Evaluating the potential toxicity of ampicillin using Drosophila melanogaster as a model organism

Antibiotic resistance is an indispensable threat facing in the present era. However, the studies on long term and trans-generational effects of using drugs or antibiotics on living organisms are scarce. Emphasizing the necessity to address such problems, this study investigated the potential effects of antibiotic, ampicillin (AMP) stress on the physiology of <i>Drosophila melanogaster</i> across multiple generations with mechanistic details. We evaluated the larval feeding behavior, fertility, cell viability in ovary and testis, longevity, expression of methylation-related genes (<i>dDnmt2</i> and <i>dMBD2/3</i>), and antimicrobial peptide production. Larvae exposed to AMP exhibited increased mouth hook movement, indicating altered behaviour. AMP stress significantly reduced fertility across generations, with eclosion counts decreasing notably in F₃ and F₄ generations compared to controls. Moreover, AMP-treated flies showed decreased cell viability in ovary and testis, leading to impaired reproductive function. AMP exposure shortened the mean lifespan of flies and upregulated the expression of apoptosis-related gene <i>p53</i> in females. However, there was no significant difference in <i>p53</i> expression in males. Additionally, AMP stress caused a significant decrease in <i>Drosomycin</i> expression in treated males, while no significant changes were observed in <i>Drosocin</i> and <i>Metchnikowin</i>. In treated females, <i>Drosocin</i> and <i>Drosomycin</i> expression increased significantly, whereas the increase in <i>Metchnikowin</i> was not significant. The study also revealed downregulation of methylation-related genes (<i>dDnmt2</i> and <i>dMBD2/3</i>) in AMP-treated female flies which was normalised in the rescue flies suggesting disrupted epigenetic mechanisms. Overall, the findings highlighted the importance of evaluating the trans-generational impacts of AMP stress on <i>Drosophila</i> physiology and gene expression, particularly in reproductive function and epigenetic regulation. The study of the impact of widely used antibiotic, AMP on model organism, <i>Drosophila</i> (model organism known for its genetic similarity to human), will help in predicting potential impacts on higher organisms and human. The finding would ultimately promote proper use of antibiotics and use of alternative medicine.