Effect of heavy oil exposure on antibacterial activity and expression of immune-related genes in Japanese flounder Paralichthys olivaceus.
Heavy oil (HO) pollution is one of the most important environmental issues globally. However, little is known about the immunotoxicity of HO in fish. We therefore investigated the effects of HO exposure on immunocompetence and expression of immune-related genes in Japanese flounder, Paralichthys olivaceus. To test immunocompetency, serum collected from the fish was mixed with Edwardsiella tarda, plated, and the resultant numbers of bacterial colonies were counted. Plates with serum from HO-exposed fish (5 d postexposure [dpe]) had significantly higher numbers of colonies than those of the untreated control group, suggesting that HO exposure suppresses immunocompetency. Downregulation of the immunoglobulin light chain (IgM) gene in HO-exposed fish at 5 dpe was detected by real-time polymerase chain reaction. These results suggest that IgM-mediated immunity is suppressed by HO exposure. We measured polycyclic aromatic hydrocarbon (PAH) concentrations in the liver of the fish. Low molecular weight PAHs were found to be taken up at high concentrations in fish liver; therefore, they are likely the cause of immune suppression in the fish.
Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan.
Jun-Young
JY
Song
Kei
K
Nakayama
Emiko
E
Kokushi
Kazuki
K
Ito
Seiichi
S
Uno
Jiro
J
Koyama
M Habibur
MH
Rahman
Yasunori
Y
Murakami
Shin-Ichi
S
Kitamura
D000818:Animals; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D020609:Edwardsiella tarda / Q000472:pathogenicity; D004781:Environmental Exposure; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D005432:Flounder / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D005648:Fuel Oils / Q000633:toxicity*; D050439:Genes, Immunoglobulin Light Chain; D007075:Immunoglobulin M / Q000235:genetics / Q000276:immunology; D008099:Liver / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000493:pharmacokinetics; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D005648:Fuel Oils; D007075:Immunoglobulin M; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical