Biochemical analysis of silk proteins of the mango leaf webber, Orthaga exvinacea Hampson (Lepidoptera: Pyralidae)

Abstract

The mango leaf webber, Orthaga exvinacea makes silken webs and galleries during its larval stage. Silk is produced from the silk gland of this insect. Quantitative and qualitative analysis of proteins from the silk glands of last three larval stages and pre-pupae were conducted. Significant differences were observed among different stages. SDS-PAGE of proteins from anterior, middle and posterior regions of silk glands of final instar larvae revealed that the posterior region had several proteins than the other two regions of silk glands. Anterior region had no visible protein bands. The proteins of molecular weights 269 kDa, 251 kDa, 175 kDa, 125 kDa and 66 kDa were common to posterior region of silk glands, web and cocoon of the mango leaf webber. The regenerated protein obtained from the web had a molecular weight of 125 kDa, which may be a fibroin like web and cocoon except 125 kDa molecular weight protein may be sericins, which are the members of a glue protein family. The regenerated liquid silk had two UV absorption peaks at 214 nm and 272 nm. The anti-UV properties of silk protein of Orthaga exvinacea can be exploited in cosmetic industry.