Review Articles in 2014

Botulinum neurotoxins, which are the most powerful known toxins, are produced by toxigenic clostridia and cause persistent paralysis of peripheral nerve terminals by blocking neurotransmitter release. In this Review, Montecucco and colleagues discuss recent structural and molecular insights into the mechanisms of toxin entry into nerve terminals, membrane translocation and neuroparalysis.

Long-range intragenomic RNA–RNA interactions in the genomes of positive-strand RNA viruses involve direct nucleotide base pairing and can span distances of thousands of nucleotides. In this Review, Nicholson and White discuss recent insights into the structure and function of these genomic features and highlight their diverse roles in the gene expression and genome replication of positive-strand RNA viruses.

The protozoan parasiteTrypanosoma bruceihas a single flagellum that is present in all of its different developmental stages. In this Review, Langousis and Hill discuss the structural and functional features of the flagellum and highlight its central role in the virulence and transmission of this important human pathogen.

In this Review, van der Oostet al. summarize the recent structural and biochemical insights into the molecular mechanisms of RNA-guided interference by CRISPR–Cas systems in bacteria and archaea. By comparing the three main types of CRISPR–Cas systems, they highlight the unique and conserved properties of the system and also discuss outstanding questions that require further study.

Bacteria are frequently exposed to subinhibitory concentrations of antibiotics, and recent evidence suggests that this is likely to select for resistance. In this Review, Andersson and Hughes discuss the ecology of antibiotics, the ability of subinhibitory concentrations of antibiotics to select for resistance and the effects of low-level drug exposure on bacterial physiology.

Platelets are multifunctional granulocytes that function at the intersection of antimicrobial and haemostatic host defences. Michael R. Yeaman presents an integrated overview of the antimicrobial functions of platelets, which are mediated both directly and indirectly to integrate innate and adaptive immune responses to pathogens.

One-quarter of the land surface on Earth is underlain by permafrost. Jansson and Taş review the microbial ecology of this fascinating and unique niche, pulling together observations from the study of permafrost isolates and the application of high-throughput sequencing.

Bacterial pathogens have evolved diverse strategies to interfere with and modulate the ubiquitin systems of the host for their own benefit. In this Review, Sasakawa and colleagues discuss the mechanisms that are involved, with a focus on secreted effector proteins that are delivered into the host cell by human bacterial pathogens.

Much of synthetic biology research makes use of model organisms, such asEscherichia coli. Here, Víctor de Lorenzo and colleagues emphasize the need for a wider choice of model organisms and advocate the use of environmental Pseudomonasstrains as model organisms that possess the necessary metabolic traits required to meet current and future synthetic biology and biotechnological needs.

Non-coding RNA devices, such as CRISPR–Cas systems, riboswitches and RNA scaffolds, have emerged as a versatile class of genetic regulatory elements that are used in a broad range of synthetic biology applications. In this Review, Arkin and Qi discuss the design, engineering and application of synthetic non-coding RNA devices for microbial engineering.

Entry of the antimalarial drug precursor semi-synthetic artemisinin into industrial production is the first major milestone for the application of synthetic biology. In this Review, Paddon and Keasling discuss the metabolic engineering and synthetic biology approaches that were used to engineerEscherichia coli and Saccharomyces cerevisiaeto synthesize a precursor of artemisinin, which should aid the development of other pharmaceutical products.

In this Review, Sauer and colleagues outline how microorganisms coordinate common metabolic tasks. By illustrating the information transfer and flux adaptation for key regulatory circuits inEscherichia coli, Bacillus subtilisand yeast, they conclude that cells rely on a few conserved metabolites to report on their global metabolic status and mount appropriate responses.

Although once thought to be clonal, and thus undergo asexual reproduction, accumulating evidence now suggests that many human fungal pathogens retain sexual reproductive machinery and undergo sexual or parasexual reproduction. Iuliana V. Ene and Richard J. Bennett discuss the sexual cycles of three of the most prominent human pathogens —Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus.

The causative agent of whooping cough,Bordetella pertussis, has recently re-emerged as a serious public health concern. Here, Cotter, Miller and colleagues discuss the pathogenesis of pertussis, the shortcomings of current vaccines and the future challenges that need to be addressed for the development of more effective therapeutic strategies.

Wild populations of bacteria and archaea show high levels of genotypic diversity. In this Review, Cordero and Polz discuss recent studies that show that this diversity arises owing to social and ecological interactions, which have important consequences for microbial ecology and population dynamics.

Mortality from influenza viruses is strongly linked to secondary bacterial invaders. Here, Jonathan A. McCullers reviews viral and bacterial virulence factors that contribute to the pathogenesis of co-infections by disrupting physical barriers, dysregulating immune responses and delaying a return to homeostasis.

Paracrystalline arrays of proteins decorate the surface of many bacteria. In this Review, Fagan and Fairweather discuss recent insights into the structural and functional properties of these surface layers, which are beginning to reveal their importance for the growth and survival of many species.

Varicella zoster virus is so well adapted to its human host that studying its pathogenesis heavily relies on human tissue transplants in immunodeficient mice. Here, Arvin and colleagues describe insights from these models that show how this viral pathogen orchestrates host cell and tissue functions to its own advantage.

In this Review, Claverys and colleagues describe the divergent and common principles that govern the transformation process in phylogenetically distinct bacteria and discuss the potential role of imported DNA in generating genetic diversity. They also discuss how this information can be used for the prediction of new transformable species.

Termites depend on an intricate symbiosis with flagellated protists, archaea and bacteria in their guts for the digestion of lignocellulose. Here, Andreas Brune gives an overview of the diversity of the termite microbiota and highlights important microbial processes in the gut microecosystem and their implications for host nutrition.