690 



I 



Shigetoh Miyachi 



shown were devised to separate the inorganic polyphosphates. It has 

 been found that during the neutralization of the 2 NKOH -extract with PC A 

 (Procedure V, see Methods) not only Poly-P"C" but also an appreciable 

 amount of DNA and protein is co -precipitated with potassium perchlorate, 

 so that the values obtained in these compounds are smaller than they 

 should be. This co-precipitation of DNA and protein can be avoided if 

 the extraction is done with 0. 5N instead of 2 NKOH. On the other hand, 

 poly-P"C" is not precipitated completely during the neutralization of a 

 0. 5 NKOH extract with PCa(^). 



Changes of distribution of en dogenous P^^ occurring on incubating P^^- 

 labeled Chlorella in P-free medium 



Experiment in light - Changes in P^^ -content in various fractions in 

 normal labeled cells were followed in P-free medium. It has already 

 been reported^''') that the P^^ -contents in the fractions of DNA and pro- 

 tein increased significantly, while only those in poly-P"A", poly-P"B" 

 and poly-P"C" decreased markedly. As may be seen in Fig. 2, RNA- 

 P^2 increased while poly-P^^ "D" decreased steeply. Acid insoluble 

 nucleotidic labile p32 decreased slowly. P^^ jj^ "total RNA -fraction" 

 kept constant or decreased only slightly as reported previously. It was 

 found also that the increase in RNA-P-^^ was accompanied by an increase 

 in UV-absorbancy (E260) ^^ ^^^^ ^s of the amount of ribose, confirming 

 that RNA continues to be synthesized under P-deficiency in light. Thus 

 it may be inferred from the present as well as previously published re- 

 sults that, under photosynthetic condition in P-free medium, P used for 

 the syntheses of DNA, RNA and P-protein is supplied from inorganic 

 phosphates. 



Experiment in darkness - When some Chlorella cells were incubated 

 in a P-deficient medium in the dark an appreciable decrease of P-content 

 was observed only in the fraction of polyphosphate "B". In parallel with 

 this decrease, an increase of P occurred only in the RNA-fraction, in- 

 dicating that, under non-photosynthetic conditions, RNA is synthesized 

 with the expenditure of phosphorus of polyphosphate "B". It may be 

 assumed that the mobilization of phosphorus in polyphosphates for the 

 syntheses of DNA and phosphorprotein is a light-induced process, and 

 that in the dark, poly-P "B" serves as the P-donor for the synthesis of 

 RNA, while this process is blocked under photosynthetic conditions^ '°^ 

 In some other cultures of the same species of Chlorella, however, the 

 dark synthesis of RNA with the expenditure of poly-P "B" was not 



