Study of selected iron chelators for oxidative stress prevention in PC12 cell line

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Pavel Homola Supervisor: doc. PharmDr. Tomáš Šimůnek, Ph.D. Title of diploma thesis: Study of selected iron chelators for oxidative stress prevention in PC12 cell line Parkinson's disease is a progressive neurodegenerative disease with motoric symptoms (tremor, rigidity, akinesia, postural disorders), which are connected with the loss of dopaminergic neurons in Substantia nigra pars compacta. Oxidative stress has been associated with patological processes of PD as an initiator or a member of patological cascades. Morover, oxidative stress plays a role in development of several diseases, e.g. cardiovascular disorders. Damages caused by oxidative stress are based on reactive oxidative species (ROS). The most common and the most toxic compound is hydroxyl radical, which is created by chemical reaction with iron as a catalyst (Fenton reaction). Iron chelators act as protectors against oxidative harm in tissues. They chelate iron ions, therefore prevent their catalytic activity and formation of ROS. This study deals with the determination of cytotoxicity and protective effects of clinically used iron chelators (deferoxamine - DFO, deferiprone - L1, deferasirox - ICL670A) in PC12 cell line as...Univerzita Karlova v Praze Farmaceutická fakulta v Hradci Králové Katedra biochemických věd Kandidát: Pavel Homola Školitel: doc. PharmDr. Tomáš Šimůnek, Ph.D. Název diplomové práce: Studium vybraných chelátorů železa pro prevenci oxidačního stresu u buněčné linie PC12 Parkinsonova nemoc (PD) je progresivní neurodegenerativní chorobou s motorickými symptomy (třes, rigidita, akineze, posturální poruchy), které jsou spojeny s úbytkem dopaminergních neuronů v Substatia nigra pars compacta. S patologickými procesy nemoci je silně spojen oxidační stres, který je iniciátorem či součinitelem patologických kaskád. Oxidační stres má vliv i na řadu jiných onemocnění (např. kardiovaskulární nemoci). Jeho základem je působení reaktivních sloučenin kyslíku (ROS). Nejběžnější a nejtoxičtější sloučeninou je hydroxylový radikál, který vzniká nejčastěji reakcemi katalyzovanými volnými ionty železa (Fentonova reakce). Protektivně působí proti oxidačnímu poškození tkání chelátory železa, které chelatací iontů brání jejich katalytickému působení. Předložená práce se zabývá stanovením toxicity a protektivních účinků klinicky používaných chelátorů železa (deferoxamin - DFO, deferipron - L1 a deferasirox - ICL670A) in vitro na buněčné linii PC12, která zde slouží jako model dopaminergních neuronů a PD, s použitím...Katedra biochemických vědDepartment of Biochemical SciencesFarmaceutická fakulta v Hradci KrálovéFaculty of Pharmacy in Hradec Králov

Structure and replication cycle of a virus infecting climate-modulating algaEmiliania huxleyi

The globally distributed marine alga Emiliania huxleyi produces reflective calcite disks (coccoliths) that increase the albedo of ocean water and thus reduce the heat absorption in the ocean, which cools the Earth’s climate. The population density of E. huxleyi is restricted by nucleocytoplasmic large DNA viruses, including E. huxleyi virus 201 (EhV-201). Despite the impact of E. huxleyi viruses on the climate, there is limited information about their structure and replication. Here we show that the dsDNA genome inside the EhV-201 virion is protected by an inner membrane, capsid, and outer membrane decorated with numerous transmembrane proteins. The virions are prone to deformation, and parts of their capsids deviate from the icosahedral arrangement. EhV-201 virions infect E. huxleyi by using their fivefold vertex to bind to a host cell and fuse the virus’s inner membrane with the plasma membrane. Whereas the replication of EhV-201 probably occurs in the nucleus, virions assemble in the cytoplasm at the surface of endoplasmic reticulum-derived membrane segments. Genome packaging initiates synchronously with the capsid assembly and completes through an aperture in the forming capsid. Upon the completion of genome packaging, the capsids change conformation, which enables them to acquire an outer membrane by budding into intracellular vesicles. EhV-201 infection induces a loss of surface protective layers from E. huxleyi cells, which allows the continuous release of virions by exocytosis. Our results provide insight into how EhVs bypass the surface protective layers of E. huxleyi and exploit the organelles of an infected cell for progeny assembly

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Multiple Scenario Generation of Subsurface Models:Consistent Integration of Information from Geophysical and Geological Data throuh Combination of Probabilistic Inverse Problem Theory and Geostatistics

Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming \u3c4 neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in 3c 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an E\u3bd-2 spectrum in the energy range 1.0 7 1017 eV -2.5 7 1019 eV is E2 dN\u3bd/dE\u3bd < 4.4 7 10-9 GeV cm-2 s-1 sr-1, placing strong constraints on several models of neutrino production at EeV energies and on the properties of the sources of ultra-high-energy cosmic rays

Study of selected iron chelators for oxidative stress prevention in PC12 cell line

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Pavel Homola Supervisor: doc. PharmDr. Tomáš Šimůnek, Ph.D. Title of diploma thesis: Study of selected iron chelators for oxidative stress prevention in PC12 cell line Parkinson's disease is a progressive neurodegenerative disease with motoric symptoms (tremor, rigidity, akinesia, postural disorders), which are connected with the loss of dopaminergic neurons in Substantia nigra pars compacta. Oxidative stress has been associated with patological processes of PD as an initiator or a member of patological cascades. Morover, oxidative stress plays a role in development of several diseases, e.g. cardiovascular disorders. Damages caused by oxidative stress are based on reactive oxidative species (ROS). The most common and the most toxic compound is hydroxyl radical, which is created by chemical reaction with iron as a catalyst (Fenton reaction). Iron chelators act as protectors against oxidative harm in tissues. They chelate iron ions, therefore prevent their catalytic activity and formation of ROS. This study deals with the determination of cytotoxicity and protective effects of clinically used iron chelators (deferoxamine - DFO, deferiprone - L1, deferasirox - ICL670A) in PC12 cell line as..