Sökning: "Biologiska institutionen"

Visar resultat 1 - 5 av 2389 avhandlingar innehållade orden Biologiska institutionen.

  1. 1. Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time

    Författare :Andrea Caputo; Rachel Ann Foster; Monika Quinones Winder; Ramon Massana; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; phytoplankton; diatoms; cyanobacteria; diazotrophs; symbiosis; evolution; phylogenetics; confocal microscopy; qPCR; CARD-FISH; tropics; sub-tropics; marin ekologi; Marine Ecology;

    Sammanfattning : Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. LÄS MER

  3. 2. Reproductive physiology of the female three-spined stickleback, Gasterosteus aculeatus

    Författare :Chrysoula Roufidou; Bertil Borg; Geir Lasse Taranger; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; overripening of eggs; spawning cycle; brain-pituitary-gonad BPG axis; vitellogenin; ovarian fluid; sex steroids; reproduction; three-spined stickleback; Gasterosteus aculeatus; fish; Functional Zoomorphology; funktionell zoomorfologi;

    Sammanfattning : Reproduction in vertebrates, including fishes, is under control of the brain-pituitary-gonad (BPG) axis. The female three-spined stickleback, Gasterosteus aculeatus, produces egg clutches at intervals of a few days and spawns them in a nest built by male. LÄS MER

  4. 3. Molecular Evolution of the Vertebrate Genome

    Författare :Kiwoong Nam; Hans Ellegren; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : In this thesis, I studied molecular evolution of the vertebrate genome, focusing on sex chromosomes, protein coding genes, and genome size variation. The evolutionary history of avian sex chromosomes was analyzed by comparing substitution rate among 12 gametologous gene pairs on the Z and W chromosomes. LÄS MER

  5. 4. Molecular mechanisms involved in prokaryotic cycling of labile dissolved organic matter in the sea

    Författare :Benjamin Pontiller; Jarone Pinhassi; Daniel Lundin; Catherine Legrand; Martin F. Polz; Linnéuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; Bacteria and archaea; labile dissolved organic matter; metatranscriptomics; monomers; polymers; carbohydrate-active enzymes CAZymes ; peptidases; membrane transporters; Natural Science; Naturvetenskap; Akvatisk ekologi; Aquatic Ecology; Mikrobiologi; Microbiology;

    Sammanfattning : Roughly half of the global primary production originates from microscopic phytoplankton in marine ecosystems, converting carbon dioxide into organic matter. This organic matter pool consists of a myriad of compounds that fuel heterotrophic bacterioplankton. LÄS MER

  7. 5. Evolutionary Dynamics of Mutation and Gene Transfer in Bacteria

    Författare :Peter A Lind; Dan I Andersson; J. Arjan G. M. de Visser; Uppsala universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; fitness cost; bacterial evolution; gene amplification; mutational biases; GC content; synonymous substitutions; horizontal gene transfer; experimental evolution; Bacteriology; Bakteriologi; Microbiology; Mikrobiologi; Genetics; Genetik; Biology; Biologi; Mikrobiologi; Microbiology;

    Sammanfattning : The study of bacterial evolution is fundamental for addressing current problems of antibiotic resistance and emerging infectious diseases and lays a solid foundation for successful and rational design in biotechnology and synthetic biology. The main aim of this thesis is to test evolutionary hypotheses, largely based on theoretical considerations and sequence analysis, by designing scenarios in a laboratory setting to obtain experimental data. LÄS MER