Adhesion of Lactobacillus acidophilus to avian intestinal epithelial cells mediated by the crystalline bacterial cell surface layer (S-layer)

1993 ◽  
Vol 74 (3) ◽  
pp. 290-294 ◽  
Author(s):  
C. Schneitz ◽  
L. Nuotio ◽  
K. Lounatma
1995 ◽  
Vol 108 (1) ◽  
pp. 369-377 ◽  
Author(s):  
K.L. Soole ◽  
M.A. Jepson ◽  
G.P. Hazlewood ◽  
H.J. Gilbert ◽  
B.H. Hirst

To evaluate whether a glycosylphosphatidylinositol (GPI) anchor can function as a protein sorting signal in polarized intestinal epithelial cells, the GPI-attachment sequence from Thy-1 was fused to bacterial endoglucanase E' (EGE') from Clostridium thermocellum and polarity of secretion of the chimeric EGE'-GPI protein was evaluated. The chimeric EGE'-GPI protein was shown to be associated with a GPI anchor by TX-114 phase-partitioning and susceptibility to phosphoinositol-specific phospholipase C. In polarized MDCK cells, EGE' was localized almost exclusively to the apical cell surface, while in polarized intestinal Caco-2 cells, although 80% of the extracellular form of the enzyme was routed through the apical membrane over a 24 hour period, EGE' was also detected at the basolateral membrane. Rates of delivery of EGE'-GPI to the two membrane domains in Caco-2 cells, as determined with a biotinylation protocol, revealed apical delivery was approximately 2.5 times that of basolateral. EGE' delivered to the basolateral cell surface was transcytosed to the apical surface. These data indicate that a GPI anchor does represent a dominant apical sorting signal in intestinal epithelial cells. However, the mis-sorting of a proportion of EGE'GPI to the basolateral surface of Caco-2 cells provides an explanation for additional sorting signals in the ectodomain of some endogenous GPI-anchored proteins.


1982 ◽  
Vol 201 (2) ◽  
pp. 359-366 ◽  
Author(s):  
Wlodzimierz Sasak ◽  
Annette Herscovics ◽  
Andrea Quaroni

We studied mannose-containing glycopeptides and glycoproteins of subconfluent and confluent intestinal epithelial cells in culture. Cells were labelled with d-[2-3H]mannose for 24h and treated with Pronase or trypsin to release cell-surface components. The cell-surface and cell-residue fractions were then exhaustively digested with Pronase and the resulting glycopeptides were fractionated on Bio-Gel P-6, before and after treatment with endo-β-N-acetylglucosaminidase H to distinguish between high-mannose and complex oligosaccharides. The cell-surface glycopeptides were enriched in complex oligosaccharides as compared with residue glycopeptides, which contained predominantly high-mannose oligosaccharides. Cell-surface glycopeptides of confluent cells contained a much higher proportion of complex oligosaccharides than did glycopeptides from subconfluent cells. The ability of the cells to bind [3H]concanavalin A decreased linearly with increasing cell density up to 5 days in culture and then remained constant. When growth of the cells was completely inhibited by either retinoic acid or cortisol, no significant difference was observed in the ratio of complex to high-mannose oligosaccharides in the cell-surface glycopeptides of subconfluent cells. Only minor differences were found in total mannose-labelled glycoproteins between subconfluent and confluent cells by two-dimensional gel analysis. The adhesion of the cells to the substratum was measured at different stages of growth and cell density. Subconfluent cells displayed a relatively weak adhesion, which markedly increased with increased cell density up to 6 days in culture. It is suggested that alterations in the structure of the carbohydrates of the cell-surface glycoproteins are dependent on cell density rather than on cell growth. These changes in the glycopeptides are correlated with the changes in adhesion of the cells to the substratum.


2021 ◽  
Vol 12 ◽  
Author(s):  
Joshua Oluoch Amimo ◽  
Sergei Alekseevich Raev ◽  
Juliet Chepngeno ◽  
Alfred Omwando Mainga ◽  
Yusheng Guo ◽  
...  

Rotavirus (RV) is the foremost enteric pathogen associated with severe diarrheal illness in young children (<5years) and animals worldwide. RV primarily infects mature enterocytes in the intestinal epithelium causing villus atrophy, enhanced epithelial cell turnover and apoptosis. Intestinal epithelial cells (IECs) being the first physical barrier against RV infection employs a range of innate immune strategies to counteract RVs invasion, including mucus production, toll-like receptor signaling and cytokine/chemokine production. Conversely, RVs have evolved numerous mechanisms to escape/subvert host immunity, seizing translation machinery of the host for effective replication and transmission. RV cell entry process involve penetration through the outer mucus layer, interaction with cell surface molecules and intestinal microbiota before reaching the IECs. For successful cell attachment and entry, RVs use sialic acid, histo-blood group antigens, heat shock cognate protein 70 and cell-surface integrins as attachment factors and/or (co)-receptors. In this review, a comprehensive summary of the existing knowledge of mechanisms underlying RV-IECs interactions, including the role of gut microbiota, during RV infection is presented. Understanding these mechanisms is imperative for developing efficacious strategies to control RV infections, including development of antiviral therapies and vaccines that target specific immune system antagonists within IECs.


1983 ◽  
Vol 211 (1) ◽  
pp. 75-80 ◽  
Author(s):  
W Sasak ◽  
A Quaroni ◽  
A Herscovics

Confluent cultured intestinal epithelial cells displayed greater adhesion to the substratum than did subconfluent cells. Subconfluent and confluent cells were labelled with [3H]fucose for 24h and the cell-surface components were released by mild Pronase treatment. After extensive Pronase digestion, cell-surface and cell-residue glycopeptides were fractionated on Bio-Gel P-6. The cell surface contained a higher proportion of lower-molecular-weight glycopeptides than the residue. No significant difference in elution pattern was found between total cell-surface glycopeptides of subconfluent and confluent cells. However, confluent cells contained almost twice as much [3H]-fucose-labelled glycopeptides that were bound to concanavalin A-Sepharose and were subsequently eluted with 20mM-methyl alpha-D-glucopyranoside as subconfluent cells. When the bound glycopeptides were chromatographed on Bio-Gel P-6, it was found that confluent cells contained a larger proportion of lower-molecular-weight glycopeptides than subconfluent cells. This difference in size was eliminated after treatment of glycopeptides with sialidase. When growth of subconfluent cells was inhibited with a non-toxic concentration of retinoic acid, no significant effect on the elution pattern of [3H]fucose-labelled glycopeptides was observed on either Bio-Gel P-6 or concanavalin A-Sepharose. No significant difference was found in the total [3H]fucose-labelled glycoproteins from subconfluent and confluent cells by two-dimensional gel electrophoresis. It is suggested that the differences in [3H]fucose-labelled glycopeptides between subconfluent and confluent cells are cell-density-dependent rather than growth-dependent, and that these differences are likely to result from some changes in glycosylation mechanism(s). Furthermore, the differences in cell-surface glycopeptides may be related to the changes in the adhesion of the cells to the substratum.


mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Chonsaeng Kim ◽  
Jeffrey M. Bergelson

ABSTRACTEnteroviruses invade the host by crossing the intestinal mucosa, which is lined by polarized epithelium. A number of enteroviruses, including echoviruses (EV) and group B coxsackieviruses (CVB), initiate infection by attaching to decay-accelerating factor (DAF), a molecule that is highly expressed on the apical surface of polarized epithelial cells. We previously observed that entry of DAF-binding CVB3 into polarized intestinal epithelial cells occurs by an unusual endocytic mechanism that requires caveolin but does not involve clathrin or dynamin. Here we examined the entry of a DAF-binding echovirus, EV7. We found that drugs, small interfering RNAs (siRNAs), and dominant negative mutants that target factors required for clathrin-mediated endocytosis, including clathrin and dynamin, inhibited both EV7 infection and internalization of virions from the cell surface. Once virus had entered the cell, it colocalized with markers of early endosomes (EEA1) and then late endosomes (LAMP-2). Inhibition of endosomal maturation—with siRNAs or dominant negative mutants targeting Rab5 and Rab7—inhibited infection and prevented release of viral RNA into the cell. These results indicate that EV7 is internalized by clathrin-mediated endocytosis and then moves to early and late endosomes before releasing its RNA. Trafficking through endosomes is known to be important for viruses that depend on low pH or endosomal cathepsin proteases to complete the entry process. However, we found that EV7 infection required neither low pH nor cathepsins.IMPORTANCEThe results demonstrate that echovirus 7 (EV7), after binding to decay-accelerating factor (DAF) on the cell surface, enters cells by clathrin-mediated endocytosis; this entry mechanism differs markedly from that of another DAF-binding enterovirus, coxsackievirus B3 (CVB3). Thus, after attachment to the same cell surface receptor, these closely related viruses enter the same cells by different mechanisms. The cellular cues required for release of viral RNA from the enterovirus capsid (“uncoating”) remain poorly defined. We found that EV7 moved to late endosomes and that release of RNA depended on endosomal maturation; nonetheless, EV7 did not depend on the endosomal factors implicated in uncoating and entry by other viruses. The results suggest either that an unidentified endosomal factor is essential for uncoating of EV7 or that trafficking through the endosome is an essential step in a pathway that leads to another intracellular organelle where uncoating is completed.


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