Volume 10 Issue 7, July 2012

Viral infections activate immune signalling pathways that suppress the expression of interleukin-12 subunit p40, a cytokine subunit required for efficient clearance of bacterial pathogens.

The addition of glycine residues to the lipid A core of the lipopolysaccharide (LPS) component in theVibrio choleraeO1 El Tor cell wall confers polymyxin B resistance.

InListeriaspp. long antisense RNAs can simultaneously activate and inhibit adjacent operons, representing a novel mechanism of gene regulation in bacteria.

New data reveal howMycobacterium tuberculosisaccesses the macrophage cytosol during infection.

Ustilago maydissecretes an effector protein, Pep1, which inhibits the plant peroxidase POX12 to block the oxidative burst associated with the plant defence response.

Successful infection by enteric pathogens depends on the expression of pathogen virulence genes and the ability of the pathogens to outcompete the gut microbiota for nutrients.

Toxoplasma gondiiTgSORTLR is a cargo receptor that delivers proteins to the rhoptries and micronemes and is essential for the formation of these secretory organelles.

This month's Genome Watch highlights some of the technical challenges that need to be overcome to gain further insight into microbial metatranscriptomes.

Our monthly round up of infectious diseases news, which this month includes a new treatment for amoebic dysentery, a new drug target for cerebral malaria, and a measles outbreak ahead of the Euro 2012 football championship.

Encounters between the replication and transcription machineries occur frequently in bacterial cells and are detrimental to fitness. Here, Grossman, Wang and colleagues review the two different types of replication–transcription conflict and describe the mechanisms that bacteria use to prevent and resolve these conflicts.

Asthma is a heterogeneous, complex disease, and its causes have environmental, immunological, genetic and microbial components. In this Review, Edwardset al. describe how microorganisms can influence the risk, severity and pathogenesis of asthma, and protection against the disease.

Gene transfer agents (GTAs) have been identified in four bacterial and archaeal lineages. These genetic entities resemble phages, but the genes encoding the phage-like structure of the GTA particle are encoded within the genome of the producing cell, and GTAs instead package random pieces of the producing cell's genome. Here, the defining characteristics, potential functions and possible origins of GTAs are reviewed.

The twin-arginine translocation (Tat) protein export system is present in the membranes of most bacteria and archaea and transports folded proteins while maintaining the permeability barrier of the membrane. Here, Palmer and Berks summarize the recent advances in our understanding of how this remarkable system functions.

Like larger organisms, microorganisms display distinct distributions in space and time. Martiny, Hanson and colleagues propose that four processes — selection, drift, dispersal and mutation — can shape such microbial biogeographic patterns, and analyse the literature to assess the evidence for their importance in shaping one pattern, the distance–decay relationship.

Did the cenancestor have a phospholipid membrane? In this Opinion article, Lombard, López-García and Moreira discuss how recent top-down phylogenomic analyses have provided new information to address this question.