Lecture 6: Extremophiles Flashcards
What extreme conditions make extreme habitats?
- Temperature
- Pressure
- Salinity
- pH
- Radiation
Match the extremophile to their extreme habitat.
- Temperature
- Pressure
- Salinity
- pH
Halophiles
Barophiles
Thermophiles, psychrophiles
Acidophiles, alkaliphiles
- Thermophiles, psychrophiles
- Barophiles
- Salinity
- Acidophiles, alkaliphiles
List examples of natural and man-made thermophilic habitats.
- Natural
- Geothermally heated oil
- Geothermal and volcanic areas
- Hydrothermal vents - Man-made
- Acid mine drainage
- Biological wastes
- Self-heated compost piles
What temperatures can white smokers vs. black smokers reach? What is the temperature of sea water?
- White smokers: up to 73ºC
- Black smokers: up to 400ºC
- Sea water: 2ºC
What feeds chemoautotrophic bacteria in the ocean?
The chemical laden water escaping from cracks in the seafloor around the mid-ocean ridges
Which type of smoker is the most common type?
Black smokers
What causes the black chimneys in black smokers?
- Black color is caused by the presence of iron and sulfur
- When the iron monosulfide solidifies, it creates the black chimneys
Black smokers are _____ while white smokers are _____.
(hotter/coolor)
- hotter
- cooler
What causes the white chimneys in white smokers?
- Contain more barium, calcium, and silicon
- Create white chimneys, which are usually smaller than black chimneys
What do the arrows in the food web represent?
Arrows point in the order of energy transfer
List some terrestrial sulfuric environments.
- Fumaroles
- Geysers
- Hot springs
What is the temperature and pH of hot springs?
- Temp up to 100ºC
- pH 1-12
What are the temperature ranges for thermophiles vs hyperthermophiles?
- Thermophiles: 50-80ºC
- Hyperthermophiles: >80ºC
What habitats do psychrophiles/psychrotolerants live in? (Hint: cold)
- Deep ocean: 75% of Earth’s volume
- Sea-ice: polar regions
- Antarctica
What are the optimal temperatures for psychrophiles vs. psychrotolerants?
- Psychrophiles: 15-20ºC
- Psychrotolerants: >20ºC
What temperature adaptations have extremophiles developed?
-
Lipids
- Thermo: saturated, longer FAs –> maintain structure
- Psychro: unsaturated, shorter FAs –> stay fluid - Higher GC content: encodes thermostable amino acids (higher temp environments)
- Chaperonins (heat/cold shock proteins)
-
Enzyme activity: used as a measure of how quickly things will degrade
- Increased enzyme variability allows them to still be functional with a 10º change in temperature
Barophiles function under _____ pressure.
higher
List some barophilic organisms.
- Colwellia
- Shewanella
- Moritella
Why are barophiles difficult to cultivate?
Cultivation requires maintenance of high pressure for many
- Usually need low temp and low light
Which of the following are adaptations you would NOT expect to see in a polar, deep-sea bacterium?
A. Unsaturated lipids
B. Short-chain fatty acids
C. Chaperonin proteins
D. Saturated lipids
A. Unsaturated lipids
B. Short-chain fatty acids
C. Chaperonin proteins
D. Saturated lipids
What are 2 hypersaline environments?
- Evaporative salterns, lakes, and ponds
- Brines - Antarctice brine ponds
- Freezing mimics evaporation
- >35 ppt salts
What do thalassohaline and athalassohaline mean?
- Thalassohaline = derived from seawater
- Athalassohaline = salts derived from geology of terrestrial habitat
What are some examples of athalassohaline environements?
- Dead Sea
- Great Salt Lake
What are some organisms that can live in extreme hypersaline environments?
- Eukaryotic
- Dunaliella: green algae - Archaea
- Haloarcula, Halorubrum,
Haloquadratum - Bacteria
- Halomonas, Salinivibrio,
Cyanobacteria
Give an overview of halophile physiology.
1. What stabilizes the cell wall?
2. What are the compatible solutes?
3. What is the function of bacteriorhodopsin pigments?
4. What is the function of carotenoids?
- Na+ stabilizes cell wall
- Compatible solutes
- Archaea: ~5 M K+ actively pumped in from water
- Bacteria: glycine-betaine, trehalose syntheiszed - Absorbs light
- Protects cell DNA from UV induced radicals
List acidic habitats.
- Hot springs
- Volcanic soils
- Mining (acid-mine drainage)
What are some acidophilic microbes?
- Fungi: generally more acidophilic than prokaryotes
- Algae
- Cyanidium (red alga)
- Zygogonium (green alga) - Archaea
- Picrophlius
- Sulfolobus - Bacteria
- Thiobacillus
- Leptospirillum
List alkaliphilic habitats.
Soda lakes (pH ~10; bicarbonate and sodium rich)
- Ex. East Africa Rift Lakes
- Ex. Mono Lake, CA
What are some alkaliphilic microbes?
- Archaea
- Natronobacterium
- Natronococcus - Bacteria
- Cyanobacteria
- Gram-positives (ex. Bacillus, Clostridium)
Give an overview of acidophilic/alkaliphilic physiology.
1. What is their internal pH usually? How low/high can be sometimes?
2. What stabilizes the membranes?
3. how do they generate proton motive forces?
- Usually ~neutral, but may be as low as 2-3 and upwards of 8-9
- Protons are used to stabilize membranes in acidophiles
- Na+ is substituted for some purposes in both acidophiles and alkaliphiles
Changes in the use of ions for important structural or metabolic processes are important for which of the following habitats?
A. Hydrothermal
B. Hypersaline
C. Acidic
D. Both A & B
E. Both B & C
What is the importance of microbial mats? How do microbial mats create biogeochemical gradients?
- Forms a consortium of various metabolisms
- Create biogeochemical gradients by each layer providing resources for the layer below it
What is the role of acidithiobacillus in caves?
Help dissolve limestone enlarging the cave
How do cave microbes retrieve energy?
Through oxidation of inorganic molecules
How do cave bacteria acquire carbon?
By accessing hydrocarbons in speleothems
