Viruses and Bacteria

1. Viruses and Bacteria

2. What do these diseases have in common? Mumps http://www.kcom.edu/faculty/chamberlain/Website/lectures/lecture/IMAGE/MUMPS.GIF Hepatitis B http://www.idph.state.il.us/images/hepatitisb.jpg Measles http://www.idph.state.il.us/images/measles.jpg Polio http://www.immune.org.nz/site_resources/Professionals/Diseases/Polio/Polio.jpg

3. It looks alive, acts alive… but its not! • Viruses are not living things. They differ from living things in several ways: • They need to be inside a living organism to reproduce themselves. • Outside the cell, they have no metabolism. • They do not have cell parts. (i.e. nucleus, mitochondria, etc) • They are composed of only a nucleic acid (DNA or RNA) inside a protein capsule.

4. Structure of a Virus Protein capsid DNA (or RNA) Tube http://mrsec.wisc.edu/Edetc/technologist/thumbnails/Matt/Virus_diagram.jpg Tail Fiber http://www.humanillnesses.com/images/hdc_0001_0001_0_img0008.jpg http://www.aidsactioncoalition.org/images/hiv_virus.gif

5. Viral Reproduction • In order to reproduce: • A virus attaches to a host cell. • The virus injects the cell with its DNA. • The viral DNA commands the cell to make more viral protein and DNA. • The cell then ruptures, releasing hundreds of new viruses. http://porpax.bio.miami.edu/~cmallery/150/gene/sf11x1virus.jpg

6. No, they aren’t from the 70’s. • Retroviruses • These are viruses that store their genetic information as RNA. • Example: HIV http://international.ucla.edu/cms/images/hiv_virus.jpg

7. HIV • Infects white blood cells • Newly made viruses are released into blood stream by exocytosis and infect other with blood cells • Self Check: What is exocytosis? • Since it is a provirus, cells still function normally. Therefore a person may appear healthy, but can still transmit the virus.

8. How it works…… • Uses RNA to create a copy of its DNA. • Inserts the DNA copy into the cell of the host. • Retroviruses can remain dormant for varying lengths of time before they become active. http://hiv.buffalo.edu/./images/hiv_virus_in_action.jpg

9. Viral Reproduction Cycles • Lytic Cycle: A virus enters a cell, makes copies of itself, and causes the cell to burst. • Lysogenic Cycle: A virus integrates its DNA into the DNA of the host cell, and the viral genetic information replicates along with the host cell’s DNA. Prophage: The viral DNA that is embedded in the host’s DNA. (Provirus)

10. Virus Overview • Defining Characteristics • Protein Coat • DNA or RNA Core • Must have a host to reproduce • Examples of diseases caused by viruses: Common Cold, Flu, AIDS, Smallpox, Polio, West Nile, Hepatitis, Chickenpox

11. Chicken pox • May remain in your body as a provirus and reoccur later in life as Shingles if they enter a lytic cycle

12. Other Common Viruses

13. The papilloma virus causes warts like those found commonly on hands and fingers.

14. Bacteria and Archaea • Bacteria are living, unicellularprokaryotes. • Divided into two kingdoms: Eubacteria and Archaebacteria • Heterotroph or autotroph (most use chemosynthesis). • Types of Bacteria are classified based on their shape, type of cell wall, and movement. http://fig.cox.miami.edu/~cmallery/150/proceuc/c27x3proc_shapes.jpg

15. Bacterial Shapes • Bacilli: rod shaped • Cocci: spherical • Spirilla: spiral, corkscrew

16. Binary Fission • When a bacteria grows so that it has doubled in size, it replicates its DNA and divides in half • Is this sexual or asexual? • Identical or different daughter cells?

17. Conjugation • Some bacteria are able to exchange genetic information • A hollow bridge forms between two bacteria and genes move from one cell to the other • Increases genetic diversity of a population

18. Spore Formation • Spores are formed when the bacteria produces a thick internal wall that encloses the DNA and part of the cytoplasm • Why do you think this would be beneficial for bacteria?

19. Spore Formation • Occurs when conditions are unfavorable for growth • Can remain dormant for years until conditions improve

20. We’re not all bad…. • Bacteria are most widely known for causing diseases such as strep throat, tetanus, meningitis, and tuberculosis. • However, most bacteria are very useful: • E. coli helps us digest our food. • Many are important decomposers in our ecosystem. • Rhizobiumprovides plants with nitrogen. • A few bacteria are used to clean up small oil spills in the ocean. http://www.youtube.com/watch?v=VXoz8xpwJbU

21. But some of us are… • Pathogens: disease causing agents. • Bacteria produce diseases in 2 ways: • Damage cells and tissues of infected organisms by breaking them down for food. • Release toxins (poisons) that travel throughout the body interfering with the normal activity of the host. • Examples of diseases caused by bacteria: • Lyme Disease, Tetanus, Diptheria, Bacterial meningitis, Strep throat, Tooth decay

22. Strep ThroatStrep throat is caused by Group A Streptococcus bacteria. It is the most common bacterial infection of the throat. • Symptoms may be mild or severe. • You usually start to feel sick about 2 to 5 days after you come in contact with the bacteria. • Symptoms usually begin suddenly, and can include: • Fever that begins suddenly and is often highest on the second day • Red throat, sometimes with white patches • Sore throat • Headache • Nausea • Chills • General ill feeling • Loss of appetite and abnormal taste • Swollen lymph nodes in the neck • Difficulty swallowing • Some strains of strep throat can lead to a scarlet fever-like rash. This rash is thought to be an allergic reaction to toxins made by the strep bacteria. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001663/

23. Pulmonary tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis (M. tuberculosis). You can get TB by breathing in air droplets from a cough or sneeze of an infected person. In the United States, most people will recover from primary TB infection without further evidence of the disease. The infection may stay asleep or inactive (dormant) for years. However, in some people it can reactivate. Symptoms The primary stage of TB usually doesn't cause symptoms. When symptoms of pulmonary TB occur, they may include: Cough (usually cough up mucus) Coughing up blood Excessive sweating, especially at night Fatigue Fever Unintentional weight loss Other symptoms that may occur with this disease: Breathing difficulty Chest pain Wheezing Tuberculosis http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001141/

24. Tetanus Clostridium tetaniproduces endospores which can enter deep cuts or wounds on the skin. Since these wounds can be hard to clean, the endospores can germinate and produce a toxin that the blood carries to the nerve cells in the spinal cord. Tetanus is the immunization used to treat this. Causes joint stiffening also known as “lock jaw”.

25. Lyme Disease Lyme disease is caused by bacteria called Borrelia burgdorferi (B. burgdorferi). Blacklegged ticks carry these bacteria. The ticks pick up the bacteria when they bite mice or deer that are infected with Lyme disease. You can get the disease if you are bitten by an infected tick. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002296/

26. http://www.webmd.com/oral-health/guide/dental-health-cavitieshttp://www.webmd.com/oral-health/guide/dental-health-cavities Cavities occur as a result of tooth decay. Tooth decay is the destruction of tooth structure. Tooth decay can affect both the enamel (the outer coating of the tooth) and the dentin (the inner layer of the tooth). Tooth decay occurs when foods containing carbohydrates (sugars and starches) such as breads, cereals, milk, soda, fruits, cakes, or candy are left on the teeth. Bacteria that live in the mouth digest these foods, turning them into acids. The bacteria, acid, food debris, and saliva combine to form plaque, which clings to the teeth. The acids in plaque dissolve the enamel surface of the teeth, creating holes in the teeth called cavities. Dental Cavities

27. Cholera • Cholera is caused by the bacterium Vibrio cholerae. The bacteria releases a toxin that causes increased release of water in the intestines, which produces severe diarrhea. • Cholera occurs in places with poor sanitation, crowding, war, and famine. Common locations for cholera include: • Africa • Asia • India • Mexico • South and Central America • People get the infection by eating or drinking contaminated food or water. • http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001348/

28. Botulism is a rare but serious illness caused by Clostridium botulinum bacteria. The bacteria may enter the body through wounds, or they may live in improperly canned or preserved food. • It produces spores that survive in improperly preserved or canned food, where they produce toxin. When eaten, even tiny amounts of this toxin can lead to severe poisoning. • The foods most commonly contaminated are home-canned vegetables, cured pork and ham, smoked or raw fish, and honey or corn syrup. • Botulism may also occur if the bacteria enter open wounds and produce toxins there. • About 110 cases of botulism occur in the U.S. per year. Most of the cases are in infants. • http://en.wikipedia.org/wiki/Botulism

29. Vaccinations • A weakened form of the pathogen (virus/bacteria) is used to stimulatethe production of antibodies. • However, bacteria and viruses have very high reproductive rates, which result in many mutations. • Thus, bacteria and viruses evolve quickly, often requiring a different vaccine every year. http://www.biojobblog.com/vaccination%5B1%5D.JPG http://www.biojobblog.com/vaccination(5).jpg

30. Antibiotics • Antibiotics block the growth and reproduction of bacteria • Used to treat bacterial infections