Rab GTPases regulating receptor trafficking at the late endosome–lysosome membranes

Lysosomes serve key degradative functions for the turnover of membrane lipids and protein components. Its biogenesis is principally dependent on exocytic traffic from the late endosome via the trans‐Golgi network, and it also receives cargo to be degraded from the endocytic pathway. Membrane trafficking to the late endosome–lysosome is tightly regulated to maintain the amplitude of signalling events and cellular homeostasis. Key coordinators of lysosomal traffic include members of the Rab small GTPase family. Amongst these, Rab7, Rab9 and the more recently studied Rab22B/31 have all been reported to regulate membrane trafficking processed at the late endosome–lysosome system. We discuss what is known about the roles of these Rab proteins and their interacting partners on the regulation of traffic of important receptor proteins such as the epidermal growth factor receptor (EGFR) and the mannose 6‐phosphate receptor (M6PR), in association with the late endosome–lysosome system. Better knowledge of EGFR and M6PR traffic in this regard may aid in understanding the pathological processes, such as oncogenic transformations associated with these receptors. Copyright © 2012 John Wiley & Sons, Ltd.     

江苏省3个自然保护区外来入侵植物的调查及分析

选择位于江苏省内不同生物气候带的连云港云台山森林自然保护区、南京紫金山风景名胜区和宜兴龙池山森林自然保护区为调查区域,采用线路调查、样方调查与走访调查相结合的方法对这3个自然保护区内外来入侵植物的种类及分布现状进行了调查分析.结果显示,云台山森林自然保护区、龙池山森林自然保护区和紫金山风景名胜区内的外来入侵植物分别有13、19和23种,3个保护区总计有外来入侵植物25种,其中共有种11种;在25种外来入侵植物中,菊科(Compositae)种类最多(12种),占总种数的48%;苋科(Amaranthaceae)和玄参科(Scrophulariaceae)种类各有2种;80%的入侵种类来源于美洲,入侵途径以无意传播为主.一年蓬[Erigeron annuus (L. ) Pers. ]的频度最高,达到51.6%;小飞蓬[Conyza canadensis (L. ) Cronq. ]和野茼蒿[Crassocephalum crepidioides (Benth. ) S. Moore]的频度也较高,均在10%以上.部分外来入侵植物已在保护区内建立稳定的繁殖种群,对自然保护区生态环境造成危害,严重威胁着保护区的生物多样性.此外,根据3个保护区内外来入侵植物的分布现状和生态影响,提出了对保护区内外来入侵植物管理与防治的对策和建议.     

白细胞介素-16在脓毒症肝和肺组织中表达的免疫组织化学研究

观察白细胞介素－16（interleukin-16,IL-16)在脓毒症时肝和肺组织中的细胞定位及分布,并探讨其在脓毒症发病中的作用和意义。应用新型敏感的免疫组织化学方法（超敏感－SP法）检测本校近年收集的18例感染、败血症和脓毒症尸检肝和肺组织白细胞介素－16的原位表达,在肝组织中IL－16主要定位于肝窦枯否细胞、单核细胞以及部分中性粒细胞、阳性率达72.3%。肝细胞形态改变主要包括肝窦扩张充血,枯否细胞增生肿胀,肝细胞变性及不同程度的灶性坏死,在肺组织中IL－16定位于肺部质及感染灶内的巨噬细胞,中性粒细胞以及少量淋巴细胞,其阳性率达66.7％。肺组织形态改变主要包括肺泡壁毛细血管扩张充血,间质及肺泡壁内大量炎性细胞浸润,部分肺泡扩张,肺泡壁断裂;可灶性坏死,坏死区肺结构消失,纤维组织增生。同时,观察到IL－16随组织病理变化的加重表达增强的趋势。本研究结果提示IL－16可能在脓毒症所致脏器损害中发挥重要作用。     

新疆准噶尔小胸鳖甲抗冻蛋白基因的克隆和抗冻活性分析

根据GenBank中已发表的昆虫抗冻蛋白基因的保守序列设计引物,利用RT-PCR技术结合3'-RACE扩增的方法,从新疆荒漠昆虫准噶尔小胸鳖甲 Microdera punctipenis dzunarica中获得了长约294 bp不含信号肽的抗冻蛋白cDNA片段,命名为MpAFP5,其全长序列为363 bp(GenBank注册号为：AY821792)。基因测序结果表明, MpAFP5-cDNA片段与加拿大拟步甲Dendroides canadensis AFP 8基因片段、黄粉甲Tenebrio molitor THP 4-9基因片段的核苷酸同源性分别达68.4%和71.8%,氨基酸序列同源性分别达70%和81%。将MpAFP5构建到原核表达载体pGEX4T-1中,重组质粒pGEX4T-1-MpAFP5在大肠杆菌BL21(DE3)中能够表达融合抗冻蛋白,SDS-PAGE分析显示融合蛋白的分子量约为37 kD,Western印迹分析证明MpAFP5在大肠杆菌中正确表达。细菌的抗冻实验结果显示准噶尔小胸鳖甲融合抗冻蛋白对细菌具有显著的抗冻保护作用,保护效果与抗冻蛋白剂量呈正相关性。     

北京地区全新世植被和气候变化研究进展

该文综述了北京地区全新世以来植被演替和气候变化的相关研究资料,这些资料反映了当前阶段对该地区该时段植被与气候环境格局特征的认识。北京地区全新世早期(约12 000–8 000 cal a B.P.)植被为森林草地和/或针叶树占主导的针阔混交林,森林中阔叶树类群逐渐增多,指示了气候由寒冷干燥转为温暖湿润;全新世中期(约8 000–2 000 cal a B.P.前后)植被为暖温带针阔混交林,指示暖湿气候;全新世晚期(约2 000 cal a B.P.以来)转为森林草地和/或针叶树占主导的针阔混交林,气候转向凉干。植被演替反映的湿润度变化与季风区其它地区变化趋势一致。值得注意的是,前人研究揭示北京地区山区与平原中植被类型和类群组成已经出现空间分异。今后如能深入开展定量古气候重建研究,有可能精确描述其气候变化的过程,增进中国不同地理单元同时期气候变化的对比。     

The Influence of Different Factors on Cell Growth and α-tocopherol Content of Culture from Carthamus tinctorius

Calli were induced from root, hypocotyl, cotyledon and flower bud of Carthamtus tinctorius. All calli had the capability to synthesize α-tocopherol. Among these calli, the hvpocotylcallus was better than others in cell growth rate and α-toeopherol content. Culture conditions could intensively influence the growth rate and α-tocopherol production of callus from Carthamus tinctorius. Sucrose (30g/L) was good for callus growth and glucose (30g/L) was good for α-tocopherol accumulation. High concentration (0.55%) of inositol could obviously stimulate both growth rate and α-tocopherol synthesis of callus. The inoculum quantity for best callus growth was 0.035 to 0.067g dry wt/flask (50ml volume). In addition, α-tocopherol content was effectively increased by culture callus in high CO2 concentration. Studies on optimum cuhure conditions of callus culture showed that the callus growth rate, α-tocopherol content and yield were 1.88, 2.03 and 3.30 times respectively as high as of the control by administration of 0.45%–0.55% inositol, 10% coconut milk, 0.1–0.5% casamino acid, 30g/L sucrose and 10g/L glucose.     

小鼠胚胎干细胞分化为血管内皮细胞的永生化研究

本文探讨了小鼠胚胎干细胞（ES细胞）、诱导分化的血管内皮细胞永生化。在体外培养系统中,以维甲酸（RA）和转化生长因子－β1（TGF－β1）诱导小鼠胚胎干细胞（ES细胞）的拟胚体（EB）分化为“圆形细胞”和由这些“圆形细胞”组成的血管样结构。经光学和扫描电镜及免疫荧光等法分析检测,证明组成血管样结构的细胞具有专一性vWF荧光染色,表明是血管内皮样细胞。利用脂质体将人端粒酶催化亚基逆转录酶（hTERT)基因转染诱导分化中的“圆形细胞”。应用Dot-blot,RT－PCR,Western blot及免疫组织化学等方法分析、观察和证明了诱导分化的组成血管样结构的园形细胞和被hTERT基因转染的“圆形”细胞的形态和生物学特性。结果表明,携带hTERT基因的从ES细胞分化来的圆形细胞在体外可大量增殖,持续传代,95％具有血管内皮细胞的一些特有标志和管道化生长特征。因此,通过人端粒酶基因的转染途径可解决由ES细胞诱导分化而来的内皮细胞扩增和永生化问题,为构建组织工程化血管及其它人工血管的内皮化提供种子细胞来源打下基础。     

Telocytes in the Spleen

Telocytes, a novel type of interstitial cells with very long and thin prolongations, have been identified in many organs in mammals. At present, the ultrastructural, immunocytochemical and electrophysiological properties of telocytes in multiple organs have been understood. However, telocytes in spleen, especially their roles in spleen have not been reported. The aim of this study was to investigate the ultrastructure, distribution and immunophenotypes of splenic telocytes. Rat spleen was harvested for the ultrastructure analysis by transmission electron microscopy (TEM). The primary culture of telocytes was performed after combined enzymatic digestion. The characteristic morphology was analyzed by a scanning electron microscopy (SEM). It was shown that telocytes displayed a piriform/spindle/triangular shape with long and slender telopods and extremely long prolongation contracting with surrounding cells in the spleen. Their dynamic profiles of cytoplasmic separation were recorded by the Live Cell Imaging System. The length of telopods was mostly distributing in 20–30 μm, in accordance with normal distribution. Most telocytes had three or two telopods (28.71% and 22.58% respectively). Immunostaining indicated that these cells were positive for vimentin, CD34, nanog and sca-1, but negative for c-kit. These data prove the existence of telocytes in the spleen, which may serve as the experimental base for exploring their roles in the spleen.