Insecticidal Effects of Hemocoelic Delivery of Cry Toxins in Larvae.

Insecticidal effects of Cry toxins in hemocoel of larvae have not been properly evaluated. In the present study, hemocoelic injection of four representative Cry toxins i.e.

Cloning and characterization of a riboflavin-binding hexamerin from the larval fat body of a lepidopteran stored grain pest, Corcyra cephalonica.

In the present study, a riboflavin-binding hexamerin (RbHex) was cloned and characterized from the larval fat body of Corcyra cephalonica. The complete cDNA (2121bp) encodes a 706-amino acid protein with a molecular mass ~82kDa. Expression of RbHex 82 was predominant in fat body among larval tissues.

Functional interpretation of a non-gut hemocoelic tissue aminopeptidase N (APN) in a lepidopteran insect pest Achaea janata.

Insect midgut membrane-anchored aminopeptidases N (APNs) are Zn(++) dependent metalloproteases. Their primary role in dietary protein digestion and also as receptors in Cry toxin-induced pathogenesis is well documented. APN expression in few non-gut hemocoelic tissues of lepidopteran insects has also been reported but their functions are widely unknown.

Characterization and regulation of Bacillus thuringiensis Cry toxin binding aminopeptidases N (APNs) from non-gut visceral tissues, Malpighian tubule and salivary gland: Comparison with midgut-specific APN in the moth Achaea janata.

Bacillus thuringiensis (Bt) crystal proteins (Cry) bind to aminopeptidase N (APN) receptors on insect midgut membrane leading to pore formation and subsequent death. However, evolution of insect resistance to Bt toxins threatens their long-term application. Therefore, search for new targets which could function as Cry toxin receptors is an immediate mandate.

Is hexamerin receptor a GPI-anchored protein in Achaea janata (Lepidoptera: Noctuidae)?

The process of uptake of hexamerins during metamorphosis from insect haemolymph by fat body cells is reminiscent of receptor-mediated endocytosis. Previously, we had identified a hexamerin-binding protein (HBP) and reported for the first time that uptake of hexamerins is dependent on the phosphorylation of HBP partly by a tyrosine kinase, which is, in turn, activated by 20-hydroxyecdysone (20E). However, the exact nature of HBP and the mechanism of interaction are still unknown.