Identification of trypsin-degrading commensals in the large intestine

Leveraging Gastrointestinal Microbiota‒Host Co-oscillation Patterns for Improving Nitrogen Utilization Efficiency in Ruminants: A Review

Improving nitrogen utilization efficiency in ruminant livestock is vital for feeding a growing global population and lowering environmental pollution. The rumen and intestine harbor distinct epithelial structures and biogeographically stratified microbiota, and their co-oscillation assemblage patterns fulfill the pivotal role of metabolizing dietary nitrogen into bioavailable nutrients in ruminants. There is cursory evidence to suggest that an increased understanding of the spatial gastrointestinal microbiota‒host interactions will aid in the development of nutritional strategies to improve nitrogen utilization efficiency. In this review, we first explore the current knowledge on the processes of protein degradation, microbial protein synthesis, and urea nitrogen salvage in ruminal microorganisms and the epithelium. Second, we summarize the mechanisms of microbiota‒host interplay with regard to the amino acid utilization process in the intestine. Finally, we discuss the most pertinent and promising manipulation strategies that have emerged to balance food security and environmental impacts. In this review, we highlight the significance of leveraging gastrointestinal microbiota‒host co-oscillation patterns to improve nitrogen utilization efficiency, and put forward perspectives for future research opportunities that precisely target this coordinated interplay in the nitrogen metabolic network.

Sex differences in the association between long-term ambient particulate air pollution and the intestinal microbiome composition of children

The intestinal microbiome is essential for gastrointestinal and overall health, yet its response to air pollution in children remains underexplored. In a study involving 412 young children from the ENVIRONAGE cohort, stool samples were analysed via Illumina Miseq sequencing to assess microbiome alpha diversity (observed richness, species evenness, and Shannon diversity) and composition. Exposure to previous year particulate air pollution (black carbon, PM2.5, coarse PM, and PM10) was modeled using high-resolution spatial-temporal interpolation models. Multiple linear regression models were adjusted for a priori selected covariables and stratified by sex. Furthermore, we performed a differential relative abundance analysis at family and genus level, while accounting for the same covariables. Statistically significant effect modification by sex was apparent for several intestinal alpha diversity indices and air pollutants. In boys, we observed negative associations between particulate air pollution exposure and intestinal microbiome richness (estimates ranging from -5.55 to -9.06 per interquartile range (IQR) increase in particulate air pollution exposure) and Shannon diversity (estimates ranging from -0.058 to -0.095 per IQR increase). Differently, in girls non-significant positive associations were observed with species evenness (estimates ranging from 0.019 to 0.020 per IQR increase) and Shannon diversity (estimate 0.065 per IQR increase in black carbon). After multiple testing correction, we reported several bacterial families and genera (Streptococcaceae, Clostridiales Incertae Sedis XIII, Coriobacteriaceae, Streptococcus, and Paraprevotella) to be oppositely associated with particulate air pollution exposure in boys and girls. Our findings show a sex-dependent association between particulate air pollution exposure and intestinal microbiome composition, highlighting boys as potentially more vulnerable to diversity loss associated with childhood exposure to particulate pollution.

Alteration of salivary Streptococcus is associated with statin therapy in older adults: a cohort study

Background

Salivary microbiome alterations are associated with chronic diseases, such as cardiovascular disease, diabetes, and dementia. These chronic diseases often coexist in older adults, leading to polypharmacy. This situation complicates the relationship between systemic diseases and salivary microbiome dysbiosis. Previous studies have demonstrated the association of the human gut microbiome with common prescription drug use, including polypharmacy. However, a comprehensive analysis of the salivary microbiome and prescription drugs is yet to be conducted in older adults. Therefore, in this study, we performed a multivariate analysis to investigate the relationship between salivary microbiomes and host variables, including prescribed drugs, cognitive function, and oral health, in Japanese older adults with different disease backgrounds.

Methods

We enrolled non-hospitalised 82 older adults aged ≥70 years from a Japanese village community, and collected metadata, including age, sex, body mass index, cognitive function, oral health, alcohol consumption, smoking, and common prescription drug information. We performed multivariate analyses and functional predictions on the salivary microbiome based on 16S ribosomal RNA gene amplicon sequencing, including the metadata as potential confounders.

Results

We observed a relationship between the human salivary microbiome and prescribed drug use in Japanese older adults with a heterogeneous background of comorbidities. The effects of several prescribed drugs, such as statins, proton pump inhibitors, and transporter/symporter inhibitors, on the salivary microbiome diversity were more prominent than those of host variables, including age, sex, and oral health. Notably, statin use was strongly correlated with a decrease in the Streptococcus abundance. Furthermore, statin intensity and obesity may be associated with altering the salivary microbiome, including functional predictions for vitamin biosynthesis and purine nucleotide degradation pathways in statin users.

Conclusion

Our multivariate analysis, adjusted for prescribed drug use and non-use, revealed the drug-specific alteration of salivary microbiome composition in Japanese older adults with comorbidities. To our knowledge, this study is the first to described the association of common prescription drug use with salivary microbiome alterations in older adults. Our findings indicated that prescribed drug use is a key factor in understanding the link between salivary microbiome changes and systemic diseases in older adults.

WITHDRAWN: Comparative metatranscriptome analysis in gut reveals insignificant host or microbiota changes in SARS-related coronavirus naturally infected bats

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Novel insights into the genetic architecture and mechanisms of host/microbiome interactions from a multi-cohort analysis of outbred laboratory rats

The intestinal microbiome influences health and disease. Its composition is affected by host genetics and environmental exposures. Understanding host genetic effects is critical but challenging in humans, due to the difficulty of detecting, mapping and interpreting them. To address this, we analysed host genetic effects in four cohorts of outbred laboratory rats exposed to distinct but controlled environments. We found that polygenic host genetic effects were consistent across environments. We identified three replicated microbiome-associated loci. One involved a sialyltransferase gene and Paraprevotella and we found a similar association, between ST6GAL1 and Paraprevotella, in a human cohort. Given Paraprevotella's known immunity-potentiating functions, this suggests ST6GAL1's effects on IgA nephropathy and COVID-19 breakthrough infections may be mediated by Paraprevotella. Moreover, we found evidence of indirect genetic effects on microbiome phenotypes, which substantially increased their total genetic variance. Finally, we identified a novel mechanism whereby indirect genetic effects can contribute to "missing heritability".

Integrated microbiome and metabolome analysis reveals altered gut microbial communities and metabolite profiles in dairy cows with subclinical mastitis

BACKGROUND

Dairy cow mastitis is a common and prevalent disease arose by various complicated pathogeny, which poses serious threat to the health of cows, safety of dairy product and economic benefits for pastures. Due to the high stealthiness and long incubation period, subclinical mastitis (SM) of cows causes enormous economic losses. Besides the infection by exogenous pathogenic microorganisms, previous studies demonstrated that gastrointestinal microbial dysbiosis is one of the crucial causes for occurrence and development of mastitis based on the theory of entero-mammary axis. Whereas, limited researches have been conducted on potential pathological metabolic mechanisms underlying the relationship between gut microbiota and SM in cows.

RESULTS

The differences in blood parameters, gut microbiome, plasma and fecal metabolome between healthy and SM cows were compared by performing 16 S rDNA sequencing and non-targeted metabolomic analysis in the current study. The content of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and activity of catalase (CAT), total antioxidant capacity(T-AOC) were significantly decreased, while malondialdehyde (MDA) concentration was dramatically increased in serum of SM cows in comparison with healthy cows. The gut of cows with SM harbored more abundant Cyanobacteria, Proteobacteria, Succinivibrio and Lactobacillus_iners. Moreover, the abundance of Paraprevotella, Coprococcus, Succiniclasticum, Desulfovibrio and Bifidobacterium_pseudolongum were observably reduced in the gut of SM cows. Furthermore, higher abundance of pro-inflammatory metabolites were observed in feces (9(S)-HPODE, 25-hydroxycholesterol, dodecanedioic acid, etc.) and plasma (9-hydroxy-10,12-octadecadienoic acid, 13,14-dihydro PGF1α, 5,6-dehydro arachidonic acid, myristic acid, histamine, etc.) of SM cows. The abundance of certain metabolites with anti-inflammatory and antioxidant properties (mandelic acid, gamma-tocotrienol, deoxycholic acid, etc.) were notably decreased in feces or plasma of cows with SM.

CONCLUSIONS

The intestinal microbial composition and metabolic profiles of healthy and SM cows were significantly distinct, that were characterized by decreased abundance of intestinal symbiotic bacteria, potential probiotics and anti-inflammatory, antioxidant compounds, along with increased abundance of potential pro-inflammatory bacteria, lipid metabolites, and the occurrence of oxidative stress in cows suffered from SM. The results of this study further enriched our understanding of the correlations between gut microbiota and metabolic profiles and SM, which provided insight into the formulation of management strategies for SM in cows.

Urinary Metabolomics of Plastic Manufacturing Workers: A Pilot Study

The plastic manufacturing industry has a crucial role in the global economy with a significant impact in a wide range of fields. The chemical risk to which workers are potentially exposed is difficult to characterize and strictly related to both the products and processes adopted. Among the chemicals used, we can cite styrene, phenol, butadiene and phthalates, but nano- and microplastic particles can also be released in the work environment. In this pilot study, we present for the first time an NMR-based metabolomic approach for assessing urinary profiles of workers employed in a plastic manufacturing company. Urine samples from twelve workers and thirteen healthy volunteers were collected and analyzed by NMR spectroscopy. Forty-six urinary metabolites belonging to different chemical classes were univocally identified and quantified. The dataset so obtained was then subjected to multivariate statistical analysis to characterize each profile and highlight any differences. An alteration in some metabolites involved in several pathways, such as amino acid metabolism and NAD metabolism, was found, and a strong impact on gut microflora was also speculated. Ultimately, our work has the objective of adding a tile to the knowledge of biological effects possibly related to occupational exposure even if it is below the threshold limit values.

Fecal Proteolytic Bacteria and Staphylococcal Superantigens Are Associated With Abdominal Pain Severity in Irritable Bowel Syndrome

INTRODUCTION

Changes in the composition of the gut microbiota have been associated with the development of irritable bowel syndrome (IBS). However, to what extent specific bacterial species relate to clinical symptoms remains poorly characterized. We investigated the clinical relevance of bacterial species linked with increased proteolytic activity, histamine production, and superantigen (SAg) production in patients with IBS.

METHODS

Fecal (n = 309) and nasal (n = 214) samples were collected from patients with IBS and healthy volunteers (HV). Clinical symptoms and gut transit time were evaluated. Bacterial abundance in feces and nasal swabs as well as fecal trypsin-like activity were assessed.

RESULTS

The percentage of fecal samples containing Staphylococcus aureus was significantly higher in IBS compared with HV. Forty-nine percent of S. aureus -positive fecal samples from patients with IBS were also positive for SAgs, compared with 12% of HV. Patients with IBS and positive fecal SAg-producing S. aureus reported higher pain scores than those without S. aureus . Moreover, increased fecal proteolytic activity was associated with abdominal pain. Fecal abundance of Paraprevotella clara and Alistipes putredinis was significantly decreased in IBS, particularly in samples with higher proteolytic activity. Patients with lower Alistipes putredinis or Faecalibacterium prausnitzii abundance reported more severe abdominal pain.

DISCUSSION

In keeping with our preclinical findings, we show that increased presence of SAg-producing S. aureus in fecal samples of patients with IBS is associated with increased levels of abdominal pain. We also show that increased fecal proteolytic activity is associated with increased abdominal pain in patients with IBS.

Comparative analysis of amino acid auxotrophies and peptidase profiles in non-dysbiotic and dysbiotic small intestinal microbiomes

Small Intestinal Bacterial Overgrowth (SIBO) is linked to various diseases and has been associated with altered serum amino acid levels. However, the direct role of the gut microbiome in these changes remains unconfirmed. This study employs genome-scale metabolic modeling to predict amino acid auxotrophy and peptidase gene profiles in the small intestinal microbiomes of SIBO and non-SIBO subjects. Auxotrophy and peptidase gene profiles were further examined in the large intestinal microbiome under non-dysbiotic conditions to assess their similarity to the microbial SIBO profile. Our analysis revealed that the abundance of auxotrophic bacteria is higher in the microbiota of the small intestine than in the large intestine in non-dysbiotic controls. In patients with SIBO, the abundance of auxotrophies in the small intestine decreased compared to non-SIBO subjects. Peptidase gene profiles in non-dysbiotic individuals were distinct between small and large intestinal microbiomes, with fewer extracellular peptidase genes in small intestine microbiomes. In SIBO, extracellular peptidase genes increased compared to non-SIBO subjects. Further, there were more significant associations between the abundance of auxotrophies and peptidase genes in microbiomes of the small intestine compared to the large intestine. In conclusion, the auxotrophy and peptidase gene profiles of the small and large intestinal microbiomes were distinct. In SIBO, the small intestinal microbiome shifts towards a metabolic state resembling that of the large intestine, particularly in its increased abundance of extracellular peptidase genes. This highlights the potential of genome-scale metabolic modeling in identifying metabolic disruptions associated with SIBO, which could inform the development of targeted interventions.

Gut microbiome-derived bacterial extracellular vesicles in patients with solid tumours

INTRODUCTION

Gut microbiome-derived nanoparticles, known as bacterial extracellular vesicles (bEVs), have garnered interest as promising tools for studying the link between the gut microbiome and human health. The diverse composition of bEVs, including their proteins, mRNAs, metabolites, and lipids, makes them useful for investigating diseases such as cancer. However, conventional approaches for studying gut microbiome composition alone may not be accurate in deciphering host-gut microbiome communication. In clinical microbiome research, there is a gap in the knowledge on the role of bEVs in solid tumor patients.

OBJECTIVES

Analyzing the functionality of bEVs using (meta)genomics and proteomics could highlight the unique aspects of host-gut microbiome interactions in solid tumor patients. Therefore, we performed a comparative analysis of the proteome and microbiota composition of gut microbiome-derived bEVs isolated from patients with solid tumors and healthy controls.

METHODS

After isolating bEVs from the feces of solid tumor patients and healthy controls, we performed spectrometry analysis of their proteomes and next-generation sequencing (NGS) of the 16S gene. We also investigated the gut microbiomes of feces from patients and controls using 16S sequencing and used machine learning to classify the samples into patients and controls based on their bEVs and fecal microbiomes.

RESULTS

Solid tumor patients showed decreased microbiota richness and diversity in both the bEVs and feces. However, the bEV proteomes were more diverse in patients than in the controls and were enriched with proteins associated with the metabolism of amino acids and carbohydrates, nucleotide binding, and oxidoreductase activity. Metadata classification of samples was more accurate using fecal bEVs (100%) compared with fecal samples (93%).

CONCLUSION

Our findings suggest that bEVs are unique functional entities. There is a need to explore bEVs together with conventional gut microbiome analysis in functional cancer research to decipher the potential of bEVs as cancer diagnostic or therapeutic biomarkers.

A membrane-associated conveyor belt controls the rotational direction of the bacterial type 9 secretion system

Many bacteria utilize the type 9 secretion system (T9SS) for gliding motility, surface colonization, and pathogenesis. This dual-function motor supports both gliding motility and protein secretion, where rotation of the T9SS plays a central role. Fueled by the energy of the stored proton motive force and transmitted through the torque of membrane-anchored stator units, the rotary T9SS propels an adhesin-coated conveyor belt along the bacterial outer membrane like a molecular snowmobile, thereby enabling gliding motion. However, the mechanisms controlling the rotational direction and gliding motility of T9SS remain elusive. Shedding light on this mechanism, we find that in the gliding bacterium Flavobacterium johnsoniae , deletion of the C-terminus of a conveyor belt protein GldJ controls, and in fact, reverses the rotational direction of T9SS from counterclockwise to clockwise thus suggesting that the interface between the conveyor belt protein GldJ and the T9SS ring protein GldK plays an important role in controlling the directionality of T9SS. Combined with MD simulation of the T9SS stator units GldLM, we suggest a 'tri-component gearset' model where the conveyor belt controls the rotational direction of its driver, the T9SS, thus providing adaptive sensory feedback to influence the motility of the gliding bacterium.

The causal relationship of cigarette smoking to metabolic disease risk and the possible mediating role of gut microbiota

BACKGROUND

Cigarette smoking is a leading cause of preventable death worldwide, with its associated diseases and conditions. Emerging evidence suggests that cigarette smoking contributes to a range of pathological metabolic injuries, including diabetes and nonalcoholic fatty liver disease (NAFLD). The impact of gut microbiota on metabolic health and diseases has been observed, but the causality remains uncertain.

OBJECTIVE

To confirm the causal relationship between cigarette smoking and metabolic diseases, and to investigate the possible mediating effect of gut microbiota on these connections.

METHODS

The relationships among cigarette smoking, metabolic diseases, and the gut microbiome were analyzed by Univariate Mendelian randomization (UVMR). Furthermore, to mitigate the impact of confounding factors, adjusted models were conducted via the multivariate Mendelian randomization (MVMR) method, aiming to improve the accuracy of prediction. Ultimately, the study evaluated the effect of the intermediary factor, gut microbiome, on the relationship between cigarette smoke and metabolic diseases.

RESULTS

The phenomenon that a causal relationship between cigarette smoke (249752 individuals) and gut microbiota (7738 individuals), diabetes (406831 individuals), NAFLD (377998 individuals), hypercholesterolaemia (463010 individuals), and obesity (463010 individuals) was observed using UVMR. In the MVMR model, the genetic connection between cigarette smoking, gut microbiota, and type 2 diabetes remained significant. Of note, paraprevotella_clara served an important mediating role in the type 2 diabetes associated with cigarette smoke.

CONCLUSION

This work offered genetic evidence linking cigarette smoke to metabolic diseases, suggesting that the gut microbiota, particularly paraprevotella_clara, might be a crucial mediator in the development of type 2 diabetes caused by cigarette smoke. Our future studies should consider conducting other ethnic groups MR analyses, particularly with larger sample sizes. Still, more in vivo and in vitro work should be carried out to validate the precise effect and molecular mechanisms of the gut microbiome.

Identification of nanaomycin A and its analogs by a newly established screening method for functional inhibitors of the type IX secretion system in Porphyromonas gingivalis

Porphyromonas gingivalis, a Gram-negative anaerobic bacterium, is a key pathogen in chronic periodontitis. P. gingivalis has a type IX secretion system (T9SS) that secretes highly hydrolytic proteinases called gingipains for obtaining peptides as an energy source. Although most T9SS-related proteins have been identified, no specific inhibitor of T9SS has been reported. To screen T9SS inhibitors, we focused on and characterized a minimal liquid medium called mC medium that contains milk casein as the sole protein source. We found that P. gingivalis wild-type strain ATCC 33277 caused cloudiness of mC medium without growth. In mC medium, an alkylating agent, iodoacetamide (IAM) that is an inhibitor of gingipains, and a protonophore, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) that dissipates the proton motive force required for T9SS-mediated secretion, clearly inhibited the increase in turbidity. Moreover, neither the gingipain-null mutant nor the T9SS-deficient mutant caused mC medium cloudiness, suggesting that mC medium cloudiness is dependent on gingipain activity and T9SS. These results indicated that mC medium can be used to assess P. gingivalis gingipain activity and its functional T9SS. Using an assay system with mC medium, we discovered that OM-173αA and OM-173βA in the Ōmura Natural Compound Library and nanaomycin A were probable T9SS inhibitors. The compounds need to be further investigated as tools for analyzing T9SS and as potential therapeutic agents for periodontal disease.

Does Gut Microbiome have an Effect on Wilson's Disease Phenotype?

Wilson's Disease (WD), a genetic metabolic disorder, is characterized by the accumulation of copper in the liver and brain, resulting in a range of clinical symptoms. The clinical manifestations of WD vary widely. The present study introduces the distinctive features of intestinal microbiota in Chinese patients with WD, presenting diverse clinical symptoms. It shows a reduction in the diversity of gut microbiota among patients with hepatic symptoms associated with WD, particularly in the genus responsible for SCFAs production. It demonstrates an increase in the Haemophilus microorganism. This study may offer novel insights for further investigation into the mechanisms underlying the occurrence, development, and treatment of WD subtypes.

Carotenoids from Halophilic Archaea: A Novel Approach to Improve Egg Quality and Cecal Microbiota in Laying Hens

Carotenoids from different sources have different structures and functions, and their dietary components benefit the health of various organisms. The effects of halophilic Archaea-derived C50 carotenoids on poultry egg quality and gut microbiota remain largely unexplored. In this study, we isolated a carotenoid-secreting strain of Halalkalicoccus paucihalophilus, TRM89021, from the Pamir Plateau. We characterized the carotenoid pigments produced by this strain; the major components were bacterioruberin and its derivatives. The effects of these carotenoids on the egg quality and cecal microbiota composition of hens were investigated. Compared to the basal diet group (BDG), supplementation with carotenoids in the carotenoids-supplemented diet group (CDG) resulted in significantly lower a* and b* scores at week 5 and lower b* scores and Haugh units at week 2, while egg strength and weight were higher. CDG also showed increased yolk antioxidant capacity, higher glutathione peroxidase levels, and significantly lower catalase levels (p < 0.05). Plasma analysis revealed elevated total bilirubin and aspartate aminotransferase levels, along with reduced inorganic phosphorus levels in the CDG (p < 0.05). No significant differences in cecal microbiota diversity were observed between the groups at any taxonomic level. This result suggests that halophilic archaea-derived carotenoids have the potential to be used as natural feed supplements to improve egg quality. Our study provides a theoretical basis for applying archaea-derived carotenoids in poultry diets.

Dietary metabolizable energy and crude protein levels affect Taihe silky fowl growth performance, meat quality, and cecal microbiota during fattening

The effects of dietary metabolizable energy (ME) and crude protein (CP) on the growth performance, meat quality, and cecal microbiota of Taihe Silky Fowl (TSF) during fattening were investigated. In total, 900 twelve-week-old female fowl were randomly allocated to 9 treatments (5 replicates per group, 20 fowl per replicate), and were fed a 3 × 3 factorial arrangement of treatments diets (ME: 11.30, 11.93, or 12.56 MJ/kg; CP: 15%, 16%, or 17%). As ME increased, the average daily feed intake (ADFI, P<0.001), feed conversion ratio (FCR, P<0.001), pectoral and thigh shear forces (P<0.05), pectoral and thigh muscle fiber diameter (P<0.001) decreased significantly, while muscle fiber density increased (P<0.001). Pectoral muscle fiber diameter was lower and muscle fiber density higher at 16% CP than 15% or 17%. As ME increased, pectoral crude fat content increased significantly (P = 0.007). Pectoral crude protein, total amino acid (TAA), and essential amino acid (EAA) content were higher at 15% dietary CP than 16% or 17%. As ME increased, pectoral inosine monophosphate (IMP, P = 0.006), uridylic monophosphate (UMP, P = 0.003), guanylic monophosphate (GMP, P = 0.009), and adenosine monophosphate (AMP, P <0.001) decreased significantly, while hypoxanthine riboside (HxR, P = 0.045) increased. As dietary CP increased, IMP (P = 0.019), AMP (P <0.001), and HxR (P = 0.024) increased significantly. Cecal microbiota composition varied with dietary ME: 12.56 MJ/kg ME increased the abundance of Bifidobacteriaceae, and 15% CP increased that of Paraprevotella. These findings suggest that 12.56 MJ/kg dietary ME and 15% CP can enhance growth performance, improve meat quality by reducing shear force, enhancing flavor and nutritional value, and benefit for intestinal microbiota in fattening TSF.

Multi-Omics Reveal the Improvements of Nutrient Digestion, Absorption, and Metabolism and Intestinal Function via GABA Supplementation in Weanling Piglets

The nonprotein amino acid γ-aminobutyric acid (GABA) can enhance intestinal function in piglets; however, the mechanisms involved are not yet fully understood. To explore the effects of GABA and its underlying mechanisms, weanling piglets were randomly assigned to three groups, receiving either a basal diet or a basal diet supplemented with GABA (80 mg/kg or 120 mg/kg). The results demonstrated that dietary GABA improved growth performance and reduced diarrhea incidence (p < 0.05). Additionally, GABA supplementation decreased the serum and intestinal levels of pro-inflammatory cytokines (p < 0.05), and improved intestinal morphology. Multi-omics analyses were employed to explore the alterations caused by GABA supplementation and elucidate the related mechanisms. Microbiota profiling revealed improved beta-diversity and changes in the composition of ileal bacteria and fungi. Amino acid metabolism, lipid metabolism, and digestive processes were primarily enriched in the GABA group according to metabolomics analysis. A transcriptome analysis showed significant enrichment in ion transmembrane transport and nutrition absorption and digestion pathways in the ileum. Furthermore, increased lipase and trypsin activity, along with the elevated expression of tight junction proteins confirmed the beneficial effects of GABA on intestinal nutrient metabolism and barrier function. In conclusion, dietary 80 mg/kg GABA supplementation improved nutrient digestion and absorption and intestinal function in weanling piglets.

Inducible, but not constitutive, pancreatic REG/Reg isoforms are regulated by intestinal microbiota and pancreatic diseases

The REG / Reg gene locus encodes for a conserved family of potent antimicrobial but also pancreatitis-associated proteins. Here we investigated whether REG/Reg family members differ in their baseline expression levels and abilities to be regulated in the pancreas and gut upon perturbations. We found, in human and mouse, pancreas and gut differed in REG / Reg isoform levels and preferences, with duodenum most resembling the pancreas. Pancreatic acinar cells and intestinal enterocytes were the dominant REG producers. Intestinal symbiotic microbes regulated the expression of the same, select Reg members in gut and pancreas. These Reg members had the most STAT3-binding sites close to the transcription start sites and were partially IL-22 dependent. We thus categorized them as "inducible" and others as "constitutive". Indeed, also in models of pancreatic-ductal adenocarcinoma and pancreatitis, only inducible Reg members were upregulated in pancreas. While intestinal Reg expression remained unchanged upon pancreatic perturbation, pancreatitis altered the microbial composition of the duodenum and feces shortly after disease onset. Our study reveals differential usage and regulation of REG / Reg isoforms as a mechanism for tissue-specific innate immunity, highlights the intimate connection of pancreas and duodenum, and implies a gut-to-pancreas communication axis resulting in a coordinated Reg response.

Comparative analysis of COVID-19 responses in Japan and Africa: diet, phytochemicals, vitamin D, and gut microbiota in reducing mortality-A systematic review and meta-analysis

Background

As the novel coronavirus disease 2019 (COVID-19) pandemic subsides, the clinical sequelae are becoming more problematic. Interestingly, the statistical data indicate that Africa has experienced the lowest number of cases and deaths, with an unexpected phenomenon where the number of deaths from COVID-19 has not increased significantly. Several studies have investigated the relationship between diet and coronavirus. However, no systematic review/meta-analysis has conclusively linked diet (phytochemicals and vitamin D) and the gut microbiota in the context of COVID-19.

Methods

This study examined the responses to COVID-19 in Japan and Africa, formulating the following hypotheses: (1) a healthy diet is effective against COVID-19, (2) blood vitamin D levels are associated with COVID-19 mortality, and (3) COVID-19 is associated with the gut microbiota. To investigate these hypotheses, a keyword search and meta-analysis were conducted using PubMed, and each hypothesis was tested.

Results

This study found that a healthy diet, particularly rich in phytochemicals such as polyphenols and flavonoids, is effective against COVID-19. An association was detected between blood vitamin D levels and COVID-19 mortality. The gut microbiota was linked to COVID-19 and its amelioration. These findings may have significant implications for not only understanding COVID-19 but also future prevention of pneumonia.

A mouse protozoan boosts antigen-specific mucosal IgA responses in a specific lipid metabolism- and signaling-dependent manner

IgA antibodies play an important role in mucosal immunity. However, there is still no effective way to consistently boost mucosal IgA responses, and the factors influencing these responses are not fully understood. We observed that colonization with the murine intestinal symbiotic protozoan Tritrichomonas musculis (T.mu) boosted antigen-specific mucosal IgA responses in wild-type C57BL/6 mice. This enhancement was attributed to the accumulation of free arachidonic acid (ARA) in the intestinal lumen, which served as a signal to stimulate the production of antigen-specific mucosal IgA. When ARA was prevented from undergoing its downstream metabolic transformation using the 5-lipoxygenase inhibitor zileuton or by blocking its downstream biological signaling through genetic deletion of the Leukotriene B4 receptor 1 (Blt1), the T.mu-mediated enhancement of antigen-specific mucosal IgA production was suppressed. Moreover, both T.mu transfer and dietary supplementation of ARA augmented the efficacy of an oral vaccine against Salmonella infection, with this effect being dependent on Blt1. Our findings elucidate a tripartite circuit linking nutrients from the diet or intestinal microbiota, host lipid metabolism, and the mucosal humoral immune response.

The causal association between gut microbiota and postpartum depression: a two-sample Mendelian randomization study

Background

An escalating body of clinical trials and observational studies hints at a plausible link between gut flora and postpartum depression (PPD). The definitive causal dynamics between these two entities remain shrouded in ambiguity. Therefore, in this study, we employed the two-sample Mendelian randomization approach to ascertain the causal link between gut microbiota and PPD.

Methods

Summary-level GWAS data related to the human gut microbiota were obtained from the international consortium MiBioGen and the Dutch Microbiome Project (species). For PPD, GWAS data were derived from the FinnGen biobank, consisting 57,604 cases and 596,601 controls. The inverse variance weighted method (IVW) as the cornerstone of our analytical approach. Subsequent to this, a comprehensive suite of tests for pleiotropy and heterogeneity were conducted to ensure the reliability and robustness of our findings.

Results

We identified 12 bacterial taxa associated with the risk of PPD. Veillonellaceae, Ruminococcaceae UCG 011, Bifidobacterium adolescentis, Paraprevotella clara, Clostridium leptum, Eubacterium siraeum, Coprococcus catus exhibited an inversely associated with the risk of PPD. Alphaproteobacteria, Roseburia, FamilyXIIIAD3011group, Alistipes onderdonkii, Bilophila wadsworthia showed a positive correlation with the risk of PPD.

Limitations

The GWAS data derived from the MiBioGen consortium, DMP, and FinnGen consortium, may introduce selection bias. Moreover, the data primarily originates from European populations, hence extrapolating these results to diverse populations should be approached with caution. The etiological factors behind PPD remain enigmatic, alluding to the existence of potential undisclosed confounders.

Conclusion

Based on this MR analysis, we found a causal relationship between certain gut microbial communities and PPD. Future clinical studies can further explore the treatment of PPD through the combined use of microorganisms. This not only offers insights into the pathogenesis of PPD but also lays the foundation for utilizing gut microbiota as biotherapeutics in treating neurological disorders.

Weissella paramesenteroides NRIC1542 inhibits dextran sodium sulfate-induced colitis in mice through regulating gut microbiota and SIRT1/NF-κB signaling pathway

Inflammatory bowel disease (IBD) is a kind of recurrent inflammatory disorder of the intestinal tract. The purpose of this study was to investigate the effects of Weissella paramesenteroides NRIC1542 on colitis in mice. A colitis model was induced by adding 1.5% DSS to sterile distilled water for seven consecutive days. During this process, mice were administered different concentrations of W. paramesenteroides NRIC1542. Colitis was assessed by DAI, colon length and hematoxylin-eosin staining of colon sections. The expressions of NF-κB signaling proteins and the tight junction proteins ZO-1 and occludin were detected by western blotting, and the gut microbiota was analyzed by 16S rDNA. The results showed that W. paramesenteroides NRIC1542 significantly reduced the degree of pathological tissue damage and the levels of TNF-α and IL-1β in colonic tissue, inhibiting the NF-κB signaling pathway and increasing the expression of SIRT1, ZO-1 and occludin. In addition, W. paramesenteroides NRIC1542 can modulate the structure of the gut microbiota, characterized by increased relative abundance of Muribaculaceae_unclassified, Paraprevotella, Prevotellaceae_UCG_001 and Roseburia, and decrease the relative abundance of Akkermansia and Alloprevotella induced by DSS. The above results suggested that W. paramesenteroides NRIC1542 can protect against DSS-induced colitis in mice through anti-inflammatory, intestinal barrier maintenance and flora modulation.

Prebiotic characteristics of degraded polysaccharides from Acanthopanax senticosus polysaccharide on broilers gut microbiota based on in vitro digestion and fecal fermentation

This study aimed to evaluate the effect of low molecular weight Acanthopanax polysaccharides on simulated digestion, probiotics, and intestinal flora of broilers in vitro. The experiments were carried out by H2O2-Vc degradation of Acanthopanax polysaccharides, in vitro simulated digestion to evaluate the digestive performance of polysaccharides with different molecular weights, in vitro probiotic evaluation of the probiotic effect of polysaccharides on lactobacilli and bifidobacteria, in vitro anaerobic fermentation and high-throughput sequencing of 16S rRNA genes to study the impact of Acanthopanax polysaccharides on the intestinal flora of broilers, and the effect of Acanthopanax polysaccharides on the short-chain fatty acids of intestines were determined by GC-MS method. The results showed that the molecular weight of Acanthopanax polysaccharide (ASPS) was 9,543 Da, and the molecular weights of polysaccharides ASPS-1 and ASPS-2 were reduced to 4,288 Da and 3,822 Da after degradation, and the particle sizes, PDIs, and viscosities were also significantly decreased. ASPS-1 has anti-digestive properties and better in vitro probiotic properties. The addition of ASPS-1 regulates the structure of intestinal microorganisms by regulating fecalibacterium to produce short-chain fatty acids, promoting the colonization of beneficial bacteria such as fecalibacterium, paraprevotella and diminishing the prevalence of detrimental bacteria such as Fusobacteria. Interestingly the ASPS-1 group found higher levels of Paraprevotella, which degraded trypsin in the gut, reducing inflammation, acted as a gut protector, and was influential in increasing the levels of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and total SCFAs in the fermented feces. Therefore, the degraded ASPS-1 can better regulate the structure of intestinal flora and promote the production of SCFAs, creating possibilities for its use as a potential prebiotic, which is conducive to the intestinal health of poultry.

Polygonatum cyrtonema polysaccharides reshape the gut microbiota to ameliorate dextran sodium sulfate-induced ulcerative colitis in mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized inflammatory imbalance, intestinal epithelial mucosal damage, and dysbiosis of the gut microbiota. Polygonatum cyrtonema polysaccharides (PCPs) can regulate gut microbiota and inflammation. Here, the different doses of PCPs were administered to dextran sodium sulfate-induced UC mice, and the effects of the whole PCPs were compared with those of the fractionated fractions PCP-1 (19.9 kDa) and PCP-2 (71.6 and 4.2 kDa). Additionally, an antibiotic cocktail was administered to UC mice to deplete the gut microbiota, and PCPs were subsequently administered to elucidate the potential role of the gut microbiota in these mice. The results revealed that PCP treatment significantly optimized the lost weight and shortened colon, restored the balance of inflammation, mitigated oxidative stress, and restored intestinal epithelial mucosal damage. And, the PCPs exhibited superior efficacy in ameliorating these symptoms compared with PCP-1 and PCP-2. However, depletion of the gut microbiota diminished the therapeutic effects of PCPs in UC mice. Furthermore, fecal transplantation from PCP-treated UC mice to new UC-afflicted mice produced therapeutic effects similar to PCP treatment. So, PCPs significantly ameliorated the symptoms, inflammation, oxidative stress, and intestinal mucosal damage in UC mice, and gut microbiota partially mediated these effects.

Ecological, beneficial, and pathogenic functions of the Type 9 Secretion System

The recently discovered Type 9 Secretion System (T9SS) is present in bacteria of the Fibrobacteres-Bacteroidetes-Chlorobi superphylum, which are key constituents of diverse microbiomes. T9SS is instrumental in the extracellular secretion of over 270,000 proteins, including peptidases, sugar hydrolases, metal ion-binding proteins, and metalloenzymes. These proteins are essential for the interaction of bacteria with their environment. This mini-review explores the extensive array of proteins secreted by the T9SS. It highlights the diverse functions of these proteins, emphasizing their roles in pathogenesis, bacterial interactions, host colonization, and the overall health of the ecosystems inhabited by T9SS-containing bacteria.

Microbiota metabolism of intestinal amino acids impacts host nutrient homeostasis and physiology

The intestine and liver are thought to metabolize dietary nutrients and regulate host nutrient homeostasis. Here, we find that the gut microbiota also reshapes the host amino acid (aa) landscape via efficiently metabolizing intestinal aa. To identify the responsible microbes/genes, we developed a metabolomics-based assay to screen 104 commensals and identified candidates that efficiently utilize aa. Using genetics, we identified multiple responsible metabolic genes in phylogenetically diverse microbes. By colonizing germ-free mice with the wild-type strain and their isogenic mutant deficient in individual aa-metabolizing genes, we found that these genes regulate the availability of gut and circulatory aa. Notably, microbiota genes for branched-chain amino acids (BCAAs) and tryptophan metabolism indirectly affect host glucose homeostasis via peripheral serotonin. Collectively, at single-gene level, this work characterizes a microbiota-encoded metabolic activity that affects host nutrient homeostasis and provides a roadmap to interrogate microbiota-dependent activity to improve human health.

Butane Tetracarboxylic Acid Grafted on Polymeric Nanofibrous Aerogels for Highly Efficient Protein Absorption and Separation

Developing high-performance and low-cost protein purification materials is of great importance to meet the demands for highly purified proteins in biotechnological industries. Herein, a facile strategy was developed to design and construct high-efficiency protein absorption and separation media by combining aerogels' molding techniques and impregnation processes. Poly (ethylene-co-vinyl alcohol) (EVOH) nanofibrous aerogels (NFAs) were modified by grafting butane tetracarboxylic acid (BTCA) over them in situ. This modification was carried out using polyphosphoric acid as a catalyst. The resulting EVOH/BTCA NFAs exhibited favorable comprehensive properties. Benefiting from the highly interconnected porous structure, good underwater compressive properties, and abundant absorption ligands, the obtained EVOH/BTCA NFAs possessed a high static absorption capacity of 1082.13 mg/g to lysozyme and a short absorption equilibrium time of about 6 h. A high saturated dynamic absorption capacity for lysozyme (716.85 mg/g) was also realized solely by gravity. Furthermore, EVOH/BTCA NFAs displayed excellent reusability, good acid and alkaline resistance, and unique absorption selectivity performance. The successful synthesis of such aerogels can provide a potential candidate for next-generation protein absorbents for bio-separation and purification engineering.

Effects of dietary Artemisia annua supplementation on growth performance, antioxidant capacity, immune function, and gut microbiota of geese

This experiment aimed to study the effect of 1% Artemisia annua added to the diet on growth performance, antioxidant capacity, immunity and intestinal morphology, and gut microbiota of geese. Seventy-two 35-day-old male geese (Zi goose) with similar body weight were selected and randomly divided into 2 groups. Each treatment group of 36 geese was divided into 6 subgroups, each having 6 male geese. The experiment lasted for 21 d. Control group (CON) was fed a basal diet and the experimental group (AAL) was fed a basal diet + 1% Artemisia annua. BW, ADG, and ADFI of the AAL group increased (p < 0.05) and the FCR decreased (p < 0.05) compared with the CON group. The addition of Artemisia annua to the diet increased catalase (CAT), glutathione peroxidase (GSH-px), and superoxide dismutase (SOD) enzyme activities, increased total antioxidant capacity (T-AOC), and decreased malondialdehyde (MDA) content in serum and jejunum of geese (p < 0.05). Meanwhile, serum IgA, IgG, IgM, and lysozyme (LZM), increased at different time points in the AAL group compared to the CON group (p < 0.05), and decrease in the content of interferon-γ (IFN-γ) , IL-6 (p < 0.05), but no effect on complement C3 and C4. Morphological observation of the small intestine showed that the jejunal crypt depth was decreased in the AAL group (p < 0.05) while elevating the jejunal villus height/crypt depth (p < 0.05). 16S rRNA sequencing results showed the Artemisia annua increased the diversity of cecum microbiota, increasing the relative abundance of Bacteroides, Fecalibacterium, and Paraprevotella. In conclusion, the addition of 1% Artemisia annua to the diet could improve the growth performance, antioxidant and immune ability of geese, as well as improve the development of the jejunum intestinal tract of geese, and change the structure of the cecum microbiota, which had a positive effect on the growth and development of geese. Artemisia annua can be further developed as a feed additive.

Synthetic Communities of Gut Microbes for Basic Research and Translational Approaches in Animal Health and Nutrition

Microbes and animals have a symbiotic relationship that greatly influences nutrient uptake and animal health. This relationship can be studied using selections of microbes termed synthetic communities, or SynComs. SynComs are used in many different animal hosts, including agricultural animals, to investigate microbial interactions with nutrients and how these affect animal health. The most common host focuses for SynComs are currently mouse and human, from basic mechanistic research through to translational disease models and live biotherapeutic products (LBPs) as treatments. We discuss SynComs used in basic research models and findings that relate to human and animal health and nutrition. Translational use cases of SynComs are discussed, followed by LBPs, especially within the context of agriculture. SynComs still face challenges, such as standardization for reproducibility and contamination risks. However, the future of SynComs is hopeful, especially in the areas of genome-guided SynCom design and custom SynCom-based treatments.

Alterations in gut and genital microbiota associated with gynecological diseases: a systematic review and meta-analysis

BACKGROUND

Increasing number of studies have demonstrated certain patterns of microbial changes in gynecological diseases; however, the interaction between them remains unclear. To evaluate the consistency or specificity across multiple studies on different gynecological diseases and microbial alterations at different sites of the body (gut and genital tract), we conducted a systematic review and meta-analysis.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library up to December 5, 2022(PROSPERO: CRD42023400205). Eligible studies focused on gynecological diseases in adult women, applied next-generation sequencing on microbiome, and reported outcomes including alpha or beta diversity or relative abundance. The random-effects model on standardized mean difference (SMD) was conducted using the inverse-variance method for alpha diversity indices.

RESULTS

Of 3327 unique articles, 87 eligible studies were included. Significant decreases were found in gut microbiome of patients versus controls (observed species SMD=-0.35; 95%CI, -0.62 to -0.09; Shannon index SMD=-0.23; 95%CI, -0.40 to -0.06), whereas significant increases were observed in vaginal microbiome (Chao1 SMD = 1.15; 95%CI, 0.74 to 1.56; Shannon index SMD = 0.51; 95%CI, 0.16 to 0.86). Most studies of different diagnostic categories showed no significant differences in beta diversity. Disease specificity was observed, but almost all the changes were only replicated in three studies, except for the increased Aerococcus in bacterial vaginosis (BV). Patients with major gynecological diseases shared the enrichment of Prevotella and depletion of Lactobacillus, and an overlap in microbes was implied between BV, cervical intraepithelial neoplasia, and cervical cancer.

CONCLUSIONS

These findings demonstrated an association between alterations in gut and genital microbiota and gynecological diseases. The most observed results were shared alterations across diseases rather than disease-specific alterations. Therefore, further investigation is required to identify specific biomarkers for diagnosis and treatment in the future.

The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs

Drugs based on peptides and proteins (PPs) have been widely used in medicine, beginning with insulin therapy in patients with diabetes mellitus over a century ago. Although the oral route of drug administration is the preferred one by the vast majority of patients and improves compliance, medications of this kind due to their specific chemical structure are typically delivered parenterally, which ensures optimal bioavailability. In order to overcome issues connected with oral absorption of PPs such as their instability depending on digestive enzymes and pH changes in the gastrointestinal (GI) system on the one hand, but also their limited permeability across physiological barriers (mucus and epithelium) on the other hand, scientists have been strenuously searching for novel delivery methods enabling peptide and protein drugs (PPDs) to be administered enterally. These include utilization of different nanoparticles, transport channels, substances enhancing permeation, chemical modifications, hydrogels, microneedles, microemulsion, proteolytic enzyme inhibitors, and cell-penetrating peptides, all of which are extensively discussed in this review. Furthermore, this article highlights oral PP therapeutics both previously used in therapy and currently available on the medical market.

Boosting Fitness Costs Associated with Antibiotic Resistance in the Gut: On the Way to Biorestoration of Susceptible Populations

The acquisition and expression of antibiotic resistance implies changes in bacterial cell physiology, imposing fitness costs. Many human opportunistic pathogenic bacteria, such as those causing urinary tract or bloodstream infections, colonize the gut. In this opinionated review, we will examine the various types of stress that these bacteria might suffer during their intestinal stay. These stresses, and their compensatory responses, probably have a fitness cost, which might be additive to the cost of expressing antibiotic resistance. Such an effect could result in a disadvantage relative to antibiotic susceptible populations that might replace the resistant ones. The opinion proposed in this paper is that the effect of these combinations of fitness costs should be tested in antibiotic resistant bacteria with susceptible ones as controls. This testing might provide opportunities to increase the bacterial gut stress boosting physiological biomolecules or using dietary interventions. This approach to reduce the burden of antibiotic-resistant populations certainly must be answered empirically. In the end, the battle against antibiotic resistance should be won by antibiotic-susceptible organisms. Let us help them prevail.

Gastrointestinal microbiota and metabolites possibly contribute to distinct pathogenicity of SARS-CoV-2 proto or its variants in rhesus monkeys

Gastrointestinal (GI) infection is evidenced with involvement in COVID-19 pathogenesis caused by SARS-CoV-2. However, the correlation between GI microbiota and the distinct pathogenicity of SARS-CoV-2 Proto and its emerging variants remains unclear. In this study, we aimed to determine if GI microbiota impacted COVID-19 pathogenesis and if the effect varied between SARS-CoV-2 Proto and its variants. We performed an integrative analysis of histopathology, microbiomics, and transcriptomics on the GI tract fragments from rhesus monkeys infected with SARS-CoV-2 proto or its variants. Based on the degree of pathological damage and microbiota profile in the GI tract, five of SARS-CoV-2 strains were classified into two distinct clusters, namely, the clusters of Alpha, Beta and Delta (ABD), and Proto and Omicron (PO). Notably, the abundance of potentially pathogenic microorganisms increased in ABD but not in the PO-infected rhesus monkeys. Specifically, the high abundance of UCG-002, UCG-005, and Treponema in ABD virus-infected animals positively correlated with interleukin, integrins, and antiviral genes. Overall, this study revealed that infection-induced alteration of GI microbiota and metabolites could increase the systemic burdens of inflammation or pathological injury in infected animals, especially in those infected with ABD viruses. Distinct GI microbiota and metabolite profiles may be responsible for the differential pathological phenotypes of PO and ABD virus-infected animals. These findings improve our understanding the roles of the GI microbiota in SARS-CoV-2 infection and provide important information for the precise prevention, control, and treatment of COVID-19.

Portulaca oleracea L. polysaccharide alleviates dextran sulfate sodium-induced ulcerative colitis by regulating intestinal homeostasis

Portulaca oleracea L. (purslane) is a vegetable that contains a variety of active compounds with nutritional properties and has the potential to treat ulcerative colitis (UC). However, the mechanisms underlying the effects of Portulaca oleracea L. polysaccharide (POP) in alleviating UC remain unclear. In this study, we prepared an aqueous extract of purslane and separated a fraction with molecular weight >10 kDa using membrane separation. This fraction was used to isolate POP. The effect of POP on gut microbiota and colon transcriptome in dextran sulfate sodium-induced UC model mice was evaluated. POP treatment reduced inflammation and oxidative stress imbalance in UC mice. In addition, POP improved the intestinal barrier and regulated intestinal homeostasis. Importantly, POP was found to regulate gut microbiota, maintain the levels of retinol and short-chain fatty acids in the gut, promote the proliferation and differentiation of B cells in the colon, and increase the expression of immunoglobulin A. These results provide novel insights into the role of POP in regulating intestinal homeostasis, which should guide further development of POP as a functional food.

Gut microbiota in parasite-transmitting gastropods

BACKGROUND

Gastropoda, the largest class within the phylum Mollusca, houses diverse gut microbiota, and some gastropods serve as intermediate hosts for parasites. Studies have revealed that gut bacteria in gastropods are associated with various biological aspects, such as growth, immunity and host-parasite interactions. Here, we summarize our current knowledge of gastropod gut microbiomes and highlight future research priorities and perspectives.

METHODS

A literature search was undertaken using PubMed, Web of Science and CNKI for the articles on the gut microbiota of gastropods until December 31, 2022. We retrieved a total of 166 articles and identified 73 eligible articles for inclusion in this review based on the inclusion and exclusion criteria.

RESULTS

Our analysis encompassed freshwater, seawater and land snails, with a specific focus on parasite-transmitting gastropods. We found that most studies on gastropod gut microbiota have primarily utilized 16S rRNA gene sequencing to analyze microbial composition, rather than employing metagenomic, metatranscriptomic, or metabolomic approaches. This comprehensive review provided an overview of the parasites carried by snail species in the context of gut microbiota studies. We presented the gut microbial trends, a comprehensive summary of the diversity and composition, influencing factors, and potential functions of gastropod gut microbiota. Additionally, we discussed the potential applications, research gaps and future perspectives of gut microbiomes in parasite-transmitting gastropods. Furthermore, several strategies for enhancing our comprehension of gut microbiomes in snails were also discussed.

CONCLUSIONS

This review comprehensively summarizes the current knowledge on the composition, potential function, influencing factors, potential applications, limitations, and challenges of gut microbiomes in gastropods, with a specific emphasis on parasite-transmitting gastropods. These findings provide important insights for future studies aiming to understand the potential role of gastropod gut microbiota in controlling snail populations and snail-borne diseases.

Oral vancomycin treatment suppresses gut trypsin activity and preserves intestinal barrier function during EAE

Studies have reported increased intestinal permeability in multiple sclerosis (MS) patients and its mouse model experimental autoimmune encephalomyelitis (EAE). However, the mechanisms driving increased intestinal permeability that in turn exacerbate neuroinflammation during EAE remain unclear. Here we showed that vancomycin preserved the integrity of the intestinal barrier, while also suppressing gut trypsin activity, enhancing the relative abundance of specific Lactobacilli and ameliorating disease during EAE. Furthermore, Lactobacilli enriched in the gut of vancomycin-treated EAE mice at day 3 post immunization negatively correlated with gut trypsin activity and EAE severity. In untreated EAE mice, we observed increased intestinal permeability and increased intestinal protease activated receptor 2 (PAR2) expression at day 3 post immunization. Prior studies have shown that trypsin increases intestinal permeability by activating PAR2. Our results suggest that the interaction between intestinal PAR2 and trypsin may be a key modulator of intestinal permeability and disease severity during EAE.

Effect of purple sweet potato-derived anthocyanins on heat stress response in Wenchang chickens and preliminary mechanism study

This study was conducted to investigate the beneficial effect of purple sweet potato anthocyanins (PSPA) on growth performance, oxidative status, immune response, intestinal morphology, and intestinal flora homeostasis in heat-stressed Wenchang chickens. A total of 100 Wenchang chickens (50-day-old) were randomly assigned to 5 groups, including the thermoneutral environment (TN) group (26°C); high-temperature stressed (HS) group (33°C ± 1°C); low-dose PSPA treatment (L_HS) group (8 mg/kg body weight, 33°C ± 1°C); medium-dose PSPA treatment (M_HS) group and high-dose PSPA treatment (H_HS) group (16 mg/kg and 32 mg/kg body weight, respectively, 33°C ± 1°C). The results showed that PSPA reversed the adverse effects of heat stress on growth performance, meat quality, and carcass characteristics. And the effect was associated with the concentration of PSPA partially. Heat stress increased the serum lipids of Wenchang chickens. LDL-C, TG, TC, and FFA in the serum were significantly decreased, and HDL-C and LPS in the serum were increased by PSPA treatment. The digestive enzymes in duodenal chyme were significantly (P < 0.05) increased by PSPA treatment. And PSPA treatment significantly (P < 0.05) enhanced the redox status by improving antioxidant parameters (GSH-Px and SOD) and decreasing the MDA level in the serum and liver. Moreover, the level of inflammatory cytokines was significantly (P < 0.05) regulated by PSPA treatment compared to the HS group. The villus length and goblet cell numbers after PSPA treatment were significantly higher than HS group. Furthermore, PSPA also played protection on the intestine structure by decreasing the level of D-LA and DAO. 16S rRNA sequencing revealed the microbial composition was altered by PSPA, and Acetanaerobacterium and Oscillibacter were dominant in the H_HS group. Microbial functional prediction indicated that function pathways based on KEGG and metacyc database were regulated by PSPA, and intestinal flora correlated with metabolic function significantly. The spearman correlation analysis showed that Saccharibacteria and Clostridium_IV correlated with the serum lipids, antioxidant, and inflammatory cytokines. Collectively, these findings suggest that PSPA has a positive effect against heat stress in poultry.

Self-assembled super-small AIEgen nanoprobe for highly sensitive and selective detection of protamine and trypsin

Amphiphilic aggregation-induced emission (AIE) molecules show superior potential for fabricating novel ultrasmall nanoprobes. Here, an anionic dipyridyl tetraphenylethene (TPE) derivative is rationally designed and a super-small self-assembled AIEgen nanoprobe (TPE-2Py-SO₃NaNPs, ca. 2.48 nm) is thus conveniently constructed for the supersensitive detection of protamine and trypsin. In HEPES/DMSO solution (8 : 2, v/v, pH = 7.4), negatively charged TPE-2Py-SO₃NaNPs exhibited an AIE effect in the presence of positively charged protamine, presenting a fluorescence enhancement at 498 nm together with a large Stokes shift of 150 nm and a low detection limit of 8.0 ng mL^-1. In addition, the in situ formed TPE-2Py-SO₃Na/protamine nanocomposite can be dissociated by trypsin due to the highly selective degradation of protamine via enzymatic hydrolysis, achieving a detection limit for trypsin as low as 5.0 ng mL^-1.

Protective Effects of Different Molecular Weights of Purslane (Portulaca oleracea L.) Aqueous Extract on DSS-Induced Ulcerative Colitis in Mice

Purslane, a common wild vegetable, contains active substances with various biological functions. However, its effects have been under-investigated in ulcerative colitis (UC). Therefore, this study investigated the therapeutic effects of purslane macromolecular (POEM) and small molecular extracts (POES) on dextran sulfate sodium (DSS)-induced UC in mice. Membrane separation was used to obtain extracts of different molecular weights, and their compositional differences were compared using liquid chromatography-mass spectrometry (LC/MS). POEM contained more proteins and polysaccharides, whereas POES contained more organic acids and alkaloids. These differences in composition were directly responsible for the different degrees of remission of the alleviated UC in model mice. POEM may alleviate UC by regulating the antioxidant capacity and the gut microbiota, whereas the major alleviatory effect of POES was primarily related to the regulation of antioxidant capacity. The POEM and POES effects identified in this study provide a theoretical basis for the development of purslane as a functional food.

Designing self-triggered micro/milli devices for gastrointestinal tract drug delivery

INTRODUCTION

Self-triggered micro-/milli-devices (STMDs), which are artificial devices capable of responding to the surrounding environment and transferring external energy into kinetic energy, thus realizing autonomous movement, have come to the forefront as a powerful tool in cargo delivery via gastrointestinal tract. Urgent needs have been raised to overview the development of this area.

AREAS COVERED

We summarize the advancement of designing STMDs for delivery via gastrointestinal tract. We first give a brief overview on the opportunities and challenges of delivery via gastrointestinal tract involving gastric barriers and intestinal barriers. Then, emphasis is laid on the design and applications of STMDs for delivery via gastrointestinal tract. We focus on their morphological characteristics and function design, expounding their working mechanisms in the complex gastrointestinal tract.

EXPERT OPINION

Although with much progress in STMDs, there is still a huge gap between laboratory researches and clinical applications due to some limitations including latent digestive burden, sophisticated fabrication, unstable delivery, and so on. We give a discussion on the potential, challenges, and prospects of developing STMDs for delivery via gastrointestinal tract.

Characteristics of Intestinal Microbiota in Japanese Patients with Mild Cognitive Impairment and a Risk-Estimating Method for the Disorder

Intestinal microbiota may play a significant role in the development and progression of mild cognitive impairment (MCI). In addition, sex differences in the prevalence of MCI and intestinal microbiota are likely to exist. Therefore, this study investigated the association between MCI and intestinal microbiota by comparing Japanese patients in their 70s with MCI (11 males and 18 females) and disease-free controls (17 males and 23 females), taking sex into account. In both sexes, Clostridium_XVIII, Eggerthella, Erysipelatoclostridium, Flavonifractor, and Ruminococcus 2 were the more abundant taxa in the MCI group, whereas Megasphaera, Oscillibacter, Prevotella, Roseburia, and Victivallis were less abundant. Based on these characteristics, it was hypothesized that the composition of the intestinal microbiota in the MCI group leads to dysregulation of the intestinal microbiota, increased intestinal and blood-brain barrier permeability, and increased chronic neuroinflammation, with the long-term persistence of these abnormalities ultimately leading to cognitive decline. Furthermore, risk estimation models for MCI based on intestinal microbiota data were developed using structural equation modeling. These tests discriminated between the MCI and control groups. Incorporating these factors into intestinal microbiota testing using stool samples may be an efficient method to screen individuals with MCI.

Effect of Panax ginseng and Fructus Mume on Intestinal Barrier and Gut Microbiota in Rats with Diarrhea

Panax ginseng and Fructus mume (Renshen Wumei in Chinese, RW) are natural medicines with high nutritional and pharmacological value. They have been widely used together in China to treat gastrointestinal diseases, especially persistent diarrhea, but the potential mechanisms remain elusive. In this study, a diarrhea model was established in rats using a 30% aqueous extract of senna. The therapeutic effects of RW were evaluated by recording the prevalence of loose stools, the diarrhea index, and histopathological changes in colon tissue. The levels of mucins, tight junction (TJ) proteins, inflammatory cytokines, and phosphoinositide 3-kinase/Akt/nuclear factor-κB (PI3K/Akt/NF-κB) signaling pathway proteins were measured. Metagenomic sequencing was used to analyze the gut microbiota. Treatment with RW alleviated injury to the intestinal barrier in rats with diarrhea and also upregulated levels of Muc2 and TJ proteins, such as occludin, zonula occludens-1, and claudin-1. Administration of RW regulated the structure of the gut microbiota in diarrheal rats. Furthermore, RW suppressed levels of interleukin (IL), tumor necrosis factor (TNF)-α, IL-1, PI3K, Akt, and p-NF-κB p65 and also increased IL-4 levels. Our study indicates that P. ginseng and Fructus mume help improve the symptoms of diarrhea, possibly by alleviating the intestinal barrier injury, regulating intestinal flora composition, and inhibiting the PI3K/Akt/NF-κB signaling pathway.

The Genetic Background Is Shaping Cecal Enlargement in the Absence of Intestinal Microbiota

Germ-free (GF) rodents have become a valuable tool for studying the role of intestinal microbes on the host physiology. The major characteristic of GF rodents is an enlarged cecum. The accumulation of mucopolysaccharides, digestion enzymes and water in the intestinal lumen drives this phenotype. Microbial colonization normalizes the cecum size in ex-GF animals. However, whether strain genetics influences the cecal enlargement is unknown. Here we investigated the impact of mouse genetic background on the cecal size in five GF strains frequently used in biomedical research. The cecal weight of GF mice on B6 background (B6J and B6N) represented up to 20% of total body weight. GF NMRI and BALBc mice showed an intermediate phenotype of 5-10%, and those on the C3H background of up to 5%. Reduced cecal size in GF C3H mice correlated with decreased water content, increased expression of water transporters, and reduced production of acidic mucins, but was independent of the level of digestive enzymes in the lumen. In contrast, GF B6J mice with greatly enlarged cecum showed increased water content and a distinct metabolic profile characterized by altered amino acid and bile acid metabolism, and increased acidic mucin production. Together, our results show that genetic background influences the cecal enlargement by regulating the water transport, production of acidic mucins, and metabolic profiles.

The emerging roles of bacterial proteases in intestinal diseases

Proteases are an evolutionarily conserved family of enzymes that degrade peptide bonds and have been implicated in several common gastrointestinal (GI) diseases. Although luminal proteolytic activity is important for maintenance of homeostasis and health, the current review describes recent advances in our understanding of how overactivity of luminal proteases contributes to the pathophysiology of celiac disease, irritable bowel syndrome, inflammatory bowel disease and GI infections. Luminal proteases, many of which are produced by the microbiota, can modulate the immunogenicity of dietary antigens, reduce mucosal barrier function and activate pro-inflammatory and pro-nociceptive host signaling. Increased proteolytic activity has been ascribed to both increases in protease production and decreases in inhibitors of luminal proteases. With the identification of strains of bacteria that are important sources of proteases and their inhibitors, the stage is set to develop drug or microbial therapies to restore protease balance and alleviate disease.