Intercellular adhesion and formation of aggregates in normal and Talpid-3 mutant chick limb mesenchyme

1975 ◽  
Vol 18 (1) ◽  
pp. 97-111
Author(s):  
D.A. Ede ◽  
O.P. Flint
Keyword(s):  
Electron Micrographs ◽  
Large Cell ◽  
Cell Aggregates ◽  
Normal Cells ◽  
Cell Contacts ◽  
Cell Numbers ◽  
Limb Mesenchyme ◽  
Couette Viscometer ◽  
Mesenchyme Cells ◽  
Internal Architecture

It is demonstrated, using the Couette viscometer method, that talpid-3 mutant chick wing mesenchyme cells are more adhesive to one another than are normal cells. The relation of this to differences in the size and shape, and the internal architecture, of aggregates produced in rotation cultures of these cells was investigated. Sequences of sections through aggregates in all stages of formation, from 2-cell aggregates up to those with large cell numbers, were prepared. These confirm the theoretically predicted relationships among adhering cells which would produce the observed small, spherical talpid-3 aggregates and the larger, unevenly shaped normal aggregates. The cell contacts are further analysed with electron micrographs.

Experimental analysis of the control of expression of the homeobox-gene Msx-1 in the developing limb and face

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 41-48 ◽  
Author(s):  
J.M. Brown ◽  
S.E. Wedden ◽  
G.H. Millburn ◽  
L.G. Robson ◽  
R.E. Hill ◽  
...  
Keyword(s):  
Homeobox Gene ◽  
Host Tissue ◽  
Face To Face ◽  
Limb Mesenchyme ◽  
The Face ◽  
Mesenchyme Cells ◽  
Species Specific ◽  
Signalling Systems ◽  
Control Of Expression

Mouse mesenchyme was grafted into chick embryos to investigate the control of mesenchymal expression of Msx-1 in the developing limb and face. In situ hybridization, using species-specific probes, allows a comparison between Msx-1 expression in the graft and the host tissue. The results show that Msx-1 expression in both limb-to-limb and face-to-face grafts corresponds closely with the level of Msx-1 expression in the surrounding chick mesenchyme. Cells in grafts that end up within the host domain of Msx-1 express the gene irrespective of whether they were from normally expressing, or non-expressing, regions. Therefore Msx-1 expression in both the developing limb and the developing face appears to be position-dependent. Mesenchyme from each of the three major facial primordia behaved in the same way when grafted to the chick maxillary primordium. Reciprocal grafts between face and limb gave a different result: Msx-1 expression was activated when facial mesenchyme was grafted to the limb but not when limb mesenchyme was grafted to the face. This suggests either that there are quantitative or qualitative differences in two local signalling systems or that additional factors determine the responsiveness of the mesenchyme cells.

Growth and Differentiation of Human Stem Cell Factor/Erythropoietin-Dependent Erythroid Progenitor Cells In Vitro

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke
Keyword(s):  
Stem Cell ◽  
Progenitor Cells ◽  
Stem Cell Factor ◽  
Large Cell ◽  
Erythroid Cell ◽  
Erythroid Progenitors ◽  
Peripheral Blood Stem Cells ◽  
Erythroid Progenitor ◽  
Cell Numbers

Abstract Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

CD43 Interacts With Moesin and Ezrin and Regulates Its Redistribution to the Uropods of T Lymphocytes at the Cell-Cell Contacts

Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4632-4644 ◽  
Author(s):  
Juan M. Serrador ◽  
Marta Nieto ◽  
José L. Alonso-Lebrero ◽  
Miguel A. del Pozo ◽  
Javier Calvo ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Binding Proteins ◽  
Cell Aggregation ◽  
Actin Binding ◽  
Cell Aggregates ◽  
Actin Binding Proteins ◽  
Cell Contacts ◽  
T Lymphoblasts ◽  
Cell Cell

Abstract Chemokines as well as the signaling through the adhesion molecules intercellular adhesion molecule (ICAM)-3 and CD43 are able to induce in T lymphocytes their switching from a spherical to a polarized motile morphology, with the formation of a uropod at the rear of the cell. We investigated here the role of CD43 in the regulation of T-cell polarity, CD43-cytoskeletal interactions, and lymphocyte aggregation. Pro-activatory anti-CD43 monoclonal antibody (MoAb) induced polarization of T lymphocytes with redistribution of CD43 to the uropod and the CCR2 chemokine receptor to the leading edge of the cell. Immunofluorescence analysis showed that all three ezrin-radixin-moesin (ERM) actin-binding proteins localized in the uropod of both human T lymphoblasts stimulated with anti-CD43 MoAb and tumor-infiltrating T lymphocytes. Radixin localized at the uropod neck, whereas ezrin and moesin colocalized with CD43 in the uropod. Biochemical analyses showed that ezrin and moesin coimmunoprecipitated with CD43 in T lymphoblasts. Furthermore, in these cells, the CD43-associated moesin increased after stimulation through CD43. The interaction of moesin and ezrin with CD43 was specifically mediated by the cytoplasmic domain of CD43, as shown by precipitation of both ERM proteins with a GST-fusion protein containing the CD43 cytoplasmic tail. Videomicroscopy analysis of homotypic cell aggregation induced through CD43 showed that cellular uropods mediate cell-cell contacts and lymphocyte recruitment. Immunofluorescence microscopy performed in parallel showed that uropods enriched in CD43 and moesin localized at the cell-cell contact areas of cell aggregates. The polarization and homotypic cell aggregation induced through CD43 was prevented by butanedione monoxime, indicating the involvement of myosin cytoskeleton in these phenomena. Altogether, these data indicate that CD43 plays an important regulatory role in remodeling T-cell morphology, likely through its interaction with actin-binding proteins ezrin and moesin. In addition, the redistribution of CD43 to the uropod region of migrating lymphocytes and during the formation of cell aggregates together with the enhancing effect of anti-CD43 antibodies on lymphocyte cell recruitment suggest that CD43 plays a key role in the regulation of cell-cell interactions during lymphocyte traffic.

Filamentous forms of Streptococcus cremoris and Streptococcus lactis. Observations on structure and susceptibility to lysis

1971 ◽  
Vol 17 (7) ◽  
pp. 897-902 ◽  
Author(s):  
I. J. McDonald
Keyword(s):  
Electron Micrographs ◽  
Cell Walls ◽  
Normal Cell ◽  
Filament Formation ◽  
Normal Cells ◽  
Base Content ◽  
Daughter Cells ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Dna Base

Filamentous cultures of Streptococcus cremoris and Streptococcus lactis were isolated from growth which formed in orifices of medium inlet tubes of chemostats. Filamentous variants were maintained by biweekly transfer in agar stab cultures. Bacteria from parent and filamentous cultures grown in broth had the same DNA base content and the same bacteriophage susceptibility. Electron micrographs showed that filamentous streptococci had apparently normal cell walls and slightly enlarged cross walls. Filaments appeared to result from failure of daughter cells to separate after division. Filamentous cells were less readily autolyzed and were less susceptible to lysis by Iysozyme than normal cells. The results suggest that filament formation in lactic streptococci was associated with lower autolysin activity.

scholarly journals Flow Cytometric Analysis of Adherence of Porphyromonas gingivalis to Oral Epithelial Cells

2007 ◽  
Vol 75 (5) ◽  
pp. 2484-2492 ◽  
Author(s):  
Rishi D. Pathirana ◽  
Neil M. O'Brien-Simpson ◽  
Kumar Visvanathan ◽  
John A. Hamilton ◽  
Eric C. Reynolds
Keyword(s):  
Porphyromonas Gingivalis ◽  
Competitive Inhibition ◽  
Flow Cytometric Analysis ◽  
Large Cell ◽  
Cell Aggregates ◽  
Bacterial Cells ◽  
Kb Cells ◽  
Flow Cytometric ◽  
Logarithmic Relationship ◽  
Oral Epithelial

ABSTRACT By using fluorescence microscopy, fluorescently labeled Porphyromonas gingivalis W50 was shown to adhere to oral epithelial (KB) cells as discrete cells or small cell aggregates, whereas P. gingivalis ATCC 33277 bound as large cell aggregates. Flow cytometric analysis showed that for P. gingivalis W50 there was a logarithmic relationship between the bacterial cell ratio (BCR), that is the number of bacterial cells to KB cells, and the percentage of KB cells with W50 cells attached. This percentage of KB cells with W50 attached reached a plateau of ∼84% cells at a BCR of 500:1. In contrast, a quadratic relationship was observed between BCR and the percentage of KB cells with P. gingivalis ATCC 33277 attached, reaching a maximum of 47% at a BCR of 100:1 but decreasing to 7% at a BCR of 1,000:1. The lower binding of ATCC 33277 at high cell concentrations was attributed to autoaggregation. P. gingivalis W50 cells treated with an inhibitor (Nα-p-tosyl-l-lysine chloromethyl ketone [TLCK]) of its RgpA-Kgp proteinase-adhesin complex exhibited significantly reduced binding to KB cells than to untreated cells, suggesting a role for proteinase activity in binding to KB cells. Competitive inhibition with purified proteinase-active and TLCK-inactivated RgpA-Kgp complex significantly decreased the adherence of P. gingivalis W50 cells to KB cells. Furthermore, isogenic mutants of P. gingivalis W50 lacking the kgp gene product, but not the rgpA or rgpB gene products, exhibited significantly decreased adherence to KB cells compared to the wild type.

scholarly journals Tbx4 function during hindlimb development reveals a novel mechanism to explain the origins of proximal limb defects

Development ◽  
2021 ◽  
Author(s):  
Veronique Duboc ◽  
Fatima Sulaiman ◽  
Eleanor Feneck ◽  
Anna Kucharska ◽  
Donald Bell ◽  
...  
Keyword(s):  
Image Analysis ◽  
Transcription Factors ◽  
Gene Regulatory Network ◽  
Regulatory Network ◽  
Micromass Culture ◽  
Limb Defects ◽  
Limb Mesenchyme ◽  
Gene Regulatory ◽  
Live Image ◽  
Mesenchyme Cells

We dissect genetically a gene regulatory network, including the transcription factors Tbx4, Pitx1 and Isl1 that act cooperatively to establish the hindlimb bud and identify key differences in the pathways that initiate formation of the hindlimb and forelimb. Using live image analysis of limb mesenchyme cells undergoing chondrogenesis in micromass culture, we distinguish a series of changes in cellular behaviours and cohesiveness that are required for chondrogenic precursors to undergo differentiation. Furthermore, we provide evidence that the proximal hindlimb defects in the Tbx4 mutant result from a failure in the early differentiation step of chondroprogenitors into chondrocytes, providing a novel explanation for the origins of proximally-biased limb defects.

scholarly journals Murine xenograft bioreactors for human immunopeptidome discovery

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
James M. Heather ◽  
Paisley T. Myers ◽  
Feng Shi ◽  
Mohammad Ovais Aziz-Zanjani ◽  
Keira E. Mahoney ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Cultured Cells ◽  
Large Cell ◽  
Binding Affinities ◽  
Binding Motifs ◽  
Immunodeficient Mice ◽  
Cell Numbers ◽  
Hla Binding

AbstractThe study of peptides presented by MHC class I and class II molecules is limited by the need for relatively large cell numbers, especially when studying post-translationally modified or otherwise rare peptide species. To overcome this problem, we pose the hypothesis that human cells grown as xenografts in immunodeficient mice should produce equivalent immunopeptidomes as cultured cells. Comparing human cell lines grown either in vitro or as murine xenografts, we show that the immunopeptidome is substantially preserved. Numerous features are shared across both sample types, including peptides and proteins featured, length distributions, and HLA-binding motifs. Peptides well-represented in both groups were from more abundant proteins, or those with stronger predicted HLA binding affinities. Samples grown in vivo also recapitulated a similar phospho-immunopeptidome, with common sequences being those found at high copy number on the cell surface. These data indicate that xenografts are indeed a viable methodology for the production of cells for immunopeptidomic discovery.

Analysis of skin fibroblast aggregation in Duchenne muscular dystrophy

1981 ◽  
Vol 48 (1) ◽  
pp. 291-300
Author(s):  
G.E. Jones ◽  
J.A. Witkowski
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Pattern Formation ◽  
Normal Cell ◽  
Skin Fibroblast ◽  
Single Cells ◽  
Size Analysis ◽  
Normal Cells ◽  
Couette Viscometer ◽  
Intermediate Size

Skin fibroblasts from patients with Duchenne muscular dystrophy have a low intercellular adhesiveness compared with normal cells when aggregated in a Couette viscometer (collision efficiencies of 2.52 and 4.62, respectively). The pattern of aggregation was quantitated using a digitizer system to measure the areas of particles (single cells and aggregates) formed after 20 min aggregation. This size analysis showed that the majority of dystrophic cells remained unaggregated but that a small number of very large aggregates was always formed. Normal cell suspensions only rarely contained large aggregates but contained many intermediate-size aggregates. These differences in intercellular adhesiveness and aggregate pattern formation indicate that there may be an alteration in the surface of dystrophic cells.

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