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Afsal V.V.,Microbiology and Biochemistry | Antony S.P.,Microbiology and Biochemistry | Chaithanya E.R.,Microbiology and Biochemistry | Bright Singh I.S.,National Center for Aquatic Animal Health | Philip R.,Microbiology and Biochemistry
Molecular Immunology | Year: 2012

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. © 2012 Elsevier Ltd.


Afsal V.V.,Microbiology and Biochemistry | Antony S.P.,Microbiology and Biochemistry | Sanjeevan V.N.,Center for Marine Living Resources and Ecology | Anil Kumar P.R.,Microbiology and Biochemistry | And 2 more authors.
Aquaculture | Year: 2012

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. © 2012 Elsevier B.V.


Antony S.P.,Microbiology and Biochemistry | Singh I.S.B.,National Center for Aquatic Animal Health | Philip R.,Microbiology and Biochemistry
Aquaculture | Year: 2011

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 acids with 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. © 2011 Elsevier B.V.


Chaithanya E.R.,Cochin University of Science and Technology | Philip R.,Cochin University of Science and Technology | Sathyan N.,Cochin University of Science and Technology | Anil Kumar P.R.,Cochin University of Science and Technology | And 4 more authors.
Probiotics and Antimicrobial Proteins | Year: 2013

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 β-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 non-acanthopterygian deep-sea fish, C. bicornis. © 2012 Springer Science+Business Media New York.


Antony S.P.,Cochin University of Science and Technology | Singh I.S.B.,National Center for Aquatic Animal Health | Sudheer N.S.,National Center for Aquatic Animal Health | Vrinda S.,National Center for Aquatic Animal Health | And 2 more authors.
Immunobiology | Year: 2011

A crustin-like 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 crustin-like AMP from other shrimp crustins. The differential expression of the crustin-like 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 β-glucan isolates (extracted from C. haemulonii S27 and C. sake S165) were noted during the study. Responses to the application of two gram-positive probiotic bacteria (Bacillus MCCB101 and Micrococcus MCCB104) were also observed. The immune profile was recorded pre- and post-challenge white spot syndrome virus (WSSV) by semi-quantitative RT-PCR. Expressions of seven WSSV genes were also observed for studying the intensity of viral infection in the experimental animals. The crustin-like AMP was found to be constitutively expressed in the animal and a significant down-regulation could be noted post-challenge WSSV. Remarkable down-regulation of the gene was observed in the immunostimulant fed animals pre-challenge followed by a significant up-regulation post-challenge WSSV. Tissue-wise expression of crustin-like 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 crustin-like AMP and confer significant protection to P. monodon against WSSV infection. © 2010 Elsevier GmbH.

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