Evidence of surface reconstructions and incorporation of oxygen into the oxide framework on the hydroxylated La2O3(001) surface

By performing first-principles Molecular Dynamics simulations at 300 K, we show that water dissociates on the A-La2O3(001) surface giving rise to one exclusive type of hydroxyl-group, which is associated with a surface reconstruction, incorporating an additional oxygen ion into the oxide subsurface, yielding a surface structure that is oxygen rich.     

Insights into UV-induced apoptosis: ultrastructure, trichrome stain and spectral imaging

Nuclear substructures associated with apoptosis in HeLa cells have been examined using light-microscopic morphometry, trichrome staining, spectral imaging and transmission electron microscopy. This detailed analysis reveals several sites where alterations in the normal cellular ultrastructure occur during apoptotic progression. To correlate these ultrastructural changes with the underlying molecular processes, we have characterized and quantified apoptotic cell morphology with and without inhibition of two caspases, which are key effectors of the apoptotic program. Using this analysis, early apoptotic events included: (a) the segregation of nucleolar components, a diminished granular component, and a reduction in number but increase in size of fibrillar centers, (b) an increase in the number of cytoplasmic ribosomes and (c) a very minimal increase in the amount of peripherally condensed DNA. Apoptosis progressed with: (a) an increase in the number of perichromatin granules and perichromatin fibrils, (b) a reduction in number of interchromatin granule centers concomitant with an increase in their size, (c) partial digestion and circumferential condensation of the DNA at the nuclear membrane and (d) rounding of the cytoplasm with an increase in organellar density and shrinkage in cell size. Endstage apoptotic cells showed: (a) one (or two) very large pools of incompletely digested DNA, (b) one (or two) very large interchromatin granule centers, (c) an increased number of perichromatin granules which were distanced from DNA and often closely apposed to the nucleolus, (d) formation of unusually condensed, highly coiled perinucleolar bodies and (e) blebbing of highly dense cytoplasm.In HeLa cells treated with UV and inhibitors of caspase 1 and 3, the length of time from early apoptosis to the formation of apoptotic bodies was greatly extended. Inhibiting caspase activity: (a) prevented the pooling of DNA, (b) retarded the formation of large interchromatin granule centers, (c) increased the number of perichromatin granules, (d) produced disassembly of the nucleolus, (e) prevented the formation of highly coiled perinucleolar bodies, and (f) caused vacuolization in the cell center and a unipolar blebbing of the cytoplasm.Spectral imaging in conjunction with serial section electron microscopy confirmed the staining specificities of the condensed DNA, of the large condensed interchromatin granule centers, and of the nucleoli. The results indicate that the interface between the components of the chromatin domain and the interchromatin space is a critical site of caspase activity in apoptosis, and precedes other events such as internucleosomal DNA degradation.     

The Effect of Blood Contained in the Samples on the Metabolomic Profile of Mouse Brain Tissue: A Study by NMR Spectroscopy

(1) Recently, metabolic profiling of the tissue in the native state or extracts of its metabolites has become increasingly important in the field of metabolomics. An important factor, in this case, is the presence of blood in a tissue sample, which can potentially lead to a change in the concentration of tissue metabolites and, as a result, distortion of experimental data and their interpretation. (2) In this paper, the metabolomic profiling based on NMR spectroscopy was performed to determine the effect of blood contained in the studied samples of brain tissue on their metabolomic profile. We used 13 male laboratory CD-1^® IGS mice for this study. The animals were divided into two groups. The first group of animals (n = 7) was subjected to the perfusion procedure, and the second group of animals (n = 6) was not perfused. The brain tissues of the animals were homogenized, and the metabolite fraction was extracted with a water/methanol/chloroform solution. Samples were studied by high-frequency ¹H-NMR spectroscopy with subsequent statistical data analysis. The group comparison was performed with the use of the Student’s test. We identified 36 metabolites in the brain tissue with the use of NMR spectroscopy. (3) For the major set of studied metabolites, no significant differences were found in the brain tissue metabolite concentrations in the native state and after the blood removal procedure. (4) Thus, it was shown that the presence of blood does not have a significant effect on the metabolomic profile of the brain in animals without pathologies.     

New indoline spiropyrans with highly stable merocyanine forms

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A novel convenient synthesis of 5-acyl-1,2-dihydropyrimidin-2-ones via 4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones

A novel four-step methodology for the synthesis of 5-acyl-1,2-dihydropyrimidin-2-ones has been developed. The reaction of readily available N-[(1-acetoxy-2,2,2-trichloro)ethyl]ureas with Na-enolates of 1,3-diketones or β-oxoesters followed by heterocyclization-dehydration of the oxoalkylureas formed gave 5-acyl-4-trichloromethyl-1,2,3,4-tetrahydropyrimidin-2-ones. The latter, in the presence of NaH, eliminate CHCl₃ to give the target compounds.     

Development of a Xanthine Oxidase Modified Amperometric Electrode for the Determination of the Antioxidant Capacity

This paper describes the development of a xanthine oxidase/poly‐m‐phenylenediamine (XOD‐PPD)‐modified electrode. The biosensor was constructed by encapsulating XOD in a sol‐gel matrix deposited onto a platinum based screen‐printed electrode functionalized with a permselective PPD membrane. The hydrogen peroxide generated as a final product of the enzymatic reaction between the hypoxanthine and the XOD or by the spontaneous dismutation of superoxide radicals was selectively monitored at +700 mV. The use of a highly selective PPD layer blocked the nonspecific oxidation of other oxidizable molecules. Finally the biosensor was applied to the determination of the antioxidant capacity of acetylsalicylic acid.