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Science (New York, N.Y.) Mar 2021Microbial production of antibiotics is common, but our understanding of their roles in the environment is limited. In this study, we explore long-standing observations...
Microbial production of antibiotics is common, but our understanding of their roles in the environment is limited. In this study, we explore long-standing observations that microbes increase the production of redox-active antibiotics under phosphorus limitation. The availability of phosphorus, a nutrient required by all life on Earth and essential for agriculture, can be controlled by adsorption to and release from iron minerals by means of redox cycling. Using phenazine antibiotic production by pseudomonads as a case study, we show that phenazines are regulated by phosphorus, solubilize phosphorus through reductive dissolution of iron oxides in the lab and field, and increase phosphorus-limited microbial growth. Phenazines are just one of many examples of phosphorus-regulated antibiotics. Our work suggests a widespread but previously unappreciated role for redox-active antibiotics in phosphorus acquisition and cycling.
Topics: Anti-Bacterial Agents; Batch Cell Culture Techniques; Biological Availability; Oxidation-Reduction; Phenazines; Phosphorus; Pseudomonas
PubMed: 33674490
DOI: 10.1126/science.abd1515 -
ChemMedChem Jun 2022Pseudomonas aeruginosa is a pathogenic bacterium, responsible for a large portion of nosocomial infections globally and designated as critical priority by the World... (Review)
Review
Pseudomonas aeruginosa is a pathogenic bacterium, responsible for a large portion of nosocomial infections globally and designated as critical priority by the World Health Organisation. Its characteristic carbohydrate-binding proteins LecA and LecB, which play a role in biofilm-formation and lung-infection, can be targeted by glycoconjugates. Here we review the wide range of inhibitors for these proteins (136 references), highlighting structural features and which impact binding affinity and/or therapeutic effects, including carbohydrate selection; linker length and rigidity; and scaffold topology, particularly for multivalent candidates. We also discuss emerging therapeutic strategies, which build on targeting of LecA and LecB, such as anti-biofilm activity, anti-adhesion and drug-delivery, with promising prospects for medicinal chemistry.
Topics: Biofilms; Carbohydrates; Glycoconjugates; Lectins; Pseudomonas aeruginosa
PubMed: 35426976
DOI: 10.1002/cmdc.202200081 -
International Journal of Systematic and... Sep 2021The evolutionary relationships among species of the family were examined based on 255 available genomes representing >85 % of the species from this family. In a...
Phylogenomic and comparative genomic analyses of species of the family : Proposals for the genera gen. nov. and gen. nov., merger of the genus with the genus , and transfer of some misclassified species of the genus into other genera.
The evolutionary relationships among species of the family were examined based on 255 available genomes representing >85 % of the species from this family. In a phylogenetic tree based on concatenated sequences of 118 core proteins, most species of the genus grouped within one large cluster which also included members of the genera and . Within this large cluster 18-30 clades/subclades of species of the genus consisting of between 1 and 36 species, were observed. However, a number of species of the genus branched outside of this main cluster and were interspersed among other genera of the family . This included a strongly supported clade (Pertucinogena clade) consisting of 19 mainly halotolerant species. The distinctness of this clade from all other members of the family is strongly supported by 24 conserved signature indels (CSIs) in diverse proteins that are exclusively found in all members of this clade. Nine uncharacterized members of the genus also shared these CSIs and they branched within the Pertucinogena clade, indicating their affiliation to this clade. On the basis of the strong evidence supporting the distinctness of the Pertucinogena clade, we are proposing transfer of species from this clade into a novel genus gen. nov. also branches outside of the main cluster and groups reliably with and . Six identified CSIs are uniquely shared by these three species and we are proposing their integration into the emended genus , which has priority over the name . We are also proposing transfer of the deep-branching , for which 22 exclusive CSIs have been identified, into the genus gen. nov. Lastly, we present strong evidence that the species and are misclassified into the genus and that they are specifically related to the genera and , respectively. In addition, we are also reclassifying ' as sp. nov. (Type strain: G-6302=ATCC 31363=BCRC 13035).
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Genomics; Phylogeny; Pseudomonadaceae; Pseudomonas; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Xanthomonas
PubMed: 34546867
DOI: 10.1099/ijsem.0.005011 -
MSystems Feb 2023A major source of pseudomonad-specialized metabolites is the nonribosomal peptide synthetases (NRPSs) assembling siderophores and lipopeptides. Cyclic lipopeptides...
A major source of pseudomonad-specialized metabolites is the nonribosomal peptide synthetases (NRPSs) assembling siderophores and lipopeptides. Cyclic lipopeptides (CLPs) of the Mycin and Peptin families are frequently associated with, but not restricted to, phytopathogenic species. We conducted an analysis of the NRPSs encoded by lipopeptide biosynthetic gene clusters in nonpathogenic Pseudomonas genomes, covering 13 chemically diversified families. This global assessment of lipopeptide production capacity revealed it to be confined to the Pseudomonas fluorescens lineage, with most strains synthesizing a single type of CLP. Whereas certain lipopeptide families are specific for a taxonomic subgroup, others are found in distant groups. NRPS activation domain-guided peptide predictions enabled reliable family assignments, including identification of novel members. Focusing on the two most abundant lipopeptide families (Viscosin and Amphisin), a portion of their uncharted diversity was mapped, including characterization of two novel Amphisin family members (nepenthesin and oakridgin). Using NMR fingerprint matching, known Viscosin-family lipopeptides were identified in 15 (type) species spread across different taxonomic groups. A bifurcate genomic organization predominates among Viscosin-family producers and typifies Xantholysin-, Entolysin-, and Poaeamide-family producers but most families feature a single NRPS gene cluster embedded between cognate regulator and transporter genes. The strong correlation observed between NRPS system phylogeny and -based taxonomic affiliation indicates that much of the structural diversity is linked to speciation, providing few indications of horizontal gene transfer. The grouping of most NRPS systems in four superfamilies based on activation domain homology suggests extensive module dynamics driven by domain deletions, duplications, and exchanges. Pseudomonas species are prominent producers of lipopeptides that support proliferation in a multitude of environments and foster varied lifestyles. By genome mining of biosynthetic gene clusters (BGCs) with lipopeptide-specific organization, we mapped the global Pseudomonas lipopeptidome and linked its staggering diversity to taxonomy of the producers, belonging to different groups within the major Pseudomonas fluorescens lineage. Activation domain phylogeny of newly mined lipopeptide synthetases combined with previously characterized enzymes enabled assignment of predicted BGC products to specific lipopeptide families. In addition, novel peptide sequences were detected, showing the value of substrate specificity analysis for prioritization of BGCs for further characterization. NMR fingerprint matching proved an excellent tool to unequivocally identify multiple lipopeptides bioinformatically assigned to the Viscosin family, by far the most abundant one in Pseudomonas and with stereochemistry of all its current members elucidated. In-depth analysis of activation domains provided insight into mechanisms driving lipopeptide structural diversification.
Topics: Pseudomonas; Pseudomonas fluorescens; Lipopeptides; Phylogeny
PubMed: 36719227
DOI: 10.1128/msystems.00988-22 -
Toxins Sep 2020is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified as a critical agent... (Review)
Review
is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified as a critical agent threatening human health, and for which the development of new treatments is urgently necessary. One interesting avenue is to target virulence factors to understand pathogenicity. Thus, characterising exoproteins of is a hot research topic and proteomics is a powerful approach that provides important information to gain insights on bacterial virulence. The aim of this review is to focus on the contribution of proteomics to the studies of exoproteins, highlighting its relevance in the discovery of virulence factors, post-translational modifications on exoproteins and host-pathogen relationships.
Topics: Bacterial Proteins; Host-Pathogen Interactions; Protein Processing, Post-Translational; Proteome; Proteomics; Pseudomonas aeruginosa; Virulence; Virulence Factors
PubMed: 32899849
DOI: 10.3390/toxins12090571 -
Archives of Microbiology Jul 2021Insects and bacteria are the most widespread groups of organisms found in nearly all habitats on earth, establishing diverse interactions that encompass the entire range... (Review)
Review
Insects and bacteria are the most widespread groups of organisms found in nearly all habitats on earth, establishing diverse interactions that encompass the entire range of possible symbiotic associations from strict parasitism to obligate mutualism. The complexity of their interactions is instrumental in shaping the roles of insects in the environment, meanwhile ensuring the survival and persistence of the associated bacteria. This review aims to provide detailed insight on the multifaceted symbiosis between one of the most versatile bacterial genera, Pseudomonas (Gammaproteobacteria: Pseudomonadaceae) and a diverse group of insect species. The Pseudomonas engages with varied interactions with insects, being either a pathogen or beneficial endosymbiont, as well as using insects as vectors. In addition, this review also provides updates on existing and potential applications of Pseudomonas and their numerous insecticidal metabolites as biocontrol agents against pest insects for the improvement of integrated pest management strategies. Here, we have summarized several known modes of action and the virulence factors of entomopathogenic Pseudomonas strains essential for their pathogenicity against insects. Meanwhile, the beneficial interactions between pseudomonads and insects are currently limited to a few known insect taxa, despite numerous studies reporting identification of pseudomonads in the guts and haemocoel of various insect species. The vector-symbiont association between pseudomonads and insects can be diverse from strict phoresy to a role switch from commensalism to parasitism following a dose-dependent response. Overall, the pseudomonads appeared to have evolved independently to be either exclusively pathogenic or beneficial towards insects.
Topics: Animals; Biological Control Agents; Host-Pathogen Interactions; Insect Vectors; Insecta; Pseudomonas; Symbiosis; Virulence Factors
PubMed: 33634321
DOI: 10.1007/s00203-021-02230-9 -
Current Opinion in Microbiology Feb 2020Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious... (Review)
Review
Chronic infections often contain complex polymicrobial communities that are recalcitrant to antibiotic treatment. The pathogens associated with these infectious communities are often studied in pure culture for their ability to cause disease. However, recent studies have begun to focus on the role of polymicrobial interactions in disease outcomes. Pseudomonas aeruginosa can colonize patients with chronic lung diseases for years and sometimes even decades. During these prolonged infections, P. aeruginosa encounters a plethora of other microbes including bacteria, fungi, and viruses. The interactions between these microbes can vary greatly, ranging from antagonistic to synergistic depending on specific host and microbe-associated contexts. These additional layers of complexity associated with chronic P. aeruginosa infections must be considered in future studies in order to fully understand the physiology of infection. Such studies focusing on the entire infectious community rather than individual species may ultimately lead to more effective therapeutic design for persistent polymicrobial infections.
Topics: Animals; Bacteria; Humans; Lung; Lung Diseases; Microbial Interactions; Microbiota; Pseudomonas aeruginosa
PubMed: 32062024
DOI: 10.1016/j.mib.2020.01.014 -
Microbial Cell Factories Mar 2021Rhamnolipids have recently attracted considerable attentions because of their excellent biosurfactant performance and potential applications in agriculture, environment,... (Review)
Review
Rhamnolipids have recently attracted considerable attentions because of their excellent biosurfactant performance and potential applications in agriculture, environment, biomedicine, etc., but severe foaming causes the high cost of production, restraining their commercial production and applications. To reduce or eliminate the foaming, numerous explorations have been focused on foaming factors and fermentation strategies, but a systematic summary and discussion are still lacking. Additionally, although these studies have not broken through the bottleneck of foaming, they are conducive to understanding the foaming mechanism and developing more effective rhamnolipids production strategies. Therefore, this review focuses on the effects of fermentation components and control conditions on foaming behavior and fermentation strategies responded to the severe foaming in rhamnolipids fermentation and systematically summarizes 6 impact factors and 9 fermentation strategies. Furthermore, the potentialities of 9 fermentation strategies for large-scale production are discussed and some further strategies are suggested. We hope this review can further facilitate the understanding of foaming factors and fermentation strategies as well as conducive to developing the more effective large-scale production strategies to accelerate the commercial production process of rhamnolipids.
Topics: Fermentation; Glycolipids; Industrial Microbiology; Pseudomonas aeruginosa; Surface-Active Agents
PubMed: 33781264
DOI: 10.1186/s12934-021-01516-3 -
Environmental Microbiology Dec 2019Pseudomonas syringae is a model phytopathogenic bacterium that uses the type III secretion system (T3SS) to cause lethal diseases in staple crops and thus presents a... (Review)
Review
Pseudomonas syringae is a model phytopathogenic bacterium that uses the type III secretion system (T3SS) to cause lethal diseases in staple crops and thus presents a threat to food security worldwide. Great progress has been made in delineating the biochemical mechanisms and cellular targets of T3SS effectors, but less is known about the signalling pathways and molecular mechanisms of T3SS regulators. In recent years, thanks to the popularity and power of genome-wide mutant screening and high-throughput sequencing, new regulatory proteins (such as RhpR, AefR, AlgU and CvsR) and proteases (such as Lon and RhpP) have been identified as T3SS regulators in P. syringae pathovars. The detailed mechanisms of previously illustrated regulators (such as HrpRS, HrpL and HrpGV) have also been further studied. Notably, the two-component system RhpRS has been determined to play key roles in the modulation of T3SS via direct regulation of hrpRS and other virulence-related pathways by sensing changes in environmental signals. In addition, secondary messengers (such as c-di-GMP and ppGpp) have been shown to fine-tune the activity of T3SS. Overall, these studies have suggested the existence of a highly intricate regulatory network for T3SS, which controls the pathogenicity of P. syringae. This short review summarizes studies of P. syringae T3SS regulation and the known mechanisms of key regulators.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Pseudomonas syringae; Transcription Factors; Type III Secretion Systems; Virulence
PubMed: 31408268
DOI: 10.1111/1462-2920.14779 -
Nature Reviews. Chemistry Jun 2023
Topics: Nitrogenase; Azotobacter vinelandii
PubMed: 37237160
DOI: 10.1038/s41570-023-00507-9