Effect of dissolved inorganic carbon on the expression of carboxysomes, localization of Rubisco and the mode of inorganic carbon transport in cells of the cyanobacterium Synechococcus UTEX 625

In the cyanobacterium Synechoccoccus UTEX 625, the extent of expression of carboxysomes appeared dependent on the level of inorganic carbon (CO2 + HCO3(-) in the growth medium. In cells grown under 5% CO2 and in those bubbled with air, carboxysomes were present in low numbers (< 2.longitudinal se...

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Bibliographic Details
Published in:Archives of microbiology 1993, Vol.159 (1), p.21-29
Main Authors: McKay, R.M.L, Gibbs, S.P, Espic, G.S
Format: Article
Language:English
Subjects:
Bacteriology
bicarbonates
Biogenesis of cell structures, supramolecular organization
Biological and medical sciences
carbon dioxide
cytoplasmic inclusions
dissolved inorganic carbon
Fundamental and applied biological sciences. Psychology
ion transport
Microbiology
photosynthesis
ribulose-bisphosphate carboxylase
Synechococcus
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Summary:In the cyanobacterium Synechoccoccus UTEX 625, the extent of expression of carboxysomes appeared dependent on the level of inorganic carbon (CO2 + HCO3(-) in the growth medium. In cells grown under 5% CO2 and in those bubbled with air, carboxysomes were present in low numbers (< 2.longitudinal section-1) and were distributed in an apparently random manner throughout the centroplasm. In contrast, cells grown in standing culture and those bubbled with 30 microliter CO2.l-1 possessed many carboxysomes (> 8.longitudinal section-1). Moreover, carboxysomes in these cells were usually positioned near the cell periphery, aligned along the interface between the centroplasm and the photosynthetic thylakoids. This arrangement of carboxysomes coincided with the full induction of the HCO3(-) transport system that is involved in concentrating inorganic carbon within the cells for subsequent use in photosynthesis. Immunolocalization studies indicate that the Calvin cycle enzyme ribulose bisphosphate carboxylase was predominantly carboxysome-localized, regardless of the inorganic carbon concentration of the growth medium, while phosphoribulokinase was confined to the thylakoid region. It is postulated that the peripheral arrangement of carboxysomes may provide for more efficient photosynthetic utilization of the internal inorganic carbon pool in cells from cultures where carbon resources are limiting.
ISSN:0302-8933
1432-072X
DOI:10.1007/bf00244259