Home About us Contact
|
Home About us Contact | ||
|
|
||
Gut Microbiota (gut + microbiota)
Selected AbstractsQuantitative, longitudinal profiling of the primate fecal microbiota reveals idiosyncratic, dynamic communitiesENVIRONMENTAL MICROBIOLOGY, Issue 3 2006Joy Wireman Summary We used slot blot hybridization, quantitative polymerase chain reaction (qPCR), and flow cytometry microarrays to quantify specific 16S rDNAs in weekly fecal specimens from four monkeys housed in a research vivarium for periods ranging from five to 8 months. Even in these uniformly housed and fed animals the gut microbiota is idiosyncratic, very dynamic on short timescales, and shows significant positive and negative correlations among some bacteria as well as responses to heavy metal exposure. The relative quantification (fmol targets per total fmol bacterial 16S rDNA) afforded by flow cytometry microarrays agreed well with the absolute quantification (nanogram of target DNA per nanogram of fecal DNA) afforded by slot blots and qPCR. We also noted strengths and weaknesses in inter-method comparisons for DNA-based quantification of these complex bacterial communities. [source] A review on the interactions between gut microbiota and innate immunity of fishFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2008Geovanny D. Gómez Abstract Although fish immunology has progressed in the last few years, the contribution of the normal endogenous microbiota to the overall health status has been so far underestimated. In this context, the establishment of a normal or protective microbiota constitutes a key component to maintain good health, through competitive exclusion mechanisms, and has implications for the development and maturation of the immune system. The normal microbiota influences the innate immune system, which is of vital importance for the disease resistance of fish and is divided into physical barriers, humoral and cellular components. Innate humoral parameters include antimicrobial peptides, lysozyme, complement components, transferrin, pentraxins, lectins, antiproteases and natural antibodies, whereas nonspecific cytotoxic cells and phagocytes (monocytes/macrophages and neutrophils) constitute innate cellular immune effectors. Cytokines are an integral component of the adaptive and innate immune response, particularly IL-1,, interferon, tumor necrosis factor-,, transforming growth factor-, and several chemokines regulate innate immunity. This review covers the innate immune mechanisms of protection against pathogens, in relation with the installation and composition of the normal endogenous microbiota in fish and its role on health. Knowledge of such interaction may offer novel and useful means designing adequate therapeutic strategies for disease prevention and treatment. [source] Abundance, diversity, and activity of microbial assemblages associated with coral reef fish guts and fecesFEMS MICROBIOLOGY ECOLOGY, Issue 1 2010Steven Smriga Abstract Feces and distal gut contents were collected from three coral reef fish species. Bacteria cell abundances, as determined via epifluorescence microscopy, ranged two orders of magnitude among the fishes. Mass-specific and apparent cell-specific hydrolytic enzyme activities in feces from Chlorurus sordidus were very high, suggesting that endogenous fish enzymes were egested into feces. Denaturing gradient gel electrophoresis profiles of 16S rRNA genes were more similar among multiple individuals of the surgeonfish Acanthurus nigricans than among individuals of the parrotfish C. sordidus or the snapper Lutjanus bohar. Analyses of feces-derived 16S rRNA gene clones revealed that at least five bacterial phyla were present in A. nigricans and that Vibrionaceae comprised 10% of the clones. Meanwhile, C. sordidus contained at least five phyla and L. bohar three, but Vibrionaceae comprised 71% and 76% of the clones, respectively. Many sequences clustered phylogenetically to cultured Vibrio spp. and Photobacterium spp. including Vibrio ponticus and Photobacterium damselae. Other Vibrionaceae -like sequences comprised a distinct phylogenetic group that may represent the presence of ,feces-specific' bacteria. The observed differences among fishes may reflect native gut microbiota and/or bacterial assemblages associated with ingested prey. [source] Bacteria,diet interactions affect longevity in the medfly ,Ceratitis capitataJOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2008M. Ben-Yosef Abstract Mediterranean fruit flies (Ceratitis capitata Wiedemann, Dipt.: Tephritidae) harbour a diverse community of bacteria in their digestive system. This microbiota may have important functions impacting on the fly's fitness. Recently, we described the effect of eliminating intestinal bacteria on the reproductive success of C. capitata males and females. Here, we expand the view on the nature of fly,bacteria interactions by examining the effect of bacteria on male and female longevity. Antibiotics were used to suppress the gut bacterial community and mortality rates were compared between antibiotic-treated and non-treated flies when either nutritionally stressed (maintained on sugar) or provided with a full diet. These tests revealed that eliminating the gut bacterial population prolonged longevity, but only when flies were nutritionally stressed, indicating that the effect of bacteria on lifespan was diet dependent. Considering these results in light of other known effects of bacteria on fitness components of the fly demonstrates a cost-benefit relationship between C. capitata and its gut microbiota. [source] The effect of Pediococcus acidilactici on the gut microbiota and immune status of on-growing red tilapia (Oreochromis niloticus)JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2010R.M.W. Ferguson Abstract Aim:, To assess Pediococcus acidilactici as a dietary supplement for on-growing red tilapia (Oreochromis niloticus). Methods and Results:, Tilapia were fed either a control diet or control diet supplemented with Ped. acidilactici at 107 CFU g,1 for 32 days. Ped. acidilactici colonized the intestinal tract and significantly affected the intestinal microbial communities. PCR-DGGE revealed direct antagonism of gastric Ped. acidilactici with an endogenous uncultured bacterium during a period of reverting to nonsupplemented feeding. Light microscopy revealed that gut integrity and leucocyte levels were unaffected by Ped. acidilactici; however, blood leucocyte levels and serum lysozyme activity were elevated after 14-days' feeding. No significant improvements in growth performance were observed at the end of the trial (day 32), but survival was significantly higher in the probiotic group. Conclusions:, The study demonstrates that oral supplementation of Ped. acidilactici modulates intestinal bacterial communities in on-growing red tilapia and also stimulates some aspects of the nonspecific immune response. Significance and Impact of the study:, To our knowledge this is the first study assessing the effects of probiotics on the gut microbiota of tilapia using culture-independent methods. Such methods are crucial to understand the mechanisms which underpin and mediate host benefits. [source] Development and validation of a ultra performance LC-ESI/MS method for analysis of metabolic phenotypes of healthy men in day and night urine samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 16-17 2008Xijun Wang Abstract Ultra-performance LC coupled to quadrupole TOF/MS (UPLC-QTOF/MS) in positive and negative ESI was developed and validated to analyze metabolite profiles for urine from healthy men during the day and at night. Data analysis using principal components analysis (PCA) revealed differences between metabolic phenotypes of urine in healthy men during the day and at night. Positive ions with mass-to-charge ratio (m/z) 310.24 (5.35 min), 286.24 (4.74 min) and 310.24 (5.63 min) were elevated in the urine from healthy men at night compared to that during the day. Negative ions elevated in day urine samples of healthy men included m/z 167.02 (0.66 min), 263.12 (2.55 min) and 191.03 (0.73 min), whilst ions m/z 212.01 (4.77 min) were at a lower concentration in urine of healthy men during the day compared to that at night. The ions m/z 212.01 (4.77 min), 191.03 (0.73 min) and 310.24 (5.35 min) preliminarily correspond to indoxyl sulfate, citric acid and N -acetylneuraminic acid, providing further support for an involvement of phenotypic difference in urine of healthy men in day and night samples, which may be associated with notably different activities of gut microbiota, velocity of tricarboxylic acid cycle and activity of sialic acid biosynthesis in healthy men as regulated by circadian rhythm of the mammalian bioclock. [source] Review article: prebiotics in the gastrointestinal tractALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2006S. MACFARLANE Summary Background Prebiotics are short-chain carbohydrates that alter the composition, or metabolism, of the gut microbiota in a beneficial manner. It is therefore expected that prebiotics will improve health in a way similar to probiotics, whilst at the same time being cheaper, and carrying less risk and being easier to incorporate into the diet than probiotics. Aim To review published evidence for prebiotic effects on gut function and human health. Methods We searched the Science Citation Index with the terms prebiotic, microbiota, gut bacteria, large intestine, mucosa, bowel habit, constipation, diarrhoea, inflammatory bowel disease, Crohn's disease, ulcerative colitis, pouchitis, calcium and cancer, focussing principally on studies in humans and reports in the English language. Search of the Cochrane Library did not identify any clinical study or meta-analysis on this topic. Results Three prebiotics, oligofructose, galacto-oligosaccharides and lactulose, clearly alter the balance of the large bowel microbiota by increasing bifidobacteria and Lactobacillus numbers. These carbohydrates are fermented and give rise to short-chain fatty acid and intestinal gas; however, effects on bowel habit are relatively small. Randomized-controlled trials of their effect in a clinical context are few, although animal studies show anti-inflammatory effects in inflammatory bowel disease, while calcium absorption is increased. Conclusions It is still early days for prebiotics, but they offer the potential to modify the gut microbial balance in such a way as to bring direct health benefits cheaply and safely. [source] Development of a real-time PCR method for Firmicutes and Bacteroidetes in faeces and its application to quantify intestinal population of obese and lean pigsLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2008X. Guo Abstract Aims:, To investigate whether the relative abundance of the Bacteroidetes and Firmicutes divisions in pigs is different between obese and lean animals. Methods and Results:, Group-specific primers were designed to target the 16S rRNA genes of Bacteroidetes and Firmicutes present in the gut. After the validation of their specificity, these primers were used in the real-time PCR quantification of all Bacteria, Firmicutes division, Bacteroidetes division and Bacteroides spp. in the faecal samples of obese and lean pigs from Banna mini-pig inbred line. The obese pigs had a ,61% fewer percentage (based on all Bacteria) of Bacteroidetes division (P = 0·033) and a ,56% fewer proportion of Bacteroides spp. (P = 0·047) than the lean pigs. The proportions of both Bacteroidetes and Bacteroides had a negative correlation (P < 0·01) with the body weight. Conclusion:, The results suggested that the fat storage might affect the proportion of Bacteroidetes division in the gut. Significance and Impact of the Study:, The real-time PCR assays developed for Firmicutes and Bacteroidetes will be useful for investigating the composition of gut microbiota. [source] The role of the intestinal microbiota in the development of atopic disordersALLERGY, Issue 11 2007J. Penders The prevalence of atopic diseases, including eczema, allergic rhinoconjunctivitis and asthma, has increased worldwide, predominantly in westernized countries. Recent epidemiological studies and experimental research suggest that microbial stimulation of the immune system influences the development of tolerance to innocuous allergens. The gastrointestinal microbiota composition may be of particular interest, as it provides an early and major source of immune stimulation and seems to be a prerequisite for the development of oral tolerance. In this review the observational studies of the association between the gut microbiota and atopic diseases are discussed. Although most studies indicated an association between the gut microbiota composition and atopic sensitization or symptoms, no specific harmful or protective microbes can be identified yet. Some important methodological issues that have to be considered are the microbiological methods used (traditional culture vs molecular techniques), the timing of examining the gut microbiota, the definition of atopic outcomes, confounding and reverse causation. In conclusion, the microbiota hypothesis in atopic diseases is promising and deserves further attention. To gain more insight into the role of the gut microbiota in the etiology of atopy, large-scale prospective birth cohort studies using molecular methods to study the gut microbiota are needed. [source] Metabolism of Maillard reaction products by the human gut microbiota , implications for healthMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 9 2006Kieran M. Tuohy Abstract The human colonic microbiota imparts metabolic versatility on the colon, interacts at many levels in healthy intestinal and systemic metabolism, and plays protective roles in chronic disease and acute infection. Colonic bacterial metabolism is largely dependant on dietary residues from the upper gut. Carbohydrates, resistant to digestion, drive colonic bacterial fermentation and the resulting end products are considered beneficial. Many colonic species ferment proteins but the end products are not always beneficial and include toxic compounds, such as amines and phenols. Most components of a typical Western diet are heat processed. The Maillard reaction, involving food protein and sugar, is a complex network of reactions occurring during thermal processing. The resultant modified protein resists digestion in the small intestine but is available for colonic bacterial fermentation. Little is known about the fate of the modified protein but some Maillard reaction products (MRP) are biologically active by, e. g. altering bacterial population levels within the colon or, upon absorption, interacting with human disease mechanisms by induction of inflammatory responses. This review presents current understanding of the interactions between MRP and intestinal bacteria. Recent scientific advances offering the possibility of elucidating the consequences of microbe-MRP interactions within the gut are discussed. [source] Altered intestinal microbiota in irritable bowel syndromeNEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2010K. J. Lee Abstract, Recent studies have suggested that alterations in the composition of the intestinal microbiota may play an important role in irritable bowel syndrome (IBS) symptoms. However, an association between the composition of the intestinal microbiota and IBS symptoms has not been clearly demonstrated. In the current issue of the Journal, Tana et al. suggest that altered intestinal microbiota contributes to the symptoms of IBS through increased levels of organic acids. In fecal samples, IBS patients had significantly higher numbers of Veillonella and Lactobacillus than healthy controls. They also showed significantly higher levels of acetic acid and propionic acid. Furthermore, IBS patients with high acetic acid or propionic acid levels presented more severe symptoms, impaired quality of life and negative emotions. These results are in accordance with the concept that the gut microbiota influences the sensory, motor and immune system of the gut and interacts with higher brain centers. Small intestinal bacterial overgrowth observed in a subset of IBS patients describes quantitative changes in the small intestinal microbiota. Data on qualitative changes in the gut microbiota in IBS patients are lacking. Different members of gut bacteria may have different influence on gut function. The concepts identified here may lead to the development of novel therapeutic strategies for IBS using manipulation of the intestinal microbiota. [source] Prebiotics in aquaculture: a reviewAQUACULTURE NUTRITION, Issue 2 2010E. RINGØ Abstract A prebiotic is a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or the activity of one or a limited number of bacteria in the colon. Despite the potential benefits to health and performance as noted in various terrestrial animals, the use of prebiotics in the farming of fish and shellfish has been less investigated. The studies of prebiotics in fish and shellfish have investigated the following parameters: effect on growth, feed conversion, gut microbiota, cell damage/morphology, resistance against pathogenic bacteria and innate immune parameters such as alternative complement activity (ACH50), lysozyme activity, natural haemagglutination activity, respiratory burst, superoxide dismutase activity and phagocytic activity. This review discusses the results from these studies and the methods used. If the use of prebiotics leads to health responses becoming more clearly manifested in fish and shellfish, then prebiotics might have the potential to increase the efficiency and sustainability of aquaculture production. However, large gaps of knowledge exist. To fully conclude on the effects of adding prebiotics in fish diets, more research efforts are needed to provide the aquaculture industry, the scientific community, the regulatory bodies and the general public with the necessary information and tools. [source] Establishment of the gut microbiota in Western infantsACTA PAEDIATRICA, Issue 2 2009I Adlerberth Abstract In adult individuals, the intestinal microbiota comprises several hundred, mostly anaerobic, bacterial species. This complex ecosystem is formed through the successive establishment of different bacteria in infancy and early childhood. Facultative and aerotolerant bacteria establish first, followed by more and more strict anaerobes. The bacteria derive from different sources and the colonization pattern is influenced by delivery mode and environmental factors. Commensal microbes provide the major drive for maturation of the immune system. Increased hygiene appears to have changed the gut flora of Western infants, which may affect the risk of developing immune mediated diseases. Conclusion: It is clear that the process of infant colonization needs to be studied further, since composition of the microbiota may impact on child health. [source] Altered early infant gut microbiota in children developing allergy up to 5 years of ageCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2009Y. M. Sjögren Summary Background Early colonization with bifidobacteria and lactobacilli is postulated to protect children from allergy, while Clostridium (C.) difficile colonization might be associated with allergic disease. Previous studies of infant gut microbiota in relation to subsequent allergy development have mostly employed culture-dependent techniques, studied genera of bacteria and the follow-up period was limited to 2 years. Objective To relate gut microbiota in early infancy, notably bifidobacteria and lactobacilli at species level, to allergy development during the first 5 years of life and study if environmental factors influence the early infant gut microbiota. Methods Fecal samples were collected at 1 week, 1 month and 2 months after birth from 47 Swedish infants, followed prospectively to 5 years of age. Bacterial DNA was analysed with real-time PCR and related to allergy development, family size as well as endotoxin and Fel d 1 levels in house dust samples. Primers binding to C. difficile, four species of bifidobacteria, two lactobacilli groups and Bacteroides fragilis were used. Children regarded as allergic manifested allergic symptoms and were skin prick test positive during their first 5 years while non-allergic children were neither. Results Children who developed allergy were significantly less often colonized with lactobacilli group I (Lactobacillus (L.) rhamnosus, L. casei, L. paracasei), Bifidobacterium adolescentis and C. difficile during their first 2 months. Infants colonized with several Bifidobacterium species had been exposed to higher amounts of endotoxin and grew up in larger families than infants harbouring few species. Conclusion A more diverse gut microbiota early in life might prevent allergy development and may be related to the previously suggested inverse relationship between allergy, family size and endotoxin exposure. [source] | |||||||||||||||||||||||||