杂种稻Le/Qi及其亲本光合特性的比较研究

研究比较了杂种稻Ｌｅ／Ｑｉ及其亲本Ｌｅｍｏｎｔ、七桂早在光合特性上的差异。结果表明,杂种稻Ｌｅ／Ｑｉ有较高的光系统ＩＩ活性、光系统ＩＩ原初光能转化效率和光合电子传递速率;色素测定结果显示,杂种稻Ｌｅ／Ｑｉ叶片中的类胡萝卜素含量可随光强增加而大幅度提高;叶绿体可溶性蛋白分析同样显示出Ｌｅ／Ｑｉ与双亲的差异,这些都是杂种稻Ｌｅ／Ｑｉ具有较高光合生产力的生理基础。     

两个不同基因型小麦光抑制特性的比较

比较了两个不同基因型小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）“京４１１”和“小偃５４”的原初光能转化效率、荧光猝灭参数和光合色素对强光胁迫的响应。在正常生长条件下“京４１１”的光合色素含量高于“小偃５４”;但在高光强下“京４１１”出现明显的光抑制,而“小偃５４”对高光强的适应上优于“京４１１”。“小偃５４”适应高光强的原因是它在高光强下能大幅度地提高叶黄素循环的调控因子抗坏血酸的浓度及紫黄     

光强度对小麦幼苗光合特性的影响

研究了在两种不同光强下水培5－7天的小麦（Triticum aestivum)“农大139”幼苗的光合特性,观察到生长期间的不同光强度对麦幼苗的光合膜一些成分和光合特性有明显影响,单位叶面积或单位鲜重中的Chl含量,Chl a/b比值,单位鲜重中的Car含量,以及光合膜中CPIa和CPI的含量,在低光强（2×10^3lx)下生长的幼苗都低,而光合膜中的LHCP的含量则高于在高光强（2×10^4lx)下生长的小麦幼苗,荧光诱导动力学测定结果表明,在高光强下生长的小麦其光合单位较小,而PSII活性和PSII原初光能转化效率都较高,同时,它们的叶绿体的PSII,PSI和全链电子传递速率也较高。     

水稻耐光氧化和耐荫特性的生理基础

用简易、有效的人工光氧化和遮荫技术对３０个水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）种质进行筛选,鉴定出既耐光氧化又耐荫、耐光氧化不耐荫、耐荫不耐光氧化、既不耐荫又不耐光氧化等４种品种类型,并用既耐光氧化又耐荫的品种“武育粳３号”和对光氧化和遮荫均敏感的品种“香籼”进行光合特性研究。结果表明：在遮荫条件下,与对光氧化和遮荫敏感的品种“香籼”比较,“武育粳３号”的ＰＳⅡ活性差异不大,ＲｕＢｉｓＣＯ活性降     

大豆叶片CO2补偿点和光呼吸的关系

为了探讨ＣＯ２补偿点（Г）与光呼吸（Ｒｐ）的关系,用ＣＩ－３０１光合敢体分析系统观察了光强等因素对大豆叶片ＣＯ２补偿点的影响。在高于生长光强的强光下,Г和Ｒｐ随着光强的增高而升高,实验表明这可能与强光下发生的无机磷限制有关;经１０ｍｍｏｌ／Ｌ的甘露糖、０．２％ＰＥＧ６０００和１０ｍｍｏｌ／Ｌ的ＤＬ－甘油醛处理后,Г显著上升,前两者使Ｒｐ下降,而后者使Ｒｐ都降低。并且,衰老叶片的Г比刚完全展开的叶片     

甘薯品种F3282凝集素的提取及性质研究

甘薯品种Ｆ３２８２的浸取液,经硫酸铵分级,甲壳素层析后,再经分子筛过滤,获得在ＰＡＧＥ上呈现单一蛋白质带的甘薯凝集素（Ｉｐｏｍｏｅａ Ｂａｔａｔａｓ Ｌｅｃｔｉｎ,ＩＢＬ）。ＩＢＬ对鸽、兔、人血等红细胞均有凝集作用,其中对鸽血的凝集活性最高,最低凝集浓度为０．０５μｇ／ｍｌ。ＩＢＬ除凝集红细胞外,还可凝集小鼠脾细胞和肿瘤细胞;其对热相当稳定,９０℃加热１０ｍｉｎ,仍有部分活性;ＩＢＬ对酸处理较碱处理稳定,但可被阿拉伯糖或乳糖等解除凝集活性。ＩＢＬ的中性糖含量为５．４％。     

光、暗处理对蚕豆茎内皮层形成的影响 Ⅱ.与栓化作用有关的酶及抗氧化剂的关系

以蚕豆（ＶｉｃｉａｆａｂａＬ．）幼苗为材料,结合不同的光强及黑暗对茎中内皮层形成的影响,对参与栓化作用有关的酶活性及内源抗氧化物质的含量进行了测定,并讨论了光对内皮层形成的调节机制。实验结果表明,高光强抑制茎中内皮层形成,而低光强和黑暗诱导茎中形成内皮层。在低光强和暗中,脂肪氧化酶在内皮层栓化前期活性显著增加,可能与栓化作用的启动有关,而高光强下ＬＯＸ始终处在较低水平。ＰＡＬ活性为光所诱导,与内皮层的栓化没有直接的相关性。在高光强条件下生长的幼苗茎中抗坏血酸和谷胱甘肽含量比低光强和暗中的高。外源施用抗坏血酸,可抑制低光强下茎内皮层的栓化,而对暗中茎内皮层的栓化无影响。推测高强度光对栓化作用的抑制原因可能是高光强下植物体内有高含量的抗氧化物质,并具备更有利的活性氧清除途径,从而抑制了栓化作用的进行     

钙对生长素诱导的玉米胚芽鞘切段延长生长的影响

１０μｇ／ｇ的ＩＡＡ溶液强烈地促进玉米胚芽鞘切段的延长生长和质子分泌,但这两种效应的启动时间有别．Ｃａ２＋在高浓度下（２—５ｍｍｏｌ／Ｌ）强烈抑制ＩＡＡ诱导的延长生长,但在低浓度下（０．５ｍｍｏｌ／Ｌ）则有轻微的促进作用．ＩＡＡ增大质膜相对透性,而Ｃａ２＋则有稳定膜的作用,且适宜的浓度较低（０．５ｍｍｏｌ／Ｌ）．     

不同光强下生长的亚热带树苗的光合-光响应特性的比较

鼎湖山亚热带森林中的优势树种马尾松、荷木、黧蒴和黄果厚壳桂的幼苗,盆栽于100%、40%和16%的自然光下生长1年.利用氧电极离体测定叶片的光合-光响应曲线,结果表明不同树种及同一树种不同生长光强处理之间差异明显.比较最大净光合速率(Amax)、光补偿点、光饱和点、光抑制点及光能利用效率(QUE)等的变化可见,黄果厚壳桂为耐阴植物,对高光强的光合适应潜力为有限,100%的自然光明显抑制其最大同化力;其余3种植物均为喜光植物,其中马尾松的光合作用对遮阴的适应能力较差,而荷木和黧蒴则相对较强.本文还对植物的光合生理特性与其演替状态的联系作了初步探讨.     

人IL-2/IFNα2b融合基因在肝癌细胞中靶向表达

 根据细胞因子之间协同作用的特点,采用重组 Ｄ Ｎ Ａ 技术设计并构建了人 Ｉ Ｌ ２ 与 Ｉ Ｆ Ｎα融合基因,并用肝癌组织特异的 Ａ Ｆ Ｐ增强子／ Ａ Ｌ Ｂ启动子调控融合基因在肝癌细胞中的靶向表达．实验结果表明,克隆的 Ｅ Ａ Ｆ Ｐ Ｐ Ａ Ｌ Ｂ联合转录调控序列能调控细胞因子基因在 Ａ Ｆ Ｐ阳性人肝癌细胞中靶向表达, Ｉ Ｌ ２／ Ｉ Ｆ Ｎα２ｂ 融合基因的表达水平与感染肝癌细胞的 Ａ Ｆ Ｐ表达水平呈正相关性．实验证明表达的融合蛋白具有 Ｉ Ｌ ２ 和 Ｉ Ｆ Ｎ 两种生物学活性的细胞因子．这可能为肝癌基因治疗开辟新途径．     

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.