The Submicroscopic Basis of Bacterial 

 Photosynthesis: The Chromatophore' 



J. A. Bergeron " and R. C. Fuller - 



Introduction 



The preceding symposium papers have considered submicro- 

 scopic aspects of objects with which biologists are aheady famihar 

 at the microscopic or gross anatomical level, i.e., the collagenous 

 fiber, the chloroplast, the mitotic spindle, and the myelin sheath. By 

 contrast, the subject of this paper is less familiar because the bac- 

 terial chromatophore is itself submicroscopic and, as a consequence, 

 was not identified until recently. Since the subject is new, it seems 

 apropos to indicate the value ot the bacterial chromatophore for 

 studying photosvnthesis. 



Sixteen years ago, Ruben (1943) suggested that the energy of 

 the pyrophosphate bond of adenosine triphosphate (ATP) could 

 supply the energy needed for the photosynthetic assimilation of 

 carbon dioxide. The following year, Emerson et al. ( 1944 ) proposed 

 that the function of light energy in photosynthesis is the formation 

 of energy-rich phosphate bonds. The concept of ATP as the fuel 

 of photosynthesis gradually gained acceptance as the path of car- 

 bon during photosynthesis became clearer and as knowledge of 

 carbohydrate phosphate interconversion improved. The search for 

 a direct relation between light absorption and ATP formation cul- 

 minated with the demonstration of photosynthetic phosphorylation 

 by chloroplast preparations (Anion et at, 1954a, 1954b) and by sub- 

 cellular preparations of the non-sulfur purple bacterium, Rhodo- 

 spirillum rubrum (Frenkel, 1954). Currently, the mechanism by 



' Research carried out at Brookhaven National Laboratory under the auspices of 

 the U. S. Atomic Energy Commission. We are indebted to Mr. Mark Gettner, Mr. 

 Walter Geisbusch, and Misses Gayle Schaeff, Catherine Kostuk, and Geraldine David 

 for technical assistance. 



- Biology Department, Brookhaven National Laboratory, Upton, New York. 



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