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ISSN : 1225-3480
The development of Japanese geoduck, Panopea japonica, grown under culture conditions, has been examined through the morphological characteristics in fertilized egg, larvae and juvenile. Gametes were stripped from ripe broodstock and placed into two separate containers. Eggs were washed through a <TEX>$40{\mu}m$</TEX> sieve and fertilized with dilute sperm solution. Developing larvae were maintained at <TEX>$19{\pm}1^{\circ}C$</TEX>. Fertilized eggs with <TEX>$81.6{\mu}m$</TEX> diameter developed to trochophores within 14 h and to D-stage larvae (<TEX>$116{\mu}m$</TEX> shell length) within 27 h. Larvae were spontaneously settled at shell length of <TEX>$311{\mu}m$</TEX> after 20 days. The hatching from fertilized eggs and larval rearing were normally available in <TEX>$18.5-21.5^{\circ}C$</TEX>, and the growth was good in a cashmilon substrate, as well as sand. After rearing of day 108 from metamorphosis, the shell length of juvenile P. japonica reached 13 mm, and growth rate of shell length of the juvenile was <TEX>$117.5{\mu}m/d$</TEX>.
Early sexual maturation through temperature stimulation was induced in female and male of yezo scallop. Gonadosomatic index (GSI) in female showed <TEX>$9.12{\pm}2.9$</TEX> in January, <TEX>$14.89{\pm}2.9$</TEX> in February and <TEX>$21.3{\pm}1.4$</TEX> in March in experiment I. GSI in experiment I showed a significant increase (P < 0.05) and in experiments II and III were not show significant variations (P > 0.05). It also showed significant between the control and the experiments I, II, and III in February (P < 0.05) measurements. Experiment I has showed good results in sexual maturation and spawning when compared with other experiments II and III and the control. Histological observation showed that ovary condition was in a growing stage in all the experiments I, II, and III. In February, ovary condition through histological observation was a late mature stage in all the experiments I, II, and III except the control of a growing stage. GSI and gonad weight were <TEX>$4.4{\pm}0.88$</TEX> and 2.8 g, respectively in November whereas it was <TEX>$15.1{\pm}2.8$</TEX>, and 11.7 g, respectively in January and <TEX>$21.7{\pm}5.4$</TEX>, and 19.4 g, respectively in February after rearing at a water bath of <TEX>$12^{\circ}C$</TEX> depending on the condition of experiment I. It was possible early releasing of eggs and sperms of yezo scallop in February instead of the middle of April to the end of May being spawning period. Fertilized eggs have become a gastrula stage through a spiral cleavage and then become a trochophore larvae after 36 hours. After 10 days, D-shaped larvae have changed into an umbo stage larvae and attached to juveniles in the post larvae after 20-23 days.
Patinopecten yessoensis is known to be farmed only in the northern part of the East Sea today. In an attempt to extend its production area, we have conducted experiments both in the northern and southern parts of the East Sea and studied on their growth in an aim to use the results for increasing overall productivity of the species. Early juvenile scallops producted in February 2014 showed an average shell length of <TEX>$0.23{\pm}0.002$</TEX>. The high growth group showed an average shell length and shell height of <TEX>$4.11{\pm}0.08mm$</TEX> and <TEX>$4.28{\pm}0.09mm$</TEX>, respectively, in June while they were <TEX>$23.63{\pm}3.4mm$</TEX> and <TEX>$24.19{\pm}4.5mm$</TEX> in October. The low growth group showed an average shell length and shell height of <TEX>$2.23{\pm}0.7mm$</TEX> and <TEX>$1.99{\pm}0.9mm$</TEX>, respectively, in June while they were <TEX>$1.99{\pm}0.9mm$</TEX> and <TEX>$17.59{\pm}4.5mm$</TEX> in October. The daily growth rate of the high growth group was 0.037 mm/day and 0.027 mm/day for the low growth group. In August, we measured the shell length of Patinopecten yessoensis from Yangyang-gun, Gangneung-si, Yeongdeok-gun, and Pohang-si. Patinopecten yessoensis from Pohang-si showed the best growth performance with its shell length of <TEX>$26.90{\pm}3.6mm$</TEX>. Patinopecten yessoensis from Yeongdeok was the second largest with its shell length of <TEX>$23.56{\pm}3.4mm$</TEX>. We presume that optimal water temperature and phytoplankton abundance of the two regions have contributed to the good growth performance of the species.
Ultrastructural studies of oogenesis in oocytes, oocyte degeneration associated with the follicle cells in female Coecella chinensis were investigated for clams collected from Namhae, Geongsangnam-do, Korea. In this study, vitellogenesis during oogenesis in the oocytes occured by way of endogenous autosynthesis and exogenous heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. whereas the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes prior to the formation of the vitelline coat. It is assumed that the follicle cells were involved in the development of previtellogenic and early vitellogenic oocytes and appear to play an integral role in vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors, and also they were involved in oocyte degeneration by assimilating products originating from the degenerated oocytes, thus allowed the transfer of york precursors needed for vitellogenesis (through phagocytosis by phagolysosomes after spawning). Follicle cells presumably have a lysosomal system for breakdown products of oocyte degeneration. and for reabsorption of various phagosomes (phagolysosomes) in the cytoplasm for nutrient storage during the period of oocyte degeneration.
We determined the effects of neuroactive compounds known as synthetic larval settlement inducers on the settlement of the Pacific oyster C. gigas pediveliger on the larval collector. Six types of the inducers, serotonin (5-HT), <TEX>${\gamma}$</TEX>-amino butyric acid (GABA), L-3,4-dihydroxyphenylalanine (L-DOPA), norepinephrine, epinephrine and methyl bromide (MB) were tested. All the chemicals induced larval settlement, MB being the most effective with settlement rate of <TEX>$42.7{\pm}2.7%$</TEX>, followed by GABA (<TEX>$35.4{\pm}2.0%$</TEX>), 5-HT (<TEX>$29.1{\pm}2.2%$</TEX>), L-DOPA (<TEX>$19.2{\pm}2.1%$</TEX>), epinephrine (<TEX>$15.2{\pm}0.9%$</TEX>), and norepinephrine (<TEX>$11.0{\pm}1.2%$</TEX>). The chemicals <TEX>${\gamma}$</TEX>-amino butyric acid and methyl bromide were also better in terms of settled density on the collector with their respective density of <TEX>$1.97{\pm}1.42$</TEX> and <TEX>$2.37{\pm}1.86ind/cm^2$</TEX>, reminiscent of being most effective candidates for a larval settlement inducer in the oyster hatchery.
In order to investigate the effects of copper alloy on abalone physiology, we studied survival rate, respiration, excretion rate, and heavy metal accumulation in each organ of adults and spats. The survival rate of spats and adults showed 27-60% and 63-83% respectively, higher survival rate in adults. In particular, 100% of copper panel led to lowest survival rate and there was no sharp distinction according to copper alloy composition. The respiration rate and excretion rate of ammonia nitrogen was <TEX>$1.81mgO_2/g$</TEX> D.W./h and 0.43 mg <TEX>$NH_4-N/g$</TEX> D.W./h respectively at 100% of copper panel. In other words, there was a high significant difference at the level, but no significant difference at other test levels (P < 0.05). The atomic ratio (0: N) hit the lowest at the 100% of copper panel showing 3.79 and no significant differences were seen among other test groups with 6.57-7.18 of a very low range. This means that the species might have undergone nutritional stress. In case of copper accumulation, the 100% copper panel group showed the highest level in hepatopancreas and muscle showing 6.91 mg/kg and 1.60 mg/kg respectively but the rest of groups showed similar levels. Zinc accumulation raised at Cu-Zn alloy panel had high significance showing 18.50 mg/kg and 1.10 mg/kg in hepatopancreas and muscle respectively (P < 0.05). To sum up, a cage net made of 100% pure copper is expected to have a negative effect on abalone in light of survival rate, heavy metal accumulation, and atomic ratio (0: N). Moreover, given that the substratum used for the high adhesive species and nutritious stress that is represented through the atomic ratio need to be considered, the copper alloy net is thought not to be suitable for abalone aquaculture.
We investigated the survival rate by water temperature and salinity, physiological rhythm and morphological change of live abalone to get to know optimum water temperature and salinity suitable for long-distance transportation of live abalone. At <TEX>$8^{\circ}C$</TEX> and above, 96-100% of survival rate was shown at all experiment groups. At <TEX>$6^{\circ}C$</TEX>, 66% of abalones survived in normal seawater but they showed 0% of survival rate at <TEX>$30{\pm}0.5psu$</TEX> and <TEX>$26{\pm}0.5psu$</TEX> of salinity at the same water temperature. There was no significant difference of oxygen consumption rate for a week between the seawater and <TEX>$30{\pm}0.5psu$</TEX>. Also, a positive correlation was shown between salinity and water temperature and the oxygen consumption rate was slightly higher at <TEX>$30{\pm}0.5psu$</TEX> than seawater. Thinned epithelial layers and expansion of lymph sinus were observed less than <TEX>$30{\pm}0.5psu$</TEX> or below <TEX>$6^{\circ}C$</TEX> of temperature. This result shows that the optimum level of water temperature and salinity is considered to be <TEX>$6-8^{\circ}C$</TEX> and more than <TEX>$30{\pm}0.5psu$</TEX> respectively.
The bioaccumulation of 16 United States Environmental Protection Agency (USEPA) priority polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the Manila clam, Ruditapes philippinarum exposed to sediments artificially contaminated by Iranian Heavy Crude Oil was measured and the biota-sediment accumulation factor (BSAF) was estimated through laboratory experiments. The proportion of 16 PAHs accumulated in the tissue of R. philippinarum was only from 3 to 7% of total PAHs. Among 16 PAHs, the concentration of naphthalene was highest in the tissue. Alkylated PAHs were highly accumulated more than 93% of total PAHs. The C3 dibenzothiophene was most highly accumulated. The relative composition of alkylated naphthalenes in the tissue of R. philippinarum was lower than in the sediments. In contrast, those of alkylated compounds of fluorenes, phenanthrenes, dibenzothiophenes were higher in the tissue than the sediments. The BSAF for sum of 16 PAHs was 0.11 to 0.13 g carbon/g lipid and that for alkylated PAHs was 0.05 to 0.06 g carbon/g lipid. Naphthalene showed the highest BSAF value. Alkylated PAHs with the same parent compound, BSAF tended to increase with the number of alkylated branch increased, except for alkylated chrysenes. BSAF of total PAHs lies between that of field-based values, and are also similar to those of other persistent organic pollutants (PCBs, DDTs, HCHs). This study provides the BSAF values of individual alkylated PAHs accumulated in R. philippinarum for the first time and will be used as a basis for further understanding the bioaccumulation of organic contaminants in the marine benthic organisms.
The multiplex PCR system including six microsatellites from Haliotis discus hannai, consisting of dinucleotide and trinucleotide repeat units, is developed. The six loci were coamplified in a single reaction employing dye-labeled primers. Alleles from these loci were sized using an internal standard by automated sample processing in an ABI3100 Genetic Analyser. Amplified alleles in profiles containing selected microsatellites were typed clearly, providing easily interpretable results. In this results suggest that the presented multiplex PCR system may be a useful tool in a selective breeding program of H. discus hannai in which genetic identification will allow different genotypes to be reared together from fertilization. This should have a great impact as it will make selective breeding more efficient. Moreover, it will be useful in a variety of applications, including strain and hybrid identification, parentage assignment, pedigree reconstruction, estimating genetic diversity and/or inbreeding.
Previously, we have reported expressed sequence tags (ESTs) analysis on the land snail, Nesiohelix samarangae (Ns). Of these ESTs, we have identified four partial fragments of N. samarangae cytochrome oxydase I (NsCO-I) gene which lead to obtain an 852 bp partial cDNA. Since NsCO-I is one of the best-known molecular phylogenetic markers, we have attempted to conduct comparative in silico analysis by using the NsCO-I gene. The combined results from BLAST analyses, multiple sequence alignment and molecular phylogenetic study of NsCO-I cDNA indicate that N. samarangae has similarity to three land snails such as Elona quimperiana, Euhadra herklotsi and Euhadra idzumonis.
Glutathione S-transferases (GSTs) are a superfamily of detoxification enzymes that primarily catalyze the nucleophilic addition of reduced glutathione to both endogenous and exogenous electrophiles. In this study, we isolated and characterized a full-length of alpha class GST cDNA from the abalone (Haliotis discus hannai). The abalone GST cDNA encodes a 223-amino acid polypeptide with a calculated molecular mass of 25.8 kDa and isoelectric point of 5.69. Multiple alignments and phylogenetic analysis with the deduced abalone GST protein revealed that it belongs to the alpha class GSTs and showed strong homology with disk abalone (Haliotis discus discus) putative alpha class GST. Abalone GST mRNA was ubiquitously detected in all tested tissues. GST mRNA expression was comparatively high in the mantle, gill, liver, and digestive duct, however, lowest in the hemocytes. Expression level of abalone GST mRNA in the mantle, gill, liver, and digestive duct was 182.7-fold, 114.8-fold, 4675.8-fold, 406.1-fold higher than in the hemocytes, respectively. Expression level of abalone GST mRNA in the liver was peaked at 6 h post-infection with Vibrio parahemolyticus and decreased at 12 h post-infection. While the expression level of abalone GST mRNA in the hemocytes was drastically increased at 3 h post-infection with Vibrio parahemolyticus. These results suggest that abalone GST is conserved through evolution and may play roles similar to its mammalian counterparts.
Purple-colored shell individuals were discovered among normal green-colored shell individuals in artificial seed of Pacific abalone, Haliotis discus hannai, reared on an ordinary type of diatom and artificial diet. In the present study, factorial mating experiments were designed to clarify the genetic control of the variant (purple type) and normal (green type) of shell color. The parental population of purple type and green type individuals were derived from a single family between a female and male of each type of coloration. The all mating families were reared in same tank for the same breed environment. The individual of 4 type families were distinguished by paternity test using microsatellite DNA. In factorial mating experiments, all individuals offspring of GG (green type female and green type male), GP (green type female and purple type male) and PG (purple type female and green type male) mating types appeared to green type. In only PP (purple type female and purple type male) mating type, all individuals offspring appeared to purple type. The results suggested that the purple shell color is controlled by recessive purple type allele and a dominant green type allele at a single locus.
Inbreeding depression may be an avoidable phenomenon for abalone culture. However, only a few studies were carried out on inbreeding depression. In the present study, to demonstrate inbreeding depression in growth trait of Pacific abalone, H. discus hannai, inbreeding and outbreeding families were produced in 2010. Inbred and outbred families from each experiment were reared in same tank until 10 month for the same breed environment. The individual of inbred and outbred were distinguished by paternity test using microsatellite DNA. The shell length between inbred and outbred families was compared. At the results, significantly higher shell length was observed in the outbred families at 10 mon (P < 0.05). These results indicate that inbreeding depression is obviously observed in growth traits in the first generation of full-sib family of the H. discus hannai.
Total 20 surface sediments were collected in Anjung bay to investigate the physicochemical environment and heavy metal contents. The physicochemical investigation ranged from 6.41% to 11.68% (average <TEX>$9.52{\pm}1.28%$</TEX>) for ignition loss (IL), from 17.99 mg/g to 43.84 mg/g (average <TEX>$27.53{\pm}6.39mg/g$</TEX>) for chemical oxygen demand (COD), and from 0.05 mg/g to 0.61 mg/g (average <TEX>$0.17{\pm}0.14mg/g$</TEX>) for acid volatile sulfide (AVS) with significant correlation between water content (W/C) and COD. A contour of spatial distribution indicated higher organic pollution at the bottom of ascidian, Stylea clava, cultural waters. Most of metals contents was not exceeded the NOAA's effect range-low (ERL). Estimated enrichment factor (EF) ranging 0.96-1.12 indicated that the sediment environment of the studied waters was relatively pristine from heavy metal pollution in spite of increased vessel traffics, so far.
Since we reported a BLAST server for the mollusk in 2004, no work has reported the usability or modification of the server. To improve its usability, the BLAST server for the mollusk has been updated as version II (http://www.malacol.or.kr/blast) in the present study. The database was constructed by using the Intel server Platform ZSS130 dual Xeon 3.20 GHz CPU and Linux CentOS system and with NCBI WebBLAST package. We downloaded the mollusk nucleotide, amino acid, EST, GSS and mitochondrial genome sequences which can be opened through NCBI web BLAST and used them to build up the database. The updated database consists of 520,977 nucleotide sequences, 229,857 amino acid sequences, 586,498 EST sequences, 23,112 GSS and 565 mitochondrial genome sequences. Total database size is 1.2 GB. Furthermore, we have added repeat sequences, Escherichia coli sequences and vector sequences to facilitate data validation. The newly updated BLAST server for the mollusk will be useful for many malacological researchers as it will save time to identify and study various molluscan genes.
A chromodorid nudibranch species Cadlinella subornatissima Baba, 1996 (Gastropoda: Nudibranchia: Chromodorididae) is newly recorded from Korean water. In this report, detailed external morphology is provided with its colored illustrations. This species is morphologically distinguished from other congeneric species by the following characteristics: the tip of dorsal papillae is pointed with pink pigment; yellow dorsal marking on central dorsum without mantle margin. The Korean chromodorid nudibranchs are composed of 19 species of 10 genera, including Cadlinella subornatissima which is firstly reported in the present study.
One specimen of Argonauta argo belonging to the family Argonautidae, was collected Songjeong, southeastern coastal water of Korea on July 12, 2010. The specimen, a mature female of 76 mm mantle length and 97 mm shell length. The number of ribs are 56 in shell. The shell is distinct between the arm I's. The I arm has expanded, hemi-discoidal web to which the distal part is fused together. The funnel is large and exceeds the base of arm IV. The arms formula is IV > <TEX>$II{\fallingdotseq}III$</TEX> > I. The specimen was female. Fecundity was 155,203 eggs. This species is pelagic octopus and important prey item of dolphin.
Triploids have several potential advantages over diploids in aquaculture, drawing an elevated commercial reaction into the realistic application of the techniques despite we are still in the early stage of triploid industry for the Pacific oysters Crassostrea gigas. We traced the growth performance of the triploid C. gigas for over a year from hatchery spats, which was created by manipulations of chemicals (Cytochalasin B, CB or 6-Dimethylaminopurine, 6-DMAP). The growth was clearly marked by an initial longer dormancy and following a great magnitude of heterogeneity. The dormancy was almost 9 to 10-month long or even longer and was considered as a downside of the creation. The heterogeneity was magnified by appearance of extraordinarily growing oysters in part during summer season, which could be a representative upside of the triploids. Overall, however, the results were not as positive as were expected. The longer dormancy and following heterogeneity observed in our practice could be marked as an additional negative sign of the chemical use. The present study, thus, might be highly indicative in the introduction of biological cross between tetraploid and diploid to produce natural triploid embryos.
