No abstract

No abstract

No abstract

Lactate dehydrogenase (LDH) is an enzyme that catalyzes the reduction of nicotinamide adenine dinucleotide (NADH) and pyruvate to nicotinamide adenine dinucleotide (NAD+) and D‐lactate in the final step of anaerobic glycolysis. This enzyme belongs to the family of oxidoreductases. Humans possess two isoforms of LDH enzyme: NAD‐dependent L‐lactate dehydrogenase (L‐LDH) and NAD‐dependent D‐lactate dehydrogenase (D‐LDH). D‐LDH is released during tissue damage, and is a sign of diseases such as kidney stones, heart failure, and some types of cancers and appendicitis. Accordingly, the design and construction of biosensors for the determination of lactate levels are important. The thermal sensitivity of D‐LDH and low protein production in the host bacteria limit the use of this protein in certain applications. To solve these problems, two solutions were used in this study. First, the codon‐optimized 1008 bp D‐LDH gene fused with a histidine tag was cloned at the NcoI/XhoI sites and expressed in E. coli BL21. Second, a new metal–organic framework (Fe3O4NPs@Ni‐MOF) was synthesized and used for immobilization and stabilization of D‐LDH. Fe3O4NPs@Ni‐MOF core‐shell nanocomposites were characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometer, scanning electron microscopy, X‐ray diffraction, and the Brunauer–Emmett–Teller method. In comparison with the free enzyme, the immobilized enzyme presented better stability at high temperatures. The immobilization of the enzyme could be useful because most reactions happen at high temperatures in industry. To examine the effect of Fe3O4NPs@Ni‐MOF on the adsorption and conformation of D‐LDH at the atomistic level, a molecular dynamics simulation was carried out. Our study showed that the interaction between Fe3O4NPs@Ni‐MOF and D‐LDH involved van der Waals interactions, hydrophobic interaction energies, cation–π interaction between the Ni ions of the MOF with the enzyme residues and also, the hydrogen bond interactions between enzyme and heteroatoms in the MOF. Root mean square fluctuation and secondary structure analysis showed that Fe3O4NPs@Ni‐MOF protected the conformation of the enzyme.

No abstract

No abstract

Curcumin is known to exhibit antioxidant and tissue-healing properties and has recently attracted the attention of the biomedical community for potential use in advanced therapies. This work reports the formulation and characterization of oil-in-water F127 microemulsions to enhance the bioavailability of curcumin Microemulsions showed a high encapsulation efficiency and prolonged release. To investigate the interactions of curcumin with one unit of the polymeric chain of surfactant F127, ethyl butyrate, and sodium octanoate, as well as the interaction between ethyl butyrate and one unit of the F127 polymer chain, the Density Functional Theory (DFT) calculations at the M06-2X level of theory, were performed in water solution. The MTT assay was used to assess the cytotoxicity of free and encapsulated curcumin on non-malignant and malignant cell lines. Combination effects were calculated according to Chou-Talalay’s principles. Results of in vitro studies indicated that MCF7 and HepG2 cells were more sensitive to curcumin microemulsions. Moreover, a synergistic relationship was observed between curcumin microemulsions and cisplatin in all affected fractions of MCF7 and HepG2 cells (CI < 0.9). For in vivo investigation, thioacetamide-intoxicated rats received thioacetamide (100 mg/kg Sc) followed by curcumin microemulsions (30 mg/kg Ip). Thioacetamide-intoxicated rats showed elevated serum liver enzymes, blood urea nitrogen (BUN), and creatinine levels, and a significant reduction in liver superoxide dismutase (SOD) and catalase (CAT) activities (p < 0.05). Curcumin microemulsions reduced liver enzymes and serum creatinine and increased the activity of antioxidant enzymes in thioacetamide-treated rats in comparison to the untreated thioacetamide-intoxicated group. Histopathological investigations confirmed the biochemical findings. Overall, the current results showed the desirable hepatoprotective, nephroprotective, and anti-cancer effects of curcumin microemulsions.

Density functional theory (DFT) calculations at the B3LYP/6-31G* level are performed to investigate the adsorption properties and quantum molecular descriptors of H 2 S adsorbed on the external surface of (6,0) single-walled aluminum phosphide nanotube (AlPNT). The vibrational frequencies and physical properties such as dipole moment, chemical potential, chemical hardness and chemical electrophilicity of all studied configurations have been systematically explored. Also, the interaction of H 2 S gas and AlPNT on the basis of five reactivity descriptors such as the overall stabilization energy (DE SE(AB) ), the individual energy change of the acceptor (DE A(B) ), the individual energy change of donor (DE B(A) ), the global electrophilicity difference of AlPNT and H 2 S gas (Dw) and charge transfer (DN) has been explained. All adsorptions are electronically harmless processes and venial impacts on the energy gap of the AlP nanotube. The natural bond orbital calculations are done to derive natural atomic orbital occupancies. The H 2 S molecule physisorbed on the surface of pristine AlP nanotube with adsorption energy of about -20 kJ/mol. The AIM theory has been also used to examine the properties of the bond critical points: their electron densities and Laplacians. The adsorption energy of H 2 S molecule is not so large to hinder the recovery of the AlPNT, and therefore, the sensor will possess short recovery times. Electronic structures of pristine AlPNT and adsorbed H 2 S gas AlPNT models are examined by DFT calculations of chemical shielding (CS) parameters of 27 Al and 31 P atoms. The isotropic and anisotropic CS parameters are divided into layers based on the detection of similar electronic environments by the atomic sites of each layer.