Exploring urban pollution in coastal ecosystems: microfiber-antibiotic interactions and toxicity in cells of a model oyster species

• Grant number: 25/02347-5
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: May 30, 2025
• End date: May 29, 2026
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Renata de Britto Mari
• Grantee: Leticia Fernanda da Silva
• Supervisor: Rafael Trevisan
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil
• Institution abroad: Laboratoire Des Sciences De L'Environnement Marin, France
• Associated to the scholarship: 22/12484-1 - Evaluation of the sublethal effects of plastic microfibers in association with the antibiotic amoxicillin on Crassostrea brasiliana oysters, BP.DR

Abstract

Synthetic fibers comprise the most significant fraction of microplastics polluting our oceans, posing an alarming threat to marine life. Their significant loads in urban wastewater endanger local species and ecosystems but also indicate that synthetic fibers can interact with other harmful contaminants like antibiotics, amplifying the risk to marine organisms. This project will advance our research on assessing and identifying the impacts of textile microfibers and pharmaceuticals on marine invertebrates. We have recently identified the translocation of synthetic fibers into the circulatorysystem (hemolymph) of oysters and their adverse effects on the viability of immune cells(hemocytes). Profiting from the recognized expertise in marine cellular biology at LEMAR, we will use the hemolymph circulatory cells (hemocytes) of an ecotoxicology model oyster, Crassostrea gigas, to investigate the toxicity mechanisms and modes of action of polyester microfibers contaminated with the antibiotic amoxicillin. Following our established protocols for fiber preparation and fortification, we will collect fibers from the effluent of a commercial washingmachine after washing polyester fabrics. These fibers will then be fortified in vitro with amoxicillin to simulate the interactions between textile fibers and urban contaminants. The experimental design will include four treatment groups: a control group, polyester fibers, amoxicillin, and polyester fibers fortified with amoxicillin. We will expose primary cultures of C. gigas hemocytes to these treatments over periods of 1, 3, and 7 days. Following the exposure, we will assess metrics such as cell morphology and viability, general metabolic activity, energy production indexes, production ofreactive oxygen species, antioxidant capacity, and mitochondrial membrane potential. We will alsoevaluate immune responses, including bacterial clearance and phagocytosis rates. Thiscomprehensive in vitro approach will provide novel mechanisms of toxicity related to cellularmetabolism, oxidative stress, and immunology in marine bivalves. It will also provide valuableinsights and innovative techniques for the candidate and expand the research network of our research group, leading to critical findings that enhance our understanding of the threats posed by the intersection of marine and wastewater pollution in coastal ecosystems.