REDUCED DYES AND ESR SPECTRA 349 



the light-induced free radical due to chromatophore components (bac- 

 teriochlorophyll). 



ACKNOWLEDGMENTS 



The authors gratefully acknowledge the aid of Mrs. F. Lubbers and Dr. S. 

 Hood, who supplied the cultures and chromatophore preparations. We wish to 

 thank Dr. H. Beinert and Mr. R. Hansen for the data of Fig. 2. 



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