Measurement of large ribosomal subunit size in cytoplasm and nucleus of living human cells.

Ribosomes are the most essential macromolecules in cells, as they serve as production lines for every single protein. Here, we address the demand to study ribosomes in living human cells by applying time-resolved microscopy. We show that oxazole yellow iodide (YO-PRO-1 dye) intercalates tRNA and rRNA with a determined equilibrium constant of 3.

A novel process for transcellular hemoglobin transport from macrophages to cancer cells.

Hemoglobin (Hb) performs its physiological function within the erythrocyte. Extracellular Hb has prooxidative and proinflammatory properties and is therefore sequestered by haptoglobin and bound by the CD163 receptor on macrophages. In the present study, we demonstrate a novel process of Hb uptake by macrophages independent of haptoglobin and CD163.

Starvation induces diffusion hindrance at the nanoscale in mammalian cells.

Prolonged starvation leads to acute stress, inducing a state of cellular dormancy with reduced energy consumption. Our research reveals that nutrient deprivation halts the movement of large ribosomal subunits, trapping them in a gel-like structure within the cytoplasm of surviving cells. This effect is due to water efflux from cells, causing a decrease in cell volume to half the original volume.

Physicochemical Perspective of Biological Heterogeneity.

The vast majority of chemical processes that govern our lives occur within living cells. At the core of every life process, such as gene expression or metabolism, are chemical reactions that follow the fundamental laws of chemical kinetics and thermodynamics. Understanding these reactions and the factors that govern them is particularly important for the life sciences.

Rotational and translational diffusion of biomolecules in complex liquids and HeLa cells.

Diffusive motion accompanies many physical and biological processes. The Stokes-Sutherland-Einstein relation for the translational diffusion coefficient, , agrees with experiments done in simple fluids but fails for complex fluids. Moreover, the interdependence between and rotational diffusion coefficient, , also deviates in complex fluids from the classical relation of / = 4/3 known in simple fluids.

Surface and composition effects on the biphasic cytotoxicity of nanocomposites synthesized using leaf extracts.

The Malus sylvestris L. (LE1), Pinus sylvestris L. (LE2), and Sorbus aucuparia L.

Living Cell as a Self-Synchronized Chemical Reactor.

Thermal fluctuations power all processes inside living cells. Therefore, these processes are inherently random. However, myriad multistep chemical reactions act in concerto inside a cell, finally leading to this chemical reactor's self-replication.

Comment on "Fluorimetric sensing of ATP in water by an imidazolium hydrazone based sensor" by S. Farshbaf and P. Anzenbacher Jr., , 2019, , 1770.

In the paper, "Fluorimetric sensing of ATP in water by an imidazolium hydrazone based sensor," Farshbaf and Anzenbacher presented the application of bisantrene as a fluorescent ATP sensor in organic-inorganic mixtures of solvents. Encouraged by the results presented in the parent study, we aimed to apply this strategy for physiologically relevant water-based buffers and - preferably - intracellular application. Here we present the results of our investigations and point to the limitations of bisantrene applications as the ATP sensor.

Cellular Uptake of Bevacizumab in Cervical and Breast Cancer Cells Revealed by Single-Molecule Spectroscopy.

Bevacizumab is a biological drug that is now extensively studied in clinics against various types of cancer. Although bevacizumab's action is preferably extracellular, there are reports suggesting its internalization into cancer cells, consequently decreasing its therapeutic potential. Here we are solving this issue by applying fluorescence correlation spectroscopy in living cells.

Entanglement of polymer chains in hypertonic medium enhances the delivery of DNA and other biomacromolecules into cells.

Hypothesis: Most experimental procedures applied in modern biology involve cargo delivering into cells. One of the ways to cargo introduction is osmotic-mediated intracellular vesicle swelling. However, its widespread use was hindered due to cargo size (<10 nm) and cell-type-related restrictions.

Electrochemically Synthesized Polyacrylamide Gel and Core-Shell Nanoparticles for 3D Cell Culture Formation.

Biocompatible polyacrylamide gel and core-shell nanoparticles (NPs) were synthesized using a one-step electrochemically initiated gelation. Constant-potential electrochemical decomposing of ammonium persulfate initiated the copolymerization of -isopropyl acrylamide, methacrylic acid, and ,'-methylenebisacrylamide monomers. This decomposing potential and monomers' concentrations were optimized to prepare gel NPs and thin gel film-grafted core-shell NPs.

Cytotoxicity and oxidative stress induced by atmospheric mono-nitrophenols in human lung cells.

Nitrophenols (NPs) are hazardous pollutants found in various environmental matrices, including ambient fine particulate matter (PM), agricultural residues, rainwater, wildfires, and industrial wastes. This study showed for the first time the effect of three pure nitrophenols and their mixture on human lung cells to provide basic understanding of the NP influence on cell elements and processes. We identified NPs in ambient PM and secondary organic aerosol (SOA) particles generated from the photooxidation of monocyclic aromatic hydrocarbons in the U.

Quantitative analysis of biochemical processes in living cells at a single-molecule level: a case of olaparib-PARP1 (DNA repair protein) interactions.

Quantitative description of biochemical processes inside living cells and at single-molecule levels remains a challenge at the forefront of modern instrumentation and spectroscopy. This paper demonstrates such single-cell, single-molecule analyses performed to study the mechanism of action of olaparib - an up-to-date, FDA-approved drug for germline-BRCA mutated metastatic breast cancer. We characterized complexes formed with PARPi-FL - fluorescent analog of olaparib and in cancer cells using the advanced fluorescent-based method: Fluorescence Correlation Spectroscopy (FCS) combined with a length-scale dependent cytoplasmic/nucleoplasmic viscosity model.

Cellular delivery of dinucleotides by conjugation with small molecules: targeting translation initiation for anticancer applications.

Targeting cap-dependent translation initiation is one of the experimental approaches that could lead to the development of novel anti-cancer therapies. Synthetic dinucleoside 5',5'-triphosphates cap analogs are potent antagonists of eukaryotic translation initiation factor 4E (eIF4E) and could counteract elevated levels of eIF4E in cancer cells; however, transformation of these compounds into therapeutic agents remains challenging - they do not easily penetrate into cells and are susceptible to enzymatic cleavage. Here, we tested the potential of several small molecule ligands - folic acid, biotin, glucose, and cholesterol - to deliver both hydrolyzable and cleavage-resistant cap analogs into cells.

Toxicological Responses of α-Pinene-Derived Secondary Organic Aerosol and Its Molecular Tracers in Human Lung Cell Lines.

Secondary organic aerosol (SOA) is a major component of airborne fine particulate matter (PM) that contributes to adverse human health effects upon inhalation. Atmospheric ozonolysis of α-pinene, an abundantly emitted monoterpene from terrestrial vegetation, leads to significant global SOA formation; however, its impact on pulmonary pathophysiology remains uncertain. In this study, we quantified an increasing concentration response of three well-established α-pinene SOA tracers (pinic, pinonic, and 3-methyl-1,2,3-butanetricarboxylic acids) and a full mixture of α-pinene SOA in A549 (alveolar epithelial carcinoma) and BEAS-2B (bronchial epithelial normal) lung cell lines.

Quantifying Nanoscale Viscosity and Structures of Living Cells Nucleus from Mobility Measurements.

Understanding the mobility of nano-objects in the eukaryotic cell nucleus, at multiple length-scales, is essential for dissecting nuclear structure-function relationships both in space and in time. Here, we demonstrate, using single-molecule fluorescent correlation spectroscopies, that motion of inert probes (proteins, polymers, or nanoparticles) with diameters ranging from 2.6 to 150 nm is mostly unobstructed in a nucleus.

Transport of nanoprobes in multicellular spheroids.

The efficient delivery of drugs to cells depends on their diffusion through the extracellular matrix (ECM) of tissues. Here we present a study on the diffusion of nanoprobes of radius from 1 nm to over 100 nm in the ECM of spheroids of three cell types (HeLa, MCF-7 and fibroblasts). We quantified the nanoparticle transport in the spheroids' proliferating zone.

Nanoscale Viscosity of Cytoplasm Is Conserved in Human Cell Lines.

Metabolic reactions in living cells are limited by diffusion of reagents in the cytoplasm. Any attempt to quantify the kinetics of biochemical reactions in the cytosol should be preceded by careful measurements of the physical properties of the cellular interior. The cytoplasm is a complex, crowded fluid characterized by effective viscosity dependent on its structure at a nanoscopic length scale.

Stability of cytoplasmic nanoviscosity during cell cycle of HeLa cells synchronized with Aphidicolin.

Nanoviscosity of the cytoplasm is a key factor affecting diffusion of biomolecules and - as a consequence - rates of biochemical reactions in a cell. Nanoviscosity is an outcome of variable chemical and structural factors, which can temporarily change with cell-cycle associated changes of intracellular architecture. Thus, the question arises, whether rates of biochemical reactions depend on the point of cell cycle.

Determination of oligomerization state of Drp1 protein in living cells at nanomolar concentrations.

Biochemistry in living cells is an emerging field of science. Current quantitative bioassays are performed ex vivo, thus equilibrium constants and reaction rates of reactions occurring in human cells are still unknown. To address this issue, we present a non-invasive method to quantitatively characterize interactions (equilibrium constants, K) directly within the cytosol of living cells.

Insight into the fission mechanism by quantitative characterization of Drp1 protein distribution in the living cell.

One of the main players in the process of mitochondrial fragmentation is dynamin-related protein 1 (Drp1), which assembles into a helical ring-like structure on the mitochondria and facilitates fission. The fission mechanism is still poorly understood and detailed information concerning oligomeric form of Drp1, its cellular distribution and the size of the fission complex is missing. To estimate oligomeric forms of Drp1 in the cytoplasm and on the mitochondria, we performed a quantitative analysis of Drp1 diffusion and distribution in gene-edited HeLa cell lines.

Establishment of Microfluidic Spheroid Cultures for Biomedical Applications.

Multicellular spheroid is a three-dimensional (3D) cell culture model that mimics cancer tumor environment. Its widespread use for anticancer therapy evaluation is nowadays limited by accessibility of 3D compatible assays. Here, a microfluidic system for spheroid formation, culture and analysis is presented.

Apparent Anomalous Diffusion in the Cytoplasm of Human Cells: The Effect of Probes' Polydispersity.

This work, based on in vivo and in vitro measurements, as well as in silico simulations, provides a consistent analysis of diffusion of polydisperse nanoparticles in the cytoplasm of living cells. Using the example of fluorescence correlation spectroscopy (FCS), we show the effect of polydispersity of probes on the experimental results. Although individual probes undergo normal diffusion, in the ensemble of probes, an effective broadening of the distribution of diffusion times occurs-similar to anomalous diffusion.