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The ISME Journal Jan 2024The role of antagonistic secondary metabolites produced by Pseudomonas protegens in suppression of soil-borne phytopathogens has been clearly documented. However, their...
The role of antagonistic secondary metabolites produced by Pseudomonas protegens in suppression of soil-borne phytopathogens has been clearly documented. However, their contribution to the ability of P. protegens to establish in soil and rhizosphere microbiomes remains less clear. Here, we use a four-species synthetic community (SynCom) in which individual members are sensitive towards key P. protegens antimicrobial metabolites (DAPG, pyoluteorin, and orfamide A) to determine how antibiotic production contributes to P. protegens community invasion and to identify community traits that counteract the antimicrobial effects. We show that P. protegens readily invades and alters the SynCom composition over time, and that P. protegens establishment requires production of DAPG and pyoluteorin. An orfamide A-deficient mutant of P. protegens invades the community as efficiently as wildtype, and both cause similar perturbations to community composition. Here, we identify the microbial interactions underlying the absence of an orfamide A mediated impact on the otherwise antibiotic-sensitive SynCom member, and show that the cyclic lipopeptide is inactivated and degraded by the combined action of Rhodococcus globerulus D757 and Stenotrophomonas indicatrix D763. Altogether, the demonstration that the synthetic community constrains P. protegens invasion by detoxifying its antibiotics may provide a mechanistic explanation to inconsistencies in biocontrol effectiveness in situ.
Topics: Pseudomonas; Soil Microbiology; Secondary Metabolism; Biotransformation; Rhizosphere; Microbiota; Microbial Interactions; Anti-Bacterial Agents; Phenols; Phloroglucinol; Pyrroles
PubMed: 38874164
DOI: 10.1093/ismejo/wrae105 -
Microbial Cell Factories Jun 2024Bacterial infections and the rising antimicrobial resistance pose a significant threat to public health. Pseudomonas aeruginosa produces bacteriocins like pyocins,...
INTRODUCTION
Bacterial infections and the rising antimicrobial resistance pose a significant threat to public health. Pseudomonas aeruginosa produces bacteriocins like pyocins, especially S-type pyocins, which are promising for biological applications. This research focuses on clinical P. aeruginosa isolates to assess their bacteriocin production, inhibitory spectrum, chemical structure, antibacterial agents, and preservative potential.
METHODS
The identification of P. aeruginosa was conducted through both phenotypic and molecular approaches. The inhibitory spectrum and antibacterial potential of the isolates were assessed. The kinetics of antibacterial peptide production were investigated, and the activity of bacteriocin was quantified in arbitrary units (AU ml). Physico-chemical characterization of the antibacterial peptides was performed. Molecular weight estimation was carried out using SDS-PAGE. qRT-PCR analysis was employed to validate the expression of the selected candidate gene.
RESULT
The antibacterial activity of P. aeruginosa was attributed to the secretion of bacteriocin compounds, which belong to the S-type pyocin family. The use of mitomycin C led to a significant 65.74% increase in pyocin production by these isolates. These S-type pyocins exhibited the ability to inhibit the growth of both Gram-negative (P. mirabilis and P. vulgaris) and Gram-positive (S. aureus, S. epidermidis, E. hirae, S. pyogenes, and S. mutans) bacteria. The molecular weight of S-type pyocin was 66 kDa, and its gene expression was confirmed through qRT-PCR.
CONCLUSION
These findings suggest that S-type pyocin hold significant potential as therapeutic agents against pathogenic strains. The Physico-chemical resistance of S-type pyocin underscores its potential for broad applications in the pharmaceutical, hygiene, and food industries.
Topics: Pseudomonas aeruginosa; Anti-Bacterial Agents; Bacteriocins; Microbial Sensitivity Tests; Pyocins; Humans; Pseudomonas Infections
PubMed: 38872163
DOI: 10.1186/s12934-024-02450-w -
Scientific Reports Jun 2024A novel nano bio-fertilizer encapsulation method was developed to crosslink chitosan and alginate with humic acid. These nanocapsules, referred to as (Ch./Alg.HA.NPK) or...
A novel nano bio-fertilizer encapsulation method was developed to crosslink chitosan and alginate with humic acid. These nanocapsules, referred to as (Ch./Alg.HA.NPK) or (Ch./Alg.HA.NPK.PGPRs), were loaded with nanoscale essential agro-nutrients (NPK) and beneficial microorganisms Pseudomonas Fluorescence abbreviated as (P.Fluorescence). Structural and morphological analyses were conducted using FourierTransform Infrared, Thermogravimetric Analysis, Scanning Electron Microscopy, Malvern Zeta NanoSizer, and Zeta potential. Encapsulation efficiency and water retention were also determined compared to control non-crosslinked nanocapsules. The sustained cumulative release of NPK over 30 days was also investigated to 33.2%, 47.8%, and 68.3%, alternatively. The release mechanism, also assessed through the kinetic module of the Korsemeyer- Peppas Mathematical model, demonstrated superior performance compared to non-crosslinked nanocapsules (chitosan/alginate). These results show the potential of the synthesized nanocapsules for environmentally conscious controlled release of NPK and PGPRs, thereby mitigating environmental impact, enhancing plant growth, and reducing reliance on conventional agrochemical fertilizers.
Topics: Fertilizers; Chitosan; Agriculture; Alginates; Nanocapsules; Humic Substances; Pseudomonas
PubMed: 38871758
DOI: 10.1038/s41598-024-62973-5 -
Science (New York, N.Y.) Jun 2024Bacteria can repurpose their own bacteriophage viruses (phage) to kill competing bacteria. Phage-derived elements are frequently strain specific in their killing...
Bacteria can repurpose their own bacteriophage viruses (phage) to kill competing bacteria. Phage-derived elements are frequently strain specific in their killing activity, although there is limited evidence that this specificity drives bacterial population dynamics. Here, we identified intact phage and their derived elements in a metapopulation of wild plant-associated genomes. We discovered that the most abundant viral cluster encodes a phage remnant resembling a phage tail called a tailocin, which bacteria have co-opted to kill bacterial competitors. Each pathogenic strain carries one of a few distinct tailocin variants that target the variable polysaccharides in the outer membrane of co-occurring pathogenic strains. Analysis of herbarium samples from the past 170 years revealed that the same tailocin and bacterial receptor variants have persisted in populations. These results suggest that tailocin genetic diversity can be mined to develop targeted "tailocin cocktails" for microbial control.
Topics: Antibiosis; Bacterial Outer Membrane; Bacteriocins; Genetic Variation; Genome, Bacterial; Polysaccharides, Bacterial; Pseudomonas; Pseudomonas Phages; Viral Tail Proteins; Phage Therapy
PubMed: 38870284
DOI: 10.1126/science.ado0713 -
Methods in Molecular Biology (Clifton,... 2024One of the major plant stress level indicators is reactive oxygen species (ROS). They have been known to play a central role in regulating plant responses to various...
One of the major plant stress level indicators is reactive oxygen species (ROS). They have been known to play a central role in regulating plant responses to various environmental stresses. This book chapter specifically covers abiotic stress induced by a drought hormone abscisic acid and biotic stress induced by Pseudomonas syringe DC3000 on single cell-type guard cells. We describe in detail the measurement of ROS production starting from sample preparation to data analysis by fluorescence intensity acquisition using ImageJ software. We discussed the problems faced while performing the experiment and addressed how to overcome them by providing specific guidelines to ensure high quality repeatable data.
Topics: Reactive Oxygen Species; Arabidopsis; Stress, Physiological; Abscisic Acid; Pseudomonas syringae
PubMed: 38869797
DOI: 10.1007/978-1-0716-3973-3_14 -
World Journal of Microbiology &... Jun 2024It was known that UVc irradiation increases the reactive oxygen species' (ROS) levels in bacteria hence the intervention of antioxidant enzymes and causes also changes...
It was known that UVc irradiation increases the reactive oxygen species' (ROS) levels in bacteria hence the intervention of antioxidant enzymes and causes also changes in fatty acids (FAs) composition enabling bacteria to face antibiotics. Here, we intended to elucidate an interrelationship between SOD and susceptibility to antibiotics by studying FA membrane composition of UVc-treated P. aeruginosa PAO1 and its isogenic mutants (sodM, sodB and sod MB) membrane, after treatment with antibiotics. Swarmer mutants defective in genes encoding superoxide dismutase were pre-exposed to UVc radiations and then tested by disk diffusion method for their contribution to antibiotic tolerance in comparison with the P. aeruginosa wild type (WT). Moreover, fatty acid composition of untreated and UVc-treated WT and sod mutants was examined by Gaz chromatography and correlated to antibiotic resistance. Firstly, it has been demonstrated that after UVc exposure, swarmer WT strain, sodM and sodB mutants remain resistant to polymixin B, a membrane target antibiotic, through membrane unsaturation supported by the intervention of Mn-SOD after short UVc exposure and cyclopropanation of unsaturated FAs supported by the action of Fe-SOD after longer UVc exposure. However, resistance for ciprofloxacin is correlated with increase in saturated FAs. This correlation has been confirmed by a molecular docking approach showing that biotin carboxylase, involved in the initial stage of FA biosynthesis, exhibits a high affinity for ciprofloxacin. This investigation has explored the correlation of antibiotic resistance with FA content of swarmer P.aeruginosa pre-exposed to UVc radiations, confirmed to be antibiotic target dependant.
Topics: Anti-Bacterial Agents; Pseudomonas aeruginosa; Ultraviolet Rays; Superoxide Dismutase; Mutation; Cyclopropanes; Drug Resistance, Bacterial; Fatty Acids; Ciprofloxacin; Microbial Sensitivity Tests; Bacterial Proteins; Cell Membrane; Computer Simulation; Polymyxin B
PubMed: 38869625
DOI: 10.1007/s11274-024-04033-8 -
Frontiers in Immunology 2024Zinc finger Asp-His-His-Cys motif-containing (zDHHC) proteins, known for their palmitoyltransferase (PAT) activity, play crucial roles in diverse cellular processes,...
Zinc finger Asp-His-His-Cys motif-containing (zDHHC) proteins, known for their palmitoyltransferase (PAT) activity, play crucial roles in diverse cellular processes, including immune regulation. However, their non-palmitoyltransferase immunomodulatory functions and involvement in teleost immune responses remain underexplored. In this study, we systematically characterized the zDHHC family in the large yellow croaker (), identifying 22 members. Phylogenetic analysis unveiled that each of the 22 zDHHCs formed distinct clusters with their orthologues from other teleost species. Furthermore, all zDHHCs exhibited a highly conserved DHHC domain, as confirmed by tertiary structure prediction. Notably, zDHHC23 exhibited the most pronounced upregulation following () infection of macrophage/monocyte cells (MO/MΦ). Silencing zDHHC23 led to heightened pro-inflammatory cytokine expression and diminished anti-inflammatory cytokine levels in MO/MΦ during infection, indicating its anti-inflammatory role. Functionally, zDHHC23 facilitated M2-type macrophage polarization, as evidenced by a significant skewing of MO/MΦ towards the pro-inflammatory M1 phenotype upon zDHHC23 knockdown, along with the inhibition of MO/MΦ necroptosis induced by infection. These findings highlight the non-PAT immunomodulatory function of zDHHC23 in teleost immune regulation, broadening our understanding of zDHHC proteins in host-pathogen interactions, suggesting zDHHC23 as a potential therapeutic target for immune modulation in aquatic species.
Topics: Animals; Perciformes; Macrophages; Fish Proteins; Necroptosis; Phylogeny; Macrophage Activation; Fish Diseases; Acyltransferases; Pseudomonas; Cytokines
PubMed: 38868779
DOI: 10.3389/fimmu.2024.1401626 -
Microbial Cell Factories Jun 2024The objectives of the current study were to extract pyocyanin from Pseudomonas aeruginosa clinical isolates, characterize its chemical nature, and assess its biological...
Transforming microbial pigment into therapeutic revelation: extraction and characterization of pyocyanin from Pseudomonas aeruginosa and its therapeutic potential as an antibacterial and anticancer agent.
BACKGROUND
The objectives of the current study were to extract pyocyanin from Pseudomonas aeruginosa clinical isolates, characterize its chemical nature, and assess its biological activity against different bacteria and cancer cells. Due to its diverse bioactive properties, pyocyanin, being one of the virulence factors of P. aeruginosa, holds a promising, safe, and available therapeutic potential.
METHODS
30 clinical P. aeruginosa isolates were collected from different sources of infections and identified by routine methods, the VITEK 2 compact system, and 16 S rRNA. The phenazine-modifying genes (phzM, phzS) were identified using polymerase chain reaction (PCR). Pyocyanin chemical characterization included UV-Vis spectrophotometry, Fourier Transform Infra-Red spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and Liquid Chromatography-Mass Spectrometry (LC-MS). The biological activity of pyocyanin was explored by determining the MIC values against different clinical bacterial strains and assessing its anticancer activity against A549, MDA-MB-231, and Caco-2 cancer cell lines using cytotoxicity, wound healing and colony forming assays.
RESULTS
All identified isolates harboured at least one of the phzM or phzS genes. The co-presence of both genes was demonstrated in 13 isolates. The UV-VIS absorbance peaks were maxima at 215, 265, 385, and 520 nm. FTIR could identify the characteristic pyocyanin functional groups, whereas both GC-MS and LC-MS elucidated the chemical formula CHNO, with a molecular weight 210. The quadri-technical analytical approaches confirmed the chemical nature of the extracted pyocyanin. The extract showed broad-spectrum antibacterial activity, with the greatest activity against Bacillus, Staphylococcus, and Streptococcus species (MICs 31.25-125 µg/mL), followed by E. coli isolates (MICs 250-1000 µg/mL). Regarding the anticancer activity, the pyocyanin extract showed IC values against A549, MDA-MB-231, and Caco-2 cancer cell lines of 130, 105, and 187.9 µg/mL, respectively. Furthermore, pyocyanin has markedly suppressed colony formation and migratory abilities in these cells.
CONCLUSIONS
The extracted pyocyanin has demonstrated to be a potentially effective candidate against various bacterial infections and cancers. Hence, the current findings could contribute to producing this natural compound easily through an affordable method. Nonetheless, future studies are required to investigate pyocyanin's effects in vivo and analyse the results of combining it with other traditional antibiotics or anticancer drugs.
Topics: Pyocyanine; Pseudomonas aeruginosa; Anti-Bacterial Agents; Humans; Antineoplastic Agents; Microbial Sensitivity Tests; Cell Line, Tumor; Caco-2 Cells
PubMed: 38867319
DOI: 10.1186/s12934-024-02438-6 -
Scientific Reports Jun 2024Rhizoctonia solani, the causal agent of banded leaf and sheath blight (BL&SB), poses a significant threat to maize and various crops globally. The increasing concerns...
Rhizoctonia solani, the causal agent of banded leaf and sheath blight (BL&SB), poses a significant threat to maize and various crops globally. The increasing concerns surrounding the environmental and health impacts of chemical fungicides have encouraged intensified concern in the development of biological control agents (BCAs) as eco-friendly alternatives. In this study, we explored the potential of 22 rhizobacteria strains (AS1-AS22) isolates, recovered from the grasslands of the Pithoragarh region in the Central Himalayas, as effective BCAs against BL&SB disease. Among these strains, two Pseudomonas isolates, AS19 and AS21, exhibited pronounced inhibition of fungal mycelium growth in vitro, with respective inhibition rates of 57.04% and 54.15% in cell cultures and 66.56% and 65.60% in cell-free culture filtrates. Additionally, both strains demonstrated effective suppression of sclerotium growth. The strains AS19 and AS21 were identified as Pseudomonas sp. by 16S rDNA phylogeny and deposited under accession numbers NAIMCC-B-02303 and NAIMCC-B-02304, respectively. Further investigations revealed the mechanisms of action of AS19 and AS21, demonstrating their ability to induce systemic resistance (ISR) and exhibit broad-spectrum antifungal activity against Alternaria triticina, Bipolaris sorokiniana, Rhizoctonia maydis, and Fusarium oxysporum f. sp. lentis. Pot trials demonstrated significant reductions in BL&SB disease incidence (DI) following foliar applications of AS19 and AS21, with reductions ranging from 25 to 38.33% compared to control treatments. Scanning electron microscopy revealed substantial degradation of fungal mycelium by the strains, accompanied by the production of hydrolytic enzymes. These findings suggest the potential of Pseudomonas strains AS19 and AS21 as promising BCAs against BL&SB and other fungal pathogens. However, further field trials are warranted to validate their efficacy under natural conditions and elucidate the specific bacterial metabolites responsible for inducing systemic resistance. This study contributes to the advancement of sustainable disease management strategies and emphasizes the potential of Pseudomonas strains AS19 and AS21 in combating BL&SB and other fungal diseases affecting agricultural crops.
Topics: Plant Diseases; Zea mays; Pseudomonas; Rhizoctonia; Plant Leaves; Biological Control Agents; Pest Control, Biological; Antibiosis; Phylogeny
PubMed: 38866928
DOI: 10.1038/s41598-024-64028-1 -
PloS One 2024Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia...
OBJECTIVE
Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia marcescens, Pseudomonas aeruginosa and Stenotrophomonas maltophilia.
DESIGN
Over two years, three sampling campaigns were conducted in a neonatal intensive care unit (NICU). Samples from 19 sink drains were taken at three time points: before, during, and after disinfection. Bacterial concentration was measured using culture-based and flow cytometry methods. High-throughput short sequence typing was performed to identify the three OPs and assess S. marcescens persistence after disinfection at the genotypic level.
SETTING
This study was conducted in a pediatric hospitals NICU in Montréal, Canada, which is divided in an intensive and intermediate care side, with individual rooms equipped with a sink.
INTERVENTIONS
Five treatments were compared: self-disinfecting drains, chlorine disinfection, boiling water disinfection, hot tap water flushing, and steam disinfection.
RESULTS
This study highlights significant differences in the effectiveness of disinfection methods. Chlorine treatment proved ineffective in reducing bacterial concentration, including the three OPs. In contrast, all other drain interventions resulted in an immediate reduction in culturable bacteria (4-8 log) and intact cells (2-3 log). Thermal methods, particularly boiling water and steam treatments, exhibited superior effectiveness in reducing bacterial loads, including OPs. However, in drains with well-established bacterial biofilms, clonal strains of S. marcescens recolonized the drains after heat treatments.
CONCLUSIONS
Our study supports thermal disinfection (>80°C) for pathogen reduction in drains but highlights the need for additional trials and the implementation of specific measures to limit biofilm formation.
Topics: Serratia marcescens; Intensive Care Units, Neonatal; Disinfection; Humans; Pseudomonas aeruginosa; Infant, Newborn; Stenotrophomonas maltophilia; Serratia Infections; Cross Infection
PubMed: 38865328
DOI: 10.1371/journal.pone.0304378