The photosynthetic CO2 exchange rate, chlorophyll fluorescence and P700 oxidation (absorption at 830 nm) were recorded in attached leaves of sunflower plants grown in soil by irradiance 460 pmol m'2 s‘i. Ehiring the photosynthesis in 510 cm^ m*3 CO2, 1 % O2, photosystem 1 (PS 1) effíciency was ahnost totally determined by the donor side oxidation under all irradiances. Fluorescence data showed that this control was exercised mostly by ApH-dependent plastoquinol oxidation. At 1.5 pM intracellular [CO2], the PS 1 reduction level on the acceptor side became signifícant and increased as [CO2] -> 0. ApH controlled the electron flow when the rate exceeded the value of 50 pmol(e‘) m'2 s‘i, which was close to the rate supporting photorespiration and CO2 reassimilation at CO2 compensation concentration in 21 % O2. The ApH ability to control the electron transport rate adequately prevented electron carriers reduction at PS 1 acceptor side, with stomata dosed under stress. When the low CO2 oř carbon reduction enzymes inactivation restricted the electron transport downstream of PS 1, open PS 1 centres (oxidised on acceptor sides) percentage declined in proportion to CO2 uptake rate. This makes us doubt the common belief that the rapid electron transport in photosynthesis involves interconnected, mobile electron carrier pools of plastocyanin and ferredoxin (Fd). Rather, the implications are explored in terms of supercomplexes involving cytochrome b(Jf, PC, PS 1, Fd and Fd-NADP reductase.
Acetaminophen (APAP) overdose is the most common cause of acute liver failure in humans. Non-alcoholic fatty liver disease is the most frequent chronic liver disease in developed countries. The aim of our work was to compare the effect of APAP on intact rat hepatocytes and hepatocytes isolated from steatotic liver in primary cultures. Male Wistar rats were fed with standard diet (10 % energy from fat) and high-fat diet (71 % energy from fat) for 6 weeks and then hepatocytes were isolated. After cell attachment, APAP (1; 2.5; 3.75 and 5 mM) was added to culture media (William´s E medium) and hepatocytes were cultured for up to 24 hours. APAP caused more severe dose-dependent damage of steatotic hepatocytes as documented by increased release of lactate dehydrogenase (LDH) and LDH leakage, decreased activity of cellular dehydrogenases (WST-1 test) and reduced albumin production. Intact steatotic hepatocytes contained lower amount of reduced glutathione (GSH). Treatment with APAP (1 and 2.5 mmol/l) caused more pronounced decrease in GSH in steatotic hepatocytes. ROS (reactive oxygen species) formation after 24-hour incubation was significantly higher in fatty hepatocytes using APAP at concentration of 3.75 and 5 mmol/l. Interleukin 6 (IL-6) production was elevated in 2.5 mM APAP-treated nonsteatotic and steatotic hepatocyte cultures at 8 hours, compared to appropriate controls. In conclusions, our results indicate that steatotic hepatocytes exert higher sensitivity to the toxic action of APAP. This sensitivity may be caused by lower content of GSH in intact steatotic hepatocytes and by more pronounced APAPinduced decrease in intracellular concentration of GSH., O. Kučera, ... [et al.]., and Obsahuje seznam literatury
This is a report on a post-lactating female soprano pipistrelle, Pipistrellus pygmaeus, which in autumn exploited habitats from sea level to the transition zone between alpine and sub-alpine areas. It travelled more than 12.3 kilometres from its roost and returned to its roost at sea level on all four nights when it was tracked. In addition to the telemetry bat, several soprano pipistrelles utilized high altitudes during the days of tracking as heard on ultrasound detector.