21 research outputs found
Kis molekulák adatbázis alapú teljes spektroszkópiája = Database approach to the complete spectroscopy of small molecules
A Jonathan Tennyson professzorral (UCL, London, UK) csoportjával kezdeményezett kutatási együttműködés a számítógépes nagyfelbontású molekulaspektroszkópia területén valósult meg. A közös kutatómunka négy publikációt eredményezett, mindegyik a víz spektroszkópiájára vonatkozott, mely a legfontosabb földi üvegház hatású gáz. Az együttműködés keretében minden eddiginél pontosabb ab initio szemiglobális potenciális energia (PES) és dipólusmomentum (DMS) felületeket készítettünk a víz molekula elektron alapállapotára. Az azóta már többek által felhasznált PES neve CVRQD, míg a DMS-é CVR, ahol CV a törzs- és vegyértékelektronok korrelált mozgásának számítására utal, míg R a relativisztikus korrekcióra. A PES számítása során kvantumelektrodinamikai (QED) és diagonális Born-Oppenheimer korrekciók (DBOC) számítására is sor került. Egy további közleményben egy minden eddiginél pontosabb PES-t közöltünk a H2(16)O, H2(17)O és H2(18)O izotopológokra, mely a kísérleti adatokhoz történt illesztésen alapult. A MARVEL (Measured Active Rotational-Vibrational Energy Levels) algoritmus elkészítésében is közreműködött Tennyson professzor. | The research collaboration proposed with the group of Professor Jonathan Tennyson (UCL, London, UK) concerned the area of computational high-resolution molecular spectroscopy. The joint research resulted in four publications, all related to the spectroscopy of the water molecule, the most important greenhouse gas on Earth. Within the collaboration we developed ab initio semiglobal potential energy (PES) and dipole moment (DMS) surfaces of unprecedented accuracy for the ground electronic state of the water molecule. These PES and DMS surfaces, which have been used by many others since their development, are called CVRQD and CVR, respectively, where CV refers to the correlated motion electronic structure computations involving core and valence electrons, while R stand for the inclusion of relativistic effects. During the computation of the PES we considered quantum electrodynamic (QED) and diagonal Born-Oppenheimer (DBOC) effects, as well. In another publication we presented theup to now most accurate empirical PES for the isotopologues H2(16)O, H2(17)O, and H2(18)O, whose development was based on a refinement to existing observed data. Development of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure was also performed in collaboration with Professor Tennyson
Újítsuk meg az iskolát! Nyílt kurzus tervezése és indítása a közoktatásban
A Pannon Egyetem MFTK Digitális Módszertani Intézet Online képzések és a nyílt oktatás pedagógiája (VETKPPT322P) tantárgy keretében háromfős csapatunk feladata egy nyílt kurzus megtervezése, meghirdetése és megtartása volt a közoktatásban tanulók számára. Ennek témájául a diákönkormányzatok érdekképviseleti tevékenységét választottuk, melynek keretében a gimnáziumi tananyagban szereplő érvelés, szónoki beszéd témakörét érintettük egy tantárgyaktól független helyzetben. A gyakorlati tartalmat pedig a digitális munkarendben megismert jó gyakorlatokra szűkítettük. A háromhetes kurzust Google Osztályteremben valósítottuk meg két résztvevővel május 10. és június 2. között. = Within the course of Online Trainings and Pedagogy of Open Education (VETKPPT322P) by the Pannon Univer-sity MFTK Digital Methodology Institute, the task of our three-person team was to plan, announce and hold anopen course for students in public education. We chose the advocacy activities of the student governments as thetopic of this, within which we touched upon the topic of reasoning and oratory speech of the grammar schoolcurriculum in a situation independent of the school subjects. The practical content was limited to the good practicesexperienced in the digital scheme. The three-week course was implemented in a Google Classroom with two par-ticipants from May 10th to June 2nd
Microglia protect against brain injury and their selective elimination dysregulates neuronal network activity after stroke
Microglia are the main immune cells of the brain and contribute to common brain diseases. However, it is unclear how microglia influence neuronal activity and survival in the injured brain in vivo. Here we develop a precisely controlled model of brain injury induced by cerebral ischaemia combined with fast in vivo two-photon calcium imaging and selective microglial manipulation. We show that selective elimination of microglia leads to a striking, 60% increase in infarct size, which is reversed by microglial repopulation. Microglia-mediated protection includes reduction of excitotoxic injury, since an absence of microglia leads to dysregulated neuronal calcium responses, calcium overload and increased neuronal death. Furthermore, the incidence of spreading depolarization (SD) is markedly reduced in the absence of microglia. Thus, microglia are involved in changes in neuronal network activity and SD after brain injury in vivo that could have important implications for common brain diseases
Mannose-Binding Lectin Drives Platelet Inflammatory Phenotype and Vascular Damage After Cerebral Ischemia in Mice via IL (Interleukin)-1α
Objective- Circulating complement factors are activated by tissue damage and contribute to acute brain injury. The deposition of MBL (mannose-binding lectin), one of the initiators of the lectin complement pathway, on the cerebral endothelium activated by ischemia is a major pathogenic event leading to brain injury. The molecular mechanisms through which MBL influences outcome after ischemia are not understood yet. Approach and Results- Here we show that MBL-deficient (MBL-/-) mice subjected to cerebral ischemia display better flow recovery and less plasma extravasation in the brain than wild-type mice, as assessed by in vivo 2-photon microscopy. This results in reduced vascular dysfunction as shown by the shift from a pro- to an anti-inflammatory vascular phenotype associated with MBL deficiency. We also show that platelets directly bind MBL and that platelets from MBL-/- mice have reduced inflammatory phenotype as indicated by reduced IL-1α (interleukin-1α) content, as early as 6 hours after ischemia. Cultured human brain endothelial cells subjected to oxygen-glucose deprivation and exposed to platelets from MBL-/- mice present less cell death and lower CXCL1 (chemokine [C-X-C motif] ligand 1) release (downstream to IL-1α) than those exposed to wild-type platelets. In turn, MBL deposition on ischemic vessels significantly decreases after ischemia in mice treated with IL-1 receptor antagonist compared with controls, indicating a reciprocal interplay between MBL and IL-1α facilitating endothelial damage. Conclusions- We propose MBL as a hub of pathogenic vascular events. It acts as an early trigger of platelet IL-1α release, which in turn favors MBL deposition on ischemic vessels promoting an endothelial pro-inflammatory phenotype
Microglia modulate blood flow, neurovascular coupling, and hypoperfusion via purinergic actions
Microglia, the main immunocompetent cells of the brain, regulate neuronal function, but their contribution to cerebral blood flow (CBF) regulation has remained elusive. Here, we identify microglia as important modulators of CBF both under physiological conditions and during hypoperfusion. Microglia establish direct, dynamic purinergic contacts with cells in the neurovascular unit that shape CBF in both mice and humans. Surprisingly, the absence of microglia or blockade of microglial P2Y12 receptor (P2Y12R) substantially impairs neurovascular coupling in mice, which is reiterated by chemogenetically induced microglial dysfunction associated with impaired ATP sensitivity. Hypercapnia induces rapid microglial calcium changes, P2Y12R-mediated formation of perivascular phylopodia, and microglial adenosine production, while depletion of microglia reduces brain pH and impairs hypercapnia-induced vasodilation. Microglial actions modulate vascular cyclic GMP levels but are partially independent of nitric oxide. Finally, microglial dysfunction markedly impairs P2Y12R-mediated cerebrovascular adaptation to common carotid artery occlusion resulting in hypoperfusion. Thus, our data reveal a previously unrecognized role for microglia in CBF regulation, with broad implications for common neurological diseases
Inherently fluorescent and porous zirconia colloids : preparation, characterization and drug adsorption studies
Porous, fluorescent zirconia particles of nearly 380 nm diameter were prepared without template molecules
or labeling dyes. The porous structure is the result of aggregation-induced particle formation. The inherent
fluorescence is assigned to coordinatively unsaturated Zr4+ ions at the sol–gel derived ZrO2 surface. After
physico-chemical characterization of the native zirconia particles carboxyl and/or amine bearing drug molecules
(D,L-a-difluoromethylornithine – DFMO, ursolic acid – UA and doxorubicin – DOX) were adsorbed
onto their surface, and the products were analyzed with Fourier-transform infrared spectroscopy (FTIR),
thermogravimetry (TG), small-angle X-ray scattering (SAXS), fluorimetry and zeta potential vs. pH measurements.
We have found that DOX complexes coordinatively unsaturated Zr4+ ions without dislocating them,
while carboxyl-bearing drugs interact with basic surface Zr–OH sites eliminating some of the carbonate
species. The adsorption of UA at the zirconia surface shifts considerably the isoelectric point of the surface
and thus provides kinetic stability to the particles at physiological pH. An in vivo biodistribution study in
two healthy dogs performed by SPECT/CT detection after 99mTc labeling of the nanocarriers has shown
the possibility of drug delivery application
Interleukin-1 mediates ischaemic brain injury via distinct actions on endothelial cells and cholinergic neurons.
The cytokine interleukin-1 (IL-1) is a key contributor to neuroinflammation and brain injury, yet mechanisms by which IL-1 triggers neuronal injury remain unknown. Here we induced conditional deletion of IL-1R1 in brain endothelial cells, neurons and blood cells to assess site-specific IL-1 actions in a model of cerebral ischaemia in mice. Tamoxifen treatment of IL-1R1 floxed (fl/fl) mice crossed with mice expressing tamoxifen-inducible Cre-recombinase under the Slco1c1 promoter resulted in brain endothelium-specific deletion of IL-1R1 and a significant decrease in infarct size (29%), blood-brain barrier (BBB) breakdown (53%) and neurological deficit (40%) compared to vehicle-treated or control (IL-1R1fl/fl) mice. Absence of brain endothelial IL-1 signalling improved cerebral blood flow, followed by reduced neutrophil infiltration and vascular activation 24 h after brain injury. Conditional IL-1R1 deletion in neurons using tamoxifen inducible nestin-Cre mice resulted in reduced neuronal injury (25%) and altered microglia-neuron interactions, without affecting cerebral perfusion or vascular activation. Deletion of IL-1R1 specifically in cholinergic neurons reduced infarct size, brain oedema and improved functional outcome. Ubiquitous deletion of IL-1R1 had no effect on brain injury, suggesting beneficial compensatory mechanisms on other cells against the detrimental effects of IL-1 on endothelial cells and neurons. We also show that IL-1R1 signalling deletion in platelets or myeloid cells does not contribute to brain injury after experimental stroke. Thus, brain endothelial and neuronal (cholinergic) IL-1R1 mediate detrimental actions of IL-1 in the brain in ischaemic stroke. Cell-specific targeting of IL-1R1 in the brain could therefore have therapeutic benefits in stroke and other cerebrovascular diseases
Several proteins form variable RNA editing complexes in plant organelles
In RNA editing in plant organelles, PPR (Pentatricopeptide Repeat) proteins with an E or E and DYW domains at the C-terminus are important participants for recognizing the specific cis-elements. These proteins are able to connect to their target RNA sequence via the PPR domains. Recognition of the specific target RNA sequence by PPR proteins is based on the specific binding of one PPR motif to one nucleotide.
There are several possibilities for the function of the E-domains in the PPR RNA editing factors: they may bind to the RNA as well as the PPR motifs, or provide the interacting surface for other proteins involved also in the RNA editing process. It is also not excluded that E domains perform these two possible tasks simultaneously. The DYW domain contains a conserved motif (HxExnCxxC) of cytidine deaminases and shows zinc-binding capability, suggesting the domain works as the so far missing deaminase enzyme. But its cytidine deaminase activity has not yet been proofed.
The MORFs (Multiple Organellar RNA Editing Factors) also termed as RIPs (RNA editing factor Interacting Proteins) are also involved in several C-to-U substitution events in flowering plants mitochondria and/or in chloroplasts. Nine members of this family contain the conserved 100 amino acids long MORF box and one protein contains only the C-terminally half of that. The exact function of these proteins is unknown yet, but it is suggested that they work together with PPR proteins to perform certain RNA editing events maybe through their direct connections to PPR proteins at each MORF box.
To understand further detailed functions of the three domains PPR, E and DYW in RNA editing factors, I employed three different approaches. The first one is functional complementation of the mef28-1 RNA editing mutants with chimeric PPR type RNA editing factors. The MEF28 is involved in the editing of two neighboring cytidines at the nad2-89 and 90 sites. We are interested in how this rarely event is performed by a single PPR protein. The DYW domain of MEF28 is not able to substitute to other DYW domains to edit the downstream cytidine in the two nad2 sites, suggesting its requirement for the flexible targeting function. In the second approach I used Y2H analyses for mapping the binding sites between MEFs (Mitochondrial RNA Editing Factors) and MORFs. In the most cases the bait wild type and partial MEF proteins could connect to the MORF1, MORF2, MORF8 and MORF9, rarely with MORF3 and very rarely with MORF4, MORF5, MORF6 and MORF7. In contrast, the wild type and the partial MEF8 bait constructs (except the MEF8_ECE+) could bind to almost all MORF preys, indicates that MEF8 is a very unique PPR protein. After Y2H analyses of several different partial E domain constructs, I found that the MEF21 is able to bind with the MORF1 through the N-terminal part of the E domain. Finally, I established the Pichia pastoris expression system to express recombinant PPR type RNA editing proteins. The system is now available for further molecular functional analysis of PPR proteins that have been difficult to be expressed in E.coli system
The DYW Subgroup PPR Protein MEF35 Targets RNA Editing Sites in the Mitochondrial rpl16, nad4 and cob mRNAs in Arabidopsis thaliana.
RNA editing in plant mitochondria and plastids alters specific nucleotides from cytidine (C) to uridine (U) mostly in mRNAs. A number of PLS-class PPR proteins have been characterized as RNA recognition factors for specific RNA editing sites, all containing a C-terminal extension, the E domain, and some an additional DYW domain, named after the characteristic C-terminal amino acid triplet of this domain. Presently the recognition factors for more than 300 mitochondrial editing sites are still unidentified. In order to characterize these missing factors, the recently proposed computational prediction tool could be of use to assign target RNA editing sites to PPR proteins of yet unknown function. Using this target prediction approach we identified the nuclear gene MEF35 (Mitochondrial Editing Factor 35) to be required for RNA editing at three sites in mitochondria of Arabidopsis thaliana. The MEF35 protein contains eleven PPR repeats and E and DYW extensions at the C-terminus. Two T-DNA insertion mutants, one inserted just upstream and the other inside the reading frame encoding the DYW domain, show loss of editing at a site in each of the mRNAs for protein 16 in the large ribosomal subunit (site rpl16-209), for cytochrome b (cob-286) and for subunit 4 of complex I (nad4-1373), respectively. Editing is restored upon introduction of the wild type MEF35 gene in the reading frame mutant. The MEF35 protein interacts in Y2H assays with the mitochondrial MORF1 and MORF8 proteins, mutation of the latter also influences editing at two of the three MEF35 target sites. Homozygous mutant plants develop indistinguishably from wild type plants, although the RPL16 and COB/CYTB proteins are essential and the amino acids encoded after the editing events are conserved in most plant species. These results demonstrate the feasibility of the computational target prediction to screen for target RNA editing sites of E domain containing PLS-class PPR proteins
Korrekciós tréning hatékonyságvizsgálata a NEKA u16-os női kézilabdacsapatnál
Ahogy minden sportoló, a kézilabdázók fejlesztése is többlépcsős, multidiszciplináris feladat. A kutatás célja egy alapozó, felkészítő korrekciós tréningprogram hatékonyság-vizsgálata a Nemzeti Kézilabda Akadémia első évfolyamos női sportolóinál a további fokozódó terhelhetőség, illetve a sérülések gyakoriságának csökkentése érdekében