Monensin inhibits secretion of extracellular matrix and the spreading of mesoderm cells in the early chick embryo. 1987

E J Sanders, and P Chokka
Department of Physiology, University of Alberta, Edmonton, Canada.

Chick embryos in culture were treated with the secretion-inhibiting ionophore monensin at the gastrulation stage of development. After treatment for 5 h at a concentration of 10(-5) M the embryos showed a drastic reduction in the tissue space between the upper and lower epithelia, and reduced spreading of the mesoderm cells that occupied this space. The basement membrane, to which many mesoderm cells are normally attached, showed varying degrees of disruption, which permitted blebbing of the overlying epithelium. Intracellularly, the treatment caused extensive vacuolization in all tissues. These results were consistent with the effects expected by removal of hyaluronic acid from the extracellular space, and this was confirmed by demonstrating a sharp reduction in glucosamine incorporation in this region. Examination of the effects of monensin on isolated mesoderm cells in culture using interference reflection microscopy indicated that the spreading of these cells was reduced independently of the changes in the extracellular matrix of the embryo. That this was probably due to the inhibition of cell surface fibronectin secretion was shown by demonstrating severe changes in the distribution of this glycoprotein using the immunofluorescent technique. It is concluded that the effects of monensin on this intact, developing system are due primarily to the disruption of hyaluronic acid secretion, but that disrupted fibronectin synthesis contributes to the reduced spreading of mesoderm cells.

UI MeSH Term Description Entries
D008648 Mesoderm The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube. Mesenchyme,Dorsal Mesoderm,Intermediate Mesoderm,Lateral Plate Mesoderm,Mesenchyma,Paraxial Mesoderm,Dorsal Mesoderms,Intermediate Mesoderms,Lateral Plate Mesoderms,Mesenchymas,Mesoderm, Dorsal,Mesoderm, Intermediate,Mesoderm, Lateral Plate,Mesoderm, Paraxial,Mesoderms, Dorsal,Mesoderms, Intermediate,Mesoderms, Lateral Plate,Mesoderms, Paraxial,Paraxial Mesoderms,Plate Mesoderm, Lateral,Plate Mesoderms, Lateral
D008854 Microscopy, Electron Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen. Electron Microscopy
D008985 Monensin An antiprotozoal agent produced by Streptomyces cinnamonensis. It exerts its effect during the development of first-generation trophozoites into first-generation schizonts within the intestinal epithelial cells. It does not interfere with hosts' development of acquired immunity to the majority of coccidial species. Monensin is a sodium and proton selective ionophore and is widely used as such in biochemical studies. Coban,Monensin Monosodium Salt,Monensin Sodium,Monensin-A-Sodium Complex,Rumensin,Monensin A Sodium Complex
D009924 Organ Culture Techniques A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1) Organ Culture,Culture Technique, Organ,Culture Techniques, Organ,Organ Culture Technique,Organ Cultures
D002448 Cell Adhesion Adherence of cells to surfaces or to other cells. Adhesion, Cell,Adhesions, Cell,Cell Adhesions
D002465 Cell Movement The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell. Cell Migration,Locomotion, Cell,Migration, Cell,Motility, Cell,Movement, Cell,Cell Locomotion,Cell Motility,Cell Movements,Movements, Cell
D002642 Chick Embryo The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching. Embryo, Chick,Chick Embryos,Embryos, Chick
D005109 Extracellular Matrix A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. Matrix, Extracellular,Extracellular Matrices,Matrices, Extracellular
D005353 Fibronectins Glycoproteins found on the surfaces of cells, particularly in fibrillar structures. The proteins are lost or reduced when these cells undergo viral or chemical transformation. They are highly susceptible to proteolysis and are substrates for activated blood coagulation factor VIII. The forms present in plasma are called cold-insoluble globulins. Cold-Insoluble Globulins,LETS Proteins,Fibronectin,Opsonic Glycoprotein,Opsonic alpha(2)SB Glycoprotein,alpha 2-Surface Binding Glycoprotein,Cold Insoluble Globulins,Globulins, Cold-Insoluble,Glycoprotein, Opsonic,Proteins, LETS,alpha 2 Surface Binding Glycoprotein
D005455 Fluorescent Antibody Technique Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy. Antinuclear Antibody Test, Fluorescent,Coon's Technique,Fluorescent Antinuclear Antibody Test,Fluorescent Protein Tracing,Immunofluorescence Technique,Coon's Technic,Fluorescent Antibody Technic,Immunofluorescence,Immunofluorescence Technic,Antibody Technic, Fluorescent,Antibody Technics, Fluorescent,Antibody Technique, Fluorescent,Antibody Techniques, Fluorescent,Coon Technic,Coon Technique,Coons Technic,Coons Technique,Fluorescent Antibody Technics,Fluorescent Antibody Techniques,Fluorescent Protein Tracings,Immunofluorescence Technics,Immunofluorescence Techniques,Protein Tracing, Fluorescent,Protein Tracings, Fluorescent,Technic, Coon's,Technic, Fluorescent Antibody,Technic, Immunofluorescence,Technics, Fluorescent Antibody,Technics, Immunofluorescence,Technique, Coon's,Technique, Fluorescent Antibody,Technique, Immunofluorescence,Techniques, Fluorescent Antibody,Techniques, Immunofluorescence,Tracing, Fluorescent Protein,Tracings, Fluorescent Protein

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