At present, there is an urgent need in medicine and industry to develop new approaches to eliminate bacterial biofilms. Considering the low efficiency of classical approaches to biofilm eradication and the growing problem of antibiotic resistance, the introduction of nanomaterials may be a promising solution. Outstanding antimicrobial properties have been demonstrated by nanoparticles (NPs) of metal oxides and their nanocomposites. The review presents a comparative analysis of antibiofilm properties of various metal oxide NPs (primarily, CuO, Fe3O4, TiO2, ZnO, MgO, and Al2O3 NPs) and nanocomposites, as well as mechanisms of their effect on plankton bacteria cells and biofilms. The potential mutagenicity of metal oxide NPs and safety problems of their wide application are also discussed.

In this study, we have shown that substitution of chloride ligand for imidazole (Im) ring in the cyclometalated platinum complex Pt(phpy)(PPh)Cl (1; phpy, 2-phenylpyridine; PPh, triphenylphosphine), which is nonemissive in solution, switches on phosphorescence of the resulting compound. Crystallographic and nuclear magnetic resonance (NMR) spectroscopic studies of the substitution product showed that the luminescence ignition is a result of Im coordination to give the [Pt(phpy)(Im)(PPh)]Cl complex. The other imidazole-containing biomolecules, such as histidine and histidine-containing peptides and proteins, also trigger luminescence of the substitution products. The complex 1 proved to be highly selective toward the imidazole ring coordination that allows site-specific labeling of peptides and proteins with 1 using the route, which is orthogonal to the common bioconjugation schemes via lysine, aspartic and glutamic acids, or cysteine and does not require any preliminary modification of a biomolecule. The utility of this approach was demonstrated on (i) site-specific modification of the ubiquitin, a small protein that contains only one His residue in its sequence, and (ii) preparation of nonaggregated HSA-based Pt phosphorescent probe. The latter particles easily internalize into the live HeLa cells and display a high potential for live-cell phosphorescence lifetime imaging (PLIM) as well as for advanced correlation PLIM and FLIM experiments.

Amyloids are β-sheets-rich protein fibrils that cause neurodegenerative and other incurable human diseases affecting millions of people worldwide. However, a number of proteins is functional in the amyloid state in various organisms from bacteria to humans. Using an original proteomic approach, we identified a set of proteins forming amyloid-like aggregates in the brain of young healthy rats. One of them is the FXR1 protein, which is known to regulate memory and emotions. We showed that FXR1 clearly colocalizes in cortical neurons with amyloid-specific dyes Congo-Red, Thioflavines S and T. FXR1 extracted from brain by immunoprecipitation shows yellow-green birefringence after staining with Congo red. This protein forms in brain detergent-resistant amyloid oligomers and insoluble aggregates. RNA molecules that are colocalized with FXR1 in cortical neurons are insensitive to treatment with RNase A. All these data suggest that FXR1 functions in rat brain in amyloid form. The N-terminal amyloid-forming fragment of FXR1 is highly conserved across mammals. We assume that the FXR1 protein may be presented in amyloid form in brain of different species of mammals, including humans.

No abstract

Advanced wound dressings improve wound healing by releasing antibacterial agents, accelerating wound closure, and reporting (sensing) changes in the wound’s state. The challenge with the release of antibacterial agents such as drugs, peptides, or nanoparticles is their unregulated administration. In addition, bacteria resistance to antibiotics stimulates the search for new types of antibacterial wound dressings. Here, we report a new approach to antibacterial wound dressings by utilizing a nanocolloidal hydrogel with strong Fe3+ ion sequestration capability, thus depriving bacteria of much-needed ionic iron and suppressing bacteria growth. The hydrogel was derived from cellulose nanocrystals decorated with carbon dots (C-dot/CNCs). Upon Fe3+ ion uptake by the nanofibrillar hydrogel, the photoluminescence of the hydrogel was quenched, due to adsorption of ions to the C-dot surface, thus reporting on the removal of ionic iron from the medium. The hydrogel suppressed the growth of antibiotic-resistant Gram-negative Escherichia coli, antibiotic-resistant Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus and was noncytotoxic for human fibroblasts. Wound dressings were readily fabricated using three-dimensional (3D) printing. The new mechanism of antibacterial performance of the hydrogel, its sensing capability, biocompatibility, and the capability to 3D print wound dressing patches make it a very promising material for the fabrication of advanced wound dressings.

Hollow metallic capsules are of great interest given the large specific surface area and optical, electrical, and catalytic properties. To expand the possibilities of application and research of inorganic nano-and microparticles, new methodologies are being developed for obtaining metallic or multimetallic particles. For the first time, we propose a galvanic replacement reaction (GRR) with liquid gallium hydrocolloid to obtain a library of biand trimetallic functional capsules. The properties of the capsules are determined by the synthesis conditions, salt precursor, and stabilizer, providing control over the surface morphology and metal distribution. Furthermore, the resulting metallic capsules were tested for various functional properties, e.g., antimicrobial activity, and tailored for drug delivery systems. A wide variety of functional materials can be generated due to the ability to synthesize multimetallic capsules and incorporating a broad range of dopants.

Ribosomal RNA (rRNA) genes, whose activity results in nucleolus formation, constitute an extremely important part of genome. Despite the extensive exploration into avian genomes, no complete description of avian rRNA gene primary structure has been offered so far. We publish a complete chicken rRNA gene cluster sequence here, including 5’ETS (1836 bp), 18S rRNA gene (1823 bp), ITS1 (2530 bp), 5.8S rRNA gene (157 bp), ITS2 (733 bp), 28S rRNA gene (4441 bp) and 3’ETS (343 bp). The rRNA gene cluster sequence of 11863 bp was assembled from raw reads and deposited to GenBank under KT445934 accession number. The assembly was validated through in situ fluorescent hybridization analysis on chicken metaphase chromosomes using computed and synthesized specific probes, as well as through the reference assembly against de novo assembled rRNA gene cluster sequence using sequenced fragments of BAC-clone containing chicken NOR (nucleolus organizer region). The results have confirmed the chicken rRNA gene cluster validity.

The content of repetitive DNA in avian genomes is considerably less than in other investigated vertebrates. The first descriptions of tandem repeats were based on the results of routine biochemical and molecular biological experiments. Both satellite DNA and interspersed repetitive elements were annotated using library-based approach and de novo repeat identification in assembled genome. The development of deep-sequencing methods provides datasets of high quality without preassembly allowing one to annotate repetitive elements from unassembled part of genomes. In this work, we search the chicken assembly and annotate high copy number tandem repeats from unassembled short raw reads. Tandem repeat (GGAAA) has been identified and found to be the second after telomeric repeat (TTAGGG)n most abundant in the chicken genome. Furthermore, (GGAAA) repeat forms expanded arrays on the both arms of the chicken W chromosome. Our results highlight the complexity of repetitive sequences and update data about organization of sex W chromosome in chicken.