scholarly journals Diurnal Regulation of In Vivo Localization and CO2-Fixing Activity of Carboxysomes in Synechococcus elongatus PCC 7942

Life ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 169
Author(s):  
Yaqi Sun ◽  
Fang Huang ◽  
Gregory F. Dykes ◽  
Lu-Ning Liu
Keyword(s):  
Carbon Fixation ◽  
Natural Habitat ◽  
Synechococcus Elongatus ◽  
Confocal Imaging ◽  
Dark Phase ◽  
Dynamic Regulation ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942 ◽  
Diurnal Regulation

Carboxysomes are the specific CO2-fixing microcompartments in all cyanobacteria. Although it is known that the organization and subcellular localization of carboxysomes are dependent on external light conditions and are highly relevant to their functions, how carboxysome organization and function are actively orchestrated in natural diurnal cycles has remained elusive. Here, we explore the dynamic regulation of carboxysome positioning and carbon fixation in the model cyanobacterium Synechococcus elongatus PCC 7942 in response to diurnal light-dark cycles, using live-cell confocal imaging and Rubisco assays. We found that carboxysomes are prone to locate close to the central line along the short axis of the cell and exhibit a greater preference of polar distribution in the dark phase, coupled with a reduction in carbon fixation. Moreover, we show that deleting the gene encoding the circadian clock protein KaiA could lead to an increase in carboxysome numbers per cell and reduced portions of pole-located carboxysomes. Our study provides insight into the diurnal regulation of carbon fixation in cyanobacteria and the general cellular strategies of cyanobacteria living in natural habitat for environmental acclimation.

scholarly journals Plasmid supercoiling decreases during the dark phase in cyanobacteria: a clarification of the interpretation of chloroquine-agarose gels.

2021 ◽  
Author(s):  
Salima Rüdiger ◽  
Anne Rediger ◽  
Adrian Kölsch ◽  
Dennis Dienst ◽  
Ilka Maria Axmann ◽  
...  
Keyword(s):  
Topoisomerase I ◽  
Metabolic Flux ◽  
Dna Supercoiling ◽  
Dark Phase ◽  
Agarose Gels ◽  
Open Issue ◽  
Negative Supercoiling ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

In cyanobacteria DNA supercoiling varies over the diurnal light/dark cycle and is integrated with the circadian transcription program and (Woelfle et al. [2007], Vijayan et al. [2009], PNAS). Specifically, Woelfle et al. have reported that DNA supercoiling of an endogenous plasmid became progressively higher during prolonged dark phases in Synechococcus elongatus PCC 7942. This is counterintuitive, since higher levels of negative DNA supercoiling are commonly associated with exponential growth and high metabolic flux. Vijayan et al. then have reverted the interpretation of plasmid mobility on agarose gels supplemented with chloroquine diphosphate (CQ), but not further discussed the differences. Here, we set out to clarify this open issue in cyanobacterial DNA supercoiling dynamics. We first re-capitulate Keller's band counting method (1975, PNAS) using CQ instead of ethidium bromide as the intercalating agent. A 500x-1000x higher CQ concentration is required in the DNA relaxation reaction (topoisomerase I) than in the agarose gel buffer to quench all negative supercoiling of pUC19 extracted from Escherichia coli. This is likely due to the dependence of both, the DNA binding affinity of CQ and the induced DNA unwinding angle, on the ionic strength of the buffer. Lower levels of CQ were required to fully relax in vivo pUC19 supercoiling than were used by Woelfle et al. Next, we analyzed the in vivo supercoiling of endogenous plasmids of Synechocystis sp. PCC 6803, at two different CQ concentrations. This clearly indicates that negative supercoiling of plasmids does not increase but decreases in the dark phase, and progressively decreases further in prolonged darkness.

scholarly journals Photophysiological and Photosynthetic Complex Changes during Iron Starvation in Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e59861 ◽  
Author(s):  
Jared M. Fraser ◽  
Sarah E. Tulk ◽  
Jennifer A. Jeans ◽  
Douglas A. Campbell ◽  
Thomas S. Bibby ◽  
...  
Keyword(s):  
Synechococcus Elongatus ◽  
Iron Starvation ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942 ◽  
Synechocystis Sp ◽  
Pcc 6803

Stability of the Synechococcus elongatus PCC 7942 circadian clock under directed anti-phase expression of the kai genes

Microbiology ◽  
2005 ◽  
Vol 151 (8) ◽  
pp. 2605-2613 ◽  
Author(s):  
Jayna L. Ditty ◽  
Shannon R. Canales ◽  
Breanne E. Anderson ◽  
Stanly B. Williams ◽  
Susan S. Golden
Keyword(s):  
Circadian Clock ◽  
Expression Patterns ◽  
Phase Relationship ◽  
Synechococcus Elongatus ◽  
Cycle Period ◽  
Rhythmic Expression ◽  
Core Components ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Time Required ◽  
Pcc 7942

The kaiA, kaiB and kaiC genes encode the core components of the cyanobacterial circadian clock in Synechococcus elongatus PCC 7942. Rhythmic expression patterns of kaiA and of the kaiBC operon normally peak in synchrony. In some mutants the relative timing of peaks (phase relationship) between these transcription units is altered, but circadian rhythms persist robustly. In this study, the importance of the transcriptional timing of kai genes was examined. Expressing either kaiA or kaiBC from a heterologous promoter whose peak expression occurs 12 h out of phase from the norm, and thus 12 h out of phase from the other kai locus, did not affect the time required for one cycle (period) or phase of the circadian rhythm, as measured by bioluminescence reporters. Furthermore, the data confirm that specific cis elements within the promoters of the kai genes are not necessary to sustain clock function.

scholarly journals Putative extracellular α-class carbonic anhydrase, EcaA, of Synechococcus elongatus PCC 7942 is an active enzyme: a sequel to an old story

Microbiology ◽  
2018 ◽  
Vol 164 (4) ◽  
pp. 576-586 ◽  
Author(s):  
Elena V. Kupriyanova ◽  
Maria A. Sinetova ◽  
Vladimir S. Bedbenov ◽  
Natalia A. Pronina ◽  
Dmitry A. Los
Keyword(s):  
Carbonic Anhydrase ◽  
Synechococcus Elongatus ◽  
Active Enzyme ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942

scholarly journals Role of KaiC phosphorylation in the circadian clock system of Synechococcus elongatus PCC 7942

2004 ◽  
Vol 101 (38) ◽  
pp. 13927-13932 ◽  
Author(s):  
T. Nishiwaki ◽  
Y. Satomi ◽  
M. Nakajima ◽  
C. Lee ◽  
R. Kiyohara ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Synechococcus Elongatus ◽  
Clock System ◽  
Synechococcus Elongatus Pcc 7942 ◽  
Pcc 7942
Sign in / Sign up

Export Citation Format

Share Document