The purple nonsulfur bacterium Rhodospirillum rubrum has been employed to study physiological adaptation to limiting oxygen tensions (microaerophilic conditions). R. rubrum produces maximal levels of photosynthetic membranes when grown with both succinate and fructose as carbon sources under microaerophilic conditions in comparison to the level (only about 20% of the maximum) seen in the absenc...

The details of this condensation and the mechanisms involved were not elucidated until very recently. In the last few months, several laboratories have independently reported their preliminary findings demonstrating the enzymatic synthesis of 6aminolevulinic acid. We have found that particle-free extracts of Rhodopseudomonas spheroides and Rhodosp&%llum rubrum cells grown anaerobically in the l...

Lifetime of the excited state (tau) of bacteriochlorophyll (BChl) in photosynthetic bacteria, measured with a mode-locked argon laser (oscillating at 488 nm; mode locked at 56 MHz) as light source, ranged from 0.3 to 2.5 nsec. These tau values are reported with a precision of +/-0.1 nsec. The value of tau at high exciting light intensity (I) was two to three times that at low intensity. For you...

The involvement of heme proteins in photometabolism, first suggested by Hill (1, 2), seems certain from results of recent enzyme studies (3-5) and observations on systems in viva using differential spectrophotometry (6-10). Of the many heme proteins which exist in intimate association with the photoactive pigments in the functional subcellular structures of photosynthetic tissues, only three ha...