Vitelline Membrane Outer Layer 1 Homolog Interacts With Lysozyme C and Promotes the Stabilization of Tear Film

2014 ◽  
Vol 55 (10) ◽  
pp. 6722-6727 ◽  
Author(s):  
Z. Wang ◽  
Z. Chen ◽  
Q. Yang ◽  
Y. Jiang ◽  
L. Lin ◽  
...  
Keyword(s):  
Outer Layer ◽  
Tear Film ◽  
Vitelline Membrane ◽  
Lysozyme C

Memoirs: The Development of the Mole (Talpa Europea), the Ovarian Ovum, and Segmentation of the Ovum

1886 ◽  
Vol s2-26 (102) ◽  
pp. 157-174
Author(s):  
WALTER HEAPE
Keyword(s):  
Fallopian Tube ◽  
Outer Layer ◽  
Variable Number ◽  
The Other ◽  
Vitelline Membrane ◽  
Follicular Cells ◽  
Zona Radiata ◽  
Polar Bodies ◽  
Nucleolar Material ◽  
Female Pronucleus

The membranes surrounding the ripe ovarian, ovum are two: (1) a single outer, thick, zona radiata, with a granular peripheral and a transparent inner portion, pierced radially by fine canals through which nutriment is obtained by the ovum from, the follicular cells (of the discus proligerus) immediately in contact with the zona: (2) an inner very delicate vitelline membrane which closely covers the ovum itself; and between these membranes is a space, the circum-vitelline space. The confirmation of Reichert's (No. 18), Meyer's (No. 17), and van Beneden's (No. 4) observations as to the presence of the inner delicate vitelline membrane appears of some interest as many embryologists are still sceptical of its existence, while the relation of the follicular cells with the radial canals of the zona supports the view as to the source of the nutriment of the ovarian ovum. On the other hand the fact that nothing was seen comparable to a micropyle in the zona, such as M. Barry (No. 3), and Meissner (No. 16), described, nor any follicular cells within the zona such as Lindgren (No. 15), von Sehlen (No. 21), and Virchow (No. 22), have observed, is some further proof that the conditions of the material investigated by these authors was abnormal. The yolk contained within the ovum, which is of two kinds: viz. (1) homogeneous vesicular bodies, (2) minute highly refractile granules, is contained within the meshes of a protoplasmic reticulum; it is dense and contains no large globules such as Beneden (Nos. 6 and 7) describes in theBat's ova. The rounded or oval nucleus contains a single centrally placed nucleolus and a variable number of smaller or larger granules, which may possibly be considered as nucleolar material. During maturation the vitellus becomes divided into a medullary granular, and a cortical non-granular portion, the circum-vitelline space between the zona radiata and the vitelline membrane is enlarged, while the vitellus itself contracts away from the vitelline membrane excepting (1) here and there where pseudopodia-like processes connect the two, and (2) at one spot where the polar bodies are formed. At this latter place two polar bodies may be seen in the specimen figured, outside the vitelline membrane, whilst the nucleus remains as the female pronucleus lying in the peripheral portion of the ovum. Finally, the vitellus again expands and the nucleus retires to the centre of the ovum and is no longer to be seen. Assuming that these observations are correct, Beneden's description of the ejection of the vesicle to form the polar bodies and the subsequent non-nucleated condition of the ovum must be considered erroneous. Impregnation appears to be effected by a single spermatazoon, although a considerable number of spermatazoa find their way through the zona and may be seen lying passively in the circumvitelline space. The segmentation occurs while the ovum travels down the Fallopian tube. Two and then four segments are formed, after which the course of segmentation is irregular. The segments themselves are of irregular size and do not appear to be divisible into two kinds (epiblastic and hypoblastic) as Beneden describes. After its entrance into the uterus, a division of the segments into an outer hyaline layer and inner deeply granular mass takes place, and I would suggest the hypothesis that the vitelline matter which was originally contained in all segments alike has been transmitted from the outer segments to the segments lying in the interior of the ovum, in order that the former segments may the more readily and actively multiply and flatten out to form the wall of the blastodermic vesicle. The epiblast of the vesicle and of the embryo is derived from the whole of the outer layer and by far the largest proportion of the inner mass of segments. The hypoblast is derived from the small remaining portion of the inner mass and the mesablast, subsequently, from both epiblast and hypoblast layers. This being the case, the division of the segmentation spheres, by Beneden, into epiblast and hypoblast spheres from the time when the first two segments were formed, is incorrect; and at the same time the theory of a comparison of the metagastrula stage with the gastrula of other animals is likewise untenable.

Characterization of Vitelline Membrane Outer Layer Protein I, VMO-I: Amino Acid Sequence and Structural Stability1

1995 ◽  
Vol 117 (6) ◽  
pp. 1183-1191 ◽  
Author(s):  
Shoko Kido ◽  
Yukio Doi ◽  
Fimi Kim ◽  
Emi Morishita ◽  
Hiroshi Narita ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Outer Layer ◽  
Vitelline Membrane

The Lipid Layer: The Outer Surface of the Ocular Surface Tear Film

2001 ◽  
Vol 21 (4) ◽  
pp. 407-418 ◽  
Author(s):  
James P. McCulley ◽  
Ward E. Shine
Keyword(s):  
Water Vapor ◽  
Fatty Acid ◽  
Outer Surface ◽  
Outer Layer ◽  
Tear Film ◽  
Polar Phase ◽  
Lipid Layer ◽  
Water Vapor Transmission ◽  
Aqueous Layer ◽  
Alcohol Composition

The outer layer of the tear film—the lipid layer—has numerous functions. It is a composite monolayer composed of a polar phase with surfactant properties and a nonpolar phase. In order to achieve an effective lipid layer, the nonpolar phase, which retards water vapor transmission, is dependent on a properly structured polar phase. Additionally, this composite lipid layer must maintain its integrity during a blink. The phases of the lipid layer depend on both lipid type as well as fatty acid and alcohol composition for functionality. Surprisingly, the importance of the composition of the aqueous layer of the tear film in proper structuring of the lipid layer has not been recognized. Finally, lipid layer abnormalities and their relationship to ocular disease are beginning to be clarified.

scholarly journals Downregulation of Extraembryonic Tension Controls Body Axis Formation in Avian Embryos

2021 ◽  
Author(s):  
Daniele Kunz ◽  
Anfu Wang ◽  
Chon U Chan ◽  
Robyn H. Pritchard ◽  
Wenyu Wang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Outer Layer ◽  
Shape Change ◽  
Body Axis ◽  
Vitelline Membrane ◽  
Axis Formation ◽  
Extraembryonic Tissue ◽  
Avian Embryos ◽  
Embryonic Tissues ◽  
Tissue Tension

AbstractEmbryonic tissues undergoing shape change draw mechanical input from extraembryonic substrates. In avian eggs, the early blastoderm disk is under the tension of the vitelline membrane (VM). Here we report that chicken VM characteristically downregulates tension and stiffness to facilitate stage-specific embryo morphogenesis. While early relaxation of the VM impairs blastoderm expansion, maintaining VM tension in later stages resists the convergence of the posterior body causing stalled elongation, open neural tube, and axis rupture. Biochemical and structural analysis shows that VM weakening follows the reduction of its outer-layer glycoprotein fibers, which is caused by an increasing albumen pH due to CO2 release from the egg. Our results identify a previously unrecognized mechanism of body axis defects through mis-regulation of extraembryonic tissue tension.

Isolation, characterization and localization of a lectin within the vitelline membrane of the hen's egg

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 389-407
Author(s):  
Geoffrey M. W. Cook ◽  
Ruth Bellairs ◽  
Nicholas G. Rutherford ◽  
Caroline A. Stafford ◽  
Thomas Alderson
Keyword(s):  
Outer Layer ◽  
Gel Electrophoresis ◽  
Immunofluorescence Microscopy ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Vitelline Membrane ◽  
Two Dimensional Gel Electrophoresis ◽  
Sulphated Polysaccharides ◽  
Hen’S Egg ◽  
Bactericidal Properties

A lectin with an affinity for certain sulphated polysaccharides, such as fucoidin and dextran sulphate, has been isolated from the vitelline membrane of hens' eggs and purified to homogeneity as assessed by two-dimensional gel electrophoresis. Polyclonal and monoclonal antibodies have been raised to the lectin and used in indirect immunofluorescence microscopy to localize the agglutinin in the outer layer of the vitelline membrane, where the lectin persists prior to the breakdown of the vitelline membrane. The quantity of lectin extracted from the two layers of the membrane, which have been separated by the method of Bellairs, Harkness & Harkness (1963), correlated well with the results of immunofluorescence microscopy. Sodium dodecyl sulphate—polyacrylamide gel electrophoresis of the two layers of the membrane indicates that each layer has a distinctive polypeptide composition, the outer layer containing in particular lysozyme and avidin. The evidence obtained in this study indicates that the lectin is not involved in adhesion of the blastoderm to the vitelline membrane; neither is it involved in the expansion of the blastoderm nor in maintaining the strength of the membrane. The possible roles in promoting transport of solutes across the membrane as well as providing bactericidal properties to the egg are discussed.

scholarly journals Observations on the Development and Struoture of the Vitelline Membrane of the Hen's Egg: An Eleotron Miorosoope Study

1969 ◽  
Vol 22 (3) ◽  
pp. 653 ◽  
Author(s):  
Joan M Bain ◽  
Janice M Hall
Keyword(s):  
Outer Layer ◽  
Egg Yolk ◽  
Vitelline Membrane ◽  
Secretory Cells ◽  
White Leghorn ◽  
Hen’S Egg ◽  
The Relationship

Stages in the development of the outer layer of the vitelline membrane of a hen's egg have been observed in an egg found in the infundibulum of a sacrificed White Leghorn hen. Tissue from the infundibulum and the underlying egg yolk material was taken at increasing distances from the upper end of the egg and the relationship between the secretory cells of the infundibulum and the vitelline mem-brane observed. The structure of the vitelline membrane in ova just liberated from the ovary and not yet in the oviduct and that of the vitelline membrane in new-laid eggs from other White Leghorn hens were observed for comparison.

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