title: Molecular characterization and antibacterial activity of a phage-type lysozyme from the Manila clam, Ruditapes philippinarum.
abstract: A phage-type lysozyme, designed as RpPLYZ, was cloned and characterized from the clam Ruditapes philippinarum. The full-length cDNA of RpPLYZ was of 699 bp with an open reading frame (ORF) of 534 bp, encoding a polypeptide of 177-amino acid with a calculated molecular mass of 19.6 kDa and an isoelectric point of 9.05. Multiple alignments and phylogenetic analysis strongly suggested that RpPLYZ was a new member of the phage-type lysozyme family. The mRNA transcript of RpPLYZ was found to be constitutively expressed in a wide range of tissues and mainly in hemocytes and mantle. The relative expression of RpPLYZ mRNA in hemocytes was significantly up-regulated at 6, 24, 48 and 72 h after Vibrio anguillarum challenge. The recombinant RpPLYZ (rRpPLYZ) showed high activity against Entherobacter cloacae and Staphyloccocus aureus, and less effective towards Entherobacter aerogenes and V. anguillarum. Moreover, the optimal pH, temperature and ionic strength for rRpPLYZ activity was determined to be 5.5, 50 °C and 5 mM, respectively. These results suggested that RpPLYZ was a member of the phage-type lysozyme family and perhaps played an important role in the immune responses against bacterial invasion.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Dinglong
authors.initials: D
authors.lastname: Yang
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Lizhu
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China; Muping Coastal Environment Research Station, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Ruiwen
authors.initials: R
authors.lastname: Cao
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Chenglong
authors.initials: C
authors.lastname: Ji
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Cong
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China; Muping Coastal Environment Research Station, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China. Electronic address: jmzhao@yic.ac.cn.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D049872:Bivalvia / Q000145:classification / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004754:Enterobacter / Q000187:drug effects / Q000502:physiology; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009994:Osmolar Concentration; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology; D013696:Temperature; D014733:Vibrio / Q000187:drug effects / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D018076:DNA, Complementary; D012333:RNA, Messenger; D009113:Muramidase
keywords: Antimicrobial activity; Phage-type lysozyme; Ruditapes philippinarum; Tissue distribution