Microbiome Function Research Articles

Antibacterial periodontal ligament stem cells enhance periodontal regeneration and regulate the oral microbiome

BackgroundThe transplantation of periodontal ligament stem cells (PDLSCs) has been shown to enhance periodontal regeneration in animal models and clinical trials. However, it is not known whether PDLSCs are antibacterial and whether this affects oral microbiota and periodontal regeneration.MethodsWe isolated human PDLSCs from periodontal ligament of extracted teeth. Rats’ periodontal fenestration defects were prepared, and treated with PDLSC injections (Cell group), using saline injections (Saline group) as the control. The oral microbiota was explored by 16 S rDNA sequencing and compared with that before surgery (PRE group). The antibacterial property of PDLSCs and its underlying mechanism were tested in vitro.ResultsMicrobiome analyses reveal a decreased biodiversity, a changed community structure, and downregulated community functions of the oral microbiome in the Saline group. PDLSCs injections enhance periodontal regeneration, reverse the decrease in diversity, and increase the abundance of non-pathogenic bacterial Bifidobacterium sp. and Lactobacillus sp., making the oral microbiome similar to that of the PRE group. In vitro, PDLSCs inhibit the growth of Staphylococcus aureus, Escherichia coli, and Fusobacterium nucleatum. The main mechanism of action is postulated to involve production of the cationic antimicrobial peptide LL-37.ConclusionsOur findings reveal that PDLSC injections enhance periodontal regeneration and regulate the oral microbiome to foster an oral cavity microenvironment conducive to symbiotic microbiota associated with health.

Interactions between microplastics and organic contaminants: the microbial mechanisms for priming effects of organic compounds on microplastic biodegradation

The co-presence of plastics and other organic contaminants is pervasive in various ecosystems, particularly in areas with intensive anthropogenic activities. Their interactions inevitably impact the composition and functions of the plastisphere microbiome, which in turn determines the trajectory of these contaminants. Antibiotics are a group of organic contaminants that warrant particular attention due to their wide presence in environments and significant potential to disseminate antibiotic resistance genes (ARGs) within the plastisphere. Therefore, this study investigated the impacts of sulfadiazine (SDZ), a prevalent environmental antibiotic, on the composition and function of the plastisphere microbial community inhabiting micro-polyethylene (mPE), one of the most common microplastic contaminants. Our findings indicated that the presence of SDZ increased the overall plastisphere microbial abundance and enriched populations that are capable of degrading both SDZ and mPE. The abundance of Aquabacterium, a dominant plastisphere population that is capable of degrading both SDZ and mPE, increased over the course of SDZ exposure, while another abundant mPE-degrading population, Ketobacter, remained stable. Accordingly, the removal of SDZ was enhanced in the presence of mPE. Moreover, the results further revealed that not only SDZ but also other labile organic contaminants (e.g., aniline and hexane) could accelerate mPE biodegradation through a priming effect. This investigation underscores the complex dynamics among microplastics, organic contaminants, and the plastisphere microbiome, offering insights into the environmental fate of plastic and antibiotic pollutants.

Altered oral microbiota of drug-resistant organism carriers exhibit impaired gram-negative pathogen inhibition.

The oral microbiome has been understudied as a reservoir for clinical pathogens, including drug-resistant strains. Understanding how alterations in microbiome functioning render this site vulnerable to colonization is essential, as multidrug-resistant organisms (MDRO) carriage is a major risk factor for developing serious infections. To advance our knowledge of oral MDRO carriage and protection against pathogen colonization conferred by native microbiota, we examined microbiomes from individuals colonized by MDROs (n=33) and non-colonized age-matched controls (n=30). Shotgun metagenomic analyses of oral swabs from study participants revealed significant differences in microbial communities with depletion of Streptococcus spp. among those colonized by multidrug-resistant gram-negative bacilli (RGNB), compared to non-carriers. We utilized metagenomic sequencing to characterize the oral resistome and find antimicrobial resistance genes are present in higher abundance among RNGB carriers versus non-carriers. High-throughput co-culture screening revealed oral bacteria isolated from MDRO non-carriers demonstrate greater inhibition of gram-negative pathogens, compared to isolates from carriers. Moreover, biosynthetic gene clusters from streptococci are found in higher abundance from non-carrier microbiomes, compared to RGNB carrier microbiomes. Bioactivity-guided fractionation of extracts from Streptococcus isolate SID2657 demonstrated evidence of strong E. coli and A. baumannii inhibition in a murine model of infection. Together, this provides evidence that oral microbiota shape this dynamic microbial community and may serve as an untapped source for much-needed antimicrobial small-molecules.

Species-specific impact of protists in controlling litter decomposition

Protists affect soil microbiome composition and functioning, potentially increasing litter decomposition and plant growth. Yet, the role of different protist species, individually or in combinations, in regulating microbial-mediated litter decomposition remains unknown, as well as if these interactions feedback to plant growth. Using a full-factorial design of three protist species combinations with bacterial and fungal communities, we found that only one protist species reduced litter decomposition by 19%, with other species and combinations not affecting litter decomposition. Despite a positive correlation between plant growth and litter decomposition, we did not observe protist-induced changes in plant growth. Overall, our results highlight that protists affect litter decomposition in a species-specific manner, including reducing litter decomposition.

Fecal microbiome and functional prediction profiles of horses with and without crib-biting behavior: A comparative study

Crib-biting is a stereotyped oral behavior with poorly understood etiology and pathophysiology. The relationship between the gut microbiome and brain function has been described in behavioral disorders such as schizophrenia, depression and anxiety in humans. In horses, studies of behavioral problems and the microbiome are very limited. This study aimed to characterize the fecal microbiome and the predicted functional profile of horses with and without aerophagia. Fecal samples were collected from 12 Colombian Creole Horses of both sexes, divided into two groups: group 1, composed of six horses with crib-biting (3 females and 3 males), average body weight of 330 ± 10 kg, age of 7.0 ± 1.2 years and body condition score (BCS) of 5/9 ± 1 and group 2, consisting of six horses without crib-biting (3 females and 3 males), average body weight of 335 ± 5 kg, age 6.5 ± 1 years and BCS of 6/9 ± 1. From each horse in both groups fecal total DNA was obtained and 16S ribosomal RNA gene amplicons were sequenced to characterize the bacterial community structure. Community structure and differential abundance analyses revealed significant differences between the two conditions (p < 0.05). Specifically, the fecal microbiota at the family level in crib-biting horses, showing a decrease in Bacteroidales and an increase in Bacillota and Clostridia, differed from that of healthy horses without crib-biting, consistent with findings from previous studies. Furthermore, metagenome prediction suggests metabolic profile changes in bacterial communities between both conditions in horses. Further studies are required to validate the role of the microbiota-gut-brain axis in the etiology of crib-biting and other abnormal and stereotyped behaviors.

Genomic profiling of Antarctic geothermal microbiomes using long-read, Hi-C, and single-cell techniques

Geothermal features in Antarctica provide favorable conditions for diverse microorganisms, yet their genomic diversity remains poorly understood. Here, we present an integrated dataset comprising PacBio HiFi and Hi-C metagenomic sequencing, along with single-cell amplified genomes (SAGs) from two high-altitude geothermal sites, Mount Melbourne and Mount Rittmann, in Antarctica. The long-read HiFi sequencing, coupled with Hi-C, enhances the understanding of microbiome diversity and functionality in this unique ecosystem by providing more complete and accurate genomic information. SAGs complement this by recovering rare microbial taxa and offering a strain-resolved perspective. This dataset aims to deepen our understanding of microbial evolution and ecology in Antarctic geothermal environments, and facilitate cross-comparison with other geothermal environments globally.

Intestinal microbiota and metabolically associated steatotic liver disease: current understanding of the problem. Review

Cross‑interaction of microbes, microbial products, and the intestinal barrier are components of the so‑called «intestine‑liver axis», as the liver and intestines have a close two‑way relationship. In patients with metabolically associated steatotic liver disease (MASLD), significant characteristic changes in the intestinal microbiome are observed, in particular, the growth of gram‑negative bacteria, which contributes to the formation of a pro‑inflammatory status (primarily due to endotocins) and disruption of metabolic processes, while an increase in Bacteroides and Ruminococcus and a decrease in Prevotella are associated with severe stages of liver fibrosis. Intestinal microbiota modulates the pool of bile acids thereby affecting metabolic homeostasis and pro‑inflammatory processes. Dysbiosis associated with MASLD is characterized by an excess of bacteria — producers of secondary bile acids, which are one of the factors in the progression of metabolically associated steatohepatitis. In addition, dysbiosis leads to increased production of short‑chain fatty acids, which promotes gluconeogenesis, synthesis and accumulation of toxic lipids in the liver and, accordingly, the development and progression of MASLD. But liver function disorders connected with dysbiosis are associated not only with intestinal bacteria, but also with fungi and viruses. According to the results of recent studies, MASLD is associated with a significant diversity of the mycobiome and has certain differences in the progression of the disease depending on the degree of liver inflammation and the stage of fibrosis. Chronic hyperproduction of endogenous ethanol (Klebsiella pneumoniae, Escherichia, Candida, etc.) is an important factor in the pathogenesis of MASLD, as it disrupts glucose and lipid metabolism, contributing to the formation of liver steatosis and steatohepatitis. Ultrastructural and functional changes of mitochondria are recognized determinants in the pathogenesis of MASLD. Mitochondria and intestinal microbiota have a bidirectional relationship: microbiota supplies metabolites for mitochondrial metabolism and redox homeostasis, and the development of dysbiosis contributes to oxidative stress and proinflammatory status — key factors in the development of metabolically associated steatohepatitis. Mitochondria can also modulate intestinal microflora by affecting the permeability of the intestinal barrier. The data presented in the article expand our knowledge about the interaction of the liver and the intestine and inspire the development of new promising therapeutic approaches to the treatment of MASLD, which involve a synergistic effect on the intestinal microbiota, microbiome, virome, and mitochondrial function.

Effects of antibiotic and disinfectant exposure on the mouse gut microbiome and immune function.

Disinfectants are extensively employed across various sectors, such as the food sector. Disinfectants are widely used in various sectors, including the food processing industry, animal husbandry, households, and pharmaceuticals. Their extensive application risks environmental contamination, impacting water and soil quality. However, the effect of disinfectant exposure on the gut microbiome and the immune function of animals remains a significant, unresolved issue with profound public health implications. This highlights the need for increased scrutiny and more regulated use of disinfectants to mitigate unintended consequences on gut health and maintain immune system integrity.

Optimal Irrigation and Fertilization Enhanced Tomato Yield and Water and Nitrogen Productivities by Increasing Rhizosphere Microbial Nitrogen Fixation

Irrigation and nitrogen application rates have significant effects on greenhouse tomato yields, as well as water and nitrogen use efficiencies, but little is known regarding how these rates affect plant–microbiome interactions and how the associated changes might impact tomato yields. In this greenhouse study conducted over two years, the effects of three irrigation levels (moderate deficit with 65–75% water holding capacity threshold, slight deficit with 75–85%, and sufficient irrigation with 85–95%) and four nitrogen application levels (60, 120, 240, and 360 kg ha−1) on tomato growth, yield, water and nitrogen productivities, and rhizosphere microbial diversities and functions were investigated. The results demonstrated that the highest tomato leaf area, dry biomass, yield, and water and nitrogen productivities were obtained under the treatment with sufficient irrigation. With increasing nitrogen application, the tomato leaf area, dry biomass, yield, and water and nitrogen productivities showed a trend of first increasing and then decreasing. Overall, the treatment (N2W3) with sufficient irrigation and 240 kg ha−1 N was associated with the highest tomato growth, yield, and water and nitrogen productivities. Moreover, optimal irrigation and nitrogen application obviously altered the structures of rhizosphere bacterial and fungal communities, particularly recruiting microbiota conferring benefits to tomato growth and nitrogen fixation—namely, Lysobacter and Bradyrhizobium. Ultimately, optimal irrigation and nitrogen application significantly increased the relative abundances of functions related to carbon, sulfur, and nitrogen metabolism, especially nitrogen fixation. In summary, optimal irrigation and fertilization enhanced tomato yield, as well as water and nitrogen productivities by increasing the nitrogen fixation functions of the rhizosphere microbiome. Our results provide significant implications for tomato cultivation in greenhouses, in terms of optimized irrigation and fertilization.

Genomics and synthetic community experiments uncover the key metabolic roles of acetic acid bacteria in sourdough starter microbiomes.

This study is a comprehensive genomic and ecological survey of acetic acid bacteria (AAB) isolated from sourdough starters. By combining comparative genomics with manipulative experiments using synthetic microbiomes, we demonstrate that even strains with >97% average nucleotide identity can shift important microbiome functions, underscoring the importance of species and strain diversity in microbial systems. We also demonstrate the utility of sourdough starters as a model system to understand the consequences of genomic diversity at the strain and species level on multispecies communities. These results are also relevant to industrial and home-bakers as we uncover the importance of AAB in shaping properties of sourdough starters that have direct impacts on sensory notes and the quality of sourdough bread.

Exploring the microbiome: New horizons for emerging therapeutics

The document discusses the topic of microbiomes, specifically focusing on the human microbiome and its various aspects. It starts by explaining the concept of human microbiota, which refers to the collection of microorganisms that live in and interact with the human body. The document highlights the importance of these microbial ecosystems in maintaining overall health and wellbeing. The composition and function of the gut microbiome undergo significant changes during the first year of life, especially with the introduction of solid foods. The document discusses the different bacterial phyla that dominate the gut microbiome in neonatal infants and adults. It also mentions the role of the human gut microbiome in various health conditions such as liver diseases, diabetes, inflammatory bowel disease, autoimmune diseases, colon cancer, and central nervous system disorders. The document highlights the different sequencing techniques used in microbiome research, such as ITS sequencing, PCR amplicon-based sequencing, and shotgun metagenomic sequencing. It also discusses the concept of the halobiont and holo genome in relation to the microbiome. The document emphasizes the importance of studying the microbiome in the context of ecosystem health and discusses the impact of human populations on environmental microorganisms. Furthermore, the document covers the microbial barrier in the human gut, the role of the gut microbiota in various metabolic processes, and the application of gut microbiomes in bioengineering, both in humans and other organisms. Lastly, it discusses the importance of dietary interventions, prebiotics, and the role of various diets in influencing the composition of the gut microbiome and treating gastrointestinal disorders. Overall, the document provides a comprehensive overview of the human microbiome and its significance in health and disease, as well as its potential applications in bioengineering and dietary interventions.

PSLBI-20 Dynamic response of piglets fed different sources and levels of fiber during an enterotoxigenic Escherichia coli (ETEC) challenge in the post-weaning transition

Abstract Dietary fiber can stimulate the growth of volatile fatty acid-producing bacteria, hence promoting gut health. A stimbiotic can accelerate the settlement of a fiber-fermenting microbiome after weaning. The present study aimed to investigate how different fiber types and a stimbiotic can support microbiome function and resilience of piglets facing an F18 ETEC challenge. Newly weaned piglets (n = 216) were blocked by body weight (BW) and randomly assigned to 1 of 4 dietary treatments (n = 9), including a corn-soy and wheat middlings control diet (CTL), high fiber diet (HF), CTL plus 0.01% stimbiotic (CS; Signis; AB Vista, UK), and HF plus 0.01% stimbiotic (HFS). The HF diets included sugar beet pulp at 5.0%, 3.8%, 2.5% and soy hulls at 4.0%, 3.0% and 2.0% for phases 1 (d 0 to 9), 2 (d 0 to 16), and 3 (d 16 to 22), respectively. A standard diet was fed during phase 4 (d 22 to 41). On d 5 post-weaning, all pigs were orally inoculated with 10 mL of F18 ETEC (108 CFU/mL). Twelve piglets were selected from different pens, and a fecal sample was collected on d 5 before challenge (0 d post-inoculation; dpi), d 12 (dpi 7) and d 29 (dpi 24) for analysis of microbial populations by qPCR and fecal calprotectin. Statistical analyses consisted of a multivariate analysis by age, with fiber, stimbiotic, and their interaction as fixed effects. There was no main effect of fiber or stimbiotic on final BW, and d 0 to 40 average daily gain (ADG) or gain to feed (G:F; P &amp;gt; 0.10). Overall, pigs fed CS had a greater intake than HFS (P &amp;lt; 0.05) with CTL and HF intermediate. Piglets fed CS and HF tended to have greater ADG from d 0 to 22 compared with pigs fed CTL (P &amp;lt; 0.10). Piglets fed CS tended to have heavier d 22 BW than CTL (P &amp;lt; 0.10), with HF and HFS intermediate. On dpi 0, butyrate-producing bacteria Lachnospiraceae and Ruminococcaceae were increased in piglets fed a stimbiotic (P &amp;lt; 0.05). On dpi 0 and 7, piglets fed HF had increased abundance of Lachnospiraceae (P &amp;lt; 0.05), whereas no difference was observed on dpi 24 (P &amp;gt; 0.10). Total E. coli did not vary between groups (P &amp;gt; 0.10). On dpi 0, calprotectin concentration was similar between treatments (averaged 25 ng/g feces; P &amp;gt; 0.10) Calprotectin was less in piglets fed a stimbiotic, at 7 vs 22 ng/g feces on dpi 7, and 8 vs 19 ng/g feces on dpi 24 in the stimbiotic and no stimbiotic group, respectively (P &amp;lt; 0.05). There was no fiber or fiber × stimbiotic interaction for calprotectin (P &amp;gt; 0.10). These results demonstrate that feeding high fiber may accelerate the settlement of the piglet microbiome profile as early as 5 d post-weaning. Feeding a stimbiotic may support the resilience of piglets facing an F18 ETEC challenge by promoting the growth of butyrate-producing bacteria, which alleviates the gastrointestinal tract inflammation response and ultimately boost growth performance.

Metformin modulates microbiota and improves blood pressure and cardiac remodeling in a rat model of hypertension.

Metformin has been attributed to cardiovascular protection even in the absence of diabetes. Recent observations suggest that metformin influences the gut microbiome. We aimed to investigate the influence of metformin on the gut microbiota and hypertensive target organ damage in hypertensive rats. Male double transgenic rats overexpressing the human renin and angiotensinogen genes (dTGR), a model of angiotensin II-dependent hypertension, were treated with metformin (300 mg/kg/day) or vehicle from 4 to 7 weeks of age. We assessed gut microbiome composition and function using shotgun metagenomic sequencing and measured blood pressure via radiotelemetry. Cardiac and renal organ damage and inflammation were evaluated by echocardiography, histology, and flow cytometry. Metformin treatment increased the production of short-chain fatty acids (SCFA) acetate and propionate in feces without altering microbial composition and diversity. It significantly reduced systolic and diastolic blood pressure and improved cardiac function, as measured by end-diastolic volume, E/A, and stroke volume despite increased cardiac hypertrophy. Metformin reduced cardiac inflammation by lowering macrophage infiltration and shifting macrophage subpopulations towards a less inflammatory phenotype. The observed improvements in blood pressure, cardiac function, and inflammation correlated with fecal SCFA levels in dTGR. Invitro, acetate and propionate altered M1-like gene expression in macrophages, reinforcing anti-inflammatory effects. Metformin did not affect hypertensive renal damage or microvascular structure. Metformin modulated the gut microbiome, increased SCFA production, and ameliorated blood pressure and cardiac remodeling in dTGR. Our findings confirm the protective effects of metformin in the absence of diabetes, highlighting SCFA as a potential mediators.

Insights into Gut Dysbiosis: Inflammatory Diseases, Obesity, and Restoration Approaches.

The gut microbiota is one of the most critical factors in human health. It involves numerous physiological processes impacting host health, mainly via immune system modulation. A balanced microbiome contributes to the gut's barrier function, preventing the invasion of pathogens and maintaining the integrity of the gut lining. Dysbiosis, or an imbalance in the gut microbiome's composition and function, disrupts essential processes and contributes to various diseases. This narrative review summarizes key findings related to the gut microbiota in modern multifactorial inflammatory conditions such as ulcerative colitis or Crohn's disease. It addresses the challenges posed by antibiotic-driven dysbiosis, particularly in the context of C. difficile infections, and the development of novel therapies like fecal microbiota transplantation and biotherapeutic drugs to combat these infections. An emphasis is given to restoration of the healthy gut microbiome through dietary interventions, probiotics, prebiotics, and novel approaches for managing gut-related diseases.

Probing the functional significance of wild animal microbiomes using omics data

Abstract Host‐associated microbiomes are thought to play a key role in host physiology and fitness, but this conclusion mainly derives from systems biased towards animal models and humans. While many studies on non‐model and wild animals have characterised the taxonomic diversity of their microbiomes, few have investigated the functional potential of these microbial communities. Functional ‘omics’ approaches, such as metagenomics, metatranscriptomics and metabolomics, represent promising techniques to probe the significance of host‐associated microbiomes in the wild. In this review, we propose to (1) briefly define the main available functional omics tools along with their strengths and limitations, (2) summarise the key advances enabled by omics tools to understand microbiome function in human and animal models, (3) showcase examples of how these methods have already brought invaluable insights into wild host microbiomes and (4) provide guidelines on how to implement these tools to address outstanding questions in the field of wild animal microbiomes. To conclude, we suggest that, building on knowledge derived from cheaper, more traditional approaches (e.g. 16S metabarcoding and qPCR), functional omics tools represent a promising approach to test hypotheses regarding the ecological and evolutionary significance of the resident microbiota in wild animals. Read the free Plain Language Summary for this article on the Journal blog.

Disentangling abiotic and biotic effects of treated wastewater on stream biofilm resistomes enables the discovery of a new planctomycete beta-lactamase

BackgroundEnvironmental reservoirs of antibiotic resistance pose a threat to human and animal health. Aquatic biofilms impacted by wastewater effluent (WW) are known environmental reservoirs for antibiotic resistance; however, the relative importance of biotic factors and abiotic factors from WW on the abundance of antibiotic resistance genes (ARGs) within aquatic biofilms remains unclear. Additionally, experimental evidence is limited within complex aquatic microbial communities as to whether genes bearing low sequence similarity to validated reference ARGs are functional as ARGs.ResultsTo disentangle the effects of abiotic and biotic factors on ARG abundances, natural biofilms were previously grown in flume systems with different proportions of stream water and either ultrafiltered or non-ultrafiltered WW. In this study, we conducted deep shotgun metagenomic sequencing of 75 biofilm, stream, and WW samples from these flume systems and compared the taxonomic and functional microbiome and resistome composition. Statistical analysis revealed an alignment of the resistome and microbiome composition and a significant association with experimental treatment. Several ARG classes exhibited an increase in normalized metagenomic abundances in biofilms grown with increasing percentages of non-ultrafiltered WW. In contrast, sulfonamide and extended-spectrum beta-lactamase ARGs showed greater abundances in biofilms grown in ultrafiltered WW compared to non-ultrafiltered WW. Overall, our results pointed toward the dominance of biotic factors over abiotic factors in determining ARG abundances in WW-impacted stream biofilms and suggested gene family-specific mechanisms for ARGs that exhibited divergent abundance patterns. To investigate one of these specific ARG families experimentally, we biochemically characterized a new beta-lactamase from the Planctomycetota (Phycisphaeraceae). This beta-lactamase displayed activity in the cleavage of cephalosporin analog despite sharing a low sequence identity with known ARGs.ConclusionsThis discovery of a functional planctomycete beta-lactamase ARG is noteworthy, not only because it was the first beta-lactamase to be biochemically characterized from this phylum, but also because it was not detected by standard homology-based ARG tools. In summary, this study conducted a metagenomic analysis of the relative importance of biotic and abiotic factors in the context of WW discharge and their impact on both known and new ARGs in aquatic biofilms.DkJa1T-YWptaXXeH_hsDtBVideo

Integrated analysis of facial microbiome and skin physio-optical properties unveils cutotype-dependent aging effects

BackgroundOur facial skin hosts millions of microorganisms, primarily bacteria, crucial for skin health by maintaining the physical barrier, modulating immune response, and metabolizing bioactive materials. Aging significantly influences the composition and function of the facial microbiome, impacting skin immunity, hydration, and inflammation, highlighting potential avenues for interventions targeting aging-related facial microbes amidst changes in skin physiological properties.ResultsWe conducted a multi-center and deep sequencing survey to investigate the intricate interplay of aging, skin physio-optical conditions, and facial microbiome. Leveraging a newly-generated dataset of 2737 species-level metagenome-assembled genomes (MAGs), our integrative analysis highlighted aging as the primary driver, influencing both facial microbiome composition and key skin characteristics, including moisture, sebum production, gloss, pH, elasticity, and sensitivity. Further mediation analysis revealed that skin characteristics significantly impacted the microbiome, mostly as a mediator of aging. Utilizing this dataset, we uncovered two consistent cutotypes across sampling cities and identified aging-related microbial MAGs. Additionally, a Facial Aging Index (FAI) was formulated based on the microbiome, uncovering the cutotype-dependent effects of unhealthy lifestyles on skin aging. Finally, we distinguished aging related microbial pathways influenced by lifestyles with cutotype-dependent effect.ConclusionsTogether, our findings emphasize aging’s central role in facial microbiome dynamics, and support personalized skin microbiome interventions by targeting lifestyle, skin properties, and aging-related microbial factors.8-x6JkQezK-S195ofXGtyGVideo

Gut Microbiome Compositional and Functional Features Associate with Alzheimer's Disease Pathology.

The gut microbiome is a potentially modifiable factor in Alzheimer's disease (AD); however, understanding of its composition and function regarding AD pathology is limited. Shallow-shotgun metagenomic data was used to analyze fecal microbiome from participants enrolled in the Wisconsin Microbiome in Alzheimer's Risk Study, leveraging clinical data and cerebrospinal fluid (CSF) biomarkers. Differential abundance and ordinary least squares regression analyses were performed to find differentially abundant gut microbiome features and their associations with CSF biomarkers of AD and related pathologies. Gut microbiome composition and function differed between people with AD and cognitively unimpaired individuals. The compositional difference was replicated in an independent cohort. Differentially abundant gut microbiome features were associated with CSF biomarkers of AD and related pathologies. These findings enhance our understanding of alterations in gut microbial composition and function in AD, and suggest that gut microbes and their pathways are linked to AD pathology.

Gut Microbiome Changes among Undernutrition and Stunting Infants and Children under 2 Years: A Scoping Review

Background Undernutrition and stunting are significant public health concerns globally, particularly in low- and middle-income countries. Nutritional intervention is the cornerstone of the management and prevention of these conditions. However, the gut microbiome has recently emerged as an essential modulator of the effects of nutritional interventions in undernutrition and stunting. This scoping review aims to examine the impact of nutrition intake (including if there is any intervention) over time on gut microbiome changes in infants and children under the age of 2 who experience undernutrition and stunting. Methods A literature search was conducted in PubMed and Cochrane Library, including studies from 2013 to 2023, using terms related to malnutrition, stunting, failure to thrive, and gut microbiome. Inclusion criteria were applied to select eligible studies for review. Five studies were chosen to be included in this review. Results The findings indicate that nutrition intake over time, including dietary supplementation and prebiotics, can influence the gut microbiome composition, diversity, and functionality in undernutrition and stunting infants and children. These may promote the growth of beneficial bacteria while reducing the abundance of harmful pathogens. Moreover, improvements in nutritional status, growth parameters, and immune function were observed in association with positive changes in the gut microbiota. Conclusion Nutrition intake can positively modulate the gut microbiome in undernutrition and stunting infants by supporting the growth of beneficial gut bacteria such as Actinobacteria, Bacteroides, Streptococcus, Bifidobacterium, Prevotella sp, and other bacterial taxa that vary with age, ultimately contributing to enhanced growth and development outcomes. Further studies are needed to better understand the mechanisms underlying these effects and to develop targeted nutritional interventions that optimize the gut microbiome in undernutrition and stunting infants and children under 2 years.

Effects of a xylitol-casein complex on insulin resistance and gut microbiota composition in high-fat-diet + streptozotocin-induced type 2 diabetes mellitus mice

This study investigated the effects of a xylitol-casein non-covalent complex (XC) on parameters related to type 2 diabetes mellitus (T2DM), in addition to related changes in gut microbiome composition and functions. High-fat-diet (HFD) + streptozotocin (STZ)-induced T2DM mice were treated with xylitol (XY), casein (CN), and XC, after which fecal samples were collected for gut microbiota composition and diversity analyses based on 16S rRNA high-throughput sequencing and multivariate statistics. XC decreased body weight and improved glucose tolerance, insulin sensitivity, pancreas impairment, blood lipid levels, and liver function in T2DM mice compared to XY- and CN-treated mice. Furthermore, XC modulated the α-diversity, β-diversity and gut microbiota composition. Based on Spearman’s correlation analysis, the relative abundances of Alistipes, Bacteroides, and Faecalibaculum were positively correlated and those of Akkermansia, Lactobacillus, Bifidobacterium, and Turicibacter were negatively correlated with the phenotypes related to the improvement of T2DM. In conclusion, we found that XC alleviated insulin resistance by restoring the gut microbiota of T2DM mice. Our results provide strong evidence for the beneficial effects of XC on T2DM and motivation for further investigation in animal models and, eventually, human trials.