Molecular characterization and antibacterial activity of a phage-type lysozyme from the Manila clam, Ruditapes philippinarum

Dinglong Yang; Qing Wang; Lizhu Chen; Yongliang Liu; Ruiwen Cao; Huifeng Wu; Fei Li; Chenglong Ji; Ming Cong; Jianmin Zhao

doi:10.1016/j.fsi.2017.03.051

Molecular characterization and antibacterial activity of a phage-type lysozyme from the Manila clam, Ruditapes philippinarum

Fish Shellfish Immunol. 2017 Jun:65:17-24. doi: 10.1016/j.fsi.2017.03.051. Epub 2017 Mar 30.

Authors

Dinglong Yang¹, Qing Wang², Lizhu Chen¹, Yongliang Liu³, Ruiwen Cao¹, Huifeng Wu², Fei Li², Chenglong Ji², Ming Cong², Jianmin Zhao⁴

Affiliations

¹ 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.
² Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, PR China.
³ 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.
⁴ 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.

PMID: 28365385
DOI: 10.1016/j.fsi.2017.03.051

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.

Keywords: Antimicrobial activity; Phage-type lysozyme; Ruditapes philippinarum; Tissue distribution.

MeSH terms

Amino Acid Sequence
Animals
Anti-Bacterial Agents / pharmacology
Base Sequence
Bivalvia / classification
Bivalvia / genetics*
Bivalvia / immunology*
Bivalvia / microbiology
DNA, Complementary / genetics
DNA, Complementary / metabolism
Enterobacter / drug effects
Enterobacter / physiology
Gene Expression*
Hydrogen-Ion Concentration
Muramidase / chemistry
Muramidase / genetics*
Muramidase / metabolism*
Osmolar Concentration
Phylogeny
RNA, Messenger / genetics
RNA, Messenger / metabolism
Sequence Alignment / veterinary
Staphylococcus aureus / drug effects
Staphylococcus aureus / physiology
Temperature
Vibrio / drug effects
Vibrio / physiology

Substances

Anti-Bacterial Agents
DNA, Complementary
RNA, Messenger
Muramidase