• The Plant Pathology Journal
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• 제30권1호
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• pp.43-50
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• 2014

Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.

• 한국수산과학회지
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• 제48권1호
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• pp.104-115
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• 2015

This study was conducted during April-June in 2008 and 2010, following the Taean Oil Spill. We measured year-to-year changes in benthos species abundances and composition in 16 intertidal zone regions of Chungcheongnam-do. In total, 154 species were found 2008 and 134 in 2010; the mean abundance per area was $403ind./m^2$ and $242ind./m^2$, respectively. In 2008, the 10 dominant species included four species of arthropods, three species of annelids, and three species of mollusks. In 2010, dominant species included five species of annelids, three species of mollusks, one species of arthropods, and one other species. We used bray-curtis similarity to group species and found two groups in 2008 and five in 2010, complementing our NMDS analysis. Finally, we tested correlations between abiotic and biotic factors, and implemented a BIO-ENV analysis, which showed that sediment type, MZ (Phi), and organic content are important environmental factors affecting benthos in the Chung-nam tidal flats.

• Journal of Forest and Environmental Science
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• 제29권3호
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• pp.211-218
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• 2013

This study was conducted to examine the community structure of ground beetles between coniferous- and deciduous-dominant forest in agricultural landscapes, in Miryang-si, Yeongdong-gun, Icheon-si, and Cheolwon-gun during April to October in 2009. A total of 19 species belonging to 15 genera of 9 subfamilies were identified from 6,253 collected ground beetles. Dominant species from 4 regions were Synuchus nitidus (3,715 individuals, 59.4% of total) and Synuchus cyloderus (1,783 individuals, 28.5%) respectively. Non-metric multidimensional scaling based on Bray-Curtis similarity showed that ground beetle assemblage was not different between forest stands, but it was significantly different among regions. Overall, forest stands of secondary forests may not show a different community structure of ground beetle assemblages in our study. However, monitoring on the ground beetle fauna as well as other arthropods of secondary forests in agricultural landscapes is still important for the management and conservation of biodiversity, because forests provides important habitats for many predatory arthropods, such as ground beetles, spiders and rove beetles.

• The Korean Journal of Ecology
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• 제21권1호
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• pp.15-26
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• 1998

This study was conducted to analyze arthropod community patterns in smallrice fields managed by different cultural methods [Conventional and Low Input Sustainable Agriculture(LISA)] in Suwon in 1995 and 1996. A half of nitrogen fertilizers and a quarter of pesticides were applied in the LISA field compared to in the conventional field. Total 15 orders and 43 families of arthropods were collected in two years. No differences were found in arthropod abundance and arthropod species composition between two differently practiced fields. The arthropod community was analyzed using guild categories. The arthropods were found in the order of 'pest(phytophag)>natural enemy>non-pest' in their densities. The pest species were mainly Homoptera and dominated by Delphacidae (Nilaparvata lugens Stal and Sogatella furcifera Horvath). They constituted > 80% of pest abundance. The spider was the most dominant group in the natural enemy and constituted > 90% of natural enemy abundance. Hunting spiders constituted > 60% of spider abundance and were dominated by Pirata subpiraticus Bos. et Str.(Lycosidae). Pachygnatha clerki Sundevall(Tetragnathidae), Gnathonarium dentatum Weider and Ummeliata angulituberis Oi(Erigonidae) were the dominant species in webbing spiders.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.371-380
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• 2019

Termites are pests that cause serious economic and cultural damage by digesting wood cellulose. Termites are arthropods and have an epidermis surrounded by a chitin layer. To maintain a healthy epidermis, termites have chitinase (${\beta}$-1,4-poly-N-acetyl glucosamidinase, EC 3.2.1.14), an enzyme that hydrolyzes the ${\beta}$-1,4 bond of chitin. In this study, the amino acid sequence of the gene, which is presumed to be termite chitinolytic enzyme (NCBI accession no. KC477099), was obtained from a transcriptomic analysis of Reticulitermes speratus KMT001 in Bukhan Mountain, Korea. An NCBI protein BLAST search confirmed that the protein is a glycoside hydrolase family 18 (GH18). The highest homology value found was 47%, with a chitinase from Araneus ventricosus. Phylogenetic analysis indicated that the KC477099 protein has the same origins as those of arthropods but has a very low similarity with other arthropod chitinases, resulting in separation at an early stage of evolution. The KC477099 protein contains two conserved motifs, which encode the general enzymatic characteristics of the GH18 group. The amino acid sequences $Asp^{156}-Trp^{157}-Glu^{158}$, which play an important role in the enzymatic activity of the GH18 group, were also present. This study suggests that the termite KC477099 protein is a new type of chitinase, which is evolutionarily distant from other insect chitinases.

• 한국환경과학회지
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• 제30권12호
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• pp.993-1003
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• 2021

It is known that the effect of traditional agricultural techniques of burning farmland such as paddy fields and fields gradually declines and affects both the fauna and flora of the rice paddy as well as pests. Therefore, in this study, a study was conducted to investigate the effects of burning rice paddy fields and rice paddy fields levee on the control effect of winter pests inhabiting agricultural land and the amount of pests generated and damaged during the growing season. As a result of this study, the pest control effect of incineration reduces not only the density of pests, but also beneficial insects (natural enemies) and non-reptiles. It is judged that burning has a very low insect control effect. It is expected to be used as basic data to create a sustainable agricultural environment, such as minimizing various negative effects such as pest control effects, wildfires, and air pollution caused by incineration, and suppressing unnecessary incineration and fine dust generation.

• Applied Microscopy
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• 제50권
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• pp.16.1-16.11
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• 2020

Silk is produced by a variety of insects, but only silk made by terrestrial arthropods has been examined in detail. To fill the gap, this study was designed to understand the silk spinning system of aquatic insect. The larvae of caddis flies, Hydatophylax nigrovittatus produce silk through a pair of labial silk glands and use raw silk to protect themselves in the aquatic environment. The result of this study clearly shows that although silk fibers are made under aquatic conditions, the cellular silk production system is quite similar to that of terrestrial arthropods. Typically, silk production in caddisworm has been achieved by two independent processes in the silk glands. This includes the synthesis of silk fibroin in the posterior region, the production of adhesive glycoproteins in the anterior region, which are ultimately accumulated into functional silk dope and converted to a silk ribbon coated with gluey substances. At the cellular level, each substance of fibroin and glycoprotein is specifically synthesized at different locations, and then transported from the rough ER to the Golgi apparatus as transport vesicles, respectively. Thereafter, the secretory vesicles gradually increase in size by vesicular fusion, forming larger secretory granules containing specific proteins. It was found that these granules eventually migrate to the apical membrane and are exocytosed into the lumen by a mechanism of merocrine secretion.

• Applied Microscopy
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• 제50권
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• pp.20.1-20.9
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• 2020

Arthropods have an open circulatory system with a simple tubular heart, so it has been estimated that the contractile pumping structure of the cardiac muscle will be less efficient than that of vertebrates. Nevertheless, certain arthropods are known to have far superior properties and characteristics than vertebrates, so we investigated the fine structural features of intercalated discs and cardiac junctions of cardiac muscle cells in the black widow spider Latrodectus mactans. Characteristically, the spider cardiac muscle has typical striated features and represents a functional syncytium that supports multiple connections to adjacent cells by intercalated discs. Histologically, the boundary lamina of each sarcolemma connects to the basement membrane to form an elastic sheath, and the extracellular matrix allows the cells to be anchored to other tissues. Since the intercalated disc is also part of sarcolemma, it contains gap junctions for depolarization and desmosomes that keep the fibers together during cardiac muscle contraction. Furthermore, fascia adherens and macula adherens (desmosomes) were also identified as cell junctions in both sarcolemma and intercalated discs. To enable the coordinated heartbeat of the cardiac muscle, the muscle fibers have neuronal innervations by multiple axons from the motor ganglion.

• 한국응용곤충학회지
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• 제56권2호
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• pp.121-133
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• 2017

본 연구에서는 국내 호두나무 재배지에 대한 절지동물의 군집 구조를 파악하고, 주요 해충과 천적의 종류 조사를 위해 수행하였다. 또한 조사방법(털어잡기, 깔때기트랩 및 함정트랩)에 따른 다양성 및 군집구조를 비교하였다. 이를 위해 김천시, 부여군 및 화성시에서 호두나무 재배 농가 1곳씩을 선정하였고, 2016년 5월부터 9월까지 조사하였다. 조사 결과, 총 408종 4,372개체의 절지동물이 채집되었고, 이중 전체 조사지역에서 채집된 종은 63종이었다. 깔때기트랩에서 가장 다양하게 절지동물이 채집되었으며, 함정트랩에서 가장 많은 절지동물이 채집되었다. 또한 깔때기트랩과 털어잡기에 의해 채집된 종 구성은 서로 유사한 특징을 보였다. 본 연구를 통해 지역별로 주요 해충의 발생양상이 다르게 나타났는데, 특히 복숭아명나방, 뽕나무깍지벌레, 호두나무잎벌레, 꽃매미, 미국선녀벌레 및 갈색날개매미충이 잠재적으로 중요한 해충이 될 것이라 생각된다. 이외에도 다수의 포식성 및 기생성 절지동물들이 확인되었고, 이들에 대한 정보들은 향후 호두나무 포장의 관리에 있어 중요한 기초 자료가 될 것이다.

• 한국산림과학회지
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• 제94권6호
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• pp.420-430
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• 2005

피해가 급속히 확산중인 소나무재선충병 방제를 위해 항공방제를 실시하는 소나무림이 증가하면서, 항공방제시 농약침투로 인한 토양생태계 교란의 가능성이 제기되고 있다. 본 연구는 이러한 가능성을 평가하기 위해, 현지 외 야외실험을 BACI 실험설계하에 서울 홍릉시험림의 소나무림에서 면적 $25m^2$인 3개의 방제구와 3개의 대조구를 설치하여 실시하였다. 항공방제 약종인 fenitrothion을 항공방제직후 낙엽에서 검출된 잔류량인 0.0335 kg a.i/ha를 지면에 살포하였다. 농약살포는 2002년 6월 4일, 6월 11일, 6월 29일 3회에 걸쳐 실시하였는데, 살포일은 전년도 부산지역 항공방제일과 동일한 날짜로 선정하였다. 절족동물, 곰팡이, 세균, 방선균 등의 토양생물의 개체수 조사를 살포 전에 2회, 살포기간중에 2회, 마지막 살포후 3회 실시하였다. 살충제의 살포는 토양에 서식하는 절족동물, 곰팡이, 세균, 방선균의 개체수 변화와 이들 토양생물군집의 구조에 유의한 영향을 주지 않아. 항공방제가 소나무림의 토양생물에 큰 영향을 줄 가능성이 낮음을 나타내었다.