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1.
稻纵卷叶螟对杂交水稻及常规水稻的生态反应   总被引:6,自引:0,他引:6  
钱希 《生态学杂志》1993,12(6):21-24
稻纵卷叶螟对杂交水稻及常规水稻的生态反应钱希(国营黄海农场,江苏省响水县224624)EcologiealResponsesofRiceCasewormtoHybridRicesandTraditionalRices¥QianXi(TheStateFarmofYellowSea,XiangshuiCounty,Jiangsu,Province224624).ChineseJournalofEcology,1993,12(6):21-24.Tostudytheeffectofricecultivarsontheoviposition,emergence,wormdevelopmentandnaturalenemvparasitionofcasewormandlossescausedbythepest,observationshavebeenmadeon16ricecultivarsinHuanghaiStateFarminNorthernJiangsuprovince,wherecasewormgraduallybecomemoreandmorevi-olentsincethechangesincultiva  相似文献   

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胱天蛋白酶(caspase)的前结构域   总被引:1,自引:0,他引:1  
胱天蛋白酶 (caspase)是白细胞介素 1β转化酶(interleukin 1βenzyme ,ICE)家族的总称 ,Caspase(cysteineaspartate specialproteases)的含义是该类蛋白酶的活性部位为极为保守的半胱氨酸 (cysteine)残基 (取第一个字母“c”) ,又特异性切割底物的天冬氨酸 ,用“aspase”表示 ,简称caspase ,该酶在细胞凋亡过程中起关键作用 ,是目前研究的热点。现已发现的caspase有 14种 ,它们均以无活性的酶原的形式存在 ,包括一个N末端前结构域 (p…  相似文献   

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细胞衰老揭秘为研究Werners综合征发病的基因机制,分子生物学家Guarente和Davidsinclair利用酵母Saccharomycescerevisiae进行研究。这是因为Werners的特征是早衰,而酵母Saccharomycesce...  相似文献   

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Itwasrecentlyevidencedthatmetabolicdisturbancesoffolicacidarecloselyrelatedtocardiovasculardiseasesandbirthdefects.5,10MTHFRisanimportantenzymeinthefolicacidmetabolicsystem.DecreaseinMTHFRactivitymayinducetheappearanceofhyperhomocysteinemia,whichmaycaus…  相似文献   

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细胞凋亡中的关键蛋白酶—Caspase—3   总被引:20,自引:0,他引:20  
在哺乳动物细胞凋亡执行阶段起重作用的一系列半胱氨酸蛋白酶基因相继被克隆。Caspase-3(又称CPP32,Yama,apopain)被认为是各种凋亡刺激因子激活的caspase家族中的关键蛋白酶,活性caspase-3可作用于一些其他caspase成员,并降解凋亡细胞中的某些蛋白质。Casepase-3抑制物是细胞凋亡抑制剂,有希望成为治疗因细胞过度死亡所致相关疾病的重要分子。  相似文献   

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Auxinisatypeofplanthormoneexistingextensively[1].Itregulatesmanyprocessesinplantdevelopment[2,3].Accordingtothe“acidgrowththeory”,auxinstimulatesaseriesofreactionandthenpromotescellgrowthbybindingtheABPlocatedincellmembrane[4,5].Thestudiesontobaccomutantexhi…  相似文献   

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Insectsarethemostsuccessfulanimalgroupintermsofnumbersofspecies.Althoughmanyfactorsmustcontributetotheprofusionofinsectspecies,onekeyelementisprobablyadevelopmentalplanthatincorporatesmetamorphosisanddiapause.Diapauseisacomplexadaptativeresponsewhichi…  相似文献   

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Anorganism,S.cerevisiaewidelyusedinbrewing,bakingandinethanolproductionprocessesisnotabletohydrolysestarch.ThusthetraditionalconversionofstarchintoethanolandCO2dependsontheadditionoftheenzymespriortofermentation,whichleadstoliquificationandsaccharificat…  相似文献   

9.
线粒体与细胞凋亡机制   总被引:5,自引:0,他引:5  
细胞凋亡是生理性的细胞死亡过程,受到多种基因的精确调节,一类被统称为caspase的半胱氨酸蛋白酶是细胞凋亡程序的执行者,综们被激活后作用于细胞内的一些蛋白质,经起细胞凋亡。线粒体中含有许多凋亡相关因子,在凋亡信号转导中起着重要作用。细胞受到凋亡刺激后,细胞色素c、AIF、caspase-9等凋亡相关因子从线粒体中释放出来。细胞色素c通过和Apaf-1、caspase-9相互作用,激活caspas  相似文献   

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1IntroductionItiswellknownthatnervecellsworkinnoisyenvironment,andnoisesourcesrangingfrominternalthermalnoisetoexternalperturbation.Onepuzzlingproblemishowdonervecellsaccommodatenoiseincodingandtransforminginformation,recentresearchshowsthatnoisemayp…  相似文献   

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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.  相似文献   

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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.  相似文献   

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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.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
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  相似文献   

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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.  相似文献   

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