Virology,病毒学,Introduction,1.The discovery of virus 2.Feature and conception of virus 3.Relationship between viruses and diseases of human being,1892年 发现第一个病毒-烟草花叶病毒,2.Feature and conception of virus,Feature,Conception,The most important difference between viruses and other microbes, RNA or DNA mode of multiplication - self replication,体积微小 结构简单 严格寄生 复制增殖,DNA or RNA non-cellural type,multiply only in living and susceptible cells,3. Relationship between viruses and diseases of human being,Basic Properties of Viruses,病毒的基本性状,(6版p2231),Outline,Size and Shape of Viruses Structure and Chemical Composition Multiplication of Viruses Effect of physicochemical agents on virus Classification of Viruses Viral Heredity & Variation (p8183),(6版p2231,8183),300250nm,葡萄球菌,烟草花叶病毒,立克次体450nm,衣原体390nm,15300nm,6595nm,70nm,腺病毒,30nm,脊灰病毒,40nm,乙脑病毒,100nm,流感病毒,10nm,卵白蛋白,噬菌体,1000nm,痘苗病毒,.Size and Shape of Viruses, Measuring unit (nanometer,nm) d=30300 nm visible only with EM,1.Size of virus,Divide into 3 types -small ,median and large virus (绝大数150nm),2. Shape of viruses,病毒的形态与大小,球形,杆状,子弹状,砖块状,蝌蚪状,2. Shape of viruses,中型病毒,50nm,50200nm,200300nm,1.Structure of virion,nucleic acid,peplomer (spike),capsid,nucleocapsid,capsomere,(Naked virus),envelope,viral core,Enveloped virus,成熟的、有感染性的、 完整的病毒颗粒,.Structure and Chemical Composition, Viral core-viral nucleic acid, Only one type of nucleic acid, either DNA or RNA diversity *double or single stranded (ds-/ss-) *circular or linear, in one piece or segmented *plus and minus strand,Viral genome (DNA or RNA),-determine infectivity, replication, heredity and variation of virus,（DNA病毒大多数为双链，RNA 病毒多数为单链）, Protein coat-capsid(衣壳),Consists of repeating polypeptide subunits called capsomere(壳粒) Symmetry in arrangement,three symmetric architecture, Function, protect participate in viral infection antigenicity,Helical symmetry,Cubic symmetry,Complex symmetry,Structure of the simplest virion: Nucleic acid + capsid =Nucleocapsid,五邻体,六邻体,(决定病毒的亲嗜性,介导病毒进入宿主细胞),(核衣壳), Envelope and spike, Enveloped virus, Composition of envelope, Peplomer or spike, Function,(virion nucleocapsid+envelope),(胞膜子粒 刺突),capsid,核酸,刺突,衣壳,包膜,病毒体的结构,核衣壳,DNA/RNA,核衣壳,裸病毒,包膜病毒,(裸病毒),病毒体 (包膜病毒),衣壳 核酸,（DNA/RNA）,包膜,2. Chemical composition of viruses, Nucleic acid, Protein, lipid and carbohydrate, structural protein non-structural protein,(capsid,matrix and envelope),病毒的复制周期,生物合成,1.Multiplication of virus,Mode of multiplication,- self -replication, Replicative cycle,adsorption/attachment penetration uncoating biosynthesis assembly & release,. Multiplication of Virus,Adsorption or attachment,Nonspecific adsorption Specific combination,-virion adsorb to specific receptor on the surface of susceptible cells,-static electricity-combination between virus and cell,(decide tissue or cell-tropism, such as gp120 of HIV-CD4 molecule),Uncoating,-The viral nuclei acid is released from the capsid,Penetration,naked virus-by endocytosis or viropexis enveloped virus-by fusion of viral envelope with host-cell membrane,(病毒胞膜与宿主细胞膜融合),(吞饮或胞饮),Biosynthesis, include: replication of nucleic acid and protein synthesis biosynthetic site,*DNA in the nucleus, RNA in the cytoplasm *protein in the cytoplasm,early protein (function protein) late protein (structural protein),(eclipse period,隐蔽期),Biosynthesis of ds-DNA virus,parental ds-DNA,early mRNA,early protein,in the cytoplasm,progeny ds-DNA,in nucleus,later mRNA,later protein,in the cytoplasm,半保留复制,利用核内依赖DNA 的RNA多聚酶转录,biosynthesis of early protein-依赖DNA的DNA聚合酶等,replication of progeny DNA,biosynthesis of late protein,DNA聚合酶,Biosynthesis of ss-RNA virus,parental ss-RNA,early protein,in the cytoplasm,acts directly as mRNA,ss-RNA(RNA),later protein,progeny ss-RNA,(复制中间型),-RNA must first transcribe the complementary plus strand,* ss-RNA virus,(依赖RNA的RNA聚合酶),+RNA acts as mRNA,Assembly & release,assembly and maturation,release,* naked virus * enveloped virus,assembly: DNA virus - in the nucleus RNA virus- in the cytoplasm,Replication cycle of virus,adsorption,biosynthesis,assembly and release,uncoating,protein and nucleic acid,penetration, progeny viruses produce cell effects-damage and lysis of cells,2. Abnormal multiplication of viral & interference, Abortive infection (顿挫感染),non-permissive cells & permissive cells(容纳性细胞), Interference, Defective virus,两种病毒同时感染同一种细胞,发生一种病毒抑制另一种病毒复制的现象称为干扰现象,指缺陷病毒与其完整病毒(非缺损病毒)同时感染同一细胞时, 能干扰完整病毒的增殖, 发挥干扰作用的缺陷病毒为缺陷干扰颗粒(DIP), defective interfering particle (DIP),紫外线、线和射线可灭活,耐抗生素