40 research outputs found
ИСПОЛЬЗОВАНИЕ МЕТОДОВ СПЕКТРОСКОПИИ УФ-, ВИДИМОГО И БЛИЖНЕГО ИК-ДИАПАЗОНОВ ДЛЯ ОПРЕДЕЛЕНИЯ ОРИГИНАЛЬНОСТИ ВЫДЕРЖАННЫХ ВИННЫХ ДИСТИЛЛЯТОВ
Ultraviolet, visible and near infra-red spectroscopy is used for identification of the authenticity of matured wine distillates. The use of principal component analysis, the discriminant analysis, the classification trees and projection latent structures to broad-band transmission spectra of wine distillates allowed determining manufacturer and aging of wine distillates.Спектроскопия УФ-, видимого и ближнего ИК-диапазонов применена для определения оригинальности выдержанных винных дистиллятов. Использование метода главных компонент, дискриминантного анализа, построения деревьев классификации и регрессии на латентные структуры к широкополосным спектрам пропускания винных дистиллятов позволило определить производителя и возраст выдержки объектов исследования
Super-Resolution Dynamic Imaging of Dendritic Spines Using a Low-Affinity Photoconvertible Actin Probe
The actin cytoskeleton of dendritic spines plays a key role in morphological aspects of synaptic plasticity. The detailed analysis of the spine structure and dynamics in live neurons, however, has been hampered by the diffraction-limited resolution of conventional fluorescence microscopy. The advent of nanoscopic imaging techniques thus holds great promise for the study of these processes. We implemented a strategy for the visualization of morphological changes of dendritic spines over tens of minutes at a lateral resolution of 25 to 65 nm. We have generated a low-affinity photoconvertible probe, capable of reversibly binding to actin and thus allowing long-term photoactivated localization microscopy of the spine cytoskeleton. Using this approach, we resolve structural parameters of spines and record their long-term dynamics at a temporal resolution below one minute. Furthermore, we have determined changes in the spine morphology in response to pharmacologically induced synaptic activity and quantified the actin redistribution underlying these changes. By combining PALM imaging with quantum dot tracking, we could also simultaneously visualize the cytoskeleton and the spine membrane, allowing us to record complementary information on the morphological changes of the spines at super-resolution
Red Fluorescent Protein-Aequorin Fusions as Improved Bioluminescent Ca2+ Reporters in Single Cells and Mice
Bioluminescence recording of Ca2+ signals with the photoprotein aequorin does not require radiative energy input and can be measured with a low background and good temporal resolution. Shifting aequorin emission to longer wavelengths occurs naturally in the jellyfish Aequorea victoria by bioluminescence resonance energy transfer (BRET) to the green fluorescent protein (GFP). This process has been reproduced in the molecular fusions GFP-aequorin and monomeric red fluorescent protein (mRFP)-aequorin, but the latter showed limited transfer efficiency. Fusions with strong red emission would facilitate the simultaneous imaging of Ca2+ in various cell compartments. In addition, they would also serve to monitor Ca2+ in living organisms since red light is able to cross animal tissues with less scattering. In this study, aequorin was fused to orange and various red fluorescent proteins to identify the best acceptor in red emission bands. Tandem-dimer Tomato-aequorin (tdTA) showed the highest BRET efficiency (largest energy transfer critical distance R0) and percentage of counts in the red band of all the fusions studied. In addition, red fluorophore maturation of tdTA within cells was faster than that of other fusions. Light output was sufficient to image ATP-induced Ca2+ oscillations in single HeLa cells expressing tdTA. Ca2+ rises caused by depolarization of mouse neuronal cells in primary culture were also recorded, and changes in fine neuronal projections were spatially resolved. Finally, it was also possible to visualize the Ca2+ activity of HeLa cells injected subcutaneously into mice, and Ca2+ signals after depositing recombinant tdTA in muscle or the peritoneal cavity. Here we report that tdTA is the brightest red bioluminescent Ca2+ sensor reported to date and is, therefore, a promising probe to study Ca2+ dynamics in whole organisms or tissues expressing the transgene
Colloids as Mobile Substrates for the Implantation and Integration of Differentiated Neurons into the Mammalian Brain
Neuronal degeneration and the deterioration of neuronal communication lie at the origin of many neuronal disorders, and there have been major efforts to develop cell replacement therapies for treating such diseases. One challenge, however, is that differentiated cells are challenging to transplant due to their sensitivity both to being uprooted from their cell culture growth support and to shear forces inherent in the implantation process. Here, we describe an approach to address these problems. We demonstrate that rat hippocampal neurons can be grown on colloidal particles or beads, matured and even transfected in vitro, and subsequently transplanted while adhered to the beads into the young adult rat hippocampus. The transplanted cells have a 76% cell survival rate one week post-surgery. At this time, most transplanted neurons have left their beads and elaborated long processes, similar to the host neurons. Additionally, the transplanted cells distribute uniformly across the host hippocampus. Expression of a fluorescent protein and the light-gated glutamate receptor in the transplanted neurons enabled them to be driven to fire by remote optical control. At 1-2 weeks after transplantation, calcium imaging of host brain slice shows that optical excitation of the transplanted neurons elicits activity in nearby host neurons, indicating the formation of functional transplant-host synaptic connections. After 6 months, the transplanted cell survival and overall cell distribution remained unchanged, suggesting that cells are functionally integrated. This approach, which could be extended to other cell classes such as neural stem cells and other regions of the brain, offers promising prospects for neuronal circuit repair via transplantation of in vitro differentiated, genetically engineered neurons
Legionella pneumophila Secretes a Mitochondrial Carrier Protein during Infection
The Mitochondrial Carrier Family (MCF) is a signature group of integral membrane proteins that transport metabolites across the mitochondrial inner membrane in eukaryotes. MCF proteins are characterized by six transmembrane segments that assemble to form a highly-selective channel for metabolite transport. We discovered a novel MCF member, termed Legionella nucleotide carrier Protein (LncP), encoded in the genome of Legionella pneumophila, the causative agent of Legionnaire's disease. LncP was secreted via the bacterial Dot/Icm type IV secretion system into macrophages and assembled in the mitochondrial inner membrane. In a yeast cellular system, LncP induced a dominant-negative phenotype that was rescued by deleting an endogenous ATP carrier. Substrate transport studies on purified LncP reconstituted in liposomes revealed that it catalyzes unidirectional transport and exchange of ATP transport across membranes, thereby supporting a role for LncP as an ATP transporter. A hidden Markov model revealed further MCF proteins in the intracellular pathogens, Legionella longbeachae and Neorickettsia sennetsu, thereby challenging the notion that MCF proteins exist exclusively in eukaryotic organisms
Anaplasma phagocytophilum Ats-1 Is Imported into Host Cell Mitochondria and Interferes with Apoptosis Induction
Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis, infects human neutrophils and inhibits mitochondria-mediated apoptosis. Bacterial factors involved in this process are unknown. In the present study, we screened a genomic DNA library of A. phagocytophilum for effectors of the type IV secretion system by a bacterial two-hybrid system, using A. phagocytophilum VirD4 as bait. A hypothetical protein was identified as a putative effector, hereby named Anaplasma translocated substrate 1 (Ats-1). Using triple immunofluorescence labeling and Western blot analysis of infected cells, including human neutrophils, we determined that Ats-1 is abundantly expressed by A. phagocytophilum, translocated across the inclusion membrane, localized in the host cell mitochondria, and cleaved. Ectopically expressed Ats-1 targeted mitochondria in an N-terminal 17 residue-dependent manner, localized in matrix or at the inner membrane, and was cleaved as native protein, which required residues 55–57. In vitro-translated Ats-1 was imported in a receptor-dependent manner into isolated mitochondria. Ats-1 inhibited etoposide-induced cytochrome c release from mitochondria, PARP cleavage, and apoptosis in mammalian cells, as well as Bax-induced yeast apoptosis. Ats-1(55–57) had significantly reduced anti-apoptotic activity. Bax redistribution was inhibited in both etoposide-induced and Bax-induced apoptosis by Ats-1. Taken together, Ats-1 is the first example of a bacterial protein that traverses five membranes and prevents apoptosis at the mitochondria
Computational modelling of non-stationary processes of the internal supersonic gas flow on the example of the exit of the rocket from the starting container
Пешков Руслан Александрович. Аспирант кафедры «Летательные аппараты и автоматические установки», Южно-Уральский государственный университет. Область научных интересов – численное моделирование газодинамических течений, динамика старта. E-mail: [email protected]
Ruslan A. Peshkov. Post-graduate student of «Aircrafts and Automatic Installations» department, South Ural State University. Professional interests – numerical modeling of gas flow, dynamics of start. E-mail: [email protected]
Сидельников Рудольф Васильевич. Кандидат технических наук, доцент кафедры «Летательные аппараты и автоматические установки», Южно-Уральский государственный университет. Область научных интересов – динамика механических систем, аэрогазодинамика летательных аппаратов. E-mail: [email protected]
Rudolf V. Sidel'nikov. The candidate of engineering science, assistant professor of «Aircrafts and Automatic Installations» department, South Ural State University. Professional interests – dynamics of mechanical systems, aerodynamics of aircraft. E-mail: [email protected]
Дегтярь Владимир Григорьевич. Доктор технических наук, профессор, заведующий кафедрой «Летательные аппараты и автоматические установки», Южно-Уральский государственный университет. Область научных интересов – системное проектирование летательных аппаратов, гидродинамика, механика конструкций из композиционных материалов. Тел: 267-94-57; e-mail: [email protected]
Vladimir G. Degtyar'. The doctor of engineering science, professor, the Head of «Aircrafts and Automatic Installations» department, South Ural state university. Professional interests – system design of aircraft, fluid dynamics, structural mechanics of composite materials. Tel: 267-94-57; e-mail: [email protected]Разработаны методики расчета нестационарных процессов внутренних сверхзвуковых течений газа на примере выхода ракеты из пускового контейнера. С помощью различных методик исследования удалось провести анализ влияния конструктивных параметров пускового контейнера на скорость движения ракеты не только качественно, но и количественно. Эти же методики позволили оценить влияние внешнего температурного фактора на параметры выхода ракеты из транспортно-пускового контейнера.
Methods of calculations was developed. This method include non-stationary processes of internal supersonic gas flow on an example of an exit of the rocket from the starting container. By means of various techniques of research it was possible to carry out the analysis of influence of design data of the starting container for speed of movement of the rocket not only qualitatively, but also quantitatively. The same techniques allowed to estimate influence of an external temperature factor on parameters of an exit of the rocket from the starting container