Interplay between transcriptional regulators and VapBC toxin-antitoxin loci during thermal stress response in extremely thermoacidophilic archaea.

Thermoacidophilic archaea lack sigma factors and the large inventory of heat shock proteins (HSPs) widespread in bacterial genomes, suggesting other strategies for handling thermal stress are involved. Heat shock transcriptomes for the thermoacidophilic archaeon Saccharolobus (f. Sulfolobus) solfataricus 98/2 revealed genes that were highly responsive to thermal stress, including transcriptional regulators YtrA (Ssol_2420) and FadR (Ssol_0314), as well as type II toxin-antitoxin (TA) loci VapBC6 (Ssol_2337, Ssol_2338) and VapBC22 (Ssol_0819, Ssol_0818).

A mutant ('lab strain') of the hyperthermophilic archaeon Pyrococcus furiosus, lacking flagella, has unusual growth physiology.

A mutant ('lab strain') of the hyperthermophilic archaeon Pyrococcus furiosus DSM3638 exhibited an extended exponential phase and atypical cell aggregation behavior. Genomic DNA from the mutant culture was sequenced and compared to wild-type (WT) DSM3638, revealing 145 genes with one or more insertions, deletions, or substitutions (12 silent, 33 amino acid substitutions, and 100 frame shifts). Approximately, half of the mutated genes were transposases or hypothetical proteins.

The genus Thermotoga: recent developments.

The genus Thermotoga comprises extremely thermophilic (Topt > or = 70 degrees C) and hyperthermophilic (Topt > or = 80 degrees C) bacteria, which have been extensively studied for insights into the basis for life at elevated temperatures and for biotechnological opportunities (e.g. biohydrogen production, biocatalysis).