原代培养大鼠松果体细胞的增殖与分化——免疫组织化学研究

目的：探讨体外培养大鼠松果体细胞的生长、增殖及分化。方法：采用MTT测定法BrdU及5－HT免疫组织化学方法。结果：相差显微镜观察可见培养的松果体细胞呈小圆形或不规则形,初期聚集成巢,以后逐渐散贴壁,有强折光性,细胞体随培养时间的延长而增大,MTT检测证实。培养的松果林体细胞增生较活跃,细胞倍增时间在培养第9天,第11天左右高峰。BrdU免疫组化法对松果体细胞分裂与增殖的观察及统计结果与MTT检验结果相符。5－HT阳性细胞占培养细胞总数的80％以上,结论：体外培养能获得生长增殖旺盛,具有一定生理功能的松果体细胞。     

海洋生态资本概念与属性界定

海洋生态资源是人类社会经济发展的基础,对其进行资本化界定是对其进行价值评估和资本化管理的前提。基于自然资本和生态系统服务两大理论,结合国内外学者对"自然资本"、"生态资本"等概念的界定和认识,考虑海洋生态系统的特性,提出了海洋生态资本的概念,认为海洋生态资本是能够直接或间接作用于人类社会经济生产、提供有用的产品流或服务流的海洋生态资源。海洋生态资本的价值是指海洋生态资本的存量价值及其产生的收益流价值,包括各类海洋生态资源的现存量价值及其组成海洋生态系统整体而产生的生态系统服务价值。比较了海洋生态资本与海洋生态系统服务、生态资产、自然资本、海洋资源等概念的异同,进而探讨了海洋生态资本的一般属性及其特殊属性。     

Expression of human aspartyl beta-hydroxylase and preparation of its monoclonal antibody

We investigated the mechanism of human aspartyl beta-hydroxylase (HAAH) in early diagnosis of tumors. The encoding gene of HAAH was cloned from the hepatic carcinoma by RT-PCR and expressed as a fused protein in the prokaryotic vector pBV-IL1. The expressed HAAH was purified by Ni(2+)-NTA purification column and the purified protein was then used to immunize Balb/c mice. Three hybridoma cell lines (respectively designated H3/E10, E4/F12 and G4/D8) stably expressing the monoclonal antibody specific to HAAH fusion protein were obtained. The specificity and sensitivity of the monoclonal antibody were assessed by indirect enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Finally, the monoclonal antibody expressed by H3/E10 cell line was used to detect the expression of HAAH in several tumor cell lines by indirect immuno-fluorescence, and the specific fluorescence was observed. In conclusion, this study successfully constructed the recombinant prokaryotic vector pBV-IL1-HAAH and prepared HAAH-specific monoclonal antibody for further study of the structure and function of the protein. The result may also lay solid foundation for the research of the molecular mechanism of HAAH in early diagnosis of tumors.     

Vesicle-associated membrane protein-8/endobrevin negatively regulates phagocytosis of bacteria in dendritic cells

Phagocytosis is a specialized mechanism used by mammalian cells, particularly the cells of the immune system, such as dendritic cells (DC) and macrophages, to protect the host against infection. The process involves a complex cascade of pathways, from the ligation of surface receptors of phagocytes with components of the microorganism's surface, formation of phagosomes and subsequently phagolysosomes, to the eventual presentation of foreign Ags. Vesicle-associated membrane protein (VAMP)-8/endobrevin has been shown previously to function in the endocytic pathways. Our results showed that VAMP-8 colocalized with lysosome-associated membrane protein-2, and a significant amount of VAMP-8 was recruited to the phagosomes during bacterial ingestion. However, overexpression of VAMP-8 significantly inhibited phagocytosis in DC. We also found that the phagocytic activity of VAMP-8-/- DC was significantly higher than wild-type VAMP-8+/+ DC, thus further confirming that VAMP-8 negatively regulates phagocytosis in immature DC.     

A Space-For-Time (SFT) Substitution Approach to Studying Historical Phenological Changes in Urban Environment

Plant phenological records are crucial for predicting plant responses to global warming. However, many historical records are either short or replete with data gaps, which pose limitations and may lead to erroneous conclusions about the direction and magnitude of change. In addition to uninterrupted monitoring, missing observations may be substituted via modeling, experimentation, or gradient analysis. Here we have developed a space-for-time (SFT) substitution method that uses spatial phenology and temperature data to fill gaps in historical records. To do this, we combined historical data for several tree species from a single location with spatial data for the same species and used linear regression and Analysis of Covariance (ANCOVA) to build complementary spring phenology models and assess improvements achieved by the approach. SFT substitution allowed increasing the sample size and developing more robust phenology models for some of the species studied. Testing models with reduced historical data size revealed thresholds at which SFT improved historical trend estimation. We conclude that under certain circumstances both the robustness of models and accuracy of phenological trends can be enhanced although some limitations and assumptions still need to be resolved. There is considerable potential for exploring SFT analyses in phenology studies, especially those conducted in urban environments and those dealing with non-linearities in phenology modeling.     

物理环境影响蛋白质晶体形核的研究进展

物理环境是影响蛋白质晶体形核的重要因素。文中回顾了各种物理环境如光、电场、超声波、磁场、微重力、温度、机械振动、异相形核界面对蛋白质晶体形核的影响,并对各物理环境下蛋白质晶体形核的可能机制进行探讨,展望了利用物理环境影响蛋白质晶体形核的研究前景。     

预测蛋白质可结晶性研究进展

解析蛋白质的三维结构具有重要的生物学意义,更是蛋白质功能研究和理性药物设计的基础。目前解析蛋白质结构最重要的方法是X-射线衍射晶体学解析技术。但是运用该技术解析蛋白质结构的关键是获得高质量的蛋白质晶体。然而,据统计仅有42%的可溶纯化蛋白质能够得到晶体,即不同蛋白质的可结晶性表现不同。由于实验方法验证蛋白质的可结晶性耗时耗力,因此,有研究者运用计算机模拟的方法预测蛋白质的可结晶性,从而节省资源与成本并且提高实验的成功率。本文结合我们的研究工作,介绍了几种目前较为成功的蛋白质可结晶性预测方法及其研究途径。     

不同C/N对生物絮凝硝化作用强度及微生物群落的影响

为了探究不同C/N(投入的总碳质量/投入的总氮质量)对生物絮凝硝化作用强度及微生物群落的影响,设置C/N为10∶、15∶1、20∶1、25∶1、30∶1进行相关研究.结果发现:C/N为10∶1和15∶1两组NO3-的积累量显著高于其他组的(P＜0.05),且C/N为10∶1和15∶1两组NO3-的积累量存在显著性差异(P＜0.05).5个处理组的氧化还原电位(ORP)在实验第一天迅速下降到负值,但5组间ORP变化均无显著性差异(P＞0.05).从节约碳源的角度考虑,在第一批次实验筛选出的差异组间,即在C/N为10∶1和C/N为15∶1之间,设置C/N为10∶1、11∶1、12∶1、13∶1和14∶1,对照组不添加葡萄糖.结果显示,随着C/N的升高,各处理组NO3-的积累量逐渐下降.不添加碳源组NO3-的积累量明显高于其他组的(P＞0.05).不添加碳源糖组与C/N为10∶1、11∶1组NO3-的积累量存在显著性差异(P＜0.05),C/N为10∶1和15∶1组与C/N为12∶1、13∶1和14∶1组NO3-的积累量存在显著性差异(P＜0.05).6个处理组ORP在实验第一天都迅速下降到负值,但6组间ORP变化均无显著性差异(P＞0.05).将NO3-积累量有显著差异性的3个处理组(不添加碳源组,C/N=10、12组)进行高通量测序,发现3个处理组第一优势菌门和第一优势菌纲均为放线菌门和放线菌纲.在属水平中,芽孢杆菌属的丰度随着C/N的增加逐渐上升.综上所述,不添加碳源组的硝化作用强度最强,其余各处理组硝化作用强度随着C/N的升高逐渐降低.     

Co-infections of SARS-CoV-2 with multiple common respiratory pathogens in infected patients

Science China Life Sciences -