• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1915-1918
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• 2008

An entomopathogenic fungus was isolated from an infected aphid. The isolate conformed most closely to Lecanicillium attenuatum CBS 402.78 (AJ292434) based on the internal transcribed spacer (ITS) region of its 18S rDNA, and thus was designated L. attenuatum CNU-23. Laboratory and field evaluations of CNU-23 blastospores were carried out for the control of green peach aphids. The laboratory evaluations of CNU-23 revealed an aphid mortality of about 80% with an estimated $LT_{50}$ of 3.72 days after the application of CNU-23 at $1{\times}10^6$ blastospores/ml. Meanwhile, the field evaluations of CNU-23 performed on greenhouse pepper plants during the rainy season showed an aphid mortality ranging from 72% to 97%. Significant sporulation was observed in the aphids treated with CNU-23. Therefore, the results suggest that L. attenuatum CNU-23 can be used as a biocontrol agent for green peach aphids on greenhouse pepper plants.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1439-1446
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• 2009

Isocarbophos is a widely used organophosphorus insecticide that has caused environmental pollution in many areas. However, degradation of isocarbophos by pure cultures has not been extensively studied, and the degradation pathway has not been determined. In this paper, a highly effective isocarbophos-degrading strain, scl-2, was isolated from isocarbophos-polluted soil. The strain scl-2 was preliminarily identified as Arthrobacter sp. based on its morphological, physiological, and biochemical properties, as well as 16S rDNA analysis. The strain scl-2 could utilize isocarbophos as its sole source of carbon and phosphorus for growth. One hundred mg/l isocarbophos could be degraded to a non detectable level in 18 h by scl-2 in cell culture, and isofenphos-methyl, profenofos, and phosmet could also be degraded. During the degradation of isocarbophos, the metabolites isopropyl salicylate, salicylate, and gentisate were detected and identified based on MS/MS analysis and their retention times in HPLC. Transformation of gentisate to pyruvate and fumarate via maleylpyruvate and fumarylpyruvate was detected by assaying for the activities of gentisate 1,2-dioxygenase (GDO) and maleylpyruvate isomerase. Therefore, we have identified the degradation pathway of isocarbophos in Arthrobacter sp. scl-2 for the first time. This study highlights an important potential use of the strain scl-2 for the cleanup of environmental contamination by isocarbophos and presents a mechanism of isocarbophos metabolism.

• 한국유기농업학회지
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• 제21권3호
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• pp.373-380
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• 2013

2012년 10월 경상남도 진주시 농가포장에 재배중인 성숙기 배 과실에서 분홍빛썩음병이 발생하였다. 병징은 배 과실 표면이 수침상으로 물러지고 썩으면서 그 위에 분홍빛 곰팡이가 많이 형성되었다. 균총의 색깔은 처음에 흰색이고 배양기간이 경과됨에 따라 배지 표면에 분홍빛의 분생포자가 많이 형성되었다. 균사생육 적온은 $25^{\circ}C$이었다. 분생포자의 모양은 서양배형이며 좌우 지그자그로 부착하며 성숙한 분생포자는 2세포로 되어있다. 크기는 $10{\sim}22(34){\times}6{\sim}10(12){\mu}m$이었다. 분생자경은 균사표면에 직립으로 형성하고, 폭이 4~5 ${\mu}m$이고 무색이었다. 동정을 확실시하기 위해 rDNA의 complete internal transcribed spacer(ITS) 영역의 염기서열을 분석하였고, 분석된 염기서열(613 bp)을 BLASTN 프로그램으로 확인한 결과, T. roseum(GenBank accession no. JQ898156)와 99%의 상동성을 나타내었다. 이와 같이 배에서 발생한 병징과 병원균의 균학적 특징을 기초로 하여 이 병을 Trichothecium roseum (Pers.) Link ex Gray에 의한 배 분홍빛썩음병으로 명명하고자 제안한다.

• Parasites, Hosts and Diseases
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• 제58권1호
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• pp.15-25
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• 2020

The third stage larvae (L3) of Anisakis typica were detected in 2 species of threadfin bream, Nemipterus hexodon and N. japonicus, from the Gulf of Thailand, and were morphologically and molecularly characterized. Total 100 threadfin breams, 50 Nemipterus hexodon and 50 N. japonicus, were examined with naked eyes after the opening of abdominal cavity with scissors. Almost all infected larvae remained alive and active even the fish were transported for 1-2 days. Anisakid larvae were exclusively distributed in the body cavity and rarely in the liver. The prevalence of A. typica L3 were 68.0% and 60.0% in N. hexodon and N. japonicus and their infection intensities were 3.5 and 4.2 per fish infected each. Morphological and morphometric analysis were performed by viewing specimens under both a light microscope and a scanning electron microscope. Interestingly, the protruded mucron of Anisakis typica under SEM showed a distinct cylindrical shape that differed from the cone shape of A. simplex. The protruded mucron could be used to identify A. typica L3 larvae in the future. A comparison of the ITS1-5.8S-ITS2 rDNA nucleotide sequences of these species revealed high blast scores with A. typica. Conclusively, it was confirmed that A. typica L3 are prevalent in threadfin breams from the Gulf of Thailand, and their morphological and molecular characters are something different from those of other anisakid larvae, including A. simplex and A. pegreffii.

• Mycobiology
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• 제36권1호
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• pp.13-18
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• 2008

Eight distinct bacteria were isolated form diseased mycelia of the edible mushroom, Pleurotus eryngii. 16S rDNA sequence analysis showed that the isolates belonged to a variety of bacterial genera including Bacillus (LBS5), Enterobacter (LBS1), Sphingomonas (LBS8 and LBS10), Staphylococcus (LBS3, LBS4 and LBS9) and Moraxella (LBS6). Among them, 4 bacterial isolates including LBS1, LBS4, LBS5, and LBS9 evidenced growth inhibitory activity on the mushroom mycelia. The inhibitory activity on the growth of the mushroom fruiting bodies was evaluated by the treatment of the bacterial culture broth or the heat-treated cell-free supernatant of the broth. The treatment of the culture broths or the cell-free supernatants of LBS4 or LBS9 completely inhibited the formation of the fruiting body, thereby suggesting that the inhibitory agent is a heat-stable compound. In the case of LBS5, only the bacterial cell-containing culture broth was capable of inhibiting the formation of the fruiting body, whereas the cell-free supernatant did not, which suggests that an inhibitory agent generated by LBS5 is a protein or a heat-labile chemical compound, potentially a fungal cell wall-degrading enzyme. The culture broth of LBS1 was not inhibitory. However, its cell-free supernatant was capable of inhibiting the formation of fruiting bodies. This indicates that LBS1 may produce an inhibitory heat-stable chemical compound which is readily degraded by its own secreted enzyme.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.262-270
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• 2017

Yersinia enterocolitica is a well-known foodborne pathogen causing gastrointestinal infections worldwide. The strain Y. enterocolitica FORC_002 was isolated from the gill of flatfish (plaice) and its genome was sequenced. The genomic DNA consists of 4,837,317 bp with a GC content of 47.1%, and is predicted to contain 4,221 open reading frames, 81 tRNA genes, and 26 rRNA genes. Interestingly, genomic analysis revealed pathogenesis and host immune evasion-associated genes encoding guanylate cyclase (Yst), invasin (Ail and Inv), outer membrane protein (Yops), autotransporter adhesin A (YadA), RTX-like toxins, and a type III secretion system. In particular, guanylate cyclase is a heat-stable enterotoxin causing Yersinia-associated diarrhea, and RTX-like toxins are responsible for attachment to integrin on the target cell for cytotoxic action. This genome can be used to identify virulence factors that can be applied for the development of novel biomarkers for the rapid detection of this pathogen in foods.

• 한국응용곤충학회지
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• 제51권4호
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• pp.377-382
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• 2012

경기지역에서 담배가루이의 발생 및 약제반응을 조사하였다. 담배가루이는 13개 시군에서 발생되었으며, 유전자(16S rRNA, MtCOI) 분석결과, 고양시 일부지역은 biotype B와 Q가 혼재되었으나, 그 밖의 지역에서 2005부터 국내 발생이 보고되었던 biotype Q로 나타났다. 채집곤충 및 기주식물의 total DNA에 대해 PCR을 통한 염기서열 분석과 southern hybridization 분석 결과 모든 지역에서 Tomato Yellow Leaf Curl Virus(TYLCV)는 검출되지 않았다. 5개 지역에서 채집한 6 개체군의 담배가루이를 실내사육하면서 유묘검정법으로 성충에 대한 살충제 감수성을 검정한 결과, 지역별로 다소 차이는 있었지만 네오니코티노이드계 약제의 경우 biotype B에게 높은 살충활성을 나타낸 반면 biotype Q에게는 상대적으로 낮은 살충활성을 나타내었다.

• 한국균학회지
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• 제48권3호
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• pp.337-343
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• 2020

한국에서 식물병원성 균류의 생물다양성을 파악하기 위한 균류 탐사를 통하여 에키나시아 흰가루병이 지속적으로 관찰되었다. 총 9점의 시료를 고려대학교 식물표본보관소에 보존하였다. 병든 식물에서는 주로 성엽에서 흰색의 얇은 균사층이 전면으로 또는 부분적으로 나타났다. 흰가루병균의 감염으로 줄기와 꽃잎에서는 변색 부위가 나타나는 특징을 보였다. 이 흰가루병균 무성세대의 형태적 특징과 더불어 ITS 및 LSU 염기서열을 계통분석한 결과, 이 흰가루병균은 Podosphaera xanthii로 동정되었다. 이는 한국에서 에키나시아 흰가루병에 관한 최초의 보고이다.

• Mycobiology
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• 제48권4호
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• pp.288-295
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• 2020

Species of Laccaria (Hydnangiaceae, Agaricales, and Basidiomycota) are well-known ectomycorrhizal symbionts of a broad range of hosts. Laccaria species are characterized by brown, orange, or purple colored basidiocarps, and globose or oblong, echinulate and multinucleate basidiospores. While some Laccaria species are easily identified at the species level using only the morphological characteristics, others are hard to distinguish at the species level due to small differences in morphology. Heretofore, ten Laccaria species have been reported in Korea. While studying the fungal diversity in the National Parks of Korea, two new Laccaria species were discovered. Species identification was done based on molecular analyses (ITS, 28S rDNA, rpb2, and tef1), then were confirmed by their corresponding morphologies. The two newly discovered Laccaria species are proposed here as Laccaria macrobasidia and Laccaria griseolilacina. The unique morphological characters of L. macrobasidia that distinguish it from its closely related species are orange-brown colored basidiocarp, long basidia and the absence of cheilocystidia. L. griseolilacina is characterized by a light grayish lavender-colored pileus and the absence of cheilocystidia. Two new species are described and illustrated in the present paper.

• 식물병연구
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• 제27권3호
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• pp.115-119
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• 2021

2020년 경상북도 포항군 연일읍의 갯기름나물 재배 농가포장에서 잎에 작은 갈색 반점이 형성되고 잎끝부터 갈변되며 고사하는 증상이 발생하였다. 균총은 흰색에서 연한 회색을 띠었다. 균핵은 검은색의 구형 또는 타원형이었다. 자낭반은 컵모양이며, 크기는 0.5-0.9 cm이었다. 자낭은 원통형이고 크기는 75-240×5.9-17.3 ㎛이었다. 자낭포자는 무색의 타원형이었으며 크기는 8.4-10.7×4.8-5.8 ㎛이었다. Internal transcribed spacer (ITS) 1과 ITS4 영역의 염기서열 분석결과 Sclerotinia sclerotiorum과 100% 일치하였으며, 이와 같은 병원균의 균학적 특징, 병원성 검정 결과 그리고 염기서열 분석결과를 바탕으로 갯기름나물 잎반점과 마름 증상의 원인균은 S. sclerotiorum으로 동정하였으며, 이 병을 갯기름나물 균핵병으로 명명할 것을 제안한다.