高光胁迫对水稻籼粳亚种两个品种色素蛋白复合体的影响

以耐光抑制的水稻(Oryza sativa L.)粳亚种品种"武育粳"和对光抑制敏感的籼亚种品种"汕优63"的剑叶为材料,比较研究了高光胁迫对水稻两个亚种光合系统的影响.结果表明,高光胁迫影响激发能在两个光系统之间的分配,抑制激发能向PSⅡ传递.在籼稻中激发峰和发射峰以及相关比值在受到高光胁迫后下降的幅度均比在粳稻中显著.与粳稻相比,高光胁迫几乎使籼稻的PSⅡ捕光色素蛋白复合体的三聚体解体,使其PSⅡ捕光色素蛋白复合体的二聚体、PSⅡ内周天线色素蛋白复合体、PSⅠ捕光色素蛋白复合体以及PSⅠ反应中心叶绿素a蛋白复合体的含量明显降低.高光胁迫导致水稻两亚种的PSⅡ捕光色素蛋白复合物单体含量的增加.类囊体膜多肽分析表明,高光胁迫使属于PSⅡ捕光色素蛋白复合体的27、25 kD蛋白和PSⅠ捕光色素蛋白复合体的21 kD蛋白含量在水稻两亚种中都降低,其中以25 kD蛋白含量降幅最大.在籼稻中高光胁迫使属于PSⅡ内周天线色素蛋白复合体的43 kD和47kD蛋白以及外周23kD蛋白含量明显降低而在粳稻中则影响较小.     

莲子在光下萌发过程中叶绿体色素蛋白质复合体及光化活性的变化

实验研究了莲种子（ＮｅｌｕｍｂｏｎｕｃｉｆｅｒａＧａｅｒｔｎ．）在光下萌发过程中叶绿体色素蛋白复合体、多肽组成以及ＰＳⅡ光化活性的变化。结果表明,萌发到第６天的莲胚芽叶绿体,在ＳＤＳＰＡＧＥ凝胶柱中只分出两条色素带,分别为捕光叶绿素蛋白复合体（ＬＨＣⅡ）和自由色素（ＦＰ）。萌发到第８天的莲叶绿体可分出ＣＰⅠ,ＬＨＣⅡ１、ＬＨＣⅡ和ＦＰ。仍未检测到ＰＳⅡ反应中心复合物。多肽分析表明：未萌发和萌发到第２天的叶绿体中３０ｋＤ多肽的含量显著,尽管２７ｋＤ多肽在未见光时已开始合成,但其含量很少。随着照光时间增长,３０ｋＤ多肽含量逐渐减少,２７ｋＤ多肽的含量逐渐增多,到第１２天时超过３０ｋＤ多肽的含量。电子传递速率和室温荧光诱导动力学的测定表明：ＰＳⅡ光化活性在莲子萌发到第７天时才开始出现,并随萌发时间增加而升高,与此同时Ｃｈｌａ／ｂ比值由低到高达到正常值。莲子在光下萌发过程中其叶绿体膜成分及膜功能的变化与它的超微结构的变化相符合。结果再次证明,莲胚芽叶绿体在光下的发育具有与其它高等植物所不同的独特途径,这为莲在被子植物系统发育中占有独特地位的看法提供了依据。     

高光胁迫对水稻籼粳亚种两个品种色素蛋白复合体的影响

以耐光抑制的水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）粳亚种品种“武育粳”和对光抑制敏感的灿亚种品种“汕优６３”的剑叶为材料,比较研究了高光胁迫对水稻两个亚种光合系统的影响。结果表明,高光胁迫影响激发能在两个光系统之间的分配,抑制激发能向ＰＳⅡ传递。在籼稻中激发峰和发射峰以及相关比值在受到高光胁迫后下降的幅度均比在粳稻中显著。与粳稻相比,高光胁迫几乎使籼稻的ＰＳⅡ捕光色素蛋白复合体的三聚体解体,使其Ｐ     

紫细菌光合机构及光合作用基因的表达调控

紫细菌是研究细菌光合作用的重要生物.介绍了紫细菌光合机构捕光色素蛋白复合体Ⅰ(light-harvestingⅠ)、捕光色素蛋白复合体Ⅱ(1ight-harvesting Ⅱ)和光化学反应中心(reaction center)的结构,并探讨了其光合作用基因的转录调控机制,重点阐述了PpsR/AppA系统对紫细菌光合作用基因的转录调控.     

低温下强光胁迫对小麦叶片光系统I结构与功能的影响

探讨了低下强光胁迫对小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）扬麦５号苗期叶片（第三叶）类囊本膜上ＰＳⅠ－２００颗粒光化学特性和组分的影响。光胁迫条件下,ＰＳⅠ－２００颗粒的电子传递活性受到抑制,４℃条件下光胁迫的抑制程度低于２５℃下的抑制,２５℃条件下,光胁迫导致ＰＳⅠ－２００颗粒还原侧１９ｋＤ及ＬＨＣⅠ等多肽降解;而４℃条件下,１９ｋＤ保持稳定,但ＬＨＣⅠ等多肽在光胁迫处理过程中却发生降     

茶叶片阶段性返白过程中色素蛋白复合体的变化

用ＳＤＳ－ＰＡＧＥ盘状电泳从温敏型阶段性返白的安吉白茶完全复绿叶中分离出２条叶绿素ａ蛋白复合物（ＣＰⅠ）、２条叶绿素ａ／ｂ捕光蛋白复合物（ＣＰⅡ：ＬＨＣＰ１、ＬＨＣＰ２）和１条游离色素带,而全白期叶片中则未发现ＣＰⅠ和ＣＰⅡ,但有很少量ＣＰⅡ的脱辅基蛋白和游离色素。此类叶片开始得绿时,ＣＰⅠ、ＬＨＣＰ１和ＬＨＣＰ２同时出现,但寡聚形式（ＣＰⅠａ）的恢复稍迟些,各种色素蛋白复合体的含量均随绿逐步上升     

紫细菌光合机构及光合作用基因的表达调控

紫细菌是研究细菌光合作用的重要生物。介绍了紫细菌光合机构捕光色素蛋白复合体Ⅰ(light-harvesting I)、捕光色素蛋白复合体Ⅱ(light-harvesting II)和光化学反应中心(reaction center)的结构, 并探讨了其光合作用基因的转录调控机制, 重点阐述了PpsR/AppA系统对紫细菌光合作用基因的转录调控。     

水分胁迫对小麦捕光色素蛋白复合物的影响

棉农４号春小麦幼苗（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｕｖｕｍ Ｌ．ｅｖ ．Ｍｉａｎｎｏｎｇ Ｎｏ．４）经一０．５ＭＰａ ＰＥＧ溶液渗透胁迫２４、４８和７２ｈ,使叶片分别受到轻蔗、中度和重度的水分胁迫。在渐进水分腔迫条件下,叶绿体类囊体膜中光系统Ⅱ捕光色素蛋白得合物（ＬＣＨ Ⅱ）的各组分含量发生了不同变化。对类囊体纱蛋白复合物进行的温和电泳结果显示,在轻度水分胁迫（２４ｈ）时,明轻度水分胁迫对其有诱导作     

不同品种花生种子蛋白质的电泳分析

对中国花生（ＡｒａｃｈｉｓｈｙｐｏｇａｅａＬ．）５种不同类型的４６个栽培品种的种子蛋白质进行电泳分析。ＳＤＳＰＡＧＥ和ＩＥＦＳＤＳＰＡＧＥ（双向电泳）的结果显示,不同品种的花生种子蛋白多肽组成存在４种类型。与初步纯化的花生球蛋白及伴花生球蛋白的ＳＤＳＰＡＧＥ结果比较,花生种子蛋白组成的主要差异在于花生球蛋白亚基组成的不同,其中类型Ⅰ花生球蛋白主要含有４１ｋＤ、３８５ｋＤ和２个１８ｋＤ亚基,类型Ⅱ主要含４１ｋＤ、３８５ｋＤ、３７５ｋＤ和３个１８ｋＤ亚基,类型Ⅲ主要含４１ｋＤ、３８．５ｋＤ、３６．５ｋＤ和３个１８ｋＤ亚基,类型Ⅳ主要含４１ｋＤ、３８．５ｋＤ、３７５ｋＤ、３６．５ｋＤ和３个１８ｋＤ亚基。不同品种的伴花生球蛋白多肽组成基本一致。对不同类型８个品种种子蛋白的氨基酸组成进行测定,发现类型Ⅰ的含硫氨基酸含量较高。     

小麦返白系返白阶段叶片蛋白质变化与叶绿素含量的关系

小麦返白系春天现出白色心叶,白叶中有脱辅基蛋白存在,但含量很低。白叶复绿时色素条带中ＣＰⅡ出现先于ＣＰＩ,叶绿素含量的增加与色素蛋白的出现呈正相关,同时影响蛋白含量,但２１、２５ｋＤ蛋白即使在全白叶中也较高水平,白叶中ＲｕｂｉｓｃｏＬＳ含量极低,而ＳＳ仅略有降低,复绿初期蛋白质合成速率随叶绿素含量增而显著提高,ＬＳ也迅速增加。     

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.