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The importance of the temperature tolerance of fish is increasing due to climate change caused by global warming. This study examined the expression of the heat shock protein 70 (HSP70) gene, and plasma cortisol and glucose levels, as a stress response in red-spotted and hybrid groupers during exposure to heat and cold shock. Temperature in the tank where fishes acclimated at 20℃ was gradually increased or decreased, respectively, to examine the survival rate of fish. The result showed a higher survival rate of the hybrid than that of the red-spotted grouper upon exposure to a higher temperature. To further analyze the factors associated with temperature-associated stress, fishes were collected from different temperatures which changed from 20 to 30℃ or 10℃, respectively, and then back to 20℃. The expression levels of the gene encoding heat shock protein 70 (HSP70) were analyzed by qPCR using cDNA prepared from RNA extracted from the brain. A higher level of HSP70 transcript was detected in the hybrid during heat shock exposure. Analysis of cortisol and glucose from the blood of fish collected during the acclimation periods clearly indicated that the level of cortisol was increased upon temperature shift although a slight difference in the degrees of changes timing was slightly different between red-spotted grouper and hybrid. The results showed a correlation between the level of HSP70 and survival rate upon exposure to higher temperature shock. This study provides basic information regarding whether HSP70 expression increases the survival rate of fish subjected to rapid temperature changes. more...

Intermediate-term preservation of sperm assists the reproductive management of fish spermatozoa; however, no information is available on sperm of the spotted halibut, Verasper variegatus. We aimed to identify the optimum diluents, temperatures, dilution ratios, antibiotics, and antioxidants for sperm motility and cell viability. The diluents evaluated were marine fish Ringer’s solution (MFRS), Stein’s solution, 300 mM sucrose, and 300 mM glucose (diluted 1:1 [sperm: diluent], 1:2, 1:4, and 1:10 and stored at 0, 2, 4, and 6 °C). Neomycin and gentamycin (100, 200, 400, and 800 mg/L) and antioxidants (Mito-TEMPO [0, 25, 50, 75, 100, 125, 150, 175, and 200 µM], reduced glutathione [0, 2, 4, 6, 8, and 10 mM], and trehalose [0, 50, 100, 150, 200, and 250 mM]) were assessed in terms of sperm preservation. The most effective condition for cold storage of spotted halibut sperm was Stein’s solution at a dilution ratio of 1:4 at 2 °C, with a combination of neomycin 800 mg/L and 250 mM trehalose that showed spermatozoa motility of > 43% after 60 days. These storage conditions will be valuable for spotted halibut hatcheries. more...

Genes that influence the growth of Pacific abalone (Haliotis discus hannai) may improve the productivity of the aquaculture industry. Previous research demonstrated that the differential expression of a gene encoding a C-type lectin domain-containing protein (CTLD) was associated with a faster growth in Pacific abalone. We analyzed this gene and identified an open reading frame that consisted of 145 amino acids. The sequence showed a significant homology to other genes that encode CTLDs in the genus Haliotis. Expression profiling analysis at different developmental stages and from various tissues showed that the gene was first expressed at approximately 50 days after fertilization (shell length of 2.47 ± 0.13 mm). In adult Pacific abalone, the gene was strongly expressed in the epipodium, gill, and mantle. Recombinant Pacific abalone CTLD purified from Escherichia coli exhibited antimicrobial activity against several Gram-positive bacteria (Bacillus subtilis, Streptococcus iniae, and Lactococcus garvieae) and Gram-negative bacteria (Vibrio alginolyticus and Vibrio harveyi). We also performed bacterial agglutination assays in the presence of Ca2+, as well as bacterial binding assays in the presence of the detergent dodecyl maltoside. Incubation with E. coli and B. subtilis cells suggested that the CTLD stimulated Ca2+-dependent bacterial agglutination. Our results suggest that this novel Pacific abalone CTLD is important for the pathogen recognition in the gastropod host defense mechanism. more...

The aim of the present study is to develop an eco-friendly, simple, cost-effective and single-step method for the synthesis of gold nanoparticles using Agrimonia pilosa (AP-AuNPs) aerial parts extract and evaluation of their antioxidant and cytotoxic activity. Synthesis of AP-AuNPs was observed by a color change from light yellow to wine-red, and confirmed by the UV–VIS absorbance peak at 535 nm. From transmission electron microscopic analysis it is observed that the AP-AuNPs were hexagonal with size of about 20–50 nm. The field emission-scanning electron microscopy image revealed the synthesized AP-AuNPs to have a hexagonal shape. The energy-dispersive X-ray and X-ray diffraction analyses confirmed the metal gold and crystalline nature of AP-AuNPs. A. pilosa extract-mediated AP-AuNPs were found to be non-toxic on normal cells (HaCaT, Keratinocyte), exhibited a concentration-dependent cytotoxic effect on cancer cells (AGS, gastric adenocarcinoma) and antioxidant potential. The AP-AuNPs are synthesized using the A. pilosa aerial part extract using a simple and eco-friendly method. The synthesized AP-AuNPs can be useful in therapeutics. more...

dnd is a germline-specific maternal RNA expressed in various vertebrate classes, which encodes an RNA-binding protein that is essential for PGC migration. The purpose of this study is fundamental research about starry flounder dnd gene for germ cell marker development. In this study, we cloned and analyzed the expression levels of Platichthys stellatus dead end (psdnd) in various tissues and embryonic stages. The psdnd gene was isolated from starry flounder ovaries, cloned into a pGEM-t vector, and sequenced. Full-length of psdnd cDNA was 1495 bp long, encoding 395 amino acids. psdnd expression levels were investigated by real-time polymerase chain reaction (qRT-PCR) in various tissues and embryo developmental stages. psdnd transcripts were detected in the testes and ovaries, but not in somatic tissues. Embryonic psdnd expression levels were higher during early embryo development stages than during late embryogenesis, psdnd expression was highest at the 1 cell stage, then gradually decreased throughout the subsequent developmental stages. The spatial expression pattern was analyzed by whole-mount in situ hybridization (WISH). The psdnd transcripts migration pattern was similar with zebrafish (Danio rerio). Our results suggest that psdnd may function as a germ cell-specific marker. more...

The roughscale sole, Clidoderma asperrimum is categorized as an endangered species. Sperm freezing is essential for preserving gametes. This study examined the CPA concentration, diluent, dilution ratio, and thawing temperature to design a sperm cryopreservation protocol for roughscale sole. The variables examined included sperm motility and kinematics, cell survival, fertilization, and DNA fragmentation. Sperm motility parameters were assessed via computer-assisted sperm analysis using a CEROS II instrument. Cell survival rate and DNA damage were assessed using the Cell Counting Kit-8 and single-cell gel electrophoresis assay, respectively. Sperm preservation was tested using several CPAs, including ethylene glycol, dimethyl sulfoxide (DMSO), glycerol, propylene glycol, and methanol. The diluents tested were 300 mM sucrose, 300 mM glucose, Stein’s solution, Ringer’s solution, and Hank’s solution. The optimal conditions for sperm cryopreservation were 10% DMSO + Stein’s solution. After thawing, sperm motility was highest with a 1:1 dilution ratio (sperm to CPA + diluent), at 69.20 ± 0.32%; thawing at 10 °C was optimal for post-thaw motility (72.03 ± 0.95%). The highest fertilization rate (40.00 ± 1.22%) was obtained using DMSO. The fresh sperm had the lowest tail DNA, followed by 10% DMSO + Stein’s solution. The developed cryopreservation methods can be used in roughscale sole hatcheries. more...

Complete mitochondrial genomes of two Pleuronectid species, Clidoderma asperrimum and Verasper variegatus (Teleostei: Pleuronectiformes: Pleuronectidae) were analysed using the primer walking method. Their mitogenomes were 17,632 and 17,273 bp in total length, respectively and comprised 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes. Their gene contents and orders were similar to those of typical vertebrates. All Pleuronectid species were subdivided into three clades in the phylogenetic tree, and the two Pleuronectid species analysed in this study formed a strong monophyletic group comprising species belonging to three genera, Hippoglossus, Reinhardtius, and Verasper. more...

The fungus Chaetomium sp. is a causative agent of infections in humans and is ubiquitous in the natural environment. The secondary metabolites of this genus exhibit many biological activities, including antifungal activity and toxicity in mitochondria. In this study, we isolated cristazine from the fungus C. cristatum, which has the potential to inhibit the growth of human epidermoid carcinoma (A431) cells in a dose- and time-dependent manner. Its inhibitory activity was examined using a cell viability assay and cell death was elucidated by western blot analysis. Cristazine triggered apoptotic cell death via the Type I death receptor pathway including the activation of caspases and other target proteins. However, cristazine did not have any effect on mitochondrial apoptotic proteins such as Bid, cytochrome c, and apoptosis-inducing factor. Cristazine inhibited the cell cycle progression by arresting the G1 /S phase and up-regulating the inhibitory proteins of cyclin-dependent kinases. Thus, cristazine has great potential for inducing apoptosis in A431 cells via both cell cycle arrest and the inhibition of cell growth. more...

In this study, we identified four canonical calmodulin genes in the Pacific abalone, Haliotis discus hannai. Their full-length cDNAs were variable in the 5′ and 3′ untranslated regions, but highly similar (91–97%) in the coding region. Each of the genes encoded 149 amino acids, with 93–97% similarity among themselves and 94–98% similarity with human CAM I. There were 54 substitutions distributed unevenly throughout the coding regions, found mostly in the third codon position. Gene structure analysis revealed that each of the calmodulin genes comprised five exons and four introns. The intron positions and phases were identical and there were no introns in the fourth exon. The corresponding introns differed in their sequences and sizes. Expression profiles of nine tissues from abalone revealed that the calmodulin genes were transcribed in common in gill and mantle tissue, but differentially in the other tissues. A phylogenetic analysis based on the amino acid sequences revealed that calmodulin C was the most common isoform in Gastropoda and calmodulin was the most diverged isoform. An in silico analysis of the calmodulin genes identified paralogous genes in other Haliotis species, indicating that gene duplication might have occurred in the last common ancestor of Haliotis. Abbreviations: ORF: open reading frame; RACE: random amplification of cDNA end; TSA: transcriptome shotgun assembly; UTR: untranslated region more...

We investigated various factors, including cryoprotective agents (CPAs), diluents, and freezing rates, to develop an optimal cryopreservation protocol for Epinephelus akaara sperm. In experiments using 10% dimethyl sulfoxide (DMSO), glycerol, and methanol with various diluents, 10% DMSO and 300 mM glucose yielded the highest post-thaw sperm motility. The combination of 10% glycerol and 300 mM sucrose yielded significantly higher post-thaw sperm motility than did combinations using other diluents. Glycerol and DMSO at a concentration of 10% as CPAs with 300 mM glucose as the diluent resulted in the highest MSR and sperm activity index (SAI). An investigation to determine the effects of glycerol and DMSO concentrations on post-thaw sperm survival rate revealed no significant differences among 5, 10, 15, and 20% concentrations of either CPA. In assessing the effects of CPA concentration on the fertilization rate, the 10% concentration yielded the highest fertilization rate (81.4 ± 4.3%) in DMSO, whereas 15% was the optimal concentration for glycerol (fertilization rate = 66.7 ± 6.1%). The hatching rate was also highest in 10% DMSO (40.1 ± 0.4%) and in 15% glycerol (27.8 ± 2.3%). In conclusion, the optimal rates of post-thaw sperm motility, fertilization, and hatching were achieved when E. akaara sperm were cryopreserved in a diluent of 300 mM glucose with 10% DMSO as the CPA at a freezing rate of −5 °C/min. We therefore recommend this protocol for the cryopreservation of E. akaara sperm. more...

Among the carotenoid biosynthesis genes, crtI gene encodes the phytoene desaturase (CrtI) enzyme, and phytoene desaturase convert phytoene to lycopene. Phytoene desaturase is involved in the dehydrogenation reaction, in which four single bonds in the phytoene are introduced into a double bond, eliminating eight hydrogen atoms in the process. Phytoene desaturase is one of the key regulating enzyme in carotenoid biosynthetic pathway of various carotenoid biosynthetic organisms. The crtI gene in genomic DNA of Paracoccus haeundaensis was amplified and cloned into a T-vector to analyze the nucleotide sequence. As a result, the crtI gene coding for phytoene desaturase from P. haeundaensis consists of 1,503 base pairs encoding 501 amino acids residues. An expression plasmid containing the crtI gene was constructed, and Escherichia coli cells containing this plasmid produced the recombinant protein of approximately 55 kDa, equivalent to the molecular weight of phytoene desaturase. The expressed protein in cell lysate showed enzymatic activity similar to phytoene desaturase. Phytoene and lycopene were analyzed by HPLC and measured at wavelength of 280 nm and 470 nm, respectively. The Km values for phytoene and NADPH were 11.1 μM and 129.3 μM, respectively. more...

Astaxanthin is one of the major carotenoids used in pigment has a great economical value in pharmaceutical markets, feeding, nutraceutical and food industries. This study was to increase the production of astaxanthin by co-expression with transformed Escherichia coli using six genes involved in the non-mevalonate pathway. Involved in the non-mevalonate biosynthetic pathway of the strain Kocuria gwangalliensis were cloned dxs, ispC, ispD, ispE, ispF, ispG, ispH and idi genes in order to increase astaxanthin production from the transformed E. coli. And co-expression with the genes to compared the amount of astaxanthin production. This engineered E. coli, containing both the non-mevalonate pathway gene and the astaxanthin biosynthesis gene cluster, produced astaxanthin at 1,100 μg/g DCW (dry cell weight), resulting in approximately three times the production of astaxanthin. more...

Glutathione S-transferase (GST; EC 2.5.1.18) isoenzymes represent a complex group of proteins that are involved in phase II detoxification in several organisms. In this study, GST kappa (GSTκ) from the disk abalone (Haliotis discus discus; AbGSTκ) was characterized at both the transcriptional and functional levels to determine its potential capacity to perform as a detoxification agent under conditions of different stress. The predicted AbGSTκ protein consists of 227 amino acids, with a predicted molecular weight of 25.6 kDa and a theoretical isoelectric point (pI) of 7.78. In silico analysis reveals that AbGSTκ is a disulfide bond formation protein A (DsbA), consisting of a thioredoxin domain, GSH binding sites (G-sites), and a catalytic residue. In contrast, no hydrophobic ligand binding site (H-site), or signal peptides, were detected. AbGSTκ showed the highest sequence identity with the orthologue from pufferfish (Takifugu obscurus) (60.0%). In a phylogenetic tree, AbGSTκ clustered closely together with other fish GSTκs, and was evolutionarily distanced from other cytosolic GSTs. The predicted three-dimensional structure clearly demonstrates that the dimer adopts a butterfly-like shape. A tissue distribution analysis revealed that GSTκ was highly expressed in the digestive tract, suggesting it has detoxification ability. Depending on the tissue and time, AbGSTκ showed different expression patterns, and levels of expression, following challenge of the abalone with immune stimulants. Enzyme kinetics of the purified recombinant proteins demonstrated its conjugating ability using 1-Chloro-2,4-dinitrobenzene (CDNB) and glutathione (GSH) as substrates, and suggested it has a low affinity for both substrates. The optimum temperature and pH for the rAbGSTκ GSH: CDNB conjugating activity were found to be 35 °C and pH 8, respectively indicating that the abalone is well adapted to a wide range of environmental conditions. Cibacron blue (100 μM) was capable of completely inhibiting rAbGSTκ (100%) with an IC50 (half maximal inhibitory concentration) of 0.05 μM. A disk diffusion assay revealed that rAbGSTκ could significantly protect cells from H2O2, CdCl2, and ZnCl2. Altogether, this current study suggests that AbGSTκ is involved in detoxification and immunological host defense mechanisms and allows abalones to overcome stresses in order for them to have an increased chance of survival. more...

RNA isolation from the hepatopancreas of adult abalone is challenging, as indicated by the variable results of reverse transcription-polymerase chain reaction (RT-PCR) amplification. In this study, three RNA isolation methods were tested to evaluate their usefulness in RNA isolation from various abalone tissues. Unlike the conventional method (method I), methods II and III included additional centrifugation and lithium chloride precipitation steps, respectively. RNA quality assessment based on the RT-PCR amplification of ribosomal protein L3 (RPL3) showed little difference in the quality of RNA isolated from muscle, regardless of the isolation method used. While RNA isolated from the hepatopancreas using methods I and II resulted in lower levels of RPL3 amplification, method III was found to be a more effective method of RNA extraction from the hepatopancreas, as indicated by a 30–60-fold increase in the RPL3 level. Competitive inhibition experiments using mixtures of RNA prepared by each method were performed to investigate which RT-PCR step was inhibited by materials present in the RNA preparation. An almost complete absence of RPL3 amplification was observed in RT-PCR with a cDNA template prepared from a mixture of RNAs containing a small amount of hepatopancreatic RNA isolated using method I. A drastic decrease in the incorporation of a fluorescence-labeled nucleotide into cDNA was also evident in the reverse transcription containing hepatopancreatic RNA isolated using method I. These results indicate a distinct inhibition of cDNA synthesis by materials present in the hepatopancreatic RNA preparation isolated using method I, but not present when method III is used. A competitive inhibition experiment was performed using mixtures of cDNA prepared from RNA isolated by each method to investigate whether the materials used in the preparation inhibited the polymerase chain reaction (PCR) step. The level of RPL3 amplification was proportional to the amount of cDNA prepared from hepatopancreatic RNA isolated using method III. The comparable degree of amplification regardless of the amount of cDNA prepared from RNA isolated using method I, together with the low cDNA synthesis in the latter, indicated that it had little, if any, inhibitory effect on the PCR step. This study reports an RNA isolation method that is applicable to the hepatopancreas and other abalone tissues with similar efficacy. more...

Genes that influence the growth of Pacific abalone (Haliotis discus hannai) may improve the productivity of the aquaculture industry. Previous research demonstrated that the differential expression of a gene encoding a C-type lectin domain-containing protein (CTLD) was associated with a faster growth in Pacific abalone. We analyzed this gene and identified an open reading frame that consisted of 145 amino acids. The sequence showed a significant homology to other genes that encode CTLDs in the genus Haliotis. Expression profiling analysis at different developmental stages and from various tissues showed that the gene was first expressed at approximately 50 days after fertilization (shell length of 2.47 ± 0.13 mm). In adult Pacific abalone, the gene was strongly expressed in the epipodium, gill, and mantle. Recombinant Pacific abalone CTLD purified from Escherichia coli exhibited antimicrobial activity against several Gram-positive bacteria (Bacillus subtilis, Streptococcus iniae, and Lactococcus garvieae) and Gram-negative bacteria (Vibrio alginolyticus and Vibrio harveyi). We also performed bacterial agglutination assays in the presence of Ca2+, as well as bacterial binding assays in the presence of the detergent dodecyl maltoside. Incubation with E. coli and B. subtilis cells suggested that the CTLD stimulated Ca2+-dependent bacterial agglutination. Our results suggest that this novel Pacific abalone CTLD is important for the pathogen recognition in the gastropod host defense mechanism. more...

Abalones are edible shellfish and a valuable food source in Asian countries. Although substances from abalone have bioactivities, such as anti-oxidation and anti-inflammation, anti-metastatic effects of abalone have not been fully revealed. Gastric cancer is a common malignant cancer, but prognosis is poor because of its high metastatic characteristics. In this study, a novel peptide (A2) from abalone (Haliotis discus hannai) was applied to investigate its antimetastatic effects in MKN-28 gastric cancer cells. Enhanced activities of glycogen-synthase kinase 3β(GSK-3β) by A2 treatment contributed to modulation of β-catenin; hence, β-catenin signaling was downregulated, and translocation of β-catenin to the nucleus was repressed. Moreover, cellular protrusions including lamellipodia and filopodia were disrupted through downregulation of Rac1 and Cdc42 in response to A2 in MKN-28 cells. It is suggested that A2 inhibits cell migration through controlling levels of β-catenin, GSK-3β, and also induced disorganization of lamellipodia and filopodia. Therefore, A2 possesses therapeutic properties to treat gastric cancer. more...

Experiments were carried out examine short-term effects of human chorionic gonadotropin (hCG) and long-term effects of luteinising hormone releasing hormone analogue (LHRHa) on milt production of the tongue sole Cynoglossus semilaevis. In the first experiment, each fish was implanted with a blank cholesterol pellet (control), 100 and 200 μg LHRHa per kg body weight. In the second experiment, fish were injected with either 100, 200, 400 and 800 IU hCG per kg body weight or same volume of marine fish Ringer’s solution. In the first experiment, milt volume was increased in male implanted with 200 μg LHRHa pellet compared with other groups at day 10. Injection of 400 and 800 IU hCG resulted in an increase in the milt volume at hour 96 after the treatment. Although statistical difference is unable to confirm because of small milt volume, compared with the control group, hormone pellet-treated groups had a reduction in the mean spermatocrit (Sct) and sperm concentration (Sc). The results suggest that the increase in milt volume is at least partially gonadotropin (GtH)-dependent and increased milt volume has a relationship with milt hydration.Key words : Tongue sole, Cynoglossus semilaevis, spermiation, hormoneCorresponding author: 061-450-2395, limhk@mokpo.ac.kr2013 . more...

Growth rates of Pacific abalone Haliotis discus hannai are an important trait affecting the economic value in the abalone aquaculture industry. A reverse-transcription polymerase chain reaction (RT-PCR) analyses of tissues from H. discus hannai was conducted for sexually mature gonads to determine male- and female-specific target gene expression, including genes encoding zona pellucida domain 4 (zp4), sperm protein (sp) and lysin (lys), respectively. Sex-specific expression patterns of these gene expression, even in sexually immature abalone, indicate these genes can be used as sensitive and robust sex-specific molecular markers. The RT-PCR procedure was also performed to analyze tissues collected at various developmental stages (50-day intervals) beginning at fertilization to determine when sex differentiation and expression of sex-specific genes was initiated. Detection of zp4 transcript in tissues collected at 200 days post-fertilization (dpf) indicated egg-specific development starts at 150–200 dpf. To evaluate possible sex-specific differences in growth rate, there was conducting of a molecular marker-based sex identification of abalone from a population selected for rapid growth rate. In a group of large H. discus hannai, females were more prevalent than males. To assess the correlation between growth and sex, there was comparison of weights of 3-year-old Pacific abalone in specimens where there had been sex determinations by visual examination and molecular methods. The results indicated females weighed more (55.92 ± 9.38 g, n = 15) than males (43.64 ± 15.55 g, n = 6, P = 0.037), indicating females had a more rapid growth rate than males. more...

This study was performed as part of the effort to develop artificial seed production techniques for stone flounder Kareius bicoloratus, which has a great potential for farming in northeast Asian countries. To develop a sperm cryopreservation protocol that can be applied for artificial fertilization, we carried out experiments on the key factors for successful fish sperm cryopreservation, including cryoprotective agents (CPAs), diluents, equilibration times, and dilution ratios. The CPAs tested in this study were dimethyl sulfoxide (DMSO), glycerol, methanol, and ethylene glycol, and the diluents were glucose and sucrose. The equilibration times tested in the experiments ranged from 0 to 210 s and the dilution ratios ranged from 1:1 to 1:1000. According to the results of our experiments, the optimal CPA for stone flounder sperm cryopreservation was DMSO in concentrations ranging from 7.5% to 10% when 300 mM glucose was used as diluent and DMSO in concentrations ranging from 15% to 17.5% when 300 mM sucrose was used as diluent. Post-thaw sperm motility was high, with equilibration times up to 150 s, and dilution ratios up to 1:10 (semen:CPA + diluent) showed no significant differences in the effect on post-thaw sperm motility. The cryopreserved sperm showed more significant DNA damage than the fresh sperm with the severity of DNA damage being in inverse proportions to post-thaw sperm motility and survival rate. It is expected that these results will be useful for applications of artificial fertilization at stone flounder hatchery farms. more...

Advances in the optimization of abalone culture can be achieved through a deeper understanding of the molecules modulating physiological functions including growth, metabolism, and reproduction. To identify neuropeptide molecules that play key roles in the modulation, transcriptome analysis of the ganglia (e.g., cerebral and pleuropedal ganglia) of the abalone Haliotis discus hannai was performed. The long-read single-molecule real-time sequencing using the PacBio RSII platform generated 48,344 full-length transcripts, with an N50 length of 3,020 nucleotides (nt), a GC ratio of 44.76%, and a size range of 309–17,545 nt. Of these transcripts, 32,901 (68.1%), 40,515 (83.8%), 7,591 (15.7%), and 14,945 (30.9%) were annotated using the NCBI nonredundant, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Cluster of Orthologous Groups databases, respectively. Using in silico data mining, 18 putative neuropeptide genes were identified from the transcriptome of H. discus hannai. Comparative analysis revealed that the sequences of identified neuropeptides of H. discus hannai were conserved with other molluscan neuropeptide homologs; however, some features of H. discus hannai neuropeptides were found distinct from those of other molluscan neuropeptides. Interestingly, this is the first study to report a precursor encoding a DYamide peptide in molluscan, which is likely to be a homolog of DLamide peptides, which have been discovered only in annelids to date. This study provides comprehensive neuronal transcriptome data for H. discus hannai, which could help improve aquaculture methods both practically and economically by providing a basis for neuroendocrine-based strategies. more...

The present study was designed to examine the potential for inducing ovulation in starry flounder (Platichthys stellatus) using gonadotropin-releasing hormone analog (GnRHa) and human chorionic gonadotropin (hCG) to assess whether starry flounder are differentially responsive to GnRHa and hCG. Female starry flounder were injected or implanted with different doses of hCG or GnRHa pellets to examine their ovulation-inducing potential and effects on plasma levels of testosterone (T), 17β-estradiol (E2), and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP). Blood samples were collected for up to 10 or 25 days post-injection or post-implantation in two separate experiments designed to mimic the early and middle stages of spawning, respectively. Fish treated with the GnRHa pellets (100 µg) showed a significant increase in the total number of stripped eggs relative to the controls. GnRHa administration had no effect on the floating rate or fertilization rate of ovulated eggs in the both experiments, whereas hCG injection affected both of these rates. Plasma T levels were not significantly different between the exogenous hormone-treated and control fish. In contrast, the plasma E2 level was elevated in those fish treated with GnRHa, regardless of injection or implantation, and was accompanied by increased numbers of stripped eggs in both experiments. Treatment with GnRHa resulted in higher 17,20βP levels compared to the controls, and there was a positive relationship between elevated plasma 17,20βP and an increase in ovulated eggs in response to GnRHa treatment. The implantation of starry flounder with GnRHa-containing pellets was effective at inducing sustained ovulation compared to hCG treatment. more...

These studies were conducted to compare the radulae of six species (Nordotis madaka, N. gigantea, N. discus discus, N. discus hannai, Sulculus diversicolor diversicolor, and S. diversicolor supertexta) of the family Haliotidae in Korea using the scanning electron microscope. As a result, teeth of all species has asymmetry rhipidoglossate form and basic tooth formula of six Haliotids was >50-5-1-5-50 more...

A phytoene synthase gene, crtB, was isolated from Kocuria gwangalliensis. The crtB with 1,092 bp full-length has a coding sequence of 948 bp and encodes a 316-amino-acids protein. The deduced amino acid sequence showed a 70.9% identity with a putative phytoene synthase from K. rhizophila. An expression plasmid, pCcrtB, containing the crtB gene was constructed, and E. coli cells containing this plasmid produced the recombinant protein of approximately 34 kDa , corresponding to the molecular mass of phytoene synthase. Biosynthesis of lycopene was confirmed when the plasmid pCcrtB was co-transformed into E. coli containing pRScrtEI carrying the crtE and crtI genes encoding lycopene biosynthetic pathway enzymes. The results obtained from this study will provide a base of knowledge about the phytoene synthase of K. gwangalliensis and can be applied to the production of carotenoids in a non-carotenoidproducing host. more...

The Pacific abalone Haliotis discus hannai is used for commercial aquaculture in Korea. We examined the transcriptome of Pacific abalone Haliotis discus hannai siblings using NGS technology to identify genes associated with high growth rates. Pacific abalones grown for 200 days post-fertilization were divided into small-, medium-, and large-size groups with mean weights of 0.26 +/- 0.09 g, 1.43 +/- 0.405 g, and 5.24 +/- 1.09 g, respectively. RNA isolated from the soft tissues of each group was subjected to RNA sequencing. Approximately 1%-3% of the transcripts were differentially expressed in abalones, depending on the growth rate. RT-PCR was carried out on thirty four genes selected to confirm the relative differences in expression detected by RNA sequencing. Six differentially-expressed genes were identified as associated with faster growth of the Pacific abalone. These include five up-regulated genes (including one specific to females) encoding transcripts homologous to incilarin A, perlucin, transforming growth factor-beta-induced protein immunoglobulin-heavy chain 3 (ig-h3), vitelline envelope zona pellucida domain 4, and defensin, and one down-regulated gene encoding tomoregulin in large abalones. Most of the transcripts were expressed predominantly in the hepatopancreas. The genes identified in this study will lead to development of markers for identification of high-growth-rate abalones and female abalones. more...

Changes of oxygen consumption in juvenile giant grouper, Epinephelus lanceolatus were investigated in order to find out the physiological responses associated with freshwater and low salinities acclimation. Salinity changes in this experiment were set as follows; 35 psu (Exp. Ⅰ) as control, decrease in the manners of 35→20→10→0 psu (Exp. Ⅱ), 35→10→0 psu (Exp. Ⅲ) and 35→0 psu (Exp. Ⅳ). The average oxygen consumption at 27℃ in Exp. Ⅰ (control) was 106.9±0.7 mg   /kg/h. In Exp. Ⅱ, according to the changes of 35→20→10→0 psu in freshwater acclimation, fish showed the gradual decrease in oxygen consumption as 108.1±2.1, 99.6±2.9, 74.6±0.9 and 62.7±1.0 mg   /kg/h, respectively. The fish in Exp. Ⅲ also revealed the same tendency as 106.5±1.3, 77.0±1.2 and 64.7±1.2 mg   /kg/h, respectively. In Exp. Ⅳ, fish showed the decreased oxygen consumption from 109.0±0.9 mg   /kg/h of 35 psu to 71.6±2.0 mg   /kg/h of 0 psu. Giant grouper is thought to be a diurnal fish species, because the level of oxygen consumption during light period was higher than that during dark period.Key words : Giant grouper, Epinephelus lanceolatus, Oxygen consumption, Salinity changeCorresponding Author : 82-61-450-2395, limhk@mokpo.ac.kr, , , Golden Seed Project . more...

In this study, we identified four canonical calmodulin genes in the Pacific abalone, Haliotis discus hannai. Their full-length cDNAs were variable in the 5′ and 3′ untranslated regions, but highly similar (91–97%) in the coding region. Each of the genes encoded 149 amino acids, with 93–97% similarity among themselves and 94–98% similarity with human CAM I. There were 54 substitutions distributed unevenly throughout the coding regions, found mostly in the third codon position. Gene structure analysis revealed that each of the calmodulin genes comprised five exons and four introns. The intron positions and phases were identical and there were no introns in the fourth exon. The corresponding introns differed in their sequences and sizes. Expression profiles of nine tissues from abalone revealed that the calmodulin genes were transcribed in common in gill and mantle tissue, but differentially in the other tissues. A phylogenetic analysis based on the amino acid sequences revealed that calmodulin C was the most common isoform in Gastropoda and calmodulin was the most diverged isoform. An in silico analysis of the calmodulin genes identified paralogous genes in other Haliotis species, indicating that gene duplication might have occurred in the last common ancestor of Haliotis. Abbreviations: ORF: open reading frame; RACE: random amplification of cDNA end; TSA: transcriptome shotgun assembly; UTR: untranslated region more...

We report the draft genome sequences of a novel member of the Picornavirales isolated from Pacific abalone (Haliotis discus hannai). The full length of the assembled draft genome sequences, obtained by use of a next-generation sequencing technique, were 8,019 nucleotides, including an RNA-dependent RNA polymerase gene (5,088 nucleotides) and a capsid protein gene (2,553 nucleotides). This genome sequence will be useful for understanding viral disease of Pacific abalone. more...

We report the draft genome sequences of a novel member of the Picornavirales isolated from Pacific abalone ( Haliotis discus hannai ). The full length of the assembled draft genome sequences, obtained by use of a next-generation sequencing technique, were 8,019 nucleotides, including an RNA-dependent RNA polymerase gene (5,088 nucleotides) and a capsid protein gene (2,553 nucleotides). This genome sequence will be useful for understanding viral disease of Pacific abalone. more...

This study is aimed to analyze the economic performance of black rockfish aquaculture by standardizing cost structures by region and farming size. The result of survey on farming and sale condition in each region, stocking density, survival rate, juvenile price, and unit production was the highest at Yeosu and Tongyeong, Heuksando showed the lowest. While rearing period was the longest at Tongyeong, the shortest region was Yeosu and Wando. In farming cost structure by region, amount of feeing was the highest at Tongyeong and Yeosu, and the lowest was Heuksando. Cost of medicine was high in Wando and Taean region, Yeosu and Hecksando was low. In case of farm size, feed cost ratio was high in the order of medium(0.75ha), small(0.25ha) and large(1.25ha) size. Standard production cost at every farm size of Heuksando showed the lowest among these regions. Taean and Yeosu was middle, and Tongyeong and Wando was the highest. According to the income, profit rate and investment return of farm size in all regions, as the bigger farm size, the higher income and profit rate was revealed. However, in case of Wando, Taean, and Heuksando which regions has high investment return, medium farm size was higher than large size. The result of economic analysis according to various factors, economic feasibility of black rockfish aquaculture in marine floating cage was showed significant changes by rearing and market condition. more...