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Bimetallic nanoparticles (BMNPs) combine unique and synergistic properties of two metals, allowing new specific applications. In this study, bimetallic AuFe nanoparticles and their conjugates with methotrexate (MTX) were obtained with an environmentally safe method of metal-vapor synthesis. The composition and electronic structure of the particles were investigated with X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectrum and X-ray absorption spectroscopy (XANES and EXAFS). The effects of BMNP-MTX conjugates on human primary cells and tumor cell lines were evaluated with neutral red uptake and MTT in vitro cytotoxicity assays. Bright-field microscopy analyses of tumor spheroid size and evaluations of tumor spheroid vitality based on SFDA AM staining were carried out. In vitro assays for an antibacterial activity evaluation of the generated samples were performed. The influence of BMNP-MTX on cytokine production with normal leukocytes was assessed using ELISA. X-ray analyses of the samples demonstrated that gold was in the ground state Au0 as well as Au+ and Au3+ states are present in small quantities, whereas iron existed as a mixture of non-histometric oxides with states close to Fe2+ and Fe3+. The modification of the AuFe system with MTX is accompanied by a threefold increase in the relative proportion of the Au+ state. BMNP-MTX conjugates demonstrated significant antitumor activity compared to the drug alone, which proves the ability of the generated nanoconjugates to improve the effectiveness of MTX therapy. This was confirmed by a marked reduction in the size and vitality of AuFe-MTX-treated 3D tumor spheroids. In addition to their selective antitumor activity, AuFe-MTX exhibited moderate antibacterial activity and induced sample-specific cytokine production with normal human leukocytes—which points to an immunostimulatory potential. The present findings indicate important and diverse biological properties of BMNP-MTX conjugates and thus highlight perspectives for their biomedical applications and new immune-specific abilities. [ABSTRACT FROM AUTHOR]

Au and Fe nanoparticles and their conjugates with the drug methotrexate were obtained by an environmentally safe method of metal–vapor synthesis (MVS). The materials were characterized by transmission and scanning electron microscopy (TEM, SEM), X-ray photoelectron spectroscopy (XPS), and small-angle X-ray scattering using synchrotron radiation (SAXS). The use of acetone as an organic reagent in the MVS makes it possible to obtain Au and Fe particles with an average size of 8.3 and 1.8 nm, respectively, which was established by TEM. It was found that Au, both in the NPs and the composite with methotrexate, was in the Au0, Au+ and Au3+ states. The Au 4f spectra for Au-containing systems are very close. The effect of methotrexate was manifested in a slight decrease in the proportion of the Au0 state—from 0.81 to 0.76. In the Fe NPs, the main state is the Fe3+ state, and the Fe2+ state is also present in a small amount. The analysis of samples by SAXS registered highly heterogeneous populations of metal nanoparticles coexisting with a wide proportion of large aggregates, the number of which increased significantly in the presence of methotrexate. For Au conjugates with methotrexate, a very wide asymmetric fraction with sizes up to 60 nm and a maximum of ~4 nm has been registered. In the case of Fe, the main fraction consists of particles with a radius of 4.6 nm. The main fraction consists of aggregates up to 10 nm. The size of the aggregates varies in the range of 20–50 nm. In the presence of methotrexate, the number of aggregates increases. The cytotoxicity and anticancer activity of the obtained nanomaterials were determined by MTT and NR assays. Fe conjugates with methotrexate showed the highest toxicity against the lung adenocarcinoma cell line and Au nanoparticles loaded with methotrexate affected the human colon adenocarcinoma cell line. Both conjugates displayed lysosome-specific toxicity against the A549 cancer cell line after 120 h of culture. The obtained materials may be promising for the creation of improved agents for cancer treatment. [ABSTRACT FROM AUTHOR]

Cyanobacteria live in a wide range of habitats encompassing freshwater, marine, and terrestrial ecosystems. They are one of the most morphologically diverse groups. Techniques based on polyphasic taxonomy were introduced to cyanobacterial systematics in an attempt to overcome the shortcomings brought by the traditional emphasis on morphological features. Recent advances in genomics are greatly accelerating our understanding of cyanobacterial taxonomy. Genomes available in NCBI's GenBank were selected to comprehensively clarify the genetic similarities and differences of representatives of genus Phormidium and Phormidesmis priestleyi ULC007 (former Phormidium priestleyi). We performed a comparative genomic analysis, which includes analysis of genome characteristics and annotation of the subsystem, classification of functionally annotated common genes and automatic annotation of secondary metabolic gene clusters. Results showed that about 83% of the genes in the studied cyanobacterial genomes were identified as genes with unknown functions, and those with annotated functions were mainly involved in: (I) cofactors, vitamins, prosthetic groups, and pigments; (II) cell wall and capsule; (III) RNA metabolism; (IV) protein metabolism; (V) DNA metabolism, (VI) fatty acids, lipids, and isoprenoids; (VII) respiration; (VIII) stress response; (IX) amino acids and derivatives; and (X) carbohydrates We found that Phormidesmis priestleyi ULC007 possess seven genes involved in the chemotaxis. The in silico identification, annotation and analysis of the secondary metabolite biosynthesis gene clusters of the most promising targets within the studied cyanobacterial genomes showed presence of specific secondary metabolite genes, which need further detailed analyses. [ABSTRACT FROM AUTHOR]

Cyanobacteria are the most primitive photosynthetic organisms on the Earth. Their classification is traditionally based on morphological characters in both botanical and bacteriological systems. Due to the enormous diversity and the lack of clear diacritic morphological features between the closely related species, for resolving the evolutionary relationships and classification of Cyanobacteria during the last years is used a polyphasic approach including sequencing data. Although many molecular markers are improved, new suitable markers for resolving relationships within cyanobacteria at species and generic level are still needed. Our objective was to examine whether the sequences of the photosystem II proteins CP43 and CP47 are suitable markers for such purposes. Phylogenetic analyses based on the CP43 and CP47 amino acid sequences showed that most of the cyanobacterial species/strains belonging to different genera are clustered in separate clades supported by high bootstrap values. The comparison between the CP43 and CP47 trees, and the 16S phylogenetic trees showed that the CP43 and CP47 proteins are more suitable markers in resolving phylogenetic relationships within Cyanobacteria at generic and species level than the conserved 16S rRNA gene sequence. The correct taxonomic classification and identification of the cyanobacterial strains is very important for all studies related to the biological activity of cyanobacteria, their biotechnological application or in the management and monitoring of water. [ABSTRACT FROM AUTHOR]