scholarly journals Functional modulation of enterocytes by gram-positive and gram-negative microorganisms

2004 ◽  
Vol 286 (4) ◽  
pp. G613-G626 ◽  
Author(s):  
Jan-Michel Otte ◽  
Daniel K. Podolsky
Keyword(s):  
Molecular Mechanisms ◽  
Protein S ◽  
Probiotic Bacteria ◽  
Intestinal Epithelial ◽  
Gram Positive ◽  
Epithelial Surface ◽  
Single Strain ◽  
Gram Negative ◽  
Cell Extracts ◽  
Mucin Expression

Clinical studies have suggested that so-called probiotic bacteria may be effective as therapy in inflammatory bowel disease. However, the molecular mechanisms of their interaction with the intestinal surface remain undefined. The influence of whole probiotic bacteria [ Escherichia coli Nissle 1917 (EcN); probiotic mixture VSL#3 (PM)], bacterial cell lysates, and conditioned media on transepithelial resistance (TER), IL-8 secretion, mucin gene expression, and tight junction proteins were determined in T84 and HT-29 intestinal epithelial cells (IEC). In addition, effects on pathogen ( Salmonella dublin)-induced alterations were analyzed. EcN as well as debris and cell extracts induced IL-8 secretion from IEC, whereas no such effect was observed following incubation with the PM. The PM and soluble protein(s) released from the PM increased TER, prevented pathogen-induced decrease in TER, and were shown to stabilize tight junctions. The PM induced expression of mucins in IEC, and these organisms as well as EcN diminished S. dublin-induced cell death. Inhibition of MAPKs with PD-98059 or SB-203580 significantly decreased alterations in IL-8 synthesis and mucin expression and affected the regulation of TER. Probiotics and protein(s) released by these organisms may functionally modulate the intestinal epithelium of the host by different mechanisms, including the competition of whole organisms for contact with the epithelial surface as well as stabilization of the cytoskeleton and barrier function and the induction of mucin expression. Gram-negative and gram-positive organisms differ in the mechanisms activated, and a combination of organisms might be more effective than the application of a single strain.

scholarly journals Resistin-like molecule β is a bactericidal protein that promotes spatial segregation of the microbiota and the colonic epithelium

2017 ◽  
Vol 114 (42) ◽  
pp. 11027-11033 ◽  
Author(s):  
Daniel C. Propheter ◽  
Andrew L. Chara ◽  
Tamia A. Harris ◽  
Kelly A. Ruhn ◽  
Lora V. Hooper
Keyword(s):  
Spatial Segregation ◽  
Gram Negative Bacteria ◽  
Intestinal Epithelial ◽  
Mucus Layer ◽  
Epithelial Surface ◽  
Gram Negative ◽  
Bacterial Membranes ◽  
Metabolic Functions ◽  
Mucosal Tissues ◽  
Human Resistin

The mammalian intestine is colonized by trillions of bacteria that perform essential metabolic functions for their hosts. The mutualistic nature of this relationship depends on maintaining spatial segregation between these bacteria and the intestinal epithelial surface. This segregation is achieved in part by the presence of a dense mucus layer at the epithelial surface and by the production of antimicrobial proteins that are secreted by epithelial cells into the mucus layer. Here, we show that resistin-like molecule β (RELMβ) is a bactericidal protein that limits contact between Gram-negative bacteria and the colonic epithelial surface. Mouse and human RELMβ selectively killed Gram-negative bacteria by forming size-selective pores that permeabilized bacterial membranes. In mice lacking RELMβ, Proteobacteria were present in the inner mucus layer and invaded mucosal tissues. Another RELM family member, human resistin, was also bactericidal, suggesting that bactericidal activity is a conserved function of the RELM family. Our findings thus identify the RELM family as a unique family of bactericidal proteins and show that RELMβ promotes host–bacterial mutualism by regulating the spatial segregation between the microbiota and the intestinal epithelium.

scholarly journals IFN-mediated negative feedback supports bacteria class-specific macrophage inflammatory responses

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Rachel A Gottschalk ◽  
Michael G Dorrington ◽  
Bhaskar Dutta ◽  
Kathleen S Krauss ◽  
Andrew J Martins ◽  
...  
Keyword(s):  
Negative Feedback ◽  
Molecular Mechanisms ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Type I ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Despite existing evidence for tuning of innate immunity to different classes of bacteria, the molecular mechanisms used by macrophages to tailor inflammatory responses to specific pathogens remain incompletely defined. By stimulating mouse macrophages with a titration matrix of TLR ligand pairs, we identified distinct stimulus requirements for activating and inhibitory events that evoked diverse cytokine production dynamics. These regulatory events were linked to patterns of inflammatory responses that distinguished between Gram-positive and Gram-negative bacteria, both in vitro and after in vivo lung infection. Stimulation beyond a TLR4 threshold and Gram-negative bacteria-induced responses were characterized by a rapid type I IFN-dependent decline in inflammatory cytokine production, independent of IL-10, whereas inflammatory responses to Gram-positive species were more sustained due to the absence of this IFN-dependent regulation. Thus, disparate triggering of a cytokine negative feedback loop promotes tuning of macrophage responses in a bacteria class-specific manner and provides context-dependent regulation of inflammation dynamics.

scholarly journals Evaluation of Verigene Blood Culture Test Systems for Rapid Identification of Positive Blood Cultures

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Jae-Seok Kim ◽  
Go-Eun Kang ◽  
Han-Sung Kim ◽  
Hyun Soo Kim ◽  
Wonkeun Song ◽  
...  
Keyword(s):  
Blood Culture ◽  
Resistance Genes ◽  
Rapid Identification ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Single Strain ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Susceptibility Tests

The performance of molecular tests using the Verigene Gram-Positive and Gram-Negative Blood Culture nucleic acid tests (BC-GP and BC-GN, resp.; Naosphere, Northbrook, IL, USA) was evaluated for the identification of microorganisms detected from blood cultures. Ninety-nine blood cultures containing Gram-positive bacteria and 150 containing Gram-negative bacteria were analyzed using the BC-GP and BC-GN assays, respectively. Blood cultures were performed using the Bactec blood culture system (BD Diagnostic Systems, Franklin Lakes, NJ, USA) and conventional identification and antibiotic-susceptibility tests were performed using a MicroScan system (Siemens, West Sacramento, CA, USA). When a single strain of bacteria was isolated from the blood culture, Verigene assays correctly identified 97.9% (94/96) of Gram-positive bacteria and 93.8% (137/146) of Gram-negative bacteria. Resistance genesmecAandvanAwere correctly detected by the BC-GP assay, while the extended-spectrumβ-lactamase CTX-M and the carbapenemase OXA resistance gene were detected from 30 cases cultures by the BC-GN assay. The BC-GP and BC-GN assays showed high agreement with conventional identification and susceptibility tests. These tests are useful for rapid identification of microorganisms and the detection of clinically important resistance genes from positive Bactec blood cultures.

The effect of chromic oxide (Cr2O3) on aerobic bacterial populations associated with the intestinal epithelial mucosa of Arctic charr, Salvelinus alpinus (L.)

1993 ◽  
Vol 39 (12) ◽  
pp. 1169-1173 ◽  
Author(s):  
Einar Ringø
Keyword(s):  
Heterotrophic Bacteria ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Bacterial Flora ◽  
Chromic Oxide ◽  
Intestinal Epithelial ◽  
Gram Positive ◽  
Bacterial Populations ◽  
Gram Negative ◽  
Attachment Sites

Populations of aerobic heterotrophic bacteria present in the gastrointestinal tract of healthy Arctic charr, Salvelinus alpinus (L.), were estimated using the dilution plate technique. The gastrointestinal bacterial flora of fish fed an unsupplemented diet was dominated by Gram-negative bacteria of the genera Acinetobacter, Aeromonas, Agrobacterium, Alcaligenes, Cytophaga, Flavobacterium, Pseudomonas, and Vibrio, and Gram-positive bacteria of the genera Arthrobacter, Brevibacterium, Corynebacterium, Kurthia, Lactobacillus, Microbacterium, Micrococcus, Staphylococcus, and Streptococcus. The composition of the indigenous aerobic bacterial flora in the digestive tract, and especially the microorganisms isolated from the midgut and hindgut regions, was affected by inclusion of 1% chromic oxide (Cr2O3) in the diet. Many of the Gram-negative bacterial genera and some of the Gram-positive bacterial genera were not detectable in the Cr2O3-fed fish. The midgut and hindgut regions in the Cr2O3-fed fish were dominated by Gram-positive microorganisms of the genera Lactobacillus and Streptococcus. It is suggested that the increased accumulation of Cr2O3 in the alimentary tract, as dietary compounds are removed, affects the attachment sites for the gastrointestinal microflora or affects the gut epithelium directly.Key words: chromic oxide, aerobic bacterial flora, Arctic charr.

Transcriptomic response of immune signalling pathways in intestinal epithelial cells exposed to lipopolysaccharides, Gram-negative bacteria or potentially probiotic microbes

2012 ◽  
Vol 3 (4) ◽  
pp. 273-286 ◽  
Author(s):  
J. Audy ◽  
O. Mathieu ◽  
J. Belvis ◽  
T.A. Tompkins
Keyword(s):  
Epithelial Cells ◽  
Host Response ◽  
Intestinal Epithelial Cells ◽  
Mitogen Activated Protein Kinase ◽  
Gram Negative Bacteria ◽  
Intestinal Epithelial ◽  
Gram Positive ◽  
Transcriptomic Response ◽  
Gram Negative ◽  
The Impact

In order to understand the appropriate use of potentially probiotic Gram-positive microbes through their introduction in the gut microbiome, it is necessary to understand the influence of individual bacteria on the host-response system at a cellular level. In the present study, we have shown that lipopolysaccharides, flagellated Gram-negative bacteria, potentially probiotic Gram-positive bacteria and yeast interact differently with human intestinal epithelial cells with a custom-designed expression microarray evaluating 17 specific host-response pathways. Only lipopolysaccharides and flagellated Gram-negative bacteria induced inflammatory response, while a subset of Gram-positive microbes had anti-inflammatory potential. The main outcome from the study was the differential regulation of the central mitogen-activated protein kinase signalling pathway by these Gram-positive microbes versus commensal/pathogenic Gram-negative bacteria. The microarray was efficient to highlight the impact of individual bacteria on the response of intestinal epithelial cells, but quantitative real-time polymerase chain reaction validation demonstrated some underestimation for down-regulated genes by the microarray. This immune array will allow us to better understand the mechanisms underlying microbe-induced host immune responses.

scholarly journals Patterns of cytokine induction by gram-positive and gram-negative probiotic bacteria

2004 ◽  
Vol 42 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Martin L. Cross ◽  
Anja Ganner ◽  
Diaa Teilab ◽  
Linley M. Fray
Keyword(s):  
Probiotic Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Cytokine Induction

scholarly journals A Cyclic Di-GMP Network Is Present in Gram-Positive Streptococcus and Gram-Negative Proteus Species

2020 ◽  
Author(s):  
Ying Liu ◽  
Changhan Lee ◽  
Fengyang Li ◽  
Janja Trček ◽  
Heike Bähre ◽  
...  
Keyword(s):  
Physiological Activity ◽  
Open Reading Frames ◽  
Homology Search ◽  
Gram Positive ◽  
Gram Negative ◽  
Cell Extracts ◽  
Diguanylate Cyclases ◽  
Exopolysaccharide Biosynthesis ◽  
Reading Frames ◽  
Respective Species

Cyclic di-GMP is a ubiquitous second messenger in bacteria. This work describes the occurrence of a cyclic di-GMP signaling network in Gram-positive <i>Streptococcus </i>species and Gram-negative <i>Proteus</i>. After identification of candidate diguanylate cyclases by homology search in the respective species, the open reading frames were cloned and proteins expressed. Production of cyclic di-GMP was demonstrated by riboswitch assays, detection of cyclic di-GMP in cell lysates by MALDI-FTMS and in cell extracts by standard LC-MS/MS. Expression of the diguanylate cyclases in the heterologous host Salmonella typhimurium showed the expected physiological activity, namely up regulation of biofilm formation and down regulation of motility. The co-localisation of both sole diguanylate cyclases with cellulose or cellulose-like synthases indicates exopolysaccharide biosynthesis to be a conserved trait of cyclic di-GMP signaling.

scholarly journals Methylation of Halogenated Phenols and Thiophenols by Cell Extracts of Gram-Positive and Gram-Negative Bacteria

1988 ◽  
Vol 54 (2) ◽  
pp. 524-530 ◽  
Author(s):  
Alasdair H. Neilson ◽  
Carin Lindgren ◽  
Per-Åke Hynning ◽  
Mikael Remberger
Keyword(s):  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Cell Extracts ◽  
Halogenated Phenols

scholarly journals Lipoteichoic Acids from Lactobacillus johnsonii Strain La1 and Lactobacillus acidophilus Strain La10 Antagonize the Responsiveness of Human Intestinal Epithelial HT29 Cells to Lipopolysaccharide and Gram-Negative Bacteria

2002 ◽  
Vol 70 (4) ◽  
pp. 2057-2064 ◽  
Author(s):  
Karine Vidal ◽  
Anne Donnet-Hughes ◽  
Dominique Granato
Keyword(s):  
Human Milk ◽  
Proinflammatory Cytokines ◽  
Lactobacillus Acidophilus ◽  
Gram Negative Bacteria ◽  
Intestinal Epithelial ◽  
Lactobacillus Johnsonii ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Lipoteichoic Acids

ABSTRACT Intestinal epithelial cells (IECs) respond to lipopolysaccharide (LPS) from gram-negative bacteria in the presence of the soluble form of CD14 (sCD14), a major endotoxin receptor. Since sCD14 is also known to interact with gram-positive bacteria and their components, we looked at whether sCD14 could mediate their effects on human IECs. To this end, we examined the production of proinflammatory cytokines following exposure of the IECs to specific gram-positive bacteria or their lipoteichoic acids (LTAs) in the absence and presence of human milk as a source of sCD14. In contrast to LPS from Escherichia coli or Salmonella enteritidis, neither the gram-positive bacteria Lactobacillus johnsonii strain La1 and Lactobacillus acidophilus strain La10 nor their LTAs stimulated IECs, even in the presence of sCD14. However, both LTAs inhibited the sCD14-mediated LPS responsiveness of IECs. We have previously hypothesized that sCD14 in human milk is a means by which the neonate gauges the bacterial load in the intestinal lumen and liberates protective proinflammatory cytokines from IECs. The present observations suggest that gram-positive organisms, via their LTAs, temper this response and prevent an exaggerated inflammatory response.

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