What do the following have in common? Can you Identify the picture below? Characteristics of Life • • • • • • Made of Cells Reproduce Metabolize (energy) Grow Respiration Respond to environmental changes • What do we know about viruses? • Why are viruses not classified in any of the 6 kingdoms? VIRUSES Organic? BACTERIOPHAGE RABIES FLU EBOLA Virus Characteristics • • • • • Do not use energy Do not reproduce Do not grow Do not respond to environment Are not cellular • Obligate intracellular parasites • OLD ways of thinking – viruses Contain 2 of 4 organic compounds – Proteins and nucleic acids New: 4 of 4 organic compounds Virus Defined • Infectious pathogen that infects living cells, replicates inside cells making new viral particles causing disease • DNA encased in a protein/carbohydrate coat Types of Viruses Polyhedral helical enveloped Types of Viral Diseases • • • • • Rabies Ebola (hemorrhagic) Flu (influenza) HIV Hepatitis WE can only treat symptoms of viruses!!! We can not CURE!! • • • • • • • • • Chicken pox Measles Rubella Mumps Smallpox Polio Yellow fever Parvovirus (canine) Dengue fever (hemorrhagic) • Herpes http://www.youtube.com/watch?v=Rpj0emEGShQ Hh` 1 2 4 3 http://www.youtube.com/watch?v=wLoslN6 • Lysogenic Infection: • Similar to lytic infection however important differences exist • Instead of immediately replicating, viral DNA incorporates itself into the host cell's DNA. • Will remain dormant for significant amounts of time. • Give certain conditions (stress), the virus will enter it's lytic phase similar to a normal lytic infection Vaccinations • Stimulates Active immunity • Injection of portion of virus (virus particles) that stimulate an immune response….causes body to make antibodies against particular diseases Immune Responses • Passive – Formation of antibodies – To the fetus thru the placenta, thru breastmilk, thru administration of plasma (artificial) • Active – Formation of your own antibodies – Vaccinations – by contracting an infectious disease by exposure of an antigen What are they? • Proteinaceous infectious particles – Infect brain or other neural tissue – Untreatable and fatal – β sheets are thought to lead to amyloid aggregation. Bovine Spongiform Encephalopathy • Also known as "Mad Cow Disease" • Infected animals act strangely and can be aggressive • Spread rapidly through Britain by rendering infected animals into cattle feed Scrapie • Recognized in sheep and goats for more than 250 years • 1982 1st identified as a prion disease Kuru “laughing death” • • • • New Guinea Muscle weakness, loss of coordination, tremors, inappropriate episodes of laughter or crying Was the most common death of women Mortuary feasting – Forbidden by Australian government in 1950’s http://learn.genetics.utah.edu/content /begin/dna/prions/ Viroid • Single strand of RNA (THAT’S IT!!) • Infects plants • 1 viroid disease has killed over 10 million coconut palms in the Philippines