Abstract.
Bacillus subtilis harboring the cat-86 constitutive plasmid pPL708C2 with an ochre mutation at the 9th codon (terc 9) was sensitive to chloramphenicol (Cms) and exhibited relative thermostability when heated at 47°C. Reversion to chloramphenicol resistance (Cmr) occurred at a frequency of 5.4 × 10−8. All of the plasmid Cmr revertants tested were thermosensitive. Similarly, wild-type pPL708C2 present in B. subtilis also rendered the bacterium thermosensitive. When a nonsense mutation is introduced at codon 141, however, this terc 141 variant of pPL708C2 failed to thermosensitize B. subtilis. Another variant of pPL708C2 that produces intact yet catalytically inactive CAT-86 has both His-16 and His-17 at the active site replaced by Pro. Nevertheless, cells of B. subtilis carrying this variant were thermosensitive. Plasmid-free and pPL708C2-bearing strains did not exhibit differences in major heat shock proteins. Electron micrographs revealed a threefold increase of inclusion bodies present in a strain harboring pPL708C2 when compared with those in an isogenic plasmid-free strain.
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Received: 26 July 1999 / Accepted: 30 August 1999
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Friedman, S., Chatakondu, S., Urbanski, D. et al. Overexpression of the cat-86 Gene Is Associated with Thermosensitivity in Bacillus subtilis . Curr Microbiol 40, 119–122 (2000). https://doi.org/10.1007/s002849910023
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DOI: https://doi.org/10.1007/s002849910023