-
Nucleic Acids Research Mar 2020Tight and coordinate regulation of virulence determinants is essential for bacterial biology and involves dynamic shaping of transcriptional regulatory networks during...
Tight and coordinate regulation of virulence determinants is essential for bacterial biology and involves dynamic shaping of transcriptional regulatory networks during evolution. The horizontally transferred two-partner secretion system ExlB-ExlA is instrumental in the virulence of different Pseudomonas species, ranging from soil- and plant-dwelling biocontrol agents to the major human pathogen Pseudomonas aeruginosa. Here, we identify a Cro/CI-like repressor, named ErfA, which together with Vfr, a CRP-like activator, controls exlBA expression in P. aeruginosa. The characterization of ErfA regulon across P. aeruginosa subfamilies revealed a second conserved target, the ergAB operon, with functions unrelated to virulence. To gain insights into this functional dichotomy, we defined the pan-regulon of ErfA in several Pseudomonas species and found ergAB as the sole conserved target of ErfA. The analysis of 446 exlBA promoter sequences from all exlBA+ genomes revealed a wide variety of regulatory sequences, as ErfA- and Vfr-binding sites were found to have evolved specifically in P. aeruginosa and nearly each species carries different regulatory sequences for this operon. We propose that the emergence of different regulatory cis-elements in the promoters of horizontally transferred genes is an example of plasticity of regulatory networks evolving to provide an adapted response in each individual niche.
Topics: A549 Cells; Bacterial Proteins; Bacterial Toxins; Base Sequence; Gene Expression Regulation, Bacterial; Humans; Operon; Promoter Regions, Genetic; Protein Binding; Pseudomonas; Repressor Proteins; Species Specificity; Transcription Factors; Virulence
PubMed: 31925438
DOI: 10.1093/nar/gkz1232 -
Applied and Environmental Microbiology Mar 2021Perturbation of natural microbial communities by antimicrobials, such as triclosan, can result in selection for antibiotic tolerance, which is of particular concern when...
Perturbation of natural microbial communities by antimicrobials, such as triclosan, can result in selection for antibiotic tolerance, which is of particular concern when pathogens are present. Members of the genus are found in many natural microbial communities and frequently demonstrate increased abundance following triclosan exposure. The pathogen and well-studied model organism exhibits high triclosan tolerance; however, it is unknown if all species share this trait or if there are susceptible strains. We characterized the triclosan tolerance phenotypes of diverse isolates obtained from triclosan-exposed built environments and identified both tolerant and sensitive strains. High tolerance is associated with carriage of the enoyl-acyl carrier reductase (ENR) isozyme gene , compared to the lesser protective effects of efflux or presence of ENRs. Given its unique importance, we examined distribution throughout species using large-scale phylogenomic analyses. We find presence or absence is largely invariant at the species level but demonstrates multiple gain and loss events in its evolutionary history. We further provide evidence of its presence on mobile genetic elements. Our results demonstrate the surprising variability in triclosan tolerance in and confirm to be a useful indicator for high triclosan tolerance in These findings provide a framework for better monitoring of in triclosan-exposed environments and interpreting effects on species and gene composition. Closely related species are typically assumed to demonstrate similar phenotypes driven by underlying conserved genotypes. When monitoring for the effect of antimicrobials on the types of species that may be selected for, this assumption may prove to be incorrect, and identification of additional genetic markers may be necessary. We isolated several phylogenetically diverse members of from indoor environments and tested their phenotypic tolerance toward the commonly used antimicrobial triclosan. Although isolates are broadly regarded to be highly triclosan tolerant, we demonstrate the presence of both triclosan-tolerant and -susceptible strains, separated by a difference in tolerance of nearly 3 orders of magnitude. Bioinformatic and experimental investigation demonstrated that the presence of the gene was associated with high tolerance. We demonstrate that is not evenly distributed in all species and that its presence could be a useful predictor of high triclosan tolerance suitable for antimicrobial monitoring efforts involving triclosan.
Topics: Anti-Bacterial Agents; Anti-Infective Agents, Local; Drug Resistance, Bacterial; Pseudomonas; Species Specificity; Triclosan
PubMed: 33483311
DOI: 10.1128/AEM.02924-20 -
Scientific Reports Feb 2022Lactic acid is an important platform chemical used for the production of various compounds including polylactic acid (PLA). Optically pure L- and D-lactic acids are...
Lactic acid is an important platform chemical used for the production of various compounds including polylactic acid (PLA). Optically pure L- and D-lactic acids are required to obtain high quality PLA. To advance the development and selection of microbial strains for improved production of lactic acid enantiomers, a high-throughput screening, dynamic pathway control, or real-time monitoring are often applied. Inducible gene expression systems and their application in the genetically encoded biosensors contribute to the development of these techniques and are important devices for the advancement of lactic acid biotechnology. Here, we identify and characterize eleven lactate-inducible systems from Escherichia coli, Cupriavidus necator, and Pseudomonas spp. The specificity and dynamics of these systems in response to L- and D-lactate, or structurally similar compounds are investigated. We demonstrate that the inducible systems EcLldR/P and CnGntR/P respond only to the L-lactate, exhibiting approximately 19- and 24-fold induction, respectively. Despite neither of the examined bacteria possess the D-lactate-specific inducible system, the PaPdhR/P and PfPdhR/P are induced approximately 37- and 366-fold, respectively, by D-lactate and can be used for developing biosensor with improved specificity. The findings of this study provide an insight into understanding of L- and D-lactate-inducible systems that can be employed as sensing and tuneable devices in synthetic biology.
Topics: Biosensing Techniques; Cupriavidus necator; Escherichia coli; Lactic Acid; Multigene Family; Pseudomonas; Synthetic Biology
PubMed: 35136142
DOI: 10.1038/s41598-022-06028-7 -
Molecules (Basel, Switzerland) Feb 2023Phenazines are a large group of heterocyclic nitrogen-containing compounds with demonstrated insecticidal, antimicrobial, antiparasitic, and anticancer activities. These... (Review)
Review
Phenazines are a large group of heterocyclic nitrogen-containing compounds with demonstrated insecticidal, antimicrobial, antiparasitic, and anticancer activities. These natural compounds are synthesized by several microorganisms originating from diverse habitats, including marine and terrestrial sources. The most well-studied producers belong to the genus, which has been extensively investigated over the years for its ability to synthesize phenazines. This review is focused on the research performed on pseudomonads' phenazines in recent years. Their biosynthetic pathways, mechanism of regulation, production processes, bioactivities, and applications are revised in this manuscript.
Topics: Pseudomonas; Phenazines; Ecosystem; Biosynthetic Pathways
PubMed: 36771036
DOI: 10.3390/molecules28031368 -
Japanese Journal of Infectious Diseases Nov 2022Monomicrobial necrotizing fasciitis caused by Pseudomonas species is a rare infection. This study aimed to elucidate the specific characteristics and clinical outcomes...
Monomicrobial necrotizing fasciitis caused by Pseudomonas species is a rare infection. This study aimed to elucidate the specific characteristics and clinical outcomes of necrotizing fasciitis caused by Pseudomonas aeruginosa and Pseudomonas fluorescens. Ten patients with monomicrobial necrotizing fasciitis caused by Pseudomonas species were retrospectively reviewed in an 8-year period. Differences in mortality, patient characteristics, clinical presentation, laboratory data, and clinical outcomes were compared between the death and survival groups. Two patients died, showing a mortality rate of 20%. P. aeruginosa was the causative agent in nine patients and P. fluorescens in one patient. The most common comorbidity was type 2 diabetes (n = 5). We found that patients who died had lower albumin levels and higher leukocyte counts than those who survived. Monomicrobial necrotizing fasciitis caused by Pseudomonas species needs emergent surgical intervention and aggressive intensive care due to the high mortality rate. We report the first case of monomicrobial necrotizing fasciitis caused by P. fluorescens. Severe hypoalbuminemia and high leukocyte counts in initial laboratory examinations can be considered poor prognostic factors.
Topics: Humans; Fasciitis, Necrotizing; Pseudomonas aeruginosa; Pseudomonas fluorescens; Retrospective Studies; Diabetes Mellitus, Type 2; Sepsis
PubMed: 35908872
DOI: 10.7883/yoken.JJID.2022.087 -
Brazilian Journal of Biology = Revista... 2021The effects of Calcium (Ca+2) on virulence and some parameters should be analyzed in this study. Pseudomonas aeruginosa Gram (-) and Bacillus cereus Gram (+) were used....
The effects of Calcium (Ca+2) on virulence and some parameters should be analyzed in this study. Pseudomonas aeruginosa Gram (-) and Bacillus cereus Gram (+) were used. Both bacteria are soil bacteria. In this study; the effect of Ca+2 on protease, amylase, LasB elastolytic assay, H2O2, pyorubin and biofilm on metabolites of these bacteria were investigated during 24 hour time. In this study, the effect of Ca+2 on the production of some secondary metabolites on P. aeruginosa and B. cereus was investigated and presented for the first time by us.
Topics: Bacillus cereus; Calcium; Hydrogen Peroxide; Pseudomonas; Pseudomonas aeruginosa
PubMed: 34133571
DOI: 10.1590/1519-6984.243189 -
Applied and Environmental Microbiology Oct 2021Bacteria rapidly adapt to their environment by integrating external stimuli through diverse signal transduction systems. Pseudomonas aeruginosa, for example, senses...
Bacteria rapidly adapt to their environment by integrating external stimuli through diverse signal transduction systems. Pseudomonas aeruginosa, for example, senses surface contact through the Wsp signal transduction system to trigger the production of cyclic di-GMP. Diverse mutations in genes that manifest enhanced biofilm formation are frequently reported in clinical isolates of P. aeruginosa and in biofilm studies of Pseudomonas spp. and Burkholderia cenocepacia. In contrast to the convergent phenotypes associated with comparable mutations, we demonstrate that the Wsp system in B. cenocepacia does not impact intracellular cyclic di-GMP levels, unlike that in Pseudomonas spp. Our current mechanistic understanding of the Wsp system is based entirely on the study of four Pseudomonas spp., and its phylogenetic distribution remains unknown. Here, we present a broad phylogenetic analysis to show that the Wsp system originated in the betaproteobacteria and then horizontally transferred to Pseudomonas spp., the sole member of the gammaproteobacteria. Alignment of 794 independent Wsp systems with reported mutations from the literature identified key amino acid residues that fall within and outside annotated functional domains. Specific residues that are highly conserved but uniquely modified in B. cenocepacia likely define mechanistic differences among Wsp systems. We also find the greatest sequence variation in the extracellular sensory domain of WspA, indicating potential adaptations to diverse external stimuli beyond surface contact sensing. This study emphasizes the need to better understand the breadth of functional diversity of the Wsp system as a major regulator of bacterial adaptation beyond B. cenocepacia and select Pseudomonas spp. The Wsp signal transduction system serves as an important model system for studying how bacteria adapt to living in densely structured communities known as biofilms. Biofilms frequently cause chronic infections and environmental fouling, and they are very difficult to eradicate. In Pseudomonas aeruginosa, the Wsp system senses contact with a surface, which in turn activates specific genes that promote biofilm formation. We demonstrate that the Wsp system in Burkholderia cenocepacia regulates biofilm formation uniquely from that in Pseudomonas species. Furthermore, a broad phylogenetic analysis reveals the presence of the Wsp system in diverse bacterial species, and sequence analyses of 794 independent systems suggest that the core signaling components function similarly but with key differences that may alter what or how they sense. This study shows that Wsp systems are highly conserved and more broadly distributed than previously thought, and their unique differences likely reflect adaptations to distinct environments.
Topics: Betaproteobacteria; Biological Evolution; Gammaproteobacteria; Phylogeny; Pseudomonas; Signal Transduction
PubMed: 34495711
DOI: 10.1128/AEM.01306-21 -
Frontiers in Cellular and Infection... 2021Bacterial biofilms are important medically, environmentally and industrially and there is a need to understand the processes that govern functional synergy and dynamics...
Bacterial biofilms are important medically, environmentally and industrially and there is a need to understand the processes that govern functional synergy and dynamics of species within biofilm communities. Here, we have used a model, mixed-species biofilm community comprised of PAO1, Pf-5 and KP1. This biofilm community displays higher biomass and increased resilience to antimicrobial stress conditions such as sodium dodecyl sulfate and tobramycin, compared to monospecies biofilm populations. is present at low proportions in the community and yet, it plays a critical role in community function, suggesting it acts as a keystone species in this community. To determine the factors that regulate community composition, we focused on because of its pronounced impact on community structure and function. Specifically, we evaluated the role of the N-acyl homoserine lactone (AHL) dependent quorum sensing (QS) system of PAO1, which regulates group behaviors including biofilm formation and the production of effector molecules. We found that mixed species biofilms containing QS mutants had significantly altered proportions of and populations compared to mixed species biofilms with the wild type . Similarly, inactivation of QS effector genes, e.g. and , also governed the relative species proportions. While the absence of QS did not alter the proportions of the two species in dual species biofilms of and , it resulted in significantly lower proportions of in dual species biofilms with . These observations suggest that QS plays an important role in modulating community biofilm structure and physiology and affects interspecific interactions.
Topics: Acyl-Butyrolactones; Biofilms; Pseudomonas; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 33869078
DOI: 10.3389/fcimb.2021.646991 -
Clinical Microbiology and Infection :... Mar 2021This study aims to investigate ampicillin catabolism in a pandrug-resistant strain, Pseudomonas sp. MR 02 of P. putida lineage.
OBJECTIVES
This study aims to investigate ampicillin catabolism in a pandrug-resistant strain, Pseudomonas sp. MR 02 of P. putida lineage.
METHODS
The characterization of carbapenem resistance was done following the standard protocol. The broth macrodilution method was used to determine the MIC values of antimicrobial agents both in the presence and in the absence of phenylalanine-β-naphthylamide. High MIC values (>10 000 mg/L) of ampicillin led to speculation that it may serve as a growth substrate, and thus minimal medium was used to evaluate ampicillin as a nutrient. The growth of MR 02 was measured in minimal medium in the presence or absence of 0.4 mM EDTA, supplemented with ampicillin as sole carbon, nitrogen and energy source. RNA-seq was used to generate expression profiles of genes in ampicillin or glucose-grown cells. The bla gene of MR 02 was cloned in the pHSG398 vector and expressed in Escherichia coli DH5α.
RESULTS
Phenotypic analysis along with genome sequence data identifies Pseudomonas sp. MR 02 as a pandrug-resistant strain. Transcriptome data has revealed that bla was among the top 50 differentially expressed genes in ampicillin grown cells compared to the glucose grown cells in the minimal medium. Heterologous expression of bla gene in E. coli DH5α enabled its growth and subsistence on ampicillin as the sole source of carbon and energy.
DISCUSSION
The ability of a pandrug-resistant Pseudomonas sp. MR 02 to consume ampicillin for growth has a huge implication in the bioremediation of β-lactam residues in the environment.
Topics: Ampicillin; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Microbial Sensitivity Tests; Pseudomonas; beta-Lactamases
PubMed: 33160034
DOI: 10.1016/j.cmi.2020.10.032 -
The biotechnological potential of marine bacteria in the novel lineage of Pseudomonas pertucinogena.Microbial Biotechnology Jan 2020Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully... (Review)
Review
Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully exploited for industrial applications. Recently, a group of Pseudomonas species isolated from extreme habitats or living in association with algae or sponges were clustered in the newly established Pseudomonas pertucinogena lineage. Remarkably for the predominantly terrestrial genus Pseudomonas, more than half (9) of currently 16 species within this lineage were isolated from marine or saline habitats. Unlike other Pseudomonas species, they seem to have in common a highly specialized metabolism. Furthermore, the marine members apparently possess the capacity to produce biomolecules of biotechnological interest (e.g. dehalogenases, polyester hydrolases, transaminases). Here, we summarize the knowledge regarding the enzymatic endowment of the marine Pseudomonas pertucinogena bacteria and report on a genomic analysis focusing on the presence of genes encoding esterases, dehalogenases, transaminases and secondary metabolites including carbon storage compounds.
Topics: Bacteria; Biotechnology; Ecosystem; Pseudomonas
PubMed: 29943398
DOI: 10.1111/1751-7915.13288