Extremophiles

1
Extremophiles

• Extreme Halophiles are Models for Astrobiology
• Article by Shiladitya DasSarma

2
Introduction

• This article specifically focuses on halophiles,
  and how they are candidates to be able to survive
  on other planets, like mars for instance.
• Life on earth needs water but halophiles are one
  of the few that can withstand high concentrations
  of salts, which results from the evaporation of
  water.

3
Halophiles

• Live in high saline environments.
• They can control the amount of salt inside by
  osmotic pressure and chemical substances.
• They are found in brine salt, or any other areas
  with high salt concentrations.

4
Mars

• Mars has polar ice caps at both south and north
  poles
• There is also evidence of erosion, large floods
  and river systems which would suggest that water
  was once present .
• Mars has an atmosphere that contains nitrogen,
  carbon dioxide, argon, and oxygen.

5
Research

• The Great Salt Lake and the Dead Sea are the best
  environments to study halophiles and how they can
  survive in these salty environments.
• Regions of Antarctica, which have permanently
  cold high salt concentration, can have
  halophiles.
• Environments that have high saline are also found
  in the earths subsurface, in deep-sea basins.

6
Methods

• Genome sequencing can offer detailed information
  on varies halophiles, Proteomes can also offer
  detailed information.
• The Halobacterium species is a very good
  halophile to study and is useful for post-genomic
  studies, because it can respond to a series of
  different tests.
• Testing the growth rate of different organisms in
  different concentrations of NaCl can also be
  useful for knowing the tolerance level of an
  organism.

7
Results and Discussion

• This graph shows the growth rate of an
  organism versus NaCl concentration.

8
(No Transcript)
9
Acidic Proteomes

• Figure A shows the protein acidity among
  halophiles and other nonhalophiles.
• Halophiles have low isoelectric points or (pI).

10
Surface Charges

• Proteins from halophiles typically display high
  negative surface charges.
• This is because the acidic proteins dissolve
  readily in an environment with high salinity and
  reduced water.

11
DNA Microarray

• This figure shows gene expression changes in
  Halobacterium sp. NRC-1 under aerobic versus
  anaerobic growth.

12
DNA Microarray

• In this figure it shows gene expressions for
  dmsR versus ?dmsR strains.

13
Photosynthetic membrane

• This graph shows the absorption versus wavelength
  of chlorophyll-based photosynthetic membrane and
  retinal-based purple membrane.

14
Conclusion

• Since Halophiles are tolerate to so many forms of
  environmental stress they are excellent
  candidates for the term exophiles.
• The European Space Agency has already launched
  one halophile in space.

15
Resources

• http//www.nineplanets.org/mars.html
• http//library.thinkquest.org/CR0212089/halo.htm
• Microbe Magazine/Volume 1, Number 3, 2006,
  Shiladitya DasSarma.
• http//en.wikipedia.org/wiki/DNA_microarray
• http//en.wikipedia.org/wiki/Proteome