• Journal of Plant Biology
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• 제17권3호
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• pp.127-136
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• 1974

The effect of potassium metabolism on the soybean leaves was studied with comparison of other elements during the successive growing period. The results were as follows; 1. The percentage of potassium content showed remarkable increase not only in the first compound leaf at a stage which was growing vigorously and producing new leaves, but also in the fifth compound leaf at a stage which was taking a active metabolism of nitrogen and carbohydrate but not producing new leaves. However, the percentage of potassium content was decreased in the second compound leaf than in the first one. Such a result could be regarded as a potassium removal from mature leaves into immature and flowing out from stoma through respiration. During the pod-development the percentage of potassium content in the soybean leaf was decreased. 2. If nitrogen, phosphorus and potassium were added excessively in the nutrient solution, the percentage of potassium content in the soybean leaf had increased. The effects of these elements showed a remakable increase in the excessive plot of nitrogen than in that of phosphorus. At early stage the redtarded effect of phosphorus on the growth of soybean could be covered by potassium, however, at late stage it could not. The growth of soybean plant was much more inhibited by potassium, compared with nitrogen and phosphorus. New leaves could not be produced in the potassium deficient soybean plant after the third compound leaf. The normal growth of soybean plant could not be observed if only one element was excessively added to the culture solution, compared with the deficiency of other two elements.

• 한국잡초학회지
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• 제14권3호
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• pp.192-198
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• 1994

잡초병원균 Drechslera portulacae가 생산하는 식물독소를 단리하여 그 화학구조를 결정한 결과, zeaenol으로서 동정하였다. Zeaenol은 기지 물질이나 지금까지 입체화학적인 면에서는 불명인 채 남아있었으며, 본 연구에서 처음으로 그 입체구조를 명백하게 하였다. 또한, 잡초방제적인 측면에서 식물독소의 활용가능성을 찾기 위하여 zeaenol의 제초활성을 조사하였다. 그 결과, 식용피 및 어저귀의 유묘의 초장에 대한 억제효과는 보여주지 않았으나, $3{\times}10^{-5}M$의 처리구에서 식용피 및 어저귀의 유근의 생장을 대조구에 비해 각각 22.8%, 54.8% 억제하였다.

• 식물조직배양학회지
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• 제25권2호
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• pp.89-93
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• 1998

Tomato phenylalanine ammonia-lyase 5 (tPAL5) was identified that alternate initiation sites were utilized differentially in response to environmental stimuli (Lee et al, 1992b). In this study, we tried to look into tissue -or cell- specific expression pattern of tPAL5 gene by fusing with ${\beta}-glucuronidase$ (GUS) gene in transgenic tobacco plants. In transgenic plants, root and stem extracts contained 8~12 fold higher levels of GUS activity than petiole or leaf tissue while the highest levels of induction was observed from leaf tissue by mechanical wounding (5~11 fold). In trans-sections of stems and petioles, GUS activity was restricted to phloem cells(outer region) of developing vascular bundle and mainly at apical tip region in the root tissues. The levels of GUS activity was drastically reduced (10~12 fold reduction) when the 5'-upstream region of tPAL5 gene (-1151bp from ATG codon) was deleted up to -665. The levels of GUS expression, however, raised up by 6~8 fold when deleted up to -455. Therefore, we conclude that there are positive cis-elements at the region -1151 to -1008 and at -455 to -195 while the negative cis-element is at -1008 to -455.

• 한국유기농업학회지
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• 제19권spc호
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• pp.251-254
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• 2011

Botrytis cinerea infects stems and leaves of greenhouse tomatoes and can cause serious economic losses. This study was conducted to develop environment-friendly control method against tomato gray mold. Antagonistic microorganisms (bacteria) were screened for control activity against Botrytis cinerea, both in vitro and in vivo, using stem sections. One hundred bacterial strains were isolated from the rhizospheric soil of various plants including tomato. These strains were screened for growth inhibition of Botrytis cinerea on agar plate by the dual culture and thirty strains showing strongly inhibitory effect against the pathogen were selected first. Among thirty strains, JB 5-12, JB 22-2, JB 22-3, U 4-8 and U46-6 reduced significantly disease incidence, when applied simultaneously with the pathogen. These results suggested that five antagonistic bacteria strains selected have the potential to control tomato gray mold in organic farming.

• Journal of Plant Biology
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• 제30권3호
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• pp.205-213
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• 1987

Soybean, inoculated with effective Rhizobium japonicum 110, were grown by sand culture with nutrient solution containing either of 0, 1, 3, 10 or 30mM NO3-/l, and analyzed growth characteristics, NR activity, N2-fixation activity, and changes of ureide contents during the growing period. The amount of nodule formation decreased abruptly by nitrate treatment, the maximum nodule dry weight was 1.59, 1.05, 0.78, 0.09 and 0.008 g plant-1, respectively for each treatment on the 98th day. Specfic activity of N2-fixation showed the maximum rates of 140, 101, 37, 5 and 2.2 nM dw.mg-1.hr-1, respectively for each treatment in the earlier growth period. The maximum acetylene reduction activity on the 98th day after sowing was 81.5, 35.3, 14.3, 0.1 and 0.0045 $\mu$M C2H4 plant-1.hr-1, respectively for 0, 1, 3, 10 and 30 mM of NO3- gradients. Nitrate reduction activity increased along with nitrate gradients, and decreased abruptly with age. Relative abundance of ureides in plant organs was high in reproductive growth, and showed the maximum value in fully symbiotic dependent plant. Relative abundance of ureides in stem is a useful indication for the evaluation of nitrogen fixation in nodules of symbiotic plant.

• International Journal of Contents
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• 제15권2호
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• pp.53-58
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• 2019

The aim of this paper is to discuss how designers lead and direct 'technology-driven society' using their creative communication skill. To this end, it is required for communication designers to take conscious steps to recognize the future direction of their profession. Despite the advancement in technology, there is a human being at the center of all design activities. From a certain point of view, contemporary communication design takes an open-ended exploration of the subject matter, rather than a finished output. The notion of creative leadership may potentially expand more in terms of improving the methodology of today's visual culture. The paper will examine creative leadership that could be proposed by the challenge of discourse upon the upcoming industrial revolution. Today, communication designers are confronted by new leadership opportunities and challenges. Some leading designers seem to focus on brand new media technologies to prepare the 4th industrial revolutions. However, communication design cannot be discussed in the medium but can be understood as a process. Top-down and bottom-up process is always a concerned about the relationship since the focus of leadership has changed. In the top-down process, the leadership has existed between 'designer and client' because designers have played their role as a problem solver. On the other hand, there is a different model of leadership between 'design and technology' based on bottom-up process, which stem from the design authorship. In this regard, the new definition of creative leadership in the $4^{th}$ industrial revolution proposes a designer as a problem-finder based on the relationship between the 'designer and the public'.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.52.1-52.11
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• 2020

Objectives: Yttria-stabilized tetragonal phase zirconia has been used as a dental restorative material for over a decade. While it is still the strongest and toughest ceramic, its translucency remains as a significant drawback. To overcome this, stabilizing the translucency zirconia to a significant cubic crystalline phase by increasing the yttria content to more than 8 mol% (8YTZP). However, the biocompatibility of a high amount of yttria is still an important topic that needs to be investigated. Materials and Methods: Commercially available 8YTZP plates were used. To enhance cell adhesion, proliferation, and differentiation, the surface of the 8YTZP is sequentially polished with a SiC-coated abrasive paper and surface coating with type I collagen. Fibroblast-like cells L929 used for cell adherence and cell proliferation analysis, and mouse bone marrow-derived mesenchymal stem cells (BMSC) used for cell differentiation analysis. Results: The results revealed that all samples, regardless of the surface treatment, are hydrophilic and showed a strong affinity for water. Even the cell culture results indicate that simple surface polishing and coating can affect cellular behavior by enhancing cell adhesion and proliferation. Both L929 cells and BMSC were nicely adhered to and proliferated in all conditions. Conclusions: The results demonstrate the biocompatibility of the cubic phase zirconia with 8 mol% yttria and suggest that yttria with a higher zirconia content are not toxic to the cells, support a strong adhesion of cells on their surfaces, and promote cell proliferation and differentiation. All these confirm its potential use in tissue engineering.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.279-288
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• 2007

In the present study, we focused on stem cells in the dental papilla of the tooth germ. The tooth germ, sometimes called the tooth bud, is the primordial structure from which a tooth is formed. The tooth germ consists of the enamel organ, the dental papilla, and the dental follicle. The dental papilla lies below a cellular aggregation of the enamel organ. Mesenchymal cells within the dental papilla are responsible for formation of dentin and pulp of a tooth. Tooth germ disappears as a tooth is formed, but that of a third molar stays in the jawbone of a human until the age of 10 to 16, because third molars grow slowly. Impacted third molar tooth germs from young adults are sometimes extracted for orthodontic treatment. In the present study, we evaluated the osteogenic activity and mineralization of cultured human dental papilla-derived cells. Dental papillas were harvested from mandible during surgical extraction of lower impacted third molar from 3 patients aged 13-15 years. After passage 3, the dental papilla-derived cells were trypsinized and subsequently suspended in the osteogenic induction DMEM medium supplemented with 10% fetal bovine serum, 50 g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate at a density of $1\;{\times}10^6\;cells/dish$ in a 100-mm culture dish. The dental papilla-derived cells were then cultured for 6 weeks and the medium was changes every 3 days during the incubation period. Dental papilla-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 7 of culture period, then decreased in intensity during the culture period. ALP mRNA level was largely elevated at 1 weeks and gradually decreased with culture time. Osteocalcin mRNA expression appeared at day 14 in culture, after that its expression continuously increased in a time-dependent manner up to day 28. The expression remained constant thereafter. Runx2 expression appeared at day 7 with no detection thereafter. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. Osteocalcin secretion was detectable in the culture medium from 1 week. The secretion of osteocalcin from dental papilla-derived cells into the medium greatly increased after 3 weeks although it showed a shallow increase by then. In conclusion, our study showed that cultured human dental papilla-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.627-633
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• 2016

단수수[Sorghum bicolor (L)]는 당류가 풍부한 사탕수수, 사탕무와 같은 주요 바이오연료 작물 중의 하나이다. 단수수 착즙액은 단수수 줄기를 압착하여 추출하며 주요 성분는 glucose와 fructose 그리고 sucrose로 구성되어 있다. 에탄올은 효모발효공정을 통하여 단수수 착즙액으로부터 쉽게 생산할 수 있다. 단수수 착즙액은 당류 뿐만 아니라 질소나 인산과 같은 다양한 무기영양원도 함유하고 있어 종균 배지로 활용성이 높다. 상업적인 에탄올 생산 공정에서 종균배양은 중요한 발효공정 중의 하나이며 공정비용 절감을 위해 최적화된 배지가 필수적이다. 본 연구에서는 섬유질계 바이오에탄올 생산을 위한 종균의 배지로서 단수수 착즙액의 특성을 평가하였다. 단수수착즙액의 발효기질 적합성을 평가하기 위해 YPD 및 억새 당화액을 비교하여 실험하였으며, YPD배지 중 yeast extract 와 peptone은 각각 5 g/L의 농도로 사용하였다. 각각의 기질들은 당 농도가 2%, 5%, 10%가 함유되도록 제조하여 발효를 통한 균체농도를 측정하였다. 그 결과 YPD와 단수수착즙액을 배지로 사용하였을 때 발효 24시간 후에 최대 $2.5{\times}10^8CFU/mL$ 이상의 균체농도를 나타내었다. 결과적으로 단수수착즙액은 12시간 발효 후에 $1.0{\times}10^8CFU/mL$ 균체를 생산하여 섬유질계 바이오에탄올 생산을 위한 종균 배지로서 YPD를 대체하여 사용할 수 있음을 확인하였다.

• IMMUNE NETWORK
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• 제1권1호
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• pp.87-94
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• 2001

목적 : 제대혈의 조혈모세포 체외확장 시 조혈세포 증폭과 더불어 조혈미세환경의 변화가 일어난다. 이때 제대혈 $CD34^+$ 세포에서 유래되는 지지세포의 계열 분석조혈성장인자 분비능력을 알아보고 지지세포 증식 조건을 확립하여 효과적인 제대혈의 체외증폭을 제시하고자 하였다. 방법 : 제대혈부터 $CD34^+$ 세포를 분리하여 실험에 사용하였다. 무혈청배지에서 각종 조혈성장인자를 다양한 조합으로 첨가하여 배양하였고 증식정도는 현미경으로 관찰하여 배양용기를 점유한 면적 비율로 계산하였다. 세포외간질 단백의 효과를 분석하기 위하여 collagen S, fibronectin, laminin 및 poly-L-ly sine를 미리 coating한 용기에 배양하여 분석하였다. 제대혈 $CD34^+$ 세포를 조혈성장인자의 첨가 없이 3주간 액체배양하였다. 배양 시, 1주, 2주 및 3주에 상층액을 얻어 $-80^{\circ}C$에 보관하였다가 한꺼번에 IL-3, IL-6, GM-CSF, IL-$1{\beta}$ 및 TNF-$\alpha$등을 ELISA 방법으로 내부적으로 분비되는 량을 측정하였다. 분화된 지지세포의 계열을 분석하기 위해 E-selectin, VCAM-1, ICAM-1, PECAM-1, vWF, vimentin 및 CD 14 항체를 이용하여 면역화학염색 후 형광현미경으로 관찰하였다. 결과 : 제대혈 $CD34^+$ 세포 체외증폭시키는 과정에서 배양 4일에 지지세포가 출현하기 시작하여 7-10일이 지나면서 증식하기 시작하였고 14-2 1일 경에 서로 뭉치는 양상을 보여주었다. 제대혈 $CD34^+$ 세포 배양하면서 내부적으로 분비되는 GM-CSF, IL-6의 측정치는 시간이 지남에 따라 증가되었다. 제대혈 $CD34^+$ 세포 체외확장 시 지지세포의 증식 정도는 TPO+FL+SCF+LIF의 조합의 조혈성장인자가 첨가되었을 때 그리고 세포외간질 단백 성분 중 1% poly-L-lysine으로 처리한 경우 가장 효과적이었다. 결론 : 체외 증폭시 제대혈 $CD34^+$ 세포로부터 지지세포가 나타났으며 적절한 조혈성장인자의 첨가나 세포외간질 단백의 첨가에 의해 증폭될 수 있다.