scholarly journals Intracellular pH during calcification. A study of the avian shell gland

1969 ◽  
Vol 111 (5) ◽  
pp. 647-652 ◽  
Author(s):  
K. Simkiss
Keyword(s):  
Intracellular Ph ◽  
Domestic Fowl ◽  
Shell Gland ◽  
Shell Formation ◽  
Extracellular Water ◽  
Rapid Fall ◽  
Egg Shell

The intracellular pH of the shell gland of the domestic fowl was calculated at various stages in egg-shell formation. The calculation is based on the distribution of 5,5-dimethyloxazolidine-2,4-dione between intracellular and extracellular water. The results show a rapid fall in intracellular pH at the time of mineralization and this is interpreted as indicating a removal of protons from the site of calcification.

SULFONAMIDES AND EGG-SHELL FORMATION IN THE DOMESTIC FOWL

Science ◽  
1945 ◽  
Vol 101 (2633) ◽  
pp. 617-618 ◽  
Author(s):  
R. BERNARD ◽  
P. GENEST
Keyword(s):  
Domestic Fowl ◽  
Shell Formation ◽  
Egg Shell

A CYTOLOGICAL AND CYTOCHEMICAL STUDY OF THE SHELL GLAND OF THE DOMESTIC HEN

1953 ◽  
Vol 31 (6) ◽  
pp. 577-589 ◽  
Author(s):  
D. J. McCallion
Keyword(s):  
Shell Gland ◽  
Ciliated Epithelium ◽  
Shell Formation ◽  
Cytochemical Study ◽  
Negative Results ◽  
Inner Surface ◽  
Secretory Products ◽  
Egg Shell ◽  
Domestic Hen ◽  
Positive Results

A cytological and cytochemical study has been made of the oviducts of hens producing thick shelled eggs and of hens producing thin shelled eggs, with special reference to the shell gland. No significant differences between them were discovered. The inner surface of the oviduct of the hen is lined with ciliated epithelium containing two types of cells, ciliated and goblet. Lying under the ciliated lining are the tubular glands of the oviduct. The Golgi apparatus has been described in the several types of cells. The secretory products of these cells have been identified in the various parts of the oviduct. Small amounts of calcium were shown to be present in the oviduct by one of several techniques, the others giving negative results. Slight positive results were obtained for the presence of phosphates. Alkaline phosphatase was present in slight and varying amounts uniformly distributed in the oviduct, but acid phosphatase was confined to the ciliated epithelium. Glycogen was not present in the glandular tissues. The deposition of calcium as egg shell seems to be different from that in bone formation. Possible mechanisms of egg shell formation are discussed.

Shell gland and egg-shell formation in Fasciola hepatica L.

Parasitology ◽  
1953 ◽  
Vol 43 (1-2) ◽  
pp. 88-93 ◽  
Author(s):  
H. K. Yosufzai
Keyword(s):  
Fasciola Hepatica ◽  
Shell Gland ◽  
Shell Formation ◽  
Vitelline Cells ◽  
Egg Shell

1. The shell gland of Fasciola hepatica produces an extremely hyaline secretion. The egg-shell is formed from the hyaline secretion.2. As the eggs travel through the uterus, the shell is temporarily reinforced from the inside by vitelline granules. The vitelline granules are released when the vitelline cells enter the vitelline reservoir.3. Views regarding the nomenclature of the shell gland are discussed.4. The presence of an elliptical chamber in the shell gland is described. In this chamber, oocytes, vitelline granules and vitelline cells are mixed together, and here the secretion of the shell gland is released and the egg-shell is formed.5. The arrangement of the cellular constituents within the egg is effected by the elliptical chamber.

scholarly journals The Effect of Lithium Carbonate on Egg Shell Formation and Serum Calcium Level of the Hen

1971 ◽  
Vol 50 (2) ◽  
pp. 577-580 ◽  
Author(s):  
R.D. Creek ◽  
Pauline Lund ◽  
O.P. Thomas ◽  
W.O. Pollard
Keyword(s):  
Serum Calcium ◽  
Calcium Level ◽  
Serum Calcium Level ◽  
Lithium Carbonate ◽  
Shell Formation ◽  
Egg Shell

Role of magnesium in egg shell formation in the domestic hen

1991 ◽  
Vol 32 (4) ◽  
pp. 853-864 ◽  
Author(s):  
A. L. Waddell ◽  
R. G. Board ◽  
V. D. Scott ◽  
S. G. Tullett
Keyword(s):  
Shell Formation ◽  
Egg Shell ◽  
Domestic Hen

Radiographic Studies on the Formation of the Hen'S Egg Shell

1951 ◽  
Vol 28 (2) ◽  
pp. 125-140
Author(s):  
J. R. G. BRADFIELD
Keyword(s):  
Calcium Carbonate ◽  
Mineral Matter ◽  
Carbonate Content ◽  
Shell Gland ◽  
X Rays ◽  
Characteristic Structure ◽  
Hen’S Egg ◽  
Shell Deposition ◽  
Egg Shell ◽  
Pointed End

1. Radiographic methods have been used to study the rate of deposition of the hen's egg shell and the changes in volume and orientation undergone by the egg in the shell gland. 2. Shell deposition commences about 5 hr. after the yolk is ovulated and several series of radiographs were obtained tracing the process from these earliest stages through to the fully calcined shell. 3. From radiographs of calcium carbonate-gelatin mixtures it was found that, for a series of comparable objects differing only in calcium carbonate content, the densitometer readings on their radiographs were directly proportional to the density of calcium carbonate traversed by the X-rays in each object. 4. Hence, densitometer measurements on the periphery of the shell in each of a series of radiographs taken during the development of a single egg shell give values which are proportional to the density (or thickness) of calcium carbonate traversed by the tangential rays. It is shown that the radial thickness is closely proportional to the square of these values. 5. Plotting these squared densitometer readings against time indicates that the rate of deposition of mineral matter in the shell follows an S-shaped curve, with a marked acceleration in shell deposition 5-6 hr. after its onset. 6. During its first few hours in the shell gland, the egg undergoes a 25% osmotic increase in volume. This swelling is brought to a fairly abrupt halt by the increase in the rate of shell deposition and the consequent increase in the impermeability and rigidity of the shell. 7. Throughout all but the last hour or two of its 20 hr. stay in the shell gland, the egg lies with its pointed end caudal. Shortly before it is laid, however, it usually undergoes a 180° rotation in a horizontal plane. Thus the blunt end finally becomes caudal and emerges first when the egg is laid. During the rotation, the egg sinks to a more ventral position. This is necessary because, in most hens, the length of the egg plus the thickness of the walls of the shell gland is greater than the width of the pelvis. 8. The possible significance of the S-shaped curve of shell deposition is discussed. The volume, shape and orientation of the egg are considered in relation to the needs of the chick embryo and to the characteristic structure of the bird's oviduct and pelvis.

Studies on the structure of the female reproductive system and egg-shell formation inAspiculuris tetrapteraSchulz, (Nematoda: Oxyuroidea)

Parasitology ◽  
1964 ◽  
Vol 54 (4) ◽  
pp. 699-719 ◽  
Author(s):  
A. O. Anya
Keyword(s):  
Reproductive System ◽  
Shell Formation ◽  
Female Reproductive System ◽  
High Concentration ◽  
Classical Study ◽  
Quinone Tanning ◽  
Phenolic Substances ◽  
Egg Shell ◽  
Exogenous Origin ◽  
Aspiculuris Tetraptera

The histological anatomy of the female reproductive system of an oxyuroid nematode,Aspiculuris tetraptera, Schulz, has been described.The process of egg-shell formation in this animal has been followed in detail while the structural and chemical characteristics of the egg-shell have been studied by histochemical and other methods. It is shown that there are three layers: a lipoprotein layer, a ‘chitinous’ layer and the so-called vitelline (glycosidal) membrane. Evidence is presented for the exogenous origin of the lipoprotein layer: this being formed by the cells of the upper uterus which are shown to be secretory.The question of quinone-tanning in the egg-shell ofA. tetrapteraand in other oxyuroids and ascarids is considered. It is shown that neither a polyphenol oxidase nor a high concentration of phenolic substances (apart from protein tyrosine) exists in this system. The significance of these and other observations is discussed in relation to the mechanism of tanning as elucidated in insects and trematodes.I have to acknowledge with gratitude the support of many during these investigations. To Dr P. Tate for his encouragement and provision of facilities at the Molteno Institute; to Dr D. L. Lee, for much useful discussion and permission to refer to some of his unpublished electron micrographs of nematodes; to Professor J. D. Smyth, who kindly read through the manuscript; to the Cambridge Philosophical Society for a grant that made possible the translation of Fauré-Frémiet's classical study onAscaris;and to the Department of Technical Cooperation for financial assistance.

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