Abstract: The cytA gene encoding the 28 kDa polypeptide of Bacillus thuringiensis israelensis crystals was disrupted in the 72 MDa resident plasmid by in vivo recombination. The absence of the 28 kDa protein in B. thuringiensis israelensis did not affect the crystallization of the other toxic components of the parasporal body. However, the absence of the 28 kDa protein did abolish the hemolytic activity of B. thuringiensis serovar israelensis crystals. The mosquitocidal activity of the 28 kDa protein-free crystals did not differ significantly from the wild-type crystals.

Abstract: The invention relates to a vector for transforming microorganisms capable of undergoing sporulation and which contains itself a heterologous insert comprising a DNA sequence coding for at least part of crystal protein, particularly that of B. thuringensis. It also concerns the polypeptides expressed by said microorganisms and having insecticidal properties similar to those of crystal protein, the microorganisms themselves, as transformed by this vector and insecticidal composition including either said polypeptide or the microorganism itself.

Abstract: The cytA gene encoding the 28 kDa polypeptide of Bacillus thuringiensis israelensis crystals was disrupted in the 72 MDa resident plasmid by in vivo recombination. The absence of the 28 kDa protein in B. thuringiensis israelensis did not affect the crystallization of the other toxic components of the parasporal body. However, the absence of the 28 kDa protein did abolish the hemolytic activity of B. thuringiensis serovar israelensis crystals. The mosquitocidal activity of the 28 kDa protein-free crystals did not differ significantly from the wild-type crystals.

Abstract: The cyta gene encoding the 28 kDa polypeptide of Bacillus thuringiensis israelensis crystals was disrupted in the 72 MDa resident plasmid by in vivo recombination. The absence of the 28 kDa protein in B. thuringiensis israelensis did not affect the crystallization of the other toxic components of the parasporal body. However, the absence of the 28 kDa protein did abolish the hemolytic activity of B. thuringiensis serovar israelensis crystals. The mosquitocidal activity of the 28 kDa protein-free crystals did not differ significantly from the wild-type crystals.

Abstract: The invention relates to any fragment of DNA derived from the genome of B. licheniformis coding for a polypeptide of 46 amino acids, or for any fragment of this polypeptide possessing the property of stimulating the production of enzymes secreted by B. subtilis by introduction of the above-mentioned fragment of DNA into this latter by the intermediary of a plasmid.The invention also relates to a procedure for the stimulation of the production of a specific polypeptide by B. subtilis by introduction of the above-mentioned fragment of DNA in a strain of B. subtilis, the genome of which has been modified so that it contains a sequence of DNA coding for the said specific polypeptide.