Imperfect asymmetry of life: earth microbial communities prefer D-lactate but can use L-lactate also.
Asymmetrical utilization of chiral compounds has been sought on Mars as evidence for biological activity. This method was recently validated in glucose. Earth organisms utilize D-glucose, not L-glucose, a perfect asymmetry. In this study, we tested the method in lactate and found utilization of both enantiomers. Soil-, sediment-, and lake-borne microbial communities prefer D-lactate but can consume L-lactate if given extra time to acclimate. This situation is termed imperfect asymmetry. Future life-detection mission investigators need to be aware of imperfect asymmetry so as not to miss relatively subtle signs of life.
Moazeni
Faegheh
F
Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, Nevada 89119, USA.
Zhang
Gaosen
G
Sun
Henry J
HJ
D001105:Archaea / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D018534:Earth, Planet; D005618:Fresh Water / Q000382:microbiology; D019015:Geologic Sediments / Q000382:microbiology; D007536:Isomerism; D019344:Lactic Acid / Q000737:chemistry* / Q000378:metabolism*; D012988:Soil Microbiology
D019344:Lactic Acid