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Chromium exhibits adverse effects at environmental relevant concentrations in chronic toxicity assay system of nematode Caenorhabditis elegans
Quili Wu, Yangyang Qu, Xing Li, Dayong Wang ⇑
Key Laboratory of Environmental MedicineEngineering in Ministry of Education, Department of Biochemistry and Molecular Biology, Medical School of Southeast University, Nanjing 210009, China
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Here we investigated whether the assay system (10-d) in Caenorhabditis elegans can be used to evaluate chronic toxicity of chromium (Cr(VI)) at environmental relevant concentrations ranging from 5.2 lg LÀ1 to260 lg LÀ1. The results indicated that lethality, locomotion behavior as revealed by head thrash, body bend, and forward turn, metabolism as revealed by pumping rate and mean defecation cycle length, intestinal autoﬂuorescence, and ROS production were severely altered in Cr chronically exposed nematodes at environmental relevant concentrations. The most surprising observations were that headthrash, body bend, intestinal autoﬂuorescence, and ROS production in 13 lg LÀ1 Cr exposed nematodes were signiﬁcantly inﬂuenced. The observed adverse effects of Cr on survival, locomotion behavior, and metabolism were largely due to forming severe intestinal autoﬂuorescence and ROS production. Therefore, our ﬁndings demonstrate the usefulness of chronic toxicity assay system in C. elegans in evaluatingthe chronic toxicity of toxicants at environmental relevant concentrations. Ó 2012 Elsevier Ltd. All rights reserved.
Article history: Received 21 October 2011 Received in revised form 21 December 2011 Accepted 20 January 2012 Available online 14 February 2012 Keywords: Chromium exposure Chronic toxicity Environmental relevant concentration Caenorhabditis elegans
1. Introduction Chromium(Cr) and its compounds have been recognized as having potential severe adverse effects on health for more than 180 years. Because Cr is widely used in the chemical industry for different applications such as pigments, metal plating, or leather tanning and in chemical production, different species of Cr can be released into the environment (Unceta et al., 2010). Moreover, Cr in contaminated water andsoil has hazardous effects on ﬁsh, wildlife, and invertebrates (Eisler, 1986; Lushchak et al., 2009). Although water is important for survival and existence of life, wastewater from the urban and the industrial workplaces usually contain toxic metals including Cr (Salf et al., 2005). Besides the fact that industrial efﬂuents are the most potential water pollutants, sewage water may also containsigniﬁcant amount of heavy metals such as Cr (Latif et al., 2008). It was reported that 0.004– 5.62 mg LÀ1 Cr existed in irrigation water samples from Korangi industrial area in Pakistan (Salf et al., 2005). Chromium contents in some of the tubewell water samples in Rawalpindi area were observed above the maximum permissible samples (Latif et al., 2008). Especially, it has been found that thenaturally occurring Cr(VI) in ground and surface waters at values exceeding the World Health Organization limit for drinking water of 50 lg LÀ1 (Velma et al., 2009). Therefore, it is very important to evaluate the chronic toxicity of Cr at environmental relevant concentrations.
⇑ Corresponding author. Tel.: +86 25 83272510.
E-mail address: firstname.lastname@example.org (D. Wang). 0045-6535/$ - see front matterÓ 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2012.01.035
Caenorhabditis elegans, a free living nematode that lives mainly in the liquid phase of soils, is considered as an ideal model animal for the study of environmental evaluation and toxicity (Leung et al., 2008). C. elegans is now widely used in ecotoxicological studies utilizing various exposure media, including...