The Effect of Nutritional and 

 Environmental Conditions of Sporulation 



Z. John Ordal 



Food Technology Department, University of Illinois, Urbana, Illinois 



KNAYSI (1948) in his review entitled "The Endospore of Bacteria" 

 gave us a rather complete account of the information available up 

 to that time on the effects of nutritional and environmental factors 

 on sporulation, especially in regard to members of the genus Bacillus. 



It is my purpose today to bring to your attention some of the pertinent 

 data that have appeared since then, and to present, rather briefly, several 

 examples from unpublished data obtained in our laboratory. It is also my 

 concern to stimulate discussion on some of the important issues which are 

 still ambiguous and controversial. 



First of all, I must emphasize the fact that our knowledge about "why 

 and how" a vegetative cell sporulates is still very limited. Four main hypoth 

 theses have been suggested as explanations. The first and oldest is that o 

 Behring (1889) : "Sporulation is an intermediate stage in the normal de 

 velopment of the bacterial cell, which may be partially or completely in 

 hibited by some partial physiological damage short of total prevention o 

 growth." The second is Knaysi's (1948) : "Endospores are formed by 

 healthy cells facing starvation." The third, which is a more specific version 

 of Behring's is that of Foster and Heiligman (1949b) : "Sporulation is a 

 sequence of integrated biochemical reactions which are independent of 

 vegetative growth and may be interrupted at certain susceptible stages." 

 The fourth, which is rather supplementary but not specific, is Schmidt's: 

 "Sporulation is a function both of the environment and of cellular factors 

 determining the reaction of the cell to a given environment." 



These several hypotheses are not necessarily mutually exclusive; and it 

 is not my purpose at this time to prove or disprove any of them. But, for 

 the sake of this presentation and perhaps as a basis for discussion, let me 

 assume that we are in agreement on the following concept: Sporulation is 

 a normal metabolic process which will occur within the bacterial cell only 

 when (1) the cell is of a sporogenous type; (2) the cell acquires the proper 

 physiological condition; and (3) the cell is surrounded by the proper en- 

 vironment. 



At this point I must emphasize that much of our information comes from 

 observations made on growing cultures; and investigators have not always 



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