scholarly journals In vitrocomparison of commensal, probiotic and pathogenic strains ofEnterococcus faecalis

2012 ◽  
Vol 108 (11) ◽  
pp. 2043-2053 ◽  
Author(s):  
Trine E. Christoffersen ◽  
Hanne Jensen ◽  
Charlotte R. Kleiveland ◽  
Guro Dørum ◽  
Morten Jacobsen ◽  
...  
Keyword(s):  
Health Benefit ◽  
Intestinal Epithelial ◽  
Binding Studies ◽  
Potential Health ◽  
Host Interactions ◽  
Starting Point ◽  
Different Strains ◽  
Micro Organisms

In vivostudies have provided evidence that micro-organisms have important roles in immunological, digestive and respiratory functions, conferring health benefits on the host. Severalin vitromethods have been advised for the initial screening of microbes with potential health effects. The objective of the present study was to employ suchin vitromethodology to characterise different strains ofEnterococcus faecalis. The characteristics of a commercial product marketed as a probiotic, Symbioflor-1 (Symbiopharm), were compared with the characteristics of both pathogenic and commensal strains. Tolerance towards low pH and viability after exposure to human gastric and duodenal juices were assayed. Symbioflor-1 was the most susceptible strain to these treatments when compared with the otherE. faecalisstrains. Furthermore, Symbioflor-1 exhibited the lowest adhesion capacity to intestinal epithelial cells (IEC) and mucus. Competitive binding studies using heparin indicated that glycosaminoglycans might be involved in the adhesion to IEC, but also that differences in these putative bacteria–host interactions do not cause the relative low adhesion capacity of Symbioflor-1. Maturation of dendritic cells (DC) after exposure to bacteria was assayed as an indication of an immunomodulatory effect. All strains induced a moderate elevation of the DC maturation markers CD83 and CD86; however, no strain-specific differences were detected. Correlations betweenin vitroandin vivostudies are discussed. Althoughin vitroassaying is a rational starting point for the selection of microbes with a potential health benefit, it is emphasised that human clinical trials are the definite tool for establishing probiotic status.

scholarly journals Heat-Labile Enterotoxin Promotes Escherichia coli Adherence to Intestinal Epithelial Cells

2008 ◽  
Vol 191 (1) ◽  
pp. 178-186 ◽  
Author(s):  
Amber M. Johnson ◽  
Radhey S. Kaushik ◽  
David H. Francis ◽  
James M. Fleckenstein ◽  
Philip R. Hardwidge
Keyword(s):  
Escherichia Coli ◽  
Surface Expression ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Host Interactions ◽  
Heat Labile ◽  
Vitro Model ◽  
Bacterial Sensing

ABSTRACT Given recent evidence suggesting that the heat-labile enterotoxin (LT) provides a colonization advantage for enterotoxigenic Escherichia coli (ETEC) in vivo, we hypothesized that LT preconditions the host intestinal epithelium for ETEC adherence. To test this hypothesis, we used an in vitro model of ETEC adherence to examine the role of LT in promoting bacterium-host interactions. We present data demonstrating that elaboration of LT promotes a significant increase in E. coli adherence. This phenotype is primarily dependent on the inherent ADP-ribosylation activity of this toxin, with a secondary role observed for the receptor-binding LT-B subunit. Rp-3′,5′-cyclic AMP (cAMP), an inhibitor of protein kinase A, was sufficient to abrogate LT's ability to promote subsequent bacterial adherence. Increased adherence was not due to changes in the surface expression of the host receptor for the K88ac adhesin. Evidence is also presented for a role for bacterial sensing of host-derived cAMP in promoting adherence to host cells.

VI.Entamoeba histolytica: parasite-host interactions

2001 ◽  
Vol 280 (6) ◽  
pp. G1049-G1054 ◽  
Author(s):  
Samuel L. Stanley ◽  
Sharon L. Reed
Keyword(s):  
Virulence Factors ◽  
Host Response ◽  
Host Cells ◽  
Intestinal Epithelial ◽  
Small Peptides ◽  
In Vivo Models ◽  
Host Interactions ◽  
Models Of Disease

The protozoan intestinal parasite Entamoeba histolytica remains a significant cause of morbidity and mortality worldwide. E. histolytica causes two major clinical syndromes, amebic colitis and amebic liver abscess. Recent advances in the development of in vitro and in vivo models of disease, new genetic approaches, the identification of key E. histolytica virulence factors, and the recognition of crucial elements of the host response to infection have led to significant insights into the pathogenesis of amebic infection. E. histolytica virulence factors include 1) a surface galactose binding lectin that mediates E. histolyticabinding to host cells and may contribute to amebic resistance to complement, 2) amebapores, small peptides capable of lysing cells, which may play a role in killing intestinal epithelial cells, hepatocytes, and host defense cells, and 3) a family of secreted cysteine proteinases that play a key role in E. histolytica tissue invasion, evasion of host defenses, and parasite induction of gut inflammation. Amebae can both lyse host cells and induce their suicide through programmed cell death. The host response is also an important factor in the outcome of infection, and neutrophils may play a key role in contributing to the tissue damage seen in amebiasis and in controlling amebic infection.

EVIDENCE from in VITRO and IN VIVO studies on the potential health REPERCUSSIONS of MICRO- and nanoplastics

Chemosphere ◽  
2021 ◽  
pp. 130826
Author(s):  
Anabel González-Acedo ◽  
Enrique García-Recio ◽  
Rebeca Illescas-Montes ◽  
Javier Ramos-Torrecillas ◽  
Lucía Melguizo-Rodríguez ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Potential Health

scholarly journals Newly Emerging Airborne Pollutants: Current Knowledge of Health Impact of Micro and Nanoplastics

2021 ◽  
Vol 18 (6) ◽  
pp. 2997
Author(s):  
Alessio Facciolà ◽  
Giuseppa Visalli ◽  
Marianna Pruiti Ciarello ◽  
Angela Di Pietro
Keyword(s):  
Surface Area ◽  
Current Knowledge ◽  
Oxidative Degradation ◽  
Health Impact ◽  
Outdoor Exposure ◽  
Environmental Matrices ◽  
Potential Health ◽  
Bodily Fluids

Plastics are ubiquitous persistent pollutants, forming the most representative material of the Anthropocene. In the environment, they undergo wear and tear (i.e., mechanical fragmentation, and slow photo and thermo-oxidative degradation) forming secondary microplastics (MPs). Further fragmentation of primary and secondary MPs results in nanoplastics (NPs). To assess potential health damage due to human exposure to airborne MPs and NPs, we summarize the evidence collected to date that, however, has almost completely focused on monitoring and the effects of airborne MPs. Only in vivo and in vitro studies have assessed the toxicity of NPs, and a standardized method for their analysis in environmental matrices is still missing. The main sources of indoor and outdoor exposure to these pollutants include synthetic textile fibers, rubber tires, upholstery and household furniture, and landfills. Although both MPs and NPs can reach the alveolar surface, the latter can pass into the bloodstream, overcoming the pulmonary epithelial barrier. Despite the low reactivity, the number of surface area atoms per unit mass is high in MPs and NPs, greatly enhancing the surface area for chemical reactions with bodily fluids and tissue in direct contact. This is proven in polyvinyl chloride (PVC) and flock workers, who are prone to persistent inflammatory stimulation, leading to pulmonary fibrosis or even carcinogenesis.

scholarly journals Porcine small intestinal organoids as a model to explore ETEC–host interactions in the gut

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Bjarne Vermeire ◽  
Liara M. Gonzalez ◽  
Robert J. J. Jansens ◽  
Eric Cox ◽  
Bert Devriendt
Keyword(s):  
Intestinal Epithelial ◽  
Gut Health ◽  
Functional Responses ◽  
Host Pathogen Interactions ◽  
Epithelial Surface ◽  
Host Interactions ◽  
Intestinal Organoids ◽  
Host Pathogen ◽  
Small Intestinal

AbstractSmall intestinal organoids, or enteroids, represent a valuable model to study host–pathogen interactions at the intestinal epithelial surface. Much research has been done on murine and human enteroids, however only a handful studies evaluated the development of enteroids in other species. Porcine enteroid cultures have been described, but little is known about their functional responses to specific pathogens or their associated virulence factors. Here, we report that porcine enteroids respond in a similar manner as in vivo gut tissues to enterotoxins derived from enterotoxigenic Escherichia coli, an enteric pathogen causing postweaning diarrhoea in piglets. Upon enterotoxin stimulation, these enteroids not only display a dysregulated electrolyte and water balance as shown by their swelling, but also secrete inflammation markers. Porcine enteroids grown as a 2D-monolayer supported the adhesion of an F4+ ETEC strain. Hence, these enteroids closely mimic in vivo intestinal epithelial responses to gut pathogens and are a promising model to study host–pathogen interactions in the pig gut. Insights obtained with this model might accelerate the design of veterinary therapeutics aimed at improving gut health.

scholarly journals EJE Prize 2013: Regulation of aldosterone secretion: from physiology to disease

2013 ◽  
Vol 168 (6) ◽  
pp. R85-R93 ◽  
Author(s):  
Felix Beuschlein
Keyword(s):  
High Throughput Sequencing ◽  
Secondary Hypertension ◽  
Small Sample ◽  
Cellular Systems ◽  
Common Disease ◽  
Aldosterone Secretion ◽  
Technical Developments ◽  
Starting Point

Arterial hypertension is a major cardiovascular risk factor that affects between 10 and 40% of the population in industrialized countries. Primary aldosteronism (PA) is the most common form of secondary hypertension with an estimated prevalence of around 10% in referral centers and 4% in a primary care setting. Despite its high prevalence until recently, the underlying genetic and molecular basis of this common disease had remained largely obscure. Over the past decade, a number of insights have been achieved that have relied onin vitrocellular systems, wild-type and genetically modifiedin vivomodels, as well as clinical studies in well-characterized patient populations. This progress has been made possible by a number of independent technical developments including that of specific hormone assays that allow measurement in small sample volumes as well as genetic techniques that enable high-throughput sequencing of a large number of samples. Furthermore, animal models have provided important insights into the physiology of aldosterone regulation that have served as a starting point for investigation of mechanisms involved in autonomous aldosterone secretion. Finally, national and international networks that have built up registries and biobanks have been instrumental in fostering translational research endeavors in PA. Therefore, it is to be expected that in the near future, further pathophysiological mechanisms that result in autonomous aldosterone secretion will be unraveled.

scholarly journals Fiber-Optic Time-Resolved Fluorescence Sensor for in Vitro Serotonin Determination

1993 ◽  
Vol 47 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Stephane Mottin ◽  
Canh Tran-Minh ◽  
Pierre Laporte ◽  
Raymond Cespuglio ◽  
Michel Jouvet
Keyword(s):  
Chemical Sensor ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Excitation Wavelength ◽  
Nitrogen Laser ◽  
Time Resolved ◽  
Temporal Effects ◽  
Starting Point

At pH 7 and with the excitation at wavelengths above 315 nm, previously unreported fluorescence of 5-HT (5-hydroxytryptamine) is observed. Two fluorescence bands were observed for 5-HT; the first emits at around 390 nm with an associated lifetime near 1 ns, and the other (well known) emits at 340 nm with an associated lifetime of 2.7 ns. With both static and time-resolved fluorescences, the spectral and temporal effects of the excitation wavelength were studied between 285 and 340 nm. With these basic spectroscopic properties as a starting point, a fiber-optic chemical sensor (FOCS) was developed in order to measure 5-HT with a single-fiber configuration, nitrogen laser excitation, and fast digitizing techniques. Temporal effects including fluorescence of the optical fiber were studied and compared with measurements both directly in cuvette and through the fiber-optic sensor. Less than thirty seconds are required for each measurement. A detection limit of 5-HT is reached in the range of 5 μM. Our system, with an improved sensitivity, could therefore be a possible and convenient “tool” for in vivo determination of 5-HT.

Progastrin1–80stimulates growth of intestinal epithelial cells in vitro via high-affinity binding sites

2003 ◽  
Vol 284 (2) ◽  
pp. G328-G339 ◽  
Author(s):  
P. Singh ◽  
X. Lu ◽  
S. Cobb ◽  
B. T. Miller ◽  
N. Tarasova ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Binding Sites ◽  
Intestinal Epithelial Cells ◽  
Full Length ◽  
Intestinal Epithelial ◽  
Growth Effects ◽  
High Affinity ◽  
Significant Difference

Proliferation and carcinogenesis of the large intestinal epithelial cells (IEC) cells is significantly increased in transgenic mice that overexpress the precursor progastrin (PG) peptide. It is not known if the in vivo growth effects of PG on IEC cells are mediated directly or indirectly. Full-length recombinant human PG (rhPG1–80) was generated to examine possible direct effects of PG on IEC cells. Surprisingly, rhPG (0.1–1.0 nM) was more effective than the completely processed gastrin 17 (G17) peptide as a growth factor. Even though IEC cells did not express CCK1and CCK2receptors (-R), fluorescently labeled G17 and Gly-extended G17 (G-Gly) were specifically bound to the cells, suggesting the presence of binding proteins other than CCK1-R and CCK2-R on IEC cells. High-affinity ( Kd= 0.5–1.0 nM) binding sites for125I-rhPG were discovered on IEC cells that demonstrated relative binding affinity for gastrin-like peptides in the order PG ≥ COOH-terminally extended G17 ≥ G-Gly > G17 > *CCK-8 (* significant difference; P< 0.05). In conclusion, our studies demonstrate for the first time direct growth effects of the full-length precursor peptide on IEC cells in vitro that are apparently mediated by the high-affinity PG binding sites that were discovered on these cells.

Effects of lactoferrin on intestinal epithelial cell growth and differentiation: an in vivo and in vitro study

BioMetals ◽  
2014 ◽  
Vol 27 (5) ◽  
pp. 857-874 ◽  
Author(s):  
Anne Blais ◽  
Cuibai Fan ◽  
Thierry Voisin ◽  
Najat Aattouri ◽  
Michel Dubarry ◽  
...  
Keyword(s):  
Cell Growth ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
In Vitro Study ◽  
Vitro Study ◽  
Intestinal Epithelial ◽  
Cell Growth And Differentiation

scholarly journals ADR1-Mediated Transcriptional Activation Requires the Presence of an Intact TFIID Complex

1998 ◽  
Vol 18 (10) ◽  
pp. 5861-5867 ◽  
Author(s):  
Philip B. Komarnitsky ◽  
Edward R. Klebanow ◽  
P. Anthony Weil ◽  
Clyde L. Denis
Keyword(s):  
Transcriptional Activation ◽  
Yeast Cells ◽  
Binding Studies ◽  
Whole Cell ◽  
Transactivation Domains ◽  
Cell Extracts ◽  
Genes Expression ◽  
Tfiid Complex

ABSTRACT The yeast transcriptional activator ADR1, which is required forADH2 and other genes’ expression, contains four transactivation domains (TADs). While previous studies have shown that these TADs act through GCN5 and ADA2, and presumably TFIIB, other factors are likely to be involved in ADR1 function. In this study, we addressed the question of whether TFIID is also required for ADR1 action. In vitro binding studies indicated that TADI of ADR1 was able to retain TAFII90 from yeast extracts and TADII could retain TBP and TAFII130/145. TADIV, however, was capable of retaining multiple TAFIIs, suggesting that TADIV was binding TFIID from yeast whole-cell extracts. The ability of TADIV truncation derivatives to interact with TFIID correlated with their transcription activation potential in vivo. In addition, the ability of LexA-ADR1-TADIV to activate transcription in vivo was compromised by a mutation in TAFII130/145. ADR1 was found to associate in vivo with TFIID in that immunoprecipitation of either TAFII90 or TBP from yeast whole-cell extracts specifically coimmunoprecipitated ADR1. Most importantly, depletion of TAFII90 from yeast cells dramatically reducedADH2 derepression. These results indicate that ADR1 physically associates with TFIID and that its ability to activate transcription requires an intact TFIID complex.

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