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메뉴피조개, Scapharca broughtonii (Schrenck) 정자의 동결보존 위해 동결높이에 따른 예비동결 (0, 2, 4, 6 cm), 희석제 (150 mM NaCl, 300 mM glucose, Ringer's solution)와 동해방지제(glycerol, dimethylsulfoxide (DMSO), dimethylacetamide (DMA), methaol) 에 따른 효과를 정자의 운동성과 생존율로 비교하였다. 피조개 정자 동결보존에 있어 예비동결은 액체질소표면으로부터 2 cm가 가장 효과적이었으며, 희석제로는 Ringer's solution이 동해방지제로는 DMSO 10% 농도가 가장 적합하였다.
This study was conducted to investigate protocol standardization for spermatozoa cryopreservation of the Scapharca broughtonii (Schrenck). Among the freezing rates, freezing at a height of 2 cm above liquid nitrogen surface for 5 minute gave higher activity and survival rate. Among the various diluents, Ringer's solution was the best for S. broughtonii sperm cryopreservation. The suitability of cryoprotectants dimethylsulfoxide (DMSO), dimethylacetamide (DMA), glycerol and methanol were tested against three freezing rates. DMSO gave significantly higher activity and survival rates than others.
개조개 표본은 동중국해의 진해만에서 잠수선에 의해 어획된 것을 2002년 1월부터 12월까지 매월 120개체씩 채집된 것이다. 생식소 발달단계는 비활성기 (11월-12월), 초기활성기 (11월-이듬해 1월), 후기활성기 (12월-이듬해 2월), 성숙기 (2월-5월과 10월), 산란기 (4월-12월) 등 5단계로 구분되었다. 주산란시기 6월부터 8월까지이었다. 성숙각장은 71-85mm로 추정되었다. 암컷과 수컷 성비는 유의한 차가 없었으므로 1:1이었다.
Reproductive biology of the purplish Washington clam, Saxidomus purpuratus was investigated based on the samples captured in Jinhae Bay, the East China Sea from January to December 2002. The gonad index (GI) began to increase in January, reached the maximum value in March. The reproductive cycle of this species can be divided into five successive stages: the early active stage (from November to January), the late active stage (from December to February), the ripe stage (from February to May and October), the spawned stage (from May to December), and inactive stage (from November to December). The spawning period was from April to December, and the main spawning occurred between June and August. The shell length at 50% group maturity was estimated to be 71.85 mm. The Sex ratio of this species was not significantly different a 1:1 sex ratio (P > 0.05).
경기만 4개 지역 바지락 양식장의 저질조성에 따른 바지락 서식밀도 및 형태적 특성에 대하여 2007년 1월부터 12월까지 조사하였다. 저질조성에서 외리와 종현은 니사질로 분급이 양호하였으며, 백미리는 역질니토로 분급이 불량하였고, 내리는 니사질역으로 분급이 매우 불량하였다. 서식밀도는 저질조성과 상관없이 씨뿌림에 의하여 외리와 백미리에서 높았으며, 내리와 종현동에서 낮게 나타났다. 비만도는 저질조성에서 분급이 매우 불량한 내리와 분급은 양호하지만 먹이생물인 클로로 필-a가 높았던 외리에서 높게 나타났다. 조사기간 동안 수온은 <TEX>$3.2-27.0^{\circ}C$</TEX> 범위로 나타났으며, 염분은 21.7-33.3 %, 용존산소는 5.6-12.7 mg/l, pH는 7.36-8.82였다. 부유물질은 3.2-1,266.0 mg/l, 클로로필-a는 <TEX>$0.3-36.1{\mu}g/l$</TEX>로 나타났다. 각 조사지역의 연간 바지락 비만도 및 성장은 해수중의 클로로필 농도와 유관한 것으로 사료되며, 이는 바지락의 먹이와 관련이 잇는 것으로 사료되었다.
From January to December 2007, we have investigated sediment types, environmental factors and density of clam Ruditapes philippinarum inhabited at Oeri, Naeri, Jonghyeon and Bangmiri tidal flats in Gyeonggi Bay off the west coast of Korea. Sediment types of Oeri and Jonghyeon were characterized with well sorted muddy sand. In contrast, Bangmiri tidal flat was mainly composed of poorly sorted gravelly muddy silt and Naeri was characterized with very poorly sorted muddy-sandy gravel. During the course of study, the surface water temperature, salinity, dissolved oxygen and pH ranged 3.2 to <TEX>$27.0^{\circ}C$</TEX>, 21.7 to 33.3 ‰, 5.6 to 12.7 mg/l and 7.36 to 8.82, respectively. The suspended solid (SS) ranged from 3.2 to 1,266.0 mg/l and chlorophyll-a level in the water column ranged <TEX>$0.3-36.1{\mu}g/l$</TEX>, respectively. The density of clam in the study areas was mainly determined by the harvesting activities rather than the types of substrate. Relatively higher density of clam was observed in Oeri and Bangmiri where the clam seeds were sowed by the villagers. Condition factor of clams were found to be higher in Oeri where the substrate sorting was better with higher level of chlorophyll a. It was believed that sediment types and the level of available food the two governing factors controlling the density and growth of clam in Gyeonggi Bay.
Many freshwater snail taxa are difficult to identify using morphological traits due to phenotypic plasticity. However, using of molecular DNA marker in combination with morphological traits can provide a reliable means for discriminating among freshwater snail taxa including cryptic species. To discriminate among Korean freshwater snail taxa and resolve their systematic relationships, wesequenced a fragment of mtDNA cytochrome oxidase I (COI) gene from 82 specimens collected from ten different sites distributed along the Korean peninsula. We identified more than seven freshwater snail taxa including cryptic species in Korea. Whereas traditional shell morphology of freshwater snails offers only weak discriminatory power for recognizing 'good' taxa, DNA sequence data provided positive and reliable identification. In addition, a major Semisulcospira clade was clearly separated from the remaining lineages observed including cryptic species. However, a phylogenetic tree inferred from the COI gene data did not fully resolve systematic relationships among pleurocerid taxa in Korea. Establishing more robust shell characteristics for identifying taxa unambiguously and hence improving traditional key shell morphology characters for freshwater snail species is an urgent requirement and will require more rigorous examination of all nominal taxa. While molecular data generated here will be useful for species identification and for describing the systematic relationships among Korean freshwater snails, further analysis will be required.
본 연구는 우리나라 무안, 태안, 여수, 제주 지역 및 중국 영성, 대련 지역의 낙지 개체군의 종 및 집단분석을 위해 미토콘드리아 CO1유전자의 염기서열을 조사하였다. 유전자 분석은 총 60 개체로부터 6개의 haplotype이 조사되었다. 제주 개체군인 경우 모든 개체 (N = 10) 가 다른 집단에서는 관찰되지 않은 A haplotype으로 구성되어 있어 다른 지역과 뚜렷한 차이를 나타내었다. 이들 haplotype은 MEGA 4 분석에 의해 두 개의 clade로 나뉘어지는데 하나는 무안, 태안, 여수, 중국 대련집단이었고 다른 하나는 제주, 중국 영성집단으로 나뉘는 구조를 하고 있었다. 집단 간 유연관계 분석에서도 같은 현상이 관찰되었다. Group A에 속하는 무안, 태안, 여수, 대련 집단의 낙지 개체군은 group B (제주, 영성) 에 속하는 집단 개체군 보다 유전적 거리가 아주 가까웠다. 본 연구에서 사용한 CO1 universal primer는 종 판별 유전자 마커로서 낙지류에서도 유용하게 활용될 수 있었으나 partial CO1 유전자 내의 변이가 많지 않기 때문에 집단분석에는 한계가 있으나, 지역적 거리 및 장벽 그리고 서식지 차이 등에서 오는 제한적 gene flow에 대한 논의는 가능할 것으로 판단된다.
The nucleotide sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene of octopus groups collected from Muan, Taean, Yesu, Jeju in Korea and Youngsung, Daeryen in China were analyzed for the identification of species and populations. Six haplotypes were identified from the analyzed 60 individuals. All of the individuals (N = 10) from Jeju showed the A haplotype which was not observed from other groups, and could be classified as a distinct group. The analyzed groups could form two separate clade in MEGA4 analysis. The individuals from Muan, Taean, Yesu in Korea and Daeryen in China form a clase and the others from Jeju in Korea and Youngsung in China formed the other clade. The analysis of relationship among the groups showed the same results. Individuals belong to the group A (Muan, Taean, Yesu and Daeryen) showed closer relationship than individuals belong to the group B (Jeju and Youngsung). Although the CO1 universal primers used in this study was useful as a marker for species identification among Octopus, analysis of population was limited because of few variations in the partial sequences of CO1 analyzed in this study. However, it was possible to show the limited gene flow among the groups which is resulted from the spatial separation and differences in their habitats.
본 연구에서는 제주도산 소라의 자원생태학적 특성치인 생잔율, 순간자연사망계수 및 순간어획사망계수, 어획개시연령을 추정하였으며, 직접 조사를 통한 자원량을 확인하였다. 생태학적 특성치 추정을 위한 표본은 2009년 9월부터 2010년 5월까지의 자료를 활용하였다. 순간전사망계수는 2.2062 /year로 추정되었으며, 순간자연사망계수는 0.8743/year로 추정되었다. 어구가입연령은 2.636 세로 추정되었다. 소라 자원을 가입당어획량 모델에 적용시킨 결과, 현재의 순간어획사망계수, 어획개시연령에서의 가입당생산량은 7.92 g으로 추정되었다. 따라서 현재의 순간어획사망계수를 그대로 유지한다면 어획개시연령을 2세에 맞추어야 하고, 현재의 어획개시연령을 유지한다면 순간어획사망계수를 0.2보다 낮은 수준으로 낮추어야 한다. <TEX>$F_{0.1}$</TEX>의 경우, 1세에서 2.58 g으로 가장 높은 가입당생산량을 나타내고 있다. 또한 가입당산란자원량 모델을 이용하여 생물학적 관리기준인 <TEX>$F_{40%}$</TEX>의 값을 현재의 어획상태를 고려하여 추정하였다. <TEX>$F_{max}$</TEX>, <TEX>$F_{0.1}$</TEX>, <TEX>$F_{35%}$</TEX>, 및 <TEX>$F_{40%}$</TEX> 에서의 가입당생산량은 10.44 g, 1.87 g, 6.53 g and 7.46 g으로 추정되었다.
Samples of Turbo (Batillus) cornutus Lightfoot, 1786 in Jeju Island were collected from September 2009 to May 2010. Population ecological parameters and stock assessment of the turban shell were determined, based on the length and age composition data from 2000 to 2009 and ecological parameters. Instantaneous coefficient of total mortality (Z) of turban shell was estimated to be 2.2062/year. The estimated instantaneous coefficient of natural mortality (M) was 0.874/year. The age of turban shell at its first capture (<TEX>$t_c$</TEX>) was 2.636 year. Yield-per-recruit were estimated under harvest strategies that based on <TEX>$F_{max}$</TEX>, <TEX>$F_{0.1}$</TEX>, <TEX>$F_{35%}$</TEX>, and <TEX>$F_{40%}$</TEX> was 10.44 g, 1.87 g, 6.53 g and 7.46 g.
개량조개의 종묘생산을 위한 생물학적 기초자료를 얻고자 난발생에 영향을 미치는 수온, 염분 및 수용밀도에 관하여 실험한 결과, 수온에 따른 난발생의 각 단계에 이르기까지의 수온 (TW, <TEX>$^{\circ}C$</TEX>)에 따른 발생속도 (h, 시간)는 <TEX>$18^{\circ}C$</TEX>, <TEX>$23^{\circ}C$</TEX>, <TEX>$28^{\circ}C$</TEX> 및 <TEX>$33^{\circ}C$</TEX>에서 D형 유생까지 각각 33시간 30분, 20시간 40분, 18시간 15분 및 15시간이 소요되어 수온이 높을수록 빨랐으며, 그 관계식은 다음과 같다. 2세포기 : 1/h = 0.1051WT - 1.4782 (<TEX>$r^2=0.9926$</TEX>) 8세포기 : 1/h = 0.037WT - 0.3686 (<TEX>$r^2=0.9648$</TEX>) 낭배기 : 1/h = 0.008WT - 0.0521 (<TEX>$r^2=0.9134$</TEX>) 담륜자 : 1/h = 0.0041WT - 0.0235 (<TEX>$r^2=0.9072$</TEX>) D형유생 : 1/h = 0.0024WT - 0.0102 (<TEX>$r^2=0.9611$</TEX>) 개량조개의 수온과 난발생 속도와의 관계에서 추정된 난발생의 생물학적 영도는 평균 <TEX>$8.0^{\circ}C$</TEX>였으며, 개량조개 수정란은 D형 유생까지의 발생률을 고려할 때 발생 가능한 수온은 <TEX>$18-28^{\circ}C$</TEX>, 적정 수온은 <TEX>$23^{\circ}C$</TEX>였다. 개량조개의 수정란이 D형 유생으로 발생 가능한 염분은 20-35 psu로 나타났고, 염분에 따른 수정란의 D형 유생까지 발생률을 고려할 때 최소 25 psu 이상이며 적정 염분은 30-35 psu였다. 수정란으로부터 D형 유생까지의 발생률을 높일 수 있는 수정란의 수용밀도는 사육수 1 ml 당 40개 이하로 나타났다.
Water temperature, salinity and density on egg development of the sunray surf clam, Mactra chinensis were investigated for artificial seedling production. The required time from fertilization to D-shaped larvae were 33.8 hours in <TEX>$18^{\circ}C$</TEX>, 20.6 hours in <TEX>$23^{\circ}C$</TEX>, 18.2 hours in <TEX>$28^{\circ}C$</TEX> and 15.0 hours in <TEX>$33^{\circ}C$</TEX>. The development duration was reduced with increasing temperature. The relationships between temperature and the required time from egg to each developmental stage were described as follows: 2-cell, 1/h = 0.1051WT - 1.4782; 8-cell, 1/h = 0.037WT - 0.3686; gastrula, 1/h = 0.008WT - 0.0521; trochophore, 1/h = 0.0041WT - 0.0235; D-shaped larva, 1/h = 0.0024WT - 0.0102. Biological minimum temperature for the egg development was estimated to be <TEX>$8.0^{\circ}C$</TEX> in average. The possible range of temperature for the development of D-shaped larvae was <TEX>$18-28^{\circ}C$</TEX> and optimum of water temperature for the development of egg was <TEX>$23^{\circ}C$</TEX>. The possible range of salinity for the development of D-shaped larvae was 20-35 psu and optimum of salinity for the development of egg was 30-35 psu over 25 psu at least. The density of fertilized egg was below 40 per 1 ml in rearing seawater for elevating the development rate from fertilized egg to D-shaped larva.
개량조개의 인공종묘생산을 위한 유생사육의 최적 사육환경과 먹이생물의 종류에 따른 유생의 성장 및 생존을 조사하였다. 수온에 따른 유생의 성장은 <TEX>$18^{\circ}C$</TEX>에서 <TEX>$33^{\circ}C$</TEX>까지 수온이 높을수록 빨랐으며, <TEX>$23^{\circ}C$</TEX> 이상에서는 사육 14일째 <TEX>$230{\mu}m$</TEX> 이상 성장하였으나 <TEX>$18^{\circ}C$</TEX>에서는 <TEX>$151.1{\mu}m$</TEX>로 성장이 부진하였다. 염분별 유생사육 시 염분 30 psu에서 일간 성장은 <TEX>$11.3{\mu}m$</TEX>로 가장 빨랐고, 생존율도 65.8%로 가장 높았다. 개량조개 유생은 사육수 1 ml 당 10개체 이하의 밀도에서는 성장과 생존율이 양호하였으나 20개체 이상에서는 다소 성장이 늦어 유생의 사육밀도는 1 ml 당 10개체 이하가 가장 효과적이었다. 개량조개 유생의 빠른 성장과 생존율을 높일 수 있는 유생사육 최적 조건은 수온 <TEX>$23^{\circ}C$</TEX>, 염분 30-35 psu, 유생 수용밀도 1-10 개체/ml이었다. 유생사육 시 먹이생물은 미세조류 4종 [Isochrysis galbana, Pavlova lutheri, Isochrysis sp. (green), Chlorella ellipsoidea] 을 혼합 공급한 실험구에서 빠른 성장과 생존율을 높일 수 있으며, 먹이생물을 단일종만을 공급시 I. galbana와 Isochrysis sp. (green) 실험구에서 빠른 성장과 생존율을 높일 수 있었다. 따라서 개량조개 유생의 적정먹이는 I. galbana와 Isochrysis sp. (green)를 포함한 2종 이상을 혼합 공급하는 것이 적합할 것으로 판단된다.
Rearing condition and species of microalgae on growth and survival of the sunray surf clam, Mactra chinensis larvae were investigated for artificial seedling production. The larvae of M. chinensis on higher temperature showed high growth and low survival and was grown over <TEX>$230{\mu}m$</TEX> in shell length 14 days after hatching, but low growth as <TEX>$151.1{\mu}m$</TEX> at <TEX>$18^{\circ}C$</TEX>. The larvae of M. chinensis on salinity showed highest daily growth and survival as <TEX>$11.3{\mu}m$</TEX> and 65.8% at 30 psu, respectively. The optimum of water temperature and salinity for the larval rearing were <TEX>$23^{\circ}C$</TEX> and 30-35 psu over 25 psu at least. The density of larval rearing was below 10 per 1 ml in rearing seawater for elevating the development rate from D-shaped to settled (metamorphosing) stage. The larvae fed the mixed diet of Isochrysis galbana, Pavlova lutheri, Isochrysis sp. (green), Chlorella ellipsoidea showed highest growth and survival. The larvae fed the single diet of I. galbana, Isochrysis sp. (green) showed high growth and survival. But the larvae fed the single diet of P. lutheri and C. ellipsoidea showed low growth and survival. The optimum diet of larvae of M. chinensis was over two species of microalgae included I. galbana, Isochrysis sp. (green) for elevating the high growth and survival.
Spermatid differentiations during spermiogenesis and mature sperm ultrastructure in male Crassostrea nipponica were investigated by transmission electron microscope observations. The morphology of the spermatozoon of this species has a primitive type and is similar to those of other bivalves. Mature spermatozoa consist of broad, cap-shaped acrosomal vesicle and an axial rod in subacrosomal materials on an oval nucleus showing deeply invaginated anteriorly, two triplet substructure centrioles surrounded by four spherical mitochondria, and satelite fibres, which appear near the distal centriole. The acrosomal vesicle of spermatozoa of C. nipponica resemble to those of other investigated ostreids. Especially, two transverse bands (stripes) appear at the anterior region of the acrosomal vesicle, unlikely 2-3 transverse bands (stripes) in C. gigas. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm morphology in the resolution of taxonomic relationships within the Ostreidea. The sperm is approximately <TEX>$48-50{\mu}m$</TEX> in length including an oval sperm nucleus (about <TEX>$1.0{\mu}m$</TEX> in length and <TEX>$1.41{\mu}m$</TEX> in width), an acrosome (about <TEX>$0.48{\mu}m$</TEX> in length and 0.30 in width) and tail flagellum (<TEX>$46-48{\mu}m$</TEX>). The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9 + 2 structure. These morphological charateristics of acrosomal vesicle belong to the family Ostreidae in the subclass Pteriomorphia.
The availability of fast and inexpensive sequencing technology has enabled researchers around the world to conduct many genome sequencing and expressed sequence tag (EST) projects of diverse organisms. In recent years, whole genome projects have been undertaken to sequence ten species from the phylum Mollusca. These include Aplysia californica, Lottia gigantea, Crassostrea virginica, Spisula solidissima, Mytilus californianus, Biomphalaria glabrata, Crepidula fornicata, Elysia chlorotica, Lottia scutum and Radix balthica. Additionally, complete mitochondrial genomes of 91 mollusks have been reported. In Korea, EST projects have been conducted in nine mollusk species that include Nesiohelix samarangae, Pisidium (Neopisidium) coreanum, Physa acuta, Incilaria fruhstorferi, Meretrix lusoria, Ruditapes philippinarum, Nordotis gigantea, Crassostrea gigas and Laternula elliptica. Finally, the mitochondrial genome projects from the Pacific Oyster (Crassostrea gigas) and the rock shell (Thais clavigera) have been conducted and reported. However, no systemic mollusk genome project has so far been conducted in Korea. In this report, the current status and research trends in mollusk genome study in Korea will be discussed.
