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Beaussart A, Paiva TO, Geiger CJ, Baker AE, O'Toole GA, Dufrêne YF. Atomic force microscopy analysis of Pel polysaccharide- and type IV pili-mediated adhesion of Pseudomonas aeruginosa PA14 to an abiotic surface. NANOSCALE 2024; 16:12134-12141. [PMID: 38832761 DOI: 10.1039/d4nr01415d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Type IV pili (TFP) contribute to the ability of microbes such as Pseudomonas aeruginosa to engage with and move across surfaces. We reported previously that P. aeruginosa TFP generate retractive forces of ∼30 pN and provided indirect evidence that TFP-mediated surface attachment was enhanced in the presence of the Pel polysaccharide. Here, we use different mutants defective in flagellar, Pel production or TFP production - alone or in combination - to decipher the relative contribution of these biofilm-promoting factors for P. aeruginosa adhesion. By means of atomic force microscopy (AFM), we show that mutating the flagellum (ΔflgK mutant) results in an increase in Pel polysaccharide production, but this increase in Pel does not result in an increase in surface adhesive properties compared to those previously described for the WT strain. By blocking Pel production in the ΔflgK mutant (ΔflgKΔpel), we directly show that TFP play a major role in the adhesion of the bacteria to hydrophobic AFM tips, but that the adhesion force is only slightly impaired by the absence of Pel. Inversely, performing single-cell force spectroscopy measurements with the mutant lacking TFP (ΔflgKΔpilA) reveals that the Pel can modulate the attachment of the bacteria to a hydrophobic substrate in a time-dependent manner. Finally, little adhesion was detected for the ΔflgKΔpilAΔpelA triple mutant, suggesting that both TFP and Pel polysaccharide make a substantial contribution to bacteria-substratum interaction events. Altogether, our data allow us to decipher the relative contribution of Pel and TFP in the early attachment by P. aeruginosa.
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Affiliation(s)
- Audrey Beaussart
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
| | - Telmo O Paiva
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
| | - Christopher J Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - Amy E Baker
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
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2
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Benyamini P. Phylogenetic Tracing of Evolutionarily Conserved Zonula Occludens Toxin Reveals a "High Value" Vaccine Candidate Specific for Treating Multi-Strain Pseudomonas aeruginosa Infections. Toxins (Basel) 2024; 16:271. [PMID: 38922165 PMCID: PMC11209546 DOI: 10.3390/toxins16060271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/09/2024] [Accepted: 06/12/2024] [Indexed: 06/27/2024] Open
Abstract
Extensively drug-resistant Pseudomonas aeruginosa infections are emerging as a significant threat associated with adverse patient outcomes. Due to this organism's inherent properties of developing antibiotic resistance, we sought to investigate alternative strategies such as identifying "high value" antigens for immunotherapy-based purposes. Through extensive database mining, we discovered that numerous Gram-negative bacterial (GNB) genomes, many of which are known multidrug-resistant (MDR) pathogens, including P. aeruginosa, horizontally acquired the evolutionarily conserved gene encoding Zonula occludens toxin (Zot) with a substantial degree of homology. The toxin's genomic footprint among so many different GNB stresses its evolutionary importance. By employing in silico techniques such as proteomic-based phylogenetic tracing, in conjunction with comparative structural modeling, we discovered a highly conserved intermembrane associated stretch of 70 amino acids shared among all the GNB strains analyzed. The characterization of our newly identified antigen reveals it to be a "high value" vaccine candidate specific for P. aeruginosa. This newly identified antigen harbors multiple non-overlapping B- and T-cell epitopes exhibiting very high binding affinities and can adopt identical tertiary structures among the least genetically homologous P. aeruginosa strains. Taken together, using proteomic-driven reverse vaccinology techniques, we identified multiple "high value" vaccine candidates capable of eliciting a polarized immune response against all the P. aeruginosa genetic variants tested.
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Affiliation(s)
- Payam Benyamini
- Department of Health Sciences at Extension, University of California Los Angeles, 1145 Gayley Ave., Los Angeles, CA 90024, USA
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3
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Hausmann S, Geiser J, Allen GE, Geslain SAM, Valentini M. Intrinsically disordered regions regulate RhlE RNA helicase functions in bacteria. Nucleic Acids Res 2024:gkae511. [PMID: 38874491 DOI: 10.1093/nar/gkae511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 05/29/2024] [Accepted: 06/03/2024] [Indexed: 06/15/2024] Open
Abstract
RNA helicases-central enzymes in RNA metabolism-often feature intrinsically disordered regions (IDRs) that enable phase separation and complex molecular interactions. In the bacterial pathogen Pseudomonas aeruginosa, the non-redundant RhlE1 and RhlE2 RNA helicases share a conserved REC catalytic core but differ in C-terminal IDRs. Here, we show how the IDR diversity defines RhlE RNA helicase specificity of function. Both IDRs facilitate RNA binding and phase separation, localizing proteins in cytoplasmic clusters. However, RhlE2 IDR is more efficient in enhancing REC core RNA unwinding, exhibits a greater tendency for phase separation, and interacts with the RNase E endonuclease, a crucial player in mRNA degradation. Swapping IDRs results in chimeric proteins that are biochemically active but functionally distinct as compared to their native counterparts. The RECRhlE1-IDRRhlE2 chimera improves cold growth of a rhlE1 mutant, gains interaction with RNase E and affects a subset of both RhlE1 and RhlE2 RNA targets. The RECRhlE2-IDRRhlE1 chimera instead hampers bacterial growth at low temperatures in the absence of RhlE1, with its detrimental effect linked to aberrant RNA droplets. By showing that IDRs modulate both protein core activities and subcellular localization, our study defines the impact of IDR diversity on the functional differentiation of RNA helicases.
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Affiliation(s)
- Stéphane Hausmann
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Johan Geiser
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - George Edward Allen
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Sandra Amandine Marie Geslain
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Martina Valentini
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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4
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Geiger CJ, Wong GCL, O'Toole GA. A bacterial sense of touch: T4P retraction motor as a means of surface sensing by Pseudomonas aeruginosa PA14. J Bacteriol 2024:e0044223. [PMID: 38832786 DOI: 10.1128/jb.00442-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Most microbial cells found in nature exist in matrix-covered, surface-attached communities known as biofilms. This mode of growth is initiated by the ability of the microbe to sense a surface on which to grow. The opportunistic pathogen Pseudomonas aeruginosa (Pa) PA14 utilizes a single polar flagellum and type 4 pili (T4P) to sense surfaces. For Pa, T4P-dependent "twitching" motility is characterized by effectively pulling the cell across a surface through a complex process of cooperative binding, pulling, and unbinding. T4P retraction is powered by hexameric ATPases. Pa cells that have engaged a surface increase production of the second messenger cyclic AMP (cAMP) over multiple generations via the Pil-Chp system. This rise in cAMP allows cells and their progeny to become better adapted for surface attachment and activates virulence pathways through the cAMP-binding transcription factor Vfr. While many studies have focused on mechanisms of T4P twitching and regulation of T4P production and function by the Pil-Chp system, the mechanism by which Pa senses and relays a surface-engagement signal to the cell is still an open question. Here we review the current state of the surface sensing literature for Pa, with a focus on T4P, and propose an integrated model of surface sensing whereby the retraction motor PilT senses and relays the signal to the Pil-Chp system via PilJ to drive cAMP production and adaptation to a surface lifestyle.
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Affiliation(s)
- C J Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - G C L Wong
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - G A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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5
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Tabassum N, Jeong GJ, Jo DM, Khan F, Kim YM. Attenuation of biofilm and virulence factors of Pseudomonas aeruginosa by tetramethylpyrazine-gold nanoparticles. Microb Pathog 2024; 191:106658. [PMID: 38643850 DOI: 10.1016/j.micpath.2024.106658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/15/2024] [Accepted: 04/18/2024] [Indexed: 04/23/2024]
Abstract
Pseudomonas aeruginosa is often identified as the causative agent in nosocomial infections. Their adapted resistance makes them strong towards antimicrobial treatments. They protect and empower their survival behind strong biofilm architecture that works as their armor toward antimicrobial therapy. Additionally, P. aeruginosa generates virulence factors, contributing to chronic infection and recalcitrant phenotypic characteristics. The current study utilizes the benevolence of nanotechnology to develop an alternate technique to control the spreading of P. aeruginosa by limiting its biofilm and virulence development. This study used a natural compound, tetramethylpyrazine, to generate gold nanoparticles. Tetramethylpyrazine-gold nanoparticles (Tet-AuNPs) were presented in spherical shapes, with an average size of 168 ± 52.49 nm and a zeta potential of -12.22 ± 2.06 mV. The minimum inhibition concentration (MIC) of Tet-AuNPs that proved more than 90 % effective in inhibiting P. aeruginosa was 256 μg/mL. Additionally, it also shows antibacterial activities against Staphylococcus aureus (MIC, 256 μg/mL), Streptococcus mutans (MIC, 128 μg/mL), Klebsiella pneumoniae (MIC, 128 μg/mL), Listeria monocytogenes (MIC, 256 μg/mL), and Escherichia coli (MIC, 256 μg/mL). The sub-MIC values of Tet-AuNPs significantly inhibited the early-stage biofilm formation of P. aeruginosa. Moreover, this concentration strongly affected hemolysis, protease activity, and different forms of motilities in P. aeruginosa. Additionally, Tet-AuNPs destroyed the well-established mature biofilm of P. aeruginosa. The expression of genes linked with the biofilm formation and virulence in P. aeruginosa treated with sub-MIC doses of Tet-AuNPs was shown to be significantly suppressed. Gene expression studies support biofilm- and virulence-suppressing effects of Tet-AuNPs at the phenotypic level.
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Affiliation(s)
- Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Geum-Jae Jeong
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea; Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Du-Min Jo
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea; National Marine Biodiversity Institute of Korea, Seochun, Chungcheongnam-do, 33662, Republic of Korea
| | - Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea; Institute of Fisheries Science, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Young-Mog Kim
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea; Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea; Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
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6
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Wang C, Ma Q, Zhang J, Meng N, Xu D. Co-culture of benzalkonium chloride promotes the biofilm formation and decreases the antibiotic susceptibility of a Pseudomonas aeruginosa strain. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:858-869. [PMID: 38687259 DOI: 10.1039/d4em00035h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Benzalkonium chloride (BAC) is a disinfectant with broad-spectrum antibacterial properties, yet despite its widespread use and detection in the environment, the effects of BAC exposure on microorganisms remain poorly documented. Herein, the impacts of BAC on a Pseudomonas aeruginosa strain Jade-X were systematically investigated. The results demonstrated that the minimum inhibitory concentration (MIC) of BAC against strain Jade-X was 64 mg L-1. Exposure to BAC concentrations of 8, 16, 32, and 64 mg L-1 significantly augmented biofilm formation by 2.03-, 2.43-, 2.96-, and 2.56-fold respectively. The swimming and twitching abilities, along with the virulence factor production, were inhibited. Consistently, quantitative reverse transcription PCR assays revealed significant downregulation of genes related to flagellate- and pili-mediated motilities (flgD, flgE, pilB, pilQ, and motB), as well as phzA and phzB genes involved in pyocyanin production. The results of disk diffusion and MIC assays demonstrated that BAC decreased the antibiotic susceptibility of ciprofloxacin, levofloxacin, norfloxacin, and tetracycline. Conversely, an opposite trend was observed for polymyxin B and ceftriaxone. Genomic analysis revealed that strain Jade-X harbored eleven resistance-nodulation-cell division efflux pumps, with mexCD-oprJ exhibiting significant upregulation while mexEF-oprN and mexGHI-opmD were downregulated. In addition, the quorum sensing-related regulators LasR and RhlR were also suppressed, implying that BAC might modulate the physiological and biochemical behaviors of strain Jade-X by attenuating the quorum sensing system. This study enhances our understanding of interactions between BAC and P. aeruginosa, providing valuable insights to guide the regulation and rational use of BAC.
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Affiliation(s)
- Caihong Wang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
| | - Qiao Ma
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
| | - Jiaxin Zhang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
| | - Nan Meng
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
| | - Dan Xu
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
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7
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Xu Y, Liu Q, Wang B, Li Q, Chen Y, Yang Y, Zhu Z, Gong D, Zhang C, Wang G, Qian H. Tobramycin-mediated self-assembly of DNA nanostructures for targeted treatment of Pseudomonas aeruginosa-infected lung inflammation. Biomater Sci 2024; 12:2331-2340. [PMID: 38488889 DOI: 10.1039/d3bm02121a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Pseudomonas aeruginosa (PA) is one of the most common multidrug-resistant pathogens found in clinics, often manifesting as biofilms. However, due to the emergence of superbugs in hospitals and the overuse of antibiotics, the prevention and treatment of PA infections have become increasingly challenging. Utilizing DNA nanostructures for packaging and delivering antibiotics presents an intervention strategy with significant potential. Nevertheless, construction of functional DNA nanostructures with multiple functionalities and enhanced stability in physiological settings remains challenging. In this study, the authors propose a magnesium-free assembly method that utilizes tobramycin (Tob) as a mediator to assemble DNA nanostructures, allowing for the functionalization of DNA nanostructures by combining DNA and antibiotics. Additionally, our study incorporates maleimide-modified DNA into the nanostructures to act as a targeting moiety specifically directed towards the pili of PA. The targeting ability of the constructed functional DNA nanostructure significantly improves the local concentration of Tob, thereby reducing the side effects of antibiotics. Our results demonstrate the successful construction of a maleimide-decorated Tob/DNA nanotube (NTTob-Mal) for the treatment of PA-infected lung inflammation. The stability and biocompatibility of NTTob-Mal are confirmed, highlighting its potential for clinical applications. Furthermore, its specificity in recognizing and adhering to PA has been validated. In vitro experiments have shown its efficacy in inhibiting PA biofilm formation, and in a murine model, NTTob-Mal has exhibited significant therapeutic effectiveness against PA-induced pneumonia. In summary, the proposed antibiotic drug-mediated DNA nanostructure assembly approach holds promise as a novel strategy for targeted treatment of PA infections.
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Affiliation(s)
- Yuhang Xu
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Qian Liu
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
- Laboratory of Pharmacy and Chemistry, and Laboratory of Tissue and Cell Biology, Lab Teaching & Management Center, Chongqing Medical University, Chongqing, 400016, China
| | - Bin Wang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
- Chongqing Key Laboratory of Precision Medicine and Prevention of Major Respiratory Diseases, Chongqing 400037, China
| | - Quan Li
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Yue Chen
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Yao Yang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Zhihao Zhu
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Daohui Gong
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
| | - Chuan Zhang
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Guansong Wang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
- Chongqing Key Laboratory of Precision Medicine and Prevention of Major Respiratory Diseases, Chongqing 400037, China
| | - Hang Qian
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
- Chongqing Key Laboratory of Precision Medicine and Prevention of Major Respiratory Diseases, Chongqing 400037, China
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8
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Warrell DL, Zarrella TM, Machalek C, Khare A. Interspecies surfactants serve as public goods enabling surface motility in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.573969. [PMID: 38260674 PMCID: PMC10802355 DOI: 10.1101/2024.01.03.573969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
In most natural environments, bacteria live in polymicrobial communities where secreted molecules from neighboring species alter bacterial behaviors including motility, but such interactions are understudied. Pseudomonas aeruginosa is a motile opportunistic pathogen that exists in diverse multispecies environments such as the soil and is frequently found in human wound and respiratory tract co-infections with other bacteria including Staphylococcus aureus. Here we show that P. aeruginosa can co-opt secreted surfactants from other species for flagellar-based surface motility. We found that exogenous surfactants from S. aureus, other bacteria, and interkingdom species enabled P. aeruginosa to switch from swarming to an alternative surface spreading motility on semi-solid surfaces and allowed for the emergence of surface motility on hard agar where P. aeruginosa was otherwise unable to move. This motility was distinct from the response of other motile bacteria in the presence of exogenous surfactants. Mutant analysis indicated that this P. aeruginosa motility was similar to a previously described mucin-based motility, 'surfing', albeit with divergent regulation. Thus, our study demonstrates that secreted surfactants from the host as well as neighboring bacterial and interkingdom species act as public goods facilitating P. aeruginosa flagella-mediated surfing-like surface motility, thereby allowing it to access different environmental niches.
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Affiliation(s)
- Delayna L Warrell
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tiffany M Zarrella
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD, USA
- Current address: Department of Biology, Georgetown University, Washington, DC, USA
| | - Christopher Machalek
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Anupama Khare
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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9
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Thunes NC, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Gliding motility proteins GldJ and SprB contribute to Flavobacterium columnare virulence. J Bacteriol 2024; 206:e0006824. [PMID: 38517170 PMCID: PMC11025331 DOI: 10.1128/jb.00068-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024] Open
Abstract
Flavobacterium columnare causes columnaris disease in fish. Columnaris disease is incompletely understood, and adequate control measures are lacking. The type IX secretion system (T9SS) is required for F. columnare gliding motility and virulence. The T9SS and gliding motility machineries share some, but not all, components. GldN (required for gliding and for secretion) and PorV (involved in secretion but not required for gliding) are both needed for virulence, implicating T9SS-mediated secretion in virulence. The role of motility in virulence is uncertain. We constructed and analyzed sprB, sprF, and gldJ mutants that were defective for motility but that maintained T9SS function to understand the role of motility in virulence. Wild-type cells moved rapidly and formed spreading colonies. In contrast, sprB and sprF deletion mutants were partially defective in gliding and formed nonspreading colonies. Both mutants exhibited reduced virulence in rainbow trout fry. A gldJ deletion mutant was nonmotile, secretion deficient, and avirulent in rainbow trout fry. To separate the roles of GldJ in secretion and in motility, we generated gldJ truncation mutants that produce nearly full-length GldJ. Mutant gldJ563, which produces GldJ truncated at amino acid 563, was defective for gliding but was competent for secretion as measured by extracellular proteolytic activity. This mutant displayed reduced virulence in rainbow trout fry, suggesting that motility contributes to virulence. Fish that survived exposure to the sprB deletion mutant or the gldJ563 mutant exhibited partial resistance to later challenge with wild-type cells. The results aid our understanding of columnaris disease and may suggest control strategies.IMPORTANCEFlavobacterium columnare causes columnaris disease in many species of freshwater fish in the wild and in aquaculture systems. Fish mortalities resulting from columnaris disease are a major problem for aquaculture. F. columnare virulence is incompletely understood, and control measures are inadequate. Gliding motility and protein secretion have been suggested to contribute to columnaris disease, but evidence directly linking motility to disease was lacking. We isolated and analyzed mutants that were competent for secretion but defective for motility. Some of these mutants exhibited decreased virulence. Fish that had been exposed to these mutants were partially protected from later exposure to the wild type. The results contribute to our understanding of columnaris disease and may aid development of control strategies.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - David Pérez-Pascual
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Jean-Marc Ghigo
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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10
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Thongchol J, Yu Z, Harb L, Lin Y, Koch M, Theodore M, Narsaria U, Shaevitz J, Gitai Z, Wu Y, Zhang J, Zeng L. Removal of Pseudomonas type IV pili by a small RNA virus. Science 2024; 384:eadl0635. [PMID: 38574145 PMCID: PMC11126211 DOI: 10.1126/science.adl0635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/29/2024] [Indexed: 04/06/2024]
Abstract
The retractile type IV pilus (T4P) is important for virulence of the opportunistic human pathogen Pseudomonas aeruginosa. The single-stranded RNA (ssRNA) phage PP7 binds to T4P and is brought to the cell surface through pilus retraction. Using fluorescence microscopy, we discovered that PP7 detaches T4P, which impairs cell motility and restricts the pathogen's virulence. Using cryo-electron microscopy, mutagenesis, optical trapping, and Langevin dynamics simulation, we resolved the structure of PP7, T4P, and the PP7/T4P complex and showed that T4P detachment is driven by the affinity between the phage maturation protein and its bound pilin, plus the pilus retraction force and speed, and pilus bending. Pilus detachment may be widespread among other ssRNA phages and their retractile pilus systems and offers new prospects for antibacterial prophylaxis and therapeutics.
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Affiliation(s)
- Jirapat Thongchol
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Zihao Yu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Laith Harb
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Yiruo Lin
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Matthias Koch
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Matthew Theodore
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Utkarsh Narsaria
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Joshua Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yinghao Wu
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, NY 10461, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
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11
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Sánchez-Peña A, Winans JB, Nadell CD, Limoli DH. Pseudomonas aeruginosa surface motility and invasion into competing communities enhances interspecies antagonism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.588010. [PMID: 38617332 PMCID: PMC11014535 DOI: 10.1101/2024.04.03.588010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are prevalent, difficult to eradicate, and associated with poor health outcomes. Therefore, understanding interactions between these pathogens is important to inform improved treatment development. We previously demonstrated that P. aeruginosa is attracted to S. aureus using type IV pili-mediated chemotaxis, but the impact of attraction on S. aureus growth and physiology remained unknown. Using live single-cell confocal imaging to visualize microcolony structure, spatial organization, and survival of S. aureus during coculture, we found that interspecies chemotaxis provides P. aeruginosa a competitive advantage by promoting invasion into and disruption of S. aureus microcolonies. This behavior renders S. aureus susceptible to P. aeruginosa antimicrobials. Conversely, in the absence of type IV pilus motility, P. aeruginosa cells exhibit reduced invasion of S. aureus colonies. Instead, P. aeruginosa builds a cellular barrier adjacent to S. aureus and secretes diffusible, bacteriostatic antimicrobials like 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) into the S. aureus colonies. P. aeruginosa reduced invasion leads to the formation of denser and thicker S. aureus colonies with significantly increased HQNO-mediated lactic acid fermentation, a physiological change that could complicate the effective treatment of infections. Finally, we show that P. aeruginosa motility modifications of spatial structure enhance competition against S. aureus. Overall, these studies build on our understanding of how P. aeruginosa type IV pili-mediated interspecies chemotaxis mediates polymicrobial interactions, highlighting the importance of spatial positioning in mixed-species communities.
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Affiliation(s)
- Andrea Sánchez-Peña
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - James B Winans
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Carey D Nadell
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Dominique H Limoli
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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12
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Verma RK, Gondu P, Saha T, Chatterjee S. The Global Transcription Regulator XooClp Governs Type IV Pili System-Mediated Bacterial Virulence by Directly Binding to TFP-Chp Promoters to Coordinate Virulence Associated Functions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:357-369. [PMID: 38105438 DOI: 10.1094/mpmi-07-23-0100-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Type IV pili (TFP) play a crucial role in the sensing of the external environment for several bacteria. This surface sensing is essential for the lifestyle transitions of several bacteria and involvement in pathogenesis. However, the precise mechanisms underlying TFP's integration of environmental cues, particularly in regulating the TFP-Chp system and its effects on Xanthomonas physiology, social behavior, and virulence, remain poorly understood. In this study, we focused on investigating Clp, a global transcriptional regulator similar to CRP-like proteins, in Xanthomonas oryzae pv. oryzae, a plant pathogen. Our findings reveal that Clp integrates environmental cues detected through diffusible signaling factor (DSF) quorum sensing into the TFP-Chp regulatory system. It accomplishes this by directly binding to TFP-Chp promoters in conjunction with intracellular levels of cyclic-di-GMP, a ubiquitous bacterial second messenger, thereby controlling TFP expression. Moreover, Clp-mediated regulation is involved in regulating several cellular processes, including the production of virulence-associated functions. Collectively, these processes contribute to host colonization and disease initiation. Our study elucidates the intricate regulatory network encompassing Clp, environmental cues, and the TFP-Chp system, providing insights into the molecular mechanisms that drive bacterial virulence in Xanthomonas spp. These findings offer valuable knowledge regarding Xanthomonas pathogenicity and present new avenues for innovative strategies aimed at combating plant diseases caused by these bacteria. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Raj Kumar Verma
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Parimala Gondu
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Tirthankar Saha
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
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13
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Shahzad S, Krug SA, Mouriño S, Huang W, Kane MA, Wilks A. Pseudomonas aeruginosa heme metabolites biliverdin IXβ and IXδ are integral to lifestyle adaptations associated with chronic infection. mBio 2024; 15:e0276323. [PMID: 38319089 PMCID: PMC10936436 DOI: 10.1128/mbio.02763-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/11/2023] [Indexed: 02/07/2024] Open
Abstract
Pseudomonas aeruginosa is a versatile opportunistic pathogen requiring iron for its survival and virulence within the host. The ability to switch to heme as an iron source and away from siderophore uptake provides an advantage in chronic infection. We have recently shown the extracellular heme metabolites biliverdin IXβ (BVIXβ) and BVIXδ positively regulate the heme-dependent cell surface signaling cascade. We further investigated the role of BVIXβ and BVIXδ in cell signaling utilizing allelic strains lacking a functional heme oxygenase (hemOin) or one reengineered to produce BVIXα (hemOα). Compared to PAO1, both strains show a heme-dependent growth defect, decreased swarming and twitching, and less robust biofilm formation. Interestingly, the motility and biofilm defects were partially rescued on addition of exogenous BVIXβ and BVIXδ. Utilizing liquid chromatography-tandem mass spectrometry, we performed a comparative proteomics and metabolomics analysis of PAO1 versus the allelic strains in shaking and static conditions. In shaking conditions, the hemO allelic strains showed a significant increase in proteins involved in quorum sensing, phenazine production, and chemotaxis. Metabolite profiling further revealed increased levels of Pseudomonas quinolone signal and phenazine metabolites. In static conditions, we observed a significant repression of chemosensory pathways and type IV pili biogenesis proteins as well as several phosphodiesterases associated with biofilm dispersal. We propose BVIX metabolites function as signaling and chemotactic molecules integrating heme utilization as an iron source into the adaptation of P. aeruginosa from a planktonic to sessile lifestyle. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa causes long-term chronic infection in the airways of cystic fibrosis patients. The ability to scavenge iron and to establish chronic infection within this environment coincides with a switch to utilize heme as the primary iron source. Herein, we show the heme metabolites biliverdin beta and delta are themselves important signaling molecules integrating the switch in iron acquisition systems with cooperative behaviors such as motility and biofilm formation that are essential for long-term chronic infection. These significant findings will enhance the development of viable multi-targeted therapeutics effective against both heme utilization and cooperative behaviors essential for survival and persistence within the host.
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Affiliation(s)
- Saba Shahzad
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Samuel A. Krug
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Susana Mouriño
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
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14
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Zhang J, Ma Q, Wang C, Meng N. Unraveling the signaling roles of indole in an opportunistic pathogen Pseudomonas aeruginosa strain Jade-X. CHEMOSPHERE 2024; 352:141482. [PMID: 38387666 DOI: 10.1016/j.chemosphere.2024.141482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/29/2023] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
Pseudomonas aeruginosa, which can produce several toxins and form biofilm, is listed among the priority pathogens. Indole is a ubiquitous aromatic pollutant and signaling molecule produced by tryptophanase in bacteria. Herein, the impacts of indole on a newly isolated P. aeruginosa strain Jade-X were systematically investigated. Indole (0.5-2.0 mM) enhanced the biofilm production by 1.33-2.31-fold after 24 h incubation at 30 °C. However, the effects indole on biofilm formation were intricate and closely intertwined with factors such as incubation temperature, bacterial growth stage, and indole concentration. The twitching motility was enhanced by 1.15-1.99-fold by indole, potentially facilitating surface exploration and biofilm development. Indole reduced the production of virulence factors (pyocyanin and pyoverdine) as well as altered the surface properties (zeta potential and hydrophobicity). Transcriptional analysis revealed that indole (1.0 mM) significantly downregulated mexGHI-opmD efflux genes (4.73-6.91-fold) and virulence-related genes (pqs, pch, and pvd clusters, and flagella-related genes), while upregulating pili-related genes in strain Jade-X. The quorum sensing related signal regulators, including RhlR, LasR, and MvfR (PqsR), were not altered by indole, while other six transcriptional regulators (AmrZ, BfmR, PchR, QscR, SoxR, and SphR) were significantly affected, implying that indole effects might be regulated in a complex and delicate manner. This study should provide new insights into our understanding of indole signaling roles.
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Affiliation(s)
- Jiaxin Zhang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Qiao Ma
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Caihong Wang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Nan Meng
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
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15
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Patino R, Kühn MJ, Macmillan H, Inclan YF, Chavez I, Von Dollen J, Johnson JR, Swaney DL, Krogan NJ, Persat A, Engel JN. Spatial control of sensory adaptation modulates mechanosensing in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.27.582188. [PMID: 38464290 PMCID: PMC10925122 DOI: 10.1101/2024.02.27.582188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Sensory signaling pathways use adaptation to dynamically respond to changes in their environment. Here, we report the mechanism of sensory adaptation in the Pil-Chp mechanosensory system, which the important human pathogen Pseudomonas aeruginosa uses to sense mechanical stimuli during surface exploration. Using biochemistry, genetics, and cell biology, we discovered that the enzymes responsible for adaptation, a methyltransferase and a methylesterase, are segregated to opposing cell poles as P. aeruginosa explore surfaces. By coordinating the localization of both enzymes, we found that the Pil-Chp response regulators influence local receptor methylation, the molecular basis of bacterial sensory adaptation. We propose a model in which adaptation during mechanosensing spatially resets local receptor methylation, and thus Pil-Chp signaling, to modulate the pathway outputs, which are involved in P. aeruginosa virulence. Despite decades of bacterial sensory adaptation studies, our work has uncovered an unrecognized mechanism that bacteria use to achieve adaptation to sensory stimuli.
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16
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Yalkut K, Ben Ali Hassine S, Basaran E, Kula C, Ozcan A, Avci FG, Keskin O, Sariyar Akbulut B, Ozbek P. Attenuation of Type IV pili activity by natural products. J Biomol Struct Dyn 2024:1-11. [PMID: 38305801 DOI: 10.1080/07391102.2024.2310781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/20/2024] [Indexed: 02/03/2024]
Abstract
The virulence factor Type IV pili (T4P) are surface appendages used by the opportunistic pathogen Pseudomonas aeruginosa for twitching motility and adhesion in the environment and during infection. Additionally, the use of these appendages by P. aeruginosa for biofilm formation increases its virulence and drug resistance. Therefore, attenuation of the activity of T4P would be desirable to control P. aeruginosa infections. Here, a computational approach has been pursued to screen natural products that can be used for this purpose. PilB, the elongation ATPase of the T4P machinery in P. aeruginosa, has been selected as the target subunit and virtual screening of FDA-approved drugs has been conducted. Screening identified two natural compounds, ergoloid and irinotecan, as potential candidates for inhibiting this T4P-associated ATPase in P. aeruginosa. These candidate compounds underwent further rigorous evaluation through molecular dynamics (MD) simulations and then through in vitro twitching motility and biofilm inhibition assays. Notably, ergoloid emerged as a particularly promising candidate for weakening the T4P activity by inhibiting the elongation ATPases associated with T4P. This repurposing study paves the way for the timely discovery of antivirulence drugs as an alternative to classical antibiotic treatments to help combat infections caused by P. aeruginosa and related pathogens.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kerem Yalkut
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
| | - Soumaya Ben Ali Hassine
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
- Department of Bioengineering, Faculty of Engineering and Natural Sciences, Uskudar University, Istanbul, Turkey
| | - Esra Basaran
- Graduate School of Sciences and Engineering, Koc University, Istanbul, Turkey
| | - Ceyda Kula
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
| | - Aslıhan Ozcan
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
| | - Fatma Gizem Avci
- Department of Bioengineering, Faculty of Engineering and Natural Sciences, Uskudar University, Istanbul, Turkey
| | - Ozlem Keskin
- Graduate School of Sciences and Engineering, Koc University, Istanbul, Turkey
| | - Berna Sariyar Akbulut
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
| | - Pemra Ozbek
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, Turkey
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17
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Yarrington KD, Shendruk TN, Limoli DH. The type IV pilus chemoreceptor PilJ controls chemotaxis of one bacterial species towards another. PLoS Biol 2024; 22:e3002488. [PMID: 38349934 PMCID: PMC10896506 DOI: 10.1371/journal.pbio.3002488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/26/2024] [Accepted: 01/05/2024] [Indexed: 02/15/2024] Open
Abstract
Bacteria live in social communities, where the ability to sense and respond to interspecies and environmental signals is critical for survival. We previously showed the pathogen Pseudomonas aeruginosa detects secreted peptides from bacterial competitors and navigates through interspecies signal gradients using pilus-based motility. Yet, it was unknown whether P. aeruginosa utilizes a designated chemosensory system for this behavior. Here, we performed a systematic genetic analysis of a putative pilus chemosensory system, followed by high-speed live-imaging and single-cell tracking, to reveal behaviors of mutants that retain motility but are blind to interspecies signals. The enzymes predicted to methylate (PilK) and demethylate (ChpB) the putative pilus chemoreceptor, PilJ, are necessary for cells to control the direction of migration. While these findings implicate PilJ as a bona fide chemoreceptor, such function had yet to be experimentally defined, as full-length PilJ is essential for motility. Thus, we constructed systematic genetic modifications of PilJ and found that without the predicted ligand binding domains or predicted methylation sites, cells lose the ability to detect competitor gradients, despite retaining pilus-mediated motility. Chemotaxis trajectory analysis revealed that increased probability and size of P. aeruginosa pilus-mediated steps towards S. aureus peptides, versus steps away, determines motility bias in wild type cells. However, PilJ mutants blind to interspecies signals take less frequent steps towards S. aureus or steps of equal size towards and away. Collectively, this work uncovers the chemosensory nature of PilJ, provides insight into how cell movements are biased during pilus-based chemotaxis, and identifies chemotactic interactions necessary for bacterial survival in polymicrobial communities, revealing putative pathways where therapeutic intervention might disrupt bacterial communication.
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Affiliation(s)
- Kaitlin D. Yarrington
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Tyler N. Shendruk
- School of Physics and Astronomy, The University of Edinburgh, Edinburgh, United Kingdom
| | - Dominique H. Limoli
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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18
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Dayton H, Kiss J, Wei M, Chauhan S, LaMarre E, Cornell WC, Morgan CJ, Janakiraman A, Min W, Tomer R, Price-Whelan A, Nirody JA, Dietrich LEP. Cellular arrangement impacts metabolic activity and antibiotic tolerance in Pseudomonas aeruginosa biofilms. PLoS Biol 2024; 22:e3002205. [PMID: 38300958 PMCID: PMC10833521 DOI: 10.1371/journal.pbio.3002205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 12/19/2023] [Indexed: 02/03/2024] Open
Abstract
Cells must access resources to survive, and the anatomy of multicellular structures influences this access. In diverse multicellular eukaryotes, resources are provided by internal conduits that allow substances to travel more readily through tissue than they would via diffusion. Microbes growing in multicellular structures, called biofilms, are also affected by differential access to resources and we hypothesized that this is influenced by the physical arrangement of the cells. In this study, we examined the microanatomy of biofilms formed by the pathogenic bacterium Pseudomonas aeruginosa and discovered that clonal cells form striations that are packed lengthwise across most of a mature biofilm's depth. We identified mutants, including those defective in pilus function and in O-antigen attachment, that show alterations to this lengthwise packing phenotype. Consistent with the notion that cellular arrangement affects access to resources within the biofilm, we found that while the wild type shows even distribution of tested substrates across depth, the mutants show accumulation of substrates at the biofilm boundaries. Furthermore, we found that altered cellular arrangement within biofilms affects the localization of metabolic activity, the survival of resident cells, and the susceptibility of subpopulations to antibiotic treatment. Our observations provide insight into cellular features that determine biofilm microanatomy, with consequences for physiological differentiation and drug sensitivity.
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Affiliation(s)
- Hannah Dayton
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Julie Kiss
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, New York, United States of America
| | - Shradha Chauhan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Emily LaMarre
- Program in Biology, The Graduate Center, City University of New York, New York, New York, United States of America
| | - William Cole Cornell
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Chase J. Morgan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Anuradha Janakiraman
- Program in Biology, The Graduate Center, City University of New York, New York, New York, United States of America
| | - Wei Min
- Department of Chemistry, Columbia University, New York, New York, United States of America
| | - Raju Tomer
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Jasmine A. Nirody
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, United States of America
| | - Lars E. P. Dietrich
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
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19
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Chen Y, Topo EJ, Nan B, Chen J. Mathematical modeling of mechanosensitive reversal control in Myxococcus xanthus. Front Microbiol 2024; 14:1294631. [PMID: 38260904 PMCID: PMC10803039 DOI: 10.3389/fmicb.2023.1294631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Adjusting motility patterns according to environmental cues is important for bacterial survival. Myxococcus xanthus, a bacterium moving on surfaces by gliding and twitching mechanisms, modulates the reversal frequency of its front-back polarity in response to mechanical cues like substrate stiffness and cell-cell contact. In this study, we propose that M. xanthus's gliding machinery senses environmental mechanical cues during force generation and modulates cell reversal accordingly. To examine our hypothesis, we expand an existing mathematical model for periodic polarity reversal in M. xanthus, incorporating the experimental data on the intracellular dynamics of the gliding machinery and the interaction between the gliding machinery and a key polarity regulator. The model successfully reproduces the dependence of cell reversal frequency on substrate stiffness observed in M. xanthus gliding. We further propose reversal control networks between the gliding and twitching motility machineries to explain the opposite reversal responses observed in wild type M. xanthus cells that possess both motility mechanisms. These results provide testable predictions for future experimental investigations. In conclusion, our model suggests that the gliding machinery in M. xanthus can function as a mechanosensor, which transduces mechanical cues into a cell reversal signal.
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Affiliation(s)
- Yirui Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Genetics, Bioinformatics and Computational Biology Graduate Program, Virginia Tech, Blacksburg, VA, United States
| | - Elias J. Topo
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, United States
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, United States
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20
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Maffei E, Woischnig AK, Burkolter MR, Heyer Y, Humolli D, Thürkauf N, Bock T, Schmidt A, Manfredi P, Egli A, Khanna N, Jenal U, Harms A. Phage Paride can kill dormant, antibiotic-tolerant cells of Pseudomonas aeruginosa by direct lytic replication. Nat Commun 2024; 15:175. [PMID: 38168031 PMCID: PMC10761892 DOI: 10.1038/s41467-023-44157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024] Open
Abstract
Bacteriophages are ubiquitous viral predators that have primarily been studied using fast-growing laboratory cultures of their bacterial hosts. However, microbial life in nature is mostly in a slow- or non-growing, dormant state. Here, we show that diverse phages can infect deep-dormant bacteria and suspend their replication until the host resuscitates ("hibernation"). However, a newly isolated Pseudomonas aeruginosa phage, named Paride, can directly replicate and induce the lysis of deep-dormant hosts. While non-growing bacteria are notoriously tolerant to antibiotic drugs, the combination with Paride enables the carbapenem meropenem to eradicate deep-dormant cultures in vitro and to reduce a resilient bacterial infection of a tissue cage implant in mice. Our work might inspire new treatments for persistent bacterial infections and, more broadly, highlights two viral strategies to infect dormant bacteria (hibernation and direct replication) that will guide future studies on phage-host interactions.
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Affiliation(s)
- Enea Maffei
- Biozentrum, University of Basel, Basel, Switzerland
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland
| | - Anne-Kathrin Woischnig
- Laboratory of Infection Biology, Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland
| | - Marco R Burkolter
- Biozentrum, University of Basel, Basel, Switzerland
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland
| | - Yannik Heyer
- Biozentrum, University of Basel, Basel, Switzerland
| | - Dorentina Humolli
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland
| | | | - Thomas Bock
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Adrian Egli
- Division of Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, University and University Hospital of Basel, Basel, Switzerland
| | - Nina Khanna
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland
- Laboratory of Infection Biology, Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland
| | - Urs Jenal
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexander Harms
- Biozentrum, University of Basel, Basel, Switzerland.
- Institute of Food, Nutrition and Health, D-HEST, ETH Zurich, Zurich, Switzerland.
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21
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Bhuyan S, Dutta L, Begum S, Giri SJ, Jain M, Mandal M, Ray SK. A study on twitching motility dynamics in Ralstonia solanacearum microcolonies by live imaging. J Basic Microbiol 2024; 64:42-49. [PMID: 37612794 DOI: 10.1002/jobm.202300272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/15/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
Ralstonia solanacearum is a rod-shaped phytopathogenic bacterium that causes lethal wilt disease in many plants. On solid agar growth medium, in the early hour of the growth of the bacterial colony, the type IV pili-mediated twitching motility, which is important for its virulence and biofilm formation, is prominently observed under the microscope. In this study, we have done a detailed observation of twitching motility in R. solanacearum colony. In the beginning, twitching motility in the microcolonies was observed as a density-dependent phenomenon that influences the shape of the microcolonies. No such phenomenon was observed in Escherichia coli, where twitching motility is absent. In the early phase of colony growth, twitching motility exhibited by the cells at the peripheral region of the colony was more prominent than the cells toward the center of the colony. Using time-lapse photography and merging the obtained photomicrographs into a video, twitching motility was observed as an intermittent phenomenon that progresses in layers in all directions as finger-like projections at the peripheral region of a bacterial colony. Each layer of bacteria twitches on top of the other and produces a multilayered film-like appearance. We found that the duration between the emergence of each layer diminishes progressively as the colony becomes older. This study on twitching motility demonstrates distinctly heterogeneity among the cells within a colony regarding their dynamics and the influence of microcolonies on each other regarding their morphology.
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Affiliation(s)
- Shuvam Bhuyan
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Lukapriya Dutta
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Shuhada Begum
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Shubhra J Giri
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Monika Jain
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Manabendra Mandal
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
| | - Suvendra K Ray
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, Assam, India
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22
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Ungor I, Apidianakis Y. Bacterial synergies and antagonisms affecting Pseudomonas aeruginosa virulence in the human lung, skin and intestine. Future Microbiol 2024; 19:141-155. [PMID: 37843410 DOI: 10.2217/fmb-2022-0155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023] Open
Abstract
Pseudomonas aeruginosa requires a significant breach in the host defense to cause an infection. While its virulence factors are well studied, its tropism cannot be explained only by studying its interaction with the host. Why are P. aeruginosa infections so rare in the intestine compared with the lung and skin? There is not enough evidence to claim specificity in virulence factors deployed by P. aeruginosa in each anatomical site, and host physiology differences between the lung and the intestine cannot easily explain the observed differences in virulence. This perspective highlights a relatively overlooked parameter in P. aeruginosa virulence, namely, potential synergies with bacteria found in the human skin and lung, as well as antagonisms with bacteria of the human intestine.
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Affiliation(s)
- Izel Ungor
- Department of Biological Sciences, University of Cyprus, Nicosia, 2109, Cyprus
| | - Yiorgos Apidianakis
- Department of Biological Sciences, University of Cyprus, Nicosia, 2109, Cyprus
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23
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Bondoc-Naumovitz KG, Laeverenz-Schlogelhofer H, Poon RN, Boggon AK, Bentley SA, Cortese D, Wan KY. Methods and Measures for Investigating Microscale Motility. Integr Comp Biol 2023; 63:1485-1508. [PMID: 37336589 PMCID: PMC10755196 DOI: 10.1093/icb/icad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023] Open
Abstract
Motility is an essential factor for an organism's survival and diversification. With the advent of novel single-cell technologies, analytical frameworks, and theoretical methods, we can begin to probe the complex lives of microscopic motile organisms and answer the intertwining biological and physical questions of how these diverse lifeforms navigate their surroundings. Herein, we summarize the main mechanisms of microscale motility and give an overview of different experimental, analytical, and mathematical methods used to study them across different scales encompassing the molecular-, individual-, to population-level. We identify transferable techniques, pressing challenges, and future directions in the field. This review can serve as a starting point for researchers who are interested in exploring and quantifying the movements of organisms in the microscale world.
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Affiliation(s)
| | | | - Rebecca N Poon
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Alexander K Boggon
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Samuel A Bentley
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Dario Cortese
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Kirsty Y Wan
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
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24
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Forti F, Bertoli C, Cafora M, Gilardi S, Pistocchi A, Briani F. Identification and impact on Pseudomonas aeruginosa virulence of mutations conferring resistance to a phage cocktail for phage therapy. Microbiol Spectr 2023; 11:e0147723. [PMID: 37966242 PMCID: PMC10714927 DOI: 10.1128/spectrum.01477-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE In this work, we identified the putative receptors of 16 Pseudomonas phages and evaluated how resistance to phages recognizing different bacterial receptors may affect the virulence. Our findings are relevant for the implementation of phage therapy of Pseudomonas aeruginosa infections, which are difficult to treat with antibiotics. Overall, our results highlight the need to modify natural phages to enlarge the repertoire of receptors exploited by therapeutic phages and suggest that phages using the PAO1-type T4P as receptor may have limited value for the therapy of the cystic fibrosis infection.
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Affiliation(s)
- Francesca Forti
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Claudia Bertoli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Marco Cafora
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | - Sara Gilardi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Anna Pistocchi
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
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25
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Di Pilato V, Willison E, Marchese A. The microbiology and pathogenesis of nonfermenting Gram-negative infections. Curr Opin Infect Dis 2023; 36:537-544. [PMID: 37732777 PMCID: PMC10624403 DOI: 10.1097/qco.0000000000000969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
PURPOSE OF REVIEW This review provides an overview of most recent evidence about pathogenesis traits and virulence factors contributing to successful colonization or infection by P. aeruginosa , A. baumannii , S. maltophilia and B. cepacia complex, among the most clinically relevant nonfermenting Gram-negative bacteria (NFGNB). RECENT FINDINGS The growing clinical importance of NFGNB as important opportunistic pathogens causing difficult-to-treat infections in a fragile patients' population in stressed by numerous studies. Identification of novel virulence factors and deciphering of their mechanisms of action have greatly furthered our understanding of NFGNB pathogenesis, revealing that each pathogen-specific armamentarium of virulence factors (adhesins, motility, capsule, biofilm, lipopolysaccharide, exotoxins, exoenzymes, secretion systems, siderophores) can be likely responsible for the difference in the pathophysiology even in the context of a similar infection site. Emerging evidence of the immunomodulatory effect of some virulence factors is also acknowledged. SUMMARY NFGNB continue to be a serious global problem as cause of life-threatening opportunistic infections, owing to a highly heterogeneous content of virulence factors and their extensive number of intrinsic resistance mechanisms. Further efforts in development of novel effective antimicrobials and of alternative strategies targeting key virulence factors are warranted.
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Affiliation(s)
- Vincenzo Di Pilato
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa
| | - Edward Willison
- Microbiology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Anna Marchese
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa
- Microbiology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
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26
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Jazi MA, Chirani AS, Hajikhani B, Ebrahimipour G, Goudarzi M. Unraveling the immunopotentiation of P. aeruginosa PAPI-1 encoded pilin: From immunoinformatics survey to active immunization. Int Immunopharmacol 2023; 125:111197. [PMID: 37951200 DOI: 10.1016/j.intimp.2023.111197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/03/2023] [Accepted: 11/05/2023] [Indexed: 11/13/2023]
Abstract
For protection against Pseudomonas aeruginosa strains, a number of vaccine candidates have been introduced thus far. However, despite significant attempts in recent years, there are currently no effective immunogenic Bacteria components against this pathogen on the market. P. aeruginosa encoding a number of different virulence characteristics, as well as the rapid growth in multiple drug-resistant forms, has raised numerous health issues throughout the world. This pathogen expresses three different subtypes of T4P, including IVa, IVb, and Tad which are involved in various cellular processes. Highly virulent strains of P. aeruginosa can encode well-conserved PAPI-1 associated PilS2 pilus. Designing an efficient pili-based immunotherapy approach targeting P. aeruginosa pilus has remained controversial due to the variability heterogeneousness and hidden well-preserved binding site of T4aP and no approved human study is commercially based on IVa pilin. In this investigation, for the first time, through analytical immunoinformatics, we designed an effective chimeric PilS2 immunogen against numerous clinically important P. aeruginosa strains. Through active immunization against the extremely conserved region of the chimeric PilS2 pilin, we showed that PilS2 chimeric pilin whether administered alone or formulated with alum as an adjuvant could substantially stimulate humoral immunological responses in BALB/c mice. Based on these findings, we conclude that PilS2 pilin is therapeutically effective against a variety of highly virulent strains of P. aeruginosa and can act as a new immunogen for more research towards the creation of efficient immunotherapy techniques against the P. aeruginosa as a dexterous pathogen.
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Affiliation(s)
- Mojgan Arefian Jazi
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | | | - Bahareh Hajikhani
- Department of Microbiology, School of Medicine Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gholamhossein Ebrahimipour
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | - Mehdi Goudarzi
- Department of Microbiology, School of Medicine Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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27
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Migration of surface-associated microbial communities in spaceflight habitats. Biofilm 2023; 5:100109. [PMID: 36909662 PMCID: PMC9999172 DOI: 10.1016/j.bioflm.2023.100109] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/05/2023] [Accepted: 02/17/2023] [Indexed: 02/26/2023] Open
Abstract
Astronauts are spending longer periods locked up in ships or stations for scientific and exploration spatial missions. The International Space Station (ISS) has been inhabited continuously for more than 20 years and the duration of space stays by crews could lengthen with the objectives of human presence on the moon and Mars. If the environment of these space habitats is designed for the comfort of astronauts, it is also conducive to other forms of life such as embarked microorganisms. The latter, most often associated with surfaces in the form of biofilm, have been implicated in significant degradation of the functionality of pieces of equipment in space habitats. The most recent research suggests that microgravity could increase the persistence, resistance and virulence of pathogenic microorganisms detected in these communities, endangering the health of astronauts and potentially jeopardizing long-duration manned missions. In this review, we describe the mechanisms and dynamics of installation and propagation of these microbial communities associated with surfaces (spatial migration), as well as long-term processes of adaptation and evolution in these extreme environments (phenotypic and genetic migration), with special reference to human health. We also discuss the means of control envisaged to allow a lasting cohabitation between these vibrant microscopic passengers and the astronauts.
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28
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Chichón G, López M, de Toro M, Ruiz-Roldán L, Rojo-Bezares B, Sáenz Y. Spread of Pseudomonas aeruginosa ST274 Clone in Different Niches: Resistome, Virulome, and Phylogenetic Relationship. Antibiotics (Basel) 2023; 12:1561. [PMID: 37998763 PMCID: PMC10668709 DOI: 10.3390/antibiotics12111561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 11/25/2023] Open
Abstract
Pseudomonas aeruginosa ST274 is an international epidemic high-risk clone, mostly associated with hospital settings and appears to colonize cystic fibrosis (CF) patients worldwide. To understand the relevant mechanisms for its success, the biological and genomic characteristics of 11 ST274-P. aeruginosa strains from clinical and non-clinical origins were analyzed. The extensively drug-resistant (XDR/DTR), the non-susceptible to at least one agent (modR), and the lasR-truncated (by ISPsp7) strains showed a chronic infection phenotype characterized by loss of serotype-specific antigenicity and low motility. Furthermore, the XDR/DTR and modR strains presented low pigment production and biofilm formation, which were very high in the lasR-truncated strain. Their whole genome sequences were compared with other 14 ST274-P. aeruginosa genomes available in the NCBI database, and certain associations have been primarily detected: blaOXA-486 and blaPDC-24 genes, serotype O:3, exoS+/exoU- genotype, group V of type IV pili, and pyoverdine locus class II. Other general molecular markers highlight the absence of vqsM and pldA/tleS genes and the presence of the same mutational pattern in genes involving two-component sensor-regulator systems PmrAB and CreBD, exotoxin A, quorum-sensing RhlI, beta-lactamase expression regulator AmpD, PBP1A, or FusA2 elongation factor G. The proportionated ST274-P. aeruginosa results could serve as the basis for more specific studies focused on better antibiotic stewardship and new therapeutic developments.
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Affiliation(s)
- Gabriela Chichón
- Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
| | - María López
- Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
| | - María de Toro
- Plataforma de Genómica y Bioinformática, Centro de Investigación Biomédica de La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
| | - Lidia Ruiz-Roldán
- Joint Research Unit “Infection and Public Health” FISABIO-University of Valencia, Institute for Integrative Systems Biology I2SysBio (CSIC-UV), Av. de Catalunya 21, 46020 Valencia, Spain
| | - Beatriz Rojo-Bezares
- Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
| | - Yolanda Sáenz
- Área de Microbiología Molecular, Centro de Investigación Biomédica de La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
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29
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Wang N, Lei T, Zhu Y, Li Y, Cai H, Zhang P, Leptihn S, Zhou J, Ke H, Gao B, Feng Y, Hua X, Qu T. Characterization of two novel VIM-type metallo-β-lactamases, VIM-84 and VIM-85, associated with the spread of IncP-2 megaplasmids in Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0154423. [PMID: 37707305 PMCID: PMC10580930 DOI: 10.1128/spectrum.01544-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/17/2023] [Indexed: 09/15/2023] Open
Abstract
This study aimed to characterize two novel VIM-type metallo-β-lactamases, VIM-84 and VIM-85, and reveal the important role of the IncP-2 type megaplasmids in the spread of antimicrobial resistance (AMR) genes. VIM-84 and VIM-85 were encoded by two novel genes bla VIM-84 and bla VIM-85 which showed similarity to bla VIM-24. Both bla VIM-84 and bla VIM-85 are harbored into class 1 integrons embedded into the Tn1403 transposon. The bla VIM-85 gene was identified in a megaplasmid, which was related to 17 megaplasmid sequences with sizes larger than 430 kb, deposited previously in Genbank. A comparative analysis of complete plasmid sequences showed highly similar backbone regions and various AMR genes. A phylogenetic tree revealed that these megaplasmids, which were widely distributed globally, were vehicles for the spread of AMR genes. The bla VIM-24, bla VIM-84, and bla VIM-85 genes were cloned into pGK1900, and the recombinant vectors were further transformed into Escherichia coli DH5α and Pseudomonas aeruginosa PAO1. The antimicrobial susceptibility test of the cloning strains showed high levels of resistance to β-lactams while they remained susceptible to aztreonam. Enzymatic tests revealed that both, VIM-84 and VIM-85, exhibited higher activity in hydrolyzing β-lactams compared to VIM-24. A D117N mutation found in VIM-24 affected binding to the antibiotics. IMPORTANCE The metallo-β-lactamases-producing Pseudomonas aeruginosa strains play an important role in hospital outbreaks and the VIM-type enzyme is the most prevalent in European countries. Two novel VIM-type enzymes in our study, VIM-84 and VIM-85, have higher levels of resistance to β-lactams and greater hydrolytic activities for most β-lactams compared with VIM-24. Both bla VIM-84 and bla VIM-85 are harbored into class 1 integrons embedded into the Tn1403 transposon. Notably, the genes bla VIM-85 are carried by three different IncP-2-type megaplasmids which are distributed locally and appear responsible for the spread of antimicrobial resistance genes in hospital settings.
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Affiliation(s)
- Nanfei Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Tailong Lei
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yiwei Zhu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yue Li
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Heng Cai
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Piaopiao Zhang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Sebastian Leptihn
- Department of Biochemistry, Health and Medical University, Erfurt, Germany
- Department of Antimicrobial Biotechnology, Fraunhofer Institute for Cell Therapy & Immunology, Leipzig, Germany
| | - Junxin Zhou
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Huanhuan Ke
- Department of Biophysics, and Department of Infectious Disease of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bo Gao
- Department of Biophysics, and Department of Infectious Disease of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Feng
- Department of Biophysics, and Department of Infectious Disease of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Alibaba-Zhejiang University Joint Research Center of Future Digital Healthcare, Hangzhou, Zhejiang, China
| | - Tingting Qu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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30
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Ghosh M, Raghav S, Ghosh P, Maity S, Mohela K, Jain D. Structural analysis of novel drug targets for mitigation of Pseudomonas aeruginosa biofilms. FEMS Microbiol Rev 2023; 47:fuad054. [PMID: 37771093 DOI: 10.1093/femsre/fuad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 09/30/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen responsible for acute and chronic, hard to treat infections. Persistence of P. aeruginosa is due to its ability to develop into biofilms, which are sessile bacterial communities adhered to substratum and encapsulated in layers of self-produced exopolysaccharides. These biofilms provide enhanced protection from the host immune system and resilience towards antibiotics, which poses a challenge for treatment. Various strategies have been expended for combating biofilms, which involve inhibiting biofilm formation or promoting their dispersal. The current remediation approaches offer some hope for clinical usage, however, treatment and eradication of preformed biofilms is still a challenge. Thus, identifying novel targets and understanding the detailed mechanism of biofilm regulation becomes imperative. Structure-based drug discovery (SBDD) provides a powerful tool that exploits the knowledge of atomic resolution details of the targets to search for high affinity ligands. This review describes the available structural information on the putative target protein structures that can be utilized for high throughput in silico drug discovery against P. aeruginosa biofilms. Integrating available structural information on the target proteins in readily accessible format will accelerate the process of drug discovery.
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Affiliation(s)
- Moumita Ghosh
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Shikha Raghav
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Puja Ghosh
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Swagatam Maity
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Kavery Mohela
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurugram Expressway, Faridabad, Haryana-121001, India
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31
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Dayton H, Kiss J, Wei M, Chauhan S, LaMarre E, Cornell WC, Morgan CJ, Janakiraman A, Min W, Tomer R, Price-Whelan A, Nirody JA, Dietrich LE. Cell arrangement impacts metabolic activity and antibiotic tolerance in Pseudomonas aeruginosa biofilms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.20.545666. [PMID: 37645902 PMCID: PMC10462148 DOI: 10.1101/2023.06.20.545666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Cells must access resources to survive, and the anatomy of multicellular structures influences this access. In diverse multicellular eukaryotes, resources are provided by internal conduits that allow substances to travel more readily through tissue than they would via diffusion. Microbes growing in multicellular structures, called biofilms, are also affected by differential access to resources and we hypothesized that this is influenced by the physical arrangement of the cells. In this study, we examined the microanatomy of biofilms formed by the pathogenic bacterium Pseudomonas aeruginosa and discovered that clonal cells form striations that are packed lengthwise across most of a mature biofilm's depth. We identified mutants, including those defective in pilus function and in O-antigen attachment, that show alterations to this lengthwise packing phenotype. Consistent with the notion that cellular arrangement affects access to resources within the biofilm, we found that while the wild type shows even distribution of tested substrates across depth, the mutants show accumulation of substrates at the biofilm boundaries. Furthermore, we found that altered cellular arrangement within biofilms affects the localization of metabolic activity, the survival of resident cells, and the susceptibility of subpopulations to antibiotic treatment. Our observations provide insight into cellular features that determine biofilm microanatomy, with consequences for physiological differentiation and drug sensitivity.
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Affiliation(s)
- Hannah Dayton
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Julie Kiss
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Shradha Chauhan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Emily LaMarre
- Program in Biology, The Graduate Center, City University of New York, New York, NY 10016
| | | | - Chase J. Morgan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Anuradha Janakiraman
- Program in Biology, The Graduate Center, City University of New York, New York, NY 10016
| | - Wei Min
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Raju Tomer
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Jasmine A Nirody
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10025
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32
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Rossy T, Distler T, Meirelles LA, Pezoldt J, Kim J, Talà L, Bouklas N, Deplancke B, Persat A. Pseudomonas aeruginosa type IV pili actively induce mucus contraction to form biofilms in tissue-engineered human airways. PLoS Biol 2023; 21:e3002209. [PMID: 37527210 PMCID: PMC10393179 DOI: 10.1371/journal.pbio.3002209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 06/21/2023] [Indexed: 08/03/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa causes antibiotic-recalcitrant pneumonia by forming biofilms in the respiratory tract. Despite extensive in vitro experimentation, how P. aeruginosa forms biofilms at the airway mucosa is unresolved. To investigate the process of biofilm formation in realistic conditions, we developed AirGels: 3D, optically accessible tissue-engineered human lung models that emulate the airway mucosal environment. AirGels recapitulate important factors that mediate host-pathogen interactions including mucus secretion, flow and air-liquid interface (ALI), while accommodating high-resolution live microscopy. With AirGels, we investigated the contributions of mucus to P. aeruginosa biofilm biogenesis in in vivo-like conditions. We found that P. aeruginosa forms mucus-associated biofilms within hours by contracting luminal mucus early during colonization. Mucus contractions facilitate aggregation, thereby nucleating biofilms. We show that P. aeruginosa actively contracts mucus using retractile filaments called type IV pili. Our results therefore suggest that, while protecting epithelia, mucus constitutes a breeding ground for biofilms.
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Affiliation(s)
- Tamara Rossy
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Tania Distler
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Lucas A Meirelles
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Joern Pezoldt
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jaemin Kim
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States of America
| | - Lorenzo Talà
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Nikolaos Bouklas
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, United States of America
| | - Bart Deplancke
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Alexandre Persat
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Manner C, Dias Teixeira R, Saha D, Kaczmarczyk A, Zemp R, Wyss F, Jaeger T, Laventie BJ, Boyer S, Malone JG, Qvortrup K, Andersen JB, Givskov M, Tolker-Nielsen T, Hiller S, Drescher K, Jenal U. A genetic switch controls Pseudomonas aeruginosa surface colonization. Nat Microbiol 2023; 8:1520-1533. [PMID: 37291227 DOI: 10.1038/s41564-023-01403-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 05/05/2023] [Indexed: 06/10/2023]
Abstract
Efficient colonization of mucosal surfaces is essential for opportunistic pathogens like Pseudomonas aeruginosa, but how bacteria collectively and individually adapt to optimize adherence, virulence and dispersal is largely unclear. Here we identified a stochastic genetic switch, hecR-hecE, which is expressed bimodally and generates functionally distinct bacterial subpopulations to balance P. aeruginosa growth and dispersal on surfaces. HecE inhibits the phosphodiesterase BifA and stimulates the diguanylate cyclase WspR to increase c-di-GMP second messenger levels and promote surface colonization in a subpopulation of cells; low-level HecE-expressing cells disperse. The fraction of HecE+ cells is tuned by different stress factors and determines the balance between biofilm formation and long-range cell dispersal of surface-grown communities. We also demonstrate that the HecE pathway represents a druggable target to effectively counter P. aeruginosa surface colonization. Exposing such binary states opens up new ways to control mucosal infections by a major human pathogen.
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Affiliation(s)
| | | | - Dibya Saha
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Fabian Wyss
- Biozentrum, University of Basel, Basel, Switzerland
| | - Tina Jaeger
- Biozentrum, University of Basel, Basel, Switzerland
- Department Biomedizin, University of Basel, Basel, Switzerland
| | | | - Sebastien Boyer
- sciCORE, Centre for Scientific Computing, University of Basel, Basel, Switzerland
| | - Jacob G Malone
- Biozentrum, University of Basel, Basel, Switzerland
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK
| | - Katrine Qvortrup
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Jens Bo Andersen
- Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Michael Givskov
- Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | - Urs Jenal
- Biozentrum, University of Basel, Basel, Switzerland.
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Sánchez-Jiménez A, Llamas MA, Marcos-Torres FJ. Transcriptional Regulators Controlling Virulence in Pseudomonas aeruginosa. Int J Mol Sci 2023; 24:11895. [PMID: 37569271 PMCID: PMC10418997 DOI: 10.3390/ijms241511895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
Pseudomonas aeruginosa is a pathogen capable of colonizing virtually every human tissue. The host colonization competence and versatility of this pathogen are powered by a wide array of virulence factors necessary in different steps of the infection process. This includes factors involved in bacterial motility and attachment, biofilm formation, the production and secretion of extracellular invasive enzymes and exotoxins, the production of toxic secondary metabolites, and the acquisition of iron. Expression of these virulence factors during infection is tightly regulated, which allows their production only when they are needed. This process optimizes host colonization and virulence. In this work, we review the intricate network of transcriptional regulators that control the expression of virulence factors in P. aeruginosa, including one- and two-component systems and σ factors. Because inhibition of virulence holds promise as a target for new antimicrobials, blocking the regulators that trigger the production of virulence determinants in P. aeruginosa is a promising strategy to fight this clinically relevant pathogen.
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Affiliation(s)
| | - María A. Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| | - Francisco Javier Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
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Geiger CJ, O’Toole GA. Evidence for the Type IV Pilus Retraction Motor PilT as a Component of the Surface Sensing System in Pseudomonas aeruginosa. J Bacteriol 2023; 205:e0017923. [PMID: 37382531 PMCID: PMC10367593 DOI: 10.1128/jb.00179-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/30/2023] Open
Abstract
Biofilm formation begins when bacteria contacting a surface induce cellular changes to become better adapted for surface growth. One of the first changes to occur for Pseudomonas aeruginosa after surface contact is an increase in the nucleotide second messenger 3',5'-cyclic AMP (cAMP). It has been demonstrated that this increase in intracellular cAMP is dependent on functional type IV pili (T4P) relaying a signal to the Pil-Chp system, but the mechanism by which this signal is transduced remains poorly understood. Here, we investigate the role of the type IV pilus retraction motor PilT in sensing a surface and relaying that signal to cAMP production. We show that mutations in PilT, and in particular those impacting the ATPase activity of this motor protein, reduce surface-dependent cAMP production. We identify a novel interaction between PilT and PilJ, a member of the Pil-Chp system, and propose a new model whereby P. aeruginosa uses its PilT retraction motor to sense a surface and to relay that signal via PilJ to increased production of cAMP. We discuss these findings in light of current T4P-dependent surface sensing models for P. aeruginosa. IMPORTANCE T4P are cellular appendages that allow P. aeruginosa to sense a surface, leading to the production of cAMP. This second messenger not only activates virulence pathways but leads to further surface adaptation and irreversible attachment of cells. Here, we demonstrate the importance of the retraction motor PilT in surface sensing. We also present a new surface sensing model in P. aeruginosa whereby the T4P retraction motor PilT senses and transmits the surface signal, likely via its ATPase domain and interaction with PilJ, to mediate production of the second messenger cAMP.
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Affiliation(s)
- C. J. Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - G. A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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36
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Bianco MI, Ponso MA, Garita-Cambronero J, Conforte VP, Galván TE, Dunger G, Morales GM, Vojnov AA, Romero AM, Cubero J, Yaryura PM. Genomic and phenotypic insight into Xanthomonas vesicatoria strains with different aggressiveness on tomato. Front Microbiol 2023; 14:1185368. [PMID: 37440880 PMCID: PMC10333488 DOI: 10.3389/fmicb.2023.1185368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023] Open
Abstract
Xanthomonas vesicatoria is one of the causal agents of bacterial spot, a disease that seriously affects the production of tomato (Solanum lycopersicum) and pepper (Capsicum annum) worldwide. In Argentina, bacterial spot is found in all tomato producing areas, with X. vesicatoria being one of the main species detected in the fields. Previously, we isolated three X. vesicatoria strains BNM 208, BNM 214, and BNM 216 from tomato plants with bacterial spot, and found they differed in their ability to form biofilm and in their degree of aggressiveness. Here, the likely causes of those differences were explored through genotypic and phenotypic studies. The genomes of the three strains were sequenced and assembled, and then compared with each other and also with 12 other publicly available X. vesicatoria genomes. Phenotypic characteristics (mainly linked to biofilm formation and virulence) were studied in vitro. Our results show that the differences observed earlier between BNM 208, BNM 214, and BNM 216 may be related to the structural characteristics of the xanthan gum produced by each strain, their repertoire of type III effectors (T3Es), the presence of certain genes associated with c-di-GMP metabolism and type IV pili (T4P). These findings on the pathogenicity mechanisms of X. vesicatoria could be useful for developing bacterial spot control strategies aimed at interfering with the infection processes.
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Affiliation(s)
- María Isabel Bianco
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - María Agustina Ponso
- Instituto Multidisciplinario de Investigación y Transferencia Agroalimentario y Biotecnológica (IMITAB, UNVM-CONICET), Instituto Académico Pedagógico de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María, Villa María, Argentina
| | | | - Valeria Paola Conforte
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - Tadeo E. Galván
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Germán Dunger
- Facultad de Ciencias Agrarias, Instituto de Ciencias Agropecuarias del Litoral, CONICET, Universidad Nacional del Litoral, Esperanza, Argentina
| | - Gustavo M. Morales
- Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados, Universidad Nacional de Rio Cuarto – CONICET, Rio Cuarto, Argentina
| | - Adrián Alberto Vojnov
- Instituto de Ciencia y Tecnología Dr. César Milstein – Fundación Pablo Cassará – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Investigación en Medicina y Ciencias de la Salud, Facultad de Medicina, Universidad del Salvador, Buenos Aires, Argentina
| | - Ana María Romero
- Cátedra de Fitopatología, Departamento de Producción Vegetal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jaime Cubero
- Laboratorio de Bacteriología, Departamento de Protección Vegetal, Instituto Nacional de Investigación y Tecnología Agraria/Consejo Superior de Investigaciones Científicas (INIA/CSIC), Madrid, Spain
| | - Pablo Marcelo Yaryura
- Instituto Multidisciplinario de Investigación y Transferencia Agroalimentario y Biotecnológica (IMITAB, UNVM-CONICET), Instituto Académico Pedagógico de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María, Villa María, Argentina
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37
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Scherhag A, Räschle M, Unbehend N, Venn B, Glueck D, Mühlhaus T, Keller S, Pérez Patallo E, Zehner S, Frankenberg-Dinkel N. Characterization of a soluble library of the Pseudomonas aeruginosa PAO1 membrane proteome with emphasis on c-di-GMP turnover enzymes. MICROLIFE 2023; 4:uqad028. [PMID: 37441524 PMCID: PMC10335732 DOI: 10.1093/femsml/uqad028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/30/2023] [Indexed: 07/15/2023]
Abstract
Studies of protein-protein interactions in membranes are very important to fully understand the biological function of a cell. The extraction of proteins from the native membrane environment is a critical step in the preparation of membrane proteins that might affect the stability of protein complexes. In this work, we used the amphiphilic diisobutylene/maleic acid copolymer to extract the membrane proteome of the opportunistic pathogen Pseudomonas aeruginosa, thereby creating a soluble membrane-protein library within a native-like lipid-bilayer environment. Size fractionation of nanodisc-embedded proteins and subsequent mass spectrometry enabled the identification of 3358 proteins. The native membrane-protein library showed a very good overall coverage compared to previous proteome data. The pattern of size fractionation indicated that protein complexes were preserved in the library. More than 20 previously described complexes, e.g. the SecYEG and Pili complexes, were identified and analyzed for coelution. Although the mass-spectrometric dataset alone did not reveal new protein complexes, combining pulldown assays with mass spectrometry was successful in identifying new protein interactions in the native membrane-protein library. Thus, we identified several candidate proteins for interactions with the membrane phosphodiesterase NbdA, a member of the c-di-GMP network. We confirmed the candidate proteins CzcR, PA4200, SadC, and PilB as novel interaction partners of NbdA using the bacterial adenylate cyclase two-hybrid assay. Taken together, this work demonstrates the usefulness of the native membrane-protein library of P. aeruginosa for the investigation of protein interactions and membrane-protein complexes. Data are available via ProteomeXchange with identifiers PXD039702 and PXD039700.
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Affiliation(s)
- Anna Scherhag
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Markus Räschle
- Department of Molecular Genetics, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Niklas Unbehend
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Benedikt Venn
- Department of Computational Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - David Glueck
- Department of Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Department of Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
- BioTechMed-Graz, Graz 8010, Austria
| | - Timo Mühlhaus
- Department of Computational Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Sandro Keller
- Department of Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Department of Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
- BioTechMed-Graz, Graz 8010, Austria
| | - Eugenio Pérez Patallo
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | | | - Nicole Frankenberg-Dinkel
- Corresponding author. RPTU Kaiserslautern-Landau, Microbiology, Kaiserslautern 67655, Germany. E-mail:
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de Sousa T, Hébraud M, Alves O, Costa E, Maltez L, Pereira JE, Martins Â, Igrejas G, Poeta P. Study of Antimicrobial Resistance, Biofilm Formation, and Motility of Pseudomonas aeruginosa Derived from Urine Samples. Microorganisms 2023; 11:1345. [PMID: 37317319 DOI: 10.3390/microorganisms11051345] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 04/28/2023] [Accepted: 05/17/2023] [Indexed: 06/16/2023] Open
Abstract
Pseudomonas aeruginosa causes urinary tract infections associated with catheters by forming biofilms on the surface of indwelling catheters. Therefore, controlling the spread of the bacteria is crucial to preventing its transmission in hospitals and the environment. Thus, our objective was to determine the antibiotic susceptibility profiles of twenty-five P. aeruginosa isolates from UTIs at the Medical Center of Trás-os-Montes and Alto Douro (CHTMAD). Biofilm formation and motility are also virulence factors studied in this work. Out of the twenty-five P. aeruginosa isolates, 16% exhibited multidrug resistance, being resistant to at least three classes of antibiotics. However, the isolates showed a high prevalence of susceptibility to amikacin and tobramycin. Resistance to carbapenem antibiotics, essential for treating infections when other antibiotics fail, was low in this study, Notably, 92% of the isolates demonstrated intermediate sensitivity to ciprofloxacin, raising concerns about its efficacy in controlling the disease. Genotypic analysis revealed the presence of various β-lactamase genes, with class B metallo-β-lactamases (MBLs) being the most common. The blaNDM, blaSPM, and blaVIM-VIM2 genes were detected in 16%, 60%, and 12% of the strains, respectively. The presence of these genes highlights the emerging threat of MBL-mediated resistance. Additionally, virulence gene analysis showed varying prevalence rates among the strains. The exoU gene, associated with cytotoxicity, was found in only one isolate, while other genes such as exoS, exoA, exoY, and exoT had a high prevalence. The toxA and lasB genes were present in all isolates, whereas the lasA gene was absent. The presence of various virulence genes suggests the potential of these strains to cause severe infections. This pathogen demonstrated proficiency in producing biofilms, as 92% of the isolates were found to be capable of doing so. Currently, antibiotic resistance is one of the most serious public health problems, as options become inadequate with the continued emergence and spread of multidrug-resistant strains, combined with the high rate of biofilm production and the ease of dissemination. In conclusion, this study provides insights into the antibiotic resistance and virulence profiles of P. aeruginosa strains isolated from human urine infections, highlighting the need for continued surveillance and appropriate therapeutic approaches.
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Affiliation(s)
- Telma de Sousa
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associate Laboratory for Green Chemistry (LAQV), Chemistry Department, Faculty of Science and Technology, University Nova of Lisbon, 2829-516 Lisbon, Portugal
| | - Michel Hébraud
- Université Clermont Auvergne, INRAE, UMR Microbiologie Environnement Digestif Santé (MEDiS), 60122 Saint-Genès-Champanelle, France
| | - Olimpia Alves
- Medical Centre of Trás-os-Montes and Alto Douro, Clinical Pathology Department, 5000-801 Vila Real, Portugal
| | - Eliana Costa
- Medical Centre of Trás-os-Montes and Alto Douro, Clinical Pathology Department, 5000-801 Vila Real, Portugal
| | - Luís Maltez
- Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
| | - José Eduardo Pereira
- Veterinary and Animal Research Centre (CECAV), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
| | - Ângela Martins
- Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Department of Zootechnics, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
| | - Gilberto Igrejas
- Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Functional Genomics and Proteomics Unit, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associate Laboratory for Green Chemistry (LAQV), Chemistry Department, Faculty of Science and Technology, University Nova of Lisbon, 2829-516 Lisbon, Portugal
| | - Patricia Poeta
- Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associate Laboratory for Green Chemistry (LAQV), Chemistry Department, Faculty of Science and Technology, University Nova of Lisbon, 2829-516 Lisbon, Portugal
- Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
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Solanki V, Tiwari M, Tiwari V. Investigation of Peptidoglycan-Associated Lipoprotein of Acinetobacter baumannii and Its Interaction with Fibronectin To Find Its Therapeutic Potential. Infect Immun 2023; 91:e0002323. [PMID: 37017535 PMCID: PMC10187120 DOI: 10.1128/iai.00023-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/07/2023] [Indexed: 04/06/2023] Open
Abstract
Acinetobacter baumannii causes hospital-acquired infections and is responsible for high mortality and morbidity. The interaction of this bacterium with the host is critical in bacterial pathogenesis and infection. Here, we report the interaction of peptidoglycan-associated lipoprotein (PAL) of A. baumannii with host fibronectin (FN) to find its therapeutic potential. The proteome of A. baumannii was explored in the host-pathogen interaction database to filter out the PAL of the bacterial outer membrane that interacts with the host's FN protein. This interaction was confirmed experimentally using purified recombinant PAL and pure FN protein. To investigate the pleiotropic role of PAL protein, different biochemical assays using wild-type PAL and PAL mutants were performed. The result showed that PAL mediates bacterial pathogenesis, adherence, and invasion in host pulmonary epithelial cells and has a role in the biofilm formation, bacterial motility, and membrane integrity of bacteria. All of the results suggest that PAL's interaction with FN plays a vital role in host-cell interaction. In addition, the PAL protein also interacts with Toll-like receptor 2 and MARCO receptor, which suggests the role of PAL protein in innate immune responses. We have also investigated the therapeutic potential of this protein for vaccine and therapeutic design. Using reverse vaccinology, PAL's potential epitopes were filtered out that exhibit binding potential with host major histocompatibility complex class I (MHC-I), MHC-II, and B cells, suggesting that PAL protein is a potential vaccine target. The immune simulation showed that PAL protein could elevate innate and adaptive immune response with the generation of memory cells and would have subsequent potential to eliminate bacterial infection. Therefore, the present study highlights the interaction ability of a novel host-pathogen interacting partner (PAL-FN) and uncovers its therapeutic potential to combat infection caused by A. baumannii.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
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Simsek AN, Koch MD, Sanfilippo JE, Gitai Z, Gompper G, Sabass B. Type-IV pili tune an adhesion-migration trade-off during surface colonization of Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.538458. [PMID: 37215001 PMCID: PMC10197611 DOI: 10.1101/2023.05.09.538458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bacterial pathogenicity relies on both firm surface adhesion and cell dissemination. How twitching bacteria resolve the fundamental contradiction between adhesion and migration is unknown. To address this question, we employ live-cell imaging of type-IV pili (T4P) and therewith construct a comprehensive mathematical model of Pseudomonas aeruginosa migration. The data show that only 10% to 50% of T4P bind to substrates and contribute to migration through random extension and retraction. Individual T4P do not display a measurable sensory response to surfaces, but their number increases on cellular surface contact. Attachment to surfaces is mediated, besides T4P, by passive adhesive forces acting on the cell body. Passive adhesions slow down cell migration and result in local random motion on short time scales, which is followed by directionally persistent, superdiffusive motion on longer time scales. Moreover, passive adhesions strongly enhance surface attachment under shear flow. Δ pilA mutants, which produce no T4P, robustly stick to surfaces under shear flow. In contrast, rapidly migrating Δ pilH cells, which produce an excessive number of T4P, are easily detached by shear. Wild-type cells sacrifice migration speed for robust surface attachment by maintaining a low number of active pili. The different cell strains pertain to disjunct regimes in a generic adhesion-migration trait space. Depending on the nature of the adhesion structures, adhesion and migration are either compatible or a trade-off is required for efficient bacterial surface colonization under different conditions.
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41
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Geiger CJ, O'Toole GA. Evidence for the Type IV Pili Retraction Motor PilT as a Component of the Surface Sensing System in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539127. [PMID: 37205505 PMCID: PMC10187167 DOI: 10.1101/2023.05.02.539127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Biofilm formation begins when bacteria contacting a surface induce cellular changes to become better adapted for surface growth. One of the first changes to occur for Pseudomonas aeruginosa after surface contact is an increase in the nucleotide second messenger 3',5'-cyclic adenosine monophosphate (cAMP). It has been demonstrated that this increase in intracellular cAMP is dependent on functional Type IV pili (T4P) relaying a signal to the Pil-Chp system, but the mechanism by which this signal is transduced remains poorly understood. Here, we investigate the role of the Type IV pili retraction motor PilT in sensing a surface and relaying that signal to cAMP production. We show that mutations affecting the structure of PilT and in particular ATPase activity of this motor protein, reduce surface-dependent cAMP production. We identify a novel interaction between PilT and PilJ, a member of the Pil-Chp system, and propose a new model whereby P. aeruginosa uses its retraction motor to sense a surface and to relay that signal via PilJ to increased production of cAMP. We discuss these findings in light of current TFP-dependent surface sensing models for P. aeruginosa . Importance T4P are cellular appendages that allow P. aeruginosa to sense a surface leading to the production of cAMP. This second messenger not only activates virulence pathways but leads to further surface adaptation and irreversible attachment of cells. Here, we demonstrate the importance of the retraction motor PilT in surface sensing. We also present a new surface sensing model in P. aeruginosa whereby the T4P retraction motor PilT senses and transmits the surface signal, likely via its ATPase domain and interaction with PilJ, to mediate production of the second messenger cAMP.
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Affiliation(s)
- C J Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth
| | - G A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth
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Rudzite M, Subramoni S, Endres RG, Filloux A. Effectiveness of Pseudomonas aeruginosa type VI secretion system relies on toxin potency and type IV pili-dependent interaction. PLoS Pathog 2023; 19:e1011428. [PMID: 37253075 PMCID: PMC10281587 DOI: 10.1371/journal.ppat.1011428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 06/20/2023] [Accepted: 05/17/2023] [Indexed: 06/01/2023] Open
Abstract
The type VI secretion system (T6SS) is an antibacterial weapon that is used by numerous Gram-negative bacteria to gain competitive advantage by injecting toxins into adjacent prey cells. Predicting the outcome of a T6SS-dependent competition is not only reliant on presence-absence of the system but instead involves a multiplicity of factors. Pseudomonas aeruginosa possesses 3 distinct T6SSs and a set of more than 20 toxic effectors with diverse functions including disruption of cell wall integrity, degradation of nucleic acids or metabolic impairment. We generated a comprehensive collection of mutants with various degrees of T6SS activity and/or sensitivity to each individual T6SS toxin. By imaging whole mixed bacterial macrocolonies, we then investigated how these P. aeruginosa strains gain a competitive edge in multiple attacker/prey combinations. We observed that the potency of single T6SS toxin varies significantly from one another as measured by monitoring the community structure, with some toxins acting better in synergy or requiring a higher payload. Remarkably the degree of intermixing between preys and attackers is also key to the competition outcome and is driven by the frequency of contact as well as the ability of the prey to move away from the attacker using type IV pili-dependent twitching motility. Finally, we implemented a computational model to better understand how changes in T6SS firing behaviours or cell-cell contacts lead to population level competitive advantages, thus providing conceptual insight applicable to all types of contact-based competition.
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Affiliation(s)
- Marta Rudzite
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Sujatha Subramoni
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Robert G. Endres
- Centre for Integrative Systems Biology and Bioinformatics, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
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Abstract
Bacteria thrive in environments rich in fluid flow, such as the gastrointestinal tract, bloodstream, aquatic systems, and the urinary tract. Despite the importance of flow, how flow affects bacterial life is underappreciated. In recent years, the combination of approaches from biology, physics, and engineering has led to a deeper understanding of how bacteria interact with flow. Here, we highlight the wide range of bacterial responses to flow, including changes in surface adhesion, motility, surface colonization, quorum sensing, virulence factor production, and gene expression. To emphasize the diversity of flow responses, we focus our review on how flow affects four ecologically distinct bacterial species: Escherichia coli, Staphylococcus aureus, Caulobacter crescentus, and Pseudomonas aeruginosa. Additionally, we present experimental approaches to precisely study bacteria in flow, discuss how only some flow responses are triggered by shear force, and provide perspective on flow-sensitive bacterial signaling.
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Affiliation(s)
- Gilberto C. Padron
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Alexander M. Shuppara
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jessica-Jae S. Palalay
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Anuradha Sharma
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Joseph E. Sanfilippo
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Blanco-Romero E, Durán D, Garrido-Sanz D, Redondo-Nieto M, Martín M, Rivilla R. Adaption of Pseudomonas ogarae F113 to the Rhizosphere Environment-The AmrZ-FleQ Hub. Microorganisms 2023; 11:microorganisms11041037. [PMID: 37110460 PMCID: PMC10146422 DOI: 10.3390/microorganisms11041037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Motility and biofilm formation are two crucial traits in the process of rhizosphere colonization by pseudomonads. The regulation of both traits requires a complex signaling network that is coordinated by the AmrZ-FleQ hub. In this review, we describe the role of this hub in the adaption to the rhizosphere. The study of the direct regulon of AmrZ and the phenotypic analyses of an amrZ mutant in Pseudomonas ogarae F113 has shown that this protein plays a crucial role in the regulation of several cellular functions, including motility, biofilm formation, iron homeostasis, and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, controlling the synthesis of extracellular matrix components. On the other hand, FleQ is the master regulator of flagellar synthesis in P. ogarae F113 and other pseudomonads, but its implication in the regulation of multiple traits related with environmental adaption has been shown. Genomic scale studies (ChIP-Seq and RNA-Seq) have shown that in P. ogarae F113, AmrZ and FleQ are general transcription factors that regulate multiple traits. It has also been shown that there is a common regulon shared by the two transcription factors. Moreover, these studies have shown that AmrZ and FleQ form a regulatory hub that inversely regulate traits such as motility, extracellular matrix component production, and iron homeostasis. The messenger molecule c-di-GMP plays an essential role in this hub since its production is regulated by AmrZ and it is sensed by FleQ and required for its regulatory role. This regulatory hub is functional both in culture and in the rhizosphere, indicating that the AmrZ-FleQ hub is a main player of P. ogarae F113 adaption to the rhizosphere environment.
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Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
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Kühn MJ, Macmillan H, Talà L, Inclan Y, Patino R, Pierrat X, Al‐Mayyah Z, Engel JN, Persat A. Two antagonistic response regulators control Pseudomonas aeruginosa polarization during mechanotaxis. EMBO J 2023; 42:e112165. [PMID: 36795017 PMCID: PMC10519157 DOI: 10.15252/embj.2022112165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa adapts to solid surfaces to enhance virulence and infect its host. Type IV pili (T4P), long and thin filaments that power surface-specific twitching motility, allow single cells to sense surfaces and control their direction of movement. T4P distribution is polarized to the sensing pole by the chemotaxis-like Chp system via a local positive feedback loop. However, how the initial spatially resolved mechanical signal is translated into T4P polarity is incompletely understood. Here, we demonstrate that the two Chp response regulators PilG and PilH enable dynamic cell polarization by antagonistically regulating T4P extension. By precisely quantifying the localization of fluorescent protein fusions, we show that phosphorylation of PilG by the histidine kinase ChpA controls PilG polarization. Although PilH is not strictly required for twitching reversals, it becomes activated upon phosphorylation and breaks the local positive feedback mechanism established by PilG, allowing forward-twitching cells to reverse. Chp thus uses a main output response regulator, PilG, to resolve mechanical signals in space and employs a second regulator, PilH, to break and respond when the signal changes. By identifying the molecular functions of two response regulators that dynamically control cell polarization, our work provides a rationale for the diversity of architectures often found in non-canonical chemotaxis systems.
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Affiliation(s)
- Marco J Kühn
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | | | - Lorenzo Talà
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Yuki Inclan
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
| | - Ramiro Patino
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
| | - Xavier Pierrat
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Zainebe Al‐Mayyah
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Joanne N Engel
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
- Department of Microbiology and ImmunologyUniversity of CaliforniaSan FranciscoCAUSA
| | - Alexandre Persat
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
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46
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Nguyen VH, Wemheuer B, Song W, Bennett H, Palladino G, Burgsdorf I, Sizikov S, Steindler L, Webster NS, Thomas T. Functional characterization and taxonomic classification of novel gammaproteobacterial diversity in sponges. Syst Appl Microbiol 2023; 46:126401. [PMID: 36774720 DOI: 10.1016/j.syapm.2023.126401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 01/18/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
Sponges harbour exceptionally diverse microbial communities, whose members are largely uncultured. The class Gammaproteobacteria often dominates the microbial communities of various sponge species, but most of its diversity remains functional and taxonomically uncharacterised. Here we reconstructed and characterised 32 metagenome-assembled genomes (MAGs) derived from three sponge species. These MAGs represent ten novel species and belong to seven orders, of which one is new. We propose nomenclature for all these taxa. These new species comprise sponge-specific bacteria with varying levels of host specificity. Functional gene profiling highlights significant differences in metabolic capabilities across the ten species, though each also often exhibited a large degree of metabolic diversity involving various nitrogen- and sulfur-based compounds. The genomic features of the ten species suggest they have evolved to form symbiotic interaction with their hosts or are well-adapted to survive within the sponge environment. These Gammaproteobacteria are proposed to scavenge substrates from the host environment, including metabolites or cellular components of the sponge. Their diverse metabolic capabilities may allow for efficient cycling of organic matter in the sponge environment, potentially to the benefit of the host and other symbionts.
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Affiliation(s)
- Viet Hung Nguyen
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Bernd Wemheuer
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Weizhi Song
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Holly Bennett
- Australian Institute of Marine Science, Townsville, Queensland, Australia; Cawthron Institute, Nelson, New Zealand
| | - Giorgia Palladino
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia; Unit of Microbiome Science and Biotechnology, Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | | | | | | | - Nicole S Webster
- Australian Institute of Marine Science, Townsville, Queensland, Australia; Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia; Australian Antarctic Division, Kingston, Tasmania, Australia
| | - Torsten Thomas
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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47
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Dou Q, Zhu Y, Li C, Bian Z, Song H, Zhang R, Wang Y, Zhang X, Wang Y. 4F-Indole Enhances the Susceptibility of Pseudomonas aeruginosa to Aminoglycoside Antibiotics. Microbiol Spectr 2023; 11:e0451922. [PMID: 36975825 PMCID: PMC10100892 DOI: 10.1128/spectrum.04519-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
Infections caused by multidrug-resistant bacteria are becoming increasingly serious. The aminoglycoside antibiotics have been widely used to treat severe Gram-negative bacterial infections. Here, we reported that a class of small molecules, namely, halogenated indoles, can resensitize Pseudomonas aeruginosa PAO1 to aminoglycoside antibiotics such as gentamicin, kanamycin, tobramycin, amikacin, neomycin, ribosomalin sulfate, and cisomicin. We selected 4F-indole as a representative of halogenated indoles to investigate its mechanism and found that the two-component system (TCS) PmrA/PmrB inhibited the expression of multidrug efflux pump MexXY-OprM, allowing kanamycin to act intracellularly. Moreover, 4F-indole inhibited the biosynthesis of several virulence factors, such as pyocyanin, type III secretion system (T3SS), and type VI secretion system (T6SS) exported effectors, and reduced the swimming and twitching motility by suppressing the expression of flagella and type IV pili. This study suggests that the combination of 4F-indole and kanamycin can be more effective against P. aeruginosa PAO1 and affect its multiple physiological activities, providing a novel insight into the reactivation of aminoglycoside antibiotics. IMPORTANCE Infections caused by Pseudomonas aeruginosa have become a major public health crisis. Its resistance to existing antibiotics causes clinical infections that are hard to cure. In this study, we found that halogenated indoles in combination with aminoglycoside antibiotics could be more effective than antibiotics alone against P. aeruginosa PAO1 and preliminarily revealed the mechanism of the 4F-indole-induced regulatory effect. Moreover, the regulatory effect of 4F-indole on different physiological behaviors of P. aeruginosa PAO1 was analyzed by combined transcriptomics and metabolomics. We explain that 4F-indole has potential as a novel antibiotic adjuvant, thus slowing down the further development of bacterial resistance.
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Affiliation(s)
- Qin Dou
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yuxiang Zhu
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Chunhui Li
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Zeran Bian
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Huihui Song
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Ruizhen Zhang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yingsong Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xile Zhang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yan Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
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48
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Material Substrate Physical Properties Control Pseudomonas aeruginosa Biofilm Architecture. mBio 2023; 14:e0351822. [PMID: 36786569 PMCID: PMC10127718 DOI: 10.1128/mbio.03518-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
In the wild, bacteria are most frequently found in the form of multicellular structures called biofilms. Biofilms grow at the surface of abiotic and living materials with wide-ranging mechanical properties. The opportunistic pathogen Pseudomonas aeruginosa forms biofilms on indwelling medical devices and on soft tissues, including burn wounds and the airway mucosa. Despite the critical role of substrates in the foundation of biofilms, we still lack a clear understanding of how material mechanics regulate their architecture and the physiology of resident bacteria. Here, we demonstrate that physical properties of hydrogel material substrates define P. aeruginosa biofilm architecture. We show that hydrogel mesh size regulates twitching motility, a surface exploration mechanism priming biofilms, ultimately controlling the organization of single cells in the multicellular community. The resulting architectural transitions increase P. aeruginosa's tolerance to colistin, a last-resort antibiotic. In addition, mechanical regulation of twitching motility affects P. aeruginosa clonal lineages, so that biofilms are more mixed on relatively denser materials. Our results thereby establish material properties as a factor that dramatically affects biofilm architecture, antibiotic efficacy, and evolution of the resident population. IMPORTANCE The biofilm lifestyle is the most widespread survival strategy in the bacterial world. Pseudomonas aeruginosa biofilms cause chronic infections and are highly recalcitrant to antimicrobials. The genetic requirements allowing P. aeruginosa to grow into biofilms are known, but not the physical stimuli that regulate their formation. Despite colonizing biological tissues, investigations of biofilms on soft materials are limited. In this work, we show that biofilms take unexpected forms when growing on soft substrates. The physical properties of the material shape P. aeruginosa biofilms by regulating surface-specific twitching motility. Physical control of biofilm morphogenesis ultimately influences the resilience of biofilms to antimicrobials, linking physical environment with tolerance to treatment. Altogether, our work established that the physical properties of a surface are a critical environmental regulator of biofilm biogenesis and evolution.
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49
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Memariani H, Memariani M. Antibiofilm properties of cathelicidin LL-37: an in-depth review. World J Microbiol Biotechnol 2023; 39:99. [PMID: 36781570 DOI: 10.1007/s11274-023-03545-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/08/2023] [Indexed: 02/15/2023]
Abstract
Notwithstanding ceaseless endeavors toward developing effective antibiofilm chemotherapeutics, biofilm-associated infections continue to be one of the most perplexing challenges confronting medicine today. Endogenous host defense peptides, such as the human cathelicidin LL-37, are being propounded as promising options for treating such infectious diseases. Over the past decennium, LL-37 has duly received tremendous research attention by virtue of its broad-spectrum antimicrobial activity and immunomodulatory properties. No attempt has hitherto been made, as far as we are aware, to comprehensively review the antibiofilm effects of LL-37. Accordingly, the intent in this paper is to provide a fairly all-embracing review of the literature available on the subject. Accumulating evidence suggests that LL-37 is able to prevent biofilm establishment by different bacterial pathogens such as Acinetobacter baumannii, Aggregatibacter actinomycetemcomitans, Bacteroides fragilis, Burkholderia thailandensis, Cutibacterium acnes, Escherichia coli, Francisella tularensis, Helicobacter pylori, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes. Inhibition of bacterial adhesion, downregulation of biofilm-associated genes, suppression of quorum-sensing pathways, degradation of biofilm matrix, and eradication of biofilm-residing cells are the major mechanisms responsible for antibiofilm properties of LL-37. In terms of its efficacy and safety in vivo, there are still many questions to be answered. Undoubtedly, LL-37 can open up new windows of opportunity to prevent and treat obstinate biofilm-mediated infections.
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Affiliation(s)
- Hamed Memariani
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mojtaba Memariani
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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50
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Merfa MV, Zhu X, Shantharaj D, Gomez LM, Naranjo E, Potnis N, Cobine PA, De La Fuente L. Complete functional analysis of type IV pilus components of a reemergent plant pathogen reveals neofunctionalization of paralog genes. PLoS Pathog 2023; 19:e1011154. [PMID: 36780566 PMCID: PMC9956873 DOI: 10.1371/journal.ppat.1011154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/24/2023] [Accepted: 01/26/2023] [Indexed: 02/15/2023] Open
Abstract
Type IV pilus (TFP) is a multifunctional bacterial structure involved in twitching motility, adhesion, biofilm formation, as well as natural competence. Here, by site-directed mutagenesis and functional analysis, we determined the phenotype conferred by each of the 38 genes known to be required for TFP biosynthesis and regulation in the reemergent plant pathogenic fastidious prokaryote Xylella fastidiosa. This pathogen infects > 650 plant species and causes devastating diseases worldwide in olives, grapes, blueberries, and almonds, among others. This xylem-limited, insect-transmitted pathogen lives constantly under flow conditions and therefore is highly dependent on TFP for host colonization. In addition, TFP-mediated natural transformation is a process that impacts genomic diversity and environmental fitness. Phenotypic characterization of the mutants showed that ten genes were essential for both movement and natural competence. Interestingly, seven sets of paralogs exist, and mutations showed opposing phenotypes, indicating evolutionary neofunctionalization of subunits within TFP. The minor pilin FimT3 was the only protein exclusively required for natural competence. By combining approaches of molecular microbiology, structural biology, and biochemistry, we determined that the minor pilin FimT3 (but not the other two FimT paralogs) is the DNA receptor in TFP of X. fastidiosa and constitutes an example of neofunctionalization. FimT3 is conserved among X. fastidiosa strains and binds DNA non-specifically via an electropositive surface identified by homolog modeling. This protein surface includes two arginine residues that were exchanged with alanine and shown to be involved in DNA binding. Among plant pathogens, fimT3 was found in ~ 10% of the available genomes of the plant associated Xanthomonadaceae family, which are yet to be assessed for natural competence (besides X. fastidiosa). Overall, we highlight here the complex regulation of TFP in X. fastidiosa, providing a blueprint to understand TFP in other bacteria living under flow conditions.
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Affiliation(s)
- Marcus V. Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Xinyu Zhu
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Deepak Shantharaj
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Laura M. Gomez
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Eber Naranjo
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - Paul A. Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
- * E-mail:
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