Thermotoga is a genus of the phylum Thermotogota. Members of Thermotoga are hyperthermophilic bacteria whose cell is wrapped in a unique sheath-like outer membrane, called a "toga".
The members of the phylum stain Gram-negative as they possess a thin peptidoglycan in between two lipid bilayers, albeit both peculiar.[2] The peptidoglycan is unusual as the crosslink is not only meso-diaminopimelate as occurs in Pseudomonadota, but D-lysine.[NB 1][3]
The species are anaerobes with varying degrees of oxygen tolerance. They are capable of reducing elemental sulphur (S0) to hydrogen sulphide.[2]
Whether thermophily is an innovation of the lineage or an ancestral trait is unclear and cannot be determined.
The genome of Thermotoga maritima was sequenced in 1999, revealing several genes of archaeal origin, possibly allowing its thermophilic adaptation.[4] The CG (cytosine-guanine) content of T. maritima is 46.2%;[2] most thermophiles in fact have high CG content; this has led to the speculation that CG content may be a non-essential consequence to thermophily and not the driver towards thermophily.[5][6]
The paper and the chapter in Bergey's manual were authored by several authors including the microbiologists Karl Stetter and Carl Woese.[2]
The Neo-Latin feminine name "thermotoga" means "the hot outer garment", being a combination of the Greeknoun θέρμη (therme, heat)[7] or more correctly the adjective θερμός, ή, όν (thermos, e, on, hot)[8] and the Latin feminine noun toga (the Roman outer garment).[2]