是一类非细胞型微生物PPT课件

特性特性病毒病毒细菌细菌真菌真菌滤菌器滤菌器+ -结结 构构非细胞非细胞原核细胞原核细胞真核细胞真核细胞细胞壁细胞壁-+核酸类型核酸类型DNA或或RNADNARNADNARNA人工培养人工培养-+增殖方式增殖方式复制复制二分裂二分裂有性或无性有性或无性抗生素抗生素-+干扰素干扰素+-第1页/共68页形态 大小: （纳米，nm） The largest : （300X100 nm, 痘病毒） The smallest: 10 nm 形态：球形或杆状，也有复合状第2页/共68页第3页/共68页第4页/共68页第5页/共68页第6页/共68页HIV第7页/共68页Bacteriophage T4第8页/共68页结构 基本结构 核心 Viral core 衣壳 Capsid 辅助结构 包膜 Envelope 其他 病毒体 Virion 核衣壳 Nucleocapsid第9页/共68页核心功能 病毒核酸的特性：第10页/共68页病毒衣壳 成分：蛋白质 由壳粒组成。壳粒是衣壳的形态学亚单位，多肽分子是衣壳的化学亚单位 功能 保护病毒核酸 参与感染过程 具有抗原性第11页/共68页按壳粒排列方式的对称型 螺旋对称型（helical symmetry） 20面体立体对称型（icosahedral symmetry） 复合对称型（complex symmetry）第12页/共68页病毒包膜 是包绕在病毒核衣壳外面的双层膜 主要成分是蛋白质、多糖及脂类，常以糖蛋白或脂蛋白形式存在 蛋白质是由病毒基因编码，多糖、脂类来自宿主细胞膜、核膜或空泡膜第13页/共68页包膜特性与功能 有包膜的病毒以“出芽” 方式释放 有包膜病毒对脂溶剂（如乙醚、氯仿）敏感，能灭活病毒，乙醚常用于鉴定病毒有无包膜 功能 维护病毒体结构的完整性 具有与宿主细胞膜亲和及融合的性能 具有病毒抗原的特异性第14页/共68页病毒复制 复制周期 吸附、穿入、脱壳、生物合成、装配与释放 病毒本身没有独立的蛋白合成酶系统，必须借助宿主细胞的蛋白合成体系合成病毒蛋白 病毒复制周期时间因病毒而异 腺病毒25h 小RNA病毒6-8h 流感病毒15-30h第15页/共68页dsDNA病毒复制示意图第16页/共68页+ssRNA病毒复制示意图第17页/共68页+ssRNA逆转录病毒复制示意图第18页/共68页吸附 通过病毒体表面的配体蛋白与易感细胞表面特异性受体相结合 吸附过程可在几分钟到几十分钟内完成第19页/共68页穿入 吞饮：无包膜病毒被宿主细胞吞噬，进入胞内 融合：有包膜病毒的包膜与宿主细胞膜直接融合，病毒核衣壳进入细胞 直接穿入：第20页/共68页脱壳 在细胞溶酶体酶的作用下，脱去衣壳蛋白释放病毒核酸第21页/共68页生物合成 早期蛋白合成阶段 转录、翻译而产生病毒生物合成中必需的酶类及某些抑制或阻断细胞核酸和蛋白质合成的非结构蛋白 晚期蛋白合成阶段 复制病毒核酸，转录、翻译而产生病毒的结构蛋白 隐蔽期 生物合成阶段用电镜方法在细胞查不到完整病毒，用血清学方法也测不到病毒抗原 各病毒隐蔽期长短不一，第22页/共68页装配 无包膜病毒 先形成空心衣壳，核酸从衣壳裂隙进入形成核衣壳 有包膜病毒 核衣壳与细胞的膜系统（浆膜或核膜）结合形成包膜 包膜的蛋白质（包括糖蛋白）是由病毒基因组编码，故具有病毒的特异性和抗原性 装配的部位 除痘病毒外，DNA病毒均在细胞核内装配 RNA病毒与痘病毒则在细胞浆内装配第23页/共68页释放 无包膜病毒 均以破胞方式释放 有包膜的病毒 以出芽方式释放到细胞外 通常细胞不死亡，仍能继续分裂增殖第24页/共68页病毒增殖异常 顿挫感染 缺陷病毒 干扰现象形成包涵体 某些病毒在宿主细胞内增殖，其细胞质或细胞核内会出现一种光学显微镜下可见的斑块结构，称包涵体。它是病毒在细胞内增殖的场所第25页/共68页顿挫感染 原因 宿主细胞不能提供病毒复制所需的酶、能量或成份 病毒虽被复制，但不能装配释放第26页/共68页缺陷病毒 因病毒基因组不完整或有点突变而不能进行正常复制的病毒，当与辅助病毒共同培养，如能为其提供缺乏的物质，则缺陷病毒也能培殖 腺病毒相关病毒（缺陷病毒）与腺病毒（辅助病毒） 丁型肝炎病毒（缺陷病毒）与乙型肝炎病毒（辅助病毒）第27页/共68页干扰现象 两种病毒感染同一细胞时，一种病毒会干扰另一病毒复制 原因 与干扰素（IFN）产生有关 病毒改变了宿 主细胞代谢途径 意义 联合使用疫苗第28页/共68页理化因素对病毒的影响灭活 病毒受理化因素作用后，失去感染性 灭活病毒仍保留某些特性，如抗原性、红细胞吸附、细胞融合等第29页/共68页物理因素 温度 病毒耐冷不耐热。-70C长期保存。冻融可杀死病毒 60C 30 min或100C数秒即可杀死病毒，但HBV需100C 10 min方可杀死 有包膜病毒比无包膜病毒对热更敏感 pH 多数在pH 59范围稳定 肠道病毒耐酸（pH 35） 射线 X线、射线可将病毒核酸致死性断裂，从而杀死病毒第30页/共68页化学因素 脂溶剂：乙醚、氯仿、去氧胆酸盐 有包膜病毒敏感。无包膜病毒无作用（如肠道病毒） 消毒剂：过氧乙酸、甲醛、戊二醛、卤素 杀死大多数病毒，但病毒对消毒剂抵抗力比细菌强，尤其是无包膜病毒 常用甲醛来制备灭活疫苗 其他 抗生素：对病毒无作用 中草药：有一定作用第31页/共68页 病毒的变异现象 感染性变异（毒力变异） 条件致死株：减毒活疫苗（脊灰） 抗原性变异 耐药性变异 机制基因突变基因重组第32页/共68页病毒与其他微生物的比较第33页/共68页小结 病毒的概念 病毒的结构与化学组成 病毒的复制 理化因素对病毒的影响第34页/共68页14. Techniques used to Study Viruses Living hosts. Man. Pasteur used rabbits to study and develop rabies vaccines. Walter Reed developed a mouse model of yellow fever. Transgenic animals, particularly mice invaluableEmbryonated eggs used to propagate viruses in the early decades of this century. Effective for the isolation & culture of many viruses e.g.influenza.第35页/共68页15. Cell Culture methods Whole organ cultures, progressed to methods involving individual cells; primary cell cultures which can be maintained for a short period in culture); or immortalized cell lines, which grow in culture indefinitely. Viruses can be grown in them.第36页/共68页16. Quantifying viruses. The plaque assay - dilutions of the virus are used to infect a cultured cell monolayer, covered with agar to restrict virus diffusion virus. Results in localized cell killing & the appearance of plaques. The number of plaques directly relates to numbers of infectious virus particles applied to the plate. Many other approaches. 第37页/共68页17. Other practical approaches Serology Structural studies, purification, EM, X-ray. Biochemical, electrophoresis Genetic Molecular biology, nucleic acid sequencing. 第38页/共68页Replication 14. Exit Some viruses cause cell lysis. Unenveloped. Other viruses bud through a cell membrane, aquiring an envelope. Can be the plasma membrane e.g. HIV-1. Can be nuclear or golgi membranes. 第39页/共68页2. Big fleas have little fleas upon their backs to bite them; and little fleas have lesser fleas and so ad infinitum. Viruses consist of proteins, nucleic acids and sometimes lipids. However there are other infectious agents studied by virologists. Viroids small (200-400nt), circular RNAs, possessing no capsid or envelope. Associated with certain plant diseases. They are infectious obligate intracellular parasites. Virusoids are satellite, viroid-like RNAs, larger than viroids (approximately 1000nt). Depend on the presence of virus replication for multiplication (hence satellite), they are packaged into virus capsids as passengers. Present in animals and plants. Associated with disease. 第40页/共68页3. PrionsPrions. “pree ons” believed to consist of a single type of protein with no nucleic acid component. The prion protein & the gene which encodes it are also found in normal uninfected cells. These agents are associated with infectious and inherited diseases, such as Creutzfeldt-Jakob disease in humans, scrapie in sheep & bovine spongiform encephalopathy (BSE) in cattle. 第41页/共68页ve RNA-ve RNApolProteins-ve RNA+ve RNARI第42页/共68页Genomes 14Ambisense Genomes Some ssRNA viruses are ambisense, since they are part (-)sense & part (+)sense: 5 ends are +ve, 3 ends are ve.第43页/共68页Genomes 15. Segmented/multipartite. Can be confusing, ss or ds. Segmented genomes have 2 or more pieces of nucleic acid packaged in the same particle e.g orthomxyo viruses.(7/8 in flu, packaging problem) Multipartite genomes are segmented but each segment is contained in a different particle e.g bipartite Comoviruses, both particles infect cell. segmentedMultipartite, DNA as well第44页/共68页Genomes 16. DNA. Small genomes e.g.bacteriophage M13 6.4 Kb ss circular DNA. 10 genes By convention genome is +strand. 90% genome is coding. + RF-strand transcribed to make mRNAand then proteins +ve strand nickedextended in rolling circle + Specifically cleavedAnd recircularised第45页/共68页Genomes 17. Phage l.l. Linear ds DNA about 50Kb. Cohesive ss DNA termini 12 nucleotides long, the cos site. Facilitates circularisation and replication cycle. Concatemers formed and then resolved to reconstitute genome. TCCAGCGGCGGG AGGTCGCCGCCC3 limportant sequences at the end of the linear virus genomes are a very common feature.第46页/共68页Genomes 18. Phage T4 Large linear ds DNA 160Kb Genome exhibits terminal redundancy. Another common feature of linear genomes. A B C D E A B C D E A B C D E A B C D EA B C D E A B C D E A B C D E A B C D E During replication concatemers are formed. Endonuclease recognises and cuts at this terminal redundancy, which is then regenerated. 第47页/共68页Genomes 19. Transcriptional control in prokaryotes is sophisticated. That said extensive use of polycistronic mRNAs is made. Genomes are dense M13 10 genes, 10 transcripts 90% usage Genomes of eukaryotes are denser Polyoma, ds DNA circular 5kb genome Six genes, both strands, overlapping.第48页/共68页Genomes 20. Adeno viruses Larger 30-38kb linear ds genomes infecting eukaryotes. Code for about 30-40 proteins These viruses are genetically very similar to the host cells which they infect. Terminal sequences are inverted repeats Complicated functional structures can form at these pointsTGTGTGCACACAACACACGTGTGT第49页/共68页第50页/共68页Viral Replication. Attachment and penetration Uncoating, nucleic acid and protein synthesis Assembly and exit. 第51页/共68页Replication 2. Particle/infectivity ratio can be low. Sometimes only 1 in 1000 virions are infectious. It makes the study of replication difficult because most infections are abortive. Study of synchronously infected cells is useful.第52页/共68页Replication 3. Eclipse phase: low amounts of parental infectious material present. Genome replication has been initiated. Duration, minutes-hrs.第53页/共68页Replication 4. Maturation phase:viral material accumulates in cell or surrounding medium. Cells infected with lytic viruses become metabolically disordered and die, viral production ceases. Titres slowly drop. Cells infected with non lytic viruses can continue to produce viral particles indefinitely. 第54页/共68页Replication 5. Reproductive cycle less than an hour with many bacteriophage, 6-8hrs in picornaviridae and more than 40 hrs in herpesviridae. Cells infected with polio virus can yield more than 100000 copies of virus per infected cell.第55页/共68页Replication 6. Infection may be: productive, i.e. entry into permissive cells followed by virion formation. abortive, i.e. entry into a non permissive cell which does not result in virion formation; there can be many reasons for non-permissiveness e.g. no receptor. restringent or restrictive, cell is transiently permissive and a few virus are produced. Virus production stops but the genome remains in the cell, examples include Epstein Barr Virus and herpes simplex virus. This kind of infection may still have serious consequences e.g cell transformation and cancer. 第56页/共68页History of Virology Viruses are probably as old as life on earth. Ancients were aware of viral diseasesPerhaps the first written record of a virus infection consists of a heiroglyph from Memphis, drawn in approximately 1400BC, which depicts a temple priest called Siptah showing typical clinical signs of paralytic poliomyelitis第57页/共68页 Smallpox, endemic in China by 1000BC. Recognizing that survivors of smallpox outbreaks were protected from subsequent infection, the practice of variolation developed. Involved inhalation of dried crusts from smallpox lesions, or in later modifications, inoculation of the pus from a lesion into a scratch on the forearm. Practice survived until this century. 第58页/共68页On May 14, 1796, Edward Jenner used cowpox-infected material obtained from the hand of Sarah Nemes, a milkmaid from Berkley in Gloucestershire to vaccinate 8 year old James Phipps. On July 1, 1796, Jenner challenged the boy by deliberately inoculating him with material from a real case of smallpox ! He did not become infected!第59页/共68页 In 1892, Dmitri Iwanowski, a Russian botanist, showed that extracts from diseased tobacco plants could transmit disease to other plants after passage through ceramic filters fine enough to retain the smallest known bacteria. Generally recognised as the beginning of Virology In 1898, Martinus Beijerinick confirmed & extended Iwanowskis results on tobacco mosaic virus & was the first to develop the modern idea of the virus, which he referred to as contagium vivum fluidum (soluble living germ)第60页/共68页C o m p i l e d f r o m V i r u s T a x o n o m y , t h e S i x t h R e p o r t o f t h e I n t e r n a t i o n a l C o m m i t t e e o n T a x o n o m y o f V i r u s e s ( I C T V ) 1 9 9 5 . N . B : y o u c a n s e a r c h t h i s d o c u m e n t u s i n g t h e F i n d c o m m a n d o f t h e b r o w s e r ( E d i t M e n u )6 3 U - 1 1 v i r u s , B u n y a v i r i d a e7 5 V - 2 3 7 4 v i r u s , B u n y a v i r i d a e7 5 V - 2 6 2 1 v i r u s , B u n y a v i r i d a e7 8 V - 2 4 4 1 v i r u s , B u n y a v i r i d a e A b a d i n a v i r u s , R e o v i r i d a eA b e l s o n m u r i n e l e u k e m i a v i r u s , R e t r o v i r i d a eA b r a s v i r u s , B u n y a v i r i d a eA b r a x a s g r o s s u l a r i a t a c y p o v i r u s 8 , R e o v i r i d a eA b r a x a s g r o s s u l a r i a t a N P V , B a c u l o v i r i d a eA b s e t t a r o v v i r u s , F l a v i v i r i d a eA b u H a m m a d v i r u s , B u n y a v i r i d a eA b u M i n a v i r u s , B u n y a v i r i d a eA b u t i l o n m o s a i c v i r u s , G e m i n i v i r i d a eA c a d o v i r u s , R e o v i r i d a eA c a l y p h a y e l l o w m o s a i c v i r u s , G e m i n i v i r i d a eA c a n t h o l y d a e r y t h r o c e p h a l a N P V , B a c u l o v i r i d a eA c a r a v i r u s , B u n y a v i r i d a eA c c i p t r i d h e r p e s v i r u s 1 , H e r p e s v i r i d a eA c h a e a j a n a t a N P V , B a c u l o v i r i d a eA c h e r o n t i a a t r o p a s v i r u s , T e t r a v i r i d a eA c h e t a d o m e s t i c a d e n s o v i r u s , P a r v o v i r i d a eA c h o l e p l a s m a p h a g e O c 1 r , I n o v i r i d a eA c h o l e p l a s m a p h a g e 1 0 t u r , I n o v i r i d a eA c h o l e p l a s m a p h a g e L 2 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e L 5 1 , I n o v i r i d a eA c h o l e p l a s m a p h a g e M 1 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e M V - L 1 , I n o v i n d a eA c h o l e p l a s m a p h a g e M V G 5 1 , I n o v i r i d a eA c h o l e p l a s m a p h a g e 0 1 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e v l , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e v 2 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e v 4 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e v 5 , P l a s m a v i r i d a eA c h o l e p l a s m a p h a g e v 7 , P l a s m a v i r i d a eA c h r o i a g r i s e l l a N P V , B a c u l o v i r i d a eA c i d a l i a c a r t i c c a r i a N P V , B a c u l o v i r i d a eA c l e r i s g l o v e r a n a N P V , B a c u l o v i r i d a eA c l e r i s v a r i a n a N P V , B a c u l o v i r i d a eA c r o b a s i s z e l l e r i e n t o m o p o x v i r u s , P o x v i r i d a eA c r o n i c t a a c e r i s N P V , B a c u l o v i r i d a eA c t e b i a f e n n i c a N P V , B a c u l o v i r i d a eA c t i a s s e l e n e C y p o v i r u s 4 , R e o v i r i d a eA c t i a s s e l e n e N P V , B a c u l o v i r i d a eA c t i n o m y c e t e s p h a g e 1 0 8 / 0 1 6 , M y o v i r i d a eA c t i n o m y c e t e s p h a g e 1 1 9 , S i p h o v i r i d a eA c t i n o m y c e t e s p h a g e A 1 - D a t , S i p h o v i r i d a eA c t i n o m y c e t e s p h a g e B i r , S i p h o v i r i d a eA c t i n o m y c e t e s p h a g e f 1 1 5 - A , S i p h o v i r i d a eA c t i n o m y c e t e s p h a g e f 1 5 0 A , S i p h o v i r i d a eA c t i n o m y c e t e s p h a g e f 3 1 C , S i p h o v i r i d a eActinomycetes phage M1, SiphoviridaeActinomycetes phage MSP8, SiphoviridaeActinomycetes phage P-a-1, SiphoviridaeActinomycetes phage R1, SiphoviridaeActinomycetes phage R2, SiphoviridaeActinomycetes phage SK1, MyoviridaeActinomycetes phage SV2, SiphoviridaeActinomycetes phage VP5, SiphoviridaeAdelaide River virus, RhabdoviridaeAdeno-associated virus 1, ParvoviridaeAdeno-associated virus 2, ParvoviridaeAdeno-associated virus 3, ParvoviridaeAdeno-associated virus 4, ParvoviridaeAdeno-associated virus 5, ParvoviridaeAdisura atkinsoni NPV, BaculoviridaeAdoxophyes orana NPV, BaculoviridaeAedes aegypti densovirus, ParvoviridaeAedes aegypti entomopoxvirus, PoxviridaeAedes aegypti NPV, BaculoviridaeAedes albopictus densovirus, ParvoviridaeAedes annandalei NPV, BaculoviridaeAedes atropalpus NPV, BaculoviridaeAedes epactius NPV, BaculoviridaeAedes nigromaculis NPV, BaculoviridaeAedes pseudoscutellaris densovirus, ParvoviridaeAedes scutellaris NPV, BaculoviridaeAedes sollicitans NPV, BaculoviridaeAedes taeniorhynchus NPV, BaculoviridaeAedes tormentor NPV, BaculoviridaeAedes triseriatus NPV, BaculoviridaeAedia leucomelas NPV, BaculoviridaeAeromonas phage 29, MyoviridaeAeromonas phage 37, MyoviridaeAeromonas phage 43, MyoviridaeAeromonas phage 44RR2.8t, MyoviridaeAeromonas phage 51, MyoviridaeAeromonas phage 59.1, MyoviridaeAeromonas phage 65, MyoviridaeAeromonas phage Aeh1, MyoviridaeAeromonas phage Aeh2, MyoviridaeAfrican cassava mosaic virus, GeminiviridaeAfrican green monkey cytomegalovirus, HerpesviridaeAfrican green monkey HHV-like virus, HerpesviridaeAfrican green monkey polyomavirus, PapovaviridaeAfrican horse sickness viruses 1 to 10, ReoviridaeAfrican swine fever virus, African swine fever-like virusesAG83-1746 virus, BunyaviridaeAG83-497 virus, BunyaviridaeAgaricus bisporus virus 1, UnassignedAgaricus bisporus virus 4, PartitiviridaeAgraulis vanillae virus, TetraviridaeAgrobacterium phage PIIBNV6, MyoviridaeAgrobacterium phage PS8, SiphoviridaeAgrobacterium phage PT11, SiphoviridaeAgrobacteriurn phage Y, SiphoviridaeAgrochola helvolva cypovirus 6, ReoviridaeAgrochola lychnidis cypovirus 6, ReoviridaeAgropyron mosaic virus, PotyviridaeAgrotis exclarnationis NPV, BaculoviridaeAgrotis ipsilon NPV, BaculoviridaeAgrotis segeturn cypovirus 9, ReoviridaeAgrotis segeturn NPV, BaculoviridaeAguacate virus, BunyaviridaeAhlum water-borne virus, TombusviridaeAino virus, BunyaviridaeAkabane virus, BunyaviridaeAKR (endogenous) murine leukemia virus, RetroviridaeAlabama argillacea NPV, BaculoviridaeAlajuela virus, BunyaviridaeAlcaligenes phage 8764, SiphoviridaeAlcaligenes phage A5/A6, SiphoviridaeAlcaligenes phage A6, MyoviridaeAlcelaphine herpesvirus 1, HerpesviridaeAlcelaphine herpesvirus 2, HerpesviridaeAlenquer virus, BunyaviridaeAletia oxygala NPV, BaculoviridaeAleutian disease virus, ParvoviridaeAleutian mink disease virus, ParvoviridaeAfalfa cryptic virus 1, PartitiviridaeAlfalfa cryptic virus 2, PartitiviridaeAlfalfa latent virus, CarlavirusAlfalfa mosaic virus, BromoviridaeAlfuy virus, FlaviviridaeAllerton virus, HerpesviridaeAlligatorweed stunting virus, ClosterovirusAllitrich herpesvirus 1, HerpesviridaeAllomyces arbuscula virus, UnassignedAlmeirim virus, ReoviridaeAlmpiwar virus, RhabdoviridaeAlphaea phasma NPV, BaculoviridaeAlsophila pometaria NPV, BaculoviridaeAlstroemeria mosaic virus, PotyviridaeAlstroemeria streak virus, PotyviridaeAlstroemeria virus, CarlavirusAltamira virus, ReoviridaeAlteromonas phage PM2, CorticoviridaeAmapari virus, ArenaviridaeAmaranthus leaf mottle virus, PotyviridaeAmathes c-nigrum NPV, BaculoviridaeAmazon lily mosaic virus, PotyviridaeAglais urticae cypovirus 2, ReoviridaeAglais urticae cypovirus 6, ReoviridaeAglais urticae NPV, BaculoviridaeAgraulis vanillae cypovirus 2, ReoviridaeAgraulis vanillae densovirus, ParvoviridaeAgraulis vanillae NPV, BaculoviridaeAndraca bipunctata GV, BaculoviridaeAneilema virus, PotyviridaeAngel fish reovirus, ReoviridaeAnhanga virus, BunyaviridaeAnhembi virus, BunyaviridaeAnisota senatoria NPV, BaculoviridaeAnomala cuprea entomopoxvirus, PoxviridaeAnomis flava NPV, BaculoviridaeAnomis sabulifera NPV, BaculoviridaeAnomogyna elimata NPV, BaculoviridaeAnopheles A virus, BunyaviridaeAnopheles 8 virus, BunyaviridaeAnopheles crucians NPV, BaculoviridaeAntequera virus, BunyaviridaeAnthela varia NPV, BaculoviridaeAnthelia hyperborea NPV, BaculoviridaeAntheraea eucalypti virus, TetraviridaeAntheraea mylitta cypovirus 4, ReoviridaeAntheraea paphia NPV, BaculoviridaeAntheraea pemyi cypovirus 4, ReoviridaeAntheraea pemyi NPV, BaculoviridaeAntheraea polyphemus NPV, BaculoviridaeAntheraea yamamai NPV, BaculoviridaeAnthonomus glandis PV, BaculoviridaeAnthoxan, thum latent blanching virus, HordeivirusAnthoxanthum mosaic virus, PotyviridaeAnthrenus museorum NPV, BaculoviridaeAnthriscus virus, CarlavirusAnthriscus yellows virus, SequiviridaeAnticarisia gemmatalis MNPV, BaculoviridaeAntitype xanthomista cypovirus 6, ReoviridaeAotine herpesvirus 1, HerpesviridaeAotine herpesvirus 2, HerpesviridaeAotine herpesvirus 3, HerpesviridaeApamea anceps GV, BaculoviridaeApamea anceps NPV, BaculoviridaeApamea sordens GV, BaculoviridaeApanteles fumiferanae virus, PolydnaviridaeApeu virus, BunyaviridaeAphid lethal paralysis virus, PicornaviridaeAphodius tasmaniae entomopoxvirus, PoxviridaeApocheima cinerarius NPV, BaculoviridaeApproved Names of All Known Viruses: There are thousands第61页/共68页Serious ThreatennWalter Reed discovered the first human virus Yellow fever virus In 1901nHBV was discovered during 1963 to 1970. It turned out to be the most serious health problem in ChinanWHO declared the deracination of Small Pox In 1980nAIDS patients were reported in USA In 1981. The HIV was recognised in 1983nThere are maybe still a lot of viruses we dont know第62页/共68页Helical Capsids Helix can be defined mathematically by two parameters: amplitude (diameter) & pitch (the distance covered by each complete turn of the helix) 第63页/共68页Icosahedra 20 equilateral triangles arranged into a sphere based on 2-3-5 rotational symmetry Bacteriophage X174. As simple as it comes. 60 identical subunits form a capsid. 3 protein subunits per triangular face. Most have more. 第64页/共68页Complicated Virus Structures第65页/共68页病毒立体对称结构