Phylogenetic identification of bacterial MazF toxin protein motifs among probiotic strains and foodborne pathogens and potential implications of engineered probiotic intervention in food

Xianghe Yan,Vijay K Juneja,Pina M Fratamico,Joshua B Gurtler,Jing Hu

doi:10.1186/2045-3701-2-39

Abstract

BackgroundToxin-antitoxin (TA) systems are commonly found in bacteria and Archaea, and it is the most common mechanism involved in bacterial programmed cell death or apoptosis. Recently, MazF, the toxin component of the toxin-antitoxin module, has been categorized as an endoribonuclease, or it may have a function similar to that of a RNA interference enzyme.ResultsIn this paper, with comparative data and phylogenetic analyses, we are able to identify several potential MazF-conserved motifs in limited subsets of foodborne pathogens and probiotic strains and further provide a molecular basis for the development of engineered/synthetic probiotic strains for the mitigation of foodborne illnesses. Our findings also show that some probiotic strains, as fit as many bacterial foodborne pathogens, can be genetically categorized into three major groups based on phylogenetic analysis of MazF. In each group, potential functional motifs are conserved in phylogenetically distant species, including foodborne pathogens and probiotic strains.ConclusionThese data provide important knowledge for the identification and computational prediction of functional motifs related to programmed cell death. Potential implications of these findings include the use of engineered probiotic interventions in food or use of a natural probiotic cocktail with specificity for controlling targeted foodborne pathogens.

Highlights

Toxin-antitoxin (TA) systems are commonly found in bacteria and Archaea, and it is the most common mechanism involved in bacterial programmed cell death or apoptosis
Commensal bacteria found in the GI tract might be key members of known or potential probiotic strains revealed in this ‘phylogenetic core’, which may include
It has been demonstrated that genomic GC-content is correlated with a number of factors [61], including genome size [62] from species such as Lactobacillus, which ranges from 1.8 to 3.4 Mb in length. This demonstrates that the GC-content and genome size of Lactobacillus genomes may have implications related to the biological complexity and adaptation of this genus, and could be due to the rate of recombination that has been extensively studied in the E. coli genome [63]

Summary

Introduction

Toxin-antitoxin (TA) systems are commonly found in bacteria and Archaea, and it is the most common mechanism involved in bacterial programmed cell death or apoptosis. The U.S Public Health Service has identified ten important foodborne pathogens causing human illnesses, including pathogenic strains of Escherichia coli, Salmonella, Listeria, Clostridium botulinum, Shigella, and Campylobacter, which are associated with more than 250 known foodborne diseases The human and chicken gut microbiome projects [7,8,9,10,11,12] have shed new light on the existence of a bacterial ‘phylogenetic core’ [13] consisting of a wide diversity of gastrointestinal bacteria by using new technologies such as generation sequencing, 16S rRNA screens, metagenomics, and metaproteomics. Commensal bacteria found in the GI tract might be key members of known or potential probiotic strains revealed in this ‘phylogenetic core’, which may include

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Conclusion