Elizabeth DiBona

The National Science Foundation-funded Research Traineeship on Stakeholder-Guided Environmental Science (STAGES) at Texas A&M University-Corpus Christi aims to improve interdisciplinary and transdisciplinary collaborative science and communication through a combination of hands-on, experiential training and coursework for graduate students. A core feature of this program is the Headwaters to the Ocean (H2O) field trip, which immerses students in practical interdisciplinary research and data collection within the Nueces River watershed. The field trip spans the river from its headwaters near Uvalde, Texas, to Nueces Bay, with students studying various environmental indicators such as water chemistry, air pollution, hydrogeologic setting, and microplastics to assess the impacts of human activities. Through these experiences, STAGES seeks to build a common language among participants from diverse scientific backgrounds, ultimately fostering more effective research collaborations and preparing students for complex environmental science challenges. The STAGES program also offers recommendations for improving interdisciplinary teamwork, enhancing communication, and refining project planning, making it a model for training future scientists in integrated environmental science approaches.

The prevalence of chronic inflammation increases with age and may be aggravated by environmental exposures. Similarly, during immune aging, inflammatory disease incidence increases as protective immunity decreases. To better understand disease and exposure risks, an immune aging model outlining key changes in immune function is crucial. Utilizing the lowest possible vertebrate class, we propose the Japanese medaka (Oryzias latipes) as a model to investigate sex-specific immune aging including changes in immune gene expression, leukocyte profiles, and organismal level immune response. Evaluating the expression of immune initiators (CRP, TLR5-s, TLR5-m, TCRb, and MHCII), immune mediators (MYD88, Nf-kß, C3, and IL1b), and immune effectors (LYZ and C8) in concomitance with alterations in leukocyte populations and host resistance to pathogens will inform about immune competence across ages. The data presented here demonstrate a critical decrease in the expression of immune initiators (CRP, TLR5-soluble, TCRb, and MHCII), mediators (MYD88, Nf-kß, C3, and IL1b), and effector (LYZ) in both females and males after 11 months post hatching (mph). Interestingly, both sexes displayed an upregulation for the immune effector, C8, during this older life stage (11–13 mph). Gene expression profiles for both sexes at the most elderly age (20 or 23 mph) appear to revert to a younger profile of expression indicating a second change in immune function during aging rather than a steady decline. Significant changes in leukocyte populations were observed in both male and female medaka after peaking sexual maturation at 3 mph. Organismal level immune competence data revealed male medaka at the elderly age to be more vulnerable than their female and younger male counterparts while no differences were observed in females based on age. Together, these data provide a holistic profile for immune aging in medaka, a useful tool for future immunological studies considering age as a factor influencing disease susceptibility.

Southern flounder skin pigmentation is a critical phenotypic characteristic for this species’ survival in the natural environment. Normal pigmentation allows rapid changes of color for concealment to capture prey and UV light protection. In contrast, highly visible hypopigmented pseudo-albinos exhibit a compromised immune system and are vulnerable to predation, sensitive to UV exposure, and likely have poor survival in the wild. Skin and brain tissue samples from normally pigmented and hypopigmented individuals were analyzed with next-generation RNA sequencing. A total of 1,589,613 transcripts were used to identify 952,825 genes to assemble a de novo transcriptome, with 99.43% of genes mapped to the assembly. Differential gene expression and gene enrichment analysis of contrasting tissues and phenotypes revealed that pseudo-albino individuals appeared more susceptible to environmental stress, UV light exposure, hypoxia, and osmotic stress. The pseudo-albinos’ restricted immune response showed upregulated genes linked to cancer development, signaling and response, skin tissue formation, regeneration, and healing. The data indicate that a modified skin collagen structure likely affects melanocyte differentiation and distribution, generating the pseudo-albino phenotype. In addition, the comparison of the brain transcriptome revealed changes in myelination and melanocyte stem cell activity, which may indicate modified brain function, reduced melanocyte migration, and impaired vision.

Microplastic pollution has been recognized as a potential threat to environmental and human health. Recent studies have shown that microplastics reside in all ecosystems and contaminate human food/water sources. Microplastic exposure has been shown to result in adverse effects related to endocrine disruption; however, data are limited regarding how exposure to current environmental levels of microplastics during development may impact reproductive health. To determine the impact of environmentally relevant, chronic, low-dose microplastic fibers on fish reproductive health, juvenile Japanese medaka were exposed to five concentrations of polyethylene fibers for 21 days, and reproductive maturity was examined to assess the later life consequences. Fecundity, fertility, and hatching rate were evaluated to determine the organismal level impacts. Gonadal tissue integrity and stage were assessed to provide insights into potential tissue level changes. Expression of key reproductive genes in male and female gonads provided a molecular level assessment. A significant delay in hatching was observed, indicating cross-generational and organismal level impacts. A significant decrease in 11-beta-dehydrogenase isozyme 2 (HSD11β2) gene expression in male medaka indicated adverse effects at the molecular level. A decrease in male expression of HSD11β2 could have an impact on sperm quality because this enzyme is crucial for conversion of testosterone into the androgen 11-ketotestosterone. Our study is one of the first to demonstrate subtle impacts of virgin microplastic exposure during development on later life reproductive health. The results suggest a possible risk of polyethylene fiber exposure for wild fish during reproductive development, and populations should be monitored closely, specifically in spawning and nursery regions. Environ Toxicol Chem 2022;41:2848–2858. © 2022 SETAC