The function of chloroplast ferredoxin quinone reductase (FQR)-dependent flow was examined by comparing a wild type tobacco and a tobacco transformant (ΔndhB) in which the ndhB gene had been disrupted with their antimycin A (AA)-fed leaves upon exposure to chilling temperature (4 °C) under low irradiance (100 µmol m-2 s-1 photon flux density). During the chilling stress, the maximum photochemical efficiency of photosystem (PS) 2 (Fv/Fm) decreased markedly in both the controls and AA-fed leaves, and P700+ was also lower in AA-fed leaves than in the controls, implying that FQR-dependent cyclic electron flow around PS1 functioned to protect the photosynthetic apparatus from chilling stress under low irradiance. Under such stress, non-photochemical quenching (NPQ), particularly the fast relaxing NPQ component (qf) and the de-epoxidized ratio of the xanthophyll cycle pigments, (A+Z)/(V+A+Z), formed the difference between AA-fed leaves and controls. The lower NPQ in AA-fed leaves might be related to an inefficient proton gradient across thylakoid membranes (ΔpH) because of inhibiting an FQR-dependent cyclic electron flow around PS1 at chilling temperature under low irradiance. and X.-G. Li ... [et al.].
Ferredoxin (Fd) is a small soluble iron-sulfur protein essential in almost all oxygenic photosynthetic organisms. It contains a single [2Fe-2S] cluster coordinated by four cysteine ligands. It accepts electrons from the stromal surface of PSI and facilitates transfer to a myriad of acceptors involved in diverse metabolic processes, including generation of NADPH via Fd-NADP-reductase, cyclic electron transport for ATP synthesis, nitrate reduction, nitrite reductase, sulfite reduction, hydrogenase and other reductive reactions. Fd serves as the central hub for these diverse cellular reactions and is integral to complex cellular metabolic networks. We describe advances on the central role of Fd and its evolutionary role from cyanobacteria to algae/plants. We compare structural diversity of Fd partners to understand this orchestrating role and shed light on how Fd dynamically partitions between competing partner proteins to enable the optimum transfer of PSI-derived electrons to support cell growth and metabolism., J. Mondal, B. D. Bruce., and Obsahuje bibliografické odkazy
Clear cell renal cell carcinoma (ccRCC) is very common and accounts for most kidney cancer deaths. While many studies are being conducted in finding the prognostic signatures of ccRCC, we believe that ferroptosis, which involves programmed cell death dependent on iron accumulation, has therapeutic potential in ccRCC. Recent research has shown that long noncoding RNAs (lncRNAs) are involved in ferroptosis-related tumour processes and are closely related to survival in patients with ccRCC. Hence, in this study we aim to further explore the role of ferroptosis-related lncRNAs (FRLs) in ccRCC, hoping to establish a signature to predict the survival outcome of ccRCC. We analysed transcriptome data from The Cancer Genome Atlas database (TCGA) and ferroptosis-related genes (FRGs) from FerrDb to identify FRLs using Pearson’s correlation. Lasso Cox regression analysis and multivariate Cox proportional hazards models screened seventeen optimal FRLs for developing prognostic signatures. Kaplan-Meier survival curves and ROC curves were then plotted for validating the sensitivity, specificity, and accuracy of the identified signatures. Gene Set Enrichment Analysis and CIBERSORT algorithm were deployed to explore the role of these FRLs in the tumour microenvironment. It was concluded that these models demonstrate excellent performance in predicting prognosis among patients with ccRCC, also indicating association with the clinicopathologic parameters such as tumour grade, tumour stage and tumour immune infiltration. In conclusion, our findings provide novel insights into ferroptosis-related lncRNAs in ccRCC, which are important targets for investigating the tumorigenesis of ccRCC.
We examined the effects of foliar application of various nitrogen (urea) concentrations on gas-exchange and chlorophyll (Chl) fluorescence characteristics in bean plants treated by heat stress (42/30°C, day/night temperatures). Heat stress caused reductions in contents of Chl a, Chl b, and in maximum photochemical efficiency of PSII by 13, 20, and 27%, respectively, regardless of the N treatment. However, N fertilization caused significant increases in these parameters, especially at higher N concentrations. The net photosynthetic rate and stomatal conductance were enhanced by 32, 60, and 69% and by 25, 88, and 100% due to addition of 5, 10, and 15 mM N, respectively. However, gas-exchange parameters were reduced by 24% due to heat stress. N fertilization alleviated adverse effects of heat stress., I. A. Hassan, H. M. Abou Zeid, W. Taia, N. S. Haiba, A. Zahran, R. H. Badr, R. A. El Dakak, E. A. Shalaby., and Obsahuje bibliografii
Optical fiber sensors can bring many advantages to biological, medical or environmental applications. They offer small size, immunity to electro-magnetic field and limited unwanted interaction with measured sample. One of the key parameters monitored in biological systems is the acidity of environment expressed as pH. The article deals with development of an optical pH-sensor with tapered fiber probes. The principle of the sensor is based on measurement of fluorescence emission of hydroxypyrene-1,3,6-pyrene trisulfonic acid trisodium salt (HPTS, pyranine) at two different excitation wavelengths (405 nm and 450 nm). The sensor was sensitive to pH in range from 5.5 to 7.5 with resolution of ± 0.15 pH unit and the tapered fiber probes allowed in-vivo measurement in microscopic biological samples. and Optické vláknové senzory mohou přinést řadu výhod při využití v oblastech biologie, medicíny či v ochraně životního prostředí. Vyznačují se malými rozměry a odolností vůči elektromagnetickému poli, přičemž nežádoucí ovlivnění měřených vzorků je u nich též velmi omezeno. Jedním z důležitých parametrů sledovaných u biologických systémů je kyselost prostředí, vyjádřená jako pH. Článek popisuje vývoj optického pH -senzoru využívajícího zúžené vláknové sondy. Princip měření je založen na sledování emise fluorescence sodné soli kyseliny hydroxypyren-1,3,6-pyrentrisulfonové (pyranin) při excitaci dvěma odlišnými vlnovými délkami (405 nm a 450 nm). Senzor vykazoval citlivost na pH v rozsahu od 5,5 do 7,5, přičemž dosažené rozlišení činilo ±0,15 pH jednotky. Použití zúžených vláknových sond pak umožnilo in-vivo měření v mikroskopických biologických vzorcích.
Two seismic sources were tested on different surfaces during acquisition of a 5.5-km long high resolution seismic reflection (HRS) profile on the Ljubljana Moor in central Slovenia. Maximum target depth range of the survey was 200 - 300 m. Nine different combinations of source-surface conditions were analysed. Seismic sources included a seismic shotgun and an accelerated weight dropper system. The HRS profile crossed different surfaces including: paved roads, gravel roads, ploughed fields, grasslands and marshlands. Seismic source performance on different surfaces was evaluated through frequency and S/N ratio analyses of seismic data, and analysis of source-generated coherent noise appearance on seismograms. Results show that both seismic sources are suitable for some of the surfaces found in the surveyed area. The accelerated weight dropper produced the best results on gravel road surface, but poor results were found on grassland and ploughed fields. The seismic shotgun produced the best results in water-saturated soil on marshlands. It performed less favourably in unsaturated soil, generating more coherent noise. Water-saturated marshland surface and gravel road surfaces were found to be the most favourable for acquisition of high-resolution seismic reflection data on the Ljubljana Moor., Jure Atanackov and Andrej Gosar., and Obsahuje bibliografii
The paper focuses on fictional discourse, discourse about fiction and dynamic relations between them: the immediate impulse came from the recent analysis of parafictional statements proposed by François Recanati. A confrontation of basic theoretical assumptions (section I, II) will be followed by an alternative analysis: unlike Recanati’s version, it will not assume a switch to the mode of pretence as an ineliminable part of parafictional statements (III, IV). The aim will not be to replace one analysis by its rival but to show that the same sentence can be used not only to perform various functions, but also to perform the same (here: parafictional) function in various ways – and generally to demonstrate the variety of language games going on in this sphere (V). Special attention will be paid to their specific dynamics, including the fluctuation between the “serious” and fictional modes of speech (VI). and Hlavním tématem článku je povaha fikčního diskursu, diskursu o fikci a dynamické vztahy mezi nimi; bezprostřední výzvou, na niž text reaguje, je ale Recanatiho analýza parafikčních výpovědí (tvrzení typu „Ve Flaubertově románu je Ema mladá, senzitivní a poněkud lehkovážná žena“). Po vymezení hlavních rozdílů a shod v našem chápání role fikčních jmen v narativní fikci, vztahu mezi jejich referenty (předpokládanými v modu jako by) a fikčními postavami, úlohy předstírání atd. (kap. I, II) navrhnu ke zvážení alternativní analýzu: od Recanatiho verze se bude lišit tím, že nepředpokládá přechod do modu předstírání („pretence“, „make-believe“) jako neeliminovatelnou součást parafikčních tvrzení (kap. III, IV). Nepůjde přitom o to postavit proti sobě dvě konkurenční analýzy, ale ukázat, že tatáž věta může nejen plnit různé funkce, ale i plnit tutéž (např. parafikční) funkci různými způsoby – a obecně demonstrovat rozmanitost jazykových her probíhajících v této sféře (kap. V). Zaměříme se i na jejich specifickou dynamiku; zejména na případy, kdy vývoj komunikace převádí parafikční výpovědi (vykonávané v modu „seriózních“ tvrzení) se zpětnou platností do modu fikce, v zájmu zachování kontinuity konverzace nebo jejího obnovení na nové bázi (kap. VI). Poslouží nám jako příklady dynamických přechodů mezi fikčním a ne- -fikčním režimem řeči a jako doklad faktu, že status našich výpovědí může být nejen potvrzen („ratifikován“), ale i revidován v průběhu komunikace. Závěrečná série komentovaných příkladů (kap. VII) se zaměří na případy (intertextově založené parafikční výpovědi), v nichž se výkony, které od mluvčího vyžaduje parafikční tvrzení v Recanatiho a autorově pojetí, radikálně liší svou náročností.