• 한국균학회지
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• 제28권2호
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• pp.81-87
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• 2000

곤충을 기주로 하여 자실체를 형성하는 곤충기생균(entomopathogenic fungi)의 일종인 풍뎅이동충하초(Cordyceps scarabaeicola Kobayasi)는 풍뎅이상과(Scarabaeoidea)의 성충을 기주로 하여 자실체를 형성한다(Evans, 1982; Evans and Samson 1982; Humber(unpublished); Kobayasi, 1940). 풍뎅이동충하초(C. scarabaeicola)는 자낭균아문(Ascomycotina), 핵균강(Pyrenomycetes)의 맥각균목(Clavicipitales), 동충하초과(Cordycipiteae), 동충하초속(Cordyceps)에 속하며 한국을 비롯하여 중국, 일본 등 전 세계적으로 분포한다(Dennis, 1981; Sung, et al, 1997; 청수. 1981). 또한 이(1996)는 풍뎅이동충하초의 불완전세대는 Beauveria속의 분생포자를 형성한다고 보고하였다. 풍뎅이동충하초는 MCM에서 잘 생장하나 균사밀도는 PDA배지가 가장 적합한 것으로 나타나 다른 버섯균과는 별다른 차이를 보이지 않았으며 온도는 $25^{\circ}C$가 가장 좋았으며 pH는 $7.5{\sim}9.0$으로 균주에 따라 차이를 보였다. 이러한 결과는 이(1996)의 연구결과인 PD배지와 $24^{\circ}C$에서 우수한 균사생장을 보였고 $30^{\circ}C$에서는 약간의 균사생장이 억제되었고, pH $8{\sim}9$의 알카리성 범위에서 우수한 균사생장을 보였다는 보고와 거의 일치함을 보였다. 풍뎅이동충하초는 탄소원을 첨가하지 않은 것에서 균사생장이 가장 높게 나타났지만 균사밀도는 가장 낮게 나타났다. 균사생장과 밀도는 lactose가 적합한 탄소원으로 나타났으며, 질소원은 ammonium phosphate에서 높은 균사생장을 보여 모두 무기태 질소원에서 우수함을 보였다.

• Mycobiology
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• 제29권3호
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• pp.121-131
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• 2001

This study was carried out to identify the phylogenetic relationships among several caterpillar fungi by comparing the sequences of internal transcribed spacer regions(ITS1 and ITS2) and 5.8S ribosomal DNA(rDNA) repeat unit. The sequences of ITS1, ITS2, and the 5.8S rDNA from 10 strains of Cordyceps species, 12 strains of Paecilomyces, 3 strains of Beauveria, 2 strains of Metarhizium and 1 strains of Hirsutella were amplified, determined and compared with the previously known Cordyceps species. The sequences of 5.8S rDNA were more conserved in length and variation than those of ITS regions. Although the variable ITS sequences were often ambiguously aligned, the conserved sites could be found. In the phylogenetic tree, the species generally divided into three clusters, supported by their morphology and/or host ranges. The 5.8S rDNA and TTS1 sequences among 10 species of Cordyceps militaris were identical and only one base pair in ITS2 sequence was different. Cordyceps sinensis and Cordyceps ophioglossoides were also clearly different, although they belonged to the same cluster. The Geniank database search of species revealed sister taxa of an entomogenous fungus. Metarhizium was used as an putgroup in all taxa.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1979년도 춘계학술대회
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• pp.113.2-114
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• 1979

$\beta-Galactosidase$ is an enzyme which catalizes hydrolysis of lactose, a natural substrate, to glucose and galctose and transferring some monosac-charide units to active acceptors as sugar or alcohol. The occurence of $\beta-Galactosidase$ is known in various microorganisms, animals and higher plants and has been studied by many investigatigators. Especially, a great deal of articles for the enzyme of E. coli have been presented in genetic control mechanism and induction-repression effects of proteins, On the other hand, in the dairly products industry, it is important to hydrolyes lactosd which is the principal sugar of milk and milk products. During the last few years, the interest in enzymatic hydrolysis of milk lactose has teen increased, because of the lactose intolerence in large groups of the population. Microbial $\beta-Galactosidases$ are considered potentially most suitable for processing milk to hydrolyse lactose and, in recent years, the immobilized enzyme from yeast has been examined. Howev, most of the microbial $\beta-Gal$ actosidase are intracellular enzymes, except a few fungal $\beta-Gala-$ ctosidases, and extracellular $\beta-Galactosidase$ which may be favorable to industrial applieation is not so well investigated. On this studies, a mold producing a potent extracellular $\beta-Galactosidase$ was isolated from soil and identified as an imperfect fungus, Beauveria bassians. In this strain, both extracellular and intracellular $\beta-Galactosidases$ were produced simultaneously and a great increase of the extracellular production was acheved by improving the cultural conditions. The extracellular enzyme was purified more than 1, 000 times by procedures including Phosphocellulose and Sephadex G-200 chromatographies. Several characteristics of the enzymewas clarified with this preparation. The enzyme has a main subunit of molecular weight of 80, 000 which makes an active aggregate. And at neutral pH range, it has optimum pH for activity and stability. The Km value was determined to be 0.45$\times$10$^{-3}$ M for $o-Nitrophenyl-\beta-Galactoside.$ In any event, it is interesting to sttudy the $\beta-Galactosidase$ of B. bassiana for the mechanism of secretion and conformational structure of enzyme.

• 생명과학회지
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• 제13권4호
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• pp.400-411
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• 2003

5.8S rDNA를 포함한 ITS부위에 대한 염기서열 분석결과, 종에 따라 다양한 염기서열을 가지고 있어 분류에 이용될 수 있었으며, 특히 ITS2부위보다 ITS1부위에서 종에 대한 변이율이 높은 것으로 나타났다. 아울러 균종에 따라 정도의 차이는 있으나 사용된 모든 종들이 서로 계통분류학적 거리가 멀어서 종간의 구분이 명확하게 나타났다. P. tenuipes, I. japonica, P. japonicus는 multiple alignment분석에서 매우 유사한 염기서열을 가지고 있어, 이들 세종은 같은 종이지만 다른 이름으로 불리고 있는 것으로 나타났으며, 아울러 Paecilomyces sp. KACC 40220과 KACC 40656도 동일한 염기서열을 가지고 있어 p. tenuipes로 판단된다. 국내에서 유통되는 동충하초제품 35건과 중국산 1건에 대해 실험한 결과 23건은 P. tenuipes / japonica로, 11건은 C. militaris로, 1건은 B. bassiana로 분류되었으며, 중국산 제품 1건은 C. multiaxialis로 분류되었다.

• 대한본초학회지
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• 제35권2호
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• pp.47-53
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• 2020

Objectives : Bombyx batryticatus L. is the dried larval form of the silkworm (Bombyx mori L.) infected by Beauveria bassiania (Bals.) Vuill. It is used as a food and medicinal resource to treat asthma, headaches, epilepsy, and convulsions in traditional Korean and Chinese medicines. However, the research of the toxicity about B. batryticatus is not enough yet. Here, we investigate the effects of potential subacute toxicity following the repeated oral administration of B. batryticatus water extract to C57BL/6 mice, at various doses of 0, 50, 150, and 450 mg/kg/day during a two-week period. Methods : The following parameters were examined during the study period: body weight, gross findings, clinical signs, organ weight, hematology, serum biochemistry, histopathology, and mortality. At the end of the treatment period, all the mice were euthanized. Results : No changes were observed in the body weights, gross findings, clinical signs, organ weights, and mortality after two weeks of administration of the B. batryticatus extract. In addition, compared with the normal control group, no noticeable treatment-related changes were observed in the hematological, serum biochemical, and histopathological parameters in the treated group following treatment with doses of up to 450 mg/kg/day. Conclusion : Based on these findings, we conclude that the treatment of mice with the water extract of B. batryticatus did not cause considerable C57BL/6 toxicity, and therefore, it could be considered safe for further pharmacological studies.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 춘계학술대회 및 임시총회
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• pp.27-28
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• 2014

Beauveria bassiana (Cordycipitaceae, Hypocreales, Ascomycota) is an anamorphic fungus having a potential to be used as a biological control agent because it parasitizes a wide range of arthropod hosts including termites, aphids, beetles and many other insects. A number of bioactive secondary metabolites (SMs) have been isolated from B. bassiana and functionally verified. Among them, beauvericin and bassianolide are cyclic depsipeptides with antibiotic and insecticidal effects belonging to the enniatin family. Non-ribosomal peptide synthetases (NRPSs) play a crucial role in the synthesis of these secondary metabolites. NRPSs are modularly organized multienzyme complexes in which each module is responsible for the elongation of proteinogenic and non-protein amino acids, as well as carboxyl and hydroxyacids. A minimum of three domains are necessary for one NRPS elongation module: an adenylation (A) domain for substrate recognition and activation; a tholation (T) domain that tethers the growing peptide chain and the incoming aminoacyl unit; and a condensation (C) domain to catalyze peptide bond formation. Some of the optional domains include epimerization (E), heterocyclization (Cy) and oxidation (Ox) domains, which may modify the enzyme-bound precursors or intermediates. In the present study, we analyzed genomes of B. bassiana and its allied species in Hypocreales to verify the distribution of NRPS-encoding genes involving biosynthesis of beauvericin and bassianolide, and to unveil the evolutionary processes of the gene clusters. Initially, we retrieved completely or partially assembled genomic sequences of fungal species belonging to Hypocreales from public databases. SM biosynthesizing genes were predicted from the selected genomes using antiSMASH program. Adenylation (A) domains were extracted from the predicted NRPS, NRPS-like and NRPS-PKS hybrid genes, and used them to construct a phylogenetic tree. Based on the preliminary results of SM biosynthetic gene prediction in B. bassiana, we analyzed the conserved gene orders of beauvericin and bassianolide biosynthetic gene clusters among the hypocrealean fungi. Reciprocal best blast hit (RBH) approach was performed to identify the regions orthologous to the biosynthetic gene cluster in the selected fungal genomes. A clear recombination pattern was recognized in the inferred A-domain tree in which A-domains in the 1st and 2nd modules of beauvericin and bassianolide synthetases were grouped in CYCLO and EAS clades, respectively, suggesting that two modules of each synthetase have evolved independently. In addition, inferred topologies were congruent with the species phylogeny of Cordycipitaceae, indicating that the gene fusion event have occurred before the species divergence. Beauvericin and bassianolide synthetases turned out to possess identical domain organization as C-A-T-C-A-NM-T-T-C. We also predicted precursors of beauvericin and bassianolide synthetases based on the extracted signature residues in A-domain core motifs. The result showed that the A-domains in the 1st module of both synthetases select D-2-hydroxyisovalerate (D-Hiv), while A-domains in the 2nd modules specifically activate L-phenylalanine (Phe) in beauvericin synthetase and leucine (Leu) in bassianolide synthetase. antiSMASH ver. 2.0 predicted 15 genes in the beauvericin biosynthetic gene cluster of the B. bassiana genome dispersed across a total length of approximately 50kb. The beauvericin biosynthetic gene cluster contains beauvericin synthetase as well as kivr gene encoding NADPH-dependent ketoisovalerate reductase which is necessary to convert 2-ketoisovalarate to D-Hiv and a gene encoding a putative Gal4-like transcriptional regulator. Our syntenic comparison showed that species in Cordycipitaceae have almost conserved beauvericin biosynthetic gene cluster although the gene order and direction were sometimes variable. It is intriguing that there is no region orthologous to beauvericin synthetase gene in Cordyceps militaris genome. It is likely that beauvericin synthetase was present in common ancestor of Cordycipitaceae but selective gene loss has occurred in several species including C. militaris. Putative bassianolide biosynthetic gene cluster consisted of 16 genes including bassianolide synthetase, cytochrome P450 monooxygenase, and putative Gal4-like transcriptional regulator genes. Our synteny analysis found that only B. bassiana possessed a bassianolide synthetase gene among the studied fungi. This result is consistent with the groupings in A-domain tree in which bassianolide synthetase gene found in B. bassiana was not grouped with NRPS genes predicted in other species. We hypothesized that bassianolide biosynthesizing cluster genes in B. bassiana are possibly acquired by horizontal gene transfer (HGT) from distantly related fungi. The present study showed that B. bassiana is the only species capable of producing both beauvericin and bassianolide. This property led to B. bassiana infect multiple hosts and to be a potential biological control agent against agricultural pests.

• 한국유기농업학회지
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• 제20권1호
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• pp.49-58
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• 2012

무농약 재배 토마토에서 발생이 많은 온실가루이를 방제하기 위해 유기농자재를 이용하여 방제한 결과와 천적 방사시기 및 천적과 유기농자재를 적절하게 이용하기 위해 유기농 자재가 담배장님노린재에 미치는 영향을 조사한 결과는 다음과 같다. 친환경농자재를 1주 간격 3회 연속 살포하면 $Beauveria$ $bassiana$, 고삼추출물, 제충국추출물, 멀구슬+고삼추출물, 고삼+계피추출물, 고삼추출물2가 70% 이상의 방제가를 보였다. 온실가루이 밀도가 높아진 이후 담배장님노린재를 방사하면 정착이 잘 되지 않아 방제가가 59.7%로 낮아 발생초기인 정식 1주일째부터 방사한 경우 5주째에 방제가가 90.8%로 높게 나타나 온실가루이를 방제할 수 있었다. 친환경 자재의 살포 방법별 담배장님노린재의 살충율은 살포 직후나 살포 후 약액이 다 마른 이후 천적을 방사하는 경우 살충율이 아주 낮았으나 방사이후 자재를 살포하면 67.7-70.5%의 살충율을 나타내므로 주의가 필요하였다. 그러나 해충인 온실가루이가 방제가 된 이후 담배장님노린재의 밀도가 급격히 증가하여 해충화 될 경우에는 멀구슬+고삼추출물과 제충국추출물, 고삼추출물을 살포할 필요가 있었다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2016년도 춘계학술대회 및 임시총회
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• 한국잠사곤충학회지
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• 제43권2호
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• pp.83-87
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• 2001

현재까지 곤충기생균 고유배지가 개발되어 있지 않아 식물기생균 배지를 대체 이용해 옴에 따라, 본 시험에서는 고단백질원으로써 이용가치가 있는 누에분말을 이용하여 곤충기생균 최적배지를 개발코자 하였다. 그 결과 사면배지상에서 균 배양시 12종의 배양형태는 현상, 융기, 주변형태가 균종 및 배지에 따라 배양 상이 동일 혹은 다양하게 형성되었다. 균주별 생장율은 12균주 중 C. militaris를 제외한 11 균주가 SLA배지에서 PDA에 비해 대부분의 균생장이 양호하였으나 C. militaris는 기존배지와 비교해 생장률이 78.6%로 감소하였다. Dextrose 첨가시 최적 농도는 C. gracilioides등 6균주에서 6% 처리시 가장 높은 생장률을 나타내었다. 본 시험결과 선발된 배지로부터 배양균을 누에접종 후 재배 시험한 결과 감염율, 자실체 형성을, 분생자경수 및 분생자경의 길이는 91.3$\pm$1.5%, 88.6$\pm$2.3%, 56.6$\pm$3.2개, 33.4$\pm$2.8mm로 대조에 비해 모두 높게 나타났다. 본 시험에서 개발된 Dextrose를 첨가한 SLA-A배지의 경제성 분석결과 1ι생산시 기존배지가 6,261원이 소요되는 것에 비해 총 2,386원으로 생산이 가능해 본 배지로 대체시 61.9%의 절감효과를 나타내었다.