NMR structure of hsp12, a protein induced by and required for dietary restriction-induced lifespan extension in yeast

Dietary restriction (DR) extends lifespan in yeast, worms, flies and mammals, suggesting that it may act via conserved processes. However, the downstream mechanisms by which DR increases lifespan remain unclear. We used a gel based proteomic strategy to identify proteins whose expression was induced by DR in yeast and thus may correlate with longevity. One protein up-regulated by DR was Hsp12, a small heat shock protein induced by various manipulations known to retard ageing. Lifespan extension by growth on 0.5% glucose (DR) was abolished in an hsp12Δ strain, indicating that Hsp12 is essential for the longevity effect of DR. In contrast, deletion of HSP12 had no effect on growth under DR conditions or a variety of environmental stresses, indicating that the effect of Hsp12 on lifespan is not due to increased general stress resistance. Unlike other small heat shock proteins, recombinant Hsp12 displayed negligible in vitro molecular chaperone activity, suggesting that its cellular function does not involve preventing protein aggregation. NMR analysis indicated that Hsp12 is monomeric and intrinsically unfolded in solution, but switches to a 4-helical conformation upon binding to membrane-mimetic SDS micelles. The structure of micelle-bound Hsp12 reported here is consistent with its recently proposed function as a membrane-stabilising 'lipid chaperone'. Taken together, our data suggest that DR-induced Hsp12 expression contributes to lifespan extension, possibly via membrane alterations.     

Receptor activator of NF-kappaB and podocytes: towards a function of a novel receptor-ligand pair in the survival response of podocyte injury

Background

Glomerulosclerosis correlates with reduction in podocyte number that occurs through mechanisms which include apoptosis. Podocyte injury or podocyte loss in the renal glomerulus has been proposed as the crucial mechanism in the development of glomerulosclerosis. However, the mechanism by which podocytes respond to injury is poorly understood. TNF and TNF receptor superfamilies are important in the pathogenesis of podocyte injury and apoptosis. The ligand of receptor activator of NF-kappaB (RANKL) and receptor activator of NF-kappaB (RANK) are members of the TNF and receptor superfamilies. We investigated whether RANK - RANKL is a receptor - ligand complex for podocytes responding to injury.

Methodology/Principal Findings

In this study, RANKL and RANK were examined in human podocyte diseases and a rat model of puromycin aminonucleoside nephrosis (PAN). Compared with controls, RANK and RANKL were increased in both human podocyte diseases and the rat PAN model; double immunofluorescence staining revealed that RANK protein expression was mainly attributed to podocytes. Immunoelectron microscopy showed that RANK was localized predominantly at the top of the foot process membrane and the cytoplasm of rat podocyte. In addition, RANK was upregulated in mouse podocytes in vitro after injury induced by puromycin aminonucleoside (PA). Knockdown of RANK expression by small interference RNA (siRNA) exacerbated podocyte apoptosis induced by PA. However, RANKL inhibited significantly the apoptosis of podocytes induced by PA.

Conclusions/Significance

These findings suggest the increase in RANK–RANKL expression is a response to podocyte injury, and RANK–RANKL may be a novel receptor–ligand complex for the survival response during podocyte injury.     

Renalase's Expression and Distribution in Renal Tissue and Cells

To study renalase''s expression and distribution in renal tissues and cells, renalase coded DNA vaccine was constructed, and anti-renalase monoclonal antibodies were produced using DNA immunization and hybridoma technique, followed by further investigation with immunological testing and western blotting to detect the expression and distribution of renalase among the renal tissue and cells. Anti-renalase monoclonal antibodies were successfully prepared by using DNA immunization technique. Further studies with anti-renalase monoclonal antibody showed that renalase expressed in glomeruli, tubule, mesangial cells, podocytes, renal tubule epithelial cells and its cells supernatant. Renalase is wildly expressed in kidney, including glomeruli, tubule, mesangial cells, podocytes and tubule epithelial cells, and may be secreted by tubule epithelial cells primarily.     

Dissection of human MiRNA regulatory influence to subpathway

The global insight into the relationships between miRNAs and their regulatory influences remains poorly understood. And most of complex diseases may be attributed to certain local areas of pathway (subpathway) instead of the entire pathway. Here, we reviewed the studies on miRNA regulations to pathways and constructed a bipartite miRNAs and subpathways network for systematic analyzing the miRNA regulatory influences to subpathways. We found that a small fraction of miRNAs were global regulators, environmental information processing pathways were preferentially regulated by miRNAs, and miRNAs had synergistic effect on regulating group of subpathways with similar function. Integrating the disease states of miRNAs, we also found that disease miRNAs regulated more subpathways than nondisease miRNAs, and for all miRNAs, the number of regulated subpathways was not in proportion to the number of the related diseases. Therefore, the study not only provided a global view on the relationships among disease, miRNA and subpathway, but also uncovered the function aspects of miRNA regulations and potential pathogenesis of complex diseases. A web server to query, visualize and download for all the data can be freely accessed at http://bioinfo.hrbmu.edu.cn/miR2Subpath.     

石竹属植物叶表皮特征及其系统学意义

用光学显微镜和扫描电镜,对石竹属12个种的植物叶表皮特征进行观察,统计并测量叶表皮气孔大小、气孔密度及气孔指数。结果表明,石竹属植物叶表皮细胞形态(表面观)为长方形和不规则多边形。乳突只存在于针叶石竹、高石竹和细茎石竹中。按气孔形状可将其分为了3个类型:椭圆形、卵圆形和长方形。研究结果对石竹属的系统分类和种间亲缘关系研究具有一定的参考价值。     

二氧化氯浸泡对双孢蘑菇褐变的抑制效应及其机理分析

以‘W2000’双孢蘑菇为试验材料,设清水(CK)和ClO2浸泡(120mg·L-1)2个处理,研究ClO2浸泡处理在低温贮藏条件下对双孢蘑菇采后品质、生理及相关酶活性的影响。结果显示:ClO2浸泡处理配合0℃低温贮藏可显著降低双孢蘑菇的呼吸强度,推迟呼吸高峰的出现时间,呼吸强度较CK降低29.2%,并使呼吸高峰推迟5d出现;同时能够有效抑制子实体多酚氧化酶(PPO)和过氧化物酶(POD)的活性,控制酚类氧化产物的积累,减缓子实体褐化进程,贮藏20d时,处理的总酚含量仅为0.81μmol/mg。另外,ClO2处理还可延缓子实体硬度的下降,保持其可溶性固形物的含量,并抑制开伞,有效延长双孢蘑菇的贮藏期。研究表明,ClO2处理+低温贮藏对双孢蘑菇具有较理想的保鲜效应,可有效保持双孢蘑菇的外观和营养品质,提高商品价值,具有一定的实际应用价值。     

马铃薯杂种F1的SSR鉴定

为选育抗黑痣病、高产优质的马铃薯新品种,选用引进品种‘大西洋’分别与‘陇薯6号’、‘陇薯7号’杂交,获得了杂种F1代,利用SSR标记技术对‘大西洋’与‘陇薯6号’的42个杂种F1、‘大西洋’与‘陇薯7号’的9个杂种F1单株进行了鉴定。从59对SSR引物中筛选出2对在亲本间存在差异、扩增稳定、条带清晰的引物S184和STM1049,用于‘大西洋’ב陇薯6号’杂种F1、‘大西洋’ב陇薯7号’杂种F1及其亲本的基因组DNA扩增。SSR带型分析显示,杂种F1的SSR带型呈双亲互补型、缺失型、父本型和母本型4类,依据带型特征鉴定出供试的51个马铃薯杂种F1单株均为真杂种,表明SSR分子标记技术用于马铃薯杂种真实性鉴定是可行的。该研究可为进一步开展马铃薯杂交后代目标性状优异株系选育提供依据。     

早熟油菜成花相关基因LFY的克隆与分析

以甘蓝型油菜晚熟品种RG-8的早熟突变体RG-8M为材料,通过同源克隆法得到1个LEAFY(LFY)同源基因,命名为BnLFY。该基因cDNA全长为1 310bp,包含1个长为1 248bp的开放阅读框,编码415个氨基酸。序列分析表明,推测的氨基酸序列含双子叶植物LFY类蛋白特有的N端脯氨酸富集区、中央酸性区、亮氨酸拉链结构以及富含赖氨酸与精氨酸的碱性区;且与几种十字花科植物LFY类蛋白的氨基酸序列一致性均在84%以上。转录表达分析表明,BnLFY基因在油菜中为组成型表达。