90 research outputs found

    New Species of Phoradendron (Viscaceae) from Mexico and Guatemala and a Synopsis of Species in Section Pauciflorae

    Get PDF
    As presently interpreted Phoradendron section Paucifiorae consists of 15 species. These mistletoes parasitize primarily conifers. We describe seven new species, make status changes for four species, and provide information on the hosts and distribution of all members of the section. New species described are: Phoradendron abietinurn Wiens, on Abies durangensi s in Chihuahua, Durango, and Jalisco, Mexico; P. acuminatum Wiens, on Cupressus lusitanica in Guatemala; P. flavomarginatum Wiens, on Juniperus fiaccida in Nuevo León, Mexico; P. lta wksworthii Wiens, on Juniperus in New Mexico, west Texas, and Coahuila, Mexico; P. olivae Wiens, on Cupressus lusitanica in Colima and Jalisco, Mexico; P. rufescens Wiens, on Juniperus spp . in San Luis Potosí, Mexico; and P. sedifolium Wiens on Cupressus lusitanica in Chiapas, and Hidalgo, Mexico. Three taxa previously recognized as subspecies are raised to specific rank: P. densum Torr. ex Trel., P. paucifiorum Torr., and P. libocedri (Engelm.) Howell. Also P. saltillense Trel., which had been placed in synonymy under P. botleanum subsp. densum, is accorded species status. In addition, three new epiparastic species of Phoradendron are described. Epiparastic mistletoes are known to parasitize only other species of mistletoes—in this instance Phoradendron or Cladocolea (Loranthaceae)

    The Numbers Behind Mushroom Biodiversity

    Get PDF
    Fungi are among the most diverse groups of organisms on Earth. with a global diversity estimated at 0.8 million to 5.1 million species. They play fundamental ecological roles as decomposers, mutualists, and pathogens, growing in almost all habitats and being important as sources of food and health benefits, income, and to maintain forest health. Global assessment of wild edible fungi indicate the existence of 2327 useful wild species; 2166 edible and 1069 used as food; 470 medicinal species. Several million tonnes are collected, consumed, and sold each year in over 80 countries. The major mushroom-producing countries in 2012 were China, Italy, USA, and The Netherlands, with 80% of the world production, 64% of which came from China. The European Union produces 24% of the world production. Italy is the largest European producer, Poland is the largest exporter, UK the largest importer.Fungi are difficult to preserve and fossilize and due to the poor preservation of most fungal structures, it has been difficult to interpret the fossil record of fungi. Hyphae, the vegetative bodies of fungi, bear few distinctive morphological characteristicss, and organisms as diverse as cyanobacteria, eukaryotic algal groups, and oomycetes can easily be mistaken for them (Taylor & Taylor 1993). Fossils provide minimum ages for divergences and genetic lineages can be much older than even the oldest fossil representative found. According to Berbee and Taylor (2010), molecular clocks (conversion of molecular changes into geological time) calibrated by fossils are the only available tools to estimate timing of evolutionary events in fossil‐poor groups, such as fungi. The arbuscular mycorrhizal symbiotic fungi from the division Glomeromycota, generally accepted as the phylogenetic sister clade to the Ascomycota and Basidiomycota, have left the most ancient fossils in the Rhynie Chert of Aberdeenshire in the north of Scotland (400 million years old). The Glomeromycota and several other fungi have been found associated with the preserved tissues of early vascular plants (Taylor et al. 2004a). Fossil spores from these shallow marine sediments from the Ordovician that closely resemble Glomeromycota spores and finely branched hyphae arbuscules within plant cells were clearly preserved in cells of stems of a 400 Ma primitive land plant, Aglaophyton, from Rhynie chert 455–460 Ma in age (Redecker et al. 2000; Remy et al. 1994) and from roots from the Triassic (250–199 Ma) (Berbee & Taylor 2010; Stubblefield et al. 1987).info:eu-repo/semantics/publishedVersio

    De novo Assembly of a 40 Mb Eukaryotic Genome from Short Sequence Reads: Sordaria macrospora, a Model Organism for Fungal Morphogenesis

    Get PDF
    Filamentous fungi are of great importance in ecology, agriculture, medicine, and biotechnology. Thus, it is not surprising that genomes for more than 100 filamentous fungi have been sequenced, most of them by Sanger sequencing. While next-generation sequencing techniques have revolutionized genome resequencing, e.g. for strain comparisons, genetic mapping, or transcriptome and ChIP analyses, de novo assembly of eukaryotic genomes still presents significant hurdles, because of their large size and stretches of repetitive sequences. Filamentous fungi contain few repetitive regions in their 30–90 Mb genomes and thus are suitable candidates to test de novo genome assembly from short sequence reads. Here, we present a high-quality draft sequence of the Sordaria macrospora genome that was obtained by a combination of Illumina/Solexa and Roche/454 sequencing. Paired-end Solexa sequencing of genomic DNA to 85-fold coverage and an additional 10-fold coverage by single-end 454 sequencing resulted in ∼4 Gb of DNA sequence. Reads were assembled to a 40 Mb draft version (N50 of 117 kb) with the Velvet assembler. Comparative analysis with Neurospora genomes increased the N50 to 498 kb. The S. macrospora genome contains even fewer repeat regions than its closest sequenced relative, Neurospora crassa. Comparison with genomes of other fungi showed that S. macrospora, a model organism for morphogenesis and meiosis, harbors duplications of several genes involved in self/nonself-recognition. Furthermore, S. macrospora contains more polyketide biosynthesis genes than N. crassa. Phylogenetic analyses suggest that some of these genes may have been acquired by horizontal gene transfer from a distantly related ascomycete group. Our study shows that, for typical filamentous fungi, de novo assembly of genomes from short sequence reads alone is feasible, that a mixture of Solexa and 454 sequencing substantially improves the assembly, and that the resulting data can be used for comparative studies to address basic questions of fungal biology

    Assessment of Night Vision Problems in Patients with Congenital Stationary Night Blindness

    Get PDF
    Congenital Stationary Night Blindness (CSNB) is a retinal disorder caused by a signal transmission defect between photoreceptors and bipolar cells. CSNB can be subdivided in CSNB2 (rod signal transmission reduced) and CSNB1 (rod signal transmission absent). The present study is the first in which night vision problems are assessed in CSNB patients in a systematic way, with the purpose of improving rehabilitation for these patients. We assessed the night vision problems of 13 CSNB2 patients and 9 CSNB1 patients by means of a questionnaire on low luminance situations. We furthermore investigated their dark adapted visual functions by the Goldmann Weekers dark adaptation curve, a dark adapted static visual field, and a two-dimensional version of the ‘‘Light Lab’’. In the latter test, a digital image of a living room with objects was projected on a screen. While increasing the luminance of the image, we asked the patients to report on detection and recognition of objects. The questionnaire showed that the CSNB2 patients hardly experienced any night vision problems, while all CSNB1 patients experienced some problems although they generally did not describe them as severe. The three scotopic tests showed minimally to moderately decreased dark adapted visual functions in the CSNB2 patients, with differences between patients. In contrast, the dark adapted visual functions of the CSNB1 patients were more severely affected, but showed almost no differences between patients. The results from the ‘‘2D Light Lab’’ showed that all CSNB1 patients were blind at low intensities (equal to starlight), but quickly regained vision at higher intensities (full moonlight). Just above their dark adapted thresholds both CSNB1 and CSNB2 patients had normal visual fields. From the results we conclude that night vision problems in CSNB, in contrast to what the name suggests, are not conspicuous and generally not disabling

    Arceuthobium douglasii in Nevada and Wyoming

    No full text
    Volume: 18Start Page: 63End Page: 6

    ABNORMAL FRUITS AND SEEDS IN ARCEUTHOBIUM

    No full text
    Volume: 16Start Page: 96End Page: 10

    Two new species, nomenclatural changes, and range extensions in Mexican Arceuthobium (Viscaceae)

    No full text
    Volume: 66Start Page: 5End Page: 1

    Change in Status of a Dwarf Mistletoe (Arceuthobium, Viscaceae) from China

    No full text
    Volume: 3Start Page: 156End Page: 15

    Pinyons of the Chihuahuan Desert region

    No full text
    Volume: 44Start Page: 129End Page: 13
    corecore