长薄鳅幼鱼消化道指数和消化酶活性研究

测定了长薄鳅(Leptobotia elongate Bleeker)幼鱼(8.0～110.1g)的消化道指数和不同体重组(10 g、30 g、50g)幼鱼的胃、肝胰脏、前肠、中肠、后肠的淀粉酶、胃蛋白酶、胰蛋白酶及脂肪酶活性.结果:(1)长薄鳅幼鱼肝指数平均为(1.400±0.004)％,比肠长平均为(0.418±0.080),体重与体长呈幂函数相关,相关式为:W=0.019L2.8181(R2=0.948,P＜0.01,n=43);鱼体肥满度在30 g组中最高.(2)各部位消化酶活性均以蛋白酶＞脂肪酶＞淀粉酶;各体重组淀粉酶活性在肝胰脏中最高(P＜0.05);蛋白酶活性在胃和中肠中较高;脂肪酶活性沿消化道从前至后升高;(3)各部位淀粉酶活性在各体重组间变化不大,胃蛋白酶、肠段胰蛋白酶和脂肪酶活性随体重增加而下降.本研究认为长薄鳅幼鱼为杂食、偏肉食性,其消化酶活性存在组织特异性,体重30 g左右是其营养需求转变或者生长发育的重要时期.     

枯草杆菌的淀粉酶基因在大肠杆菌中的表达

根据枯草杆菌(Bacillus subtilis)基因文库中的淀粉酶基因的碱基序列,设计引物。以枯草杆菌菌体DNA为模板,利用PCR扩增出分子量大约为2.3 kb的淀粉酶基因片段。借助于核酸内切酶和连接酶把该基因植入到pHMSXD1质粒中,构建pHMSXD2质粒载体。通过高压电击处理把载体植入到大肠杆菌(JM10)中并成功表达。该株大肠杆菌在酶基因表达后,其淀粉酶活力达到1.037 6 U/mL(LB培养液)和1.361 0 U/mL(矿物元素培养液),分别比原始的枯草杆菌的淀粉酶活力提高了46倍和286倍。     

Influence of extreme K:Na ratios and high substrate salinity on plant metabolism of crops differing in salt tolerance

K⁺/Na⁺ and Cl^‐ effects on activity of amylases as well as on their isoenzyme pattern in leaves of bushbeans and sugarbeets at the beginning of salinity stress were investigated, in plants grown in water culture under controlled environmental conditions. Alpha‐ and beta‐amylase activity in beans increased, particularly due to K⁺ and Cl^‐ supplied. In sugarbeets amylase activity remained unchanged as a result of K/Na treatment in combination with Cl and decreased using SO₄ ^2‐ as counterion. A direct correlation of amylase activity to the starch content of both species was not detctable. Particularly α‐but also ß‐amylase was most strongly inhibited by KCl “in vitro”. Independent on their origin, amylases from bushbeans and sugarbeets did not show any differences in ionic inhibition “in vitro”. The isoenzyme pattern of the species was different, but no clear ionic effect was detectable. Amylolytic activity is evidently not a causative factor for restricted starch mobilization in leaves under an early salinity stress. It is suggested that amylases are indirectly involved in starch formation via degradation due to a lack of a carbohydrate sink under salinity stress. Differences in salt tolerance of the investigated crops are obviously not related to different “in vitro” properties of amylases.     

南昌白猪血清转铁蛋白血液结合素及淀粉酶的遗传多态性研究

应用改进的淀粉凝胶电泳法研究了培育品种南昌白猪进贤系、南昌系、安义系及其杂交亲本品种星子黑猪、大约克猪的转铁蛋白（Ｔｆ）、血液结合素（Ｈｐｘ）和淀粉酶（Ａｍ）３种血清蛋白的多态性,测定并分析了各自的基因型及基因频率的特点,结果表明：南昌白猪３个系的遗传结构与大约克猪甚为相似,而与星子黑猪的差异明显。     

萝卜淀粉酶活性的配合力分析及遗传参数的估计

以大青皮萝卜(P1)、青萝卜(P2)、灯笼红(P3)、满堂红(P4)和浙大长(P5)为杂交亲本,按5×5完全双列交配设计,对萝卜淀粉酶活性进行了配合力分析和遗传参数的估算。结果表明:亲本P3和P5的淀粉酶总活性一般配合力较高,分别为9.243和0.829,为优良亲本可直接利用;杂交组合P2×P4、P5×P3、P1×P2和P4×P5的总酶活性特殊配合力较高,分别为11.983,7.250,3.983和1.343,有增加淀粉酶活性的潜力。α-淀粉酶活性、β-淀粉酶活性和总酶活性狭义遗传力分别为23.85%、44.27%和38.47%,β-淀粉酶活性和总酶活性遗传力较高,可在早代开始选择;而α-淀粉酶活性遗传力较低,受周围环境影响大,可于晚期世代选择。     

丹皮,泽泻混和物对黄粉虫幼虫生长发育和体内淀粉酶的影响

就中药材丹皮、泽泻及其混和物饲料对黄粉虫幼虫生长发育影响和体内淀粉酶活性进行了研究,结果发现;（１）丹皮处理组幼虫的日均增长量为负值,与其余各处理组的差异达到了显著性水平;（２）混和物处理组幼虫本内淀粉酶活性与庆皮处理组、泽泻处理组和面粉处理组比较,存在不同程度的差异,说明丹皮物质对黄粉虫幼虫生长发育秀明显抑制作用;丹皮、泽泻两种中药材均对黄粉虫幼虫体内的淀粉酶活性有影响,从一个侧面反映了中药材对     

稻米品质与淀粉酶和蛋白组分的关系研究进展

水稻品质改良已成为当前育种工作的主要趋势,优质米品种选育和米质研究是当前及今后水稻育种的重点。综述了水稻种子α,β-淀粉酶活性的差异与稻米品质之间的关系,以及种子蛋白组分间的差异与稻米米质的相关性。探讨了水稻品种间品质差异与α,β-淀粉酶活性和蛋白组分的关系,并对其在育种中的意义及应用进行了展望。     

植酸和氯离子对稻米品质的影响

 以原丰早为材料进行了在不同时期施用植酸与氯离子的试验。在水稻抽穗至成熟期间叶面喷施植酸，能抑制水解酶类的活性，减弱淀粉酶分解淀粉的反应，提高淀粉合成酶的活性，有利于淀粉合成，改善稻米品质。水稻齐穗期叶面喷施50、100 mg/kg 两种浓度的植酸，碎米率的平均值比对照低2. 8～23. 1个百分点，整精米率上升5～7个百分点；垩白等级、垩白率降低，乳白米粒减少，与对照相比差异显著；对碱消值、直链淀粉含量亦有影响。氯离子作为淀粉酶的激活剂，喷施后能抑制淀粉合成酶的活性，对稻米品质呈逆向效应。     

Studies on amylase inhibitors in some Egyptian legume seeds

Amylase inhibitor activity was determined in four legume seeds which are widely consumed in Egypt. The effect of dehulling, heat treatment, soaking and germination were also assessed. The results showed that faba bean contained the highest activity of amylase inhibitor followed by cowpea, lentils, then chickpea. Dehulling resulted in raising the amylase inhibitor activities in all samples investigated, while heat treatment and cooking lowered it. Soaking for 10 h and germination eliminated completely the inhibitor from all samples.