Bright Singh, I S; Swapna, Antony P; Sudheer, N S; Vrinda, S; Priyaja, P; Rosamma, Philip(Elsevier, May 20, 2010)
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Abstract:
A crustinlike
antimicrobial peptide from the haemocytes of giant tiger shrimp, Penaeus monodon was
partially characterized at the molecular level and phylogenetic analysis was performed. The partial coding
sequence of 299 bp and 91 deduced amino acid residues possessed conserved cysteine residues characteristic
of the shrimp crustins. Phylogenetic tree and sequence comparison clearly confirmed divergence
of this crustinlike
AMP from other shrimp crustins. The differential expression of the crustinlike
AMP
in P. monodon in response to the administration of various immunostimulants viz., two marine yeasts
(Candida haemulonii S27 and Candida sake S165) and two bglucan
isolates (extracted from C. haemulonii
S27 and C. sake S165) were noted during the study. Responses to the application of two grampositive
probiotic bacteria (Bacillus MCCB101 and Micrococcus MCCB104) were also observed. The immune profile
was recorded preand
postchallenge
white spot syndrome virus (WSSV) by semiquantitative
RTPCR.
Expressions of seven WSSV genes were also observed for studying the intensity of viral infection in
the experimental animals. The crustinlike
AMP was found to be constitutively expressed in the animal
and a significant downregulation
could be noted postchallenge
WSSV. Remarkable downregulation
of the gene was observed in the immunostimulant fed animals prechallenge
followed by a significant
upregulation
postchallenge
WSSV. Tissuewise
expression of crustinlike
AMP on administration of C.
haemulonii and Bacillus showed maximum transcripts in gill and intestine. The marine yeast, C. haemulonii
and the probiotic bacteria, Bacillus were found to enhance the production of crustinlike
AMP and
confer significant protection to P. monodon against WSSV infection