The Tetrahymena Paradigm: Genetic Insights and Ecotoxicity Assessment

Abstract

Tetrahymena, a ciliated protozoan, thrives in freshwater habitats across diverse climates. Its importance as a genetic model organism lies in its cellular complexity, with cells comparable to human cells and a genome size between yeast and human. Tetrahymena’s germline genome undergoes unique chromosome breakage and DNA elimination, shedding light on genome rearrangement mechanisms. In 2020, the macronuclear genome was fully sequenced, offering improved insights into chromosome structure and gene models. Tetrahymena’s molecular tools enable gene characterization, knockouts, and overexpression. Beyond genetics, Tetrahymena serves as an ecotoxicity model, particularly Tetrahymena pyriformis. Changes in its morphology, food vacuole formation, and contractile vacuole response serve as toxicity indicators. Tetrahymena’s unique nuclear dimorphism (micronucleus and macronucleus) adds depth to ecotoxicological research. Additionally, Tetrahymena’s behavioral endpoints, including chemotaxis, phagocytosis, and motility, offer sensitive toxicity markers. Researchers have developed a T-maze toxotactic assay, a quick tool for studying Tetrahymena’s behavioral responses to different chemicals. Tetrahymena’s phagocytosis and motility are influenced by exposure to toxicants, reflecting changes in ion channels. Tetrahymena’s rapid movement makes it ideal for studying motility alterations caused by toxic substances. AI-driven tools enhance Tetrahymena behavior studies, allowing for behavior classification, feature extraction, and predictive modeling. This interdisciplinary approach aids in understanding Tetrahymena’s intricate behaviors, offering potential applications in gene discovery and pharmacological interventions. In conclusion, Tetrahymena stands as an invaluable model organism for genetic and ecotoxicological research. Its advantages, including genetic tractability and behavioral sensitivity, contribute to our understanding of fundamental biological processes and chemical safety assessment, with AI playing a growing role in advancing this field.