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Prof. Mamdoh Harahsha. B.Sc: Biology / Medical Analysis / Jor. M.Sc.: Medical Microbiology / Jor. Ph.D.: Medical Virology & Serology / UK. GENERAL PROPERTIES AND CLASSIFICATIONS. INTRODUCTION. Small Dependent on living cells Genome Have receptor-binding protein. Virus. Bacterium. - PowerPoint PPT Presentation
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B.Sc: Biology / Medical Analysis /
Jor. M.Sc.: Medical Microbiology / Jor. Ph.D.: Medical Virology & Serology /
UK
Prof. Mamdoh Harahsha
INTRODUCTIONINTRODUCTION
• SmallSmall
• Dependent on living cellsDependent on living cells
• GenomeGenome
• Have receptor-binding proteinHave receptor-binding protein
Comparing the size of a virus, a Comparing the size of a virus, a bacterium, and an animal cellbacterium, and an animal cell
0.25 m
Virus
Animalcell
Bacterium
Animal cell nucleus
Size of virusesSize of viruses
Basic components of virusesBasic components of viruses
Virion (Intact virus):Virion (Intact virus):
• Capsid (capsomeres)Capsid (capsomeres)
• Nucleic acidNucleic acid
Both Both Nucleocapsid Nucleocapsid
# Envelope# Envelope
Influenza virusInfluenza virus
Virus symmetry Virus symmetry (Nucleocapsid)(Nucleocapsid)
• IcosahedralIcosahedral
• HelicalHelical
• ComplexComplex
Capsid and CapsomeresCapsid and Capsomeres
Helical Helical
IcosahedralIcosahedral
ComplexComplex
Electron MicroscopyElectron Microscopy
Virus Virus genomesgenomes
• # All DNA viruses ds # All DNA viruses ds EXCEPTEXCEPT
ParvoviridaeParvoviridae
• # All RNA viruses ss # All RNA viruses ss EXCEPTEXCEPT
ReoviridaeReoviridae
• # Positive & Negative stranded RNA# Positive & Negative stranded RNA
• # Exons & introns# Exons & introns
Virus genome & transcriptional Virus genome & transcriptional mapsmapsDNA virusesDNA viruses
• Herpes & PoxvirusHerpes & Poxvirus
150 genes 150 genes No splicing No splicing
(Large No. of genes)(Large No. of genes)
• AdenovirusAdenovirus
30 genes 30 genes Viral Viral splicing splicing
• ParvovirusParvovirus
Few genes Few genes Viral Viral splicingsplicing
RNA virusesRNA viruses
• Poliovirus: Poliovirus: +ve ssRNA+ve ssRNA
• Rabies: Rabies: -ve ssRNA-ve ssRNA
• Coronavirus: Coronavirus: +ve ssRNA+ve ssRNA
Classification of VirusesClassification of Viruses
• NA: NA: DNA OR RNADNA OR RNA• Number of strands of NA: Number of strands of NA: ds ds
or ss, or ss, • Forms: Linear, Circular, Forms: Linear, Circular,
Continuous (or circular with Continuous (or circular with breaks as in HBV), or Segmentedbreaks as in HBV), or Segmented
• PolarityPolarity• Symmetry of NASymmetry of NA• EnvelopeEnvelope
Nomenclature of virusesNomenclature of viruses
• Family:Family: --- viridae --- viridae
((AdenoviridiaeAdenoviridiae))
• SubfamilySubfamily --- Virinae--- Virinae
((AdenovirinaeAdenovirinae))
• Genera: Genera: --- virus--- virus(Adenovirus)(Adenovirus)
• Serotype: Serotype: --- Nnumber or letter--- Nnumber or letter
DNA VIRUSESDNA VIRUSES
• Poxvirus:Poxvirus: (Pox : pock or pustule)(Pox : pock or pustule)
• Herpesvirus:Herpesvirus: (Herpes : creeping)(Herpes : creeping)
• Adenovirus:Adenovirus: (Adeno : gland)(Adeno : gland)
• Hepadnavirus: Hepadnavirus: (Hepa : liver, dna: DNA)(Hepa : liver, dna: DNA)
• Papovavirus:Papovavirus: (Pa: papilloma, (Pa: papilloma,
Po: polyoma, Va: vacuolating Po: polyoma, Va: vacuolating agent)agent)
• Parvovirus: Parvovirus: (Parvus: small)(Parvus: small)
RNA VIRUSESRNA VIRUSES• Orthomyxovirus, paramyxovirusOrthomyxovirus, paramyxovirus
(Myxo: mucus)(Myxo: mucus)
• Rhabdovirus: Rhabdovirus: (Rhabdos: rod)(Rhabdos: rod)
• Picornavirus:Picornavirus: (Pico: small, (Pico: small, rna:rna:
RNA)RNA)
• Togavirus: Togavirus: (Toga: cloak)(Toga: cloak)
• Flavivirus: Flavivirus: (Flavi: yellow)(Flavi: yellow)
• Reovirus: Reovirus: (R: respiratory, E: (R: respiratory, E:
enteric, O: orphan)enteric, O: orphan)
• Arenavirus: Arenavirus: (Arena: sand)(Arena: sand)
• Retrovirus: Retrovirus: (Re: reverse, (Re: reverse, TR: TR: transcriptase)transcriptase)
• Calicivirus: Calicivirus: (Calix: cup)(Calix: cup)
• Coronavirus: Coronavirus: (Corona: Crown)(Corona: Crown)
Morphology of VirusesMorphology 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
RNA viruses
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
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
RNA viruses
Astroviridae 30 I
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