A First Analysis of Metallome Biosignatures of Hyperthermophilic Archaea

[摘要] To date, no experimental data has been reported for the metallome of hyperthermophilic microorganisms although their metal requirements for growth are known to be unique. Here, experiments were conducted to determine (i) cellular trace metal concentrations of the hyperthermophilic ArchaeaMethanococcus jannaschiiandPyrococcus furiosus, and (ii) a first estimate of the metallome for these hyperthermophilic species via ICP-MS. The metal contents of these cells were compared to parallel experiments using the mesophilic bacteriumEscherichia coligrown under aerobic and anaerobic conditions. Fe and Zn were typically the most abundant metals in cells. Metal concentrations forE. coligrown aerobically decreased in the order Fe > Zn > Cu > Mo > Ni > W > Co.In contrast,M. jannaschiiandP. furiosusshow almost the reverse pattern with elevated Ni, Co, and W concentrations. Of the three organisms, a biosignature is potentially demonstrated for the methanogenM. jannaschiithat may, in part, be related to the metallome requirements of methanogenesis. The bioavailability of trace metals more than likely has varied through time. If hyperthermophiles are very ancient, then the trace metal patterns observed here may begin to provide some insights regarding Earth's earliest cells and in turn, early Earth chemistry.

[学科分类] 微生物学和免疫学