C-H. . .pi interactions in the metal-porphyrin complexes with chelate ring as the H acceptor

Specific C-H. . .pi interactions with the pi-system of porphyrinato chelate ring were found in crystal structures of transition metal complexes from the Cambridge Structural Database and statistical analysis of geometrical parameters for intramolecular and intermolecular interactions was done. By density functional theory calculations on a model system it was evaluated that an interaction energy is above 1.5 kcal/mol and that the strongest interaction occurs when the distance between hydrogen atom and the center of the chelate ring is 2.6 A. This prediction is in good agreement with the distances for intermolecular interactions found in the crystal structures. In many cases the intramolecular interaction distances are much shorter than 2.6 A, and these short distances are caused by geometrical constrains. The C-H. . .pi interactions with chelate ring of porphyrinato ligand can influence the structure, contribute to its stability, and play some role in the function of biomolecules with metalo porphyrins.     

Ribo-, xylo-, and arabino-configured adenine-based nucleoside phosphonates: synthesis of monomers for solid-phase oligonucleotide assembly

Adenine-based, regioisomeric nucleoside phosphonates with ribo, xylo and arabino configuration were synthesized in the protected form suitable for the phosphotriester-like, solid-phase synthesis of oligonucleotides. Phosphonate moiety was protected by 4-methoxy-1-oxido-2-picolyl group and the furanose hydroxyl by the dimethoxytrityl group.     

Standard anthropometric, body composition, and strength variables as predictors of jumping performance in elite junior athletes

The aim of the study was to investigate whether variables routinely assessed while testing athletes can also predict movement performance. The relation between jumping performance and standard strength, anthropometric, and body composition variables was examined in elite junior basketball players. The 33 males were tested for maximal vertical jump, as well as for maximal isometric voluntary force and rate of force development of hip and knee extensors. Standard anthropometric and body composition measures (body height, lean body mass, as well as the percentage of fat and muscle tissue) were also taken. Except for maximal isometric forces (0.38 and 0.52 N.kg(-1) for hip and knee extensors, respectively), all correlation coefficients between the selected variables and jump height were insignificant. As a consequence, the corresponding multiple correlation coefficient, R = 0.71, also suggested a moderate predictability of jumping performance by the standard strength tests and anthropometric and body composition variables. The results obtained dispute the use of the examined tests in sport performance assessment, and also question applying the tests for other purposes such as evaluation of training procedures or selection of young athletes. Therefore, the results are in line with the concept that a reliable performance assessment in homogeneous groups of athletes requires predominantly movement-specific testing.     

Analysis of cysteine and N-acetylcysteine in human plasma by high-performance liquid chromatography at the basal state and after oral administration of N-acetylcysteine

A high-performance liquid chromatographic method for the determination of free reduced cysteine and N-acetylcysteine in human plasma at the basal state and after oral administration of N-acetylcysteine is described. The method is based on acid-catalysed conversion of plasma thiols to the corresponding S-nitroso derivatives by excess of nitrite and their subsequent cation-pairing RP-HPLC with detection at 333 nm. Recovery rates of cysteine and N-acetylcysteine added to human plasma were 94.6 and 99.6%, respectively. Inter- and intra-day precision were below 6%. In healthy humans (n=5), free reduced cysteine was determined to be (mean±S.E.) 10.0±0.96 μM. No N-acetylcysteine was detected in plasma of these subjects above the limit of detection (e.g. 170 nM). The method was successfully applied to a pharmacokinetic study on orally administered N-acetylcysteine to healthy volunteers.     

Changing complexity of endogenous lectin activities during juvenile development of Xenopus laevis

Galactoside-binding lectin has been isolated from whole Xenopus laevis embryos and tadpoles at four development stages: st. 24–26, 32, 41 and 47. The main lectin activity at st. 24–26 is -galactoside specific, producing a 34/35.5K doublet on SDS-PAGE. Later in development, lectin activities specific for a wide range of other sugars appear concommitant with the detection of a number of new protein bands on SDS-PAGE gels. The greatest variety of new lectin activities exists at st. 32 when lectins specific for all of the main sugar families found in nature are detected. After this stage and up to st. 47 (the beginning of metamorphosis), fewer different lectin activities are again detected. The results suggest that a complex, developmentally regulated battery of different lectins are present during early Xenopus development, perhaps with stage-specific roles to play in the control of tissue morphogenesis.     

Stabilized Romanowsky Blood Stain

It has been down that the degradation of thiazine dyes which normally occurs in methanolic solution, as in the case of Romanowsky blood stains, can be prevented by nuking the solution acidic. In a certain range of oddity, the stain precipitates in the form of monothiazine cosinate, but by making the solution sufficiently acidic, eosin is protonated and the precipitate cannot form. These observations have been used to develop a blood stain which is stable, even at elevated temperatures, for sexed months. For use the stain is neutralized by a specially formulated fixative solution.     

Distribution of a galactose-specific lectin in endoderm cells from early chick embryos

Summary Cells from the endoderm of the area opaca of gastrulating chick embryos were maintained in stationary cultures, stained with antibodies against the endogenous -D-galactoside-binding lectin and examined by immuno-fluorescence. In the majority of cells fluorescence was present as an irregular circular web in the central cytoplasm. In cells that appeared to be migrating increased fluorescence was observed in the peripheral cytoplasm and retraction fibers. In regions where a portion of the cell was detaching from the substratum high fluorescence was observed in the extracellular footprints deposited by the cell.     

Songbird chemosignals: volatile compounds in preen gland secretions vary among individuals, sexes, and populations

Chemical signaling has been documented in many animals, but its potential importance in avian species, particularly songbirds, has received far less attention. We tested whether volatile compounds in the preen oil of a songbird (Junco hyemalis) contain reliable information about individual identity, sex, or population of origin by repeated sampling from captive male and female juncos originating from 2 recently diverged junco populations in southern California. One of the populations recently colonized an urban environment; the other resides in a species-typical montane environment. The birds were field-caught as juveniles, housed under identical conditions, and fed the same diet for 10 months prior to sampling. We used capillary gas chromatography-mass spectrometry to quantify the relative abundance of 19 volatile compounds previously shown to vary seasonally in this species. We found individual repeatability as well as significant sex and population differences in volatile profiles. The persistence of population differences in a common environment suggests that preen oil chemistry likely has a genetic basis and may thus evolve rapidly in response to environmental change. These finding suggest that songbird preen oil odors have the potential to function as chemosignals associated with mate recognition or reproductive isolation.     

A proteomic survey of rat cerebral cortical synaptosomes

Previous findings from our laboratory and others indicate that two-dimensional gel electrophoresis (2-DE) can be used to study protein expression in defined brain regions, but mainly the proteins which are present in high abundance in glia are readily detected. The current study was undertaken to determine the protein profile in a synaptosomal subcellular fraction isolated from the cerebral cortex of the rat. Both 2-DE and liquid chromatography - tandem mass spectrometry (LC-MS/MS) procedures were used to isolate and identify proteins in the synaptosomal fraction and accordingly >900 proteins were detected using 2-DE; the 167 most intense gel spots were isolated and identified with matrix-assisted laser desorption/ionization - time of flight peptide mass fingerprinting or LC-MS/MS. In addition, over 200 proteins were separated and identified with the LC-MS/MS "shotgun proteomics" technique, some in post-translationally modified form. The following classes of proteins associated with synaptic function were detected: (a) proteins involved in synaptic vesicle trafficking-docking (e.g., SNAP-25, synapsin I and II, synaptotagmin I, II, and V, VAMP-2, syntaxin 1A and 1B, etc.); (b) proteins that function as transporters or receptors (e.g., excitatory amino acid transporters 1 and 2, GABA transporter 1); (c) proteins that are associated with the synaptic plasma membrane (e.g., post-synaptic density-95/synapse-associated protein-90 complex, neuromodulin (GAP-43), voltage-dependent anion-selective channel protein (VDACs), sodium-potassium ATPase subunits, alpha 2 spectrin, septin 7, etc.); and (d) proteins that mediate intracellular signaling cascades that modulate synaptic function (e.g., calmodulin, calcium-calmodulin-dependent protein kinase subunits, etc.). Other identified proteins are associated with mitochondrial or general cytosolic function. Of the two proteins identified as endoplasmic reticular, both interact with the synaptic SNARE complex to regulate vesicle trafficking. Taken together, these results suggest that the integrity of the synaptosomes was maintained during the isolation procedure and that this subcellular fractionation technique enables the enrichment of proteins associated with synaptic function. The results also suggest that this experimental approach can be used to study the differential expression of multiple proteins involved in alterations of synaptic function.     

Oxygen radicals produced by plant plasma membranes: an EPR spin-trap study

Plant plasma membranes are known to produce superoxide radicals, while the production of the hydroxyl radical, previously detected in complex plant tissues, is thought to occur in the cell wall. The mechanism of production of superoxide radicals by plant plasma membranes is, however, under dispute. It is shown, using electron paramagnetic resonance spectroscopy with a 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide spin-trap capable of differentiating between radical species, that isolated purified plasma membranes from maize roots produce hydroxyl radicals besides superoxide radicals. The results argue in favour of superoxide production through an oxygen and diphenylene iodonium-sensitive, NADH-dependent superoxide synthase mechanism, as well as through other unidentified mechanism(s). The hydroxyl radical is produced by an oxygen-insensitive, NADH-stimulated mechanism, which is enhanced in membranes in which the superoxide synthase is incapacitated by substrate removal or inhibition.