About this Research Topic
Redox-active small molecules, such as antibiotics, vitamins and pigments, have been isolated from countless and diverse microbial strains, represent a wide variety of structures, and play different biological roles. Antibiotics such as bleomycin and phenazine derivatives have long attracted research interest due to their applications in medicine and agriculture. In addition to their roles as antibiotics and virulence factors, phenazines have been implicated in intercellular signaling and are known to activate microbial redox-senstitive transcription factors. Vitamin B12, produced only by prokaryotes, is the cofactor of diverse enzymes catalyzing vital functions in humans. Moreover, this compound has been shown to interact with regulatory RNA and DNA elements, leading to a conformational change within the respective nucleic acid.
Many academic and industrial research enterprises are motivated by the search for metabolites with novel activities or the intent to optimize large-scale production of such compounds. Antibiotics, for example, are used at high concentrations to achieve the desired clinical effect. Recent investigations have, however, shown that some of these compounds induce differential responses that are cell type- and concentration-dependent. As researchers continue to explore the effects of redox-active metabolites in the context of microbial community development and adaptation to stress, they are identifying signaling networks that enable these compounds to elicit specific genetic responses in producing and non-producing organisms.
Studies in the burgeoning field of microbial redox signaling have suggested that small molecules activate regulatory cascades both through indirect effects on the cellular redox environment and direct interactions with proteins or nucleic acids. They modulate for example the activity of two-component senor kinases, transcriptional regulators or small regulatory RNAs. To address the many unanswered questions regarding molecular and cellular mechanisms governing these interactions, researchers have developed and applied a diversity of sophisticated tools that include methods of structural biology, biophysics and chemistry to analyze the interaction between biomolecules at the atomic level. Modern imaging techniques additionally ensure an accurate in vivo monitoring of the development of microbial communities. Finally, the application of metabolomics, proteomics and transcriptomics allows the identification of new members within signaling networks.
The goal of this Frontiers Research Topic is to highlight new mechanisms that underpin the physiological effects of redox-active small molecules in microbial signaling pathways. It will focus on recent advances clarifying the interaction of these metabolites with other biomolecules, including sensory proteins and nucleic acids, and the resulting physiological response at the molecular, single-cell and/or microbial community level. The topic will be of high relevance not only for researchers in the field of basic science, but also of medicine and biotechnology.
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