一株中华绒螯蟹病菌鉴定及其致病机理的研究

确定了一株蟹源致病菌(HX-1)为恶臭假单胞菌Pseudomonasputida。该菌对小鼠和河蟹致死率分别为100%(8/8)和87.5%(7/8)。对小鼠的半数致死量LD50为2.9×107/只。同时,该菌还具有凝集鸡、小鼠、牛、鲫、鲢、兔、家鸽的红细胞和粘附Hela细胞的能力。此外,在25℃培养条件下细菌产生的胞外产物(ECP)具有溶血性,但无酪蛋白酶活性;对河蟹有致病性,致死率为60%。

不同饲料对接种东方蜜蜂微孢子虫意蜂工蜂的影响

为探讨不同饲料对微孢子虫感染工蜂的影响,给每只意蜂工蜂接种4400个东方蜜蜂微孢子虫孢子,再分别饲喂50%蔗糖浆(W/V)、含5%蛋清的50%蔗糖浆(W/V),及花粉与50%蔗糖浆等重混合物(1:1)。在30℃,70%±15%RH的黑暗环境中饲养12天后,结果显示:饲喂三种饲料的接种工蜂存活率和微孢子虫感染率之间无显著差异(P>0.05);饲喂蛋清糖浆和花粉糖浆的两组工蜂,严重感染的工蜂比例、中肠蛋白浓度、酪蛋白酶活性,均极显著高于饲喂糖浆组(P<0.01),且中肠蛋白浓度与酪蛋白酶活性之间成正相关关系。

A Novel Exponential Kinetic Model for Casein Tryptic Hydrolysis to Prepare Active Peptides

The kinetics of casein tryptic hydrolysis to prepare activepeptides was investigated. Taking into account the reaction mechanismincluding single substrate hydrolysis, irreversible enzymeinactivation, and substrate inhibition, a set of exponentialequations was established to characterize the enzymatic hydrolysiscurves. The verification was carried out by a series of experimentalresults and indicated that the average regressive error was less than5/100. According to the proposed kinetic model, the kinetic constantsand thermodynamic constants of the reaction system were alsocalculated.