A specimen of the unknown form of Octopus species was collected from Onsan, Kyungsangnam-do, eastern coast of Korea on 20th June 2004 with a bottom trawl. The specimen distinguished from the other Octopus species reported hitherto by its extremely short 2nd pair of arm and hectocotilization of the right 4th arm. It may be described, therefore, as new species, but only one specimen was collected unfortunately. A new name will be deferred, consequently, until more specimens will be available in the future.
Genomic DNA isolated from two geographical ark shell (Scapharca subcrenata) populations was amplified several times by PCR reactions. The ark shell population from Daecheon (ASPD) and from Wonsan (ASPW) in the West Sea and the East Sea of Korean Peninsula, respectively, obtained. The seven arbitrarily selected primers OPA-05, OPA-11, OPB-09, OPB-11, OPB-14, OPC-18 and OPD-07 were shown to generate the loci observed per primer, shared loci by each population, specific loci, unique shared loci to each population and shared loci by the two populations which could be clearly scored. Here, 862 loci were identified in the ASPD population, and 1,191 in the ASPW population: 137 specific loci (15.9%) in the Daecheon population and 84 (7.1%) in the Wonsan population. 407 shared loci by each population, with an average of 58.1 per primer, were observed in the ASPD population. 473 shared loci by each population, with an average of 67.6 per primer, were identified in the ASPW population. The numbers of specific loci in the ASPD and ASPW population were 137 and 84, respectively. Consequently, the average bandsharing value of individuals within the ASPW population was much higher than in the ASPD population. The bandsharing value between individuals’ no. 08 and no. 13 was 0.628, which was the highest measured between the two geographical populations. The dendrogram obtained by the seven primers indicated three genetic clusters: cluster 1 (DAECHEON 01 ~ DAECHEON 11), cluster 2 (WONSAN 12 and 14) and cluster 3 (WONSAN 13, 15, 16, 17, 18, 19, 20, 21 and 22). The genetic distance between the two geographical populations ranged from 0.043 to 0.499. Especially, individual no. 10 of Daecheon population was most distantly related to no. 14 of Wonsan population (genetic distance = 0. 499).
Because it is known that bivalve hearts contain various modulatory systems activated by neuroendocrine substances, it was examined whether different classes of endogenous and synthetic drugs of neuroendocrinological importance can influence cardiac functions of the Pacific oyster Crassostrea gigas. Cholinergically active agents acetylcholine and carbachol increased heart rates while diminishing cardiac contractility. Adrenergically active substances norepinephrine (NE) and epinephrine (Epi) also induced heart rate increase and contractility decrease. An α1-adrenergic receptor-selective agonist phenyephrine (PE) failed to modulate either parameter. The Epi-induced heart rate increase and contractile depression were both blocked significantly by non-selective β1/β2-adrenergic antagonist propranolol. A β1-selective antagonist atenolol prevented Epi-induced heart rate decrease but not the contractile depression, suggesting possible β2 receptors for Epi-induced contractile depression. The three autacoids examined exerted discrete responses: histamine increased heart rate and depressed contraction; γ-amino-butyric acid increased both parameters; serotonin failed to change either parameter. The 5 piscine anesthetic agents examined, MS-222, benzocaine, quinaldine, urethane, pantocaine and pentobarbital, all failed to influence the cardiac function of oysters. Collectively, activities of neuroendocrinologically acting agents in mammals showed unexpected and distinct activities from those accepted based on mammalian cardiovascular systems. These results obtained from substances of different physiological can serve as a basis for understanding neuroendocrine control of the heart function in Pacific oyster.
2006년 6월부터 11월까지 매월 1회씩 제주도 귀덕, 신산, 김녕, 강정 연안에서 정치망에 의해 채집된 창꼴뚜기를 대상으로 창꼴뚜기의 생식생물학적 특성에 관하여 연구하였다. 조사기간 동안 총 759 개체의 창꼴뚜기 중에서 암컷은 429 개체, 수컷은 330 개체로 나타났다. 암컷의 경우, 조사 기간 중 미숙, 중숙, 성숙, 완숙기의 개체들이 혼재하여 출현하였으며 산란이 가능한 완숙 개체는 조사기간 중 초기인 6월을 제외하고 모든기간에 걸쳐 관찰되었고, 11월에 출현비율이 가장 높았다. 수컷도 조사기간 중 미숙, 중숙, 성숙, 완숙기의 개체들이 혼재하여 출현하됐으며 생식소의 숙도가 방정이 가능한 성숙단계이상의 개체는 전 기간에 걸쳐 관찰되었고 완숙기의 개체는 암컷과 같이 11월에 출현비율이 가장 높았다. 창꼴뚜기가 산란에 참여하는 군성숙외투장을 알아본 결과 성숙외투장은 17.1cm 로 추정되었다.
Samplings have been monthly collected in Jeju Island, Korea, using ser nets. A total of 759 individuals were sampled from June to November 2006. We analyzed mantle length distrbution, monthly changes in maturity stages, maturation size and sex ratio. Mean Mantle length of the female specimens ranged from 6.7 to 50.3 cm and that of the male specimens ranged from 6.7 and 50.0 cm. The spawning period was November. The Mantle length at 50 % group maturity was estimated to be 17.1 cm. Sex ratio was 1 : 1.3 (male : female), suggesting the female population may be predominant.
This study devised and tested a histological staging system for gonadal development in the trumpet snail, Charonia sauliae, which was collected along the south coast of Jeju Island, South Korea. This paper details for the first time the gonadal development characteristics of C. sauliae. Ovary and testis development in C. sauliae can be roughly divided into five stages: growing, mature, spent, degenerative, and resting. The trumpet snail has multiple fecundation and fertilization [cycles?] during the spawning season for out-of-step gonadal development in high-temperature and low-salinity environments. Female trumpet snails tended to have larger shells and were more abundant than males (64.26% of all animals collected were female).
The trumpet shell Charonia sauliae is an endangered and valuable species with potential for aquaculture. For artificial propagation of C. sauliae, the effects of three different food microalgae on the development, growth, and survival rate of the larvae and spat were investigated. For the larval feeding experiments, we utilized six microalgae species as food sources, namely Pavlova lutheri, Tetraselmis suecica, Nannochloris oculata, Isochrysis galbana, Chaetoceros calcitrans, and Phaeodactylum tricornutum; for the larval and spat growth and survival experiments, we utilized T. suecica, C. calcitrans, and P. tricornutum. The results showed that the temporal digestion index (TDI) for the veliger larvae was significantly different for C. sauliae fed the different microalgae species (P < 0.05), that the T. suecica, C. calcitrans, and P. tricornutum cultivars were better suited for larval consumption (P < 0.05), and that the growth and survival of the larvae and spat were significantly influenced by food type, specifically P. tricornutum (P < 0.05). Further research is needed to evaluate the effects of other microalgae species, different algal concentrations, and biochemical composition on the growth and survival of C. sauliae.
Random amplified polymorphic DNA (RAPD) marker and sequence analyses of the internal transcribed spacer (ITS) region of ribosomal DNA were used to assess phylogenetic relationships of four Korean oyster species. The average number of species-specific markers identified from five universal rice primers (URPs) by RAPD-PCR was 1.8 for Crassostrea gigas, 3.2 for C. nippona, 3.6 for C. ariakensis, and 4.6 for Ostrea denselamellosa. The length of the ITS (ITS1-5.8S-ITS2) region ranged from 1,001 to 1,206 bp (ITS1, 426-518 bp; 5.8S, 157 bp; and ITS2, 418-536 bp), while the GC content ranged from 55.5-61.1% (ITS1, 56.8-61.8%; 5.8S, 56-57.3%; and ITS2, 54.1-62.2%). A phylogenetic analysis of the oysters based on our RAPD, ITS1, and ITS2 sequence data revealed a close relationship between C. gigas and C. nippona and a distant relationship between the genera Crassostrea and Ostrea. Our results indicated that RAPD and ITS sequence analysis was a useful tool for the elucidation of phylogenetic relationships and for the selection of species-specific markers in Korean oysters.
Based on investigation of collections at the A.V.Zhirmunsky Institute of Marine Biology of the Far-Eastern Branch of the Russian Academy of Sciences (Vladivostok) and Zoological Institute of the Russian Academy of Sciences (Saint Petersburg), as well as on the analysis of published data, the species composition of shell-bearing gastropod mollusks of the Russian waters of the East Sea (Sea of Japan), consisting of 331 species and subspecies, has been identified. Each species is assigned to a biogeographic grouping in the study area. Its type locality and habitat (depth and substrate) are also documented. The third part of this review includes 129 species in Neogastropoda (Caenogastropoda)
Based on investigation of archive collections of A.V.Zhirmunsky Institute of Marine Biology of the Far-Eastern Branch of the Russian Academy of Sciences (Vladivostok) and O.A. Scarlato Zoological Institute of the Russian Academy of Sciences (Saint Petersburg), as well as on the analysis of published data, the species composition of shell-bearing gastropod mollusks of the Russian waters of the East Sea (Sea of Japan), consisting of 331 species and subspecies, has been identified. The fourth part of the Review includes 46 species of Heterobranchia (Allogastropoda, Opistobranchia, and Pulmonata). Each species is assigned to a biogeographic grouping in the study area. Its type locality and habitat (depth and substrate) are also documented.
본 연구에서 우리는 다양한 컬러의 담수양식진주(화이트, 오렌지, 퍼플 등)을 사용하여, 담수진주의 컬러를 변화시켜 가치향상을 목적으로 다양한 온도 및 시간별로 열처리를 실시하였다. 진주의 손상을 최대한 막고 컬러를 향상시킬 수 있는 최적의 조건(온도 및 시간)을 정립하여, 그에 따른 진주의 컬러변화, 광택, 성분분석, 내부구조 등의 변화를 UV-Vis, ED-XRF, SEM 등을 사용하여 비교 관찰하였다. 결론적으로 우리는 열처리를 통하여 담수양식진주의 컬러와 광택 및 상품가치를 높일 수 있는 가장 적합한 조건을 제시하고자 하였다.
In this study, we conducted heat-treatment on freshwater cultured pearls at various conditions in other to improve their color. Also, after heat treatment, we used the UV-Vis, ED-XRF and SEM to investigate changes freshwater cultured pearls’ color, composition and internal structure. UV-Vis analysis showed the reflectivity of samples increased at most heat-treatment conditions although the reflectivity decreased at a certain temperature and duration. At 100°c/8 h, 120°c/6 h and 140°c/4 h, the reflectivity increased highest. In proportion to reflectivity increase, freshwater cultured pearls’ color was improved. Ca, Mn, Sr and other micro elements were found from ED-XRF analysis. However, changes in composition of elements were not detected. It was found that the content of Mn in freshwater cultured pearl is higher than other micro elements. From SEM analysis, aragonite's shape was shown in narce and some of the narce were condensed after heat treatment.