This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mohamed, H. E. Articles by Vermaas, W. F. J. Search for Related Content PubMed PubMed Citation Articles by Mohamed, H. E. Articles by Vermaas, W. F. J.

Myxoxanthophyll Is Required for Normal Cell Wall Structure and Thylakoid Organization in the Cyanobacterium Synechocystis sp. Strain PCC 6803

School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, Arizona 85287-4501

Received 1 December 2004/ Accepted 4 August 2005

Myxoxanthophyll is a carotenoid glycoside in cyanobacteria that is of unknown biological significance. The sugar moiety of myxoxanthophyll in Synechocystis sp. strain PCC 6803 was identified as dimethyl fucose. The open reading frame sll1213 encoding a fucose synthetase orthologue was deleted to probe the role of fucose and to determine the biological significance of myxoxanthophyll in Synechocystis sp. strain PCC 6803. Upon deletion of sll1213, a pleiotropic phenotype was obtained: when propagated at 0.5 µmol photons m^–2 s^–1, photomixotrophic growth of cells lacking sll1213 was poor. When grown at 40 µmol photons m^–2 s^–1, growth was comparable to that of the wild type, but cells showed a severe reduction in or loss of the glycocalyx (S-layer). As a consequence, cells aggregated in liquid as well as on plates. At both light intensities, new carotenoid glycosides accumulated, but myxoxanthophyll was absent. New carotenoid glycosides may be a consequence of less-specific glycosylation reactions that gained prominence upon the disappearance of the native sugar moiety (fucose) of myxoxanthophyll. In the mutant, the N-storage compound cyanophycin accumulated, and the organization of thylakoid membranes was altered. Altered cell wall structure and thylakoid membrane organization and increased cyanophycin accumulation were also observed for slr0940K, a strain lacking -carotene desaturase and thereby all carotenoids but retaining fucose. Therefore, lack of myxoxanthophyll and not simply of fucose results in most of the phenotypic effects described here. It is concluded that myxoxanthophyll contributes significantly to the vigor of cyanobacteria, as it stabilizes thylakoid membranes and is critical for S-layer formation.

This article has been cited by other articles:

• Kilian, O., Steunou, A.-S., Fazeli, F., Bailey, S., Bhaya, D., Grossman, A. R. (2007). Responses of a Thermophilic Synechococcus Isolate from the Microbial Mat of Octopus Spring to Light. Appl. Environ. Microbiol. 73: 4268-4278 [Abstract] [Full Text]  
• Mohamed, H. E., Vermaas, W. F. J. (2006). Sll0254 (CrtLdiox) Is a Bifunctional Lycopene Cyclase/Dioxygenase in Cyanobacteria Producing Myxoxanthophyll. J. Bacteriol. 188: 3337-3344 [Abstract] [Full Text]