Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmo- spheric carbon dioxide by photosynthesis. Genetic manip- ulation has increased the variety of chemicals that cyanobact...Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmo- spheric carbon dioxide by photosynthesis. Genetic manip- ulation has increased the variety of chemicals that cyanobacteria can produce. However, their uniquely abundant NADPH-pool, in other words insufficient supply of NADH, tends to limit their production yields in case of utilizing NADH-dependent enzyme, which is quite common in heterotrophic microbes. To overcome this cofactor imbalance and enhance cyanobacterial fuel and chemical production, various approaches for cofactor engineering have been employed. In this review, we focus on three approaches： （1） utilization of NADPH- dependent enzymes, （2） increasing NADH production, and （3） changing cofactor specificity of NADH-dependent enzymes from NADH to NADPH.展开更多
0 前言随着瘦肉型猪在生产上的推广,P.S.E.猪(Pale,Soft and Exudative pigs)在经济上造成的损失也越来越大。七十年代以后,国内、外在对瘦肉型猪选育的同时,广泛开展了对肉质的研究。猪体内酶活性变化与肉质、肉量关系的研究也受到重视...0 前言随着瘦肉型猪在生产上的推广,P.S.E.猪(Pale,Soft and Exudative pigs)在经济上造成的损失也越来越大。七十年代以后,国内、外在对瘦肉型猪选育的同时,广泛开展了对肉质的研究。猪体内酶活性变化与肉质、肉量关系的研究也受到重视。P.S.E.肉在瘦肉率高的猪中多发;其红细胞易于溶血,肌细胞膜易于受损,破裂;糖代谢活动紊乱等,这似乎都与体内NADPH生成酶活性有关。因此,特作本试验。1 材料与方法1987年春,用ES猪53头。其中:公猪31头,母猪22头。出生年龄差别在20天以内。试猪三月龄时,采血用荧光分光光度法测定苹果酸酶(ME),葡萄糖-6-磷酸脱氢酶(G6PD)和6-磷酸葡萄糖酸脱氢酶(6PGD)三种NADPH生成酶的活性。然后进行氟烷测定。试猪六月龄时,电击后再测血中ME的活性。宰后测定肌肉中ME、G6PD和6PGD三种酶活性。并测定背最长肌的pH值、肉色值和系水力值,算出肉质模糊综合评定值(FSD值)。展开更多
文摘目的:研究两种剂型通络方剂(超微粉和微粉)对糖尿病SD大鼠肾脏氧化应激的影响。方法:链脲佐菌素(60 mg/kg)腹腔注射诱导糖尿病大鼠。1周后测血糖≥16.7 mmol/L为糖尿病,将大鼠随机分为糖尿病对照组(DMC,n=7)、通络方剂超微粉组(DM+UT,n=8)和通络方剂微粉组(DM+FT,n=8)3组,同时取8只大鼠作为正常对照组(NC)。DM+UT组和DM+FT组按每天1 g/kg UT或FT灌胃,NC和DMC组给予等量的生理盐水溶液。干预4周后,测肾质量/体质量(KW/BW)和24 h尿蛋白(24 h UP),比色法检测肾皮质抗氧化酶和丙二醛(MDA),实时PCR法检测NADPH氧化酶亚基p47phox和p22phox mRNA表达的改变。结果:与正常大鼠相比,糖尿病大鼠肾皮质MDA含量、24 h UP和KW/BW升高,总超氧化物歧化酶(TSOD)活性降低,谷胱甘肽过氧化物酶(GSH-Px)活性升高,均有统计学意义;正常大鼠与糖尿病大鼠间过氧化氢酶(CAT)活性差异无统计学意义。与DMC组相比,两个通络方剂干预组糖尿病大鼠肾皮质MDA、24 h UP和KW/BW明显降低;TSOD和GSH-Px活性增强,差异均有统计学意义。DMC组和两个通络方剂组间CAT活性差异无统计学意义。其中DM+UT组对24 h UP、KW/BW、MDA、TSOD和GSH-Px的作用较DM+FT组更明显,差异有统计学意义。与正常大鼠相比,糖尿病大鼠肾皮质NADPH氧化酶亚基p47phox mRNA表达增强,差异有统计学意义。与DMC组相比,两个通络方剂干预组p47phox mRNA表达降低,差异有统计学意义,但两干预组间差异无统计学意义。在各实验组间NADPH氧化酶亚基p22phox mRNA表达的差异无统计学意义。结论:通络方剂能增强糖尿病大鼠肾脏TSOD和GSH-Px活性,降低NADPH氧化酶p47phox mRNA的表达,可能因此抑制肾脏氧化应激水平,减轻糖尿病大鼠早期的肾脏损伤。
文摘Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmo- spheric carbon dioxide by photosynthesis. Genetic manip- ulation has increased the variety of chemicals that cyanobacteria can produce. However, their uniquely abundant NADPH-pool, in other words insufficient supply of NADH, tends to limit their production yields in case of utilizing NADH-dependent enzyme, which is quite common in heterotrophic microbes. To overcome this cofactor imbalance and enhance cyanobacterial fuel and chemical production, various approaches for cofactor engineering have been employed. In this review, we focus on three approaches： （1） utilization of NADPH- dependent enzymes, （2） increasing NADH production, and （3） changing cofactor specificity of NADH-dependent enzymes from NADH to NADPH.
