Please enable JavaScript.
Coggle requires JavaScript to display documents.
Viruses - Coggle Diagram
Viruses
Different viruses
Zoonotic-Either Sylvatic-(reservoir)monkey>mosquito>humans
or Urban cycle- Mosquitos transmit from human to human
Ex Yellow Jacket fever flavivirus ss RNA envelope first disease found to be caused by virus 1901 walter reed no specific treatment there is a vaccine attenuated yellow fever 17D strain or Dakar stain
Animal viruses-attach to plasma membrane proteins and glycoproteins enter by pinocytosis or fusion uncoating digestion of protein coat lysosomal enzymes
DNA viruses-occurs in nucleus (except in POX virus bc too big) capsid and proteins synth in cytoplasm and transported to nucleus for assembly
Retrovirus RNA viruses (HIV) carry reverse transcriptase virus RNA->DNA->RNA->protein provirus virus DNA stay in chromosome of cell and stay latent but can cause cancer higher chance every time reinfected
Influenza
Family-Orthomyxoviridae Genus-Influenzavirus Capsid-protein coat Envelope- lipid bilayer genome-8 separate RNA segmants has spikes Neuramindase (separate) and Hemagglutinin (attach)
A-regular outbreaks infect animals
B-causes sporadic outbreaks lim area
C-common seldom causes disease symptoms(mild)
annual vaccine injected or nasal vaccine is adjusted each year to accommodate antigenic drift/shift
TMT neuraminidase inhibitors decrease length
Spanish flu pandemic 1918-showed an avian H1N1virus with 10 changes in a.a became endemic in swine originated in swine in kansas killed 67500 people in USA 20-50mil world people were dead within hours it caused hemorrhagic viral pneumonia
Morphology
Polyhedral virus-Icosahedron 20 equilateral triangles-Expoliovirus(ssRNA), Adenovirus(dsDNA,spikes)
Helical virus-exFiloviridae(ebola ssRNA), Rhabdovirda lyssavirus (Rabies ssRNA)
-
Complex dsDNA, enveloped, large e T-bacteriophage
History
Adolf Mayer-1886 demo TMD can be transmitted plant to plant
Dimitri Iwanoski- 1892filtered sap through filter-filterable agent (pass through 0.2U)
Wendell Stanley- 1930 Isolated TMV and electron microscope invented
Lytic cycle-T4fage virulent phage-ends in death of host cell
virus infect cell inplant DNA biosynthesis cell produce parts of virus maturation components assembled release host cell lyses
Lysogenic-Lambda phage template phage-host cell remain alive
insert DNA into host genome(prophage) then phage remains latent host cells are called lysogenic cells which are immune to reinfection
phage conversion-the host may exhibit new properties
ex corynebacterium diphtheria produces diseas diphtheria only when prophage is present bc it codes for the cytotoxin
-
Viral structure
External- Capsid-protein coat surrounding core
Envelope-surround capsid part of cell membrane and proteins virus coded for
Nonenveloped virus- only nucleic acid and capsid
Spikes-carbs and protein complexes-help attach-virulence-can identify a virus
Internal-Virion complete fully developed virus nucleic acid and protein coat
some have ssDNA(few) dsDNA(many) ssRNA(many) dsRNA(few)
Antigenic Shift
-
Previus antibodies will no longer work to fight this infection and pandemics occur when the viruses acquire these new H or N spikes
Antigenic Drift
minor annual variations in antigenic makeup of virus often alteration in a single a.a of the HorN spike - high mutation rates =characteristic of RNA virus
Vaccine production
Scientists try to guess new strain of circulating virus it takes months to develop vaccine it is 70-90% effective