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.
Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, Nevada 89119, USA.
Faegheh
F
Moazeni
Gaosen
G
Zhang
Henry J
HJ
Sun
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