Agents of human chromoblastomycosis,a skin disease almost exclusively caused by members of the order Chaetothyriales,are assumed to be traumatically inoculated into the skin with sharp environmental materials such as ...Agents of human chromoblastomycosis,a skin disease almost exclusively caused by members of the order Chaetothyriales,are assumed to be traumatically inoculated into the skin with sharp environmental materials such as plant thorns or wooden splinters carrying the respective opportunist.In the supposition that such fungi should have their main habitat in the environment,we investigated the occurrence of black fungi in living areas of patients with chromoblastomycosis.In South America Fonsecaea agents are prevalent as agents of the disease,while also related Cladophialophora species,known from other types of skin infections,are known from the continent.Ninety environmental isolates were preliminarily selected as possible agents of chromoblastomycosis,based on morphology.Judging from ITS sequence data isolates were attributed to the genera Cladophialophora,Cyphellophora,Exophiala,Fonsecaea,Phialophora,and Veronaea.A total of 45 fungi morphologically identified as Fonsecaea or Cladophialophora isolated from debris and thorns of living prickly plants in Brazil were processed for taxonomic studies.Phylogenetic analysis revealed that the isolates indeed belonged to the Chaetothyriales,but only rarely an agent of chromoblastomycosis was concerned;only two strains of F.pedrosoi and one F.monophora were isolated from debris plants.The remaining isolates belonged to hitherto unknown molecular siblings of Fonsecaea.Two novel taxa are introduced.展开更多
Cyphellophora is a genus of black yeast-like fungi characterised by having simple phialides with multiseptate,curved conidia.Judging from SSU and LSU data,Cyphellophora was found to be located in a well-supported clad...Cyphellophora is a genus of black yeast-like fungi characterised by having simple phialides with multiseptate,curved conidia.Judging from SSU and LSU data,Cyphellophora was found to be located in a well-supported clade within the Chaetothyriales comprising a number of species occurring on human skin and nail.Cyphellophora is phylogenetically close to Phialophora europaea,P.reptans and P.oxyspora,though morphologically these species produce singlecelled phialoconidia rather than multiseptate ones.Pseudomicrodochium suttonii and P.fusarioides have dark colonies and phylogenetically fit in with Cyphellophora;the type species of Pseudomicrodochium,P.aciculare,has similar,septate conidia but has a hyaline thallus.In the present study,multilocus phylogenetic analyses were combined with morphology and physiology.Sequences of the internal transcribed spacer region,the DNA dependent RNA polymerase II largest subunit and the partial beta tubulin gene were analysed for a set of 30 strains.Two novel species,Cyphellophora pauciseptata and Phialophora ambigua were discovered.Cyphellophora eucalypti was reduced to synonymy of C.guyanensis.The role of the studied fungi between colonization and infection of human skin was discussed.Putative virulence factors for these black yeast-like fungi were hypothesized to be the ability to assimilate monoaromatic hydrocarbons,to produce melanin pigments,and to tolerate the temperature of epidermal human skin.展开更多
基金The work of Vania A.Vicente was supported by a Brazilian Government fellowshipby financial support from the Brazilian Federal Agency for Support and Evaluation of Graduate Education-CAPES and Conselho Nacional de Pesquisa(CNPq).The work of Mohammad Javad Najafzadeh was supported by the Faculty of Medicine,Mashhad University of Medical Sciences,Mashhad,Iran.
文摘Agents of human chromoblastomycosis,a skin disease almost exclusively caused by members of the order Chaetothyriales,are assumed to be traumatically inoculated into the skin with sharp environmental materials such as plant thorns or wooden splinters carrying the respective opportunist.In the supposition that such fungi should have their main habitat in the environment,we investigated the occurrence of black fungi in living areas of patients with chromoblastomycosis.In South America Fonsecaea agents are prevalent as agents of the disease,while also related Cladophialophora species,known from other types of skin infections,are known from the continent.Ninety environmental isolates were preliminarily selected as possible agents of chromoblastomycosis,based on morphology.Judging from ITS sequence data isolates were attributed to the genera Cladophialophora,Cyphellophora,Exophiala,Fonsecaea,Phialophora,and Veronaea.A total of 45 fungi morphologically identified as Fonsecaea or Cladophialophora isolated from debris and thorns of living prickly plants in Brazil were processed for taxonomic studies.Phylogenetic analysis revealed that the isolates indeed belonged to the Chaetothyriales,but only rarely an agent of chromoblastomycosis was concerned;only two strains of F.pedrosoi and one F.monophora were isolated from debris plants.The remaining isolates belonged to hitherto unknown molecular siblings of Fonsecaea.Two novel taxa are introduced.
基金This work was supported by the project 11CPD009 of the china desk of the Netherlands Academy of Sciences.
文摘Cyphellophora is a genus of black yeast-like fungi characterised by having simple phialides with multiseptate,curved conidia.Judging from SSU and LSU data,Cyphellophora was found to be located in a well-supported clade within the Chaetothyriales comprising a number of species occurring on human skin and nail.Cyphellophora is phylogenetically close to Phialophora europaea,P.reptans and P.oxyspora,though morphologically these species produce singlecelled phialoconidia rather than multiseptate ones.Pseudomicrodochium suttonii and P.fusarioides have dark colonies and phylogenetically fit in with Cyphellophora;the type species of Pseudomicrodochium,P.aciculare,has similar,septate conidia but has a hyaline thallus.In the present study,multilocus phylogenetic analyses were combined with morphology and physiology.Sequences of the internal transcribed spacer region,the DNA dependent RNA polymerase II largest subunit and the partial beta tubulin gene were analysed for a set of 30 strains.Two novel species,Cyphellophora pauciseptata and Phialophora ambigua were discovered.Cyphellophora eucalypti was reduced to synonymy of C.guyanensis.The role of the studied fungi between colonization and infection of human skin was discussed.Putative virulence factors for these black yeast-like fungi were hypothesized to be the ability to assimilate monoaromatic hydrocarbons,to produce melanin pigments,and to tolerate the temperature of epidermal human skin.
