Source and Preparation of Dextran

From this list of microorganisms capable of synthesizing dextran, it may readily be seen that one of the factors controlling the properties of the polysaccharide obtained is the strain of the particular bacterium used. This observation has been amply verified in a number of studies. Thus, immunological cross-reactions of dextrans with pnemnococcus antisera, the results of periodate oxidations, - and various physical measurements - have all demonstrated this point. 

When the dextran has been formed, it is usually isolated by the addition of ethanol to the cultiu-e filtrate. - The precipitated dextran may be further purified by dissolving it in water and reprecipitating it with ethanol.  

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