42 S. S. COHEN 



fused. At this stage, about half of the protein had disappeared and the DNA 

 was extensively depolymerized but not lost from the nucleus, as measured by 

 stainability with methyl green and by the Feulgen method. Later, the DNA 

 also progressively disappeared and it was suggested that the maintenance of 

 histone content is important for preservation of the highly polymerized state 

 of the associated DNA. Nevertheless, it is known that deoxyribonuclease 

 depolymerizes DNA, even when associated with histone. It was concluded 

 that pycnosis involves an initial high proteolytic activity in the nucleus, 

 followed by action of nuclease. 



TABLE III 

 Ploidy — Dependent Characters in Saccharomyces ** 



Haploid Diploid Triploid Tetraploid 



DNA-P/cell f> 2.26 ± 0.23 4.57 d= 0.60 6.18 ± 0.54 9.42 ± 1.77 



RNA-P/cell ^ 55.6 ± 16.6 96.5 ± 22 A 164.0 ± 33.6 172. ± 6. 



Meta-P/cell& 100.1 ±25.8 166.5 ±31.2 217.8 ±57.7 362. ±34. 



Dry wt./cell « 1.38 ± 0.23 2.70 ± 0.61 3.40 ± 0.67 7.29 ± 0.5 



Q Oa/cell 7.93 ± 2.7 16.5 ± 2.7 24.6 ± 3.3 33.2 ± 3.4 



QC02(air)/cell 19.3 ± 4.2 33.3 ± 6.7 49.9 ± 6.3 77.5 ±14.2 



« Ogur et al. (1952), Ogur (1954). ^ Units /xg (X lO* for P data). 



" jLig (X 10^ for dry wt. data). 



The depolymerization of the DNA of mesenchymal cells is also a feature of 

 lupus erythrematosis (L.E.). The bone marrow of patients with this disease 

 show the L.E. cell, a polymorphonuclear granulocyte whose cytoplasm con- 

 tains a homogeneous basophihc mass comprised of depolymerized DNA. 

 L.E. sera contain a y-globulin fraction capable of binding to intranuclear 

 DNA (Holman and Kunkel, 1957). The relation of this reaction to the pro- 

 duction of the L.E. cell and the disease entity is being studied in many 

 laboratories. 



c. Mineral Constituents. Data on the distribution of inorganic constituents 

 in cells have been relatively meagre until the recent study of Thiers and Vallee 

 (1957). Little can be said about their presence within the nucleus. As sum- 

 marized by Horning (1951), microincineration studies of this structure in situ 

 have revealed the presence of fair amoimts of ash, probably calcium (Ca) and 

 magnesium (Mg) salts, in chromatin. The presence of these cations is par- 

 ticularly marked in certain states of mitosis, such as late prophase and 

 metaphase. Conversely, the "resting" nuclei of ganghon cells were apparently 

 ash-free, with the exception of the nucleoh. The presence of significant 

 amounts of iron (Fe) in the latter has been claimed. 



