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Characteristics of Indigenous Rhizobium to Korean Soils -I. Symbiotic Potentials of Bradyrhizobium japonicum Populations and Their Colony Morphological Characteristics in Yeongnam Soils (우리나라 토착근류균(土着根瘤菌)의 제(諸) 특성(特性) 연구(硏究) -I. 영남지역(嶺南地域) 토착(土着) 대두근류균(大豆根瘤菌)의 접종효과(接種效果)와 취락형태적(聚落形態的) 분포특성(分布特性))

  • Kang, Ui-Gum;Somasegaran, Padma;Jung, Yeun-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • v.23 no.1
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    • pp.60-66
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    • 1990
  • Soybean [Glycin max (L.)] cv. Jangbaekkong was inoculated with 5 cultivated- and 5 uncultivated upland soils, in Yeongnam area, as soil inoculum and NifTAL peat inoculum as standard for soil inoculum potentials by Bradyrhizobium japonicum. 120 Bradyrhizobium japonicum isolates out of the soil populations were scored of three colony morphologies, designed "Dry", "Wet", and "Dry/Wet", and symbiotic effectiveness between "Dry" and "Wet" was compared. The results obtained were summarized as follows: 1. Indigenous populations of B. japonicum were above $10^4cells/g$. soil at the cultivated upland soils but were a few at the uncultivated upland soils except a colluvivum, orchard previously, in Yeongnam area. 2. Inoculum potentials of the cultivated upland soils were higher than the NifTAL inoculum and generally, nodule mass compensated nodule number for symbiotic effectiveness of soil populations. 3. Colony morphologies of soil populations showed the different proportions of "Dry" and "Wet" so that "Dry" types were dominant at the cultivated upland soils while "Wet" types at the uncultivated upland soils. 4. "Dry" colony morphology significantly exhibited higher symbiotic effectiveness than "Wet" types in nodule fresh weight, shoot dry weight, and shoot dry weight/nodule fresh weight. Therefore, as long as soil inoculum potentials, the growth of soybean at the cultivated upland soils could presumedly be affected by soil populations of Bradyrhizobium japonicum of "Dry" colony morphology.

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Polyphasic Analysis of the Bacterial Community in the Rhizosphere and Roots of Cyperus rotundus L. Grown in a Petroleum-Contaminated Soil

  • Jurelevicius, Diogo;Korenblum, Elisa;Casella, Renata;Vital, Ronalt Leite;Seldin, Lucy
    • Journal of Microbiology and Biotechnology
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    • v.20 no.5
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    • pp.862-870
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    • 2010
  • Cyperus rotundus L. is a perennial herb that was found to be dominating an area in northeast Brazil previously contaminated with petroleum. In order to increase our knowledge of microorganism-plant interactions in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analysis based on the 16S rRNA gene showed that the bacterial community in bulk soil, rhizosphere, and root samples had a high degree of similarity. A complex population of alkane-utilizing bacteria and a variable nitrogen-fixing population were observed via PCR-DGGE analysis of alkB and nifH genes, respectively. In addition, two clone libraries were generated from alkB fragments obtained by PCR of bulk and rhizosphere soil DNA samples. Statistical analyses of these libraries showed that the compositions of their respective populations were different in terms of alkB gene sequences. Using culturedependent techniques, 209 bacterial strains were isolated from the rhizosphere and rhizoplane/roots of C. rotundus. Dot-blot analysis showed that 17 strains contained both alkB and nifH gene sequences. Partial 16S rRNA gene sequencing revealed that these strains are affiliated with the genera Bosea, Cupriavidus, Enterobacter, Gordonia, Mycoplana, Pandoraea, Pseudomonas, Rhizobium, and Rhodococcus. These isolates can be considered to have great potential for the phytoremediation of soil with C. rotundus in this tropical soil area.

Mechanism of Metronidazole Resistance Regulated by the fdxA Gene in Helicobacter pylori. (헬리코박터 파일로리에서 fdxA 유전자에 의한 메트로니다졸 내성 조절 기전 연구)

  • Nam, Won-Hee;Lee, Sun-Mi;Kim, Eun-Sil;Kim, Jin-Ho;Jeong, Jin-Yong
    • Journal of Life Science
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    • v.17 no.5 s.85
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    • pp.723-727
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    • 2007
  • Resistance to metronidazole in Helicobacter pylori results from inactivation of rdxA and frxA, the chromosomal genes for a nitroreductase that normally converts metronidazole from prodrug to bactericidal agent. Two types of metronidazole susceptible strains had been found distinguishable by their apparent levels of frxA expression. Most common in the populations we had studied were strains that required only rdxA inactivation to become resistant to moderate levels of metronidazole(type I strains). The second strain type required inactivation of both frxA and rdxA to become resistance to metronidazole(type II strains): this was linked to a relatively high level of frxA gene transcription in the type II strains. The fdxA gene regulated fdxA as well as rdxA gene. Thus, to study the function of fdxA as a regulatory gene we constructed a null mutant of fdxA in H. pylori genome and identified over-and under-expressed proteins by fdxA using two-dimensional(2-D) electrophoresis and MALDI-TOP-MS. There were four over-expressed proteins in fdxA mutant; nifU-like protein(HP0221), frxA(HP0642), nonheme ferritin(HP0653), and hypothetical protein(HP0902). Three under-expressed proteins were also identified in fdxA mutant, including 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (HP0089), (3R)-hydroxymyristoyl ACP dehydratase(HP1376), and thioredoxin(HP1458).

Diversity of Root-Associated Paenibacillus spp. in Winter Crops from the Southern Part of Korea

  • CHEONG HOON;PARK SOO-YOUNG;RYU CHOONG-MIN;KIM JIHYUN F.;PARK SEUNG-HWAN;PARK CHANG SEUK
    • Journal of Microbiology and Biotechnology
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    • v.15 no.6
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    • pp.1286-1298
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    • 2005
  • The genus Paenibacillus is a new group of bacilli separated from the genus Bacillus, and most of species have been isolated from soil. In the present study, we collected 450 spore-forming bacilli from the roots of winter crops, such as barley, wheat, onion, green onion, and Chinese cabbage, which were cultivated in the southern part of Korea. Among these 450 isolates, 104 Paenibacillus-like isolates were selected, based on their colony shape, odor, color, and endospore morphology, and 41 isolates were then finally identified as Paenibacillus spp. by 16S rDNA sequencing. Among the 41 Paenibacillus isolates, 23 were classified as P. polymyxa, a type species of the genus Paenibacillus, based on comparison of the 16S rDNA sequences with those of 32 type strains of the genus Paenibacillus from the GenBank database. Thirty-five isolates among the 41 Paenibacillus isolates exhibited antagonistic activity towards plant fungal and bacterial pathogens, whereas 24 isolates had a significant growth-enhancing effect on cucumber seedlings, when applied to the seeds. An assessment of the root-colonization capacity under gnotobiotic conditions revealed that all 41 isolates were able to colonize cucumber roots without any significant difference. Twenty-one of the Paenibacillus isolates were shown to contain the nifH gene, which is an indicator of $N_{2}$ fixation. However, the other 20 isolates, including the reference strain E681, did not incorporate the nifH gene. To investigate the diversity of the isolates, a BOX-PCR was performed, and the resulting electrophoresis patterns allowed the 41 Paenibacillus isolates to be divided into three groups (Groups A, B, and C). One group included Paenibacillus strains isolated mainly from barley or wheat, whereas the other two groups contained strains isolated from diverse plant samples. Accordingly, the present results showed that the Paenibacillus isolates collected from the rhizosphere of winter crops were diverse in their biological and genetic characteristics, and they are good candidates for further application studies.

Isolation and Characterization of Endophytic Bacteria from Rice Root Cultivated in Korea (한반도 중부지방의 벼 뿌리로부터 내생 세균의 분리와 특성 분석)

  • Park, Soo-Young;Yang, Sung-Hyun;Choi, Soo-Keun;Kim, Ji-Hyeon;Kim, Jong-Guk;Park, Seung-Hwan
    • Microbiology and Biotechnology Letters
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    • v.35 no.1
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    • pp.1-10
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    • 2007
  • The 44 endophytic bacterial strains were isolated from surface-sterilized root of rice cultivated in seven different locations of Chungcheong province, Korea. Each isolate was introduced into rice seedlings grown gnotobiotically by inoculating scissor-cut first true leaf with cell suspensions, and the colonization capacity of each isolate in root tissue was analyzed at 7 days after inoculation. Sixteen out of 44 isolates were re-isolated from root successfully with the frequency of $10^{3-5}$ CFU/g tissue. Interestingly, seven out of 16 isolates were identified as Burkholderia species. The identity between inoculated strains and re-isolates was confirmed by genomic finger-printing and 16S rDNA sequence analysis. By a confocal laser scanning microscopic observation it was revealed that KJ001 strain, one of the sixteen isolates tagged with gfp colonized in root tissue especially around xylem. Six out of seven Burkholderia strains obtained in this study showed antagonizing activities against seven different fungal pathogens, contain nifH gene, and five of them enhanced growth of cucumber over 30%. The isolates showed no hypersensitive response on tobacco leaves and no pathogenecity in rice. From these results it was found that the endophytic Burkholderia strains will be useful in agriculture to develop a biocontrol agent or a bio-fertilizer.

Two-Dimensional Electrophoresis Analysis of Proteins between Bacillus licheniformis DM3 and Its Antifungal Activity Deficient Mutant (이차원전기영동법을 이용한 길항세균 Bacillus licheniformis DM3와 이의 항진균 활성 결여 돌연변이균주간 단백질 비교 분석)

  • Lee, Young-Keun;Kim, Jae-Sung;Chung, Hye-Young;Jang, Yu-Sin;Jang, Byung-Il
    • Korean Journal of Environmental Agriculture
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    • v.22 no.3
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    • pp.203-209
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    • 2003
  • In the course of screening for antifungal agents, a bacterial strain, DM3 was isolated from a mud sample collected at Daechon in Chungnam province and identified as Bacillus licheniformis based on API 50CHB test. It has antifungal activity against 12 plant pathogenic fungi in paper disc assay. At the 95% lethal dose of gamma radiation ($^{60}Co$, 10 kGy, $D_{10}=2.32\;kGy$), the antifungal activity deficient mutant (mDM3) against Colletotrichum gloeosporioides was induced From 2-D electrophoresis analysis, serine hydroxymethyltransferase (45.0 kDa), hypothetical protein(40.7 kDa), NifU protein homolog(15.4 kDa), and resolvase(12.5 kDa) homologous proteins were detected only in B. licheniformis DM3. Lysozyme(18.1 kDa) and alkyl hydroperoxide reductase(15.6 kDa) homologous proteins were expressed uniquely in B. licheniformis mDM3. Further studies are needed to reveal that these proteins from B. licheniformis DM3 could be closely related to the antifungal activity against plant pathogenic fungi.

Characteristics of Indigenous Rhizobium to Korean Soils -II. Symbiotic and Serological Characteristics of Bradyrhizobium japonicum Naturalized in Yeongnam Soils (우리나라 토착근류균(土着根瘤菌)의 제(諸) 특성(特性) 연구 -II. 영남지역(嶺南地域) 토착(土着) Bradyrhizobium japonicum의 공생(共生) 및 혈청학적(血淸學的) 특성(特性))

  • Kang, Ui-Gum;Jung, Yeun-Tae;Somasegaran, Padma;Hoben, H.;Bohlool, B. Ben
    • Korean Journal of Soil Science and Fertilizer
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    • v.24 no.1
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    • pp.61-68
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    • 1991
  • Thirty Bradyrhizobium japonicum isolates (10 strains per each soil) from 1 uncultivated [Sangnam(Soil 1), Milyang]- and 2 cultivated [Dong(Soil 2)and Chinbuk(Soil 3), Changweon] upland soils in Yeongnam area were evaluated on their symbiotic effectiveness to soybean [Glycin max (L.)] cv. Korean Jangbaekkong and American Clark and examined on their serological diversity. The results obtained were summarized as follows : 1. On symbiotic effectiveness of B. japonicum with plant genotypes, isolates showed a relatively high value of nodule mass in Jangbaekkong cv. and of shoot dry weight and total nitrogen in Clark cv. demonstrating the order of Soil 1> Soil 2> Soil 3 isolates. 2. Among 30 B. japonicum isolates, YCK 141 showed the best effectiveness on mean nitrogen fixation of two cultivars. 3. Thirty indigenous B. japonicum showed 6 types of serological diversities in the immunoblot analysis which were present in various proportions at Soil 2(5) and Soil 3(5) except Soil 1 where all isolates fell into the YCK 117 serogroup. And their distribution order was serotype YCK 117( 12 strains) > USDA 1l0(5strains), USDA 123(5 strains) > YCK 150(4 strains) > YCK 141(3 strains) > YCK 226(1 strain). 4. Especially, 10 isolates from Soil 1, an uncultivated orchard, showed a very homologous pattern in not only effectiveness but serological distribution. It seemed to indicate that the isolates were typically affected by numerous physical and environmental factors of the soil.

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The Impact of Capital Adequacy and Operating Efficiency on Saudi Banks Performance

  • Khaled Subhi, RAJHA
    • The Journal of Asian Finance, Economics and Business
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    • v.10 no.2
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    • pp.333-341
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    • 2023
  • This study investigates the impact of capital adequacy and operating efficiency on the performance of Saudi banks. In the first part, the study includes a brief introduction focused on the impact of capital adequacy and operating efficiency on the performance of banks. In the second part, a literature review examined various studies on the impact of capital adequacy and operating efficiency on banks' performance. The study methodology was presented in the third part, based on a sample that included all local Saudi banks from 2010 to 2021, using a study model to answer the study hypotheses. The results of the panel data regression indicated that CAR had a negative and significant effect on ROA and ROE but a negative and non-significant effect on NIM. CIR has a negative and significant effect on ROA, ROE, and NIM, while SIZE, LTD, and MS have a positive and significant effect on ROA, ROE, and NIM. Elimination of defects has no significant effect on return on assets, return on equity, and the NIF. But CR has no significant effect on ROA and ROE but has a positive and significant effect on NIM.