Identification and Pathogen Stimulation Patterns of Neuronal Nitric Oxide Synthase (nNOS) in Black Rockfish ( Sebastes schlegelii )

Neuronal nitric oxide synthase (nNOS) was the producer of nitric oxide (NO) which played important gas messenger molecules in biological process. It also can take effect as immune regulation molecule in organism. Black rockfish ( Sebastes schlegelii ) is an important economic fish which were widely farmed in East Asia countries. Meanwhile, the pathogenic bacteria such as the Edwardsiella tarda and Vibrio anguillarum in seawater always brought serious obstacles to their healthy growth. In order to explore the expression pattern of nNOS gene under the pathogen stimulation and predict its immune function, the nNOS gene in black rockfish named SsnNOS was identified. It was 3780 bp in length, located on chromosome 6, and contained 27 coding domain sequence (CDs). According to the phylogenetic analysis, the SsnNOS showed closest relative to the counterpart gene of swamp eel ( Monopterus albus ). Meanwhile, analysis of SsnNOS expression in various healthy tissues showed that SsnNOS expression level was highest in healthy brain tissues, followed by intestinal tissues. In addition, SsnNOS showed significant expression changes in response to stimulation by two pathogens. Particular in gill, the expression of SsnNOS after pathogenic stimulation increased significantly. The Elisa analysis showed the SsnNOS content in gills was much higher than that in other tissues at all time points. Moreover, the expression patterns of SsnNOS in brain, intestine and kidney after stimulation by pathogens showed a distinct expression pattern which first down-regulated and then up-regulated. Therefore, the SsnNOS may be an important signaling molecule for fish to respond rapidly in immune stimulation.