Template reactions of 2-hydroxy-R-benzaldehyde-S-methylisothiosemicarbazones (R= 3methoxy or 4-hydroxy) with the corresponding aldehydes in the presence of FeCl 3 and NiCl 2 yielded N 1 ,N 4 -disalicylidene chelate complexes. The compounds were characterized by means of elemental and spectroscopic methods. The structure of complex 1 was determined by x-ray single crystal diffraction. Crystal data (Mo Kα; 296 K) are as follows: monoclinic space group P2 1 /c, a = 12.9857(8) Å, b = 7.8019(4) Å, c = 19.1976(12) Å, β = 101.655(5)°, Z = 4. Cytotoxic effects of the compounds were evaluated by MTT assay in K562 leukemia, ECV304 endothelial and normal mononuclear cells and DNA fragmentation analysis using the diphenylamine reaction were performed. The DNA binding capacity of thiosemicarbazones at IC 50 and different concentrations was investigated. The DNA fragmentation percentage of compound treated cells were higher than non-treated control cells but compound 3 (84%) was higher than the others. The interaction of compounds 1-4 and DNA was investigated voltammetrically by using nucleic acids modified electrodes after the double stranded fish sperm DNA (fsDNA), or poly (dA).poly (dT) was immobilized onto the surface of pencil graphite electrodes (PGEs). Accordingly, the oxidation signals of DNA bases; guanine and adenine were measured by using differential pulse voltammetry (DPV). The changes at the signals of guanine and adenine were evaluated before and after interaction process. The results indicated compound 3 was cytotoxic in very low concentrations in K562 leukemia cells unlike other cells and that could damage the DNA double stranded form, specifically the adenine base. Therefore, it may be a selective antileukemic effect and drug potential.thiosemicarbazones. Generally, the transition metals play a very important role in an organism and their complexes can interact non-covalently with nucleic acid by intercalation, groove-binding or external electrostatic binding for cations. 3,7,[19][20][21][22] There have been numerous studies in the literature investigating drug-DNA interactions by using conventional techniques such as HPLC, GC, and mass spectrometry. Considering the numerous advantages of electrochemical analysis techniques, the disadvantages of these conventional techniques arising from their complicated form of analysis have made them less preferable. Since the electroactivity of nucleic acids was discovered in the 1960s, 29 electrochemical nucleic acid biosensors, known as electrochemical genosensors, have frequently been preferred for recognition of (bio)molecule-DNA interactions. There are several research articles that investigated (bio)molecule-DNA interaction by using electrochemical techniques in the literature. [30][31][32][33][34][35][36] PGEs bring some crucial properties such as being robust, single-use, practical and having a large surface area. Their combination with electrochemical detection techniques provides fast, practical, accurate and time-saving analysis of target analytes. Moreover, th...

Diphtheria toxin (DT) and its N-terminal fragment A (FA) catalyse the transfer of the ADP-ribose moiety of nicotinamide adenine dinucleotide (NAD) into a covalent linkage with eukaryotic elongation factor 2 (eEF2). DT-induced cytotoxicity is versatile, and it includes DNA cleavage and the depolymerisation of actin filaments. The inhibition of the ADP-ribosyltransferase (ADPrT) activity of FA did not affect the deoxyribonuclease activity of FA or its interaction with actin. The toxin entry rate into cells (HUVEC) was determined by measuring the ADP-ribosyltransferase activity. DT uptake was nearly 80% after 30 min. The efficiency was determined as K m = 2.2 nM; V max = 0.25 pmol.min -1. The nuclease activity was tested with hyperchromicity experiments, and it was concluded that G-actin has an inhibitory effect on DT nuclease activity. In thepresence of DT and mutant of diphtheria toxin (CRM197), F-actin depolymerisation was determined with gel filtration, WB and fluorescence techniques. In the presence of DT and CRM197, 60-65% F-actin depolymerisation was observed. An in vitro FA-actin interaction and F-actin depolymerisation were reported in our previous paper. The present study thus confirms the depolymerisation of actin cytoskeleton in vivo.

It was shown by gel filtration and viscosity measurements that N-terminal fragment (FA) of diphtheria toxin (DT) can interact with both G- and F-actin (filamentous actin). Elution profiles on Sephadex G-100 indicated the formation of a binary complex of fragment A (FA) with globular actin monomer (G-actin), which was inhibited by gelsolin. Deoxyribonuclease I (DNase I) in turn appeared to interact with this complex. Tritiated FA was found to bind to F-actin stoichiometrically. This binding was inhibited again by gelsolin and G-actin, but not by DNase I. The binding of FA inhibited polymerization of G-actin and induced a time-dependent breakdown of F-actin under polymerization conditions. Inhibition of its ADP-ribosyltransferase activity did not have any effect on the interactions of FA with actin. FA interacted with actin also in the cell. After treatment of human umbilical vein endothelial cells (HUVEC) with biotin-labeled DT, Western blot analysis revealed predominantly the presence of actin in affinity-isolated complexes of the labeled FA. Similarly, FA was found in immunoaffinity-isolated complexes of actin.

The aim of this study was to investigate the effects of calcium silicate-based products on cytotoxicity in the 3T3 fibroblast and gelatinolytic activity of matrix metalloproteinases (MMPs). 3T3 fibroblasts were incubated directly with Ortho Mineral trioxide aggregate (MTA), BioAggregate, Biodentine, MTA Plus, MTA Angelus and MTA Cerkamed for 24 hours and seven days. The cytotoxicity was determined using an MTT assay. Supernatants were collected to determine MMP-2 and MMP-9. Data were analysed using IBM SPSS 22. Seventh day extracts of Ortho MTA and Biodentine showed reduced cell viability. Specific characterization of MMPs in cell culture demonstrated that MMP-2 (62 kPa) in the cell culture supernatants by gelatin zymography showed induced expression in four out of seven groups by 3T3 cells. No MMP-9 expression was observed. The cytotoxicity of materials revealed a significant difference in cell viability between the groups on the first and seventh days. The results of this study revealed minor cytotoxic effects for Ortho MTA and Biodentine. This study suggests that endodontic sealers induced production of MMP-2. MMP-9 might be expressed in small amounts when compared with MMP-2.

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