• Korean Journal of Weed Science
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• v.8 no.1
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• pp.9-14
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• 1988

Three varieties of Echinochloa crus-galli (L.) Beauv. and five collections different in gross morphology from the E. crus-galli species were obtained in a lowland rice field located in Jukjeol-Ri, Soyang-Myeon, Wanju-Kun, Jeonbug to compare the ecological and physiological characteristics. There were great variations in seed dormancy, relative growth rates, days required to panicle emergence and panicle morphology among the collections. On the basis of the cluster analysis using the different characteristics, the collections were divided into three groups; E. crus-galli var. frumentaceae and its two ecotypcs, E. crus-galli var. echinata and its two ecotypes, and E crus-galli var. crus-galli and its one ecotype. There were differential responses in percent germination and post-germination growth of the collections to butachlor (2-chloro-2', 6'-diethyl-N-butoxymethyl acetanilide).

• Journal of Life Science
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• v.22 no.3
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• pp.285-292
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• 2012

Genus Spiraea is composed of many long-lived woody species that are primarily distributed throughout Asia and Europe. In this study, we evaluated a representative sample of the 38 taxa in the world, including 14 in Korea, with nuclear ribosomal DNA internal transcribed spacer sequences (ITS) to estimate genetic relationships within the genus. The molecular data allowed us to resolve well-supported clades in the taxa. In 47 world accessions (38 taxa: 14 Korean taxa, 33 world taxa, and 9 overlapping taxa), total alignment length was 689 positions, of which 452 were parsimony informative, 527 variable, 75 singleton, and 159 constant characters. Although the phylogenic tree showed that many taxa of genus Spiraea were well separated from each other, many branches were not congruent with the morphological characteristics and geographical distributions of the genus. There were 430 segregating sites and the nucleotide diversity (${\pi}$) value was 0.281. Under the neutral mutation hypothesis, the probability that the Tajima test statistic (D) is positive (2.325) is more than 0.5. Therefore, there may be a site at which natural selection, which increases genetic variation, is operating.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.293-302
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• 2010

Taxa of Artemisia collected in Korea were constructed by molecular phylogenetic analysis based on the internal transcribed spacer(ITS) regions of nrDNA. The length of the ITS sequences aligned using the clustal X program was 636~643 bp, and the lengths of the ITS1 and ITS2 regions were 251~255 bp and 217~222 bp, respectively. The total number of variable sites was 95 for the entire sequence, and a parsimony- informative site represented an efficacious site in ITS1 rather than in ITS2. The maximum parsimony tree as calculated by the MEGA 4 program was clustered into five clades. The taxa(A. capillaris, A. japonica var. japonica, A. japonica var. hallaisanensis, A. japonica subsp. littoricora) degenerated ovary of clade 1 was supported as the subgenus Dracunculus by Ling's classification system. The results show that A. nakaii and A. fukudo were quite similar genetically(Boostrap 99%) and that the scientific name of Korean A. dubia should be reconsidered. A. sp. distributed in Ganghwa province was grouped with A. argyi(Boostrap 89%). These results suggest that the molecular techniques used in this study could be useful for the phylogenetic analysis of Korean Artemisia herbs having variations in their morphological characteristics.

• Korean Journal of Plant Taxonomy
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• v.37 no.2
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• pp.115-129
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• 2007

Using internal transcribed spacer (ITS) sequences and inter-simple sequence repeats (ISSRs) data, genetic diversity of a rare species, Hibiscus hamabo Siebold & Zucc. was examined for 3 populations in Jeju Island, Korea. A total of 14 nucleotide (excluding 3 ambiguous nucleotide) site variation in the ITS was observed from 18 individuals (Population 1, Hadori), which differed up to 13 bp in pair-wise comparison. On the contrary, the ITS sequences of all individuals in Populations 2 and 3 were identical. Genetic diversity estimates including Nei's gene diversity (h) generated by ISSR data were substantially high in Population 1 compared to other two populations. Low genetic variation in Populations 1 and 2 is considered due to genetic drift (bottleneck effect) and limited gene flow in these populations. Considering the differences in genetic diversity, protection of the Population 1(Hadori) is very critical for in situ conservation of Hibiscus hamabo in Korea. If ex situ conservation is required, making the full use of Population 1 will be most efficient.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.162-170
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• 2012

The objectives of this study were to isolate and the sequence of novel $F3'H$ gene related to an anthocyanin pathway, and to confirm the expression patterns of the gene involved in the flower color variations of chrysanthemum mutants. In this study, we isolated the full-length cDNAs and the genomic DNAs of an $F3'H$ gene from a wild type (WT) chrysanthemum (cv. Argus) and its three color mutants. The sequence analysis revealed a putative open reading frame of 1,527 bp that encodes a polypeptide of 509 amino acids. Sequence homology ranged from 97% to 99% between 'Argus' and its three color mutants. The sequence analysis from the genomic DNA revealed that the chrysanthemum $DgF3'H$ gene consisted of three exons and two introns spanning a 3,830 bp length. The sizes of the gene for three mutants ranged from a shorter size of 3,828 bp to a longer size of 3,838 bp when compared to the size of WT. The total size of the two introns was 2,157 bp for WT, but those for three color mutants ranged from 2,154 bp to 2,159 bp. A result of an RT-PCR analysis indicated that the color variations of the mutants AM1 and AM2 can be partly explained by the structural modification derived from the sequencial changes in the gene caused by gamma ray. A Southern blot analysis revealed that the $DgF3'H$ gene existing as multiple copies in the chrysanthemum genome. A systemic study will be further needed to provide a genetic mechanism responsible for the color mutation and to uncover any involvement of genetic elements for the expression of the $DgF3'H$ gene for the color variation in chrysanthemum.

• Korean Journal of Food Science and Technology
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• v.14 no.1
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• pp.72-79
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• 1982

Several mutants were isolated from the parent strain of Aspergillus niger CF: the first mutant strain CF-11 was obtained by UV irradiation, and the second mutant strain CF-21 and CF-22 were from NTG (N-methyl-N'-nitroso-N-nitroso-guanidine) treatment on the CF-11. These mutants were characterized, and their enzyme and acid production on wheat bran Koji and wheat flour Koji were studied. Asp. niger CF-22 mutant appeared to be tan type which conidial heads were discolored. It's glucoamylase activity was inreased approximately two times and its ${\alpha}-amylase$ about 50 percent as compared with that of the parent strain of Asp. niger CF, when grown on wheat bran Koji under the optimal conditions. Asp. niger CF-21 mutant showed slower growth rate and poor sporulation than the wild type, although its conidial heads were not discolored. Approximately 4-fold increment in its acid production was observed as compared with the weld type. The activities of glucoamylase and ${\alpha}-amylase$ of the Asp. niger CF-22 and CF-21 mutants were higher than those of the wild type, but their protease activity was rather lower. The maximum production of glucoamylase by the Asp. niger CF-22 mutant was obtained after 2 to 3 days incubation on wheat bran at 30 to $35^{\circ}C;$ ${\alpha}-amylase$2 days incubation at 30 to $35^{\circ}C$. The maximal levels of acid production by the mutant CF-21 was appeared after 2 days incubation on wheat bran Koji, and after 3 days on wheat flour Koji at $30^{\circ}C$. Little differences in the levels of acid production were observed between on wheat bran and flour Koji.

• Applied Biological Chemistry
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• v.41 no.1
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• pp.18-22
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• 1998

A mutant strain which hyperproduced thermostable ${\alpha}-amylase$ was obtained by chemical mutagenesis of Bacillus licheniformis. The mutant strain, SK-5, produced the enzyme about 50 times higher than the original strain. The mutant was longer and slimmer in shape, slower in growth compared to the original strain. Nucleotide sequence analysis of the SK-5 ${\alpha}-amylase$ gene revealed no changes in the the structural gene. The changes found in the promoter region might be responsible for the hyperproduction of the enzyme by the mutant. No structural changes in the enzyme structure could be observed when the secreted enzymes at various culture times were analyzed by Western blot.

• Food Science of Animal Resources
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• v.22 no.4
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• pp.352-357
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• 2002

Antimutagenic effects of extracts from curry powder and its individual fourteen kinds of spices, were investigated by Ames test. The antimutagenic effects against a direct mutagen, 2-nitrofluorene(2 -NF) and two indirect mutagens, 2-anthramine(2-AT) and 2-acetamidofluorene (2-AE) in the S. typhimurium TA98 were tested. For the 2-NF, the antimutagenicity of cinnamon, fenugreek, fennel, ginger, clove, turmeric and celery seed were determined as 42, 38, 32, 28, 24, 23 and 20%, respectively. The antimutagenicity of clove against the 2-AT was the highest (116%), and followed by the order of celery seed(103%), cardamon(100%), red pepper(99%), cinnamon(92%), cumin(83%), ginger(82%), fennel(82%), coriander (71%), nutmeg(68%) and turmeric (55%). The results also showed that the antimutagenic effect of clove against the 2-AF was superior to other spices. In case of curry powder among more than 10 kinds of spices, the antimutagenenicity against the 2-AT and 2-AF showed 23% and 6%, respectively, but no effect was observed against the 2-NF.

• Journal of Life Science
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• v.12 no.6
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• pp.821-834
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• 2002

In order to measure the inter- and intraspecific genetic divergences within the genus Alexandrium, the variations within the internal transcribed spacer (ITS1 and ITS2) regions and 5.85 ribosomal RNA gene of eight Alexandrium species were examined for 33 strains from diverse geographical locations by direct sequencing. Five isolates of A. tamarense (AT-2, AT-6, AT-10, AT-A and AT-B) from Jinhae Bay, Korea were found to be completely identical to a Japanese strain OFX151-A. The length of the amplified ITSI-5.85-ITS2 region varied from 481 nucleotides (in A. margalefi) to 528 nucleotides (in A. affine CU1-1). ITS1 and ITS2 nucleotide lengths were negatively correlated, whereas a positive correlation was found between their G＋C content. The degree of sequence divergence ranged from 0.3% (1 bp) to a maximum of 53% (305 Up). Pairwise sequence comparisons revealed a small degree of divergence between A. tamarense and A. Pundyense isolates (1.2 - 2.3% ＝ 6-12 bp), but a high degree of divergence between A. tamarense and A. catenella (19.8% ＝ 102 bp), and between A. catenella and A. Pundyense (19.7%). Although most nodes were weakly supported by bootstrap values, some types tend to form independent molecular groups. A. catenella isolates also formed an independent molecular sub-group, with relaticula strong bootstrap values (94% or 85% and 79% or 98%, respectively in PAUP and NJ trees). Interestingly, A. cohorticula and A. frateculus always clustered within the same sub-group, this result being supported by strong bootstrap values. Our results indicate that the ITS regions provide useful informations on hierarchical population genetic structure and a high phylogenetic resolution in intraspecific and interspecific Alexandrium population.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.3
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• pp.20-27
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• 2006

Power line for digital home appliances has own property that transmitting power connected to loads. Especially, power line communication(PLC) for the home network which has characteristics of load fluctuation makes variable noise characteristics. It becomes serious problems to maintain efficient communication performance. Thus, in this paper, we present an optimal modulation and demodulation method through mathematical analysis of each measured load fluctuation based on PLC for home appliances. To analyze and compare various modem methods presented in this paper, we analyzed them normally via computer simulation under various noise channel environments according to various load fluctuations. In addition, we certified its availability through hardware implementation.