• Animal cells and systems
• /
• v.8 no.4
• /
• pp.329-333
• /
• 2004

Japanese flounder (Paralichthys olivaceus) head kidney (HK) leukocytes were incubated with $10^3$ to $10^{-3}$ ng levamisole/ml for 4, 24 or 48 h and then assayed for their natural cytotoxic activity against xenogeneic tumor cells. This activity was slightly increased after 24 h of incubation. In a second experiment, fish were fed 0, 75, 150 or 300 mg levamisole/kg diet for 10 consecutive days. The fish were then fed a commercial non-supplemented diet and sampled 0, 1, 2, 3, 4 or 6 weeks post-administration of levamisole. The cytotoxic activity was found to be increased with increasing levamisole dose and remained greatly enhanced until the end of the experiment. In conclusion, levamisole enhanced flounder natural cytotoxic cell activity both in vitro and in vivo and had a great lasting action when administered by feeding.

• Journal of Aquaculture
• /
• v.17 no.3
• /
• pp.209-214
• /
• 2004

Effects of Korean mistletoe, Viscum album coloratum on the non-specific immune responses of Japanese flounder, Paralichthys olivaceus were examined. Flounder were inoculated with mistletoe, Freunds complete adjuvant (FCA), or phosphate-buffered saline (PBS) as a control into their peritoneal cavities. Reactive oxygen intermediate (ROI) products were more enhanced in mistletoe-injected fish kidney phagocytes than in FCA-injected ones. The level of lysozyme activity detected in the serum of fish 4 d after injection with mistletoe was also significantly higher than that found in the serum of the control fish. The appropriate concentration of mistletoe in eliciting the highest level of serum lysozyme activity was 500 $\mu$m/300 g of fish. In phagocytic activity assays, mistletoe-sen-sitized flounder kidney phagocytes captured more yeasts than those of the control fish. Korean mistletoe appeared to be a good activator of the non-specific immune responses of Japanese flounder.

• Journal of fish pathology
• /
• v.6 no.2
• /
• pp.191-195
• /
• 1993

With the rapid progress in seed production techniques, aquaculture production of economically important species of marine fish has been accelerated in Japan. Howecer, mass mortalities due to viral infections as well as other microbial infections have often occurred during the seed production and grow-out stages. Among these diseases, four viral diseases have been known in cultured Japanese flounder (Paralichthys olivaceus) since around 1980. In this paper, viral diseases of cultured flounder in Japan are briefly reviewed, with special attention to two viral diseases. viral epidermal hyperplasia and rhabdovirus infection which are relatively important because of their frequent occurrence. Viral epidermal hyperplasia is characterized by fin opacity and associated with high mortality in larval flounder Electron microscopy of affected epidermal cells and transmission experiments with tissue filtrates demonstrated that the disease was caused by a herpesvirus but the agent has not been isolated in fish cell lines. On the other hand, rhabdovires infection occurrs in juvenile and production size fish with hemorrhage in the skeltal muscle and fins, congestion of the gonads, and ascites. A rhabdovirys was isolated in RTG-2 cells from the diseased flounder as a causative agent, which was designated hirame rhabdovirus (HRV) or Rahbdovirus olivaceus. HRV is serologically distinguishable from other known fish rhabdoviruses. Intensive researches on these viral diseases started in 1980th. but properties of the causative agents and infection mechanisms have not been fully investigated. This results in difficulty in controlling these diseases.

• BMB Reports
• /
• v.42 no.4
• /
• pp.206-211
• /
• 2009

Proopiomelanocortin (POMC) plays an essential role in the stress response of the hypothalamic-pituitary-adrenal axis, and is the precursor of biologically active peptides such as adrenocorticotropin (ACTH), $\alpha$-melanocyte-stimulating hormone ($\alpha$-MSH), $\beta$-melanocyte-stimulation hormone ($\beta$-MSH) and $\beta$-endorphin. We have synthesized two different forms of POMC cDNA clones, POMC-I and POMC-II, from a pituitary cDNA library for Paralichthys olivaceus, or Japanese flounder. jfPOMC-I cDNA consists of 954bp and encodes a polypeptide of 216 amino acid residues, whereas jfPOMC-II consists of 971bp which encode a polypeptide of 194 amino acid residues. The high levels of jfPOMC-I and -II mRNAs detected in the pituitary tissue and moderate levels detected in the brain tissue plus our quantitative RT-PCR analysis, which showed there to be no significant difference between the levels of jfPOMC-I and -II mRNAs, indicate that there may be no functional separation between these two mRNAs in the flounder.

• Fisheries and Aquatic Sciences
• /
• v.25 no.8
• /
• pp.441-449
• /
• 2022

In this study, we investigate the physiological response of olive flounder, Paralichthys olivaceus and Japanese croaker, Nibea japonica, on a series of rising water temperatures (WT). At 1, 9, and 17 days, WT increased from 23℃ (control) to 26, 29 and 32℃ within 6 hours, respectively, and then maintained for 96 hours. At 5, 13, and 21 days, WT decreased from each WT to 23℃ within 6 hours and was maintained at 23℃ for 96 hours. Blood were collected at 0, 1, 5, 9, 13, 17, 21, and 60 days. In both species, hematocrit, red blood cell and hemoglobin of stressed groups were lower than non-stressed group at 13 days. The osmolality of stressed group was lower than non-stressed group at 21 and 60 days. In olive flounder, hemoglobin of stressed groups was lower than non-stressed group at 21 and 60 days, respectively, but osmolality of stressed group was higher than non-stressed group at 9 days. In Japanese croaker, hematocrit, red blood cell and hemoglobin of stressed groups were higher than non-stressed group at 21 and 60 days, respectively, and osmolality of stressed group was higher than that of non-stressed group at 1 day. At 1, 17, and 21 days, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of stressed group were higher than non-stressed group in olive flounder. In Japanese croaker, AST and ALT of stressed group was lower than non-stressed group at 17, 21, and 60 days. The cortisol of olive flounder increased with increasing WT, but those of Japanese croaker increased with decreasing WT. In both species, the glucose increased with increasing WT. After changing WT, lactic acid of olive flounder and Japanese croaker were not significantly different. The physiological response of olive flounder increased directly to the increase in WT, and Japanese croaker contrasted with olive flounder.

• Journal of fish pathology
• /
• v.6 no.2
• /
• pp.219-231
• /
• 1993

The author introduces the preventive and therapeutic methods of diseases in Japanese flounder which have been conducted by the Fish Disease Laboratory, the Mikamewan Fishery Cooperative Union, Ehime Prefecture, since 1982. Prevention 1. Addition of a sand substrate in the culture pond was effective to prevent ulcer disease. 2. Bathing in 0.5ppm of copper ion was effective to prevent some parasites. 3. Low stocking density of the fish reduced an incidence of edwardsiellosis or gliding bacterial disease. 4. Removal of the diseased fish prevented thd spread of lyphoeystis. 5. So-called $\pi$-water was effective to prevent the fry from some diseases. 6. Immersion of the juvenile in a sodium nifrusylate solution during transportation was effective to prevent gliding bacterial disease. Therapy 1. Sodium nifrustylate or oxytetracycline was effective to cure gliding bacterial disease. 2. Bathing in formalin(150ppm) or freshwater was effective to cure scuticociliatidosis. 3. Erythromycin was effective to cure $\beta$-hemolytic Streptococcus sp. infection. 4. Bathing in a hydrogen peroxide solution(1.5%) was effective to cure white spot disease.

• Journal of Aquaculture
• /
• v.14 no.1
• /
• pp.57-64
• /
• 2001

In Paralichthys olivaceus and Nibea japonica, response to live air (5hr) or ship (25hr) transportation was assessed, by determining the levels of plasma cortisol, glucose, lactic acid and osmolality, as well as hematological parameters namely hematocrit (Ht), red blood cell (RBC) count, hemoglobin (Hb), corpuscular volume (MCV), corpuscular hemoglobin (MCH) and corpuscular hemoglobin concentration (MCHC). In the experimental series I, the olive flounder was subjected to stress or no stress for 1hr, prior to its air transportation for 5hr. The stress suffered by the flounder prior to air transportation resulted in significant reduction in Ht, but increases in MCH and MCHC. Air transportation led to increases in MCV and MCH in both the stressed and non stressed groups. In the non stressed group it led to significant increase in Ht but decrease in MCHC. In the stressed group, the air transportation led to significant increases in osmolality and plasma cortisol from 5 to 38.5ng/$m\ell$. Non stressed groups did not show significant differences in this before and after transportation. In the experiment II, the red blood cell (RBC) count ranged from 2.5$\times$10$^{6}$ /${mu}ell$ to 2.7$\times$10$^{6}$ /${mu}ell$ in the flounder and 1.9$\times$10$^{6}$ /${mu}ell$ to 2.1$\times$10$^{6}$ /${mu}ell$ in the croaker during the pre- and post-transportation, respectively. In the croaker the shipping led to significant increase in plasma cortisol from 26 to 35ng/$m\ell$ but decrease in glucose from 91.0 to 26.4mg/㎗. For glucose the reverse (39.0 to 51.0mg/㎗) was true for the flounder.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.6
• /
• pp.794-799
• /
• 2012

The cytochrome P450c17-I (CYP17-I) is one of the enzymes critical to gonadal development and the synthesis of androgens. Two single nucleotide polymorphisms (SNPs) were detected within the coding region of the CYP17-I gene in a population of 75 male Japanese flounder (Paralichthys olivaceus). They were SNP1 (c.C445T) located in exon2 and SNP2 (c.T980C (p.Phe307Leu)) located in exon5. Four physiological indices, which were serum testosterone (T), serum $17{\beta}$-estradiol ($E_2$), Hepatosomatic index (HSI), and Gonadosomatic index (GSI), were studied to examine the effect of the two SNPs on the reproductive endocrines of Japanese flounder. Multiple comparisons revealed that CT genotype of SNP1 had a much lower T level than CC genotype (p<0.05) and the GSI of individuals with CC genotype of SNP2 was higher than those with TT genotype (p<0.05). Four diplotypes were constructed based on the two SNPs and the diplotype D3 had a significantly lower T level and GSI. In conclusion, the two SNPs were significantly associated with reproductive traits of Japanese flounder.

• Journal of fish pathology
• /
• v.7 no.2
• /
• pp.151-160
• /
• 1994

In order to elucidate the patterns of tissue damage evoked by the scuticociliatids, eighteen fingerlings of Japanese flounder, Paralichthys olivaceus, heavily infected with an unidentified scuticociliatid were histopathologically examined. Skin layer with the underlying musculature were severely necrotized due to the infestation of the ciliates. However in the early lesions, both dermis and myofibres remained relatively intact compared with other surrounding loose connective tissues. Mild damages were found in more dense tissues. One or more scuticociliatids were recognized in the blood and lymph vessels of the loose connective tissues with or without destructive changes. Many of nerve trunks or ganglia were also parasitized with less marked histological damage in the parenchyma. Dura and its adjacent tissues in the spinal cord were severely necrotized with massive accumulation of the ciliates in subdural space. The parasitic invasion in the central nervous system was usually confined to the cortical region. In the gill, variable degenerative changes were occurred due to the invasion of the ciliates recognized in the blood vessels of branchial arches or primary filaments. From these results, it was strongly suggested that the scuticociliatids are very actively penetrated into the deep tissues mainly through the severe destruction of the loose connective tissue components and that the vascular system could play a role in the rapid distribution of the ciliates to the remote tissues or organs.

• Fisheries and Aquatic Sciences
• /
• v.12 no.4
• /
• pp.265-275
• /
• 2009

G Protein-coupled receptors (GPCRs) mediating wide ranges of physiological responses is one of the most attractive targets for drug development. Rhodopsin, a dim-light photoreceptor, has been extensively used as a model system for structural and functional study of GPCRs. Fish have rhodopsin finely-tuned to their habitats where the intensity and the wavelength of lights are changed depending on its water-depth. To study the detailed molecular characteristics of GPCR architecture and to understand the fishery light-sensing system, genes encoding rod opsins were isolated from fishes living under different photic environments. Full-length rod opsin genes were obtained by combination of PCR amplification and DNA walking strategy of genomic DNA isolated from olive flounder, P. olivaceus, Japanese eel, A. japonica, and Common carp C. carpio. Deduced amino acid sequences showed a typical feature of rod opsins including the sites for Schiffs base formation (Lys296) and its counter ion (Glu113), disulfide formation (Cys110 and Cys187), and palmitoylation (Cys322 and Cys323) although Cys322 is replaced by Phe in Japanese eel. Comparison of opsins by amino acid sequence alignment indicated the closest similarity between P. olivaceus and H. hippoglossus (94%), A. japonica and A. anguilla (98%), and C. carpio and C. auratus (95%), respectively.