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Exopolysaccharides from probiotic bacteria and their health potential.
Angelin, J, Kavitha, M
International journal of biological macromolecules. 2020;:853-865
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Abstract
Exopolysaccharides (EPS) are extracellular macromolecules excreted as tightly bound capsule or loosely attached slime layer in microorganisms. They play most prominent role against desiccation, phagocytosis, cell recognition, phage attack, antibiotics or toxic compounds and osmotic stress. In the last few decades, natural polymers have gained much attention among scientific communities owing to their therapeutic potential. In particular the EPS retrieved from probiotic bacteria with varied carbohydrate compositions possess a plenty of beneficial properties. Different probiotic microbes have unique behavior in expressing their capability to display significant health promoting characteristics in the form of polysaccharides. In this new era of alternative medicines, these polysaccharides are considered as substitutes for synthetic drugs. The EPS finds applications in various fields like textiles, cosmetics, bioremediation, food and therapeutics. The present review is focused on sources, chemical composition, biosynthetic pathways of EPS and their biological potential. More attention has been given to the scientific investigations on antimicrobial, antitumor, anti-biofilm, antiviral, anti-inflammatory and immunomodulatory activities.
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Recent Insights on the Maternal Microbiota: Impact on Pregnancy Outcomes.
Di Simone, N, Santamaria Ortiz, A, Specchia, M, Tersigni, C, Villa, P, Gasbarrini, A, Scambia, G, D'Ippolito, S
Frontiers in immunology. 2020;:528202
Abstract
Hormonal changes during and after pregnancy are linked with modifications in the maternal microbiota. We describe the importance of the maternal microbiota in pregnancy and examine whether changes in maternal microbiotic composition at different body sites (gut, vagina, endometrium) are associated with pregnancy complications. We analyze the likely interactions between microbiota and the immune system. During pregnancy, the gastrointestinal (gut) microbiota undergoes profound changes that lead to an increase in lactic acid-producing bacteria and a reduction in butyrate-producing bacteria. The meaning of such changes needs clarification. Additionally, several studies have indicated a possible involvement of the maternal gut microbiota in autoimmune and lifelong diseases. The human vagina has its own microbiota, and changes in vaginal microbiota are related to several pregnancy-related complications. Recent studies show reduced lactobacilli, increased bacterial diversity, and low vaginal levels of beta-defensin 2 in women with preterm births. In contrast, early and healthy pregnancies are characterized by low diversity and low numbers of bacterial communities dominated by Lactobacillus. These observations suggest that early vaginal cultures that show an absence of Lactobacillus and polymicrobial vaginal colonization are risk factors for preterm birth. The endometrium is not a sterile site. Resident endometrial microbiota has only been defined recently. However, questions remain regarding the main components of the endometrial microbiota and their impact on the reproductive tract concerning both fertility and pregnancy outcomes. A classification based on endometrial bacterial patterns could help develop a microbiota-based diagnosis as well as personalized therapies for the prevention of obstetric complications and personalized treatments through nutritional, microbiotic, or pharmaceutical interventions.
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Natural and engineered promoters for gene expression in Lactobacillus species.
Peirotén, Á, Landete, JM
Applied microbiology and biotechnology. 2020;(9):3797-3805
Abstract
Lactobacillus species are attractive hosts for the expression of heterologous proteins, antigens, vaccines, and drugs due to their GRAS (generally recognized as safe) status. The bioengineering techniques open new possibilities of improving Lactobacillus strains. In this regard, the control of the gene expression in Lactobacillus strains through the adequate native or engineered promoters acquires a key role in the development of biotechnological applications and for their function as probiotic bacteria. Depending on the objective sought, the protein produced and the strain used, inducible or constitutive promoters can be chosen. Whereas, when a fine-tuning of gene expression is required, the development of synthetic promoter libraries could be the best approach. In this work, we revise the main constitutive and inducible natural promoters from Lactobacillus strains or from other genus that have been applied in Lactobacillus, as well as the few engineered promoters developed for these bacteria.
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Critical insights into antibiotic resistance transferability in probiotic Lactobacillus.
Das, DJ, Shankar, A, Johnson, JB, Thomas, S
Nutrition (Burbank, Los Angeles County, Calif.). 2020;:110567
Abstract
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, with respect to metabolism, immune function, and nutrition. Any perturbation of these beneficial microbes leads to gut dysbiosis, which triggers the development of various disorders in the gastrointestinal system. Probiotics play a key role in resolving the dysbiosis posed by external factors such as antibiotics, other substances, or interventions. Supplementing probiotics with antibiotics is favorable in reducing the harmful effects of antibiotics on gut flora. These microbes also possess specific intrinsic drug resistance mechanisms that aid their survival in the internal environment. According to US Food and Drug Administration reports, species belonging to Lactobacillus and Bifidobacterium genera are the most common probiotics consumed by humans through commercial products. However, various studies have reported the tendency of microbes to acquire specific drug resistance, in recent years, through various mechanisms. The reports on transferable resistance among probiotics are of major concern, of which minimal information is available to date. The aim of this review was to describe the pros and cons of drug resistance among these beneficial microorganisms with emphasis on the recommended selection criteria for specific probiotics, devoid of transferable drug resistance genes, suitable for human consumption.
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Fourteen steps to relevance: taking probiotics from the bench to the consumer.
Reid, G
Canadian journal of microbiology. 2020;(1):1-10
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Abstract
Much is made of the need to translate scientific research into improved care of people or other life forms. Grant applications invariably start with the extent of a problem and end by claiming that their work will or could result in making an impact. In truth, very few projects ever lead to translation at the level of the host, nor was that really their intent. For those who are focused on applied science, there are many ways to reach the desired goal, sometimes through serendipity or by logical stepwise progress. The following paper will provide personal insight into the stages, pitfalls, and ultimate assessment of relevance in the context of using probiotic lactobacilli for human health and other applications.
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Lactobacillus-Derived Bioactive Metabolites for the Regulation of Periodontal Health: Evidences to Clinical Setting.
Sulijaya, B, Takahashi, N, Yamazaki, K
Molecules (Basel, Switzerland). 2020;(9)
Abstract
BACKGROUND Gut microbiota plays a pivotal role in regulating host metabolism that affects the systemic health. To date, several studies have confirmed the fact that microbiota interacts with host, modulating immunity, controlling the homeostasis environment, and maintaining systemic condition. Recent studies have focused on the protective function of poly unsaturated fatty acids, 10-oxo-trans-11-oxadecenoic acid (KetoC) and 10-hydroxy-cis-12-octadecenoic acid (HYA), generated by gut microbiota on periodontal disease. Nevertheless, the mechanism remains unclear as investigations are limited to in vivo and in vitro studies. In this present review, we found that the administration of metabolites, KetoC and HYA, by a probiotic gut microbiota Lactobacillus plantarum from linoleic acid is found to inhibit the oxidation process, possess an antimicrobial function, and prevent the inflammation. These findings suggest the promising use of functional lipids for human health. CONCLUSION Protective modalities of bioactive metabolites may support periodontal therapy by suppressing bacterial dysbiosis and regulating periodontal homeostasis in the clinical setting.
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The Evolution of Human Probiotics: Challenges and Prospects.
Trush, EA, Poluektova, EA, Beniashvilli, AG, Shifrin, OS, Poluektov, YM, Ivashkin, VT
Probiotics and antimicrobial proteins. 2020;(4):1291-1299
Abstract
In recent years, the intestinal microbiota has been found to greatly influence a number of biological processes important for human health and longevity. Microbial composition changes easily in response to external factors, such as an unbalanced diet, lack of physical activity, and smoking. Probiotics are a key factor in maintaining the optimal composition of the intestinal microbiota. However, a number of important questions related to probiotics, such as indication for prescription, comparative efficacy of monostrain and multistrain probiotics, methods of delivery, and shelf life, remain unresolved. The aim of this review is to highlight existing issues regarding probiotic production and their prescription. The review presents the most recent findings regarding advantages and efficacy of monostrain and multistrain probiotics, preservation of probiotic strains in capsules and microcapsules, production of probiotics in the form of biofilms for improved efficacy and survival, and results of clinical studies evaluating the benefits of probiotics against different pathologies. We believe that this work will be of interest to physicians and researchers alike and will promote the development of new probiotics and ensuing regimens aimed at the treatment of various diseases.
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The potential of proteins, hydrolysates and peptides as growth factors for Lactobacillus and Bifidobacterium: current research and future perspectives.
Zhang, C, Zhang, Y, Li, H, Liu, X
Food & function. 2020;(3):1946-1957
Abstract
Probiotics are live microorganisms that provide health benefits to the host when consumed in adequate concentrations. The strains most frequently used as probiotics include Lactobacillus and Bifidobacteria. Probiotics have demonstrated significant potential as therapeutic options for various diseases. In addition to oligosaccharides, proteins, hydrolysates and peptides have also been shown function as prebiotics to promote the growth of probiotics. Therefore, this review provides a summary of the available information and current knowledge on the effects of various proteins on probiotics, focusing on how proteins influence probiotics, although uncertainties and disagreements about how the metabolism of proteins promotes probiotics still exist. Understanding the relationship between proteins and probiotics will allow appropriate prebiotic selection and the development of effective methods to promote the proliferation of probiotics.
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Cholesterol-Lowering Effects of Lactobacillus Species.
Khare, A, Gaur, S
Current microbiology. 2020;(4):638-644
Abstract
Probiotics are the living and non-pathogenic microbial supplements which, upon administration in adequate quantities, influence the host organism positively by improving gut health and enhancing intestinal mucosal integrity. They suppress potentially pathogenic microorganisms by competing with them for nutrients as well as space for gut adherence. Lactobacillus species are the most commonly used bacteria in the probiotic preparations and studies show that they have cholesterol-lowering effects on the hosts. Lipids are biological molecules that are insoluble in water and bile salts play a major role in their digestion as they are synthesized and conjugated to taurine or glycine in the liver. Bile salt hydrolase deconjugates taurine or glycine from bile salts. Cholesterol metabolism is influenced by the effect of Lactobacillus species on microbial populations as well as overall metabolic activity of human intestinal microflora. Deconjugation of bile salt, concentration of short-chain fatty acids and molar proportion of propionate constitute the major processes by which cholesterol lowering is brought about by Lactobacillus species. This review summarizes the cholesterol-lowering properties of this species. A significant number of Lactobacillus strains have been known to display substantial bile salt hydrolase activities and identifying those strains for use in therapeutic purposes can be a great advancement. Here, this identification is done using phylogenetic relationship for different identified potential probiotic Lactobacillus strains.
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Clinical effects of Lactobacillus strains as probiotics in the treatment of irritable bowel syndrome. Results from the LAPIBSS trial: Future objectives.
Maixent, JM, Pons, O, Sennoune, SR, Sadrin, S
Cellular and molecular biology (Noisy-le-Grand, France). 2020;(3):211-214
Abstract
The objective of this communication is to present and analyze the recent results from the LAPIBSS study in order to improve future clinical trials on the effects of Lactobacillus strains in the treatment of irritable bowel syndrome (IBS). Using a tightly-controlled clinical trial protocol with the highest Jadad score of 5/5, the current trial aimed to demonstrate the efficacy of a 2-strain mixture of Lactobacillus acidophilus (L. acidophilus) to improve IBS symptoms. Eighty patients diagnosed with IBS according to Rome III criteria were recruited to a multicentric, double-blind, in parallel groups, placebo-controlled, randomized clinical trial. Patients were provided with a daily dose of two capsules containing either two probiotic strains (5 x 109 cfu/capsule) or placebo for 8 weeks. The primary endpoint was abdominal pain score assessed with a 100-mm visual analogue scale (VAS). Secondary endpoints included scores of bloating, flatus and rumbling assessed with a 100-mm VAS, a composite score that consisted of the sum of the 4 VAS scores, and the stool frequency and consistency assessed with the Bristol Stool Form Scale. Our study has failed to demonstrate a significant improvement of the primary endpoint of abdominal pain. Significant differences between groups were observed for flatus score at week 4 (P=0.04) and week 8 (P=0.03) and for composite score at week 8 (P=0.04). The consumption of the 2-strain mixture of L. acidophilus over 8 weeks is safe, significantly decreases flatus and composite scores. The significant effect on flatus could result from the species-specific homofermentative properties of L. acidophilus strains. The negative results on abdominal pain and the gained experience are discussed for the future clinical trials in IBS.