umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
DYNAMIC-RESPONSES OF PHOTOSYSTEM-II AND PHYCOBILISOMES TO CHANGING LIGHT IN THE CYANOBACTERIUM SYNECHOCOCCUS SP PCC-7942
Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).ORCID iD: 0000-0002-2147-7428
Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
1995 (English)In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 197, no 3, 553-562 p.Article in journal (Refereed) Published
Abstract [en]

We have examined the molecular and photosynthetic responses of a planktonic cyanobacterium to shifts in light intensity over periods up to one generation (7 h). Synechococcus sp. PCC 7942 possesses two functionally distinct forms of the D1 protein, D1:1 and D1:2. Photosystem II (PSII) centers containing D1:1 are less efficient and more susceptible to photoinhibition than are centers containing D1:2, Under 50 mu mol photons m(-2). s(-1), PSII centers contain D1:1, but upon shifts to higher light (200 to 1000 mu mol photons m(-2). s(-1)), D1:1 is rapidly replaced by D1:2, with the rate of interchange dependent on the magnitude of the light shift. This interchange is readily reversed when cells are returned to 50 mu mol photons m(-2). s(-1). If, however, incubation under 200 mu mol photons m(-2). s(-1) is extended, D1:1 content recovers and by 3 h after the light shift D1:1 once again predominates. Oxygen evolution and chlorophyll (Chi) fluorescence measurements spanning the light shift and D1 interchanges showed an initial inhibition of photosynthesis at 200 mu mol photons m(-2). s(-1), which correlates with a proportional loss of total D1 protein and a cessation of growth. This was followed by recovery in photosynthesis and growth as the maximum level of D1:2 is reached after 2 h at 200 mu mol photons m(-2). s(-1) Thereafter, photosynthesis steadily declines with the loss of D1:2 and the return of the less-efficient D1:1. During the D1:1/D1:2 interchanges, no significant change occurs in the level of phycocyanin (PC) and Chl a, nor of the phycobilisome rod linkers. Nevertheless, the initial PC/Chl a ratio strongly influences the magnitude of photoinhibition and recovery during the light shifts. In Synechococcus sp. PCC 7942, the PC/Chl a ratio responds only slowly to light intensity or quality, while the rapid but transient interchange between D1:1 and D1:2 modulates PSII activity to limit damage upon exposure to excess light.

Place, publisher, year, edition, pages
1995. Vol. 197, no 3, 553-562 p.
Keyword [en]
ACCLIMATION, D1 TURNOVER, PHOTOSYSTEM II, PHYCOBILISOME, SYNECHOCOCCUS SP PCC 7942, VARIABLE LIGHT
Identifiers
URN: urn:nbn:se:umu:diva-44719ISI: A1995TE42800016OAI: oai:DiVA.org:umu-44719DiVA: diva2:428120
Available from: 2011-06-29 Created: 2011-06-09 Last updated: 2017-12-11

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Gustafsson, PetterOquist, Gunnar
By organisation
Department of Plant PhysiologyUmeå Plant Science Centre (UPSC)
In the same journal
Planta

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 48 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf