We previously described the developing of a semisynthetic medium that allowed the developing of adult H. irritants in the laboratory. It was also described the finding of a B. thuringiensis strain (BtHf) with entomopathogenic activity against the larvae stage of the insect. Toxicity analysis indicated that the activity was present in the bacteria paraesporal crystal, which was composed of at least one protein of 130-140kD. Here we described the cloning, identification and heterologous expression in E. coli, of two Cry genes present in the BtHf strain. By using a set of primers complementary to genes encoding high MW Cry proteins, we were able to PCR amplify two genes from BtHf DNA. The nucleotide sequence of these genes reveled their identity as related to Cry 1 type. One of these genes was recently described and its insect specificity is at present unknown. Using the pET expression system, several attempts to express deleted versions of these genes in E. coli were unsuccessful however; the complete versions of both genes were successfully overexpressed. This will allow us to carry out experiments in order to verify that the toxic activity resides in the paraesporal crystal proteins of BtHf as well as to analyze the toxic potency of each protein.
