제주도내 넙치양어장에 빈발하여 피해를 입히는 에드와드병의 원인균인 Edwardsiella tarda의 출현 시기와 분포를 알기 위하여, 1997년 6월부터 1998년 5월가지 제주도내 5개 넙치양어장에서 사용하고 있는 해수(주입수, 사육수, 배출수)와 사육중인 넙치의 장기조직 (간장, 비장, 신장, 장)을 조사하였다. 조사 방법은 해수인 경우는 DSSS배지에 직접 도말하는 방법과, 증균 배양후 도말하는 방법으로 균수를 계수하였고, 장기 조직은 각 장기를

1992년 9월부터 1993년 8월까지 군산항을 기지로 한 소형어선이 한국서해안 격열비열도 근해에서 어획한 돌가자미를 매월 약 20마리씩 정기적으로 채집한 총 248마리의 연령과 성장에 관하여 조사분석한 결과를 요약하면 다음과 같다. 1. 이석의 투명대가 형성되는 시기는 1~2월이고 불투명대가 형성된 시기는 11월이었다. 2. 이석반경(R)과 체장(SL)과의 사이에는 자웅별로 다음과 같은 관계식이 성립하였다. Male SL=84.1R super (1.01) (r super (2) = 0.74) Female SL=80.1R super (1.07) (r super(2) =0.76) 3. 전장(TL)과 체장(SL)과의 사이에는 다음과 같은 관계식이 성립하였다. Male TL=1.15SL+9.6(r super (2)=0.99) Female TL=1.14SL+10.0(r super(2)=0.99) 4. 연령별 체장(Lt)과 연령(t)을 von Bertalanffy 성장식에 적용하여 다음과 같은 관계식을 구하였다. Male Lt=313.7(1-exp{-0.463(t+0.0704)}] Female Lt=478.6[1-exp{-0.286(t-0.1619)}]

A new embryonic cell line (OFEC-17FEN) derived from olive flounder Paralichthys olivaceus was developed. OFEC-17FEN cells were subcultured for <30 passages over ~200 days. OFEC-17FEN cells had a doubling time of 114.34 h and modal diploid chromosome number was 48. The pluripotency genes POU5f1 and NANOG were expressed in OFEC-17FEN cells. However, the lack of several pluripotency-related genes expression indicates that OFEC-17FEN cells are not stem cells. OFEC-17FEN cells transfected with plasmid pEGFP-c1 exhibited a strong green fluorescent signal at 48 h after transfection. Accordingly, OFEC-17FEN cells may be useful for both basic research and biotechnological application.

In a 12-week experiment, the rock bream, Oplegnathus fasciatus, and olive flounder, Paralichthys olivaceus, were investigated to determine the effects of starvation on their physiological parameters. The protein and DNA contents of the starved fish were significantly higher than the initial values and those of the fed fish. The RNA contents and RNA/DNA ratios of the fed fish were significantly higher than those of the other groups (P<0.05). The hematocrit, hemoglobin, red blood cells (RBC), and mean corpuscular volume (MCV) of the fed rock bream were significantly higher than at baseline (P<0.05), whereas the mean corpuscular hemoglobin concentration (MCHC) of the fed fish was lower than at baseline (P<0.05). The hematocrit, hemoglobin, RBC, and MCHC of the starved group were significantly lower than the baseline values, whereas the MCV of the starved group was significantly higher than the baseline value (P<0.05). No significant difference in alanine aminotransferase was observed between the fed fish and baseline, whereas the starved fish value was significantly higher than the baseline value (P>0.05). There were no significant differences in cortisol levels. However, the glucose level in the fed group was significantly higher than the baseline level and that in the starved group was significantly lower than the baseline level (P<0.05).

The optimum concentrations of clove oil as an anesthetic for olive flounder (Paralichthys olivaceus) and the stress response of the fish to clove oil anesthesia were determined over a range of water temperatures, and investigated in a simulated transport experiment using analysis of various water and physiological parameters. While the time for induction of anesthesia decreased significantly as both the concentration of clove oil and water temperature increased, the recovery time increased significantly (P<0.05). The plasma cortisol concentration in fish at each temperature increased significantly up to 12 h following exposure (P<0.05), then decreased to 48 h (P<0.05). The DO dissolved oxygen concentrations, pH values, and the fish respiratory frequencies decreased over 6 h following exposure to clove oil in all experimental groups (P<0.05), whereas the NH4 + and CO2concentrations in all experimental groups increased up to 6 h (P<0.05). The pH values and DO concentrations increased with increasing clove oil concentration (P<0.05) in the 6 h following exposure, and the CO2 and NH4 + concentrations and the respiratory frequencies decreased with increasing clove oil concentration (P<0.05). The results of this experiment suggest that clove oil reduced the metabolic activity of olive flounder, thus reducing NH4 + excretion and O2 consumption. In conclusion, clove oil appears to be a cost-effective and efficient anesthetic that is safe for use and non-toxic to the fish and users. Its use provides the potential for improved transportation of olive flounder.

The antimicrobial effects of ten isothiocyanates (ITCs) present in cruciferous vegetables and radish root hydrolysate were investigated against pathogenic bacteria from olive flounder. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured against two gram-positive bacterial strains (Streptococcus parauberis, S. iniae) and four gram-negative bacterial strains (Edwardsiella tarda, Vibrio ichthyoenteri, V. harveyi, Photobacterium damselae) by using a broth microdilution technique. The antibacterial activity of ITCs was in the order sulforaphane > sulforaphene > phenylethyl ITC > erucin > benzyl ITC > iberin > I3C > allyl ITC > phenyl ITC > hexyl ITC. The susceptibility of fish pathogens to ITCs was in the order of V. harveyi > E. tarda > P. damselae > S. parauberis > S. iniae > V. ichthyoenteri. Antimicrobial activity (MIC) of radish root hydrolysate was 0.250 mg/mL against S. iniae, 0.438 mg/mL against S. parauberis, and 0.500 mg/mL against both E. tarda and V. harveyi. The aliphatic ITCs were potent inhibitors of the growth of fish pathogens, followed by aromatic ITCs and indolyl ITC. The presence of a double bond in the chemical structure of ITCs decreased antibacterial activity, while ITCs with a thiol (-S-) group and a longer carbon chain increased antibacterial activity. These results suggest that ITCs have strong antibacterial activities and may be useful in the prevention of fish pathogens.

We assessed the effects of various dietary conditions on the growth, phenotypic traits, and morphometric dimensions of rock bream, Oplegnathus fasciatus and on the morphometric dimensions of sectioned olive flounder, Paralichthys olivaceus. Rock bream in the fed group increased in body weight, standard length, and condition factor, but these parameters decreased significantly for fish in the starved group (P < 0.05). The head connection dimensions of fish in the fed group decreased, while for starved fish there was increase in external morphometric dimensions (P < 0.05). In both species, sectioned morphometric analysis revealed that fish in the fed group had a larger body circumference and cross-cut sectional area, and greater cross-cut section height, relative to the starved group (P < 0.05).

This study investigated possible involvement of photoperiodic regulation in reproductive endocrine system of female olive flounder. To investigate the influence on brain-pituitary axis in endocrine system by regulating photoperiod, compared expression level of Kisspeptin and sbGnRH mRNA in brain and FSH-β, LH-β and GH mRNA in pituitary before and after spawning. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from Aug. 2013 to Jun. 2014. Continuous long photoperiod treatment from Aug. (post-spawning phase) was inhibited gonadal development of female olive flounder. In natural photoperiod group, the Kiss2 expression level a significant declined in Mar. (spawning period). And also, FSH-β, LH-β and GH mRNA expression levels were increasing at this period. However, in long photoperiod group, hypothalamic Kiss2, FSH-β, LH-β and GH mRNA expression levels did not show any significant fluctuation. These results suggest that expression of hypothalamic Kiss2, GtH and GH in the pituitary would change in response to photoperiod and their possible involvement of photoperiodic regulation in reproductive endocrine system of the BPG axis.

To successful molecular breeding, identification and functional characterization of breeding related genes and development of molecular breeding techniques using DNA markers are essential. Although the development of a useful marker is difficult in the aspect of time, cost and effort, many markers are being developed to be used in molecular breeding and developed markers have been used in many fields. Single nucleotide polymorphisms (SNPs) markers were widely used for genomic research and breeding, but has hardly been validated for screening functional genes in olive flounder. We identified single nucleotide polymorphisms (SNPs) from expressed sequence tag (EST) database in olive flounder; out of a total 4,327 ESTs, 693 contigs and 514 SNPs were detected in total EST, and these substitutions include 297 transitions and 217 transversions. As a result, 144 SNP markers were developed on the basis of 514 SNP to selection of useful gene region, and then applied to each of eight wild and culture olive flounder (total 16 samples). In our experimental result, only 32 markers had detected polymorphism in sample, also identified 21 transitions and 11 transversions, whereas indel was not detected in polymorphic SNPs. Heterozygosity of wild and cultured olive flounder using the 32 SNP markers is 0.34 and 0.29, respectively. In conclusion, we identified SNP and polymorphism in olive flounder using newly designed marker, it supports that developed markers are suitable for SNP detection and diversity analysis in olive flounder. The outcome of this study can be basic data for researches for immunity gene and characteristic with SNP.

The immune system in teleost fish is not completely developed during embryonic and larval stages, therefore effective innate mechanisms is very important for survival in such an environment. However, the knowledge of the development of immune system assumed to be restricted. In many species, lysozymes have been considered as important genes of the first line immune defense. The early detection of lysozyme mRNA in previous reports, led to the investigation of its presence in oocytes. As a result, c-type lysozyme mRNA transcripts were detected in unfertilized oocytes indicating maternal transfer. Therefore, we investigated the expression patterns of lysozymes in flounder, including the matured oocyte. In our results, c-type lysozyme mRNA was first detected in unfertilized oocyte stage, observed the significantly decreased until hatching stage, and was significantly increased after hatching stage. On the other hand, g-type lysozyme mRNA transcripts were first detected at late neurula stage, and the mRNA level was significantly increased after 20 dph. It may be suggest that maternally supplied mRNAs are selectively degraded prior to the activation of embryonic transcription. This study will be help in understanding the maturation and onset of humoral immunity during development of olive flounder immune system.

The early growth response protein 1 (Egr-1) is a widely reported zinc finger protein and a well known transcription factor encoded by the Egr-1 gene, which plays key roles in many aspects of vertebrate embryogenesis and in adult vertebrates. The Egr-1 expression is important in the formation of the gill vascular system in flounders, which develops during the post-hatching phase and is essential for survival during the juvenile period. However, the complete details of Egr-1 expression during embryo development in olive flounder are not available. We assessed the expression patterns of Egr-1 during the early development of olive flounders by using reverse transcription polymerase chain reaction (RT-PCR) analysis. Microscopic observations showed that gill filament formation corresponded with the Egr-1 expression. Thus, we showed that Egr-1 plays a vital role in angiogenesis in the gill filaments during embryogenesis. Further, Egr-1 expression was found to be strong at 5 days after hatching (DAH), in the development of the gill vascular system, and this strong expression level was maintained throughout all the development stages. Our findings have important implications with respect to the biological role of Egr-1 and evolution of the first respiratory blood vessels in the gills of olive flounder. Further studies are required to elucidate the Egr-1-mediated stress response and to decipher the functional role of Egr-1 in developmental stages.

Reactive oxygen species (ROS) are produced in organisms as the natural products of oxidative metabolism by environmental stress and pathogen invasion. ROS, such as superoxide anion and hydrogen peroxide, can be toxic to cells and tissues to cause oxidative stress. Recent study revealed that olive flounder (Paralichthys olivaceus) superoxide dismutase (SOD) has been identified as a partial gene and strongly induced to benzoin[a]pyrene and it was deduced indicator of aquatic oxidative stress responses, but its transcriptional response against viral infection has not been investigated. In the present study, spatial and temporal expression profile was analyzed to investigate the function of Of-SOD in the anti-viral response. Of-SOD transcripts were ubiquitously detected in diverse tissues with variable levels using a real-time PCR. The expression of Of-SOD was significantly higher in the muscle, liver and brain, but extremely low in the stomach and spleen. Following VHSV challenge, the expression of Of-SOD increased within 3 hours and subsequently decreased to the original level at 2 days post-challenge in kidney. Although expression pattern and induction time are slight differences depending on the tissue, the transcript of Of-SOD was consistently increased in acute infection response, but expression is low in the chronic response. Collectively, Of-SOD expressions were inducible after VHSV infection and they were probably involved in the immune response against viral challenge. These results suggest that SODs may play important roles in the immune defense system of P. olivaceus and perhaps contribute to the protective effects against oxidative stress in this flounder.

Molecular markers are useful for selecting to include superior character genetic like as strong immune system and rapid growth in fish. The marker is also very important part of breeding technology in Olive flounder (Paralichthys olivaceus). Single nucleotide polymorphisms (SNPs) marker is already in use widely for genomic research and breeding. But this SNPs marker hardly has been validated for screening functional genes in Olive flounder. We study identify single nucleotide polymorphisms (SNPs) on Expressed sequence tag (EST) database, develop usable SNP marker and apply to wild sample and cultured of olive flounder. As a result, Out of total 4.327 ESTs, 693contigs and 514 SNP from total contigs were detected while these substitutions include 297 transitions and 217 transversions. 144 developed markers were applied in 16 samples (wild 8, culture 8), Out of total marker, only 32 markers had detected polymorphic in sample. Polymorphism of 32 markers was observed in the variety genes region involved in immunity and protein synthesis. And the 32 marker were identified 21 transitions, 11 transversions, and indel was not detected in polymorphic SNPs. The analysis on heterozygosity by sample showed 0.34 in wild sample and 0.29 in cultured sample. In conclusion, we was identified SNP and Polymorphism by designed new marker, it supports that development marker is suitable for SNP detection and diversity analysis in Olive flounder. The outcome of this study can be basic data for researches for immunity gene and characteristic with SNP.

Cardiovascular system is the primary organ to develop and reach a functional state, which underscores the essential role of the vasculature in the developing embryo. The vasculature is a highly specialized organ that functions in a number of key physiological works including the carrying of oxygen and nutrients to tissues. It is closely involved in the formation of heart, and hence it is essential for survival during the hatching period. The expression of genes involved during vascular development in the olive flounder (Paralichthys olivaceus) in the days after hatching is not fully understood. Therefore, we examined the expression patterns of genes activated during the development of flounder. Microscopic observations showed that formation of blood vessels is related to the expression of the vimentin gene. Also, the temporal expression patterns of this vimentin-like gene in the developmental stages and in the normal tissues of olive flounder. The purpose of this study was to examine the expression patterns of vimentin in normal tissues of the olive flounder and during the development of the vascular system in newly hatched olive flounders and HIF-1 plays a vital role in the formation of blood vessels during development. Vimentin expression was strong at the beginning of the development of blood vessels, and was present throughout all developmental stages. Our findings have important implications with respect to the roles of vimentin and HIF-1 in the development and evolution of the first blood vessels in olive flounder. Further studies are required to elucidate the vimentin-mediated hypoxic response signal transduction and to decipher the functional role of vimentin in developmental stages.