Edwardsiella piscicida is a new species discovered within the group of organisms traditionally classified as Edwardsiella tarda. We present draft genome sequences of two variant strains of E. piscicida, JF1305 and RSB1309. Differences in protein-coding sequence between these isolates are associated with virulence, disease, and defense, suggesting differences in pathogenicity.
Vaccination with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of Edwardsiella tarda has been demonstrated to have cross-protection against some other bacterial pathogens. We prepared a recombinant protein and pcDNA4 expression vector of GAPDH of E. tarda and injected those to 0-age yellowtail Seriola quinqueradiata to evaluate their protective efficacies against Nocardia seriolae. The 60-d survival rates ranged from 0% to 6.7% among vaccinated and control groups, suggesting that the protein and expression vector of E. tarda GAPDH had no protective effect against nocardiosis. However, the copy numbers of the 16S ribosomal RNA gene of N. seriolae were significantly lower in the gill, kidney, and spleen of vaccinated fish 9 and 18 days post-infection compared with those in the control group that was also challenged with N. seriolae. Additionally, the CC chemokine, major histocompatibility complex class II α antigen, interleukin 1β, and immunoglobulin M genes were significantly upregulated in the vaccinated groups. Four predicted B-cell epitopes of GAPDH in E. tarda, which may play an important role in cross-protection, differed in amino acid sequences from those of GAPDH in N. seriolae. This may explain the lack of a protective effect of E. tarda GAPDH against N. seriolae.
Streptococcus parauberis strain SK-417 was isolated from the brain of a diseased Sebastes ventricosus, collected from an aquaculture farm in April 2013 in Kagoshima Prefecture, Japan. The draft genome sequence, obtained with a 454 GS Junior sequencing system, consists of 33 large contigs of >500 bp, totaling 1,958,836 bp, and has a G+C content of 35.4%.
