bluuebunny/crossref_metadata_2025_split huggingface dataset:
Starch gel electrophoresis of the multiple haemo-globins of small and large larval Chironomus— a developmental haemoglobin sequence in an invertebrate
Authors: Manwell Clyde 
Published: April 2021

ABSTRACT
Small larvae (1-4 mg each) of Chironomus plumosus, whether surveyed in pooled samples or individually, have eight different haemoglobins in the haemolymph. Large larvae (8-11 mg each) of this species have ten different haemoglobins. Seven of the haemoglobins are unchanged throughout larval development. However, small larvae lack two of the major and one of the minor haemoglobins found in all large larvae; furthermore, a unique major haemo-globin of small larvae occurs only in traces in large larvae. The heterogeneity and the ontogenetic differences in Chironomus haemo-globin persist whether the haemoglobin is studied as oxyhaemoglobin, carbon-monoxyhaemoglobin, methaemoglobin or methaemoglobin cyanide, although the electrophoretic mobilities of some of the haemoglobin components are shifted by combination with different ligands and, especially, by oxidation to methaemoglobin. The heterogeneity and the ontogenetic differences are not altered by treatment of the haemoglobin with —SH and —S—S— reagents, nor by conversion of haemoglobin to globin by splitting off the haem with acid-acetone. Electrophoresis of globins prepared from each of the isolated major and minor Chironomus haemoglobins suggests that, in contrast to typical vertebrate haemoglobins, there is only a single polypeptide chain type in each of the multiple Chironomus haemoglobins. However, each of the multiple haemo-globins probably has a unique haemoglobin chain type, suggesting that each Chironomus haemoglobin component is coded from a different gene. Thus the insect Chironomus resembles the human in possessing an onto-genetic haemoglobin sequence involving both constant expression of some haemoglobin genes and modulation of the activity of others. As, in contrast to the human, Chironomus possesses giant chromosomes in many of its tissues, this discovery of an ontogenetic sequence to the major soluble protein present in larval Chironomus presents an attractive system for studying the interrelations between protein phenotype and the nuclear genotype during development.
Congenital eye defects in rats following maternal folic-acid deficiency during pregnancy
Authors: Armstrong R. Christy , Monie I. W. 
Published: April 2021

ABSTRACT
Malformations of fetal rat eyes result from a variety of maternal vitamin deficiencies employed either transiently or continuously during pregnancy. Thus, eye defects have been produced in rat fetuses as a result of maternal deficiencies of vitamin A (Wilson, Jordan & Brent, 1953), pantothenic acid (Lefebvres-Boisselot, 1951; Nelson, Asling & Evans, 1957), niacin (Chamberlain & Nelson, 1963) and pteroylglutamic acid (PGA or folic acid) (Evans, Nelson & Asling, 1951; Nelson, Asling & Evans, 1952; Giroud & Boisselot, 1951; Giroud, Lefebvres & Dupuis, 1952; Giroud, Delmas, Lefebvres & Prost, 1954).
Previous studies on the teratogenic effects of PGA-deficiency on the developing rat eye, although informative, have been concerned mainly with stages after the 15th day of pregnancy (the day of finding sperm in the vagina is considered to be day zero). However, since the eye begins forming between the 9th and 10th days of gestation, it was felt that a study embracing both early and late stages of ocular development in rat embryos from mothers maintained on a PGA-deficient regimen for different lengths of time during gestation would be of more value in understanding the genesis of certain ocular abnormalities. The following account concerns such an investigation and describes the abnormalities en-countered in the visual system.
Etude de 1’origine, de la migration et de la multiplication des cellules germinales chez l’embryon de lapin
Authors: Chretien Par Fr. Ch. 
Published: April 2021

ABSTRACT
La découverte par Waldeyer (1870) des cellules sexuelles ou ‘Ureier’ dans l’épithélium germinatif péritonéal d’embryons de poulet de 3 et 4 jours, ouvrit la voie à toute une série de travaux sur l’origine et la filiation des cellules germinales chez les Vertébrés.
The differentiation of epidermis II. Alternative pathways of differentiation of embryonic chicken epidermis in organ culture
Authors: Dodson J. W. 
Published: April 2021

ABSTRACT
Two series of experiments were made to determine the possible alteration of paths of differentiation of the epidermis from the metatarsal region of 12-day chicken embryos. The epidermis, separated from dermis after Versene treatment of the skin, either was cultivated in isolation for various periods, then recombined with dermis and cultivated further (series 1), or was placed on gels of collagen and grown in culture in the presence of excess of vitamin A (series 2). All explants were examined histologically. When epidermis isolated for 24 h was recombined with dermis, the upper cells degenerated as though still in isolation, but the basal cells, although they had become flattened while isolated, regenerated a viable, keratinizing epidermis; this ability was lost after 30–36 h of isolation. A basement membrane was re-formed against epidermis, following recombination, after isolation for 36–42 h. Thus the basal cells of isolated epidermis can survive for several hours in the absence of a basement membrane; the changes that they undergo are reversible for 24–30 h, but there is then a gradual loss of their potentialities. Epidermis grown on collagen gels on control medium formed a stratum corneum, but in the presence of excess of vitamin A no keratin appeared, the epithelium became thin, and mucous cells developed. The effect resembled that on epidermis of whole skin. The results demonstrate that the effect of the vitamin on the epidermis is direct and is not mediated by the dermis.
The effect of 3-acetylpyridine on the explanted chick embryo
Authors: Buckingham B. J. , Herrmann Heinz 
Published: April 2021

ABSTRACT
A structural analogue of nicotinic acid, 3-acetylpyridine, has been shown to produce morphological and physiological abnormalities in a variety of organisms. The effect of 3-acetylpyridine (AP) on chick embryos has been studied by several investigators using the technique of yolk-sac injection (Ackermann & Taylor, 1948; Zwilling & DeBell, 1950; Landauer, 1957; Herrmann, Clark & Landauer, 1963). Following AP treatment at 96 h of incubation, a reduction in body size, underdevelopment of leg musculature and edema were noted. Teratogenic effects of AP when administered after 24 h of incubation were much more diffuse and included instances of cerebral hernia and muscular hypoplasia (Landauer, 1957). Simultaneous injection of nicotinamide (Ackermann & Taylor, 1948; Landauer, 1957) decreased the incidence and severity of these conditions.
Studies on an embryonic lethal hybrid inDrosophila
Authors: Kinsey Janice D. 
Published: April 2021

ABSTRACTThe problems of nucleocytoplasmic interactions are of central importance in development and genetics. Studies of such interactions may help elucidate the mechanisms of differentiation of cells receiving the same genetic complement. One approach to a study of nucleocytoplasmic interactions is by examination of the development of interspecific hybrids, particularly those in which either syngamy fails to occur, or an abnormal development is produced.
The effect of 2,4-dinitrophenol on the development of early chick embryos
Authors: Bowman Patricia 
Published: April 2021

ABSTRACT
The effect of 2,4-dinitrophenol, an uncoupler of oxidative phosphorylation, has been studied on the chick embryo developing in vitro. 2,4-dinitrophenol in concentrations ranging between 10−4 M and 2 x 10−3 M causes a syndrome of abnormalities, the main features of which are degeneration and sometimes complete absence of neural tissue accompanied by reduction in number of and inhibition of the somites. Heart, notochord and blood islands are unaffected. A comparison is drawn between the effects of 2,4-dinitrophenol and other substances which affect the development of neural tissue and somites in explanted chick embryos.
The control of cell number in the lumbar spinal ganglia during the development ofXenopus laevistadpoles
Authors: Prestige M. C. 
Published: April 2021

ABSTRACTIt is the purpose of this paper to describe the development of the lumbar dorsal root ganglia after amputation of the leg. This operation can be performed at a very early stage before any connexions between the limb and the central nervous system are established. Alternatively, it can be performed at a number of later stages after the limb has been innervated. The extent of interaction can then be investigated for each stage by observing the subsequent development of the ganglia and comparing it with that of normal animals.
Cinemicrographic observations on the trophoblast and zona pellucida of the mouse blastocyst
Authors: Cole R. J. 
Published: April 2021

ABSTRACTThe behaviour of mouse blastocysts during penetration and shedding of the zona pellucida was studied in vitro by time lapse cinemicrography. Blastocysts obtained by super-ovulation were filmed in Waymouth’s medium MB 725/1 in a specially designed disposable plastic chamber with a gas space buffered to maintain 5 % CO 2 in air. Mouse blastocysts undergo cycles of rapid contraction (4–5 min) followed by slower re-expansion (2–3 h), both before and after penetration of the zona. The zona also exhibits slight elasticity unless excessively stretched. The initial penetration of the zona was followed in detail and appears to be the result of specific cellular activity, not non-specific herniation due to increasing blastocoelic pressure. Rotation of the blastocyst was also observed.
Cell proliferation and morphological patterns in the hydroidsTubulariaandHydractinia
Authors: Campbell Richard D. 
Published: April 2021

ABSTRACTMitotic figure distributions in the hydroids Tubularia and Hydractinia are related to both the axial and radial morphological organizations of the polyps. Cells divide in all regions of the body except at some extremities, but the abundance of dividing cells varies along the polyp axis. For example, in Hydractinia gonozooids mitotic figures are concentrated in the constricted part of the column, and in the Tubularia hydranth they are most abundant just above the whorl of gonophores. The polyps of both species of hydroids have a similar radial organization. In the distal hydranth portions this is manifested both in the positions of tentacles and in the positions of longitudinal gastrodermal ridges called taeniolae. Taeniolae generally are spaced between tentacles. In Tubularia and in Hydractinia gastrozooids, mitotic digestive cells are radially localized between taeniolae, that is, along the tentacular radii. The taeniolate organization appears to be a fundamental one in view of its wide phyletic distribution and its relation to other morphological and mitotic patterns. The similarity in mitotic patterns among different polyps is consistent with wide homologies existing between the structures of diverse hydroid types.
Recherches sur l’inhibition de la régénération du pharynx chez les planaires
Authors: Ziller-Sengel Par Catherine 
Published: April 2021

ABSTRACTDes expériences effectuées dans un travail antérieur (Ziller-Sengel, 1967) ont montré qu’il existe dans la région pharyngienne des planaires un facteur autoinhibiteur, capable d’empêcher la formation d’un pharynx si un pharynx est déjà présent. Cette inhibition est due à l’activité d’une substance spécifique diffusible, localisée dans la région pharyngienne. La substance inhibitrice de la formation du pharynx n’est décelée ni dans des extraits de têtes, ni dans des extraits de queues, ni dans des extraits de pharynx. C’est cette substance qui, au cours de la régénération normale du pharynx, empêcherait la formation simultanée de plusieurs pharynx (Wolff, 1962; Wolff, Lender & Ziller-Sengel, 1964; Ziller-Sengel, 1965).
Observations on congenital teratology in turkey embryos and its experimental transmission via transplantation
Authors: Tahara Yutaka , Kosin I. L. 
Published: April 2021

ABSTRACT
The embryonic period of the domestic turkey is characterized by a relatively high level of mortality (Kosin & Mun, 1960, 1965). The aim of the investigation reported below was to analyse the significance of certain changes observed in turkey embryos doomed to die because of either congenital or experimentally induced defects.
Tératologie expérimentale chez un Opilion (Arachnide)
Authors: Juberthie Par Christian 
Published: April 2021

ABSTRACTDans le grand ensemble des Arthropodes de nombreux morphologistes ont signalé, décrit et figuré un nombre élevé de cas tératologiques. Ces descriptions sont le plus souvent relatives à des cas isolés dont l’étude serait rendue longue et difficile si Balazuc n’avait groupé en des revues critiques les malformations décrites chez les Coléoptères (1948), les Hémiptères (1951), les Orthoptéroïdes (1955), les Hyménoptéroïdes (1958) et les Myriapodes (Balazuc & Schubart, 1962). Il reste, cependant, beaucoup à faire dans cette branche descriptive de la tératologie, et en particulier chez les Opilions où quelques animaux monstrueux seulement ont été décrits, ainsi que je l’ai signalé (Juberthie, 1963a, b).
A radioautographic study of the development of the somite in the chick embryo
Authors: Langman Jan , Nelson George R. 
Published: April 2021

ABSTRACT
Chick embryos ranging in age from 24 to 72 h were treated with 3H-thymidine to examine proliferation, formation and differentiation of the various somite components. The embryos were fixed 1 – 10 h after treatment, sectioned at 4 μ and processed for radioautography. The following observations were made:
Before the formation of the paraxial mesoderm, the DNA-synthesizing mesoderm cells are randomly distributed throughout the tissue. When the paraxial mesoderm cells become arranged in epithelial fashion, DNA synthesis occurs predominantly in the nuclei at the periphery of the epithelium, while the unlabeled nuclei and the mitotic figures are adjacent to the central space. Since 3 h after labeling the mitotic figures are labeled and 5 h later the labeled nuclei are again at the periphery, it is concluded that the nuclei in the walls of the somite undergo interkinetic migration. The cells formed by the ventral and major portion of the medial somite walls are deposited in the central cavity of the somite, where they lose their epithelial shape and become mesenchyme-like. They rarely synthesize DNA. With further increase in the number of the cells in the center of the somite, the ventral and medial walls lose their epithelial continuity and blend with the centrally located cells. Together they form a loosely woven tissue, referred to as the sclerotome. After formation of the sclerotome, the dorsal somite wall, now referred to as the dermatome, is the main source of a layer of cells with pale nuclei and darkly stained nucleoli. This layer, which is directly in contact with the inner surface of the dermatome, is referred to as the myotome. DNA synthesis is never observed in the cells of this layer. After the myotome has extended in a ventro-lateral direction to the coelomic cavity, the dermatome, with the exception of its most dorsal portion, loses its epithelial structure and the cells begin to form the dermis.
The antigenic structure of tumour cells as material for a study of tissue differentiation
Authors: Olenov J. M. , Fel V. JA. 
Published: April 2021

ABSTRACT
In the course of differentiation, in the overwhelming majority of cases, the cell genotype remains unchanged. However, tissue differences are inherited during cell reproduction (histiotypic growth). This means that the effects of determining influences are as a rule totally or almost totally irreversible, and hence only de-differentiation and not de-determination can take place. There is no return to a state from which different ways of development may be chosen.
Fine structure of egg envelopes and the activation changes of cortical alveoli in the river lamprey, Lampetra fluviatilis
Authors: Afzelius Björn A. , Nicander Lennart , Sjödén Inger 
Published: April 2021

ABSTRACT
Most eggs are surrounded by several prominent envelopes which have been given names depending on their origin, structure or chemical composition. As our present knowledge of these envelopes is very fragmentary, the results of attempts to homologize the different layers between different animal groups are still open to debate. The nomenclature in this field is quite confusing.
The relative rates of synthesis of DNA, sRNA and rRNA in the endodermal region and other parts of Xenopus laevis embryos
Authors: Woodland H. R. , Gurdon J. B. 
Published: April 2021

ABSTRACT
The onset and rates of synthesis of the major classes of nucleic acids have been extensively studied during the development of whole frog embryos (reviews by Brown, 1965; Gurdon, 1967 a). Such information is of interest because nucleic acids are the immediate products of genes, and their rates of synthesis therefore provide a direct measure of changes in gene activity. To date nucleic acid syn-thesis in parts of frog embryos has been analysed mainly by methods which do not distinguish different classes of RNA (e.g. Bachvarova & Davidson, 1966; Flickinger, Miyagi, Moser & Rollins, 1967). Since embryos consist of many different cell types, it is important to know to what extent the pattern of nucleic acid synthesis observed in the whole embryo is true for its individual regions, and in particular for one differentiating cell type. Any differences between parts of early embryos in respect of nucleic acid synthesis are of further interest, since they are likely to be related to unequally distributed components of the egg cytoplasm. Such a relationship may eventually lead to the identification of cytoplasmic components which regulate the activity of genes during cell differentiation.
Nouvelles recherches expérimentales sur les origines de la lignée reproductrice chez la Grenouille rousse
Authors: Bounoure Louis , Aubry Régine , Huck Marie-Louise 
Published: April 2021

ABSTRACT
Aussi simple, aussi facile à réaliser qu’il soit, aussi clairement qu’il semble parler dans un sens univoque, il n’est point de fait expérimental qui ne prête à controverse au nom de certaines vues théoriques discordantes, ou qui n’appelle des recherches complémentaires, soit quant aux moyens d’en mieux assurer le résultat, soit quant aux conséquences et aux enseignements qui peuvent sortir de sa réalisation imparfaite.
Présentation d’un appareil destiné à faire à de jeunes embryons d’oiseaux de petites injections localisées de substances chimiques
Authors: Ancel P. , Houget J. 
Published: April 2021

ABSTRACT
Les injections de substances chimiques au cours des premiers jours de l’incubation en vue d’obtenir des malformations d’embryons d’oiseaux ont été faites suivant les auteurs dans le blanc, le jaune ou la chambre à air de l’œuf, tandis que d’autres déposaient sur l’embryon une goutte de la solution à étudier. Dans le but de faciliter l’étude de certains problèmes de tératogénèse, nous avons mis au point une autre technique permettant de réaliser des injections localisées à des ébauches embryonnaires déterminées et fait construire un appareil dont nous allons donner la description et le mode de fonctionnement.
The development of teratomas from intratesticular grafts of tubal mouse eggs
Authors: Stevens Leroy C. 
Published: April 2021

ABSTRACT
Grafts of cleaving tubal ova from non-inbred mice to ectopic sites usually result in growths composed of extra-embryonic but not embryonic tissues (Fawcett, Wisloki & Waldo, 1947; Fawcett, 1950; Jones, 1951; Whitten 1958; Kirby, 1960, 1962a; Billington, 1965; and others). Runner (1947) grafted tubal mouse ova to the anterior chamber of the eye and one developed the three primary germ layers and then regressed, probably because the host and donor were histo-incompatible. This is the only report of an ectopically grafted pre-uterine egg that developed intra-embryonic derivatives. Kirby (1962b, 1965) grafted oviducal segmenting mouse eggs to the kidney and obtained only tropho-blast and extra-embryonic membranes. He concluded that a ‘uterine factor’ is necessary for the development of intra-embryonic structures from mouse eggs. Kirby (1965) and Billington (1965) grafted moruiae and blastocysts to the testis, and the morulae never gave rise to embryonic shield derivatives.
Etude expérimentale de la morphogenèse de la cage thoracique chez Fembryon de Poulet: mécanismes et origine du matériel
Authors: Pinot Madeleine 
Published: April 2021

ABSTRACT
An experimental study of the morphogenesis of the thoracic cage of the chick embryo: mechanisms and origins
In the chick embryo, the ribs develop at the level extending from somite 19 to somite 26. According to several investigations, only the dorsal third of the body wall originates from the somitic mesenchyme, whereas more recent works have shown that the whole costal and intercostal material is of somitic origin. In the present paper, the origin of the material that forms the body wall as well as the mechanisms of thoracic morphogenesis have been studied.
The evolution of somites 21-22 to 25, grafted into the coelome of a host embryo under different experimental conditions, and the morphogenesis of the thorax after radiodestruction of the same somitic level at different stages have been examined.
The results have shown that:
The whole costal and intercostal material and the abdominal musculature originate from the somitic mesenchyme, whereas the sternum and the associated pectoral musculature originate from the lateral plate. The morphogenesis of the ribs and the intercostal muscles do not depend upon the lateral plate, nor upon the neural tube and notochord. Ribs and intercostal muscles are formed by a lateral outgrowth of somitic mesenchyme. The morphogenesis of the sternum along with the associated pectoral muscles and the organogenesis of the thoracic dorsal region are completely independent. The lateral outgrowth of the somitic mesenchyme that forms the thoracic ribs and the corresponding intercostal muscles starts antero-posteriorly in embryos which have reached the 22-27 somite stages.
Nucleic acid and protein synthesis and pattern regulation in hydra: I. Regional patterns of synthesis and changes in synthesis during hypostome formation
Authors: Clarkson S. G. 
Published: April 2021

ABSTRACT
Hydra provides a convenient system for the study of the regulation of a linear pattern of organization. Almost any region is capable of being reconstituted into the whole organism and regulation is always polarized, i.e. distal structures (hypostome and tentacles) are formed from distal ends and proximal structures (peduncle and basal disk) from proximal ends.
Ultrastructural changes in the avian vitelline membrane during embryonic development
Authors: Jensen Cynthia 
Published: April 2021

ABSTRACT
The vitelline (yolk) membrane of the avian egg plays a dual role during early embryonic development; it encloses the yolk and provides a substratum for expansion of the embryo (Fig. 1). Expansion appears to be dependent upon the movement of cells at the edge of the blastoderm which is intimately associated with the inner layer of the vitelline membrane (New, 1959; Bellairs, 1963). The blastoderm (embryonic plus extraembryonic cells) has almost covered the entire surface of the yolk by the third and fourth days of incubation, and when this stage has been reached the vitelline membrane ruptures over the embryo and slips toward the vegetal pole.