Organochlorine pesticides (OCPs) impact on the immunological activation pathways of the honey bee (Apis mellifera)

Abstract

Massive mortalities of the honey bee Apis mellifera called Colony Collapse Syndrome (CCD) are registered in the world. These events have been attributed to factors physical, chemical and biological. In addition, honey bee and their products are considered key tools in the evaluation of the health of ecosystems, since are a group of organism are in direct contact with environmental and anthropogenic factors such as pollutants. Pesticides like organochlorines (OCPs) are considered persistent organic pollutants, extremely toxic and dangerous for humans and bees, because can cause neurotoxicity and immunotoxicity, like as mutations, cancer and death. To mitigate the adverse effects of pollutants, vertebrates and invertebrates have detoxification systems conformed by various enzymatic pathways. However, in A. mellifera, the number of genes that involved these enzymes is limited. It has been documented, the suitable immune pathways activation of A. mellifera is essential to combat xenobiotics and pathogens such as viruses, bacteria, and protozoa. This activation starts when Pattern Recognition Receptors (PRRs) detect the Pathogen Associated Molecular Patterns (PAMPs) or Damage Associated Molecular Patterns (DAMPs). Signalling pathways include toll, JAK/STAT, RNAi, Imd, JNK, and melanization including prophenoloxidase (proPO). Few studies have been aimed at assessing the effects of OCPs on A. mellifera. Although pesticides are known to have genotoxic effect on immune system genes like AMPs, abaecin, hymenoptaecin, apisimin, defensin, lysozyme, TOLL, PCE, relish, hopscotch, domeless, NF-kB, spaetzle, cactus, dorsal, basket and proPO. Moreover, pathogenic infection showed alteration in the expression of the genes that code for JNK/bsk, p53, iap-2, caspase, NF-kB, Toll, Tube and Tep-B. In this sense, the identification of key genes alteration of the immune system as a response against pathogens would allow the determination of sensitive biomarkers of OCPs, as well as the evaluation of their impact on A. mellifera and the ecosystem health. Therefore, this review highlights the importance of the immune response of the honey bees A. mellifera, focused in the activation pathways and the genotoxic impact of the OCPs. Keywords: Apis mellifera, organochlorine pesticides (OCPs), genotoxicity, immunotoxicity.