Reviews & Analysis

In coastal systems mixed metabolic strategies of marine heterotrophic bacteria have implications for how efficiently organic carbon is retained in the marine food web, and how climatically important gases are exchanged between the ocean and the atmosphere. These resourceful heterotrophs use light, either directly or indirectly, to obtain supplemental energy and decrease their reliance on organic matter. This Review highlights these mechanisms and their importance to coastal carbon cycling by marine bacteria.

If stretched end to end, the estimated 10³⁰viruses in the oceans would span farther than the nearest 60 galaxies. This reservoir of genetic and biological diversity continues to yield exciting discoveries and, in this Review, Curtis A. Suttle highlights the areas that are likely to be of greatest interest in the next few years.

Stephen Giovannoni and Ulrich Stingl discuss recent advances in the cultivation of bacterioplankton, and review the new insights into the ecology and physiology of these microorganisms that have been enabled by metagenomic and population studies of cultivated strains.

Microorganisms communicate and cooperate to perform a wide range of multicellular behaviours including biofilm formation. In this Opinion, Kenneth Bayles discusses the role of regulated bacterial cell death and lysis in biofilm development, and how this process is functionally analogous to apoptosis in eukaryotic development.

Soils are highly complex and challenging environments to study. In this Review, Tony O'Donnell and colleagues call for the development of soil microbiology into a systems science. Imaging and modelling techniques are reviewed that together should enable microbial ecologists to examine the implications of spatio–temporal heterogeneity for the dynamics of microbial communities and their physical environments.

AlthoughCampylobacter jejuni is a common foodborne bacterial pathogen, we know less about its biology and pathogenicity than we do about other less prevalent pathogens. Here, we examine the biological factors of C. jejunithat contribute to colonization and disease in humans and chickens.

The discovery of broad structural and functional relationships among host defence effector polypeptides from all biological kingdoms has provided new insights into the immunological roles of these molecules. This Opinion highlights the unifying themes of these host defence molecules by considering their evolutionary past and biomedical future.

Generations of microbiologists have relied on traditional genetic screening techniques to isolate mutants. Nowadays, advances in high-throughput technologies mean that fluorescent assays can be exploited for the rapid isolation of mutants with complex phenotypes. These single-cell techniques, which include flow cytometry and microfluidic applications, and their uses in microbiology, are discussed in this Review.

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.

This Timeline examines the legacy of nineteenth-century microbiology in relation to plant and animal biogeography of the time. The particular focus is Beijerinck's experimental and theoretical work, and what it implies for twentieth century studies of microbial biodiversity and biogeography.

Although microorganisms have gained notoriety as pathogens, many interactions with microorganisms benefit hosts and can affect development, immunity and nutrition. This Review discusses common features of pathogenic and mutualistic interactions that have arisen from studies withXenorhabdus nematophila, which influences the lives of two different host animals.

Several prions have been identified in fungi, where they behave as non-chromosomal cytoplasmic genetic elements that are transmitted from cell to cell during cell fusion. In this Review, Reed B. Wickner and colleagues take an in-depth look at the biology and structure of fungal prions.

The symbiotic relationship between leguminous plants and rhizobial bacteria is one of the most well-studied microbial symbioses. The availability of genome sequence information for many of the bacterial and plant partners involved has been invaluable and in this article, the authors review the most recent discoveries about the mutual recognition betweenSinorhizobium meliloti and Medicago truncatula.

Carbohydrate-binding agents (CBAs) are a family of diverse molecules that can bind to specific glycan structures on viruses or target cells. Jan Balzarini describes a new antiviral mechanism that is based on the specific interaction of CBAs with the glycans that are present on viral-envelope glycoproteins.

RNA pseudoknots have been identified in many different viral and cellular RNAs and are known to have various roles in virus and cellular gene expression. Here, Ian Brierley and colleagues review viral pseudoknots and the role of these structural motifs in virus gene expression and genome replication.

Infections with dengue virus have increased significantly over the past two decades and it is estimated that >3 billion people live in at-risk areas worldwide. Whitehead and colleagues discuss the challenges that are associated with the development of an effective tetravalent dengue vaccine and the progress that has been made towards achieving this goal.

Infections with bacterial pathogens still cause more than 5 million deaths annually. In this article, Stefan Kaufmann discusses how rational vaccine design against bacterial pathogens can benefit from recent insights into the host immune response.

Rotavirus is responsible for >500,000 deaths in children under 5 years of age worldwide annually. Two new vaccines shown to protect against rotavirus gastroenteritis were recently licensed. Angel, Franco and Greenberg review recent advances in our knowledge of the virus, the host immune response to rotavirus infection and the efficacy and safety of the new vaccines.

Vaccine strategies are focused on developing protective responses to immunogenic peptide epitopes of pathogens that are normally recognized by T and B cells. However, some epitopes stimulate crossreactive T-cell responses between pathogens and can prime a host to damaging pathology on infection with the crossreactive pathogen. The removal of potentially pathogenic epitopes from vaccines might enhance prophylaxis and reduce the risk of side effects of vaccine-associated disease.

In addition to improving our understanding of target antigens for vaccines and their correlates of protection, recent advances in immunological research, particularly in our understanding of innate immunity, have also had a major impact on adjuvant research. Bruno Guy reviews the practical applications of our increased understanding of the immune system in the design and development of more specific and focused adjuvants.