A quadratic correlation between long‐term mean group size and group density in a cooperatively breeding passerine

Both mean group size (MGS) and mean group density (MGD) are critical indices to characterize a population of cooperatively breeding birds. When a population reaches its carrying capacity, both long‐term MGS and long‐term MGD will remain relatively stable. However, there has been little study of how these two variables relate. The Masked laughingthrush Garrulax perspicillatus is a cooperatively breeding bird living in fragmented habitats. During 2010 and 2012‐2016, we used song playback to observe and confirm the group sizes and territory ranges of the birds and the data of bird presence to determine habitat suitability. By grouping the nearest territories according to their geographical coordinates, we divided the whole study area into 12 subareas and the whole population into 12 subpopulations. Then, we calculated both MGS and MGD for different time durations for each subpopulation. Finally, using MGD as independent variable and MGS as the dependent variable, we explored the correlations between MGS and MGD by fitting quadratic functions and modeling quadratic regression. Both MGS and MGD were averaged for different time durations and were cross‐related. Our results show that the MGS for more than 2 years significantly correlated with MGD for more than 3 years in a reverse parabolic shape, differing from that of short‐term effects. Our findings suggest that long‐term MGD is a better predictor of long‐term habitat quality and that long‐term MGS is determined by long‐term habitat quality in Masked Laughingthrushes. Based on above findings, we can infer that: (1) Long‐term habitat quality determines the long‐term MGS, but it sets no prerequisite for the status and source of group members; (2) Long‐term MGS in certain populations is adapted to the corresponding level of long‐term habitat quality, it facilitates us to predict the helper effects on current or future survival or reproduction in different situations. These findings and inferences are both helpful for us to understand the evolution of cooperative breeding.     

细胞色素bc_1复合物的喇曼光谱研究

对提纯的细胞色素ｂｃ１复合物的氧化态和底物琥珀酸还原态两个样品进行了共振喇曼和富立叶喇曼光谱测定和比较。琥珀酸还原态与氧化态的共振谱比较明显有变化,而富立叶红外谱没有什么差别。说明呼吸链的电子传递体在氧化态与还原态交替变化进行电子传递时,蛋白总体构象不发生大的改变,而活性中心血红素辅基局部构象变化很大。     

Molecular and nanoparticle postcolumn reagents for assay of low-molecular-mass biothiols using high-performance liquid chromatography

Determination of low-molecular-mass (LMM) biothiols in biological matrixes is of importance in the studies of their related bio-processes and for the clinical diagnostics of a variety of diseases. Standard method for the assay of the small biothiols is in demand. Postcolumn techniques used in high-performance liquid chromatography (HPLC) allow automation of the derivatization step and, therefore, are suitable for standardization of HPLC analysis. This paper gives an overview of the existing reaction systems useful for the postcolumn assay of the LMM biothiol molecules in conjunction with HPLC. The postcolumn reagents are classified by the types of their reactions with thiol-containing compounds. The chemical reactivity and selectivity as well as the spectroscopic characteristics of the postcolumn reagents have been addressed. The emerging strategies of using nanoparticles as thiol-reactive reagents and their applications in postcolumn detection of the LMM biothiols have also been discussed in detail.     

蓖麻根提取物对HepG2,NCI-H460和SGC-7901细胞增殖及凋亡作用的影响

探讨蓖麻根不同提取物对肝癌HepG2细胞株、肺癌NCI-H460细胞株和胃癌SGC-7901细胞株增殖及其凋亡的影响.采用MTT法检测蓖麻根不同提取物处理48h、72h对HepG2细胞、NCI-H460细胞和SGC-7901细胞增殖的抑制率;Hoechst 33258荧光染料染色法观察HepG2细胞凋亡,流式细胞术检测...     

Seroprevalence of pandemic (H1N1) 2009 in pregnant women in China: an observational study

Background

We investigated the seropositive rates and persistence of antibody against pandemic (H1N1) 2009 virus (pH1N1) in pregnant women and voluntary blood donors after the second wave of the pandemic in Nanjing, China.

Methodology/Principal Findings

Serum samples of unvaccinated pregnant women (n = 720) and voluntary blood donors (n = 320) were collected after the second wave of 2009 pandemic in Nanjing. All samples were tested against pH1N1 strain (A/California/7/2009) with hemagglutination inhibition assay. A significant decline in seropositive rates, from above 50% to about 20%, was observed in pregnant women and voluntary blood donors fifteen weeks after the second wave of the pandemic. A quarter of the samples were tested against a seasonal H1N1 strain (A/Brisbane/59/2007). The antibody titers against pH1N1 strain were found to correlate positively with those against seasonal H1N1 strain. The correlation was modest but statistically significant.

Conclusions and Significance

The high seropositive rates in both pregnant women and voluntary blood donors suggested that the pH1N1 virus had widely spread in these two populations. Immunity derived from natural infection seemed not to be persistent well.     

细小病毒H-1对人肝癌移植瘤的抑制及其组织学与组织化学的研究

本文用人肝癌裸小鼠QGY-9204移植模型为材料,进行了细小病毒H-1抑瘤的组织学、组织化学及分子生物学研究。以两种不同剂量(5×10~7PFU和5×10~8PFU)的H-1进行瘤内注射,发现注入H-1后的肿瘤生长速率明显缓于对照组,且5×10~7PFU的H-1注入即可产生这一效应。以1×10~8PFU H-1注入瘤内,不同时间进行组织切片观察,发现从感染后第3天起瘤内开始出现坏死,且随感染时间的延长坏死范围也逐渐扩大,而对照组在该期间均未见此变化。电镜结果也表明,在受损的肿瘤细胞内有H-1病毒颗粒存在。PCR反应和ABC免疫染色显示在感染后的肿瘤组织内也有H-1 DNA扩增和NS-1蛋白表达,并且两者显示的时间与组织内坏死的过程相一致。这些结果提示,细小病毒H-1通过它的DNA复制和NS-1蛋白的表达以促进肿瘤的坏死,从而达到肿瘤抑制和裂解。     

Loss of chloroplast-localized NAD kinase causes ROS stress in Arabidopsis thaliana

Journal of Plant Research - Chloroplast-localized NAD kinase (NADK2) is responsible for the production of NADP+, which is an electron acceptor in the linear electron flow of photosynthesis. The...     

裂叶沙参和泡沙参种群有性生殖和无性繁殖的比较

通过对裂叶沙参(Adenophora lobophylla Hong)和泡沙参(A.potaninii Korsh.)种群有性生殖和无性繁殖特性的对比,揭示濒危植物裂叶沙参的种群内部致濒机制。结果表明:裂叶沙参种群幼苗抢占草本层上层空间能力弱于泡沙参种群;裂叶沙参种群是以相对长的生殖期和高产籽量来适应环境;裂叶沙参种群开花结实量虽高于泡沙参种群,但其中成熟种子少,种子质量差,致使其种群由种子到一年生幼苗的转化率极低,并且幼苗生活力弱,是导致其种群濒危的重要内部原因。裂叶沙参种群除有性生殖外还兼有较弱的无性繁殖,是对其有性生殖的一个重要补充。     

羊草种群生物量生殖分配的初步研究

对羊草种群生物量生殖分配的研究表明,在生殖生长过程中,种群用于根茎和营养生长的生物量生殖分配占有绝对优势比例,而用于有性生殖的生物量生殖分配比例较小,在10%以下。在羊草种群构件生物量生殖分配中,根茎和营养枝的叶占有较大比例(20%～40%),而用于有性繁殖体种子生产的比例很小,在1.5%以下。对有性繁殖的小比例投资是导致羊草种群有性繁殖体种子产量低的重要原因.     

表达O型口蹄疫病毒VPl基因的重组病毒BHV-1的构建与鉴定

[目的]为了构建表达口蹄疫病毒(O/china/99)VP1基因的牛疱疹病毒1型,将人工合成的口蹄疫病毒VP1基因插入到巨细胞病毒(CMV)启动子之下构建gE基因缺失转移载体.[方法]利用磷酸钙介导转染法将该转移载体与亲本病毒BHV-1/gE-/LacZ+的基因组DNA共转染牛鼻甲细胞后收获增殖的病毒.通过筛选白色病毒蚀斑,得到重组病毒BHV-1/gE-/VP1.[结果]PCR检测结果表明VP1基因已经插入到了重组病毒BHV-1/gE-的基因组中,间接免疫荧光试验和Westem blot证实了BHV-1/gE-/VP1中的VP1基因在感染的细胞中获得了表达.[结论]本研究成功地构建了表达口蹄疫病毒VP1基因的重组病毒BHV-1/gE-/VP1,为研制口蹄疫及其他重要牛传染病的BHV-1病毒载体疫苗奠定了基础.