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Human milk oligosaccharides (HMOs) are complex glycans that are abundant in human milk. The potential impact of a maternal diet on individual HMOs and the association with secretor status is unknown. Thus, this study is aimed to examine the association between maternal diet and HMO profiles.

The gastrointestinal tract of mammals hosts a high and diverse number of different microorganisms, known as intestinal microbiota. Many probiotics were originally isolated from the gastrointestinal tract, and they were defined by the Food and Agriculture Organization of the United Nations (FAO)/WHO as “live microorganisms which when administered in adequate amounts confer a health benefit on the host.” Probiotics exert their beneficial effects on the host through four main mechanisms: interference with potential pathogens, improvement of barrier function, immunomodulation and production of neurotransmitters, and their host targets vary from the resident microbiota to cellular components of the gut–brain axis. However, in spite of the wide array of beneficial mechanisms deployed by probiotic bacteria, relatively few effects have been supported by clinical data. In this regard, different probiotic strains have been effective in antibiotic‐associated diarrhea or inflammatory bowel disease for instance. The aim of this review was to compile the molecular mechanisms underlying the beneficial effects of probiotics, mainly through their interaction with the intestinal microbiota and with the intestinal mucosa. The specific benefits discussed in this paper include among others those elicited directly through dietary modulation of the human gut microbiota.

Bifidobacteria are bacterial gut commensals of mammals, birds and social insects that are perceived to influence the metabolism/physiology of their host. In this context, members of the Bifidobacterium bifidum species are believed to significantly contribute to the overall microbiota of the human gut at infant stage. However, the molecular reasons for their adaptation to this environment are poorly understood. In this study, we analysed the pan-genome of B.bifidum species by decoding genomes of 15 B.bifidum strains, which highlighted the existence of a conserved gene uniquely present in this bifidobacterial taxon, underscoring a nutrient acquisition strategy that targets host-derived glycans, such as those present in mucin. Growth experiments and corresponding transcriptomic analyses confirmed the in silico data and supported these intriguing and unique host glycan-specific saccharolytic features. The ubiquity of the genetic features of B.bifidum for the breakdown of host glycans was confirmed by interrogating metagenomic datasets, thereby supporting the notion that metabolic access to host-derived glycans is a potent evolutionary force that has shaped B.bifidum genomes and consequently the ecology of the infant intestinal microbiota. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

[Aims] The purpose of this study was to investigate the heat-shock response at molecular level in Lactobacillus rhamnosus GG, Bifidobacterium animalis subsp. lactis BB-12 and their heat-tolerant derivatives and to characterize the changes that make the derivatives more robust in terms of heat stress., [Methods and results] The study strains were exposed for 2 h to a heat-shock treatment, Bif. animalis subsp. lactis BB-12 and its derivative at 50°C and the Lact. rhamnosus GG and its derivative at 60°C. Protein synthesis before and after heat shock was examined using proteomics and RT-qPCR. The analysis revealed that the regulation of seven proteins in both strain pairs was modified as a response to heat or between the original and the derivative strain. The comparison of wild-type strains and the heat-tolerant derivatives suggests that the acquisition of heat tolerance in the Bif. animalis subsp. lactis BB-12 derivative is due to a slightly increased constitutive level of chaperones, while in Lact. rhamnosus GG derivative, the main reason seems to be a higher ability to induce the production of chaperones., [Conclusions] This study revealed possible markers of heat tolerance in B. lactis and Lact. rhamnosus strains., [Significance and impact of study] This study increases our knowledge on how Lactobacillus and Bifidobacterium strains may acquire heat tolerance. These findings may be useful for improving the heat tolerance of existing probiotic strains as well as screening new heat-tolerant strains.

Probiotic products constitute one of the most successful segments of the functional foods market. Recent regulations developed in different countries require extensive documentation from human studies before a health claim can be approved for a food product. This gives a new direction to this research area and underlines the need for products with a high functional efficacy. Most of the current probiotic products target the general population, whilst those formulated for specific human groups are still lacking. Some individuals or patient groups present particular nutritional needs and require nutritionally adapted products, thus constituting an opportunity for the development of specifically formulated foods. In this context, it is critical to identify both the target populations that may benefit the most from such products, and the specific probiotic properties that fulfil the requirements of such populations. Human groups that can benefit from this joint development include groups of extreme age and patients suffering from diseases in which intestinal microbiota and/or immune modulation may have beneficial effects. The development of such target-specific probiotic foods, by including strains rationally selected for a specific health benefit, tailor-made for a certain target population, into nutritionally optimal products constitutes a challenge for the food industry. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.