The food-grade antimicrobial xanthorrhizol targets the enoyl-ACP reductase (FabI) in Escherichia coli

Background/Aims: We previously identified the Triclo1 fosmid in a functional metagenomic selection for clones that increased triclosan tolerance in Escherichia coli. The active enzyme encoded by Triclo1 is ucFabV. Although ucFabV is homologous to FabV from other organisms, ucFabV contains substitutions at key positions that would predict differences in substrate binding. Therefore, a detailed characterization of ucFabV was conducted to link its biochemical activity to its ability to confer reduced triclosan sensitivity. Methods: ucFabV and a catalytic mutant were purified and used to reduce crotonoyl-CoA in vitro. The mutant and wild-type enzymes were introduced into E. coli, and their ability to confer triclosan tolerance as well as suppress a temperature-sensitive mutant of FabI were measured. Results: Purified ucFabV, but not the mutant, reduced crotonoyl-CoA in vitro. The wild-type enzyme confers increased triclosan tolerance when introduced into E. coli, whereas the mutant remained susceptible to triclosan. Additionally, wild-type ucFabV, but not the mutant, functionally replaced FabI within living cells. Conclusion: ucFabV confers increased tolerance through its function as an enoyl-ACP reductase. Furthermore, ucFabV is capable of restoring viability in the presence of compromised FabI, suggesting ucFabV is likely facilitating an alternate step within fatty acid synthesis, bypassing FabI inhibition.

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Electrostatic Spraying of Food-Grade Organic and Inorganic Acids and Plant Extracts to Decontaminate Escherichia coli O157:H7 on Spinach and Iceberg Lettuce

Journal of Food Science ◽

10.1111/j.1750-3841.2012.02719.x ◽

2012 ◽

Vol 77 (7) ◽

pp. M391-M396 ◽

Cited By ~ 27

Author(s):

Vijayalakshmi Ganesh ◽

Navam S. Hettiarachchy ◽

Carl L. Griffis ◽

Elizabeth M. Martin ◽

Steven C. Ricke

Keyword(s):

Escherichia Coli ◽

Plant Extracts ◽

Escherichia Coli O157 ◽

Food Grade ◽

Electrostatic Spraying ◽

Iceberg Lettuce ◽

Inorganic Acids

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Recovery of microorganisms on fabric materials after low water temperature washing with non-oxidizing acidic bleaching formulation by culture method

Journal of Water and Health ◽

10.2166/wh.2014.194 ◽

2014 ◽

Vol 12 (3) ◽

pp. 418-425

Author(s):

Jaesung Lee ◽

John A. Lopes ◽

Melvin A. Pascall

Keyword(s):

Escherichia Coli ◽

Water Temperature ◽

Culture Method ◽

Listeria Innocua ◽

Cross Contamination ◽

Food Grade ◽

Washing Process ◽

Fabric Materials ◽

Washing Water ◽

Blend Fabric

The recovery of microorganisms to different fabrics was evaluated after a washing process combined with a food-grade non-oxidizing acidic formulation and low washing water temperature. Cotton, polyester and a polyester/cotton blend fabric samples were inoculated with Escherichia coli, Listeria innocua and Saccharomyces cerevisiae, then dried for 1 day. They were separately placed in a simulated fabric washer and decontaminated for 1 and 10 min with the acidic formulation at 23 °C water washing temperature. The combination of direct detecting and dilution methods was used to detect survivors on fabrics. The use of ≥0.1% acidic formulation in the washing process significantly increased the efficacy of the washing for all fabric samples. Microorganisms on the cotton and mixed fabric appeared to bind more strongly and were more resistant to the washing process. No viability was observed on the fabric swatches at 1 cfu/sample detection limit when the washing process was combined with 0.5% acidic formulation in the 10 min washing cycle. These findings can be used to increase the efficiency of sanitizing fabrics in an environmentally friendly way, for remove harmful microorganisms from them and reduce cross-contamination.

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