Functional characterization of ycao in Escherichia coli C91 reveals its role in siderophore production, iron-limited growth, and antimicrobial activity

Dashti, Khadijah M, Ebrahim, Hussain, Vali, Leila ORCID: https://orcid.org/0009-0000-7740-3703 and Dashti, Ali A (2026) Functional characterization of ycao in Escherichia coli C91 reveals its role in siderophore production, iron-limited growth, and antimicrobial activity. Antibiotics, 15 (1). art:43. doi:10.3390/antibiotics15010043

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Abstract

Background: The emergence of antibiotic-resistant bacteria is one of the top health concerns. Escherichia coli is a Gram-negative bacterium that commonly causes severe infections. However, this research exposed its antibiotic-producing potential. Methods: Rifampicin-resistant mutants of E. coli C91 were generated to activate cryptic BGCs. Mutants (C91-R1, R2 and R3) were tested for antimicrobial production using agar-well diffusion assays. Metabolite profiling was performed by LC-MS/MS. Siderophore production was tested by construction of a Δycao deletion mutant. Growth of this mutant was assessed under iron-limited conditions versus iron-rich conditions using dipyridyl. qRT-PCR was used to analyze gene expression entB, mcmA and mchF. Genome mining was performed using antiSMASH and BAGEL4. Results: Compared to the wild type, Mutant C91-R1(S531L) displayed clear antibacterial activity against Staphylococcus aureus. LC-MS/MS revealed unique metabolites, including a novel peak at m/z 410.5, specific to the mutant C91-R1. A reduction in siderophore production of 61% was demonstrated in the Δycao mutant, and downregulation of entB, mcmA and mchF. Conclusions: Genome mining predicted non-ribosomal peptide, thiopeptide and polyketide BGCs. E. coli C91 offers antibiotic-producing potential that can be activated through ribosome-engineering-type approaches. Moreover, E. coli C91-R1 has unique metabolites and is considered as a promising candidate for novel antibiotic discovery.

Item Type:	Article
Article Type:	Article
Uncontrolled Keywords:	Antibiotics; Antimicrobials; Multidrug-resistance; Natural products; Secondary metabolites
Subjects:	Q Science > QH Natural history > QH301 Biology Q Science > QR Microbiology R Medicine > RM Therapeutics. Pharmacology
Divisions:	Schools and Research Institutes > School of Education, Health and Sciences
Depositing User:	Rhiannon Goodland
Date Deposited:	20 Jan 2026 15:40
Last Modified:	20 Jan 2026 16:00
URI:	https://eprints.glos.ac.uk/id/eprint/15760

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