Effects of particulate matter (PM2.5) on life history traits, oxidative stress, and defensome system in the marine copepod Tigriopus japonicus

Particulate matter (PM2.5) generated in large cities creates new problems in marine ecosystems and may adversely affect its inhabitants. However, the mechanisms underlying the same remain unclear; hence, we investigated the effects of PM2.5 on life history traits (e.g., mortality, development, and fecundity), cellular reactive oxygen species (ROS) levels, antioxidant enzyme (e.g., glutathione peroxidase [GPx], superoxide dismutase [SOD], and catalase [CAT]) activities, and the transcript levels of detoxification-related genes (cytochrome P450s [CYPs]) and antioxidant (glutathione S-transferases [GSTs]) in the copepod Tigriopus japonicus. Among the life history traits, developmental time was the only trait to significantly deviate (P < 0.05) in response to PM2.5 (compared to that in the controls). Significant changes in ROS levels and antioxidant enzymatic activities (P < 0.05) in response to PM2.5, suggested that PM2.5 can induce oxidative stress, leading to adverse effects on the T. japonicus life history. In addition, PM2.5 induced a differential regulation of various CYP and GST genes, particularly CYP307E1, GST-kappa, and GST-sigma were significantly upregulated (P < 0.05), suggesting that these genes likely play crucial roles in detoxification mechanisms and could be useful as reliable biomarkers for PM2.5 toxicity. Overall, the results of this study provide new insights into the potential toxicity of PM2.5.