About this Research Topic
It is not surprising that prophylactic/therapeutic approaches with the aim to modulate the microbiota composition are being pursued, for example, the administration of probiotic bacteria, which are among the applied functional food ingredients. There is convincing evidence that lactobacilli, bifidobacteria, probiotic E. coli strains and other probiotic strains, possess certain health benefits for the host. Recent research indicates that live and proliferating bacteria are not the prerequisite to obtain health-promoting effects. In experimental studies, the beneficial effect was also achieved by inactivated bacteria or bacteria-secreted outer membrane vesicles (OMVs) or certain effector molecules located on the bacterial surface (e.g. peptidoglycan and polysaccharides), secreted by bacteria (e.g. antibacterial peptides) or released after bacterial lysis (e.g. proteins, exopolysaccharides, and DNA). These effector molecules with the defined structure are collectively called postbiotics. Postbiotics exhibit certain benefits over life bacteria for the prophylactic/therapeutic application in terms of safety, defined chemical structure, and longer shelf life.
Until now, variously defined postbiotics with anti-inflammatory, immunomodulatory, neuroprotective, anti-obesogenic, anti-hypertensive, hypocholesterolemic, anti-proliferative, and antioxidant activities have been identified. However, our understanding of the link between defined postbiotic and its biological effect on the host is still incomplete.
It is worth mentioning that postbiotics have become also an important target for modern nutritional strategies. Although yoghurt, kefir or pickled vegetables are naturally abundant in postbiotics in situ, some postbiotics e.g. dextran or nisin have been directly implemented to certain food. Specific postbiotics can function as food biopreservatives, in food packaging or biofilm control. However, the interaction of postbiotics and the food matrix requires more careful investigation.
Along these lines, further research concerning the precise characterization of non-living parts of probiotic bacteria, such as their OMVs, specific effector molecules or metabolites, which shed light on the molecular mechanism involved in the interaction between probiotics and the host, is needed. This research will pave the way to the development of novel therapeutic approaches to promote animal and human health.
With this Research Topic, we aim to gather a collection of articles that cover the most recent research on:
• non-viable probiotic bacteria and probiotic bacteria-derived outer membrane vesicles
• metabolites produced by probiotics such as short-chain fatty acids, indole, conjugated linoleic acid, and bacteriocins
• defined antigens (exopolysaccharides, glycolipids, peptidoglycan, polar lipids, proteins, DNA, (lipo)teichoic acid) isolated from probiotic strains
that covers all aspect from:
• synthesis,
• structural analysis,
• biological activity,
• health benefits,
• application.
The submission is opened to any article format accepted by Frontiers in Microbiology.
Keywords: Bifidobacterium, Lactobacillus, probiotics, postbiotics, vesicles, exopolysaccharides, peptidoglycan
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.