Definition of "nuclein" [nu•cle•in]

• Any of the substances present in the nucleus of a cell, consisting chiefly of proteins, phosphoric acids, and nucleic acids. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The essential and indispensable element of the nucleus is called nuclein (or caryoplasm); that of the cell body is called plastin (or cytoplasm)."
• "Because it resided in the nuclei of cells, he called it "nuclein"."
• "The small central particle of nuclein which is formed from this combination of the nuclei is the stem-nucleus, or the first segmentation nucleus; the new-formed cell, the product of the impregnation, is our stem-cell, or "first segmentation sphere" (Figure"