production.

Exogenous application of melatonin attenuates waterlogging stress through adopting quiescence adaptation technique in tomato seedlings

Waterlogging (WL) is a major limiting factor in global crop production and seriously limits growth and yield improvement in low-lying rainfed regions. Melatonin (MT) is a vital phytohormone that functions as a "master regulator" in multiple facets related to plant growth and development, in addition to maintaining a potential role in response to stresses. However, the pharmacological role of MT in attenuating waterlogging stress in tomato largely remains elucidated. The objective of the current investigation is to justify the physiological regulatory mechanism of tomato seedlings exposed to WL and the putative functions of MT to mitigate the adverse effects of WL. Tomato seedlings were grown on substrate (peat: vermiculite, 2:1, v/v) and at the 4th leaf stage subjected to waterlogging stress for 10 days and seedlings were foliar sprayed with melatonin during waterlogging stress. The results revealed that WL significantly arrested tomato seedlings growth, and reduced pigment content coincided with enhanced leaf senescence. MT supplementation attenuated WL-induced oxidative damage through increasing osmoprotectants activity, elevating antioxidant enzyme functioning synchronized with inhibiting excess reactive oxygen species (ROS) production. The concentrations of MT (28 %), abscisic acid (ABA, 170 %), and 1-aminocyclopropane-1-carboxylic acid (ACC, 129 %) were increased, while indole acetic acid (IAA, 15 %), jasmonic acid (JA, 55 %) and gibberellic acid (GA3, 26 %) content were decreased in only WL seedlings roots relative to control seedlings. The core anaerobic respiration enzyme alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) activity were elevated by 127 % and 163 %, respectively at day 10 in WL+MT received seedlings than control. WL treatment varyingly contributed on nutrient content, as evidenced that N+, K+, and Ca2+ content decreased, whereas Mn2+, Fe2+, and Mg2+ content increased and MT addition reversed their concentrations under similar stress conditions. Exogenous MT promoted WL-tolerance of tomato by positively suppressing respiratory burst oxidase homologs (RBOH)-regulating gene expression while up-regulating ethylene biosynthesis gene transcription. Most importantly, programmed cell death (PCD) regulated enzyme caspase-3 activity concurred with PCD-induced gene (caspase-3, pirin, TBN1) expression significantly inhibited by MT application. In general, these findings reveal that external supplementation with MT can improve plant tolerance to WL through complex processes and multifaceted mechanisms.

Ion-combination specific effects driving the enzymatic activity of halophilic alcohol dehydrogenase 2 from Haloferax volcanii in aqueous ionic liquid solvent mixtures.

Biocatalysis in ionic liquids enables novel routes for bioprocessing. Enzymes derived from extremophiles promise greater stability and activity under ionic liquid (IL) influence. Here, we probe the enzyme alcohol dehydrogenase 2 from the halophilic archaeon Haloferax volcanii in thirteen different ion combinations for relative activity and analyse the results against molecular dynamics (MD) simulations of the same IL systems. We probe the ionic liquid property space based on ion polarizability and molecular electrostatic potential. Using the radial distribution functions, survival probabilities and spatial distribution functions of ions, we show that cooperative ion-ion interactions determine ion-protein interactions, and specifically, strong ion-ion interactions equate to higher enzymatic activity if neither of the ions interact strongly with the protein surface. We further demonstrate a tendency for cations interacting with the protein surface to be least detrimental to enzymatic activity if they show a low polarizability when combined with small hydrophilic anions. We also find that the IL ion influence is not mitigated by the surplus of negatively charged residues of the halophilic enzyme. This is shown by free energy landscape analysis in root mean square deviation and distance variation plots of active site gating residues (Trp43 and His273) demonstrating no protection of specific structural elements relevant to preserving enzymatic activity. On the other hand, we observe a general effect across all IL systems that a tight binding of water at acidic residues is preferentially interrupted at these residues through the increased presence of potassium ions. Overall, this study demonstrates a co-ion interaction dependent influence on allosteric surface residues controlling the active/inactive conformation of halophilic alcohol dehydrogenase 2 and the necessity to engineer ionic liquid systems for enzymes that rely on the integrity of functional surface residues regardless of their halophilicity or thermophilicity for use in bioprocessing.

Reducing DNA Damage Associated with Endogenous Genotoxic Stress in Hematopoietic Stem Cells

Fanconi anemia (FA) is a bone marrow failure (BMF) syndrome that arises from mutations in a network of FA genes essential for DNA interstrand crosslink (ICL) repair and replication stress tolerance. Endogenous formaldehyde is ubiquitous within cells as it is produced as a byproduct during normal cellular metabolism such as histone, RNA and DNA demethylation. Previous studies show that endogenous formaldehyde is a hematopoietic stem cell (HSC) genotoxin and metabolic carcinogen. We previously showed that endogenous formaldehyde is removed by the enzyme alcohol dehydrogenase 5 (ADH5), and Adh5-deficient mice therefore accumulate formaldehyde adducts in DNA that require the FA pathway to repair. Mice lacking Adh5 together with the FA pathway central component Fancd2 exhibit bone marrow failure and early lethality. Adh5 haploinsufficiency combined with Fancd2 deficiency, or Fancd2 -/- Adh5 +/- mice, demonstrates severely compromised HSC activity. However, the contributing factors that cause DNA damage and the protective mechanisms by which cells reduce DNA damage during endogenous genotoxic stress are not fully understood. Here, we show that the genetic inactivation of Lnk/Sh2b3 in Fancd2 -/- Adh5 +/- mice restores HSC function. Adh5 haploinsufficiency exacerbated Fancd2 deficiency, while Lnk deficiency rescued HSC homeostasis and transplantability of Fancd2 -/- Adh5 +/- mice. Moreover, Lnk deficiency increased HSC quiescence and reduced endogenous DNA damage in Fancd2 -/- Adh5 +/- mice. Importantly, Lnk deficiency does not participate in repairing formaldehyde-induced DNA damage, nor does it metabolize formaldehyde or reduce genomic formaldehyde-deoxyguanine adduct in vivo. Rather, Lnk deficiency reduced single-strand DNA (ssDNA) breaks and ssDNA binding protein RPA in HSCs during the cell cycle, thereby suppressing the ATR pathway activation upon endogenous replication stress. Moreover, loss of Lnk increased S-phase progression and fork recovery in Fancd2 -/- Adh5 +/- HSPCs at the stressed replication fork upon HU treatment, thereby preventing replication fork collapse and DNA damage. These findings highlight a new mechanism by which Lnk deficiency mitigates replication stress-induced DNA damage in response to endogenous genotoxic insult from cellular metabolism during HSC regeneration.

Melatonin enhances the synthesis of volatile esters and lactones in apricot during low temperature storage

Low temperature storage often leads to chilling injury in apricots, causing a loss of aroma and a decrease in its commodity value. In this study, melatonin (MT, 0.1, 0.2, and 0.4 mmol L−1) dipping treatment was used to improve the aroma quality of apricot (‘Jintaiyang’ and ‘Pingdingxiang’) at low temperature (4 °C). Results demonstrated that the application of 0.2 mmol L−1 MT treatment effectively maintained firmness and soluble solids content (SSC), and inhibit the ethylene production and respiration rate of apricots. Additional observations revealed that MT was capable of inhibiting the activities of LOX (lipoxygenase), HPL (hydroperoxidelyase), and ADH (alcohol dehydrogenase) enzymes, thereby reducing the levels of alcohols and aldehydes in apricots. Conversely, MT upregulated the activities of LOX, HPL, ADH, ACX (acyl-CoA oxidase) and AAT (alcohol acyltransfera) enzymes, promoting the biosynthesis of lactones and esters in apricots. Thus, melatonin might be an effective method for low temperature storage of apricot by promoting the recovery of aroma substances.

Influence of Benzothiadiazole on the Accumulation and Metabolism of C6 Compounds in Cabernet Gernischt Grapes (Vitis vinifera L.).

Pre-harvest application of elicitors improves grape quality, specifically the phenolic compounds and color characteristics. Limited research has been conducted on the impact of elicitors on the C6 compounds found in grapes. This is due to lack of comprehensive studies examining the combined effects of bound aroma compounds, enzyme activity, and substrate availability. This study aimed to assess the impact of benzothiadiazole (BTH) on the physicochemical properties and C6 compounds of Cabernet Gernischt grapes during ripening. Compared with the control group (CK), BTH treatment significantly increased the 100-berry weight, skin/berry ratio, pH, total phenolic content, and total flavonoid content in ripe grapes. Additionally, BTH treatment led to significant reductions in reducing sugar, total soluble solids, titratable acidity, linoleic acid, linolenic acid, and free C6 aldehydes. Furthermore, BTH treatment significantly decreased the contents of free C6 alcohols and increased the levels of free and bound C6 esters. BTH treatment also increased the activities of lipoxygenase, alcohol dehydrogenase, and alcohol acetyltransferase enzymes, while it decreased the activity of hydroperoxide lyase enzyme. The application of BTH resulted in changes to the physicochemical properties and levels of C6 compounds in Cabernet Gernischt grapes by up-regulating enzyme activity and down-regulating precursors.

The role of PME and ADH enzymes in seed deterioration and its implication for producing high quality soybean seed

Soybean seeds are member of the orthodox seeds group which suseptable to deterioration. The low quality of soybean seeds used by farmers is one of the causes of the low soybean productivity at the farmer level. Pectin methylesterase (PME) and alcohol dehydrogenase (ADH) enzymes have been studied in relation to seed deterioration. Increase in seed moisture content is strongly suspected to be the initial occurrence and increase in PME enzyme activity which then followed by ADH enzyme activity in a series of biochemical reactions leading to the accumulation of acetaldehyde-protein adducts (APA) in soybean seeds. The APA contributes to deterioration of seeds. Thus, the increase in APA in soybean seeds may be used as an indicator of the level of deterioration of soybean seeds. Since high seed moisture content contributes to the initiation of PME activity in seeds, soybean seed production in the rainy season is not recommended because it will produce seeds with low physiological quality due to high PME activity so that the seeds cannot be stored for long-term period.

Waterlogging Tolerance of Actinidia valvata Dunn Is Associated with High Activities of Pyruvate Decarboxylase, Alcohol Dehydrogenase and Antioxidant Enzymes.

Kiwifruit (Actinidia spp.) is susceptible to waterlogging stress. Although abundant wild germplasm resources exist among Actinidia plants for improving the waterlogging tolerance of kiwifruit cultivars, the underlying mechanisms remain largely unknown. Here, a comparative study was undertaken using one wild germplasm, Maorenshen (A. valvata Dunn, MRS), and one cultivar, Miliang-1 (A. chinensis var. deliciosa (A.Chev.) A.Chev. cv. Miliang-1, ML). Under stress, the ML plantlets were seriously damaged with wilted chlorotic leaves and blackened rotten roots, whereas the symptoms of injury in the MRS plantlets were much fewer, along with higher photosynthetic rates, chlorophyll fluorescence characteristics and root activity under stress conditions. However, neither aerenchyma in the root nor adventitious roots appeared in both germplasms upon stress exposure. The activities of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH), as well as their transcript levels, were constitutively higher in MRS than those in ML under both normal and stress conditions. Waterlogging stress significantly enhanced the PDC and ADH enzyme activities in both germplasms, which were 60.8% and 22.4% higher in the MRS roots than those in the ML roots under waterlogging stress, respectively. Moreover, MRS displayed higher activities of antioxidant enzymes, including SOD, CAT, and APX, as well as DPPH-radical scavenging ability, and decreased H2O2 and MDA accumulation under both normal and stress conditions. Our findings suggest that the waterlogging tolerance of the wild A. valvata germplasm was associated with high PDC and ADH, as well as antioxidant ability.

Beneficial effects of WON-21 on the symptoms of a hangover and identification of active compounds: experimental studies on antioxidant, anti-inflammation, and alcohol-metabolizing enzymes

Many hangover cure products containing natural ingredients that are also effective against alcohol-related liver damage or improve liver function have recently become available. In addition to curing liver damage, antioxidants, anti-inflammatory agents, and blood ethanol reduction aids are emerging as relief targets that reduce hangover symptoms. We investigated the ameliorating effect of WON-21 herbal medicinal products by studying the mixing ratio of oriental medicine concept with respect to antioxidant potential, anti-inflammation, and aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) enzyme activities. WON-21 and its components exerted antioxidant and anti-inflammatory effects. Rutin, taxifolin, and quercetin showed superior antioxidant effects compared to the other components. WON-12 effectively reduced iNOS and COX-2 in LPS-stimulated macrophages. Quercetin and apigenin were 2 compounds effective for the inhibition of iNOS and COX-2. WON-21 and quercetin also significantly increased the activities of ALDH and ADH enzymes in a concentration-dependent manner.

Structure characterization and bioactivities of protein hydrolysates of chia seed expeller processed with different proteases in silico and in vitro

Chia seed (CS) expeller was hydrolyzed by 6 proteases (Alcalase, Neutrase, Protamex, Papain, Flavourzyme, Trypsin) in different hydrolytic patterns to improve bioavailability and explore the structure-enzyme active site relationship. At the meantime, in silico hydrolysis was performed to obtain a series of proteolytic sequences of chia seed protein treated by different enzymes. The hydrolysates of non-animal derived protease were further determined by in vitro experiment in terms of health-promoting activities. It is necessary to remove fiber before protease hydrolysis, and Alcalase and Flavorzyme had a good effect on the degradation of residual fiber of CS meal. Due to the diversity of enzyme cleave sites, the structure properties of hydrolysate treated by different proteases exhibited discrepancy. Furthermore, hydrolysates of CS meal presented varying bioactivity (antioxidant, hypoglycemic, hypotensive, hypolipidemic, anti-alcoholic activity). Among them, Neutrase, Protamex and Papain hydrolysis showed significant impact on the production of multiple active functional factors. The highest percentual of angiotensin I converting enzyme inhibitory (ACE) and alcohol dehydrogenase activation (ADH) effect were observed in Neutrase and Flavourzyme hydrolysates, with lowest IC50 of 0.219 ± 0.030 mg/mL and 0.047 ± 0.002 mg/mL, respectively. Ultimately, an activity-oriented protease screening method was obtained, which consists of in silico digestion and in vitro activity evaluation.

Screening and Optimization Consortium Technique of the Bacillus megatherium and Saccharomyces cerevisiae Microbial Consortium for Ethanol Detection

Determination of alcohol content is very important in the food and beverage industry. Biosensor is an alternative to measuring ethanol content. Alcohol biosensors with a single microbe still have a narrow measurement area at ethanol concentrations, so a microbial consortium is needed to widen the range of measured ethanol concentrations. Therefore, it is necessary to screen the microbes from Bacillus sp and S. cerevisiae which have the potential to produce alcohol dehydrogenase (ADH) enzymes and optimize the consortium technique that can provide the best response to oxidation currents. In the yeast microbial screening of 14 S. cerevisiae isolates and 5 Bacillus sp isolates, it can be concluded that for the 14 yeast S. cerevisiae isolates that have the potential to produce ADH enzymes, there is one isolate with the SCRF code. For the 5 bacterial isolates of Bacillus sp that have the potential to produce ADH enzymes, all Bacillus isolates with the code Bacillus megatherium 29/9/14, Bacillus megatherium 23/6/22, Bacillus 6, Bacillus 53, and Bacillus 55. Based on the oxidation current data, Bacillus megatherium 23 /6/22 produces the highest current compared to other Bacillus isolates. The consortium technique that provides the highest current is the method of mixing 1:1 (µL) microbial suspension in an Eppendorf container. Optimization of the consortium's biofilms using the Response Surface Method was produced at 10 days of age, pH 7.5, and 75 µL of microbial suspension dripping volume.

Sucrose Intake Elevates Erythritol in Plasma and Urine in Male Mice

BackgroundElevated serum erythritol concentration is a predictive biomarker of diabetes and cardiovascular incidence and complications. Erythritol is synthesized endogenously from glucose, but little is known regarding the origin of elevated circulating erythritol in vivo. ObjectivesIn vitro evidence indicates that intracellular erythritol is elevated by high-glucose cell culture conditions and that final step of erythritol synthesis is catalyzed by the enzymes sorbitol dehydrogenase (SORD) and alcohol dehydrogenase (ADH) 1. The purpose of this study was to determine whether dietary intake and/or diet-induced obesity affect erythritol synthesis in mice and whether this relationship is modified by the loss of the enzymes SORD or ADH1. MethodsFirst, 8-wk-old male Sord+/+, Sord−/−, Adh1+/+, and Adh1−/− mice were fed either low-fat diet (LFD) with 10% fat-derived calories or diet-induced obesity high-fat diet (HFD) with 60% fat-derived calories for 8 wk. Plasma and tissue erythritol concentrations were measured using gas chromatography–mass spectrometry. Second, male wild-type 8-wk-old C57BL/6J mice were fed LFD or HFD with plain drinking water or 30% sucrose water for 8 wk. Blood glucose and plasma and urinary erythritol concentrations were measured in nonfasted and fasted samples. Tissue erythritol was measured after killing. Finally, male Sord+/+ and Sord−/− mice were fed LFD with 30% sucrose water for 2 wk; then, nonfasted plasma, urine, and tissue erythritol concentrations were quantified. ResultsPlasma and tissue erythritol concentrations were not affected by loss of Sord or Adh1 in mice fed LFD or HFD. In wild-type mice, consumption of 30% sucrose water significantly elevated plasma and urinary erythritol concentrations on both LFD-fed and HFD-fed mice compared with that of plain water. Sord genotype did not affect plasma or urinary erythritol concentration in response to sucrose feeding, but Sord−/− mice had reduced kidney erythritol content compared with wild-type littermates in response to sucrose. ConclusionsSucrose intake, not HFD, elevates erythritol synthesis and excretion in mice. Loss of ADH1 or SORD does not significantly affect erythritol concentration in mice.

A pharmacophore-based approach to demonstrating the scope of alcohol dehydrogenases

Barriers to the ready adoption of biocatalysis into asymmetric synthesis for early stage medicinal chemistry are addressed, using ketone reduction by alcohol dehydrogenase as a model reaction. An efficient substrate screening approach is used to show the wide substrate scope of commercial alcohol dehydrogenase enzymes, with a high tolerance to chemical groups employed in drug discovery (heterocycle, trifluoromethyl and nitrile/nitro groups) observed. We use our screening data to build a preliminary predictive pharmacophore-based screening tool using Forge software, with a precision of 0.67/1, demonstrating the potential for developing substrate screening tools for commercially available enzymes without publicly available structures. We hope that this work will facilitate a culture shift towards adopting biocatalysis alongside traditional chemical catalytic methods in early stage drug discovery.

Effect of Methyl Jasmonate on the Biosynthesis of Volatile Compounds Associated with the Ripening of Grape Tomato Fruits

The present work aims to evaluate the roles of methyl jasmonate (MeJA) in the formation of volatile organic compounds (VOC) from grape tomatoes during ripening. Fruits were treated with MeJA, ethylene, 1-MCP (1-methylcyclopropene), and MeJA+1-MCP, with analyses of the VOC and levels of the gene transcripts for the enzymes lipoxygenase (LOX), alcohol dehydrogenase (ADH), and hydroperoxide lyase (HPL). An intimate relationship between MeJA and ethylene in aroma formation was detected, mainly among the VOC from the carotenoid pathway. Expression of the fatty acid transcripts, LOXC, ADH, and HPL pathway genes, was reduced by 1-MCP, even when associated with MeJA. In ripe tomato, MeJA increased most of the volatile C6 compounds, except 1-hexanol. The MeJA+1-MCP treatment followed most of the increases in volatile C6 compounds that were increased by MeJA alone, which evidenced some ethylene-independent mechanism in the production of the volatile C6 compounds. In ripe tomato, MeJA and MeJA+1-MCP increased the levels of 6-methyl-5-hepten-2-one, which is derived from lycopene, evidencing an ethylene-independent biosynthetic process.

The Nutrient Zinc in Soil and Plant: A Review

Zinc is an element found in low amounts in the soil, which may limit the development of agricultural crops. In addition, the absorption of this nutrient by plants is directly influenced by several factors such as: high pH, ​​amount of organic matter, high humidity associated with low temperatures and soil microbiota. Zinc is important for enzymatic activity, being a constituent part of the enzymes alcohol dehydrogenase, carbonic anhydrase, superoxide dismutase enzyme and polymer RNA, in addition to participating in the synthesis of precursor tryptophan in the metabolism of indoleacetic acid, which is a plant hormone directly related to the development of plants. In plants, the symptoms of zinc deficiency appear with the shortening of the internodes, reduction of the leaf area, reduction of its size, appearance of rosettes, chlorosis and necrosis. Thus, the objective of this review is to present the main aspects of the zinc nutrient in the soil and the functions performed in plants.