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Lee J, Choi Y, Woo ER, Lee DG. Isocryptomerin, a novel membrane-active antifungal compound from Selaginella tamariscina. Biochem Biophys Res Commun 2009; 379:676-80. [DOI: 10.1016/j.bbrc.2008.12.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
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52
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Wiederhold NP, Lewis RE, Wiederhold NP, Lewis RE. Antifungal activity againstScedosporiumspecies and novel assays to assess antifungal pharmacodynamics against filamentous fungi. Med Mycol 2009; 47:422-32. [DOI: 10.1080/13693780802510224] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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53
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Barchiesi F, Silvestri C, Arzeni D, Ganzetti G, Castelletti S, Simonetti O, Cirioni O, Kamysz W, Kamysz E, Spreghini E, Abruzzetti A, Riva A, Offidani AM, Giacometti A, Scalise G. In vitrosusceptibility of dermatophytes to conventional and alternative antifungal agents. Med Mycol 2009; 47:321-6. [DOI: 10.1080/13693780802641920] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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54
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Park SC, Yoo NC, Kim JY, Park HK, Chae BJ, Shin SY, Cheong H, Park Y, Hahm KS. Isolation and characterization of an extracellular antimicrobial protein from Aspergillus oryzae. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:9647-9652. [PMID: 18803391 DOI: 10.1021/jf802373h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A 17 kDa antimicrobial protein was isolated from growth medium containing the filamentous fungus Aspergillus oryzae by extracting the supernatants from the culture media, ion exchange chromatography on CM-sepharose, and C18 reverse-phase high-performance liquid chromatography. This antimicrobial protein, which we considered to be an extracellular antimicrobial protein from A. oryzae (exAP-AO17), possessed antimicrobial activity but lacked hemolytic activity. The exAP-AO17 protein strongly inhibited pathogenic microbial strains, including pathogenic fungi, Fusarium moniliform var. subglutinans and Colletotrichum coccodes, and showed antibacterial activity against bacteria, including E. coli O157 and Staphylococcus aureus. To confirm that the protein acts as a regulation factor for extracellular secretion, we examined growth under varying conditions of N sources, C sources, ions, ambient pH, and stress. Various culture conditions were found to induce characteristic changes in the expression of protein synthesis as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Highly basic polypeptides were regulated by suppressing the ambient pH under acidic conditions and strongly induced under alkaline conditions, thus confirming that pH regulation is physiologically relevant. The expression of exAP-AO17 was upregulated by heat shock upon growth in the presence of NaCl. Automated Edman degradation showed that the N-terminal sequence of exAP-AO17 was NH 2-GLPGPAGAVGFAGKDQNM-. ExAP-AO17 showed partial sequence homology with a collagen belonging to the animal source. These results suggest that exAP-AO17 is an excellent candidate as a lead compound for the development of novel oral or other types of anti-infective agents.
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Affiliation(s)
- Seong-Cheol Park
- Research Center for Proteineous Materials (RCPM), Chosun University, Gwangju, 501-759, Korea
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55
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Raut U, Narang P, Mendiratta DK, Narang R, Deotale V. EVALUATION OF RAPID MTT TUBE METHOD FOR DETECTION OF DRUG SUSCEPTIBILITY OF MYCOBACTERIUM TUBERCULOSIS TO RIFAMPICIN AND ISONIAZID. Indian J Med Microbiol 2008. [DOI: 10.1016/s0255-0857(21)01866-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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56
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Thionin Thi2.1 from Arabidopsis thaliana expressed in endothelial cells shows antibacterial, antifungal and cytotoxic activity. Biotechnol Lett 2008; 30:1713-9. [PMID: 18563581 DOI: 10.1007/s10529-008-9756-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/14/2008] [Accepted: 05/27/2008] [Indexed: 10/21/2022]
Abstract
Thionins are plant antimicrobial peptides with antibacterial and antifungal activities. Thionin Thi2.1 cDNA from Arabidopsis thaliana was expressed in BVE-E6E7 bovine endothelial cell line and its activity was evaluated against Escherichia coli, Staphylococcus aureus, Candida albicans and different mammal cell lines. Total protein (2.5 microg) from conditioned medium (CM) of clone EC-Thi2.1 inhibited the growth of E. coli, S. aureus (>90%) and C. albicans strains (>80%) in relation to the CM from control cells. Also, CM of EC-Thi2.1 inhibited the viability of several transformed and normal mammal cell lines (38-95%). These results suggest that thionin Thi2.1 is an antimicrobial peptide that could be use in the treatment of mammalian infectious diseases.
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Silva WJD, Seneviratne J, Parahitiyawa N, Rosa EAR, Samaranayake LP, Cury AADB. Improvement of XTT assay performance for studies involving Candida albicans biofilms. Braz Dent J 2008; 19:364-9. [DOI: 10.1590/s0103-64402008000400014] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 10/24/2008] [Indexed: 11/22/2022] Open
Abstract
2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay has been used to study Candida biofilm formation. However, considering that the XTT reduction assay is dependent on cell activity, its use for evaluating mature biofilms may lead to inaccuracies since biofilm bottom cell layers tend to be relatively quiescent at later stages of biofilm formation. The aim of this study was to improve XTT reduction assay by adding glucose supplements to the standard XTT formulation. Candida albicans ATCC 90028 was used to form 24-, 48- and 72-h biofilms. The oxidative activity at 90, 180 and 270 min of incubation was evaluated. The control consisted of standard XTT formulation without glucose supplements, and was modified by the addition of 50, 100 and 200 mM of glucose. The XTT assay with 200 mM glucose showed more accurate and consistent readings correlating with biofilm development at 24, 48 and 72 h. Biofilm growth yield after 180 min incubation, when evaluated with the 200 mM glucose supplemented XTT, produced the most consistent readings on repetitive testing. It may be concluded that glucose supplementation of XTT could minimize variation and produce more accurate data for the XTT assay.
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58
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Arseculeratne SN, Atapattu DN, Kumarasiri R, Perera D, Ekanayake D, Rajapakse J. THE USE OF MTT [3-(4, 5-DIMETHYL-2-THIAZOLYL) -2, 5-DIPHENYL - 2H- TETRAZOLIUM BROMIDE]-REDUCTION AS AN INDICATOR OF THE EFFECTS OF STRAIN-SPECIFIC, POLYCLONAL RABBIT ANTISERA ON CANDIDA ALBICANS AND C. KRUSEI. Indian J Med Microbiol 2007. [DOI: 10.1016/s0255-0857(21)02120-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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59
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Jung HJ, Park Y, Sung WS, Suh BK, Lee J, Hahm KS, Lee DG. Fungicidal effect of pleurocidin by membrane-active mechanism and design of enantiomeric analogue for proteolytic resistance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1400-5. [PMID: 17467656 DOI: 10.1016/j.bbamem.2007.02.024] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 02/26/2007] [Accepted: 02/28/2007] [Indexed: 11/17/2022]
Abstract
Pleurocidin (Ple) is a 25-residue peptide which is derived from the skin mucous secretion of the winter flounder (Pleuronectes americanus). In this study, we investigated antifungal effects and its mode of action of Ple on human pathogenic fungi. Ple showed potent antifungal activity with low hemolytic activity. To investigate the antifungal mechanisms of Ple, the cellular localization and membrane interaction of Ple were examined. Protoplast regeneration and membrane-disrupting activity by DPH-labeled membrane support the idea, that Ple exerts fungicidal activity against the human pathogenic fungus Candida albicans with the disruption of a plasma membrane. To aim for which was the application of a therapeutic agent, we designed a synthetic enantiomeric peptide composed of all-d-amino acids to enhance proteolytic resistance. The synthetic all-d-Ple also displayed two-fold more potent antifungal activity than that of all-l-Ple, and its antifungal activity showed proteolytic resistance against various proteases. Therefore, these results suggest a therapeutic potential of all-d-Ple with regard to its proteolytic resistance against human fungal infections.
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Affiliation(s)
- Hyun Jun Jung
- Department of Microbiology, College of Natural Sciences, Kyungpook National University, 1370 Sankyuk-dong, Puk-ku, Daegu 702-701, Republic of Korea
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60
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Park Y, Park SC, Park HK, Shin SY, Kim Y, Hahm KS. Structure-activity relationship of HP (2-20) analog peptide: enhanced antimicrobial activity by N-terminal random coil region deletion. Biopolymers 2007; 88:199-207. [PMID: 17216635 DOI: 10.1002/bip.20679] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
HP (2-20) (AKKVFKRLEKLFSKIQNDK) is a 19-aa antimicrobial peptide derived from N-terminus of Helicobacter pylori Ribosomal protein L1 (RpL1). In the previous study, several analogs with amino acid substitutions were designed to increase or decrease only the net hydrophobicity. In particular, substitutions of Gln(16) and Asp(18) with Trp (Anal 3) for hydrophobic amino acid caused a dramatic increase in antibiotic activity without a hemolytic effect. HP-A3 is a potent antimicrobial peptide that forms, in a hydrophobic medium, an amphipathic structure consisting of an N-terminal random coil region (residues 2-5) and extended C-terminal regular alpha-helical region (residues 6-20). To obtain the short and potent alpha-helical antimicrobial peptide, we synthesized a N-terminal random coil deleted HP-A3 (A3-NT) and examined their antimicrobial activity and mechanism of action. The resulting 15mer peptide showed increased antibacterial and antifungal activity to 2- and 4-fold, respectively, without hemolysis. Confocal fluorescence microscopy studies showed that A3-NT was accumulated in the plasma membrane. Flow cytometric analysis revealed that A3-NT acted in salt- and energy-independent manner. Furthermore, A3-NT causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy. Circular dichroism (CD) analysis revealed that A3-NT showed higher alpha-helical contents than the HP-A3 peptide in 50% TFE solution. Therefore, the cell-lytic efficiency of HP-A3, which depended on the alpha-helical content of peptide, correlated linearly with their antimicrobial potency.
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Affiliation(s)
- Yoonkyung Park
- Research Center for Proteineous Materials, Chosun University, Kwangju, Korea
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Ryu JH, Ha EM, Oh CT, Seol JH, Brey PT, Jin I, Lee DG, Kim J, Lee D, Lee WJ. An essential complementary role of NF-kappaB pathway to microbicidal oxidants in Drosophila gut immunity. EMBO J 2006; 25:3693-701. [PMID: 16858400 PMCID: PMC1538556 DOI: 10.1038/sj.emboj.7601233] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Accepted: 06/20/2006] [Indexed: 02/07/2023] Open
Abstract
In the Drosophila gut, reactive oxygen species (ROS)-dependent immunity is critical to host survival. This is in contrast to the NF-kappaB pathway whose physiological function in the microbe-laden epithelia has yet to be convincingly demonstrated despite playing a critical role during systemic infections. We used a novel in vivo approach to reveal the physiological role of gut NF-kappaB/antimicrobial peptide (AMP) system, which has been 'masked' in the presence of the dominant intestinal ROS-dependent immunity. When fed with ROS-resistant microbes, NF-kappaB pathway mutant flies, but not wild-type flies, become highly susceptible to gut infection. This high lethality can be significantly reduced by either re-introducing Relish expression to Relish mutants or by constitutively expressing a single AMP to the NF-kappaB pathway mutants in the intestine. These results imply that the local 'NF-kappaB/AMP' system acts as an essential 'fail-safe' system, complementary to the ROS-dependent gut immunity, during gut infection with ROS-resistant pathogens. This system provides the Drosophila gut immunity the versatility necessary to manage sporadic invasion of virulent pathogens that somehow counteract or evade the ROS-dependent immunity.
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Affiliation(s)
- Ji-Hwan Ryu
- Division of Molecular Life Science and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul, South Korea
| | - Eun-Mi Ha
- Division of Molecular Life Science and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul, South Korea
| | - Chun-Taek Oh
- Laboratory of Innate Immunology, Institut Pasteur Korea, Seoul, South Korea
| | - Jae-Hong Seol
- School of Biological Science, Seoul National University, Seoul, South Korea
| | - Paul T Brey
- Unité de Biochimie et Biologie Moléculaire, Institut Pasteur, Paris, France
| | - Ingnyol Jin
- Department of Microbiology, Kyungpook National University, Daegu, South Korea
| | - Dong Gun Lee
- Department of Microbiology, Kyungpook National University, Daegu, South Korea
| | - Jaesang Kim
- Division of Molecular Life Science and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul, South Korea
| | - Daekee Lee
- Division of Molecular Life Science and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul, South Korea
| | - Won-Jae Lee
- Division of Molecular Life Science and National Creative Research Initiative Center for Symbiosystem, Ewha Woman's University, Seoul, South Korea
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62
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Cos P, Vlietinck AJ, Berghe DV, Maes L. Anti-infective potential of natural products: how to develop a stronger in vitro 'proof-of-concept'. JOURNAL OF ETHNOPHARMACOLOGY 2006; 106:290-302. [PMID: 16698208 DOI: 10.1016/j.jep.2006.04.003] [Citation(s) in RCA: 742] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/01/2006] [Accepted: 04/03/2006] [Indexed: 05/09/2023]
Abstract
Natural products, either as pure compounds or as standardized plant extracts, provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity. To secure this, a number of pivotal quality standards need to be set at the level of extract processing and primary evaluation in pharmacological screening models. This review provides a number of recommendations that will help to define a more sound 'proof-of-concept' for antibacterial, antifungal, antiviral and antiparasitic potential in natural products. An integrated panel of pathogens is proposed for antimicrobial profiling, using accessible standard in vitro experimental procedures, endpoint parameters and efficacy criteria. Primary requirements include: (1) use of reference strains or fully characterized clinical isolates, (2) in vitro models on the whole organism and if possible cell-based, (3) evaluation of selectivity by parallel cytotoxicity testing and/or integrated profiling against unrelated micro-organisms, (4) adequately broad dose range, enabling dose-response curves, (5) stringent endpoint criteria with IC(50)-values generally below 100microug/ml for extracts and below 25microM for pure compounds, (6) proper preparation, storage and in-test processing of extracts, (7) inclusion of appropriate controls in each in vitro test replicate (blanks, infected and reference controls) and (8) follow-up of in vitro activity ('hit'-status) in matching animal models ('lead'-status).
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Affiliation(s)
- Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
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63
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Anaya-López JL, López-Meza JE, Baizabal-Aguirre VM, Cano-Camacho H, Ochoa-Zarzosa A. Fungicidal and cytotoxic activity of a Capsicum chinense defensin expressed by endothelial cells. Biotechnol Lett 2006; 28:1101-8. [PMID: 16794772 DOI: 10.1007/s10529-006-9060-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
Plant defensins are antimicrobial peptides that exhibit mainly antifungal activity against a broad range of plant fungal pathogens. However, their actions against Candida albicans have not been extensively studied. The mRNA for gamma-thionin, a defensin from Capsicum chinense, has been expressed in bovine endothelial cells. The conditioned medium of these cells showed antifungal activity on germ tube formation (60-70% of inhibition) and on the viability of C. albicans (70-80% of inhibition). Additionally, C. albicans was not able to penetrate transfected cells. Conditioned medium from these cells also inhibited the viability (80%) of the human tumor cell line, HeLa.
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Affiliation(s)
- José L Anaya-López
- Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
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64
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Kim MH, Park SC, Kim JY, Lee SY, Lim HT, Cheong H, Hahm KS, Park Y. Purification and characterization of a heat-stable serine protease inhibitor from the tubers of new potato variety "Golden Valley". Biochem Biophys Res Commun 2006; 346:681-6. [PMID: 16777063 DOI: 10.1016/j.bbrc.2006.05.186] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 05/22/2006] [Indexed: 10/24/2022]
Abstract
Potide-G, a small (5578.9 Da) antimicrobial peptide, was isolated from potato tubers (Solanum tuberosum L. cv. Golden Valley) through extraction of the water-soluble fraction, dialysis, ultrafiltration and DEAE-cellulose and C18 reverse-phase high performance liquid chromatography. This antimicrobial peptide was heat-stable and almost completely suppressed the proteolytic activity of trypsin, chymotrypsin and papain, with no hemolytic activity. In addition, potide-G potently inhibited growth of a variety of bacterial (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Clavibacter michiganense subsp. michiganinse) and fungal (Candida albicans and Rhizoctonia solani) strains. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry revealed that the N-terminal sequence (residues from 1 to 11) of the protein is identical to that of potato proteinase inhibitor, a member of the Kunitz superfamily. And like other members of this class of protease inhibitor, potide-G may have a number of beneficial and therapeutic uses.
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Affiliation(s)
- Mi-Hyun Kim
- Research Center for Proteineous Materials, Chosun University, Kwangju 501-759, Republic of Korea
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65
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Jung HJ, Park Y, Hahm KS, Lee DG. Biological activity of Tat (47–58) peptide on human pathogenic fungi. Biochem Biophys Res Commun 2006; 345:222-8. [PMID: 16678135 DOI: 10.1016/j.bbrc.2006.04.059] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Accepted: 04/10/2006] [Indexed: 11/19/2022]
Abstract
Tat (47-58) peptide, a positively charged Arginine-rich peptide derived from HIV-1 regulatory protein Tat, is known for a peptidic delivery factor as a cell-penetrating peptide on mammalian cells. In this study, antifungal effect and its mode of action of Tat peptide were investigated on fungal cells. The results indicate that Tat peptide exhibits antifungal activity against pathogenic fungal cells without hemolytic effect on human erythrocytes. To understand the mechanism(s) of Tat peptide, the cellular distribution of the peptide was investigated. Tat peptide internalized in the fungal cells without any damage to cell membrane when examined using an artificial liposome (PC/cholesterol; 10:1, w/w). Moreover, flow cytometry analysis exhibited the uptake of Tat peptide by energy- and salt-independent pathway, and confocal scanning microscopy displayed that this peptide accumulated in the nucleus of fungal cells rapidly without any impediment by time or temperature, which generally influence on the viral infections. After penetration into the nuclear, the peptide affected the process of cell cycle of Candida albicans through the arrest at G1 phase.
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Affiliation(s)
- Hyun Jun Jung
- Department of Microbiology, College of Natural Sciences, Kyungpook National University, 1370 Sankyuk-dong, Puk-ku, Daegu 702-701, Republic of Korea
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THE EFFECTS OF BIOCIDES (ANTISEPTICS AND DISINFECTANTS) ON THE ENDOSPORES OF RHINOSPORIDIUM SEEBERI. Indian J Med Microbiol 2006. [DOI: 10.1016/s0255-0857(21)02404-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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67
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Lee K, Lee D, Park Y, Kang DI, Shin S, Hahm KS, Kim Y. Interactions between the plasma membrane and the antimicrobial peptide HP (2-20) and its analogues derived from Helicobacter pylori. Biochem J 2006; 394:105-14. [PMID: 16255716 PMCID: PMC1386008 DOI: 10.1042/bj20051574] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HP (2-20), a 19-residue peptide derived from the N-terminus of Helicobacter pylori ribosomal protein L1, has antimicrobial activity but is not cytotoxic to human erythrocytes. We synthesized several peptide analogues to investigate the effects of substitutions on structure and antimicrobial activity. Replacement of Gln16 and Asp18 with tryptophan [anal-3 (analogue-3)] caused a dramatic increase in lytic activities against bacteria and fungi. By contrast, a decrease in amphiphilicity caused by replacement of Phe5 or Leu11 with serine was accompanied by a reduction in antimicrobial activity. Analysis of the tertiary structures of the peptides in SDS micelles by NMR spectroscopy revealed that they have a well-defined a-helical structure. Among the analogues, anal-3 has the longest a-helix, from Val4 to Trp18. The enhanced hydrophobicity and increased a-helicity results in enhanced antimicrobial activity in anal-3 without an increase in haemolytic activity. Fluorescence experiments proved that the bacterial-cell selectivity of the anal-3 peptide is due to its high binding affinity for negatively charged phospholipids in bacterial cells. Results showing the effect of spin-labels on the NMR spectra indicated that the side chains in the hydrophobic phase of the amphiphilic a-helix are buried on the surface of the micelle and the tryptophan indole ring is anchored in the membrane surface. Because anal-3 shows high selectivity towards bacterial and fungal cells, it may provide an avenue for the development of new antibiotics.
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Affiliation(s)
- Kwang H. Lee
- *Department of Chemistry and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea
| | - Dong G. Lee
- †School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, Taegu 702-701, Korea
| | - Yoonkyung Park
- ‡Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Korea
| | - Dong-Il Kang
- *Department of Chemistry and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea
| | - Song Y. Shin
- ‡Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Korea
| | - Kyung-Soo Hahm
- ‡Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Korea
| | - Yangmee Kim
- *Department of Chemistry and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea
- To whom correspondence should be addressed (email )
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Arseculeratne SN, Atapattu DN, Wickramaratne K. Nature and significance of the electron-dense bodies of the endospores of rhinosporidium seeberi: their reactions with MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) and TMRE (tetramethyl-rhodamine ethyl ester). Med Mycol 2005; 43:261-73. [PMID: 16010853 DOI: 10.1080/13693780412331271063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The most conspicuous internal structures of the endospore of Rhinosporidium seeberi are the 10-16 spherical, 1.0-1.5-microm bodies that have been termed electron-dense bodies (EDB) or lipid bodies (LB); some authors have regarded them as nutritive stores of lipid or protein while others have regarded them as DNA-containing, ultimate generative units of R. seeberi. The literature is reviewed as supporting either view. We report, for the first time, (i) reactions of the endospores with the salt MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) and (ii) ultrastructural appearances; and suggest that both views on the nature of spherical bodies are valid (i.e. the endospore contains both EDB, and lipid or protein bodies). Well-marked reduction of the MTT with the production of deep-purple staining was seen in a proportion of the spherical bodies, probably the EDB, suggesting that they are actively metabolizing, viable elements with dehydrogenase activity, and that these bodies are the thick-walled electron-dense bodies described as EDB and visualized in the transmission electron microphotograph illustrated in this paper. The spherical bodies showed fluorescent labeling with acridine orange and with ethidium bromide supporting the idea that they contained nucleic acids. TMRE (tetramethyl rhodamine ethyl ester), a mitochondrion-specific dye, also labeled the intra-endosporial spherical bodies. Other bodies (LB) of a similar size that were MTT-non-reducing, electron lucent, and have no organized structure, are probably the lipid or protein containing, inert, nutritive storage bodies suggested by previous authors.
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Affiliation(s)
- S N Arseculeratne
- Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.
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69
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Jung HJ, Hwang IA, Sung WS, Kang H, Kang BS, Seu YB, Lee DG. Fungicidal effect of resveratrol on human infectious fungi. Arch Pharm Res 2005; 28:557-60. [PMID: 15974442 DOI: 10.1007/bf02977758] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Resveratrol, a phenolic antioxidant found in grapes, has been known to mediate various biological activities on the human body. In the present study, we tested the antifungal activity of resveratrol against human pathogenic fungi before carrying out further studies to elucidate the antifungal mechanism(s) of resveratrol. Resveratrol displayed potent antifungal activity against human pathogenic fungi at concentration levels of 10-20 microg/mL. Furthermore, time-kill curve exhibited fungicidal effect of resveratrol on C. albicans, but the compound had no hemolytic activity against human erythrocytes. The destruction of C. albicans cells by resveratrol was confirmed by scanning electron microscopy. These results suggest that resveratrol could be employed as a therapeutic agent to treat fungal infections of humans.
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Affiliation(s)
- Hyun Jun Jung
- Department of Microbiology, College of Natural Sciences, Kyungpook National University, Taegu 702-701, Korea
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Park Y, Choi BH, Kwak JS, Kang CW, Lim HT, Cheong HS, Hahm KS. Kunitz-type serine protease inhibitor from potato (Solanum tuberosum L. cv. Jopung). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:6491-6. [PMID: 16076139 DOI: 10.1021/jf0505123] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
An antifungal protein, AFP-J, was purified from tubers of the potato (Solanum tuberosum cv. L Jopung) by various chromatographic columns. AFP-J strongly inhibited yeast fungal strains, including Candida albicans, Trichosporon beigelii, and Saccharomyces cerevisiae, whereas it exhibited no activity against crop fungal pathogens. Automated Edman degradation determined the partial N-terminal sequence of AFP-J to be NH2-Leu-Pro-Ser-Asp-Ala-Thr-Leu-Val-Leu-Asp-Gln-Thr-Gly-Lys-G lu-Leu-Asp-Ala-Arg-Leu-. The partially sequence had 83% homology with a serine protease inhibitor belonging to the Kunitz family, and the protein inhibited chymotrypsin, pepsin, and trypsin. Mass spectrometry showed that its molecular mass was 13 500.5 Da. This protease inhibitor suppressed over 50% the proteolytic activity at 400 microg/mL. These results suggest that AFP-J is an excellent candidate as a lead compound for the development of novel antiinfective agents.
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Affiliation(s)
- Yoonkyung Park
- Research Center for Proteineous Materials, Department of Genetic Engineering, Chosun University, 375 Seosuk-Dong, Korea
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71
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Arseculeratne SN, Atapattu DN. The assessment of the viability of the endospores of Rhinosporidium seeberi with MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide). ACTA ACUST UNITED AC 2005; 108:1423-30. [PMID: 15757178 DOI: 10.1017/s0953756204001595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This report describes tests with Evan's Blue and MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) for the assessment of the viability of rhinosporidial endospores. MTT stained a proportion of the spherical bodies that we regard as the Electron Dense Bodies (EDBs), and the cytoplasm of freshly prepared endospores or ones that were stored at 4 degrees. Slow-freezing at -20 degrees C, exposure to 10% formalin, or 0.1% sodium azide of the endospores abolished MTT-staining in both sites. Evan's Blue stained the EDBs and cytoplasm of fresh endospores or those stored at 4 degrees, and of sodium azide-treated or frozen (-20 degrees)-thawed endospores. TMRE (tetramethyl-rhodamine ethyl ester) specifically labelled the spherical bodies, supporting the conclusion that these spherical bodies have a mitochondrial-like structure. TMRE-staining was however retained in endospores after their treatment with formalin, sodium azide and slow-freezing while MTT-staining was abolished in all these treated endospores. These results indicate that EvB and TMRE were capable of revealing the morphological integrity of endospores but failed to identify the metabolic inactivation of the endospores after treatment with formalin, sodium azide or slow-freezing. Only MTT was capable of identifying metabolically active endospores and hence their viability and could prove to be of value in standardizing models of infection.
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Affiliation(s)
- Sarath N Arseculeratne
- Department of Microbiology, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
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72
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Arseculeratne SN, Atapattu DN, Eriyagama NB. HUMAN ANTI-RHINOSPORIDIAL ANTIBODY DOES NOT CAUSE METABOLIC INACTIVATION OR MORPHOLOGICAL DAMAGE IN ENDOSPORES OF RHINOSPORIDIUM SEEBERI, IN VITRO. Indian J Med Microbiol 2005. [DOI: 10.1016/s0255-0857(21)02705-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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73
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Piao MS, Kim MR, Lee DG, Park Y, Hahm KS, Moon YH, Woo ER. Antioxidative constituents from Buddleia officinalis. Arch Pharm Res 2003; 26:453-7. [PMID: 12877553 DOI: 10.1007/bf02976861] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Four flavonoids (1-4), a phenylethyl glycoside (5), and a phenylpropanoid glycoside (6) were isolated from the flowers of Buddleia officinalis (Loganiaceae). Their structures were determined by chemical and spectral analysis. Among the isolated compounds, luteolin (1) and acteoside (6) exhibited the most potent antioxidative activity on the NBT superoxide scavenging assay. In addition, compounds 1-6 revealed weak antifungal activity, and no hemolytic activity.
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Affiliation(s)
- Mei Shan Piao
- College of Pharmacy, Chosun University, Gwangju 501-759, Korea
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74
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Lee DG, Kim HK, Kim SA, Park Y, Park SC, Jang SH, Hahm KS. Fungicidal effect of indolicidin and its interaction with phospholipid membranes. Biochem Biophys Res Commun 2003; 305:305-10. [PMID: 12745074 DOI: 10.1016/s0006-291x(03)00755-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The fungicidal effect and mechanism of a tryptophan-rich 13-mer peptide, indolicidin derived from granules of bovine neutrophils, were investigated. Indolicidin displayed a strong fungicidal activity against various fungi. In order to understand the fungicidal mechanism(s) of indolicidin, we examined the interaction of indolicidin with the pathogenic fungus Trichosporon beigelii. Fluorescence confocal microscopy and flow cytometry analysis revealed that indolicidin acted rapidly on the plasma membrane of the fungal cells in an energy-independent manner. This interaction is also dependent on the ionic environment. Furthermore, indolicidin caused significant morphological changes when tested for the membrane disrupting activity using liposomes (phosphatidylcholine/cholesterol; 10:1, w/w). The results suggest that indolicidin may exert its fungicidal activity by disrupting the structure of cell membranes, via direct interaction with the lipid bilayers, in a salt-dependent and energy-independent manner.
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Affiliation(s)
- Dong Gun Lee
- School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, 1370 Sankyuk-dong, Puk-ku, 702-701, Taegu, Republic of Korea.
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75
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Jahn B, Langfelder K, Schneider U, Schindel C, Brakhage AA. PKSP-dependent reduction of phagolysosome fusion and intracellular kill of Aspergillus fumigatus conidia by human monocyte-derived macrophages. Cell Microbiol 2002; 4:793-803. [PMID: 12464010 DOI: 10.1046/j.1462-5822.2002.00228.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previously, we described the isolation of an Aspergillus fumigatus mutant producing non-pigmented conidia, as a result of a defective polyketide synthase gene, pksP (polyketide synthase involved in pigment biosynthesis). The virulence of the pksP mutant was attenuated in a murine animal infection model and its conidia showed enhanced susceptibility towards damage by monocytes in vitro. Because macrophage-mediated killing is critical for host resistance to aspergillosis, the interaction of both grey-green wild-type conidia and white pksP mutant conidia with human monocyte-derived macrophages (MDM) was studied with respect to intracellular processing of ingested conidia. After phagocytosis, the percentage of wild-type conidia residing in an acidic environment was approximately fivefold lower than that observed for non-pigmented pksP mutant conidia. The phagolysosome formation, as assessed by co-localization of LAMP-1 and cathepsin D with ingested conidia, was significantly lower for wild-type conidia compared with pksP mutant conidia. Furthermore, the intracellular kill of pksP mutant conidia was significantly higher than of wild-type conidia, which was markedly increased by chloroquine, a known enhancer of phagolysosome fusion. Taken together, these findings suggest that the presence of a functional pksP gene in A. fumigatus conidia is associated with an inhibition of phagolysosome fusion in human MDM. These data show for the first time that a fungus has the capability to inhibit the fusion of the phagosome with the lysosome. This finding might help explain the attenuated virulence of pksP mutant strains in a murine animal model and provides a conceptual frame to understand the virulence of A. fumigatus.
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Affiliation(s)
- Bernhard Jahn
- Institut für Medizinische Mikrobiologie und Hygiene, Johannes Gutenberg-Universität Mainz, Hochhaus am Augustusplatz, D-55101 Mainz, Germany.
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76
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Yamaguchi H, Uchida K, Nagino K, Matsunaga T. Usefulness of a colorimetric method for testing antifungal drug susceptibilities of Aspergillus species to voriconazole. J Infect Chemother 2002; 8:374-7. [PMID: 12525904 DOI: 10.1007/s10156-002-0201-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The usefulness of a colorimetric method using Alamar Blue (Alamar Blue method) for susceptibility testing of Aspergillus species to voriconazole and three existing antifungal agents, itraconazole (ITCZ), flucytosine (5-FC), and amphotericin B (AMPH-B), was studied using four ATCC strains of three species, including two strains of A. fumigatus and one each of A. flavus and A. niger. For comparison, the broth microdilution method for antifungal susceptibility testing of filamentous fungi proposed by the National Committee for Clinical Laboratory Standards (NCCLS method M38-P) was also used. Minimum inhibitory concentration (MIC) endpoints were read spectrophotometrically for the Alamar Blue method and visually for the NCCLS method after 46-50 h. Like the NCCLS method, Alamar Blue produced highly reproducible results for all the drugs and strains tested; most MIC values obtained by nine tests were within the range of 2 twofold dilutions for each strain. Voriconazole and ITCZ susceptibility testing with the Alamar Blue method and the NCCLS method yielded comparable results in 94% of the tests, meaning that the endpoints obtained were identical or differed by no more than 2 twofold dilutions. On the other hand, susceptibility testing for 5-FC and AMPH-B yielded scores of 25% and 64%, respectively. Our study suggests the potential value of the Alamar Blue method as a convenient alternative to the NCCLS M38-P method for routine testing of Aspergillus species susceptibility to at least voriconazole and ITCZ.
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Affiliation(s)
- Hideyo Yamaguchi
- Research Institute of Medical Mycology, Teikyo University, Tokyo, Japan
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77
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Marcil A, Harcus D, Thomas DY, Whiteway M. Candida albicans killing by RAW 264.7 mouse macrophage cells: effects of Candida genotype, infection ratios, and gamma interferon treatment. Infect Immun 2002; 70:6319-29. [PMID: 12379711 PMCID: PMC130362 DOI: 10.1128/iai.70.11.6319-6329.2002] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phagocytic cells such as neutrophils and macrophages are potential components of the immune defense that protects mammals against Candida albicans infection. We have tested the interaction between the mouse macrophage cell line RAW 264.7 and a variety of mutant strains of C. albicans. We used an end point dilution assay to monitor the killing of C. albicans at low multiplicities of infection (MOIs). Several mutants that show reduced virulence in mouse systemic-infection models show reduced colony formation in the presence of macrophage cells. To permit analysis of the macrophage-Candida interaction at higher MOIs, we introduced a luciferase reporter gene into wild-type and mutant Candida cells and used loss of the luminescence signal to quantify proliferation. This assay gave results similar to those for the end point dilution assay. Activation of the macrophages with mouse gamma interferon did not enhance anti-Candida activity. Continued coculture of the Candida and macrophage cells eventually led to death of the macrophages, but for the RAW 264.7 cell line this was not due to apoptotic pathways involving caspase-8 or -9 activation. In general Candida cells defective in the formation of hyphae were both less virulent in animal models and more sensitive to macrophage engulfment and growth inhibition. However the nonvirulent, hypha-defective cla4 mutant line was considerably more resistant to macrophage-mediated inhibition than the wild-type strain. Thus although mutants sensitive to engulfment are typically less virulent in systemic-infection models, sensitivity to phagocytic macrophage cells is not the unique determinant of C. albicans virulence.
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Affiliation(s)
- A Marcil
- Genetics Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec H4P 2R2, USA.
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78
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Gun Lee D, Park Y, Il Kim P, Gwang Jeong H, Woo ER, Hahm KS. Influence on the plasma membrane of Candida albicans by HP (2–9)–magainin 2 (1–12) hybrid peptide. Biochem Biophys Res Commun 2002. [DOI: 10.1016/s0006-291x(02)02230-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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79
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Lee DG, Kim PI, Park Y, Jang SH, Park SC, Woo ER, Hahm KS. HP (2-20) derived from the amino terminal region of helicobacterpylori ribosomal protein L1 exerts its antifungal effects by damaging the plasma membranes of Candida albicans. J Pept Sci 2002; 8:453-60. [PMID: 12212808 DOI: 10.1002/psc.405] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The fungicidal effects of the peptide HP (2-20). derived from the N-terminal sequence of Helicobacter pylori ribosomal protein L1 (RPL1). have been investigated. HP (2-20) displays a strong fungicidal activity against various fungi, without haemolytic activity against human erythrocyte cells, and the fungicidal activity is inhibited by Ca2+ and Mg2+ ions. In order to investigate the fungicidal mechanism(s) of HP (2-20). the amount of intracellular trehalose was measured in C. albicans. It was found that the amounts of intracellular trehalose were decreased when HP (2-20) was used. The action of the peptide against fungal cell membranes was further examined by the potassium-release test; HP (2-20) was found to increase the amount of K+ released from the cells. Furthermore, HP (2-20) caused significant morphological changes, as shown by scanning electron microscopy, and by testing the membrane disrupting activity using liposomes (phosphatidyl choline/cholesterol; 10: 1, w/w). Our results suggest that HP (2-20) may exert its antifungal activity by disrupting the structure of cell membranes, via pore formation or direct interaction with the lipid bilayers.
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Affiliation(s)
- Dong Gun Lee
- Research Center for Proteineous Materials, Chosun University, Kwangju, Korea
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80
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Lee DG, Kim HN, Park Y, Kim HK, Choi BH, Choi CH, Hahm KS. Design of novel analogue peptides with potent antibiotic activity based on the antimicrobial peptide, HP (2-20), derived from N-terminus of Helicobacter pylori ribosomal protein L1. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1598:185-94. [PMID: 12147359 DOI: 10.1016/s0167-4838(02)00373-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antimicrobial sequence derived from the N-terminus of Helicobacter pylori ribosomal protein L1 (RPL1). In order to develop novel antibiotic peptides useful as therapeutic agents, potent antibiotic activities against bacteria, fungi and cancer cells without a cytotoxic effect are essential. To this end, several analogues with amino acid substitutions were designed to increase or decrease only the net hydrophobicity. In particular, the substitution of Trp for the hydrophobic amino acids, Gln and Asp at positions 17 and 19 of HP (2-20) (Anal 3), caused a dramatic increase in antibiotic activity without a hemolytic effect. In contrast, the decrease of hydrophobicity brought about by substituting Ser for Leu and Phe at positions 12 and 19 of HP (2-20), respectively (Anal 4, Anal 5), did not have a significant effect on the antibiotic activity. The antibiotic effects of these synthetic peptides were further investigated by treating prepared protoplasts of Candida albicans and conducting an artificial liposomal vesicle (PC/PS; 3:1, w/w) disrupting activity test. The results demonstrated that the Anal 3 prevented the regeneration of fungal cell walls and induced an enhanced release of fluorescent dye (carboxyfluorescein) trapped in the artificial membrane vesicles to a greater degree than HP (2-20). The potassium-release test conducted on C. albicans indicated that Anal 3 induced greater amounts of potassium ion to be released than the parent peptide, HP (2-20) did. These results indicated that the hydrophobic region of peptides is prerequisite for its effective antibiotic activity and may facilitate easy penetration of the lipid bilayers of the cell membrane.
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Affiliation(s)
- Dong Gun Lee
- Research Center for Proteineous Materials, Chosun University, 375 Seosuk-Dong, Dong-Ku, Kwangju, South Korea
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81
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Lee DG, Kim PI, Park Y, Park SC, Woo ER, Hahm KS. Antifungal mechanism of SMAP-29 (1-18) isolated from sheep myeloid mRNA against Trichosporon beigelii. Biochem Biophys Res Commun 2002; 295:591-6. [PMID: 12099679 DOI: 10.1016/s0006-291x(02)00717-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The antifungal activity and mechanism of SMAP-29 (1-18) (SMAP-29), a cathelicidin-derived antimicrobial peptide deduced from N-terminal sequence of sheep myeloid mRNA, were investigated. SMAP-29 displayed a strong antifungal activity against various fungi. To understand the antifungal mechanism(s) of SMAP-29, we examined the interaction of SMAP-29 with the pathogenic fungus Trichosporon beigelii. Confocal microscopy showed that SMAP-29 was localized in the plasma membrane. The antifungal effects of SMAP-29 were further confirmed by using 1,6-diphenyl-1,3,5-hexatriene (DPH) as a plasma membrane probe. Flow cytometric analysis revealed that SMAP-29 acted in an energy-dependent manner. This interaction is also dependent on the ionic environment. Furthermore, SMAP-29 caused significant morphological changes when testing the membrane disrupting activity using liposomes (phosphatidylcholine/cholesterol; 10:1, w/w), as shown by scanning electron microscopy. The results suggest that SMAP-29 may exert its antifungal activity by disrupting the structure of cell membranes, via direct interaction with the lipid bilayers and irregularly disrupted fungal membranes in an energy- and salt-dependent manner.
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Affiliation(s)
- Dong Gun Lee
- Research Center for Proteineous Materials (RCPM), Chosun University, 375 Seosuk-Dong, Dong-Ku, Kwangju 501-759, Republic of Korea
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82
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Lee DG, Kim PI, Park Y, Woo ER, Choi JS, Choi CH, Hahm KS. Design of novel peptide analogs with potent fungicidal activity, based on PMAP-23 antimicrobial peptide isolated from porcine myeloid. Biochem Biophys Res Commun 2002; 293:231-8. [PMID: 12054589 DOI: 10.1016/s0006-291x(02)00222-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PMAP-23 is a 23-mer peptide derived from porcine myeloid. To develop novel antifungal peptides useful as therapeutic drugs, it would require a strong fungicidal activity against pathogenic fungal cells. To this goal, several analogs, with amino acid substitutions, were designed to increase the net hydrophobicity by Trp (W)-substitution at positions 10, 13, or 14 at the hydrophilic face of PMAP-23 without changing the hydrophobic helical face. The Trp (W)-substitution (P6) showed an enhanced fungicidal and antitumor activities, with the fungicidal activity inhibited by salts and the respiratory inhibitor, NaN(3). The results suggested that the increase of hydrophobicity of the peptides correlated with fungicidal activity. The fungicidal effects of analog peptides were further investigated using 1,6-diphenyl-1,3,5-hexatriene (DPH) as a membrane probe. In Candida albicans, the analog peptide (P6) exerted its fungicidal effect on the blastoconidia in 20% fetal bovine serum by disrupting the mycelial forms. Furthermore, P6 caused significant morphological changes, and these facts suggested that the fungicidal function of the novel analog peptide (P6) was by damaging the fungal cell membranes. Thus, this peptide may provide a useful template for designing novel antifungal peptides useful for the treatment of infectious diseases.
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Affiliation(s)
- Dong Gun Lee
- Research Center for Proteineous Materials, Chosun University, 375 Seosuk-Dong, Dong-Ku, Kwangju 501-759, Republic of Korea
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83
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Lee DG, Park Y, Kim HN, Kim HK, Kim PI, Choi BH, Hahm KS. Antifungal mechanism of an antimicrobial peptide, HP (2--20), derived from N-terminus of Helicobacter pylori ribosomal protein L1 against Candida albicans. Biochem Biophys Res Commun 2002; 291:1006-13. [PMID: 11866466 DOI: 10.1006/bbrc.2002.6548] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antifungal activity and mechanism of HP (2-20), a peptide derived from the N-terminus sequence of Helicobacter pylori Ribosomal Protein L1 were investigated. HP (2--20) displayed a strong antifungal activity against various fungi, and the antifungal activity was inhibited by Ca(2+) and Mg(2+) ions. In order to investigate the antifungal mechanism(s) of HP (2-20), fluorescence activated flow cytometry was performed. As determined by propidium iodide staining, Candida albicans treated with HP (2-20) showed a higher fluorescence intensity than untreated cells and was similar to melittin-treated cells. The effect on fungal cell membranes was examined by investigating the change in membrane dynamics of C. albicans using 1,6-diphenyl-1,3,5-hexatriene as a membrane probe and by testing the membrane disrupting activity using liposome (PC/PS; 3:1, w/w) and by treating protoplasts of C. albicans with the peptide. The action of peptide against fungal cell membrane was further examined by the potassium-release test, and HP (2-20) was able to increase the amount of K(+) released from the cells. The result suggests that HP (2-20) may exert its antifungal activity by disrupting the structure of cell membrane via pore formation or directly interacts with the lipid bilayers in a salt-dependent manner.
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Affiliation(s)
- Dong Gun Lee
- Research Center for Proteineous Materials, Chosun University, 375 Seosuk-Dong, Dong-Ku, Kwangju 501-759, Korea
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84
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Pfaller MA, Yu WL. Antifungal susceptibility testing. New technology and clinical applications. Infect Dis Clin North Am 2001; 15:1227-61. [PMID: 11780273 DOI: 10.1016/s0891-5520(05)70192-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The state of the art for susceptibility testing of yeasts is comparable with that of bacteria. Standardized methods for performing antifungal susceptibility testing are reproducible, accurate, and available in clinical laboratories. The development of quality control limits and interpretive criteria for a limited number of antifungal agents provides a basis for the application of this testing in the clinical laboratory. A proficiency testing program is available as a quality assurance measure for laboratories and has documented steady improvement among laboratories using the NCCLS method. As with antibacterial agents, surveillance programs are now in place using reference quality testing methods to monitor antifungal resistance trends on a global scale. It is clear that antifungal susceptibility testing can predict outcome in several clinical situations. Susceptibility testing is most helpful in dealing with infection caused by non-albicans species of Candida, and susceptibility testing of azoles is increasingly important in the management of candidiasis in critically ill patients. Susceptibility testing also has been standardized for filamentous fungi that cause invasive infections. Studies are ongoing to further refine this approach and evaluate the in vivo correlation with the in vitro data for molds. Future efforts must be directed toward establishing and validating interpretive break-points for licensed antifungals such as amphotericin B, and for new antifungals that are not yet licensed. Finally, procedures must be optimized for testing non-Candida yeasts (e.g., C. neoformans) and molds.
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Affiliation(s)
- M A Pfaller
- Medical Microbiology Division, Department of Pathology, University of Iowa College of Medicine, Iowa City, Iowa, USA.
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85
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Meletiadis J, Mouton JW, Meis JF, Bouman BA, Donnelly PJ, Verweij PE. Comparison of spectrophotometric and visual readings of NCCLS method and evaluation of a colorimetric method based on reduction of a soluble tetrazolium salt, 2,3-bis [2-methoxy-4-nitro-5-[(sulfenylamino) carbonyl]-2H-tetrazolium-hydroxide], for antifungal susceptibility testing of Aspergillus species. J Clin Microbiol 2001; 39:4256-63. [PMID: 11724829 PMCID: PMC88533 DOI: 10.1128/jcm.39.12.4256-4263.2001] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The susceptibilities of 25 clinical isolates of various Aspergillus species (Aspergillus fumigatus, A. flavus, A. terreus, A. ustus, and A. nidulans) to itraconazole (ITC) and amphotericin B (AMB) were determined using the standard proposed by NCCLS for antifungal susceptibility testing of[filamentous fungi, a modification of this method using spectrophotometric readings, and a colorimetric method using the tetrazolium salt 2,3-bis [2-methoxy-4-nitro-5-[(sulfenylamino) carbonyl]-2H-tetrazolium-hydroxide] (XTT). Five MIC end points for ITC (MIC-0, no visible growth or <or=5% the growth control value [GC]; MIC-1, slight growth or 6 to 25% the GC; MIC-2, prominent reduction in growth or 26 to 50% the GC; MIC-3, slight reduction in growth or 51 to 75% the GC; and MIC-4, no reduction in growth or 76 to 100% the GC) and one for AMB (MIC-0) were determined visually by four observers and spectrophotometrically. The intraexperimental (between the observers) and interexperimental (between the experiments) levels of agreement of the NCCLS and XTT methods exceeded 95% for MIC-0 of AMB and MIC-0 and MIC-1 of ITC. The MIC-2 of ITC showed lower reproducibility, although spectrophotometric reading and/or incubation for 48 h increased the interexperimental reproducibility from 85 to >93%. Between visual and spectrophotometric readings, high levels of agreement were found for AMB (approximately 97%) and MIC-1 (approximately 92%) and MIC-2 (approximately 88%) of ITC. Poor agreement was found for MIC-0 of ITC (51% after 24 h), since the spectrophotometric readings resulted in higher MIC-0 values than the visual readings. The agreement was increased to 98% by shifting the threshold level of MIC-0 from 5 to 10% relative optical density and by establishing an optical density of greater than 0.1 for the GC as the validation criterion. No statistically significant differences were found between the NCCLS method and the XTT method, with the levels of agreement exceeding 97% for MIC-0 of AMB and 83% for MIC-0, MIC-1, and MIC-2 of ITC. The XTT method and spectrophotometric readings can increase the sensitivity and the precision, respectively, of in vitro susceptibility testing of Aspergillus species.
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Affiliation(s)
- J Meletiadis
- Department of Medical Microbiology, University Medical Center Nijmegen, Nijmegen, The Netherlands
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86
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Meletiadis J, Mouton JW, Meis JF, Bouman BA, Donnelly JP, Verweij PE. Colorimetric assay for antifungal susceptibility testing of Aspergillus species. J Clin Microbiol 2001; 39:3402-8. [PMID: 11526191 PMCID: PMC88359 DOI: 10.1128/jcm.39.9.3402-3408.2001] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A colorimetric assay for antifungal susceptibility testing of Aspergillus species (Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Aspergillus nidulans, and Aspergillus ustus) is described based on the reduction of the tetrazolium salt 2,3-bis(2-methoxy-4-nitro-5-[(sulphenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) in the presence of menadione as an electron-coupling agent. The combination of 200 microg of XTT/ml with 25 microM menadione resulted in a high production of formazan within 2 h of exposure, allowing the detection of hyphae formed by low inocula of 10(2) CFU/ml after 24 h of incubation. Under these settings, the formazan production correlated linearly with the fungal biomass and less-variable concentration effect curves for amphotericin B and itraconazole were obtained.
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Affiliation(s)
- J Meletiadis
- Department of Medical Microbiology, University Medical Center Nijmegen, Nijmegen, The Netherlands
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87
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Lee DG, Kim DH, Park Y, Kim HK, Kim HN, Shin YK, Choi CH, Hahm KS. Fungicidal effect of antimicrobial peptide, PMAP-23, isolated from porcine myeloid against Candida albicans. Biochem Biophys Res Commun 2001; 282:570-4. [PMID: 11401498 DOI: 10.1006/bbrc.2001.4602] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antifungal activity and mechanism of a 23-mer peptide, PMAP-23, derived from pig myeloid was investigated. PMAP-23 displayed strong antifungal activity against yeast and mold. To investigate the antifungal mechanism of PMAP-23, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed. Candida albicans treated with PMAP-23 showed higher fluorescence intensity by propidium iodide(PI) staining, which was similar to that of Melittin than untreated cells. Confocal microscopy showed that the peptide was located in the plasma membrane. The action of peptides against fungal cell membranes was examined by treating prepared protoplasts of C. albicans with the peptide and lipid vesicle titration test. The result showed that the peptide prevented the regeneration of fungal cell walls and induced release of the fluorescent dye trapped in the artificial membrane vesicles, indicating that the peptide exerts its antifungal activity by acting on the plasma lipid membrane.
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Affiliation(s)
- D G Lee
- Research Center for Proteineous Materials, Department of Pharmacology, School of Medicine, Chosun University, 375 Seosuk-Dong, Kwangju, Dong-Ku, 501-759, Korea
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88
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Espinel-Ingroff A. Germinated and nongerminated conidial suspensions for testing of susceptibilities of Aspergillus spp. to amphotericin B, itraconazole, posaconazole, ravuconazole, and voriconazole. Antimicrob Agents Chemother 2001; 45:605-7. [PMID: 11158763 PMCID: PMC90335 DOI: 10.1128/aac.45.2.605-607.2001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of germinated and nongerminated conidia of Aspergillus spp. on the fungistatic (National Committee for Clinical Laboratory Standards document M38-P) and fungicidal activities (MICs and minimal fungicidal concentrations [MFCs] respectively) of amphotericin B, itraconazole, posaconazole (SCH56592), ravuconazole (BMS-207147), and voriconazole was evaluated. MFCs were the lowest drug dilutions that showed fewer than three colonies (99.9% killing). Overall, the MICs (0.12 to 4 microg/ml) and MFCs (0.5 to >8 microg/ml) of all of the agents tested with both inocula were the same or within 2 dilutions for the 72 isolates. Therefore, MICs and MFCs can be obtained with convenient and standardized nongerminated conidia.
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Affiliation(s)
- A Espinel-Ingroff
- Medical College of Virginia/Virginia Commonwealth University, Richmond, Virginia 23298, USA.
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89
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Ertl P, Robello E, Battaglini F, Mikkelsen SR. Rapid antibiotic susceptibility testing via electrochemical measurement of ferricyanide reduction by Escherichia coli and Clostridium sporogenes. Anal Chem 2000; 72:4957-64. [PMID: 11055715 DOI: 10.1021/ac0003596] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrochemical measurement of respiratory chain activity allows rapid and reliable screening for antibiotic susceptibility in microorganisms. Chronoamperometry and chronocoulometry of suspensions of aerobically cultivated E. coli combined with the non-native oxidant potassium hexacyanoferrate(III) (ferricyanide) yield signals for reoxidation of the reduction product ferrocyanide that are much smaller if the E. coli has been incubated briefly with an effective antibiotic compound. Chronocoulometric results, obtained following 20-min incubation with antibiotic and 2-min measurement in assay buffer containing 50 mM ferricyanide and 10 mM succinate, at +0.50 V vs Ag/AgCl at a Pt working electrode, were compared with traditional disk diffusion susceptibility testing, which requires overnight incubation on agar plates; the results show significantly lower accumulation of ferrocyanide in all cases in which growth inhibition was observed in the disk diffusion assay. A range of antibiotic compounds (13) were examined that possess different mechanisms of action. Quantitative determination of IC50 values for penicillin G and chloramphenicol yielded values that were 100-fold higher than those obtained by standard turbidity methods after 10-h incubation; this is likely a result of the very brief (10 min) exposure time to the antibiotics. Addition of 5 microM 2,6-dichlorophenolindophenol, a hydrophobic electron-transfer mediator, to the assay mixture allowed susceptibility testing of a Gram-positive obligate anaerobe, Clostridium sporogenes. This rapid new assay will facilitate clinical susceptibility testing, allowing appropriate treatment virtually as soon as a clinical isolate can be obtained.
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Affiliation(s)
- P Ertl
- Department of Chemistry, University of Waterloo, Ontario, Canada
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90
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Meletiadis J, Meis JF, Mouton JW, Donnelly JP, Verweij PE. Comparison of NCCLS and 3-(4,5-dimethyl-2-Thiazyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) methods of in vitro susceptibility testing of filamentous fungi and development of a new simplified method. J Clin Microbiol 2000; 38:2949-54. [PMID: 10921957 PMCID: PMC87156 DOI: 10.1128/jcm.38.8.2949-2954.2000] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The susceptibility of 30 clinical isolates belonging to six different species of filamentous fungi (Aspergillus fumigatus, Aspergillus flavus, Scedosporium prolificans, Scedosporium apiospermum, Fusarium solani, and Fusarium oxysporum) was tested against six antifungal drugs (miconazole, voriconazole, itraconazole, UR9825, terbinafine, and amphotericin B) with the microdilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) (M38-P). The MICs were compared with the MICs obtained by a colorimetric method measuring the reduction of the dye 3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan by viable fungi. The levels of agreement between the two methods were 96 and 92% for MIC-0 (clear wells) and MIC-1 (75% growth reduction), respectively. The levels of agreement were always higher for Aspergillus spp. (97% +/- 2.5%), followed by Scedosporium spp. (87% +/- 10.3%) and Fusarium spp. (78% +/- 7.8%). The NCCLS method was more reproducible than the MTT method: 98 versus 95% for MIC-0 and 97 versus 90% for MIC-1. However, the percentage of hyphal growth as determined visually by the NCCLS method showed several discrepancies when they were compared with the percentages of MTT reduction. A new simplified assay that incorporates the dye MTT with the initial inoculum and in which the fungi are incubated with the dye for 48 h or more was developed, showing comparable levels of agreement and reproducibility with the other two methods. Furthermore, the new assay was easier to perform and more sensitive than the MTT method.
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Affiliation(s)
- J Meletiadis
- Departments of Medical Microbiology, University Medical Center Nijmegen, Nijmegen, The Netherlands.
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91
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Brown AM, Dolan JW, Willi SM, Garvey WT, Argyropoulos G. Endogenous mutations in human uncoupling protein 3 alter its functional properties. FEBS Lett 1999; 464:189-93. [PMID: 10618503 DOI: 10.1016/s0014-5793(99)01708-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human uncoupling protein (UCP3) is a mitochondrial transmembrane carrier that uncouples oxidative phosphorylation and is a candidate gene for obesity. Expression of native human UCP3 mutations in yeast showed complete loss (R70W), significant reduction (R143X), or no effect (V102I and IVS6+1G > A) on the uncoupling activity of UCP3. It is concluded that certain mutations in UCP3 alter its functional impact on membrane potential (deltaphi), possibly conferring susceptibility to develop metabolic diseases.
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Affiliation(s)
- A M Brown
- Department of Medicine, Division of Endocrinology, Medical University of South Carolina, 114 Doughty Street, Charleston, SC, USA
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92
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Arikan S, Lozano-Chiu M, Paetznick V, Nangia S, Rex JH. Microdilution susceptibility testing of amphotericin B, itraconazole, and voriconazole against clinical isolates of Aspergillus and Fusarium species. J Clin Microbiol 1999; 37:3946-51. [PMID: 10565912 PMCID: PMC85852 DOI: 10.1128/jcm.37.12.3946-3951.1999] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the activities of amphotericin B, itraconazole, and voriconazole against clinical Aspergillus (n = 82) and Fusarium (n = 22) isolates by a microdilution method adopted from the National Committee for Clinical Laboratory Standards (NCCLS-M27A). RPMI 1640 (RPMI), RPMI 1640 supplemented to 2% glucose (RPMI-2), and antibiotic medium 3 supplemented to 2% glucose (AM3) were used as test media. MICs were determined after 24, 48, and 72 h. A narrow range of amphotericin B MICs was observed for Aspergillus isolates, with minor variations among species. MICs for Fusarium isolates were higher than those for Aspergillus isolates. MICs of itraconazole were prominently high for two previously defined itraconazole-resistant Aspergillus fumigatus isolates and Fusarium solani. Voriconazole showed good in vitro activity against itraconazole-resistant isolates, but the MICs of voriconazole for F. solani were high. RPMI was the most efficient medium for detection of itraconazole-resistant isolates, followed by RPMI-2. While the significance remains unclear, AM3 lowered the MICs, particularly those of amphotericin B.
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Affiliation(s)
- S Arikan
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA.
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93
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Dannaoui E, Persat F, Monier MF, Borel E, Piens MA, Picot S. Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp. Can J Microbiol 1999. [DOI: 10.1139/w99-075] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.
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94
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Gruber A, Speth C, Lukasser-Vogl E, Zangerle R, Borg-von Zepelin M, Dierich MP, Würzner R. Human immunodeficiency virus type 1 protease inhibitor attenuates Candida albicans virulence properties in vitro. IMMUNOPHARMACOLOGY 1999; 41:227-34. [PMID: 10428651 DOI: 10.1016/s0162-3109(99)00035-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The putative virulence factor secreted aspartyl proteinase (SAP) of Candida albicans and the human immunodeficiency virus type 1 (HIV-1) protease both belong to the aspartyl proteinase family. The present study demonstrates that the HIV-1 protease inhibitor Indinavir is a weak but specific inhibitor of SAP. In addition, Indinavir reduces the amount of cell bound as well as released SAP antigen from C. albicans. Furthermore, viability and growth of C. albicans are markedly reduced by Indinavir. These findings indicate that HIV-1 protease inhibitors may possess antifungal activity and we speculate that in vivo SAP inhibition may add to the resolution of mucosal candidiasis in HIV-1 infected subjects.
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Affiliation(s)
- A Gruber
- Ludwig Boltzmann-Institut für AIDS-Forschung and Institut für Hygiene, University of Innsbruck, Austria.
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95
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Herreros E, Martinez CM, Almela MJ, Marriott MS, De Las Heras FG, Gargallo-Viola D. Sordarins: in vitro activities of new antifungal derivatives against pathogenic yeasts, Pneumocystis carinii, and filamentous fungi. Antimicrob Agents Chemother 1998; 42:2863-9. [PMID: 9797217 PMCID: PMC105957 DOI: 10.1128/aac.42.11.2863] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
GM 193663, GM 211676, GM 222712, and GM 237354 are new semisynthetic derivatives of the sordarin class. The in vitro antifungal activities of GM 193663, GM 211676, GM 222712, and GM 237354 against 111 clinical yeast isolates of Candida albicans, Candida kefyr, Candida glabrata, Candida parapsilosis, Candida krusei, and Cryptococcus neoformans were compared. The in vitro activities of some of these compounds against Pneumocystis carinii, 20 isolates each of Aspergillus fumigatus and Aspergillus flavus, and 30 isolates of emerging less-common mold pathogens and dermatophytes were also compared. The MICs of GM 193663, GM 211676, GM 222712, and GM 237354 at which 90% of the isolates were inhibited (MIC90s) were 0.03, 0.03, 0.004, and 0.015 microg/ml, respectively, for C. albicans, including strains with decreased susceptibility to fluconazole; 0.5, 0.5, 0.06, and 0.12 microg/ml, respectively, for C. tropicalis; and 0.004, 0.015, 0.008, and 0.03 microg/ml, respectively, for C. kefyr. GM 222712 and GM 237354 were the most active compounds against C. glabrata, C. parapsilosis, and Cryptococcus neoformans. Against C. glabrata and C. parapsilosis, the MIC90s of GM 222712 and GM 237354 were 0.5 and 4 microg/ml and 1 and 16 microg/ml, respectively. The MIC90s of GM 222712 and GM 237354 against Cryptococcus neoformans were 0.5 and 0.25 microg/ml, respectively. GM 193663, GM 211676, GM 222712, and GM 237354 were extremely active against P. carinii. The efficacies of sordarin derivatives against this organism were determined by measuring the inhibition of the uptake and incorporation of radiolabelled methionine into newly synthesized proteins. All compounds tested showed 50% inhibitory concentrations of <0.008 microg/ml. Against A. flavus and A. fumigatus, the MIC90s of GM 222712 and GM 237354 were 1 and 32 microg/ml and 32 and >64 microg/ml, respectively. In addition, GM 237354 was tested against the most important emerging fungal pathogens which affect immunocompromised patients. Cladosporium carrioni, Pseudallescheria boydii, and the yeast-like fungi Blastoschizomyces capitatus and Geotrichum clavatum were the most susceptible of the fungi to GM 237354, with MICs ranging from </=0.25 to 2 microg/ml. The MICs of GM 237354 against Trichosporon beigelii and the zygomycetes Absidia corymbifera, Cunninghamella bertholletiae, and Rhizopus arrhizus ranged from </=0.25 to 8 microg/ml. Against dermatophytes, GM 237354 MICs were >/=2 microg/ml. In summary, we concluded that some sordarin derivatives, such as GM 222712 and GM 237354, showed excellent in vitro activities against a wide range of pathogenic fungi, including Candida spp., Cryptococcus neoformans, P. carinii, and some filamentous fungi and emerging invasive fungal pathogens.
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Affiliation(s)
- E Herreros
- Glaxo Wellcome S.A., 28760 Tres Cantos, Madrid, Spain
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96
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Jahn B, Rampp A, Dick C, Jahn A, Palmer M, Bhakdi S. Accumulation of amphotericin B in human macrophages enhances activity against Aspergillus fumigatus conidia: quantification of conidial kill at the single-cell level. Antimicrob Agents Chemother 1998; 42:2569-75. [PMID: 9756757 PMCID: PMC105899 DOI: 10.1128/aac.42.10.2569] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A cytofluorometric assay that allowed assessment of damage to phagocytosed Aspergillus fumigatus conidia at the single-cell level was developed. After ingestion by monocyte-derived macrophages (MDMs), conidia were reisolated by treatment of the cells with streptolysin O, a pore-forming toxin with lytic properties on mammalian cells but not on fungi. The counts obtained by staining of damaged conidia with propidium iodide and quantification by cytofluorometry correlated with colony counts. By the use of this method, we demonstrate that MDMs differentiated in vitro by low-dose granulocyte-macrophage colony-stimulating factor and gamma interferon have only a limited capacity to damage Aspergillus conidia in vitro. The killing rate 12 h after phagocytosis was found to be only 10 to 15%. However, intracellular loading of the phagocytes with amphotericin B (AmB) dose dependently enhanced the anticonidial activity. Preincubation of macrophages with only 1 microg of AmB per ml resulted in an uptake of 18 fg of AmB/cell, leading to killing rates of 50 to 60%. The experimental protocol provides a new tool for the rapid quantification of anticonidial activity against A. fumigatus in vitro. Intracellular accumulation of AmB may represent an important factor underlying the efficacy of this antifungal drug in the prophylaxis and treatment of Aspergillus infections.
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Affiliation(s)
- B Jahn
- Institute of Medical Microbiology and Hygiene, Johannes Gutenberg University, Mainz, Mainz, Germany.
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97
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Jahn B, Koch A, Schmidt A, Wanner G, Gehringer H, Bhakdi S, Brakhage AA. Isolation and characterization of a pigmentless-conidium mutant of Aspergillus fumigatus with altered conidial surface and reduced virulence. Infect Immun 1997; 65:5110-7. [PMID: 9393803 PMCID: PMC175736 DOI: 10.1128/iai.65.12.5110-5117.1997] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Aspergillus fumigatus is an important pathogen of immunocompromised hosts, causing pneumonia and invasive disseminated disease with high mortality. The factors contributing to the predominance of A. fumigatus as an opportunistic pathogen are largely unknown. Since the survival of conidia in the host is a prerequisite for establishing disease, we have been attempting to identify factors which are associated with conidia and, simultaneously, important for infection. Therefore, an A. fumigatus mutant strain (white [W]) lacking conidial pigmentation was isolated. Scanning electron microscopy revealed that conidia of the W mutant also differed in their surface morphology from those of the wild type (WT). Mutant (W) and WT conidia were compared with respect to their capacities to stimulate an oxidative response in human phagocytes, their intracellular survival in human monocytes, and virulence in a murine animal model. Luminol-dependent chemiluminescence was 10-fold higher when human neutrophils or monocytes were challenged with W conidia compared with WT conidia. Furthermore, mutant conidia were more susceptible to killing by oxidants in vitro and were more efficiently damaged by human monocytes in vitro than WT conidia. In a murine animal model, the W mutant strain showed reduced virulence compared with the WT. A reversion analysis of the W mutant demonstrated that all phenotypes associated with the W mutant, i.e., altered conidial surface, amount of reactive oxygen species release, susceptibility to hydrogen peroxide, and reduced virulence in an murine animal model, coreverted in revertants which had regained the ability to produce green spores. This finding strongly suggests that the A. fumigatus mutant described here carries a single mutation which caused all of the observed phenotypes. Our results suggest that the conidium pigment or a structural feature related to it contributes to fungal resistance against host defense mechanisms in A. fumigatus infections.
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Affiliation(s)
- B Jahn
- Institut für Medizinische Mikrobiologie der Johannes Gutenberg-Universität, Mainz, Federal Republic of Germany.
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98
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Clancy CJ, Nguyen MH. Comparison of a photometric method with standardized methods of antifungal susceptibility testing of yeasts. J Clin Microbiol 1997; 35:2878-82. [PMID: 9350751 PMCID: PMC230079 DOI: 10.1128/jcm.35.11.2878-2882.1997] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We determined the fluconazole MICs for 101 clinical isolates of Candida and Cryptococcus neoformans using the macro- and microdilution methods recommended by the National Committee for Clinical Laboratory Standards. We compared the MICs obtained by these methods with those obtained by a photometric assay that quantified the reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) by viable fungi. The MIC determined by this method was defined as the highest fluconazole concentration associated with the first precipitous drop in optical density. For Candida, both the MTT and the microdilution methods demonstrated excellent agreement with the standard macrodilution method. The MTT method, however, generated MICs at 24 h that were comparable to those generated by the standard macrodilution method, whereas the microdilution method required 48 h. For C. neoformans, the levels of agreement between the MICs determined by the MTT and microdilution methods after 48 h and those determined by the standard 72-h macrodilution method were 94% (29 of 31) and 94% (29 of 31), respectively. The MTT method therefore provided results comparable to those of currently recommended methods and had the advantages of a more rapid turnaround time and potential adaptability to use as an automated system. Furthermore, the MICs determined by the MTT method were determined photometrically, thereby eliminating reader bias.
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Affiliation(s)
- C J Clancy
- Department of Medicine, College of Medicine, University of Florida, and the Veterans Affairs Medical Center, Gainesville 32610, USA
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99
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Abstract
A rapid flow cytometric assay for in vitro antifungal drug susceptibility testing was developed by adapting the proposed reference method for broth macrodilution testing of yeasts. Membrane permeability changes caused by the antifungal agent were measured by flow cytometry using propidium iodide, a nucleic acid-binding fluorochrome largely excluded by the intact cell membrane. We determined the in vitro susceptibility of 31 Candida albicans isolates and two quality control strains (Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258) to amphotericin B and fluconazole. Amphotericin B MICs ranged from 0.03 to 2.0 microg/ml, while fluconazole MICs ranged from 0.125 to 128 microg/ml. This method results in clear-cut endpoints that were reproducible. Four-hour incubation was required for fluconazole, whereas a 2-h incubation was sufficient for amphotericin B to provide MICs comparable to the reference macrodilution method developed by the National Committee for Clinical Laboratory Standards Subcommittee on Antifungal Susceptibility Tests. Results of these studies show that flow cytometry provides a rapid and sensitive in vitro method for antifungal susceptibility testing of C. albicans.
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Affiliation(s)
- R Ramani
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, Albany 12201-2002, USA.
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100
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Wilson RB, Roof DM. Respiratory deficiency due to loss of mitochondrial DNA in yeast lacking the frataxin homologue. Nat Genet 1997; 16:352-7. [PMID: 9241271 DOI: 10.1038/ng0897-352] [Citation(s) in RCA: 223] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive degenerative disorder that primarily affects the nervous system and heart. Patients with FRDA have point mutations or trinucleotide repeat expansions in both alleles of FRDA, which encodes a protein termed frataxin. We show that the yeast frataxin homologue, which we have named YFH1, localizes to mitochondria and is required to maintain mitochondrial DNA. The YFH1-homologous domain of frataxin functions in yeast and a disease-associated missense mutation of this domain, or the corresponding domain in YFH1, reduces function. Our data suggest that mitochondrial dysfunction contributes to FRDA pathophysiology.
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Affiliation(s)
- R B Wilson
- Department of Pathology, University of Pennsylvania, Philadelphia 19104, USA.
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