<p style="text-align: justify;">The cotton line 3006-210-23 was developed to resist attack by lepidopteran insects pests and has demonstrated resistance to tobacco budworm (<i>Heliothis virescens</i>), pink bollworm (<i>Pectinophora gossypiella</i>), cotton bollworm (<i>Helicoverpa zea</i>), beet armyworm (<i>Spodoptera exigua</i>), and soybean looper (<i>Pseudoplusia includens</i>). This line produces, within its tissues, a synthetic version of the insecticidal protein Cry1Ac, a delta-endotoxin, originally derived from <i>Bacillus thuringiensis</i> var. <i>kurstaki</i>. Cry proteins act by binding to specific sites located in the brush border midgut epithelium of susceptible insect species. Following binding, cation-specific pores are formed that disrupt ion flow in the midgut, thereby causing paralysis and death. Cry1Ac is insecticidal only to lepidopteran insects and the specificity of action is directly attributable to the presence of specific binding sites in these insects. The epithelium of mammalian intestinal cells do not possess binding sites for delta-endotoxins of <i>B. thuringiensis</i>, therefore, humans and livestock animals are not susceptible to the damaging effects of these proteins.</p>
