Localisation and interactions of the Vipp1 protein in cyanobacteria

Biotechnology and Biological Sciences Research Council. Grant Number: BB/G021856. Deutsche Forschungsgemeinschaft. Grant Number: FOR 929, SCHN 690/3-1. European Commission. Grant Number: FP7-PEOPLE-2009-IEF 254575. NFR. Grant Numbers: 192436, 197119. OCISB. Royal Society and Engineering and Physical Sciences Research Council. Grant Number: EP/G0061009/

MESENCHYMAL STROMAL CELLS IN CORRECTION OF NEUROLOGICAL DEFICIT AND MORPHOLOGICAL CHANGES IN THE RAT MODEL OF FOCAL CEREBRAL LESIONS INDUCED BY VENOUS BLOOD FLOW DISORDER

The paper presents the results of assessing the effect of bone marrow-derived mesenchymal stromal cells (MSCs) on the severity of neurological deficit and the brain morphology and function in a model of focal lesions induced by a venous blood flow disorder. Cerebral lesions were induced in Wistar rats by coagulation of the superior sagittal sinus followed by coagulation of cortical veins in the left parietotemporal region. MSCs were injected intravenously on days 1 and 7, and the dynamics of neurological disorders and morphological changes were assessed at 7, 14 and 21 days in comparison to controls. MSCs infusion was accompanied by a significant reduction. in neurological deficit, the most pronounced with MSCs injections on day 1. Morphological investigation of the damaged region have shown that the administration of MSCs led to a decrease in the area of necrosis, stimulation of angiogenesis, and improvement of structural and cellular parameters as compared to the control group. As a result, by day 21 the area of necrosis in animals with MSC transplantation was replaced by glial-mesodermal scar, whereas the scar formation in control animals was less pronounced, and in some cases was accompanied by cystic transformation. Transplantation of MSCs has a positive effect on neurological and morphofunctional recovery of the brain in experimental animal models of cerebral venous circulation disorders

CLINICAL EFFECTS OF MESENCHYMAL STROMAL CELLS IN LYMPHOMA PATIENTS WITH AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION

The clinical and laboratory effects of bone-marrow derived mesenchymal stromal cells (MSC) in patients with malignant lymphomas following autologous hematopoietic stem cell transplantation (auto-HSCT) have been investigated. Co-transplantation of MSC in average dose of 0,178 106/kg was conducted in 74 patients with auto-HSCT. The control group included 83 patients eligible for standard HSCT. We revealed the decreasing of the period of neutropenia and thrombocytopenia when hematopoietic stem cells were co-transplanted with low doses ex vivo expanded autologous MSC. Patients with MSC co-transplantation were differed by more effective early lymphocyte recovery. At the same time MSC co-transplantation did not increase the incidence of infectious complications and cases of renal and. hepatic toxicity. Patients with MSC co-transplantation did not differ from opposite group by 5-year overall survival, but were characterized by significantly better progression-free survival

Importance of Post-Translational Modifications for Functionality of a Chloroplast-Localized Carbonic Anhydrase (CAH1) in Arabidopsis thaliana

Background: The Arabidopsis CAH1 alpha-type carbonic anhydrase is one of the few plant proteins known to be targeted to the chloroplast through the secretory pathway. CAH1 is post-translationally modified at several residues by the attachment of N-glycans, resulting in a mature protein harbouring complex-type glycans. The reason of why trafficking through this non-canonical pathway is beneficial for certain chloroplast resident proteins is not yet known. Therefore, to elucidate the significance of glycosylation in trafficking and the effect of glycosylation on the stability and function of the protein, epitope-labelled wild type and mutated versions of CAH1 were expressed in plant cells. Methodology/Principal Findings: Transient expression of mutant CAH1 with disrupted glycosylation sites showed that the protein harbours four, or in certain cases five, N-glycans. While the wild type protein trafficked through the secretory pathway to the chloroplast, the non-glycosylated protein formed aggregates and associated with the ER chaperone BiP, indicating that glycosylation of CAH1 facilitates folding and ER-export. Using cysteine mutants we also assessed the role of disulphide bridge formation in the folding and stability of CAH1. We found that a disulphide bridge between cysteines at positions 27 and 191 in the mature protein was required for correct folding of the protein. Using a mass spectrometric approach we were able to measure the enzymatic activity of CAH1 protein. Under circumstances where protein N-glycosylation is blocked in vivo, the activity of CAH1 is completely inhibited. Conclusions/Significance: We show for the first time the importance of post-translational modifications such as N-glycosylation and intramolecular disulphide bridge formation in folding and trafficking of a protein from the secretory pathway to the chloroplast in higher plants. Requirements for these post-translational modifications for a fully functional native protein explain the need for an alternative route to the chloroplast.This work was supported by the Swedish Research Council (VR), the Kempe Foundations and Carl Tryggers Foundation to GS, and grant numbers BIO2006-08946 and BIO2009-11340 from the Spanish Ministerio de Ciencia e Innovación (MICINN) to A

On-line mass spectrometry: membrane inlet sampling

Significant insights into plant photosynthesis and respiration have been achieved using membrane inlet mass spectrometry (MIMS) for the analysis of stable isotope distribution of gases. The MIMS approach is based on using a gas permeable membrane to enable the entry of gas molecules into the mass spectrometer source. This is a simple yet durable approach for the analysis of volatile gases, particularly atmospheric gases. The MIMS technique strongly lends itself to the study of reaction flux where isotopic labeling is employed to differentiate two competing processes; i.e., O2 evolution versus O2 uptake reactions from PSII or terminal oxidase/rubisco reactions. Such investigations have been used for in vitro studies of whole leaves and isolated cells. The MIMS approach is also able to follow rates of isotopic exchange, which is useful for obtaining chemical exchange rates. These types of measurements have been employed for oxygen ligand exchange in PSII and to discern reaction rates of the carbonic anhydrase reactions. Recent developments have also engaged MIMS for online isotopic fractionation and for the study of reactions in inorganic systems that are capable of water splitting or H2 generation. The simplicity of the sampling approach coupled to the high sensitivity of modern instrumentation is a reason for the growing applicability of this technique for a range of problems in plant photosynthesis and respiration. This review offers some insights into the sampling approaches and the experiments that have been conducted with MIMS

Трансплантация аутологичных костномозговых клеток в лечении церебрального инсульта

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Analytical approaches to photobiological hydrogen production in unicellular green algae

Several species of unicellular green algae, such as the model green microalga Chlamydomonas reinhardtii, can operate under either aerobic photosynthesis or anaerobic metabolism conditions. A particularly interesting metabolic condition is that of “anaerobic oxygenic photosynthesis”, whereby photosynthetically generated oxygen is consumed by the cell’s own respiration, causing anaerobiosis in the culture in the light, and induction of the cellular “hydrogen metabolism” process. The latter entails an alternative photosynthetic electron transport pathway, through the oxygen-sensitive FeFe-hydrogenase, leading to the light-dependent generation of molecular hydrogen in the chloroplast. The FeFe-hydrogenase is coupled to the reducing site of photosystem-I via ferredoxin and is employed as an electron-pressure valve, through which electrons are dissipated, thus permitting a sustained electron transport in the thylakoid membrane of photosynthesis. This hydrogen gas generating process in the cells offers testimony to the unique photosynthetic metabolism that can be found in many species of green microalgae. Moreover, it has attracted interest by the biotechnology and bioenergy sectors, as it promises utilization of green microalgae and the process of photosynthesis in renewable energy production. This article provides an overview of the principles of photobiological hydrogen production in microalgae and addresses in detail the process of induction and analysis of the hydrogen metabolism in the cells. Furthermore, methods are discussed by which the interaction of photosynthesis, respiration, cellular metabolism, and H(2) production in Chlamydomonas can be monitored and regulated

Light-induced structural changes and the site of O=O bond formation in PSII caught by XFEL

Photosystem II (PSII) is a huge membrane-protein complex consisting of 20 different subunits with a total molecular mass of 350 kDa for a monomer. It catalyses light-driven water oxidation at its catalytic centre, the oxygen-evolving complex (OEC). The structure of PSII has been analysed at 1.9 Å resolution by synchrotron radiation X-rays, which revealed that the OEC is a Mn4CaO5 cluster organized in an asymmetric, 'distorted-chair' form. This structure was further analysed with femtosecond X-ray free electron lasers (XFEL), providing the 'radiation damage-free' structure. The mechanism of O=O bond formation, however, remains obscure owing to the lack of intermediate-state structures. Here we describe the structural changes in PSII induced by two-flash illumination at room temperature at a resolution of 2.35 Å using time-resolved serial femtosecond crystallography with an XFEL provided by the SPring-8 ångström compact free-electron laser. An isomorphous difference Fourier map between the two-flash and dark-adapted states revealed two areas of apparent changes: around the QB/non-haem iron and the Mn4CaO5 cluster. The changes around the QB/non-haem iron region reflected the electron and proton transfers induced by the two-flash illumination. In the region around the OEC, a water molecule located 3.5 Å from the Mn4CaO5 cluster disappeared from the map upon two-flash illumination. This reduced the distance between another water molecule and the oxygen atom O4, suggesting that proton transfer also occurred. Importantly, the two-flash-minus-dark isomorphous difference Fourier map showed an apparent positive peak around O5, a unique μ4-oxo-bridge located in the quasi-centre of Mn1 and Mn4 (refs 4,5). This suggests the insertion of a new oxygen atom (O6) close to O5, providing an O=O distance of 1.5 Å between these two oxygen atoms. This provides a mechanism for the O=O bond formation consistent with that proposed previousl