Dalton Allen successfully defends his Master's thesis and begins PhD program. Dalton Allen (MS Biology 2020, PhD 2024) presented and defended his thesis titled "Metals in the Syr Darya and Shardara Reservoir, Kazakhstan:
An environmental and human health risk assessment." For his project, Dalton utilized data collected in 2015 by Dr. Jeffries and a team of international collaborators from University of Nebraska and Al-Farabi Kazakh National University to conduct ecological and human health risk assessments to determine the potential for metals present in the Shardara Reservoir to adversely impact the fishery and those consuming the fish. His results show that high levels of metals present in the surface waters of the Reservoir are likely to pose a risk to the health of the fishery; however, no risk to consumers of the fish were identified. Dalton's work contributes to a growing body of work aimed at better understanding the presence and impacts of contaminants in aquatic systems in Central Asian countries like Kazakhstan. (July 2021)
An environmental and human health risk assessment." For his project, Dalton utilized data collected in 2015 by Dr. Jeffries and a team of international collaborators from University of Nebraska and Al-Farabi Kazakh National University to conduct ecological and human health risk assessments to determine the potential for metals present in the Shardara Reservoir to adversely impact the fishery and those consuming the fish. His results show that high levels of metals present in the surface waters of the Reservoir are likely to pose a risk to the health of the fishery; however, no risk to consumers of the fish were identified. Dalton's work contributes to a growing body of work aimed at better understanding the presence and impacts of contaminants in aquatic systems in Central Asian countries like Kazakhstan. (July 2021)
Leah Thornton Hampton, a PhD student from the Jeffries lab, publishes an article related to her dissertation work. Leah (MS Biology 2015, PhD Biology 2020), Miranda Finch (BS Biology 2020) Dr. Chris Martyniuk (University of Florida), Dr. Barney Venables (University of North Texas) and Dr. Marlo Jeffries (Associate Professor of Biology) published an article in Scientific Reports titled "Developmental thyroid disruption causes long-term impacts on immune cell function and transcriptional responses to pathogen in a small fish model". The article describes work aimed at better understanding the long-term consequences of early-life-stage exposures to thyroid disrupting chemicals on immune function in fish. Leah's results show that developmental thyroid disruption leads to long-term alterations in key immune process at both the molecular and cellular levels. These findings show that normal thyroid hormone signaling is essential for immune system development in fish and also confirm that the immune system is an indirect target of thyroid disrupting chemicals. (July 2021)
Jeffries lab awarded AALAS grant to support research aimed at developing marine toxicity tests that are more protective of animal welfare. Dr. Marlo Jeffries (Associate Professor of Biology) and co-PI Dalton Allen (MS Biology 2021, PhD Biology 2024) were awarded a $10,164 grant from the American Association of Laboratory Animal Sciences to support portions of Dalton's dissertation work, as well as several undergraduate senior thesis projects, which aim to determine whether toxicological tests that feature marine fish embryos or invertebrates can replace those that feature marine fish larvae. This line of research is timely given recent legislative demands that call for improvements in the welfare of animals utilized in routine toxicity testing. Ultimately, this research will provide regulatory agencies with the data needed to adopt test protocols that are not only robust enough to ensure adequate protection of aquatic resources, but that also protect the welfare of organisms utilized in such protocols. (June 2021)
Austin Bryant successfully defends his Master's thesis. Austin (MS Biology 2020) successfully presented and defended his thesis to earn his MS degree. Austin's thesis research sought to determine whether early-life-stage thyroid disruption alters key behaviors in fathead minnows, an ecotoxicological model organism. The results of his work show that thyroid disruption induced by the model thyroid suppressant, propylthiouracil (PTU), lead to alterations in male reproductive behavior. This finding explains previous research carried out in the Jeffries lab which showed that developmental exposures to PTU lead to significant reductions in offspring production. Furthermore, it demonstrates the need to consider the long-term consequences of exposures to thyroid disrupting chemicals on reproduction and reproductive behavior. (May 2021)
Julie Krzykwa, a PhD student from the Jeffries lab, publishes an article stemming from her dissertation research. Julie Krzykwa (MS Biology 2017, PhD Biology 2020), Sarah King (BS Biology 2020), and Dr. Marlo Jeffries (Associate Professor of Biology) published an article in Environmental Science and Technology entitled “Investigating the predictive power of three potential sublethal endpoints for the fish embryo toxicity test: snout-vent length, eye size and pericardial edema." (Vol. 55, pg. 6907-6916; available here). The article presents a subset of the results of experiments conducted as part of Julie’s PhD dissertation project, which sought to enhance the fish embryo toxicity (FET) test by determining whether easily- observable morphological changes are predictive of adverse fitness outcomes. The results of this study revealed that alterations in embryo eye size were not predictive of adverse effects, but that reduced body length and the development of pericardial edema were predictive of mortality. These findings indicate that the addition of body length and pericardial edema as FET test endpoints would improve the sensitivity of the fathead minnow FET test making it a more robust tool for predicting the toxicity of chemicals and effluents. (April 2021)
Haley Schluterman presents her research to the JV Roach Honors College. Haley Schluterman (BS Neuroscience 2020) presented her Senior Honors research project during a virtual event hosted by the JV Roach Honors College. Haley's research focused on uncovering the impacts of trenbolone, an androgen used to promote cattle growth and found in surface waters, on immune function in female fish. Great work, Haley! (December 2020)
The Jeffries lab presents their research at Society of Environmental Toxicology and Chemistry (SETAC) North America SciCon2 Meeting. Dr. Marlo Jeffries (Associate Professor of Biology), Julie Krzykwa (MS Biology 2017, PhD Biology 2020), Austin Bryant (MS Biology 2021), and Haley Schluterman (BS Neuroscience 2020) each delivered presentations at the virtual SETAC North America SciCon2 Meeting. Dr. Jeffries delivered a presentation, which was co-authored by Lynsey Malin (MS Biology 2020) and Vuong Do (BS Biology 2020), showing that exposures to anti-estrogenic compounds lead to alterations in cellular immune function. Haley's presentation, co-authored by Andrew Mielcuszny (BS Biology 2021), focused on the impacts of trenbolone, an environmentally-relevant androgen, on female fathead minnow immune function. Austin delivered a presentation detailing a portion of his thesis work showing that early life stage thyroid disruption leads to long-term alterations in the reproductive behaviors of male fathead minnows. Julie presented a portion of her dissertation work which showed that decreased body length and increased pericardial area are strong predictors of delayed mortality in fathead minnow embryos and should thus be utilized as additional fish embryo toxicity test endpoints. (November 2020)
Julie Krzykwa, PhD student in the Jeffries lab, publishes two articles related to her dissertation research. Julie Krzykwa (MS Biology 2017, PhD Biology 2020) and Dr. Marlo Jeffries (Associate Professor of Biology) published one article in Chemosphere entitled “Comparison of behavioral assays for assessing toxicant-induced alterations in neurological function in larval fathead minnows" (Vol. 257, pg. 126825; available here) and a second article in MethodsX titled "Development of a larval fathead minnow optomotor response assay for assessing visual function" (Vol 7, pg. 100971, available here). The articles present a subset of the results of experiments conducted as part of Julie’s PhD dissertation project, which sought to enhance the fish embryo toxicity (FET) test by determining whether easily observable alterations in eye size were indicative of adverse neurological effects. These papers describe efforts to refine and improve existing methods for evaluating ecologically-relevant behaviors, including those related to feeding, schooling, and predator avoidance, in larval fathead minnows. They also demonstrate the relative sensitivity of these assays for the detection of adverse neurological impacts. Overall, the results of these studies strengthen the existing framework for evaluating the neurological and behavioral impacts resulting from exposures to chemical contaminants. (October 2020)
Leah Thornton Hampton, PhD student in the Jeffries lab, publishes an article describing the transcriptomic responses of fathead minnows following bacterial infection. Leah (MS Biology 2015, PhD Biology 2020), Dr. Chris Martyniuk (University of Florida), Dr. Barney Venables (University of North Texas) and Dr. Marlo Jeffries (Associate Professor of Biology) published an article in Fish and Shellfish Immunology entitled “Advancing the fathead minnow (Pimephales promelas) as a model for immunotoxicity testing: Characterization of the renal transcriptome following Yersinia ruckeri infection" (Vol. 103, pg. 472-480; available here). This article details a portion of Leah's dissertation work which sought to further develop the fathead minnow as a model for immunotoxicity testing by identifying genes associated with key immune responses. Leah found that more than 1800 genes, many of which are associated with innate immunity, complement, hemorrhaging and iron absorption, were altered following infection. Future studies will be able to utilize the molecular targets identified in Leah's study to better understand the impacts of contaminants on pathogen-induced immune responses in fathead minnows, an emerging immunotoxicity model. (August 2020)
Leah Thornton Hampton, PhD student in the Jeffries lab, publishes an article detailing methods for evaluating cellular immune function in fathead minnows. Leah (MS Biology 2015, PhD Biology 2020), Dr. Marlo Jeffries (Associate Professor of Biology) and Dr. Barney Venables (University of North Texas) published an article in MethodsX titled “A practical guide for assessing respiratory burst and phagocytic cell activity in the fathead minnow, an emerging model for immunotoxicity" (Vol. 7, pg. 100992; available here). This article presents the results of Leah's efforts to refine cellular immune assays and provides detailed protocols for isolating immune cells, measuring phagocytic cell activity and assessing respiratory burst activity in the fathead minnow. (July 2020)
Dr. Jeffries and Leah Thornton Hamptom co-author a publication describing pesticide occurrence and ecological risk in the Syr Darya, a freshwater source that feeds the Aral Sea. Leah (MS Biology 2015, PhD Biology 2020) and Dr. Jeffries (Associate Professor of Biology), along with an international team of researchers from the University of Nebraska (Drs. Dan Snow and Shannon Bartelt-Hunt), University of Idaho (Dr. Alan Kolok), University of York (Dr. Brett Sallach), SRM Institute of Science and Technology – Tamil Nadu (Dr. Paromita Chakraborty), and Al-Frarabi Kazakh National University (Drs. Bolat Uralbekov and Bagdat Satybaldiev), published an article titled "Legacy and current pesticide residues in Syr Darya, Kazakhstan: Contamination status, seasonal variation and preliminary risk assessment" in Water Research (2020, Vol. 184:116141; available here). This article details a portion of an NSF-funded project, in which the presence of agrichemicals was evaluated in water and sediments collected from the Syr Darya, a river that feeds the ecologically-imperiled Aral Sea. Study results revealed that both modern-day and banned legacy pesticides are present in the river and that these contaminants pose a significant risk to the health of aquatic organisms. The information gained through this study identifies environmental factors that warrant consideration given ongoing efforts aimed at restoring the Syr Darya and the Aral Sea. (July 2020)
Haley Schluterman, Andrew Mielcuszny, and Austin Bryant receive grants to support their research. Haley (BS Neuroscience 2020) received $1500 from the JV Roach Honors College to support her senior thesis research which aims to uncover the impacts of trenbolone, an androgenic chemical associated with cattle production and detected in surface waters downstream of cattle feedlots, on immune function in fathead minnows. Andrew (BS Biology 2021) was awarded $1000 in College of Science and Engineering (CSE) SERC funds to support his work which seeks to examine sex-based differences in cellular immune function. Austin (MS Biology 2021) was awarded $1000 to support his thesis research which seeks to better understand the impacts of early-life-stage thyroid disruption on neurodevelopment and behavior. Congrats to Haley, Andrew, and Austin! (June 2020)