Introduction to Cyanobacteria
- Cyanobacteria generate oxygen gas through oxygenic photosynthesis. Unlike purple sulfur bacteria or purple non-sulfur bacteria, cyanobacteria use chlorophyll a to gather light.
- Cyanobacteria live close to the surface of ponds, and have two major absorption bands between 550-620 due to phycobiliproteins.
Synechocystis sp 6803 Genetics
- Synechocystis carries multiple (6-12) copies of the genome in a single cell.
- Synechocystis has about 3,260 genes that code for proteins.
- Synechocystis is naturally transformable, i.e. it will uptake foreign DNA and incorporate this DNA into its genome by homologous recombination.
Synechocystis sp 6803 Growth
- The doubling time of Synechocystis is 12 hours (versus 20 minutes for E. coli), and it takes 7-10 days to get visible colonies of transformants on a plate.
- Liquid media: BG-11 media, Sigma catalog #, 500 mL of 50x ~$30
- Light intensity: 50-70 umol photons m2/s
- Temperature: 30-34 ºC
- pH: 8-10
Synechocystis sp 6803 Metabolism
- CO2 is assilimated through the Calvin cycle.
- Not fully functional citric acid cycle.
- Pentose phosphate is central pathway of carbohydrate metabolism.
- Gram negative (double membrane).
- Heterocysts form to fix nitrogen when NO3 and NH3 are absent.
Synechocystis sp 6803 Physiology
- Synechocystis is typically a slightly oblong spheriod, approximately 1.5 microns in diameter.