3. Lecture Aims
What are Extremophiles- an introduction
Strategies for growth & survival
Biotechnology
4. Introduction to Extremophiles
What are Extremophiles
Live where nothing else can
How do they survive?
Extremozymes (more details later)
Why are they are interesting?
Extremes fascinate us
Life on other planets
Life at boiling temperatures
Practical applications are interesting
Interdisciplinary lessons
Genetic Prospecting
5. Extremophile
Definition - Lover of extremities
History
First suspected in 1950’s
Extensively studied since 1970’s
Temperature extremes
Boiling or freezing, 1000
C to -10
C
Chemical extremes
Vinegar or ammonia (<5 pH or >9 pH)
Highly saline, up to x10 sea water
How we sterilize & preserve foods today
6. Extreme Temperatures
Thermophiles - High temperature
Thermal vents and hot springs
May go hand in hand with chemical extremes
Psychrophiles - Low temperature
Arctic and Antarctic
1/2 of earth’s surface is oceans between 1-40
C
Deep sea –10
C to 40
C
Most rely on photosynthesis
9. Chemical Extremes
Acidophiles - Acidic
Again some thermal vents & hot springs
Alkaliphiles - Alkaline
Soda lakes in Africa and Western U.S.
Halophiles - Highly saline
Natural salt lakes and manmade pools
Sometimes occurs with extreme alkalinity
13. Survival
Temperature extremes
Every part of microbe must function at
extreme
“Tough” enzymes for Thermophiles
“Efficient” enzymes for Psychrophiles
Many enzymes from these microbes are
interesting
Life at High Temperatures, Thomas M. Brock
14. Survival
Chemical extremes
Interior of cell is “normal”
Exterior protects the cell
Acidophiles and Alkaliphiles sometimes excrete
protective substances and enzymes
Acidophiles often lack cell wall
Some moderate halophiles have high concs of a
solute inside to avoid “pickling”
Some enzymes from these microbes are interesting
15. What are enzymes?
Definition - a protein that catalyses (speeds
up) chemical reactions without being changed
16. What are enzymes?
Enzymes are specific
Lock and key analogy
Enzyme
Substrate A
Product B
Product C
17. What are enzymes?
Activation energy
Enzymes allow reactions with lower energy
Energy
Time
Without Enzyme
With Enzyme
18. What are enzymes?
Enzymes are just a protein
They can be destroyed by
Heat, acid, base
They can be inhibited by
Cold, salt
Heat an egg white or add vinegar to milk
Protein is a major component of both-
denatures
19. Practical Applications
Extremozymes
Enzyme from Extremophile
Industry & Medicine
What if you want an enzyme to work
In a hot factory?
Tank of cold solution?
Acidic pond?
Sewage (ammonia)?
Highly saline solution?
20. One solution
Pay a genetic engineer to design a “super”
enzymes...
Heat resistant enzymes
Survive low temperatures
Able to resist acid, alkali and/or salt
This could take years and lots of money
22. Thermophiles
Most interesting, with practical applications
Many industrial processes involve high heat
450
C (113F) is a problem for most enzymes
First Extremophile found in 1972
Life at High Temperatures, Thomas M. Brock
23. PCR - Polymerase
Chain Reaction
Allows amplification of small sample of DNA
using high temperature process
Technique is about 10 years old
DNA fingerprints - samples from crime scene
Genetic Screening - swab from the mouth
Medical Diagnosis - a few virus particles
from blood
Thermus aquaticus or Taq
Life at High Temperatures, Thomas M. Brock
25. Acidophiles
Enzymes used to increase
efficiency of animal feeds
enzymes help animals
extract nutrients from feed
more efficient and less
expensive
Life at High Temperatures, Thomas M. Brock
26. Alkaliphiles
“Stonewashed” pants
Alkaliphilic enzymes soften fabric and
release some of the dyes, giving worn look &
feel
Detergents
Enzymes dissolve proteins or fats
Detergents do not inhibit alkaliphilic
enzymes
27. Halophiles
What is a halophile?
Diversity of Halophilic Organisms
Adptation Strategies
Osmoregulation-“Compatible Solute” Strategy
“Salt-in” Strategy
Interesting Facts and Applications
28. What is a halophile?
Halophile = “salt loving; can grow in higher salt
concentrations
Based on optimal saline environments halophilic
organisms can be grouped into three categories:
extreme halophiles,
moderate halophiles, and
slightly halophilic or halotolerant organisms
Some extreme halophiles can live in solutions of
25 % salt; seawater = 2% salt
29. Diversity of Halophilic Organisms
Halophiles are a broad group &t can be
found in all three domains of life.
Found in salt marshes, subterranean salt
deposits, dry soils, salted meats,
hypersaline seas, and salt evaporation
ponds.
30. Unusual Habitats
A Pseudomonas species lives on a desert
plant in the Negev Desert- the plant
leaves secretes salt through salt glands.
A Bacillus species is found in the nasal
cavities of desert iguanas- iguanas nasal
cavities have salt glands which secrete
KCl brine during osmotic stress.
31. Osmoregulation
Halophiles maintain an internal osmotic
potential that equals their external
environment.
Osmosis is the process in which water
moves from an area of high concentration
to an area of low concentration.
32. Osmoregulation
In order for cells to maintain their water
they must have an osmotic potential equal to
their external environment.
As salinity increases in the environment its
osmotic potential decreases.
If you placed a non halophilic microbe in a
solution with a high amount of dissolved salts
the cell’s water will move into the solution
causing the cell to plasmolyze.
33. Osmoregulation
Halophiles have adapted to life at high
salinity in many different ways.
Structural modification of external cell
walls- posses negatively charged proteins
on the outside which bind to positively
charged sodium ions in their external
environments & stabilizes the cell wall
break down.
34. “Compatible Solute” Strategy
Cells maintain low concentrations of salt in their
cytoplasm by balancing osmotic potential with
organic, compatible solutes.
They do this by the synthesis or uptake of
compatible solutes- glycerol, sugars and their
derivatives, amino acids and their derivatives &
quaternary amines such as glycine betaine.
Energetically synthesizing solutes is an expensive
process.
Autotrophs use between 30 to 90 molecules of ATP to
synthesize one molecule of compatible solute.
Heterotrophs use between 23 to 79 ATP.
35. “Salt-in” Strategy
Cells can have internal concentrations that
are osmotically equivalent to their external
environment.
This “salt-in” strategy is primarily used by
aerobic, extremely halophilic archaea and
anaerobic bacteria.
They maintain osmotically equivalent
internal concentrations by accumulating
high concentrations of potassium chloride.
36. “Salt-in” Strategy
Potassium ions enter the cell passively via
a uniporter. Sodium ions are pumped out.
Chloride enters the cell against the
membrane potential via cotransport with
sodium ions.
For every three molecules of potassium
chloride accumulated, two ATP are
hydrolyzed making this strategy more
energy efficient than the “compatible
solute” strategy.
37. “Salt-in” Strategy
To use this strategy all enzymes and
structural cell components must be
adapted to high salt concentrations to
ensure proper cell function.
38. Halobacterium: an extreme halophile
Halobacterium are members of domain
archaea.
Widely researched for their extreme
halophilism and unique structure.
Require salt concentrations between 15% to
saturation to live.
Use the “salt-in” strategy.
Produce ATP by respiration or by
bacteriorhodopsin.
39. Halobacterium
May also have halorhodopsin that pumps
chloride into the cell instead of pumping
protons out.
The Red Sea was named after
halobacterium that turns the water red
during massive blooms.
40. Facts
The term “red herring” comes from the
foul smell of salted meats that were
spoiled by halobacterium.
There have been considerable problems
with halophiles colonizing leather during
the salt curing process.
41. Applications
The extraction of carotene from carotene
rich halobacteria and halophilic algae that
can then be used as food additives or as
food-coloring agents.
The use of halophilic organisms in the
fermentation of soy sauce and Thai fish
sauce.
42. Applications
Other possible applications being explored:
Increasing crude oil extraction (MEOR)
Genetically engineering halophilic enzymes
encoding DNA into crops to allow for salt
tolerance
Treatment of waste water (petroleum)
43. Conclusions
Halophiles are salt tolerant organisms.
They are widespread and found in all three
domains.
The “salt-in” strategy uses less energy but
requires intracellular adaptations. Only a
few prokaryotes use it.
All other halophiles use the “compatible
solute” strategy that is energy expensive but
does not require special adaptations.
45. Summary
Now you know something about Extremophiles
Where they live & how they survive
They are interesting because
They have enzymes that work in unusual
conditions
The practical applications are interesting
Editor's Notes
Info on me, in NZ on volcanic hot springs and than here on subsurface GAB
***Any Questions, go ahead and ask **
1) You need to understand them before you can teach
2) A great deal of Info on web sites & new text books due to interest in astrobiology & who we are etc
3) These are fascinating creatures and I enjoyed putting presentation together
2) Review of enzymes, then extremozymes
Why is this the second talk??? A natural lead in to BioTech/Computing
3) - Interesting to scientists, and are interesting to us too.
- Life on other planets
- DNA fingerprinting, stonewashed jeans, and oil extraction
- Interdisciplinary lessons
Who lives in the temperature extremes?
Photosynthesis???
Can see that there is some overlap Thermophile/Acidophile and Halophile/Alkaliphile
White Sands???
Different from temperature
Halophiles - Osmosis
3) Because interior tends to be normal...
Wrapping up review of enzymes, they have limitations
Remember definition, a protein that catalyses chemical reactions without being changed
Remember last slide on enzymes, each of these situations destroy or inhibit an enzyme
2) leads to genetic prospecting, but first
Here is a wild application that caught my eye…
Enzyme needs to work in soapy (alkaline) solution