• Journal of Species Research
• /
• v.5 no.2
• /
• pp.241-253
• /
• 2016

In 2014, as a subset study to discover indigenous prokaryotic species in Korea, a total of 33 bacterial strains assigned to the class Gammaproteobacteria were isolated from diverse environmental samples collected from soil, tidal flat, freshwater, seawater, oil-contaminated soil, and guts of animal. From the high 16S rRNA gene sequence similarity (>98.5%) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that these 33 species have been described in Korea; therefore, 1 strain of the Aeromonadales, 6 strains of the Alteromonadales, 3 strains of the Chromatiales, 5 strains of the Enterobacteriales, 4 strains of the Oceanospirillales, 11 strains of the Pseudomonadales, and 3 strains of the Xanthomonadales within the Gammaproteobacteria are described for unreported bacterial species in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, and isolation sources are also described in the species description section.

• Journal of Species Research
• /
• v.5 no.2
• /
• pp.206-219
• /
• 2016

As a subset study to discover indigenous prokaryotic species in Korea, a total of 42 bacterial strains assigned to the class Alphaproteobacteria were isolated from diverse environmental habitats including plant roots, ginseng soil, forest soil, marsh, mud flat, freshwater, and seawater. From the high 16S rRNA gene sequence similarity (>99.1%) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that these 42 species have been described in Korea; therefore 4 species of 1 genera in the order Caulobacterales, 18 species of 10 genera in the order Rhizobiales, 7 species of 5 genera in the order Sphingomonadales and 13 species of 11 genera in the order Rhodobacterales within the Alphaproteobacteria are reported for alphaproteobacterial species found in Korea. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are also described in the species description section.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.2
• /
• pp.111-120
• /
• 2017

This paper proposes an improved standard genetic algorithm (GA) of making a near optimal schedule for integrated process planning and scheduling problem (IPPS) considering tool flexibility and tool related constraints. Process planning involves the selection of operations and the allocation of resources. Scheduling, meanwhile, determines the sequence order in which operations are executed on each machine. Due to the high degree of complexity, traditionally, a sequential approach has been preferred, which determines process planning firstly and then performs scheduling independently based on the results. The two sub-problems, however, are complicatedly interrelated to each other, so the IPPS tend to solve the two problems simultaneously. Although many studies for IPPS have been conducted in the past, tool flexibility and capacity constraints are rarely considered. Various meta-heuristics, especially GA, have been applied for IPPS, but the performance is yet satisfactory. To improve solution quality against computation time in GA, we adopted three methods. First, we used a random circular queue during generation of an initial population. It can provide sufficient diversity of individuals at the beginning of GA. Second, we adopted an inferior selection to choose the parents for the crossover and mutation operations. It helps to maintain exploitation capability throughout the evolution process. Third, we employed a modification of the hybrid scheduling algorithm to decode the chromosome of the individual into a schedule, which can generate an active and non-delay schedule. The experimental results show that our proposed algorithm is superior to the current best evolutionary algorithms at most benchmark problems.

• Korean Journal of Medicinal Crop Science
• /
• v.19 no.3
• /
• pp.185-190
• /
• 2011

The principal objective of this study was to develop a discrimination method using SSR markers in Korean ginseng cultivars. Five cultivars--Chunpoong, Yunpoong, Gopoong, Sunpoong, and Kumpoong--were evaluated by nine markers out of 22 SSR markers. A total of 23 alleles were detected, ranging from 1 to 4, with an average of 2.6 alleles per locus, and an averages of gene diversity (GD) of 0.480. Nine markers were tested in order to distinguish among five Korean ginseng cultivars. Two markers out of nine SSR markers, GB-PG-065 and GB-PG-142, were selected as key markers for discrimination among Korean ginseng cultivars. Two genotypes were detected in GB-PG-065. Chunpoong and Kumpoong shared the same allele type, and Yunpoong, Gopoong, and Sunpoong shared another identical allele type. In the case of GB-PG-142, a specific allele type differentiated from those of other four cultivars was observed only in Sunpoong cultivar. Consequently, the SSR markers developed in this study may prove useful for the identification of Korean ginseng cultivars and the development of ginseng seed management systems, as well as tests to guarantee the purity of ginseng seeds.

• 한국균학회소식:학술대회논문집
• /
• 2014.10a
• /
• pp.49-49
• /
• 2014

In order to find indigenous beneficial fungal species from crop field soils of Nigeria, 23 soil samples were collected from various places of Nigeria in June, 2013 and fungi were isolated through serial dilution technique. Isolated fungi were purified and differentiated according to their morphological and microscopic characteristics. In total, 38 different representative isolates were recovered and the genomic DNA of each isolates was extracted using QIAGEN$^{(R)}$ Plasmid Mini Kit (QIAGEN Sciences, USA) and the identification of fungi was carried out by sequence analysis of internal transcribed spacer (ITS) region of the 18S ribosomal DNA (18S rDNA). Recovered isolates belonged to 9 fungal genera comprising Fusarium, Aspergillus, Chaetomium, Coniothyrium, Dipodascaceae, Myrothecium, Neosartorya, Penicillium and Trichoderma. Aspergillus spp., Penicillium spp. and Trichoderma spp. were the most dominant taxa in this study. The antagonistic potentiality of species belonged to Trichoderma against 10 phytopathogenic fungi (F. oxysporum, C. gloesporoides, P. cytrophthora, A. alternata, A. solani, S. rolfsii, F. solani, R. solani, S. sclerotiorum and P. nicotiana) was assessed in vitro using dual culture assay. The dual culture assay results showed varied degree of antagonism against the tested phytopathogens. The potential Trichoderma spp. will be further evaluated for their antagonistic and plant growth promotion potentiality under in vivo conditions.

• Korean Journal of Weed Science
• /
• v.18 no.1
• /
• pp.76-83
• /
• 1998

Echinochloa species maintained by selling for more than 10 years were classified using random amplified polymorphic DNAs(RAPDs) analysis. Seventy-four decamer of randomly sequence markers were used to classify intraspecific variation irt Echinochloa species. The number of amplification products increased with increasing GC content of the primer in the range between 60% and 70% GC. Single-base substitutions of a primer altered amplification, providing new polymorphisms. The size of amplified DNA was mostly between 0.40kbp and 1.4kbp with the most common bands at 1.1kbp. Echinochloa species were detected with 6 primers which generated 26 polymorphic amplified DNAs. By hierarchical cluster analysis, Echinochloa species collected in Korea were divided into three groups. These results revealed that RAPD markers are useful tools for the determination of genetic variations in Echinochloa species.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.3
• /
• pp.301-310
• /
• 2012

Prosopis juliflora and Parthenium hysterophorus are the two arid, exotic weeds of India that are characterized by distinct, profuse growth even in nutritionally poor soils and environmentally stressed conditions. Owing to the exceptional growth nature of these two plants, they are believed to harbor some novel bacterial communities with wide adaptability in their rhizosphere. Hence, in the present study, the bacterial communities associated with the rhizosphere of Prosopis and Parthenium were characterized by clonal 16S rRNA gene sequence analysis. The culturable microbial counts in the rhizosphere of these two plants were higher than bulk soils, possibly influenced by the root exudates of these two plants. The phylogenetic analysis of V1_V2 domains of the 16S rRNA gene indicated a wider range of bacterial communities present in the rhizosphere of these two plants than in bulk soils and the predominant genera included Acidobacteria, Gammaproteobacteria, and Bacteriodetes in the rhizosphere of Prosopis, and Acidobacteria, Betaproteobacteria, and Nitrospirae in the Parthenium rhizosphere. The diversity of bacterial communities was more pronounced in the Parthenium rhizosphere than in the Prosopis rhizosphere. This culture-independent bacterial analysis offered extensive possibilities of unraveling novel microbes in the rhizospheres of Prosopis and Parthenium with genes for diverse functions, which could be exploited for nutrient transformation and stress tolerance in cultivated crops.

• Journal of Ginseng Research
• /
• v.36 no.2
• /
• pp.211-217
• /
• 2012

Endophytic fungi were isolated from various tissues (root, stem, petiole, leaf, and flower stalk) of 3- and 4-year-old ginseng plants (Panax ginseng Meyer) cultivated in Korea. The isolated endophytic fungi were identified based on the sequence analysis of the internal transcribed spacer (ITS), 1-5.8-ITS 2. A morphological characterization was also conducted using microscopic observations. According to the identification, 127 fungal isolates were assigned to 27 taxa. The genera of Phoma, Alternaria and Colletotrichum were the most frequent isolates, followed by Fusarium, Entrophospora and Xylaria. Although 19 of the 27 taxa were identified at the species level, the remainder were classified at the genus level (6 isolates), phylum level (Ascomycota, 1 isolate), and unknown fungal species (1 isolate). Endophytic fungi of 13 and 19 species were isolated from 3- and 4-year-old ginseng plants, respectively, and Phoma radicina and Fusarium solani were the most frequently isolated species colonizing the tissues of the 3- and 4-year-old ginseng plants, respectively. The colonization frequency (CF%) was dependant on the age and tissue examined: the CFs of the roots and stems in the 3-year-old ginseng were higher than the CF of tissues in the 4-year-old plants. In contrast, higher CFs were observed in the leaves and petioles of 4-year-old plants, and endophytic fungi in the flower stalks were only detected in the 4-year-old plants. In conclusion, we detected diverse endophytic fungi in ginseng plants, which were distributed differently depending on the age and tissue examined.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.28 no.2
• /
• pp.39-50
• /
• 2014

In order to understand the diversity and genetic relationships of silkworm strains preserved in Korea, we genotyped 78 Bombyx mori strains (Bombycidae: Lepidoptera) originating from Japan, using eight polymorphic microsatellite loci. We obtained per-locus allele numbers ranging from 5 to 16 (with an average value of 9.1), per-locus observed heterozygosity ranging from 0.13 to 1.00, and per-locus polymorphic information content ranging from 0.36 to 0.77, indicating that some loci are highly variable. Phylogenetic analysis with the eight concatenated microsatellite loci showed no clustering based on known strain characteristics and origin. Nineteen strain-specific apomorphic alleles, which discriminated 16 of the 78 silkworm strains, were obtained from eight loci. These strain-specific alleles can thus be utilized for routine discrimination of strains from Japan, without any further typing of other loci. Homozygotes were also observed at some loci (27 of 118 genotypes), which can also be used to discriminate several strains by typing a few loci. These results showed that eight microsatellite loci described herein were sufficiently variable to discriminate among the 78 silkworm strains we examined, and may be useful for future investigations of this economically important species.

• Mycobiology
• /
• v.38 no.2
• /
• pp.89-96
• /
• 2010

This study evaluated the optimal vegetative growth conditions and molecular phylogenetic relationships of eleven strains of Agrocybe cylindracea collected from different ecological regions of Korea, China and Taiwan. The optimal temperature and pH for mycelial growth were observed at $25^{\circ}C$ and 6. Potato dextrose agar and Hennerberg were the favorable media for vegetative growth, whereas glucose tryptone was unfavorable. Dextrin, maltose, and fructose were the most effective carbon sources. The most suitable nitrogen sources were arginine and glycine, whereas methionine, alanine, histidine, and urea were least effective for the mycelial propagation of A. cylindracea. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR. The sequence of ITS2 was more variable than that of ITS1, while the 5.8S sequences were identical. The reciprocal homologies of the ITS sequences ranged from 98 to 100%. The strains were also analyzed by random amplification of polymorphic DNA (RAPD) using 20 arbitrary primers. Fifteen primers efficiently amplified the genomic DNA. The average number of polymorphic bands observed per primer was 3.8. The numbers of amplified bands varied based on the primers and strains, with polymorphic fragments ranging from 0.1 to 2.9 kb. The results of RAPD analysis were similar to the ITS region sequences. The results revealed that RAPD and ITS techniques were well suited for detecting the genetic diversity of all A. cylindracea strains tested.