A bioinspired look at the glucosinolate metabolic pathway. Structural insights into the reaction of benzyl isothiocyanate and d-glucosamine

Through a well-established enzymatic transformation glucosinolates release reactive isothiocyanates that can undergo further metabolic pathways affording a plethora of reactive metabolites. This study explores in detail the reaction of benzyl isothiocyanate, which possesses antitumor activity as alkylating agent, with d-glucosamine, commonly employed in oral treatments against osteoarthritis and inflammation. Structures of the resulting products and their evolution have been assessed and compared with those involving d-glucose, reported previously. Chemical results suggest that clinical treatments with d-glucosamine could reduce the beneficial effects associated with diets based on glucosinolate-rich foods.     

Metabolomic analysis characterizes tissue specific indomethacin-induced metabolic perturbations of rats

In this study, the promising metabolomic approach integrating with ingenuity pathway analysis (IPA) was applied to characterize the tissue specific metabolic perturbation of rats that was induced by indomethacin. The selective pattern recognition analyses were applied to analyze global metabolic profiling of urine of rats treated by indomethacin at an acute dosage of reference that has been proven to induce tissue disorders in rats, evaluated throughout the time-course of -24-72 h. The results preliminarily revealed that modifications of amino acid metabolism, fatty acid metabolism and energetically associated metabolic pathways accounted for metabolic perturbation of the rats that was induced by indomethacin. Furthermore, IPA was applied to deeply analyze the biomarkers and their relations with the metabolic perturbations evidenced by pattern recognition analyses. Specific biochemical functions affected by indomethacin suggested that there is an important correlation of its effects in kidney and liver metabolism, based on the determined metabolites and their pathway-based analysis. The IPA correlation of the three major biomarkers, identified as creatinine, prostaglandin E2 and guanosine, suggested that the administration of indomethacin induced certain levels of toxicity in the kidneys and liver. The changes in the levels of biomarker metabolites allowed the phenotypical determination of the metabolic perturbations induced by indomethacin in a time-dependent manner.     

Hetero-Diels-Alder reaction of phosphinyl and phosphonyl nitroso alkenes with conjugated dienes: an aza-Cope rearrangement

Phosphorylated nitroso alkenes react with cyclic dienes such as cyclopentadiene or cyclohexadiene to afford hetero Diels-Alder-type cycloadducts where the nitroso alkene participates as dienophile component and the cyclic olefin acts as the 4π-electron (diene) system. Subsequent aza-Cope rearrangement affords highly functionalized 5,6-dihydro-4H-1,2-oxazines. Conversely, the reaction of TMS-substituted cyclopentadiene (dienophile) with nitroso alkenes as heterodienes leads directly to bicyclic 1,2-oxazines. Theoretical studies are in agreement with the experimental results and with the new aza-Cope rearrangement proposed.     

Vibrational spectra of double oxalates of the type M(I)2Cu(C2O4)(2)·2H2O (MI=Na+, K+, NH4+)

The infrared and Raman spectra of Na2Cu(C2O4)(2)·2H2O, K2Cu(C2O4)(2)·2H2O and (NH4)2Cu(C2O4)(2)·2H2O were recorded and briefly discussed on the basis of their structural peculiarities and by comparison with the vibrational spectra of other metallic oxalates.     

Probing vibrational wave packets in molecular excited states

A time-dependent theoretical method is used to describe a UV pump?CUV probe strategy to trace, at a femtosecond time scale, the motion of vibrational wave packets created in excited states of the hydrogen molecule by measuring single ionization probabilities. We use a spectral method to solve the time-dependent Schr?dinger equation in full dimensionality, including correlation and all electronic and vibrational degrees of freedom. A pump pulse initially creates a vibrational wave packet in the intermediate electronic excited states of $\hbox{H}_2$ . The frequency of the probe is chosen to ionize the target leaving the ion in a bound vibrational state. By varying the time delay between pulses, non-dissociative single ionization is enhanced or suppressed. Energy differential ionization probabilities are reported and compared with a model based on the Franck?CCondon approximation.     

On the stability and lifetime of GaO2+ in the gas phase

The electronic structure, stability, and lifetime of GaO²⁺ have been investigated using high-level ab initio calculations. The potential energy curves have been calculated at the CCSD(T)/aug-cc-pV5Z and at the MS-CASPT2/ANO-RCC levels of theory. Lifetimes were evaluated using the Exterior Complex Scaling (ECS) method and B-spline basis functions. Our calculations show that GaO²⁺ is a metastable species in the gas phase, since the diatomic dication, in its ground state, lies 97.1?kcal/mol above the Ga⁺ (¹S)?+?O⁺ (⁴S) dissociation limit. However, the energy barrier that has to be overcome to reach this limit is 3?kcal/mol high so that five vibrational resonances can be accommodated between the bottom of the well and the top of the barrier. The evaluated lifetimes vary from hundreds of femtoseconds to approximately 1?s, so at least two of them have long enough lifetimes (1?s and 91???s) to be detected using mass spectrometry techniques, in agreement with the experimental evidence. In the experiment (Fiser et al. in Eur J Mass Spectrom 15:315?C324, 2009), GaO²⁺ was observed for an ion flight time of about ~12???s through a magnetic-sector mass spectrometer and unambiguously identified by its isotopic abundance. Our results also show that isotopic effects on the resonances?? energies and on their lifetimes, when ⁷⁰Ga is replaced by ⁶⁹Ga or ⁷¹Ga, are very small (~0.1 and ~1%, respectively), reflecting the large mass of the system.     

On real forms of JB*-triples

We introduce real JB^*-triples as real forms of (complex) JB^*-triples and give an algebraic characterization of surjective linear isometries between them. As main result we show: A bijective (not necessarily continuous) linear mapping between two real JB^*-triples is an isometry if and only if it commutes with the cube mappinga→a ³={aaa}. This generalizes a result of Dang for complex JB^*-triples. We also associate to every tripotent (i.e. fixed point of the cube mapping) and hence in particular to every extreme point of the unit ball in a real JB^*-triple numerical invariants that are respected by surjective linear isometries.     

Mössbauer spectroscopic and SEM study of Campanian and Terra sigillata pottery from Spain

A combination of Mössbauer spectroscopy (CEMS and transmission) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) was employed to study the differences between coat and body in Campanian and Terra Sigillata wares. Conclusions about type of clay, origin of colour, and fabric and firing technology are established.