表观遗传修饰介导的植物胁迫记忆

植物因其固着生长的方式, 已经进化出各类特殊的机制来适应多变的外界环境。为提高自身的存活率, 植物进化出一类胁迫记忆机制, 以适应环境和保护自己。表观遗传修饰不仅能调控植物的正常生长发育, 而且参与植物对各种非生物或生物胁迫的响应。近年的研究表明, 表观遗传修饰在植物胁迫记忆调控中也发挥重要作用。例如, DNA甲基化、组蛋白甲基化及乙酰化等表观遗传修饰参与并维持特定的胁迫记忆。该文主要对表观遗传修饰介导的植物胁迫记忆最新进展进行综述, 并展望未来的重点和热点研究方向。     

B7-2胚胎性癌细胞诱导分化过程中的表型转变

胚胎性癌细胞(简称EC细胞)作为一类肿瘤(畸胎瘤)的干细胞近年受到广泛的重视,从胚胎学、肿瘤学和分子生物学等许多学科领域都应用它作为实验材料,离体诱导分化研究是其中的一个方面。B 7-2 EC细胞是我们从129品系小鼠的自发睾丸畸胎瘤中分离克隆得到的一株多能EC细胞,它在同种同基因小鼠     

Using a non-radioisotopic, quantitative TRAP-based method detecting telomerase activities in human hepatoma cells

INTRODUCTIONTelomerase is a ribonucleoprotein complex that plays a critical role in telomeremaintenance and cellular immortality. Telomerase has been considered as tumordiagnostic marker and potential target for cancer therapyll, 2]. A sensitive, reliableand quantitative assay is of high interest in this field. The development of a very sensitive Telomeric Repeat Amplification Protocol (TRAP) for measuring telomerajseactivity in cell extracts has been proved to be an important tool for…     

从热带海洋细菌培养提取新的消炎大环内酯

Bioory．Med．Chem．Lett．1999年9卷14期2003～2006页报道：美国加利福尼亚大学圣迭戈分校Scripps海洋学研究所海洋生物技术和生物医药中心的科学家,已在从加勒比海褐藻——匍扇网地藻(Lobophora variegata)表面分离出来的热带海洋细菌CNB-837株系培养中,提取了一种新的消炎大环内酯——匍扇藻素A和B。科学家们利用含有1％可溶淀粉、0．4％酵母膏、O．2％胨、75％海水和25％去离子水的A1培养基,在25℃和230转/分搅动下,将这种海洋细菌培养了7天。用小鼠进行了试验表明,局部或腹膜内给予匍扇藻素,可有效地消除小鼠耳部的水肿。匍扇藻素A和B的分子式分别为C61H93N2O19和C61H90N2O21。汪开治     

以胞质分裂阻滞法研究女性年龄与体细胞中 21号染色体分离异常的关系

21三体是人类最常见的先天性疾病,约95%患儿的超数21号染色体来源于母亲,且随母龄增加患儿出生率也随之增加。本文首次运用胞质分裂阻滞法(CB法)对不同年龄女性体细胞进行荧光原位杂交,对其21号染色体的分离情况进行分析。结果表明,随年龄的增加,女性体细胞中21号染色体不分离也随之增加,但21号染色体丢失无年龄效应, 且21号染色体不分离频率远高于其丢失。该结果表明,女性体细胞中21号染色体不分离与生殖细胞同样存在年龄效应。 Abstract　　Trisomy 21 is the most common genetic desease in human. More than 90% is derived from mother. With the advancing of mother's age, the frequency of trisomy 21 is increasing. We detected the relation between chromosome 21 missegregation and age in cytokinesis-blocked female lymphocytes by　in situ　hybridization with chromosome 21 specfic probe. We have found that the age effect also exists in female somatic cells as in gamets.     

水稻抗白叶枯病基因Xa-4的PCR标记研究

根据与水稻抗白叶枯病基因Xa-4紧密连锁的分子标记M55的序列设计引物,通过对国际水稻研究所育成的抗白叶枯病近等基因系和基因累加系的叶片DNA、半粒种子提取物及Xa-4基因的杂合体DNA的PCR特异扩增,初步建立了Xa-4的PCR标记体系。进而用该标记体系对我国籼型杂交水稻常用的亲本材料进行分析,揭示出了Xa-4在这些材料中的分布情况。 Abstract　Based on the sequence of a DNA marker tightly linked to the rice bacterial blight（BB） resistance gene Xa-4, two primers were designated and synthesized to develop a PCR marker for the gene. Specific amplified polymorphism analysis was carried out with these primers on a set of BB resistance isogenic lines and pyramided lines developed by IRRI. Two PCR bands were revealed corresponding to lines with dominant Xa-4 and those with the recessive allele, respectively, regardless the lines pyramided with other resistance genes. A hybrid with heterozygous Xa-4 produced both of the two allele PCR pattern. Then, the PCR marker was used to survey a range of hybrid rice germplasm. The results of the germplasm survey will be useful in hybrid rice breeding programs aimed at exploiting Xa-4.     

Persistence and Periodic Solution for Diffusive Preypredator System with Functional Response

1IntroductionThesurvivalofspeciesisoneofthemostinterestingqllestionsinmathematicalbiology.Persistenceisanimportantconcepttodealwiththisproblem.Recently,manyauthorsfindthatthediffusionprocessinecologicalsystemplaysanimportantrole.Therearemanyliteraturestoinvestigatethedynamicswithdiffusionprocess,butfewerliteraturetoinvestigatethedynamicswithbothdiffusionprocessandfunctionalresponse.Inthispaper,theauthorswillbedevotetostudythethreespeciesdiffosiveprey-predatorsystemwithfunctionalresponseasfoll…     

Gene Diversity, Gene Differentiation Coefficients of Parent Populations and Prediction of Their F_1 Heterosis

1IntroductionThepredictionofheterosisisveryimportantinbreeding.Atearlystage,scientistspaidgreatattentiontopredictheterosisbyusinggeneticdistancebasedonqllantitativetraits.Butthiskindofdistanceisaffectedstronglybyenvironmentalfactors.Soitisdifficulttoreflecttheactualgeneticdifferencebetweenparentpopulations.Recently,scientistspaymoreattentiontopredictheterosiswithgeneticdistanceestimatedfromproteinandDNApolymorphisms.Thisisbecauseitcanreflectthegeneticdifferencebetweenpopulationstrulier.Inte…