Project description:Sensory systems of many organisms display periodic adjustments to accommodate cyclical changes in the local environmental conditions. Seasonal fluctuations in visual perception are documented in many species, including humans, but the mechanisms and ecological significance of these adaptations often remain obscure. Depsite limited knowledge of bat visual ecology relative to hearing, the diversity of bat species makes them useful models for studying sensory adaptation mechanisms. Here we analyze daily and seasonal changes in gene expression in the eyes of a temperate echolocating bat, the Mexican free-tailed bat (Tadarida brasiliensis). A total of 44 wild-caught bats were sampled from the same location across all four seasons, with whole eyes sequenced for total mRNA expression. Expression patterns were analyzed using differential expression analysis and clustering techniques for identifying correlation networks and evidence of cyclical enrichment. Additionally, a target gene list representing key physiological processes was applies to assess which biological pathways displayed the most robust seasonal or daily changes. 17.8% of genes showed significant differential expression based on season, compared to 11.5% of genes for daily expression. Several gene networks related to the circadian clock, phototransduction, and metabolic function displayed significant rhythmic seasonal effects. Quantum catch modeling indicates higher photon capture potential in summer based on weighted opsin expression, consistent with an adaptive response to lower twilight irradiance. Seasonal remodeling of the ocular transcriptome is consistent with enhanced phototransduction in summer, suggesting vision may play a greater role during this period.
Project description:SARS-CoV-2 emerged in humans in late 2019 and was rapidly followed by spillback into naive wildlife, leading to both mortality events and novel enzootic cycles. Of special concern is whether SARS-CoV-2 could establish in bats in the Americas, given that sarbecoviruses coevolved with rhinolophid bats in the Eastern Hemisphere. We analyzed residual plasma samples from a previous SARS-CoV-2 challenge study of Mexican free-tailed bats (Tadarida brasiliensis) to identify candidate protein biomarkers of susceptibility and assessed the abundance of these same proteins in a wild population of this bat species in Texas. Using 2 uL plasma volumes, we generated proteomes from captive (n = 20; four resistant, five susceptible, 11 unchallenged) and wild (n = 15) bats using the S-Trap method and LC-MS/MS, identifying 475 proteins using data-independent acquisition and a species-specific genome annotation generated by the Bat1K Project.