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Chapter 17

Chapter 17. Viruses & Prokaryotes. Information & Picture Sources: Botany by Nabors Holt Biology Textbook http://answers.yahoo.com/question/index?qid=20071210151745AAodh3J http://www.ucmp.berkeley.edu/archaea/archaea.html

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Chapter 17

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  1. Chapter 17 Viruses & Prokaryotes Information & Picture Sources: Botany by Nabors Holt Biology Textbook http://answers.yahoo.com/question/index?qid=20071210151745AAodh3J http://www.ucmp.berkeley.edu/archaea/archaea.html Major Groups of Prokaryotes Site by Kenneth Todar University of Wisconsin-Madison Department of Bacteriology Pink Monkey

  2. Part II: Bacteria

  3. The first thing you may think when someone says bacteria is “ germs” or disease However: Only about 1% of bacteria are disease causing.

  4. Bacterial soft rot of a bell pepper- with bacterium Erwinia carotovora http://www.sanger.ac.uk/Info/News-releases/gfx/040720-erwinia-300.jpg

  5. A potato rotted with Erwinia carotovora http://w3.rennes.inra.fr/umrbio3pE/equipes/resistance/images/obj-3-200.jpg

  6. Human arm infected with Methicillin-Resistant Staphylococcus Aureus - "MRSA"/"Staph" http://www.equipoc.net/main/process4.jpg

  7. Human throat infection with “strep” http://www1.indstate.edu/thcme/micro/strep/Slide9.JPG

  8. BUT: Many bacteria are helpful organisms! • Certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin • others live symbiotically in the guts of animals (including humans) or elsewhere in their bodies, • roots of some plants, convert nitrogen to usable form. • Bacteria make yogurt and put the sour in sourdough bread • help to break down dead organic matter • & make up the base of the food web in many environments.

  9. Helpful bacteria create all these foods Zesty Microbes Enliven the Palate, Provide Better Blueprint for Biofuels & Specialty Chemical Production -www.jgi.doe.gov

  10. Symbiotic bacteria in the human gut • Body fluid samples have yielded new information about the diversity of human metabolism across the globe — • about who eats what, and how their unique internal microorganisms handle the input. www.discover8.com

  11. Characteristics of Bacteria 1. Prokaryotes, - they lack a true membrane bound Nucleusor membrane bound organelles. 2.  Bacteria are the MOST NUMEROUSorganisms on Earth. 3. Almost all prokaryotes are smaller than the smallest Eukaryotes 4. They are unicellular(single-celled) organisms. 

  12. Things to know about bacteria: • Bacteria are among the earliest forms of life that appeared on Earth billions of years ago. • Fossils of bacteria have been found that are 2.5 BILLION years old. • Scientists think cyanobacteria created atmospheric oxygen as a waste product of photosynthesis. • They "eat" everything from sugar and starch to sunlight, sulfur and iron.

  13. There are 2 kinds of bacteria: - very different chemically & metabolically; that is why they are in 2 different kingdoms 1. Archaebacteria have been found in temperatures above the boiling point and in cold that would freeze your blood. 2. Eubacteria are the “regular” bacteria.

  14. 1. KINGDOM ARCHAE . • Scientists were shocked in the late 1970s by the discovery of an entirely new group of organisms -- the Archaea. • Most archaeans don't look that different from bacteria under the microscope, but they are difficult to culture, so their unique place among living organisms long went unrecognized. • However, biochemically and genetically they are as different from bacteria as you are.

  15. Archaea • Many books and articles still refer to them as "Archaebacteria", but that term has been abandoned because they aren't bacteria -- they're Archaea. • Live in unusually HARSH ENVIRONMENTS,where no other organism can survive, such as acidic hot springs, undersea volcanic vents, & highly salty water. • They are divided intoTHREE Groups, based on the Environment where they live: • Methanogens • Themoacidophiles • Extreme Halophiles

  16. A.METHANOGENS • Live in oxygen-free environments (anaerobic) • Oxygen is a Poisonto them, - can live only in ANAEROBICConditions, such as the Bottom of Swamps and in Sewage and the digestive track of animals.  • produceMethane Gas. • Swamp gas is methane produced by methanogens living in the waters of swamps, sewage or marshes. • Methane produced in the DIGESTIVE TRACTS of many animals & humans is called INTESTINAL GAS. • In the digestive track of cows they break down CELLULOSE, enabling cows to eat grass & plants.  • They are used inINDUSTRY to treat SEWAGE and to help PURIFY WATER.

  17. B.  THERMOACIDOPHILES • Can live in Water that is Extremely HOT(230 degrees F.) and ACIDIC (pH less than 2), two conditions that would kill other organisms.  • Can be found around HOT SPRINGS like those at Yellowstone National Park, No other organism can live in these waters!  Thermoacidophiles live near volcanic vents on land or near hydrothermal vents, cracks in the ocean floor miles below the surface that leak scalding acidic water.

  18. Sulfur, heat in volcanic vents with thermoacidophiles living there:

  19. C.  EXTREME HALOPHILES • Live in Extremely SALTYConditions.  • Found in the Great Salt Lake in Utah and the Dead Sea.  • Grow in water ten times saltier than seawater. • High salt concentrations would kill most bacteria, but this high concentration is beneficial to the growth of Extreme Halophiles, and these organisms use Salt to Generate ATP. • “HALITE” is the scientific term for the mineral- NaCl- salt

  20. EXTREME HALOPHILES

  21. Archaeans • Live in environments that are hostile to all other life forms. • But are not restricted to extreme environments; new research is showing that archaeans are also quite abundant in the planktonof the open sea. • Much is still to be learned about these microbes & these may be the kinds of life that scientists should look for on other planets & moons.

  22. 2. KINGDOMEUBACTERIA • The “true” bacteria, are all the organisms traditionally known as BACTERIA • -or- AS MOM WOULD SAY: "GERMS". • "EU" means TRUE.

  23. A. SHAPE: • Bacteria can be one of THREE Different Shapes:(BACTERIA USUALLY GAIN PART OF THEIR NAME FROM THEIR SHAPE.) 1.BACILLI are rod shaped bacteria. 2. COCCI -Sphere or ball shaped bacteria. - STREPTOCOCCIarechains of spheres - STAPHYLOCOCCIare clusters of spheres 3.SPIRILLAare Spiral shaped.

  24. Bacteria are sometimes named according to their shape: bacilli cocci spirilli

  25. Bacterial shapes:

  26. B. GRAM STAINING: • Most species of Eubacteria can be grouped into TWO Categories based a laboratory technique called GRAM STAINING. • TAXONOMISTS divide Eubacteria into • GRAM-POSITIVE bacteria • GRAM-NEGATIVEbacteria.

  27. Gram-stain technique • Hans Christian Gram, a Danish Microbiologist, developed a way to stain bacteria in 1884. (1)-STAIN slide of bacteria w/ PURPLE DYE (Crystal Violet) (2) IODINE,  (3) RINSE WITH ALCOHOL.  (4)Then Restained with A PINK DYE (Safarinin).

  28. Gram Stain Steps

  29. 2. KINGDOM EUBACTERIA 2 ways Bacteria Cell Walls Stain: Depending on Structure of the CELL WALLS, THE BACTERIA ABSORB EITHER THE PURPLE DYE OR THE PINK DYE. Gram-Positive Bacteria retain the PURPLE DYE and appear Purple. Gram-Negative Bacteria will appear PINK from the PINK DYE.

  30. 2. KINGDOM EUBACTERIA GRAM POSITIVE BACTERIA • Have a thick layer ofPEPTIDOGLYCAN(a protein-sugar complex) that adsorbs the purple color stain. • Some Gram-positive bacteria are • Beneficial organisms • But some cause DISEASE.

  31. 2. KINGDOM EUBACTERIA Gram stained bacteria: Which is gram positive & which is gram negative?

  32. Examples ofGram+ Bacteria: • Helpful: • Lactobacillus-make yogurt, pickles and buttermilk. • ACTINOMYCETES, are used to make ANTIBIOTICS, • Harmful : • cause many HUMAN DISEASES, INCLUDING SCARLET FEVER, STREP THROAT, TOXIC SHOCK SYNDROME, & PNEUMONIA. • Many produce TOXINS, which are poisons to our bodies

  33. Botulism • The most deadly toxin known is produced by Clostridium botulinum  (Botulism) • This is that same chemical that is used in “BOTOX” injections http://img.dailymail.co.uk/i/pix/2008/03_02/botoxDM1003_468x708.jpg

  34. GRAM-BACTERIA • An extra layer of lipidoutside the cell wall keep these bacteria pink (they don’t turn purple) after staining. They do absorb the PINK Stain, so they are easily distinguished with a microscope. • The extra lipid layer also stops many ANTIBIOTICS from entering the bacteria.  Treatment for these requires a different ANTIBIOTIC than those used for infections caused by Gram-positive bacteria.

  35. 2. KINGDOM EUBACTERIA C. Some Interesting Phyla of Bacteria: • There are up to 12 phyla of bacteria, including the following: • CYANOBACTERIA • SPIROCHETES • GRAM-POSITIVE BACTERIA • ENTERIC BACTERIA • CHEMOAUTOTROPHS • NITROGEN-FIXING BACTERIA

  36. 1. PHYLUMCYANOBACTERIA • Gram- negative • photosynthetic bacteria. • They are much LARGER than many other prokaryotes, and because they produce oxygen and provide food for other organisms they play an important rolein manyEcosystems. • Once classified as blue-green Algae

  37. Roles of Cyanobacteria: • Good: They work with Nitrogen fixing bacteria • Bad:Some Cyanobacteria (Anabaena) thrive on Phosphates & Nitrates that accumulate in Water.  • The Sudden Increase in the # of Cyanobacteria due to High availability of nutrients is called EUTROPHICATION or POPULATION BLOOM. • The Cyanobacteria DIE and are Decomposed by Heterotrophic Bacteria.  • The increasing populations of Heterotrophic Bacteria consume available Oxygen in the water, causing other organisms in the water, such as fish, to DIE from Lack of Oxygen. • Eutrophic lakes look green, murky, sludgy.

  38. A Eutrophic lake

  39. 2. PHYLUMSPIROCHETES • Gram-Negaitive • Spiral-Shaped • Heterotrophic • move by means of a corkscrew-like rotation. • Spirochetes live Freely, Symbiotically, or Parasitically. • Example: Treponema pallidum, which causes the sexually transmitted diseaseSyphilis.

  40. 3. PHYLUM GRAM-POSITIVEBACTERIA • Members of this Phylum include the species: • Streptococcithat causes Strep Throat • Lactobaccilli- Milk becomes Yogurt when these bacteria produce Lactic Acid. • ACTINOMYCETES (soil bacteria)  • Produce ANTIBIOTICS,chemicals that Inhibit the Growth of or Kill other Microscopic Organisms.

  41. 4. PHYLUM ENTERICBACTERIA • Inhabit Intestinal Tracts • live in either Aerobic or Anaerobic conditions. Examples: • The well known organism Escherichia coli (E. coli). lives in • human intestines - produces Vitamin K & Enzymes in Breakdown of food. • Also : Salmonella- responsible for Food Poisoning.

  42. 5. Phylum CHEMOAUTOTROPHS • Gram-negative bacteria- extract Energyfrom Minerals by Oxidizing the Chemicals in these Minerals. • Important in deep ocean vent ecosystems as primary producers where they use sulfur. Scientists are beginning to understand their importance in deep cave formations. • Basically , these are “mineral or rock eating” bacteria.

  43. 6. NITROGEN-FIXING BACTERIA • RHIZOBIUMare Gram-Negative bacteria that grow Symbiotically in root nodules of legume plants such as soybean, beans, peas, clover, and alfalfa. http://academic.reed.edu/biology/Nitrogen/images/part1/bigFL1.jpg

  44. Nitrogen fixing bacteria • The Earth's atmosphere is 78% NITROGEN (N2), but plants and animals cannot use nitrogen in its gaseous state.  • Nitrogen-fixing bacteria convert gaseous nitrogen into compounds such as AMMONIA. (We require Nitrogen to make nitrogen-containing compounds like Proteins and Nucleic Acids. ) • No other Kingdom includes organisms that can fix nitrogen.   Without nitrogen fixers, the diversity of life on our planet could not exist. WE CANNOT LIVE WITHOUT BACTERIA!!!

  45. IV. Bacteria & Humans Many of us only think of bacteria as the germs that cause DISEASE. • The scientific study of disease is called PATHOLOGY. • Bacteria that cause disease are called PATHOGENS.

  46. BACTERIAL DISEASES

  47. ANTIBIOTICS Antibiotics are Drugs that Fight Bacteria by interfering with their Cellular Functions. Many Antibiotics are derived from chemicals that Bacteria or Fungi Produce. TYPES: • PENICILLINinterferes with Cell Wall Synthesis. • TETRACYCLINE interferes with Protein Synthesis. • SULFA DRUGS are Antibiotics that are Synthesized in Laboratories. (Man Made) • Many Antibiotics are able to affect a Wide Variety of Organisms, they are called BROAD SPECTRUM ANTIBIOTICS.

  48. How antibiotics work: • The cell wall is the main target for many antibiotics • A major threat to humankind is the evolution of antibiotic-resistant strains of bacteria. • These have been artificially selected for by overuse of antibiotics.

  49. ANTIBIOTIC RESISTANCE • When a population of bacteria is exposed to an Antibiotic, the Most susceptible DIE.  A Few Mutant bacteria that are resistant to the Antibiotic may continue to grow. • A Resistant Population then grows from these Mutant Bacteria through reproduction and genetic recombination. • These new Population are Antibiotic-Resistant.  This has resulted from the Over Use of Antibiotics.  Many diseases that were once easy to treat are becoming more difficult to treat.

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