1. Domains: Bacteria Archea

2. Two Lineages Archaebacteria Eubacteria

3. Metabolic Diversity Photoautotroph Photoheterotroph Chemoautotroph Chemoheterotroph

4. Archaebateria Methanogens Extreme halophiles Thermoacidophiles

5. Archaebacteria have Different Characteristics They have unusual proteins They have introns within their mRNA. They lack peptidoglycan.

6. Eubacteria Most bacteria 2 basic types –Gram + –Gram -

7. Types of Cell Shapes Coccus Bacillus Spirillium Spirochete

8. Cell Groupings or singles or diplo orstrepto staphylo

9. Gram Staining Developed by the Danish bacteriologist, C. Gram, as a way to differentiate between bacteria. Divides bacteria into two groups based on their cell wall composition. –G (+) Single layered cell wall with a low lipid content. –G (-) 3 layered cell wall with a high lipid content.

10. Why a Gram Stain? To gain knowledge about a bacteria’s structure and grouping arrangements Taxonomic purposes Medical reasons –Doctors can use the Gram stain results to help properly diagnose and treat bacterial infections.

11. What can we tell about a bacteria’s structure? Cell shape Cell groupings Presence of endospores Cell wall content Approximate size

12. Presence of Endospores Endospores are found only in bacilli Central terminal

13. Cell Wall Composition Basis of the Theory behind the Gram Stain –G (+) bacteria retain the primary stain (crystal violet) because the decolorizer does not dissolve it’s cell wall (peptidoglycan) –G (-) bacteria lose the primary stain because the decolorizer dissolves a portion of the cell wall (lipopolysaccharide) releasing with the primary stain.

14. Here’s how it works.

15. Decolorization results in the high lipid content cell wall being washed away leaving the Gram (-) cell wall colorless.

16. Safranin (secondary stain) is then used to stain any cell walls left unstained after decolorization

20. Kingdom Eubacteria Phylum Cyanobacteria Phylum Spirochetes Phylum Gram-Positive Bacteria Phylum Proteobacteria

21. Phylum Cyanobacteria Photosynthetic Blue-green algae but considered eubacteria as they lack a membrane- bound nucleus and chloroplasts. Grow in chains. Some cells become specialized cells called heterocysts that have the ability to fix N 2.

22. Phylum Cyanobacteria (cont.) A sudden increase in the number of cyanobacteria in a body of water due to an increase in phosphates and nitrates is called eutrophication (population bloom). Can cause fish kill due to decay of cyanobacteria and lack of O 2 and nutrients.

23. Phylum Spirochetes Gram-(-), spiral-shaped heterotrophic bacteria Can be aerobic or anaerobic Corkskrew rotation Commensal, mutualistic, or parasitic. Treponema pallidum (syphilis)

25. Phylum Gram-Positive Bacteria Does include some G(-) bacteria. Includes Steptococcus (Strep throat) and Staphylococcus (sinus infections and boils). Lactobacilli responsible for tooth decay (secrete an acid). A gram positive converts milk into yogurt. Actinomycetes produce antibiotics. Are recognized by their branching filaments.

26. STAPHYLOCOCCUS INFECTION

28. Proteobacteria Enteric bacteria: Gr. - lives in the intestines e.g. Salmonella, E. coli Chemoautotrophs: Gram (-) bacteria that extract energy by oxidizing minerals e.g. Rhizobium (a N 2 fixing bacteria).