Abstract
Sau 3A1 partial digestion fragments from B. thuringiensis var. kurstaki HD-1 plasmid DNA were ligated into the BamHI site of the cloning vector pBR322 and transformed into E. coli strain HB101. Colonies presumed to contain recombinant plasmids were screened for production of an antigen that would react with antibody made against B. thuringiensis crystals. One strain, ES12, was isolated by using this procedure. ES12 contains a plasmid of MW 11 .times. 106 that has DNA sequence homology with pBR322 and with MW 30 .times. 106 and MW 47 .times. 106 plasmids of B. thuringiensis. It makes a protein antigen, detected by antibodies to crystal, which has the same electrophoretic mobility as the B. thuringiensis crystal protein. Protein extracts of ES12 are toxic to larvae of the tobacco hornworm Manduca sexta.