C₆₀exposure induced tissue damage and gene expression alterations in the earthwormLumbricus rubellus

Abstract

Effects of C₆₀ exposure (0, 15 or 154 mg/kg soil) on the earthworm Lumbricus rubellus were assessed at the tissue and molecular level, in two experiments. In the first experiment, earthworms were exposed for four weeks, and in the second lifelong. In both experiments, gene expression of heat shock protein 70 (HSP70) decreased. For catalase and glutathione-S-transferase (GST), no significant trends in gene expression or enzyme activity were observed. Gene expression of coelomic cytolytic factor-1 (CCF-1) did not alter in earthworms exposed for four weeks, but was significantly down-regulated in the lifelong exposure. Histology of earthworms exposed to C₆₀ in both experiments showed a damaged cuticle, with underlying pathologies of epidermis and muscles, as well as effects on the gut barrier. However, tissue repair was also observed in these earthworms. Overall, these data show that sub-lethal C₆₀ exposure to earthworms via the soil affects gene expression and causes tissue pathologies.

Analysis of Eisenia fetida earthworm responses to sub-lethal C60 nanoparticle exposure using 1H-NMR based metabolomics

“…van der Ploeg et al (2013) also observed adaptive responses in L. rubellus after C 60 nanoparticle exposure. After 4 weeks, the gut epithelial tissue was damaged, however after lifelong exposure the damage to the gut epithelial tissue was less severe, suggesting activation of tissue repair mechanisms (van der Ploeg et al, 2013). Similar adaptive responses of earthworms to xenobiotics have been observed in other studies as well (Corp and Morgan, 1991;Maity et al, 2008;Spurgeon and Hopkin, 1999).…”

“…Toxic responses were observed faster in soil tests as compared to contact tests suggesting that the method of exposure is important in dictating the metabolic response. Soil studies also revealed that after 14 days of exposure, the earthworms potentially exhibited tolerance to C 60 nanoparticles, which revealed adaptive response at the molecular-level complementing the histological adaptive response reported by van der Ploeg et al (2013) in L. rubellus earthworms. The amino acids leucine, valine, isoleucine and phenylalanine, the nucleoside inosine and the sugars glucose and maltose emerged as potential bioindicators of exposure to C 60 nanoparticles and should be analyzed in a targeted manner in future studies to determine their concentration-dependent fluctuations over a wide range of sub-lethal C 60 nanoparticle exposure concentrations.…”

“…In addition, exposure of C 60 nanoparticles to L. rubellus earthworms resulted in a down-regulation in the gene expression of HSP70 which may indicate an increase in global protein production (van der Ploeg et al, 2013). Therefore, similar increases in the production of proteins such as enzymes in E. fetida earthworms can explain the observed decreases in these amino acids after C 60 nanoparticle exposure.…”

“…3 and 4). Exposure of C 60 nanoparticles to L. rubellus earthworms induced tissue damage evidenced by damaged cuticles and underlying pathology in the rest of the ectoderm (van der Ploeg et al, 2013). Similar tissue damages may have been induced in E. fetida earthworms leading to the increased production of HEFS to aid membrane stabilization.…”

“…In addition, we also identified bioindicators of C 60 nanoparticle exposure and to delineate the MOA. Finally, we also tested multiple days of exposure to determine if E. fetida developed an adaptation to C 60 nanoparticle exposure as was observed by van der Ploeg et al (2013) in their exposure of C 60 nanoparticles to Lumbricus rubellus earthworms. This study will aid in understanding the C 60 nanoparticles toxicity to earthworms and also help the continued progression of NMR-based metabolomics as a reliable, rapid and routine ecotoxicity tool in assessing contaminant toxicity.…”