OPTION F: MICROBES AND BIOTECHNOLOGY

IB BIO

IMPORTANT BUSINESS- Internal Assessment

- Should finish experimental trials by THURSDAY 30 JAN - If you need to schedule time with the instruments, please

sign up on the sheet on the door- Final Drafts due FRIDAY 7 FEB

- Quiz – Diversity of Microbes

- Next Wednesday! 29 JAN

MICROBES & BIOTECHNOLOGY- Diversity of microbes

- The nitrogen cycle

- Sewage treatment

- Beer, wine, and bread

- Gene therapy

- Disease and Epidemiology

DIVERSITY OF MICROBES

Objectives for today:

- Differentiate between the 3 domains of microbes

- Be able to identify gram-positive vs gram-negative bacteria

- Understand why single-celled organisms form clusters

DIVERSITY OF MICROBES

All living things can be classified into 3 different domains

1. Eubacteria

2. Archaea

3. Eukaryota

Image: http://www.learner.org/courses/envsci/visual/img_lrg/common_ancestor.jpg

EUKARYOTA- Most “complex” organisms

- Usually have larger genomes

- Only domain to have genes with introns- Largest ribosomes: 80s

EUBACTERIA- These are the single-celled organisms you are most

familiar with

- Have cell walls made of peptidoglycan

- 70s ribosomes

- Have no histone proteins

ARCHAEA- Formally classified in the same domain as eubacteria

- Single-celled organisms that look and act almost identical to eubacteria

- Cell membranes have different biochemical structure

- Eukaryotes/Eubacteria have ester bonds in membrane lipids

- Archaea have ether bonds in membrane lipids

ESTER VS ETHER LINKAGES

Image: http://classconnection.s3.amazonaws.com/865/flashcards/553865/png/ester_vs_ether1306815819523.png

ESTER VS ETHER LINKAGES

Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg

ESTER VS ETHER LINKAGES

Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg

ARCHAEA- 70s ribosomes (same as eubacteria)

- Genes do not contain introns

- Some species have histone proteins

- Occupy extreme environments

Image: wikimedia.org

Image: ucmp.berkely.edu

XXXTREME ARCHAEA- Halophiles

- Live in habitats with extremely high salt content- Found in saline lakes, e.g. Dead Sea

- Thermophiles

- Live in very hot habitats, up to 100C in some cases- Hot springs, volcanic areas, geothermal vents (black

smokers)- Methanogens

- Live in anaerobic habitats where organic matter is available

- Swamps, waterlogged soils, gut of cattle, landfills

DISTINGUISHING THE THREE DOMAINSCharacteristic Archaea Eubacteria Eukaryota

Are cell walls made of peptidoglycan?

What are the bonds in membrane lipids?

What size are the ribosomes?

Do most genes contain introns?

How many species have histone proteins?

DISTINGUISHING THE THREE DOMAINSCharacteristic Archaea Eubacteria Eukaryota

Are cell walls made of peptidoglycan?

None All None

What are the bonds in membrane lipids?

Ether Ester Ester

What size are the ribosomes?

70s 70s 80s

Do most genes contain introns?

No No Yes

How many species have histone proteins?

A few None All

DIVERSITY OF EUBACTERIA

DIVERSITY OF EUBACTERIA

1) Coccus: spherical bacteria

2) Baccilus: rod-shaped bacteria

3) Vibrio: comma-shaped rods

4) Spirilli: twisted bacteria

Some bacteria can group together to form AGGREGATES:Prefix “strepto-” form filamentsPrefix “staphylo-” form clusters

Ex. Staphylococcus form spherical clusters

COOPERATING BACTERIA – POWER TO THE PROLETARIAT MASSES

Biofilm a surface-coating colony of organisms

Pseudomonas aeruginosa produces biofilms in burned patients and in patients with cystic fibrosis. It is easier for bacteria to acquire resistance to antibiotics b/c they can cooperate and interact in different ways

COOPERATING BACTERIA – POWER TO THE PROLETARIAT MASSES

Autoinducers help coordinate the action of a group of bacteria

Vibrio fischeri is a bacterium found in sea water than is able to emit light in a process called bioluminescence. Individuals do not emit light unless they become part of a population of certain density.

V. fischeri releases an autoinducer into its surroundings. In a dense population, the concentration of the inducer becomes high enough to trigger bioluminescence.

Image: bioart.co.uk/lux/vib.jpg

ASSIGNMENT

Find one example of an archaea, eubacteria, and eukaryota that you find interesting and create a 3-6 slide powerpoint with the following:

1) Scientific name

2) Habitat/Growing conditions

3) Shape (e.g. coccus, bacillus)

4) Gram-positive or negative (if eubacteria)

5) At least one picture

6) E.C. available for going above and beyond the call of duty

DISTINGUISHING EUBACTERIA - GRAM STAINING- Eubacteria can be classified into 1 of 2 categories based

on their cell wall structure:

- Gram-positive (thick peptidoglycan cell wall)- Gram-negative (thin peptidoglycan cell wall, thin outer

layer of lipopolysaccharide and protein)

- Using a series of chemicals, we can identify the cell wall structure of eubacteria by the color they stain

- Gram-positive stains purple (POSITIVELY PURPLE)- Gram-negative stains red

Image: http://pathmicro.med.sc.edu/fox/gram-st.jpg

GRAM- VS GRAM+

Image: http://4.bp.blogspot.com/gramposandneg.jpg

EXAMPLE OF GRAM STAINED EUBACTERIA

Image: wikipedia.org