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International Journal of Molecular... May 2024The pyoverdine siderophore is produced by to access iron. Its synthesis involves the complex coordination of four nonribosomal peptide synthetases (NRPSs), which are...
The pyoverdine siderophore is produced by to access iron. Its synthesis involves the complex coordination of four nonribosomal peptide synthetases (NRPSs), which are responsible for assembling the pyoverdine peptide backbone. The precise cellular organization of these NRPSs and their mechanisms of interaction remain unclear. Here, we used a combination of several single-molecule microscopy techniques to elucidate the spatial arrangement of NRPSs within pyoverdine-producing cells. Our findings reveal that PvdL differs from the three other NRPSs in terms of localization and mobility patterns. PvdL is predominantly located in the inner membrane, while the others also explore the cytoplasmic compartment. Leveraging the power of multicolor single-molecule localization, we further reveal co-localization between PvdL and the other NRPSs, suggesting a pivotal role for PvdL in orchestrating the intricate biosynthetic pathway. Our observations strongly indicates that PvdL serves as a central orchestrator in the assembly of NRPSs involved in pyoverdine biosynthesis, assuming a critical regulatory function.
Topics: Pseudomonas aeruginosa; Oligopeptides; Peptide Synthases; Bacterial Proteins; Siderophores
PubMed: 38892200
DOI: 10.3390/ijms25116013 -
International Journal of Molecular... May 2024The aim of this work was to develop and characterize a thin films composed of hyaluronic acid/ellagic acid for potential medical application. Its principal novelty,...
The aim of this work was to develop and characterize a thin films composed of hyaluronic acid/ellagic acid for potential medical application. Its principal novelty, distinct from the prior literature in terms of hyaluronic acid films supplemented with phenolic acids, resides in the predominant incorporation of ellagic acid-a distinguished compound-as the primary constituent of the films. Herein, ellagic acid was dissolved in two different solvents, i.e., acetic acid (AcOH) or sodium hydroxide (NaOH), and the surface properties of the resultant films were assessed using atomic force microscopy and contact angle measurements. Additionally, various physicochemical parameters were evaluated including moisture content, antioxidant activity, and release of ellagic acid in phosphate buffered saline. Furthermore, the evaluation of films' biocompatibility was conducted using human epidermal keratinocytes, dermal fibroblasts, and human amelanotic melanoma cells (A375 and G361), and the antimicrobial activity was elucidated accordingly against ATCC 6538 and ATCC 15442. Our results showed that the films exhibited prominent antibacterial properties particularly against , with the 80HA/20EA/AcOH film indicating the strong biocidal activity against this strain leading to a significant reduction in viable cells. Comparatively, the 50HA/50EA/AcOH film also displayed biocidal activity against . This experimental approach could be a promising technique for future applications in regenerative dermatology or novel strategies in terms of bioengineering.
Topics: Hyaluronic Acid; Humans; Staphylococcus aureus; Biocompatible Materials; Ellagic Acid; Pseudomonas aeruginosa; Anti-Bacterial Agents; Antioxidants; Fibroblasts; Keratinocytes; Microbial Sensitivity Tests; Cell Line, Tumor; Surface Properties
PubMed: 38892078
DOI: 10.3390/ijms25115891 -
International Journal of Molecular... May 2024Peptides displaying antimicrobial properties are being regarded as useful tools to evade and combat antimicrobial resistance, a major public health challenge. Here we...
Peptides displaying antimicrobial properties are being regarded as useful tools to evade and combat antimicrobial resistance, a major public health challenge. Here we have addressed dendrimers, attractive molecules in pharmaceutical innovation and development displaying broad biological activity. Triazine-based dendrimers were fully synthesized in the solid phase, and their antimicrobial activity and some insights into their mechanisms of action were explored. Triazine is present in a large number of compounds with highly diverse biological targets with broad biological activities and could be an excellent branching unit to accommodate peptides. Our results show that the novel peptide dendrimers synthesized have remarkable antimicrobial activity against Gram-negative bacteria ( and ) and suggest that they may be useful in neutralizing the effect of efflux machinery on resistance.
Topics: Dendrimers; Triazines; Microbial Sensitivity Tests; Escherichia coli; Pseudomonas aeruginosa; Antimicrobial Peptides; Anti-Bacterial Agents; Anti-Infective Agents; Antimicrobial Cationic Peptides
PubMed: 38892071
DOI: 10.3390/ijms25115883 -
Cells Jun 2024Precise control of neuronal activity is crucial for the proper functioning of neurons. How lipid homeostasis contributes to neuronal activity and how much of it is...
Precise control of neuronal activity is crucial for the proper functioning of neurons. How lipid homeostasis contributes to neuronal activity and how much of it is regulated by cells autonomously is unclear. In this study, we discovered that absence of the lipid regulator , a functional ortholog of the peroxisome proliferator-activated receptor (PPAR) in , resulted in defective pathogen avoidance behavior against (PA14). Functional NHR-49 was required in the neurons, and more specifically, in a set of oxygen-sensing body cavity neurons, URX, AQR, and PQR. We found that lowering the neuronal activity of the body cavity neurons improved avoidance in mutants. Calcium imaging in URX neurons showed that mutants displayed longer-lasting calcium transients in response to an O upshift, suggesting that excess neuronal activity leads to avoidance defects. Cell-specific rescue of NHR-49 in the body cavity neurons was sufficient to improve pathogen avoidance, as well as URX neuron calcium kinetics. Supplementation with oleic acid also improved avoidance behavior and URX calcium kinetics, suggesting that the defective calcium response in the neuron is due to lipid dysfunction. These findings highlight the role of cell-autonomous lipid regulation in neuronal physiology and immune behavior.
Topics: Animals; Caenorhabditis elegans; Lipid Metabolism; Caenorhabditis elegans Proteins; Neurons; Pseudomonas aeruginosa; Calcium; Mutation; Avoidance Learning; Receptors, Cytoplasmic and Nuclear
PubMed: 38891110
DOI: 10.3390/cells13110978 -
Applied Microbiology and Biotechnology Jun 2024Non-symbiotic N-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has...
Non-symbiotic N-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has successfully enhanced NH release. In this study, we compared the competitive fitness of A. vinelandii mutant strains, which allowed us to analyze the burden of NH release under a broad dynamic range. Long-term competition assays under regular culture conditions confirmed a large burden for NH release, exclusion by the wt strain, phenotypic instability, and loss of the ability to release NH. In contrast, co-inoculation in mild autoclaved soil showed a much longer co-existence with the wt strain and a stable NH release phenotype. All genetically modified strains increased the N content and changed its chemical speciation in the soil. This study contributes one step forward towards bridging a knowledge gap between molecular biology laboratory research and the incorporation of N from the air into the soil in a molecular species suitable for plant nutrition, a crucial requirement for developing improved bacterial inoculants for economic and environmentally sustainable agriculture. KEY POINTS: • Genetic engineering for NH excretion imposes a fitness burden on the culture medium • Large phenotypic instability for NH-excreting bacteria in culture medium • Lower fitness burden and phenotypic instability for NH-excreting bacteria in soil.
Topics: Soil Microbiology; Azotobacter vinelandii; Ammonium Compounds; Nitrogen Fixation; Nitrogen; Genetic Fitness; Phenotype; Soil; Culture Media; Genetic Engineering
PubMed: 38888816
DOI: 10.1007/s00253-024-13231-1 -
Antimicrobial Resistance and Infection... Jun 2024Stenotrophomonas maltophilia, a multidrug-resistant gram-negative bacteria (GNB), is an emerging nosocomial pathogen. This study assessed the clinical outcomes of GNB...
Gram-negative bacterial infections in surgical intensive care unit patients following abdominal surgery: high mortality associated with Stenotrophomonas maltophilia infection.
BACKGROUND
Stenotrophomonas maltophilia, a multidrug-resistant gram-negative bacteria (GNB), is an emerging nosocomial pathogen. This study assessed the clinical outcomes of GNB infections in surgical intensive care unit (SICU) patients post-abdominal surgery, focusing on the differences between S. maltophilia and other GNBs, including Pseudomonas aeruginosa.
METHODS
A retrospective study was conducted on SICU patients at Kaohsiung Chang Gung Memorial Hospital from 2010 to 2020, who developed GNB infections following abdominal surgery.
RESULTS
Of 442 patients, 237 had S. maltophilia and 205 had non-S. maltophilia GNB infections (including 81 with P. aeruginosa). The overall mortality rate was 44.5%, and S. maltophilia infection emerged as a significant contributor to the mortality rate in patients with GNB infections. S. maltophilia patients had longer mechanical ventilation and SICU stays, with a 30-day mortality rate of 35.4%, higher than the non-S. maltophilia GNB (22.9%) and P. aeruginosa (21%) groups. In-hospital mortality was also higher in the S. maltophilia group (53.2%) compared to the non-S. maltophilia GNB (34.6%) and P. aeruginosa groups (29.6%). Risk factors for acquiring S. maltophilia included a higher Sequential Organ Failure Assessment score and prior broad-spectrum antibiotics use. Older age, polymicrobial infections, and elevated bilirubin were associated with increased 30-day mortality in S. maltophilia patients.
CONCLUSION
S. maltophilia infections in post-abdominal surgery patients are linked to higher mortality than non-S. maltophilia GNB and P. aeruginosa infections, emphasizing the need for early diagnosis and treatment to improve outcomes.
Topics: Humans; Stenotrophomonas maltophilia; Gram-Negative Bacterial Infections; Male; Retrospective Studies; Female; Middle Aged; Intensive Care Units; Aged; Abdomen; Hospital Mortality; Pseudomonas aeruginosa; Adult; Cross Infection; Anti-Bacterial Agents
PubMed: 38886759
DOI: 10.1186/s13756-024-01411-7 -
BMC Complementary Medicine and Therapies Jun 2024Biofilms and oxidative stress retard wound healing. The resistance of biofilms to antibiotics has led to a search for alternative approaches in biofilm elimination....
BACKGROUND
Biofilms and oxidative stress retard wound healing. The resistance of biofilms to antibiotics has led to a search for alternative approaches in biofilm elimination. Antioxidants work synergistically with antibacterial agents against biofilms. Hence recent research has suggested plants as candidates in the development of new alternatives in biofilm treatments and as antioxidants due to the presence of phytocompounds which are responsible for their bioactivities. Hoslundia opposita Vahl is one of the plants used by traditional healers to treat wounds and other infections, this makes it a potential candidate for drug discovery hence, in this study, we investigate the antibiofilm and antioxidant activity of methanolic extract of hoslundia opposita Vahl from Uganda. We also identify phytochemicals responsible for its bioactivity.
METHOD
the plant was extracted by maceration using methanol, and the extract was investigated for antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. The antibiofilm activity using microtiter plate assay (MTP) assay where the Minimum biofilm inhibitory concentration required to inhibit 50% or 90% of the biofilm (MBIC and MBIC) and Minimum biofilm eradication concentration required to remove 50% or 90% of the biofilm (MBEC and MBEC) were measured. It was further analysed for its phytochemical composition using quantitative screening, as well as Gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography mass-spectrometry (LC-MS).
RESULTS
H. Opposita Vahl extract showed good antioxidant activity with of 249.6 mg/mL. It inhibited the growth of P. aeruginosa and S. aureus biofilms with MBIC of 28.37 mg/mL and 10 mg/mL, respectively. It showed the ability to eradicate P. aeruginosa and S. aureus biofilms with MBEC of 23.85 and 39.01 mg/mL respectively. Phytochemical analysis revealed the presence of alkaloids, tannins, flavonoids, and phenols. GC-MS analysis revealed 122 compounds in the extract of which, 23 have evidence of antioxidant or antibiofilm activity in literature. The most abundant compounds were; 1,4- Citric acid, Tetracontane-1,40-diol (43.43.3%, 1, Olean-12-en-28-oic acid, 3-hydroxy-, methyl ester, (3.beta) (15.36%) 9-Octadecenamide (12.50%), Squalene (11.85%) Palmitic Acid 4TMS (11.28%), and alpha Amyrin (11.27%). The LC-MS identified 115 and 57 compounds in multiple reaction mode (MRM) and scan modes respectively.
CONCLUSION
H. opposita Vahl showed antibiofilm and antioxidant activity due to bioactive compounds identified, hence the study justifies its use for wound healing. It can be utilised in further development of new drugs as antibiofilm and antioxidants.
Topics: Biofilms; Antioxidants; Plant Extracts; Wound Healing; Anti-Bacterial Agents; Pseudomonas aeruginosa; Microbial Sensitivity Tests; Uganda; Staphylococcus aureus; Humans; Phytochemicals
PubMed: 38886717
DOI: 10.1186/s12906-024-04540-z -
BMC Microbiology Jun 2024Addressing microbial resistance urgently calls for alternative treatment options. This study investigates the impact of a bimetallic formulation containing colistin,...
BACKGROUND
Addressing microbial resistance urgently calls for alternative treatment options. This study investigates the impact of a bimetallic formulation containing colistin, silver, and copper oxide on a pandrug-resistant, highly virulent Pseudomonas aeruginosa (P. aeruginosa) isolate from a cancer patient at the National Cancer Institute, Cairo University, Egypt.
METHODS
Silver nanoparticles (Ag NPs), copper oxide nanoparticles (CuO NPs), and bimetallic silver-copper oxide nanoparticles (Ag-CuO NPs) were synthesized using gamma rays, combined with colistin (Col), and characterized by various analytical methods. The antimicrobial activity of Col-Ag NPs, Col-CuO NPs, and bimetallic Col-Ag-CuO NPs against P. aeruginosa was evaluated using the agar well diffusion method, and their minimum inhibitory concentration (MIC) was determined using broth microdilution. Virulence factors such as pyocyanin production, swarming motility, and biofilm formation were assessed before and after treatment with bimetallic Col-Ag-CuO NPs. The in vivo efficacy was evaluated using the Galleria mellonella model, and antibacterial mechanism were examined through membrane leakage assay.
RESULTS
The optimal synthesis of Ag NPs occurred at a gamma ray dose of 15.0 kGy, with the highest optical density (OD) of 2.4 at 375 nm. Similarly, CuO NPs had an optimal dose of 15.0 kGy, with an OD of 1.5 at 330 nm. Bimetallic Ag-CuO NPs were most potent at 15.0 kGy, yielding an OD of 1.9 at 425 nm. The MIC of colistin was significantly reduced when combined with nanoparticles: 8 µg/mL for colistin alone, 0.046 µg/mL for Col-Ag NPs, and 0.0117 µg/mL for Col-Ag-CuO NPs. Bimetallic Col-Ag-CuO NPs reduced the MIC four-fold compared to Col-Ag NPs. Increasing the sub-inhibitory concentration of bimetallic nanoparticles from 0.29 × 10 to 0.58 × 10 µg/mL reduced P. aeruginosa swarming by 32-64% and twitching motility by 34-97%. At these concentrations, pyocyanin production decreased by 39-58%, and biofilm formation was inhibited by 33-48%. The nanoparticles were non-toxic to Galleria mellonella, showing 100% survival by day 3, similar to the saline-treated group.
CONCLUSIONS
The synthesis of bimetallic Ag-CuO NPs conjugated with colistin presents a promising alternative treatment for combating the challenging P. aeruginosa pathogen in hospital settings. Further research is needed to explore and elucidate the mechanisms underlying the inhibitory effects of colistin-bimetallic Ag-CuO NPs on microbial persistence and dissemination.
Topics: Pseudomonas aeruginosa; Colistin; Copper; Anti-Bacterial Agents; Microbial Sensitivity Tests; Silver; Animals; Metal Nanoparticles; Biofilms; Pseudomonas Infections; Drug Resistance, Multiple, Bacterial; Humans; Moths; Virulence Factors; Egypt
PubMed: 38886632
DOI: 10.1186/s12866-024-03358-6 -
Journal of Hazardous Materials Aug 2024Effective treatment of industrial wastewater containing complex pollutants, such as nitrate (NO-N) and organic pollutants, remains a significant challenge to date. Here,...
Enhanced denitrification and p-nitrophenol removal performance via hydrophilic sponge carriers fixed with dual-bacterial: Optimization, performance, and enhancement mechanism.
Effective treatment of industrial wastewater containing complex pollutants, such as nitrate (NO-N) and organic pollutants, remains a significant challenge to date. Here, a strain Nocardioides sp. ZS2 with denitrification and degradation of p-nitrophenol (PNP) was isolated and its culture conditions were optimized by kinetic analysis. Hydrophilic sponge carriers were prepared using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and chitosan (CS) to construct bioreactors. Furthermore, to further enhance the PNP degradation and denitrification performance of bioreactors, Pseudomonas stutzeri GF2 with denitrification capability was introduced. The results revealed that the removal efficiencies of PNP and NO-N reached 97.9 % and 91.9 %, respectively, when hydraulic retention time (HRT) of 6 h, C/N of 2.0, and pH of 6.5. The bioreactor exhibited stable denitrification performance even with fluctuations in the influent PNP concentration. The potential functional prediction results revealed that the abundance of amino acids, fatty acids, and carbohydrates increased as the influent C/N decreased, reflecting a tendency of the microbial community to adjust carbon source utilization to maintain cell growth, metabolic balance, and resist adverse C/N environments. This research provides new insights into the effective removal of organic pollutants and NO-N in wastewater treatment.
Topics: Nitrophenols; Bioreactors; Denitrification; Water Pollutants, Chemical; Hydrophobic and Hydrophilic Interactions; Chitosan; Pseudomonas stutzeri; Polyvinyl Alcohol; Carboxymethylcellulose Sodium; Biodegradation, Environmental; Nitrates; Wastewater; Actinobacteria; Waste Disposal, Fluid
PubMed: 38885589
DOI: 10.1016/j.jhazmat.2024.134922 -
Microbial Biotechnology Jun 2024Pathogens resistant to classical control strategies pose a significant threat to crop yield, with seeds being a major transmission route. Bacteriophages, viruses...
Pathogens resistant to classical control strategies pose a significant threat to crop yield, with seeds being a major transmission route. Bacteriophages, viruses targeting bacteria, offer an environmentally sustainable biocontrol solution. In this study, we isolated and characterized two novel phages, Athelas and Alfirin, which infect Pseudomonas syringae and Agrobacterium fabrum, respectively, and included the recently published Pfeifenkraut phage infecting Xanthomonas translucens. Using a simple immersion method, phages coated onto seeds successfully lysed bacteria post air-drying. The seed coat mucilage (SCM), a polysaccharide-polymer matrix exuded by seeds, plays a critical role in phage binding. Seeds with removed mucilage formed five to 10 times less lysis zones compared to those with mucilage. The podovirus Athelas showed the highest mucilage dependency. Phages from the Autographiviridae family also depended on mucilage for seed adhesion. Comparative analysis of Arabidopsis SCM mutants suggested the diffusible cellulose as a key component for phage binding. Long-term activity tests demonstrated high phage stability on seed surfaces and significantly increasing seedling survival rates in the presence of pathogens. Using non-virulent host strains enhanced phage presence on seeds but also has potential limitations. These findings highlight phage-based interventions as promising, sustainable strategies for combating pathogen resistance and improving crop yield.
Topics: Seeds; Pseudomonas syringae; Plant Diseases; Bacteriophages; Arabidopsis; Xanthomonas; Plant Mucilage; Biological Control Agents; Virus Attachment
PubMed: 38884488
DOI: 10.1111/1751-7915.14507