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94 Cards in this Set
- Front
- Back
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Definition of Sterilization
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Process that kills or eliminates all types of microorganisms INCLUDING spores but NOT prions
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Definition of Disinfection
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Lower grade process that kills or removes many microorganisms EXCLUDING spores and prions
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What is the most resistant to sterilization/disinfection?
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Spores/Prions
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Sterilization Methods
Heat: Radiation: other Physical method: Chemical methods: |
1. Dry Heat, Moist Heat(autoclave)
2. Ionizing rays(x and gamma) 3. Filtration 4. Glutaraldehyde(cold sterile) 5. Ethlene Oxide(gas sterilization) |
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Autoclave Sterilization:
Methods, 15-20 minute, 3 minute cycles? Kills micros by? |
1. 121C(250F) with Stream Pressure of 15psi for 15-20 minutes
2. 134C(270F) with Stream Pressure of 30 psi for 3 minutes 3. Thermal coagulation of proteins |
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Ethylene oxide Sterilization:
Type of sterilizaton? Temperature? Used for? Kills micros by? |
1. Gas
2. 60C/140F 3. Heat, H2O sensitive objects 4.alkylating agent,dammage proteins and nucleic acids |
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Glutaraldehyde Sterilization:
also known as? Mixture? Kills micros by? |
1. Cold Sterile
2. 2% glutaraldehyde 3. Alkylizing agent |
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Sterilization Assurance
2 ways? |
1. Spore Strip: non-pathos Bacillus species spore which after sterilization will be submerged in a growth medium and incubated
2. Self Contained Spore-only for steam sterilizer, spore strip/disc inside a vial containing growth medium-->incubates after sterilization |
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Chemical Methods of Sterilization:
Most widely used antiseptic? Disinfectant? Denatures proteins and nucleic acids? Cationic detergent which is a disinfectant and antiseptic? |
1. Alcohol
2. Chlorine 3. Formaldehyde 4.Quartenary ammonium |
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Substances used for disinfection?
what do each of them do? |
1. Disinfectants: destroy microorganisms in non-living objects, used on inanimate objects
2. Antiseptics: destroy microorganisms on living tissue, used on viable tissue |
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Pasteurization:
Definition? Trying to achieve? How is milk pastuerized? |
1. Process of heating a liquid, usually milk, to a temperature between 55-70C(131-158F) to destroy harmful bacteria without changing composition/flavor/nutritive value of liquid
2.log reduction of viable organisms-->reduce chances of disease 3. Heating to 63C(145F) for 30 minutes, rapid cooling then store at temp below 10C |
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Structure of Viruses
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1. nucleic acid(RNA/DNA never both), protein(and possbily-lipid, helps protect DNA/RNA).
An EC infectious viral particle is called a virion |
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Intracellular parasitism
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1. Viruses are obligate intracellular parasites that depend on the host cell machinery for replication.
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Virion:
exists where? potential to? size? composed of? |
1. Extracellularly
2. Infect host cells 3. 10nm-400nm 4. Viral Genome(DNA/RNA), Protein Caspid, maybe Cell Envelope |
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Naked Caspid is composed of?
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Nucleocaspid:
DNA/RNA Structural Proteins maybe Enzymes and Nucleic Acid Binding Proteins |
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Enveloped virus is composed of?
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Nucleocapsid + glycoproetin and membrane
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in a nucleocaspid where is the glycoprotein made up of? Where are the origins of it?
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1. Lipid bilayer membrane from host
2. Glycoprotein from virus itself |
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Caspid Symmetry is the most _____ to build a structure
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economical
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Two of the most common forms of capsid symmetry
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Helical
Polyhedral/Spherical: icosahedral symmetry |
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Symmetry for polyhedral/icosahedral/spherical shape
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three fold(side)
five fold(top) 2 fold(any line) |
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What is the importance of having symmetry in the capsid?
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Virus doesn't need large coating capacity and provides an economic way in which the virus can easily repair itself if dammaged.
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the formation of a polyhedral capsid from proteins
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5 protomers(proteins) = 1 pentamer capsomere
12 Pentamers = mature viron |
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A caspid is _____ assembled thus must use ______ because?
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self assembled
minimum free energy host cell has limited free energy |
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similarities between a naked virus and a enveloped one?
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Both consist of basics:
Nucleocaspid=Capsomeres+ Nucleic Acid |
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differences between a naked virus and a enveloped one?
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Enveloped has an envelope with VAP proteins
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Naked Caspid:
Component: Stable to: Released by: |
1. protein
2. heat, acid, proteases, detergents, drying 3. Lysis |
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Naked Caspid + viruclence
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1.Spread Easily(stable) -->fomites, hand to hand, dust, small droplets
2. Survive adverse conditon of GUT 3. Resistant to detergents and poor sweage treament, dry, acid, pH, temp, proteases |
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Naked Caspid - viruclence
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1. Maybe detered by antibodies
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Enveloped Virions:
Components: Stable to: Released by: |
1. Membrane, lipids, proteins, GPs
2. Labile to Acid, Detergents, Drying and Heat, Modified Cell Membrane during replication, needs antibodies and cell mediated to be detered 3. Budding and Lysis |
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Naked Caspid + viruclence
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1. Spreads well-->large droplets, secretions, organ transplants, blood tranfusions
2.Does not need to kill cell to spread 3. Causes hypersensitivity and inflammation to cause immunopathogensis |
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Naked Caspid - virulence
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1. Must stay Wet
2. Cannot survive gi tract 3. Needs antibody/cell mediated immune response for protection and control |
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Hep A outbreak was caused by?
Proves? |
Naked Capsid on Green onions, underwent 3-4 weeks of transport in harsh conditions, proves how resilient naked capsids are.
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Steps in Viral Replication
8 steps |
1. Recognition of target
2.Attachment 3. Penetration 4. Uncoating 5. Macromolecular synthesis 6. Assembly of capsid(DNA-->nucleus, RNA-->cytoplasm) 7. Budding of assembled virus 8. release of virus |
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Attachment and Penetration: Enveloped virions
Attachment method? Penetration is dependent on? |
1. Attachment: VAP binds cellular surface receptors
--->receptor mayjor TROPISM factor --->Cell Receptors are usually glycoproteins Penetration: Energy Dependent pH dependent: endocytosis, direct fusion Translocation directly into cytoplasm |
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Penetration of Capsid Virions
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Penetration via endocytosis which is pH dependent because there is no membrane to fuse...
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Uncoating Strategies
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1. Uncoating at plasma membrane
a. uncoating at PM then docking onto nuclear membrane 2. Uncoating within endosomes, forms endosome first to enter, then uncoats once inside 3. uncoating at nuclear membrane; forms endosome then docks on nuclear membrane where in the uncoats |
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Difference between enveloped and naked uncoating
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Enveloped has membrane which can fuse with membrane
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Single Cylce Growth Curve:
Stages defined by? |
absence/visible viral components-Eclipse-no change
infectious virus in media-latent-no change to some growth macromolecular snythesis-early/late phases-decrease-->no change-->some growth |
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True or False, All viruses grow the same
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False
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Fundamental Properties for Viral Propogation
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1. All viral genome is packaged inside particles that protect and mediate transmission from host to host.
capsid/envelope 2. Virus may use host cells machinery but genome contains ALL information required for initating/completing an infectious cycle within a suscpetible permissive cell 3. all viruses have co-evolved with their host so virus survival is ensured |
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Viral Genomes have..?
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1. Unusual ends
2. Often modified 3. Segmented, multipartite genomes |
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ss/ds:
Viral DNA Viral RNA RNA-->DNA DNA-->RNA |
DNA: ss/ds DNA
RNA: ss/ds RNA RNA-->DNA(retrovriuses): ss RNA DNA-->RNA(hepadnaviruses): ds DNA |
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Nucleic acids maybe blank charged
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positive/negatively
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Most DNA viruses are ____ except for ____
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Double stranded
parvoiridae |
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Most RNA viruses are:
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Single stranded except for reovirdae
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Families of Enveloped Bacteria
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pox, herpes, hepadna
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Families of Naked Capsid
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PAPP
polyoma, papilloma, adeno parvo (ss) |
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Genome Replication:
Small DNA viruses are replicated by? Examples? Large DNA viruses are replicated by? Examples? RNA viruses(including retroviruses) are replicated by? |
Host DNA Polymerase
Papillomaviruses, Polyomaviruses Own Replication machinery hepresviruses, Poxviruses Own Polymerase-cells don't have ability to make DNA from RNA..thus neeed to encode own polymerase |
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Why are small DNA viruses replicated by Host DNA Polymerase instead of own?
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Limited/minimum coding, thus can only have coding for essential proteins.
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General Replication Steps for DNA Virus
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Dance, Bring her Home, Take off Close, Sex, Call her next day, Date, Break up
1. attachment 2. penetrate 3. uncoat 4. gene replication 5. assembly 6. maturation 7. release |
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DNA are ___ compared to RNA
DNA viruses establish ____ infections DNA genomes reside in the ___ except for ____ Viral Gene Transcription is ___regulated. Which genes in DNA encode what? DNA polymerase requre ____ to replicate the viral genome |
not transient or labile
persistent nucleues poxviruses Temporally early genes-DNA binding proteins/enzymes late genes-proteins primer |
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Virulence Factors defintion?
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any virally encoded activity that allows virus to cause disease
ex, replication, transmission, tissue invasion, escape from immune system |
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Attenuation definition?
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loss or reduction of virulence factors of the virus
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Host Factors?
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immune responses to control the infection
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Vaccine are viruses which____
Can be ___ or ____ |
loss of virulence factors and induction of immune responses.
Vaccines can be live viruses(generated by repeated passage of virus in cell lines or genetic engineering) or individual antigens. |
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Permissive cells:
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allow complete replication cycle for virus
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Lysis:
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Death of cell and release of virus
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Persistent Infection
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Cell doesn't die, becomes reservoir for more virus--budding
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Latent Infection
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reverse transcribes into DNA, remains latent until environment is favorable-->start making more(Lytic infection)
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Outcomes of viral infection
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1. Abortive
2. Lytic 3. Persistent |
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Abortive infection
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virus fails to multiple usually due to MUTATION.
cell is permissive but virus has mutation, may fail to multiply due to defect on virus's end |
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Lytic Infection
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Virus production leading to cell death
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Persistent Infection
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infection w/o cell death
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Lytic Infection: Inhibition of?
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protein synthesis, nucleic acid synthesis
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Lytic infection: Direct ___ of viral products
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toxicity
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Lytic infection: Immune attack mediated by what?
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-expression of viral antigens on cell surface for immune attack
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Lytic infection: physical disruption of cell by?
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accumulation of viral particles
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Lytic infection: virus may program ___ using its _____ , the virus also includes ____ to make sure the cell will_______
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Apoptosis, genes
anti-apoptotic genes, will survive long enough to make more progeny |
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Lytic infection: viral cells may cause ____ via ____
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syncytia- cell-to-cell fusion via cell surface viral proteins
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Persistent Infection:
Types? |
chronic: viral production/release which DOES NOT intefere with cellular metabolism. Cell has ABILITY to grow and divde ultimately damage leads to its demise
Latent: not all viral genes expressed, conditions allow expression only expression of some viral genes transforming(immortalizing)-ongensis recurrent |
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Progression of Viral Disease
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1. Acquistion(entry into body)
2. Initiation of infection at primary site 3. incubation period-virus amped and spread to 2ndary site 4. Replication in target tissue-->disease signs 5. Immune Responses: immunopathogensis 6. Contagion- virus in tissue that can be spread 7. Resolution or persistent infection/chronic disease |
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Determinants of Viral Pathogensis
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1.Interaction of virus with target tissue
2.Cytopathologic activity of Virus 3. Host protective responses 4. Immunopathlogy |
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Interaction of Virus with Target Tissue
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1. access to tissue
2. stability of virus in body(temp,pH) 3. Ability to cross skin/mucous epithelial cells 4. Ability to establish viremia(enter blood) 5. Ability to spread through reticulendothelial syste, 6. Target Tissue: Specific viral attachment Tissue-specific expression of receptors |
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Host Immune Responses
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1. Antigen non-specific INNATE
-interferon -NKC, macrophage, dendritic 2. Antigen-specific ADAPTIVE -Tcell CD8(cyto) CD4(help CD8+ Tcells) -Antibodies: neutralizing, complement, antibody dependent |
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Immunopathlogy
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-Interferon-flu like
-Tcell-delayed hypersensitivity -Antibody-complement, antibody-depend. cellular cytotoxicity, immune complexes |
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Innate immune responses to viral infection
Natural Killers cells activated by? target? Mac-D fxn by? INF-a produced by? DC initiate ___ responses? Present blank to CD4 cells? |
NK killers-activated by IFN-a
target virus-infected cells(envelope viruses) Macrophages/Dendritic-INF gamma -filter viral particles in blood -inactivate opsonized virus particles -Immature dendrtic-->INF alpha -DCs initate CD/CD8 response -DC/Macro present antigen to CD4 T cells |
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Mechanisms Viral Evasion:
Hidden from antibody |
Latent infection
Cell-Cell infection-syncytia Antigenic variation Secretion of blocking antigen Decay complement |
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Inhibit immune cell fxns
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Impairment of DC fxn
Impairment of lymphocyte fxn Prevention of CD8 T-cell killing Kills CD4 T-cells and alteration of macrophages Suppression of NK/T/B Immunosuppressive factors |
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Mechanisms for Viral Evasion of Immune Responses
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1. Decreased Antigen presentation
Stop MHC class I -transcription -translocation -surface exp -prevent peptide binding 2. Inhibition of inflammation Inhibit IL-1 -production -action -stop up reg of MHC exp -blcoks 2x RNA activation PKR |
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Transmission:
define: Modes of entry Tropism Dissemination |
1. Mode of entry-wound/mucous membrane-can replicate there
2. Tropism-preference for certain tissues 3. Dissemination-blood, lymphatics |
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Viral Oncogensis:
discoveries via viruses |
1. oncogenes, src ras etc.
2. tumor supressor genes p53/rb |
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Define:
Oncogensis cell transformation oncogene tumor supressor |
1. development of tumors via unctrolled cell rep
2. changes in cells leading to unctrolled replication.(physical, chemical, viral) 3.gene whcih promotes cell proliferation/anti-apoptosis 4. inhibits cell proliferation |
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Virus Induced Neoplasia:
Indirect |
1. Suppression of host immune system, impaired ellmination of tumor cells
2. stim of cell proliferation, increased targets for other neoplastic changes a. tissue regeneration after viral cytolysis b. mitogenesis of immune competent or other cells |
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Virus Induced Neoplasia: Direct
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1. hit and run: no crucial virus gene or structure whose persistence is essential. Viral DNA/Viral Fxns act transiently
2. Crucial part of viral genome persist in tumor cells a. virus varries a gene whose product directly or indirectly initiates and/or maintains neoplasia(oncogene) b. Insertional mutagenesis: virus DNA inserted in the host chromosome augments or destroys normal gene expression. |
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RNA Tumor viruses
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1. animal retroviruses as model systems
2. human t-cell leukemia virus HTLV 1, 2 3. Hep C Virus |
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DNA tumor Viruses
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hep B, polyoma , papilloma, adenovirus, epstein-barr virus, human herpesvirus-8
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Why do viruses cause cancer?
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1. Viral life = replicate, transformation and tumorigensis are 2ndary effects
2. Stimulate cellular proliferation and machineries to replicate its DNA genome. Overdoing --> tumorigensis 3. Parasitization in host evade immune |
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Development of smallpox vaccine how?
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use cowpox less dangerous form to build immunity to small pox.
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Three types of vaccines
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1. live virus(highest risk)
2. inactivated 3. sub-unit vaccine(immunogenicity) |
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New vaccine approaches
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1. genetic engineering of vector and viruses
2. DNA vaccines 3. synthetic peptides |
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Sub-unit Vaccines types + examples, method
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a. synthetic vaccines: noneffect/use
b. Recombinant Vaccines HBV-yeast or CHO cells c. Virus Vectors Use well understood attentuated virus to present antigens. -difficult to produce d. DNA vaccine |
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Inactivated Vaccines
Method? Positives? Downfalls? |
1. Expose virus to denaturing agent to loss antigenicity
+ stable, little risk - not possible for all viruses, dangerous to produce, not as effective as live viruses, short-lived protection |
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Live Virus Vaccines
Method? Positives? Downfalls? |
use virus with reduced pathogenicity to stimulate response
-nat. occuring -art. attentuated + induced long-lived, appropriate immunity - unstable:biochemically(virus) and genetically(reversion to virulence) not possible to produce in all case contamination can result in disease for immunodeficient, pregnany patients |
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Vaccine
Administration? Adjuvants? |
1. oral, subcutaneous/scarification, intramuscular
2.ENHANCE IMMUNE RESPONSE and are included in inactivated and subunit vaccines. Safe for human use. |
