21 research outputs found

    Outline of Fungi and fungus-like taxa

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    This article provides an outline of the classification of the kingdom Fungi (including fossil fungi. i.e. dispersed spores, mycelia, sporophores, mycorrhizas). We treat 19 phyla of fungi. These are Aphelidiomycota, Ascomycota, Basidiobolomycota, Basidiomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Entorrhizomycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. The placement of all fungal genera is provided at the class-, order- and family-level. The described number of species per genus is also given. Notes are provided of taxa for which recent changes or disagreements have been presented. Fungus-like taxa that were traditionally treated as fungi are also incorporated in this outline (i.e. Eumycetozoa, Dictyosteliomycetes, Ceratiomyxomycetes and Myxomycetes). Four new taxa are introduced: Amblyosporida ord. nov. Neopereziida ord. nov. and Ovavesiculida ord. nov. in Rozellomycota, and Protosporangiaceae fam. nov. in Dictyosteliomycetes. Two different classifications (in outline section and in discussion) are provided for Glomeromycota and Leotiomycetes based on recent studies. The phylogenetic reconstruction of a four-gene dataset (18S and 28S rRNA, RPB1, RPB2) of 433 taxa is presented, including all currently described orders of fungi

    Polyphasic taxonomy of fungi: the concept, methods and examples

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    Polyphasic approach is a relatively new and interesting taxonomic practice. At this time we observe an attempt to combine taxonomy based on molecular phylogeny and on complex phenotypic analysis. Many different types of characters can be used for phenotypic analysis: morphological, genetic, chemical and so on. Further development of theoretic basis of the polyphasic approach is needed. Methods of fungal metabolite analysis and hierarchy of characters should be improved as well.Работа выполнена при финансовой поддержке РНФ (проект 14–26–00067)

    Species of the genus Ulocladium Preuss in Russia: morphological characters and their use for identification purposes

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    Three species of the Ulocladium genus were identified (U. chartarum, U. septosporum, U. botrytis) among Russian isolates using classical morphological features. Isolates of U. botrytis produced colonies of two types. A number of cultural parameters (colony colour, presence of strips surrounding colony and concentric rings, type of colony edge, colony back surface colour, presence and type of chaps) can be used as additional characters for species identification.Работа выполнена при финансовой поддержке РНФ (проект 14–26–00067)

    Radiogenic helium isotope fractionation: the role of tritium as 3He precursor in geochemical applications

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    Reduced 4He/3He ratios, e.g., down to ≈1/100 times those expected from radiogenic production, were observed in sedimentary rocks. Formation and history of these rocks eliminate a contribution of mantle 3He-bearing fluid. To explain the difference between the observed and the calculated production 4He/3He ratios Loosli et al. (1995) and Tolstikhin et al. (1996) suggested a different behaviour of helium and tritium in damage tracks produced by emission of these nuclides. Generally, the tracks cross grain boundaries or some imperfections within a rock or mineral allowing a fast loss of noble 4He and 3He atoms. However, radiogenic 3He has the precursor 3H, generated in the exothermic 6Li(nt, α)3H + 4.5 MeV reaction. The energetic tritons produce damage tracks comparable with those from α-decay of U and Th series. If 3H is chemically bound within a track, and the track is able to recover via some diagenetic process before the 3H decay, then 3H and daughter 3He atoms are trapped within the recovered track. This mechanism would explain the shorter residence time of 4He in the rocks/minerals than of 3He; therefore, 4He/3He ratios could decrease through time. To check this mechanism 4He, 3H, and 3He (from 3H-decay) were produced by the above reaction in special targets, consisting of layered composites of thin sections of quartz, sample, Li-bearing cover, sample, and quartz. The samples were the same rocks in which reduced 4He/3He ratios have been previously observed. Each target was placed in a quartz ampoule, which was then pumped out, sealed off, and then exposed to the flux of thermal neutrons in a reactor. After irradiation and cooling down (total duration 145 days), the nuclides produced during (3H, 3He, 4He) and after (3He) irradiation were measured in the gas phase above the targets and compared with their total quantities expected from the Li abundance and the integrated neutron flux. The ratios obtained were 3H(gas)/3H(total) < 0.05 and 3He(gas)/3He(total) varying from 0.2 to 0.9. The average residence times τ of 3H and 3He, respectively, were estimated to be ≈16 and ≈0.25 yr for this first time interval, which included the irradiation of the targets. After these first measurements, the targets were kept in a vacuum system under room temperature for 210 days and the amounts of 3H and 3He, which accumulated above the targets during this second time interval under fully controlled conditions, were also measured. Much slower rates of gas loss from the same targets with average residence times of τ(3H) ≈ 600 yr and τ(He) ≈ 1.6 yr resulted for this second time interval. Probably these longer residence times are closer to those in the relevant natural environments, the 3H residence time being much longer than the 3H half-life. In all cases the inequality τ(3He) ≪ τ(3H) is valid. This confirms the proposed scenario envisaging longer retention of 3H than He in damage tracks. Within the frame of this scenario the life-time of 3H gives a time constraint on diagenetic processes; at least one to several newly formed atomic layers should appear during ∼10 yr to recover the tracks

    An Early Proterozoic U-Pb zircon age from an Eskolabreen Formation gneiss in southern Ny Friesland, Spitsbergen

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    A preliminary U/Pb zircon age determination has been carried out on a grey gneiss of the Eskolabreen Formation, the lowest observable lithostratigraphic unit of Precambrian metamorphic rocks in southern Ny Friesland, NE Spitsbergen. The obtained age, ca. 2, 400 Ma, is considered to be a metamorphic age and suggests an Early Proterozoic tectonothermal event
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