Tag: Poster 60

Age-Related Differences in Healthy Male Runners

Presenter: Justine Silberberg

Mentors: JJ Hannigan and Li-Shan Chou, Human Physiology

Poster: 60

Major: Human Physiology

Previous research suggests that older males display less ankle plantar flexion and greater hip flexion during gait compared to younger individuals. Differences in running gait between younger and older individuals, however, are largely unknown. This study investigated differences in strength, flexibility, and range of motion between younger runners (n = 15; age range = 18-21) and older runners (n = 10; age range = 40-51). All subjects were males who ran at least 20 miles per week. For testing, subjects ran continuous laps of approximately 40-meters in the Motion Analysis Laboratory. Running kinematics were collected using a 10-camera motion capture system, strength was measured using a Biodex System 3 dynamometer, and flexibility was measured statically by a trained clinician. Independent sample t-tests were used to examine group differences. Older individuals were found to have increased hamstring flexibility, increased first metatarsal-phalangeal joint range of motion, decreased quadriceps flexibility, and decreased trunk flexion compared to younger runners (p < 0.01). Limitations include the relatively small sample size and cross-sectional nature of this study. Understanding age-related differences in running gait may help clinicians better treat injuries in older runners. Future studies exploring age-related differences in running should recruit a wider age range and follow these individuals over time.

A Screen for Novel Atypical Protein kinase C (aPKC) Substrates

Presenter: Alani Estrella

Co-Presenters: Ken Prehoda, Matt Bailey

Presentation Type: Poster 60

Primary Research Area: Science

Major: Biochemistry

The accurate positioning and organization of molecules within animal cells is important for cell health. In fact, failure to correctly organize cell components is a key characteristic of metastatic cancers. Atypical protein kinase C (aPKC) is an enzyme that helps to properly localize a variety of cell components through a process called phosphorylation. The proteins that aPKC phosphorylates (known as substrates) have vastly different architectures. Although the phosphorylation of specific substrates has been researched intensely, such as Miranda (Mira) and Lethal giant larvae (Lgl), the general mechanism of aPKC substrate localization has remained elusive. Here, we sought to find a “polarity code,” or the molecular signature of substrates that aPKC organizes. To identify the polarity code, we developed a program that predicts novel aPKC substrates. Here we assessed the localization of these putative substrates to determine candidates for aPKC-regulated localization in fruit flies. We used a protein tagging technique that allows us to see protein expression and localization within brain cells. We observed the localization of three separate proteins: Alpha-Catenin, Dlp, and CG6454 to be cell-cycle dependent, suggesting possible aPKC-regulation. Future studies will focus on determining the mechanism through which these proteins are localized, whether aPKC is involved, and their roles in cell polarity. This study provides insight into how aPKC recognizes its substrates, and a further understanding of how animal cell components are organized by aPKC.

Ontogenetic Shifts in Resource Use And Behavior in the Striped Parrotfish, Scarus Iseri, on a Patch Reef in Bocas Del Toro, Panama

Presenter(s): Haley Faringer − Environmental Science

Co Presenter(s): Rulon Hardy, Christina Ellison

Faculty Mentor(s): Richard Emlet, Jan Hodder

Poster 60

Research Area: Natural/Physical Science, Marine Biology, Ecology

Scarus iseri, the striped parrotfish, is among the most abundant parrotfish on Caribbean coral reefs. As grazing herbivores, they shape community structure by transmitting primary production up the food chain, regulating algal biomass, and facilitating benthic settlers in the process of removing patches of algae. S. iseri are protogynous hermaphrodites with 3 life stages (juvenile, initial and terminal) identifiable in the field. Our study investigates differences in range size, habitat utilization, and behavior between the juvenile and terminal phases. Through this research, we hoped to gain a better understanding of how these fish utilize their habitat as they grow, and how resources are partitioned among members of a population.

Our research was conducted at House Reef, near the Smithsonian’s Tropical Research Institute in Bocas del Toro, Panama. We followed 6 focal individuals of each life stage for a 15-minute period to establish their range. These parameters were chosen due to time constraints of the study period. We only had 4 days to complete the research, including data analysis, and wanted to maximize both the amount of time we followed each fish, and the number of replicates for each life stage. The numbers we chose reflect a compromise between these two variables. Using survey flags and transect-tape, we calculated the area of each range and drew a map of its shape.

Before conducting surveys in the field, we constructed an ethogram, or a table of observed behaviors for the fish. Then for 5 minutes of the 15-minute period we observed and recorded behaviors of the fish according to our ethogram. This allowed us to gain insight about feeding frequency, substrate used for feeding (e.g. sediment, sponge, sand, etc.), the proportion of each type of substrate used, and social behavior within a population.

Our results suggest that range size increases with more advanced life stage. Time allocations for feeding and non-feeding behaviors are similar between the two stages and both life stages utilize the same substrate types for feeding, in similar proportions. Juveniles frequently form groups, while terminal phase individuals are often found alone.

Because Scarus iseri is so prominent in the Caribbean Ocean, it has an increased ability to transfer nutrients through trophic levels. Not only is it important to understand how resource utilization within this species is affected by life stage, but how this resource utilization affects nutrient levels and habitat availability for other species on reefs of the Caribbean Ocean. With the recognition of variable social behaviors and range sizes between juveniles and terminal adults, we hope to better understand the nature of these fish’s relationship with each other and other stakeholders on the reef. The data collected is important because it can be used to inform the management of marine protected areas aimed at preserving this important group of fish.

The Development of a System to Determine the Size Dependence of In2O3 Nanocatalysts on CO2 Reduction

Presenter(s): Casey Bisted

Faculty Mentor(s): James Hutchison & Tawney Knecht

Poster 60

Session: Sciences

The increase of carbon dioxide in the atmosphere has caused irreversible environmental effects, so reduction of this atmospheric carbon dioxide is necessary to prevent further environmental damage. Nano-catalysts are a promising new avenue in green chemistry as their small size and large surface area allows for less material usage as well as potentially superior chemical properties compared to their bulk counterparts. Bulk In2O3 has basis as a promising carbon dioxide reduction catalyst due to it being a poor hydrogen evolution reaction catalyst. Thus, In2O3 nanoparticles could be promising in carbon dioxide reduction.

By molecularly linking In2O3 nanoparticles to a boron doped diamond electrode via a molecular linker, the size dependence of In2O3 nanoparticles on the reduction of carbon dioxide can be determined. To enable this size dependence testing, a system to test this size dependence is developed and assembled. This system consists of In2O3 nanoparticles bound to a boron doped diamond electrode via an amine terminated carbon chain electrodeposited onto the boron doped diamond. It is hypothesized that smaller In2O3 nanoparticles will be more efficient carbon dioxide catalysts due to their increased surface area to volume ratio that promote a larger amount of active sites.Knowledge of the carbon dioxide reduction activity of a size range of In2O3 fills in a piece of the puzzle of about how to eliminate atmospheric carbon dioxide and reduce climate change effects.