448 BACTERIAL PHOTOSYNTHESIS 



in addition to the uncertainties which attend investigation at any partic- 

 ular instant, there is also an uncertainty in time. Breakage of the cell 

 by mechanical means leads to the formation of membrane fragments, 

 heterogeneous in size, which bear the pigments in a photochemical 

 electron transport system. When comminutive treatment, such as 

 sonic oscillation, is used to disrupt a cell, the average size of mem- 

 brane fragments obtained decreases with the duration of treatment. By 

 differential centrifugation of bacterial extracts, the membrane frag- 

 ments that are homogeneous in size and density may be separated; 

 and these homogeneous preparations and particles have usually been 

 found to be from 300 to 600 angstroms in diameter. These particles 

 were originally designated as 'chromatophores,' Hoivever, this term 

 is now undesirable because it itnplies that such independent structures 

 exist in the cell before destruction . There is no evidence to support 

 this assumption, [italics mine,] Nevertheless, some descriptive term 

 applicable to the photochemically active particulate preparation that 

 can be obtained after cell disruption is needed. We propose that any 

 such preparation should be designated as a 'chromatophore fragment,' 

 Irrespective of the particle size or homogeneity, any such fraction 

 should be defined operationally in terms of the methods used for its 

 preparation," So that is the statement. 



From now on, we have "chromatophore fragments," regardless of 

 size or homogeneity, but there has to be somewhere in any paper deal- 

 ing with them an accurate description of how they were obtained and 

 preferably, maybe some pictures. Well, perhaps we won't ask for the 

 pictures, but at least there should be some description of the culture 

 conditions of the organism, its age, the media used, the number of 

 times it was washed, and even perhaps a designation of the strain 

 (if you can obtain this from some local expert) and how many years 

 you've had this strain. It might even be a good idea to have occasional 

 comparisons or recalibrations of the strain, and finally, the nature 

 of the equipment used to break up the cell, in detail. This brings us to 

 the end of the first day. 



The second day brought us to a more vexatious point. The question 

 of "cyclic" versus "noncyclic" photophosphorylation, and also, of 

 course, the metabolic aspects in general of bacterial photosynthesis, 

 with some digressions on the nature of the present character, or 

 present status, of the unitary theory of photosynthesis, whatever it may 

 be. The unitary theory has taken many forms since the Thirties, and 

 there have been a number of suggestions as to what the primary 

 chemistry should be to define a unitary theory. The primary chemical 

 process back in 1935 was the "splitting of water," and everything was 

 classified in terms of what happened in reactions involving the 

 products of splitting of water. This is still, for purposes of classifica- 

 tion, a perfectly fine scheme. It is not intended to imply a mechanism, 

 and it is necessary that we should be looking for definitions which will 



