Global ETD Search

1	Towards a modern revision of the cyanobacteria, a critically important prokaryotic phylum / Towards a modern revision of the cyanobacteria, a critically important prokaryotic phylum BOHUNICKÁ, Markéta January 2015 (has links) With an adoption of modern methods of polyphasic approach to the study of cyanobacteria, an increased demand for the revision of the traditional taxonomy has emerged. This thesis is devoted to the systematic revisions of selected terrestrial cyanobacteria at several taxonomic levels. The methodology included thorough morphological characterization of cultured cyanobacterial strains using light and electron microscopy complemented with analyses of the molecular data: DNA sequencing, phylogenetic analyses based on 16S rRNA gene and the adjacent 16S-23S ITS region, and comparison of the predicted secondary structures of this region. Descriptions of new species, genera, families and an in-depth characterization of a previously poorly known family were achieved.
2	TAXONOMIC STUDIES AND THE EVOLUTION OF HABITAT PREFERENCE IN THE CYSTOBASIDIOMYCETES Pedro Pablo Parra Giraldo (7041446) 15 August 2019 (has links) Pucciniomycotina is a subphylum with a high diversity in terms of habitat and life history strategies that include plant parasites, animal associates (including opportunistic human pathogens), saprobes and antagonists of other fungi. The class Cystobasidiomycetes within this subphylum is a representative of such diversity and remains understudied. Their role in nature and the associations they establish with their hosts for most of the species is still unknown. In this study we used taxonomic and phylogenetic methods to present an inventory of strains in this class collected for more than 20 years from all over the world and preserved in the Aime Lab Culture Collection. Molecular and morphological data for six new species in the genera <i>Bannoa, Buckleyzyma</i>, <i>Halobasidium</i> and <i>Sakaguchia </i>were also presented. Additionally, mating experiments were performed by pairing strains of <i>Bannoa</i>; this is the second time in the genus that clamp connections and basidia are observed. We also found that newly described species of <i>Bannoa</i> can be co-inhabitants of sori of rust fungi. In general, antagonistic interactions can occur through: 1) direct physical contact between two fungi, i.e., mycoparasitism; or, 2) the production of antimicrobial compounds. In the Cystobasidiomycetes, direct physical antagonistic interaction which is associated with sexual states has been reported in species of Cystobasidium, Naohidea, Cyphobasidium and Occultifur. On the other hand, the production of antimicrobial compounds which mainly occurs between the yeast stage of the fungi and other organisms has only been reported in Cystobasidium pallidumand Hasegawazyma lactosa. We also hypothesize that the common ancestor to Cystobasidiomycetes is a mycoparasite due to the fact that this life strategy is present in most of the lineages in the class. To test this hypothesis, we grouped into five categories the host association or substrate from which strains of extant species in the Cystobasidiomycetes were isolated, i.e.,animals, plants, fungi, aquatic or decaying organic matter. We constructed a resolved phylogeny for the class based on seven locito study the evolutionary origins of mycoparasitism through ancestral character reconstruction with representation of all described species. Our analysis suggests that the most likely hypothesis is that the most recent common ancestor of the Cystobasidiomycetes was associated to fungi.<br> Sustainable Agricultural Development Cystobasidiomycetes pink yeasts Pucciniomycotina tropical fungi new taxa mycoparasitism
3	Small Vertebrates of the Bidahochi Formation, White Cone, Northeastern Arizona Baskin, Jon Alan January 1975 (has links) Two taxa of amphibians, five taxa of reptiles, and eighteen taxa of mammals were collected by screen-washing sediments from the upper Bidahochi Formation at White Cone peak, northeastern Arizona. Five new species of mammals were recovered. They include Perognathoides bidahochiensis (Heteromyidae), Bensonomys yazhi (Cricetidae), Bensonomys bradyi (Cricetidae), Paronychomys alticuspis (Cricetidae), and Martes (Plionictis) repenningi (Mustelidae). Bensonomys yazhi and Bensonomys bradyi are close to the stem of Central and South Americal hesperomyine radiation. The radiation began in the southwest United States and Mexico during the Hemphillian. The middle member of the Bidahochi Formation is dated at 6.7 m. y. by a basalt from Roberts Mesa. The paleomagnetic data and the White Cone local fauna support this middle Hemphillian date. Amphibia Arizona Bensonomys Bidahochi Formation Carnivora Cenozoic Chordata Cricetidae Eutheria faunal studies Hemphillian Heteromyidae Mammalia Martes Miocene Mustclidae Myomorpha Neogene new taxa northeast occurrence paleontology Perognathoides Pliocene radiation Reptilia Rodentia Tertiary Tetrapoda Theria United States Vertebrata White Cone Paleontology -- Arizona -- White Cone Vertebrates -- Arizona -- White Cone Vertebrates, Fossil

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