• The Korean Journal of Malacology
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• v.32 no.2
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1221-1225
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• 2005

The peroxisome proliferator-activated receptors (PPARs) are members of a superfamily of nuclear hormone receptors. Lots of studies in rodents and humans have shown that PPARs were involved in lipid metabolism and adipocyte differentiation. The main objective of this work was to detect the single nucleotide polymorphisms (SNPs) in whole coding regions of peroxisome proliferator-activated receptor alpha (PPAR-$\alpha$) and gamma (PPAR-$\gamma$) genes with approach of single strand conformation polymorphism (SSCP) in the chicken population of Arber Acres broiler, Hyline layer and three Chinese native breeds (Shiqiza, Beijing You, Bai'r). Two SNPs of C1029T and C297T were found in chicken PPAR-$\alpha$ and PPAR-$\gamma$ genes respectively and each SNP found three genotypes in the experimental populations. The results showed that the distribution frequency of 3 genotypes in Arber Acres broiler, Hyline layer and Chinese native breeds had significant differences on the PPAR-$\alpha$ and PPAR-$\gamma$ gene respectively (p<0.01). Furthermore, in the PPAR-$\alpha$ gene, the results of least square estimation for genotypes and body composition traits showed the BB genotype birds had higher abdominal fat weight (AFW) and percentage of abdominal fat (AFP) than AA genotype birds (p<0.05). From these we conjecture the PPAR-$\alpha$ and PPAR-$\gamma$ genes were suffered intensive selection during the long term commercial breeding and the PPAR-$\alpha$ gene may be a major gene or linked to the major genes that impact chicken fat metabolism and the SNPs could be used in molecular assistant selection (MAS) as a genetic marker for the chicken fatness traits.

• Ocean and Polar Research
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• v.23 no.4
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• pp.425-431
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• 2001

From an ecological point of view, the western part of the Atlantic sector is one of the most productive areas in the Southern Ocean. Antarctic krill (Euphausia superba) and krill-dependent predators such as fish, seals, and birds are abundant there, and most krill fisheries have operated in this area since 1970s. The hottest issues for the proper management of krill resources nowadays are to determine total biomass in this area, and to identify environmental forces controlling stock fluctuation. This paper reviews and collates information on ongoing oceanographic activities in the Antarctic Peninsula region concerning these issues. To delineate the status and function of Antarctic krill population in Antarctic marine ecosystems, multinational researches along the Antarctic Peninsula area have been developing recently. Four member states of CCAMLR (Japan, Russia, UK, and USA) had conducted acoustic surveys in January-February 2000 (socalled CCAMLR-2000 survey), and krill standing stock at 120 kHz was estimated to be 44.29 million metric tonnes in the western Atlantic sector of the Southern Ocean. On the other hand, the Southern Ocean GLOBEC (SO-GLOBEC) Programme has prepared a serial winter survey to examine the factors that govern krill survivorship and distribution in relation to shelf circulation processes. Ship-based surveys using ice-breakers are being conducted by three nations (Germany, UK, and USA) around the Marguerite Bay during the austral fall and winter 2001 and 2002. In addition to these two large-scale surveys, some CCAMLR members have carried out joint oceanographic surveys near the South Shetland Islands to detect ecosystem changes since 1994. Especially from December 1999 to February 2000, in conjunction with CCAMLR-2000 survey, four nations (Japan, Korea, Peru, and USA) conducted acoustic surveys to produce time-series information on krill distribution and biomass near the South Shetland areas. Though the aims of each program and the approach to solve the scientific questions were different each other, the results from each program fill the gaps between programs. Further cooperation and exchange in these activities could be beneficial to each program.

• Ocean and Polar Research
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• v.25 no.1
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• pp.21-30
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• 2003

Seasonal fluctuations of physico-chemical and biological aspects of the environment were studied in Vladivostok harbour (Golden Horn Bay, the East Sea/Sea of Japan). The benthic community structure was described with a focus on size-spectra (bacteria, meio- and macrofauna) related with the chemical environment and chemical fluxes in sediment and to reveal their possible ecological role in the process of bioremediation of the environment. Samples from two sites with different concentrations of heavy metals (Fe, Zn, Cu, Pb, Mn, Cr, Ni Cd, Co) and petroleum hydrocarbon were assessed by a number of methods. These included plate counts of culturable bacteria, observation through a scanning electron (SEM) and transmission electron microscope (TEM). These approaches were complemented with microscopic assessments of the diversity of the benthic community. The specific communities had a limited number of species, tolerant to abnormally high levels of toxic compounds. The dominant species were presented by several sho.1-lived small polychaetes (Capitella capitata) and nematodes (Oncholaimium ramosum). The highest population density was recorded in microbenthos, in various diatoms, various physiological groups of bacteria which participate in biomineralization: marine heterotrophic bacteria, which oxidized oil, black oil in addition to groups resistant to heavy metals. They have the entire set of mechanisms for neutralizing the negative effect of those compounds, forming the detrital food web and biogeochemical circulation of material in sediments, which results in the biological self-recycling of sea basins. Macro- and meiobenthic organisms were more sensitive to a greater extent of $H_2S$ and petroleum hydrocarbons than to metal content, but the within-site rankings were the same as those achieved for microbiological analyses.

• Proceedings of the Korean Nutrition Society Conference
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• 2002.06a
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• pp.598-603
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• 2002

While the sequencing of several genomes was underway, several advanced techniques in genetics, molecular biology and protein chemistry emerged. Within the notritional sciences, while the focus on nutrition education, epidemiology and public health aspects remains essential; it is crucial to incorporate the new advances in gene and protein discovery in nutritional studies. Nutrition is a discipline that has always integrated social, biochemical and physiological sciences from the studies at the molecule level to studies at the population level. for this reason, nutritionists are in a prime position to readily incorporate the current genomics approaches in nutrition research. All the available analytical techniques can and should be used in modem nutritional sciences. These include genetics, genomics, proteomics and metabolomics which also require integration and use of bioinformatics and computational methods for data analysis and management. These applications will be briefly reviewed with a primary focus on what the genomics and genetics approaches offer to nutritionists. We will use one of our research focus areas to illustrate uses of some of these applications in obesity-hypertension research. Our central hypothesis is that adipose tissue is an endocrine organ that plays a major role in obesity and related hypertension. We are primarily studying the renin angiotensin system (RAS). We provide evidence from our own studies and others for the paracrine as well as endocrine role of adipocyte-derived angiotensin II in adipocyte gene expression, adiposity and blood pressure regulation. Both cell culture studies as well as knockout and transgenic mice models are used to test our hypothesis. Genomics and proteomics technologies are currently developed to complement our physiological and molecular studies on the RAS and for a fine analysis of this system and its function in health and disease.

• The Korean Journal of Zoology
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• v.7 no.2
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• pp.41-47
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• 1964

D.auraria is a species belonging to the D.melanogaster group, and this species was divided into 3 races(A, B and C race ) by morphoogical difference of the genitals . Korean populations of D.auraria A race are polymorphic with respect to the pigmentation of the abdominal tergites. The female shows two forms of color pattern, dark and light, on the sixth to the ninth tergites, and the male has no distinction shown by the female. Crossing experiments in the laboratory have shown that the difference between these color forms is due to a single pair of allelic genes located on an autosome. In natural populations, the light forms of females are always commoner than the dark one. The number of the light form increases relatively in southern localities and decreases relatively in northern localities. Furthermore, the number of the light form increases relatively in summer and decreases relatively in fall and spring. By genetic analyses of these wild flies, the relation, d/d>d/D>D/D has been disclosed as regards the relative frequencies of the genotypes in natural populations. Three experimental populations have been set up in the laboratory. Homozygous dark forms and homozygous light forms were mixed together and cultured in population cage at the temperature of 25 $^{\circ}C$. Approximately one year later, the frequencies of the light and the dark forms reached an equilibrium , the light one being usually more frequent than the dark one. This indicates that the heterozygous dark form possesses the highest adaptive value, the homozygous light being intermediate and the homozygous dark lowest. In number of adults hached, the homozygous light form was superior to the heterozygous dark form and the homozygous dark form, but the differences are scarcely significant.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.201-206
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• 2013

Aporia crataegi, an Korean endangered species, was first analyzed for DNA barcode sequences based on 28-year-old dried specimens and compared barcode characters with 36 individuals of ten geographical populations of Eurasia. They were revealed to consist of five different haplotypes. Among them, haplotype I was mostly extensive and high frequency with 75%. The south Korean individuals were confirmed to be belonging to haplotype I and have no genetic isolation on COI gene. By these results, we consider that selection of the identical haplotype from other geographical populations may be a requirement prior to performing for conservation and restoration of the Korean population. We also propose to analyse the additional genetic markers in order to understand a more accurate genetic structures between haplotypes of this species.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.1
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• pp.51-57
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• 2017

The tiny dragonfly, Nannophya pygmaea (Odonata: Libellulidae), is an endangered insect in South Korea. Previously, a partial mitochondrial DNA sequence that corresponded to a DNA barcoding region has been used to infer genetic diversity and gene flow. In this study, we additionally sequenced the barcoding region from N. pygmaea that had been collected from three previously sampled populations (40 individuals) and these sequences were combined with the preexisting data. We also selected and sequenced an additional mitochondrial gene (ND5) to find further variable gene regions in the mitochondrial genome. DNA barcoding sequences of 108 individuals from five South Korean localities showed that genetic diversity was highest in Gangjin, Jeollanam-do Province. Muuido, which was previously occupied by a single haplotype, was also found to have an identical haplotype, which confirmed the low genetic diversity on this islet. Gene flow among populations is highly limited, and no clear distance- or region-based geographic partitioning was observed. Phylogenetic relationships among haplotypes showed that there were no discernable haplotypes in South Korea. ND5 provided slightly more haplotypes compared to the barcoding region in 40 individuals (14 vs. 10 haplotypes in the COI gene). It also had a slightly higher within-locality diversity estimate, which suggested that ND5 had potential as mitochondrial DNA-based marker for population genetic analysis.

• Animal Systematics, Evolution and Diversity
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• v.26 no.1
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• pp.15-19
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• 2010

The Russian ratsnake, Elaphe schrenckii, is found in Russia, China, and Korea, and is considered to be an endangered species by the Ministry of Environment in South Korea. Due to habitat loss and use in oriental medicine, their population has been severely decimated. In South Korea, two subspecies of E. schrenckii has been defined according to body color: E. s. schrenckii (blackish) and E. s. anomala (yellow-brownish). Molecular genetic studies on Elaphe schrenckii are very scarce and the taxonomy of Elaphe schrenckii subspecies is uncertain. From the present study, we attempted to identify the genetic differences of these two subspecies using species-specific microsatellites developed from the genomic library of E. schrenckii. Nine polymorphic loci were tested on 19 individuals from E. s. schrenckii (n=10) and E. s. anomala (n=9) in South Korea. The mean number of alleles was 3.78 in E. s. schrenckii and 4.11 in E. s. anomala. The average expected heterozygosity was 0.542 and 0.511 in E. s. schrenckii and E. s. anomala, respectively. We found a lack of genetic structure between two subspecies ($F_{ST}=0.016$) and no genetic discrimination between two subspecies was found. Based on the present findings by microsatellites, two subspecies can be considered as one species, E. schrenckii. However, further investigations on taxonomical status using mitochondrial and nuclear DNA sequences need to be performed and morphological & ecological data should be revised. The genetic markers should benefit future studies of the endangered species of other Elaphe species for the study of genetic diversity and potential conservation management.

• The Korean Journal of Malacology
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• v.25 no.1
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• pp.23-28
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• 2009

Samplings have been monthly collected in Jeju Island, Korea, using ser nets. A total of 759 individuals were sampled from June to November 2006. We analyzed mantle length distribution, monthly changes in maturity stages, maturation size and sex ratio. Mean Mantle length of the female specimens ranged from 6.7 to 50.3 cm and that of the male specimens ranged from 6.7 and 50.0 cm. The spawning period was November. The Mantle length at 50 % group maturity was estimated to be 17.1 cm. Sex ratio was 1 : 1.3 (male : female), suggesting the female population may be predominant.