ABSORPTION SPECTRA OF PHOTOSYNTHETIC 

 BACTERIA AND THEIR CHLOROPHYLLS 



RODERICK K. CLAYTON 



The materials selected for presentation are from Rho do spirillum 

 rubrum, Rhodopseudomonas spheroides, Chromatium, Rhodomicro- 

 bium vannielii, Chlorobium thiosulfatophilum, doc^dChloropseudomonas 

 ethylicum. Figs, 1-3 pertain to chromatophores suspended in distilled 

 water. The Chromatium chromatophores were donated by Dr. R, C, 

 Fuller. Figs. 4 and 5, for whole cells, were submitted by Dr. J, M, 

 Olson. The relative heights of the bands at 800, 850, and 870 to 890 m/i 

 in Rps. spheroides and Chromatium vary considerably according to 

 the culture conditions. 



Rhodospiri Hum rubrum 



400 



500 600 700 800 

 WAVELENGTH in m^ 



900 



Fig. 1. Ahsorptionspectrumof RJiodospirillio)! r/<6n/o?, strain S-1. Solid curve, 

 chromatophores in water. Dotted curve, the same concentration of BChl in 

 acetone /methanol, 7 vol/2 vol. A blue-green mutant of R. rubru))!, isolated by 

 Dr. J. W. Newton, has essentially the same near-infrared spectrum. 



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