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Environmental Microbiology Sep 2023Pseudomonads are considered to be among the most widespread culturable bacteria in mesophilic environments. The evolutive success of Pseudomonas species can be... (Review)
Review
Pseudomonads are considered to be among the most widespread culturable bacteria in mesophilic environments. The evolutive success of Pseudomonas species can be attributed to their metabolic versatility, in combination with a set of additional functions that enhance their ability to colonize different niches. These include the production of secondary metabolites involved in iron acquisition or having a detrimental effect on potential competitors, different types of motility, and the capacity to establish and persist within biofilms. Although biofilm formation has been extensively studied using the opportunistic pathogen Pseudomonas aeruginosa as a model organism, a significant body of knowledge is also becoming available for non-pathogenic Pseudomonas. In this review, we focus on the mechanisms that allow Pseudomonas putida to colonize biotic and abiotic surfaces and adapt to sessile life, as a relevant persistence strategy in the environment. This species is of particular interest because it includes plant-beneficial strains, in which colonization of plant surfaces may be relevant, and strains used for environmental and biotechnological applications, where the design and functionality of biofilm-based bioreactors, for example, also have to take into account the efficiency of bacterial colonization of solid surfaces. This work reviews the current knowledge of mechanistic and regulatory aspects of biofilm formation by P. putida and pinpoints the prospects in this field.
Topics: Pseudomonas putida; Pseudomonas; Biofilms; Pseudomonas aeruginosa; Plants
PubMed: 37045787
DOI: 10.1111/1462-2920.16385 -
BMC Microbiology Aug 2023Biofilm formation has reported as an important virulence associated properties of Pseudomonas aeruginosa that is regulated by quorum-sensing associated genes. Biofilm...
BACKGROUND
Biofilm formation has reported as an important virulence associated properties of Pseudomonas aeruginosa that is regulated by quorum-sensing associated genes. Biofilm and quorum-sensing interfering properties of steroidal alkaloids, Solanidine and Solasodine were investigated in the present study.
RESULTS
Biofilm formation capacity and relative expression level of five studied genes(lasI, lasR, rhlI, rhlR and algD) were significantly increased dose-dependently after treatment with sub-inhibitory concentrations (32 and 512 µg/ml) of the both Solanidine and Solasodine. Biofilm formation capacity was more stimulated in weak biofilm formers(9 iaolates) in comparison to the strong biofilm producers(11 isolates). The lasI gene was the most induced QS-associated gene among five investigated genes.
CONCLUSION
Biofilm inducing properties of the plants alkaloids and probably medicines derived from them has to be considered for revision of therapeutic guidelines. Investigating the biofilm stimulating properties of corticosteroids and other medicines that comes from plant alkaloids also strongly proposed.
Topics: Pseudomonas aeruginosa; Biofilms; Quorum Sensing; Virulence Factors; Bacterial Proteins
PubMed: 37533040
DOI: 10.1186/s12866-023-02957-z -
Viruses Nov 2023Therapeutic bacteriophages (phages) are primarily chosen based on their in vitro bacteriolytic activity. Although anti-phage antibodies are known to inhibit phage...
Therapeutic bacteriophages (phages) are primarily chosen based on their in vitro bacteriolytic activity. Although anti-phage antibodies are known to inhibit phage infection, the influence of other immune system components is less well known. An important anti-bacterial and anti-viral innate immune system that may interact with phages is the complement system, a cascade of proteases that recognizes and targets invading microorganisms. In this research, we aimed to study the effects of serum components such as complement on the infectivity of different phages targeting . We used a fluorescence-based assay to monitor the killing of by phages of different morphotypes in the presence of human serum. Our results reveal that several myophages are inhibited by serum in a concentration-dependent way, while the activity of four podophages and one siphophage tested in this study is not affected by serum. By using specific nanobodies blocking different components of the complement cascade, we showed that activation of the classical complement pathway is a driver of phage inhibition. To determine the mechanism of inhibition, we produced bioorthogonally labeled fluorescent phages to study their binding by means of microscopy and flow cytometry. We show that phage adsorption is hampered in the presence of active complement. Our results indicate that interactions with complement may affect the in vivo activity of therapeutically administered phages. A better understanding of this phenomenon is essential to optimize the design and application of therapeutic phage cocktails.
Topics: Humans; Pseudomonas aeruginosa; Pseudomonas Phages; Bacteriophages; Bacteriolysis; Pseudomonas Infections
PubMed: 38005888
DOI: 10.3390/v15112211 -
Journal of Biomedical Materials... Oct 2023Despite the promise of antimicrobial peptides (AMPs) as treatments for antibiotic-resistant infections, their therapeutic efficacy is limited due to the rapid...
Despite the promise of antimicrobial peptides (AMPs) as treatments for antibiotic-resistant infections, their therapeutic efficacy is limited due to the rapid degradation and low bioavailability of AMPs. To address this, we have developed and characterized a synthetic mucus (SM) biomaterial capable of delivering LL37 AMPs and enhancing their therapeutic effect. LL37 is an AMP that exhibits a wide range of antimicrobial activity against bacteria, including Pseudomonas aeruginosa. LL37 loaded SM hydrogels demonstrated controlled release with 70%-95% of loaded LL37 over 8 h due to charge-mediated interactions between mucins and LL37 AMPs. Compared to treatment with LL37 alone where antimicrobial activity was reduced after 3 h, LL37-SM hydrogels inhibited P. aeruginosa (PAO1) growth over 12 h. LL37-SM hydrogel treatment reduced PAO1 viability over 6 h whereas a rebound in bacterial growth was observed when treated with LL37 only. These data demonstrate LL37-SM hydrogels enhance antimicrobial activity by preserving LL37 AMP activity and bioavailability. Overall, this work establishes SM biomaterials as a platform for enhanced AMP delivery for antimicrobial applications.
Topics: Antimicrobial Peptides; Hydrogels; Mucus; Drug Delivery Systems; Pseudomonas aeruginosa
PubMed: 37199137
DOI: 10.1002/jbm.a.37559 -
Methods in Molecular Biology (Clifton,... 2024Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial infections and associated with lung infections in cystic fibrosis (CF) patients (Lyczak et al.,...
Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial infections and associated with lung infections in cystic fibrosis (CF) patients (Lyczak et al., Microbes Infect 2:1051-1060, 2000). Multiple drug-resistant P. aeruginosa strains pose a serious problem because of antibiotic treatment failure. There is therefore a need for alternative anti-Pseudomonas molecules. Soluble pyocins (S-pyocins) are bacteriocins produced by P. aeruginosa strains that kill sensitive strains of the same species. These bacteriocins and their immunity gene are easily cloned and expressed in E. coli and their activity spectrum against different P. aeruginosa strains can be tested. In this chapter, we describe the procedures for cloning, expression, and sensitivity testing of two different S-pyocins. We also describe how to identify their receptor binding domain in sensitive strains, how to construct chimeric pyocins with extended activity spectra, and how to identify new pyocins in genomes by multiplex PCR.
Topics: Humans; Pyocins; Pseudomonas aeruginosa; Escherichia coli; Bacteriocins; Anti-Bacterial Agents; Pseudomonas Infections
PubMed: 37819519
DOI: 10.1007/978-1-0716-3473-8_9 -
Proceedings of the National Academy of... Oct 2023Energy conversion by electron transport chains occurs through the sequential transfer of electrons between protein complexes and intermediate electron carriers, creating...
Energy conversion by electron transport chains occurs through the sequential transfer of electrons between protein complexes and intermediate electron carriers, creating the proton motive force that enables ATP synthesis and membrane transport. These protein complexes can also form higher order assemblies known as respiratory supercomplexes (SCs). The electron transport chain of the opportunistic pathogen is closely linked with its ability to invade host tissue, tolerate harsh conditions, and resist antibiotics but is poorly characterized. Here, we determine the structure of a SC that forms between the quinol:cytochrome oxidoreductase (cytochrome ) and one of the organism's terminal oxidases, cytochrome , which is found only in some bacteria. Remarkably, the SC structure also includes two intermediate electron carriers: a diheme cytochrome and a single heme cytochrome . Together, these proteins allow electron transfer from ubiquinol in cytochrome to oxygen in cytochrome . We also present evidence that different isoforms of cytochrome can participate in formation of this SC without changing the overall SC architecture. Incorporating these different subunit isoforms into the SC would allow the bacterium to adapt to different environmental conditions. Bioinformatic analysis focusing on structural motifs in the SC suggests that cytochrome - SCs also exist in other bacterial pathogens.
Topics: Pseudomonas aeruginosa; Electron Transport; Biological Transport; Cytochromes c; Anti-Bacterial Agents
PubMed: 37751552
DOI: 10.1073/pnas.2307093120 -
International Journal of... 2024Chromium (Cr) contamination of soil has substantially deteriorated soil health and has interfered with sustainable agricultural production worldwide and therefore, its...
Chromium (Cr) contamination of soil has substantially deteriorated soil health and has interfered with sustainable agricultural production worldwide and therefore, its remediation is inevitable. Inoculation of plant growth promoting rhizobacteria (PGPR) in association with nanotechnology has exerted broad based impacts in agriculture, and there is an urgent need to exploit their synergism in contaminated soils. Here, we investigated the effect of co-application of Cr-tolerant " CKQ9" strain and nano zerovalent iron (nZVI) in improving the phytoremediation potential of aloe vera ( L.) under Cr contamination. Soil was contaminated by using potassium dichromate (KCrO) salt and 15 mg kg contamination level in soil was maintained spiking and exposure to Cr lasted throughout the duration of the experiment (120 days). We observed that the co-application alleviated the adverse impacts of Cr on aloe vera, and improved various plant attributes such as plant height, root area, number of leaves and gel contents by 51, 137, 67 and 49% respectively as compared to control treatment under Cr contamination. Similarly, significant boost in the activities of various antioxidants including catalase (124%), superoxide dismutase (87%), ascorbate peroxidase (36%), peroxidase (89%) and proline (34%) was pragmatic under contaminated soil conditions. In terms of soil Cr concentration and its plant uptake, co-application of and nZVI also reduced available Cr concentration in soil (50%), roots (77%) and leaves (84%), while simultaneously increasing the relative production index by 225% than un-inoculated control. Hence, integrating PGPR with nZVI can be an effective strategy for enhancing the phytoremediation potential of aloe vera.
Topics: Aloe; Chromium; Biodegradation, Environmental; Iron; Soil Pollutants; Pseudomonas aeruginosa
PubMed: 38488053
DOI: 10.1080/15226514.2024.2327838 -
Proceedings of the National Academy of... Jul 2023The outer membrane of Gram-negative bacteria is unique in both structure and function. The surface-exposed outer leaflet is composed of lipopolysaccharide, while the...
The outer membrane of Gram-negative bacteria is unique in both structure and function. The surface-exposed outer leaflet is composed of lipopolysaccharide, while the inner leaflet is composed of glycerophospholipids. This lipid asymmetry creates mechanical strength, lowers membrane permeability, and is necessary for virulence in many pathogens. Glycerophospholipids that mislocalize to the outer leaflet are removed by the Mla pathway, which consists of the outer membrane channel MlaA, the periplasmic lipid carrier MlaC, and the inner membrane transporter MlaBDEF. The opportunistic pathogen has two proteins of the MlaA family: PA2800 and PA3239. Here, we show that PA2800 is part of a canonical Mla pathway, while PA3239 functions with the putative lipase PA3238. While loss of either pathway individually has little to no effect on outer membrane integrity, loss of both pathways weakens the outer membrane permeability barrier and increases production of the secondary metabolite pyocyanin. We propose that mislocalized glycerophospholipids are removed from the outer leaflet by PA3239 (renamed MlaZ), transferred to PA3238 (renamed MlaY), and degraded. This pathway streamlines recycling of glycerophospholipid degradation products by removing glycerophospholipids from the outer leaflet prior to degradation.
Topics: Membrane Lipids; Pseudomonas aeruginosa; Biological Transport; Phospholipases; Bacterial Outer Membrane Proteins; Cell Membrane; Glycerophospholipids
PubMed: 37463202
DOI: 10.1073/pnas.2302546120 -
Nature Communications Sep 2023Chronic infection with the bacterial pathogen Pseudomonas aeruginosa often leads to coexistence of heterogeneous populations carrying diverse mutations. In particular,...
Chronic infection with the bacterial pathogen Pseudomonas aeruginosa often leads to coexistence of heterogeneous populations carrying diverse mutations. In particular, loss-of-function mutations affecting the quorum-sensing regulator LasR are often found in bacteria isolated from patients with lung chronic infection and cystic fibrosis. Here, we study the evolutionary dynamics of polymorphic P. aeruginosa populations using isolates longitudinally collected from patients with chronic obstructive pulmonary disease (COPD). We find that isolates deficient in production of different sharable extracellular products are sequentially selected in COPD airways, and lasR mutants appear to be selected first due to their quorum-sensing defects. Polymorphic populations including lasR mutants display survival advantages in animal models of infection and modulate immune responses. Our study sheds light on the multistage evolution of P. aeruginosa populations during their adaptation to host lungs.
Topics: Animals; Humans; Pseudomonas aeruginosa; Persistent Infection; Pulmonary Disease, Chronic Obstructive; Cystic Fibrosis; Lung
PubMed: 37749088
DOI: 10.1038/s41467-023-41704-w -
Nature Protocols Nov 2023Much of our current understanding of microbiology is based on the application of genetic engineering procedures. Since their inception (more than 30 years ago), methods... (Review)
Review
Much of our current understanding of microbiology is based on the application of genetic engineering procedures. Since their inception (more than 30 years ago), methods based largely on allelic exchange and two-step selection processes have become a cornerstone of contemporary bacterial genetics. While these tools are established for adapted laboratory strains, they have limited applicability in clinical or environmental isolates displaying a large and unknown genetic repertoire that are recalcitrant to genetic modifications. Hence, new tools allowing genetic engineering of intractable bacteria must be developed to gain a comprehensive understanding of them in the context of their biological niche. Herein, we present a method for precise, efficient and rapid engineering of the opportunistic pathogen Pseudomonas aeruginosa. This procedure relies on recombination of short single-stranded DNA facilitated by targeted double-strand DNA breaks mediated by a synthetic Cas9 coupled with the efficient Ssr recombinase. Possible applications include introducing single-nucleotide polymorphisms, short or long deletions, and short DNA insertions using synthetic single-stranded DNA templates, drastically reducing the need of PCR and cloning steps. Our toolkit is encoded on two plasmids, harboring an array of different antibiotic resistance cassettes; hence, this approach can be successfully applied to isolates displaying natural antibiotic resistances. Overall, this toolkit substantially reduces the time required to introduce a range of genetic manipulations to a minimum of five experimental days, and enables a variety of research and biotechnological applications in both laboratory strains and difficult-to-manipulate P. aeruginosa isolates.
Topics: CRISPR-Cas Systems; Pseudomonas aeruginosa; DNA, Single-Stranded; Gene Editing; Genetic Engineering
PubMed: 37798358
DOI: 10.1038/s41596-023-00882-z