Taming the symbiont for coexistence: a host PGRP neutralizes a bacterial symbiont toxin
Summary In horizontally transmitted mutualisms between marine animals and their bacterial partners, the host environment promotes the initial colonization by specific symbionts that it harvests from the surrounding bacterioplankton. Subsequently, the host must develop long‐term tolerance to immunoge...
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Published in | Environmental microbiology Vol. 12; no. 8; pp. 2190 - 2203 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Publishing Ltd
01.08.2010
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Subjects | |
Online Access | Get full text |
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Summary: | Summary
In horizontally transmitted mutualisms between marine animals and their bacterial partners, the host environment promotes the initial colonization by specific symbionts that it harvests from the surrounding bacterioplankton. Subsequently, the host must develop long‐term tolerance to immunogenic bacterial molecules, such as peptidoglycan and lipopolysaccaride derivatives. We describe the characterization of the activity of a host peptidoglycan recognition protein (EsPGRP2) during establishment of the symbiosis between the squid Euprymna scolopes and its luminous bacterial symbiont Vibrio fischeri. Using confocal immunocytochemistry, we localized EsPGRP2 to all epithelial surfaces of the animal, and determined that it is exported in association with mucus shedding. Most notably, EsPGRP2 was released by the crypt epithelia into the extracellular spaces housing the symbionts. This translocation occurred only after the symbionts had triggered host morphogenesis, a process that is induced by exposure to the peptidoglycan monomer tracheal cytotoxin (TCT), a bacterial ‘toxin’ that is constitutively exported by V. fischeri. Enzymatic analyses demonstrated that, like many described PGRPs, EsPGRP2 has a TCT‐degrading amidase activity. The timing of EsPGRP2 export into the crypts provides evidence that the host does not export this protein until after TCT induces morphogenesis, and thereafter EsPGRP2 is constantly present in the crypts ameliorating the effects of V. fischeri TCT. |
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Bibliography: | istex:3F7CA3DD9392B1B2EE923BAD542A23F490DD77D9 ArticleID:EMI2121 ark:/67375/WNG-30T5PRW6-4 Present address: Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Current address: Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA |
ISSN: | 1462-2912 1462-2920 |
DOI: | 10.1111/j.1462-2920.2009.02121.x |