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; Sanjeevan, V N; Swapna, Antony P; Afsal, V V; Anil Kumar, P R(Elsevier, May 26, 2012)
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Abstract:
Anti-lipopolysaccharide factors are small proteins that bind and neutralize lipopolysaccharide and exhibit
potent antimicrobial activities. This study presents the molecular characterization and phylogenetic analysis
of the first ALF isoform (Pp-ALF1; JQ745295) identified from the hemocytes of Portunus pelagicus. The full
length cDNA of Pp-ALF1 consisted of 880 base pairs encoding 293 amino acids with an ORF of 123 amino
acids and contains a putative signal peptide of 24 amino acids. Pp-ALF1 possessed a predicted molecular
weight (MW) of 13.86 kDa and theoretical isoelectric point (pI) of 8.49. Two highly conserved cysteine residues
and putative LPS binding domain were observed in Pp-ALF1. Peptide model of Pp-ALF1 consisted of
two α-helices crowded against a four-strand β-sheet. Comparison of amino acid sequences and neighbor
joining tree showed that Pp-ALF1 has a maximum similarity (46%) to ALF present in Portunus trituberculatus
followed by 39% similarity to ALF of Eriocheir sinensis and 38% similarity to ALFs of Scylla paramamosain and
Scylla serrata. Pp-ALF1 is found to be a new isoform of ALF family and its characteristic similarity with other
known ALFs signifies its role in protection against invading pathogens.
Bright Singh, I S; Rosamma, Philip; Swapna, Antony P; Naveen, Sathyan; Anil Kumar, P R; Chaithanya, E R; Sajeevan, V N(Springer, November 25, 2012)
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Abstract:
Hepcidin is cysteine-rich short peptide of
innate immune system of fishes, equipped to perform prevention
and proliferation of invading pathogens like bacteria
and viruses by limiting iron availability and activating
intracellular cascades. Hepcidins are diverse in teleost
fishes, due to the varied aquatic environments including
exposure to pathogens, oxygenation and iron concentration.
In the present study, we report a 87-amino acid (aa)
preprohepcidin (Hepc-CB1) with a signal peptide of 24 aa,
a prodomain of 39 aa and a bioactive mature peptide of 24
aa from the gill mRNA transcripts of the deep-sea fish
spinyjaw greeneye, Chlorophthalmus bicornis. Molecular
characterisation and phylogenetic analysis categorised the
peptide to HAMP2-like group with a mature peptide of
2.53 kDa; a net positive charge (?3) and capacity to form
b-hairpin-like structure configured by 8 conserved cysteines.
The present work provides new insight into the mass
gene duplication events and adaptive evolution of hepcidin
isoforms with respect to environmental influences and
positive Darwinian selection. This work reports a novel
hepcidin isoform under the group HAMP2 from a nonacanthopterygian
deep-sea fish, C. bicornis
Description:
Probiotics & Antimicro. Prot. (2013) 5:1–7
DOI 10.1007/s12602-012-9120-0
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