• Title, Summary, Keyword: antifungal peptide

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Antifungal Activities of Magainin-2 Hybrid Peptides against Trichosporon beigelii

  • LEE, DONG GUN;SONG YUB SHIN;SUNG GU LEE;KIL LYONG KIM;MYUNG KYU LEE;KYUNG SOO HAHM
    • Journal of Microbiology and Biotechnology
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    • v.7 no.1
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    • pp.49-51
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    • 1997
  • In order to obtain a hybrid synthetic peptide with a more potent antifungal activity than magainin-2 but without hemolytic activity, four hybrid peptides were designed from the sequences of magainin 2 and cecropin A and their antifungal activities against Trichosporon beigelii were investigated. The result showed that analogue 2 and 4 exhibited better antifungal activity against T. beigelii than magainin-2 but no hemolytic activities. The peptides, therefore, could be used as models for the development of potent antifungal peptides.

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Antifungal Mechanism of Antifungal Peptide Derived from Cecropin A(1-8)- Melittin(1-12) Hybrid against Aspergillus fumigatus

  • Lee, Dong-Gun;Jin, Zhe-Zhu;Maeng, Cheol-Young;Shin, Song-Yub;Seo, Moo-Yeol;Kim, Kil-Lyong;Hahm, Kyung-Soo
    • Journal of Microbiology and Biotechnology
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    • v.9 no.2
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    • pp.168-172
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    • 1999
  • The antifungal mechanism of the antifungal peptide against Aspergillus fumigatus, $K^{18,19}$-CA(l-8)-ME(l-12), derived from cecropin A(l-8)-melittin(l-12) was investigated by confocal laser scanning microscopy, cell wall regeneration, ATPase activity inhibition, and released potassium ion. By confocal laser scanning microscopy, $K^{18,19}$-CA(l-8)-ME(l-12) was detected on the surface of A. fumigatus, while cecropin A used as a negative control peptide was not detected. The protoplast of A. fumigatus treated with$K^{18,19}$-CA(1-8)-ME(1-12) failed to regenerate the fungal cell walls. Compared with cecropin A, the amount of potassium ion released by $K^{18,19}$-CA(l-8)-ME(l-12) was increased. Furthermore, $K^{18,19}$-CA(l-8)-ME(l-12) inhibited the ATPase activity on the plasma membrane. These results suggested that $K^{18,19}$-CA(l-8)-ME(1-12) acts on the plasma membrane of A. fumigatus and its antifungal action is due to the ion channel or pore formation on the plasma membrane.

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Purification and Characterization of an Antifungal Peptide from the Seeds of Phytolacca americana (미국자리공 종실로부터 항균성 펩타이드의 분리 및 특성 연구)

  • 손대영;신봉정;윤대진;성기영;정영륜
    • Korean Journal Plant Pathology
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    • v.14 no.3
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    • pp.203-208
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    • 1998
  • We isolated and characterized an antifungal peptide from the seeds of Phytolacca americana. Growth inhibition assay with Botrytis cinerea was used to screen inhibitory proteins from 60 different plant species. A 4 kDa antifungal peptide (Pa-AFP) inhibitory to hyphal growth of B. cinerea was found in the seeds of P. americana. The peptide Pa-AFP was purified to homogeneity by chromatographies of Sephadex G-50, DEAE-Sepharose, Sephacryl S-300, and C18 reverse-phase HPLC. Western blot analysis showed that a polyclonal antibody raised against the purified peptide cross-reacted with a 4 kDa protein in seeds but not in root and leaf tissues of P. americana. Pa-AFP inhibited the hyphal growth of Botrytis cinerea, Rihzoctonia solani, Fusarium oxysporum, and Magnaporthe grisea. Pa-AFP exhibited growth inhibition of Saccharomyces cerevisiae strain BWG7a, which was sensitive to osmotin.

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A Novel Antifungal Analog Peptide Derived from Protaetiamycine

  • Lee, Juneyoung;Hong, Hyun Joo;Kim, Jin-Kyoung;Hwang, Jae-Sam;Kim, Yangmee;Lee, Dong Gun
    • Molecules and Cells
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    • v.28 no.5
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    • pp.473-477
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    • 2009
  • Previously, the 9-mer analog peptides, 9Pbw2 and 9Pbw4, were designed based on a defensin-like peptide, protaetiamycine isolated from Protaetia brevitarsis. In this study, antifungal effects of the analog peptides were investigated. The antifungal susceptibility testing exhibited that 9Pbw4 contained more potent antifungal activities than 9Pbw2. A PI influx assay confirmed the effects of the analog peptides and demonstrated that the peptides exerted their activity by a membrane-active mechanism, in an energy-independent manner. As the noteworthy potency of 9Pbw4, the mechanism(s) of 9Pbw4 were further investigated. The membrane studies, using rhodamine-labeled giant unilamellar vesicle (GUV) and fluorescein isothiocyanate (FITC)-dextran loaded liposome, suggested that the membrane-active mechanism of 9Pbw4 could have originated from the pore-forming action and the radii of pores was presumed to be anywhere from 1.8 nm to 3.3 nm. These results were confirmed by 3D-flow cytometric contour-plot analysis. The present study suggests a potential of 9Pbw4 as a novel antifungal peptide.

Potentiality of Oligodeoxynucleotides as An Inducer for Antifungal Peptide in Two Lepidopteran Insects, Bombyx mori and Galleria mellonella

  • Kim, Iksoo;Lee, Young-Shin;Lee, Kwang-Sik;Cha, So-Young;Kang, Pil-Don;Sohn, Bong-Hee;Lee, In-Hee;Jin, Byung-Rae;Hwang, Jae-Sam
    • International Journal of Industrial Entomology
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    • v.8 no.1
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    • pp.95-99
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    • 2004
  • Synthetic oligodeoxynucleotides (ODNs) containing unmethylated CpG dinucleotides in particular base contexts are known to induce immunity in vertebrate cells. In insect, however, it was recent to find out that ODNs induces insect immunity as other immune inducer such as lipopolysaccharide. However, the finding was solely based on one lepidopteran insect, Bombyx mori, and the expression of insect immunity was neither dependent on numbers of CpG repeats nor methylation of CpG repeats within ODNs. Instead, foreignness of DNA has been suggested to be a key factor governing induction of antibacterial peptide. In this study, we expanded our previous understanding to the potentiality of ODNs as an immune inducer for antifungal peptide in Galleria mellonella and B. mori. To do this, a defensin-type antifungal peptide gene, reported from G. mellonella was cloned and partially sequenced from G. mellonella and B. mori successfully and utilized as a probe in the Northern blot analysis. We found out that ODNs also work as an immune inducer for antifungal peptide in the fat body and midgut of G. mellonella and B. mori larvae. Also, induction pattern of antifungal peptide was irrelevant to the numbers of CpG repeats within ODNs as previously reported on the induction pattern of antibacterial peptides.

Structure-Antifungal Activity Relationships of Cecropin A-Magainin 2 and Cecropin A-Melittin Hybrid Peptides on Pathogenic Fungal Cells

  • Lee, Dong-Gun;Jin, Zhe-Zhu;Shin, Song-Yub;Kang, Joo-Hyun;Hahm, Kyung-Soo;Kim, Kil-Lyong
    • Journal of Microbiology and Biotechnology
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    • v.8 no.6
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    • pp.595-600
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    • 1998
  • In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

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Structure and Antibiotic Activity of Fragment Peptides of Antifungal Protein Isolated From Aspergillus giganteus

  • Shin, Song-Yub;Kang, Joo-Hyun;Lee, Dong-Gun;Jin, Zhe-Zhu;Jang, So-Youn;Kim, Kil-Lyong;Hahm, Kyung-Soo
    • Journal of Microbiology and Biotechnology
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    • v.9 no.3
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    • pp.276-281
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    • 1999
  • In order to determine the functional region of the antifungal protein (AFP) isolated from Aspergillus giganteus responsible for growth inhibitory activity and the promotion of phospholipid vesicle aggregation, overlapping peptides covering the complete sequence of AFP were synthesized. The antibiotic activity against bacterial, fungal, and tumor cells, and the vesicle-aggregation activity of the synthetic peptides were investigated. The AFP functional sequence responsible for antibiotic and vesicle-aggregation activity was determined to be located within the region between AFP residues 19 to 32. AFP (19-32) exhibited an a-helical conformation in a cell membrane-like environment. AFP (19-32) displayed potent antibiotic activity against bacterial, fungal, and tumor cells without peptide toxicity as indicated by hemolysis. Accordingly, AFP (19-32) could be used as a good model for the design of effective antibiotic agents with powerful antibiotic activity yet without any cytotoxic effects against the host organism.

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Cloning, Characterization and Antifungal Activity of Defensin Tfgd1 from Trigonella foenum-graecum L.

  • Olli, Sudar;Kirti, P.B.
    • BMB Reports
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    • v.39 no.3
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    • pp.278-283
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    • 2006
  • Defensins are small cysteine rich peptides with a molecular mass of 5-10 kDa and some of them exhibit potent antifungal activity. We have cloned the coding region of a cDNA of 225 bp cysteine rich defensin, named as Tfgd1, from the legume Trigonella foenum-graecum. The amino acid sequence deduced from the coding region comprised 74 amino acids, of which the N-terminal 27 amino acids constituted the signal peptide and the mature peptide comprised 47 amino acids. The protein is characterized by the presence of eight cysteine resisdues, conserved in the various plant defensins forming four disulphide bridges, which stabilize the mature peptide. The recombinant protein expressed in E coli exhibited antifungal activity against the broad host range fungus, Rhizoctonia solani and the peanut leaf spot fungus, Phaeoisariopsis personata.

Isolation and Characterization of Two Amino Acid-activating Domains of Peptide Synthetase Gene from Bacillus subtilis 713

  • Lee, Youl-Soon;You, Sang-Bae;Lee, Ji-Wan;Kim, Tae-Young;Kim, Sung-Uk;Bok, Song-Hae
    • Journal of Microbiology and Biotechnology
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    • v.8 no.4
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    • pp.399-405
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    • 1998
  • From the sequence alignment of various non-ribosomal peptide synthetases, several motifs of highly conserved sequences have been identified within each domain of peptide synthetases. We designed PCR primers based on the highly conserved nucleotide sequences to amplify and isolate a ∼7.2-kb DNA fragment of the Bacillus subtilis 713 which was isolated and reported to produce an antifungal peptide compound. Nucleotide sequence analysis of 4.8 kb of the predicted amino acids revealed significant homology to various peptide synthetases over the whole sequence and also revealed two amino acid-activating domains with highly conserved Core 1 to Core 6 and spacer motif. This suggests that the isolated DNA fragment is part of a peptide synthetase gene for antifungal peptide.

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Influence of the Hydrophobic Amino Acids in the N- and C-Terminal Regions of Pleurocidin on Antifungal Activity

  • Lee, June-Young;Lee, Dong-Gun
    • Journal of Microbiology and Biotechnology
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    • v.20 no.8
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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.