? ? ? virology

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? ? ?virology
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• 3000BC,?????????????????

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??virus

• ??,???????,
• ???????? ????,????????

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?????????

• ???
• ???
• ????
• ???????

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?23? ???????

• ??? ????????
• (Size and Shape )

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???(virion)

• ?????????,?????????,??????

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???????(nm,1/1000?m) lt50 nm
???? (HAV) 50 nm -150 nm ????(influenza
virus) gt 150nm ????(??300
nm)
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A???????? ( 65 95nm )
???? 450nm
??? 390nm
B???? (70nm )
C???????? (30nm )
G
A
???? (1000nm)
D????? ( 40nm )
F
???? 300250nm
E????? (10nm )
B
E
C
F????? ( 100nm )
D
G???????
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????????
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????????
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Viral core (?????)

• The viral nucleic acid genome,In the center of
  the virion,
• Function Control the viral heredity and
  variation, responsible for the infectivity
• The genome of a virus can be either DNA or RNA

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Viral Capsid(?????)

• The protein shell, or coat, that encloses the
  nucleic acid genome.
• Functions
• a. Protect the viral nucleic acid.
• b. Participate in the viral infection.
• c. Share the antigenicity

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Nucleocapsid (???)

• The core of a virus particle consisting of the
  genome plus the capsid

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• ????????Symmetry of Nucleocapsid
• ?????(Helical Symmetry)
• ?????????( Icosahedral
• 
  Symmetry )
• ???? ?(Complex Symmetry )

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RNA
Capsomere(??)
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Envelope(??)

• A lipid-containing membrane that surrounds some
  viral particles.
• It is acquired during viral maturation by a
  budding process through a cellular membrane,
• Not all viruses have the envelope, and viruses
  can be divided into 2 kinds enveloped virus and
  naked virus

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Peplomere(????) spike(??)
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Functions of envelope

• A.Antigenicity
• some viruses possess neuraminidase
• B.Infectivity
• C.Resistance

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• ???? ????genome ??????????
• 
  ???
• ??capsomere ? ??capsid ??????????
• ??envelope,????peplomere(??spike) ??
• 
  ????????

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????????
????
????
??
??
??
???
??(???)
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CHEMICAL COMPOSITION OF VIRUSES(???????)

• Viral Protein
• Viral Nucleic Acid
• Viral Lipids
• Viral carbohydrate

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Viral Nucleic Acid

• DNA-double stranded (ds) linear or circular
• Single stranded (ss) linear or
  circular
• RNA-sssegmented or non-segmented
• sspolarity(sense) or polarity
  (non-sense)
• ds linear (only reovirusfamily)

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Viral Protein

• ????(Structural protein)Capsomere,matrix(??)
  ,glycoproteins on envelope
• ?????--Enzyme ?

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??? ????????(Culture and Replication of Viruses)
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???????????

• ??(Animals)??
• ??(Embryonated eggs)??
• ????(Organ and tissue culture)
• Organ culture
• Cell culture????
• ????
• ?????

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???????
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• ????(Cytopathic effect, CPE)
• ???(Inclusion Bodies)

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????
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CPE
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???????(Negri body)
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????????
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??????????
1?????
?????????,????????,???,?????????????????,?
??????,???????????????????????PFU( plaque forming
units )????

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2?ID50 ? TCID50

• ?????????????,?? 50 ????????????

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?????

• ???
• ????
• ??( replication)
• ??????
• ???????,?DNA????RNA????,?????????????,????????????
  ?,??????????

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Replication of viruses (?????)

• Replicative cycle
• As obligate intracellular parasites, Virus must
  enter and replicate in living cells in order to
  reproducethemselves. This growth
  cycleinvolves specific attachment of virus,
  penetration and uncoating, biosynthesis and
  assembly of the virions and their subsequent
  release from the cell by budding or lysis

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• ?????adsorption and penetration
• ??uncoating
• ????biosynthesis
• ???????assembly and release

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HIV
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???????
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Adsorption and Penetration

• ???????????(????????????????)
• ??

??---????? ??---?????
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uncoating
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Biosynthesislatent period(???)
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• 6?????DNA??
• ??DNA??
• ???RNA??
• ???RNA??
• ??RNA??
• ?????
• ??DNA?? ??(????)
• RNA?? ??(??????
• 
  ??????)

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????(?dsDNA??)

• ??DNA mRNA ????(?)
• 
  (????)
• ??DNA ??mRNA ????
• 
  (????)
• ????

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RNA???????

• ???RNA mRNA ????????
• ????? ????
• ???RNA ?? RNA ???
• ????? ????
• (??RNA?RNA???)

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?????

• ??RNA ???? RNADNA??? ??DNA
  ???????? ????mRNA?????

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assembly and release
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??(assembly)
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??(release)

• ??(Disintegration) naked virus cause the host
  cell lysis
• ??(Budding) enveloped viruses

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???????
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Virus????,????,?????????,????????????????????????
???
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???????????

• ????interference
• ??????????????,????????????? ???????????
• ????
• ???interferon,IFN
• ???????????????????????????????mRNA???

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?????????

• ????( defective virus ) ??????????
• ??????(defective interfering particles, DIP)
• ????????,??????????????
• ???
• ????(?????)(abortive infection)
• ???????,???????????
• ????? ??????

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??? ????????

• ?????
• ?????

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• ???mutant
• ???????(temperature sensitive,ts)
• 2835?????, 3740?????

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?????

• ???????
• ??????????
• ?????????
• ???????????
• ???????
• ??????????????????

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??? ????? (Classification of Viruses)
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????Basis of Classification

• ???????(RNA/DNA, ds/ss, linear/circular, fragment
  /no-fragment))
• ????????
• ???????
• ???????

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• DNA??
• RNA??
• DNA ?RNA ?????

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DNA and RNA Viruses

• ??DNA???(Hepadnasviridae)
• ??????( Retroviridae )

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???( Viroids)

• ?? (200-400nt),?? RNA ??,?????
• ??????
• ?????,???????
• ????????

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????satellites

• ??1 ?RNA?? ,500-2000bp
• 2 ????????
• 3 ???????????
• 4 ???????????
• ??????????????
• ????????RNA??

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???????????