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In this Opinion article, Errington reviews the studies that describe the role of MreB in the determination and maintenance of rod cell shape in bacteria, and he presents a model to reconcile the conflicting data.

Bacterial cell division is orchestrated by the assembly of FtsZ into the Z ring, which functions as a scaffold for the assembly of the division machinery. Here, David Adams and Jeff Errington review the diverse repertoire of accessory proteins that interact with FtsZ during its assembly to render it both functional for division and responsive to cellular stresses.

Bacteria need to find the middle of the cell and prevent the formation of a division septum that bisects the chromosome. The nucleoid occlusion system, mediated by Noc inBacillus subtilis and SlmA in Escherichia coli, connects septum formation with chromosome segregation to optimize cell division.

Bacteria can form wall-deficient variants, or L-forms, that divide by a simple mechanism that does not require the FtsZ-based cell division machinery. Here, Wu et al. study L-forms in microfluidic systems to show the importance of geometric effects for cell growth, chromosome segregation and cell division.

Genetic and β-lactam antibiotic-driven cell wall deficiency leads to increased glycolytic flux and the generation of reactive oxygen species, which inhibits bacterial L-form growth.

Before it divides, a bacterium must move its replicated chromosomes away from the site of division, or risk having its DNA trapped in the membranes that separate the divided cells. How does it avoid this catastrophe?

The reservoir for recurrent urinary tract infection in humans is unclear. Here, Mickiewicz et al. detect cell-wall deficient (L-form) E. coli in fresh urine from patients, and show that the isolated bacteria readily switch between walled and L-form states.

Protein FtsZ plays key roles in cell division and is essential in most bacterial species; exceptions include streptomycetes, which grow from the cell tip and form branched hyphae. Here, Santos-Beneit et al. show that branching allows FtsZ-independent proliferation in Streptomyces venezuelae.

RodA is a peptidoglycan polymerase found in Bacillus subtilis. A bacterial extract may be able to target the peptidoglycan polymerase pathway and serve as an antibiotic.

Inhibition of bacterial cell wall synthesis by β-lactam antibiotics results in a loss of cell wall integrity, but cells die via a combination of downstream events involving metabolic perturbations and oxidative damage. Here, Kawai et al. identify key enzymatic steps that stimulate the generation of reactive oxygen species and highlight the role of iron homeostasis in the lethal effects mediated by oxidative damage.

Branched growth and division of bacteria with a cell wall but without a Z-ring may shed light on the evolution of bacterial morphogenesis.

L-form cells can derive from various bacterial species and do not possess a cell wall. It is shown that Bacillus subtilis can convert into L-form through a single point mutation, and that B. subtilus L-form cells are able to propagate independent of FtsZ, an essential component of the bacterial cell division machinery.

In this Review Egan, Errington and Vollmer discuss new insights into the molecular mechanisms of peptidoglycan synthesis, sacculus growth regulation and bacterial morphology, as well as how bacteria achieve robust cell wall growth under different conditions and stresses.

The application of modern fluorescence microscopic methods to bacteria has revolutionized our view of their subcellular organization. Many proteins are now known to be targeted with exquisite precision to specific locations in the cell, or to undergo rapid directed changes in localization. Structural and functional homologues of tubulin (FtsZ) and actin (MreB) are now indisputably present in bacteria, overturning the textbook view that the cytoskeleton is unique to eukaryotes. These advances are stimulating a radical rethink about how various fundamental processes are organised in bacteria.

Group BStreptococcus(GBS) is a pathogen of worldwide significance, and although prophylactic measures have reduced the number of infections, development of a vaccine remains an important goal. Here, the authors review the incidence of GBS and how new technologies are being applied in the search for a globally effective vaccine.

Recent studies have provided mechanistic insight into the cell cycle of coccoid bacteria. In this Review, Pinho, Kjos and Veening discuss our current understanding of the molecular mechanisms orchestrating peptidoglycan synthesis, cell division and chromosome segregation inStaphylococcus aureus and Streptococcus pneumoniae.

Classically associated with ageing and cancer, cellular senescence also seems to function in tissue remodelling during embryonic development and tissue repair, in which senescent cells are cleared before regeneration. Senescence is therapeutically relevant, as it can be either beneficial or detrimental in different diseases.