Comparative transcriptional analysis reveals distinct expression patterns of channel catfish genes after the first infection and re-infection with Aeromonas hydrophila

Abstract

To determine whether transcriptional levels of channel catfish (Ictalurus punctatus) genes are differentially regulated between a first infection with Aeromonas hydrophila and a re-infection, suppression subtractive hybridization (SSH) was performed in this study using anterior kidney cDNA after the re-infection as tester. Of the 96 clones isolated from the SSH library, 28 unique expressed sequence tags (ESTs) were obtained, of which eight were confirmed to be slightly but significantly (P < 0.05) more up-regulated by the re-infection at 6 h post infection (hpi). Expression kinetics studies at 3, 6, 12, 24, and 48 hpi revealed that the eight ESTs were significantly (P = 0.016) more up-regulated by the first infection, with a major peak at 3 hpi. A total of 96 genes reported in literature to be up-regulated by bacterial infections were selected and subjected to expression analysis at 3 hpi. Of the 96 selected genes, 19 were found to be significantly (P < 0.05) induced by A. hydrophila after the first infection and the re-infection. The 19 genes belonged to the following five main categories: 1) toll-like receptor (TLR2, TLR3, TLR5, TLR21); 2) antimicrobial peptide (NK-lysin type 1, NK-lysin type 2, NK-lysin type 3, cathepsin D, transferrin, hepcidin); 3) cytokine or chemokine (interleukin-1β, interleukin-10, tumor necrosis factor α, chemokine CXCL-10); 4) signaling proteins (cadherin EGF LAG seven-pass G-type receptor 1, very large inducible GTPase 1, arginine deiminase type 2, lymphokine-activated killer T-cell originated protein kinase); 5) lysozyme (lysozyme c). Overall, the total 27 genes (8 ESTs plus the 19 selected genes) were significantly (P < 0.001) more induced by the first infection. Peaked expression of lysozyme c and serum lysozyme activity after the first infection were seen at 24 hpi, whereas that after the re-infection were seen at 12 hpi, suggesting that both innate and adaptive immunity were involved in the defense against the re-infection of A. hydrophila.

Effect of Dietary Acidolysis-Oxidized Konjac Glucomannan Supplementation on Serum Immune Parameters and Intestinal Immune-Related Gene Expression of Schizothorax prenanti

“…S. prenanti is considered to be a good candidate for freshwater aquaculture in China due to its delicious meat and high market value. However, S. prenanti is susceptible to different diseases, such as infection from motile Aeromonas septicaemia [ 1 ], which can affect the quality of its flesh. Recently, the problem of infected fish has been reported from some fish farms.…”

Expression of immune genes in skin of channel catfish immunized with live theronts of Ichthyophthirius multifiliis

“…A total of 21 genes was analysed based on the published reports of immune genes affected by parasite and/or bacterial infection in channel catfish, including genes of immunoglobulin (IgM and IgD heavy chain), cell receptor, cytokine, complement factor, toll‐like receptor and the V(D)J genes (RAG1 and RAG2) . For this study, the primers were designed using the primer‐BLAST program (http://www.ncbi.nlm.nih.gov/tools/primer-blast/) and listed in Table .…”

Molecular immune response of channel catfish immunized with live theronts of Ichthyophthirius multifiliis

“…Sixteen immune related genes were selected in this study based on published reports of immune genes affected by parasite and bacterial infection, including genes of immunoglobulin, immune cell receptor, cytokine, complement factor and toll-like receptor [18,19,21,22,23]. The genespecific primers were designed with the aid of Primer3 (http://biotools.umassmed.edu/bioapps/primer3_www.cgi) and are listed in Table 1.…”

“…The genespecific primers were designed with the aid of Primer3 (http://biotools.umassmed.edu/bioapps/primer3_www.cgi) and are listed in Table 1. Channel catfish 18S ribosomal RNA gene primers [23] were included as an internal calibrator to normalize cDNA quantities. Primers for immune genes were synthesized by Sigma Aldrich (St. Louis, MO).…”