“…Certain strains of R. sphaeroides (216,218,239) and R. capsulata (277) lack functional reaction center bacteriochlorophyll (P870), whereas they synthesize the light-harvesting (bulk) bacteriochlorophyll. Accordingly, such mutants do not manifest those activities associated with the primary photochemistry of photosynthetic cells (211,218,220). Mutants of R. rubrum have also been reported with properties characteristic of strains with defective reaction centers (44,181).…”