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Updated: Mar 5, 2026

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds
Published on: August 8, 2025
Negative Regulation of Violacein Biosynthesis in Chromobacterium violaceum
Giulia Devescovi1, Milan Kojic2, Sonia Covaceuszach3
1International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
Abstract:
In Chromobacteium violaceum, the purple pigment violacein is under positive regulation by the N-acylhomoserine lactone CviI/R quorum sensing system and negative regulation by an uncharacterized putative repressor. In this study we report that the biosynthesis of violacein is negatively controlled by a novel repressor protein, VioS. The violacein operon is regulated negatively by VioS and positively by the CviI/R system in both C. violaceum and in a heterologous Escherichia coli genetic background. VioS does not regulate the CviI/R system and apart from violacein, VioS, and quorum sensing regulate other phenotypes antagonistically. Quorum sensing regulated phenotypes in C. violaceum are therefore further regulated providing an additional level of control.
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