Conjugative Transfer, Stability and Expression of a Plasmid Encoding a cry1Ac Gene in Bacillus Cereus Group Strains

FEMS Microbiol Lett. 2004 Feb 9;231(1):45-52. doi: 10.1016/S0378-1097(03)00925-X.


The plasmid pHT73 containing cry1Ac and tagged with an erythromycin resistance gene was transferred from Bacillus thuringiensis subspecies kurstaki KT0 to several Bacillus cereus group strains by conjugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and phase contrast microscopy showed that the transconjugants containing plasmid pHT73 could express Cry1Ac toxin and produce bipyramidal crystalline inclusion bodies during sporulation. The study demonstrated that pHT73 could be transferred to B. thuringiensis subsp. kurstaki, several B. cereus strains and Bacillus mycoides. Under non-selective conditions, the stability of the pHT73 plasmid in the transconjugants was found to be 58.2-100% after 100 generations and 4-96% after 200 generations. The variations are mainly caused by the choice of receptor strain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus cereus / genetics*
  • Bacillus cereus / metabolism
  • Bacillus thuringiensis / genetics*
  • Bacillus thuringiensis / metabolism
  • Bacterial Proteins
  • Conjugation, Genetic*
  • Electrophoresis, Agar Gel
  • Gene Expression
  • Insect Proteins / genetics
  • Insect Proteins / metabolism*
  • Plasmids / genetics*
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*


  • Bacterial Proteins
  • Cry toxin receptors
  • Insect Proteins
  • Receptors, Cell Surface