Resorcylidene Aminoguanidine (RAG) Improves Cardiac Mitochondrial Bioenergetics Impaired by Hyperglycaemia in a Model of Experimental Diabetes

Diabetes is associated with a mitochondrial dysfunction. Hyperglycaemia is also clearly recognized as the primary culprit in the pathogenesis of cardiac complications. In response to glycation and oxidative stress, cardiac mitochondria undergo cumulative alterations, often leading to heart deterioration. There is a continuous search for innovative treatment strategies for protecting the heart mitochondria from the destructive impact of diabetes. Aminoguanidine derivatives have been successfully used in animal model studies on the treatment of experimental diabetes, as well as the diabetes-driven dysfunctions of peripheral tissues and cells. Considerable attention has been paid particularly to β-resorcylidene aminoguanidine (RAG), often shown as the efficient anti-glycation and anti-oxidant agent in both animal studies and in vitro experiments. The aim of the present study was to test the hypothesis that RAG improves oxidative phosphorylation and electron transport capacity in mitochondria impaired by hyperglycaemia. Diabetes mellitus was induced in Wistar rats by a single intraperitoneal injection of streptozotocin (70 mg/kg body weight). Heart mitochondria were isolated from healthy rats and rats with streptozotocin-diabetes. Mitochondrial respiratory capacity was measured by high resolution respirometry with the OROBOROS Oxygraph-2k according to experimental protocol including respiratory substrates and inhibitors. The results revealed that RAG protects the heart against diabetes-associated injury by improving the mitochondrial bioenergetics, thus suggesting a possible novel pharmacological strategy for cardioprotection.     

Environmental applications of biosurfactants: recent advances

Increasing public awareness of environmental pollution influences the search and development of technologies that help in clean up of organic and inorganic contaminants such as hydrocarbons and metals. An alternative and eco-friendly method of remediation technology of environments contaminated with these pollutants is the use of biosurfactants and biosurfactant-producing microorganisms. The diversity of biosurfactants makes them an attractive group of compounds for potential use in a wide variety of industrial and biotechnological applications. The purpose of this review is to provide a comprehensive overview of advances in the applications of biosurfactants and biosurfactant-producing microorganisms in hydrocarbon and metal remediation technologies.     

Electrodeposition of CdS from acidic aqueous thiosulfate solution—Invesitigation of the mechanism by electrochemical quartz microbalance technique

Electrochemical quartz crystal microbalance was used to study mechanism of cathodic electrodeposition of CdS from acidic aqueous solutions containing 0.01 M Cd(ClO₄)₂ and 0.1 M Na₂S₂O₃ as a source of sulfur. Experiments were performed by means of cyclic voltammetry and potentiostatic method. A comparison of gravimetric and current responses at pH 3 and 4 allowed for determination of the potential range in which side reactions of reduction of SO₃²⁻ and H⁺ ions compete most strongly with formation of CdS. The film thickness was determined by means of two methods: from AFM profiles and EQCM measurements.     

Behavior of Cetyltrimethylammonium Bromide, tert-Octylphenol (9.5 EO) Ethoxylate and Ethanol Mixtures at the Water–Air Interface

The surface tension measurements of aqueous solutions of p‐(1,1,3,3‐tetramethylbutyl)phenoxypoly(9.5)ethylene glycol or tert‐octylphenol ethoxylate (TOP10) and cetyltrimethylammonium bromide (CTAB) mixtures with ethanol were carried out in the range of the total concentration of CTAB and TOP10 mixtures from 1 × 10^?7 to 1 × 10^?2 M and ethanol from 0 to 17.13 M. In the CTAB and TOP10 mixtures, the mole fractions of TOP10 were equal to 0.2; 0.4; 0.6; and 0.8, respectively. The results obtained were compared to those calculated from the Fainerman and Miller equation developed for ideal mixtures of two homologous surfactants, as well as from the Connors equation derived for the concentrated organic solutions. The calculations of the surface tension from the Fainerman and Miller equation were carried out treating the solvent and solute in a few different ways. The differences between the measured and calculated values of the surface tension were discussed in the light of molecular interaction parameter and the composition of the surface layer. The composition of the mixed surface layer at the solution‐air interface was evaluated according to Rosen using the nonideal solution theory with the assumption that water with ethanol is a mixed solvent. Knowing the values of mole fractions of CTAB and TOP10 in the surface layer, the molecular interaction parameter was determined.     

Associations between Oil Yield and Profile of Fatty Acids,Sterols, Squalene,Carotenoids, and Tocopherols in Seed Oil of Selected Japanese Quince Genotypes during Fruit Development

Tocopherols, phytosterols, carotenoids, and squalene are present in mature seeds of Japanese quince. Yet, little is known about the relationship between these compounds and oil yield during fruit and seed development. The profile change of lipophilic compounds during fruit and seed development in Japanese quince cultivars “Darius,” “Rondo,” and “Rasa” is investigated. It is shown here that during fruit and seed development, there is a significant reduction, three‐ to over tenfold, in the concentration of minor bioactive compounds in seed oil. It is recorded that delay between synthesis of tocopherols and oil in Japanese quince seeds during the fruit development results in a logarithmic relationship between the oil content and tocopherols concentration in the seed oil (R² = 0.980). Similar trends are observed between oil yield and phytosterols, and carotenoids (R² = 0.927 and R² = 0.959, respectively). The profile of fatty acids during the development of the seeds significantly is changed. The reduction of linoleic, palmitic, and gondoic acids levels and increment of oleic acid is noted. The oil content, profile of fatty acids, and concentration of bioactive compounds in all three genotypes of Japanese quince do not change significantly statistically during the last month of fruit development. Practical Applications: Some fruits are harvested at different degrees of maturity mainly due to a logistic issue and uneven ripening of fruits, which affects the chemical composition of whole fruit including seeds. Therefore, it would be good to know how the chemical composition is changing in plant material during development especially in the last month before harvest. Production of Japanese quince continues to rise year to year and with it the volume of generated by‐products such as seeds. This study demonstrates how it changes the oil content, profile of fatty acid, and concentration of tocopherols, squalene, phytosterols, and carotenoids in the seeds and seed oil of three Japanese quince cultivars “Rondo,” “Darius,” and “Rasa” during plant development. The provided information can be very useful for the manufactories oriented on the processing of by‐products, mainly seeds, generated by other branches of industry, for instance, fruit‐processing.     

Novel conventional and chelating anion exchange resins with amino ligands for sorption of silver

ABSTRACT

The polymeric resins containing diethylenetriamine, tetraethylenepentamine, 2-(diethylamino)ethanol, 1-methylimidazole, and 1,2-dimethylimidazole ligands have been synthesized from vinylbenzyl chloride-divinylbenzene copolymers and used in the removal of Ag(I) from chloride solution. The best Ag(I) sorption was reached in the case of 1-methylimidazole resin. Resins retain their capacity towards Ag(I) in five consecutive sorption/desorption cycles. The resins with imidazole ligands were highly selective for Ag(I) from synthetic chloride solution and they did not sorb chloride complexes of Cu(II). Additionally, the recovery of Ag(I) was tested from real chloride solution coming from leaching of the copper concentrate from Lubin Concentrator (KGHM Polska Mied? S.A.).     

Alternating Cationic-Hydrophobic Peptide/Peptoid Hybrids: Influence of Hydrophobicity on Antibacterial Activity and Cell Selectivity

The influence of hydrophobicity on antibacterial activity versus the effect on the viability of mammalian cells for peptide/peptoid hybrids was examined for oligomers based on the cationic Lys-like peptoid residue combined with each of 28 hydrophobic amino acids in an alternating sequence. Their relative hydrophobicity was correlated to activity against both Gram-negative and Gram-positive species, human red blood cells, and HepG2 cells. This identified hydrophobic side chains that confer potent antibacterial activity (e. g., MICs of 2–8 μg/mL against E. coli) and low toxicity toward mammalian cells (<10 % hemolysis at 400 μg/mL and IC₅₀>800 μg/mL for HepG2 viability). Most peptidomimetics retained activity against drug-resistant strains. These findings corroborate the hypothesis that for related peptidomimetics two hydrophobicity thresholds may be identified: i) it should exceed a certain level in order to confer antibacterial activity, and ii) there is an upper limit, beyond which cell selectivity is lost. It is envisioned that once identified for a given subclass of peptide-like antibacterials such thresholds can guide further optimisation.     

Al-Tolerant Barley Mutant hvatr.g Shows the ATR-Regulated DNA Damage Response to Maleic Acid Hydrazide

ATR, a DNA damage signaling kinase, is required for cell cycle checkpoint regulation and detecting DNA damage caused by genotoxic factors including Al³⁺ ions. We analyzed the function of the HvATR gene in response to chemical clastogen-maleic acid hydrazide (MH). For this purpose, the Al-tolerant barley TILLING mutant hvatr.g was used. We described the effects of MH on the nuclear genome of hvatr.g mutant and its WT parent cv. “Sebastian”, showing that the genotoxic effect measured by TUNEL test and frequency of cells with micronuclei was much stronger in hvatr.g than in WT. MH caused a significant decrease in the mitotic activity of root cells in both genotypes, however this effect was significantly stronger in “Sebastian”. The impact of MH on the roots cell cycle, analyzed using flow cytometry, showed no differences between the mutant and WT.     

α-Triazolylboronic Acids: A Promising Scaffold for Effective Inhibitors of KPCs

Boronic acids are known reversible covalent inhibitors of serine β-lactamases. The selectivity and high potency of specific boronates bearing an amide side chain that mimics the β-lactam's amide side chain have been advanced in several studies. Herein, we describe a new class of boronic acids in which the amide group is replaced by a bioisostere triazole. The boronic acids were obtained in a two-step synthesis that relies on the solid and versatile copper-catalyzed azide–alkyne cycloaddition (CuAAC) followed by boronate deprotection. All of the compounds show very good inhibition of the Klebsiella pneumoniae carbapenemase KPC-2, with K_i values ranging from 1 nM to 1 μM, and most of them are able to restore cefepime activity against K. pneumoniae harboring bla_KPC-2. In particular, compound 1 e , bearing a sulfonamide substituted by a thiophene ring, proved to be an excellent KPC-2 inhibitor (K_i=30 nM); it restored cefepime susceptibility in KPC-Kpn cells (MIC=0.5 μg/mL) with values similar to that of vaborbactam (K_i=20 nM, MIC in KPC-Kpn 0.5 μg/mL). Our findings suggest that α-triazolylboronates might represent an effective scaffold for the treatment of KPC-mediated infections.     

Multiscale approach to the morphology,structure, and segmental dynamics of complex degradable aliphatic polyurethanes

A multiscale approach spanning from the segmental (subnanometer) up to micrometer level was applied for detailed study of the self‐assembly of aliphatic block polyurethane (PU) elastomers. To understand the principles of the self‐organization of hard and soft segments in the complex multi‐component systems, several two‐component model PU samples, that is, the products of 1,6‐diisocyanatohexane (HDI) with three diols differing in the length and constitution were also prepared, characterized, and investigated: (i) polycarbonate‐based macrodiol (MD), (ii) biodegradable oligomeric diol (DL‐L; product of butane‐1,4‐diol and D,L‐lactide), and (iii) butane‐1,4‐diol (BD). The study (particularly ¹³C‐¹H PILGRIM NMR spectra) reveals complex internal organization and interesting (application appealing) behavior of multi‐component PUs. Hard segments (HDI+BD products) feature self‐assembled and significantly folded chain conformations with interdomain spacing 15–22 nm (small‐angle X‐ray scattering analysis). The small domains are hierarchically assembled in various structural formations of µm size (spherulites) depending on PU composition, as detected by transmission electron microscopy and atomic force microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41590.