• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.955-959
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• 2003

Rhizobium tropici CIAT 899 is capable of synthesizing inactive apo-glucose dehydrogenase (GDH). To become an active holo enzyme, the GDH requires a cofactor, PQQ. When R. tropici CIAT 899 was grown in a broth culture medium containing hydroxyapatite and pyrrolo quinoline quinone (PQQ), pH decreased while the concentration of soluble P increased. The solubilization of hydroxyapatite was associated with the production of gluconic acid and 2-ketogluconic acids. The organic acid production and P solubilization were greatly enhanced when the bacterium was grown with air supply. Effect of R. tropici CIAT 899 with (CI＋PQQ) and without PQQ (CI) on the common bean growth was examined. Shoot and root weight, and N and P contents in CI＋PQQ treatment, were significantly higher than those in control and CI treatment. Nodule weight and acetylene reducing activities were also significantly higher in CI＋PQQ treatment than in other treatments.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.498-502
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• 2004

The current study was conducted to monitor the possibility of the gene transfer among soil bacteria, including the effect of drift due to rain and surface water, in relation to the release of genetically modified organisms into the environment. Four types of bacteria, each with a distinct antibiotic marker, kanamycin-resistant P. fluorescens, rifampicin-resistant P. putida, chloramphenicol-resistant B. subtilis, and spectinomycin-resistant B. subtilis, were plated using a small-scale soil-core device designed to track drifting microorganisms. After three weeks of culture in the device, no Pseudomonas colonies resistant to both kanamycin and rifampicin were found. Likewise, no Bacillus colonies resistant to both chloramphenicol and spectinomycin were found. The gene transfer from glyphosate-tolerant soybeans to soil bacteria, including Rhizobium spp. as a symbiotic bacteria, was examined by hybridization using the DNA extracted from soil taken from pots, in which glyphosate-tolerant soybeans had been growing for 6 months. The results showed that 35S, T-nos, and EPSPS were observed in the positive control, but not in the DNA extracted from the soilborne microorganisms. In addition, no transgenes, such as the 35S promoter, T-nos, and EPSPS introduced into the GMO soybeans were detected in soilborne bacteria, Rhizobium leguminosarum, thereby strongly rejecting the possibility of gene transfer from the GMO soybeans to the bacterium.

• Applied Biological Chemistry
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• 제29권2호
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• pp.175-181
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• 1986

연속적으로 대두를 재배한 토양과 신개간지 토양에서 재배한 대두 품종 단엽의 근류로부터 토착대두 근류근 87종을 분리하고 이들을 생장속도에 따라 Bradyrhizobium japonicum (slow-grower) 및 Rhizobium fredii (fast-grower)로 분류한 결과 전자가 55종, 후자가 32종이었다. 이두그룹의 대두 근류균을 질산염 환원특성에 따라 denitrifying fast-grower(F-1), nitrate respiring fast-grower(F-II), denitrifying slow-grower(S-I), 및 nitrate respiring slow-grower (S-II)로 세분 되었으며, 분리균주 총 87종중 S-I, S-II, F-I 및 F-II의 수는 각각 10, 22, 48 및 7종이었다. 이들 각 group 대두 근류균의 균체단백질의 전기영동 pattern상의의 차이를 1차 및 2차원 전기영동으로 분석한 결과 slow 및 fast-grower간에는 현저한 차이를 관찰할 수 있었으나 동일 생장속도를 가진 것 중 denitrifer와 nitrate repirer간에는 큰 차이가 없었다.

• Current Research on Agriculture and Life Sciences
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• 제15권
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• pp.25-32
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• 1997

근류균과 두과작물의 공생에서 숙주결합성을 조사하기 위하여 대두 종자 및 및 유근으로부터 분리한 lectin과 근류균의 표피다당과의 결합성을 확인한 결과는 다음과 같다. 팔달, 백운 및 황금으로부터 분리한 종자선을 형성하였다. 대두 종자 lectin 및 뿌리추출물은 R. japonicum및 B. japonicum과 결합하였고 R. viceae와는 결합 하지 않았으며 완두의 lectin은 R. viceae와 결합하였으나 R. japonicum및 B. japonicum과는 결합 하지 않았다. B. japonicum과 R. viceae로 부터 분리한 세포표피 다당의 겔 여과한 결과 두개의 분획으로 각각 나타났다. B. japonicum으로 부터 분리한 표피다당은 대두의 종자 lectin과 결합하였으나 R. viceae로 부터 분리한 표피다당은 대두 lectin과 결합하지 않았다. 이상의 결과로 부터 근류균이 숙주세포와 결합할 때 숙주를 인식하는 초기 단계에서 lectin이 관여함을 추론할 수 있고 이것이 상호접종군을 형성하는데 매개역할을 하는 것으로 추정할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1617-1626
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• 2013

The Bacterial community structure and its complexity of the enrichment culture during the isolation and screening of imidacloprid-degrading strain were studied using denaturating gradient gel electrophoresis analysis. The dominant bacteria in the original tea rhizosphere soil were uncultured bacteria, Rhizobium sp., Sinorhizobium, Ochrobactrum sp., Alcaligenes, Bacillus sp., Bacterium, Klebsiella sp., and Ensifer adhaerens. The bacterial community structure was altered extensively and its complexity reduced during the enrichment process, and four culturable bacteria, Ochrobactrum sp., Rhizobium sp., Geobacillus stearothermophilus, and Alcaligenes faecalis, remained in the final enrichment. Only one indigenous strain, BCL-1, with imidacloprid-degrading potential, was isolated from the sixth enrichment culture. This isolate was a gram-negative rod-shaped bacterium and identified as the genus Ochrobactrum based on its morphological, physiological, and biochemical properties and its 16S rRNA gene sequence. The degradation test showed that approximately 67.67% of the imidacloprid (50 mg/l) was degraded within 48 h by strain BCL-1. The optimum conditions for degradation were a pH of 8 and $30^{\circ}C$. The simulation of imidacloprid bioremediation by strain BCL-1 in soil demonstrated that the best performance in situ (tea soil) resulted in the degradation of 92.44% of the imidacloprid (100 mg/g) within 20 days, which was better than those observed in the ex situ simulations that were 64.66% (cabbage soil), 41.15% (potato soil), and 54.15% (tomato soil).

• The Plant Pathology Journal
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• 제32권4호
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• pp.347-356
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• 2016

Plants protect themselves from pathogen attacks via several mechanisms, including hypersensitive cell death. Recognition of pathogen attack by the plant resistance gene triggers expression of carboxylesterase genes associated with hypersensitive response. We identified six transcripts of carboxylesterase genes, Vitis flexuosa carboxylesterase 5585 (VfCXE5585), Vf-CXE12827, VfCXE13132, VfCXE17159, VfCXE18231, and VfCXE47674, which showed different expression patterns upon transcriptome analysis of V. flexuosa inoculated with Elsinoe ampelina. The lengths of genes ranged from 1,098 to 1,629 bp, and their encoded proteins consisted of 309 to 335 amino acids. The predicted amino acid sequences showed hydrolase like domains in all six transcripts and contained two conserved motifs, GXSXG of serine hydrolase characteristics and HGGGF related to the carboxylesterase family. The deduced amino acid sequence also contained a potential catalytic triad consisted of serine, aspartic acid and histidine. Of the six transcripts, Vf-CXE12827 showed upregulated expression against E. ampelina at all time points. Three genes (VfCXE5585, VfCXE12827, and VfCXE13132) showed upregulation, while others (VfCXE17159, VfCXE18231, and VfCXE47674) were down regulated in grapevines infected with Botrytis cinerea. All transcripts showed upregulated expression against Rhizobium vitis at early and later time points except VfCXE12827, and were downregulated for up to 48 hours post inoculation (hpi) after upregulation at 1 hpi in response to R. vitis infection. All tested genes showed high and differential expression in response to pathogens, indicating that they all may play a role in defense pathways during pathogen infection in grapevines.

• 한국작물학회지
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• 제34권1호
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• pp.86-91
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• 1989

콩포장에 사용하는 제초제가 근류균의 생존률에 미치는 영향을 구명하기 위하여 제초제 Alachlor, Linuron, Simazine 및 Paraquat를 농도별로 YEMA 배지에 혼합하여 근류균을 접종, 배양하여 생존률을 조사하였다. 1. 콩근류균은 Alachlor와 Linuron의 사용권장 농도인 400ppm 처리에서도 각각 27.4％와 57.8％의 생존률을 보여 유의한 근류균의 감소를 보였다. 2. Simazine은 공시제포제중에서 가장 영향이 적었으며 Paraquat는 200ppm에서도 현저한 생존균수의 감소를 보였다. 3. Alachlor에 대한 근류균의 감수성은 균주에 따라 차이가 있었으며 I-122 균주가 가장 낮은 감수성을, I-145가 가장 높은 감수성을 보였고 중도 저항성인 K-5 균주는 사용권장농도에서는 높은 저항성을 보였으나 농도가 증가함에 따라 급격히 감소하였다. 4. 콩품종의 근류형성력은 균주, 품종에 따라 차이가 있었으며 Alachlor에 저항성인 균주 I-122, K-5 가 높은 근류형성력을 보여 근류형성력은 환경적응력과 밀접한 관계가 있는 것으로 보였다.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1614-1623
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• 2010

Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to $41^{\circ}C$ and at pH 11.

• Applied Biological Chemistry
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• 제28권3호
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• pp.149-155
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• 1985

전국(全國) 223개(個) 지역(地域)에서 수집(蒐集)한 두과작물(豆科作物)의 근류(根瘤)에서 총(總) 590주(株)의 근류균(根瘤菌)을 분리(分離)하여 숙주특이성(宿主特異性)에 따라, R. japonicum 218종(種), R. phaseoli 101종(種), R. trifolii 97종(種), R. meliloti 4종(種), R. leguminosarum 1종(種), Rhizobium species 101종(種), 미분류(未分類)된 균주(菌株) 159종(種)으로 분류(分類)하였다. 분리(分離)된 R. japonicum 218종(種)의 근류형성능(根瘤形成能)과 질소고정능(窒素固定能)을 비교(比較)하여. R. japonicum R-138, R-168, R-214 균주(菌株)를 우수균주(優秀菌株)로 하였다. 분리(分離) 선발(選拔)된 R. japonicum 중(中) 질소고정능(窒素固定能)이 우수(優秀)한 균주(菌株)의 plasmid를 확인(確認)한 결과(結果), fast-growing group 균주(菌株)들은 $1{\sim}4$개(個)의 거대(巨大) plasmid를 함유(含有)하고 있었으며 그 분자량(分子量)은 약(約) $35{\sim}300{\;}Md$ 정도(程度)이었다. 반면 대부분(大部分)의 slow-growing group 균주(菌株)들은 plasmid가 검출(檢出)되지 않았다.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.394-399
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• 1994

The catalytic mechanism of malonyl-CoA synthetase from Rhizobium trifolii was investigated by the steady state kinetics and intermediate identification. Initial velocity studies and the product inhibition studies with AMP and PPi strongly suggested ordered Bi Uni Uni Bi Ping-Pong Ter Ter system as the most probable steady state kinetic mechanism of malonyl-CoA synthetase. Michaelis constants were $0.17{\pm}0.04 {\mu}M,\;0.24{\pm}0.18 {\mu}M\;and\;0.045{\pm}0.26 {\mu}$M for ATP, malonate and CoA, respectively. The TLC analysis of the $^{32}P-labelled$ products in reaction mixture containing $[{\gamma}-^{32}P]$ ATP in the absence of CoA showed that PPi was produced after the sequential addition of ATP and malonate. Formation of malonyl-AMP, suggested as an intermediate in the kinetically deduced mechanism, was confirmed by the analysis of $^{31}P-NMR$ spectra of AMP product isolated from the $^{18}O$ transfer experiment using $[^{18}O]$malonate. Two resonances were observed, corresponding to AMP labelled with zero and one atom of $^{18}O$, indicating that one atom of $^{18}O$ transferred from $[^{18}O]$malonate to AMP through the formation of malonyl-AMP. Formation of malonyl-AMP was also confirmed through the TLC analysis of reaction mixture containing $[{\alpha}-^{32}P]$ATP. These results strongly support the ordered Bi Uni Uni Bi Ping-Pong Ter Ter mechanism deduced from the initial velocity and product inhibition studies.