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David M Geiser - One of the best experts on this subject based on the ideXlab platform.
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Sexual structures in Aspergillus: morphology, importance and genomics
Medical Mycology, 2009Co-Authors: David M GeiserAbstract:The genus Aspergillus comprises a few hundred species sharing a common asexual spore forming structure, the aspergillum. Approximately one-third of these species also produce a sexual stage, all but five of which are known to be homothallic. Sexual stages associated with Aspergillus fall into approximately ten different genera, reflecting a tremendous degree of phylogenetic and biological diversity. Sexual stages in Aspergillus are plectomycetous, typical for the order in which it resides, the Eurotiales. Theoretically, a homothallic Aspergillus species can produce both asexual conidia and sexual ascospores in both clonal and recombinant fashion, although the actual significance of these potential modes of reproduction is unclear. Aspergillus species with known sexual stages tend to be minor players in infections of humans, perhaps because of their tendency to produce fewer asexual spores compared to their non-teleomorphic congeners. The discovery of population genetic and genomic evidence for sex in spec...
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Sexual structures in Aspergillus: morphology, importance and genomics.
Medical mycology, 2008Co-Authors: David M GeiserAbstract:The genus Aspergillus comprises a few hundred species sharing a common asexual spore forming structure, the aspergillum. Approximately one-third of these species also produce a sexual stage, all but five of which are known to be homothallic. Sexual stages associated with Aspergillus fall into approximately ten different genera, reflecting a tremendous degree of phylogenetic and biological diversity. Sexual stages in Aspergillus are plectomycetous, typical for the order in which it resides, the Eurotiales. Theoretically, a homothallic Aspergillus species can produce both asexual conidia and sexual ascospores in both clonal and recombinant fashion, although the actual significance of these potential modes of reproduction is unclear. Aspergillus species with known sexual stages tend to be minor players in infections of humans, perhaps because of their tendency to produce fewer asexual spores compared to their non-teleomorphic congeners. The discovery of population genetic and genomic evidence for sex in species with no known sexual stage indicates that no assumptions can be made about the clonal versus recombinant life histories of a species based on its known mitotic and/or meiotic reproductive modes.
Jens Christian Frisvad - One of the best experts on this subject based on the ideXlab platform.
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Aspergillus saccharolyticus sp. nov., a black Aspergillus species isolated in Denmark.
International Journal of Systematic and Evolutionary Microbiology, 2011Co-Authors: Annette Sørensen, Peter Stephensen Lübeck, Mette Lübeck, Kristian Fog Nielsen, Birgitte Kiær Ahring, Philip Teller, Jens Christian FrisvadAbstract:A novel species, Aspergillus saccharolyticus sp. nov., belonging to the Aspergillus section Nigri group is described. This species was isolated in Denmark from treated hardwood. Its taxonomic status was determined using a polyphasic taxonomic approach including phenotypic (morphology and extrolite profiles) and molecular (β-tubulin, internal transcribed spacer and calmodulin gene sequences, and universally primed PCR fingerprinting) analysis. Phenotypic and molecular data enabled this novel species to be clearly distinguished from other black aspergilli. A. saccharolyticus is a uniseriate Aspergillus species that is morphologically similar to Aspergillus japonicus and Aspergillus aculeatus, but has a totally different extrolite profile compared to any known Aspergillus species. The type strain of A. saccharolyticus sp. nov. is CBS 127449T ( = IBT 28509T).
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Aspergillus niger contains the cryptic phylogenetic species a awamori
Fungal Biology, 2011Co-Authors: Giancarlo Perrone, Gaetano Stea, Filomena Epifani, Janos Varga, Jens Christian Frisvad, Robert A. SamsonAbstract:Aspergillus section Nigri is an important group of species for food and medical mycology, and biotechnology. The Aspergillus niger 'aggregate' represents its most complicated taxonomic subgroup containing eight morphologically indistinguishable taxa: A. niger, Aspergillus tubingensis, Aspergillus acidus, Aspergillus brasiliensis, Aspergillus costaricaensis, Aspergillus lacticoffeatus, Aspergillus piperis, and Aspergillus vadensis. Aspergillus awamori, first described by Nakazawa, has been compared taxonomically with other black aspergilli and recently it has been treated as a synonym of A. niger. Phylogenetic analyses of sequences generated from portions of three genes coding for the proteins β-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species within this population, A. awamori. Morphological, physiological, ecological and chemical data overlap occurred between A. niger and the cryptic A. awamori, however the splitting of these two species was also supported by AFLP analysis of the full genome. Isolates in both phylospecies can produce the mycotoxins ochratoxin A and fumonisin B₂, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-γ-pyrones. In addition, sequence analysis of four putative A. awamori strains from Japan, used in the koji industrial fermentation, revealed that none of these strains belong to the A. awamori phylospecies.
Brian P. H. Tse - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity of Aspergillus species isolated from onychomycosis and Aspergillus hongkongensis sp. nov., with implications to antifungal susceptibility testing
Diagnostic microbiology and infectious disease, 2015Co-Authors: Chi-ching Tsang, Teresa W. S. Hui, Kim-chung Lee, Jonathan H. K. Chen, Antonio H. Y. Ngan, Emily W. T. Tam, Jasper F. W. Chan, Mei Cheung, Brian P. H. TseAbstract:Thirteen Aspergillus isolates recovered from nails of 13 patients (fingernails, n=2; toenails, n=11) with onychomycosis were characterized. Twelve strains were identified by multilocus sequencing as Aspergillus spp. (Aspergillus sydowii [n=4], Aspergillus welwitschiae [n=3], Aspergillus terreus [n=2], Aspergillus flavus [n=1], Aspergillus tubingensis [n=1], and Aspergillus unguis [n=1]). Isolates of A. terreus, A. flavus, and A. unguis were also identifiable by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The 13th isolate (HKU49(T)) possessed unique morphological characteristics different from other Aspergillus spp. Molecular characterization also unambiguously showed that HKU49(T) was distinct from other Aspergillus spp. We propose the novel species Aspergillus hongkongensis to describe this previously unknown fungus. Antifungal susceptibility testing showed most Aspergillus isolates had low MICs against itraconazole and voriconazole, but all Aspergillus isolates had high MICs against fluconazole. A diverse spectrum of Aspergillus species is associated with onychomycosis. Itraconazole and voriconazole are probably better drug options for Aspergillus onychomycosis.
Nuri Kiraz - One of the best experts on this subject based on the ideXlab platform.
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in vitro susceptibilities of Aspergillus spp causing otomycosis to amphotericin b voriconazole and itraconazole
Mycoses, 2007Co-Authors: Ayse Demet Kaya, Nuri KirazAbstract:Summary Otomycosis is worldwide in distribution and most commonly caused by Aspergillus species. Amphotericin B, itraconazole and voriconazole are used for the treatment of aspergillosis, but recently an increase in resistance to these agents has been reported. We aimed at investigating the in vitro activities of amphotericin B, voriconazole and itraconazole against Aspergillus isolates causing otomycosis. Mycological analysis of samples from the ear canals of patients was performed by culturing onto Sabouraud Dextrose Agar and by evaluating microscopically. Aspergillus species were identified with colony morphology and microscopic appearance, and tested for susceptibilities to amphotericin B, itraconazole and voriconazole by the CLSI reference broth microdilution method (M38-A document). A total of 120 isolates from 120 patients, comprising 57 Aspergillus niger, 42 Aspergillus fumigatus, nine Aspergillus flavus, six Aspergillus nidulans and six Aspergillus terreus strains were tested. No resistance was determined against amphotericin B and voriconazole, while six A. fumigatus and three A. niger isolates were resistant to itraconazole. In vitro data obtained in this study showed the resistance to itraconazole, while all of the isolates were susceptible to voriconazole and amphotericin B. Voriconazole seemed to be an alternative in the treatment of infections related to Aspergillus spp. but further studies are needed to learn more about the antifungal resistance of different species of Aspergillus to different agents.
Claudio L Donnici - One of the best experts on this subject based on the ideXlab platform.
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In vitro susceptibility of Aspergillus spp. to dithiocarbamate organoruthenium compounds.
Mycoses, 2010Co-Authors: Luciano José Nogueira, Sheila Rodrigues Oliveira, Thais Furtado Ferreira Magalhães, Milena Batista Oliveira, Cleide V. B. Martins, Ana Cândida Araújo E Silva, Miriam T P Lopes, Maria Helena Araujo, Maria Aparecida De Resende, Claudio L DonniciAbstract:: The in vitro antifungal activity of ruthenium dithiocarbamate compounds (1-5) was investigated and assessed for its activity against seven different species of Aspergillus (Aspergillus clavatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus nomius, Aspergillus tamarii and Aspergillus terreus). Analysis of in vitro susceptibility was performed using broth microdilution assay following the Clinical and Laboratory Standards Institute guidelines for filamentous fungi. The cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Aspergillus clavatus and A. fumigatus were more susceptible species for complexes 1 and 2. Other complexes showed excellent minimum inhibitory concentration (4-64 μg ml(-1)) against most microorganisms. Complexes 1 and 2 are respectively 180- and 95-fold more active than the corresponding free ligands against A. clavatus and the complex 5 is 46-fold more active than free ligand against A. niger. Aspergillus niger was more susceptible to the action of the complexes 1 and 5 (16 μg ml(-1)). A low cytotoxic activity (IC(50) > 10(-6) mol l(-1) ) on normal mammalian cells (BHK-21) to the evaluated complexes was measured. Ruthenium complexes are promising antifungal agents against the development of novel effective drug against different species of Aspergillus; however, for A. nomius and A. terreus, they were not active in the highest concentration tested.
