Title
The Effects of Enterolobium contortisiliquum Serine Protease Inhibitor on the Survival of the Termite Nasutitermes corniger, and its Use as Affinity Adsorbent to Purify Termite Proteases
Author
Rodrigo da Silva Ferreira, Thiago Henrique Napoleão, Rosemeire A. Silva‐Lucca, Mariana Cristina Cabral Silva, Patrícia Maria Guedes Paiva, Maria Luiza Vilela Oliva
Year
2018
Journal
Pest Management Science
Abstract
Termites are one of the main wood destroying insects. Nasutitermes corniger (Isoptera: Termitidae), can invade and attack urban wooden environments used in the structures of buildings. The use of synthetic pesticides is the traditional method used to prevent termite attack; however, these compounds generally cause harm to the environment.This paper describes the insecticidal activity of Enterolobium contortisiliquum protease inhibitor (EcTI) on Nasutitermes corniger workers and soldiers. EcTI induced mortality in Nasutitermes corniger workers (LC50 0.242 mg mL‐1 at 6 days of exposure). Gut extracts from workers and soldiers showed protease activity on the H‐D‐Pro‐Phe‐Arg‐pNan substrate. EcTI inhibited gut proteases in N. corniger at nM concentrations in vitro. The inhibitory activity towards termite enzymes was stable within the range of 25 to 65 °C. The inhibitor’s unordered structure showed a high content of β‐sheets; its secondary structure and the thermal denaturation monitored by CD showed a two‐state transition and melting temperature (Tm) of approximately 73 °C. Our results contribute to the understanding of Nasutitermes corniger complexity and provide new clues to achieve a better comprehension of the molecular mechanism of action of insecticides to this pest.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Thermal stability, Protein folding, Thermodynamics, Biochemistry