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Bacterial Exopolysaccharides: Insight into Their Role in Plant Abiotic Stress Tolerance

  • Bhagat, Neeta;Raghav, Meenu;Dubey, Sonali;Bedi, Namita
    • Journal of Microbiology and Biotechnology
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    • v.31 no.8
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    • pp.1045-1059
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    • 2021
  • Various abiotic stressors like drought, salinity, temperature, and heavy metals are major environmental stresses that affect agricultural productivity and crop yields all over the world. Continuous changes in climatic conditions put selective pressure on the microbial ecosystem to produce exopolysaccharides. Apart from soil aggregation, exopolysaccharide (EPS) production also helps in increasing water permeability, nutrient uptake by roots, soil stability, soil fertility, plant biomass, chlorophyll content, root and shoot length, and surface area of leaves while also helping maintain metabolic and physiological activities during drought stress. EPS-producing microbes can impart salt tolerance to plants by binding to sodium ions in the soil and preventing these ions from reaching the stem, thereby decreasing sodium absorption from the soil and increasing nutrient uptake by the roots. Biofilm formation in high-salinity soils increases cell viability, enhances soil fertility, and promotes plant growth and development. The third environmental stressor is presence of heavy metals in the soil due to improper industrial waste disposal practices that are toxic for plants. EPS production by soil bacteria can result in the biomineralization of metal ions, thereby imparting metal stress tolerance to plants. Finally, high temperatures can also affect agricultural productivity by decreasing plant metabolism, seedling growth, and seed germination. The present review discusses the role of exopolysaccharide-producing plant growth-promoting bacteria in modulating plant growth and development in plants and alleviating extreme abiotic stress condition. The review suggests exploring the potential of EPS-producing bacteria for multiple abiotic stress management strategies.

A Case Study of an ENACT Model-based Engineering Design Online Course for Fostering Social Responsibility of Engineers (사회적 책임의식 함양을 위한 ENACT 모형 기반 기초설계 교과목의 비대면 수업 운영 사례)

  • Kim, Gahyoung;Ok, Seung-Yong;Lee, Hyunju;Ko, Yeonjoo;Hwang, Yohan
    • Journal of Engineering Education Research
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    • v.24 no.6
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    • pp.3-19
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    • 2021
  • This study aimed to introduce a case study of a basic engineering design course using the ENACT model for fostering social responsibility of engineers, and to investigate the educational effects of the course. Since the ENACT model was designed to encourage STEM college students to pursue responsible problem solving based on their understanding of socioscientific issues, we assumed that it would be beneficial for engineering students to foster their social responsibility as well as their understanding of science/engineering-related issues. A total of 49 engineering students who enrolled in the course participated in the study. Data included students' course artifacts, reflection papers, and responses to survey questionnaires. Results indicated that the students became more aware of nature of science and technology after the program, and began to solve the problems while considering the views of multiple stakeholders. They highly valued the experience of communicating with others as engaging in the civic activities. They also expressed high satisfaction and feeling of achievement on the course learning. We expect the ENACT model to be an effective teaching guideline that fosters the social responsibility of engineering students and furthermore, engineering ethics.

Genetic Characteristics of Dill(Anethum graveolens L.)

  • Seon Wha Bae;Song Mun Kim;Ki Yeon Lee;Kyung Dae Kim;Jae Hee Lee;Eun Ha Jang;Jin Gwan Ham
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.319-319
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    • 2022
  • Dill(Anethum graveolens L.) is a buttercup family, and flowers, leaves, stems, and seeds are all mainly used as spices. This study was carried out to discover and propagate genetic resources for the development of plant-derived medicinal fragrance materials, and to establish a database. In order to investigate the genetic characteristics of dill and to extract natural essential oils, 50 resources were parceled out the genetic resource center, sown, germinated, and then formally cultivated in the test research field. After sowing and propagation of 50 dill resources, the characteristics of each individual such as plant height, the diameter of polychasium during flowering, and the number of small inflorescences were investigated. The flowering period of dill was around May 31 to June 17, and about 10% of the proliferating population flowered around May 31. The plant length of dill was 32-14 lcm, and the length of petiole was 1~16cm, showing an average of 5cm. The color of the stem and leaf color was referred to the RHS Color chart, and the colors were classified as 44S, 19 V, and 75DI. Uses as many resources as possible with 35 resources equivalent to 19V. Inflorescences are lateral and opposite, polychasium inflorescences are somewhat flat at the upper part and have a diameter of 4.5~20cm, and divergent inflorescences are irradiated with 5~86 multiple flowers. The number of pedicels is 16-74, and the length of the pedicel is 1-18cm spread sideways or the length is different from each other.

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Different Metabolic Patterns of Parkinsonism: Analysed by Statistical Parametric Mapping (통계적 파라미터를 이용한 Parkinsonism의 Metabolic pattern 분석)

  • 주라형;김재승;최보영;문대혁;서태석
    • Progress in Medical Physics
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    • v.14 no.2
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    • pp.108-123
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    • 2003
  • The purpose of this study is to evaluate the contribution of $^{18}$ F-FDG brain PET in the differentiating Idiopathic parkinson's diesease (IPD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA). We studied 24 patients with parkinsonism : 8 patients (mean age 67.9$\pm$10.7 y: M/F : 3/5) with IPD, 9 patients (57.9$\pm$9.2 y : M/F : 4/5) with MSA and 7 patients (67.6$\pm$4.8 y : M/F 3/4) with PSP. All patients with parkinsonism and 22 age-matched normal controls underwent $^{18}$ F FDG PET in 3D mode after the injection of 370 MBq $^{118}$ F FDG. The patients with IPD, MSh and PSP were compared with a normal control group by a two-sided t-test of SPM99 (uncorrected P<0.001, extent threshold>100 voxel). All three parkinsonism groups, showed significant hypometabolism in the cerebral neocortex compared to the normal control group. However, the three groups displayed different metabolism in the subcortical structure, brain stem, and cerebellum. In IPD, there was no significant hypometabolism in the putamen, brain stem and cerebellum. However, MSA patients showed significant hypometabolism in the striatum, pons, and cerebellum compared to the normal controls and IPD patients. In addition, PSP showed significant hypometabolism in the caudate nuclei, the thalamus, midbrain, and the cingulate gyrus compared to the normal controls, the IPD, and MSA groups (IPD vs Normal sensitivity/specificity : 75%/l00%, MSA vs Normal sensitivity/specificity :100%/87%, PSP vs Normal sensitivity/specificity : 86%/94%). Our results show that the regional metabolism of IPD, MSA, and PSP is different mainly in the striatum, thalamus, brain stem and cerebellum. An assessment of the $^{18}$ F-FDG PET scan images using SPM may be a useful adjunct to a clinical examination in making a differential diagnosis of Parkinsonism.

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Development of Forest Volume Estimation Model Using Airborne LiDAR Data - A Case Study of Mixed Forest in Aedang-ri, Chunyang-myeon, Bonghwa-gun - (항공 LiDAR 자료를 이용한 산림재적추정 모델 개발 - 봉화군 춘양면 애당리 혼효림을 대상으로 -)

  • CHO, Seung-Wan;KIM, Yong-Ku;PARK, Joo-Won
    • Journal of the Korean Association of Geographic Information Studies
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    • v.20 no.3
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    • pp.181-194
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    • 2017
  • This study aims to develop a regression model for forest volume estimation using field-collected forest inventory information and airborne LiDAR data. The response variable of the model is forest stem volume, was measured by random sampling from each individual plot of the 30 circular sample plots collected in Bonghwa-gun, Gyeong sangbuk-do, while the predictor variables for the model are Height Percentiles(HP) and Height Bin(HB), which are metrics extracted from raw LiDAR data. In order to find the most appropriate model, the candidate models are constructed from simple linear regression, quadratic polynomial regression and multiple regression analysis and the cross-validation tests were conducted for verification purposes. As a result, $R^2$ of the multiple regression models of $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}$ among the estimated models was the highest at 0.509, and the PRESS statistic of the simple linear regression model of $HP_{25}$ was the lowest at 122.352. $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}-based$ models, thus, are comparatively considered more appropriate for Korean forests with complicated vertical structures.

Mechanical Properties of Cryptomeria japonica by the Differences of Stand Characteristics in Southern Region of Korea (남부지역 삼나무의 임분 특성에 따른 역학적 특성)

  • Hong, Nam-Euy;Won, Kyung-Rok;Yoo, Byung-Oh;Jung, Soo-Yung;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.3
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    • pp.320-326
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    • 2015
  • Mechanical properties of woods are easily affected by the differences of site environment such as soil and climate changes. In this study, the relationship between mechanical properties and growth factors for Cryptomeria japonica stands in Jeollanam-do Province, Gyeongsangnam-do Province and Je-ju island was analyzed. From these plot data, bending strength, compressive strength, and shear strength were analyzed by Duncan's new multiple range test. The results of Duncan's new multiple range test analysis indicated that bending strength, compression strength, and shear strength were positively related to tree mean height, and stem number per ha, respectively, while they were inversely proportional to DBH (diameter at breast height), elevation, and soil drainage. As a result of this study, there are high correlations between mechanical properties of wood and stand characteristics of Cryptomeria japonica by the region, this findings are very useful to apply the silvicultural treatment system to produce high quality timber as a basic data on this species (distributed in southern region of Korea).

In vitro shoot propagation of Ranunculus kazusensis Makino, an endangered aquatic plant (멸종위기 수생식물인 매화마름(Ranunculus kazusensis Makino)의 기내 신초 증식)

  • Park, Min Wan;Ryu, Shi Hyun;Nam, Su Hwan;Bae, Kee Hwa
    • Journal of Plant Biotechnology
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    • v.44 no.3
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    • pp.325-329
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    • 2017
  • A micropropagation method via callus for Ranunculus kazusensis Makino, an endangered species, was established. When stem segments were cultured on MS media supplemented with 1.0 mg/L IAA, NAA, IBA and 2,4-D, the highest frequency of callus induction was achieved on MS medium supplemented with 1.0 mg/L NAA. Multiple shoot per explant was obtained, the MS medium containing 1.0 mg/L BA and 0.5 mg/L NAA. Additionally, effect of activated charcoal (AC) and sucrose on shoot growth in in vitro culture were examined. The most suitable conditions for shoot growth after 4 weeks of culture were the MS medium with AC and sucrose. This in vitro propagation protocol will be valuable for conservation and mass propagation of this endangered plant.

Selective Beam Shielding Method of Gamma-Knife Unit Using Various Plugging Patterns (다양한 Plugging 형태를 이용한 감마나이프의 선택적 빔 차폐 방법)

  • Jang Geon Ho;Lim Young Jin;Shin Dong Oh;Choi Doo Ho;Hong Seong Eon;Leem Won
    • Radiation Oncology Journal
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    • v.11 no.2
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    • pp.439-448
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    • 1993
  • The B-type gamma knife unit was installed at Kyung-Hee University Hospital in March 1992. The selective beam plugging method can be used to reduce the low percentage isodose profiles of normal sensitive organ and to modify the isodose curves of treatment volume for better shaping of the target volume. For representing the changes of the low percentage isodose profiles, the variations of dose distribution for several cases were discussed in this paper. The film dosimetry was peformed for the evaluation of calculated isodose profiles predicted by KULA dose planning system. The results were verified by RFA-3 automatic densitometry. The clinical application of selective beam shielding method was peformed in 17 patients in 100 patients who have undergone gamma knife radiosurgery for a year. The calculated and the measured isodose profiles for the high percentage regions were well consistent with each other. When the target of pituitary tumor is macro-size, the selective beam shielding method is the most applicable method. When the target size, however, is small, the correct selection of the proper helmet size is very important. All patients were exposed almost about 3~12 Gy for brain stem, and 3~11.2 Gy for optic apparatus. It is recommended that the same or other plugging patterns with multiple isocenters should be used for protection of the radiosensitive normal structures with precise treatment of CNS lesions.

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Microprogation And Environment Conditions Affecting On Growth Of In Vitro And Ex Vitro Of A. Formosanus Hay

  • Ket, Nguyen-Van;Paek, Kee-Yoeup
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2002.11a
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    • pp.29-30
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    • 2002
  • The goal of this research was to develop the effectiveness of in vitro culture method for A. formosanus and study the environment in vitro conditions affecting on growth. The first series of experiments were examined to investigate the response of three different basal media, MS (Murashige and Skoog, 1962), Knudson (KC; Knudson, 1946) and modified hyponex on growth and multiplication during in vitro culture. Multiple shoot proliferation was induced in shoot tip explants on Hyponex (H3) media supplemented with BA (1 mg1$\^$-1/) or TDZ (1-2 mg1$\^$-1/). Addition of activated charcoal (1%) to the TDZ containing medium promoted rapid shoot tip proliferation (11.1 shoots per explant) but the same medium had an opposite effect resulting in poor proliferation in the nodal explants. However, the regenerated shoots had slow growth rate and failed to elongate. This problem was overcome by transferring the shoot clumps to a hormone free H3 media supplemented with 2% sucrose and 0.5% activated charcoal. Using bioreactor culture for scaling up was also shown the best way for multiple shoot induction and growth of this plant. The second series of experiments was studied to investigate the effect of physical environment factors on growth of in vitro plantlets. The Anoectochilus formosanus plantlets were cultured under different air exchange rate (0.1, 0.9, 1.2h$\^$-1/), without sucrose or supplement 20g.1$\^$-1/ (photoautotrophic or photomixotrophic, respectively), and different photosynthesis photon flux (40, 80, 120 ,${\mu}$mol.m$^2$.s$\^$-1/- PPF). Under non-enrichment CO$_2$ treatment, slow growth was observed in photoautotrophical condition as compared with photomixotrophical condition on shoot height, fresh weigh and dry weight parameters; High air exchange (1.2.h-l) was found to be inadequate for plant growth in photomixotrophical condition. On the contrary, under CO$_2$, enrichment treatment, the plant growth parameters were sharply (visibly) improved on photoautotrophic treatments, especially on the treatment with air exchange rate of 0.9.h-1. The growth of plant in photoautotrophic condition was not inferior compared with photomixotrophic, and the best growth of plantlet was observed in treatment with low air exchange rate (0.9.h-1). Raising the PPF level from 80 to 120${\mu}$mol.m$\^$-2/.s$\^$-1/ decreased the plant height, particularly at 120${\mu}$mol.m$\^$-2/.s$\^$-1/ in photoautotrophic condition, fresh weight and dry weight declined noticeably. At the PPF of 120${\mu}$mol.m$\^$-2/,s$\^$-1/, chlorophyll contents lowed compared to those grown under low PPF but time courses of net photosynthesis rate was decreased noticeably. Light quality mainly affected morphological variables, changes of light quality also positively affected biomass production via changes in leaf area, stem elongation, chlorophyll content. Plant biomass was reduced when A. formosanus were grown under red LEDs in the absence of blue wavelengths compare to plants grown under supplemental blue light or under fluorescent light. Stem elongation was observed under red and blue light in the present experiment. Smaller leaf area has found under blue light than with other lighting treatments. Chlorophyll degradation was more pronounced in red and blue light compared with white light or red plus blue light which consequent affected the photosynthetic capacity of the plant. The third series of experiment were studied to investigate the effect of physical environment factors on growth of ex vitro plants including photosynthesis photon flux (PPF), light quality, growing substrates, electrical conductivity (EC) and humidity conditions. In the present experiments, response of plant on PPF and light quality was similar in vitro plants under photosynthesis photon flux 40${\mu}$mol.m,$\^$-2/.s$\^$-1/ and white light or blue plus red lights were the best growth. Substrates testing results were indicated cocopeat or peat moss were good substrates for A. formosanus growth under the greenhouse conditions. In case of A. formosanus plants, EC is generally maintained in the range 0.7 to 1.5 dS.m-1 was shown best results in growth of this plant. Keeping high humidity over 70% under low radiation enhanced growth rate and mass production.

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Studies on the Cropping system of the Field Crop in Chungnam Area (충남지방(忠南地方)의 전작물(田作物) 작부체계확립(作付體系確立)에 관(關)한 연구(硏究))

  • Choi, Chang Yeol;Kim, Dal Ung;Lee, Jae Chang;Kim, Young Rae
    • Korean Journal of Agricultural Science
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    • v.3 no.1
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    • pp.39-51
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    • 1976
  • As an accempt to increase thc efficiency of land use and the food production to achieve the national goal in the food self-sufficiency, nine cropping systems on the upper-land were examined in pure-stand and in mixtures of soybean, corn, potato and radish. The important conclusions of this study were summarized as follows; 1. The flowering date of soybean was two or three days earlier in pure-stand than in the mixture with corn. The maturing date two days earlier in the pure-stand than in the mixture with corn. The flowering and maturing dates were not different among various cropping systems in corn. 2. The stem length of soybean was significantly different among various cropping systems. Soybean in pure-stand was shorter in stem length than with corn. 3. The number of pods per soybean plant did not give any significant differences among various cultivation methods. 4. The length of internode and the number of nodes per soybean plant in the mixture with corn were greater than in the pure-stand. In the number of branches per plant this was reversed. 5. The average stem dry weight of soybean per 10a was not significantly different among various cultivation methods. 6. The soybean yield per 10a in the pure-stand was obviously greater than the mixture and there were significant differences among cultivation method within the mixture with corn in soybean yield. 7. The 1,000-grain weight of soybean was significantly different and those in the pure-stand was heavier than those in the mixture with corn. 8. Grain weight per soybean plant and the stem diameter in the pure-stand were significantly lesser than those in the mixture with corn. 9. In the comparisons of corn in the pure-stand and in the mixture with soybean, plant height, number of ear per 10a, mean ear weight and remember of grain per plant, 100-grain weight, ear length, ear girth and number of ear pel plant were not significantly different among various cultivation methods except for the grain yield per 10a. 10. In the economic analysis, the mixture with soybean and corn gave the greatest gross income. The combination 7 was the best which was 47.6% increase income comparing with the soybean pure-stand. 11. As it can be assumed, soybean plant was influenced greatly than corn by various cropping system. It is necessary to study more complex cropping system finding and giving more desirable multiple cropping system for the farmer.

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