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A ZnO/TiO2@MWCNTs nanocomposite as an effective catalyst was employed for generating quinolinoquinazoline derivatives in high yields. These new compounds were synthesized by using multicomponent reaction of quinoline, isothiocyanate, 6‐amino‐2‐(prop‐1‐en‐2‐yl)‐1H‐indole‐5‐carbaldehyde, primary amines, and dimethyl acetylenedicarboxylate in aqueous media. It should be mentioned that the high performance of nanocatalyst was synthesized by using water extract of Aloe vera, which was utilized in these reactions for many times to confirm the reusability of nanocatalyst. The antioxidant property of new synthesized quinolinoquinazoline was evaluated by two procedures. Also, the antimicrobial activity of newly generated quinolinoquinazoline was evaluated by disk distribution process utilizing two kinds of Gram‐negative bacteria and Gram‐positive bacteria, proving bacterial growth was stopped by using of these compounds. Applied to the preparation of quinolinoquinazoline derivatives, this method has short reaction times, high product yields, and the ability to separate catalyst and product using simple procedures. [ABSTRACT FROM AUTHOR]

A simple, green and high-yielding procedure for the synthesis of 4-substituted-2-(alkylsulfanyl)thiazoles from the reaction of dithiocarbamates and α-halocarbonyl containing compounds in water is described. Also, a one-pot, two-step procedure for the synthesis of 2-(alkylsulfanyl)thiazoles from acetophenone and dithiocarbamates was developed. [ABSTRACT FROM AUTHOR]

The facile procedure allows the synthesis of thiazoles from α-haloketones and dithiocarbamates. [ABSTRACT FROM AUTHOR]

The interaction of nickel (II) phthalocyanine tetrasulfonic acid tetrasodium salt with bovine serum albumin (BSA) has been investigated by combination of fluorescence, UV-vis absorption, Fourier transform infrared (FT-IR), and circular dichorism (CD) spectroscopies as well as through molecular docking. Fluorescence quenching and absorption spectra were investigated as a mean for estimating the binding parameters. Analysis of fluorescence quenching data at different temperatures was performed in order to specify the thermodynamics parameters for interactions of phthalocyanine complex with BSA. According to experimental data it was suggested that phthalocyanine had a significant binding affinity to BSA and the process was entropy driven. Based on the results of molecular docking it was indicated that the main active binding site for this phthalocyanine complex is site I in subdomain IIA of BSA. The results provide useful information for understanding the binding mechanism of anticancer drug-albumin and gives insight into the biological activity and metabolism of the drug in blood. [ABSTRACT FROM AUTHOR]

Abstract S. aureus is one of important causes of disease, food poisoning in humans and animals. The generally methods for detection of S. aureus is time consuming. Therefore, a new method is necessary for rapid, sensitive and specific diagnosis of S. aureus. In the present study, two probes and a Bio-barcode DNA were designed for detection of S. aureus (Protein A). Firstly, magnetic nanoparticle (MNPs) and gold nanoparticle (AuNPs) were synthesized at 80 °C and 100 °C, respectively. The AuNPs and the MNPs were functionalized with probe1, Bio-barcode DNA and probe2, respectively. Target DNA was added into the nanomaterial's system containing bio-barcode DNA-AuNPs-probe1 and probe2-MNPs to formed bio-barcode DNA-AuNPs-probe1-target DNA-probe2-MNPs complex. The bio-barcode DNA-AuNPs-probe1-target DNA-probe2-MNPs complex was separated with magnetic field. Finally, the bio-barcode DNA was released from surface of complex using DTT (0.8 M) and there was isolated of nanoparticles by magnetic field and centrifuge. The fluorescence intensity of bio-barcode DNA was measured in different concentrations of S. aureus (101 to 108 CFU mL−1) by fluorescence spectrophotometry. The results showed that standard curve was linearly from 102 to 107 CFU mL−1. Limit of detection of bio-barcode assay for both PBS and real samples was 86 CFU mL−1. [ABSTRACT FROM AUTHOR]

Abstract Biosensors and whole cell biosensors consisting of biological molecules and living cells can sense a special stimulus on a living system and convert it to a measurable signal. A major group of them are the bioluminescent sensors derived from luciferases. This type of biosensors has a broad application in molecular biology and imaging systems. In this project, a luciferase-based biosensor for detecting and measuring caspase-9 activity is designed and constructed using the circular permutation strategy. The spectroscopic method results reveal changes in the biosensor structure. Additionally, its activity is examined in a cell-free coupled assay system. Afterward, the biosensor is utilized for measuring the cellular caspase-9 activity upon apoptosis induction in a cancer cell line. In following the gene of biosensor is sub-cloned into a eukaryotic vector and transfected to HEK293T cell line and then its activity is measured upon apoptosis induction in the presence and absence of a caspase-9 inhibitor. The obtained results show that the designed biosensor detects the caspase-9 activity in the cell-free and cell-based systems. Graphical abstract A new caspase-9 biosensor, which has been built by inactivating luciferase through circular permutation and connecting the fragments through a protease site (LEHD). In the presence of active form of caspase-9, peptide backbone cleavage occurs due to the protease activity of caspase-9, thereafter, the spliced luciferase will be active and regain its bioluminescent activity in the presence of substrate and it can be detected by measuring light emission at 482 nm. Therefore, emitted light can be attributed to the caspase-9 activity and apoptosis will be recognized. The biosensor has been constructed for cell-free and cell-based systems. Image 1 Highlights • A luciferase based biosensor for measuring caspase-9 activity has been constructed using circular permutation strategy. • The designed biosensor detects the caspase-9 activity in a cell-free coupled assay system. • The designed biosensor can be implemented as a cell-based biosensor to detect cellular caspase-9 activity and apoptosis. [ABSTRACT FROM AUTHOR]

G-quadruplexes are formed by association of DNA strands containing multiple contiguous guanines. The capability of drugs to induce formation or stabilize G-quadruplexes is an active area of cancer therapy investigation. We evaluated interaction between two cationic tetrapyridinoporphyrazines with Na and K forms of human telomeric G-quadruplex DNA by chemometrics method. An antiparallel quadruplex structure was found to be stabilized more greatly by these two isomers in the presence of K and Na ions. Equilibrium model of a ligand binding with DNA oligomer has been considered as a process of small molecule adsorption on to a lattice of multiple binding sites. In multivariate analysis methods, it is accounted this assertion that during saturation of the macromolecule by a ligand should expect effect of cooperativity due to changes in DNA conformation or the mutual influence between bound ligands. Such phenomenon cannot be entirely described by the classical stepwise complex formation model. From the results of absorption and circular dichroism measurements, the unique site for the ligand binding is suggested to be the intercalating in guanine tetrad plane quadruplex. We found a 2:1 binding stoichiometry for both ligands and Tel22. [ABSTRACT FROM AUTHOR]

Ultrasensitive DNA based fluorescent assay is used for the determination of Vibrio cholera O1 OmpW gene. OmpW as a surface adherence protein plays a major role in virulence of bacteria with high gene expression. In the present study, two nanoparticles including gold nanoparticles (AuNPs) and magnetic nanoparticles (MNPs) were used. MNPs were functionalized with the first target-specific DNA probe1, which can recognize one end of the target DNA sequence (t DNA) and the AuNPs were functionalized with the second target-specific DNA FAM-probe 2 which can recognize the other end of the target gene. After hybridization of probes with the target DNA, the sandwich structure was formed as MNPs-probe1-target DNA-FAM-probe2-AuNPs by applying the magnetic field to separate the sandwich complex from no hybridized materials. Dithiothreitol (DTT) was used to decompose the sandwich structures and release the probes from target DNA and nanoparticles. Then, fluorescence emission of the released FAM probe 2 on surface AuNPs was detected by fluorescence spectrophotometry. The resulting nanomaterial system demonstrated excellent sensitivity (LOD = 2.34 ng mL −1 ) with good linear relationship (R 2 = 0.9989) between target DNA and great selectivity. In conclusion, the present method has a good potential as a rapid detector of bacteria and other infection. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was investigating the effects of three antiinflammatory drugs, on Sirolimus protein biding. The binding site of Sirolimus on human serum albumin (HSA) was also determined. Methods: Six different concentrations of Sirolimus were separately exposed to HSA at pH 7.4 and 37°C. Ultrafiltration method was used for separating free drug; then free drug concentrations were measured by HPLC. Finally, Sirolimus protein binding parameters was calculated using Scatchard plots. The same processes were conducted in the presence of NSAIDs at lower concentration of albumin and different pH conditions. To characterize the binding site of Sirolimus on albumin, the free concentration of warfarin sodium and Diazepam, site I and II specific probes, bound to albumin were measured upon the addition of increasing Sirolimus concentrations. Results: Based on the obtained results presence of Diclofenac, Piroxicam and Naproxen, could significantly decrease the percentage of Sirolimus protein binding. The Binding reduction was the most in the presence of Piroxicam. Sirolimus-NSAIDs interactions were increased in higher pH values and also in lower albumin concentrations. Probe displacement study showed that Sirolimus may mainly bind to site I on albumin molecule. Conclusion: More considerations in co-administration of NSAIDs and Sirolimus is recommended. [ABSTRACT FROM AUTHOR]

Abstract: Interaction of N,N′,N″,N‴-tetramethyltetra-2,3-pyridinoporphyrazinatocopper(II), ([Cu(2,3-tmtppa)]4+) and N,N′,N″,N‴-tetramethyltetra-3,4-pyridinoporphyrazinatocopper(II), ([Cu(3,4-tmtppa)]4+) with calf thymus DNA was studied in 1mM phosphate buffer and low ionic strength (5mM NaCl) at various temperatures by UV-visible and circular dichroism (CD) spectroscopies and viscometric method. The binding constants were determined from the changes in the visible part of porphyrazine complexes spectra using SQUAD software. The values of K have been obtained (7.9±0.4)×104 and (2.2±0.1)×105 M−1 for [Cu(2,3-tmtppa)]4+ and [Cu(3,4-tmtppa)]4+, respectively at 27°C. The higher affinity of 3,4-isomer of Cu complex towards DNA with respect to the 2,3-isomer was attributed to favorable external positioning of the cationic charges in former, which enables superior interaction with the DNA duplex. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) were calculated by van''t Hoff equation. The enthalpy and entropy changes were determined, +34.2±3.6kJmol−1 and +207.8±12.70Jmol−1 K−1 for [Cu(2,3-tmtppa)]4+ and +49.7±2.1kJmol−1 and +267.8±7.9Jmol−1 K−1 for [Cu(3,4-tmtppa)]4+. The existence of extensive hypochromicity, large red shift and negative CD in the visible part of [Cu(3,4-tmtppa)]4+ spectra suggested an intercalation binding mode. Analysis of the moderate hypochromicity, red shift and bisignate CD in the Q-band absorption region of [Cu(2,3-tmtppa)]4+ spectra possibly led us to the coexistence of intercalation and outside binding modes. The influence of the ionic strength on the binding parameters and binding modes was investigated. The results show that increase in ionic strength causes the decrease in the binding constants. It was also concluded that increase in ionic strength affects the binding characteristics of positively charged complexes with DNA. The increase in DNA viscosity in the presence of Cu–tmtppa complexes is attributed to the lengthening of DNA helix due to the intercalation. This result is consistent with conclusions obtained from the spectroscopic techniques. [Copyright &y& Elsevier]