Identification and characterization of a novel goose-type and chicken-type lysozyme genes in Chinese rare minnow (Gobiocypris rarus) with potent antimicrobial activity
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Lysozymes act as important innate immunity molecule against various pathogen infections. In the present study, a new c-type and g-type lysozymes were isolated from rare minnow Gobiocypris rarus. The deduced amino acid sequence of c-type lysozyme contained 145 residues and possessed conserved catalytic residues (Glu53 and Asp72). The deduced g-type lysozyme contained 185 residues and possessed three conserved catalytic residues (Glu73, Asp86 and Asp97). qPCR analysis revealed that GrlysG and GrlysC were constitutively expressed in all examined tissues. GrlysG was most abundant in kidney and liver, while GrlysC was predominantly expressed in liver. The transcripts of GrlysG and GrlysC genes could be significantly up-regulated after Aeromonas hydrophila and poly I:C infection in the kidney and liver. The recombinant GrlysG and GrlysC proteins were successfully produced and purified. The optimal pH and temperature for rGrlysG and rGrlysC protein lytic activities was determined to be 6.5 and 32 °C, respectively. From the minimal inhibitory concentration test, the rGrlysG and rGrlysC exhibited apparent antibacterial activities against both Gram-positive and Gram-negative bacteria at different concentrations. In conclusion, the present study indicated that c-type and g-type lysozymes participated the innate immune response to A. hydrophila and virus infections in fish.
KeywordsRare minnow Lysozyme Expression analysis Lytic activity
Financial support for this study was provided by Initial Research Foundation of Yangzhou University under Grant 137011293, Doctor Initial Research Foundation of Northwest A&F University under Grant Z109021640, the opening project of Scientific Observing and Experimental Station of the Ministry of Agriculture (2015SYKF-03).
Compliance with ethical standards
Conflict of interest
Yingying Zhang, Hui Yang, Weijia Song, Dan Cui and Lixin Wang declare that they have no conflict of interest.
This article was approved by the Animal Ethics Committee of Northwest A&F University.
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