Sentence:  The DEAE-cellulose , containing 0.78 mEq of N / g , was prepared in our laboratory by the method of Peterson and Sober ( 7 ) from powdered <WSD>cellulose</WSD> , 100 - 230 mesh . 
Meaning of the word marked with <WSD> tags:  a polysaccharide that is the chief constituent of all plant tissues and fibers