• Development and Reproduction
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• v.24 no.3
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• pp.207-214
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• 2020

Primary cell culture is a sufficient method frequently used to study the cellular properties and mechanisms of isolated cells in a controlled environment. In this study, an embryonic cell line (FGBC8) derived from the blastula stages of embryos of olive flounder Paralichthys olivaceus was developed. Furthermore, conditions for optimal long-term maintenance of this primary embryonic cell culture were investigated. Morphologically, FGBC8 cells were composed primarily of epithelial-like cells. FGBC8 cells were subcultured for >160 passages over ~830 days. The doubling time of FGBC8 cells was 73.8 h, and the modal diploid chromosome number was 48. FGBC8 cells transfected with green fluorescence protein (GFP)-expression plasmid exhibited a strong signal 48 h after transfection. Consequently, we demonstrated that fish serum is a crucial supplement for the long-term survival and maintenance of comparable morphology in these primary embryonic cells. Our results can be used as a guide for primary embryonic cell cultures for other fish species and may be useful for cell biotechnological applications.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.35-39
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• 1995

In order to investigate the effects of gelling agent on rice anther culture, anthers of rice (Japonica cv Daecheongbyeo) were cultured on N$_{6}$ media supplemented with 0.8, 1.2 or 1.6% Junsei agar and 05, 0.4, 0.6, 0.8 or 1.0% Gelrite (Phytagel, Sigma). On Junsei agar media, the frequency of callus induction was decreased in proportion to agar concentration. The frequency of callus induction was more increased as 67.6% and 54.8% in media containing 0.4 and 0.6% Gelrite than in agar media. The frequency of plant regeneration and spontaneous doubled-diploid was directly proportional to Junsei agar and Gelrite concentration. The number of green and spontaneous doubled diploid plant was highest on 0.6% Gelrite medium. In order to optimize the concentration of growth regulators for the callus induction medium containing 0.6% Gelrite, anthers were cultured on N$_{6}$ media supplemented with 2mg/L NAA, 2 mg/L 2,4-D, 1mg/L NAA and 1mg/L 2, 4-D, or 1mg/L NAA, 1mg/L 2,4-D and 0.5mg/L kinetin. The maximum frequency of callus induction and plant regeneration was obtained from the medium supplemented with 2 mg/L NAA and 0.6% Gelrite. In conclusion the induction of embryogenic callus, the frequency of plant regeneration and in vivo chromosome doubling was more effective in Gelrite media than in Junsei agar media.dia.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.46-53
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• 2001

A commensal thermophile, Symbiobacterium toebii, isolated from hay compost (toebii) in Korea commensally interacted with a thermophilic Geobacillus toebii sp. nov., which was a new species within the genus Geobacillus on the basis of the phenotypic traits and molecular systematic data. S. toebii required the crude extracts and/or culture supernatant of the Geobacillus toebii for axenic growth and could grow on the temperature between 45 and $70^{\circ}C$ (optimum: $60^{\circ}C$; 2.4 h doubling time) and pH 6.0 and 9.0 (optimum: pH 7.5). The G+C content of the genomic DNA was $65 mol\%$, and the major quinones were MK-6 and MK-7. A phylogenetic analysis of its 16S rDNA sequence indicated that Symbiobacterium toebii was closely related with solely reported Symbiobacterium thermophilum. The presence of the commensal thermophile 16S rDNA and accumulation of indole in all the enriched cultures indicate that Symbiobacterium toebii is widely distributed in the various soils. The genome of S. toebii constituted a circular chromosome of 3,280,275 base pairs and there was not an extra-chromosomal element (ECE). It contained about 4,107 predicted coding sequences. Of these protein coding genes, about $45.6\%$ was encoded well-known proteins and annotated the functional assignment of 1,874 open reading frames (ORFs), and the rest predicted to have unknown functions. The genes encoding thermostable tyrosine phenol-lyase and tryptophan indole-lyase were cloned from the genomic DNA of S. toebii and the enzymatic production of L-tyrosine and L-tryptophan was carried out with two thermostable enzymes overexpressed in recombinant E. coli.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.291-296
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• 2012

Triploids are a useful tool for biomass production and molecular breeding of trees with a long life span. Triploids of the poplar 'Hyunsasi' (Populus alba ${\times}$ P. glandulosa) have been developed by crossing between female diploids and a male tetraploid. The tetraploid was developed around the 1970s at Korea Forest Research Institute by colchicine-induced chromosome doubling. Seedlings of the $F_1$ generation were analyzed using flow cytometry to verify their ploidy status. The mean relative fluorescence index of 3 F1 poplars, labeled as Line- 1, Line-17, Line-18, were approximately 1.5 times higher than those of diploid poplars, and the results clearly indicated that they were triploids. The phenotype of the F1 poplars included larger leaves and thicker stem than diploids, and abnormal leaf morphology, especially in the triploid 'Line-18'. Three triploid lines developed roots more slowly and had less roots than diploid. However, 3 poplar cytotypes (2x, Line-1, Line-17) rooted within 10 days on MS medium. In contrast, compared with the 3 cytotypes, the Line-18 showed about 80% and 70% in the rooting rate and the number of roots. The triploid poplars could be directly utilized for biomass production and with their sterility, they could serve as basic material for genetic transformation. In addition, flow cytometric analysis proved to be an effective and reliable method for screening forest trees for their ploidy level.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.12-20
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• 2016

Advances in DNA sequencing technologies have contributed to revolutionary understanding of many fundamental biological processes. With unprecedented cost-effective and high-throughput sequencing, a single laboratory can afford to de novo sequence the whole genome for species of interest. In addition, population genetic studies have been remarkably accelerated by numerous molecular markers identified from unbiased genome-wide sequences of population samples. As sequencing technologies have evolved very rapidly, acquiring appropriate individual plants or populations is a major bottleneck in plant research considering the complex nature of plant genome, such as heterozygosity, repetitiveness, and polyploidy. This challenge could be overcome by the old but effective method known as haploid induction. Haploid plants containing half of their sporophytic chromosomes can be rapidly generated mainly by culturing gametophytic cells such as ovules or pollens. Subsequent chromosome doubling in haploid plants can generate stable doubled haploid (DH) with perfect homozygosity. Here, classical methodology to generate and identify haploid plants or DH are summarized. In addition, haploid induction by epigenetic regulation of centromeric histone is explained. Furthermore, the utilization of haploid plant in the genomics era is discussed in the aspect of genome sequencing project and population genetic studies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.757-767
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• 1995

This experiment was done to determine the optimum concentration of IAA for root development in plants regenerated from the callus culture of barley embryos. Two concentrations of 2,4-D, 3ppm and 5ppm selected as an optimum among five different concentrations in the previous experiment were used for callus induction and proliferation in this experiment. For callus induction, 3ppm of 2,4-D produced 35.6% in immature embryos and 4.4% in mature embryos, while 5ppm gave 33.8% in immature and 5.6% in mature embryos. Out of 320 immature embryos cultured, 111 embryos were induced to calli and 684 plants were produced from them, while only 16 embryos were induced to calli from 320 mature embryos and 92 plants were restored. The rates of callusing and plant regeneration were 34.7%, 214% in immature embryos and 5.0%, 28.7% in mature embryos, respectively. The average root lengths and root numbers of plants restored from callus at five different IAA concentrations of 0ppm, Ippm, 5ppm, l0ppm and 30ppm were 7.9mm, 3.6; 18.4mm, 5.2; 16.1mm, 3.9; 8.5mm, 3.5 and 6.4mm, 3.4, while plants directly obtained from mature embryos were 14.8mm, 4.9; 4.9mm, 3.6; 4.3mm, 3.1; 3.6mm, 2.6 and 3.2mm, 2.1, respectively. Therefore, 1ppm gave the best result for the root. promotion in callus, whle 0ppm, a control, gave the largest root developmemt in embryos. High concentration of lAA(30ppm) in callus and any exogeneous supplement of lAA in embryos negatively affected to the root lengths and root numbers. Genotypic effect was also observed in given four varieties, Bruce, Klages, Olbori and Albori. For chromosome doubling, when 0.1% colchicine was applied on 428 plants under three different conditions such as air circulation, temperatures and growth stages, 319 plants of doubled haploids were obtained so that the rate was 74.5%