Application of the Scorpion Neurotoxin AaIT against Insect Pests

Androctonus australis Hector insect toxin (AaIT), an insect-selective toxin, was identified in the venom of the scorpion Androctonus australis. The exclusive and specific target of the toxin is the voltage-gated sodium channels of the insect, resulting in fast excitatory paralysis and even death. Because of its strict toxic selectivity and high bioactivity, AaIT has been widely used in experiments exploring pest bio-control. Recombinant expression of AaIT in a baculovirus or a fungus can increase their virulence to insect pests and diseases vectors. Likewise, transgenic plants expressing AaIT have notable anti-insect activity. AaIT is an efficient toxin and has great potential to be used in the development of commercial insecticides.

Biochemical and electrophoretic analyses of saliva from the predatory reduviid species Rhynocoris marginatus (Fab.).

The saliva of Rhynocoris marginatus consists of amylase, invertase, trehalase, protease, acid phosphatase, alkaline phosphatase, phospholipase, lipase, trypsin, hyaluronidase, and esterase. All enzyme activities were significantly higher in the saliva of female R. marginatus when compared to the saliva of male individuals. The saliva was analyzed by tricine SDS/PAGE, sephadex column chromatography, FT-IR, and MALDI-TOF. The pH of the saliva was slightly alkali. The SDS/PAGE revealed a few proteins with molecular masses greater than 29.5 and 36.2 kDa for male and female predator saliva respectively. The FT-IR spectrum confirmed the acidic, proteinaceous, enzymatic, and aromatic nature of the saliva. The MALDI-TOF-MS revealed the presence of enzymes, proteins, peptides, and other biomolecules. The most prominent peptides were named as RmIT-1 (3.79 kDa), RmIT-2 (9.7 kDa), and RmIT-3 (10.94 kDa) (Rhynocoris marginatus Insect Toxin). Further studies are underway to isolate and identify these biomolecules.