Papers in the Biological Sciences


Date of this Version



Journal of Bacteriology, Jan. 2001, p. 287–291 Vol. 183, No. 1


Copyright © 2001, American Society for Microbiology. All Rights Reserved.


Few antibiotics targeting members of the archaeal domain are currently available for genetic studies. Since

bacterial antibiotics are frequently directed against competing and related organisms, archaea by analogy

might produce effective antiarchaeal antibiotics. Peptide antibiotic (halocin) preparations from euryarchaeal

halophilic strains S8a, GN101, and TuA4 were found to be toxic for members of the hyperthermophilic

crenarchaeal genus Sulfolobus. No toxicity was evident against representative bacteria or eukarya. Halocin S8

(strain S8a) and halocin R1 (strain GN101) preparations were cytostatic, while halocin A4 (strain TuA4)

preparations were cytocidal. Subsequent studies focused on the use of halocin A4 preparations and Sulfolobus

solfataricus. Strain TuA4 cell lysates were not toxic for S. solfataricus, and protease (but not nuclease) treatment

of the halocin A4 preparation inactivated toxicity, indicating that the A4 toxic factor must be a secreted protein.

Potassium chloride supplementation of the Sulfolobus assay medium potentiated toxicity, implicating use of a

salt-dependent mechanism. The utility of halocin A4 preparations for genetic manipulation of S. solfataricus

was assessed through the isolation of UV-induced resistant mutants. The mutants exhibited stable phenotypes

and were placed into distinct classes based on their levels of resistance.

Included in

Biology Commons