Archives of Microbiology

, Volume 159, Issue 1, pp 21–29

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

  • R. Michael L. McKay
  • Sarah P. Gibbs
  • George S. Espie
Original Papers

DOI: 10.1007/BF00244259

Cite this article as:
McKay, R.M.L., Gibbs, S.P. & Espie, G.S. Arch. Microbiol. (1993) 159: 21. doi:10.1007/BF00244259


In the cyanobacterium Synechococcus UTEX 625, the extent of expression of carboxysomes appeared dependent on the level of inorganic carbon (CO2+HCOinf3sup-) 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 μl CO2 · 1-1 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 HCOinf3sup-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.

Key words

CyanobacteriaSynechococcusCarboxysomesRibulose bisphosphate carboxylaseImmunogold localizationCO2/HCOinf3sup-transport





dissolved inorganic carbon (CO2+HCOinf3sup-+COinf3sup2-)




ribulose 1,5-bisphosphate

Rubisco LS

large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • R. Michael L. McKay
    • 1
  • Sarah P. Gibbs
    • 1
  • George S. Espie
    • 2
  1. 1.Department of BiologyMcGill UniversityMontréalCanada
  2. 2.Department of Botany, Erindale CollegeUniversity of TorontoMississaugaCanada
  3. 3.Institute of Marine ScienceUniversity of AlaskaFairbanksUSA