• Microbiology and Biotechnology Letters
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• v.21 no.2
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• pp.95-100
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• 1993

Effect of dual inoculation with vesicular-arbuscular(VA) mycorrhizal fungi, Glomus mosseae, and Rhizobium meliloti R455 on growth, nodulation, and nitrogenase activity of alfalfa (Medicago sativa L. cv. Vernal) were examined in pot experiment. After 63 days growth, shoot length, number of leaf, and leaf size of alfalfa were increased as as result of dual inoculation with Glomus mosseae and Rhizobium meliloti. Total dry weight of alfalfa plant was increased 1.4 times compared to single inoculation with Rhizobium meliloti. Nodule number and mean fresh weight of nodule per plant were also increased due to the mycorrhizal infection.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.19-49
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• 1987

Recent development of recombinant DNA techniques such as gene cloning and DNA sequencing has led to understanding of genetic information coded on plant genes and their application to crop improvements. Nuclear genes so far isolated and characterized at the molecular level from various plants are those involved mainly in photosynthesis, nitrogen fixation, seed development and defensive responses to environmental stresses. Most of plant genes contain intervening sequences (introns) flanked with GT and AG, as it typical of animal genes. The 5' flanking regions of plant gene revealed the presence of promoter elements such as TATAAA and CCAAT, which have been identified at animal genes to be involved in transcrip- tion initiation. The 3' untranslated regions include a sequence similar to AATAAA whcih functions as a polyadenylation signal in other eukaryotic genes. Furthermore, enhancer-type sequences were found at the 5' flanking regions of various plant genes. This indicates that the structure of plant genes is very similar to animal genes and mechanisms governing the synthesis and processing of mRNAs may be identical in higher eukaryotes. However, genes expression studies involving transformation revealed their differ ences within plants and between plant and animal systems.

• Journal of Ginseng Research
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• v.46 no.1
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• pp.1-10
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• 2022

Ginseng has been well-known as a medicinal plant for thousands of years. Bacterial endophytes ubiquitously colonize the inside tissues of ginseng without any disease symptoms. The identification of bacterial endophytes is conducted through either the internal transcribed spacer region combined with ribosomal sequences or metagenomics. Bacterial endophyte communities differ in their diversity and composition profile, depending on the geographical location, cultivation condition, and tissue, age, and species of ginseng. Bacterial endophytes have a significant effect on the growth of ginseng through indole-3-acetic acid (IAA) and siderophore production, phosphate solubilization, and nitrogen fixation. Moreover, bacterial endophytes can protect ginseng by acting as biocontrol agents. Interestingly, bacterial endophytes isolated from Panax species have the potential to produce ginsenosides and bioactive metabolites, which can be used in the production of food and medicine. The ability of bacterial endophytes to transform major ginsenosides into minor ginsenosides using β-glucosidase is gaining increasing attention as a promising biotechnology. Recently, metabolic engineering has accelerated the possibilities for potential applications of bacterial endophytes in producing beneficial secondary metabolites.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.1-7
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• 1978

Laboratory and pot experiment were carried out to find the symbiotic nitrogen fixing activities and the yield of dry matter on the several selected wild soybean plant. 1. Very high acetylene reducing(nitrogen fixing)activities were observed in isolated strains of Rhinchosis volubilies Lour. (924 nmole), Desmodium oldhami Oliver (844 nmole) and Glycine soja s. et z. (271 nmole/test tube/hr) while Rhizobium japonicum was only 0.6 nmole/test tube/hr. 2. On the serological reaction, eight isolated Rhizobium strains were sufficiently different to distinguish from the Rhizobium japonicum. 3. On the pot experiment with Glycine soja s. et z., A. Number of total nodules were higher in NPK+rice straw+Ca+Mo than in NoPK. However, little differences were observed in mumber of effective nodules. B. Yield of dry matter was increased with increasing of nitrogen content in plants. C. Estimated amount of fixed nitrogen in plant by an individual nodule was higher in NoPK than in NPK+rice straw+Ca+Mo.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.44-50
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• 1981

A pot experiment was conducted to find the nitrogen fixing activities associated with ice rhizoplane in nine varieties at various growth stage by acetylene reduction technique. Results obtained ware Summarized as follows. 1. Nitrog en fixing activites associated with rice rhizoplane differ by the rice variety and the growth stage. The activities increased with progressing of growing time, and maximum activities were obtained from the ear forming stage to the heading stage. 2. The application of rice straw did not greatly enhanced the nitrogen fixing activities associated with rice rhizoplane. However, somewhat increasing tendency was obtained in the Kataktara, TKM-6, Centrypartna. Daegujo, and Jodongji varieties. 3. The nitrogen fixed during the one rice cropping period was estimated as 0.55kg of N per 10a by Milyang-23 variety to 2.6kg of N per 10a by Jodongji variety. 4. The amount of rice root showed no significant relationship with the amount of nitrogen fixed during the growing period of rice plant.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.391-396
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• 1992

Anabaena variabilis A TCC 29413. a photoautotrophic and nitrogen fixing cyanobacteria. was investigated on the environmental factors regulating the growth and nitrogen lixation activity. A good growth of cyanobacteria] cells was observed due to nitrogen t1xation by the heterocyst differentiation in nitrogen free Allen and Arnon (]/8) medium. The nitrogenase activity was appeared to be in proportion to the cell growth lor 6 days then drastically decreased in the later growth period when the nitraTe was accumulated to high level in the culture to cause the inhibition. The optima] conditions lilr the cell growth and nitrogenase activity of A. varillbili.l were anaerobic. IO.OO0 lux. $30^{\circ}C$ and pH 8 with the nitrogen Cree minimal medium. The activity was significantly inhihited by the low concentrations of ammonium and nitrate. but was stimulated b) the ]ow Ieve] of phosphate and carbonate sources. The treatments of several toxic heavy metals showed strong inhibition of the cell growth and nitrogenase activity by O.3~10 ppm in the order of $Hg^{2+}$ > $Cd^{2+}$ > $Co^{2+}$ > $Zn^{2+}$ > $Ph^{2+}$, and the concentrations for 50% inhibition of the maximum activity were 0.41. 0.47. 0.5 L 0.66 and 8.1 ppm. respectively. The addition of carbohydrates (0.5~ 1.0%) in the dark condition stimulated the growth and activity in the order of sucrose > fructose > glucose.

• Journal of Life Science
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• v.13 no.4
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• pp.473-480
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• 2003

We analyzed the patterns of mineral ions and growth responses among symbiotic nitrogen fixing legumes by external nitrogen applications under salt gradients. Glycine max, Phaseolus angularis and Albizzia julibrissin showed remarkable growth inhibition above 40 mM NaCl treatments, but Cassia tora did not exhibit any visible injury symptom up to 100 mM NaCl treatments. As to ionic pattern, the $Na^+$ and $Cl^-$contents in leaves of G. max, P. angularis and A. julibrissin progressively increased with higher contents of external salinity. Compared to other plants, C. tora excluded $Na^+$more efficiently and maintained rather constant ionic contents in spite of high salt levels. With a few exception, these 4 legume plants exhibited better growth by the external nitrogen supply rather than the contribution of symbiotic nitrogen fixation only under saline condition.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.101-107
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• 2008

Bio-filtration utilizes microorganisms fixed to a porous medium to metabolize pollutants present in an air stream. The microorganisms grow in a bio-film on the surface of a medium or are suspended in the water phase surrounding the medium particles. Therefore, bio-filter support media play one of the most important key roles in bio-filtration of gas phase pollutants. To characterize and select the appropriate support media, gas adsorption capacity and microorganism immobilization were investigated in lab-scale experiments for the selected target support media which were compost I (compost from lab-scale process), compost II (compost from municipal facility), bark, wood chip, orchid stone and vermiculite. As odor materials, ammonia and trimethylamine were utilized. From the result of experiments, bark was superior to any other support media tested in adsorption capacity as much as 12.5 mg ammonia per 1 g bark. In trimethylamine adsorption, bark and wood chip showed a remarkable results of 21.1 and 14.1 mg/g respectively. On the other hand, microorganism fixation test determined by the count of nitrogen oxidizing microbes population, the compost II and wood chips showed the best results. Considering the characteristics of materials and the operating condition of the bio-filter, bark, wood chip, and compost II are applicable to the support media of bio-filter when they are appropriately blended on the basis of studying the media pH, packing porosity and moisture contents.

• Research in Plant Disease
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• v.18 no.3
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• pp.201-209
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• 2012

The multi-function of 18 Bacillus subtilis isolates collected from agricultural extension centers of local government and National Academy of Agricultural Science was investigated by measuring their antifungal activities against five plant pathogens, such as Rhizoctonia solani, Colletotrichum acutatum, Fusarium oxysporum, Magnaporthe oryzae and Phytophthora capsici, phosphorus solubilization ability, production of indole acetic acid (IAA) and siderophore, and nitrogen fixation. The B. subtilis isolates showed antifungal activity against several plant pathogens and nitrogen fixation activity, and produced siderophore and IAA. They could control pepper powdery mildew (Leveillula taurica), but there was no difference in control efficacy among the B. subtilis isolates. In fields, the control efficacy of B. subtilis R2-1 ($10^8$ cells/ml) was compared with two microbial fungicides, Q-pect and Topsid. In 2009, the control efficacy of B. subtilis R2-1 (37.7%) was lower than that of Topsid (47.6%), but higher than that of Q-pect (25.7%). In 2010, the control efficacy of B. subtilis R2-1 (83.3%) was higher than that of Topsid (67.9%). In order to elucidate mode of action of B. subtilis R2-1 for controlling pepper powdery mildew, spore germination rates of pepper powdery mildew pathogen collected on treated leaves was investigated when suspensions of B. subtilis R2-1 and two microbial fungicides (Q-pect and Topsid) were foliar-sprayed. They highly suppressed spore germination of the pathogen with inhibition values of 84.2% for B. subtilis R2-1, 97.9% for Q-pect and 94.7% for Topsid. Further study on the mass-culturing method and formulation is needed for development of a microbial fungicide.

• Journal of Embryo Transfer
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• v.17 no.3
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• pp.211-218
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• 2002

These studies were carried out to investigate the effects of the addition of amino acids and FBS as source of exogenous nitrogen fixation added to medium on in vitro production of blastocyst derived from bovine follicular oocytes. The base medium was TCM-199 solution for in vitro maturation(IVM) of bovine follicular oocytes and Fer-TALP solution for in vitro fertilization(IVF) and YS solution for in vitro culture(IVC). IVC used the fertilized oocytes of 24-hr culture (day 1) after IVF. Rmbryos were cultured in drop-culture that contained 25 embryos per 10 ${mu}ell$. The results obtained are as follows: 1 The developmental rates of fertilized oocytes to blastocyst that developed from YS solution with NEAA derived from MEM alone were higher than those of YS solution without NEAA. 2. The developmental rates of fertilized oocytes to blastocyst that developed from YS solution with EAA derived RPMI 1640 alone were significantly higher than those of YS solution without EAA (p<0.05). 3. When added to EAA on day 5 after NEAA supplementation on day 1, the developmental rates of hatched blastocyst and blastocyst to hatched blastocyst were improved. 4. When removed to EAA on day 3, day 4 and day 5 from medium after NEAA and EAA supplementation on day 1. the developmental rates of blastocyst to hatched blastocyst were reduced. 5. When added to FBS as source of exogenous nitrogen fixation, the developmental rates of blastocyst and hatched blastocyst that developed from the later culture higher(day 5) than those of the early culture.