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Choi Y.J.,Korea Maritime and Ocean University | Yang S.-G.,Future Aquaculture Research Institute | Jung M.-M.,Future Aquaculture Research Institute | Kim B.-S.,Future Aquaculture Research Institute | And 2 more authors.
Molecular and Cellular Toxicology | Year: 2015

Selenium (Se) is an essential element, known to bioaccumulate to toxic levels in aquatic environments. Here, we tested the toxic and physiological stress response of goldfish, Carassius auratus exposed to different concentrations of Se for 120 h. At the end of the experiment, the toxic stress indicators [metallothionein (MT), aminotransferase/aspartate (AspAT and AlaAT), and gill Na+/K+-ATPase] and other stressrelated parameters [corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and glucocorticoid receptors (GRs) mRNA and activity and/or plasma ACTH, cortisol, glucose, hydrogen peroxide (H2O2), and muscle lipid peroxidation (LPO)] were significantly higher in specimens exposed to 3 and 4 mg/L of Se than in those exposed to lower concentrations (0 and 2 mg/L). These results indicated that 3 and 4 mg/L Se concentration can induce an acute toxic and physiological stress response in aquarium conditions. © 2015, The Korean Society of Toxicogenomics and Toxicoproteomics and Springer Science+Business Media Dordrecht.

Kim N.N.,Korea Maritime and Ocean University | Choi Y.J.,Korea Maritime and Ocean University | Lim S.-G.,Future Aquaculture Research Institute | Jeong M.,Future Aquaculture Research Institute | And 2 more authors.
Comparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology | Year: 2015

Studies of memory formation have recently concentrated on the possible role of N-methyl- d-aspartate receptors (NRs). We examined changes in the expression of three NRs (NR1, NR2B, and NR2C), olfactory receptor (OR), and adrenocorticotropic hormone (ACTH) in chum salmon Oncorhynchus keta using quantitative polymerase chain reaction (QPCR) during salinity change (seawater. →. 50% seawater. →. freshwater). NRs were significantly detected in the diencephalon and telencephalon and OR was significantly detected in the olfactory epithelium. The expression of NRs, OR, and ACTH increased after the transition to freshwater. We also determined that treatment with MK-801, an antagonist of NRs, decreased NRs in telencephalon cells. In addition, a reduction in salinity was associated with increased levels of dopamine, ACTH, and cortisol (in vivo). Reductions in salinity evidently caused NRs and OR to increase the expression of cortisol and dopamine. We concluded that memory capacity and olfactory imprinting of salmon is related to the salinity of the environment during the migration to spawning sites. Furthermore, salinity affects the memory/imprinting and olfactory abilities, and cortisol and dopamine is also related with olfactory-related memories during migration. © 2015 Elsevier Inc.

PubMed | Future Aquaculture Research Institute and Korea Maritime and Ocean University
Type: | Journal: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology | Year: 2015

Photoperiod is considered the most important factor that entrains animal rhythms, including the reproductive cycle. The present study tested differences in sex maturation and sex steroid hormones of yellowtail damselfish (Chrysiptera parasema) exposed to a white fluorescent bulb (12L:12D and 14L:10D) or long-afterglow phosphorescent pigment (LumiNova sheet) for 4 months. At the end of the experiment, in the phosphorescent group, mRNA expressions of gonadotropin hormones [(GTHs, including gonadotropin (GTH) and luteinizing hormone (LH) )], estrogen receptor (ER), and vitellogenin were significantly higher than in the photoperiod groups (12L:12D and 14L:10D), and these results are consistent with those of Western blotting for protein expression. Furthermore, in the phosphorescent group, plasma FSH, LH, and estradiol-17 (E2) levels were significantly higher than in the photoperiod groups. However, plasma melatonin levels were significantly lower than in the photoperiod groups. Because LumiNova sheets continue to emit green light (520 nm) for approximately 2h after sunset, the extended light conditions probably contributed to reproductive ability in the experimental fish. In conclusion, long-afterglow phosphorescent pigment can be used for energy-efficient aquaculture to regulate the reproduction of fish, although its effect needs to be evaluated in other species.

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