Senior Research Presentations

Isabella Jessee, Investigating the Antimicrobial Properties of Multifloral Honey in Southwestern Virginia Under the Direction of Dr. Mary Jane Carmichael The antimicrobial properties in multifloral honey have been utilized for centuries in wound healing, as well as infection treatment and prevention. The chemical properties from the nectar source, enzymes produced by the bee, as well as the digestive activity of the microorganisms in the bee gut all contribute to the antimicrobial activity of honey. Honeybee farms in four locations across southwestern Virginia (Fincastle, Covington, Troutville, and Martinsville) were visited in the fall of 2021 to collect honey (fall and spring), worker bees, and pollen pellets. Disk diffusion assays were used to assess the antimicrobial activity of fall and spring honey against ESKAPE pathogens. Zones of inhibition of fall and spring honeys across sites closely matched that of Manuka honey, which was used as a positive control in assays due to its potent antimicrobial activity. Pollen analysis was completed on the spring honey and fall pollen pellets to identify the plant species on which the bees were foraging at each time of year. Fincastle had the most species diversity across sites and among all spring honey. Fincastle and Troutville had the most species diversity across sites and among all fall pollen pellets. Lastly, the honeybee gut was dissected, and the microorganisms within the midgut and hindgut were isolated and identified using 16S rRNA gene sequencing to identify the cultivable microbial community in the bee gut. There were 10 species identified across sample sites, including Bacillus megaterium, Paenibacillus alvei, Bacillus thuringiensis, Bacillus anthracis, Bacillus mycoides, Serratia marcescens, pantoea vagans, Bacillus weidmannii, Bacillus cereus, and Pantoea agglomerans. The products of these microbes, the variance in pollen source, and other chemicals have supplied mutlifloral honey in southwestern Virginia with its antimicrobial properties. Zoë Jordan, Anthropogenic Noise and its Impacts on Plants, Pollinators, and People Under the Direction of Dr. Renee Godard Recent studies have shown that anthropogenic noise can have significant impacts on the species composition of ecosystems, plant physiology, animal behavior, and physiology in addition to acute and chronic impacts on human health and well-being. While past studies have examined impacts on different organisms separately and often in the lab, this study compared responses of pollinators, plants, and people exposed to two different locations (HT - high traffic and LT - low traffic) separated by 200 m on the Hollins University Campus. Average noise levels at the HT site were 10dB louder than at the LT site with the average maximum levels greater than 90bB. Unlike previous studies, we found that the above and below-ground biomass of HT plants and LT plants grown in microcosms did not differ nor was there any difference in leaf stomatal density after 58 days. Before harvesting, pollinator visitation rates at the microcosms at both sites (HT & LT) were videotaped simultaneously on five different occasions. Analysis of these videos revealed no difference in visitation rates by pollinators between the LT and HT sites; however, greater diversity in pollinator taxa was seen on marigolds at the LT site during July. To explore human responses, 44 participants spent 15 mins seated at both sites with a visual barrier blocking the roads. These exposures were separated by at least 24 hr, and participant blood pressure was measured, before and after the 15-min exposure. In addition, participants completed the PANAS survey after each exposure. Overall, participant blood pressure dropped after the 15 min exposure in both sites, with a significantly greater drop in systolic blood pressure found at the LT site. Participants also had lower “negative PANAS scores” at the LT site. This multilayered field study indicated that noise does matter and can have impacts on multiple species and processes within a system