Dermatan Sulfate Affects Breast Cancer Cell Function via the Induction of Necroptosis

Dermatan sulfate (DS) is widespread in the extracellular matrix (ECM) of animal tissues. This glycosaminoglycan is characterized by a variable structure, which is reflected in the heterogeneity of its sulfation pattern. The sulfate groups are responsible for the binding properties of DS, which determine an interaction profile of this glycan. However, the detailed role of DS in biological processes such as the neoplasm is still poorly understood. The aim of the study was to assess the effects of the structural variants of DS on breast cancer cells. We found that DS isoforms from normal and fibrotic fascia as well as from intestinal mucosa were able to quickly induce oxidative stress in the cytoplasm and affect the mitochondrial function in luminal breast cancer cells. Moreover, the variants caused the necroptosis of the cells most likely via the first of these mechanisms. This death was responsible for a reduction in the viability and number of breast cancer cells. However, the dynamics and intensity of all of the DS variants-triggered effects were strongly dependent on the cell type and the structure of these molecules. The most pronounced activity was demonstrated by those variants that shared structural features with the DS from the tumor niche.

Interaction of ionic liquids with human serum albumin in the view of bioconcentration: a preliminary study

Bioaccumulation potential is critical in PBT and risk assessment of chemicals. However, for ionic liquids (ILs), this aspect remains neglected. It is especially important to fill this gap, because for this group of compounds, existing data confirm their risk of being environmentally persistent and toxicity. Moreover, considering preliminary reports on the interactions of ILs with lipids, it may be assumed that ILs have a higher potential for bioaccumulation than indicated by previous estimations built upon octanol–water partition coefficients. Moreover, the bioconcentration of ionizable chemical compounds may also be strongly related to plasma protein contents. Therefore, in this work, the affinity of a set of imidazolium cations and organic anions, and their combination to human serum albumin (HSA) was determined. The obtained results reveal that both cations and anions can be strongly bound to HSA, and blood proteins might play an important role in overall bioaccumulation. Furthermore, it was observed that HSA binding properties towards IL cations depend on the hydrophobicity of cations. The obtained data also provide indication that cation–anion interaction may affect ILs ions affinity to HSA.

De-Powdering Effect of Foundry Sand for Cement Casting

With the development of the powder bed 3D printing process, sand casting can be performed with methods that are more advanced than the traditional ones, thus enabling new research on applied materials. When sand is 3D-printed with cement as a binder, its casting performance is improved and sufficient thermal stability of conventional organic and inorganic binders is ensured. In this study, to ensure high resolution and strength in a physical and simple mixture of cement and sand, the compatibility for casting was confirmed using submicron-level cement with ingredients and sizes similar to commercial sand, which is uniformly controlled at 4 µm, instead of conventional sand. To enable quick 3D printing, calcium aluminate cement, which has quick binding properties, was used for high-temperature casting. The strength up to 6 h after hydration was compared to determine the curing rate of silica, mullite, and alumina sand containing cement components. By investigating the change in strength due to heat treatment and comparing the adhesion drop test results after powder bed formation, the material containing silica sand was determined as the most suitable for powder layer 3D printing for application to the mold.

Studies on Lectin Mediated Agglutination Reaction on Red Blood Cell Surface Antigens Using Hot and Cold Water Plant Extracts

Lectin has various physiological roles in cell agglutination, based on their carbohydrate-binding properties, plant lectins are widely used for the detection, segregation, and characterization of glycoconjugates. Rhesus (Rh) factor is a protein that is inherited and found on the surface of red blood cells. If the surface protein is present, the RBC is Rh positive; otherwise, it is Rh-negative in nature. In this paper, we use agglutination reactions to investigate the effect of different cold and hot water extracted plants on RBC antigens as an alternative to commercial monoclonal antibodies. Extensive research on the sequence homology and 3-D structure of various plant lectins suggests that they have been conserved throughout evolution and may play important physiological roles that are still unknown.

Evolutionary adaptation of DHFR via expression of enzyme isoforms with various binding properties and dynamics behavior: a bioinformatics and computational study

We compared the binding properties and dynamics of three experimentally reviewed isoforms of human dihydrofolate reductase (DHFR). The cytoplasmic variants including isoforms1 and 2 (iso1 and iso2) are produced by alternative splicing; while the mitochondrial form is located in the mitochondria. The iso1 as the canonical sequence contains 187 residues, and iso2 differs from the iso1, where it has 1–52 residues missing at the N-terminus of canonical sequence. Here, the structural models of the iso2 and mitochondrial forms were constructed by the MODELLER program using the crystal structure of the iso1 as the template. Bioinformatics analysis on ligand-bearing structures demonstrates that mitochondrial variant forms more stable complex with ligands compared with iso1 and 2, indicating their different binding properties. The root mean square fluctuation (RMSF) data suggest that C-terminus of iso1 contains two representative highly flexible fragments, while iso2 contains a highly flexible fragment at N-terminus end. Interestingly, both ends of mitochondrial variant have a degree of rigidity. Finally, the observation of differences in structural dynamics and binding properties predicts that the simultaneous existence of enzyme isoforms is a way to increase the speed of the enzyme maneuver in response to various environmental conditions. This prediction needs to be tested experimentally.

Assessment of the Optimum Linker Tethering Site of Alternariol Haptens for Antibody Generation and Immunoassay Development

Immunochemical methods for mycotoxin analysis require antigens with well-defined structures and antibodies with outstanding binding properties. Immunoreagents for the mycotoxins alternariol and/or alternariol monomethyl ether have typically been obtained with chemically uncharacterized haptens, and antigen conjugates have most likely been prepared with mixtures of functionalized molecules. For the first time, total synthesis was performed, in the present study, to obtain two haptens with opposite linker attachment locations. The functionalized synthetic haptens were purified and deeply characterized by different spectrometric methods, allowing the preparation of bioconjugates with unequivocal structures. Direct and indirect competitive enzyme-linked immunosorbent assays, using homologous and heterologous conjugates, were employed to extensively evaluate the generated immunoreagents. Antibodies with high affinity were raised from conjugates of both haptens, and a structure-activity relationship between the synthetic haptens and the specificity of the generated antibodies could be established. These results pave the way for the development of novel highly sensitive immunoassays selective of one or two of these Alternaria mycotoxins.

A Comparative Study on Nickel Binding to Hpn-like Polypeptides from Two Helicobacter pylori Strains

Combined potentiometric titration and isothermal titration calorimetry (ITC) methods were used to study the interactions of nickel(II) ions with the N-terminal fragments and histidine-rich fragments of Hpn-like protein from two Helicobacter pylori strains (11637 and 26695). The ITC measurements were performed at various temperatures and buffers in order to extract proton-independent reaction enthalpies of nickel binding to each of the studied protein fragments. We bring up the problem of ITC results of nickel binding to the Hpn-like protein being not always compatible with those from potentiometry and MS regarding the stoichiometry and affinity. The roles of the ATCUN motif and multiple His and Gln residues in Ni(II) binding are discussed. The results provided the possibility to compare the Ni(II) binding properties between N-terminal and histidine-rich part of Hpn-like protein and between N-terminal parts of two Hpn-like strains, which differ mainly in the number of glutamine residues.