Unusual spirilloxanthin pathway

When one enzyme of the normal spirilloxanthin pathway is lacking or is present with reduced activity, the composition will be expected to change. Some species have indeed been reported to have such unusual compositions (Tables 3-5). Lycopene is 

Unusual-Spirillo Unusual-Spirillo Spirilloxanthin, carotenal G Spirilloxanthin G Spirilloxanthin G Spirilloxanthin G Spirilloxanthin Unusual-Spirillo 

2761 =DSM 109 Unusual-Spirillo lycopene (37), rhodopin (16), anhydrorhodovibrin (32), rhodovibrin (7), spirilloxanthin (8) 1 

Genus (abbreviation) Species strain Ca rote nogenes is type Carotenoids (% of total) Ref. No. 

This genus has recently been reclassified (Imhoff et al., 1998b). 

---

This spheroidene pathway is a variant of the unusual spirilloxanthin pathway as a result of the different properties of the phytoene desaturases (CrtI). 

Only the spirilloxanthin pathway is found (Tables 1 and 5). Some species have the unusual spirilloxanthin pathway. Hlr. halochloris and Hlr. abdel-malekii contain in addition carotenoid glycosides and their esters as major components. 

The Rhodospirillaceae and Chromatiaceae have the spirilloxanthin or the okenone pathway depending on the genus or species. All of the Ectothiorhodospiraceae have the spirilloxanthin pathway. The isorenieratene, the y-and -carotene, and the diapocarotene pathways are found specifically in the Chlorobiaceae, Chloroflexaceae, and Heliobacteriaceae, respectively. Aerobic photosynthetic bacteria mostly have the spirilloxanthin pathway, further most of these species have unusual carotenoids including non-photosynthetic carotenoids, such as carotenoid sulfates and carotenoic acids, which have no photosynthetic functions. 

Spirilloxanthin pathway (normal spirilloxanthin, unusual spirilloxanthin, spheroidene, and carotenal pathways). 

Most of the aerobic photosynthetic bacteria so far desaibed have the spirilloxanthin pathway, further some also have unusual carotenoids as described below. 

The Chromatiaceae have either the spirilloxanthin pathway (normal spirilloxanthin, unusual spirilloxanthin and carotenal pathways) or okenone of the okenone pathway except for one species, Tea. halophila, which has both pathways (Tables 1 and4). Even in the same genus, some species have the spirilloxanthin pathway and others have the okenone pathway. Therefore, the carotenogenesis pathways are not well related to the bacteria s classification in the Chromatiaceae. 

---