Genetic tools for the study of the mangrove killifish, Kryptolebias marmoratus, an emerging vertebrate model for phenotypic plasticity.

Kryptolebias marmoratus (Kmar), a teleost fish of the order Cyprinodontiformes, has a suite of unique phenotypes and behaviors not observed in other fishes. Many of these phenotypes are discrete and highly plastic-varying over time within an individual, and in some cases reversible. Kmar and its interfertile sister species, K. hermaphroditus, are the only known self-fertile vertebrates. This unusual sexual mode has the potential to provide unique insights into the regulation of vertebrate sexual development, and also lends itself to genetics. Kmar is easily adapted to the lab and requires little maintenance. However, its internal fertilization and small clutch size limits its experimental use. To support Kmar as a genetic model, we compared alternative husbandry techniques to maximize recovery of early cleavage-stage embryos. We find that frequent egg collection enhances yield, and that protease treatment promotes the greatest hatching success. We completed a forward mutagenesis screen and recovered several mutant lines that serve as important tools for genetics in this model. Several will serve as useful viable recessive markers for marking crosses. Importantly, the mutant kissylips lays embryos at twice the rate of wild-type. Combining frequent egg collection with the kissylips mutant background allows for a substantial enhancement of early embryo yield. These improvements were sufficient to allow experimental analysis of early development and the successful mono- and bi-allelic targeted knockout of an endogenous tyrosinase gene with CRISPR/Cas9 nucleases. Collectively, these tools will facilitate modern developmental genetics in this fascinating fish, leading to future insights into the regulation of plasticity.

A Comparative Analysis of Online Versus in-Person Opioid Overdose Awareness and Reversal Training for First-Year Medical Students.

INTRODUCTION: Physicians trained in opioid use disorder (OUD) harm reduction can mitigate opioid overdose deaths by prescribing naloxone and educating patients about its use. Unfortunately, many physicians possess OUD stigma. Training during medical school presents an opportunity to reduce OUD stigma and improve opioid overdose reversal knowledge. This study assessed the efficacy of Opioid Overdose Awareness and Reversal Training (OOART) and evaluated the equivalency of the online and in-person OOART. Methods: Voluntary training was delivered to first-year medical (M1) students at one medical school. In 2018 and 2019, 29 and 68 M1 students, respectively, received in-person OOART training and completed pre- and post-training surveys. In 2020, 62 students participated in online OOART training, of which 53 completed both pre- and post-training surveys. Results: All three opioid overdose Knowledge questions showed significant improvements between pre- and post-training survey responses. For Attitude questions, six of eleven questions in 2019 and 2020 and four of eleven questions in 2018 had statistically significant improvements between pre- and post-training survey responses. There were no statistical differences between in-person and online post-training survey results for two out of the three Knowledge questions and all 11 Attitude questions. Conclusions: This study demonstrates that our OOART was effective in increasing opioid overdose reversal knowledge and reducing OUD stigma. There was no meaningful difference in outcomes between the training modalities. These results support the future expansion of online and in-person OOART to a larger population of medical students.