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Now showing 1 - 5 of 9
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    Good vs complementary genes for parasite resistance and the evolution of mate choice
    ( 2004-11-19) Howard, R Stephen ; Lively, Curtis M
    Background: Female mate choice may be adaptive when males exhibit heritable genetic variation at loci encoding resistance to infectious disease. The Hamilton-Zuk hypothesis predicts that females should assess the genetic quality of males by monitoring traits that indicate health and vigor (condition-dependent choice, or CD). Alternatively, some females may employ a more direct method of screening and select mates based on the dissimilarity of alleles at the major histocompatibility loci (we refer to this as opposites-attract, or OA). Empirical studies suggest that both forms of mate choice exist, but little is known about the potential for natural selection to shape the two strategies in nature.
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    Dual roles for ubiquitination in the processing of sperm organelles after fertilization
    ( 2014-02-10) Hajjar, Connie ; Sampuda, Katherine M ; Boyd, Lynn
    Background: The process of fertilization involves a cell fusion event between the sperm and oocyte. Although sperm contain mitochondria when they fuse with the oocyte, paternal mitochondrial genomes do not persist in offspring and, thus, mitochondrial inheritance is maternal in most animals. Recent evidence suggests that paternal mitochondria may be eliminated via autophagy after fertilization. In C. elegans, sperm-specific organelles called membraneous organelles (MO) cluster together with paternal mitochondria immediately after fertilization. These MOs but not the mitochondria become polyubiquitinated and associated with proteasomes. The current model for the elimination of paternal mitochondria in C. elegans is that ubiquitination of the MOs induces the formation of autophagosomes which also capture the mitochondria and cause their degradation.
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    Simultaneous utilization of glucose, xylose and arabinose in the presence of acetate by a consortium of Escherichia coli strains
    ( 2012-06-07) Xia, Tian ; Eiteman, Mark A ; Altman, Elliot
    Background: The efficient microbial utilization of lignocellulosic hydrolysates has remained challenging because this material is composed of multiple sugars and also contains growth inhibitors such as acetic acid (acetate). Using an engineered consortium of strains derived from Escherichia coli C and a synthetic medium containing acetate, glucose, xylose and arabinose, we report on both the microbial removal of acetate and the subsequent simultaneous utilization of the sugars.
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    Seed germination and seedling development ecology in world-wide populations of a circumboreal Tertiary relict
    ( 2012-03-04) Walck, Jeffrey L. ; Karlsson, Laila M. ; Milberg, Per ; Hidayati, Siti N. ; Kondo, Tetsuya
    Background and aims: Temperate forests are disjunct in the Northern Hemisphere, having become fragmented from the earlier widespread (Tertiary) boreotropical forest. We asked What are the contemporary patterns of population variation in ecological traits of a Tertiary relict in a macroecological context?. This issue underpins our understanding of variation in populations occurring in the same biome but on different continents.
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    Deep sequencing of the tobacco mitochondrial transcriptome reveals expressed ORFs and numerous editing sites outside coding regions
    ( 2014-01-13) Grimes, Benjamin T ; Sisay, Awa K ; Carroll, Hyrum D ; Cahoon, A Bruce
    Background: The purpose of this study was to sequence and assemble the tobacco mitochondrial transcriptome and obtain a genomic-level view of steady-state RNA abundance. Plant mitochondrial genomes have a small number of protein coding genes with large and variably sized intergenic spaces. In the tobacco mitogenome these intergenic spaces contain numerous open reading frames (ORFs) with no clear function.