Specific Adhesion of Bacteria to Heterocysts of
            <i>Anabaena</i>
            spp. and Its Ecological Significance

Lupton, F. Stephen; Marshall, K. C.

doi:10.1128/aem.42.6.1085-1092.1981

Cited by 37 publications

(11 citation statements)

References 17 publications

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“…). These highly specific associations can be beneficial to the cyanobacterium by improving nitrogen fixation rates (Lupton and Marshall , Paerl and Gallucci ). Bacterial communities associated with planktonic bloom‐forming diazotrophs have been investigated (e.g., Eiler et al.…”

mentioning

confidence: 99%

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

Secker

Chua

Laurie

et al. 2016

Journal of Phycology

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New Zealand ephemeral wetlands are ecologically important, containing up to 12% of threatened native plant species and frequently exhibiting conspicuous cyanobacterial growth. In such environments, cyanobacteria and associated heterotrophs can influence primary production and nutrient cycling. Wetland communities, including bacteria, can be altered by increased nitrate and phosphate due to agricultural practices. We have characterized cyanobacteria from the Wairepo Kettleholes Conservation Area and their associated bacteria. Use of 16S rRNA amplicon sequencing identified several operational taxonomic units (OTUs) representing filamentous heterocystous and non-heterocystous cyanobacterial taxa. One Nostoc OTU that formed macroscopic colonies dominated the cyanobacterial community. A diverse bacterial community was associated with the Nostoc colonies, including a core microbiome of 39 OTUs. Identity of the core microbiome associated with macroscopic Nostoc colonies was not changed by the addition of nutrients. One OTU was highly represented in all Nostoc colonies (27.6%-42.6% of reads) and phylogenetic analyses identified this OTU as belonging to the genus Sphingomonas. Scanning electron microscopy showed the absence of heterotrophic bacteria within the Nostoc colony but revealed a diverse community associated with the colonies on the external surface.

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mentioning

confidence: 99%

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

Secker

Chua

Laurie

et al. 2016

Journal of Phycology

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“…The difficulty of reaching axenicity results from bacterial communities living in close relationship with 3 Cyanobacteria in nature. This microbiome has been described both from environmental samples (15)(16)(17)(18)(19) and non-axenic cultures (20)(21)(22). Moreover, Bacteria/Cyanobacteria associations appear to be stable in culture, as no significant differences could be found between bacterial communities accompanying Cyanobacteria in fresh samples and collection cultures (21).…”

Section: Introductionmentioning

confidence: 94%

Metagenomic assembly of new (sub)arctic Cyanobacteria and their associated microbiome from non-axenic cultures

Cornet

Bertrand

Hanikenne

et al. 2018

Preprint

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Cyanobacteria form one of the most diversified phylum of Bacteria. They are important ecologically as primary producers, for Earth evolution and biotechnological applications. Yet, Cyanobacteria are notably difficult to purify and grow axenically, 1 and most strains in culture collections contain heterotrophic bacteria that were likely associated to Cyanobacteria in the environment. Obtaining cyanobacterial DNA without contaminant sequences is thus a challenging and time-consuming task.Here, we deploy a metagenomic pipeline that enables the easy recovery of highquality genomes from non-axenic cultures. We tested this pipeline on 17 cyanobacterial cultures from the BCCM/ULC public collection and generated novel genome sequences for 15 arctic or subarctic strains, of which 14 early-branching organisms that will be useful for cyanobacterial phylogenomics. In parallel, we managed to assemble 31 co-cultivated bacteria from the same cultures and showed that they mostly belong to Bacteroidetes and Proteobacteria, some of them being very closely related in spite of geographically distant sampling sites. ImportanceComplete genomes of cold-adapted Cyanobacteria are underrepresented in databases, due to the difficulty to grow them axenically. In this work, we report the genome sequencing of 12 (sub)arctic and 3 temperate Cyanobacteria, along with 21 Proteobacteria and 5 Bacteroidetes recovered from their microbiome. Following the use of a state-of-the-art metagenomic pipeline, 12 of our new cyanobacterial genome assemblies are of high-quality, which indicates that even non-axenic cultures can yield complete genomes suitable for phylogenomics and comparative genomics. From a methodological point of view, we investigate the fate of SSU rRNA (16S) genes during metagenomic binning and observe that multi-copy rRNA operons are lost because of higher sequencing coverage and divergent tetranucleotide frequencies. Moreover, we devised a measure of genomic identity to compare metagenomic bins of different completeness, which allowed us to show that 2 Cyanobacteria-associated bacteria can be highly related in spite of considerable distance between collection points.

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“…Thus, aggregation has been proposed to confer a physiological fitness, improving nitrogen fixation rates (reviewed in Paerl, 2012). Additionally, nitrogen fixation in heterocyst-forming cyanobacteria has also been shown to benefit from the presence of heterotrophic bacteria that specifically associate to the heterocysts (Lupton and Marshall, 1981;Paerl and Gallucci, 1985;Paerl and Pinckney, 1996). In such associations, it is proposed that heterotrophic bacteria consume oxygen close to the heterocysts, reducing the oxygen pressure around those cells, and so cyanobacteria present higher nitrogenase activity rates (Paerl and Gallucci, 1985;Paerl and Pinckney, 1996).…”

Section: Hesf Functionmentioning

confidence: 99%

HesF, an exoprotein required for filament adhesion and aggregation in Anabaena sp. PCC 7120

Oliveira

Pinto

Pacheco

et al. 2014

Environmental Microbiology

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SummaryHere, we report on the identification and characterization of a protein (Alr0267) named HesF, found in the extracellular milieu of Anabaena sp. PCC 7120 grown diazotrophically. hesF was found to be highly upregulated upon transition from non-nitrogen-fixing to nitrogen-fixing conditions, and the highest transcript levels were detected towards the end of the heterocyst differentiation process. The hesF promoter drives transcription of the gene in heterocysts only, and both NtcA and HetR are essential for the gene's in vivo activation. An examination of HesF's translocation showed that the secretion system is neither heterocyst-specific nor dependent on nitrogen-fixing conditions. Furthermore, HesF was found to be a type I secretion system substrate, since an HgdD mutant failed to secrete HesF. Several analyses revealed that a HesF minus mutant strain lacks the heterocyst-specific polysaccharide fibrous layer, accumulates high amounts of polysaccharides in the medium and that HesF is essential for the typical aggregation phenotype in diazotrophic conditions. Thus, we propose that HesF is a carbohydratebinding exoprotein that plays a role in maintaining the heterocyst cell wall structure. A combination of and possibly interaction between HesF and heterocystspecific polysaccharides seems to be responsible for filament adhesion and culture aggregation in heterocyst-forming cyanobacteria.

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Specific Adhesion of Bacteria to Heterocysts of Anabaena spp. and Its Ecological Significance

Cited by 37 publications

References 17 publications

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

Characterization of the cyanobacteria and associated bacterial community from an ephemeral wetland in New Zealand

Metagenomic assembly of new (sub)arctic Cyanobacteria and their associated microbiome from non-axenic cultures

HesF, an exoprotein required for filament adhesion and aggregation in Anabaena sp. PCC 7120

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