A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution

Aframian, Nitzan; Eldar, Avigdor

doi:10.1146/annurev-micro-012220-063740

Cited by 46 publications

(38 citation statements)

References 122 publications

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“…Thanks to quorum sensing mechanisms, cells can monitor environmental changes such as cell density and launch their adaptation response when required. Two quorum sensing mechanism superfamilies were described in Gram-positive bacteria (Aframian and Eldar 2020 ): the membrane receptor family (TCS) and the cytoplasmic receptor family (RRNPP). Systems belonging to both families were found in solventogenic clostridia (Fig.…”

Section: Sporulation Regulation In Solventogenic Clostridiamentioning

confidence: 99%

Sporulation in solventogenic and acetogenic clostridia

Diallo

Kengen

López-Contreras

2021

Appl Microbiol Biotechnol

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The Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.

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Section: Sporulation Regulation In Solventogenic Clostridiamentioning

confidence: 99%

Sporulation in solventogenic and acetogenic clostridia

Diallo

Kengen

López-Contreras

2021

Appl Microbiol Biotechnol

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“…QS is extremely well studied in many taxa, including Pseudomonas, Vibrio and Bacillus spp. 4,[15][16][17] . It is generally assumed that gene expression patterns and phenotypes observed at the group level are representative of what individual cells do within the population.…”

Section: Introductionmentioning

confidence: 99%

Pseudomonas aeruginosa reaches collective decisions via transient segregation of quorum sensing activities across cells

Jayakumar

Thomas

Brown

et al. 2021

Preprint

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Bacteria engage in a cell-to-cell communication process called quorum sensing (QS) to coordinate expression of cooperative exoproducts at the group level. While population-level QS-responses are well studied, we know little about commitments of single cells to QS. Here, we use flow cytometry to track the investment of Pseudomonas aeruginosa individuals into their intertwined Las and Rhl QS-systems. Using fluorescent reporters, we show that QS gene expression (signal synthase, receptor and exoproduct) was heterogenous and followed a gradual instead of a sharp temporal induction pattern. The simultaneous monitoring of two QS genes revealed that cells transiently segregate into low receptor (lasR) expressers that fully commit to QS, and high receptor expressers that delay QS commitment. Our mathematical model shows that such gene expression segregation could mechanistically be spurred by transcription factor limitation. In evolutionary terms, temporal segregation could serve as a QS-brake to allow for a bet-hedging strategy in unpredictable environments.

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“…In bacterial communities, signal propagation may be attenuated by signal uptake or degradation 9,10 (Supplementary Discussion, Section 1.3). With regard to signal uptake, we can broadly categorize quorum-sensing systems into two types of design [11][12][13] (Fig. 1b, Supplementary Fig.…”

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confidence: 99%

Short-range quorum sensing controls horizontal gene transfer at micron scale in bacterial communities

et al. 2021

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In bacterial communities, cells often communicate by the release and detection of small diffusible molecules, a process termed quorum-sensing. Signal molecules are thought to broadly diffuse in space; however, they often regulate traits such as conjugative transfer that strictly depend on the local community composition. This raises the question how nearby cells within the community can be detected. Here, we compare the range of communication of different quorum-sensing systems. While some systems support long-range communication, we show that others support a form of highly localized communication. In these systems, signal molecules propagate no more than a few microns away from signaling cells, due to the irreversible uptake of the signal molecules from the environment. This enables cells to accurately detect micron scale changes in the community composition. Several mobile genetic elements, including conjugative elements and phages, employ short-range communication to assess the fraction of susceptible host cells in their vicinity and adaptively trigger horizontal gene transfer in response. Our results underscore the complex spatial biology of bacteria, which can communicate and interact at widely different spatial scales.

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A Bacterial Tower of Babel: Quorum-Sensing Signaling Diversity and Its Evolution

Cited by 46 publications

References 122 publications

Sporulation in solventogenic and acetogenic clostridia

Sporulation in solventogenic and acetogenic clostridia

Pseudomonas aeruginosa reaches collective decisions via transient segregation of quorum sensing activities across cells

Short-range quorum sensing controls horizontal gene transfer at micron scale in bacterial communities

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