Fine Structure and Pinocytic Activity of the Visceral Epithelium of the Rat Yolk Sac Incubated in a Culture Medium with or without Goat Antirat-Placenta-IgG

1975 ◽  
Vol 154 (2) ◽  
pp. 170-181 ◽  
Author(s):  
H. Franke ◽  
T. Goetze ◽  
E. Goetze
Keyword(s):  
Fine Structure ◽  
Culture Medium ◽  
Yolk Sac ◽  
Visceral Epithelium

Characterization of protein production by caprine placental membranes: identification and immunolocalization of retinol-binding protein

1995 ◽  
Vol 146 (3) ◽  
pp. 527-534 ◽  
Author(s):  
K H Liu ◽  
J C Huang ◽  
J D Godkin
Keyword(s):  
Protein Production ◽  
Culture Medium ◽  
De Novo ◽  
Binding Protein ◽  
Yolk Sac ◽  
Retinol Binding Protein ◽  
Minimum Essential Medium ◽  
Placental Membranes ◽  
Extraembryonic Membranes

Abstract Caprine chorion, allantois and amnion from days 23, 28, 35, 39 and 45, and yolk sac from day 23 of pregnancy were isolated by dissection and cultured for 24 h in modified minimum essential medium in the presence of [35S] methionine. De novo-synthesized proteins released into the culture medium were analyzed by two-dimensional PAGE and fluorography. Patterns of protein production by these isolated extraembryonic membranes remained relatively unchanged from days 23 to 45 of pregnancy. Electrophoretic profiles of proteins synthesized by allantois and amnion were identical but distinct from that produced by chorion. Yolk sac was the major source of serum-like proteins. An acidic (pI 5·3–6·3) 22 kDa protein, which consisted of four isoelectric variants, was produced by all extraembryonic membranes and demonstrated to immunoreact with antiserum produced against bovine placental retinol-binding protein (RBP). Limited N-terminal sequence analysis of one major isoform indicated that the protein had complete homology with bovine RBP over the first 15 amino acids. Immunoreactive RBP was localized in epithelial cells lining the chorion, allantois and amnion. In this study, we have characterized and compared protein production by isolated extraembryonic membranes through days 23 to 45 of pregnancy and identified the 22 kDa protein as caprine RBP of placental origin. Journal of Endocrinology (1995) 146, 527–534

Effect of yolk-sac antibody on rat embryos grown in culture

Development ◽  
1972 ◽  
Vol 27 (3) ◽  
pp. 543-553
Author(s):  
D. A. T. New ◽  
R. L. Brent
Keyword(s):  
Direct Contact ◽  
Culture Medium ◽  
Gamma Globulin ◽  
Yolk Sac ◽  
Amniotic Cavity ◽  
Pregnant Rats ◽  
Rat Embryos ◽  
Visceral Yolk Sac ◽  
Primary Action

Rat embryos, explanted with their embryonic membranes during the early stages of organogenesis ( days gestation), were grown in culture in roller tubes. Yolk-sac antibody (sheep anti rat yolk-sac gamma globulin), known to be teratogenic when injected into pregnant rats, was added to the culture medium. At concentrations of 0·1 mg/ml or more the antibody caused gross retardation of growth and differentiation. Injection of antibody into the amniotic cavity so that it had direct contact with the embryo, or between the amnion and yolk sac so that it was in contact with the mesodermal surface of the yolk sac, had little or no effect on development of the embryo or its membranes. These in vitro experiments indicate that yolk-sac antibody has an effect on development independent of any immunological reaction of the mother, and the primary action is probably on the visceral yolk-sac endoderm.

The fine structure of the guinea pig visceral yolk sac placenta

1970 ◽  
Vol 127 (4) ◽  
pp. 397-413 ◽  
Author(s):  
Barry F. King ◽  
Allen C. Enders
Keyword(s):  
Fine Structure ◽  
Guinea Pig ◽  
Yolk Sac ◽  
Visceral Yolk Sac ◽  
Yolk Sac Placenta

Development in culture of rat foetuses explanted at 12·5 and 13·5 days of gestation

Development ◽  
1973 ◽  
Vol 29 (2) ◽  
pp. 473-483
Author(s):  
D. L. Cockroft
Keyword(s):  
Protein Content ◽  
Culture Medium ◽  
Yolk Sac ◽  
Gas Mixture ◽  
Rat Serum ◽  
Simple Operation ◽  
Flowing Medium ◽  
Economic Culture ◽  
Capillary Circulation ◽  
Somite Number

1. As a result of the relatively simple operation of opening the yolk sac and thus exposing the foetal capillary circulation to flowing medium, it has proved possible to grow 12·5- and 13·5-day rat foetuses for a period of 42 h in culture. 2. 25% rat serum, 75% Tyrode has been found to be a satisfactory and economic culture medium, and has the added attraction that foetal survival is improved compared with that obtained in whole rat serum. 3. For both 12·5- and 13·5-day foetuses grown with open yolk sacs, a gas mixture of 95% O2, 5% CO2 in equilibrium at 1 atm with culture medium flowing at about 15 ml/min has been found to give the best results. 4. Under these conditions, foetuses explanted at 12·5 days increased their protein content from 1·0–1·3 mg to 2·3–2·7 mg during culture. Their somite number was 40–44 at explantation and reached 50–55 during culture. 5. Foetuses explanted at 13·5 days increased their protein content from 3·2–4·0 mg to 6·1–7·5 mg during culture. Their somite number was 51–55 at explantation and reached 60–63 during culture.

scholarly journals Cultivation of Chlamydia trachomatis in cycloheximide-treated mccoy cells

1977 ◽  
Vol 6 (4) ◽  
pp. 328-331 ◽  
Author(s):  
K T Ripa ◽  
P A Mårdh
Keyword(s):  
Chlamydia Trachomatis ◽  
Culture Medium ◽  
Yolk Sac ◽  
Host Cells ◽  
Isolation Technique ◽  
Cover Slip

An isolation technique for Chlamydia trachomatis using McCoy cells is described. In contrast to earlier techniques employing such cells, no pretreatment of the cells was used. The glutarimide antibiotic cycloheximide was added to the culture medium used for incubating the cells after infection. Cycloheximide was used at concentrations that depressed, but did not completely inhibit, the metabolism of the eucaryotic host cells. In studies on different immunotypes of C. trachomatis cultured in the yolk sac of embryonated hen eggs, the cycloheximide technique was compared with a method using pretreatment of cells with 5-iodo-2-deoxyuridine. The cycloheximide method gave greater numbers of inclusion-forming units per cover slip for all the immunotypes of trachoma-inclusion conjunctivitis agents tested, i.e., A through I. In a study of 194 cervical and urethral specimens from women, cycloheximide treatment of McCoy cells was found to be more efficient than 5-iodo-2-deoxyuridine treatment for the isolation of C. trachomatis.

scholarly journals Inhibition of proteolysis in rat yolk sac as a cause of teratogenesis. Effects of leupeptin in vitro and in vivo

Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 183-193
Author(s):  
Stuart J. Freeman ◽  
John B. Lloyd
Keyword(s):  
Amino Acids ◽  
Protein Content ◽  
Culture Medium ◽  
Specific Inhibitor ◽  
Yolk Sac ◽  
Cysteine Proteinases ◽  
Rat Serum ◽  
Pregnant Rats ◽  
Stage Of Development

Conceptuses from 9·5-day pregnant rats were cultured for 48 h in heat-inactivated homologous serum to which leupeptin, a specific inhibitor of the lysosomal cysteine-proteinases, was added for the final or the penultimate 6h. The presence of leupeptin (25 µg/ml or above) increased the protein content of yolk sacs at harvesting to approximately twice the control value. The protein content of the embryo at harvesting was lower than that of controls. When 125I-labelled polyvinylpyrrolidone was added to the culture serum for the final 6 h of culture, radioactivity was found in the yolk sac at harvesting, but not in the embryo. The presence of leupeptin did not affect the rate of uptake of the radiolabelled macromolecule by the yolk sac, nor facilitate its entry into the embryo. When formaldehyde-denatured 125I-labelled bovine serum albumin was added to the culture medium for the final 6 h of culture, little radioactivity was found in the yolk sac at harvesting, and barely any was found in the embryo. Trichloroacetic acid-soluble radioactivity was found in the culture serum. The presence of leupeptin sharply increased the levels of radioactivity in the yolk sac (but not the embryo) and sharply decreased the acid-soluble radioactivity of the culture medium. When rat serum whose proteins were labelled with [3H]leucine was used as culture medium, radioactivity was found in both yolk sac and embryo at harvesting. The presence of leupeptin increased the amount found in the yolk sac and decreased that found in the embryo. These results are interpreted as follows. Leupeptin enters the lysosomes of the yolk sac, inhibiting their cysteine proteinases. The digestion of proteins pinocytosed by the yolk sac is consequently inhibited, resulting in the accumulation of protein by the yolk sac and a decreased flow of amino acids to the embryo. Leupeptin (50 mg/kg), injected into pregnant rats at either 8·5 days or 9·5 days of gestation, induced congenital malformation in the offspring. It is proposed that leupeptin exerts its teratogenic action by inhibiting proteolysis in the lysosomes of the yolk sac, and so depriving the developing embryo of its supply of amino acids at a critical stage of development.

scholarly journals Rate of pinocytic capture of macromolecular substrates by rat yolk sac incubated in serum-free culture medium

1979 ◽  
Vol 178 (3) ◽  
pp. 785-792 ◽  
Author(s):  
G E Ibbotson ◽  
K E Williams
Keyword(s):  
Plasma Membrane ◽  
Quantitative Analysis ◽  
Binding Sites ◽  
Culture Medium ◽  
Serum Proteins ◽  
Calf Serum ◽  
Yolk Sac ◽  
Serum Free ◽  
High Affinity ◽  
Lysosomal System

Pinocytic activity was quantified for rat yolk sacs incubated in a medium that was either serum-free or contained 10% (v/v) of calf serum. Absence of serum from the medium caused a small increase in the rate of pinosome formation, as determined by the rates of capture of both 125I-labelled poly(vinylpyrrolidone) and [14C]sucrose. In contrast, the rates of uptake of substrates ingested by adsorptive pinocytosis were greatly enhanced when serum proteins, which compete for the same binding sites on the plasma membrane as used by adsorbing substrates, were absent. Elimination of such competition greatly simplifies the quantitative analysis of the binding process, and permitted a detailed study of the binding to the plasma membrane of formaldehyde-denatured bovine serum albumin, a protein that is rapidly digested within the lysosomal system after its pinocytic capture. Binding obeyed Michaelis-Menten kinetics and showed a dissociation constant of approx. 1 micron, indicating the high affinity of this protein for binding sites on the surface of actively pinocytosing yolk-sac cells.

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