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; Rosamma, Philip; Chaithanya, E R; Anil Kumar, P R; Sherine, Sonia Cubelio; Naveen, Sathyan(Springer, May 23, 2013)
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Abstract:
Hepcidin is a family of short cysteine-rich
antimicrobial peptides (AMPs) participating in various
physiological functions with inevitable role in host immune
responses. Present study deals with identification and
characterisation of a novel hepcidin isoform from coral fish
Zanclus cornutus. The 81 amino acid (aa) preprohepcidin
obtained from Z. cornutus consists of a hydrophobic aa rich
22 mer signal peptide, a highly variable proregion of 35 aa
and a bioactive mature peptide with 8 conserved cysteine
residues which contribute to the disulphide back bone. The
mature hepcidin, Zc-hepc1 has a theoretical isoelectric
point of 7.46, a predicted molecular weight of 2.43 kDa
and a net positive charge of ?1. Phylogenetic analysis
grouped Z. cornutus hepcidin with HAMP2 group hepcidins
confirming the divergent evolution of hepcidin-like
peptide in fishes. Zc-hepc1 can attain a b-hairpin-like
structure with two antiparallel b-sheets. This is the first
report of an AMP from the coral fish Z. cornutus.
Description:
Probiotics & Antimicro. Prot. (2013) 5:187–194
DOI 10.1007/s12602-013-9139-x
Bright Singh, I S; Rosamma, Philip; Swapna, Antony P(Elsevier, June 23, 2011)
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Abstract:
Antimicrobial peptides (AMPs) play a major role in innate immunity. Penaeidins are a family of AMPs that
appear to be expressed in all penaeid shrimps. Penaeidins are composed of an N-terminal proline-rich
domain, followed by a C-terminal domain containing six cysteine residues organized in two doublets. This
study reports the first penaeidin AMP sequence, Fi-penaeidin (GenBank accession number HM243617) from
the Indian white shrimp, Fenneropenaeus indicus. The full length cDNA consists of 186 base pairs encoding 61
amino acidswith an ORF of 42 amino acids and contains a putative signal peptide of 19 amino acids. Comparison
of F. indicus penaeidin (Fi-penaeidin) with other known penaeidins showed that it shared maximum similarity
with penaeidins of Farfantepenaeus paulensis and Farfantepenaeus subtilis (96% each). Fi-penaeidin has a predicted
molecular weight (MW) of 4.478 kDa and theoretical isoelectric point (pI) of 5.3
Bright Singh, I S; Rosamma, Philip; Chaithanya, E R; Swapna, Antony P; Afsal, V V(Elsevier, June 27, 2012)
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Abstract:
Anti-lipopolysaccharide factors (ALFs), a type of cationic antimicrobial peptides (AMPs), and their derivatives
are becoming predominant candidates for potential drugs in viral and bacterial diseases. This study
reports the first ALF from the mud crab Scylla tranquebarica (StALF, JQ899453) and the second ALF isoform
from the blue swimmer crab Portunus pelagicus (PpALF2, JQ899452). Both sequences encoded for precursor
molecules, starting with a signal peptide containing 26 amino acid residues, followed by a highly
cationic mature peptide, containing two conserved cysteine residues flanking a putative lipopolysaccharide
(LPS)-binding domain. BLAST analysis revealed that both PpALF2 and StALF exhibited significant
similarity with crustacean ALF sequences. The predicted molecular mass of the mature ALFs was 11.2 kDa
with an estimated pI of 10.0. PpALF2 and StALF also showed the typical pattern of alternating hydrophobic
and hydrophilic residues in their putative disulphide loop, suggesting that they comprise the same
functional domain. Phylogenetic analysis showed that PpALF2 and StALF have similar evolutionary status
and they were phylogenetically ancient immune effector molecules which may play an essential role in
the host defense mechanism. The spatial structures of PpALF2 and StALF possessed four beta-strands and
two alpha-helices. The results indicated that there were more than one ALF involved in crab immunity
against various pathogens. ALFs would provide candidate promising therapeutic or prophylactic agents
in health management and diseases control in crustacean aquaculture