Isoprenoid quinones in an aerobic hyperthermophilic archaeon, Aeropyrum pernix

Aeropyrum pernix is the first strictly aerobic hyperthermophile known to gr ow heterotrophically at neutral pH and at temperatures up to 100 degrees C. Using a simple and sensitive frit-fast atom bombardment liquid chromatogra phy/mass spectrometry quinone analysis method, we analyzed the quinones in A. pel nix. This organism contained demethylmenaquinone analogs (DMK-6(H-n) ) and methionaquinone analogs (MTK-6(H-n)) when it was grown under vigorous shaking in the presence of air. The quinones were partially or fully satur ated with six isoprenyl units. Although DMK and MTK are the quinones found in eubacteria, this is the first report to demonstrate the simultaneous occ urrence of DMK and MTK in archaea. The effect of Na2S2O3 on the quinone com position was studied at concentrations of 0, 0.1 and 0.5% under aerobic gro wth conditions with shaking. The total quinone content was highest (83.4 mu g g(-1) dry cell weight) at 0.1% Na2S2O3 In the absence of Na2S2O3, only D MK-6 analogs were detected. While DMK analogs such as DMK-6(H-12), DMK-6(H- 10) and DMK-6(Hs) were the major quinones at 0.1% Na2S2O3, MTK analogs such as MTK-6(H-12) and MTK-6(H-10) were also detected. When the Na2S2O3 concen tration was increased to 0.5%, both DMK-6(Hs) and MTK-6(H-10) disappeared, while MTK-6(H-12) increased to approximately 20% of the total quinone conte nt. When A. pernix was grown under oxygen limitation in a tightly closed bo ttle without gas phase, MK-6(H-10) appeared. (C) 1999 Federation of Europea n Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.