bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Remarkable Case of Animalization in a Batch of Eggs of Paracentrotus lividus
Authors: Hörstadius Sven , Gustafson Tryggve 
Published: April 2021

ABSTRACT
Sea-urchin eggs generally develop quite normally after artificial fertilization. Sometimes it may be difficult to obtain good membrane elevation, but, after repeated washing in sea-water, fertilization and further development may be quite normal. In some batches of eggs abnormalities may, however, be observed in the pluteus stage, but these abnormalities, as a rule, do not change the pattern of the larvae profoundly. The defects are generally restricted to the arms and to the skeletal rods which, for example, may fail to grow out to their normal length, or may bend in an abnormal direction. Supernumerary rods may also appear, and rods may grow in an abnormal direction inside the larval body without causing a change in the exterior of the pluteus. During many years of experimental work with sea-urchin eggs, for the senior author dating thirty years back, we have never encountered, nor have we seen in the literature, examples of such an abnormal development as the one described in this paper.
Les ions de métaux lourds et le problème de la détermination embryonnaire chez les Échinodermes
Authors: Lallier R. 
Published: April 2021

ABSTRACT
The animalizing effects of zinc on the development of eggs of the sea-urchin, Paracentrotus lividus, were studied and compared with the effects of other closely related metals: nickel, cobalt, manganese, and iron.
Nickel chloride (1/1,000) suppressed the formation of an archenteron. The blastulae were covered with short cilia. The apical tuft was not formed.
Nickel chloride (1 / 5,000 and 1110,000) induced the formation of radial larvae.
Cobalt chloride disturbed gastrulation and inhibited development.
Zinc was detected in the embryos at various stages of development by the formation of a deep red colour with dithizone. Zinc appeared to be distributed in the mesenchyme and entoderm of the young stages. In the pluteus, it appeared to be fixed in the pigment cells.
Nickel was located by the colour reactions with dimethylglyoxime and a-furil-dioxime. The colour was developed in the mesenchyme of the young blastula.
The colour reaction with dithizone was not modified by previous washings with Complexone (ethylene-diamine tetra-acetic acid) solution.
Zinc fixed in the embryos could be displaced by mercury ions.
With the addition of p-chloro-mercuribenzoic acid, the development of embryos in zinc chloride was blocked. The sulfhydryl groups do not appear to be essential for animalization by zinc ions.
The role of zinc in the animalization of sea-urchin eggs is discussed as a function of the formation of complexes between metal and proteins.
Action de la dicarnitine’ sur la croissance et l’ossification d’ébauches de tibias et de fémurs d’embryons de poulet cultivés in vitro
Authors: Lièbecq-Hutter Suzanne 
Published: April 2021

ABSTRACT
Tibias and femurs of 7-day-old chick embryos were cultivated in the absence and in the presence of racemic dicarnitine on a solid medium (fowl plasma + embryo extract, the latter usually diluted 20-to 200-fold). The growth in length of the bones was increased by 1/3 to 2/3 in comparison with the controls, when 2·5 and 5 mg. / I. of dicarnitine was added and when the embryo extract was not diluted more than 100-fold. With embryo extract diluted 200-fold, the shape of the bone was abnormal. Dicarnitine in this case restored the normal shape without increasing the elongation. Dicarnitine in a medium containing embryo extract diluted 200-fold was found to increase the maximal thickness of the periosteal bone in comparison with the controls. This effect was statistically highly significant in the case of dicarnitine concentrations of 2·5 and 5 mg./l. The effect was not found with non-diluted embryo extract. Mitoses were counted in tibias and femurs cultivated in vitro for periods of 1 to 7 days. 2·5 mg./l. dicarnitine was shown to promote mitotic activity. In the periosteum, it maintained for 4 days a mitotic activity equal to 45 per cent, of the mitotic activity in vivo. In vitro controls retained only 6 per cent, of this activity. The usefulness of frequent transfers was demonstrated. The percentage of prophases was higher in the periosteum than in the epiphyses. The relative frequency of metaphases increased with the age of the cultures. The frequency distribution of the phases of mitosis was shown to be very little changed by dicarnitine. After 7 days of culture, the number of cells was more increased in the hypertrophic cartilage than in other tissues. Dicarnitine did not much increase the total number of cells; there was practically no effect on the number of cells of the epiphyses but a large increase in the number of cells of the periosteum and of the hypertrophic cartilage was observed.
Interdigital cell death during limb development of the turtle and lizard with an interpretation of evolutionary significance
Authors: Fallon John F. , Cameron Joann 
Published: April 2021

ABSTRACT
Cell death accompanies the formation of free digits in birds and mammals. However, in species with webbing between the adult digits, little or no cell death occurs in the prospectively webbed region of the developing interdigit. Cell death does not occur during the formation of free digits in amphibians. In this paper we report that cell death accompanies the formation of the digits in snapping and painted turtles and in the skink (a lizard). We conclude that cell death accompanying the formation of free digits had its origin at the point of amniote emergence during evolution.
L’activité3β-hydroxystéroïde déshydrogénasique dans les gonades en différenciation dePleurodeles waltlii(Amphibien, Urodèle); visualisation sur coupes sériées à l’aide d’une nouvelle technique histochimique
Authors: Collenot G. , Collenot A. 
Published: April 2021

ABSTRACT3βHydroxysteroid dehydrogenase activity in the larval gonads of Pleurodeles waltlii (amphibian, urodele); a new histochemical technique for serial sections.In order to detect a 3β-hydroxysteroid dehydrogenase (3β-HSDH) activity in the larval gonads of the newt Pleurodeles waltlii an original histochemical method has been derived from the cytochemical technique used by Bara & Anderson (1973) in their ultrastructural studies on the same enzyme activity. The new technique which is described here, allows the incubation in toto of the larval gonads, their paraffin embedding and their sectioning into serial sections of 7 /tm thickness. Unisexual, male and female, offsprings were used.The 3β-HSDH activity could be detected, in the larval gonads, at the level of the inner cells which constitute the medulla inside the cavity of the genital ridge, as early as the end of the first third of the larval life, at a stage when the gonads are not yet differentiated. When an ovary differentiates, the enzyme activity remains at the level of the ovarian sac which will constitute the theca of the follicles in the mature ovary. When a testis differentiates, the medullary positive cells which associate with the germinal cells constitute the testicular ampullae or cysts and (later) become negative; but, at the level of the posterior part of the testis, several clusters of interstitial cells showed a 3β-HSDH activity in metamorphosed and juvenile animals.The results are discussed in relation with former reports about the steroid-synthesizing cellular sites in the mature ovaries and testes of urodelean amphibians.
Application of a morphological time scale to hereditary differences in prenatal mouse development
Authors: Wahlsten Douglas , Wainwright Patricia 
Published: April 2021

ABSTRACTA standardized morphological time scale for prenatal mice is presented, which is useful from 13·0 to 17·0 days chronological age with an accuracy of 0·1 day. Morphological age for an embryo or fetus is shown to correlate highly with ages estimated from body weight and crown-rump length. The time scale is used to study the comparative development from 14 to 17 days prenatal age of an F2 and four inbred mouse strains. The F2 mice average 0-5 day ahead of C57BL/6 mice, and C57BL/6 mice average 0·5 day ahead of A, BALB/c, and, at some ages, DBA/2 mice. Using reciprocal F1 crosses and reciprocal backcrosses, it is also shown that both the fetal heredity and the maternal environment contribute significantly to the more advanced development of hybrid mice.
Delayed appearance of ectodermal cell death as a mechanism of polydactyly induction
Authors: Scott William J , Ritter Edmond J. , Wilson James G. 
Published: April 2021

ABSTRACTThe temporal program of cell death in the apical ectodermal ridge and mesoderm of rat embryo hindlimbs was documented using supravital staining with Nile blue sulfate. Dye uptake indicative of cell death began postaxially at about 290 h of development and was followed in a few hours by preaxial staining, which became more extensive and intense up to 313 h.Two agents which cause preaxial polydactyly, cytosine arabinoside and 5-fluorodeoxy-uridine, postponed the onset of preaxial ectodermal cell death while at the same time having the expected cytotoxic effect on limb-bud mesoderm. In addition, a zone of deep preaxial mesodermal necrosis, thought to control the size of digit 1 in normal embryos, was usually absent in cytosine-arabinoside-treated embryos.The results suggest that the prolonged survival of ectodermal cells effected an increased inductive activity on the underlying mesoderm, leading to the formation of excess digital tissue. The data further suggest that the rate at which mesodermal cells were killed affected the subsequent delay of ectodermal cell death.
Cartilage matrix deficiency (cmd) : a new autosomal recessive lethal mutation in the mouse
Authors: Rittenhouse E. , Dunn L. C. , Cookingham J. , Calo C. , Spiegelman M. , Dooher G. B. , Bennett D. 
Published: April 2021

ABSTRACT
A new autosomal recessive lethal mutation in the mouse designated cartilage matrix deficiency (cmd) is described. Homozygotes are dwarfed, and have abnormally short trunk, limbs, tail and snout, as well as a protruding tongue and cleft palate. The abdomen is distended because the foreshortened rib cage and spinal column forces the liver ventrad from its normal location. Histological and electron microscopic study reveals a deficiency of cartilage matrix in tracheal cartilage and in all cartilagenous bones examined. The syndrome closely resembles the rare lethal condition achondrogenesis, found in human infants, which is also believed to be due to an autosomal recessive gene.
Functions of the Lymph Gland Cells during the Larval Period in Drosophila
Authors: El Shatoury H. H. , Waddington C. H. 
Published: April 2021

ABSTRACT
In the latter half of the second instar the lymph glands of Drosophila larvae hypertrophy and release cells into the body-cavity, many of which move to the imaginal buds (Shatoury, 1955a). These cells have been referred to as oikocytes. The optic region of the cephalic disk becomes colonized by the large cells known as hexagons. During the first half of the third instar these increase considerably in number. At about the 85-hour stage, and simultaneously with similar changes in the cells still in the lymph glands, the oikocytes in the optic disk exhibit nuclear pycnosis and the deposition of melanin. Later the cells may become vacuolarized and disintegrate. The precursors of the ommatidia can be seen in the optic disk before the oikocytes become melanized. During the latter part of the first instar oikocytes are also released from the lymph glands, and hexagons accumulate around the end of the oesophagus where it enters the proventriculus. In the immediate neighbourhood of these oikocytes the radial layer of the proventriculus shows some cellular differentiation, forming an ‘upper ring’ of highly basophilic cells. It has usually been considered that this upper ring constitutes the primordia of the imaginal fore-gut, but it has been found that the lower radial cells will also contribute to this structure. The oikocytes of the proventriculus suffer melanization and degeneration at the same time as those of the optic disk and the lymph gland. In larvae aged between 85 and 96 hours two groups of degenerating cells can be found near the cephalic end of the testis and one group in the caudal end. These three groups of cells seem to be oikocytes, and can be traced back to the first instar, when they seem to enter the testis at the same time that the proventriculus is being colonized. Their appearance in the testis is followed by the first sign of the differentiation of spermatocytes. The appearances suggest that the oikocytes, when they arrive at the testis, the proventriculus and the optic disk, play some part in stimulating those processes of differentiation which bring these organs into the condition from which they can undergo metamorphosis. The simultaneous degeneration of these cells at the end of the third instar would seem to indicate that this stimulus is no longer needed after that time. Shatoury (1956) has suggested that the mechanism which brings about this degeneration involves the formation of auto-antibodies.
A Critical Period for the Turning of Hens’ Eggs
Authors: New D. A. T. 
Published: April 2021

ABSTRACT
Turning hens’ eggs between the 4th and 7th day of incubation gives a hatchability similar to that of eggs turned throughout incubation. Turning the eggs between the 8 th and 11th day gives a hatchability similar to that of unturned eggs. New evidence is presented that absence of turning leads to abnormal adhesion between the chorion and shell membranes. The mechanism by which turning effects development is discussed.
Embryological Development of Primordial Germ-cells in the Mouse: Influence of a New Mutation, Wj
Authors: Mintz Beatrice 
Published: April 2021

ABSTRACT
Twenty-seven mouse embryos at days from matings of Wjw × Wjw were examined in order to establish the embryological basis of the germ-cell deficiency found in the WjWj genotype at birth. Elective staining of primordial germ-cells was obtained with the azo dye coupling histochemical technique for alkaline phosphatase. Numbers and locations of these cells were recorded in complete serial sections. Formation of germ-cells occurs, as in normals, in all members of the 8-day group. At 9 days and later, during gonial migration from yolk sac toward germinal ridges, two distinct populations of individuals are recognizable. In one, the number of germ-cells increases; in the other, totals remain very low. The latter would be expected to characterize the WjWj class. Observed incidence of such cases was close to the theoretical frequency of 25 per cent, defective offspring. These findings support the earlier proof (Mintz & Russell, 1955, 1957) that the cells observed are the primordial germ-cells and are of extra-gonadal origin. In defectives, migratory retardation of germ-cells accompanies their mitotic insufficiency. The effects of Wj are compared with those of the alleles W and Wv, and the significance of the study for the problem of pleiotropic gene action is considered.
Evidence for a positional memory in the development of the chick wing bud
Authors: Smith J. C. 
Published: April 2021

ABSTRACTGrafts of quail zones of polarizing activity (ZPA), treated with 10000 rad γ-radiation, tend to remain at the base of a limb. Their signalling ability is not passed on to more distal tissue, but the limb goes on to produce a reduplication. This suggests that the effect of a ZPA can be remembered in its absence, and explains why a normal limb can develop if its ZPA is removed.
Development of the chick embryo mesoblast: pronephros, lateral plate, and early vasculature
Authors: Meier Stephen 
Published: April 2021

ABSTRACT
The early development of the mesoblast in the intermediate and lateral regions of the chick embryo was examined with the scanning and transmission electron microscope. It was found that primary mesenchyme here becomes condensed into epithelial structures that emerge in a metameric pattern. Viewed in developmental sequence, the intermediate mesoblast condenses into a narrowing cord of axially oriented cells which divert medially at regular intervals into the intersegmental interfaces of somitomeres and somites. These cells give rise to the vascular channels of the posterior cardinal vein as well as to tubular elements of the pronephros. Intermediate mesenchyme cells become epithelial, forming zonular junctional complexes apically and depositing patchy basal lamina over their basal surfaces. The lateral plate mesenchyme organizes similarly into somatic and splanchnic epithelial sheets that utilize the body coelom as their lumenal surface. Cells of the lateral plate extend filopodia basally that interweave with adjacent cells, fibrillar extracellular matrix, as well as with interstitial bodies. The pattern in the lateral plate is subtly ribbed as bands of mesoblast undulate along the axis. The central region of each band is raised while there are grooves created along lines of band abutment, corresponding to intersegmental clefts in the paraxial region and reflecting an underlying metameric pattern. These grooves are usually demarked medially by the protrusion of short segments of adjacent intermediate mesoblast. Most of the remaining primary mesenchyme develops into a non-metameric vascular epithelium, which forms a prominent anastamosing plexus between splanchnic mesoderm and endoderm. It is proposed that the emergence of primary mesenchyme into patterned epithelial anlage facilitates the distribution of neural crest cells introduced subsequently.
Nucleo-cytoplasmic interactions in cell hybrids between mouse oocytes, blastomeres and somatic cells
Authors: Tarkowski Andrzej K. , Bałakier Hanna 
Published: April 2021

ABSTRACT
With the help of the technique of Sendai virus-mediated cell fusion, hybrid cells were produced between two maturing oocytes, between maturing oocytes or mature secondary oocytes and interphase blastomeres from 2-cell embryos, and between secondary oocytes and follicle cells (FC). In the first case giant oocytes form and in these the two groups of condensing bivalents join on a common spindle, undergo a first meiotic division, and become arrested in metaphase II; these hybrids are heterozygous diploids. When blastomeres are fused with oocytes undergoing maturation, then the blastomere nucleus undergoes premature chromosome condensation (PCC), and two sets of chromosomes (meiotic and mitotic) come close to each other but the mitotic chromosomes are not fully incorporated into the meiotic spindle. The behaviour of the nuclei from blastomeres or from follicle cells fused with secondary ovulated oocytes, depends on whether or not the oocyte undergoes activation. When the oocyte is not activated, then the introduced nuclei undergo PCC but the chromosomes remain separate from the spindle of metaphase II. When the oocyte is activated, then the introduced nuclei remain in interphase; the FC nuclei may increase their volume eight times and undergo some other structural changes but during the 6 h period after fusion their appearance remains distinct from that of the female pronucleus. Since some oocytes are not activated after fusion has occurred, it follows that the fusion process itself is not sufficient to trigger egg activation.
Changes in the distribution of cortical myosin during the cellularization of the Drosophila embryo
Authors: Warn R. M. , Bullard B. , Magrath R. 
Published: April 2021

ABSTRACT
Changes in the distribution of myosin during the formation of the cellular blastoderm of Drosophila melanogaster were followed by staining sections of embryos with antibodies to myosin. These were visualized with indirect immunofluorescence. Prior to the start of cell membrane extension myosin is distributed between the nuclear caps as a thin sub-plasmalemma layer. There is also myosin present beneath the surface of the caps. When plasmalemma growth occurs, myosin is associated with the furrow canals, the tips of the advancing membranes. The fluorescence is distributed in an approximately hexagonal pattern around the growth points of each cell. The hexagons are joined up forming a network. It is suggested that this myosin is associated with bundles of microfilaments, orientated parallel to the surface, to form many interlocking contractile rings. The simultaneous contraction of these rings causes the cleavage of the blastoderm. During the first phase of membrane growth, myosin is also associated with the apical surfaces of the forming cells. At this stage these surfaces are rich in microvilli. However, by the time the furrow canals have reached the bases of the cells much of this myosin has disappeared. At about this time the apical surface becomes taut with a loss of the microvilli.
Changes in cell dimensions and intercellular contacts during cleavage-stage cell cycles in mouse embryonic cells
Authors: Lehtonen E. 
Published: April 2021

ABSTRACT
The cleavage behaviour of cells isolated from 1- to 8-cell-stage mouse embryos was studied with time-lapse video equipment; changes in cellular dimensions and their timing were recorded. The division of an isolated cell results in the formation of a twin-cell pair. The divisions of these two cells were always asynchronous. In each division the volume of a daughter cell was approximately half of that of the parental cell but its apparent surface area was 59–65 % of that of the parental cell. Consequently, the ratio of apparent surface area to volume increased in each division by 25–30%. The most noticeable changes were observed in the relationship between the two daughter cells of each division. After cytokinesis, the intercellular contact area gradually increased during the following cell cycle in the 2/8- and 2/16-cell pairs, whereas it hardly changed in the 2/2- and 2/4-cell pairs. The comparison of the behaviour of the daughter cells on different substrates suggested that the zona pellucida and the mid body might have a role in the contact development at the early stages. Scanning electron microscopy was used for studying changes in the density of cell surface microvilli in an attempt to explain how the cells regulate their intercellular contacts.
The in vitro culture of primitive-streak-stage mouse embryos
Authors: Tam P. P. L. , Snow M. H. L. 
Published: April 2021

ABSTRACT
The in vitro growth and morphogenesis of mouse embryos from early primitive-streak stage to early-somite stage is described. The embryo culture method employs a static culture system, a conventional chemically defined medium (Dulbecco’s modified Eagle’s medium), supplemented with additional glucose, glutamine and suitably prepared serum. The method of serum preparation is important for successful culture. Both mouse serum and rat serum support good development of primitive-streak-stage mouse embryos. Over 60% of early-streak stage and about 90 % of late-streak stage grow and develop for 48 h in vitro. During the first 24 h in culture, total growth of the embryos, as reflected by protein content, size and morphology is the same as in vivo.
The Localization of β-Glucuronidase in the Early Chick Embryo
Authors: Billett F. , Mulherkar Leela 
Published: April 2021

ABSTRACT
The technique for the localization of β-glucuronidase, based on the precipitation of ferric 8-hydroxyquinoline from quinolyl-8-glucuronide has been applied to explanted chick embryos. When the enzyme is first detectable, at the head-process stage, it appears to be widely diffused in the dorsal side of the embryo and in the adjacent area opaca. In later stages the histochemical reaction is confined to the region of the developing somites and neural tube.