Test 3

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Test 3
2011-04-04 13:46:21

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  1. Components of Viruses of Bacteria
    • Nucleic Acids- DNA or RNA
    • Capsid
    • Nucleocapsid
    • Attachment proteins or spikes
    • Naked or enveloped
  2. Capsid
    Protein coat
  3. Nucleocapsid
    Nucleic acid + capsid
  4. Enveloped
    Extra layer, lipid, or protein
  5. Isometric
    • Adenovirus
    • A sphere made of triangles
    • No envelope
  6. Helical
    • Tobacco mosaic virus
    • Rod shaped
    • No envelope
  7. Complex
    • T4 bacteriophage
    • Has a tail and collar
    • No envelope
  8. Productive Phage/Host Infection
    • Lytic phage replication
    • Continuous production
  9. Latent State of Phage/Host Interaction
    • Virus DNA integrates
    • Host modified
  10. Attachment of Lytic Phase Multiplication
    • Phage binds receptor on host cell
    • Major basis for host specificity
  11. Penetration of Lytic Phase Multiplication
    • Nucleic acid enters host cell
    • Intracellular state begins
    • Vulnerable to restriction endonucleases
  12. Transcription and Translation of Lytic Phase Multiplication
    • Copy and express phage genes by host machinery
    • Early proteins- nuclease, phage DNA synthesis
    • Late proteins- assembly and lysis of host
  13. Assembly of Lytic Phase Multiplication
    Assembly into intact virions
  14. Release of Lytic Phase Multiplication
    • Lysozyme
    • For T4, burst size of 200, total time 30 min
  15. Steps of Lytic Phase Multiplication
    • Attachment
    • Penetration
    • Transcription and translation
    • Replication of DNA and synthesis of proteins
    • Assembly
    • Release
  16. Filament Phage
    • M13 and fd
    • Adsorb on the tip of F+ pilus
    • Assembles as they exit
    • Bacterial host multiplies slowly
    • -Carrier cells
  17. Cholera
    • Severe watery diarrhea, vomiting
    • Ingestion of bacteria by drinking fecally contaminated water or foods
    • Bacteria produces toxin
  18. Toxin of Cholera
    • Causes intestinal cells to continuously secrete chloride ions into lumen
    • Other electrolytes follow resulting in large volume of fluid released
  19. Replication Pathway of Latent Phage Replication
    • Lytic
    • Quickly takes over host; ultimately kills
  20. Integration Pathway of Latent Phage Replication
    • Lysogenic
    • Phage genome integrates into host DNA – prophage
    • -Done by site specific recombination
    • Will remain in cell and passed onto daughter cells
  21. Site Specific Recombination of Integration of Phage DNA
    • Specific phage genomes will synapse and insert at the same point in bacterial chromosome
    • Between the galgene and biogene
    • Phage is specific to certain receptors
  22. Lysogenic Cells
    • No other phage can infect
    • Lambda phage and E. coli protect the phage from others
    • Conversion
    • -Confer new properties to lysogen
    • -Toxins of
    • •Clostridium botulinum
    • •Corynebacterium diphtheriae
    • •Vibrio cholerae
  23. Lysogenic to Lytic
    • During lysogenic state
    • A repressor controls genes for excision (removal) of phage DNA
    • Upon damage of cell, repressor removed and excisase made
    • Phage induction ensues
    • Excision of phage genome
    • Productive infection begins with creation of new phage and eventual lysis of host
  24. Specialized Transduction
    • Performed only by temperate phages
    • Removes part of chromosome during excision
    • Phage becomes defective
  25. Generalized Transducion
    • T4 Bacteriophage
    • Occurs during assembly
    • Only 1 transduces
    • Bacterial DNA and randomized pieces are transduced
  26. Specialized Transduction
    • Lambda
    • Occurs during excision
    • All transduce
    • Specific (gal/bio) is transduced
  27. Animal Virus
    • DNA/RNA; ss or ds; segmented or single
    • Isometric, helical, pleomorphic
    • Presence (or absence) of envelope
    • Matrix protein inside envelope
    • Attachment spikes/proteins
  28. Types of Animal Viruses
    • Enteric Viruses
    • Respiratory Viruses
    • Zoonotic Viruses
    • Sexually Transmitted Viruses
  29. Enteric Viruses
    • Gastroenteritis by rotavirus
    • Ingest these
  30. Respiratory Viruses
    Influenza by influenza virus
  31. Zoonotic Viruses
    • Rabies by rabies virus
    • Transmitted from animal to human
    • Bats, inhaling feces
  32. Sexually Transmitted Viruses
    Genital warts by papillomaviruses
  33. Acute Infections
    • Short duration
    • Productive infection
  34. Persistant Infections
    • Latent infection
    • Chronic infection
    • Slow infection
  35. Acute Infection Reproduction
    • Attachment
    • Entry
    • Uncoating
    • Transcription and replication
    • Maturation
    • Release
  36. Attachment of Acute Infection Reproduction
    • Several attachment proteins required- usually glycoprotein receptors
    • May bind to more than one kind of receptor
    • Usually species specific, unless mutated
    • Use our receptors as the viruses inceptor
  37. Entry of Acute Infection Reproduction
    Envelope fusion or endocytosis
  38. Envelope Fusion
    Viral envelope fuses with host membrane
  39. Endocytosis
    • Host membrane surrounds virus
    • Can be done with naked or enveloped virus
  40. The whole variant enters with animal
    Can enter the host by endocytosis or by envelope fusing
    What are two ways animal viruses differ from phage in entry of their host cell?
  41. Uncoating of Acute Infection Reproduction
    Nucleic acid separates from protein coat
  42. Transcription and Replication of Acute Infection Reproduction
    • Based on RNA or DNA; ds or ss
    • Virus may bring own enzymes for replication
    • -RNA dependent RNA polymerase
    • -Enzyme does not exist in host
    • Otherwise, all enzymes/proteins are encoded on viral genome or used from host
  43. Needs to become double stranded
    •Could wait for another DNA polymerase to become dsDNA or brings his own
    Transcription from dsDNA to mRNA
    Translation of virus proteins
    •Could make more nucleocapsids
    Has a DNA strand that only synthesizes single strands of DNA
    You have to come or bring something as a dsDNA virus
    If a virus entered a host cell as a single stranded DNA genome what would it require to begin synthesis of viral proteins as well as genome replication?
  44. Maturation of Acute Infection Reproduction
    • Assembly of nucleic acid with capsid protein
    • Usually takes place in an organelle
  45. Release of Acute Infection Reproduction
    Lysis or budding
  46. Lysis
    Host cell dies due to lack of metabolic functions
  47. Budding
    • Often associated with persistent infections
    • Picks up envelope from host
  48. Genetic Reassortment
    • Infection of one cell by two different segmented viruses
    • Usually causes zoonoses
    • -West Nile virus
    • -Avian influenza
    • -Swine influenza
    • -Can cause pandemics – worldwide epidemics
    • Influenza strains for infecting different species of animals and birds
    • •Can be coinfected by 2 different strains of flu
  49. Influenza Genome
    • Eight segments of RNA
    • •Hemagglutinin encoded for attachment to host
    • A human can have antibodies that recognize human influenza hemagglutinin
  50. Coinfection of Genetic Alterations
    Avian influenza and human influenza can infect the same host cell of a pig or duck
  51. Antigenic Shift
    • Human influenza with avian segment encoding hemagglutinin
    • Human antibodies do not recognize the avian hemagglutinin
  52. Spanish flu
    Asian flu
    Hong Kong flu
    Russian flu
    4 Influenza Pandemics
  53. DNA polymerase from host
    As a dsDNA virus, what enzyme would you use to make more genome?
  54. Latent Infections
    • Infection to symptomless to reactivation
    • -Herpesvirus: HSV-1, genital herpes HSV-2
    • -Varicella-zoster virus causing chicken pox then shingles upon reactivation
  55. Chronic Infections
    • Infectious virus is detected at all times
    • Continues to produce more virus
    • Hepatitis B and C
  56. Hepatitis B and C
    • Infects the liver and causes inflammation and scarring
    • Can be acute, but generally turns chronic
  57. Slow Infections
    • Infectious agent gradually increases
    • HIV
    • Prions (made of protein not a virus)
  58. Prions
    • Exclusively protein
    • Transmissible spongiform encephalopathies (mad cow, Creutzfeldt-Jakob)
    • Infects brain
    • -Brain material degrades, holes of no brain matter
    • Interacts with normal proteins and causes change in
    • quaternary structure
    • Miss folded proteins
  59. Viroids
    • Circular RNA
    • Infects only plants
  60. Stanley Pursiner
    Identified prions
  61. Creutzfeldt and Jakob
    Discover similar disease found in sheep in a man
  62. Gajdusek
    • Studies kuru spread by cannibalistic rituals in new Guinea
    • Won Nobel Prize in 1976
  63. Innate Defense
    • Proactive in keeping out microbes
    • Limited in identifying “foreigners”
    • •Pattern recognition
    • •Limited capability of identifying outside bacterias
  64. Adaptive Defense
    • Specialized
    • Must learn foreigner first then will “memorize"
  65. Types of Innate Defenses
    • First-line defenses
    • Cell communication
    • Phagocytes
    • Complement system
    • Inflammation
    • Fever
  66. First Line Defense
    • Physical barriers
    • Antimicrobials
    • Normal flora
  67. Physical Barriers
    • Skin – epithelial cells
    • -Carotene level constantly flaking off any skin that has microbes
    • Mucous membranes (surfaces inside the body)
    • Cilia
    • Mucus- traps mucus
    • Peristalsis; mucociliary escalator- moves mucus up to throat to be swallowed into stomach
    • Urine- washes the urethra, cleanses the surface
  68. Antimicrobial Substances
    • Sweat- high salt
    • Lysozome
    • Peroxidase enzymes
    • Lactoferrin
    • Defensins
  69. Lysozome
    • Targets peptidoglycan
    • Tears, saliva, mucus
    • Antimicrobial substance
  70. Peroxidase Enzymes
    • Produces oxidizing compounds
    • Toxic to bacteria
    • Saliva, milk, phagocytes
    • Antimicrobial substance
  71. Lactoferrin
    • Iron-binding
    • Bacteria need iron to grow, but body uses all of it
    • Saliva, mucus, mother’s milk
    • Antimicrobial substance
  72. Defensins
    • Disrupt bacterial membranes
    • Causes holes to form in cell walls
    • Antimicrobial substance
  73. Normal Flora
    • The mixture of microorganisms regularly found on body surface: bacteria (majority), fungus, protozoa
    • Provide competition- good bacteria uses nutrients so pathogens must fight for the nutrients to affect body
    • Can produce toxic substances to other bacteria
    • Termed opportunistic only when introduced to a new area and cause disease
  74. Probiotics
    • Oral administration of specific bacterial cultures
    • Found in yogurt products
    • -Lactobacillus bulgaricus, L. casei, S. thermophilus
    • Used to combat infectious diarrhea
    • Prevention of postoperative infections
    • Enhancement of immune functions
    • Give the intestinal tract an extra layer of protection
  75. Young child suffering from Cholera
    • Which of the following individuals would most
    • benefit the MOST from probiotics?
  76. Cells of Innate Immune System
    Leukocytes (white blood cells)
  77. Leukocytes
    • Immune defense cells
    • Granulocytes
    • Mononuclear phagocytes
    • Dendritic cells
  78. Granulocytes
    • Neutrophils: rapid response phagocytes; found in blood
    • Ready to respond to inflammatory signals
  79. Mononuclear Phagocytes
    Macrophages: engulfment and destruction; found in tissue
  80. Dendritic Cells
    Brings info to adaptive immunity
  81. Formation and Development of Blood Cells
    • Hematopoiesis
    • Originate from bone marrow’s hematopoietic stem cells
    • Develop from stem cells into special cells via signals called colony stimulating factors
  82. Cell Communication
    • Done by surface receptors and protein signals
    • Cytokines are specific signals
  83. Types of Cytokines
    • Chemokines
    • Colony-stimulating factors
    • Interleukins
    • Interferons
    • Tumor necrosis factors
  84. Chemokines
    • Cell chemotaxis
    • Cell movement
  85. Colony-Stimulating Factors
    • Multiplication and differentiation
    • Proteins that attach to surface receptors
    • Help differentiate between cells
  86. Interleukins
    • Diverse function usually stimulates cell, ex. inflammatory response
    • Play part in viruses, start to metabolize to respond to what’s going on in the body
  87. Interferons
    Cell responds to viral infections
  88. Tumor Necrosis Factors
    Inflammatory response, cell death
  89. Surface Receptor
    • On cell membrane
    • Receives signals and relays the signal to the interior of the cell
    • Signals are molecules that bind to the receptors
    • -ligands
  90. Sensor Systems of Cells
    • Toll-like receptors
    • NOD proteins
  91. Toll-Like Receptors
    • Found on cell surfaces
    • Identifies bacterial compound
    • Signals to cell nucleus
  92. NOD Proteins
    • Receptors in cell cytoplasm
    • Identifies bacterial compounds
  93. Complement System
    • System of inactive proteins circulating in blood and body
    • Proteins bind to “foreign” cells and immune system responds with other complement proteins to destroy invader
    • Find invader and take care of it
    • 3 ways to activate: classical, lectin, or alternative pathway
  94. Classical Pathway
    • Antibody recognizes foreign invader’s surface
    • Can attach to DNA or RNA
  95. Lectin Pathway
    • Mannose binding lectins (proteins) (MBL) recognizes mannose on bacterial surfaces
    • Combines to mannose
  96. Alternative Pathway
    • C3b binds to all surfaces; foreign surfaces allow C3b to remain
    • Body removes C3b cells
    • Bacteria and viruses don’t
  97. Classical, Lectin, and Alternative
    If a virus, then only classical and alternative would bind
    A bacterial cell enters through a cut. Which of the three complement proteins could bind?
  98. Activities of Complement
    • Inflammation
    • Bacterial cell lysis via membrane attack complex (MAC)
    • Opsonization
  99. Inflammation
    • Recruitment of phagocytes
    • C3b binding to cell
    • Dilation of blood vessels
    • Leakage of fluid from vessels
    • Migration of leukocytes to infected tissue
    • Signs include: redness, warmth, pain, swelling, altered function
  100. To recruit phagocytes to area of infection
    What is the main purpose of inflammation?
  101. Foreign Cell Lysis
    Assembly of complement proteins into a membrane attack complex to form pores in bacterial membrane
  102. Phagocytosis
    • 1.Chemotaxis
    • 2.Recognition/attachment
    • 3.Engulfment
    • 4.Fusion with lysosome
    • 5.Destruction
    • 6.Exocytosis
  103. Phagocytosis and Opsonization
    • C3b (opsonin) binds to cell surface – causes enhanced phagocytosis
    • Easily identified by phagocyte
  104. Fever
    • Triggered by macrophages emitting cytokines during inflammation
    • •Pyrogens
    • Reduces microbial growth
    • Activates and speeds up body defenses
    • Increases enzymatic rates
  105. Immunity
    • Acquiring an antibody response that protects against future infection of the same agent
    • Passive
    • Active
  106. Passive Immunity
    • Ig’s are given to body
    • Natural vs. artificial
  107. Active Immunity
    • Ig’s are generated by body
    • Natural vs. artificial
  108. Natural Passive Immunity
    Mother's milk
  109. Artificial Passive Immunity
    • Serum given
    • Immune serum globulin
    • Hyperimmune serum globulin
  110. Natural Active Immunity
    Natural exposure
  111. Artificial Active Immunity
    • Given infection on purpose
    • Vaccine
  112. Immune Serum
    • Pooled IgG by donor plasma
    • Several types of IgG offers some protection
  113. Hyperimmune Serum
    • Selected pooled Ig’s in high amount for a
    • specific disease
    • To treat or prevent disease
    • Examples; Hep A and B, tetanus, rabies
  114. Why Vaccines Work
    • Body is exposed to new antigen via vaccine imposing a primary immune response from the innate and adaptive
    • Memory is generated by the adaptive response
    • When exposure to antigen is experienced again, secondary immune response jumps in
  115. Clonol selection and expansion
    Which of the following terms best describes what occurs during an initial infection that eventually generates memory T and B cells specific for that particular infection?
  116. Vaccine
    • A pathogen or its products
    • Benefit of widespread vaccinations
    • -Herd immunity
    • Attenuated
    • Inactivated
    • –Whole agent vaccines
    • –Subunit vaccines
  117. Herd Immunity
    Although one person may not be immunized, if the people surrounding him are immunized, then they are protected
  118. Attenuated Vaccines
    • Living virus or bacterial cell
    • Can infect and replicate but does not cause symptoms or only mild symptoms
    • Different growth conditions or animal host; genetic engineering
    • Advantages- long lasting immunity- more antigens to react against (whole virus cell) and longer period of time the antigen will be in the body; exposure to non-immunized individuals
    • Disadvantages- exposure to non-immunize individuals; require refrigeration; not applicable to pregnant women; could mutate
    • Babies can’t handle flu mist because of low immune systems
    • Examples; yellow fever, rubella, typhoid fever
  119. Inactivated Vaccines
    • Microorganisms that cannot replicate
    • -Whole agents (whole cell or virus) and toxoids killed virus or bacteria by chemical
    • -Subunit agents: protein subunit: key
    • protein of surface, recombinant and polysaccharide: T independent B cell activation
    • Conjugate: polysacchaide linked to protein – initiate T dependent and T independent
    • Advantages- self contained; cannot mutate; subunit causes less side effects
    • Disadvantages-only one or a few antigens recognized; requires boosters due to low exposure time
    • Hepatitis A- inactivated virus
    • Hepatitis B- subunit agent
  120. Poliomyelitis Vaccine
    • Salk vaccine- inactivated
    • Sabin vaccine- attenuated
    • 1980 US is polio free; goal of eradication by 2000
    • -Money and culture
    • -Don’t want any part of western medicine
  121. Primary Response in Antibodies
    • Creates memory
    • New antigen
    • Slow – 10 days to 2 weeks
    • Clonal selection occurs
    • Low affinity
    • Memory cells formed
  122. Secondary Response in Antibodies
    • Anamnestic
    • Enhanced response to same agent
    • Stronger
    • Higher affinity
    • Faster
    • Longer lasting
  123. Specific Immunity Components
    • Humoral immunity (B cell and antibodies)
    • Cellular immunity (T cells)
  124. Humoral Immunity
    Eliminates pathogens and agents that don’t appear to be “self”
  125. Cellular Immunity
    Targets infected human cells
  126. Adaptive Immunity
    • B cells activated by antigens and T cells to make antibodies
    • T cells activated by dendritic and other T cells to identify cells in trouble
  127. Lymphoid System
    • Central area for B and T cells to come in contact with antigens
    • Lymph enters lymphatic vessel from tissue
    • Empties into vein
  128. Primary Lymphoid Organs
    • Bone Marrow
    • Thymus
  129. Secondary Lymphoid Organs
    • Lymph nodes
    • Spleen
    • Tonsils
    • MALT
    • SALT
  130. Antigens
    • Interacts with cells of immune system
    • Antibody
    • Lymphocyte
    • Can be proteins, nucleic acids, polysaccharides or glycolipids
    • Consist of antigenic determinants or epitopes
  131. Epitopes
    Specific regions on antigen that are recognized
  132. Antibodies
    • Immunoglobulins (Ig)
    • Glycoprotein
    • Structure- Arms of Ig are termed Fab region, stem is termed the Fc region
    • Function: bind to antigens
    • Produced by B cells
    • Five classes: IgM, IgG, IgA, IgD, IgE
  133. Variable Region of Antibody Structure-Function
    • Functions in binding to antigen
    • Accounts for specificity of antibody
  134. Constant Region of Antibody Structure-Function
    Heavy chain constant region determines antibody class
  135. IgG
    • Major Ig in serum – 80%
    • Opsonizes pathogens
    • Neutralizes toxins
    • Activates classical pathway
    • Crosses placenta
    • Produced in colostrum
  136. IgM
    • First Ig made
    • Cannot cross the placenta
  137. Secretory IgA
    • Produced at mucosal surfaces
    • Synthesized by B cells in MALT (Mucosa associated lymphoid tissue)
    • Abundant in breastmilk
  138. Dendritic Cells
    • Found under skin and mucosal linings
    • Samples all material for “foreign” proteins
    • Displays information on MHC
  139. Major Histocompatibility Complex (MHC)
    • On human cells present antigen fragments (protein, etc.) from inside cell
    • Two Classes: I and II
  140. MHC I
    All human cells present endogenous (self) proteins
  141. MHC II
    Macrophages, dendritic cells, B cells present exogenous (other than self) proteins
  142. T Cells
    • Have receptors on surface
    • Before activation T cytotoxic or T helper cells are termed naive
  143. Activated cytotoxic T cells (Tc)
    • Attack virus–infected cells
    • Have CD8 protein associated with T-cell receptor
    • Binds MHC I on other cells
    • Triggers apoptosis or cytolysis by release of perforin
  144. Activated helper T cells (Th)
    • Binds MHC II on other cells
    • Have CD4 protein on surface associated with T-cell receptor
    • Th1: macrophage activation; stimulate T cells
    • Th2: B-cell antibody response
  145. T Cell Activation
    • Dendritic cells pick up foreign antigens from periphery
    • Present antigen to T cells along with co-stimulatory molecule
    • T cell matures to produce surface receptors and release cytokines
  146. Tc Cell Activation
    • Binds to MHC I on human cell surface
    • If recognition occurs, cytotoxins are released
    • Cytokines released to “alert” neighbor cells
  147. Th1 Cell Activation
    • Recognizes antigens on MHC II by macrophage
    • Stimulates more active killing in macrophage
  148. B Cell Activation-T Dependent Antigen (Th2)
    • Antigen bound by B cell and internalized
    • Presented at B cell surface by MHC class II
    • Recognized by Th2 cell
    • B cell stimulated by T cell to proliferate into plasma cells and memory cells
    • Plasma cells make antibodies
  149. B Cell Activation-T Independent Antigens
    • No need for T-helper cell
    • B cell proliferation stimulated by polysaccharides or lipopolysaccharides on a bacterial surface
  150. Clonal Selection Theory
    • Ability of lymphocytes to recognize a specific antigen
    • For example: ability to respond to 100 million different epitopes due to production of almost 1 billion B cells
  151. Clonal Selection
    • Proliferation & differentiation of only subset of T or B cells stimulated by antigen and secondary signal
    • Yields active cells and memory cells