Sentence:  Specific staining by DEAE-cellulose treated * * f and * * f , although clearly distinguishable under the microscope from either nonspecific staining or autofluorescence of <WSD>cells</WSD> , was not satisfactorily photographed to show such differences in spite of many attempts with black and white and color photography . 
Meaning of the word marked with <WSD> tags:  (biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals