Vrinda Sukumaran
Cochin University of Science and Technology, India
Title: Thioredoxin fused molt-inhibiting hormone and polyclonal antisera: Effect on molt duration in Penaeus monodon
Biography
Biography: Vrinda Sukumaran
Abstract
The inhibitory functions of Moult Inhibiting Hormone (MIH) have a pivotal role in growth and reproduction of Penaeus monodon. In this study we report the production of biologically active thioredoxin-fused mature MIH I protein (mf-PmMIH I) of P. monodon for the first time in a bacterial system and its use as an antigen to raise polyclonal anti-sera (anti-mf-PmMIH I). Using reverse transcription, the open reading frame (ORF) of 357 bp cDNA sequence of MIH I was isolated from the eyestalk of P. monodon cultured in the Indian brackish water rearing culture system. The mature MIH I gene of 231 bp that codes for 77 amino acids was cloned into the Escherichia coli thioredoxin gene fusion expression system. Upon induction 29.85 kDa mature MIH I fusion protein (mf-PmMIH I) was expressed, purified and refolded for use as exogenous MIH I and as an antigen to raise polyclonal antisera. The specificity and sensitivity of the raised polyclonal antisera against the mf-PmMIH I antigen was examined by Western blot, ELISA and immunofluorescence. The thioredoxin-fused mature MIH I protein and the polyclonal antisera developed were tested in adult P. monodon (n=20, 10-15 g) to determine their acute biological effects on augmentation and attenuation of molt cycle duration. In the shrimps injected with mf-PmMIH I, the molt cycle duration was significantly increased to 16.67±1.03 days while the anti-mf-PmMIH I exhibited a molt duration that was significantly reduced to 8.33±0.82 days. This innovative MIHI fusion protein appears to be practical in terms of effective molting.