AMP gene synthesis [15]. Mas gene mediates hemocyte adhesion,
bacterial binding, and antimicrobial activity in proPO system [44].
The up-regulation level of Mas gene was lower in multipleinfection
group than that in virus, bacteria or PS singly injected
groups. In accordance, Mas gene was previously cloned in
P. monodon, and its transcript expression levels were found to be
upregulated upon bacterial challenge with V. harveyi [45]. In vivo
further study revealed that Mas gene exhibited the opsonic activity
as shown by a more rapid clearance and removal from the hemolymph
of V. harveyi coated the recombinant proteins than uncoated
control bacteria [44]. In penaeid shrimp, the rapid clearance of