BACTERIA CLASSIFICATION STAINING NUTRITION RECOMBINATION Last Day We

BACTERIA: CLASSIFICATION STAINING NUTRITION RECOMBINATION

Last Day • 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!!

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 23 rd • 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 • Once known as Blue-green algae – Now classified as Eubacteria, as they do not Cyanobacteria 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 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. • 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 (N 2) – 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 – Use organic matter as a source of and autotrophs nutrition • Heterotrophs – 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])

Temperature Requirements • Different species of bacteria grow best at all different temperatures – Most grow best in 30 -35 o. C range – Thermophillic bacteria grow best in high temperatures (40 -110 o. C) • Most bacteria grow best at p. H 6. 57[Neutral] – Lactobacilli (yoghurt, Sour cream) prefer acidic environments (ph 6 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