Cell Structure Changes in the Hyperthermophilic Crenarchaeon Sulfolobus islandicus Lacking the S-Layer.Rediscovery of the ancient evolutionary relationship between archaea and eukaryotes has revitalized interest in archaeal cell biology.  Here, we investigate the architecture and cellular roles of the S-layer in the hyperthermophilic crenarchaeon Sulfolobus islandicus Electron micrographs of mutant cells lacking slaA or both slaA and slaB confirm the absence of the outermost layer (SlaA), whereas cells with intact or partially or completely detached SlaA are observed for the ΔslaB mutant. 
THERM