FIGURE WO-7. The “winnowing.”.

FIGURE WO-7The “winnowing.”

This model depicts the progression of light-organ colonization as a series of steps, each more specific for symbiosis-competent Vibrio fischeri. (a) In response to gram-positive and gram-negative bacteria (alive or dead) the bacterial peptidoglycan signal causes the cells of the ciliated surface epithelium to secrete mucus. (b) Only viable gram-negative bacteria form dense aggregations. (c) Motile or non-motile V. fischeri out-compete other gram-negative bacteria for space and become dominant in the aggregations. (d) Viable and motile V. fischeri are the only bacteria that are able to migrate through the pores and into the ducts to colonize host tissue. (e) Following successful colonization, symbiotic bacterial cells become non-motile and induce host epithelial cell swelling. Only bioluminescent V. fischeri will sustain long-term colonization of the crypt epithelium.

SOURCE: Reprinted from Nyholm and McFall-Ngai (2004) with permission from Macmillan Publishers Ltd. Copyright 2004.

From: Workshop Overview

Cover of Microbial Evolution and Co-Adaptation
Microbial Evolution and Co-Adaptation: A Tribute to the Life and Scientific Legacies of Joshua Lederberg: Workshop Summary.
Institute of Medicine (US) Forum on Microbial Threats.
Washington (DC): National Academies Press (US); 2009.
Copyright © 2009, National Academy of Sciences.

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