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Escherichia coli: Physiological Clues Which Turn On the Synthesis of Antimicrobial Molecules.

ABSTRACT: Zoonotic pathogens, like Shiga toxin-producing Escherichia coli (STEC) are a food safety and health risk. To battle the increasing emergence of virulent microbes, novel mitigation strategies are needed. One strategy being considered to combat pathogens is antimicrobial compounds produced by microbes, coined microcins. However, effectors for microcin production are poorly understood, particularly in the context of complex physiological responses along the gastro-intestinal tract (GIT). Previously, we identified an E. coli competitor capable of producing a strong diffusible antimicrobial with microcin-associated characteristics. Our objective was to examine how molecule production of this competitor is affected by physiological properties associated with the GIT, namely the effects of carbon source, bile salt concentration and growth phase. Using previously described liquid- and agar-based assays determined that carbon sources do not affect antimicrobial production of E. coli O103F. However, bile salt concentrations affected production significantly, suggesting that E. coli O103F uses cues along the GIT to modulate the expression of antimicrobial production. Furthermore, E. coli O103F produces the molecule during the exponential phase, contrary to most microcins identified to date. The results underscored the importance of experimental design to identify producers of antimicrobials. To detect antimicrobials, conventional microbiological methods can be a starting point, but not the gold standard.

SUBMITTER: Paquette SJ

PROVIDER: S-EPMC7712815 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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<i>Escherichia coli</i>: Physiological Clues Which Turn On the Synthesis of Antimicrobial Molecules.

Paquette Sarah-Jo SJ Reuter Tim T

Veterinary sciences 20201121 4

Zoonotic pathogens, like Shiga toxin-producing <i>Escherichia coli</i> (STEC) are a food safety and health risk. To battle the increasing emergence of virulent microbes, novel mitigation strategies are needed. One strategy being considered to combat pathogens is antimicrobial compounds produced by microbes, coined microcins. However, effectors for microcin production are poorly understood, particularly in the context of complex physiological responses along the gastro-intestinal tract (GIT). Pre ...[more]

PMID: 33233401

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Project description:BackgroundCyanobacteria possess several cytochrome P450s, but very little is known about their catalytic functions. CYP110 genes unique to cyanaobacteria are widely distributed in heterocyst-forming cyanobacteria including nitrogen-fixing genera Nostoc and Anabaena. We screened the biocatalytic functions of all P450s from three cyanobacterial strains of genus Nostoc or Anabaena using a series of small molecules that contain flavonoids, sesquiterpenes, low-molecular-weight drugs, and other aromatic compounds.ResultsEscherichia coli cells carrying each P450 gene that was inserted into the pRED vector, containing the RhFRed reductase domain sequence from Rhodococcus sp. NCIMB 9784 P450RhF (CYP116B2), were co-cultured with substrates and products were identified when bioconversion reactions proceeded. Consequently, CYP110E1 of Nostoc sp. strain PCC 7120, located in close proximity to the first branch point in the phylogenetic tree of the CYP110 family, was found to be promiscuous for the substrate range mediating the biotransformation of various small molecules. Naringenin and (hydroxyl) flavanones were respectively converted to apigenin and (hydroxyl) flavones, by functioning as a flavone synthase. Such an activity is reported for the first time in prokaryotic P450s. Additionally, CYP110E1 biotransformed the notable sesquiterpene zerumbone, anti-inflammatory drugs ibuprofen and flurbiprofen (methylester forms), and some aryl compounds such as 1-methoxy and 1-ethoxy naphthalene to produce hydroxylated compounds that are difficult to synthesize chemically, including novel compounds.ConclusionWe elucidated that the CYP110E1 gene, C-terminally fused to the P450RhF RhFRed reductase domain sequence, is functionally expressed in E. coli to synthesize a robust monooxygenase, which shows promiscuous substrate specificity (affinity) for various small molecules, allowing the biosynthesis of not only flavones (from flavanones) but also a variety of hydroxyl-small molecules that may span pharmaceutical and nutraceutical industries.

Dataset Information

Escherichia coli: Physiological Clues Which Turn On the Synthesis of Antimicrobial Molecules.

Publications

<i>Escherichia coli</i>: Physiological Clues Which Turn On the Synthesis of Antimicrobial Molecules.

Similar Datasets

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