IGEM:IMPERIAL/2009/Brainstormings/bioclock

=Introduction=

cyanothece is the only cyanobacteria that can perform photosynthesis and nitrogen fixation in the same cell

quote: photosynthesis and nitrogen fixation are at odds with one another. Fixing nitrogen requires nitrogenase, but the oxygen produced by photosynthesis degrades nitrogenase, making nitrogen fixation difficult or impossible in photosynthetic organisms. this is because "respiration requires oxygen, the cells conveniently use up this by-product of photosynthesis, likely helping to protect nitrogenase from degradation. ".

quote : Cyanothece are of great interest because, even though one cell lives less than a day, dividing every 10 to 14 hours, together they have a biological clock, telling them when to do what over a 24-hour period. In fact, cyanobacteria are the only bacteria known to have a circadian behavior."

this article mainly focuses on the fact that cyanothece can be used to produce clean energy

here's the article about it

=interesting info=

1. clock can run without external stimuli

2. maintains a period of 24hours in constant conditions (12hrs light, 12 hrs dark)

3. can be reset by cycles of light and darkness

4. temperature invariant. clock works even when the ambient conditions change.

=feedback 17th July=

- Look into details of the output - Chassis? - Identify best points of the timer mechanism but change approach - Provide pathways: Clearer illustration of feedback, etc. - Paris last year project - General group feeling: Read a bit more about certain bits. V stable clock and low noise so some desirable properties. - James' suggestion: Missing translational control, more advantageous as compared to transcription (riboswitches) - Think of most desirable features to extract. - Maybe couple as part of the encapsulation

=papers=

1997 paper

[]

pg 4

pg 8 (last para)

pg14 onwards

paper on resetting the circadian cycle

circadian mechanisms in other living organisms

genes involved

another paper on mechanism

a little insight on how light is sensed by cyanobacterium