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1

Small intestinal bacterial overgrowth.  

PubMed

Small intestinal bacterial overgrowth (SIBO) syndrome is characterized in its florid form by diarrhoea and weight loss. The most common underlying factors are dysmotility, small intestinal obstruction, blind or afferent loops. Small intestinal bacterial overgrowth can be diagnosed by: 1) culture of jejunum aspirate for bacterial counts, 2) 14C-D-xylose breath testing, 3) non-invasive hydrogen breath testing using glucose or lactulose or 4) 14C-glycocholic acid breath testing. The treatment usually consists of the eradication of bacterial overgrowth with repeated course of antimicrobials, correction of associated nutritional deficiencies and, when possible, correction of the underlying predisposing conditions. PMID:18609165

Rana, S V; Bhardwaj, S B

2008-01-01

2

Small Intestinal Bacterial Overgrowth  

PubMed Central

Small intestinal bacterial overgrowth (SIBO), defined as excessive bacteria in the small intestine, remains a poorly understood disease. Initially thought to occur in only a small number of patients, it is now apparent that this disorder is more prevalent than previously thought. Patients with SIBO vary in presentation, from being only mildly symptomatic to suffering from chronic diarrhea, weight loss, and malabsorption. A number of diagnostic tests are currently available, although the optimal treatment regimen remains elusive. Recently there has been renewed interest in SIBO and its putative association with irritable bowel syndrome. In this comprehensive review, we will discuss the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of SIBO.

Dukowicz, Andrew C.; Levine, Gary M.

2007-01-01

3

Small intestinal bacterial overgrowth in human cirrhosis is associated with systemic endotoxemia  

Microsoft Academic Search

OBJECTIVES:Systemic endotoxemia has been implicated in various pathophysiological sequelae of chronic liver disease. One of its potential causes is increased intestinal absorption of endotoxin. We therefore examined the association of small intestinal bacterial overgrowth with systemic endotoxemia in patients with cirrhosis.METHODS:Fifty-three consecutive patients with cirrhosis (Child-Pugh group A, 23; group B, 18; group C, 12) were included. Jejunal secretions were

Tilman M Bauer; Henning Schwacha; Bernhard Steinbrückner; Folke E Brinkmann; Anette K Ditzen; John J Aponte; Klaus Pelz; Dieter Berger; Manfred Kist; Hubert E Blum

2002-01-01

4

Intestinal epithelial defense systems protect against bacterial threats  

Microsoft Academic Search

Numerous bacterial species inhabit the lumen of the human intestine. The epithelial cells that line the intestinal barrier\\u000a are in direct contact with many of these species and have developed sophisticated strategies to prevent bacterial invasion\\u000a of host tissue beyond simply providing a physical blockade. Intestinal epithelial cells (IECs) possess receptors that are\\u000a capable of recognizing bacterial products, and engagement

Bryan P. Hurley; Beth A. McCormick

2004-01-01

5

Small Intestinal Bacterial Overgrowth: Diagnosis and Treatment  

Microsoft Academic Search

Small intestinal bacterial overgrowth (SIBO) is a clinical condition characterized by a malabsorption syndrome due to an increase in microorganisms within the small intestine. The main mechanisms restricting bacterial colonization in the upper gut are the gastric acid barrier, mucosal and systemic immunity and intestinal clearance. When these mechanisms fail, bacterial overgrowth develops. Diarrhea, steatorrhea, chronic abdominal pain, bloating and

Antonio Gasbarrini; Maurizio Gabrielli; Emidio Scarpellini; Andrea Lupascu; Veronica Ojetti; Giovanni Gasbarrini

2007-01-01

6

Mucin Dynamics in Intestinal Bacterial Infection  

PubMed Central

Background Bacterial gastroenteritis causes morbidity and mortality in humans worldwide. Murine Citrobacter rodentium infection is a model for gastroenteritis caused by the human pathogens enteropathogenic Escherichia coli and enterohaemorrhagic E. coli. Mucin glycoproteins are the main component of the first barrier that bacteria encounter in the intestinal tract. Methodology/Principal Findings Using Immunohistochemistry, we investigated intestinal expression of mucins (Alcian blue/PAS, Muc1, Muc2, Muc4, Muc5AC, Muc13 and Muc3/17) in healthy and C. rodentium infected mice. The majority of the C. rodentium infected mice developed systemic infection and colitis in the mid and distal colon by day 12. C. rodentium bound to the major secreted mucin, Muc2, in vitro, and high numbers of bacteria were found in secreted MUC2 in infected animals in vivo, indicating that mucins may limit bacterial access to the epithelial surface. In the small intestine, caecum and proximal colon, the mucin expression was similar in infected and non-infected animals. In the distal colonic epithelium, all secreted and cell surface mucins decreased with the exception of the Muc1 cell surface mucin which increased after infection (p<0.05). Similarly, during human infection Salmonella St Paul, Campylobacter jejuni and Clostridium difficile induced MUC1 in the colon. Conclusion Major changes in both the cell-surface and secreted mucins occur in response to intestinal infection.

Linden, Sara K.; Florin, Timothy H. J.; McGuckin, Michael A.

2008-01-01

7

Reduction of azo dyes and nitroaromatic compounds by bacterial enzymes from the human intestinal tract.  

PubMed Central

Several anaerobic bacteria from the human intestinal tract are capable of reducing azo dyes and nitropolycyclic aromatic hydrocarbons to the corresponding aromatic amines with enzymes that have azoreductase and nitroreductase activities. The majority of bacteria with these activities belong to the genera Clostridium and Eubacterium. The azoreductases and nitroreductases from three Clostridium strains and one Eubacterium strain were studied. Both enzymes were produced constitutively in each of the bacteria; the enzymes from various bacteria had different electrophoretic mobilities. The azoreductases from all of the bacteria had immunological homology, as was evident from the cross-reactivity of an antibody raised against the azoreductase of C. perfringens with azoreductases from other bacteria. Comparison of azoreductases and nitroreductases showed that they both had identical electrophoretic mobilities on polyacrylamide gels and reacted with the antibody against the azoreductase from C. perfringens. Furthermore, the nitroaromatic compounds competitively inhibited the azoreductase activity. The data indicate that the reduction of both nitroaromatic compounds and azo dyes may be carried out by the same enzyme, which is possibly a flavin adenine dinucleotide dehydrogenase that is synthesized throughout the cell and not associated with any organized subcellular structure. Images Figure 1.

Rafii, F; Cerniglia, C E

1995-01-01

8

Synergy between bacterial infection and genetic predisposition in intestinal dysplasia.  

PubMed

Accumulating evidence suggests that hyperproliferating intestinal stem cells (SCs) and progenitors drive cancer initiation, maintenance, and metastasis. In addition, chronic inflammation and infection have been increasingly recognized for their roles in cancer. Nevertheless, the mechanisms by which bacterial infections can initiate SC-mediated tumorigenesis remain elusive. Using a Drosophila model of gut pathogenesis, we show that intestinal infection with Pseudomonas aeruginosa, a human opportunistic bacterial pathogen, activates the c-Jun N-terminal kinase (JNK) pathway, a hallmark of the host stress response. This, in turn, causes apoptosis of enterocytes, the largest class of differentiated intestinal cells, and promotes a dramatic proliferation of SCs and progenitors that serves as a homeostatic compensatory mechanism to replenish the apoptotic enterocytes. However, we find that this homeostatic mechanism can lead to massive over-proliferation of intestinal cells when infection occurs in animals with a latent oncogenic form of the Ras1 oncogene. The affected intestines develop excess layers of cells with altered apicobasal polarity reminiscent of dysplasia, suggesting that infection can directly synergize with the genetic background in predisposed individuals to initiate SC-mediated tumorigenesis. Our results provide a framework for the study of intestinal bacterial infections and their effects on undifferentiated and mature enteric epithelial cells in the initial stages of intestinal cancer. Assessment of progenitor cell responses to pathogenic intestinal bacteria could provide a measure of predisposition for apoptotic enterocyte-assisted intestinal dysplasias in humans. PMID:19934041

Apidianakis, Yiorgos; Pitsouli, Chrysoula; Perrimon, Norbert; Rahme, Laurence

2009-12-01

9

Small intestinal bacterial overgrowth: diagnosis and treatment.  

PubMed

Small intestinal bacterial overgrowth (SIBO) is a clinical condition characterized by a malabsorption syndrome due to an increase in microorganisms within the small intestine. The main mechanisms restricting bacterial colonization in the upper gut are the gastric acid barrier, mucosal and systemic immunity and intestinal clearance. When these mechanisms fail, bacterial overgrowth develops. Diarrhea, steatorrhea, chronic abdominal pain, bloating and flatulence are common symptoms and are similar to those observed in irritable bowel syndrome. Breath tests (glucose and/or lactulose breath tests) have been proposed as a sensitive and simple tool for the diagnosis of bacterial overgrowth, being non-invasive and inexpensive compared to the gold standard represented by the culture of intestinal aspirates. Antibiotic therapy is the cornerstone of SIBO treatment. Current SIBO treatment is based on empirical courses of broad-spectrum antibiotics since few controlled studies concerning the choice and duration of antibiotic therapy are available at present. PMID:17827947

Gasbarrini, Antonio; Lauritano, Ernesto Cristiano; Gabrielli, Maurizio; Scarpellini, Emidio; Lupascu, Andrea; Ojetti, Veronica; Gasbarrini, Giovanni

2007-01-01

10

Association between Hypothyroidism and Small Intestinal Bacterial Overgrowth  

Microsoft Academic Search

Objectives: Small intestinal bacterial overgrowth is defined as an abnormally high bacterial population level in the small intestine. Intestinal motor dysfunction associated with hypothyroidism could predispose to bacterial overgrowth. Luminal bacteria could modulate gastrointestinal symptoms and interfere with levothyroxine absorp- tion. The aims of the present study were to assess the prevalence and clinical pattern of bacterial overgrowth in patients

Ernesto Cristiano Lauritano; Anna Lisa Bilotta; Maurizio Gabrielli; Emidio Scarpellini; Andrea Lupascu; Antonio Laginestra; Marialuisa Novi; Sandra Sottili; Michele Serricchio; Giovanni Cammarota; Giovanni Gasbarrini; Alfredo Pontecorvi; Antonio Gasbarrini

11

Protection from intestinal inflammation by bacterial exopolysaccharides.  

PubMed

Host inflammatory responses against pathogenic organisms can be abrogated by commensals; however, the molecular mechanisms by which pathogenesis is prevented are still poorly understood. Previous studies demonstrated that administration of a single dose of Bacillus subtilis prevented disease and inflammation by the enteric mouse pathogen Citrobacter rodentium, which causes disease similar to the human pathogen enteropathogenic Escherichia coli. No protection was observed when an exopolysaccharide (EPS)-deficient mutant of B. subtilis was used, suggesting that EPS are the protective factor. In this study, we isolated and characterized EPS and showed that they also prevent C. rodentium-associated intestinal disease after a single injection. Protection is TLR4 dependent because EPS-treated TLR4 knockout mice developed disease. Furthermore, protection could be conveyed to wild-type mice by adoptive transfer of macrophage-rich peritoneal cells from EPS-treated mice. We found that EPS specifically bind peritoneal macrophages, and because mice lacking MyD88 signaling in myeloid cells were not protected by EPS, we conclude that bacterial EPS prevent colitis in a TLR4-dependent manner that requires myeloid cells. These studies provide a simple means of preventing intestinal inflammation caused by enteric pathogens. PMID:24740503

Jones, Sara E; Paynich, Mallory L; Kearns, Daniel B; Knight, Katherine L

2014-05-15

12

Prevalence of Intestinal Parasitic and Bacterial Pathogens in Diarrhoeal and Non-diarroeal Human Stools from Vhembe District, South Africa  

PubMed Central

In the present study, a cross-sectional survey of intestinal parasitic and bacterial infections in relation to diarrhoea in Vhembe district and the antimicrobial susceptibility profiles of isolated bacterial pathogens was conducted. Stool samples were collected from 528 patients attending major public hospitals and 295 children attending two public primary schools and were analyzed by standard microbiological and parasitological techniques. Entamoeba histolytica/E. dispar (34.2%) and Cryptosporidium spp. (25.5%) were the most common parasitic causes of diarrhoea among the hospital attendees while Giardia lamblia (12.8%) was the most common cause of diarrhoea among the primary school children (p<0.05). Schistosoma mansoni (14.4%) was more common in non-diarrhoeal samples at both hospitals (16.9%) and schools (17.6%). Campylobacter spp. (24.9%), Aeromonas spp. (20.8%), and Shigella spp. (8.5%) were the most common bacterial causes of diarrhoea among the hospital attendees while Campylobacter (12.8%) and Aeromonas spp. (12.8%) were most common in diarrhoeal samples from school children. Vibrio spp. was less common (3% in the hospitals) and were all associated with diarrhoea. Antimicrobial resistance was common among the bacterial isolates but ceftriaxone (91%) and ciprofloxacin (88.6%) showed stronger activities against all the organisms. The present study has demonstrated that E. histolytica/dispar, Cryptosporidium, Giardia, and Cyclospora are common parasitic causes of diarrhoea in Vhembe district while Campylobacter spp. and Aeromonas are the most common bacterial causes of diarrhoea in Vhembe district of South Africa.

Guerrant, R.L.; Barrett, L.; Bessong, P.O.; Igumbor, E.O.; Obi, C.L.

2009-01-01

13

Small Intestinal Bacterial Overgrowth: Roles of Antibiotics, Prebiotics, and Probiotics  

Microsoft Academic Search

Small intestinal bacterial overgrowth is common in in- testinal failure. Its occurrence relates to alterations in intestinal anatomy, motility, and gastric acid secretion. Its presence may contribute to symptoms, mucosal in- jury, and malnutrition. Relationships between bacterial overgrowth and systemic sepsis are of potential impor- tance in the intestinal failure patient because the direct translocation of bacteria across the intestinal

EAMONN M. M. QUIGLEY; RODRIGO QUERA

14

Campylobacter jejuni Outer Membrane Vesicles Play an Important Role in Bacterial Interactions with Human Intestinal Epithelial Cells  

PubMed Central

Campylobacter jejuni is the most prevalent cause of food-borne gastroenteritis in the developed world; however, the molecular basis of pathogenesis is unclear. Secretion of virulence factors is a key mechanism by which enteric bacterial pathogens interact with host cells to enhance survival and/or damage the host. However, C. jejuni lacks the virulence-associated secretion systems possessed by other enteric pathogens. Many bacterial pathogens utilize outer membrane vesicles (OMVs) for delivery of virulence factors into host cells. In the absence of prototypical virulence-associated secretion systems, OMVs could be an important alternative for the coordinated delivery of C. jejuni proteins into host cells. Proteomic analysis of C. jejuni 11168H OMVs identified 151 proteins, including periplasmic and outer membrane-associated proteins, but also many determinants known to be important in survival and pathogenesis, including the cytolethal distending toxin (CDT). C. jejuni OMVs contained 16 N-linked glycoproteins, indicating a delivery mechanism by which these periplasm-located yet immunogenic glycoproteins can interact with host cells. C. jejuni OMVs possess cytotoxic activity and induce a host immune response from T84 intestinal epithelial cells (IECs), which was not reduced by OMV pretreatment with proteinase K or polymyxin B prior to coincubation with IECs. Pretreatment of IECs with methyl-beta-cyclodextrin partially blocks OMV-induced host immune responses, indicating a role for lipid rafts in host cell plasma membranes during interactions with C. jejuni OMVs. OMVs isolated from a C. jejuni 11168H cdtA mutant induced interleukin-8 (IL-8) to the same extent as did wild-type OMVs, suggesting OMV induction of IL-8 is independent of CDT.

Elmi, Abdi; Watson, Eleanor; Sandu, Pamela; Gundogdu, Ozan; Mills, Dominic C.; Inglis, Neil F.; Manson, Erin; Imrie, Lisa; Bajaj-Elliott, Mona; Wren, Brendan W.; Smith, David G. E.

2012-01-01

15

Expression of Toll-like receptor 9 and response to bacterial CpG oligodeoxynucleotides in human intestinal epithelium*  

PubMed Central

Recognition of repeat CpG motifs, which are common in bacterial, but not in mammalian, DNA, through Toll-like receptor (TLR)9 is an integral part of the innate immune system. As the role of TLR9 in the human gut is unknown, we determined the spectrum of TLR9 expression in normal and inflamed colon and examined how epithelial cells respond to specific TLR9 ligand stimulation. TLR9 expresssion was measured in human colonic mucosal biopsies, freshly isolated human colonic epithelial cells and HT-29 cells by reverse transcriptase-polymerase chain reaction or Western blotting. Colonic epithelial cell cultures were stimulated with a synthetic CpG-oligodeoxynucleotide (ODN), exhibiting strong immunostimulatory effects in B cells. Interleukin (IL)-8 secretion was determined by enzyme-linked immunosorbent assay, nuclear factor-kappaB (NF-kB) activity by electrophoretic mobility shift assay and IkB phosphorylation by Western blotting. TLR9 mRNA was equally expressed in colonic mucosa from controls (n = 6) and patients with ulcerative colitis or Crohn's disease disease (n = 13). HT-29 cells expressed TLR9 mRNA and protein and responded to CpG-ODN (P < 0·01), but not to non-CpG-ODN stimulation, by secreting IL-8, apparently in the absence of NF-kB activation. Primary epithelial cells isolated from normal human colon expressed TLR9 mRNA, but were completely unresponsive to CpG-ODN stimulation in vitro. In conclusion, differentiated human colonic epithelial cells are unresponsive to TLR9 ligand stimulation in vitro despite spontaneous TLR9 gene expression. This suggests that the human epithelium is able to avoid inappropriate immune responses to luminal bacterial products through modulation of the TLR9 pathway.

Pedersen, G; Andresen, L; Matthiessen, M W; Rask-Madsen, J; Brynskov, J

2005-01-01

16

Human milk oligosaccharide consumption by intestinal microbiota  

PubMed Central

Human milk oligosaccharides (HMO) constitute the third most abundant class of molecules in breast milk. Since infants lack the enzymes required for milk glycan digestion, this group of carbohydrates passes undigested to the lower part of the intestinal tract, where they can be consumed by specific members of the infant gut microbiota. We review proposed mechanisms for the depletion and metabolism of HMO by two major bacterial genera within the infant intestinal microbiota, Bifidobacterium and Bacteroides

Marcobal, A.; Sonnenburg, J. L.

2013-01-01

17

Bacterial toxin interaction with the developing intestine.  

PubMed

An important approach to the major health problem of bacterial infection in young children has been to examine bacterial toxin binding to microvillus membrane receptors, the signal transduction produced by that interaction and the mechanisms of fluid secretion in the developing intestine as a basis for toxigenic diarrhea in the infant population. These studies indicate that receptor binding and effector responses may be subjected to developmental regulation. This regulation process of toxin interaction with the developing intestine may have an enhanced or harmful effect or, under some circumstances, may have a beneficial effect and be protective to the vulnerable child. Specific mechanisms for the developmental control of receptor expression may involve the regulation of individual glycosyltransferases responsible for the addition of receptor sugar sequences to glycolipids and/or glycoproteins, presumably at the transcriptional level. Furthermore, although highly speculative at this point, the differential expression of signal transducers (e.g., guanine nucleotide-regulatory proteins or G proteins) and ion transporters (e.g., Na+,K(+)-stimulated adenosine triphosphatase, the Cl- channels, etc.) during development may also alter the neonatal host's responsiveness. Therefore, the developmental control of microvillus membrane receptors, signal transduction mechanisms, and ion transport systems in the gastro-intestinal tract may in part contribute to the altered host sensitivity in toxigenic diarrhea of infancy. PMID:8382647

Chu, S H; Walker, W A

1993-03-01

18

Diversity of the Human Intestinal Microbial Flora  

Microsoft Academic Search

The human endogenous intestinal microflora is an essential ``organ'' in providing nourishment, regulating epithelial development, and instructing innate immunity; yet, surprisingly, basic features remain poorly described. We examined 13,355 prokaryotic ribosomal RNA gene sequences from multiple colonic mucosal sites and feces of healthy subjects to improve our understanding of gut microbial diversity. A majority of the bacterial sequences corresponded to

Paul B. Eckburg; Elisabeth M. Bik; Charles N. Bernstein; Elizabeth Purdom; Les Dethlefsen; Michael Sargent; Steven R. Gill; Karen E. Nelson; David A. Relman

2005-01-01

19

[Human intestinal spirochetosis].  

PubMed

A characteristic feature of human intestinal spirochetosis (IS) is the colonization of the mucosa of the large intestine with intestinal spirochetes of the genus Brachyspira. The joining of the brachyspirae with the apical cellular membrane of enterocytes resembles in histological slides a false brush border of the intestinal mucosa. Various symptoms related to the involvement of the large gut were found with invasive IS. From the cultures of these cases were isolated Brachyspira aalborgii and B. pilosicoli. The frequency of the incidence of brachyspirae depended on the socio-economic living conditions of people. Colonization of the mucosa of the large gut was found more often in human populations in the developing countries; it was fairly rare in countries with high hygienic standards. An exception were men of homosexual orienation and patients presenting with a HIV infection. Isolation of brachyspirae from the faeces and biopsy of the mucosa of the large gut are fairly demanding jobs, especially with B. aalborgii. Most documented IS cases of this aetiology were diagnosed using immunohistochemical methods and amplification of the genus-specific region of the gene 16S rRNA. Isolation of B. pilosicoli tends to be simpler, it requires anaerobic incubation on selective blood agars for a period of 3-6 days at 37 degrees C. When manual haemoculture systems were used, patients in a critical state presented a translocation of brachyspirae into blood circulation, while automatic systems don't necessarily diagnose spirochetaemia. In the management of described cases of invasive IS particularly successful proved metronidazole and beta-lactam antibiotics. In isolated B. pilosicoli, in vitro tests confirmed sensitivity to metronidazole, ceftriaxone, meropenem, tetracycline, moxifloxacine and chloramphenicol. A varying frequency of resistance was found with clindamycin and amoxicillin, which how ever was efficacious in combination with clavulanic acid. PMID:15146383

Cízek, Alois; Lobová, Dana

2004-04-01

20

The role of small intestinal bacterial overgrowth in Parkinson's disease.  

PubMed

Parkinson's disease is associated with gastrointestinal motility abnormalities favoring the occurrence of local infections. The aim of this study was to investigate whether small intestinal bacterial overgrowth contributes to the pathophysiology of motor fluctuations. Thirty-three patients and 30 controls underwent glucose, lactulose, and urea breath tests to detect small intestinal bacterial overgrowth and Helicobacter pylori infection. Patients also underwent ultrasonography to evaluate gastric emptying. The clinical status and plasma concentration of levodopa were assessed after an acute drug challenge with a standard dose of levodopa, and motor complications were assessed by Unified Parkinson's Disease Rating Scale-IV and by 1-week diaries of motor conditions. Patients with small intestinal bacterial overgrowth were treated with rifaximin and were clinically and instrumentally reevaluated 1 and 6 months later. The prevalence of small intestinal bacterial overgrowth was significantly higher in patients than in controls (54.5% vs. 20.0%; P?=?.01), whereas the prevalence of Helicobacter pylori infection was not (33.3% vs. 26.7%). Compared with patients without any infection, the prevalence of unpredictable fluctuations was significantly higher in patients with both infections (8.3% vs. 87.5%; P?=?.008). Gastric half-emptying time was significantly longer in patients than in healthy controls but did not differ in patients based on their infective status. Compared with patients without isolated small intestinal bacterial overgrowth, patients with isolated small intestinal bacterial overgrowth had longer off time daily and more episodes of delayed-on and no-on. The eradication of small intestinal bacterial overgrowth resulted in improvement in motor fluctuations without affecting the pharmacokinetics of levodopa. The relapse rate of small intestinal bacterial overgrowth at 6 months was 43%. © 2013 Movement Disorder Society. PMID:23712625

Fasano, Alfonso; Bove, Francesco; Gabrielli, Maurizio; Petracca, Martina; Zocco, Maria Assunta; Ragazzoni, Enzo; Barbaro, Federico; Piano, Carla; Fortuna, Serena; Tortora, Annalisa; Di Giacopo, Raffaella; Campanale, Mariachiara; Gigante, Giovanni; Lauritano, Ernesto Cristiano; Navarra, Pierluigi; Marconi, Stefano; Gasbarrini, Antonio; Bentivoglio, Anna Rita

2013-08-01

21

The probiotic Escherichia coli strain Nissle 1917 interferes with invasion of human intestinal epithelial cells by different enteroinvasive bacterial pathogens.  

PubMed

The probiotic Escherichia coli strain Nissle 1917 (Mutaflor) of serotype O6:K5:H1 was reported to protect gnotobiotic piglets from infection with Salmonella enterica serovar Typhimurium. An important virulence property of Salmonella is invasion of host epithelial cells. Therefore, we tested for interference of E. coli strain Nissle 1917 with Salmonella invasion of INT407 cells. Simultaneous administration of E. coli strain Nissle 1917 and Salmonella resulted in up to 70% reduction of Salmonella invasion efficiency. Furthermore, invasion of Yersinia enterocolitica, Shigella flexneri, Legionella pneumophila and even of Listeria monocytogenes were inhibited by the probiotic E. coli strain Nissle 1917 without affecting the viability of the invasive bacteria. The observed inhibition of invasion was not due to the production of microcins by the Nissle 1917 strain because its isogenic microcin-negative mutant SK22D was as effective as the parent strain. Reduced invasion rates were also achieved if strain Nissle 1917 was separated from the invasive bacteria as well as from the INT407 monolayer by a membrane non-permeable for bacteria. We conclude E. coli Nissle 1917 to interfere with bacterial invasion of INT407 cells via a secreted component and not relying on direct physical contact with either the invasive bacteria or the epithelial cells. PMID:15039098

Altenhoefer, Artur; Oswald, Sibylle; Sonnenborn, Ulrich; Enders, Corinne; Schulze, Juergen; Hacker, Joerg; Oelschlaeger, Tobias A

2004-04-01

22

Intestinal alkaline phosphatase promotes gut bacterial growth by reducing the concentration of luminal nucleotide triphosphates.  

PubMed

The intestinal microbiota plays a pivotal role in maintaining human health and well-being. Previously, we have shown that mice deficient in the brush-border enzyme intestinal alkaline phosphatase (IAP) suffer from dysbiosis and that oral IAP supplementation normalizes the gut flora. Here we aimed to decipher the molecular mechanism by which IAP promotes bacterial growth. We used an isolated mouse intestinal loop model to directly examine the effect of exogenous IAP on the growth of specific intestinal bacterial species. We studied the effects of various IAP targets on the growth of stool aerobic and anaerobic bacteria as well as on a few specific gut organisms. We determined the effects of ATP and other nucleotides on bacterial growth. Furthermore, we examined the effects of IAP on reversing the inhibitory effects of nucleotides on bacterial growth. We have confirmed that local IAP bioactivity creates a luminal environment that promotes the growth of a wide range of commensal organisms. IAP promotes the growth of stool aerobic and anaerobic bacteria and appears to exert its growth promoting effects by inactivating (dephosphorylating) luminal ATP and other luminal nucleotide triphosphates. We observed that compared with wild-type mice, IAP-knockout mice have more ATP in their luminal contents, and exogenous IAP can reverse the ATP-mediated inhibition of bacterial growth in the isolated intestinal loop. In conclusion, IAP appears to promote the growth of intestinal commensal bacteria by inhibiting the concentration of luminal nucleotide triphosphates. PMID:24722905

Malo, Madhu S; Moaven, Omeed; Muhammad, Nur; Biswas, Brishti; Alam, Sayeda N; Economopoulos, Konstantinos P; Gul, Sarah Shireen; Hamarneh, Sulaiman R; Malo, Nondita S; Teshager, Abeba; Mohamed, Mussa M Rafat; Tao, Qingsong; Narisawa, Sonoko; Millán, José Luis; Hohmann, Elizabeth L; Warren, H Shaw; Robson, Simon C; Hodin, Richard A

2014-05-15

23

Enteric infection meets intestinal function: how bacterial pathogens cause diarrhoea  

Microsoft Academic Search

Infectious diarrhoea is a significant contributor to morbidity and mortality worldwide. In bacterium-induced diarrhoea, rapid loss of fluids and electrolytes results from inhibition of the normal absorptive function of the intestine as well as the activation of secretory processes. Advances in the past 10 years in the fields of gastrointestinal physiology, innate immunity and enteric bacterial virulence mechanisms highlight the

V. K. Viswanathan; Kim Hodges; Gail Hecht

2008-01-01

24

Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome  

Microsoft Academic Search

OBJECTIVE:Small intestinal bacterial overgrowth syndrome (SIBOS) is characterized by an abnormally high bacterial population level in the upper gut, exceeding 105 organisms\\/ml (5 log colony-forming unit (CFU)\\/ml). To understand its origin and select an appropriate antibiotic treatment, we have analyzed the bacterial populations contaminating the upper gut in SIBOS patients.METHODS:Jejunal samples of 63 consecutive patients with diarrhea or malabsorption and

Yoram Bouhnik; Sophie Alain; Alain Attar; Bernard Flourié; Laurent Raskine; Marie José Sanson-Le Pors; Jean-Claude Rambaud

1999-01-01

25

Intestinal gas dynamics and tolerance in humans  

Microsoft Academic Search

Background & Aims: Abdominal symptoms are often attributed to intestinal gas. In humans, gas production and composition have been previously investigated, but intestinal gas dynamics and tolerance remain virtually unknown. The aim of this study was to establish the relationship between intestinal gas loads, evacuation, perception of symptoms, and objective abdominal distention in healthy humans. Methods: A dose-response study was

Jordi Serra; Fernando Azpiroz

1998-01-01

26

Fucose Sensing Regulates Bacterial Intestinal Colonization  

PubMed Central

The mammalian gastrointestinal (GI) tract provides a complex and competitive environment for the microbiota1. Successful colonization by pathogens depends on scavenging nutrients, sensing chemical signals, competing with the resident bacteria, and precisely regulating expression of virulence genes2. The GI pathogen enterohemorrhagic E.coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression3–4. Here we show that these systems control the expression of a novel two-component signal transduction system, named FusKR, where FusK is the histidine sensor kinase (HK), and FusR the response regulator (RR). FusK senses fucose and controls expression of virulence and metabolic genes. This fucose-sensing system is required for robust EHEC colonization of the mammalian intestine. Fucose is highly abundant in the intestine5. Bacteroides thetaiotaomicron (B.theta) produces multiple fucosidases that cleave fucose from host glycans, resulting in high fucose availability in the gut lumen6. During growth in mucin, B.theta contributes to EHEC virulence by cleaving fucose from mucin, thereby activating the FusKR signaling cascade, modulating EHEC’s virulence gene expression. Our findings suggest that EHEC uses fucose, a host-derived signal made available by the microbiota, to modulate EHEC pathogenicity and metabolism.

Pacheco, Alline R.; Curtis, Meredith M.; Ritchie, Jennifer M.; Munera, Diana; Waldor, Matthew K.; Moreira, Cristiano G.; Sperandio, Vanessa

2012-01-01

27

Human intestinal spirochetosis - a review  

PubMed Central

Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS.

Tsinganou, Efstathia; Gebbers, Jan-Olaf

2010-01-01

28

Small Intestinal Bacterial Overgrowth Recurrence After Antibiotic Therapy  

Microsoft Academic Search

OBJECTIVES:Current treatment for small intestinal bacterial overgrowth (SIBO) is based on courses of broad-spectrum antibiotics. No data concerning SIBO recurrence are available. The aims of the present study were to investigate SIBO recurrence as assessed by glucose breath test (GBT) after antibiotic treatment and conditions associated to SIBO recurrence.METHODS:Eighty consecutive patients affected by SIBO and decontaminated by rifaximin (1,200 mg

Ernesto C. Lauritano; Maurizio Gabrielli; Emidio Scarpellini; Andrea Lupascu; Marialuisa Novi; Sandra Sottili; Giovanna Vitale; Valentina Cesario; Michele Serricchio; Giovanni Cammarota; Giovanni Gasbarrini; Antonio Gasbarrini

2008-01-01

29

Bacterial Populations of the Small Intestine in Uremia  

Microsoft Academic Search

The small intestinal bacterial flora of 15 patients with chronic renal insufficiency was compared with that of subjects with blind loop syndrome. 9 patients were on regular hemodialysis with high protein intake and 6 (serum creatinine 7.5 to 12.5 mg\\/dl) were maintained on low protein diet. The chronic renal patients harbored a greatly increased microbial flora of both anaerobes and

Michael L. Simenhoff; Jussi J. Saukkonen; James F. Burke; Russell W. Schaedler; Susan J. Gordon

1978-01-01

30

Link between hypothyroidism and small intestinal bacterial overgrowth  

PubMed Central

Altered gastrointestinal (GI) motility is seen in many pathological conditions. Reduced motility is one of the risk factors for development of a small intestinal bacterial overgrowth (SIBO). Hypothyroidism is associated with altered GI motility. The aim of this article was to study the link between hypothyroidism, altered GI motility and development of SIBO. Published literature was reviewed to study the association of altered GI motility, SIBO and hypothyroidism. Altered GI motility leads to SIBO. SIBO is common in patients with hypothyroidism. Patients with chronic GI symptoms in hypothyroidism should be evaluated for the possibility of SIBO. Both antibiotics and probiotics have been studied and found to be effective in management of SIBO.

Patil, Anant D.

2014-01-01

31

Patients with Chronic Renal Failure Have Abnormal Small Intestinal Motility and a High Prevalence of Small Intestinal Bacterial Overgrowth  

Microsoft Academic Search

Background\\/Aims: Gastrointestinal (GI) symptoms are common among patients with chronic renal failure (CRF). The pathogenesis of these symptoms is probably multifactorial. Our aims were to assess gastric and small intestinal motility and the prevalence of small intestinal bacterial overgrowth (SIBO) in order to clarify possible pathophysiological mechanisms behind these symptoms in CRF patients. Methods: Twenty-two patients with CRF, 12 with

Hans Strid; Magnus Simrén; Per-Ove Stotzer; Gisela Ringström; Hasse Abrahamsson; Einar S. Björnsson

2003-01-01

32

Small intestinal bacterial overgrowth and warfarin dose requirement variability.  

PubMed

The dose of warfarin needed to obtain a therapeutic anticoagulation level varies widely among patients and can undergo abrupt changes for unknown reasons. Drug interactions and genetic factors may partially explain these differences. Intestinal flora produces vitamin K2 (VK2) and patients with small intestinal bacterial overgrowth (SIBO) rarely present reduced INR values due to insufficient dietary vitamin K. The present study was undertaken to investigate whether SIBO occurrence may affect warfarin dose requirements in anticoagulated patients. Based on their mean weekly dose of warfarin while on stable anticoagulation, 3 groups of 10 patients each were defined: low dose (LD, or=70 mg/wk). Each patient underwent a lactulose breath test to diagnose SIBO. Plasma levels of warfarin and vitamin K-analogues were also assessed. Patients with an altered breath test were 50% in the VHD group, 10% in the HD group, and none in the LD group (P=0.01). Predisposing factors to SIBO were more frequent in the VHD group, while warfarin interfering variables were not. VHD patients were younger and had a higher plasma vitamin K1 (VK1) concentration (P>0.05). On the contrary, the plasma VK2 levels tended to be lower. This pilot study suggests that SIBO may increase a patient's warfarin dose requirement by increasing dietary VK1 absorption through the potentially damaged intestinal mucosa rather than increasing intestinal VK2 biosynthesis. Larger studies are needed to confirm these preliminary data and to evaluate the effects of SIBO decontamination on warfarin dosage. PMID:20051286

Giuliano, Vittorio; Bassotti, Gabrio; Mourvaki, Evangelia; Castellani, Danilo; Filippucci, Esmeralda; Sabatino, Giuseppe; Gizzi, Stefania; Palmerini, Francesco; Galli, Francesco; Morelli, Olivia; Baldoni, Monia; Morelli, Antonio; Iorio, Alfonso

2010-07-01

33

Bacterial Overgrowth in the Cystic Fibrosis Transmembrane Conductance Regulator Null Mouse Small Intestine  

Microsoft Academic Search

We recently reported the inflammation of the cystic fibrosis (CF) mouse small intestine, and we hypothesized bacterial overgrowth as a possible cause. Quantitative PCR of bacterial 16S genomic DNA in the CF mouse small intestine revealed an increase of greater than 40-fold compared to controls. Sequencing of 16S PCR products and Gram staining showed that the majority of bacteria in

Oxana Norkina; Tim G. Burnett; Robert C. De Lisle

2004-01-01

34

Intestinal bacterial diversity in live rock lobster Panulirus homarus (Linnaeus) (Decapoda, Pleocyemata, Palinuridae) during transportation process  

Microsoft Academic Search

This study investigates the bacterial diversity in the intestine of rock lobster Panulirus homarus during live transportation process lasting for 14h. The total viable count (TVC) in the intestine of P. homarus (Linnaeus, 1758) prior to packing (control) was 130.33 x 106 cfu ml-1. In the intestine of packed lobsters (experimental), the TVC showed an increasing trend and the recorded

GRASIAN IMMANUEL; PALANISAMY IYAPPA RAJ; PALANICHAMY ESAKKI RAJ; ARUNACHALAM PALAVESAM

35

Confirmation and Prevention of Intestinal Barrier Dysfunction and Bacterial Translocation Caused by Methotrexate  

Microsoft Academic Search

When intestinal barrier function is damaged bacterial translocation (BT) can occur. The injury to intestinal barrier function caused by chemotherapy has been investigated in some studies, however, definitive evidence of BT caused by chemotherapy is lacking. The aim of this study was to investigate small intestinal barrier dysfunction and BT and to evaluate the preventive effect of granulocyte colony-stimulating factor

Desheng Song; Bin Shi; Hua Xue; Yousheng Li; Xiaodong Yang; Baojun Yu; Zhe Xu; Fukun Liu; Jieshou Li

2006-01-01

36

Cholecystokinin Increases Small Intestinal Motility and Reduces Enteric Bacterial Overgrowth and Translocation in Rats with Surgically Induced Acute Liver Failure  

Microsoft Academic Search

Enteric bacterial translocation into extraintestinal sites has been proposed as a potential route for bacterial infection in acute liver failure. Bacterial overgrowth in the intestine plays an important role in the etiology of bacterial translocation from the gut. The aim of the present study was to evaluate the influence of exogenous cholecystokinin (CCK) on intestinal transit time, enteric bacterial overgrowth

Xiangdong Wang; Vasile Soltesz; Jan Axelson; Roland Andersson

1996-01-01

37

The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor ? in the pathogenesis of non-alcoholic steatohepatitis  

Microsoft Academic Search

BACKGROUNDSmall intestinal bacterial overgrowth may contribute to the development of non-alcoholic steatohepatitis, perhaps by increasing intestinal permeability and promoting the absorption of endotoxin or other enteric bacterial products.AIMSTo investigate the prevalence of small intestinal bacterial overgrowth, increased intestinal permeability, elevated endotoxin, and tumour necrosis factor ? (TNF-?) levels in patients with non-alcoholic steatohepatitis and in control subjects.PATIENTS AND METHODSTwenty two

A J Wigg; I C Roberts-Thomson; R B Dymock; P J McCarthy; R H Grose; A G Cummins

2001-01-01

38

The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor Æ in the pathogenesis of non-alcoholic steatohepatitis  

Microsoft Academic Search

Background—Small intestinal bacterial overgrowth may contribute to the devel- opment of non-alcoholic steatohepatitis, perhaps by increasing intestinal perme- ability and promoting the absorption of endotoxin or other enteric bacterial prod- ucts. Aims—To investigate the prevalence of small intestinal bacterial overgrowth, in- creased intestinal permeability, elevated endotoxin, and tumour necrosis factor Æ (TNF-Æ) levels in patients with non- alcoholic steatohepatitis and

A J Wigg; I C Roberts-Thomson; R B Dymock; P J McCarthy; R H Grose; A G Cummins

39

Link between hypothyroidism and small intestinal bacterial overgrowth.  

PubMed

Altered gastrointestinal (GI) motility is seen in many pathological conditions. Reduced motility is one of the risk factors for development of a small intestinal bacterial overgrowth (SIBO). Hypothyroidism is associated with altered GI motility. The aim of this article was to study the link between hypothyroidism, altered GI motility and development of SIBO. Published literature was reviewed to study the association of altered GI motility, SIBO and hypothyroidism. Altered GI motility leads to SIBO. SIBO is common in patients with hypothyroidism. Patients with chronic GI symptoms in hypothyroidism should be evaluated for the possibility of SIBO. Both antibiotics and probiotics have been studied and found to be effective in management of SIBO. PMID:24944923

Patil, Anant D

2014-05-01

40

Regulation of Bacterial Pathogenesis by Intestinal Short-Chain Fatty Acids  

PubMed Central

The human gut microbiota is inextricably linked to health and disease. One important function of the commensal organisms living in the intestine is to provide colonization resistance against invading enteric pathogens. Because of the complex nature of the interaction between the microbiota and its host, multiple mechanisms likely contribute to resistance. In this review, we dissect the biological role of short-chain fatty acids (SCFA), which are fermentation end products of the intestinal microbiota, in host–pathogen interactions. SCFA exert an extensive influence on host physiology through nutritional, regulatory, and immunomodulatory functions and can also affect bacterial fitness as a form of acid stress. Moreover, SCFA act as a signal for virulence gene regulation in common enteric pathogens. Taken together, these studies highlight the importance of the chemical environment where the biology of the host, the microbiota, and the pathogen intersects, which provides a basis for designing effective infection prevention and control.

Sun, Yvonne; O'Riordan, Mary X. D.

2013-01-01

41

Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans  

PubMed Central

Background A powerful approach to understanding complex processes such as aging is to use model organisms amenable to genetic manipulation, and to seek relevant phenotypes to measure. Caenorhabditis elegans is particularly suited to studies of aging, since numerous single-gene mutations have been identified that affect its lifespan; it possesses an innate immune system employing evolutionarily conserved signaling pathways affecting longevity. As worms age, bacteria accumulate in the intestinal tract. However, quantitative relationships between worm genotype, lifespan, and intestinal lumen bacterial load have not been examined. We hypothesized that gut immunity is less efficient in older animals, leading to enhanced bacterial accumulation, reducing longevity. To address this question, we evaluated the ability of worms to control bacterial accumulation as a functional marker of intestinal immunity. Results We show that as adult worms age, several C. elegans genotypes show diminished capacity to control intestinal bacterial accumulation. We provide evidence that intestinal bacterial load, regulated by gut immunity, is an important causative factor of lifespan determination; the effects are specified by bacterial strain, worm genotype, and biologic age, all acting in concert. Conclusions In total, these studies focus attention on the worm intestine as a locus that influences longevity in the presence of an accumulating bacterial population. Further studies defining the interplay between bacterial species and host immunity in C. elegans may provide insights into the general mechanisms of aging and age-related diseases.

2012-01-01

42

Comparison of intestinal bacterial communities in grass carp, Ctenopharyngodon idellus, from two different habitats  

NASA Astrophysics Data System (ADS)

The intestinal bacteria of vertebrates form a close relationship with their host. External and internal conditions of the host, including its habitat, affect the intestinal bacterial community. Similarly, the intestinal bacterial community can, in turn, influence the host, particularly with respect to disease resistance. We compared the intestinal bacterial communities of grass carp that were collected from farm-ponds or a lake. We conducted denaturing gradient gel electrophoresis of amplified 16S rRNA genes, from which 66 different operational taxonomic units were identified. Using both the unweighted pair-group method with arithmetic means clustering and principal component analysis ordination, we found that the intestinal bacterial communities from the two groups of pond fish were clustered together and inset into the clusters of wild fish, except for DF-7, and there was no significant correlation between genetic diversity of grass carp and their intestinal bacterial communities (Mantel one-tailed test, R=0.157, P=0.175). Cetobacterium appeared more frequently in the intestine of grass carp collected from pond. A more thorough understanding of the role played by intestinal microbiota on fish health would be of considerable benefit to the aquaculture industry.

Ni, Jiajia; Yu, Yuhe; Zhang, Tanglin; Gao, Lei

2012-09-01

43

Small intestinal motility disturbances and bacterial overgrowth in patients with liver cirrhosis and portal hypertension  

Microsoft Academic Search

ObjectivesAltered small bowel motility and a high prevalence of small intestinal bacterial overgrowth (SIBO) has been observed in patients with liver cirrhosis. Our aim was to explore the relationship between motility abnormalities, portal hypertension, and SIBO.

Steingerdur Anna Gunnarsdottir; Riadh Sadik; Steven Shev; Magnus Simrén; Henrik Sjövall; Per-Ove Stotzer; Hasse Abrahamsson; Rolf Olsson; Einar S Björnsson

2003-01-01

44

Bacterial community associated with the intestinal tract of P. monodon in commercial farms.  

PubMed

The potentially important roles of intestinal bacteria on immune response, disease resistance, and nutrition for the black tiger shrimp Penaeus monodon have been increasingly investigated. However, so far, little is known about the intestinal bacterial community of the shrimp in the commercial aquaculture settings. In this study, the intestinal bacterial communities of juvenile P. monodon (70 individuals) from eight commercial farms in Thailand were examined using 16S rDNA PCR-DGGE, and seven 16S rDNA clone libraries from representative DGGE profiles were constructed. Bacteria in the ?-Proteobacteria class were the only common bacteria group found in the intestinal tracts of shrimp from all farms. The dominant bacterial genera in the intestinal population of each shrimp varied among different farms, and these genera were Vibrio, Photobacterium, Aeromonas, or Propionigenium (phylum Fusobacteria). Other commonly found genera included Actinomyces, Anaerobaculum, Halospirulina, Pseudomonas, Mycoplasma, and Shewanella. Twelve phyla of bacteria including Proteobacteria, Firmicutes, Fusobacteria, Actinobacteria, Cyanobacteria, Tenericutes, Deinococcus-Thermus, Planctomycetes, Spirochaetes, Synergistetes, Thermotogae, and Verrucomicrobia were represented in the sequences. Additionally, strictly anaerobic bacteria such as Propionigenium and Fusibacter were found. These intestinal bacterial communities varied significantly among different commercial farms and were distinct from their rearing water. The results provide descriptive structures of the intestinal bacterial communities of P. monodon in commercial farms, which can further be applied to areas of research on the immunity, disease resistance, and nutrition of shrimp to improve aquaculture of the black tiger shrimp. PMID:21915632

Chaiyapechara, Sage; Rungrassamee, Wanilada; Suriyachay, Ittipon; Kuncharin, Yanin; Klanchui, Amornpan; Karoonuthaisiri, Nitsara; Jiravanichpaisal, Pikul

2012-05-01

45

Microarray method to monitor 40 intestinal bacterial species in the study of azo dye reduction  

Microsoft Academic Search

Azo dyes are widely used in dye manufacturing, paper printing, textile industries, and as tattoo pigmentation. Since intestinal and skin bacteria can metabolize certain azo dyes to carcinogenic compounds, many researchers have studied the azoreductases of these bacteria. In this study, we used a microarray method to identify the intestinal bacterial species from cultured fecal samples in Brain Heart Infusion

Rong-Fu Wang; Huizhong Chen; Donald D. Paine; Carl E. Cerniglia

2004-01-01

46

The human commensal Bacteroides fragilis binds intestinal mucin.  

PubMed

The mammalian gastrointestinal tract harbors a vast microbial ecosystem, known as the microbiota, which benefits host biology. Bacteroides fragilis is an important anaerobic gut commensal of humans that prevents and cures intestinal inflammation. We wished to elucidate aspects of gut colonization employed by B. fragilis. Fluorescence in situ hybridization was performed on colonic tissue sections from B. fragilis and Escherichia coli dual-colonized gnotobiotic mice. Epifluorescence imaging reveals that both E. coli and B. fragilis are found in the lumen of the colon, but only B. fragilis is found in the mucosal layer. This observation suggests that physical association with intestinal mucus could be a possible mechanism of gut colonization by B. fragilis. We investigated this potential interaction using an in vitro mucus binding assay and show here that B. fragilis binds to murine colonic mucus. We further demonstrate that B. fragilis specifically and quantitatively binds to highly purified mucins (the major constituent in intestinal mucus) using flow cytometry analysis of fluorescently labeled purified murine and porcine mucins. These results suggest that interactions between B. fragilis and intestinal mucin may play a critical role during host-bacterial symbiosis. PMID:21664470

Huang, Julie Y; Lee, S Melanie; Mazmanian, Sarkis K

2011-08-01

47

Probiotics prevent bacterial translocation and improve intestinal barrier function in rats following chronic psychological stress  

PubMed Central

Background and aim Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology. Methods Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation. Results All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes. Conclusion These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.

Zareie, M; Johnson-Henry, K; Jury, J; Yang, P-C; Ngan, B-Y; McKay, D M; Soderholm, J D; Perdue, M H; Sherman, P M

2006-01-01

48

Bacterial Overgrowth in the Cystic Fibrosis Transmembrane Conductance Regulator Null Mouse Small Intestine  

PubMed Central

We recently reported the inflammation of the cystic fibrosis (CF) mouse small intestine, and we hypothesized bacterial overgrowth as a possible cause. Quantitative PCR of bacterial 16S genomic DNA in the CF mouse small intestine revealed an increase of greater than 40-fold compared to controls. Sequencing of 16S PCR products and Gram staining showed that the majority of bacteria in the CF mouse intestine were gram negative. Bacteria were observed to colonize the mucus that accumulates in the intestinal lumen of mice with CF. Impaired Paneth cell defenses were suggested by observation of partially dispersed Paneth granules in the mucus plugs of CF mouse intestinal crypts, and this mucus was strongly immunoreactive for Paneth cell bactericidal products. The role of bacterial overgrowth in intestinal inflammation in CF was tested by treating mice with oral antibiotics (ciprofloxacin and metronidazole) for 3 weeks, which reduced bacterial load in the CF mouse small intestine over 400-fold. Antibiotic treatment decreased the expression of the inflammation-related genes mast cell protease 2, leucine-rich ?2 glycoprotein/leucine-rich high endothelial venule glycoprotein, suppressor of cytokine signaling 3, hematopoietic cell transcript 1, and resistin-like molecule ?/found in inflammatory zone 2, all of which were no longer expressed at levels significantly different from control levels. The reduction of intestinal bacteria also significantly improved the growth of CF mice but had no effect on the growth of wild-type mice. These data suggest that bacterial overgrowth in the CF mouse small intestine has a role in inflammation and contributes to the failure to thrive in this mouse model of CF.

Norkina, Oxana; Burnett, Tim G.; De Lisle, Robert C.

2004-01-01

49

Tipping elements in the human intestinal ecosystem.  

PubMed

The microbial communities living in the human intestine can have profound impact on our well-being and health. However, we have limited understanding of the mechanisms that control this complex ecosystem. Here, based on a deep phylogenetic analysis of the intestinal microbiota in a thousand western adults, we identify groups of bacteria that exhibit robust bistable abundance distributions. These bacteria are either abundant or nearly absent in most individuals, and exhibit decreased temporal stability at the intermediate abundance range. The abundances of these bimodally distributed bacteria vary independently, and their abundance distributions are not affected by short-term dietary interventions. However, their contrasting alternative states are associated with host factors such as ageing and overweight. We propose that the bistable groups reflect tipping elements of the intestinal microbiota, whose critical transitions may have profound health implications and diagnostic potential. PMID:25003530

Lahti, Leo; Salojärvi, Jarkko; Salonen, Anne; Scheffer, Marten; de Vos, Willem M

2014-01-01

50

Tipping elements in the human intestinal ecosystem  

PubMed Central

The microbial communities living in the human intestine can have profound impact on our well-being and health. However, we have limited understanding of the mechanisms that control this complex ecosystem. Here, based on a deep phylogenetic analysis of the intestinal microbiota in a thousand western adults, we identify groups of bacteria that exhibit robust bistable abundance distributions. These bacteria are either abundant or nearly absent in most individuals, and exhibit decreased temporal stability at the intermediate abundance range. The abundances of these bimodally distributed bacteria vary independently, and their abundance distributions are not affected by short-term dietary interventions. However, their contrasting alternative states are associated with host factors such as ageing and overweight. We propose that the bistable groups reflect tipping elements of the intestinal microbiota, whose critical transitions may have profound health implications and diagnostic potential.

Lahti, Leo; Salojarvi, Jarkko; Salonen, Anne; Scheffer, Marten; de Vos, Willem M.

2014-01-01

51

Jejunal bacterial overgrowth and intestinal permeability in children with immunodeficiency syndromes  

Microsoft Academic Search

Seventeen paediatric patients with immunodeficiency syndromes (10 with selective IgA deficiency, four with panhypogammaglobulinaemia, and three with selective T cell deficiency) were investigated for bacterial overgrowth of the small intestine and gut permeability to macromolecules. Five of 12 patients showed viable bacterial counts of more than 2 x 10(5)\\/ml in jejunal fluid. Bacterial overgrowth was also confirmed indirectly by breath

C Pignata; G Budillon; G Monaco; E Nani; R Cuomo; G Parrilli; F Ciccimarra

1990-01-01

52

Cd1d-dependent regulation of bacterial colonization in the intestine of mice  

PubMed Central

The accumulation of certain species of bacteria in the intestine is involved in both tissue homeostasis and immune-mediated pathologies. The host mechanisms involved in controlling intestinal colonization with commensal bacteria are poorly understood. We observed that under specific pathogen–free or germ-free conditions, intragastric administration of Pseudomonas aeruginosa, E. coli, Staphylococcus aureus, or Lactobacillus gasseri resulted in increased colonization of the small intestine and bacterial translocation in mice lacking Cd1d, an MHC class I–like molecule, compared with WT mice. In contrast, activation of Cd1d-restricted T cells (NKT cells) with ?-galactosylceramide caused diminished intestinal colonization with the same bacterial strains. We also found prominent differences in the composition of intestinal microbiota, including increased adherent bacteria, in Cd1d–/– mice in comparison to WT mice under specific pathogen–free conditions. Germ-free Cd1d–/– mice exhibited a defect in Paneth cell granule ultrastructure and ability to degranulate after bacterial colonization. In vitro, NKT cells were shown to induce the release of lysozyme from intestinal crypts. Together, these data support a role for Cd1d in regulating intestinal colonization through mechanisms that include the control of Paneth cell function.

Nieuwenhuis, Edward E.S.; Matsumoto, Tetsuya; Lindenbergh, Dicky; Willemsen, Rob; Kaser, Arthur; Simons-Oosterhuis, Ytje; Brugman, Sylvia; Yamaguchi, Keizo; Ishikawa, Hiroki; Aiba, Yuji; Koga, Yasuhiro; Samsom, Janneke N.; Oshima, Kenshiro; Kikuchi, Mami; Escher, Johanna C.; Hattori, Masahira; Onderdonk, Andrew B.; Blumberg, Richard S.

2009-01-01

53

Cholesterol esterase activity of human intestinal mucosa  

SciTech Connect

It has been suggested that cholesterol absorption in humans is dependent on bile acid pool composition and that expansion of the cholic acid pool size is followed by an increase of the absorption values. Similar observations were reported in rats. In the present study, therefore, the authors investigated some general properties of human intestinal cholesterol esterase, with particular emphasis on the effect of bile acids on this enzymatic activity. Twenty-nine segments of small intestine were taken during operations; the enzymatic activity was studied by using mucosal homogenate as a source of enzyme and oleic acid, cholesterol, and UC-labeled cholesterol as substrates. The time-activity relationship was linear within the first two hours; optimal pH for esterification ranged between 5 and 6.2. There was little difference between the esterifying activity of the jejunal and ileal mucosa. Esterification of cholesterol was observed with all the investigated fatty acids but was maximal with oleic acid. Bile acids did not affect cholesterol esterase activity when present in the incubation mixture at 0.1 and 1.0 mM; the enzymatic activity, however, was significantly inhibited when bile acids were added at 20 mM. In conclusion, this study has shown that the human intestinal mucosa possesses a cholesterol esterase activity; at variance with the rat, however, the human enzyme does not seem to be stimulated by trihydroxy bile acids.

Ponz de Leon, M.; Carubbi, F.; Di Donato, P.; Carulli, N.

1985-11-01

54

Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome  

Microsoft Academic Search

OBJECTIVES:Irritable bowel syndrome is the most common gastrointestinal diagnosis. The symptoms of irritable bowel syndrome are similar to those of small intestinal bacterial overgrowth. The purpose of this study was to test whether overgrowth is associated with irritable bowel syndrome and whether treatment of overgrowth reduces their intestinal complaints.METHODS:Two hundred two subjects in a prospective database of subjects referred from

Mark Pimentel; Evelyn J Chow; Henry C Lin

2000-01-01

55

Neutrophil depletion attenuates human intestinal reperfusion injury.  

PubMed

Intestinal ischemia/reperfusion injury (I/R) results from reactive oxygen metabolites generated by the xanthine oxidase system and activated neutrophils (PMN). In animal models, removing PMN from initial reperfusate has consistently decreased tissue injury. This experiment was designed to test this potential clinical treatment in human bowel subjected to I/R. The extent of reperfusion injury was assessed by measuring the activity of mucosal alkaline phosphatase (A phi), which is a specific marker of reperfusion injury. Human small intestine (n = 13) obtained at the time of organ harvest for transplantation was perfused for 60 min on an ex vivo perfusion circuit. Reperfusate consisted of autologous blood passed through a leukocyte filter (n = 6) or unfiltered blood (n = 7). Control intestine was sampled at harvest, after transport to the lab on ice (cold ischemia), and after 60 min warm ischemia. Mucosa was homogenized and assayed for A phi activity by cleavage of p-nitrophenyl phosphate. A phi activity (nmole/mg/min) was not decreased after either cold (774 +/- 37) or warm (753 +/- 40) ischemia compared to freshly harvested bowel (770 +/- 51). Both reperfused segments showed a significant decrease in A phi activity compared to controls (P < 0.05); however, reperfusion with leukocyte-filtered blood attenuated the decrease in enzyme activity compared to unfiltered blood (327 +/- 30 vs 506 +/- 25, P < 0.05), constituting an apparent reduction in injury of 35%. The observation that the severity of reperfusion injury was decreased by removal of PMN from the reperfusate demonstrates the efficacy of this strategy in human intestine for the first time. PMID:8041137

Sisley, A C; Desai, T; Harig, J M; Gewertz, B L

1994-07-01

56

Small intestinal bacterial overgrowth in patients with progressive familial intrahepatic cholestasis.  

PubMed

Background & Aims: To date, no studies concerning the presence of small intestinal bacterial overgrowth in patients with progressive familial intrahepatic cholestasis were published. Based upon characteristic of progressive familial intrahepatic cholestasis one can expect the coexistence of small intestinal bacterial overgrowth. The aim of the study was to assess the incidence of small intestinal bacterial overgrowth in patients with progressive familial intrahepatic cholestasis. Methods: 26 patients aged 8 to 25 years with progressive familial intrahepatic cholestasis were included in the study. Molecular analysis of ABCB11 gene was performed in the vast majority of patients. In all patients Z-score for body weight and height, biochemical tests (bilirubin, bile acid concentration, fecal fat excretion) were assessed. In all patients hydrogen-methane breath test was performed. Results: On the basis of first hydrogen-methane breath test, diagnosis of small intestinal bacterial overgrowth was confirmed in 9 patients (35%), 5 patients (19%) had borderline results. The second breath test was performed in 10 patients: in 3 patients results were still positive and 2 patients had a borderline result. The third breath test was conducted in 2 patients and positive results were still observed. Statistical analysis did not reveal any significant correlations between clinical, biochemical and therapeutic parameters in patients with progressive familial intrahepatic cholestasis and coexistence of small intestinal bacterial overgrowth. Conclusions: Our results suggest that small intestinal bacterial overgrowth is frequent in patients with progressive familial intrahepatic cholestasis. Moreover, it seems that this condition has the tendency to persist or recur, despite the treatment. PMID:24644547

Lisowska, Aleksandra; Kobelska-Dubiel, Natalia; Jankowska, Irena; Paw?owska, Joanna; Moczko, Jerzy; Walkowiak, Jaros?aw

2014-01-01

57

The effect of glucagon-like peptide 2 on intestinal permeability and bacterial translocation in acute necrotizing pancreatitis  

Microsoft Academic Search

Background: Acute pancreatitis (AP) initiates a generalized inflammatory response that increases intestinal permeability and promotes bacterial translocation (BT). Impairment of the intestinal epithelial barrier is known to promote BT. Glucagon-like peptide 2 (GLP-2), a 33 residue peptide hormone, is a key regulator of the intestinal mucosa by stimulating epithelial growth. The purpose of this study was to determine whether GLP-2

George J Kouris; Qiang Liu; H Rossi; Goldie Djuricin; Paulo Gattuso; C Nathan; Robert A Weinstein; Richard A Prinz

2001-01-01

58

Bacterial diversity in the intestinal tract of the fungus- cultivating termite Macrotermes michaelseni (Sjöstedt)  

Microsoft Academic Search

Microorganisms in the intestinal tracts of termites play a crucial role in the nutritional physiology of termites. The bacterial diversity in the fungus-cultivating Macrotermes michaelseni was examined using both molecular and culture dependent methods. Total DNA was extracted from the gut of the termite and 16S rRNA genes were amplified using bacterial specific primers. Representatives from forty-one (41) RFLP patterns

Lucy Mwende Mackenzie; Anne Thairu Muigai; Ellie Onyango Osir; Wilber Lwande; Martin Keller; Gerardo Toledo; Hamadi Iddi Boga

2007-01-01

59

Supplemental Dietary Arginine Accelerates Intestinal Mucosal Regeneration and Enhances Bacterial Clearance Following Radiation Enteritis in Rats  

Microsoft Academic Search

Background.Arginine is a dibasic amino acid with significant metabolic and immunologic, effects especially in trauma and stress situations. Arginine supplementation has been shown to promote wound healing and improve immune system. We designed a study to evaluate the effects of supplemental dietary arginine on intestinal mucosal recovery and bacterial translocation and bacterial clearance after induction of radiation injury in rats.Methods.Twenty-one

A. Tayfun Gurbuz; Joseph Kunzelman; Eric E. Ratzer

1998-01-01

60

Bacterial translocation and change in intestinal permeability in patients after abdominal surgery  

Microsoft Academic Search

Summary  The purpose of this study was to investigate bacterial translocation and change in intestinal permeability in patients after\\u000a abdominal surgery. Sixty-three patients undergoing elective abdominal surgery were enrolled in the study. Blood samples were\\u000a collected prior to operation and 2, 24, 48 h after surgery for bacterial culture, microbial DNA extraction, plasma D-lactate\\u000a and endotoxin measurement. PCR analysis was performed

Zhi Qiao; Zhanliang Li; Jiye Li; Lianrong Lu; Yi Lv; Junyou Li

2009-01-01

61

The intestinal bacterial community in the food waste-reducing larvae of Hermetia illucens.  

PubMed

As it is known that food waste can be reduced by the larvae of Hermetia illucens (Black soldier fly, BSF), the scientific and commercial value of BSF larvae has increased recently. We hypothesised that the ability of catabolic degradation by BSF larvae might be due to intestinal microorganisms. Herein, we analysed the bacterial communities in the gut of BSF larvae by pyrosequencing of extracting intestinal metagenomic DNA from larvae that had been fed three different diets. The 16S rRNA sequencing results produced 9737, 9723 and 5985 PCR products from larval samples fed food waste, cooked rice and calf forage, respectively. A BLAST search using the EzTaxon program showed that the bacterial community in the gut of larvae fed three different diets was mainly composed of the four phyla with dissimilar proportions. Although the composition of the bacterial communities depended on the different nutrient sources, the identified bacterial strains in the gut of BSF larvae represented unique bacterial species that were unlike the intestinal microflora of other insects. Thus, our study analysed the structure of the bacterial communities in the gut of BSF larvae after three different feedings and assessed the application of particular bacteria for the efficient degradation of organic compounds. PMID:21267722

Jeon, Hyunbum; Park, Soyoung; Choi, Jiyoung; Jeong, Gilsang; Lee, Sang-Beom; Choi, Youngcheol; Lee, Sung-Jae

2011-05-01

62

Intestinal drug solubility estimation based on simulated intestinal fluids: comparison with solubility in human intestinal fluids.  

PubMed

The purpose of this study was to validate both existing fasted and fed state simulated intestinal fluids (FaSSIF and FeSSIF), and simpler, alternative media for predicting intraluminal drug solubility during drug discovery and early drug development. For 17 model drugs, the solubilizing capacity of FaSSIF(c) and FeSSIF(c) (subscript indicates the use of crude taurocholate) and different concentrations of D-?-tocopheryl polyethylene glycol 1000 succinate (TPGS) in phosphate buffer were correlated with the solubilizing capacity of human intestinal fluids (HIF) in the fasted and the early postprandial state. A good correlation between solubility in fasted HIF and FaSSIF(c) and between solubility in fed HIF and FeSSIF(c) was obtained, indicated by R(2) values of 0.91 and 0.86, respectively. Comparable values were obtained for 0.1% TPGS for the fasted state (R(2)=0.84) and 2% TPGS for the fed state (R(2)=0.84). Direct estimation of intestinal drug solubility by the measured solubilities in FaSSIF(c) and FeSSIF(c) was acceptable. However, better estimates were obtained by calculating solubilities based on the equations describing the relationship between solubilities in FaSSIF(c) and FeSSIF(c) as function of observed solubilities in HIF. Using this approach, the predictive value of the TPGS-based solvent system was also acceptable and comparable to that of FaSSIF(c) and FeSSIF(c). In conclusion, FaSSIF(c) and FeSSIF(c) can be considered biorelevant media for intestinal solubility estimation. A simpler TPGS-based system may be a valuable alternative with improved stability and lower cost. PMID:21570465

Clarysse, Sarah; Brouwers, Joachim; Tack, Jan; Annaert, Pieter; Augustijns, Patrick

2011-07-17

63

Fermented liquid feed enhances bacterial diversity in piglet intestine.  

PubMed

Because of limitations imposed on the antibiotic use in animal industry, there is a need for alternatives to maintain the efficiency of production. One of them may be the use of fermented liquid feed (FLF) but how it affects gut ecology is poorly understood. We investigated the effect of three diets, standard dry feed (control), dry feed supplemented with antibiotics, and fermented liquid feed (FLF, fermented with Lactobacillus plantarum), on gut bacterial diversity in piglets. The structure of the ileal and caecal communities was estimated by sequencing the SSU rRNA gene libraries. Antibiotic-supplemented feed slightly increased bacterial diversity in the ileum but reduced it in the caecum while in FLF-fed animals bacterial diversity was elevated. The majority of bacterial sequences in the ileum of all three groups belonged to lactobacilli (92-98%). In the caecum the lactobacilli were still dominant in control and antibiotic-fed animals (59% and 64% of total bacterial sequences, respectively) but in FLF-fed animals they fell to 31% with the concomitant increase in the Firmicutes diversity represented by the Dorea, Coprococcus, Roseburia and Faecalibacterium genera. Thus FLF affects the gut ecology in a different way than antibiotics and contributes to the enhanced bacterial diversity in the gastrointestinal tract. PMID:19393756

Tajima, Kiyoshi; Ohmori, Hideyuki; Aminov, Rustam I; Kobashi, Yuri; Kawashima, Tomoyuki

2010-02-01

64

Human Intestinal Nematodiasis in the United States  

PubMed Central

Human intestinal nematodes, all of which can be acquired in the continental United States, can cause a variety of ills including iron deficiency anemia, surgical emergencies, eosinophilic pneumonia, malabsorption, dysentery, myositis, and death. The severity of illness is related to the number of parasites acquired exogenously or the ability of the parasite to multiply within the host. Diagnosis of clinically significant infection can usually be made by stool examination, and appropriate treatment requires an understanding of the life-span and pathogenic potential of the parasite.

Barrett-Connor, Elizabeth

1972-01-01

65

Effect of Pancreatin Preparation on Intestinal Bacterial Overgrowth in Mild to Moderate Chronic Pancreatitis  

Microsoft Academic Search

Introduction: In our previous bacterial overgrowth (BO) of the small intestine was sig- nificantly more common study in patients with mild to moderate pancreatic insuffi- ciency than in cases with severe chronic pancreatitis. Probably the pancreas enzyme substitution, used only in the cases of severe pancreas insufficiency, had an important role in the treatment of BO. Aims: The purpose of

Á. Pap; E. Schäfer; M. Burai; R. Schwab

66

The Human Vaginal Bacterial Biota and Bacterial Vaginosis  

PubMed Central

The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV). PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition.

Srinivasan, Sujatha; Fredricks, David N.

2008-01-01

67

The human vaginal bacterial biota and bacterial vaginosis.  

PubMed

The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV). PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition. PMID:19282975

Srinivasan, Sujatha; Fredricks, David N

2008-01-01

68

Human Intestinal Cells Modulate Conjugational Transfer of Multidrug Resistance Plasmids between Clinical Escherichia coli Isolates  

PubMed Central

Bacterial conjugation in the human gut microbiota is believed to play a major role in the dissemination of antibiotic resistance genes and virulence plasmids. However, the modulation of bacterial conjugation by the human host remains poorly understood and there is a need for controlled systems to study this process. We established an in vitro co-culture system to study the interaction between human intestinal cells and bacteria. We show that the conjugation efficiency of a plasmid encoding an extended spectrum beta-lactamase is reduced when clinical isolates of Escherichia coli are co-cultured with human intestinal cells. We show that filtered media from co-cultures contain a factor that reduces conjugation efficiency. Protease treatment of the filtered media eliminates this inhibition of conjugation. This data suggests that a peptide or protein based factor is secreted on the apical side of the intestinal cells exposed to bacteria leading to a two-fold reduction in conjugation efficiency. These results show that human gut epithelial cells can modulate bacterial conjugation and may have relevance to gene exchange in the gut.

Machado, Ana Manuel Dantas; Sommer, Morten O. A.

2014-01-01

69

THE HUMAN INTESTINAL CYTOCHROME P450 "PIE"  

PubMed Central

Cytochromes P450 (P450s) 3A, 2C, and 1A2 constitute the major “pieces” of the human liver P450 “pie” and account, on average, for 40, 25, and 18%, respectively, of total immunoquantified P450s (J Pharmacol Exp Ther 270:414–423, 1994). The P450 profile in the human small intestine has not been fully characterized. Therefore, microsomes prepared from mucosal scrapings from the duodenal/jejunal portion of 31 human donor small intestines were analyzed by Western blot using selective P450 antibodies. P450s 3A4, 2C9, 2C19, and 2J2 were detected in all individuals and ranged from 8.8 to 150, 2.9 to 27, <0.6 to 3.9, and <0.2 to 3.1 pmol/mg, respectively. CYP2D6 was detected in 29 individuals and ranged from <0.2 to 1.4 pmol/mg. CYP3A5 was detected readily in 11 individuals, with a range (average) of 4.9 to 25 (16) pmol/mg that represented from 3 to 50% of total CYP3A (CYP3A4 + CYP3A5) content. CYP1A1 was detected readily in three individuals, with a range (average) of 3.6 to 7.7 (5.6) pmol/mg. P450s 1A2, 2A6, 2B6, 2C8, and 2E1 were not or only faintly detected. As anticipated, average CYP3A content (50 pmol/mg) was the highest. Excluding CYP1A1, the remaining enzymes had the following rank order: 2C9 > 2C19 > 2J2 > 2D6 (8.4, 1.1, 0.9, and 0.5 pmol/mg, respectively). Analysis of a pooled preparation of the 31 donor specimens substantiated these results. In summary, as in the liver, large interindividual variation exists in the expression levels of individual P450s. On average, CYP3A and CYP2C9 represents the major pieces of the intestinal P450 pie, accounting for 80 and 15%, respectively, of total immunoquantified P450s.

Paine, Mary F.; Hart, Heather L.; Ludington, Shana S.; Haining, Robert L.; Rettie, Allan E.; Zeldin, Darryl C.

2007-01-01

70

Metabolism of hibifolin by human intestinal bacteria.  

PubMed

Hibifolin, the highest-content bioactive flavonoid of the flowers of Abelmoschus manihot, was incubated with human intestinal bacteria, and four metabolites (1-4) were obtained from the incubated solution by chromatographic methods. The structures of the four metabolites were elucidated as gossypetin 8-O-beta-D-4''-deoxy- Delta(4'')-glucuropyranoside (1), gossypetin (2), quercetin (3), and 8-methoxy-quercetin (4), respectively, on the basis of UV, NMR, and MS data. Metabolite 1 was obtained as a new compound with a specific beta-D-4''-deoxy-Delta(4'')-glucuropyranosyl moiety, which was formed through a unique and novel metabolic pathway that has not been reported previously. PMID:19235125

Xu, Tong-Tong; Yang, Xiu-Wei; Wang, Bin; Xu, Wei; Zhao, Yu-Ying; Zhang, Qing-Ying

2009-04-01

71

Inhibition of human intestinal ?-glucosidases by calystegines.  

PubMed

Calystegines are polyhydroxylated nortropane alkaloids found in Convolvulaceae, Solanaceae, and other plant families. These plants produce common fruits and vegetables. The calystegine structures resemble sugars and suggest interaction with enzymes of carbohydrate metabolism. Maltase and sucrase are ?-glucosidases contributing to human carbohydrate degradation in the small intestine. Inhibition of these enzymes by orally administered drugs is one option for treatment of diabetes mellitus type 2. In this study, inhibition of maltase and sucrase by calystegines A3 and B2 purified from potatoes was investigated. In silico docking studies confirmed binding of both calystegines to the active sites of the enzymes. Calystegine A3 showed low in vitro enzyme inhibition; calystegine B2 inhibited mainly sucrose activity. Both compounds were not transported by Caco-2 cells indicating low systemic availability. Vegetables rich in calystegine B2 should be further investigated as possible components of a diet preventing a steep increase in blood glucose after a carbohydrate-rich meal. PMID:23697377

Jockovi?, Nebojša; Fischer, Wiebke; Brandsch, Matthias; Brandt, Wolfgang; Dräger, Birgit

2013-06-12

72

[Bacterial community structure in intestine of the white shrimp, Litopenaeus vannamei].  

PubMed

The composition of bacterial community in the intestine of the white shrimp, Litopenaeus vannamei under laboratory culture condition was determined using the 16S rDNA clone library. 16s rRNA gene was amplified and a library was constructed by using the genomic DNA extracted from the bacteria in the shrimp intestine as template. 12 different RFLP patterns of the clones were obtained by restriction fragment length polymorphism analysis using Afa I and Msp I. Compared with the published sequences in GenBank database, sequencing results of cloned 16S rDNA amplicons revealed a diverse community including gamma-proteobacteria and Firmicutes in the intestine of artificial diet-fed shrimp. Results showed that the Firmicutes group can be a dominant component (75.4%) in the shrimp intestinal microflora and other clones belong to gamma-proteobacteria (24.6%) which were identified as Shewanella sp., Pantoea sp., Aranicola sp., Pseudomonas sp. and Vibrio sp., respectively. These results provide the first comprehensive description of microbial diversity of the white shrimp intestine and suggest that most of the bacteria associated with shrimp intestine are uncultured and novel species. PMID:17944366

Li, Ke; Zheng, Tian-ling; Tian, Yun; Yuan, Jian-jun

2007-08-01

73

A Revised Model for Dosimetry in the Human Small Intestine  

SciTech Connect

A new model for an adult human gastrointestinal tract (GIT) has been developed for use in internal dose estimations to the wall of the GIT and to the other organs and tissues of the body from radionuclides deposited in the lumenal contents of the five sections of the GIT. These sections were the esophasgus, stomach, small intestine, upper large intestine, and the lower large intestine. The wall of each section was separated from its lumenal contents.

John Poston; Nasir U. Bhuiyan; R. Alex Redd; Neil Parham; Jennifer Watson

2005-02-28

74

Vasoactive intestinal peptide in human nasal mucosa.  

PubMed Central

Vasoactive intestinal peptide (VIP), which is present with acetylcholine in parasympathetic nerve fibers, may have important regulatory functions in mucous membranes. The potential roles for VIP in human nasal mucosa were studied using an integrated approach. The VIP content of human nasal mucosa was determined to be 2.84 +/- 0.47 pmol/g wet weight (n = 8) by RIA. VIP-immunoreactive nerve fibers were found to be most concentrated in submucosal glands adjacent to serous and mucous cells. 125I-VIP binding sites were located on submucosal glands, epithelial cells, and arterioles. In short-term explant culture, VIP stimulated lactoferrin release from serous cells but did not stimulate [3H]glucosamine-labeled respiratory glycoconjugate secretion. Methacholine was more potent than VIP, and methacholine stimulated both lactoferrin and respiratory glycoconjugate release. The addition of VIP plus methacholine to explants resulted in additive increases in lactoferrin release. Based upon the autoradiographic distribution of 125I-VIP binding sites and the effects on explants, VIP derived from parasympathetic nerve fibers may function in the regulation of serous cell secretion in human nasal mucosa. VIP may also participate in the regulation of vasomotor tone. Images

Baraniuk, J N; Lundgren, J D; Okayama, M; Mullol, J; Merida, M; Shelhamer, J H; Kaliner, M A

1990-01-01

75

Small bowel bacterial overgrowth in adults: A potential contributor to intestinal failure  

Microsoft Academic Search

Small bowel bacterial overgrowth (SBBO), in which colon-derived bacteria colonize the upper small bowel, is found in a wide\\u000a variety of adult diseases associated with intestinal failure and dysfunction, including short bowel syndrome and other conditions\\u000a following massive bowel resection, dysmotility disorders, and inflammatory bowel disease. SBBO also appears to be relatively\\u000a common in the elderly, in whom it often

Thomas R. Ziegler; Conrad R. Cole

2007-01-01

76

The Intestinal Bacterial Community in the Food Waste-Reducing Larvae of Hermetia illucens  

Microsoft Academic Search

As it is known that food waste can be reduced by the larvae of Hermetia illucens (Black soldier fly, BSF), the scientific and commercial value of BSF larvae has increased recently. We hypothesised that\\u000a the ability of catabolic degradation by BSF larvae might be due to intestinal microorganisms. Herein, we analysed the bacterial\\u000a communities in the gut of BSF larvae

Hyunbum Jeon; Soyoung Park; Jiyoung Choi; Gilsang Jeong; Sang-Beom Lee; Youngcheol Choi; Sung-Jae Lee

2011-01-01

77

Small Intestinal Motility Disturbances and Bacterial Overgrowth in Patients With Liver Cirrhosis and Portal Hypertension  

Microsoft Academic Search

OBJECTIVES:Altered small bowel motility and a high prevalence of small intestinal bacterial overgrowth (SIBO) has been observed in patients with liver cirrhosis. Our aim was to explore the relationship between motility abnormalities, portal hypertension, and SIBO.METHODS:Twenty-four patients with liver cirrhosis were included. Twelve had portal hypertension (PH) and 12 had liver cirrhosis (LC) alone. Child-Pugh score was the same in

Steingerdur Anna Gunnarsdottir; Riadh Sadik; Steven Shev; Magnus Simrén; Henrik Sjövall; Per-Ove Stotzer; Hasse Abrahamsson; Rolf Olsson; Einar S. Bjornsson; Anna Gunnarsdottir

2003-01-01

78

Development of Fatal Intestinal Inflammation in MyD88 Deficient Mice Co-infected with Helminth and Bacterial Enteropathogens  

PubMed Central

Infections with intestinal helminth and bacterial pathogens, such as enteropathogenic Escherichia coli, continue to be a major global health threat for children. To determine whether and how an intestinal helminth parasite, Heligomosomoides polygyrus, might impact the TLR signaling pathway during the response to a bacterial enteropathogen, MyD88 knockout and wild-type C57BL/6 mice were infected with H. polygyrus, the bacterial enteropathogen Citrobacter rodentium, or both. We found that MyD88 knockout mice co-infected with H. polygyrus and C. rodentium developed more severe intestinal inflammation and elevated mortality compared to the wild-type mice. The enhanced susceptibility to C. rodentium, intestinal injury and mortality of the co-infected MyD88 knockout mice were found to be associated with markedly reduced intestinal phagocyte recruitment, decreased expression of the chemoattractant KC, and a significant increase in bacterial translocation. Moreover, the increase in bacterial infection and disease severity were found to be correlated with a significant downregulation of antimicrobial peptide expression in the intestinal tissue in co-infected MyD88 knockout mice. Our results suggest that the MyD88 signaling pathway plays a critical role for host defense and survival during helminth and enteric bacterial co-infection.

Su, Libo; Qi, Yujuan; Zhang, Mei; Weng, Meiqian; Zhang, Xichen; Su, Chienwen; Shi, Hai Ning

2014-01-01

79

Milk sialyllactose influences colitis in mice through selective intestinal bacterial colonization  

PubMed Central

Milk oligosaccharides contribute to the development of the intestinal environment by acting as decoy receptors for pathogens and as prebiotics, which promote the colonization of commensal bacteria. Here, using ?2,3- and ?2,6-sialyltransferase-deficient mice, we investigated the role of the sialylated milk oligosaccharides sialyl(?2,3)lactose and sialyl(?2,6)lactose on mucosal immunity. The exposure of newborn mice to milk containing or deficient in sialyllactose had no impact on the development of mucosal leukocyte populations. However, when challenged by dextran sulfate sodium (DSS) in drinking water, adult mice that had been fostered on sialyl(?2,3)lactose-deficient milk were more resistant to colitis compared with mice fostered on normal milk or sialyl(?2,6)lactose-deficient milk. Analysis of intestinal microbiota showed different colonization patterns depending on the presence or absence of sialyl(?2,3)lactose in the milk. Germ-free mice reconstituted with intestinal microbiota isolated from mice fed on sialyl(?2,3)lactose-deficient milk were more resistant to DSS-induced colitis than germ-free mice reconstituted with standard intestinal microbiota. Thus, exposure to sialyllactose during infancy affects bacterial colonization of the intestine, which influences the susceptibility to DSS-induced colitis in adult mice.

Fuhrer, Andrea; Sprenger, Norbert; Kurakevich, Ekaterina; Borsig, Lubor; Chassard, Christophe

2010-01-01

80

Milk sialyllactose influences colitis in mice through selective intestinal bacterial colonization.  

PubMed

Milk oligosaccharides contribute to the development of the intestinal environment by acting as decoy receptors for pathogens and as prebiotics, which promote the colonization of commensal bacteria. Here, using ?2,3- and ?2,6-sialyltransferase-deficient mice, we investigated the role of the sialylated milk oligosaccharides sialyl(?2,3)lactose and sialyl(?2,6)lactose on mucosal immunity. The exposure of newborn mice to milk containing or deficient in sialyllactose had no impact on the development of mucosal leukocyte populations. However, when challenged by dextran sulfate sodium (DSS) in drinking water, adult mice that had been fostered on sialyl(?2,3)lactose-deficient milk were more resistant to colitis compared with mice fostered on normal milk or sialyl(?2,6)lactose-deficient milk. Analysis of intestinal microbiota showed different colonization patterns depending on the presence or absence of sialyl(?2,3)lactose in the milk. Germ-free mice reconstituted with intestinal microbiota isolated from mice fed on sialyl(?2,3)lactose-deficient milk were more resistant to DSS-induced colitis than germ-free mice reconstituted with standard intestinal microbiota. Thus, exposure to sialyllactose during infancy affects bacterial colonization of the intestine, which influences the susceptibility to DSS-induced colitis in adult mice. PMID:21098096

Fuhrer, Andrea; Sprenger, Norbert; Kurakevich, Ekaterina; Borsig, Lubor; Chassard, Christophe; Hennet, Thierry

2010-12-20

81

Nitroreduction and formation of hemoglobin adducts in rats with a human intestinal microflora.  

PubMed Central

In the covalent binding of nitroarenes to macromolecules, nitroreduction is an important step. The intestinal microflora represents an enormous potential of bacterial nitroreductase activity. As a consequence, the in vivo nitroreduction of orally administered nitroarenes is primarily located in the intestine. In this study, we have investigated the nitroreduction of 2-nitrofluorene (2-NF) by a human microflora in female Wistar rats. Germ-free (GF) rats were equipped with a bacterial flora derived from human feces. Nontreated GF rats and GF animals equipped with a conventional rat flora were used as controls. The composition of the human and the conventional microflora isolated from the rats were consistent with the microflora of the administered feces. In the rats receiving only sunflower seed oil, no adducts were detected. The animals equipped with a human or rat microflora that received 2-aminofluorene (2-AF) formed 2-AF hemoglobin (Hb)-adducts at average levels (mean +/- SEM) of 5.3 +/- 0.3 and 6.7 +/- 0.7 mumole/g Hb, respectively. After 2-NF administration, the adduct levels were 0.022 +/- 0.003 and 0.043 +/- 0.010 mumole/g Hb, respectively. In the GF rats, an adduct level of 0.57 +/- 0.09 was determined after 2-AF administration and no adducts were detected after 2-NF administration. The results show that nitroreduction by an acquired human intestinal microflora and subsequent adduct formation can be studied in the rat in vivo.

Scheepers, P T; Straetemans, M M; Koopman, J P; Bos, R P

1994-01-01

82

Over-starvation aggravates intestinal injury and promotes bacterial and endotoxin translocation under high-altitude hypoxic environment  

PubMed Central

AIM: To study whether over-starvation aggravates intestinal mucosal injury and promotes bacterial and endotoxin translocation in a high-altitude hypoxic environment. METHODS: Sprague-Dawley rats were exposed to hypobaric hypoxia at a simulated altitude of 7000 m for 72 h. Lanthanum nitrate was used as a tracer to detect intestinal injury. Epithelial apoptosis was observed with terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Serum levels of diamino oxidase (DAO), malondialdehyde (MDA), glutamine (Gln), superoxide dismutase (SOD) and endotoxin were measured in intestinal mucosa. Bacterial translocation was detected in blood culture and intestinal homogenates. In addition, rats were given Gln intragastrically to observe its protective effect on intestinal injury. RESULTS: Apoptotic epithelial cells, exfoliated villi and inflammatory cells in intestine were increased with edema in the lamina propria accompanying effusion of red blood cells. Lanthanum particles were found in the intercellular space and intracellular compartment. Bacterial translocation to mesenteric lymph nodes (MLN) and spleen was evident. The serum endotoxin, DAO and MDA levels were significantly higher while the serum SOD, DAO and Gln levels were lower in intestine (P < 0.05). The bacterial translocation number was lower in the high altitude hypoxic group than in the high altitude starvation group (0.47 ± 0.83 vs 2.38 ± 1.45, P < 0.05). The bacterial translocation was found in each organ, especially in MLN and spleen but not in peripheral blood. The bacterial and endotoxin translocations were both markedly improved in rats after treatment with Gln. CONCLUSION: High-altitude hypoxia and starvation cause severe intestinal mucosal injury and increase bacterial and endotoxin translocation, which can be treated with Gln.

Zhou, Qi-Quan; Yang, Ding-Zhou; Luo, Yong-Jun; Li, Su-Zhi; Liu, Fu-Yu; Wang, Guan-Song

2011-01-01

83

Intestinal and hepatic metabolism of glutamine and citrulline in humans  

PubMed Central

Glutamine plays an important role in nitrogen homeostasis and intestinal substrate supply. It has been suggested that glutamine is a precursor for arginine through an intestinal–renal pathway involving inter-organ transport of citrulline. The importance of intestinal glutamine metabolism for endogenous arginine synthesis in humans, however, has remained unaddressed. The aim of this study was to investigate the intestinal conversion of glutamine to citrulline and the effect of the liver on splanchnic citrulline metabolism in humans. Eight patients undergoing upper gastrointestinal surgery received a primed continuous intravenous infusion of [2-15N]glutamine and [ureido-13C–2H2]citrulline. Arterial, portal venous and hepatic venous blood were sampled and portal and hepatic blood flows were measured. Organ specific amino acid uptake (disposal), production and net balance, as well as whole body rates of plasma appearance were calculated according to established methods. The intestines consumed glutamine at a rate that was dependent on glutamine supply. Approximately 13% of glutamine taken up by the intestines was converted to citrulline. Quantitatively glutamine was the only important precursor for intestinal citrulline release. Both glutamine and citrulline were consumed and produced by the liver, but net hepatic flux of both amino acids was not significantly different from zero. Plasma glutamine was the precursor of 80% of plasma citrulline and plasma citrulline in turn was the precursor of 10% of plasma arginine. In conclusion, glutamine is an important precursor for the synthesis of arginine after intestinal conversion to citrulline in humans.

van de Poll, Marcel C G; Ligthart-Melis, Gerdien C; Boelens, Petra G; Deutz, Nicolaas E P; van Leeuwen, Paul A M; Dejong, Cornelis H C

2007-01-01

84

Human intestinal spirochaetosis in northern Japan.  

PubMed

A histological diagnosis of human intestinal spirochaetosis (HIS) was made in 114 patients during the period 1994-2007. All patients lived in three prefectures in the northern part of Honshu, Japan. Most patients were elderly and male. Twenty-nine patients complained of abdominal pain, bloody stools, diarrhoea or bowel symptoms, but most patients showed no direct symptoms of bowel disease, and occult faecal blood detected at medical check-up was the main reason for colonoscopic examination. There were no homosexual patients and no immunosuppressed patients. HIS was evenly distributed throughout the whole colorectum. PCR analysis of Brachyspira aalborgi and Brachyspira pilosicoli revealed that more patients were infected with B. aalborgi. Follow-up PCR studies confirmed that infestation with B. aalborgi could be repeatedly detected over a 6 year period. This study, involving over 100 patients, identified the characteristic features of HIS in northern Japan. The results suggest that these spirochaetes may be harmless commensals that cause no obvious pathological alterations in infected individuals. PMID:20378723

Sato, Hajime; Nakamura, Shin-ichi; Habano, Wataru; Wakabayashi, Go; Adachi, Yoshikazu

2010-07-01

85

Unregulated smooth-muscle myosin in human intestinal neoplasia  

Microsoft Academic Search

A recent study described a recessive ATPase activating germ-line mutation in smooth-muscle myosin (smmhc\\/myh11) underlying the zebrafish meltdown (mlt) phenotype. The mlt zebrafish develops intestinal abnormalities reminiscent of human Peutz-Jeghers syndrome (PJS) and juvenile polyposis (JP). To examine the role of MYH11 in human intestinal neoplasia, we searched for MYH11 mutations in patients with colorectal cancer (CRC), PJS and JP.

Pia Alhopuro; Denis Phichith; Sari Tuupanen; Heli Sammalkorpi; Miranda Nybondas; Juha Saharinen; James P. Robinson; Zhaohui Yang; Li-Qiong Chen; Torben Orntoft; Jukka-Pekka Mecklin; Heikki Järvinen; Charis Eng; Gabriela Moeslein; Darryl Shibata; Richard S. Houlston; Anneke Lucassen; Ian P. M. Tomlinson; Virpi Launonen; Ari Ristimäki; Diego Arango; Auli Karhu; H. Lee Sweeney; Lauri A. Aaltonen

2008-01-01

86

Purification and fermentation in vitro of sesaminol triglucoside from sesame cake by human intestinal microbiota.  

PubMed

Sesaminol triglucoside (STG), the most abundant lignan glycoside existing in sesame cake/meal, has exhibited various biological activities. However, little information about its in vitro fermentation with intestinal microbiota is available. Therefore, the effect of STG from sesame cake on the fermentation of human fecal microbiota was evaluated. First, high-purity STG was successfully prepared from defatted sesame cake by extraction with 80% ethanol and simple purification procedures of polyamide column chromatography and Toyopearl HW-40S column chromatography. Then the influence of STG on intestinal microbiota was conducted by monitoring bacterial populations and analyzing the concentrations of short-chain fatty acids (SCFA). We found that STG could significantly induce an increase in numbers of Lactobacillus - Enterococcus group and Bifidobacterium in fermentation in vitro with human fecal microbiota, while it did not stimulate the bacterial growth of Eubacterium rectale - Clostridium coccoides group, Clostridium histolyticum group, and Bacteroides - Prevotella group. Furthermore, it was found that concentrations of formic, acetic, propionic, and butyric acids in STG culture increased significantly during the fermentation, and its total SCFA concentration was relatively higher than those of the control and glucose cultures at 6 and 12 h fermentation. Our findings provided further evidence for the importance of human intestinal bacteria in the bioactivity of STG and its metabolites in the maintenance of human health. PMID:23387872

Zhu, Xiuling; Zhang, Xin; Sun, Yongkang; Su, Di; Sun, Yi; Hu, Bing; Zeng, Xiaoxiong

2013-02-27

87

Halophilic archaea in the human intestinal mucosa.  

PubMed

The human gastrointestinal tract microbiota, despite its key roles in health and disease, remains a diverse, variable and poorly understood entity. Current surveys reveal a multitude of undefined bacterial taxa and a low diversity of methanogenic archaea. In an analysis of the microbiota in colonic mucosal biopsies from patients with inflammatory bowel disease we found 16S rDNA sequences representing a phylogenetically rich diversity of halophilic archaea from the Halobacteriaceae (haloarchaea), including novel phylotypes. As the human colon is not considered a salty environment and haloarchaea are described as extreme halophiles, we evaluated and further discarded the possibility that these sequences originated from pre-colonoscopy saline lavage solutions. Furthermore, aerobic enrichment cultures prepared from a patient biopsy at low salinity (2.5% NaCl) yielded haloarchaeal sequence types. Microscopic observation after fluorescence in situ hybridization provided evidence of the presence of viable archaeal cells in these cultures. These results prove the survival of haloarchaea in the digestive system and suggest that they may be members of the mucosal microbiota, even if present in low numbers in comparison with methanogenic archaea. Investigation of a potential physiological basis of this association may lead to new insights into gastrointestinal health and disease. PMID:20438582

Oxley, Andrew P A; Lanfranconi, Mariana P; Würdemann, Dieco; Ott, Stephan; Schreiber, Stefan; McGenity, Terry J; Timmis, Kenneth N; Nogales, Balbina

2010-09-01

88

Bacterial biogeography of the human digestive tract  

PubMed Central

We present bacterial biogeography as sampled from the human gastrointestinal tract of four healthy subjects. This study generated >32 million paired-end sequences of bacterial 16S rRNA genes (V3 region) representing >95,000 unique operational taxonomic units (OTUs; 97% similarity clusters), with >99% Good's coverage for all samples. The highest OTU richness and phylogenetic diversity was found in the mouth samples. The microbial communities of multiple biopsy sites within the colon were highly similar within individuals and largely distinct from those in stool. Within an individual, OTU overlap among broad site definitions (mouth, stomach/duodenum, colon and stool) ranged from 32–110 OTUs, 25 of which were common to all individuals and included OTUs affiliated with Faecalibacterium prasnitzii and the TM7 phylum. This first comprehensive characterization of the abundant and rare microflora found along the healthy human digestive tract represents essential groundwork to investigate further how the human microbiome relates to health and disease.

Stearns, Jennifer C.; Lynch, Michael D. J.; Senadheera, Dilani B.; Tenenbaum, Howard C.; Goldberg, Michael B.; Cvitkovitch, Dennis G.; Croitoru, Kenneth; Moreno-Hagelsieb, Gabriel; Neufeld, Josh D.

2011-01-01

89

Bacterial Overgrowth  

Microsoft Academic Search

\\u000a The human gastrointestinal tract typically contains 300–500 bacterial species. Most bacterial species are acquired during\\u000a the birth process and although some changes to the flora may occur during later stages of life, the composition of the intestinal\\u000a microflora remains relatively constant. Small bowel bacterial overgrowth (SBBO) is defined as an excessive increase in the\\u000a number of bacteria in the upper

Rosemary J. Young; Jon A. Vanderhoof

90

Bacterial biofilms associated with food particles in the human large bowel.  

PubMed

Bacteria within the gastro-intestinal tract affect host function via production of short-chain fatty acids and synthesis of vitamins. Additionally, the commensal enteric bacteria modulate the immune system and provide protection from potentially pathogenic bacteria. Only recently heterogeneous bacterial biofilms were found to be associated with food particles within the intestinal tract. There are a number of studies investigating the formation and function of pathogenic and single-species biofilms, though few studies have investigated the dynamics of multispecies biofilms, especially with regard to food/microbial/host interactions. The scope of this review is to discuss the current knowledge of bacterial biofilms associated with food particles in the human large bowel, examine the established mathematical models depicting bacterial attachment, and elucidate key areas for further research. PMID:21638777

Van Wey, Amy S; Cookson, Adrian L; Roy, Nicole C; McNabb, Warren C; Soboleva, Tanya K; Shorten, Paul R

2011-07-01

91

Intestinal bacterial translocation in rats with cirrhosis is related to compromised Paneth cell antimicrobial host defense.  

PubMed

Liver cirrhosis is associated with bacterial translocation (BT) and endotoxemia. Most translocating bacteria belong to the common intestinal microbiota, suggesting a breakdown of intestinal barrier function. We hypothesized that diminished mucosal antimicrobial host defense could predispose to BT. Two rodent models of portal hypertension with increased BT were used, CCl(4)-induced ascitic cirrhosis and 2-day portal vein-ligated (PVL) animals. BT was assessed by standard microbiological techniques on mesenteric lymph nodes. Total RNA was isolated systematically throughout the intestinal tract, and expression of Paneth cell ?-cryptdins and ?-defensins was determined by real-time quantitative polymerase chain reaction (qPCR). To determine functional consequences, mucosal antimicrobial activity was assessed with a fluorescence-activated cell sorting assay. BT was detectable in 40% of rats with cirrhosis. Compared with the group without BT, these animals exhibited diminished intestinal Paneth cell ?-cryptdin 5 and 7 expression. In contrast, PVL was associated with BT in all animals but did not affect antimicrobial peptides. The decrease in Paneth cell antimicrobials was most pronounced in the ileum and the coecum. Other antimicrobials showed no changes or even an induction in the case of BT at different sites. Antimicrobial activity toward different commensal strains was reduced, especially in the distal ileum and the cecum in experimental cirrhosis with BT (excluding PVL). Conclusion: Compromised Paneth cell antimicrobial host defense seems to predispose to BT in experimental cirrhosis. Understanding this liver-gut axis including the underlying mechanisms could help us to find new treatment avenues. PMID:22095436

Teltschik, Zora; Wiest, Reiner; Beisner, Julia; Nuding, Sabine; Hofmann, Claudia; Schoelmerich, Juergen; Bevins, Charles L; Stange, Eduard F; Wehkamp, Jan

2012-04-01

92

Human intestinal spirochetosis in Japan; its incidence, clinicopathologic features, and genotypic identification  

Microsoft Academic Search

Human intestinal spirochetosis is a common condition in Western countries, but is not well recognized in Japan. To demonstrate the incidence and clinicopathologic findings of human intestinal spirochetosis in Japan, we retrospectively investigated biopsy, and endoscopically or surgically resected specimens of the large intestine. Among a series of 2556 samples, 11 cases of human intestinal spirochetosis were detected (0.4%). Together

Jin Tanahashi; Tsutomu Daa; Ayako Gamachi; Kenji Kashima; Yoshiyuki Kondoh; Naomi Yada; Shigeo Yokoyama

2008-01-01

93

Prebiotic effects of almonds and almond skins on intestinal microbiota in healthy adult humans.  

PubMed

Almonds and almond skins are rich in fiber and other components that have potential prebiotic properties. In this study we investigated the prebiotic effects of almond and almond skin intake in healthy humans. A total of 48 healthy adult volunteers consumed a daily dose of roasted almonds (56 g), almond skins (10 g), or commercial fructooligosaccharides (8 g) (as positive control) for 6 weeks. Fecal samples were collected at defined time points and analyzed for microbiota composition and selected indicators of microbial activity. Different strains of intestinal bacteria had varying degrees of growth sensitivity to almonds or almond skins. Significant increases in the populations of Bifidobacterium spp. and Lactobacillus spp. were observed in fecal samples as a consequence of almond or almond skin supplementation. However, the populations of Escherichia coli did not change significantly, while the growth of the pathogen Clostridum perfringens was significantly repressed. Modification of the intestinal microbiota composition induced changes in bacterial enzyme activities, specifically a significant increase in fecal ?-galactosidase activity and decreases in fecal ?-glucuronidase, nitroreductase and azoreductase activities. Our observations suggest that almond and almond skin ingestion may lead to an improvement in the intestinal microbiota profile and a modification of the intestinal bacterial activities, which would induce the promotion of health beneficial factors and the inhibition of harmful factors. Thus we believe that almonds and almond skins possess potential prebiotic properties. PMID:24315808

Liu, Zhibin; Lin, Xiuchun; Huang, Guangwei; Zhang, Wen; Rao, Pingfan; Ni, Li

2014-04-01

94

Small intestinal MUC2 synthesis in human preterm infants.  

PubMed

Mucin 2 (MUC2) is the structural component of the intestinal protective mucus layer, which contains high amounts of threonine in its peptide backbone. MUC2 synthesis rate might be a potential parameter for intestinal barrier function. In this study, we aimed to determine whether systemic threonine was used for small intestinal MUC2 synthesis and to calculate the MUC2 fractional synthetic rate (FSR) in human preterm infants. Seven preterm infants with an enterostomy following bowel resection for necrotizing enterocolitis received intravenous infusion of [U-(13)C]threonine to determine incorporation of systemic threonine into secreted MUC2 in intestinal outflow fluid. Small intestinal MUC2 was isolated using cesium chloride gradient ultracentrifugation and gravity gel filtration chromatography. MUC2-containing fractions were identified by SDS-PAGE/periodic acid-Schiff staining and Western blot analysis and were subsequently pooled. Isotopic enrichment of threonine, measured in MUC2 using gas chromatography isotopic ratio mass spectrometry, was used to calculate the FSR of MUC2. Systemically derived threonine was indeed incorporated into small intestinal MUC2. Median FSR of small intestinal MUC2 was 67.2 (44.3-103.9)% per day. Systemic threonine is rapidly incorporated into MUC2 in the small intestine of preterm infants, and thereby MUC2 has a very high synthesis rate. PMID:19246635

Schaart, Maaike W; de Bruijn, Adrianus C J M; Schierbeek, Henk; Tibboel, Dick; Renes, Ingrid B; van Goudoever, Johannes B

2009-05-01

95

Gastrointestinal complaints in runners are not due to small intestinal bacterial overgrowth  

Microsoft Academic Search

Background  Gastrointestinal complaints are common among long distance runners. We hypothesised that small intestinal bacterial overgrowth\\u000a (SIBO) is present in long distance runners frequently afflicted with gastrointestinal complaints.\\u000a \\u000a \\u000a \\u000a \\u000a Findings  Seven long distance runners (5 female, mean age 29.1 years) with gastrointestinal complaints during and immediately after\\u000a exercise without known gastrointestinal diseases performed Glucose hydrogen breath tests for detection of SIBO one week

Kai Schommer; Dejan Reljic; Peter Bärtsch; Peter Sauer

2011-01-01

96

Bacterial Growth in Human Vitreous Humor  

Microsoft Academic Search

The aim of this study was to investigate the capacity of human vitreous to support bacterial growth and to show differences in the growth kinetics of gram-positive and gram-negative bacteria. Vitreous gel of 70 keratoplasty donor eyes was sampled under sterile conditions, screened microscopically for cellular components and tested for sterility and levels of antibiotic drugs by bio-assay. The samples

S. F EGGER; A BUXBAUM; M GEORGOPOULOS; C SCHOLDA; V. P VECSEI; V HUBER-SPITZY; A GEORGOPOULOS

1997-01-01

97

Distribution of vasoactive intestinal polypeptide and substance P receptors in human colon and small intestine  

SciTech Connect

Vasoactive intestinal polypeptide (VIP) and substance P are found in neurons in the lamina propria and submucosa and muscularis propria of human small intestine and colon. VIP receptors coupled to adenylate cyclase are present on epithelial, smooth muscle, and mononuclear cells. This study analyzes the distribution of (/sup 125/I)VIP binding and (/sup 125/I)substance P in human colon and small intestine using autoradiographic techniques. (/sup 125/I)VIP binding was present in high density in the mucosal layer of colon and small intestine. (/sup 125/I)VIP binding was not significantly greater than nonspecific binding in smooth muscle layers or the lymphoid follicles. In contrast, (/sup 125/I)substance P binding was present in high density over the colonic muscle but was not present over the mucosal layer. In human colon cancer, (/sup 125/I)VIP grain density over the malignant tissue was only slightly higher than background. These autoradiographic studies of (/sup 125/I)VIP binding indicate that the highest density of VIP receptors was found in the small intestine and superficial colonic mucosa, whereas the density of substance P receptors was highest over the smooth muscle layers. These findings suggest a mismatch between immunochemical content of the peptide and autoradiographic density of the receptor.

Korman, L.Y.; Sayadi, H.; Bass, B.; Moody, T.W.; Harmon, J.W.

1989-07-01

98

The Small Intestine in Human Schistosomiasis.  

National Technical Information Service (NTIS)

The 13 patients with intestinal schistosomiasis, aged 18 to 41 years, presented the primary complaints of diarrhea and weakness. The 24-hr excretion of the ova of S. mansoni in the stool ranged from 10,725 to 696,475 (mean 241,441 plus or minus SEM 53,475...

C. H. Halsted S. Sheir F. O. Raasch

1969-01-01

99

Ecophysiology of the Developing Total Bacterial and Lactobacillus Communities in the Terminal Small Intestine of Weaning Piglets  

Microsoft Academic Search

Weaning of the pig is generally regarded as a stressful event which could lead to clinical implications because of the changes\\u000a in the intestinal ecosystem. The functional properties of microbiota inhabiting the pig’s small intestine (SI), including\\u000a lactobacilli which are assumed to exert health-promoting properties, are yet poorly described. Thus, we determined the ecophysiology\\u000a of bacterial groups and within genus

Robert Pieper; Pawel Janczyk; Annette Zeyner; Hauke Smidt; Volker Guiard; Wolfgang Bernhard Souffrant

2008-01-01

100

Investigation of chicken intestinal bacterial communities by 16S rRNA targeted fluorescence in situ hybridization  

Microsoft Academic Search

The aim of the investigation was to quantify selected dominant bacterial groups in the chicken intestinal tract. Conventional\\u000a production was used as model and the effect of the supplement with Salinomycin was evaluated. Hybridization conditions were\\u000a optimized for published probes with respect to a panel of reference bacteria. In chicken intestinal samples bacteria were\\u000a quantified by fluorescence in situ hybridization

K. N. Olsen; M. Henriksen; M. Bisgaard; O. L. Nielsen; H. Christensen

2008-01-01

101

Large intestine bacterial flora of nonhibernating and hibernating leopard frogs (Rana pipiens).  

PubMed Central

The bacteria in the large intestines of 10 northern leopard frogs (Rana pipiens) were enumerated and partially characterized. Four nonhibernating frogs were collected in the summer, four hibernating frogs were collected in the winter, and two frogs just emerged from hibernation were collected in the spring. All frogs had about 10(10) bacteria per g (wet weight) of intestinal contents and about 10(9) bacteria per g (wet weight) of mucosal scraping, although the counts from the winter frogs were slightly less than those from the other two groups of frogs. Another group of 14 summer frogs, after treatment to induce hibernation, showed a drop in bacterial counts accompanied by a change in the composition of the flora. In most frogs, Bacteroides was the dominant organism. Other bacteria repeatedly isolated at high dilutions were strict anaerobes, including butyrigenic and acetogenic helically coiled bacteria; fusobacteria; and acetogenic, small, gram-positive bacilli. These data indicate that the intestinal flora of frogs is similar to that of mammals and birds and that this flora can be maintained at temperatures close to freezing.

Gossling, J; Loesche, W J; Nace, G W

1982-01-01

102

Evaluation of impact of exposure of Sudan azo dyes and their metabolites on human intestinal bacteria.  

PubMed

Sudan azo dyes are banned for food usage in most countries, but they are illegally used to maintain or enhance the color of food products due to low cost, bright staining, and wide availability of the dyes. In this report, we examined the toxic effects of these azo dyes and their potential reduction metabolites on 11 prevalent human intestinal bacterial strains. Among the tested bacteria, cell growth of 2, 3, 5, 5, and 1 strains was inhibited by Sudan I, II, III, IV, and Para Red, respectively. At the tested concentration of 100 ?M, Sudan I and II inhibited growth of Clostridium perfringens and Lactobacillus rhamnosus with decrease of growth rates from 14 to 47%. Sudan II also affected growth of Enterococcus faecalis. Growth of Bifidobacterium catenulatum, C. perfringens, E. faecalis, Escherichia coli, and Peptostreptococcus magnus was affected by Sudan III and IV with decrease in growth rates from 11 to 67%. C. perfringens was the only strain in which growth was affected by Para Red with 47 and 26% growth decreases at 6 and 10 h, respectively. 1-Amino-2-naphthol, a common metabolite of the dyes, was capable of inhibiting growth of most of the tested bacteria with inhibition rates from 8 to 46%. However, the other metabolites of the dyes had no effect on growth of the bacterial strains. The dyes and their metabolites had less effect on cell viability than on cell growth of the tested bacterial strains. Clostridium indolis and Clostridium ramosum were the only two strains with about a 10 % decrease in cell viability in the presence of Sudan azo dyes. The present results suggested that Sudan azo dyes and their metabolites potentially affect the human intestinal bacterial ecology by selectively inhibiting some bacterial species, which may have an adverse effect on human health. PMID:22634331

Pan, Hongmiao; Feng, Jinhui; He, Gui-Xin; Cerniglia, Carl E; Chen, Huizhong

2012-08-01

103

Imprint cytology detects floating Brachyspira in human intestinal spirochetosis.  

PubMed

Human intestinal spirochetosis is a colorectal infectious disease caused by 2 Brachyspira species. Its diagnosis is established by histology, culture, and polymerase chain reaction, but the value of cytologic examination in routine practice remains unclear. In this study, imprint cytology of biopsy specimens was examined for cytologic features specific to human intestinal spirochetosis. Specimens were obtained from 65 colorectal regions (1-3 regions from each case) in 25 ultrastructurally and/or genetically confirmed human intestinal spirochetosis cases (20 with Brachyspira aalborgi, 3 with B pilosicoli, 2 with both genotypes). In cytologic specimens, spirochetes tended to be floating freely within the mucus and intestinal fluid, whereas the "fringe formation" of spirochetes typically observed in histologic specimens was indistinct in cytologic specimens. Spirochetes were identified in 58 regions (89.2%) and 23 cases (92.0%) by cytology, against in 50 regions (76.9%) and 22 cases (88.0%) by histology (no significant differences). In 6 of 8 regions exhibiting positive cytology and negative histology, B pilosicoli was present within the mucus. Hence, B pilosicoli may tend to float in the mucus. In conclusion, cytologic examination would be useful for the routine identification of human intestinal spirochetosis, especially if B pilosicoli is involved. Further, we suggest the existence of differences in biological behavior between these spirochetes. PMID:19836054

Ogata, Sho; Higashiyama, Masaaki; Adachi, Yoshikazu; Ohara, Ichiyo; Nishiyama, Junichiro; Okusa, Yasushi; Takeo, Hiroaki; Sato, Kimiya; Nakanishi, Kuniaki; Kawai, Toshiaki

2010-02-01

104

Intestinal drug solubility estimation based on simulated intestinal fluids: Comparison with solubility in human intestinal fluids  

Microsoft Academic Search

The purpose of this study was to validate both existing fasted and fed state simulated intestinal fluids (FaSSIF and FeSSIF), and simpler, alternative media for predicting intraluminal drug solubility during drug discovery and early drug development. For 17 model drugs, the solubilizing capacity of FaSSIFc and FeSSIFc (subscript indicates the use of crude taurocholate) and different concentrations of d-?-tocopheryl polyethylene

Sarah Clarysse; Joachim Brouwers; Jan Tack; Pieter Annaert; Patrick Augustijns

2011-01-01

105

Sensitivity of bile acid breath test in the diagnosis of bacterial overgrowth in the small intestine with and without the stagnant (blind) loop syndrome  

Microsoft Academic Search

The bile acid breath test was studied to examine its sensitivity for establishing the diagnosis of bacterial overgrowth in comparison to that of the Schilling test and small-intestinal cultures in 12 patients with a stagnant (blind) loop syndrome, as well as in 38 patients who had other conditions with suspected bacterial contamination of the small intestine. The presence of bile

Sirus Farivar; Hans Fromm; Detlef Schindler; Friedrich W. Schmidt

1979-01-01

106

The influence of fruit ingestion before meals upon the bacterial flora of stomach and large intestine and on food allergins  

Microsoft Academic Search

HE influence of various fruits upon gastro-intestinal function has been studied in this laboratory for the past few years. The intra-alimentary contents, from the oral cavity to the anal opening, depend upon the materials ingested, the fluids secreted, and the bacterial flora in the lumen of this tract. We have been particularly interested in the bacterial flora and the acid-base

Olaf Bergeim; Arthur Hanszen; Lloyd Arnold

1936-01-01

107

Intestinal-fatty acid binding protein and lipid transport in human intestinal epithelial cells  

SciTech Connect

Intestinal-fatty acid binding protein (I-FABP) is a 14-15 kDa cytoplasmic molecule highly expressed in the enterocyte. Although different functions have been proposed for various FABP family members, the specific function of I-FABP in human intestine remains unclear. Here, we studied the role of I-FABP in molecularly modified normal human intestinal epithelial cells (HIEC-6). cDNA transfection resulted in 90-fold I-FABP overexpression compared to cells treated with empty pQCXIP vector. The high-resolution immunogold technique revealed labeling mainly in the cytosol and confirmed the marked phenotype abundance of I-FABP in cDNA transfected cells. I-FABP overexpression was not associated with alterations in cell proliferation and viability. Studies using these transfected cells cultured with [{sup 14}C]oleic acid did not reveal higher efficiency in de novo synthesis or secretion of triglycerides, phospholipids, and cholesteryl esters compared to cells treated with empty pQCXIP vector only. Similarly, the incubation with [{sup 35}S]methionine did not disclose a superiority in the biogenesis of apolipoproteins (apo) A-I, A-IV, B-48, and B-100. Finally, cells transfected with I-FABP did not exhibit an increased production of chylomicrons, VLDL, LDL, and HDL. Our observations establish that I-FABP overexpression in normal HIEC-6 is not related to cell proliferation, lipid esterification, apo synthesis, and lipoprotein assembly, and, therefore, exclude its role in intestinal fat transport.

Montoudis, Alain [Department of Nutrition, Universite de Montreal and Research Center, CHU Sainte Justine, 3175 Cote Ste-Catherine, Montreal, Que., H3T 1C5 (Canada); Delvin, Edgard [Department of Biochemistry, Universite de Montreal and Research Center, CHU Sainte Justine, 3175 Cote Ste-Catherine, Montreal, Que., H3T 1C5 (Canada); Canadian Institute of Health Research, Group of the Functional Development and Physiopathology of the Digestive Tract, and Department of Anatomy and Cellular Biology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Que., Canada J1H 5N4 (Canada); Menard, Daniel [Department of Pathology and Cell Biology, Universite de Montreal and Research Center, CHU Sainte Justine, 3175 Cote Ste-Catherine, Montreal, Que., H3T 1C5 (Canada); Canadian Institute of Health Research, Group of the Functional Development and Physiopathology of the Digestive Tract, and Department of Anatomy and Cellular Biology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Que., J1H 5N4 (Canada)] (and others)

2006-01-06

108

A review on the impact of 4-quinolones on the normal oropharyngeal and intestinal human microflora.  

PubMed

During the last few years the impact of the newer 4-quinolones, ciprofloxacin, enoxacin, norfloxacin, ofloxacin and pefloxacin, on the human microflora has been studied by several investigators. This review article summarizes the published data concerning these studies. The results show that the oropharyngeal flora is affected only slightly or not at all by the 4-quinolones. All the newer 4-quinolones have a similar effect on the normal intestinal flora. The gram-negative aerobic flora is strongly suppressed during administration of 4-quinolones, while the gram-positive flora is only slightly affected. The anaerobic microflora is hardly affected at all. The emergence of resistant bacterial strains is uncommon, although one study shows increased MIC-values for anaerobes during ciprofloxacin administration. Replacement by yeasts or other inherently resistant microorganisms does not often seem to be a problem. High concentrations of the 4-quinolones are reached in faeces, values between 100-2,200 mg/kg being reported. Since the 4-quinolones do not cause marked ecological disturbances in the intestinal microflora, they may be suitable for selective decontamination in immunocompromised patients, for prophylaxis of urinary tract infections and for treatment of bacterial intestinal infections. PMID:3283041

Edlund, C; Nord, C E

1988-01-01

109

Do dietary betaine and the antibiotic florfenicol influence the intestinal autochthonous bacterial community in hybrid tilapia (Oreochromis niloticus ? × O. aureus ?)?  

PubMed

The attractant betaine and the antibiotic growth promoter florfenicol are commonly used together in Chinese fresh water aquaculture, but there is no information about the effect of these two feed additive on the intestinal autochthonous bacterial community in hybrid tilapia (Oreochromis nilotica ? × O. aureas ?). Hybrid tilapia (240 fish in total; 20 fish per net cage; three cages per group) were divided into four dietary groups: control group, no betaine or florfenical addition (CK); betaine group, 0.1% betaine added (B); florfenicol group, 0.002% florfenicol added (F); and combination group, 0.1% betaine and 0.002% florfenicol added together (BF). After 8 weeks of feeding, six fish from each cage were chosen randomly, the guts were sampled and pooled, and their intestinal autochthonous bacterial communities were analyzed by 16S rDNA-denaturing gradient gel electrophoresis. Enumeration of total gut autochthonous bacteria was analyzed by quantitative PCR with rpoB as the endogenous control. The results showed that the fish intestinal bacteria of group B were more diverse than that of CK, and that of F and BF groups was reduced in the total numbers and limited to certain bacterial species or genera (P < 0.05). This study revealed that betaine can promote some intestinal autochthonous bacteria, and florfenicol play a depressor role. When combined together, florfenicol may overshadow the effect of betaine on the predominant intestinal bacteria of tilapia. PMID:22805797

He, Suxu; Zhou, Zhigang; Liu, Yuchun; Cao, Yanan; Meng, Kun; Shi, Penjun; Yao, Bin; Ringø, Einar

2012-03-01

110

The Role of Methane in Intestinal Diseases  

Microsoft Academic Search

The volume of human intestinal gas is about 200 ml, and it is derived from complex physiological processes including swallowed air, diffusion from bloodstream into the lumen, and particularly intraluminal production by chemical reactions and bacterial fermentation. Gas is continuously removed by eructation, anal evacuation, absorption through the intestinal mucosa, and bacterial consumption. More than 99% of it is composed

Davide Roccarina; Ernesto Cristiano Lauritano; Maurizio Gabrielli; Francesco Franceschi; Veronica Ojetti; Antonio Gasbarrini

2010-01-01

111

Toxicological significance of azo dye metabolism by human intestinal microbiota.  

PubMed

Approximately 0.7 million tons of azo dyes are synthesized each year. Azo dyes are composed of one or more R?-N=N-R? linkages. Studies have shown that both mammalian and microbial azoreductases cleave the azo bonds of the dyes to form compounds that are potentially genotoxic. The human gastrointestinal tract harbors a diverse microbiota comprised of at least several thousand species. Both water-soluble and water-insoluble azo dyes can be reduced by intestinal bacteria. Some of the metabolites produced by intestinal microbiota have been shown to be carcinogenic to humans although the parent azo dyes may not be classified as being carcinogenic. Azoreductase activity is commonly found in intestinal bacteria. Three types of azoreductases have been characterized in bacteria. They are flavin dependent NADH preferred azoreductase, flavin dependent NADPH preferred azoreductase, and flavin free NADPH preferred azoreductase. This review highlights how azo dyes are metabolized by intestinal bacteria, mechanisms of azo reduction, and the potential contribution in the carcinogenesis/mutagenesis of the reduction of the azo dyes by intestinal microbiota. PMID:22201895

Feng, Jinhui; Cerniglia, Carl E; Chen, Huizhong

2012-01-01

112

Quantitation of small intestinal permeability during normal human drug absorption  

PubMed Central

Background Understanding the quantitative relationship between a drug’s physical chemical properties and its rate of intestinal absorption (QSAR) is critical for selecting candidate drugs. Because of limited experimental human small intestinal permeability data, approximate surrogates such as the fraction absorbed or Caco-2 permeability are used, both of which have limitations. Methods Given the blood concentration following an oral and intravenous dose, the time course of intestinal absorption in humans was determined by deconvolution and related to the intestinal permeability by the use of a new 3 parameter model function (“Averaged Model” (AM)). The theoretical validity of this AM model was evaluated by comparing it to the standard diffusion-convection model (DC). This analysis was applied to 90 drugs using previously published data. Only drugs that were administered in oral solution form to fasting subjects were considered so that the rate of gastric emptying was approximately known. All the calculations are carried out using the freely available routine PKQuest Java (http://www.pkquest.com) which has an easy to use, simple interface. Results Theoretically, the AM permeability provides an accurate estimate of the intestinal DC permeability for solutes whose absorption ranges from 1% to 99%. The experimental human AM permeabilities determined by deconvolution are similar to those determined by direct human jejunal perfusion. The small intestinal pH varies with position and the results are interpreted in terms of the pH dependent octanol partition. The permeability versus partition relations are presented separately for the uncharged, basic, acidic and charged solutes. The small uncharged solutes caffeine, acetaminophen and antipyrine have very high permeabilities (about 20 x 10-4?cm/sec) corresponding to an unstirred layer of only 45??m. The weak acid aspirin also has a large AM permeability despite its low octanol partition at pH?7.4, suggesting that it is nearly completely absorbed in the first part of the intestine where the pH is about 5.4. Conclusions The AM deconvolution method provides an accurate estimate of the human intestinal permeability. The results for these 90 drugs should provide a useful benchmark for evaluating QSAR models.

2013-01-01

113

Human carboxymethylenebutenolidase as a bioactivating hydrolase of olmesartan medoxomil in liver and intestine.  

PubMed

Olmesartan medoxomil (OM) is a prodrug type angiotensin II type 1 receptor antagonist widely prescribed as an antihypertensive agent. Herein, we describe the identification and characterization of the OM bioactivating enzyme that hydrolyzes the prodrug and converts to its pharmacologically active metabolite olmesartan in human liver and intestine. The protein was purified from human liver cytosol by successive column chromatography and was identified by mass spectrometry to be a carboxymethylenebutenolidase (CMBL) homolog. Human CMBL, whose endogenous function has still not been reported, is a human homolog of Pseudomonas dienelactone hydrolase involved in the bacterial halocatechol degradation pathway. The ubiquitous expression of human CMBL gene transcript in various tissues was observed. The recombinant human CMBL expressed in mammalian cells was clearly shown to activate OM. By comparing the enzyme kinetics and chemical inhibition properties between the recombinant protein and human tissue preparations, CMBL was demonstrated to be the primary OM bioactivating enzyme in the liver and intestine. The recombinant CMBL also converted other prodrugs having the same ester structure as OM, faropenem medoxomil and lenampicillin, to their active metabolites. CMBL exhibited a unique sensitivity to chemical inhibitors, thus, being distinguishable from other known esterases. Site-directed mutagenesis on the putative active residue Cys(132) of the recombinant CMBL caused a drastic reduction of the OM-hydrolyzing activity. We report for the first time that CMBL serves as a key enzyme in the bioactivation of OM, hydrolyzing the ester bond of the prodrug type xenobiotics. PMID:20177059

Ishizuka, Tomoko; Fujimori, Izumi; Kato, Mitsunori; Noji-Sakikawa, Chisa; Saito, Motoko; Yoshigae, Yasushi; Kubota, Kazuishi; Kurihara, Atsushi; Izumi, Takashi; Ikeda, Toshihiko; Okazaki, Osamu

2010-04-16

114

Extremely low electrical current generated by porcine small intestine smooth muscle alters bacterial autolysin production.  

PubMed

The effect of extremely low electrical currents, identical to those generated by the gut smooth muscle, on bacterial autolysin production in vitro was tested in the present study. When stimulated with these electrical currents, the bacteria Pediococcus pentosaceus 16:1 produced groups of peptidoglycan hydrolases that differed from those produced by the unstimulated (control) bacteria. The autolysins synthesized by the P. pentosaceus 16:1 under extremely low electrical currents were effective against peptidoglycans from the cell walls of various lactic acid bacteria strains, whereas the autolysins from the control bacteria acted exclusively against P. pentosaceus 16:1 cell walls. Thus, it can be predicted that in vivo the electrical currents generated by the intestinal smooth muscles, which can be recorded as the myoelectrical migrating complexes, could regulate lactic acid bacteria strain growth in the gut. PMID:16118236

Kruszewska, Danuta; Podgurniak, Pawel; Ljungh, Asa; Sebastian, Aleksandra; Larsson, Lennart; Zajdel-Dabrowska, Jolanta; Pierzynowski, Stefan G

2005-11-01

115

Identification of astilbin metabolites produced by human intestinal bacteria using UPLC-Q-TOF/MS.  

PubMed

Astilbin, mainly isolated from a commonly used herbal medicine, Smilax glabra Roxb (SGR), exhibits a variety of pharmacological activities and biological effects. It is metabolized by intestinal bacteria after oral administration which leads to the variation of ethnopharmacological profile of this traditional medicine. However, little is known on the interactions of this active compound with intestinal bacteria, which would be very helpful in unravelling how SGR works. In this study, different pure bacteria from human feces were isolated and were used to investigate their conversion capability of astilbin. Ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technique combined with Metabolynx(TM) software was used to analyze astilbin and its metabolites. The parent compound and two metabolites (quercetin and eriodictyol) were detected in the isolated bacterial samples compared with blank samples. Quercetin was present in Enterococcus sp. 8B, 8-2 and 9-2 samples. Eriodictyol was only identified in Enterococcus sp. 8B sample. The metabolic routes and metabolites of astilbin produced by the different intestinal bacteria are reported for the first time. This will be useful for the investigation of the pharmacokinetic study of astilbin in vivo and the role of different intestinal bacteria in the metabolism of natural compounds. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24399635

Zhao, Min; Xu, Jun; Qian, Dawei; Guo, Jianming; Jiang, Shu; Shang, Er-Xin; Duan, Jin-Ao

2014-07-01

116

The ex vivo response of human intestinal mucosa to enteropathogenic Escherichia coli infection  

PubMed Central

Summary In vitro organ culture (IVOC) represents a gold standard model to study enteropathogenic E. coli (EPEC) infection of human intestinal mucosa. However, the optimal examination of the bacterial - host cell interaction requires a directional epithelial exposure, without serosal or cut surface stimulation. A polarised IVOC system (pIVOC) was developed in order to overcome such limitations: apical EPEC infection produced negligible bacterial leakage via biopsy edges, resulted in enhanced colonisation compared to standard IVOC, and showed evidence of bacterial detachment, as in natural rabbit EPEC infections. Examination of mucosal innate immune responses in pIVOC showed both interleukin (IL)-8 mRNA and protein levels were significantly increased after apical EPEC infection. Increased IL-8 levels mainly depended on flagellin expression as fliC-negative EPEC did not elicit a significant IL-8 response despite increased mucosal colonisation compared to wild type EPEC. In addition, apical application of purified flagella significantly increased IL-8 protein levels over non-infected controls. Immunofluorescence staining of EPEC-infected small intestinal biopsies revealed apical and basolateral distribution of Toll-like receptor (TLR) 5 on epithelium suggesting that EPEC can trigger mucosal IL-8 responses by apical flagellin/TLR5 interaction ex vivo and does not require access to the basolateral membrane as postulated in cell culture models.

Schuller, Stephanie; Lucas, Mark; Kaper, James B.; Giron, Jorge A.; Phillips, Alan D.

2009-01-01

117

Ontogeny and prenatal expression of trefoil factor 3\\/ITF in the human intestine  

Microsoft Academic Search

Background: Trefoil factor 3 (TFF3) or intestinal trefoil factor (ITF), a peptide normally expressed and secreted by goblet cells at the mucosal surface of the small intestine and colon, is important for the maintenance and repair of the intestinal mucosal barrier. Aim: To study the ontogeny and developmental expression of TFF3 in human intestine. Subjects: We examined TFF3 expression in

Jing Lin; Ali M. Nadroo; Wei Chen; Ian R. Holzman; Qiu-Xiang Fan; Mark W. Babyatsky

2003-01-01

118

Human intestinal M cells exhibit enterocyte-like intermediate filaments  

PubMed Central

Background—The derivation and ultrastructural composition of M cells covering the lymphoid follicles of Peyer's patches is still unknown. Results from different animal models have shown that there are species specific differences in the composition of intermediate filaments between M cells and neighbouring enterocytes. Little is known, however, about intermediate filaments of human M cells. ?Aims—To compare components of the cytoskeleton of human M cells with those of adjacent absorptive enterocytes. ?Methods—The expression and localisation of different cytokeratins, vimentin, and desmin in M cells was determined on follicle associated epithelia of human appendix using immunohistochemistry and immunogold electron microscopy. ?Results—Cytokeratins specific for human intestinal epithelial cells such as cytokeratins 8, 18, 19, and 20 were expressed in both absorptive enterocytes and M cells with no differences in intensity and cellular distribution between both cell types. Vimentin and desmin, tissue specific markers of either mesenchymal or myogenic cells, as well as other cytokeratins were not detectable in enterocytes or M cells. ?Conclusion—This is the first study on the structure of intermediate filaments in human intestinal M cells. Our results show that in contrast to several animal models, human M cells apparently do not differ from adjacent enterocytes in the composition of their intermediate filament cytoskeleton. The presence of enterocyte like cytokeratins and the absence of other cytokeratins as well as of vimentin and desmin supports the hypothesis of an epithelial origin of human intestinal M cells and suggests that M cells may derive from differentiated enterocytes. ?? Keywords: human intestinal M cells; appendix; cytokeratin; intermediate filaments; follicle associated epithelium

Kucharzik, T; Lugering, N; Schmid, K; Schmidt, M; Stoll, R; Domschke, W

1998-01-01

119

Effects of trapidil on intestinal mucosal barrier function and bacterial translocation after intestinal ischemia and reperfusion in an experimental rat model?  

PubMed Central

Background: Intestinal ischemia and reperfusion may be the primary triggers of mucosal barrier impairment, cytokine expression, and bacterial translocation (BT). Trapidil is a phosphodiesterase and platelet-derived growth factor inhibitor that reduces lipid peroxidation and inhibits the production of cytokines. Objective: The goal of this study was to assess whether trapidil might protect the intestinal epithelial barrier by inhibiting lipid peroxidation and proinflammatory cytokines by testing the effect of trapidil on intestinal barrier function in an experimental ischemia/reperfusion (I/R) rat model. Methods: Trapidil was used in a rat model of intestinal barrier dysfunction caused by intestinal ischemia for 40 minutes followed by reperfusion for 12 hours. To do this, the rats were randomized to 1 of 4 treatment groups, as follows: (1) sham surgery and saline administration (1 mL IV) (Sham group); (2) sham surgery and trapidil administration (8 mg/kg IV) (Sham+T group); (3) I/R and saline administration (1 mL IV) (I/R group); and (4) I/R and trapidil administration (8 mg/kg IV) (I/R+T group). Intestinal barrier function was assessed by histopathologic examination, blood malondialdehyde (MDA) level, and BT. Results: The I/R+T group showed significantly less incidence of BT compared with the I/R group in the liver and reduced median colony count of translocated bacteria in mesenteric lymph nodes, liver, spleen, and peritoneum compared with the I/R group. Furthermore, the mean blood MDA level demonstrated that lipid peroxidation was significantly decreased in the I/R+T group compared with the I/R group. Histopathologic findings revealed that trapidil administration before reperfusion preserved intestinal mucosal integrity and inhibited the infiltration of inflammatory cells into the intestines. Conclusions: In this experimental study, a correlation seemed to exist between intestinal barrier dysfunction and BT. Intestinal barrier dysfunction may allow a large amount of bacteria to pass from the gut to distant organs. Trapidil treatment may inhibit BT by preserving intestinal barrier by inhibiting thromboxane A2, lipid peroxidation, proinflammatory cytokines, and stimulated prostacyclin. Future dose- and time-dependent studies will be helpful in revealing the effects of trapidil on BT.

Colak, Tahsin; Ozturk, Candan; Polat, Ayse; Bagdatoglu, Ozlen; Kanik, Arzu; Turkmenoglu, Ozgur; Aydin, Suha

2003-01-01

120

Campylobacter-Induced Interleukin8 Secretion in Polarized Human Intestinal Epithelial Cells Requires Campylobacter-Secreted Cytolethal Distending Toxin and Toll-Like Receptor-Mediated Activation of NF B  

Microsoft Academic Search

Campylobacter jejuni and Campylobacter coli colonize and infect the intestinal epithelium and cause acute inflammatory diarrhea. The intestinal epithelium serves as a physical barrier to, and a sensor of, bacterial infection by secreting proinflammatory cytokines. This study examined the mechanisms for Campylobacter- induced secretion of the proinflammatory chemokine interleukin-8 (IL-8) by using polarized T84 human colonic epithelial cells as a

Jie Zheng; Jianghong Meng; Shaohua Zhao; Ruby Singh; Wenxia Song

2008-01-01

121

Unregulated smooth-muscle myosin in human intestinal neoplasia.  

PubMed

A recent study described a recessive ATPase activating germ-line mutation in smooth-muscle myosin (smmhc/myh11) underlying the zebrafish meltdown (mlt) phenotype. The mlt zebrafish develops intestinal abnormalities reminiscent of human Peutz-Jeghers syndrome (PJS) and juvenile polyposis (JP). To examine the role of MYH11 in human intestinal neoplasia, we searched for MYH11 mutations in patients with colorectal cancer (CRC), PJS and JP. We found somatic protein-elongating frameshift mutations in 55% of CRCs displaying microsatellite instability and in the germ-line of one individual with PJS. Additionally, two somatic missense mutations were found in one microsatellite stable CRC. These two missense mutations, R501L and K1044N, and the frameshift mutations were functionally evaluated. All mutations resulted in unregulated molecules displaying constitutive motor activity, similar to the mutant myosin underlying mlt. Thus, MYH11 mutations appear to contribute also to human intestinal neoplasia. Unregulated MYH11 may affect the cellular energy balance or disturb cell lineage decisions in tumor progenitor cells. These data challenge our view on MYH11 as a passive differentiation marker functioning in muscle contraction and add to our understanding of intestinal neoplasia. PMID:18391202

Alhopuro, Pia; Phichith, Denis; Tuupanen, Sari; Sammalkorpi, Heli; Nybondas, Miranda; Saharinen, Juha; Robinson, James P; Yang, Zhaohui; Chen, Li-Qiong; Orntoft, Torben; Mecklin, Jukka-Pekka; Järvinen, Heikki; Eng, Charis; Moeslein, Gabriela; Shibata, Darryl; Houlston, Richard S; Lucassen, Anneke; Tomlinson, Ian P M; Launonen, Virpi; Ristimäki, Ari; Arango, Diego; Karhu, Auli; Sweeney, H Lee; Aaltonen, Lauri A

2008-04-01

122

Unregulated smooth-muscle myosin in human intestinal neoplasia  

PubMed Central

A recent study described a recessive ATPase activating germ-line mutation in smooth-muscle myosin (smmhc/myh11) underlying the zebrafish meltdown (mlt) phenotype. The mlt zebrafish develops intestinal abnormalities reminiscent of human Peutz–Jeghers syndrome (PJS) and juvenile polyposis (JP). To examine the role of MYH11 in human intestinal neoplasia, we searched for MYH11 mutations in patients with colorectal cancer (CRC), PJS and JP. We found somatic protein-elongating frameshift mutations in 55% of CRCs displaying microsatellite instability and in the germ-line of one individual with PJS. Additionally, two somatic missense mutations were found in one microsatellite stable CRC. These two missense mutations, R501L and K1044N, and the frameshift mutations were functionally evaluated. All mutations resulted in unregulated molecules displaying constitutive motor activity, similar to the mutant myosin underlying mlt. Thus, MYH11 mutations appear to contribute also to human intestinal neoplasia. Unregulated MYH11 may affect the cellular energy balance or disturb cell lineage decisions in tumor progenitor cells. These data challenge our view on MYH11 as a passive differentiation marker functioning in muscle contraction and add to our understanding of intestinal neoplasia.

Alhopuro, Pia; Phichith, Denis; Tuupanen, Sari; Sammalkorpi, Heli; Nybondas, Miranda; Saharinen, Juha; Robinson, James P.; Yang, Zhaohui; Chen, Li-Qiong; Orntoft, Torben; Mecklin, Jukka-Pekka; Jarvinen, Heikki; Eng, Charis; Moeslein, Gabriela; Shibata, Darryl; Houlston, Richard S.; Lucassen, Anneke; Tomlinson, Ian P. M.; Launonen, Virpi; Ristimaki, Ari; Arango, Diego; Karhu, Auli; Sweeney, H. Lee; Aaltonen, Lauri A.

2008-01-01

123

Molecular Epidemiology of Human Intestinal Amoebas in Iran  

PubMed Central

Many microscopic-based epidemiological surveys on the prevalence of human intestinal pathogenic and non-pathogenic protozoa including intestinal amoeba performed in Iran show a high prevalence of human intestinal amoeba in different parts of Iran. Such epidemiological studies on amoebiasis are confusing, mainly due to recently appreciated distinction between the Entamoeba histolytica, E. dispar and E. moshkovskii. Differential diagnosis can be done by some methods such as PCR-based methods, monoclonal antibodies and the analysis of isoenzyme typing, however the molecular study of these protozoa in Iran is low. Based on molecular studies, it seems that E. dispar is predominant species especially in the central and northern areas of Iran and amoebiasis due to E. histolytica is a rare infection in the country. It is suggested that infection with E. moshkovskii may be common among Iranians. Considering the importance of molecular epidemiology of amoeba in Iran and also the current data, the present study reviews the data currently available on the molecular distribution of intestinal human amoeba in Iran.

Hooshyar, H; Rostamkhani, P; Rezaian, M

2012-01-01

124

Impact of formulation excipients on human intestinal transit.  

PubMed

The accelerating effect of polyethylene glycol 400 on small intestinal transit has been previously reported. The aim of this study was to investigate the influence of other solubility-enhancing excipient, propylene glycol, D-alpha-tocopheryl-polyethylene glycol-1,000 succinate (VitE-TPGS) and Capmul MCM, on human intestinal transit. A 5-g dose of each excipient was administered to seven healthy male subjects. Propylene glycol and VitE-TPGS were administered dissolved in 150 mL water. Capmul MCM was administered in the form of four 000 hard gelatin capsules to mask its taste and then given with 150 mL water. On a separate occasion, 150 mL water was administered as the control. Each formulation was radiolabelled with technetium-99 m to follow its transit using a gamma camera. The mean small intestinal transit times were 234, 207, 241 and 209 min for the control, propylene glycol, VitE-TPGS and Capmul MCM treatments, respectively. Although there were differences in the small intestinal transit times for the excipients investigated compared with the control, none of the results were statistically significant. Unlike polyethylene glycol 400 at the same dose of 5 g, the excipients tested (propylene glycol, VitE-TPGS and Capmul MCM) had little or no impact on small intestinal transit. PMID:16734983

Schulze, Julia D R; Ashiru, Diane A I; Khela, Mandeep K; Evans, David F; Patel, Rajesh; Parsons, Gary E; Coffin, Mark D; Basit, Abdul W

2006-06-01

125

Localization of human intestinal defensin 5 in Paneth cell granules.  

PubMed Central

Antibiotic peptides of higher animals include the defensins, first discovered in phagocytic cells but recently also found to be produced by epithelial cells. We biosynthesized recombinant human intestinal defensin 5 (rHD-5) using the baculovirus-insect cell expression system. Since insect cells process defensin incompletely and secrete the precursor proHD-5, we substituted a methionine for an alanine at a likely processing site to allow selective chemical cleavage with cyanogen bromide, and rHD-5 was used to elicit polyclonal antibodies. By the immunoperoxidase-staining technique, the antibodies selectively stained Paneth cells of the normal adult small intestine. Immunogold electron microscopy further localized HD-5 to the Paneth cell secretory granules. Since some defensins exert activity cytotoxic to mammalian cells, we assayed the effect of rHD-5 on the human intestinal cell lines Caco2 and Int407. proHD-5 did not exert cytotoxic activity, and rHD-5 showed only minimal activity against Int407 and was inert against Caco2. Since Paneth cells release their granules adjacent to the mitotic cells of the intestinal crypts, HD could protect this cell population against invasion and parasitization by microbes.

Porter, E M; Liu, L; Oren, A; Anton, P A; Ganz, T

1997-01-01

126

Exploitation of the host ubiquitin system by human bacterial pathogens.  

PubMed

Ubiquitylation is a crucial post-translational protein modification that regulates several cellular processes in eukaryotes, including inflammatory responses, endocytic trafficking and the cell cycle. Importantly, ubiquitylation also has a central role in modulating eukaryotic defence systems; however, accumulating evidence shows that many bacterial pathogens exploit host ubiquitin systems for their own benefit. In this Review, we highlight the ways in which human bacterial pathogens target ubiquitylation to subvert and manipulate host defence systems, with a focus on the role of molecular mimicry and secreted bacterial effector proteins. These strategies enable bacterial pathogens to maximize effector function and obtain nutrients, thereby promoting bacterial proliferation. PMID:24801936

Ashida, Hiroshi; Kim, Minsoo; Sasakawa, Chihiro

2014-06-01

127

Intestinal Epithelial CD98 Directly Modulates the Innate Host Response to Enteric Bacterial Pathogens  

PubMed Central

CD98 is a type II transmembrane glycoprotein whose expression increases in intestinal epithelial cells (IECs) during intestinal inflammation. Enteropathogenic Escherichia coli (EPEC) is a food-borne human pathogen that attaches to IECs and injects effector proteins directly into the host cells, thus provoking an inflammatory response. In the present study, we investigated CD98 and EPEC interactions in vitro and ex vivo and examined FVB wild-type (WT) and villin-CD98 transgenic mice overexpressing human CD98 in IECs (hCD98 Tg mice) and infected with Citrobacter rodentium as an in vivo model. In vivo studies indicated that CD98 overexpression, localized to the apical domain of colonic cells, increased the attachment of C. rodentium in mouse colons and resulted in increased expression of proinflammatory markers and decreased expression of anti-inflammatory markers. The proliferative markers Ki-67 and cyclin D1 were significantly increased in the colonic tissue of C. rodentium-infected hCD98 Tg mice compared to that of WT mice. Ex vivo studies correlate with the in vivo data. Small interfering RNA (siRNA) studies with Caco2-BBE cells showed a decrease in adherence of EPEC to Caco2 cells in which CD98 expression was knocked down. In vitro surface plasmon resonance (SPR) experiments showed direct binding between recombinant hCD98 and EPEC/C. rodentium proteins. We also demonstrated that the partial extracellular loop of hCD98 was sufficient for direct binding to EPEC/C. rodentium. These findings demonstrate the importance of the extracellular loop of CD98 in the innate host defense response to intestinal infection by attaching and effacing (A/E) pathogens.

Laroui, Hamed; Liu, Hongchun; Viennois, Emilie; Ayyadurai, Saravanan; Xiao, Bo; Ingersoll, Sarah A.; Kalman, Daniel; Merlin, Didier

2013-01-01

128

Genome sequence of Victivallis vadensis ATCC BAA-548, an anaerobic bacterium from the phylum Lentisphaerae, isolated from the human gastro-intestinal tract  

SciTech Connect

Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastro-intestinal tract.

Van Passel, Mark W.J. [Wageningen University and Research Centre, The Netherlands; Kant, Ravi [University of Helsinki; Palva, Airi [University of Helsinki; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Davenport, Karen W. [Los Alamos National Laboratory (LANL); Sims, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Larimer, Frank W [ORNL; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Ovchinnikova, Galina [U.S. Department of Energy, Joint Genome Institute; Richardson, Paul [U.S. Department of Energy, Joint Genome Institute; De Vos, Willem M. [Wageningen University and Research Centre, The Netherlands; Smidt, Hauke [Wageningen University and Research Centre, The Netherlands; Zoetendal, Erwin G. [Wageningen University and Research Centre, The Netherlands

2011-01-01

129

Nod1 and Nod2 signaling does not alter the composition of intestinal bacterial communities at homeostasis  

PubMed Central

Patients with inflammatory bowel diseases (IBD) harbour intestinal bacterial communities with altered composition compared with healthy counterparts; however, it is unknown whether changes in the microbiota are associated with genetic susceptibility of individuals for developing disease or instead reflect other changes in the intestinal environment related to the disease itself. Since deficiencies in the innate immune receptors Nod1 and Nod2 are linked to IBD, we tested the hypothesis that Nod-signaling alters intestinal immune profiles and subsequently alters bacterial community structure. We used qPCR to analyze expression patterns of selected immune mediators in the ileum and cecum of Nod-deficient mice compared with their Nod-sufficient littermates and assessed the relative abundance of major bacterial groups sampled from the ileum, cecum and colon. The Nod1-deficient ileum exhibited significantly lower expression of Nod2, Muc2, ?- and ?-defensins and keratinocyte-derived chemokine (KC), suggesting a weakened epithelial barrier compared with WT littermates; however, there were no significant differences in the relative abundance of targeted bacterial groups, indicating that Nod1-associated immune differences alone do not promote dysbiosis. Furthermore, Nod2-deficient mice did not display any changes in the expression of immune markers or bacterial communities. Shifts in bacterial communities that were observed in this study correlated with housing conditions and were independent of genotype. These findings emphasize the importance of using F2 littermate controls to minimize environmental sources of variation in microbial analyses, to establish baseline conditions for host-microbe homeostasis in Nod-deficient mice and to strengthen models for testing factors contributing to microbial dysbiosis associated with IBD.

Robertson, Susan J.; Zhou, Jun Yu; Geddes, Kaoru; Rubino, Stephen J.; Cho, Joon Ho; Girardin, Stephen E.; Philpott, Dana J.

2013-01-01

130

Development of the Human Infant Intestinal Microbiota  

PubMed Central

Almost immediately after a human being is born, so too is a new microbial ecosystem, one that resides in that person's gastrointestinal tract. Although it is a universal and integral part of human biology, the temporal progression of this process, the sources of the microbes that make up the ecosystem, how and why it varies from one infant to another, and how the composition of this ecosystem influences human physiology, development, and disease are still poorly understood. As a step toward systematically investigating these questions, we designed a microarray to detect and quantitate the small subunit ribosomal RNA (SSU rRNA) gene sequences of most currently recognized species and taxonomic groups of bacteria. We used this microarray, along with sequencing of cloned libraries of PCR-amplified SSU rDNA, to profile the microbial communities in an average of 26 stool samples each from 14 healthy, full-term human infants, including a pair of dizygotic twins, beginning with the first stool after birth and continuing at defined intervals throughout the first year of life. To investigate possible origins of the infant microbiota, we also profiled vaginal and milk samples from most of the mothers, and stool samples from all of the mothers, most of the fathers, and two siblings. The composition and temporal patterns of the microbial communities varied widely from baby to baby. Despite considerable temporal variation, the distinct features of each baby's microbial community were recognizable for intervals of weeks to months. The strikingly parallel temporal patterns of the twins suggested that incidental environmental exposures play a major role in determining the distinctive characteristics of the microbial community in each baby. By the end of the first year of life, the idiosyncratic microbial ecosystems in each baby, although still distinct, had converged toward a profile characteristic of the adult gastrointestinal tract.

Palmer, Chana; Bik, Elisabeth M; DiGiulio, Daniel B; Relman, David A; Brown, Patrick O

2007-01-01

131

Identification of Bacterial Isolates Obtained from Intestinal Contents Associated with 12,000-Year-Old Mastodon Remains  

PubMed Central

Mastodon (Mammut americanum) remains unearthed during excavation of ancient sediments usually consist only of skeletal material, due to postmortem decomposition of soft tissues by microorganisms. Two recent excavations of skeletal remains in anoxic sediments in Ohio and Michigan, however, have uncovered organic masses which appear to be remnants of the small and large intestines, respectively. Macrobotanical examinations of the composition of these masses revealed assemblages of plant material radiocarbon dated to approximately 11,500 years before the present and thought to be incompletely digested food remains from this extinct mammal. We attempted to cultivate and identify bacteria from the intestinal contents, bone-associated sediments, and sediments not in proximity to the remains using a variety of general and selective media. In all, 295 isolates were cultivated, and 38 individual taxa were identified by fatty acid-methyl ester (FAME) profiles and biochemical characteristics (API-20E). The taxonomic positions of selected enteric and obligately anaerobic bacteria were confirmed by 16S ribosomal DNA (rDNA) sequencing. Results indicate that the intestinal and bone-associated samples contained the greatest diversity of bacterial taxa and that members of the family Enterobacteriaceae represented 41% of all isolates and were predominant in the intestinal masses and sediments in proximity to the skeleton but were uncommon in the background sediments. Enterobacter cloacae was the most commonly identified isolate, and partial rDNA sequencing revealed that Rahnella aquatilis was the correct identity of strains suggested by FAME profiles to be Yersinia enterocolitica. No Bacteroides spp. or expected intestinal anaerobes were recovered. The only obligate anaerobes recovered were clostridia, and these were not recovered from the small intestinal masses. Microbiological evidence from this study supports other, macrobotanical data indicating the intestinal origin of these masses. Whether these organisms are direct descendants of the original intestinal microbiota, however, cannot be established.

Rhodes, A. N.; Urbance, J. W.; Youga, H.; Corlew-Newman, H.; Reddy, C. A.; Klug, M. J.; Tiedje, J. M.; Fisher, D. C.

1998-01-01

132

Loss of Sirt1 Function Improves Intestinal Anti-Bacterial Defense and Protects from Colitis-Induced Colorectal Cancer  

PubMed Central

Dysfunction of Paneth and goblet cells in the intestine contributes to inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC). Here, we report a role for the NAD+-dependent histone deacetylase SIRT1 in the control of anti-bacterial defense. Mice with an intestinal specific Sirt1 deficiency (Sirt1int?/?) have more Paneth and goblet cells with a consequent rearrangement of the gut microbiota. From a mechanistic point of view, the effects on mouse intestinal cell maturation are mediated by SIRT1-dependent changes in the acetylation status of SPDEF, a master regulator of Paneth and goblet cells. Our results suggest that targeting SIRT1 may be of interest in the management of IBD and CAC.

Lo Sasso, Giuseppe; Ryu, Dongryeol; Mouchiroud, Laurent; Fernando, Samodha C.; Anderson, Christopher L.; Katsyuba, Elena; Piersigilli, Alessandra; Hottiger, Michael O.; Schoonjans, Kristina; Auwerx, Johan

2014-01-01

133

Drosophila melanogaster as a model for human intestinal infection and pathology  

PubMed Central

Recent findings concerning Drosophila melanogaster intestinal pathology suggest that this model is well suited for the study of intestinal stem cell physiology during aging, stress and infection. Despite the physiological divergence between vertebrates and insects, the modeling of human intestinal diseases is possible in Drosophila because of the high degree of conservation between Drosophila and mammals with respect to the signaling pathways that control intestinal development, regeneration and disease. Furthermore, the genetic amenability of Drosophila makes it an advantageous model species. The well-studied intestinal stem cell lineage, as well as the tools available for its manipulation in vivo, provide a promising framework that can be used to elucidate many aspects of human intestinal pathology. In this Perspective, we discuss recent advances in the study of Drosophila intestinal infection and pathology, and briefly review the parallels and differences between human and Drosophila intestinal regeneration and disease.

Apidianakis, Yiorgos; Rahme, Laurence G.

2011-01-01

134

Irritable bowel syndrome and small intestinal bacterial overgrowth: meaningful association or unnecessary hype.  

PubMed

Irritable bowel syndrome (IBS) is a common condition characterized by abdominal pain or discomfort, bloating, and altered stool form and passage. Small intestinal bacterial overgrowth (SIBO) is a condition in which there is overgrowth of bacteria in small bowel in excess of 10? colony forming units per milliliter on culture of the upper gut aspirate. Frequency of SIBO varied from 4%-78% among patients with IBS and from 1%-40% among controls. Higher frequency in some studies might be due to fallacious criteria [post-lactulose breath-hydrogen rise 20 PPM above basal within 90 min (early-peak)]. Glucose hydrogen breath test (GHBT) has a low sensitivity to diagnose SIBO. Hence, studies based on GHBT might have under-estimated frequency of SIBO. Therefore, it is important to analyze these studies carefully to evaluate whether the reported association between IBS and SIBO is over or under-projected. This review evaluates studies on association between SIBO and IBS, discordance between different studies, their strength and weakness including methodological issues and evidence on therapeutic manipulation of gut flora on symptoms of IBS. PMID:24627585

Ghoshal, Uday C; Srivastava, Deepakshi

2014-03-14

135

Small intestine bacterial overgrowth and irritable bowel syndrome-related symptoms: Experience with Rifaximin  

PubMed Central

AIM: To estimate the prevalence of small intestinal bacterial overgrowth (SIBO) in our geographical area (Western Sicily, Italy) by means of an observational study, and to gather information on the use of locally active, non-absorbable antibiotics for treatment of SIBO. METHODS: Our survey included 115 patients fulfilling the Rome II criteria for diagnosis of irritable bowel syndrome (IBS); a total of 97 patients accepted to perform a breath test with lactulose (BTLact), and those who had a positive test, received Rifaximin (Normix®, Alfa Wassermann) 1200 mg/d for 7 d; 3 wk after the end of treatment, the BTLact was repeated. RESULTS: Based on the BTLact results, SIBO was present in about 56% of IBS patients, and it was responsible for some IBS-related symptoms, such as abdominal bloating and discomfort, and diarrhoea. 1-wk treatment with Rifaximin turned the BTLact to negative in about 50% of patients and significantly reduced the symptoms, especially in those patients with an alternated constipation/diarrhoea-variant IBS. CONCLUSION: SIBO should be always suspected in patients with IBS, and a differential diagnosis is done by means of a “breath test”. Rifaximin may represent a valid approach to the treatment of SIBO.

Peralta, Sergio; Cottone, Claudia; Doveri, Tiziana; Almasio, Piero Luigi; Craxi, Antonio

2009-01-01

136

The involvement of Aeromonas salmonicida virulence factors in bacterial translocation across the rainbow trout, Oncorhynchus mykiss (Walbaum), intestine.  

PubMed

The pathogenic bacterium Aeromonas salmonicida is the causative agent of furunculosis, a lethal disease in salmonids. The mode of lateral transmission has not been conclusively defined, but A. salmonicida is able to translocate across the intestinal epithelium of salmonids, making the intestinal route a probable candidate. This study investigated some of the virulence mechanisms used by the bacteria to promote translocation. Intestinal segments were placed in modified Ussing chambers to investigate epithelial functions during exposure to bacterial factors. The factors were: extracellular products (ECP), lipopolysaccharide (LPS) or live or heat-inactivated A. salmonicida. Fluorescein isothiocynate (FITC)-labelling enabled detection of translocated bacteria by fluorometry. Live A. salmonicida translocated to a greater degree than heat-inactivated bacteria, suggesting that the bacteria utilize a heat sensitive surface-bound virulence factor which promotes translocation. The epithelium was negatively affected by ECP, manifested as decreased net ion transport, indicating a disturbance in ion channels or cell metabolism. LPS did not affect the epithelium in vitro when administered on the luminal side of the intestinal segment, but significantly increased epithelial translocation of fluorescent bacterial-sized microspheres when administered on the serosal side. This is suggested to be caused by increased transcellular transport, as the paracellular permeability was unaffected indicating maintained epithelial integrity. PMID:18234022

Jutfelt, F; Sundh, H; Glette, J; Mellander, L; Thrandur Björnsson, B; Sundell, K

2008-02-01

137

Ras gene activation in human small intestinal tumors.  

PubMed

Expression of the ras oncoprotein in thirteen human small intestinal tumors was investigated employing an immunohistochemical technique. The level of ras p21 was analysed using the monoclonal antibody Y13-259 and the biotin-streptavidin-peroxidace-DAB technique. Nine out of thirteen tumors including one hyperplastic - metaplastic polyp, one adenomatous and papillary polyp of the duodenum, one adenomatous polyp, one leiomyoma, one carcinoid, one lymphoma, one angiosarcoma of the jejunum, one leiomyosarcoma and one metastatic adenocarcinoma of the colon, were found to ''press the ras p21 oncoprotein at elevated levels, as compared to adjacent normal tissue. Whereas in one Brunner's gland adenoma of the duodenum, one neurilemoma, one adenocarcinoma of the small intestine and one metastatic adenocarcinoma of the colon expression of ras p21 was not elevated. The detection of H-ras mutations in codon 12 and K-ras mutations in codons 12 and 13 was also examined using the polymerase chain reaction technique. Four out of the thirteen small intestinal tumors examined possessed mutations of the H-ras gene in codon 12. These included the following, tumors: one Brunner's gland adenoma of the duodenum, one lymphoma, one leiomyo-sarcoma and one metastatic adenocarcinoma of the colon. This is the first demonstration of ras mutations in small intestinal tumors. None of the tumors had mutations in K-ras codons 12 or 13 (Gly-->Asp) It is suggested that the ras p21 oncoprotein may be involved in the pathogenesis and H-ras mutations and be a molecular genetic marker in small intestinal tumors. PMID:21573584

Spandidos, D; Liloglou, T; Arvanitis, D; Gourtsoyiannis, N

1993-04-01

138

V gamma (I) expression in human intestinal lymphocytes is restricted.  

PubMed

The majority of human intestinal intraepithelial lymphocytes (HIELS) express CD8+, and the T cell Receptor (TCR) alpha beta. A minority of HIELS utilize TCR gamma delta chains. V delta 1 is established as the TCR-delta expressed by most TCR gamma delta HIELS. Since V delta 1 is the dominant intestinal TCR and V gamma (I) family is preferentially used in forming a heterodimer, this study was conducted to characterize individual V gamma (I) utilization in HIELS. Intestinal lymphocytes were isolated from four samples of colonic epithelium obtained from patients undergoing colon resection or endoscopy. RNA was isolated and cDNA synthesized. PCR amplification was performed with consensus J gamma and V gamma primers in these regions. PCR products were cloned and sequenced. All samples had V gamma 4 transcripts, a majority V gamma 3 whereas V gamma 2 and V gamma 8 were less frequent. No V gamma 2 transcripts had any predicted TCR protein products. Similarly, very few potentially productive V gamma 3 transcripts were found. In contrast, almost all V gamma 4 transcripts were found to be in-frame and the only V gamma 8 transcript was in-frame. The CDR3 region of the gamma transcripts were small compared to published intestinal TCR delta recombinations. All CDR3 regions contained at least one charged amino acid. The limited number of functional transcripts adds evidence to the oligoclonality of intestinal TCRs expressing the TCR V gamma (I) family. The short CDR3 regions support the concept of limited antigen recognition by this lymphocyte population. PMID:8575839

Landau, S B; Aziz, W I; Woodcock-Mitchell, J; Melamede, R

1995-11-01

139

Long-term treatment with cisapride and antibiotics in liver cirrhosis: effect on small intestinal motility, bacterial overgrowth, and liver function  

Microsoft Academic Search

OBJECTIVES:Altered small-bowel motility, lengthening of the orocecal transit time, and small-intestinal bacterial overgrowth have been described in patients with liver cirrhosis. These changes might be related to the progressive course and poor prognosis of the disease. We investigated the effect of a long-term treatment with cisapride and an antibiotic regimen on small-intestinal motor activity, orocecal transit time, bacterial overgrowth, and

Ana Maria Madrid; Carmen Hurtado; Mauricio Venegas; Francisco Cumsille; Carlos Defilippi

2001-01-01

140

Parenteral Antibiotics and Selective Intestinal Decontamination Do Not Prevent Enteric Bacterial Overgrowth or Translocation Observed in a Swine Model of Small Bowel Transplantation  

Microsoft Academic Search

Alterations in the luminal microflora and increased intestinal translocation have been reported to occur following experimental and clinical small bowel transplantation (SBT). Selective intestinal decontamination (SID) has been used to prevent luminal overgrowth and bacterial translocation. Despite the wide use of SID in clinical SBT, there are no data supporting its usefulness in this situation. Thus, the aim of this

Roberto Biffi; Gaetano Privitera; Caterina Matinato; Simonetta Pozzi; Lorenzo Marzona; Paolo De Rai; Bruno Andreoni; Giorgio Tiberio; Ermenegildo Frezza; David H. Van Thiel

1995-01-01

141

Evidence of Bacterial Biofilms in Human Chronic Sinusitis  

Microsoft Academic Search

The purpose of this study was to evaluate whether bacterial biofilms exist on the sinus mucosa surfaces of human subjects with recalcitrant chronic sinusitis. Scanning electron microscopy was used to evaluate patients with continued symptoms of chronic sinusitis despite prior appropriate medical and surgical management. Morphologic structures that confirm the presence of bacterial biofilms were identified on the sinus mucosa

Jonathan Cryer; Ioana Schipor; Joel R. Perloff; James N. Palmer

2004-01-01

142

Transport of thiamine in human intestine: mechanism and regulation in intestinal epithelial cell model Caco-2.  

PubMed

The present study examined the intestinal uptake of thiamine (vitamin B(1)) using the human-derived intestinal epithelial cells Caco-2 as an in vitro model system. Thiamine uptake was found to be 1) temperature and energy dependent and occurred with minimal metabolic alteration; 2) pH sensitive; 3) Na(+) independent; 4) saturable as a function of concentration with an apparent Michaelis-Menten constant of 3.18 +/- 0.56 microM and maximal velocity of 13.37 +/- 0.94 pmol. mg protein(-1). 3 min(-1); 5) inhibited by the thiamine structural analogs amprolium and oxythiamine, but not by unrelated organic cations tetraethylammonium, N-methylnicotinamide, and choline; and 6) inhibited in a competitive manner by amiloride with an inhibition constant of 0.2 mM. The role of specific protein kinase-mediated pathways in the regulation of thiamine uptake by Caco-2 cells was also examined using specific modulators of these pathways. The results showed possible involvement of a Ca(2+)/calmodulin (CaM)-mediated pathway in the regulation of thiamine uptake. No role for protein kinase C- and protein tyrosine kinase-mediated pathways in the regulation of thiamine uptake was evident. These results demonstrate the involvement of a carrier-mediated system for thiamine uptake by Caco-2 intestinal epithelial cells. This system is Na(+) independent and is different from the transport systems of organic cations. Furthermore, a CaM-mediated pathway appears to play a role in regulating thiamine uptake in these cells. PMID:10516094

Said, H M; Ortiz, A; Kumar, C K; Chatterjee, N; Dudeja, P K; Rubin, S

1999-10-01

143

OPTIMIZING THE ANALYSIS OF HUMAN INTESTINAL MICROBIOTA WITH PHYLOGENETIC MICROARRAY  

PubMed Central

Phylogenetic microarrays present an attractive strategy to high-throughput interrogation of complex microbial communities. In this work we present several approaches to optimize the analysis of intestinal microbiota with the recently developed Microbiota Array. First, we determined how 16S rDNA-specific PCR amplification influenced bacterial detection and the consistency of measured abundance values. Bacterial detection improved with an increase in the number of PCR amplification cycles, but 25 cycles were sufficient to achieve the maximum possible detection. A PCR-caused deviation in the measured abundance values was also observed. We also developed two mathematical algorithms aimed to account for a predicted cross-hybridization of 16S rDNA fragments among different species, and to adjust the measured hybridization signal based on the number of 16S rRNA gene copies per species genome. The 16S rRNA gene copy adjustment indicated that the presence of members of class Clostridia might be over-estimated in some 16S rDNA-based studies. Finally, we show that the examination of total community RNA with phylogenetic microarray can provide estimates of the relative metabolic activity of individual community members. Complementary profiling of genomic DNA and total RNA isolated from the same sample presents an opportunity to assess population structure and activity in the same microbial community.

Rigsbee, Laura; Agans, Richard; Foy, Brent; Paliy, Oleg

2010-01-01

144

A comparative analysis of the intestinal metagenomes present in guinea pigs (Cavia porcellus) and humans (Homo sapiens)  

PubMed Central

Background Guinea pig (Cavia porcellus) is an important model for human intestinal research. We have characterized the faecal microbiota of 60 guinea pigs using Illumina shotgun metagenomics, and used this data to compile a gene catalogue of its prevalent microbiota. Subsequently, we compared the guinea pig microbiome to existing human gut metagenome data from the MetaHIT project. Results We found that the bacterial richness obtained for human samples was lower than for guinea pig samples. The intestinal microbiotas of both species were dominated by the two phyla Bacteroidetes and Firmicutes, but at genus level, the majority of identified genera (320 of 376) were differently abundant in the two hosts. For example, the guinea pig contained considerably more of the mucin-degrading Akkermansia, as well as of the methanogenic archaea Methanobrevibacter than found in humans. Most microbiome functional categories were less abundant in guinea pigs than in humans. Exceptions included functional categories possibly reflecting dehydration/rehydration stress in the guinea pig intestine. Finally, we showed that microbiological databases have serious anthropocentric biases, which impacts model organism research. Conclusions The results lay the foundation for future gastrointestinal research applying guinea pigs as models for humans.

2012-01-01

145

Inhibition of Intestinal Bacterial Translocation with Rifaximin Modulates Lamina propria Monocytic Cells Reactivity and Protects against Inflammation in a Rodent Model of Colitis  

Microsoft Academic Search

Background: A modification of the intestinal flora and an increased bacterial translocation is a common finding in patients with inflammatory bowel disease as well as in animal model of colitis. Rifaximin, a non-absorbable derivative of rifamycin, is an effective antibiotic that acts by inhibiting bacterial ribonucleic acid synthesis. Aims: In the present study, we investigated the effect of the administration

Stefano Fiorucci; Eleonora Distrutti; Andrea Mencarelli; Miriam Barbanti; Ernesto Palazzini; Antonio Morelli

2002-01-01

146

Adenoviruses in Lymphocytes of the Human Gastro-Intestinal Tract  

PubMed Central

Objective Persistent adenoviral shedding in stools is known to occur past convalescence following acute adenoviral infections. We wished to establish the frequency with which adenoviruses may colonize the gut in normal human subjects. Methods The presence of adenoviral DNA in intestinal specimens obtained at surgery or autopsy was tested using a nested PCR method. The amplified adenoviral DNA sequences were compared to each other and to known adenoviral species. Lamina propria lymphocytes (LPLs) were isolated from the specimens and the adenoviral copy numbers in the CD4+ and CD8+ fractions were determined by quantitative PCR. Adenoviral gene expression was tested by amplification of adenoviral mRNA. Results Intestinal tissue from 21 of 58 donors and LPLs from 21 of 24 donors were positive for the presence of adenoviral DNA. The majority of the sequences could be assigned to adenoviral species E, although species B and C sequences were also common. Multiple sequences were often present in the same sample. Forty-one non-identical sequences were identified from 39 different tissue donors. Quantitative PCR for adenoviral DNA in CD4+ and CD8+ fractions of LPLs showed adenoviral DNA to be present in both cell types and ranged from a few hundred to several million copies per million cells on average. Active adenoviral gene expression as evidenced by the presence of adenoviral messenger RNA in intestinal lymphocytes was demonstrated in 9 of the 11 donors tested. Conclusion Adenoviral DNA is highly prevalent in lymphocytes from the gastro-intestinal tract indicating that adenoviruses may be part of the normal gut flora.

Roy, Soumitra; Calcedo, Roberto; Medina-Jaszek, Angelica; Keough, Martin; Peng, Hui; Wilson, James M.

2011-01-01

147

Mechanisms that control bacterial populations in continuous-flow culture models of mouse large intestinal flora.  

PubMed

A previous study had established that anaerobic continuous-flow (CF) cultures of conventional mouse cecal flora were able to maintain the in vivo ecological balance among the indigenous bacterial species tested. This paper describes experiments designed to determine the mechanisms which control the population sizes of these species in such CF cultures. One strain each of Escherichia coli, Fusobacterium sp., and Eubacterium sp. were studied. Growth of these strains in filtrates of CF cultures was considerably more rapid than in the CF cultures themselves, indicating that the inhibitory activity had been lost in the process of filtration. Growth rates to match those in CF cultures could be obtained, however, by restoring the original levels of H(2)S in the culture filtrates. The inhibitory effect of H(2)S in filtrates and in dialysates of CF cultures could be abolished by adding glucose or pyruvate, but not formate or lactate. The fatty acids present in CF cultures matched those in the cecum of conventional mice in both quality and concentration. These acids could not account for the slow rates of growth of the tested strains in CF cultures, but they did cause a marked increase in the initial lag phase of E. coli growth. The results obtained are compatible with the hypothesis that the populations of most indigenous intestinal bacteria are controlled by one or a few nutritional substrates which a given strain can utilize most efficiently in the presence of H(2)S and at the prevailing conditions of pH and anaerobiosis. This hypothesis consequently implies that the populations of enterobacteria, such as the E. coli strain tested, and those of the predominant anaerobes are controlled by analogous mechanisms. PMID:6339388

Freter, R; Brickner, H; Botney, M; Cleven, D; Aranki, A

1983-02-01

148

[Progress in the knowledge of the intestinal human microbiota].  

PubMed

New sequencing technologies together with the development of bio-informatics allow a description of the full spectrum of the microbial communities that inhabit the human intestinal tract, as well as their functional contributions to host health. Most community members belong to the domain Bacteria, but Archaea, Eukaryotes (yeasts and protists), and Viruses are also present. Only 7 to 9 of the 55 known divisions or phyla of the domain Bacteria are detected in faecal or mucosal samples from the human gut. Most taxa belong to just two divisions: Bacteroidetes and Firmicutes, and the other divisions that have been consistently found are Proteobacteria, Actinobacteria, Fusobacteria, and Verrucomicrobia. Bacteroides, Faecalibacterium and Bifidobacterium are the most abundant genera but their relative proportion is highly variable across individuals. Full metagenomic analysis has identified more than 5 million non-redundant microbial genes encoding up to 20,000 biological functions related with life in the intestinal habitat. The overall structure of predominant genera in the human gut can be assigned into three robust clusters, which are known as "enterotypes". Each of the three enterotypes is identifiable by the levels of one of three genera: Bacteroides (enterotype 1), Prevotella (enterotype 2) and Ruminococcus (enterotype 3). This suggests that microbiota variations across individuals are stratified, not continuous. Next steps include the identification of changes that may play a role in certain disease states. A better knowledge of the contributions of microbial symbionts to host health will help in the design of interventions to improve symbiosis and combat disease. PMID:23848071

Robles-Alonso, Virginia; Guarner, Francisco

2013-01-01

149

Human Intestinal M Cells Display the Sialyl Lewis A Antigen  

PubMed Central

The biochemical features that distinguish human M cells from other intestinal epithelial cell types are important for understanding microbial pathogenesis and for targeting vaccines to the mucosal immune system. We applied a large panel of carbohydrate-specific monoclonal antibodies and lectins to Peyer’s patch and cecum biopsy specimens from three normal individuals and a patient with inflammatory bowel disease. The results show that human M-cell glycosylation patterns are distinct from those of other species examined and that human M cells preferentially display the sialyl Lewis A antigen. This carbohydrate epitope is also present in a small subpopulation of enterocytes in the follicle-associated epithelium and in goblet cell mucins.

Giannasca, Paul J.; Giannasca, Karen T.; Leichtner, Alan M.; Neutra, Marian R.

1999-01-01

150

Hand bacterial communities vary across two different human populations.  

PubMed

This study utilized pyrosequencing-based phylogenetic library results to assess bacterial communities on the hands of women in Tanzania and compared these communities with bacteria assemblages on the hands of US women. Bacterial population profiles and phylogenetically based ordinate analysis demonstrated that the bacterial communities on hands were more similar for selected populations within a country than between the two countries considered. Organisms that have commonly been identified in prior human skin microbiome studies, including members of the Propionibacteriaceae, Staphylococcaceae and Streptococceacea families, were highly abundant on US hands and drove the clustering of US hand microbial communities into a distinct group. The most abundant bacterial taxa on Tanzanian hands were the soil-associated Rhodobacteraceae and Nocardioidaceae. These results help to expand human microbiome results beyond US and European populations, and the identification and abundance of soil-associated bacteria on Tanzanian hands demonstrated the important role of the environment in shaping the microbial communities on human hands. PMID:24817404

Hospodsky, Denina; Pickering, Amy J; Julian, Timothy R; Miller, Dana; Gorthala, Sisira; Boehm, Alexandria B; Peccia, Jordan

2014-06-01

151

Human intestinal epithelial cells produce proinflammatory cytokines in response to infection in a SCID mouse-human intestinal xenograft model of amebiasis.  

PubMed Central

The protozoan parasite Entamoeba histolytica causes amebic dysentery and amebic liver abscess, diseases associated with significant morbidity and mortality worldwide. E. histolytica infection appears to involve the initial attachment of amebic trophozoites to intestinal epithelial cells, followed by lysis of these cells and subsequent invasion into the submucosa. A recent in vitro study (L. Eckmann, S. L. Reed, J. R. Smith, and M. F. Kagnoff, J. Clin. Invest. 96:1269-1279, 1995) demonstrated that incubation of E. histolytica trophozoites with epithelial cell lines results in epithelial cell production of inflammatory cytokines, including interleukin-1 (IL-1) and IL-8, suggesting that intestinal epithelial cell production of cytokines might play a role in the inflammatory response and tissue damage seen in intestinal amebiasis. To determine whether intestinal epithelial cell production of IL-1 and IL-8 occurs in response to E. histolytica infection in vivo and as an approach to studying the specific interactions between amebic trophozoites and human intestine, we used a SCID mouse-human intestinal xenograft (SCID-HU-INT) model of disease, where human intestinal xenografts were infected with virulent E. histolytica trophozoites. Infection of xenografts with E. histolytica trophozoites resulted in extensive tissue damage, which was associated with the development of an early inflammatory response composed primarily of neutrophils. Using oligonucleotide primers that specifically amplify human IL-1beta and IL-8, we could demonstrate by reverse transcription PCR that mRNA for both IL-1beta and IL-8 is produced by human intestinal xenografts in response to amebic infection. The increase in human intestinal IL-1beta and IL-8 in response to invasive amebiasis was confirmed by enzyme-linked immunosorbent assays specific for human IL-1beta and IL-8. Using immunohistochemistry, we confirmed that human intestinal epithelial cells were the source of IL-8 in infected xenografts and established that IL-8 production can occur at sites distal to areas of intestinal mucosal damage. These results demonstrate that human intestinal epithelial cells can produce inflammatory cytokines in response to infection in vivo and establish the SCID-HU-INT model as a system for studying the interactions between E. histolytica and human intestine.

Seydel, K B; Li, E; Swanson, P E; Stanley, S L

1997-01-01

152

The colonization of a simulator of the human intestinal microbial ecosystem by a probiotic strain fed on a fermented oat bran product: effects on the gastrointestinal microbiota  

Microsoft Academic Search

The effects of Lactobacillus-GG-fermented oat bran product on the microbiota and its metabolic activity in the human gut were investigated, using a simulator\\u000a of the human intestinal microbial ecosystem (SHIME), by analysing the bacterial population, short-chain fatty acids and gas\\u000a production. In addition, the effects of fermented oat bran supernatant and supernatant samples from reactors 4, 5 and 6 (large

P. Kontula; J. Jaskari; L. Nollet; I. De Smet; A. von Wright; K. Poutanen; T. Mattila-Sandholm

1998-01-01

153

Use of stable isotopes to measure the metabolic activity of the human intestinal microbiota.  

PubMed

The human intestinal microbiota is a complex biological system comprising a vast repertoire of microbes with considerable metabolic activity relevant to both bacterial growth and host health. Greater strides have been made in the analysis of microbial diversity than in the measurement of functional activity, particularly in vivo. Stable isotope probing offers a new approach by coupling measurements of metabolic activity with microbial identification. Using a low-enrichment labeling strategy in vitro, this study has identified metabolically active bacterial groups via magnetic-bead capture methodology and stable isotope ratio analysis. Using five probes (EUB338, Bac303, Bif164, EREC482, and Clep866), changes in the activities of key intestinal microbial groups were successfully measured by exploiting tracers of de novo RNA synthesis. Perturbation of the nutrient source with oligofructose generated changes in the activity of bifidobacteria as expected, but also in the Bacteroides-Prevotella group, the Eubacterium rectale-Clostridium coccoides group, and the Clostridium leptum subgroup. Changes in activity were also observed in response to the medium type. This study suggests that changes in the functional activity of the gut microbiota can be assessed using tracers of de novo nucleic acid synthesis combined with measurement of low isotopic enrichment in 16S rRNA. Such tracers potentially limit substrate bias because they are universally available to bacteria. This low-enrichment labeling approach does not depend on the commercial availability of specific labeled substrates and can be easily translated to in vivo probing experiments of the functional activity of the microbiota in the human gut. PMID:21948826

Reichardt, Nicole; Barclay, Andrew R; Weaver, Lawrence T; Morrison, Douglas J

2011-11-01

154

Induction of bacterial antigen-specific colitis by a simplified human microbiota consortium in gnotobiotic interleukin-10-/- mice.  

PubMed

We evaluated whether a simplified human microbiota consortium (SIHUMI) induces colitis in germfree (GF) 129S6/SvEv (129) and C57BL/6 (B6) interleukin-10-deficient (IL-10(-/-)) mice, determined mouse strain effects on colitis and the microbiota, examined the effects of inflammation on relative bacterial composition, and identified immunodominant bacterial species in "humanized" IL-10(-/-) mice. GF wild-type (WT) and IL-10(-/-) 129 and B6 mice were colonized with 7 human-derived inflammatory bowel disease (IBD)-related intestinal bacteria and maintained under gnotobiotic conditions. Quantification of bacteria in feces, ileal and colonic contents, and tissues was performed using 16S rRNA gene selective quantitative PCR. Colonic segments were scored histologically, and gamma interferon (IFN-?), IL-12p40, and IL-17 levels were measured in supernatants of unstimulated colonic tissue explants and of mesenteric lymph node (MLN) cells stimulated by lysates of individual or aggregate bacterial strains. Relative bacterial species abundances changed over time and differed between 129 and B6 mice, WT and IL-10(-/-) mice, luminal and mucosal samples, and ileal and colonic or fecal samples. SIHUMI induced colitis in all IL-10(-/-) mice, with more aggressive colitis and MLN cell activation in 129 mice. Escherichia coli LF82 and Ruminococcus gnavus lysates induced dominant effector ex vivo MLN TH1 and TH17 responses, although the bacterial mucosal concentrations were low. In summary, this study shows that a simplified human bacterial consortium induces colitis in ex-GF 129 and B6 IL-10(-/-) mice. Relative concentrations of individual SIHUMI species are determined by host genotype, the presence of inflammation, and anatomical location. A subset of IBD-relevant human enteric bacterial species preferentially stimulates bacterial antigen-specific TH1 and TH17 immune responses in this model, independent of luminal and mucosal bacterial concentrations. PMID:24643531

Eun, Chang Soo; Mishima, Yoshiyuki; Wohlgemuth, Steffen; Liu, Bo; Bower, Maureen; Carroll, Ian M; Sartor, R Balfour

2014-06-01

155

[Human intestinal parasitosis: role of Dientamoeba fragilis in human infections].  

PubMed

The Authors report prevalences of intestinal parasitosis among home children and adults during 2002-2004, as in O&P as in acute or prolonged diarrhoea, with particular attention to the role of Dientamoeba fragilis, because often undervalued. Among 3139 subjects, 116 cases of dientamoebiasis (3.7%) and 62 of giardiasis (2.0%) were observed; not typical pathogenic protozoa were reported in 71 cases (2.3%); helminths were identified only in 8 cases (0.5%). Particularly, inside O&P group D. fragilis prevailed in 5.2% of cases (7.8% in adults and 0.5% in children) and G. duodenalis in 2.7% (3.5% and 1.3% respectively); inside acute diarrhoeas D. fragilis prevailed in 1.6% (3.9% and 0.3%) and G. duodenalis in 0.6% (1.3% and 0. 1%); inside prolonged diarrhoeas D. fragilis prevailed in 3.5 % (2.6% and 5.4%) and G. duodenalis in 3.9% (5.8% in adults and never in children). D. fragilis was more often observed among adults (6.3% of all) than among children (0.6%), like G. duodenalis (3.1% versus 0.6%). So, 107 strains of D. fragilis (92.2%) and 53 strains of G. duodenalis (85.5%) were identified in adults. D. fragilis was more frequent among females (24/39 cases, 61.5%, in the last year) while G. duodenalis was more frequent in males (13/23 cases, 56.5%). The Authors conclude underlining the importance of a permanent stain, as Giemsa stain, for a good and complete diagnosis of protozoal intestinal infections, particularly for D. fragilis. PMID:17405510

Crotti, D; D'Annibale, M L

2007-01-01

156

Mucosal Immune Regulation in Intestinal Disease. The role of bacterial products, food components and drugs  

Microsoft Academic Search

The challenge of the mucosal gut associated immune system is to remain unresponsive to food products and commensal microbiota, while mounting an appropriate immune response towards pathogens. This implicates the necessity of tight immune regulation within the gut associated lymphoid tissue (GALT). Imbalance between tolerance and immunity (e.g. intestinal homeostasis) contributes to the pathogenesis of intestinal diseases like inflammatory bowel

M. Bol-Schoenmakers

2009-01-01

157

Bacterial expression of human kynurenine 3-monooxygenase: Solubility, activity, purification?  

PubMed Central

Kynurenine 3-monooxygenase (KMO) is an enzyme central to the kynurenine pathway of tryptophan metabolism. KMO has been implicated as a therapeutic target in several disease states, including Huntington’s disease. Recombinant human KMO protein production is challenging due to the presence of transmembrane domains, which localise KMO to the outer mitochondrial membrane and render KMO insoluble in many in vitro expression systems. Efficient bacterial expression of human KMO would accelerate drug development of KMO inhibitors but until now this has not been achieved. Here we report the first successful bacterial (Escherichia coli) expression of active FLAG™-tagged human KMO enzyme expressed in the soluble fraction and progress towards its purification.

Wilson, K.; Mole, D.J.; Binnie, M.; Homer, N.Z.M.; Zheng, X.; Yard, B.A.; Iredale, J.P.; Auer, M.; Webster, S.P.

2014-01-01

158

Bats as Reservoir Hosts of Human Bacterial Pathogen, Bartonella mayotimonensis  

PubMed Central

A plethora of pathogenic viruses colonize bats. However, bat bacterial flora and its zoonotic threat remain ill defined. In a study initially conducted as a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton’s bat in Finland, we unexpectedly detected DNA of several hemotrophic and ectoparasite-transmitted bacterial genera, including Bartonella. Bartonella spp. also were either detected or isolated from the peripheral blood of Daubenton's, northern, and whiskered bats and were detected in the ectoparasites of Daubenton's, northern, and Brandt's bats. The blood isolates belong to the Candidatus-status species B. mayotimonensis, a recently identified etiologic agent of endocarditis in humans, and a new Bartonella species (B. naantaliensis sp. nov.). Phylogenetic analysis of bat-colonizing Bartonella spp. throughout the world demonstrates a distinct B. mayotimonensis cluster in the Northern Hemisphere. The findings of this field study highlight bats as potent reservoirs of human bacterial pathogens.

Veikkolainen, Ville; Vesterinen, Eero J.; Lilley, Thomas M.

2014-01-01

159

Bats as Reservoir Hosts of Human Bacterial Pathogen, Bartonella mayotimonensis.  

PubMed

A plethora of pathogenic viruses colonize bats. However, bat bacterial flora and its zoonotic threat remain ill defined. In a study initially conducted as a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton's bat in Finland, we unexpectedly detected DNA of several hemotrophic and ectoparasite-transmitted bacterial genera, including Bartonella. Bartonella spp. also were either detected or isolated from the peripheral blood of Daubenton's, northern, and whiskered bats and were detected in the ectoparasites of Daubenton's, northern, and Brandt's bats. The blood isolates belong to the Candidatus-status species B. mayotimonensis, a recently identified etiologic agent of endocarditis in humans, and a new Bartonella species (B. naantaliensis sp. nov.). Phylogenetic analysis of bat-colonizing Bartonella spp. throughout the world demonstrates a distinct B. mayotimonensis cluster in the Northern Hemisphere. The findings of this field study highlight bats as potent reservoirs of human bacterial pathogens. PMID:24856523

Veikkolainen, Ville; Vesterinen, Eero J; Lilley, Thomas M; Pulliainen, Arto T

2014-06-01

160

Dysmotility and ppi use are independent risk factors for small intestinal bacterial and/or fungal overgrowth  

PubMed Central

Introduction Whether intestinal dysmotility and proton pump inhibitor (PPI) use either independently or together contributes to small intestinal bacterial overgrowth (SIBO), and/or small intestinal fungal overgrowth (SIFO) is not known. Aim Investigate the role of dysmotility and PPI use in patients with persistent gastrointestinal complaints. Methods Patients with unexplained gastrointestinal symptoms and negative endoscopy/radiology tests completed a validated symptom questionnaire and underwent 24-hour ambulatory antro-duodeno-jejunal manometry (ADJM). Simultaneously, duodenal aspirate was obtained for aerobic, anaerobic and fungal culture. Dysmotility was diagnosed by (> 2): absent phase III MMC, absent/diminished postprandial response, diminished amplitude of antral/intestinal phasic activity, impaired antro-duodenal coordination. Bacterial growth ?103 CFU/mL or fungal growth was considered evidence for SIBO/SIFO. PPI use was documented. Correlation of symptoms with presence of SIBO or SIFO were assessed. Results 150 subjects (M/F=47/103) were evaluated; 94/150 (63%) had overgrowth: 38/94 (40%) had SIBO, 24/94 (26%) had SIFO, and 32/94 (34%) had mixed SIBO/SIFO. SIBO was predominately due to Streptococcus, Enterococcus, Klebsiella, and E. coli. SIFO was due to Candida. 80/150 (53%) patients had dysmotility and 65/150 (43%) used PPI. PPI use (p=.0063) and Dysmotility (p=.0003) were independent significant risk factors (p<0.05) for overgrowth, but together did not pose additional risk. Symptom profiles were similar between those with or without SIBO/SIFO. Conclusions Dysmotility and PPI use were independent risk factors for SIBO or SIFO and were present in over 50% of subjects with unexplained gastrointestinal symptoms. Diagnosis of overgrowth requires testing because symptoms were poor predictors of overgrowth.

Jacobs, C; Coss Adame, E; Attaluri, A; Valestin, J; Rao, SSC

2013-01-01

161

Age-related human small intestine methylation: evidence for stem cell niches  

Microsoft Academic Search

BACKGROUND: The small intestine is constructed of many crypts and villi, and mouse studies suggest that each crypt contains multiple stem cells. Very little is known about human small intestines because mouse fate mapping strategies are impractical in humans. However, it is theoretically possible that stem cell histories are inherently written within their genomes. Genomes appear to record histories (as

Jung Yeon Kim; Kimberly D Siegmund; Simon Tavaré; Darryl Shibata

2005-01-01

162

The V~I T Cell Receptor Repertoire in Human Small Intestine and Colon  

Microsoft Academic Search

Summary VS1 bearing T ceils comprise the major population of 3'\\/8 T cells in the human intestinal tract. To gain insight into mechanisms involved in the generation of these cells and the diversity of their repertoire, we have characterized the junctional sequences of V81 T cell receptor transcripts in the human small intestine and colon. Mucosal biopsies obtained from defined

Yehuda Chowers; Wolfgang Holtmeier; Julia Harwood; Ewa Morzycka-Wroblewska; Martin F. Kagnoff

163

Contribution of the microflora to proteolysis in the human large intestine.  

PubMed

Protease activities in human ileal effluent were approximately 20-fold greater than in normal faeces. Comparative studies with faeces from a person who did not have a pancreas suggested that a substantial proportion of the proteolytic activity in normal faeces was of bacterial origin. Thimerosal, iodoacetate, EDTA and cysteine significantly inhibited proteolysis in faeces, but not in small intestinal contents, showing that cysteine and metalloproteases were produced by bacteria in the large gut. These results, together with results from studies using p-nitroanilide substrates, demonstrated that faecal proteolysis was both qualitatively and quantitatively different from that in the small intestine. Studies with pure cultures of proteolytic gut bacteria indicated that the cell-bound proteases of Bacteroides fragilis-type organisms were likely to contribute significantly towards proteolytic activity associated with the washed cell fraction and washed particulate fraction of faeces. Extracellular proteases were formed by Streptococcus faecalis ST6, Propionibacterium acnes P6, Clostridium perfringens C16, Cl. bifermentans C21 and Cl. sporogenes C25. Inhibition results suggested that these bacteria, and similar organisms, may be partly responsible for the extracellular proteolytic activity found in the cell-free supernatant fraction of faeces. PMID:3127369

Macfarlane, G T; Allison, C; Gibson, S A; Cummings, J H

1988-01-01

164

Human intestinal ischemia-reperfusion-induced inflammation characterized: experiences from a new translational model.  

PubMed

Human intestinal ischemia-reperfusion (IR) is a frequent phenomenon carrying high morbidity and mortality. Although intestinal IR-induced inflammation has been studied extensively in animal models, human intestinal IR induced inflammatory responses remain to be characterized. Using a newly developed human intestinal IR model, we show that human small intestinal ischemia results in massive leakage of intracellular components from ischemically damaged cells, as indicated by increased arteriovenous concentration differences of intestinal fatty acid binding protein and soluble cytokeratin 18. IR-induced intestinal barrier integrity loss resulted in free exposure of the gut basal membrane (collagen IV staining) to intraluminal contents, which was accompanied by increased arteriovenous concentration differences of endotoxin. Western blot for complement activation product C3c and immunohistochemistry for activated C3 revealed complement activation after IR. In addition, intestinal IR resulted in enhanced tissue mRNA expression of IL-6, IL-8, and TNF-alpha, which was accompanied by IL-6 and IL-8 release into the circulation. Expression of intercellular adhesion molecule-1 was markedly increased during reperfusion, facilitating influx of neutrophils into IR-damaged villus tips. In conclusion, this study for the first time shows the sequelae of human intestinal IR-induced inflammation, which is characterized by complement activation, production and release of cytokines into the circulation, endothelial activation, and neutrophil influx into IR-damaged tissue. PMID:20348235

Grootjans, Joep; Lenaerts, Kaatje; Derikx, Joep P M; Matthijsen, Robert A; de Bruïne, Adriaan P; van Bijnen, Annemarie A; van Dam, Ronald M; Dejong, Cornelis H C; Buurman, Wim A

2010-05-01

165

Long-term monitoring of the human intestinal microbiota composition.  

PubMed

The microbiota that colonizes the human intestinal tract is complex and its structure is specific for each of us. In this study we expand the knowledge about the stability of the subject-specific microbiota and show that this ecosystem is stable in short-term intervals (?10 years). The faecal microbiota composition of five unrelated and healthy subjects was analysed using a comprehensive and highly reproducible phylogenetic microarray, the HITChip. The results show that the use of antibiotics, application of specific dietary regimes and distant travelling have limited impact on the microbiota composition. Several anaerobic genera, including Bifidobacterium and a number of genera within the Bacteroidetes and the Firmicutes phylum, exhibit significantly higher similarity than the total microbiota. Although the gut microbiota contains subject-specific species, the presence of which is preserved throughout the years, their relative abundance changes considerably. Consequently, the recently proposed enterotype status appears to be a varying characteristic of the microbiota. Our data show that the intestinal microbiota contains a core community of permanent colonizers, and that environmentally introduced changes of the microbiota throughout adulthood are primarily affecting the abundance but not the presence of specific microbial species. PMID:23286720

Rajili?-Stojanovi?, Mirjana; Heilig, Hans G H J; Tims, Sebastian; Zoetendal, Erwin G; de Vos, Willem M

2012-10-15

166

NFATc1 Regulation of TRAIL Expression in Human Intestinal Cells  

PubMed Central

TNF-related apoptosis-inducing ligand (TRAIL; Apo2) has been shown to promote intestinal cell differentiation. Nuclear factor of activated T cells (NFAT) participates in the regulation of a variety of cellular processes, including differentiation. Here, we examined the role of NFAT in the regulation of TRAIL in human intestinal cells. Treatment with a combination of phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187 (Io) increased NFAT activation and TRAIL expression; pretreatment with the calcineurin inhibitor cyclosporine A (CsA), an antagonist of NFAT signaling, diminished NFAT activation and TRAIL induction. In addition, knockdown of NFATc1, NFATc2, NFATc3, and NFATc4 blocked PMA/Io increased TRAIL protein expression. Expression of NFATc1 activated TRAIL promoter activity and increased TRAIL mRNA and protein expression. Deletion of NFAT binding sites from the TRAIL promoter did not significantly abrogate NFATc1-increased TRAIL promoter activity, suggesting an indirect regulation of TRAIL expression by NFAT activation. Knockdown of NFATc1 increased Sp1 transcription factor binding to the TRAIL promoter and, importantly, inhibition of Sp1, by chemical inhibition or RNA interference, increased TRAIL expression. These studies identify a novel mechanism for TRAIL regulation by which activation of NFATc1 increases TRAIL expression through negative regulation of Sp1 binding to the TRAIL promoter.

Wang, Qingding; Zhou, Yuning; Weiss, Heidi L.; Chow, Chi-Wing; Evers, B. Mark

2011-01-01

167

Antibiotics conspicuously affect community profiles and richness, but not the density of bacterial cells associated with mucosa in the large and small intestines of mice.  

PubMed

The influence of three antibiotics (bacitracin, enrofloxacin, and neomycin sulfate) on the mucosa-associated enteric microbiota and the intestines of mice was examined. Antibiotics caused conspicuous enlargement of ceca and an increase in overall length of the intestine. However, there were no pathologic changes associated with increased cecal size or length of the intestine. Conspicuous reductions in the richness of mucosa-associated bacteria and changes to community profiles within the small (duodenum, proximal jejunum, middle jejunum, distal jejunum, and ileum) and large (cecum, ascending colon, and descending colon) intestine occurred in mice administered antibiotics. Communities in antibiotic-treated mice were dominated by a limited number of Clostridium-like (i.e. clostridial cluster XIVa) and Bacteroides species. The richness of mucosa-associated communities within the small and large intestine increased during the 14-day recovery period. However, community profiles within the large intestine did not return to baseline (i.e. relative to the control). Although antibiotic administration greatly reduced bacterial richness, densities of mucosa-associated bacteria were not reduced correspondingly. These data showed that the antibiotics, bacitracin, enrofloxacin, and neomycin sulfate, administered for 21 days to mice did not sterilize the intestine, but did impart a tremendous and prolonged impact on mucosa-associated bacterial communities throughout the small and large intestine. PMID:22185696

Puhl, Nathan J; Uwiera, Richard R E; Yanke, L Jay; Selinger, L Brent; Inglis, G Douglas

2012-02-01

168

A comprehensive metatranscriptome analysis pipeline and its validation using human small intestine microbiota datasets  

PubMed Central

Background Next generation sequencing (NGS) technologies can be applied in complex microbial ecosystems for metatranscriptome analysis by employing direct cDNA sequencing, which is known as RNA sequencing (RNA-seq). RNA-seq generates large datasets of great complexity, the comprehensive interpretation of which requires a reliable bioinformatic pipeline. In this study, we focus on the development of such a metatranscriptome pipeline, which we validate using Illumina RNA-seq datasets derived from the small intestine microbiota of two individuals with an ileostomy. Results The metatranscriptome pipeline developed here enabled effective removal of rRNA derived sequences, followed by confident assignment of the predicted function and taxonomic origin of the mRNA reads. Phylogenetic analysis of the small intestine metatranscriptome datasets revealed a strong similarity with the community composition profiles obtained from 16S rDNA and rRNA pyrosequencing, indicating considerable congruency between community composition (rDNA), and the taxonomic distribution of overall (rRNA) and specific (mRNA) activity among its microbial members. Reproducibility of the metatranscriptome sequencing approach was established by independent duplicate experiments. In addition, comparison of metatranscriptome analysis employing single- or paired-end sequencing methods indicated that the latter approach does not provide improved functional or phylogenetic insights. Metatranscriptome functional-mapping allowed the analysis of global, and genus specific activity of the microbiota, and illustrated the potential of these approaches to unravel syntrophic interactions in microbial ecosystems. Conclusions A reliable pipeline for metatransciptome data analysis was developed and evaluated using RNA-seq datasets obtained for the human small intestine microbiota. The set-up of the pipeline is very generic and can be applied for (bacterial) metatranscriptome analysis in any chosen niche.

2013-01-01

169

Spatial and Temporal Variation of the Intestinal Bacterial Community in Commercially Raised Broiler Chickens During Growth  

Microsoft Academic Search

The objective of this study was to determine whether host, compartment, or environmental specific factors play an important role in the establishment of the intestinal microflora in broiler chickens during growth. This objective was addressed using a 16S rDNA approach. PCR-amplicons from the V6 to V8 regions of the 16S rDNA of intestinal samples were separated by denaturing gradient gel

P. W. J. J. Wielen; D. A. Keuzenkamp; L. J. A. Lipman; F. Knapen; S. Biesterveld

2002-01-01

170

Human Primary Intestinal Epithelial Cells as an Improved In Vitro Model for Cryptosporidium parvum Infection  

PubMed Central

The study of human intestinal pathogens has been limited by the lack of methods for the long-term culture of primary human intestinal epithelial cells (PECs). The development of infection models with PECs would allow a better understanding of host-parasite interactions. The objective of this study was to develop a novel method for prolonged in vitro cultivation of PECs that can be used to study Cryptosporidium infection. We isolated intact crypts from human intestines removed during weight loss surgery. The fragments of intestinal layers were cultivated with culture medium supplemented with growth factors and antiapoptotic molecules. After 7 days, the PECs formed self-regenerating cell clusters, forming villi that resemble intestinal epithelium. The PECs proliferated and remained viable for at least 60 days. The cells expressed markers for intestinal stem cells, epithelial cells, and mature enterocytes. The PECs were infected with Cryptosporidium. In contrast to older models in which parasite numbers decay, the burden of parasites increased for >120 h. In summary, we describe here a novel method for the cultivation of self-regenerating human epithelial cells from small intestinal crypts, which contain both intestinal stem cells and mature villus cells. We present data that suggest these cells support Cryptosporidium better than existing cell lines. PECs should provide an improved tool for studying host-parasite interactions involving Cryptosporidium and other intestinal pathogens.

Cabada, Miguel M.; Nichols, Joan; Gomez, Guillermo; White, A. Clinton

2013-01-01

171

Luminal Bacteria Recruit CD103+ Dendritic Cells into the Intestinal Epithelium to Sample Bacterial Antigens for Presentation  

PubMed Central

SUMMARY CD103+ dendritic cells (DCs) carry bacteria from the small intestine and can present antigens to T cells. Yet they have not been recorded sampling luminal bacteria or presenting bacterial antigens in mesentery lymph nodes. We used 2-photon microscopy in live Cx3cr1+/gfp × Cd11c-YFP mice to study these processes. At steady state, sparse CD103+ DCs occupied the epithelium. They patrolled among enterocytes while extending dendrites toward the lumen, likely using tight-junction proteins to penetrate the epithelium. Challenge with Salmonella triggered chemokine- and toll-like receptor (TLR)-dependent recruitment of additional DCs from the lamina propria (LP). The DCs efficiently phagocytosed the bacteria using intraepithelial dendrites. Noninvasive bacteria were similarly sampled. In contrast, CD103+ DCs sampled soluble luminal antigen inefficiently. In mice harboring CD103+ DCs, antigen-specific CD8 T cells were subsequently activated in MLNs. Intestinal CD103+ DCs are therefore equipped with unique mechanisms to independently complete the processes of uptake, transportation, and presentation of bacterial antigens.

Farache, Julia; Koren, Idan; Milo, Idan; Gurevich, Irina; Kim, Ki-Wook; Zigmond, Ehud; Furtado, Glaucia C.; Lira, Sergio A.; Shakhar, Guy

2014-01-01

172

Seasonal variation in the intestinal bacterial flora of hybrid tilapia ( Oreochromis niloticus× Oreochromis aureus) cultured in earthen ponds in Saudi Arabia  

Microsoft Academic Search

Seasonal quantitative and qualitative analyses of the bacterial flora associated with the intestine of hybrid tilapia (Oreochromis niloticus×Oreochromis aureus) cultured in earthen ponds in Saudi Arabia were carried out. The isolates were being identified to genus or species level. Total viable counts (TVC) of bacteria in the intestine varied between 6.8±1.9×106 to 7.5±1.4×107 colony forming units (cfu) g?1 in early

Ahmed H Al-Harbi; M Naim Uddin

2004-01-01

173

P-glycoprotein-mediated intestinal and biliary digoxin transport in humans  

Microsoft Academic Search

Background and Aims: Intestinal transport by P-glycoprotein is a recently recognized determinant of drug disposition. However, direct measurements of transporter-mediated drug elimination into isolated segments of human small intestine are lacking.Methods: Using a recently developed intestinal perfusion catheter, we perfused in healthy volunteers two 20-cm jejunal segments with and without the P-glycoprotein inhibitor quinidine before and during administration of the

Siegfried Drescher; Hartmut Glaeser; Thomas Mürdter; Monika Hitzl; Michel Eichelbaum; Martin F. Fromm

2003-01-01

174

Small Intestinal Bacterial Overgrowth in Nonalcoholic Steatohepatitis: Association with Toll-Like Receptor 4 Expression and Plasma Levels of Interleukin 8  

Microsoft Academic Search

Background  Experimental and clinical studies suggest an association between small intestinal bacterial overgrowth (SIBO) and nonalcoholic\\u000a steatohepatitis (NASH). Liver injury and fibrosis could be related to exposure to bacterial products of intestinal origin\\u000a and, most notably, endotoxin, including lipopolysaccharide (LPS).\\u000a \\u000a \\u000a \\u000a \\u000a Aim  To compare the prevalence of SIBO and its relationships to LPS receptor levels and systemic cytokines in NASH patients and\\u000a healthy

Ahmed Abu Shanab; Paul Scully; Orla Crosbie; Martin Buckley; Liam O’Mahony; Fergus Shanahan; Sanaa Gazareen; Eileen Murphy; Eamonn M. M. Quigley

2011-01-01

175

Many bacterial species are mitogenic for human blood B lymphocytes.  

PubMed

Thirty bacterial species were tested for their ability to stimulate to increased DNA synthesis in human blood lymphocytes. A definite stimulation was obtained with eighteen bacterial species. For three of these species ten different strains of each were tested, and all increased DNA synthesis. The maximum response was after 3--4 days of culture, suggesting a mitogenic effect. This was confirmed by the induction of polyclonal antibody production shown by a plague assay, which was positive for nine of eleven species tested. Most bacterial species increased the DNA synthesis in B-lymphocyte-enriched and unseparated lymphocytes but had negligible activity on T-lymphocyte-enriched cultures. Among bacteria with a mitogenic effect and ability to induce polyclonal antibody production are Staphylococcus aureus strain Cowan I with a high content of protein A and many common human pathogens such as Haemophilus influenzae, Mycobacterium tuberculosis, Neisseria gonorrhoeae, Streptococcus group A and Streptococcus pneumoniae. PMID:309629

Banck, G; Forsgren, A

1978-01-01

176

Human intestinal MUC17 mucin augments intestinal cell restitution and enhances healing of experimental colitis  

PubMed Central

The membrane-bound mucins, MUC17 (human) and Muc3 (mouse), are highly expressed on the apical surface of intestinal epithelia and are thought to be cytoprotective. The extracellular regions of these mucins contain EGF-like Cys-rich segments (CRD1 and CRD2) connected by an intervening linker domain (L). The purpose of this study was to determine the functional activity of human MUC17 membrane-bound mucin. Methods Endogenous MUC17 was inhibited in LS174T colon cells by stable transfection of a small hairpin RNA targeting MUC17 (LSsi cells). The effect of recombinant MUC17-CRD1-L-CRD2 protein on migration, apoptosis, and experimental colitis was determined. Results Reduced MUC17 expression in LSsi cells was associated with visibly reduced cell aggregation, reduced cell–cell adherence, and reduced cell migration, but no change in tumorigenicity. LSsi cells also demonstrated a 3.7-fold increase in apoptosis rates compared with control cells following treatment with etoposide. Exposure of colonic cell lines to exogenous recombinant MUC17-CRD1-L-CRD2 protein significantly increased cell migration and inhibited apoptosis. As a marker of biologic activity, MUC17-CRD1-L-CRD2 proteins stimulate ERK phosphorylation in colonic cell lines; and inhibition of ERK phosphorylation reduced the anti-apoptosis and migratory effect of MUC17-CRD1-L-CRD2. Finally, mice treated with MUC17-CRD1-L-CRD2 protein given per rectum demonstrated accelerated healing in acetic acid and dextran sodium sulfate induced colitis in vivo. These data indicate that both native MUC17 and the exogenous recombinant cysteine-rich domain of MUC17 play a role in diverse cellular mechanisms related to cell restitution, and suggest a potential role for MUC17-CRD1-L-CRD2 recombinant protein in the treatment of mucosal inflammatory diseases.

Luu, Ying; Junker, Wade; Rachagani, Satyanarayana; Das, Srustidhar; Batra, Surinder K.; Heinrikson, Robert L.; Shekels, Laurie L.; Ho, Samuel B.

2010-01-01

177

Ileocecal valve dysfunction in small intestinal bacterial overgrowth: A pilot study  

PubMed Central

AIM: To explore whether patients with a defective ileocecal valve (ICV)/cecal distension reflex have small intestinal bacterial overgrowth. METHODS: Using a colonoscope, under conscious sedation, the ICV was intubated and the colonoscope was placed within the terminal ileum (TI). A manometry catheter with 4 pressure channels, spaced 1 cm apart, was passed through the biopsy channel of the colonoscope into the TI. The colonoscope was slowly withdrawn from the TI while the manometry catheter was advanced. The catheter was placed across the ICV so that at least one pressure port was within the TI, ICV and the cecum respectively. Pressures were continuously measured during air insufflation into the cecum, under direct endoscopic visualization, in 19 volunteers. Air was insufflated to a maximum of 40 mmHg to prevent barotrauma. All subjects underwent lactulose breath testing one month after the colonoscopy. The results of the breath tests were compared with the results of the pressures within the ICV during air insufflation. RESULTS: Nineteen subjects underwent colonoscopy with measurements of the ICV pressures after intubation of the ICV with a colonoscope. Initial baseline readings showed no statistical difference in the pressures of the TI and ICV, between subjects with positive lactulose breath tests and normal lactulose breath tests. The average peak ICV pressure during air insufflation into the cecum in subjects with normal lactulose breath tests was significantly higher than cecal pressures during air insufflation (49.33 ± 7.99 mmHg vs 16.40 ± 2.14 mmHg, P = 0.0011). The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflations in subjects with normal lactulose breath tests was significantly higher (280.72% ± 43.29% vs 100% ± 0%, P = 0.0006). The average peak ICV pressure during air insufflation into the cecum in subjects with positive lactulose breath tests was not significantly different than cecal pressures during air insufflation 21.23 ± 3.52 mmHg vs 16.10 ± 3.39 mmHg. The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflation was not significantly different 101.08% ± 7.96% vs 100% ± 0%. The total symptom score for subjects with normal lactulose breath tests and subjects with positive lactulose breath tests was not statistically different (13.30 ± 4.09 vs 24.14 ± 6.58). The ICV peak pressures during air insufflations were significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.005). The average percent difference of the area under the pressure curve in the ICV from cecum was significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.0012). Individuals with positive lactulose breath tests demonstrated symptom scores which were significantly higher for the following symptoms: not able to finish normal sized meal, feeling excessively full after meals, loss of appetite and bloating. CONCLUSION: Compared to normal, subjects with a positive lactulose breath test have a defective ICV cecal distension reflex. These subjects also more commonly have higher symptom scores.

Miller, Larry S; Vegesna, Anil K; Sampath, Aiswerya Madanam; Prabhu, Shital; Kotapati, Sesha Krishna; Makipour, Kian

2012-01-01

178

Cloning and expression of the human vasoactive intestinal peptide receptor  

SciTech Connect

Vasoactive intestinal peptide (VIP) is a neuroendocrine mediator found in the central and peripheral nervous systems. Distinct subsets of neural, respiratory, gastrointestinal, and immune cells bear specific high-affinity receptors for VIP, which are associated with a guanine nucleotide-binding (G) protein capable of activatingadenylate cyclase. A cDNA clone (GPRN1) encoding the human VIP receptor was identified in librares prepared from the Nalm 6 line of leukemic pre-B lymphoblasts and the HT-29 line of colon carcinoma cells. The deduced 362-amino acid polypeptide sequence encoded by GPRN1 shares a seven-transmembrane-segment hydropathicity profile with other G protein-coupled receptors. Northern blot analyses identified a 2.7-kilobase transcript of the VIP receptor in Nalm 6 and HT-29 cells as well as in tissues from rat brain, colon, heart, lung, kidney, spleen, and small intestine. COS-6 cells transfected with GPRN1 bound {sup 125}I-labeled VIP specifically with a dissociation constant (K{sub d}) of 2.5 nM. VIP--and less effectively secretin, peptide histidine isoleucine (PHI), and glucagon competitively displaced bound {sup 125}I-VIP from transfected COS-6 cells, with potencies in the order VIP > secretin = PHI >> glucagon. VIP stimulated adenylate cyclase activity in stably transfected Chinese hanster ovary K1 cells, indicing a 3-fold increase in the intracellular level of cAMP. The VIP receptor cloned exhibits {le}24% homology with other receptors in the same superfamily and thus represents a subset of G protein-coupled receptors for peptide ligands.

Sreedharan, S.P.; Robichon, A.; Peterson, K.E.; Goetzl, E.J. (Univ. of California Medical Center, San Francisco (United States))

1991-06-01

179

Cloning and expression of the human vasoactive intestinal peptide receptor.  

PubMed Central

Vasoactive intestinal peptide (VIP) is a neuroendocrine mediator found in the central and peripheral nervous system. Distinct subsets of neural, respiratory, gastrointestinal, and immune cells bear specific high-affinity receptors for VIP, which are associated with a guanine nucleotide-binding (G) protein capable of activating adenylate cyclase. A cDNA clone (GPRN1) encoding the human VIP receptor was identified in libraries prepared from the Nalm 6 line of leukemic pre-B lymphoblasts and the HT-29 line of colon carcinoma cells. The deduced 362-amino acid polypeptide sequence encoded by GPRN1 shares a seven-transmembrane-segment hydropathicity profile with other G protein-coupled receptors. Northern blot analyses identified a 2.7-kilobase transcript of the VIP receptor in Nalm 6 and HT-29 cells as well as in tissues from rat brain, colon, heart, lung, kidney, spleen, and small intestine. COS-6 cells transfected with GPRN1 bound 125I-labeled VIP specifically with a dissociation constant (Kd) of 2.5 nM. VIP--and less effectively secretin, peptide histidine isoleucine (PHI), and glucagon competitively displaced bound 125I-VIP from transfected COS-6 cells, with potencies in the order VIP greater than secretin = PHI much greater than glucagon. VIP stimulated adenylate cyclase activity in stably transfected Chinese hamster ovary K1 cells, inducing a 3-fold increase in the intracellular level of cAMP. When the antisense orientation of the VIP receptor clone was introduced into HT-29 cells, there was a 50% suppression of the specific binding of 125I-VIP and of the VIP-induced increase in cAMP level, relative to untransfected cells. The VIP receptor cloned exhibits less than or equal to 24% homology with other receptors in the same superfamily and thus represents a subset of G protein-coupled receptors for peptide ligands. Images

Sreedharan, S P; Robichon, A; Peterson, K E; Goetzl, E J

1991-01-01

180

Exploration of bacterial community classes in major human habitats  

PubMed Central

Background Determining bacterial abundance variation is the first step in understanding bacterial similarity between individuals. Categorization of bacterial communities into groups or community classes is the subsequent step in describing microbial distribution based on abundance patterns. Here, we present an analysis of the groupings of bacterial communities in stool, nasal, skin, vaginal and oral habitats in a healthy cohort of 236 subjects from the Human Microbiome Project. Results We identify distinct community group patterns in the anterior nares, four skin sites, and vagina at the genus level. We also confirm three enterotypes previously identified in stools. We identify two clusters with low silhouette values in most oral sites, in which bacterial communities are more homogeneous. Subjects sharing a community class in one habitat do not necessarily share a community class in another, except in the three vaginal sites and the symmetric habitats of the left and right retroauricular creases. Demographic factors, including gender, age, and ethnicity, significantly influence community composition in several habitats. Community classes in the vagina, retroauricular crease and stool are stable over approximately 200 days. Conclusion The community composition, association of demographic factors with community classes, and demonstration of community stability deepen our understanding of the variability and dynamics of human microbiomes. This also has significant implications for experimental designs that seek microbial correlations with clinical phenotypes.

2014-01-01

181

Protective effect of glutamine on intestinal injury and bacterial community in rats exposed to hypobaric hypoxia environment  

PubMed Central

AIM: To investigate the protective effect of glutamine (Gln) on intestinal injury and the bacterial community in rats exposed to hypobaric hypoxia environment. METHODS: Sprague-Dawley rats were divided into control, hypobaric hypoxia (HH), and hypobaric hypoxia + Gln (5.0 g/kg BW·d) (HG) groups. On the first 3 d, all rats were placed in a normal environment. After the third day, the HH and HG groups were transferred into a hypobaric chamber at a simulated elevation of 7000 m for 5 d. The rats in the HG group were given Gln by gavage daily for 8 d. The rats in the control and HH groups were treated with the same volume of saline. The intestinal morphology, serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-? (TNF-?), interferon-gamma (IFN-?) and diamino oxidase (DAO) were examined. We also evaluated the expression levels of occludin, toll-like receptor 4 (TLR4), nuclear factor-?B p65 (NF-?B p65) and myeloid differentiation factor 88 (MyD88), and examined the bacterial community in caecal contents. RESULTS: Hypobaric hypoxia induced the enlargement of the heart, liver, lung and kidney, and caused spleen atrophy. Intestinal villi damage was also observed in the HH group. Supplementation with Gln significantly alleviated hypobaric-induced damage to main organs including the intestine, increased serum SOD (1.14 ± 0.03 vs 0.88 ± 0.04, P < 0.05) and MDA (8.35 ± 1.60, P < 0.01) levels and decreased serum IL-6 (1172.13±30.49 vs 1407.05 ± 34.36, P < 0.05), TNF-? (77.46 ± 0.78 vs 123.70 ± 3.03, P < 0.001), IFN-? (1355.42 ± 72.80 vs 1830.16 ± 42.07, P < 0.01) and DAO (629.30 ± 9.15 vs 524.10 ± 13.34, P < 0.001) levels. Moreover, Gln significantly increased occludin (0.72 ± 0.05 vs 0.09 ± 0.01, P < 0.001), TLR4 (0.15 ± 0.05 vs 0.30 ±0.09, P < 0.05), MyD88 (0.32 ± 0.08 vs 0.71 ± 0.06, P < 0.01), and NF-?B p65 (0.16 ± 0.04 vs 0.44 ± 0.03, P < 0.01) expression levels and improved the intestinal bacterial community. CONCLUSION: Gln treatment protects from intestinal injury and regulates the gut flora imbalance in hypoxia environment. These effects may be related to the TLR4/MyD88/NF-?B signaling pathway.

Xu, Chun-Lan; Sun, Rui; Qiao, Xiang-Jin; Xu, Cui-Cui; Shang, Xiao-Ya; Niu, Wei-Ning

2014-01-01

182

Intestinal B-cell isotype response in relation to local bacterial load: Evidence for immunoglobulin A subclass adaptation  

Microsoft Academic Search

Background & Aims: In experimental animals, the indigenous microbiota modulates mucosal immunity. In humans, such direct evidence is scarce. The aim of this study was to examine the effect of intestinal bacteria on the local immunoglobulin (Ig) response. Methods: The numbers of IgA-, IgM-, and IgG-producing immunocytes per defined mucosal length unit were determined, and the local IgA subclass response

Kjell Kett; Kåre Baklien; Arne Bakken; John G. Kral; Olav Fausa; Per Brandtzaeg

1995-01-01

183

Expression of small intestinal and colonic phenotypes in complete intestinal metaplasia of the human stomach  

Microsoft Academic Search

The incomplete intestinal metaplasia (IM) that is reported to be a risk factor for gastric carcinogenesis in man usually features\\u000a sulfomucin production and thus is considered of colonic type. To cast light on the underlying mechanisms, we here examined\\u000a the proportions of colonic and small intestinal phenotypes in IM by immunohistochemistry and real-time reverse transcription–polymerase\\u000a chain reaction at the single

Harunari Tanaka; Tetsuya Tsukamoto; Tsutomu Mizoshita; Ken-ichi Inada; Naotaka Ogasawara; Xueyuan Cao; Sosuke Kato; Takashi Joh; Masae Tatematsu

2005-01-01

184

Molecular analysis of the bacterial microbiota in the human stomach  

PubMed Central

The microbiota of the human stomach and the influence of Helicobacter pylori colonization on its composition remain largely unknown. We characterized bacterial diversity within the human gastric mucosa by using a small subunit 16S rDNA clone library approach and analyzed 1,833 sequences generated by broad-range bacterial PCR from 23 gastric endoscopic biopsy samples. A diverse community of 128 phylotypes was identified, featuring diversity at this site greater than previously described. The majority of sequences were assigned to the Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteria phyla. Ten percent of the phylotypes were previously uncharacterized, including a Deinococcus-related organism, relatives of which have been found in extreme environments but not reported before in humans. The gastric clone libraries from 19 subjects contained H. pylori rDNA; however, only 12 of these subjects tested positive for H. pylori by conventional laboratory methods. Statistical analysis revealed a large degree of intersubject variability of the gastric ecosystem. The presence of H. pylori did not affect the composition of the gastric community. This gastric bacterial rDNA data set was significantly different from sequence collections of the human mouth and esophagus described in other studies, indicating that the human stomach may be home to a distinct microbial eco-system. The gastric microbiota may play important, as-yet-undiscovered roles in human health and disease.

Bik, Elisabeth M.; Eckburg, Paul B.; Gill, Steven R.; Nelson, Karen E.; Purdom, Elizabeth A.; Francois, Fritz; Perez-Perez, Guillermo; Blaser, Martin J.; Relman, David A.

2006-01-01

185

Role of TLR4/NF-?B in Damage to Intestinal Mucosa Barrier Function and Bacterial Translocation in Rats Exposed to Hypoxia  

PubMed Central

The role of Toll-like receptor 4 (TLR4)/nuclear factor-kappa-B (NF-?B) in intestinal mucosal barrier damage and bacterial translocation under hypoxic exposure is unclear. Here, we investigated their role using an acute hypobaric hypoxia model. Adult Sprague-Dawley rats were divided into control (C), hypoxia (H), hypoxia+NF-?B inhibitor pyrrolidinedithiocarbamic acid (PDTC) (100 mg. kg) (HP), hypoxia+0.5 mg/kg lipopolysaccharide (HPL), and hypoxia+PDTC+LPS (HPL) group. Except control group, other four groups were placed in a hypobaric chamber set at 7000 m. Samples were collected at 72 h after pressure reduction. Damage in ultrastructure of the intestinal tract was examined by transmission electron microscopy and bacterial translocation was detected by cultivation. Kinetic turbidimetric assay was used to measure the serum LPS. ELISA was performed to detect TNF-? and IL-6 serum concentrations. Fluorescent quantitative RT-PCR was used to measure TLR4 mRNA levels was measured using quantitative RT-PCR and protein of NF-?B p65 was measured by western blotting. Different degrees of intestinal mucosa damage were observed in groups H and HL. The damage was significantly alleviated after blockage of the TLR4/NF-?B signaling pathway. PDTC- treatment also reversed hyoxia- and LPS-induced bacterial translocation rate and increased serum levels of LPS, TNF-?, and IL-6. TLR4 mRNA levels and NF-?B p65 expression were consistent with the serum factor results. This study suggested that TLR4 and NF-?B expression increased in rat intestinal tissues after acute hypoxia exposure. PDTC-treatment reversed TLR4 and NF-?B upregulation and alleviated damage to the intestinal tract and bacterial translocation. Thus, the TLR4/NF-?B signaling pathway may be critical to the mechanism underlying hypoxia-induced damage to intestinal barrier function and bacterial translocation.

Luo, Han; Guo, Ping; Zhou, Qiquan

2012-01-01

186

Effects of glutamine on intestinal permeability and bacterial translocation in TPN-rats with endotoxemia  

Microsoft Academic Search

AIM: To evaluate the protective effect and mechanism of glutamine on the intestinal barrier function in total parenteral nutrition (TPN) rats with trauma or endotoxemia. METHODS: To perform prospective, randomized and controlled animal experimentation of rats with surgical trauma, TPN and endotoxemia, thirty-four male, adult Sprague Dawley rats were divided into four groups: control group (n=8), TPN group (n=9), trauma

Lian-An Ding; Jie-Show Li

187

Partially responsive celiac disease resulting from small intestinal bacterial overgrowth and lactose intolerance  

Microsoft Academic Search

BACKGROUND: Celiac disease is a common cause of chronic diarrhea and malabsorption syndrome all over the world. Though it was considered uncommon in India in past, it is being described frequently recently. Some patients with celiac disease do not improve despite gluten free diet (GFD). A study described 15 cases of celiac disease unresponsive to GFD in whom small intestinal

Uday C Ghoshal; Ujjala Ghoshal; Asha Misra; Gourdas Choudhuri

2004-01-01

188

Focused specificity of intestinal TH17 cells towards commensal bacterial antigens.  

PubMed

T-helper-17 (TH17) cells have critical roles in mucosal defence and in autoimmune disease pathogenesis. They are most abundant in the small intestine lamina propria, where their presence requires colonization of mice with microbiota. Segmented filamentous bacteria (SFB) are sufficient to induce TH17 cells and to promote TH17-dependent autoimmune disease in animal models. However, the specificity of TH17 cells, the mechanism of their induction by distinct bacteria, and the means by which they foster tissue-specific inflammation remain unknown. Here we show that the T-cell antigen receptor (TCR) repertoire of intestinal TH17 cells in SFB-colonized mice has minimal overlap with that of other intestinal CD4(+) T cells and that most TH17 cells, but not other T cells, recognize antigens encoded by SFB. T cells with antigen receptors specific for SFB-encoded peptides differentiated into ROR?t-expressing TH17 cells, even if SFB-colonized mice also harboured a strong TH1 cell inducer, Listeria monocytogenes, in their intestine. The match of T-cell effector function with antigen specificity is thus determined by the type of bacteria that produce the antigen. These findings have significant implications for understanding how commensal microbiota contribute to organ-specific autoimmunity and for developing novel mucosal vaccines. PMID:24739972

Yang, Yi; Torchinsky, Miriam B; Gobert, Michael; Xiong, Huizhong; Xu, Mo; Linehan, Jonathan L; Alonzo, Francis; Ng, Charles; Chen, Alessandra; Lin, Xiyao; Sczesnak, Andrew; Liao, Jia-Jun; Torres, Victor J; Jenkins, Marc K; Lafaille, Juan J; Littman, Dan R

2014-06-01

189

Differentiation-dependent regulation of intestinal vitamin B2 uptake: studies utilizing human-derived intestinal epithelial Caco-2 cells and native rat intestine  

PubMed Central

Intestinal epithelial cells undergo differentiation as they move from the crypt to the villi, a process that is associated with up- and downregulation in expression of a variety of genes, including those involved in nutrient absorption. Whether the intestinal uptake process of vitamin B2 [riboflavin (RF)] also undergoes differentiation-dependent regulation and the mechanism through which this occurs are not known. We used human-derived intestinal epithelial Caco-2 cells and native rat intestine as models to address these issues. Caco-2 cells showed a significantly higher carrier-mediated RF uptake in post- than preconfluent cells. This upregulation was associated with a significantly higher level of protein and mRNA expression of the RF transporters hRFVT-1 and hRFVT-3 in the post- than preconfluent cells; it was also accompanied with a significantly higher rate of transcription of the respective genes (SLC52A1 and SLC52A3), as indicated by the higher level of expression of heterogeneous nuclear RNA and higher promoter activity in post- than preconfluent cells. Studies with native rat intestine also showed a significantly higher RF uptake by epithelial cells of the villus tip than epithelial cells of the crypt; this again was accompanied by a significantly higher level of expression of the rat RFVT-1 and RFVT-3 at the protein, mRNA, and heterogeneous nuclear RNA levels. These findings show, for the first time, that the intestinal RF uptake process undergoes differentiation-dependent upregulation and suggest that this is mediated (at least in part) via transcriptional mechanisms.

Subramanian, Veedamali S.; Ghosal, Abhisek; Subramanya, Sandeep B.; Lytle, Christian

2013-01-01

190

Antibiotic efficacy in small intestinal bacterial overgrowth–related chronic diarrhea: A crossover, randomized trial  

Microsoft Academic Search

Background & Aims: No controlled trial has examined the clinical efficacy of antibiotics in small bowel bacterial overgrowth. Methods: Ten patients with bacterial overgrowth–related diarrhea underwent the following five 7-day treatment periods: untreated (control period), then placebo, and subsequently, in random order and blinded fashion, norfloxacin (800 mg\\/day), amoxicillin-clavulanic acid (1500 mg\\/day), and Saccharomyces boulardii (1500 mg\\/day). A hydrogen breath

Alain Attar; Bernard Flourié; Claire Franchisseur; Philippe Ruszniewski; Yoram Bouhnik

1999-01-01

191

Correlation between oral drug absorption in humans and apparent drug permeability coefficients in human intestinal epithelial (Caco-2) cells  

Microsoft Academic Search

Monolayers of a well differentiated human intestinal epithelial cell line, Caco-2, were used as a model to study passive drug absorption across the intestinal epithelium. Absorption rate constants (expressed as apparent permeability coefficients) were determined for 20 drugs and peptides with different structural properties. The permeability coefficients ranged from approximately 5 x 10{sup - 8} to 5 x 10{sup -

P. Artursson; J. Karlsson

1991-01-01

192

Adult Human Milk Intolerance and Intestinal Lactase Deficiency: A Review.  

National Technical Information Service (NTIS)

In man, the dietary milk sugar, lactose, is hydrolyzed to glucose and galactose by the small intestinal enzyme, lactase. This enzyme is located in the brush border of the small intestinal epithelial cell. Recent studies have called attention to the associ...

N. S. Rosenweig

1969-01-01

193

Modification of intestinal flora with multispecies probiotics reduces bacterial translocation and improves clinical course in a rat model of acute pancreatitis  

Microsoft Academic Search

Infection of pancreatic necrosis by gut bacteria is a major cause of morbidity and mortality in patients with severe acute pancreatitis. Use of prophylactic antibiotics remains controversial. The aim of this experiment was assess if modification of intestinal flora with specifically designed multispecies probiotics reduces bacterial translocation or improves outcome in a rat model of acute pancreatitis. METHODS: Male Sprague-Dawley

L. Paul van Minnen; Harro M. Timmerman; Femke Lutgendorff; André Verheem; Wil Harmsen; Sergey R. Konstantinov; Hauke Smidt; Maarten R. Visser; Ger T. Rijkers; Hein G. Gooszen; Louis M. A. Akkermans

2007-01-01

194

Comparison of the 1Gram 14C-D-Xylose Breath Test and the 50Gram Hydrogen Glucose Breath Test for Diagnosis of Small Intestinal Bacterial Overgrowth  

Microsoft Academic Search

Background\\/Aims: Culture of small bowel aspirate is the most direct method and the gold standard for diagnosing small intestinal bacterial overgrowth. However, cultures are cumbersome and fluoroscopy is required for obtaining aspirate. Therefore, different breath tests such as the xylose breath test and the hydrogen breath test have been developed. There is no general agreement as to which test is

Per-Ove Stotzer; Anders F. Kilander

2000-01-01

195

Ultrastructural Studies of Intestinal Capillariasis 'Capillaria philippinensis' in Human and Gerbil Hosts.  

National Technical Information Service (NTIS)

Jejunal biopsies from patients with intestinal capillariasis and sections of jejunum obtained at necropsy from experimentally infected Mongolian gerbils were examined by electron microscopy. The ultrastructure of human tissues showed a complete loss of ad...

S. C. Sun J. H. Cross H. S. Berg S. L. Kau C. Singson

1974-01-01

196

Effects of Clindamycin on Adherence of Clostridium difficile to Human Embryonic Intestinal Cells.  

National Technical Information Service (NTIS)

An in vitro assay system, consisting of monolayers of human embryonic intestinal cells (HEI) and Clostridium difficile, was used to observe cell surface and cytoplasmic interactions. Microorganism test conditions include toxin B positive ( 938) and toxin ...

H. P. Dalton S. J. Wood V. Mumaw

1991-01-01

197

Field Emission Scanning Electron Microscopy of the Interaction of Clostridium difficile with Human Embryonic Intestinal Cells.  

National Technical Information Service (NTIS)

An in vitro assay system, consisting of monolayers of human embryonic intestinal cells (HEI) and Clostridium difficile (C. difficile), was used to observe interactions of microorganisms with the cell surface and cytoplasm. Tests were performed using Toxin...

E. Petersen S. Wood

1991-01-01

198

Equivalent uptake of organic and inorganic zinc by monkey kidney fibroblasts, human intestinal epithelial cells, or perfused mouse intestine  

Microsoft Academic Search

Zinc (Zn) is recognized as an essential nutrient, and is added as a supplement to animal and human diets. There are claims\\u000a that zinc methionine (ZnMet) forms a stable complex that is preferentially transported into tissues, and this has contributed\\u000a to uncertainty about conflicting reports on the bioavailability of various Zn compounds. This study evaluated the cellular\\u000a and intestinal uptake

Kathleen T. Beutler; Oleh Pankewycz; David L. Brautigan

1998-01-01

199

Permeability of rhynchophylline across human intestinal cell in vitro  

PubMed Central

Rhynchophylline (Rhy) is the major component of Uncaria species, which is used in Chinese traditional medicine for the treatment of central nervous system disorders. However, its oral bioavailability has not been known. This study aims to investigate the intestinal permeability and related mechanisms of Rhy using cultured human epithelial Caco-2 cells. The cytotoxicity of Rhy on Caco-2 cells was evaluated with MTT assay. The effect of Rhy on the integrity of Caco-2 cell monolayer was assayed with transepithelial electrical resistance. The permeability of Rhy across cell monolayer was assayed by measuring Rhy quantity in received side with HPLC. The effect of Rhy on the expression of P-glycoprotein and MDR1 was detected with Western blot and flow cytometry, respectively. In the concentration of Rhy, which did not produce toxicity on cell viability and integrity of Caco-2 cell monolayer, Rhy crossed the monolayer with velocity 2.76~5.57×10^-6 cm/sec and 10.68~15.66×10^-6 cm/sec from apical to basolateral side and from basolateral to apical side, respectively. The permeability of Rhy was increased by verapamil, a P-glycoprotein inhibitor, or rhodamine123, a P-glycoprotein substrate. Rhy revealed an induction effect on P-glycoprotein expression in Caco-2 cells. These results demonstrate the low permeability of Rhy in intro, and suggest that P-glycoprotein may underlie the mechanism.

Ma, Bo; Wang, Jing; Sun, Jing; Li, Ming; Xu, Huibo; Sun, Guibo; Sun, Xiaobo

2014-01-01

200

Permeability of rhynchophylline across human intestinal cell in vitro.  

PubMed

Rhynchophylline (Rhy) is the major component of Uncaria species, which is used in Chinese traditional medicine for the treatment of central nervous system disorders. However, its oral bioavailability has not been known. This study aims to investigate the intestinal permeability and related mechanisms of Rhy using cultured human epithelial Caco-2 cells. The cytotoxicity of Rhy on Caco-2 cells was evaluated with MTT assay. The effect of Rhy on the integrity of Caco-2 cell monolayer was assayed with transepithelial electrical resistance. The permeability of Rhy across cell monolayer was assayed by measuring Rhy quantity in received side with HPLC. The effect of Rhy on the expression of P-glycoprotein and MDR1 was detected with Western blot and flow cytometry, respectively. In the concentration of Rhy, which did not produce toxicity on cell viability and integrity of Caco-2 cell monolayer, Rhy crossed the monolayer with velocity 2.76~5.57×10^-6 cm/sec and 10.68~15.66×10^-6 cm/sec from apical to basolateral side and from basolateral to apical side, respectively. The permeability of Rhy was increased by verapamil, a P-glycoprotein inhibitor, or rhodamine123, a P-glycoprotein substrate. Rhy revealed an induction effect on P-glycoprotein expression in Caco-2 cells. These results demonstrate the low permeability of Rhy in intro, and suggest that P-glycoprotein may underlie the mechanism. PMID:24966905

Ma, Bo; Wang, Jing; Sun, Jing; Li, Ming; Xu, Huibo; Sun, Guibo; Sun, Xiaobo

2014-01-01

201

Human intestinal absorption-neutral molecules and ionic species.  

PubMed

Analysis of percentage human intestinal absorption (%HIA) for 280 drugs shows that an excellent fit can be obtained using only three descriptors for neutral molecules with a SD of 13.9%. Use of descriptors for individual cations and anions does not lead to any better goodness-of-fit. It is noted that diffusion coefficients in water for ionized molecules are almost identical to those for the corresponding neutral molecules. Comparison of equation coefficients for HIA with those for other processes shows that HIA resembles diffusion in water but does not resemble permeation through biological bilayers. It is shown that compound substituent effects on HIA are near those for diffusion but are far away from substituent effects on permeation through a typical bilayer. Calculations indicate that rates of permeation through an unstirred mucosal layer are of the same order as experimental rates of permeation in HIA. It is concluded that for the 280 compound set, diffusion through the unstirred mucosal layer is the rate determining step. The effect on pKa in transfer of acids and bases from water to another solvent, and of diffusion past a negative charge in a phase/bilayer is also considered. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1956-1966, 2014. PMID:24902952

Abraham, Michael H

2014-07-01

202

Genetic evidence for a protective role of the peritrophic matrix against intestinal bacterial infection in Drosophila melanogaster.  

PubMed

The peritrophic matrix (PM) forms a layer composed of chitin and glycoproteins that lines the insect intestinal lumen. This physical barrier plays a role analogous to that of mucous secretions of the vertebrate digestive tract and is thought to protect the midgut epithelium from abrasive food particles and microbes. Almost nothing is known about PM functions in Drosophila, and its function as an immune barrier has never been addressed by a genetic approach. Here we show that the Drosocrystallin (Dcy) protein, a putative component of the eye lens of Drosophila, contributes to adult PM formation. A loss-of-function mutation in the dcy gene results in a reduction of PM width and an increase of its permeability. Upon bacterial ingestion a higher level of expression of antibacterial peptides was observed in dcy mutants, pointing to an influence of this matrix on bacteria sensing by the Imd immune pathway. Moreover, dcy-deficient flies show an increased susceptibility to oral infections with the entomopathogenic bacteria Pseudomonas entomophila and Serratia marcescens. Dcy mutant flies also succumb faster than wild type upon ingestion of a P. entomophila toxic extract. We show that this lethality is due in part to an increased deleterious action of Monalysin, a pore-forming toxin produced by P. entomophila. Collectively, our analysis of the dcy immune phenotype indicates that the PM plays an important role in Drosophila host defense against enteric pathogens, preventing the damaging action of pore-forming toxins on intestinal cells. PMID:21896728

Kuraishi, Takayuki; Binggeli, Olivier; Opota, Onya; Buchon, Nicolas; Lemaitre, Bruno

2011-09-20

203

Genetic evidence for a protective role of the peritrophic matrix against intestinal bacterial infection in Drosophila melanogaster  

PubMed Central

The peritrophic matrix (PM) forms a layer composed of chitin and glycoproteins that lines the insect intestinal lumen. This physical barrier plays a role analogous to that of mucous secretions of the vertebrate digestive tract and is thought to protect the midgut epithelium from abrasive food particles and microbes. Almost nothing is known about PM functions in Drosophila, and its function as an immune barrier has never been addressed by a genetic approach. Here we show that the Drosocrystallin (Dcy) protein, a putative component of the eye lens of Drosophila, contributes to adult PM formation. A loss-of-function mutation in the dcy gene results in a reduction of PM width and an increase of its permeability. Upon bacterial ingestion a higher level of expression of antibacterial peptides was observed in dcy mutants, pointing to an influence of this matrix on bacteria sensing by the Imd immune pathway. Moreover, dcy-deficient flies show an increased susceptibility to oral infections with the entomopathogenic bacteria Pseudomonas entomophila and Serratia marcescens. Dcy mutant flies also succumb faster than wild type upon ingestion of a P. entomophila toxic extract. We show that this lethality is due in part to an increased deleterious action of Monalysin, a pore-forming toxin produced by P. entomophila. Collectively, our analysis of the dcy immune phenotype indicates that the PM plays an important role in Drosophila host defense against enteric pathogens, preventing the damaging action of pore-forming toxins on intestinal cells.

Kuraishi, Takayuki; Binggeli, Olivier; Opota, Onya; Buchon, Nicolas; Lemaitre, Bruno

2011-01-01

204

Development of a 5-step multi-chamber reactor as a simulation of the human intestinal microbial ecosystem  

Microsoft Academic Search

A five-stage reactor was developed to simulate the gastro-intestinal microbial ecosystem of humans. The small intestine was simulated by a two-step “fill and draw” system, the large intestine by a three-step reactor. A representative supply medium was developed to support a microbial community resembling that of the human gastro-intestinal tract. The entire system was validated by monitoring fermentation fluxes and

K. Molly; M. Vande Woestyne; W. Verstraete

1993-01-01

205

Identification of the transcriptional response of human intestinal mucosa to Lactobacillus plantarum WCFS1 in vivo  

Microsoft Academic Search

BACKGROUND: There is limited knowledge on the extent and dynamics of the mucosal response to commensal and probiotic species in the human intestinal lumen. This study aimed to identify the acute, time-dependent responses of intestinal mucosa to commensal Lactobacillus plantarum WCFS1 in vivo in two placebo-controlled human intervention studies in healthy volunteers. Transcriptional changes in duodenal mucosa upon continuous intraduodenal

Freddy J Troost; Peter van Baarlen; Patrick Lindsey; Andrea Kodde; Willem M de Vos; Michiel Kleerebezem; Robert-Jan M Brummer

2008-01-01

206

Characterization of intracellular pteroylpolyglutamate hydrolase (PPH) from human intestinal mucosa  

SciTech Connect

There are two forms of pteroylpolyglutamate hydrolase (PPH) in the human intestinal mucosa, one in the brush border membrane and the other intracellular; brush border PPH is an exopeptidase with optimal activity at pH 6.5 and a requirement for zinc. The presence study characterized human intracellular PPH and compared its properties to those of brush border PPH. Intracellular PPH was purified 30-fold. The enzyme had a MW of 75,000 by gel filtration, was optimally active at pH 4.5, and had an isoelectric point at pH 8.0. In contrast to brush border PPH, intracellular PPH was unstable at increasing temperatures, was unaffected by dialysis against chelating agents and showed no requirement for Zn/sup 2 +/. Using PteGlu/sub 2/(/sup 14/C)Glu as substrate, they demonstrated a K/sub m/ of 1.2 ..mu..M and increasing affinity for folates with longer glutamate chains. Intracellular PPH required the complete folic acid (PteGlu) moiety and a ..gamma..-glutamyl linkage for activity. Using ion exchange chromatography and an HPLC method to determine the hydrolytic products of the reaction, they found intracellular PPH could cleave both internal and terminal ..gamma..-glutamyl linkages, with PteGlu as an end product. After subcellular fractionation of the mucosa, PPH was found in the lysosomes. In summary, the distinct characteristics of brush border and intracellular PPH suggest that the two hydrolases serve different roles in folate metabolism.

Wang, T.T.Y.; Chandler, C.J.; Halsted, C.H.

1986-03-01

207

Butyrate produced by commensal bacteria potentiates phorbol esters induced AP-1 response in human intestinal epithelial cells.  

PubMed

The human intestine is a balanced ecosystem well suited for bacterial survival, colonization and growth, which has evolved to be beneficial both for the host and the commensal bacteria. Here, we investigated the effect of bacterial metabolites produced by commensal bacteria on AP-1 signaling pathway, which has a plethora of effects on host physiology. Using intestinal epithelial cell lines, HT-29 and Caco-2, stably transfected with AP-1-dependent luciferase reporter gene, we tested the effect of culture supernatant from 49 commensal strains. We observed that several bacteria were able to activate the AP-1 pathway and this was correlated to the amount of short chain fatty acids (SCFAs) produced. Besides being a major source of energy for epithelial cells, SCFAs have been shown to regulate several signaling pathways in these cells. We show that propionate and butyrate are potent activators of the AP-1 pathway, butyrate being the more efficient of the two. We also observed a strong synergistic activation of AP-1 pathway when using butyrate with PMA, a PKC activator. Moreover, butyrate enhanced the PMA-induced expression of c-fos and ERK1/2 phosphorylation, but not p38 and JNK. In conclusion, we showed that SCFAs especially butyrate regulate the AP-1 signaling pathway, a feature that may contribute to the physiological impact of the gut microbiota on the host. Our results provide support for the involvement of butyrate in modulating the action of PKC in colon cancer cells. PMID:23300800

Nepelska, Malgorzata; Cultrone, Antonietta; Béguet-Crespel, Fabienne; Le Roux, Karine; Doré, Joël; Arulampalam, Vermulugesan; Blottière, Hervé M

2012-01-01

208

The Intestinal Archaea Methanosphaera stadtmanae and Methanobrevibacter smithii Activate Human Dendritic Cells  

PubMed Central

The methanoarchaea Methanosphaera stadtmanae and Methanobrevibacter smithii are known to be part of the indigenous human gut microbiota. Although the immunomodulatory effects of bacterial gut commensals have been studied extensively in the last decade, the impact of methanoarchaea in human's health and disease was rarely examined. Consequently, we studied and report here on the effects of M. stadtmanae and M. smithii on human immune cells. Whereas exposure to M. stadtmanae leads to substantial release of proinflammatory cytokines in monocyte-derived dendritic cells (moDCs), only weak activation was detected after incubation with M. smithii. Phagocytosis of M. stadtmanae by moDCs was demonstrated by confocal microscopy as well as transmission electronic microscopy (TEM) and shown to be crucial for cellular activation by using specific inhibitors. Both strains, albeit to different extents, initiate a maturation program in moDCs as revealed by up-regulation of the cell-surface receptors CD86 and CD197 suggesting additional activation of adaptive immune responses. Furthermore, M. stadtmanae and M. smithii were capable to alter the gene expression of antimicrobial peptides in moDCs to different extents. Taken together, our findings strongly argue that the archaeal gut inhabitants M. stadtmanae and M. smithii are specifically recognized by the human innate immune system. Moreover, both strains are capable of inducing an inflammatory cytokine response to different extents arguing that they might have diverse immunomodulatory functions. In conclusion, we propose that the impact of intestinal methanoarchaea on pathological conditions involving the gut microbiota has been underestimated until now.

Bang, Corinna; Weidenbach, Katrin; Gutsmann, Thomas

2014-01-01

209

Morphology of Diagnostic Stages of Intestinal Parasites of Humans.  

National Technical Information Service (NTIS)

The diagnostic stages of intestinal parasites are differentiated on the basis of specific morphologic features that can be seen microscopically. Although Dientamoeba fragilis is a flagellate, morphologically, it resembles the amebae. Therefore, in this ma...

M. M. Brooke D. M. Melvin

1984-01-01

210

[The possibility of colonizing the intestines of white mice with Lactobacillus acidophilus during bacterial therapy].  

PubMed

The study revealed the possibility, on principle, for L. acidophilus strain VKM V-2020 D to colonize the intestine of white mice with the preservation of the viability of lactobacilli subjected to the action of antibiotics. The culture of this strain, isolated from the animals, showed the stability of its biological properties: resistance to polymyxin M, kanamycin, cyprofloxacin, nalidixic acid (including acquired resistance to rifampicin), as well as pronounced antagonism with respect to Vibrio cholerae. Good prospects for the use of L. acidophilus strain VKM V-2020 D for further studies regarding its use for prophylaxis and therapy were noted. PMID:9221664

Kruglikov, V D; Tsuraeva, R I; Ryzhko, I V; Drobotkovskaia, N V; Kuchin, V V; Bardykh, I D; Pushkareva, N D

1997-01-01

211

Nerveless and gutsy: intestinal nutrient sensing from invertebrates to humans.  

PubMed

The increasingly recognized role of gastrointestinal signals in the regulation of food intake, insulin production and peripheral nutrient storage has prompted a surge of interest in studying how the gastrointestinal tract senses and responds to nutritional information. Identification of metabolically important intestinal nutrient sensors could provide potential new drug targets for the treatment of diabetes, obesity and gastrointestinal disorders. From a more fundamental perspective, the study of intestinal chemosensation is revealing novel, non-neuronal modes of communication involving differentiated epithelial cells. It is also identifying signalling mechanisms downstream of not only canonical receptors but also nutrient transporters, thereby supporting a chemosensory role for "transceptors" in the intestine. This review describes known and proposed mechanisms of intestinal carbohydrate, protein and lipid sensing, best characterized in mammalian systems. It also highlights the potential of invertebrate model systems such as C. elegans and Drosophila melanogaster by summarizing known examples of molecular evolutionary conservation. Recently developed genetic tools in Drosophila, an emerging model system for the study of physiology and metabolism, allow the temporal, spatial and high-throughput manipulation of putative intestinal sensors. Hence, fruit flies may prove particularly suited to the study of the link between intestinal nutrient sensing and metabolic homeostasis. PMID:22248674

Miguel-Aliaga, Irene

2012-08-01

212

Nerveless and gutsy: intestinal nutrient sensing from invertebrates to humans  

PubMed Central

The increasingly recognized role of gastrointestinal signals in the regulation of food intake, insulin production and peripheral nutrient storage has prompted a surge of interest in studying how the gastrointestinal tract senses and responds to nutritional information. Identification of metabolically important intestinal nutrient sensors could provide potential new drug targets for the treatment of diabetes, obesity and gastrointestinal disorders. From a more fundamental perspective, the study of intestinal chemosensation is revealing novel, non-neuronal modes of communication involving differentiated epithelial cells. It is also identifying signalling mechanisms downstream of not only canonical receptors but also nutrient transporters, thereby supporting a chemosensory role for “transceptors” in the intestine. This review describes known and proposed mechanisms of intestinal carbohydrate, protein and lipid sensing, best characterized in mammalian systems. It also highlights the potential of invertebrate model systems such as C. elegans and Drosophila melanogaster by summarizing known examples of molecular evolutionary conservation. Recently developed genetic tools in Drosophila, an emerging model system for the study of physiology and metabolism, allow the temporal, spatial and high-throughput manipulation of putative intestinal sensors. Hence, fruit flies may prove particularly suited to the study of the link between intestinal nutrient sensing and metabolic homeostasis.

Miguel-Aliaga, Irene

2012-01-01

213

Diversity and Succession of the Intestinal Bacterial Community of the Maturing Broiler Chicken  

Microsoft Academic Search

The diversity of bacterial floras in the ilea and ceca of chickens that were fed a vegetarian corn-soy broiler diet devoid of feed additives was examined by analysis of 1,230 partial 16S rRNA gene sequences. Nearly 70% of sequences from the ileum were related to those of Lactobacillus, with the majority of the rest being related to Clostridiaceae (11%), Streptococcus

Jiangrang Lu; Umelaalim Idris; Barry Harmon; Charles Hofacre; John J. Maurer; Margie D. Lee

2003-01-01

214

Interindividual variability of carboxymethylenebutenolidase homolog, a novel olmesartan medoxomil hydrolase, in the human liver and intestine.  

PubMed

Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor antagonist. OM is rapidly converted into its active metabolite olmesartan by multiple hydrolases in humans, and we recently identified carboxymethylenebutenolidase homolog (CMBL) as one of the OM bioactivating hydrolases. In the present study, we further investigated the interindividual variability of mRNA and protein expression of CMBL and OM-hydrolase activity using 40 individual human liver and 30 intestinal specimens. In the intestinal samples, OM-hydrolase activity strongly correlated with the CMBL protein expression, clearly indicating that CMBL is a major contributor to the prodrug bioactivation in human intestine. The protein and activity were highly distributed in the proximal region (duodenum and jejunum) and decreased to the distal region of the intestine. Although there was high interindividual variability (16-fold) in both the protein and activity in the intestinal segments from the duodenum to colon, the interindividual variability in the duodenum and jejunum was relatively small (3.0- and 2.4-fold, respectively). In the liver samples, the interindividual variability in the protein and activity was 4.1- and 6.8-fold, respectively. No sex differences in the protein and activity were shown in the human liver or intestine. A genetically engineered Y155C mutant of CMBL, which was caused by a single nucleotide polymorphism rs35489000, showed significantly lower OM-hydrolase activity than the wild-type protein although no minor allele was genotyped in the 40 individual liver specimens. PMID:23471504

Ishizuka, Tomoko; Rozehnal, Veronika; Fischer, Thomas; Kato, Ayako; Endo, Seiko; Yoshigae, Yasushi; Kurihara, Atsushi; Izumi, Takashi

2013-05-01

215

Beta adrenergic modulation of human upper intestinal propulsive forces.  

PubMed Central

beta Adrenoceptor blockade is known to accelerate transit through the small intestine without changing either the number or pattern of intestinal contractions. This study therefore tested the hypothesis that an increase in intraluminal aboral propulsive force may contribute to this transit acceleration. Twenty paired studies were performed, in 10 healthy volunteers, after oral administration of either 100 mg atenolol (a selective beta 1 antagonist) or matched dummy tablets according to a double blind, randomised protocol. The frequency of occurrence of, and the propulsive force exerted by, traction events related to intestinal contractions were measured, using a combined traction force detector and manometry assembly. After atenolol, a consistent increase in the force generated per traction event was noted, both for propagating contractions mean (SEM) (12.0 (1.8) g v control 5.9 (0.07) g; p < 0.05) and for stationary (11.6 (1.4) g v control 7.0 (0.7) g; p < 0.05). In contrast no change in the number of traction events was noted (control v atenolol = 1.6 (0.3) v 1.64 (0.4) per min for propagating and 0.7 (0.1) v 0.85 (0.16) per min for stationary contraction; p > 0.05). beta Adrenoceptor blockade thus increases the propulsive force generated by intestinal contractions, possibly by removing a sympathetic neural inhibition of intestinal tone.

Ahluwalia, N K; Thompson, D G; Barlow, J; Heggie, L

1994-01-01

216

Bacterial Type IV Secretion Systems in Human Disease  

PubMed Central

Summary Type IV secretion (T4S) systems are versatile machines involved in many processes relevant to bacterial virulence, such as horizontal DNA transfer and effector translocation into human cells. A recent Workshop organized by the International University of Andalousia (UNIA) in Baeza, Spain, covered most aspects of bacterial T4S relevant to human disease, ranging from the structural and mechanistic analysis of the T4S systems to the physiological roles of the translocated effector proteins in subverting cellular functions in infected humans. This review reports the highlights from this workshop, which include the first visualization of a T4S system core complex spanning both membranes of Gram-negative bacteria, the identification of the first host receptors for T4S systems, the identification and characterization of novel T4S effector proteins, the analysis of the molecular function of effector proteins in subverting human cellular functions, and an analysis of the role of T4S systems in the evolution of pathogenic bacteria. Our increasing knowledge of the biology of T4S improves our ability to exploit them as biotechnological tools or to use them as novel targets for a new generation of antimicrobials.

Llosa, Matxalen; Roy, Craig; Dehio, Christoph

2009-01-01

217

Notch2-dependent classical dendritic cells orchestrate intestinal immunity against attaching and effacing bacterial pathogens  

PubMed Central

Defense against attaching and effacing (A/E) bacteria requires the sequential generation of interleukin 23 (IL-23) and IL-22 to induce protective mucosal responses. While CD4+ and NKp46+ innate lymphoid cells (ILCs) are the critical source of IL-22 during infection, the precise source of IL-23 is unclear. We used genetic techniques to deplete specific subsets of classical dendritic cells (cDCs) and analyzed immunity to the A/E pathogen Citrobacter rodentium. We found that Notch2 controlled the terminal stage of cDC differentiation. Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, were an obligate source of IL-23 required to survive C. rodentium infection. These results provide the first demonstration of a non-redundant function of CD11b+ cDCs in response to pathogens in vivo.

Satpathy, Ansuman T.; Briseno, Carlos G.; Lee, Jacob S.; Ng, Dennis; Manieri, Nicholas A.; KC, Wumesh; Wu, Xiaodi; Thomas, Stephanie R.; Lee, Wan-Ling; Turkoz, Mustafa; McDonald, Keely G.; Meredith, Matthew M.; Song, Christina; Guidos, Cynthia J.; Newberry, Rodney D.; Ouyang, Wenjun; Murphy, Theresa L.; Stappenbeck, Thaddeus S.; Gommerman, Jennifer L.; Nussenzweig, Michel C.; Colonna, Marco; Kopan, Raphael; Murphy, Kenneth M.

2013-01-01

218

Mechanism of conjugated linoleic acid and vaccenic acid formation in human faecal suspensions and pure cultures of intestinal bacteria.  

PubMed

Faecal bacteria from four human donors and six species of human intestinal bacteria known to metabolize linoleic acid (LA) were incubated with LA in deuterium oxide-enriched medium to investigate the mechanisms of conjugated linoleic acid (CLA) and vaccenic acid (VA) formation. The main CLA products in faecal suspensions, rumenic acid (cis-9,trans-11-CLA; RA) and trans-9,trans-11-CLA, were labelled at C-13, as were other 9,11 geometric isomers. Traces of trans-10,cis-12-CLA formed were labelled to a much lower extent. In pure culture, Bifidobacterium breve NCFB 2258 formed labelled RA and trans-9,trans-11-CLA, while Butyrivibrio fibrisolvens 16.4, Roseburia hominis A2-183T, Roseburia inulinivorans A2-192T and Ruminococcus obeum-like strain A2-162 converted LA to VA, labelled in a manner indicating that VA was formed via C-13-labelled RA. Propionibacterium freudenreichii subsp. shermanii DSM 4902T, a possible probiotic, formed mainly RA with smaller amounts of trans-10,cis-12-CLA and trans-9,trans-11-CLA, labelled the same as in the mixed microbiota. Ricinoleic acid (12-OH-cis-9-18 : 1) did not form CLA in the mixed microbiota, in contrast to CLA formation described for Lactobacillus plantarum. These results were similar to those reported for the mixed microbiota of the rumen. Thus, although the bacterial genera and species responsible for biohydrogenation in the rumen and the human intestine differ, and a second route of RA formation via a 10-OH-18 : 1 is present in the intestine, the overall labelling patterns of different CLA isomers formation are common to both gut ecosystems. A hydrogen-abstraction enzymic mechanism is proposed that may explain the role of a 10-OH-18 : 1 intermediate in 9,11-CLA formation in pure and mixed cultures. PMID:19118369

McIntosh, Freda M; Shingfield, Kevin J; Devillard, Estelle; Russell, Wendy R; Wallace, R John

2009-01-01

219

Isolation and Identification of Intestinal CYP3A Inhibitors from Cranberry (Vaccinium macrocarpon) using Human Intestinal Microsomes  

PubMed Central

Cranberry juice is used routinely, especially among women and the elderly, to prevent and treat urinary tract infections. These individuals are likely to be taking medications concomitantly with cranberry juice, leading to concern about potential drug-dietary substance interactions, particularly in the intestine, which, along with the liver, is rich in expression of the prominent drug metabolizing enzyme, cytochrome P450 3A (CYP3A). Using a systematic in vitro-in vivo approach, a cranberry juice product was identified recently that elicited a pharmacokinetic interaction with the CYP3A probe substrate midazolam in 16 healthy volunteers. Relative to water, a cranberry juice inhibited intestinal first-pass midazolam metabolism. In vitro studies were initiated to identify potential enteric CYP3A inhibitors from cranberry via a bioactivity-directed fractionation approach involving dried whole cranberry [Vaccinium macrocarpon Ait. (Ericaceae)], midazolam, and human intestinal microsomes (HIM). Three triterpenes (maslinic acid, corosolic acid, and ursolic acid) were isolated. The inhibitory potency (IC50) of maslinic acid, corosolic acid, and ursolic acid was 7.4, 8.8, and <10 ?M, respectively, using HIM as the enzyme source and was 2.8, 4.3, and <10 ?M, respectively, using recombinant CYP3A4 as the enzyme source. These in vitro inhibitory potencies, which are within the range of those reported for two CYP3A inhibitory components in grapefruit juice, suggest that these triterpenes may have contributed to the midazolam-cranberry juice interaction observed in the clinical study.

Kim, Eunkyung; Sy-Cordero, Arlene; Graf, Tyler N.; Brantley, Scott J.; Paine, Mary F.; Oberlies, Nicholas H.

2010-01-01

220

Long Chain Fatty Acid Uptake by Human Intestinal Mucosa in vitro: Mechanisms of Transport  

Microsoft Academic Search

Background\\/Aims: The aim of this study was to investigate whether a carrier-mediated membrane transport for long chain fatty acid (LCFA) exists in the human intestinal mucosa. Methods: Biopsies obtained from the small intestine of patients, during routine endoscopies, were incubated for different periods in the presence of [3H]oleic acid complexed to albumin, and lipid fractions were separated and quantified. Biopsies

Célia Regina M. Chaves; Paulo Roberto P. Elias; Wanli Cheng; Cyrla Zaltman; Antônio Carlos R. Iglesias; Valeria B. Braulio

2003-01-01

221

Identification of the metabolites of myricitrin produced by human intestinal bacteria in vitro using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry.  

PubMed

Objective: To investigate the metabolic routes and metabolites of myricitrin, an important active ingredient of traditional herbal medicine, yielded by the isolated human intestinal bacteria, which have not been reported previously. Methods: Fresh human fecal samples were collected from a healthy female volunteer and about 100 different bacterial colonies were isolated. Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry technique combined with Metabolynx™ software was used for analysis of the metabolic profile of myricitrin by the isolated human intestinal bacteria. Results: One hundred different bacterial colonies, which developed on plates, were picked up, and four of them were further identified by using the technique of 16S rRNA gene sequencing due to their relatively strong metabolic capacity toward myricitrin. Most of them belong to Escherichia. Parent compound and three metabolites (quercetin-3-O-rhamnoside, myricetin and quercetin) were detected in the isolated bacterial samples compared with blank samples. The metabolic pathways of myricitrin included deglycosylation and dehydroxylation. Conclusions: These metabolites suggested that myricitrin was first dehydroxylated to quercetin-3-O-rhamnoside and subsequently deglycosylated to quercetin. Additionally, myricitrin could also be deglycosylated to the aglycon myricetin. Moreover, those metabolites might influence the biological effect of myricitrin in vivo, which led to affect the clinical effects of the medicinal plants and traditional herb medicines. PMID:24882500

Du, Le-Yue; Zhao, Min; Xu, Jun; Qian, Da-Wei; Jiang, Shu; Shang, Er-Xin; Guo, Jian-Ming; Liu, Pei; Su, Shu-Lan; Duan, Jin-Ao; Leng, Xue-Jiao

2014-07-01

222

The role of disulphide bonds in human intestinal mucin  

PubMed Central

Goblet-cell mucin (mucin 1) was isolated and purified from human small-intestinal scrapings. After application of mucin 1 to DEAE-Bio-Gel (A) columns, most of the glycoprotein (76–94% of hexoses) was eluted in the first peak (designated mucin 2). Minor amounts of acidic glycoproteins were eluted with 0.2m- and 0.4m-NaCl in later peaks. Analyses of mucin 1 and mucin 2 revealed mucin 2 to be a monodisperse highly glycosylated glycoprotein containing 6.3% by wt. of protein, N-acetylgalactosamine, N-acetylglucosamine, galactose and fucose. Mucin 1 was similar in composition, but was polydisperse and contained more protein (12.3% by wt.) as well as N-acetylneuraminic acid. Analytical CsCl-gradient ultracentrifugation showed both mucin 1 and mucin 2 to have a major component with an average buoyant density of 1.47000g/ml. Mucin 1 also contained a slightly less-dense minor glycoprotein component. After exhaustive reduction and alkylation mucin 1 retained its major component, but partly dissociated into two lighter glycoprotein components. Mucin 2, in contrast, did not change its density distribution after reduction. Band ultracentrifugation in 2H2O-containing iso-osmotic buffers showed that mucin 1 contained a major fast-sedimenting component (so=37±2S), and a minor amount of a slower-sedimenting component. After reduction there was an increased quantity of the latter component, for which an so value of 14.5S was calculated. In contrast, mucin 2 was unaltered by reduction (so=33±2S). These findings indicate that the major component of goblet-cell mucin (mucin 2) does not dissociate after S–S-bond reduction, and thus does not apparently rely for its polymeric structure on the association of subunits through covalent disulphide bonds. However, the effects of reduction on mucin 1 suggest that in the native mucin intramolecular disulphide bonds in the minor glycoproteins may stabilize their structure, permitting secondary non-covalent interactions to develop with the major dense mucin (mucin 2) protein. ImagesFig. 2.Fig. 3.Fig. 4.

Forstner, Janet F.; Jabbal, Inderjit; Qureshi, Rauf; Kells, David I. C.; Forstner, Gordon G.

1979-01-01

223

Survival of Lactic Acid Bacteria in the Human Stomach and Adhesion to Intestinal Cells  

Microsoft Academic Search

The survival of four strains of lactic acid bacteria in human gastric juice, in vivo and in vitro, and in buffered saline, pH 1 to 5, has been investigated. The strains studied include two Lactobacillus acidophilus strains, Lactobacillus bul- garicus, and Streptococcus thermophilus. In addition, the adhesion of these strains to freshly collected human and pig small intestinal cells and

P. L. Conway; S. L. Gorbach; B. R. Goldin

1987-01-01

224

Mast cells are an important cellular source of tumour necrosis factor ? in human intestinal tissue  

PubMed Central

BACKGROUND—Several inflammatory disorders of the intestine are characterised by enhanced expression of tumour necrosis factor ? (TNF-?). Monocytes and macrophages have been suggested as a major cellular source of TNF-? in human gut, whereas mast cells, although known to be capable of producing TNF-?, have been poorly examined in this respect. ?AIMS—To investigate whether human intestinal mast cells can produce TNF-?, and which factors regulate TNF-? production in these cells. ?METHODS—Mast cells were isolated from surgery tissue specimens of patients undergoing bowel resection because of cancer. Immunohistochemical studies were performed in biopsy specimens derived from 13 patients (two healthy controls, four with Crohn's disease, four with ulcerative colitis, three others). TNF-? mRNA and protein expression were studied in vitro by polymerase chain reaction, RNAse protection assay, western blot, and enzyme linked immunosorbent assay in isolated purified human intestinal mast cells stimulated by IgE receptor crosslinking, intestinal bacteria, and lipopolysaccharide. Cellular localisation of TNF-? was examined by immunohistochemistry. ?RESULTS—TNF-? mRNA and protein were expressed constitutively in isolated human intestinal mast cells. Expression of TNF-? mRNA and release of TNF-? protein were substantially enhanced by IgE receptor crosslinking and by coculture of mast cells with intestinal bacteria; lipopolysaccharide had only marginal effects. Immunohistochemical studies revealed that approximately 60% of the lamina propria cells with immunoreactivity for TNF-? were mast cells. ?CONCLUSIONS—The data show that mast cells are an important source of TNF-? in the human intestinal mucosa. ?? Keywords: tumour necrosis factor; mast cells; inflammatory bowel disease; bacteria

Bischoff, S; Lorentz, A; Schwengberg, S; Weier, G; Raab, R; Manns, M

1999-01-01

225

Human intestinal epithelial and smooth muscle cells are potent producers of IL-6.  

PubMed Central

BACKGROUND: Interleukin-6 (IL-6), a pluripotent cytokine, has traditionally been considered the product of proinflammatory cells. However, many other cell types have been shown to produce IL-6. Since intestinal inflammation is commonly associated with a vigorous systemic inflammatory response, we hypothesized that intestinal epithelial and smooth muscle cells might contribute to that response by producing IL-6. We therefore studied the capacity of differentiated human intestinal epithelial and smooth muscle cell lines to produce IL-6 in response to various proinflammatory stimuli. MATERIALS AND METHODS: CCL-241, a human intestinal epithelial cell line, and HISM, a human intestinal muscle cell line, were grown to confluency and then treated for 24 h with various concentrations of lipopolysaccharide, Clostridium difficile culture extract containing both toxin A and toxin B, recombinant human tumor necrosis factor-alpha (TNF-alpha), or recombinant human interleukin-1 beta (IL-1beta). Supernatants were then collected for IL-6 determination using an enzyme-linked immunosorbent assay. Cell numbers were determined using a Coulter counter. For comparison, parallel studies were performed using phorbol ester-primed U-937 and THP-1 human macrophage cell lines. RESULTS: Both human intestinal epithelial and smooth muscle cells produced IL-6 under basal conditions. In HISM cells, but not in CCL-241 cells, IL-6 release was increased slightly by treatment with C. difficile culture extract containing both toxin A and toxin B and with lipopolysaccharide. In both cell lines, IL-6 production was profoundly stimulated by treatment with IL-1beta and less so with TNF-alpha. Combinations of high-dose TNF-alpha and IL-1beta may have a slightly additive, but not synergistic, effect on IL-6 release. The amount of IL-6 produced by IL-1-stimulated intestinal cell lines was 70-fold higher than that produced by stimulated macrophage cell lines. CONCLUSIONS; Both intestinal epithelial and smooth muscle cells demonstrate the ability to release significant amounts of IL-6. The profound response to IL-1beta and TNF-alpha stimulation by both cell lines suggests that human intestinal parenchymal cells, influenced by paracrine mediators liberated from proinflammatory cells, might significantly contribute to the overall systemic inflammatory response by producing IL-6.

Ng, Edmond K; Panesar, Ninder; Longo, Walter E; Shapiro, Marc J; Kaminski, Donald L; Tolman, Kym C; Mazuski, John E

2003-01-01

226

Immunostimulators recommended case secondary (acquired) immunodeficiency invasions helmints bacterial viral infections disorders nutrient resorbtion deficiency intestine kidney functions diabetes after narcosis burns after treatment Ionizing radiation other adverse environmental effects  

EPA Pesticide Factsheets

Did you mean: Immunostimulators recommended case secondary (acquired) immunodeficiency invasions helmints bacterial viral infections disorders nutrient resorbtion deficiency intestine kidney functions diabetes after narcosis burns after treatment Ionizing radiation other adverse environmental effects ?

227

Anti-apoptotic PI3K\\/Akt signaling by sodium\\/glucose transporter 1 reduces epithelial barrier damage and bacterial translocation in intestinal ischemia  

Microsoft Academic Search

Intestinal ischemia\\/reperfusion (I\\/R) causes mucosal barrier damage and bacterial translocation (BT), leading to septic complications. Previous in vitro studies showed that activation of sodium\\/glucose transporter 1 (SGLT1) prevented the epithelial apoptosis and permeability rise induced by microbial products. Our aim was to investigate whether luminal glucose uptake by SGLT1 protects against ischemia-induced epithelial cell death and barrier dysfunction, and to

Ching-Ying Huang; Jong-Kai Hsiao; Yen-Zhen Lu; Tsung-Chun Lee; Linda C-H Yu

2011-01-01

228

Culture-based and denaturing gradient gel electrophoresis analysis of the bacterial community structure from the intestinal tracts of earthworms(Eisenia fetida).  

PubMed

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and - independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culture-dependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms. PMID:21952364

Hong, Sung Wook; Kim, In Su; Lee, Ju Sam; Chung, Kun Sub

2011-09-01

229

Influence of Camembert consumption on the composition and metabolism of intestinal microbiota: a study in human microbiota-associated rats.  

PubMed

The objective of the present study was to evaluate the consequence of Camembert consumption on the composition and metabolism of human intestinal microbiota. Camembert cheese was compared with milk fermented by yoghurt starters and Lactobacillus casei as a probiotic reference. The experimental model was the human microbiota-associated (HM) rat. HM rats were fed a basal diet (HMB group), a diet containing Camembert made from pasteurised milk (HMCp group) or a diet containing fermented milk (HMfm group). The level of micro-organisms from dairy products was measured in faeces using cultures on a specific medium and PCR-temporal temperature gradient gel electrophoresis. The metabolic characteristics of the caecal microbiota were also studied: SCFA, NH3, glycosidase and reductase activities, and bile acid degradations. The results showed that micro-organisms from cheese comprised 10(5)-10(8) bacteria/g faecal sample in the HMCp group. Lactobacillus species from fermented milk were detected in HMfm rats. Consumption of cheese and fermented milk led to similar changes in bacterial metabolism: a decrease in azoreductase activity and NH3 concentration and an increase in mucolytic activities. However, specific changes were observed: in HMCp rats, the proportion of ursodeoxycholic resulting from chenodeoxycholic epimerisation was higher; in HMfm rats, alpha and beta-galactosidases were higher than in other groups and both azoreductases and nitrate reductases were lower. The results show that, as for fermented milk, Camembert consumption did not greatly modify the microbiota profile or its major metabolic activities. Ingested micro-organisms were able to survive in part during intestinal transit. These dairy products exert a potentially beneficial influence on intestinal metabolism. PMID:15469646

Lay, Christophe; Sutren, Malène; Lepercq, Pascale; Juste, Catherine; Rigottier-Gois, Lionel; Lhoste, Evelyne; Lemée, Riwanon; Le Ruyet, Pascale; Doré, Joël; Andrieux, Claude

2004-09-01

230

Human Intestinal Tissue with Adult Stem Cell Properties Derived from Pluripotent Stem Cells  

PubMed Central

Summary Genetically engineered human pluripotent stem cells (hPSCs) have been proposed as a source for transplantation therapies and are rapidly becoming valuable tools for human disease modeling. However, many applications are limited due to the lack of robust differentiation paradigms that allow for the isolation of defined functional tissues. Here, using an endogenous LGR5-GFP reporter, we derived adult stem cells from hPSCs that gave rise to functional human intestinal tissue comprising all major cell types of the intestine. Histological and functional analyses revealed that such human organoid cultures could be derived with high purity and with a composition and morphology similar to those of cultures obtained from human biopsies. Importantly, hPSC-derived organoids responded to the canonical signaling pathways that control self-renewal and differentiation in the adult human intestinal stem cell compartment. This adult stem cell system provides a platform for studying human intestinal disease in vitro using genetically engineered hPSCs.

Forster, Ryan; Chiba, Kunitoshi; Schaeffer, Lorian; Regalado, Samuel G.; Lai, Christine S.; Gao, Qing; Kiani, Samira; Farin, Henner F.; Clevers, Hans; Cost, Gregory J.; Chan, Andy; Rebar, Edward J.; Urnov, Fyodor D.; Gregory, Philip D.; Pachter, Lior; Jaenisch, Rudolf; Hockemeyer, Dirk

2014-01-01

231

Characterization of monocarboxylate transporter 6: expression in human intestine and transport of the antidiabetic drug nateglinide.  

PubMed

Monocarboxylate transporter (MCT) 6, encoded by SLC16A5, is a member of the monocarboxylate transporter family. Nateglinide, an oral hypoglycemic agent, quickly reaches the maximal serum concentration after its premeal administration. Although the functional existence of uptake systems for nateglinide in the intestine has been demonstrated, these transport systems have not yet been identified at the molecular level. The aim of this study was to demonstrate the localization of MCT6 in the human small intestine and characterize the transport properties of nateglinide via MCT6. Immunohistochemical analysis of the human small intestine revealed that anti-MCT6 antiserum stained the luminal side of the epithelial cells. When expressed in Xenopus laevis oocytes, MCT6-mediated uptake of [(14)C]nateglinide was sensitive to extracellular pH and membrane potential. Furthermore, the K(t) value of nateglinide (45.9 ?M) for MCT6 was lower than those previously reported in Caco-2 cells and rat intestinal brush-border membrane vesicles. In addition, probenecid, fluorescein, valproic acid, and salicylic acid, which are inhibitors of nateglinide uptake in Caco-2 cells and rat intestine, did not inhibit the uptake of nateglinide via MCT6. These results suggest that MCT6 may play a role in the intestinal absorption of nateglinide, although other transporters are also likely involved. PMID:23935065

Kohyama, Noriko; Shiokawa, Hisae; Ohbayashi, Masayuki; Kobayashi, Yasuna; Yamamoto, Toshinori

2013-11-01

232

Defining the critical limit of oxygen extraction in the human small intestine.  

PubMed

Although animal models have been used to characterize the relation between oxygen consumption and blood flow, reliable data have not been generated in the human small intestine. We perfused segments of human small intestine by using an ex vivo perfusion circuit that allowed precise manipulation of blood flow and perfusion pressure. Our goal was to define the critical level of intestinal blood flow necessary to maintain the metabolic needs of the tissue. Human small intestine (n = 5) tissue obtained at transplantation harvest was transported on ice to the laboratory. A 40-cm mid-jejunal segment was selected for perfusion, and appropriate inflow and outflow vessels were identified and cannulated. Perfusion with an autologous blood solution was initiated through an extracorporeal membrane oxygenation circuit. After a 30-minute equilibration period, arterial and venous blood gases were measured at varying flow rates while maintaining a constant hematocrit level. Arterial and venous oxygen content, arteriovenous oxygen difference (A-VO2 diff), and oxygen consumption (VO2) were then calculated. Our results demonstrated that at blood flows > 30 ml/min/100 g, VO2 is independent of blood flow (1.6 +/- 0.06 ml/min/100 g), and oxygen extraction is inversely related to flow. Below this blood flow rate of 30 ml/min/100 g, oxygen extraction does not increase further (6.3 +/- 0.3 vol%), and VO2 becomes flow dependent. This ex vivo preparation defines for the first time a threshold value of blood flow for small intestine below which oxygen consumption decreases (30 ml/min/100 g). Previous animal studies have correlated such a decrease in oxygen consumption with functional and histologic evidence of tissue injury. This "critical" flow rate in human intestine is similar to that found previously in canine and feline intestine, but lower than that of rodent species. PMID:8667504

Desai, T R; Sisley, A C; Brown, S; Gewertz, B L

1996-05-01

233

Detection of Intracellular Bacterial Communities in Human Urinary Tract Infection  

PubMed Central

Background Urinary tract infections (UTIs) are one of the most common bacterial infections and are predominantly caused by uropathogenic Escherichia coli (UPEC). While UTIs are typically considered extracellular infections, it has been recently demonstrated that UPEC bind to, invade, and replicate within the murine bladder urothelium to form intracellular bacterial communities (IBCs). These IBCs dissociate and bacteria flux out of bladder facet cells, some with filamentous morphology, and ultimately establish quiescent intracellular reservoirs that can seed recurrent infection. This IBC pathogenic cycle has not yet been investigated in humans. In this study we sought to determine whether evidence of an IBC pathway could be found in urine specimens from women with acute UTI. Methods and Findings We collected midstream, clean-catch urine specimens from 80 young healthy women with acute uncomplicated cystitis and 20 asymptomatic women with a history of UTI. Investigators were blinded to culture results and clinical history. Samples were analyzed by light microscopy, immunofluorescence, and electron microscopy for evidence of exfoliated IBCs and filamentous bacteria. Evidence of IBCs was found in 14 of 80 (18%) urines from women with UTI. Filamentous bacteria were found in 33 of 80 (41%) urines from women with UTI. None of the 20 urines from the asymptomatic comparative group showed evidence of IBCs or filaments. Filamentous bacteria were present in all 14 of the urines with IBCs compared to 19 (29%) of 66 samples with no evidence of IBCs (p < 0.001). Of 65 urines from patients with E. coli infections, 14 (22%) had evidence of IBCs and 29 (45%) had filamentous bacteria, while none of the gram-positive infections had IBCs or filamentous bacteria. Conclusions The presence of exfoliated IBCs and filamentous bacteria in the urines of women with acute cystitis suggests that the IBC pathogenic pathway characterized in the murine model may occur in humans. The findings support the occurrence of an intracellular bacterial niche in some women with cystitis that may have important implications for UTI recurrence and treatment.

Rosen, David A; Hooton, Thomas M; Stamm, Walter E; Humphrey, Peter A; Hultgren, Scott J

2007-01-01

234

Human Mucosal Associated Invariant T Cells Detect Bacterially Infected Cells  

PubMed Central

Control of infection with Mycobacterium tuberculosis (Mtb) requires Th1-type immunity, of which CD8+ T cells play a unique role. High frequency Mtb-reactive CD8+ T cells are present in both Mtb-infected and uninfected humans. We show by limiting dilution analysis that nonclassically restricted CD8+ T cells are universally present, but predominate in Mtb-uninfected individuals. Interestingly, these Mtb-reactive cells expressed the V?7.2 T-cell receptor (TCR), were restricted by the nonclassical MHC (HLA-Ib) molecule MR1, and were activated in a transporter associated with antigen processing and presentation (TAP) independent manner. These properties are all characteristics of mucosal associated invariant T cells (MAIT), an “innate” T-cell population of previously unknown function. These MAIT cells also detect cells infected with other bacteria. Direct ex vivo analysis demonstrates that Mtb-reactive MAIT cells are decreased in peripheral blood mononuclear cells (PBMCs) from individuals with active tuberculosis, are enriched in human lung, and respond to Mtb-infected MR1-expressing lung epithelial cells. Overall, these findings suggest a generalized role for MAIT cells in the detection of bacterially infected cells, and potentially in the control of bacterial infection.

Gold, Marielle C.; Cerri, Stefania; Smyk-Pearson, Susan; Cansler, Meghan E.; Vogt, Todd M.; Delepine, Jacob; Winata, Ervina; Swarbrick, Gwendolyn M.; Chua, Wei-Jen; Yu, Yik Y. L.; Lantz, Olivier; Cook, Matthew S.; Null, Megan D.; Jacoby, David B.; Harriff, Melanie J.; Lewinsohn, Deborah A.; Hansen, Ted H.; Lewinsohn, David M.

2010-01-01

235

Human cathelicidin LL-37 prevents bacterial biofilm formation.  

PubMed

Human pathogens often colonize their host by the formation of biofilms. These surface-attached aggregates of bacteria are characterized by a self-produced extracellular matrix, which makes them highly resistant towards antibiotic treatment. Their abilities to adhere to abiotic surfaces (e.g., catheters and other medical devices) also makes bacterial biofilm formation a challenge in modern medicine. Antimicrobial peptides have lately been introduced as a potential class of drug molecules for combating severe hospital-acquired infections. One of these peptides, human cathelicidin LL-37, has recently been demonstrated to bridge innate and adaptive host defence, in addition to facilitating a robust antibiofilm effect at sub-inhibitory concentrations. In this review we will discuss the evidence, potential and challenges for LL-37 as a candidate molecule for therapeutic use. PMID:22917247

Jacobsen, Andreas S; Jenssen, Håvard

2012-08-01

236

Growth of human keratinocytes and fibroblasts on bacterial cellulose film.  

PubMed

Thin films of bacterial cellulose (BC) from a nata de coco culture system were developed, characterized, and investigated for the growth of human keratinocytes and fibroblasts. The average pore diameter and total surface area of the dried BC films estimated by BET were 224 A and 12.62 m(2)/g, respectively. With an film thickness of 0.12 mm, the average tensile strength and break strain of the dried films were 5.21 MPa and 3.75%, whereas those of the wet films were 1.56 MPa and 8.00%, respectively. The water absorption capacity of air-dried film was 5.09 g water/g dried films. For uses in the therapy of skin wounds, the potential biological mechanism of action of BC film was evaluated by using human keratinocytes and fibroblasts. Our results were the first direct demonstration that BC film supported the growth, spreading, and migration of human keratinocytes but not those of human fibroblasts. Expressions of E-cadherin and the alpha-3 chain of laminin confirmed the phenotype of human keratinocytes on BC film. PMID:16889398

Sanchavanakit, Neeracha; Sangrungraungroj, Wunwisa; Kaomongkolgit, Ruchadaporn; Banaprasert, Tanom; Pavasant, Prasit; Phisalaphong, Muenduen

2006-01-01

237

Differential expression and function of CYP2C isoforms in human intestine and liver.  

PubMed

This study aimed to characterize the intestinal and hepatic expression and function of CYP2C enzymes in the same set of subjects. CYP2C isoform-specific quantitative reverse transcription-polymerase chain reaction assays, Western immunoblotting and marker reactions of CYP2C8, CYP2C9 and CYP2C19 activities were employed to investigate expression and activity of the CYP2C isoforms in samples of small intestine and liver obtained from 15 patients undergoing gastrectomy or pancreatoduodenectomy. The rank order for CYP2C mRNA expression in the intestine was CYP2C9 = CYP2C18 > CYP2C19 > CYP2C8, whereas that in the liver was CYP2C9 > CYP2C8 > CYP2C18 > CYP2C19. The rank order for expression of CYP2C protein in the intestine was CYP2C9 > CYP2C19 > CYP2C8 (content below limit of quantification) > CYP2C18 (not detected) and that in the liver was CYP2C9 > CYP2C8 > CYP2C19 > CYP2C18 (not detected). The CYP2C9 protein content was approximately 10-fold higher in the liver than in the intestine (P < 0.001). The CLint for the formation of D-703 from verapamil (marker of CYP2C8 activity) was 7.6-fold higher (P < 0.001) and that for the diclofenac 4'-hydroxylation (marker of CYP2C9 activity) was 6.1-fold higher (P < 0.001) in the liver than in the intestine. Apart from a borderline positive correlation (r = 0.58, P = 0.0504) between the intestinal and hepatic CLint for the diclofenac 4'-hydroxylation, no intra-individual relationships between these tissues with respect to expression or activity of different CYP2C isoforms were found. Collectively, these results show that CYP2C8, CYP2C9 and CYP2C19 are expressed as functional enzymes in the human small intestine, and further suggest that CYP2C genes are independently regulated in human intestine and liver. Although, overall, the expression and activity of CYP2C enzymes is lower in the gut than in the liver, the surface area of the proximal small intestine is large and intestinal CYP2C9 and CYP2C19 may well contribute to the first-pass metabolism of their substrate drugs. PMID:12972955

Läpple, Florian; von Richter, Oliver; Fromm, Martin F; Richter, Tanja; Thon, Klaus P; Wisser, Hermann; Griese, Ernst-Ulrich; Eichelbaum, Michel; Kivistö, Kari T

2003-09-01

238

Interactions between the intestinal microbiome and liver diseases.  

PubMed

The human intestine harbors a diverse community of microbes that promote metabolism and digestion in their symbiotic relationship with the host. Disturbance of its homeostasis can result in disease. We review factors that disrupt intestinal homeostasis and contribute to nonalcoholic fatty liver disease, steatohepatitis, alcoholic liver disease, and cirrhosis. Liver disease has long been associated with qualitative and quantitative (overgrowth) dysbiotic changes in the intestinal microbiota. Extrinsic factors, such as the Western diet and alcohol, contribute to these changes. Dysbiosis results in intestinal inflammation, a breakdown of the intestinal barrier, and translocation of microbial products in animal models. However, the contribution of the intestinal microbiome to liver disease goes beyond simple translocation of bacterial products that promote hepatic injury and inflammation. Microbial metabolites produced in a dysbiotic intestinal environment and host factors are equally important in the pathogenesis of liver disease. We review how the combination of liver insult and disruptions in intestinal homeostasis contribute to liver disease. PMID:24440671

Schnabl, Bernd; Brenner, David A

2014-05-01

239

Detection and Characterization of Hemopoietic Stem Cells in the Adult Human Small Intestine1  

Microsoft Academic Search

The concept of lymphoid differentiation in the human gastrointestinal tract is controversial but is the focus of this study, which examined adult human small intestinal tissue for the presence of CD34CD45 hemopoietic stem cells (HSCs) and lymphoid progenitors. Flow cytometry demonstrated that over 5% of leukocytes (CD45 cells) isolated from human gut were HSCs coex- pressing CD34, a significantly higher

Lydia Lynch; Diarmuid O'Donoghue; Jonathan Dean; Jacintha O'Sullivan; Cliona O'Farrelly; Lucy Golden-Mason

240

Similarity of hydrolyzing activity of human and rat small intestinal disaccharidases  

PubMed Central

Background: The purpose of this study was to clarify whether it is possible to extrapolate results from studies of the hydrolyzing activity of disaccharidases from rats to humans. Materials and methods: We measured disaccharidase activity in humans and rats using identical preparation and assay methods, and investigated the similarity in hydrolyzing activity. Small intestinal samples without malignancy were donated by five patients who had undergone bladder tumor surgery, and homogenates were prepared to measure disaccharidase activity. Adult rat homogenates were prepared using small intestine. Results: Maltase activity was the highest among the five disaccharidases, followed by sucrase and then palatinase in humans and rats. Trehalase activity was slightly lower than that of palatinase in humans and was similar to that of sucrase in rats. Lactase activity was the lowest in humans, but was similar to that of palatinase in rats. Thus, the hydrolyzing activity of five disaccharidases was generally similar in humans and rats. The relative activity of sucrose and palatinase versus maltase was generally similar between humans and rats. The ratio of rat to human hydrolyzing activity of maltase, sucrase, and palatinase was 1.9–3.1, but this was not a significant difference. Leaf extract from Morus alba strongly inhibited the activity of maltase, sucrase, and palatinase, but not trehalase and lactase, and the degree of inhibition was similar in humans and rats. L-arabinose mildly inhibited sucrase activity, but hardly inhibited the activity of maltase, palatinase, trehalase and lactase in humans and rats. The digestibility of 1-kestose, galactosylsucrose, and panose by small intestinal enzymes was very similar between humans and rats. Conclusion: These results demonstrate that the digestibility of newly developed saccharide materials evaluated by rat small intestinal enzymes can substitute for evaluation using human enzymes.

Oku, Tsuneyuki; Tanabe, Kenichi; Ogawa, Shigeharu; Sadamori, Naoki; Nakamura, Sadako

2011-01-01

241

Human Oral Isolate Lactobacillus fermentum AGR1487 Reduces Intestinal Barrier Integrity by Increasing the Turnover of Microtubules in Caco-2 Cells  

PubMed Central

Lactobacillus fermentum is found in fermented foods and thought to be harmless. In vivo and clinical studies indicate that some L. fermentum strains have beneficial properties, particularly for gastrointestinal health. However, L. fermentum AGR1487 decreases trans-epithelial electrical resistance (TEER), a measure of intestinal barrier integrity. The hypothesis was that L. fermentum AGR1487 decreases the expression of intestinal cell tight junction genes and proteins, thereby reducing barrier integrity. Transcriptomic and proteomic analyses of Caco-2 cells (model of human intestinal epithelial cells) treated with L. fermentum AGR1487 were used to obtain a global view of the effect of the bacterium on intestinal epithelial cells. Specific functional characteristics by which L. fermentum AGR1487 reduces intestinal barrier integrity were examined using confocal microscopy, cell cycle progression and adherence bioassays. The effects of TEER-enhancing L. fermentum AGR1485 were investigated for comparison. L. fermentum AGR1487 did not alter the expression of Caco-2 cell tight junction genes (compared to L. fermentum AGR1485) and tight junction proteins were not able to be detected. However, L. fermentum AGR1487 increased the expression levels of seven tubulin genes and the abundance of three microtubule-associated proteins, which have been linked to tight junction disassembly. Additionally, Caco-2 cells treated with L. fermentum AGR1487 did not have defined and uniform borders of zona occludens 2 around each cell, unlike control or AGR1485 treated cells. L. fermentum AGR1487 cells were required for the negative effect on barrier integrity (bacterial supernatant did not cause a decrease in TEER), suggesting that a physical interaction may be necessary. Increased adherence of L. fermentum AGR1487 to Caco-2 cells (compared to L. fermentum AGR1485) was likely to facilitate this cell-to-cell interaction. These findings illustrate that bacterial strains of the same species can cause contrasting host responses and suggest that food-safe status should be given to individual strains not species.

Anderson, Rachel C.; Young, Wayne; Clerens, Stefan; Cookson, Adrian L.; McCann, Mark J.; Armstrong, Kelly M.; Roy, Nicole C.

2013-01-01

242

Neonatal Necrotizing Enterocolitis -Inflammation and Intestinal Immaturity  

PubMed Central

Neonatal necrotizing enterocolitis is a devastating inflammatory bowel disease of premature infants. The pathogenesis remains incompletely understood and there is no specific treatment. Efforts are ongoing to understand aspects of intestinal immaturity which contribute to susceptibility to this disease. This review focuses on bacterial colonization patterns, intestinal barrier function, and inflammatory responses of immature enterocytes leading to a unique vulnerability of the preterm gut. In addition the possible therapeutic potential of factors in human milk and probiotic bacteria is discussed.

Claud, Erika C.

2010-01-01

243

Dietary interactions with the bacterial sensing machinery in the intestine: the plant polyphenol case  

PubMed Central

There are millions of microbes that live in the human gut. These are important in digestion as well as defense. The host immune system needs to be able to distinguish between the harmless bacteria and pathogens. The initial interaction between bacteria and the host happen through the pattern recognition receptors (PRRs). As these receptors are in direct contact with the external environment, this makes them important candidates for regulation by dietary components and therefore potential targets for therapy. In this review, we introduce some of the main PRRs including a cellular process known as autophagy, and how they function. Additionally we review dietary phytochemicals from plants which are believed to be beneficial for humans. The purpose of this review was to give a better understanding of how these components work in order to create better awareness on how they could be explored in the future.

Ahmed Nasef, Noha; Mehta, Sunali; Ferguson, Lynnette R.

2014-01-01

244

The dietary histone deacetylase inhibitor sulforaphane induces human ?-defensin-2 in intestinal epithelial cells  

PubMed Central

Antimicrobial peptides like human ?-defensin-2 (HBD-2) play an important role in the innate immune system protecting the intestinal mucosa against bacterial invasion. The dietary histone deacetylase (HDAC) inhibitors sulforaphane (SFN) and butyrate have received a great deal of attention because of their ability to simultaneously modulate multiple cellular targets involved in cellular protection. In this study the influence of SFN and butyrate on HBD-2 expression as well as the molecular pathways involved in SFN-mediated induction of HBD-2 were scrutinized. Treatment of Caco-2, HT-29 and SW480 cells with SFN led to a time- and dose-dependent upregulation of HBD-2 mRNA expression as determined by semi-quantitative reverse transcription–polymerase chain reaction. Moreover, HBD-2 protein production increased in response to SFN, measured by enzyme-linked immunosorbent assay. Induction of HBD-2 was also observed in response to butyrate. Immunofluorescence analysis revealed that the protein was localized in the cytosol. Coincubation of SFN with a vitamin D receptor (VDR), or an extracellular-regulated kinase 1/2 or a nuclear factor-?B inhibitor all reduced HBD-2 mRNA upregulation. In contrast, transfection of cells with a dominant-negative peroxisome proliferator-activated receptor ? (PPAR?) mutant vector to inhibit PPAR? wild-type action and inhibition of p38 mitogen-activated protein kinase (MAPK) signalling did not affect SFN-mediated upregulation of HBD-2 mRNA. Moreover, SFN induced the expression of VDR, PPAR? and phosphorylated ERK1/2 but did not affect p38 MAPK activation. The data clearly demonstrate for the first time that the dietary HDAC inhibitor SFN is able to induce antimicrobial peptides in colonocytes. In this process HBD-2 expression is regulated via VDR, mitogen-activated protein kinase kinase/extracellular-regulated kinase and nuclear factor-?B signalling.

Schwab, Markus; Reynders, Veerle; Loitsch, Stefan; Steinhilber, Dieter; Schroder, Oliver; Stein, Jurgen

2008-01-01

245

Identification of an intestine-specific promoter and inducible expression of bacterial ?-galactosidase in mammalian cells by a lac operon system  

PubMed Central

Background ?-galactosidase has been widely used in animal husbandry to reduce anti-nutritional factors (such as ?-galactoside) in feed. Intestine-specific and substrate inducible expression of ?-galactosidase would be highly beneficial for transgenic animal production. Methods To achieve the intestine-specific and substrate inducible expression of ?-galactosidase, we first identified intestine-specific promoters by comparing the transcriptional activity and tissue specificity of four intestine-specific promoters from human intestinal fatty acid binding protein, rat intestinal fatty acid binding protein, human mucin-2 and human lysozyme. We made two chimeric constructs combining the promoter and enhancer of human mucin-2, rat intestinal trefoil factor and human sucrase-isomaltase. Then a modified lac operon system was constructed to investigate the induction of ?-galactosidase expression and enzyme activity by isopropyl ?-D-1-thiogalactopyranoside (IPTG) and an ?-galactosidase substrate, ?-lactose. We declared that the research carried out on human (Zhai Yafeng) was in compliance with the Helsinki Declaration, and experimental research on animals also followed internationally recognized guidelines. Results The activity of the human mucin-2 promoter was about 2 to 3 times higher than that of other intestine-specific promoters. In the lac operon system, the repressor significantly decreased (P < 0.05) luciferase activity by approximately 6.5-fold and reduced the percentage of cells expressing green fluorescent protein (GFP) by approximately 2-fold. In addition, the expression level of ?-galactosidase mRNA was decreased by 6-fold and ?-galactosidase activity was reduced by 8-fold. In line with our expectations, IPTG and ?-lactose supplementation reversed (P < 0.05) the inhibition and produced a 5-fold increase of luciferase activity, an 11-fold enhancement in the percentage of cells with GFP expression and an increase in ?-galactosidase mRNA abundance (by about 5-fold) and ?-galactosidase activity (by about 7-fold). Conclusions We have successfully constructed a high specificity inducible lac operon system in an intestine-derived cell line, which could be of great value for gene therapy applications and transgenic animal production.

2012-01-01

246

A review of drug solubility in human intestinal fluids: implications for the prediction of oral absorption.  

PubMed

The purpose of this paper is to collate all recently published solubility data of orally administered drugs in human intestinal fluids (HIF) that were aspirated from the upper small intestine (duodenum and jejunum). The data set comprises in total 102 solubility values in fasted state HIF and 37 solubility values in fed state HIF, covering 59 different drugs. Despite differences in the protocol for HIF sampling and subsequent handling, this summary of HIF solubilities provides a critical reference data set to judge the value of simulated media for intestinal solubility estimation. In this regard, the review includes correlations between the reported solubilizing capacity of HIF and fasted or fed state simulated intestinal fluid (FaSSIF/FeSSIF). Correlating with HIF solubilities enables the optimal use of solubility measurements in simulated biorelevant media to obtain accurate estimates of intestinal solubility during drug development. Considering the fraction of poorly soluble new molecular entities in contemporary drug discovery, adequate prediction of intestinal solubility is critical for efficient lead optimization, early candidate profiling, and further development. PMID:23994640

Augustijns, Patrick; Wuyts, Benjamin; Hens, Bart; Annaert, Pieter; Butler, James; Brouwers, Joachim

2014-06-16

247

Heparan sulfate and syndecan-1 are essential in maintaining murine and human intestinal epithelial barrier function  

PubMed Central

Patients with protein-losing enteropathy (PLE) fail to maintain intestinal epithelial barrier function and develop an excessive and potentially fatal efflux of plasma proteins. PLE occurs in ostensibly unrelated diseases, but emerging commonalities in clinical observations recently led us to identify key players in PLE pathogenesis. These include elevated IFN-?, TNF-?, venous hypertension, and the specific loss of heparan sulfate proteoglycans from the basolateral surface of intestinal epithelial cells during PLE episodes. Here we show that heparan sulfate and syndecan-1, the predominant intestinal epithelial heparan sulfate proteoglycan, are essential in maintaining intestinal epithelial barrier function. Heparan sulfate– or syndecan-1–deficient mice and mice with intestinal-specific loss of heparan sulfate had increased basal protein leakage and were far more susceptible to protein loss induced by combinations of IFN-?, TNF-?, and increased venous pressure. Similarly, knockdown of syndecan-1 in human epithelial cells resulted in increased basal and cytokine-induced protein leakage. Clinical application of heparin has been known to alleviate PLE in some patients but its unknown mechanism and severe side effects due to its anticoagulant activity limit its usefulness. We demonstrate here that non-anticoagulant 2,3-de-O-sulfated heparin could prevent intestinal protein leakage in syndecan-deficient mice, suggesting that this may be a safe and effective therapy for PLE patients.

Bode, Lars; Salvestrini, Camilla; Park, Pyong Woo; Li, Jin-Ping; Esko, Jeffrey D.; Yamaguchi, Yu; Murch, Simon; Freeze, Hudson H.

2007-01-01

248

Secretion of human intestinal angiotensin-converting enzyme and its association with the differentiation state of intestinal cells.  

PubMed Central

Human angiotensin I-converting enzyme (ACE) exists in intestinal epithelial cells as a membrane-bound (ACEm) and secretory glycoprotein (ACEsec). The electrophoretic mobilities of ACEsec and ACEm on SDS/polyacrylamide gels are similar; the N-deglycosylated ACEsec and ACEm, in contrast, display slight differences in their apparent molecular masses, indicating that the carbohydrate contents of ACEsec and ACEm are different. Moreover, ACEsec is solely N-glycosylated whereas ACEm is N- and O-glycosylated, assessed by lectin binding studies. Spontaneous release of ACEsec is achieved by incubation of brush border membranes at 37 degrees C. Aprotinin, leupeptin and EDTA partly inhibit the generation of ACEsec, strongly suggesting that ACEsec is generated from ACEm by proteolytic cleavage. The expression levels of ACEsec in the intestine may be associated with the differentiation state of mucosal cells. Thus ACEsec is more abundant than ACEm in immature non-epithelial crypt cells of patients with coeliac disease. Well-differentiated epithelial cells, by contrast, contain predominantly ACEm. The variations in the proportions of cleaved ACEsec in differentiated and non-differentiated cells may be due to varying levels of the cleaving protease. Alternatively, because epithelial cell differentiation is accompanied by alterations in the levels of oligosaccharyltransferases, the results suggest a critical role for the glycosylation pattern of ACEm in its susceptibility to the putative cleaving protease.

Naim, H Y

1996-01-01

249

Identification of the transcriptional response of human intestinal mucosa to Lactobacillus plantarum WCFS1 in vivo  

PubMed Central

Background There is limited knowledge on the extent and dynamics of the mucosal response to commensal and probiotic species in the human intestinal lumen. This study aimed to identify the acute, time-dependent responses of intestinal mucosa to commensal Lactobacillus plantarum WCFS1 in vivo in two placebo-controlled human intervention studies in healthy volunteers. Transcriptional changes in duodenal mucosa upon continuous intraduodenal infusion of L. plantarum WCFS1 for one- and six h, respectively, were studied using oro- and nasogastric intubations with dedicated orogastric catheters and tissue sampling by standard flexible gastroduodenoscopy. Results One- and six-h exposure of small intestinal mucosa to L. plantarum WCFS1 induced differential expression of 669 and 424 gene reporters, respectively. While short-term exposure to L. plantarum WCFS1 inhibited fatty acid metabolism and cell cycle progression, cells switched to a more proliferative phase after prolonged exposure with an overall expression profile characterized by upregulation of genes involved in lipid metabolism, cellular growth and development. Cell death and immune responses were triggered, but cell death-executing genes or inflammatory signals were not expressed. Proteome analysis showed differential expression of several proteins. Only the microsomal protein 'microsomal triglyceride transfer protein' was regulated on both the transcriptional and the protein level in all subjects. Conclusion Overall, this study showed that intestinal exposure to L. plantarum WCFS1 induced consistent, time-dependent transcriptional responses in healthy intestinal mucosa. This extensive exploration of the human response to L. plantarum WCFS1 could eventually provide molecular support for specific or probiotic activity of this strain or species, and exemplifies the strength of the applied technology to identify the potential bio-activity of microbes in the human intestine.

Troost, Freddy J; van Baarlen, Peter; Lindsey, Patrick; Kodde, Andrea; de Vos, Willem M; Kleerebezem, Michiel; Brummer, Robert-Jan M

2008-01-01

250

Bacterial delivery of TALEN proteins for human genome editing.  

PubMed

Transcription Activator-Like Effector Nucleases (TALENs) are a novel class of sequence-specific nucleases that have recently gained prominence for its ease of production and high efficiency in genome editing. A TALEN pair recognizes specific DNA sequences and introduce double-strand break in the target site, triggering non-homologous end joining and homologous recombination. Current methods of TALEN delivery involves introduction of foreign genetic materials, such as plasmid DNA or mRNA, through transfection. Here, we show an alternative way of TALEN delivery, bacterial type III secretion system (T3SS) mediated direct injection of the TALEN proteins into human cells. Bacterially injected TALEN was shown to efficiently target host cell nucleus where it persists for almost 12 hours. Using a pair of TALENs targeting venus gene, such injected nuclear TALENs were shown functional in introducing DNA mutation in the target site. Interestingly, S-phase cells seem to show greater sensitivity to the TALEN mediated target gene modification. Accordingly, efficiency of such genome editing can easily be manipulated by the infection dose, number of repeated infections as well as enrichment of S phase cells. This work further extends the utility of T3SS in the delivery of functional proteins into mammalian cells to alter their characters for biomedical applications. PMID:24618838

Jia, Jingyue; Jin, Yongxin; Bian, Ting; Wu, Donghai; Yang, Lijun; Terada, Naohiro; Wu, Weihui; Jin, Shouguang

2014-01-01

251

Bacterial Delivery of TALEN Proteins for Human Genome Editing  

PubMed Central

Transcription Activator-Like Effector Nucleases (TALENs) are a novel class of sequence-specific nucleases that have recently gained prominence for its ease of production and high efficiency in genome editing. A TALEN pair recognizes specific DNA sequences and introduce double-strand break in the target site, triggering non-homologous end joining and homologous recombination. Current methods of TALEN delivery involves introduction of foreign genetic materials, such as plasmid DNA or mRNA, through transfection. Here, we show an alternative way of TALEN delivery, bacterial type III secretion system (T3SS) mediated direct injection of the TALEN proteins into human cells. Bacterially injected TALEN was shown to efficiently target host cell nucleus where it persists for almost 12 hours. Using a pair of TALENs targeting venus gene, such injected nuclear TALENs were shown functional in introducing DNA mutation in the target site. Interestingly, S-phase cells seem to show greater sensitivity to the TALEN mediated target gene modification. Accordingly, efficiency of such genome editing can easily be manipulated by the infection dose, number of repeated infections as well as enrichment of S phase cells. This work further extends the utility of T3SS in the delivery of functional proteins into mammalian cells to alter their characters for biomedical applications.

Bian, Ting; Wu, Donghai; Yang, Lijun; Terada, Naohiro; Wu, Weihui; Jin, Shouguang

2014-01-01

252

Human intestinal trefoil factor is expressed in human hypothalamus and pituitary: evidence for a novel neuropeptide.  

PubMed

Human intestinal trefoil factor, hITF, a secretory polypeptide found mainly in the human gastrointestinal tract, is a member of the newly characterized trefoil factor or P-domain peptide family representing putative growth factors. Here we describe the identification of this gut peptide in the human brain and pituitary. With reverse transcriptase polymerase chain reaction, we were able to isolate and clone the transcript from human hypothalamus. An antibody generated against a synthetic peptide derived from the carboxyl terminus of hITF was used for immunohistochemical studies of appropriate tissue sections. Neurons expressing hITF were identified in two magnocellular hypothalamic nuclei, the paraventricular and periventricular nuclei. hITF polypeptide was also observed in Herring bodies of the neurohypophysis and in secretory cells of the adenohypophysis. Double immunostaining with antigrowth hormone antibody showed partial coexistence in a selected subpopulation of adenohypophysial cells. Localization of hITF in the hypothalamo-neurohypophysial system may suggest a modulatory action on the classical magnocellular nonapeptides vasopressin and oxytocin, and further indicates an adenohypophysial importance of this peptide. It is likely that hITF represents a novel neuropeptide of yet unknown function. PMID:8940297

Probst, J C; Zetzsche, T; Weber, M; Theilemann, P; Skutella, T; Landgraf, R; Jirikowski, G F

1996-11-01

253

Bacterial transfer of large functional genomic DNA into human cells.  

PubMed

Efficient transfer of chromosome-based vectors into mammalian cells is difficult, mostly due to their large size. Using a genetically engineered invasive Escherichia coli vector, alpha satellite DNA cloned in P1-based artificial chromosome was stably delivered into the HT1080 cell line and efficiently generated human artificial chromosomes de novo. Similarly, a large genomic cystic fibrosis transmembrane conductance regulator (CFTR) construct of 160 kb containing a portion of the CFTR gene was stably propagated in the bacterial vector and transferred into HT1080 cells where it was transcribed, and correctly spliced, indicating transfer of an intact and functional locus of at least 80 kb. These results demonstrate that bacteria allow the cloning, propagation and transfer of large intact and functional genomic DNA fragments and their subsequent direct delivery into cells for functional analysis. Such an approach opens new perspectives for gene therapy. PMID:15973438

Laner, A; Goussard, S; Ramalho, A S; Schwarz, T; Amaral, M D; Courvalin, P; Schindelhauer, D; Grillot-Courvalin, C

2005-11-01

254

In vitro intestinal and hepatic metabolism of Di(2-ethylhexyl) phthalate (DEHP) in human and rat.  

PubMed

Species and organ differences in the intrinsic clearance and the enzymes involved in the metabolism of DEHP were examined in subcellular fractions of the intestine and liver as well as by recombinant cytochrome P450 (CYP) isoforms of human and rat. Estimated clearance (CLint) of DEHP via esterase-mediated pathway in human intestine was 2.4-fold greater than that in human liver while its value in rat intestine was 1.7-fold less than that in rat liver. Ranks of CLint for CYP-mediated oxidation/dealkylation of MEHP were human liver>rat liver>human intestine>rat intestine. Estimates of CLint for the production of mono(2-ethyl-5-hydroxyhexyl) phthalate and mono(2-ethyl-5-oxohexyl) phthalate by human CYP2C9 1 were 4.2- and 2.6-fold greater than those by rat CYP2C6, respectively. Total CLint via hCYP2C9 3-mediated oxidation was 1.9- and 2.6-fold less than those by hCYP2C9 2 and 2C9 1, respectively. Estimated CLint for phthalic acid production by hCYP3A4 was 24.5 ?L nmol CYP(-1)min(-1) while it was continuously produced by rCYP2C6 and 3A2 via passive mechanism. These species/organ differences in major metabolic pathway and CYP isoforms should be considered for appraisal of the potential adverse health effects of DEHP. PMID:23545481

Choi, Kyoungju; Joo, Hyun; Campbell, Jerry L; Andersen, Melvin E; Clewell, Harvey J

2013-08-01

255

Intestinal lipids and lipoproteins in the human fetus: modulation by epidermal growth factor  

Microsoft Academic Search

The aim of the present investigation was first, to ex- amine the ability of human fetal intestine (17-20 wk) to incorpo- rate fatty acid into esterified lipids; and second, to study in vitro lipoprotein synthesis and secretion by fetal explants, as well as the effect of epidermal growth factor (EGF) on these processes. Cultured fetal jejunal explants were incubated in

Emile Levy; Louise Thibault; HBpital Ste-Justine

256

In vitro investigations of the effect of probiotics and prebiotics on selected human intestinal pathogens  

Microsoft Academic Search

This study investigated the effects of selected probiotic microorganisms, in combination with prebiotics, on certain human intestinal food-borne pathogens. Probiotics grown with different carbohydrate sources were observed to inhibit growth of Escherichia coli, Campylobacter jejuni and Salmonella enteritidis, with the extent of inhibition varying according to the carbohydrate source provided. Prebiotics identified as being preferentially utilised by the probiotics tested

Laura J Fooks; Glenn R Gibson

2002-01-01

257

Smooth muscle expresses bone morphogenetic protein (Vgr-1/BMP-6) in human fetal intestine.  

PubMed

During human fetal development, autocrine TGF-beta1 regulates the synthesis of specific collagen types by intestinal smooth muscle cells in an age-dependent manner. Vgr-1/BMP6, a member of the TGF-beta superfamily, modulates epithelial, endochondral and neural tissue development in mice: a related peptide is essential to gut morphogenesis in Drosophila. This is the first study to detect vgr-1/BMP-6 during human intestinal organogenesis. Polyclonal antibodies to the precursor and mature fragments of vgr-1 were used in immunohistochemical studies of human intestine at 15, 19 and 24 weeks' gestation. Immunoreactivity was detected with the antibody directed against the precursor portion of vgr-1. Only smooth muscle structures stained for vgr-1 including muscularis propria, muscularis mucosa and vasculature. BMP-6 mRNA was detected by RNase protection assay in cultured muscle cells from 11, 17 and 22 weeks' gestation. This study demonstrates vgr-1/BMP 6 expression in the developing human fetal intestine, exclusively in muscle. PMID:9925908

Perr, H A; Ye, J; Gitelman, S E

1999-03-01

258

Comparative analysis of the genomes of intestinal spirochetes of human and animal origin.  

PubMed Central

The aim of the present work was to compare the genomes of 21 strains of intestinal spirochetes, which were isolated from patients suffering intestinal disorders, with those of Treponema hyodysenteriae (strain P18), the known etiological agent of swine dysentery (bloody scours), and of a nonpathogenic strain (M1) of Treponema innocens. The percent guanine-plus-cytosine value of the 23 DNAs was found to be 25.5 to 30.1, as determined by a double-labeling procedure based on nick-translation by DNA polymerase I. The genome size of two spirochetal strains, of human and porcine origin, was found to be similar (4 x 10(6) base pairs) and close to that of the reference bacterium Escherichia coli (4.2 x 10(6) base pairs). Restriction analysis showed the presence of two modified bases in spirochetal DNA. Methyladenine was present in the GATC sequence of DNA from 15 spirochetes of human origin, and methylcytosine was present in several sequences occurring in all strains. The DNA of T. hyodysenteriae displayed a 30 to 100% homology with respect to that of 21 spirochetes from humans, thus suggesting the occurrence of a genetic heterogeneity in the latter group. These data indicate that the intestinal spirochetes analyzed in the present work are related; hence there is a possibility of domestic animals being reservoirs of microorganisms pathogenic for humans. A classification of intestinal treponemes into subgroups has been proposed on the basis of restriction analysis and hybridization experiments. Images

Coene, M; Agliano, A M; Paques, A T; Cattani, P; Dettori, G; Sanna, A; Cocito, C

1989-01-01

259

Consensus hologram QSAR modeling for the prediction of human intestinal absorption.  

PubMed

Consistent in silico models for ADME properties are useful tools in early drug discovery. Here, we report the hologram QSAR modeling of human intestinal absorption using a dataset of 638 compounds with experimental data associated. The final validated models are consistent and robust for the consensus prediction of this important pharmacokinetic property and are suitable for virtual screening applications. PMID:22425566

Moda, Tiago L; Andricopulo, Adriano D

2012-04-15

260

Environmental contaminants and intestinal function  

PubMed Central

The environmental contaminants which have their major effects on the small intestine may be classified into five major categories: (1) bacterial, viral, and parasitic agents, (2) food and plant substances, (3) environmental and industrial products, (4) pharmaceutical agents, and (5) toxic agents whose metabolic effects are dependent on interreaction with intestinal bacterial flora, other physical agents (detergents), human intestinal enzyme deficiency states, and the nutritional state of the host. Bacterial, viral, and parasitic agents are the most important of all such agents, being responsible for significant mortality and morbidity in association with diarrheal diseases of adults and children. Several plant substances ingested as foods have unique effects on the small bowel as well as from contaminants such as fungi on poorly preserved grains and cereals. Environmental and industrial products, in spite of their widespread prevalence in industrial societies as contaminants, are less important unless unexpectedly intense exposure occurs to the intestinal tract. Pharmaceutical agents of several types interreact with the small bowel mucosa causing impairment of transport processes for fluid and electrolytes, amino acid, lipid and sugars as well as vitamins. These interreactions may be dependent on bacterial metabolic activity, association with detergents, mucosal enzyme deficiency state (disaccharidases), and the state of nutrition of the subject.

Banwell, John G.

1979-01-01

261

Intestinal transport of manganese from human milk, bovine milk and infant formula in rats  

SciTech Connect

The transport of manganese from extrinsically labeled human milk, bovine milk and infant formula was studied by the everted intestinal sac method. Tissue/mucosal flux data indicated that transport of manganese into the intestinal tissue was significantly greater with bovine milk and formula than from human milk. Similarly, the total flux of manganese from the mucosal to serosal surface was less when human milk was used. Smaller molecular weight manganese binding ligands isolated from the milk samples enhanced the mucosal to tissue movement of manganese as contrasted to the higher molecular weight manganese binding ligands. Most significantly the data suggest that the transport and uptake of manganese is less in the presence of human milk and its isolated manganese fractions than it is in bovine milk or infant formula. 15 references, 3 tables.

Chan, W.Y.; Bates, J.M. Jr.; Rennert, O.M.; Mahmood, A.; Torres-Pinedo, R.

1984-12-10

262

Transport of Quercetin and Its Glucosides across Human Intestinal Epithelial Caco-2 Cells  

Microsoft Academic Search

There is mounting evidence from human epidemiological, animal in vivo, and in vitro studies to suggest beneficial effects related to the consumption of quercetin and its glucosides. However, there is limited knowledge on the oral bioavailability of these natural products. This study examined the intestinal epithelial membrane transport of quercetin, quercetin 4?-glucoside, and quercetin 3,4?-diglucoside, using the Caco-2 human colonic

Richard A Walgren; U. Kristina Walle; Thomas Walle

1998-01-01

263

Th2 Cytokines Down-Regulate TLR Expression and Function in Human Intestinal Epithelial Cells1  

Microsoft Academic Search

TLRs serve important immune and nonimmune functions in human intestinal epithelial cells (IECs). Proinflammatory Th1 cytokines have been shown to promote TLR expression and function in IECs, but the effect of key Th2 cytokines (IL-4, IL-5, IL-13) on TLR signaling in IECs has not been elucidated so far. We stimulated human model IECs with Th2 cytokines and examined TLR mRNA

Tobias Mueller; Tomohiro Terada; Ian M. Rosenberg; Oren Shibolet; Daniel K. Podolsky

264

Human intestinal water absorption: direct vs. indirect measurements.  

PubMed

Distilled water, a carbohydrate-electrolyte (CE; 4% sucrose, 2% glucose, 17.2 meq/l NaCl, and 2.8 meq/l KCl) solution, or a 10% glucose solution, all containing the nonabsorbed indicator polyethylene glycol (PEG) and deuterium oxide (D2O, 30 ppm), were infused (15 ml/min) into the duodenojejunum of seven men by using the triple lumen technique. Net water absorption was determined directly from the change in PEG concentration and was calculated from plasma D2O derived from D2O in the perfusion solutions. The protocol included a 45-min equilibration period followed by a 90-min test period. Intestinal samples were drawn at 10-min intervals from 15 to 45 min and at 15-min intervals thereafter. Blood was drawn at 45, 50, 55, 60, 75, 90, 105, 120, and 135 min. Intestinal samples were analyzed for D2O, Na+, K+, osmolality, PEG, and glucose; blood was analyzed for D2O. Results (+/- SE; positive values secretion, negative values absorption) showed net fluid absorption from distilled water (-9.40 +/- 1.28 ml.h-1.cm-1) and the CE (-13.30 +/- 1.22 ml.h-1.cm-1) solution, but net secretion (4.40 +/- 1.25 ml.h-1.cm-1) from the 10% glucose solution. All values were significantly (P less than 0.05) different from each other. Perfusing the CE solution caused net Na+ and K+ absorption, whereas perfusing the 10% dextrose solution caused net electrolyte secretion. Rates of D2O accumulation in the plasma were independent of the solutions perfused.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2305887

Gisolfi, C V; Summers, R W; Schedl, H P; Bleiler, T L; Oppliger, R A

1990-02-01

265

5-Hydroxytryptamine and human small intestinal motility: effect of inhibiting 5-hydroxytryptamine reuptake.  

PubMed Central

Parenteral 5-hydroxytryptamine stimulates small intestinal motility, but the effect of continuous stimulation with 5-hydroxytryptamine on the human migrating motor complex is unknown. Using a selective 5-hydroxytryptamine reuptake inhibitor, paroxetine, this study investigated the effect of indirect 5-hydroxytryptamine agonism on fasting small intestinal motility and transit. Eight healthy subjects were studied while receiving paroxetine 30 mg daily for five days and while receiving no treatment, in random order. Ambulant small intestinal motility was recorded from five sensors positioned from the duodenojejunal flexure to the ileum for 16-18 hours. Paroxetine reduced the migrating motor complex periodicity mean (SEM) from 81 (6) min to 67 (4) min (p < 0.05), and increased the propagation velocity of phase III from 3.1 to 4.7 cm/min in the proximal jejunum (p < 0.01), and from 1.6 to 3.4 cm/min distally (p < 0.001). Orocaecal transit time measured by lactulose hydrogen breath test was reduced by paroxetine from 70 (9) min to 48 (7) min (p < 0.05). These data suggest that 5-hydroxytryptamine participates in the control of migrating motor complexes in humans, and that selective 5-hydroxytryptamine reuptake inhibitors have a prokinetic action in the human small intestine.

Gorard, D A; Libby, G W; Farthing, M J

1994-01-01

266

Exploring the Diversity of the Bifidobacterial Population in the Human Intestinal Tract?  

PubMed Central

Although the health-promoting roles of bifidobacteria are widely accepted, the diversity of bifidobacteria among the human intestinal microbiota is still poorly understood. We performed a census of bifidobacterial populations from human intestinal mucosal and fecal samples by plating them on selective medium, coupled with molecular analysis of selected rRNA gene sequences (16S rRNA gene and internally transcribed spacer [ITS] 16S-23S spacer sequences) of isolated colonies. A total of 900 isolates were collected, of which 704 were shown to belong to bifidobacteria. Analyses showed that the culturable bifidobacterial population from intestinal and fecal samples include six main phylogenetic taxa, i.e., Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis, Bifidobacterium pseudolongum, Bifidobacterium breve, and Bifidobacterium bifidum, and two species mostly detected in fecal samples, i.e., Bifidobacterium dentium and Bifidobacterium animalis subp. lactis. Analysis of bifidobacterial distribution based on age of the subject revealed that certain identified bifidobacterial species were exclusively present in the adult human gut microbiota whereas others were found to be widely distributed. We encountered significant intersubject variability and composition differences between fecal and mucosa-adherent bifidobacterial communities. In contrast, a modest diversification of bifidobacterial populations was noticed between different intestinal regions within the same individual (intrasubject variability). Notably, a small number of bifidobacterial isolates were shown to display a wide ecological distribution, thus suggesting that they possess a broad colonization capacity.

Turroni, Francesca; Foroni, Elena; Pizzetti, Paola; Giubellini, Vanessa; Ribbera, Angela; Merusi, Paolo; Cagnasso, Patrizio; Bizzarri, Barbara; de'Angelis, Gian Luigi; Shanahan, Fergus; van Sinderen, Douwe; Ventura, Marco

2009-01-01

267

Human milk oligosaccharides influence maturation of human intestinal Caco-2Bbe and HT-29 cell lines.  

PubMed

Stimulation of gastrointestinal tract maturation is 1 of the many benefits of human milk. Human milk oligosaccharides (HMOs) are abundant in human milk and are reported to promote enterocyte differentiation in vitro. The objective of this study was to assess the impact of 3 predominant HMOs on multiple aspects of enterocyte maturation in vitro. Ranging from crypt-like to differentiated enterocytes, we used the well-characterized intestinal cell lines HT-29 and Caco-2Bbe to model early and late stages of differentiation, respectively. With this model of the crypt-villus axis made up of preconfluent HT-29, preconfluent Caco-2Bbe, and postconfluent Caco-2Bbe cultures, we characterized the impact of lacto-N-neotetraose (LNnT), 2'-fucosyllactose (2'FL), and 6'-sialyllactose on epithelial cell kinetics and function. All 3 HMOs dose-dependently inhibited cell proliferation in undifferentiated HT-29 and Caco-2Bbe cultures (P < 0.05). In contrast to previous reports, only treatment with 2'FL at concentrations similar to human milk increased alkaline phosphatase activity by 31% (P = 0.044) in HT-29 cultures and increased sucrase activity by 54% (P = 0.005) in well-differentiated Caco-2Bbe cultures. LNnT at concentrations similar to that reported for human milk increased transepithelial resistance by 21% (P = 0.002) in well-differentiated Caco-2Bbe cells. In summary, all 3 HMOs reduced cell proliferation in an epithelial cell model of the crypt-villus axis. However, effects on differentiation, digestive function, and epithelial barrier function differed between the HMOs tested. These results suggest differential roles for specific HMOs in maturation of the gastrointestinal tract. PMID:24572036

Holscher, Hannah D; Davis, Steven R; Tappenden, Kelly A

2014-05-01

268

Radioimmunoassay of human intestinal goblet cell mucin. Investigation of mucus from different organs and species.  

PubMed Central

We have developed a double-antibody radioimmunoassay for the quantitative measurement of human goblet cell mucin (GCM) in order to study intestinal mucus in human and other species. The assay used 3H-labeled mucin as the antigen, rabbit antisera, and sheep anti-rabbit IgG antisera as the second antibody. A number of applications of the assay were investigated. A survey of human tissues revealed that mucins of the rectum, colon, and small intestine had identical affinity for the rabbit antibody, whereas lung eyelid conjunctiva, esophagus, and stomach reacted less strongly. GCM concentration ranged from 1.9 to 14 microgram mucin protein/mg tissue protein in the small and large intestine, respectively. The radioimmunoassay was also found to be useful as a marker during the isolation of GCM from human ileal extracts, where it indicated that a 10,000-fold purification had been achieved. Antigenic determinants of the mucin did not rely upon ABH blood group-specific terminal sugars in oligosaccharide chains. A comparison of mucins among various species revealed a partial species specificity of the GCM antibody. Human GCM cross-reacted with dog, monkey, and rabbit mucins, but not with mucins of rat, pig, toad, and oyster. Organ distributions of cross-reactive mucins in rabbit tissues indicated a pattern that was qualitatively similar to that seen in human tissues. Possible implications of these findings for autoimmune diseases are briefly discussed.

Qureshi, R; Forstner, G G; Forstner, J F

1979-01-01

269

A third P-domain peptide gene (TFF3), human intestinal trefoil factor, maps to 21q22.3.  

PubMed

Small peptides displaying a cysteine-rich module (termed P-domain or trefoil motif) form a recently increasing group of peptides abundantly expressed at mucosal surfaces of specific tissues and are associated with the maintenance of surface integrity. The estrogen-inducible pS2 gene (BCEI) and the human homolog to the porcine spasmolytic peptide (hsP) gene (SML1) appear synchronously expressed in healthy stomach mucosa and several carcinomas of the gastrointestinal tract. Both genes were shown to be located at 21q22.3. A new trefoil peptide from human intestinal mucosa (hITF/hP1.B) and its gene (TFF3) were described recently. By PCR analysis of a somatic cell hybrid panel and FISH using two large genomic recombinants (110 kb, 210 kb) cloned in the Bacterial Artificial Chromosome (BAC) system, we show that this gene coding for the new member of human P-domain/trefoil peptides also maps to chromosome region 21q22.3 suggesting a physical linkage of all three trefoil peptide genes. PMID:8641134

Schmitt, H; Wundrack, I; Beck, S; Gött, P; Welter, C; Shizuya, H; Simon, M I; Blin, N

1996-01-01

270

Characterization of bacterial community shift in human Ulcerative Colitis patients revealed by Illumina based 16S rRNA gene amplicon sequencing  

PubMed Central

Background The healthy human intestine is represented by the presence of bacterial communities predominantly belonging to obligate anaerobes; however disparity and dysanaerobiosis in intestinal microflora may lead to the progression of ulcerative colitis (UC). The foremost aim of this study is to consider and compare the gut microbiota composition in patients suffering from different stages of UC. Methods This study represents data from the biopsy samples of six individuals suffering from UC. The samples were collected by colonoscopy and were processed immediately for isolation of DNA. Mucosal microbiota was analyzed by means of 16S rRNA gene-based Illumina high throughput sequencing. Quantitative real-time PCR (qPCR) was performed to determine total bacterial abundances. Results Analysis of 23,927 OTUs demonstrated a significant reduction of bacterial diversity consistently from phylum to species level (p?bacterial count was detected in patients suffering from severe inflammatory stage (2.98 +/-0.49 E?+?09/ml) when compared with patients with moderate (1.03+/-0.29 E?+?08/ml) and mild (1.76 +/-0.34 E?+?08/ml) stages of inflammation. Conclusion The reduction of bacterial diversity with an increase in the total bacterial count indicates a shift of bacterial communities which signifies dysbiosis and dysanaerobiosis at the mucosal level for patients suffering from UC.

2014-01-01

271

Orchestration of Neutrophil Movement by Intestinal Epithelial Cells in Response to Salmonella typhimurium Can Be Uncoupled from Bacterial Internalization  

Microsoft Academic Search

Intestinal epithelial cells respond to Salmonella typhimurium by internalizing this pathogen and secreting, in a polarized manner, an array of chemokines which direct polymorphonuclear leukocyte (PMN) movement. Notably, interleukin-8 (IL-8) is secreted basolaterally and directs PMN through the lamina propria, whereas pathogen-elicited epithelial chemoattractant (PEEC) is secreted apically and directs PMN migration across the epithelial monolayer to the intestinal lumen.

ANDREW T. GEWIRTZ; ANDREW M. SIBER; JAMES L. MADARA; BETH A. MCCORMICK

272

Characterization of carnosine uptake and its physiological function in human intestinal epithelial Caco-2 cells.  

PubMed

Carnosine (beta-Ala-L-His) is known to have the physiological functions of an antioxidant. Although dietary carnosine is thought to be absorbed across intestinal epithelial cells, the mechanism for this absorption is not yet well understood and its function in the intestinal tract is also obscure. The intestinal transport of carnosine was characterized in the present study by using human intestinal Caco-2 cells, and its physiological function in these cells was further examined. The carnosine uptake was proton-dependent, being activated by lowering the apical pH value. Its uptake was significantly inhibited by other dipeptides, whereas it was not inhibited by other amino acids. These characteristics of the carnosine uptake strongly suggest its transport into the cells via peptide transporter 1 (PepT1). Since carnosine has antioxidative activity, we studied its effect on the H2O2-induced secretion of inflammatory cytokines in Caco-2 cells. The H2O2 induced increase in IL-8 secretion was inhibited by a pretreatment with carnosine for 3 h, this inhibition being presented in a dose-dependent manner. These results suggest that carnosine had a protective effect against oxidative stress in intestinal epithelial cells. PMID:15630234

Son, Dong Ok; Satsu, Hideo; Kiso, Yoshinobu; Shimizu, Makoto

2004-01-01

273

Recombinant Human Epidermal Growth Factor Accelerates Recovery of Mouse Small Intestinal Mucosa After Radiation Damage  

SciTech Connect

Purpose: To determine whether systemically administered recombinant human epidermal growth factor (rhEGF) accelerates the recovery of mouse small intestinal mucosa after irradiation. Methods and Materials: A mouse mucosal damage model was established by administering radiation to male BALB/c mice with a single dose of 15 Gy applied to the abdomen. After irradiation, rhEGF was administered subcutaneously at various doses (0.04, 0.2, 1.0, and 5.0 mg/kg/day) eight times at 2- to 3-day intervals. The evaluation methods included histologic changes of small intestinal mucosa, change in body weight, frequency of diarrhea, and survival rate. Results: The recovery of small intestinal mucosa after irradiation was significantly improved in the mice treated with a high dose of rhEGF. In the mice that underwent irradiation without rhEGF treatment, intestinal mucosal ulceration, mucosal layer damage, and severe inflammation occurred. The regeneration of villi was noticeable in mice treated with more than 0.2 mg/kg rhEGF, and the villi recovered fully in mice given more than 1 mg/kg rhEGF. The frequency of diarrhea persisting for more than 3 days was significantly greater in the radiation control group than in the rhEGF-treated groups. Conclusions: Systemic administration of rhEGF accelerates recovery from mucosal damage induced by irradiation. We suggest that rhEGF treatment shows promise for the reduction of small intestinal damage after irradiation.

Lee, Kang Kyoo [Department of Radiation Oncology, University of Wonkwang School of Medicine, Iksan (Korea, Republic of); Jo, Hyang Jeong [Department of Pathology, University of Wonkwang School of Medicine, Iksan (Korea, Republic of); Hong, Joon Pio [Department of Plastic and Reconstructive Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Lee, Sang-wook [Department of Radiation Oncology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)], E-mail: lsw@amc.seoul.kr; Sohn, Jung Sook [Vestibulocochlear Research Center, University of Wonkwang School of Medicine, Iksan (Korea, Republic of); Moon, Soo Young [Department of Radiation Oncology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Yang, Sei Hoon; Shim, Hyeok [Department of Internal Medicine, University of Wonkwang School of Medicine, Iksan (Korea, Republic of); Lee, Sang Ho [Department of Radiology, Iksan General Hospital, Iksan (Korea, Republic of); Ryu, Seung-Hee [Department of Radiation Oncology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Moon, Sun Rock [Department of Radiation Oncology, University of Wonkwang School of Medicine, Iksan (Korea, Republic of)

2008-07-15

274

Characterization of UDP-glucuronosyltransferases involved in glucuronidation of diethylstilbestrol in human liver and intestine.  

PubMed

Diethylstilbestrol (DES), a synthetic estrogen, is famous for its carcinogenic effects. Human exposure to this compound can occur frequently through dietary ingestion and medical treatment. Glucuronidation has been demonstrated to be a predominant metabolic pathway for DES in human. Therefore, glucuronidation metabolism may have a significant impact on its toxicities, and it is essential to clarify this metabolic pathway. Accordingly, this in vitro study is designed to characterize the UGTs involved in DES glucuronidation and, furthermore, to identify the roles of individual isoforms in the reaction in liver and intestine. Human liver microsomes (HLM) displayed much higher potential for DES glucuronidation than human intestinal microsomes (HIM). The intrinsic clearances in HLM and HIM were demonstrated to be 459 and 14 ?L/min/mg protein, respectively. Assays with recombinant UGTs demonstrated that UGT1A1, -1A3, -1A8, and -2B7 could catalyze DES glucuronidation, among which UGT2B7 showed the highest affinity. Chemical inhibitors of UGT2B7 and UGT1A1/1A3 both displayed similar inhibition against the reaction in UGT2B7 and HLM. In addition, DES glucuronidation in individual HLM exhibited a large individual variability and strongly correlated to UGT2B7 activity. All evidence indicates that UGT2B7 may act as a major enzyme responsible for DES glucuronidation in human liver. For HIM, both UGT2B7 inhibitor and UGT1A1/1A3/1A8 inhibitor exerted moderate inhibition. It is suggested that although UGT2B7 contributes to DES glucuronidation in intestine, other UGTs may contribute equally. In summary, this study characterizes human UGTs involved in DES glucuronidation in human liver and intestine, which may be helpful for further study about DES-related toxicities. PMID:23126256

Zhu, Liangliang; Ge, Guangbo; Liu, Yong; Guo, Zhimou; Peng, Chengcheng; Zhang, Feng; Cao, Yunfeng; Wu, Jingjing; Fang, Zhongze; Liang, Xinmiao; Yang, Ling

2012-12-17

275

The bioavailability of apigenin-7-glucoside is influenced by human intestinal microbiota in rats.  

PubMed

We investigated the impact of human intestinal microbiota on bioavailability of the flavone apigenin-7-glucoside (A7G) by comparing germ-free and human microbiota-associated (HMA) rats. First, the ability of the human intestinal microbiota to convert A7G was proven in vitro by incubating A7G with fecal suspensions. Apigenin, naringenin, and 3-(4-hydroxyphenyl)propionic acid were formed as main metabolites. After application of A7G to germ-free rats, apigenin, luteolin, and their conjugates were detected in urine and feces. In HMA rats, naringenin, eriodictyol, phloretin, 3-(3,4-dihydroxyphenyl)propionic acid, 3-(4-hydroxyphenyl)propionic acid, 3-(3-hydroxyphenyl)propionic acid, and 4-hydroxycinnamic acid in their free and conjugated forms were additionally formed. In whole-blood samples from germ-free and HMA rats, only apigenin conjugates and phloretin, respectively, were detected. The total excretion of A7G and its metabolites within 48 h was similarly low in both germ-free and HMA rats, with 11 and 13% of the A7G dose, respectively. In germ-free rats, A7G metabolites dominated by apigenin and its conjugates were mainly excreted with feces. In contrast, the compounds in HMA rats were predominantly recovered from urine, 3-(4-hydroxyphenyl)propionic acid being the main metabolite. The ability of selected gut bacteria and the host intestinal mucosa to deglycosylate A7G was tested using cell extracts. Apigenin was formed by cytosolic extracts of Eubacterium ramulus and Bacteroides distasonis and by the microsomal fraction of the small intestinal mucosa of rats. Overall, human intestinal microbiota largely contributed to A7G metabolism, indicating its influence on the bioactivity of flavones. PMID:19403720

Hanske, Laura; Loh, Gunnar; Sczesny, Silke; Blaut, Michael; Braune, Annett

2009-06-01

276

Molecular analysis of human forearm superficial skin bacterial biota  

PubMed Central

The microbial ecology of human skin is complex, but little is known about its species composition. We examined the diversity of the skin biota from the superficial volar left and right forearms in six healthy subjects using broad-range small subunit rRNA genes (16S rDNA) PCR-based sequencing of randomly selected clones. For the initial 1,221 clones analyzed, 182 species-level operational taxonomic units (SLOTUs) belonging to eight phyla were identified, estimated as 74.0% [95% confidence interval (C.I.), ?64.8–77.9%] of the SLOTUs in this ecosystem; 48.0 ± 12.2 SLOTUs were found in each subject. Three phyla (Actinobacteria, Firmicutes, and Proteobacteria) accounted for 94.6% of the clones. Most (85.3%) of the bacterial sequences corresponded to known and cultivated species, but 98 (8.0%) clones, comprising 30 phylotypes, had <97% similarity to prior database sequences. Only 6 (6.6%) of the 91 genera and 4 (2.2%) of the 182 SLOTUs, respectively, were found in all six subjects. Analysis of 817 clones obtained 8–10 months later from four subjects showed additional phyla (numbering 2), genera (numbering 28), and SLOTUs (numbering 65). Only four (3.4%) of the 119 genera (Propionibacteria, Corynebacteria, Staphylococcus, and Streptococcus) were observed in each subject tested twice, but these genera represented 54.4% of all clones. These results show that the bacterial biota in normal superficial skin is highly diverse, with few well conserved and well represented genera, but otherwise low-level interpersonal consensus.

Gao, Zhan; Tseng, Chi-hong; Pei, Zhiheng; Blaser, Martin J.

2007-01-01

277

Monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract.  

PubMed

The monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract was investigated with seven healthy subjects having a low number of fecal lactobacilli. An increase of fecal lactobacilli (10(3.2-5.2) CFU/g feces) was recognized after ingestion of yogurt with SBT2055 by the subjects. A high positive rate of L. gasseri in fecal lactobacilli detected from the subjects (over 70% at 2nd weeks of feeding) was also observed during the ingestion period using the species-specific PCR system. These findings indicate that the SBT2055 strain in yogurt survived in the human intestinal tract and was recovered from human feces. PMID:17116981

Takahashi, Hidetoshi; Fujita, Takashi; Suzuki, Yutaka; Benno, Yoshimi

2006-01-01

278

Adherence of Lactobacillus Species to Human Fetal Intestinal Cells1  

Microsoft Academic Search

Thirty-two lactobacilli were tested for ability to adhere to a human fetal in- testinal epithelial cell line. By an in vitro system, two adherence mechanisms were found. One mechanism, requiring calcium in the adherence reaction, was nonspecific and allowed all lactobacilli tested to adhere. The other system, not requiring calcium, was found in four strains, all human Lactobacillus acidopbilus isolates.

E. G. Kleeman; T. R. Klaenhammer

1982-01-01

279

Detection of Microsporidia (Enterocytozoon bieneusi)in Intestinal Biopsy Specimens from Human Immunodeficiency Virus-Infected Patients by PCR  

Microsoft Academic Search

Intestinal microsporidiosis has been implicated as a major cause of chronic diarrhea in human immuno- deficiency virus (HIV)-infected patients. So far diagnosis depends on direct visualization of the parasites by light and transmission electron microscopy. We evaluated the diagnostic value of microsporidian DNA am- plification by PCR on duodenal biopsy specimens obtained from patients with and without intestinal micro- sporidiosis

CASPAR FRANZEN; ANDREAS MULLER; PETRA HEGENER; BERND SALZBERGER; PIA HARTMANN; GERD FATKENHEUER; VOLKER DIEHL

280

Characterization of Butyrate Uptake by Nontransformed Intestinal Epithelial Cell Lines  

Microsoft Academic Search

Butyrate (BT) is one of the main end products of anaerobic bacterial fermentation of dietary fiber within the human colon.\\u000a Among its recognized effects, BT inhibits colon carcinogenesis. Our aim was to characterize uptake of BT by two nontransformed\\u000a intestinal epithelial cell lines: rat small intestinal epithelial (IEC-6) and fetal human colonic epithelial (FHC) cells.\\u000a Uptake of 14C-BT by IEC-6

Pedro GoncalvesJoao; João R. Araújo; Fátima Martel

2011-01-01

281

Activation of RegIII?/? and interferon ? expression in the intestinal tract of SCID mice: an innate response to bacterial colonisation of the gut  

PubMed Central

Background and aims: The mechanisms by which commensal bacteria provoke intestinal inflammation in animal models of inflammatory bowel disease (IBD) remain incompletely defined, leading to increasing interest in the innate immune response of the colonic mucosa to bacterial colonisation. Methods: Using gene expression profiling of colonic RNA from C.B17.SCID germ free mice and those colonised with altered Schaedler’s flora, we investigated the innate immune response to bacterial colonisation in vivo. The two most consistently induced gene groups were RegIII? and ? as well as interferon ? (IFN-?) response genes. Results: Using quantitative reverse transcription-polymerase chain reaction, we showed that RegIII?, RegIII?, and IFN-? were constitutively expressed in the colon of conventionally housed SCID mice compared with either germ free SCID or conventionally housed BALB/c mice. Induction of these genes was reproduced by chronic monoassociation of germ free SCID mice with either of two separate gut commensal bacterial species—segmented filamentous bacteria and Schaedler’s Escherichia coli. The cellular source for IFN-? on monoassociation of SCID mice with Schaedler’s E coli was localised to a subset of intraepithelial natural killer (IENK) cells that express asialo-GM1. In vivo IFN-? immunoneutralisation studies failed to demonstrate any alteration in RegIII? or ? expression. Conclusions: Thus bacterial colonisation of the colon independently activates two distinct innate immune cell types at the mucosal interface with the colonic lumen, intestinal epithelial cells, and IENK cells, a response that may be regulated by the adaptive immune system. These innate immune responses may play a role in the pathogenesis of colitis in SCID adoptive transfer models in mice and possibly in patients with IBD.

Keilbaugh, S A; Shin, M E; Banchereau, R F; McVay, L D; Boyko, N; Artis, D; Cebra, J J; Wu, G D

2005-01-01

282

Diversity of Human Vaginal Bacterial Communities and Associations with Clinically Defined Bacterial Vaginosis  

Microsoft Academic Search

Bacterial vaginosis (BV) is a common syndrome associated with numerous adverse health outcomes in women. Despite its medical importance, the etiology and microbial ecology of BV remain poorly understood. We used broad-range PCR to census the community structure of the healthy and BV-affected vaginal microbial ecosystems and synthesized current publicly available bacterial 16S rRNA gene sequence data from this environment.

Brian B. Oakley; Tina L. Fiedler; Jeanne M. Marrazzo; David N. Fredricks

2008-01-01

283

Effects of cycle exercise on intestinal absorption in humans.  

PubMed

Intestinal absorption was measured in six trained male cyclists during rest, exercise, and recovery periods with the segmental perfusion technique. Each subject passed a multilumen tube into the duodenojejunum. The experiments consisted of 1) a sequence of 1-h bouts of cycling exercise at 30, 50, and 70% maximal O2 uptake (Vo2max) separated by 1-h rest periods or 2) a 90-min bout at 70% VO2max. The cycling was performed on a constant-load Velodyne trainer. Absorption of water and a 6% carbohydrate-electrolyte (2% glucose, 6% sucrose, 20 meq Na+, 2.6 meq K+) solution (both perfused at 15 ml/min) were compared. The effects of perfusing an isotonic electrolyte solution during mild (30% VO2max) exercise were also studied. Fluid was sampled every 10 min from ports 10 and 50 cm distal to the infusion site. Water flux was determined by differences in polyethylene glycol concentration across the 40-cm test segment. Results showed 1) no difference in water or electrolyte absorption rates among rest, exercise, and recovery periods; 2) no difference in absorption rates among the three exercise intensities or different exercise durations; and 3) significantly greater fluid absorption rates from the carbohydrate-electrolyte (CE) solution than from water. Water flux during rest, exercise, and recovery was about sixfold greater from the CE solution than from the isotonic solution without carbohydrate. We conclude that 1) exercise has no effect on water or solute absorption in the duodenojejunum, 2) fluid absorption occurs significantly faster from a CE solution than from water, and 3) fluid absorption is increased sixfold by addition of carbohydrate to an electrolyte solution. PMID:1778952

Gisolfi, C V; Spranger, K J; Summers, R W; Schedl, H P; Bleiler, T L

1991-12-01

284

Interferon Regulatory Factor 1 (IRF-1) and IRF-2 Distinctively Up-Regulate Gene Expression and Production of Interleukin7 in Human Intestinal Epithelial Cells  

Microsoft Academic Search

Intestinal epithelial cell-derived interleukin (IL)-7 functions as a pleiotropic and nonredundant cytokine in the human intestinal mucosa; however, the molecular basis of its production has remained totally unknown. We here showed that human intestinal epithelial cells both constitutively and when induced by gamma interferon (IFN-) produced IL-7, while several other factors we tested had no effect. Transcriptional regula- tion via

Shigeru Oshima; Tetsuya Nakamura; Shin Namiki; Eriko Okada; Kiichiro Tsuchiya; Ryuichi Okamoto; Motomi Yamazaki; Takanori Yokota; Masatoshi Aida; Yuki Yamaguchi; Takanori Kanai; Hiroshi Handa; Mamoru Watanabe

2004-01-01

285

Hydrolysis of Pyrethroids by Human and Rat Tissues: Examination of Intestinal, Liver and Serum Carboxylesterases  

PubMed Central

Hydrolytic metabolism of pyrethroid insecticides in humans is one of the major catabolic pathways that clear these compounds from the body. Rodent models are often used to determine the disposition and clearance rates of these esterified compounds. In this study the distribution and activities of esterases that catalyze pyrethroid metabolism have been investigated in vitro using several human and rat tissues, including small intestine, liver, and serum. The major esterase in human intestine is carboxylesterase 2 (hCE2). We found that the pyrethroid trans-permethrin is effectively hydrolyzed by a sample of pooled human intestinal microsomes (5 individuals), while deltamethrin and bioresmethrin are not. This result correlates well with the substrate specificity of recombinant hCE2 enzyme. In contrast, a sample of pooled rat intestinal microsomes (5 animals) hydrolyze trans-permethrin 4.5-fold slower than the sample of human intestinal microsomes. Furthermore, it is demonstrated that pooled samples of cytosol from human or rat liver are ~2-fold less hydrolytically active (normalized per mg protein) than the corresponding microsomal fraction toward pyrethroid substrates; however, the cytosolic fractions do have significant amounts (~40%) of the total esteratic activity. Moreover, a 6-fold interindividual variation in carboxylesterase 1 protein expression in human hepatic cytosols was observed. Human serum was shown to lack pyrethroid hydrolytic activity, but rat serum has hydrolytic activity that is attributed to a single CE isozyme. We purified the serum CE enzyme to homogeneity to determine its contribution to pyrethroid metabolism in the rat. Both trans-permethrin and bioresmethrin were effectively cleaved by this serum CE, but deltamethrin, esfenvalerate, alpha-cypermethrin, and cis-permethrin were slowly hydrolyzed. Lastly, two model lipase enzymes were examined for their ability to hydrolyze pyrethroids. However, no hydrolysis products could be detected. Together, these results demonstrate that extrahepatic esterolytic metabolism of specific pyrethroids may be significant. Moreover, hepatic cytosolic and microsomal hydrolytic metabolism should each be considered during the development of pharmacokinetic models that predict the disposition of pyrethroids and other esterified compounds.

Crow, J. Allen; Borazjani, Abdolsamad; Potter, Philip M.; Ross, Matthew K.

2009-01-01

286

Hydrolysis of pyrethroids by human and rat tissues: Examination of intestinal, liver and serum carboxylesterases  

SciTech Connect

Hydrolytic metabolism of pyrethroid insecticides in humans is one of the major catabolic pathways that clear these compounds from the body. Rodent models are often used to determine the disposition and clearance rates of these esterified compounds. In this study the distribution and activities of esterases that catalyze pyrethroid metabolism have been investigated in vitro using several human and rat tissues, including small intestine, liver and serum. The major esterase in human intestine is carboxylesterase 2 (hCE2). We found that the pyrethroid trans-permethrin is effectively hydrolyzed by a sample of pooled human intestinal microsomes (5 individuals), while deltamethrin and bioresmethrin are not. This result correlates well with the substrate specificity of recombinant hCE2 enzyme. In contrast, a sample of pooled rat intestinal microsomes (5 animals) hydrolyze trans-permethrin 4.5-fold slower than the sample of human intestinal microsomes. Furthermore, it is demonstrated that pooled samples of cytosol from human or rat liver are {approx} 2-fold less hydrolytically active (normalized per mg protein) than the corresponding microsomal fraction toward pyrethroid substrates; however, the cytosolic fractions do have significant amounts ({approx} 40%) of the total esteratic activity. Moreover, a 6-fold interindividual variation in carboxylesterase 1 protein expression in human hepatic cytosols was observed. Human serum was shown to lack pyrethroid hydrolytic activity, but rat serum has hydrolytic activity that is attributed to a single CE isozyme. We purified the serum CE enzyme to homogeneity to determine its contribution to pyrethroid metabolism in the rat. Both trans-permethrin and bioresmethrin were effectively cleaved by this serum CE, but deltamethrin, esfenvalerate, alpha-cypermethrin and cis-permethrin were slowly hydrolyzed. Lastly, two model lipase enzymes were examined for their ability to hydrolyze pyrethroids. However, no hydrolysis products could be detected. Together, these results demonstrate that extrahepatic esterolytic metabolism of specific pyrethroids may be significant. Moreover, hepatic cytosolic and microsomal hydrolytic metabolism should each be considered during the development of pharmacokinetic models that predict the disposition of pyrethroids and other esterified compounds.

Crow, J. Allen [Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100 Mississippi State, MS 39762-6100 (United States); Borazjani, Abdolsamad [Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100 Mississippi State, MS 39762-6100 (United States); Potter, Philip M. [Department of Molecular Pharmacology, St. Jude Children's Research Hospital, 332 North Lauderdale Memphis, TN 38105 (United States); Ross, Matthew K. [Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100 Mississippi State, MS 39762-6100 (United States)]. E-mail: mross@cvm.msstate.edu

2007-05-15

287

Bacterial lipopolysaccharide directly stimulates cortisol secretion in human adrenal cells.  

PubMed

Adrenomedullin and pro-adrenomedullin N-terminal 20 peptide (PAMP) are expressed in vascular cells and in the adrenal cortex and medulla. Lipopolysaccharide (LPS), a bacterial product that induces septic shock, is a potent stimulant of adrenomedullin secretion in vascular cell types and is also known to stimulate the hypothalamo-pituitary-adrenal axis (HPA). The present study was designed to investigate the actions of LPS on the human adrenocortical cell line, H295R. Exposure of cells to LPS for 24 hours had no effect on adrenomedullin or PAMP secretion, but was found to significantly and selectively increase cortisol secretion with no effect on aldosterone. Dibutyryl cAMP, however, caused a significant increase in both adrenomedullin and PAMP release over this time period. There are two conclusions which can be drawn from these observations. First that adrenomedullin and PAMP are regulated by different mechanisms in vascular and adrenal cells and second, that LPS is able to directly stimulate cortisol secretion, with implications for the physiological response to septic shock. PMID:12530637

Vakharia, K; Renshaw, D; Hinson, J P

2002-11-01

288

Intestinal absorption of epoxy-beta-carotenes by humans.  

PubMed Central

An increased intake of fruits and vegetables has been shown to be associated with reduced risk of cancer. In epidemiological studies, supplements of beta-carotene, which is abundant in fruits and vegetables, were not found to be beneficial in reducing the incidence of lung cancer in high-risk groups. Epoxycarotenoids are abundant in nature. 5,6-Epoxy-beta-carotene was much more active than beta-carotene in the induction of differentiation of NB4 cells [Duitsman, Becker, Barua and Olson (1996) FASEB J. 10, A732]. Epoxycarotenes may, therefore, have protective effects against cancer. In order to do this, however, epoxycarotenoids must be absorbed by the human body. There is no evidence that epoxycarotenoids, despite their abundance in dietary fruits and vegetables, are absorbed by humans. In this paper, it is demonstrated that orally administered dietary or synthetic epoxy-beta-carotenes are absorbed by humans, as indicated by their appearance in the circulating blood.

Barua, A B

1999-01-01

289

Metabolomics Analysis of Cistus monspeliensis Leaf Extract on Energy Metabolism Activation in Human Intestinal Cells  

PubMed Central

Energy metabolism is a very important process to improve and maintain health from the point of view of physiology. It is well known that the intracellular ATP production is contributed to energy metabolism in cells. Cistus monspeliensis is widely used as tea, spices, and medical herb; however, it has not been focusing on the activation of energy metabolism. In this study, C. monspeliensis was investigated as the food resources by activation of energy metabolism in human intestinal epithelial cells. C. monspeliensis extract showed high antioxidant ability. In addition, the promotion of metabolites of glycolysis and TCA cycle was induced by C. monspeliensis treatment. These results suggest that C. monspeliensis extract has an ability to enhance the energy metabolism in human intestinal cells.

Shimoda, Yoichi; Han, Junkyu; Kawada, Kiyokazu; Smaoui, Abderrazak; Isoda, Hiroko

2012-01-01

290

Hydrolysis of ester-type drugs by the purified esterase from human intestinal mucosa.  

PubMed

Esterase from human intestinal mucosa was purified 210 fold by solubilization with Triton X-100, chromatography on DEAE-cellulose, Sephadex G-100 and hydroxylapatite, and isoelectric focusing. The purified esterase showed a single band by polyacrylamide gel electrophoresis. The molecular weight of the purified esterase was estimated to be about 55,000 by gel filtration on Sephadex G-150, and the isoelectric point was 5.02. The purified esterase was strongly inhibited by diethyl p-nitrophenyl phosphate (E-600) and diisopropyl fluorophosphate (DFP), and was not inhibited by eserine sulfate and p-chloromercuribenzoate. The purified esterase from human intestinal mucosa was found to be one of the carboxylesterases. The purified esterase hydrolyzed ester-type drugs, i.e., aspirin, clofibrate, indanyl carbenicillin and procaine, but did not hydrolyze amide-type drugs and choline-type drugs. PMID:459153

Inoue, M; Morikawa, M; Tsuboi, M; Yamada, T; Sugiura, M

1979-02-01

291

Homology of the human intestinal Na+/glucose and Escherichia coli Na+/proline cotransporters.  

PubMed Central

Cotransport proteins are responsible for the active accumulation of organic substrates in cells. Na+ gradients provide the driving force for uptake of most substrates into eukaryotes and for a few substrates in some prokaryotes. We report here the cloning and sequencing of the human intestinal Na+/glucose cotransporter (SGLT1) and compare its structure with other cloned transporters. At the DNA level and the predicted amino acid and secondary structure levels, close homology is evident between the human and rabbit intestinal Na+/glucose cotransporters, and a significant homology is found between these and the Escherichia coli Na+/proline cotransporter (putP). No homology is detectible with other known proteins. We infer from these results that the mammalian Na+/glucose and prokaryote Na+/proline cotransporters share a common ancestral gene. Images

Hediger, M A; Turk, E; Wright, E M

1989-01-01

292

Transglutaminase 2 expression is enhanced synergistically by interferon-? and tumour necrosis factor-? in human small intestine  

PubMed Central

Transglutaminase 2 (TG2) is expressed ubiquitously, has multiple physiological functions and has also been associated with inflammatory diseases, neurodegenerative disorders, autoimmunity and cancer. In particular, TG2 is expressed in small intestine mucosa where it is up-regulated in active coeliac disease (CD). The aim of this work was to investigate the induction of TG2 expression by proinflammatory cytokines [interleukin (IL)-1, IL-6, tumour necrosis factor (TNF)-?, interferon (IFN)-? and IL-15] and the signalling pathways involved, in human epithelial and monocytic cells and in intestinal tissue from controls and untreated CD patients. Here we report that IFN-? was the most potent inducer of TG2 expression in the small intestinal mucosa and in four [Caco-2, HT-29, Calu-6 and human acute monocytic leukaemia cell line (THP-1)] of five cell lines tested. The combination of TNF-? and IFN-? produced a strong synergistic effect. The use of selective inhibitors of signalling pathways revealed that induction of TG2 by IFN-? was mediated by phosphoinositide 3-kinase (PI3K), while c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) were required for TNF-? activation. Quantitative polymerase chain reaction (PCR), flow cytometry and Western blot analysis showed that TG2 expression was blocked completely when stimulation by either TNF-? or IFN-? was performed in the presence of nuclear factor (NF)-?B inhibitors (sulphasalazine and BAY-117082). TG2 was up-regulated substantially by TNF-? and IFN-? in intestinal mucosa in untreated CD compared with controls. This study shows that IFN-?, a dominant cytokine in intestinal mucosa in active CD, is the most potent inducer of TG2, and synergism with TNF-? may contribute to exacerbate the pathogenic mechanism of CD. Selective inhibition of signalling pathways may be of therapeutic benefit.

Bayardo, M; Punzi, F; Bondar, C; Chopita, N; Chirdo, F

2012-01-01

293

Characterization of the bactericidal effect of dietary sphingosine and its activity under intestinal conditions  

Microsoft Academic Search

Sphingosine is known as a natural antimicrobial agent, protecting the human skin from bacterial colonization and possibly affecting the intestinal microbial community after ingestion. In this study we further investigated the antibacterial spectrum of dietary d-eythro-sphingosine in saline towards three intestinal pathogens and to the health promoting lactobacilli and bifidobacteria. The degree of bactericidal effect was studied using plate counts

Sam Possemiers; John Van Camp; Selin Bolca; Willy Verstraete

2005-01-01

294

Interleukin 23 production by intestinal CD103(+)CD11b(+) dendritic cells in response to bacterial flagellin enhances mucosal innate immune defense.  

PubMed

Microbial penetration of the intestinal epithelial barrier triggers inflammatory responses that include induction of the bactericidal C-type lectin RegIII?. Systemic administration of flagellin, a bacterial protein that stimulates Toll-like receptor 5 (TLR5), induces epithelial expression of RegIII? and protects mice from intestinal colonization with antibiotic-resistant bacteria. Flagellin-induced RegIII? expression is IL-22 dependent, but how TLR signaling leads to IL-22 expression is incompletely defined. By using conditional depletion of lamina propria dendritic cell (LPDC) subsets, we demonstrated that CD103(+)CD11b(+) LPDCs, but not monocyte-derived CD103(-)CD11b(+) LPDCs, expressed high amounts of IL-23 after bacterial flagellin administration and drove IL-22-dependent RegIII? production. Maximal expression of IL-23 subunits IL-23p19 and IL-12p40 occurred within 60 min of exposure to flagellin. IL-23 subsequently induced a burst of IL-22 followed by sustained RegIII? expression. Thus, CD103(+)CD11b(+) LPDCs, in addition to promoting long-term tolerance to ingested antigens, also rapidly produce IL-23 in response to detection of flagellin in the lamina propria. PMID:22306017

Kinnebrew, Melissa A; Buffie, Charlie G; Diehl, Gretchen E; Zenewicz, Lauren A; Leiner, Ingrid; Hohl, Tobias M; Flavell, Richard A; Littman, Dan R; Pamer, Eric G

2012-02-24

295

Autochthonous Intestinal Bacterial Flora and Cholesterol Levels in Specific Pathogen-free Swine Fed High-Lipid and High-Sucrose Diets  

PubMed Central

Graber, C. D. (Baylor University College of Medicine, Houston, Tex.). R. W. Moore, M. Suzuki, W. E. Redmond, R. M. O'Neal, and B. M. Lockhart. Autochthonous intestinal bacterial flora and cholesterol levels in specific pathogen-free swine fed high-lipid and high-sucrose diets. J. Bacteriol. 92:1290–1297. 1966.—Thirty-two specific pathogen-free (SPF) and conventional swine fed high fat, high sugar, and a standard ration were cultured for intestinal flora, and their blood cholesterol levels were measured. The diets, whether sterilized or not sterilized, fed ad libitum or restricted, did not alter bacterial flora greatly or influence blood cholesterol levels. Anaerobes outnumbered aerobes by several logs. Four autochthonous bacteria, lactobacilli, Escherichia coli, enterococci, and gram-variable, nonspore-forming anaerobes (GVNSA; a type of bacteroides), were shown to be constantly present in all animals regardless of dietary conditions. From the duodenum and jejunum of 14 pigs, GVNSA and Bacteroides nigrescens were cultured in rather large numbers, a finding not previously reported in swine or in most other mammals. This finding may have special significance in reference to bile acid and cholesterol metabolism.

Graber, C. D.; Moore, R. W.; Suzuki, M.; Redmond, W. E.; O'Neal, R. M.; Lockhart, B. M.

1966-01-01

296

Effects of recombinant human intestinal trefoil factor on trinitrobenzene sulphonic acid induced colitis in rats  

Microsoft Academic Search

Intestinal trefoil factor (ITF) has been proved to be effective in treatment of ulcerative colitis. However, the mechanisms\\u000a of it remain unclear. In this study, we observed the effects of combined treatment with 5-aminosalicylic acid (5-ASA) and\\u000a recombinant human ITF (rhITF) on the expression of Myeloperoxidase (MPO), nuclear factor-?B (NF-?B) and epidermal growth factor\\u000a (EGF) in trinitrobenzene sulphonic acid (TNBS)

Jin Li; Rui Zhou; Wen-cheng He; Bing Xia

297

Detection of attachment of enterotoxigenic Escherichia coli (ETEC) to human small intestinal cells by enzyme immunoassay  

Microsoft Academic Search

Simple immunoassays were developed to study the binding between enterocytes of the small intestine and other cell types, and enterotoxigenic Escherichia coli (ETEC). CFA\\/I or CFA\\/II pilus protein or CFA-positive E. coli bacteria were wells of microtitre plates and incubated with vesicles or crude mucus prepared from human brush border enterocytes. Binding of the cell preparations was detected by adding

Tracey L. Mynott; Richard K. J. Luke; David S. Chandler

1995-01-01

298

Autoradiographic quantification of vasoactive intestinal peptide binding sites in sections from human blood mononuclear cell pellets  

SciTech Connect

Quantitative autoradiographic methods were utilized to characterize specific, high-affinity vasoactive intestinal peptide binding sites (Kd = 310 +/- 60 pmol/L; Bmax = 93 +/- 11 fmol/mg protein) in frozen sections obtained from a mononuclear cell pellet derived from 20 ml of human blood. The method is at least one order of magnitude more sensitive than conventional membrane binding techniques, and it has the potential for wide applications in studies of neuropeptide, biogenic amine, and drug binding in clinical samples.

Gutkind, J.S.; Kurihara, M.; Castren, E.; Saavedra, J.M.

1988-09-01

299

Canine Intestinal Contents vs . Simulated Media for the Assessment of Solubility of Two Weak Bases in the Human Small Intestinal Contents  

Microsoft Academic Search

\\u000a Purpose  This study was conducted to assess the relative usefulness of canine intestinal contents and simulated media in the prediction\\u000a of solubility of two weak bases (dipyridamole and ketoconazole) in fasted and fed human intestinal aspirates that were collected\\u000a under conditions simulating those in bioavailability\\/bioequivalence studies.\\u000a \\u000a \\u000a \\u000a Methods  After administration of 250 mL of water or 500 mL of Ensure plus [both containing 10 mg\\/mL polyethylene

Lida Kalantzi; Eva Persson; Britta Polentarutti; Bertil Abrahamsson; Konstantinos Goumas; Jennifer B. Dressman; Christos Reppas

2006-01-01

300

Mutagenicity of arbutin in mammalian cells after activation by human intestinal bacteria.  

PubMed

Arbutin (hydroquinone-beta-D-glucopyranoside) is present in various food plants. Its aglycone, hydroquinone, is mutagenic and carcinogenic. We investigated whether hydroquinone may be released under conditions encountered in the human gastrointestinal tract. Arbutin was stable in artificial gastric juice. Fecal slurries from nine human subjects completely converted arbutin (2 mM) into hydroquinone. Four of nine representative human intestinal species investigated, namely Eubacterium ramulus, Enterococcus casseliflavus, Bacteroides distasonis, and Bifidobacterium adolescentis, deglycosylated arbutin at rates of 21.08, 16.62, 8.43 and 3.59 nmol x min(-1) x (mg protein)(-1), respectively. In contrast, homogenates from small intestinal mucosa and cytosolic fractions from colon mucosa deglycosylated arbutin at substantially lower rates: 0.50 and 0.09 nmol x min(-1) x (mg protein)(-1), respectively. Arbutin, unlike hydroquinone, did not induce gene mutations in Chinese hamster V79 cells in the absence of an activating system. However, in the presence of cytosolic fractions from E. ramulus or B. distasonis, arbutin was strongly mutagenic. Cytosolic fraction from Escherichia coli, showing no arbutin glycosidase activity, was not able to activate arbutin in this model system. The release of the proximate mutagen hydroquinone from arbutin by intestinal bacteria in the immediate vicinity of the colon mucosa may pose a potential risk. PMID:16904805

Blaut, Michael; Braune, Annett; Wunderlich, Sandra; Sauer, Patrick; Schneider, Heiko; Glatt, Hansruedi

2006-11-01

301

Paneth cell granule depletion in the human small intestine under infective and nutritional stress.  

PubMed

Paneth cells are important contributors to the intestinal antimicrobial barrier through synthesis and release of antimicrobial peptides and proteins. Animal studies indicate that Paneth cell numbers, location and granule morphology are altered by infection and zinc status. We examined human tissue to determine whether Paneth cell numbers, distribution or granule morphology are altered in infective, inflammatory and nutritional disorders. Archival sections from infective disorders (giardiasis, cryptosporidiosis, HIV, helminth infection) were compared with active inflammatory conditions (coeliac, Crohn's and graft-versus-host diseases) and histologically normal tissues. A subset of tissues was studied by electron microscopy and TUNEL staining for apoptosis. Human defensin-5 (HD5) peptide and mRNA was analysed by immunohistochemistry, in situ hybridization and quantitative reverse transcription polymerase chain reaction. Sections from a tropical population cohort study were then analysed to determine the relationship of granule depletion to infection, nutritional status and plasma zinc concentration. In HIV-related cryptosporidiosis, but not other disorders, Paneth cells were reduced in number and markedly depleted of granules. Paneth cell granule depletion was associated with reduced HD5 immunoreactivity, but this was not due to apoptosis and there was no reduction in mRNA transcripts. In the tropical population studied, depletion of granules was associated with reduced body mass index, reduced plasma zinc levels and HIV infection. Paneth cell granules in human small intestine may be depleted in response to infective and nutritional stress. We postulate that this is one mechanism through which zinc status influences host susceptibility to intestinal infection. PMID:14738460

Kelly, P; Feakins, R; Domizio, P; Murphy, J; Bevins, C; Wilson, J; McPhail, G; Poulsom, R; Dhaliwal, W

2004-02-01

302

Paneth cell granule depletion in the human small intestine under infective and nutritional stress  

PubMed Central

Paneth cells are important contributors to the intestinal antimicrobial barrier through synthesis and release of antimicrobial peptides and proteins. Animal studies indicate that Paneth cell numbers, location and granule morphology are altered by infection and zinc status. We examined human tissue to determine whether Paneth cell numbers, distribution or granule morphology are altered in infective, inflammatory and nutritional disorders. Archival sections from infective disorders (giardiasis, cryptosporidiosis, HIV, helminth infection) were compared with active inflammatory conditions (coeliac, Crohn's and graft-versus-host diseases) and histologically normal tissues. A subset of tissues was studied by electron microscopy and TUNEL staining for apoptosis. Human defensin-5 (HD5) peptide and mRNA was analysed by immunohistochemistry, in situ hybridization and quantitative reverse transcription polymerase chain reaction. Sections from a tropical population cohort study were then analysed to determine the relationship of granule depletion to infection, nutritional status and plasma zinc concentration. In HIV-related cryptosporidiosis, but not other disorders, Paneth cells were reduced in number and markedly depleted of granules. Paneth cell granule depletion was associated with reduced HD5 immunoreactivity, but this was not due to apoptosis and there was no reduction in mRNA transcripts. In the tropical population studied, depletion of granules was associated with reduced body mass index, reduced plasma zinc levels and HIV infection. Paneth cell granules in human small intestine may be depleted in response to infective and nutritional stress. We postulate that this is one mechanism through which zinc status influences host susceptibility to intestinal infection.

KELLY, P; FEAKINS, R; DOMIZIO, P; MURPHY, J; BEVINS, C; WILSON, J; MCPHAIL, G; POULSOM, R; DHALIWAL, W

2004-01-01

303

Rapid and Accurate Diagnosis of Human Intestinal Spirochetosis by Fluorescence In Situ Hybridization?  

PubMed Central

Human intestinal spirochetosis (HIS) is associated with overgrowth of the large intestine by spirochetes of the genus Brachyspira. The microbiological diagnosis of HIS is hampered by the fastidious nature and slow growth of Brachyspira spp. In clinical practice, HIS is diagnosed histopathologically, and a significant portion of cases may be missed. Fluorescence in situ hybridization (FISH) is a molecular method that allows the visualization and identification of single bacteria within tissue sections. In this study, we analyzed intestinal biopsy samples from five patients with possible HIS. All specimens yielded positive results by histopathological techniques. PCR amplification and sequencing of the 16S rRNA gene were performed. Sequences of two isolates clustered in the group of Brachyspira aalborgi, whereas in three cases, the sequences were highly similar to that of Brachyspira pilosicoli. Three phylotypes showed mismatches at distinct nucleotide positions with Brachyspira sp. sequences published previously. In addition, culture for Brachyspira was successful in three cases. On the basis of these data, we designed and evaluated a Brachyspira genus-specific 16S rRNA-directed FISH probe that detects all of the Brachyspira spp. published to date. FISH of biopsy samples resulted in strong, unequivocal signals of brush-like formations at the crypt surfaces. This technique allowed simultaneous visualization of single spirochetes and their identification as Brachyspira spp. In conclusion, FISH provides a fast and accurate technique for the visualization and identification of intestinal spirochetes in tissue sections. It therefore represents a valuable tool for routine diagnosis of HIS.

Schmiedel, Dinah; Epple, Hans-Jorg; Loddenkemper, Christoph; Ignatius, Ralf; Wagner, Jutta; Hammer, Bettina; Petrich, Annett; Stein, Harald; Gobel, Ulf B.; Schneider, Thomas; Moter, Annette

2009-01-01

304

Anaerobic metabolism of 1-amino-2-naphthol-based azo dyes (Sudan dyes) by human intestinal microflora.  

PubMed

The rates of metabolism of Sudan I and II and Para Red by human intestinal microflora were high compared to those of Sudan III and IV under anaerobic conditions. Metabolites of the dyes were identified as aniline, 2,4-dimethylaniline, o-toluidine, and 4-nitroaniline through high-performance liquid chromatography and liquid chromatography electrospray ionization tandem mass spectrometry analyses. These data indicate that human intestinal bacteria are able to reduce Sudan dyes to form potentially carcinogenic aromatic amines. PMID:17933925

Xu, Haiyan; Heinze, Thomas M; Chen, Siwei; Cerniglia, Carl E; Chen, Huizhong

2007-12-01

305

Inhibition of Intestinal Cholesterol Absorption by Ezetimibe in Humans  

Microsoft Academic Search

Background—Ezetimibe has been shown to inhibit cholesterol absorption in animal models, but studies on cholesterol absorption in humans have not been performed thus far. Methods and Results—The effect of ezetimibe (10 mg\\/d) on cholesterol absorption and synthesis, sterol excretion, and plasma concentrations of cholesterol and noncholesterol sterols was investigated in a randomized, double-blind, placebo-controlled, crossover study in 18 patients with

Thomas Sudhop; Dieter Lütjohann; Annette Kodal; Michael Igel; Diane L. Tribble; Sukrut Shah; Inna Perevozskaya; Klaus von Bergmann

306

Prediction of Bacterial microRNAs and possible targets in human cell transcriptome.  

PubMed

Recent studies have examined gene transfer from bacteria to humans that would result in vertical inheritance. Bacterial DNA appears to integrate into the human somatic genome through an RNA intermediate, and such integrations are detected more frequently in tumors than normal samples and in RNA than DNA samples. Also, vertebrate viruses encode products that interfere with the RNA silencing machinery, suggesting that RNA silencing may indeed be important for antiviral responses in vertebrates. RNA silencing in response to virus infection could be due to microRNAs encoded by either the virus or the host. We hypothesized that bacterial expression of RNA molecules with secondary structures is potentially able to generate miRNA molecules that can interact with the human host mRNA during bacterial infection. To test this hypothesis, we developed a pipelinebased bioinformatics approach to identify putative micro-RNAs derived from bacterial RNAs that may have the potential to regulate gene expression of the human host cell. Our results suggest that 68 bacterial RNAs predicted from 37 different bacterial genomes have predicted secondary structures potentially able to generate putative microRNAs that may interact with messenger RNAs of genes involved in 47 different human diseases. As an example, we examined the effect of transfecting three putative microRNAs into human embryonic kidney 293 (HEK293) cells. The results show that the bacterially derived microRNA sequence can significantly regulate the expression of the respective target human gene. We suggest that the study of these predicted microRNAs may yield important clues as to how the human host cell processes involved in human diseases like cancer, diabetes, rheumatoid arthritis, and others may respond to a particular bacterial environment. PMID:24871974

Shmaryahu, Amir; Carrasco, Margarita; Valenzuela, Pablo D T

2014-06-01

307

Survival and quality of halibut larvae ( Hippoglossus hippoglossus L.) in intensive farming: Possible impact of the intestinal bacterial community  

Microsoft Academic Search

The high mortality commonly observed during the early life stages of intensively reared halibut (Hippoglossus hippoglossus L) is believed to be caused by e.g. opportunistic bacteria. However, the impact of particular bacterial species is poorly defined and still remains disputable. The study describes the bacterial diversity in the gastrointestinal tract of halibut larvae in a large number of incubators at

Rannveig Bjornsdottir; Jonina Johannsdottir; Jennifer Coe; Heiddis Smaradottir; Thorleifur Agustsson; Sjofn Sigurgisladottir; Bjarnheidur K. Gudmundsdottir

2009-01-01

308

Ricin crosses polarized human intestinal cells and intestines of ricin-gavaged mice without evident damage and then disseminates to mouse kidneys.  

PubMed

Ricin is a potent toxin found in the beans of Ricinus communis and is often lethal for animals and humans when aerosolized or injected and causes significant morbidity and occasional death when ingested. Ricin has been proposed as a bioweapon because of its lethal properties, environmental stability, and accessibility. In oral intoxication, the process by which the toxin transits across intestinal mucosa is not completely understood. To address this question, we assessed the impact of ricin on the gastrointestinal tract and organs of mice after dissemination of toxin from the gut. We first showed that ricin adhered in a specific pattern to human small bowel intestinal sections, the site within the mouse gut in which a variable degree of damage has been reported by others. We then monitored the movement of ricin across polarized human HCT-8 intestinal monolayers grown in transwell inserts and in HCT-8 cell organoids. We observed that, in both systems, ricin trafficked through the cells without apparent damage until 24 hours post intoxication. We delivered a lethal dose of purified fluorescently-labeled ricin to mice by oral gavage and followed transit of the toxin from the gastrointestinal tracts to the internal organs by in vivo imaging of whole animals over time and ex vivo imaging of organs at various time points. In addition, we harvested organs from unlabeled ricin-gavaged mice and assessed them for the presence of ricin and for histological damage. Finally, we compared serum chemistry values from buffer-treated versus ricin-intoxicated animals. We conclude that ricin transverses human intestinal cells and mouse intestinal cells in situ prior to any indication of enterocyte damage and that ricin rapidly reaches the kidneys of intoxicated mice. We also propose that mice intoxicated orally with ricin likely die from distributive shock. PMID:23874986

Flora, Alyssa D; Teel, Louise D; Smith, Mark A; Sinclair, James F; Melton-Celsa, Angela R; O'Brien, Alison D

2013-01-01

309

Mechanisms underlying modulation of monocarboxylate transporter 1 (MCT1) by somatostatin in human intestinal epithelial cells  

PubMed Central

Somatostatin (SST), an important neuropeptide of the gastrointestinal tract has been shown to stimulate sodium chloride absorption and inhibit chloride secretion in the intestine. However, the effects of SST on luminal butyrate absorption in the human intestine have not been investigated. Earlier studies from our group and others have shown that monocarboxylate transporter (MCT1) plays an important role in the transport of butyrate in the human intestine. The present studies were undertaken to examine the effects of SST on butyrate uptake utilizing postconfluent human intestinal epithelial Caco2 cells. Apical SST treatment of Caco-2 cells for 30–60 min significantly increased butyrate uptake in a dose-dependent manner with maximal increase at 50 nM (?60%, P < 0.05). SST receptor 2 agonist, seglitide, mimicked the effects of SST on butyrate uptake. SST-mediated stimulation of butyrate uptake involved the p38 MAP kinase-dependent pathway. Kinetic studies demonstrated that SST increased the maximal velocity (Vmax) of the transporter by approximately twofold without any change in apparent Michaelis-Menten constant (Km). The higher butyrate uptake in response to SST was associated with an increase in the apical membrane levels of MCT1 protein parallel to a decrease in the intracellular MCT1 pool. MCT1 has been shown to interact specifically with CD147 glycoprotein/chaperone to facilitate proper expression and function of MCT1 at the cell surface. SST significantly enhanced the membrane levels of CD147 as well as its association with MCT1. This association was completely abolished by the specific p38 MAP kinase inhibitor, SB203580. Our findings demonstrate that increased MCT1 association with CD147 at the apical membrane in response to SST is p38 MAP kinase dependent and underlies the stimulatory effects of SST on butyrate uptake.

Theegala, Saritha; Bansal, Nikhil; Gill, Ravinder K.; Tyagi, Sangeeta; Alrefai, Waddah A.; Ramaswamy, Krishnamurthy; Dudeja, Pradeep K.

2009-01-01

310

Bacterial infection transmitted by human tissue allograft transplantation  

Microsoft Academic Search

Bacterial contamination of tissue allografts obtained from cadaveric donors has been a serious cause of morbidity and mortality\\u000a in recipients. Recent cases of fatal and nonfatal bacterial infections in recipients of contaminated articular cartilage (distal\\u000a femur) and tendon allografts have called attention to the importance of avoiding tissue donors suspected of carrying infectious\\u000a disease, of not processing donated tissue carrying

Ted Eastlund

2006-01-01

311

Colonization resistance of the human intestinal microflora: testing the hypothesis in normal volunteers.  

PubMed

Colonization resistance is the mechanism whereby the intestinal microflora protects itself against incursion by new and often harmful microorganisms. Some authors have claimed that colonization resistance is related to the integrity of the anaerobic flora, but this point has not been established in humans. In previous studies in our laboratory cefoxitin, piperacillin, cefoperazone or aztreonam were administered intravenously to healthy volunteers in order to study changes in the intestinal flora and acquisition of new strains. Seven of 16 antibiotic-treated subjects were colonized with gram-negative bacilli, but no correlation was observed between this colonization and the suppression of either anaerobes or any other component of the fecal flora. Marked strains of Escherichia coli and Pseudomonas aeruginosa were also administered by mouth in order to test acquisition of new bacteria. The fed bacteria were found in the stools of both antibiotic-treated and control subjects; the antibiotics had no apparent influence on the ability of these strains to colonize the intestinal tract. Our work, along with findings of others, supports the concept that colonization resistance occurs in humans and is diminished by antibiotic administration. However, it does not support the hypothesis that colonization resistance is related to the anaerobic microflora. PMID:3132394

Gorbach, S L; Barza, M; Giuliano, M; Jacobus, N V

1988-02-01

312

RELATIONSHIP OF HOST ANTIBODY TO FLUCTUATIONS OF ESCHERICHIA COLI SEROTYPES IN THE HUMAN INTESTINE1  

PubMed Central

Robinet, Harriette G. (Walter Reed Army Institute of Research, Washington, D.C.). Relationship of host antibody to fluctuations of Escherichia coli serotypes in the human intestine. J. Bacteriol. 84:896–901 1962.—A study was undertaken to determine the relationship of host antibody to the changes which take place among Escherichia coli serotypes present in the intestine. A survey of six healthy persons examined for E. coli monthly for 6 months reaffirmed the periodic fluctuations of antigenic types. Serotypes were studied from each individual and their appearance and maintenance or disappearance closely followed. Representative strains were chosen each month and used to prepare a heated sodium hydroxide lipopolysaccharide extract for sensitizing human group O Rh-negative red blood cells for the hemagglutination test. These antigens were tested with the sera drawn from each of the six individuals at the time monthly cultures were made. Results showed that antibody levels for each serotype remained basically constant over the 6-month period. Titer levels tended to be characteristic of the host rather than related to the E. coli bacteria, as shown by tests with serotypes both from the individual's own intestinal tract and from other individuals in the study. High normal antibody levels for autologous E. coli serotypes did not act as a deterrent to the ability of the organisms to establish themselves in the bowel, nor did antibody titer for E. coli strains determine whether they would continue as residents over several months or depart as transient flora.

Robinet, Harriette G.

1962-01-01

313

Otilonium bromide inhibits calcium entry through L-type calcium channels in human intestinal smooth muscle.  

PubMed

Otilonium bromide (OB) is used as an intestinal antispasmodic. The mechanism of action of OB is not completely understood. As Ca(2+) entry into intestinal smooth muscle is required to trigger contractile activity, our hypothesis was that OB blocked Ca(2+) entry through L-type Ca(2+) channels. Our aim was to determine the effects of OB on Ca(2+), Na(+) and K(+) ion channels in human jejunal circular smooth muscle cells and on L-type Ca(2+) channels expressed heterologously in HEK293 cells. Whole cell currents were recorded using standard patch clamp techniques. Otilonium bromide (0.09-9 micromol L(-1)) was used as this reproduced clinical intracellular concentrations. In human circular smooth muscle cells, OB inhibited L-type Ca(2+) current by 25% at 0.9 micromol L(-1) and 90% at 9 micromol L(-1). Otilonium bromide had no effect on Na(+) or K(+) currents. In HEK293 cells, 1 micromol L(-1) OB significantly inhibited the expressed L-type Ca(2+) channels. Truncation of the alpha(1C) subunit C and N termini did not block the inhibitory effects of OB. Otilonium bromide inhibited Ca(2+) entry through L-type Ca(2+) at concentrations similar to intestinal tissue levels. This effect may underlie the observed muscle relaxant effects of the drug. PMID:15086870

Strege, P R; Evangelista, S; Lyford, G L; Sarr, M G; Farrugia, G

2004-04-01

314

The immunohistochemical demonstration of chymase and tryptase in human intestinal mast cells.  

PubMed

An immunohistochemical double-labelling technique for the simultaneous identification of mast cells containing tryptase alone (MCT) or chymase together with tryptase (MCTC) was evaluated quantitatively using two monoclonal antibodies, mAb 1222A (antitryptase) and mAb 1254B (antichymase). Saturation conditions were established for the binding of the antibodies to the mast cell enzymes by counting labelled mast cells in consecutive sections of normal human intestine incubated with serial dilutions of the antibodies. When, under such conditions, the antitryptase was applied after saturation with mAb 1254B, the reproducibility of the double-labelling procedure was excellent. MCT were located preferentially in the intestinal mucosa but, in contrast to what has previously been reported, they were not the predominant type of mast cell at this site. The percentage of MCT of the total number of immunopositive mast cells varied considerably in the colonic mucosa (7-67%, average 30%), while this was not the case in the small intestinal mucosa (5-26%, average 10%). Mast cell chymase, unlike tryptase, was not recognized by the antichymase antibody after aldehyde fixation and a higher apparent fraction of MCT therefore occurred after double labelling. These findings suggest that the proteinase composition of human mast cells, unlike that of murine mast cells, should not be taken as evidence of phenotypic heterogeneity. Taken together with previous observations, they suggest instead that the lack of chymase may be related to functional activity or stage of maturation of the mast cells. PMID:7960936

Aldenborg, F; Enerbäck, L

1994-07-01

315

Comparison of the one-gram d -[ 14 C]xylose breath test to the [ 14 C]bile acid breath test in patients with small-intestine bacterial overgrowth  

Microsoft Academic Search

In twelve patients with culture-proven bacterial overgrowth of the small intestine, the ability of a newly-developed one-gramd-[14C]xylose breath test to detect bacterial overgrowth was compared to that of the [14C]bile acid breath test. All patients manifested excessive production of breath14CO2 after the administration of one gram [14C]xylose, with 83% of the patients being abnormal within the first hour of testing.

Charles E. King; Phillip P. Toskes; Tomas R. Guilarte; Erhard Lorenz; Susan L. Welkos

1980-01-01

316

Molecular and histological identification of the acanthocephalan Bolbosoma cf. capitatum from the human small intestine.  

PubMed

Acanthocephalans of the genus Bolbosoma are intestinal parasites of marine mammals with a lifecycle similar to that of anisakid nematodes. Several cases of Bolbosoma infection in humans have been reported, but no species identification has been made. Here, we report a case of Bolbosoma infection, in which the worm was found in histological sections of the partially resected small intestine of a Japanese man. Morphological features of the worm reconstructed from serial sectioning indicated that the worm was most likely to be a sexually immature female of Bolbosoma capitatum. DNA extraction from paraffin-embedded sections and ITS1-5.8S rRNA-ITS2 sequencing showed that this species formed a monophyletic group with Bolbosoma nipponicum, and was clearly distinguishable from Corynosoma spp. or Polymorphus spp. These results may provide a reference for identifying and characterizing unknown acanthocephalans found in histological sections. PMID:22634485

Arizono, Naoki; Kuramochi, Toshiaki; Kagei, Noboru

2012-12-01

317

Vasoactive Intestinal Peptide Inhibits Human Small-Cell Lung Cancer Proliferation in vitro and in vivo  

NASA Astrophysics Data System (ADS)

Small-cell lung carcinoma (SCLC) is an aggressive, rapidly growing and metastasizing, and highly fatal neoplasm. We report that vasoactive intestinal peptide inhibits the proliferation of SCLC cells in culture and dramatically suppresses the growth of SCLC tumor-cell implants in athymic nude mice. In both cases, the inhibition was mediated apparently by a cAMP-dependent mechanism, because the inhibition was enhanced by the adenylate cyclase activator forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine in proportion to increases in intracellular cAMP levels, and the inhibition was abolished by selective inhibition of cAMP-dependent protein kinase. If confirmed in clinical trials, this antiproliferative action of vasoactive intestinal peptide may offer a new and promising means of suppressing SCLC in human subjects, without the toxic side effects of chemotherapeutic agents.

Maruno, Kaname; Absood, Afaf; Said, Sami I.

1998-11-01

318

Stereospecific Biotransformation of Dihydrodaidzein into (3S)-Equol by the Human Intestinal Bacterium Eggerthella Strain Julong 732?  

PubMed Central

Stereochemical course of isoflavanone dihydrodaidzein (DHD) reduction into the isoflavan (3S)-equol via tetrahydrodaidzein (THD) by the human intestinal anaerobic bacterium Eggerthella strain Julong 732 was studied. THD was synthesized by catalytic hydrogenation, and each stereoisomer was separated by chiral high-performance liquid chromatography. Circular dichroism spectroscopy was used to elucidate the absolute configurations of four synthetic THD stereoisomers. Rapid racemization of DHD catalyzed by Julong 732 prevented the substrate stereospecificity in the conversion of DHD into THD from being confirmed. The absolute configuration of THD, prepared by reduction of DHD in the cell-free incubation, was assigned as (3R,4S) via comparison of the retention time to that of the authentic THD by chiral chromatography. Dehydroequol (DE) was unable to produce the (3S)-equol both in the cell-free reaction and in the bacterial transformation, negating the possible intermediacy of DE. Finally, the intermediate (3R,4S)-THD was reduced into (3S)-equol by the whole cell, indicating the inversion of stereochemistry at C-3 during the reduction. A possible mechanism accounting for the racemization of DHD and the inversion of configuration of THD during reduction into (3S)-equol is proposed.

Kim, Mihyang; Kim, Su-Il; Han, Jaehong; Wang, Xiu-Ling; Song, Dae-Geun; Kim, Soo-Un

2009-01-01

319

Stereospecific biotransformation of dihydrodaidzein into (3S)-equol by the human intestinal bacterium Eggerthella strain Julong 732.  

PubMed

Stereochemical course of isoflavanone dihydrodaidzein (DHD) reduction into the isoflavan (3S)-equol via tetrahydrodaidzein (THD) by the human intestinal anaerobic bacterium Eggerthella strain Julong 732 was studied. THD was synthesized by catalytic hydrogenation, and each stereoisomer was separated by chiral high-performance liquid chromatography. Circular dichroism spectroscopy was used to elucidate the absolute configurations of four synthetic THD stereoisomers. Rapid racemization of DHD catalyzed by Julong 732 prevented the substrate stereospecificity in the conversion of DHD into THD from being confirmed. The absolute configuration of THD, prepared by reduction of DHD in the cell-free incubation, was assigned as (3R,4S) via comparison of the retention time to that of the authentic THD by chiral chromatography. Dehydroequol (DE) was unable to produce the (3S)-equol both in the cell-free reaction and in the bacterial transformation, negating the possible intermediacy of DE. Finally, the intermediate (3R,4S)-THD was reduced into (3S)-equol by the whole cell, indicating the inversion of stereochemistry at C-3 during the reduction. A possible mechanism accounting for the racemization of DHD and the inversion of configuration of THD during reduction into (3S)-equol is proposed. PMID:19304836

Kim, Mihyang; Kim, Su-Il; Han, Jaehong; Wang, Xiu-Ling; Song, Dae-Geun; Kim, Soo-Un

2009-05-01

320

Tea Catechin Auto-oxidation Dimers are Accumulated and Retained by Caco-2 Human Intestinal Cells  

PubMed Central

Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers [theasinensins (THSNs) and P-2 analogs) were quantified in commercial teas by HPLC-MS. (?)-Epigallocatechin (EGC) and (?)-epigallocatechin gallate (EGCG) homodimers were present at 10–43 and 0–62 µmol/g leaf, respectively. EGC-EGCG heterodimers were present at 0–79 µmol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three h accumulation of EGC and EGCG was 0.19– 0.55% and 1.24–1.35% respectively. Comparatively, 3h accumulation of the EGC P-2 analog, and THSNs C/E was 0.89 ± 0.28% and 1.53 ± 0.36%. Accumulation of P-2, and THSNs A/D was 6.93 ± 2.1%, and 10.1 ± 3.6%. EGCG-EGC heterodimer P-2 analog, and THSN B 3h accumulation was 4.87 ± 2.2%, and 4.65 ± 2.8% respectively. One h retention of P-2, and THSNs A/D was 171 ± 22%, and 29.6 ± 9.3% of accumulated amount suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium.

Neilson, Andrew P.; Song, Brian J.; Sapper, Teryn N.; Bomser, Joshua A.; Ferruzzi, Mario G.

2010-01-01

321

A distinct array of proinflammatory cytokines is expressed in human colon epithelial cells in response to bacterial invasion.  

PubMed Central

Pathogenic bacteria that penetrate the intestinal epithelial barrier stimulate an inflammatory response in the adjacent intestinal mucosa. The present studies asked whether colon epithelial cells can provide signals that are important for the initiation and amplification of an acute mucosal inflammatory response. Infection of monolayers of human colon epithelial cell lines (T84, HT29, Caco-2) with invasive strains of bacteria (Salmonella dublin, Shigella dysenteriae, Yersinia enterocolitica, Listeria monocytogenes, enteroinvasive Escherichia coli) resulted in the coordinate expression and upregulation of a specific array of four proinflammatory cytokines, IL-8, monocyte chemotactic protein-1, GM-CSF, and TNF alpha, as assessed by mRNA levels and cytokine secretion. Expression of the same cytokines was upregulated after TNF alpha or IL-1 stimulation of these cells. In contrast, cytokine gene expression was not altered after infection of colon epithelial cells with noninvasive bacteria or the noninvasive protozoan parasite, G. lamblia. Notably, none of the cell lines expressed mRNA for IL-2, IL-4, IL-5, IL-6, IL-12p40, IFN-gamma, or significant levels of IL-1 or IL-10 in response to the identical stimuli. The coordinate expression of IL-8, MCP-1, GM-CSF and TNF alpha appears to be a general property of human colon epithelial cells since an identical array of cytokines, as well as IL-6, also was expressed by freshly isolated human colon epithelial cells. Since the cytokines expressed in response to bacterial invasion or other proinflammatory agonists have a well documented role in chemotaxis and activation of inflammatory cells, colon epithelial cells appear to be programmed to provide a set of signals for the activation of the mucosal inflammatory response in the earliest phases after microbial invasion. Images

Jung, H C; Eckmann, L; Yang, S K; Panja, A; Fierer, J; Morzycka-Wroblewska, E; Kagnoff, M F

1995-01-01

322

Transport of thalidomide by the human intestinal caco-2 monolayers.  

PubMed

Studies in patients have indicated that the oral absorption of thalidomide is considerably variable at high doses (>200 mg/day). The aim of this study was to investigate the transport of racemic thalidomide using human colon cancer cell line (Caco-2) monolayers, which have been widely used to investigate drug permeability. A typical 21-day protocol was used to prepare Caco-2 monolayers. Thalidomide was determined by a validated high performance liquid chromatography method with ultraviolet detection. The integrity of Caco-2 monolayer was confirmed when the transepithelial electrical resistance (TEER) exceeded 300 Ohmz . cm2, and the leakage of 14C-manitol was <1% per hour. Uptake of thalidomide by Caco-2 cells was very limited (up to 2.1%). The transport of thalidomide appeared to be linear up to 1 hr. Our study indicated that the permeability coefficients (Papp) of thalidomide at 2.5-300 microM from the apical (AP) to basolateral (BL) and from BL to AP side was 2-6 x 10(-5) cm/sec, with a marked decrease in Papp values from AP to BL at increased thalidomide concentration. The transport of thalidomide was sodium-, temperature- and pH-dependent, as replacement of extracellular sodium chloride or reducing temperature and apical pH can result in significant decreases in the Papp values. Additional data indicated that transport of thalidomide is energy-dependent, as it was significantly (P < 0.05) inhibited by the ATP inhibitors, sodium azide and 2,4-dinitrophenol. In addition, DL-glutamic acid, cytidine, diprodomole, papaverine, quinidine, and cyclophosphamide significantly (P < 0.05) inhibited the transport of thalidomide, while the P-glycoprotein inhibitor verapamil and other nucleosides and nucleotides such as thymidine and guanine had no effect. These results indicated that thalidomide was rapidly transported by Caco-2 monolayers, and this might involve a saturable energy-dependent transporter. PMID:16010862

Zhou, Shufeng; Li, Yan; Kestell, Phillip; Schafer, Peter; Chan, Eli; Paxton, James W

2005-01-01

323

Human gut-on-a-chip inhabited by microbial flora that experiences intestinal peristalsis-like motions and flow.  

PubMed

Development of an in vitro living cell-based model of the intestine that mimics the mechanical, structural, absorptive, transport and pathophysiological properties of the human gut along with its crucial microbial symbionts could accelerate pharmaceutical development, and potentially replace animal testing. Here, we describe a biomimetic 'human gut-on-a-chip' microdevice composed of two microfluidic channels separated by a porous flexible membrane coated with extracellular matrix (ECM) and lined by human intestinal epithelial (Caco-2) cells that mimics the complex structure and physiology of living intestine. The gut microenvironment is recreated by flowing fluid at a low rate (30 ?L h(-1)) producing low shear stress (0.02 dyne cm(-2)) over the microchannels, and by exerting cyclic strain (10%; 0.15 Hz) that mimics physiological peristaltic motions. Under these conditions, a columnar epithelium develops that polarizes rapidly, spontaneously grows into folds that recapitulate the structure of intestinal villi, and forms a high integrity barrier to small molecules that better mimics whole intestine than cells in cultured in static Transwell models. In addition, a normal intestinal microbe (Lactobacillus rhamnosus GG) can be successfully co-cultured for extended periods (>1 week) on the luminal surface of the cultured epithelium without compromising epithelial cell viability, and this actually improves barrier function as previously observed in humans. Thus, this gut-on-a-chip recapitulates multiple dynamic physical and functional features of human intestine that are critical for its function within a controlled microfluidic environment that is amenable for transport, absorption, and toxicity studies, and hence it should have great value for drug testing as well as development of novel intestinal disease models. PMID:22434367

Kim, Hyun Jung; Huh, Dongeun; Hamilton, Geraldine; Ingber, Donald E

2012-06-21

324

PXR/CYP3A4-humanized mice for studying drug-drug interactions involving intestinal P-glycoprotein  

PubMed Central

Rodent models are less suitable for predicting drug-drug interactions at the level of the human intestinal mucosa, especially when nuclear receptors like pregnane X receptor (PXR) are involved. Recently, a transgenic mouse model, expressing both human PXR and CYP3A4, was developed and shown to be a better predictor of CYP3A4 induction by xenobiotics in humans as compared to wild-type mice. In the present study, we tested the hypothesis that this mouse model can also predict PXR-mediated induction of intestinal P-gp in humans. By use of the in situ intestinal perfusion technique with mesenteric blood sampling, the effect of oral rifampicin treatment on intestinal permeability for the HIV protease inhibitor darunavir, a dual CYP3A4/P-gp substrate, was investigated. Rifampicin treatment lowered the intestinal permeability for darunavir by 50 % compared to non-treated mice. The P-gp inhibitor GF120918 increased the permeability for darunavir by 400 % in rifampicin-treated mice, while this was only 56 % in mice that were not treated, thus indicating P-gp induction by rifampicin. The non-specific P450 inhibitor aminobenzotriazole (100 ?M) did not affect the permeability for darunavir. Quantitative Western blot analysis of the intestinal tissue showed that rifampicin treatment induced intestinal P-gp levels four-fold, while CYP3A4 levels remained unchanged. Oral co-administration of rifampicin with the phytochemical sulforaphane for three days increased the permeability for darunavir by 50 % compared to rifampicin treatment alone. These data show that PXR/CYP3A4-humanized mice can be used to study the inducing effects of xenobiotics on intestinal P-gp.

Holmstock, Nico; Gonzalez, Frank J.; Baes, Myriam; Annaert, Pieter; Augustijns, Patrick

2013-01-01

325

Tumor Necrosis Factor Alpha Is a Key Mediator of Gut Inflammation Seen in Amebic Colitis in Human Intestine in the SCID Mouse-Human Intestinal Xenograft Model of Disease  

Microsoft Academic Search

Received 24 January 2003\\/Returned for modification 21 February 2003\\/Accepted 6 June 2003 We used Entamoeba histolytica infection in human intestinal xenografts to study the roles interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-) in the pathogenesis of amebic colitis. We found that blockade of TNF- reduced inflammation and intestinal damage in amebic infection, while inhibition of IL-1 reduced cytokine production

Zhi Zhang; Sajan Mahajan; Xiaochung Zhang; Samuel L. Stanley

2003-01-01

326

Vancomycin-resistant Enterococcus domination of intestinal microbiota is enabled by antibiotic treatment in mice and precedes bloodstream invasion in humans.  

PubMed

Bloodstream infection by highly antibiotic-resistant bacteria, such as vancomycin-resistant Enterococcus (VRE), is a growing clinical problem that increasingly defies medical intervention. Identifying patients at high risk for bacterial sepsis remains an important clinical challenge. Recent studies have shown that antibiotics can alter microbial diversity in the intestine. Here, we characterized these effects using 16s rDNA pyrosequencing and demonstrated that antibiotic treatment of mice enabled exogenously administered VRE to efficiently and nearly completely displace the normal microbiota of the small and large intestine. In the clinical setting, we found that intestinal domination by VRE preceded bloodstream infection in patients undergoing allogeneic hematopoietic stem cell transplantation. Our results demonstrate that antibiotics perturb the normal commensal microbiota and set the stage for intestinal domination by bacteria associated with hospital-acquired infections. Thus, high-throughput DNA sequencing of the intestinal microbiota could identify patients at high risk of developing bacterial sepsis. PMID:21099116

Ubeda, Carles; Taur, Ying; Jenq, Robert R; Equinda, Michele J; Son, Tammy; Samstein, Miriam; Viale, Agnes; Socci, Nicholas D; van den Brink, Marcel R M; Kamboj, Mini; Pamer, Eric G

2010-12-01

327

Mast cell expression of the serotonin1A receptor in guinea pig and human intestine  

PubMed Central

Serotonin [5-hydroxytryptamine (5-HT)] is released from enterochromaffin cells in the mucosa of the small intestine. We tested a hypothesis that elevation of 5-HT in the environment of enteric mast cells might degranulate the mast cells and release mediators that become paracrine signals to the enteric nervous system, spinal afferents, and secretory glands. Western blotting, immunofluorescence, ELISA, and pharmacological analysis were used to study expression of 5-HT receptors by mast cells in the small intestine and action of 5-HT to degranulate the mast cells and release histamine in guinea pig small intestine and segments of human jejunum discarded during Roux-en-Y gastric bypass surgeries. Mast cells in human and guinea pig preparations expressed the 5-HT1A receptor. ELISA detected spontaneous release of histamine in guinea pig and human preparations. The selective 5-HT1A receptor agonist 8-hydroxy-PIPAT evoked release of histamine. A selective 5-HT1A receptor antagonist, WAY-100135, suppressed stimulation of histamine release by 5-HT or 8-hydroxy-PIPAT. Mast cell-stabilizing drugs, doxantrazole and cromolyn sodium, suppressed the release of histamine evoked by 5-HT or 8-hydroxy-PIPAT in guinea pig and human preparations. Our results support the hypothesis that serotonergic degranulation of enteric mast cells and release of preformed mediators, including histamine, are mediated by the 5-HT1A serotonergic receptor. Association of 5-HT with the pathophysiology of functional gastrointestinal disorders (e.g., irritable bowel syndrome) underlies a question of whether selective 5-HT1A receptor antagonists might have therapeutic application in disorders of this nature.

Wang, Guo-Du; Wang, Xi-Yu; Zou, Fei; Qu, Meihua; Liu, Sumei; Fei, Guijun; Xia, Yun; Needleman, Bradley J.; Mikami, Dean J.

2013-01-01

328

Human intestinal parasites in non-biting synanthropic flies in Ogun State, Nigeria.  

PubMed

Filth-feeding and breeding, non-biting synanthropic flies have been incriminated in the dissemination of human enteropathogens in the environment. This study determined the species of non-biting synanthropic flies associated with four filthy sites in Ilishan, Ogun State, southwest Nigeria, and assessed their potentials for mechanical transmission of human intestinal parasites. 7190 flies identified as Musca domestica (33.94%), Chrysomya megacephala (26.01%), Musca sorbens (23.23%), Lucilia cuprina (8.76%), Calliphora vicina (4.59%), Sarcophaga sp. (2.78%) and Fannia scalaris (0.70%) were examined for human intestinal parasites by the formol-ether concentration and modified Ziehl-Neelsen techniques. Eggs of the following parasites: Ascaris lumbricoides (34.08%), Trichuris trichiura (25.87%), hookworms (20.45%), Taenia sp. (2.36%), Hymenolepis nana (1.11%), Enterobius vermicularis (0.56%), Strongyloides stercoralis (larvae; 3.89%) and cysts of Entamoeba histolytica/dispar (27.26%), Entamoeba coli (22.67%), Giardia lamblia (3.34%) and Cryptosporidium sp. (1.81%) were isolated from the body surfaces and or gut contents of 75.24% of 719 pooled fly batches. The helminths A. lumbricoides and T. trichiura and the protozoans, E. histolytica/dispar and E. coli were the dominant parasites detected, both on body surfaces and in the gut contents of flies. C. megacephala was the highest carrier of parasites (diversity and number). More parasites were isolated from the gut than from body surfaces (P < 0.05). Flies from soiled ground often carried more parasites than those from abattoir, garbage or open-air market. Synanthropic fly species identified in this study can be of potential epidemiological importance as mechanical transmitters of human intestinal parasites acquired naturally from filth and carried on their body surfaces and or in the gut, because of their vagility and feeding mechanisms. PMID:23290716

Adenusi, Adedotun Adesegun; Adewoga, Thomas O Sunday

2013-01-01

329

Lineage-Specific Expression of Bestrophin-2 and Bestrophin-4 in Human Intestinal Epithelial Cells  

PubMed Central

Intestinal epithelial cells (IECs) regulate the absorption and secretion of anions, such as HCO3- or Cl-. Bestrophin genes represent a newly identified group of calcium-activated Cl- channels (CaCCs). Studies have suggested that, among the four human bestrophin-family genes, bestrophin-2 (BEST2) and bestrophin-4 (BEST4) might be expressed within the intestinal tissue. Consistently, a study showed that BEST2 is expressed by human colonic goblet cells. However, their precise expression pattern along the gastrointestinal tract, or the lineage specificity of the cells expressing these genes, remains largely unknown. Here, we show that BEST2 and BEST4 are expressed in vivo, each in a distinct, lineage-specific manner, in human IECs. While BEST2 was expressed exclusively in colonic goblet cells, BEST4 was expressed in the absorptive cells of both the small intestine and the colon. In addition, we found that BEST2 expression is significantly down-regulated in the active lesions of ulcerative colitis, where goblet cells were depleted, suggesting that BEST2 expression is restricted to goblet cells under both normal and pathologic conditions. Consistently, the induction of goblet cell differentiation by a Notch inhibitor, LY411575, significantly up-regulated the expression of not BEST4 but BEST2 in MUC2-positive HT-29 cells. Conversely, the induction of absorptive cell differentiation up-regulated the expression of BEST4 in villin-positive Caco-2 cells. In addition, we found that the up- or down-regulation of Notch activity leads to the preferential expression of either BEST4 or BEST2, respectively, in LS174T cells. These results collectively confirmed that BEST2 and BEST4 could be added to the lineage-specific genes of humans IECs due to their abilities to clearly identify goblet cells of colonic origin and a distinct subset of absorptive cells, respectively.

Ito, Go; Okamoto, Ryuichi; Murano, Tatsuro; Shimizu, Hiromichi; Fujii, Satoru; Nakata, Toru; Mizutani, Tomohiro; Yui, Shiro; Akiyama-Morio, Junko; Nemoto, Yasuhiro; Okada, Eriko; Araki, Akihiro; Ohtsuka, Kazuo; Tsuchiya, Kiichiro; Nakamura, Tetsuya; Watanabe, Mamoru

2013-01-01

330

The majority of intestinal IgA+ and IgG+ plasmablasts in the human gut are antigen-specific  

PubMed Central

Mucosal antibody responses play a major role in mediating homeostasis with the intestinal flora. It has been suggested that imbalance in the IgA+ and IgG+ intestinal B cell repertoire may be associated with the development of diseases such as inflammatory bowel disease. Despite this, little is known about the antibody specificity of human intestinal plasmablasts. Here, we have determined the reactivity profile of single isolated IgA+ and IgG+ plasmablasts from human terminal ileum using antibody cloning and in vitro expression. We found that approximately 25% of intestinal IgA and IgG plasmablast antibodies were polyreactive; the majority were antigen-specific. Antigen specificity was not only directed against enteropathogenic microbes but also against commensal microbes and self antigens. Regardless of their reactivity, all intestinal antibodies were somatically mutated and showed signs of antigen-mediated selection, suggesting that they developed from antigen-specific B cell responses. Together, our data indicate that antigen-specific immune responses to intestinal microbes are largely responsible for the maintenance of intestinal homeostasis and thus provide a basis for understanding the deregulated immune responses observed in patients with inflammatory bowel disease.

Benckert, Julia; Schmolka, Nina; Kreschel, Cornelia; Zoller, Markus Josef; Sturm, Andreas; Wiedenmann, Bertram; Wardemann, Hedda

2011-01-01

331

Developmental changes in vasoactive intestinal polypeptide immunoreactivity in the human paravertebral ganglia.  

PubMed

Vasoactive intestinal polypeptide (VIP) belongs to the glucagon-secretin family of polypeptides and possesses numerous functions. Its existence in the mammalian central and peripheral nervous system has been widely documented. However, there are no reports on the developmental aspects of VIP-like immunoreactivity (VIP-IR) in the human postganglionic sympathetic neurons. In this study the availability and distribution of vasoactive intestinal polypeptide has been localized in human stellate ganglia neurons and nerve fibers from neonates, children and adults using the immunohistochemical method. In neonatal ganglia VIP-immunoreactive postganglionic neurons were revealed in a marked population compared to others age-groups. These nerve cells are both small and large in size and are distributed in small clusters or singly in the area of ganglia sections. In children, VIP-IR in ganglionic neurons decreases. In adult stellate ganglia, VIP-immunoreactive postganglionic neurons rarely occur. In ganglia of an individual human only varicosities of VIP-positive nerve fibers were observed. These results provide the age-dependent reduction of VIP-like immunoreactivity in human stellate ganglia neurons and suggest the different role of this peptide in the function of sympathetic ganglia neurons with age. PMID:10609054

Roudenok, V; Kühnel, W; Rogov, Y; Nerovnja, A

1999-12-01

332

Functional characterization of the human intestinal NaPi-IIb cotransporter in hamster fibroblasts and Xenopus oocytes  

Microsoft Academic Search

The recently cloned NaPi-IIb cotransporter is an apical membrane protein that is involved in the absorption of phosphate in the intestine. To expedite functional and structural studies, the human intestinal NaPi-IIb cotransporter was stably expressed in hamster fibroblast (PS120) cells. The hNaPi-IIb cDNA stably transfected cells exhibited a 1.8-fold higher sodium-dependent phosphate uptake than vector DNA transfected cells, and had

Hua Xu; Michael Inouye; Timothy Missey; James F Collins; Fayez K Ghishan

2002-01-01

333

Identification of NF-?B Modulation Capabilities within Human Intestinal Commensal Bacteria  

PubMed Central

The intestinal microbiota plays an important role in modulation of mucosal immune responses. To seek interactions between intestinal epithelial cells (IEC) and commensal bacteria, we screened 49 commensal strains for their capacity to modulate NF-?B. We used HT-29/kb-seap-25 and Caco-2/kb-seap-7 intestinal epithelial cells and monocyte-like THP-1 blue reporter cells to measure effects of commensal bacteria on cellular expression of a reporter system for NF-?B. Bacteria conditioned media (CM) were tested alone or together with an activator of NF-?B to explore its inhibitory potentials. CM from 8 or 10 different commensal species activated NF-?B expression on HT-29 and Caco-2 cells, respectively. On THP-1, CM from all but 5 commensal strains stimulated NF-?B. Upon challenge with TNF-? or IL-1?, some CM prevented induced NF-?B activation, whereas others enhanced it. Interestingly, the enhancing effect of some CM was correlated with the presence of butyrate and propionate. Characterization of the effects of the identified bacteria and their implications in human health awaits further investigations.

Lakhdari, Omar; Tap, Julien; Beguet-Crespel, Fabienne; Le Roux, Karine; de Wouters, Tomas; Cultrone, Antonietta; Nepelska, Malgorzata; Lefevre, Fabrice; Dore, Joel; Blottiere, Herve M.

2011-01-01

334

Specific-sized Hyaluronan Fragments Promote Expression of Human ?-Defensin 2 in Intestinal Epithelium*  

PubMed Central

Hyaluronan (HA) is a glycosaminoglycan polymer found in the extracellular matrix of virtually all mammalian tissues. Recent work has suggested a role for small, fragmented HA polymers in initiating innate defense responses in immune cells, endothelium, and epidermis through interaction with innate molecular pattern recognition receptors, such as TLR4. Despite these advances, little is known regarding the effect of fragmented HA at the intestinal epithelium, where numerous pattern recognition receptors act as sentinels of an innate defense response that maintains epithelial barrier integrity in the presence of abundant and diverse microbial challenges. Here we report that HA fragments promote expression of the innate antimicrobial peptide human ?-defensin 2 (H?D2) in intestinal epithelial cells. Treatment of HT-29 colonic epithelial cells with HA fragment preparations resulted in time- and dose-dependent up-regulated expression of H?D2 protein in a fragment size-specific manner, with 35-kDa HA fragment preparations emerging as the most potent inducers of intracellular H?D2. Furthermore, oral administration of specific-sized HA fragments promotes the expression of an H?D2 ortholog in the colonic epithelium of both wild-type and CD44-deficient mice but not in TLR4-deficient mice. Together, our observations suggest that a highly size-specific, TLR4-dependent, innate defense response to fragmented HA contributes to intestinal epithelium barrier defense through the induction of intracellular H?D2 protein.

Hill, David R.; Kessler, Sean P.; Rho, Hyunjin K.; Cowman, Mary K.; de la Motte, Carol A.

2012-01-01

335

Bacterial Urease and its Role in Long-Lasting Human Diseases  

PubMed Central

Urease is a virulence factor found in various pathogenic bacteria. It is essential in colonization of a host organism and in maintenance of bacterial cells in tissues. Due to its enzymatic activity, urease has a toxic effect on human cells. The presence of ureolytic activity is an important marker of a number of bacterial infections. Urease is also an immunogenic protein and is recognized by antibodies present in human sera. The presence of such antibodies is connected with progress of several long-lasting diseases, like rheumatoid arthritis, atherosclerosis or urinary tract infections. In bacterial ureases, motives with a sequence and/or structure similar to human proteins may occur. This phenomenon, known as molecular mimicry, leads to the appearance of autoantibodies, which take part in host molecules destruction. Detection of antibodies-binding motives (epitopes) in bacterial proteins is a complex process. However, organic chemistry tools, such as synthetic peptide libraries, are helpful in both, epitope mapping as well as in serologic investigations. In this review, we present a synthetic report on a molecular organization of bacterial ureases - genetic as well as structural. We characterize methods used in detecting urease and ureolytic activity, including techniques applied in disease diagnostic processes and in chemical synthesis of urease epitopes. The review also provides a summary of knowledge about a toxic effect of bacterial ureases on human body and about occurrence of anti-urease antibodies in long-lasting diseases.

Konieczna, Iwona; Zarnowiec, Paulina; Kwinkowski, Marek; Kolesinska, Beata; Fraczyk, Justyna; Kaminski, Zbigniew; Kaca, Wieslaw

2012-01-01

336

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host  

PubMed Central

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis.

Alaish, Samuel M.; Smith, Alexis D.; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P.; Cross, Alan S

2013-01-01

337

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host.  

PubMed

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis. PMID:23652772

Alaish, Samuel M; Smith, Alexis D; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P; Cross, Alan

2013-01-01

338

Assessment of enzymatic prodrug stability in human, dog and simulated intestinal fluids.  

PubMed

The aim of this study was to determine the stability of three ester prodrugs, chloramphenicol succinate, enalapril and candesartan cilexetil, in human proximal small intestinal fluid (HIF), dog proximal small intestinal fluids (DIF) and simulated intestinal fluid (FaSSIF), with the addition of pancreatin. The total protein content in the proximal jejunal fluids was determined in HIF and DIF, respectively. Candesartan cilexetil was significantly degraded in HIF (initial t(1/2(0-5 min))=5.4 ± 0.5 min) and in DIF (initial t(1/2(0-5 min))=5.7 ± 0.1 min), while chloramphenicol succinate and enalapril were stable in both media. The degradation of candesartan cilexetil was shown to be mediated by enzymes following Michaelis-Menten enzyme kinetics and was inhibited by addition of esterase inhibitors. The enzymatic capacity reflected by V(max) was 4-fold higher in DIF than in HIF and correlated to its 2-fold higher protein concentration. The degradation of candesartan cilexetil in the FaSSIF-pancreatin solution was slower (t(1/2)=207 ± 34 min) than the degradation in both HIF and DIF. Changing the pH to the enzyme optima or increasing the amount of pancreatin, increased the degradation rate of candesartan cilexetil, but not in the magnitude as in HIF. As a result, two in vitro models, based on in vivo intestinal fluids, were developed using candesartan cilexetil as a model drug. The DIF seems to be a reasonably good model for HIF, although the degradation capacity seems to be somewhat higher, possibly due to the higher enzyme concentration in DIF. Future investigations will develop novel enzymatic based in vitro models for rapid assessment and biopharmaceutical screening tools for prodrugs. PMID:22155764

Borde, A S; Karlsson, E M; Andersson, K; Björhall, K; Lennernäs, H; Abrahamsson, B

2012-04-01

339

Functional modulation of human intestinal epithelial cell responses by Bifidobacterium infantis and Lactobacillus salivarius  

PubMed Central

Intestinal epithelial cells (IECs) and dendritic cells (DCs) play a pivotal role in antigen sampling and the maintenance of gut homeostasis. However, the interaction of commensal bacteria with the intestinal surface remains incompletely understood. Here we investigated immune cell responses to commensal and pathogenic bacteria. HT-29 human IECs were incubated with Bifidobacterium infantis 35624, Lactobacillus salivarius UCC118 or Salmonella typhimurium UK1 for varying times, or were pretreated with a probiotic for 2 hr prior to stimulation with S. typhimurium or flagellin. Gene arrays were used to examine inflammatory gene expression. Nuclear factor (NF)-?B activation, interleukin (IL)-8 secretion, pathogen adherence to IECs, and mucin-3 (MUC3) and E-cadherin gene expression were assayed by TransAM assay, enzyme-linked immunosorbent assay (ELISA), fluorescence, and real-time reverse transcriptase–polymerase chain reaction (RT-PCR), respectively. IL-10 and tumour necrosis factor (TNF)-? secretion by bacteria-treated peripheral blood-derived DCs were measured using ELISA. S. typhimurium increased expression of 36 of the 847 immune-related genes assayed, including NF-?B and IL-8. The commensal bacteria did not alter expression levels of any of the 847 genes. However, B. infantis and L. salivarius attenuated both IL-8 secretion at baseline and S. typhimurium-induced pro-inflammatory responses. B. infantis also limited flagellin-induced IL-8 protein secretion. The commensal bacteria did not increase MUC3 or E-cadherin expression, or interfere with pathogen binding to HT-29 cells, but they did stimulate IL-10 and TNF-? secretion by DCs. The data demonstrate that, although the intestinal epithelium is immunologically quiescent when it encounters B. infantis or L. salivarius, these commensal bacteria exert immunomodulatory effects on intestinal immune cells that mediate host responses to flagellin and enteric pathogens.

O'Hara, Ann M; O'Regan, Padraig; Fanning, Aine; O'Mahony, Caitlin; MacSharry, John; Lyons, Anne; Bienenstock, John; O'Mahony, Liam; Shanahan, Fergus

2006-01-01

340

Regulation of villin by wnt5a/ror2 signaling in human intestinal cells.  

PubMed

Regulation of expression of the intestinal epithelial actin-binding protein, villin, is poorly understood. The aim of this study was to determine whether Wnt5a stimulates Ror2 in intestinal epithelia caused transient increases in phospho-ERK1/2 (pERK1/2) and subsequently increased expression of villin transcript and protein. To demonstrate Wnt5a-Ror2 regulation of villin expression, we overexpressed wild-type, truncated, or mutant Ror2 constructs in HT29 adenocarcinoma cells and non-transformed fetally derived human intestinal epithelial cells, added conditioned media containing Wnt5a and measured changes in ERK1/2 phosphorylation, villin amplicons, and protein expression by RT-PCR and Western blot techniques. Wnt5a addition caused a transient increase in pERK1/2, which was maximal at 10?min but extinguished by 30?min. Transient transfection with a siRNA duplex against Ror2 diminished Ror2 amplicons and protein and reduced the extent of pERK1/2 activation. Structure-function analysis revealed that the deletion of the cysteine-rich, kringle, or tyrosine kinase domain or substitution mutations of tyrosine residues in the intracellular Ser/Thr-1 region of Ror2 prevented the Wnt5a stimulation of pERK1/2. Deletion of the intracellular proline and serine/threonine-rich regions of Ror2 had no effect on Wnt5a stimulation of pERK1/2. The increase in villin expression was blocked by pharmacological inhibition of MEK-1 and casein kinase 1, but not by PKC and p38 inhibitors. Neither Wnt3a nor epidermal growth factor addition caused increases in villin protein. Our findings suggest that Wnt5a/Ror2 signaling can regulate villin expression in the intestine. PMID:21949508

Cheung, Rebecca; Kelly, Jacqueline; Macleod, R John

2011-01-01

341

Exogenous HIV-1 Nef Upsets the IFN-?-Induced Impairment of Human Intestinal Epithelial Integrity  

PubMed Central

Background The mucosal tissues play a central role in the transmission of HIV-1 infection as well as in the pathogenesis of AIDS. Despite several clinical studies reported intestinal dysfunction during HIV infection, the mechanisms underlying HIV-induced impairments of mucosal epithelial barrier are still unclear. It has been postulated that HIV-1 alters enterocytic function and HIV-1 proteins have been detected in several cell types of the intestinal mucosa. In the present study, we analyzed the effect of the accessory HIV-1 Nef protein on human epithelial cell line. Methodology/Principal Findings We used unstimulated or IFN-?-stimulated Caco-2 cells, as a model for homeostatic and inflamed gastrointestinal tracts, respectively. We investigated the effect of exogenous recombinant Nef on monolayer integrity analyzing its uptake, transepithelial electrical resistance, permeability to FITC-dextran and the expression of tight junction proteins. Moreover, we measured the induction of proinflammatory mediators. Exogenous Nef was taken up by Caco-2 cells, increased intestinal epithelial permeability and upset the IFN-?-induced reduction of transepitelial resistance, interfering with tight junction protein expression. Moreover, Nef inhibited IFN-?-induced apoptosis and up-regulated TNF-?, IL-6 and MIP-3? production by Caco-2 cells while down-regulated IL-10 production. The simultaneous exposure of Caco-2 cells to Nef and IFN-? did not affect cytokine secretion respect to untreated cells. Finally, we found that Nef counteracted the IFN-? induced arachidonic acid cascade. Conclusion/Significance Our findings suggest that exogenous Nef, perturbing the IFN-?-induced impairment of intestinal epithelial cells, could prolong cell survival, thus allowing for accumulation of viral particles. Our results may improve the understanding of AIDS pathogenesis, supporting the discovery of new therapeutic interventions.

Quaranta, Maria Giovanna; Vincentini, Olimpia; Felli, Cristina; Spadaro, Francesca; Silano, Marco; Moricoli, Diego; Giordani, Luciana; Viora, Marina

2011-01-01

342

Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-? activation  

PubMed Central

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [14C]oxalate uptake in the presence of an outward Cl? gradient as an assay of Cl?/oxalate exchange activity, ?50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-? knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y2 receptor, PLC, and PKC-?. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y2 receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y2 purinergic receptor, PLC, and PKC-?.

Amin, Ruhul; Sharma, Sapna; Ratakonda, Sireesha

2013-01-01

343

Initiation of an Inflammatory Response in Resident Intestinal Lamina Propria Cells -Use of a Human Organ Culture Model  

PubMed Central

Resident human lamina propria immune cells serve as powerful effectors in host defense. Molecular events associated with the initiation of an intestinal inflammatory response in these cells are largely unknown. Here, we aimed to characterize phenotypic and functional changes induced in these cells at the onset of intestinal inflammation using a human intestinal organ culture model. In this model, healthy human colonic mucosa was depleted of epithelial cells by EDTA treatment. Following loss of the epithelial layer, expression of the inflammatory mediators IL1B, IL6, IL8, IL23A, TNFA, CXCL2, and the surface receptors CD14, TLR2, CD86, CD54 was rapidly induced in resident lamina propria cells in situ as determined by qRT-PCR and immunohistology. Gene microarray analysis of lamina propria cells obtained by laser-capture microdissection provided an overview of global changes in gene expression occurring during the initiation of an intestinal inflammatory response in these cells. Bioinformatic analysis gave insight into signalling pathways mediating this inflammatory response. Furthermore, comparison with published microarray datasets of inflamed mucosa in vivo (ulcerative colitis) revealed a significant overlap of differentially regulated genes underlining the in vivo relevance of the organ culture model. Furthermore, genes never been previously associated with intestinal inflammation were identified using this model. The organ culture model characterized may be useful to study molecular mechanisms underlying the initiation of an intestinal inflammatory response in normal mucosa as well as potential alterations of this response in inflammatory bowel disease.

Schroder-Braunstein, Jutta; Gras, Judith; Brors, Benedikt; Schwarz, Sonja; Szikszai, Timea; Lasitschka, Felix; Wabnitz, Guido; Heidtmann, Antje; Lee, Young-Seon; Schiessling, Serin; Leowardi, Christine; Al-Saeedi, Mohammed; Ulrich, Alexis; Engelke, Antonia; Winter, Johannes; Samstag, Yvonne; Giese, Thomas; Meuer, Stefan

2014-01-01

344

Characterization and Ecology of Carboxymethylcellulase-Producing Anaerobic Bacterial Communities Associated with the Intestinal Tract of the Pinfish, Lagodon rhomboides  

PubMed Central

Carboxymethylcellulase (CMCase)-producing obligate anaerobes were isolated from the intestinal tract contents but not the feeding habitat of seagrass-consuming pinfish. Taxonomic characterization of these CMCase-producing strains revealed four taxonomic clusters; three were clostridial and one was of unknown taxonomic affinity. Our results demonstrated that the CMCase-producing obligate anaerobe community from pinfish differed from functionally similar microbial communities in terrestrial herbivores.

Stellwag, E. J.; Smith, T. D.; Luczkovich, J. J.

1995-01-01

345

Isolation of a human intestinal bacterium that transforms mangiferin to norathyriol and inducibility of the enzyme that cleaves a C-glucosyl bond.  

PubMed

The C-glucosyl bond of C-glucosides generally tolerates acid and enzymatic hydrolysis. Many C-glucosides are cleaved by human intestinal bacteria. We isolated the specific bacterium involved in the metabolism of mangiferin (2-beta-D-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone), C-glucosyl xanthone, from a mixture of human fecal bacteria. The anaerobic Bacteroides species named MANG, transformed mangiferin to the aglycone, norathyriol, suggesting cleavage of a C-glucosyl bond. However, B. sp. MANG cleaved C-glucosyl in a dose- and time-dependent manner only when cultivated in the presence of mangiferin. Cleavage was abolished by inhibitors of RNA and protein syntheses, such as rifampicin and chloramphenicol, respectively, indicating that the enzyme that cleaves C-glucosyl is induced by mangiferin. In contrast, mangiferin did not affect bacterial alpha- and beta-glucosidase activities under any conditions. The C-glucosyl-cleavage in cell-free extracts was not altered by potent glucosidase inhibitors such as 1-deoxynojirimycin and gluconolactone. Therefore, the C-glucosyl-cleaving enzyme substantially differs from known glucosidases that cleave O-glucosides. This is the first description of a specific intestinal bacterium that is involved in the metabolism of mangiferin and which produces a novel and inducible C-glucosyl-cleaving enzyme. PMID:16141538

Sanugul, Kanjana; Akao, Teruaki; Li, Yan; Kakiuchi, Nobuko; Nakamura, Norio; Hattori, Masao

2005-09-01

346

Intestinal parasite co-infection among pulmonary tuberculosis cases without human immunodeficiency virus infection in a rural county in China.  

PubMed

Epidemiologic studies of co-infection with tuberculosis (TB) and intestinal parasites in humans have not been extensively investigated in China. A cross-section study was conducted in a rural county of Henan Province, China. Pulmonary TB (PTB) case-patients receiving treatment for infection with Mycobacterium tuberculosis and healthy controls matched for geographic area, age, and sex were surveyed by using questionnaires. Fecal and blood specimens were collected for detection of intestinal parasites, routine blood examination, and infection with human immunodeficiency virus. The chi-square test was used for univariate analysis and multivariate logistic regression models were used to adjust for potential confounding factors. A total of 369 persons with PTB and 366 healthy controls were included; all participants were negative for human immunodeficiency virus. The overall prevalence of intestinal parasites in persons with PTB was 14.9%, including intestinal protozoa (7.9%) and helminthes (7.6%). The infection spectrum of intestinal parasites was Entamoeba spp. (1.4%), Blastocystis hominis (6.2%), Trichomonas hominis (0.3%), Clonorchis sinensis (0.3%), Ascaris lumbricoides (0.5%), Trichuris trichiura (2.2%), and hookworm (4.6%). The prevalence of intestinal parasites showed no significant difference between persons with PTB and healthy controls after adjusting for potential confounding factors. There was no factor that affected infection rates for intestinal parasites between the two groups. Infection with intestinal parasites of persons with PTB was associated with female sex (adjusted odds ratio [AOR] = 2.05, 95% confidence interval [CI] = 1.01-4.17), body mass index ? 19 (AOR = 3.02, 95% CI = 1.47-6.20), and anemia (AOR = 2.43, 95% CI = 1.17-5.03). Infection of healthy controls was only associated with an annual labor time in farmlands > 2 months (AOR = 4.50, 95% CI = 2.03-10.00). In addition, there was no significant trend between rates of infection with intestinal parasites and duration of receiving treatment for infection with M. tuberculosis in persons with PTB. The prevalence of intestinal parasites was not higher in persons with PTB, and there was no evidence that PTB increased susceptibility to intestinal parasites in this study. However, for patients with PTB, women and patients with comorbidities were more likely to be infected with intestinal parasites. PMID:24166044

Li, Xin-Xu; Chen, Jia-Xu; Wang, Li-Xia; Tian, Li-Guang; Zhang, Yu-Ping; Dong, Shuang-Pin; Hu, Xue-Guang; Liu, Jian; Wang, Feng-Feng; Wang, Yue; Yin, Xiao-Mei; He, Li-Jun; Yan, Qiu-Ye; Zhang, Hong-Wei; Xu, Bian-Li; Zhou, Xiao-Nong

2014-01-01

347

RGD-Dependent Epithelial Cell-Matrix Interactions in the Human Intestinal Crypt  

PubMed Central

Interactions between the extracellular matrix (ECM) and integrin receptors trigger structural and functional bonds between the cell microenvironment and the cytoskeleton. Such connections are essential for adhesion structure integrity and are key players in regulating transduction of specific intracellular signals, which in turn regulate the organization of the cell microenvironment and, consequently, cell function. The RGD peptide-dependent integrins represent a key subgroup of ECM receptors involved in the maintenance of epithelial homeostasis. Here we review recent findings on RGD-dependent ECM-integrin interactions and their roles in human intestinal epithelial crypt cells.

Benoit, Yannick D.; Groulx, Jean-Francois; Gagne, David; Beaulieu, Jean-Francois

2012-01-01

348

Triacylglycerol Biosynthesis in Human Small Intestinal Mucosa. Acyl-CoA: Monoglyceride Acyltransferase  

Microsoft Academic Search

Acyl-CoA: monoglyceride acyltransferase (MGAT; EC 2.3.1.22) has been studied in human small intestinal mucosa by means of a spectrophotometric method based on the detection of liberated CoA employing 5,5´-dithiobis-(2-nitrobenzoic acid). With optimal assay conditions available the pH optimum was spread between 7.0 and 7.7 with a maximum at a pH of 7.4. Dependent on its concentration one of the substrates,

Hartmut Bierbach

1983-01-01

349

Structural characterization of BVU_3255, a methyltransferase from human intestine antibiotic resistant pathogen Bacteroides vulgatus.  

PubMed

Methylation is important for various cellular activities. To date, there is no report of any methyltransferase structure from the human intestine antibiotic resistant pathogen Bacteroides vulgatus. The protein BVU_3255 from B. vulgatus ATCC 8482 belongs to a SAM-dependent methyltransferase. Here, we report the crystal structure of apo BVU_3255, and its complexes with SAM and SAH, which revealed a typical class I Rossmann Fold Methyltransferase. Isothermal titration calorimetric studies showed that both SAM and SAH bind with equal affinity. The structural and sequence analysis suggested that BVU_3255 is a small molecule methyltransferase and involved in methylating the intermediates in ubiquinone biosynthesis pathway. PMID:21872662

Kumar, Veerendra; Sivaraman, J

2011-12-01

350

Recellularization of Acellular Human Small Intestine Using Bone Marrow Stem Cells  

PubMed Central

We aimed to produce an acellular human tissue scaffold with a view to test the possibility of recellularization with bone marrow stem cells to produce a tissue-engineered small intestine (TESI). Human small-bowel specimens (n = 5) were obtained from cadaveric organ donors and treated sequentially with 6% dimethyl sulfoxide in hypotonic buffer, 1% Triton X-100, and DNase. Each small intestine (SI) piece (6 cm) was recellularized with EPCAM+ and CD133+ allogeneic bone marrow stem cells. Histological and molecular analysis demonstrated that after decellularization, all cellular components and nuclear material were removed. Our analysis also showed that the decellularized human SI tissue retained its histoarchitecture with intact villi and major structural proteins. Protein films of common extracellular matrix constituents (collagen I, laminin, and fibronectin) were found in abundance. Furthermore, several residual angiogenic factors were found in the decellularized SI. Following recellularization, we found viable mucin-positive goblet cells, CK18+ epithelial cells in villi adjacent to a muscularis mucosa with ?-actin+ smooth muscle cells, and a high repopulation of blood vessels with CD31+ endothelial cells. Our results show that in the future, such a TESI would be ideal for clinical purposes, because it can be derived from the recipient's own immunocompatible bone marrow cells, thus avoiding the use of immunosuppression.

Patil, Pradeep B.; Chougule, Priti B.; Kumar, Vijay K.; Almstrom, Stefan; Backdahl, Henrik; Banerjee, Debashish; Herlenius, Gustaf; Olausson, Michael

2013-01-01

351

Transepithelial transport of ambroxol hydrochloride across human intestinal Caco-2 cell monolayers.  

PubMed

This study aimed i) to characterize the transepithelial transport of the mucolytic agent ambroxol hydrochloride across the intestinal barrier, ii) to classify the ambroxol according to Biopharmaceutics Classification System (BCS) and iii) to predict ambroxol absorption in humans. Transport of ambroxol (100, 300 and 1000 micromol/l) was studied in a human colon carcinoma cell line Caco-2 in apical to basolateral and basolateral to apical direction, under iso-pH 7.4 and pH-gradient (6 vs. 7.4) conditions. The relative contribution of the paracellular route was estimated using Ca2+-free transport medium. Ambroxol samples from receiver compartments were analysed by HPLC with UV detection (242 nm). Results showed that ambroxol transport is linear with time, pH-dependent and direction-independent, displays non-saturable (first-order) kinetics. Thus, the transport seems to be transcellular mediated by passive diffusion. Estimated high solubility and high permeability (P(app) = 45 x 10(-6) cm/s) of ambroxol rank it among well absorbed compounds and class I of BCS. It can be expected that the oral dose fraction of ambroxol absorbed in human intestine is high. PMID:20037197

Stetinová, Vera; Smetanová, Libuse; Kholová, Dagmar; Svoboda, Zbynek; Kvetina, Jaroslav

2009-09-01

352

Nuclear Targeting of a Bacterial Integrase That Mediates Site-Specific Recombination between Bacterial and Human Target Sequences?  

PubMed Central

TrwC is a bacterial protein involved in conjugative transfer of plasmid R388. It is transferred together with the DNA strand into the recipient bacterial cell, where it can integrate the conjugatively transferred DNA strand into its target sequence present in the recipient cell. Considering that bacterial conjugation can occur between bacteria and eukaryotic cells, this protein has great biotechnological potential as a site-specific integrase. We have searched for possible TrwC target sequences in the human genome. Recombination assays showed that TrwC efficiently catalyzes recombination between its natural target sequence and a discrete number of sequences, located in noncoding sites of the human genome, which resemble this target. We have determined the cellular localization of TrwC and derivatives in human cells by immunofluorescence and also by an indirect yeast-based assay to detect both nuclear import and export signals. The results indicate that the recombinase domain of TrwC (N600) has nuclear localization, but full-length TrwC locates in the cytoplasm, apparently due to the presence of a nuclear export signal in its C-terminal domain. The recombinase domain of TrwC can be transported to recipient cells by conjugation in the presence of the helicase domain of TrwC, but with very low efficiency. We mutagenized the trwC gene and selected for mutants with nuclear localization. We obtained one such mutant with a point A904T mutation and an extra peptide at its C terminus, which maintained its functionality in conjugation and recombination. This TrwC mutant could be useful for future TrwC-mediated site-specific integration assays in mammalian cells.

Agundez, Leticia; Machon, Cristina; Cesar, Carolina Elvira; Rosa-Garrido, Manuel; Delgado, M. Dolores; Llosa, Matxalen

2011-01-01

353

More than 9,000,000 Unique Genes in Human Gut Bacterial Community: Estimating Gene Numbers Inside a Human Body  

Microsoft Academic Search

BackgroundEstimating the number of genes in human genome has been long an important problem in computational biology. With the new conception of considering human as a super-organism, it is also interesting to estimate the number of genes in this human super-organism.Principal FindingsWe presented our estimation of gene numbers in the human gut bacterial community, the largest microbial community inside the

Xing Yang; Lu Xie; Yixue Li; Chaochun Wei; Stefan Bereswill

2009-01-01

354

Role of intestinal epithelial cells in the host secretory response to infection by invasive bacteria. Bacterial entry induces epithelial prostaglandin h synthase-2 expression and prostaglandin E2 and F2alpha production.  

PubMed Central

Increased intestinal fluid secretion is a protective host response after enteric infection with invasive bacteria that is initiated within hours after infection, and is mediated by prostaglandin H synthase (PGHS) products in animal models of infection. Intestinal epithelial cells are the first host cells to become infected with invasive bacteria, which enter and pass through these cells to initiate mucosal, and ultimately systemic, infection. The present studies characterized the role of intestinal epithelial cells in the host secretory response after infection with invasive bacteria. Infection of cultured human intestinal epithelial cell lines with invasive bacteria, but not noninvasive bacteria, is shown to induce the expression of one of the rate-limiting enzymes for prostaglandin formation, PGHS-2, and the production of PGE2 and PGF2alpha. Furthermore, increased PGHS-2 expression was observed in intestinal epithelial cells in vivo after infection with invasive bacteria, using a human intestinal xenograft model in SCID mice. In support of the physiologic importance of epithelial PGHS-2 expression, supernatants from bacteria-infected intestinal epithelial cells were shown to increase chloride secretion in an in vitro model using polarized epithelial cells, and this activity was accounted for by PGE2. These studies define a novel autocrine/paracrine function of mediators produced by intestinal epithelial cells in the rapid induction of increased fluid secretion in response to intestinal infection with invasive bacteria.

Eckmann, L; Stenson, W F; Savidge, T C; Lowe, D C; Barrett, K E; Fierer, J; Smith, J R; Kagnoff, M F

1997-01-01

355

Penetration of Human Intestinal Epithelial Cells by Salmonella: Molecular Cloning and Expression of Salmonella typhi Invasion Determinants in Escherichia coli  

Microsoft Academic Search

Salmonella typhi, the causative agent of typhoid fever, must invade the human gastrointestinal tract and multiply within the host to cause disease. We have cloned from S. typhi Ty2 a chromosomal region that confers upon Escherichia coli HB101 the ability to invade cultured human intestinal epithelial cells. Three invasion-positive recombinant cosmids were isolated and restriction endonuclease analyses of the inserts

Eric A. Elsinghorst; Louis S. Baron; Dennis J. Kopecko

1989-01-01

356

Modulation of stemness in a human normal intestinal epithelial crypt cell line by activation of the WNT signaling pathway.  

PubMed

The small intestine consists of two histological compartments composed of the crypts and the villi. The function of the adult small intestinal epithelium is mediated by four different types of mature cells: enterocytes, goblet, enteroendocrine and Paneth. Undifferentiated cells reside in the crypts and produce these four types of mature cells. The niche-related Wnt and Bmp signaling pathways have been suggested to be involved in the regulation and maintenance of the stem cell microenvironment. In our laboratory, we isolated the first normal human intestinal epithelial crypt (HIEC) cell model from the human fetal intestine and in this study we investigated the expression of a panel of intestinal stem cell markers in HIEC cells under normal culture parameters as well as under conditions that mimic the stem cell microenvironment. The results showed that short term stimulation of HIEC cells with R-spondin 1 and Wnt-3a±SB-216763, a glycogen synthase kinase 3? (GSK3?) inhibitor, induced ?-catenin/TCF activity and expression of the WNT target genes, cyclin D2 and LGR5. Treatment of HIEC cells with noggin, an antagonist of BMP signaling, abolished SMAD2/5/8 phosphorylation. Inducing a switch from inactive WNT/active BMP toward active WNT/inactive BMP pathways was sufficient to trigger a robust intestinal primordial stem-like cell signature with predominant LGR5, PHLDA1, PROM1, SMOC2 and OLFM4 expression. These findings demonstrate that even fully established cultures of intestinal cells can be prompted toward a CBC stem cell-like phenotype. This model should be useful for studying the regulation of human intestinal stem cell self-renewal and differentiation. PMID:24534551

Guezguez, Amel; Paré, Fréderic; Benoit, Yannick D; Basora, Nuria; Beaulieu, Jean-François

2014-04-01

357

Intestinal dendritic cells: their role in intestinal inflammation, manipulation by the gut microbiota and differences between mice and men.  

PubMed

The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance of the commensal microbiota and food antigens. Dendritic cells (DC) generate primary T-cell responses, and determine whether these responses are immunogenic or tolerogenic. The regulatory role of DC is of particular importance in the gut due to the high antigenic load. Intestinal DC act as sentinels, sampling potentially pathogenic antigens but also harmless antigens including the commensal microbiota. Following antigen acquisition, intestinal DC migrate to secondary lymphoid organs to activate naive T-cells. DC also imprint specific homing properties on T-cells that they stimulate; gut DC specifically induce gut-homing properties on T-cells upon activation, enabling T-cell migration back to intestinal sites. Data regarding properties on gut DC in humans is scarce, although evidence now supports the role of DC as important players in intestinal immunity in humans. Here, we review the role of intestinal DC in shaping mucosal immune responses and directing tissue-specific T-cell responses, with a special focus on the importance of distinguishing DC subsets from macrophages at intestinal sites. We compare and contrast human DC with their murine counterparts, and discuss the ability of the gut microbiota to shape intestinal DC function, and how this may be dysregulated in inflammatory bowel disease (IBD). Lastly, we describe recent advances in the study of probiotics on intestinal DC function, including the use of soluble secreted bacterial products. PMID:23352670

Mann, Elizabeth R; Landy, Jonathan D; Bernardo, David; Peake, Simon T C; Hart, Ailsa L; Al-Hassi, Hafid Omar; Knight, Stella C

2013-02-01

358

Human Pathogens Abundant in the Bacterial Metagenome of Cigarettes  

PubMed Central

Background Many studies have evaluated chemical, heavy metal, and other abiotic substances present in cigarettes and their roles in the development of lung cancer and other diseases, yet no studies have comprehensively evaluated bacterial diversity of cigarettes and the possible impacts of these microbes on respiratory illnesses in smokers and exposed nonsmokers. Objectives The goal of this study was to explore the bacterial metagenomes of commercially available cigarettes. Methods A 16S rRNA-based taxonomic microarray and cloning and sequencing were used to evaluate total bacterial diversity of four brands of cigarettes. Normalized microarray data were compared using principal component analysis and hierarchical cluster analysis to evaluate potential differences in microbial diversity across cigarette brands. Results Fifteen different classes of bacteria and a broad range of potentially pathogenic organisms were detected in all cigarette samples. Most notably, we detected Acinetobacter, Bacillus, Burkholderia, Clostridium, Klebsiella, Pseudomonas aeruginosa, and Serratia in ? 90% of all cigarette samples. Other pathogenic bacteria detected included Campylobacter, Enterococcus, Proteus, and Staphylococcus. No significant variability in bacterial diversity was observed across the four different cigarette brands. Conclusions Previous studies have shown that smoking is associated with colonization by pathogenic bacteria and an increased risk of lung infections. However, this is the first study to show that cigarettes themselves could be the direct source of exposure to a wide array of potentially pathogenic microbes among smokers and other people exposed to secondhand smoke. The overall public health implications of these findings are unclear at this time, and future studies are necessary to determine whether bacteria in cigarettes could play important roles in the development of both infectious and chronic respiratory diseases.

Sapkota, Amy R.; Berger, Sibel; Vogel, Timothy M.

2010-01-01

359

Expression and intracellular transport of microvillus membrane hydrolases in human intestinal epithelial cells  

PubMed Central

A panel of monoclonal antibodies was produced against purified microvillus membranes of human small intestinal enterocytes. By means of these probes three disaccharidases (sucrase-isomaltase, lactase- phlorizin hydrolase, and maltase-glucoamylase) and four peptidases (aminopeptidase N, dipeptidylpeptidase IV, angiotension I-converting enzyme, and p-aminobenzoic acid peptide hydrolase) were successfully identified as individual entities by SDS PAGE and localized in the microvillus border of the enterocytes by immunofluorescence microscopy. The antibodies were used to study the expression of small intestinal hydrolases in the colonic adenocarcinoma cell line Caco 2. This cell line was found to express sucrase-isomaltase, lactase-phlorizin hydrolase, aminopeptidase N, and dipeptidylpeptidase IV, but not the other three enzymes. Pulse-chase studies with [35S]methionine and analysis by subunit-specific monoclonal antibodies revealed that sucrase-isomaltase was synthesized and persisted as a single-chain protein comprising both subunits. Similarly, lactase-phlorizin hydrolase was synthesized as a large precursor about twice the size of the lactase subunits found in the human intestine. Aminopeptidase N and dipeptidylpeptidase IV, known to be dimeric enzymes in most mammals, were synthesized as monomers. Transport from the rough endoplasmic reticulum to the trans-Golgi apparatus was considerably faster for the peptidases than for the disaccharidases, as probed by endoglycosidase H sensitivity. These results suggest that the major disaccharidases share a common biosynthetic mechanism that differs from that for peptidases. Furthermore, the data indicate that the transport of microvillus membrane proteins to and through the Golgi apparatus is a selective process that may be mediated by transport receptors.

1985-01-01

360

Studies on long chain fatty acid:CoA ligase from human small intestine.  

PubMed Central

Long chain fatty acid:CoA ligase (EC 6.2.1.3.) was examined in human small intestinal mucosa using the hydroxamate-trapping method. With optimal assay requirements using palmitate as substrate a significant difference of specific activities could be detected in the total homogenate from duodenum, 40.9 +/- 11.6 nmol/min per mg protein versus upper jejunum, 51.9 +/- 13.7 (P less than 0.05). The enzyme activity of the microsomal fraction of upper jejunum was 101.8 +/- 44 nmol/min per mg protein. ATP, CoA, and Mg2+ were essential constituents of the reaction. A broad pH-optimum was observed between 6.75 and 7.75 with a maximum at a pH of 7.25. Whereas palmitate in the presence of albumin revealed a wide range of optimal concentration in supporting maximal enzyme activity, oleate was found to strongly inhibit the reaction. Where substrate specificity with both the total homogenate and the microsomal fraction was concerned, maximal reaction rates were obtained with palmitate for the long chain saturated fatty acids C12:0' C14:0' C16:0' and C18:0' and with oleate for the long chain unsaturated fatty acids C18:1 C18:2' and C18:3' respectively. The highest specific activity of the enzyme was localised in the microsomal fraction. The kinetic data and properties of the long chain fatty acid: CoA ligase from human intestine are discussed with respect to the intestinal enzyme from other species.

Bierbach, H

1980-01-01

361

T cells of the human intestinal lamina propria are high producers of interleukin-10  

PubMed Central

Background and aim—Some of the recently observed functional features characteristic of immunocompetent cells residing in the human intestinal lamina propria could be mediated by interleukin- 10 (IL-10). To investigate the role of IL-10 in the human intestinal mucosa, the regulation of IL-10 production by lamina propria T lymphocytes (LPL-T) was determined and compared with that of peripheral blood T lymphocytes (PBL-T). ?Methods—Following activation by using different stimuli, IL-10 release by LPL-T and PBL-T into the supernatant was measured by enzyme linked immunosorbent assay (ELISA). In parallel, cell growth was determined by [3H]-thymidine incorporation. ?Results—Neither LPL-T nor PBL-T release IL-10 constitutively. Triggering through CD2 or the T cell receptor (TCR)/CD3 complex in the presence of autologous monocytes induces significantly greater IL-10 secretion by LPL-T than by PBL-T. Engagement of the CD45 receptor enhances IL-10 release and proliferation of CD2 triggered CD45RO+ PBL-T. In contrast, it reduces CD2 induced IL-10 production by LPL-T without altering cell growth significantly. ?Conclusions—Activated LPL-T release relatively high amounts of IL-10. Enhanced IL-10 production by activated LPL-T, in comparison with activated PBL-T, is not only related to the presence of a higher proportion of CD45RO+ T cells in the intestinal lamina propria, but is also caused by increased sensitivity of LPL-T to CD2 co-stimulation. The differential responsiveness of LPL-T, compared with PBL-T, to CD45 engagement demonstrates that CD45 could be involved in the altered CD2 reactivity of LPL-T. ?? Keywords: CD2; CD45; interleukin 10; lamina propria; T cell subsets; T lymphocytes

Braunstein, J; Qiao, L; Autschbach, F; Schurmann, G; Meuer, S

1997-01-01

362

Description of urolithin production capacity from ellagic acid of two human intestinal Gordonibacter species.  

PubMed

Ellagitannin and ellagic acid metabolism to urolithins in the gut shows a large human interindividual variability and this has been associated with differences in the colon microbiota. In the present study we describe the isolation of one urolithin-producing strain from the human faeces of a healthy volunteer and the ellagic acid transformation to different urolithin metabolites by two species of intestinal bacteria. The isolate belongs to a new species described as Gordonibacter urolithinfaciens, sp. nov. The type strain of the Gordonibacter genus, Gordonibacter pamelaeae DSM 19378(T), was also demonstrated to produce urolithins. Both human intestinal bacteria grew similarly in the presence and absence of ellagic acid at 30 ?M concentration. Ellagic acid catabolism and urolithin formation occurred during the stationary phase of the growth of the bacteria under anaerobic conditions. The HPLC-MS analyses showed the sequential production of pentahydroxy-urolithin (urolithin M-5), tetrahydroxy-urolithin (urolithin M-6) and trihydroxy-urolithin (urolithin C), while dihydroxy-urolithins (urolithin A and isourolithin A), and monohydroxy-urolithin (urolithin B) were not produced in pure cultures. Consequently, either other bacteria from the gut or the physiological conditions found in vivo are necessary for completing metabolism until the final urolithins (dihydroxy and monohydroxy urolithins) are produced. This is the first time that the urolithin production capacity of pure strains has been demonstrated. The identification of the urolithin-producing bacteria is a relevant outcome as urolithin implication in health (cardiovascular protection, anti-inflammatory and anticarcinogenic properties) has been supported by different bioassays and urolithins can be used in the development of functional foods and nutraceuticals. This study represents an initial work that opens interesting possibilities of describing enzymatic activities involved in urolithin production that can help in understanding both the human interindividual differences in polyphenol metabolism, the microbial pathways involved, and the role of polyphenols in human health. The presence of urolithin producing bacteria can indirectly affect the health benefits of ellagitannin consumption. PMID:24909569

Selma, María V; Beltrán, David; García-Villalba, Rocío; Espín, Juan C; Tomás-Barberán, Francisco A

2014-07-23

363

The High Affinity IgE Receptor Fc?RI Is Expressed by Human Intestinal Epithelial Cells  

PubMed Central

Background IgE antibodies play a paramount role in the pathogenesis of various intestinal disorders. To gain insights in IgE-mediated pathophysiology of the gut, we investigated the expression of the high affinity IgE receptor Fc?RI in human intestinal epithelium. Methodology/Principal Findings Fc?RI ?-chain, as detected by immunohistochemistry, was positive in epithelial cells for eight of eleven (8/11) specimens from colon cancer patients and 5/11 patients with inflammation of the enteric mucosa. The Fc?RI? positive epithelial cells co-expressed Fc?RI?, whereas with one exception, none of the samples was positive for the ?-chain in the epithelial layer. The functionality of Fc?RI was confirmed in situ by human IgE binding. In experiments with human intestinal tumor cell lines, subconfluent Caco-2/TC7 and HCT-8 cells were found to express the ?- and ?-chains of Fc?RI and to bind IgE, whereas confluent cells were negative for ?-chains. Conclusions/Significance Our data provide the first evidence that the components of a functional Fc?RI are in vitro expressed by the human intestinal epithelial cells depending on differentiation and, more importantly, in situ in epithelia of patients with colon cancer or gastrointestinal inflammations. Thus, a contribution of Fc?RI either to immunosurveillance or pathophysiology of the intestinal epithelium is suggested.

Starkl, Philipp; Bevins, Charles L.; Scheiner, Otto; Boltz-Nitulescu, George; Wrba, Fritz; Jensen-Jarolim, Erika

2010-01-01

364

Activation of the innate immune system and alcoholic liver disease: effects of ethanol per se or enhanced intestinal translocation of bacterial toxins induced by ethanol?  

PubMed

It is generally accepted that activation of the innate immune system and increased release of pro-inflammatory cytokines and other mediators plays an important role in the development of alcoholic liver disease (ALD). The mechanisms involved in the ethanol-induced activation of monocytes/macrophages (including Kupffer cells) are however, still a matter of debate. The brief review will summarize the published data from the literature on the two main pathomechanisms discussed until now: I) Gut-derived bacterial toxins, specially endotoxin; and II) metabolic changes induced by alcohol oxidation (independent of mechanism I). For pathomechanism I, clear evidence has been published from numerous groups: Alcohol induces mucosal injury in the upper gastrointestinal tract and leads to marked increase in the permeability of the gut mucosa to macromolecules such as endotoxin. The resulting endotoxemia then leads to activation of Kupffer cells and other macrophages. The increased release of pro-inflammatory mediators (e.g., TNF-alpha, Il-1, reacting oxygen species) and infiltration of other inflammatory cells (e.g., neutrophils) finally causes liver damage. Regarding the second pathomechanism it has repeatedly been argued that the metabolic alterations which are induced by chronic administration of ethanol to rats or mice might increase the sensitivity of monocytes/macrophages to secrete TNF-alpha and other pro-inflammatory mediators thereby increasing the susceptibility to ethanol-induced liver injury. However, in all feeding experiments the effect of ethanol on intestinal permeability and enhanced translocation of bacterial toxins (endotoxin) is likely to occur (or at least cannot be excluded). The latter holds true also for experiments using isolated macrophages/Kupffer cells from ethanol fed animals. Therefore, to clarify whether or not alterations related to ethanol metabolism ("direct" effects of ethanol) contribute to the activation of the innate immune system studies using germ-free animals are needed to exclude the "indirect" effect of ethanol via gut-derived bacterial toxins. PMID:16344604

Bode, Christiane; Bode, J Christian

2005-11-01

365

Forest Fragmentation as Cause of Bacterial Transmission among Nonhuman Primates, Humans, and Livestock, Uganda  

PubMed Central

We conducted a prospective study of bacterial transmission among humans, nonhuman primates (primates hereafter), and livestock in western Uganda. Humans living near forest fragments harbored Escherichia coli bacteria that were ?75% more similar to bacteria from primates in those fragments than to bacteria from primates in nearby undisturbed forests. Genetic similarity between human/livestock and primate bacteria increased ?3-fold as anthropogenic disturbance within forest fragments increased from moderate to high. Bacteria harbored by humans and livestock were approximately twice as similar to those of red-tailed guenons, which habitually enter human settlements to raid crops, than to bacteria of other primate species. Tending livestock, experiencing gastrointestinal symptoms, and residing near a disturbed forest fragment increased genetic similarity between a participant’s bacteria and those of nearby primates. Forest fragmentation, anthropogenic disturbance within fragments, primate ecology, and human behavior all influence bidirectional, interspecific bacterial transmission. Targeted interventions on any of these levels should reduce disease transmission and emergence.

Gillespie, Thomas R.; Rwego, Innocent B.; Estoff, Elizabeth L.; Chapman, Colin A.

2008-01-01

366

Transport and function of syntaxin 3 in human epithelial intestinal cells.  

PubMed

To follow the transport of human syntaxin (Syn) 3 to the apical surface of intestinal cells, we produced and expressed in Caco-2 cells a chimera made of the entire Syn3 coding sequence and the extracellular domain of the human transferrin receptor (TfR). This chimera (Syn3TfR) was localized to the apical membrane and was transported along the direct apical pathway, suggesting that this is also the case for endogenous Syn3. To test the potential role of Syn3 in apical transport, we overexpressed it in Caco-2 cells and measured the efficiency of apical and basolateral delivery of several endogenous markers. We observed a strong inhibition of apical delivery of sucrase-isomaltase (SI), an apical transmembrane protein, and of alpha-glucosidase, an apically secreted protein. No effect was observed on the basolateral delivery of Ag525, a basolateral antigen, strongly suggesting that Syn3 is necessary for efficient delivery of proteins to the apical surface of intestinal cells. PMID:11003604

Breuza, L; Fransen, J; Le Bivic, A

2000-10-01

367

Engineered nanoparticles induced brush border disruption in a human model of the intestinal epithelium.  

PubMed

Nanoparticles hold great promise in cell biology and medicine due to the inherent physico-chemical properties when these materials are synthesized on the nanoscale. Moreover, their small size, and the ability to functionalize the outer nanoparticle surface makes them an ideal vector suited to traverse a number of physical barriers in the human body. While nanoparticles hold great promise for applications in cell biology and medicine, their downfall is the toxicity that accompanies exposure to biological systems. This chapter focuses on exposure via the oral route since nanomaterials are being engineered to act as carriers for drugs, contrast agents for specialized imaging techniques, as well as ingested pigments approved by regulatory agencies for human food products. After these nanomaterials are ingested they have the potential to interact with a number of biologically significant tissues, one of which is the epithelium of the small intestine. Within the small intestine exists enterocytes whose principal function is nutrient absorption. The absorptive process is aided by microvilli that act to increase the surface area of the epithelium. Dense arrays of microvilli, referred to as the brush border, have recently been shown to undergo disruption as a consequence of exposure to nanomaterials. This chapter aims to set the stage for detailed mechanistic studies at the cell biology level concerning this newly emerging nanotoxicity research paradigm, as the underlying structural characterization responsible for the existence of microvilli have been elucidated. PMID:24683027

Faust, James J; Masserano, Benjamin M; Mielke, Adam H; Abraham, Anup; Capco, David G

2014-01-01

368

Sugars Increase Non-Heme Iron Bioavailability in Human Epithelial Intestinal and Liver Cells  

PubMed Central

Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55) increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.

Christides, Tatiana; Sharp, Paul

2013-01-01

369

Characterization of an Escherichia coli O157:H7 O-Antigen Deletion Mutant and Effect of the Deletion on Bacterial Persistence in the Mouse Intestine and Colonization at the Bovine Terminal Rectal Mucosa?  

PubMed Central

Escherichia coli O157:H7 causes hemorrhagic colitis and the life-threatening hemolytic-uremic syndrome in humans and transiently colonizes healthy cattle at the terminal rectal mucosa. To investigate the role of the O antigen in persistence and colonization in the animal host, we generated an E. coli O157:H7 mutant defective in the synthesis of the lipopolysaccharide side chain (O antigen) by deletion of a putative perosamine synthetase gene (per) in the rfb cluster. The lack of O antigen was confirmed by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and anti-O157 antibody. The growth rate and cell membrane permeability of the ?per mutant were similar to the growth rate and cell membrane permeability of the wild type. Changes in membrane and secreted proteins were observed, but the expression of intimin, EspA, and EspB, implicated in bacterial intestinal colonization, was not altered, as determined by immunoblotting and reverse transcription-PCR. Similar to other O-antigen deletion mutants, the ?per mutant was pleiotropic for autoaggregation and motility (it was FliC negative as determined by immunoblotting and flagellum negative as determined by electron microscopy). The abilities of the mutant and the wild type to persist in the murine intestine and to colonize the bovine terminal rectal mucosa were compared. Mice fed the ?per mutant shed lower numbers of bacteria (P < 0.05) over a shorter time than mice fed the wild-type or complemented strain. After rectal application in steers, lower numbers of the ?per mutant than of the wild type colonized the rectoanal junction mucosa, and the duration of the colonization was shorter (P < 0.05). Our previous work showed that flagella do not influence E. coli O157:H7 colonization at the bovine terminal rectal mucosa, so the current findings suggest that the O antigen contributes to efficient bovine colonization.

Sheng, Haiqing; Lim, Ji Youn; Watkins, Maryann K.; Minnich, Scott A.; Hovde, Carolyn J.

2008-01-01

370

Humanized mouse model to study bacterial infections targeting the microvasculature.  

PubMed

Neisseria meningitidis causes a severe, frequently fatal sepsis when it enters the human blood stream. Infection leads to extensive damage of the blood vessels resulting in vascular leak, the development of purpuric rashes and eventual tissue necrosis. Studying the pathogenesis of this infection was previously limited by the human specificity of the bacteria, which makes in vivo models difficult. In this protocol, we describe a humanized model for this infection in which human skin, containing dermal microvessels, is grafted onto immunocompromised mice. These vessels anastomose with the mouse circulation while maintaining their human characteristics. Once introduced into this model, N. meningitidis adhere exclusively to the human vessels, resulting in extensive vascular damage, inflammation and in some cases the development of purpuric rash. This protocol describes the grafting, infection and evaluation steps of this model in the context of N. meningitidis infection. The technique may be applied to numerous human specific pathogens that infect the blood stream. PMID:24747976

Melican, Keira; Aubey, Flore; Duménil, Guillaume

2014-01-01

371

Morphine Induces Bacterial Translocation in Mice by Compromising Intestinal Barrier Function in a TLR-Dependent Manner  

PubMed Central

Opiates are among the most prescribed drugs for pain management. However, morphine use or abuse results in significant gut bacterial translocation and predisposes patients to serious infections with gut origin. The mechanism underlying this defect is still unknown. In this report, we investigated the mechanisms underlying compromised gut immune function and bacterial translocation following morphine treatment. We demonstrate significant bacterial translocation to mesenteric lymph node (MLN) and liver following morphine treatment in wild-type (WT) animals that was dramatically and significantly attenuated in Toll-like receptor (TLR2 and 4) knockout mice. We further observed significant disruption of tight junction protein organization only in the ileum but not in the colon of morphine treated WT animals. Inhibition of myosin light chain kinase (MLCK) blocked the effects of both morphine and TLR ligands, suggesting the role of MLCK in tight junction modulation by TLR. This study conclusively demonstrates that morphine induced gut epithelial barrier dysfunction and subsequent bacteria translocation are mediated by TLR signaling and thus TLRs can be exploited as potential therapeutic targets for alleviating infections and even sepsis in morphine-using or abusing populations.

Meng, Jingjing; Yu, Haidong; Ma, Jing; Wang, Jinghua; Banerjee, Santanu; Charboneau, Rick; Barke, Roderick A.; Roy, Sabita

2013-01-01

372

Tryptophan from human milk induces oxidative stress and upregulates the Nrf-2-mediated stress response in human intestinal cell lines.  

PubMed

Chemical screening of digested human milk protein using the oxygen radical absorbance capacity (ORAC(FL)) antioxidant assay confirmed the presence of a peptide fraction (PF23) with high antioxidant activity [5.53 mmol Trolox equivalents (TE)/g] that contained tryptophan as a main component. We evaluated the effects of both PF23 and tryptophan alone on the modulation of oxidative stress in cultured intestinal cells using a dichlorofluorescein diacetate probe. Despite the high ORAC(FL) value, PF23 enhanced (P < 0.05) 2, 2'-azobis (2-amidinopropane) dihydrochloride (peroxyl radical generator)-induced intracellular oxidation in the Caco-2 human adenocarcinoma cell line, suggesting prooxidant activity. Compared to selected peptide fractions with relatively lower ORAC(FL) values, PF23 induced oxidative stress more than all other peptide fractions tested (P < 0.05) and contained more tryptophan than the others (P < 0.05). Similar prooxidant activity was observed for tryptophan when it was added to culture medium for both the Caco-2 cells and FHs 74 Int primary fetal enterocytes, while also exhibiting a high ORAC(FL) value (9.69 mmol TE/g). The effect of tryptophan that involves activation of the Nrf-2 pathway and transcription of antioxidant enzymes was therefore investigated in FHs 74 Int cells. Exposure of infant intestinal cells to tryptophan resulted in Nrf-2 activation and an increase in the gene transcript level of glutathione peroxidase 2. We conclude that tryptophan-induced oxidative stress associated with tryptophan-containing milk peptides induces an adaptive response that involves the activation of the antioxidant responsive signaling pathway in intestinal cells. PMID:21677072

Elisia, Ingrid; Tsopmo, Apollinaire; Friel, James K; Diehl-Jones, William; Kitts, David D

2011-08-01

373

Ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry for determination of avicularin metabolites produced by a human intestinal bacterium.  

PubMed

Intestinal bacteria from human were screened to isolate the specific bacteria involved in the metabolism of avicularin. A Gram-positive anaerobic bacterium, strain 46, capable of metabolizing avicularin (quercetin-3-O-arabinoside) was isolated for the first time. Its 16S rRNA gene sequence showed 99% similarity with that of Bacillus. Then strain 46 was identified as a species of the genus Bacillus, and was named to be Bacillus sp. 46. Additionally, the metabolites were analyzed by ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) technique combined with Metabolynx™ software. The structure of these metabolites were proposed and confirmed by comparing the UPLC retention time and MS/MS spectrum with that of authentic standards. Parent compound and six metabolites were detected in the isolated bacterial samples compared with blank samples. Avicularin (M1) was anaerobic metabolized to its aglycone quercetin (M2) and methoxylated avicularin (M3, M4), then quercetin was converted to quercetin glycosides: quercetin-3-O-rhamnoside (M5), quercetin-3-O-glucoside (M6) and quercetin-7-O-glucoside (M7) by Bacillus sp. 46. The metabolic pathway and metabolites of avicularin by the intestinal bacterium Bacillus sp. 46 were reported for the first time. PMID:24463398

Zhao, Min; Xu, Jun; Qian, Dawei; Guo, Jianming; Jiang, Shu; Shang, Er-xin; Duan, Jin-ao; Yang, Jing; Du, Le-yue

2014-02-15

374

Intestinal microbiology in early life: specific prebiotics can have similar functionalities as human-milk oligosaccharides.  

PubMed

Human milk is generally accepted as the best nutrition for newborns and has been shown to support the optimal growth and development of infants. On the basis of scientific insights from human-milk research, a specific mixture of nondigestible oligosaccharides has been developed, with the aim to improve the intestinal microbiota in early life. The mixture has been extensively studied and has been shown to be safe and to have potential health benefits that are similar to those of human milk. The specific mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides has been found to affect the development of early microbiota and to increase the Bifidobacterium amounts as observed in human-milk-fed infants. The resulting gut ecophysiology is characterized by high concentrations of lactate, a slightly acidic pH, and specific short-chain fatty acid profiles, which are high in acetate and low in butyrate and propionate. Here, we have summarized the main findings of dietary interventions with these specific oligosaccharides on the gut microbiota in early life. The gut ecophysiology in early life may have consequences for the metabolic, immunologic, and even neurologic development of the child because reports increasingly substantiate the important function of gut microbes in human health. This review highlights major findings in the field of early gut colonization and the potential impact of early nutrition in healthy growth and development. PMID:23824728

Oozeer, Raish; van Limpt, Kees; Ludwig, Thomas; Ben Amor, Kaouther; Martin, Rocio; Wind, Richèle D; Boehm, Günther; Knol, Jan

2013-08-01

375

Characterization of Slackia exigua isolated from human wound infections, including abscesses of intestinal origin.  

PubMed

Eleven clinical strains isolated from infected wound specimens were subjected to polyphasic taxonomic analysis. Sequence analysis of the 16S rRNA gene showed that all 11 strains were phylogenetically related to Slackia exigua. Additionally, conventional and biochemical tests of 6 of the 11 strains were performed as supplementary methods to obtain phenotypic identification by comparison with the phenotypes of the relevant type strains. S. exigua has been considered an oral bacterial species in the family Coriobacteriaceae. This organism is fastidious and grows poorly, so it may easily be overlooked. The 16S rRNA gene sequences and the biochemical characteristics of four of the S. exigua strains isolated for this study from various infections indicative of an intestinal source were almost identical to those of the validated S. exigua type strain from an oral source and two of the S. exigua strains from oral sources evaluated in this study. Thus, we show for the first time that S. exigua species can be isolated from extraoral infections as well as from oral infections. The profiles of susceptibility to selected antimicrobials of this species were also investigated for the first time. PMID:20107092

Kim, Keun-Sung; Rowlinson, Marie-Claire; Bennion, Robert; Liu, Chengxu; Talan, David; Summanen, Paula; Finegold, Sydney M

2010-04-01

376

Characterization of Slackia exigua Isolated from Human Wound Infections, Including Abscesses of Intestinal Origin ?  

PubMed Central

Eleven clinical strains isolated from infected wound specimens were subjected to polyphasic taxonomic analysis. Sequence analysis of the 16S rRNA gene showed that all 11 strains were phylogenetically related to Slackia exigua. Additionally, conventional and biochemical tests of 6 of the 11 strains were performed as supplementary methods to obtain phenotypic identification by comparison with the phenotypes of the relevant type strains. S. exigua has been considered an oral bacterial species in the family Coriobacteriaceae. This organism is fastidious and grows poorly, so it may easily be overlooked. The 16S rRNA gene seq