Gut microbiome of the Hadza hunter-gatherers

Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience

Anisman, H., Doubad, D., Asokumar, A. & Matheson, K. Psychosocial and neurobiological aspects of the worldwide refugee crisis: From vulnerability to resilience. NEUROSCI BIOBEHAV REV, XXXX. Immigration occurs between countries either to obtain employment, for family reunification or to escape violence and other life-threatening conditions. Refugees and asylum seekers are often obligated to overcome a uniquely challenging set of circumstances prior to and during migration. Settlement following immigration may pose yet another set of stressors related to acculturation to the host country, as well as financial insecurity, discrimination, language barriers, and social isolation. Here we discuss the multiple consequences of immigration experiences, focusing on the health disturbances that frequently develop in adults and children. Aside from the psychosocial influences, immigration-related challenges may cause hormonal, inflammatory immune, and microbiota changes that favor psychological and physical illnesses. Some biological alterations are subject to modification by epigenetic changes, which have implications for intergenerational trauma transmission, as might disruptions in parenting behaviors and family dysfunction. Despite the hardships experienced, many immigrants and their families exhibit positive psychological adjustment after resettlement. We provide information to diminish the impacts associated with immigration and offer strength-based approaches that may foster resilience.

Profiling the fecal microbiome and its modulators across the lifespan in the Netherlands

Defining what constitutes a healthy microbiome throughout our lives remains an ongoing challenge. Understanding to what extent host and environmental factors can influence it has been the primary motivation for large population studies worldwide. Here, we describe the fecal microbiome of 3,746 individuals (0-87 years of age) in a nationwide study in the Netherlands, in association with extensive questionnaires. We validate previous findings, such as infant-adult trajectories, and explore the collective impact of our variables, which explain over 40% of the variation in microbiome composition. We identify associations with less explored factors, particularly those ethnic related, which show the largest impact on the adult microbiome composition, diversity, metabolic profiles, and CAZy (carbohydrate-active enzyme) repertoires. Understanding the sources of microbiome variability is crucial, given its potential as a modifiable target with therapeutic possibilities. With this work, we aim to serve as a foundational element for the design of health interventions and fundamental research.

Comparative genomics reveal a novel phylotaxonomic order in the genus Fusobacterium

Fusobacteria have been associated to different diseases, including colorectal cancer (CRC), but knowledge of which taxonomic groups contribute to specific conditions is incomplete. We analyzed the genetic diversity and relationships within the Fusobacterium genus. We report recent and ancestral recombination in core genes, indicating that fusobacteria have mosaic genomes and emphasizing that taxonomic demarcation should not rely on single genes/gene regions. Across databases, we found ample evidence of species miss-classification and of undescribed species, which are both expected to complicate disease association. By focusing on a lineage that includes F. periodonticum/pseudoperiodonticum and F. nucleatum, we show that genomes belong to four modern populations, but most known species/subspecies emerged from individual ancestral populations. Of these, the F. periodonticum/pseudoperiodonticum population experienced the lowest drift and displays the highest genetic diversity, in line with the less specialized distribution of these bacteria in oral sites. A highly drifted ancestral population instead contributed genetic ancestry to a new species, which includes genomes classified within the F. nucleatum animalis diversity in a recent CRC study. Thus, evidence herein calls for a re-analysis of F. nucleatum animalis features associated to CRC. More generally, our data inform future molecular profiling approaches to investigate the epidemiology of Fusobacterium-associated diseases.

Population-specific differences in the human microbiome: Factors defining the diversity

Differences in microbial communities at different body habitats define the microbiome composition of the human body. The gut, oral, skin vaginal fluid and tissue microbiome, are pivotal for human development and immune response and cross talk between these microbiomes is evident. Population studies reveal that various factors, such as host genetics, diet, lifestyle, aging, and geographical location are strongly associated with population-specific microbiome differences. The present review discusses the factors that shape microbiome diversity in humans, and microbiome differences in African, Asian and Caucasian populations. Gut microbiome studies show that microbial species Bacteroides is commonly found in individuals living in Western countries (Caucasian populations), while Prevotella is prevalent in non-Western countries (African and Asian populations). This association is mainly due to the high carbohydrate, high fat diet in western countries in contrast to high fibre, low fat diets in African/ Asian regions. Majority of the microbiome studies focus on the bacteriome component; however, interesting findings reveal that increased bacteriophage richness, which makes up the virome component, correlates with decreased bacterial diversity, and causes microbiome dysbiosis. An increase of Caudovirales (bacteriophages) is associated with a decrease in enteric bacteria in inflammatory bowel diseases. Future microbiome studies should evaluate the interrelation between bacteriome and virome to fully understand their significance in the pathogenesis and progression of human diseases. With ethnic health disparities becoming increasingly apparent, studies need to emphasize on the association of population-specific microbiome differences and human diseases, to develop microbiome-based therapeutics. Additionally, targeted phage therapy is emerging as an attractive alternative to antibiotics for bacterial infections. With rapid rise in microbiome research, focus should be on standardizing protocols, advanced bioinformatics tools, and reducing sequencing platform related biases. Ultimately, integration of multi-omics data (genomics, transcriptomics, proteomics and metabolomics) will lead to precision models for personalized microbiome therapeutics advancement.

Protective and stochastic correlation between infectious diseases and autoimmune disorders

A priori, early exposure to a wide range of bacteria, viruses, and parasites appears to fortify and regulate the immune system, potentially reducing the risk of autoimmune diseases. However, improving hygiene conditions in numerous societies has led to a reduction in these microbial exposures, which, according to certain theories, could contribute to an increase in autoimmune diseases. Indeed, molecular mimicry is a key factor triggering immune system reactions; while it seeks pathogens, it can bind to self-molecules, leading to autoimmune diseases associated with microbial infections. On the other hand, a hygiene-based approach aimed at reducing the load of infectious agents through better personal hygiene can be beneficial for such pathologies. This review sheds light on how the evolution of the innate immune system, following the evolution of molecular patterns associated with microbes, contributes to our protection but may also trigger autoimmune diseases linked to microbes. Furthermore, it addresses how hygiene conditions shield us against autoimmune diseases related to microbes but may lead to autoimmune pathologies not associated with microbes.

Field and laboratory guidelines for reliable bioinformatic and statistical analysis of bacterial shotgun metagenomic data

Shotgun metagenomics is an increasingly cost-effective approach for profiling environmental and host-associated microbial communities. However, due to the complexity of both microbiomes and the molecular techniques required to analyze them, the reliability and representativeness of the results are contingent upon the field, laboratory, and bioinformatic procedures employed. Here, we consider 15 field and laboratory issues that critically impact downstream bioinformatic and statistical data processing, as well as result interpretation, in bacterial shotgun metagenomic studies. The issues we consider encompass intrinsic properties of samples, study design, and laboratory-processing strategies. We identify the links of field and laboratory steps with downstream analytical procedures, explain the means for detecting potential pitfalls, and propose mitigation measures to overcome or minimize their impact in metagenomic studies. We anticipate that our guidelines will assist data scientists in appropriately processing and interpreting their data, while aiding field and laboratory researchers to implement strategies for improving the quality of the generated results.

Role of gut microbiome in the outcome of lymphoma patients treated with checkpoint inhibitors-The MicroLinf Study

Biomarkers for immune checkpoint inhibitors (ICIs) response and resistance include PD-L1 expression and other environmental factors, among which the gut microbiome (GM) is gaining increasing interest especially in lymphomas. To explore the potential role of GM in this clinical issue, feces of 30 relapsed/refractory lymphoma (Hodgkin and primary mediastinal B-cell lymphoma) patients undergoing ICIs were collected from start to end of treatment (EoT). GM was profiled through Illumina, that is, 16S rRNA sequencing, and subsequently processed through a bioinformatics pipeline. The overall response rate to ICIs was 30.5%, with no association between patients clinical characteristics and response/survival outcomes. Regarding GM, responder patients showed a peculiar significant enrichment of Lachnospira, while non-responder ones showed higher presence of Enterobacteriaceae (at baseline and maintained till EoT). Recognizing patient-related factors that may influence response to ICIs is becoming critical to optimize the treatment pathway of heavily pretreated, young patients with a potentially long-life expectancy. These preliminary results indicate potential early GM signatures of ICIs response in lymphoma, which could pave the way for future research to improve patients prognosis with new adjuvant strategies.

Preliminary profile of the gut microbiota from amerindians in the Brazilian amazon experiencing a process of transition to urbanization

The Yanomami are one of the oldest indigenous tribes in the Amazon and are direct descendants of the first people to colonize South America 12,000 years ago. They are located on the border between Venezuela and Brazil, with the Venezuelan side remaining uncontacted. While they maintain a hunter-gatherer society, they are currently experiencing contact with urbanized populations in Brazil. The human gut microbiota of traditional communities has become the subject of recent studies due to the Westernization of their diet and the introduction of antibiotics and other chemicals, which have affected microbial diversity in indigenous populations, thereby threatening their existence. In this study, we preliminarily characterized the diversity of the gut microbiota of the Yanomami, a hunter-gatherer society from the Amazon, experiencing contact with urbanized populations. Similarly, we compared their diversity with the population in Manaus, Amazonas. A metabarcoding approach of the 16 S rRNA gene was carried out on fecal samples. Differences were found between the two populations, particularly regarding the abundance of genera (e.g., Prevotella and Bacteroides) and the higher values of the phyla Bacteroidetes over Firmicutes, which were significant only in the Yanomami. Some bacteria were found exclusively in the Yanomami (Treponema and Succinivibrio). However, diversity was statistically equal between them. In conclusion, the composition of the Yanomami gut microbiota still maintains the profile characteristic of a community with a traditional lifestyle. However, our results suggest an underlying Westernization process of the Yanomami microbiota when compared with that of Manaus, which must be carefully monitored by authorities, as the loss of diversity can be a sign of growing danger to the health of the Yanomami.

Host diet drives gut microbiome convergence between coral reef fishes and mammals

Animal gut microbiomes are critical to host physiology and fitness. The gut microbiomes of fishes-the most abundant and diverse vertebrate clade-have received little attention relative to other clades. Coral reef fishes, in particular, make up a wide range of evolutionary histories and feeding ecologies that are likely associated with gut microbiome diversity. The repeated evolution of herbivory in fishes and mammals also allows us to examine microbiome similarity in relationship to diet across the entire vertebrate tree of life. Here, we generate a large coral reef fish gut microbiome dataset (n = 499 samples, 19 species) and combine it with a diverse aggregation of public microbiome data (n = 447) to show that host diet drives significant convergence between coral reef fish and mammalian gut microbiomes. We demonstrate that this similarity is largely driven by carnivory and herbivory and that herbivorous and carnivorous hosts exhibit distinct microbial compositions across fish and mammals. We also show that fish and mammal gut microbiomes share prominent microbial taxa, including Ruminoccocus spp. and Akkermansia spp., and predicted metabolic pathways. Despite the major evolutionary and ecological differences between fishes and mammals, our results reveal that their gut microbiomes undergo similar dietary selective pressures. Thus, diet, in addition to phylosymbiosis must be considered even when comparing the gut microbiomes of distantly related hosts.

Intestinal Blastocystis is linked to healthier diets and more favorable cardiometabolic outcomes in 56,989 individuals from 32 countries

Diet impacts human health, influencing body adiposity and the risk of developing cardiometabolic diseases. The gut microbiome is a key player in the diet-health axis, but while its bacterial fraction is widely studied, the role of micro-eukaryotes, including Blastocystis, is underexplored. We performed a global-scale analysis on 56,989 metagenomes and showed that human Blastocystis exhibits distinct prevalence patterns linked to geography, lifestyle, and dietary habits. Blastocystis presence defined a specific bacterial signature and was positively associated with more favorable cardiometabolic profiles and negatively with obesity (p < 1e-16) and disorders linked to altered gut ecology (p < 1e-8). In a diet intervention study involving 1,124 individuals, improvements in dietary quality were linked to weight loss and increases in Blastocystis prevalence (p = 0.003) and abundance (p < 1e-7). Our findings suggest a potentially beneficial role for Blastocystis, which may help explain personalized host responses to diet and downstream disease etiopathogenesis.

Diet, Microbiome, and Inflammation Predictors of Fecal and Plasma Short-Chain Fatty Acids in Humans

BACKGROUND

Gut microbes produce short-chain fatty acids (SCFAs), which are associated with broad health benefits. However, it is not fully known how diet and/or the gut microbiome could be modulated to improve SCFA production.

OBJECTIVES

The objective of this study was to identify dietary, inflammatory, and/or microbiome predictors of SCFAs in a cohort of healthy adults.

METHODS

SCFAs were measured in fecal and plasma samples from 359 healthy adults in the United States Department of Agriculture Nutritional Phenotyping Study. Habitual and recent diet was assessed using a food frequency questionnaire and automated self-administered 24-h dietary assessment tool dietary recalls. Markers of systemic and gut inflammation were measured in fecal and plasma samples. The gut microbiome was assessed using shotgun metagenomics. Using statistics and machine learning, we determined how the abundance and composition of SCFAs varied with measures of diet, inflammation, and the gut microbiome.

RESULTS

We show that fecal pH may be a good proxy for fecal SCFA abundance. A higher healthy eating index for a habitual diet was associated with a compositional increase in fecal butyrate relative to acetate and propionate. SCFAs were associated with markers of subclinical gastrointestinal (GI) inflammation. Fecal SCFA abundance was inversely related to plasma lipopolysaccharide-binding protein. When we analyzed hierarchically organized diet and microbiome data with taxonomy-aware algorithms, we observed that diet and microbiome features were far more predictive of fecal SCFA abundances compared to plasma SCFA abundances. The top diet and microbiome predictors of fecal butyrate included potatoes and the thiamine biosynthesis pathway, respectively.

CONCLUSIONS

These results suggest that resistant starch in the form of potatoes and microbially produced thiamine provide a substrate and essential cofactor, respectively, for butyrate synthesis. Thiamine may be a rate-limiting nutrient for butyrate production in adults. Overall, these findings illustrate the complex biology underpinning SCFA production in the gut. This trial was registered at clinicaltrials.gov as NCT02367287.

Western diets and chronic diseases

'Westernization', which incorporates industrial, cultural and dietary trends, has paralleled the rise of noncommunicable diseases across the globe. Today, the Western-style diet emerges as a key stimulus for gut microbial vulnerability, chronic inflammation and chronic diseases, affecting mainly the cardiovascular system, systemic metabolism and the gut. Here we review the diet of modern times and evaluate the threat it poses for human health by summarizing recent epidemiological, translational and clinical studies. We discuss the links between diet and disease in the context of obesity and type 2 diabetes, cardiovascular diseases, gut and liver diseases and solid malignancies. We collectively interpret the evidence and its limitations and discuss future challenges and strategies to overcome these. We argue that healthcare professionals and societies must react today to the detrimental effects of the Western diet to bring about sustainable change and improved outcomes in the future.

Phylogeny and disease associations of a widespread and ancient intestinal bacteriophage lineage

Viruses are core components of the human microbiome, impacting health through interactions with gut bacteria and the immune system. Most human microbiome viruses are bacteriophages, which exclusively infect bacteria. Until recently, most gut virome studies focused on low taxonomic resolution (e.g., viral operational taxonomic units), hampering population-level analyses. We previously identified an expansive and widespread bacteriophage lineage in inhabitants of Amsterdam, the Netherlands. Here, we study their biodiversity and evolution in various human populations. Based on a phylogeny using sequences from six viral genome databases, we propose the Candidatus order Heliusvirales. We identify heliusviruses in 82% of 5441 individuals across 39 studies, and in nine metagenomes from humans that lived in Europe and North America between 1000 and 5000 years ago. We show that a large lineage started to diversify when Homo sapiens first appeared some 300,000 years ago. Ancient peoples and modern hunter-gatherers have distinct Ca. Heliusvirales populations with lower richness than modern urbanized people. Urbanized people suffering from type 1 and type 2 diabetes, as well as inflammatory bowel disease, have higher Ca. Heliusvirales richness than healthy controls. We thus conclude that these ancient core members of the human gut virome have thrived with increasingly westernized lifestyles.

The interplay between diet and the gut microbiome: implications for health and disease

Diet has a pivotal role in shaping the composition, function and diversity of the gut microbiome, with various diets having a profound impact on the stability, functionality and diversity of the microbial community within our gut. Understanding the profound impact of varied diets on the microbiome is crucial, as it will enable us not only to make well-informed dietary decisions for better metabolic and intestinal health, but also to prevent and slow the onset of specific diet-related diseases that stem from suboptimal diets. In this Review, we explore how geographical location affects the gut microbiome and how different diets shape its composition and function. We examine the mechanisms by which whole dietary regimes, such as the Mediterranean diet, high-fibre diet, plant-based diet, high-protein diet, ketogenic diet and Western diet, influence the gut microbiome. Furthermore, we underscore the need for exhaustive studies to better understand the causal relationship between diet, host and microorganisms for the development of precision nutrition and microbiome-based therapies.

Unraveling the Evolutionary Diet Mismatch and Its Contribution to the Deterioration of Body Composition

Over the millennia, patterns of food consumption have changed; however, foods were always whole foods. Ultra-processed foods (UPFs) have been a very recent development and have become the primary food source for many people. The purpose of this review is to propose the hypothesis that, forsaking the evolutionary dietary environment, and its complex milieu of compounds resulting in an extensive metabolome, contributes to chronic disease in modern humans. This evolutionary metabolome may have contributed to the success of early hominins. This hypothesis is based on the following assumptions: (1) whole foods promote health, (2) essential nutrients cannot explain all the benefits of whole foods, (3) UPFs are much lower in phytonutrients and other compounds compared to whole foods, and (4) evolutionary diets contributed to a more diverse metabolome. Evidence will be presented to support this hypothesis. Nutrition is a matter of systems biology, and investigating the evolutionary metabolome, as compared to the metabolome of modern humans, will help elucidate the hidden connections between diet and health. The effect of the diet on the metabolome may also help shape future dietary guidelines, and help define healthy foods.

Microbiota, natural products, and human health: exploring interactions for therapeutic insights

The symbiotic relationship between the human digestive system and its intricate microbiota is a captivating field of study that continues to unfold. Comprising predominantly anaerobic bacteria, this complex microbial ecosystem, teeming with trillions of organisms, plays a crucial role in various physiological processes. Beyond its primary function in breaking down indigestible dietary components, this microbial community significantly influences immune system modulation, central nervous system function, and disease prevention. Despite the strides made in microbiome research, the precise mechanisms underlying how bacterial effector functions impact mammalian and microbiome physiology remain elusive. Unlike the traditional DNA-RNA-protein paradigm, bacteria often communicate through small molecules, underscoring the imperative to identify compounds produced by human-associated bacteria. The gut microbiome emerges as a linchpin in the transformation of natural products, generating metabolites with distinct physiological functions. Unraveling these microbial transformations holds the key to understanding the pharmacological activities and metabolic mechanisms of natural products. Notably, the potential to leverage gut microorganisms for large-scale synthesis of bioactive compounds remains an underexplored frontier with promising implications. This review serves as a synthesis of current knowledge, shedding light on the dynamic interplay between natural products, bacteria, and human health. In doing so, it contributes to our evolving comprehension of microbiome dynamics, opening avenues for innovative applications in medicine and therapeutics. As we delve deeper into this intricate web of interactions, the prospect of harnessing the power of the gut microbiome for transformative medical interventions becomes increasingly tantalizing.

Nepali oral microbiomes reflect a gradient of lifestyles from traditional to industrialized

Background

Lifestyle plays an important role in shaping the gut microbiome. However, its contributions to the oral microbiome remains less clear, due to the confounding effects of geography and methodology in investigations of populations studied to date. Furthermore, while the oral microbiome seems to differ between foraging and industrialized populations, we lack insight into whether transitions to and away from agrarian lifestyles shape the oral microbiota. Given the growing interest in so-called 'vanishing microbiomes' potentially being a risk factor for increased disease prevalence in industrialized populations, it is important that we distinguish lifestyle from geography in the study of microbiomes across populations.

Results

Here, we investigate salivary microbiomes of 63 Nepali individuals representing a spectrum of lifestyles: foraging, subsistence farming (individuals that transitioned from foraging to farming within the last 50 years), agriculturalists (individuals that have transitioned to farming for at least 300 years), and industrialists (expatriates that immigrated to the United States within the last 20 years). We characterize the role of lifestyle in microbial diversity, identify microbes that differ between lifestyles, and pinpoint specific lifestyle factors that may be contributing to differences in the microbiomes across populations. Contrary to prevailing views, when geography is controlled for, oral microbiome alpha diversity does not differ significantly across lifestyles. Microbiome composition, however, follows the gradient of lifestyles from foraging through agrarianism to industrialism, supporting the notion that lifestyle indeed plays a role in the oral microbiome. Relative abundances of several individual taxa, including Streptobacillus and an unclassified Porphyromonadaceae genus, also mirror lifestyle. Finally, we identify specific lifestyle factors associated with microbiome composition across the gradient of lifestyles, including smoking and grain source.

Conclusion

Our findings demonstrate that by controlling for geography, we can isolate an important role for lifestyle in determining oral microbiome composition. In doing so, we highlight the potential contributions of several lifestyle factors, underlining the importance of carefully examining the oral microbiome across lifestyles to improve our understanding of global microbiomes.

The Conservation Implications of the Gut Microbiome for Protecting the Critically Endangered Gray Snub-Nosed Monkey (Rhinopithecus brelichi)

The gut microbiota plays a crucial role in regulating energy metabolism, facilitating nutrient absorption, and supporting immune function, thereby assisting the host in adapting to seasonal dietary changes. Here, we compare the gut microbiome composition of wild gray snub-nosed monkeys during winter (from October to December) and spring (from January to March) to understand differences in seasonal nutrient intake patterns. Snub-nosed monkeys are foregut fermenters and consume difficult-to-digest carbohydrates and lichen. To examine the digestive adaptations of gray snub-nosed monkeys, we collected 14 fresh fecal samples for DNA analysis during the winter and spring. Based on 16S rRNA sequencing, metagenomic sequencing, and functional metagenomic analyses, we identified that Firmicutes, Actinobacteria, Verrucomicrobia, and Bacteroidetes constitute a keystone bacterial group in the gut microbiota during winter and spring and are responsible for degrading cellulose. Moreover, the transition in dietary composition from winter to spring was accompanied by changes in gut microbiota composition, demonstrating adaptive responses to varying food sources and availability. In winter, the bacterial species of the genera Streptococcus were found in higher abundance. At the functional level, these bacteria are involved in fructose and mannose metabolism and galactose metabolism c-related pathways, which facilitate the breakdown of glycogen, starch, and fiber found in fruits, seeds, and mature leaves. During spring, there was an increased abundance of bacteria species from the Prevotella and Lactobacillus genera, which aid the digestion of protein-rich buds. Combined, these findings reveal how the gut microbiota adjusts to fluctuations in energy balance and nutrient intake across different seasons in this critically endangered species. Moreover, we also identified Pseudomonas in two samples; the presence of potential pathogens within the gut could pose a risk to other troop members. Our findings highlight the necessity of a conservation plan that focuses on protecting vegetation and implementing measures to prevent disease transmission for this critically endangered species.

The relationship between the gut microbiota and thyroid disorders

Disorders of the thyroid gland are common, more prevalent in women than in men, and range from inflammatory to neoplastic lesions. Autoimmune thyroid diseases (AITD) affect 2-5% of the population, while thyroid cancer is the most frequent endocrine malignancy. Treatment for AITD is still restricted to management rather than prevention or cure. Progress has been made in identifying genetic variants that predispose to AITD and thyroid cancer, but the increasing prevalence of all thyroid disorders indicates that factors other than genes are involved. The gut microbiota, which begins to develop before birth, is highly sensitive to diet and the environment, providing a potential mechanism for non-communicable diseases to become communicable. Its functions extend beyond maintenance of gut integrity: the gut microbiota regulates the immune system, contributes to thyroid hormone metabolism and can generate or catabolize carcinogens, all of which are relevant to AITD and thyroid cancer. Observational and interventional studies in animal models support a role for the gut microbiota in AITD, which has been confirmed in some reports from human cohorts, although considerable geographic variation is apparent. Reports of a role for the microbiota in thyroid cancer are more limited, but evidence supports a relationship between gut dysbiosis and thyroid cancer.

Short-term dietary fiber interventions produce consistent gut microbiome responses across studies

The composition of the human gut microbiome varies tremendously among individuals, making the effects of dietary or treatment interventions difficult to detect and characterize. The consumption of fiber is important for gut health, yet the specific effects of increased fiber intake on the gut microbiome vary across studies. The variation in study outcomes might be due to inter-individual (or inter-population) variation or to the details of the interventions including the types of fiber, length of study, size of cohort, and molecular approaches. Thus, to identify generally (on average) consistent fiber-induced responses in the gut microbiome of healthy individuals, we re-analyzed 16S rRNA sequencing data from 21 dietary fiber interventions from 12 human studies, which included 2,564 fecal samples from 538 subjects across all interventions. Short-term increases in dietary fiber consumption resulted in highly consistent gut bacterial community responses across studies. Increased fiber consumption explained an average of 1.5% of compositional variation (vs 82% of variation attributed to the individual), reduced alpha-diversity, and resulted in phylogenetically conserved responses in relative abundances among bacterial taxa. Additionally, we identified bacterial clades, at approximately the genus level, that were highly consistent in their response (on average, increasing or decreasing in their relative abundance) to dietary fiber interventions across the studies.

IMPORTANCE

Our study is an example of the power of synthesizing and reanalyzing 16S rRNA microbiome data from many intervention studies. Despite high inter-individual variation of the composition of the human gut microbiome, dietary fiber interventions cause a consistent response both in the degree of change and the particular taxa that respond to increased fiber.

What Can the Gut Microbiota of Animals Teach Us about the Relationship between Nutrition and Burden of Lifestyle Diseases?

The gut microbiota performs several crucial roles in a holobiont with its host, including immune regulation, nutrient absorption, synthesis, and defense against external pathogens, significantly influencing host physiology. Disruption of the gut microbiota has been linked to various chronic conditions, including cardiovascular, kidney, liver, respiratory, and intestinal diseases. Studying how animals adapt their gut microbiota across their life course at different life stages and under the dynamics of extreme environmental conditions can provide valuable insights from the natural world into how the microbiota modulates host biology, with a view to translating these into treatments or preventative measures for human diseases. By modulating the gut microbiota, opportunities to address many complications associated with chronic diseases appear. Such a biomimetic approach holds promise for exploring new strategies in healthcare and disease management.

Starter Culture Development and Innovation for Novel Fermented Foods

Interest in fermented foods is increasing because fermented foods are promising solutions for more secure food systems with an increased proportion of minimally processed plant foods and a smaller environmental footprint. These developments also pertain to novel fermented food for which no traditional template exists, raising the question of how to develop starter cultures for such fermentations. This review establishes a framework that integrates traditional and scientific knowledge systems for the selection of suitable cultures. Safety considerations, the use of organisms in traditional food fermentations, and the link of phylogeny to metabolic properties provide criteria for culture selection. Such approaches can also select for microbial strains that have health benefits. A science-based approach to the development of novel fermented foods can substantially advance their value through more secure food systems, food products that provide health-promoting microbes, and the provision of foods that improve human health.

The gut microbiota in adults with chronic intestinal failure

OBJECTIVE

Fecal microbiota was investigated in adult patients with chronic intestinal failure (CIF) due to short bowel syndrome (SBS) with jejunocolonic anastomosis (SBS-2). Few or no data are available on SBS with jejunostomy (SBS-1) and CIF due to intestinal dysmotility (DYS) or mucosal disease (MD). We profiled the fecal microbiota of various pathophysiological mechanisms of CIF.

METHODS

Cross-sectional study on 61 adults with CIF (SBS-1 30, SBS-2 17, DYS 8, MD 6). Fecal samples were collected and profiled by 16S rRNA amplicon sequencing. Healthy controls (HC) were selected from pre-existing cohorts, matched with patients by sex and age.

RESULTS

Compared to HC, SBS-1, SBS-2 and MD patients showed lower alpha diversity; no difference was found for DYS. In beta diversity analysis, SBS-1, SBS-2 and DYS groups segregated from HC and from each other. Taxonomically, the CIF groups differed from HC even at the phylum level. In particular, CIF patients' microbiota was dominated by Lactobacillaceae and Enterobacteriaceae, while depleted in typical health-associated taxa belonging to Lachnospiraceae and Ruminococcaceae. Notably, compositional peculiarities of the CIF groups emerged. Furthermore, in the SBS groups, the microbiota profile differed according to the amount of parenteral nutrition required and the duration of CIF.

CONCLUSIONS

CIF patients showed marked intestinal dysbiosis with microbial signatures specific to the pathophysiological mechanism of CIF as well as to the severity and duration of SBS.

Gut microbiota in centenarians: A potential metabolic and aging regulator in the study of extreme longevity

Centenarians, those aged 100 years or older, are considered the most successful biological aging model in humans. This population is commonly characterized by a low prevalence of chronic diseases, with favorable maintenance of functionality and independence, thus determining a health phenotype of successful aging. There are many factors usually associated with extreme longevity: genetics, lifestyles, diet, among others. However, it is most likely a multifactorial condition where protective factors contribute individually to some extent. The gut microbiota (GM) has emerged as a potential factor associated with the establishment of a favorable health phenotype that allows for extreme longevity, as seen in centenarians. To understand the possible impact generated by the GM, its changes, and the probable causes for successful aging, the aim of this review was to synthesize evidence on the role of the GM as a potential protective factor for achieving extreme longevity, using its relationship with centenarians.

Extreme mortality during a historical measles outbreak on Rotuma is consistent with measles immunosuppression

Until the early twentieth century, populations on many Pacific Islands had never experienced measles. As travel to the Pacific Islands by Europeans became more common, the arrival of measles and other pathogens had devastating consequences. In 1911, Rotuma in Fiji was hit by a measles epidemic, which killed 13% of the island population. Detailed records show two mortality peaks, with individuals reported as dying solely from measles in the first and from measles and diarrhoea in the second. Measles is known to disrupt immune system function. Here, we investigate whether the pattern of mortality on Rotuma in 1911 was a consequence of the immunosuppressive effects of measles. We use a compartmental model to simulate measles infection and immunosuppression. Whilst immunosuppressed, we assume that individuals are vulnerable to dysfunctional reactions triggered by either (i) a newly introduced infectious agent arriving at the same time as measles or (ii) microbes already present in the population in a pre-existing equilibrium state. We show that both forms of the immunosuppression model provide a plausible fit to the data and that the inclusion of immunosuppression in the model leads to more realistic estimates of measles epidemiological parameters than when immunosuppression is not included.

Influence of Compost Amendments on Soil and Human Gastrointestinal Bacterial Communities during a Single Gardening Season

To measure associations between gardening with different compost amendments and the human gut microbiota composition, gardeners (n = 25) were provided with one of three types of compost: chicken manure (CM), dairy manure and plant material (DMP), or plant-based (P). Stool samples were collected before gardening (T1), after compost amendment (T2), and at peak garden harvest (T3). Compost and soil samples were collected. DNA was extracted, 16S rRNA libraries were established, and libraries were sequenced by Illumina MiSeq. Sequences were processed using mothur, and data were analyzed in R software version 4.2.2. Fast expectation-maximization microbial source tracking analysis was used to determine stool bacteria sources. At T2/T3, the gut microbiotas of P participants had the lowest Shannon alpha diversity, which was also the trend at T1. In stool from T2, Ruminococcus 1 were less abundant in the microbiotas of those using P compost as compared to those using CM or DMP. At T2, Prevotella 9 had the highest abundance in the microbiotas of those using CM compost. In participants who used CM compost to amend their gardening plots, a larger proportion of the human stool bacteria were sourced from CM compared to soil. Soil exposure through gardening was associated with a small but detectable change in the gardeners' gut microbiota composition. These results suggest that human interactions with soil through gardening could potentially impact health through alterations to the gut microbiota.

The gut commensal Blautia maintains colonic mucus function under low-fiber consumption through secretion of short-chain fatty acids

Beneficial gut bacteria are indispensable for developing colonic mucus and fully establishing its protective function against intestinal microorganisms. Low-fiber diet consumption alters the gut bacterial configuration and disturbs this microbe-mucus interaction, but the specific bacteria and microbial metabolites responsible for maintaining mucus function remain poorly understood. By using human-to-mouse microbiota transplantation and ex vivo analysis of colonic mucus function, we here show as a proof-of-concept that individuals who increase their daily dietary fiber intake can improve the capacity of their gut microbiota to prevent diet-mediated mucus defects. Mucus growth, a critical feature of intact colonic mucus, correlated with the abundance of the gut commensal Blautia, and supplementation of Blautia coccoides to mice confirmed its mucus-stimulating capacity. Mechanistically, B. coccoides stimulated mucus growth through the production of the short-chain fatty acids propionate and acetate via activation of the short-chain fatty acid receptor Ffar2, which could serve as a new target to restore mucus growth during mucus-associated lifestyle diseases.

Fermented foods and gastrointestinal health: underlying mechanisms

Although fermentation probably originally developed as a means of preserving food substrates, many fermented foods (FFs), and components therein, are thought to have a beneficial effect on various aspects of human health, and gastrointestinal health in particular. It is important that any such perceived benefits are underpinned by rigorous scientific research to understand the associated mechanisms of action. Here, we review in vitro, ex vivo and in vivo studies that have provided insights into the ways in which the specific food components, including FF microorganisms and a variety of bioactives, can contribute to health-promoting activities. More specifically, we draw on representative examples of FFs to discuss the mechanisms through which functional components are produced or enriched during fermentation (such as bioactive peptides and exopolysaccharides), potentially toxic or harmful compounds (such as phytic acid, mycotoxins and lactose) are removed from the food substrate, and how the introduction of fermentation-associated live or dead microorganisms, or components thereof, to the gut can convey health benefits. These studies, combined with a deeper understanding of the microbial composition of a wider variety of modern and traditional FFs, can facilitate the future optimization of FFs, and associated microorganisms, to retain and maximize beneficial effects in the gut.

Gut microbiota differences in stunted and normal-lenght children aged 36-45 months in East Nusa Tenggara, Indonesia

The role of the gut microbiota in energy metabolism of the host has been established, both in overweight/obesity, as well as in undernutrition/stunting. Dysbiosis of the gut microbiota may predispose to stunting. The aim of this study was to compare the gut microbiota composition of stunted Indonesian children and non-stunted children between 36 and 45 months from two sites on the East Nusa Tenggara (ENT) islands. Fecal samples were collected from 100 stunted children and 100 non-stunted children in Kupang and North Kodi. The gut microbiota composition was determined by sequencing amplicons of the V3-V4 region of the 16S rRNA gene. Moreover, fecal SCFA concentrations were analyzed. The microbiota composition was correlated to anthropometric parameters and fecal metabolites. The phyla Bacteroidetes (Bacteroidota; q = 0.014) and Cyanobacteria (q = 0.049) were significantly higher in stunted children. Three taxa at genus levels were consistently significantly higher in stunted children at both sampling sites, namely Lachnoclostridium, Faecalibacterium and Veillonella (q < 7 * 10-4). These and 9 other taxa positively correlated to the z-score length-for-age (zlen), while 11 taxa negatively correlated with zlen. Several taxa also correlated with sanitary parameters, some of which were also significantly different between the two groups. All three fecal SCFA concentrations (acetate, propionate and butyrate) and their total were lower in stunted children compared to non-stunted children, although not significant for butyrate, indicating lower energy-extraction by the gut microbiota. Also, since SCFA have been shown to be involved in gut barrier function, barrier integrity may be affected in the stunted children. It remains to be seen if the three taxa are involved in stunting, or are changed due to e.g. differences in diet, hygiene status, or other factors. The observed differences in this study do not agree with our previous observations in children on Java, Indonesia. There are differences in infrastructure facilities such as clean water and sanitation on ENT and Java, which may contribute to the differences observed. The role of the gut microbiota in stunting therefore requires more in depth studies. Trial registration: the trial was registered at ClinicalTrials.gov with identifier number NCT05119218.

Understanding the gut microbiota by considering human evolution: a story of fire, cereals, cooking, molecular ingenuity, and functional cooperation

SUMMARYThe microbial community inhabiting the human colon, referred to as the gut microbiota, is mostly composed of bacterial species that, through extensive metabolic networking, degrade and ferment components of food and human secretions. The taxonomic composition of the microbiota has been extensively investigated in metagenomic studies that have also revealed details of molecular processes by which common components of the human diet are metabolized by specific members of the microbiota. Most studies of the gut microbiota aim to detect deviations in microbiota composition in patients relative to controls in the hope of showing that some diseases and conditions are due to or exacerbated by alterations to the gut microbiota. The aim of this review is to consider the gut microbiota in relation to the evolution of Homo sapiens which was heavily influenced by the consumption of a nutrient-dense non-arboreal diet, limited gut storage capacity, and acquisition of skills relating to mastering fire, cooking, and cultivation of cereal crops. The review delves into the past to gain an appreciation of what is important in the present. A holistic view of "healthy" microbiota function is proposed based on the evolutionary pathway shared by humans and gut microbes.

Establishment of a non-Westernized gut microbiota in men who have sex with men is associated with sexual practices

The human gut microbiota is influenced by various factors, including health status and environmental conditions, yet considerable inter-individual differences remain unexplained. Previous studies identified that the gut microbiota of men who have sex with men (MSM) is distinct from that of non-MSM. Here, we reveal through species-level microbiota analysis using shotgun metagenomics that the gut microbiota of many MSM with Western origin resembles gut microbial communities of non-Westernized populations. Specifically, MSM gut microbiomes are frequently dominated by members of the Prevotellaceae family, including co-colonization of species from the Segatella copri complex and unknown Prevotellaceae members. Questionnaire-based analysis exploring inter-individual differences in MSM links specific sexual practices to microbiota composition. Moreover, machine learning identifies microbial features associated with sexual activities in MSM. Together, this study shows associations of sexual activities with gut microbiome alterations in MSM, which may have a large impact on population-based microbiota studies.

Impact of evolution on lifestyle in microbiome

This chapter analyses the interaction between microbiota and humans from an evolutionary point of view. Long-term interactions between gut microbiota and host have been generated as a result of dietary choices through coevolutionary processes, where mutuality of advantage is essential. Likewise, the characteristics of the intestinal environment have made it possible to describe different intrahost evolutionary mechanisms affecting microbiota. For its part, the intestinal microbiota has been of great importance in the evolution of mammals, allowing the diversification of dietary niches, phenotypic plasticity and the selection of host phenotypes. Although the origin of the human intestinal microbial community is still not known with certainty, mother-offspring transmission plays a key role, and it seems that transmissibility between individuals in adulthood also has important implications. Finally, it should be noted that certain aspects inherent to modern lifestyle, including refined diets, antibiotic intake, exposure to air pollutants, microplastics, and stress, could negatively affect the diversity and composition of our gut microbiota. This chapter aims to combine current knowledge to provide a comprehensive view of the interaction between microbiota and humans throughout evolution.

The gut microbiome of Baka forager-horticulturalists from Cameroon is optimized for wild plant foods

The human gut microbiome is losing biodiversity, due to the "microbiome modernization process" that occurs with urbanization. To keep track of it, here we applied shotgun metagenomics to the gut microbiome of the Baka, a group of forager-horticulturalists from Cameroon, who combine hunting and gathering with growing a few crops and working for neighboring Bantu-speaking farmers. We analyzed the gut microbiome of individuals with different access to and use of wild plant and processed foods, to explore the variation of their gut microbiome along the cline from hunter-gatherer to agricultural subsistence patterns. We found that 26 species-level genome bins from our cohort were pivotal for the degradation of the wild plant food substrates. These microbes include Old Friend species and are encoded for genes that are no longer present in industrialized gut microbiome. Our results highlight the potential relevance of these genes to human biology and health, in relation to lifestyle.

Expanding the human gut microbiome atlas of Africa

Population studies are crucial in understanding the complex interplay between the gut microbiome and geographical, lifestyle, genetic, and environmental factors. However, populations from low- and middle-income countries, which represent ~84% of the world population, have been excluded from large-scale gut microbiome research. Here, we present the AWI-Gen 2 Microbiome Project, a cross-sectional gut microbiome study sampling 1,803 women from Burkina Faso, Ghana, Kenya, and South Africa. By intensively engaging with communities that range from rural and horticultural to urban informal settlements and post-industrial, we capture population diversity that represents a far greater breadth of the world's population. Using shotgun metagenomic sequencing, we find that study site explains substantially more microbial variation than disease status. We identify taxa with strong geographic and lifestyle associations, including loss of Treponema and Cryptobacteroides species and gain of Bifidobacterium species in urban populations. We uncover a wealth of prokaryotic and viral novelty, including 1,005 new bacterial metagenome-assembled genomes, and identify phylogeography signatures in Treponema succinifaciens. Finally, we find a microbiome signature of HIV infection that is defined by several taxa not previously associated with HIV, including Dysosmobacter welbionis and Enterocloster sp. This study represents the largest population-representative survey of gut metagenomes of African individuals to date, and paired with extensive clinical biomarkers, demographic data, and lifestyle information, provides extensive opportunity for microbiome-related discovery and research.

Inverse association between Paleolithic Diet Fraction and mortality and incidence of cardiometabolic disease in the prospective Malmö Diet and Cancer Study

PURPOSE

Paleolithic Diet Fraction (PDF) estimates how large a portion of the absolute dietary intake stems from food groups included in the Paleolithic diet. In randomized controlled trials higher PDFs have been associated with healthier levels of cardiometabolic risk markers. Our aim was to build upon these findings by examining associations between PDF and mortality and incidence of cardiometabolic disease in the prospective Malmö Diet and Cancer Study.

METHODS

PDF was calculated from an interview-based, modified diet history method, and associations were estimated by using multivariable Cox proportional hazards regression. The examined cohort consisted of 24,104 individuals (44-74 years, 63% women) without previous coronary events, diabetes, or stroke at baseline (1992-1996). A total of 10,092 individuals died during a median follow-up of 18 years.

RESULTS

Median PDF was 40% (0-90%). The adjusted hazard ratios (HR) for PDF as a continuous variable (from 0 to 100%) were for risk of death from all causes 0.55 [95% CI 0.45, 0.66], tumor 0.68 [95% CI 0.49, 0.93], cardiovascular 0.55 [95% CI 0.39, 0.78], respiratory 0.44 [95% CI 0.21, 0.90], neurological 0.26 [95% CI 0.11, 0.60], digestive, 0.10 [95% CI 0.03, 0.30], and other diseases 0.64 [95% CI 0.41, 1.00]. The corresponding HR for risk of coronary event was 0.61 [95% 0.43, 0.86], for ischemic stroke it was 0.73 [95% 0.48, 1.09] and for type 2 diabetes it was 0.82 [95% 0.61, 1.10].

CONCLUSION

Observational data suggest an inverse association between PDF and all-cause as well as cause-specific mortality and incidence of cardiometabolic disease.

Documenting the diversity of the Namibian Ju|'hoansi intestinal microbiome

We investigate the bacterial and fungal composition and functionality of the Ju|'hoansi intestinal microbiome (IM). The Juǀ'hoansi are a hunter-gatherer community residing in northeastern Namibia. They formerly subsisted by hunting and gathering but have been increasingly exposed to industrial dietary sources, medicines, and lifestyle features. They present an opportunity to study the evolution of the human IM in situ, from a predominantly hunter-gatherer to an increasingly Western urban-forager-farmer lifestyle. Their bacterial IM resembles that of typical hunter-gatherers, being enriched for genera such as Prevotella, Blautia, Faecalibacterium, Succinivibrio, and Treponema. Fungal IM inhabitants include animal pathogens and plant saprotrophs such as Fusarium, Issatchenkia, and Panellus. Our results suggest that diet and culture exert a greater influence on Ju|'hoansi IM composition than age, self-identified biological sex, and medical history. The Ju|'hoansi exhibit a unique core IM composition that diverges from the core IMs of other populations.

Hunter-gatherer genetics research: Importance and avenues

Major developments in the field of genetics in the past few decades have revolutionised notions of what it means to be human. Although currently only a few populations around the world practise a hunting and gathering lifestyle, this mode of subsistence has characterised members of our species since its very origins and allowed us to migrate across the planet. Therefore, the geographical distribution of hunter-gatherer populations, dependence on local ecosystems and connections to past populations and neighbouring groups have provided unique insights into our evolutionary origins. However, given the vulnerable status of hunter-gatherers worldwide, the development of the field of anthropological genetics requires that we reevaluate how we conduct research with these communities. Here, we review how the inclusion of hunter-gatherer populations in genetics studies has advanced our understanding of human origins, ancient population migrations and interactions as well as phenotypic adaptations and adaptability to different environments, and the important scientific and medical applications of these advancements. At the same time, we highlight the necessity to address yet unresolved questions and identify areas in which the field may benefit from improvements.

Differences in bacterial taxa between treatment-naive patients with major depressive disorder and non-affected controls may be related to a proinflammatory profile

BACKGROUND

Major depressive disorder (MDD) is characterized by sadness and anhedonia, but also physical symptoms such as changes in appetite and weight. Gut microbiota has been hypothesized to be involved in MDD through gut-brain axis signaling. Moreover, antidepressants display antibacterial properties in the gastrointestinal tract. The aim of this study was to compare the gut microbiota and systemic inflammatory profile of young patients with MDD before and after initiation of antidepressant treatment and/or psychotherapy in comparison with a non-depressed control group (nonMDD).

METHODS

Fecal and blood samples were collected at baseline and at follow-up after four and twelve weeks, respectively. Patients started treatment immediately after collection of the baseline samples. The gut microbiota was characterized by 16 S rRNA gene sequencing targeting the hypervariable V4 region. Plasma levels of 49 unique immune markers were assessed using Mesoscale.

RESULTS

In total, 27 MDD patients and 32 nonMDD controls were included in the study. The gut microbiota in the baseline samples of MDD versus nonMDD participants did not differ regarding α- or β-diversity. However, there was a higher relative abundance of the genera Ruminococcus gnavus group, and a lower relative abundance of the genera Desulfovibrio, Tyzzerella, Megamonas, Olsenella, Gordonibacter, Allisonella and Rothia in the MDD group compared to the nonMDD group. In the MDD group, there was an increase in the genera Rothia, Desulfovibrio, Gordinobacteer and Lactobacillus, while genera belonging to the Firmicutes phylum were found depleted at twelve weeks follow-up compared to baseline. In the MDD group, IL-7, IL-8 and IL-17b levels were elevated compared to the nonMDD group at baseline. Furthermore, MDI score in the MDD group was found to correlate with Bray-Curtis dissimilarity at baseline, and several inflammatory markers at both baseline and after initiation of antidepressant treatment.

CONCLUSION

Several bacterial taxa differed between the MDD group and the nonMDD group at baseline and changed in relative abundance during antidepressant treatment and/or psychotherapy. The MDD group was furthermore found to have a pro-inflammatory profile compared to the nonMDD group at baseline. Further studies are required to investigate the gut microbiota and pro-inflammatory profile of patients with MDD.

Nutritional regulation of microbiota-derived metabolites: Implications for immunity and inflammation

Nutrition profoundly shapes immunity and inflammation across the lifespan of mammals, from pre- and post-natal periods to later life. Emerging insights into diet-microbiota interactions indicate that nutrition has a dominant influence on the composition-and metabolic output-of the intestinal microbiota, which in turn has major consequences for host immunity and inflammation. Here, we discuss recent findings that support the concept that dietary effects on microbiota-derived metabolites potently alter immune responses in health and disease. We discuss how specific dietary components and metabolites can be either pro-inflammatory or anti-inflammatory in a context- and tissue-dependent manner during infection, chronic inflammation, and cancer. Together, these studies emphasize the influence of diet-microbiota crosstalk on immune regulation that will have a significant impact on precision nutrition approaches and therapeutic interventions for managing inflammation, infection, and cancer immunotherapy.

What We Can Learn About Emotion by Talking With the Hadza

Emotions are often thought of as internal mental states centering on individuals' subjective feelings and evaluations. This understanding is consistent with studies of emotion narratives, or the descriptions people give for experienced events that they regard as emotions. Yet these studies, and contemporary psychology more generally, often rely on observations of educated Europeans and European Americans, constraining psychological theory and methods. In this article, we present observations from an inductive, qualitative analysis of interviews conducted with the Hadza, a community of small-scale hunter-gatherers in Tanzania, and juxtapose them with a set of interviews conducted with Americans from North Carolina. Although North Carolina event descriptions largely conformed to the assumptions of eurocentric psychological theory, Hadza descriptions foregrounded action and bodily sensations, the physical environment, immediate needs, and the experiences of social others. These observations suggest that subjective feelings and internal mental states may not be the organizing principle of emotion the world around. Qualitative analysis of emotion narratives from outside of a U.S. (and western) cultural context has the potential to uncover additional diversity in meaning-making, offering a descriptive foundation on which to build a more robust and inclusive science of emotion.

A single dietary factor, daily consumption of a fermented beverage, can modulate the gut bacteria and fecal metabolites within the same ethnic community

IMPORTANCE

Our study investigated how a traditional drink called Apong, made from fermented rice, affects the gut and health of the Mishing community in India. We compared two groups of people who drink Apong to a group of people who do not drink it. To accomplish this, we studied the gut bacteria, fecal metabolites, and blood samples of the participants. It was found that the people who drank Apong had higher blood pressure but lower blood sugar and protein levels than people who did not drink it. We also found that the gut microbiome composition of people who drank Apong was different from those who did not drink it. Moreover, people who drank Apong had lower levels of isovaleric acid in their feces. Overall, this study shows that a traditional drink like Apong can affect the gut bacteria of a community.

The study on the impact of sex on the structure of gut microbiota of bamboo rats in China

Introduction

Bamboo rats are rodents that eat bamboo, and their robust capacity for bamboo digestion is directly correlated with their gut flora. Chinese bamboo rat (Rhizomys sinensis) is a common bamboo rat in Chinese central and southern regions. As a single-stomach mammal, bamboo rats are a famous specificity bamboo-eating animal and their intestinal microbial composition may also play a key role in the digestion of cellulose and lignin. So, the gut microbiota of bamboo rat may play an important role in the adaptation of bamboo rats for digesting lignocellulose-based diet.

Methods

To study the microbiome differences of bamboo rats from different sexes, the microbial genomic DNA was extracted from each fecal sample and the V4 region of 16S rRNA genes was amplified and sequencing on an IlluminaHiSeq6000 platform. The operational taxonomic units (OTUs) were classified, the OTUs in different sexes was identified and compared at phylum and genus levels. For isolation and screening of cellulose degradation bacteria from bamboo rats, fresh feces from randomly selected bamboo rats were collected and used for the isolation and screening of cellulose degradation bacteria using Luria Bertani (LB) Agar medium containing Carboxymethyl cellulose. The cellulase activity, biochemical characterization and phylogenetic analysis of the purified bacteria strains were characterized.

Results and discussion

A total of 3,833 OTUs were classified. The total microbial diversity detected in the female and male rats was 3,049 OTUs and 3,452 OTUs, respectively. The Shannon index revealed significant differences between the two groups (p < 0.05), though they were all captive and had the same feeding conditions. At the phylum level, Firmicutes, Bacteroidota, and Proteobacteria were prominent in the microbial community. At the genus level, the microbial community was dominated by Lachnospiraceae, Lactobacillus, Bacteroides, and Prevotella, but there was a significant difference between the two groups of bamboo rats; ~90 bacteria genus in the female group was significantly higher than the male group. Among them, Bacteroides, Colidextribacter, and Oscillibacter were significantly higher genera, and the genera of Lachnoclostridium, Oscillibacter, and Papillibacter had the highest FC value among the male and female bamboo rats. The KEGG function annotation and different pathways analysis revealed that membrane transport, carbohydrate metabolism, and amino acid metabolism were the most enriched metabolic pathways in the two groups, and multiple sugar transport system permease protein (K02025 and K02026), RNA polymerase sigma-70 factor (K03088), and ATP-binding cassette (K06147) were the three different KEGG pathways (p < 0.05). Two cellulose degradation bacteria strains-Bacillus subtilis and Enterococcus faecalis-were isolated and characterized from the feces of bamboo rats.

The impact of wind energy on plant biomass production in China

Global wind power expansion raises concerns about its potential impact on plant biomass production (PBP). Using a high-dimensional fixed effects model, this study reveals significant PBP reduction due to wind farm construction based on 2404 wind farms, 108,361 wind turbines, and 7,904,352 PBP observations during 2000-2022 in China. Within a 1-10 km buffer, the normalized differential vegetation and enhanced vegetation indices decrease from 0.0097 to 0.0045 and 0.0075 to 0.0028, respectively. Similarly, absorbed photosynthetically active radiation and gross primary productivity decline from 0.0094 to 0.0034% and 0.0003-0.0002 g*C/m2 within a 1-7 km buffer. Adverse effects last over three years, magnified in summer and autumn, and are more pronounced at lower altitudes and in plains. Forest carbon sinks decrease by 12,034 tons within a 0-20 km radius, causing an average economic loss of $1.81 million per wind farm. Our findings underscore the balanced mitigation strategies for renewable energy transition when transiting from fossil fuels.

Comparative evaluation of the fecal microbiota of adult hybrid pigs and Tibetan pigs, and dynamic changes in the fecal microbiota of hybrid pigs

The breed of pig can affect the diversity and composition of fecal microbiota, but there is a lack of research on the fecal microbiota of hybrid pigs. In this study, feces samples from Chuanxiang black pigs (a hybrid of Tibetan and Duroc pigs) aged 3 days (n = 24), 70 days (n = 31), 10 months (n = 13) and 2 years (n = 30) and Tibetan pigs aged 10 months (n = 14) and 2 years (n = 15) were collected and sequenced by 16S rRNA gene sequencing technology. We also measured the weight of all the tested pigs and found that the 10-month-old and two-year-old Chuanxiang black pigs weighed about three times the weight of Tibetan pigs of the same age. After comparing the genus-level microbiota composition of Tibetan pigs and Chuanxiang black pigs at 10 months and two years of age, we found that Treponema and Streptococcus were the two most abundant bacteria in Chuanxiang black pigs, while Treponema and Chirstensenellaceae_R.7_group were the two most abundant bacteria in Tibetan pigs. Prediction of microbial community function in adult Chuanxiang black pigs and Tibetan pigs showed changes in nutrient absorption, disease resistance, and coarse feeding tolerance. In addition, we also studied the changes in fecal microbiota in Chuanxiang black pigs at 3 days, 70 days, 10 months, and 2 years of age. We found that the ecologically dominant bacteria in fecal microbiota of Chuanxiang black pigs changed across developmental stages. For example, the highest relative abundance of 70-day-old Chuanxiang black pigs at the genus level was Prevotella. We identified specific microbiota with high abundance at different ages for Chuanxiang black pigs, and revealed that the potential functions of these specific microbiota were related to the dominant phenotype such as fast growth rate and strong disease resistance. Our findings help to expand the understanding of the fecal microbiota of hybrid pigs and provide a reference for future breeding and management of hybrid pigs.

The Prevalence of Behavioural Symptoms and Psychiatric Disorders in Hadza Children

The worldwide pooled prevalence of psychiatric disorders in children is 13.4%. Studying the prevalence of childhood psychiatric disorders across radically different economic systems and social structures could indicate universal factors leading to their development. The prevalence of childhood psychiatric disorders in a mixed-subsistence foraging society has not been studied. The Strengths and Difficulties Questionnaire and the Development and Well-Being Assessment were used to compare the prevalence of behavioural symptoms and psychiatric disorders in Hadza children aged 5-16 years (n = 113) to a nationally representative sample from England (n = 18,029) using a cross-sectional study design. Emotional problems, conduct problems and hyperactivity were lower in the Hadza children. Prosocial behaviour and peer problems were higher in Hadza children. 3.6% of Hadza children met the criteria for a psychiatric disorder compared to 11.8% of English children. All psychiatric disorders in Hadza children were co-morbid with autism spectrum disorder. No child from the Hadza group met the criteria for an emotional, behaviour or eating disorder. Further work should study the factors which lead to the different prevalence of psychiatric disorders in Hadza children.

Ancient dental calculus reveals oral microbiome shifts associated with lifestyle and disease in Great Britain

The prevalence of chronic, non-communicable diseases has risen sharply in recent decades, especially in industrialized countries. While several studies implicate the microbiome in this trend, few have examined the evolutionary history of industrialized microbiomes. Here we sampled 235 ancient dental calculus samples from individuals living in Great Britain (∼2200 BCE to 1853 CE), including 127 well-contextualized London adults. We reconstructed their microbial history spanning the transition to industrialization. After controlling for oral geography and technical biases, we identified multiple oral microbial communities that coexisted in Britain for millennia, including a community associated with Methanobrevibacter, an anaerobic Archaea not commonly prevalent in the oral microbiome of modern industrialized societies. Calculus analysis suggests that oral hygiene contributed to oral microbiome composition, while microbial functions reflected past differences in diet, specifically in dairy and carbohydrate consumption. In London samples, Methanobrevibacter-associated microbial communities are linked with skeletal markers of systemic diseases (for example, periostitis and joint pathologies), and their disappearance is consistent with temporal shifts, including the arrival of the Second Plague Pandemic. This suggests pre-industrialized microbiomes were more diverse than previously recognized, enhancing our understanding of chronic, non-communicable disease origins in industrialized populations.

Dietary supplementation with 1-kestose induces altered locomotor activity and increased striatal dopamine levels with a change in gut microbiota in male mice

1-Kestose (KES), a dietary fiber and prebiotic carbohydrate, benefits various physiological functions. This study aimed to examine whether diets supplemented with KES over three consecutive generations could significantly affect some host physiological aspects, including behavioral phenotypes and gut microbial ecology. Mice that received KES-supplemented diets for three generations demonstrated increased activity compared with those fed diets lacking KES. Furthermore, the KES group showed increased striatal dopamine (DA) and serotonin (5-HT) levels. The observed increase in DA levels within the striatum was positively correlated with locomotor activity in the KES group but not in the control (CON) group. The α-diversities were significantly lower in the KES group compared to the CON group. The three-dimensional principal coordinate analysis revealed a substantial distinction between the KES and CON groups across each generation. At the genus level, most gut microbiota genera exhibited lower abundances in the KES group than in the CON group, except for Bifidobacteria and Akkermansia. Spearman's rank-order analysis indicated significant negative correlations between the striatal DA levels and α-diversity values. These findings suggest that prolonged supplementation with KES may stimulate increased locomotor activity along with elevated striatal DA levels, which are potentially associated with KES-induced alterations in the gut microbiota.

Gut microbiomes of agropastoral children from the Adadle region of Ethiopia reflect their unique dietary habits

The composition and function of the intestinal microbiota are major determinants of human health and are strongly influenced by diet, antibiotic treatment, lifestyle and geography. Nevertheless, we currently have only little data on microbiomes of non-westernized communities. We assess the stool microbiota composition in 59 children aged 2-5 years from the Adadle district of Ethiopia, Somali Regional State. Here, milk and starch-rich food are predominant components of the local diet, where the inhabitants live a remote, traditional agropastoral lifestyle. Microbiota composition, function and the resistome were characterized by both 16S rRNA gene amplicon and shotgun metagenomic sequencing and compared to 1471 publicly available datasets from children living in traditional, transitional, and industrial communities with different subsistence strategies. Samples from the Adadle district are low in Bacteroidaceae, and Prevotellaceae, the main bacterial representatives in the feces of children living in industrialized and non-industrialized communities, respectively. In contrast, they had a higher relative abundance in Streptococcaceae, Bifidobacteriaceae and Erysipelatoclostridiaceae. Further, genes involved in degradation pathways of lactose, D-galactose and simple carbohydrates were enriched. Overall, our study revealed a unique composition of the fecal microbiota of these agropastoral children, highlighting the need to further characterize the fecal bacterial composition of human populations living different lifestyles.

Human microbiota dysbiosis after SARS-CoV-2 infection have the potential to predict disease prognosis

BACKGROUND

The studies on SARS-CoV-2 and human microbiota have yielded inconsistent results regarding microbiota α-diversity and key microbiota. To address these issues and explore the predictive ability of human microbiota for the prognosis of SARS-CoV-2 infection, we conducted a reanalysis of existing studies.

METHODS

We reviewed the existing studies on SARS-CoV-2 and human microbiota in the Pubmed and Bioproject databases (from inception through October 29, 2021) and extracted the available raw 16S rRNA sequencing data of human microbiota. Firstly, we used meta-analysis and bioinformatics methods to reanalyze the raw data and evaluate the impact of SARS-CoV-2 on human microbial α-diversity. Secondly, machine learning (ML) was employed to assess the ability of microbiota to predict the prognosis of SARS-CoV-2 infection. Finally, we aimed to identify the key microbiota associated with SARS-CoV-2 infection.

RESULTS

A total of 20 studies related to SARS-CoV-2 and human microbiota were included, involving gut (n = 9), respiratory (n = 11), oral (n = 3), and skin (n = 1) microbiota. Meta-analysis showed that in gut studies, when limiting factors were studies ruled out the effect of antibiotics, cross-sectional and case-control studies, Chinese studies, American studies, and Illumina MiSeq sequencing studies, SARS-CoV-2 infection was associated with down-regulation of microbiota α-diversity (P < 0.05). In respiratory studies, SARS-CoV-2 infection was associated with down-regulation of α-diversity when the limiting factor was V4 sequencing region (P < 0.05). Additionally, the α-diversity of skin microbiota was down-regulated at multiple time points following SARS-CoV-2 infection (P < 0.05). However, no significant difference in oral microbiota α-diversity was observed after SARS-CoV-2 infection. ML models based on baseline respiratory (oropharynx) microbiota profiles exhibited the ability to predict outcomes (survival and death, Random Forest, AUC = 0.847, Sensitivity = 0.833, Specificity = 0.750) after SARS-CoV-2 infection. The shared differential Prevotella and Streptococcus in the gut, respiratory tract, and oral cavity was associated with the severity and recovery of SARS-CoV-2 infection.

CONCLUSIONS

SARS-CoV-2 infection was related to the down-regulation of α-diversity in the human gut and respiratory microbiota. The respiratory microbiota had the potential to predict the prognosis of individuals infected with SARS-CoV-2. Prevotella and Streptococcus might be key microbiota in SARS-CoV-2 infection.