Heterocyst placement strategies to maximize the growth of cyanobacterial filaments

  title={Heterocyst placement strategies to maximize the growth of cyanobacterial filaments},
  author={Aidan I. Brown and Andrew D. Rutenberg},
  journal={Physical Biology},
Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria develop a regular pattern of heterocyst cells that fix nitrogen for the remaining vegetative cells. We examine three different heterocyst placement strategies by quantitatively modelling filament growth while varying both external fixed-nitrogen and leakage from the filament. We find that there is an optimum heterocyst frequency which maximizes the growth rate of the filament; the optimum frequency decreases as the… 
A storage-based model of heterocyst commitment and patterning in cyanobacteria
It is proposed that fN storage is an important component of heterocyst commitment and patterning in filamentous cyanobacteria and an integrated computational model of fN transport, cellular growth, and heterocySt commitment for filamentous Cyanobacteria is presented.
Formation and maintenance of nitrogen-fixing cell patterns in filamentous cyanobacteria
A theory that combines genetic, metabolic, and morphological aspects to understand this prokaryotic example of multicellularity, and finds that a purely stochastic initiation of the pattern, without a two-stage process, is enough to reproduce experimental observations.
The multicellular nature of filamentous heterocyst-forming cyanobacteria.
Various aspects of multicellularity in cyanobacterial filaments and their differentiation are reviewed, including filament architecture with emphasis on the structures used for intercellular communication.
Growth Characteristics of an Estuarine Heterocystous Cyanobacterium
A new estuarine filamentous heterocystous cyanobacterium was isolated from intertidal sediment of the Lagoa dos Patos estuary (Brazil). The isolate may represent a new genus related to
The evolution of mechanisms to produce phenotypic heterogeneity in microorganisms
It is shown that coordinated specialisation is more likely to evolve over random specialisation in well-mixed groups when: (i) social groups are small; (ii) helping is more “essential”; and (iii) there is a low metabolic cost to coordination.
Fixed nitrogen dynamics and heterocyst patterning in filamentous heterocystous cyanobacteria
The author states that the book was originally intended to be a collection of “short stories” but that “the stories began to take on a life of their own” after the second printing.
The evolution of mechanisms to divide labour in microorganisms 1
It is shown that fully coordinated specialisation is more likely to evolve over random specialisation in well-mixed groups when: (i) social groups are small; (ii) cooperation has a greater relative impact on fitness; and (iii) there is a relatively low metabolic cost to coordination.


Heterocyst patterns without patterning proteins in cyanobacterial filaments.
Reconciling cyanobacterial fixed-nitrogen distributions and transport experiments with quantitative modelling
The variations seen by Popa et al are consistent with the effects of cell-by-cell variations of growth rates, and mask diffusive gradients, and are unable to rule out a significant amount of periplasmic fN transport.
Effect on Heterocyst Differentiation of Nitrogen Fixation in Vegetative Cells of the Cyanobacterium Anabaena variabilisATCC 29413
Anabaena variabilis ATCC 29413 is unusual in that it has two Mo-dependent nitrogenases; one, called Nif1, functions in heterocysts, while the second, Nif2, functions under anoxic conditions in vegetative cells, suggesting that overall control of the process is not controlled by nitrogen insufficiency of individual cells.
PatS and Products of Nitrogen Fixation Control Heterocyst Pattern
It is concluded that patS and products of nitrogen fixation are the main signals determining the heterocyst patterns in cyanobacterium Anabaena sp.
Carbon and nitrogen fixation and metabolite exchange in and between individual cells of Anabaena oscillarioides
This innovative approach, combining stable isotope labeling and NanoSIMS elemental and isotopic imaging, allows characterization of cellular development (division, heterocyst differentiation), changes in individual cell composition and cellular roles in metabolite exchange.
Genetic and cytological evidence that heterocyst patterning is regulated by inhibitor gradients that promote activator decay
The results provide strong support for application of the activator-inhibitor model to heterocyst patterning and, more generally, the formation of periodic patterns in biological systems.
Early candidacy for differentiation into heterocysts in the filamentous cyanobacterium Anabaena sp. PCC 7120
Results suggest that the future heterocysts are loosely selected at early times after the start of nitrogen deprivation, before the commitment, which could be explained by different properties of the outer and inner cells of a quartet.
Under conditions of starvation for fixed nitrogen, cells of the filamentous cyanobacterium Anabaena variabilis Kütz, degrade much of their protein prior to heterocyst differentiation, and Methionine sulfoximine (MSX) in the presence of ammonia caused heterocysts to form.
Heterocyst development in Anabaena.
Heterocyst-Specific Expression of patB, a Gene Required for Nitrogen Fixation in Anabaena sp. Strain PCC 7120
expression of hetR and patS, two critical regulators of the heterocyst development cascade, are normal for patB mutants, indicating that patB acts downstream of them in the differentiation pathway.