Review Articles in 2008

Streptococcus pneumoniaeis one of the most common bacterial respiratory pathogens. In this article, the authors review the impressive armamentarium of virulence factors the pneumococcus uses to colonize the upper and lower respiratory tracts of the host and cause disease.

Carbohydrate-based polymers are constituents of the cell envelopes of many Gram-positive bacteria. These cell-wall glycopolymers often have highly variable structures and, although their functions are not completely known, recent research has begun to reveal that they have crucial roles in both protecting and maintaining the bacterial cell envelope and in bacteria–host interactions.

Interactions between insects and microorganisms are important in insect disease, dissemination of pathogens to animals and plants, and as models for host–pathogen interactions. Here, the interactions between bacteria and insects, and the strategies that both use to influence these interactions, are reviewed.

The successful replication of mammalian DNA viruses requires that they gain control of key cellular signalling pathways, including the phosphatidylinositol 3′-kinase–Akt–mammalian target of rapamycin (PI3K–Akt–mTOR) pathway. This Review discusses the range of mechanisms that mammalian DNA viruses use to activate this pathway, as well as the multiple mechanisms these viruses have evolved to circumvent inhibitory stress signalling.

Knipe and Cliffe review the mechanisms that underlie the switch from a lytic to a latent infection in the widespread pathogen herpes simplex virus (HSV). They propose a new model in which an epigenetic switch determines whether a lytic or a latent infection occurs and discuss viral functions that might regulate chromatin assembly on the HSV genome and effect this epigenetic switch.

Stewart and Franklin discuss the processes that generate chemical gradients in biofilms, the genetic and physiological responses of the bacteria as they adapt to these gradients and the techniques that can be used to visualize and measure microscale physiological heterogeneities of bacteria in biofilms.

The insertion of proteins into the bacterial cytoplasmic membrane is a complex and dynamic process. Sophisticated translocases are responsible for decoding the topogenic sequences within membrane proteins that direct membrane protein insertion and orientation. Here, Xie and Dalbey highlight what is known about the role of the Sec and YidC translocases in the folding and insertion of bacterial membrane proteins.

Leah Cowen reviews the mechanisms that potentiate the evolution of fungal drug resistance, with an emphasis on the central role of the molecular chaperone heat shock protein 90 (Hsp90) in altering the relationship between genotype and phenotype in an environmentally contingent manner, which thereby 'sculpts' the course of evolution.

Bacteria can precisely adjust their membrane lipid compositions to control the biophysical properties of their membranes, which allows them to thrive in various physical environments. Here, Charles Rock and Yong-Mei Zhang review the biochemical processes that are responsible for bacterial membrane lipid homeostasis.

The complement system is an essential and efficient component of the immune system's antimicrobial machinery, but many pathogens have developed parallel routes of escape. Understanding complement processes and interactions on a molecular level is essential for the development of novel therapies, and this Review provides a comprehensive overview and update of recent developments in this field.

Mutually beneficial relationships between prokaryotes and eukaryotes are possible because of the ability of microorganisms and their hosts to communicate with each other. In this Review, David Hughes and Vanessa Sperandio discuss how inter-kingdom communication can be 'hijacked' by bacterial pathogens, and how hosts can fight back.

Dietary plant polysaccharides are a major energy source for the anaerobic microbiota that inhabit the mammalian large intestine and rumen. Flint and colleagues discuss polysaccharide utilization by gut anaerobes, focusing on two examples, the use of insoluble structural polysaccharides byRuminococcus flavefaciens and the use of starch by Bacteroides thetaiotaomicron.

The exit of intracellular bacteria from host cells is a crucial stage in microbial pathogenesis that is driven by an evolutionary requirement for efficient dissemination to neighbouring cells and transmission to new hosts. In this comprehensive Review, the authors discuss the diverse repertoire of strategies that is used by intracellular pathogens to escape their host cells.

Most viral vaccines protect against disease by generating neutralizing antibodies. This Review examines the problem of eliciting broad HIV-1 neutralization through vaccination by drawing parallels with the successful subunit influenza virus vaccine and with efforts to develop a pandemic influenza vaccine.

Why do we seem to be losing the fight against tuberculosis? In this Review, James Sacchettini, Eric Rubin and Joel Freundlich review the recent and ongoing efforts to produce new antitubercular drugs and the properties of current investigational agents.

Targeting bacterial virulence is an alternative approach to antimicrobial therapy. This Review considers recent efforts towards antivirulence-based drug discovery in the framework of marketable drugs, and discusses what challenges remain and the factors that are crucial to developing the antivirulence therapeutic approach.

Salmonellae cause systemic diseases by invading and replicating inside epithelial cells and macrophages. Two functionally distinct type III secretion systems that are encoded onSalmonella pathogenicity islands 1 and 2 transfer Salmonellaspp. effector proteins into host cells. The dynamic molecular interplay between these bacterial effectors and host responses is discussed in this Review.

Recognition of fungi by the innate immune system depends on 'tasting' several pathogen-associated molecular patterns in the fungal cell wall. In this Review, the authors pull together the availablein vitro and in vivo data to propose an integrated model for Candida albicansrecognition by the innate immune system.

Bacteria have evolved several different mechanisms to target protein complexes, membrane vesicles and DNA to specific positions within the cell. Here, Thanbichler and Shapiro highlight key mechanisms of cellular organization in bacteria, with an emphasis on the role of polymeric protein assemblies in the directed movement and positioning of macromolecular complexes.

John C. Boothroyd and Jean-Francois Dubremetz review the roles of the apical rhoptry organelles in cell invasion by Apicomplexan parasites such asToxoplasma gondii and Plasmodiumspp. They propose a model in which an expansion of host range might have been the selective pressure for rhoptry-protein evolution.