THE GROWTH OF SACCHARIDE MACROMOLECULES 323 



References 



1. Albertsson, P. A., these proceedings, Vol. i, p. 33. 



2. Oparin, A. I., in "The Origin of Life ", First International lUBS Symposium. 

 Pergamon Press, London, 428 (1959). 



3. Koshland, D. E., Jr., in "The Enzymes", Vol. i, ed. P. Boyer et ol. Academic 

 Press, New York, 305 (1959). 



4. Hestrin, S., Feingold, D. S., and Avigad, G., Biochem.J. 64, 340 (1956). 



5. Greathouse, G. A., J. Amer. chem. Soc. 79, 4503 (1957). 



6. Stacey, M., in "Soc. Exp. Biol. Symposium XII". Cambridge University 

 Press, Cambridge, 185 (1958). 



7. Glaser, L.,7- hioL Chem. 232, 627 (1958). 



8. Colvin, J., Arch. Biochem. Biophys. 7, 294 (1957); Colvin, J., Nature, Loud. 

 183, 1 135 (1959)- 



9. Klungsoyr, S., Nature, Lotui. 185, 104 (i960) 



10. Schramm, AL, Gromet, Z., and Hestrin, S., Nature, Loud. 179, 28 (1957). 



11. Miihlethaler, K., Biochim. biophys. Acta 3, 527 (1949). 



12. Hall, C. E., J. biophys. biochem. Cytol. 2, 625 (i960). 



13. Cf. review by Frey-Wyssling, A. in "Symposium on BiocoUoids ", _7. cell, 

 comp. Physiol. 49, (Supplement i), 63 (1957). 



Discussion 



Rogers : I wonder if Dr. Hestrin could tell us a little more about his comparison 

 of the rate of synthesis of cellulose by the UPDG system and his system, because 

 these comparisons are a little difficult to make especially when you are isolating 

 particles from bacteria with rather tough cell walls. It is a little difficult to know 

 what proportions of "particles" you have got out of the organisms, or how damaged 

 or undamaged the preparation is. The second point I am not quite clear about, 

 although I think you may have explained it already, is why you used fructose in 

 these experiments, because if the UDPG system were functioning then presumably 

 the fructose must get in, be reconstituted to the appropriate glucose-phosphate, the 

 UDPG be made and this transferred back to the cellulose and during the process 

 I would have thought there was an equal chance that endogenous supplies of glucose 

 might be used in preference to fructose, in any case the penetration of cells by 

 fructose is sometimes rather difficult. 



Hestrin : As in the work reported by Glaser, we were only able to recover about 

 I °o or less of the cellulose-synthesizing activity of the cells in the equivalent 

 amount of particle. Even on a weight per weight basis, the activity of the particle 

 was less than that of the cell. 



The advantage of using fructose as a substrate in the synthesis of radioactive 

 cellulose relates to the circumstance that fructose does not appear to be subject to a 

 direct oxidation, whereas glucose tends to be oxidized to gluconate and thence to 

 ketogluconate isomers each of which in turn can give rise to cellulose. The existence 

 of many alternate pathways by which glucose can form cellulose complicates the 

 calculation of the distribution which '^C supplied as glucose may be expected to 

 assume in the synthesized cellulose. Using fructose, however, we have no glu- 

 conate, we have no ketogluconate, but we still have of course, all the intermediates 



