Murae Tatsushi, Takamatsu Yuichiro, Muraoka Ryohei, Endoh Satoshi, Yamauchi Noriaki
Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki, Fukuoka 812-8581, Japan.
J Mass Spectrom. 2002 Feb;37(2):209-15. doi: 10.1002/jms.276.
Calditocaldarchaeol (neutral tetraether lipid) from Sulfolobus acidocaldarius (acidothermophilic archaea) and intact total lipid from the thermoacidophilic archaea Sulfolobus sp. was examined by electrospray ionization time-of-flight mass spectrometry in the negative-ion mode using high resolution. When the sample was injected as a solution in a 3:1 mixture of methanol (MeOH) and chloroform (CHCl(3)) using an infusion system, the total ether lipid afforded molecular-related ions as M - H for acidic polar lipids containing a phosphoric or sulfuric group, and as M + Cl ion for neutral glycolipids. The attachment of chloride was confirmed by the observation of M + Br ion, instead of M + Cl ion, when a 3:1 mixture of MeOH and CHBr(3) was used in place of MeOH-CHCl(3) as the solvent. The composition of tetraether neutral glycolipids that are different from each other only in the number of five-membered rings in the isoprenoid chain was determined on the basis of the isotope-resolved mass spectrum of M + Cl ions. As for acidic tetraether lipids, molecular-related ions M - H) were not observed when the 3:1 MeOH-CHBr(3) mixture was used as the solvent. These results together afforded a facile method of distinguishing neutral from acidic tetraether lipids in intact total lipids of acidothermophilic archaea. This method was applied to determine the difference of the number of five-membered rings in isoprenyl chains of neutral tetraether glycolipids yielded by the Sulfolobus sp. grown at different temperatures. Discrimination of neutral tetraether glycolipids from acidic tetraether lipids in the total lipids obtained from Thermoplasma sp. was also achieved by this method.
采用高分辨率负离子模式，通过电喷雾电离飞行时间质谱对嗜酸热硫化叶菌（嗜热嗜酸古菌）的卡尔迪嗜热四醚脂（中性四醚脂质）以及嗜热嗜酸古菌硫化叶菌属的完整总脂质进行了检测。当使用输注系统将样品以甲醇（MeOH）和氯仿（CHCl₃）3:1混合物中的溶液形式注入时，对于含有磷酸或硫酸基团的酸性极性脂质，总醚脂质产生与分子相关的离子[M - H]⁻，对于中性糖脂则产生[M + Cl]⁻离子。当使用MeOH和CHBr₃的3:1混合物代替MeOH-CHCl₃作为溶剂时，通过观察[M + Br]⁻离子而非[M + Cl]⁻离子，证实了氯离子的附着。基于[M + Cl]⁻离子的同位素分辨质谱，确定了仅在类异戊二烯链中五元环数量上彼此不同的四醚中性糖脂的组成。对于酸性四醚脂质，当使用3:1的MeOH-CHBr₃混合物作为溶剂时，未观察到与分子相关的离子[M - H]⁻。这些结果共同提供了一种在嗜热嗜酸古菌完整总脂质中区分中性和酸性四醚脂质的简便方法。该方法用于确定在不同温度下生长的硫化叶菌属产生的中性四醚糖脂类异戊二烯链中五元环数量的差异。通过该方法也实现了对嗜热栖热菌属总脂质中中性四醚糖脂与酸性四醚脂质的区分。
