Quorum Sensing in Cyanobacteria and the Origin of Blooms. Lessons for Human Pharmacology

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.

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Evidence of Quorum Sensing in Cyanobacteria by Homoserine Lactones: The Origin of Blooms

Water ◽

10.3390/w13131831 ◽

2021 ◽

Vol 13 (13) ◽

pp. 1831

Author(s):

Natalia Herrera ◽

Fernando Echeverri

Keyword(s):

Cell Proliferation ◽

Quorum Sensing ◽

Microcystis Aeruginosa ◽

Industrial Effluents ◽

Cyanobacterial Blooms ◽

Cylindrospermopsis Raciborskii ◽

Bacterial Communication ◽

Homoserine Lactones ◽

Exogenous Compounds ◽

Almost All

Although several theories have been postulated to explain cyanobacterial blooms, their biochemical origin has not yet been found. In this work, we explore the existence of bacterial communication, called quorum sensing, in Microcystis aeruginosa and Cylindrospermopsis raciborskii. Thus, the application of several known acylhomoserine lactones to cultures of both cyanobacteria causes profound metabolic. At 72 h post-application, some of them produced substantial increases in cell proliferation, while others were inhibitors. There was a correlation with colony-forming activity for most of them. According to ELISA analysis, the microcystin levels were increased with some lactones. However, there was a clear difference between M. aeruginosa and C. raciborskii culture since, in the first one, there was an inducing effect on cell proliferation, while in C. raciborskii, the effects were minor. Besides, there were compound inhibitors and inducers of microcystins production in M. aeruginosa, but almost all compounds were only inducers of saxitoxin production in C. raciborskii. Moreover, each lactone appears to be involved in a specific quorum sensing process. From these results, the formation of cyanobacterial blooms in dams and reservoirs could be explained since lactones may come from cyanobacteria and other sources as bacterial microflora-associated or exogenous compounds structurally unrelated to lactones, such as drugs, industrial effluents, and agrochemicals.

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Growth of Salmonella Enteritidis in the presence of quorum sensing signaling compounds produced by Pseudomonas aeruginosa

International Journal of Food Engineering ◽

10.1515/ijfe-2021-0089 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Weijia He ◽

Huamei Yang ◽

Xiang Wang ◽

Hongmei Li ◽

Qingli Dong

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Salmonella Enteritidis ◽

Culture Supernatant ◽

Lag Time ◽

Bacterial Communication ◽

Homoserine Lactones ◽

Positive Effects ◽

Kinetics Of

Abstract Quorum sensing (QS) can exist in food-related bacteria and potentially affect bacterial growth through acyl-homoserine lactones (AHLs). To verify the role of QS compounds in the cell-free supernatant, this study examined the effect of supernatant extracted from Pseudomonas aeruginosa culture on the growth kinetics of Salmonella Enteritidis. The results showed that the lag time (λ) of S. Enteritidis was apparently reduced (p < 0.05) under the influence of P. aeruginosa culture supernatant compared with the S. Enteritidis culture supernatant. HPLC-MS/MS test demonstrated that AHLs secreted by P. aeruginosa were mainly C14-HSL with a content of 85.71 μg/mL and a small amount of 3-oxo-C12-HSL. In addition, the commercially synthetic C14-HSL had positive effects on the growth of S. Enteritidis, confirming once again that the growth of S. Enteritidis was affected by AHL metabolized by other bacteria and the complexity of bacterial communication.

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Quorum Sensing of Acidophiles: A Communication System in Microorganisms

10.5772/intechopen.100572 ◽

2021 ◽

Author(s):

Xueyan Gao ◽

Jianqiang Lin ◽

Linxu Chen ◽

Jianqun Lin ◽

Xin Pang

Keyword(s):

Quorum Sensing ◽

Population Density ◽

Intercellular Communication ◽

Communication System ◽

Communication Systems ◽

Biological Function ◽

Regulatory Mechanism ◽

Signal Molecules ◽

Acidic Environment ◽

Cell Cooperation

Communication is important for organisms living in nature. Quorum sensing system (QS) are intercellular communication systems that promote the sociality of microbes. Microorganisms could promote cell-to-cell cooperation and population density to adapt to the changing environment through QS-mediated regulation that is dependent on the secretion and the detection of signal molecules (or called autoinducers). QS system is also discovered in acidophiles, a microorganism that is widely used in the bioleaching industry and can live in an acidic environment. An example is the LuxI/R-like QS system (AfeI/R) that has been reported in the chemoautotrophic species of the genus Acidithiobacillus. In this chapter, we will introduce the types and distribution of the QS system, and the biological function and regulatory mechanism of QS in acidophiles. We will also discuss the potential ecological function of QS system and the application value of the QS system in the control and regulation of the bioleaching process in the related industries and acid mine damage.

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IgY Targeting Bacterial Quorum-Sensing Molecules in Implant-Associated Infections

Molecules ◽

10.3390/molecules25174027 ◽

2020 ◽

Vol 25 (17) ◽

pp. 4027

Author(s):

Ulrike Dapunt ◽

Birgit Prior ◽

Christopher Oelkrug ◽

Jan Philippe Kretzer

Keyword(s):

Quorum Sensing ◽

Staphylococcus Epidermidis ◽

Biofilm Formation ◽

Major Complication ◽

Underlying Mechanism ◽

Bacterial Communication ◽

Bacterial Quorum Sensing ◽

Polysaccharide Intercellular Adhesion ◽

Bacterial Quorum ◽

Treatment Alternatives

Background: Implant-associated infections are still a major complication in the field of orthopedics. Bacteria can form biofilms on implant surfaces, making them more difficult to detect and treat. Since standard antibiotic therapy is often impaired in biofilm infections, particular interest is directed towards finding treatment alternatives. Biofilm-formation is a well-organized process during which bacteria communicate via quorum-sensing molecules (QSM). The aim of this study was to inhibit bacterial communication by directing avian IgY against specific QSM. Methods: Chicken were immunized against the following QSM: (1) AtlE, a member of the autolysin family which mediates attachment to a surface in Staphylococcus epidermidis; (2) GroEL, the bacterial heat shock protein; (3) PIA (polysaccharide intercellular adhesion), which is essential for cell–cell adhesion in biofilms. Staphylococcus epidermidis biofilms were grown and inhibition of biofilm-formation by IgYs was evaluated. Additionally, human osteoblasts were cultivated and biocompatibility of IgYs was tested. Results: We were able to demonstrate that all IgYs reduced biofilm-formation, also without prior immunization. Therefore, the response was probably not specific with regard to the QSM. Osteoblasts were activated by all IgYs which was demonstrated by microscopy and an increased release of IL-8. Conclusions: In conclusion, avian IgY inhibits biofilm-formation, though the underlying mechanism is not yet clear. However, adverse effects on local tissue cells (osteoblasts) were also observed.

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Innovative approaches to treat Staphylococcus aureus biofilm-related infections

Essays in Biochemistry ◽

10.1042/ebc20160056 ◽

2017 ◽

Vol 61 (1) ◽

pp. 61-70 ◽

Cited By ~ 17

Author(s):

Katharina Richter ◽

Freija Van den Driessche ◽

Tom Coenye

Keyword(s):

Staphylococcus Aureus ◽

Extracellular Matrix ◽

Antimicrobial Resistance ◽

Iron Metabolism ◽

Communication System ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Antibiofilm Activity ◽

Human Pathogen ◽

Bacterial Communication

Many bacterial infections in humans and animals are caused by bacteria residing in biofilms, complex communities of attached organisms embedded in an extracellular matrix. One of the key properties of microorganisms residing in a biofilm is decreased susceptibility towards antimicrobial agents. This decreased susceptibility, together with conventional mechanisms leading to antimicrobial resistance, makes biofilm-related infections increasingly difficult to treat and alternative antibiofilm strategies are urgently required. In this review, we present three such strategies to combat biofilm-related infections with the important human pathogen Staphylococcus aureus: (i) targeting the bacterial communication system with quorum sensing (QS) inhibitors, (ii) a ‘Trojan Horse’ strategy to disturb iron metabolism by using gallium-based therapeutics and (iii) the use of ‘non-antibiotics’ with antibiofilm activity identified through screening of repurposing libraries.

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Legionella spp. all ears? The broad occurrence of quorum sensing elements outside Legionella pneumophila

Genome Biology and Evolution ◽

10.1093/gbe/evab032 ◽

2021 ◽

Author(s):

Benjamin Herran ◽

Pierre Grève ◽

Jean-Marc Berjeaud ◽

Joanne Bertaux ◽

Alexandre Crépin

Keyword(s):

Quorum Sensing ◽

Legionella Pneumophila ◽

Communication System ◽

Histidine Kinase ◽

Genomic Region ◽

Membrane Receptors ◽

Intracellular Pathogen ◽

Sensing System ◽

The World ◽

Quorum Sensing System

Abstract Legionella spp. are ubiquitous bacteria principally found in water networks and around 20 species are implicated in Legionnaire’s disease. Among them, Legionella pneumophila is an intracellular pathogen of environmental protozoa, responsible for about 90% of cases in the world. Legionella pneumophila regulates in part its virulence by a quorum sensing system named “Legionella quorum sensing”, composed of a signal synthase LqsA, two histidine kinase membrane receptors LqsS and LqsT and a cytoplasmic receptor LqsR. To date, this communication system was only found in L. pneumophila. Here we investigated 58 Legionella genomes to determine the presence of a lqs cluster or homologous receptors using tblastn. This analysis revealed three categories of species: 19 harboured a complete lqs cluster, 20 did not possess lqsA but maintained the receptor lqsR and/or lqsS, and 19 did not have any of the lqs genes. No correlation was observed between pathogenicity and the presence of a quorum sensing system. We determined by RT-qPCR that the lqsA gene was expressed at least in four strains among different species available in our laboratory. Furthermore, we showed that the lqs genomic region was conserved even in species possessing only the receptors of the quorum sensing system, indicating an ancestral acquisition and various loss dynamics during evolution. This system could therefore function in inter-specific communication as well.

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Novel Quorum Sensing Activity in East Antarctic Soil Bacteria

10.1101/749861 ◽

2019 ◽

Author(s):

Sin Yin Wong ◽

James C. Charlesworth ◽

Nicole Benaud ◽

Brendan P. Burns ◽

Belinda C. Ferrari

Keyword(s):

Microbial Community ◽

Quorum Sensing ◽

Soil Bacteria ◽

Bacterial Species ◽

Survival Strategies ◽

Antarctic Soil ◽

Bacterial Communication ◽

Antarctic Soils ◽

Physiological Adaptations ◽

Antarctic Environment

ABSTRACTAntarctica, being the coldest, driest and windiest continent on Earth, represents the most extreme environment a living organism can thrive in. Under constant exposure to harsh environmental threats, terrestrial Antarctica remains home to a great diversity of microorganisms, indicating that the soil bacteria must have adapted a range of survival strategies that require cell-to-cell communication. Survival strategies include secondary metabolite production, biofilm formation, bioluminescence, symbiosis, conjugation, sporulation and motility, all of which are often regulated by quorum sensing (QS), a type of bacterial communication. Up to now, such mechanisms have not been explored in terrestrial Antarctica. Here, for the first time, LuxI/LuxR-based quorum sensing (QS) activity was delineated in soil bacterial isolates recovered from Adams Flat, in the Vestfold Hills region of East Antarctica. Interestingly, we identified the production of potential homoserine lactones (HSLs) ranging from medium to long chain length in 19 bacterial species using three biosensors, namely Agrobacterium tumefaciens NTL4, Chromobacterium violaceum CV026 and Escherichia coli MT102, in conjunction with thin layer chromatography (TLC). The majority of detectable HSLs were from gram-positive microorganisms not previously known to produce HSLs. This discovery further expands our understand of the microbial community capable of this type of communication, as well as providing insights into physiological adaptations of microorganisms that allow them to survive in the harsh Antarctic environment.IMPORTANCEQuorum sensing, a type of bacterial communication, is widely known to regulate many processes including those that confer survival advantage. However, little is known about communication by bacteria thriving within Antarctic soils. Employing a combination of bacteria biosensors, analytical techniques, and genome mining, we found a variety of Antarctic soil bacteria speaking a common language, via the LuxI/LuxR-based quorum sensing, thus potentially supporting survival in a mixed microbial community. This is the first report of quorum sensing activity in Antarctic soils and has provided a platform for studying physiological adaptations of microorganisms that allow them to not just survive but thrive in the harsh Antarctic environment.

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Bacterial Quorum-Sensing Signal Arrests Phytoplankton Cell Division and Impacts Virus-Induced Mortality

mSphere ◽

10.1128/msphere.00009-21 ◽

2021 ◽

Vol 6 (3) ◽

Author(s):

Scott B. Pollara ◽

Jamie W. Becker ◽

Brook L. Nunn ◽

Rene Boiteau ◽

Daniel Repeta ◽

...

Keyword(s):

Dna Damage ◽

Cell Division ◽

Quorum Sensing ◽

Heterotrophic Bacteria ◽

Marine Ecosystems ◽

Ecological Consequences ◽

Bacterial Communication ◽

Communication Signals ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum

ABSTRACT Interactions between phytoplankton and heterotrophic bacteria fundamentally shape marine ecosystems by controlling primary production, structuring marine food webs, mediating carbon export, and influencing global climate. Phytoplankton-bacterium interactions are facilitated by secreted compounds; however, linking these chemical signals, their mechanisms of action, and their resultant ecological consequences remains a fundamental challenge. The bacterial quorum-sensing signal 2-heptyl-4-quinolone (HHQ) induces immediate, yet reversible, cellular stasis (no cell division or mortality) in the coccolithophore Emiliania huxleyi; however, the mechanism responsible remains unknown. Using transcriptomic and proteomic approaches in combination with diagnostic biochemical and fluorescent cell-based assays, we show that HHQ exposure leads to prolonged S-phase arrest in phytoplankton coincident with the accumulation of DNA damage and a lack of repair despite the induction of the DNA damage response (DDR). While this effect is reversible, HHQ-exposed phytoplankton were also protected from viral mortality, ascribing a new role of quorum-sensing signals in regulating multitrophic interactions. Furthermore, our data demonstrate that in situ measurements of HHQ coincide with areas of enhanced micro- and nanoplankton biomass. Our results suggest bacterial communication signals as emerging players that may be one of the contributing factors that help structure complex microbial communities throughout the ocean. IMPORTANCE Bacteria and phytoplankton form close associations in the ocean that are driven by the exchange of chemical compounds. The bacterial signal 2-heptyl-4-quinolone (HHQ) slows phytoplankton growth; however, the mechanism responsible remains unknown. Here, we show that HHQ exposure leads to the accumulation of DNA damage in phytoplankton and prevents its repair. While this effect is reversible, HHQ-exposed phytoplankton are also relieved of viral mortality, elevating the ecological consequences of this complex interaction. Further results indicate that HHQ may target phytoplankton proteins involved in nucleotide biosynthesis and DNA repair, both of which are crucial targets for viral success. Our results support microbial cues as emerging players in marine ecosystems, providing a new mechanistic framework for how bacterial communication signals mediate interspecies and interkingdom behaviors.

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