• 한국균학회지
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• 제40권2호
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• pp.118-123
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• 2012

대표적인 감귤 녹색곰팡이병(Penicillium digitatum) 방제용 생물농약을 개발하고자 제주도내 7개 과수원으로부터 채집된 citrus 잎에서 21균주의 내생세균을 분리하였다. 그 중 5개의 세균이 녹색곰팡이병균 P. digitatum에 항균활성을 나타냈으며, 대치배양에서 가장 강력한 항균활성을 보인 CB3 균주가 선발되었다. CB3 균주는 간상형의 그람 양성세균으로 생리 생화학적 특성과 gyrA 유전자 염기서열 분석에 의해 Bacillus velezensis로 동정되었다. CB3 균주는 감귤 저장병 병원균 Penicillium digitatum에 강력한 항균활성을 나타내었다. $1{\times}10^5$ spores/ml에 이르는 고농도의 P. digitatum을 감귤에 상처접종했을 때에도, $1{\times}10^8$ cfu/ml의 CB3에 의한 방제효과는 66.7%로 매우 높았다. 본 연구결과, Bacillus velezensis CB3의 안정성과 강한 방제활성 등을 고려할 때 유용 친환경적 방제제로서 매우 가치가 있을 것으로 판단된다.

• 한국버섯학회지
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• 제22권2호
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• pp.67-72
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• 2024

본 연구에서는 느타리버섯의 생육단계별 미생물 군집을 species수준에서 조사하였다. 살균전 배지에서는 그람 양성균이 우점하였다. 반면 배양완료 배지, 수확 후 배지, 그리고 자실체에서는 그람 음성균이 우점하였다. 미생물의 다양성을 확인한 결과 살균 전 배지가 다른 생육단계에 비해 다양한 미생물을 포함하고 있는 것을 확인하였으며, 배양완료배지, 자실체, 수확 후 배지의 순서로 다양성이 감소하는 경향을 보였다. 미생물의 유사도분석을 한 결과 배양완료배지와 수확 후 배지가 유사한 미생물군집을 보이는 것을 확인하였고, 자실체의 경우 일부 유사성을 보이지만 전반적으로는 차이를 나타내었다. 이러한 결과를 토대로 확인하였을 때 살균과정을 거치지 않은 살균 전 배지에서는 검출되지 않은 Pseudomonas tolaasii가 살균 과정을 거친 배양완료배지, 수확후 배지에서 검출된 것으로 보아 살균 이후 접종 혹은 배양하는 과정에서 미생물이 유입하였을 것으로 추정된다. 또한 유해균이 유입되었지만 병징이 나타나지 않은 것은 유해균을 억제하는 유익균의 존재와 병징을 일으키는 농도보다 낮은 것의 영향으로 추정된다. 앞으로, 유해균이 유입되었지만 병징이 나타나지 않은 원인과 기작에 대한 연구가 필요하다.

• Journal of Microbiology
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• 제45권2호
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• pp.105-112
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• 2007

The objective of this study was to analyze the phylogenetic composition of bacterial community in the soil of an earth-cave (Niu Cave) using a culture-independent molecular approach. 16S rRNA genes were amplified directly from soil DNA with universally conserved and Bacteria-specific rRNA gene primers and cloned. The clone library was screened by restriction fragment length polymorphism (RFLP), and representative rRNA gene sequences were determined. A total of 115 bacterial sequence types were found in 190 analyzed clones. Phylogenetic sequence analyses revealed novel 16S rRNA gene sequence types and a high diversity of putative bacterial community. Members of these bacteria included Proteobacteria (42.6%), Acidobacteria (18.6%), Planctomycetes (9.0 %), Chloroflexi (Green nonsulfur bacteria, 7.5%), Bacteroidetes (2.1%), Gemmatimonadetes (2.7%), Nitrospirae (8.0%), Actinobacteria (High G+C Gram-positive bacteria, 6.4%) and candidate divisions (including the OP3, GN08, and SBR1093, 3.2%). Thirty-five clones were affiliated with bacteria that were related to nitrogen, sulfur, iron or manganese cycles. The comparison of the present data with the data obtained previously from caves based on 16S rRNA gene analysis revealed similarities in the bacterial community components, especially in the high abundance of Proteobacteria and Acidobacteria. Furthermore, this study provided the novel evidence for presence of Gemmatimonadetes, Nitrosomonadales, Oceanospirillales, and Rubrobacterales in a karstic hypogean environment.

• 대한수의학회지
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• 제47권3호
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• pp.315-319
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• 2007

Fibrinopurulent peritonitis and abdominal abscesses associated with Streptococcus (S.) equi subsp. zooepidemicus is reported in a 1-year-old female thoroughbred horse. The horse died after showing 5-day history of the cold, severe abdominal distention, abdominal breathing, hyperthermia, anorexia, and loss of intestinal sound. At necropsy, several liters of turbid yellowish green fluid were seen in the abdominal cavity. Yellowish creamy and fibrinous or bloody materials were presented on the serosa of various abdominal organs that were intensively adhered with each other. Spleen and mesenteric lymph node were remarkably enlarged. Affected lobes of the lung showed severe congestion, hemorrhage and doughy consistency. Histologically, the lung showed hemorrhagic pneumonia with diffuse congestion and edema. Severe diffuse fibrinopurulent peritonitis with Gram-positive bacterial cocci and adjacent fibrosis were showed in the serosa of various abdominal organs such as liver, spleen, stomach, and intestine. And multifocal abscess pouches were presented in the granulation tissue of abdominal viscera. S. equi subsp. zooepidemicus was isolated from the peritoneal swab, abdominal organs, and lung. Hematogenous dissemination of bacteria from hemorrhagic pneumonia is proposed as the route of infection in this case.

• Journal of Microbiology and Biotechnology
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• 제21권10호
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• pp.1073-1080
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• 2011

In order to investigate and generalize the effects of carbon and nitrogen sources on the growth of and lipid production in Chlorella sp. 227, several nutritional combinations consisting of different carbon and nitrogen sources and concentrations were given to the media for cultivation of Chlorella sp. 227, respectively. The growth rate and lipid content were affected largely by concentration rather than by sources. The maximum specific growth was negatively affected by low concentrations of carbon and nitrogen. There is a maximum allowable inorganic carbon concentration (less than 500~1,000 mM bicarbonate) in autotrophic culture, but the maximum lipid content per gram dry cell weight (g DCW) was little affected by the concentration of inorganic carbon within the concentration. The lipid content per g DCW was increased when the microalga was cultured with the addition of glucose and bicarbonate (mixotrophic) at a fixed nitrogen concentration and with the lowest nitrogen concentration (0.2 mM), relatively. Considering that lipid contents per g DCW increased in those conditions, it suggests that a high ratio of carbon to nitrogen in culture media promotes lipid accumulation in the cells. Interestingly, a significant increase of the oleic acid amount to total fatty acids was observed in those conditions. These results showed the possibility to induce lipid production of high quality and content per g DCW by modifying the cultivation conditions.

• 한국토양비료학회지
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• 제49권4호
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• pp.318-326
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• 2016

Two phosphate solubilizing bacteria, Pantoea rodasii PSB-11and Enterobacter aerogenes PSB-12, were isolated from button mushroom compost and employed to assess their synergistic effect in liquid medium and on growth of green gram plants by single and co-inoculation of the strains. Co-inoculation of two strains was found to release the highest content of soluble phosphorus ($521{\mu}g\;ml^{-1}$) into the medium, followed by single inoculation of Pantoea strain ($485{\mu}g\;ml^{-1}$) and Enterobacter strain ($470{\mu}g\;ml^{-1}$). However, there was no significant difference between single inoculation of bacterial strain and co-inoculation of two bacterial strains in terms of phosphorous release. The highest pH reduction, organic acid production and glucose consumption was observed in the E. aerogenes PSB-12 single inoculated culture medium rather than those of co-inoculation. According to the plant growth promotion bioassay, co-inoculated mung bean seedlings recorded 10.6% and 10.7% higher shoot and root growth respectively compared to the control. Therefore, in concluding, co-inoculation of the strains P. rodasii and E. aerogenes displayed better performance in stimulating plant growth than inoculation of each strain alone. However, being short assessment period of the present study, we recommend in engaging further works under field conditions in order to test the suitability of the strains to be used as bio-inoculants.

• KSBB Journal
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• 제27권3호
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• pp.151-156
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• 2012

Lactic acid is an important product arising from the anaerobic fermentation by lactic acid bacteria (LAB). It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. The poly lactic acid (PLA) is an important material for bio-plastic manufacturing process. For PLA production by new LAB, we screened LAB isolates from shellfish. A total of 28 LAB were isolated from various shellfishes. They were all Gram positive, oxidase and catalase negative. Based on API 50CHL kit, 7 strains among the 28 isolates were identified as Lactobacillus plantarum, 6 strains as Lactobacillus delbrueckii, 5 strains as Leuconostoc mesenteroides, 3 strains as Lactobacillus brevis, 2 strains as Lactococcus lactis, 1 strain as Lactobacillus salivarius, 1 strain as Lactobacillus paracasei, 1 strain as Lactobacillus pentosus, 1 strain as Lactobacillus fermentum and 1 strain as Pediococcus pentosaceu. Also, we examined the amount of total lactic acid produced by these new strains by HPLC analysis with Chiralpak MA column. One strain E-3 from Mytilus edulis was indentified as Lactobacillus plantarum and found to produce 20.0 g/L of D-form lactic acid from 20 g/L of dextrose. Further studies are underway to increase the D-lactic acid production by E-3.

• 식물병연구
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• 제16권1호
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• pp.97-100
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• 2010

2009년 진주시 수곡면 딸기 노지재배 육묘 포장과 하동군 옥종면 촉성재배 시설하우스 딸기포장에서 병이 발생하였다. 병징은 잎에 수침상의 작은 반점이 서서히 생기면서 엽맥의 주위에 다각형의 모무늬 병반이 나타나고 노란색의 달무리가 형성하는 것이 특징이다. 병든 잎은 서서히 시들고 암갈색으로 말라 죽는다. YDC 배지 상에서 병원균의 균총은 노란색을 띤 오랜지 색소를 분비하며 둥근 콜로니를 형성하고 단극모를 가지고 있다. 딸기에 접종한 결과 병원성이 잘 나타났다. 이상과 같이 딸기에 발생한 병정, 병원균의 특징 및 병원성을 검정한 결과 Xanthomonas fragariae에 의한 딸기 세균성모무늬병으로 동정하였다.

• 한국축산식품학회지
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• 제31권6호
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• pp.851-857
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• 2011

This study was conducted to develop a real time reverse transcriptase-PCR (RT-PCR) method for the detection of viable Enterobacteriaceae in milk using primers based on the genes of ribosomal proteins S11 and S13 and to determine effects of heating and subsequent treatments on the threshold cycle (Ct) of the real time RT-PCR. Total RNA was isolated from 17 strains of bacteria including 11 strains of Enterobacteriaceae suspended in milk using a modified Tri reagent method. SYBR Green Master Mix was added to the RNA and the mixture was subjected to the real time RT-PCR. The Cts of eleven type strains of the Enterobacteriaceae in milk ($10^7$ cells) in the real time RT-PCR ranged from 21.5 to 24.6. However, the Cts of Pseudomonas fluorescens, Acinetobacter calcoaceticus, and three gram-positive bacteria were more than 40. The real time RT-PCR detected as low as $10^3$ cells in agarose gel electrophoresis. The Cts increased from 22.0 to 34.2 when milk samples contaminated with Escherichia coli ($10^7$ cells/mL) were heated at $65^{\circ}C$ for 30 min. In addition, subsequent incubation at $37^{\circ}C$ for 6 and 24 h increased the Cts further up to 36.2 and 37.2, respectively. Addition of RNase A to the bacterial suspension obtained from the heated milk and subsequent incubation at $37^{\circ}C$ for 1 h increased the Cts to more than 40. The results of this study suggests that pretreatment of bacterial cells heated in milk with RNase A before RNA extraction might enhance the ability to differentiate between viable and dead bacteria using real time RT-PCR.

• 농업과학연구
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• 제43권3호
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• pp.401-414
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• 2016

The synergistic effect on phosphate solubilization of single- and co-inoculation of two phosphate solubilizing bacteria, Burkholderia anthina PSB-15 and Enterobacter aerogenes PSB-16, was assessed in liquid medium and green gram plants. Co-inoculation of two strains was found to release the highest content of soluble phosphorus ($519{\mu}g\;mL^{-1}$) into the medium, followed by single inoculation of Burkholderia strain ($492{\mu}g\;mL^{-1}$) and Enterobacter strain ($483{\mu}g\;mL^{-1}$). However, there was no significant difference between single inoculation of bacterial strain and co-inoculation of two bacterial strains in terms of phosphorous release. The highest pH reduction, organic acid production, and glucose consumption were observed in the culture medium co-inoculated with PSB-15 and PSB-16 strains rather than that of single inoculation. Based on the plant growth promotion bioassay, co-inoculated mung bean seedlings recorded 9% and 8% higher shoot and root growth, respectively, compared to the control. Therefore, in conclusion, co-inoculation of the strains B. anthina and E. aerogenes displayed better performance in stimulating plant growth than inoculation of each strain alone. However, considering the short assessment period of the present study, we recommend engaging in further work under field conditions in order to test the suitability of these strains as bio-inoculants.