1. Bacteria: classification staining Nutrition recombination

2. We looked at how to describe bacterial colonies and make purity plates for our specimens
Looked at the different structures of bacteria, and briefly at classification
What is the difference between Gram Positive and Gram Negative?
The amount of peptidoglycan in the…
Cell wall
Reminder, all retests must be done by Wednesday, April 22!!
Last Day

3. Outlook for Today Further look at bacterial classification
Gram staining procedure
Gram staining our organisms!
Bacterial Nutrition
Recombination and Replication
Time permitting: observing our Gram stains!

4. Outlook for Future Antibiotic resistance talk – April 23rd
Bacteria Unit Test – Tentatively May 1
Term Reports Due Friday – Please have all assignments you want updated for this term done by THURSDAY
Evol/DNA retests – Today or tomorrow!
Virus Retest – Wednesday or Thurs!
Bacteria Quiz – structure, media, nutrition, classification, recombination MONDAY, APRIL 27. (FOR MARKS)

5. Bacterial classification
Last Day – We learned about the difference between Gram positive and Gram negative organisms
But we can classify bacteria even further

6. Kingdom Eubacteria
There are 12 different phyla of bacteria according to evolutionary relationships
There are only 4 we will be focusing on in this unit
Table 24-1 in your textbook
Cyanobacteria
Spirochetes
Gram-positive bacteria
Proteobacteria

7. Phylum Cyanobacteria Once known as Blue-green algae
Now classified as Eubacteria, as they do not contain any membrane bound organelles
Photosynthetic (Use sunlight to produce energy, give off oxygen as a waste product) prokaryotes
Responsible for the oxygen in Earth’s atmosphere today!
Can grow in chains and form heterocysts
Used to fix Nitrogen (converting atmospheric Nitrogen into ammonia for use by plants)

8. Phylum Cyanobacteria
An accumulation of nutrients (nitrates and phosphates) can lead to an overgrowth of cyanobacteria known as eutrophication or population/algal bloom
Following eutrophication, many cyanobacteria die off and are decomposed by heterotrophic bacteria
Heterotrophic bacteria consume available oxygen in water, causing other marine life to die.

10. Phylum Spirochetes Gram positive Spiral shaped Heterotrophic
Cannot fix carbon, must use organic carbon for growth
Aerobic or Anaerobic
Grow in presence of oxygen or in absence of oxygen
Move in cork-screw like rotation

11. Phylum Spirochetes Treponema pallidum
Can live:
Freely
No need for host organism
Symbiotically
Lives on/in host organism, both organisms benefit from relationship
Parasitic
Live on/in host organism, only bacterium (parasite) benefits, while causing harm to host
Syphyllis
Phylum Spirochetes Treponema pallidum

12. Phylum Gram Positive Bacteria Streptococcus sp.
Despite it’s name… not all members in this phylum are Gram positive
Some GN organisms in this phyla because of their molecular similarities
Actinomycetes
GP bacteria that produce many of the antibiotics we know today
Many human infections
Staphylococcus
 Streptococcus

13. Phylum Gram Positive Bacteria Lactobacillus sp.
Grows in all of us!
Makes milk turn into yoghurt
Found in our oral cavity and intestinal tract
Help with oral health… but can also be associated with tooth decay

14. Phylum Proteobacteria
Gram Negative bacteria
Can be
Enteric
Chemoautotrophs
Nitrogen Fixing bacteria

15. Enteric Bacteria Inhabit animal intestinal tracts Escherichia coli
Produces Vitamin K, and assists with breakdown of food
Salmonella spp.
Responsible for many cases of food poisoning

16. Chemoautotrophs Extract energy from minerals, by oxidizing them.
Iron-oxidizing bacteria
Grown in high iron concentration lakes
Can be used in bio-mining
More on that later!

17. Nitrogen fixing bacteria
Produce Nitrogen (N2) – the primary gas in our atmosphere!
Live on many types of plants – plants provide them with nutrients, bacteria provide plants with forms of nitrogen they can use
What kind of relationship do we call this?
Symbiotic

18. To do now: Gram stain instruction lecture
½ of class – Work on 24.1/24.2/finish off notes Review Silently, so classmates can focus on gram strain procedure
Switch after first group is done.

19. To do now: With your partner
CAREFULLY follow the Gram stain procedure provided for you.
When done, you can read ahead in 24.2

20. Nutrition + Growth

21. Heterotrophs and autotrophs
Use organic matter as a source of nutrition
Saprophytes
Feed on dead and decaying material
Autotrophs
Obtain their energy from sunlight or minerals.

22. Photoautotrophs
Use the sunlight as an energy source .
cyanobacteria

23. Chermoautotrophs
As we have just learned, oxidize inorganic minerals to obtain energy

24. Living Environments Obligate anaerobe
CANNOT live in the presence of oxygen
Clostridium tetani (causes tetanus)
Facultative anaerobes
Can live with or without oxygen
E.coli
Obligate aerobes
Cannot survive WITHOUT Oxygen
Mycobacterium tuberculosis (causes tuberculosis [TB])
Living Environments

25. Temperature Requirements
Different species of bacteria grow best at all different temperatures
Most grow best in 30-35oC range
Thermophillic bacteria grow best in high temperatures (40-110oC)
Most bacteria grow best at pH [Neutral]
Lactobacilli (yoghurt, Sour cream) prefer acidic environments (ph6 or lower)

26. Genetic recombination

27. Table 24-3 in text
Ways bacteria can acquire and express new genetic information

28. Transformation
When a bacterial cell takes in DNA from the external environment.
New material substitutes out existing, similar material and becomes part of the bacterial chromosome

29. Conjugation
Bind together, one bacteria can exchange genetic information with another
Genetic Donor must contain special plasmid and pillus
Binds to recipient bacterium, forms a conjugation bridge
Plasmid replicates in donor cell, then replicated plasmid transfers over conjugation bridge into recipient cell
After DNA transfer, cells detach

30. Transduction Bacteria and viruses working together!
Virus takes up fragments of bacterial DNA.
After Virus replicates, and is released, it will find new bacteria to transfer DNA into.
Old bacterium's genes can be expressed in new bacteria