• 한국식물병리학회지
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• 제3권2호
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• pp.131-136
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• 1987

벼 품종 Brazos와 M-201의 도열병에 대한 단위시간당 감염속도와 점접종원으로 부터의 단위 거리당 확산경사는 밭논과 물논의 두 재배조건에 따라 크게 달랐다. 물논재배는 도열병의 감염속도를 늦추고 확산경사를 완만하게 하였다. 점접종원으로부터 거리별로 4지점에서 측정된 도열병의 감염속도는 거리에 따른 통계적인 유의차는 없었지만 점접종원으로부터의 거리가 멀어짐에 따라 빨라지는 경향이었다. 품종별 감염속도는 Brazos보다 더 이병성인 M-201 품종에서 높았고 확산경사도 M-201 품종에서 가파른 경향이었다. 그러나 도열병이 진전함에 따라 생성된 이차전염원 때문에 도열병 확산경사는 두 품종에서 모두 완만해졌다. 조사된 확산형사의 두 경험적 모델 중에서 Kiyosawa와 Shiyomi 모델이 Gregory 모델에 비하여 통계적 적합성이 높았다. 밭상태에서 단위시간당 도열병 isopaths 이동거리는 Brazos와 M-201 품종에서 각각 0.2m/일와 0.4m/일로 측정하였다. 이상의 결과, 도열병에 대한 품종저항성의 차이는 감염속도뿐만 아니라 확산경사의 측정에 의하여 효과적으로 감지될 수 있다고 생각된다.

• 한국수산과학회지
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• 제42권1호
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• pp.68-72
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• 2009

To gain a greater understanding of the potential for future harmful algal bloom (HAB) outbreaks and to trace the dispersal paths of dinoflagellates, sediment samples were collected from 13 stations in the southeastern Yellow Sea. 23 different types of dinoflagellate resting cysts were identified from the samples. Protoceratium reticulatum (1-391 cells/g dry weight), Gonyaulax scrippsae (0-254 cells/g dry weight), G. spinifera (0-301 cells/g dry weight) and Alexandrium spp. (ellipsoidal type) (0-76 cells/g dry weight) were the dominant species at all surveyed stations. The overall distribution pattern demonstrated that the resting cyst densities were highest in the offshore area and decreased gradually toward the Korean coast. On the other hand, the composition rate of resting cysts of the heterotrophic dinoflagellate species to the total dinoflagellates was higher in the Korean coast region than in the offshore area. We supposed that this distribution pattern of dinoflagellate resting cysts appeared to be influenced by the hydrographic features and environmental conditions of the Yellow Sea.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권1호
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• pp.155-164
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• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• Mycobiology
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• 제38권4호
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• pp.286-294
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• 2010

Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.

• Mycobiology
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• 제38권4호
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• pp.229-237
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• 2010

Members of the genus Aspergillus are the most common fungi and all reproduce asexually by forming long chains of conidiospores (or conidia). The impact of various Aspergillus species on humans ranges from beneficial to harmful. For example, several species including Aspergillus oryzae and Aspergillus niger are used in industry for enzyme production and food processing. In contrast, Aspergillus flavus produce the most potent naturally present carcinogen aflatoxins, which contaminate various plant- and animal-based foods. Importantly, the opportunistic human pathogen Aspergillus fumigatus has become the most prevalent airborne fungal pathogen in developed countries, causing invasive aspergillosis in immunocompromised patients with a high mortality rate. A. fumigatus produces a massive number of small hydrophobic conidia as the primarymeans of dispersal, survival, genome-protection, and infecting hosts. Large-scale genome-wide expression studies can now be conducted due to completion of A. fumigatus genome sequencing. However, genomics becomes more powerful and informative when combined with genetics. We have been investigating the mechanisms underlying the regulation of asexual development (conidiation) and gliotoxin biosynthesis in A. fumigatus, primarily focusing on a characterization of key developmental regulators identified in the model fungus Aspergillus nidulans. In this review, I will summarize our current understanding of how conidiation in two aspergilli is regulated.

• The Korean Journal of Ecology
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• 제20권4호
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• pp.265-274
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• 1997

All landscapes are mosaics of habitat patches of different types. Therefore, there are always edged between habitat patches in a landscape. Forest animal has an important role in vegetation development and maintenance by seed dispersal around forest. Movement of animals depends on the spatially heterogeneous structure and pattern of vegetation landscapes because each animal has special habitats in a landscape. Especially, forast edge with high permeability and prey density is one of the important habitats to the animals. Therefore, understanding the ecological characteristics of the forest edges as a corridor connecting mosaic vegetation patches is necessa교 새 establish the strategies for the nature conservation and sustainable vegetation management. Under this idea, we examined the animal influenced on pine seeds as one of the method of monitoring the animal activity in mosaic vegetation. Man-made mosaic vegetations including open, edge and inner forests were carefully selected in the rural landscape. We carried out predation test on pine seeds during one year. A result was that damages on seed was more significant at forest edge than inner and open forest. Pine seed on seedbeds was mainly attacked by squirrels and mice than birds. Pine seed was damaged by squirrels in different types of vegetation by seasons. Rate of seed predation at forest edge was, in special, higher than that of other sites. According to this results, it is suggested that the relationship between animal behavior and spatial vegetation structure relating to human impact such as the distance from settlement to vegetation appeares to be in the rural vegetation landscape.

• ALGAE
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• 제31권4호
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• pp.303-315
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• 2016

Compsopogon specimens collected in China were examined based on morphology and DNA sequences. Five molecular markers from different genome compartments including rbcL, COI, 18S rDNA, psbA, and UPA were identified and used to construct a phylogenetic relationship. Phylogenetic analyses indicated that two different morphological types from China clustered into an independent clade with Compsopogon specimens when compared to other global samples. The Compsopogon clade exhibited robust support values, revealing the affiliation of the samples to Compsopogon caeruleus. Although the samples were distributed in a close geographical area, unexpected sequence divergences between the Chinese samples implied that they were introduced by different dispersal events and from varied origins. It was speculated that Compsopogon originated in North America, a portion of the Laurentia landmass situated in the Rodinia supercontinent at approximately 573.89-1,701.50 million years ago during the Proterozoic era.Although Compsopogonhad evolved for a rather long time, genetic conservation had limited its variability and rate of evolution, resulting in the current monospecific global distribution. Additional global specimens and sequence information were required to increase our understanding of the evolutionary history of this ancient red algal lineage.

• Parasites, Hosts and Diseases
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• 제40권3호
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• pp.139-148
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• 2002

In order to study the range of flight and feeding activity of Anopheles sinensis, the dispersal experiment was conducted in Paju city, located in the northern part of Gyeonggi-do, Republic of Korea, during the period of 7th to 28th September 1998. Unfed females An. sinensis were collected in cowshed and released after being marked with fluorescent dye at 23:00 hours on the same day. Released female mosquitoes were recaptured everyday during 21 days using light traps, which were set at 10 sites in the cowsheds located 1, 3, 6, 9 and 12 km north-northwest and north-northeast and at 3 sites located 1, 6 and 9 km toward south-west from the release point. In addition, to study the longest flight distance in one night, we set the light traps at 16 and 20 km toward north-northeast from the release site. All the collected mosquitoes were placed on filter papers and observed on UV transilluminator after treatment with one drop of 100% ethanol. Out of 12,773 females of An. sinensis released, 194 marked females mosquitoes were recaptured, giving 1.52% recapture rate. Of 194, 72 mosquitoes (37 1%) were recaptured in light traps from three places set at 1 km from the release point, 57 mosquitoes (29.4%) from two places at 1-3 km, 41 mosquitoes (21.1%) from three places at 3-6 km, 20 mosquitoes (10.3%) from three places at 6-9 km, and 4 mosquitoes (2.1%) from two places at 9-12 km. Since 170 female mosquitoes (87.6%) out of 194 marked mosquitoes were captured within 6 km from the release point, this flight radius represents the main activity area. An. sinensis was found to be able to fly at least 12 km during one night.

• 한국환경생태학회지
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• 제30권4호
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• pp.658-675
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• 2016

분포지의 환경특성, 개체군구조, 생태적지위, 생활사 특성 그리고 개체군 통계적 연구는 효과적인 보전을 위해 필수적인 정보이다. 우리는 12년간의 분포조사를 통해 총 37개의 분포지를 확인하였고 그중 12개 지역에 있는 25개의 집단을 대상으로 생육지의 환경과 개체군 구조를 조사하였다. 강원도 평창군 대관령면의 8개 집단을 대상으로 4년간에 걸친 개체군동태를 조사하였다. 4년간의 재배실험과 화분매개곤충의 영향을 관찰하였다. 조사결과 산작약은 비교적 넓은 식생환경에 걸쳐 분포하였다. 조사가 이루어진 25개 집단의 개체군 구조는 비교적 안정적인 집단과 극단적으로 성체만이 존재하는 집단 등 상당한 차이를 나타내었다. 조사기간 동안 상층식생에 생성된 숲 틈이 개체군 동태에 영향을 미치는 요인으로는 추정되었다. 재배실험에서 유묘는 토양의 유기물이 상대적으로 적은 곳에서 잘 성장하였다. 화분매개곤충의 방문이 결실한 종자의 수와 결실률에서 높게 나타나는 경향이 있었다. 결론적으로, 산작약의 분포는 환경적 요인과 더불어 분포에 관여하는 다른 요인의 연구가 필요하며 그 중에서 종자의 운반체에 대한 연구의 필요성을 제안하였다. 현재의 산작약 개체군은 과거 급격한 분포지의 감소 이후 확대되는 과정으로 평가되었다. 멸종위기야생식물인 산작약의 효과적인 보전을 위해서는 시공간적 확장을 통한 종에 대한 이해와 이를 바탕으로 한 생태계의 건강성 유지를 제안하였다.

• 환경생물
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• 제40권1호
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• pp.25-53
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• 2022

본 연구에서는 오늘날 바닷새 및 해양어류의 이동 연구방법 및 내용의 동향을 고찰하고, 기존 동물 이동 연구의 기본 틀에 의거하여 향구 연구방향에 관하여 제언하였다. 연구방법론적 측면에서는 과학기술의 발달에 따라 전파추적 기법, 음향추적 기법, RFID, 위성추적 기법, 지오로케이터 등을 이용한 위치추적 기법이 바닷새 및 해양어류의 이동 연구에 널리 활용되고 있으며, 개체군의 분포 및 밀도조사, 안정성 동위원소 등 체내 물질 분석을 통한 연구도 이루어진다. 연구내용의 경우, 크게 환경요인이나 종간 경쟁 등의 외적 요인, 호르몬을 비롯한 체내 물질과 같은 내적 요인, 어업활동이나 해상풍력단지 건설 등의 인위적인 활동, 그리고 기후변화가 바닷새와 해양어류의 이동에 미치는 영향 등이 다루어지고 있다. 추후 연구에서는 내적 요인과 관련하여 이동과 분산에 영향을 주거나 유발하는 요인이 되는 체내 생리적 요인이나 변화를 규명하고, 이동 능력 분석을 위하여 자기장의 변화가 조류 및 어류의 이주 능력에 미치는 영향이나 종별 시공간적 이주 능력의 차이, 이주 정확성 및 성공률에 영향을 미치는 요인에 관한 연구가 필요할 것으로 제언한다. 또한 외부 환경적 요인과 관련해서는 어업활동이나 해상풍력 등의 방해요인과 기후변화가 해양동물들의 이주 및 분산 패턴에 미치는 영향에 대한 연구의 필요성이 대두되며, 마지막으로 여러 생태적 측면에서 서로에게 직·간접적인 영향을 미치는 바닷새와 해양어류에 대한 융합적인 연구가 요구된다.