Table 1 Strains & vectors used in this study

T. neapolitana DSM 4359

Isolated from African continental solfataric springs

[27]

T. maritima MSB8

Isolated from geothermally heated sea floors in Italy and the Azores

[28]

T. sp. strain RQ7

Isolated from geothermally heated sea floors in Ribeira Quente, the Azores

[28]

Caldicellulosiruptor saccharolyticus DSM 8903

Isolated from a thermal pool of Taupo, New Zealand

[29]

E. coli DH5α

F^-endA1 hsdR17 (r_k^-, m_k⁺) supE44 thi-1 λ^-recA1 gyrA96 relA1 deoR Δ(lacZYA-argF)- U169 ϕ80dlacZΔM15

[30]

Plasmids

pKT1

pUC-derived plasmid, containing a kan cassette for thermostable kanamycin selections

[31]

pRQ7

Cryptic miniplasmid from T. sp. strain RQ7

[24]; GenBank: KF798180

pDH10

pRQ7 cloned between the EcoRI and XbaI sites of pKT1; Ap^r; Kan^r

[3]; GenBank: JN813374

pDH12

pRQ7 along with its duplicated fragment of 209 bp were cloned between the EcoRI and XbaI sites of pKT1; Ap^r, Kan^r

This study; GenBank: KF798179