64 research outputs found
Accurate Identification of Closely Related Mycobacterium tuberculosis Complex Species by High Resolution Tandem Mass Spectrometry
Rapid and accurate differentiation of Mycobacterium tuberculosis complex (MTBC) species from other mycobacterium is essential for appropriate therapeutic management, timely intervention for infection control and initiation of appropriate health care measures. However, routine clinical characterization methods for Mycobacterium tuberculosis (Mtb) species remain both, time consuming and labor intensive. In the present study, an innovative liquid Chromatography-Mass Spectrometry method for the identification of clinically most relevant Mycobacterium tuberculosis complex species is tested using a model set of mycobacterium strains. The methodology is based on protein profiling of Mycobacterium tuberculosis complex isolates, which are used as markers of differentiation. To test the resolving power, speed, and accuracy of the method, four ATCC type strains and 37 recent clinical isolates of closely related species were analyzed using this new approach. Using different deconvolution algorithms, we detected hundreds of individual protein masses, with a subpopulation of these functioning as species-specific markers. This assay identified 216, 260, 222, and 201 proteoforms for M. tuberculosis ATCC 27294™, M. microti ATCC 19422™, M. africanum ATCC 25420™, and M. bovis ATCC 19210™ respectively. All clinical strains were identified to the correct species with a mean of 95% accuracy. Our study successfully demonstrates applicability of this novel mass spectrometric approach to identify clinically relevant Mycobacterium tuberculosis complex species that are very closely related and difficult to differentiate with currently existing methods. Here, we present the first proof-of-principle study employing a fast mass spectrometry-based method to identify the clinically most prevalent species within the Mycobacterium tuberculosis species complex
50 years of Emmonsia disease in humans: the dramatic emergence of a cluster of novel fungal pathogens
New species of Emmonsia-like fungi, with phylogenetic and clinical similarities to Blastomyces and Histoplasma, have emerged as causes of systemic human mycoses worldwide. They differ from classical Emmonsia species by producing a thermally-dependent, yeast-like phase rather than adiaspores, and by causing disseminated infections, predominantly in immunocompromised patients and often with high case-fatality rates. Such differences will be important for clinicians to consider in diagnosis and patient management, and for microbiologists who may encounter these fungi with increasing frequency
Genomic Understanding of an Infectious Brain Disease from the Desert
Rhinocladiella mackenziei accounts for the majority of fungal brain infections in the Middle East, and
is restricted to the arid climate zone between Saudi Arabia and Pakistan. Neurotropic dissemination caused by this
fungus has been reported in immunocompromised, but also immunocompetent individuals. If untreated, the
infection is fatal. Outside of humans, the environmental niche of R. mackenziei is unknown, and the fungus has
been only cultured from brain biopsies. In this paper, we describe the whole-genome resequencing of two R.
mackenziei strains from patients in Saudi Arabia and Qatar. We assessed intraspecies variation and genetic
signatures to uncover the genomic basis of the pathogenesis, and potential niche adaptations. We found that
the duplicated genes (paralogs) are more susceptible to accumulating significant mutations. Comparative genomics with other filamentous ascomycetes revealed a diverse arsenal of genes likely engaged in pathogenicity, such
as the degradation of aromatic compounds and iron acquisition. In addition, intracellular accumulation of trehalose
and choline suggests possible adaptations to the conditions of an arid climate region. Specifically, protein family
contractions were found, including short-chain dehydrogenase/reductase SDR, the cytochrome P450 (CYP)
(E-class), and the G-protein b WD-40 repeat. Gene composition and metabolic potential indicate extremotolerance
and hydrocarbon assimilation, suggesting a possible environmental habitat of oil-polluted desert soilinfo:eu-repo/semantics/publishedVersio
Codivergence of Mycoviruses with Their Hosts
BACKGROUND: The associations between pathogens and their hosts are complex and can result from any combination of evolutionary events such as codivergence, switching, and duplication of the pathogen. Mycoviruses are RNA viruses which infect fungi and for which natural vectors are so far unknown. Thus, lateral transfer might be improbable and codivergence their dominant mode of evolution. Accordingly, mycoviruses are a suitable target for statistical tests of virus-host codivergence, but inference of mycovirus phylogenies might be difficult because of low sequence similarity even within families. METHODOLOGY: We analyzed here the evolutionary dynamics of all mycovirus families by comparing virus and host phylogenies. Additionally, we assessed the sensitivity of the co-phylogenetic tests to the settings for inferring virus trees from their genome sequences and approximate, taxonomy-based host trees. CONCLUSIONS: While sequence alignment filtering modes affected branch support, the overall results of the co-phylogenetic tests were significantly influenced only by the number of viruses sampled per family. The trees of the two largest families, Partitiviridae and Totiviridae, were significantly more similar to those of their hosts than expected by chance, and most individual host-virus links had a significant positive impact on the global fit, indicating that codivergence is the dominant mode of virus diversification. However, in this regard mycoviruses did not differ from closely related viruses sampled from non-fungus hosts. The remaining virus families were either dominated by other evolutionary modes or lacked an apparent overall pattern. As this negative result might be caused by insufficient taxon sampling, the most parsimonious hypothesis still is that host-parasite evolution is basically the same in all mycovirus families. This is the first study of mycovirus-host codivergence, and the results shed light not only on how mycovirus biology affects their co-phylogenetic relationships, but also on their presumable host range itself
The genera of fungi-fixing the application of the type species of generic names-G 2: Allantophomopsis, Latorua, Macrodiplodiopsis, Macrohilum, Milospium, Protostegia, Pyricularia, Robillarda, Rotula, Septoriella, Torula, and Wojnowicia
The present paper represents the second contribution in the Genera of Fungi series, linking type species
of fungal genera to their morphology and DNA sequence data, and where possible, ecology. This paper focuses on
12 genera of microfungi, 11 of which the type species are neo- or epitypified here: Allantophomopsis (A. cytisporea,
Phacidiaceae, Phacidiales, Leotiomycetes), Latorua gen. nov. (Latorua caligans, Latoruaceae, Pleosporales,
Dothideomycetes), Macrodiplodiopsis (M. desmazieri, Macrodiplodiopsidaceae, Pleosporales, Dothideomycetes),
Macrohilum (M. eucalypti, Macrohilaceae, Diaporthales, Sordariomycetes), Milospium (M. graphideorum,
incertae sedis, Pezizomycotina), Protostegia (P. eucleae, Mycosphaerellaceae, Capnodiales, Dothideomycetes),
Pyricularia (P. grisea, Pyriculariaceae, Magnaporthales, Sordariomycetes), Robillarda (R. sessilis, Robillardaceae,
Xylariales, Sordariomycetes), Rutola (R. graminis, incertae sedis, Pleosporales, Dothideomycetes), Septoriella
(S. phragmitis, Phaeosphaeriaceae, Pleosporales, Dothideomycetes), Torula (T. herbarum, Torulaceae,
Pleosporales, Dothideomycetes) and Wojnowicia (syn. of Septoriella, S. hirta, Phaeosphaeriaceae, Pleosporales,
Dothideomycetes). Novel species include Latorua grootfonteinensis, Robillarda africana, R. roystoneae, R. terrae,
Torula ficus, T. hollandica, and T. masonii spp. nov., and three new families: Macrodiplodiopsisceae, Macrohilaceae,
and Robillardaceae. Authors interested in contributing accounts of individual genera to larger multi-authored papers
to be published in IMA Fungus, should contact the associate editors listed for the major groups of fungi on the List
of Protected Generic Names for FungiThe Austrian
Science Fund (FWF; project P25870-B16)http://www.generaoffungi.orgam201
Species Delimitation in Taxonomically Difficult Fungi: The Case of Hymenogaster
False truffles are ecologically important as mycorrhizal partners of trees and evolutionarily highly interesting as the result of a shift from epigeous mushroom-like to underground fruiting bodies. Since its first description by Vittadini in 1831, inappropriate species concepts in the highly diverse false truffle genus Hymenogaster has led to continued confusion, caused by a large variety of prevailing taxonomical opinions.In this study, we reconsidered the species delimitations in Hymenogaster based on a comprehensive collection of Central European taxa comprising more than 140 fruiting bodies from 20 years of field work. The ITS rDNA sequence dataset was subjected to phylogenetic analysis as well as clustering optimization using OPTSIL software.Among distinct species concepts from the literature used to create reference partitions for clustering optimization, the broadest concept resulted in the highest agreement with the ITS data. Our results indicate a highly variable morphology of H. citrinus and H. griseus, most likely linked to environmental influences on the phenology (maturity, habitat, soil type and growing season). In particular, taxa described in the 19(th) century frequently appear as conspecific. Conversely, H. niveus appears as species complex comprising seven cryptic species with almost identical macro- and micromorphology. H. intermedius and H. huthii are described as novel species, each of which with a distinct morphology intermediate between two species complexes. A revised taxonomy for one of the most taxonomically difficult genera of Basidiomycetes is proposed, including an updated identification key. The (semi-)automated selection among species concepts used here is of importance for the revision of taxonomically problematic organism groups in general
Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits
Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild. Mycorrhizal symbioses have evolved repeatedly in diverse fungal lineages. A large phylogenomic analysis sheds light on genomic changes associated with transitions from saprotrophy to symbiosis, including divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.Peer reviewe
Finding needles in haystacks:Linking scientific names, reference specimens and molecular data for Fungi
DNA phylogenetic comparisons have shown that morphology-based species recognition
often underestimates fungal diversity. Therefore, the need for accurate DNA sequence
data, tied to both correct taxonomic names and clearly annotated specimen data, has
never been greater. Furthermore, the growing number of molecular ecology and microbiome
projects using high-throughput sequencing require fast and effective methods for
en masse species assignments. In this article, we focus on selecting and re-annotating a
set of marker reference sequences that represent each currently accepted order of Fungi.
The particular focus is on sequences from the internal transcribed spacer region in the
nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Reannotated
and verified sequences were deposited in a curated public database at the
National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci
(RTL) database, and will be visible during routine sequence similarity searches with
NR_prefixed accession numbers. A set of standards and protocols is proposed to improve
the data quality of new sequences, and we suggest how type and other reference
sequences can be used to improve identification of Fungi.The Intramural Research Programs
of the National Center for Biotechnology Information, National
Library of Medicine and the National Human Genome Research
Institute, both at the National Institutes of Health.http://www.ncbi.nlm.nih.gov/bioproject/PRJNA177353am201
Finding needles in haystacks : linking scientific names, reference specimens and molecular data for Fungi
DNA phylogenetic comparisons have shown that morphology-based species recognition
often underestimates fungal diversity. Therefore, the need for accurate DNA sequence
data, tied to both correct taxonomic names and clearly annotated specimen data, has
never been greater. Furthermore, the growing number of molecular ecology and microbiome
projects using high-throughput sequencing require fast and effective methods for
en masse species assignments. In this article, we focus on selecting and re-annotating a
set of marker reference sequences that represent each currently accepted order of Fungi.
The particular focus is on sequences from the internal transcribed spacer region in the
nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Reannotated
and verified sequences were deposited in a curated public database at the
National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci
(RTL) database, and will be visible during routine sequence similarity searches with
NR_prefixed accession numbers. A set of standards and protocols is proposed to improve
the data quality of new sequences, and we suggest how type and other reference
sequences can be used to improve identification of Fungi.The Intramural Research Programs
of the National Center for Biotechnology Information, National
Library of Medicine and the National Human Genome Research
Institute, both at the National Institutes of Health.http://www.ncbi.nlm.nih.gov/bioproject/PRJNA177353am201
Post-translational changes in Phialophora verrucosa via lysine lactylation during prolonged presence in a patient with a CARD9-related immune disorder
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