• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.40-40
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• 2003

DNA content of the sperm of tetraploid mud loach (Misgurnus mizolepis) males and the ploidy status of progenies generated by crossing tetraploid males with diploid females are described. Reproductive performance of the induced adult tetraploid males ranged from sterility to fertility. Of 48 tetraploid males tested, 12 were sterile but the other 36 produced functional sperm. Of these 36, 26 produced haploid sperm, which on fertilizing the haploid eggs, generated diploid progenies. Seven tetraploid males were mosaics in their sperm, as indicated by the production of diploid, aneuploid and/or triploid offspring. Only 3 males produced diploid sperm rendering the production of all-triploid progenies. The DNA content of sperm of a tested tetraploid male was consistent throughout the 3 progeny tests, i.e. the haploid sperm-producing 4n males persisted to produce the haploid sperm only likewise the diploid sperm producing4n males consistently produced the diploid sperm only, when progeny testing was extended to 3 successive but alternate years. Hence, a careful and direct examination of the DNA profile of sperm from tetraploid males is a pre-requisite for reproductive containment of genetically modified fish.

• Journal of Aquaculture
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• v.9 no.3
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• pp.293-300
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• 1996

Validities of several gene transfer methods including microinjection, electroporation and lipo-fection with luciferase gene (pRSVL), and effectiveness of mud loach expression vector which contains ARS from mud loach on production of transgenic mud loach were evaluated. Microiniection revealed the $0\~8\%$ of transgene incidence in 2-week-old fish with significant mosaicism. Electroporation and lipofection of mud loach sperm also successfully introduced the transgene into sperm cells, and transferred the foreign DNA into zygote. Gene transfer by electroporation and lipofection showed a range of $0\~28\%$ and $0\~48.1\%$ of transgene incidence, respectively in newly hatched larvae, altough most DNA introduced were gradually degraded with the development of fish. Microinjections of mud loach expression vector caused a significantly reduced survival rate of mud loach embryos with severe teratogenic effects, and ARS/Luc transgene could not be detected in normally developed fish after microinjection.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.170-180
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• 1987

This study was undertaken to determine the effects of HCG and trout pitutary on sexual maturation and ovulation in the Korean loach, Misgurnus anguillicaudatus. Sexual maturation was observed in the fish treated with 250＋125 IU HCG within 2-4 days following injections. Total ovary weight and GSI were significantly greater in the hormone-treated fish than in the control fish. Furthermore, in the hormone-treated fish body weight increased by about 4-9 percent in 2 days. The water content of the ovulated eggs of the fish treated with 250＋125 IU HCG was also greater than that in the control. Changes in both macroscopic & microscopic appearnce of Korean loach ovaries are describled, as well as changes in the gonadosomatic index. Oocytes pass through seven cytologically changes in the relative stages. By examining these stages, it was found that oogenesis occures in two broad phases. The previtellogenic phasebegins as a new oogonia continues to arise following spawning. These rapidly develop into early perinucleolus oocytes, which in turn develop into resting stage oocytes. Most oocytes remain in this stage when they develop into late perinucleolus oocytes. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. Shortly before spawning the final hyaline stage of developing is reached. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance.

• Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.39-46
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• 2001

To examine the effect of copy number-dependent transgenic genotype on the expression of foreign gene, stable hemizygous and homozygous transgenic breeding line was established using artificial parthenogenesis. For this purpose, induced diploid gynogenetic transgenesis was optimized in mud loach (Misgurnus mizolepis) using UV-irradiated cyprinid loach (M. anguillicaudatus) sperm and thermal shocks. Optimum UV range for inactivation of cyprinid loach sperm was between 3,150 to $4,050\;ergs/mm^2$ The UV-irradiated sperm were inseminated into eggs from recessive color strain (yellow) or heterozygous transgenic mud loach containing CAT gene. Cold shock at $2^{\circ}C$ for 60 min, 5 min post fertilization successfully restored the diploidy of eggs inseminated with UV-irradiated sperm. Restoration to diploidy was confirmed by flow cytometry and gynogenetic status was verified by examining maternal exclusive inheritance of multi-locus DNA fingerprints, body color and transgenic marker. Putative isogenic transgenic fish clearly showed homozygous status at trans gene locus based on Southern blot hybridization and progeny testing. Further, such homozygous gynogenetic diploids revealed the increased levels of transgene expression, when compared to those of heterozygous (hemizygous) transgenic fish.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.61-66
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• 1998

The fish fauna and community structure were surveyed at the Naerin Stream of Puk'an River from June 1996 to September 1997. The fishes collected were 36 species, 28 genera belonging to 10 families, in which 16 species were endemic species of Korea. Oncorhynchus mykiss was an exotic fish. The dominant species was Zacco temmincki(relative abundance 42.94%), and subdominant species was Moroco kumgangensis(12.91%). The rare species less than 0.03% of all were Opsariichthys bidens, Squalidus japonicus coreanus, Misgurnus mizolepis, Leiocassis ussuriensis and Siniperca scherzeri. The species diversity, evenness, and dominance index on the fish community were 0.947, 0.609, and 0.218.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.247-260
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• 1992

This study was carried out to investigate the histomorphological changes of ovaries obtained from 100 of 1-year-old female Korean loach(misgurnus anguillicaudatus). The light microscopic and ultrastructural changes ofooplasm and follicular membranes of oocytes, were observed by lightand transmission electron microscope during the reproductive cycle. All data were collected from November in 1991 to May in 1992. The results obtained in this study were as follows: The size of the nucleoli and number of the yolk granules increased as the oocytes grown. Yolk granules were loosely deposited in the oocytes as crystalline granules. Due to the presence of large early and late maturing oocytes, their ovaries were enlarged, transparent, granular and yellowish in color. The lattice was broken down at hydration, leaving the egg transparent. As the percentages of fish in LMO and RO stage increased from March to April, mean gonadosomatic index(GSI) values(18.49%) increased. Zona radiata change a squamous into cuboid shape in EMO stage. Processes from the granulosa cells and from the oocyte, microvilli grow and make contact with other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radiata becomes more compact and devoid of pore canals during oocyte maturation. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in both GSI and macroscopic appearance.

• The Korean Journal of Zoology
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• v.37 no.3
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• pp.452-465
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• 1994

미꾸리속의 미꾸리(Misgumus anguillicaudatus)와 미꾸라지(M. mizolepis)의 종내 및 종간 유전적 변이와 유전적 차이를 알아보고자 2종 15개집단과 대만산 Paramisgumus김늠bwanus 1개 집단을 대상으로 전기영동법의 의한 동위효소분석을 실시한 결과 각. ongui각caudotus 9개 집단의 평균 유전적 변이정도는 P=34.20%, Ho=0.099, He=0 114였고. M. mizolepgs 6개 집단은 평균 P=35.55%, Ho=0 141, He=0.148이었으며, p연abwonus는 P=45.9%, Ho=0.132. 연e=0.119로서 일반적인 담수어류에 비해 높은 변이를 나타내었다 종간 평균 유전적 근연치를 비교한 결과 M. aneuflISca udatuo와 M. mfzole부랍 사이는 5=0.467이었고. M. angu연흘audatus와 P. dabrvanus 사이는 5=0.475로 비교적 근연관계가 낮았으나 M. mizolep결와 P. dabwanuo 사이는 5=0.834로 매우 가까운 유연관계를 나타냈다 유전적 차이치를 토대로 M. ongu비상라udctus와 M. mfzolep결의 종분화 연대를 산출한 결과 이들은 약 350만년전에 분화된 것으로 추정되었다.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.157-164
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• 1992

This stduy was carried out to obtain basic information available on ovulation, spawning, fertilization rate, hatching rate, and deformity rate after hCG injection in cyprinid loach, Misgurnus mizolepis. The results obtained in these experiments were as follows: 1. Ovulation and spawning occurred simultaneously and spawing was completed within 1 hour after ovulation. 2. More than 80% of fertilization rates appeared within 12 hours at 21$^{\circ}C$, 8 hours at $25^{\circ}C$, and 4 hours at 29$^{\circ}C$, respectively, following the onset of spawing. Afterwards, the fertilization rates of released eggs sharply decreased in three different water temperatures. 3. More than 70% of hatching rates appeared within 8 hours at 21$^{\circ}C$, 6 hours at $25^{\circ}C$, and 2 hours at 29$^{\circ}C$, respectively, following the onset of spawing. Afterwards, hatching rates of spawned eggs abruptly decreased in three different water temperatures. 4. The deformity rates of hatched larvae were high at $25^{\circ}C$, 8 hours following the onset of spawing. 5. Based on the developmental ability of oocytes, the optimum time of fertilization was 4 hours (stage 5) following the onset of spawing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.23-29
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• 2022

This study was carried out to clarify the egg, larvae and juveniles development of Misgurnus anguillicaudatus, and relationships of M. anguillicaudatus and M. mizolepis, Cobitididae Fishes. The adult fishes were collected in Samsan-cheon, Haenam-gun, Jeollanam-do, Korea and their spawning inducement was carried by ovaprim injections. The egg shape was circular and the size was average 1.12 mm. The eggs were hatched at 61 to 72 h after fertilization. The newly hatched larvae had an average 3.23 mm in total length (TL). At 5 days after hatching, the larvae reached to post larval stage and they were 10.3 mm in TL. At 19 days after hatching, it reached to juvenile stage and was 25.3 mm in TL. The egg size of M. anguillicaudatus was almost same as M. mizolepis but the hatching period of M. anguillicaudatus has taken longer. It was possible for interspecific distinguishability of M. anguillicaudatus and M. mizolepis when their larvae reached to juvenile stage by the development of keel-like ridges.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.69-77
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• 2012

To evaluate the effect of endocrine disruption chemicals (EDCs) to aquatic organisms, muddy loach (Misgurnus anguillicaudatus) was exposed to low concentration methomyl for 21 days in order to identify the effect of biomarkers and endocrine. Vitellogenin (VTG) in blood plasma, which used widely as validated biomarker for endocrine disruption, was significantly greater in male fish exposed to 0.4 mg/L and 2 mg/L methomyl, and in female fish exposed to 0.08 mg/L, 0.4 mg/L, and 2 mg/L methomyl for 21 days (p<0.05). This results suggest that methomyl have probability of endocrine disruption to organism on aquatic system. While inhibition of Acetylcholinesterase (AChE) activity and increase of DNA damage in comet assay were verified by fish exposed to methomyl, change of ethoxyresorufin-O-deethylase (EROD) activity was not occurred, comparing the control group (p<0.05). Indicators at the level of organism such as condition factor (CF), hepato-somatic index (HSI), and gonado-somatic index (GSI) were not influenced by exposure of methomyl. In conclusion, these results showed the possibility of methomyl in regard to not only endocrine disruption but also impacts on biochemical biomarkers to aquatic organisms.