bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selectivity in regeneration of the oculomotor nerve in the cichlid fish, Astronotus ocellatus
Authors: Sperry R. W. , Arora H. L. 
Published: April 2021

ABSTRACT
It has long been considered a general rule for nerve regeneration that the reinnervation of skeletal muscle is nonselective. Regenerating nerve fibers are supposed to reconnect with one skeletal muscle as readily as another according to studies covering a wide range of vertebrates (Weiss, 1937; Weiss & Taylor, 1944; Weiss & Hoag, 1946; Bernstein & Guth, 1961; Guth, 1961, 1962, 1963). Similarly, in embryogenesis proper functional connexions between nerve centers and particular muscles are supposedly attained, not by selective nerve outgrowth but rather through a process of ‘myotypic modulation’ (Weiss, 1955) that presupposes nonselective peripheral innervation.
Influence de la puromycine sur la morphogenèse et la synthèse des macromolécules chez l’embryon de poulet
Authors: Malpoix Par P. , Limbosch S. 
Published: April 2021

ABSTRACT
L’inhibition des synthèses protéiques par la puromycine confère à cette substance un intérêt particulier pour l’étude précise du mécanisme de la synthèse d’une protéine spécifique au cours de la morphogenèse. Les études déjà effectuées dans notre laboratoire sur les effets de la puromycine chez les œufs de Batraciens et chez Acetabularia (Legros, 1965; Brachet, 1963; Brachet, Denis & De Vitry, 1964), ainsi que sur les racines d’oignons (Bosseler, Six & Simic, 1964) permettent de faire des comparaisons utiles.
The ovary and sexual maturation of the brain
Authors: Smith W. N. Adams 
Published: April 2021

ABSTRACT
Pfeiffer (1935, 1936) reported the induction of constant oestrus in female rats following the transplantation of testes from litter-mate males just after birth and noted that the ovaries of these animals did not contain corpora lutea. These changes remained after removal of the testis transplants. The same effects were obtained by Bradbury (1941) following the administration of multiple doses of testosterone propionate. Barraclough & Leathern (1954) found that a single injection of 1 mg of testosterone propionate at 5 days of age led to permanent sterility in female mice, with no corpus luteum formation in their ovaries. Similar results were obtained in rats by Barraclough (1961) with the administration of a single injection of 1·25 mg of testosterone propionate. This permanent change in ovarian function does not appear to be a direct effect upon the ovary (Bradbury, 1941). The masculinizing influence of testosterone propionate appears to be exerted upon the brain, with only an indirect effect upon the anterior pituitary gland by way of the hypothalamus (Adams Smith & Peng, 1966). The influence of the ovary in sexual differentiation of the central nervous system is not clear. This study was undertaken in an endeavour to determine the pattern of sexual maturation of the brain of the female rat ovariectomized at birth and treated with testosterone propionate at different times during the first three post-natal weeks. Different doses of testosterone were administered to see whether dosage influenced the receptive period of the animal’s brain. The receptive period found in ovariectomized animals would allow a comparison with results obtained by workers who had treated normal females with testosterone, so that an assessment could be made as to whether the presence of the ovary influenced the length of this receptive period. Control procedures were planned to allow an observation of the sexual maturation of the brain of ovariectomized females not subjected to androgen treatment.
The analysis of species specific variations in form and growth pattern in Hydra
Authors: Haynes Julian F. 
Published: April 2021

ABSTRACT
The ability of four different species of Hydra to oxidize succinate has been measured. Each species studied shows a gradient in the activity of succinic dehydrogenase, which appears to be identical to the metabolic gradients described by Child & Hyman. Each species may be recognized by its unique metabolic gradient. The relationship between the growth-regulating system proposed by Burnett for Hydra and the metabolic gradient is discussed. The control of the level of enzyme activity is shown to be by a pair of organismal factors which are also responsible for the maintenance of polarity in Hydra. By using the level of enzymic activity as a measure of the relative amounts of these two factors at any level in the animal, it is possible to explain the differences in form and metabolic gradient of the different species in terms of modifications in the relative amounts of the growth stimulator and inhibitor.
Effects of temperature on tadpole hearts in vitro
Authors: Stephenson Elsie M. 
Published: April 2021

ABSTRACT
Whole hearts of tadpoles of Limnodynastes peroni were cultured successfully in a combined avian-synthetic medium identical with that used for mammalian, avian and reptilian tissues. The extirpated hearts were cultured from 37 to 5°C. Temperature effects on organ viability and function and on cell outgrowth were studied comparatively. Although viability could be maintained for up to 6 days at 37°C, this temperature was ultimately lethal. From 30 to 5°C inclusive total viability or maintenance was the general rule. Rate of heart beat was at first accelerated at 37°C but dropped as moribund conditions developed. For the other temperatures used, though absolute values varied considerably, a more or less constant relative pattern emerged, with the optimal rate at 30°C and successive decreases occurring from 25 to 5°C. Cell migration did not occur at 37 or 5°C. The optimal temperature for outgrowth was 30°C, while progressively slower migration occurred from 25 to 15°C. At 8°C, outgrowth was confined to a few cells in a limited number of cultures. Although these results apply at present to only one species, the establishment of 30°C as an optimal incubation temperature may be important in view of the fact that almost all previous amphibian cultures have been grown at temperatures not exceeding 26°C and often considerably lower.
Reversible effect of chloroacetophenone by sulphydryl groups on morphogenesis of chick embryos
Authors: Mulherkar Leela , Joshi S. S. , Diwan B. A. , Joshi P. N. 
Published: April 2021

ABSTRACT
Chloroacetophenone (CAP), a specific inhibitor of SH groups, applied at 5 × 10−4 M for 15 min at the definitive primitive streak stage of chick embryos causes abnormalities, predominantly in the nervous system. The effects of CAP can be reversed by a subsequent treatment with thiomalic acid (5 × 10−4) or glutathione (1 × 10−5 M). Equimolar concentration of serine (4 × 10−4), which is structurally similar to cysteine except that SH of cysteine is replaced by OH in serine, fails to reverse the effects of CAP. The results of the present work suggest that the reversal of the CAP effects is brought about by SH groups.
Genotype and environment in the determination of minor skeletal variants and body weight in mice
Authors: Howe W. L. , Parsons P. A. 
Published: April 2021

ABSTRACT
Numerous minor skeletal variants have been described in the mouse (Grüneberg, 1963), other small mammals (Berry & Searle, 1963) and in man (Comas, 1960; Brothwell, 1963; Grüneberg, 1963). In genetically heterogeneous material such as man it is very difficult to sort out the factors causing these variants. However, in experimental animals such as the mouse the use of inbred strains and crosses derived from them permits a more detailed understanding of these factors, in particular the relative importance of heredity and environment. Grüneberg (1963) cites numerous references showing very great differences in the percentage incidence of many minor variants in mice between inbred strains and in some cases between hybrids. The conclusion is that much of this variation is genetic in origin. Even so, certain environmental factors have been shown to be of importance, such as maternal age, parity, maternal weight and maternal diet. Some of these environmental factors may be highly correlated, so that large amounts of data may be needed to determine the causative factor. For example, Kalter (1956) found a decrease in the incidence of median cleft palate, induced by injecting primigravid pregnant mice with cortisone, with increasing maternal age. However, from multiple regression analyses, he concluded that maternal weight was the most important factor. Maternal age seemed to play a role only because it is highly correlated with maternal weight (see also Parsons, 1964).
Ploidy,pigment patterns and species specific antigenicity in interspecific nuclear transplantations in newts
Authors: Sládeček F. , Romanovský A. 
Published: April 2021

ABSTRACT
It was shown by Simnett (1964) that in Xenopus laevis skin grafts in adult frogs between members of the same nuclear clone were tolerated in the same way as autografts, but in skin grafts made between individuals belonging to different nuclear clones a homograft rejection occurred. The nucleus is therefore responsible for the synthesis of specific transplantation antigens. It seemed to us useful to investigate the species-specific antigenicity of animals derived from eggs transplanted with foreign nuclei in correlation with their ploidy and with the development of their species-specific pigment patterns, as a proof of functional activity of transplanted nuclei. For this purpose we used two species of Trituras, T. vulgaris and T. alpestris, because of earlier studies carried out in our laboratory on the pigmentation of their hybrids (Romanovský & Štefanová, 1960; Mazáková-Štefanová, 1965) and on their species-specific antigenicity (Romanovský, 1962a, b), in spite of the known difficulties and limitations of nuclear transplantation experiments in these species (Lehman, 1955; Sládeček & Mazáková-Štefanová, 1964, 1965).
A regional change in the rigidity of the cortex of the egg of Rana nigromaculata following extrusion of the second polar body
Authors: Kubota T. 
Published: April 2021

ABSTRACT
Measurements of the consistency of the protoplasm by following the movement of cellular granules under centrifugal force have been made in various materials (e.g. for cytoplasm, Heilbrunn, 1928; Heilbrunn & Wilson, 1948; Allen, 1960; for cortex, Brown, 1934; Wilson, 1951; Zimmerman, Landau & Marsland, 1957). In amphibian eggs such measurements were performed by Konopacka (1908) and Ödquist (1922) on the cytoplasm and by Selman & Waddington (1955) on the cortex. However, since the observations of the latter authors were restricted to dividing eggs, a report on the cortical consistency of uncleaved amphibian eggs determined by the centrifugal method is not available.
L’influence favorable du foie embryonnaire sur l’hématopoïèse in vitro dans la moelle osseuse de l’embryon de poulet
Authors: Salvatorelli Germano 
Published: April 2021

ABSTRACT
Pendant le développement embryonnaire du poulet, on peut noter la succession de différents foyers d’érythropoïèse (Romanoff, 1960; Le Douarin, 1966):
les îlots de Wolff dont l’activité se déroule entre le 1er et 2ème jour d’incubation; le sac vitellin érythropoïétiquement actif du 4ème au 19ème jour d’incubation; le foie et la rate dont la faible activité se déroule entre le 7ème et le lOème jour d’incubation; la moelle osseuse dont l’activité commence au 12ème jour d’incubation et qui deviendra chez l’adulte le seul organe ayant une activité érythropoïétique.
Programming of gastrulation during the second cleavage cycle in Limnaea stagnalis: a study with lithium chloride and actinomycin D
Authors: Geilenkirchen W. L. M. 
Published: April 2021

ABSTRACT
It is well known that treatment with LiCl can cause abnormal embryonic development, but its mode of action is still uncertain (Gustafson, 1954; Geilenkirchen, 1961; Lallier, 1964). It also remains to be shown whether LiCl enters the egg cell at early developmental stages and acts internally, or does not penetrate into the cell and is active only at the outer surface (Elbers, 1959).
Limb development in the polydactylous talpid3 mutant of the fowl
Authors: Hinchliffe J. R. , Ede D. A. 
Published: April 2021

ABSTRACT
Talpid 2 limb development is characterized by excessive elongation of the apical ectodermal ridge (AER). In the forelimb the talpid2 AER is of normal length during stages 22 and 23, but at stage 28 it exceeds the normal by about 65%. In the hindlimb the talpid2 AER is of normal length during stages 22 – 24, but at stage 27 it exceeds the normal by about 20%. Massive cell death is absent from the superficial mesenchyme of both fore and hind talpid2 limbs. Histological and histochemical studies show that areas of dead cell groups rich in acid phosphatase activity are absent in talpid2 from the positions in the superficial limb mesenchyme in which they occur in the normal. This absence of cell death in the limb superficial mesenchyme is thought to account for (a) the abnormal sculpturing of talpid2 limbs, and (b) the excessive elongation of the talpid2 AER, through apical ectodermal maintenance factor (AEMF) being available from areas of mesenchyme normally undergoing necrosis and lacking AEMF. The abnormal talpid2 forelimb skeleton originates in an anomalous pattern of mesenchymal condensation forming the membranous skeleton at stage 26. Talpid2 limb mesenchyme shows an abnormal pattern of alkaline phosphatase distribution beginning at stage 26. The relationship between the abnormal pattern of limb mesenchymal condensation and the absence of massive cell death in the superficial mesenchyme is not understood. Talpid 3 limb development is discussed in relation to other cases where genes affect the pattern of cell death, and in relation to other examples of polydactyly.
Chromosome changes in embryos treated with various teratogens
Authors: Soukup S. , Takacs E. , Warkany J. 
Published: April 2021

ABSTRACT
Pregnant animals were treated with five chemical teratogens and a teratogenic dietary regime. Embryos were examined for chromosome changes in squash or ‘direct method’ preparations at various times after administration of the teratogen.
Embryos from rats treated with a teratogenic dose of nitrogen mustard or chlorambucil showed a peak of less than 20 % metaphase figures with chromosome abnormalities. Streptonigrin produced less than 10 %. The maximum chromosome abnormalities appeared within 24 h after injection and almost all abnormal metaphase figures disappeared within 48 h after injection.
Other chemical teratogens such as hydroxyurea injected into pregnant rats and thalidomide fed to pregnant rabbits produced no detectable chromosome abnormalities in the embryos. There were also no abnormal metaphase figures detectable in rat embryos after maternal exposure to a riboflavin-deficient diet.
The regeneration of limbs in adult anurans
Authors: Goode Robert P. 
Published: April 2021

ABSTRACT
The regeneration of limbs, after simple amputation, in two families (four genera) of primitive anurans was investigated. All produced hypotypic regenerates of varying size and degree of morphogenesis. Despite certain differences possibly related to phylogenetic affinities, both Discoglossidae and Pipidae regenerated in similar fashion. Regenerates consisted chiefly of well-developed rods of cartilage, surrounded by connective tissue and skin. Muscle regeneration was minimal, resulting in the formation of small striated slips. The role of the stump tissues and their possible relation to the development of the hypotypic regenerate was discussed.
The control of cell number in the lumbar ventral horns during the development of Xenopus laevis tadpoles
Authors: Prestige M. C. 
Published: April 2021

ABSTRACT
The developing limb has been amputated by many workers in several species and in each case the number of surviving motor neurones on the side of the operation was less than normal. This may be observed among the mammals (e.g. Barron, 1945), birds (e.g. Hamburger, 1934), urodeles (e.g. Stultz, 1942), and anurans (e.g. May, 1930). The loss of motor neurones after amputation in adults appears to have been first noticed by Vulpian (1868) and Johnson & Clarke (1868). The early evidence is reviewed by Sherrington (1893) and the later by Piatt (1948). The control that the developing leg has over proliferation, migration, maintenance and degeneration of ventral horn cells has been most completely analysed in the chick, notably by Hamburger (1934, 1939, 1958), Hamburger & Keefe (1944), Bueker (1943, 1944, 1945a), Barron (1946, 1948), Mottet (1952) and Mottet & Barron (1954). Less is known about this in Anura. May (1930, 1933) has recorded that in Discoglossus motor area hyperplasia can be produced by supernumerary limbs, and that the lateral motor horn (ventral horn) can be suppressed by replacement of the limb area with skin grafts. Bueker (1945b) found a frog (Rana) with three functional hind legs on one side; this had a hyperplasia of 22-7% in the ventral horn. Beaudoin (1955) ablated the early limb-bud in Rana pipiens and found a terminal hypoplasia of 82% in the ventral horn. Counts at intermediate stages were interpreted by him as indicating that the operation had delayed differentiation and the normal loss of cells on that side. In Bufo vulgaris, Perri (1956a) removed the hind-limb area at tailbud stages, and found that the ventral horn developed normally up to digit stages, when it regressed. The same happened when the isolated spinal cord was transplanted (Perri, 1956b). Three out of six animals with motile supernumerary limbs had hyperplastic spinal cords on the side of graft; this was not seen in any of the cases with non-motile grafts (Perri, 1957). Supernumerary limbs only became motile when innervated by limb plexus fibres, and never induced formation of new ventral horns in trunk regions. Perri therefore concluded that for the full development of the ventral horn, both regional intrinsic and also extrinsic limb factors were essential, the former necessarily acting before the latter.
Yolk distribution and utililization during early development of a teleost embryo (Brachydanio rerio)
Authors: Thomas Robert J. 
Published: April 2021

ABSTRACT
The work of Oppenheimer (1934, 1936) and Tung (1955, see also Devillers, 1961) suggests that an embryo such as Fundulus, a marine teleost, explanted at early cleavage (two-cell stage) is more dependent upon the amount of periblast yolk included in an explant than is an embryo that is more advanced prior to explanation. In other words, ‘if it (the embryo) is explanted before a so-called critical stage, the blastoderm turns into a hyperblastula (a non-differentiated mass of cells); if it is explanted after that, it undergoes differentiation. The critical stage corresponds to eight blastomeres in Carassius, thirty-two in Fundulus, and a young blastula in Salmo’ (Devillers, 1961, p. 391). The zebrafish, Brachydanio rerio, with a smaller egg than these fish, has not been characterized by explantation. Devillers, in summary, states that ‘these results mean that a substance indispensable for differentiation exists in the yolk sphere’ (p. 392). He continues, ‘On the other hand, how this hypothetical material may reach the blastoderm needs to be explained. The base of the blastoderm is in direct contact with the periblast in the early stages; later on, this syncytium ‘buds’ off blastomeres that add themselves to the embryonic disc’ (p. 397). He then asks the question ‘but then how can one explain that in later stages the syncytium can still impose an orientation on the germ? Are diffusing organizing substances involved?’ (p. 397).
Etude autoradiographique de la synthèse des ADN, ARN et protéines dans l’œsophage embryonnaire de Souris à l’aide de l’actinomycine D
Authors: Soriano Par Luis 
Published: April 2021

ABSTRACT
L’actinomycine D est capable à des doses modérées d’inhiber la synthèse d’ARN dépendant du ADN, et à des doses plus fortes elle peut affecter la synthèse des ARN et protéines cytoplasmiques dans les cellules animales (Goldberg & Rabinovitz, 1962; Caspersson, Farber, Foley & Killander, 1963; Franklin, 1963). D’autre part, ces résultats ont été confirmés en culture de cellules et d’organes par l’utilisation des méthodes autoradiographiques (Wessells, 1964; Yaffe & Feldman, 1964; Yaiïe & Fuchs, 1967).
Why molecular biology needs palaeontology
Authors: Morris S. Conway 
Published: April 2021

ABSTRACT
Molecular biology has re-opened the debate on metazoan diversification, including the vexing question of the origin of the major body plans (phyla). In particular, sequence analyses of rRNA have reconfigured significantly metazoan phylogeny, while homeobox genes suggest there could be an underlying similarity of developmental instructions in nominally disparate phyla. Despite this dramatic progress I argue that this renaissance of activity is lop-sided, but can be redressed by palaeontological data, especially from the Cambrian and immediately preceding Vendían. The fossil record complements and amplifies the conclusions derived from molecular biology, notably in the early radiation of cnidarians (Ediacaran faunas) and key steps in the diversification of the protostomes.
Evolutionary developmental biology of the tetrapod limb
Authors: Hinchliffe J. Richard 
Published: April 2021

ABSTRACT
New insights into the origin of the tetrapod limb, and its early development and patterning, are emerging from a variety of fields. A wide diversity of approaches was reported at the BSDB Spring Symposium on ‘The Evolution of Developmental Mechanisms’ (Edinburgh, 1994); here I review the contributions these various approaches have made to understanding the evolutionary developmental biology of the tetrapod limb. The fields covered included palaeontology, descriptive embryology, experimental embryological analysis of interactions within developing limbs plus description and manipulation of homeobox gene expression in early limb buds. Concepts are equally varied, sometimes conflicting, sometimes overlapping. Some concern the limb ‘archetype’ (can the palaeon tologists and morphologists still define this with precision? how far is there a limb developmental bauplan?); others are based on identification of epigenetic factors (eg secondary inductions), as generating pattern; while yet others assume a direct gene-morphology relationship. But all the contributors ask the same compelling question: can we explain both the similarity (homology) and variety of tetrapod limbs (and the fins of the Crossopterygians) in terms of developmental mechanisms?
The evolution of insect patterning mechanisms: a survey of progress and problems in comparative molecular embryology
Authors: Sander Klaus 
Published: April 2021

ABSTRACT
This report surveys data and interpretations presented by speakers in the Arthropod Session of the 1994 BSDB Spring Symposium. After a short review of phylogenetical aspects in premolecular insect embryology, the following topics are discussed: the ancestral germ type of pterygote insects, correlations between oogenesis and embryonic pattern formation, the universality or otherwise of bicoid as the anterior morphogen, novel functions in the insect Hox complex, the formal asymmetry between evolution and decay of complex gene networks, novel regulatory interactions as the main cause of evolutive changes, the repeated activity of conserved gene networks in successive steps of ontogenesis and strategies for future research. Interspersed are some unpublished data on oogenesis and pattern formation in lower dipterans, and their possible evolutionary implications.