Agrin in Alzheimer’s disease: Altered solubility and abnormal distribution within microvasculature and brain parenchyma

Agrin is a heparan sulfate proteoglycan that is widely expressed in neurons and microvascular basal lamina in the rodent and avian central nervous system. Agrin induces the differentiation of nerve-muscle synapses, but its function in either normal or diseased brains is not known. Alzheimer’s disease (AD) is characterized by loss of synapses, changes in microvascular architecture, and formation of neurofibrillary tangles and senile plaques. Here we have asked whether AD causes changes in the distribution and biochemical properties of agrin. Immunostaining of normal, aged human central nervous system revealed that agrin is expressed in neurons in multiple brain areas. Robust agrin immunoreactivity was observed uniformly in the microvascular basal lamina. In AD brains, agrin is highly concentrated in both diffuse and neuritic plaques as well as neurofibrillary tangles; neuronal expression of agrin also was observed. Furthermore, patients with AD had microvascular alterations characterized by thinning and fragmentation of the basal lamina. Detergent extraction and Western blotting showed that virtually all the agrin in normal brain is soluble in 1% SDS. In contrast, a large fraction of the agrin in AD brains is insoluble under these conditions, suggesting that it is tightly associated with β-amyloid. Together, these data indicate that the agrin abnormalities observed in AD are closely linked to β-amyloid deposition. These observations suggest that altered agrin expression in the microvasculature and the brain parenchyma contribute to the pathogenesis of AD.

Solubility, Density, Refractive Index, and Viscosity for the Polyhydric Alcohol + CsBr + H2O Ternary Systems at Different Temperatures

The solubility, density, refractive index, and viscosity data for the ethylene glycol + CsBr + H2O, 1,2-propanediol + CsBr + H2O, and glycerin + CsBr + H2O ternary systems have been determined at (288.15, 298.15, and 308.15) K. In all cases, the solubility of CsBr in aqueous solutions was decreased significantly due to the presence of polyhydric alcohol. The liquid–solid equilibrium experimental data were correlated using the NRTL (nonrandom two-liquid) activity coefficient model, considering nondissociation of the dissolved salt in the liquid phase, and new interaction parameters were estimated. The mean deviations between calculated and experimental compositions were low, showing the good descriptive quality and applicability of the NRTL model. The refractive indices, densities, and viscosities for the unsaturated solutions of the three ternary systems have also been measured at three temperatures. Values for all of the properties were correlated with the salt concentrations and proportions of polyhydric alcohol in the solutions.

Helium in solubility equilibrium with quartz and porefluids in rocks - a new approach in hydrology

Quartz crystals in sandstones at depths of 1200 m–1400 m below the surface appear to reach a solubility equilibrium with the 4He-concentration in the surrounding pore- or groundwater after some time. A rather high 4Heconcentration of 4.5x10E-3 cc STP 4He/cm3 of water measured in a groundwater sample would for instance maintain a He pressure of 0.47 atm in a related volume. This value is equal within analytical error to the pressure deduced from the measured helium content of the quartz and its internal helium-accessible volume. To determine this volume, quartz crystals of 0.1 to 1 mm were separated from sandstones and exposed to a helium gas pressure of 32 atm at a temperature of 290°C for up to 2 months. By crushing, melting or isothermal heating the helium was then extracted from the helium saturated samples. Avolume on the order of 0.1% of the crystal volume is only accessible to helium atoms but not to argon atoms or water molecules. By monitoring the diffusive loss of He from the crystals at 350°C an effective diffusion constant on the order of 10E-9 cm2/s is estimated. Extrapolation to the temperature of 70°C in the sediments at a depth of 1400 m gives a typical time of about 100 000 years to reach equilibrium between helium in porewaters and the internal He-accessible volume of quartz crystals. In a geologic situation with stagnant pore- or groundwaters in sediments it therefore appears to be possible with this new method to deduce a 4He depth profile for porewaters in impermeable rocks based on their mineral record.

Chemical composition and solubility of ocean phosphatized rocks in seawater

In order to elucidate possibility of limestone phosphatization during contact with seawater two sets of experiments were carried out: that of solubility of natural phosphates in seawater and that of deposition of phosphorus onto calcareous phase. Concentration of phosphorus in seawater used for solubility experiments varied from 39 to 338 µ/l, temperature was 5.5-17.5°C and pH 7.8-7.9. The lowest solubility was characteristic of ancient crystallized samples. The deposition experiments showed that in case when concentration of dissolved phosphate in seawater reaches 3 mg/l it might be sorbed on solid CaCO3 phase without forming its own mineral. The latter is able to form rapidly but only if magnesium is not present in solution. In magnesium-free water calcium phosphates precipitate when concentration of dissolved phosphorus is higher than 0.9-1.2 mg/l. These results show that phosphatization of limestones in marine environment takes place during their contact with pore water but not with marine bottom water.

The solubility of helium in lithium and potassium /

"Contract AT(30-1)-2789."

Solubilities of inorganic and organic compounds : supplement to the third edition containing data published during the years 1939-1949 inclusive : a compilation of quantitative solubility data from the periodical literature /

Mode of access: Internet.

Soil, Clay, and caustic soda effects on solubility, sorption, and mobility of hexachlorocyclopentadiene /

Bibliography: p. 51-54.

Solubilities of inorganic and organic substances; a handbook of the most reliable quantitative solubility determinations,

Mode of access: Internet.

Solubilities of inorganic and metal organic compounds; a compilation of quantitative solubility data from the periodical literature.

Vol. 2 has title: Solubilities of organic compounds.

The solubility of nonelectrolytes,

Mode of access: Internet.

The solubility of carbon dioxide in distilled water, synthetic sea water and synthetic sea-water concentrates,

Mode of access: Internet.

Boron solubility in Fe-Cr-B cast irons

Boron solubility in the as-cast and solution treated martensite of Fe-Cr-B cast irons, containing approximately 1.35 wt.% of boron, 12 wt.% of chromium, as well as other alloying elements, has been investigated using conventional microanalysis. The significant microstructural variations after tempering at 750 degreesC for 0.5-4 h, compared with the original as-cast and solution treated microstructures, indicated that the matrix consisted of boron and carbon supersaturated solid solutions. The boron solubility detected by electron microprobe was between 0.185-0.515 wt.% for the as-cast martensite and 0.015-0.0589 wt.% for the solution treated martensite, much higher than the accepted value of 0.005 wt.% in pure iron. These remarkable increases are thought to be associated with some metallic alloying element addition, such as chromium, vanadium and molybdenum, which have atomic diameters larger than iron, and expand the iron lattice to sufficiently allow boron atoms to occupy the interstitial sites in iron lattice. (C) 2002 Elsevier Science B.V. All rights reserved.

Adsorption of flexible n-alkane on graphitized thermal carbon black: analysis of adsorption isotherm by means of GCMC simulation

In this paper, we investigate the suitability of the grand canonical Monte Carlo in the description of adsorption equilibria of flexible n-alkane (butane, pentane and hexane) on graphitized thermal carbon black. Potential model of n-alkane of Martin and Siepmann (J. Phys. Chem. 102 (1998) 2569) is employed in the simulation, and we consider the flexibility of molecule in the simulation. By this we study two models, one is the fully flexible molecular model in which n-alkane is subject to bending and torsion, while the other is the rigid molecular model in which all carbon atoms reside on the same plane. It is found that (i) the adsorption isotherm results of these two models are close to each other, suggesting that n-alkane model behaves mostly as rigid molecules with respect to adsorption although the isotherm for longer chain n-hexane is better described by the flexible molecular model (ii) the isotherms agree very well with the experimental data at least up to two layers on the surface.

Phosphorus nutrition of Caustis blakei grown with two phosphorus sources of different solubility in two soils of differing phosphorus adsorption capacity

A barrier to the domestication of the phosphorus (P) sensitive Australian species Caustis blakei (Cyperaceae) is the standard production systems used commercially which invariably result in problems associated either with P deficiency or P toxicity. This paper reports on the growth responses of Caustis blakei cv. M63 to applications of fertiliser P as either monocalcium phosphate (MCP) or granulated Guano Gold (R) rock phosphate (RP) in two soils with different capacities to adsorb P. The Caustis M63 plants grown in the two soils did not show P toxicity symptoms when fertilised with RP, but shoot dry weight was 30-60% lower than the control in both soils at the highest rate of MCP-P application (156 kg ha(-1), 184 g m(-3)) and this was associated with visible symptoms of drying of the tips of the ultimate branchlets, in the Mt Cotton soil only. The greatest shoot and root dry weights were achieved by plants grown in the higher P adsorbing Palmwoods soil fertilised with RP at P rates of 30-184 g m(-3). Caustis plants grown in the Palmwoods soil had 2.3 times greater root dry weights than plants grown in the Mt Cotton soil irrespective of the P fertiliser type used. Caustis plants growing in Mt Cotton soil which did not receive P showed significantly lower shoot and root dry weight when compared to plants in the Palmwoods soil, probably due to the low initial bicarbonate-extractable P and the high buffering capacity of the Mt Cotton soil. The P concentration in shoots of Caustis fertilised with MCP at 184 g m(-3) was higher when grown in Mt Cotton soil (0.22%) than in the Palmwoods soil (0.15%). The P concentration was lower in the terminal ultimate branchlets (TUB); 0.15% for the Mt Cotton soil and 0.10% for the Palmwoods soil, suggesting that shoots would provide a more useful indicator of P toxicity than the TUB. It is interesting to speculate as to why plants in the Palmwoods soil showed greater root growth and fewer symptoms of P toxicity. This could be because the Palmwoods soil had the greater P adsorption capacity. These results indicate in ground production of Caustis cut foliage will require careful management of P nutrition and understanding of the complex soil/plant interactions associated with the acquisition of P. (c) 2006 Elsevier B.V. All rights reserved.

Incorporating a TEV cleavage site reduces the solubility of nine recombinant mouse proteins

Failure to express soluble proteins in bacteria is mainly attributed to the properties of the target protein itself, as well as the choice of the vector, the purification tag and the linker between the tag and protein, and codon usage. The expression of proteins with fusion tags to facilitate subsequent purification steps is a widely used procedure in the production of recombinant proteins. However, the additional residues can affect the properties of the protein; therefore, it is often desirable to remove the tag after purification. This is usually done by engineering a cleavage site between the tag and the encoded protein that is recognised by a site-specific protease, such as the one from tobacco etch virus (TEV). In this study, we investigated the effect of four different tags on the bacterial expression and solubility of nine mouse proteins. Two of the four engineered constructs contained hexahistidine tags with either a long or short linker. The other two constructs contained a TEV cleavage site engineered into the linker region. Our data show that inclusion of the TEV recognition site directly downstream of the recombination site of the Invitrogen Gateway vector resulted, in a loss of solubility of the nine mouse proteins. Our work suggests that one needs to be very careful when making modifications to expression vectors and combining different affinity and fusion tags and cleavage sites: (c) 2006 Elsevier Inc. All rights reserved.