title: Intravital imaging of Bacillus thuringiensis Cry1A toxin binding sites in the midgut of silkworm.
abstract: Identification of the resistance mechanism of insects against Bacillus thuringiensis Cry1A toxin is becoming an increasingly challenging task. This fact highlights the need for establishing new methods to further explore the molecular interactions of Cry1A toxin with insects and the receptor-binding region of Cry1A toxins for their wider application as biopesticides and a gene source for gene-modified crops. In this contribution, a quantum dot-based near-infrared fluorescence imaging method has been applied for direct dynamic tracking of the specific binding of Cry1A toxins, CrylAa and CrylAc, to the midgut tissue of silkworm. The in vitro fluorescence imaging displayed the higher binding specificity of CrylAa-QD probes compared to CrylAc-QD to the brush border membrane vesicles of midgut from silkworm. The in vivo imaging demonstrated that more CrylAa-QDs binding to silkworm midgut could be effectively and distinctly monitored in living silkworms. Furthermore, frozen section analysis clearly indicated the broader receptor-binding region of Cry1Aa compared to that of Cry1Ac in the midgut part. These observations suggest that the insecticidal activity of Cry toxins may depend on the receptor-binding sites, and this scatheless and visual near-infrared fluorescence imaging could provide a new avenue to study the resistance mechanism to maintain the insecticidal activity of B. thuringiensis toxins.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; College of Food Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; College of Food Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; College of Food Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China. Electronic address: hyhan@mail.hzau.edu.cn.
authors.forename: Heyou
authors.initials: H
authors.lastname: Han
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Xuepu
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D001665:Binding Sites; D012831:Bombyx / Q000166:cytology / Q000378:metabolism*; D004731:Endotoxins / Q000378:metabolism* / Q000633:toxicity; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D007413:Intestinal Mucosa / Q000378:metabolism*; D061848:Optical Imaging / Q000379:methods*; D045663:Quantum Dots
chemical_list: D004731:Endotoxins; D005022:Ethyldimethylaminopropyl Carbodiimide
keywords: Binding sites; Cry1A toxins; In vivo imaging; Quantum dots