Lipids of the ultra-thin square halophilic archaeonHaloquadratum walsbyi

[摘要] The lipid composition of the extremely halophilic archaeonHaloquadratum walsbyiwas investigated by thin-layer chromatography and electrospray ionization-mass spectrometry. The analysis of neutral lipids showed the presence of vitamin MK-8, squalene, carotene, bacterioruberin and several retinal isomers. The major polar lipids were phosphatidylglycerophosphate methyl ester, phosphatidylglycerosulfate, phosphatidylglycerol and sulfated diglycosyl diether lipid. Among cardiolipins, the tetra-phytanyl or dimeric phospholipids, only traces of bisphosphatidylglycerol were detected. When the cells were exposed to hypotonic medium, no changes in the membrane lipid composition occurred. Distinguishing it from other extreme halophiles of the Halobacteriaceae family, the osmotic stress did not induce the neo-synthesis of cardiolipins inH.walsbyi. The difference may depend on the three-laminar structure of the cell wall, which differs significantly from that of other Haloarchaea.

[学科分类] 微生物学和免疫学