You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
28 August 2008What do membrane lipids tell us about the microorganisms living in extreme environments?
To search for extraterrestrial life surrogate extreme environments on Earth have been chosen for
investigation. An example of a surrogate site is the Canadian subpermafrost. Investigations into microbial
communities occurred by access fracture borehole water in the Lupin gold mine, and drill rock cores and
drilling waters in the High Lake region of Nunavut, Canada. Membrane lipid analyses uses GC/MS and
HPLC/ES/MS/MS to provide estimates of biomass, phospholipid (PLFA) and respiratory quinone
composition, and compositional changes related to membrane stress caused by nutritional limitations or
exposure to toxic conditions. Lupin fracture borehole waters were collected from 800 to 1200 meters,
while the High Lake rock cores were collected from 335 to 535 meters. Biomass estimates based on PLFA
ranged from 0.25 to 22 pmol L-1 for the Lupin waters. High Lake drill waters had biomass that ranged
from below detection limits (bdl) to 595 pmol/ml, while rock core samples had biomass estimates ranging
from bdl to 32 pmol g-1. PLFA profiles revealed the presence of both Gram +/- bacteria and sulfatereducing
bacteria. Specific PLFA ratios indicate that the bacterial communities were physiologically
stressed. Menaquinones were the most abundant but varied in the dominant isoprene units between the two
sites. Ubiquinone to menaquinone ratio indicated that these samples have been anoxic for a long time.
Methods to detect life signatures at surrogate sites on Earth will be critical for assessing extraterrestrial life.
Currently, the membrane lipid analyses provide additional information not easily provided by other
The alert did not successfully save. Please try again later.
Susan M. Pfiffner, Sarah DiFurio, Ying-Dong Gan, Richard B. Hoover, "What do membrane lipids tell us about the microorganisms living in extreme environments?," Proc. SPIE 7097, Instruments, Methods, and Missions for Astrobiology XI, 70970M (28 August 2008);