bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cultivation of post-implantation mouse and rat embryos on plasma clots
Authors: New D. A. T. , Stein K. F. 
Published: April 2021

ABSTRACT
Mouse and rat embryos of primitive streak to early somite stages have been grown on clots of plasma and embryo extract. Of nineteen mouse embryos explanted at 8–12 somites, seventeen acquired a blood circulation and thirteen developed to limb bud stages with 24–32 somites. Of the mouse embryos explanted at 1–7 somites, 72 per cent, developed a blood circulation and 33 per cent, went on to limb bud stages. Of the mouse embryos explanted at head fold and head process stages, 60 per cent, developed over 8 somites and 26 per cent, a blood circulation. Mouse embryos explanted at primitive streak stages developed neural folds and a few somites, but not a blood circulation. Twenty-two rat embryos explanted at 6–12 somites acquired anterior limb buds and 25–30 somites. Eighty-five rat embryos explanted at head process or head fold stages mostly became 6–12 somite embryos with beating hearts. Only four formed a blood circulation. The rate of development in vitro, at least for the first 24 hr., was about the same as in vivo. The maximum amount of development obtained in vitro was equivalent to about 40 hr. in vivo. Often the blood continued to circulate for over 48 hr., and the heart to heat for over 72 hr. Addition of 4-5 per cent. CO2 to the air in the culture vessels was found to be beneficial. Increasing the O2 to 60 per cent, improved the development of the older, but not of the younger embryos. It appeared immaterial whether the embryo extract used in the culture media was obtained from chick or mouse.
Isolement expérimental du mésenchyme propre du foie et rôle morphogène de la composante mésodermique dans l’organogenèse hépatique
Authors: Douarin par Nicole Le 
Published: April 2021

ABSTRACT
L’organogenèse du foie chez les Oiseaux a été décrite par de nombreux auteurs. La première ébauche hépatique visible apparait chez l’embryon de Poulet au stade de 20 à 22 somites sous forme d’une évagination endodermique au niveau de la lèvre antérieure de l’ombilic intestinal (Brouha, 1898; Choronschitzky, 1900; Hildebrandt, 1902). Cette ébauche primaire émet bientôt un premier diverticule crânial, puis un autre caudal, qui constituent les bourgeons hépatiques secondaires. Par rapport au sinus veineux, le diverticule crânial est dorsal tandis que le diverticule caudal est ventral; ils sont décrits à ce stade par Felix (1892) et Hammar (1893) en particulier. Très rapidement, ces bourgeons s’étendent vers l’avant dans le mésentère ventral correspondant au septum transversum, et constituent pendant le 3ème et le 4ème jour de l’incubation un cylindre de tissu hépatique entourant le ductus venosus. La prolifération des trabécules hépatiques est accompagnée par la formation de capillaires issus du ductus venosus comme l’ont décrit Shore (1891), Hammar (1893) et Minot (1900). Ensuite, les lobes droit et gauche du foie s’accroissent vers l’arrière dans la cavité abdominale.
A study of carbohydrate metabolism in Planorbis exustus
Authors: Sherbet Gajanan V. , Lakshmi M. S. 
Published: April 2021

ABSTRACT
The metabolism of Planorbis exustus has been studied using sodium azide and iodoacetamide (IAA) at different concentrations. Azide (0 · 001,0 · 002 and 0 ·003 M) treated cleavage-stage embryos developed normally till they reached gastrulation when their development was arrested. Gastrulae stopped all morphogenetic activities. This was generally followed by hydropia. No exogastrulation was caused. The 48-, 60- and 72-hr.-old embryos showed delay in development, Vesiculation and shell abnormalities or underwent a block in development. Treatment with IAA caused arrest of development, rounding off and slight enlargement of the blastomeres. The development of this molluscan species seems to be divisible into pre-gastrulation and post-gastrulation (including gastrulation) phases. In the pre-gastrulation phase, a metabolism involving other substrates than a carbohydrate is dominant. The energy requirement of cleavage, which conceivably forms a small fraction of the total requirement of the embryo, is met by carbohydrate metabolism. The importance of the latter for morphogenetic activities is evidenced by the vulnerability of these stages to azide. The carbohydrate metabolism is also important for the processes of differentiation and growth.
Yolk utilization in the notochord of newt as studied by electron microscopy
Authors: Jurand A. , Selman G. G. 
Published: April 2021

ABSTRACT
An electron microscope study has been made of the ultrastructure of the yolk platelets in notochord cells of Triturus alpestris during the larval stages when the yolk is utilized by the differentiating cells. The inner crystalline core of the platelet which at earlier stages occupies most of its volume, is progressively replaced during the process by an irregularly-ordered granular zone. This granular zone is bounded by an envelope consisting of multiple layers of lamellae. The lamellar zone is a special feature of yolk platelets in notochord during utilization.
The anlage of the cerebellar nuclei in chick after early extirpation of the vestibular region
Authors: Rüdeberg Sven-Ingvar 
Published: April 2021

ABSTRACT
An experimental investigation was made into the question of whether the deep cerebellar nuclei arise embryologically through a migration of cells from the vestibular nuclei, as has been suggested in several morphological papers dealing with different vertebrate species. In very young chick embryos (about days), the neural tube was extirpated from a point just caudal to the cerebellar anlage to a point level with the second pair of somites. Incubation of the eggs then continued until the age at which the anlage of the deep cerebellar nuclei becomes clearly visible in normal chick embryos. From an extensive material, comprising 109 serially sectioned embryos, a few stages are described. These embryos were selected according to the purity of the operation and the developmental stage of the embryo. A developmental series is thus described from HH 30-HH 36, in which stages the cerebellar nuclear anlage forms and differentiates into its different portions in normal chick embryos. Despite large gaps in the brain and lack of vestibular nuclei, the morphology of the cerebellum, as well as its nuclear anlagen, appears to be normal during the actual period. The conclusion reached is that the deep cerebellar nuclei in chick cannot, at least in their principal part, be considered to develop embryologically through a migration of cells from the vestibular nuclei.
Studies on embryonic determination of the harlequin-fly, Chironomus dorsalis. II. Effects of partial irradiation of the egg by ultra-violet light
Authors: yajima Hideo 
Published: April 2021

ABSTRACT
Irradiation by ultra-violet light of the egg mass as a whole and partial irradiation of single eggs were employed for the analysis of embryonic determination in the harlequin-fly, Chironomus dorsalis. Three kinds of abnormalities were obtained; i.e. double malformations, single larvae with defective parts, and undifferentiated or dead eggs. Relationships between the frequency of occurrence of double malformations and the duration of exposure and developmental stage of irradiation are as follows : For exposures lasting from 0·5 to 3 min., double cephalons—duplication of cephalic structures—were obtained most often by 1·5 min. exposure and double abdomens were produced most often by 2 · 5 min. exposure. The frequency of double malformations decreases gradually after nuclear migration. Up until 1 hr. after nuclear migration, malformations are still obtained in small numbers but at 4 hr. they are no longer obtained. After partial irradiation, double cephalon was caused by posterior irradiation and double abdomen by anterior irradiation. The topographic extent of the formative localities is discussed.
Phosphoprotéine-phosphatase et résorption du vitellus chez les amphibiens: une étude cyto-chimique, électrophorétique et immunologique
Authors: Denis par H. 
Published: April 2021

ABSTRACT
Les Cellules embryonnaires de la plupart des vertébrés sont caractérisées par la possession de réserves vitellines, dont la résorption accompagne et même conditionne, dans une certaine mesure, la morphogénèse. En effet, le vitellus constitue pour l’embryon le réservoir principal d’acides aminés, pièces de construction indispensables pour la synthèse protéique. La connaissance du mécanisme permettant aux tissus en différenciation de mobiliser leurs réserves d’acides aminés pour les intégrer dans de nouvelles protéines serait fort utile à notre compréhension de la morphogénèse. Deux enzymes ou groupes d’enzymes ont été jusqu’ici rendus responsables de la résorption du vitellus chez les embryons d’amphibien : la phosphoprotéine-phosphatase (PPPase), d’une part, la cathepsine et diverses peptidases, d’autre part. Chaque type d’enzyme aurait un röle bien défini dans la dégradation des réserves vitellines. La PPPase produirait une déphosphorylation du vitellus, grâce à laquelle celui-ci pourrait passer en solution. Les enzymes protéolytiques et peptidasiques scinderaient les protéines solubilisées en chaînes polypeptidiques de plus en plus courtes jusqu’au stade acide aminé. Ce schéma de la résorption du vitellus est basé principalement sur les travaux de Harris (1946), Gross (1952), Mezger-Freed (1953), Barth et Barth (1951, 1954), Flickinger (1956), Nass (1962) et Urbani (1955, 1957).
Transplantation antigens in the mouse embryo. The fate of early embryo tissues transplanted to adult hosts
Authors: Edidin Michael 
Published: April 2021

ABSTRACT
The Evidence for and against the presence in cells of embryo and foetal mice of transplantation antigens, the cell-bound substances provoking the rejection of allogeneic tissue homografts, rests on two classes of experiments: those relying upon serological techniques for the detection of the antigens, and those involving some test of transplantation antigen activity in intact animals. Experiments of the former class have indicated that there are no histocompatibility antigens present on the cells of most newborn or late foetal mice, but that these antigens quickly appear during the first 2 days of neo-natal life, rendering cells liable to agglutination or lysis (Pizarro, Hoecker, Rubenstein & Ramus, 1961; Moller, 1961 a, 1961b). However, Moller (1961a) was able to show that cells of newborn mice resistant to cytotoxic isoantisera did absorb the antibodies of these sera, suggesting that the tissues of newborn mice contain transplantation antigens, but that these antigens are not present on cells in sufficient numbers to make them susceptible to agglutination or lysis. This suggestion was borne out by later experiments (Moller, 1963) in which transplantation antigens were demonstrated in 13-day embryos by injecting lethally irradiated liver cells of these embryos into allogeneic adults and measuring the injected animals’ production of humoral antibodies against the grafted tissues.
The influence of lithium on the competence of the ectoderm in Ambystoma mexicanum
Authors: Gebhardt D. O. E. , Nieuwkoop P. D. 
Published: April 2021

ABSTRACT
Ectodermal sandwiches of Ambystoma mexicanum of stage (Harrison) containing anterior notochord as inductor were treated with a 0·05 M LiCl solution for 24 hr. It was found that lithium was capable of changing the neural induction pattern of these explants by increasing the number of rhombencephalic and spino-cordal inductions and decreasing the number of prosencephalic ones. Sandwiches made from ectoderm of various developmental stages (stages 8 –12) and not containing an inductor were treated with the lithium solution for 2- or 24-hr. periods. In the explants made with ectoderm of stage 8, stage 9 or stage a very characteristic type of cell displacement occurred which resembled the phenomenon of exogastrulation. The ectoderm of the younger stages was shown to be mesodermalized and entodermalized to a considerable extent by the treatment. The period of mesodermal competence of the ectoderm, as judged by its reactivity towards lithium, extends from stage 8 (or earlier) up to stage (Harrison). The different periods of primary competence for (a) meso- and ento-dermalization, and (b) activation (neuralization) of the ectoderm are considered. Also the subsequently acquired competence for (c) transformation (caudalization) of the activated ectoderm into more caudal neural structures is discussed. The various periods of competence are presented in the form of a diagram together with the corresponding inductive stimuli.
Comportement en culture in vitro des ébauches dentaires de rongeurs prélevées aux stades de prédifférenciation
Authors: Pourtois par M. 
Published: April 2021

ABSTRACT
DÈs 1936, Glasstone a montré que des bourgeons dentaires de Mammifères, prélevés à des stades précoces, peuvent modeler in vitro toutes les cúspides et les sillons de la dent adulte, c’est à dire les détails caractéristiques de leur morphologie définitive.
The activity of hair follicles in parabiotic rats
Authors: Ebling F. J. , Hervey G. R. 
Published: April 2021

ABSTRACT
Hair growth in the rat occurs in a series of waves, which start ventrally and pass over the flanks to the back (Dry, 1926; Butcher, 1934; Johnson, 1958a). The activity of the hair follicle is cyclic; when the hair has been fully formed there is a period of quiescence during which the dead hair is retained as a ‘club’. The duration of the complete cycle varies with site and age, ranging from 24 to about 100 days (Ebling & Johnson, 1964).
Effets de Factinomycine D sur la morphogénèse et le métabolisme des acides nucléiques chez l’embryon de poulet
Authors: Heilporn-Pohl par V. 
Published: April 2021

ABSTRACT
On admet généralement que Factinomycine D bloque la synthèse de l’acide ribonucléique messager (m-RNA) en se combinant à l’acide désoxyribonucléique (DNA) (Reich, Goldberg et Rabinowitz, 1962; Shatkin, 1962) et en inhibant de ce fait la RNA polymérase.
A microscopic study of chlorpromazine (largactil) treated axolotl larvae
Authors: Eyal-Giladi H. , Eyal Z. , Eshel S. 
Published: April 2021

ABSTRACT
In previous publications (Eyal-Giladi & Eyal, 1962; Eyal & Eyal-Giladi, 1963) some of the macroscopic effects produced by chlorpromazine (CPZ) on the development and growth rate of Axolotl embryos have been reported. They include different abnormalities (microcephaly, defects in eyes, gills and pigmentation) depending on the CPZ concentration used and the length of the immersion period. In addition, larvae subjected to high CPZ concentrations and longer time of treatment proved, at the time of fixation, to be smaller than the controls, whereas larvae treated by low CPZ concentrations tended to grow bigger than the controls.
Transient embryonic antigens in the chick
Authors: McCallion D. J. , Trott J. C. 
Published: April 2021

ABSTRACT
Immunochemical analysis of the 9-day chick brain with 9-day brain antiserum reveals significant amounts of two different groups of antigens. One group consists of at least three antigens. The other group consists of at least two antigens. Comparison of 9-day brain with other 9-day organs and with adult organs, including adult brain, reveals that the group of three antigens are common antigens and that one of them is transient and disappears by hatching. It is further shown that of the group of two antigens at least one is neural-specific and transient and disappears from the brain by hatching.
The origin of the abnormalities of the inner ear in dreher mice
Authors: Deol M. S. 
Published: April 2021

ABSTRACTThe abnormalities of the inner ear in dreher mice may be viewed as the consequences of an incomplete or weak differentiation of the otic vesicle. As it is known from experimental work on other vertebrates that this differentiation depends on the inductive influence of the neural tube, it was thought that the neural tube might be abnormal in these animals. It was found that not only is the neural tube abnormal, but its abnormalities are seen at least one day before those of the inner ear. The relevance of these findings to mutants with defects of the eyes is discussed.
The effects of transection and extirpation on axis formation and elongation in the young mouse embryo
Authors: Smith Lois Jean 
Published: April 2021

ABSTRACTAn in vitro method is described whereby it is possible to perform transection and extirpation experiments on the young mouse embryo. Mouse embryos having 4 – 7 (rarely 8) somites at the beginning of culture were incubated for 18 – 20 hr. Intact embryos added 6 – 10 somites, the number depending on the number at the beginning of culture. Other systems, particularly gut and heart, showed even greater differentiation. The axial level at which they were transected determined the ways in which the transected embryos differed from the intact embryos. Notochord lengths in the cut embryos varied with the experiment but the base of the notochord was always present and at the same level. The neural folds closed or remained open depending on whether or not somitic mesoderm fused under them. Fusion of somitic mesoderm was affected by the presence or absence of notochord. The number of new somites formed, however, was unaffected by the experimental manipulations and all were found to come from cells located anterior to the node at the beginning of culture. Gut differentiation was unchanged. The results of all experiments were similar to those obtained from experiments in the chick.
Expression and function of Pax 1 during development of the pectoral girdle
Authors: Timmons Paula M. , Wallin Johan , Rigby Peter W. J. , Balling Rudi 
Published: April 2021

ABSTRACT
Pax 1 is a member of the paired-box containing gene family. Expression has previously been observed in the developing sclerotomes and later in the anlagen of the intervertebral discs. Analysis of Pax 1-deficient undulated mice revealed an important role for this gene in the development of the axial skeleton, in which Pax 1 apparently functions as a mediator of notochordal signals during sclerotome differentiation. Here we demonstrate that Pax 1 is also transiently expressed in the developing limb buds. A comparative phenotypic analysis of different undulated alleles shows that this expression is of functional significance. In mice that are mutant for the Pax 1 gene severe developmental abnormalities are found in the pectoral girdle. These include fusions of skeletal elements which would normally remain separate, and failures in the differentiation of blastemas into cartilaginous structures. Although Pax 1 is also expressed in the developing hindlimb buds and Wolffian ridge, no malformations could be detected in the corresponding regions of Pax 1 mutant mice. These findings show that, in addition to its role in the developing vertebral column, Pax 1 has an important function in the development of parts of the appendicular skeleton.
The ‘prespore-like cells’ of Dictyostelium have ceased to express a prespore gene: analysis using short-lived β-galactosidases as reporters
Authors: Detterbeck Susanne , Morandini Piero , Wetterauer Birgit , Bachmair Andreas , Fischer Karin , MacWilliams Harry K. 
Published: April 2021

ABSTRACT
In transgenic strains of Dictyostelium discoideum that express β-galactosidase under the control of a prespore-specific promoter, only early slugs show reporter confined to the prespore zone. As slugs migrate β-galactosidase-positive cells accumulate in the prestalk zone; ultimately, there may be so many that the prestalk-prespore boundary is no longer distinguishable (Harwood, A., Early, A., Jermyn, K. and Williams, J. (1991)Differentiation 46, 7-13). It is not clear whether these ‘anomalous’ reporter-positive cells currently express prespore genes; another possibility is that they are ex-prespore cells that have transformed to prestalk and sorted to the prestalk zone (Sternfeld, J. (1993) Roux Archiv. Dev. Biol. 201, 354-363), while retaining their previously produced reporter. To test the activity of the prespore genes in these cells, we have made prespore reporter constructs whose products decay quickly; these are based on constructs used to investigate protein turnover in yeast (Bachmair, A., Finley, D. and Varshavsky, A. (1986) Science 234, 179-186). In strains bearing such constructs, β-galactosidase-positive cells do not appear in the prestalk zone. The apparent deterioration of the prestalk/prespore pattern in older slugs is thus an artefact of reporter stability.
Fate mapping of the silkworm, Bombyx mori, using localized UV irradiation of the egg at fertilization
Authors: Myohara Maroko 
Published: April 2021

ABSTRACT
Bombyx eggs at the fertilization stage (0-2 hours after oviposition) were irradiated with a scanning UV-laser microbeam (355 nm) over an area of about 1% of the total egg surface. In spite of absence of nuclei or cells at the irradiated sites, larvae from treated eggs showed localized cuticle defects in the integument. The location and frequency of the defects within the cuticular pattern correlated closely to the site of irradiation both in the antero-posterior and the dorsoventral direction. Based on the correlation, presumptive regions for each larval segment were located and a fate map of the Bombyx egg was established.
MyoD expression marks the onset of skeletal myogenesis in Myf-5 mutant mice
Authors: Braun Thomas , Bober Eva , Rudnicki Michael A. , Jaenisch Rudolf , Arnold Hans-Henning 
Published: April 2021

ABSTRACT
The expression pattern of myogenic regulatory factors and myotome-specific contractile proteins was studied during embryonic development of Myf-5 mutant mice by in situ hybridization and immunohistochemistry.
In contrast to somites in wild-type embryos, no expression of myogenin and Myf-6 (MRF4), or any other myotomal markers was detected in mutant animals at E9.0 and E10.0 indicating that Myf-5 plays a crucial role during this developmental period. Significantly, the onset of MyoD expression in rostral somites of E10.5 embryos was unaffected by the Myf-5 mutation suggesting that the activation of the MyoD gene occurs independently of Myf-5 at the correct developmental time. Immediately after the activation of MyoD myogenin transcripts and protein accumulated within the myotome. The first contractile proteins of the sarcomeric apparatus appeared slightly later. By E11.5 the expression of muscle markers were indistinguishable between wild-type and Myf-5 mutant mice.
The migration of muscle precursor cells that leave the somites to form limb musculature was monitored in Myf-5-mutant mice by Pax-3 expression. Pax-3-positive cells were equally found in somites and limbs of E10.0 wild-type and mutant mice indicating that myogenic factor expression at the level of somites is not a prerequisite for determination and subsequent migration of limb precursor cells.