Molecular Characterization and Gene Expression Profiling ... - CUSAT

Chapter 2
Tiger shrimp (P. monodon) is one of the most important cultivated
penaeid shrimps in the world. However, the shrimp aquaculture industry is
suffering from diseases linked to infection by viral pathogens, which cause a
drastic decrease in shrimp production, resulting in huge economic losses. To
overcome this problem, studies should be focused on developing strategies
of controlling viral diseases to ensure long-term survival of shrimp
aquaculture. The increased prevalence of disease outbreak is contributing to
the rising costs of aquaculture of shrimp and marine fishes. Furthermore,
bacterial resistance arising from over usage of conventional antibiotics
against infection by pathogens in aquaculture, agriculture, and human
medicine is becoming widespread, and has led to a corresponding increase
in the number of attempts to find effective replacements. AMPs are a largely
unexplored group of antimicrobial compounds that are gaining prominence
as potential therapeutic agents (Hancock and Patrzykat, 2002).
In the present study, seven AMP genes viz., ALF-1 ALF-2, crustin-1,
crustin-2, crustin-3, penaeidin-3 and penaeidin-5 were successfully isolated
from the haemocytes of P. monodon.
ALFs are small basic proteins of approximately 100 amino acids that
were initially characterized from the haemolymph of distantly related
arthropods, the horseshoe crabs T. tridentatus (Aketagawa et al., 1986) and L.
polyphemus (Muta et al., 1987). Thereafter, several ALF homologs have been
identified from P. monodon (Supungul et al., 2004) and many other shrimp
species including L. setiferus (Gross et al., 2001), F. chinensis (ALFFc) (Liu et
al., 2005), M. japonicas (M-ALF) (Nagoshi et al., 2006), P. leniusculus (Liu et al.,
2006), L. vannamei, L. styrirostris lobster and mud crab (Imjongjirak et al.,
2007). The growing number of relatively conserved ALF genes identified
with apparently conserved functions being characterized across taxa seems
to indicate the likely importance of ALF in shrimps besides the AMPs in the
penaeidin family (Gueguen et al., 2006).
Molecular Characterization and Gene Expression Profiling of Antimicrobial Peptides in Penaeid Shrimps
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