Identification and characterization of a novel 2R,3R-Butanediol dehydrogenase from Bacillus sp. DL01

Background2R,3R-butanediol dehydrogenase (R-BDH) and other BDHs contribute to metabolism of 3R/3S-Acetoin (3R/3S-AC) and 2,3-butanediol (2,3-BD), which are important bulk chemicals used in different industries. R-BDH is responsible for oxidizing the hydroxyl group at their (R) configuration. Bacillus species is a promising producer of 3R/3S-AC and 2,3-BD. In this study, R-bdh gene encoding R-BDH from Bacillus sp. DL01 was isolated, expressed and identified.ResultsR-BDH exerted reducing activities towards Diacetyl (DA) and 3R/3S-AC using NADH, and oxidizing activities towards 2R,3R-BD and Meso-BD using NAD⁺, while no activity was detected with 2S,3S-BD. The R-BDH showed its activity at a wide range of temperature (25°C to 65°C) and pH (5.0–8.0). The R-BDH activity was increased significantly by Cd²⁺ when DA, 3R/3S-AC, and Meso-BD were used as substrates, while Fe²⁺ enhanced the activity remarkably at 2R,3R-BD oxidation. Kinetic parameters of the R-BDH from Bacillus sp. DL01 showed the lowest K_m, the highest V_max, and the highest K_cat towards the racemic 3R/3S-AC substrate, also displayed low K_m towards 2R,3R-BD and Meso-BD when compared with other reported R-BDHs.ConclusionsThe R-BDH from Bacillus sp. DL01 was characterized as a novel R-BDH with high enantioselectivity for R-configuration. It considered NAD⁺ and Zn²⁺ dependant enzyme, with a significant affinity towards 3R/3S-AC, 2R,3R-BD, and Meso-BD substrates. Thus, R-BDH is providing an approach to regulate the production of 3R/3S-AC or 2,3-BD from Bacillus sp. DL01.How to cite: Elmahmoudy M, Elfeky N, Zhongji P, et al. Identification and characterization of a novel 2R,3R-Butanediol Dehydrogenase from Bacillus sp. DL01. Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.11.002     

Subtypes of ADH2 gene in alcoholics

Alocholism is the multifactorial disease influenced by genetic environmental interaction and genetic variation of the genes may be associated with alcohol dependence due to its modified function in behavioral and physiological responses. In the present study, genetic variation was detected in the subtypes of gene, coding for the alcohol metabolizing enzyme Alcohol Dehydrogenase 2 (ADH2). Blood samples were collected from the alcoholic and non alcoholic subjects and genotyping was performed using PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism), analysis to determine genetic polymorphisms in the ADH2 gene subtypes. The three subtypes of ADH2 gene (ADH2.1, ADH2.2 and ADH2.3) were found in both alcoholics (Family History Positive and Family History Negative) as well as non alcoholics.     

植物生理学部分实验材料的选择与培养

介绍了植物脱氢酶的组织化定位观察、硝酸还原酶活性的测定、糖与硼对花粉管生长的影响测定、钾离子对气孔开度影响材料的选择、低温对植物的伤害、叶绿体色素的提取及分离等实验的材料选择与培养.     

几种泥炭藓属植物乙醇脱氢酶同工酶分析

采用聚丙烯酰胺凝胶电泳对泥炭藓属植物5个种10个居群的乙醇脱氢酶同工酶进行分析,结果表明乙醇脱氢酶同工酶带共5条,ADH-5酶带明显,染色较深,说明酶活性较强,可以判断为共有特征带。泥炭藓有酶带1条,卵叶泥炭藓有酶带4条,加萨泥炭藓有酶带5条,多纹泥炭藓有酶带1条,尖叶泥炭藓有酶带3条,通过spss系统聚类表明泥炭藓属植物5个种中,泥炭藓和多纹泥炭藓与其余3个种存在明显的遗传差异。泥炭藓属植物种内遗传差异不明显。     

老年小鼠腹腔巨噬细胞激活后酶活性变化的实验研究

以肉汤培养基刺激小鼠腹腔巨噬细胞,三天后测定ACP、LDH和SDH活性变化,结果表明老年组受刺激后ACP、SDH活性升高水平较青年组差(P<0.05),老年组巨噬细胞应激能力低于青年组。     

环境氡所致肺剂量影响因素的实验研究

在环境氡水平的房间内，研究各种处理空气的方法所引起室内α潜能浓度、平衡因子、非结合态氡子体份额和气溶胶粒子数目及其大小分布的变化．计算支气管基底细胞层、肺区上皮及总肺的单位氡浓度年当量剂量，并与封闭房间未经任何空气处置的情况比较，结果显示：用正离子加风扇对流时总肺剂量率减少最为明显；而空调通风，对支气管剂量率的减少最为有效；吸烟或施放油烟，肺剂量都明显增加，油烟的影响尤为严重．     

Enzyme activity and myoglobin concentration in rat myocardium and skeletal muscles after passive intermittent simulated altitude exposure

Abstract

We studied the effect of intermittent hypobaric hypoxia exposure on lactate dehydrogenase and citrate synthase activities, together with myoglobin content, of rat myocardium, tibialis anterior, and diaphragm muscles. The intermittent hypoxia exposure programme consisted of daily 4-h sessions in a hypobaric chamber (5000 m) over a period of 22 days. Samples were taken at the end of the programme, and 20 and 40 days later, and compared with those of control animals. In myocardium, lactate dehydrogenase activity was significantly depressed in animals 20 days post-exposure (314.6 ± 15.3 IU · g^?1) compared with control animals (400 ± 14.3 IU · g^?1), while citrate synthase activity and myoglobin concentration showed a significant stepwise increase from control animals (88.2 ± 3.6 IU · g^?1 and 4.38 ± 0.13 μm · mg^?1) to animals 20 days (104.7 ± 3.7 IU · g^?1 and 5.01 ± 0.17 μm · mg^?1) and 40 days post-exposure (108.8 ± 6.5 IU · g^?1 and 5.11 ± 0.22 μm · mg^?1). In contrast, no differences were found in diaphragm and tibialis anterior muscles. Our results show that intermittent hypobaric hypoxia exposure increased the oxidative character of myocardium even 20 days after the hypoxic stimulus has ceased, and that this effect lasts for more than 40 days for citrate synthase activity and myoglobin concentration. These findings support our previous results on skeletal and cardiac muscle capillarization after passive intermittent simulated altitude exposure, thus providing morphofunctional and biochemical evidence for increased cardiac aerobic efficiency.     

Feasibility of eyes open alpha power training for mental enhancement in elite gymnasts

Abstract

This study focuses on a novel, easy to use and instruction-less method for mental training in athletes. Previous findings suggest that particular mental capacities are needed for achieving peak performance; including attentional control, focus, relaxation and positive affect. Electroencephalography (EEG) alpha brain activity has been associated with neural inhibition during processes of selective attention, for improving efficiency in information processing. Here we hypothesised that eyes open alpha power training by music teaches athletes to (1) learn to self-regulate their brain activity, and (2) learn to increase their baseline alpha power, herewith improving mental capacities such as focusing the allocation of attention. The study was double-blind and placebo-controlled. Twelve elite gymnasts were either given eyes open alpha power training or random beta power training (controls). Results indicate small improvements in sleep quality, mental and physical shape. In our first attempt at getting a grip on mental capacities in athletes, we think this novel training method can be promising. Because gymnastics is one of the most mentally demanding sports, we value even small benefits for the athlete and consider them indicative for future research.     

人参皂苷Rg1对β淀粉样肽诱导原代培养胎鼠皮质神经元损伤的保护作用

研究人参皂苷Rgl对β淀粉样肽诱导原代培养胎鼠皮质神经元损伤的保护作用。利用乳酸脱氢酶（LDH）测定试剂盒检测胎鼠皮质神经元培养液中LDH活力,并用四甲基偶氮唑蓝（MTT）比色法测定神经元存活率,观察人参皂苷Rg1对β淀粉样肽诱导原代培养胎鼠皮质神经元损伤的保护作用。结果显示：终浓度为5μmol／L、10μmol／L、15μmol／L的β淀粉样肽作用于皮质神经元48h后,培养液中LDH活力增高,神经细胞存活率下降,与不作任何处理的空白对照组比较,15μmol／L的β淀粉样肽组有显著性差异（P〈0．01）;经人参皂苷Rg1（20βLmol／L）预处理24h再加入15μmol／Lβ淀粉样肽作用48h,LDH活力下降,神经细胞的存活率升高,与仅加入15μLmol／Lβ淀粉样肽的损伤组比较差异显著（P〈0．01）。分析表明：人参皂苷Rg1能拮抗β淀粉样肽诱导的神经细胞损伤,对β淀粉样肽引起的神经细胞毒性有一定的保护作用。     

Adjustments of serum lactate dehydrogenase isoenzymes and their significance in monitoring the treatment in patients with tubercular pyothorax

The adjustments and diagnostic significance of polyacrylamide gel electrophoretic (PAGE) profiles of lactate dehydrogenase isoenzymes (LDH: 1.1.1.27) was evaluated in the sera and pleural fluid of patients with tubercular pyothorax. Sera and pleural fluid samples were randomly collected from 72 and 18 patients respectively at two different timings; first, when patients were admitted to the Hospital and second, after an intensive phase of treatment. Sera of 20 healthy individuals served as control. Our results demonstrate significant differences in sera LDH (sLDH) and pleural fluid LDH (pfLDH) isoenzymes. In patients the order of LDH isoenzyme in sera and pleural fluid followed: LDH−5>−4>−2>−3>−1 and LDH-5>−4>−3>−2>−1 respectively. The ranking of activity levels in control was LDH−2>−1>−3>−5>−4. In the second phase of sampling from 31 patients, values of sLDH isoenzymes showed recovery and resembled profiles of controls. Therefore, the sLDH zymograms of patients can be used as the prognostic marker, since they tend to reach the normal level during recovery signifying the effect of chemotherapy in hospitalized patients. Moreover, according to the present findings on LDH-PAGE profiles, the levels of LDH-5 and-4 rise in pyothorax patients significantly (P<0.05). This elevation along with the rise in total LDH activity may, therefore, be used in the diagnosis and monitoring of tubercular pyothorax.