Growth Inhibitors of Lettuce Seedlings from Curvibacter sp. GA75-1

Lam Hoang(황람),Gil-Jae Joo(주길재),Won-Chan Kim(김원찬),Eun-Ju Yang(양은주),Sang-In Kim(김상인),Sang-Man Lee(이상만),Jae-Ho Shin(신재호),In-Koo Rhee(이인구),Kyung-Sik Song(송경식) 한국원예학회 2009 원예과학기술지 Vol.27 No.2

식물생장억제제의 분리와 동정을 위하여 500여 종의 토양미생물로부터 상추 유묘에 대하여 강한 저해활성을 나타내는 미생물 균주 GA75-1을 선발하였다. 이 균주는 16S rRNA의 핵산염기서열 분석결과, Curvibacter sp.로 동정되었다. 이 균주의 배양 여액에 대하여 dichloromethane, ethyl acetate 및 butanol을 이용하여 순차적으로 분배한 다음, 강한 활성을 나타내는 butanol 가용성분획에 대하여 활성 지향형 분리를 통하여 화합물 1과 2의 두 가지 화합물을 분리하였다. 1과 2는 상추유묘의 뿌리 생장을 50㎎ L⁻¹에서 각각 56.8과 54.1% 저해하였으며, 줄기생장을 22.5 및 47.3% 저해하였다. 1과 2는 ¹H-NMR과 EI-MS 분석을 통하여 각각 uracil과 4-methoxybenzoic acid로 동정되었다. 1과 2는 50% 뿌리성장 저해농도 (IC₅₀) 값이 48.4와 49.1㎎ L⁻¹이었으며, 줄기에 대하여는 IC₅₀값이 각각 > 100.0와 51.3㎎ L⁻¹이었다. Uracil 유도체는 매우 잘 알려진 제초제 군에 속하나 uracil 자체에 대한 제초활성은 본 보고가 처음이며, 4-methoxybenzoic acid가 상추유묘에 대한 저해제로서 Curvibacter sp.에서 분리 보고된 것도 이번이 처음이다. 상기 화합물을 함유하는 Curvibacter sp. GA75-1은 식물의 도복 방지제, 또는 생물농약으로 이용될 수 있을 것으로 기대된다. The microbial strain GA75-1, which exhibited growth inhibitory activity on lettuce seedlings, was selected out of more than five hundred bacterial colonies by pot experiment for isolation and identification of plant growth retardants. The strain was identified as Curvibacter sp. by the nucleotide sequence of the 16S rRNA gene. The culture broth was consecutively partitioned with dichloromethane, ethyl acetate, and butanol. The bioassay-guided fractionation of butanol extract led to the isolation of compound 1 and 2 which inhibited 56.8 and 54.1% of lettuce root elongation and 22.5 and 47.3% of shoot growth at 50 ㎎ L⁻¹, respectively. From ¹H NMR and EI-MS spectra, 1 and 2 were identified as uracil and 4-methoxybenzoic acid, respectively. The concentrations of uracil and 4-methoxybenzoic acid required for 50% inhibition of root were 48.4 and 49.1 ㎎ L⁻¹ and of shoot were > 100.0 and 51.3 ㎎ L⁻¹, respectively. Uracil derivatives are one of very well-known herbicide groups; however, this is the first report on the herbicidal effect of uracil itself on lettuce. In addition, 4-methoxybenzoic acid is firstly isolated from the genus C. lanceolatus as an inhibitor of lettuce seedling growth. C. lanceolatus containing the above compounds is expected to be useful as the lodging-preventer and/or biotic herbicide.

사물 인터넷(IoT)을 이용한 통합 가전제어시스템

민상기(Sang-ki Min),김형준(Hyung-joon Kim),유한상(Han-sang Yoo),이승호(Seung-ho Lee),권람(Lam Kwon),박은찬(Eun-Chan Park) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.12

Short Communication : Mechanism by Which Bacillus-Derived 2-Aminobenzoic Acid Inhibits the Growth of Arabidopsis thaliana Roots

( Lam Hoang ),( Kyung Sik Song ),( In Koo Rhee ),( Jeong Hoe Kim ),( Sang Man Lee ) 한국식물학회 2007 Journal of Plant Biology Vol.50 No.4

To analyze the growth inhibitory mechanism of a 2-aminobenzoic acid (2-AA) derived from Bacillus cereus EJ-121, we treated Arabidopsis thaliana plants with 2-AA, 2-AA analogs, auxin (NAA), a known auxin transport inhibitor [2,3,5-triiodobenzoic acid (TIBA)], and an ethylene action inhibitor [silver thiosulfate (Ag)]. Root development was significantly inhibited by 50 Μm 2-AA, whereas the growth of bacteria and yeast was undeterred. The application of two 2-AA analogs - 3-aminobenzoic acid (3-AA) and 4-aminobenzoic acid (4-AA) - did not impair Arabidopsis root growth at concentrations below 100 μM. These results suggest that the effect of 2-AA is not due to its chemical structure, but because of its conversion to another metabolite, IAA. To confirm this, we supplemented TIBA in the growth medium, and found that the degree of inhibition was significantly reduced. Similarly, when plants were co-treated with 100 μM Ag, the negative effect of 50 μM 2-AA was greatly diminished. All of these observations support the proposal that this inhibition results from the conversion of 2-AA to IAA. Furthermore, the increased auxin level leads to a rise in ethylene synthesis, which then blocks root growth and, ultimately, retards overall plant development.

Improving Product Quality through Conflict Management: A Study of Hong Kong ODM Suppliers

Lam, Ping-Kit,Chin, Kwai-Sang The Korean Society for Quality Management 2004 The Asian Journal on Quality Vol.5 No.2

Client-supplier collaboration in new product development (NPD) has been a strategy in response to fierce global competition. Traditionally, Hong Kong suppliers collaborate with worldwide clients through original equipment manufacturing (OEM) arrangement in which suppliers manufacture products according to clients' design. In recent years, a growing number of Hong Kong suppliers have transformed to original design manufacturing (ODM) in which they are assigned a design responsibility other than manufacturing products. The ODM arrangement necessitates a close interaction between clients and suppliers, which brings about intense conflict. Conflict has been recognized as an important factor affecting NPD performance including product quality. This paper studies the conflict handling practices of Hong Kong ODM suppliers based on 87 survey data. The results show that the suppliers frequently adopt effective conflict handling practices by which they can develop products of good quality through better design decisions. The results also suggest that the use of ineffective conflict handling behaviors, particularly avoiding, should be reduced for better product quality.

Product Specification Management in Collaborative NPD: An Investigation of Problems and Good Practices in Electronics Industry

Lam, Ping-Kit,Chin, Kwai-Sang,Cheung, Wai-Ying The Korean Society for Quality Management 2006 The Asian Journal on Quality Vol.7 No.1

Client-supplier collaboration has been an imperative approach to new product development (NPD), in which a good product specification management system and practice is crucial to the assurance of product quality. This study investigates product specification management in client-supplier collaborative NPD. Based on the interviews and survey study, 12 problems and 13 good practices of product specification management are identified. It also compares the importance and degree of the implementation of the product specification practices in Hong Kong electronics industry. The results suggest that more intensive practices should be implemented for better product specification management.

New metformin derivative HL 156A prevents oral cancer progression by inhibiting the insulin‐like growth factor/AKT/mammalian target of rapamycin pathways

Lam, Thuy Giang,Jeong, Yun Soo,Kim, Soo‐,A,Ahn, Sang‐,Gun John Wiley and Sons Inc. 2018 CANCER SCIENCE Vol.109 No.3

<P>Metformin is a biguanide widely prescribed as an antidiabetic drug for type 2 diabetes mellitus patients. The purpose of the present study was to observe the effects of the new metformin derivative, HL156A, on human oral cancer cell and to investigate its possible mechanisms. It was observed that HL156A significantly decreased FaDu and YD‐10B cell viability and colony formation in a dose‐dependent way. HL156A also markedly reduced wound closure and migration of FaDu and YD‐10B cells. We observed that HL156A decreased mitochondrial membrane potential and induced reactive oxygen species (ROS) levels and apoptotic cells with caspase‐3 and ‐9 activation. HL156A inhibited the expression and activation of insulin‐like growth factor (IGF)‐1 and its downstream proteins, AKT, mammalian target of rapamycin (mTOR), and ERK1/2. In addition, HL156A activated AMP‐activated protein kinase/nuclear factor kappa B (AMPK‐NF‐κB) signaling of FaDu and YD‐10B cells. A xenograft mouse model further showed that HL156A suppressed AT84 mouse oral tumor growth, accompanied by down‐regulated p‐IGF‐1, p‐mTOR, proliferating cell nuclear antigen (PCNA) and promoted p‐AMPK and TUNEL expression. These results suggest the potential value of the new metformin derivative HL156A as a candidate for a therapeutic modality for the treatment of oral cancer.</P>

High Electrical Conductivity of Nutrient Solution and Application of Methyl Jasmonate Promote Phenylpropanoid Production in Hydroponically Grown Agastache rugosa

Sung Jin Kim,Jai Eok Park,Gwon Jeong Bok,Bashistha Kumar Kanth,Vu Phong Lam,Jong-SeokPARK 한국원예학회 2018 원예과학기술지 Vol.36 No.6

Agastache rugosa Kuntze, a perennial herb in the Labiatae family, is ubiquitous in Korean fieldsand is used as a wild vegetable and medicinal herb for traditional therapies. We measured theconcentrations of tilianin and acacetin, in hydroponically grown A. rugosa plants cultured innutrient solutions of various electrical conductivities (ECs) for four weeks and sprayed or not withdifferent concentrations of methyl jasmonate (MeJA). The total acacetin content of A. rugosashoots ranged from 41.17 mg/plant at 1.0 dS·m-1 to 50.00 mg/plant at 4.0 dS·m-1, but did not differsignificantly between treatments. Tilianin accumulation in A. rugosa at 2.0 and 4.0 dS·m-1 was 9.66and 8.64 mg/plant, respectively, values significantly greater than those observed at 1.0 dS·m-1. Thecombined effect of MeJA application and the EC of the nutrient solution influenced the productionof both tilianin and acacetin in appreciable amounts. The highest observed levels of tilianin were2.75 mg·g-1 at 4.0 dS·m-1, 2.49 mg·g-1 at 2.0 dS·m-1, and 1.62 mg·g-1 at 1.0 dS·m-1 after applicationof 20 μM MeJA. Similarly, the highest observed levels of acacetin were 33.81 mg·g-1 at 4.0 dS·m-1and 20.85 mg·g-1 at 2.0 dS·m-1 after application of 10 μM MeJA. We also evaluated the growthparameters of these plants. All growth parameters were affected by the EC of the nutrient solution. The greatest leaf length and width and the longest petiole, internode, and stem measurements wereobserved at 2.0 dS·m-1, but these values were lower at 4.0 dS·m-1. All root parameters increased withincreasing EC, peaking at 4.0 dS·m-1. Our results suggest that high EC nutrient solution togetherwith MeJA application provides optimum conditions for plant growth and accumulation of tilianinand acacetin in hydroponically grown A. rugosa.

Response of Nutrient Solution and Photosynthetic Photon Flux Density for Growth and Accumulation of Antioxidant in Agastache rugosa under Hydroponic Culture Systems

Sung Jin Kim(김성진),Kwon Jung Bok(복권정),Vu Phong Lam(푸동람),Jong Seok Park(박종석) (사)한국생물환경조절학회 2017 생물환경조절학회지 Vol.26 No.4

배초향은 항동맥경화나 항박테리아의 특성을 가지는 한약재에 널리 사용되는 영년생 약용식물이다. 연구의 목적은 수경재배에서 배양액의 종류와 PPFD값에 따른 배초향의 생장 및 항산화 물질의 변화를 조사하는 것이다. 배초향은 주야간 16:8 시간의 일장조건에서 150과 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD 조건과 일본원시(HES), 서울시립대(UOS), 유럽채소연구소(EVR), 오오츠카 배양액(OTS)을 이용하여 6주간 재배하였다. OTS 배양액조건에서 자란 배초향의 지상부 및 지하부 건물중은 다른 배양액 처리구와 비교하여 유의적으로 높았다. 배초향의 틸리아닌 함량은 OTS 처리에서 가장 높았으며 다음으로 EVR, HES, UOS 순서로 낮아졌다. 총 아카세틴의 함량은 EVR처리에서 가장 높았으나 OTS처리와는 유의적 차이를 보이지 않았다. 또한 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD 조건에서 자란 배초향은 PPFD 150처리구와 비교하여 유의적으로 생체중과 건물중이 증가하였으며 기능성 물질은 틸리아닌과 아카세틴의 함량도 높았다. 본 연구는 수경재배 방식을 이용하여 식물공장에서 배초향을 재배할 경우 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD 조건과 OTS 배양액 조건에서 경제적인 광원조건으로 최적 바이오매스 생산량과 틸라아닌과 아카세틴의 함량을 증가시킬 수 있을 것으로 제안한다. Agastache rugosa, is a perennial medicinal plant commonly used in Chinese herbalism, and may have anti-atherogenic and antibacterial properties. Here in this study, we investigated the growth and variations in antioxidant contents of A. rugosa in response to nutrient solution and photosynthetic photon flux density (PPFD) with artificial lighting for a hydroponics culture. Fluorescent light at 150, and 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD with a 16/8 (light/dark) photoperiod, combined with four different nutrient solutions [developed by Horticulture experiment station in Japan (HES), University of Seoul (UOS), Europe vegetable research center (EVR), Otsuka-house 1A (OTS)], were used in a hydroponics culture system for 6 weeks. The shoot and root dry weights of A. rugosa grown with the OTS were significantly higher than those of other nutrient solutions. The amount of tilianin was the highest grown with the OTS, followed by EVR, HES, and UOS. Total acacetin content was the highest in A. rugosa grown under EVR which was statistically similar with OTS. The A. rugosa grown under 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD produced higher fresh weight and both acacetin and tilianin contents than that grown under 150 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD. The present results suggested that OTS along with 200 μmol·m<SUP>-2</SUP>·s<SUP>-1</SUP> PPFD could be an optimum growing condition for better growth and higher accumulation of tilianin and acacetin contents in A. rugosa with hydroponic culture systems in a plant factory.

Wall-Following Control of a Two-Wheeled Mobile Robot

Tan Lam Chung,Trong Hieu Bui,Sang Bong Kim,Myung Suck Oh 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.8

Wall-following control problem for a mobile robot is to move it along a wall at a constant speed and keep a specified distance to the wall. This paper proposes wall-following controllers based on Lyapunov function candidate for a two- wheeled mobile robot (MR) to follow an unknown wall. The mobile robot is considered in terms of kinematic model in Cartesian coordinate system. Two wall-following feedback controllers are designed: full state feedback controller and observer-based controller. To design the former controller, the errors of distance and orientation of the mobile robot to the wall are defined, and the feedback controller based on Lyapunov function candidate is designed to guarantee that the errors converge to zero asymptotically. The latter controller is designed based on Busawon's observer as only the distance error is measured. Additionally, the simulation and experimental results are included to illustrate the effectiveness of the proposed controllers.

방사광 광전자 분광기를 이용한 Ni/SiC에서의 열처리 온도에 따른계면 구조 변화 연구

韓相允,金鐘奎,金起弘,金秀泳,李鐘覽 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.5

The changes in atomic bonding state at the interface of ultra thin Ni film (25 Å) with SiC were investigated as a function of annealing temperature using synchrotron radiation photoemission spectroscopy (SRPES). From these, the early stage in the reaction to form Ni silicide was examined. It was found that Ni_2Si began to form below 600℃. However, at 300℃ Ni atoms migrated on the surface of SiC, leading to the formation of Ni islands and the substrate is partially exposed, prior to the formation of Ni silicide. When Ni_2Si was formed, the binding energy of SiC bond was not changed, but work function of the contact layer was increased. This provides the evidence that Schottky barrier height was increased with the formation of Ni silicide via the increase in work function of contact layer.