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ItemMetagenomic Profiling of Nitrogen Cycling Potential in Caribbean Sponges(Middle Tennessee State University, 2024)The high species diversity of coral reefs is in part possible because of the efficient recycling of essential nutrients facilitated by resident organisms and their microbiomes. Sponges and their symbionts play a role in the recycling of nutrients and help ensure productive energy flow, allowing coral reefs to thrive. Here we present a metagenomic analysis of common and abundant sponges from the Caribbean, where microbial metagenome assembled genomes (MAGs) were assembled from shotgun sequencing data and were annotated for metabolic function. We focused on the completeness of nitrogen cycling pathways and the presence of genes from these pathways because bioavailability of nitrogen compounds can be essential in maintaining high biodiversity on coral reefs. We recovered high-quality genomes that spanned twenty-five unique taxa, with eleven of them contributing to the nitrogen cycling potential of the sponge holobiont. Insights on how common reef animals such as sponges interact with biologically important compounds may be a key component in understanding how coral reefs will continue to change in the coming decades.
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ItemNashville's First Public Historian: Jessie Carney Smith At Fisk University(Middle Tennessee State University, 2024)In 1965, Smith began her career as head librarian at Fisk, making endless contributions to black history. By the time of her retirement, several contemporaries concluded that her encyclopedias promoted black women’s history and helped public education. Though there has been increasing interest in black librarianship, Smith somehow slips through the cracks. While Arturo Schomburg, and Dorothy Porter were exceptional at both Fisk and Howard libraries, Smith furthered their pursuit of black history. Not guilty of self-adulation, Smith rarely mentions her accomplishments. Instead, she insists that Fisk should commemorate her great mentor and predecessor Arna Bontemps. After all, it was those early years with Bontemps that introduced her to librarianship, and that formed the ethos of her first decade as head librarian.
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ItemInvasion of Phagocytic and Non-Phagocytic Cells by ‘Candidatus Berkiella cookevillensis’(Middle Tennessee State University, 2024)Bacterium ‘Candidatus Berkiella cookevillensis’ (strain CC99) was isolated from an amoeba in cooling tower biofilm. CC99 is an obligate intracellular pathogen growing within vacuoles closely associated with the host cell nucleus and typically lysing its amoeba host in 3-4 days. CC99 that lyse from amoebae can infect both THP-1 and U937 human macrophage-like cell lines, but whether bacteria from human cell lines are transmissible to other human cells had not been investigated. In this study, CC99 bacteria lysed from amoebae productively infected both THP-1 and HeLa human epithelial cells, as evidenced by nuclear-associated vacuoles filled with bacteria. At least 50% of the cell populations were positive for CC99 at 72 hours as determined by histochemical staining. Furthermore, CC99 DNA was detected in these treated cells using quantitative PCR (qPCR). However, when CC99 was grown in either THP-1 or HeLa cells, no bacteria were detectable in these cells either by histochemical staining or by qPCR at 72 hours. These results suggest that although bacterium CC99 may be transmissible to human cells when lysed from amoebae, CC99 propagated in human cells may not be directly transmissible to other human cells. Therefore, this study has important implications for the safety procedures surrounding amoeba-derived infections, such as Legionella spp.
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ItemOffice Housework, Organizational Citizenship Behaviors, and Work Ethic: A Correlational Study(Middle Tennessee State University, 2024)This research focused on the relationship between individual work ethic and how that impacts employee contextual job performance, including both organizational citizenship behaviors and office housework. The office housework literature has grown over the past few years, but there is much research still needed to understand this contextual job behavior. Correlations between work ethic, organizational citizenship behaviors, and office housework were tested. A relationship was found between office housework and organizational citizenship behaviors aimed at the individual (OCB-Is), but not organizational citizenship behaviors focused on the organization (OCB-Os). Additionally, work ethic did not significantly relate to organizational citizenship behaviors focused on the organization (OCB-Os). Office housework and OCB-Is were both related to four work ethic dimensions: centrality of work, hard work, wasted time, and delay of gratification. Findings of this study help demonstrate the similarities and differences in the relationship between office housework and organizational citizenship behaviors, using work ethic. Further studies should attempt to help define the different types of contextual job performance behaviors, and what drives employees to complete them.
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ItemDevelopment of a Novel Shuttle Vector for Tetragenococcus halophilus(Middle Tennessee State University, 2024)Tetragenococcus halophilus is used by companies in a variety of fermented foods while also being shown to be capable of being a potent probiotic. T. halophilus fermentative batches are at risk of being compromised by viral pathogens, which leads to product loss in the industry. To address the need for a molecular toolset that was capable of being maintained in T. halophilus that expresses desired genes, a plasmid (pCBW2) was designed and built in E. coli. With T. halophilus having no prior optimized way of transformation, multiple methods of transformation were tested in an attempt to introduce pCBW2 to T. halophilus. The plasmid pCBW2 was built using PCR and restriction enzymes to insert a combination of preexisting reporter elements paired with hypothetical promoters from T. halophilus genomic DNA. After construction, chemical transformation, electroporation, and biolistic transformation methods were attempted under a variety of conditions to introduce the constructed plasmid to T. halophilus. While no attempts of the transformation of T. halophilus were successful, conventional chemical transformation of E. coli was successful. E. coli were able to utilize promoters endogenous to T. halophilus, suggesting pCBW2 is a functional plasmid capable of expressing provided genes of interest.