Module10a virology-120620071932-phpapp02
- 1. Choose me !!!!!! Virology Morphology & Background Common viruses Viral Diseases
- 2. Background Information:) s virus are parasites, s all cells can be not cells parasitized by s virus are packages virus, they only of genetic info - attack closely nucleic acids in related organisms protein coats s virus comes from a s virus only supplies latin word “poison” information, rest is or “slime” dependent on host
- 3. What are viruses? s virus = “poison” s with genetic material (DNA or RNA) and protein coat (capsid). s obligatory intracellular parasites. s infect the cells of a biological organisms. s they replicate by using the host cell’s metabolic“machinery”.
- 4. Definition of Terms: s Capsid- protein shell, or coat, that encloses the nucleic acid genome s Capsomere – Morphologic units of virus seen under the EM on the surface of icosahedral virus particles • Represents clusters of polypeptide s Defective virus – virus particle that is functionally deficient in some aspect of replication
- 5. More terms: s Envelope – lipid containing membrane that surrounds some virus particles • Acquired during viral maturation by a budding process thru a cellular membrane s Nucleocapsid – protein nucleic acid complex representing the packaged form of the viral genome s Subunit – single folded viral polypeptide chain
- 6. s Structural units – Basic protein building blocks of the coat. • Usually a collection of more than one nonidentical protein unit. • The structural unit is often referred to a protomer. s Virion – Complete virus particle. In some instances, the virion is identical to the nucleocapsid. In more complex virions, this includes the nucleocapsid plus a surrounding envelope.
- 7. Background Information: s Dmitri Iwanowski - s Are viruses alive?? 1892 first isolation they contain of TMV macromolecules s Martinus Beijerinck but does not - filterable viruses reproduce directly s Wendell Stanley - --- virions are intact, non- 1935 purified & replicating virus crystallized TMV particles ( no life)
- 8. Basis of classification s Virus morphology s Virus genome • Size properties • Shape • Nucleic Acid ( DNA • Type of symmetry or RNA ) • Presence & absence • Size of genomes in of peplomers kb (kilobase pairs ) • Presence & absence • Strandedness (single of membranes or double ) • Nucleotide sequence
- 9. Basis for Classification: s Host Range s Size • Plant virus • 25 nm to 300 nm • Animal Virus • 1/10 to 1/3 of • Bacteriophage bacteria • no cytoplasmic • Specificity cultivars structures ( plants), race or • can be 77 genes strains, receptors or 3 genes but (protein) still very lethal
- 10. SIZE s Most viruses with capsid = between 10-300 nm
- 11. Structure: s Nucleic Acid core surrounded by protein s Viral Envelope - naked or enveloped s Nucleic Acid - DNA or RNA
- 12. s Genome organization & replication s Antigenic properties • Gene order • Gene number s Biologic properties • Position of open including : reading frames • Natural host range • Patterns of • Mode of replication transmission • Cellular sites • Vector relationship • Pathogenecity • Tissue tropisms • Pathology
- 13. s Physiochemical s Virus protein Properties of the properties virion • Number • Molecular mass • Size • Buoyant density • Functional activities • pH stability • Amino acid • Thermal stability sequence • Susceptibility to agents • Modifications & – Ethers special functions – Detergents – Transcriptase – Reverse trans. – Neuramidase – fusion
- 14. Types of Structure s Four morphological types: • 1. Helical Viruses • 2. Icosahedral viruses • 3. Enveloped viruses • 4. Complex viruses
- 15. Helical virus -Resemble long rods, may be rigid or flexible -Viral nucleic acid found within a hollow cylindrical capsid. -with single type of protomers stacked around a central axis to form a tube; eg. Tobacco mosaic virus.
- 16. Icosahedral spherical appearance but capsomeres arranged in a geometrical pattern like a soccer ball; eg.hepatitis B
- 17. Enveloped with outer lipid layer = viral envelope
- 18. Complex -- with extra structure such as protein tails, complex outer walls; eg. Bacteriophages, Poxviruses.
- 19. Life Cycle: s outside the host there is no replication s Stages : • -->Adsorption • --> Penetration • --> Uncoating • --> Viral synthesis • --> Maturation • --> Release
- 20. Multiplication of Viruses s Lytic cycle – ends with the lysis and death of the host cell. s Lysogenic cycle- host cell remains alive
- 22. Taxonomy: s ICTV - International Committee on Taxonomy of Virus s Family Name -- Viridae -- Retroviridae s Genus -- Virus -- Lentivirus s Specie -- English -- HIV s Hepadnaviridae -- 7 DNA - Hepatitis
- 23. Misc. Information: s Replication applicable to all virus s Plaque count - PFU Plaque forming units s One Step Growth Phase -- Latent ---> Burst Period
- 24. Common viruses in animals: s Line 1 - Family s Line 2 - Classification based on N.A. s Line 3 - Properties s Line 4 - Virus (species or Genus) s Line 5 - Diseases *** Legend
- 25. s Herpesviridae s DNA virus s Enveloped dsDNA s Herpes simplex 1&2, Varicella zoster, EBV, cytomegalovirus CMV s cold sores, genital herpes, shingles, mononucleosis, birth defects
- 26. s Poxviridae s DNA virus s Enveloped dsDNA s Smallpox virus s Smallpox ( variola )
- 27. s Hepadnaviridae s DNA virus s Enveloped dsDNA s Hepatitis B virus s Hepatitis B
- 28. New Nomenclature for Hepatitis Virus s Hepatitis A • HAV virus • Etiologic agent of infectious Hepatitis • A picornavirus, the prototype of a new genus, Hepatovirus • Anti-HAV – antibody to HAV. Detectable at onset of symptoms; lifetime persistence • IgM antibody
- 29. Hepatitis B s Antibodies for Hep B s HBV- Hepatitis B • Anti-HBs virus • Anti-HBe s Etiologic agent of • Anti-HBc serum hepatitis s A hepadnavirus • IgM class Antibody s HBsAg, HBeAg, HBcAg
- 30. Hepatitis C s HCV – Hepatitis C Virus s A common etiologic agent of post transfusion hepatitis s A Flavivirus, genus Hepacivirus s Anti-HCV – antibody to HCV
- 31. Hepatitis D s Hepatitis D Virus s Etiologic agent of delta hepatitis s Causes infection only in presence of HBV s HDAg – Delta antigen, detectable only in early acute HDV infection s Anti-HDV - Antibody
- 32. Hepatitis E s HEV – Hepatitis E Virus s Enterically transmitted hepatitis virus s Causes large epidemics in Asia, North & West Africa and Mexico s Fecal-oral or waterborne infection s Unclassified
- 34. s Papoviridae s DNA virus s naked dsDNA s Human papillomaviruses s Warts
- 35. Polyomaviruses s Small (45nm ) naked, heat stable, ether resistant virus s Cubic symmetry with 72 capsomeres s Circular, double stranded DNA s JC virus, BK virus, SV40 virus s Formerly part of Papoviridae family
- 36. s Adenoviridae s DNA virus s Naked dsDNA s Human adenovirus s respiratory, enteric diseases, infectious pinkeye
- 37. Parvovirus s Naked Single stranded DNA virus s Cubic symmetry with 32 capsomeres s 5.6 kb in size s Requires the presence of adenovirus or herpesvirus as helper ( defective )
- 38. s Retroviridae s RNA virus s Enveloped + strand RNA s HIV-1 & 2, HTLV-1 &2 s AIDS , T cell leukemia
- 39. Life Cycle of HIV Virus
- 40. Astroviruses s 28-30 nm in diameter s Exhibit a distinctive star-like morphology under the EM s Ss + sense RNA, 6.4 – 7.4 kb in size s Causes diarrheal illnesses s Transmitted by fecal-oral route thru contaminated food or water
- 41. Arboviruses (arthropod borne) s Arenaviridae s Bunyaviridae s Flaviviridae s Filoviridae s Reoviridae s Togaviridae
- 42. Arenaviruses s Generally associated with rodent- transmitted disease in humans. s Each virus usually is associated with a particular rodent host species in which it is maintained s Divided into two groups: • the New World or Tacaribe complex • the Old World or LCM/Lassa complex.
- 43. Filoviruses
- 44. s Flaviviridae s RNA virus s enveloped + strand RNA s Yellow & Dengue fever , Hep C virus s Yellow & Dengue fever, Hepatitis C
- 46. Types of Dengue s Non-fatal dengue fever (DF) s Fatal Dengue Hemorrhagic fever (DHF) s Dengue Shock Syndrome ( DSS)
- 47. Serotypes of Dengue s 4 serotypes s DEN-1, DEN-2, DEN-3, DEN-4 s DEN-2 shows greatest antigenic and genotypic distance from the others s Protective immunity after infection is homotypic (Which means if your really unlucky u can have dengue __ times.)
- 48. More types of Flavivirus s Eastern & Western Encephalitis s St. Louis Encephalitis s West Nile Fever s Japanese B Encephalitis s Yellow Fever
- 49. s Reoviridae s RNA virus s naked dsRNA s Rotavirus s Infant diarrhea
- 50. s Bunyaviridae s RNA virus s Enveloped - strand RNA s Hantavirus s Respiratory distress syndrome
- 51. s Togaviridae s RNA virus s Enveloped + strand RNA s Alphavirus, Rubella virus s encephalitis, Rubella (German measles)
- 52. Picornaviruses s Enterovirus s Rhinovirus • Transient inhabitants • Isolated chiefly from of the human the throat and nose alimentary tract • More than 100 • Poliovirus species based on • Coxsackie virus receptors – ICAM -1 • Paraechovirus – LDLR – Echovirus 22 – Echovirus 23
- 53. s Picornaviridae s RNA virus s Naked + strand RNA s Enterovirus, Poliovirus, echovirus, Rhinovirus, hepatitis A virus s Polio, Myocarditis, pericarditis, colds, Hepatitis A
- 54. s Coronaviridae s RNA virus s Enveloped + strand RNA s Coronavirus s upper respiratory tract infections
- 55. s Calciviridae s RNA virus s naked + strand RNA s Norwalk Agents s Gastroenteritis
- 56. s Orthomyxoviridae s RNA virus s Enveloped - strand RNA s Influenza virus s Influenza
- 57. s Rhabdoviridae s RNA virus s enveloped - strand RNA s Rabies virus s Rabies
- 58. s Paramyxoviridae s RNA virus s enveloped - strand RNA s Mumps, measles virus, Parainfluenza virus, Respiratory syncitial vir. s mumps, rubeola, Croup, Bronchiolitis
- 59. Recent Viral Diseases s SARS- severe acute respiratory syndrome
- 60. Avian Flu- spread of H5N1 strain
- 61. Influenza Pandemic (1918-1919) – TEM of Spanish Influenza Virus (negatively-stained); subtype H1N1; H2N2; H3N2 25 million deaths in 25 weeks 20% of world population affected. 1957-1958 1968-1969 Next pandemic ????
- 62. Virus entry into an animal cell
- 63. What other roles could be attributed to viruses other than being pathogens? s Basic research, molecular biology and biotechnology s Horticulture s Cross- protection s Gene therapy s Phage therapy s Viro-therapy
- 64. Continuation…….. s Material Science and Nanotechnology- In April 2006, MIT scientists created nanoscale metallic wires using a genetically-modified virus. The MIT team was able to use the virus to create a working battery with an energy density up to three times more than current materials. The potential exists for this technology to be used in liquid crystals, solar cells, fuel cells, and other electronics in the future. s Biological warfare- synthesis/recreation of viruses in laboratory (eg. 1918 flu virus, smallpox virus- Variola major)