磷脂酶C-γ2与信号转导

细胞间信息传递及细胞外信号对靶细胞的调控,多年来一直是生物学和医学界研究的焦点。随着Ｃａ２＋和二酰基甘油（ｄｉａｃｙｌｇｌｙ－ｃｅｒｏｌ,ＤＡＧ）第二信使地位的确定,对磷脂酶Ｃ（ＰＬＣ）的研究引起了人们的关注。ＰＬＣ可水解磷脂酰肌醇４,５－二磷酸（ｐｈｏｓ－ｐｈａｔｉｄｙｌｉｎｏｓｉｔｏｌ４,５－ｂｉｓｐｈｏｓｐｈａｔｅ,ＰＩＰ２）产生肌醇１,４,５－三磷酸（ｉｎｏｓｉｔｏｌ１,４,５－ｔｒｉｐｈｏｓｐｈａｔｅ,ＩＰ３）和ＤＡＧ。ＩＰ３可导致细胞内储存Ｃａ２＋的释放。因此,ＰＬＣ处于Ｃａ２＋和Ｄ…     

磷脂酰肌醇二磷酸

磷脂酰肌醇 4,5二磷酸 (ｐｈｏｓ ｐｈａｔｉｄｙｌｉｎｏｓｉｔｏｌ(4,5 ) ｂｉｓｐｈｏｓｐｈａｔｅ,ＰＩＰ2 )仅占膜磷脂的不到 1 % ,功能却非常复杂。这种低丰度的多磷酸肌醇脂 (ｐｏｌｙｐｈｏｓｐｈｏ ｉｎｏｓｉｔｉｄｅｓ)可被激素或细胞因子受体介导活化的磷酸脂酶Ｃ(ｐｈｏｓｐｈｏｌｉｐａｓｅＣ ,ＰＬＣ)水解为第二信使分子肌醇三磷酸 (ＩＰ3)和二酰基甘油 (ＤＡＧ)参与信号传递。最近的研究表明细胞表面 ,即质膜 ,是ＰＩＰ2 功能表现的主要场所 ,参与了细胞膜上许多重要生理过程 ,如膜转运、膜与细胞骨架之间的相互作用及其与…     

植物信号传导中的磷脂酶

20世纪 80年代早期人们意识到构成细胞膜的磷脂不只是一道将细胞物质与外界隔开的屏障,而且是细胞对外界环境刺激作出应答的物质基础。磷脂酰肌醇（ｐｈｏｓｐｈｏｔｉｄｙｌｉｎｏｓｉｔｏｌ,ＰＩ）不但是构成细胞膜的重要组分（约占细胞膜组分的 10 %）,在细胞内外环境信号的传递方面也起着重要的作用［1］。磷脂酶（ｐｈｏｓｐｈｏｌｉｐａｓｅ）水解磷脂后产生的三磷酸肌醇 （ｉｎｏｓ ｉｔｏｌｔｒｉｓｐｈｏｓｐｈａｔｅ,ＩＰ3 ）／二酰基甘油（ｄｉａｃｙｌｇｌｙｃｅｒｏｌ,ＤＡＧ）、磷脂酸（ｐｈｏｓｐｈａｔｉｄｉｃａｃｉ…     

5-HT和NA增强大鼠骶髓后连合核神经元甘氨酸门控Cl~-通道电流由蛋白激酶介导

用制霉菌素穿孔膜片钳方法研究５－ＨＴ和ＮＡ对急性分离的大鼠骶髓后连合核神经元甘氨酸门控氯离子通道电流（ＩＧｌｙ）的调控作用及其胞内机制。发现：（１）５－ＨＴ激活与非胰岛激活蛋白（ＩＡＰ）敏感型Ｇ蛋白偶联的５－ＨＴ２受体亚型,激活磷脂酶Ｃ（ＰＬＣ）,增加甘油二酯（ＤＡＧ）的生成。ＤＡＧ增强不依赖Ｃａ２＋的新型ＰＫＣ（ｎＰＫＣ）的活性,从而增强ＩＧｌｙ;（２）ＮＡ激活与ＩＡＰ敏感型Ｇ蛋白偶联的α２受体,抑制腺苷酸环化酶（ＡＣ）,减少ｃＡＭＰ的生成,使ＰＫＡ活性降低,从而增强ＩＧｌｙ。     

C5a受体的作用位点及信号传导

Ｃ５ａＲ（ＣＤ８８）属Ｇ蛋白偶联／ＳＴＲ超家族超成员,它至少具两个配体结合位蹼：一个位于Ｎ末端,另一个可能为第二细胞外环上的Ｇｌｕ＾１９９。Ｃ末端和第三胞浆内环与Ｇ蛋白偶联。与Ｃ５ａＲ偶联的Ｇ蛋白有Ｇｉα２、Ｇｉα３、Ｇ１６和Ｇｚ,已知涉及的信号传导通路为ＰＩ－ＰＬＣ、Ｒａｓ／Ｒａｆ／ＭＡＰＫ、ｃＡＭＰ。Ｃ５ａＲ分子及基因结构已阐明,各功能位点,信号传导还有待深入研究。     

PAF对肺内小动脉平滑肌细胞TXA_2，PGI_2乃Ca~（2＋）－ATPase的影响

本工作采用分离培养家兔肺内小动脉平滑肌细胞（ＰＡＳＭＣｓ），观察了外源性血小板活化因子（ｐｌａｔｅｌｅｔａｃｔｉｖａｔｉｎｇｆａｃｔｏｒ，ＰＡＦ）、ＢＮ５２０２１（ＰＡＦ受体拮抗剂）、吲哚美辛、维拉帕米对ＰＡＳＭＣｓ产生血栓素Ａ_２（ＴｘＡ_２）、前列环素（ＰＧＩ_２）及对细胞膜Ｃａ~（２＋）－ＡＴＰａｓｅ活力的影响。结果表明：（１）基础状态下ＰＡＳＭＣｓ存在花生四烯酸（ＡＡ）代谢。（２）外源性ＰＡＦ通过受体后途径激活环加氧酶促进ＡＡ代谢致ＴＸＡ_２及ＰＧＩ－２增加，ＴＸＡ_２／ＰＧＩ_２比值无明显变化。（３）外源性ＰＡＦ能直接抑制Ｃａ~（２＋）－ＡＴＰａｓｅ活力。（４）维拉帕米可逆转ＰＡＦ抑制ＰＡＳＭＣｓ膜Ｃａ~（２＋）－ＡＴＰａｓｅ活力的效应。     

提高外淋巴钙浓度对耳蜗电位的影响

本实验以人工外淋巴灌流方式,提高豚鼠耳蜗外淋巴液钙离子浓度（［Ｃａ２＋］ＰＬ）,观察蜗内直流电位（ＥＰ）和耳蜗电图（ＥＣｏｃｈＧ）的变化,ＥＣｏｃｈＧ包括听神经复合动作电位（ＣＡＰ）、耳蜗微音电位（ＣＭ）。结果可见：高钙灌流明显抑制ＣＡＰ幅值,延长同一声强下（９０ｄＢＳＰＬ）Ｎ１－峰潜伏期,但不改变ＣＭ的幅值及总和ＥＰ（Ｇ－ＥＰ）。高钙灌流降低了ＥＰ对噪声的给－撤声反应（ＥＰ－ＯＮ,ＥＰ－ＯＦＦ）和缺氧所得到的最大负ＥＰ（Ｎ－ＥＰ）绝对值。本文分析了外淋巴高钙影响耳蜗电位的可能机制。     

碱性磷酸酶底物的研究——兼介绍一种新底物: 萘酚AS-OL磷酸

本文研究了免疫组织化学方法中碱性磷酸酶（ＡＰ）的显色系统。本文以人扁桃体的石蜡切片为材料,以ＣＤ２０为标记,二抗为生物素标记的兔抗鼠抗体,选择了５种萘酚磷酸（ｎａｐｈｔｈｏｌＡＳ－ＯＬｐｈｏｓｐｈａｔｅ,ｎａｐｈｔｈｏｌＡＳ－ＧＲｐｈｏｓｐｈａｔｅ,ｎａｐｈｔｈｏｌＡＳ－ＴＲｐｈｏｓｐｈａｔｅ,ｎａｐｈｔｈｏｌＡＳ－ＭＸｐｈｏｓｐｈａｔｅ和ｎａｐｈｔｈｏｌＡＳ－ＢＩｐｈｏｓｐｈａｔｅ）与９种重氮化合物（ｆａｓｔｒｅｄＴＲｓａｌｔ,ｆａｓｔｂｌａｃｋＫｓａｌｔ,ｆａｓｔｂｌｕｅＢＢｓａｌｔ,ｆａｓｔｂｒｏｗｎＲＲｓａｌｔ,ｆａｓｔｓｃａｒｌｅｔＲｓａｌｔ,ｆａｓｔｂｌｕｅｓａｌｔＢＮ,ｆａｓｔｂｌｕｅＢ,ｆａｓｔｄａｒｋｂｌｕｅＲｓａｌｔ,ｆａｓｔｒｅｄｖｉｏｌｅｔＬＢｓａｌｔ）以及新品红为ＡＰ显色底物,相互配伍,根据形成的一系列显色反应,比较研究了不同的底物对。研究结果表明：在５种萘酚磷酸中,ｎａｐｈｔｈｏｌＡＳ－ＯＬｐｈｏｓｐｈａｔｅ具有良好的显色敏感性,当一抗为１∶１０００时,与常用ｎａｐｈｔｈｏｌＡＳ－ＢＩｐｈｏｓｐｈａｔｅ一样,具有较强的显色反应;该底物还具较好的配伍性,能与新品红和ＦａｓｔＢｌｕｅ     

5—HT和NA增强大鼠骶髓后连合核神经元甘氨酸门控Cl^—通道电流由蛋白激...

用制霉菌素穿孔膜片钳方法研究５－ＨＴ和ＮＡ对急性分离的大鼠骶髓后连合核神经元甘氨酸门控氯离子通道电流（ＩＧｌｙ）的调控作用及其胞内机制。发现：（１）５－ＨＴ激活与非胰岛激活蛋白（ＩＡＰ）敏感型Ｇ蛋白偶联的５－ＨＴ２受体亚型,激活磷脂酶Ｃ（ＰＬＣ）,增加甘油二酯（ＤＡＧ）的生成。ＤＡＧ增强不依赖Ｃａ＾２＋的新型ＰＫＣ（ｎＰＫＣ）的活性,从而增强ＩＧｌｙ;（２）ＮＡ激活与ＩＡＰ敏感型Ｇ蛋白偶联的α２受     

缺血-再灌注时大鼠心脏Gi蛋白α亚基的变化

本工作研究了心肌缺血－再灌注时,受体－腺苷酸环化酶细胞膜信号转导系统中Ｇ蛋白含量及功能的变化。采用免疫印迹法和放射免疫法分别测定大鼠心脏Ｇｉα２,Ｇｉα３和Ｇｓα的含量及腺苷酸环化酶的活性。结果显示缺血－再灌注时心功能明显损伤;心脏Ｇｓα无明显变化;心肌细胞膜Ｃｉα２和Ｇｉα３含量分别升高３７．４％（Ｐ〈０．０１）和４２．４％（Ｐ〈０．０１）;胞浆内Ｇｉα２和Ｇｉα３含量无明显变化;缺血心肌腺苷酸     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.