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FEMS Microbiology Reviews Jul 2014Membrane-spanning signaling pathways enable bacteria to alter gene expression in response to extracytoplasmic stimuli. Many such pathways are cell-surface signaling... (Review)
Review
Membrane-spanning signaling pathways enable bacteria to alter gene expression in response to extracytoplasmic stimuli. Many such pathways are cell-surface signaling (CSS) systems, which are tripartite molecular devices that allow Gram-negative bacteria to transduce an extracellular stimulus into a coordinated transcriptional response. Typically, CSS systems are composed of the following: (1) an outer membrane receptor, which senses the extracellular stimulus; (2) a cytoplasmic membrane-spanning protein involved in signal transduction from the periplasm to the cytoplasm; and (3) an extracytoplasmic function (ECF) sigma factor that initiates expression of the stimulus-responsive gene(s). Members of genus Pseudomonas provide a paradigmatic example of how CSS systems contribute to the global control of gene expression. Most CSS systems enable self-regulated uptake of iron via endogenous (pyoverdine) or exogenous (xenosiderophores, heme, and citrate) carriers. Some are also implicated in virulence, biofilm formation, and cell-cell interactions. Incorporating insights from the well-characterized alginate regulatory circuitry, this review will illustrate common themes and variations at the level of structural and functional properties of Pseudomonas CSS systems. Control of the expression and activity of ECF sigma factors are central to gene regulation via CSS, and the variety of intrinsic and extrinsic factors influencing these processes will be discussed.
Topics: Cell Membrane; Gene Expression Regulation, Bacterial; Iron; Pseudomonas; Sigma Factor; Signal Transduction; Stress, Physiological
PubMed: 24923658
DOI: 10.1111/1574-6976.12078 -
Current Opinion in Chemical Biology Aug 2023While the list of small molecules known to be secreted by environmental microbes continues to grow, our understanding of their in situ biological functions remains... (Review)
Review
While the list of small molecules known to be secreted by environmental microbes continues to grow, our understanding of their in situ biological functions remains minimal. The time has come to develop a framework to parse the meaning of these "secondary metabolites," which are ecologically ubiquitous and have direct applications in medicine and biotechnology. Here, we focus on a particular subset of molecules, redox active metabolites (RAMs), and review the well-studied phenazines as archetypes of this class. We argue that efforts to characterize the chemical, physical and biological makeup of the microenvironments, wherein these molecules are produced, coupled with measurements of the molecules' basic chemical properties, will enable significant progress in understanding the precise roles of novel RAMs.
Topics: Pseudomonas aeruginosa; Oxidation-Reduction
PubMed: 37201291
DOI: 10.1016/j.cbpa.2023.102320 -
Journal of Medicinal Chemistry Dec 2018Antimicrobial resistance (AMR) is a serious threat to public health globally, manifested by the frequent emergence of multidrug resistant pathogens that render current... (Review)
Review
Antimicrobial resistance (AMR) is a serious threat to public health globally, manifested by the frequent emergence of multidrug resistant pathogens that render current chemotherapy inadequate. Health organizations worldwide have recognized the severity of this crisis and implemented action plans to contain its adverse consequences and prolong the utility of conventional antibiotics. Hence, there is a pressing need for new classes of antibacterial agents with novel modes of action. Quorum sensing (QS), a communication system employed by bacterial populations to coordinate virulence gene expression, is a potential target that has been intensively investigated over the past decade. This Perspective will focus on recent advances in targeting the three main quorum sensing systems ( las, rhl, and pqs) of a major opportunistic human pathogen, Pseudomonas aeruginosa, and will specifically evaluate the medicinal chemistry strategies devised to develop QS inhibitors from a drug discovery perspective.
Topics: Drug Discovery; Molecular Targeted Therapy; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 29999316
DOI: 10.1021/acs.jmedchem.8b00540 -
Cell Metabolism Jun 2020Itaconate is an immunometabolite with anti-inflammatory and anti-microbial properties. Riquelme et al. (2020) demonstrate that pathogenic Pseudomonas aeruginosa drives...
Itaconate is an immunometabolite with anti-inflammatory and anti-microbial properties. Riquelme et al. (2020) demonstrate that pathogenic Pseudomonas aeruginosa drives itaconate production by macrophages, which it then uses as a carbon source for biofilm formation, allowing it to persist during infection and suppress inflammation.
Topics: Biofilms; Pseudomonas; Pseudomonas aeruginosa; Succinates
PubMed: 32492389
DOI: 10.1016/j.cmet.2020.05.005 -
Microbial Biotechnology May 2018Bacteria of the genus Pseudomonas are widespread in nature. In the last decades, members of this genus, especially Pseudomonas aeruginosa and Pseudomonas putida, have... (Comparative Study)
Comparative Study Review
Bacteria of the genus Pseudomonas are widespread in nature. In the last decades, members of this genus, especially Pseudomonas aeruginosa and Pseudomonas putida, have acquired great interest because of their interactions with higher organisms. Pseudomonas aeruginosa is an opportunistic pathogen that colonizes the lung of cystic fibrosis patients, while P. putida is a soil bacterium able to establish a positive interaction with the plant rhizosphere. Members of Pseudomonas genus have a robust metabolism for amino acids and organic acids as well as aromatic compounds; however, these microbes metabolize a very limited number of sugars. Interestingly, they have three-pronged metabolic system to generate 6-phosphogluconate from glucose suggesting an adaptation to efficiently consume this sugar. This review focuses on the description of the regulatory network of glucose utilization in Pseudomonas, highlighting the differences between P. putida and P. aeruginosa. Most interestingly, It is highlighted a functional link between glucose assimilation and exotoxin A production in P. aeruginosa. The physiological relevance of this connection remains unclear, and it needs to be established whether a similar relationship is also found in other bacteria.
Topics: Gene Expression Regulation, Bacterial; Glucose; Metabolic Networks and Pathways; Pseudomonas aeruginosa; Pseudomonas putida; Transcription Factors
PubMed: 29607620
DOI: 10.1111/1751-7915.13263 -
Journal of Hazardous Materials Feb 2021Since the ban on the use of asbestos due to its carcinogenic properties, the removal of asbestos cement, representing the major asbestos-containing waste, has proven to...
Since the ban on the use of asbestos due to its carcinogenic properties, the removal of asbestos cement, representing the major asbestos-containing waste, has proven to be a challenge in most industrial countries. Asbestos-containing products are mainly disposed of in landfills and have remained untreated. Bioremediation involving bacteria previously reported the ability of Pseudomonas aeruginosa to release iron from flocking asbestos waste through a siderophore-driven mechanism. We examined the involvement of siderophore-producing Pseudomonas in the biodeterioration of asbestos cement. Iron and magnesium solubilization were evaluated by specific siderophore-producing mutants. The absence of one of the two siderophores affected iron extraction, whereas equivalent dissolution as that of the control was observed in the absence of siderophore. Both pyoverdine and pyochelin biosynthesis was repressed in the presence of asbestos cement, suggesting iron bioavailability from the waste. We compared the efficiency of various pyoverdines to scavenge iron from asbestos cement waste that revealed the efficiency of all pyoverdines. Pyoverdines were efficient in iron removal extracted continuously, with no evident extraction limit, in long-term weathering experiments with these pyoverdines. The optimization of pyoverdine-asbestos weathering may allow the development of a bioremediation process to avoid the disposal of such waste in landfills.
Topics: Asbestos; Iron; Pseudomonas; Pseudomonas aeruginosa; Siderophores
PubMed: 32853889
DOI: 10.1016/j.jhazmat.2020.123699 -
Natural Product Reports Jan 2020Bacteria of the genus Pseudomonas are ubiquitous in nature. Pseudomonads display a fascinating metabolic diversity, which correlates with their ability to colonize an... (Review)
Review
Bacteria of the genus Pseudomonas are ubiquitous in nature. Pseudomonads display a fascinating metabolic diversity, which correlates with their ability to colonize an extremely wide range of ecological niches. As a result, these bacteria are a prolific source of natural products. Biosynthesis of the latter is often orchestrated by arrays of chemical signals arising from intraspecies communication or interspecies relationships with bacteria, fungi, amoebae, plants, and insects. Especially nonribosomal lipopeptides, which have diverse biological activities, play important roles in the lifestyle of pseudomonads. In this review, we will focus on the molecular structures, properties, biosynthetic pathways, and biological functions of pseudomonal lipopeptides. This review is not only addressed to bio/chemists rather it serves as a comprehensive guide for all researchers (micro/biologists, ecologists, and environmental scientists) working in this multidisciplinary field.
Topics: Host-Pathogen Interactions; Lipopeptides; Molecular Structure; Plants; Pseudomonadaceae; Pseudomonas; Rhizosphere; Ribosomes; Soil Microbiology
PubMed: 31436775
DOI: 10.1039/c9np00022d -
Molecular Microbiology Feb 2022Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharides, the production of which...
Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharides, the production of which is often controlled by the secondary messenger c-di-GMP. Mechanisms of mat formation have been particularly well characterized in Pseudomonas fluorescens SBW25; stimuli or mutations that increase c-di-GMP production by diguanylate cyclases (WspR, AwsR, and MwsR) result in the secretion of cellulose and mat formation. Here, we characterize and compare mat formation in two close relatives of SBW25: Pseudomonas simiae PICF7 and P. fluorescens A506. We find that PICF7-the strain more closely related to SBW25-can form mats through mutations affecting the activity of the same three diguanylate cyclases as SBW25. However, instead of cellulose, these mutations activate production of the exopolysaccharide Pel. We also provide evidence for at least two further-as yet uncharacterized-routes to mat formation by PICF7. P. fluorescens A506, while retaining the same mutational routes to mat formation as SBW25 and PICF7, preferentially forms mats by a semi-heritable mechanism that culminates in Psl and Pga over-production. Our results demonstrate a high level of evolutionary flexibility in the molecular and structural routes to mat formation, even among close relatives.
Topics: Biofilms; Biological Evolution; Cyclic GMP; Mutation; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas fluorescens
PubMed: 34856020
DOI: 10.1111/mmi.14855 -
Current Microbiology Nov 2016Emergence and worldwide spreading of resistant bacteria to antibiotic have raised the importance for finding therapeutic alternative to compensate antibiotic drawbacks.... (Review)
Review
Emergence and worldwide spreading of resistant bacteria to antibiotic have raised the importance for finding therapeutic alternative to compensate antibiotic drawbacks. Quorum sensing (QS) is a cell-to-cell communication involved in the development of various common bacterial behaviors including virulence factors expression, and targeting QS seems to be relevant to the struggle against bacterial infection. In this report, relevant literature on intrication of QS system and antimicrobial sensitivity mechanisms in P. aeruginosa PAO1 are reviewed.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 27449213
DOI: 10.1007/s00284-016-1101-1 -
Biotechnology Journal Mar 2021Growing environmental concern sparks renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs)... (Review)
Review
Growing environmental concern sparks renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in the central metabolism of producer bacteria, as they act as dynamic reservoirs of carbon and reducing equivalents. PHAs continue to attract industrial attention as a starting point toward renewable, biodegradable, biocompatible, and versatile thermoplastic and elastomeric materials. Pseudomonas species have been known for long as efficient biopolymer producers, especially for medium-chain-length PHAs. The surge of synthetic biology and metabolic engineering approaches in recent years offers the possibility of exploiting the untapped potential of Pseudomonas cell factories for the production of tailored PHAs. In this article, an overview of the metabolic and regulatory circuits that rule PHA accumulation in Pseudomonas putida is provided, and approaches leading to the biosynthesis of novel polymers (e.g., PHAs including nonbiological chemical elements in their structures) are discussed. The potential of novel PHAs to disrupt existing and future market segments is closer to realization than ever before. The review is concluded by pinpointing challenges that currently hinder the wide adoption of bio-based PHAs, and strategies toward programmable polymer biosynthesis from alternative substrates in engineered P. putida strains are proposed.
Topics: Carbon; Metabolic Engineering; Polyhydroxyalkanoates; Pseudomonas; Pseudomonas putida
PubMed: 33085217
DOI: 10.1002/biot.202000165