Metal ions play a crucial role in enzymatic reactions in all photosynthetic organisms such as cyanobacteria, algae and plants. It well known that metal ions maintain the binding of substrate in the active site of the metalloenzymes and control the redox activity of the metalloenzyme in the enzymatic reaction. A large pigment-protein complex, PSII, known to serve as a water-plastoquinone oxidoreductase, contains three metal centers comprising non-heme iron, heme iron of Cyt b559 and the water-splitting manganese complex. Metal ions bound to PSII proteins maintain the electron transport from water to plastoquinone and regulate the pro-oxidant and antioxidant activity in PSII. In this review, attention is focused on the role of PSII metal centers in (i) the formation of superoxide anion and hydroxyl radicals by sequential one-electron reduction of molecular oxygen and the formation of hydrogen peroxide by incomplete two-electron oxidation of water; and (ii) the elimination of superoxide anion radical by one-electron oxidation and reduction (superoxide dismutase activity) and of hydrogen peroxide by two-electron oxidation and reduction (catalase activity). The balance between the formation and elimination of reactive oxygen species by PSII metal centers is discussed as an important aspect in the prevention of photo-oxidative damage of PSII proteins and lipids.

• MeSH
• cytochromy typu b chemie   metabolismus   MeSH
• fotosystém II (proteinový komplex) chemie   metabolismus   MeSH
• katalytická doména MeSH
• kovy metabolismus   MeSH
• kyslík metabolismus   MeSH
• mangan metabolismus   MeSH
• molekulární modely MeSH
• oxidace-redukce MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rostliny enzymologie   MeSH
• scavengery volných radikálů metabolismus   MeSH
• sinice enzymologie   MeSH
• voda metabolismus   MeSH
• železo metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

• MeSH
• antiflogistika nesteroidní farmakologie   MeSH
• cytochromy c metabolismus   MeSH
• epitel fyziologie   MeSH
• kyselina arachidonová metabolismus   MeSH
• lidé MeSH
• morčata MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• svalový tonus účinky léků   MeSH
• techniky in vitro MeSH
• trachea fyziologie   MeSH
• Check Tag
• lidé MeSH
• morčata MeSH

The purpose of the present study was to assess the effect of different water immersion temperatures on handgrip performance and haemodynamic changes in the forearm flexors of males and females. Twenty-nine rock-climbers performed three repeated intermittent handgrip contractions to failure with 20 min recovery on three separate laboratory visits. For each visit, a randomly assigned recovery strategy was applied: cold water immersion (CWI) at 8 °C (CW8), 15 °C (CW15) or passive recovery (PAS). While handgrip performance significantly decreased in the subsequent trials for the PAS (p < 0.05), there was a significant increase in time to failure for the second and third trial for CW15 and in the second trial for CW8; males having greater performance improvement (44%) after CW15 than females (26%). The results indicate that CW15 was a more tolerable and effective recovery strategy than CW8 and the same CWI protocol may lead to different recovery in males and females.

• MeSH
• cvičení fyziologie   MeSH
• dospělí MeSH
• kryoterapie metody   MeSH
• kyslík fyziologie   MeSH
• lidé MeSH
• nízká teplota škodlivé účinky   MeSH
• ponoření MeSH
• sexuální faktory MeSH
• síla ruky fyziologie   MeSH
• svalová kontrakce fyziologie   MeSH
• voda MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH

• MeSH
• acetylcystein farmakologie   MeSH
• antioxidancia farmakologie   MeSH
• aorta metabolismus   účinky léků   MeSH
• cyklické N-oxidy farmakologie   MeSH
• finanční podpora výzkumu jako téma MeSH
• hypertenze chemicky indukované   metabolismus   prevence a kontrola   MeSH
• inhibitory enzymů farmakologie   MeSH
• lékové interakce MeSH
• NG-nitroargininmethylester farmakologie   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• synthasa oxidu dusnatého antagonisté a inhibitory   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH

We report a case of a 20-year-old male patient suffering from motorcycle accident complicated by rapid development of severe refractory hypoxemia and hypercapnia due to serious bilateral lung contusions and lacerations. Positive pressure mechanical ventilation induced pressure-dependent massive air leak from disrupted pulmonary tissue. Simultaneous implementation of veno-venous extracorporeal membrane oxygenation together with surfactant application allowed prolonged disconnection of patient from mechanical ventilation ("total lung rest" mode). Despite considerable areas of nonaerated tissue on computed tomography prior to the disconnection from mechanical ventilation, almost total functional recovery of lungs was eventually achieved.

• MeSH
• hypoxie diagnostické zobrazování   patofyziologie   terapie   MeSH
• lidé MeSH
• mimotělní membránová oxygenace metody   MeSH
• mladý dospělý MeSH
• plíce diagnostické zobrazování   patofyziologie   MeSH
• počítačová rentgenová tomografie MeSH
• povrchově aktivní látky terapeutické užití   MeSH
• syndrom dechové tísně diagnostické zobrazování   patofyziologie   terapie   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Abiotic stress poses constant challenges for plant survival and is a serious problem for global agricultural productivity. On a molecular level, stress conditions result in elevation of reactive oxygen species (ROS) production causing oxidative stress associated with oxidation of proteins and nucleic acids as well as impairment of membrane functions. Adaptation of root growth to ROS accumulation is facilitated through modification of auxin and cytokinin hormone homeostasis. Here, we report that in Arabidopsis root meristem, ROS-induced changes of auxin levels correspond to decreased abundance of PIN auxin efflux carriers at the plasma membrane (PM). Specifically, increase in H2O2 levels affects PIN2 endocytic recycling. We show that the PIN2 intracellular trafficking during adaptation to oxidative stress requires the function of the ADP-ribosylation factor (ARF)-guanine-nucleotide exchange factor (GEF) BEN1, an actin-associated regulator of the trafficking from the PM to early endosomes and, presumably, indirectly, trafficking to the vacuoles. We propose that H2O2 levels affect the actin dynamics thus modulating ARF-GEF-dependent trafficking of PIN2. This mechanism provides a way how root growth acclimates to stress and adapts to a changing environment.

• MeSH
• ADP-ribosylační faktory metabolismus   fyziologie   MeSH
• aktiny metabolismus   MeSH
• alkoholoxidoreduktasy metabolismus   fyziologie   MeSH
• Arabidopsis metabolismus   fyziologie   MeSH
• cytoskelet metabolismus   MeSH
• fyziologická adaptace MeSH
• kořeny rostlin metabolismus   fyziologie   MeSH
• oxidační stres * MeSH
• peroxid vodíku metabolismus   MeSH
• proteiny huseníčku metabolismus   fyziologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• výměnné faktory guaninnukleotidů metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• amositový azbest toxicita   MeSH
• analýza rozptylu MeSH
• antioxidancia metabolismus   MeSH
• azbestóza MeSH
• krysa rodu rattus MeSH
• plíce cytologie   chemie   účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• srovnávací studie MeSH

Although the PSII complex is highly conserved in cyanobacteria and chloroplasts, the PsbU and PsbV subunits stabilizing the oxygen-evolving Mn4CaO5 cluster in cyanobacteria are absent in chloroplasts and have been replaced by the PsbP and PsbQ subunits. There is, however, a distant cyanobacterial homolog of PsbP, termed CyanoP, of unknown function. Here we show that CyanoP plays a role in the early stages of PSII biogenesis in Synechocystis sp. PCC 6803. CyanoP is present in the PSII reaction center assembly complex (RCII) lacking both the CP47 and CP43 modules and binds to the smaller D2 module. A small amount of larger PSII core complexes co-purifying with FLAG-tagged CyanoP indicates that CyanoP can accompany PSII on most of its assembly pathway. A role in biogenesis is supported by the accumulation of unassembled D1 precursor and impaired formation of RCII in a mutant lacking CyanoP. Interestingly, the pull-down preparations of CyanoP-FLAG from a strain lacking CP47 also contained PsbO, indicating engagement of this protein with PSII at a much earlier stage in assembly than previously assumed.

• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• mutace MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• Synechocystis genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Thylakoid biogenesis is an intricate process requiring accurate and timely assembly of proteins, pigments and other cofactors into functional, photosynthetically competent membranes. PSII assembly is studied in particular as its core protein, D1, is very susceptible to photodamage and has a high turnover rate, particularly in high light. PSII assembly is a modular process, with assembly steps proceeding in a specific order. Using aqueous two-phase partitioning to separate plasma membranes (PM) and thylakoid membranes (TM), we studied the subcellular localization of the early assembly steps for PSII biogenesis in a Synechocystis sp. PCC6803 cyanobacterium strain lacking the CP47 antenna. This strain accumulates the early D1-D2 assembly complex which was localized in TM along with associated PSII assembly factors. We also followed insertion and processing of the D1 precursor (pD1) by radioactive pulse-chase labeling. D1 is inserted into the membrane with a C-terminal extension which requires cleavage by a specific protease, the C-terminal processing protease (CtpA), to allow subsequent assembly of the oxygen-evolving complex. pD1 insertion as well as its conversion to mature D1 under various light conditions was seen only in the TM. Epitope-tagged CtpA was also localized in the same membrane, providing further support for the thylakoid location of pD1 processing. However, Vipp1 and PratA, two proteins suggested to be part of the so-called 'thylakoid centers', were found to associate with the PM. Together, these results suggest that early PSII assembly steps occur in TM or specific areas derived from them, with interaction with PM needed for efficient PSII and thylakoid biogenesis.

• MeSH
• bakteriální proteiny metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• fotosyntéza účinky záření   MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• světlo MeSH
• Synechocystis metabolismus   účinky záření   MeSH
• tylakoidy metabolismus   účinky záření   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The β-adrenergic signaling pathways and antioxidant defence mechanisms play important roles in maintaining proper heart function. Here, we examined the effect of chronic normobaric hypoxia (CNH, 10% O2, 3 weeks) on myocardial β-adrenergic signaling and selected components of the antioxidant system in spontaneously hypertensive rats (SHR) and in a conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR with that of the more ischemia-resistant Brown Norway strain. Our investigations revealed some intriguing differences between the two strains at the level of β-adrenergic receptors (β-ARs), activity of adenylyl cyclase (AC) and monoamine oxidase A (MAO-A), as well as distinct changes after CNH exposure. The β2-AR/β1-AR ratio was significantly higher in SHR-mtBN than in SHR, apparently due to increased expression of β2-ARs. Adaptation to hypoxia elevated β2-ARs in SHR and decreased the total number of β-ARs in SHR-mtBN. In parallel, the ability of isoprenaline to stimulate AC activity was found to be higher in SHR-mtBN than that in SHR. Interestingly, the activity of MAO-A was notably lower in SHR-mtBN than in SHR, and it was markedly elevated in both strains after exposure to hypoxia. In addition to that, CNH markedly enhanced the expression of catalase and aldehyde dehydrogenase-2 in both strains, and decreased the expression of Cu/Zn superoxide dismutase in SHR. Adaptation to CNH intensified oxidative stress to a similar extent in both strains and elevated the IL-10/TNF-α ratio in SHR-mtBN only. These data indicate that alterations in the mitochondrial genome can result in peculiar changes in myocardial β-adrenergic signaling, MAO-A activity and antioxidant defence and may, thus, affect the adaptive responses to hypoxia.

• MeSH
• adenylátcyklasy metabolismus   MeSH
• beta-adrenergní receptory metabolismus   MeSH
• hypoxie metabolismus   MeSH
• krysa rodu rattus MeSH
• malondialdehyd metabolismus   MeSH
• monoaminoxidasa metabolismus   MeSH
• myokard metabolismus   MeSH
• potkani inbrední SHR MeSH
• signální transdukce fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH