Anabaena
•Anabaena are found in areas such as freshwater lakes, brackish seas and paddy fields etc
•Anabaena is known for its heterocyst’s, Gas vesicles, and secretion of select compounds. They are often called ‘blue-green algae’ due to its colour and it often blooms at optimal conditions.
•Heterocyst's are able to fix nitrogen.
•Heterocyst's developed with rising oxygen levels globally so that nitrogen fixation was able to continue as it requires an anoxic environment.
•Photosynthesis occurrence is located within the vegetative cells
•The heterocyst’s are connected to the vegetative cells and work in a mutualistic manner with each other
•Anabaena is also known for secreting select biochemical compounds to aid in its survival.
•This can be to interact with themselves to help regulate growth, with other organisms that surround them or to help fight off any threats to themselves such as other forms of cyanobacteria.
•Some compounds that they secrete include Antiviral, antibacterial and allelochemicals which can help defend and inhibit growth of surrounding organism’s so that it can flourish itself
These compounds can be toxic to the surrounding environment and so becomes a problem for local animals and other wildlife
•When nitrogen levels drop in the environment, it is also adapted by having storage molecules known as cyanophycin which is a nitrogen storage product. This can be broken down and used so normal processed may continue.
•This can also be used as a resource for when there is a lack of light as it can be used to produce ATP by arginine being broken down into ornithine.
•Gas vesicles allow the Anabaena to change its buoyancy for example within water so that it can effectively harness a optimal amount of light.
•This leads to blooms of Anabaena appearing as they fight for optimal photosynthesis conditions in nutrient rich lakes
•Gas vesicles can also take the Anabaena to go lower into the water under high light intensities so that optimal conditions remain
•Anabaena also contains a gene for RNA helicase which is induced when temperatures decrease. It is thought that CrhC gene might be involved in translocation of proteins across the membrane which is activated at low temperatures.
•They have a thick cell wall and germinate if the outer cell wall is broken down.
•It has ‘resting spores or akinetes’ that form to help combat changing temperatures
