• Plant Biotechnology Reports
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• 제3권3호
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• pp.175-182
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• 2009

Simple, reproducible, high frequency, improved plant regeneration protocol in Eastern Cottonwood (Populus deltoides) clones, WIMCO199 and L34, has been reported. Initially, aseptic cultures established from axillary buds of nodal segments from mature plus trees on MS liquid medium supplemented with $0.25mg\;1^{-1}$ KIN and $0.25mg\;1^{-1}$ IAA. Nodal and internodal segments were found to be extra-prolific over shoot apices during course of aseptic culture establishment, while $0.25mg\;1^{-1}$ KIN concentration played a stimulatory role in high frequency plant regeneration. Diverse explants, such as various leaf segments, internodes, and roots from in vitro raised cultures, were employed. Direct plant regeneration was at high frequency of 92% in internodes, 88% in leaf segments, and 43% in root segments. This led to the formation of multiple shoot clusters on established culture media with rapid proliferation rates. Many-fold enhanced shoot elongation and growth of the clusters could be achieved on liquid MS medium supplemented with borosilicate glass beads, which offer physical support for proliferating shoots leading to faster growth in comparison to semi-solid agar or direct liquid medium. SEM examination of initial cultures confirmed direct plant regeneration events without intervening calli. In vitro regenerated plants induced roots on half-strength MS medium with $0.15mg\;1^{-1}$ IAA. Rooted 5- to 6-week-old in vitro regenerated plants were transferred into a transgenic greenhouse in pots containing 1:1 mixture of vermicompost and soil at $27{\pm}2^{\circ}C$ for hardening and acclimatization. 14- to 15-week-old well-established hardened plants were transplanted to the field and grown to maturity. The mature in vitro raised poplar trees exhibited a high survival rate of 85%; 4-year-old healthy trees attained an average height of 8 m and an average trunk diameter of 25 cm and have performed well under field conditions. The regeneration protocol presented here will be very useful for undertaking genetic manipulation, providing a value addition to Eastern Cottonwood propagation in future.

• Journal of Plant Biotechnology
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• 제50권
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• pp.176-182
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• 2023

사과 '후지'의 잎 절편체로부터 신초 기관형성을 통한 효율적인 식물체 재생 시스템을 확립하기 위하여 암처리 기간, 전처리 방법, 배양 용기당 치상 절편체 수, 배양 용기의 종류와 배지 위의 절편체 치상방향 등을 달리하여 실험을 실시하였다. 배양 초기 암조건에서의 배양은 신초 형성에 필수적이며, 4주 동안 배양한 후 명조건으로 옮겨 배양하는 것이 신초 재생에 가장 효과적이었다. 배양 전 전처리로는 sorbitol 40 g/L가 포함된 액체 재생배지에 2시간 동안 침지하였을 때 신초 형성율이 87.5%까지 증가하였으며, 신초 형성 시기가 빨라지는 것으로 나타났다. 배양 용기당 치상 절편체 수는 9개를 치상하는 것이 신초 재생에 효과적이었으며, 배양 용기는 100 ml 삼각플라스크를 사용하는 것이 petri dish를 사용하는 것에 비해 신초 형성율이 약 3배 정도 증가하였다. 잎절편체의 배지 위 치상방향은 배축면이 배지에 닿게 치상했을 때, 신초 형성율과 재생된 신초수가 다소 높게 나왔다. 암조건에서 4주간 배양한 후 명조건으로 옮겨총8주간 배양하여 재생된 신초는 1/4 MS에 0.2 mg/L의 IBA가 첨가된 배지에서 발근을 유도한 후 활착시켜 온실에서 재배하였을 때 정상적인 표현형을 보여주었다.

• 원예과학기술지
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• 제30권1호
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• pp.79-84
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• 2012

An efficient protocol for cryopreservation of madder hairy root cultures has been developed using droplet-vitrification. In previous study, combining loading solution C4 (35% PVS3) and vitrification solution B5 (80% PVS3) was the most effective method. In this study, we tried three types of vitrification solution, B5, A3 (90% PVS2, on ice), and A5 (70% PVS2, on ice). Combining loading solution C4 and vitrification solution A5 (on ice) showed the best regeneration rate in this study. Histological changes of the cells within the hairy root of madder were also observed in different steps. The cells from the hairy roots of the control treatment were full and intact with different size of vacuoles and obvious cell nucleus having a dark nucleolus. After the stage of preparing for cryopreservation (after preculturing, loading, followed by dehydration solution A5 or B5), intercellular spaces had become distinct, and within cells, the cytoplasms had become denser and week plasmolyses had appeared. The cell plasmolyses were much more apparent and we measured the degree of plasmolysis by calculating, the area of cell/the area of cytoplasm. The value of plasmolysis degree was the highest in the combination of preculture, loading solution C4, and dehydration solution A5, 1.97. Because the highest regeneration rates appeared in the treatment of A5 for 20 min, we could assume that the optimal degree of plasmolysis for cryopreservation might be around 1.97. The changes in cell structure during cryopreservation might be a useful basis for the development of a proper long-term preservation method for madder germplasms.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.333-339
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• 2007

Adequate bone quantity is one of the important factor to obtain osseointegration after implantation. Guided bone regeneration (GBR) has widely used in implantation for reconstruction of bony defects. Since introducing this procedure, there are many studies about survival rate of implants, changing in surrounding bone volume after function. The purpose of this study was to evaluate the amount of resorption according to placement timing and survival rate after function. The subjects were patients who had been operated with GBR from Jun 2003 to Jun 2004 in Seoul National University Bundang Hospital. They were divided into simultaneous and delayed placement group. The follow up had been performed at the time of just after GBR, 1, 3, 6, 12, 24-month later and standard periapical radiographs were taken to estimate the bone level at the time. The total average of bone level change in radiographs was 1.94mm(${\pm}0.25$), and 1.92mm(${\pm}0.72$) in simultaneous installation, 2.03mm(${\pm}0.25$) in delayed installation. In this report, the survival rates were 92.2% in simulataneous group and 92.3% in delayed group. Insufficient primary stability, early contamination of wound, overloading, poor oral hygiene, and infection were thought to be associated factors in the failed cases.

• 한국자원식물학회지
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• 제30권6호
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• pp.612-617
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• 2017

The preservation of pear germplasm, like that of other clonal germplasms, is difficult because it requires conservation of whole plants or their tissues. Among the currently available methods for long-term conservation of clonal germplasm, cryopreservation of shoot tips is the most reliable and cost- and space-effective option. Alginate-coated axillary shoot tips from in vitro-grown pear were conserved successfully in liquid nitrogen (LN) following dehydration. Shoot recovery from cryopreserved shoot tips was improved greatly after 8 weeks of cold acclimation, but recovery decreased slightly after then. The highest regeneration rate was observed when in vitro shoot tips were preincubated in MS (Murashige and Skoog) medium with 0.3 M sucrose for 48 h, and when alginate-coated shoot tips were precultured in MS medium with increasing sucrose concentrations (0.5 M and 0.7 M) for 8 and 16 h, respectively. When the encapsulated beads were dehydrated for up to 7 h [25% water content (fresh weight basis)] under laminar flow, the highest regeneration rate was observed in "BaeYun No. 3" (55.7%) and "Whanggeum" (43.3%) after warming from LN. This technique is useful as a practical procedure to cryopreserve plant material that is sensitive to freezing of the surrounding cryoprotectant medium. Therefore, this technique appears to be promising for the cryopreservation of shoot tips from in vitro-grown plantlets of pear germplasm.

• Journal of Plant Biotechnology
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• 제47권1호
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• pp.40-45
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• 2020

An efficient protocol for multiple shoot induction and plant regeneration from axillary bud culture of Magnolia 'Vulcan' was developed in the present study. Primary shoots were obtained from axillary bud explants cultured on Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BA). To induce multiple shoots effectively, primary shoot tips were cultured on MS medium supplemented with different concentrations of BA and zeatin at 0, 0.2, 0.5, and 1.0 mg/L. Of these treatments, the MS medium with 0.5 mg/L BA resulted in the highest number of shoots per explant with an average value of 5.9, and it produced the greatest shoot height at 4.8 cm after 12 weeks of culturing. In the rooting of in vitro produced shoots, the greatest percentage of explants forming roots (91.3%), number of roots per explant (9.7), and root length (2.8 cm) were obtained in half-strength MS medium supplemented with 6.0 mg/L indole-3-butyric acid (IBA). Regenerated plantlets were successfully acclimatized and hardened off inside the culture room with 87.5% survival rate. Plants were transferred to a greenhouse with a 97.2% survival rate. The highly efficient shoot multiplication and plant regeneration system reported herein can be used for large-scale clonal propagation of valuable Magnolia species or cultivars.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.15-15
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• 2019

The walnut (Juglans regia L.), a member of the Juglandaceae, is native to the mountain ranges of central Asia. This species of walnut is valued commercially for its nuts and in some areas for its timber. The seeds of walnut are recalcitrant and it has strong integument dormancy and their germination is irregular, making its natural propagation difficult. Low percentage of seed germination and long propagation cycle are the main problems of propagation. This study was conducted medium composition on in vitro plantlet regeneration from axillary buds of walnut. It has proved to be the most generally applicable and reliable method of in vitro propagation. Micropropagation culture that axillary buds are excised aseptically enables faster multiplication of plants. The axillary buds of walnut new cultivar "Sinlyeong" were cultured on two basal media which contained the different plant growth regulators depending on the respective shooting and rooting stage. After 12 weeks, the shoot generation rate was 85.3%, the shoot number and its length were 1.9/explant and 2.7 cm in the most favorable medium composition. The percentage of rooting was 25.4%. From these results, it was found the optimum basal medium and plant growth regulator for in vitro plant regeneration from axillary buds of walnut new cultivar "Sinlyeong". However, we have continued to search the other medium additives to enhance the rate of walnut root.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.23-23
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• 2021

Apple (Malus×domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. Tissue culture in vitro is a biotechnological technique that has been used to genetically improve cultivars (scions) and rootstocks. This could be important in the production of genetically uniform scions and rootstocks for commercial apple production. In nurseries, apple plants are produced by grafting scions onto rootstocks. The Cornell-Geneva (Geneva® series) breeding program has bred several dwarf rootstocks that are resistant to diseases and pests and are also cold hardy. This study was conducted to determine the optimal medium strength to improve sprouting shoot rate of apical meristem of the apple rootstocks of fire blight resistance. The apple rootstocks apical meristem at size (0.2 mm to 0.3 mm) with axillary buds were cultured on the MS(Murashige & Skoog) medium supplemented with plant growth regulators. The sprouting ratio and growth characteristics was evaluated after eight weeks in vitro culture. The highest rate of bud differentiation and shoot formation were 23.8% and 55.6%, respectively. After 6 weeks, shoots were regenerated from apical meristem, and their growth characteristics was significantly varied on the respective basal medium with different plant growth regulators. Our studies showed that the apple rootstocks the apple rootstocks of fire blight resistance plantlets could be successfully produced from apical meristem differentiated out of young twigs via organogenic regeneration.

• 한국자동차공학회논문집
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• 제15권3호
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• pp.72-78
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• 2007

A diesel particulate filter causes progressive increase in back pressure of an exhaust system due to the loading of soot particles. To maintain the pressure drop caused by DPF under proper level, a regeneration process is mandatory when excessive loading of soot is detected in the filter. It is a major reason why the relation between the amount of soot and the pressure drop in a DPF becomes crucial. On the other hand, pressure drop varies with not only the soot loading but also conditions of exhaust gas such as mass flow rate. Therefore, the relation among them becomes complicated. Furthermore, the characteristics of heat transfer in a DPF is another crucial parameter in order for the filter to avoid thermal crack during regeneration period. This study presents characteristics of pressure drop under various conditions of soot loading and mass flow rate in catalyzed diesel particulate filter. This study also shows characteristics of heat transfer in DPF when high temperature gas flows into the filter. Experiments reveal that the soot loading and mass flow rate affect characteristics pressure drop independently. Experiments also indicate that the amount of coating material has little influence on pressure drop with changes in soot loading and mass flow rate. However, increased catalyst coating may lead to the improved heat transfer which is efficiency to reduce thermal stress of the filter.

• 식물조직배양학회지
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• 제22권6호
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• pp.329-334
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• 1995

효과적인 형질전환 시스템을 이용하여 왜화유전자인 rolC 유전자를 구기자나무로의 형질전환 시스템을 확립하였다. 침으로 자극된 엽절편을 2.0 mg/L zeatin이 함유된 3/2 MS배지에 배양하였을 때 엽표면으로부터 줄기재분화가 되었다. 그러나 여러 농도의 kanamycin sulfate와 2.0 mg/L Aeatin이 함유된 배지에 엽절편을 배양하였을 때는 kanamycin sulfate의 농도가 증가할수록 줄기 유발수가 감소하는 것을 볼 수 있었으며, 적정선발농도는 10 mg/L이었다. 엽절편은 공동배양 시간에 따라서 생존율과 줄기재분화에 매우 큰 영향을 미쳤다. 엽절편의 생존율은 dipping할 경우가 가장 좋았으며, 배양시간이 길수록 엽절편의 백색화가 관찰되었고, 생존율이 급격히 감소하는 것을 볼 수 있었다. 줄기재분확에 가장 적합한 공동배양 시간은 24시간으로 나타났다. 공시균주와 24시간 동안 공동배양한 엽절편을 10mg/L의 kanamycin sulfate와 2.0 mg/L zeatin이 함유된 줄기 유도배지에 배양한 결과, 105개의 엽절편 중 80개의 엽절편이 생존하였으며, 그 중에서 15개의 재분화된 줄기를 얻었다. 재분화된 줄기들은 형질전환여부를 판명하기 위해 1차적으로 10 mg/L kanamycin sulfate가 함유된 배지에 옮겨 4 주간 배양한 결과, 항생제에 대해서 저항성을 가진 5개의 식물체를 선발할 수 있었다. 2차적으로 rolC유전자와 NPTII 유전자 도입의 유무를 검증하기 위하여 Southern 분석을 행한 결과, 구기자의 형질전환 식물체에서 rolC 유전자 probe의 coding sequence와 동일한 것으로 생각되는 1kb위치와 NPTII probe의 coding sequence와 동일한 것으로 생각되는 2.6kb 위치에서 각각의 밴드를 확인할 수 있었다.