Publications by authors named "Ermakova Y"

Thermogenetics is a promising neuromodulation technique based on the use of heat-sensitive ion channels. However, on the way to its clinical application, a number of questions have to be addressed. First, to avoid immune response in future human applications, human ion channels should be studied as thermogenetic actuators.

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Recently, progress has been made in fabricating diamond-based scintillators with integrated rare-earth luminescent particles. These luminescent particles are integrated into the bulk of diamond during their synthesis by chemical vapor deposition (CVD). However, the growth conditions include a chemically aggressive plasma environment and elevated temperatures, which results in the partial degradation of particles and a decrease in the intensity of their luminescence.

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Is to establish the possibility of studying the vitreous body of the eye from embalmed corpses using the spin probe method to develop diagnostic criteria for the prescription of death coming. The article presents data showing the possibility of diagnosing the prescription of death coming by the method of spin probes with the examination of the vitreous body of the eye from embalmed corpses. A total of 510 spectra obtained during incubation of the 1-oxyl-4-oxo-2.

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The article is devoted to the history of the formation and development of the department of forensic medicine named after P.A. Minakov of the medical faculty of the Pirogov russian national research medical university for 115 years.

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The major challenge in optical ceramic technology is the quality of the starting precursor powder for pressing, which is a key element in the optical ceramic industry. One express and helpful technique for the estimation of powder quality is the estimation of the quantum yield of up-conversion luminescence; therefore precursor powders must exhibit high values of up-conversion luminescence efficiency. Single-phase solid solutions based on strontium fluoride doped with ytterbium and erbium were synthesised by co-precipitation from aqueous solutions using sodium fluoride, potassium fluoride and ammonium fluoride as fluorinating agents.

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The delivery of small molecule fluorophores with minimal compartmentalization is currently one of the most critical technical problems in intracellular labelling. Here we introduce sulfonated and phosphonated coumarin dyes, demonstrate rapid cell entry via a prodrug approach, and show a lack of interaction with membranes, organelles, or other compartments. The dyes show no specific localization and are evenly distributed in the cells.

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Article Synopsis
  • * The study uses advanced genetically encoded biosensors to observe intracellular pH and reactive oxygen species (ROS) dynamics during these processes in both cultured neurons and experimental stroke in rats.
  • * Findings reveal a significant acidosis in the brain tissue almost immediately during the ischemic core, but notable ROS generation was only observed 24 hours later, indicating a disconnect between cell culture and actual metabolic processes in vivo.
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Hydrogen peroxide (HO) is a key redox intermediate generated within cells. Existing probes for HO have not solved the problem of detection of the ultra-low concentrations of the oxidant: these reporters are not sensitive enough, or pH-dependent, or insufficiently bright, or not functional in mammalian cells, or have poor dynamic range. Here we present HyPer7, the first bright, pH-stable, ultrafast, and ultrasensitive ratiometric HO probe.

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We demonstrate an accurate quantitative characterization of absolute two- and three-photon absorption (2PA and 3PA) action cross sections of a genetically encodable fluorescent marker Sypher3s. Both 2PA and 3PA action cross sections of this marker are found to be remarkably high, enabling high-brightness, cell-specific two- and three-photon fluorescence brain imaging. Brain imaging experiments on sliced samples of rat's cortical areas are presented to demonstrate these imaging modalities.

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Here we present a set of fluorescent cages prepared by tethering fluorescent dyes to a photolabile group. The developed molecules enable caging of signalling lipids, their delivery to specific cellular membranes, with further imaging, quantification, and controlled photorelease of active lipids in living cells.

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Hydrogen peroxide (HO) plays an important role in modulating cell signaling and homeostasis in live organisms. The HyPer family of genetically encoded indicators allows the visualization of HO dynamics in live cells within a limited field of view. The visualization of HO within a whole organism with a single cell resolution would benefit from a slowly reducible fluorescent indicator that integrates the HO concentration over desired time scales.

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Reactive oxygen species (ROS) are involved in regulating normal physiological cell functions as second messengers as well as nonspecific damage of biomolecules in a pathological process known as oxidative stress. The HyPer family of genetically encoded probes are a useful noninvasive tool for monitoring the real-time dynamics of ROS in individual cells or model organisms. HyPer, the first genetically encoded probe for detection of hydrogen peroxide (HO), is oxidized with high specificity and sensitivity by HO, leading to ratiometric changes in the fluorescence excitation spectrum of the probe.

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Cellular antioxidant systems control the levels of hydrogen peroxide (HO) within cells. Multiple theoretical models exist that predict the diffusion properties of HO depending on the rate of HO generation and amount and reaction rates of antioxidant machinery components. Despite these theoretical predictions, it has remained unknown how antioxidant systems shape intracellular HO gradients.

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The authors consider the selected stages in the development of the system of continuous medical education in the field of forensic medicine and forensic medical expertise as well as the contribution of the Department of Forensic Medicine of N.I. Pirogov Russian National Research Medical University to its practical implementation.

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Redox-sensitive fluorescent proteins (roFPs) are a powerful tool for imaging intracellular redox changes. The structure of these proteins contains a pair of cysteines capable of forming a disulfide upon oxidation that affects the protein conformation and spectral characteristics. To date, a palette of such biosensors covers the spectral range from blue to red.

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Thermogenetics is a promising innovative neurostimulation technique, which enables robust activation of single neurons using thermosensitive cation channels and IR stimulation. The main advantage of IR stimulation compared to conventional visible light optogenetics is the depth of penetration (up to millimeters). Due to physiological limitations, thermogenetic molecular tools for mammalian brain stimulation remain poorly developed.

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This article was designed to consider the problem of diagnostics of prescription of death coming taking account of the present-day level of the forensic medical activities with special reference to the disadvantages of the application of the classical and laboratory diagnostic methods for the establishment of prescription of death coming. The priority approaches to addressing this problem are highlighted.

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Novel fluorogenic dyes based on the GFP chromophore are developed. The compounds contain a pyridinium ring instead of phenolate and feature large Stokes shifts and solvent-dependent variations in the fluorescence quantum yield. Electronic structure calculations explain the trends in solvatochromic behavior in terms of the increase of the dipole moment upon excited-state relaxation in polar solvents associated with the changes in bonding pattern in the excited state.

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We designed a genetically encoded ratiometric fluorescent probe, SypHer3s, with enhanced brightness and optimized pK, which responds to pH changes in different cellular compartments. SypHer3s was successfully utilized for imaging the pH dynamics in mitochondria of living neurons and in quantitative pH measurement in zebrafish embryos.

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Article Synopsis
  • Thermogenetics is an innovative neurostimulation technique that uses thermosensitive TRP cation channels to activate neurons.
  • This study demonstrates rapid and reproducible activation of snake TRPA1 channels in various cell types and live organisms using infrared (IR) laser radiation.
  • The research introduces a fibre-optic probe that enables precise temperature measurements at a single-cell level, allowing for mild heating and safe neuronal activation without damaging the cells.
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Optically detected electron spin resonance in fiber-coupled nitrogen-vacancy (NV) centers of diamond is used to demonstrate a fiber-optic quantum thermometry of individual thermogenetically activated neurons. Laser-induced temperature variations read out from single neurons with the NV-diamond fiber sensor are shown to strongly correlate with the fluorescence of calcium-ion sensors, serving as online indicators of the inward Ca current across the cell membrane of neurons expressing transient receptor potential (TRP) cation channels. Local laser heating above the TRP-channel activation threshold is shown to reproducibly evoke robust action potentials, visualized by calcium-ion-sensor-aided fluorescence imaging and detected as prominent characteristic waveforms in the time-resolved response of fluorescence Ca sensors.

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Thermal activation of transient receptor potential (TRP) cation channels is one of the most striking examples of temperature-controlled processes in cell biology. As the evidence indicating the fundamental role of such processes in thermosensation builds at a fast pace, adequately accurate tools that would allow heat receptor logic behind thermosensation to be examined on a single-cell level are in great demand. Here, we demonstrate a specifically designed fiber-optic probe that enables thermal activation with simultaneous online thermometry of individual cells expressing genetically encoded TRP channels.

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Background: SypHer is a genetically encoded fluorescent pH-indicator with a ratiometric readout, suitable for measuring fast intracellular pH shifts. However, the relatively low brightness of the indicator limits its use.

Methods: Here we designed a new version of pH-sensor called SypHer-2, which has up to three times brighter fluorescence in cultured mammalian cells compared to the SypHer.

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Ageing and lifespan of organisms are determined by complicated interactions between their genetics and the environment, but the cellular mechanisms remain controversial. There have been a number of studies suggesting that cellular energy metabolism and free radical dynamics affect lifespan, implicating mitochondrial function. Recently, Shen provided apparent mechanistic insight by reporting that mitochondrial oscillations of ‘free radical production’, called ‘mitoflashes’, in the pharynx of 3-day old correlated inversely with lifespan.

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Reactive oxygen species (ROS) are conserved regulators of numerous cellular functions, and overproduction of ROS is a hallmark of various pathological processes. Genetically encoded fluorescent probes are unique tools to study ROS production in living systems of different scale and complexity. However, the currently available recombinant redox sensors have green emission, which overlaps with the spectra of many other probes.

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