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991.
992.
【目的】体外转录并纯化酵母端粒酶RNA,明确缓冲液中组分对其构型的影响,初步研究四膜虫端粒酶相关蛋白p65与酵母端粒酶RNA的结合情况,为酵母端粒酶活性鉴定及构型功能研究奠定基础。【方法】利用核酶的自剪切功能,通过在3′端引入HDV核酶序列获得完整的酵母端粒酶RNA;并用分子筛SuperDeX-200/16/60凝胶过滤纯化酵母端粒酶RNA;琼脂糖凝胶电泳检测RNA Buffer组分中NaCl和MgCl2浓度对酵母端粒酶RNA构型的影响;非变性聚丙烯酰胺凝胶电泳(PAGE)检测四膜虫端粒酶相关蛋白p65与酵母端粒酶RNA的结合情况。【结果】通过基因序列合成,结合PCR扩增方法获得了酵母端粒酶RNA基因,并将其构建到体外转录载体上;体外转录获得大量的酵母端粒酶RNA(Yeast-RNA-239);使用SuperDeX-200/16/60成功分离得到了纯净的Yeast-RNA-239。NaCl、MgCl2浓度对酵母端粒酶RNA构型有一定的影响,表现为没有NaCl或MgCl2时,RNA的构型均一且致密;随NaCl、MgCl2浓度的增大,RNA构型逐渐变得松散;而四膜虫端粒酶相关蛋白p65能与酵母端粒酶RNA有效结合。【结论】在体外成功制备了高纯度的酵母端粒酶RNA,NaCl、MgCl2浓度对其构型有影响,四膜虫端粒酶相关蛋白p65能够帮助端粒酶RNA正确折叠。 相似文献
993.
Cu2+对克氏原螯虾(Procambarus clarkii)肝胰腺的蛋白质氧化损伤效应 总被引:1,自引:0,他引:1
克氏原螯虾(Procambarus clarkii)是一种潜在的水质环境污染的指示生物,为研究水体中不同浓度的重金属Cu2+对其肝胰腺组织的蛋白质氧化损伤作用,在测得Cu2+致克氏原螯虾96 hLC50为30 mg·L-1后,将螯虾分别暴露于0、0.5、1.0、3.0、5.0、10.0 mg·L-1的Cu2+溶液中,并在暴露24、48、72、96 h后测定各处理组肝胰腺组织的活性氧自由基(ROS)、总抗氧化能力(T-AOC)、谷胱甘肽过氧化物酶(GSH-PX)活性、蛋白质羰基(PCO)含量以及DNA-蛋白质交联(DPC)系数。结果表明,在暴露24h时,随着Cu2+浓度的升高,ROS、T-AOC和GSH-PX水平的变化规律相似,均为先上升后下降,PCO含量和DPC系数随暴露浓度的升高而增加;在暴露48、72、96 h后,ROS、T-AOC、PCO水平和DPC系数均表现为先升后降的趋势,GSH-PX活性在染毒96 h后,随着浓度的升高而下降。PCO含量的变化具有一定的剂量-效应关系。结果提示,肝胰腺的蛋白质氧化损伤可能是重金属Cu2+致克氏原螯虾毒性效应的主要机制之一。 相似文献
994.
以14个苦瓜(白苦瓜、绿苦瓜和广西野生苦瓜)高世代自交系,配制出14个杂交组合,进行了苦瓜数量性状、蛋白质和ISSR分子标记3种遗传距离分析以及3种遗传距离与杂种优势之间关系的分析.结果表明:数量性状与蛋白质、ISSR分子标记遗传距离之间相关系数分别为0.8340和0.4532;蛋白质遗传距离与ISSR分子标记遗传距离的相关系数为0.5940;数量性状与蛋白质遗传距离与产量杂种优势之间均呈极显著直线回归关系;而ISSR分子标记遗传距离与产量杂种优势之间呈显著直线回归关系. 相似文献
995.
为探究不同冷冻解冻方法对猪精子损伤的影响,采用2种常用的冷冻解冻方法处理猪精子,分别对其顶体膜蛋白进行分离,进行SDS-PAGE电泳和总灰度值的检测和分析。结果表明,采用一次稀释法进行猪精液的冷冻保存较二次稀释法解冻后精子活率高,精子顶体膜蛋白组分中除125 ku和90 ku处蛋白表达水平低于二次稀释法外,120 ku、48 ku、36 ku均高于二次稀释法。可见,猪精子在受到更深层次(二次稀释法对精子冷冻解冻损伤大)的冷冻损伤时,伴随着顶体膜蛋白125 ku和90 ku表达水平的升高以及120、48及36 ku表达水平的降低。 相似文献
996.
In this experiment, 23% of fish meal protein was replaced with protein from Australian soybean meal (SBM), lupin meal (LM), corn gluten meal (CGM) and meat meal (MM) in nutritionally balanced experimental diets. Growth and growth efficiencies of juvenile Australian short‐finned eel Anguilla australis australis (Richardson) elvers (2.23±0.4‐g average wet weight) were compared. Elvers were fed twice a day to a total of 5% body weight per day for 63 days. Total weight gain (g), specific growth rate (% day?1), protein efficiency ratio (%) and productive protein value (%) were significantly higher (P<0.05) for elvers fed the MM diet than for those fed the LM diet. There were no differences in diurnal ammonia‐nitrogen excretion rates. However, diurnal urea‐nitrogen excretion rates were significantly (P<0.05) affected by diet and rates were two to three times higher for all diets, except CGM, 4 h following the afternoon feed. Diet significantly affected apparent digestibility (AD); ADs of protein for SBM and LM were significantly (P<0.001) higher than for control diet, CGM and MM; AD of energy for LM was significantly (P<0.05) lower than for all the other diets. Fish meal protein was replaced by CGM, SBM and MM without compromising growth rates of the Australian short‐finned eel. However, whole lupin seed meal (LM) depressed growth and growth efficiencies most likely because of the high indigestible carbohydrate content. 相似文献
997.
Two experiments were conducted to measure the apparent digestibility coefficients (ADCs) of nutrients, dry matter, and energy in by‐products of the brewing industry and in selected animal protein ingredients for rainbow trout. In experiment 1, 500 rainbow trout (average body weight 170.8±5.5 g) were stocked in ten 140‐L digestibility tanks with 50 fish per tank and two tanks per diet. Yttrium oxide was used as an inert marker in the diets. The high fibre content of brewer's dried grains (BDG) affected the ADCs of dry matter but not of protein or amino acids. Brewer's dried yeast had a higher protein content than BDG, but ADC values for protein and amino acids were significantly lower. The ADCs of phosphorus were similar among brewer's dried products. The BDG high‐protein, fraction had marginally higher ADC values for dry matter, protein and amino acids than regular BDG. Conditions in experiment 2 were similar to those in experiment 1. ADC values for spray‐dried porcine plasma were over 98% for dry matter, crude protein, crude fat, and gross energy. ADC values for spent hen meal were higher than those of poultry by‐product meal or feather meal, with the exception of gross energy. However, spent hen meal was unpalatable. The ADCs in these ingredients were variable, and this variability must be taken into account when these ingredients are formulated into feeds for fish. 相似文献
998.
Dietary protein/energy ratios for Atlantic salmon in relation to fish size: growth, feed utilization and slaughter quality 总被引:3,自引:0,他引:3
Four extruded diets differing in protein/fat concentrations, 378/389 g kg?1, 425/346 g kg?1, 480/308 g kg?1 and 524/256 g kg?1 were tested in a digestibility trial and a growth study. Apparent digestibility of protein and fat were not significantly different among the diets when tested in 1-kg Atlantic salmon, Salmo salar L., in sea water. The diets represented a range of digestible protein to digestible energy ratios (DP/DE ratios) of 14.1, 16.4, 18.8 and 21.9 g MJ?1. The 138-day growth study was performed with triplicate groups of Atlantic salmon of 1.0 and 2.5 kg initial weight. Irrespective of size; growth, feed conversion ratio (FCR), nitrogen and energy retention were poorer in fish fed the diet with DP/DE ratio of 14.1 g MJ?1 compared with the fish fed the other diets. A DP/DE ratio of 16.4 g MJ?1 was sufficient to produce maximum growth for the large fish, while the DP/DE ratio of 18.8 g MJ?1 produced the highest growth in the small fish. In the large fish, the lowest FCR was obtained on a DP/DE ratio of 16.4 g MJ?1, while there was no clear difference in FCR within the small fish when diets of DP/DE ratios of 16.4–21.9 g MJ?1 were fed. The carcass-to-body ratio in the small fish decreased with decreasing DP/DE ratios. The fish fed the diet of 21.9 g MJ?1 had significantly lower fat and dry matter and higher protein content than fish of similar size fed the other diets. Increased dietary lipid content seemed to improve astaxanthin deposition in the small fish, while the large fish showed no significant differences in astaxanthin deposition due to dietary treatment. This study indicates that a DP/DE ratio of 14.1 g MJ?1 in high-energy diets for Atlantic salmon in sea water is below the optimal DP/DE ratio for growth and feed utilization, and that the optimal DP/DE ratio decreases with increasing fish weight. DP/DE ratios around 19 g MJ?1 for fish weighing 1 to 2.5 kg, and 16–17 g MJ?1 for fish weighing 2.5 to 5 kg, are suggested to be optimal. 相似文献
999.
1000.
The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single‐cell, protein‐based diet has a potential to promote gonad production of H. erythrogramma. 相似文献