酶法制备花生粕醒酒多肽

为更合理有效地利用花生粕资源,制备具有醒酒作用的花生粕多肽,本实验以Alcalase AF 2.4L蛋白酶酶法制备花生粕醒酒肽,经分级分离后,通过体外和动物实验验证其醒酒效果。结果表明,花生粕醒酒肽制备最佳工艺条件为：酶解时间3 h、酶解温度35 ℃、pH 9.5及料液比1∶30（m/V）。该条件下乙醇脱氢酶（alcoholdehydrogenase,ADH）激活率及多肽得率均较高。经分级分离后,分子质量在1 000～3 000 D的多肽对ADH激活作用最强,激活率为30.47%。G25凝胶色谱分析表明,花生粕多肽中小于3 000 D的多肽占89.55%,ADH激活率为29.25%。动物实验证明,花生粕多肽对小鼠有显著的防醉醒酒作用。小鼠血液乙醇含量测定结果表明,高剂量的花生粕多肽在60～90 min内能显著降低小鼠血液中的乙醇含量。     

Alcohol dehydrogenases that catalyse methyl formate synthesis participate in formaldehyde detoxification in the methylotrophic yeast Candida boidinii

Methyl formate synthesis during growth on methanol by methylotrophic yeasts has been considered to play a role in formaldehyde detoxification. An enzyme that catalyses methyl formate synthesis was purified from methylotrophic yeasts, and was suggested to belong to a family of alcohol dehydrogenases (ADHs). In this study we report the gene cloning and gene disruption analysis of three ADH-encoding genes in the methylotrophic yeast Candida boidinii (CbADH1, CbADH2 and CbADH3) in order to clarify the physiological role of methyl formate synthesis. From the primary structures of these three genes, CbAdh1 was shown to be cytosolic and CbAdh2 and CbAdh3 were mitochondrial enzymes. Gene products of CbADH1, CbADH2 and CbADH3 expressed in Escherichia coli showed both ADH- and methyl formate-synthesizing activities. The results of gene-disruption analyses suggested that methyl formate synthesis was mainly catalysed by a cytosolic ADH (CbAdh1), and this enzyme contributed to formaldehyde detoxification through glutathione-independent formaldehyde oxidation during growth on methanol by methylotrophic yeasts.     

细菌Enterobacter dissolvens的直流电解刺激过程

以葡萄糖为唯一碳源,研究了细菌Enterobacter dissolvens在直流电条件下的生长和代谢过程. 实验结果表明,当使用盐桥屏蔽电极反应时,细胞生长曲线和葡萄糖代谢速率基本不受电流强度的影响,而当采用铂丝电极时,反应体系中发生水解反应,采用10 mA电流通电12 h后,菌液中细胞的脱氢酶比活力和葡萄糖降解率分别为对照的1.98倍和1.48倍,细胞生长亦有所加快,但在其活力下降时出现大量死亡. 扫描电镜照片显示细胞结构受到明显破坏,并发生细胞膜穿孔现象,这表明可能受到了过氧化氢等阳极水解中间产物的刺激作用.     

纤维二糖脱氢酶的研究进展

纤维二糖脱氢酶(CDH)是由白腐菌、软腐菌及褐腐菌等真菌产生的一种木材降解菌。本文综述了CDH对糖的专一性及与纤维素的相互作用、CDH的酶反应机制和动力学及国内外的CDH的最新应用领域。     

大肠杆菌丙酮酸脱氢酶的克隆与表达优化

为了在大肠杆菌中表达大肠杆菌丙酮酸脱氢酶,用PCR法从大肠杆菌总DNA中克隆了pdc基因,将其插入载体pGEX-KG后转化大肠杆菌BL21(DE3),在IPTG的诱导下实现了表达.通过对表达条件的优化,在TB M9(1∶1)培养基中,33℃下使用终浓度0.5 g·L-1的乳糖诱导4 h,重组大肠杆菌丙酮酸脱氢酶的表达量可占全菌蛋白的45%左右,比未优化前提高了约20%,同时大大降低了成本.     

An immuno-wall microdevice exhibits rapid and sensitive detection of IDH1-R132H mutation specific to grade II and III gliomas

World Health Organization grade II and III gliomas most frequently occur in the central nervous system (CNS) in adults. Gliomas are not circumscribed; tumor edges are irregular and consist of tumor cells, normal brain tissue, and hyperplastic reactive glial cells. Therefore, the tumors are not fully resectable, resulting in recurrence, malignant progression, and eventual death. Approximately 69–80% of grade II and III gliomas harbor mutations in the isocitrate dehydrogenase 1 gene (IDH1), of which 83–90% are found to be the IDH1-R132H mutation. Detection of the IDH1-R132H mutation should help in the differential diagnosis of grade II and III gliomas from other types of CNS tumors and help determine the boundary between the tumor and normal brain tissue. In this study, we established a highly sensitive antibody-based device, referred to as the immuno-wall, to detect the IDH1-R132H mutation in gliomas. The immuno-wall causes an immunoreaction in microchannels fabricated using a photo-polymerizing polymer. This microdevice enables the analysis of the IDH1 status with a small sample within 15 min with substantially high sensitivity. Our results suggested that 10% content of the IDH1-R132H mutation in a sample of 0.33 μl volume, with 500 ng protein, or from 500 cells is theoretically sufficient for the analysis. The immuno-wall device will enable the rapid and highly sensitive detection of the IDH1-R132H mutation in routine clinical practice.     

Inhibition of Staphylococcus aureus by Phenolic Phytochemicals of Selected Clonal Herbs Species of Lamiaceae Family and Likely Mode of Action through Proline Oxidation

Staphylococcus aureus, a Gram-positive organism, is responsible for numerous infections ranging in severity from skin and soft tissue infections to endocarditis and septic arthritis. Further, Staphylococcal food poisoning (SFP) caused by enterotoxigenic staphylococci is one of the main food-borne diseases. In this study, several single-seed origin clonal lines of herbs from Lamiaceae family were screened for antimicrobial applications against S. aureus. These clonal lines have consistent total phenolic content, phenolic profile and antioxidant activity as opposed to heterogenous phenolic profiles of typical herbal extracts. The clonal extracts of specific herb species were evaluated for anti- S. aureus activity. Water extracts of clonal lemon balm had the highest anti- S. aureus activity followed by clonal extracts of rosemary RoLA, sage, oregano, rosemary Ro-6, rosemary RoK-2 and chocolate mint. The anti- S. aureus activity of the water extracts correlated with gallic acid and caffeic acid content, which in pure form showed high anti- S. aureus activity. Based on the rationale that gallic acid and caffeic acid were likely proline analogs affecting proline oxidation, the countering effect of proline to overcome their anti- S. aureus activity was evaluated. Results indicated proline can overcome the inhibitory effects of gallic acid and caffeic acid. These results point to the likely role of phenolic oxidation via proline dehydrogenase, which could be an important target for inhibition by phenolic phytochemicals behaving as proline analog mimics. This mode of regulation by phenolics at the bacterial proline dehydrogenase in the plasma membrane may be an important antimicrobial defense in plants and has consequences for disruption of critical energy metabolism of invading bacterial pathogen. This rationale could be used to design new antimicrobial strategies against S. aureus and other relevant bacterial pathogens.     

Acetic acid removal by Saccharomyces cerevisiae during fermentation in oenological conditions. Metabolic consequences

The commercial Saccharomyces cerevisiae strains used in champagne winemaking were tested for their ability to metabolise acetic acid during alcoholic fermentation. Fermentation tests were performed in conditions close to oenological ones using a Chardonnay grape juice supplemented with acetic acid. The amount of acetic acid metabolised by wine yeast increased with increasing initial acetic acid concentration and this elimination occurred during the second part of the exponential growth phase. When the initial acetic acid concentration exceeds 1 g/l, and whatever the yeast strain used, the concentration of acetic acid in the resulting wine cannot be reduced to an acceptable level according to the current legislation. Acetic acid removal modified yeast metabolism, since more acetaldehyde, less glycerol and less succinic acid were produced. Considering the reduction of the NADPH/NADP⁺ ratio following acetic acid consumption, we propose, as a new hypothesis, that acetic acid could modify yeast metabolism by reducing the activity of the NADP⁺ dependent aldehyde dehydrogenase Ald6p.     

温度对提高活性污泥法处理含酚废水效率的研究与应用

本文从生化反应动力学理论出发讨论了温度与生化反应速率的相关作用，重点研究了温度对脱氢酶活性的影响，回归出脱氢酶反应速度的Ａｒｒｈｅｎｉｕｓ表达式，并给出了活性污泥法在脱酚装置中高温驯化的应用实例及运行效益分析。     

少根根霉发酵糖质原料积累

少根根霉Ｒ＿３０菌株摇瓶发酵过程中的酶活分析及间接实验表明：Ｌ－苹果酸积累的关键酶是苹果酸脱氢酶（Ｅ．Ｃ．１．１．１．３７），Ｒ＿３０菌株的Ｌ－苹果酸积累主要是通过草酰乙酸还原及丙酮酸羧化，ＴＣＡ循环及乙醛酸循环主要用于维持菌体的正常代谢．