| 摘要 |
The present invention provides recombinant bacteria strains, such as Bacillus or Clostridium strains, lacking one or more genes commonly used for selecting recombinants (i.e., selection marker genes). More particularly, the present invention provides recombinant bacteria strains, containing one or more additional copies of its own gene or genes and/or one or more foreign genes artificially inserted in the host chromosomal DNA or extra-chromosomal DNA (e.g., a plasmid) without any selection marker gene or genes, such as an antibiotic resistance gene of any foreign origin. This allows for the introduction of the resultant recombinant Bacillus or Clostridium strain into the environment or into animals or humans without any contaminating selection marker gene. The recombinant strain, while lacking detrimental genes such as selection marker genes, may contain one or more desirable genes such as genes encoding insecticidal proteins or antigens for immunizing animals and humans. The present invention also provides methods for producing the recombinant bacterial strains. |
