Prabin Rai

Fluorescent dyes are critical components in modern biological imaging, both in vivo and in vitro, enabling high-resolution visualization of cellular structures, dynamics, and molecular interactions. This work focuses on the design, synthesis, characterization, and potential applications of some established fluorescent dyes with modifications, along with newly developed helicene fluorescent dyes. Despite extensive past studies of rhodamine dyes, there remain ample opportunities to improve their photostability, quantum yield, water solubility, and incorporation of bio-tagging units. The newly developed semi-helicene fluorophores feature unique structural characteristics that may be responsible for their photo-resistance (currently under investigation). Their red-shifted absorption makes these dyes particularly interesting for cellular imaging. These novel dyes exhibit exceptional brightness, great photostability, and potential circular dichroism responses, making them valuable for stereochemical studies in biological systems. The synthesis of these semi-helicenes was achieved using a microwave reactor rather than conventional methods. The systematic incorporation of electron-donating groups, along with water-soluble units for biocompatibility, is in progress. While there are limited examples of helicene-class dyes used for cell imaging purposes, the work presented here demonstrates their suitability for cellular imaging applications.

Hannah Mitchell

Objective: The aim of this project is to produce high-quality annotations of a 95,000 base pair region of D. willistoni chromosome III.

Methods: This research involved a comparative analysis using databases such as Flybase, the GEP genome browser, and NCBI Blast, with D. melanogaster serving as the reference organism.

Results: Two potential orthologous genes in D. willistoni were identified. D. melanogaster nyo  gene was orthologous to D. willistoni contig37.001.1 and D. melanogaster mey gene was orthologous to D. willistoni contig37.002.1. This annotation of D. willistoni orthologs revealed the same quantity and length of coding regions as compared to D. melanogaster.

Conclusion: These findings suggest that these previously unmapped genes in D. willistoni may share similar functionality with their D. melanogaster counterparts. This investigation provides an opportunity.   to further examine the evolutionary changes in genes in the Drosophila genus, further contributing to the understanding of eukaryotic gene structure and function.

Christopher Beachy, Tyler Brock, Carlos Camp

We collected larvae of the Patch-nosed Salamander, Urspelerpes brucei, and analyzed size-frequency distributions throughout a 12-mo cycle to determine the length of the larval period and size at metamorphosis. The hatchling-size class entered the population across a wide time window, from early winter to late summer, and at a minimal size of 6 mm snout–girdle length (SGL). Examination of both pooled total sample and the samples across six seasonal periods strongly show that the typical larval period is approximately 24 mo with metamorphosis occurring during late summer to early fall at 18–19 mm SGL. Because oviposition and hatching are extended across several months, it is possible that some animals metamorphose up to 30 mo after hatching. Larval growth in Urspelerpes is 0.5 mm/mo, which is comparable—and even slower—to the slow larval growth seen in all other stream-dwelling plethodontid larvae. Our samples of recently metamorphosed animals and mature adults indicate that males are sexually mature at metamorphosis. This is more difficult to know for females, and we suggest that females may be a mixed group that contains individuals that mature at metamorphosis and individuals that delay maturation for an additional 12 mo. There is no difference in either sex between body size at metamorphosis and at sexual maturation. As in other species in the Spelerpini, the timing of metamorphosis and the timing of sexual maturation appear to be able to evolve independently, with the rema

Abby Klahs, Christopher Beachy

Salamander larvae exhibit a high degree of phenotypic plasticity. Their external gills, which enhance respiratory surface area, vary significantly with environmental conditions. Previous studies suggest that low-water flow promotes the development of larger gill structures. To investigate this, we raised Ambystoma mexicanum larvae in both high- and low-flow environments. Using a novel imaging method, we quantified gill size and complexity from both frontal and dorsal perspectives. We hypothesize that larvae in high-flow conditions develop smaller gills because the energetic costs of maintaining large gills may outweigh their benefits in oxygen-rich environments. We also predict that larvae returned to a low-flow environment will regenerate larger gills, though this ability may depend on prior acclimation to low-flow conditions. This study provides insight into the plasticity and reversibility of gill morphology in response to environmental changes, contributing to our understanding of respiratory adaptations in aquatic amphibians.

Mark Merchant, Sarah Baker

Diamondback terrapins (DBTs, Malaclemys terrapin) are sexually dimorphic estuarine turtles that inhabit coastal marshes from Texas to New Jersey. Female DBTs exhibit much larger heads than males and, as a result, also exert much larger bite forces. Periwinkle snails (Littorina littoria) are abundant in coastal marsh habitat and it has been theorized that females ingest these snails to acquire calcium for eggshell development. We collected fecal material from DBTs and employed DNA metabarcoding techniques to analyze the diets of males, subadult females, and adult females from February to August. We found all DBTs consumed marine algae almost exclusively during February and March. However, the diets of adult females increased in snails in April (49%) and May (65%), and then decreased to 31% and 6% in June and July, respectively. This coincides with the mating period of these animals (April-June). In contrast, the diets of subadult female and male DBTs contained very low amounts of snails (≤ 3%) during the entire study period. Both subadult female and male DBTs consumed large amounts of crabs and moderate amounts of fish from April-August. Our data suggests that larger head sizes in breeding female DBTs allow them to consume more snails, increasing available calcium during egg development. 

Harry Meyer, Kathy Jackson, Infeanyi Nkwoka

Tardigrades are microscopic, segmented, eight-legged arthropod relatives often found in moss or lichen.  Diploechiniscus oihonnae, the type species for the genus, is European.  Diploechiniscus horningi, from Oregon and British Columbia, was later added to the genus. Based on morphological criteria using light microscopy, D. horningi was suppressed in 2021 as indistinguishable from D. oihonnae. Specimens we collected from Virginia, while similar morphologically to D. oihonnae, are 13-18% different in COI distance from Europeans, and therefore a different species. Without molecular data we could not be certain that it was a different species than the Oregon population. Italian and Canadian tardigradologists later collected many Diploechiniscus from British Columbia. In 2024 they described a new, morphologically distinct species, D. dimorphus, and established from molecular data that D. horningi is a valid species. We have determined that Virginia specimens are a different species than D. horningi and D. dimorphus (25-32% COI distances). A closer morphological examination also revealed that the cuticle pattern in Virginia population differs in some ways from the pattern in D. oihonnae and D. horningi. The Virginians also differ morphologically from two Japanese species recently attributed to the genus, for which no molecular data are available. We conclude that we now have sufficient evidence to describe the Virginia population as a new species of Diploechiniscus.

Jasmine Nasser

Amphibians are ectotherms and can respond to changes in environmental temperatures by behavioral thermoregulation in thermal gradients. Ectotherms thermoregulate to exploit thermally diverse environments while maintaining control of certain physiological processes. One way many species regulate body temperature is by selecting appropriate microhabitats.

In salamanders, thermal biology is still widely unknown as the literature on this topic is sparse compared to other ectothermic organisms. Furthermore, in the few studies focused on salamander thermoregulation, salamanders are exposed to artificial thermal gradient temperatures that extend beyond temperatures found in the field and ectothermic animals often neglect to thermoregulate in artificial settings.

In this study, I will investigate the behavioral thermoregulation of the plethodontid salamander Eurycea cirrigera using their thermal preferences as an indication of their thermoregulation and test if these behaviors, like thermal preference, are likely genetically or environmentally derived.

Gretchen Shirey, Christopher Beachy, Kyle Piller, Matthew Niemiller

Developing non-invasive methodological approaches is of great importance when working with sensitive populations and species. Environmental DNA (eDNA) has become an effective tool for the study of rare, threatened, and endangered species across many aquatic and terrestrial ecosystems. Environmental DNA assays are non-destructive so they are particularly attractive for species residing in habitats that are difficult to access or sample. The Georgia Blind Cave Salamander (Eurycea wallacei) inhabits karst environments that are often inaccessible due to the need for cave-diving experience or simply the physical and structural inability to access the submerged groundwater systems. Monitoring population trends of species that are difficult to detect and survey may be substantially more practical with an eDNA approach. Here we conducted a field survey using an eDNA assay in highly sensitive, understudied habitat within the Floridian Aquifer. Water samples were collected from twelve sites within one cave system near Marianna, Florida. To evaluate eDNA detection thresholds across horizontal distances into each cave entrance, we sampled within the cave, at the vent of the cave, and at the surface above the vent. We amplified a fragment of the cytochrome c oxidase subunit 1 (COI) gene using a previously developed set of metazoan primers. The results from our first and second sampling seasons will be presented. Assessing the presence of Eurycea wallacei in different habitats of this cave