scholarly journals Can community-based signalling behaviour in Saccharomyces cerevisiae be called quorum sensing? A critical review of the literature

2019 ◽  
Vol 19 (5) ◽  
Author(s):  
Michela Winters ◽  
Nils Arneborg ◽  
Rudi Appels ◽  
Kate Howell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quorum Sensing ◽  
Cell Density ◽  
Critical Concentration ◽  
Threshold Value ◽  
Fungal Species ◽  
Signal Molecules ◽  
Critical Signal ◽  
Density Dependent ◽  
Intercellular Signalling

ABSTRACTQuorum sensing is a well-described mechanism of intercellular signalling among bacteria, which involves cell-density-dependent chemical signal molecules. The concentration of these quorum-sensing molecules increases in proportion to cell density until a threshold value is exceeded, which triggers a community-wide response. In this review, we propose that intercellular signalling mechanisms can be associated with a corresponding ecological interaction type based on similarities between how the interaction affects the signal receiver and producer. Thus, we do not confine quorum sensing, a specific form of intercellular signalling, to only cooperative behaviours. Instead, we define it as cell-density-dependent responses that occur at a critical concentration of signal molecules and through a specific signalling pathway. For fungal species, the medically important yeast Candida albicans has a well-described quorum sensing system, while this system is not well described in Saccharomyces cerevisiae, which is involved in food and beverage fermentations. The more precise definition for quorum sensing proposed in this review is based on the studies suggesting that S. cerevisiae may undergo intercellular signalling through quorum sensing. Through this lens, we conclude that there is a lack of evidence to support a specific signalling mechanism and a critical signal concentration of these behaviours in S. cerevisiae, and, thus, these features require further investigation.

scholarly journals Peptide signaling without feedback in signal production operates as a true quorum sensing communication system in Bacillus subtilis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Iztok Dogsa ◽  
Mihael Spacapan ◽  
Anna Dragoš ◽  
Tjaša Danevčič ◽  
Žiga Pandur ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Quorum Sensing ◽  
Cell Density ◽  
Communication System ◽  
Communication Systems ◽  
Feedback Loop ◽  
Signal Molecules ◽  
Specific Cell ◽  
Sharp Transition

AbstractBacterial quorum sensing (QS) is based on signal molecules (SM), which increase in concentration with cell density. At critical SM concentration, a variety of adaptive genes sharply change their expression from basic level to maximum level. In general, this sharp transition, a hallmark of true QS, requires an SM dependent positive feedback loop, where SM enhances its own production. Some communication systems, like the peptide SM-based ComQXPA communication system of Bacillus subtilis, do not have this feedback loop and we do not understand how and if the sharp transition in gene expression is achieved. Based on experiments and mathematical modeling, we observed that the SM peptide ComX encodes the information about cell density, specific cell growth rate, and even oxygen concentration, which ensure power-law increase in SM production. This enables together with the cooperative response to SM (ComX) a sharp transition in gene expression level and this without the SM dependent feedback loop. Due to its ultra-sensitive nature, the ComQXPA can operate at SM concentrations that are 100–1000 times lower than typically found in other QS systems, thereby substantially reducing the total metabolic cost of otherwise expensive ComX peptide.

scholarly journals Stringent Response Activates Quorum Sensing and Modulates Cell Density-Dependent Gene Expression inPseudomonas aeruginosa

2001 ◽  
Vol 183 (18) ◽  
pp. 5376-5384 ◽  
Author(s):  
Christian van Delden ◽  
Rachel Comte ◽  
And Marc Bally
Keyword(s):  
Gene Expression ◽  
Quorum Sensing ◽  
Cell Density ◽  
Stringent Response ◽  
Transcriptional Regulators ◽  
Homoserine Lactone ◽  
Density Dependent ◽  
Sensing Systems ◽  
Acid Analogue ◽  
Enhanced Expression

ABSTRACT During nutrient starvation, Escherichia coli elicits a stringent response involving the ribosome-associated protein RelA. Activation of RelA results in a global change in the cellular metabolism including enhanced expression of the stationary-phase sigma factor RpoS. In the human pathogen Pseudomonas aeruginosa, a complex quorum-sensing circuitry, linked to RpoS expression, is required for cell density-dependent production of many secreted virulence factors, including LasB elastase. Quorum sensing relies on the activation of specific transcriptional regulators (LasR and RhlR) by their corresponding autoinducers (3-oxo-C12-homoserine lactone [HSL] and C4-HSL), which function as intercellular signals. We found that overexpression of relA activated the expression of rpoS in P. aeruginosa and led to premature, cell density-independent LasB elastase production. We therefore investigated the effects of the stringent response on quorum sensing. Both lasR and rhlR gene expression and autoinducer synthesis were prematurely activated during the stringent response induced by overexpression of relA. Premature expression of lasR and rhlR was also observed when relA was overexpressed in a PAO1 rpoSmutant. The stringent response induced by the amino acid analogue serine hydroxamate (SHX) also led to premature production of the 3-oxo-C12-HSL autoinducer. This response to SHX was absent in a PAO1 relA mutant. These findings suggest that the stringent response can activate the two quorum-sensing systems of P. aeruginosa independently of cell density.

scholarly journals Quorum sensing and social networking in the microbial world

2009 ◽  
Vol 6 (40) ◽  
pp. 959-978 ◽  
Author(s):  
Steve Atkinson ◽  
Paul Williams
Keyword(s):  
Quorum Sensing ◽  
Social Networking ◽  
Communication Networks ◽  
Cell Communication ◽  
Signal Molecules ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Microbial World ◽  
Rich Diversity ◽  
Intercellular Signalling

For many years, bacterial cells were considered primarily as selfish individuals, but, in recent years, it has become evident that, far from operating in isolation, they coordinate collective behaviour in response to environmental challenges using sophisticated intercellular communication networks. Cell-to-cell communication between bacteria is mediated by small diffusible signal molecules that trigger changes in gene expression in response to fluctuations in population density. This process, generally referred to as quorum sensing (QS), controls diverse phenotypes in numerous Gram-positive and Gram-negative bacteria. Recent advances have revealed that bacteria are not limited to communication within their own species but are capable of ‘listening in’ and ‘broadcasting to’ unrelated species to intercept messages and coerce cohabitants into behavioural modifications, either for the good of the population or for the benefit of one species over another. It is also evident that QS is not limited to the bacterial kingdom. The study of two-way intercellular signalling networks between bacteria and both uni- and multicellular eukaryotes as well as between eukaryotes is just beginning to unveil a rich diversity of communication pathways.

scholarly journals Saccharomyces cerevisiae Requires CFF1 To Produce 4-Hydroxy-5-Methylfuran-3(2H)-One, a Mimic of the Bacterial Quorum-Sensing Autoinducer AI-2

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Julie S. Valastyan ◽  
Christina M. Kraml ◽  
Istvan Pelczer ◽  
Thomas Ferrante ◽  
Bonnie L. Bassler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quorum Sensing ◽  
Bacterial Species ◽  
Cell Communication ◽  
Communication Process ◽  
Signal Molecules ◽  
Catalytic Residue ◽  
Interspecies Communication ◽  
Content Type ◽  
Extracellular Signal

ABSTRACT Quorum sensing is a process of cell-to-cell communication that bacteria use to orchestrate collective behaviors. Quorum sensing depends on the production, release, and detection of extracellular signal molecules called autoinducers (AIs) that accumulate with increasing cell density. While most AIs are species specific, the AI called AI-2 is produced and detected by diverse bacterial species, and it mediates interspecies communication. We recently reported that mammalian cells produce an AI-2 mimic that can be detected by bacteria through the AI-2 receptor LuxP, potentially expanding the role of the AI-2 system to interdomain communication. Here, we describe a second molecule capable of interdomain signaling through LuxP, 4-hydroxy-5-methylfuran-3(2H)-one (MHF), that is produced by the yeast Saccharomyces cerevisiae. Screening the S. cerevisiae deletion collection revealed Cff1p, a protein with no known role, to be required for MHF production. Cff1p is proposed to be an enzyme, with structural similarity to sugar isomerases and epimerases, and substitution at the putative catalytic residue eliminated MHF production in S. cerevisiae. Sequence analysis uncovered Cff1p homologs in many species, primarily bacterial and fungal, but also viral, archaeal, and higher eukaryotic. Cff1p homologs from organisms from all domains can complement a cff1Δ S. cerevisiae mutant and restore MHF production. In all cases tested, the identified catalytic residue is conserved and required for MHF to be produced. These findings increase the scope of possibilities for interdomain interactions via AI-2 and AI-2 mimics, highlighting the breadth of molecules and organisms that could participate in quorum sensing. IMPORTANCE Quorum sensing is a cell-to-cell communication process that bacteria use to monitor local population density. Quorum sensing relies on extracellular signal molecules called autoinducers (AIs). One AI called AI-2 is broadly made by bacteria and used for interspecies communication. Here, we describe a eukaryotic AI-2 mimic, 4-hydroxy-5-methylfuran-3(2H)-one, (MHF), that is made by the yeast Saccharomyces cerevisiae, and we identify the Cff1p protein as essential for MHF production. Hundreds of viral, archaeal, bacterial, and eukaryotic organisms possess Cff1p homologs. This finding, combined with our results showing that homologs from all domains can replace S. cerevisiae Cff1p, suggests that like AI-2, MHF is widely produced. Our results expand the breadth of organisms that may participate in quorum-sensing-mediated interactions.

scholarly journals Clarifying intercellular signalling in yeast: Saccharomyces cerevisiae does not undergo a quorum sensing-dependent switch to filamentous growth

2021 ◽  
Author(s):  
Michela Pia Winters ◽  
Violetta Aru ◽  
Kate Howell ◽  
Nils Arneborg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quorum Sensing ◽  
Cell Density ◽  
Nitrogen Deficiency ◽  
Filamentous Growth ◽  
Metabolite Concentration ◽  
Cell Densities ◽  
Local Cell ◽  
Low Nitrogen ◽  
Nitrogen Conditions

Saccharomyces cerevisiae can alter its morphology to a filamentous form associated with unipolar budding in response to environmental stressors. Induction of filamentous growth is suggested under nitrogen deficiency in response to alcoholic signalling molecules through a quorum sensing mechanism. To investigate this claim, we analysed the budding pattern of S. cerevisiae cells over time under low nitrogen while concurrently measuring cell density and extracellular metabolite concentration. We found that the proportion of cells displaying unipolar budding increased between local cell densities of 4.8x106 and 5.3x107 cells/ml within 10 to 20 hours of growth. However, the observed increase in unipolar budding could not be reproduced when cells were prepared at the critical cell density and in conditioned media. Removing the nutrient restriction by growth in high nitrogen conditions also resulted in an increase in unipolar budding between local cell densities of 5.2x106 and 8.2x107 cells/ml within 10 to 20 hours of growth, but there were differences in metabolite concentration compared to the low nitrogen conditions. This suggests that neither cell density, metabolite concentration, nor nitrogen deficiency were necessary or sufficient to increase the proportion of unipolar budding cells. It is therefore unlikely that quorum sensing is the mechanism controlling the switch to filamentous growth in S. cerevisiae. Only a high concentration of the putative signalling molecule, 2-phenylethanol resulted in an increase in unipolar budding, but this concentration was not physiologically relevant. We suggest that the compound 2-phenylethanol acts through a toxicity mechanism, rather than quorum sensing, to induce filamentous growth.

scholarly journals The Vibrio cholerae Quorum-Sensing Protein VqmA Integrates Cell Density, Environmental, and Host-Derived Cues into the Control of Virulence

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Ameya A. Mashruwala ◽  
Bonnie L. Bassler
Keyword(s):  
Small Intestine ◽  
Quorum Sensing ◽  
Vibrio Cholerae ◽  
Cell Density ◽  
Chemical Communication ◽  
Bile Salts ◽  
Anaerobic Growth ◽  
Signal Molecules ◽  
Content Type ◽  
Collective Behaviors

ABSTRACT Quorum sensing is a chemical communication process in which bacteria use the production, release, and detection of signal molecules called autoinducers to orchestrate collective behaviors. The human pathogen Vibrio cholerae requires quorum sensing to infect the small intestine. There, V. cholerae encounters the absence of oxygen and the presence of bile salts. We show that these two stimuli differentially affect quorum-sensing function and, in turn, V. cholerae pathogenicity. First, during anaerobic growth, V. cholerae does not produce the CAI-1 autoinducer, while it continues to produce the DPO autoinducer, suggesting that CAI-1 may encode information specific to the aerobic lifestyle of V. cholerae. Second, the quorum-sensing receptor-transcription factor called VqmA, which detects the DPO autoinducer, also detects the lack of oxygen and the presence of bile salts. Detection occurs via oxygen-, bile salt-, and redox-responsive disulfide bonds that alter VqmA DNA binding activity. We propose that VqmA serves as an information processing hub that integrates quorum-sensing information, redox status, the presence or absence of oxygen, and host cues. In response to the information acquired through this mechanism, V. cholerae appropriately modulates its virulence output. IMPORTANCE Quorum sensing (QS) is a process of chemical communication that bacteria use to orchestrate collective behaviors. QS communication relies on chemical signal molecules called autoinducers. QS regulates virulence in Vibrio cholerae, the causative agent of the disease cholera. Transit into the human small intestine, the site of cholera infection, exposes V. cholerae to the host environment. In this study, we show that the combination of two stimuli encountered in the small intestine, the absence of oxygen and the presence of host-produced bile salts, impinge on V. cholerae QS function and, in turn, pathogenicity. We suggest that possessing a QS system that is responsive to multiple environmental, host, and cell density cues enables V. cholerae to fine-tune its virulence capacity in the human intestine.

scholarly journals Cell density-dependent linoleic acid toxicity to Saccharomyces cerevisiae

2011 ◽  
Vol 11 (5) ◽  
pp. 408-417 ◽  
Author(s):  
Túlio César Ferreira ◽  
Lídia Maria Pepe de Moraes ◽  
Élida Geralda Campos
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Linoleic Acid ◽  
Cell Density ◽  
Density Dependent ◽  
Acid Toxicity

scholarly journals The BpsIR Quorum-Sensing System of Burkholderia pseudomallei

2005 ◽  
Vol 187 (2) ◽  
pp. 785-790 ◽  
Author(s):  
Yan Song ◽  
Chao Xie ◽  
Yong-Mei Ong ◽  
Yunn-Hwen Gan ◽  
Kim-Lee Chua
Keyword(s):  
Quorum Sensing ◽  
Cell Density ◽  
Burkholderia Pseudomallei ◽  
Homoserine Lactone ◽  
Positive Regulation ◽  
Density Dependent ◽  
Sensing System ◽  
Quorum Sensing System

ABSTRACT BpsIR, a LuxIR quorum-sensing homolog, is required for optimal expression of virulence and secretion of exoproducts in Burkholderia pseudomallei. Cell density-dependent expression of bpsI and bpsR, the positive regulation of bpsIR expression by BpsR, and the synthesis of N-octanoyl-homoserine lactone (C8HSL) by BpsI are described in this report.

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