棉籽粕在家禽生产中的应用研究进展

棉籽粕是一种产量高、营养丰富的非常规蛋白饲料资源,对解决我国蛋白饲料资源短缺问题具有重要意义。但棉籽粕中存在抗营养因子,长期饲喂会对家禽的生长、发育和繁殖造成不良影响,因此限制了其在家禽生产中的应用。因此,了解棉籽粕中抗营养因子的特性和脱毒方法,对棉籽粕在家禽生产中的高效利用具有重要意义。文章综述了棉籽粕的营养、抗营养因子的作用特点、棉籽粕常用的脱毒方法和常规棉籽粕和脱毒棉籽粕在家禽生产中的应用情况,为棉籽粕在家禽中的科学应用提供参考。

Brown planthopper E78 regulates moulting and ovarian development by interacting with E93

The brown planthopper(Nilaparvata lugens) is the main migratory pest in many rice growing areas in Asia. E78 is a member of the nuclear hormone receptor superfamily which plays an important role in egg development and maternal regulation of early embryogenesis. In this study, brown planthopper E78(NlE78) was cloned, and the predicted amino acid sequence showed that it contains two conserved domains: NR-LBD and DBD. qRT-PCR showed that the expression of NlE78 is high in the fifth instar nymphs and the ovaries of females. After downregulation of NlE78, the rate of moulting failure(33.2%) increased significantly, and ovarian development was delayed. However, when NlE78was downregulated together with NlE93, the emergence rate increased significantly(78.79%), and ovarian development was similar to that when NlE78 was downregulated but not delayed. A co-immunoprecipitation experiment showed that NlE78 interacts with NlE93, a crucial downstream transcription factor of the ecdysone signalling pathway. Cellular localization by immunofluorescence revealed that NlE78 and NlE93 are expressed in the nucleus. This study indicates that NlE78 regulates ovarian development and moulting, possibly through its interaction with NlE93. This study is of great significance for the development of new pesticides and control methods based on newly discovered targets.

基于计算机断层扫描技术重构三维生物扰动构造--以长江口现代沉积为例

生物扰动作用能够加速水层与底质的物质交换,对水层和底质的耦合作用有着重要的影响。受限于观测手段和观测方法,当前对于生物扰动构造的研究多停留在定性-半定量化的阶段。本文选取长江口现代沉积区的4个沉积物柱状样,利用计算机断层扫描技术对生物扰动构造进行三维重构,运用数字图像处理实现生物扰动强度的定量表征,对研究区域生物扰动构造发育的影响因素进行初步分析。结果表明:CT(computed tomography)值与沉积物粒级构成和含水率具有一定关系,能够较好地指示沉积物密度变化;该区出现挖掘构造、觅食虫孔构造、逃逸虫孔构造、生物遗迹构造等显性扰动构造类型,生物扰动强度介于0%-10%,扰动强度极大值出现在长江水下三角洲前三角洲和陆架过渡区,垂向上以及不同站位生物扰动构造差异显著;底质沉积物类型、上覆水团性质以及沉积速率是影响该区生物扰动构造发育的主要因素。

南黄海底栖有孔虫组合对1855年黄河改道的响应

黄河改道是中国东部陆架沉积物源汇过程的特有现象,对包括南黄海在内的东部海域的沉积环境具有重要的影响。本研究通过南黄海YSL04柱的底栖有孔虫的分析,结合岩心粒度数据和放射性核素210Pb的年代标定,揭示了1855年黄河改道事件在南黄海中部泥质区西南边缘的沉积记录,探讨了有孔虫对黄河改道事件的响应。研究表明:改道之前,研究区形成了相对细颗粒沉积,有孔虫的丰度、分异度均较低,以广盐的近岸浅水冷水属种为主,研究区受河流作用和黄河入海淡水的影响,水体盐度较低;改道之后,废黄河三角洲发生快速侵蚀,岸线后退,沉积颗粒变粗,有孔虫丰度、分异度均相对较高,有孔虫组合中喜冷、窄盐的陆架浅水种含量增加,研究区波浪作用增强,失去黄河淡水注入,但是受黄海沿岸流的影响,表现为研究区水体盐度升高而水体温度降低。该研究显示1855年黄河北归渤海对南黄海沉积环境具有显著的影响。