394 PHOTOMECHANICAL CONSIDERATIONS 



21. Klingenberg, M., MuUer, A., Schmidt- Mende, P., and Witt, H. T., Changes 

 in absorption during photosynthesis in the ultra-violet spectrum. Nature, 

 194, 379-380 (1962). 



22. San Pietro, A., Photochemical reduction of triphosphopyridine nucleotide 

 by illuminated chloroplasts. In Light and Life, W. D. McElroy and B. Glass, 

 eds., The Johns Hopkins Press, Baltimore, 1961, pp. 631-642. 



23. Bishop, N. I., The possible role of plastoquinone (Q-254) in the electron 

 transport system of photosynthesis. In Ciba Foundation Symposium on 

 Quinones in Electron Transport, G. E. W. Wolstenholme and C. M. O'Con- 

 nor, eds., J. and A. Churchill, Ltd., London, 1961, pp. 385-404. 



24. Duysens, L. N. M., Transfer of excitation energy in photosynthesis. Thesis, 

 Utrecht, 1952. 



25. Goedheer, J. C, Spectral and redox properties of bacteriochlorophyll in its 

 natural state. Biochim. Biophys . Acta, 38, 389-399 (1960). 



26. Arnold, W., and Clayton, R. K., The first step in photosynthesis: evidence 

 for its electronic nature. Proc. Natl. Acad. Sci. U. S., 46, 769-776 (1960). 



27. Clayton, R. K., Primary reactions in bacterial photosynthesis. I. The nature 

 of light-induced absorbancy changes in chromatophores; evidence for a 

 special bacteriochlorophyll component. PJiotochem. Photobiol., 1, 201-210 

 (1962). 



28. Clayton, R. K., Primary reactions in bacterial photosynthesis. II. The 

 quantum requirement for bacteriochlorophyll conversion in the chromato- 

 phore. Photochem. Photobiol., 1, 305-311 (1962). 



29. Clayton, R. K., Primary reactions in bacterial photosynthesis. III. Reactions 

 of carotenoids and cytochromes in illuminated bacterial chromatophores. 

 Photochem. Photobiol., 1,313-323 (1962). 



30. Clayton, R. K., Evidence for the photochemical reductionof Coenzyme Q in 

 chromatophores of photosynthetic bacteria. Biochem. Biophys. Res. Com- 

 mun., 9, 49-53 (1962). 



31. Smith, L. ,Baltscheffsky, M.,and Olson, J. M., Absorption spectrum changes 

 observed on illumination of aerobic suspensions of photosynthetic bacteria. 

 J. Biol. Chem., 235, 213-218 (1960). 



32. Olson, J. M., and Chance, B., Oxidation-reduction reactions in the photosyn- 

 thetic bacterium Chromatium. I. Absorption spectrum changes in whole 

 cells. Arc/?. Biochem. Biophys., 88, 26-39 (1960). 



33. Vredenberg, W. J., and Duysens, L. N. M., Transfer of energy from bac- 

 teriochlorophyll to a reaction centre during bacterial photosynthesis. 

 Nature, 197, 355-357 (1963). 



34. Olson, J. M., and Kok, B., Is oxidized bacteriochlorophyll an intermediate 

 in bacterial photosynthesis? Biochem. Biophys. Acta, 32, 278-280 (1959). 



35. Chance, B., and Nishimura, M., On the mechanism of chlorophyll-cytochrome 

 interaction: The temperature insensitivity of light-induced cytochrome 

 oxidation in Chromatium. Proc. Natl. Acad. Sci. U. S., 46, 19-24 (1960). 



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

 bacterium. Science, 135, 101 (1962). 



37. Duysens, L. N. M., Huiskamp, W. J., Vos, J. J., and van der Hart, J. M., 

 Reversible changes in bacteriochlorophyll in purple bacteria upon illumina- 

 tion. Biochim. Biophys. Acta, 19, 188-190 (1956). 



38. Clayton, R. K., Toward the isolation of a photochemical reaction center in 

 Rhodopseudomonas spheroides . Biochi)n. Biophys. Acta, in press (1963). 



39. Arnold, W.,and Sherwood, H. K., Are chloroplasts semiconductors? Proc. 

 Natl. Acad. Sci. U. S., 43, 105-114 (1957). 



40. Arnold, W., and Sherwood, H. K., Energy storage in chloroplasts. J. Phys. 

 Chem., 63, 2-4 (1959). 



