Penetration of Arsenic into Living Cells 39 

 14 (1974) 



The penetration of arsenic into living cells 1 . 

 By MATILDA MOLDENHAUER BROOKS (by invitation) 



[From the Division of Pharmacology, Hygienic Laboratory, 

 Washington, D. C] 



The purpose of these experiments was to study directly the 

 penetration of arsenic into living cells. The organism used was 

 the fresh water alga Nitella, which furnishes single cells several 

 inches in length, whose contents may be easily expressed and 

 analysed. Freshly collected cells only were used. 



To determine whether there is any relation between H ion 

 concentration and arsenic penetration ten .033 M phosphate 

 buffer solutions were made up covering the range P H 5.6 to 7.5, 

 and at least twenty-five cells of Nitella placed in each of these 

 for each experiment. After 24 hours counts were made of the 

 number of cells still in good condition, i.e., turgid and with cell 

 sap clear and free from chloroplasts. 



A series of similar experiments was performed in which 

 arsenic in the form of atoxyl was added to the buffer solutions 

 in sufficient quantity to make the concentration of atoxyl .05 M ; 

 and still another series in which a set of 0.05 M arsenate buffers 

 was used (arsenic acid plus NaOH) having the same P H range 

 as the phosphate buffers. In each case the proportion of cells 

 of Nitella still in good condition after 24 hours in the solutions 

 was determined. 



In both experiments with arsenic the sap of all the cells in 

 good condition was expressed (precautions for preventing con- 

 tamination being taken), a constant quantity (0.036 c.c.) in- 

 cinerated, and the arsenic determined by the Gutzeit method, 

 which is sensitive to about one micromilligram. 



All experiments were conducted at laboratory temperature, 

 which was usually not far from 20° C. 



1. The influence of both hydrogen ions and buffer salt ions 

 upon the condition of Nitella is shown by the facts that : 



i Approved for publication by the Surgeon General, U. S. Public Health 

 Service. 



