The paper presents the results of study on four Parmotrema species in Poland, P. arnoldii, P. crinitum, P. perlatum and P. stuppeum. They are mainly known from southern part of the country, mostly in ...the Carpathians. P. perlatum is reported also from Northern Poland and Central Poland. For P. stuppeum, so far known from single locality only, three new sites are reported. All the species seem to be rare and endangered in Poland. This work is the first part of a larger series which will present data on selected genera of the lichen family Parmeliaceae in Poland.
Pseudomonas aeruginosa biofilm-associated infections are a serious medical problem, and new compounds and therapies acting through novel mechanisms are much needed. Herein, the authors report a ...ruthenium(IV) complex that reduces P. aeruginosa PAO1 biofilm formation by 84%, and alters biofilm morphology and the living-to-dead cell ratio at 1 mM concentration. Including the compound in the culture medium altered the pigments secreted by PAO1, and fluorescence spectra revealed a decrease in pyoverdine. Scanning electron microscopy showed that the ruthenium complex did not penetrate the bacterial cell wall, but accumulated on external cell structures. Fluorescence quenching experiments indicated strong binding of the ruthenium complex to both plasmid DNA and bovine serum albumin. Formamidopyrimidine DNA N-glycosylase (Fpg) protein digestion of plasmid DNA isolated after ruthenium(IV) complex treatment revealed the generation of oxidative stress, which was further proved by the observed upregulation of catalase and superoxide dismutase gene expression.
The reaction of zinc salts with heterocyclic ether (1-ethoxymethyl-2-methylimidazole (1-ExMe-2-MeIm)), acid (pyridine-2,3-dicarboxylic acid (2,3-pydcH2)) and amide (3,5-dimethylpyrazole-1-carboxamide ...(3,5-DMePzCONH2)) yielded three new zinc complexes formulated as Zn(1-ExMe-2-MeIm)2Cl2 1, fac-Zn(H2O)6Zn(2,3-pydcH)322 and Zn(3,5-DMePz)2(NCO)2 3. Complexes of 1 and 3 are four-coordinated with a tetrahedron as coordination polyhedron. However, compound 2 forms an octahedral cation–anion complex. The complex 3 was prepared by eliminating of the carboxamide group from the ligand and then the 3,5-dimethylpyrazole (3,5-DMePz) and isocyanates formed were employed as new ligands. The IR and X-ray studies have confirmed a bidentate fashion of coordination of the 2,3-pydcH and monodentate fashion of coordination of the 1-ExMe-2-MeIm and 3,5-DMePz to the Zn(II) ions. The crystal packing of Zn(II) complexes are stabilized by intermolecular classical hydrogen bonds of O–H⋯O and N–H⋯O types. The most interesting feature of the supramolecular architecture of complexes is the existence of C–H⋯O, C–H⋯Cl and C–H⋯π interactions and π⋯π stacking, which also contributes to structural stabilisation. The correlation between crystal structure and thermal stability of zinc complexes is observed. In all compounds the fragments of ligands donor-atom containing go in the last steps. Additionally, antimicrobial activities of compounds were carried out against certain Gram-positive and Gram-negative bacteria and counts of CFU (colony forming units) were also determined. The achieved results confirmed a significant antibacterial activity of some tested zinc complexes. On the basis of the Δ log CFU values the antibacterial activity of zinc complexes follows the order: 3 > 2 > 1. Influence a number of N-donor atoms in zinc environment on antibacterial activity is also observed.
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•Synthesis of three new Zn(II) complexes with heterocyclic ether, acid and amide.•The compounds were characterised by elemental analysis, X-ray, IR and thermal studies.•The complexes of 1 and 3 are four-coordinated however, compound 2 forms an octahedral cation–anion complex.•The ligands and the Zn(II) complexes have been tested against Gram(+) and Gram(−) bacteria.•The achieved results confirmed a significant antibacterial activity of some tested zinc complexes.
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•Synthesis of three new Mn(II) complexes with N,O-donor heteroaromatic alcohol and aldehyde.•Compounds were characterised by X-ray, IR, Raman, EPR with DFT, magnetic and thermal ...studies.•Mn(II) ion is eight-coordinated in 1 and 2, whereas in 3 the coordination number of Mn(II) is six.•The ligands and the Mn(II) complexes have been tested in vitro against Gram(+) and Gram(−) bacteria.•Antibacterial activity of the Mn(II) complexes is selective for Gram(+) or Gram(−) bacteria.
Crystal, molecular and electronic structure of new manganese(II) compounds: Mn(2-CH2OHpy)2(NO3)2 (1), Mn(4-CHO-5-MeIm)2(NO3)2 (2) and Mn(4-CHO-5-MeIm)2Cl2 (3), where 2-hydroxymethylpyridine (2-CH2OHpy) and 5(4)-carbaldehyde-4(5)-methylimidazole (5(4)-CHO-4(5)-MeIm), have been characterised using X-ray, spectroscopic, magnetic and TG/DTG data. In compounds 1 and 2, the Mn(II) ion is eight-coordinated forming distorted pseudo-dodecahedron, that is rather unusual for the manganese(II) complexes, whereas in 3 the Mn(II) ion environment is a distorted octahedron. The high coordination number (CN=8) of 1 and 2 results from bidentate character of the nitrate ligands. The X-band EPR spectra of compounds 2 and 3 exhibit fine structure signals resulting from zero-field splitting (ZFS) of the spin states for high spin d5 Mn(II), whereas for 1 the broad isotropic signals were observed. The estimation of ZFS for individual Mn(II) ions was carried out for all compounds using DFT calculations. The free ligands and their manganese(II) complexes have been tested in vitro against gram-positive and gram-negative bacteria in order to assess their antimicrobial properties.
A novel single site Mn(II) complex was successfully synthesized and tested in the aqueous disproportionation of hydrogen peroxide. The complex was found to be stable (HR-XAS) and exhibits ...catalase-like activity in neutral pH. Theoretical calculations suggested a reaction mechanism involving two complexes, changes in metal oxidation state and proton shuttling.
Coordination polyhedra of calcium(II) complexes with 2-hydroxymethylpyridine (1), 4-methyl-5-carbaldehydeimidazole (2) and picolinate (3). Display omitted
► New calcium(II) complexes with chelating ...N, O-ligands were synthesized. ► Obtained complexes are small models for calcium coordination in biological systems. ► The comparison of X-ray data of Ca(II) and Cd(II) complexes was done. ► From chemical point of view X-ray data confirmed that toxic Cd(II) may replace Ca(II) in biological systems too. ► Cd(II) analogues tested for cytotoxicity revealed similar activity.
Three new calcium(II) complexes with heterocyclic alcohol (2-hydroxymethylpyridine), aldehyde (4-methyl-5-carbaldehydeimidazole) and carboxylate (picolinate, obtained in situ) moieties were synthesised and characterised using elemental analysis, X-ray, IR (Raman), 1H, and 13C NMR methods. In addition, we compared the X-ray results obtained for calcium(II) complexes with the structures of previously described cadmium compounds, which from the chemical point of view (HSAB and Lewis acids and bases theories) can give some information for the ability of Cd2+ to mimic Ca2+ ions in biological systems too. The studied ligands, calcium compounds (1–3) and cadmium analogues were tested for their cytotoxicity against HeLa (cervical carcinoma), K562 (leukaemia) and normal cells (HUVEC) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.
Proteus mirabilis is a pathogenic gram-negative bacterium that frequently causes kidney infections, typically established by ascending colonization of the urinary tract. The present study is focused ...on ureolytic activity and urease inhibition in biofilms generated by P. mirabilis O18 cells. Confocal microscopy revealed morphological alterations in biofilms treated with urea and a urease inhibitor (acetohydroxamic acid, AHA), as some swarmer cells were found to protrude from the biofilm. The presence of a quorum-sensing molecule (N-butanoyl homoserine lactone, BHL) increased biofilm thickness and its ureolytic activity. Laser interferometric determination of diffusion showed that urea easily diffuses through P. mirabilis biofilm, while AHA is blocked. This may suggest that the use of urease inhibitors in CAUTIs may by less effective than in other urease-associated infections. Spectroscopic studies revealed differences between biofilm and planktonic cells indicating that polysaccharides and nucleic acids are involved in extracellular matrix and biofilm formation.
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