Evaluating Microplastic Experimental Design and Exposure Studies in Aquatic Organisms

Environmental microplastic particles (MPs) represent a potential threat to many aquatic animals, and experimental exposure studies, when done well, offer a quantitative approach to assess this stress systematically and reliably. While the scientific literature on MP studies in aquatic environments is rapidly growing, there is still much to learn, and this chapter presents a brief overview of some of the successful methods and pitfalls in experimental MP exposure studies. A short overview of some experimental design types and recommendations are also presented. A proper experimental exposure study will yield useful information on MP-organism impacts and must include the following: a comprehensive MP characterization (e.g., density, buoyancy, type, nature, size, shape, concentration, color, degree of weathering/biofilm formation, an assessment of co-contaminant/surfactant toxicity and behavior, an understanding exposure modes, dose and duration, and the type and life stage of the target species). Finally, more conventional experimental considerations, such as time, costs, and access to clean water, specialized instrumentation, and use of appropriate controls, replicate, and robust statistical analyses are also vital. This short review is intended as a necessary first step towards standardization of experimental MP exposure protocols so one can more reliably assess the transport and fate of MP in the aquatic environment as well as their potential impacts on aquatic organisms.

Severe frost but not shade could limit the future growing season of Erythronium americanum

Changes in climate are leading to modifications in the timing of seasonal events such as migrations and flowering. Erythronium americanum (trout lily) can break bud early in response to warming, but changes to its growing season may be limited by early shade from canopy trees and frost. I experimentally assessed the impact of shade and frost on senescence in E. americanum and descriptively monitored the response of E. americanum to vernal air and soil temperatures in a garden setting. Early shade did not affect the timing of senescence. Experimental exposure to frost resulted in increased leaf damage, earlier senescence, and greater corm death than in control plants. Despite ten days in which the air temperature dropped below freezing, there was no evidence of leaf damage in the field. These results suggest that early shade from canopy trees will not hasten the end of the future growing season for E. americanum, but that late frost could bring about early senescence if that frost is sufficiently hard.

What Strategy Is Better for Promoting COVID-19 Vaccination? A Comparison Between Gain-Framed, Loss-Framed, and Altruistic Messages

Background/Objective Vaccination is an efficient public health strategy for controlling infectious diseases like the COVID-19 pandemic. Therefore, this study evaluates the effect of gain-framed, loss-framed, and altruism messages on willingness to get a COVID-19 vaccine and confirms the best strategy for promoting vaccination. Methods Herein, we designed an online survey experiment, including a control (exposure to non-framed information) and three experimental (exposure to gain-framed, loss-framed, or altruistic messages) groups, to assess the vaccination willingness. All participants (n = 1316) were randomly assigned into one of the four groups. Results The individuals exposed to gain-framed, loss-framed, or altruism messages exhibited a higher willingness to get a COVID-19 vaccine than those exposed to non-framed information. Moreover, the loss-framed information effect on vaccination willingness was more substantial than the other two messages. However, no significant difference was observed between the gain-framed and altruism messages. Conclusion This study suggests that a loss-framed information dissemination strategy could be preferable to motivate vaccination willingness against COVID-19.

SARS-CoV-2 evolution in animals suggests mechanisms for rapid variant selection

SARS-CoV-2 spillback from humans into domestic and wild animals has been well-documented. We compared variants of cell culture-expanded SARS-CoV-2 inoculum and virus recovered from four species following experimental exposure. Five nonsynonymous changes in nsp12, S, N and M genes were near fixation in the inoculum, but reverted to wild-type sequences in RNA recovered from dogs, cats and hamsters within 1-3 days post-exposure. Fourteen emergent variants were detected in viruses recovered from animals, including substitutions at spike positions H69, N501, and D614, which also vary in human lineages of concern. The rapidity of in vitro and in vivo SARS-CoV-2 selection reveals residues with functional significance during host-switching, illustrating the potential for spillback reservoir hosts to accelerate evolution, and demonstrating plasticity of viral adaptation in animal models.One-Sentence SummarySARS-CoV-2 variants rapidly arise in non-human hosts, revealing viral evolution and potential risk for human reinfection.