Mercury (Hg) is a hazardous contaminant that can be transferred from aquatic to terrestrial environments by emerging aquatic insects. Terrestrial predators, such as spiders, that live along shorelines of water bodies may consume emerging aquatic insects and become contaminated with Hg. Mercury-contaminated spiders may pose a risk to arachnivorous songbirds. The degree to which most families of spiders are contaminated with Hg and the risk they pose to songbirds is not well understood. The objectives of this study were to determine 1) Hg concentrations in seven families of shoreline spiders, 2) if each family was connected to the aquatic food web via the consumption of emergent insects and 3) determine the risk these spiders pose to arachnivorous birds. We collected representatives from seven families of spiders along with a variety of aquatic and terrestrial plant, invertebrate, and fish samples from 10 ponds located in north Texas, USA. We used methylmercury (MeHg) concentrations in combination with stable isotopes of nitrogen (δ15N) to determine if each family of shoreline spider was connected to the aquatic food web. All spider taxa in the present study were contaminated with Hg and connected to the aquatic food chain. We calculated wildlife values for various songbirds to determine health risks that Hg-contaminated spiders may pose to songbirds. Spider based wildlife values revealed that six of the seven families of shoreline spiders examined had concentrations of MeHg high enough that they may pose a risk to arachnivorous songbirds that forage for spiders along shorelines of ponds.

Cancer is the second-leading cause of death in the US. Cancer cells are characterized by loss of regulation of the cell cycle that results in uncontrolled proliferation. To drive this high rate of cellular division, cancer cells have mutated to increase uptake of important nutrients including glucose and vitamins by increasing the number of glucose receptors and vitamin transporters, including biotin receptor, on their surface. Due to this difference in expression of biotin receptor between cancer and normal cells, research focusing on the use of biotin-conjugated molecules has gained attention as a method for anticancer drug delivery.
Another characteristic unique to certain cancer cells is that they exhibit dysregulation in normal cellular redox balance, such that the cellular environment becomes more reducing. A more reducing environment favors the generation of reactive oxygen species (ROS). Many metal-based anticancer drugs have taken advantage of this feature of cancer cells in an attempt to increase the levels of ROS to the point that harmful oxidation reactions occur that lead to cell death. Specifically, the iron atom of ferrocene has been shown to lead to the generation of damaging ROS upon oxidation from Fe2+ to Fe3+.
A problem with current cancer treatment is that the chemotherapeutics often are not specific to cancer cells and can lead to negative side effects. As a result, anticancer drugs with high specificity and cytotoxicity are needed to improve treatments. This research project focuses on testing the cytotoxicity of a variety of biotin-ferrocene derivatives on cancer (HeLa) and non-cancer (293HEK) cell lines. HeLa cells are known to express high levels of biotin receptor and are predicted to have more reducing cellular environments; additionally, 293HEK cells express low levels of biotin receptor and are predicted to have less reducing environments. The tested compounds have three main features: a biotin moiety, a ferrocene core, and a variable linker covalently bound to the ferrocene moiety. We hypothesize that the biotin-containing compounds will enter HeLa cells more efficiently than 293HEK cells, allowing for the ferrocene moiety to reduce oxygen, leading to increased ROS generation and cell death.
Here, we demonstrate that ferrocene shows dose-dependent cytotoxicity specific to HeLa cells, while one of the compounds shows dose-dependent cytotoxicity specific to 293HEK cells. Interestingly, two of the compounds show dose-dependent cytotoxicity to both cell lines. These findings are particularly intriguing in that there appears to be a difference in specificity between some of the compounds. However, future studies are required to reveal how these differences in cytotoxicity are related to the differences in chemical moieties and by what mechanisms these compounds are acting to cause specific cytotoxicity.

Most plants acquire mineral nutrients from the soil. However, in nutrient-poor environments, some plants have evolved carnivorous traits that allow them to obtain nutrients by capturing and digesting insects. For example, the carnivorous pitcher plant Sarracenia alata uses passive pitfall traps to capture their insect prey. Although studies have examined prey composition for S. alata, few have included a comparison to the insects available in the environment. The purpose of this study was to compare prey capture of S. alata pitchers with the available insects to determine whether this species is selective in prey capture. The available insects were sampled using artificial sticky traps in the vicinity of the pitchers. The insects in the study were identified first to the level of order and then further identified to “morphospecies” as a means of examining preference on a finer scale. The results show that the pitchers captured only a subset of the available insects. The average number of orders captured by each pitcher (1.8 ± 1.0 SD) was lower than that captured by artificial traps (2.8 ± 0.5). Likewise, the average number of morphospecies captured by the pitchers (4.5 ± 4.8) was lower than that captured by the artificial traps (6.8 ± 3.5). These results support the hypothesis that S. alata is selective in its prey capture, but further studies are needed with different methods of measuring the available insects in order to avoid potential bias.

Globally, there is demand for increased meat production. Texas, a leader in cattle production in the United States, has met this demand utilizing confined animal feeding operations (CAFOs) containing hundreds to thousands of cattle. To increase production efficiency, cattle receive growth-promoting hormone treatments to enhance growth and increase cattle mass. These hormonally-active compounds (HACs) have been found in cattle waste, feedlot runoff, and surface waters. The ultimate goal of this project was to identify watershed characteristics that promote the transport of cattle-associated HACs to surface waters. Therefore, the objectives of this pilot study were to: 1) identify and define a study area for evaluating HACs in Texas watersheds and 2) begin preliminary assessments of HAC activity in watersheds downstream of cattle feedlots. A suitable study site was identified using satellite imagery, elevation data and the ArcGIS hydrology tool pack. Sample sites were selected within this area based on geographical features and position to CAFOs. Caged fish studies, followed by analysis of estrogen-responsive gene expression, were utilized to assess the presence and activity of HACs. Though no statistically significant alterations in estrogen-responsive gene expression metrics were observed, females from three of the four sites downstream of CAFOs experienced 2.9 to 3.7-fold and 1.9 to 5.3-fold decreases in the expression of estrogen receptor alpha and vitellogenin, respectively. This could have larger implications as previous research by Miller et al. 2007 forecasted that a 50% reduction in vitellogenin plasma concentration could result in a 41.8% decrease in average population size after one year.

Rainbow trout, Oncorhynchus mykiss, exhibit two life-history strategies: resident rainbow trout and migratory steelhead trout. Previous research has shown that the migratory decision is highly heritable. Recently, interest has focused on the GREB1L gene as studies in several populations of rainbow trout have found alleles associated with migration. This project aimed to measure allelic associations between GREB1L and migratory life-history in rainbow trout from Sashin Creek, Alaska. Sequence data suggests that all individuals, regardless of migratory trajectory, had alleles associated with migration. These results confirm that there are population specific genetic effects that determine the migratory life-history of rainbow trout.