The involvement of mitochondria and the respiratory chain in aging is well established, and reports have uncovered the role of the nervous system in this process. To address whether particular neurons are important in determining longevity, we targeted the genetic components of complex IV and V in the respiratory chain by RNA inhibition (RNAi) in specific subsets of the Drosophila nervous system. We discovered that simultaneous interference in both serotonergic and dopaminergic neurons or selective interference in neurons expressing the serotonin receptor d5-HT1b leads to shortened Drosophila life span. No differences in life span were observed when RNAi was targeted exclusively to dopaminergic neurons or octopamine/tyramine neurons. Neuronal subtype was a very important factor in our experiments, and this study begins to offer clues as to which neurons might mediate longevity in a cell non-autonomous fashion.

The Brine Shrimp Lethality Assay (BSLA) is a rapid and economical assay that has been used to screen plant extracts for potential anti-tumor compounds. The objective of this study was to screen Mid-Michigan plant extracts for activity in the BSLA to identify candidates for further pharmacological study. Based on the knowledge that many plants found in the region have been used in Native American traditional medicine for a variety of conditions, including cancer, we hypothesized that some plants would demonstrate activity in the BSLA. In addition, we aimed to determine any difference in sensitivity between the traditional test tube format and the more recently developed microwell format of the assay. After a preliminary screening of 38 plant extracts, eight extracts were active in the BSLA, including Achillea millefolium, Nepeta cataria, and Podophyllum peltatum. Both A. millefolium and N. cataria have been used as cold remedies in Native American traditional medicine, while P. peltatum derivatives etoposide and teniposide are current anti-tumor drugs. We also demonstrated that the sensitivity of the assay is dependent on the assay format. Percent lethality was higher in the 96-well plate format when compared to the 5 mL glass test tube format. These results suggest that several plants from the Mid-Michigan region may be worthy of further investigation to characterize their biological activity as it relates to potential anti-cancer properties. Furthermore, we suggest that researchers use the 96-well BSLA format to increase sensitivity and inter-laboratory consistency of the assay.

Transcription factors are crucial for proper gene expression because they coordinate temporal and spatial transcription. Lhx1a is a transcription factor belonging to the LIM homeodomain (LIM-HD) family and plays vital roles in development of the kidney and nervous system. It is expressed in zebrafish kidney stem cells during development and regeneration. It was previously showed that Lhx1a dimerizes with itself in a yeast two-hybrid system, and hypothesized that dimerization is important for its transcriptional activity. Identifying the dimerization domain would be valuable in probing the molecular function of lhx1a. Here, it is shown that the linker region is neither necessary nor sufficient for dimerization, and thus it is not the dimerization domain. Understanding the molecular function of Lhx1a could lead to strategies for manipulating its activity in kidney stem cells to enhance kidney regeneration.

Phenotypic plasticity is the ability of an organism to adjust morphology and/or physiology in response to environmental variation. Hydrocotyle bonariensis is a perennial herb found in both coastal sand dune and inland habitats of coastal Georgia. The soil types of these two habitats differ in both soil characteristics and soil chemistry. The purpose of this study was to explore potential phenotypic plasticity in H. bonariensis in response to two different soil types by comparing leaf and petiole morphology and stomata density and length between individuals grown in soil from a sand dune habitat and soil from an inland coastal habitat. Results showed significantly greater leaf area, petiole fresh weight, petiole thickness, and petiole length in individuals grown in inland soil compared to sand dune soil. Furthermore, the density of stomata on bottom leaf surfaces was significantly greater in plants grown in inland soil, and the length of stomata on the top and bottom leaf surfaces was significantly greater in plants grown in sand dune soil. These results suggest that the differences in soil texture, and subsequent differences in waterholding capacity and nutrient availability, likely led to the observed differences in leaf and petiole morphology, while differences in stomata density and length may represent a phenotypic plastic response in this species to soil type. The ability of H. bonariensis to respond plastically to changes in environmental conditions, such as variations in soil type, likely plays an important role in its ability to successfully thrive in multiple habitats in Georgia.

Mosquito-borne infectious diseases such as malaria, dengue fever, chikungunya, and zika are responsible for hundreds of thousands of deaths across the globe each year. Due to the nature of the viruses and parasites that cause these diseases, targeting their mosquito vectors has become the most effective method for reducing transmission. However, an ecologically and evolutionarily sustainable method for mosquito population reduction has yet to be developed. This may be about to change due to the proven effectiveness of genome editing in mosquitoes using the CRISPR/Cas9 system. CRISPR/Cas9, found in nature as the adaptive immune system of bacteria and now adapted as a biological tool for use in any organism, is revolutionizing the study of genetics and now may also be the key to ending a global public health crisis. Current population control methods utilizing transgenic mosquitoes have ultimately failed at the hands of evolution due to unintended fitness costs. Here, we propose a novel control method for the invasive vector mosquito species, Aedes albopictus, using CRISPR/Cas9 to target genes that are essential for a period of developmental arrest known as photoperiodic diapause. Since diapause allows the species to invade temperate regions, genetic disruption of this pathway should result in the inability of Ae. albopictus to inhabit temperate environments, which in turn should inhibit the spread of mosquito-borne diseases in these regions.