Induced nitric oxide synthesis in the gut of Manduca sexta protects against oral infection by the bacterial pathogen Photorhabdus luminescens

I Eleftherianos, G Felföldi, R H ffrench-Constant, Stuart E Reynolds

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Injecting the insect pathogenic bacterium Photorhabdus luminescens into the blood system of the model lepidopteran insect Manduca sexta induces nitric oxide synthase (NOS) expression in the fat body and blood cells (haemocytes), whereas following oral ingestion of bacteria NOS expression is limited to the gut. We used RNA interference to knock-down expression of NOS throughout the insect. Preventing NOS induction in this way adversely affected the survival of orally infected insects and caused a significant increase in the number of bacteria crossing into the haemolymph. By contrast, knock-down of NOS had no effect on the mortality rate of insects infected with P. luminescens by injection. Pharmacological inhibition of NOS decreased both nitric oxide (NO) levels in the gut wall and survival of orally infected insects, whereas elevation of gut wall NO using an NO donor increased survival of NOS silenced caterpillars. Together, our results imply that induced synthesis of NO is important in mediating insect immune defence against the pathogen by inhibiting transfer of bacteria across the gut wall.
Original languageEnglish
Pages (from-to)507-516
Number of pages10
JournalInsect Molecular Biology
Volume18
Issue number4
DOIs
Publication statusPublished - 2009

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Photorhabdus
Photorhabdus luminescens
Manduca
Manduca sexta
nitric oxide synthase
Bacterial Infections
Nitric Oxide Synthase
nitric oxide
Insects
mouth
Nitric Oxide
digestive system
insects
synthesis
pathogens
infection
Bacteria
bacteria
Hemocytes
Fat Body

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Induced nitric oxide synthesis in the gut of Manduca sexta protects against oral infection by the bacterial pathogen Photorhabdus luminescens. / Eleftherianos, I; Felföldi, G; ffrench-Constant, R H; Reynolds, Stuart E.

In: Insect Molecular Biology, Vol. 18, No. 4, 2009, p. 507-516.

Research output: Contribution to journalArticle

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