Heterocyst differentiation and pattern formation in cyanobacteria: a chorus of signals

Zhang, Cheng‐Cai; Laurent, Sophie; Sakr, Samer; Peng, Ling; Bédu, Sylvie

doi:10.1111/j.1365-2958.2005.04979.x

Cited by 404 publications

(205 citation statements)

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“…Phycobiliproteins are also known to have a role in cyanobacterial nitrogen storage (Allen et al, 1984;Kromkamp, 1987). This increase in fluorescence might indicate that the heterocysts are using PE for an intracellular nitrogen storage facility (Figures 3d and i) (Wyman et al, 1985;Janson et al, 1995b;Wingard et al, 2002;Zhang et al, 2006). Nitrogen storage as PE, combined with the close physical proximity between cyanobiont and host, may imply that nitrogen is rapidly assimilated once fixed by the R. intracellularis.…”

Section: Identification and Characterization Of The Diatomdiazotroph mentioning

confidence: 99%

“…The heterocysts were visible only when the organisms were excited with the PE or PC filter sets. This might be due to low concentrations of Chl a in these specialized nitrogen-fixing cells where no PSII activity occurs (Zhang et al, 2006). The diatom host can acquire their cyanobiont via two major pathways: either directly from the aquatic environment, or, through the parental cells following cell division (Villareal, 1989;Rai et al, 2000).…”

Section: Identification and Characterization Of The Diatomdiazotroph mentioning

confidence: 99%

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Seasonal dynamics of the endosymbiotic, nitrogen-fixing cyanobacterium Richelia intracellularis in the eastern Mediterranean Sea

et al. 2008

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Biological nitrogen fixation has been suggested as an important source of nitrogen for the ultraoligotrophic waters of the Levantine Basin of the Mediterranean Sea. In this study, we identify and characterize the spatial and temporal distribution of the N-fixing (diazotrophic) cyanobacterium Richelia intracellularis. R. intracellularis is usually found as an endosymbiont within diatoms such as Rhizosolenia spp and Hemiaulus spp. and is an important diazotroph in marine tropical oceans. In this study, two stations off the Mediterranean coast of Israel were sampled monthly during 2005-2007. R. intracellularis was identified by microscopy and by reverse transcribed-PCR which confirmed a 98.8% identity with known nifH sequences of R. intracellularis from around the world. The diatom-diazotroph associations were found throughout the year peaking during autumn (October-November) at both stations. Abundance of R. intracellularis ranged from 10 to 55 heterocysts l À1 and correlated positively with the dissolved Si(OH) 4 /(NO 3 þ NO 2 ) ratio in surface waters. Although the rates of nitrogen fixation were very low, averaging B1.1 nmol N l À1 day À1 for the R. intracellularis size fraction (410 lm) from surface waters, they correlated positively with heterocyst counts during thermal stratification. The lack of large-scale diatom-diazotroph blooms and the low rates of nitrogen fixation by these diazotrophs may result from the P-starved conditions affecting the Levantine basin.

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Section: Identification and Characterization Of The Diatomdiazotroph mentioning

confidence: 99%

Section: Identification and Characterization Of The Diatomdiazotroph mentioning

confidence: 99%

Seasonal dynamics of the endosymbiotic, nitrogen-fixing cyanobacterium Richelia intracellularis in the eastern Mediterranean Sea

et al. 2008

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“…The activator-inhibitor system governing this patterning consists of a self-enhancing activator protein, HetR (8,9), and its antagonist, proteins containing a pentapeptide, PatS-5 (RGSGR) (10,11). These two primary positive and negative acting regulatory elements are modulated by several other elements (5,6,12,13). Deletion of patS (10) and overexpression of hetR (9) each results in clusters of two or more heterocysts [multiple contiguous heterocysts (Mch)] forming at nonrandomly spaced sites in the filaments.…”

mentioning

confidence: 99%

Biased inheritance of the protein PatN frees vegetative cells to initiate patterned heterocyst differentiation

Risser

Wong

Meeks

2012

Proc. Natl. Acad. Sci. U.S.A.

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Heterocysts, cells specialized for nitrogen fixation in certain filamentous cyanobacteria, appear singly in a nonrandom spacing pattern along the chain of vegetative cells. A two-stage, biased initiation and competitive resolution model has been proposed to explain the establishment of this spacing pattern. There is substantial evidence that competitive resolution of a subset of cells initiating differentiation occurs by interactions between a selfenhancing activator protein, HetR, and a diffusible pentapeptide inhibitor PatS-5 (RGSGR). Results presented here show that the absence of a unique membrane protein, PatN, in Nostoc punctiforme strain ATCC 29133 leads to a threefold increase in heterocyst frequency and a fourfold decrease in the vegetative cell interval between heterocysts. A PatN-GFP translational fusion shows a pattern of biased inheritance in daughter vegetative cells of ammonium-grown cultures. Inactivation of another heterocyst patterning gene, patA, is epistatic to inactivation of patN, and transcription of patA increases in a patN-deletion strain, implying that patN may function by modulating levels of patA. The presence of PatN is hypothesized to decrease the competency of a vegetative cell to initiate heterocyst differentiation, and the cellular concentration of PatN is dependent on cell division that results in cells transiently depleted of PatN. We suggest that biased inheritance of cell-fate determinants is a phylogenetic domain-spanning paradigm in the development of biological patterns.activator-inhibitor | pattern differentiation T wo broad strategies used in the development of biological patterns are activator-inhibitor systems, a refinement of Turing-type reaction-diffusion systems (1, 2), and differential inheritance of cell fate determinants (3, 4). These strategies have been analyzed in multicellular eukaryotes ranging in developmental complexity from hydra to vertebrates (1, 4). Some filamentous cyanobacteria show spaced patterns of differentiated cells, such as nitrogen-fixing heterocysts and spore-like akinetes, thereby representing the simplest and oldest evolutionary model for study of the development of biological patterns and multicellular interactions. There is strong experimental evidence that an activatorinhibitor system regulates heterocyst patterning in filamentous cyanobacteria (5-7). We report here the characteristics of a gene (patN) that is required for normal heterocyst patterning, and the phenotype and protein localization of which is consistent with a role in the biased initiation of heterocyst differentiation via biased inheritance.Heterocysts terminally differentiate from vegetative cells in response to limitation of combined nitrogen. The heterocysts appear in a nonrandom spacing of approximately 1 heterocyst to every 10-15 vegetative cells. The activator-inhibitor system governing this patterning consists of a self-enhancing activator protein, HetR (8, 9), and its antagonist, proteins containing a pentapeptide, PatS-5 (RGSGR) (10, 11). These two primary positi...

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“…Some cyanobacteria can simultaneously carry out oxygenic photosynthesis and nitrogen fixation, which are two biochemically incompatible processes. When combined nitrogen is scarce, some photosynthetic vegetative cells differentiate into specialized nitrogen-fixing cells called heterocysts (5)(6)(7)(8)(9). The signaling network during heterocyst differentiation is highly complex and recalls that of eukaryotic cells.…”

mentioning

confidence: 99%

Structures of Anabaena Calcium-binding Protein CcbP

Hu¹,

Zhang²,

Shi³

et al. 2011

Journal of Biological Chemistry

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Heterocyst differentiation and pattern formation in cyanobacteria: a chorus of signals

Cited by 404 publications

References 50 publications

Seasonal dynamics of the endosymbiotic, nitrogen-fixing cyanobacterium Richelia intracellularis in the eastern Mediterranean Sea

Seasonal dynamics of the endosymbiotic, nitrogen-fixing cyanobacterium Richelia intracellularis in the eastern Mediterranean Sea

Biased inheritance of the protein PatN frees vegetative cells to initiate patterned heterocyst differentiation

Structures of Anabaena Calcium-binding Protein CcbP

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