Evidence for sequential action of Rab5 and Rab7 GTPases in prevacuolar organelle partitioning

GTPases of the Rab5 and Rab7 families were shown to control vacuolar sorting but their specific subcellular localization is controversial in plants. Here, we show that both the canonical as well as the plant-specific Rab5 reside at the newly discovered 'late prevacuolar compartment' (LPVC) while Rab7 partitions to the vacuolar membrane when expressed at low levels. Higher expression levels of wild-type Rab5 GTPases but not Rab7 lead to dose-dependent inhibition of biosynthetic vacuolar transport. In the case of Ara6, this included aberrant co-localization with markers for earlier post-Golgi compartments including the trans-Golgi network. However, nucleotide-free mutants of all three GTPases (Rha1, Ara6 and Rab7) cause stronger dose-dependent inhibition of vacuolar sorting. In addition, nucleotide-free Rha1 led to a later maturation defect and co-localization of markers for the prevacuolar compartment (PVC) and the LPVC. The corresponding Rab7 mutant strongly inhibited vacuolar delivery without merging of PVC and LPVC markers. Evidence for functional differentiation of the Rab5 family members is underlined by the fact that mutant Rha1 expression can be suppressed by increasing wild-type Rha1 levels while mutant Ara6 specifically titrates the nucleotide exchange factor Vps9. A model describing the sequential action of Rab5 and Rab7 GTPases is presented in the light of the current observations.     

灌溉对孕穗期冬小麦农田温度的影响

灌溉是抵御和减轻冬小麦晚霜冻危害的有效措施之一。针对黄淮地区2010年4月的一次强降温过程,通过郑州农业气象观测站的灌溉防霜试验,对比分析了冬小麦孕穗期田间空气温度和土壤温度特征。结果表明:在外界环境温度下降时,灌溉可以提高田间最低气温0.1～0.6℃,增温效应主要集中在地上5cm处,灌溉可减少气温≤0℃的持续时间1～2h;对土壤温度的影响随着深度而存在差异,0cm土壤温度以增加为主,5～20cm土壤以降温效应为主;灌溉减小了气温和0～5cm土壤温度的变异系数和平均相对变率,而增大了10～20cm土壤温度的变异系数和相对变率;灌溉引起的温度差异只在15和20cm土壤处比较显著,其余各层温度差异并不明显。     

Scavenger receptor class B type I localizes to a late endosomal compartment

Scavenger receptor class B type I (SR-BI) has an established role in mediating the selective uptake of cholesterol from HDL in hepatocytes, steroidogenic cells, and other tissues. SR-BI is present on the plasma membrane but also localizes to stable intracellular compartments of unknown function. Using indirect immunofluorescence and subcellular fractionation, we have investigated the subcellular distribution of SR-BI. We report that red fluorescent protein-tagged mouse SR-BI (RFP-mSR-BI) colocalizes with the late endosomal and lysosomal markers, Rab7, LBPA, and Rab9. In addition, endogenous SR-BI is also found on lysosomes and colocalizes with LAMP-2 in primary hepatocytes. Furthermore, we demonstrate that the trafficking of SR-BI through these compartments is Rab7 dependent. Interestingly, filipin staining indicates accumulation of lysosomal cholesterol in SR-BI-deficient ((-/-)) as compared with wild-type hepatocytes. In addition to its role as a plasma membrane receptor, SR-BI may function in cholesterol trafficking from late endosomes/lysosomes.     

Identification of quantitative trait loci for four morphologic traits under water stress in rice （Oryza sativa L.）

Late season drought coinciding with the rice booting to heading stage affects the development of plant height,panicle exsertion,and flag leaf size,and causes significant yield loss.In this study,a recombinant inbred line population derived from a cross between paddy and upland cultivars was used for data collection of the morphologic traits under well water and drought stress conditions.bought stress was applied at the stage of panicle initiation in the field in 2002 and at the booting stage in PVC pipes in 2003.The data from stress con ditions and their ratios(tait measured under stress condition/trait measured under well water condition)or differences(trait measured under stress condition minus trait measured under well water condition)were used for OTL analysis.Totally,17 and 36 QTLs for these traits were identified in 2002 and 2003,respectively,which explained a range of 2.58%-29.82%Of the phenotypic variation.Among them,six QTLs were commonly identified in the two years,suggesting that the drought stress in the two years was different.The genetic basis of these traits will provide useful information for improving rice late season drought resistance,and their application as indirect indices in rice late season drought resistance screening was also discussed.     

False belief reasoning in the brain: An ERP study

Understanding others mind and interpersonal interaction are the cognitive basis of successful social interactions. People's mental states and behaviors rely on their holding beliefs for self and others. To investigate the neural substrates of false belief reasoning, the 32 channels event-related potentials (ERP) of 14 normal adults were measured while they understood false-belief and true belief used de-ceptive appearance task. After onset of the false-belief or true-belief questions, N100, P200 and late negative component (LNC) were elicited at centro-frontal sites. Compared with true belief, false belief reasoning elicited significant declined LNC in the time window from 400 to 800 ms. The source analysis of difference wave (False minus True) showed a dipole located in the middle cingulated cortex. These findings show that false belief reasoning probably included inhibitive process.     

RAGE signaling contributes to neuroinflammation in infantile neuronal ceroid lipofuscinosis

Palmitoyl-protein thioesterase-1 (PPT1) deficiency causes infantile neuronal ceroid lipofuscinosis (INCL), a devastating childhood neurodegenerative storage disorder. We previously reported that neuronal apoptosis in INCL is mediated by endoplasmic reticulum-stress. ER-stress disrupts Ca²⁺-homeostasis and stimulates the expression of Ca²⁺-binding proteins. We report here that in the PPT1-deficient human and mouse brain the levels of S100B, a Ca²⁺-binding protein, and its receptor, RAGE (receptor for advanced glycation end-products) are elevated. We further demonstrate that activation of RAGE signaling in astroglial cells mediates pro-inflammatory cytokine production, which is inhibited by SiRNA-mediated suppression of RAGE expression. We propose that RAGE signaling contributes to neuroinflammation in INCL.     

云南禄丰古猿地点的松鼠类化石

记述了云南禄丰晚中新世石灰坝古猿地点发现的松鼠科化石。禄丰石灰坝动物群的松鼠动物共有 7属 7种 :地松鼠Sciurotamiaswangisp .nov .,树松鼠Tamiopssp .、Callosciurussp .、Dremomysprimitivussp .nov .和飞松鼠Miopetauristaasiaticasp .nov .、Hylopetodondianensegen .etsp.nov.、Pteromyinaegen.etsp .indet.。该动物群松鼠类动物的组成以树松鼠和飞松鼠为主 ,反映了较为湿润的热带—亚热带森林环境。在动物地理上 ,其成员几乎局限于东南亚分布 ,具有浓厚的现代东洋界色彩     

始鼠化石在甘肃省党河地区上渐新统的发现

<正>始鼠科(Ｅｏｍｙｉｄａｅ)是一类已绝灭的小型的鼠类,在古近纪和新近纪时广布全北区,以北美(中始新世—晚中新世)和欧洲(早渐新世—晚上新世)发现的化石较丰富。过去在亚洲发现的始鼠化石极少。亚洲的第一个始鼠化石是１９８２年才发现的(郑绍华等,１９８２)。２０世纪９０年代以来,在亚洲陆续发现了一些始鼠化石,表明从中始新世到上新世时在亚洲已有始鼠生存过(Ｗａｎｇ ａｎｄ Ｅｍｒｙ,１９９０;Ｑｉｕ,１９９４,１９９６;Ｔｏｍｉｄａａｎｄ Ｓｅｔｏｇｕｃｈｉ,１９９４;Ｅｍｒｙ ｅｔ