Microbiology

1. Microbiology

2. Bacteria • -the most numerous and most ancient organisms on Earth in 1998, estimated at 5 million trillion http://www.ehow.com/about_4674401_how-many-bacteria-live-earth.html • -unicellular prokaryotes phschool.com

3. Classification • -2 Kingdoms -based on ribosomal RNA differences • -Eubacteria : common germs ex: E. coli, Salmonella • -Archaebacteria: ancient bacteria that live in extreme conditions ex: Thermusaquaticus

4. Archaebacteria • differences from eubacteria: • introns in DNA • no carbohydrate in cell wall • extra lipids in cell membranes, • archaebacteria genes are more similar to eukaryotic genes than eubacteria, • non-pathogenic

5. Types of archaea • 1. Methanogens -harvest energy by converting H2 and CO2 into methane gas (CH4) -O2 poisons them only live in anaerobic conditions such as in sewage, swamps, intestines microimm.queensu.ca

6. 2. Extreme halophiles -use high levels of salt to make ATP -found in Great Salt Lake, Dead Sea • 3. Thermoacidophiles -live in extremely acidic, hot environments  pH <2, temps up to 230 F - found in volcanic and hydrothermal vents (p. 469) http://www.daviddarling.info/encyclopedia/H/halophile.html Salt flats at Lake Magadi, Kenya. The flats are red due to the proliferation of halobacteria

7. Making cultures -Liquefy nutrient agar and pour into sterile petri dishes while warm -Store in refrigerator until ready ~ 1 hour before use -use a sterile cotton swab or inoculating needle and swab your sample -Very gently rub the swab over the agar in a few zigzag strokes and replace the lid on the dish & tape it shut -incubate for 3-7 days around 37 C.

8. Eubacteria • most bacteria, some are pathogenic • 3 basic shapes bacilli (rods), cocci (spheres), spirilla (spiral) • types of eubacteria • Cyanobacteria, Spirochetes, Gram +, Proteobacteria • posters, p. 472-3

9. Gram Stain • way of classifying bacteria, based on retention of purple stain due to a thick layer of peptidoglycan carbohydrate in their cell wall in gram + • React to different antibiotics & disinfectants • often the 1st test done on pathogens

10. -Gram positive withstands dessication better (so can live in non-moist enviro. like skin) , generally killed by penicillin • -Gram negative killed by drying, thrive in moist enviro, can withstand chemicals like chlorine, more resistant to antibiotics

11. How to Gram stain spread some bacteria on a slide fire it by passing the slide through a flame briefly flood the slide with crystal violet solution for 1 minute add iodine solution for 3 minutes - at this stage all cells are purple Add alcohol for 20 seconds 6. Stain with safranin This results in gram positive cells remaining purple and gram negative ones being red or pink. earlham.edu

12. Bacterial structure • (almost) All have • Cell wall, plasma membrane, cytoplasm, circular chromosome, ribosomes

13. Some have  • plasmids • capsules • pili • endospores • flagella

14. Find & put into a ppt slide • What they are made of • Their function • How they work • pictures

15. Some have  • Plasmids: extra, self-replicating DNA -not crucial for cell survival, can carry genes that help in certain conditions (such as ab resistance) -can be transferred from bacterium  bacterium • capsules: protective outer coverings, protect from white blood cells • pili: short, hairlike proteins to help w/adhesion • endospores: have protective covering to resist extreme conditions (like boiling & freezing) • Released from cell, can remain dormant for thousands of years • Flagella: whiplike tails for movement

16. -Cell wall function: provides shape for cell, protects against outside environment, prevents cell from rupturing when there is high water pressure in the cell, anchorage for flagella -made of peptidoglycan -Gram + have many layers, gram – few -cell membranes of gram- provide a barrier against antibiotics

17. Pic of cell wall

18. Pics of flagella, pili, plasmids ict-science-to-society.org leisureguy.com cosmology.net

19. Bacterial Cell Wall • It is made of: peptidoglycan and teichoic acid • Their function: it maintains the overall shape of the bacteria cell. Its an anchor for the phili and flagella. It contains the organelles and helps keep the cell wall from bursting. • Antibiotics that target the cell wall can get rid of the bacteria.

20. Bacteria Membrane Made up of proteins, lipids, and polysaccharides (1) Acts as a barrier that allows nutrients in and harmful substances out (2) used to attach or adhere to specific surfaces or tissues (3) Enzymes take care of surface reactions important to cell survival (4) protective structures against host defenses (5) antigenic disguises to bypass activation of host immune defenses; (6) Endotoxins that cause an inflammation in the host (7) proteins that can respond to temperature, salinity, light, oxygen, nutrients Most functions are taken care of by the hydrophobic layer of lipids that allow things in or out of the cell and the polysaccharides on the outer layer

21. Pili [pee-lee] -Connect a bacterium to another of its species, or to another bacterium of a different species, and build a bridge between the interior of the cells. -Enables the transfer of plasmids between the bacteria. -They are antigenic (any substance that can stimulate the production of antibodies and combine specifically with them. ) [dictionary.com] -Fragile and consistently replaced -Hair-like structure, often many on one bacteria -Shorter than flagella, very thin -made up of a long chain protein or polysaccharide http://en.wikipedia.org/wiki/Pilus#Pilihttp://www.daviddarling.info/encyclopedia/P/pilus.html

22. ENDOSPORES • Endospores consist of the bacterium's dna and part of its’ cytoplasm. • These endospores are released to protect the bacteria. • When the bacteria detects environmental hazards it releases an endospore for safety. • Endospores are resistant to ultra violet light, dessication, high temperature, and many other things.

23. Are circular self-replicating organelles in the cell, of bacteria, that hold a small amount genetic information. • Organisms usually have the same amount as the generation before them • They are the foundation of recombinant DNA • Bacteria are able to exchange information with one another using these plasmids causing mutations. • They are separate from the chromosomal DNA; they only hold a few genes. Plasmids (ORI)- origin of replication Made of three main parts: A cloning site or place of insertion of DNA An origin of replication A selectable marker gene http://escience.ws/b572/L2/L2.htm http://askabiologist.asu.edu/plasmids

24. Flagella Prokaryotes: protein flagellin Allow bacteria to move Flagella have hooks that can turn and propel the organism When the flagella rotates clockwise, the bacteria can fall or tumble

25. Metabolism • the sum of all chemical reactions in an organism • Weight of a bacterium= 50% carbon, 14% nitrogen, 4% sulfur & phosphorus • heterotrophicmicrobes use organic substances ,esp. glucose to make energy

26. Metabolism • http://player.discoveryeducation.com/index.cfm?guidAssetId=E7965B93-1D6D-4740-8C55-D6E80EDB4C49&blnFromSearch=1&productcode=US# • All go through glycolysis • Availability of oxygen determines next step • Aerobes cellular respiration = higher ATP yield due to Krebs cycle & ETC, aerobic • oxygen as final e- acceptor, lots of ATP= fast growth • Anaerobicfermentation= little ATP produced, creates alcohol and lactic acid, anaerobic -final e- acceptor not oxygen, often nitrate, little ATP= slower growth • table

27. Autotrophs make organic compounds from CO2 or other inorganic molecules • Chemotrophs get energy from electron donors in their environments (chemicals) -glucose, acetate, etc. or inorganic chemicals H2, H2S, Fe, NH4, etc. . Phototrophs- convert solar energy into ATP

28. Measuring Microbes • Serial dilution • a set of dilutions with several steps in which each step has the same dilution factor- usually 10 • each time, the sample get 10 times less diluted as the previous one • http://www.professorcrista.com/bio_205_animations.htm

29. How to do a serial dilution • 1. set out a series of tubes with 9mL of buffer water (suitable for bacteria) • 2. Draw up 1mL from the original sample and put it in the first 9mL buffer. This is a 1 to 10 dilution which makes the sample exactly 10 times less concentrated as the sample. • 3. Then draw up 1mL from the first dilution tube and put it in the second tube. This is another 1 to 10 dilution which makes the sample exactly 10 times less concentrated as the first tube and 100 times less concentrated as the original sample. • 4. Draw up 1mL from the 2nd tube and put it in the 3rdtube.This will be a 1: ____________dilution and so on…

30. Streak plate method • 1. Get a loopful of bacteria from a sample • 2. Streak the top 1/3 of the agar plate horizontally • 3. Sterilize loop • 4. Get some bacteria from 1st streak in loop • 5. Streak vertically ~1/3 of plate on right side • 6. Sterilize loop • 7. Get some bacteria from 2nd streak in loop • 8. Streak the bottom 1/3 of the plate horizontally • This should allow you to isolate colonies of bacteria

31. psu.edu

32. Reproduction • Binary fission • http://www.textbookofbacteriology.net/growth.html

33. Counting bacteria • http://www.microbiologybytes.com/LabWork/bact/bact1.htm • Viable count= # bacteria or clumps of bacteria per cm3

34. Evolution • Transformation -use plasmids to transfer DNA to other bacteria or other organisms lab

35. Bacteria & humans • Useful bacteria • Agriculture (n2 fixation), food (cheese, wine), biofuels ice nucleating lab • Disease • Antibiotics • A.b. lab

36. Viruses