Probiotics and Psychobiotics: the Role of Microbial Neurochemicals

A Narrative Review on the Advance of Probiotics to Metabiotics

Recently, the term metabiotics has emerged as a new concept of probiotics. This concept entails combining existing probiotic components with metabolic by-products improve specific physiological functionalities. Representative ingredients of these metabiotics include short-chain fatty acids (SCFAs), bacteriocins, polysaccharides, and peptides. The new concept is highly regarded as it complements the side effects of existing probiotics and is safe and easy to administer. Known health functions of metabiotics are mainly immune regulation, anti-inflammatory, anticancer, and brain-neurological health. Research has been actively conducted on the health benefits related to the composition of intestinal microorganisms. Among them, the focus has been on brain neurological health, which requires extensive research. This study showed that neurological disorders, such as depression, anxiety, autism spectrum disorder, Alzheimer's disease, and Parkinson's disease, can be treated and prevented according to the gut-brain axis theory by changing the intestinal microflora. In addition, various studies are being conducted on the immunomodulatory and anticancer effects of substances related to metabiotics of the microbiome. In particular, its efficacy is expected to be confirmed through human studies on various cancers. Therefore, developing various health functional effects of the next-generation probiotics such as metabiotics to prevent or treatment of various diseases is anticipated.

Bifidobacterium breve M-16V regulates the autonomic nervous system via the intestinal environment: A double-blind, placebo-controlled study

We conducted a randomized controlled trial to investigate the potential of Bifidobacterium breve M-16 V to improve mood in humans. In this evaluation, we incorporated the use of near-infrared spectroscopy (NIRS), which has been used to evaluate mood states in studies with small sample sizes. Participants were given B. breve M-16 V (20 billion cells/day) for 6 weeks, and their mood state was assessed before and after ingestion. NIRS data were collected at rest and during a mental arithmetic task (under stress). Intake of B. breve M-16 V decreased the heart rate under stress and increased levels of the GABA-like substance pipecolic acid in stool samples. In addition, B. breve M-16 V improved mood and sleep scores in participants with high anxiety levels. These results suggest that B. breve M-16 V affects the metabolites of the gut microbiota and has the potential to modulate the autonomic nervous system and to improve mood and sleep.

Microbiota-Gut-Brain Axis and Antidepressant Treatment

In the treatment of depressive disorders, conventional antidepressant therapy has been the mainstay of clinical management, along with well-established nonpharmacological interventions such as various kinds of psychotherapy. Over the last 2 decades, there has been considerable interest in the role of the gastrointestinal system and its microbiota on brain function, behavior, and mental health. Components of what is referred to as the microbiota-gut-brain axis have been uncovered, and further research has elicited functional capabilities such as "gut-brain modules." Some studies have found associations with compositional alterations of gut microbiota in patients with depressive disorders and individuals experiencing symptoms of depression. Regarding the pathogenesis and neurobiology of depression itself, there appears to be a multifactorial contribution, in addition to the theories involving deficits in catecholaminergic and monoamine neurotransmission. Interestingly, there is evidence to suggest that antidepressants may play a role in modulating the gut microbiota, thereby possibly having an impact on the microbiota-gut-brain axis in this manner. The development of prebiotics, probiotics, and synbiotics has led to studies investigating not only their impact on the microbiota but also their therapeutic value in mental health. These psychobiotics have the potential to be used as therapeutic adjuncts in the treatment of depression. Regarding future directions, and in an attempt to further understand the role of the microbiota-gut-brain axis in depression, more studies such as those involving fecal microbiota transplantation will be required. In addition to recent findings, it is also suggested that more research will have to be undertaken to elicit whether specific strains of gut organisms are linked to depression. In terms of further investigation of the therapeutic potential of prebiotics, probiotics, and synbiotics as adjuncts to antidepressant treatment, we also expect there to be more research targeting specific microorganisms, as well as a strong focus on the effects of specific prebiotic fibers from an individualized (personalized) point of view.

Impact of Microbiome-Brain Communication on Neuroinflammation and Neurodegeneration

The gut microbiome plays a pivotal role in maintaining human health, with numerous studies demonstrating that alterations in microbial compositions can significantly affect the development and progression of various immune-mediated diseases affecting both the digestive tract and the central nervous system (CNS). This complex interplay between the microbiota, the gut, and the CNS is referred to as the gut-brain axis. The role of the gut microbiota in the pathogenesis of neurodegenerative diseases has gained increasing attention in recent years, and evidence suggests that gut dysbiosis may contribute to disease development and progression. Clinical studies have shown alterations in the composition of the gut microbiota in multiple sclerosis patients, with a decrease in beneficial bacteria and an increase in pro-inflammatory bacteria. Furthermore, changes within the microbial community have been linked to the pathogenesis of Parkinson's disease and Alzheimer's disease. Microbiota-gut-brain communication can impact neurodegenerative diseases through various mechanisms, including the regulation of immune function, the production of microbial metabolites, as well as modulation of host-derived soluble factors. This review describes the current literature on the gut-brain axis and highlights novel communication systems that allow cross-talk between the gut microbiota and the host that might influence the pathogenesis of neuroinflammation and neurodegeneration.

Gut brain regulation using psychobiotics for improved neuropsychological illness

"Psychobiotics" are a novel class of probiotics that are beneficial to the health and functional efficiency of our brain and psychology. The main hold on command in ill conditions of the brain and psychology is overtaken by these psychobiotic bacteria (a dietary supplement) via the action/determined role of bacterial neurochemicals or neuroactive substances that are released by them in the intestinal epithelium after their ingestion. Although these psychobiotics flourish in the gut of the host consuming them, the effect is widely spread to the brain due to the communication between the gut and the brain via the bidirectional gut-brain axis. The nervous system involved in this directional process includes both the enteric nervous system and the central nervous system. With time, several corroborations have proved the effectiveness of psychobiotics in terms of mental illnesses and brain disorders. In the prevailing situation of the coronavirus pandemic, psychobiotics may serve as an aid because a majority of the population worldwide is already suffering from psychological issues due to changes in lifestyle and dietary habits, and in need of an immediate solution to cope with it. Moreover, the in silico approach is also vital for the development of biological relevance to neurosubstances.

Heat-Killed L. helveticus Enhances Positive Mood States: A Randomized, Double-Blind, Placebo-Controlled Study

When mood states are impaired, daily life is severely disrupted. To maintain a specific mood state, both positive and negative moods must be controlled; however, methods to maintain a positive mood have not been fully established. Previous studies have suggested that heat-killed L. helveticus MCC1848 has the potential to improve positive moods. This study aimed to test the efficacy of heat-killed L. helveticus MCC1848 in maintaining and improving a positive mood with PANAS, a questionnaire specifically designed to assess positive and negative mood, as the primary endpoint. Healthy Japanese nursing students (n = 46) were randomized to receive heat-killed L. helveticus MCC1848 (5 billion/day) or placebo powder for four weeks. Mood state was assessed before and two and four weeks after the intervention began; ingestion of heat-killed L. helveticus MCC1848 significantly improved PANAS 'Positive Affect' compared to the placebo. These results indicate that heat-killed L. helveticus MCC1848 is effective in enhancing positive mood.

Heat-killed Lactobacillus helveticus improves mood states: a randomised, double-blind, placebo-controlled study

We investigated the effects of heat-killed Lactobacillus helveticus MCC1848 on daily mood states in healthy young adults. Participants (n=58) were randomised to receive heat-killed L. helveticus MCC1848 powder or placebo powder for 4 weeks. During the study period, adverse events were recorded in the participant diary. Mood states were assessed before and 2 and 4 weeks after initiation of the intervention. The primary outcomes were the shortened version of the Profile of Mood States 2 (POMS 2) scores. Secondary outcomes included other mood state (State-Trait Anxiety Inventory (STAI); visual analogue scale (VAS)), quality of life (acute form of the SF-36v2), sleep (Athens Insomnia Scale (AIS)) and fatigue (Chalder Fatigue Scale (CFS)) scores. Four weeks of heat-killed L. helveticus MCC1848 intake, compared to placebo, significantly improved the shortened version of the POMS 2 'friendliness' and the VAS 'relaxed' scores, which are two indicators of positive mood states. On the other hand, heat-killed L. helveticus MCC1848 intake had no significant effects on negative mood state items (e.g. anger, nervousness, confusion) assessed by the shortened version of the POMS 2, STAI and VAS. AIS and CFS scores also showed no significant differences. No adverse effects were observed with 4 weeks of heat-killed L. helveticus MCC1848 intake. These results suggest that daily consumption of heat-killed L. helveticus MCC1848 is safe and has the potential to improve positive mood states. UMIN Clinical Trial Registry: UMIN000043697.

Whole-Genome Sequence of Lactococcus lactis Subsp. lactis LL16 Confirms Safety, Probiotic Potential, and Reveals Functional Traits

Safety is the most important criteria of any substance or microorganism applied in the food industry. The whole-genome sequencing (WGS) of an indigenous dairy isolate LL16 confirmed it to be Lactococcus lactis subsp. lactis with genome size 2,589,406 bp, 35.4% GC content, 246 subsystems, and 1 plasmid (repUS4). The Nextera XT library preparation kit was used to generate the DNA libraries, and the sequencing was carried out on an Illumina MiSeq platform. In silico analysis of L. lactis LL16 strain revealed non-pathogenicity and the absence of genes involved in transferable antimicrobial resistances, virulence, and formation of biogenic amines. One region in the L. lactis LL16 genome was identified as type III polyketide synthases (T3PKS) to produce putative bacteriocins lactococcin B, and enterolysin A. The probiotic and functional potential of L. lactis LL16 was investigated by the presence of genes involved in adhesion and colonization of the host's intestines and tolerance to acid and bile, production of enzymes, amino acids, and B-group vitamins. Genes encoding the production of neurotransmitters serotonin and gamma-aminobutyric acid (GABA) were detected; however, L. lactis LL16 was able to produce only GABA during milk fermentation. These findings demonstrate a variety of positive features that support the use of L. lactis LL16 in the dairy sector as a functional strain with probiotic and GABA-producing properties.

Feed additives of bacterial origin as an immunoprotective or imunostimulating factor

Since January 2006 when using antibiotics as growth promoters in animal feed have been banned scientists are looking for the best resolution to apply alternative substances. Extensive research into the health-promoting properties of probiotics and prebiotics has led to significant interest in the mechanisms of action of the combined administration of these feed additives as a synbiotic. Subsequent research has led to the development of new products. Among the most important health benefits of additives are, inhibiting the growth of pathogenic bacteria in the GI tract, maintenance of homeostasis, treatment of inflammatory bowel diseases, and increase in immunity. Specific immunomodulatory mechanisms of action are not well understood and the effect is not always positive, though there are no reports of adverse effects of these substances found in the literature. For this reason, research is still being conducted on their proper application. However, due to the difficulties of carrying out research on humans, evidence of the beneficial effect of these additives comes mainly from experiments on animals. The objective of the present work was to assess the effect of probiotics, prebiotics, and synbiotics, as well as new additives including postbiotics, proteobiotics, nutribiotics, and pharmabiotics, on specific immunomodulatory mechanisms of action, increase in immunity, the reduction of a broad spectrum of diseases.

Biochemical and Genomic Characterization of Two New Strains of Lacticaseibacillus paracasei Isolated from the Traditional Corn-Based Beverage of South Africa, Mahewu, and Their Comparison with Strains Isolated from Kefir Grains

Lacticaseibacillus paracasei (formerly Lactobacillus paracasei) is a nomadic lactic acid bacterium (LAB) that inhabits a wide variety of ecological niches, from fermented foodstuffs to host-associated microenvironments. Many of the isolated L. paracasei strains have been used as single-strain probiotics or as part of a symbiotic consortium within formulations. The present study contributes to the exploration of different strains of L. paracasei derived from non-conventional isolation sources-the South African traditional fermented drink mahewu (strains MA2 and MA3) and kefir grains (strains KF1 and ABK). The performed microbiological, biochemical and genomic comparative analyses of the studied strains demonstrated correlation between properties of the strains and their isolation source, which suggests the presence of at least partial strain adaptation to the isolation environments. Additionally, for the studied strains, antagonistic activities against common pathogens and against each other were observed, and the ability to release bioactive peptides with antioxidant and angiotensin I-converting enzyme inhibitory (ACE-I) properties during milk fermentation was investigated. The obtained results may be useful for a deeper understanding of the nomadic lifestyle of L. paracasei and for the development of new starter cultures and probiotic preparations based on this LAB in the future.

Isolation and Characterization of Lactobacillus crispatus, Lactococcus lactis, and Carnobacterium divergens as Potential Probiotic Bacteria from Fermented Black and Green Olives (Olea europaea): An Exploratory Study

Background

Table olives are becoming well recognized as a source of probiotic bacteria that might be used to create a health-promoting fermented food product by traditional procedures based on the activities of indigenous microbial consortia present in local environments. Methodology. In the present study, the characterization of probiotic bacteria isolated from mince, chunks, and brine of fermented green and black olives (Olea europaea) was done based on morphological, biochemical, and physiological characteristics.

Results

Bacterial isolates demonstrated excellent survival abilities at 25, 37, and 45°C and at a variable range of pH. However, the optimum temperature is 37 and the optimum pH is 7 for all three isolates. An antimicrobial susceptibility pattern was found among these isolates through the disc diffusion method. Most of the isolates were susceptible to streptomycin, imipenem, and chloramphenicol, whereas, amoxicillin showed resistance to these isolates, and variable results were recorded for the rest of the antibiotics tested. The growth of the isolates was optimum with the supplementation of 3% NaCl and 0.3% bile salt. The isolated bacteria were able to ferment skimmed milk into yogurt, hence making it capable of producing organic acid.

Conclusion

Isolates of Lactobacillus crispatus MB417, Lactococcus lactis MB418 from black olives, and Carnobacterium divergens MB421 from green olives were characterized as potential candidates for use as starter cultures to induce fermentation of other probiotic food products.

Microalgae in Terms of Biomedical Technology: Probiotics, Prebiotics, and Metabiotics

Green, red, brown, and diatomic algae, as well as cyanobacteria, have been in the focus of attention of scientists and technologists for over 5 decades. This is due to their importance as efficient and economical producers of food additives, cosmetics, pharmaceuticals, biofertilizers, biofuels, and wastewater bioremediation agents. Recently, the role of microalgae has increasingly been considered in terms of their probiotic function, i.e., of their ability to normalize the functioning of the microbiota of humans and agricultural animals and to produce biologically active substances, including hormones, neurotransmitters, and immunostimulators. A separate brief subsection of the review deals with the potential functions of microalgae with respect to the brain and psyche, i.e., as psychobiotics. Moreover, algal polysaccharides and some other compounds can be broken down to short fragments that will stimulate the development of useful intestinal microorganisms, i.e., function as efficient prebiotics. Finally, many components of microalgal cells and chemical agents produced by them can exert important health-promoting effects per se, which indicates that they are as potentially valuable metabiotics (the term preferred by late Prof. B.A. Shenderov), which are alternatively denoted as postbiotics in the literature.

A New Concept of Associations between Gut Microbiota, Immunity and Central Nervous System for the Innovative Treatment of Neurodegenerative Disorders

Nerve cell death accounts for various neurodegenerative disorders, in which altered immunity to the integrated central nervous system (CNS) might have destructive consequences. This undesirable immune response often affects the progressive neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, schizophrenia and/or amyotrophic lateral sclerosis (ALS). It has been shown that commensal gut microbiota could influence the brain and/or several machineries of immune function. In other words, neurodegenerative disorders may be connected to the gut-brain-immune correlational system. The engrams in the brain could retain the information of a certain inflammation in the body which might be involved in the pathogenesis of neurodegenerative disorders. Tactics involving the use of probiotics and/or fecal microbiota transplantation (FMT) are now evolving as the most promising and/or valuable for the modification of the gut-brain-immune axis. More deliberation of this concept and the roles of gut microbiota would lead to the development of stupendous treatments for the prevention of, and/or therapeutics for, various intractable diseases including several neurodegenerative disorders.

Lactobacilli: Legal Regulation and Prospects for New Generation Drugs

The global probiotics industry has been undergoing major changes in recent years. Approaches to finding and creating new probiotics, as well as a paradigm of their use in food, medicine, and pharmacology are changing. The catalyst proved to be the increasing popularity and availability of omics technologies, in particular, metagenomic studies of human and animal microbiomes. However, the efficiency and safety of drugs based on probiotic strains, as well as their marketing rates, largely depend on the levels of legal and technical regulation in the field. The present review discusses the aspects of legal regulation in Russia, the European Union and the United States, along with the advantages and disadvantages of probiotics and postbiotics. A consensus is emerging that postbiotics have a number of advantages over classical live probiotic cultures. The review also focuses on the lactobacilli family, which includes the largest number of probiotic strains studied so far and still holds a leading position among probiotics. On the legislative front, Russia is often ahead of its time with adopting such laws as the Federal Law No. 492-FZ on biosecurity, which defined the concept of human and animal microbiota and set forth legislative guidelines for its preservation. The new field of research referred to as microbiome nutrigenomics aims to achieve this goal.

Consumption of fermented dairy products is associated with lower anxiety levels in Azorean university students

A growing number of studies have found that the gut microbiota is involved in a variety of psychological processes and neuropsychiatric disorders, which include mood and anxiety disorders. Consumption of dairy products may contain bioactive compounds and probiotic bacteria with various therapeutic benefits. The aim of the study was to investigate possible associations between the frequency of consumption of different types of dairy products and the state of anxiety in university students. The subjects were 311 Azorean university students, 231 women and 80 men, with an average age of 20.5 years. Subjects completed a quantitative questionnaire on the frequency of dairy product consumption and a short version of the Spielberger State-Trait Anxiety Inventory (STAI) test. Among dairy products, semi-skimmed milk was the most commonly consumed, followed by cheese (ripened), drinking yogurt, skim milk, and set yogurt, while fresh cheese, whole milk, and dairy ice cream were the least common. Discriminant analysis showed that consumption of fermented products (yogurt and cheese) was significantly higher (P < 0.05) in the group with low anxiety level (score <40 in STAI test) than in the group with higher anxiety level (score ≥ 40). In this analysis, 62.4% of the initially grouped cases were correctly classified according to the frequency of fermented products consumption. No correlations were found between anxiety and unfermented dairy products. The results indicate that the consumption of fermented dairy products has a positive effect on reducing anxiety in young Azorean university students.

Lactic Acid Bacteria in Raw-Milk Cheeses: From Starter Cultures to Probiotic Functions

Traditional cheeses produced from raw milk exhibit a complex microbiota, characterized by a sequence of different microorganisms from milk coagulation and throughout maturation. Lactic acid bacteria (LAB) play an essential role in traditional cheese making, either as starter cultures that cause the rapid acidification of milk or as secondary microbiota that play an important role during cheese ripening. The enzymes produced by such dynamic LAB communities in raw milk are crucial, since they support proteolysis and lipolysis as chief drivers of flavor and texture of cheese. Recently, several LAB species have been characterized and used as probiotics that successfully promote human health. This review highlights the latest trends encompassing LAB acting in traditional raw milk cheeses (from cow, sheep, and goat milk), and their potential as probiotics and producers of bioactive compounds with health-promoting effects.

Postbiotic Gamma-Aminobutyric Acid and Camel Milk Intervention as Innovative Trends Against Hyperglycemia and Hyperlipidemia in Streptozotocin-Induced C57BL/6J Diabetic Mice

Diabetes is a serious disease that threatens human health worldwide. The study hypothesis is to investigate the novel trends that may aid in the prevention of diabetic complications. Camel milk was presented as traditional functional food, and Lactobacillus brevis KLDS_1.0727 and KLDS_1.0373 strains were shown to synthesize postbiotic Gamma-aminobutyric acid as a potential food additive, which can therapeutically intervene against hyperglycemia and hyperlipidemia in streptozotocin-induced C₅₇BL/6J mice. During a four-week timeframe, body weight and postprandial blood glucose levels were monitored. Post-euthanasia, blood plasma was obtained to investigate hyperlipidemia, insulin concentrations, liver, and renal functions. The liver, pancreas, kidney, and spleen underwent histopathological examinations. The results demonstrated that KLDS_1.0727 and KLDS_1.0373 (LAC_S1, LAC_S2) and camel milk treatments all had a significant influence on hypoglycemic activity, as evidenced by reduced postprandial blood glucose levels. LAC_S1, LAC_S2, and camel milk therapy significantly reduced blood hypolipidemic, and some liver enzymes such as (alanine aminotransferase and aspartate transaminase) levels. Therefore, we recommend consuming camel milk regularly and expanding its use with fermented foods containing L. brevis, one of the probiotics capable of producing gamma-aminobutyric acid (GABA) as future food additives that can improve human health and reduce the prevalence of several diseases disorders.

How to Improve Health with Biological Agents-Narrative Review

The proper functioning of the human organism is dependent on a number of factors. The health condition of the organism can be often enhanced through appropriate supplementation, as well as the application of certain biological agents. Probiotics, i.e., live microorganisms that exert a beneficial effect on the health of the host when administered in adequate amounts, are often used in commonly available dietary supplements or functional foods, such as yoghurts. Specific strains of microorganisms, administered in appropriate amounts, may find application in the treatment of conditions such as various types of diarrhoea (viral, antibiotic-related, caused by Clostridioides difficile), irritable bowel syndrome, ulcerative colitis, Crohn’s disease, or allergic disorders. In contrast, live microorganisms capable of exerting influence on the nervous system and mental health through interactions with the gut microbiome are referred to as psychobiotics. Live microbes are often used in combination with prebiotics to form synbiotics, which stimulate growth and/or activate the metabolism of the healthy gut microbiome. Prebiotics may serve as a substrate for the growth of probiotic strains or fermentation processes. Compared to prebiotic substances, probiotic microorganisms are more tolerant of environmental conditions, such as oxygenation, pH, or temperature in a given organism. It is also worth emphasizing that the health of the host may be influenced not only by live microorganisms, but also by their metabolites or cell components, which are referred to as postbiotics and paraprobiotics. This work presents the mechanisms of action employed by probiotics, prebiotics, synbiotics, postbiotics, paraprobiotics, and psychobiotics, together with the results of studies confirming their effectiveness and impact on consumer health.

Effect of fermented foods on some neurological diseases, microbiota, behaviors: mini review

Fermented foods are among the traditional foods consumed for centuries. In recent years, awareness of fermented foods has been increasing due to their positive health benefits. Fermented foods contain beneficial microorganisms. Fermented foods, such as kefir, kimchi, sauerkraut, and yoghurt, contain Lactic acid bacteria (LAB), such as Lactobacilli, Bifidobacteria, and their primary metabolites (lactic acid). Although studies on the effect of consumption of fermented foods on diabetes, cardiovascular, obesity, gastrointestinal diseases on chronic diseases have been conducted, more studies are needed regarding the relationship between neurological diseases and microbiota. There are still unexplored mechanisms in the relationship between the brain and intestine. In this review, we answer how the consumption of fermented foods affects the brain and behavior of Alzheimer's disease, Parkinson's disease, multiple sclerosis disease, stroke, and gut microbiota.

Paraprobiotics in Non-Surgical Periodontal Therapy: Clinical and Microbiological Aspects in a 6-Month Follow-Up Domiciliary Protocol for Oral Hygiene

Periodontal disease represents a progressive destruction of tooth-supporting tissues. Recently, paraprobiotics are regarded as an adjunctive therapy to the non-surgical Scaling-and-Root-Planing (SRP). The aim of this study is to evaluate the efficacy of two new formulations of paraprobiotics, a toothpaste and a mouthwash, respectively, for the domiciliary hygiene. A total of 40 patients were randomly assigned to the following domiciliary treatments: Group 1 (SRP + Curasept Intensive Treatment 0.2% chlorhexidine) (control) and Group 2 (SRP + Biorepair Peribioma toothpaste + Biorepair Peribioma Mousse mouthwash) (trial). At baseline (T₀) and after 3 and 6 months (T₁–T₂), periodontal clinical (Bleeding on Probing, Probing Pocket Depth, Clinical Attachment Loss, Bleeding Score, Sulcus Bleeding Index, Plaque Index, Approximal Plaque Index, Adherent Gingiva, Gingival Recession, and Pathological Sites) and microbiological parameters (Pathological Bacteria, Saprophytic Bacteria, Enlarged Red Complex, Red Complex, Orange Complex, and counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensys, Treponema denticola, Prevotella intermedia, and Fusobacterium nucleatum). The use of the experimental products resulted in a significant reduction of most of the clinical indices assessed, which occurred at a major degree with respect to the conventional chlorhexidine considered as control. Additionally, after 6 months of use, the abovementioned products significantly decreased the percentage of pathological bacteria and the counts of those bacteria constituting the “Red Complex”, more related to the periodontal disease. Accordingly, the paraprobiotics-based products tested in this study seem to represent a valid support to SRP with a benefit on both clinical indices and on specific periodontopathogens.

Genome Features of Probiotic Bifidobacteria Determining Their Strain-Specific Properties

The aim of the study was to analyze the genome features of the probiotic strains Bifidobacterium longum 379, Bifidobacterium bifidum 1, and Bifidobacterium bifidum 791 and study their antiviral activity.

Materials and Methods

Whole genome sequencing of three strains of bifidobacteria was performed on the MiSeq platform (Illumina Inc., USA). The genomes were annotated using the Prokka v. 1.11 utility and RAST genomic server. The individual genetic determinants were searched using the ResFinder 3.2, PathogenFinder, PlasmidFinder, RAST, and Bagel 4 software. The antiviral activity of the strains against influenza A viruses was studied using MDCK cells (Madin-Darby canine kidney cells), the epidemic strain of influenza A/Lipetsk/1V/2018 (H1N1 pdm09) (EPI_ISL_332798), the highly pathogenic avian influenza virus A/common gull/Saratov/1676/2018 (H5N6) strain (EPI_ISL_336925), and neutral red vital dye.

Results

The genomes of all studied strains contained determinants responsible for utilization of carbohydrates of plant origin; the genes of key enzymes for the synthesis of tryptophan and folic acid are present in the genomes of B. longum 379 and B. bifidum 791. A feature of the B. bifidum 791 genome is the presence of determinants responsible for the synthesis of thermostable type I bacteriocins - flavucin and lasso peptide. The B. bifidum 791 strain was found to show pronounced antiviral activity against both the strains of influenza A, the supernatant of which suppressed viral replication in vitro up to a dilution of 1:8, and the cells inhibited viral reproduction up to a concentration of 6·106 CFU/ml.

Conclusion

The analysis of complete genomes of B. longum 379, B. bifidum 1, and B. bifidum 791 showed features that determine their strain-specific properties, the findings on which were previously made empirically based on indirect signs. In the genomes of B. longum 379 and B. bifidum 791 strains, in contrast to B. bifidum 1 strain, key enzymes for the synthesis of tryptophan and folic acid were found. These substances have an impact on the human body in many ways, including having a thymoleptic effect (reducing emotional stress, irritability, anxiety, eliminating lethargy, apathy, melancholy, anxiety) and regulating cognitive activity. The presence of determinants responsible for the synthesis of thermostable type I bacteriocins in the genome of B. bifidum 791 strain determines its pronounced antiviral activity.

Treating autism spectrum disorder by intervening with gut microbiota

Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders with a high prevalence in childhood. The gut microbiota can affect human cognition and moods and has a strong correlation with ASD. Microbiota transplantation, including faecal microbiota transplantation (FMT), probiotics, breastfeeding, formula feeding, gluten-free and casein-free (GFCF) diet and ketogenic diet therapy, may provide satisfying effects for ASD and its related various symptoms. For instance, FMT can improve the core symptoms of ASD and gastrointestinal symptoms. Probiotics, breastfeeding and formula feeding, and GFCF diet can improve gastrointestinal symptoms. The core symptom score still needs to be confirmed by large-scale clinical randomized controlled studies. It is recommended to use a ketogenic diet to treat patients with epilepsy in ASD. At present, the unresolved problems include which of gut the microbiota are beneficial, which of the microorganisms are harmful, how to safely and effectively implant beneficial bacteria into the human body, and how to extract and eliminate harmful microorganisms before transplantation. In future studies, large sample and randomized controlled clinical studies are needed to confirm the mechanism of intestinal microorganisms in the treatment of ASD and the method of microbial transplantation.

Novel Insights for Metabiotics Production by Using Artisanal Probiotic Cultures

Wild probiotic consortia of microorganisms (bacteria and yeasts) associated in the artisanal cultures' microbiota (milk kefir grains, water kefir grains and kombucha) are considered valuable promoters for metabiotics (prebiotics, probiotics, postbiotics and paraprobiotics) production. The beneficial effects of the fermented products obtained with the artisanal cultures on human well-being are described by centuries and the interest for them is continuously increasing. The wild origin and microbial diversity of these above-mentioned consortia give them extraordinary protection capacity against microbiological contaminants in unusual physico-chemical conditions and unique fermentative behaviour. This review summarizes the state of the art for the wild artisanal cultures (milk and water kefir grains, respectively, kombucha-SCOBY), their symbiotic functionality, and the ability to ferment unconventional substrates in order to obtain valuable bioactive compounds with in vitro and in vivo beneficial functional properties. Due to the necessity of the bioactives production and their use as metabiotics in the modern consumer's life, artisanal cultures are the perfect sources able to biosynthesize complex functional metabolites (bioactive peptides, antimicrobials, polysaccharides, enzymes, vitamins, cell wall components). Depending on the purposes of the biotechnological fermentation processes, artisanal cultures can be used as starters on different substrates. Current studies show that the microbial synergy between bacteria-yeast and/or bacteria-offers new perspectives to develop functional products (food, feeds, and ingredients) with a great impact on life quality.

Roles and Mechanisms of Gut Microbiota in Patients With Alzheimer's Disease

Alzheimer’s disease (AD) is the most common age-related progressive neurodegenerative disease, characterized by a decline in cognitive function and neuronal loss, and is caused by several factors. Numerous clinical and experimental studies have suggested the involvement of gut microbiota dysbiosis in patients with AD. The altered gut microbiota can influence brain function and behavior through the microbiota–gut–brain axis via various pathways such as increased amyloid-β deposits and tau phosphorylation, neuroinflammation, metabolic dysfunctions, and chronic oxidative stress. With no current effective therapy to cure AD, gut microbiota modulation may be a promising therapeutic option to prevent or delay the onset of AD or counteract its progression. Our present review summarizes the alterations in the gut microbiota in patients with AD, the pathogenetic roles and mechanisms of gut microbiota in AD, and gut microbiota–targeted therapies for AD. Understanding the roles and mechanisms between gut microbiota and AD will help decipher the pathogenesis of AD from novel perspectives and shed light on novel therapeutic strategies for AD.

Effect of Lacticaseibacillus paracasei Strain Shirota on Improvement in Depressive Symptoms, and Its Association with Abundance of Actinobacteria in Gut Microbiota

We previously reported lower counts of lactobacilli and Bifidobacterium in the gut microbiota of patients with major depressive disorder (MDD), compared with healthy controls. This prompted us to investigate the possible efficacy of a probiotic strain, Lacticaseibacillus paracasei strain Shirota (LcS; basonym, Lactobacillus casei strain Shirota; daily intake of 8.0 × 10¹⁰ colony-forming units), in alleviating depressive symptoms. A single-arm trial was conducted on 18 eligible patients with MDD or bipolar disorder (BD) (14 females and 4 males; 15 MDD and 3 BD), assessing changes in psychiatric symptoms, the gut microbiota, and biological markers for intestinal permeability and inflammation, over a 12-week intervention period. Depression severity, evaluated by the Hamilton Depression Rating Scale, was significantly alleviated after LcS treatment. The intervention-associated reduction of depressive symptoms was associated with the gut microbiota, and more pronounced when Bifidobacterium and the Atopobium clusters of the Actinobacteria phylum were maintained at higher counts. No significant changes were observed in the intestinal permeability or inflammation markers. Although it was difficult to estimate the extent of the effect of LcS treatment alone, the results indicated that it was beneficial to alleviate depressive symptoms, partly through its association with abundance of Actinobacteria in the gut microbiota.

Does modern research validate the ancient wisdom of gut flora and brain connection? A literature review of gut dysbiosis in neurological and neurosurgical disorders over the last decade

The connection between gastrointestinal microbiota and the brain has been described in ancient medical texts and is now well established by research. It is a bidirectional communication which plays a critical role in regulating not only the gastrointestinal homeostasis but has also been linked to higher emotional and cognitive functions. Recent studies have sought to expand on this concept by providing concrete evidence of the influence of gut microbiome on a wide array of diseases and disorders of the central nervous system. This article reviews the most recent literature published on this subject, over the previous decade and aims to establish the role of a healthy gut microbiome and probiotics as an effective adjunct in health and management of diseases of the nervous system. A literature search on PubMed database was conducted using keywords including "gut brain-axis," "gut dysbiosis," "neuropsychiatric disorders," "neurodegenerative disorders," "probiotic," and "traumatic brain injury." The search was performed without any publication date restrictions. Both animal and human studies evaluating the role of gut dysbiosis on various neurological and neurosurgical diseases, published in peer-reviewed journals, were reviewed. Current studies do not provide conclusive evidence of a direct origin of CNS disorders from gut dysbiosis, but a possible modulatory role of gut microbiota in certain neurological disorders has been implicated. An understanding of this connection can aid in finding novel therapeutic strategies for the management of neurological disorders associated with memory dysfunctions and brain and spinal cord injuries.

Modulatory Effects of Probiotics During Pathogenic Infections With Emphasis on Immune Regulation

In order to inhibit pathogenic complications and to enhance animal and poultry growth, antibiotics have been extensively used for many years. Antibiotics applications not only affect target pathogens but also intestinal beneficially microbes, inducing long-lasting changes in intestinal microbiota associated with diseases. The application of antibiotics also has many other side effects like, intestinal barrier dysfunction, antibiotics residues in foodstuffs, nephropathy, allergy, bone marrow toxicity, mutagenicity, reproductive disorders, hepatotoxicity carcinogenicity, and antibiotic-resistant bacteria, which greatly compromise the efficacy of antibiotics. Thus, the development of new antibiotics is necessary, while the search for antibiotic alternatives continues. Probiotics are considered the ideal antibiotic substitute; in recent years, probiotic research concerning their application during pathogenic infections in humans, aquaculture, poultry, and livestock industry, with emphasis on modulating the immune system of the host, has been attracting considerable interest. Hence, the adverse effects of antibiotics and remedial effects of probiotics during infectious diseases have become central points of focus among researchers. Probiotics are live microorganisms, and when given in adequate quantities, confer good health effects to the host through different mechanisms. Among them, the regulation of host immune response during pathogenic infections is one of the most important mechanisms. A number of studies have investigated different aspects of probiotics. In this review, we mainly summarize recent discoveries and discuss two important aspects: (1) the application of probiotics during pathogenic infections; and (2) their modulatory effects on the immune response of the host during infectious and non-infectious diseases.

Probiotic potential of γ-aminobutyric acid (GABA)-producing yeast and its influence on the quality of cheese

Kazakh cheese is a traditional dairy product in Xinjiang, China. To study the function and potential probiotic characteristics of yeast in Kazakh cheese and its contribution to cheese fermentation, we screened the γ-aminobutyric acid (GABA)-producing yeasts Pichia kudriavzevii 1-21, Kluyveromyces marxianus B13-5, Saccharomyces cerevisiae DL6-20, and Kluyveromyces lactis DY1-10. We investigated the potential probiotic properties of these strains and their use in cheese fermentation (cheeses designated CSP, CSM, CSS, and CSI, respectively); a control with no added yeast was designated CS. The results showed that the 4 yeast strains all showed high self-polymerization (2- and 24-h autoaggregation capacity of >80 and 90%, respectively), hydrophobicity (40-92% variation, low hydrophobicity in xylene, but within the range of probiotics), and the ability to survive the gastrointestinal tract (survival rate >75% after simulation), indicating the probiotic ability of the strains in vitro. The GABA production capacity of the CSM cheese increased (to 95.6 mg/100 g), but its protein content did not change significantly, and amino acid degradation was obvious. The GABA production capacity of the CSS cheese decreased (to 450 mg/kg); its protein content declined, and its amino acid content increased. Except for water and protein, we found no obvious differences in most physical and chemical indicators. Kluyveromyces marxianus B13-5 helped to form the desired texture. Multivariate statistical analysis showed that fermentation of the cheese with the 4 yeasts improved the production of esters and alcohols. The CSS cheese had good aroma production performance, because S. cerevisiae DL6-20 produced high concentrations of isoamyl alcohol, hexanoic acid ethyl ester, benzyl alcohol, octanoic acid ethyl ester, 3-hydroxy-2-butanone, and hexanoic acid; the content of 2-methyl-propanoic acid was low. Compared with the CSP cheese, the CSI and CSM cheeses had a fruitier aroma and a milder odor, but the CSI and CSM cheeses had high concentrations of ethyl acetate, butanoic acid, ethyl ester, 3-methyl-1-butanol-acetate, ethyl hexanoate, ethyl octanoate, acetic acid 2-phenylethyl ester, and ethyl lactate; concentrations of 3-methyl-butanoic acid, propanoic acid, acetic acid, and butanoic acid were low. The CSP cheese had stronger acid-producing ability. The order of fragrance production performance was CSS > CSI, CSM > CSP > CS. Research into the fermentation mechanisms of GABA-producing yeast in cheese will provide a theoretical basis for the quality control and industrial production of Kazakh cheese.

The Adult Phenylketonuria (PKU) Gut Microbiome

Phenylketonuria (PKU) is an inborn error of phenylalanine metabolism primarily treated through a phenylalanine-restrictive diet that is frequently supplemented with an amino acid formula to maintain proper nutrition. Little is known of the effects of these dietary interventions on the gut microbiome of PKU patients, particularly in adults. In this study, we sequenced the V4 region of the 16S rRNA gene from stool samples collected from adults with PKU (n = 11) and non-PKU controls (n = 21). Gut bacterial communities were characterized through measurements of diversity and taxa abundance. Additionally, metabolic imputation was performed based on detected bacteria. Gut community diversity was lower in PKU individuals, though this effect was only statistically suggestive. A total of 65 genera across 5 phyla were statistically differentially abundant between PKU and control samples (p < 0.001). Additionally, we identified six metabolic pathways that differed between groups (p < 0.05), with four enriched in PKU samples and two in controls. While the child PKU gut microbiome has been previously investigated, this is the first study to explore the gut microbiome of adult PKU patients. We find that microbial diversity in PKU children differs from PKU adults and highlights the need for further studies to understand the effects of dietary restrictions.

GUT MICROBIOTA, PREBIOTICS, PROBIOTICS, AND SYNBIOTICS IN GASTROINTESTINAL AND LIVER DISEASES: PROCEEDINGS OF A JOINT MEETING OF THE BRAZILIAN SOCIETY OF HEPATOLOGY (SBH), BRAZILIAN NUCLEUS FOR THE STUDY OF HELICOBACTER PYLORI AND MICROBIOTA (NBEHPM), AND BRAZILIAN FEDERATION OF GASTROENTEROLOGY (FBG)

Over the last years, there is growing evidence that microorganisms are involved in the maintenance of our health and are related to various diseases, both intestinal and extraintestinal. Changes in the gut microbiota appears to be a key element in the pathogenesis of hepatic and gastrointestinal disorders, including non-alcoholic fatty liver disease, alcoholic liver disease, liver cirrhosis, inflammatory bowel disease, irritable bowel syndrome, and Clostridium difficile - associated diarrhea. In 2019, the Brazilian Society of Hepatology (SBH) in cooperation with the Brazilian Nucleus for the Study of Helicobacter Pylori and Microbiota (NBEHPM), and Brazilian Federation of Gastroenterology (FBG) sponsored a joint meeting on gut microbiota and the use of prebiotics, probiotics, and synbiotics in gastrointestinal and liver diseases. This paper summarizes the proceedings of the aforementioned meeting. It is intended to provide practical information about this topic, addressing the latest discoveries and indicating areas for future studies.

Dopamine in Health and Disease: Much More Than a Neurotransmitter

Dopamine is derived from an amino acid, phenylalanine, which must be obtained through the diet. Dopamine, known primarily to be a neurotransmitter involved in almost any higher executive action, acts through five types of G-protein-coupled receptors. Dopamine has been studied extensively for its neuronal handling, synaptic actions, and in relation to Parkinson's disease. However, dopamine receptors can be found extra-synaptically and, in addition, they are not only expressed in neurons, but in many types of mammalian cells, inside and outside the central nervous system (CNS). Recent studies show a dopamine link between the gut and the CNS; the mechanisms are unknown, but they probably require cells to act as mediators and the involvement of the immune system. In fact, dopamine receptors are expressed in almost any cell of the immune system where dopamine regulates various processes, such as antigen presentation, T-cell activation, and inflammation. This likely immune cell-mediated linkage opens up a new perspective for the use of dopamine-related drugs, i.e., agonist-antagonist-allosteric modulators of dopamine receptors, in a variety of diseases.

Potential in vivo delivery routes of postbiotics

Bioactive micro- and macro-molecules (postbiotics) derived from gut beneficial microbes are among natural chemical compounds with medical significance. Currently, a unique therapeutic strategy has been developed with an emphasis on the small molecular weight biomolecules that are made by the microbiome, which endow the host with several physiological health benefits. A large number of postbiotics have been characterized, which due to their unique pharmacokinetic properties in terms of controllable aspects of the dosage and various delivery routes, could be employed as promising medical tools since they exert both prevention and treatment strategies in the host. Nevertheless, there are still main challenges for the in vivo delivery of postbiotics. Currently, scientific literature confirms that targeted delivery systems based on nanoparticles, due to their appealing properties in terms of high biocompatibility, biodegradability, low toxicity, and significant capability to carry both hydrophobic and hydrophilic postbiotics, can be used as a novel and safe strategy for targeted delivery or/and release of postbiotics in various (oral, intradermal, and intravenous) in vivo models. The in vivo delivery of postbiotics are in their emerging phase and require massive investigation and randomized double-blind clinical trials if they are to be applied extensively as treatment strategies. This manuscript provides an overview of the various postbiotic metabolites derived from the gut beneficial microbes, their potential therapeutic activities, and recent progressions in the drug delivery field, as well as concisely giving an insight on the main in vivo delivery routes of postbiotics.

Altered neurometabolic potential of gut microbiome in healthy children of different age

Recently much attention is paid to investigation of the gut microbiome impact on children's mental health. The study was aimed to detect alterations in the taxonomic composition and content of bacterial genes encoding key enzymes involved in the metabolism of neuroactive compounds in the metagenomes of healthy young children and adolescents. The whole metagenome sequencing was used to obtain the metagenomic data of the faecal specimens. The bioinformatics algorithm developed and the catalogue of homologs created were used to identify the changes in abundance of bacterial genes and metagenomic signatures in the studied metagenomes. The core neurometabolic signature of the healthy children gut microbiota included the Bacteroides uniformis, Faecalibacterium prausnitzii and Lachnospiraceae bacterium species, as well as genes involved in production of acetic, propionic and butyric acids, glutamate and enzymes possessing antioxidant activity. Comparison of metagenomes in children of different age groups revealed significant (p < 0.1) changes in the average abundance for 3 bacterial genera and 18 species. The higher alpha diversity of the adolescents’ microbiota was observed both at the genus and species level. Furthermore, in the adolescents’ microbiota metagenomes the increased average relative abundances for the genes encoding enzymes involved in production of SCFAs, glutamate, tryptophan and compounds with antioxidant properties, histidine degradation and linoleic acid conjugation were observed (p < 0.1). The study results support the evidence that healthy gut microbial communities become more diverse and functional as their human hosts become older.

Probiotics: A Dietary Factor to Modulate the Gut Microbiome, Host Immune System, and Gut-Brain Interaction

Various benefits of probiotics to the host have been shown in numerous human clinical trials. These organisms have been proposed to act by improving the balance of the gut microbiota and enhancing the production of short-chain fatty acids, as well as by interacting with host cells in the gastrointestinal tract, including immune cells, nerve cells, and endocrine cells. Although the stimulation of host cells by probiotics and subsequent signaling have been explained by in vitro experiments and animal studies, there has been some skepticism as to whether probiotics can actually interact with host cells in the human gastrointestinal tract, where miscellaneous indigenous bacteria coexist. Most recently, it has been shown that the ileal microbiota in humans after consumption of a fermented milk is occupied by probiotics for several hours, indicating that there is adequate opportunity for the ingested strain to stimulate the host cells continuously over a period of time. As the dynamics of ingested probiotics in the human gastrointestinal tract become clearer, further progress in this research area is expected to elucidate their behavior within the tract, as well as the mechanism of their physiological effects on the host.

Nutrition and the ageing brain: Moving towards clinical applications

The global increases in life expectancy and population have resulted in a growing ageing population and with it a growing number of people living with age-related neurodegenerative conditions and dementia, shifting focus towards methods of prevention, with lifestyle approaches such as nutrition representing a promising avenue for further development. This overview summarises the main themes discussed during the 3^rd Symposium on "Nutrition for the Ageing Brain: Moving Towards Clinical Applications" held in Madrid in August 2018, enlarged with the current state of knowledge on how nutrition influences healthy ageing and gives recommendations regarding how the critical field of nutrition and neurodegeneration research should move forward into the future. Specific nutrients are discussed as well as the impact of multi-nutrient and whole diet approaches, showing particular promise to combatting the growing burden of age-related cognitive decline. The emergence of new avenues for exploring the role of diet in healthy ageing, such as the impact of the gut microbiome and development of new techniques (imaging measures of brain metabolism, metabolomics, biomarkers) are enabling researchers to approach finding answers to these questions. But the translation of these findings into clinical and public health contexts remains an obstacle due to significant shortcomings in nutrition research or pressure on the scientific community to communicate recommendations to the general public in a convincing and accessible way. Some promising programs exist but further investigation to improve our understanding of the mechanisms by which nutrition can improve brain health across the human lifespan is still required.

Host and Microbial Tryptophan Metabolic Profiling in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that is associated with demyelination and neuronal loss. Over recent years, the immunological and neuronal effects of tryptophan (Trp) metabolites have been largely investigated, leading to the hypothesis that these compounds and the related enzymes are possibly involved in the pathophysiology of MS. Specifically, the kynurenine pathway of Trp metabolism is responsible for the synthesis of intermediate products with potential immunological and neuronal effects. More recently, Trp metabolites, originating also from the host microbiome, have been identified in MS, and it has been shown that they are differently regulated in MS patients. Here, we sought to discuss whether, in MS patients, a specific urinary signature of host/microbiome Trp metabolism can be potentially identified so as to select novel biomarkers and guide toward the identification of specific metabolic pathways as drug targets in MS.

Catabolism of biogenic amines in Pseudomonas species

Biogenic amines (BAs; 2-phenylethylamine, tyramine, dopamine, epinephrine, norepinephrine, octopamine, histamine, tryptamine, serotonin, agmatine, cadaverine, putrescine, spermidine, spermine and certain aliphatic amines) are widely distributed organic molecules that play basic physiological functions in animals, plants and microorganisms. Pseudomonas species can grow in media containing different BAs as carbon and energy sources, a reason why these bacteria are excellent models for studying such catabolic pathways. In this review, we analyse most of the routes used by different species of Pseudomonas (P. putida, P. aeruginosa, P. entomophila and P. fluorescens) to degrade BAs. Analysis of these pathways has led to the identification of a huge number of genes, catabolic enzymes, transport systems and regulators, as well as to understanding of their hierarchy and functional evolution. Knowledge of these pathways has allowed the design and collection of genetically manipulated microbes useful for eliminating BAs from different sources, highlighting the biotechnological applications of these studies.