• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1997.06a
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• pp.282-284
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• 1997

• Journal of fish pathology
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• v.10 no.1
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• pp.21-29
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• 1997

We investigated on the prevalence and extermination of scuticociliatids parasitic on cultured japanese flounder, Paralichthys olivaceus in land-marine tank system of southern Korea from January to February in 1997. The gills and the skin showed the highest infection rate(60%), and the brain showed the lowest(22%). Also, fish secreted large quantity of mucus with a bleeding and ulcerated lesions on the infected sites. The number of the parasites in inflowing sea water, surface water and bottom water of farming tank ranged 0~1 individuals/$100m\ell$, 0~413 individuals/$100m\ell$ and $7\sim7.3{\times}10^4$ individuals/$100m\ell$, respectively. This parasite was died within 2 hours in 50~500 ppm, 48 hours of 10 ppm formalin or hydrogen peroxide, 1 hour in 50~500 ppm, 80 minutes of 10 ppm oligo chitosan and 10 minute in 100% but did not died until 48 hours in 10~70% fresh water.

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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.15-22
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• 2018

Alpha-pinene is an organic compound that possesses antibiotic and anti-parasitic activities. In this study, we developed a layered nanocomposite to combat against Miamiensis avidus which causes scuticociliatosis in the olive flounder Paralichthys olivaceus. We used a solid-solid reaction to develop the layered nanocomposite, incorporating-pinene ($C_{10}H_{16}$) into organically modified montmorillonite. We used cetyltrimethylammonium cations as the interlayered modifier for the adsorption of hydrophobic pinene molecules. The X-ray diffraction patterns of the nanocomposite structure showed that the basal spacing increased from $9.6{\AA}$ to $30.4{\AA}$. Interestingly, the fraction of ${\alpha}$-pinene released remained constant for a long period of time (228 h) due to the layered nature of the nanocomposite. Additionally, optical microscopic images of the treated scuticociliatids revealed that their cells were lysed, and this effect increased with the increasing concertration of ${\alpha}$-pinene. Histopathological assessment of ${\alpha}$-pinene nanocomposite-treated olive flounder gills revealed no significant morphological changes, even at the highest concentration of the ${\alpha}$-pinene. The nanocomposite has several advantages, including easy handling, high solubility, low toxicity, and the easy formulation of granules or powder, which improve the pesticidal activity of ${\alpha}$-pinene. Collectively, our results suggest that ${\alpha}$-pinene nanocomposite may be a useful treatment against scuticociliatosis.