RNA Viruses 2, Microbiology

Why are negative strand RNA viruses referred to as such?
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What does the HA glycoprotein bind to?-cell surface receptorsWhat is the role of the NA glycoprotein?-removes terminal sialic acid residues from oligosaccharides on cell surface proteins and glycolipidsWhy is this important?-important for ifnectivityWhat is the role of fusion protein?-mediates fusion of viral envelope with cell plasma membrane -mediates cell-to-cell fusionWhat is the role of surface glycoprotein?-has cell receptor binding activityWhat is an important type of orthomyxo virus?-influenza virusWhat surface glycoproteins are found on orthomyxovirus?-HA -NAWhat are some important paramyxoviruses?-sendai -measles -RSVWhat surface glycoproteins are found on sendai virus?-fusion protein -HA -NAWhat surface glycoproteins are found on measles virus?-fusion protein -HAWhat surface glycoproteins are found on respirator syncytial virus?-fusion protein -surface glycoproteinHow does penetration of (-) strand RNA viruses occur? List three methods.-fusion of virus membrane with cell membrane -phagocytosis -receptor-mediated endocytosisWhat occurs as soon as (-) strand RNA viruses release nucleocapsids into the cytoplasm?-RNA synthesisUsing...?-RNA transcriptaseWhat type of RNA synthesis specifically occurs?(-) RNA strands --> (+) RNA strandsThe virion (-) strands serve as a template in what form?-RNP formDescribe this RNP form in a bit more detail.-associated nucleocapside proteins cover the RNAWhat does not serve as a template for transcriptase activity?-naked RNAWhat do the mRNAs of the non-segmented, enveloped, helical RNA viruses have in common?-5' cap -3' poly-A tractEach of these mRNAs yields how many viral polypeptides?-only oneWhere does RNA synthesis for the rhabdo-, paramyxo-, and filoviruses occur?-in the cytoplasmHow is the amount of new viral gene product regulated?-through TRANSCRIPTIONAL control (through the level of abundance of various mRNAs)For orthomyxoviruses, what contains the genetic information of the virus?-eight non-identical, single stranded segments of (-) strand RNAWhat specifically is the template for these RNAs?-RNP (not naked RNA)How many of these segments result in the transcription of one mRNA?-sixHow many of these segments result in the transcription of TWO mRNAs?-twoHow are these four mRNAs produced?-via splicingWhat viruses are found within the orthomyxo group?-influenza A, B, and CWhere does transcription of influenza take place?-within the nucleusWhere do the 5' caps for influenza mRNAs come from?-newly synthesized host mRNAsInfluenza virus: where does virus specific protein synthesis occur?-within the cytoplasmInfluenza virus: where does assembly of influenza nucleocapsids take place?-within the nucleusWhat contains the viral genome of bunya viruses?-three non-identical RNA segmentsWhat contains the viral genome of arena viruses?-two non-identical RNA segmentsLocation of transcription: bunya and arena viruses?-cytoplasm5' caps: bunya and arena viruses?-yes3' tails: bunya and arena viruses?-noOrigin of cap structures: bunya and arena viruses?-stolen from host cell mRNAs in the cytoplasmWhat is notable about the bunya and arena viruses?-several bunya viruses and all arena viruses have genomic RNAs that are ambisenseWhat does this mean?-although their RNAs are functionally negative stranded, they have (+) sense and (-) sense coding capacitiesWhat special functionality are some paramyxoviruses capable of?-editing of viral mRNAsWhy is this beneficial?-provides additional coding capacity for viral proteinsWhat are the members of the filo viridae family?-marburg -ebola virusWhat are the key features of the FILO viruses?-RNA -helical -enveloped - (-) sense -SS -nonsegmentedThe ebola virus undertakes what special mRNA editing process?-virus produces two mRNAs from a single genomic coding regionWhat does this result in?-the synthesis of two viral glycoproteinsWhat are these glycoproteins?-secreted glycoprotein (SGP) -glycoprotein (GP)What secretes SGP?-infected cellRole of SGP?-interacts with immune system -suppresses the immune response -inhibition of neutrophil activationHow are SGP and GP similar?-share the same N-terminal (approximately 300 amino acid residues)Where is GP found?-on the surface of the virionsWhen does maturation of (-) stranded RNA viruses begin?-when newly synthesized viral glycoproteins begin to be incorporated in the cell plasma membraneDoes budding always hurt the cell?-noWhat does it always produce?-profound changes in the cell membraneWhat does inefficient budding lead to?-accumulation of viral RNPsDo bunyaviruses bud from the plasma membrane?-noHow then are they produced?-bud from smooth membrane vesicles associated with the golgi apparatusWhat is the most important rhabdo virus?-rabies virusReservoir and vectors of rhabdo viruses?-wild animals -unvaccinated dogs and catsTransmission: rhabdo viruses?-bite of rabid animal or aerosols in caves harboring rabid batsVaccines: available for rhabdo viruses?-yesWhat type of vaccines?-vaccines for pets, wild animals, and at-risk personnelAntiviral drugs: available for rhabdo viruses?-noWhere does rabies virus replicate?-in muscle at bite siteWhat does rabies virus infect?-peripheral nervesWhere does it eventually travel to?-brainSymptoms of rabies virus?-hydrophobia -seizures -hallucinations -paralysis -deathWhat can prevent disease?-post-exposure immunizationWhy?-due to long incubation periodParamyxo virus causes disease that impacts what part of the respiratory tract?-upper respiratory tractWhat two systemic diseases does paramyxo virus cause?-measles -mumpsList the most important paramyxo viruses?-para-influenza -respiratory syncytial -mumps -measles -metapneumovirusTransmission: measles?-large droplet aerosolsVaccine available: measles?-yesWhat type?-live, attenuatedAnti-viral drugs available: measles?-noComplications of measles?-otitis media -croup -bronchopneumonia -enceophalitis -subacute sclerosing panencephalitisHow is measles transmitted?-respiratory secretionsWhat cells does measles initially infect?-epithelial cells of the respiratory tractHow does it spread?-lymphocytes -viremiaWhat can cause rash with measles?-T cell response to virus-infected capillary endothelial cellsWhat is required to control the infection?-cell-mediated immunityTransmission: mumps virus?-inhalation of large-droplet aerosolsVaccine available: mumps?-yesAntiviral drugs available: mumps?-noWhat does the mumps virus initially infect?-epithelial cells of the respiratory tractWhere does the mumps virus replicate?-salivary glands -testes -respiratory tact -CNSWhat is required to control infection?-cell mediated immunityTransmission: respiratory syncytial virus?-large-droplet aerosolsVaccine available: respiratory syncytial virus?-noAntiviral drugs available: respiratory syncytial virus?-yesWhat type of antivirals area available?-ribavarin for infantsDoes respiratory syncytial virus spread systemically?-noComplicating symptoms: respiratory syncytial virus?-bronchitis -febrile rhinitis -pharyngitis -common cold -pneumoniaWhat probably causes bronchiolitis with respiratory syncytial virus?-host immune responseAre infants protected from infection from respiratory syncytial virus by maternal Ab?-noWhat two viruses cause hemorrhagic fever?-ebola -marburgWhat family do these two belong to?-filo virusesTransmission: filo viruses.-contact with infected monkeys -contact with infected humansVaccine available: filo viruses?-noAnti-viral available: filo viruses?-noThe filo viruses cause necrosis of what organs?-liver -spleen -lymph nodes -lungsWhat can lead to death in these disease?-edema -shockWhat unique gene is found within filo viruses?-VP35What is the role of VP35?-RNA polymerase co-factor that inhibits the induction of anti-viral genesIncluding...?-interferon-betaSymptoms specifically of ebola virus?-fever -severe HA -muscle pain -weakness -diarrhea -vomiting -abdominal pain -hemorrhageWhen can symptoms first appear after infection?-2 to 21 daysAverage appearance of symptoms?-8 to 10 dyasWhat does recovery from ebola depend upon?-supportive clinical care -patient's immune responseAb developed by those that recover from Ebola can last for how long?-10 yearsHow is ebola virus transmitted?-direct contact with: 1. blood and body fluids of patient with ebola 2. objects contaminated with the virus 3. infected animalsIs there any evidence that mosquitos or other insects can transmit ebola?-noCan other mammals become infected with the ebola virus?-yesCan measles be transmitted by a blood-borne route?-noMost important orthomyxoviruses?-influenza A, B, nd CSymptoms of influenza?-respiratory tract infection -fever -malaise -sore throat -coughComplications of influenza?-primary viral pneumonia -myositis, cardiac involvement -guillain-barre syndrome -encephalopathy -encephalitis -reye's syndromeMode of transmission: influenza.-small aerosol dropletsWhat two types of vaccine are available against influenza A and B?-killed vaccine -live, attenuatedWhat causes the symptoms associated with influenza virus?-cytokine response to infectionWhat are important for protection against infection?-Ab against hemagglutinin and neuramindiaseWhat does recovery depend upon?-interferon and cell-mediated immune resposeWhat does segmentation of a genome allow for?-random assortment in mixed infectionsWhat causes influenza pandemics every 15 years?-antigenic shiftWhat causes yearly influenza epidemics?-antigenic driftMOA: amantadine and rimantidine?-inhibit uncoatingWhat two important surface glycoproteins are found on ifnluenza?-HA -NAWhat is the major surface epitope seen by the immune system?-HAWhat is the role of HA?-attachment of virus to surface of cellWhat specifically does HA attach to?-sialyloglycoproteins or sialyloglycolipidsWhat is the role of NA?-removes receptors form HA, itself, and from the surface of an infected cellWhat is the impact?-prevents aggregation -facilitates release of virions from cellWhen is NA thought to function?-at the end of a cycle during exit from teh cellWhat might NA cleave to facilitate movement of the attached particle to the cell surface during entry?-HAWhat specifically is responsible for genetic variation and epidemics?-point mutations in HA, and to a minor extend, NAThe influenza transcription apparatus is responsible for ______-stealing.The influenza transcription apparatus is responsible for CAP-stealing.What provides a primer for chain elongation by viral RNA-dependent RNA polymerase?-influenza nuclease cleavage of cellular mRNAsWhat does the virus need to allow for initiation of influenza transcription?-constant supply of newly-synthesized capped mRNAs in the nucleus of infected cellsWhere does assembly of influenza nucleocapsids occur?-within the nucleusWhere is the influenza envelope assembled?-at the plasma-membrane surfaceWhat do the two spliced influenza segments produce?-M1 and M2 -NS1 and NS2What is M1?-matrix proteinWhat is M2?-ion channelWhat is NS1?-non-structural protein that inhibits host immune response and mRNA maturation/nuclear exportWhat is NS2?-facilitates viral RNP export from the nucleusWhat are the most important members of the bunya virus family?-california encephalitis -la crosse virus -hanta/sin nombre virusWhat are the hanta viruses associated with?-hemorrhagic fever -renal syndromeWhat novel hanta virus was associated with an outbreak of acute respiratory illness in 1993?-sin nombre virusReservoir: hanta virus in the US?-rodent populationsHow does transmission of hanta virus to humans occur?-via contact with rodent excretaTransmission: bunya virus?-arthropod bite -rodent exretaVaccines available: bunya virus?-noAnti-viral drugs available: bunya virus?-noIs there any arthropod vector for hanta viruses?-noHosts of hanta viruses?-rodent hostsTransmission: hanta viruses?-aerosolization of rodent excretaMost frequent symptoms of hanta viruses?-fever -myalgia -nausea/vomiting -coughOther symptoms of hanta viruses?-dizziness -arthralgia -SOBRare symptoms?-rhinorrhea -sore throatHosts: sin nombre virus?-vertebrate hostsStructural proteins: sin nombre virus?-G1 -G2 -NCan flu be transmitted by exposure to rodent excreta?-noWhat are the two most important arena viruses?-lymphocytic choriomeningitis virus -lassa virusWhat disease does lassa virus cause?-lassa feverSymptoms of lassa fever?-systemic illness -increased vascular permeability -shockTransmission: arena viruses?-contact with infected rodents or their secrections -body fluidsVaccines available: arena viruses.-noAnti-viral drugs available: arena viruses?-yesWhat ARV is available?-ribavirinHow many genes are found on each arena virus RNA segement?-2How many proteins in total does arena virus RNA code for?-5 proteinsHow can arena viruses be inactivated?-heating to 56 degrees F -low or high pH -UV/gamma radiation -detergentsAll (-) stranded RNA viruses share what symmetry?-helicalWhat protein do all (-) stranded RNA viruses carry?-viral transcriptase (RNA-dependent RNA polymerase)What is the transcription template for all (-) stranded RNA viruses?-RNP complexWhat (-) stranded RNA viruses have non-segmented genomes?-rhabdovirues -paramyxoviruses -filovirusesWhat do some non-segmented (-) stranded RNA viruses utilize to increase coding capacity?-RNA editingWhat are the segmented (-) stranded RNA viruses?-orthomyxo viruses -bunya viruses -arena viruses