Progress

DNA replication is an essential process that requires very careful regulation. Tsutomu Katayama and colleagues describe the many ways in which the initiation of chromosomal DNA replication is controlled, with a particular focus on the regulation of DnaA.

Lipopolysaccharide (LPS) from Gram-negative bacteria is a potent activator of the innate immune response. Clare Bryant and colleagues discuss recent exciting data that have revealed the structural basis of the recognition of LPS by the Toll-like receptor 4–MD2 complex.

Bacteria need to adjust as they move between different environments. In this Progress article, Freitag, Port and Miner describe howListeria monocytogenesregulates the transition from saprophyte to human pathogen.

Tagging eukaryotic proteins with ubiquitin can target them for proteasomal degradation. However, despite the presence of proteasomes in several bacterial and all archaeal species, prokaryotic homologues of ubiquitin were presumed to be absent. In this Progress article, Heran Darwin describes the characterization of a prokaryotic ubiquitin-like protein (Pup) that is covalently attached to proteins, resulting in their proteasome-mediated degradation.

The use of microbial fuel cells to generate electrical current is increasingly being seen as a viable source of renewable energy production. In this Progress article, Bruce Logan highlights recent advances in our understanding of the mechanisms used by exoelectrogenic bacteria to generate electrical current and the important factors to consider in microbial fuel cell design.

CRISPR systems, which are composed of direct repeats that are separated by similarly sized non-repetitive spacers, confer resistance to phages in many bacteria and most archaea. This new antiviral tactic is thought to involve an RNA-interference-like mechanism, and is reviewed in this Progress article.

Shigellause a type III secretion system to deliver effector proteins into the host-cell cytoplasm, where they can usurp host-cell functions and signalling pathways. In this Progress article, Chihiro Sasakawa and colleagues highlight the most recent advances in our understanding of the exact functions of the manyShigellatype III-secreted effectors.

This Progress article looks at recent developments in our understanding of the role of the host factor Alix in both retroviral and cellular membrane budding and fission events.

In addition to their phagocytic activity, neutrophils can also kill microorganisms by the release of neutrophil extracellular traps or NETs — fibrous extracellular structures that are composed of chromatin with proteins from the neutrophilic granules attached. Brinkmann and Zychlinsky provide an overview of the structure, function and generation of NETs.

Pathogenic microorganisms have evolved numerous mechanisms that enable their exploitation of host cell function. This Progress article explores recent evidence suggesting how one group of diverse bacterial pathogens use a common strategy to manipulate the expression of the Kruppel-like factor (KLF) family of mammalian transcriptional regulators.