A virus which, upon infection of a host , does not necessarily cause lysis but whose genome may replicate in synchrony with that of the host
Germen measles Group: Group IV ( (+)ssRNA ) Family: Picornaviridae Genus: Enterovirus Species: Poliovirus Group: Group IV ( (+)ssRNA ) Order: Picornavirales Family: Picornaviridae Genus : Rhinovirus Group: Group V ( (-)ssRNA ) Family: Orthomyxoviridae Genera Influenzavirus A Influenzavirus B Influenzavirus C Group: Group IV ( (+)ssRNA ) Family: Flaviviridae Genus: Flavivirus Species: Tick-borne meningoencephalitis virus Group: Group IV ( (+)ssRNA ) Family: Togaviridae Genus: Rubivirus Species: Rubella virus Group: Group V ( (-)ssRNA ) Order: Mononegavirales Family: Paramyxoviridae Genus: Rubulavirus Type species Mumps virus Group: Group V ( (-)ssRNA ) Order: Mononegavirales Family: Paramyxoviridae Genera Subfamily Paramyxovirinae Avulavirus Henipavirus Morbillivirus Respirovirus Rubulavirus Subfamily Pneumovirinae Pneumovirus Metapneumovirus Group: Group V ( (-)ssRNA ) Order: Mononegavirales Family: Rhabdoviridae Genus: Lyssavirus Species: Rabies Group: Group VI ( ssRNA-RT ) Family: Retroviridae Genus: Lentivirus Species Human immunodeficiency virus 1 Human immunodeficiency virus 2
Group: Group I ( dsDNA ) Family: Adenoviridae Genera Atadenovirus Aviadenovirus Ichtadenovirus Mastadenovirus Siadenovirus Group: Group I ( dsDNA ) Family: Herpesviridae Subfamily: Alphaherpesvirinae Genus: Simplexvirus Species Herpes simplex virus 1 (HWJ-1) Herpes simplex virus 2 (HWJ-2) Group: Group I (dsDNA) Family: Herpesviridae Subfamily: Gammaherpesvirinae Genus: Lymphocryptovirus Species: Human herpesvirus 4 Variola virus (Smallpox) Virus classification Group: Group I (dsDNA) Family: Poxviridae Genus: Orthopoxvirus S pecies: Variola vera Group: Group I (dsDNA) Order: Unranked Family: Papillomaviridae
virus classification• host specification: plant, animal, bacteria• DNA a RNA virus: ds DNA, ss DNA, ds RNA, pos ss RNA, neg ss RNA, rev trans diploid ss RNA, rev trans circular dsDNA• structure: symmetry helical, complex, icosahedral, capsid, envelope, number of capsomer
ds DNA, ss DNA, ds RNA, ss RNA, rev trans diploid ss RNA, rev trans circular dsDNA
Reverse transcriptase = enzyme overwriting RNA to DNA transcriptionreplication reverse transcription translation RNA Protein DNA
Viruses can reproduce only within a host cell• Obligate intracellular parasites• lack enzymes and ribosomes …• only a limited range of host cells– host specificity• eukaryotic virusesare tissue specific• Lytic cycle – virulent viruses
Lytic cycle of virus reproduction• adsorption virus to cell• penetration virus or viral NA into cell• replication, transcription and translation•assembling new virus particles (self-assembly)• transfer to daughter cells: effect on the cell:death of the cell – lyses (hundreds or thousand) cytopathy effect (exocytose)
Lysogenic - virogenic cycle= integration of the viral nucleic acid into the host genome as provirus (prophage)• replication with the DNA of the host cell• latent viruses – the cell is not damaged• virus is transferred to daughter cells• viruses as vectors of oncogeny
Tumor viruses - transformation of eukaryotic cellsto cancer cellsDNA viruses – oncogeneRNA viruses= retroviruses
Prions• degeneration brain disease• infectious particles• contain proteins, NA wasn‘t proved• abnormal prion = product of mutated genes
Prion protein- occurrence in two isoforms: normal PrPC (C=cellular) abnormal PrPSC (SC=scrapie)– PrPC – prevalence of alpha helix a little beta structure– PrPSC – prevalence of beta structure– presence of PrPSC induces PrPC change = normal protein to abnormal - runs as chain
• hereditary disease= gene mutation → abnormal protein• transfer between species is rare, but might be possible with a long period of latency• transfer from human to human: by growth hormone, brain electrodes
DiseaseThey cause an infection in sheepcalled scrapie and cattlebovine spongiform encephalopathy("mad cow" disease).
Human diseases– Creutzfeld-Jacob disease: affection of the grey brain cortex, severe neurological symptoms with quickly proceeded dementia)– kuru: Papua-New Guinea: disability of movement coordination, paralysis, dementia – disease is extension by ritual cannibalism
Neural degeneration in aprion infection.a slice from the brain of aperson who died of kuruThe large fluid-filled holesare places where neuronshave died.