Session C: Innovative Scientific Discoveries

The preoptic area (POA) of the hypothalamus is integral to regulating social behavior and emotional responses, acting as a central node within the brain’s social and emotional networks. Dopamine (DA) is key to social behaviors, though poorly studied in Amatitlania nigrofasciata, a monogamous species with strong biparental care, which offers an ideal model for investigating the neurobiology of social bonding. This study examines Tyrosine Hydroxylase (TH), a marker for DA neurons, and Dopamine Receptor 2 (D2R) across three fish species with differing social behaviors: A. nigrofasciata (monogamous with biparental care), Mchenga conophorus, and Danio rerio (both non-pair bonding with no biparental care). We hypothesized that increased TH-positive neurons in the POA during embryonic development are associated with monogamy, suggesting that TH expression in the POA contributes to the evolution of pair bonding through neurodevelopmental plasticity. Using single in situ hybridization, we examined TH expression, later

Chronic pulmonary infections with Pseudomonas aeruginosa is a major cause of loss of lung function in people with cystic fibrosis (pwCF). Intrastrain P. aeruginosa population genetic heterogeneity in CF airways is well known, but the effects of this intrastrain genetic and phenotypic heterogeneity on antimicrobial resistance and pathogenesis are not known. Here we aimed to determine how prolonged antibiotic treatments affect the P. aeruginosa population structure and dynamics over time. To examine this, we collected whole Pseudomonas populations from expectorated sputum samples of three adult pwCF over two years as part of routine clinic visits. We then isolated 81 colonies from each sputum sample. We found fourteen distinct colony morphotypes across all three samples over time, with a single morphotype dominating in each sputum sample. To determine the intrastrain population structure and dynamics, we deep sequenced (300x coverage) whole P. aeruginosa populations and examined the changes in allele frequency and genetic heterogeneity in each sputum sample and its impact on antimicrobial resistance and lung function. We found an increase in allele frequency of genes involved in genetic regulation and transcription. This research provides novel insights into intrastrain P. aeruginosa population dynamics and underscores the role that each member of the population plays in resisting prolong antimicrobial treatments and damage to the airways.

High fat consumption is detrimental for brain health and cognition. Fibroblast growth factor 21 (FGF21) is elevated in response to an HFD. Administration of FGF21 improves central health in preclinical models. The role of endogenous FGF21 in protecting the brain against an HFD remains unexplored. This study aimed to identify whether endogenous FGF21 aids in protecting the brain against HFD-induced cognitive impairments and brain dysfunction in both sexes. Male and female wild-type (WT) and FGF21 knockout (Fgf21-/-) mice followed a chow (13.6% fat) or HFD (60% fat) for 9 weeks (n = 7-8, diet x genotype x sex). Body weight was measured weekly. Serum FGF21 was measured by ELISA. Cognition was assessed by novel object recognition test, Barnes maze, and fear conditioning. Protein was isolated from whole brain and hippocampus and was measured by western blot. HFD feeding increased body weight of all mice and increased FGF21 in WT mice. HFD decreased recognition memory of WT mice, while recognition memory was decreased in Fgf21-/- mice independent of diet(s). HFD impaired spatial learning and memory of WT males. HFD had no effect on associative cognition, regardless of sex and Fgf21-/- mice spent more time frozen overall. HFD increased SIRT1 and NOX2 in the brain of WT males, but not females. Whereas IBA1 was elevated in the hippocampus of WT males only. Our data suggest that increased endogenous FGF21 in response to HFD intake does not protect against HFD-induced cognitive impairments or brain dysfunction.

We present a transform method to analyze the erosion of a porous medium with multiple cylindrical bodies. Our study focuses on a two-dimensional channel geometry containing an array of cylinders of varying sizes and arbitrary locations. We solve the associated boundary value problem for the biharmonic equation using our transform method, which provides quasi-analytical solutions and leads to fast and accurate schemes for evaluating the solutions. Specifically, our model considers cases based on the threshold law, where erosion occurs when the total shear stress exceeds a specified critical value dependent on the material of the cylindrical bodies. This erosion process not only reduces the size of the cylindrical bodies but also alters their shapes, causing them to shrink and eventually vanish in finite time. We compute the shear stress on the cylinders and use it to determine the updated shapes of the eroded bodies.