Project description:The contamination of marine ecosystems with microplastics, such as the polymer polyethylene, a commonly used component of single-use packaging, is of global concern. Although it has been suggested that biodegradable polymers, such as polylactic acid, may be used to replace some polyethylene packaging, little is known about their effects on marine organisms. Blue mussels, Mytilus edulis, have become a “model organism” for investigating the effects of microplastics in marine ecosystems. We show here that repeated exposure, over a period of 52 days in an outdoor mesocosm setting, of M. edulis to polyethylene microplastics reduced the number of byssal threads produced and the attachment strength (tenacity) by ~50%. Exposure to either type of microplastic altered the haemolymph proteome and, although a conserved response to microplastic exposure was observed, overall polyethylene resulted in more changes to protein abundances than polylactic acid. Many of the proteins affected are involved in vital biological processes, such as immune- and stress- regulation, metabolism and cellular and structural development. Our study highlights the utility of mass spectrometry-based proteomics to assess the health of key marine organisms and identifies the potential mechanisms by which microplastics, both conventional and biodegradable, could affect their ability to form and maintain reefs.
Project description:Humans and animals encounter a summation of exposures during their lifetime (the exposome). In recent years, the scope of the exposome has begun to include microplastics. Microplastics (MPs) have increasingly been found in locations where there could be an interaction with Salmonella enterica Typhimurium, one of the commonly isolated serovars from processed chicken. In this study, the microbiota response to a 24-hour co-exposure to Salmonella enterica Typhimurium and/or low-density polyethylene (PE) microplastics in an in vitro broiler cecal model was determined using 16S rRNA amplicon sequencing (Illumina) and untargeted metabolomics. Community sequencing results indicated that PE fiber with and without S. Typhimurium yielded a lower Firmicutes/Bacteroides ratio compared to other treatment groups, which is associated with poor gut health, and overall had greater changes to the cecal microbial community composition. However, changes in the total metabolome were primarily driven by the presence of S. Typhimurium. Additionally, the co-exposure to PE Fiber and S. Typhimurium caused greater cecal microbial community and metabolome changes than either exposure alone. Our results indicate that polymer shape is an important factor in effects resulting from exposure. It also demonstrates that microplastic-pathogen interactions cause metabolic alterations to the chicken cecal microbiome in an in vitro chicken cecal model.
Project description:Microplastics are defined as plastics ranging in size from 0.1μm to 5mm. Currently, research is being conducted across various fields to examine the effects of microplastics. Some studies demonstrated negative impacts on cells and mice. However, there is a lack of research on the effects by long-term exposure to microplastics. Most of the papers evaluated cytotoxicity with period of less than 2 months. Therefore, in this study, we investigated the potential issues that may arise from prolonged exposure through food mixed with Polyethylene microplastic (PE-MP) for over a year. We divided our study into short, mid, and long-term periods to assess cytotoxicity through Glucose tolerance test, Insulin tolerance test, analysis of insulin and c-peptide levels, hanging, grip, treadmill, Y-maze and open field tests, Respiratory Exchange Ratio, Energy Expenditure, Activity, and body composition. Through this, we comprehensively examined potential issues related to mouse behavior, muscle, metabolism and other factors. After dissection, RNA sequencing was carried out to investigate the effects on genes. For further verification, RT-qPCR was conducted. To summarize, our study provides evidence suggesting that treatment of microplastics for a short term has adverse effects, but with prolonged exposure, their effects tend to diminish.