Dataset Information

Novel N-Acyl Homoserine Lactone-Degrading Bacteria Isolated From Penicillin-Contaminated Environments and Their Quorum-Quenching Activities.

ABSTRACT: N-Acyl homoserine lactones (AHLs) are signaling molecules used in the quorum sensing (QS) of Gram-negative bacteria. Some bacteria interfere with the QS system using AHL-inactivating enzymes, commonly known as quorum-quenching (QQ) enzymes. We have recently isolated a new QQ bacterium showing high resistance to multiple ?-lactam antibiotics, and its QQ enzyme (MacQ) confers ?-lactam antibiotic resistance and exhibits QQ activities. This observation suggests the possibility of isolating novel QQ bacteria from ?-lactam antibiotic-resistant bacteria. In this direction, we attempted to isolate penicillin G (PENG)-resistant bacteria from penicillin-contaminated river sediments and activated sludge treating penicillin-containing wastewater and characterize their QQ activities. Of 19 PENG-resistant isolates, six isolates showed high QQ activity toward a broad range of AHLs, including AHLs with 3-oxo substituents. Five of the six AHL-degraders showed AHL-acylase activity and hydrolyzed the amide bond of AHLs, whereas the remaining one strain did not show AHL-acylase activity, suggesting that this isolate may likely possess alternative degradation mechanism such as AHL-lactonase activity hydrolyzing the lactone ring of AHLs. The 16S rRNA gene sequence analysis results categorized these six AHL-degrading isolates into at least five genera, namely, Sphingomonas (Alphaproteobacteria), Diaphorobacter (Betaproteobacteria), Acidovorax (Betaproteobacteria), Stenotrophomonas (Gammaproteobacteria), and Mycobacterium (Actinobacteria); of these, Mycobacterium sp. M1 has never been known as QQ bacteria. Moreover, multiple ?-lactam antibiotics showed high minimum inhibitory concentrations (MICs) when tested against all of isolates. These results strongly demonstrate that a wide variety of ?-lactam antibiotic-resistant bacteria possess QQ activities. Although the genetic and enzymatic elements are yet unclear, this study may infer the functional and evolutionary correlation between ?-lactam antibiotic resistance and QQ activities.

SUBMITTER: Kusada H

PROVIDER: S-EPMC6426785 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Novel <i>N</i>-Acyl Homoserine Lactone-Degrading Bacteria Isolated From Penicillin-Contaminated Environments and Their Quorum-Quenching Activities.

Kusada Hiroyuki H Zhang Yu Y Tamaki Hideyuki H Kimura Nobutada N Kamagata Yoichi Y

Frontiers in microbiology 20190314

<i>N</i>-Acyl homoserine lactones (AHLs) are signaling molecules used in the quorum sensing (QS) of Gram-negative bacteria. Some bacteria interfere with the QS system using AHL-inactivating enzymes, commonly known as quorum-quenching (QQ) enzymes. We have recently isolated a new QQ bacterium showing high resistance to multiple β-lactam antibiotics, and its QQ enzyme (MacQ) confers β-lactam antibiotic resistance and exhibits QQ activities. This observation suggests the possibility of isolating no ...[more]

PMID: 30923518

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Project description:UnlabelledQuorum sensing, the bacterial cell-cell communication by small molecules, controls important processes such as infection and biofilm formation. Therefore, it is a promising target with several therapeutic and technical applications besides its significant ecological relevance. Enzymes inactivating N-acyl-l-homoserine lactones, the most common class of communication molecules among Gram-negative proteobacteria, mainly belong to the groups of quorum-quenching lactonases or quorum-quenching acylases. However, identification, characterization, and optimization of these valuable biocatalysts are based on a very limited number of fundamentally different methods with their respective strengths and weaknesses. Here, a (bio)chemical activity assay is described, which perfectly complements the other methods in this field. It enables continuous and high-throughput activity measurements of purified and unpurified quorum-quenching enzymes within several minutes. For this, the reaction products released by quorum-quenching lactonases and quorum-quenching acylases are converted either by a secondary enzyme or by autohydrolysis to l-homoserine. In turn, l-homoserine is detected by the previously described calcein assay, which is sensitive to α-amino acids with free N and C termini. Besides its establishment, the method was applied to the characterization of three previously undescribed quorum-quenching lactonases and variants thereof and to the identification of quorum-quenching acylase-expressing Escherichia coli clones in an artificial library. Furthermore, this study indicates that porcine aminoacylase 1 is not active toward N-acyl-l-homoserine lactones as published previously but instead converts the autohydrolysis product N-acyl-l-homoserine.ImportanceIn this study, a novel method is presented for the identification, characterization, and optimization of quorum-quenching enzymes that are active toward N-acyl-l-homoserine lactones. These are the most common communication molecules among Gram-negative proteobacteria. The activity assay is a highly valuable complement to the available analytical tools in this field. It will facilitate studies on the environmental impact of quorum-quenching enzymes and contribute to the development of therapeutic and technical applications of this promising enzyme class.

Dataset Information

Novel N-Acyl Homoserine Lactone-Degrading Bacteria Isolated From Penicillin-Contaminated Environments and Their Quorum-Quenching Activities.

Publications

Novel <i>N</i>-Acyl Homoserine Lactone-Degrading Bacteria Isolated From Penicillin-Contaminated Environments and Their Quorum-Quenching Activities.

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