Graduate Student Research Conference
Permanent URI for this collectionhttps://hdl.handle.net/10877/8272
The Graduate College invites graduate students from all disciplines to present at the Graduate Student Research Conference (GSRC) (previously known as the International Research Conference) and showcase their original research and creative works!
Graduate Student Research Conference Website: https://www.gradcollege.txst.edu/events/research/graduate-student-research-conference.html
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Browsing Graduate Student Research Conference by Department "Biology"
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Item Bacteria fight club: Identifying probiotics for goldfish(2021-04) Ortiz, Whitney; Huertas, Mar; Carlos-Shanley, CamilaExposure to pollutants, like nitrite, negatively impacts fish both directly and indirectly. Nitrite can cause brown blood disease in fish when they are exposed to elevated nitrite concentrations. This occurs when hemoglobin is converted into methemoglobin which cannot transport oxygen. Although the direct effects of nitrite are well studied, it is unknown how nitrite impacts the microbiome. The microbiome is important because it supports the immune system by taking resources from pathogens and competing directly with them using antimicrobial molecules. When the microbiome is disrupted, it can lead to increased susceptibility to disease and disturbed physiological functions, which can lead to death. Probiotics, a microorganism administered for its beneficial attributes, are often used to stabilize a disrupted microbiome. The added bacteria are specifically selected to correct an imbalance by recolonizing the microbiome, releasing useful metabolites, and competing with pathogens. The impact of elevated nitrite concentrations on fish is important because they are a major food source. However, when they are farmed in aquaculture, they are exposed to elevated levels of nitrite. This study aimed to identify probiotic candidates that could be used to stabilize the fish microbiomes after they were exposed to elevated concentrations of nitrite. To accomplish this, bacteria were isolated from the tissues of healthy goldfish by swabbing with sterile swabs, growing on ½ BHI or R2A media, and identified using Sanger sequencing. A competition and agar plug assay were then used to determine the antimicrobial properties of the candidates against Yersinia ruckeri, Edwardsiella ictaluri, Vibrio harveyi, and Aeromonas hydrophilia which are common fish pathogens in aquaculture. The pathogens were plated with the probiotic candidates to see which candidate inhibited the growth of the pathogens. Of the 22 candidates tested, 15 were able to inhibit the growth of at least one pathogen on an agar plug or competition assay. The candidates were then exposed to the same tests with nitrite in the media to identify those that could inhibit pathogen growth when grown with nitrite. The two best candidates were a Pseudomonas and Pseudoxanothomonas species. These bacteria were isolated from healthy goldfish and should be safe while also inhibiting pathogen growth. Probiotics have the potential to mitigate the negative effects of nitrite exposure in fish, and bacteria isolated from healthy fish should not pose a risk. These probiotics could be used in aquaculture to reduce the cost and increase fish production. While probiotics have been used to stabilize the microbiome, there has been no research into how probiotics could be used to stabilize the microbiome from nitrite exposure. Additionally, this probiotic would be used while the fish are still being exposed to elevated nitrite levels and would have to both thrive and prevent pathogen growth at these higher levels. This research, therefore, is investigating the potential benefits of unexplored probiotics that have the potential to drastically help aquaculture production.Item Distribution of the Mediterranean gecko (Hemidactylus turcicus) in Texas(2021-04) Bassett, Lawrence G.; Zughaiyir, Ferris E.; Forstner, Michael R. J.The Mediterranean Gecko (Hemidactylus turcicus) is a small (10 – 12.7 cm total length) nocturnal gekkonid lizard native to southern Europe, northern Africa, and far-west Asia. It has been introduced to many areas outside its native range and has established numerous populations throughout the United States. The first report of H. turcicus from Texas was from Cameron County in 1955. Since then, H. turcicus has become established throughout much of the state and new county occurrence records continue to be published regularly. Despite the efforts of numerous herpetologists, the distribution of H. turcicus within Texas remains poorly known. The last county-delineated state-wide distribution map was published in 2013 and was promptly made obsolete with the publication of 16 Texas county records in 2014. In total, 55 Texas county records have been published for H. turcicus since the last state-wide distribution map was printed. We provide an updated state-wide distribution map and report on our efforts to elucidate the distribution of H. turcicus in Texas. From 2019 – 2021, we travelled to 23 Texas counties to search for H. turcicus. Nocturnal surveys were conducted in each county around anthropogenic structures in urban habitats. Mediterranean geckos were found in 21 counties and voucher specimens were deposited at the Amphibian and Reptile Diversity Research Center at the University of Texas at Arlington. Our findings demonstrate substantial range expansion of H. turcicus in Texas. Further surveys should be conducted throughout the state as conspicuous gaps in our distribution map exist. Special attention should be given to H. turcicus populations occupying semi-natural habitats in west Texas and determining interactions between this non-native lizard and the native herpetofauna.Item Rapid Nucleic Acid Concentration from Wastewater with Minimal Equipment: New Strategy for COVID-19 Surveillance(2022-04) Long, ShannonBackground: As of 26 March 2022, COVID-19 has killed over six million people worldwide, with almost one million of those deaths being in the United States (World Health Organization, 2022). Wastewater-based epidemiology is an effective tool for monitoring COVID-19 on a community level and catching and suppressing emerging outbreaks (Betancourt et al., 2021). However, this requires SARS-CoV-2 RNA to be concentrated from wastewater for PCR testing. A rapid, inexpensive, and uncomplicated method of RNA concentration would facilitate widespread deployment of wastewater-based epidemiology for COVID-19, especially in low-resource settings. Hollow silica microspheres float in water and can be functionalized to bind target molecules on cells of interest (Weigum et al., 2016), so they could potentially be adapted to bind to RNA and carry it to the top of a sample. Purpose: To demonstrate the capacity of hollow silica microspheres to isolate RNA from aqueous solution. Methodology: Hollow silica microspheres were functionalized with chitosan, a nucleotide-binding molecule (Yang et al., 2017). The functionalized microspheres were then mixed with a fluorescent oligonucleotide for varying amounts of time, after which micrographs were taken. Fluorescence around the microspheres was quantified with ImageJ. Research: Preliminary findings suggest that the functionalized microspheres can capture oligonucleotides in as little as ten minutes. Follow-up experiments are exploring nucleotide capture at sub-10-minute intervals. Conclusion: Chitosan-functionalized hollow silica microspheres have potential as a tool for rapid RNA concentration from wastewater. Future experiments will focus on liberating nucleic acids from the microspheres for detection after capture, in addition to further optimization of the nucleic acid capture process, including reducing the time needed for capture.