Identification of a glutathione S-transferase gene of Physarum polycephalum as a biomarker for nanosized TiO exposure under dark conditions.

UNLABELLED

In this study, a glutathione S-transferase gene (gst) from sensitive Physarum polycephalum was selected for its ability to detect nanosized TiO (nTiO ) exposure under dark conditions. The concentration of nTiO (25, 40 and 60 nm) for subsequent assays was first determined (5-18 mg ml ) and total GST enzyme activity of P. polycephalum was confirmed to be increased 6-44 fold in groups treated with nTiO . Second, an RNA-seq study was performed to identify candidate gst genes before isolation of an optimum gst gene of P. polycephalum (Ppgst), which encoded 223 amino acids. Third, the transcriptional level of the Ppgst gene was further confirmed to be positively correlated with nTiO exposure within the concentration range of (5-15 mg ml ) by qPCR. In conclusion, these results indicated that the transcriptional level of Ppgst can reflect nTiO exposure, suggesting that it may be employed as a new biomarker for nTiO pollution under dark conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study identifies a new gst gene for indicating nanosized TiO under dark conditions and provides a new option for detection of nanosized TiO pollution under dark conditions.