SC246: Microbiology

1. SC246: Microbiology Fundamentals of Microbiology SC 246 Unit 1 Seminar Luis Lowe 404-981-6570 LLowe@kaplan.edu AIM account: Luis.Lowe

2. About Me • MS Biology and Maters in Public Health • Work at Centers for Disease Control in Atlanta, Georgia • Bioterrorism agents • Molecular Assays, epidemiology, etc… • Instructor for Microbiology, General Biology and Anatomy and Physiology • Science Geek • Into fitness and nutrition • Questions

3. Agenda tonight • Course overview • Syllabus, Grading, How to, • Answers for those new to online • Email address should be Kaplan • IMPORTANT NUMBER 877-623-0272 • Eukaryotic vs. Prokaryotic • What in the world does that mean? • Bacteria • Walls • Gram stains • Science center tour at 8:45 • Questions

4. Prokaryotic –Eukaryotic Cells • Comparing Prokaryotic and Eukaryotic Cells • Prokaryote comes from the Greek words for prenucleus. • Eukaryote comes from the Greek words for true nucleus. • What do the terms Prokaryotic and Eukaryotic mean? What are some of the major differences between Prokaryotic and Eukaryotic cells?

5. Prokaryote Eukaryote • Paired chromosomes, in nuclear membrane • Organelles • Simple cell walls (IF present) • Mitosis • One (usually) circular chromosome, not in a membrane • No membrane-enclosed organelles • Peptidoglycan cell walls (usually) • Binary fission

9. Question to think about? • From an evolutionary prospective, Prokaryotic cells are much less complex than Eukaryotic cells. It seems that we wouldn’t have much of a problem fighting them off, right? However, this is obviously not the case. Offer an explanation for this. WHY do you think we still get infections and illnesses?

12. Gram stain • What is it? What is it used for? • The Gram stain was developed by Christian Gram in 1884 • Primary stain of identification in microbiology lab • Used to classify bacteria as either gram positive or gram negative. What does that mean? • Most, but not all, bacteria can be stained using this method • Which one(s) can’t. • Why does it stain differently? • Why is it a fundamental part of identifying bacteria? What are the major differences between Gram negative and Gram positive cells?

14. Gram Stain Mechanism • Staining procedure: 1.Crystal violet and Gram’s iodine: Primary stain 2. Stain is decolorized with 95% ethanol 3. Counterstain: Safranin 4. Water rinse Gram + retain CV and remain purple Gram – retain safranin * Based on cell physiology

17. Figure 4.13b, c

18. Differential Stains: Gram Stain Figure 3.11b

19. Gram +Streptococcus Pyogenes(What is strep pyogenes?) Other clinically relevant Gram +?

20. Gram-positive cell walls • Thick peptidoglycan • Teichoic acids • In acid-fast cells, contains mycolic acid Gram Stain Anthrax

21. Gram - • Spirillum volutans (harmless bacteria) Other clinically relevant Gram -?

22. Gram-Negative Outer Membrane • Lipopolysaccharides, lipoproteins, phospholipids. • Forms the periplasm between the outer membrane and the plasma membrane. • Protection from phagocytes, complement, antibiotics. • O polysaccharide antigen, e.g., E. coli O157:H7. • Lipid A is an endotoxin. • Porins (proteins) form channels through membrane

23. Something to think about? • The medical and scientific communities use their knowledge of Prokaryotic cells to target infectious microbes and clear out infections. Given just what you have learned so far, how do you think they might go about this?

24. KU Science Center Tour • Go to the following link • http://khe2.adobeconnect.com/kusc_tour/ • Afterwards, you are free to go • Email with any questions you may have.

25. Questions??

26. References • Tortora, G., Funke, B., & Case, C. (2007). Microbiology: An Introduction (8th ed.). San Francisco, CA: Pearson.

27. Peptidoglycan • Polymer of disaccharideN-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM) • Linked by polypeptides Figure 4.13a

30. Gram-Positive cell walls • Thick layer of peptidoglycan Figure 4.13b

31. Gram-Negative Outer Membrane Figure 4.13c