桑葚抗酒精性肝损伤活性部位筛选研究

为探讨桑葚鲜果的抗酒精性肝损伤作用,通过采用瓦勒-霍赫法(ValleHoch)体外测定桑葚鲜果醇提物和水提物对乙醇脱氢酶的影响。桑葚鲜果的乙醇、甲醇和水的提取物对乙醇脱氢酶都有不同程度的激活作用,激活率分别为89.34%、60.56%和135.45%,其中桑葚的水提取物效果最佳。     

酵母醇脱氢酶的分离纯化

报道了酵母醇脱氢酶的分离纯化，使用硫酸铵分级沉淀，SephadexG—100凝胶层析技术，从啤酒酵母提取液中分离出醇脱氢酶，收得率为10．9％，纯化倍数达53．2。     

壳聚糖固定化乙醇脱氢酶的酶学性质研究

以壳聚糖作载体,戊二醛作交联剂,并以游离的乙醇脱氢酶作为对照,对壳聚糖固定化乙醇脱氢酶的酶学性质进行研究.结果表明,当戊二醛浓度为0.6%(v/v),交联时间为6 h时,壳聚糖固定化乙醇脱氢酶对温度、碱性环境以及金属离子Cu~(2+)溶液的耐受性均明显增强,且操作稳定性明显提高.     

异硫氰酸酯法固定化醇脱氢酶乳酸脱氢酶和辅酶Ⅰ

本文探索了一条较为简便、实用的制备异硫氰酸酯活性载体的新方法,研究了用异硫氰酸酯共价法固定化醇脱氨酶、乳酸脱氢酶和辅酶Ⅰ的条件,并对三者进行了共固定化。按本实验方法得到的固定化醇脱氢酶和乳酸脱氢酶的活力回收可达8.9%和11.9%,得到的固定化三元全酶系统的辅酶再生能力为相应游离酶系统的4倍。     

从微生物细胞提取ADH的探讨

讨论了从醋酸杆菌发酵中提取ＡＤＨ以及从酵母细胞中提取ＡＤＨ的可能性。在一定的ｐＨ及酶解时间内，醋酸杆菌细胞内ＡＤＨ活性很低，而酵母细胞内ＡＤＨ活性相对较高。     

Exo-celiac liver in Glyptosternum maculatum

A unique structure in the fish of Glyptosternum maculatum(Regan)(Siluriformes:Sisoridae)is reported.It was identified as a part of the liver named "exo-celiac liver".This new organ is located between skin and muscle and connected with the celiac liver by a funiform tissue,"joint belt".It has similar histological features and isozyme electrophoretogramic bands of lactate dehydrogenase,esterase,malate dehydrogenase and alcohol dehydrogenase as in the celiac liver.This unique organ has biological research value and could serve as an important tool for studying organogenesis and evolution.     

冬春性小麦杂交组合苗期同工酶研究

运用垂直管状聚丙烯酸胺凝胶电泳方法,对7个冬春性小麦杂交组合和1个87—11硬粒小麦与北川2号普通小麦杂交组合分蘖盛期的叶片过氧化物酶,乙醇脱氢酶及淀粉酶同工酶进行分析,结果表明,各杂交组合的F_1代苗期叶片过氧化物酶和淀粉酶酶带与亲本显著不同.杂种中有新酶带出现,有些带表现为互补带,有些带为双亲所没有,而有些带则消失.乙醇脱氢酶在亲本及杂种中均有两条酶带,但酶带活性差异很大,杂种的酶谱与形状所反映出的杂种优势有一定的关系.     

糖蜜发酵过程中乙醇脱氢酶对发酵效率的影响

在用糖蜜为原料的酒精发酵生产过程中,通过气象色谱仪测出发酵环境中有大量乙醛的存在,同时酒精浓度也一直偏低.于是通过对发酵温度,pH和去除金属离子等因素做出调整,研究乙醇脱氢酶对发酵结果的影响.结果表明乙醇脱氢酶活性会对发酵效率产生影响.     

Salt tolerance of transgenic rice (Oryza sativa L.) with mtlD gene and gutD gene

Southern blot analysis indicated that mtlD gene (encoding mannitol-1-phosphate dehydrogenase) and gutD gene (encoding glucitol-6-phosphate dehydrogenase) had been integrated into the rice genome mediated by Agrobacterium tumefaciens LBA4404(pBIGM). The expression of the above two genes in transgenic rice plants was demonstrated by Northern blot analysis and enzymatic activity assay. Analysis of sugar alcohol showed that transgenic rice plants could produce and accumulate mannitol and sorbitol. The salt tolerance of transgenic plants was much higher than that of their controls.     

Production of yeast alcohol dehydrogenase isoenzymes by selection.

Mutants of yeast alcohol dehydrogenase have been produced that protect the cell against the poisonous aldehyde acrolein by increasing the NADH-NAD ratio. The altered properties include changes both in binding constants and in cooperativity. Such mutants may be useful in exploring the nature of adaptation at the molecular level.     

Conservation and change in the DNA sequences coding for alcohol dehydrogenase in sibling species of Drosophila

The DNA sequences of the alcohol dehydrogenase (Adh) genes of four very closely related species of Drosophila show that the rates of nucleotide change vary greatly in different functional domains of this gene. A phylogeny of these species based on the Adh sequence data is consistent with that based on polytene chromosome banding patterns.     

Salt tolerance of transgenic rice (Oryza sativa L.) withmtlD gene andgutD gene

Southern blot analysis indicated thatmtlD gene (encoding mannitol-1-phosphate dehydrogenase) andgutD gene (encoding glucitol-6-phosphate dehydrogenase) had been integrated into the rice genome mediated byAgrobacterium tumefaciens LBA4404(pBIGM). The expression of the above two genes in transgenic rice plants was demonstrated by Northern blot analysis and enzymatic activity assay. Analysis of sugar alcohol showed that transgenic rice plants could produce and accumulate mannitol and sorbitol. The salt tolerance of transgenic plants was much higher than that of their controls.     

重组Pichia酵母(Muts)发酵过渡阶段关键酶活分析

重组Pichia酵母表达系统的发酵存在从利用甘油为碳源生长到利用甲醇为碳源表达外源蛋白的发酵表达过渡阶段。Pichia酵母过渡阶段碳源代谢途径关键酶酶活分析表明：甲醇诱导3h AOX2酶活为0,4h时突然增加到0．05U,继续诱导,酶活缓慢增加;在过渡阶段甲醛脱氢酶和6-P-葡萄糖脱氢酶分别增加了6．1倍、2．5倍,而丙酮酸脱氢酶和异柠檬酸脱氢酶分别下降为原酶活的29．4％及16．4％,表明甲醇诱导后甲醇完全氧化代谢途径得到强化,而糖酵解途径和三羧酸循环途径代谢作用减弱。     

嗜热厌氧产乙醇杆菌乙醇代谢途径的初步研究

以乙醇产量和细胞密度的提高为目标,从碳源和氮源入手,对嗜热厌氧产乙醇杆菌THermoanaerobacter ethanolicus JW200的培养基作了初步优化以提高乙醇代谢途径中的关键酶的得率,便于提纯.葡萄糖浓度的提高对乙醇的产生有明显的诱导作用,但当葡萄糖浓度高于2%,乙醇产量反而下降.酵母粉对乙醇产量没有促进作用,单纯提高酵母粉浓度对细胞密度无显著影响,而同时提高葡萄糖和酵母粉浓度至2.0%,OD600最高可达2.0.2%葡萄糖,0.5%酵母粉对单位细胞乙醇产量的诱导效果最佳.T.ethanolicusJW200粗酶液中未检测到丙酮酸脱羧酶的活性,经亲和柱Cibacron Blue-3GA部分纯化,在NAD洗脱蛋白中检测到辅酶A依赖型乙醛脱氢酶的活性,表明辅酶A依赖型乙醛脱氢酶是该菌乙醇代谢途径中的关键酶,它和乙醇脱氢酶共同作用,将乙酰辅酶A转化成乙醇.     

涡虫再生过程中乳酸脱氢酶同工酶变化分析

采用聚丙烯酰胺不连续凝胶垂直板活性电泳技术,分析了涡虫切割后再生过程中乳酸脱氢酶同工酶的变化.结果表明:在涡虫去头后再生(第1 d至第7 d)过程中乳酸脱氢酶的表达存在差异,同一种酶在再生不同时期表达量不同,不同种酶在同一时期的表达量也不相同.     

不同基因型的人类乙醛脱氢酶2基因的克隆及表达

乙醛脱氢酶2是细胞防御系统的重要组成部分,它催化各种对人体有害的醛类成相应的酸．实验证明,东亚人群中存在大量的突变基因型aldh2*2,且aldh2*2基因型与酒后宿醉程度(脸红及不适感)相关．本实验采用昆虫细胞表达系统sf9高效表达ALDH2和ALDH2*2,并分别检测两种蛋白对底物乙醛的催化活性,发现二者对乙醛的催化活性差异显著,其中ALDH2的Km为1．70μmol／L,而ALDH2*2的Km为61．56μmol／L,支持了前人关于ALDH2的遗传缺陷可能导致醉酒及酒后不适感的结论．     

大鼠亚急性酒精性肝损伤模型的建立

目的 本研究参照国内学者一些造模方法,结合人体食用方式和饮酒习惯,通过对比饮用不同酒精剂量、不同饮用时间得出建立酒精性肝损伤的最易条件。方法 选用SPF级雌性Wistar大鼠(初始体质量150～180 g)30只,随机分为模型组和对照组。模型组分别给予酒精含量为15%、30%的普通白酒,对照组给予蒸馏水,以15 mL/kg·BW经口灌胃方式给予,试验周期分为8周。实验结束时从大鼠眼眶静脉丛采血,测定血清中谷氨酸氨基转移酶(ALT)、天门冬氨基酸转移酶(AST)、乙醇脱氢酶(ADH);取肝脏,测定肝脏组织MDA、SOD、GSH、TG及肝脏组织病理学损伤。结果 结果显示, MDA 30%酒精组与空白对照组比较有显著性差异(P0.05)。模型组大鼠血脂代谢紊乱、肝内脂肪蓄积,病理组织学检查可见弥漫性的肝细胞脂肪变性,细胞内可见大小不等的脂肪滴,从肝脏病变得分来看,15%酒精组、30%酒精组肝组织脂肪变性程度与空白对照组比较,有显著性差异(P<0.01, P<0.01)。结论 大鼠经口灌胃给予30%的普通白酒8周,可致肝损伤,结果可重复,成功建立了大鼠亚急性酒精性肝损伤的动物模型。     

1,3-丙二醇脱氢酶三级结构的模建

利用生物大分子数据库及生物信息学技术,对来源于Klebsiella pneumoniae的1,3-丙二醇脱氢酶分子进行二级结构预测、多序列联配．实验发现,其具有较保守的铁离子结合位点,而未发现常见的NAD(H)结合位点．在此基础上,利用同源建模法和穿线法模建该酶的三级结构,进一步发现铁离子结合位点在空间上形成一口袋状结构．探讨对其作用机制,同时发现该序列中存在2个含铁元素的乙醇脱氢酶信号．     

反胶束固定化醇脱氢酶的制备

报道了用反胶束体系固定化醇脱氢酶(ADH)的研究.在此体系中,以十六烷基三甲基溴化铵(CTAB)作为表面活性剂,辛烷和己醇作为溶剂及助溶剂.考察了ADH固定化的影响因素,确立了最佳固定化条件:含水量w0即cH2O/cCTAB为13,酶液pH值为7.8,CATB浓度为0.35 mol/L,己醇浓度为13%.     

Alcohol dehydrogenase activity in cultured cells from different tobacco (Nicotiana tabacum L.) varieties

The activity of alcohol dehydrogenase (ADH) in cultured cells of various tobacco was determined. It was found that significant differences existed in cells of different varieties cultured under normal conditions and as well after treated with exogenous ethanol. The ADH activity had positive relation with the ability of the cells to catabolize exogenous ethanol, indicating that the main function of the ADH in tobacco cells was in the direction of converting ethanol to acetaldehyde. Foundation item: Supported by the Natural Science Foundation of Guandong Province. (No. 950406) Biography: Zheng ling (1974-), female, Master student.