An Experimental Analysis of the Development of the Haploid Syndrome in Embryos of Xenopus laevis

Development ◽  
1963 ◽  
Vol 11 (1) ◽  
pp. 267-278
Author(s):  
Louie Hamilton
Keyword(s):  
Xenopus Laevis ◽  
Experimental Analysis ◽  
Rana Pipiens ◽  
Animal Pole ◽  
Pole Cells

Haploid vertebrates may occur spontaneously but are very rare (Fankhauser, 1941; Humphrey & Fankhauser, 1957); however, haploids may be experimentally produced in fish (Swarup, 1959) and in mammals (Beatty, 1953), while amphibian eggs may be so treated that all developing embryos are haploid (Porter, 1939; Gurdon, 1960). The full descriptions of the development of haploid Rana pipiens (Porter, 1939) and R. nigromaculata (Miyada, 1960) apply so well to Xenopus laevis that only the most important points will be touched on here. Haploid amphibians may be identified at the beginning of gastrulation since their animal pole cells are smaller at a given stage than are those of diploids. In all haploid Anura the onset of gastrulation is delayed, and thereafter haploids become progressively more retarded in their development. Their neural plates are shorter, and when the neural folds have closed it can be seen that the embryos are microcephalic and suffer from lordosis and a bulging abdomen.

scholarly journals Gastrulation movements provide an early marker of mesoderm induction in Xenopus laevis

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 339-349 ◽  
Author(s):  
K. Symes ◽  
J.C. Smith
Keyword(s):  
Cell Division ◽  
Xenopus Laevis ◽  
Early Response ◽  
Model System ◽  
Mesoderm Induction ◽  
Animal Pole ◽  
Inductive Interaction ◽  
Vegetal Pole ◽  
Pole Cells ◽  
General Appearance

The first inductive interaction in amphibian development is mesoderm induction, in which an equatorial mesodermal rudiment is induced from the animal hemisphere under the influence of a signal from vegetal pole blastomeres. We have recently discovered that the Xenopus XTC cell line secretes a factor which has the properties we would expect of a mesoderm-inducing factor. In this paper, we show that an early response to this factor by isolated Xenopus animal pole regions is a change in shape, involving elongation and constriction. We show by several criteria, including general appearance, timing, rate of elongation and the nonrequirement for cell division that these movements resemble the events of gastrulation. We also demonstrate that the movements provide an early, simple and reliable indicator of mesoderm induction and are of use in providing a ‘model system’ for the study of mesoderm induction and gastrulation. For example, we show that the timing of gastrulation movements does not depend upon the time of receipt of a mesoderm-induction signal, but on an intrinsic gastrulation ‘clock’ which is present even in those animal pole cells that would not nomally require it.

Involvement of the guanine nucleotide exchange factor xLARG in the epiboly of Xenopus laevis embryo animal pole cells

BIOPHYSICS ◽  
2010 ◽  
Vol 55 (6) ◽  
pp. 921-925
Author(s):  
D. O. Kiryukhin ◽  
L. A. Shustikova ◽  
E. E. Kopantseva ◽  
N. N. Luchinskaya ◽  
A. V. Belyavskii
Keyword(s):  
Xenopus Laevis ◽  
Guanine Nucleotide Exchange Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Animal Pole ◽  
Laevis Embryo ◽  
Guanine Nucleotide Exchange ◽  
Xenopus Laevis Embryo ◽  
Nucleotide Exchange Factor ◽  
Pole Cells

An ultrastructural study of the effects of wheat germ agglutinin (WGA) on cell cortex organization during the first cleavage of Xenopus laevis eggs. II. Cortical wound healing

1979 ◽  
Vol 37 (1) ◽  
pp. 59-67
Author(s):  
M. Geuskens ◽  
R. Tencer
Keyword(s):  
Wound Healing ◽  
Plasma Membrane ◽  
Electron Microscope ◽  
Xenopus Laevis ◽  
Ultrastructural Study ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Cell Cortex ◽  
Animal Pole ◽  
Annular Zone

Uncleaved fertilized eggs of Xenopus laevis treated with wheat germ agglutinin (WGA) have been pricked at the animal pole both inside and outside the regressed furrow region. The wounded cortex of both regions has been studied with the electron microscope and compared with the same region of wounded, untreated eggs. In all 3 cases, filaments are organized in an annular zone in the damaged cortex. When the surface is pricked outside the regressed furrow of WGA-treated embryos, bundles of microfilaments radiate from the ring and extend in deep folds which form a ‘star’ around the wound at the surface of the embryo. However, when the surface is pricked in the new membrane of the regressed furrow, filaments are intermingled with internalized portions of the plasma membrane. It is suggested that, when the surface is pricked outside the furrow region, more filaments are mobilized to counteract the tangential retraction of the membrane which has acquired more rigidity after WGA binding.

The development of the tectum in Xenopus laevis: an autoradiographic study

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 87-115
Author(s):  
K. Straznicky ◽  
R. M. Gaze
Keyword(s):  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Optic Tectum ◽  
Tritiated Thymidine ◽  
Dorsal Surface ◽  
Autoradiographic Study ◽  
Cell Type ◽  
Pole Cells ◽  
Serial Addition ◽  
The Times

The development of the optic tectum in Xenopus laevis has been studied by the use of autoradiography with tritiated thymidine. The first part of the adult tectum to form is the rostroventral pole; cells in this position undergo their final DNA synthesis between stages 35 and 45 or shortly thereafter. Next, the cells comprising the ventrolateral border of the tectum form. These cells undergo their final DNA synthesis at or shortly after stage 45. Finally the cells comprising the dorsal surface of the adult tectum form, mainly between stages 50–55. This part of the tectum originates from the serial addition of strips of cells medially, which displace the pre-existing tissue laterally and rostrally. The formation of the tectum is virtually complete by stage 58. The tectum in Xenopus thus forms in topographical order from rostroventral to caudo-medial. The distribution of labelled cells, several stages after the time of injection of isotope, indicates that, at any one time, a segment of tectum is forming which runs normal to the tectal surface and includes all layers from the ventricular layer out to the surface. In Xenopus, therefore, the times of origin of tectal cells appear to be related not to cell type or tectal layer but to the topographical position of the cells across the surface of the tectum.

scholarly journals The mRNA encoding a β subunit of heterotrimeric GTP-binding proteins is localized to the animal pole of Xenopus laevis oocyte and embryos

1996 ◽  
Vol 59 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Eric Devic ◽  
Laurent Paquereau ◽  
Karine Rizzoti ◽  
Armelle Monier ◽  
Bernard Knibiehler ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Binding Proteins ◽  
Xenopus Laevis Oocyte ◽  
Β Subunit ◽  
Animal Pole ◽  
Gtp Binding Proteins ◽  
Gtp Binding

Mesoderm-inducing properties of INT-2 and kFGF: two oncogene-encoded growth factors related to FGF

Development ◽  
1989 ◽  
Vol 106 (1) ◽  
pp. 79-83 ◽  
Author(s):  
G.D. Paterno ◽  
L.L. Gillespie ◽  
M.S. Dixon ◽  
J.M. Slack ◽  
J.K. Heath
Keyword(s):  
Growth Factors ◽  
Embryonic Development ◽  
Xenopus Laevis ◽  
Dna Synthesis ◽  
Signalling Pathways ◽  
Control Mechanisms ◽  
Animal Pole ◽  
Receptor Signalling ◽  
Mammalian Embryogenesis ◽  
Mesoderm Formation

Many theories of neoplasia suggest that oncogenic transformations result from aberrations in the control mechanisms which normally regulate growth and differentiation during embryonic development. It has recently become clear that many proto-oncogenes are differentially expressed during embryonic development and may thus be important embryonic regulatory molecules. We report here that the products of two transforming oncogenes int-2 and hst/ks (now called kfgf) can, with different potencies, induce mesoderm formation in isolated Xenopus laevis animal pole explants and stimulate DNA synthesis in mammalian fibroblasts. The results suggest that these proteins may function as mesoderm inducers in mammalian embryogenesis and that similar receptor/signalling pathways may be utilized for developmental and oncogenic processes. Finally, we have shown that the Xenopus assay system used in this study provides a powerful screen for protein factors that are active in development.

Circular mitochondrial DNA from Xenopus laevis and Rana pipiens

Chromosoma ◽  
1967 ◽  
Vol 20 (4) ◽  
pp. 445-449 ◽  
Author(s):  
David R. Wolstenholme ◽  
Igor B. Dawid
Keyword(s):  
Mitochondrial Dna ◽  
Xenopus Laevis ◽  
Rana Pipiens

Synthesis of mitochondrial RNA by full-grown and maturing oocytes of Rana pipiens and Xenopus laevis

1975 ◽  
Vol 45 (1) ◽  
pp. 44-55 ◽  
Author(s):  
Andrew C. Webb ◽  
Michael J. LaMarca ◽  
L.Dennis Smith
Keyword(s):  
Xenopus Laevis ◽  
Rana Pipiens ◽  
Mitochondrial Rna

scholarly journals Xenopus laevis oocytes infected with multi-drug–resistant bacteria: implications for electrical recordings

2011 ◽  
Vol 138 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Denice O'Connell ◽  
Karen Mruk ◽  
Jessica M. Rocheleau ◽  
William R. Kobertz
Keyword(s):  
Xenopus Laevis ◽  
Mammalian Cells ◽  
Resistant Bacteria ◽  
Xenopus Laevis Oocytes ◽  
Xenopus Laevis Oocyte ◽  
Drug Resistant ◽  
Animal Pole ◽  
Antibiotic Cocktail ◽  
Storage Media ◽  
Drug Resistant Bacteria

The Xenopus laevis oocyte has been the workhorse for the investigation of ion transport proteins. These large cells have spawned a multitude of novel techniques that are unfathomable in mammalian cells, yet the fickleness of the oocyte has driven many researchers to use other membrane protein expression systems. Here, we show that some colonies of Xenopus laevis are infected with three multi-drug–resistant bacteria: Pseudomonas fluorescens, Pseudomonas putida, and Stenotrophomonas maltophilia. Oocytes extracted from infected frogs quickly (3–4 d) develop multiple black foci on the animal pole, similar to microinjection scars, which render the extracted eggs useless for electrical recordings. Although multi-drug resistant, the bacteria were susceptible to amikacin and ciprofloxacin in growth assays. Supplementing the oocyte storage media with these two antibiotics prevented the appearance of the black foci and afforded oocytes suitable for whole-cell recordings. Given that P. fluorescens associated with X. laevis has become rapidly drug resistant, it is imperative that researchers store the extracted oocytes in the antibiotic cocktail and not treat the animals harboring the multi-drug–resistant bacteria.

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