Proliferation-promoting Activities of Extracts from Ultra-violet Injured Yeast Cells and of Bios Components

Abstract

NUMEROUS papers from these laboratories have dealt with the production of proliferation-promoting factors ('intercellular wound hormones') by cells subjected to various injuring agents. It seems warranted to believe that these substances are produced by living, injured cells as a response to injury and are not simply dead-cell disintegration products¹. The question of the nature of these materials is of great interest. It might be assumed that they are merely normal growth substances produced or released in greater quantities under the conditions of injury, or it is possible that they represent specific 'injury substances'. Two lines of inquiry have been undertaken to answer the question: (1) chemical and spectrographic studies, which suggest a nucleic acid-like nature for the wound hormones and which definitely show that substances of this type are produced in greater quantity as a result of injury² ; (2) comparative growth studies, on the wound hormone preparations and known growth substances. The present note is concerned with the latter.