Biogenesis of the Crystalline Inclusion of Bacillus thuringiensis during Sporulation

Abstract

The biogenesis of the crystalline inclusion of Bacillus thuringiensis has been studied in the more general context of sporulation and in regard to the formation of some spore constituents.It has been shown that crystal protein is essentially formed during stages TI1 and IV, before the acquisition of octanol resistance. One fraction of protein spore coats which is solubilized by a reducing agent associated with urea or guanidine hydrochloride, is synthesised a t the same time ; a more insoluble cystine-rich fraction is formed later, during stage V, just before the heat resistance is reached.The analysis of bacterial extracts a t intervals during sporogenesis indicates preferential synthesis of insoluble proteins (or proteins bound to membraneous structures), crystal protein represents a large proportion of these proteins. Immunological characterisation of crystal protein, with autoradiographic experiments reveals a t least three antigens produced simultaneously after t, and continuously throughout the biogenesis.The sporulation of a mutant non crystal bearing strain was studied; it has been shown that this mutant accumulates soluble proteins having some of the properties of crystal constituents ; in this case the synthesis and maturation of spore coats arise earlier in the course of sporulation than in the wild strain.All results suggest a relation between crystal protein and a protein fraction of the spore coats.

Cloning and expression of the Bacillus thuringiensis crystal protein gene in Escherichia coli.

“…The intracellular protein crystals produced by sporulating cells of Bacillus thuringiensis account for 20-30% of the dry weight of sporulated cultures (1)(2)(3). The crystals are composed of repeating subunits of a Mr 130,000 polypeptide (4,5) which is thought also to be a major component ofthe spore coat ofcrystalproducing strains (6,7).…”

“…When the large plasmid fraction was used as a source of inserts, one colony was found that reacted specifically with antibodies to the 1 Fig. 1) (39).…”

Efficacy of Bacillus thuringiensis Cry14 toxin against root knot nematode, Meloidogyne javanica

“…After 72 h, one fraction of bacterial suspension was centrifuged at 8500 g for 15 min, the culture supernatants were collected. The spore crystal mixtures were prepared according to Lecadet and Dedonder (1971).…”

An Insect Toxin from Spores of Bacillus thuringiensis and Bacillus cereus

“…Considerable evidence has accumulated (see above, and Lecadet & Dedonder, 1971 ;Ribier, 1971;Lecadet, Chevrier & Dedonder, 1972;Ribier & Lecadet, 1973;Herbert & Gould, 1973) indicating a relationship between the protein of the crystal of B. thuringiensis and spore material which is solubilized under conditions similar to those necessary to dissolve crystals. However, the toxicity of spore extracts has not previously been reported although whole spores are known to be toxic.…”