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[1] [4] Once conditions become more favorable for growth, the akinete can then germinate back into a vegetative cell. [5] Increased light intensity, nutrients availability, oxygen availability, and changes in salinity are important triggers for germination. [5] In comparison to vegetative cells, akinetes are generally larger.
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc, Cylindrospermum, and Anabaena. [1] They fix nitrogen from dinitrogen (N 2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis. [2]
Hormogonia are motile filaments of cells formed by some cyanobacteria in the order Nostocales and Stigonematales. They are formed during vegetative reproduction in unicellular, filamentous cyanobacteria, and some may contain heterocysts and akinetes. [1] [2]
With optimal environmental conditions, Anabaena circinalis grow unchecked, forming large blooms that appear as a greenish slime at the surface of the water (fig. 2). In harsh conditions, A. circinalis form spore-like cells called akinetes. Akinetes are resistant to low temperature, desiccation, and darkness. Often, akinetes will hibernate in ...
Their cell size varies from less than 1 μm in diameter (picocyanobacteria) up to 100 μm (some tropical forms in the genus Oscillatoria) [39] [40] [41] Filamentous forms exhibit functional cell differentiation such as heterocysts (for nitrogen fixation), akinetes (resting stage cells), and hormogonia (reproductive, motile filaments). These ...
Over the winter Gloeotrichia forms dormant cells called akinetes that germinate and begin to form colonies when temperatures begin to increase. [7] As these cells grow, they uptake nutrients like P. However, they generally uptake more nutrients than they need and store it for later use for when they migrate to the nutrient deplete epilimnion.
Nostoc punctiforme is a species of filamentous cyanobacterium.Under non-limiting nutritional environmental conditions, its filaments are composed of photosynthetic vegetative cells; upon nutrient limitation, some of these cells undergo differentiation into heterocysts, akinetes or hormogonia.
These akinetes can persist in sediment for long periods of time, and are able to germinate once water temperatures rise to the appropriate level. [2] The bacteria prefers temperatures ranging from 25–30 °C, light intensity of 80–121 μmol m-2 s-1, and a max salinity concentration of 4 g L-1 NaCl. The levels of the bacteria typically stay ...