Review Articles

Streptolysin S (SLS) is a cytolytic toxin and virulence factor produced by mostStreptococcus pyogenesstrains. This Review discusses advances in the study of SLS, the SLS-like peptide family, and its placement within the extended thiazole/oxazole-modified microcin (TOMM) family.

Bacterial pathogens secrete a range of effector proteins to target the signalling pathways that regulate host cell membranes. Here, Orth and colleagues describe the bacterial effectors that target phosphoinositide signalling, GTPase signalling and autophagy, and discuss how targeting these pathways can alter host membrane dynamics.

Leishmaniases, affecting over 150 million people worldwide, are caused by insect-borne protists of the genusLeishmania. Here, Kaye and Scott summarize the mechanisms involved in the establishment, survival and persistence of the different Leishmaniaspp. in their hosts, and highlight the pitfalls associated with a simplistic view of leishmanial pathogenesis.

Influenza A viruses continuously circulate and change in several animal hosts, and the emergence of novel strains that are capable of causing human epidemics or pandemics is a serious possibility. Here, Medina and García-Sastre discuss the importance of surveillance in identifying viruses with a potential risk to humans, and describe new developments in our understanding of viral host tropism and virulence.

Many bacterial pathogens produce protein toxins and effectors that target host regulatory GTPases such as those belonging to the RHO family, which control the actin cytoskeleton. In this Review, Aktories discusses the mechanisms used by these bacterial proteins to modulate the activity of host GTPases, with a focus on covalent modifications.

Biological nitrogen fixation is an important part of the marine nitrogen cycle, supporting carbon export and sequestration. In this Review, Sohm, Webb and Capone describe the nutrients that limit nitrogen fixation and the distribution of diazotrophic species in the world's oceans.

Enveloped viruses subvert a range of host proteins during their egress from the host cell. Here, Martin-Serrano and Neil describe our current understanding of the factors involved in retroviral budding from the cell surface and discuss how restriction factors, such as tetherin, can prevent viral release.

The dengue viruses that circulate among humans emerged from sylvatic progenitors that infected non-human primates. In this Review, Vasilakis and colleagues outline the ecology and evolution of sylvatic dengue viruses and their potential for further emergence in human transmission.

Internal hydrostatic pressure (turgor) is a major force driving the growth of hyphae in filamentous fungi. Here, Lew reviews the complex interplay of turgor, calcium gradients, transport of secretory vesicles by molecular motors, and mass flow of cytoplasm during fungal growth.

The archaeal cell surface is home to a range of lipids, proteins, polysaccharides and surface structures that are distinct from those observed at the bacterial cell surface. In this Review, Albers and Meyer discuss our current understanding of the composition of the archaeal cell envelope.

Fungi communicate with one another using chemical languages that consist of extracellular signals and sophisticated cellular responses. Glass and colleagues review the languages that are used by the largest phylum of fungi, the Ascomycota, during developmental processes such as germination, formation of mycelial networks through cell fusion, coordination of colony development, and both sexual and asexual reproduction.

Planctomycetes are bacteria that lack peptidoglycan in their cell walls and possess membrane-bound intracellular compartments, some of which may be analogous to the nucleus and the mitochondria of eukaryotes. Here, Fuerst and Sagulenko summarize recent progress in planctomycete cell biology and its implications for our understanding of the origin of eukaryotes.

Sulphate-reducing microorganisms have key roles in the biogeochemical cycling of sulphur, carbon, nitrogen and metals, as well as great biotechnological potential. Here, Zhou and colleagues describe recent applications of 'omics' tools to study the stress responses of these organisms, particularlyDesulfovibriospp., at the cell, population, community and ecosystem levels.

Manipulation of the host cell actin cytoskeleton is a common feature for many viruses. In this Review, Taylor, Koyuncu and Enquist describe how the interaction of viral proteins with the actin cytoskeleton alters the structure and function of this cytoskeleton, allowing viral infections to initiate, persist and spread.

Egress of herpesviruses requires that viral capsids containing the viral DNA travel from the nucleus to the cell surface, traversing nuclear and cytoplasmic membranes. Johnson and Baines describe how viral proteins remodel cellular membranes in order to escape host cells.

Entry of enveloped viruses into the host cell is an intricate process. Here, Connolly and colleagues describe the different proteins of herpes simplex viruses and Epstein–Barr virus that are involved in tethering the viruses to host cells and promoting fusion of the viruses with these host cells.

Termination is an important way of regulating transcription and requires stringent control. Here, Santangelo and Artsimovitch discuss the different mechanisms of antitermination in bacteria and phages.

Xanthomonasspp. cause disease in nearly 400 plant hosts, including many economically important crops. Dow and colleagues discuss the insights that functional and comparative genomic studies are providing into the adaptation of these bacteria to exploit an extraordinary diversity of plant hosts and different host tissues.

In this Review, Krulwich, Sachs and Padan describe how the evolution of diverse mechanisms for pH sensing and homeostasis has enabled bacteria to survive sudden changes in external pH and to grow in environments with external pH values that would otherwise be toxic.

The gut microbiota and the host immune system are in a careful balance. The Paneth cells in the endothelium of the small intestine produce a large array of antimicrobial proteins that help set this balance and protect the host from pathogens.