Anderson, Kelsi L., PhD.

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    The staphylococcal accessory regulator, SarA, is an RNA-binding protein that modulates the mRNA turnover properties of late-exponential and stationary phase Staphylococcus aureus cells
    (Frontiers in Cellular and Infection Microbiology, 2012-03) Anderson, Kelsi L., PhD Morrison, John M. Beenken, Karen E. Smeltzer, Mark S. Dunman, Paul M.
    The modulation of mRNA turnover is gaining recognition as a mechanism by which Staphylococcus aureus regulates gene expression, but the factors that orchestrate alterations in transcript degradation are poorly understood. In that regard, we previously found that 138 mRNA species, including transcripts coding for the virulence factors protein A (spa) and collagen-binding protein (cna), are stabilized in a sarA-dependent manner during exponential phase growth, suggesting that SarA directly or indirectly affects the RNA turnover properties of these transcripts. Herein, we expanded our characterization of the effects of sarA on mRNA turnover during late-exponential and stationary phases of growth. Results revealed that the locus affects the RNA degradation properties of cells during both growth phases. Further, using gel mobility shift assays and RIP-Chip, it was found that SarA protein is capable of binding mRNA species that it stabilizes both in vitro and within bacterial cells. Taken together, these results suggest that SarA post-transcriptionally regulates S. aureus gene expression in a manner that involves binding to and consequently altering the mRNA turnover properties of target transcripts.
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    Active learning in the undergraduate classroom: A journal-club experience designed to accentuate course content
    (National Association of Biology Teachers, 2016) Anderson, Kelsi L.
    Students in the natural sciences should be prepared as undergraduates to read and apply concepts from the scientific literature. I describe a strategy that enforced the necessity to deliver high volumes of content while incorporating an active-learning technique. Students were assigned to read and discuss articles from the scientific literature that complemented content being delivered via traditional lecture. Students were encouraged to participate by coming to class prepared with written questions, and discussion was directed by instructor-prepared prompts. Students were assessed via low-stakes assignments based primarily on participation. This teaching method has proved effective, as verbally reported by past students who are currently enrolled in graduate programs. These students report feeling more prepared than their peers to discuss and learn from the scientific literature.
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    Characterizing the Antibacterial Properties and Transcriptional Alternations Induced by Lemongrass Oil in Staphylococcus aureus
    (The Journal of Experimental Microbiology & Immunology+, 2017) Christensen, Collin J.; Anderson, Kelsi L
    Essential oils have risen in popularity as “all natural” alternatives used to treat a myriad of conditions. To begin to elucidate the antibacterial properties of essential oils, we tested the effectiveness of lemongrass oil (LGO), tea tree oil (TTO), and willow bark extract (WBE) against Staphylococcus aureus growth. To do so, a Methicillin-Resistant strain of Staphylococcus aureus (USA300) was exposed to each oil using disk diffusion assays. Of the oils, LGO had the greatest zone of inhibition. The Minimum Inhibitory Concentration (MIC) of both LGO and citral (the primary chemical component of LGO) was determined in macro-broth cultures; exposure to increased concentrations of each resulted in dramatic cell death as determined by cell growth assays. To begin to determine the molecular mechanisms underlying the observed antibacterial effects, we exposed cells to a sub-inhibitory concentration of citral and hybridized the RNA to Affymetrix GeneChips®. Transcripts differentially affected in citral- versus mocktreated cells represent virulence factors, hypothetical proteins, and intergenic regions. Taken together, these results demonstrate that LGO exhibits antibacterial properties against a highly pathogenic bacterial species that is exceedingly resistant to the currently available antibiotics.