Probiotics are defined as live microorganisms, which when administered in adequate amounts, confer a health benefit on the host. Health benefits have mainly been demonstrated for specific probiotic strains of the following genera: Lactobacillus, Bifidobacterium, Saccharomyces, Enterococcus, Streptococcus, Pediococcus, Leuconostoc, Bacillus, Escherichia coli. The human microbiota is getting a lot of attention today and research has already demonstrated that alteration of this microbiota may have far-reaching consequences. One of the possible routes for correcting dysbiosis is by consuming probiotics. The credibility of specific health claims of probiotics and their safety must be established through science-based clinical studies. This overview summarizes the most commonly used probiotic microorganisms and their demonstrated health claims. As probiotic properties have been shown to be strain specific, accurate identification of particular strains is also very important. On the other hand, it is also demonstrated that the use of various probiotics for immunocompromised patients or patients with a leaky gut has also yielded infections, sepsis, fungemia, bacteraemia. Although the vast majority of probiotics that are used today are generally regarded as safe and beneficial for healthy individuals, caution in selecting and monitoring of probiotics for patients is needed and complete consideration of risk-benefit ratio before prescribing is recommended.

https://www.mdpi.com/1660-4601/11/5/4745/pdf

Microorganisms with claimed probiotic properties: an overview of recent literature.

The ability of probiotic bacteria to adhere to the intestinal epithelium play an important role in colonization of the gastrointestinal tract, preventing their elimination by peristalsis and providing a competitive advantage in this ecosystem. To identify bacterial traits related to adhesion the probiotic strain L. acidophilus M92 was examined for autoaggregation ability and cell surface hydrophobicity L. acidophilus M92 exhibits a strong autoaggregation phenotype and also coaggregation with some pathogen microorganisms that may form a barrier that prevents their colonization. The examined probiotic strain manifests a good degree of hydrophobicity determined by microbial adhesion to hydrocarbons. Aggregation and hydrophobicity were abolished upon exposure of the cells to pronase, which suggests the possible role of cell surface layer (S-layer) proteins, approximated at 45 kDa, in a L. acidophilus M92. The relationship between autoaggregation and adhesion ability to intestinal tissue was investigated by observing the adhesivity of L. acidophilus M92 to porcine ileal epithelial cells. Removal of the S-layer proteins by extraction with 5 M LiCl reduced autaggregation and in vitro adhesion of this strain.

Adhesion and aggregation ability of probiotic strain Lactobacillus acidophilus M92

Advantages and challenges of the spray-drying technology for the production of pure drug particles and drug-loaded polymeric carriers

Probiotic based products are associated with many health benefits. However, the main problem is the low survival of these microorganisms in food products and in gastrointestinal tract. Providing probiotics with a physical barrier is an efficient approach to protect microorganisms and to deliver them into the gut. In our opinion, microencapsulation is one of the most efficient methods, and has been under especial consideration and investigation. However, there are still many challenges to overcome with respect to the microencapsulation process. This review focuses mainly on the methodological approach of probiotic encapsulation including materials and results obtained using encapsulated probiotic in food matrices and different pathologies in animal models. Industrial relevance The inclusion of probiotics into food matrices is one of the most challenging lines of research in food technology. Probiotics in general, and some strains in particular, have a low resistance to different environmental conditions, such as oxygen, light or temperature. Thus, the protection and isolation of the microorganism from the food matrix and the environmental condition are crucial for the development of new probiotic food. In this sense, microencapsulation has gained an increasing interest, since it has been demonstrated that it could protect the bacteria not only during its production process but also during its incorporation into the food matrix, also with protective effects during storage. In conclusion, microencapsulation is of great interest since it could allow a wider application of probiotics in the food market, actually restricted to fresh or powder products.

Microencapsulation of bacteria: A review of different technologies and their impact on the probiotic effects

Several lactic acid bacteria (LAB) isolates from the Lactobacillus genera have been applied in food preservation, partly due to their antimicrobial properties. Their application in the control of human pathogens holds promise provided appropriate strains are scientifically chosen and a suitable mode of delivery is utilized. Urinary tract infection (UTI) is a global problem, affecting mainly diabetic patients and women. Many uropathogens are developing resistance to commonly used antibiotics. There is a need for more research on the ability of LAB to inhibit uropathogens, with a view to apply them in clinical settings, while adhering to strict selection guidelines in the choice of candidate LAB. While several studies have indicated the ability of LAB to elicit inhibitory activities against uropathogens in vitro, more in vivo and clinical trials are essential to validate the efficacy of LAB in the treatment and prevention of UTI. The emerging applications of LAB such as in adjuvant therapy, oral vaccine development, and as purveyors of bioprotective agents, are relevant in infection prevention and amelioration. Therefore, this review explores the potential of LAB isolates and their bacteriocins to control uropathogens, with a view to limit clinical use of antibiotics.

https://www.mdpi.com/1420-3049/22/8/1255/pdf

Lactic Acid Bacteria and Their Bacteriocins: Classification, Biosynthesis and Applications against Uropathogens: A Mini-Review.

Antimicrobial peptides (AMPs) are a class of small peptides that widely exist in nature and they are an important part of the innate immune system of different organisms. AMPs have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses. The emergence of antibiotic-resistant microorganisms and the increasing of concerns about the use of antibiotics resulted in the development of AMPs, which have a good application prospect in medicine, food, animal husbandry, agriculture and aquaculture. This review introduces the progress of research on AMPs comprehensively and systematically, including their classification, mechanism of action, design methods, environmental factors affecting their activity, application status, prospects in various fields and problems to be solved. The research progress on antivirus peptides, especially anti-coronavirus (COVID-19) peptides, has been introduced given the COVID-19 pandemic worldwide in 2020.

/pdf/antimicrobial-peptides-classification-design-application-and-583uqkcpz5.pdf

Antimicrobial Peptides: Classification, Design, Application and Research Progress in Multiple Fields

19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p < 0.05). In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5%) and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture.

/pdf/improvement-of-the-texture-of-yogurt-by-use-of-437jbaxt5a.pdf

Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria.

Antimicrobial activity against Shigella sonnei and probiotic properties of wild lactobacilli from fermented food

Physicochemical characterization and antitumour activity of exopolysaccharides produced by Lactobacillus casei SB27 from yak milk.

Scope Milk-derived extracellular vesicles (mEVs) as nanoparticles are being developed as novel drug vehicles due to their pivotal role in cell-cell communication. As an important bioactive component in milk, little is known about their effect on the gut microbiota and intestinal immunity. Therefore, the effects of mEVs on gut microbiota and intestinal immunity in mice are investigated. Methods and results First, a new method to obtain high-yield mEVs is developed. Afterward, the colonic contents from C57BL/6 mice fed different doses of mEVs (8 weeks) are collected and the microbial composition via 16S rRNA gene sequencing is analyzed. It is found that mEVs could alter the gut microbiota composition and modulate their metabolites-short-chain fatty acids (SCFAs). Furthermore, the effects of mEVs on intestinal immunity are evaluated. It is observed that the expression levels of Muc2, RegIIIγ, Myd88, GATA4 genes, and IgA, sIgA are increased in the intestine, which are significant for the integrity of the mucus layer. Conclusion These findings reveal that the genes with critical importance for intestinal barrier function and immune regulation are modified in mice by oral administration mEVs, which also result in the changes of the relative composition of gut microbiome and SCFAs.

Huaxi Yi

Papers

Antimicrobial Peptides: Classification, Design, Application and Research Progress in Multiple Fields

Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria.

Antimicrobial activity against Shigella sonnei and probiotic properties of wild lactobacilli from fermented food

Physicochemical characterization and antitumour activity of exopolysaccharides produced by Lactobacillus casei SB27 from yak milk.

Oral Administration of Bovine Milk-Derived Extracellular Vesicles Alters the Gut Microbiota and Enhances Intestinal Immunity in Mice