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Many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. [45] [46] The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. To break away from the parent colony, a ...
Cyanobacteria are variable in morphology, ranging from unicellular and filamentous to colonial forms. Filamentous forms exhibit functional cell differentiation such as heterocysts (for nitrogen fixation), akinetes (resting stage cells), and hormogonia (reproductive, motile filaments). These, together with the intercellular connections they ...
In the absence of antibiotics or other stressors, filamentation occurs at a low frequency in bacterial populations (4–8% short filaments and 0–5% long filaments in 1- to 8-hour cultures). [3] The increased cell length can protect bacteria from protozoan predation and neutrophil phagocytosis by making ingestion of cells more difficult.
Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern. They are one of four genera of cyanobacteria that produce neurotoxins, which are
Their function is to secrete plant metabolites. Some of these metabolites include: terpenoids, which have many functions related to defense, growth, and development [6] phenylpropanoids, which have a role in many plant pathways, such as secondary metabolites, stress response, and act as the mediators of plant interactions in the environment [7]
A notable symbiotic relationship is that of Anabaena azollae [a] cyanobacteria with Azolla plants. Anabaena reside on the stems and within leaves of Azolla plants. [8] The Azolla plant undergoes photosynthesis and provides fixed carbon for the Anabaena to use as an energy source for dinitrogenases in the heterocyst cells. [8]
The function of the cyanobiont depends on its host species. Abundant marine cyanobacteria in the genus Synechococcus form symbionts with dinoflagellates in the genera Ornithocercus, Histionesis and Citharistes, where it is hypothesized to benefit its host through the provision of fixed nitrogen in oligotrophic, subtropical waters. [24]
[1] [2] Although cyanobacteria metabolize photoautotrophically like eukaryotic plants, they have prokaryotic cell structure. Cyanophages can be found in both freshwater and marine environments. [ 3 ] Marine and freshwater cyanophages have icosahedral heads, which contain double-stranded DNA, attached to a tail by connector proteins. [ 4 ]