Viruses Flashcards
Mechanism of herpes simplex virus down regulating host-cell gene expression
Express VHS gene that causes degradation of host mRNA
Blocks mRNA splicing of most host cell mRNA (until splicing is needed for itself)
Mechanism of picornavirus down regulating host-cell gene expression
Lacks 5’ cap but has internal ribosome entry site (IRES) on 5’ end to allow for translation
Encodes a protein that degrades host cell 5’ cap binding proteins
Two virus families that assemble via pre-formed capsid
Herpesviruses
Reoviruses
Outline of poliovirus replication
Injection of poliovirus DNA through cell membrane
Translation of + RNA into polyprotein that gets cleaved
Cell lyses to release progeny viruses
Rank the genome sizes of the following viruses from smallest to largest: Hep B, human cytomegalovirus, coronavirus, picornavirus
SMALL Hep B Picornavirus Coronavirus Human cytomegalovirus LARGE
Outline of herpes simplex virus replication
Virus attachment to host cell via glycoproteins on cell surface (recognize two receptors on host cell)
Virus and cell membrane fuse, introducing nucleocapsid to cytosol
Virus travels to nuclear pore to release DNA into nucleoplasm
Capsid packaged in nucleus, further modified in cytoplasm (has two membranes) and one membrane is lost when exocytosed from cell
Four types of viruses transmitted by insect vectors
Alphaviruses
Bunyaviruses
Flaviviruses
Reoviruses
Three types of viruses that infect skin due to mechanical abrasion
Papillomaviruses
Poxviruses
Herpes simplex viruses
Pathogenesis of poliovirus that leads to paralysis
Poliovirus is an enteric picornavirus that enters through the GI tract
Replication in GI tract but spreads hematogenously (acute viremia)
Spreads to CNS where infection can result in paralysis
Dengue virus vs immune system
Antibody against virus increases opsonization which allows viral entry into macrophages where infection is established
Classification, nucleic acid, and, cells infected, major structural properties of Ebola virus
Member of filovirus family
Minus sense ssRNA genome
Infects macrophages, monocytes, liver cells, and vascular endothelial cells
Coated by N-protein, helical ribonucleotides, membrane made of G-protein molecules which forms spikes which facilitates virus entry into host cells
Zanamivir and Oseltamivir
Anti-influenza drugs
Neuraminidase inhibitors: inhibits spread of infectious progeny virus from infected cell
Substrate of neuraminidase is sialic acid, these drugs mimic sialic acid
Amantadine and Rimatadine
Anti-influenza drugs
Inhibit influenza virus uncoating by blocking proton channel function of viral M2 ion channel
Effective against influenza A strain but recently, widespread resistance is spreading
