• Korean Journal of Microbiology
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• v.38 no.1
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• pp.45-49
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• 2002

Bradyrhizobium japonicum is a soil bacterium with a unique ability to infect the roots of leguminous plants and establish a nitrogen-fixing symbiosis, which has been used as a microbial manure. In this study, we examined the stress response after pretreatment of cells with cold temperature. When pre-treated with cold temperature ($4^{\circ}C$) for 16 hr, B. japonicum increased the viability in subsequent stress-conditions such as alcohol, $H_2O_2$, heat, and dehydration. For cold adpatation, cultured B. japonicum was exposed to $4^{\circ}C$. Upon subsequent exposure to various conditions, the number of adapted cells pretreated by cold adaptation was 10-1000 fold higher than that of non-adaptated ones. It appeared de novo protein synthesis occurred during adaptation, because a protein synthesis inhibitor, chloramphenicol abolished the increased stress tolerance. By using a degenerate PCR primer set, a csp homolog was amplified from B. japonicum genome and sequenced. The deduced partial amino acid sequence of the putative Csp (Cold shock protein) shares a significant similarity with known Csp proteins of other bacteria.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.110-113
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• 1995

Transposon Tn5 was used to induce random insertional mutations in Bradyrhizobium japonicum, a soybean endosymbiont. By genomic Southern blot analysis, transposition events were found to have occurred randomly throughout the B. japonicum genome. After screening 3, 626 mutants by auxotrophy test, a histidine auxotroph was isolated. Upon plant infection test, the His mutant showed a 3~4 day delay in nodule formation.

• Current Research on Agriculture and Life Sciences
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• v.15
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• pp.25-32
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• 1997

This study was carried out to research the biological characteristics among rhizobia and soybean seed and root lectins, and to obtain a basic imformation of host specificity in biological nitrogen symbiosis system. The results obtained were as follows: Purified seed lectin from soybean varieties of paldal, backwoon and hwangkeum formed immunoprecipitin lines with standard soybean seed lectin and the root lectins from soybean seedlings immunoelectrophoretically. Soybean seed and root lectins interacted with Rhizobium japonicum and Bradyrhizobium japonicum, but didn't interacted with Rhizobium. viceae, whereas pea lectin conjugated with R. viceae, but didn't bind with R. japonicum and B. japonicum. Lipopolysaccharides of B. japonicum and R. viceae were fractionated into LPS I and LPS II on the sephadox G-50. Lipopolysaccharides from B. japonicum showed rhe binding acitivity both with soybean seed lectin and root lectin, but those from R. viceae didn't show it with soybean seed and root lectins.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.288-294
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• 1997

In order to obtain a basic information related to the utility of Sinorhizobium fredii for field soybean, the effectiveness and competitiveness of nine fast-growing S. fredii strains including TAL 1871 etc. were examined on eleven Korean soybean(Glycin max L.) cultivars. Nine S. fredii strains all modulated soybean cv. Kwangkyo, but did not Danyeobkong. The averaged shoot dry weight by S. fredii strain TAL 1781, TAL 1840, TAL 1899 marked only about 53% as compared to that by Bradyrhizobium japonicum strain YCK 213 and USDA 110. The shoot dry weight by S. fredii strains, of which TAL 1781 was the most effective in that, was increased by coinoculation with B. japonicum YCK 213 rather than with B. japonicum USDA 110. Nodule occupancy by S. fredii ranged from 8.3 to 26.7% in coinoculation with B. japonicum YCK 213, but did from 10.0 to 30.0% with B. japonicum USDA 110. These results indicated that S. fredii strains were inferior effective and competitive to B. japonicum strains.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.60-66
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• 1996

Bradyrhizobium japonicum with different colony morphology populated in five Yeongnam soils of Korea was examined for intrinsic antibiotic resistance to eight antibiotics, serological property by immunoblot and immunodiffusion, and protein profile differentiation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Colony morphological distribution of one hundred and twenty B. japonicum isolates was 47% for "dry". 41% for "wet", and 12% for "dry/wet" type. The total isolates showed such a strong correlation between the morphology and antibiotic resistance. Colony morphology, which though was dominantly consisted of the same type within a serogroup, wasn't absolutely linked to serological property of B. japonicum. Based on these data, colony morphology was too simple to identify variations with B. japonicum isolates : antibiotic resistance such complicated compared with serological analyses.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.267-272
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• 2000

A 1.7-kb fragment containing the nodD1 genes of Bradyrhizobium sp. (Cassia) CN9135 was amplified by PCR with primers based on B. japonicum USDA110. This fragment was cloned and sequenced. Analysis of the sequence showed open reading frames highly homologous to nodD1 from other bradyrhizobial sources. The sequence showed higher homology to nodD1 gene of B. elkanii than to those from b. japonicum. Our results suggest that Bradyrhizobium sp. (Cassia) CN9135 may be more closely related to B. elkanii than to B. japonicum.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.351-357
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• 1996

콩으로부터 분리한 140균주의 근류균은 25균주(17.9%)가 Rhizobium fredii로 115 균주(82.1%)가 Brady-rhizobium japonicum으로 동정되었다. R. fredii에 속하는 분리 균주의 생존 pH 범위는 4..5∼9.0이었고 B. japonicum의 생육 pH 범위는 5.5∼8.0로 비교적 좁게 나타났다. B. japonicum에 속하는 98균주 중에서는 53균주(54%)가 IAA를 생산하지 않는 GT I group으로, 45균주(46%)는 IAA를 생산하는 GT II group으로 명확하게 구분되었으며, 항생물질에 대한 내성 유무에 의해 10개의 group으로 구분되었다.

• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.241-243
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• 1995

A lipopolysaccharide (LPS) defective mutant of Bradyrhizobium japonicum was characterized in terms of its cell surface hydrophobicity (CSH). By monitoring the kinetics of adhesion to hexadecane the LPS mutant was found to be far more hydrophobic than the wild type strain; the removal coefficients were 4.65 $min^{-1}$ for the mutant, as compared with only 2.40 $min^{-1}$ for the wild type. The possible role of cell surface hydrophobicity of B. japonicum in nodulation process is discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.265-267
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• 2005

Study on effectiveness of Bradyrhizobium japonicum on soybean [Glycine max (L.) Merr.], local cultivar 'Sathiya' were carried out in the garden soil of Trib-huvan University. Different parameters like nodulation, chlorophyll content in fresh leaves and growth of plant in inoculated and uninoculated plant was studied. Pot experiment was conducted in the green house to evaluate the effectiveness of B. japonicum on soybean. It was observed that B. japonicum inoculation increased the number of nodules, shoot length of plant and total chlorophyll content in fresh leaves of soybean plant. However, root length was decreased in all inoculated plants.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.62-67
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• 1999

As a basic experiment to enhance the symbiotic utility of atmospheric nitrogen on soybean, host affinities and serological distribution of Bradyrhizobium japonicum indigenous to five Korean upland soils were measured. Based on nodulation, the symbiotic affinities between indigenous B, japonicum and eight soybean cultivars were remarkably different among soil inocula. On the whole, the averaged affinities of B. japonicum populations to soybeans were favorable in order of Goseong > Milyang > Suweon soils, but those in Iksan and Namjeju soils were not, especially for Danweonkong, Jangkyeongkong, and Eunhakong soybean cultivars. Regression analyses between nodules mass and shoot dry weight of soybean yielded model with $R^2=0.51$ for Goseong, $R^2=0.45$ for Milyang, $R^2=0.38$ for Iksan, $R^2=0.28$ for Namjeju, and $R^2=0.24$ for Suweon soils. B. japonicum from sampled soils were serologically fell into more than seven serogroups such as YCK 117(34.1%), YCK 141(6.5%), YCK 321(6.5%), YCK 445(4.7%), YCK 338(2.9%), YCK 150(1.2%), YCK 258(0.6%). The dominant serogroup YCK 117 was distributed 51.9 for Namjeju, 45.8 for Goseong, 41.7 for Iksan. 34.2 for Sueveon, and 11.1% for Milyang soils.