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Quorum sensing

Yuepeng Sun, Yuntao Guan, Dan Wang, Kai Liang, Guangxue Wu
Two lab-scale nitrifying sequencing batch biofilm reactors, with (SBBR_CN) or without the addition of organics (SBBR_N), were operated to investigate potential roles of acyl homoserine lactone (AHL) based quorum sensing. AHLs of N-[(RS)-3-Hydroxybutyryl]-L-homoserine lactone, N-hexanoyl-L-homoserine lactone (C6 -HSL) and N-octanoyl-L-homoserine lactone (C8 -HSL) were detected in both reactors. C6 -HSL and C8 -HSL were also detected in batch experiments, especially with stimulated nitrite oxidizing bacteria activities...
March 7, 2018: Bioresource Technology
Takahiro Sawada, Miho Eguchi, Seiya Asaki, Ryota Kashiwagi, Kousuke Shimomura, Fumiko Taguchi, Hidenori Matsui, Mikihiro Yamamoto, Yoshiteru Noutoshi, Kazuhiro Toyoda, Yuki Ichinose
Our previous studies revealed that flagellar-motility-defective mutants such as ∆fliC of Pseudomonas syringae pv. tabaci 6605 (Pta6605) have remarkably reduced production of N-acyl-homoserine lactones (AHL), quorum-sensing molecules. To investigate the reason of loss of AHL production in ∆fliC mutant, we carried out transposon mutagenesis. Among approximately 14,000 transconjugants, we found 11 AHL production-recovered (APR) strains. In these APR strains, a transposon was inserted into either mexE or mexF, genes encoding for the multidrug efflux pump transporter MexEF-OprN, and mexT, a gene encoding a putative transcriptional activator for mexEF-oprN...
March 16, 2018: Molecular Genetics and Genomics: MGG
Angharad E Green, Alejandro Amézquita, Yvan Le-Marc, Matthew J Bull, Thomas R Connor, Eshwar Mahenthiralingam
Pseudomonas aeruginosa (P. aeruginosa) is a common contaminant associated with product recalls in the home and personal care (HPC) industry. Preservation systems are used to prevent spoilage and protect consumers, but greater knowledge is needed of preservative resistance mechanisms used by P. aeruginosa contaminants. We aimed to identify genetic pathways associated with preservative exposure by using an industrial P. aeruginosa strain and implementing RNA-Seq to understand gene expression changes in response to industry relevant conditions...
March 14, 2018: FEMS Microbiology Letters
David Williams, Joanne L Fothergill, Benjamin Evans, Jessica Caples, Sam Haldenby, Martin J Walshaw, Michael A Brockhurst, Craig Winstanley, Steve Paterson
Pseudomonas aeruginosa chronic infections of cystic fibrosis (CF) airways are a paradigm for within-host evolution with abundant evidence for rapid evolutionary adaptation and diversification. Recently emerged transmissible strains have spread globally, with the Liverpool Epidemic Strain (LES) the most common strain infecting the UK CF population. Previously we have shown that highly divergent lineages of LES can be found within a single infection, consistent with super-infection among a cross-sectional cohort of patients...
March 16, 2018: Microbial Genomics
Baruch B Hertzog, Yael Kaufman, Debabrata Biswas, Miriam Ravins, Poornima Ambalavanan, Reuven Wiener, Veronique Angeli, Swaine L Chen, Emanuel Hanski
Bacteria use quorum sensing (QS) to regulate gene expression. We identified a group A Streptococcus (GAS) strain possessing the QS system sil, which produces functional bacteriocins, through a sequential signaling pathway integrating host and bacterial signals. Host cells infected by GAS release asparagine (ASN), which is sensed by the bacteria to alter its gene expression and rate of proliferation. We show that upon ASN sensing, GAS upregulates expression of the QS autoinducer peptide SilCR. Initial SilCR expression activates the autoinduction cycle for further SilCR production...
March 14, 2018: Cell Host & Microbe
Vitor Cabral, Karina B Xavier
Bacterial sensing is important for perceiving environmental cues and activating responses. In this issue of Cell Host & Microbe, Hertzog et al. (2018) show that group A Streptococcus can couple the ability to respond to host cues with autoinduction of a quorum sensing system, leading to killing of bacterial competitors.
March 14, 2018: Cell Host & Microbe
Valerie F L Yong, Min Min Soh, Tavleen Kaur Jaggi, Micheál Mac Aogáin, Sanjay H Chotirmall
Pseudomonas aeruginosa is a major pathogen responsible for both acute and chronic infection. Known as a colonising pathogen of the cystic fibrosis (CF) lung, it is implicated in other settings such as bronchiectasis. It has the ability to cause acute disseminated or localised infection particularly in the immunocompromised. Human hormones have been highlighted as potential regulators of bacterial virulence through crosstalk between analogous "quorum sensing" (QS) systems present in the bacteria that respond to mammalian hormones...
March 14, 2018: Archivum Immunologiae et Therapiae Experimentalis
Manuel R Gonzalez, Verena Ducret, Sara Leoni, Betty Fleuchot, Paris Jafari, Wassim Raffoul, Lee A Applegate, Yok-Ai Que, Karl Perron
Pseudomonas aeruginosa is a severe opportunistic pathogen and is one of the major causes of hard to treat burn wound infections. Herein we have used an RNA-seq transcriptomic approach to study the behavior of P. aeruginosa PAO1 growing directly on human burn wound exudate. A chemical analysis of compounds used by this bacterium, coupled with kinetics expression of central genes has allowed us to obtain a global view of P. aeruginosa physiological and metabolic changes occurring while growing on human burn wound exudate...
2018: Frontiers in Cellular and Infection Microbiology
Huicong Yan, Meizhen Wang, Feng Sun, Ajai A Dandekar, Dongsheng Shen, Na Li
Pseudomonas aeruginosa uses quorum sensing (QS) to regulate the production of public goods such as the secreted protease elastase. P. aeruginosa requires the LasI-LasR QS circuit to induce elastase and enable growth on casein as the sole carbon and energy source. The LasI-LasR system also induces a second QS circuit, the RhlI-RhlR system. During growth on casein, LasR-mutant social cheaters emerge, and this can lead to a population collapse. In a minimal medium containing ammonium sulfate as a nitrogen source, populations do not collapse, and cheaters and cooperators reach a stable equilibrium; however, without ammonium sulfate, cheaters overtake the cooperators and populations collapse...
2018: Frontiers in Microbiology
Nishanth Makthal, Hackwon Do, Arica R VanderWal, Randall J Olsen, James M Musser, Muthiah Kumaraswami
Bacterial virulence factor production is a highly coordinated process. The temporal pattern of bacterial gene expression varies in different host anatomic sites to overcome niche-specific challenges. The human pathogen group A streptococcus (GAS) produces a potent secreted protease, SpeB, that is crucial for pathogenesis. Recently, we discovered that a quorum-sensing pathway comprised of a leaderless short peptide, SpeB-inducing peptide (SIP), and cytosolic global regulator, RopB, controls speB expression in concert with bacterial population density...
March 12, 2018: Infection and Immunity
Jin-Wei Zhou, Tong-Tong Chen, Xiao-Juan Tan, Ji-Yang Sheng, Ai-Qun Jia
Pseudomonas aeruginosa infection is a serious disease in cystic fibrosis (CF) patients and is difficult to cure due to biofilm persistence and emerging multidrug resistance. Considering the essential role of quorum sensing (QS) in P. aeruginosa infections, the enhanced effects between quorum sensing inhibitor (QSI) resveratrol and several antibiotics against P. aeruginosa PAO1 were investigated. Crystal violet staining assay revealed that the biofilms of P. aeruginosa PAO1 grown in the presence of resveratrol were more susceptible to aminoglycoside antibiotics...
March 9, 2018: International Journal of Antimicrobial Agents
Archana Ram, Andrew W Lo
Bacteria are easily characterizable model organisms with an impressively complicated set of abilities. Among them is quorum sensing, a cell-cell signaling system that may have a common evolutionary origin with eukaryotic cell-cell signaling. The two systems are behaviorally similar, but quorum sensing in bacteria is more easily studied in depth than cell-cell signaling in eukaryotes. Because of this comparative ease of study, bacterial dynamics are also more suited to direct interpretation than eukaryotic dynamics, e...
2018: Frontiers in Computational Neuroscience
Jobina Rajkumari, Subhomoi Borkotoky, Ayaluru Murali, Kitlangki Suchiang, Saswat Kumar Mohanty, Siddhardha Busi
The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P...
March 8, 2018: Microbial Pathogenesis
Manmohit Kalia, Vivek Kumar Yadav, Pradeep Kumar Singh, Deepmala Sharma, Shahid Suhail Narvi, Vishnu Agarwal
AIMS: Pseudomonas aeruginosa is a well-known pathogen responsible for various infections due to its capability to develop biofilm and various virulent phenotypes that are regulated by quorum sensing. Pathogenesis of the bacteria may be halted by interfering with the signaling molecules and the quorum sensing receptors. Therefore, the present study explores the potential of parthenolide, a sesquiterpene lactone of feverfew plant, as a promising candidate against P. aeruginosa PAO1 associated virulence factors and biofilm...
March 7, 2018: Life Sciences
Samantha Haller, Adrien Franchet, Abdul Hakkim, Jing Chen, Eliana Drenkard, Shen Yu, Stefanie Schirmeier, Zi Li, Nelson Martins, Frederick M Ausubel, Samuel Liégeois, Dominique Ferrandon
When Drosophila melanogaster feeds on Pseudomonas aeruginosa , some bacteria cross the intestinal barrier and eventually proliferate in the hemocoel. This process is limited by hemocytes through phagocytosis. P. aeruginosa requires the quorum-sensing regulator RhlR to elude the cellular immune response of the fly. RhlI synthesizes the autoinducer signal that activates RhlR. Here, we show that rhlI mutants are unexpectedly more virulent than rhlR mutants, both in fly and in nematode intestinal infection models, suggesting that RhlR has RhlI-independent functions...
March 9, 2018: EMBO Reports
Siphathele Sibanda, Stanford Kwenda, Collins K Tanui, Divine Y Shyntum, Teresa A Coutinho, Lucy N Moleleki
Pantoea ananatis LMG 2665T synthesizes and utilizes acyl homoserine lactones (AHLs) for signalling. The complete set of genes regulated by the EanI/R quorum sensing (QS) system in this strain is still not fully known. In this study, RNA-sequencing (RNA-seq) was used to identify the EanI/R regulon in LMG 2665T . Pairwise comparisons of LMG 2665T in the absence of AHLs (Optical density (OD)600 = 0.2) and in the presence of AHLs (OD600 = 0.5) were performed. Additionally, pairwise comparisons of LMG 2665T and its QS mutant at OD600 = 0...
March 7, 2018: Genes
Tânia Raquel Rodrigues Grainha, Paula Alexandra da Silva Jorge, Martín Pérez-Pérez, Gael Pérez Rodríguez, Maria Olívia Baptista Oliveira Pereira, Anália Maria Garcia Lourenço
The complex virulence attributes of Candida albicans are an attractive target to exploit in the development of new antifungals and anti-virulence strategies to combat C. albicans infections. Particularly, quorum-sensing (QS) has been reported as critical for virulence regulation in C. albicans. This work presents two knowledge networks with up-to-date information about QS regulation and experimentally tested anti-QS and anti-virulence agents for C. albicans. A semi-automatic bioinformatics workflow that combines literature mining and expert curation was used to retrieve otherwise scattered information from the scientific literature...
March 6, 2018: FEMS Yeast Research
J Janata, Z Kamenik, R Gazak, S Kadlcik, L Najmanova
Covering: up to 2017This review covers the biosynthetic and evolutionary aspects of lincosamide antibiotics, antitumour pyrrolobenzodiazepines (PBDs) and the quorum-sensing molecule hormaomycin. These structurally and functionally diverse groups of complex natural products all incorporate rarely occurring 4-alkyl-l-proline derivatives (APDs) biosynthesized from l-tyrosine through an unusual specialized pathway catalysed by a common set of six proteins named Apd1-Apd6. We give an overview of APD formation, which involves unusual enzyme activities, and its incorporation, which is based either on nonribosomal peptide synthetase (PBDs, hormaomycin) or a unique hybrid ergothioneine-dependent condensation system followed by mycothiol-dependent sulphur atom incorporation (lincosamides)...
March 8, 2018: Natural Product Reports
Martin S Bojer, Søren Lindemose, Martin Vestergaard, Hanne Ingmer
Incomplete killing of bacterial pathogens by antibiotics is an underlying cause of treatment failure and accompanying complications. Among those avoiding chemotherapy are persisters being individual cells in a population that for extended periods of time survive high antibiotic concentrations proposedly by being in a quiescent state refractory to antibiotic killing. While investigating the human pathogen Staphylococcus aureus and the influence of growth phase on persister formation, we noted that spent supernatants of stationary phase cultures of S...
2018: Frontiers in Microbiology
Xiaoguang Liu, Xiaoli Yu, Yang Yang, Stephan Heeb, Shao Gao, Kok Gan Chan, Miguel Cámara, Kexiang Gao
The antibiotic pyrrolnitrin (PRN) is a tryptophan-derived secondary metabolite that plays an important role in the biocontrol of plant diseases due to its broad-spectrum of antimicrobial activities. The PRN biosynthetic gene cluster remains to be characterised in Serratia plymuthica, though it is highly conserved in PRN-producing bacteria. To better understand PRN biosynthesis and its regulation in Serratia, the prnABCD operon from S. plymuthica G3 was cloned, sequenced and expressed in Escherichia coli DH5α...
March 6, 2018: Applied Microbiology and Biotechnology
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