Unusual ultrastructural features in three strains of Cyanothece (cyanobacteria)

Porta, David; Rippka, Rosmarie; Hernández-Mariné, Mariona

doi:10.1007/s002039900126

Cited by 34 publications

(39 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several past studies have analyzed thoroughly the ultrastructure of some of the intracellularly calcifying strains studied here. For example, Porta et al (16) used a combination of confocal laser scanning microscopy and TEM to describe the ultrastructure of Cyanothece sp. PCC 7425; interestingly, they mentioned the unusually high content of light refractile inclusions when viewed by phasecontrast microscopy but did not conclude on their chemical composition.…”

Section: Resultsmentioning

confidence: 99%

“…However, many studies characterized the ultrastructure of cyanobacteria (16,17) and explored their impact on calcification (11,18,19), but none of them reported the presence of intracellular carbonates. Here, we investigated whether intracellular carbonate biomineralization is restricted to one particular species and/or specific environmental condition or whether it exists in other diverse cyanobacteria; this is essential to assess the evolution of intracellular carbonate Significance Cyanobacteria are known to promote the precipitation of Ca-carbonate minerals by the photosynthetic uptake of inorganic carbon.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

Benzerara

Skouri‐Panet

et al. 2014

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

198

211

View full text Add to dashboard Cite

Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Cacarbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra-and extracellular Ca-carbonate biomineralization by cyanobacteria.calcification | amorphous calcium carbonate | polyphosphate

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

Benzerara

Skouri‐Panet

et al. 2014

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

198

211

View full text Add to dashboard Cite

show abstract

“…The accumulation of membrane-rich structures as a result of overproduction of membrane proteins has been documented previously for both prokaryotic cells (3) and eukaryotic cells (2). There are also examples of membrane deposits that have been found naturally, such as the deposits found in certain cyanobacteria (23). Nevertheless, the observation of these extended structures provides an interesting view of the effects of overexpression of membrane proteins in a bacterial cell.…”

Section: Discussionmentioning

confidence: 99%

Three-Dimensional Electron Microscopic Imaging of Membrane Invaginations in Escherichia coli Overproducing the Chemotaxis Receptor Tsr

et al. 2004

View full text Add to dashboard Cite

Electron tomography is a powerful method for determining the three-dimensional structures of large macromolecular assemblies, such as cells, organelles, and multiprotein complexes, when crystallographic averaging methods are not applicable. Here we used electron tomographic imaging to determine the molecular architecture of Escherichia coli cells engineered to overproduce the bacterial chemotaxis receptor Tsr. Tomograms constructed from fixed, cryosectioned cells revealed that overproduction of Tsr led to formation of an extended internal membrane network composed of stacks and extended tubular structures. We present an interpretation of the tomogram in terms of the packing arrangement of Tsr using constraints derived from previous X-ray and electron-crystallographic studies of receptor clusters. Our results imply that the interaction between the cytoplasmic ends of Tsr is likely to stabilize the presence of the membrane networks in cells overproducing Tsr. We propose that membrane invaginations that are potentially capable of supporting axial interactions between receptor clusters in apposing membranes could also be present in wild-type E. coli and that such receptor aggregates could play an important role in signal transduction during bacterial chemotaxis.Over the last three decades, methods for three-dimensional reconstruction of objects (5) imaged with an electron microscope have been used to determine the structures of a variety of biological assemblies by two types of approaches. One approach, which has been used extensively in analyses of large macromolecular assemblies, involves three-dimensional reconstruction of a structure by averaging images recorded from several identical copies oriented randomly relative to the electron beam (11, 31). The other approach, which has been used for reconstruction of objects that cannot be easily averaged, such as whole cells, involves tomographic reconstruction by combining projection images of an object recorded with an electron microscope over a range of tilt angles (4). Electron tomography is therefore a potentially powerful tool for threedimensional imaging of the spatial arrangement of proteins that make up complex and dynamic assemblies, such as those involved in bacterial chemotaxis.At least 12 proteins act in concert to convert the signal of ligand binding at the periplasmic end of a chemotaxis receptor into rotation of the flagellar motor (6, 27). The principal protein components at the input end include one of the chemotaxis receptors (Tsr, Tar, Trg, Tap, or Aer), and the cytoplasmic signaling proteins CheA and CheW, which are thought to form a noncovalent complex with the chemotaxis receptors. Knowledge of the structure and spatial arrangement of the chemotaxis receptors is therefore fundamental to understanding the structural biology of signaling. X-ray crystallographic studies of the periplasmic fragments of the aspartate receptor fragments have revealed the dimeric organization of the ligand binding domain, in which the ligand binding pocket is located at...

show abstract

“…Briefly, the M. tuberculosis H37Ra cells were grown to an optical density at 600 nm (OD 600 ) of 0.6, corresponding to the mid-log phase (day 5) of growth, and cells were suspended in lysis buffer and boiled for 45 min. The total cell lysate was subjected to SDS-PAGE, along with different amounts of purified Rv3852 (40,30,20, and 15 ng), and detected by immunoblotting with anti-Rv3852 antibody. Quantitation of band intensities was carried out by scanning the bands and analyzing the image with Image Gauge V2.54 software.…”

Section: Methodsmentioning

confidence: 99%

Regulation of Lipid Biosynthesis, Sliding Motility, and Biofilm Formation by a Membrane-Anchored Nucleoid-Associated Protein of Mycobacterium tuberculosis

2013

View full text Add to dashboard Cite

bBacteria use a number of small basic proteins for organization and compaction of their genomes. By their interaction with DNA, these nucleoid-associated proteins (NAPs) also influence gene expression. Rv3852, a NAP of Mycobacterium tuberculosis, is conserved among the pathogenic and slow-growing species of mycobacteria. Here, we show that the protein predominantly localizes in the cell membrane and that the carboxy-terminal region with the propensity to form a transmembrane helix is necessary for its membrane localization. The protein is involved in genome organization, and its ectopic expression in Mycobacterium smegmatis resulted in altered nucleoid morphology, defects in biofilm formation, sliding motility, and change in apolar lipid profile. We demonstrate its crucial role in regulating the expression of KasA, KasB, and GroEL1 proteins, which are in turn involved in controlling the surface phenotypes in mycobacteria.

show abstract

Unusual ultrastructural features in three strains of Cyanothece (cyanobacteria)

Cited by 34 publications

References 28 publications

Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

Three-Dimensional Electron Microscopic Imaging of Membrane Invaginations in Escherichia coli Overproducing the Chemotaxis Receptor Tsr

Regulation of Lipid Biosynthesis, Sliding Motility, and Biofilm Formation by a Membrane-Anchored Nucleoid-Associated Protein of Mycobacterium tuberculosis

Contact Info

Product

Resources

About