• 한국수산과학회지
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• 제42권6호
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• pp.621-627
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• 2009

In order to standardize the juvenile abalone rearing technique, we selected sample farms by region in East, West and South coasts of Korea and Jeju island. We also have reviewed previous literature and visited farms to survey on the management of abalone juvenile production, spawning, hatching and so forth. Results of investigation are as follows: The light colors of tanks for larvae breeding are good for a frequent examination of larvae behaviour changes during the breeding period. The tank for the abalone juvenile production is a rectangular form in general and its size should amount to 3.5 m in length and 1.2 m width. It also should be built with proper drainage. The best age and size of adult for juvenile production are 3-6 years old individuals, with 9-12 cm separate burial and 125-150 g average weight. To induce spawning, the use of the exposure on air and ultraviolet ray together was the most effective. The density of larvae by plate should be 150-300 individuals and the proper stocking density was est imated and amount to 10-30 individuals. It has been shown that a correlation between water surface size($X_1$) and number of plates ($Y_1$), when producing abalone juveniles, is quite high and it is described by equation $Y_1=138.88X_1-5,736.8\;(R^2=0.9028)$. In addition, it has also been shown that a correlation between production of abalone juveniles ($Y_2$) and number of plates ($X_2$) is high and it is described by equation $Y_2=4.554X_2+12,493\;(R^2=0.8818)$. In Jindo region where a mass production of juveniles abalone has been done, it was shown, that a correlation between rearing water surface size ($X_3$) and production of juveniles abalone ($Y_3$) is very high and this relationship was described by the equation $Y_3=747.03X_2+94,359(R^2=0.9809)$. It has also been shown that a correlation between water surface size ($X_4$) and production of abalone juveniles ($Y_4$) in nationwide is high and the relationship between this variables was described by equation $Y_4=635.85X_4+99,923\;(R^2=0.9020)$.

• Journal of Ecology and Environment
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• 제31권4호
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• pp.333-339
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• 2008

We investigated death rates, growth rates and recruitment of culms in two neighboring bamboo (Phyllostachys bamboosoides) stands nested in by two different bird species to analyze stand structure and to design conservation strategies. A third bamboo grove not used by birds, the Taewha stand, was included as a control stand. The bamboo stand occupied by birds in the family Ardeidae (the Ardeidae stand) had an approximately 1.5 times higher culm density than the stand occupied by birds in the family Corvidae (the Corvidae stand). The crude death rate and the number of newly emerged shoots were also higher in the Ardeidae stand than the Corvidae stand. The death rate for bamboo in the Ardeidae stand was not dependent on diameter at breast height (DBH) and was almost 40% for culms of all sizes, whereas most dead culms in the Corvidae stand were < 4 cm DBH. Consequently, we conclude that in the Ardeidae stand, density-independent causes of death are operating, while density-dependent factor are more important in the Corvidae site. The results of soil analysis in these stands suggest that the density-independent death pattern observed in the Ardeidae stand may be due to soil acidification resulting from wastes produced by the birds during breeding. On the other hand, the culm distribution and death patterns in the Corvidae stand suggest that the stand characteristics were not affected by the nesting birds. These results suggest that different conservation strategies must be applied to conserve bamboo groves used by ardeids and corvids for nesting.

• Animal Bioscience
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• 제37권5호
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• pp.952-961
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• 2024

Objective: Stocking density (SD) is an important issue in the poultry industry, which is related to the production performance, intestinal health and immune status. In the present study, the effects of SD on the metabolism and homeostasis of uric acid as well as the related functions of the liver and kidney in ducks were examined. Methods: A total of 360 healthy 56-day-old Shan-ma ducks were randomly divided into the low stocking density (n = 60, density = 5 birds/m²), medium stocking density (n = 120, density = 10 birds/m²) and high stocking density groups (HSD; n = 180, density = 15 birds/m²). Samples were collected in the 3rd, 6th, and 9th weeks of the experiment for analysis. Results: The serum levels of uric acid, lipopolysaccharide and inflammatory cytokines (interleukin-1β [IL-1β], IL-8, and tumor necrosis factor-α [TNF-α]) were increased significantly in the HSD group. Serious histopathological lesions could be seen in both the livers and kidneys in the HSD group in the 9th week. The mRNA expression levels of inflammatory cytokines (IL-8 and TNF-α) and related pathway components (toll-like receptor 4, myeloid differentiation primary response gene 88, and nuclear factor-κB) were increased significantly in both the livers and kidneys in the HSD group. The mRNA expression levels of enzymes (adenosine deaminase, xanthine oxidase, phosphoribosyl pyrophosphate amidotransferase, and phosphoribosyl pyrophosphate synthetase 1) related to the synthesis of uric acid increased significantly in the livers in the HSD group. However, the mRNA expression level of solute carrier family 2 member 9, which plays an important role in the excretion of uric acid by the kidney, was decreased significantly in the kidneys in the HSD group. Conclusion: These results indicated that a higher SD could cause tissue inflammatory lesions in the liver and kidney and subsequently affect the metabolism and homeostasis of uric acid, and is helpful for guiding decisions related to the breeding and production of ducks.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.881-891
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• 2003

Paenibacillus polymyxa is a plant growth-promoting rhizobacterium (PGPR) which can be used for biological control of plant diseases. Several bacterial strains were isolated from rotten roots of Korean ginseng (Panax ginseng C. A. Meyer) that were in storage. These strains were identified as P. polymyxa, based on a RAPD analysis using a P. polymyxa-specific primer, cultural and physiological characteristics, an analysis utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME), and the 16S rDNA sequence analysis. These strains were found to cause the rot in stored ginseng roots. Twenty-six P. polymyxa strains, including twenty GBR strains, were phylogenetically classified into two groups according to the ERIC and BOX-PCR analyses and 16S rDNA sequencing, and the resulting groupings systematized to the degrees of virulence of each strain in causing root rot. In particular, highly virulent GBR strains clustered together, and this group may be considered as subspecies or biovar. The virulence of the strains seemed to be related to their starch hydrolysis enzyme activity, but not their cellulase or hemicellulase activity, since strains with reduced or no starch-hydrolytic activity showed little or no virulence. Artificial inoculation of the highly virulent strain GBR-1 onto the root surfaces of Korean ginseng resulted in small brown lesions which were sunken and confined to the outer portion of the root. Ginseng root discs inoculated in vitro or two-year-old roots grown in soil drenched with the inoculum developed significant rot only when the inoculum density was $10^{6}-10^{7}$ or more colony-forming units (CFU) per ml. These results suggest that P. polymyxa might induce ginseng root rot if their population levels are high. Based on these results, it is recommended that the concentration of P. polymyxa should be monitored, when it is used as a biocontrol agent of ginseng, especially in the treatment of stored roots.

• 환경정책연구
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• 제7권3호
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• pp.141-160
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• 2008

본 연구는 속리산 국립공원에서 쌍곡계곡 지역과 법주사 지역 내에 위치한 지역 중에서 인간의 의한 교란이 가장 큰 도로개설지역, 교란이 중간 정도인 등산로지역 그리고 간섭이 거의 없는 출입통제지역을 선택하여 산림생태계에서 인간의 교란 정도에 따른 조류군집의 차이를 연구하였다. 번식기와 비번식기의 조사(n=12)에서 조류의 종수와 개체수, 종다양도 및 밀도에서는 세 지역 사이에 유의적인 차이가 나타나지 않았다. 그러나 번식기의 조사(n=9)에서는 조류의 종수(Kruskal Wallis, $x^2$=10.32, p=0.006)와 개체수(Kruskal Wallis, $x^2$=7.118, p=0.028) 및 종다양도(Kruskal Wallis, $x^2$=9.847, p=0.007)가 인간에 의한 교란이 중간정도인 등산로 지역에서 가장 높게 나타났다. 그러나 번식기 조류 군집의 영소 및 취식 길드 분석에서는 세 지역 사이에 영소 및 취식 길드 분포비율은 차이가 나타나지 않았다. 영소길드는 세 지역 모두 나무구멍 영소길드가 가장 높았고, 취식길드는 수관층 취식길드가 가장 높게 나타났다.

• Journal of the Korean Data and Information Science Society
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• 제26권6호
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• pp.1249-1258
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• 2015

젖소의 유생산 형질에 가장 큰 영향을 미치는 유전자들 중 하나로 알려진 DGAT1 유전자의 효과를 국내 젖소 종축의 고밀도 유전체 정보를 이용하여 검증하기 위하여 본 연구를 수행하였다. 국내 젖소 씨수소로 구성된 353두의 고밀도 유전체 정보, 혈통, 추정 육종가 및 신뢰도 정보를 수집하였으며, 단일염기다형성 효과를 추정하기 위한 종속변량으로 가장 정확한 유전체 육종가를 예측할 수 있는 DeRegressed EBV를 산출하여 분석에 이용하였다. BovineSNP50 v2 패널을 이용하여 구명한 고밀도 유전자형 정보 중 유효성검증 과정을 통하여 41,051개 SNP을 선정하였으며, 각 단일 염기다형성의 실제적 유전체 육종가 기여도를 확인하기 위하여 유전체 선발방법 중 하나인 베이즈B (pi=0.99) 방법을 이용하여 SNP 효과를 추정하였다. 1메가 베이스페어의 구간으로 구성된 유전체 전장의 2,516개 윈도우 별 유전분산 설명력을 계산한 결과 상위 1, 3 윈도우가 DGAT1유전자 주변에서 발견되었으며, 이 두 윈도우의 유전분산 설명력은 각각 0.51% 및 0.48%인 것으로 나타났다. DGAT1유전자는 유전체 선발에 상업적으로 이용되는 50k SNP chip에 포함되어있지 않기 때문에 직접적인 유전자의 효과가 명확하게 드러나지는 않지만 DGAT1 유전자에 인접한 단일염기다형성들간의 연관불평형에 의하여 주변 윈도우에서 가장 높은 유전분산 설명력을 보이는 것으로 사료된다.

• 한국패류학회지
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• 제26권2호
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• pp.151-156
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• 2010

본 연구는 말백합 산업화를 위하여 어미성숙 관리한 인위성숙개체군과 시기별로 어미를 수송 채란한 자연성숙개체군을 산란유발 방법 별로 산란을 유도하여, 수정율, 부화율, D형 유생 발생률을 조사하였고, 유생사육 방법별로 유생의 성장과 생존율 등을 조사하였다. 인위성숙개체군의 간출시간별로 산란 유도한 결과 간출 4시간 및 8시간이 반응률이 23% 및 32%로 비교적 높았고, 수온 상승별로는 $28^{\circ}C$ 이상 되어야 반응이 시작되었다. 간출 및 수온상승 병행 시험구에서는 간출 4시간 및 $28^{\circ}C$에서 반응률이 45% 이상으로 나타났고, 29, 30, $31^{\circ}C$에서는 유의한 차이를 보이지 않아 말백합 어미는 간출시간보다는 수온상승에 반응률이 높은 것으로 나타났다. 어미수송개체군의 시기별 산란유발 결과는 2009년 8월 6일이 반응률 67.6%, D형 유생 발생률이 96%로 가장 높게 나타났다. 유생사육 시험 중 수온별로는 유생의 성장과 생존율을 고려할 때 유생사육 적정수온은 $27-31^{\circ}C$, 최적수온은 $29^{\circ}C$로 나타났고, 염분은 25에서 성장 및 생존율이 비교적 높았으며, 수용밀도별로는 5 inds./mL에서 성장 및 생존율이 비교적 높게 나타났음을 알 수 있었다.

• Molecules and Cells
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• 제20권2호
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• pp.201-209
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• 2005

We have constructed an AFLP-based linkage map of Japanese red pine (Pinus densiflora Siebold et Zucc.) using haploid DNA samples of 96 megagametophytes from a single maternal tree, selection clone Kyungbuk 4. Twenty-eight primer pairs generated a total of 5,780 AFLP fragments. Five hundreds and thirteen fragments were verified as genetic markers with two alleles by their Mendelian segregation. At the linkage criteria LOD 4.0 and maximum recombination fraction 0.25(${\theta}$), a total of 152 markers constituted 25 framework maps for 19 major linkage groups. The maps spanned a total length of 2,341 cM with an average framework marker spacing of 18.4 cM. The estimated genome size was 2,662 cM. With an assumption of equal marker density, 82.2% of the estimated genome would be within 10 cM of one of the 230 linked markers, and 68.1% would be within 10 cM of one of the 152 framework markers. We evaluated map completeness in terms of LOD value, marker density, genome length, and map coverage. The resulting map will provide crucial information for future genomic studies of the Japanese red pine, in particular for QTL mapping of economically important breeding target traits.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.35-41
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• 2023

Background: Several species of amphibians in agricultural areas are often infected with ranaviruses; however, the biological or ecological factors that cause this infection are not well understood. In this study, we investigated whether local tadpole density, Gosner developmental stage, and weather conditions affected ranavirus infection in Dryophytes japonicus tadpoles in rice paddies over three months. Results: During the study, eight samplings were undertaken between June 6 and August 21, 2022. No die-off of tadpoles occurred, but 20 of 110 tadpoles (18.8%) were found to be infected with ranavirus. The tadpole density at the sampling site and Gosner stage of the sampled tadpoles were not related to the daily ranavirus infection rate. The mean daily highest temperature during the two weeks prior to the sampling date and the mean daily lowest and highest temperatures during the week prior to the sampling date were negatively related to the daily infection rate. Conclusions: Our results suggest that low and extreme temperatures caused by flooding and draining of paddy fields or climate change in summer could be a significant risk factor for ranavirus infection in summer-breeding frogs in agricultural areas.

• The Korean Journal of Ecology
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• 제20권6호
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• pp.405-411
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• 1997

Feeding behavior of the Russet Sparrow Passer rutilans was studied in two different types of habitats, shelter belts and isolated forests, in south-eastern Hokkaido, Japan, during the breeding seasons of 1995 and 1996. Predominant foods were determined as Caterpillar, Coleoptera, Diptera, Ephemeropera, Odonate and some other insects. The composition of the nestiling foods were not the same by season, region, and year. Larger foods in size were used by birds in isolated forests more frequently than in shelter belts. Amount of food per feeding was significantly larger in isolated forests than in shelter belts. Although food supply were more abundant in isolated forests than in shelter belts, the feeding frequency did not significantly differ between these two habitats. The nest density was higher in isolated forests than in shelter belts. Results of this study indicate that when the feeding condition is poor, birds tend not show specific food selection behavior, the feeding range is therefore larger, and the feeding interval is longer. Contrarily, the birds show a specific food selection behavior when they are in good feeding condition, the feeding range is therefor smaller and the feeding interval decreases.