Effects of Polystyrene Microplastics on the Metabolic Level of Pseudomonas Aeruginosa

Abstract

The pollution of microplastics (MPs) has become increasingly serious in recent years, and MPs have been defined as one of the several key new pollutants in the environment during the “14th Five-Year Plan” period. From the perspective of molecular function, the metabolic changes in Pseudomonas aeruginosa under PS-MPs exposure were studied. Based on non-targeted metabolomics, a total of 64 differential metabolites were screened out under positive ion mode and 44 under negative ion mode. The content of bacterial metabolites changed significantly, mainly involving lipids, nucleotides, amino acids, and organic acids, etc. Severe intracellular oxidative damage resulted in decreased expression of lipid molecules and nucleotide-related metabolites. The down-regulation of amino acid metabolites, such as L-Glutamic and L-Proline, indicated disorders in cellular energy metabolism and inability to synthesize proteins to counteract oxidation. The interference of PS-MPs on organic acid metabolism mainly reflected on the inhibition of pyruvate and citrate, so the cells cannot normally participate in the energy cycle. Combined with KEGG analysis, PS-MPs mainly caused changes in ABC transporters, Aminoacyl-tRNA biosynthesis, Purine metabolism, Glycerophospholipid metabolism, TCA cycle and other pathways. Most of the differential metabolites enriched in these pathways were down-regulated, demonstrating that PS-MPs inhibited the expression of metabolic pathways to disrupt the ability of cells to synthesize proteins, DNA, and RNA. This disruption would affect cell proliferation and information transduction, thus reducing energy circulation and inhibiting cell growth.

Keywords: Pseudomonas aeruginosa, Polystyrene microplastics (PS-MPs), Metabolites, KEGG, Metabolic pathways