Analysis of phytochelatin-cadmium complexes from plant tissue culture using nano-electrospray ionization tandem mass spectrometry and capillary liquid chromatography/electrospray ionization tandem mass spectrometry.

Phytochelatins (PCs, also known as class III metallothioneins), a family of sulfhydryl-rich peptides with the formula (gamma-GluCys)(n)Gly(Pc(n), n = 2-11), are induced in plants, yeast and fungi exposed to heavy metals, and are thought to detoxify metals by forming PC- metal complexes. Although PCs have been detected, PC- metal complexes have not been well characterized. In this work, nano-electrospray ionization tandem mass spectrometry (nano-ESI-MS/MS) and capillary liquid chromatography/electrospray ionization tandem mass spectrometry (capillary LC/ESI-MS/MS) methods were used to analyze PC - Cd complexes isolated from Datura innoxia, also known as Jimsonweed, cell culture exposed to Cd. With nano-ESI-MS/MS and capillary LC/ESI-MS/MS we could simultaneously detect the presence of PCs and PC - Cd complexes from plant cell extracts, unambiguously identify these species and elucidate the nature of individual PC - Cd complexes. Phytochelatins with n = 3-6 were detected, as were PC - Cd complexes with PC(3), PC(4) and PC(5). This is the first study to report the size and nature of native PC - Cd complexes from plant tissue samples. These results demonstrate that the direct analysis of plant extracts using nano-ESI-MS/MS and capillary LC/ESI-MS/MS methods is simple and sensitive to the range of PCs and PC - Cd complexes in plants. Hence these methods open up new opportunities for further quantitative analysis of PCs and PC - metal complexes in cell culture and plant systems to understand the relationship between the biosynthesis of these compounds and metal tolerance.     

Robust profilometer for the measurement of 3-D object shapes based on a regularized phase tracker

A robust profilometer is proposed to measure 3-D object shapes based on a regularized phase tracker that is capable of demodulating fringe patterns with a high noise presence and broad bandwidth due to the object shape. As shown herein, the technique acts as an adaptive filter and is capable of giving the detected phase continuously so that no further unwrapping process is required. Experimental results of real surface profiles are presented.     

Probe efficiency improvement with remote and transmission line tuning and matching.

In certain nuclear magnetic resonance (NMR) applications in which accessibility to the gantry is limited, performing optimal tuning and matching represents a major problem. Here, we discuss a method of tuning NMR probe circuits and matching their impedances which uses cables with different impedance values. This simple but efficient method may be advantageous compared with much more difficult perfect tuning and matching.     

Cyclotron Production of 99Mo Radionuclide by Bombarding Zirconium Targets with Alpha Particle Beams

Russian Physics Journal - A possibility of manufacturing 99Mo via a nuclear reaction with 96Zr (α, n) in the R-7 cyclotron of the Tomsk polytechnic university is investigated. The beam energy...     

MCE‐electrochemical detection for following interactions of ssDNA and dsDNA with methylene blue

The interaction between the organic dye, methylene blue and DNA has been studied by MCE with electrochemical detection. Interaction produces two different signals, one corresponding to free methylene blue and other, for the complex methylene blue–DNA. The hybridization between a ssDNA and a complementary sequence, specific to the severe acute respiratory syndrome virus, has been performed and studied in a thermoplastic olefin polymer of amorphous structure CE‐microchip with an end‐channel gold wire detector. Moreover, studies with a longer dsDNA, an expression vector involved in the transitory or stable expression in mammals cells, pFLAG‐CMV4, has also been performed.     

Salt and solvent effects on the kinetics of the oxidation of the excited state of the [Ru(bpy)3]2+ complex by S2O8(2-)

The title reaction was studied in different reaction media: aqueous salt solutions (NaNO3) and water-cosolvent (methanol) mixtures. The observed rate constants, k(obs), show normal behavior in the solutions containing the electrolyte, that is, a negative salt effect. However, the solvent effect is abnormal, because a decrease of the rate constant is observed when the dielectric constant of the reaction medium decreases. These effects (the normal and the abnormal) can be explained using the Marcus-Hush treatment for electron transfer reactions. To apply this treatment, the true, unimolecular, electron-transfer rate constants, k(et), have been obtained from k(obs) after calculation of the rate constants corresponding to the formation of the encounter complex from the separate reactants, k(D), and the dissociation of this complex, k(-D). This calculation has been carried out using an exponential mean spherical approach (EMSA).     

The infrared spectrum of DCCF in the 320–850 cm−1 region: bending states up to υ4+υ5 = 3

Infrared spectra of deuterated monofluoroacetylene, DCCF, have been recorded in the region between 320 and 850 cm^?1 at an effective resolution ranging from 0.0024 to 0.0031 cm^?1. In total, 6650 rotation vibration transitions were assigned to 37 bands involving the bending states with v₄ + v₅ and |l₄+l₅|, respectively, up to 3, allowing the characterisation of the ground state and of 18 vibrationally excited states. The vν₅ bending fundamental has been studied for the first time. In addition, the difference band v₃ ← v₄ has been detected and analysed. All the assigned transitions have been fitted simultaneously by adopting a model Hamiltonian that takes into account the vibration and rotation l?type resonances. Rotational transitions in the ground and in bending excited states reported in the literature have been included in the global analysis. The set of 57 derived spectroscopic parameters reproduces 6130 infrared and 90 microwave and millimetre?wave transitions satisfactorily with root mean square values of 5.3 × 10^?4 cm^?1 and 77 kHz, respectively.     

Aromatic interactions impact ligand binding and function at serotonin 5-HT2C G protein-coupled receptors: receptor homology modelling,ligand docking,and molecular dynamics results validated by experimental studies

The serotonin (5-hydroxytryptamine, 5-HT) 5-HT₂ G protein-coupled receptor (GPCR) family consists of types 2A, 2B, and 2C that share ～75% transmembrane (TM) sequence identity. Agonists for 5-HT_2C receptors are under development for psychoses; whereas, at 5-HT_2A receptors, antipsychotic effects are associated with antagonists – in fact, 5-HT_2A agonists can cause hallucinations and 5-HT_2B agonists cause cardiotoxicity. It is known that 5-HT_2A TM6 residues W6.48, F6.51, and F6.52 impact ligand binding and function; however, ligand interactions with these residues at the 5-HT_2C receptor have not been reported. To predict and validate molecular determinants for 5-HT_2C-specific activation, results from receptor homology modelling, ligand docking, and molecular dynamics simulation studies were compared with experimental results for ligand binding and function at wild type and W6.48A, F6.51A, and F6.52A point-mutated 5-HT_2C receptors.     

Gut microbiota, diet, and heart disease

Modulation of the gut microbiota is an area of growing interest, particularly for its link to improving and maintaining the systemic health of the host. It has been suggested to have potential to reduce risk factors associated with chronic diseases, such as elevated cholesterol levels in coronary heart disease (CHD). Diets of our evolutionary ancestors were largely based on plant foods, high in dietary fiber and fermentable substrate, and our gut microbiota has evolved against a background of such diets. Therapeutic diets that mimic plant-based diets from the early phases of human evolution may result in drug-like cholesterol reductions. In contrast, typical Western diets low in dietary fiber and fermentable substrate, and high in saturated and trans fatty acids, are likely contributors to the increased need for pharmacological agents for cholesterol reduction. The gut microbiota of those consuming a Western diet are likely underutilized and depleted of metabolic fuels, resulting in a less than optimal gut microbial profile. As a result, this diet is mismatched to our archaic gut microbiota and, therefore, to our genome, which has changed relatively little since humans first appeared. While the exact mechanism by which the gut microbiota may modulate cholesterol levels still remains uncertain, end products of bacterial fermentation, particularly the short chain fatty acids (i.e., propionate), have been suggested as potential candidates. While more research is required to clarify the potential link between gut microbiota and CHD risk reduction, consuming a therapeutic diet rich in plant foods, dietary fiber, and fermentable substrate would be a useful strategy for improving systemic health, possibly by altering the gut microbiota.