• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.269-274
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• 1987

A laboratory experiment was conducted to find out the effect of inoculation with plant growth of associative $N_2$-fixing bacteria on the combination of eight different rice seedling with seven different associative $N_2$-fixing bacteria in which were isolated and identified from grasses and rice in saline and reclaimed saline paddy soil. Those were examined in N-free axenic culture medium. The result of this experiment exemplified the contribution of associative $N_2$-fixing bacteria to their host plant were varied much by the combination of rice cultivars and bacterial strains. Acetylene reduction ($N_2$-fixation) activity seems to be more variable with respect to the combination of rice cultivars and bacterial strains. The relationship between acetylene reduction activity and rice performance such as dry matter weight, plant height, root length, and number of root were statistically insignificant. However, in comparision with the control, the dry matter yield of Annapuruna was increased by inoculation of all the seven bacteria strains. Among the seven rice cultivars, the average acetylene reducing activity was the highest in Annapuruna, and Shingwang, and the lowest in IR-8 inoculated with Pseudomonas sp H8. Among the seven bacterial strains the highest acetylene reducing activity was obtained by the combination of Shingwang with Pseudomonas sp H8.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.3
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• pp.219-224
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• 1991

An acid tolerant R. meliloti "YA03" which was characterized through both acidified tube and pot soil experiment, was examined on its inoculation effect to alfalfa[Medicago sativa (L.)]cv. Vernal on hilly acid soil. It was conducted for 2 years to evaluate inoculation residual effect and there were two-fertilizer factors of nitrogen(0.8kg/10a) and lime(0,162kg/10a)as urea and $Ca(OH)_2$, respectively. The results obtained were summarized as follows : 1. In the 1st-year experiment, YA03 inoculated without nitrogen and lime application showed higher symbiotic effectiveness than check strains, YA026 and Rm2011 in nodule mass, $N_2$-fixing activity, and dry matter yield, but with N 8kg/10a application lower effectiveness than Rm2011. 2. In the 2nd-year experiment, Alfalfa dry matter yield by YA03 inoculation with N application(without lime) was 74% higher than that(276 kg/10a) in the 1st year, and the value showed 166%, 20%, and 21% increments as compared with noninoculated control(180kg/10a). YA026(399kg/10a), and Rm2011(397kg/10a), respectively. 3. In the 2nd-year experiment of N applicated plote(without lime), especially, YA03 showed higher shoot nitrogen(7.7kg N/10a/Yr.) fixed and soil rhizobial population($1{\times}10^4\;cells/g.\;soil$) than check strains. 4. On the basis of lime application, application effect of three major fertilizers with YA03 inoculation on alfalfa yield and soil rhizobial population was in the order of $N+P_2O_5+K_2O>P_2O_5+K_2O>P_2O_5+K_2O$. 5. On the whole, alfalfa yield by acid tolerant R. meliloti YA03 inoculation on hilly acid soil was enhanced with nitrogen application, and besides it appeared 44% higher with lime than without lime.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.1
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• pp.17-24
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• 2005

We experimented on growth in light and production of hydrogen and organic matters in dark fermentation by using C. reinhardtii. In the light, growth rate of C. reinhardtii following $CO_2$ fixation was proportional to consumption rate of nitrogen source. And the starch in cell was accumulated more when the period of culture was lengthened more. But the accumulation rate of starch in cell was decreased when the growth rate of cell become dull. In the dark fermentation, the production volume and production rate of hydrogen were the highest value in the mid exponential state among other states. The utilization efficiency of substrate was better in the early exponential state than other states. In production of organic matters, acetic acid didn't change remarkably and ethanol showed the highest value in early exponential state.

• Journal of Forest and Environmental Science
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• v.33 no.1
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• pp.22-32
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• 2017

An experiment was set to assess the effect of mixed plantings on initial growth and biomass yield of two common plantation tree species of Bangladesh namely Acacia auriculiformis (A) and Gmelina arborea (G). Study was carried out in the nursery bed of the Seed Research Laboratory and Nursery of Institute of Forestry and Environmental Sciences, Chittagong University (IFESCU), Bangladesh during February to November, 2015. The treatments consisted of two pure planting plots (100% A and 100% G) and five mixed planting plots (50%A: 50%G, 35%A: 65%G, 25%A: 75%G, 65%A: 35%G and 75%A: 25%G) of these two species. In nursery, seedlings were raised in a randomized blocks with four replicates of seven treatment plots. Periodic increments on height (cm), collar diameter (cm) and leaf/phyllode number of the seedlings was taken in every month and continued up to 10 months. The growth and biomass yield of seedlings were measured 10 months after the first seed was emerged. The effects of mixed plantation on growth and biomass were compared to that of seedlings grown in pure plantation. At the age of 10 months it was found that G. arborea seedlings were significantly tallest (240.13 cm) when planted with A. auriculiformis in a proportion of 25%A: 75%G, whereas A. auriculiformis were tallest in the pure 100% A plot, with an average mean height of 135.36 cm. Maximum collar diameter (1.38 cm) was recorded for G. arborea in the mixed plots 75%A: 25%G. Fresh and dry weight of shoots and roots of the seedlings were found significantly (p<0.05) highest in 50%A: 50%G plot for G. arborea. G. arborea also showed highest quality index when mixed with A. auriculiformis in a proportion of 50:50, with an average value of 8.96. The results revealed a positive correlation between seedling growth and various planting patterns.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.270-281
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• 2012

The bacteria B1-9 that was isolated from the rhizosphere of the green onion could promote growth of pepper, cucumber, tomato, and melon plants. In particular, pepper yield after B1-9 treatment on the seedling was increased about 3 times higher than that of control plants in a field experiment. Partial 16S rDNA sequences revealed that B1-9 belongs to the genus Pantoea ananatis. Pathogenecity tests showed non-pathogenic on kimchi cabbage, carrot, and onion. The functional characterization study demonstrated B1-9's ability to function in phosphate solubilization, sulfur oxidation, nitrogen fixation, and indole-3-acetic acid production. To trace colonization patterns of B1-9 in pepper plant tissues, we used $DRAQ5^{TM}$ fluorescent dye, which stains the DNAs of bacteria and plant cells. A large number of B1-9 cells were found on the surfaces of roots and stems as well as in guard cells. Furthermore, several colonized B1-9 cells resided in inner cortical plant cells. Treatment of rhizosphere regions with strain B1-9 can result in efficient colonization of plants and promote plant growth from the seedling to mature plant stage. In summary, strain B1-9 can be successfully applied in the pepper plantation because of its high colonization capacity in plant tissues, as well as properties that promote efficient plant growth.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.107-114
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• 2015

Endophytes provide multifarious benefits such as promotion of plant growth and yield, suppression of phyto-pathogens, phosphate solubilising and fixation nitrogen. A study has been carried out to explore growth promotion and antifungal activities of endophytes of mulberry (Morus spp.). Endophytic bacteria were isolated from mulberry plants and studied their cultural, morphological characters, growth promotion as well as their antifungal activity against Rhizoctonia bataticola and Fusarium oxysporum , two mulberry root rot associated pathogens. Except two isolates, all bacteria were colourless and the colony size of eight isolates was small. The margin of five isolates was irregular and the consistency of three isolates was creamy, six isolates was slimy and one was mucoid. Texture of seven isolates was convex and others were flat. Eight isolates were gram positive and the rest Gram negative, five were cocci and others were bacilli (rod shaped). Four isolates were motile and all were catalase positive and only three isolates were oxidase positive. Spore staining was positive only for two isolates. The growth promotion study showed that there was significant difference in root length and seedling length. The antagonistic effect of the bacterial isolates was tested against R. bataticola showed significant (p <0.05) influence of the bacteria, days after inoculation and their interaction on the inhibition of fungal growth. The isolate En-7 completely inhibited the fungus followed by En-5 (66.67%). The bacterial isolates significantly (p <0.05) inhibited growth of F. oxysporum in PDA. The mean inhibition was higher (70.45%) in case of En-7 followed by En-8 (68.65%) and En-10 (66.44%). The study reveals that some endophytic bacteria associated with mulberry have growth promotion and antifungal activity and could be explored for promotion of mulberry growth and managing root rot disease.

• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.13-17
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• 1985

Rhizobium japonicum isolates from all around Korea could be classified into two groups, i.e., acid producing fast-growers with 2.4 hour mean generation time and non-acid producing slow-growers in yeast extract-mannitol medium with 13.1 hour mean generation time. Tested fast-growers were higher in 6-phosphogluconate dehydrogenase activity than slow-growers were and used sucrose as carbon source whereas slow-growers did not. Fast-grower R4, R257, R278, showed tolerance even in 0.5M NaCl or above and the growth of all the strains tested were inhibited at below pH 4.5. Relative symbiotic activities of nitrogen fixation for these isolated with Glycine max cv. Jangyeobkong (commercial soybean cultivar mostly cultivated in Korea) ranged 0.1 to 2.0 comparing to that of R. japonicum L-259 (NRRL), without regard to their growth rate.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.106-111
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• 2015

Helicobacter pylori (H. pylori) survives in acidic and fluctuating pH conditions of the stomach. The pH effect on H. pylori proteins is important for the advanced understanding of its evolution and viability, although this bacterium has the molecular machinery that neutralizes the acidic condition. HP1492 is known as a conserved NifU-like protein from H. pylori. NifU is a nitrogen fixation protein that mediates the transfer of iron-sulfur (Fe-S) cluster to iron-sulfur proteins like ferredoxin. Commonly, the monomeric reduced state of NifU can be converted to the dimeric oxidized state by intermolecular disulfide bond formation. Because it remains unclear that HP1492 actually behaves as known NifU protein, we first found that this protein can adopt both oxidized and reduced forms using size exclusion chromatography. Circular dichroism experiment showed that HP1492 is relatively well-structured at pH 6.5, compared to other pH conditions. On the basis of the backbone resonance assignment of HP1492, we further characterized the residues that are sensitive to pH using NMR spectroscopy. These residues showing large chemical shift changes could be mapped onto the secondary structure of the protein. Our results could provide the foundation for structural and biophysical studies on a wide spectrum of NifU proteins.

• Korean Journal of Microbiology
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• v.30 no.1
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• pp.30-36
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• 1992

nif (nitrogen fixation)-H.D, K genes of Frankia sp. SNU 014201. a symbiotic strain isolated from root nodule of Alnus hirsura, were found to be located in the genome on 13.5 kb of EcoRI, 18.0 kb of BamHI, 10.5 kb of BglII and 4.5 kb of KpnI fragments. Using EMBL-3 BamHI arms of bacteriophage lambda. the genomic library was constructed. from which fourteen recombinant phage nif-clones were selected. Among them, Ahnif-I2 had insert DNA of 18 kb, in which 7.9 kb of BamHl fragment contained nif-H, D, K and 3.6 kb of HindlIl/KpnI had nif-H and partial -D. Therefore, the 7.9 kb and 3.6 kb fragments were subcloned and partial restriction maps were constructed. As the results, nif-F1, D.K genes were found to be located continuously on the 6.5 kb of HindII/BamHI and 5.2 kb of SalIIBamHI fragment in the genome of Frankia sp. SNU 014201.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.1-12
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• 2012

The present study examines the effects of 30 mg/kg butachlor on the cyanobacterial diversity of rice fields in Eastern Uttar Pradesh and Western Bihar in India. A total of 40 samples were grouped into three classes [(i) acidic, (ii) neutral, and (iii) alkaline soils], based on physicochemical and principle component analyses. Acidic soils mainly harbored Westillopsis, Trichormus, Anabaenopsis, and unicellular cyanobacteria; whereas Nostoc, Anabaena, Calothrix, Tolypothrix, and Aulosira were found in neutral and alkaline soils. Molecular characterization using 16S rRNA PCR and DGGE revealed the presence of 13 different phylotypes of cyanobacteria in these samples. Butachlor treatment of the soil samples led to the disappearance of 5 and the emergence of 2 additional phylotypes. A total of 40 DGGE bands showed significant reproducible changes upon treatment with butachlor. Phylogenetic analyses divided the phylotypes into five major clusters exhibiting interesting links with soil pH. Aulosira, Anabaena, Trichormus, and Anabaenopsis were sensitive to butachlor treatment, whereas uncultured cyanobacteria, a chroococcalean member, Westillopsis, Nostoc, Calothrix, Tolypothrix, Rivularia, Gloeotrichia, Fischerella, Leptolyngbya, and Cylindrospermum, appeared to be tolerant against butachlor at their native soil pH. Butachlor-induced inhibition of nitrogen fixation was found to be 65% (maximum) and 33% (minimum) in the soil samples of pH 9.23 and 5.20, respectively. In conclusion, low butachlor doses may prove beneficial in paddy fields having a neutral to alkaline soil pH.