Lecture # 18
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Today: Extremophiles!
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Turn your take-home short essays
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Reading For Friday: Chpt 6.5
http://www.change.org/petitions/usps-honor-new-horizons-and-the-exploration-of-pluto-with-a-usps-stamp
Your Research Papers
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Great Topics!
Most were broad – good to start broad, but you
will need to narrow these for your paper
Most need more peer reviewed articles
Revise your proposals
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Revised Proposals Due Monday March 19
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½ – 1 page + references
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Narrow your topic
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Reference at least 3 peer reviewed journal
articles
Use in-text referencing
When citing sources use a standard format that
includes authors, paper title, journal, year
Cells Getting Energy
H2 + 1/2 O2  H2O
1) Redox Reactions Release Energy
2) That Energy is Used To Create a Proton Gradient
3) Energy from the proton gradient is used to make ATP =
Usable energy for life!
This is a bit bizarre!
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Peter Mitchell
(Nobel Prize
1978)
Paul Boyer &
John Walker
(Nobel Prize
1997)
Why would life
use proton
gradients?
Methanogenisis
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Used by Chemoautotroph
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Process produces ½ an ATP of energy
Alkali Sea
Vents
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Naturally Create
Proton
Gradients!
Perhaps the first
life harnessed
these gradients
Extremophiles!
What is an Extremophile?
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Loves Extreme Environment
(As opposed to mesophiles)
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What is an extreme environment? Our own
biased definition?
Does it mean organisms that require extreme
environments or ones that simply tolerate
them?
What are
extremophiles?
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Many Archea
(though not all)
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Some Bacteria
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Some Eukarya
A few very cool Extremophiles
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Acidophile – growth at pH of 3 or below
Alkaphile – growth at pH of 9 or above
Anaerobe – does not need Oxygen (some can tolerate it, others die)
Cryptoendolith – dudes that live in fissures in rocks
Halophile – requires at least 0.2M of salt
Hyperthermophile – thrives at 80-122C
Hypolith – lives under rocks in cold desserts
Lithoautotroph – sole source of carbon is CO2
Osmophile – likes high sugar concentrations
Piezophile – likes high hydrostatic pressure
Cryophile – temps below -15C
Radioresistant – can take LOTS of ionizing radiation (UV typically)
Thermophile – Temps 60-80 C
Thermoacidophile – 70-80C and pH 2-3
Xerophile – Very dry (atacama dessert)
Tardigrades (“water bears”)
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Hibernation mode (tun state)
nearly indestructible
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Survive temperatures
from -253°C to 151°C
Exposure to x-rays, and
vacuum conditions
Perfluorocarbon fluid at a
pressure of 600 MPa,
(that's almost 6,000 times
atmospheric pressure at
sea level)
Always new discoveries
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Pitch Lake, in Trinidad.
Natural deposit of Asphalt (which was once
exported for roads in NYC).
107 cells/gram
Geobacter
sulfurreducens
Microbial fuel cells
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These could really pay off when connected to
wastewater treatment plants.
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He says the process could
potentially be used
anywhere, but could provide
both clean water and power
to communities in
developing countries.
"The main application right
now is in waste water
treatment where you could
effectively treat the water,
but also gain some extra
energy from waste heat.
"Instead of having a net
drain, we have a net gain."
Environmental
parameter
type
Definition
temperature
hyperthermophile
thermophile
mesophile
psychrophile
growth >80°C
growth 60-80°C
15-60°C
<15°C
radiation
pressure
, 113°C
Synechococcus lividis
Homo sapiens
Psychrobacter, some
insects
Pyrolobus fumarii
Deinococcus
radiodurans
barophile
piezophile
vacuum
desiccation
examples
xerophiles
Weight loving
Pressure loving
unknown
For microbe, 130 MPa
tolerates vacuum (space
devoid of matter)
tardigrades, insects,
microbes, seeds.
Anhydrobiotic
Artemia salina
; nematodes,
microbes, fungi,
lichens
Environmental
parameter
type
Definition
examples
salinity
halophile
Salt loving
Halobacteriacea, Dunaliella salina
pH
alkaliphile
pH >9
Natronobacterium, Bacillus firmus
acidophile
low pH loving
OF4, Spirulina spp. (all pH
10.5)
Cyanidium caldarium, Ferroplasma
sp. (both pH 0)
oxygen tension anaerobe
microaerophil
aerobe
cannot tolerate O2
tolerates some O2
requires O2
Methanococcus
jannaschii
Clostridium
Homo sapiens
chemical
extremes
Can tolerate high
concentrations of metal
(metalotolerant)
gases
metals
Cyanidium caldarium
(pure
CO2)
s(Cu,
As, Cd, Zn); Ralstonia sp.
CH34 (Zn, Co, Cd, Hg,
Pb)
Ferroplasma acidarmanu