• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• 식물분류학회지
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• 제42권2호
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• pp.150-156
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• 2012

작은귀이끼과(Lejeuneaceae)에서 우리나라 미기록 태류식물 6 종을 발견하였다. 거제도에서 생육하는 응달이끼(Archilejeunea kiushiana), 가야산에 생육하는 칼잎이끼 (Drepanolejeunea angustifolia)와 동굴작은귀이끼(Lejeunea otiana), 완도 상황봉 계곡에 생육하는 계곡작은귀이끼(Lejeunea aquatica), 설악산 소청봉 부근에 생육하는 산토끼이끼 (Leucolejeunea japonica) 그리고 가거도에 생육하는 섬이끼(Spruceanthus semirepandus)를 국내 미기록 태류식물로 보고한다.

• 식물분류학회지
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• 제43권4호
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• pp.252-262
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• 2013

캄보디아 캄폿주 프놈보콜국립공원에 대한 식물상 조사 중 열대성 전기생식물인 B. fungosa var. indica를 발견하였다. 이들의 숙주를 확인하기 위해 숙주의 뿌리와 더불어 주변에 위치한 목본 식물을 채집하였으며, 이들을 DNA barcoding 방법을 사용하여 동정하였다. DNA barcode 마커로는 엽록체 rbcL 및 matK 유전자 구간을 적용하였으며, 15개의 숙주 뿌리와 7개의 주변 목본식물로부터 성공적으로 PCR 증폭 및 염기서열을 확보하였다. 숙주 뿌리로부터 얻어진 숙주의 염기서열은 앵초과, 노박덩굴과, 도금양과, 그리고 물푸레나무과로 식별되었으며, 주변의 목본식물은 물푸레나무과, 도금양과, 무환자나무과, 장미과, 물레나물과, 철쭉과와 녹나무과였다. 속 수준에서 앵초과는 Myrsine, 노박덩굴과는 Euonymus, 도금양과는 Syzygium, 물푸레나무과는 Olea 등으로 각각 식별되었으나, 종 수준에서의 동정은 불가능하였다. 앵초과 Myrsine와 물푸레나무과 Olea는 본 연구를 통해 최초로 B. fungosa var. indica의 숙주로 확인되었다. 추가적인 채집 조사 및 비교 연구, DNA barcoding을 통해 해당 지역의 생물다양성과 Balanophora속 식물의 숙주 식물 및 진화에 대해 좀더 명확하게 확인이 가능할 것으로 판단된다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.24-24
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• 2021

The Cassava (Manihot esculenta Crantz) is one of the major food crops in the tropical or subtropical regions. Recently, clean planting materials of improved cassava cultivars are in high demand. Problems in the propagation of cassava are virus vulnerable and low rates of seed germination. Thus, the study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. So we tried to optimize protocols for mass production from axillary buds of Cassava. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with axillary buds, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, axillary buds approximately 1 cm in length were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate showed 55.6%. The shoot number and its length was 1.0/explant and 2.3 cm in the most favorable medium composition. The auxin β-indolebutyric acid(IBA) 0~2.0 mg/L was proved to be effective on root development. Plantlets with fibrous roots easily generated tuberous roots in vitro. The tuberous roots were induced only when both kinetin and IBA were used in combination. after 8 weeks, the root generation rate showed 100%. The root number and its length was 17.2/explant and 2.2 cm in the most promising medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• 대한한의학방제학회지
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• 제15권1호
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• pp.175-183
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• 2007

This study was conducted to evaluate the inhibitory effects of Yongseollan(YSL) on the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-activated RAW264.7 cells. YSL is tropical plant originating from Mexico. The biological activity of this plant is not yet evaluated systematically. The aim of the present work is to investigate a potential anti-inflammatory activity of YSL. The RAW264.7 cells were cultured in D MEM/F12 medium for 24 hrs. After serum starvation, cells were treated with YSL for 1 hr, followed by stimulating NO production with a LPS. We found that YSL has an inhibitory effect on the production of NO, iNOS expression and $phospho-I{\kappa}B$ expression. YSL also inhibited tumor necrosis factor $(TNF)-{\alpha}$, interleukin (IL)-6, and $IL-1{\beta}$. Moreover, YSL inhibited cyclooxygenase (COX)-2 expression and prostanglandin E2 (PGE2). These findings showed that YSL could have some anti-inflammatory effects which might play a role in therapy in Gram-negative bacterial infections.

• International Journal of Industrial Entomology and Biomaterials
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• 제30권1호
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• pp.26-30
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• 2015

Tropical Tasar culture is forest and agro-based activity that covers agricultural and industrial activity. Tasar silk is produced by the silkworm, Antheraea mylitta which is polyphagous in nature. A large number of pests are reported to attack both the host plant as well as silkworm. As the rearing is conducted outdoor silkworms are exposed to attack of various pests during their life cycle. Eocanthecona furcellata (Hemiptera: Pentatomidae) is the major predator of tasar silkworm during young age rearing. Both nymphs and adults of the stink bug suck the heamolymph of silkworm leading to death. The present work was undertaken to study the life cycle of E. furcellata on larvae of vapourer tussock moth which is a major pest of tasar host plants. The incubation period, nymphal duration and total developmental period from egg to adult was $8.0{\pm}0.45d$, $16.0{\pm}3.24$ and $22.0{\pm}4.20d$, respectively. Pre-oviposition, oviposition and longevity of male and female stink bug was $3.20{\pm}0.38$, $17.60{\pm}1.86$, $42.40{\pm}1.94$, $37.00{\pm}3.18d$, respectively. Analysis of the data revealed no significant difference in life cycle of the predator when provided silkworm and vapourer tussock moth larvae as hosts. Which clearly indicates that E. furcellata can multiply on vapourer tussock moth larvae during non rearing periods. Adoption of recommended pest control measures for defoliators of tasar host plants during non-rearing periods will help in reducing the incidence of host plant pests and also in reducing the incidence of stink bug during rearing season. During the study it was also observed that larvae semilooper, boll headed caterpillar and nymphs of leaf hopper serve as alternate/secondary hosts to E. furcellata during non rearing seasons.

• Journal of Ecology and Environment
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• 제43권2호
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• pp.202-211
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• 2019

Oceanic islands are biologically important for their unique assemblages of species and high levels of endemism and are sensitive to environmental change because of their isolation and small species source pools. Habitat destruction caused by human landscape development is generally accepted as the main cause of extinction on islands, with exotic species invasion a secondary cause of extinction, especially on tropical islands. However, secondary impacts of human development (e.g., general degradation through resource use and exotic species introduction) are understudied on temperate islands. To determine secondary impacts of human development on the understory vegetation community, 90 field sites on Ulleung Island, South Korea, were sampled during the summer of 2016. Understory vegetation was chosen as it is a proxy for ecosystem health. Diversity and percent cover of introduced, native, and endemic species were tested against proximity to developed areas and trail usage using a model selection approach. Diversity was also tested against percent cover of three naturalized species commonly found in survey plots. The main finding was that distance to development, distance to town, and trail usage have limited negative impacts on the understory vegetation community within best-supported models predicting native and introduced cover and diversity. However, endemic species cover was significantly lower on high usage trails. While there are no apparent locally invasive plant species on the island at the time of this study, percent cover of Robinia pseudoacacia, a naturalized tree species, negatively correlated with plot diversity. These findings indicate that forests on Ulleung Island are not experiencing a noticeable invasion of understory vegetation, and conservation efforts can be best spent preventing future invasions.

• The Plant Pathology Journal
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• 제30권4호
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• pp.416-424
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• 2014

Sweet potato is grown extensively from tropical to temperate regions and is an important food crop worldwide. In this study, we established detection methods for 17 major sweet potato viruses using single and multiplex RT-PCR assays. To investigate the current incidence of viral diseases, we collected 154 samples of various sweet potato cultivars showing virus-like symptoms from 40 fields in 10 Korean regions, and analyzed them by RT-PCR using specific primers for each of the 17 viruses. Of the 17 possible viruses, we detected eight in our samples. Sweet potato feathery mottle virus (SPFMV) and sweet potato virus C (SPVC) were most commonly detected, infecting approximately 87% and 85% of samples, respectively. Furthermore, Sweet potato symptomless virus 1 (SPSMV-1), Sweet potato virus G (SPVG), Sweet potato leaf curl virus (SPLCV), Sweet potato virus 2 ( SPV2), Sweet potato chlorotic fleck virus (SPCFV), and Sweet potato latent virus (SPLV) were detected in 67%, 58%, 47%, 41%, 31%, and 20% of samples, respectively. This study presents the first documented occurrence of four viruses (SPVC, SPV2, SPCFV, and SPSMV-1) in Korea. Based on the results of our survey, we developed multiplex RT-PCR assays for simple and simultaneous detection of the eight sweet potato viruses we recorded.

• Parasites, Hosts and Diseases
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• 제56권5호
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• pp.477-485
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• 2018

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.

• 식물분류학회지
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• 제41권1호
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• pp.58-65
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• 2011

우리나라 미기록 종인 닭의장풀과(Commelinaceae)의 고깔닭의장풀(Commelina benghalensis L.)과 큰닭의장풀(Commelina diffusa Burm. f.) 2종이 제주도의 저지대에서 채집되었다. 고깔닭의장풀은 불염포의 밑 부분이 합생하여 깔때기 모양을 하고 폐쇄화를 갖는다는 점에서 나머지의 다른 종들과 구분이 된다. 큰닭의장풀은 삭과가 3개의 과피편으로 되어 있고, 불염포상 총포편이 피침형이면서 심장저 또는 원저라는 점에서 나머지 다른 종들과 구분된다. 염색체수는 고깔닭의장풀이 2n = 2x = 22(2배체)이며, 염색체 크기가 1.25-2.70 ${\mu}m$로 매우 작았고, 큰닭의장풀은 2n = ca. 100 이상으로 정확한 수를 알 수 없었다. 이 종들은 지금까지는 아시아와 아프리카의 열대 및 아열대에 분포하여 우리나라보다 남쪽에만 분포하는 것으로 알려져 왔다.