Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 181 (1977), S. 261-265 
    ISSN: 1432-041X
    Keywords: Amphibian ectoderm ; Cyclic nucleotides ; Primary embryonic induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Isolated amphibian (Triturus alpestris) gastrula ectoderm was treated with cyclic nucleotides for 24 h and cultured up to 12 days. Explants treated with$cyclic N6-Monobutyryl-adenosine-3′∶5′-monophosphate, cyclic Dibutyryladenosine-3′∶5′-monophosphate and cyclic Dibutyrylguanosine-3′∶5′-monophosphate in a concentration of 10−3 and 10−5 M did not differentiate into mesoderm- or endoderm-derived tissues. The number of explants with small neural and neuroid structures did not exceed the percentage found in the control series. Inductions could also not be obtained when ectoderm was dissociated prior to the treatment with cyclic nucleotides, or when theophylline (which inhibits phosphodiesterase) was added to the culture medium. The results are discussed with regard to the possible mode of action of the vegetalizing factor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-041X
    Keywords: Immobilized inducing factors ; Biological activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The inducing activity of the vegetalizing factor decreases after covalent coupling to CNBr-Sepharose with reduced binding capacity. The residual inducing activity is probably due to the release of a small amount of the factor from Sepharose beads. Covalent coupling to activated CH-Sepharose completely inactivated the vegetalizing factor, whereas the neuralizing factor retained its full activity. The biological activity was also very much reduced when the vegetalizing factor was bound to Sephadex beads, a derivative of dextran. Fully active factor was recovered after enzymatic degradation of the dextran matrix with dextranase. The experiments suggest that the neuralizing factor acts on the cell surface of ectoderm cells, whereas the vegetalizing factor must probably be internalized to become biologically active.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 203 (1993), S. 28-33 
    ISSN: 1432-041X
    Keywords: Mesoderm differentiation ; Marginal zone ; Animal region ; Amphibia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Embryos of Ambystoma mexicanum from the late morula to the late blastula stage were dissected and cultivated in varying combinations. The marginal zone (presumptive mesoderm) when isolated together with the vegetal region differentiated to notochord after dissection from early blastulae, but did not differentiate to other tissues. When isolated from middle to late blastulae, in addition myoblasts and mesenchyme were formed. The marginal zone isolated together with the animal region (presumptive ectoderm) differentiated to notochord, muscle, mesenchyme, renal tubules and mesothelium irrespective of the stage of dissection. Combination of isolated animal and vegetal regions did lead to the induction of mesodermal organs. The experiments suggest that further steps in the differentiation of mesodermal organs after the induction of mesoderm by the vegetalizing factor depend on factors from the animal region, which are involved in pattern formation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-041X
    Keywords: Neural induction ; Basic fibroblast growth factor ; Triturus alpestris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ectoderm was isolated from early gastrulae of Triturus alpestris and induced with recombinant basic fibroblast growth factor (b-FGF). Neural tissue differentiated in about 38% of the explants which were induced by 2,5 μg/ml FGF. These explants do not contain other tissues, or contain only small amounts of mesenchyme and melanophores which are probably derived from induced neural crest. It is therefore unlikely that these neural tissues are secondarily induced. The other explants contain predominantly blastema tissue, endothelium/ mesothelium, small amounts of skeletal muscle and, rarely, notochord besides neural tissues. The mitotic rate was enhanced in about 20% of the induced explants. Possible mechanisms for the unexpected neural-inducing activity of b-FGF in Triturus ectoderm are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 149 (1956), S. 45-72 
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 163 (1969), S. 316-324 
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Rohfraktionen aus 9 Tage alten Hühnerembryonen, die neuralisierenden und mesodermalisierenden Induktionsfaktor enthielten, sowie angereicherter mesodermalisierender Faktor wurden mit Thioglykolsäure sowie mit 2-Mercaptoäthanol behandelt. Die Fraktionen wurden an Gastrulen vonTriturus alpestris oderAmbystoma nach der Implantationsmethode getestet. Der mesodermalisierende Faktor wird inaktiviert. Die Aktivität des neuralisierenden Faktors bleibt dagegen erhalten.
    Notes: Summary Crude extracts from 9 days old chicken embryos containing neuralizing and mesodermalizing inducing factors as well as purified mesodermalizing factor were incubated with thioglycolic acid and with 2-Mercaptoethanol. The fractions were tested by implanting into early gastrulae ofTriturus orAmbystoma. The mesodermalizing factor is inactivated whereas the neuralizing factor does not lose its activity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 184 (1978), S. 285-299 
    ISSN: 1432-041X
    Keywords: Embryonic induction ; Sepharose bound factors ; Biological activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Covalent binding to bromoacetyl-cellulose inactivates the vegetalizing factor. The bound factor is however still able to form a complex with an inhibitor for the factor. Covalent binding to CNBr-Sepharose likewise inactivates the vegetalizing factor. The neuralizing factor on the other hand is not inactivated when covalently bound to CNBr-Sepharose. When a crude fraction which contains the neuralizng factor as well as the vegetalizing factor is bound to CNBr-Sepharose the vegetalizing activity is greatly decreased whereas the neuralizing activity is not reduced. This suggests that the mechanisms of action of the two factors are quite different. Whereas the vegetalizing factor must be incorporated into the cells, the neuralizing factor interacts with the plasma membrane of competent ectoderm cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 187 (1979), S. 231-244 
    ISSN: 1432-041X
    Keywords: Amphibia ; Mesoderm formation ; Secondary factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A highly purified vegetalizing factor induces endoderm preferentially in amphibian gastrula ectoderm. After combination of this factor with less pure fractions, a high percentage of trunks and tails with notochord and somites are induced. The induction of these mesodermal tissues depends on secondary factors which may act on plasma membrane receptors of the target cells. The secondary factors are probably proteins as they are inactivated by trypsin or cellulose-bound proteinase K. They are not inactivated by thioglycolic acid. The implication of these findings for tissue determination and differentiation in normal development in relation to the anlageplan for endoderm and mesodermal tissues is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 193 (1984), S. 13-18 
    ISSN: 1432-041X
    Keywords: Amphibia ; Neural induction ; Ectoderm ; Activation of masked factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Isolated gastrula ectoderm has no neural-inducing activity and does not differentiate into neural tissues. It has, however, a high neural-inducing capacity, but the inducing factors are present in a masked, inactive form. The inducing factors are partially activated by homogenization and by freezing of the homogenate and are fully activated by treatment with ethanol. The relative distribution of inducing factors in different subcellular fractions changes after treatment with demecolcine and cytochalasin B or after autolytic incubation of the homogenate. The inducing activity of the high-speed supernatant is enhanced under these conditions. The experiments suggest that the activation of neuralizing factor(s) depends on the release from complex structures. Cytoskeletal elements seem to be involved. When early neural plate homogenate was fractionated, the high-speed supernatant showed neural-inducing activity. This is in contrast to the high-speed supernatant from the ectoderm homogenate, which shows no such activity.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 195 (1986), S. 117-122 
    ISSN: 1432-041X
    Keywords: Plasma membranes ; Amphibian embryogenesis ; Neural induction ; Xenopus laevis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Plasma membranes were isolated in high yield from Xenopus gastrulae by repeated sedimentation in discontinuous sucrose gradients. Most of the yolk was separated by lowspeed sedimentation before centrifugation on the discontinuous sucrose gradients. The isolation of plasma membranes was followed by covalent labelling of the surface of dissociated gastrula cells with diazoniobenzene sulphonate, by electron microscopy and the distribution of enzymatic markers. The isolated plasma membranes have a low neural inducing activity as compared to other cell constituents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...