Other Definitions
hormogonium (dict)
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HormogoniumHormogonia are small, motile filaments formed by some cyanobacteria in the family Nostoceae. Cyanobacteria differentiate into hormogonia when exposed to an environmental stress or when placed in new media. Hormogonium differentiation is crucial for the development of nitrogen-fixing plant cyanobacteria symbioses, in particular that between cyanobacteria of the genus Nostoc and their hosts. In response to a hormogonium-inducing factor (HIF) secreted by plant hosts, cyanobacterial symbionts differentiate into hormogonia and then dedifferentiate back into vegetative cells after about 96 hours. Hopefully, they have managed to reach the plant host by this time. The bacteria then differentiate specialized nitrogen-fixing cells called heterocysts and enter into a working symbiosis with the plant.
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