OCCURRENCE OF 3 DIFFERENT BINDING-SITES FOR BACILLUS-THURINGIENSIS DELTA-ENDOTOXINS IN THE MIDGUT BRUSH-BORDER MEMBRANE OF THE POTATO-TUBERMOTH, PHTHORIMAEA-OPERCULELLA (ZELLER)
B. Escriche et al., OCCURRENCE OF 3 DIFFERENT BINDING-SITES FOR BACILLUS-THURINGIENSIS DELTA-ENDOTOXINS IN THE MIDGUT BRUSH-BORDER MEMBRANE OF THE POTATO-TUBERMOTH, PHTHORIMAEA-OPERCULELLA (ZELLER), Archives of insect biochemistry and physiology, 26(4), 1994, pp. 315-327
The potato tuber moth is susceptible to at least three insecticidal cr
ystal proteins (ICPs) from Bacillus thuringiensis: CrylA(b), CrylB, an
d CrylC. To design useful combinations of toxin genes either in transg
enic plants or in new genetically modified B. thuringiensis strains, i
t is necessary to determine the binding characteristics of the differe
nt ICPs so as not to combine a pair sharing the same binding site. Thi
s has been accomplished using two different techniques: I-125-labeling
of the ICPs with further measurement of the radioactivity bound to br
ush border membrane vesicles, and microscopic visualization of the bou
nd ICPs by enzyme-linked reagents such as antibodies or streptavidin u
sing biotinylated ICPs. Our results st-cow that CrylA(b), CrylB, and C
rylC bind to different sites in the brush border membrane of midgut ep
ithelial cells. Also, the affinity of the binding sites for the ICPs a
nd their concentration in brush border membrane vesicles has been dete
rmined in a laboratory strain and a storage collected population. No s
ignificant differences were found between these two strains. (C) 1994
Wiley-iiss, Inc.