响应面法优化大肠杆菌CD-2产偶氮还原酶培养基的条件

在摇瓶条件下,对大肠杆菌CD-2发酵生产过程中的主要培养基组成对产偶氮还原酶的影响进行了研究。根据响应面法,以单因子试验结果为基础,利用Plackett-Burma设计对影响E.coli CD-2产偶氮还原酶的相关因子进行了评估,并筛选出具有显著效应的3个因子:pH值、MgCl2、Na2HPO4。用最陡爬坡试验逼近以上3个因子的最大响应区域后,采用design expert 7.0统计软件的Box-Behnken设计以及响应面分析法,确定E.coli CD-2优化后的最佳培养基组成:甘露醇2 g.L-1、氯化铵3 g.L-1、接菌量5%、pH值为6.5、KH2PO42 g.L-1、Na2HPO46 g.L-1、MgCl20.99 g.L-1,优化后的酶活达到2.429 U.mL-1,是初始酶活的2.85倍。从而增强了E.coli CD-2所产的偶氮还原酶实际应用于污水处理的能力。     

Toxicarioside M, a new cytotoxic 10β-hydroxy-19-nor-cardenolide from Antiaris toxicaria

A new 10β-hydroxy-19-nor-cardenolide, named toxicarioside M (1), was isolated from the trunk bark of Antiaris toxicaria (Pers.) Lesch (Moraceae), along with six known cardenolides (convallatoxin (2), convallatoxol (3), convalloside (4), 3-O-ß-D-xylopyranosylstrophanthidin (5), glucostrophanthidin (6) and strophanthidin (7)). Their structures were elucidated on the basis of HR-MSⁿ analysis, spectroscopic methods (IR, UV, 1D and 2D NMR) and by comparison with data reported in the literature. The cardenolides were evaluated for their cytotoxic activity against KB, HCT-116, SF-268, MCF-7, HL-60, PC-3 and MRC-5 cell lines.     

Hypoglycemic effect of protopanaxadiol-type ginsenosides and compound K on Type 2 diabetes mice induced by high-fat diet combining with streptozotocin via suppression of hepatic gluconeogenesis

Compound K (CK) is a final intestinal metabolite of protopanaxadiol-type ginsenosides (PDG) from Panax ginseng. Although anti-diabetic activity of CK have been reported with genetic mouse models (db/db mice) in recent years, the therapeutic usefulness of CK and PDG in type 2 diabetes, a more prevalent form of diabetes, remains unclear. In the present investigation, we developed a mouse of non-insulin-dependent diabetes mellitus that closely simulated the metabolic abnormalities of the human disease. For this purpose, type 2 diabetes was induced in male ICR mice by combining of streptozotocin. The male ICR mice fed with HFD for 4 weeks received 100 mg/kg of STZ injected intraperitoneally. After 4 weeks, mice with fasting (12 h) blood glucose levels (FBG) above 7.8 mmol/L were divided into 3 groups (n = 12) and treated with vehicle (diabetes model, DM), 300 mg/kg/day of PDG and 30 mg/kg/day of CK for 4 weeks while continuing on the high-fat diet. Hypoglycemic effects of CK and PDG were consistently demonstrated by FBG levels, and insulin-sensitizing effects were seen during oral glucose tolerance testing (OGTT). Moreover, the mechanism of hypoglycemic effect in type 2 diabetic mice was examined. Gluconeogenic genes, Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase), were decreased in two treatment groups with CK showing greater effects. These findings demonstrated the hypoglycemic and insulin-sensitizing capabilities of CK on type 2 diabetes induced by HFD/STZ via down-regulation of PEPCK and G6Pase expression in liver.     

对穆棱林业局林地保护利用管理办法的讨论

通过走访调查,针对黑龙江省穆棱林业局林地保护利用提出了相关的管理办法和保护利用措施。     

动物疫病防控风险和对策措施

本文阐述了动物疫病的危害和动物防疫职责、任务、系统分析了动物疫病防范风险,提出了规范免疫和流通防疫监管、加快养殖方式转变、深化兽医体制改革、提升动物防疫设施、完善防控责任体系等工作举措。     

以营养呵护动物健康——访百奥明创始人、总裁ErIch Erber 先生和亚太区市场经理林素斌女士

百奥明公司1983年成立于奥地利,是一家专注于通过营养来促进动物健康的跨国公司。她开发和生产专业的饲料添加荆、预混料,并提供经济有效的服务来提高动物的健康和生长性能。通过最新的科技和广泛的研发项目,百奥明持续不断地提供高品质产品,包括霉菌毒素风险管理方案、天然植物性生长促进剂、饲料酸化剂及其它专业产品,来满足猪、家禽、奶牛和水产的日粮营养需要,并保证消费者健康和符合环保要求。     

四种植物纤维粉/聚丙烯复合材料应用性能

为了充分利用农作物及农业废弃物中的植物纤维,研究环境友好材料,研究了4种植物纤维粉/聚丙烯复合材料的拉伸强度、弯曲强度、弯曲弹性模量等力学性能,并对其吸水和热变形性能进行了分析。结果表明：麦秆粉与稻壳粉混合纤维粉填充聚丙烯时,复合材料有较好的性能;稻壳粉、混合纤维粉及松木粉分别填充聚丙烯复合材料的拉伸强度和弯曲强度相差不大;竹粉填充聚丙烯复合材料的力学性能较低,吸水性及加热后尺寸变化率较大,综合性能较差。稻壳粉与聚丙烯相容性较好,竹粉和松木粉与聚丙烯的相容性较差。稻壳粉、混合纤维粉能与聚丙烯制备性能较好的木塑复合材料。     

介质阻挡放电等离子体生物质的液化

为了探索常压快速生物质液化新方法,该文以木屑、秸秆、稻壳等常见生物质为研究对象,利用介质阻挡放电等离子体技术,在低温、常压条件下进行生物质液化的试验研究与分析。 研究结果表明：该方法具有反应速度快,反应条件温和、设备简单、产物性质稳定、低腐蚀性等一系列优点,是今后研究开发的方向之一。