Search results
Results From The WOW.Com Content Network
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 ...
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 .
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]
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]
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
In animals, the plasma membrane is the outer boundary of the cell, while in plants and prokaryotes it is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of phospholipids , which are amphiphilic (partly hydrophobic and partly hydrophilic ).