Changes in the antioxidative enzyme activities (SOD, CuZnSOD, GSH-Px, GST), as well as TBARS content in 5-week-old tomato (Lycopersicon esculentum Mill. cv ''Perkoz'') roots were examined 1, 3 h (short-term stress) and 1-14 days (long-term stress) after a single application of 50 mM (mild stress) and 150 mM NaCl (severe stress). The severe stress caused an increase in GST, GSH-Px and SODs activities from the beginning of the experiment while mild stress induced enhancement of GST activity from the second day of experiment. The maximum increase in SODs after both NaCl solutions were applied and in GST activity after the higher NaCl dose on the second day of the experiment was observed. Moreover, after 1 h of NaCl treatment with both tested NaCl solutions, the highest induction of GSH-Px activity appeared. TBARS content was elevated from the first hour of salt stress and decreased only 14 days after 50 mM NaCl application which was accompanied by high induction of GSH-Px activity. In conclusion, enhanced activities of tested enzymes indicate their involvement in early and late defence systems under salinity stress. Moreover, the dynamics of the changes in the antioxidant enzymes suggests that the second day following NaCl application is a crucial moment of the experiment with regard to saltmediated oxidative stress.

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A dinuclear iridium­(III) complex IrIr shows dual emission consisting of near infrared (NIR) phosphorescence (λmax = 714 nm, CH2Cl2, T = 300 K) and green fluorescence (λmax = 537 nm). The NIR emission stems from a triplet state (T1) localized on the ditopic bridging ligand (3LC). Because of the dinuclear molecular structure, the phosphorescence efficiency (ΦPL = 3.5%) is high compared to those of other known red/NIR-emitting iridium complexes. The weak fluorescence stems from the lowest excited singlet state (S1) of 1LC character. The occurrence of fluorescence is ascribed to relatively slow intersystem crossing (ISC) from state S1 (1LC) to the triplet manifold. The measured ISC rate corresponds to a time constant τISC of 2.1 ps, which is an order of magnitude longer than those usually found for iridium complexes. This slow ISC rate can be explained in terms of the LC character and large energy separation (0.57 eV) of the respective singlet and triplet excited states. IrIr is internalized by live HeLa cells as evidenced by confocal luminescence microscopy.

BACKGROUND Cherry fruit cracking is a costly problem for cherry growers. The effect of repeated sprayings (gibberellic acid – GA3; abscisic acid – ABA; salicylic acid – SA; glycine betaine – GB, and Ascophyllum nodosum – AN) combined with CaCl2, on ‘Sweetheart’ cherry fruit‐cracking characteristics was investigated. Cracking was quantified in terms of cracking incidence, crack morphology, confocal scanning laser microscopy, cuticular wax content, cell‐wall modification, and cuticular wax gene expression. RESULTS All spray treatments reduced cracking compared with an untreated control (H2O), with fewer cheek cracks. The least cracking incidence was observed for ABA + CaCl2‐ and GB + CaCl2‐treated fruits, indicating an added benefit compared to spraying with CaCl2 alone. In addition, GB + CaCl2‐treated fruits showed higher fruit diameter. ABA + CaCl2 and GB + CaCl2 sprays showed higher wax content and higher cuticle and epidermal thickness compared with the control, including increased expression of wax synthase (ABA + CaCl2) and expansin 1 (GB + CaCl2). CONCLUSION In general, factors that improve the cuticle thickness appear to be important at the fruit‐coloring stage. At the fruit‐ripening stage, larger cell sizes of the epidermis, hypodermis, and parenchyma cells lower cracking incidence, indicating the importance of flexibility and elasticity of the epidermis. © 2020 Society of Chemical Industry

Black spot disease, caused by Alternaria brassicicola in Brassica species, is one of the most devastating diseases all over the world, especially since there is no known fully resistant Brassica cultivar. In this study, the visualization of black spot disease development on Brassica oleracea var. capitata f. alba (white cabbage) leaves and subsequent ultrastructural, molecular and physiological investigations were conducted. Inter- and intracellular hyphae growth within leaf tissues led to the loss of host cell integrity and various levels of organelle disintegration. Severe symptoms of chloroplast damage included the degeneration of chloroplast envelope and grana, and the loss of electron denseness by stroma at the advanced stage of infection. Transcriptional profiling of infected leaves revealed that photosynthesis was the most negatively regulated biological process. However, in infected leaves, chlorophyll and carotenoid content did not decrease until 48 hpi, and several chlorophyll a fluorescence parameters, such as photosystem II quantum yield (Fv/Fm), non-photochemical quenching (NPQ), or plant vitality parameter (Rdf) decreased significantly at 24 and 48 hpi compared to control leaves. Our results indicate that the initial stages of interaction between B. oleracea and A. brassicicola are not uniform within an inoculation site and show a complexity of host responses and fungal attempts to overcome host cell defense mechanisms. The downregulation of photosynthesis at the early stage of this susceptible interaction suggests that it may be a part of a host defense strategy, or, alternatively, that chloroplasts are targets for the unknown virulence factor(s) of A. brassicicola. However, the observed decrease of photosynthetic efficiency at the later stages of infection is a result of the fungus-induced necrotic lesion expansion.

Changes in tocopherol, chlorophyll and TBARS levels and the activities of antioxidant enzymes i.e., GSH-Px, GST, and SOD in chloroplasts of tomato plants subjected to moderate (50 mM) and severe (150 mM) NaCl stress were determined. Increase in tocopherol content around the second day under both stresses did not correlate with the chlorophyll degradation while such correlation was observed from the fifth day of severe stress. The activities of GSH-Px and GST as well as TBARS content showed NaCl-induced enhancement which was dose-and time-dependent. However, chloroplastic SOD was rather not involved in the response of tomato plants to NaCl stress. The obtained results suggest that under the moderate stress similarly as in the early phase of severe stress tocopherol functions as a typical antioxidant, while in the late phase of the latter it may be involved in senescence signaling pathway and enables the recovery and recycling of the compounds significant for a plant organism.

Silver nanoparticles (AgNPs) are widely used in all branches of industry. However, their mechanisms of action towards moulds have not been studied yet. Thus we conducted this study in which we have used laser desorption/ionization time-of-flight mass spectrometry (LDI-ToF-MS) analysis to determine metabolomic changes, and microscopic analysis (transmission electron microscopy, fluorescent microscopy) to observe changes in mould cells. The AgNP treatment caused the downregulation of 162 (15 ppm) and 284 (62 ppm), and 19 (15 ppm) and 29 (62 ppm) metabolites of Aspergillus niger and Penicillium chrysogenum, respectively. All influenced features were below m/z 600 (mass-to-charge ratio). We have observed silver ions and their clusters (Ag, Ag, and Ag) accumulated in the mould mycelium. As well as, mono-silver ion adducts with nucleotide derivatives (Coenzyme A), amino acids (phenylglycine), peptides (LeuSerAlaLeuGlu) and lipids (fatty acids, diacylglycerophosphoglycerols, monoglicerides and glycerophospholipids). The ultrastructure analysis revealed many sever alterations due to the action of AgNPs, such us shortening and condensation of hyphae, ultrastructural reorganisation, cell plasmolysis, increased vacuolisation, numerous membranous structures, collapsed cytoplasm, accumulation of lipid material, condensed mitochondria, disintegration of organelles, nuclear deformation, condensation and fragmentation of chromatin, creation of apoptotic bodies, as well as a new inside cell wall in P. chrysogenum.

Large inter-individual variation in platelet response to endogenous agonists and pharmacological agents, including resistance to antiplatelet therapy, prompts a search for novel platelet inhibitors and development new antithrombotic strategies. The present in vitro study evaluates the beneficial effects of three adenosine receptor (AR) agonists (regadenoson, LUF 5835 and NECA), different in terms of their selectivity for platelet adenosine receptors, when used alone and in combination with P2Y 12 inhibitors, such as cangrelor or prasugrel metabolite. The anti-platelet effects of AR agonists were evaluated in healthy subjects (in the whole group and after stratification of individuals into high-and low-responders to P2Y 12 inhibitors), using whole blood techniques, under flow (thrombus formation) and static conditions (study of platelet activation and aggregation). Compared to P2Y 12 antagonists, AR agonists were much less or not effective under static conditions, but demonstrated similar antiplatelet activity in flow. In most cases, AR agonists significantly enhanced the anti-platelet effect of P2Y 12 antagonists, despite possessing different selectivity profiles and antiplatelet activities. Importantly, their inhibitory effects in combination with P2Y 12 antagonists were similar in high-and low-responders to P2Y 12 inhibitors. In conclusion, a combination of anti-platelet agents acting via the P1 and P2 purinergic receptors represents a promising alternative to existing antithrombotic therapy.Molecules 2020, 25, 130 2 of 17 ADP is one of the key mediators of both physiological haemostasis and thrombosis, being not only a direct agonist of platelets, but also an important factor released from platelet intracellular structures, enhancing the platelet response initially induced by other activators. Platelets have two ADP receptors on their surface: the P2Y 1 receptor initiates platelet aggregation, while the P2Y 12 receptor enhances this process, eventually leading to the formation of a clot. Due to this fact, the P2Y 12 receptor is the main therapeutic target in anti-platelet therapy targeted at the ADP-dependent activation pathway [5]. Generally, the most commonly used clinically approved P2Y 12 inhibitors include the thienopyridine-class inhibitors (ticlopidine, clopidogrel and prasugrel), the ATP analogue cangrelor, and the cyclo-pentyl-triazolo-pyrimidine derivative ticagrelor [3,5]. Thienopyridines are prodrugs: their short-lived active metabolites irreversibly inactivate the receptor and consequently inhibit ADP-induced platelet activation. Cangrelor is the first (recently approved) intravenous P2Y 12 receptor inhibitor that reversibly and non-competitively blocks ADP signalling [6].Adenosine is an important purine metabolite, serving not only as a component of nucleic acids and ATP, the most important energy carrier in the cell, but also as a signalling molecule regulating many cell processes [7,8]. Adenosine receptors (AR) are a subfamily of highly conserved G protein-coupled receptors located in the membr...