• 한국미생물·생명공학회지
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• 제25권3호
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• pp.335-337
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• 1997

In this study, we show a convenient MTT assay for detect the susceptibility of yeast-like form of Trichosporon beigelii against antifungal agents. This assay was developed based on mitocondrial respiration by determining reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan. Cells of T beigelii are seeded into 96-well microtiter plates, and antifungal agents, amphotericin B, magainin and CA-ME hybrid peptide were added with various concentrations. After 24 hr incubation, MTT was added, then incubations were continued for 4 hr. Formazan formation was quantified photometrically after extraction of the formazan with acid sodium dodesyl sulfate (SDS). From this assay, we could obtained MICs of antifungal agents against T. beigelii. The presented method can easily be used as an effective methods to assess the antiftingal action of various agents on yeasts with minimal amounts of antifungal agents.

• Journal of Microbiology and Biotechnology
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• 제20권8호
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• pp.1192-1195
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• 2010

To investigate the influence of the N- or C-terminal regions of pleurocidin (Ple) peptide on antifungal activity, four analogs partially truncated in the N- or C-terminal regions were designed and synthesized. Circular dichroism (CD) spectroscopy demonstrated that all the analogs maintained an alpha-helical structure. The antifungal susceptibility testing also showed that the analogs exhibited antifungal activities against human fungal pathogens, without hemolytic effects against human erythrocytes. The result further indicated that the analogs had discrepant antifungal activities [Ple>Ple (1-22)>Ple (4-25)>Ple (1- 19)>Ple (7-25)] and that N-terminal deletion affected the activities much more than C-terminal deletion. Hydrophobicity [Ple>Ple (1-22)>Ple (4-25)>Ple (1-19)> Ple (7-25)] was thought to have been one of the consistent factors that influenced these activity patterns, rather than the other primary factors like the helicity [Ple>Ple (4-25) >Ple (1-22)>Ple (1-19)>Ple (7-25)] or the net charge [Ple=Ple (4-25)=Ple (7-25)>Ple (1-22)=Ple (1-19)] of the peptides. In conclusion, the hydrophobic amino acids in the N-terminal region of Ple is more crucial for antifungal activity than those in the C-terminal region.

• 미생물학회지
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• 제33권3호
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• pp.170-174
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• 1997

강한 항진균 활성을 나타내며, 낮은 적혈구 용혈활성을 갖는 새로운 합성 펩티드를 얻기 위하여 cecropin A(1-8)-magainin 2(1-12) 및 이들의 유사체들을 설계하고 이들을 고상법에 의하여 합성하였다. 합성 펩티드의 항진균 활성은 Trichosporon beigelii에 대한 성장억제능에 의하여 측정하였으며, 세포독성은 인간의 적혈구 세포에 대한 용혈활성에 의하여 측정하였다. 펩티드의 양쪽 친매성의 증가는 항진균활성보다는 적혈구 용혈황성에 큰 영향을 미쳤다. Cecropin A(1-8)-magainin 2(1-12)의 12번 아미노산이 Lys을 Ala으로 치환시킨 유사체 펩티드(A2)는 가장 강한 항진균활성(minimum inhibitory concentration : 2.5.$\mu$g/ml)을 나타내며 비교적 낮은 적혈구 용혈활성(200.$\mu$g/ml의 펩티드 농도에서 0.5% hemolysis를 나타냄)을 나타내었다. 따라서 A2의 펩티드는 세포독성을 갖지 않으며 강한 항진균 활성을 가지는 모델로서 유용하게 사용될 것이다.

• Journal of Microbiology
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• 제34권3호
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• pp.274-278
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• 1996

Two peptides, MA-inv AND MA-ME, with the sequence 10-17 of maganin 2 at their-N-termini were designed and synthesized. The peptides had higher antifungal activities against Aspergilus fumigatus without hemolytic activities. The minimal inhibition concentratory (MIC) values of both peptides against A. fumigatus were 5 .mu.g/ml, whereas those of the native peptides, magainin 2 and melittin, were 10.mu.g/ml. At 3 .mu.g/ml, MA-inv and MA-ME inhibited the mycelium growth of A. fumigatus by 94.6% and 97.3% respectively, whereas magainin 2 and melittin inhibited by 62.2% and 32.4, respectively. MA-inv showed up to 80% inhibition of (1, 3)-.betha.-D-glucan synthase activity of A. fumigatus. The peptides also showed up to 80% inhibition of (1, 3)-.betha.-D glucan synthase activity of A. fumigatus. The peptides also showed antifungal activities for other fungi of Aspergillus sp. However, the antibiotic activities of MA-ME against Escherichia coli, Bacillus subtilis and Fusarium oxysporum were more effective than those of MA-inv, suggesting that the C-terminal sequences of MA-inv and MA-ME may also influence their antibiotic activities. These results suggest that the N-terminal sequence of the designed peptides, KKFGKAFV, is important for their antifungal activities against A. fumigatus and their C- terminal sequences are related to the organism selectivity.

• 약학회지
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• 제55권3호
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• pp.227-233
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• 2011

We previously reported the protein isolated from Coptidis Rhizoma (CRP), which has antifungal activity against a fungal pathogen, Candida albicans. In the current study, we investigated what portion in the CRP is responsible for the antifungal activity. For the investigation, the CRP was fractionated on a Shepadex G-50 column. Data resulting from the fractionation, seven fractions were obtained. Fractions (Fr.) I, II, and III eluted initially from the column showed no inhibitory effect on the growth of C. albicans, whereas Fr. IV, V, and VI eluted later revealed inhibition of the growth, and Fr. IV and VI showed potent antifungal activity by broth susceptibility analysis. However, Fr. VI was contained in the CRP more than Fr. IV, which led us to select the VI for the following experiments. In a murine model of a subcutaneous candidiasis caused by C. albicans, the Fr. VI displayed a therapeutic effect on nude mice pretreated with anti-neutrophil monoclonal antibody (RB68C5) and then infected subcutaneously with live C. albicans. At day 16, these mice were healed almost up to 78% of the infected area when compared to infected area of control nude mice that received diluent (Dulbecco's Phosphate-Buffered Saline; DPBS), instead of the Fr. VI (P<0.01). The Fr. VI blocked hyphal formation from blastoconidial form of C. albicans (P<0.01), which might prevent penetration of hyphae to the deeper site of skin and thus helps the healing. In the ionic strength test, the effect of Fr. was influenced by $Ca^{2+}$ ion just like other known antimicrobial peptides, but the influence was affected at an extremely high concentration such as 500 mM. Thus, such ion-concentration is considered to be meaningless in the clinical situation. Considering all data together, Coptidis Rhizoma is appeared to produce an antimicrobial peptide that has therapeutic effect on subcutaneous infection caused by C. albicans.

• Journal of Microbiology and Biotechnology
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• 제18권5호
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• pp.880-884
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• 2008

A strain of Streptomyces sp. (M10) antagonistic to Botrytis cinerea was isolated from orchard soil obtained from Jeju Island, Korea. An antifungal substance (CN1) was purified from the culture extracts of the strain, and then identified as valinomycin through extensive spectroscopic analyses. Valinomycin showed potent in vitro antifungal activity against Botrytis cinerea and also in vivo control efficacy against Botrytis blight development in cucumber plants. Overall, the disease control efficacy of valinomycin was similar to that of vinclozolin, a commercial fungicide. This study provides the first report on the disease control efficacy of valinomycin against Botrytis blight.

• The Plant Pathology Journal
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• 제31권3호
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• pp.316-321
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• 2015

A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of $50{\mu}g/ml$, although one isolate of Fusarium oxysporum was inhibited at $5{\mu}g/ml$ of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with $50{\mu}g/ml$ of JH8944. Germinating F. graminearum conidia required $238{\mu}g/ml$ of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of $250{\mu}g/ml$ even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and $50{\mu}g/ml$ of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.149-153
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• 2017

원목과 톱밥배지에서 푸른곰팡이의 오염과 성장은 표고버섯의 생장을 심하게 저해할 수 있다. 표고버섯 재배에서 푸른곰팡이병의 방제를 위하여 농약과 항생제와 같은 화학 약품의 사용은 일반적으로 허용되지 않는다. 본 연구에서는 푸른곰팡이병의 방제를 위하여 느타리버섯에서 갈반병을 일으키는 세균성 병원균을 분리하고 이들의 펩티드 독소를 분리하였다. Pseudomonas tolaasii 균주들은 항진균 활성을 갖는 톨라신 및 이와 구조적 유사체인 다양한 펩티드 독소를 분비한다. 이러한 펩티드들은 표고버섯의 생장에는 영향을 주지 않는다는 것이 알려져 있다. 펩티드 독소들을 Trichoderma harzianum H1 푸른곰팡이에 처리하였을 때, 푸른곰팡이의 성장을 저해하였다. 펩티드를 분비하는 20 종의 P. tolaasii 균주 중에서 강, 중, 약의 항진균 활성을 가진 균주의 수는 각각 8, 5, 7 종으로 나타났다. 표고버섯을 재배하는 동안에, 펩티드 독소를 함유한 세균 배양액에서 세균을 제거한 배양원액을 톱밥배지 표면에 자란 푸른곰팡이 균사에 분무하였다. 배양원액은 푸른곰팡이의 성장은 억제할 수 있는 반면, 표고버섯 생장과 생산에는 영향을 주지 않았다. 펩티드 독소를 함유하는 배양원액은 곰팡이의 흰색 균사체를 노란색의 마른 딱지로 변화시켰고, 이것은 펩티드 독소가 강력한 항진균 활성과 살균 활성을 갖고 있음을 보여준다.

• Preventive Nutrition and Food Science
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• 제17권1호
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• pp.64-70
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• 2012

Bacilli with fibrinolytic activities were isolated from traditionally-prepared Meju and some of these strains showed strong antifungal activities. One isolate, MJ1-4, showed the strongest antifungal activity. MJ1-4 and other isolates were identified as B. amyloliquefaciens strains by recA gene sequencing and RAPD-PCR results. B. amyloliqufaciens MJ1-4 efficiently inhibited an Aspergillus spp.-producing aflatoxin B1 ($AFB_1$) and a Penicillium spp.-producing ochratoxin (OTA) in addition to other fungi. Antifungal activity of B. amyloliquefaciens MJ1-4 culture reached its maximum (40 AU/mg protein) in LB or TSB medium around 48 hr at $37^{\circ}C$. Antifungal activity of the concentrated culture supernatant was not decreased significantly by protease treatments, implying that the antifungal substance might not be a simple peptide or protein. Considering its antifungal and fibrinolytic activities together, B. amyloliquefaciens MJ1-4 can serve as a starter for fermented soyfoods such as Cheonggukjang and Doenjang.

• Journal of Microbiology
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• 제35권1호
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• pp.21-24
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• 1997

The hybrid peptides, CA-ME, CA-MA and CA-BO, with the N-terminal sequence 1-8 of cecropin A and the N-terminal sequences 1-12 of melittin, magainin 2 and bombinin, respectively, have more improved antibacterial activities. CA-MA was found to have stronger antifungal activity against Trichoderma sp than other hybrid peptides and their parental peptides. In order to elucidate the relationships between the peptide structure and antifungal activity, several analogues of CA-MA or CA-BO were also designed and synthesized by the solid phase method. An tifungal activity was measured against T. reesei and T. viride, and hemolytic activity was measured by a solution method against human red blood cells. The residue 16 of CA-MA, Ser, was found to be important for antifungal activity. When the residue was substituted with Leu, showed powerful antifungal activity was dramatically decreased. CA-MA, P1, P4 and P5 designed in this study showed powerful antifungal activity against T. reesei and T. viride with low hemolytic activity against human red blood cells. These hybrid peptides will be potentially useful model to further design peptides with powerful antifungal activity for the effective therepy of fungal infection and understand the mechanisms of antifungal actions of hybrid peptides.