Bacteria: classification staining Nutrition recombination

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

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!

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)

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

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

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)

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.

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

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

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

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

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

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

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!

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

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.

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

Nutrition + Growth

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.

Photoautotrophs Use the sunlight as an energy source . cyanobacteria

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

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

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 6.5- 7[Neutral] Lactobacilli (yoghurt, Sour cream) prefer acidic environments (ph6 or lower)

Genetic recombination

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

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

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

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