Parasporal crystal

It appears from our studies and reports in the literature that the parasporal crystal of BTI has gut-toxicity when fed to the mosquito ( ), both in vitro and im vivo cytotoxicity (3,22-24) and ni vivo neurotoxicity. Injected toxicity occurred in a number of insect species. The crude alkaline-dissolved... 

Cell diameter (lim) Sporangium swollen Motility Parasporal crystals Catalase Growth in 7% NaCl Capsule... 

Strains isolated from commercial products (supposed to containing Bacillus thuringiensis and used as organic pesticides by farmers) in the Laboratory of Bacteriology (Toulouse, France), and identified on the basis of parasporal crystal ceU inlusions presenceisolates from commercial preparations of biopesticides... 

The 6-endotoxin of B. . israelensis (H-14) is not as clearly understood as that of BTk. The parasporal crystal of BTi contains several proteins with molecular weights ranging from 26,000 to over 100,000d (9). Several authors have reported that the 26,000d protein has insecticidal activity (j , 11, 12). However, other reports suggest that the toxin is 66,000d, (13, 1 ). Because BTi has hemolytic and cytolytic activities in addition to insecticidal activities (15) the possibility exists that multiple toxin proteins exist in the crystal. However, evidence from genetics... 

Parasporal crystal are formed during sporulation. Manganese cation is essential for sporulation. Antisera prepared against endospores cross react with vegetative cells. 

Diphtheria toxin, a protein secreted by lysogenic strains of Corynebacterlum dlphtherlae, has been shown to be an effective inhibitor of the growth of Ehrlich carcinoma, both ascitic and solid, in mice. The effect is thou to be mediated primarily through inhibition of protein synthesis. Similarly, the parasporal crystal ( S -endotoxin) of B. thuringiansis has been reported to exertj tent anti-Yoshlda ascites carcinoma activity, with a hi therapeutic index . 

In 1953 Hannay 12) discovered that B. thuringiensis produced a diamond-shaped parasporal body in each cell at time of sporulation. He pointed out that this crystal was alkali-soluble and suggested that it might be connected with the pathogenicity of B. thuringiensis. 

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