title: Differential expression of ribosomal protein gene, gonadotrophin releasing hormone gene and Balbiani ring protein gene in silver nanoparticles exposed Chironomus riparius.
abstract: The eco- and genotoxicity of silver nanoparticles (AgNPs) was investigated in the fourth instar larvae of the aquatic midge, Chironomus riparius. AgNPs did not have acute toxicity in C. riparius, but did exhibited chronic toxicity on development (pupation and emergence failure) and reproduction. Genotoxicity also occurred in AgNPs exposed C. riparius. Differential Display PCR (DD-PCR), based on the Annealing Control Primer (ACP) technique, was conducted to investigate the underlying toxic mechanism, which identified altered gene expression in C. riparius after treatment with AgNPs. The possible toxicity mechanism of AgNPs in C. riparius involves the down regulation of the ribosomal protein gene (CrL15) affecting the ribosomal assembly and consequently, protein synthesis. Up regulation of the gonadotrophin releasing hormone gene (CrGnRH1) might lead to the activation of gonadotrophin releasing hormone mediated signal transduction pathways and reproductive failure. Up regulation of the Balbiani ring protein gene (CrBR2.2) may be an indication of the organism's protection mechanism against the AgNPs. The overall results suggest that the toxicity of AgNPs towards aquatic organisms should be thoroughly investigated to allow for their safe use, as they seem to exhibit important toxicity towards C. riparius.
authors.affiliation: School of Environmental Engineering and Graduate School of Urban Sciences, University of Seoul, Seoul, Republic of Korea.
authors.forename: Prakash M Gopalakrishnan
authors.initials: PM
authors.lastname: Nair
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Park
authors.forename: Si-Won
authors.initials: SW
authors.lastname: Lee
authors.forename: Jinhee
authors.initials: J
authors.lastname: Choi
mesh_terms: D000818:Animals; D002683:Chironomidae / Q000378:metabolism*; D059045:Chromosomal Puffs / Q000235:genetics / Q000378:metabolism*; D020552:Comet Assay; D005786:Gene Expression Regulation / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity*; D009152:Mutagenicity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D012269:Ribosomal Proteins / Q000378:metabolism*; D012834:Silver / Q000633:toxicity*
chemical_list: D012269:Ribosomal Proteins; D007987:Gonadotropin-Releasing Hormone; D012834:Silver