Jun Wang

Immune-microbe interactions early in life influence the risk of allergies, asthma, and other inflammatory diseases. Breastfeeding guides healthier immune-microbe relationships by providing nutrients to specialized microbes that in turn benefit the host's immune system. Such bacteria have co-evolved with humans but are now increasingly rare in modern societies. Here we show that a lack of bifidobacteria, and in particular depletion of genes required for human milk oligosaccharide (HMO) utilization from the metagenome, is associated with systemic inflammation and immune dysregulation early in life. In breastfed infants given Bifidobacterium infantis EVC001, which expresses all HMO-utilization genes, intestinal T helper 2 (Th2) and Th17 cytokines were silenced and interferon β (IFNβ) was induced. Fecal water from EVC001-supplemented infants contains abundant indolelactate and B. infantis-derived indole-3-lactic acid (ILA) upregulated immunoregulatory galectin-1 in Th2 and Th17 cells during polarization, providing a functional link between beneficial microbes and immunoregulation during the first months of life.

Food safety is increasingly becoming an important public health issue, as foodborne diseases present a widespread and growing public health problem in both developed and developing countries. The rapid and precise monitoring and detection of foodborne pathogens are some of the most effective ways to control and prevent human foodborne infections. Traditional microbiological detection and identification methods for foodborne pathogens are well known to be time consuming and laborious as they are increasingly being perceived as insufficient to meet the demands of rapid food testing. Recently, various kinds of rapid detection, identification, and monitoring methods have been developed for foodborne pathogens, including nucleic-acid-based methods, immunological methods, and biosensor-based methods, etc. This article reviews the principles, characteristics, and applications of recent rapid detection methods for foodborne pathogens.

Understanding binding properties at protein-protein interfaces has been limited to structural and mutational analyses of natural binding partners or small peptides identified by phage display. Here, we present a high-resolution analysis of a nonpeptidyl small molecule, previously discovered by medicinal chemistry [Tilley, J. W., et al. (1997) J. Am. Chem. Soc. 119, 7589-7590], which binds to the cytokine IL-2. The small molecule binds to the same site that binds the IL-2 alpha receptor and buries into a groove not seen in the free structure of IL-2. Comparison of the bound and several free structures shows this site to be composed of two subsites: one is rigid, and the other is highly adaptive. Thermodynamic data suggest the energy barriers between these conformations are low. The subsites were dissected by using a site-directed screening method called tethering, in which small fragments were captured by disulfide interchange with cysteines introduced into IL-2 around these subsites. X-ray structures with the tethered fragments show that the subsite-binding interactions are similar to those observed with the original small molecule. Moreover, the adaptive subsite tethered many more compounds than did the rigid one. Thus, the adaptive nature of a protein-protein interface provides sites for small molecules to bind and underscores the challenge of applying structure-based design strategies that cannot accurately predict a dynamic protein surface.

Foodborne pathogens are the main factors behind foodborne diseases and food poisoning and thus pose a great threat to food safety.