多糖、寡糖、蛋白酶对凡纳滨对虾生长、消化酶活性及血清非特异性免疫的影响

在基础饲料(对照组)中分别添加0.2%β-葡聚糖、0.05%黄芪多糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT,饲喂初始体重为(4.55±0.08)g的凡纳滨对虾(Litopnnaus vannamei)6周,考察对凡纳滨对虾生长性能、血清非特异性免疫及消化酶活性的影响。结果表明:与对照组相比,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖及175 mg/kg蛋白酶PT可分别提高凡纳滨对虾增重率16.19%、12.78%、11.25%(P<0.05),降低饲料系数0.10、0.09、0.09(P<0.05);各处理组在肌肉水分、灰分、粗脂肪和粗蛋白含量上无显著差异(P>0.05);在血清非特异性免疫方面,各多糖、寡糖和蛋白酶添加组均显著提高血清酚氧化酶活力(P<0.05),添加0.4%甘露寡糖可提高溶菌酶、碱性磷酸酶活力(P<0.05),添加0.2%β-葡聚糖、0.4%甘露寡糖可显著提高超氧化物歧化酶活力(P<0.05);在消化酶活性方面,添加175 mg/kg蛋白酶PT可显著提高肝胰脏蛋白酶、脂肪酶和肠蛋白酶活性(P<0.05),添加0.2%β-葡聚糖及0.4%甘露寡糖可显著提高胃蛋白酶和肝胰脏脂肪酶活性(P<0.05)。上述结果表明,饲料中添加0.2%β-葡聚糖、0.4%甘露寡糖、175 mg/kg蛋白酶PT可提高凡纳滨对虾生长性能、改善消化酶活性,葡聚糖和甘露寡糖还具有改善血清非特异性免疫的功能,而添加0.05%黄芪多糖对凡纳滨对虾增重率、血清非特异性免疫无显著影响。     

烘烤变黄环境对上部叶蛋白酶活性的影响

运用二因素最优回归设计,研究烤烟品种K326烘烤变黄期温度和相对湿度对上部叶蛋白酶活性的影响。结果表明,在烤烟上部叶烘烤变黄过程中蛋白酶活性均呈先升后降的变化趋势,在变黄温度和相对湿度范围内低温和中湿有利于维持上部叶蛋白酶活性在较高水平。从提高上部叶蛋白酶活性的角度考虑,上部叶烘烤的变黄恒定温度为34.0℃左右、相对湿度88.0%(即干湿差1.5℃)左右为宜。     

土壤中产碱性蛋白酶菌株的筛选及产酶条件的研究

[目的]从土壤中筛选产碱性蛋白酶菌株,并优化产酶条件。[方法]采用平板分离方法从土壤样品中分离出8株产碱性蛋白酶菌株,采用滤纸片法和Folin-酚法测定8个菌株的产酶能力。将具有较强产酶能力的菌株作为目的菌株,研究该菌株产酶能力的影响因素,并采用正交试验法优化产酶条件。[结果]经过初筛和复筛,从土壤中得到一个碱性蛋白酶高产菌株（5号）,作为目的菌株,其产酶能力为6.00 U/ml,为地衣芽孢杆菌的134.1%,该菌株为革兰氏阳性芽孢梭菌。正交试验表明,在pH为11的初始发酵培养基中添加0.3%蔗糖和0.8%蛋白胨,并以105个/ml的接种量接种,目的菌株可得到较好的产酶效果,且蛋白胨对该菌株产酶能力具有显著影响。[结论]该研究为产碱性蛋白酶菌株的筛选提供了理论参考。     

不同温度对两种泥鳅消化道蛋白水解酶活性的影响

研究了不同温度对泥鳅(Misgurnus anguillicaudatus)和大鳞副泥鳅(Paramisgumusa dabryanus)胃、肠蛋白水解酶活性的影响.结果表明,温度会影响泥鳅、大鳞副泥鳅小肠和胃蛋白水解酶活性.在DH值7.5时,泥鳅及大鳞副泥鳅的胃最适温度都为45℃,蛋白水解酶活性分别为1 005.23、975.6μg·min-1;泥鳅的肠最适温度为40℃,其酶活性为48.7μg·min-1,大鳞副泥鳅的肠最适温度为45℃.其酶活性为78.23μg·min-1.     

饲粮硒对种公鸡睾丸中硒含量和硒蛋白酶基因mRNA表达的影响

本试验旨在研究饲粮硒对海兰褐种公鸡睾丸中硒含量和硒蛋白酶基因mRNA表达的影响.选取224只48周龄海兰褐种公鸡,随机分为7个处理,每个处理4个重复,每个重复8只.将亚硒酸钠(SS)和酵母硒(SY)2种硒源分别以3个硒水平(0.2、0.5和0.8 mg/kg)添加到海兰褐种公鸡基础饲粮中,对照组饲喂基础饲粮,进行为期3...     

栉孔扇贝蛋白酶和淀粉酶活力的初步研究

研究了栉孔扇贝两种主要消化酶－－蛋白酶和淀粉酶与温度和ｐｈ值的关系，结果表明，在４．８℃与７５℃之间蛋白酶的最适温度为６０℃，在５℃与６０℃之间淀粉酶的最适温度为２５℃，蛋白酶的最适ｐＨ值有两个，分别是２．６１和７．７７，淀粉酶的最适ｐＨ值为６．５。栉孔扇贝蛋白酶和淀粉酶的活性与酶本身的性质及栉孔扇贝的生理状态有关。     

A biochemical and immunological comparative study on Trypanosoma equiperdum and Trypanosoma evansi

Trypanosoma equiperdum and Trypanosoma evansi were purified by three or four cycles of low-speed centrifugation and final filtration through DEAE cellulose. The purified trypanosomes were used in comparative biochemical and immunological studies. Comparative polypeptide pattern analysis revealed that T. equiperdum showed 21 polypeptide bands, whose M _r ranged from >200 to 14.8 kDa. T. evansi showed 25 polypeptide bands in the M _r range 97–14.8 kDa. The main differences were associated with the presence of secondary bands, relative intensity and the number of bands. Both species gave seven glycoprotein bands; those of 97 and 68 kDa were present in T. equiperdum but absent in T. evansi. Bands of 61 and 28 kDa were present in T. evansi but not in T. equiperdum. Anti-T. equiperdum sera recognized four homologous antigens and cross-reacted with three antigens of T. evansi. Anti-T. evansi sera recognized three homologous antigens and cross-reacted with four T. equiperdum antigens. Four identical proteolytic protease bands were present for both species, while only one surface protein was detected for each species: 66 kDa for T. equiperdum and 62 kDa for T. evansi.     

耐低温兼性厌氧蛋白酶产生菌192的筛选、鉴定及酶学性质

为了提高厌氧水解效率,采用双层平板法筛选出一株耐低温兼性厌氧蛋白酶产生菌192.经形态、生理生化和16S rDNA序列分析鉴定为蜡状芽孢杆菌(Bacillus cereus),对其产酶条件进行了初步研究.结果表明,该茵的最适生长温度为30℃,生长8～12h达对数期,初始pH 7.5时酶活力最高.蛋白酶最适反应温度为45℃、pH 7.0,酶活力最高达39.3 U/mL.该酶在50℃以下,pH 6.0～9.0性能稳定.在60℃以上热稳定性很差,70℃保存lh酶活力全部丧失.     

Study on Protease Properties of Bacillus subtilis JNB001

This experiment was aimed to study the protease properties produced by Bacillus subtilis JNB001 via the index of protease activity to investigate the effects of pH,temperature and other factors on the enzymatic reaction,and the ability of the crude enzyme solution to hydrolyze various animal protein was measured by the degree of hydrolysis.The results showed that the most suitable pH of reaction was 8.0 and the temperature was 45 ℃.The crude enzyme solution in the range of pH 5.5 to 9.0 was relatively stable,while it was not suitable for the preservation of the enzyme solution when pH was over 9.0.At 45 ℃ it had good thermal stability when exceed 50 ℃ for 10 min, the residual activity had been less than 60%.Metal ions such as Ca²⁺ and Mg²⁺,reducing agent like DTT,surfactant as Tween-80,etc.could greatly improve the enzyme activity.On the opposite,Fe²⁺ and Cu²⁺ as well as other ions,metal chelator EDTA,denaturant SDS and other materials could inhibit the protease activity.The K_m was 6.43 mg/mL,and V_max was 47.39 μg/min.It had a range of reaction pH from 7.0 to 9.0 and temperature from 40 to 50 ℃ in the situation for different protein substrates.The crude enzyme solution could hydrolyze pig hair,pig nail,hair removal of cowhide,gelatin and other hard protein substances.The results provided the strong date support for the Bacillus subtilis JNB001 which could be used in dead livestock harmless biological treatment system and other aspects of industrial applications.     

菜籽饼粕对土壤有机质和土壤酶活性的影响

通过在室内培养条件下研究菜籽饼粕对土壤有机质和土壤酶活性的影响,结果表明,将菜籽饼粕加入第四纪黄壤和中性紫色土之后,土壤有机质含量先增后降;土壤酶活性的变化因酶的种类而异：蛋白酶和脲酶活性在初始期显著提高,之后降低;过氧化氢酶同样在短时间内提高,然后保持恒定状态;而蔗糖酶活性则随着菜籽饼粕的加入受到了抑制,一直呈下降趋势,这可能与菜籽饼粕的用量和抗营养成分有关。