title: Molecular characterization, transcriptional profiling, and antibacterial potential of G-type lysozyme from seahorse (Hippocampus abdominalis).
abstract: Lysozymes are a family of enzymes that catalyze the hydrolysis of bacterial cell wall, acting as antimicrobial effectors of the innate immune system. In the present study, an ortholog of goose-type lysozyme (ShLysG) from the big-belly seahorse (Hippocampus abdominalis) was identified and characterized structurally and functionally. The full-length cDNA sequence (1213 bp) of ShLysG is comprised of an open reading frame made up of 552 bp, encoding a polypeptide of 184 amino acid (aa) with a predicted molecular mass of 20 kDa. In silico analysis of ShLysG revealed the absence of signal peptide and the presence of a characteristic bacterial soluble lytic transglycosylase (SLT) domain bearing three catalytic residues (Glu71, Asp84, and Asp95) and seven N-acetyl-d-glucosamine binding sites (Glu71, Asp95, Tyr98, His99, Ile117, Tyr145, and Asn146). Homology analysis demonstrated that the aa sequence of ShLysG shared 60.7-67.4% identity and 72.6-79.3% similarity with the orthologs of other teleosts. Phylogenetic analysis of ShLysG indicated a closest relationship with the ortholog from Gadus morhua. In healthy seahorse, ShLysG mRNA showed a constitutive expression in all the tissues examined, with the highest expression in kidney and the least expression in liver. The ShLysG mRNA levels were also shown significant elevation upon the bacterial and pathogen-associated molecular pattern (PAMPs) challenges. Furthermore, lytic activities of ShLysG recombinant protein were detected against several Gram-negative and Gram-positive bacterial species. Taken together, these results suggest that ShLysG might possess a potential immune defensive role against invading microbial pathogens in seahorse.
authors.affiliation: Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Jeju International Marine Science Research & Education Center, Korea Institute of Ocean Science & Technology (KIOST), Jeju Special Self-Governing Province, 63349, Republic of Korea.
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Ko
authors.affiliation: Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea. Electronic address: oneqiang@msn.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
authors.forename: S D N K
authors.initials: SDNK
authors.lastname: Bathige
authors.affiliation: Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D020609:Edwardsiella tarda / Q000502:physiology; D004756:Enterobacteriaceae Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D005393:Fish Diseases / Q000235:genetics* / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D009113:Muramidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000494:pharmacology*; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D023701:Smegmamorpha; D013290:Streptococcal Infections / Q000235:genetics / Q000382:microbiology / Q000662:veterinary*; D000070058:Streptococcus iniae / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D008070:Lipopolysaccharides; D000069452:Pathogen-Associated Molecular Pattern Molecules; D012333:RNA, Messenger; D011994:Recombinant Proteins; D009113:Muramidase; D011070:Poly I-C
keywords: Antibacterial activity; Big-belly seahorse; Immune defense; Lysozyme; Tissue specific mRNA expression