bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics of five cell types appearing during in vitro culture of embryonic material from Drosophila melanogaster
Authors: Shields Glen , Sang James H. 
Published: April 2021

ABSTRACT
Although attempts have been made over a number of decades to achieve successful tissue culture of Drosophila material (see Schneider, 1964), progress has been held back until recently by a lack of basic information on the chemical and physiological characteristics of the haemolymph of the organism necessary for a reasoned formulation of a culture medium. In 1963, Begg & Cruickshank published details of the mineral composition, osmotic pressure and pH of the haemolymph of third instar larvae, and this has provided the basis for a more satisfactory approach, as reflected in an increasing amount of fruitful work since reported. Much of this work has been done with embryonic material. Horikawa & Fox (1964) claimed continuous multiplication of a small type of early embryonic cell; Lesseps (1965) described re-aggregation of dissociated embryonic cells in culture, with possible development of muscle cells, nerve cells and oenocytes in the aggregates; in the same year, Echalier, Ohanessian & Brun (1965) noted the emergence of free contractile elements and a polygonal type of cell in embryonic cultures, with the later development of a fibroblastic type of cell; Gvozdev & Kakpakov (1968) reported the appearance of a small type of cell growing in multilayer clumps as well as of fibroblast-and epithelial-type cells, and Seecof & Unanue (1968) reported the development of free neuron-like cells and muscle cells. Results are presented below of a further investigation into the behaviour of Drosophila melanogaster embryonic cells in culture, and the characteristics of five distinct cell types are described. These comprehend the types mentioned above (and to some extent there is necessarily repetition of the earlier work) but, as well as bringing the previously isolated observations into a single study, greater detail is given of the form and mode of development of the elements, and some account of the dynamic activities of some of them is included.
An inverse relation between the rate of cell division and RNA synthesis per cell in developing frog embryos
Authors: Flickinger R. A. , Lauth M. R. , Stambrook P. J. 
Published: April 2021

ABSTRACT
Previous work has shown that endoderm cells synthesize more RNA per cell, including nuclear d-RNA, than do dorsal ectoderm-mesoderm cells (Flickinger, Miyagi, Moser & Rollins, 1967; Woodland & Gurdon, 1968). Both groups found lower levels of DNA synthesis in endoderm cells compared to dorsal ectoderm-mesoderm cells. It has also been found that in developing frog embryos both LiCl and cytosine arabinoside inhibit DNA synthesis and also inhibit RNA synthesis. Since RNA synthesis is inhibited less than DNA synthesis, the levels of RNA synthesis relative to total DNA increase (Flickinger, Miyagi, Moser & Rollins, 1967). A number of investigators have demonstrated that LiCl can cause isolated amphibian gastrula ectoderm to form endoderm and mesoderm (Barth & Barth, 1962; Gebhardt & Nieuwkoop, 1964; Masui, 1966; Ogi, 1961). Such compounds as NaHCO3 (Barth & Barth, 1963) and NaCl (Barth, 1966) can induce isolated frog gastrula ectoderm to form neural tissue.
Growth and metabolism in snake embryos
Authors: Dmi’el Razi 
Published: April 2021

ABSTRACT
Since the early papers of Bohr & Hasselbalch (1900, 1903) and Murray (1925), considerable information concerning the growth and metabolic processes in the avian embryo has been accumulated (Romanoff, 1967). Respiratory and growth processes during embryonic life in many species of fishes, amphibians and mammals are also fairly well known. Only a few studies have been reported, however, on the metabolism and growth of the reptilian embryo. Lynn & Brand (1945) presented a detailed description of these processes in four species of turtles. Some data on respiration in the egg of the snake Coluber natrix are given by Bohr (1904). The respiration of four eggs a few days prior to hatching in the snake Liopeltis vernalis was studied by Zarrow & Pomerat (1937). Scattered information on the embryonic growth of snakes may also be obtained from papers dealing with the development of certain anatomical systems in the embryo, such as venom glands and the musculature related to them (cf. Fukada, 1958; Kochva, 1963, 1965). Growth or metabolic curves are not available for snake embryos, however.
Isolation and partial characterization of amphibian tyrosine oxidase polysomes
Authors: Triplett E. L. , Herzog R. , Russell L. P. 
Published: April 2021

ABSTRACT
A population of polysomes isolated from frog skin is capable of supporting protein synthesis in a cell-free system containing an energy generating system, ‘soluble components and amino acids.
These polysomes catalyse the oxidation of DOPA after gentle trypsinization, and they also have antigenic determinants attributable to tyrosine oxidase.
Skin polysomes sedimented in 10–30% sucrose gradients contain tyrosine oxidase peaks of enzymic activity at the bottom and top of the tube and in the 250 S regions. A peak of tyrosine oxidase antigenic acitvity is found in the 250–350S region of the gradient.
Polysomes resolved on the gradient retain the ability to support protein synthesis in a cell-free system. All 250–350 S particles capable of supporting the incorporation of [14C]amino acid into tyrosine oxidase are precipitable with tyrosine oxidase antibodies. It is probable that 25O–35OS tyrosine oxidase antibody precipitates contain only polysomes for this protein.
Immunochemical analysis of the water-soluble fraction of the chick embryo yolk
Authors: Grossi C. E. , Carinci P. , Manzoli-Guidotti L. 
Published: April 2021

ABSTRACT
By means of immunochemical techniques, the protein components of the water-soluble fraction (WSF) of the egg yolk have been examined in the unincubated egg and during incubation.
Anti-ovalbumin and anti-total adult chicken serum antisera have been employed.
Ovalbumin can be detected in the unincubated WSF as well as during incubation; its concentration seems to increase during incubation.
In the WSF of the unincubated egg, six proteins immunologically related to adult serum proteins can be detected. They correspond to α-livetin, α1-globulin, β-livetin, ovotransferrin (conalbumin) and γ-livetin (two components). β-Livetin disappears after the 14th day of incubation while the other components can be demonstrated till hatching.
The findings are discussed in relation to the data available in the literature.
Tissue interactions in embryonic mouse tooth germs: I. Reorganization of the dental epithelium during tooth-germ reconstruction
Authors: Kollar Edward J. , Baird Grace R. 
Published: April 2021

ABSTRACT
The ability of fragments of incisor enamel organ and lip-furrow epithelium from 15-and 16-day old embryonic mice to regulate into harmonious tooth constructions is described. The cervical loop and upper half portions of the incisor enamel organ were confronted with incisor or molar dental papillae. Similar combinations were made from lip-furrow epithelium and incisor or molar papillae. The cultures were grown in the anterior chambers of homologous host eyes.
The epithelial fragments from the incisor enamel organ when associated with the dental papillae reconstruct teeth typical in all respects; enamel and dentin matrices are deposited.
Lip-furrow epithelium arises from the oral epithelium and is temporally and spatially related to the incisor dental epithelium proper. This ectopic epithelium was confronted by incisor and molar papillae. Harmonious teeth developed in these explants.
It is concluded that the ability of the dental papillae to elicit new cytodifferentiative and biochemical syntheses from the lip-furrow epithelium indicates that the dental papillae act inductively during tooth ontogeny.
The shape of the teeth reconstructed from enamel organ fragments and lip-furrow epithelium were incisiform or molariform in response to the incisor or molar dental papillae. These data confirm the conclusion that the structural specificity for tooth shape resides in the dental papilla.
Interspecific relationships of oviducal materials as related to fertilization in Amphibia
Authors: Shaver John R. , Barch Stephanie H. , Umpierre Carmen C. 
Published: April 2021

ABSTRACT
Experiments are described in which eggs of Rana species were treated prior to insemination with antisera prepared against oviducal materials of Rana, Bufo, and Ambystoma species. Three types of treatment with antisera were employed.
Eggs of Rana pipiens and R. clamitans were treated with antisera against materials prepared from whole oviducts, or from upper and lower segments of oviducts, of R. pipiens, R. clamitans, R. sylvatica, R. catesbeiana, Bufo americanus, B. marinus and Ambystoma mexicanum.
Eggs of R. pipiens were treated with antisera against materials from whole oviducts, or from upper, middle or lower oviducal regions, of R. pipiens, which had been absorbed with materials from whole oviducts of the species named above.
Eggs of R. pipiens were treated with antisera against materials from whole oviducts, or from upper, middle or lower oviducal segments of R. pipiens, which antisera had each been absorbed with material from whole, upper, middle or lower oviducts of Rana species.
The results indicated that treatment with antisera against oviducal materials of Rana origin was inhibitory to fertilization of Rana eggs, while treatment with antisera against oviducal materials from other amphibian genera was not.
The experiments with absorbed antisera indicated that the secretion by the oviducts of R. pipiens of components also occurring in other Rana species is regionally localized in the oviduct.
The relationships of secretions of amphibian oviducts to fertilization is discussed in connexion with the histochemically demonstrable complexity of the jelly envelopes around eggs.
Morphogenesis in hydra:II Peduncle and basal disc formation at the distal end of regenerating hydra after exposure to low temperatures
Authors: Corff Sondra C. , Burnett Allison L. 
Published: April 2021

ABSTRACT
When Hydra oligactis is excised below the tentacles and incubated for a short time in concentrations of colchicine that inhibit spindle formation in dividing cells, a peduncle and basal disc subsequently form at the cut distal end, where hypostome and tentacles normally form (Corff & Burnett, 1969). Since recent reports suggest a similarity in the action of colchicine and low temperature, in this study the effects of low temperatures on regenerating hydra were investigated. High hydrostatic pressure and low temperature have been shown to act synergistically with colchicine to inhibit the first mitotic division in sea urchin eggs (Marsland, 1968). Colchicine and cooling have also been shown to cause disintegration of the microtubule system in Actinosphaerium (Tilney, 1965).
The transplantation of nuclei from single cultured cells into enucleate frogs’ eggs
Authors: Gurdon J. B. , Laskey R. A. 
Published: April 2021

ABSTRACTNuclei from a monolayer of cultured epithelial cells have been transplanted singly to enucleated unfertilized eggs of Xenopus laevis.About three-quarters of the injected eggs failed to cleave or cleaved abortively. Most of the remainder formed partial blastulae. Less than 1 % reached postneurula stages of development.Nuclei from first-transfer blastulae were used for serial transplantation. The nuclei of partial blastulae promoted normal or nearly normal development more often than those of complete blastulae. Several clones were obtained which included nearly normal tadpoles with apparently normal muscle, nerve, blood, and other specialized cell types. Three tadpoles commenced feeding and have completed metamorphosis into young frogs.To prove that the donor- and not egg-nucleus participated in the formation of nuclear-transplant tadpoles, genetically marked 2-nu and l-nu diploid nuclei were transplanted to 2-nu eggs; the resulting tadpoles had the nucleolar number characteristic of donor, not egg, nuclei. Chromosome counts and nuclear diameter measurements on the epidermal cells of these tadpoles revealed the presence of diploid mitoses and the absence of haploid nuclei.The behaviour of egg and donor nuclei immediately after nuclear transfer was determined by tracing the early cleavage pattern of individual eggs and by following, autoradiographically, the fate of donor nuclei whose DNA had been previously labelled with 3H-thymidine.These experiments show that the serial transplantation of nuclei from monolayer cell cultures can lead to sufficiently normal nuclear-transplant embryo development to provide a useful test of the genetic properties of the donor cell line.
Protein transmission across the rabbit foetal membranes
Authors: Wild A. E. 
Published: April 2021

ABSTRACTFluorescent protein tracing, involving F.I.T.C.-conjugated proteins and the fluorescent antibody technique, was employed to study the sites and mechanism of transport of a variety of proteins across the rabbit foetal membranes.No evidence was found for an intercellular transmission of proteins across the yolk sac splanchnopleure to the exocoel, but all proteins were shown to become localized in absorptive vesicles in the yolk-sac endoderm.Different proteins became similarly localized in absorptive vesicles having different sizes and profiles. Characteristic broken vesicles were present, and more than one protein was demonstrated in each absorptive vesicle.The yolk-sac endoderm was confirmed as the selective site for transmission of proteins to the foetal circulation, since only proteins readily detected in the foetal serum were present in, and below, the basement membrane.The paraplacental chorion was shown to be the site for transmission of proteins to the exocoel and the process to be one of diffusion.Unlike normal proteins, F.LT.C. conjugates readily became localized within macrophages present in the paraplacental chorion and yolk-sac vascular mesenchyme.These findings are discussed in the light of differences previously shown to occur between transmission of proteins to the foetal fluids and to the foetal blood, and in the light of a current hypothesis to account for selection of proteins by the yolk-sac endoderm.
Capacité de régulation des excédents dans la crête neurale d’Amphibien
Authors: Chibon Par P. 
Published: April 2021

ABSTRACT
L’étude des possibilités de régulation des excédents dans la crête neurale, au moyen d’implantation de fragments de crête neurale surnuméraire marquée par la thymidine tritiée conduit aux résultats suivants:
L’implantation d’un fragment de crête neurale surnuméraire n’entraîne aucune anomalie grave.
La migration des cellules surnuméraires et leurs localisations finales sont identiques à celles des cellules de la même région de la crête neurale, dans les conditions normales. La régionalisation de la crête neurale est donc maintenue.
Le marquage issu de ces opérations est toujours unilatéral; de ce côté les cellules marquées et les cellules de l’hôte se mélangent pour former en commun des dérivés dont le nombre ou la taille sont identiques à ceux des témoins.
Une régulation parfaite se réalise donc du côté opéré, sans retentissement du côté opposé.
Du côté opéré, il se produit une modification du comportement mitotique des cellules des crêtes neurales mises en présence.
Studies on mitochondria in the early development of the slug Arion ater rufus L
Authors: Sathananthan A. H. 
Published: April 2021

ABSTRACT
The structure, distribution, cytochemical nature and functional significance of mitochondria have been studied during the embryogenesis of the slug Arion, from the ovum to the postgastrula stage.
Mitochondria seem to undergo progressive but profound changes in form and fine structure during early development and their distribution conforms to a gradient pattern, which more or less resembles that of the sea urchin.
The most significant event in cyto-differentiation is the appearance of an extraordinary vegetal aggregation of mitochondria at the 8-cell stage which heralds a vegetalizing influence and undoubtedly has a precise morphogenetic function. This vegetal aggregation becomes involved in a remarkable series of morphogenetic movements and its mitochondria are later incorporated into the cells that differentiate into mesoderm and endoderm. Thus, apart from their energy-linked functions, mitochondria seem to play a dramatic directive role in development; mitochondrial segregation, in particular, seems to be the important factor in differentiation.
Certain aspects of their distribution and enzymic composition are discussed in relation to their normal metabolic functions.
The significance of mitochondrial RNA and DNA with reference to protein synthesis and self-duplication of mitochondria, and the possible roles played by mitochondria in inductive phenomena are also discussed in the light of recent work.
Effect of colcemid on the locomotory behaviour of fibroblasts
Authors: Vasiliev Ju. M. , Gelfand I. M. , Domnina L. V. , Ivanova O. Y. , Komm S. G. , Olshevskaja L. V. 
Published: April 2021

ABSTRACT
Effects of metaphase inhibitors (colcemid, colchicine, vinblastine) on mouse and human embryonic, fibroblast-like cells growing on glass and on an oriented substrate (fish scale) were studied. All three inhibitors caused similar changes in the form of interphase cells and inhibited their directional locomotion. The effects of two inhibitors (colcemid and vinblastine) were found to be completely reversible. Microcinematographic studies have shown that the most conspicuous change of locomotory behaviour induced by colcemid was the disappearance of non-active stable parts of the cell edge; in normal cells only the leading part of the edge was actively moving, while in colcemid-treated cells all parts of the edge eventually became active. Activation of the whole edge made these cells unable to perform directional translocation.
It is suggested that colcemid and other metaphase inhibitors prevent stabilization of the non-active state of the cell surface. The possible role of this suggested colcemid-sensitive stabilization mechanism in the normal locomotory behaviour of fibroblasts is discussed.
Electron-microscopic examination has shown that microtubules disappeared from the cytoplasm of colcemid-treated, mouse, fibroblast-like cells. The formation of microtubules as the possible structural basis of the stabilization of the non-active state of the cell surface is discussed.
Le canal de Wolff induit la formation de l’ostium müllérien: démonstration expérimentale chez l’embryon de Poulet
Authors: Didier Par Eliane 
Published: April 2021

ABSTRACT
The Wolffian duct induces the formation of the ostium of the Müllerian duct: demonstration in the chick embryo
An experimental analysis of the part played by the Wolffian duct in the formation of the ostium of the Müllerian duct has been made by blocking the Wolffian duct in front of and at different levels of the presumptive ostial area.
If the Wolffian duct is blocked between somites 13 and 19, the ostium and a short Müllerian duct always arise beside the developed part of the Wolffian duct.
If the blocking is performed between somites 9 and 13 there is no development of the ostium or Müllerian duct.
The influence of mesenchyme on the epithelial glycogen and budding activity in mouse embryonic lung developingin vitro
Authors: Alescio T. , Dani A. M. 
Published: April 2021

ABSTRACTExperiments have been performed to show the association of epithelial glycogen with budding activity, and their dependence on the nature of the associated mesenchyme.The bronchial mesenchyme associated with the tracheal epithelium induces the appearance of a tracheal bud where glycogen remains present after its removal from the rest of the trachea.The bronchial mesenchyme associated with the tracheal epithelium after the normal disappearance of glycogen, still induces the formation of an epithelial bud where glycogen is clearly demonstrable.The primary left bronchus completely ceases its budding activity when brought in association with metanephrogenic mesenchyme ; glycogen is totally absent from the resting epithelium.The reassociation of the morphogenetically quiescent primary left bronchus with bronchial mesenchyme brings about resumption of budding activity and reappearance of the epithelial glycogen, showing normal bronchial distribution.
Différenciation du trophoblaste au cours du développement in vitro d’embryon de Souris
Authors: Hernandez-Verdun Par D. , Legrand C. 
Published: April 2021

ABSTRACT

Differentiation of the trophoblast during in vitro development of the mouse embryo
Mouse embryos obtained at the presomitic stage develop in vitro up to 70 h. During the first 24 h development remains comparable in vitro and in utero. Afterwards, the chronology of embryonic development is modified and in our successful prolonged experiments (70 h culture), foetal organogenesis reaches a stage corresponding only to days in utero. In some instances a chorioallantoic circulation has been observed in the umbilical cord.
The three trophoblast cell types present in egg-cylinders at 8 days post coitum, develop in the same way in utero or in vitro. After 48 h culture electron microscopy shows that numerous annulate lamellae appear in the nuclei and in the cytoplasm of some of the giant cells. The syncytium does not differentiate between the trophoblast and the allantoic mesoderm. The haemo-trichorial placental barrier does not differentiate in vitro, although foetal capillaries form.
In vitro, the endoderm cells (from the splanchnopleure or from the omphalopleure) actively proliferate and form an homogeneous substance located between the giant and the polyhedric trophoblast cells.
Exocrine glands and the Chievitz organ of some mouse mutants
Authors: Grüneberg Hans 
Published: April 2021

ABSTRACT
Thirteen mutant genes of the mouse have been scanned for the occurrence of anomalies of glands of the head region and of the Chievitz organ. In eight of these (ic/ic, my/my, Ph/Ph; Xt/Xt, Cd/Cd; fi/fi; or/or and ch/ch) such anomalies have been discovered; most of them are absence or reduction in size of a gland, but increases in size or numbers have also been seen. The anomalies are mainly and possibly entirely local consequences of pre-existing abnormalities of other organs and thus different from the systemic effect of the tabby syndrome. But in at least one instance no local cause for an isolated glandular defect has been discovered.