292 SESSION III. DISCUSSION 



of evolution. To adapt the terminology of A. N. Severtsov, one may say that, in com- 

 parison with racemic protoplasm, optically active protoplasm represents considerable 

 progress or apomorphosis. 



In the second place: Why docs all the protoplasm we know on the Earth have the L- 

 configuration, the D- stereoisomers of amino acids being absent from its structure ? Why 

 has D-protoplasm never been found on the Earth ? Obviously this indicates a common 

 origin for all the life we know, from a single source. 



A further very interesting question is that of the connection between inverse forms of 

 organisms and inverse molecules in their composition. In cases when such phenomena 

 have been studied in detail, as in Bacillus mycoides, it has been shown that in both the rare 

 right-spiral and the typical left-spiral bacteria the protoplasm has the L-configuration and 

 the inversion of form is evidently associated with optical inversion of some component of 

 the bacterial cell wall. Unfortunately, it is today as it was 17 years ago when I wrote my 

 book The Asymmetry of Protoplasm ; we have not succeeded in isolating optically rotatory 

 compounds from the cell walls of inverse bacteria and, therefore, nobody has yet been 

 able to give direct experimental proof of the association between inverse forms of organisms 

 and inverse molecules entering into their composition. We may hope that recent advances 

 in the study of the chemical composition of the cell walls of bacteria and, in particular, 

 the isolation from them of individual amino acids and a study of their optical rotation will 

 be applied to work with right-spiral and left-spiral forms and will lead to a final solution 

 of the question of the connection between morphological inversion and molecular 

 inversion. 



E. M. Makovskii (Rumania): 



I want to give you hearty greetings from the people of Rumania and from the Rumanian 

 scientists who are looking forward with great interest to the results of this Symposium. 



Rumania is active in the struggle for peace, so I can assure Prof. Pauling that the idea 

 of organizing peaceful international symposia of politicians and diplomats meets with 

 our deepest sympathy. 



Turning to our discussion, I wish to say a few words about what Prof. Akabori has 

 told us today. 



I find his hypothesis about the possibility of the formation of protopolypeptide chains 

 by the action of aldehydes and unsaturated hydrocarbons on polyglycine interesting 

 because with some amplification it might lead to an explanation of the appearance on 

 the Earth of the first polypeptides with a periodic structure. 



Investigations carried out by Prof. I. Tanasescu and his school, begirming in 1928 

 in the town of Cluj, showed that the action of light on cyclic o-nitrobenzyhdene acetals of 

 polyols led to photochemical isomerization of some, but not all, of the photochemically 

 active groups, even when they seemed to be similar in all respects. The periodicity tlius 

 reveals its nature by its activity in the sense that if one group reacts photochemically its 

 neighbour will not react and it will only be the third group which will react. 



This leads to the idea, which needs to be tested experimentally, that the methylene 

 groups of polyglycine might also, under certain circumstances, manifest periodic differ- 

 ences of potentialities in respect of their reactions with different aldehydes. In this case 

 one and the same polyglycine chain, in the presence of a mixture of different aldehydes, 

 might, from the very beginning, form a polypeptide chain having a periodic distribution 

 of amino acids. 



From this point of view, periodically constructed polypeptides, though, of course, of 

 comparatively simple structure, might be seen as prototypes of the present-day protamines 

 in which such a structural periodicity has been well demonstrated. 



The fact to which Prof. Felix referred, that contemporary protamines, in combination 

 with nucleic acids, play an important part in heredity, emphasizes once more the signifi- 

 cance of comparatively simple periodic polypeptide structures in connection with the 

 problem of the origin of life. Prof. Akabori's hypothesis sheds new light on the possibility 

 that such structures were produced right at the beginning of the evolution of organic 

 substances on the Earth. 



