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Sökning: WFRF:(Divakar H)

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1.
  • Zamora, Juan Carlos, et al. (författare)
  • Considerations and consequences of allowing DNA sequence data as types of fungal taxa
  • 2018
  • Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
  • Tidskriftsartikel (refereegranskat)abstract
    • Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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2.
  • Schoch, CL, et al. (författare)
  • Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi
  • 2012
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 109:16, s. 6241-6246
  • Tidskriftsartikel (refereegranskat)abstract
    • Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.
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  • Smith, ER, et al. (författare)
  • Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis
  • 2023
  • Ingår i: BMJ global health. - : BMJ. - 2059-7908. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies.MethodsWe screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale.ResultsWe screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection—as compared with uninfected pregnant women—were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias.ConclusionsThis analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol.
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  • Crespo, Ana, et al. (författare)
  • Phylogenetic generic classification of parmelioid lichens (Parmeliaceae,Ascomycota) based on molecular, morphological and chemical evidence.
  • 2010
  • Ingår i: Taxon. - : John Wiley & Sons. - 0040-0262 .- 1996-8175. ; 59:6, s. 1735-1753
  • Tidskriftsartikel (refereegranskat)abstract
    • Parmelioid lichens are a diverse and ubiquitous group of foliose lichens. Generic delimitation in parmelioid lichens has been in a state of flux since the late 1960s with the segregation of the large, heterogeneous genus Parmelia into numerous smaller genera. Recent molecular phylogenetic studies have demonstrated that some of these new genera were monophyletic, some were not, and others, previously believed to be unrelated, fell within single monophyletic groups, indicating the need for a revision of the generic delimitations. This study aims to give an overview of current knowledge of the major clades of all parmelioid lichens. For this, we assembled a dataset of 762 specimens, including 31 of 33 currently accepted parmelioid genera (and 63 of 84 accepted genera of Parmeliaceae). We performed maximum likelihood and Bayesian analyses of combined datasets including two, three and four loci. Based on these phylogenies and the correlation of morphological and chemical characters that characterize monophyletic groups, we accept 27 genera within nine main clades. We re-circumscribe several genera and reduce Parmelaria to synonymy with Parmotrema. Emodomelanelia Divakar & A. Crespo is described as a new genus (type: E. masonii). Nipponoparmelia (Kurok.) K.H. Moon, Y. Ohmura & Kashiw. ex A. Crespo & al. is elevated to generic rank and 15 new combinations are proposed (in the genera Flavoparmelia, Parmotrema, Myelochroa, Melanelixia and Nipponoparmelia). A short discussion of the accepted genera is provided and remaining challenges and areas requiring additional taxon sampling are identified.
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  • Crespo, Ana, et al. (författare)
  • Testing morphology-based hypotheses of phylogenetic relationships in Parmeliaceae (Ascomycota) using three ribosomal markers and the nuclear RPB1 gene
  • 2007
  • Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 44:2, s. 812-824
  • Tidskriftsartikel (refereegranskat)abstract
    • Parmeliaceae is the largest family of lichen-forming fungi with more than 2000 species and includes taxa with different growth forms. Morphology was widely employed to distinguish groups within this large, cosmopolitan family. In this study we test these morphology-based groupings using DNA sequence data from three nuclear and one mitochondrial marker from 1.20 taxa that include 59 genera and represent the morphological and chemical diversity in this lineage. Parmeliaceae is strongly supported as monophyletic and six well-supported main clades can be distinguished within the family. The relationships among them remain unresolved. The clades largely agree with the morphology-based groupings and only the placement of four of the genera studied is rejected by molecular data, while four other genera belong to clades previously unrecognised. The classification of these previously misplaced genera, however, has already been questioned by some authors based on morphological evidence. These results support morphological characters as important for the identification of monophyletic clades within Parmeliaceae.
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10.
  • Divakar, Pradeep K., et al. (författare)
  • Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi
  • 2015
  • Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:4, s. 1217-1226
  • Tidskriftsartikel (refereegranskat)abstract
    • We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.
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11.
  • Nelsen, Matthew P., et al. (författare)
  • The cetrarioid core group revisited (Lecanorales: Parmeliaceae)
  • 2011
  • Ingår i: Lichenologist. - 0024-2829. ; 43:6, s. 537-551
  • Tidskriftsartikel (refereegranskat)abstract
    • The cetrarioid core group has been the focus of numerous taxonomic and phylogenetic studies in recent years, yet the phylogenetic resolution and support among these clades remains unclear. Here we use four commonly employed loci to estimate if their use increases phylogenetic resolution and support. The present study largely confirms the topologies of previous studies, but with increased support. Approximately half of the genera in the cetrarioid core were not monophyletic. Melanelia sorediella was clustered within Cetrariella, and the combination Cetrariella sorediella (Lettau) V. J. Rico & A. Thell comb. nov. is made. Additionally, the genus Flavocetrariella was supported as part of Nephromopsis and is considered to be a synonym of the latter. Finally, a comparison of genetic distances shows that the maximum intrageneric genetic distance encompassed by many cetrarioid genera is lower than that of many other genera in Parmeliaceae.
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13.
  • Schoch, Conrad L., et al. (författare)
  • Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi
  • 2014
  • Ingår i: Database: The Journal of Biological Databases and Curation. - : Oxford University Press (OUP). - 1758-0463. ; 2014:bau061, s. 1-21
  • Tidskriftsartikel (refereegranskat)abstract
    • 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. Re-annotated 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.
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  • Thell, Arne, et al. (författare)
  • A review of the lichen family Parmeliaceae - history, phylogeny and current taxonomy.
  • 2012
  • Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 30:6, s. 641-664
  • Tidskriftsartikel (refereegranskat)abstract
    • The largest family of lichen-forming fungi, the Parmeliaceae, is reviewed. It includes 79 genera in current use and ca 2726 species, a large majority of which belong to one of five main clades: the parmelioid, cetrarioid, usneoid, alectorioid and hypogymnioid. However, 21 genera are positioned outside these clades, and four genera in current use still lack DNA- data. The family has been shown to be monophyletic and the generic classification is relatively well-settled compared with other lecanoralean families. Each clade and its genera are presented here with the latest results from phylogenetic analyses and current taxonomy. In addition, a historical outline of the family and its most prominent researchers is provided.
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16.
  • Zhao, Xin, et al. (författare)
  • Towards a revised generic classification of lecanoroid lichens (Lecanoraceae, Ascomycota) based on molecular, morphological and chemical evidence
  • 2016
  • Ingår i: Fungal Diversity. - : Springer Science and Business Media LLC. - 1560-2745 .- 1878-9129. ; 78:1, s. 293-304
  • Tidskriftsartikel (refereegranskat)abstract
    • The phylogenetic relationship of lecanoroid lichens is studied using two data sets: 1) a 2-locus data set including 251 OTUs representing 150 species, and 2) a 6-locus data set with 82 OTUs representing 53 species. The genus Lecanora as currently circumscribed is shown to be highly polyphyletic and several genera, including Adelolecia, Arctopeltis, Bryonora, Carbonea, Frutidella, Lecidella, Miriquidica, Palicella, Protoparmeliopsis, Pyrrhospora, and Rhizoplaca are nested within Lecanora sensu lato. A core group of Lecanora is supported as monophyletic and includes species of the L. carpinea, L. rupicola, and L. subcarnea groups, and a core group of the L. subfusca group. Three monophyletic clades that are well supported in our analyses and well characterized by phenotypical characters are accepted here: 1) Myriolecis to accommodate the Lecanora dispersa group and Arctopeltis; 2) Protoparmeliopsis for the L. muralis group; and 3) Rhizoplaca is emended to include three placodioid taxa previously classified in Lecanora (L. novomexicana. L. opiniconensis, L. phaedrophthalma), whereas R. aspidophora and R. peltata are excluded from Rhizoplaca. The latter is transferred into Protoparmeliopsis. Lecidella is strongly supported as a monophyletic group. Our studies indicate the presence of additional clades of species currently placed in Lecanora sensu lato that warrant taxonomic recognition but additional data will be necessary before the circumscription of these entities is fully understood. 37 new combinations are proposed into the genera Myriolecis (30), Protoparmeliopsis (2), and Rhizoplaca (5).
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