Thermosipho globiformans sp. nov., an anaerobic thermophilic bacterium that transforms into multicellular spheroids with a defect in peptidoglycan formation.

An anaerobic rod-shaped thermophile was isolated from a hydrothermal vent at Suiyo Seamount, Izu-Bonin Arc, western Pacific Ocean, and was named strain MN14(T). The rods were gram-negative-staining, non-motile without flagella, 2-4 µm long and 0.5 µm wide, and divided by binary fission in the mid-exponential phase.

Effect of growth temperature and growth phase on the lipid composition of the archaeal membrane from Thermococcus kodakaraensis.

Archaea have unique membrane lipids typified by ether linkages of the glycerol-to-isoprenoid chains with sn-2,3 stereochemistry that runs against the naturally occurring sn-1,2 stereochemistry of the glycerophospholipids of Bacteria and Eukarya. Membrane lipids were extracted and analyzed from the hyperthermophilic archaeon, Thermococcus kodakaraensis, cultivated at various temperatures. At all growth temperatures examined, both the diphytanylglycerol diether (archaeol, C(20)) and diphytanyldiglycerol tetraether (caldarchaeol, C(40)) were identified as saturated forms, and no other lipids could be identified.

Thermococcus coalescens sp. nov., a cell-fusing hyperthermophilic archaeon from Suiyo Seamount.

A cell-fusing hyperthermophilic archaeon was isolated from hydrothermal fluid obtained from Suiyo Seamount of the Izu-Bonin Arc. The isolate, TS1(T), is an irregular coccus, usually 0.5-2 microm in diameter and motile with a polar tuft of flagella.