简介：本文回顾了中国果树种质资源工作的发展历史,总结了我国30余年果树种质资源工作取得的成就,指出中国果树种质资源在发展中存在的主要问题,并对今后开展种质资源基础性工作提出了发展建议。

简介：Thenon-classicalHLAclassIantigenHLA-GisanimmunemodulatorwhichinhibitsthefunctionsofTcells,NKcells,andtheDendriticcells(DC).Asaresult,HLA-Gexpressioninmalignantcellsmayprovidethemwithamechanismtoescapetheimmunesurveillance.Inmelanoma,HLA-Gantigenexpressionhasbeenfoundin30%ofsurgicallyremovedlesionsbutinlessthan1%ofestablishedcelllines.OnepossiblemechanismunderlyingthedifferentialHLAGexpressioninvivoandinvitroisthattheHLA-Ggeneisepigeneticallyrepressedinmelanomacellsinvitro.Totestthishypothesis,wetreatedtheHLA-GnegativemelanomacelllineOCM-1AwiththeDNAmethyltransferaseinhibitor5-aza-2'-deoxycytidine(5-AC)andanalyzedwhetherHLA-Gexpressioncanberestored.OurdatastronglysuggestthatHLA-GissilencedasaresultofCpGhypermethylationwithina5'regulatoryregionencompassing220bpupstreamofthestartcodon.Aftertreatment,HLA-GmRNAexpressionwasdramaticallyincreased.WesternblotandflowcytometryshowedthatHLA-Gproteinwasinduced.Interestingly,HLA-Gcellsurfaceexpressiononthe5-ACtreatedOCM-1AcellsismuchlessthanthatontheHLA-GpositiveJEG-3cellswhileasimilaramountoftotalHLA-Gwasobserved.Possiblemechanismsforthedifferencewereanalyzedinthestudysuchascellcold-treatment,peptideloadingandantigenprocessingmachinerycomponents(APM)aswellasβ2microglobulin(β2-m)expression.DatarevealedthattheAPMcomponentcalreticulinmightbeinvolvedinthelowerHLA-GsurfaceexpressiononOCM-1Acells.Takentogether,ourresultsindicatedthatDNAmethylationisanimportantepigeneticmechanismbywhichHLA-Gantigenexpressionismodulatedinmelanomacellsinvitro.Furthermore,tothefirsttime,wehypothesizedthatthedeficiencyofcalreticulinmightbeinvolvedinthelowHLA-Gsurfaceexpressiononthe5-ACtreatedOCM-lAcells.

简介：TounderstandtheDNA-methylationmediatedgenesilencingmechanisms,weanalyzedincellcultureofthepromoterfunctionoftheMAGE-A1gene,whichisfrequentlydemethylatedandover-expressedinhumanhepatocellularcarcinoma.WehaveestablishedthecorrelationoftheDNAmethylationofthepromoterCpGislandwithexpressionstatusofthisgeneinapaneloftheestablishedlivercancercelllines.ThecrucialCpGdinucleotide(s)withintheminimalpromotersubjectedtothecontrolmediatedbyDNAmethylationwithprofoundbiologicalfunctionswasalsodelineated.Furthermore,anovelsequence-specificDNA-proteininteractionatthe-30CpGdinucleotideupstreamofthegenewasfoundhavingavitalparttoplayintheDNAmethylationmediatedtranscriptionsilencingoftheMAGE-A1gene.OurresultswouldnotonlyprovidenewinsightsintotheDNAmethylationmediatedmechanismsovertranscriptionoftheMAGE-A1gene,butalsopavethewayforfurtherdefiningthecross-talkamongDNAmethylation,histonemodificationandchromatinremodelingindetail.

简介：目的探讨C57BL/6与ICR小鼠在博来霉素（BLM）致肺纤维化过程中的种属差异。方法8周龄雌性C57BL/6小鼠19只,ICR小鼠16只,分别经尾静脉一次性注射BLM150mg/kg,观察每组小鼠体重、生存率及肺组织病理改变。结果①C57BL/6与ICR小鼠最低体重分别发生在静脉注射处置后的7d和5d,最低体重分别为注射前的65.46%和73.21%,两组间无显著的统计学差异。②C57BL/6与ICR小鼠的生存率分别为36.84%和56.25%,两组间存在显著的统计学差异。③C57BL/6小鼠BLM注射后28d,在胸膜下及血管周围形成广泛、稳定的间质纤维化病理改变,而ICR小鼠肺组织未见明显纤维化形成。C57BL/6小鼠肺纤维化病理评分明显高于ICR小鼠（P〈0.001）。结论BLM诱导的肺纤维化作用在C57BL/6与ICR小鼠间存在着明显的种属差异。C57BL/6小鼠较ICR小鼠更适于复制博来霉素诱导的肺纤维化动物模型。

简介：栽培一粒小麦是普通小麦的近缘种,遗传多样性丰富,蕴含丰富的抗病基因,是小麦抗病性改良的重要资源。本文对栽培一粒小麦抗白粉病材料3AA30的抗白粉病基因进行了遗传分析和分子标记定位。结果表明,3AA30中含有一个隐性抗白粉病基因,暂命名为ml3AA30,找到了5个与该基因连锁的SSR分子标记Xgwm6、Xcfd39、Xcfa2185、Xcfa2141、Xcfa2155及2个STS标记Xmag2170、Xmag1491,并构建了ml3AA30的遗传连锁图,将该基因定位在小麦5A染色体长臂上。本研究为小麦抗病育种提供了新的抗源材料。

简介：目的：观察Kozak序列（＋4G）对稳定转染的人淀粉样前体蛋白（hAPP751）-EGFP融合真核表达载体在CHO细胞中表达的影响,为APP的水解代谢研究提供细胞模型。方法：分别将含Kozak序列（＋4G）和不含Kozak序列的hAPP751全长基因片段亚克隆入pEGFP-N1表达载体,得到pEGFP-hAPP751（＋4G）和pEGFP-hAPP751重组质粒,转染CHO细胞,通过G418筛选稳定转染细胞株,再用倒置荧光显微镜挑取绿色荧光强的细胞进行亚克隆,并观察融合蛋白的表达强度和细胞定位,最后用EGFP抗体通过Western印迹检测融合蛋白。结果：PCR、酶切和测序证明将含Kozak序列（＋4G）和不含Kozak序列的hAPP751全长基因片段分别连入了真核表达载体pEGFP-N1中;荧光显微镜下观察pEGFP-hAPP751（＋4G）稳定转染细胞的细胞膜和细胞质产生较强的绿色荧光,其中在细胞质中成不均匀颗粒状分布,Western印迹检测到相对分子质量约156000的融合表达蛋白,与预期相符;pEGFP-hAPP751转染细胞,其绿色荧光十分微弱且在整个细胞均匀分布,Western印迹检测到相对分子质量约26000的EGFP,但检测不到预期的hAPP751-EGFP融合表达蛋白。结论：Kozak序列（＋4G）可以明显促进hAPP751的表达,获得稳定转染且高水平融合表达hAPP751-EGFP的细胞株。