杜氏盐藻（Dunaliellasalina）盐适应相关蛋白

观察不同盐浓度培养中生长的杜氏盐藻可溶性蛋白ＳＤＳ－ＰＡＧＥ图谱,发现高盐与低盐相比,其５１ＫＤ和６３ＫＤ蛋白含量高,而２３ＫＤ的蛋白含量则代。高渗骤变后,５１ＫＤ蛋白的含量减少,而２ＫＤ蛋白的含量增加两倍或两倍以上,骤变２３ｈ后含量增加已非常明显。     

耐盐突变体小麦后代耐盐稳定性分析研究

以卫星搭载小麦种子为原始材料,利用其幼穗、幼胚诱导的愈伤组织进行耐盐突变体的筛选,对耐盐愈伤组织再生植株后代进行耐盐稳定性生理生化特性分析。结果表明：(1)耐盐系后代在土壤高盐浓度条件下,游离脯氨酸含量稳定增加,且高于对照系;(2)耐盐系再生植株后代保持较高的K^ ／Na^ 比;(3)与对照相比,种子醇溶蛋白电泳带谱中的b2,b3,b5,b7带为耐盐系所特有,b8带消失;(4)耐盐系再生植株后代可溶蛋白电泳带为26条,而对照系为23条蛋白带。其中98kD、75kD、52kD、49kD和32kD为耐盐系的特有蛋白带。而38kD和35kD蛋白带为对照系所特有。     

盐激条件下快生大豆根瘤菌的渗透调节

快生大豆根瘤菌(Rhizobium fredii)RTl9在基本培养基中能耐800 mmol/L。NaCl。该菌株在对数生长后期,突然加入高浓度NaCl,使其培养液中的NaCl最终浓度为1000mmol/L。5分钟后,细胞内谷氨酸的含量便急剧增加,而且脯氨酸也大量积累。50分钟后,它们的含量分别达到未受盐激的(对照)4倍和3.8倍。在盐激条件下,RTl9的谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)的活性比对照明显提高。其中GS活性的提高主要是由GSⅡ引起的,GSI变化不大。将这两种酶直接暴露于1000mmol/LNaCl,50分钟后,酶活性降至原来的70％,并未完全失活。聚丙烯酰胺凝胶双向电泳的分析表明,若干蛋白质在盐激后消失,而且发现两种蛋白质是新合成的,其分子量和等电点(MW/pI)分别为110 kD/4.3和76 kD/6.5。     

苜蓿愈伤组织中的盐胁迫蛋白

0.5％NaCl抑制愈伤组织生长,处理后期(第21天和28天检测)24kD蛋白含量明显增加。1.0％,2.0％和3.0％NaCl处理的愈伤组织不生长,未检出24kD蛋白增加,但36～42kD蛋白大量增加,并且有随处理的盐浓度增高而增加的趋势。 在1.0％NaCl适应愈伤组织(简称S-1)中24kD蛋白含量明显增加,而36～42 kD蛋白含量下降到对照水平。~(35)S-Met体内标记表明,增加的24kD蛋白是新合成的。S-1回到无盐5代后,仍保持提高的耐盐性和24kD蛋白含量。24kD蛋白含量的增加不受甘露醇胁迫的诱导。初步离心分离的细胞亚组分表明,24kD蛋白主要位于胞质和细胞器膜。在烟草S-1细胞中也发现24kD蛋白含量增加。     

盐适应和非盐适应烟草愈伤组织蛋白质组分变化

通过在培养基中逐代增加氯化钠浓度方法获得的适应0.5％到1.0％NaCl的盐适应细胞系,与非盐适应细胞系的蛋白质电泳图谱相比,其蛋白质SDS-PAGE图谱中出现了26kD蛋白质,但量不多;此外,40.3和16.5kD蛋白质量增加,其中16.5kD蛋白质增加显著;而33.8和18kD蛋白质则减少。上述16.5,26和40.3kD蛋白质的诱导产生或含量的增加和细胞在盐环境中表现出的适应性相伴随发生,表明这3种蛋白质可能与抗盐性有关。     

钙离子对盐胁迫小麦幼苗氮代谢的影响

为探讨增强小麦抗盐能力的调控途径,以普通小麦豫麦34为材料,研究了Ca2+对盐胁迫下小麦幼苗氮代谢及生长的影响.采用全营养液培养小麦幼苗至第一片叶完全展开,更换无钙营养液,并开始不同处理.处理分别为低盐胁迫(150 mmol · L-1 NaCl)、低盐胁迫+4 mmol · L-1 Ca2+、高盐胁迫(300 mmol · L-1 NaCl)、高盐胁迫+4mmol · L-1 Ca2+,以无NaCl胁迫的小麦为对照.5 d后取样,测定了氮同化酶活性、代谢物含量、积累量及幼苗生长状况.结果表明,Ca2+明显缓解了低盐胁迫对小麦幼苗的生长抑制,表现在鲜重、叶绿素及可溶性蛋白含量的增加,而对高盐胁迫下小麦幼苗的生长无明显改善效果;Ca2+改善了低盐胁迫下小麦幼苗的氮营养状况,表现在氮积累量的增加,这一效应主要是通过硝酸还原酶(NR)、谷氨酰胺合成酶(GS)以及异柠檬酸脱氢酶(NADP-ICDH)活性的增强而实现的.Ca2+未能改善高盐胁迫下小麦幼苗氮营养状况的主要限制因子在于NADP-ICDH活性未明显增加.     

苜蓿盐适应愈伤组织中蛋白质性质和组分的变化

通过一步筛选获得1.0％NaCl适应愈伤组织。在盐适应愈伤组织中水溶性蛋白和稀碱提取蛋白含量增加,而脂溶性蛋白含量没有明显变化。盐适应愈伤组织水溶性蛋白热稳定性下降;总蛋白抗脱水能力增强。盐适应愈伤组织水溶性蛋白在K~ 存在时,262nm吸收峰增高。盐适应愈伤组织蛋白氨基酸组成发生变化,其中最为明显的是Tyr摩尔百分数增加。Lys摩尔百分数减少。 盐适应愈伤组织中24kD蛋白含量明显增加。应用IEF-,NEPHGE-和native-PAGE-SDS-PAGE三种双向电泳方法同时证明在盐适应愈伤组织蛋白组分与非适应愈伤组织有明显差别。     

外源亚精胺对盐胁迫下黄瓜幼苗生长和可溶性蛋白表达的影响

采用营养液水培方法,研究了叶面喷施亚精胺(Spd)对黄瓜幼苗生长和可溶性蛋白的影响.结果表明,外源Spd可使盐胁迫黄瓜幼苗株高、茎粗、叶面积、根长和根表面积显著增加,可溶性蛋白含量明显提高,部分可溶性蛋白的表达量减弱;而对正常生长条件下黄瓜幼苗各生长指标无明显影响,但显著提高了根系中可溶性蛋白的含量.随着Spd处理时间的延续,盐胁迫幼苗至少有7种分子量分别约为67、61.5、50、47、43、29和16 kD的可溶性蛋白表达量发生明显变化,尤其使61.5、47和43 kD蛋白表达量明显减弱,50 kD蛋白甚至消失,这4种蛋白可能与外源Spd缓解黄瓜幼苗盐胁迫伤害效应关系密切.     

药用红花幼苗对盐胁迫的生理响应机制

以红花为材料,研究了不同浓度NaCl(0、50、100和150 mmol·L-1)胁迫对红花幼苗叶片中的可溶性糖(SS)、可溶性蛋白(SP)及抗氧化酶系(T-AOC、SOD、CAT)的影响。结果表明:盐分对红花幼苗生长的抑制作用随NaCl浓度增加而加剧,且对地上部分的抑制作用大于根部。胁迫初期(10 d),各处理红花幼苗中的T-AOC的活性没有明显变化;但高盐胁迫显著提高了CAT的活性。与对照相比,盐胁迫明显提高了红花中的SS、SP的含量及SOD的活性,但各盐处理之间没有明显差异。胁迫中期(20 d),各处理间SOD的活性无明显变化;SS的含量随盐浓度的增加而明显增加,且处理间差异显著;SP的含量和CAT、T-AOC的活性与对照相比均有所增加。盐胁迫后期(30 d),SP和SS的含量在叶片中有积累的趋势,但T-AOC和SOD却相反,其活性较对照处理均有所下降,而盐处理的CAT的活性较对照处理无明显差异。因此,供试红花幼苗在盐胁迫初期主要是通过合成渗透调节物质和活性氧清除机制共同作用来抵御盐分胁迫,随着胁迫时间的延长则主要通过合成渗透调节物质来抵御盐害,其中可溶性糖对盐浓度的响应起到关键作用。     

杜氏盐藻和亚心形扁藻在不同接种密度和氮浓度下的细胞群体生长

在氮浓度为1.4、14、和140 mg·L^-1下,对杜氏盐藻(Dunaliella salina)和亚心形扁藻(Platymonas subcordiformis)进行细胞接种比例为10:0、7:3、5:5、3:7和0:10的培养试验,研究不同海洋经济微藻种间混合培养的细胞群体生长效应。结果表明,杜氏盐藻与亚心形扁藻细胞群体的生长随着氮浓度的增加而提高;两种藻在氮浓度分别为14和140mg·L^-1时混合培养的细胞群体生长明显优于单独培养。中、高氮下杜氏盐藻与亚心形扁藻以7:3的接种比例混合时,微藻的细胞群体生物量和胞内物质含量相比单独培养和其他比例均有显著提高,如叶绿素a含量比单独培养分别提高1.17倍和7.77倍;蛋白质含量比单独培养分别提高19.1%和195.3%等。而低氮浓度下,藻的生长受到氮浓度的限制。     

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.