• Development and Reproduction
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• v.11 no.1
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• pp.43-47
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• 2007

Smad proteins mediate transforming growth $factor(TGF)-{\beta}$ signaling and play a pivotal role in embryonic development. The estrogen receptor-related receptors(ERRs), which are structurally similar to estrogen receptors, are members of orphan nuclear receptor in the nuclear receptor superfamily and their functions are known to be involved in the formation of extra-embryonic ectoderm. To investigate the involvement of Smad3 and $ERR{\beta}$ like 1 in reproductive activities and embryogenesis in marine invertebrate, we examined gene expression of Smad3 and $ERR{\beta}$ like 1 in Strongylocentrotus nudus during their seasonal changes and embryonic development using real-time polymerase chain reaction. The Smad3 mRNA levels in gonad showed an increasing pattern from February to June 2004 but decreased at August(spawning season) followed by an elevation of the levels at October and December 2004. The mRNA levels of the $ERR{\beta}$ like 1 significantly elevated during the spawning season. During embryonic development, Smad3 mRNA levels at $8{\sim}16$ cell stages were significantly higher than those of other stages, whereas the mRNA of the $ERR{\beta}$ like 1 was significantly high levels at late development stages, i.e., blastular, gastrula and plutei stages. These results suggest that the Smad3 could be involved at least in part in the early cleavage stages and the $ERR{\beta}$ like 1 may play an important role in the spawning season and late developmental stage in the sea urchin.

• Development and Reproduction
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• v.14 no.4
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• pp.225-231
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• 2010

Gonadal development and reproductive cycles of red sea urchin Pseudocentrotus depressus were investigated based on the monthly variations of gonadosomatic index (GSI), gametogenesis and developmental phases of gonad. The specimens were sampled monthly in the north coastal waters of Ongpo and the south coastal waters Bubhwan of Jeju Island, Korea, from December 1994 to December 1995. Monthly changes of GSI values and reproductive cycles showed similar trends in Ongpo and Bubhwan. In females GSI values were reached the maximum in December ($17.8{\pm}4.04$ in Ongpo, $13.8{\pm}1.51$ in Bubhwan). In males GSI values were reached the maximum in December ($15.4{\pm}1.53$ in Ongpo, $13.6{\pm}1.32$ in Bubhwan). In both Ongpo and Bubhwan major spawning probably occurred between November and February when water temperatures and daylengths decrease. The histological observations of the gonads suggested that this species seemed to have a synchronous gametogenesis and one spawning season a year in Jeju Island costal waters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.421-427
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• 1995

To know the variation in the growth of the sea urchin, Pseudocentrotus depressus according to their localities, three different populations including the culture populations, the released populations, and the wild populations were investigated using the cluster analysis. For this purpose, pigment banding pattern on the genital plate was used as an age character. The population composed of the same year class was born between September 25th and October 5th every year. The population of 9 to 10 months old had no $r_1,\;whereas\;r_1$, was observed in the population of either 1 year and 10 or 11 months old, and both $r_1,\;and\;r_2$ in the population of either 2 year and 9 or 10 months old. Therefore, $r_1,\;and\;r_2$ radius were regarded as an annual ring. Growth in the culture populations was much better than that In either the released or the wild populations. However, when the cultured populations composed of 8 to 12 mm in test diameter was released to the shove near a culture farm, its growth appeared to be similar to that of the wild Populations. The wide distribution patterns of test diameter measured from the same year class of both the cultured and the wild populations were probably due to either long spawning period or growth differences between individuals. Except Yamaguchi and Cheju populations, the move closely located populations showed the more similar growth pattern. However, the growth of Cheju population appeared to be similar to that of Aba, Mogi, Toishi rather than Kasiwazima although Cheju Island was more closely located with Kasiwazima than other localities. In addition, the population of Yamaguchi, located at the highest latitute, revealed the similar growth pattern to that of Nomozaki, located at the lowest latitute.

• Development and Reproduction
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• v.11 no.3
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• pp.179-185
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• 2007

The estrogens and estrogenic endocrine disrupting chemicals(EDCs) function through a steroid nuclear receptor-mediated process and subsequently regulate the transcription of mRNA for a number of target proteins. The estrogen receptor-related receptors(ERRs), which are structurally similar to estrogen receptors, are members of orphan nuclear receptor in the nuclear receptor superfamily and their functions are known to be involved in the formation of extra-embryonic ectoderm. To investigate effects of EDCs on early embryogenesis and ERR gene expression in marine invertebrates, we examined morphological changes and the mRNA expression of $ERR{\beta}$ like 1 in sea urchin Strongylocentrotus nudus exposed to estradiol-$17{\beta}(E_2)$ or nonylphenol(NP). The $E_2$ and NP-exposed embryos showed a delayed development compared to control embryos. Furthermore, they showed abnormal embryonic developments at late stages, i.e., blastular, gastrula and plutei stages. The mRNA level of $ERR{\beta}$ like 1 at the gastrula stage was significantly lower in $E_2$ and NP-exposed embryos than those of control group. These results suggest that NP and $E_2$ are potent chemicals causing abnormal embryonic development of S. nudus through at least in part down-regulated $ERR{\beta}$ like 1.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.414-422
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• 1984

This research was conducted to evaluate the effect of polluted Oncheon Stream on the marine organisms in the Suyeong Bay. Water quality and 96 hr acute toxicity to the sea urchin, Hemicentrotns pulcherrimus by recirculation bioassay were examined from Feb. 20 to Apr. 15, 1984. The 96 hr $50\%$ effective concentration($EC_{50}$) on the attachment of the podia of the sea urchin was observed to occur at test concentrations between 40.0 and $51.0\%$ (v/v), and safe concentrations may be assumed to be within 4.0 and $5.1\%$. These values indicate as follows : 1. Oncheon Stream was extremely polluted by oxygen-demanding wastes and synthetic organic compounds from sewage and industrial waste water. 2. Linear alkylbenzene sulfonate(LAS) which has not been yet included in water quality standard was discharged above the TLm. 3. Unknown toxicity may be synergy among complex substances. In consideration of the relationship between COD values of Oncheon Stream and dilution water, the effect of toxicity of Oncheon Stream water reached to the area of the Suyeong Bay where the COD value was found to be 12.2 ppm.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.61-66
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• 2005

This experiment was conducted to compare the influences of dietary sea urchin shell powder (SUSP) supplemented to broiler diets on performance, mineral contents and blood cholesterol for 5 weeks. The experimental diets contained 21.5 and $19\%$ CP for the starting and finishing period, respectively The ME was 3,100 kcal/kg of feed in both starter and finisher diets. One hundred sixty chicks were assigned to 4 treatments with 4 replicates and fed one of 4 experimental diets containing different levels of SUSP: 1) Control (commercial feed) 2) T1 (commercial feed with $1\%$ SUSP) 3) T2(commercial feed with $3\%$ SUSP) 4) T3(commercial feed with $5\%$ SUSP). Body weight gain was higher in the T1 group when fed the starter diet (P<0.05), but was the lowest in T1 group for finishing period. Feed efficiency was not significantly different between the control and treatment groups (P>0.05). The total cholesterol of the control was higher than the treatment groups and the HDL-cholesterol were higher in T2 and T3. However, effects of diets containing graded levels of SUSP on LDL-cholesterol and triglyceride contents were not found (P>0.05). The SUSP diets were increased significantly the Fe, Zn and Ca contents of chicken meat, and tended to increase total mineral contents. In conclusion, dietary supplementation of SUSP to broiler diets could be applied to the enhancement of Ca, Fe and total mineral contents levels in chicken meat.

• Animal Systematics, Evolution and Diversity
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• v.22 no.1
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• pp.105-108
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• 2006

Some sea urchins were collected from the subtidal rocky bottom along the coastal line in Jeju Island by SCUBA diving in April 2005 and identified on the basis of their morphological characteristics. Among them, Asthenosoma ijimai Yochiwara, 1897 was newly recorded from Korea and redescribed based on the specimen collected at 20m deep in southern breakwater of Seogwipo harbor. The order Echinothurioida including family Echinothuriidae and genus Asthenosoma was firstly recorded in Korea. Seventeen species of echinoids are reported to be distributed in Jeju Island of Korea.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.80-87
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• 2021

In this study, the toxic effects of PFOA and PFOS potassium salt on Mesocentrotus nudus using 10 min-fertilization rate and 48 h-normal embryogenesis were confirmed through the calculation of toxicity values such as Non-observed effective concentration, Low-observed effective concentration, and 50% of effective concentration. The case of 10 min-fertilization rate and 48 h-normal embryogenesis showed the concentration-dependent reduction pattern when exposed to PFOA and PFOS potassium salt, in tested concentration, respectively. The EC50 values of 10 min-fertilization rates for PFOA and PFOS potassium salt were 1346.43 mg/l and 536.18 mg/l, respectively, and the EC50 values of 48 h-normal embryogenesis were 42.67 mg/l and 17.81 mg/l, respectively. Both toxicity test methods showed high toxicity sensitivity to PFOS potassium salt. Recent studies have shown that the concentration of PFOA and PFOS in the marine environment has continuously decreased, and it is not enough to show acute toxicity to sea urchin. However, PFOA and PFOS have a very long half-life and can accumulate throughout the life of marine life, so it is still observed at a high concentration in shellfish. Therefore, a study on chronic toxicity through the whole-life cycle of marine organisms in coastal environments should be needed.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.158-158
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• 2003

Bioassays using gametes of sea urchins are widely used in ecotoxicological assessments of marine environments. Since most of sea urchin species in Korean coastal water spawn from spring to autumn, bioassay with them during the winter is impossible. In the course of developing standard methods for bioassays with Korean species, we found a winter-spawning starfish, Asterias amurensis, Since reproductive mode of asteroids is similar to echinoids, the bioassay protocol for sea urchins could be applied similarly to the starfish. Here, we tested and determined several conditions for the acceptability of bioassay with A. amurensis. The least required time for formation of fertilization membrane of fertilized eggs to be easily distinguished from unfertilized ones was 60 min. The threshold of sperm to egg ratio that could make acceptable fertilization rates in controls was 3000. The allowed time for manipulation of sperm after dilution in seawater was at most 3 hr. The optimal exposure time of sperms when the response against toxicant solution was relatively stable was in the range of 20-60 min. The tolerance range of sperms to the salinity of test solution was 26-38 psu. The sensitivity of A. amurensis sperm was intermediate among marine organisms commonly used in aquatic toxicity tests. The sperm bioassay with A. amurensis can be satisfactorily applied to toxicity assessments of marine environments.

• Animal cells and systems
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• v.8 no.1
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• pp.13-18
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• 2004

Pseudanthessius spinosus n. sp. is described as an associate of the sea urchin Clypeaster japonicus Doderlein from Cheju Island in Korea. The new species may be easily distinguished from its congeners by having four spines and five setae on the third exopodal segment of leg 4. It is the second known species of the genus from Korean waters.