Min-Min Jung

Effects of waterborne selenium on toxic and physiological stress response in goldfish, Carassius auratus

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.

Variations in the antioxidant system and circadian rhythms of goldfish, Carassius auratus, exposed to ammonia: profile of the effects of green LED spectra

Abstract The present study evaluated effects of green light emitting diode (LED) spectra on oxidative stress and circadian rhythms in goldfish exposed to various concentrations (0.25 and 0.5 mg/L) of NH3, under a white fluorescent bulb (control; simulated natural period) and green LED light. We measured mRNA expression and activity of antioxidant enzymes (superoxide dismutase and catalase) and mRNA expression of circadian rhythms (period 2), in addition to levels of plasma hydrogen peroxide, cortisol and melatonin. Damage to nuclear DNA was assessed using the comet assay. All stress indicators and melatonin were significantly lower in the green LED group than in the control group. With an increase in the concentration of ammonia, the observed effects became even more significant and generally increased with time. Comparatively, damage to the nuclear DNA was greater in the 0.5 mg/L NH3 group, and lower in the green LED group. The Period 2 mRNA expression reduced as increasing ammonia treatment but increased as green LED exposed. We have suggested that Green LED reduced levels of oxidative stress, which suggests an antioxidant effect against NH3 toxicity. Additionally, ammonia is affected the circadian rhythms and the green LED wavelength is able to regulate effectively the circadian rhythm.

Effects of waterborne copper on toxicity stress and apoptosis responses in red seabream, Pagrus major

BackgroundsThere has been an increasing trend of copper (Cu)-based aquaculture industry in the world, and it is necessary to evaluate the effect of copper ion exposure on water pollution. This study was aim to determine the critical concentration of toxic copper in adult red sea bream.MethodsTherefore, we investigated the effects of Cu toxicity on physiological stress and apoptosis exposed to various concentrations (10, 20, 30, and 40 μg/L). We measured physiological stress-related (corticotrophin- releasing hormone, adrenocorticotropic hormone, cortisol, and glucose), other toxic stress-related (metallothionein and Na+/K+-ATPase), and apoptosis-related (caspase-3 and hydrogen peroxide) parameters. In addition, we confirmed apoptosis.ResultsPhysiological parameters were significantly increased from Cu concentration of 30 μg/L or more. However, no significant differences were observed after exposures at 10 and 20 μg/L. In addition, apoptotic cells were detected after exposure to 30 μg/L.ConclusionThe results of this study indicate that high concentrations induce stress and apoptosis compared to normal conditions.

Effect of different wavelengths of light on the antioxidant and immunity status of juvenile rock bream, Oplegnathus fasciatus, exposed to thermal stress

We investigated the effect of light wavelengths on antioxidant and immunity parameters in juvenile rock bream, Oplegnathus fasciatus, exposed to thermal stress (25 and 30°C). We exposed the fish to light emitting diodes (LEDs) emitting green (520 nm) and red light (630 nm) of 0.25 and 0.5 W/m2 intensity, and measured the activity, and mRNA and protein expression levels of the antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase. We also determined the levels of plasma hydrogen peroxide (H2O2), melatonin, and lysozyme. Furthermore, the mRNA and protein levels of caspase-3 were measured and terminal transferase dUTP nick end labeling (TUNEL) assays were performed. We observed that mRNA expression and activities of antioxidant enzymes and plasma H2O2 levels were significantly higher after exposure to high temperatures. However, increases in these parameters were significantly lower after exposure to green LED light. The plasma melatonin and lysozyme levels were significantly lower in the different groups after exposure to high temperatures; however, in groups exposed to green LED light, their levels were significantly higher than those in the control group. The expression pattern of caspase-3 mRNA was similar to that of H2O2. The TUNEL assay showed that apoptosis was markedly higher at higher water temperatures than that at 20°C. These results indicate that high water temperatures induce oxidative stress and decrease the immunity in juvenile rock bream but green LED light inhibits the rise in oxidative stress and combats the decrease in immunity and should, thus, be useful in the culture of rock bream.

Gene discovery in the finger leather coral Sinularia notanda by construction and sequencing of a normalized cDNA libary

The transplantation of coral fragments is one of methods that restore coral communities. To form coral colonies, the fragmented corals initiated skeletal extension from the cut-edge of fragment then success the settlement. In order to understand the molecular events underlying fragment adhesion and settlement, we constructed a normalized cDNA library and generated and annotated expressed sequence tags (ESTs) from the fragmented adult polyps of soft coral Sinularia notanda. We generated 3251 high-quality ESTs with an average length of 580 bp and the EST cluster and assembly analyses produced 2796 unigenes, including 2487 singletons and 309 contigs. Of the known genes, 55 genes were sel ected to be involved in polyp fragment adhesion and settlement based on Gene Ontology (GO) classification. Notably, two EST clones were identified to show homology with galaxin gene which was demonstrated as coral specific calcifying protein of organic matrix. These EST sequences can provide utility as molecular markers in molecular and genetic studies of S. notanda and other soft coral.

Health Evaluation and Fish Population Analysis by Using LEHA (Lentic Ecosystem Health Assessment) Model

Health assessment of aquatic ecosystem was investigated by using LEHA (Lentic Ecosystem Health Assessment) model method with habitat fish population structure analysis in this study. The investigation was two comparison spots (St 1; floating island, St 2; 500 m away site from st 1) in the Habcheon lake of Korea. As results, health evaluation of Habcheon lake ecosystem was fair grade of LEHA scores base on metric values in both place (30 score in st. 1 and 32 score in st. 2).

Environmental Conditions as Accidental Nesting Place of Seaturtle Located in Jeju Island of Korea

Jungmun beach was confirmed only one beach as a nesting place of seaturtles in Jeju of South Korea. We investigated the environment conditions for nesting of seaturtles (sites 1, 2) to target as the spawning grounds of accidental nesting place. Sand temperatures of beaches at 5 cm above and 10, 30 and 50 cm below the surface of beach were measured at intervals of approximately 10 days during June to December. These data indicated that the optimum (over ) sand temperature for spawning and hatching of seaturtles in the sites 1 and 2 from June 23 to September 29, 2008 and from June 23 to October 17, 2008, respectively. Also, maintained the optimum coastal water temperature (above ) for seaturtles maintained from June 23 to November 17, 2008. Therefore, Jungmun beach could be the possible spawning grounds of accidental nesting place, where the landed seaturtles and hatched young seaturtles could be survived successfully.

Observation and Record of Sea Turtles in Bycatch and Stranding from Jeju Island of Korea

Bycatch and stranding of sea turtles from Jeju coastal water of Korea were monitered from 2008 to 2009. A total of 41 sea turtles, consisting of 12 greens (Chelonia mydas), 3 loggerheads (Caretta caretta), 1 hawksbill (Eretmochelys imbricata) and 25 unidentified species, were recorded and observed in those area. Reported stranding and bycatch reached to a peak in August. The largest number of bycatch occurred in the coastal waters around Aewol-eup located in northwest area of Jeju Island. Most of the bycatch were taken by set nets and gill nets, which prevailed over the fishing grounds in the coastal waters of the Jeju Island. It is suggested that an appropriate monitoring system be necessary to conserve endangered sea turtle species in Jeju of Korea.