Pseudomonas radiora

In Methylobacterium radiotolerans (previously, Pseudomonas radiora), spirilloxanthin is the dominant component in the RC-LHI complex (Saitoh et al., 1995), while carotenoic acids are found in the outer membranes accompanied by no BChls and have nophotosynthetic functions (S. Saitoh, personal communication). Two species of Methylobacterium have also similar carotenoic acids with M radiotolerans, and two species of the forth group described above have polar carotenoids, diapocarotenoic acid derivatives. These highly polar carotenoids in the third, the forth and the fifth groups may be nonphotosynthetic carotenoids, which are not bound to the photosynthetic pigment-protein complexes (Shimada, 1995). Although their functions are not known, there is the possibility that they protect the photosynthetic apparatus from the outside aerobic conditions. 

Saitoh S, Takaichi S, Shimada K and Nishimura Y (1995) Identification and subceUular distribution of carotenoids in the aerobic photosynthetic bacterium. Pseudomonas radiora strain MD-1. Plant Cell Physiol 36 819-823 Saitoh S, Suzuki T and Nishimura Y (1998) Proposal of Craurococcus roseus gen. nov., sp. nov. and Paracraurococcus ruber gen. nov., sp. nov., novel aerobic bacteriochlorophyU a-containing bacteria from soil. Int J Syst Bacterid 48 1043-1047... 

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