Towards early-warning gene signature of Chlamydomonas reinhardtii exposed to Hg-containing complex media

Abstract

The potential of using gene expression signature as a biomarker of toxicants exposure was explored in the microalga Chlamydomonas reinhardtii exposed 2 h to mercury (Hg) as inorganic mercury (IHg) and methyl mercury (MeHg) in presence of copper (Cu) and Suwannee River Humic Acid (SRHA). Total cellular Hg (THg = IHg + MeHg) decreased in presence of SRHA for 0.7 nM IHg and 0.4 nM MeHg, but increased for 70 nM IHg exposure. In mixtures of IHg + MeHg and (IHg or MeHg) + Cu, SRHA decreased THg uptake, except for 0.7 nM IHg + 0.4 nM MeHg which was unchanged (p-value > 0.05). In the absence of SRHA, 0.5 mu M Cu strongly decreased intracellular THg concentration for 70 nM IHg, while it had no effect for 0.7 nM IHg and 0.4 nM MeHg. The expression of single transcripts was not correlated with measured THg uptake, but a subset of 60 transcripts showed signatures specific to the exposed metal(s) and was congruent with exposure concentration. Notably, the range of fold change values of this subset correlated with THg bioaccumulation with a two-slope pattern in line with [THg](intra)/[THg](med) ratios. Gene expression signature seems a promising approach to complement chemical analyses to assess bioavailability of toxicants in presence of other metals and organic matter.

Keywords

Copper; Dissolved organic matter; Microalgae; Uptake; Transcriptomics

Published in

Aquatic Toxicology
2019, Volume: 214, article number: 105259
Publisher: ELSEVIER

SLU Authors

• Skyllberg, Ulf

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG3 Good health and well-being
SDG6 Clean water and sanitation


UKÄ Subject classification

Environmental Management


Publication identifier

DOI: https://doi.org/10.1016/j.aquatox.2019.105259

Permanent link to this page (URI)

https://res.slu.se/id/publ/101980