Biomaterial-centered infection is a much-dreaded complication associated with the use of biomedical implants. Although positively charged biomaterial surfaces stimulate bacterial adhesion, it has been suggested that surface growth of adhering Gram-negative bacilli is inhibited on positively charged surfaces. In the present paper, we determined the infection rate of differently charged poly(methacrylates) in rats. To this end, 2 x 10(6)/cm(2) Escherichia coli O2K2 or 2 x 10(4)/cm(2) Pseudomonas aeruginosa AK1 were seeded on glass discs coated with three differently charged poly(methacrylates) coatings in a parallel plate flow chamber. Three rats received six subcutaneous discs (two discs of each charge variant) seeded with E. coli, while three other rats received discs seeded with P. aeruginosa. The numbers of viable bacteria on the surfaces were determined 48h after implantation. On 50% of all positively charged discs viable E. coli were absent, while the negatively charged discs were all colonized by E. coli. P. aeruginosa, however, were isolated from both positively and negatively charged discs. Probably, P. aeruginosa can circumvent the antimicrobial effect of the positive charge through the formation of extracellular polysaccharides.
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http://dx.doi.org/10.1016/s0142-9612(03)00083-8 | DOI Listing |
Environ Sci Process Impacts
January 2025
Eberhard Karls University of Tübingen, Department of Geosciences, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.
Concentrations of pollutants like pharmaceuticals in soils typically decrease over time, though it often remains unclear whether this dissipation is caused by the transformation of the pollutant or a decreasing extractability. We developed a mathematical model that (1) explores the plausibility of different dissipation pathways, and (2) allows the quantification of concentration differences between aqueous soil extracts and soil solution. The model considers soil particles as uniform spheres, kinetic sorption towards an equilibrium (Freundlich model), and two dissipation pathways, irreversible transformation and mineralization (following 1 order kinetics) as well as the formation of non-extractable residues intraparticle diffusion.
View Article and Find Full Text PDFChemistry
January 2025
Politecnico di Milano, Department of Chemistry, Materials, Chemical Engineer., via Mancinelli 7, 20131, Milan, ITALY.
Molecular recognition mediated by s-hole interactions is enhanced as the electrostatic potential at the σ-hole becomes increasingly positive. Traditional methods to strengthen σ-hole donor ability of atoms such as halogens often involve covalent modifications, such as, introducing electron-withdrawing substituents (neutral or positively charged) or electrochemical oxidation. Metal coordination, a relatively underexplored approach, offers a promising alternative.
View Article and Find Full Text PDFJ Virol
January 2025
Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
Birnaviruses infect a broad range of vertebrate hosts, including fish and birds, and cause substantial economic losses in the fishery and livestock industries. The infectious pancreatic necrosis virus (IPNV), an aquabirnavirus, specifically infects salmonids. While structures on T=1 subviral particles of the birnaviruses, including IPNV, have been studied, structural insights into the infectious T=13 particles have been limited to the infectious bursal disease virus (IBDV), an avibirnavirus.
View Article and Find Full Text PDFElife
January 2025
State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
Viral adhesion to host cells is a critical step in infection for many viruses, including monkeypox virus (MPXV). In MPXV, the H3 protein mediates viral adhesion through its interaction with heparan sulfate (HS), yet the structural details of this interaction have remained elusive. Using AI-based structural prediction tools and molecular dynamics (MD) simulations, we identified a novel, positively charged α-helical domain in H3 that is essential for HS binding.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Max-Planck-Institut für Immunbiologie und Epigenetik (MPI-IE), Stübeweg 51, 79108 Freiburg im Breisgau, Germany.
Intrinsically disordered regions are found in most eukaryotic proteins and are enriched with positively and negatively charged residues. While it is often convenient to assume that these residues follow their model-compound p values, recent work has shown that local charge effects (charge regulation) can upshift or downshift side chain p values with major consequences for molecular function. Despite this, charge regulation is rarely considered when investigating disordered regions.
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