• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.287-292
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• 2005

Hybrid시스템의 운전결과 황화수소의 removal efficiency는 황화수소의 inlet load가 $200g/m^{3}/h$에서 removal efficiency가 급격히 감소하여 약 60%의 수준을 유지하였다. 또한 톨루엔에 대한 removal efficiency는 거의 100%를 유지하다가 톨루엔의 inlet load가 $644g/m^{3}/h$로 증가할 때에는 약 60%로 감소하였다. 이와 같은 Hybrid시스템 운전결과로 부터 바이오필터만을 이용하여 황화수소와 톨루엔을 동시처리할 때보다 removal efficiency가 제고되었음이 관찰되었다.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1492-1495
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• 2008

Successful control of Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak, requires a specific and reliable diagnostic tool. A pathovar-specific PCR assay was developed for the rapid and accurate detection ofthe plant pathogenic bacterium Xanthomonas oryzae pv. oryzicola in diseased plant. Based on differences in a membrane fusion protein gene of Xanthomonas oryzae pv. oryzicola and other microorganisms, which was generated from NCBI (http://www.ncbi.nlm.nih.gov/) and CMR (http://cmr.tigr.org/) BLAST searches, one pair of pathovar-specific primers, XOCMF/XOCMR, was synthesized. Primers XOCMF and XOCMR from a membrane fusion protein gene were used to amplity a 488-bp DNA fragment. The PCR product was only produced from 4 isolates of Xanthomonas oryzae pv. oryzicola among 37 isolates of other pathovars and species of Xanthomonas, Pectobacterium, Pseudomonas, Burkholderia, Escherichia coli, and Fusarium oxysporum f.sp. dianthi. The results suggested that the assay detected the pathogen more rapidly and accurately than standard isolation methods.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1765-1771
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• 2007

A polymerase chain reaction (PCR)-based method was developed to detect the DNA of Ralstonia solanacearum, the causal agent of bacterial wilt in various crop plants. One pair of primers (RALSF and RALSR), designed using cytochrome c1 signal peptide sequences specific to R. solanacearum, produced a PCR product of 932 bp from 13 isolates of R. solanacearum from several countries. The primer specificity was then tested using DNA from 21 isolates of Ralstonia, Pseudomonas, Burkholderia, Xanthomonas, and Fusarium oxysporum f. sp. dianthi. The specificity of the cytochrome c1 signal peptide sequences in R. solanacearum was further confirmed by a DNA-dot blot analysis. Moreover, the primer pair was able to detect the pathogen in artificially inoculated soil and tomato plants. Therefore, the present results indicate that the primer pair can be effectively used for the detection of R. solanacearum in soil and host plants.

• Journal of Applied Biological Chemistry
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• 제63권2호
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• pp.125-129
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• 2020

Environmental pollution caused by various heavy metals is a serious global problem. To solve this problem, microbial bioremediation of contaminated metals has developed rapidly as an effective strategy when physical and chemical techniques are not suitable. In this study, cadmium (Cd)-tolerant soil bacteria were isolated via artificial induction in laboratory conditions instead of screening bacteria naturally adapted to metal-contaminated soils. Wild-type (WT) bacteria grown in uncontaminated soils were artificially and sequentially adapted to gradually increasing Cd concentrations of up to 15 mM. The resultant cells, named Soil-CdR15, survived at a Cd concentration of 10 mM, whereas WT cells failed to survive with 4 mM Cd on solid media for 2 d. In liquid media containing Cd, the SoilCdR15 cells grew with 15 mM Cd for 7 d, whereas the WT cells could not grow with 5 mM Cd. Both Soil-CdR15 and WT cells removed approximately 35% of Cd at the same capacity from liquid media containing either 0.5 or 1.0 mM Cd over 2 d. In addition to Cd, the Soil-CdR15 cells showed increased resistance to nickel, zinc, and arsenic compared to WT cells. The Soil-CdR cells were identified as Burkholderia sp. by partial sequencing of 16S rRNA. The data presented in this study demonstrate that isolation of heavy metal-tolerant microorganisms via artificial induction in laboratory conditions is possible and may be useful for the application of the microorganisms for the bioremediation of heavy metals.

• Journal of Microbiology
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• 제40권2호
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• pp.109-118
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• 2002

The present work is aimed at providing additional new pure cultures of oxalate utilizing bacteria and its preliminary characterization for further work in the field of oxalate-metabolism and taxonomic studies. The taxonomy of 14 mesophilic, aerobic oxalotrophic bacteria isolated by an enrichment culture technique from soils rhizosphers, and the juice of the petiole/stem tissue of plants was investigated. Isolates were characterized with 95 morphological, biochemical and physiological tests. Cellular lipid components and carotenoids of isolates were also studied as an aid to taxonomic characterization. All isolates were Gram-negative, oxidase and catalase positive and no growth factors were required. In addition to oxalates, some of the strains grow on methanol and/or formate. The taxonomic similarities among isolates, reference strains or previously reported oxalotrophic bacteria were analysed by using the Simple Matching (S/ sub SM/) and Jaccard (S$\_$J/) Coefficients. Clustering was performed by using the unweighted pair group method with arithmetic averages (UPGMA) algorithm. The oxalotrophic strains formed five major and two single-member clusters at the 70-86% similarity level. Based on the numerical taxonomy, isolates were separated into three phenotypic groups. Pink-pigmented strains belonged to Methylobacterium extorquens, yellow-pigmented strains were most similar to Pseudomonas sp. YOx and Xanthobacter autorophicus, and heterogeneous non-pigmented strains were closely related to genera Azospirillum, Ancylobacter, Burkholderia and Pseudomonas. New strains belonged to the genera Pseudomonas, Azospirillum and Ancylobacter that differ taxonomically from other known oxalate oxidizers were obtained. Numerical analysis indicated that some strains of the yellow-pigmented and nonpigmented clusters might represent new species.

• 식물병연구
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• 제17권1호
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• pp.38-43
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• 2011

채소류가 소비되기까지 약 10~30%에 이르는 양이 부패에 의해 버려지고 있다. 채소류는 수확 후 수많은 세균이나 곰팡이와 같은 다양한 미생물들에 의해 부패가 이루어진다. 채소류의 부패와 세균과의 관계를 알아보고자 세균의 다양성에 관한 조사를 하였다. 신선한 상추와 깻잎, 치커리에서의 총 호기성 균 수는 각각 $2.6{\sim}2.7{\times}10^6$, $4.6{\times}10^5$, $1.2{\times}10^6\;CFU/g$ of fresh weight이었으며, Pseudomonas spp., Alysiella spp., Burkholderia spp.와 그 외의 18개의 다양한 속들이 확인되었다. 신선한 채소류를 $28^{\circ}C$에서 일주일 동안 배양하였을 때 세균 다양성에 변화가 생겼다. 총 호기성 균의 수는 상추와 깻잎, 치커리에 대하여 각각 $1.1{\sim}4.6{\times}10^8$, $4.9{\times}10^7$, $7.6{\times}10^8\;CFU/g$ of fresh weight로 나타났으며, 이는 약 $10^2$배 정도 증가한 수치이다. 하지만 세균 다양성은 단순해져서 보다 적은 수의 세균이 분리, 동정되었다. Pseudomonas spp.가 대부분을 차지하였으며(~48%), Arthrobacter sp., Bacillus sp.가 그 뒤를 이었다. 동정된 세균 각각의 부패능을 검정하고자 무균배양한 상추에 접종하였으며, 그 결과 Pseudomonas fluorescence와 Pantoea agglomerans가 상당한 부패를 야기하였다.

• The Plant Pathology Journal
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• 제31권2호
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• pp.152-164
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• 2015

Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and $YC7010^T$, with antimicrobial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension ($10^7cfu/ml$) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC $15859^T$ (99.67%), Bacillus methylotrophicus KACC $13105^T$ (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC $17177^T$ (99.60%), and Bacillus tequilensis KACC $15944^T$ (99.45%). The DNA-DNA relatedness value between strain $YC7010^T$ and the most closely related strain, B. siamensis KACC $15859^T$ was $50.4{\pm}3.5%$, but it was $91.5{\pm}11.0%$ between two strains YC7007 and $YC7010^T$, indicating the same species. The major fatty acids of two strains were anteiso-$C_{15:0}$ and iso $C_{15:0}$. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC7007 and $YC7010^T$ represent novel species of the genus Bacillus, for which the name Bacillus oryzicola sp. nov. is proposed. The type strain is $YC7010^T$ (= KACC $18228^T$). Taken together, our findings suggest that novel endophytic Bacillus strains can be used for the biological control of rice diseases.

• 농약과학회지
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• 제15권4호
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• pp.495-501
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• 2011

한라산에서 해발 1000미터부터 100미터의 고도 간격으로 산림토양 샘플을 채집하고 총 398점의 토양 세균을 분리하여 항균 및 단백질 분해활성과 Auxin 생산특성을 규명하였다. 항균활성 균주를 선발하기 위해 주요 작물병원균 8종에 대하여 대치배양한 결과 여러 종의 병원균에 대해 항균활성을 가지는 26균주를 1차적으로 선발하였으며, 단백질 분해활성이 높은 34균주, Auxin을 생산하는 26균주도 함께 선발하였다. 토마토잿빛곰팡이병에 대한 생물검정 결과 Je28-4(Rhodococcus sp.)가 80%의 방제효과를 나타내었다. 한라산에서 분리한 항균 및 단백질 분해활성, Auxin 생산균주 중 대표적인 균주를 선발하여 종을 동정한 결과 다양한 속에 속하는 미생물이 동정되었으며 Bacillus 속이 12균주로 가장 많았고 Streptomyces 8균주, Paenibacillus 속 5균주, Chryseobacterium 속 5균주, Pseudomonas 속 4균주, Rahnella 속 2균주, Lysinibacillus 속 2균주, Burkholderia 속 2균주로 동정되었으며, Enterobacter, Janthinobacterium, Microbacterium, Rhodococcus, Sphingomonas 속은 각각 1균주씩 동정되었다. 본 실험 결과 선발된 균주들은 추후 다각도의 in vitro 검정 및 생물검정을 걸쳐 식물 생장촉진 및 병 방제용 다기능성 미생물 자재의 소재로 활용 가능성을 검토할 필요가 있다고 사료된다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2016년도 춘계학술대회 및 임시총회
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• pp.25-25
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• 2016

Biological control has many advantages as a disease control method, particularly when compared with pesticides. One of the most important benefits is that biological control is an environmental friendly method and does not introduce pollutants into the environment. Another great advantage of this method is its selectivity. Selectivity is the important factor regarding the balance of agricultural ecosystems because a great damage to non target species can lead to the restriction of natural enemies' populations. The objective of this research was to evaluate the effects of several different bacterial isolates on the efficacy of biological control of soil borne diseases. White rot caused by Sclerotium cepivorum was reported to be severe disease of garlic and chive. The antifungal bacteria Burkholderia pyrrocinia CAB08106-4 was tested in field bioassays for its ability to suppress white rot disease. In field tests, B. pyrrocinia CAB08106-4 isolates suppressed white rot in garlic and chive, with the average control efficacies of 69.6% and 58.9%, respectively. In addition, when a culture filtrate of B. pyrrocinia CAB08106-4 was sprayed onto wounded garlic bulbs after inoculation with a Penicillium hirstum spore suspension in a cold storage room ($-2^{\circ}C$), blue mold disease on garlic bulbs was suppressed, with a control efficacy of 79.2%. These results suggested that B. pyrrocinia CAB08106-4 isolates could be used as effective biological control agents against both soil-borne and post-harvest diseases of Liliaceae. Chinese cabbage clubroot caused by Plasmodiophora brassicae was found to be highly virulent in Chinese cabbage, turnips, and cabbage. In this study, the endophytic bacterium Flavobacterium hercynium EPB-C313, which was isolated from Chinese cabbage tissues, was investigated for its antimicrobial activity by inactivating resting spores and its control effects on clubroot disease using bioassays. The bacterial cells, culture solutions, and culture filtrates of F. hercynium EPB-C313 inactivated the resting spores of P. brassicae, with the control efficacies of 90.4%, 36.8%, and 26.0%, respectively. Complex treatments greatly enhanced the control efficacy by 63.7% in a field of 50% diseased plants by incorporating pellets containing organic matter and F. hercynium EPB-C313 in soil, drenching seedlings with a culture solution of F. hercynium EPB-C313, and drenching soil for 10 days after planting. Soft rot caused by Pectobacterium carotovorum subsp. carotovorum was reported to be severe disease to Chinese cabbage in spring seasons. The antifungal bacterium, Bacillus sp. CAB12243-2 suppresses the soft rot disease on Chinese cabbage with 73.0% control efficacy in greenhouse assay. This isolate will increase the utilization of rhizobacteria species as biocontrol agents against soft rot disease of vegetable crops. Sclerotinia rot caused by Sclerotinia sclerotiorum has been reported on lettuce during winter. An antifungal isolate of Pseudomonas corrugata CAB07024-3 was tested in field bioassays for its ability to suppress scleritinia rot. This antagonistic microorganism showed four-year average effects of 63.1% of the control in the same field. Furthermore, P. corrugata CAB07024-3 has a wide antifungal spectrum against plant pathogens, including Sclerotinia sclerotiorum, Sclerotium cepivorum, Botrytis cinerea, Colletotrichum gloeosporioides, Phytophotra capsici, and Pythium myriotylum.