Project description:The Dothideomycetes are a class of cosmopolitan fungi that are present principally in terrestrial environments, but which have also been found in freshwater and marine habitats. In the present study, more than a hundred samples of plant debris were collected from various freshwater locations in Spain. Its incubation in wet chambers allowed us to detect and to isolate in pure culture numerous fungi producing asexual reproductive fruiting bodies (conidiomata). Thanks to a morphological comparison and to a phylogenetic analysis that combined the internal transcribed spacer (ITS) region of the nrDNA with fragments of the RNA polymerase II subunit 2 (rpb2), beta tubulin (tub2), and the translation elongation factor 1-alpha (tef-1) genes, six of those strains were identified as new species to science. Three belong to the family Didymellaceae: Didymella brevipilosa, Heterophoma polypusiformis and Paraboeremia clausa; and three belong to the family Phaeosphaeriaceae:Paraphoma aquatica, Phaeosphaeria fructigena and Xenophoma microspora. The finding of these new taxa significantly increases the number of the coelomycetous fungi that have been described from freshwater habitats.
Project description:With the exception of the so-called Ingoldian fungi, the diversity and distribution of the freshwater aero-aquatic or facultative fungi are not well known in Spain. In view of that, we collected and placed into wet chambers 105 samples of submerged and decomposing plant debris from various places in Spain, looking for individuals belonging to these latter two morpho-ecological groups of fungi. As a result, we found and isolated in pure culture several fungi, the morphology of some of them belonging to the family Amniculicolaceae (order Pleosporales, class Dothideomycetes). After a careful phenotypic characterization and a phylogenetic tree reconstruction using a concatenated sequence dataset of D1-D2 domains of the 28S nrRNA gene (LSU), the internal transcribed spacer region (ITS) of the nrDNA, and a fragment of the translation elongation factor 1-alpha (tef1) gene, we report the finding of three new species of the genus Murispora: Murispora navicularispora, which produces cinnamon-colored, broadly fusiform to navicular ascospores; Murispora fissilispora, which has as a remarkable characteristic the production of both sexual and asexual morphs in vitro; and Murispora asexualis, the unique species of the genus that lacks a sexual morph. As a consequence of the phylogenetic study, we introduce the new aero-aquatic genus Fouskomenomyces, with a new combination (Fouskomenomyces cupreorufescens, formerly Spirosphaera cupreorufescens as the type species of the genus) and a new species, Fouskomenomyces mimiticus; we propose the new combinations Murispora bromicola (formerly Pseudomassariosphaeria bromicola) and Murispora triseptata (formerly Pseudomassariosphaeria triseptata); and we resurrect Massariosphaeria grandispora, which is transferred to the family Lopiostomataceae.
Project description:The freshwater Dothideomycetes species are an ecological rather than taxonomic group and comprise approximately 178 meiosporic and mitosporic species. Due to convergent or parallel morphological adaptations to aquatic habitats, it is difficult to determine phylogenetic relationships among freshwater taxa and among freshwater, marine and terrestrial taxa based solely on morphology. We conducted molecular sequence-based phylogenetic analyses using nuclear ribosomal sequences (SSU and/or LSU) for 84 isolates of described and undescribed freshwater Dothideomycetes and 85 additional taxa representative of the major orders and families of Dothideomycetes. Results indicated that this ecological group is not monophyletic and all the freshwater taxa, except three aeroaquatic Tubeufiaceae, occur in Pleosporomycetidae as opposed to Dothideomycetidae. Four clades comprised of only freshwater taxa were recovered. The largest of these is the Jahnulales clade consisting of 13 species, two of which are the anamorphs Brachiosphaera tropicalis and Xylomyces chlamydosporus. The second most speciose clade is the Lindgomycetaceae clade consisting of nine taxa including the anamorph Taeniolella typhoides. The Lindgomycetaceae clade consists of taxa formerly described in Massarina, Lophiostoma, and Massariosphaeriae.g.,Massarina ingoldiana, Lophiostoma breviappendiculatum, and Massariosphaeria typhicola and several newly described and undescribed taxa. The aquatic family Amniculicolaceae, including three species of Amniculicola, Semimassariosphaeria typhicola and the anamorph, Anguillospora longissima, was well supported. A fourth clade of freshwater species consisting of Tingoldiago graminicola,Lentithecium aquaticum,L. arundinaceum and undescribed taxon A-369-2b was not well supported with maximum likelihood bootstrap and Bayesian posterior probability. Eight freshwater taxa occurred along with terrestrial species in the Lophiostoma clades 1 and 2. Two taxa lacking statistical support for their placement with any taxa included in this study are considered singletons within Pleosporomycetidae. These singletons, Ocala scalariformis, and Lepidopterella palustris, are morphologically distinct from other taxa in Pleosporomycetidae. This study suggests that freshwater Dothideomycetes are related to terrestrial taxa and have adapted to freshwater habitats numerous times. In some cases (Jahnulales and Lindgomycetaceae), species radiation appears to have occurred. Additional collections and molecular study are required to further clarify the phylogeny of this interesting ecological group.
Project description:WE PRESENT AN UPDATED LIST OF TERRESTRIAL AND FRESHWATER NEMATODES FROM ALL REGIONS OF THE ARCTIC, FOR WHICH RECORDS OF PROPERLY IDENTIFIED NEMATODE SPECIES ARE AVAILABLE: Svalbard, Jan Mayen, Iceland, Greenland, Nunavut, Northwest territories, Alaska, Lena River estuary, Taymyr and Severnaya Zemlya and Novaya Zemlya. The list includes 391 species belonging to 146 genera, 54 families and 10 orders of the phylum Nematoda.
Project description:Coelomycetous fungi are ubiquitous in soil, sewage, and sea- and freshwater environments. However, freshwater coelomycetous fungi have been very rarely reported in the literature. Knowledge of coelomycetous fungi in freshwater habitats in Spain is poor. The incubation of plant debris, from freshwater in various places in Spain into wet chambers, allowed us to detect and isolate in pure culture several pycnidia-producing fungi. Fungal strains were phenotypically characterized, and a phylogenetic study was carried out based on the analysis of concatenated nucleotide sequences of the D1-D2 domains of the 28S nrRNA gene (LSU), the internal transcribed spacer region (ITS) of the nrDNA, and fragments of the RNA polymerase II subunit 2 (rpb2) and beta tubulin (tub2) genes. As a result of these, we report the finding of two novel species of Neocucurbitaria, three of Neopyrenochaeta, and one of Pyrenochaetopsis. Based on the phylogenetic study, we also transferred Neocucurbitaria prunicola to the genus Allocucurbitaria. This work makes an important contribution to the knowledge of the mycobiota of plant debris in freshwater habitats.
Project description:Microcystins (MCs) are cyclic heptapeptides, which are the most abundant toxins produced by cyanobacteria in freshwater. The phytoplankton of many freshwater lakes in Eastern Africa is dominated by cyanobacteria. Less is known, however, on the occurrence of MC producers and the production of MCs. Twelve Ugandan freshwater habitats ranging from mesotrophic to hypertrophic conditions were sampled in May and June of 2004 and April of 2008 and were analyzed for their physicochemical parameters, phytoplankton composition, and MC concentrations. Among the group of the potential MC-producing cyanobacteria, Anabaena (0-10(7) cells ml(-1)) and Microcystis (10(3)-10(7) cells ml(-1)) occurred most frequently and dominated in eutrophic systems. A significant linear relationship (n = 31, r(2) = 0.38, P < 0.001) between the Microcystis cell numbers and MC concentration (1.3-93 fg of MC cell(-1)) was observed. Besides [MeAsp(3), Mdha(7)]-MC-RR, two new MCs, [Asp(3)]-MC-RY and [MeAsp(3)]-MC-RY, were isolated and their constitution was assigned by LC-MS(2). To identify the MC-producing organism in the water samples, (i) the conserved aminotransferase domain part of the mcyE gene that is indicative of MC production was amplified by general primers and cloned and sequenced, and (ii) genus-specific primers were used to amplify the mcyE gene of the genera Microcystis, Anabaena, and Planktothrix. Only mcyE genotypes that are indicative of Microcystis sp. were obtained via the environmental cloning approach (337 bp, 96.1-96.7% similarity to the Microcystis aeruginosa strain PCC7806). Accordingly, only the mcyE primers, which are specific for Microcystis, revealed PCR products. We concluded that Microcystis is the major MC-producer in Ugandan freshwater.