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(Tayo)semina presentation

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Assay of viral particles.

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(Tayo)semina presentation

  1. 1. ASSAY OF VIRAL PARTICLES. PRESENTED BY IDOWU TEMITAYO .O. MATRIC NUMBER: 0903010024 DEPARTMENT OF BIOLOGICAL SCIENCES, COLLEGE OF NATURAL SCIENCES,JOSEPH AYO BABALOLA UNIVERSITY, IKEJI-ARAKEJI, OSUN STATE.
  2. 2. OUTLINEDEFINITION OF TERM.VIRAL GROWTH RECOGNITION.COMMONLY USED LABORATORY METHODS FOR THE DETECTION OF VIRUSES.QUANTIFICATION OF VIRUSES.TRADITIONAL METHODS.MODERN METHODS.CONCLUSION.
  3. 3. DEFINITION OF TERMSWHAT ARE VIRUSES?“A PIECE OF BAD NEWS WRAPPED UP IN A PROTEIN”WHAT IS AN ASSAY?ASSAY IS AN INVESTIGATIVE (ANALYTIC) PROCEDURE IN LABORATORY MEDICINE, MICROBIOLOGY, ENVIRONMENTAL BIOLOGY, AND MOLECULAR BIOLOGY FOR QUANTITATIVE ASSESSING OR QUALITATIVELY MEASURING THE PRESENCE OR AMOUNT OR THE FUNCTIONAL ACTIVITY OF A TARGET ENTITY (Mckean et al., 2005).
  4. 4. VIRAL GROWTH RECOGNITION.Recognition of a diseased stateSystemic infection.The production of a local lesion such as plaque.In tissue culture the culture will undergochange with the production of cytopathiceffect (CPE), namely the destruction of thecell, syncytia formation, or cellulartransformation.
  5. 5. Plate 1: CYTOPATHIC EFFECT (CPE)Source: Wikipedia
  6. 6. COMMONLY USED LABORATORY METHODS FOR THE DETECTION OF VIRUSES.Measure of virus infectivity.Examination of viral serology (that is, host antibody responses to the virus).Molecular methods.
  7. 7. QUANTIFICATION OF VIRUSES• TRADITIONAL METHOD-: These are industry standard methods that have been used for decades but are generally slow and labour intensive.• MODERN METHOD-: These are relatively new commercially available product and kits that greatly reduce quantification time.
  8. 8. TRADITIONAL METHOD
  9. 9. PLAQUE ASSAY Plate 2: Viral Plaques of Herpes Simplex Virus. Source: Wikipedia
  10. 10. FLUORESCENT FOCUS ASSAY (FFA): Plate 3: Fluorescent Focus Assay Source: C.D.C
  11. 11. 50% TISSUE CULTURE INFECTIVE DOSE (TCID50)This endpoint dilution assay quantifies the amount of virus required to kill 50% of infected hosts or to produce a cytopathic effect in 50% of inoculated tissue culture cells.
  12. 12. PROTEIN ASSAY:There are several variations of protein- based virus quantification assays.In general, these methods quantify either the amount of all protein or the amount of a specific virus protein in the sample rather than the number of infected cells or virus particles.
  13. 13. HEMAGGLUTINATION ASSAY:The hemagglutination assay (HA) is a common non-fluorescence protein quantification assay specific for influenza. SINGLE RADIAL IMMUNODIFFUSION ASSAY:Single Radial Immunodiffusion Assay, also known as the Mancini method, is a protein assay that detects the amount of specific viral antigen by immunodiffusion in a semi-solid medium (e.g. agar).
  14. 14. MODERN METHODS
  15. 15. Flow cytometry: MODERN METHODS: A virus counter quantifies the number of intact virus particles in a sample using fluorescence to detect proteins and nucleic acids.Quantitative Polymerase Chain Reaction (qPCR):Quantitative PCR utilizes polymerase chain reaction chemistry to amplify viral DNA or RNA to produce high enough concentrations for detection and quantification by fluorescence.
  16. 16. Enzyme-Linked Immunosorbent Assay (ELISA): ELISA is a more modern variation of a protein assay that utilizes a specific antibody linked to an enzyme to detect the presence of an unknown amount of antigen (i.e. virus) in a sample.
  17. 17. CONCLUSIONA basic principal of science ismeasurement or quantitation,therefore being able to accuratelyquantify virus numbers became anecessity.

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