Mutations in myosin may lead to severe muscle disorders that greatly reduce the quality of life. For example, the embryonic skeletal myosin (MYH3) mutation R672C leads to Freeman Sheldon Syndrome (FSS), a rare inherited disorder that causes severe contractures at birth. A comprehensive understanding of the relationship between protein structure and function is urgently needed to treat diseases such as FSS. Computational methods, such as molecular dynamics simulations, can be used to examine the effects of mutations on protein structure and function. However, the Protein Data Bank (PDB) is missing most human skeletal myosin heavy chain structures. We employed homology modelling to construct structures of human MYH3. To inform homology modeling, I generated a multiple sequence alignment of 7 human myosin genes. The extent of sequence identity was used to identify the optimum myosin isoforms to use as templates for model generation. For example, MYH3 and MYH7 were the most distinct at 78.93% similarity, which was expected as they are embryonic skeletal and adult cardiac myosin respectively. Specific sequence consensus at each position in the sequence was used to determine the most and least conserved regions of myosin. The cleft region was the most conserved; the N-terminal Domain was the least conserved. I used MYH7, adult cardiac myosin, as a template structure to derive a homology model of the ATP state of MYH3. A structure of MYH3 R672C was generated via in silico mutation of the wild type structure. Molecular dynamics of the resulting structures will be used to explore how R672C, which is located near myosin’s converter domain, alters myosin structure and function. This computational platform will model all phases of the cross-bridge cycle, potentially reveal new drug binding pockets, guide and be validated by in vitro experiments using human induced pluripotent stem cell derived myocytes (hiPSC-Ms).

From the Dakota Access Pipeline demonstrations to increasing popularity around climate-activist-turned-household-names like Greta Thunberg, a resurgence of environmental advocacy has taken the 21st century by storm. The environmental justice movement, a term first coined in the 1980s, was born from the idea that mainstream environmentalism does not examine environmental policy in the intersection of socioeconomic status and race. This literature review explores the history and impacts of environmental racism and the evolution of the environmental movement. It finds that not only have the burdens of environmental degradation been disproportionately distributed across different communities, but that analyses of the ecological impacts of imperialism have created a singular discourse that is paradigmatic of colonial ideologies. It parallels the colonial vision of conservation in North America with the treatment of its Indigenous populations and explores nature as something portrayed as the antithesis of culture. Finally, further examination of the changes from the Trump to Biden administrations is warranted by the construction of a new framework for examining environmental policies, with an emphasis on social equity. The intended outcome of this paper is to create a set of criteria for existing and future environmental legislation.

The Serrasalmidae are a family of Neotropical freshwater fishes that includes carnivorous piranhas as well as their herbivorous relatives, the pacus. Pacu diets consist of leaves, stems, fruits, seeds, and algae, as well as insects, benthic invertebrates, plankton. Likewise, some piranha species are actually more omnivorous than carnivorous, feeding on fruits and seeds in particular and only to a lesser degree the fins and scales of other fishes. These diverse prey materials appear concomitant with diverse jaws and dentitions in both pacus and piranhas, suggesting that some species are ecomorphologically specialized for feeding on certain prey. We investigated how the pattern and tempo of feeding morphological specialization in herbivorous serrasalmids reflects the ecological diversity of their food resources. Pacu and piranha species were first categorized as either algivores, frugivores, folivores, phytophages, planktivores, or omnivores based on a meta-analysis of published gut content data. We used computed tomography (CT) scanning and morphometrics to describe the primary morphological axes of jaw and dental variation and any correlates these phenotypes may have with each species’ primary prey. We found significant differences in the occlusional offset, mechanical advantage, size and shape of the lower jaw among different diet guilds. Phytophages tended to have scissor-like dental occlusion, resembling piranhas more than other pacus. We also found significant differences in the rate of morphological evolution among different diet guilds, notably folivores had morphological rates over 40 times faster than that of planktivores, suggesting different selective regimes acting on each dietary guild.

Polymers are commonly seen in our daily lives. Proteins and plastics are both familiar classes of polymeric materials whose utility is heavily relied upon. There are different architectures of polymers, for instance, linear and cyclic, each of which has unique properties. For example, cyclic polymers have a lower viscosity, smaller hydrodynamic volume, and a unique topology as an endless circle. In this project, we are investigating and improving a privileged method to approach cyclic polymers, Ring Expansion-Metathesis Polymerization (REMP), which grows the polymer chain while cyclizing it, using a Ruthenium-based (Ru) system. The goal of the research is to solve the recent major challenge of synthesizing cyclic polymers in a controlled fashion, through systematically modifying the structure of Ru-based initiators. My goal in the research project is to synthesize a precursor ligand, the subsequent initiator, and the monomers(commonly strained alkenes, norbornene). Eventually using the monomers to conduct polymerization reactions and analyze their properties and characteristics with spectroscopic instruments. Preliminary results of this research suggest we can make cyclic polymers that are more evenly distributed in size and weight. Since polymers have played an important role in people’s everyday life, improving the methodology through having better control on making cyclic polymers can make a big contribution to applications in the aspects of biomedicine and energy for our society. For example, cyclic polymers could generate biotherapeutics for the field of medicine; they could also serve as well-behaved and new types of conducting materials for the field of semiconductor.