Abstract
Fish nocardiosis is a chronic, systemic, granulomatous disease in aquaculture. Nocardia seriolae has been reported to be one of the main pathogenic bacteria of fish nocardiosis. There are few studies on the associated virulence factors and pathogenesis of N. seriolae. Alanine dehydrogenase (ALD), which may be a secreted protein, was discovered by analysis using bioinformatics methods throughout the whole genomic sequence of N. seriolae. Nevertheless, the roles of ALD and its homologs in the pathogenesis of N. seriolae are not demonstrated. In this study, the function of N. seriolae ALD (NsALD) was preliminarily investigated by gene cloning, host cell subcellular localization, secreted protein identification, and cell apoptosis detection. Identification of the extracellular products of N. seriolae via mass spectrometry (MS) analysis revealed that NsALD is a secreted protein. In addition, subcellular localization of NsALD-GFP recombinant protein in fathead minnow (FHM) cells showed that the strong green fluorescence co-localized with the mitochondria. Moreover, apoptosis assays demonstrated that the overexpression of NsALD induces apoptosis in FHM cells. This study may lay the foundation for further exploration of the function of NsALD and facilitate further understanding of the pathogenic mechanism and the associated virulence factors of N. seriolae.
Highlights
Fish nocardiosis, a chronic systemic granulomatous disease, has great influence on both marine and freshwater aquaculture industry [1, 2]
Sequencing analysis showed that the total length of the open reading frame (ORF) of N. seriolae ALD (NsALD) was successfully acquired, which encoded an alanine dehydrogenase homolog
The results of sequencing analysis revealed that the ORF of the NsALD gene (GenBank: 61148960) was 1,188 bp encoding 395 amino acid sequences, with alanine dehydrogenase/PNT, N-terminal domain, and alanine dehydrogenase NAD-binding and catalytic domains, which belong to the NADB-Rossmann superfamily (Figure 1B)
Summary
A chronic systemic granulomatous disease, has great influence on both marine and freshwater aquaculture industry [1, 2]. N. seriolae has been most frequently reported as the main pathogen in the last 30 years. Nocardia seriolae can infect the immunodeficient fish via wounds, the gills, and feeds [4]. The symptoms of diseased fish include skin ulceration and serious sarcoidosis caused by a mass of white nodules in the gills, spleen, liver, head kidney, and trunk kidney [5]. N. seriolae was able to infect about 42 kinds of marine and freshwater fish, such as blotched snakehead (Channa maculata), amberjack (Seriola dumerili), yellowtail (Seriola quinqueradiata), snubnose pompano (Trachinotus blochii), golden pompano (Trachinotus ovatus), Alanine Dehydrogenase of Nocardia seriolae largemouth bass (Micropterus salmoides), large yellow croaker (Larimichthys crocea), and red drum (Sciaenops ocellatus) [3, 6– 8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
