Delaney Jennifer

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Delaney
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Jennifer
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  • Article
    Physiological dynamics of chemosynthetic symbionts in hydrothermal vent snails
    (Springer Nature, 2020-07-02) Breusing, Corinna ; Mitchell, Jessica ; Delaney, Jennifer ; Sylva, Sean P. ; Seewald, Jeffrey S. ; Girguis, Peter R. ; Beinart, Roxanne A.
    Symbioses between invertebrate animals and chemosynthetic bacteria form the basis of hydrothermal vent ecosystems worldwide. In the Lau Basin, deep-sea vent snails of the genus Alviniconcha associate with either Gammaproteobacteria (A. kojimai, A. strummeri) or Campylobacteria (A. boucheti) that use sulfide and/or hydrogen as energy sources. While the A. boucheti host–symbiont combination (holobiont) dominates at vents with higher concentrations of sulfide and hydrogen, the A. kojimai and A. strummeri holobionts are more abundant at sites with lower concentrations of these reductants. We posit that adaptive differences in symbiont physiology and gene regulation might influence the observed niche partitioning between host taxa. To test this hypothesis, we used high-pressure respirometers to measure symbiont metabolic rates and examine changes in gene expression among holobionts exposed to in situ concentrations of hydrogen (H2: ~25 µM) or hydrogen sulfide (H2S: ~120 µM). The campylobacterial symbiont exhibited the lowest rate of H2S oxidation but the highest rate of H2 oxidation, with fewer transcriptional changes and less carbon fixation relative to the gammaproteobacterial symbionts under each experimental condition. These data reveal potential physiological adaptations among symbiont types, which may account for the observed net differences in metabolic activity and contribute to the observed niche segregation among holobionts.
  • Preprint
    Toward establishing model organisms for marine protists : Successful transfection protocols for Parabodo caudatus (Kinetoplastida: Excavata)
    ( 2017-06) Gomaa, Fatma ; Garcia, Paulo A. ; Delaney, Jennifer ; Girguis, Peter R. ; Buie, Cullen R. ; Edgcomb, Virginia P.
    We developed protocols for, and demonstrated successful transfection of, the free-living kinetoplastid flagellate Parabodo caudatus with three plasmids carrying a fluorescence reporter gene (pEF-GFP with the EF1 alpha promoter, pUB-GFP with Ubiquitin C promoter, and pEYFP37 Mitotrap with CMV promoter). We evaluated three electroporation approaches: 1) a square-wave electroporator designed for eukaryotes, 2) a novel microfluidic transfection system employing hydrodynamically-controlled electric field waveforms, and 3) a traditional exponential decay electroporator. We found the microfluidic device provides a simple and efficient platform to quickly test a wide range of electric field parameters to find the optimal set of conditions for electroporation of target species. It also allows for processing large sample volumes (> 10 ml) within minutes, increasing throughput 100 times over cuvettes. Fluorescence signal from the reporter gene was detected a few hours after transfection and persisted for 3 days in cells transformed by pEF-GFP and pUB-GFP plasmids and for at least 5 days post-transfection for cells transformed with pEYFP-Mitotrap. Expression of the reporter genes (GFP and YFP) was also confirmed using reverse transcription-PCR (RT-PCR). This work opens the door for further efforts with this taxon and close relatives toward establishing model systems for genome editing.