title: Naringenin suppresses Edwardsiella tarda infection in GAKS cells by NanA sialidase inhibition.
abstract: Edwardsiella tarda (E. tarda) is a gram-negative bacterium, which causes Edwardsiellosis in aquaculture. Previous studies indicate that E. tarda NanA sialidase plays crucial roles in infection through the desialylation of glycoproteins in fish cells. On the other hand, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid, classic sialidase inhibitor, negatively regulates E. tarda infection of goldfish scale GAKS cells. Here, to development the suppression model of E. tarda infection for aquaculture application, the possibility of NanA inhibitory activities in citrus phytochemicals was evaluated as citrus extracts have widely been used as a supplement in fish diets for the improvement of meat quality. Some flavanones such as naringenin, hesperetin, hesperidin and naringin showed sialidase inhibitory activity toward recombinant NanA in vitro. Among them, naringenin showed the most potent inhibitory activity and its inhibitory pattern was non-competitive. Naringenin significantly suppressed E. tarda infection in GAKS cells at 200 and 400 μM without bactericidal effect on E. tarda. On the other hand, naringin, glycosylation form of naringenin, showed slight suppression of E. tarda infection toward GAKS cells, suggesting the glycosides on flavanone could be important for NanA inhibition. Fluorescence microscopy analysis verified that number of invading E. tarda in GAKS cells was declined by naringenin treatment. The present study exhibited the possibility of naringenin as an effective ingredient in fish diet for the inhibition of E. tarda infection.
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Shinyoshi
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kamada
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Matsusaki
authors.affiliation: Department of Fisheries, Mzuzu University, Mzuzu, Malawi; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Petros Kingstone
authors.initials: PK
authors.lastname: Chigwechokha
authors.affiliation: Faculty of Fisheries, Kasetsart University, Bangkok, Thailand.
authors.forename: Supawan
authors.initials: S
authors.lastname: Tepparin
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Araki
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Komatsu
authors.affiliation: Faculty of Fisheries, Kagoshima University, Kagoshima, Japan; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan. Electronic address: shiozaki@fish.kagoshima-u.ac.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shiozaki
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002957:Citrus / Q000737:chemistry*; D020609:Edwardsiella tarda / Q000187:drug effects / Q000502:physiology; D004756:Enterobacteriaceae Infections / Q000235:genetics / Q000382:microbiology / Q000662:veterinary*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005393:Fish Diseases / Q000235:genetics* / Q000382:microbiology; D044950:Flavanones / Q000494:pharmacology; D006054:Goldfish; D019158:N-Acetylneuraminic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D009439:Neuraminidase / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D044950:Flavanones; C036137:2-deoxy-2,3-dehydro-N-acetylneuraminic acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; C005273:naringenin
keywords: Edwardsiella tarda; Infection; NanA; Naringenin; Sialidase