• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
• /
• pp.94.2-95
• /
• 2003

E. intermedium 60-2G possessing a strong ability to solubilize insoluble phosphate, has plant growth-promoting activity, induced systemic resistance activity against scab pathogen in cucumber, and antifungal activity against various phytopathogenic fungi. The phosphate solubilizing activity of 60-2G may be mainly accomplished by production of gluconic acid through a direct extracellular oxidation of glucose by glucose dehydrogenase that required a PQQ cofactor for its activation. A pqq gene cluster conferred Phosphate-solubilizing activity in E. coli DH5${\alpha}$ was cloned and sequenced. The 6,783 bP pqq sequence had six open reading frames (from A to F) and showed 50-95％ homology to pqq genes from other bacteria. The E. coli strain expressing the pqq genes solubilized phosphate from hydroxyapatite after a pH drop to 4.0, which paralleled in time the secretion of gluconic acid. To study the role of PQQ in biocontrol traits of E. intermedium, PQQ mutants of 60-2G were constructed by marker exchangee mutagenesis. The PQQ mutants of E. intermedium were lost activities of solubilizing phosphate, growth inhibition of phytopathogenic fungi, and plant growth promotion. These findings suggest that PQQ plays an important role, possibly activation of certain enzymes, in several beneficial bacterial traits of E. intermedium by as yet an unknown mechanism.

• Advances in Traditional Medicine
• /
• 제5권1호
• /
• pp.57-61
• /
• 2005

Ethanol and aqueous extracts of Cassia auriculata were tested in vitro against fungi (Candida albicans and Microsporum canis) and bacteria (Escherichia coli, Salmonella enteriditis, Staphylococcus aureus and Bacillus subtilis). M. canis showed dose-dependent susceptibility only towards ethanol leaf and bark extracts. C. albicans, were resistant to all types of plant extracts. Results were statistically smaller to antifungal drug ketoconazole and miconazole at equivalent concentration. Both ethanol and aqueous extracts of Cassia auriculata leaves and barks exhibit antibacterial activity against S. aureus and only the ethanol extracts of leaf and bark were detected against Bacillus subtilis. The results were compared to antibacterial drugs chloramphenicol, ampicillin, penicillin G, and enrofloxacin. The antibacterial activity was statistically similar to penicillin G. Based on the current findings, it can be concluded that this plant has antimicrobial activity, which is as potent as standard antimicrobial drugs.

• 한국균학회지
• /
• 제31권2호
• /
• pp.67-76
• /
• 2003

버섯 추출물의 병원 미생물에 대한 항균활성을 알아보기 위하여 66종의 버섯을 채집 동정하고, 이들을 석유에테르, 80% 에탄올 및 증류수로 추출하여 198종의 추출물을 얻은 후 19종의 인체 병원성 미생물에 대한 항균활성을 검정하였다. 그 결과, C. consors의 에탄올 추출물외에 13종의 추출물이 4종의 효모에, P. ostreatus의 에탄올 추출물 외 27종의 추출물이 3종의 사상균에, A. subrutilescons의 추출물외 78종의 추출물이 5종의 그람 음성세균에, 그리고 A. pseudoporphyria의 추출물외 59종의 추출물이 5종의 그람 양성세균에 항균활성을 보였다.

• 생명과학회지
• /
• 제8권2호
• /
• pp.173-180
• /
• 1998

미세 조류의 항균성 탐색을 위해 베를린 공대 생물공학 연구실에서 좀 균주을 분양받아 독일 현지 연구실에서 연구를 행하였다. 6종의 미세 조류로부터 항균성 시험 시료응 획득하기위해 먼저 배양데 따른 미세 죠류 배양액의 변화를 pH와 균제량으로 관찰하였고, 이를 토대로 시험 시료를 대주중식기와 정기기 두 구간으로 나누어 채취하였다. 얻어진 시료를 균체와 균체 상층액으로 분리하여 각족 용매를 이용하여 분획을 행하여 4-7종의 획분들 얻었거 이들이 가지는 항균 활성을 시험하였다. BGA(blue green algae) 4종류 중에서 Lsp(lyngbya sp.)와 Tsp(Tetraselmis sp.)에서 항균활성이 관측되었는데, 특히 균체외 상층액의 dthyl acetate 추출 획분이 서균과 특히 곰팡이에 대해 강력한 항균 활성이 있는 것으로 확인되었고, 그뢰 2종의 BGA 와 2종의 규조류(diatoms)에서는 항균 활성 획분이 확인되지 않았다.

• Journal of Microbiology and Biotechnology
• /
• 제18권5호
• /
• pp.990-996
• /
• 2008

In a previous study, we found an antifungal effect on human pathogenic fungi by the cell-penetrating peptide Tat (47-58) derived from HIV-1. Tat (47-58) immediately entered into the fungal nucleus and affected some physiological changes on the intracellular condition. In this study, Tat (47-58) showed a broad spectrum of antibacterial activity against pathogenic bacteria including bacterial clinical isolates. To improve resistance against proteases for use in vivo, we synthesized an analog of Tat (47-58) by substituting the L-amino acid for the D-amino acid. The D-enantiomer of Tat (47-58) also exhibited a broad spectrum of antibacterial activity at almost the same level of L-Tat (47-58) concentration. Unlike L-Tat (47-58), D-Tat (47-58) showed a significant proteolytic resistance against all proteases tested and antimicrobial activities in the presence of trypsin. Moreover, D-Tat (47-58) inhibited MRSA infection in human HeLa cells whereas L-Tat (47-58) partially allowed MRSA infection, and the results were due to the proteolytic resistance of D-Tat (47-58).

• Mycobiology
• /
• 제48권5호
• /
• pp.392-398
• /
• 2020

This study was conducted to understand the dynamics of microbial communities of soil microorganisms, and their distribution and abundance in the indigenous microorganisms (IMOs) manipulated from humus collected from the forest near the crop field. The soil microorganisms originated from humus and artificially cultured microbial-based soil amendments were characterized by molecular and biochemical analyses. The bacterial population (2 × 10⁶~13 × 10⁶ CFU/g sample) was approximately 100-fold abundant than the fungal population (2 × 10⁴~8 × 10⁴ CFU/g sample). The 16S rDNA and ITS sequence analyses showed that the bacterial and fungal communities in humus and IMOs were mainly composed of Bacillus and Pseudomonas, and Trichoderma and Aspergillus species, respectively. Some of the bacterial isolates from the humus and IMOs showed strong inhibitory activity against soil-borne pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. These bacteria also showed the siderophore production activity as well as phosphate solubilizing activity, which are requisite traits for biological control of plant pathogenic fungi. These results suggest that humus and IMOs could be a useful resource for sustainable agriculture.

• The Plant Pathology Journal
• /
• 제37권3호
• /
• pp.307-314
• /
• 2021

Pepper (Capsicum annuum L.) is an important agricultural crop worldwide. Recently, Colletotrichum scovillei, a member of the C. acutatum species complex, was reported to be the dominant pathogen causing pepper anthracnose disease in South Korea. In the present study, we isolated bacterial strains from rhizosphere soil in a pepper field in Gangwon Province, Korea, and assessed their antifungal ability against C. scovillei strain KC05. Among these strains, a strain named BS1 significantly inhibited mycelial growth, appressorium formation, and disease development of C. scovillei. By combined sequence analysis using 16S rRNA and partial gyrA sequences, strain BS1 was identified as Bacillus velezensis, a member of the B. subtilis species complex. BS1 produced hydrolytic enzymes (cellulase and protease) and iron-chelating siderophores. It also promoted chili pepper (cv. Nockwang) seedling growth compared with untreated plants. The study concluded that B. velezensis BS1 has good potential as a biocontrol agent of anthracnose disease in chili pepper caused by C. scovillei.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
• /
• pp.108.1-108
• /
• 2003

Soil metagenome is untapped total microbial genome including that of the majority of unculturable bacteria present in soil. We constructed soil metagenomic library in Escherichia coli using DNA directly extracted from two different soils, pine tree rhizosphere soil and forest topsoil. Metagenomic libraries constructed from pine tree rhizosphere soil and forest topsoil consisted of approximately 33,700 clones and 112,000 clones with average insert DNA size of 35-kb, respectively. Subsequently, we screened the libraries to select clones with antimicrobial activities against Saccharomyces cerevisiae and Agrobacterium tumefaciens using double agar layer method. So far, we have a clone active against S. cerevisiae and a clone active against A. tumefaciens from the forest topsoil library. In vitro mutagenesis and DNA sequence analysis of the antifungal clone revealed the genes involved in the biosynthesis of antimicrobial secondary metabolite. Metagenomic libraries constructed in this study would be subject to search for diverse genetic resources related with useful microbial products.

• 한국식물병리학회:학술대회논문집
• /
• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
• /
• pp.102.2-103
• /
• 2003

This studies were investigated the occurrence of Sclerotinia rot by Sclerotinia Sclerotiorum at the lettuce field in Uiryeong-Gun, Gyeongsangnam-Do and were isolated the most effective microorganism for the biological control to the pathogen, S. sclerotiorum YR-1 strain from diseased soil and lettuce leaves. For the pathogenicity test, the most suitable inoculmn density of YR-1 strain was selected as the mycelial suspension of 40m1 showing disease incidence of 80％, and the symptom showed as same as at the fields, the leaves and stem had rotten and developed white downy mycelial at the diseased lesion on the leaves and stems, and produced black and irregular sclerotinia. On the PDA dual test, about 300 isolates were examined the antifungal activity to the pathogen, YR-1 strain, and among them, A-2, A-7, and RH-4 strain were selected most effective antagonistic bacteria. At pots test, the control value of A-7 strain showed the highest value as 85％ which was more effective than that of others in a growth chamber. For the promotion of control effect, the selected 3 isolates were spayed on the lettuce leaves as a sole and/or mixed treatments in a growth chamber, the mixed treatment of A-7 and RH-4 strain showing the control value of 90％ was most effective than that of sole treatment with A-7 or RH-4 strain showing the control value of 80％, respectively and mixed treatment with A-2 and A-7 strain and A-2, A-7 and RH-4 strain. In addition, 3 bacteria re-isolated from diseased soils, and all of the selected 6 isolates investigated the control effect at pots in a growth chamber, According to the results, A-7 and Pro-EB 15 strain showed the control value of 91.0％ and 90.1％ respectively, and they were selected most effectual antagonistic bacteria to control lettuce sclerotinia rot and identified as the Bacillus mojanuinensis by 16s RNA analysis. This is the first report on the biological control using by B. mojanvinensis to the lettuce Sclerotinia rot.

• 대한소아치과학회지
• /
• 제36권1호
• /
• pp.1-11
• /
• 2009

Essential oil은 식물로부터 추출한 휘발성의 호지방성 화합물로서 essential oil은 잠재적으로 항균, 항진균, 진경련, 항말라리아성, 곤충퇴치능력 등의 생물학적 효과를 가지고 있다. 본 연구에서는 다양한 방향식물에서 추출한 Citral, Pineole, Linalool, Eugenol, Limonene, Pinene 등으로 구성된 다섯종류의 essential oil을 사용하였으며, 여덟 군의 중요한 병원성 세균인 Streptococcus mutans(S. mutans), Staphylococcus aureus(S. aureus), Streptococcus sanguis(S. sanguis), Streptococcus anginosus(S. anginosus), Actinobacillus actinomycetemcomitans(A. actinomycetem- comitans), Streptococcus sobrinus(S. sobrinus), Staphylococcus epidermidis(S. epidermidis), Esherichia coli (E. coli)에 대한 저항성으로서 항균능력을 평가하였다. Essential oil의 항균능력은 용액희석방법을 사용하여 검사하였으며, essential oil 농도범위는 10 mg/mL, 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.625 mg/mL, 0.516 mg/mL, 0.3125 mg/mL, 0.078 mg/mL, 0.039 mg/mL, 그리고 0.015 mg/mL였다. Essential oil은 용량 의존적으로 시험 균주의 성장을 효과적으로 억제하였으며, NM을 제외하고 R, LG, FR, O oil은 저농도에서 구강 병원성 미생물의 성장을 억제하였다. 또한 사용된 essential oil은 E.coli와 S. epidermidis의 성장에는 탁월한 억제효과를 보이지는 못했으나 구강 병원성 미생물에 대해서는 특별한 성장 억제효과를 나타냈다.