• Journal of The Korean Association For Science Education
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• v.23 no.2
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• pp.190-199
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• 2003

The purposes of this study was to investigate the effect of inductive Instructional method and deductive one concerning the learners' population genetic concepts and achievement according to learners' cognitive characteristics. For the study, 180 students were sampled from a boys' high school: 90 students for inductive teaching method and 90 students for deductive teaching method. Group Assessment of Logical Thinking(GALT) and Group Embedded Figure Test (GEFT) were used as the measure of cognitive characteristics. The results of this study were as follows. 1) The inductive instructional method was more effective in the understanding of population genetic concepts and their achievement. 2) Inductive instructional method was more effective than deductive one for the learners in formal operational level and in field independent cognitive style. 3) For the learners in a transitional level and field dependent cognitive style, deductive instructional way was more effective than inductive way on the average, but it was not statistically significant. It was turned out that learners' cognitive level was one of important factors when teachers instruct the concept of population genetics.

• Journal of Aquaculture
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• v.13 no.4
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• pp.325-330
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• 2000

For development of all male seed production at hatchery scale, a comparative study was made on the seed production traits of supermale (IT - t) and superfemale (IT - L1 ~) Nile tilapia, Oreochromis niloticus. Supermales were crossed with normal females (XX- f) and the superfemales with normal males (XY - t ) or sex reversed males (XX- L1 t); progeny survival of these crossings and sex ratio were evaluated. Hatching success of the eggs, fertilized by the supermale was significantly lower than that by the normal male. Over 95-99 % progenies sired by crossing supermales with normal females were males, while 52-55 % progenies alone were males with the cross of normal males and normal females. Hatching success and survival of alevins were significantly higher for the progenies of the crosses between superfemales and sex reversed males than those resulting from the crosses between superfemales and normal males. However, there was no significant difference in the sex ratio among the progenies of these crosses. Therefore, crossings of superfemales with sex reversed males provide the highest percentage of survival and male progenies.

• Journal of Aquaculture
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• v.20 no.3
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• pp.184-189
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• 2007

Treatment conditions for the induced diploid gynogenesis, a maternal-exclusive form of artificial parthenogenetic reproduction, were optimized in bagrid catfish (Leiocassis ussuriensis, Siluriformes). Optimal amounts of ultraviolet (UV) irradiation for the genetic inactivation of spermatozoa in bagrid catfish and Pseudobagrus fulvidraco were proven to be ranged from 3,600 to 4,800 $ergs/mm^2$ based on the examination of viability of embryos and haploid incidence. Haploid embryos were restored to diploidy by preventing the extrusion of the second polar body using cold shock treatment. Thermal treatments (4 or $6^{\circ}C$ for 30, 40 or 50 min) were carried out 3, 5 or 7 min post insemination. Best scores for embryo viability (38.6% of total eggs taken) and incidence of normal diploidy (87.9% of hatched larvae) were observed at the embryo group treated at $4^{\circ}C$ for 40 min, 5 min after insemination. Restoration of gynogenetic diploidy was confirmed based on the absence of haploid syndrome, cell size and/or nucleolar organizing region (NOR) counts.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.30-30
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• 2003

자성발생(gynogenesis)은 대상 어류의 성 결정기작이 암컷 동형접합성(female homogamety)인 경우 전 암컷 단성집단을 생산할 수 있으며, 단기간 내에 우수한 품종의 순계 획득과 유전적으로 동일한 clone 집단을 만들 수 있다(Thorgaard, 1986; 정 등 1996). 이에 제 1 난할 억제에 의한 메기 S. asotus에서의 체세포분열 억제성(mitotic) 자성발생 2배체가 유도된 바 있다(임 등, 2002), 염색체공학 기법 중 웅성발생 2배체(androgentic diploid)는 난자 핵을 불활성 시킨 후 정자 핵에 의해 제 1 난할억제에 의한 유전자 배가로 유도 될 수 있다. 본 연구는 염색체공학에 의한 메기 4배체 생산, 메기체세포분열 억제성 자성발생성 2배체의 효과적인 유도 조건 검정 및 메기 웅성발생성 2배체 생산을 위한 연구의 일환으로, 메기에서의 핵분열(korykinesis)에 관하여 조사하였다. 메기에서의 핵분열 수온 25$\pm$0.5$^{\circ}C$ 조건에서 수정 후 31분에 가장 현저하였다. 본 연구 결과를 Park and Im (2001)의 수온 24$^{\circ}C$에서의 제 1 난할 후기가 50분이며 mitotic interval이 18.5$\pm$1.2분인 결과와 비교시, 본 연구 결과의 수온 24$\pm$0.5$^{\circ}C$ 조건에서 핵분열이 수정 후 31분인 것은 핵분열과 세포질분열(cytokinesis)이라는 관점에서 정확히 일치한다. 염색체 수의 배가시, 핵분열 억제는 세포질 분열 억제에 비해 더욱 효과적으로서(Cherfas et al., 1993; Nam et al., 1999), 본 연구 결과의 핵분열 시간(수온 24$^{\circ}C$ 조건에서의 수정후 31분)을 기반으로 하여 차후, 4배체 메기와 체세포분열 억제성 자성발생 2배체 메기 및 웅성발생성 2배체 메기 유도 및 그의 생산성 향상에 관한 연구가 기대된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.69-76
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• 1995

Cold acclimation involves changes in gene expression. BN28 and BN115 are two genes which are regulated by cold temperature and assumed having roles in cold acclimation. The objectives of this experiment was to explore the expression of BN28 and BN115 under field conditions. Six winter cultivars were planted at three different dates during the fall. The expression of the genes was determined by northern blot analysis of total RNA taken from leaves 15 to 30 day-intervals after planting. The expression of the two genes was detected within 15 days after planting well before onset of freezing tolerance in plants. This suggestes either their expression was a prerequisite of the freezing tolerance or their expression was regulated by other environmental factors as well as temperature. Two genes showed a different expression pattern suggesting they had a different regulatory system. Although timecourse increase in expression of the cold-regulated genes was matched with increase in freezing tolerance, the difference of expression in cultivar level at specific times of measurement was not correlated with freezing tolerance at the moment.

• Korean journal of communication and information
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• v.32
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• pp.7-48
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• 2006

The study explores how Korea's major newspaper cover about science news, especially how newspaper frame biotechnology news including new source, news construction ways, coverage trend. The research has a research design to find out coverage pattern or model with frame theory. The result shows that the newspaper has some aspect of frame through out the biotechnology development in the section, theme, source, complexity. The section has been expend to the society and international section, while the theme shift from disease or cancer cure to life itself, genome, or stem cell. In the complexity, the biotechnology news stories have been developed a story plot (event-problem-development-solution). In the climax, the news coverage focuses on the explanation of biotechnology news.

• Journal of Aquaculture
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• v.17 no.3
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• pp.197-208
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• 2004

Five commercially valuable Korean Veneroid, Protothaca jedoensis, Ruditapes philippinarum, Saxidomus purpuratus, Cyclina sinensis and Meretrix lusoria were recognized by comparing internal and external morphological characters. As length of the primary tooth was directly grown proportional to shell size but all other characters were not measured according to size of shell. Hence, the morphological characters of these Veneroids may be estimated from the size of the unique primary tooth and it might be enough to be a good criterion for identification of species among Veneriods. Numerical index of hinge plate length of these species was assessed systematically, irrespective of measuring the length, height and width of the shell. The highest internal and external morphological similarity was observed between P. jedoensis and R. philippinarum and the lowest similarity was observed between P. jedoensis and M. lusoria. These similarities may be affected by multiple environmental factors as well as genetic characters. For artificial seed production of P. jedoensis, R. philppinarum, a closest relative among the five species, must be focussed.

• Journal of Aquaculture
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• v.19 no.2
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• pp.67-76
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• 2006

Genomic DNA isolated from two Porphyra species, P. tenera and P. dentate from Wando located on the southern coast of Korean peninsula was amplified by PCR reaction. The amplified products were separated by agarose gel electrophoresis (AGE) with decamer primer and stained with ethidium bromide. The eight arbitrarily selected primers OPA-04, OPA-06, OPB-01, OPB-08, OPB-10, OPB-11, OPB-14 and OPC-10 generated the shared loci, polymorphic, and specific loci. The size of DNA bands varies from 100 bp to 2,200 bp. The complexity of the banding patterns varies dramatically between the primers and two Porphyra species. A total of 528 loci observed were identified in P. tenera and 443 in P. dentata: 22 polymorphic loci (4.2%) in P. tenera and 30 (6.8%) in P. dentata. 154 shared loci observed, the average 19.3 per primer, were identified in P. tenera and 143 loci, the aver-age 17.9 per primer, in P. dentata species. The number of specific loci in P. tenera and P. dentata was 73 and 77, respectively. The average bandsharing value was $0.623{\pm}0.008$ with P. tenera and $0.560{\pm}0.009$ within P. dentata. The average bandsharing value between two Porphyra species was $0.408{\pm}0.004$, ranged from 0.305 to 0.564. The dendrogram obtained by the eight primers indicates four genetic clusters. The genetic distance between two Porphyra species ranged from 0.076 to 0.627. The individual no. 02 of P. tenera was genetically closely related to no. 01 of P. tenera(genetic distance=0.082). Especially, two entities between the individual DENTATA no.21 and DENTATA no. 19 of P. dentata showed the longest genetic distance (0.627) in comparison with other individuals used. In this study, RAPD-PCR analysis has revealed the significant genetic distance between two Porphyra species pairs (P<0.001).

• Journal of Aquaculture
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• v.10 no.3
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• pp.301-310
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• 1997

To investigate a possibility of the species genetic relationship for the soluble proteins analysis on the class Cephalopoda in the Yellow Sea, the isolate eye, muscle and liver proteins from five species (Sepia esculenta, Sepiella japonica, Loligo chinensis, Loligo beka and Octopus minor) were analysed using different electrophoretic techniques (Davis-polyacrylamide gel electrophoresis, SDS-PAGE, exponential gradient SDS-PAGE, thin-layer isoelectro-focusing and two-dimensional PAGE). The average molecular weight of the soluble eye and muscle proteins was estimated at 35-50 KDa, separated b the exponential gradient SDS-PAGE. It was corresponds to that of electrophoretic patterns by t재 dimensional PAGE. By which the thin layer IEF, the target proteins showed a reasonable specificity based on their isoelectric points (pI) 7.5-8.5.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.3
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• pp.163-169
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• 2006

In the survey of the samples infected by iridovirus, we found the natural outbreak of iridovirus disease in the ornamental fish, pearl gourami (Trichogaster leeri) in Korea. It was characterized by the appearance of enlarged cells and necrosis in the observation of the imprinted spleen cells under iridovirus. To determine the infection of iridovirus more accurately, PCR using 2 different primer sets for MCP and ATPase gene used for the diagnosis of iridovirus infection was done and found the produced fragments matched with the size of expectation. Partially determined nucleotide sequences of the MCP gene of the iridovirus isolated in this study showed very high homology (99.6%) with that of ISKNV as a reference strain. In challenge experiment with the iridovirus isolated from the moribund of pearl gourami, the pathogenicity of the isolated iridovirus was confirmed and suggested the potential of the risk associated the transfer of iridovirus from the ornamental fishes to the marine culturing fishes.