Diether and Tetraether Phospholipids and Glycolipids as Molecular Markers for Archaebacteria (Archaea)

摘要

Archaebacteria (Archaea) inhabit extreme environments globally: extreme halophiles in nearly saturated salty locales; methanogens in anoxic environments; and extreme thermophiles or thermoacidophiles at high temperatures or at both high temperatures and low pH. A new group of archaebacteria has recently been found to be highly concentrated and widely distributed in marine bacterioplankton. Archaea are clearly delineated from all other organisms by their unique ribosomal RNA (rRNA) sequences, cell wall structures and membrane lipids. The latter are derived from diphytanylglycerol diether (archaeol) and its dimer, dibiphytanyldiglycerol tetraether (caldarchaeol), as lipid cores (hydrophobic moieties) instead of from diacylglycerol diesters. Archaeal phospholipids, glycolipids and archaeol or caldarchaeol lipid cores should be useful molecular markers as aids for identification of archaeal subgroups andin some cases of individual genera, and for determination of their biomass in mixed microbial communities. These molecular markers should be useful as an adjunct to rRna Sequencing for detecting and characterizing new archaeal genera in the environment, such as those recently discovered in oceanic bacterioplankton.