154 research outputs found

    Physically Triggered Morphology Changes in a Novel Acremonium Isolate Cultivated in Precisely Engineered Microfabricated Environments.

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    Fungi are strongly affected by their physical environment. Microfabrication offers the possibility of creating new culture environments and ecosystems with defined characteristics. Here, we report the isolation of a novel member of the fungal genus Acremonium using a microengineered cultivation chip. This isolate was unusual in that it organizes into macroscopic structures when initially cultivated within microwells with a porous aluminum oxide (PAO) base. These "templated mycelial bundles" (TMB) were formed from masses of parallel hyphae with side branching suppressed. TMB were highly hydrated, facilitating the passive movement of solutes along the bundle. By using a range of culture chips, it was deduced that the critical factors in triggering the TMB were growth in microwells from 50 to 300 渭m in diameter with a PAO base. Cultivation experiments, using spores and pigments as tracking agents, indicate that bulk growth of the TMB occurs at the base. TMB morphology is highly coherent and is maintained after growing out of the microwells. TMB can explore their environment by developing unbundled lateral hyphae; TMB only followed if nutrients were available. Because of the ease of fabricating numerous microstructures, we suggest this is a productive approach for exploring morphology and growth in multicellular microorganisms and microbial communities

    Multiple hybridization events punctuate the evolutionary trajectory of malassezia furfur

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    Malassezia species are important fungal skin commensals and are part of the normal microbiota of humans and other animals. However, under certain circumstances these fungi can also display a pathogenic behavior. For example, Malassezia furfur is a common commensal of human skin and yet is often responsible for skin disorders but also systemic infections. Comparative genomics analysis of M. furfur revealed that some isolates have a hybrid origin, similar to several other recently described hybrid fungal pathogens. Because hybrid species exhibit genomic plasticity that can impact phenotypes, we sought to elucidate the genomic evolution and phenotypic characteristics of M. furfur hybrids in comparison to their parental lineages. To this end, we performed a comparative genomics analysis between hybrid strains and their presumptive parental lineages and assessed phenotypic characteristics. Our results provide evidence that at least two distinct hybridization events occurred between the same parental lineages and that the parental strains may have originally been hybrids themselves. Analysis of the mating-type locus reveals that M. furfur has a pseudobipolar mating system and provides evidence that after sexual liaisons of mating compatible cells, hybridization involved cell-cell fusion leading to a diploid/aneuploid state. This study provides new insights into the evolutionary trajectory of M. furfur and contributes with valuable genomic resources for future pathogenicity studies. IMPORTANCE Malassezia furfur is a common commensal member of human/animal microbiota that is also associated with several pathogenic states. Recent studies report involvement of Malassezia species in Crohn鈥檚 disease, a type of inflammatory bowel disease, pancreatic cancer progression, and exacerbation of cystic fibrosis. A recent genomics analysis of M. furfur revealed the existence of hybrid isolates and identified their putative parental lineages. In this study, we explored the genomic and phenotypic features of these hybrids in comparison to their putative parental lineages. Our results revealed the existence of a pseudobipolar mating system in this species and showed evidence for the occurrence of multiple hybridization events in the evolutionary trajectory of M. furfur. These findings significantly advance our understanding of the evolution of this commensal microbe and are relevant for future studies exploring the role of hybridization in the adaptation to new niches or environments, including the emergence of pathogenicity.We thank Timothy James for reviewing our manuscript, Bart Kraak for some exploratory PCR and microscopy work, Simon Denil for assistance with the initial bioinformatics assessment of strain CBS1878, Claudia Cafarchia for providing strain CD866, and Marina Marcet-Houben for helpful discussions on the bioinformatics analyses. This study was supported by the European Union鈥檚 Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement H2020-MSCA-ITN-2014-642095. The T.G. group also acknowledges support from the Spanish Ministry of Economy, Industry, and Competitiveness (MEIC) for the EMBL partnership, and grants Centro de Excelencia Severo Ochoa 2013-2017 SEV-2012-0208 and BFU2015-67107 cofounded by European Regional Development Fund (ERDF); from the CERCA Program/Generalitat de Catalunya; from the Catalan Research Agency (AGAUR) SGR857; and from grants from the European Union鈥檚 Horizon 2020 research and innovation program under the grant agreement ERC-2016-724173. T.G. also receives support from an INB grant (PT17/0009/0023鈥擨SCIII-SGEFI/ERDF). G.I. and J.H. were supported by NIH/NIAID R37 award AI39115-24 and R01 award AI50113-16A1. J.H. is fellow and codirector of the CIFAR program Fungal Kingdom: Threats and Opportunities. T.L.D. was supported by the Skin Research Institute of Singapore Fund (IAF-PP H17/01/a0/004).Peer ReviewedPostprint (published version
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