Bright Singh, I S; Rosamma, Philip; Swapna, Antony P; Valsamma, Joseph(Elsevier, June 21, 2011)
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Abstract:
White Spot Syndrome Virus (WSSV) is the most devastating disease affecting shrimp culture around the
world. Though, considerable progress has been made in the detection and molecular characterization of WSSV
in recent years, information pertaining to immune gene expression in shrimps with respect to WSSV infection
remains limited. In this context, the present study was undertaken to understand the differential expression
of antimicrobial peptide (AMP) genes in the haemocytes of Penaeus monodon in response to WSSV infection
on a time-course basis employing semi-quantitative RT-PCR. The present work analyzes the expression profile
of six AMP genes (ALF, crustin-1, crustin-2, crustin-3, penaeidin-3 and penaeidin-5), eight WSSV genes (DNA
polymerase, endonuclease, immediate early gene, latency related gene, protein kinase, ribonucleotide
reductase, thymidine kinase and VP28) and three control genes (18S rRNA, β-actin and ELF) in P. monodon in
response to WSSV challenge. Penaeidins were found to be up-regulated during early hours of infection and
crustin-3 during late period of infection. However, ALF was found to be up-regulated early to late period of
WSSV infection. The present study suggests that AMPs viz. ALF and crustin-3 play an important role in
antiviral defense in shrimps. WSSV gene transcripts were detected post-challenge day 1 itself and increased
considerably day 5 onwards. Evaluation of the control genes confirmed ELF as the most reliable control gene
followed by 18S rRNA and β-actin for gene expression studies in shrimps. This study indicated the role of
AMPs in the protection of shrimps against viral infection and their possible control through the up-regulation
of AMPs
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