Quorum Sensing

Chapter 23

A Culture-Dependent Method for the Identification

of Quorum Quenching Enzymes of Microbial Origin

Kaihao Tang and Xiao-Hua Zhang

Abstract

Although it has been more than a decade since the first discovery of AHL lactonase AiiA inBacillussp.
240B1, we are only beginning to understand the diversity of quorum quenching (QQ) enzymes. Most of
the previously identified QQ enzymes are derived from nonmarine microorganisms. A novel marine-derived
secretory AHL lactonase, MomL, was found inMuricauda oleariain our previous work and represents a
novel type of AHL lactonase widespread in the ocean. Herein, we describe a culture-dependent method for
the identification of microbial QQ enzymes, especially the high-throughput method for screening QQ
bacteria from cultivable bacterial strains. This method should be capable of efficiently identifying QQ
enzymes from various microbial origins. The discovery of more QQ enzymes will help us to understand
their ecological roles and may provide potential as therapeutic agents.

Key wordsQuorum sensing, Quorum quenching, QQ enzyme, Lactonase,Agrobacterium tumefa-

ciensA136 (pCF218)(pCF372)

1 Introduction

Quorum sensing (QS) refers to a population-dependent intercellu-

lar communication in microorganisms, involved in important beha-

viors such as biofilm formation [1], bioluminescence [2, 3], and

secretion of virulence factors [4]. Gram-negative bacteria com-

monly useN-acyl homoserine lactones (AHLs) as QS signaling

molecules and AHL-dependent QS is related with virulence in

many bacterial pathogens [5, 6]. In the first few decades, research-

ers focused mostly on the study of various QS circuits, and it was

not until 2000 that the AHL-degrading ability was firstly discov-

ered inBacillussp. 240B1 [7]. Since then, a number of AHL-

degrading enzymes have been found in mammals, plants, fungi,

archaea, and bacteria [4, 5]. This enzymatic degradation of QS

signaling molecules is termed quorum quenching (QQ). QQ has

been recognized as a promising antivirulence therapy because it can

attenuate virulence without killing the bacteria, and thereby

Livia Leoni and Giordano Rampioni (eds.),Quorum Sensing: Methods and Protocols, Methods in Molecular Biology,
vol. 1673,https://doi.org/10.1007/978-1-4939-7309-5_23,©Springer Science+Business Media LLC 2018

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