Health-promoting Bacteria Research Articles

Bifidobacterium animalis Promotes the Growth of Weaning Piglets by Improving Intestinal Development, Enhancing Antioxidant Capacity, and Modulating Gut Microbiota.

Probiotics are widely used to promote performance and improve gut health in weaning piglets. Therefore, the objective of this study was to investigate the effects of dietary supplementation with Bifidobacterium animalis subsp. lactis (B. animalis) JYBR-190 on the growth performance, intestine health, and gut microbiota of weaning piglets. The results showed that the dietary addition of B. animalis significantly improved growth performance and decreased diarrhea incidence. B. animalis increased villus height in the duodenum and elevated goblet cell numbers and amylase activity in the jejunum. Additionally, B. animalis supplementation markedly increased total antioxidant capacity in jejunal mucosa but declined the malondialdehyde content. B. animalis treatment did not affect the mRNA expressions associated with the intestinal barrier and inflammatory cytokine in various intestinal segments. Microbiota analysis indicated that a diet supplemented with B. animalis significantly increased the relative abundances of health-promoting bacteria in the lumen, such as Streptococcus, Erysipelotrichaceae, Coprococcus, and Oscillibacter. There was a trend for B. animalis fed piglets to have a higher relative abundance of B. animalis in ileal digesta. Moreover, B. animalis-treated pigs decreased the abundance of Helicobacter and Escherichia-Shigella in ileal mucosa-associated microbiota. In summary, this study showed that B. animalis supplementation stimulated growth performance, improved gut development, enriched beneficial bacteria abundances, and declined intestinal pathogens populations, while B. animalis had limited effects on the intestinal barrier and immune function. IMPORTANCE In the modern swine industry, weaning is a critical period in the pig's life cycle. Sudden dietary, social, and environmental changes can easily lead to gut microbiota dysbiosis, diarrhea, and a decrease in growth performance. To stabilize intestinal microbiota and promote animal growth, antibiotics were widely applied in swine diets during the past few decades. However, the side effects of antibiotics posed a great threat to public health and food safety. Therefore, it is urgent to find and develop antibiotic alternatives. The growing evidence suggested that probiotics can be preferable alternatives to antibiotics because they can modulate microbiota composition and resist pathogens colonization. In this study, our results indicated that dietary supplementation with Bifidobacterium animalis promoted growth in weaning piglets by improving gut development, increasing beneficial bacteria abundances, and declining pathogens populations.

Short-term supplementation with ω-3 polyunsaturated fatty acids modulates primarily mucolytic species from the gut luminal mucin niche in a human fermentation system

ABSTRACT Consumption of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provides multifaceted health benefits. Recent studies suggest that ω-3 PUFAs modulate the gut microbiota by enhancing health-promoting bacteria, such as the mucin specialist Akkermansia muciniphila. However, these prebiotic properties have been poorly investigated and direct effects on the gut microbiome have never been explored dynamically across gut regions and niches (lumen vs. mucus-associated microbiota). Thus, we studied the effects of 1 week EPA- and DHA-enriched ω-3 fish-oil supplementation on the composition and functionality of the human microbiome in a Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME®). Gut microbial communities derived from one individual harvested in two different seasons were tested in duplicate. Luminal and outer mucus-associated microbiota of the ileum, ascending, transverse and descending colons were cultivated over 28 d from fecal inoculates and supplemented with ω-3 PUFAs for the last 7 d. We show that ω-3 PUFA supplementation modulates the microbiota in a gut region- and niche-dependent fashion. The outer mucus-associated microbiota displayed a higher resilience than the luminal mucin habitat to ω-3 PUFAs, with a remarkable blooming of Akkermansia muciniphila in opposition to a decrease of Firmicutes-mucolytic bacteria. The ω-3 PUFAs also induced a gradual and significant depletion of non-mucolytic Clostridia members in luminal habitats. Finally, increased concentrations of the short chain fatty acids (SCFA) propionate in colon regions at the end of the supplementation was associated positively with the bloom of Akkermansia muciniphila and members of the Desulfovibrionia class.

A diet high in FODMAPs as a novel dietary strategy in diabetes?

Dietary patterns have a profound effect on shaping the gut microbiota. Diverse populations of intestinal bacteria mediate their health-related effects through fermentation of short-chain carbohydrates to produce short-chain fatty acids (SCFAs) which have both pro-inflammatory and anti-inflammatory effects. Type 2 diabetes (T2D) is a disease characterized by chronic inflammation and both microbiota and SCFA have been implicated. Dietary intervention is a cornerstone for controlling body weight, insulin secretion, and postprandial glycemic response. The term FODMAPs stands for poorly-absorbed fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. The health benefits of FODMAPS mainly came from research on gastrointestinal disease where the reduced intake of poorly absorbed FODMAP alleviated symptoms of irritable bowel syndrome albeit with an alteration in gut microbiota. Despite a large amount of literature on dietary intervention in T2D, the health-related effects of FODMAPs have not been explored in this high-risk population. Thus, apart from reducing quantity, modulating the quality of different carbohydrates may reduce glucose absorption and alter the balance of health-related gut microbiota in our pursuit of prevention and treatment of type 2 diabetes. In this review, we summarize the evidence of individual FODMAP contents which influence the pathogenic processes of T2D, especially in the diverse populations of intestinal bacteria. Individual FODMAPs can increase health-promoting bacteria, such as Akkermansia muciniphila and Bifidobacterium. It can mediate the host health-related effects through fermentation of short-chain carbohydrates to produce SCFAs and other metabolic pathways in the management and prevention of T2D.

Prediction and Assessment of Potential Microbial Substrate Utilisation Among More Recently Identified Health-Associated Gut Taxa

The contribution of the gut microbiota to health and disease is becoming ever more apparent in the last number of years, due to developments in DNA sequencing technology and more well-defined cultivation techniques. This has resulted in the identification of health-promoting bacteria. Until recently, prebiotics, non-digestible food substrates which are selectively utilised by beneficial bacteria, were employed with a view to increasing the growth of well-established health promoting bacteria, namely Lactobacillus and Bifidobacterium. However, other beneficial bacteria recently revealed may also be targeted to enhance their growth as they establish themselves as the next generation of health-promoting microbes. These include anaerobes such as Akkermansia muciniphila, Faecalibacterium prausnitziiand Eubacterium rectale. Identification of growth substrates/bioactives through the analysis of genome sequence data can aid in elucidating which substrates may best enhance the growth of these microbes which are often difficult to grow. The phenotypic microbial trait analyser, Traitar, can predict 67 phenotypes based on the genome sequence inputted. Some of these traits include substrates that could potentially be utilised by the bacteria. Another tool, CarveMe, which has been created with the aim of making metabolic modelling more user-friendly, was also used with the same genomes. A select number of substrates identified in both tools have been chosen to be evaluated in vitroin order to establish the accuracy of these predictive tools as well as giving an indication as to how these beneficial microbes can be modulated through dietary components.

Comparative Genomics and Pan-Genome Driven Prediction of a Reduced Genome of Akkermansia muciniphila.

Akkermanisia muciniphila imparts important health benefits and is considered a next-generation probiotic. It is imperative to understand the genomic diversity and metabolic potential of the species for safer applications as probiotics. As it resides with both health-promoting and pathogenic bacteria, understanding the evolutionary patterns are crucial, but this area remains largely unexplored. Moreover, pan-genome has previously been established based on only a limited number of strains and without careful strain selection. The pan-genomics have become very important for understanding species diversity and evolution. In the current study, a systematic approach was used to find a refined pan-genome profile of A. muciniphila by excluding too-diverse strains based on average nucleotide identity-based species demarcation. The strains were divided into four phylogroups using a variety of clustering techniques. Horizontal gene transfer and recombination patterns were also elucidated. Evolutionary patterns revealed that different phylogroups were expanding differently. Furthermore, a comparative evaluation of the metabolic potential of the pan-genome and its subsections was performed. Lastly, the study combines functional annotation, persistent genome, and essential genes to devise an approach to determine a minimal genome that can systematically remove unwanted genes, including virulent factors. The selection of one strain to be used as a chassis for the prediction of a reduced genome was very carefully performed by analyzing several genomic parameters, including the number of unique genes and the resistance and pathogenic potential of the strains. The strategy could be applied to other microbes, including human-associated microbiota, towards a common goal of predicting a minimal or a reduced genome.

The Neuroprotective Effects of Spray-Dried Porcine Plasma Supplementation Involve the Microbiota-Gut-Brain Axis.

Dietary supplementation with spray-dried porcine plasma (SDP) reduces the Alzheimer’s disease (AD) hallmarks in SAMP8 mice. Since gut microbiota can play a critical role in the AD progression, we have studied if the neuroprotective effects of SDP involve the microbiota−gut−brain axis. Experiments were performed on two-month-old SAMP8 mice fed a standard diet and on six-month-old SAMP8 mice fed a control diet or an 8% SDP supplemented diet for four months. Senescence impaired short- and long-term memory, reduced cortical brain-derived neurotrophic factor (BDNF) abundance, increased interleukin (Il)-1β, Il-6, and Toll-like receptor 2 (Tlr2) expression, and reduced transforming growth factor β (Tgf-β) expression and IL-10 concentration (all p < 0.05) and these effects were mitigated by SDP (all p < 0.05). Aging also increased pro-inflammatory cytokines in serum and colon (all p < 0.05). SDP attenuated both colonic and systemic inflammation in aged mice (all p < 0.05). SDP induced the proliferation of health-promoting bacteria, such as Lactobacillus and Pediococcus, while reducing the abundance of inflammation-associated bacteria, such as Johnsonella and Erysipelothrix (both q < 0.1). In conclusion, SDP has mucosal and systemic anti-inflammatory effects as well as neuroprotective properties in senescent mice; these effects are well correlated with SDP promotion of the abundance of probiotic species, which indicates that the gut–brain axis could be involved in the peripheral effects of SDP supplementation.

Investigation of the Ecological Link between Recurrent Microbial Human Gut Communities and Physical Activity.

ABSTRACTEmerging evidence has shown an association between the composition of intestinal microbial communities and host physical activity, suggesting that modifications of the gut microbiota composition may support training, performance, and post-exercise recovery of the host. Nevertheless, investigation of differences in the gut microbiota between athletes and individuals with reduced physical activity is still lacking. In this study, we performed a meta-analysis of 207 publicly available shotgun metagenomics sequencing data of fecal samples from athletes and healthy non-athletes. Accordingly, analysis of species-level fecal microbial profiles revealed three recurring compositional patterns, named HPC1 to 3, that characterize the host based on their commitment to physical activity. Interestingly, the gut microbiome of athletes showed a higher abundance of anti-inflammatory, health-promoting bacteria than that of non-athletic individuals. Moreover, the bacterial species profiled in the gut of professional athletes are short-fatty acid producers, which potentially improve energy production, and therefore sports performances. Intriguingly, microbial interaction network analyses suggested that exercise-induced microbiota adaptation involves the whole microbial community structure, resulting in a complex microbe-microbe interplay driven by positive relationships among the predicted butyrate-producing community members.IMPORTANCE Through metagenomic analyses, this work revealed that athletes have a gut-associated microbial community enriched in butyrate-producing species compared with non-athletes. This evidence can support the existence of a two-way association between the host’s lifestyle and the gut microbiota composition, with potential intriguing athletic performance outcomes.

Administration of probiotics to healthy volunteers: effects on reactivity of intestinal mucosa and systemic leukocytes

BackgroundOral administration of health-promoting bacteria is increasingly used in clinical practise. These bacteria have anti-inflammatory characteristics and modulate the immune system without major reported side effects. The mechanisms of action are not yet fully defined. Our aim was to study systemic effects of probiotics by measurements of leukocytes as well as local effects on rectal mucosal biopsies after adding a standardized inflammatory stimulus in vitro.MethodsFourteen healthy subjects were randomized to receive 1010 colony forming units/day orally of the probiotic strain Lactiplantibacillus plantarum 299 (Lp299), n = 7, or Bifidobacterium infantis CURE21 (CURE21), n = 7, for six weeks. Rectal biopsies were taken before and after ingestion of either probiotic strain product, for stimulation in vitro with tumour necrosis factor alpha (TNF-α) at 10 and 100 ng/ml respectively up to 8 h. Blood tests were sampled before and after treatment. Lactate dehydrogenase (LDH) confirmed viable tissue.ResultsComposition of the intestinal microbiota was not changed. Systemic leukocytes decreased after administration of CURE21 (P<0.05) and Lp299 (P<0.01). Levels of the pro-inflammatory cytokine IL-6 in rectal mucosa after stimulation with TNF-α were attenuated after ingestion of Lp299. No effect was seen with CURE21.ConclusionsAdministration of these probiotic strains to healthy humans show both a systemic and local reduction of inflammatory response by lowering leukocyte counts, and for Lp299 IL-6 levels in rectal mucosa. Probiotics may play an important role in the reduction of inflammatory responses expected after trauma during surgery or after pelvic irradiation.Trial registration Clinical Trials, registration number NCT01534572, retrospectively registered (http://www.clinicaltrials.gov).

COMPARISON OF DNA STANDARDS FOR REAL-TIME PCR-BASED QUANTIFICATION OF LACTOBACILLUS ACIDOPHILUS IN DAIRY PRODUCTS

Probiotic bacteria are an essential part of the healthy gut microbiota. Fermented foods as potential sources of health-promoting bacteria can regulate the intestinal microbial population. However, the exact quantification of these bacteria in such multiple-strain matrixes continues to remain elusive. In this study, we evaluated the reliability of genomic DNAs and cloned recombinant plasmids as standard controls for absolute real-time PCR assay. The associated standard curves were constructed and used for the quantification of Lactobacillus acidophilus probiotics. All stages from the design and construction of standards and related curves met the criteria for high-quality products. There were no significant differences between the two enumeration methods. However, plasmid-based standard curves resulted in a lower detection limit than the curves of genomic DNA standards. Our findings showed that the non-linearized recombinant plasmids had long-term stability at high concentrations during storage at -20 °C, which strongly depended on the purification methods. We propose that the recombinant plasmid standards can supersede the traditional genomic DNA standards for accurate quantification of probiotic bacteria.

Loss of Health Promoting Bacteria in the Gastrointestinal Microbiome of PICU Infants with Bronchiolitis: A Single-Center Feasibility Study.

The feasibility of gastrointestinal (GI) microbiome work in a pediatric intensive care unit (PICU) to determine the GI microbiota composition of infants as compared to control infants from the same hospital was investigated. In a single-site observational study at an urban quaternary care children’s hospital in Western Michigan, subjects less than 6 months of age, admitted to the PICU with severe respiratory syncytial virus (RSV) bronchiolitis, were compared to similarly aged control subjects undergoing procedural sedation in the outpatient department. GI microbiome samples were collected at admission (n = 20) and 72 h (n = 19) or at time of sedation (n = 10). GI bacteria were analyzed by sequencing the V4 region of the 16S rRNA gene. Alpha and beta diversity were calculated. Mechanical ventilation was required for the majority (n = 14) of study patients, and antibiotics were given at baseline (n = 8) and 72 h (n = 9). Control subjects’ bacterial communities contained more Porphyromonas, and Prevotella (p = 0.004) than those of PICU infants. The ratio of Prevotella to Bacteroides was greater in the control than the RSV infants (mean ± SD—1.27 ± 0.85 vs. 0.61 ± 0.75: p = 0.03). Bacterial communities of PICU infants were less diverse than those of controls with a loss of potentially protective populations.

Structure and fermentation characteristics of five polysaccharides sequentially extracted from sugar beet pulp by different methods

Pectic polysaccharides can serve as the best alternative for prebiotics, as they can be fermented in the gut by the microbiota. Many reports suggest that pectic polysaccharides' fermentation characteristics are superior to commercially available prebiotics as Inulin. However, these researches have focused on commercial pectin commonly extracted from apples or citrus, while pectins can exhibit complex and diverse structures. In this study, we extracted and characterized five structurally different polysaccharides from sugar beet pulp by water, 1,2-Cyclohexanediaminetetraacetic acid (CDTA), sodium carbonate, and sodium hydroxide, and then assessed their impacts on the human fecal microbiome. CDTA-soluble fraction and sodium carbonate-soluble fraction were identified as pectic polysaccharides, while water-soluble fraction and sodium hydroxide-soluble fractions were rich in the arabinose side chain. All polysaccharides were fermented more easily than inulin. Some neutral sugars were more easily fermented than acid sugar, and arabinose may be the first monosaccharide to be utilized by the microbiota, followed by glucose, fucose and galacturonic acid. After 48h of fermentation, some health-promoting bacteria like Faecalibacterium, Bifidobacterium, Lactobacillus, Blautia, and Prevotella increased, while some pathogenic bacteria like Fusobacterium, Sutterella, and Dorea decreased in all polysaccharides and Inulin. Hereby, through the study of the correlation between monosaccharide composition and microbiota, we showed that monosaccharide composition might be a critical structural feature linked to the polysaccharide-microbiota modulating effect. This could be helpful to have a criterion to choose the polysaccharides to better modulate the microbiota.

Food-grade olive oil Pickering emulsions stabilized by starch/β-cyclodextrin complex nanoparticles: Improved storage stability and regulatory effects on gut microbiota

The beneficial effects of olive oil consumption make it be one of the leading healthy edible oils worldwide. However, the water insolubility and oxidation of olive oil hinder its applications. In this study, food-grade oil-in-water olive oil Pickering emulsions (OOPEs) stabilized by hybrid starch/β-cyclodextrin nanoparticles (starch/β-CD NPs) was developed and characterized. The starch/β-CD NPs concentration and oil phase fraction had a significant influence on the droplet size, zeta potential and storage stability of emulsions. Confocal laser scanning microscopic observation revealed that the starch/β-CD NPs mainly located at the interface of oil droplets, forming a network structure to stabilize emulsions. Rheological analysis indicated the shear-thinning behavior and gel-like structure of starch/β-CD NPs stabilized OOPEs. Additionally, the obtained OOPEs remarkably improved the oxidative stability and storage stability by inhibiting the lipid oxidation compared to pure olive oil. Furthermore, animal experiments indicated that OOPEs modulated the gut microbiota in mice with an enhanced richness and diversity, resulting in an increased abundance of health-promoting bacteria. Notably, high-dosage OOPEs significantly decreased the ratio of phyla Firmicutes/Bacteroidetes. These findings could facilitate the development of olive oil Pickering emulsion with excellent stability and health effects on gut microbiota for applications in foods.

Formulation of Plant Nutrient with Synbiotic Enhancement

Oleochemical wastewater discharge from the industry into water sources is one of the main causes of water pollution. A proper treatment is required before the effluent is discharged to the environment. Since the oleochemical wastewater contains nutrients and probiotics that are good for plants, it could be used as a nutrient provider for the plants instead. Therefore, the formulation of synbiotic plant nutrients from this effluent is an effective way of using the oleochemical effluent. This study aimed to formulate the plant nutrients by using industrial wastewater, which contains the synbiotic enhancement and validating the significance of the formulated plant nutrients into three types of plants; Abelmoschus esculentus (Okra), Solanum Melongena (Brinjal), and Capsicum annuum (Chilli peppers). Synbiotic is a combination of both prebiotics and probiotics that benefit the host by stimulating the growth of a limited number of health-promoting bacteria. To formulate the plant nutrient, the wastewater was filtered using a cotton cloth before the pre-biotics solution was added. Sample A (filtered wastewater was mixed with Sample B (prebiotics solution) by different percentages, namely F1 (100%:0%), F2 (75%:25%), F3 (50%:50%), F3 (25%:75%), 0%:100% (Sample A to Sample B respectively) and lastly, 50%:50% (Sample C (unfiltered wastewater) to Sample B respectively). The height of the plant and the number of leaves are measured weekly for four months. From the data, it can be seen that F3 gave significant results for the okra plant, in which it gains the highest height of plant compared to the other two plants. On the other hand, F6 give the best results for both the brinjal and the chilli plant where their leaves grow the highest from the second until the fourth month of plant growth. Hence, this research gives an added value to the wastewater, whereas the wastewater is used as the synbiotic plant nutrient enhancer and work best for the plants.

Spectral binning of cervicovaginal fluid metabolites improves prediction of spontaneous preterm birth and Lactobacillus species dominance.

Lay summaryHealth-promoting bacteria (lactobacilli) exist in harmony with the vaginal environment. They are the predominant vaginal bacterial species during pregnancy. However, the possibility of infection and inappropriate immune response are linked with unprompted preterm delivery (PTD). Other invasive lactobacilli can alter the chemical environment of the vagina as they seek to promote their growth. This study measured the change in concentration of biochemical compounds and predominant bacterial species in vaginal fluid that are linked to PTD. The study recruited 300 healthy pregnant women who provided vaginal fluid samples during the second trimester. The women who harboured more of Lactobacillus jensenii over Lactobacillus crispatus (both reported as health-promoting bacteria) in their vaginal fluid had less lactate and glutamate and experienced more PTD. This suggests that lactate and glutamate levels in vaginal fluid may have clinical application in identifying which Lactobacillus species is most active. These chemical biomarkers could provide quick and accurate prediction of PTD risk in clinical settings.

Fermented Corn-Soybean Meal Mixed Feed Modulates Intestinal Morphology, Barrier Functions and Cecal Microbiota in Laying Hens.

Simple SummaryFermented feed has been of wide concern in livestock and poultry production because of its many advantages. In this study, the nutritional quality of the feed before and after fermentation was assessed, and four supplemental levels of fermented feed were used to replace unfermented feed to study the influence of fermented feed on the gut health of the laying hens during the laying peak period. The results suggest that fermented feed can improve the intestinal morphology and barrier functions of laying hens, possibly by altering the cecal microbiome.This study aimed to evaluate the effects of fermented corn–soybean meal mixed feed on intestinal barrier function and cecal microbiota in laying hens. A total of 360 Jingfen No.6 laying hens (22 wk-old) were assigned to 4 dietary treatments, which were offered basal diets (without antibiotics) containing 0, 4, 6 and 8% of fermented mixed feed respectively. The results showed that the pH value and anti-nutritional factor concentrations in fermented mixed feed were lower than those in unfermented feed (p < 0.05). Moreover, fermentation in the feed significantly increased the crude protein content (p < 0.05). Supplementation with fermented feed significantly reduced the crypt depth and increased the villi height:crypt depth ratio of duodenum and jejunum (p < 0.05). Meanwhile, fermented feed increased the secretory immunoglobulin A content and MUC2 mRNA expression of jejunum (p < 0.05). These beneficial effects were exhibited at the addition level ≥6% and microbial composition of caeca in the control, and so 6% fermented feed groups were analyzed. The structure of the gut microbiota was remarkably altered by additions, characterized by increased abundances of some health-promoting bacteria, such as Parasutterella, Butyricicoccus and Erysipelotrichaceae (p < 0.05). In summary, fermented mixed feed modulated cecal flora, subsequently contributing to improvements in intestinal morphology and barrier functions in laying hens.

Lactitol Supplementation Modulates Intestinal Microbiome in Liver Cirrhotic Patients.

Background: Cirrhosis is a common chronic liver disease characterized by irreversible diffuse liver damage. Intestinal microbiome dysbiosis and metabolite dysfunction contribute to the development of cirrhosis. Lactitol (4-β-D-galactopyranosyl-D-glucitol) was previously reported to promote the growth of intestinal Bifidobacteria. However, the effect of lactitol on the intestinal microbiome and fecal short-chain fatty acids (SCFAs) and bile acids (BAs) and the interactions among these factors in cirrhotic patients pre- and post-lactitol treatment remain poorly understood.Methods: Here, using shotgun metagenomics and targeted metabolomics methods.Results: we found that health-promoting lactic acid bacteria, including Bifidobacterium longum, B.pseudocatenulatum, and Lactobacillus salivarius, were increased after lactitol intervention, and significant decrease of pathogen Klebsiella pneumonia and associated antibiotic resistant genes /virulence factors. Functionally, pathways including Pseudomonas aeruginosa biofilm formation, endotoxin biosynthesis, and horizontal transfer of pathogenic genes were decreased in cirrhotic patients after 4-week lactitol intervention compared with before treatment.Conclusion: We identified lactitol-associated metagenomic changes, and provide insight into the understanding of the roles of lactitol in modulating gut microbiome in cirrhotic patients.

Neuropsychiatric Ramifications of COVID-19: Short-Chain Fatty Acid Deficiency and Disturbance of Microbiota-Gut-Brain Axis Signaling.

COVID-19-associated neuropsychiatric complications are soaring. There is an urgent need to understand the link between COVID-19 and neuropsychiatric disorders. To that end, this article addresses the premise that SARS-CoV-2 infection results in gut dysbiosis and an altered microbiota-gut-brain (MGB) axis that in turn contributes to the neuropsychiatric ramifications of COVID-19. Altered MGB axis activity has been implicated independently as a risk of neuropsychiatric disorders. A review of the changes in gut microbiota composition in individual psychiatric and neurological disorders and gut microbiota in COVID-19 patients revealed a shared “microbial signature” characterized by a lower microbial diversity and richness and a decrease in health-promoting anti-inflammatory commensal bacteria accompanied by an increase in opportunistic proinflammatory pathogens. Notably, there was a decrease in short-chain fatty acid (SCFA) producing bacteria. SCFAs are key bioactive microbial metabolites with anti-inflammatory functions and have been recognized as a critical signaling pathway in the MGB axis. SCFA deficiency is associated with brain inflammation, considered a cardinal feature of neuropsychiatric disorders. The link between SARS-CoV-2 infection, gut dysbiosis, and altered MGB axis is further supported by COVID-19-associated gastrointestinal symptoms, a high number of SARS-CoV-2 receptors, angiotensin-cleaving enzyme-2 (ACE-2) in the gut, and viral presence in the fecal matter. The binding of SARS-CoV-2 to the receptor results in ACE-2 deficiency that leads to decreased transport of vital dietary components, gut dysbiosis, proinflammatory gut status, increased permeability of the gut-blood barrier (GBB), and systemic inflammation. More clinical research is needed to substantiate further the linkages described above and evaluate the potential significance of gut microbiota as a diagnostic tool. Meanwhile, it is prudent to propose changes in dietary recommendations in favor of a high fiber diet or supplementation with SCFAs or probiotics to prevent or alleviate the neuropsychiatric ramifications of COVID-19.

COMPARISON OF DNA STANDARDS FOR REAL-TIME PCR-BASED QUANTIFICATION OF LACTOBACILLUS ACIDOPHILUS IN DAIRY PRODUCTS: DNA standards for quantification of probiotics

Probiotic bacteria are an essential part of the healthy gut microbiota. Fermented foods as potential sources of health-promoting bacteria can regulate the intestinal microbial population. However, the exact quantification of these bacteria in such multiple-strain matrixes continues to remain elusive. In this study, we evaluated the reliability of genomic DNAs and cloned recombinant plasmids as standard controls for absolute real-time PCR assay. The associated standard curves were constructed and used for the quantification of Lactobacillus acidophilus probiotics. All stages from the design and construction of standards and related curves met the criteria for high-quality products. There were no significant differences between the two enumeration methods. However, plasmid-based standard curves resulted in a lower detection limit than the curves of genomic DNA standards. Our findings showed that the non-linearized recombinant plasmids had long-term stability at high concentrations during storage at -20 °C, which strongly depended on the purification methods. We propose that the recombinant plasmid standards can supersede the traditional genomic DNA standards for accurate quantification of probiotic bacteria.

Lipocalin 2 Deficiency Restrains Aging-Related Reshaping of Gut Microbiota Structure and Metabolism.

Gut microbiota modulate age-associated changes in metabolism, innate immune responses, and cognitive function. However, the involvement of host factors in the regulation of age-dependent gut microbial structure and intestinal inflammation is largely unknown. Lipocalin 2 (Lcn2) has previously been identified as an adipocytokine and characterized as an important regulator of diet-induced obesity and inflammation. Previous studies have shown that Lcn2 plays a role in high fat diet-induced reshaping of gut microbiota and intestinal inflammation. However, the role of Lcn2 in the regulation of aging-related reshaping of gut microbiota is unclear. Herein, we demonstrate that fecal levels of Lcn2 are reduced during aging. Age reshaped gut microbiota composition in wild-type (WT) mice. Interestingly, Lcn2 deficiency diminished this effect of aging in Lcn2 knockout (LKO) mice, leading to decreased bacterial diversity and increased Firmicutes to Bacteroidetes (F to B) ratio. Specifically, we identified 16 bacteria at the family level that were differentially abundant between WT and LKO mice at old age. Several health-promoting bacteria, including SCFA-producing bacteria, were significantly less prevalent in old LKO mice compared to WT mice, indicating that Lcn2 deficiency shifts the aging-related gut microbial community towards an unhealthy population and lowers microbial butyrate production. Our results provide a line of evidence that Lcn2 plays a role in the control of aging-related reshaping of gut microbiota composition and metabolites.

The Pregnancy and EARly Life study (PEARL) - a longitudinal study to understand how gut microbes contribute to maintaining health during pregnancy and early life

BackgroundThe early life period represents the first step in establishing a beneficial microbial ecosystem, which in turn affects both short and longer-term health. Changes during pregnancy influence the neonatal microbiome; through transmission of maternal microbes during childbirth, and beyond, through nutritional programming. However, in-depth exploration of longitudinal maternal-infant cohorts, with sampling of multiple body sites, complemented by clinical and nutritional metadata, and use of cutting-edge experimental systems are limited.The PEARL study will increase our knowledge of; how microbes (including viruses/phages, bacteria, fungi and archaea) change in composition and functional capacity during pregnancy; transmission pathways from mother to infant; the impact of various factors on microbial communities across pregnancy and early life (e.g. diet), and how these microbes interact with other microbes and modulate host processes, including links to disease onset.MethodsPEARL is a longitudinal observational prospective study of 250 pregnant women and their newborns, with stool and blood samples, questionnaires and routine clinical data collected during pregnancy, labour, birth and up to 24 months post birth.Metagenomic sequencing of samples will be used to define microbiome profiles, and allow for genus, species and strain-level taxonomic identification and corresponding functional analysis. A subset of samples will be analysed for host (immune/metabolite) molecules to identify factors that alter the host gut environment. Culturing will be used to identify new strains of health-promoting bacteria, and potential pathogens. Various in vitro and in vivo experiments will probe underlying mechanisms governing microbe-microbe and microbe-host interactions.DiscussionLongitudinal studies, like PEARL, are critical if we are to define biomarkers, determine mechanisms underlying microbiome profiles in health and disease, and develop new diet- and microbe-based therapies to be tested in future studies and clinical trials.Trial registrationThis study is registered in the ClinicalTrials.gov Database with ID: NCT03916874.