Dextran Sulfate Solution Research Articles

Precipitation of acidic polysaccharides by salts in ethanol–water mixtures

AbstractThe results of the present investigation show that precipitation with ethanol and inorganic salts may be a useful tool for the separation of the components of a polysac‐charide mixture. The solubility of neutal polysaccharides in ethanol–water mixtures is independent of the presence of salt except for high salt concentrations. The presence of anionic groups in the polysaccharide makes the solubility of the compound sensitive to the presence of ions, and the effect of the different cations depends on the type of anionic group on the polymer. Determination of cation activity by a cationic electrode revealed no correlation between the formation of ion pairs and the precipitating effect of the different cations. Viscosity determinations of dextran sulfate solutions showed that the viscosity at the salt concentration leading to precipitation was independent of the type of salt used. This result indicates that the different ion pairs formed on the polymer chain have a different effect on the interaction between the solvent molecules and the chain segments. Experiments with alginate showed that the divalent cations caused precipitation at higher viscosities than the monovalent ions, indicating that the divalent ions in this case have a different effect, probably by forming intermolecular bonds.

NEW METHOD FOR PURIFYING COXIELLA BURNETII BY DEXTRAN SULFATE PRECIPITATION FOLLOWED BY CENTRIFUGATION.

This paper describes a simple method for purifying Coxiella burnetii cultivated in the chick embryo. The procedure is based upon the preliminary clarification of infected whole-egg suspensions by precipitating the low-density lipoproteins and other extraneous solids with dextran sulfate, calcium chloride, and sodium chloride solutions, and then concentrating the rickettsiae by centrifugation.

New Method for Purifying Coxiella burnetii by Dextran Sulfate Precipitation Followed by Centrifugation

This paper describes a simple method for purifying Coxiella burnetii cultivated in the chick embryo. The procedure is based upon the preliminary clarification of infected whole-egg suspensions by precipitating the low-density lipoproteins and other extraneous solids with dextran sulfate, calcium chloride, and sodium chloride solutions, and then concentrating the rickettsiae by centrifugation.