Biological effects of nanomaterials in drosophila melanogaster (diptera, insecta) as in vivo model
- Autores: Mohamed Alaraby Abdalaziz Mohamed
- Directores de la Tesis: Alba Hernández Bonilla (dir. tes.), Ricardo Marcos Dauder (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2016
- Idioma: inglés
- Tribunal Calificador de la Tesis: M. Antonia Velázquez Henar (presid.), Antonio Guzmán Cano (secret.), M. Borràs Suárez (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Genética
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
Abstract Nanomaterials (NMs) are invading most of our life fields and they are used in wide applications. Their physical and chemical properties often differ from those of bulk materials due to their small size. The extremely small size of NMs means that they are much more readily taken up by the human body than larger sized particles. Actually, the possible harmful effects of NMs are mainly evaluated using controlled laboratory tests (in vitro assays) or using living organisms (in vivo assays) to improve our knowledge on possible risks to people and environment.
As an in vivo model Drosophila melanogaster has been used for determining the biological effects of NMs, and its usage has increased considerably over the last years. The validity of Drosophila as in vivo model attributed to its ability to mimic the real events associated with NMs exposure. In addition to, simple, less cost and ethic consideration are important items to select Drosophila as representative model. Herein, in this Thesis we aimed to diagnosis the biological interaction for different types of nanomaterials, that difference in size, composition and shape (cerium, zinc, copper nanoparticles, and cadmium quantum dots) using D. melanogaster.
Our results showed that Drosophila successes to mimic the interaction of the intestinal barrier with the NMs orally administrated. Although the peritrophic membrane (similar to the mucus in the mammalian barrier) showed effective role in restricting NMs internalization, some of them successes to penetrated not only into microvilli and cytoplasm of midgut cells but into hemolymph and hemocytes for all studied NPs. Whereas, both cerium and zinc nanoparticles failed to reduce flies survival, as well as their ionic forms, copper nanoparticles and cadmium quantum dots significantly induced toxic effects. The conserved heat shock proteins in Drosophila showed high sensitivity to all studied NMs. In addition, the antioxidant system and genotoxic related genes of Drosophila showed sensitivity to NPs exposure, mainly to the higher toxic ones as copper and cadmium. These cellular responses were attributed to the ability of the NPs materials or releasing ions. Moreover, the internalization and interaction of NPs during their trip after oral administration was detected via a set of marker genes that were inhibited in associated with copper NPs exposure.
In this Thesis the primarily and fixed genotoxicity of NPs was determined with the comet and SMART assays, respectively. The non-toxic NPs as cerium and zinc failed to increased DNA damage or breaks. Although copper NPs did not elevate DNA breaks levels, DNA breaks were increased with exposure to copper ions. On the contrary cadmium, regardless its forms, successes to increased DNA breaks in a dose-dependent manner. Notably, all the studied NPs were unable to induce mutagenic effects (wing-spot assay). Importantly, Drosophila successes showing the antigenotoxic properties of NPs able to reduce oxidative stress, as occur with cerium NPs.
As an overall all of our results support the validity of Drosophila as sensitive in vivo model to comprehensively evaluate the biological interaction of NPs materials via a wide set of approaches.
