422 PHOTOMECHANICAL CONSIDERATIONS 



ACKNOWLEDGMENTS 



We thank Miss E. N. Kondrat'eva of Moscow University for giving us a cul- 

 ture oiChloropscudo)noiias efliylici(})i. This work was carried out at Brookhaven 

 National Laboratory mider the auspices of the U. S. Atomic Energy Commission. 



REFERENCES 



1. Duysens, L. N. M., Transfer of Excitation Energy in Photosynthesis. Thesis, 

 State University, Utrecht, 1952. 



2. Duysens, L. N. M., Reversible photooxidation of a cytochrome pigment in 

 photosynthesizing RliodospirillitDi nibrKiii. Nature, 173, 692 (1954). 



3. Chance, B., and Smith, L., Respiratory pigments of RJioflospiriUitiii rnhnn)i. 

 Nature, 175, 803 (1955). 



4. Smith, L., and Ramirez, J., Absorption spectrum changes in photosynthetic 

 bacteria following illumination or oxygenation. A rc/z. Biochem. Biophys., 

 79, 233 (1959). 



5. Olson, J. M., and Chance, B., Oxidation-reduction reactions in the photo- 

 synthetic bacterium CIironiatiuDi. Arch. Biocheui. Biophys., 88, 26 (1960). 



6. Clayton, R. K., Reactions of carotenoids and cytochromes in illuminated 

 bacterial chromatophores. Photochem. Photobiol., 1, 313 (1962). 



7. Olson, J. M., and Morita, S., Light-induced absorbancy changes in Rhodo- 

 iiiicrobii(i)/ vaiDiiclUi. This volume, p. 433. 



8. Gibson, J., Cytochrome pigments from the green photosynthetic bacterium 

 Chlorohium thiosulphatophilum. Biochem. J., 79, 151 (1961). 



9. Olson, J. M., Filmer, D., RadlofL R., Romano, C, and Sybesma, C, The 

 protein-chlorophyll-770 complex from green bacteria. This volvune, p. 423. 



10. Kondrat'eva, E. N., and Moshentseva, L. V., Pigments of the green sulfur 

 bacterium ChloropseudoinoJias cthvlicinii. Dokl. Akad. Nauk SSSR, 135, 

 460 (1960). 



11. Stanier, R. Y., and Smith, J. H. C, The chlorophylls of green bacteria. 

 Biochim. Biophys. Acta, 41, 478 (1960). 



12. Sybesma, C, and Olson, J. M., Transfer of chlorophyll excitation energy in 

 green photosynthetic bacteria. Proc. Natl. Acad. Sci., U. S., 49, 248 (1963). 



13. Krasnovskii, A. A., Erokhin, Yu. E., and Yui-Tsun, Kh., Fluorescence of 

 aggregated forms of bacteriochlorophyll, bacterioviridin, and chlorophyll 

 in relation to the state of the pigments in photosynthetic organisms. Dokl . 

 Akad. Nauk SSSR, 143, 456 (1962). 



14. Olson, J. M., Quantum efficiency of cytochrome oxidation in a photosynthetic 

 bacterium. Science, 135, 101 (1962). 



15. Forster, T., Zwischenmolekularen Energiewanderung und Fluoreszenz. 

 Ann. der Physik, 2, 55 (1948). 



16. Sybesma, C, unpublished. 



17. Fuller, R. C, The photochemical structures of the green and purple sulfur 

 bacteria. This volume, p. 000. 



Note added in proof . Recent experiments (Sybesma, C, and Vre- 

 denberg, W. J., Biochim. Biophys. Acta, in press) indicate that 

 excitation energy is further transferred from chlorophyll-770 to 

 a reaction center having an absorption maximum at 840 m^u. 



