Sunday, March 10, 2013
How to Thrive in Battery Acid and Among Toxic Metals
In the movie Alien, the title character is an extraterrestrial creature that can survive brutal heat and resist the effects of toxins.
In real life, organisms with similar traits exist, such as the "extremophile" red alga Galdieria sulphuraria.
In hot springs in Yellowstone National Park, Galdieria uses energy from the sun to produce sugars through photosynthesis.
In the darkness of old mineshafts in drainage as caustic as battery acid, it feeds on bacteria and survives high concentrations of arsenic and heavy metals.
How has a one-celled alga acquired such flexibility and resilience?
To answer this question, an international research team led by Gerald Schoenknecht of Oklahoma State University and Andreas Weber and Martin Lercher of Heinrich-Heine-Universitat (Heinrich-Heine University) in Dusseldorf, Germany, decoded genetic information in Galdieria.
They are three of 18 co-authors of a paper on the findings published in this week's issue of the journal Science.
The scientists made an unexpected discovery: Galdieria's genome shows clear signs of borrowing genes from its neighbors.
Many genes that contribute to Galdieria's adaptations were not inherited from its ancestor red algae, but were acquired from bacteria or archaebacteria.
This "horizontal gene transfer" is typical for the evolution of bacteria, researchers say.
However, Galdieria is the first known organism with a nucleus (called a eukaryote) that has adapted to extreme environments based on horizontal gene transfer.