Effects of dietary protein levels on the growth,survival, amylase and trypsin activities in large yellow croaker,Pseudosciaena Crocea R., larvae

A feeding trial was conducted to investigate the effects of dietary graded protein levels on the growth, survival, amylase and trypsin activities of large yellow croaker (Pseudosciaena crocea R.) larvae from 12 to 42 days after hatching (DAH). Five approximately isoenergetic microbound diets (16.65 MJ/kg diet) were formulated to contain different protein (47.1%, 52.0%, 57.1%, 62.2% and 67.5%) levels. Frozen copepods, containing 54.5% crude protein (CP), 6.0% crude lipid, 27.2% ash and 6.7% glycogen, were used as a control. Each diet was randomly fed to triplicate groups of larvae with an initial mean body weight of 1.76 ± 0.09 mg (mean ± SD) in 180 L white plastic tanks, and each tank was stocked initially with 3500 larvae. Both the survival and the specific growth rate (SGR) of large yellow croaker larvae significantly increased with increasing dietary protein level up to 57.1%, and decreased thereafter. Frozen copepods resulted in intermediate survival and low SGR compared with the other diets. Whole‐body moisture and protein of larvae were not significantly affected by the dietary protein level. In contrast, whole‐body lipid of larvae fed diet with 47.1% CP was significantly higher (P<0.05) than those from fish fed the diets containing more than 57.1% CP. Additionally, fish fed the frozen copepods had the lowest whole‐body protein and lipid. The amylase‐specific activity increased with increasing dietary carbohydrate level during the period of this experiment. However, trypsin activity was not significantly affected by the dietary protein content before 42 DAH, indicating a later onset of trypsin than amylase in the regulation of enzymatic synthesis induced by a dietary substrate.     

鲤鱼肠道细菌及其淀粉酶对宿主消化的影响

本文就鲤鱼肠道细菌对其宿主的影响和细菌淀粉酶对宿主消化的影响作了探讨。从鲤鱼肠道筛选细菌菌株６３株，这上结细菌中淀粉酶产生菌分布较广，溶血毒素产生菌较少，且产毒素的６株菌无致病性。淀粉酶活力较高的ＣＣＩ１３９菌株的淀粉酶和鲤鱼肝胰淀粉酶的最适ｐＨ和反应产物都不相同。原位酶反应法显示鲤鱼肠道食物混合液及肠壁样品中均有细菌淀粉酶。本文结果证明了鲤鱼肠道不稳定的细菌群落，细菌淀粉酶对鲤鱼消化食物的淀粉起     

Tissue-specific distribution of amylase in the mosquitofish (Gambusia affinis holbrooki)

Tissue-specific expression of alpha-amylase (E.C.3.2.1; α 1,4-glucan-4-glucano-hydrolase) was studied in the mosquitofish (Gambusia affinis holbrooki). Gut activity patterns, immunohistochemical distribution in the hepatopancreas and tissue-specific activities and amount of amylase protein were characterized. In the gut, activity was observed all along the gut and no variation in this pattern was observed in individuals from two natural populations. In the hepatopancreas, amylase is found in pancreatic tissue. Highest amylase activity was observed in gut tissue but highest amount of amylase protein was found in the hepatopancreas. Paper III in the series on the amylase gene-enzyme system in fishes.     

四种金属离子对地图幼鱼淀粉酶活性的影响

以酶学分析的方法研究了4种金属离子Na＋、K＋、Ca2＋、Mg2＋分别在单因子和双因子条件下对地图幼鱼淀粉酶活性的影响。结果表明：在设定的浓度梯度内,单因子条件下,除Ca2＋对淀粉酶活性起强烈的抑制作用外,其余3种离子对淀粉酶活性均起促进作用,其中Mg2＋的促进作用最强。双因子条件下,Na＋和K＋互作对淀粉酶的激活作用高于2者单独作用,Na＋和Mg2＋在一定浓度下互作对淀粉酶的激活作用高于2者单独作用,而K＋和Mg2＋互作则会抑制Mg2＋的激活作用。     

北极海冰低温微生物的生长条件及其胞外水解酶的研究

对北极海冰获得的14株低温微生物进行培养条件和胞外水解酶活力的研究,结果表明:(1)菌株最适生长温度均为15℃和20℃左右,最适pH在8.0左右,在酸性条件下几乎不生长。生长需要一定浓度的盐,在3%NaC l的培养基中能很好的生长,而在没有NaC l的培养基中不生长。(2)14株菌株能不同程度的分泌胞外水解酶。(3)菌株i429,i539在低温下产纤维素酶的活力最高,具有低温酶的特性。     

宋河酒曲中产淀粉酶芽孢菌的分离鉴定及产酶特性

为了有效控制宋河酒曲的制曲过程和发酵进程,对宋河酒曲中产淀粉酶芽孢菌进行了分离鉴定并研究筛选菌株的产淀粉酶特性。结果表明:从宋河酒曲中共分离到12株产淀粉酶芽孢菌,均属革兰氏阳性杆状菌,初步鉴定归为1个属5个种,即芽孢杆菌属(Bacillus)、坚硬芽孢杆菌(Bacillus firmus)、枯草芽孢杆菌(Bacillus subtilis)、地衣芽孢杆菌(Bacillus licheniformis)、凝结芽孢杆菌(Bacillus coagulans)、巨大芽孢杆菌(Bacillus megaterium),其中,坚硬芽孢杆菌是宋河大曲产淀粉酶芽孢菌的数量优势菌群,获得1株地衣芽孢杆菌SQ2为中温型高产淀粉酶菌株,其液态发酵产酶特性为37℃培养,前24h产酶较弱,此后,酶活力迅速上升,72h达到最大值为89μg/(mL.min),产酶旺盛期发生在菌体成熟期和衰亡初期,产酶过程pH值先稍偏酸性后接近中性。     

杂交水稻与稗草种间竞争的优势表现 Ⅰ.水稻与稗草混播栽培的生理生态特性(英文)

试验结果表明，与常规稻相比，稗草具有一般杂草的生长特性，即具有前期生长优势、后期生长劣势之特性。这与稗草从种子萌发至三叶期前的异养阶段，植株体内α 淀粉酶活性强和自养阶段初期叶片净同化率高有关。但杂交稻在种子萌发期间（３１２ｄ）和大田自养阶段叶片净同化率均显著高于常规稻和稗草，具有较强的种间竞争优势，特别是在水稻与稗草生长初期，这种种间竞争优势更加明显，表明杂交稻的产量优势也与其它作物—杂草生态系统中保持较强的竞争优势有关。     

Evaluation of serum iso-amylase in the normal dog using an improved electrophoretic technique

Six iso-amylase fractions are known to exist in human serum, three originating from the salivary glands and three from the pancreas. Although it is known that a different number and source of iso-amylase fractions occur in the dog, the routine detection of all the canine iso-amylase fractions has not been previously established. Earlier methods detected either two iso-amylase fractions or, in a proportion of cases, four fractions. A method is described which detects four iso-amylase fractions in 95% of normal canine serum samples. Trials have shown the method is reproducible and that freezing at -40°C has no effect on iso-amylase activity. The normal values for iso-amylase are recorded in 18 normal dogs.     

膨化与加酶玉米对断奶仔猪血液指标及胰腺和肠道淀粉酶活性的影响

选择96头断奶仔猪，随机分为4组，每组6个重复，每个重复4头仔猪，分别饲喂普通玉米、膨化玉米、普通玉米加酶及膨化玉米加酶为主要能量原料的饲料，研究了膨化与加酶玉米对断奶仔猪血液指标以及胰腺组织和小肠内容物淀粉酶活性的影响。结果表明，膨化和加酶处理玉米以及二者互作对断奶仔猪血清葡萄糖和尿素氮浓度均无显著影响。膨化和加酶处理均可显著提高仔猪断奶14d时十二指肠和空肠内容物的淀粉酶活力。对断奶28d时胰腺和小肠各段内容物淀粉酶活性均无影响；在整个试验期，未见到膨化和加酶处理的互作。     

Binding of lipase, amylase and protease to intestinal epithelium as affected by carbohydrates and lectins in vitro

Intraluminal digestive enzymes were shown to bind to chick intestinal epithelial surface (glycocalyx). Affinity of the intestinal epithelium for the enzymes decreased in the order, lipase > amylase > protease. The plant hemagglutinins, Con A, phytohemagglutinin, pokeweed mitogen and raw soybean effectively released lipase and amylase from the glycocalyx. Based on specific inhibition of binding by sugars, such as fucose and N-acetylated sugars, lipase and amylase appeared to be bound to blood group antigen-like sugar moieties on the glycocalyx of the microvilli.