The affinity of human RANK binding to its ligand RANKL

Receptor activator of nuclear factor-kappa B (RANK) and its ligand, RANKL play critical roles in bone re-modeling, immune function, vascular disease and mammary gland development. To study the interaction of RANK and RANKL, we have expressed both extracellular domain of RANK and ectodomain of RANKL using Escherichia coli expression system. RANK was expressed as an inclusion body first which properly refolded later, while RANKL was initially produced as a GST fusion protein, after which the GST was removed by enzyme digestion. Soluble RANK existed as a monomer while RANKL was seen as a trimer in solution, demonstrated by gel filtration chromatography and cross-linking experiment. The recombinant RANK and RANKL could bind to each other and the binding affinity of RANKL for RANK was measured with surface plasmon resonance technology and K_D value is about 1.09 × 10⁻¹⁰ M.     

Seasonal occurrence of helminths in the anadromous fish Coilia nasus (Engraulidae): parasite indicators of fish migratory movements

To understand the seasonal migration of the anadromous Coilia nasus , we attempted to identify the parasites infecting C. nasus and determine their seasonal occurrence. From June 2007 to July 2008, a survey of 775 C. nasus individuals from the estuary of the Yangtze River and the coast of the East China Sea revealed more than 7,300 parasites associated with the gills and alimentary tracts of C. nasus . The following 6 helminth taxa were identified, i.e., the monogeneans Heteromazocraes lingmueni and Helciferus tenuis, the digenean Elytrophallus coiliae, the acanthocephalan Acanthosentis cheni , and larvae of the nematodes Anisakis simplex and Contracaecum sp., all of which are marine or brackish-water parasites. The absence of freshwater helminths suggested that the parasites acquired in freshwater may have been accidentally, and easily, lost by the time the fish had reached the estuary and coast. Contrary to seasonal occurrence of the parasites' life cycles, the lowest mean abundance and prevalence of H. lingmueni and A. cheni occurred in August, which suggested the immigration of C. nasus from freshwater to the Yangtze estuary, with lower parasite burdens. The highest mean abundance and prevalence of the nematodes A. simplex and Contracaecum sp. in May and June, and the lowest in August, indicated the arrival of the fish from the coast and the Yangtze River, to the estuary, respectively. These findings suggested that a majority of the fish prepared for spawning migration in the estuary in spring and early summer and returned to the estuary after spawning in the lower and middle reaches of the Yangtze River in late summer.     

对TMV不同抗性番茄品种的叶绿体DNA限制性内切酶酶谱分析

选用对TMV有抗性和敏感的番茄品种、制备其ct-DNA, 用限制性内切酶BumHI、EcoRI和PstI完全酶解, 三种酶切图谱与前人报道一致, 由酶切片段计算番茄ct-DNA。分子量约为156.9kb。比较抗性和敏感品种的ct-DNA图谱, 发现三种酶切图谱均存在差异, 但由差异片段计算分子量之和又很除近。我们推测这是由于检基顺序变异或小段DNA顺序插入或缺失所造成, 由此证明, 叶绿体基因组与核中的TMV抗性基因, 共同决定着植物体对TMV的抗性。     

Nitrate increases cisplatin chemosensitivity of oral squamous cell carcinoma via REDD1/AKT signaling pathway

Although cisplatin is one of the chemotherapeutics most frequently used in oral squamous cell carcinoma (OSCC) treatment,it exerts multiple side effects and poo...     

体液蛋白质组学的研究和应用

蛋白质组学是目前生命科学的研究热点之一.体液中的蛋白质是来源于与其密切接触组织或者细胞的分泌或渗漏,体液蛋白质组的变化能反映这些组织的生理或者病理改变,因此以寻找疾病相关生物标记为主要目标的比较蛋白质组学是蛋白质组学研究的核心内容之一.对近年来各种体液蛋白质组学的研究状况和应用及存在挑战作一综述.     

二氮嗪对自发性高血压大鼠心功能及心肌ERK和JNK表达的影响

目的:探讨二氮嗪对离体自发性高血压大鼠心脏缺血/再灌注心功能及心肌组织ERK和JNK表达的影响及可能机制。方法:雄性自发性高血压大鼠取心行Langendorff灌流。实验分为5组(n=6/组):对照组(Con)在平衡后继续灌流40min,全心缺血25min,复灌30min。其余各组除全心缺血前处理不同外,余均同对照组。缺血预处理组(IP)2次给予5min缺血+10min复灌,二氮嗪预处理组(DP)给予2次含50μmol·L-1二氮嗪的K-H液10min后给不含二氮嗪的K-H液5min,5-HD、5-HD+DP组则在平衡后给予10min150μmol·L-1线粒体KATP阻断剂5-HD,余同Con及DP组。结果:IP组及DP组复灌末左室发展压、+dP/dtmax和-dP/dtmax的恢复率均高于Con组(P<0.01),但两组左室舒张末期压恢复率低于Con组(P<0.01);5-HD能拮抗二氮嗪引起的心功能指标的改善。复灌末IP、DP及5-HD+DP组ERK表达增加。IP组及DP组心肌的JNK表达低于Con组(P<0.05),5-HD+DP组JNK表达显著高于DP组。结论:二氮嗪预处理对离体自发性高血压大鼠心肌缺血/再灌注损伤有保护作用,此保护作用可能与ERK的表达增加及JNK表达减少有关。     

BnaC.Tic40, a plastid inner membrane translocon originating from Brassica oleracea, is essential for tapetal function and microspore development in Brassica napus

Here, we describe the characteristics of a Brassica napus male sterile mutant 7365A with loss of the BnMs3 gene, which exhibits abnormal enlargement of the tapetal cells during meiosis. Later in development, the absence of the BnMs3 gene in the mutant results in a loss of the secretory function of the tapetum, as suggested by abortive callose dissolution and retarded tapetal degradation. The BnaC.Tic40 gene (equivalent to BnMs3) was isolated by a map-based cloning approach and was confirmed by genetic complementation. Sequence analyses suggested that BnaC.Tic40 originated from BolC.Tic40 on the Brassica oleracea linkage group C9, whereas its allele Bnms3 was derived from BraA.Tic40 on the Brassica rapa linkage group A10. The BnaC.Tic40 gene is highly expressed in the tapetum and encodes a putative plastid inner envelope membrane translocon, Tic40, which is localized into the chloroplast. Transmission electron microscopy (TEM) and lipid staining analyses suggested that BnaC.Tic40 is a key factor in controlling lipid accumulation in the tapetal plastids. These data indicate that BnaC.Tic40 participates in specific protein translocation across the inner envelope membrane in the tapetal plastid, which is required for tapetal development and function.     

Time-dependent cross ratio estimation for bivariate failure times

In the analysis of bivariate correlated failure time data, it is important to measure the strength of association among the correlated failure times. One commonly used measure is the cross ratio. Motivated by Cox's partial likelihood idea, we propose a novel parametric cross ratio estimator that is a flexible continuous function of both components of the bivariate survival times. We show that the proposed estimator is consistent and asymptotically normal. Its finite sample performance is examined using simulation studies, and it is applied to the Australian twin data.     

Relationships between musk extraction, social rank and tail-rubbing in male Alpine musk deer, Moschus sifanicus

Musk deer (Moschus spp.) are small, solitary forest ruminants well-known for the musk secreted by adult males. Because of illegal hunting and habitat degradation and loss, the five species of musk deer are classified as endangered. Musk deer farming has been a positive example of ex situ conservation, maintaining deer numbers whilst sustaining musk production. This study was conducted at the Xinglongshan Musk Deer Farm in Gansu Province in northwest China, and was designed to explore the relationships among musk extraction, fighting ability and social rank in captive, male alpine musk deer (Moschus sifanicus). Results showed that musk production was related to a male’s rank in the dominance hierarchy. Males in the middle rank of the dominance hierarchy tended to produce more musk than deer of higher and lower ranks. This is due to the time-energy budgeting patterns and captive stress of males with different status in the dominance hierarchy. That is, high-ranking males need to budget more time and energy to maintain their higher rank, while low-ranking males are exposed to more aggression from higher-ranking individuals, thus limiting their access to resources such as food and shelter. Accordingly, high-ranking and low-ranking males endured more stress than middle-ranking males, negatively affecting their annual musk production. Supporting the correlation between musk production and the frequency of tail-rubbing behavior was not significant, average musk extraction could not be predicted based on the frequency of tail-rubbing alone. Status in the dominance hierarchy, however, was positively correlated with tail-rubbing frequency, with males of higher rank tending to tail-rub more frequently. Conflict winners tended to initiate tail-rubbing after the conflict; tail-rubbing accounted for 83.33% of the post-conflict behavior expressed by the winner. Tail-rubbing was one of the behavioral rewards of winning a conflict and was also related to releasing aggression; not solely for scent marking territory and trails. Based on the results of this study, there was no direct relationship between musk production and captive males’ status in the dominance hierarchy (and, therefore, in the intensity of aggression displayed). If the sole aim of musk deer farms is to domesticate musk deer for maximum production of musk, we suggest that highly aggressive males be removed from the population. Musk production will remain unchanged, however, aggression level and intensity of fighting could be lessened thus reducing farming costs.