374 SESSION IV. DISCUSSION 



is not known among non-living molecules. I have in mind, primarily, the dense envelope 

 of protein which protects the viral spore or virus particle. 



We have here been given well-founded evidence for the fact that viruses, being highly 

 specialized parasites, can hardly enable us to understand the earliest forms of life. From 

 this point of view a greater interest attaches to the saprophytic ultramicrobes which were 

 first isolated by Laidlaw from drain water and have now been fairly well studied. One 

 may wonder why they have not attracted the attention of specialists in the origin of Ufe. 



What has been said docs not detract from the significance of viruses in connection with 

 the study of the specific synthesis of proteins and other compounds of high molecular 

 weight. Twenty years ago, when I began my study of the physiology of viruses, I defi- 

 nitely had the idea that work in this direction was of importance, not merely for the 

 understanding of viruses, but also for the understanding of specific biosynthesis. I take 

 great satisfaction in the fact that this point of view is now generally accepted. 



A. N. Belozerskii (U.S.S.R.): 



May I say a few words in connection with Prof. Schramm's paper ? Prof. Schramm puts 

 forward the suggestion that polyphosphates, which are widely distributed in present-day 

 bacteria, played a part in the development of living things. The idea of the possible sig- 

 nificance of polyphosphates in the development of life was also thrown out by Prof. 

 Bemal in the lectures which he gave recently in Moscow University. Roka also postulates 

 the participation of polyphosphates in the original formation of desoxyribonucleic acid. 



It seems to me that everyone who is directly interested and concerned with the problem 

 of the origin and development of life on the Earth should pay attention to this group of 

 phosphorus-containing compounds which may really have played an essential part in the 

 establishment and further development of life. 



What circumstances lead to this suggestion ? 



In the first place, polyphosphates are only found in lower organisms, such as bacteria, 

 fungi and algae. The work of a considerable number of laboratories, including our own, 

 has shown that polyphosphates play an essential part in the vital activities of these micro- 

 organisms. They are directly associated with the phenomena of growth and multiplication, 

 or, to speak more concretely, they appear to be energy donors for such important bio- 

 syntheses as those of proteins and nucleic acids, while in the latter case they may also 

 serve as sources of phosphorus. 



According to Yoshida's findings polyphosphates should be regarded as high-energy 

 compounds. 



Only such polyphosphates as are associated with organic substrates are physiologically 

 active. Many investigators consider that physiologically active polyphosphates are bound 

 to proteins but, according to our evidence, they are bound to ribonucleic acid. In any 

 case, in one way or another, the utilization of these compounds of phosphorus by micro- 

 organisms takes place on the basis of organic compounds. 



In view of all this we may suppose that, at the time when living material became 

 established, inorganic polyphosphates already existed in nature, and that energy was 

 stored in this form. However, activation of the phosphates may have been necessary for 

 the directed use of this energy in organic syntheses, and this may have been brought about 

 by means of compounds of inorganic polyphosphates with some suitable pre-existing 

 organic compounds. 



Such an association may have led to the development of the prototype of later energy- 

 yielding systems which were perfected by selection in the course of further development. 



It is obviously not a matter of chance that, throughout the organic world, we find 

 energy-yielding systems in the form of derivatives of phosphoric acid or, more accurately, 

 derivatives of polyphosphates. 



It is not impossible that a similar means for the storage of energy in the organic world 

 was, at some time, brought in from inorganic nature, in the form of mineral polyphosphates. 



