• Entomological Research
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• 제48권5호
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• pp.362-371
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• 2018

Chemical insecticides released into the environment may have adverse biological effects. Therefore, there is a need for ecofriendly insecticides for mosquito control. Xerophytic plant extracts that may provide more ecofriendly active component were evaluated against Culex pipiens 4th instars. Plant extracts prepared using different solvents with a Soxhlet apparatus and different concentrations were tested against Culex pipiens larvae. The effects were observed at 24 h and 72 h intervals and $LD_{50}$ and $LD_{90}$ values determined. Chloroform ($CHCl_3$) and ethyl acetate (EtOAc) extracts of Althaea ludwigii were the most effective against Cx. pipiens $4^{th}$ instars, but were highly dependent on extract concentrations and exposure time. Results suggest that A. ludwigii extracts contain bioactive compounds, such as phenols and saponins, that may provide effective Cx. pipienslarval control. However, the extract was found to be toxic to zebrafish larvae, and may be toxic to other aquatic fauna. Further studies to determine the active components and toxicity to other fauna are needed.

• 대한수의학회지
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• 제61권2호
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• pp.12.1-12.9
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• 2021

The mosquito-borne pathogen Zika virus may result in neurological disorders such as Guillain-Barré syndrome and microcephaly. The virus is classified as a member of the Flaviviridae family and its wide spread in multiple continents is a significant threat to public health. So, there is a need to develop animal models to examine the pathogenesis of the disease and to develop vaccines. To examine the clinical profile during Zika virus infection, we infected neonatal and adult wild-type mice (C57BL/6 and Balb/c) and compared the clinical signs of African-lineage strain (MR766) and Asian-lineage strain (PRVABC59, MEX2-81) of Zika virus. Consistent with previous reports, eight-week-old female Balb/c mice infected with these viral strains showed no changes in body weight, survival rate, and neurologic signs, but demonstrated increases in the weights of spleens and hearts. However, one-day-old neonates showed significantly lower survival rate and body weight with the African-lineage strain than the Asian-lineage strain. These results confirmed the pathogenic differences between Zika virus strains. We also evaluated the clinical responses in neonatal and adult mice of different strains. Our findings suggest that these are useful mouse models for characterization of Zika virus for vaccine development.

• Parasites, Hosts and Diseases
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• 제59권2호
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• pp.173-178
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• 2021

The DM9 domain is a protein unit of 60-75 amino acids that has been first detected in the fruit fly Drosophila as a repeated motif of unknown function. Recent research on proteins carrying DM9 domains in the mosquito Anopheles gambiae and the oyster Crassostrea gigas indicated an association with the uptake of microbial organisms. Likewise, in the trematode Fasciola gigantica DM9-1 showed intracellular relocalization following microbial, heat and drug stress. In the present research, we show that FgDM9-1 is a lectin with a novel mannose-binding site that has been recently described for the protein CGL1 of Crassostrea gigas. This property allowed FgDM9-1 to agglutinate gram-positive and -negative bacteria with appropriate cell surface glycosylation patterns. Furthermore, FgDM9-1 caused hemagglutination across all ABO blood group phenotypes. It is speculated that the parenchymal located FgDM9-1 has a role in cellular processes that involve the transport of mannose-carrying molecules in the parenchymal cells of the parasite.

• 한국습지학회지
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• 제20권2호
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• pp.155-160
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• 2018

본 연구는 기후변화로 모기 매개 질병이 확산되고 있는 범지구적 차원에서 주요 질병을 매개하는 흰줄숲모기(Aedes albopictus) 유충의 생장이 여러 가지 온도 조건에 따라 어떻게 변화하는지를 확인하기 위하여 수행되었다. 흰줄숲모기 유충 120개체를 채집하여 120개의 $20m{\ell}$ 유리용기(vial)에 한 개체씩 넣어 12개의 수조($17{\times}24{\times}18cm^3$)에 유리용기를 10개씩 분리하고, 3반복수의 수조를 4가지 온도($17^{\circ}C$, $21^{\circ}C$, $24^{\circ}C$, $28^{\circ}C$)로 조절된 배양기에 배치시켰다. 각 수조는 1령 3개체, 2령 3개체, 3령 2개체, 4령 2개체로 구성하여 흰줄숲모기 유충의 온도에 따른 우화율 및 생장 단계 별 평균 사망률, 온도에 따른 생장 단계별 최저 사망률, 온도에 따른 평균 수중 생존기간에 대한 연구를 27일 동안 진행하였다. 그 결과, 온도에 따른 평균 우화율은 $21^{\circ}C$에서 $20.00{\pm}5.77%$, $17^{\circ}C$, $24^{\circ}C$, $28^{\circ}C$에서 $3.33{\pm}3.33%$로 나타났다. 생장 단계별 평균 사망률은 1령이 $19.24{\pm}3.65%$, 2령이 $16.48{\pm}3.25%$, 3령이 $23.54{\pm}5.06%$, 4령이 $40.74{\pm}7.08%$로 나타났다. 온도에 따른 생장 단계별 최저 사망률은 1령이 $17^{\circ}C$에서 $13.33{\pm}6.67%$, 2령이 $21^{\circ}C$에서 $7.41{\pm}7.41%$, 3령이 $24^{\circ}C$에서 $10.74{\pm}6.43%$, 4령이 $28^{\circ}C$에서 $20.37{\pm}5.46%$로 나타났다. 온도에 따른 평균 수중 생존기간은 $17^{\circ}C$는 $26.33{\pm}0.67$일, $21^{\circ}C$는 $23.33{\pm}1.33$일, $24^{\circ}C$는 $20.00{\pm}2.52$일, $28^{\circ}C$는 $11.67{\pm}1.20$일로 나타났다. 전체적인 결과를 통해, 흰줄숲모기 유충의 생장은 $21^{\circ}C$가 가장 적절한 온도인 것으로 나타났으며, 생장 단계 중 4령에서 가장 많은 개체가 사망하는 것으로 나타났다. 직접적인 온도 설정을 이용한 흰줄숲모기 유충에 대한 연구 결과는 향후 모기 방제방법의 기초자료로 활용될 것으로 기대된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제3권1호
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• pp.19-23
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• 2001

Two B. thuringiensis strains, which possess mosquitocidal activities, were isolated from Korean soil samples and named K-1205-1 and K-1381-1. Serological studies indicated that K-1205-1 and K-1381-1 belonged to B. thuringiensis subsp. kurstaki (H3a3b3c) and subsp. aizawai (H7), respectively. K-1205-1 produced typical bipyramidal parasporal inclusions, but K-1381-1 produced irregular bipyramidal shape. Total plasmid DNA patterns analysis shewed that K-1205-1 and K- 1381-1 were different from their reference strains, subsp. kurstaki and subsp. aizawai, respectively, in high molecules, whereas their crystal protein patterns showed no difference. The cry gene contents of K-1205-1 and K-1381-1 were identical with those of the reference strains. Mosquitocidal activities of crystal proteins produced by K-1205-1 and K-1381-1 were significantly high by about 40-50 folds at $LC_50$ when compared to those of subsp. kurstaki and subsp. aizawai. Finally, in southern blot analysis using cry1A-type specific probe, K-1205-1 and K-1381-1 had different bands from subsp. kurstaki and subsp. aizawai, respectively. In conclusion, our results suggest that K-1205-1 and K-1381-1 appear to be new moquitocidal B. thuringiensis strains isolated from Korean soil.

• BMB Reports
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• 제37권3호
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• pp.292-297
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• 2004

The current model for the mechanism of action of the Bacillus thuringiensis Cry $\delta$-endotoxins involves the penetration of the ${\alpha}4-{\alpha}5$ hairpin into the target midgut epithelial cell membranes, followed by pore formation. In this study, PCR-based mutagenesis was employed to identify a critical residue within the ${\alpha}4-{\alpha}5$ loop of the 130-kDa Cry4A mosquito-larvicidal protein. Alanine-substitutions of two charged (Asp-198 and Asp-200) and four polar (Asn-190, Asn-195, Tyr-201 and Tyr-202) residues in the ${\alpha}4-{\alpha}5$ loop were performed. Like the wild-type, all of the mutant toxins were over-expressed as inclusion bodies in Escherichia coli. When E. coli cells expressing each mutant toxin were bioassayed against Aedes aegypti larvae, larvicidal activity was completely abolished for the substitution of only Tyr-202, while replacements at the other positions still retained a high level of toxicity. Further replacement of Tyr-202 with an aromatic side chain, phenylalanine, did not affect the toxicity. These results revealed a crucial role in toxin activity for the conserved aromatic residue at the 202 position within the ${\alpha}4-{\alpha}5$ loop of the Cry4A toxin.

• Parasites, Hosts and Diseases
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• 제39권2호
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• pp.185-192
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• 2001

To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from .lune to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Anopheles sinensis from human baiting collections fluctuated from 41% to 71% (average 48.8%) of which the rate gradually increased as time passed on: 35.2% in Jun. ; 55.0% in July; 66.2% in Aug. From this proportion of parous, we could estimate the probability of daily survival rate of An. sinensis to be 0.79 assumed with 3 days gonotrophic cycle and the expectancy of infective life through 11 days could be defined as 0.073. Blood meal analysis was performed using ELISA to determine the blood meal source. Only 0.8% of blood meals were from human hosts. We could conclude that An. sinensis is highly zoophilic (cow 61.8%) Malaria is highly unstable (stability index < 0.5) in this area. From these data, vectorial capacity VC) was determined to be 0.081. In spite of a high human biting rate (ma), malaria transmission potential is very low due to a low human blood index. Therefore, we could conclude that malaria transmission by An. sinensis is resulted by high population density, not by high transmission potential. For this reason, we need more effort to decrease vector population and vector-human contact to eradicate malaria in Korea.

• Parasites, Hosts and Diseases
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• 제44권4호
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• pp.285-294
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• 2006

Changing patterns of the reemerging Plasmodium vivax malaria in the Republic of Korea (South Korea) during the period 1993 to 2005 are briefly analyzed with emphasis on the control measures used and the effects of meteorological and entomological factors. Data were obtained from the Communicable Diseases Monthly Reports published by the Korea Center for Disease Control and Prevention, and webpages of World Health Organization and United Nations. Meteorological data of Kangwon-do (Province) were obtained from local weather stations. After its first reemergence in 1993, the prevalence of malaria increased exponentially, peaking in 2000, and then decreased. In total, 21,419 cases were reported between 1993 and 2005 in South Korea. In North Korea, a total of 916,225 cases were reported between 1999 and 2004. The occurrence of malaria in high risk areas of South Korea was significantly (P < 0.05) correlated with the mosquito population but not with temperature and rainfall, Control programs, including early case detection and treatment, mass chemoprophylaxis of soldiers, and international financial aids to North Korea for malaria control have been instituted. The situation of the reemerging vivax malaria in the Republic of Korea is remarkably improving during the recent years, at least in part, due to the control activities undertaken in South and North Korea.

• 한국발생생물학회지:발생과생식
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• 제8권1호
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• pp.19-25
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• 2004

Pax6는 진화적으로 잘 보존된 homeobox유전자 그룹의 하나로 배 발생기 동안 시공간적으로 제한되어 발현된다. 이 실험은 말라리아 매개모기인 Anopheles stephemi에서의 Pax6 발현을 서로 다른 분자환경 조건에서 조사해 보기 위해 트랜스포존의 하나인 piggyBac과 Pax6에 결합하는 3xp3-EGFP를 사용한 생식세포 형질전환 방법을 사용하였다. 4개의 형질 전환 계열이 만들어졌고 형질전환율은 6.7%였으며, 도입 유전자는 여러 세대에 걸쳐 안정적으로 발현되었다. 4계열은 3가지의 공간적 발현 형태를 보였으며 이는 트랜스포존 삽입 위치에 따른 enhancing혹은 silencing의 결과로 예상된다. 이 결과를 통해 트랜스포존 piggyBac을 사용한 형질전환 시스템은 일반적인 보고자 유전자 발현 실험에서 다양한 형태의 공간적 발현 결과를 유도하는 매우 효율적인 방법으로 사용될 수 있으리라 예상된다

• Animal Systematics, Evolution and Diversity
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• 제11권1호
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• pp.87-100
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• 1995

1994년 7월 전라남도 진도에서 위생절지동물상을 조사하였다. 모기는 8종이 채집되었는데 그중 일본뇌염 매개종인 작은빨간집모기(Culex tritaeniorhynchus)가 우점종이었다. 신종으로 보이는 Cluex sp. 유충이 채집되었는데 명명은 성충이 채집되지 않아 보류하였다. 깔따구는 모두 11속 23종이 채집되었는데 그 중 Cladopelma viridula(녹색사촌무깔따구, 신칭), Dicrotendipes septem-maculatus(여섯점갈래깔따구, 신칭) 및 Harnischia urtilamellata(혹무깔따구, 신칭)는 한국 미기록종이어서 자세히 재기재하였다. 깔따구류중 우점종은 안개무늬날개깔따구(Chironomus kiiensis)이었고(67.3%), 노란털깔따구(Ch. flaviplumus)가 그 다음이었다(15.6%), 등에모기는 모두 5종이 채집되었고 그 중 Culicoides punctatus가 88.7%로 우점종이었다. Foreipomia sp.도 채집되었는데 이 속은 한국에서 처음으로 기록되는 것이다. 들쥐 채집결과는 등줄쥐(Apodemus agrarius)가 높은 밀도를 보였고 등줄쥐에 기생하는 외부기생 절지동물로 Leptotrombidium orientale, Ixodes nipponensis, Laelaps jettmani, Eulaelaps stabularis 등이 동정되었다.