Bacillus anthracis is the bacterial pathogen responsible for the lethal disease anthrax. For the pathogens to cause disease, they must overcome several host defenses including obtaining essential nutrients like iron. Our lab has identified that the dUTPase-1 gene is critical for iron acquisition from hemoglobin in B. anthracis. Normally, dUTPase functions to hydrolyze dUTP into dUMP. This functions to maintain DNA integrity as hydrolysis lowers the concentration of dUTP preventing uracil incorporation. This enzyme has never been linked to iron acquisition before, although in other systems, it has been linked with a secondary role in regulating signaling. Our goal is to determine whether the enzymatic activity, dUTP hydrolysis, is important for iron acquisition from hemoglobin. We hypothesize that dUTPase’s enzymatic activity is not responsible for the iron acquisition phenotype, and that it is through another mechanism. To test this we will introduce amino acid substitutions into two highly conserved residues in the active site using site-directed mutagenesis. This mutation should destroy enzymatic activity which we will confirm using a PCR-based assay. We will then test for iron acquisition ability using our established hemoglobin assay. We are currently working on the construction of our enzymatic mutant and optimizing our hemoglobin to test it once it is completed. This research will help us determine which structural domains are key to the iron acquisition activity of dUTPase and shed light on the secondary function of this enzyme.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that affects behavior, memory, and overall health and well-being. Although it is the sixth leading cause of death in the United States among people aged 65 and older, there is currently no cure or effective preventive treatment. Multiple risk factors contribute to the development of AD, including aging, genetics, chronic stress, and diet. Increasing evidence suggests that diet is a major modifiable factor influencing disease risk through mechanisms involving systemic inflammation and oxidative stress. Diets high in saturated fats, refined carbs, and sugars typical of the American diet promote lipid buildup, especially in the liver. Excess hepatic lipids can cause fatty liver, metabolic issues, inflammation, and oxidative damage, potentially contributing to AD pathology. To better understand how diet influences these biological pathways, our lab developed two macronutrient and calorie-matched rodent diets: one that models a Mediterranean-style diet (MD) and another representing the typical American diet (TAD). Previous studies in our lab using male and female C57BL/6J wild-type mice examined the effects of these diets over shorter periods. In a three-month dietary exposure study, mice fed the TAD exhibited notably greater hepatic lipid accumulation compared to those fed MD, suggesting early metabolic stress. However, gene expression analyses did not show significant evidence of inflammation or oxidative stress. This suggests the duration might not have been sufficient to detect molecular changes. This study prolonged diet exposure to six months to determine whether extended TAD intake leads to alterations in liver gene expression associated with inflammation and oxidative stress. We examined several inflammatory genes (e.g., TNF-α, Il-1β, and IL-6) and oxidative stress-related genes (e.g.,NRF2, HO-1, and SOD) and found that mice on the TAD showed higher expression of inflammatory and oxidative stress markers than MD-fed mice. Our lab has also previously demonstrated that six-month consumption of the TAD diet leads to AD-related markers such as elevated amyloid-β levels in the brain and the associated decrease in cognitive function. Combined, these results suggest that prolonged exposure to poor dietary conditions encourages inflammatory and oxidative stress signals from the liver, which may help drive AD pathology.

The Texas Horned Lizard (Phrynosoma cornutum) has undergone dramatic population declines across its native range due to habitat loss, invasive species, and predation. As a result, Texas zoos and the Texas Parks and Wildlife Department have been attempting to reintroduce hatchlings of this species into areas where it has become extinct. To support reintroduction, graduate researchers from TCU’s biology program glued harmonic tags onto the backs of the hatchling THL, making them easier to locate in the wild and to determine the most viable areas for reintroduction. The hatchlings, however, still experience high predation, and we often find their tags in the scat of various predators, such as snakes, birds, and small mammals. Previous tracking studies suggest coachwhip snakes (Masticophis flagellum) are a major predator of these lizards. Identifying the primary predators of reintroduced populations is critical for improving hatchling survival and informing conservation strategies. Tissue samples were collected for coachwhips, other potential Texas snake predators, and a few mammals to create and test a coachwhip-specific primer. We extracted DNA from the scat and used the coachwhip-specific genetic marker and a horned lizard-specific primer to screen over 80+ fecal samples with tracking tags collected across multiple THL release sites from the 2024 fall season. The results of this study will be used to determine how common coachwhip predation is at the reintroduction sites and whether management actions can be implemented to reduce predation during the early hatchling stage.

Reproductive success in oviparous reptiles is shaped by both nest environment and post-emergence resource availability. While the abiotic conditions of a reptile’s nest can greatly influence hatching success, post-emergence resource availability affects hatchling survival and growth. Many studies evaluate whether females favor particular nesting sites based on abiotic conditions; however no studies have linked nest site choice with post-emergence resource availability. Understanding this relationship could improve habitat management and enhance survival in Texas horned lizard (Phrynosoma cornutum) reintroduction programs. The species’ strong dietary specialization, particularly the reliance of hatchlings on small native ants (Crematogaster, Dorymyrmex, Pheidole, and Tetramorium spp.), makes it possible to test whether females select nest sites that maximize post-emergence prey availability. During the summers of 2023 and 2024, we located 21 nests of Texas horned lizards at a reintroduction site at Mason Mountain WMA and at a natural population (~42 km away) in central Texas. We compared nest and random sites to assess a female’s ability to select a nest site based on fire ant abundance, native ant abundance, soil moisture, soil compaction, and vegetation structure. Using stepwise model selection, results suggest that horned lizards select nest sites that have low soil compaction, reduced grass cover, and high amounts of hatchling prey. This information will be used to determine if there are suitable nesting areas at reintroduction sites and how to best manage land for optimum horned lizard survival. Release sites with softer soil, less grass, and higher abundance of native ants should be prioritized.

A notable occupational gap exists within the STEM (Science, Technology, Engineering, and Mathematics) field between employed women and men. It is likely to occur around the ages of 10-12, as this is when girls typically start to lose interest in STEM-related activities. The purpose of this study is to investigate the views of fourth- and fifth-grade girls on STEM, careers, and post-secondary education as they participate in the STEMpower After-School Club. Additionally, we aim to determine the students’ baseline STEM identities and their interests in STEM careers following their participation in the STEMpower After-School Club. This study is being conducted by following a group of fourth and fifth-grade girls during a year-long academic after-school program. Our methods include a STEM careers survey.