Cellular Uptake of Phase-Separating Peptide Coacervates.

Peptide coacervates self-assembling via liquid-liquid phase separation are appealing intracellular delivery vehicles of macromolecular therapeutics (proteins, DNA, mRNA) owing to their non-cytotoxicity, high encapsulation capacity, and efficient cellular uptake. However, the mechanisms by which these viscoelastic droplets cross the cellular membranes remain unknown. Here, using multimodal imaging, data analytics, and biochemical inhibition assays, we identify the key steps by which droplets enter the cell.

Gentisate 1,2-dioxygenase from the gram-positive bacteria Rhodococcus opacus 1CP: Identical active sites vs. different substrate selectivities.

Gentisate 1,2-dioxygenases belong to the class III ring-cleaving dioxygenases catalyzing key reactions of aromatic compounds degradation by aerobic microorganisms. In the present work, the results of complete molecular, structural, and functional investigations of the gentisate 1,2-dioxygenase (rho-GDO) from a gram-positive bacterium Rhodococcus opacus 1CP growing on 3-hydroxybenzoate as a sole source of carbon and energy are presented. The purified enzyme showed a narrow substrate specificity.

Laccase isoform diversity in basidiomycete Lentinus strigosus 1566: Potential for phenylpropanoid polymerization.

Three laccase isoforms with different physicochemical properties could be purified from culture liquid of basidiomycete Lentinus strigosus 1566 obtained during submerged cultivation. The purified laccases possessed individual selectivity in relation to different phenolic compounds. Laccases I, II, and III (59, 65, and 61 kDa respectively) were more active in acidic conditions at around 70 °C.

A new simple method for quantification and locating P and N reserves in microalgal cells based on energy-filtered transmission electron microscopy (EFTEM) elemental maps.

We established a new simple approach to study phosphorus (P) and nitrogen (N) reserves at subcellular level potentially applicable to various types of cells capable of accumulating P- and/or N-rich inclusions. Here, we report on using this approach for locating and assessing the abundance of the P and N reserves in microalgal and cyanobacterial cells. The approach includes separation of the signal from P- or N-rich structures from noise on the energy-filtered transmission electron microscopy (EFTEM) P- or N-maps.

Folic acid-capped PEGylated magnetic nanoparticles enter cancer cells mostly via clathrin-dependent endocytosis.

Background: This work is focused on mechanisms of uptake in cancer cells of rationally designed, covalently assembled nanoparticles, made of superparamagnetic iron oxide nanoparticles (SPIONs), fluorophores (doxorubicin or Nile Blue), polyethylene glycol (PEG) and folic acid (FA), referred hereinafter as SFP-FA.

Methods: SFP-FA were characterized by DLS, zetametry and fluorescence spectroscopy. The SFP-FA uptake in cancer cells was monitored using fluorescence-based methods like fluorescence-assisted cell sorting, CLSM with single-photon and two-photon excitation.

Versatility of the green microalga cell vacuole function as revealed by analytical transmission electron microscopy.

Vacuole is a multifunctional compartment central to a large number of functions (storage, catabolism, maintenance of the cell homeostasis) in oxygenic phototrophs including microalgae. Still, microalgal cell vacuole is much less studied than that of higher plants although knowledge of the vacuolar structure and function is essential for understanding physiology of nutrition and stress tolerance of microalgae. Here, we combined the advanced analytical and conventional transmission electron microscopy methods to obtain semi-quantitative, spatially resolved at the subcellular level information on elemental composition of the cell vacuoles in several free-living and symbiotic chlorophytes.

Electroanalysis of Shewanella oneidensis MR-1.

Electrochemical parameters of bacterial cells Shewanella oneidensis MR-1 were investigated. For registration of the direct electron transfer between S. oneidensis MR-1 and electrode, bacterial cells were pretreated with didodecyldimethylammonium bromide (DDAB), a synthetic membrane-like substance of polycationic nature that exhibits membrane-loosening properties.

[Study of some aspects of the mechanism of bacterial synthesis of silver sulfide nanoparticles by mMetal-reducing bacteria Shewanella oneidensis MR-1].

In the present work it was shown that biosynthesis of silver sulfide nanoparticles from silver nitrate and sodium thiosulfate solutions of millimolar concentration occurs efficiently by living Shewanella oneidensis MR-1 cells, as well as by ultrasonically-disrupted cells and by the membrane fraction of the cells. The size of nanoparticles synthesized in the presence of living cells was 7.8 ± 1.

[application of the analytical transmission electron microscopy techniques for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in mammalian cells].

This work represents the results of the study on applicability of the modern methods of analytical transmission electron microscopy for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in A549 cell, human lung adenocarcinoma cell line. A comparative analysis of images of the nanoparticles in the cells obtained in the bright field mode of transmission electron microscopy, under dark-field scanning transmission electron microscopy and high-angle annular dark field scanning transmission electron was performed. For identification of nanoparticles in the cells the analytical techniques, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy, were compared when used in the mode of obtaining energy spectrum from different particles and element mapping.

Classification of rhodopsin structures by modern methods of structural bioinformatics.

We report a classification of the crystallographic structures of bovine and squid rhodopsins corresponding to different stages of their photocycles. Using the resource Protein (Structure) Comparison, Knowledge, Similarity, and Information server (ProCKSI, http://www.procksi.

[A new method for quantitative estimation of the number of virus particles].

[In the present work virus particles of live mumps virus vaccine widely used for vaccination in Russia have been detected and visualized by atomic force microscopy. For quantitative estimation of the number of observed virus particles the special method has been proposed. The presence of protein component of the virus in vaccine was tested by ELISA and dot-blot analysis.