Download GENERAL PROPERTIES AND CLASSIFICATION S

Prof. Mamdoh Harahsha
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B.Sc: Biology / Medical Analysis / Jor.
M.Sc.: Medical Microbiology / Jor.
Ph.D.: Medical Virology & Serology / UK
INTRODUCTION
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Small
Dependent on living cells
Genome
Have receptor-binding protein
Comparing the size of a virus, a bacterium,
and an animal cell
Virus
Bacterium
Animal
cell
Animal cell nucleus
0.25 m
Size of viruses
Basic components of viruses
Virion (Intact virus):
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Capsid (capsomeres)
Nucleic acid
Both  Nucleocapsid
# Envelope
Influenza virus
Virus symmetry (Nucleocapsid)
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Icosahedral
Helical
Complex
Capsid and Capsomeres
Helical
Icosahedral
Complex
Electron Microscopy
Virus genomes
• # All DNA viruses ds EXCEPT
Parvoviridae
• # All RNA viruses ss EXCEPT
Reoviridae
• # Positive & Negative stranded RNA
• # Exons & introns
Virus genome & transcriptional maps
DNA viruses
• Herpes & Poxvirus
150 genes  No splicing
(Large No. of genes)
• Adenovirus
30 genes  Viral splicing
• Parvovirus
Few genes  Viral splicing
RNA viruses
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Poliovirus:
Rabies:
Coronavirus:
+ve ssRNA
-ve ssRNA
+ve ssRNA
Classification of Viruses
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NA: DNA OR RNA
Number of strands of NA:
ds
or ss,
Forms: Linear, Circular, Continuous
(or circular with breaks as in HBV),
or Segmented
Polarity
Symmetry of NA
Envelope
Nomenclature of viruses
• Family:
--- viridae
(Adenoviridiae)
• Subfamily
--- Virinae
• Genera:
--- virus
• Serotype:
(Adenovirinae)
(Adenovirus)
--- Nnumber or letter
DNA VIRUSES
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Poxvirus:
(Pox : pock or pustule)
Herpesvirus:
(Herpes : creeping)
Adenovirus:
(Adeno : gland)
Hepadnavirus:
(Hepa : liver, dna: DNA)
Papovavirus:
(Pa: papilloma,
Po: polyoma, Va: vacuolating agent)
Parvovirus:
(Parvus: small)
RNA VIRUSES
• Orthomyxovirus, paramyxovirus
• Rhabdovirus:
• Picornavirus:
• Togavirus:
• Flavivirus:
(Myxo: mucus)
(Rhabdos: rod)
(Pico: small, rna:
RNA)
(Toga: cloak)
(Flavi: yellow)
• Reovirus:
• Arenavirus:
• Retrovirus:
• Calicivirus:
• Coronavirus:
(R: respiratory, E:
enteric, O: orphan)
(Arena: sand)
(Re: reverse,
TR: transcriptase)
(Calix: cup)
(Corona: Crown)
Morphology of Viruses
Family name
Genome
Positive or
negative stranded
genome
Infectivity of isolated
nucleic acid
Polymerase or transcriptase
present in virion
Approx. genome
size
DNA viruses
Parvoviridae
ss
+-
+
None
5
Papovairidae
ds
+-
+
None
8
Adenoviridae
ds
+-
+
None
36
Herpesviridae
ds
+-
+
None
150
Poxviridae
ds
+-
-
DNA-RNA
150
Hepadnaviridae
ds
+-
?
DNA-RNA
3
Astroviridae
ss
+
+
None
v8
Picornaviridae
ss
+
+
None
8
Flaviviridae
ss
+
+
None
10
Togaviridae
ss
+
+
None
12
Coronaviridae
ss
+
+
None
30
Bunyaviridae
ss
-
-
RNA-RNA
16
Orthomyxoviridae
ss
-
-
RNA-RNA
13
Paramyxoviridae
ss
-
-
RNA-RNA
15
Rhabdoviridae
ss
-
-
RNA-RNA
15
Arenaviridae
ss
-
-
RNA-RNA
12
Retroviridae
ss
+
-
RNA-DNA
10
Reoviridae
ds
-
-
RNA-RNA
20
Filoviridae
ss
-
-
RNA-RNA
12
Caliciviridae
ss
+
?
None
8
RNA viruses
Family name
Representative viruses
Approximate diameter of
virion (nm)
Symmetry of of nucleocapsid
DNA viruses
Parvoviridae
Human parvovirus
20
I
Papovaviridae
Wart viruses
50
I
Adenoviridae
Adenoviruses
80
I
Herpesviridae
Herpes simplex viruses
180
I
Poxviridae
Vaccinia virus
250
C
Hepadnaviridae
Hepatitis B virus
40
I
30
I
RNA viruses
Astroviridae
Picornaviridae
Polioviruses
25
I
Flaviviridae
Yellow fever virus
30
I
Togaviridae
Rubella virus
80
I
Coronaviridae
Infectious bronchitis virus
100
H
Bunyaviridae
California encephalitis virus
100
H
Orthomyxoviridae
Influenza viruses
100
H
Paramyxoviridae
Measles virus
150
H
Rhabdoviridae
Rabies virus
150
H
Arenaviridae
Lassa fever virus
100
H
Retroviridae
HIV-1
100
I
Reoviridae
Rotaviruses
70
I
Filoviridae
Marburg virus
Variable
H
Caliciviridae
Calicivirus
35
I