病毒的遗传与变异
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1、Gene Mutation 基因突变
• Virulence changes • ※ Conditional lethal mutant
条件致死突变株
eg. temperature sensitive (ts) mutant • ※ Host-range mutant (hr)
宿主范围突变株 • Drug-resistant mutant 耐药突变株
Viral infection: the process of virus entering and multiplying
in the human or animal body. 病毒侵入人及动物机体并在其中增殖的过程 Viral pathogenesis:
the interaction between viral & host factors that leads to disease.
2020/11/26
2 、Recombination / Reassortment 重组与重配
• Recombination 两个病毒基因组间核酸序列交换、组合
• Reassortment ( segmented genomes) RNA viruses: influenza virus
分节段的RNA病毒基因组之间，通过基 因片段交换使子代基因组发生突变
• 很小 (250-400nt),杆状 RNA 分子，有二级结构 • 无衣壳或包膜 • 在核内增殖，严格细胞内寄生 • 多与植物疾病相关
2020/1来自百度文库/26
satellites卫星病毒 / Virosid拟病毒
• 特点：1 是RNA病毒 ，500-2000bp
•
2 复制需要辅助病毒
•
3 与辅助病毒基因无同源性
• Questions
– Describe the types and routes of viral infection. – What is interferon干扰素? List the bioactivities of it?
2020/11/26
Section 1 Viral Infection 病毒的感染
2020/11/26
IV、 ※ Types of infection 感染类型
– ※ Unapparent infection 隐性感染 (subclinical infection): Virus multiply in the host cells without causing clinical
2020/11/26
2020/11/26
2020/11/26
Viroids(类病毒)
• Viroids are small (250-400nt , Nucleotide), RNA molecules with a rod-like secondary structure ，which possess no capsid or envelope ， which are associated with certain plant diseases.
•
4 所致疾病与辅助病毒无关
• 有两类：一类可编码自身衣壳蛋白
另一类为卫星病毒RNA分子
2020/11/26
Prions 朊粒
• consist of a single type of protein molecule with no nucleic acid component.
• These agents are associated with diseases such as Creutzfeldt-Jakob disease克雅病（亚急性海绵状脑病 ） in humans, scrapie痒病in sheep & bovine spongiform encephalopathy (BSE)牛海绵状脑病in cattle.
2020/11/26
2020/11/26
※This chapter will focus on
• Conceptions
Horizontal and Vertical transmission水平传播及垂直传播, inapparent and apparent infection隐性感染及显性感染, Persistent viral infection持续性病毒感染， Latent infection潜伏性感染, Chronic infection慢性感染, Slow virus infection慢发病毒感染, Inclusion body包涵体
Viral Genetics and Variation 病毒的遗传与变异
2020/11/26
Conceptions
• Genetics遗传: After virus replicates , the characters on the progeny virus are similar with the previous generation.
• For humans and animals --24 families, --DNA: 7; RNA: 17 for humans
2020/11/26
basis of classification 病毒分类依据
• Virion structure and proteries病毒结构与性质 • Virion morphology and size病毒大小和形态 • Symmetry of nucleocapsids 核衣壳对称性 • Envelope 有无包膜 • Physicochemical properties 理化特性 • Antigenic properties抗原性 • Biologic properties生物学特性
the transmission of viruses from parent to the young via placenta, birth canal.
亲代通过胎盘或产道传给子 代
2020/11/26
III. Routes of transmission 播散方式
Local infection → Systemic infection Direct contact ：细胞→细胞 blood：侵入部位→血液 neural system：感染部位神经元
2020/11/26
The characteristic of viral infection
a. A particular disease may be caused by several viruses that have a common tissue tropism取向 (preference选择).
(several days to weeks); e.g., common cold, influenza, hepatitis A. ✓ Persistent viral infection 持续性病毒感染:
viruses persist in the host for long time period, several months or years or decades ，sometimes for the whole life.
2020/11/26
II. Modes of viral transmission 传播方式
– ※Horizontal transmission水平传播:
direct host-to-host transmission of viruses. 人与人不同个体间的传播
– ※ Vertical transmission垂直传播:
（1） Phenotypic mixing or transcapsidation 表型混合与核壳转 移
（2）genotype mixing 基因型混合 （20203/11）/26 enhancement 增强
(1) Phenotypic mixing表型混 合
• The genome of virus A can be coated with the surface protein of virus type B 两株病毒共同感染同一细胞时，一种病毒 复制的核酸被另一病毒所编码的蛋白质衣 壳或包膜包裹，不是遗传物质的交换，而 是基因产物的交换
3 、integration整合
• 病毒基因组与细胞基因组之间的重组
2020/11/26
（二） Non-Heritable variation 非遗传型变异
• Interactions：when two genetically distinct viruses infect a cell. 4 different phenomena can ensue 继发
制
• Heritable variation遗传型变异 因病毒遗传物质核酸发生了改变，导致其
变异后的性状可遗传给子代病毒。 • Non- Heritable variation非遗传型变异
又称基因产物的相互作用，因病毒核酸并 未发生改变，所以此变异一般不能遗传。
2020/11/26
（一） Heritable variation 遗传型变异
(•3实)e质nh：a核nc酸em未e重n组t 增合，强没有遗传性 两病毒混合培养，一病毒能增强另 一病毒的产量
2020/11/26
(4)complementation互补
2020/11/26
2020/11/26
国际病毒分类委员会ICTV
• By 2001 --66 families科, 9 subfamilies亚科 --244 genera属
※ Apparent infection 显性感染
Viruses multiply in host cells and cause clinical symptoms. ✓ Acute infection 急性病毒感染: short incubation, sudden onset, and short duration of disease
2020/11/26
I. tract of viral infection 感染途径
– Respiratory tract 痰、唾液、飞沫、气溶胶 – Alimentary tract 饮水、食物 – Skin 动物咬伤、昆虫叮咬 – Blood 输血、注射、针刺、器官移植 – Genital tract 性交 – Urinary tract 洗浴 – placenta, birth canal 孕期、分娩
• Variation变异: After virus replicates , the characters on the progeny virus are different with the previous g202e0/11n/26eration.
一、 Variation mechanism 病毒变异的机
e.g., HAV, HBV, HCV, HDV, HEV, etc hepatitis.
b. A particular virus may cause several different diseases or no observable引人注意的 symptoms.
e.g., HSV单纯疱疹病毒-1pharyngitis咽炎, herpes labialis 唇疱疹，genital herpes生殖道疱疹, encephalitis脑炎, keratoconjunctivitis角膜结膜炎.
• transcapsidation核壳转移： 无包膜病毒发生的表型混合
2020/11/26
(2)genotype mixing 基因型混 合
• Genome A + genome B → same capsid 衣壳
• Capsid A + capsid B → same envelope 包膜
symptoms or causing mild symptoms.
Significance: important source of infection; 重要传染源 acquire immunity; 获得免疫力 misdiagnose or fail to diagnose;易误诊和漏
诊
2020/11/26
• Virulence changes • ※ Conditional lethal mutant
条件致死突变株
eg. temperature sensitive (ts) mutant • ※ Host-range mutant (hr)
宿主范围突变株 • Drug-resistant mutant 耐药突变株
Viral infection: the process of virus entering and multiplying
in the human or animal body. 病毒侵入人及动物机体并在其中增殖的过程 Viral pathogenesis:
the interaction between viral & host factors that leads to disease.
2020/11/26
2 、Recombination / Reassortment 重组与重配
• Recombination 两个病毒基因组间核酸序列交换、组合
• Reassortment ( segmented genomes) RNA viruses: influenza virus
分节段的RNA病毒基因组之间，通过基 因片段交换使子代基因组发生突变
• 很小 (250-400nt),杆状 RNA 分子，有二级结构 • 无衣壳或包膜 • 在核内增殖，严格细胞内寄生 • 多与植物疾病相关
2020/1来自百度文库/26
satellites卫星病毒 / Virosid拟病毒
• 特点：1 是RNA病毒 ，500-2000bp
•
2 复制需要辅助病毒
•
3 与辅助病毒基因无同源性
• Questions
– Describe the types and routes of viral infection. – What is interferon干扰素? List the bioactivities of it?
2020/11/26
Section 1 Viral Infection 病毒的感染
2020/11/26
IV、 ※ Types of infection 感染类型
– ※ Unapparent infection 隐性感染 (subclinical infection): Virus multiply in the host cells without causing clinical
2020/11/26
2020/11/26
2020/11/26
Viroids(类病毒)
• Viroids are small (250-400nt , Nucleotide), RNA molecules with a rod-like secondary structure ，which possess no capsid or envelope ， which are associated with certain plant diseases.
•
4 所致疾病与辅助病毒无关
• 有两类：一类可编码自身衣壳蛋白
另一类为卫星病毒RNA分子
2020/11/26
Prions 朊粒
• consist of a single type of protein molecule with no nucleic acid component.
• These agents are associated with diseases such as Creutzfeldt-Jakob disease克雅病（亚急性海绵状脑病 ） in humans, scrapie痒病in sheep & bovine spongiform encephalopathy (BSE)牛海绵状脑病in cattle.
2020/11/26
2020/11/26
※This chapter will focus on
• Conceptions
Horizontal and Vertical transmission水平传播及垂直传播, inapparent and apparent infection隐性感染及显性感染, Persistent viral infection持续性病毒感染， Latent infection潜伏性感染, Chronic infection慢性感染, Slow virus infection慢发病毒感染, Inclusion body包涵体
Viral Genetics and Variation 病毒的遗传与变异
2020/11/26
Conceptions
• Genetics遗传: After virus replicates , the characters on the progeny virus are similar with the previous generation.
• For humans and animals --24 families, --DNA: 7; RNA: 17 for humans
2020/11/26
basis of classification 病毒分类依据
• Virion structure and proteries病毒结构与性质 • Virion morphology and size病毒大小和形态 • Symmetry of nucleocapsids 核衣壳对称性 • Envelope 有无包膜 • Physicochemical properties 理化特性 • Antigenic properties抗原性 • Biologic properties生物学特性
the transmission of viruses from parent to the young via placenta, birth canal.
亲代通过胎盘或产道传给子 代
2020/11/26
III. Routes of transmission 播散方式
Local infection → Systemic infection Direct contact ：细胞→细胞 blood：侵入部位→血液 neural system：感染部位神经元
2020/11/26
The characteristic of viral infection
a. A particular disease may be caused by several viruses that have a common tissue tropism取向 (preference选择).
(several days to weeks); e.g., common cold, influenza, hepatitis A. ✓ Persistent viral infection 持续性病毒感染:
viruses persist in the host for long time period, several months or years or decades ，sometimes for the whole life.
2020/11/26
II. Modes of viral transmission 传播方式
– ※Horizontal transmission水平传播:
direct host-to-host transmission of viruses. 人与人不同个体间的传播
– ※ Vertical transmission垂直传播:
（1） Phenotypic mixing or transcapsidation 表型混合与核壳转 移
（2）genotype mixing 基因型混合 （20203/11）/26 enhancement 增强
(1) Phenotypic mixing表型混 合
• The genome of virus A can be coated with the surface protein of virus type B 两株病毒共同感染同一细胞时，一种病毒 复制的核酸被另一病毒所编码的蛋白质衣 壳或包膜包裹，不是遗传物质的交换，而 是基因产物的交换
3 、integration整合
• 病毒基因组与细胞基因组之间的重组
2020/11/26
（二） Non-Heritable variation 非遗传型变异
• Interactions：when two genetically distinct viruses infect a cell. 4 different phenomena can ensue 继发
制
• Heritable variation遗传型变异 因病毒遗传物质核酸发生了改变，导致其
变异后的性状可遗传给子代病毒。 • Non- Heritable variation非遗传型变异
又称基因产物的相互作用，因病毒核酸并 未发生改变，所以此变异一般不能遗传。
2020/11/26
（一） Heritable variation 遗传型变异
(•3实)e质nh：a核nc酸em未e重n组t 增合，强没有遗传性 两病毒混合培养，一病毒能增强另 一病毒的产量
2020/11/26
(4)complementation互补
2020/11/26
2020/11/26
国际病毒分类委员会ICTV
• By 2001 --66 families科, 9 subfamilies亚科 --244 genera属
※ Apparent infection 显性感染
Viruses multiply in host cells and cause clinical symptoms. ✓ Acute infection 急性病毒感染: short incubation, sudden onset, and short duration of disease
2020/11/26
I. tract of viral infection 感染途径
– Respiratory tract 痰、唾液、飞沫、气溶胶 – Alimentary tract 饮水、食物 – Skin 动物咬伤、昆虫叮咬 – Blood 输血、注射、针刺、器官移植 – Genital tract 性交 – Urinary tract 洗浴 – placenta, birth canal 孕期、分娩
• Variation变异: After virus replicates , the characters on the progeny virus are different with the previous g202e0/11n/26eration.
一、 Variation mechanism 病毒变异的机
e.g., HAV, HBV, HCV, HDV, HEV, etc hepatitis.
b. A particular virus may cause several different diseases or no observable引人注意的 symptoms.
e.g., HSV单纯疱疹病毒-1pharyngitis咽炎, herpes labialis 唇疱疹，genital herpes生殖道疱疹, encephalitis脑炎, keratoconjunctivitis角膜结膜炎.
• transcapsidation核壳转移： 无包膜病毒发生的表型混合
2020/11/26
(2)genotype mixing 基因型混 合
• Genome A + genome B → same capsid 衣壳
• Capsid A + capsid B → same envelope 包膜
symptoms or causing mild symptoms.
Significance: important source of infection; 重要传染源 acquire immunity; 获得免疫力 misdiagnose or fail to diagnose;易误诊和漏
诊
2020/11/26