Surface coat material associated with the cells of the developing lens vesicle in the chick embryo

1981 ◽  
Vol 201 (2) ◽  
pp. 261-271 ◽  
Author(s):  
John J. Van Rybroek ◽  
Mark D. Olson
Keyword(s):  
Chick Embryo ◽  
Surface Coat ◽  
Lens Vesicle ◽  
Coat Material

A STUDY OF THE INHIBITORY EFFECTS OF CHICK WHOLE EYE EXTRACT ON THE DEVELOPMENT OF THE LENS OF THE CHICK EMBRYO IN VITRO

1966 ◽  
Vol 44 (4) ◽  
pp. 661-676 ◽  
Author(s):  
Robert P. Thompson
Keyword(s):  
Chick Embryo ◽  
Nutrient Medium ◽  
Inhibitory Effect ◽  
Reactive System ◽  
Vesicle Formation ◽  
Inhibitory Effects ◽  
Muscle Extract ◽  
Lens Vesicle ◽  
And Control

To demonstrate the phenomenon of homologous inhibition by clearly interpretable results in a readily reactive system, experiments were carried out to study the effect of chick whole eye extract on the development of the vesicular lens of the chick embryo in vitro. The heads of embryos of 11 through 13 somites were explanted onto nutrient medium diluted with varying amounts of the extract, and cultured for 30 hours. A total of 35 embryos exposed to concentrations of 1:1, 1:2, and 1:4 (extract to medium) showed complete inhibition of lens vesicle formation. Of a total of 53 embryos on concentrations of 1:8, 1:16, 1:32, and 1:64, more than 50% showed inhibition of vesicle formation. The inhibitory effect disappeared at a concentration of 1:128. Control material exposed to some equivalent concentrations of nutrient medium – saline mixtures showed inhibition of vesicle formation in only 15% of 33 embryos. Of a total of 27 control embryos exposed to ventricular muscle extract, approximately one-third showed inhibition of vesicle formation at concentrations of 1:8 and 1:16, with the inhibitory effect disappearing at 1:32. The implications of this result are discussed. Other factors and control experiments are described and their value is assessed.

The surface coat of infective larvae of Trichinella spiralis

Parasitology ◽  
1999 ◽  
Vol 118 (5) ◽  
pp. 509-522 ◽  
Author(s):  
J. MODHA ◽  
M. C. ROBERTS ◽  
W. M. ROBERTSON ◽  
G. SWEETMAN ◽  
K. A. POWELL ◽  
...  
Keyword(s):  
Trichinella Spiralis ◽  
Amorphous Material ◽  
Protein S ◽  
Datura Stramonium ◽  
Metabolic Energy ◽  
Surface Coat ◽  
Microscopical Examination ◽  
Infective Larvae ◽  
Coat Material ◽  
Pronase Treatment

The surface coat of the infective larvae of the parasitic nematode Trichinella spiralis was characterized with respect to its biophysical properties, morphology and composition. Labelling of larvae with the fluorescent surface probe PKH26 was lost after activation (by incubation in mammalian medium containing trypsin and bile), or following pronase treatment. Electron microscopical examination revealed that pronase treatment resulted in the loss of an amorphous surface layer only, further demonstrating the specificity of PKH26 for the larval surface coat. Surface coat shedding was inhibited by sodium azide and carbonyl cyanide, or by incubation of larvae at 4°C, suggesting the shedding process required metabolic energy. Pre-labelled, unactivated larvae demonstrated continuous slow surface coat shedding and could be re-labelled with PKH26, indicating that the shed coat is replaced in these parasites. However, pre-labelled larvae which were activated failed to re-label with the probe, suggesting that activation provides an irreversible trigger for surface changes. PKH26, therefore, is a useful marker for larval activation. Examination of the shed coat material by scanning electron microscopy revealed 2 types of morphologies; one comprising thin multilaminate sheets and the other of amorphous material with ridges producing a fingerprint-like motif. Western- and lectin-blotting of the shed coat material demonstrated 2 prominent entities; a 90 kDa glycoprotein, which bound Datura stramonium agglutinin and was resistant to N- and O-glycanase treatment and a 47–60 kDa set of protein(s). Analysis of the surface lipids by electrospray mass spectometry revealed the presence of lysophosphatidic acid (lysoPA, C14[ratio ]2) and an unidentifiable component of 339·4 Da. These two lipids constituted 36·9% and 36% by mass of surface coat lipids respectively. The presence of lysoPA was confirmed by thin layer chromatography, which also detected phosphatidic acid (PA). The polar lipids detected in solvent rinses of intact parasites by electrospray mass spectrometry were PI (C48[ratio ]4), PE (C40[ratio ]4 and C38[ratio ]4), PS (C40[ratio ]4), lysoPC (C20[ratio ]2 and C18[ratio ]2) and lysoPA (C14[ratio ]2). These observations are discussed with respect to the role of the surface coat and its shedding in the T. spiralis host–parasite relationship.

scholarly journals An ultrastructural examination of the role of cell membrane surface coat material during neurulation.

1975 ◽  
Vol 64 (1) ◽  
pp. 172-181 ◽  
Author(s):  
D Moran ◽  
R W Rice
Keyword(s):  
Neural Tube ◽  
Membrane Surface ◽  
Progressive Increase ◽  
Cellular Migration ◽  
Surface Coat ◽  
Positive Material ◽  
Specific Distribution ◽  
Lateral Ridge ◽  
Coat Material

Data from neural crest cultures indicate that cell surface coat material (CSM) is directly involved in cellular migration and events surrounding differentiation. To investigate whether the CSM also has a morphogenetic role, embryos of the amphibian Ambystoma maculatum were examined ultrastructurally throughout the stages of neurulation. Segments of the neural axis were fixed in glutaraldehyde-containing Alcian blue 8GX, which reportedly enhances preservation of CSM, and were postfixed in OsO4 containing 1 percent lanthanum nitrate, which stains the CSM. The medial groove formed by the appearance of the neural ridges contains a large amount of CSM and numerous vesicles coated with lanthanum-positive material. In contrast, the lateral ridge surfaces are covered by a small amount of uniformly distributed CSM and a paucity of vesicles. As the ridges begin to fold there is a progressive increase in the amount of CSM within the presumptive neural tube region. Further convergence of the neural folds is accompanied by an increase of CSM at their leading edges. As the folds approximate each other, lanthanum-positive material physically bridges the gap. However, as the apposing tissue actually abuts to form the neural tube, no CSM is observed in the remaining interspace. The specific distribution and sequential accumulation of cell CSM during the events of neurulation strongly suggest its direct participation in the morphogenetic process.

scholarly journals Fibonectin is a component of the surface coat of human neutrophils

1981 ◽  
Vol 50 (1) ◽  
pp. 315-327
Author(s):  
S.T. Hoffstein ◽  
G. Weissmann ◽  
E. Pearlstein
Keyword(s):  
Cell Surface ◽  
Indirect Immunofluorescence ◽  
Neutrophil Function ◽  
Human Neutrophils ◽  
Surface Coat ◽  
Surface Material ◽  
Surface Distribution ◽  
Alpha 1 Antitrypsin ◽  
Covalently Linked ◽  
Coat Material

Although adherence to surfaces is central to neutrophil function many of the determinants of neutrophil adherence are still unknown. The possible involvement of cell surface material, fibronectin in particular, was therefore studied. Surface coat material was visualized ultrastructurally by the ferrocyanide—reduced osmium technique of Karnovsky (1971). Loosely attached surface coat material was seen distributed uniformly on cells in suspension. Indirect immunofluorescence indicated the presence of fibronectin on the neutrophil surface. Distribution of fibronectin as determined by indirect immunoferritin localization corresponded with the distribution of cell coat material. Some, if not all, of this fibronectin was synthesized by neutrophils themselves since metabolically labelled fibronectin could be obtained by immunoprecipitation after short-term culture with [36S]methionine. Neutrophils also adhere to Sepharose beads to which gelatin is covalently linked (GS) but not to plain Sepharose beads (PS). In the process they transfer surface coat material to GS but not PS. Similar transfer was seen when cells were permitted to adhere to glass or plastic coverslips. Indirect immunofluorescence showed that fibronectin-containing material was transferred from neutrophils to GS but not PS. Parallel studies with antisera to 2 other plasma proteins, factor VIIIR and alpha 1-antitrypsin showed that neutrophils did not transfer these to either GS or PS beads. The data suggest that material antigenically and functionally related to fibronectin is associated with the extracellular coat of neutrophils and is transferred with cell surface material to surfaces to which neutrophils adhere.

Surface coat material associated with the developing otic placode/vesicle in the chick

1988 ◽  
Vol 220 (2) ◽  
pp. 198-207 ◽  
Author(s):  
Allan R. Sinning ◽  
Mark D. Olson
Keyword(s):  
Surface Coat ◽  
Otic Placode ◽  
Coat Material

The Uptake of Methionine-S35 by the Chick Embryo and its Inhibition by Ethiònine

Development ◽  
1955 ◽  
Vol 3 (1) ◽  
pp. 44-58
Author(s):  
M. Feldman ◽  
C. H. Waddington
Keyword(s):  
Amino Acids ◽  
Chick Embryo ◽  
Protein Metabolism ◽  
Culture Medium ◽  
Molecular Size ◽  
Radioactive Isotopes ◽  
Surface Coat ◽  
Amphibian Embryo ◽  
Structural Analogues ◽  
External Sources

It seems probable that the synthesis of new proteins must play one of the most fundamental roles in embryonic development. As part of a programme of investigating protein metabolism in morphogenesis (see Waddington & Sirlin, 1954), a study has begun on the incorporation into the early chick embryo of amino-acids labelled with radioactive isotopes and the effect of some of their structural analogues on their metabolism. It seems that for this particular aspect of study the chick embryo has two main advantages over the amphibian: (1) Since it depends for metabolites on external sources (yolk, albumen, culture medium), it is much easier to interfere with the normal pathway of protein synthesis by means of specific antimetabolites. (2) Unlike the amphibian embryo, it does not possess a surface coat, which greatly inhibits the absorption of substances of even small molecular size in amphibian embryos (Friedberg & Eakin, 1949).

scholarly journals Activation for cell fusion in Chlamydomonas: analysis of wild-type gametes and nonfusing mutants.

1982 ◽  
Vol 92 (2) ◽  
pp. 378-386 ◽  
Author(s):  
U W Goodenough ◽  
P A Detmers ◽  
C Hwang
Keyword(s):  
Cell Fusion ◽  
Mating Type ◽  
Central Zone ◽  
Uranyl Acetate ◽  
Surface Coat ◽  
Wild Type ◽  
En Bloc ◽  
Mating Structure ◽  
Fusion Images ◽  
Coat Material

Gametes of Chlamydomonas reinhardi become activated for cell fusion as the consequence of sexual adhesion between membranes of mating-type plus and minus flagella. By using tannic acid plus en bloc uranyl acetate staining, and by fixing at very early stages in the mating reaction, we have demonstrated the following. (a) Activation of the minus mating structure entails major modifications in the structure of the organelle, causing it to double in size and to concentrate surface coat material, termed fringe, into a central zone. (b) The unactivated plus mating structure is endowed with fringe that moves with the tip of the actin-filled fertilization tubule during activation. Pre-fusion images suggest the occurrence of a specific recognition event between the plus and minus fringes. (c) Gametes carrying the imp-1 mutation fail to form a fringe and are unable to fuse. The imp-1 mutation is linked to the mating-type plus (mt+) locus, suggesting that the gene specifying the synthesis or insertion of fringe is encoded in this sector of the genome. (d) Gametes carrying the imp-11 mutation fail to form both a normal fringe and a normal submembranous density beneath the fringe, and are also unable to fuse. The imp-11 mutation converted a wild-type minus cell into a pseudo-plus strain; a model to explain this conversion proposes that the normal imp-11 gene product represses plus-specific genes concerned with Chlamydomonas gametogenesis.

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