• 한국응용곤충학회지
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• 제5_6권
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• pp.19-26
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• 1968

휴지상태에 있는 성숙한 도열병균 포자 1,000개를 관찰한 결과 각 세포에 단핵을 가지는 포자비율이 $95\%$로 단연 많았고 또 미숙회자인 1세포 1핵 포자로부터 출발하여 3세포 3핵인 성숙포자가 형성됨을 관찰할 수 있었다. 분열 중인 핵은 배열된 염색체로서 관찰할 수 있었으며, 염색체수는 n=3,4,5,6개로 나타났으나, n=5개가 가장 많았다. 핵이 발아관으로 이동하는 방법은 첫째로 휴지상태에 있던 핵이 분열하여 2핵이 되고 그 중 1핵이 발아관에 이동하고 1핵은 세포내에 머무는 것과$(43\%)$, 둘째 방법은 핵분열 없이 직접 세포내의 1핵이 발아관을 따라 이동하는 것들이 $(57\%)$ 있다. 또 부착기내의 핵을 염색하여 관찰한 결과 무핵의 부착기가 상당히 많았으나 핵질을 가진 500개의 부착기 중에 단핵이 476개로서 $95.2\%$였다(Chromosome 으로 관찰된 4부착기는 제외). 이상의 결과로서 도열병균은 전생활환을 통하여 단핵을 함유한다는 것을 인정할 수 있으며, 도열병균포자가 다세포일지라도 Homokaryon이라고 생각되므로 단포자분리균을 도열병에 관한 모든 시험에 공시하는 것은 합당하다고 할 수 있다.

• 한국응용곤충학회지
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• 제47권2호
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• pp.169-174
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• 2008

눈꽃동충하초균(Paecilomyces tenuipes)의 균사 및 포자 형성에 영향을 미치는 계대증식에서의 특성을 알아보기 위하여, 액체배지로써는 누에 유충분말이 함유된 SL배지와 일반적인 PD배지를 이용하였고, 고체배지로는 누에 번데기 분말을 넣은 현미배지상에서, 세대증식이 이루어진 각 균주에 대해서 조사하였다. 그 결과, 액체 배지에서의 포자 생산량은 세대에 따라 큰 차이를 보였으나, 현미배지에서의 포자 생성율은 세대간에 큰 차이를 보이지 않음으로써, 액체배지에서 계대증식이 고체배지에서의 포자생산량에는 큰 영향을 미치지 않는 것으로 나타났다. 또한 현미배지에 대한 최적 포자 접종량은 각각 $1{\times}10^{10}$ conidia/ml, $1{\times}10^6$ conidia/ml, $1{\times}10^6$ conidia/ml의 농도로 접종하였을 경우 농도에 따른 생산량에 차이가 나타나지 않아서 $1{\times}10^6$ conidia/ml만으로도 충분한 것으로 나타났다.

• 한국식물병리학회지
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• 제13권1호
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• pp.30-36
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• 1997

The effects of carbon and nitrogen sources on the mycelial growth and sporulation of microconidia and chlamydospores of five isolates of Cylindrocarpon destructans (Zinssm.) Scholten causing root rot of Panax ginseng were studied. For the carbon sources, fructose, glucose, maltose, and sucrose in Czapek-Dox broth showed good mycelial growth of 178∼201 mg in dry weight compared with 64 mg of the control. The best carbon sources tested for conidial formation were sucrose and maltose with 2.75 and 3.03 log conidia/ml, respectively. For the nitrogen sources, aspartic acid, NaNO3, KNO3, arginine, threonine, and leucine increased mycelial growth of the fungi to 208∼231 mg in dry weight without significant difference (p=0.05) among them. Meanwhile the growth with cystine was poor (26.3 mg dry weight), and no conidium and chlamydospore were formed. Maximum microconidial formation was observed in the media with NaNO3 and KNO3 as 3.37 and 3.35 log conidia/ml, and for the chlamydospore formation the (NH4)2SO4-containing medium and the nitrogen-absent medium were the best as 3.40 and 3.57 log chlamydospores/ml, respectively. No conidium was found in the medium without nitrogen sources, in which chlamydospore formation increased 6 times more than in the nitrogen-amended medium. However, deletion of carbon source in the medium did not affect on the formation of conidia and chlamydospores of C. destructans.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.15-15
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• 2014

Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes head blight of major cereal crops such as wheat, barley, and rice, as well as causing ear and stalk rot on maize worldwide. Plant diseases caused by this fungus lead to severe yield losses and accumulation of harmful mycotoxins in infected cereals [1]. Fungi utilize spore production as a mean to rapidly avoid unfavorable environmental conditions and to amplify their population. Spores are produced sexually and asexually and their production is precisely controlled. Upstream developmental activators consist of fluffy genes have been known to orchestrate early induction of condiogenesis in a model filamentous fungus Aspergillus nidulans. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we characterized functions of the F. graminearum fluffy gene homologs [2]. We found that FlbD is conserved regulatory function for conidiogenesis in both A. nidulans and F. graminearum among five fluffy gene homologs. flbD deletion abolished conidia and perithecia production, suggesting that FlbD have global roles in hyphal differentiation processes in F. graminearum. We further identified and functionally characterized the ortholog of AbaA, which is involved in differentiation from vegetative hyphae to conidia and known to be absent in F. graminearum [3]. Deletion of abaA did not affect vegetative growth, sexual development, or virulence, but conidium production was completely abolished and thin hyphae grew from abnormally shaped phialides in abaA deletion mutants. Overexpression of abaA resulted in pleiotropic defects such as impaired sexual and asexual development, retarded conidium germination, and reduced trichothecene production. AbaA localized to the nuclei of phialides and terminal cells of mature conidia. Successful interspecies complementation using A. nidulans AbaA and the conserved AbaA-WetA pathway demonstrated that the molecular mechanisms responsible for AbaA activity are conserved in F. graminearum as they are in A. nidulans. F. graminearum ortholog of Aspergillus nidulans wetA has been shown to be involved in conidiogenesis and conidium maturation [4]. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidia dormancy by suppressing microcycle conidiation in F. graminearum. In A. nidulans, FlbB physically interacts with FlbD and FlbE, and the resulting FlbB/FlbE and FlbB/FlbD complexes induce the expression of flbD and brlA, respectively. BrlA is an activator of the AbaA-WetA pathway. AbaA and WetA are required for phialide formation and conidia maturation, respectively [5]. In F. graminearum, the AbaA-WetA pathway is similar to that of A. nidulans, except a brlA ortholog does not exist. Amongst the fluffy genes, only fgflbD has a conserved role for regulation of the AbaA-WetA pathway.

• The Plant Pathology Journal
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• 제39권4호
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• pp.361-373
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• 2023

In plant-pathogen interactions, Magnaporthe oryzae causes blast disease on more than 50 species of 14 monocot plants, including important crops such as rice, millet, and most 15 recently wheat. M. oryzae is a model fungus for studying plant-microbe interaction, and the main source for fungal pathogenesis in the field. Here we report that MoJMJD6 is required for conidium germination and appressorium formation in M. oryzae. We obtained MoJMJD6 mutants (ΔMojmjd6) using a target gene replacement strategy. The MoJMD6 deletion mutants were delayed for conidium germination, glycogen, and lipid droplets utilization and consequently had decreased virulence. In the ΔMojmjd6 null mutants, global histone methyltransferase modifications (H3K4me3, H3K9me3, H3K27me3, and H3K36me2/3) of the genome were unaffected. Taken together, our results indicated that MoJMJD6 function as a nuclear protein which plays an important role in conidium germination and appressorium formation in the M. oryzae. Our work provides insights into MoJMJD6-mediated regulation in the early stage of pathogenesis in plant fungi.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.134-138
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• 1993

Monascus anka 732Y3 was induced from Monascus anka KFCC 11832 (IFO 4478, ATCC 16360) by ultra-violet light irradiation. The growth of this new fungus is frequently more dependent on sexual propagation than asexual propagation, compared with that of its parental strain, M. anka KFCC 11832. Less conidia than those of M. anka KFCC 11832 were observed by a microscope. The optical density of the red pigments ($OD_{500}$) produced by M. anka 732Y3 was 157, which was about 10 times higer than that of M. anka KFCC 11832. Such high production of the red pigments by the mutant could be explained by the following observations.

• Mycobiology
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• 제42권1호
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• pp.1-5
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• 2014

The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without forming mycelia. This phenomenon has been termed as microcycle conidiation, and to date has been reported in more than 100 fungal species. In this review, first, we present the morphological properties of fungi during microcycle conidiation, and divide microcycle conidiation into four simple categories, even though fungal species exhibit a wide variety of morphological differences during microcycle conidiogenesis. Second, we describe the factors that influence microcycle conidiation in various fungal species, and present recent genetic studies that have identified the genes responsible for this process. Finally, we discuss the biological meaning and application of microcycle conidiation.

• 한국동물위생학회지
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• 제30권2호
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• pp.283-286
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• 2007

Fungus generally doesn't produce toxic or harmful substances so it has low chances to cause food poisoning. However it leads to change appearance, odor and characteristics of the contaminated foods and result in sanitary risk problems. Therefore the contamination of fungi should be prevented since they are not proper for human consumption. Green fungi with white outline raised from the air cell of cooked eggs which were collected by Gyeongi Livestock Veterinary Service in August, 2006. The results came out after the cultivation using Sabouraud's Dextrose Agar(SDA). The conidium appeared white and monospore, the shape of colony was round and oval. Conidiophore was brown and granulated and wrinkles and formed. It was confirmed as Aspergillus nidulans based on the dying using Lactophenol cotton blue, the observation of septum and vesicle from the grown spores, and rDNA sequencing.

• Mycobiology
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• 제44권1호
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• pp.63-65
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• 2016

Cylindrocarpon destructans causes root rot disease in ginseng and can survive for a long time, producing chlamydospores. We optimized conditions to induce chlamydospore production from the conidia of C. destructans, isolated from Korean ginseng. This will provide the basis for testing the efficacy of control agents targeting these chlamydospores.

• 한국식물병리학회지
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• 제14권2호
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• pp.120-124
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• 1998

The conidial germination of Pestaotiopsis theae was occurred in cells attched with pedicels, the inferior cell of conidium. The cells were swollen like a ball, and then germinated in 4 hours under favorable conditions. Generally, it was considered that fifty percent of whole conidia was germinated in the range 6~12 hours. The optimum temperature and pH for conidial germination of P. theae (SP-3) causing leaf blight on sweet persimmon was $25^{\circ}C$ and pH 5, respectively. Conidial germination rate was higher than 90% at 100% relative humidity, but never germinated at a relative humidity lower than 88.5%. Conidial germination was highest at the concentration of 1~4$\times$104 conidia/ml. In case of cultural media, the conidial germination was higher than 90% on PDA, PSA, OME and Leonian agar. There was no relationship between light and conidial germination. It was concluded that the key environmental factors affecting conidial germination of the fungus (SP-3) were temperature and moisture.