Molecular mechanisms of cellular immune responses in marine invertebrates

• Main Author: Saphörster, Julia
• Other Authors: Rosenstiel, Philip, Leippe, Matthias
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2013
• Subjects: thesis; ddc:500; Transcriptome; bivalves; Mytilus edulis; Lophotrochozoa; evolution; immune system; hemocytes; ROS production; NOX; DUOX; IL-17; Antarctic; The Antarctic; Antarc*; Arctica islandica; Ocean quahog
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-118135; https://macau.uni-kiel.de/receive/diss_mods_00011813; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00004765/Dissertation%20Saphoerster.pdf

Invertebrate and vertebrate organisms alike rely on efficient immune mechanisms to cope with potentially harmful microbes. Immune cells of invertebrates, e.g. hemocytes in bivalves, perform innate but not adaptive immune responses as found in lymphatic cells of jawed vertebrates. Since several genes and principles of innate immunity are highly conserved throughout the animal kingdom, invertebrates are sometimes even regarded as a simplified model of the vertebrate innate immune system. Most invertebrate animals belong to one of the three major bilaterian clades: Deuterostomia, Ecdysozoa or Lophotrochozoa. Whereas research on innate immunity was mainly conducted in the first two groups, information about molecular immune mechanisms in the Lophotrochozoa, including molluscs such as bivalves, is still scarce. In addition, marine, invertebrate filter feeders, such as bivalves, are especially suited to elucidate evolutionary conserved immune responses, since they are constantly in direct contact with the surrounding sea water and, hence, with the microbiota within. Therefore, this project aimed to identify and characterize putative conserved and important proteins and pathways of innate immune responses at molecular level in bivalves, including the ocean quahog, Arctica islandica, the Antarctic bivalve Laternula elliptica and especially the ecologically and economically important blue mussel Mytilus edulis. To provide the molecular basis for subsequent investigations, transcriptome datasets of unstimulated and flagellin-challenged M. edulis hemocytes were generated using massively parallel sequencing techniques (Roche 454). Comparative analysis of putative conserved pathways in the generated and existing M. edulis transcriptome datasets displayed an enrichment of putative immune relevant pathways in hemocytes. Furthermore, deeper insights into the time-dependent mRNA expression pattern of selected receptors, regulators and effectors of potential immune pathways in M. edulis revealed early- (e.g. NF-κB pathway ...