Review Articles in 2009

Type IV secretion systems (T4SSs) are found in both Gram-negative and Gram-positive bacteria and generally comprise 12 protein components that are organized into ATP-powered, double-membrane-spanning complexes. Here, Fronzes, Christie and Waksman review the structural data of many T4SS components and propose a model for the assembly of a functional type IV secretion apparatus.

Production of biofuels is becoming increasingly important. In this Review, Alper and Stephanopoulos describe the advantages and disadvantages of the use of native strains and engineered model microorganisms for the production of biofuels.

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.

Epidemics caused by antibiotic-resistant strains ofStaphylococcus aureus often occur in waves. Here, Henry Chambers and Frank DeLeo review the molecular epidemiology of the epidemic waves of penicillin- and methicillin-resistant strains of S. aureus that have occurred since 1940, with a focus on community-associated methicillin-resistant S. aureus.

Pseudomonas aeruginosauses a type III secretion system to proliferate within the host. Here, Alan Hauser describes the regulation of the formation of this secretion system, the components that allow the transfer of effectors into the host and the activity of these effectors.

Cryo-electron tomography is beginning to open a window on the bacterial cell, enabling internal structural organization to be imaged at high resolutions. In this Review article, Milne and Subramaniam assess the applicability and limitations of cryo-electron tomography for bacterial cell imaging and highlight the recent advances made in this exciting field.

Adaptor proteins for the Hsp100/Clp and AAA+ proteins play an important part in the regulated degradation of a large number of bacterial processes. Kirstein and colleagues describe how these adaptor proteins interact with their respective proteases to regulate proteolysis.

Anaerobic methane formation and oxidation are important processes in the global carbon cycle that are mediated by syntrophic communities of bacteria and archaea. Here, Fons Stams and Caroline Plugge review the interspecies electron transfer that is the key to growth in syntrophic communities.

Gene duplication and amplification can enable bacteria not only to develop antibiotic resistance, but also to overcome the fitness costs that are often associated with resistance. In this Review, Sandegren and Andersson highlight the mechanisms underlying gene duplication and discuss the role of increasing gene copy number in adaptive bacterial evolution.

The commensal bacteriumStaphylococcus epidermidis is a colonizer of the human skin. Despite lacking recognized virulence factors, S. epidermidiscan cause infection, often on the surface of indwelling medical devices. In this Review, Michael Otto highlights how normally benign bacterial factors take on more virulent roles during host infection with this 'accidental' pathogen.

The identification of post-translational histone modifications and chromatin-modifying enzymes in eukaryotic parasites has widened the field of research into epigenetic regulation. Figueiredo, Cross and Janzen compare the role of epigenetics inTrypanosoma bruceiand humans and discuss how studies in such parasites might yield useful information about the evolution of epigenetic processes.

Bacteria from the genusStenotrophomonas are found in a wide range of different environments. Here, Ryan et al. compare the recently sequenced genomes of two different Stenotrophomonasspecies to highlight the possible genetic basis of adaptation to these different niches.

Since 2001, the prevalence and severity ofClostridium difficile infection have increased substantially, and C. difficile is now considered to be one of the most important causes of health care-associated infections. Here, Rupnik, Wilcox and Gerding discuss the recent epidemiological changes in C. difficile infection and our current knowledge of C. difficilevirulence factors.

To evade immune responses in mammalian hosts, many pathogens use complex genetic systems to vary the surface antigens that are recognized by host defences. In this Review, Kirk Deitsch and colleagues highlight how bacterial, protozoan and fungal pathogens from distinct evolutionary lineages have evolved surprisingly similar mechanisms for antigenic variation.

Galectins are important for recognition of carbohydrate ligands during embryogenesis, development and immune regulation. In addition, recent work has shown that galectins also function as receptors for glycans expressed on the surface of potentially pathogenic microorganisms. In this Review, Gerardo Vasta discusses the roles of galectins in host immunity and how pathogens have evolved to evade or subvert galectin-mediated immune responses.

Coronaviruses gained prominence during the SARS outbreaks of 2002–2003, but there are many different coronaviruses that infect humans and animals. Perlman and Netland describe the biology of the coronaviruses, including their replication, host immune response and interspecies transmission.

Cleavage of membrane proteins by intramembrane proteases can release effector domains that carry out a range of cellular functions. In higher eukaryotes, the functions of such proteases are well characterized. However, the importance of such proteases in unicellular organisms is only recently being appreciated. In this article, Sin Urban reviews the recent advances in our understanding of how intramembrane proteases play pivotal parts in a range of pathogenic microorganisms.

The host cell and intracellular pathogens are in a continuous struggle. Flannagan, Cosío and Grinstein describe the pathway by which the bacteria are taken up, the antimicrobial mechanisms of the host cell and the different ways bacteria evade these mechanisms.

Movies, made possible by the combination of time-lapse microscopy, quantitative image analysis and fluorescent protein reporters, are allowing us to directly observe various cellular components over time in individual cells. As such, movies are providing powerful insights into the behaviour of genetic circuit behaviours in diverse microbial systems.

For diseases that are both rare and lethal, it is difficult to test vaccines. Sullivan and colleagues describe the use of immune correlates and the animal rule for the licensing of Ebola vaccines.