본 논문에서는 비평형 분자동역학 시뮬레이션 기법을 사용하여 알루미늄 박막과 실리콘 웨이퍼 간 열경계저항을 예측하였다. 실리콘의 끝 단 고온부에 열을 공급하고, 같은 양의 열을 알루미늄 끝 단 저온부에서 제거하여 경계면을 통한 열전달이 일어나도록 하였으며, 실리콘 내부와 알루미늄 내부의 선형 온도 변화를 계산함으로써 경계면에서의 온도 차이에 따른 열저항 값을 구하였다. 300K 온도에서 5.13±0.17m2·K/GW의 결과를 얻었으며, 이는 열유속 조건의 변화와 무관함을 확인하였다. 아울러, 펨토초 레이저 기반의 시간영역 열반사율 기법을 사용하여 열경계저항 값을 실험적으로 구하였으며, 시뮬레이션 결과와 비교·검증하였다. 전자빔 증착기를 사용하여 90nm 두께의 알루미늄 박막을 실리콘(100) 웨이퍼 표면에 증착하였으며, 유한차분법을 이용한 수치해석을 통해 열전도 방정식의 해를 구해 실험결과와 곡선맞춤 함으로써 열경계저항을 정량적으로 평가하고 나노스케일에서의 열전달 현상에 관한 특징을 살펴보았다.

Ticks and mosquitoes are well known as the most dangerous animals in the world. During the blood feeding, they can transmit a variety of pathogens (bacteria, virus, and protozoa) causing human diseases such as SFTS (severe fever with thrombocytopenia syndrome), malaria, Zika, and dengue. In Korea, SFTS is a newly emerging vector-borne disease transmitted by Asian longhorned tick, Haemaphysalis longicornis. However, there are no effective methods to control ticks and tick-borne disease. The laboratory of medical entomology at Kyungpook national university is focusing on not only fundamental biology of hard ticks in Korea including life cycle and host ranges but molecular physiology and comparative transcriptomics to understand interactions between vector and pathogen at the molecular level. We are also focusing on molecular physiological mechanisms of mosquito salivary secretion by investigating the function of neuropeptides and G protein-coupled receptors (GPCRs) in the salivary glands of Asian tiger mosquito, Aedes albopictus. We believe that understanding the biology of blood feeding arthropods will lead us to the development of novel methods for the disruption of feeding, thus allowing for the prevention of pathogen transmission.

Insect cuticle or exoskeleton is a complex extracellular matrix formed primarily from structural polysaccharide chitin and protein, and it plays a critical role in protecting them from various environmental stresses and pathogenic infection. Despite of limited composition, insect cuticle has remarkably diverse mechanical properties, ranging from soft and flexible to hard and rigid. My research has been focusing on functional importance of the genes involved in chitin metabolism and cuticle tanning (sclerotization and pigmentation) to comprehensively understand the genetic, enzymatic as well as molecular mechanism underlying differentiation, development and formation of insect cuticular extracellular matrices.

In the lab of insect molecular physiology, Kyungpook national university, we are studying insect physiology with molecular biological tools. First research interest is the comparison study on the physiological differences between two taxonomically close flies, Drosophila melanogaster and Drosophila suzukii being adapted to fermented and fresh fruits, respectively. We are also studying the non-neuronal function of soluble acetylcholinesterase and its specific roles in insect sociality. For the climate change vector surveillance center project, we are monitoring the population of ticks and mosquitoes in Gyeongbuk region and detecting the pathogens in the host arthropods. In addition, we are investigating the genes encoding acetylcholinesterase and voltage-sensitive sodium channel in Hemaphysalis longicornis and the point mutations putatively involved in pesticide resistance.

The disadvantage of the current Red imported fire ants (RIFA) diagnostic is that it takes at least two days, because it is subjected to PCR amplification and DNA sequence identification process using an arthropod universal mitochondrial cytochrome oxidase I prime pair after genomic DNA extraction. In order to overcome this drawback, two RIFA specific genes were confirmed and used to develop techniques for identifying the species using various PCR methods. The conventional PCR method can be confirmed by the presence of amplified DNA, but additional time is required to confirm whether the PCR products are present or not. In contrast, SYBR green Real Time (RT) PCR or TaqMan probe RT PCR method has the advantage of confirming the results immediately after the reaction is completed. The new molecular diagnostic method has the advantage of shortening the time of two days, which is the biggest disadvantage of RIFA molecular diagnostic method, to 3 hours or less.

Drosophila suzukii (Matsumura), commonly called the Spotted Wing Drosophila (SWD), originally from South Asia, is a major pest in orchards. Recently, chemical control was applied to prevent the SWD in cultivated fields, but it was not much effective because D. suzukii tended to avoid place where insecticide was treated, to reproduce in wild field, and then to recolonize neighboring cultivated fields. In contrast to chemical control, biological control can reduce these problems by using natural enemies who attack the D. suzukii. Some species of genus Asobara (Hymenoptera; Braconidae; Alysiinae) are parasitoids of Drosophila, and, In South Korea, there are 3 species recorded parasitizing in D. suzukii. In this study, we used morphological characters and mitochondrial COI gene to identify Asobara species. As a result, one species was found as a possible parasitoid of D. suzukii.

In the 21st century, the risk of the exotic pest being invaded is increasing due to the rise of trading activities. Oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae), has been considered to very destructive invader as it is highly intrusive and has a wide host range. In this study, 2,299 samples were collected from 88 locations in 12 countries by quarantine and investigation. Among them, 608 individuals (including B. correcta) were used for COI DNA barcoding analysis based on Neighbor Joining method with P-distance model. Population genetics analysis was conducted for 510 individuals selected from 47 locations of 12 Southeast Asian countries using 15 microsatellite loci. The barcoding analysis resulted in that any clade was not clustered according to a geographical isolation but indicated geographically mixed populations. Population genetics analysis showed shared genetic structure between neighboring countries across borders. Genetic structure of most Korean quarantine groups was more similar to that of Taiwan, China and Thailand in the order of appearance than other countries.

The fall armyworm (FAW), Spodoptera frugiperda J.E. Smith is a noctuid moth endemic throughout the Western Hemisphere that has recently become widespread in sub-Saharan Africa. In Asia, FAW was firstly reported at corn fields in India, SriLanka, Bangladeshi, Miyanmar and Thailand in 2018. In January 2019, FAW was also found in Yunnan province of China. In March 2019, the larvae which could be tentatively identified as FAW were caught at a corn field of Plant Protection Center of Lao PDR, which is located in Vientiane, Laos. Species identification was confirmed by DNA barcoding using the COⅠ segment of the four larvae, which were found to be the haplotype of rice strain (COⅠ-RS). The host strain identity was additionally analysed as a Tpi-C (C-strain allele) by Triosephosphate isomerase gene (Tpi) segment located on the Z sex chromosome. The result shows that the FAW specimens in Lao is the subpopulation of COⅠ-RS/Tpi-C (COⅠ and Tpi haplotype combination). It was reported that COⅠ-CS/Tpi-C were more frequently observed than COⅠ-RS/Tpi-C in Western Hemisphere and Western Africa, but COⅠ-RS/Tpi-C were more frequently observed in Eastern Africa. It can be supposed that the subpopulation of COⅠ-RS/Tpi-C in Lao is one of the subpopulations which have migrated into the Indochinese peninsula from Eastern Africa, with more detailed analysis for more diverse nationwide specimens left.

Coccidae is one of the major families of scale insects, with many species considered to be serious agricultural or horticultural pests. However, the phylogenetic relationships among coccid subfamilies, tribes and genera are poorly understood because the previous hypotheses are based only on morphological characters and cladistic analysis. Here, we present the first molecular phylogeny of the family based on DNA fragments of a mitochondrial gene (COI), nuclear ribosomal RNA genes (18S and 28S), and elongation factor-1α (EF-1α). We recover a monophyletic family Coccidae with strong support. However, some genera (Coccus and Pulvinaria), tribes (Coccini, Paralecaniini, Pulvinariini and Saissetiini) and subfamilies (Coccinae and Filippiinae) within the family found to be paraphyletic- or polyphyletic. Moreover, particular types of wax formation, which have been used as important taxonomic characters in Coccidae, were found in several unrelated taxa.

The genus Rosalia contains three subgenera of which distinctly divided by different body colors and distributional patterns. Eurybatodes is a monotypic subgenus with yellow tegument only found in Yunnan, China. Eurybatus is the most specious subgenus contains 21 species with reddish body color, widely distributed in Oriental region including Taiwan and Ryukyu islands. The blue subgenus Rosalia contains 5 species that distributes West Palaearctic, East Palaeartic, Japan, Oriental and West Nearctic, respectively. Here we present the ongoing research on multi-gene phylogeny and evolutionary studies of the genus Rosalia. This study provides new insight into the internal relationships and the evolutionary history of various traits (e.g. biogeography, colors, elytral patterns) of the genus Rosalia.

One of major mechanisms of insecticide resistance is the reduced susceptibility caused by mutations on the main target sites, such as sodium channel and acetylcholinesterase. Bioassay is a useful method to diagnose insecticide resistance of mosquitoes; however, it is hard to establish regional/annual resistance database based on bioassay. Recently, various markers of mutation and copy number variation have been identified through insecticide mechanism studies. Thus, molecular detection of resistance based on the resistance marker is now feasible, which can be readily implemented as a novel resistance monitoring tool to complement or replace the conventional bioassay method. In Korea, the density of vector mosquitoes native to the subtropical areas has increased due to climate change. Therefore, it is required to establish an efficient resistance monitoring system based on molecular markers to facilitate the construction of a nation-wide resistance map for more effective control of mosquitos. In addition, alternative insecticides should be introduced to the areas where mosquitoes develop high levels of resistance to maximize control efficacy against resistant populations

미세방울 디지털 PCR(Droplet digital PCR, ddPCR) 법은 정량 PCR 법과 같이 형광물질을 사용하여 정량분석이 가능하다는 점은 유사하지만, PCR 반응액을 만든 후 이 반응액을 바로 PCR에 사용하지 않고 수 만 개의 동일한 크기의 미세방울(droplet)로 구획(partitioning)한 후에 PCR 반응을 수행하는 점이 기존의 PCR 법과 가장 큰 차이라고 볼 수 있다. 이렇게 구획된 나노리터 크기의 미세방울 중에서 형광신호가 검출되는 미세방울과 검출되지 않은 미세방울의 수를 계수하여 프아송 분포(Poisson distribution) 계산에 적용하면 표준검량선 없이 목적 유전자의 절대정량 분석이 가능하다. 곤충이 매개하는 질병 바이러스의 경우 소량의 바이러스 감염 여부를 확인하기 위해서 다수의 곤충 유전자를 확인해야 하는데, 이와 같이 미세방울 형태의 ddPCR을 이용하면 기존 Real-time PCR 법에 비해 극소량의 목적 유전자를 높은 민감도로 검출할 수 있으며, PCR 저해요소(inhibitor)에도 큰 영향을 받지 않는다는 장점이 있다. 또한 미세방울 방식의 디지털 PCR을 이용하면 다중 PCR 분석이 가능하여 1개의 시료에서 다양한 질병매개 바이러스를 검출할 수 있다.

최근 우리나라 연안에서 출현빈도가 점차 늘어나고 있는 침편모조류에 속하는 Chattonella는 대표적인 유해조류 중 하나로, 이들 종은 세포벽이 없어, 단순히 세포의 형태나 크기 등 광학현미경 관찰만으로는 정확하게 동정하는 것이 어렵다. 따라서 본 연구에서는 2017년 득량만에서 발생한 Chattonella 적조 시료를 대상으로 단일 세포를 분리하고, 이들 시료의 28s rDNA, rbcL, psaA 영역을 대상으로 single-cell PCR 기법을 이용하여 종 동정을 실시하였다. 현미경 관찰 결과 장축은 평균 74.0±10.1㎛이고 단축은 평균 33.1±3.6㎛로 일반적인 Chattonella의 형태적 특징을 보였다. 28s rDNA, rbcL, psaA 영역을 대상으로 한 염기서열 비교 결과에서는 세 영역 모두에서 하나의 종으로 명확히 구분되지는 않았다. 하지만 C. marina, C. marina var. antiqua, C. marina var. ovata 그룹과 99~100% 높은 서열 유사성을 보였다.

우리는 오리온 분자운 복합체의 북부 필라멘트(이하 NF)에 대하여 12CO (J=1-0) 분자선의 자료를 이용하여 은하 평면이 분자의 운동과 운동학에 미치는 영향을 연구하였다. 6 m 서울대학교 전파망원경(Seoul Radio Astronomy Observatory, SRAO)을 이용하여 2arcmin 공간분해능으로 은하면으로부터 먼 순서로 NF1, NF2, NF3 세 곳을 총 270시간 동안 관측된 자료를 사용하였다. 은하면과 OMC NF는 12CO (J=2-1) 경우 3% 밀도에서, 티끌의 경우 9% 밝기 수준에서 자기장을 따라 서로 연결되어 있었다. 12CO (J=1-0), 12CO (J=2-1), 성간 티끌 관측결과를 비교해본 결과, 세 경우 모두 NF3에서는 고루 분포했지만, NF1과 NF2에서는 비교적 밀도가 높은 특정 영역에서만 함께 나타났다. NF는 단일 구조를 보였으며, NF1에서는 부분 수축 운동을, NF2에서는 하단에서 회전 운동이 나타났고, NF3에서는 유일하게 명확히 자기장에 연관된 나선형 회전이 보였다. 위치-속도 분석 결과, 12CO (J=1-0)를 비롯한 물질들은 NF2와 NF3을 따라 은하면을 향하여 흐를 가능성이 있음을 확인할 수 있었다. 은하면을 향하여 물질이 흐르는 명백한 원인을 이번 연구결과에서 볼 수 없었지만 추후의 더 정교한 관측결과가 NF1과 NF2 상단부의 회전 운동을 확인 할 수 있겠다.

탄소나노튜브(CNT) 기반의 멤브레인은 높은 물 전달률과 직경에 따른 이온 배제율로 해수담수, 물질 정화 등을 위한 분리막으로써의 가능성을 보여 주었다. 이온 선택성은 CNT 기반 멤브레인의 응용 분야를 확대하기 위한 중요한 요소이며, 기능기를 이용하여 이온 선택성의 조절이 가능함이 보고되었다. 다양한 원자가/크기의 이온이 혼합될 경우, 이온-기능기간 작용력 뿐만 아니라 이온-이온간의 작용력, 이온의 크기에 의한 반발력 등이 복합적으로 작용한다. 이에 본 연구에서는 분자동역학 전산모사를 통하여, 상이한 원자가/크기를 가진 이온의 혼합이 기능화된 CNT의 이온 선택성에 미치는 영향을 연구 하였다. Potential of Mean Force 계산을 통하여 이온 투과에 대한 자유 에너지 장벽을 계산하였으며, CNT 크기 변화, 전하량 변화를 통하여 이온 선택성과 배제에 영향을 미치는 요소를 분석하였다. 본 연구는 CNT 멤브레인을 이용한 분리막 설계, 생체 이온 전달 채널 모사 등에 유용할 것으로 기대한다.