• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.154-160
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• 2000

Aflatoxin B1 is known as the most potent mycotoxin produced by several fungi. It has been demonstrated to be not only carcinogenic but teratogenic and mutagenic as well in humans. To prevent or inactivate aflatoxins, several chemical of physical methods were tested for ammoniation, using insecticides as an wxample, but they were unsuitable for food products. On the contrary, biological control by antagonistic microorgani는 is and ideal method. In order to control aflatoxin B1 biologically, the antagonists #07, #63, #75, #74, and #61 were separated from various samples by using the antagonistic activity test. Among them, culture filtrate part A (non heat-treated) of #63 and #74 on aflatoxin B1 produced by Aspergillus fkavus were shown to be 95% and 75%, respectively. Based on the morphological characteristics, #63 was deduced as an Azospirillum sp.

• 한국생태학회:학술대회논문집
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• 한국생태학회 2002년도 VIII 세계생태학대회
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• pp.93-100
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• 2002

Dynamics of certain $N_2$fixing bacteria such as Rhizobium, Azospirillum and Azotobactor, nodule number in dominant legume, Atylosia trinervia, P-solubilizing bacteria, actinomycetes and fungi were studied in unburned and burned site of natural grassland, southern India. Population of $N_2$- fixing bacteria, P-solubilizing bacteria, fungi and nodule number in legume increased significantly in burned sites. On the other hand, the actinomycetes population remained unchanged. Thirty six species of fungi with tricalcium phosphate solubilizing ability were recorded. The most efficient P-solubilizing fungi recognised in the soils of the study sites are Absidia ramosa, Gongronella butlerii, Mortieralla spinosa, Mucor racemosus, Rhizopus nigricans, R. stolonifer, R. oryzae, Aspergillus fumigatus, A. nidulans, A. niger Theilavia terricola and Cheatomium lunasporium.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.48-55
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• 2004

Six strains of an obligate predatory bdellovibrio isolate that preys on Burkholderia glumae in rice paddy field water and rhizosphere soil, were identified and characterized. The numbers of Bdellovibrio cells varied from $3.2{\times}10^3$ to $9.2{\times}10^3$ plaque-forming unit/g after enrichment in cells of B. glumae. Prey range tests with six Bdellovibrio strains and 17 prey strains of rice-pathogenic, antibiosis-related, or nitrogen-fixing bacteria resulted in unique predation patterns in related prey cells. Strain BG282 had the widest prey range on 7 plant pathogenic bacteria among the 17 prey strains tested. However, no predation occurred with strains of Azospirillum brasilense, Paenibacillus polymyxa, Pseudomonas fluorescens, P. putida, and Serratia marcescens that are associated with antibiosis or nitrogen fixation in the rice ecosystem. Identification was confirmed by the presence of typical bdelloplast in the prey cells of B. glumae and by a PCR assay using B. bacteriovorus-specific primers. Furthermore, 16S rDNA sequencing of the six bdellovibrio strains showed a homology range of 97.2% to 99.2% to the type strain of B. bacteriovorus.

• The Korean Journal of Ecology
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• 제25권4호
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• pp.227-234
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• 2002

Dynamics of certain $N_2$ fixing bacteria such as Rhizobium, Azospirillum and Azotobactor, nodule number in dominant legume, Atylosia trinervia, P-solubilizing bacteria, actinomycetes and fungi were studied in unburned and burned site of natural grassland, southern India. Population of $N_2$ - fixing bacteria, P-solubilizing bacteria, fungi and nodule number in legume increased significantly in burned sites. On the other hand, the actino-mycetes population remained unchanged. Thirty six species of fungi with tricalcium phosphate solubilizing ability were recorded. The most efficient P-solubilizing fungi recognised in the soils of the study sites are Absidia ramosa, Gongronella butlerii, Mortieralla spinosa, Mucor racemosus, Rhizopus nigricans, R. stolonifer, R. oryzae, Aspergillus fumigatus, A. nidulans, A. niger, Theilavia terricola and Cheatomium lunasporium.

• The Plant Pathology Journal
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• 제23권2호
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• pp.90-96
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• 2007

To overcome the problem of the yield reduction due to the viral satellite mediated protection, a culture mix of three nitrogen-fixing bacteria species of the genus Azospirillum (A. brasilienses N040, A. brasilienses SP7, and A. lipoferum MRB16), and one strain of cyanobacteria (Anabena oryzae Fritsch) were utilized as biofertilizer mixture in both greenhouse and field experiments. When protected plants were treated with biofertilizer mixtures, the fruit yield of biofertilized plants increased by 48% and 40% in a greenhouse and field experiment, respectively, compared to untreated plants inoculated with the protective viral strain alone. Polyacrylamide gel electrophoresis (PAGE) analysis of total nucleic acid (TNA) extracts revealed that biofertilization did not affect the accumulation of the viral satellite RNA (CARNA 5) that is required for plant protection against other destructive viral strains of CMV. The yield increment was a good compensation for the yield loss caused by the use of the protective viral strain associated with CARNA 5.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권1호
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• pp.165-169
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• 2009

A field experiment to evaluate the effect of application of different organic manures and inorganic fertilizers on growth, yield and quality of leaf was studied during 2004-05 has showed that, the application of 10 kg each of Azospirillum brasilense and Aspergillus awamori+20% each of recommended N through compost+green manure (Glyricidia maculata)+castor cake+vermicompost+Urea and remaining P and K through fertilizers ($T_{11}$) has recorded significantly higher leaf yield (250 g/ plant and 34.70 tonnes/ha/yr, respectively) with improvement in growth characters as compared to control. Leaf quality status was also improved in terms of N (3.19%), P (1.97%), K (1.28%), total soluble protein (8.39 mg/ml), total soluble sugars (14.40 mg/ml), secondary nutrients viz., Ca (3.00%), Mg (0.60%), S (0.35%) and micronutrients viz., Cu (0.410 ppm), Mn (0.454 ppm) and Zn (0.112 ppm) contents. The mulberry grown with 20 tonnes of compost+300:120:120 Kg of NPK/ha/year through fertilizer ranked second for growth and foliar constituents.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권1호
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• pp.25-36
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• 2020

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from 1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation, rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which in turn affects the cycling of As and Fe in redox transition zones.

• The Korean Journal of Ecology
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• 제21권5_2호
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• pp.575-583
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were assessed to find out the nature of soil ecosystem of Mt. Paektu. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture, organic matter and avaiable phosphate of the soils were 21.6%, 17.3% and 2.48mg/100g, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. The population size of soil bacteria ranged from 2.7 to $202.5{\times}10^5$ CFU/g.dry soil, and the size is somewhat dependent on the content of moisture and oranic matter of the forest soil. A large number of bacteria was able to decompose macromolecules such as starch, elastin and gelatin. While the distribution rate of resistant bacteria to antibiotics was high, that to toxic chemicals was low. This means that the competition between microorgani는 predominate over the interference with artificial behaviour such as spread of pesticides in the surveyed region. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also main constituents of the soil microflroa. any one of the strains was not identified as Azospirillum or Micrococcus which are known to be one of major constituents of the forest soil. for the correct identification of isolates chemotaxonomic studies will be proceeded, and the strains are to be stored in the Type collection Center.

• 한국토양비료학회지
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• 제42권Spc호
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• pp.20-28
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• 2009

생물비료는 아직도 한국에서는 생소한 용어다. 한국에서 생물비료라 함은 식물추출액, 퇴비류-다양한 형태의 미생물 혼합제 등으로 인식되고 있다. 그러나 최근에는 식물영양요소의 흡수나 이용도를 증진시키는 토양미생물 사용으로 언급하기도 한다. 본 개관은 식물성장을 증진시키는 것으로 알려진 PGPR 서로 다른 기작과 실질적 역할에 대하여 검토하였다.

• 한국토양비료학회지
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• 제21권3호
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• pp.307-315
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• 1988

근류균(根瘤菌)과 두과식물(荳科植物)과의 상호공생관계(相互共生關係)에서 발현(發現)되는 생물학적(生物學的) 질소고정(窒素固定)의 효율(效率)을 증진(增進)하기 위한 연계연구(連繫硏究)로 전보(前報)에 이어 콩 품종(品種), 질소기종(窒素期種) 및 시용량(施用量)을 달리한 in situ 숙건에서 대두근류균(大豆根瘤菌)과 협생(協生) 질소고정균(窒素固定菌)와의 상호접종효과(相互接種效果)를 질소고정효율면(窒素固定效率面)에서 검토(檢討)한 결과(結果)는 다음과 같다. 1. 콩 건물수량(乾物收量)은 H-25 및 단엽(短葉)콩 모두 근류균(根瘤菌)과 무접종(無接種)보다 근류균(根瘤菌) 단독(單獨) 및 근류균(根瘤菌)과 협생균(協生菌)과의 혼합접종(混合接種)으로 유의(有意)한 증가효과(增加效果)를 보았으나, 각(各) 균주(菌株)의 접종매체간(接種媒體間)에는 유의(有意)한 차(差)가 없었다. 또한 질소비종(窒素肥種) 및 시용량간(施用量間) 콩 건물수량(乾物收量)은 유안(硫安)보다 질산가리시용(窒酸加里施用)이 유의(有意)한 증가(增加)를 보였으며 질소시용량(窒素施用量) 증가(增加)에 따라 감소(減少)하는 경향(傾向)이었다. 2. 접종(接種) 매체량간(媒體量間) 질소고정력(窒素固定力)은 H-25 품종(品種)에서는 현저(顯著)한 차이(差異)가 없었으나, 단엽(短葉)콩에서는 근류균(根瘤菌)과 협생질소고정균(協生窒素固定菌)과의 혼합접종(混合接種)보다 근류균(根瘤菌) 단독접종시(單獨接種時) 증가(增加)되는 경향(傾向)이었다. 3. 콩 건물수량(乾物收量)과 질소고정관련(窒素固定關聯) 각(各) 요인간(要因間) 상호관계(相互關係)에서 근류형성량(根瘤形成量) 및 TNA(total nitrogenase activity)는 고도(高度)의 유의(有意)한 정(正)의 상관관계(相關關係)를 보였다. 4. 공생(共生) 질소고정효과(窒素固定效果)를 보면, H-25 품종(品種)은 84 AS-1의 근류균(根瘤菌)을 단독접종(單獨接種)하고 유안(硫安)을 54mM시용시(施用時) 149 %로 제일 높았으나 단엽(短葉)콩은 84DY-1를 단독접종(單獨接種)하고 질소가리(窒素加里)를 18mM시용시(施用時) 질소고정효과(窒素固定效果)가 155%로 제일 높았다.