A CIRCADIAN RHYTHM IN CELL DIVISION IN A PROKARYOTE, THE CYANOBACTERIUM SYNECHOCOCCUS WH7803 1

@article{Sweeney1989ACR,
  title={A CIRCADIAN RHYTHM IN CELL DIVISION IN A PROKARYOTE, THE CYANOBACTERIUM SYNECHOCOCCUS WH7803 1},
  author={Beatrice Marcy Sweeney and M. Beatriz Borgese},
  journal={Journal of Phycology},
  year={1989},
  volume={25}
}
Circadian rhythms are common in eukaryotes, but the several claimed cases in prokaryotes are all open to alternative interpretation. We report here a clearcut circadian rhythm in cell division in a marine Synechococcus sp. strain WH7803, under conditions where the generation time is longer than one day, that is entrained by a light–dark cycle, and that persists for at least four cycles in continuous light (2 μE·m−2·s−1) and constant temperature (22, 20 or 16°C) with a maximum in dividing cells… 
Biological clock in the prokaryote Synechococcus RF-1
TLDR
The prokaryote Synechococcus RF-1 exhibits circadian rhythms of nitrogen fixation and leucine uptake after being entrained in a diurnal light/dark regimen, and a “clock” consisting of a molecular complex which can respond differentially to different induction conditions is hypothesized.
CYANOBACTERIAL CIRCADIAN RHYTHMS.
TLDR
The promise of cyanobacteria as simple models for elucidating the biological clock mechanism is being fulfilled, as mutants affected in period, rhythm generation, and rhythm amplitude, isolated through the use of real time reporters of gene expression, have implicated genes involved in these aspects of the clock.
CIRCADIAN RHYTHM IN GROWTH AND DEATH OF ANABAENA FLOS‐AQUAE (CYANOBACTERIA)
TLDR
Cell growth and death in A. flos‐aquae appear to be under the control of circadian clocks, and thus it seems that their death is programmed cell death.
Circadian Rhythm of the Prokaryote Synechococcus sp. RF-1.
TLDR
Because the endogenous rhythm of nitrogen fixation was not affected by a phase-shift of its previous cycles, the circadian rhythm in Synechococcus sp.
A cyanobacterial circadian timing mechanism.
TLDR
The mechanism of the cyanobacterial circadian clock that is emerging is based principally on the assembly and disassembly of a large complex at whose heart are the proteins KaiA, KaiB, and KaiC, which employ protein domains that are similar to those in two-component regulatory systems of bacteria.
The itty-bitty time machine genetics of the cyanobacterial circadian clock.
TLDR
Undoubtedly, continued genetic and mutational analyses of this single-celled cyanobacterium will aid in teasing out the intricacies of the Kai-based circadian clock to advance the understanding of this system as well as other more "complex" systems.
Biochemical Evidence for a Timing Mechanism in Prochlorococcus
TLDR
It is demonstrated here that the remaining Kai proteins fulfill their known biochemical functions, although KaiC is hyperphosphorylated by default in this system, consistent with a model in which a mechanism that is less robust than the well-characterized KaiABC protein clock of Synechococcus is sufficient for biological timing in the very stable environment that Prochlorococcus inhabits.
Cell Division Cycles and Circadian Rhythms
TLDR
Whether the cyanobacterial cells are rapidly growing or halted in their division cycle, the circadian clock appears to tick steadily and operates normally, which implies an independence of circadian timekeeping from the cell division cycle.
The circadian clock in the prokaryote Synechococcus RF-1
TLDR
The prokaryote is structurally and functionally simpler than the eukaryote and therefore it is potentially a useful model system for studying the control mechanism of circadian rhythms, and the physiological properties of circadian rhythm have been well characterized.
Diversity of KaiC-based timing systems in marine Cyanobacteria.
TLDR
This review summarizes data on the model circadian clock from S. elongatus PCC 7942 and compares it to the reduced clock system of the marine cyanobacterium Prochlorococcus marinus MED4.
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 10 REFERENCES
Dinitrogen-fixing endogenous rhythm in Synechococcus RF-1
TLDR
Under continuous illumination this unicellular aerobic cyanobacterium fixes dinitrogen continuously at a variable and usually low rate, which appears to be the first record of an endogenous rhythm in a prokaryote.
Rhythmic Cell Division in Populations of Gonyaulax polyedra
TLDR
The occurrence of a glow, or steady light emission of low intensity, at about the time ofcell division is described, and it is suggested that this glow may result from cellular changes accompanying certain stages of cell division.
Circadian rhythms in unicellular organisms: an endeavor to explain the molecular mechanism.
TLDR
This chapter discusses the circadian rhythms in unicellular organisms and the molecular mechanisms of circadian-time measurement, which are among the basic regulatory phenomena in biology whose mechanisms are essentially unknown.
Growth synchrony and cellular parameters of the unicellular nitrogen‐fixing marine cyanobacterium, Synechococcus sp. strain Miami BG 043511 under continuous illumination
TLDR
Data indicate that this unicellular cyanobacterium can grow diazotrophically under conditions of continuous illumination by the segregation of photosynthesis and nitrogen fixation within a cell division cycle.
Diel patterns of cell division in marine Synechococcus spp. (Cyanobacteria): use of the frequency of dividing cells technique to measure growth rate
TLDR
Growth rates of oceanic populations exhibiting diel patterns in FDC were found to range from 0.42 to 0.86 d-l, and these values exceed previous estimates of phytoplankton growth rates in oligotrophic regions.
Strategy by which nitrogen-fixing unicellular cyanobacteria grow photoautotrophically
TLDR
Novel strains of aerobic nitrogen-fixing, unicellular marine cyanobacteria, Synechococcus spp.
Effects of light intensity and nutrient availability on diel patterns of cell metabolism and growth in populations of Synechococcus spp.
TLDR
Rates of cell division estimated from the percentage of dividing cells in preserved samples were 0.83 divisions d-1 in surface warm-core eddy populations, supporting the view that carbon and nitrogen turnover rates in oligotrophic waters can be sufficient to promote near optimal growth of Synechococcus spp.
New type of N2-fixing unicellular cyanobacterium (blue-green alga)
A new N2-fixing unicellular cyanobacterium identified as a Synechococcus sp. was isolated and purified as an axenic culture. It fixed N2 aerobically either under continuous illumination or in
Studies of marine planktonic diatoms. I. Cyclotella nana Hustedt, and Detonula confervacea (cleve) Gran.
Bacteria-free clones of the small centric diatom Cyclotella nana Hustedt were isolated, three from estuarine localities, one from Continental Shelf waters, and one from the Sargasso Sea. Detonula
Membrane model for the circadian clock
TLDR
The biological clock may be a feedback system involving ions and ion-transport channels involved in ion transport and excites the response of the immune system.