Pleiotropic Effects of Biguanides on Mitochondrial Reactive Oxygen Species Production

Metformin is widely prescribed as a first-choice antihyperglycemic drug for treatment of type 2 diabetes mellitus, and recent epidemiological studies showed its utility also in cancer therapy. Although it is in use since the 1970s, its molecular target, either for antihyperglycemic or antineoplastic action, remains elusive. However, the body of the research on metformin effect oscillates around mitochondrial metabolism, including the function of oxidative phosphorylation (OXPHOS) apparatus. In this study, we focused on direct inhibitory mechanism of biguanides (metformin and phenformin) on OXPHOS complexes and its functional impact, using the model of isolated brown adipose tissue mitochondria. We demonstrate that biguanides nonspecifically target the activities of all respiratory chain dehydrogenases (mitochondrial NADH, succinate, and glycerophosphate dehydrogenases), but only at very high concentrations (10−2–10−1 M) that highly exceed cellular concentrations observed during the treatment. In addition, these concentrations of biguanides also trigger burst of reactive oxygen species production which, in combination with pleiotropic OXPHOS inhibition, can be toxic for the organism. We conclude that the beneficial effect of biguanides should probably be associated with subtler mechanism, different from the generalized inhibition of the respiratory chain

Earthquake in the Hrubý Jeseník Mts. on 14. 6. 2012

A sequence of very weak earthquakes was recorded by local seismic stations in Hrubý Jeseník Mts. (NE part of the Czech Republic) in June and July 2012. The strongest event with local magnitude 2.3 on June 14, 2012 at 21:38 UTC was felt by people to 20 km around the epicentre with a macroseismic intensity 3–4° EMS-98. In spite of the fact that calculated focal mechanisms are still missing, the spatial extent of microearthquake epicentres suggests that the local seismicity is co-determined by the activity of the Klepáčov fault and the Sudetic Marginal – Bělá fault system.A sequence of very weak earthquakes was recorded by local seismic stations in Hrubý Jeseník Mts. (NE part of the Czech Republic) in June and July 2012. The strongest event with local magnitude 2.3 on June 14, 2012 at 21:38 UTC was felt by people to 20 km around the epicentre with a macroseismic intensity 3–4° EMS-98. In spite of the fact that calculated focal mechanisms are still missing, the spatial extent of microearthquake epicentres suggests that the local seismicity is co-determined by the activity of the Klepáčov fault and the Sudetic Marginal – Bělá fault system

Loss of COX4I1 leads to combined respiratory chain deficiency and impaired mitochondrial protein synthesis

The oxidative phosphorylation (OXPHOS) system localized in the inner mitochondrial membrane secures production of the majority of ATP in mammalian organisms. Individual OXPHOS complexes form supramolecular assemblies termed supercomplexes. The complexes are linked not only by their function but also by interdependency of individual complex biogenesis or maintenance. For instance, cytochrome c oxidase (cIV) or cytochrome bc1 complex (cIII) deficiencies affect the level of fully assembled NADH dehydrogenase (cI) in monomeric as well as supercomplex forms. It was hypothesized that cI is affected at the level of enzyme assembly as well as at the level of cI stability and maintenance. However, the true nature of interdependency between cI and cIV is not fully understood yet. We used a HEK293 cellular model where the COX4 subunit was completely knocked out, serving as an ideal system to study interdependency of cI and cIV, as early phases of cIV assembly process were disrupted. Total absence of cIV was accompanied by profound deficiency of cI, documented by decrease in the levels of cI subunits and significantly reduced amount of assembled cI. Supercomplexes assembled from cI, cIII, and cIV were missing in COX4I1 knock-out (KO) due to loss of cIV and decrease in cI amount. Pulse-chase metabolic labeling of mitochondrial DNA (mtDNA)-encoded proteins uncovered a decrease in the translation of cIV and cI subunits. Moreover, partial impairment of mitochondrial protein synthesis correlated with decreased content of mitochondrial ribosomal proteins. In addition, complexome profiling revealed accumulation of cI assembly intermediates, indicating that cI biogenesis, rather than stability, was affected. We propose that attenuation of mitochondrial protein synthesis caused by cIV deficiency represents one of the mechanisms, which may impair biogenesis of cI

Loss of COX4I1 Leads to Combined Respiratory Chain Deficiency and Impaired Mitochondrial Protein Synthesis.

Funder: Akademie Věd České Republiky; Grant(s): RVO:67985823The oxidative phosphorylation (OXPHOS) system localized in the inner mitochondrial membrane secures production of the majority of ATP in mammalian organisms. Individual OXPHOS complexes form supramolecular assemblies termed supercomplexes. The complexes are linked not only by their function but also by interdependency of individual complex biogenesis or maintenance. For instance, cytochrome c oxidase (cIV) or cytochrome bc1 complex (cIII) deficiencies affect the level of fully assembled NADH dehydrogenase (cI) in monomeric as well as supercomplex forms. It was hypothesized that cI is affected at the level of enzyme assembly as well as at the level of cI stability and maintenance. However, the true nature of interdependency between cI and cIV is not fully understood yet. We used a HEK293 cellular model where the COX4 subunit was completely knocked out, serving as an ideal system to study interdependency of cI and cIV, as early phases of cIV assembly process were disrupted. Total absence of cIV was accompanied by profound deficiency of cI, documented by decrease in the levels of cI subunits and significantly reduced amount of assembled cI. Supercomplexes assembled from cI, cIII, and cIV were missing in COX4I1 knock-out (KO) due to loss of cIV and decrease in cI amount. Pulse-chase metabolic labeling of mitochondrial DNA (mtDNA)-encoded proteins uncovered a decrease in the translation of cIV and cI subunits. Moreover, partial impairment of mitochondrial protein synthesis correlated with decreased content of mitochondrial ribosomal proteins. In addition, complexome profiling revealed accumulation of cI assembly intermediates, indicating that cI biogenesis, rather than stability, was affected. We propose that attenuation of mitochondrial protein synthesis caused by cIV deficiency represents one of the mechanisms, which may impair biogenesis of cI

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Administration, juridical, local fees and past due fees in civil law and other in the conditions of Czech Republic

Tato bakalářská práce je zaměřena na stávající právní úpravu poplatků místních, správních, soudních, z prodlení v občanském právu a ostatních v podmínkách České republiky. První část je věnována současné právní úpravě poplatků místních, soudních, správních a z prodlení v občanském právu. V závěru první části je přehled poplatků u Okresního soudu v Pardubicích za rok 2005 a 2006. Druhá část je věnována vlivu poplatků na státní rozpočet a rozpočty územně správních celků. Ve třetí části je zachycena správa daní a poplatků v působnosti Městského úřadu a Finančního úřadu v Holicích.This bachelors work is focused on current legal administration of local fees, administration fees, fees for past due in civil law and other in conditions of Czech Republic. First part is dedicated to current legal administration of local fees, administration fees, fees for past due in civil law. At the end of first part is an overview of fees at District court at Pardubice in years 2005 and 2006. Second part is dedicated to the influence of fees to govermental budget and budgets of local administrative districts. In the third part is captured administration of taxes and fees processed by Town counsel and Revenue office in Holice.Ústav veřejné správy a právaDokončená práce s úspěšnou obhajobo

SOUČASNÉ OTÁZKY DISTRIBUCE POJISTNÉ SLUŽBY V ČESKÉ REPUBLICE

Práce se zabývá analýzou distribuce pojistné služby v ČR, s akcentem na životní pojištění. Úvodní část se věnuje specifikaci pojistné služby. Hlavní část analyzuje jednotlivé distr. kanály (pojišťovna, bankopojištění, internet, telefon, makléřská společnost, samostatný zprostředkovatel, brokerpool), Multi Level Marketing. Druhá polovina je věnována rozborou osobnostních předpokladů pro činnost zprostředkovatele, typickým bodům českého finančního trhu, mým vlastním zkušenostem. Závěr práce se věnuje konkrétním návrhům pro účastníky distribuce (klient, zprostředkovatel) a státní orgány se zaměřením na dva důležité poznatky - nižší úroveň finančního povědomí občanů, obtížná srovnatelnost pojistných produktů