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Immune responses of the insect Manduca sexta towards the bacterium Photorhabdus luminescens

The Gram-negative bacterium Photorhabdus luminescens is a pathogen of insects. It is able to secrete a variety of toxins and effectors against its host in order to escape its immune defences. The model insect Manduca sexta is able to mount a variety of humoral and cellular responses against pathogen attack. Ultimately these prove ineffective against P. luminescens. The pre-treatment of M. sexta with Escherichia coli provides protection against the pathogenesis of P. luminescens. Here, I use RNA interference and Fluorescence-assisted cell sorting techniques to investigate interactions between pathogen and host to further elucidate the roles of various host factors in mounting the immune response. I also investigate the nutrient requirements of the bacteria for pathogenesis. I show data that peptidoglycan recognition protein (PGRP) is essential for the up-regulation of antimicrobial peptides, an important immune defence. I also show that P. luminescens has a requirement for two types of iron during pathogenesis of M. sexta. And lastly I show that P. luminescens is able to avoid phagocytosis, another important immune defence.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:501624
Date January 2008
CreatorsMillichap, Peter
ContributorsReynolds, Stuart
PublisherUniversity of Bath
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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