• The Korean Journal of Mycology
• /
• v.38 no.2
• /
• pp.112-119
• /
• 2010

Pleurotus spp. have been used for edible and medicinal purposes in Asian countries for a long time. The fruiting bodies of the Pleurotus ostreatus, Pleurotus citrinopileatus and Pleurotus salmoneostramineus contained many physiologically beneficial substances for human health. Therefore, it is necessary to study the genetic diversity of Pleurotus mushroom cultivars commercially cultivated in Korea. Eleven strains of Pleurotus spp. were collected from different geographical regions in South-East Asia and ITS regions of rDNA and RAPD of genomic DNA were analyzed. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 167 to 254 bp and 156 to 213 bp, respectively. The sequence of ITS1 was more variable than that of ITS2, and the 5.8S sequences were identical. A phylogenetic tree based on the ITS region sequences indicated that selected strains could be classified into 4 clusters. Eleven Pleurotus species were also analyzed by RAPD with 20 arbitrary primers. Ten of these primers were efficiently amplified the genomic DNA. The number of amplified bands varied with the primers and strains, with polymorphic fragments in the range from 0.1 to 2.0kb. The results revealed that genetic diversity of selected strains of P. ostreatus, P. citrinopileatus and P. salmoneostramineus is low.

• Horticultural Science & Technology
• /
• v.34 no.2
• /
• pp.305-313
• /
• 2016

Brassica juncea (2n = 4x = 36, AABB genome, 1,068 Mb) is a U's triangle species and an amphidiploid derivative of B. rapa and B. nigra. Fifteen varieties were used to study the ITS (internal transcribed spacer) regions of ribosomal DNA and MITEs (miniature inverted-repeat transposable elements) with a view of developing specific molecular markers. ITSs and MITEs are an excellent resource for developing DNA markers for genomics and evolutionary studies because most of them are stably inherited and present in high copy numbers. The ITS (ITS1 and ITS2) sequence was compared with the consensus sequence of B. rapa and B. nigra. Variation in ITS1 created two separate groups among 15 varieties, with 10 varieties in one group and 5 in the other. Phylogenetic analysis revealed two major clusters for those 10 and 5 varieties. Among the 160 different MITE primers used to evaluate the selected 15 varieties of B. juncea, 70 were related to the Stowaway, 79 to the Tourist, 6 to the hAT, and 5 to the Mutator super-families of MITEs. Of 160 markers examined, 32 were found to be polymorphic when fifteen different varieties of B. juncea were evaluated. The variety 'Blackgat' was different from the other mustard varieties with respect to both phenotype and genotype. The diversity of 47 additional accessions could be verified using eight selected molecular markers derived from MITE family sequences. The polymorphic markers identified in this study can be used for varietal classification, variety protection, and other breeding purposes.

• Journal of Microbiology
• /
• v.45 no.2
• /
• pp.113-121
• /
• 2007

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

• Korean Journal of Plant Taxonomy
• /
• v.43 no.1
• /
• pp.63-68
• /
• 2013

ITS DNA sequences of two variants of Pinus spp. having single fasciculate leaf or two to three fasciculate leaves within an individual were analysed in order to determine their origin. Also, the same DNA locus of P. densiflora, P. rigida and P. koraiensis, distributed at the same region together with the OTUs having leaf variations, were analysed to compare with each other. Aligned sequences including ITS1, 5.8S and ITS2 were 580~584 bp in length. The 5.8S region was well conserved among all the OTUs we tested except for P. koraiensis, which has two nucleotide substitutions. The partial ITS1 region upstream of the 5.8S region showed relatively high sequence diversity compare to the ITS2 and has 181~185 bp in length. In this region, the sequences of the two variants were identical to that of P. densiflora. The ITS2 has identical for all OTUs in length and the two variants also have same sequences compare to that of P. densiflora. These two variants and samples of P. densiflora were grouped together in the UPGMA tree with 100% similarity level. The result strongly suggest that these two variants were originated from P. densiflora.

• Korean Journal of Environmental Biology
• /
• v.29 no.3
• /
• pp.144-153
• /
• 2011

In this study, samples were collected from the Sumummulbangdui wetland at the Halla Mountain in Jeju Island in order to isolate novel bacterial strain. Bacterial strains belonging to the class Alphaproteobacteria, and Gammaproteobacteria were isolated after spreading samples onto solid agar media. The 16S rRNA gene sequences of the strains assigned to the two classes were compared to those of type strains of the species. The strains that showed less than 98.7% 16S rRNA gene sequence similarity to the validly published species were considered to be novel species candidates. A total of 19 strains were regarded as novel strains which can be regarded as novel species candidates. In the Alphaproteobacteria, 6 novel strains were affiliated with the genera Novosphingobium, and Rhizobium. A total of 13 novel strains belong to Gammaproteobacteria that assigned to the family Moraxellaceae, Pseudomonadaceae, and Enterobacteriaceae were identified. Cultural, physiological, chemotaxonomic characteristics and fatty acids compositions have been determined for the novel species candidates, and the characteristics are described in this study.

• Korean Journal of Food Science and Technology
• /
• v.47 no.1
• /
• pp.126-131
• /
• 2015

Pathogenic Escherichia coli is recognized as an important cause of diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome worldwide. This study was conducted to investigate the prevalence E. coli contamination in the Korean traditional food bibimbap. E. coli were isolated from 84 of 1142 (7.3%) bibimbap investigated from 2005 to 2011. Antibiotic resistance profiling demonstrated that 6 of the 84 isolates (7.2%) showed multiple drug resistance. Fifteen virulence genes specific for pathogenic E. coli such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC) were examined by multiplex PCR for mixed bacterial cultures derived from bibimbap samples. The EPEC virulence gene (ent) was detected in 5 strains (5.9%), while ETEC, EAEC, and EIEC were not detected. STEC serotypes O103 (1.2%), O91 (1.2%), and O128 (6.0%) were found, but other serogroups such as O26, O157, O145, O111 and O121 were not detecded. Automated Repetitive-Sequence-Based PCR analysis showed different patterns.

• Animal Systematics, Evolution and Diversity
• /
• v.28 no.2
• /
• pp.133-136
• /
• 2012

The objective of this study was to determine the degree of mitochondrial DNA (mtDNA) divergence between two subspecies of $Mustela$ $sibirica$ from Korea ($M.$ $s.$ $coreanus$ on the Korean Peninsula and ($M.$ $s.$ $quelpartis$ on Jeju Island) and to examine the taxonomic status of ($M.$ $s.$ $quelpartis$. Thus, we obtained complete sequences of mtDNA cytochrome $b$ gene (1,140 bp) from the two subspecies, and these sequences were compared to a corresponding haplotype of ($M.$ $s.$ $coreanus$, downloaded from GenBank. From this analysis, it was observed that the sequences from monogenic ($M.$ $s.$ $quelpartis$ on Jeju Island were identical to the sequences of four ($M.$ $s.$ $coreanus$from four locations across the Korean Peninsula, and that the two subspecies formed a single clade; the average nucleotide distance between the two subspecies was 0.26% (range, 0.00 to 0.53%). We found that the subspecies $quelpartis$ is not genetically distinct from the subspecies $coreanus$, and that this cytochrome $b$ sequencing result does not support the current classification, distinguishing these two subspecies by pelage color. Further systematic analyses using morphometric characters and other DNA markers are necessary to confirm the taxonomic status of ($M.$ $s.$ $quelpartis$.

• Journal of Species Research
• /
• v.6 no.2
• /
• pp.101-118
• /
• 2017

In an investigation of indigenous prokaryotic species in Korea, a total of 57 bacterial strains assigned to the classes Betaproteobacteria and Gammaproteobacteria were isolated from diverse environments. Samples were collected from fresh water, natural caves, soil, paddy fields, lakes, sea water, jeotgal (fermented seafood), salt flats, soil from abandoned mines, plant roots, digestive organs of both Japanese crested ibis (Nipponia nippon) and Burmese python (Python molurus bivittatus) and tidal flats. From the high 16S rRNA gene sequence similarity (>98.7%) and formation of robust phylogenetic clades with closely related species, it was determined that each strain belonged to an independent and predefined bacterial species within either the Betaproteobacteria or Gammaproteobacteria. There is no official report or publication that describes these 57 proteobacterial species in Korea. Overall, in the class Betaproteobacteria there were 16 species in 12 genera of 4 families in the order Burkholderiales and two species in two genera of one family in the order Neisseriales. Within the class Gammaproteobacteia, there were five species in four genera of four families in the order Alteromonadales, 12 species in 11 genera of one family in the order Enterobacteriales, four species in four genera of three families in the order Oceanospirillales, 11 species in four genera of two families in the order Pseudomonadales, two species in the order Vibrionales and five species in five genera of one family in the order Xanthomonadales. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source and strain IDs are described in the species description section.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.12A
• /
• pp.1319-1332
• /
• 2004

Multicarrier direct sequence code-division multiple access CDMA(MC DS-CDMA) is an attractive technique for achieving high data rate transmission even if the potentially large peak-to-average power ratio(PAPR) is an important factor for its application. On the other hand, code select CDMA(CS-CDMA) is an attractive technique with constant amplitude transmission of multicode signal irregardless of subchannels by introducing code selection method. In this paper we propose a new multiple access scheme based on the combination of MC DS-CDMA and CS-CDMA. Proposed scheme, which we called MC CS-CDMA, includes the sutclasses of MC DS-CDMA and CS-CDMA as special cases. The performance of this system is investigated for multipath Sequency selective fading channel and maximal ratio combining with rake receiver. In addition the PAPR of proposed system is compare with that of both MC BS-CDMA and CS-CDMA. Simulation results show that proposed system improves PAPR reduction than MC DS-CDMA at the expense of the complexity of receiver and the number of available non. Also, the numerical result shows that the proposed system is better performance than MC DS-CDMA due to the increasing processing gain and the number of time diversity gain.

• Korean Journal of Childcare and Education
• /
• v.8 no.1
• /
• pp.45-64
• /
• 2012

This research is about how infants' multi-cultural recognition and their sphere of activity can be changed when married immigrant women and infants' homeroom teachers were put together in the infants' multi-cultural teaching program. The subjects(children under 5) were selected in "S" city of Gyeonggi-do, South Korea. And they were divided into experimental group 1, experimental group 2, and the control group. And this research did a pretest and post-test for the 60 children. The result of this research can be summarized into three parts. Therefore, it is possible to suggest that the improvement of infants' diversity recognition is affected by a certain kind of teacher and that he/ she can improve the infants' play ability. Experimental group 1 is proceeded by both married immigrant woman and the infants's homeroom teacher. Experimental group 2 was managed by only the homeroom teacher who was going through the same program as the teachers above. The control group was managed by a general nurturing program. This research did do a pretest and post-test for this experiment. -by Chun-Ok. Lee was used for infant's multi-cultural measurement. Mee-sook. Kim's measurement was used for measurement of playfulness between same age children. Meaningful differences was exposed in experimental group 1, experimental group 2, and the control group in sequence. The two experimental groups who had experienced a multi-cultural program seemed to have higher playfulness.