87 



it also more unstable, preventing tiie transition of singlets into 

 triplets and making the triplets drop back more easily into the 

 ground state. 



Such action of sugars may have its biological bearing. Deoxy- 

 ribose nucleic acid consists according to the Watson Crick model 

 of a column of heterocyclic bases surrounded by a sheet of pentose 

 and phosphoric acid. If the bases are instrumental in conducting 

 energy then the water structures built by the sugars and phosphates 

 may be instrumental in transmitting this energy to the outside and 

 transmitting with it also the genetic information contained in 

 DNA. Solutions of DNA (as well as those of RNA) show a 

 fluorescence in the visible, which turns into a long-lived phospho- 

 rescence on freezing. None of the components of nucleic acid 

 shows such phosphorescence in itself, which indicates some col- 

 lective activity in relation to the energy communicated to the sys- 

 tem. A long-lived phosphorescence in dissolved substances is, 

 without the addition of some stabilizer, such as glucose, a verj' 

 rare occurrence. Evidently, the nucleic acid contains both compo- 

 nents: the phosphorescent heterocyclic bases, and a pentose (and 

 possibly also phosphate) as stabilizer. 



The weak, short-lived phosphorescence of a frozen acridine 

 orange solution is turned into a strong and long-lived one also by 

 low concentrations (10"^ Af) of ATP. This reaction is due to two 

 factors, firstly to the formation of a stable complex between ATP 

 and the dye which readily precipitates if the reactants are present 

 in higher concentration. Adenosine monophosphate behaves simi- 

 larly though the phosphorescence of its complex was weaker than 

 that of ATP. Phosphorescence was found to be absent with ade- 

 nine, though it also complexed with the dye. Evidently, icebergs 

 of the pentose and the phosphate were responsible for the stabili- 

 zation of £* in the ATP-dye complex, which icebergs may play a 

 major role also in muscular contraction. 



It is not enough for a molecule to be hydrophylous and build 

 icebergs in order to produce long-lived excitations in dyes. 



