The effect of chitosan and other polycations on tight junction permeability in the human intestinal Caco-2 cell line1 1Abbreviations: AP = apical; BL = basolateral; 2-DOG = 2-deoxyglucose; HBSS = Hanks balanced salt solution; FITC = fluorescein isothiocyanate; HEPES = N-2-hydroxyethyl piperazine-N-4-butanesulfonic acid; HMW = high molecular weight; LMW = low molecular weight; MES = morpholinoethane sulfonic acid; PBS+ = phosphate buffered saline; PEI = polyethylenimine; TEER = trans-epithelial electrical resistance; TRITC = tetramethylrodamine isothiocyanate.

ABSTRACT The nonstructural NSP4 protein of rotavirus has been described as the first viral enterotoxin. In this study we have examined the effect of NSP4 on polarized epithelial cells (MDCK-1) grown on permeable filters. Apical but not basolateral administration of NSP4 was found to cause a reduction in the transepithelial electrical resistance, redistribution of filamentous actin, and an increase in paracellular passage of fluorescein isothiocyanate-dextran. Significant effects on transepithelial electrical resistance were noted after a 20- to 30-h incubation with 1 nmol of NSP4. Most surprisingly, the epithelium recovered its original integrity and electrical resistance upon removal of NSP4. Preincubation of nonconfluent MDCK-1 cells with NSP4 prevented not only development of a permeability barrier but also lateral targeting of the tight-junction-associated Zonula Occludens-1 (ZO-1) protein. Taken together, these data indicate new and specific effects of NSP4 on tight-junction biogenesis and show a novel effect of NSP4 on polarized epithelia.

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The Retrieval and Use of Components from AMPS Production Residue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.356-360.2060 ◽

2011 ◽

Vol 356-360 ◽

pp. 2060-2064

Author(s):

Hai Jing Wang ◽

Jin Sheng Feng

Keyword(s):

Molecular Weight ◽

Sulfonic Acid ◽

Raw Materials ◽

Low Molecular Weight ◽

Surface Active Agents ◽

External Standard Method ◽

Reinforcing Agent ◽

External Standard ◽

Surface Active ◽

Flocculating Agent

2-acrylamido-2-methylpropane sulfonic acid (AMPS) is commonly used in the synthesis of polyacrylamide which is widely used as surface-active agents, water treatment chemicals and oil-displacing agents. In the production process of AMPS, there are some byproducts. In this paper, the residue from AMPS production is analyzed. The main byproducts in the residue are ascertained by means of HPLC and ESI-MS, which are butylacrylamide (TBAA) and acrylamide. By external standard method, the residue is analyzed quantitatively. Using the residue as raw materials, a kind of polyacrylamide with low molecular weight is synthesized, which can be used as paper reinforcing agent or emulsifier. After the residue is purified, the high molecular weight polyacrylamide is synthesized, which can be used as flocculating agent or oil-displacing agent.

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Apparent endocytosis of fluorescein isothiocyanate-conjugated dextran by Saccharomyces cerevisiae reflects uptake of low molecular weight impurities, not dextran.

The Journal of Cell Biology ◽

10.1083/jcb.105.5.1981 ◽

1987 ◽

Vol 105 (5) ◽

pp. 1981-1987 ◽

Cited By ~ 46

Author(s):

R A Preston ◽

R F Murphy ◽

E W Jones

Keyword(s):

Saccharomyces Cerevisiae ◽

Molecular Weight ◽

Lucifer Yellow ◽

Ph Dependence ◽

Fluid Phase ◽

Fluorescein Isothiocyanate ◽

Low Molecular Weight ◽

Yeast Saccharomyces Cerevisiae ◽

Fluid Phase Endocytosis ◽

Rapid Kinetics

Concurrent with Riezman's report (Riezman, H. 1985, Cell. 40:1001-1009) that fluid-phase endocytosis of the small molecule Lucifer yellow occurs in the yeast Saccharomyces cerevisiae, Makarow (Makarow, M. 1985. EMBO [Eur. Mol. Biol. Organ.] J. 4:1861-1866) reported the endocytotic uptake of 70-kD FITC-dextran (FD) and its subsequent compartmentation into the yeast vacuole. Samples of FD synthesized and purified here failed to label yeast vacuoles under conditions that allowed labeling using commercial FD. Chromatography revealed that the commercial FD was heavily contaminated with at least three low molecular weight fluorescent compounds. Dialysis was ineffective for removing the contaminants. After purification (Sephadex G25, ethanol extraction), commercial FD was incapable of labeling vacuoles. Extracts of cells labeled with partially purified FD contained FITC, not FD, based on Sephadex and thin layer chromatography. In either the presence or absence of unlabeled 70-kD dextran, authentic FITC (10 micrograms/ml) was an effective labeling agent for vacuoles. The rapid kinetics (0.28 pmol/min per 10(6) cells at pH 5.5) and the pH dependence of FITC uptake suggest that the mechanism of FITC uptake involves diffusion rather than endocytosis. In view of these results, labeling experiments that use unpurified commercial FD should be interpreted with caution.

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Tricellulin Modulates Transport of Macromolecules in the Salivary Gland

Journal of Dental Research ◽

10.1177/0022034519896749 ◽

2019 ◽

Vol 99 (3) ◽

pp. 302-310 ◽

Cited By ~ 2

Author(s):

S.N. Min ◽

X. Cong ◽

Y. Zhang ◽

R.L. Xiang ◽

Y. Zhou ◽

...

Keyword(s):

Salivary Gland ◽

Tight Junction ◽

Tight Junctions ◽

Electrical Resistance ◽

Fluorescein Isothiocyanate ◽

Transepithelial Electrical Resistance ◽

Specific Expression ◽

Fluorescein Isothiocyanate Dextran ◽

Specific Expression Pattern ◽

Transport Of Macromolecules

Volume and composition of saliva are crucial for oral and systemic health. How substances, particularly macromolecules, are transported across the salivary gland epithelium has not been established in detail. Tricellulin is a component of tricellular tight junctions that form a central tube to serve as an important route for macromolecule transport. Whether tricellulin is expressed in the submandibular gland (SMG) and involved in salivation has been unknown. Here, by using Western blotting and immunofluorescence, tricellulin was found to be characteristically localized at tricellular contacts of human, rat, and mouse SMGs. Knockdown of tricellulin significantly increased, whereas overexpression of tricellulin decreased, paracellular permeability for 40-kDa but not for 4-kDa fluorescein isothiocyanate–dextran, while transepithelial electrical resistance was unaffected. Conversely, claudin-4 knockdown and overexpression affected transepithelial electrical resistance but not 40-kDa fluorescein isothiocyanate–dextran transport, suggesting that tricellulin regulated transport of macromolecules but not ions, which were mainly regulated by bicellular tight junctions (bTJs). Moreover, tricellulin was dynamically redistributed from tri- to bicellular membranes in cholinergically stimulated SMG tissues and cells. Immunoglobulin-like domain-containing receptor 1 (ILDR1) recruits tricellulin to tricellular contacts. The proportion of macromolecules in the saliva was increased, whereas the amount of stimulated saliva was unchanged in Ildr1-/- mice, which displayed abnormal tricellulin distribution in SMGs. Furthermore, tricellulin interacted with bTJ proteins, such as occludin, claudin-1, claudin-3, claudin-4, and ZO-1, in rat SMG epithelial polarized cell line SMG-C6. Knockdown of tricellulin decreased occludin levels. Thus, we revealed a specific expression pattern of tricellulin in SMG epithelium. Tricellulin not only functioned as a barrier for macromolecules but also modulated the connection of bTJs to the tight junction complex. Alterations in tricellulin expression and distribution could thereby change salivary composition. Our study provided novel insights on salivary gland tight junction organization and function.

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Low molecular weight heparin (nadroparin) improves placental permeability in rats with gestational diabetes mellitus via reduction of tight junction factors

Molecular Medicine Reports ◽

10.3892/mmr.2019.10868 ◽

2019 ◽

Cited By ~ 1

Author(s):

Yuehua Shi ◽

Jie Qian ◽

Feng Zhang ◽

Beibei Jia ◽

Xiaoyan Liu ◽

...

Keyword(s):

Diabetes Mellitus ◽

Molecular Weight ◽

Gestational Diabetes ◽

Gestational Diabetes Mellitus ◽

Tight Junction ◽

Low Molecular Weight Heparin ◽

Low Molecular Weight

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1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.18.5 ◽

2022 ◽

Vol 18 ◽

pp. 53-69

Author(s):

Ruan Carlos B Ribeiro ◽

Patricia G Ferreira ◽

Amanda de A Borges ◽

Luana da S M Forezi ◽

Fernando de Carvalho da Silva ◽

...

Keyword(s):

Molecular Weight ◽

Organic Synthesis ◽

Sulfonic Acid ◽

Pharmaceutical Market ◽

Low Molecular Weight ◽

Amino Groups ◽

Pharmacological Targets ◽

Secondary Amino ◽

Acid Salts

Several low molecular weight naphthoquinones are very useful in organic synthesis. These compounds have given rise to thousands of other naphthoquinones that have been tested against various microorganisms and pharmacological targets, including being used in the preparation of several drugs that are on the pharmaceutical market. Among these naphthoquinones, the series of compounds prepared from 1,2-naphthoquinone-4-sulfonic acid salts (β-NQS) stands out. In addition to being used in organic synthesis, they are excellent analytical derivatization reagents to spectrophotometrically determine drugs containing primary and secondary amino groups. This review summarizes the literature involving β-NQS.

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Copper treatment alters the permeability of tight junctions in cultured human intestinal Caco-2 cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1999.277.6.g1138 ◽

1999 ◽

Vol 277 (6) ◽

pp. G1138-G1148 ◽

Cited By ~ 10

Author(s):

Simonetta Ferruzza ◽

Maria-Laura Scarino ◽

Giuseppe Rotilio ◽

Maria Rosa Ciriolo ◽

Paolo Santaroni ◽

...

Keyword(s):

Tight Junction ◽

Tight Junctions ◽

Electrical Resistance ◽

Transepithelial Electrical Resistance ◽

Complete Medium ◽

Zonula Occludens ◽

Intracellular Effect ◽

Tight Junction Permeability ◽

Zonula Occludens 1 ◽

Effect Of Copper

The effects of copper on tight-junction permeability were investigated in human intestinal Caco-2 cells, monitoring transepithelial electrical resistance and transepithelial passage of mannitol. Apical treatment of Caco-2 cells with 10–100 μM CuCl2(up to 3 h) produced a time- and concentration-dependent increase in tight-junction permeability, reversible after 24 h in complete medium in the absence of added copper. These effects were not observed in cells treated with copper complexed to l-histidine [Cu(His)2]. The copper-induced increase in tight-junction permeability was affected by the pH of the apical medium, as was the apical uptake of64CuCl2, both exhibiting a maximum at pH 6.0. Treatment with CuCl2produced a concentration-dependent reduction in the staining of F actin but not of the junctional proteins zonula occludens-1, occludin, and E-cadherin and produced ultrastructural alterations to microvilli and tight junctions that were not observed after treatment with up to 200 μM Cu(His)2for 3 h. Overall, these data point to an intracellular effect of copper on tight junctions, mediated by perturbations of the F actin cytoskeleton.

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Production of ammonium by Helicobacter pylori mediates occludin processing and disruption of tight junctions in Caco-2 cells

Microbiology ◽

10.1099/mic.0.28049-0 ◽

2005 ◽

Vol 151 (10) ◽

pp. 3267-3276 ◽

Cited By ~ 34

Author(s):

Simon D. Lytton ◽

Wolfgang Fischer ◽

Wolfram Nagel ◽

Rainer Haas ◽

Franz X. Beck

Keyword(s):

Molecular Weight ◽

Helicobacter Pylori ◽

Tight Junction ◽

Tight Junctions ◽

Ammonium Salts ◽

Gastric Mucosal Damage ◽

Soluble Form ◽

Low Molecular Weight ◽

Partial Recovery ◽

H Pylori

Tight junctions, paracellular permeability barriers that define epithelial cell polarity, play an essential role in transepithelial transport, cell–cell adhesion and lymphocyte transmigration. They are also important for the maintenance of innate immune defence and intestinal antigen uptake. Ammonium () is elevated in the gastric aspirates of Helicobacter pylori-infected patients and has been implicated in the disruption of tight-junction functional integrity and the induction of gastric mucosal damage during H. pylori infection. The precise mechanism of the effect of ammonium and the molecular targets of ammonium in host tissue are not yet identified. To study the effects of ammonium on epithelial tight junctions, the human colon carcinoma cell line Caco-2 was cultured on permeable supports and the transepithelial resistance (TER) was measured at different time intervals following exposure to ammonium salts or H. pylori-derived ammonium. A biphasic response to treatment with ammonium was found. Acute exposure to ammonium salts or NH3/ derived from urea metabolism by wild-type H. pylori resulted in a 20–30 % decrease in TER. After 24 h, the NH4Cl-treated cells showed a partial recovery of TER. In contrast, the control culture, or cultures that were exposed to supernatants derived from urease-deficient H. pylori, showed no significant decrease in TER. Occludin-specific immunoblots revealed the expression of a low-molecular-weight form of occludin of 42 kDa upon NH3/ exposure. The results indicate that modulation of tight-junction function by H. pylori is ammonium-dependent and linked to the accumulation of a low-molecular-weight and detergent-soluble form of occludin.

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