In Vivo Visualization and Quantification of Mitochondrial Morphology in C. elegans.

Caenorhabditis elegans is a highly versatile model system, intensively used for functional, genetic, cytometric, and integrative studies. Due to its simplicity and large muscle cell number, C. elegans has frequently been used to study mitochondrial deficiencies caused by disease or drug toxicity. Here we describe a robust and efficient method to visualize and quantify mitochondrial morphology in vivo. This method has many practical and technical advantages above traditional (manual) methods and provides a comprehensive analysis of mitochondrial morphology.

Correlations between microbiota and metabolites after faecal microbiota transfer in irritable bowel syndrome.

Faecal microbiota transfer (FMT) consists of the infusion of donor faecal material into the intestine of a patient with the aim to restore a disturbed gut microbiota. In this study, it was investigated whether FMT has an effect on faecal microbial composition, its functional capacity, faecal metabolite profiles and their interactions in 16 irritable bowel syndrome (IBS) patients. Faecal samples from eight different time points before and until six months after allogenic FMT (faecal material from a healthy donor) as well as autologous FMT (own faecal material) were analysed by 16S RNA gene amplicon sequencing and gas chromatography coupled to mass spectrometry (GS-MS). The results showed that the allogenic FMT resulted in alterations in the microbial composition that were detectable up to six months, whereas after autologous FMT this was not the case. Similar results were found for the functional profiles, which were predicted from the phylogenetic sequencing data. While both allogenic FMT as well as autologous FMT did not have an effect on the faecal metabolites measured in this study, correlations between the microbial composition and the metabolites showed that the microbe-metabolite interactions seemed to be disrupted after allogenic FMT compared to autologous FMT. This shows that FMT can lead to altered interactions between the gut microbiota and its metabolites in IBS patients. Further research should investigate if and how this affects efficacy of FMT treatments.

Gut dysbacteriosis and intestinal disease: mechanism and treatment.

The gut microbiome functions like an endocrine organ, generating bioactive metabolites, enzymes or small molecules that can impact host physiology. Gut dysbacteriosis is associated with many intestinal diseases including (but not limited to) inflammatory bowel disease, primary sclerosing cholangitis-IBD, irritable bowel syndrome, chronic constipation, osmotic diarrhoea and colorectal cancer. The potential pathogenic mechanism of gut dysbacteriosis associated with intestinal diseases includes the alteration of composition of gut microbiota as well as the gut microbiota-derived signalling molecules. The many correlations between the latter and the susceptibility for intestinal diseases has placed a spotlight on the gut microbiome as a potential novel target for therapeutics. Currently, faecal microbial transplantation, dietary interventions, use of probiotics, prebiotics and drugs are the major therapeutic tools utilized to impact dysbacteriosis and associated intestinal diseases. In this review, we systematically summarized the role of intestinal microbiome in the occurrence and development of intestinal diseases. The potential mechanism of the complex interplay between gut dysbacteriosis and intestinal diseases, and the treatment methods are also highlighted.

Effect of fructans, prebiotics and fibres on the human gut microbiome assessed by 16S rRNA-based approaches: a review.

The inherent and diverse capacity of dietary fibres, nondigestible oligosaccharides (NDOs) and prebiotics to modify the gut microbiota and markedly influence health status of the host has attracted rising interest. Research and collective initiatives to determine the composition and diversity of the human gut microbiota have increased over the past decade due to great advances in high-throughput technologies, particularly the 16S ribosomal RNA (rRNA) sequencing. Here we reviewed the application of 16S rRNA-based molecular technologies, both community wide (sequencing and phylogenetic microarrays) and targeted methodologies (quantitative PCR, fluorescent in situ hybridisation) to study the effect of chicory inulin-type fructans, NDOs and specific added fibres, such as resistant starches, on the human intestinal microbiota. Overall, such technologies facilitated the monitoring of microbiota shifts due to prebiotic/fibre consumption, though there are limited community-wide sequencing studies so far. Molecular studies confirmed the selective bifidogenic effect of fructans and galactooligosaccharides (GOS) in human intervention studies. Fructans only occasionally decreased relative abundance of Bacteroidetes or stimulated other groups. The sequencing studies for various resistant starches, polydextrose and beta-glucan showed broader effects with more and different types of gut microbial species being enhanced, often including phylotypes of Ruminococcaceae. There was substantial variation in terms of magnitude of response and in individual responses to a specific fibre or NDO which may be due to numerous factors, such as initial presence and relative abundance of a microbial type, diet, genetics of the host, and intervention parameters, such as intervention duration and fibre dose. The field will clearly benefit from a more systematic approach that will support defining the impact of prebiotics and fibres on the gut microbiome, identify biomarkers that link gut microbes to health, and address the personalised response of an individual's microbiota to prebiotics and dietary fibres.

Metabolic improvement in obese patients after duodenal-jejunal exclusion is associated with intestinal microbiota composition changes.

BACKGROUND: Intestinal microbiota have been suggested to play an important role in the pathogenesis of obesity and type 2 diabetes. Bariatric surgery improves both conditions and has been associated with changes in intestinal microbiota composition. We investigated the effect of a nonsurgical bariatric technique on intestinal microbiota composition in relation to metabolic improvement. METHODS: Seventeen patients with obesity and type 2 diabetes were treated with the nonsurgical duodenal-jejunal bypass liner, which excludes the proximal 60 cm small intestine from food. Fecal samples as well as metabolic parameters reflecting obesity and type 2 diabetes were obtained from the patients at baseline, after 6 months with the device in situ, and 6 months after explantation. RESULTS: After 6 months of treatment, both obesity and type 2 diabetes had improved with a decrease in weight from 106.1 [99.4-123.5] to 97.4 [89.4-114.0] kg and a decrease in HbA1c from 8.5% [7.6-9.2] to 7.2% [6.3-8.1] (both p < 0.05). This was paralleled by an increased abundance of typical small intestinal bacteria such as Proteobacteria, Veillonella, and Lactobacillus spp. in feces. After removal of the duodenal-jejunal bypass liner, fecal microbiota composition was similar to that observed at baseline, despite persistent weight loss. CONCLUSION: Improvement of obesity and type 2 diabetes after exclusion of the proximal 60 cm small intestine by treatment with a nonsurgical duodenal-jejunal bypass liner may be promoted by changes in fecal microbiota composition.

Strontium fails to induce Ca2+ release and activation in human oocytes despite the presence of functional TRPV3 channels.

STUDY QUESTION: Are the transient receptor potential cation channels vanilloid 3 (TRPV3) present and able to mediate strontium (Sr2+) induced artificial activation in human oocytes? SUMMARY ANSWER: Sr2+ did not induce Ca2+ rises or provoke activation in human oocytes, however, mRNA for the TRPV3 channel was present in metaphase II (MII) human oocytes after IVM and TRPV3 agonists induced Ca2+ rises and oocyte activation, demonstrating the channels were functional. WHAT IS KNOWN ALREADY: Selective activation of TRPV3 by agonists induces Ca2+ entry and promotes mouse oocyte activation, and the absence of TRPV3 channels in mouse oocytes prevents Sr2+ mediated artificial activation. Sr2+ is sometimes used to overcome fertilization failure after ICSI in the clinic, but its efficiency is still controversial and the mechanism(s) of how it mediates the Ca2+ flux has not been studied yet in human. STUDY DESIGN SIZE DURATION: The protein distribution (n = 10) and mRNA expression level (n = 19) of the TRPV3 channels was investigated in human MII oocytes after IVM. The Sr2+ (10 mM) and TRPV3 agonists (200 µM 2-aminoethoxydiphenyl borate [2-APB] and 200 µM carvacrol)-induced Ca2+ response was analyzed in human (n = 15, n = 16 and n = 16, respectively) and mouse oocytes (n = 15, n = 19 and n = 26, respectively). The subsequent embryonic developmental potential following the parthenogenetic activation using these three agents was recorded in human (n = 10, n = 9 and n = 9, respectively) and mouse (n = 20 per agent) oocytes, by determining pronucleus, or 2-cell and blastocyst formation rates. PARTICIPANTS/MATERIALS SETTING METHODS: MII oocytes from B6D2F1 mice (6-10 weeks old) as well as human IVM oocytes and IVO oocytes (from patients aged 25-38 years old) with aggregates of smooth endoplasmic reticulum clusters were used. The expression of TRPV3 channels was determined by immunofluorescence staining with confocal microscopy and RT-PCR, and the temporal evolution of intracellular Ca2+ concentration was measured by time-lapse imaging after exposure to Sr2+ and TRPV3 agonists (2-APB and carvacrol). Artificial activation efficiency was assessed using these agents. MAIN RESULTS AND THE ROLE OF CHANCE: Sr2+ did not promote Ca2+ oscillations or provoke activation in human oocytes. Transcripts of TRPV3 channels were present in IVM MII human oocytes. TRPV3 protein was expressed and distributed throughout the ooplasm of human oocytes, rather than particularly concentrated in plasma membrane as observed in mouse MII oocytes. Both agonists of TRPV3 (2-APB and carvacrol), promoted a single Ca2+ transient and activated a comparable percentage of more than half of the exposed human oocytes (P > 0.05). The agonist 2-APB was also efficient in activating mouse oocytes, however, significantly fewer mouse oocytes responded to carvacrol than 2-APB in both the Ca2+ analysis and activation test (P < 0.001). LIMITATIONS REASONS FOR CAUTION: The availability of fresh IVO matured oocytes in human was limited. Data from TRPV3 knockout model are not included. WIDER IMPLICATIONS OF THE FINDINGS: The benefit of clinical application using Sr2+ to overcome fertilization failure after ICSI requires further validation. STUDY FUNDING/COMPETING INTERESTS: This study was supported by FWO-Vlaanderen, China Scholarship Council and Special Research Fund from Ghent University (Bijzonder Onderzoeksfonds, BOF). No competing interests are declared.

C4B gene influences intestinal microbiota through complement activation in patients with paediatric-onset inflammatory bowel disease.

Complement C4 genes are linked to paediatric inflammatory bowel disease (PIBD), but the mechanisms have remained unclear. We examined the influence of C4B gene number on intestinal microbiota and in-vitro serum complement activation by intestinal microbes in PIBD patients. Complement C4A and C4B gene numbers were determined by genomic reverse transcription-polymerase chain reaction (RT-PCR) from 64 patients with PIBD (Crohn's disease or ulcerative colitis). The severity of the disease course was determined from faecal calprotectin levels. Intestinal microbiota was assessed using the HITChip microarray. Complement reactivity in patients was analysed by incubating their sera with Yersinia pseudotuberculosis and Akkermansia muciniphila and determining the levels of C3a and soluble terminal complement complex (SC5b-9) using enzyme immunoassays. The microbiota diversity was wider in patients with no C4B genes than in those with one or two C4B genes, irrespective of intestinal inflammation. C4B and total C4 gene numbers correlated positively with soluble terminal complement complex (TCC, SC5b-9) levels when patient serum samples were stimulated with bacteria. Our results suggest that the C4B gene number associates positively with inflammation in patients with PIBD. Multiple copies of the C4B gene may thus aggravate the IBD-associated dysbiosis through escalated complement reactivity towards the microbiota.

Childhood BMI in relation to microbiota in infancy and lifetime antibiotic use.

BACKGROUND: Children with high body mass index (BMI) at preschool age are at risk of developing obesity. Early identification of factors that increase the risk of excessive weight gain could help direct preventive actions. The intestinal microbiota and antibiotic use have been identified as potential modulators of early metabolic programming and weight development. To test if the early microbiota composition is associated with later BMI, and if antibiotic use modifies this association, we analysed the faecal microbiota composition at 3 months and the BMI at 5-6 years in two cohorts of healthy children born vaginally at term in the Netherlands (N = 87) and Finland (N = 75). We obtained lifetime antibiotic use records and measured weight and height of all children. RESULTS: The relative abundance of streptococci was positively and the relative abundance of bifidobacteria negatively associated with the BMI outcome. The association was especially strong among children with a history of antibiotic use. Bacteroides relative abundance was associated with BMI only in the children with minimal lifetime antibiotic exposure. CONCLUSIONS: The intestinal microbiota of infants are predictive of later BMI and may serve as an early indicator of obesity risk. Bifidobacteria and streptococci, which are indicators of microbiota maturation in infants, are likely candidates for metabolic programming of infants, and their influence on BMI appears to depend on later antibiotic use.

Produced water treatment by membranes: A review from a colloidal perspective.

While the world faces an increased scarcity in fresh water supply, it is of great importance that water from industry and waste streams can be treated for re-use. One of the largest waste streams in the oil and gas industry is produced water. After the phase separation of oil and gas, the produced water is left. This mixture contains dissolved and dispersed hydrocarbons, surfactants, clay particles and salts. Before this water can be used for re-injection, irrigation or as industrial water, it has to be treated. Conventional filtration techniques such as multi media filters and cartridge filters, are able to remove the majority of the contaminants, but the smallest, stabilized oil droplets (<10µm) remain present in the treated water. In recent years, research has focused on membranes to remove these small oil droplets, because this technology requires no frequent replacement of filters and the water quality after treatment is better. Membranes however suffer from fouling by the contaminants in produced water, leading to a lower clean water flux and increased energy costs. Current research on produced water treatment by membranes is mainly focused on improving existing processes and developing fouling-resistant membranes. Multiple investigations have determined the importance of different factors (such as emulsion properties and operating conditions) on the fouling process, but understanding the background of fouling is largely absent. In this review, we describe the interaction between the membrane and a produced water emulsion from a colloidal perspective, with the aim to create a clear framework that can lead to much more detailed understanding of membrane fouling in produced water treatment. Better understanding of the complex interactions at the produced water/membrane interface is essential to achieve more efficient applications.

Preparation and preservation of viable Akkermansia muciniphila cells for therapeutic interventions.

The anaerobic gut bacterium Akkermansia muciniphila is a well-characterised member of the mucosal microbiota and has shown to be a gut symbiont in human. A. muciniphila has been negatively associated with obesity and its associated metabolic disorders in various human cohorts while treatment with A. muciniphila cells reversed highfat diet-induced obesity and its associated metabolic disorders in mouse models. Therefore, administration of A. muciniphila has been suggested as a possible new therapeutic treatment for these omnipresent diseases. Here we describe a potentially scalable workflow for the preparation and preservation of high numbers of viable cells of A. muciniphila obtained from 1 l laboratory scale growth under strict anaerobic conditions for therapeutic interventions. This resulted in viable A. muciniphila cells with high yields and very high stability, with up to 97.9±4.5% survival for a time period of 1 year at -80 °C in glycerol-amended medium. Moreover, various quality assessment and control procedures were developed to ensure the use of viable cells of A. muciniphila. Several microscopic, culturing, and molecular approaches were applied to monitor the presence, abundance and recovery of A. muciniphila before, during, and after its administration to high-fat treated mice. We show that viable A. muciniphila cells can be recovered from caecal and colon content (up to 1×1010 cells/g), testifying for the efficiency of the described workflow.

Consensus report: faecal microbiota transfer - clinical applications and procedures.

BACKGROUND: Faecal microbiota transplantation or transfer (FMT) aims at replacing or reinforcing the gut microbiota of a patient with the microbiota from a healthy donor. Not many controlled or randomised studies have been published evaluating the use of FMT for other diseases than Clostridium difficile infection, making it difficult for clinicians to decide on a suitable indication. AIM: To provide an expert consensus on current clinical indications, applications and methodological aspects of FMT. METHODS: Well-acknowledged experts from various countries in Europe have contributed to this article. After literature review, consensus has been achieved by repetitive circulation of the statements and the full manuscript among all authors with intermittent adaptation to comments (using a modified Delphi process). Levels of evidence and agreement were rated according to the GRADE system. Consensus was defined a priori as agreement by at least 75% of the authors. RESULTS: Key recommendations include the use of FMT in recurrent C. difficile infection characterised by at least two previous standard treatments without persistent cure, as well as its consideration in severe and severe-complicated C. difficile infection as an alternative to total colectomy in case of early failure of antimicrobial therapy. FMT in inflammatory bowel diseases (IBD), irritable bowel syndrome (IBS) and metabolic syndrome should only be performed in research settings. CONCLUSIONS: Faecal microbiota transplantation or transfer is a promising treatment for a variety of diseases in which the intestinal microbiota is disturbed. For indications other than C. difficile infection, more evidence is needed before more concrete recommendations can be made.

In vitro colonisation of the distal colon by Akkermansia muciniphila is largely mucin and pH dependent.

Host mucin is the main constituent of the mucus layer that covers the gut epithelium of the host, and an important source of glycans for the bacteria colonising the intestine. Akkermansia muciniphila is a mucin-degrading bacterium, abundant in the human gut, that is able to produce acetate and propionate during this degradation process. A. muciniphila has been correlated with human health in previous studies, but a mechanistic explanation is lacking. In this study, the main site of colonisation was characterised alongside additional conditions, such as differences in colon pH, prebiotic supplementation and variable mucin supply. To overcome the limitations of in vivo studies concerning variations in mucin availability and difficult access to proximal regions of the colon, a dynamic in vitro gut model (SHIME) was used. In this model, A. muciniphila was found to colonise the distal colon compartment more abundantly than the proximal colon ((±8 log copies/ml compared to ±4 log copies/ml) and the preference for the distal compartment was found to be pH-dependent. The addition of mucin caused a specific increase of A. muciniphila (±4.5 log increase over two days), far exceeding the response of other bacteria present, together with an increase in propionate. These findings suggest that colonisation and mucin degradation by A. muciniphila is dependent on pH and the concentration of mucin. Our results revealed the preference of A. muciniphila for the distal colon environment due to its higher pH and uncovered the quick and stable response of A. muciniphila to mucin supplementation.

In silico synchronization reveals regulators of nuclear ruptures in lamin A/C deficient model cells.

The nuclear lamina is a critical regulator of nuclear structure and function. Nuclei from laminopathy patient cells experience repetitive disruptions of the nuclear envelope, causing transient intermingling of nuclear and cytoplasmic components. The exact causes and consequences of these events are not fully understood, but their stochastic occurrence complicates in-depth analyses. To resolve this, we have established a method that enables quantitative investigation of spontaneous nuclear ruptures, based on co-expression of a firmly bound nuclear reference marker and a fluorescent protein that shuttles between the nucleus and cytoplasm during ruptures. Minimally invasive imaging of both reporters, combined with automated tracking and in silico synchronization of individual rupture events, allowed extracting information on rupture frequency and recovery kinetics. Using this approach, we found that rupture frequency correlates inversely with lamin A/C levels, and can be reduced in genome-edited LMNA knockout cells by blocking actomyosin contractility or inhibiting the acetyl-transferase protein NAT10. Nuclear signal recovery followed a kinetic that is co-determined by the severity of the rupture event, and could be prolonged by knockdown of the ESCRT-III complex component CHMP4B. In conclusion, our approach reveals regulators of nuclear rupture induction and repair, which may have critical roles in disease development.

Akkermansia muciniphila: a novel functional microbe with probiotic properties.

Akkermansia muciniphila is an intestinal anaerobe which has been proposed as a new functional microbe with probiotic properties. However, the species is not included in the European Union qualified presumption of safety (QPS) list and has not yet been assessed. Moreover, products containing A. muciniphila are not on the market and are thus controlled by the Novel Foods Regulation, which requires extensive safety assessment. This review addresses the safety aspects of the use of A. muciniphila based on published information on its functions in humans and predictions based on its activity in model animals. Further, comprehensive studies related to A. muciniphila and its safety properties have gradually appeared and are summarised here. Many of the criteria required for novel food safety assessment in Europe can thus be fulfilled. However, studies focusing on the toxicological properties of A. muciniphila, including long-term and reproduction studies, have not so far been reported and are discussed in the light of the observation that most, if not all, healthy subjects are known to carry this intestinal anaerobe. As this also applies to other beneficial bacteria found in the human intestinal tract, the A. muciniphila case can be seen as a model for the comprehensive safety evaluations required by the European authorities.

Interaction of mouse splenocytes and macrophages with bacterial strains in vitro: the effect of age in the immune response.

Probiotics influence the immune system, both at the local and systemic level. Recent findings suggest the relation between microbiota and the immune system alters with age. Our objective was to address direct effects of six bacterial strains on immune cells from young and aged mice: Lactobacillus plantarum WCFS1, Lactobacillus casei BL23, Lactococcus lactis MG1363, Bifidobacterium breve ATCC15700, Bifidobacterium infantis ATCC15697, and Akkermansia muciniphila ATCC BAA-835. We used splenocytes and naïve or interferon-γ-stimulated bone marrow-derived macrophages (BMDM) as responder populations. All tested bacterial strains induced phenotypic and cytokine responses in splenocytes and BMDM. Based on magnitude of the cellular inflammatory response and cytokine profiles, two subgroups of bacteria were identified, i.e. L. plantarum and L. casei versus B. breve, B. infantis, and A. muciniphila. The latter group of bacteria induced high levels of cytokines produced under inflammatory conditions, including tumour necrosis factor (TNF), interleukin (IL)-6 and IL-10. Responses to L. lactis showed features of both subgroups. In addition, we compared responses by splenocytes and BMDM derived from young mice to those of aged mice, and found that splenocytes and BMDM derived from aged mice had an increased IL-10 production and dysregulated IL-6 and TNF production compared to young immune cells. Overall, our study shows differential inflammatory responses to distinct bacterial strains, and profound age-dependent effects. These findings, moreover, support the view that immune environment importantly influences bacterial immune effects.

The relationship between faecal-associated and mucosal-associated microbiota in irritable bowel syndrome patients and healthy subjects.

BACKGROUND: The faecal-associated microbiota is commonly seen as a surrogate of the mucosal-associated microbiota. However, previous studies indicate that they are different. Furthermore, analyses of the mucosal microbiota are commonly done after standard bowel cleansing, affecting the microbial composition. AIM: To compare the mucosal-associated microbiota, obtained from unprepared colon, with faecal-associated microbiota in healthy subjects and irritable bowel syndrome (IBS) patients. METHODS: Faecal and mucosal biopsies were obtained from 33 IBS patients and 16 healthy controls. Of IBS patients, 49% belonged to the diarrhoea-predominant subgroup and 80% suffered from IBS symptoms during at least 5 years. Biopsies were collected from unprepared sigmoid colon and faecal samples a day before colonoscopy. Microbiota analyses were performed with a phylogenetic microarray and redundancy discriminant analysis. RESULTS: The composition of the mucosal- and the faecal-associated microbiota in unprepared sigmoid colon differs significantly (P = 0.002). Clinical characteristics of IBS did not correlate with this difference. Bacteroidetes dominate the mucosal-associated microbiota. Firmicutes, Actinobacteria and Proteobacteria dominate the faecal-associated microbiota. Healthy subjects had a significantly higher (P < 0.005) abundance (1.9%) of the bacterial group uncultured Clostridiales I in the mucosal-associated microbiota than IBS patients (0.3%). Bacterial diversity was higher in faecal- compared with mucosal-associated microbiota in IBS patients (P < 0.005). No differences were found in healthy subjects. CONCLUSIONS: Differences in the mucosal-associated microbiota between healthy individuals and IBS patients are minimal (one bacterial group) compared to differences in the faecal microbiota of both groups (53 bacterial groups). Microbial aberrations characterising IBS are more pronounced in the faeces than in the mucosa.

The gut microbiota in internal medicine: implications for health and disease.

The human gut microbiota may be viewed as an organ, executing numerous functions in metabolism, development of the immune system and host defence against pathogens. It may therefore be involved in the development of a range of diseases such as gastrointestinal infections, inflammatory bowel disease, allergy and diabetes mellitus. Reversely, certain therapies that are often used, such as antibiotics and chemotherapy, may negatively affect the composition and function of the gut microbiota and thereby the wellbeing of patients. As the microbiota research field is currently moving from association studies to intervention studies and even clinical trials, implementation of this new knowledge into clinical practice is coming near. Several therapeutic interventions that target the gut microbiota are being evaluated, ranging from supplementation of food components to transplantation of faecal microbiota. In this review we provide an overview of current literature on the gut microbiota in both a healthy state and a range of diseases that are relevant for internal medicine. In anticipation of gut microbiota-targeted therapies, it is important to realise the key function of the gut microbiota in physiological processes and the collateral damage that may be caused when disrupting this ecosystem within us.

Severity of atopic disease inversely correlates with intestinal microbiota diversity and butyrate-producing bacteria.

The reports on atopic diseases and microbiota in early childhood remain contradictory, and both decreased and increased microbiota diversity have been associated with atopic eczema. In this study, the intestinal microbiota signatures associated with the severity of eczema in 6-month-old infants were characterized. Further, the changes in intestinal microbiota composition related to the improvement of this disease 3 months later were assessed. The severity of eczema correlated inversely with microbiota diversity (r = -0.54, P = 0.002) and with the abundance of butyrate-producing bacteria (r = -0.52, P = 0.005). During the 3-month follow-up, microbiota diversity increased (P < 0.001) and scoring atopic dermatitis values decreased (P < 0.001) in all infants. This decrease coincided with the increase in bacteria related to butyrate-producing Coprococcus eutactus (r = -0.59, P = 0.02). In conclusion, the high diversity of microbiota and high abundance of butyrate-producing bacteria were associated with milder eczema, thus suggesting they have a role in alleviating symptoms of atopic eczema.

Altered faecal and mucosal microbial composition in post-infectious irritable bowel syndrome patients correlates with mucosal lymphocyte phenotypes and psychological distress.

BACKGROUND: A subset of irritable bowel syndrome (IBS) patients, denoted post-infectious IBS (PI-IBS), develop symptoms after an enteric infection. Bacterial dysbiosis and mucosal inflammation have been proposed to be involved in the pathophysiology of this entity. AIM: To characterise the mucosal and faecal microbiota in PI-IBS, general IBS and healthy controls, and to investigate associations between the microbiota and the mucosal immune system. METHODS: Mucosal biopsies and faeces were collected from 13 PI-IBS patients, 19 general IBS patients and 16 healthy controls. Global bacterial composition was determined by generating 16S rRNA amplicons that were examined by phylogenetic microarray hybridisation, principal component and redundancy analysis. We correlated previously reported lymphocyte proportions with the microbiota. RESULTS: Faecal microbiota composition of PI-IBS patients differed significantly from both general IBS patients and healthy controls (P < 0.02). Both mucosal (P < 0.01) and faecal (P = 0.05) microbial diversity were reduced in PI-IBS compared to healthy controls. In the intraepithelial lymphocytes the previously published proportion of CD8(+) CD45RA(+) was negatively correlated with mucosal microbial diversity (P < 0.005). The previously published number of lamina propria lymphocytes was negatively correlated with mucosal microbial diversity (P < 0.05). Faecal microbial diversity was significantly negatively correlated with the Hospital Anxiety and Depression scale (P < 0.05). CONCLUSIONS: We present data that distinguishes the intestinal microbiota of PI-IBS patients from that of both general IBS patients and HC. The microbial composition is significantly associated with the HADs score and alterations in lymphocyte subsets proportions.

Application of the Human Intestinal Tract Chip to the non-human primate gut microbiota.

The human intestinal microbiota is responsible for various health-related functions, and its diversity can be readily mapped with the 16S ribosomal RNA targeting Human Intestinal Tract (HIT) Chip. Here we characterise distal gut samples from chimpanzees, gorillas and marmosets, and compare them with human gut samples. Our results indicated applicability of the HITChip platform can be extended to chimpanzee and gorilla faecal samples for analysis of microbiota composition and enterotypes, but not to the evolutionary more distant marmosets.