Regulation of Selenium/Sulfur Interactions to Enhance Chemopreventive Effects: Lessons to Learn from Brassicaceae

Selenium (Se) is an essential trace element, which represents an integral part of glutathione peroxidase and other selenoproteins involved in the protection of cells against oxidative damage. Selenomethionine (SeMet), selenocysteine (SeCys), and methylselenocysteine (MeSeCys) are the forms of Se that occur in living systems. Se-containing compounds have been found to reduce carcinogenesis of animal models, and dietary supplemental Se might decrease cancer risk. Se is mainly taken up by plant roots in the form of selenate via high-affinity sulfate transporters. Consequently, owing to the chemical similarity between Se and sulfur (S), the availability of S plays a key role in Se accumulation owing to competition effects in absorption, translocation, and assimilation. Moreover, naturally occurring S-containing compounds have proven to exhibit anticancer potential, in addition to other bioactivities. Therefore, it is important to understand the interaction between Se and S, which depends on Se/S ratio in the plant or/and in the growth medium. Brassicaceae (also known as cabbage or mustard family) is an important family of flowering plants that are grown worldwide and have a vital role in agriculture and populations’ health. In this review we discuss the distribution and further interactions between S and Se in Brassicaceae and provide several examples of Se or Se/S biofortifications’ experiments in brassica vegetables that induced the chemopreventive effects of these crops by enhancing the production of Se- or/and S-containing natural compounds. Extensive further research is required to understand Se/S uptake, translocation, and assimilation and to investigate their potential role in producing anticancer drugs.     

Characterization of new Co(II) complexes and photographic monitoring for their toxic impact on breast cancer cells according to simulation study

Five new nitrogen-rich ligands (thioanhydrides) were synthesized and fully characterized. Then, their corresponding Co(II) complexes were prepared and also elucidated by analytical and spectral conformational techniques. First of all, the mono-negative tri-dentate mode was proposed with all derivatives towards mono-nuclear central atom. According to ligand field transitions and magnetic susceptibility values, the square-planar as well as octahedral geometries were the forms suggested. The presence of water molecules was investigated thermally. For conformational implementation under optimal conditions, energy minimization was carried out and fundamental data were obtained and studied. In silico investigation was carried out using the MOE docking approach to predict the inhibition activity for the new compounds. The Co(II)– 3e complex played an excellent inhibitory role. After that and based on preliminary results, in vitro antitumor screening against MCF-7 cell line was conducted for all Co(II) complexes. The results were consistent with that for standard drug (doxorubicin), and the inhibition feature for the complexes was ranked. Through photographic monitoring, outstanding inhibition activity towards breast cancer spreading was recorded for the Co(II)– 3e complex, which coincides well with MOE docking data.     

Exploring the physicochemical and morphological properties of peptide-hybridized dendrimers (DendriPeps) and their aggregates

This article presents an integrated experimental and computational study of DendriPeps, a novel class of dendrimers featuring a polyamidoamine (PAMAM) backbone hybridized with peptide segments. Hydroxyl-terminated Generation 2 (G.2) DendriPeps, comprising either four lysines (Lys) or four glutamic acids (Glu), and G.3 DendriPeps, comprising 8 Lys or 8 Glu, were first characterized in terms of hydrodynamic radius (R_h) and ζ-potential in aqueous solution. Unlike PAMAM dendrimers, DendriPeps form aggregates with R_h between 60 and 980 nm and ζ-potential between −130 and 80 mV despite their strong net charge. Upon application of shear, all aggregates disassemble into monomeric DendriPeps (R_h ~ 1–3 nm), but reform rapidly as shear is removed. Rheological characterization confirmed that DendriPep aggregates are disrupted by mild shear, but reform reversibly. Molecular dynamics simulations, informed by titrimetry, suggest that DendriPep aggregation derives from their multipolar structure and ability to rearrange the intermolecular/intramolecular pairing of titratable moieties at different pH values.     

Experimental investigation of TiO2–water nanofluid flow and heat transfer inside wavy mini-channel heat sinks

Journal of Thermal Analysis and Calorimetry - The present study comprises experimental investigation on heat transfer and hydrodynamic characteristics of TiO2 nanofluid as coolant in wavy channel...     

L-Glutaminase Synthesis by Marine Halomonas meridiana Isolated from the Red Sea and Its Efficiency against Colorectal Cancer Cell Lines

L-glutaminase is an important anticancer agent that is used extensively worldwide by depriving cancer cells of L-glutamine. The marine bacterium, Halomonas meridian was isolated from the Red Sea and selected as the more active L-glutaminase-producing bacteria. L-glutaminase fermentation was optimized at 36 h, pH 8.0, 37 °C, and 3.0% NaCl, using glucose at 1.5% and soybean meal at 2%. The purified enzyme showed a specific activity of 36.08 U/mg, and the molecular weight was found to be 57 kDa by the SDS-PAGE analysis. The enzyme was highly active at pH 8.0 and 37 °C. The kinetics’ parameters of Km and Vmax were 12.2 × 10⁻⁶ M and 121.95 μmol/mL/min, respectively, which reflects a higher affinity for its substrate. The anticancer efficiency of the enzyme showed significant toxic activity toward colorectal adenocarcinoma cells; LS 174 T (IC50 7.0 μg/mL) and HCT 116 (IC50 13.2 μg/mL). A higher incidence of cell death was observed with early apoptosis in HCT 116 than in LS 174 T, whereas late apoptosis was observed in LS 174 T more than in HCT 116. Also, the L-glutaminase induction nuclear fragmentation in HCT 116 was more than that in the LS 174T cells. This is the first report on Halomonas meridiana as an L-glutaminase producer that is used as an anti-colorectal cancer agent.     

Charge-transfer complexes of two highly efficient drugs with σ- and π-acceptors: Spectroscopic,thermal, and surface morphology characteristics

Considerable attention has recently been devoted to the formation of stable charge-transfer (CT) complexes that result from the reaction of drugs with acceptors. Intermolecular CT interactions of two drugs, barbituratic acid (Bar) and ephedrine hydrochloride (Eph), with different σ- and π-acceptors have been studied stoichiometrically, structurally (IR, Raman, ¹H NMR, and UV-Vis spectroscopy), thermally, and morphologically (SEM).     

Synthesis of sulfur-containing heterocycles via ring enlargement

The current review deals with the use of ring expansion reactions for the synthesis of sulfur-containing heterocycles. Ring enlargement offers by far a convenient method for the synthesis of ‘medium-sized ring systems’, which are usually difficult to obtain or even produced in low yields. These reactions are often catalytically processed starting from a single cyclic precursor and, therefore, are superior to alternative classical iterative synthetic approaches in terms of atomic and conversion efficiency. The current review aims to shed light on the synthetic approaches that exist to afford medium-sized sulfur heterocycles from preexisting smaller rings (e.g., three-, four-, five-, six- and seven-membered rings).     

A New Multi-tanh-Based Non-linear Function Synthesiser

A new complementary metal-oxide-semiconductor transadmittance-mode with input voltage and output current, analogue non-linear odd-function synthesiser is presented. The proposed circuit is based on the assumption that a non-linear odd- function can be approximated by the summation of hyperbolic tangent (tanh) functions with different arguments. Each term of the tanh function expansion is realised by exploiting to advantage the inherent non-linearity of a current-controlled current-conveyor (CCCCII) (or an operational transconductance amplifier (OTA)) with a different bias current. The output currents of these CCCCIIs (OTAs) are weighted using the gains of current amplifiers. These weighted currents are algebraically added to form the required non-linear function. The proposed circuit is suitable for integration, can be easily extended to include higher order terms of the tanh-odd-function expansion and can be programmed to realise arbitrary hard non-linear odd-functions that cannot be easily realised using already existing techniques, based on the Taylor-series expansion, for synthesising non-linear functions. PSPICE simulation results, obtained from CCCCII-based realisations of selected hard non-linearities, demonstrating the functionality of the proposed circuit are included.     

Cog-MAC Protocol: Channel Allocation in Cognitive Ad Hoc Networks Based on the Game of Learning Automata

Wireless Personal Communications - Spectrum allocation is a major challenge in wireless ad hoc networks due to restrictions on the number of available communication channels and also passive...