• 한국양봉학회지
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• 제34권1호
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• pp.1-6
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• 2019

프로폴리스는 꿀벌이 식물로부터 수집해 오는 수지성분으로 질병이나 기타 환경적인 요인으로부터 봉군을 보호하는 기능을 가지고 있다. 꿀벌 계통의 프로폴리스 생산성은 봉군의 유전적인 특성에 의해 결정된다. 본 연구에서는 프로폴리스 생산성 우수 계통 선발을 위한 연구의 일환으로 국내 수집 꿀벌 계통에 의한 프로폴리스 생산성을 평가하고 특성이 우수한 계통을 유지·보존하고자 하였다. 지역별 수집 계통 P1, P2, P3의 프로폴리스 생산성 평가는 2017년 6~7월, 8~9월 2차례에 걸쳐 이루어졌으며, 그 결과 P2 계통의 프로폴리스 생산성이 각각 10.1 g/hive, 4.25 g/hive로 가장 우수한 것으로 확인되었다. 이들 계통에 대한 봉군발육조사 결과 P2 계통의 일벌 개체수가 타 계통에 비해 월등히 높아 이 계통의 프로폴리스 생산성에 크게 기여했을 것으로 보고 있다. 이러한 결과를 통해 본 연구에서는 국내 수집 서양종꿀벌 원종 계통 중 프로폴리스 생산성이 가장 우수한 계통은 P2 계통인 것으로 평가되었으며, 향후 프로폴리스 생산성 우수 계통 선발을 위한 기초 자료로 제공될 수 있을 것이라 기대하고 있다.

• 한국양식학회지
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• 제22권1호
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• pp.92-99
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• 2009

대하새우 양식장에 서식하는 곤쟁이 Neomysis japonica (Ishikawa and Oshima, 1951)의 개체군 역학과 성 성숙에 관한 전반적인 생물학적 정보를 밝히기 위해 2002년 10월부터 2003년 9월까지 12개월 동안 매월 1회씩 충남 태안군 남면 당암리에 소재한 순천향대학교 해양수산연구소의 대하새우 양식장에서 표본을 채집하였다. 개체군의 특성을 알기 위해 성비, 성 성숙도, 포란수 그리고 성장계수 등을 조사하였다. 암컷이 수컷에 비해 월별 성비가 높았고, 평균 갑각장은 수컷($2.42\;mm{\pm}0.52$)이 암컷($2.31\;mm{\pm}0.48$)보다 높았으나 모두 오차 범위내에서 차이를 보여 갑각장의 크기는 통계학적으로 유의하지는 않았다. 암컷은 성체의 크기가 큰 개체가 많은 난을 포란하였으며, 암컷의 50%가 포란하는 체장은 4.48 mm였다. von Bertalanffy, 성장 매개변수를 바탕으로 한 계절별 성장 속도는 암컷이 수컷보다 빨랐으며, 양식장내에 서식하는 개체군은 일년 중 2회의 가입을 하는 것으로 나타났다. 암컷과 숫컷의 상대성장을 회귀직선 방식으로 비교한 결과수컷의 성장속도가 암컷보다 조금 빨랐다.

• 한국수산과학회지
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• 제36권2호
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• pp.144-150
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• 2003

Reproductive biology and population dynamics of Latreutes planirostris were investigated on the south western waters of Korea from June 2001 to May 2002. This paper describes sex ratio, population growth, and reproductive aspects of Latreutes planirostris. Brood size was an isometric function of female carapace length. Based on dry weight, reproduction effort (mass of eggs/mass of female) averaged 0.23. Ovarian examination showed that there was significantly higher gonadosomatic index from May to September, with a peak in June. Statistical analysis revealed that the ovarian dry weight of females with eyed eggs was significantly higher than that of those with non-eyed eggs. This suggests that females were potentially consecutive breeders. Sex ratio showed that female is more numerous than male. Growth parameters mortality and recruitment were estimated by monthly length-frequency data. Growth parameters were estimated, using the seasonalized von Bertalanffy growth function model $(L\infty\;=\;12.70\;mm\;CL,\;K\;=\;0.87yr^{-1},\;C\;=\;0.96,\;WP\;=\;0.59)$. The recruitment pattern was twice a year.

• Fisheries and Aquatic Sciences
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• 제13권4호
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• pp.308-314
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• 2010

Larvae of Palaemon serrifer were reared in the laboratory under three different temperature regimes ($15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$) to study the effects of rearing temperature on larval survival and growth, as well as other traits such as embryo volume, number of embryos (fecundity), incubation period, development. Mode and development period. Growth pattern was analyzed by measuring the molt increment and intermolt period. The intermolt period consistently increased with size and instar number and was shortest at $25^{\circ}C$. However, molt increments generally decreased with instar number. Number of embryos varied from 552 to 1355. The relationship between the number of embryos and carapace length was expressed by the equation (fecundity) y=2.7744x+0.208 ($R^2$=0.7961). Egg volume was a primary factor affecting other life-history traits. Egg volume was $0.078\;m^3$, which is relatively small thus embryos exhibited a relatively short incubation period and a comparatively short development period, and the nutritional mode was planktotrophic. Brood production was followed by a fast parturitional pattern. Most ovigerous females had mature ovaries when the parturial molt occurred soon after eclosion.

• 생명과학회지
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• 제9권5호
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• pp.518-524
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• 1999

Timing of oviposition, nuclear maturation of oocytes, egg-sperm contact and brooding were observed in the giant fresh-water prawn Macrobrachium rosenbergii reared in the laboratory. When a pre-spawning molted female was transferred to the male, the female oviposited commonly at 5 to 10 hr after mating. The first polar body were extruded within 2-3 min after spawning. The egg chromosome progressed to release second polar body by 30 min and mitotic nuclear division occurred in 8 hr after spawning. Thumbtack-shaped spermatozoa were seen peneterating egg membrane with their spike directed forward. Transformation of spermatozoa and fertilization membrane could not be observed by light microscopy. The elapsed hours from oviposition to the end of brooding wee taken in 5-7 hr. Brood size for female 9 cm and 18 cm in body length was estimated to be 10,000~15,000 and 100,000 eggs, respectively and is proportional to the total length of the berried females. The ovigerous females reared at chlorinity of 2.21~4.25$\textperthousand$Cl. showed a normal egg development up to hatching.

• Molecules and Cells
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• 제19권1호
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• pp.149-154
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• 2005

Cyclic nucleotide-gated (CNG) channels encoded by the tax-4 and tax-2 genes are required for chemosensing and thermosensing in the nematode C. elegans. We identified a gene in the C. elegans genome, which we designated cng-1, that is highly homologous to tax-4. Partial CNG-1 protein tagged with green fluorescent protein was expressed in several sensory neurons of the amphid. We created a deletion mutant of cng-1, cng-1 (jh111), to investigate its in vivo function. The mutant worms had no detectable abnormalities in terms of their basic behavior or morphology. Whereas tax-4 and tax-2 mutants failed to respond to water-soluble or volatile chemical attractants, the cng-1 null mutant exhibited normal chemotaxis to such chemicals and a tax-4;cng-1 double mutant had a similar phenotype to tax-4 single mutants. Interestingly, cng-1 and tax-4 had a synergistic effect on brood size.

• 한국환경보건학회지
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• 제33권2호
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• pp.123-131
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• 2007

Many environmental contaminants including several metals, polycyclic aromatic hydrocarbons, and pharmaceuticals, have been identified to be phototoxic in the water environment. Concerns regarding photo-enhancement of toxicity of several environmental contaminants have been increasing because of the increased level of ultraviolet irradiation on the earth surface. However, there exist arguments that there might be certain defense mechanisms taking place in the aquatic ecosystem, which may include behavioral characteristics or genetic acclimation. This study was conducted to understand the potential responses of aquatic receptors to several phototoxic metals in the real environment, where long-term acclimation of such organisms to low dose UV-B may take place. For this purpose, water flea Daphnia magna was acclimated to environmentally relevant dose of UV-B (12 to $18uW/cm^2$) for >11 generations. The differences in developmental and life history characteristics, and toxicity responses were evaluated. Acclimation did not affect the daphnids' growth, longevity, and reproduction characteristics such as time to first brood, and brood size: After 21 d, survival of D. magna was not influenced by UV-B acclimation. When the number of young per female was compared. the daphnids acclimated for 11 generations tend to produce less number of neonates than the un-acclimated individuals but with no statistical significance (p>0.05). Four metals that were reported to be phototoxic elsewhere were employed in this evaluation, that include As, Cd. Cu, and Ni. UV-B level being applied in acclimation did increase the toxicity of Cd and Cu, significantly (p<0.05). However, the toxicities of As and Ni were not affected by irradiation of UV-B. Phototoxic responses were evaluated between the acclimated and the un-acclimated daphnids. For Cu, UV-B acclimation led to reduction of the photo-induced toxicity $(p\approx0.1)$ in daphnids. Non-acclimated Daphnia were affected by 50% at 4.18 ug/l Cu. but UV-B acclimated individuals exhibited $EC_{50}$ of 5.89 ug/l. With Cd, UV-B acclimation appeared to increase phototoxicity (p>0.05). With As and Ni, UV-B acclimation did not influence photo-induced toxicity. This observation may be in part explained by the type of reactive oxygen species that were generated by each metal. Similar to UV-B light, Cu is known to generate superoxide anion by acting as redox cycling toxicant. This is one of the first studies that employed_laboratory based UV-B acclimated test species for photoenhanced toxicity evaluation.

• The Korean Journal of Ecology
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• 제25권4호
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• pp.241-245
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• 2002

During the breeding season of 1998, breeding ecology of the Great Reed-Warbler (Acrocephalus arundinaceus orientalis) was studied at Yangsoo-ri and Yongdam-ri of the Yangpyung-gun, Kyunggi province, Korea. Egg-weight (CV: 6.25) was more variable than either length or breadth, and breadth was the least variable of the measures. Significant variations in overall egg-weight occurred between clutches, and that more of the total variation in egg-weight and shape are due to inter-clutch variation as to intra-clutch variation when the data were pooled. The last egg tends to be larger than the remaining eggs in the clutch of the Great Reed-Warbler, suggesting the Great Reed-Warbler may adopt the brood-survival strategy. When method 3 was used, the most common incubation period is 12 days. In the Great Reed-Warbler, the length of the incubation period was related to clutch-size when method 1 (r=0.485, p<0.05) and method 2 (r=0.621, p<0.01) were employed, but not related to egg weight. The averagee number of days of hatching asynchrony was 2.5, raging 0.5~2.5. Asynchronous hatching was related to the clutch size (r=0.66, p<0.01). Hatching sequence was closely related to the laying sequence (r=0.93, p<0.001), suggesting Great Reed-Warblers incubate their eggs before clutch completion. The effect of egg weight on hatching asynchrony was found in Great Reed-Warblers (t-test, p<0.01).

• 한국산림과학회지
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• 제100권3호
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• pp.397-401
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• 2011

본 연구는 활엽수림 지역에 설치한 인공새집에서 번식을 실시한 박새류의 번식 생태를 파악하기 위하여 2006년부터 2010년까지의 매년 3월부터 7월까지의 기간 동안 실시되었다. 5년에 걸친 조사기간 동안 활엽수림에 설치한 인공새집에서는 곤줄박이, 쇠박새, 박새 등의 박새류가 번식을 하였다. 박새류가 번식을 실시한 인공새집은 입구직경별로 번식쌍수가 큰 차이가 없는 것으로 나타났다. 종별로는 박새가 가장 많이 이용한 것으로 나타났으며, 곤줄박이가 가장 적게 이용하였다. 인공새집을 이용한 박새류는 몸의 크기에 따라 선호하는 입구직경이 달랐는데, 몸의 크기가 큰 박새는 입구직경이 35~40 mm인 인공새집을 주로 이용하였다. 반면 몸의 크기가 가장 작은 쇠박새는 입구직경이 30 mm인 인공새집에서 주로 번식을 하였다. 첫 산란일, 한배 산란수, 한배 새끼수, 포란기간, 육추기간, 번식성공률은 종별, 연도별로 차이를 보였다. 앞으로 박새류의 번식생태에 영향을 주는 요인에 대한 연구를 통해 환경요인과 번식생태에 관한 규명이 필요할 것으로 판단된다.

• Journal of Ecology and Environment
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• 제35권1호
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• pp.9-14
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• 2012

Yellow bitterns (Ixobrychus sinensis) are a small wetland bird common to Asian countries including South Korea, Japan, and China. The aim of this study is to describe diet of yellow bitterns during the breeding season in artificial wetland of northeastern South Korea between May to August 1999-2001. For the purposes of this paper, we observe the frequency of nest visiting by parents during the chick rearing period. A total of 98 boluses regurgitated by 52 chicks aged 1 day to 11 days after hatching form the sample and are shown to contain 323 food items. A bolus contained mean 3.8 items and weighs 0.2 g to 7.7 g. The most regularly occurring food items recorded are fish (63%) and insets (33%). In terms of fish, top mouth minnows (Pseudorasbora parva) and crucian carps (Carassius auratus) are frequently observed. In terms of insects, there are mosquitoes (Diptera), instars of dragonfly (Libelluidae), damselflies (Coenagrinonidae) and water bugs (Diplonychus japonicus). Yellow bitterns were also shown to feed on bull frogs (Rana catesbeiana), shrimp (Palaemonidae), and spiders (Araneae). The size of fish in a bolus ranged from 15.56 mm to 93.73 mm (mean, 37.08 mm). The amount of food can be observed to increase with the age of chicks (r = 0.279, P = 0.025, N = 64) but parents did not provide larger fish as chicks grew. Parent birds visited nests more frequently when they have a larger brood ($F_{1,21}$ = 14.529, P = 0.001). Our results suggest that fish is the most important prey during the breeding season and that age of chicks is related to amount of diet in yellow bitterns.