• Development and Reproduction
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• v.7 no.1
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• pp.9-13
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• 2003

A series of experiments were conducted to compare the effects of various diluents in cold storage on the sea urchin, Hemicentrotus pulcherimus sperm. Various diluents of glucose solutions, artificial sea water(ASW) and 50% ASW were used to store the sperm at 4$^{\circ}C$. The storage effect was evaluated using sperm activity index(SAI), survival rate of sperm and fertilization rate to egg. ASW and 1.2 M glucose were found to be better diluents which maintained high motility and survival rate of sperm f3r a storage period of 30 days. Optimal pH of diluent to store the sperm at 4$^{\circ}C$ is 7.0∼8.0. In order to keep high SAI and survival rate of sperm, addition of 400 ppm neomycin into the diluent revealed the best storage results.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.461-462
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• 2002

• Journal of Aquaculture
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• v.11 no.3
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• pp.401-419
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• 1998

The structure of benthic algal flora and feeding behavior of sea urchins (Anthocidaris crassispina and Hemicentrotus pulcherrimus), were investigated from the eight different locations along the coast of Cheju Island, Korea. Biomass distribution and dominance of the algal communities were studied in relation to the gut contents and population parameters of the sea urchins. As a result, although the largest algal biomass and biological characteristics of sea urchins, such as test diameter, test hight, body weight, gonad weight, etc. This inhdicated that sea urchins would not be dependednt sorely on the abundance of algal foods, and they might feed on other food items. In order to know such a trend with regard to food selectivity, the diets consumed by sea urchins were analyzed, and it was found that they were composed of benthic and drifted algae, various animal components (sponges, bryozoans, crustaceans, and various unidentified capsulated eggs, etc.) and biets turned out to be smaller than might be expected, and it is postulated that sea urchins were not likely to be the major grazing animals for the formation of algal bed and also canopy deterioration, so-called "white incrustation."

• Journal of Marine Life Science
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• v.5 no.2
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• pp.43-50
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• 2020

The aim of this study is toxicity assessment using two types of sea urchins (H. pulcherrimus, M. nudus) that can representative primary consumers in potential coastal environments pollutants, Zinc undecylenate (ZU), which is used for various purposes, such as pharmaceutical agents and anti-bacterial and anti-fungi. The Fertilization rate and normal embryogenesis rate of H. pulcherrimus and M. nudus were concentration-dependent decreased. Besides, EC₅₀ of fertilization rate with H. pulcherrimus and M. nudus were 11.27 mgl^-1 and 1.48 mgl^-1, and EC₅₀ of normal embryogenesis were 0.94 mgl^-1 and 3.78 mgl^-1. NOEC of normal embryogenesis were 0.20 and 0.78 mgl^-1, respectively. In addition, to find the safety criteria of the ZU on the marine environment. PNEC value was 0.0094 mgl^-1, calculated using the toxicity values of two species of sea urchin derived from this study and the acute toxicity results of the coastal area through literature research. The above results will be used as basic data for establishing environmental protection strategies for marine environmental pollutants.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.251-257
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• 2011

Cobalt is a naturally occurring element found in rocks, soil, water and/or is among the harmful pollutants as generated by industrialized. In the environment, cobalt has two oxidation states, cobalt (II) (Co (II)) and cobalt (III) (Co (III)). If coastal water is contaminated by cobalt, it through the food chain can have an impact on marine ecosystems. Therefore, we examined the gametotoxic and embryotoxic effects of Co (II) at various concentrations (10, 100, 500, 1000, 2500 ppb) in the sea urchin $Hemicentrotus$ $pulcherrimus$. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiment was begun within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. The fertilization rates in the control condition (not including Co (II)) and experimental group were not significantly changed. The embryo development rates in the control condition were greater than 90% and were significantly decreased with concentration dependent manner. The normal embryogenesis rate was significantly inhibited in exposed to cobalt (II) ($EC_{50}$=71.84 ppb, 95% Cl=16.71-203.36 ppb). The NOEC and LOEC of normal embryogenesis rate were <10 ppb and 10 ppb, respectively. These results suggest that the early embryo stages of $H.$ $pulcherrimus$ have toxic effect at greater than 10 ppb of Co (II) concentration.

• Journal of Aquaculture
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• v.16 no.2
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• pp.94-98
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• 2003

Effect of temperature (5, 10, 15, 18, 21$^{\circ}C$) on pre-and post-embryonic development of the sea urchin Strongylocentrotus intermedius was studied. The egg, which measured 122.5 ${\mu}{\textrm}{m}$, became globular. At 18$^{\circ}C$, it attained 4 celled stage at 3 hours after fertilization, hatched after 15 hours, 4-armed larval stage after 3 days and 8- armed larval stage after 20 days. The relationships between temperature (WT) and time (1, hour) required for each of the selected developmental stages are: Hatching: 1/t=0.0036WT+0.0088 Pyramid: 1/t=0.0014Wl-0.0016 4- armed: 1/t=0.0009WT-0.0020 6- armed: 1/t=0.0004WT-0.0005 8-armed : 1/t=0.0002WT+0.0002 Biological minimum temperature for the egg and larval development is calculated as 1.61$^{\circ}C$.

• Journal of Aquaculture
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• v.13 no.2
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• pp.169-174
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• 2000

Reproductive cycle of U. unicinctus was studied from September 1998 to August 1999, using gonadosomatic index (CSI) as an indicator. In November, the CSI values were maximum for male (6.2) and female (7.0), respectively; the values were lowest for them (1.0 and 0.5) during the successive february. Subsequently, they rapidly increased and attained peak by March-April. The values decreased again in both sexes and remained unchanged until August. The index increased in October to attain the peak by November. The CSI values clearly indicated that there are two spawning events in a year, namely the first one during April-May and the second one in December. Reproductive cycle was classified into the following successive stages: in female, multipication (January~February, June ~Setember), maturation (March~April, November), spent (May and December), degeneration and resting (June and January), and in male, multiplication January ~ february, June ~September), maturation (March~April, October~November), spent (May and December) and degeneration and resting (January and June). Histological observations revealed that oocytes in the ovary matured simultaneously in November and March. At the same time, the envelopes of matured testis became thinner than those in the early stage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1537-1543
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• 2011

We investigated the anti-diabetic effects of Hemicentrotus pulcherrimus (sea urchin, SU) shells on non-obese type 2 diabetic Goto-Kakizaki (GK) rats. We measured body weight, blood glucose, and plasma insulin levels and conducted an oral glucose tolerance test (OGTT). The SU shells (100 and 200 mg/kg) significantly reduced the blood glucose of GK rats from 203.8${\pm}$29.8 mg/dL to 138.5${\pm}$21.2 mg/dL at after 4 weeks of daily oral administration. However, plasma insulin levels at the same time were not changed by treatment with SU. During the OGTT, the SU-treated GK rats maintained a lower blood glucose level than the control group for 15 to 120 min. Based on these results, SU shells are considered to be effective in improving glucose tolerance. These results suggest that SU shells have unique properties to lower blood glucose, raise insulin sensitivity, and improve insulin resistance in GK rats.

• The Korean Journal of Zoology
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• v.28 no.2
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• pp.71-84
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• 1985

Syntheses of RNA and protein were studied to examine changes in activating stored mRNAs during the early development of a sea urchin, Hemicentrotus pulcherimus. The rates of RNA and protein syntheses are very low in the unferilized eggs but the protein synthesis is activated upon the fertilization, while RNA synthesis remains still inactive at the same stage. These rates increase drastically at the blastula and gastrula stages, although the increases are not exactly in parallel. The protein synthesis was found to be also changing in quality during the early development from the studies by the two-dimensional gel electrophoresis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.136-145
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• 1987

From the sea-urchin, Hemicentrotus pulcherrismus, we have purified by four column chromatographic steps for DNA polymerase $\alpha$ activity. The molecular weight of DNA polymerase u was determined to be around 137,000-138,000 by Sephadex G-200 gel filtration and SDS-polyacrylamide gel electrophoresis. The purified enzyme had the optimal activity at pH 7.4. This enzyme showed to be a function of the metal ion $K^+,\;Na^+$\;and\;Mg^{2+}$ employed as activators, the optimum $K^+$\;or\;Na^+ concentration were 20 mM or 25mM and the optimum $Mg^{2+}$ concentration was 10 mM. The enzyme activity was inhibited by N-ethyl-maleimide, aphidicolin, cytosine $\beta-D-arabinofuranoside$ 5'-triphoshate (ara CTP) and phosphonoacetic acid.