The morphological and physiological characteristics of Bacillus thuringiensis strains were analyzed and conditions for obtaining culture fluid with maximum yield of secreted RNases were determined. Zymographic analysis showed that culture fluid of B. thuringiensis strains along with low-molecular-weight (15-20 kDa) RNases contained enzymes with a molecular weight ~55 kDa and their content depended on the duration and conditions of culturing. Preparations based on B. thuringiensis culture fluid were effective against human influenza virus A/Aichi/2/68 (H3N2). In experiments on mice infected with 10 LD50 influenza virus strain A/Aichi/2/68 (H3N2), we selected effective variants of preparations based on culture fluid of B. thuringiensi strains for preventive administration that provided reliable protection of infected animals (protection coefficient 50%), close to that of the reference drug Tamiflu.

中文翻译：

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细菌菌株苏云金芽孢杆菌代谢物在体外和体内对人流感病毒 A/Aichi/2/68 (H3N2) 的有效性评价

分析了苏云金芽孢杆菌菌株的形态学和生理学特征，并确定了获得具有最大分泌 RNase 产量的培养液的条件。酶谱分析表明，苏云金芽孢杆菌菌株的培养液和低分子量 (15-20 kDa) RNase 含有分子量 ~55 kDa 的酶，其含量取决于培养的持续时间和条件。基于苏云金芽孢杆菌培养液的制剂对人流感病毒 A/Aichi/2/68 (H3N2) 有效。在对感染 10 LD50 流感病毒 A/Aichi/2/68 (H3N2) 的小鼠进行的实验中，我们选择了基于 B.