**5. Mode of action of protein Cry**

Currently the insect resistant transgenic plants expressing genes, inductors, an insectici‐ dal protein called Cry, derived from the bacterium *Bacillus thuringiensis*(Bt). The mecha‐ nisms by which proteins exert their effect are *Cry* elucidated by pore formation model discussed below:

The mode of action of Cry proteins, produced by the plant, it is accomplished, orally, by susceptible insect. The process begins by solubilization of crystals in alkaline pH around 9.5, in the gut of insects, releasing protoxin of 130 kDa to Cry1 and Cry2 to 79kDa.. After this breakdown, the protoxinare activated by digestive enzymes, forming toxic fragments of 60-65 kDa. These monomers bind to receptors specific primary, locat‐ ed in the apical membrane of the microvillus membranes of the columnar cells of the in‐ testine of the larva. It is in this step that the affinity between the toxin and the receiver, for example, Cry1ae protein, lepdopteros is recognized as an important factor in deter‐ mining the spectrum insecticidal Cry proteins. Later, the monomers bind to secondary receivers, which are proteins ancoradorasglicosil-phosphatidyl-inisitol (API), as phos‐ phates and alkaline, to the lepidoptero*Heliothisvirences*. After this binding, the now oligô‐ merose inserts into the membrane, where there are receptors for API, and leads to the formation of pores in the cell membrane of the intestinal epithelium and therefore de‐ struction of microvilli membranes, hypertrophy of epithelial cells, vacuolization of cyto‐ plasm, cell lyses and intestinal paralysis/death of the insect in [11, 41].
