The interaction of human CK2α (hCK2α) with nine halogenated benzotriazoles, TBBt and its analogues representing all possible patterns of halogenation on the benzene ring of benzotriazole, was studied by biophysical methods. Thermal stability of protein-ligand complexes, monitored by calorimetric (DSC) and optical (DSF) methods, showed that the increase in the mid-point temperature for unfolding of protein-ligand complexes (i.e. potency of ligand binding to hCK2α) follow the inhibitory activities determined by biochemical assays. The dissociation constant for the ATP-hCK2α complex was estimated with the aid of microscale thermophoresis (MST) as 4.3±1.8 μM, and MST-derived dissociation constants determined for halogenated benzotriazoles, when converted according to known ATP concentrations, perfectly reconstruct IC50 values determined by the biochemical assays. Ligand-dependent quenching of tyrosine fluorescence, together with molecular modeling and DSC-derived heats of unfolding, support the hypothesis that halogenated benzotriazoles bind in at least two alternative orientations, and those that are efficient hCK2α inhibitors bind in the orientation which TBBt adopts in its complex with maize CK2α. DSC-derived apparent heat for ligand binding (ΔΔHbind) is driven by intermolecular electrostatic interactions between Lys68 and the triazole ring of the ligand, as indicated by a good correlation between ΔΔHbind and ligand pKa. Overall results, additionally supported by molecular modeling, confirm that a balance of hydrophobic and electrostatic interactions contribute predominantly (~40 kJ/mol), relative to possible intermolecular halogen/hydrogen bonding (less than 10 kJ/mol), in binding of halogenated benzotriazoles to the ATP-binding site of hCK2α. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases.

The effect of marine calcite (containing calcium and silicon mainly) foliar fertilization on the sugar beet root yield and technological quality relative to the control (treatment 0) was investigated. Study was conducted in 2011-2012 in the southeastern region of Poland, in Sahryń (50°41'N, 23°46'E). The cultivar of sugar beet was Danuśka KWS. Two treatments of foliar fertilization: (1) treatment (in the stage of 4-6 sugar leaves -262.0 g Ca/ha, 79.9 g Si/ha, and three weeks later -524.0 g Ca/ha, 159.8 g Si/ha); and (2) treatment (in the stage of 4-6 sugar leaves -524.0 g Ca/ha, 159.8 g Si/ha, three weeks later -524.0 g Ca/ha, 159.8 g Si/ha). Calcium and silicon foliar fertilization resulted in increases of: (1) the root yield (average for both treatments about 13.1%; (2) the leaf yield (about 21.0%); (3) the biological sugar yield (about 15.5%), and (4) technological yield of sugar (about 17.7%) compared with the control treatment. At the same time a positive effect on the roots technological quality was found. It was a significant reduction of alpha-amino-nitrogen content and tended to reduce the content of potassium and sodium.

The effect of marine calcite (containing calcium and silicon mainly) foliar fertilization on the sugar beet root yield and technological quality relative to the control (treatment 0) was investigated. Study was conducted in 2011-2012 in the southeastern region of Poland, in Sahryń (50°41'N, 23°46'E). The cultivar of sugar beet was Danuśka KWS. Two treatments of foliar fertilization: (1) treatment (in the stage of 4-6 sugar leaves-262.0 g Ca/ha, 79.9 g Si/ha, and three weeks later-524.0 g Ca/ha, 159.8 g Si/ha); and (2) treatment (in the stage of 4-6 sugar leaves-524.0 g Ca/ha, 159.8 g Si/ha, three weeks later-524.0 g Ca/ha, 159.8 g Si/ha). Calcium and silicon foliar fertilization resulted in increases of: (1) the root yield (average for both treatments about 13.1%; (2) the leaf yield (about 21.0%); (3) the biological sugar yield (about 15.5%), and (4) technological yield of sugar (about 17.7%) compared with the control treatment. At the same time a positive effect on the roots technological quality was found. It was a significant reduction of alpha-amino-nitrogen content and tended to reduce the content of potassium and sodium.

The present study was conducted to assess the effect of various multinutrient foliar fertilization treatments on nutrient accumulation in the roots and leaves of sugar beet. The field experiment was performed in two growing seasons (2013 and 2014) in the southeastern region of Poland. The experiment was conducted as a randomized block design with four replications. To determine the content of the selected nutrients (Si, N, P, K, Mg, and Ca), samples of leaves and roots were collected during harvest. Fertilization treatments applied on the plants’ leaves affected the silicon (Si) content in the roots of sugar beet and the total Si uptake. Moreover, foliar fertilization had a significant effect on the P content in the leaves and the N and K contents in the roots. The Si content in the sugar beet leaves and roots ranged from 0.55 to 1.97 g kg−1 dry matter (d. m.) and from 0.49 to 1.59 g kg−1 d. m., respectively. The total Si uptake ranged from 20.3 to 46.7 kg ha−1. Most of the Si content taken up with each fertilization variant was accumulated in the roots. The yield of pure sugar was not correlated with the Si content in the leaves and roots.

Courgette is considered as a low-calorie vegetable with health-promoting properties. However, scientific publications focused on the profile and content of bioactive compounds in courgette, as well as the potential fruit quality modulating factors, are rare. Due to the high adaptability of courgette to weather and agronomic conditions, it is produced on a global scale. The aim of this study was to analyse the impact of organic versus conventional agronomic practices on the concentration of selected antioxidants in courgette fruits. Fruits of two courgette varieties (Astra Polka and Nimba) produced in an organic and conventional system were tested by high performance liquid chromatography (HPLC) to determine the content of polyphenols (flavonoids and phenolic acids), carotenoids, chlorophylls, and vitamin C. Organic courgette fruits were characterised by their significantly higher content of phenolic acids and flavonoids when compared to the conventionally grown fruit. The organic cultivation might be a good method to increase concentration of bioactive compounds with antioxidant properties in courgette fruits. Nevertheless, the identified trends should be further confirmed, with attention paid to other courgette varieties, as well as to the potential interactions between the plant genotype, agronomic system and the location-specific growing conditions.