Molecular Characterization and Gene Expression Profiling ... - CUSAT

Chapter 2
inhibit the endotoxin or lipopolysaccharide (LPS) mediated coagulation
system, and thus exhibits strong anti-bacterial activity against the gram-
negative bacteria in particular (Morita et al., 1985). It binds to LPS and
neutralizes LPS-induced gelation of limulus amebocyte lysate (Alpert et al.,
1992). Limulus ALF has been proved to possess strong antibacterial activity,
especially on the growth of gram-negative bacteria (Wang et al., 2002). As
most of the infectious bacterial pathogens in shrimp are gram-negative
bacteria, studies on ALF will be more useful in shrimp disease control.
Although the anti-gram-positive bacterial activity of ALFs has been
reported, its binding to the gram-positive bacteria has not been studied in
depth (Somboonwiwat et al., 2005). With strong and broad spectrum
antimicrobial activity, the ALFs and their derivatives are becoming potential
therapeutic agents for prophylactic treatment of viral and bacterial infectious
diseases, as well as for septic shocks (Vallespi et al., 2000; Pan et al., 2007).
ALFPm3, the most abundantly expressed isoform of P. monodon, was
cloned and expressed in a recombinant system and its antimicrobial activity
was investigated (Somboonwiwat et al., 2005). ALFPm3 has a potent and
broad spectrum of activity against several classes of microorganisms,
including gram-positive bacteria, gram-negative bacteria and filamentous
fungi (Somboonwiwat et al., 2005). Moreover, ALFPm3 has also an antiviral
effect against human herpes virus (HSV-1) (Carriel-Gomes et al., 2007). The
ALFPm3 has been expressed in the yeast Pichia pastoris expression system
(Somboonwiwat et al., 2005) and the recombinant ALFPm3 protein exhibited
antimicrobial activity against gram-negative and gram-positive bacteria and
fungi. Another possible role of the ALF as an antiviral molecule has been
shown in P. leniusculus as it interferes with the replication of white spot
syndrome virus (Liu et al., 2006).
More recently, the ALF was identified and characterized in many
crustaceans including Fenneropenaeus chinensis; ALFFc (Liu et al., 2005),
Marsupenaeus japonicus; M-ALF (Nagoshi et al., 2006), Penaeus monodon;
Molecular Characterization and Gene Expression Profiling of Antimicrobial Peptides in Penaeid Shrimps
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