Spatio-temporal control of asymmetric septum positioning during sporulation in Bacillus subtilis.

During sporulation, Bacillus subtilis forms an asymmetric septum, dividing the cell into two compartments, a mother cell and a forespore. The site of asymmetric septation is linked to the membrane where FtsZ and SpoIIE initiate the formation of the Z-ring and the E-ring, respectively. These rings then serve as a scaffold for the other cell division and peptidoglycan synthesizing proteins needed to build the septum.

Author Correction: Bacterial nanotubes as a manifestation of cell death.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Bacterial nanotubes as a manifestation of cell death.

Bacterial nanotubes are membranous structures that have been reported to function as conduits between cells to exchange DNA, proteins, and nutrients. Here, we investigate the morphology and formation of bacterial nanotubes using Bacillus subtilis. We show that nanotube formation is associated with stress conditions, and is highly sensitive to the cells' genetic background, growth phase, and sample preparation methods.

The positioning of the asymmetric septum during sporulation in Bacillus subtilis.

Probably one of the most controversial questions about the cell division of Bacillus subtilis, a rod-shaped bacterium, concerns the mechanism that ensures correct division septum placement-at mid-cell during vegetative growth but closer to one end during sporulation. In general, bacteria multiply by binary fission, in which the division septum forms almost exactly at the cell centre. How the division machinery achieves such accuracy is a question of continuing interest.

Interaction of the Morphogenic Protein RodZ with the Min System.

Vegetative cell division in takes place precisely at the middle of the cell to ensure that two viable daughter cells are formed. The first event in cell division is the positioning of the FtsZ Z-ring at the correct site. This is controlled by the coordinated action of both negative and positive regulators.

Control of Bacillus subtilis cell shape by RodZ.

The bacterial cell wall ensures the structural integrity of the cell and is the main determinant of cell shape. In Bacillus subtilis, three cytoskeletal proteins, MreB, MreBH and Mbl, are thought to play a crucial role in maintaining the rod cell shape. These proteins are thought to be linked with the transmembrane proteins MreC, MreD and RodA, the peptidoglycan hydrolases, and the penicillin-binding proteins that are essential for peptidoglycan elongation.

The role of lipid domains in bacterial cell processes.

Membranes are vital structures for cellular life forms. As thin, hydrophobic films, they provide a physical barrier separating the aqueous cytoplasm from the outside world or from the interiors of other cellular compartments. They maintain a selective permeability for the import and export of water-soluble compounds, enabling the living cell to maintain a stable chemical environment for biological processes.

An oscillating Min system in Bacillus subtilis influences asymmetrical septation during sporulation.

The Min system plays an important role in ensuring that cell division occurs at mid-cell in rod-shaped bacteria. In Escherichia coli, pole-to-pole oscillation of the Min proteins specifically inhibits polar septation. This system also prevents polar division in Bacillus subtilis during vegetative growth; however, the Min proteins do not oscillate in this organism.

Changes of lipid domains in Bacillus subtilis cells with disrupted cell wall peptidoglycan.

The cell wall is responsible for cell integrity and the maintenance of cell shape in bacteria. The Gram-positive bacterial cell wall consists of a thick peptidoglycan layer located on the outside of the cytoplasmic membrane. Bacterial cell membranes, like eukaryotic cell membranes, are known to contain domains of specific lipid and protein composition.

Expression and localization of SpoIISA toxin during the life cycle of Bacillus subtilis.

The previously identified spoIIS locus encodes a toxin-antitoxin system in Bacillus subtilis. It comprises two genes, spoIISA encoding a toxin and spoIISB encoding an antitoxin, which lies adjacent to each other on the chromosome. Each of the spoIIS coding sequences is preceded by a promoter region and the two genes together constitute an operon.

Lipid domains in Bacillus subtilis anucleate cells.

Bacterial membranes are known to form domains with specific lipid compositions and functions. Recently, using membrane binding fluorescent dyes, lipid spiral structures extending along the long axis of the cell were detected. These spirals were absent when the synthesis of phosphatidylglycerol and cardiolipin was disrupted, suggesting that the spirals are enriched in anionic phospholipids.

Comparison of different Bacillus subtilis expression systems.

Bacillus subtilis is considered to have great potential as a host for the production and secretion of recombinant proteins. Many different expression systems have been developed for B. subtilis.

Expression of Escherichia coli Min system in Bacillus subtilis and its effect on cell division.

In both rod-shaped Bacillus subtilis and Escherichia coli cells, Min proteins are involved in the regulation of division septa formation. In E. coli, dynamic oscillation of MinCD inhibitory complex and MinE, a topological specificity protein, prevents improper polar septation.

Lipid spirals in Bacillus subtilis and their role in cell division.

The fluid mosaic model of membrane structure has been revised in recent years as it has become evident that domains of different lipid composition are present in eukaryotic and prokaryotic cells. Using membrane binding fluorescent dyes, we demonstrate the presence of lipid spirals extending along the long axis of cells of the rod-shaped bacterium Bacillus subtilis. These spiral structures are absent from cells in which the synthesis of phosphatidylglycerol is disrupted, suggesting an enrichment in anionic phospholipids.

Expression of functional Bacillus SpoIISAB toxin-antitoxin modules in Escherichia coli.

SpoIISA and SpoIISB proteins from Bacillus subtilis belong to a recently described bacterial programmed-cell death system. The current work demonstrates that the toxin-antitoxin module is also functional in Escherichia coli cells, where the expression of SpoIISA toxin leads to transient growth arrest coupled with cell lysis, and SpoIISA-induced death can be prevented by coexpression of its cognate antitoxin, SpoIISB. Escherichia coli cells appear to be able to escape the SpoIISA killing by activation of a specific, as yet unidentified protease that cleaves out the cytosolic part of the protein.

The response regulator Spo0A from Bacillus subtilis is efficiently phosphorylated in Escherichia coli.

The response regulator proteins of two-component systems mediate many adaptations of bacteria to their ever-changing environment. Most response regulators are transcription factors that alter the level of transcription of specific sets of genes. Activation of response regulators requires their phosphorylation on a conserved aspartate residue by a cognate sensor kinase.

Bacillus subtilis division protein DivIVA - screen for stable oligomer state conditions.

The cell division protein DivIVA is predicted to be a coiled-coil, tropomyosin-like protein, that self-associates both in vivo and in vitro into oligomers of up to 10-12 monomers. A simple and quick screen for conditions supporting the stable oligomer structure has been developed revealing that DivIVA forms a homogeneous oligomer in the presence of PEGs (PEG 4 K or PEG 8K and PEG 1K).