• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.1057-1062
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• 2004

The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. Insecticidal proteins, coded by genes located in plasmids, form typical parasporal, crystalline inclusions during sporulation. We isolated a Bacillus thuringiensis strain having insecticidal activity against larvae of the house fly (M. domestica) from the soils at a pig farm in Korea, and named it Bacillus thuringiensis SM. The culture filtrate from Bacillus thuringiensis SM showed strong lethality (83.3%) against M. domestica larvae. The parasporal crystal is enclosed within the spores' outermost envelope, as determined by transmission electron microscopy, and exhibited a bipyramidal form. The crystal proteins of strain SM consisted of five proteins with molecular weights of approximately ~130, ~80, ~68, ~42, and ~27 kDa on a 10% SDS-PAGE (major band, a size characteristic of Cry protein). Examination of antibiotic resistance revealed that the strain SM showed multiple resistant. The strain SM had at least three different plasmids with sizes of 6.6, 9.3, and 54 kb. Polymerase chain reactions (PCRs) revealed the presence of cry1, cry4A2, and cry11A1 genes in the strain SM. The cry1 gene profile of the strain SM appeared in the three respective products of 487 bp [cry1A(c)], 414 bp [cry1D], and 238 bp [cry1A(b)]. However, the strain SM has not shown the cry4A2 md cry11A1 genes. In in vivo toxicity assays, the strain SM showed high toxicity on fly larvae (M. domestic) [with $LC_{50}$ of 4.2 mg/ml, $LC_{90}$ of 8.2 mg/ml].

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.507-513
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• 2017

Bacillus subtilis spores can be used for protein display to engineer protein properties. This method overcomes viability and protein-folding concerns associated with traditional protein display methods. Spores remain viable under extreme conditions and the genotype/phenotype connection remains intact. In addition, the natural sporulation process eliminates protein-folding concerns that are coupled to the target protein traveling through cell membranes. Furthermore, ATP-dependent chaperones are present to assist in protein folding. CotA was optimized as a whole-cell biocatalyst immobilized in an inert matrix of the spore. In general, proteins that are immobilized have advantages in biocatalysis. For example, the protein can be easily removed from the reaction and it is more stable. The aim is to improve the pH stability using spore display. The maximum activity of CotA is between pH 4 and 5 for the substrate ABTS (ABTS = diammonium 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate). However, the activity dramatically decreases at pH 4. The activity is not significantly altered at pH 5. A library of approximately 3,000 clones was screened. A E498G variant was identified to have a half-life of inactivation ($t_{1/2}$) at pH 4 that was 24.8 times greater compared with wt-CotA. In a previous investigation, a CotA library was screened for organic solvent resistance and a T480A mutant was found. Consequently, T480A/E498G-CotA was constructed and the $t_{1/2}$ was 62.1 times greater than wt-CotA. Finally, E498G-CotA and T480A/E498G-CotA yielded 3.7- and 5.3-fold more product than did wt-CotA after recycling the biocatalyst seven times over 42 h.

• Journal of Microbiology and Biotechnology
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• 제3권3호
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• pp.146-155
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• 1993

A DNA fragment from an alkali-tolerent Bacillus sp., conferring strong promoter activity, was subcloned into the promoter probe plasmid pPL703 and the nucleotide sequence of this promoter region was determined. The sequence analysis suggested that this highly efficient promoter region containing the complex clustered promoters comprised three kinds of promoters (P1, P2 and P3), which are transcribed by $\sigma^B (formerly \sigma^{37}), \sigma^E(formerly \sigma^{29}) and \sigma^A (formerly \sigma^{43})$ RNA polymerase holoenzymes which play major rules at the onset of endospore formation, during sporulation and at the vegetative phase of growth, respectively. S1 nuclease mapping experiments showed that all three promoters had staggered transcription initiation points. The results of chloramphenicol acetyltransferase assay after the subcloning experiments also indicated that the expression of these clustered promoters was correlated with the programs of growth and endospore development. Promoter P1, P2 and P3 were preceded by 75% AT, 79% AT and 81% AT regions, respectively, and a partial deletion of AT-rich region prevented transcription from promoter P1 in vivo. Two sets of 5 -AGTGTT-3 sequences and inverted repeat sequences located around the promoter P1 were speculated as the possible cis acting sites for the catabolite repression in B. subtilis. In vivo transcripts from these sequence regions may be able to form a secondary structure, however, the possibility that a regulatory protein induced by the excess amount of glucose could be bound to such a domain for crucial action remains to be determined.

• 한국균학회지
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• 제22권2호
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• pp.172-183
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• 1994

접합내생균근 균(AMF)이 있는 토양을 이용하여 여러 종류의 비료를 주면서 식물을 재배하여, AMF포자 증식에 대하여 관찰하였다. 식물뿌리에서 AM화된 뿌리는 여러가지 형태가 현미경 관찰을 통하여 확인되었으며, 정상적인 Vesicles, Arbuscles 및 sporulation 과정도 관찰되었으며, 꽃송이와 같은 특수한 형태도 관찰되었다. 포자증식에 있어서의 80일간의 관찰과 뿌리염색을 통한 뿌리감염도의 관찰결과, 40일 주기로 포자의 생산에 증감이 주기적으로 일어나는 것을 관찰하였다. 비료를 첨가한 토양에서 수수, 파, 고추 및 차풀의 순으로 포자 증식에 좋은식물로 나타났으며, 그 포자 증식이 조건에 따라 다양하게 나타났다. 비료의 첨가에서는 인산이 없는 비료에서 포자증식이 크게 일어났으며, 21-17-17 비료에서는 포자증식 적었다. 식물별로 본다면, 수수, 고추, 파등의 순으로 포자증식이 많이 되었다.

• 한국균학회지
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• 제15권2호
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• pp.92-98
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• 1987

느타리버섯 볏짚배지(培地)에 발생하는 유해균류(有害菌類)를 조사하고 그중 발생(發生) 및 피해(被害)가 큰 균류(菌類)의 배양적(培養的) 성질에 관한 실험을 실시한 결과를 요약하면 다음과 같다. 1. 느타리버섯 볏짚배지(培地)에서 12종류(種類)의 진균류(眞菌類)가 분리(分離)되었는데 그 중 Trichoderma, Aspergillus, Rhizopus 등은 발생빈도(發生頻度)가 높고 발생양(發生量)도 많았다. 2. 느타리버섯 볏짚배지(培地)에서는 7종(種)의 Trichoderma가 동정되었는데 발생빈도(發生頻度)는 T. pseudokoningii, T. aureoviride, T. viride, T. harzianum, T. koningii의 順이었다. 3. 유해균류(有害菌類)의 발생(發生)은 일반 버섯재배사(栽培舍)에서 재배회수(栽培回數)가 증가(增加)할수록 많았고 추기재배(秋期栽培)보다는 춘기재배(春期栽培)에서 심하였다. 4. 볏집추출배지(抽出培地) 및 느타리버섯 추출배지(抽出培地)에서 Trichoderma, Aspergillus, Rhzopus 등 공시한 균들의 균사생장과 분생포자의 형성이 양호한 결과를 보이므로서 볏짚배지(培地) 및 균상(菌床)의 버섯과 그 파열물들이 균류(菌類)의 발생(發生)에 알맞는 조건을 부여하였다. 5. Trichoderma spp.는 톱밥추출배지(抽出培地) 및 미강추출배지(米糠抽出培地)에서 생장(生長)이 극히 양호하여 균상(菌床)에 접종(接種)한 종균(種菌)은 균류(菌類)의 배지(培地)가 되었다.

• 한국응용곤충학회지
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• 제4권
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• pp.25-28
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• 1965

본 병은 그 병징이 종래에 알려진 일반 묘썩음병과는 달리 검은빛 균사가 수중의 종자표면을 뒤덮어 자라면서 종자표면을 흑변시킬 뿐만 아니라, 종자의 주위토양까지도 흑변시켰으며, 발아한 종자는 최고 3cm 이상은 자라지도 못하고 흑변하여 부패하였다. 병원균은 자연상태에서나 인공배양기상에서나 포자를 형성하지 않았으며, 균사는 현미경하에서 암색을 띄었고 뚜렷한 격막을 갖고 있었다. 따라서 종래의 벼모썩음병 병원균의 대부분이 Phycomysetes에 속했으나 본병원균은 불완전균을 닮아 있었으며, 앞으로 그 구명을 위한 계속적인 연구가 필요했다. 본병의 발병환경은 모든 면에서 종래의 벼 모썩음병과 거의 동일했으며, 특히 종자가 발아할 때의 환경조건이 절대적인 영향을 미쳤다. 본병균은 종자를 통해서 전염되는 경우는 없었으며, 오직 감염된 토양에 의해서만 전염된다는 것을 알 수 있었다.

• 농업과학연구
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• 제10권2호
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• pp.269-276
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• 1983

전국(全國)에서 수집(收集)한 50개(固) 참깨종자(種子) sample을 blotter법(法)으로 조사(調査)하였던 바 Alternaria sesami는 29개(固) sample에서 최고(最高) 37%, Corynespora cassiicola는 38개(固) sample에서 최고(最高) 76%의 높은 비율(比率)로 검출(檢出)되었다. A. sesami와 C. cauiicola에 각각(各各) 심(甚)하게 이병(罹病)된 종자(種子)는 종자부패(種子腐敗)를 일으켜 전혀 발아(發芽)하지 못하며 일부(一部) 이병(罹病)된 종자(種子)는 발아(發芽)하더라도 곧 유묘감염(幼苗感染)이 되어 유근(柳根)이나 자엽(子葉)의 일부(一部)가 갈변(褐變)하며 고사(枯死)하였다. 종자전염성(種子傳染性) A. sesami와 C. cassiicola에 대(對)한 몇가지 종자소독제(種子消毒劑)의 효과(效果)를 조사(調査)하였던 바 A. sesami의 종자감염(種子感染)에 대(對)하여는 Busan 30의 소독효과(消毒效果)가 높았고 C. cassiicola의 종자감염(種子感染)에 대(對)하여는 Benlate T와 Homai의 소독효과(消毒效果)가 탁월(卓越)하였다.

• 한국응용곤충학회지
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• 제20권1호
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• pp.37-41
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• 1981

콩의 흑색뿌리썩음병을 일으키는 Cylindrocladium crotalariae은 감자한천배지와 콩의 조직을 함유한 한천 배지를 서로 다르게 Water potential를 조절하여 이 병원균을 접종한 결과 균사신장과 대형분생포자형성은 -14bars에서 좋았고 $30^{\circ}C$에서는 -100bars $25^{\circ}C$에서는 -80bars $20^{\circ}C$에서는 -64bars에서 균사신장이 중지되었으며 포자형성도 -64bars에서 중지되었다. 자낭각과 미소균핵형성은 소금을 첨가하지 않은 -1.4나 -3.0bars에서 잘 되었고 이 균에 대한 포자발아율은 -1.4bars에서 -20bars의 모든 Water potential에서 똑 같이 좋았고 -20bars에서 Water potential이 낮아지므로 발아율이 떨어지다가 -60bars에서 억제되었다.

• The Plant Pathology Journal
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• 제33권3호
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• pp.329-336
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• 2017

An experiment was conducted to evaluate the tolerance of micropropagated and mycorrhized alpinia plants to the parasite Meloidogyne arenaria. The experimental design was completely randomized with a factorial arrangement of four inoculation treatments with arbuscular mycorrhizal fungi (AMF) (Gigaspora albida, Claroideoglomus etunicatum, Acaulospora longula, and a non-inoculated control) in the presence or absence of M. arenaria with five replicates. The following characteristics were evaluated after 270 days of mycorrhization and 170 days of M. arenaria inoculation: height, number of leaves and tillers, fresh mass of aerial and subterranean parts, dry mass of aerial parts, foliar area, nutritional content, mycorrhizal colonization, AMF sporulation, and the number of galls, egg masses, and eggs. The results indicated a significant interaction between the treatments for AMF spore density, total mycorrhizal colonization, and nutrient content (Zn, Na, and N), while the remaining parameters were influenced by either AMF or nematodes. Plants inoculated with A. longula or C. etunicatum exhibited greater growth than the control. Lower N content was observed in plants inoculated with AMF, while Zn and Na were found in larger quantities in plants inoculated with C. etunicatum. Fewer galls were observed on mycorrhized plants, and egg mass production and the number of eggs were lower in plants inoculated with G. albida. Plants inoculated with A. longula showed a higher percentage of total mycorrhizal colonization in the presence of the nematode. Therefore, the association of micropropagated alpinia plants and A. longula enhanced tolerance to parasitism by M. arenaria.

• BMB Reports
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• 제44권5호
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• pp.323-328
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• 2011

We screened four B. thuringiensis strains whose parasporal inclusions contained the S-layer protein (SLP), and cloned two slp genes from each strain. Phylogenetic analysis indicated these SLPs could be divided into two groups, SLP1s and SLP2s. To confirm whether SLPs were present in the S-layer or as a parasporal inclusion, strains CTC and BMB1152 were chosen for further study. Western blots with isolated S-layer proteins from strains CTC and BMB1152 in the vegetative phase showed that SLP1s and SLP2s were constituents of the S-layer. Immunofluorescence utilizing spore-inclusion mixtures of strains CTC and BMB1152 in the sporulation phase showed that SLP1s and SLP2s were also constituents of parasporal inclusions. When heterogeneously expressed in the crystal negative strain BMB171, four SLPs from strains CTC and BMB1152 could also form parasporal inclusions. This temporal and spatial expression is not an occasional phenomenon but ubiquitous in B. thuringiensis strains.