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A large, thick-walled, nitrogen-fixing cell that occurs at intervals along the filaments of certain cyanobacteria.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Biology) biology a special cell type found in cyanobacteria and responsible for fixing nitrogen
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈhɛt ər əˌsɪst)

one of the enlarged nitrogen-fixing cells along the filaments in some blue-green algae.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
Mostly cyanobacteria protect nitrogenase from damage by intracellular oxygen by carrying out nitrogen fixation in morphologically and physiologically differentiated cells called heterocysts whereas photosynthesis takes place simultaneously in spatially separated vegetative cells [14-17].
A larger carcinoma lesion (lower and right corner) with some small lesions composed of tens of heterocysts (upper-left section) can be observed in Figure 3.
Fructose supports glycogen accumulation, heterocysts differentiation, N2 fixation and growth of the isolated cyanobiont Anabaena azollae.
These systems consist of a particular association of species with the measurement of morphological traits, such as, volume, maximum linear dimension, surface area and the presence of mucilage, flagella, aerotopes, heterocysts or siliceous structures.
Except for some groups, the diazotrophic (i.e., [N.sub.2]-fixing) cyanobacteria have specialized cells called heterocysts only where fixation of gaseous nitrogen is conducted under aerobic conditions.
Certain characteristics make some Cyanobacteria genera particularly suitable for blooming, such as presence of sheath and mucilage; specialized cells for nitrogen fixation (heterocysts) and resistance (akynetes); aerotopes; tolerance to large fluctuations in temperature; phosphorus storage capacity, among others (DOKULIL; TEUBNER, 2000).
They concluded that this may due to differences in the [N.sub.2] fixation potential in heterocysts.
The topics include the synchronization of chromosome dynamics and cell division in bacteria, protein subcellular localization, the cell biology of prokaryotic organelles, cyanobacterial heterocysts, biofilms, electron cryotomography, and single-molecule and super-resolution imaging in live bacteria cells.
Internationally, genetic improvement programs are heading towards the development of [F.sub.1] Papaya hybrids with the objective of exploiting heterocysts to increase yield.
Westiellopsis iyengarii, a Filaments with true branching; made of prostrate and erect systems, prostrate system multiseriate, erect system uniseriate; branches short, arising on both the sides: individual sheath around filaments absent; heterocysts intercalary, quadrate or cylindrical, was investigated for its protein and pigment contents at a rangeof different light intensities (low, medium and high) and qualities (Blue, Green and Red).