Differential expression of Cathepsin S and X in the spinal cord of a rat neuropathic pain model

Background

Proteoglycan (PG) in the extracellular matrix (ECM) of the central nervous system (CNS) may act as a barrier for neurite elongation in a growth tract, and regulate other characteristics collectively defined as structural neural plasticity. Proteolytic cleavage of PGs appears to alter the environment to one favoring plasticity and growth. Brevican belongs to the lectican family of aggregating, chondroitin sulfate (CS)-bearing PGs, and it modulates neurite outgrowth and synaptogenesis. Several ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) are glutamyl-endopeptidases that proteolytically cleave brevican. The purpose of this study was to localize regions of adult CNS that contain a proteolytic-derived fragment of brevican which bears the ADAMTS-cleaved neoepitope sequence. These regions were compared to areas of Wisteria floribunda agglutin (WFA) reactivity, a common reagent used to detect "perineuronal nets" (PNNs) of intact matrix and a marker which is thought to label regions of relative neural stability.

Results

WFA reactivity was found primarily as PNNs, whereas brevican and the ADAMTS-cleaved fragment of brevican were more broadly distributed in neuropil, and in particular regions localized to PNNs. One example is hippocampus where the ADAMTS-cleaved brevican fragment is found surrounding pyramidal neurons, in neuropil of stratum oriens/radiatum and the lacunosum moleculare. The fragment was less abundant in the molecular layer of the dentate gyrus. Mostly PNNs of scattered interneurons along the pyramidal layer were identified by WFA. In lateral thalamus, the reticular thalamic nucleus stained abundantly with WFA whereas ventral posterior nuclei were markedly immunopositive for ADAMTS-cleaved brevican. Using Western blotting techniques, no common species were reactive for brevican and WFA.

Conclusion

In general, a marked discordance was observed in the regional localization between WFA and brevican or the ADAMTS-derived N-terminal fragment of brevican. Functionally, this difference may correspond to regions with varied prevalence for neural stability/plasticity.     

Refinement of the 3/2 power law and radial drift theory of the ion current to a small probe or a dust particle in a rarified plasma

The ion current to a probe or a dust particle in a rarified plasma is considered in terms of the plasma sheath theory and the radial drift theory. The effect of the initial directed velocity of ions entering the sheath in accordance with the Bohm criterion on the current-voltage characteristic of the space charge sheath is studied. Computations based on both theories are performed for the extended range of the relative values of probes (0.0001?C20.0) r _p /??_D, where r _p is the size of the probe and ??_D is the electron Debye radius. The two theories are compared in the entire design range of the sizes of probes. Analytical approximations are given for practical application of the results.     

Determination of the Constants of Binding of Acridine Dyes with Micelles of Sodium Dodecyl Sulfate Using the Quenching of Delayed Fluorescence by Heavy Atoms

The constants of binding dye molecules with the micelles of sodium dodecyl sulfate are determined using quenching of delayed fluorescence of acridine dyes by sodium iodide in aqueous–micellar solutions. Kinetic equations have been composed that describe the processes of deactivation of the excited states of dyes. By solving these equations at the concentration of the quencher sodium iodide corresponding to the minimum lifetime of triplet states and at the concentration of micelles corresponding to the least value of the delayed fluorescence quenching rate constants, we obtained the constants of binding dyes with micelles equal to 1.3·10⁷, 2.9·10⁷, and 3.1·10⁷ M^–1 for trypaflavine, acridine orange, and acridine yellow, respectively. We calculated the rate constants of quenching of the triplet states of the molecules of dyes by iodide ions (I ^–) that decreased in transition from trypaflavine to acridine orange and acridine yellow.     

Modification of surface properties of electrospun polyamide nanofibers by means of a perfluorinated acridine

Polyamide 6 (PA6) nanofibers were prepared from formic acid solutions by using electrospinning technique. The fibers were smooth, defects free and with diameters smaller than 200 nm. Small amounts of a perfluorinated acridine were added as dopant to the feed solution to modify the wettability of the fibers. The effect of doping on the contact angle values is well apparent. The contact angle values go from 50° of pure PA6 to 120° when 6% of acridine is added. A comparison between fibers and films of pure and doped polyamide 6 was carried out in order to determine the effect of morphology on wettability. Thermal annealing near the T_g of the polymer promoted the segregation of the molecules to the surface, reaching contact angles of 131° with smaller amounts (4%) of acridine. The surface segregation was also promoted by time aging.     

Positions of the Glycans in Molluscan Hemocyanin, Determined by Fluorescence Spectroscopy

Molluscan hemocyanins are glycoproteins with different quaternary and carbohydrate structures. It was suggested that the carbohydrate chains of some Hcs are involved in their antiviral and antitumor effect, as well in the organization of the quaternary structure of the molecules. Using a well-known complex for saccharide sensing, positions and access to the carbohydrate chains in the native hemocyanins from Rapana venosa (RvH) and Helix lucorum (HlH) and also their structural subunits (RvH1, RvH2 and β_cHlH) and functional units (FUs) were analysed by fluorescence spectroscopy and circular dichroism. Almost no effect was observed in the fluorescence emission after titration of the complex with native RvH and HlH due to lack of free hydroxyl groups which are buried in the didecameric form of the molecules. Titration with the structural subunits β_cHlH and RvH2, increasing of the emission indicates the presence of free hydroxyl groups compared to the native molecules. Complex titration with the structural subunit βc-HlH of H. lucorum Hcs leads to a 2.5 fold increase in fluorescence intensity. However, the highest emission was measured after titration of the complex with FU βcHlH-g. The result was explained by the structural model of β_cHlH-g showing the putative position of the glycans on the surface of the molecule. The results of the fluorescent measurements are in good correlation with those of the circular dichroism data, applied to analyse the effect of titration on the secondary structure of the native molecules and functional units. The results also support our previously made suggestion that the N-linked oligosaccharide trees are involved in the quaternary organization of molluscan Hcs.     

Evidence for proteolytic cleavage of brevican by the ADAMTSs in the dentate gyrus after excitotoxic lesion of the mouse entorhinal cortex

Background  

Brevican is a member of the lectican family of aggregating extracellular matrix (ECM) proteoglycans that bear chondroitin sulfate (CS) chains. It is highly expressed in the central nervous system (CNS) and is thought to stabilize synapses and inhibit neural plasticity and as such, neuritic or synaptic remodeling would be less likely to occur in regions with intact and abundant, lectican-containing, ECM complexes. Neural plasticity may occur more readily when these ECM complexes are broken down by endogenous proteases, the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs), that selectively cleave the lecticans. The purpose of these experiments was to determine whether the production of brevican or the ADAMTS-cleaved fragments of brevican were altered after deafferentation and reinnervation of the dentate gyrus via entorhinal cortex lesion (ECL).     

Complexation of heterocyclic ligands with DNA in aqueous solution

We have used spectrophotometry to study self-association and complexation with DNA by organic heterocyclic compounds in the acridine and phenothiazine series: proflavin, thionine, and methylene blue. Based on the experimental concentration dependences of the molar absorption coefficient of the molecules in an aqueous buffer solution (0.01 M NaCl, 0.01 M Na₂EDTA, 0.01 M Tris, pH 7.4, T = 298 K), we have determined the equilibrium dimerization constants for the dyes and the DNA complexation parameters using the Scatchard and McGhee-von Hippel models. The observed increase in the cooperativity parameters as the dimerization constants of the ligands increase allowed us to hypothesize that the same interactions occur between dye molecules adsorbed on DNA as in their self-association. The equilibrium DNA-binding constants for the ligands, obtained using the McGhee-von Hippel cooperative model, are (20.9 ± 2.7)·10³ M⁻¹ for proflavin and (33.8 ± 4.1)·10³ M⁻¹ for thionine. Using the Scatchard model, taking into account intercalation and “external” binding of ligands with DNA, we determined the DNA complexation constants for methylene blue: (26.4 ± 4.6)·10³ and (96 ± 17)·10³ M⁻¹ respectively. Based on analysis of the data obtained, we hypothesized that the predominant type of binding with DNA is intercalation binding in the case of proflavin and thionine, and “external” binding with the DNA surface in the case of methylene blue. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 242–249, March–April, 2008.     

Role of nonlocal ionization in formation of the short glow discharge

An analytical model for estimating basic characteristics of short (without a positive column) glow discharges is suggested that allows for electron generation both in the cathode sheath and by nonlocal ionization in the plasma negative glow. The model is based on a previously developed approach according to which the discharge gap is divided into space-charge layers and a quasi-neutral plasma. The plasma region includes part of the negative glow, Faraday dark space, and positive column (if it exists). Simple expressions for basic characteristics of the glow discharge (I–V characteristic, cathode sheath thickness, position of the point of electric field reversal, etc.) are derived, and plasma concentration distributions are presented. The results obtained in terms of our model are in good agreement with experimental data, while local approximations based on the classical Engel-Steenbeck model diverge considerably from the experiment.     

Crystal structure of ethyl pyruvate-2-methyl-4-chloro-phenyl hydrazone

Ethyl pyruvate-2-methyl-4-chloro-phenylhydrazone, C₁₂H₁₅N₂O₂Cl, is an important intermediate for the synthesis of ethyl-5-chloro-7-methyl indole-2-carboxy-late. Crystals are orthorhombic witha=6.99(4),b=23.75(6),c=17.05(6) Å and eight molecules per cell in the space group Cmca. The structure was solved by direct methods using film data and refined by block diagonal least squares method to anR-index of 0.052. The molecule occupies the space group mirror(m) special position. The stacking of the molecules is stabilized by van der Waal’s contacts.     

The interaction between polyelectrolyte microgels of <Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide copolymers and aqueous solutions of alcian blue

The temperature influence on the behavior of microgels based on poly-N-isopropylacrylamide (PNIPA) homopolymer, N-isopropylacrylamide copolymers with sodium methacrylate (PNIPA/MANa), sodium styrenesulfonate (PNIPA/SSNa), and sodium vinylsulfonate (PNIPA/VSNa) was studied. The comparative analysis of the temperature-induced collapse of macro- and microgels was conducted. The interaction between alcian blue and PNIPA, PNIPA/SSNa, PNIPA/VSNa, and PNIPA/MANa gels was studied. The research showed that dye sorption leads to the contraction of oppositely charged microgels. The sorption effectiveness depends on the nature of the ionogenic units. The dye sorption by PNIPA/SSNa microgels is more effective than the sorption by the corresponding macrogels. The AB sorption by PNIPA/MANa microgels is less than the sorption by the corresponding macrogels and by the PNIPA/SSNa microgels. The interaction properties are connected to the structure of the crosslinked polymer chains in the microgels.     

Tunable spectral switching in the far field with a chirped cosh-Gaussian pulse

We have shown the possibility of tunable spectral switching in the far field with an apertured chirped cosh-Gaussian pulse by varying its cosh parameter (Ω). We have also shown that the switching frequency and both blue and red shifted frequencies can be also tuned by varying Ω. Possible application of our results in optical space communications has been highlighted.     

Chondroitin sulfate proteoglycans regulate the growth, differentiation and migration of multipotent neural precursor cells through the integrin signaling pathway

Background  

Neural precursor cells (NPCs) are defined by their ability to proliferate, self-renew, and retain the potential to differentiate into neurons and glia. Deciphering the factors that regulate their behaviors will greatly aid in their use as potential therapeutic agents or targets. Chondroitin sulfate proteoglycans (CSPGs) are prominent components of the extracellular matrix (ECM) in the central nervous system (CNS) and are assumed to play important roles in controlling neuronal differentiation and development.     

Electronic spectra of XeNe molecules in the range 77100-90100 cm-1 near Xe* (6p, 5d, 6p’, 7s, 7p, 6d) obtained by the (3 + 1) REMPI and (2 + 1) REMPI methods

The electronic spectra of XeNe molecules in the range of 77100-90100 cm^-1 are measured by the method of laser resonance multiphoton ionization in a supersonic jet. The photoionization spectra are obtained upon two- and three-photon excitations of molecules and their ionization by the next photon. In the range of 80300-90100 cm^-1 near Xe*(5d, 6p’, 6d, 7s, and 7p), the spectra are obtained for the first time. A whole number of vibrational systems are measured in this range. The majority of vibrational systems near Xe* (5d, 6d, 7p, and 7s) are located in the red range with respect to their dissociation limits. In the blue range with respect to the dissociation limits, continua corresponding to transitions of molecules from the ground state to repulsive potential curves of excited states are detected. For a number of excited states of XeNe molecules, the vibrational analysis is performed and molecular constants are estimated.     

A novel three-dimensional system to study interactions between endothelial cells and neural cells of the developing central nervous system

Background  

During angiogenesis in the developing central nervous system (CNS), endothelial cells (EC) detach from blood vessels growing on the brain surface, and migrate into the expanding brain parenchyma. Brain angiogenesis is regulated by growth factors and extracellular matrix (ECM) proteins secreted by cells of the developing CNS. In addition, recent evidence suggests that EC play an important role in establishing the neural stem cell (NSC) niche. Therefore, two-way communication between EC and neural cells is of fundamental importance in the developing CNS. To study the interactions between brain EC and neural cells of the developing CNS, a novel three-dimensional (3-D) murine co-culture system was developed. Fluorescent-labelled brain EC were seeded onto neurospheres; floating cellular aggregates that contain NSC/neural precursor cells (NPC) and smaller numbers of differentiated cells. Using this system, brain EC attachment, survival and migration into neurospheres was evaluated and the role of integrins in mediating the early adhesive events addressed.     

Intercalation of aminonaphthalenes into α-zirconium hydrogenphosphate

Intercalates of 1- and 2-aminonaphthalene (1-AN and 2-AN), 1,5- and 1,8-diaminonaphthalene (1,8-DAN) and 2-aminoanthracene (2-AA) into α-Zr(HPO₄)₂·H₂O were prepared and characterized by powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. As follows from IR, molecules of aminonaphthalenes are protonated in the interlayer space. 1,5-diaminonaphthalene (1,5-DAN) molecules are arranged in a monomolecular way in the intercalate. The other guest molecules form partially interdigitated bilayers in the interlayer space.     

Spectroscopic analyses on interaction of bovine serum albumin (BSA) with toluidine blue (TB) and its sonodynamic damage under ultrasonic irradiation

In this paper, the toluidine blue (TB) with tricyclic quinone imide plane structure is used as sonosensitizer to study the interaction and sonodynamic damage to bovine serum albumin (BSA) by UV-vis and fluorescence spectroscopy. The results show that the TB can bind to BSA molecules, obviously, and the synergetic effects of TB and ultrasonic irradiation can efficiently damage the BSA molecules. Otherwise, some influencing factors such as ultrasonic irradiation time, TB concentration, pH value and ionic strength on the damage of BSA molecules were also considered by the numbers. Synchronous fluorescence spectroscopy indicates that the tyrosine (Tyr) residues of BSA molecules are damaged more seriously than the tryptophan (Trp) residues under ultrasonic irradiation.     

Crystal structure of BaCa2MgSi2O8 and the photoluminescent properties activated by Eu

Rietveld refinements of X-ray powder diffraction data have confirmed the crystal structure of BaCa₂MgSi₂O₈ prepared by a standard solid-state method. The final reliable factors were R_wp=10.91%, R_p=8.10%, R_I=2.71%, and R_F=1.14%. BaCa₂MgSi₂O₈ crystallizes in the trigonal space group P3¯m1 (no. 164) with a=5.430(3) Å and c=6.807(2) Å. The oxide has a layered structure constructed from the unit layers built up by corner-sharing MgO₆ octahedra and SiO₄ tetrahedra. Ba and Ca atoms occupy the distinct crystallographic sites; Ba atom is sited in the interlayer space and Ca atom is embedded in the layer framework. This structure was not disrupted by doping of Eu²⁺ ions.The Eu²⁺-doped BaCa₂MgSi₂O₈ exhibited an intense blue emission based on 5d-4f electron transitions of Eu²⁺ ions under 254 nm excitation. This emission has a sufficient chromaticity as a blue phosphor. An additional analysis of the emission spectra using an empirical formula indicates that Eu²⁺ is distributed into both Ba and Ca sites.     

Cortical diversity in three species groups of Parmotrema sensu lato (Parmeliaceae,lichenized Ascomycota)

Conventional techniques for structural studies under light microscope were employed to describe and compare the upper cortex anatomy in three species groups of Parmotrema sensu lato. This study indicates that there is a pattern in the structure of the upper cortex in all the three groups of Parmotrema species studied here, and this pattern can be used to place each species group separately within the genus Parmotrema. Although the species of Parmotrema studied have palisade prosoplectenchymatous upper cortex, there are clear differences between the analyzed groups. The upper cortex of Parmotrema s. str. can be characterized by more elongated cells and very compressed hyphae with small interstices between them; the upper cortex of the species with reticular maculae is characterized by the presence of maculae produced by the organization of hyphae that rise towards to the upper cortex and that are not so compressed, while the upper cortex of the species with dimorphic rhizinae has less elongated almost-rounded cells without interstices or cracks but is generally accompanied by aeroplectenchyma. Besides, the first cell layer of the upper cortex presents differential staining by toluidine blue and the epicortex is tightly attached to it.     

Diffusion of overdamped classical solitons

We study the diffusion and deformation of classical solitons coupled to thermal noise. The diffusion coefficient for kinds in the gf⁴ theory is predicted up to the second order in kT. The prediction is verified by numerical simulations. Multiskyrmions in the vector O(3) sigma model are studied within the same formalism. Thermal noise results in a diffusion on the multisoliton collective coordinate space (moduli space). There are entropic forces which tend, for example, to bind pairs of solitons into bi-solitonic molecules.     

On the centrifugal distortion in the microwave spectra of O2 and SO

Stable radicals formed by room temperature X-irradiation of single crystals of acridine and phenazine have been identified and their structures determined by detailed ENDOR studies at 77 K. The E.S.R. spectra are of little assistance in the identification of these radicals. However, the high resolution of ENDOR has made it possible to study all the proton hyperfine interactions in detail. The radicals investigated in this study are formed as a result of the addition of atomic hydrogen to the nitrogen atom of the acridine and phenazine molecules. ENDOR lines of all the protons have been identified and analysed. Spin densities have been deduced from the proton hyperfine tensors. Although the unpaired electron is extensively delocalized throughout the molecule, there are large spin densities (0·475 and 0·584, respectively) on C₉ in acridine and the second nitrogen in phenazine. Excellent agreement has been obtained between the observed spin densities and those computed by INDO molecular orbital calculations. The design and construction of a simple rectangular ENDOR cavity operating in the TE₁₀₁ mode is described.