The Effect of Nicotine and Cotinine on the Development of Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae)

Nicotine, readily available in electronic nicotine delivery systems, poses a lethal threat as it is easily accessible and highly toxic in its liquid form. Seventy-five percent of nicotine is metabolized into cotinine, and with the growing prevalence of nicotine-related deaths comes the increased possibility of finding nicotine or cotinine in the tissues of a corpse and thus the possibility of distorting the postmortem interval (PMI). Through entomotoxicology, the study of how drugs and toxins influence the development of insects present on a decomposing body, this experiment aimed to determine if varying levels of nicotine and cotinine affect the development of the forensically important Cochliomyia macellaria (Fabricius) [Diptera: Calliphoridae]. In this experiment, C. macellaria maggots were reared on seven varying concentrations of nicotine and cotinine and were sampled every eight hours. Length, weight and accumulated degree hours were then measured or determined. Our study found that maggots reared on lethal nicotine and lethal cotinine showed a significant decrease in length and weight as well as a delay in development time for the second instar life stage. These results suggest a relationship between high concentrations of nicotine and cotinine and the development of C. macellaria, which could greatly affect PMI estimations.Biography: Elise Hodges, Tessa Fungo, Gautham, and Hannah Bowlin are undergraduate honor’s students who conducted a research project in the field of forensic entomology as a part of Dr. Heather Ketchum’s perspectives course, “Bugs, Thugs, and Science” in fall 2018.University Libraries Undergraduate Research Awardundergraduat

Heterochromatic breaks move to the nuclear periphery to continue recombinational repair

Heterochromatin mostly comprises repeated sequences prone to harmful ectopic recombination during double-strand break (DSB) repair. In Drosophila cells, ‘safe’ homologous recombination (HR) repair of heterochromatic breaks relies on a specialized pathway that relocalizes damaged sequences away from the heterochromatin domain before strand invasion. Here we show that heterochromatic DSBs move to the nuclear periphery to continue HR repair. Relocalization depends on nuclear pore and inner nuclear membrane proteins (INMPs) that anchor repair sites to the nuclear periphery via the Smc5/6-interacting proteins STUbL/RENi. Both the initial block to HR progression inside the heterochromatin domain, and the targeting of repair sites to the nuclear periphery, rely on SUMO and SUMO E3 ligases. This study reveals a critical role for SUMOylation in the spatial and temporal regulation of HR repair in heterochromatin, and identifies the nuclear periphery as a specialized site for heterochromatin repair in a multicellular eukaryote