Differential sorting and Golgi export requirements for raft-associated and raft-independent apical proteins along the biosynthetic pathway

Sorting signals for apically destined proteins are highly diverse and can be present within the luminal, membrane-associated, and cytoplasmic domains of these proteins. A subset of apical proteins partition into detergent-resistant membranes, and the association of these proteins with glycolipid-enriched microdomains or lipid rafts may be important for their proper targeting. Recently, we observed that raft-associated and raft-independent apical proteins take different routes to the apical surface of polarized Madin-Darby canine kidney cells (Cresawn, K. O., Potter, B. A., Oztan, A., Guerriero, C. J., Ihrke, G., Goldenring, J. R., Apodaca, G., and Weisz, O. A. (2007) EMBO J. 26, 3737-3748). Here we reconstituted in vitro the export of raft-associated and raft-independent markers staged intracellularly at 19 degrees C. Surprisingly, whereas release of the raft-associated protein influenza hemagglutinin was dependent on the addition of an ATP-regenerating system and cytosol, release of a yellow fluorescent protein (YFP)-tagged raft-independent protein (the 75-kDa neurotrophin receptor; YFP-p75) was efficient even in the absence of these constituents. Subsequent studies suggested that YFP-p75 is released from the trans-Golgi network in fragile tubules that do not withstand isolation procedures. Moreover, immunofluorescence analysis revealed that hemagglutinin and YFP-p75 segregate into distinct subdomains of the Golgi complex at 19 degrees C. Our data suggest that raft-associated and raft-independent proteins accumulate at distinct intracellular sites upon low temperature staging, and that upon warming, they exit these compartments in transport carriers that have very different membrane characteristics and morphologies.     

The role of eNOS, iNOS, and NF-kappaB in upregulation and activation of cyclooxygenase-2 and infarct size reduction by atorvastatin

Pretreatment with atorvastatin (ATV) reduces infarct size (IS) and increases myocardial expression of phosphorylated endothelial nitric oxide synthase (p-eNOS), inducible NOS (iNOS), and cyclooxygenase-2 (COX2) in the rat. Inhibiting COX2 abolished the ATV-induced IS limitation without affecting p-eNOS and iNOS expression. We investigated 1) whether 3-day ATV pretreatment limits IS in eNOS(-/-) and iNOS(-/-) mice and 2) whether COX2 expression and/or activation by ATV is eNOS, iNOS, and/or NF-kappaB dependent. Male C57BL/6 wild-type (WT), University of North Carolina eNOS(-/-) and iNOS(-/-) mice received ATV (10 mg.kg(-1).day(-1); ATV(+)) or water alone (ATV(-)) for 3 days. Mice underwent 30 min of coronary artery occlusion and 4 h of reperfusion, or hearts were harvested and subjected to ELISA, immunoblotting, biotin switch, and electrophoretic mobility shift assay. As a result, ATV reduced IS only in the WT mice. ATV increased eNOS, p-eNOS, iNOS, and COX2 levels and activated NF-kappaB in WT mice. It also increased myocardial COX2 activity. In eNOS(-/-) mice, ATV increased COX2 expression but not COX2 activity or iNOS expression. NF-kappaB was not activated by ATV in the eNOS(-/-) mice. In the iNOS(-/-) mice, eNOS and p-eNOS levels were increased but not iNOS and COX2 levels; however, NF-kappaB was activated. In conclusion, both eNOS and iNOS are essential for the IS-limiting effect of ATV. The expression of COX2 by ATV is iNOS, but not eNOS or NF-kappaB, dependent. Activation of COX2 is dependent on iNOS.     

资源冷杉现状及保护措施研究

对资源冷杉的分布现状进行研究,揭示了目前资源冷杉的生存环境、资源数量、生长与自然更新能力,指出了实现有效保护所要面对的问题和应采取的措施。     

磁处理党参药液对小肠平滑肌收缩活动影响的研究

目的 :探讨磁处理党参药液对离体兔小肠平滑肌收缩活动的影响。方法 :通过正常台氏液对照组与磁处理党参药液实验组 ,以及磁处理党参药液组与非磁处理党参药液组进行比较 ,观察对离体兔小肠平滑肌的作用 ,同时观察药液对氯化钡引起离体兔小肠平滑肌收缩活动的影响。结果 :低浓度 ( 5 %、1 0 %、2 0 % )磁处理党参药液对离体兔小肠有轻度抑制作用 ;浓度加大 ( 4 0 %、60 % ) ,有明显促进作用 (P <0 .0 1 ) ;当浓度为 1 0 0 % ,药液有强烈的抑制作用 ,波形几乎呈直线。磁处理药液能解除Bacl2 引起的痉挛性收缩。磁处理与非磁处理党参药液组比较 ,只有浓度 5 %的波幅明显下降 (P <0 .0 1 ) ,其余浓度均无差异显著 (P>0 .0 5 ) ;结论 :磁处理党参药液对小肠平滑肌的收缩活动有明显影响     

激素对不同发育阶段小麦旗叶光合速率调控研究

选择小麦旗叶叶绿素含量的相对稳定期、稳定期末期和速降期3个发育阶段,采用酶联免疫法测定旗叶中ABA／ZRs比值;将ABA、ZRs和二者的混合液引入3个发育阶段植株的蒸腾流,测定激素对不同发育阶段叶片光合速率的影响．结果表明,3个发育阶段植株旗叶中ABA／ZRs比值分别为4．20、41．83和14．40．ABA降低3个阶段叶片光合速率达到零值的时间,分别为49．5、39．1和38．0min;ZRs处理3个发育阶段小麦旗叶的光合速率值降至试验开始零分钟时测得的光合速率值一半的时间,分别为65、49和31min．小麦旗叶的前2个发育阶段为可调和可逆阶段,后1个阶段为不可调和不可逆阶段．     

松墨天牛成虫头部感受器超微结构的观察

扫描电镜观察表明 ,松墨天牛MonochamusalternatusHope成虫头部存在 1 1种感受器。触角有 8种 ,下颚须和下唇须有 6种。栓锥感受器Ⅰ型、毛形感受器Ⅰ型及刺形感受器为触角、下颚须和下唇须共有。触角特有栓锥感受器Ⅱ型、毛形感受器Ⅱ型、锥形感受器以及柱形感受器Ⅰ型和Ⅱ型。下颚须及下唇须特有钟形感受器、坛形感受器和板形感受器。松墨天牛成虫触角感受器在种类、数量和分布上存在性别差异 ,雌雄虫的下颚须和下唇须感受器数量有所不同。     

长江春大豆核心种质构建及分析

利用长江春大豆初选核心种质SSR(simple sequence repeat）标记和农艺性状表型等基础数据,对用不同个体取样方法以及不同数据类型建立的核心种质进行评价,目的是确定中国大豆（Glycine max）核心种质的最佳取样策略提供依据,结果表明,根据SSR分子数据聚类,采用类内随机取样,类内以遗传相似性系数取样以及仅依据遗传相似性系数取样都可用于大豆核心种质构建,但是综合不同评价参数发现,以类内随机取样最佳,类内按遗传相似性系数取样次之,单独以遗传相似性系数取样较差。分析不同SSR等位变异保留比例的遗传多样性指数发现,当保留90%和80%的SSR等位变异时,核心种质具有更高的遗传多样性,由于与SSR分子数据种质遗传关系评价的不一致性,农艺性状等基础数据虽然可用来构建核心种质,但其SSR分子水平代表性相对较低,本研究结果还表明,用不同方法或同一方法不同重复次数取样建立的核心种质具有异质性,且这种异质性随核心种质取样比例的降低而增大,因此,虽然可依据不同数据类型确定相应的方法建立核心种质,但综合表型和分子数据建立的核心种质更具有代表性。     

卵黄抗体经滴鼻途径引起动物免疫反应的研究

研究鸡卵黄免疫球蛋白 (IgY)经滴鼻途径是否引起动物的粘膜免疫反应以及反应的程度。制备抗H3 N2 型流感病毒特异性IgY ,以滴鼻方式免疫实验家兔和豚鼠。实验动物在免疫后不同时期采血 ,检测特异性抗IgY抗体水平。豚鼠以相同IgY静脉攻击 ,观察动物的反应。实验结果表明 ,豚鼠和实验家兔均产生了特异性粘膜免疫反应 ,应慎重采用IgY以滴鼻方式来预防和治疗疾病。     

酸性和碱性土壤新分离的放线菌中线型和环型质粒的检测

从湖南、云南采集的19份酸性土壤样品分离到50株放线菌,在pH4.5和pH7.0的培养基上都能生长.从新疆、青海、云南的14份碱性土壤样品中分离到38株放线菌,在pH10.0和pH7.0的培养基上均能生长.因此,这些菌株属于中度嗜酸或中度嗜碱放线菌.利用脉冲电泳技术和普通凝胶电泳在其中12株放线菌中检测到线型质粒,其中3株放线菌中检测到环型质粒.这是首次在中度嗜酸和中度嗜碱的放线菌中报道线型和环型质粒.