• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.855-868
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• 2014

Synthetic agro-chemicals have been widely used to control diseases on paprika but these days negative attention has been increasing to use of them because of several adverse effects. This research was conducted to isolate and to characterize the antagonistic microorganism to control major paprika diseases, gray mold rot, fruit and stem rot, phytophthora blight, sclerotium rot, and wilt disease. Analysis of the fatty acid and analysis of the 16S rDNA gene sequence revealed that YKJ1 isolated in this research belongs to a group of Serratia marcescens. Specially, 16S rDNA gene sequence of YKJ1 showed 99% of sequence similarity with S. marcescens. Observation through the optical microscope revealed that YKJ1 suppressed the spore germination and the hyphal growth of pathogens. YKJ1 treatment on pathogens induced marked morphological changes like hyphal swelling and degradation of cell wall. In the case of phytophthora blight, the zoosporangium formation was restrained. S. marcescens found in this study call as S. marcescens-YKJ1 and it may be valuable as one of biological control agents against major diseases of paprika in the future even though it is require to be tested with more study on field test.

• Mycobiology
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• v.28 no.1
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• pp.11-16
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• 2000

The nucleotide sequences of the internal transcribed spacer (ITS) regions of the ribosomal DNA including the 5.8S ribosomal RNA gene (rDNA) have been determined for 11 species in order to analyze their intrageneric relationships. The total length of these sequences ranged from 530 nucleotides for Trichoderma reesei KCTC 1286 to 553 nucleotide for Trichoderma koningii IAM 12534. Generally speaking, the length of ITS1 region was about 30 nucleotides longer than that of the ITS2 region. Also, 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 were also found. Thus, a neighbor-joining tree was constructed using the full sequence data of the ITS regions and the 5.8S rDNA. The Trichoderma genus used to be grouped on the basis of the morphological features and especially the shape of phialides needs to be reexamined. The phylogenetic tree displayed the presence of monophylogeny in the species of Trichoderma. Therefore, it was difficult to distinguish the intrageneric relationships in the Trichoderma genus.

• Parasites, Hosts and Diseases
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• v.34 no.2
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• pp.127-134
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• 1996

Twelve isolates of Accnthamoebc app. assigned to either A. castellanii or A. poIMphoSa, and type strains of A. culbefsoni, A. henIWi, A. pqkestinefiE, and A. astronyxi,s were examined by restriction fragment length polymorphism (RFLP) of a conserved region of small subunit ribosomal RMh gene (ssu rDNA) amplified by polymerase chain reaction (PCR). The PCR products of the isolates measured approximately 910-930 bp, except for that of A. astronyxis which was extraordinarily long, approximately 1,170 bp. Average of estimated sequence divergence of the amplified DNA among the isolates assigned to A. castellanii was 9.8% whereas that among the isolates assigned to A. polvphusn 9.6%. The maximum intraspecific sequence divergence among the isolates assigned to A. costellanii was observed between the Chang and Ma strains (17.3%) while that among the isolates assigned to A. poIWphosa was observed between KA/S3 and KA/S7 strains (16.1%). The both maximum sequence divergences were much greater than the minimum interspecific sequence divergence between A. cnstellnnii and A. polwphasa (2.6%) which appeared between the Castellani (or CCAP 1501/12 g) and KA/S3 strains. The PCR-RFLP patterns of A. culbertsoni, A. healyi, A. palestinensis, and A. ostronvxis were quite diverse from one another and from those of isolates assigned to either A. castellanii or A. polyphoga. It is suggested that taxonomic validity of the isolates assigned to either A. castellnnii or A. polyphoga should be reevaluated.

• International Journal of Oral Biology
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• v.42 no.3
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• pp.143-147
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• 2017

In a previous study, Peptoniphilus mikwangii was isolated from the human oral cavity as a new species. The purpose of this study was to develop P. mikwangii-specific PCR primers. The PCR primers were designed, based on the nucleotide sequence of 16S ribosomal RNA (16S rDNA). The specificity of the primers was tested using genomic DNAs of 3 strains of P. mikwangii and 27 strains (27 species) of non-P. mikwangii bacteria. The sensitivity of primers sensitivity was determined using PCR, with serial dilutions of the purified genomic DNAs (4 ng to 4 fg) of P. mikwangii KCOM $1628^T$. The data showed that P. mikwangii-specific qPCR primers (B134-F11/B134-R1 & B134-F5/B134-R5) could detect only P. mikwangii strains, and 400 fg or 40 fg of P. mikwangii genome DNA. These results suggest that PCR primers are useful in detecting P. mikwangii from the oral cavity.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.68-78
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• 2006

The purpose of this study was to estimate the identification of thermophilic hacterial with fermentation of pig manure. To identify the characters of thermophilic bacteria related to fermentation at a high temperature condition, we selected 28 different kinds of original settling thermophilic bacteria that were sampled at different 23 areas. They were distributed 1$1{\times}10^5{\sim}10^8CFU$ at medium and the enzyme activity at $55^{\circ}C$ incubation condition, especially cellulase and a-amylase, were higher than those of $30^{\circ}C$. Partial sequencing data for 165 rDNA region were obtained from 28 samples representing 15 different genera. Bacillus subcilis, one of those bacteria, has endodermic spores at high fermented condition.

• Food Science and Preservation
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• v.17 no.3
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• pp.410-417
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• 2010

Several extracellular protease-producing bacteria were isolated from Chungkookjang, a traditional Korean food of fermented soybeans, on skim milk agar plates. Among these bacteria, strain D14 exhibited the highest production (15.2 U/mL) and specific activity (40.0 U/mg protein) of extracellular protease activity as assessed on growth in a protease induction medium composed of 1% (w/v) soluble starch, 1.5% (w/v) skim milk, 0.5% (w/v) yeast extract, and 2% (w/v) NaCl. The bacterium was identified as Bacillus subtilis based on morphological and physiological characteristics and 16S rDNA sequence. A BLAST search of 16S rDNA sequences revealed that the isolate was most closely related to Bacillus subtilis subsp. subtilis strain NCIB 3610. The 16S rDNA sequence homology was 99.9%. Our isolate produced the highest level of protease when grown in a protease induction medium containing 1% (w/v) sorbitol and 0.5% (w/v) yeast extract. Fructose and glucose reduced enzyme production to 12.7% and 35.9%, respectively, of the level seen when the strain was grown in medium containing soluble starch. Soytone also reduced enzyme production to 61.4% of the level noted when the strain was grown in medium containing yeast extract.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.133-148
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• 2015

Although several adverse effects have been increased in recent years, synthetic agro-chemicals have been widely used to control diseases on paprika. This research was conducted to isolate and to characterize the antagonistic microorganism to control major paprika diseases, gray mold rot, fruit and stem rot, phytophthora blight, sclerotium rot, and wilt disease. Analysis of the fatty acid and analysis of the 16S rDNA gene sequence revealed that YKJ2 isolated in this research belongs to a group of Burkholderia cepacia. Specially, 16S rDNA gene sequence of YKJ2 showed 99% of sequence similarity with B. cepacia. Observation through the optical microscope revealed that YKJ2 was effective on suppression of the spore germination and the hyphal growth of pathogens. YKJ2 treatment on pathogens induced marked morphological changes like hyphal swelling and degradation of cell wall. In the case of phytophthora blight, the zoosporangium formation was restrained. On the basis of the results of this study, we propose that an antagonistic microorganism, B. cepacia, found in this study naming as "B. cepacia strain YKJ2" and has great potential as one of biological control agents against major diseases of paprika.

• Research in Plant Disease
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• v.10 no.1
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• pp.63-68
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• 2004

Twenty-three strains of Serratia sp., isolated from surface-sterilized rice roots collected in Chonbuk and Chungnam province, were identified and characterized. They were Gram-negative, rod shaped and red pigmented typically and their endophytism was confirmed by inoculation and reisolation of the strains in planta. Their antifungal activity against 4 rice pathogenic fungi was compared and ranged from 62.4 to 85.2％ against Rhizoctonia solani and 68.0 to 88.5％ against Pyricularia grisea. Among the 23 strains tested, strain Rsm220 showed the strongest inhibition activity against 4 pathogenic fungi. The strain was, therefore, selected as a biocontrol candidate for both the pathogens and its bacteriological characteristics and 165 rDNA sequences were analyzed. Phenotypic and biochemical characteristics of the selected Rsm220 were highly related to the type strain of S. marcescens and 165 rDNA sequencing of Rsm220 showed a homology of 98.2％ to the type strain of S. marcescens. The strain Rsm220 was identified as S. marcescens and the inhibition result of this endophytic strain indicates that it is a potential biocontrol agent for R. solani and R grisea.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.66-74
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• 2004

In order to clarify intra-and inter-specific variation of Korean Rana species, the partial DNA sequences of mitochondrial 16S rDNA gene were determined from 6 Korean and 1 Japanese Rana species, DNA sequences from Korean and Japanese species were comparison-analysed within, and also with the sequences from three species of Japanese brown frogs. DNA similarities were calculated as 91.3∼97.3％ among brown frog (R. amurensis coreana, R. dybowskii and R. huanrenensis), as 96.11∼97.26％ among pond frogs (R. nigromaculata and R. planeyi chosenica). Genetic distance of pond frog and wrinkle fyog (R. rugosa) were near than that of pond frog and brown frog. Two clusters were formed brown frogs and the other group by neigh-bor-joining and maximum-likelihood analysis, also the populations of R. nigromaculata were well distinguished between Korean peninsula and Korean island. But result from maximum-likelihood analysis slightly differed from neighbor-joining to cluster of R. rugosa. Further analyses for their population will be necessary to study the phylogenetic status.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1882-1889
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• 2006

A 16S rDNA clone library was generated to investigate the bacterial diversity in intertidal sediment from the coast of the Yellow Sea, P. R. China. A total of 102 clones were sequenced and grouped into 73 OTUs using a phylogenetic approach. The sequenced clones fell into 11 bacterial lineages: Proteobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Acidobacteria, Actinobacteria, Firmicutes, Spirochaetes, and candidate divisions of BRCl, OP3, and OP1l. Based on a phylogenetic analysis of these bacteria, together with the ten most closely related sequences deposited in the GenBank, it was concluded that intertidal bacteria are most likely derived from marine bacteria with a remarkable diversity, and some are particularly abundant in intertidal sediment.