{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T04:33:18Z","timestamp":1790742798553,"version":"4.1.0"},"reference-count":57,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2016,3,24]],"date-time":"2016-03-24T00:00:00Z","timestamp":1458777600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Higher Education and Scientific Research","award":["S923"],"award-info":[{"award-number":["S923"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The dematiaceous (melanised) fungus Lomentospora (Scedosporium) prolificans is a life-threatening opportunistic pathogen of immunocompromised humans, resistant to anti-fungal drugs. Melanin has been shown to protect human pathogenic fungi against antifungal drugs, oxidative killing and environmental stresses. To determine the protective role of melanin in L. prolificans to oxidative killing (H2O2), UV radiation and the polyene anti-fungal drug amphotericin B, targeted gene disruption was used to generate mutants of the pathogen lacking the dihydroxynaphthalene (DHN)-melanin biosynthetic enzymes polyketide synthase (PKS1), tetrahydroxynapthalene reductase (4HNR) and scytalone dehydratase (SCD1). Infectious propagules (spores) of the wild-type strain 3.1 were black\/brown, whereas spores of the PKS-deficient mutant \u0394Lppks1::hph were white. Complementation of the albino mutant \u0394Lppks1::hph restored the black-brown spore pigmentation, while the 4HNR-deficient mutant \u0394Lp4hnr::hph and SCD-deficient mutant \u0394Lpscd1::hph both produced orange-yellow spores. The mutants \u0394Lppks1::hph and \u0394Lp4hnr::hph showed significant reductions in spore survival following H2O2 treatment, while spores of \u0394Lpscd1::hph and the \u0394Lppks1::hph complemented strain \u0394Lppks1::hph:PKS showed spore survivals similar to strain 3.1. Spores of the mutants \u0394Lp4hnr::hph and \u0394Lpscd1::hph and complemented strain \u0394Lppks1::hph:PKS showed spore survivals similar to 3.1 following exposure to UV radiation, but survival of \u0394Lppks1::hph spores was significantly reduced compared to the wild-type strain. Strain 3.1 and mutants \u0394Lp4hnr::hph and \u0394Lppks1::hph:PKS were resistant to amphotericin B while, paradoxically, the PKS1- and SCD1-deficient mutants showed significant increases in growth in the presence of the antifungal drug. Taken together, these results show that while melanin plays a protective role in the survival of the pathogen to oxidative killing and UV radiation, melanin does not contribute to its resistance to amphotericin B.<\/jats:p>","DOI":"10.3390\/ijms17040444","type":"journal-article","created":{"date-parts":[[2016,3,24]],"date-time":"2016-03-24T11:55:16Z","timestamp":1458820516000},"page":"444","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":30,"title":["Targeted Disruption of Melanin Biosynthesis Genes in the Human Pathogenic Fungus Lomentospora prolificans and Its Consequences for Pathogen Survival"],"prefix":"10.3390","volume":"17","author":[{"given":"Ayat","family":"Al-Laaeiby","sequence":"first","affiliation":[{"name":"Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK"},{"name":"Cell and Biotechnology Research Unit, College of Science, University of Basrah, Basrah 61004, Iraq"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Kershaw","sequence":"additional","affiliation":[{"name":"Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tina","family":"Penn","sequence":"additional","affiliation":[{"name":"Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher","family":"Thornton","sequence":"additional","affiliation":[{"name":"Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,3,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3290","DOI":"10.1128\/jcm.33.12.3290-3295.1995","article-title":"Nosocomial outbreak caused by Scedosporium prolificans (inflatum): Four fatal cases in leukemic patients","volume":"33","author":"Alvarez","year":"1995","journal-title":"J. Clin. Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1097\/00005792-199707000-00004","article-title":"Deep infections caused by Scedosporium prolificans: A report on 16 cases in Spain and a review of the literature","volume":"76","author":"Berenguer","year":"1997","journal-title":"Medicine"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1080\/00365540600786564","article-title":"Scedosporium prolificans brain abscess in a patient with chronic granulomatous disease: Successful combination therapy with voriconazole and terbinafine","volume":"39","author":"Bhat","year":"2007","journal-title":"Scand. J. Infect. Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1170","DOI":"10.3201\/eid1308.060576","article-title":"Infection with Scedosporium apiospermum and S. prolificans, Australia","volume":"13","author":"Cooley","year":"2007","journal-title":"Emerg. Infect. Dis."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1128\/CMR.00039-07","article-title":"Infections caused by Scedosporium spp.","volume":"2","author":"Cortez","year":"2008","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"672","DOI":"10.1111\/j.1469-0691.1999.tb00513.x","article-title":"Clinical, pathologic and epidemiologic features of infection with Scedosporium prolificans: Four cases and review","volume":"5","author":"Gosbell","year":"1999","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1093\/jac\/dki218","article-title":"Changing patterns and trends in systemic fungal infections","volume":"56","author":"Richardson","year":"2005","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1692","DOI":"10.1086\/323895","article-title":"Trends in the epidemiology of opportunistic fungal infections: Predisposing factors and the impact of antimicrobial use practices","volume":"33","author":"Singh","year":"2001","journal-title":"Clin. Infect. Dis."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1080\/13693780802524506","article-title":"Epidemiology and outcome of Scedosporium prolificans infections, a review of 162 cases","volume":"47","author":"Berenguer","year":"2009","journal-title":"Med. Mycol."},{"key":"ref_10","first-page":"289","article-title":"Three cases of Tsunami lung in which genus Scedosporium was isolated","volume":"22","author":"Hatakeyama","year":"2012","journal-title":"J. Jpn. Soc. Clin. Microbiol."},{"key":"ref_11","first-page":"74","article-title":"Two cases of severe pneumonia after the 2011 Great East Japan earthquake","volume":"3","author":"Nakadate","year":"2012","journal-title":"West. Pac. Surveill. Response J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/j.jcf.2014.12.014","article-title":"Prevalence of Scedosporium species and Lomentospora prolificans in patients with cystic fibrosis in a multicenter trial by use of a selective medium","volume":"14","author":"Sedlacek","year":"2015","journal-title":"J. Cyst. Fibros."},{"key":"ref_13","first-page":"97","article-title":"Drug resistance in fungi\u2014An emerging problem","volume":"15","author":"Chakrabarti","year":"2011","journal-title":"Reg. Health Forum"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/j.tim.2010.02.004","article-title":"Therapy for fungal diseases: Opportunities and priorities","volume":"18","author":"Denning","year":"2010","journal-title":"Trends Microbiol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1093\/jac\/49.suppl_1.7","article-title":"Amphotericin B: Spectrum and resistance","volume":"1","author":"Ellis","year":"2002","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1086\/524071","article-title":"Resistance to antifungal agents: Mechanisms and clinical impact","volume":"46","author":"Kanafani","year":"2008","journal-title":"Clin. Infect. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2009","DOI":"10.1128\/AAC.00163-06","article-title":"In vitro activities of posaconazole, fluconazole, itraconazole, voriconazole, and amphotericin B against a large collection of clinically important molds and yeasts","volume":"50","author":"Sabatelli","year":"2006","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1155\/2012\/713687","article-title":"Antifungal resistance and new strategies to control fungal infections","volume":"2012","author":"Vandeputte","year":"2012","journal-title":"Int. J. Microbiol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1128\/CMR.13.4.708","article-title":"Pathogenic roles for fungal melanins","volume":"13","author":"Jacobson","year":"2000","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/S0378-1097(97)00239-5","article-title":"Melanization affects susceptibility of Cryptococcus neoformans to heat and cold","volume":"153","author":"Rosas","year":"1997","journal-title":"FEMS Microbiol. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1023\/A:1010977107089","article-title":"Melanization decreases the susceptibility of Cryptococcus neoformans to enzymatic degradation","volume":"151","author":"Rosas","year":"2000","journal-title":"Mycopathologia"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/S1087-1845(02)00526-1","article-title":"Biosynthesis of fungal melanins and their importance for human pathogenic fungi","volume":"38","author":"Langfelder","year":"2003","journal-title":"Fungal Genet. Biol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"S3","DOI":"10.1016\/j.amjmed.2011.11.001","article-title":"Antifungal drug resistance: Mechanisms, epidemiology, and consequences for treatment","volume":"125","author":"Pfaller","year":"2012","journal-title":"Am. J. Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1111\/j.1348-0421.2003.tb03395.x","article-title":"Effects of melanin upon susceptibility of Cryptococcus to antifungals","volume":"47","author":"Ikeda","year":"2003","journal-title":"Microbiol. Immunol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3519","DOI":"10.1128\/AAC.00545-06","article-title":"Impact of melanin on microbial virulence and clinical resistance to antimicrobial compounds","volume":"50","author":"Nosanchuk","year":"2006","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1186\/1471-2180-10-80","article-title":"Melanin in Fonsecaea pedrosoi: A trap for oxidative radicals","volume":"10","author":"Cunha","year":"2010","journal-title":"BMC Microbiol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1080\/13693780412331271081","article-title":"Effect of melanisation upon porosity of the Cryptococcal cell wall","volume":"43","author":"Jacobson","year":"2005","journal-title":"Med. Mycol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1046\/j.1462-5814.2003.00268.x","article-title":"The contribution of melanin to microbial pathogenesis","volume":"5","author":"Nonsanchuk","year":"2003","journal-title":"Cell. Microbiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3004","DOI":"10.1128\/iai.62.7.3004-3007.1994","article-title":"Susceptibility of melanized and non-melanized Cryptococcus neoformans to nitrogen- and oxygen-derived oxidants","volume":"62","author":"Wang","year":"1994","journal-title":"Infect. Immun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1128\/IAI.67.1.94-101.1999","article-title":"Effect of melanin and carotenoids of Exophiala (Wangiella) dermatitidis on phagocytosis, oxidative burst, and killing by human neutrophils","volume":"67","author":"Schnitzler","year":"1999","journal-title":"Infect. Immun."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1046\/j.1365-280X.1999.00218.x","article-title":"Melanin as a potential cryptococcal defence against microbicidal proteins","volume":"37","author":"Doering","year":"1999","journal-title":"Med. Mycol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1111\/j.1755-148X.2007.00430.x","article-title":"The radioprotective properties of fungal melanin are a function of its chemical composition, stable radical presence and spatial arrangement","volume":"21","author":"Dadachova","year":"2008","journal-title":"Pigment Cell Melanoma Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3864","DOI":"10.1128\/aem.60.10.3864-3866.1994","article-title":"Decreased susceptibility of melanised Cryptococcus neoformans to the fungicidal effects of ultraviolet light","volume":"60","author":"Wang","year":"1994","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"S75","DOI":"10.1080\/13693780400028967","article-title":"Aspergillus fumigatus conidial pigment and cAMP signal transduction: Significance for virulence","volume":"43","author":"Brakhage","year":"2005","journal-title":"Med. Mycol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1007\/s11046-007-9061-4","article-title":"Melanin as a virulence factor of Paracoccidioides brasiliensis and other dimorphic pathogenic fungi: Minireview","volume":"165","author":"Taborda","year":"2008","journal-title":"Mycopathologia"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"931","DOI":"10.1007\/s00253-011-3777-2","article-title":"Synthesis and assembly of fungal melanin","volume":"93","author":"Eisenman","year":"2012","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Anke, T., and Weber, D. (2009). The Mycota Physiology and Genetics XV, Springer-Verlag.","DOI":"10.1007\/978-3-642-00286-1"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1023","DOI":"10.1111\/1462-2920.12470","article-title":"Identifying the emerging human pathogen Scedosporium prolificans by using a species-specific monoclonal antibody that binds to the melanin biosynthetic enzyme tetrahydroxynaphthalene reductase","volume":"17","author":"Thornton","year":"2015","journal-title":"Environ. Microbiol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"973","DOI":"10.1016\/j.fgb.2004.08.001","article-title":"Double-joint PCR: A PCR-based molecular tool for gene manipulations in filamentous fungi","volume":"41","author":"Yu","year":"2004","journal-title":"Fungal Genet. Biol."},{"key":"ref_40","first-page":"52","article-title":"A series of vectors for fungal transformation","volume":"44","author":"Sweigard","year":"1997","journal-title":"Fungal Genet. Newsl."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3394","DOI":"10.1128\/AAC.46.11.3394-3400.2002","article-title":"Melanization of Cryptococcus neoformans and Histoplasma capsulatum reduces their susceptibilities to amphotericin B and caspofungin","volume":"46","author":"Casadevall","year":"2002","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1007\/s00203-009-0489-4","article-title":"Gene-specific disruption in the filamentous fungus Cercospora nicotianae using a split-marker approach","volume":"191","author":"You","year":"2009","journal-title":"Arch. Microbiol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1007\/s00284-002-3858-7","article-title":"Isolation, characterization, and antifungal susceptibility of melanin-deficient mutants of Scedosporium prolificans","volume":"46","year":"2003","journal-title":"Curr. Microbiol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1007\/s00294-010-0294-2","article-title":"Agrobacterium-meditated gene disruption using split-marker in Grosmannia clavigera, a mountain pine beetle associated pathogen","volume":"56","author":"Wang","year":"2010","journal-title":"Curr. Genet."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"3031","DOI":"10.1128\/JB.180.12.3031-3038.1998","article-title":"The developmentally regulated alb1 gene of Aspergillus fumigatus: Its role in modulation of conidial morphology and virulence","volume":"180","author":"Tsai","year":"1998","journal-title":"J. Bacteriol."},{"key":"ref_46","first-page":"1","article-title":"Insertional mutagenesis and characterization of a polyketide synthase gene (PKS1) required for melanin biosynthesis in Bipolaris oryzae","volume":"238","author":"Moriwaki","year":"2004","journal-title":"FEMS Microbiol. Lett."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Tseng, M., Chung, C-L, and Tzean, S-S. (2014). Mechanisms relevant to the enhanced virulence of a dihydroxynaphthalene-melanin metabolically engineered entomopathogen. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0090473"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1007\/s10327-011-0356-4","article-title":"Functional analysis of the melanin biosynthesis genes ALM1 and BRM2\u20131 in the tomato pathotype of Alternaria alternata","volume":"78","author":"Kheder","year":"2012","journal-title":"J. Gen. Plant Pathol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"3696","DOI":"10.1128\/IAI.68.6.3696-3703.2000","article-title":"Biosynthesis and function of melanin in Sporothrix schenckii","volume":"68","author":"Wheeler","year":"2000","journal-title":"Infect. Immun."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1016\/S0891-5849(98)00234-2","article-title":"Free radical scavenging properties of melanin: Interaction of eu- and pheo-melanin models with reducing and oxidizing radicals","volume":"26","author":"Sarna","year":"1999","journal-title":"Free Radic. Biol. Med."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"3750","DOI":"10.1111\/j.1742-4658.2010.07776.x","article-title":"High diversity of polyketide synthase genes and the melanin biosynthesis gene cluster in Penicillium marneffei","volume":"277","author":"Woo","year":"2010","journal-title":"FEBS J."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1555","DOI":"10.1128\/AAC.00854-09","article-title":"Transcriptional regulation of chitin synthases by calcineurin controls paradoxical growth of Aspergillus fumigatus in response to caspofungin","volume":"54","author":"Fortwendel","year":"2010","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1071","DOI":"10.1128\/AAC.00946-13","article-title":"Paradoxical growth of Candida albicans in the presence of caspofungin is associated with multiple cell wall rearrangements and decreased virulence","volume":"58","author":"Rueda","year":"2014","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1111\/j.1600-0749.1992.tb00570.x","article-title":"Effect of amphotericin B on dopachrome tautomerase activity and other melanogenic parameters in cultured B16\/F10 melanoma cells","volume":"5","author":"Peinado","year":"2006","journal-title":"Pigment Cell Res."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1155\/2014\/498276","article-title":"Melanins: Skin pigments and much more\u2014Types, structural models, biological functions, and formation routes","volume":"2014","author":"Solano","year":"2014","journal-title":"New J. Sci."},{"key":"ref_56","unstructured":"Alastruey-Izquierdo, A., Castelli, M., Bernal-Martinez, L., and Tudela, J. (2011). Pseudallescheria and Scedosporium Molecular Detection of Human Fungal Pathogens, Taylor & Francis Group."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/S0022-2836(75)80083-0","article-title":"Detection of specific sequences among DNA fragments separated by gel electrophoresis","volume":"98","author":"Southern","year":"1975","journal-title":"J. Mol. Biol."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/17\/4\/444\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:21:14Z","timestamp":1760210474000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/17\/4\/444"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,3,24]]},"references-count":57,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2016,4]]}},"alternative-id":["ijms17040444"],"URL":"https:\/\/doi.org\/10.3390\/ijms17040444","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,3,24]]}}}