Biomolecular changes that occur in the antennal gland of the giant freshwater prawn (Machrobrachium rosenbergii)

In decapod crustaceans, the antennal gland (AnG) is a major primary source of externally secreted biomolecules, and some may act as pheromones that play a major role in aquatic animal communication. In aquatic crustaceans, sex pheromones regulate reproductive behaviours, yet they remain largely unidentified besides the N-acetylglucosamine-1,5-lactone (NAGL) that stimulates male to female attraction. In this study, we used an AnG transcriptome of the female giant freshwater prawn (Macrobrachium rosenbergii) to predict the secretion of 226 proteins, including the most abundantly expressed transcripts encoding the Spaetzle protein, a serine protease inhibitor, and an arthropodial cuticle protein AMP 8.1. A quantitative proteome analysis of the female AnG at intermolt, premolt and postmolt, identified numerous proteins of different abundances, such as the hemocyanin subunit 1 that is most abundant at intermolt. We also show that hemocyanin subunit 1 is present within water surrounding females. Of those metabolites identified, we demonstrate that the NAGL and N-acetylglucosamine (NAG) can bind with high affinity to hemocyanin subunit 1. In summary, this study has revealed components of the female giant freshwater prawn AnG that are released and contribute to further research towards understanding crustacean conspecific signalling.