Moult-inhibiting fusion protein augments while polyclonal antisera attenuate moult stages and duration in Penaeus monodon

- Innovative means of moult regulation in P. monodon with fusion MIH I and antisera developed.
- Mf-PmMIH I significantly augments moult cycle duration in D2 and D3 stage of P. monodon.
- Anti-mf-PmMIH I significantly attenuates moulting, showing tendency to shift from C to D0 - stage.

Moulting in crustaceans is regulated by moult-inhibiting hormone (MIH) of the CHH family neuropeptides. The inhibitory functions of MIH have pivotal roles in growth and reproduction of Penaeus monodon. In this study, we report the expression of a thioredoxin-fused mature MIH I protein (mf-PmMIH I) of P. monodon in a bacterial system and its use as antigen to raise polyclonal antiserum (anti-mf-PmMIH I). 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. The translation expression vector construct (mf-PmMIH I+pET32a+) upon induction produced 29.85 kDa mature MIH I fusion protein (mf-PmMIH I). The purified fusion protein was used as exogenous MIH I and as antigen to raise polyclonal antisera. When fusion protein (mf-PmMIH I) was injected into D2 and D3 stages of juvenile shrimp, the moult cycle duration was extended significantly to 16.67 ± 1.03 and 14.67 ± 1.03 days respectively compared to that of 11.67 ± 1.03 days in controls. Moult duration was further reduced to 8.33 ± 0.82 days when polyclonal antiserum (anti-mf-PmMIH I - 1:500 dilutions) was injected. Anti-mf-PmMIH I immunolocalized MIH I producing neurosecretory cells in the eyestalk of P. monodon. In short, the present manuscript reports an innovative means of moult regulation in P. monodon with thioredoxin fused MIH I and antisera developed.