Biology Reference
In-Depth Information
5
Detection and Inhibition of Bacterial Cell-Cell
Communication
Scott A. Rice, Diane McDougald, Michael Givskov, and Staffan
Kjelleberg
Summary
Bacteria communicate with other members of their community through the secretion
and perception of small chemical cues or signals. The recognition of a signal normally
leads to the expression of a large suite of genes, which in some bacteria are involved
in the regulation of virulence factors, and as a result, these signaling compounds are
key regulatory factors in many disease processes. Thus, it is of interest when studying
pathogens to understand the mechanisms used to control the expression of virulence genes
so that strategies might be devised for the control of those pathogens. Clearly, the ability
to interfere with this process of signaling represents a novel approach for the treatment
of bacterial infections. There is a broad range of compounds that bacteria can use for
signaling purposes, including fatty acids, peptides, N -acylated homoserine lactones, and
the signals collectively called autoinducer 2 (AI-2). This chapter will focus on the latter
two signaling systems as they are present in a range of medically relevant bacteria, and
here we describe assays for determining whether an organism produces a particular signal
and assays that can be used to identify inhibitors of the signaling cascade. Lastly, the
signal detection and inhibition assays will be directly linked to the expression of virulence
factors of specific pathogens.
Key Words: Quorum sensing; cell-cell signaling; acylated homoserine lactone;
autoinducer 2; virulence factor expression; global regulation; inhibitors.
1. Introduction
It is now recognized that bacteria regulate high-density phenotypes, such as
biofilm formation, and phenotypes that are important for a number of pathogenic
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