Dear Colleagues,

There are two convergent origins of the living organisms now described as probiotics. Historically, these were microorganisms safely consumed through fermented foods. Many of these bacteria were known as lactic acid producers which were able to inhibit the growth of other, mostly pathogenic, microorganisms. They were later considered as probiotics, which, according to their definition, act through diverse mechanisms to confer a health benefit to the host. However, the modern approach to probiotics came from studies on microbiomes of the higher organisms and on the important role of the microbiome in the integrity and functions of the host. The microbiome contributes to the early-life imprinting, particularly through its effects on the developing immune system. The members of the microbiome, soon after successful gut colonization, come into direct crosstalk with the body surface’s epithelial cells, inducing transcriptional changes in the epithelium, causing differences in multiple gene expression. The microbiome plays an important role in the regulation of the immune response in the innate and mucosal immune systems and contributes to colonization resistance in different niches of the host. All these properties have led to the concept that the microbiome, distorted in many conditions and diseases, can be restored by administering beneficial microorganisms isolated from healthy microbiomes. These were originally represented by the Lactobacillus and Bifidobacterium genera. The availability of whole-genome sequencing and the era of genomics has enabled the elucidation of the mechanisms of probiotic efficacy and could help to discover and characterize new strains of microorganisms with probiotic properties among those residing in the microbiome. A new and inquisitive look at these bacteria has resulted in an enormous wave of research and development in the prospective field of probiotics. It soon appeared that probiotics can be useful not only in correcting distorted microbiota but also to facilitate and direct microbiota development in human and animal newborns. Since more and more microorganisms of the healthy microbiome with probiotic properties have been described and characterized in recent years, the original list of several probiotic strains belonging to a few species has been lengthened to hundreds, and it is growing prospectively. The mechanisms by which probiotic microorganisms positively interact with host organisms appeared not to be exclusively linked to viable cells, which has opened a new field of postbiotics, i.e., non-viable bacterial cells, their components and metabolites presenting most of the probiotic properties. Since postbiotics share many health-promoting activities of the probiotics but have more broad application potential, it is expected that they will stimulate a wide spectrum of research on their characteristics and mechanisms of action in different hosts.

This Special Issue aims to gather original publications and reviews on probiotics and postbiotics from all fields of research based on in vitro and in vivo studies.

In this Special Issue, original research articles and reviews are welcome. Research areas may include (but are not limited to) the following fields: medical, veterinary, food (human and animal), vertebrate and non-vertebrate biology, and environmental influence on their taxonomy, genetics, metabolism, functionality, and effects exerted on host organisms: position in microbiome and microbiota, interactions with other microorganisms and crosstalk with host cells including immune-competent cells, and effects on innate immunity mechanisms

I look forward to receiving your contributions.

Prof. Dr. Piotr B. Heczko
Guest Editor

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• probiotics
• postbiotics
• taxonomy
• genomics
• proteomics
• metabolomics
• microbiome
• immunity
• tissue
• animals

• Effects of Probiotics on Health, 2nd Edition in Microorganisms (1 article)