木本植物季节性休眠的分子机制

季节性休眠是多年生木本植物在生态和进化上的一种"权衡"机制,也是植物界多样性生存策略的组成部分.木本植物的休眠反应首先是Ca2+作为信号物质诱导CO/FT基因的表达,进而引起与休眠相关的DAM基因的表达;而低温可以诱导休眠的发生,冷诱导表达的基因CBF和COR在休眠期间也有表达;而与逆境相关的蛋白如脱水蛋白、抗冻蛋白、热激蛋白和热稳定蛋白等也与休眠反应有密切的关系.本文就与木本植物季节性休眠相关的分子机制进行了综述.     

植物内生细菌在植物修复重金属污染土壤中的应用

土壤重金属污染是威胁人群健康和经济可持续发展的重要环境问题。植物修复具有经济、环保等特点,已成为治理重金属污染土壤的重要技术。如何提高植物对重金属的抗性、促进植物生长是影响植物修复效率的关键之一。内生菌群-植物共生关系在此方面具有独特优势。其中,植物内生细菌可改善植物营养、降低植物病菌感染、影响酶活性,以及分泌激素、含铁载体和有机配位体等,进而提高超积累植物对重金属的吸收作用。本文综述了近年来国内外关于抗重金属植物内生细菌筛选与应用的研究进展,分析了内生细菌促进植物生长、增强植物对重金属抗性、促进重金属向茎叶转移的机理,阐述了植物内生细菌在重金属污染土壤修复中的应用前景与研究重点。     

克氏原螯虾的入侵生态学研究进展

克氏原螯虾(Procambarus clarkii)原产于美国南部和墨西哥北部,是一个著名入侵物种,作为一种水产经济资源物种在世界各地扩散。克氏原螯虾抗逆性强,所具有的广泛生境适应性、生长迅速、高生殖率等特点使它们迅速建立野生种群。近10余年的研究认为,克氏原螯虾通过捕食和资源竞争等机制严重威胁引入地的水生植物、无脊椎动物、两栖类等的生存,显著降低引入地的生物多样性。当前,由于克氏原螯虾的经济价值高,它会借助于人力的作用而继续扩散。为认清和减少克氏原螯虾对引入地的生态影响,应加强以下方面的研究:1)在中国开展克氏原螯虾的生态危害的调查和研究;2)克氏原螯虾种群调节和控制对策研究;3)被入侵地的生态恢复工作。     

八氯腺苷诱导SH-SY5Y和SK-N-SH细胞G2/M期阻滞的分子机制不同

为探索八氯腺苷的抗肿瘤作用机制,以神经母细胞瘤SH-SY5Y和SK-N-SH细胞为对象,采用四唑盐比色实验（MTT法）证明,八氯腺苷具有明显的抑制肿瘤细胞增殖的作用,这种抑制作用呈剂量-时间依赖性.流式细胞分析显示,10 μmol/L八氯腺苷作用48 h后可导致靶细胞生长停滞于G ^₂/M期;SH-SY5Y细胞发生明显细胞凋亡,但SK-N-SH细胞却未见凋亡.Hoechst 33342染色显示,SK-N-SH细胞发生了核分裂异常.蛋白质免疫印迹分析证明,10 μmol/L 八氯腺苷处理SH SY5Y 48～72 h后,G^₂检验点调节蛋白ATM、Chk1、Cdc25C和Cdc2磷酸化形式明显上调,同时伴有caspase-3的激活,提示SH-SY5Y细胞发生了G^₂检验点通路和细胞凋亡途径的激活.与SH-SY5Y细胞不同,在SK-N-SH细胞中,八氯腺苷处理24～96 h时,磷酸化ATM、磷酸化Chk1/Chk2、磷酸化Cdc25C以及磷酸化Cdc2的水平呈现逐渐降低的趋势.结果提示,SK-N-SH细胞在八氯腺苷处理后发生了G^₂检验点失败.蛋白质免疫印迹分析还显示,八氯腺苷可诱导p53在SH-SY5Y细胞的表达,但却不能影响SK—N-SH细胞的p53组成性表达水平.p21在SK-N-SH的组成性表达随八氯腺苷处理时间延长而逐渐减少,但在处理前后的SH-SY5Y细胞均未检测到p21蛋白的表达.上述实验结果提示,八氯腺苷抑制两种细胞增殖的机制不同：在SH-SY5Y细胞,八氯腺苷可激活ATM-Chk-Cdc25C-Cdc2/cyclin途径和凋亡通路,使细胞发生G_²/M期阻滞和细胞凋亡;在SK-N-SH细胞,八氯腺苷诱导G^₂检验点失败,导致细胞阻滞在有丝分裂期,并发生有丝分裂异常.2种不同的细胞命运可能还与p53和p21表达不同有关.     

魏氏拟尾柱虫休眠包囊及其细胞器超微结构的观察

为研究纤毛虫休眠状态下细胞的分化及其胞器的特征,本文以透射电镜术显示,魏氏拟尾柱虫（Ｐａｒａｕｒｏｓｔｙｌａｗｅｉｓｓｅｉ）休眠包囊中,颗粒层壁内有小泡,表膜位置偶见小泡样结构,大部分线粒体以多个相互聚集在一起,自噬泡将线粒体等胞器包裹在内经历消化过程,细胞内膜系统十分发达。作者推测,颗粒层及表厝小泡可能是休眠细胞经由表膜进行物质交换的结构,自噬泡消化现象可能是细胞中物质和能量来源的主要途径。     

Genetic association between the apolipoprotein E (ApoE) gene alleles and various forms of Alzheimer's disease]

Allele epsilon 4 of the apolipoprotein E (APOE) gene is associated with higher risk of Alzheimer's disease (AD) in many, though not all, ethnic groups. The APOE allele and genotype frequency distributions were studied in 207 AD patients without cerebrovascular disorders, 62 AD patients with cerebrovascular disorders (combined AD), and 206 control individuals (ethnic Russians from the Russian population). The frequency of allele epsilon 4 in patients with early-onset and late-onset AD was three times higher than in control individuals (p < 0.000001). Compared with control people, patients with cerebrovascular disorders displayed a twofold higher frequency of allele epsilon 4; the difference between the two groups was significant (p = 0.0019). Relative risk of AD in carriers of allele epsilon 4 was five times higher than in carriers of alleles epsilon 2 and epsilon 3 (p < 0.000001). Allele epsilon 2 had a protective effect with respect to AD onset until 65 years of age (p = 0.015). Thus, APOE allele epsilon 4 proved to be a universal factor of early-onset, late-onset, and combined AD in ethnic Russians from Russia.     

FINE STRUCTURE OF TRABECULA IN THE ELYTRA OF ALLOMYRINA DICHOTOMA (LINNE) AND PROSOPOCOILUS INCLINATUS (MOTSCHULSKY) (COLEOPTERA: SCARABAEEDAE)

Abstract To obtain new ideas on optimal composite material structure, the fine structures of the trabeculae of the elytra of Allomyrina dichotoma (Iinné) and Prosopocoilus inclinatus (Motschulsky) were investigated using scanning electron microscope. The shape and size of trabeculae, which form the internal bridges between the upper and lower surfaces of the elytra, depend on the species of beetles. Complex surface structures (stripes or bandings) were found in those of A. dichotoma , but less in P. inclinatus . The trabeculae consisted of three parts: the surface part, the cylindrical layer and the central part. The surface and the central part were mainly protein substances which could be dissolved by KOH. The cylindrical layer had many chitin fibers with different orientation, and they were embedded in a protein matrix, and were connected to endocuticle chitin fibers on the upper and lower parts of the lamination.     

抗体酶设计新思想——疏水腔修饰法

提出一种新的抗体酶设计思想———疏水腔修饰法 ,并根据这一思想合成出谷胱甘肽 (GSH)的类似物S 二硝基苯取代的谷胱甘肽二丁酯 (GSH S DNPButyles ter)作为半抗原Hapten 3;将该半抗原连到载体蛋白上进行免疫 ,利用单克隆抗体制备技术得到抗体 1C8,通过 2步化学修饰方法 ,将谷胱甘肽过氧化物酶的催化基团硒代半胱氨酸 (Sec)引入到抗体 1C8可变区中 ,得到转换值即催化中心活力 (kcat)为天然兔肝谷胱甘肽过氧化物酶 1 7倍的抗体酶Se 1C8,是曾经报道抗体酶Se 4A4,Se 4G3的 40倍和 5 3倍 ,是目前与天然酶相比催化效率最高的抗体酶 ,这一结果也验证了提出的抗体酶设计思想     

The characteristics of the spindle fiber attachments (SFAs) enriched fraction from mouse nuclei

The characteristics of the particulate mouse centromere enriched fraction from isolated nuclei obtained in our laboratory were investigated by indirect immunofiuorescence, test of the activity of microtubule organizing center(MTOC), SDS-PAGE, and fluorescence in situ hybridization. Most of the particles of the fraction are complexes of DNA and kinetochore proteins and show MTOC activity. The DNA isolated from the fraction can hybridize with DNA in the regions of the primary constrictions of all chromosomes of ascites cells. The kinetochore proteins isolated from the fraction are mainly those with molecular weight of 55 KD and 59 KD. Results suggested that the fraction obtained is a centromere enriched nuclear fraction as indicated in our previous report.     

肾上腺素和去甲肾上腺素对离体大鼠颗粒细胞雌二醇生成的影响

本工作采用离体孵育大鼠颗粒细胞的方法,观察了肾上腺素和去甲上腺素对颗粒细胞雌二醇生成的影响,为进一步探讨其作用机制,实验还观察了β－肾上腺素能受体阻断剂心得安,外源性ｃＡＭＰ和腺苷酸环化酶激动剂对肾上腺素和去甲肾上腺素诱导颗粒细胞雌二醇生成的影响,结果发现,肾上腺素和去甲肾上腺素可明显促进离体大鼠颗粒细胞雌二醇的生成,此作用可被心得安阻断,外源性ｃＡＭＰ和Ｆｏｒｓｋｏｌｉｎ可促进肾上腺素和去甲肾上