Project description:Cadmium sulphide quantum dots (CdS QDs) are widely used in novel equipment. The relevance of the research lies in the need to develop risk assessments for nanomaterials (ENMs), using baker's yeast as model system. A whole-genome microarray experiment, performed on Saccharomyces cerevisiae (BY4742), showed how genes were regulated in response to CdS QDs.
Project description:In this study we investigate the transcriptomic response of Escherichia coli to CdTe-2.4 and benign CdSe-2.4 quantum dots, each with and without illumination to elucidate the phototherapeutic effect of CdTe-2.4. Our analysis sought to separate the transcriptomic responses of E. coli to the presence of superoxide and the presence of cadmium chalcogenide nanoparticles. We found eight genes to be consistently differentially expressed as a response to superoxide generation, and these genes demonstrate a consistent association with the DNA damage response and deactivation of iron-sulfur clusters, characteristic of a superoxide response. We found eighteen genes associated the presence of cadmium-based quantum dots, in isolation from the superoxide effect. In further analysis of these genes, we performed both amino acid supplementation and gene knockout experiments, identifying the importance of leucyl-tRNA downregulation as a cadmium-based QD response, as well as reinforcing the relationship between CdTe-2.4 stress and iron-sulfur clusters through the gene tusA. This study demonstrates the transcriptomic response of E. coli to CdTe-2.4 and CdSe-2.4 quantum dots and parses the different effects of superoxide versus material effects on the bacteria. Our findings may provide useful information towards the development of quantum dot-based antibacterial therapy in the future.
Project description:Waterborne exposure of adult zebrafish to silver nanoparticles and ionic silver results in silver accumulation and effects at cellular and molecular levels
Project description:Few works have addressed the effects provoked by the exposure to cadmium containing nanoparticles (NPs) on adult zebrafish (Danio rerio). We studied the effects of CdS NPs (5 nm) or ionic cadmium (10 µg Cd/L) after 3 and 21 d of exposure and at 6 months post-exposure (mpe). Acute toxicity was recorded after exposure to both forms of cadmium. Significant cadmium accumulation was measured in the whole fish after both treatments and autometallography showed a higher accumulation of metal in the intestine than that in the liver. Histopathological alterations, such as inflammation in gills and vacuolization in the liver, were detected after the exposure to both cadmium forms and, in a lower extent, at 6 mpe. X-ray analysis proved the presence of CdS NPs in these organs. The hepatic transcriptome analysis revealed that gene ontology terms such as “immune response” or “actin binding” were over-represented after 21 d of exposure to ionic cadmium respect to CdS NPs treatment. Exposure to CdS NPs caused a significant effect on pathways involved in the immune response and oxidative stress, while the exposure to ionic cadmium affected significantly pathways involved in DNA damage and repair and in the energetic metabolism. Oxidative damage to liver proteins was detected after the exposure to ionic cadmium, while a stronger destabilization of the hepatocyte lysosomal membrane was recorded under exposure to CdS NPs. In summary, although ionic cadmium provoked stronger effects than CdS NPs, both cadmium forms exerted an array of lethal and sublethal effects to zebrafish.
