scholarly journals Role of FliF and FliI of Listeria monocytogenes in Flagellar Assembly and Pathogenicity

2005 ◽  
Vol 73 (9) ◽  
pp. 5530-5539 ◽  
Author(s):  
Armelle Bigot ◽  
Hélène Pagniez ◽  
Eléonore Botton ◽  
Claude Fréhel ◽  
Iharilalao Dubail ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Epithelial Cells ◽  
Bacterial Motility ◽  
Deletion Mutants ◽  
Intestinal Pathogens ◽  
Flagellar Assembly ◽  
Body Component ◽  
Intracellular Multiplication ◽  
A Minor

ABSTRACT Flagellar structures have been shown to participate in virulence in a variety of intestinal pathogens. Here, we have identified two potential flagellar genes of Listeria monocytogenes: lmo0713, encoding a protein similar to the flagellar basal body component FliF, and lmo0716, encoding a protein similar to FliI, the cognate ATPase energizing the flagellar export apparatus. Expression of fliF and fliI appears to be downregulated at 37°C, like that of flaA, encoding flagellin. By constructing two chromosomal deletion mutants, we show that inactivation of either fliF or fliI (i) abolishes bacterial motility and flagella production, (ii) impairs adhesion and entry into nonphagocytic epithelial cells, and (iii) also reduces uptake by bone marrow-derived macrophages. However, the ΔfliF and ΔfliI mutations have only a minor impact on bacterial virulence in the mouse model, indicating that the flagellar secretion apparatus itself is not essential for survival in this animal model. Finally, among 100 human clinical isolates of L. monocytogenes tested, we found 20 strains still motile at 37°C. Notably, all these strains adhered less efficiently than strain EGD-e to Caco-2 cells at 37°C but showed no defect of intracellular multiplication. These data suggest that expression of the flagella at 37°C might hinder optimal adhesion to epithelial cells but has no impact on intracytosolic survival of L. monocytogenes.

scholarly journals Intracellular Survival of Neisseria gonorrhoeae in Male Urethral Epithelial Cells: Importance of a Hexaacyl Lipid A

2002 ◽  
Vol 70 (2) ◽  
pp. 909-920 ◽  
Author(s):  
Deborah M. B. Post ◽  
Nancy J. Phillips ◽  
Jian Q. Shao ◽  
David D. Entz ◽  
Bradford W. Gibson ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Neisseria Gonorrhoeae ◽  
Parent Strain ◽  
Lipid A ◽  
Insertion Mutation ◽  
Intracellular Killing ◽  
Lipid A Structure ◽  
Males And Females ◽  
A Minor

ABSTRACT Neisseria gonorrhoeae is a strict human pathogen that invades and colonizes the urogenital tracts of males and females. Lipooligosaccharide (LOS) has been shown to play a role in gonococcal pathogenesis. The acyl transferase MsbB is involved in the biosynthesis of the lipid A portion of the LOS. In order to determine the role of an intact lipid A structure on the pathogenesis of N. gonorrhoeae, the msbB gene was cloned and sequenced, a deletion and insertion mutation was introduced into N. gonorrhoeae, and the mutant strain was designated 1291A11K3. Mass spectrometric analyses of 1291A11K3 LOS determined that this mutation resulted in a pentaacyl rather than a hexaacyl lipid A structure. These analyses also demonstrated an increase in the phosphorylation of lipid A and an increase in length of the oligosaccharide of a minor species of the msbB LOS. The interactions of this mutant with male urethral epithelial cells (uec) were examined. Transmission and scanning electron microscopy studies indicated that the msbB mutants formed close associations with and were internalized by the uec at levels similar to those of the parent strain. Gentamicin survival assays performed with 1291A11K3 and 1291 bacteria demonstrated that there was no difference in the abilities of the two strains to adhere to uec; however, significantly fewer 1291A11K3 bacteria than parent strain bacteria were recovered from gentamicin-treated uec. These studies suggest that the lipid A modification in the N. gonorrhoeae msbB mutant may render it more susceptible to innate intracellular killing mechanisms when internalized by uec.

scholarly journals Lrp5 Has a Wnt-Independent Role in Glucose Uptake and Growth for Mammary Epithelial Cells

2015 ◽  
Vol 36 (6) ◽  
pp. 871-885 ◽  
Author(s):  
Emily N. Chin ◽  
Joshua A. Martin ◽  
Soyoung Kim ◽  
Saja A. Fakhraldeen ◽  
Caroline M. Alexander
Keyword(s):  
Epithelial Cells ◽  
Wnt Signaling ◽  
Glucose Uptake ◽  
Mammary Epithelial Cells ◽  
Glucose Consumption ◽  
Mammary Epithelial ◽  
Loss Of Function ◽  
Consumption Rates ◽  
A Minor

Lrp5 is typically described as a Wnt signaling receptor, albeit a less effective Wnt signaling receptor than the better-studied sister isoform, Lrp6. Here we show that Lrp5 is only a minor player in the response to Wnt3a-type ligands in mammary epithelial cells; instead, Lrp5 is required for glucose uptake, and glucose uptake regulates the growth rate of mammary epithelial cells in culture. Thus, a loss of Lrp5 leads to profound growth suppression, whether growth is induced by serum or by specific growth factors, and this inhibition is not due to a loss of Wnt signaling. Depletion of Lrp5 decreases glucose uptake, lactate secretion, and oxygen consumption rates; inhibition of glucose consumption phenocopies the loss of Lrp5 function. Both Lrp5 knockdown and low external glucose induce mitochondrial stress, as revealed by the accumulation of reactive oxygen species (ROS) and the activation of the ROS-sensitive checkpoint, p38α. In contrast, loss of function of Lrp6 reduces Wnt responsiveness but has little impact on growth. This highlights the distinct functions of these two Lrp receptors and an important Wnt ligand-independent role of Lrp5 in glucose uptake in mammary epithelial cells.

scholarly journals Listeria monocytogenes σB Contributes to Invasion of Human Intestinal Epithelial Cells

2004 ◽  
Vol 72 (12) ◽  
pp. 7374-7378 ◽  
Author(s):  
Heesun Kim ◽  
Kathryn J. Boor ◽  
Hélène Marquis
Keyword(s):  
Listeria Monocytogenes ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cells

ABSTRACT The role of σB in Listeria monocytogenes infection of human intestinal epithelial cells was investigated. Invasion defects associated with loss of σB paralleled those of a ΔinlA strain independently of the σB-dependent P2 prfA promoter. Concomitantly, amounts of inlA transcript and InlA protein were significantly decreased in the ΔsigB strain.

scholarly journals Role of FliF and FliI of Listeria monocytogenes in Flagellar Assembly and Pathogenicity

2007 ◽  
Vol 75 (2) ◽  
pp. 1063-1064
Author(s):  
Armelle Bigot ◽  
Hélène Pagniez ◽  
Eléonore Botton ◽  
Claude Fréhel ◽  
Iharilalao Dubail ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Flagellar Assembly

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

1982 ◽  
Vol 40 ◽  
pp. 132-133
Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Replication Rate ◽  
Enzymatic Dissociation ◽  
Growth Assay ◽  
Epidermal Growth ◽  
Fetal Bovine ◽  
Esophageal Epithelial Cells ◽  
Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Role of Bronchial Epithelial Cells in Pathogenesis of COPD

Pneumologie ◽  
2011 ◽  
Vol 65 (12) ◽  
Author(s):  
S Rim ◽  
S Jahan ◽  
G John ◽  
K Kohse ◽  
A Bohla ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Bronchial Epithelial Cells ◽  
Bronchial Epithelial

THE ROLE OF ANTHROPONYMS IN THE SEMANTIC FIELD OF ARTISTIC WORKS

2019 ◽  
Vol 2019 (29) ◽  
pp. 66-77
Author(s):  
Lidiya Derbenyova
Keyword(s):  
Literary Work ◽  
Main Theme ◽  
Semantic Field ◽  
New Meanings ◽  
Minor Part ◽  
The One ◽  
A Minor ◽  
And Storage ◽  
Horizon Of Expectations

The article explores the role of antropoetonyms in the reader’s “horizon of expectation” formation. As a kind of “text in the text”, antropoetonyms are concentrating a large amount of information on a minor part of the text, reflecting the main theme of the work. As a “text” this class of poetonyms performs a number of functions: transmission and storage of information, generation of new meanings, the function of “cultural memory”, which explains the readers’ “horizon of expectations”. In analyzing the context of the literary work we should consider the function of antropoetonyms in vertical context (the link between artistic and other texts, and the groundwork system of culture), as well as in the context of the horizontal one (times’ connection realized in the communication chain from the word to the text; the author’s intention). In this aspect, the role of antropoetonyms in the structure of the literary text is extremely significant because antropoetonyms convey an associative nature, generating a complex mechanism of allusions. It’s an open fact that they always transmit information about the preceding text and suggest a double decoding. On the one hand, the recipient decodes this information, on the other – accepts this as a sort of hidden, “secret” sense.

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