JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Poster

B (Biogeosciences) » B-AO Astrobiology & the Origin of Life

[B-AO01] [EE] Astrobiology: Origins, Evolution, Distribution of Life

Wed. May 24, 2017 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL7)

[BAO01-P12] The diversity and structure determination of saturated and unsaturated archaeol derivatives characteristic for the halophilic archaea lipid-core

*Noriaki YAMAUCHI1 (1.Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University)

Keywords:archaea, isoprenoidal dither, structure determination, halophilic, halite

Archaea has a characteristic lipid-core, archaeol. Further, a characteristic diether lipid-core (C20-C25 diether (1)) which is constructed from one C25 and one C20 isoprenoid is produced by halophilic archaea. The C25 (long) hydrocarbon is linked with the C-2 of the glycerol[1]. Recently, Dawson et al. showed the existence of several unsaturated isoprenoid diethers (such as tentative structure 2) in the lipid-core of several halophilic archaea which was incubated with very high salt concentration[2].
Then, 1 and 2 were chemically synthesized according to the reported method[3] and the results were presented at the last year’s this meeting[4]. The analysis of the mass fragmentation of the TMS derivative, the structure of microbiological sample derived from halophilc archaea was confirmed as 1. Further, 2 is different from those of Dawson’s unsaturated diether.
About the diversities of these unsymmetrical diether, 1) The isomer of the C25 (long) hydrocarbon is linked with the C-3 of the glycerol 3 was synthesized and mass fragmentation of the TMS ether of 1 and 3 were observed. Teixidor’s report[5] of archaeol derivative from halite were decided to the mixture of 1 and 3 with almost equal amounts. It is suggested that the existence of the unrevealed halophilic archaea which can biosynthesize regioisomeric C25-C20 diether in halite and/or the ancient hypersaline environment. 2) The “real” structure of Dawson’s unsaturated archaeol derivative were assumed to the structure 4 or 5 from the intermediate of biosynthesis of tetraether lipid in thermophilic archaea[6]. Then, the chemical synthesis and mass fragmentation analysis of 4 and 5 will be presented.

[1] De Rosa et al., J. Gen. Microbiol., 128, 343 (1982).
[2] Dawson et al. Org. Geochem., 48, 1 (2012).
[3] Yamauchi Res. Org. Geochem., 29, 71 (2013).
[4] Yamauchi (2016) JpGU meeting 2016 BA001-P05.
[5] Texidor et al. (1993) Geochim. Cosmochim. Acta. 57, 4479.
[6] Nemoto et al. (2003) Extremophiles, 7, 235.