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PubMedDate not supplied

[Appearance of secondary melanophore reactions in the ontogeny of anuran amphibia].

The development of physiological reactions of the dermal melanophores has been studied in Rana temporaria, R. ridibunda and Xenopus laevis. In these species, the background (secondary) reactions of melanophores appeared at different stages of larval development but their appearance was always timed with the eye slit closure.

Animals↗
PubMedDate not supplied

[Changes in the cellular localization of gamma-crystallins in the lens differentiation process in amphibia].

The lenses were studied in the Rana temporaria embryos by means of immunochemistry from the formation of lens vesicle till the end of metamorphosis. The rabbit antisera against gamma- and beta-crystallins of Rana temporaria were used. The materials were fixed by acetone or Carnois fixative. beta-crystallins were shown to appear simultaneously with gamma-crystallins at stage 31--32 (Dabagyan, Sleptzova, 1975). gamma-Crystallins appeared first in the lens fibers and later (stages 36--51) in the epithelial cells. From stage 52 (tail reduction) the immunofluorescence of gamma-crystallins in the epithelium fell sharply until full disappearance. At stage 54 (end of metamorphosis) a weak fluorescence of gamma-crystallins was found in the anterior part of epithelium only. gamma-Crystallins were not found in the epithelium of adult frogs.

Adsorption↗
PubMed1983

[Inhibitory effect of lectins extracted from Arachis hypogea and soybeans on germ cell migration in the embryo of Xenopus laevis (Amphibia, Anura)].

Effect of injection of Arachis hypogea (PNA) and Soybean (SBA) lectins on the migration of Xenopus primordial germ cells (PGCs) were investigated. PNA inhibited almost entirely the PGCs migration, more than SBA. Our results indicated that the inhibition of the migration could be a consequence of the lectin-induced alterations of cell surface properties.

Animals↗
PubMed1984

Tubular myelin structures in the lungs of amphibia. The mode of formation.

The lungs of the tree frog Hyla arborea and the toad Bufo bufo were fixed in glutaraldehyde with the addition of picric acid or tannic acid to visualize tubular myelin (TM), one of the forms of pulmonary surfactant. The lungs of both Hyla and Bufo are complex in structure and possess one type of pneumocytes containing numerous lamellar bodies (LBs). The alveolar lining layer in the lung of Hyla includes numerous LBs at different stages of transformation into a monolayer film, but the lattice is sparse, delicate and unstable. The structure of smooth membranes in the alveolar layer is not clearly visible and their thickness varies from 4.0 to 7.2 nm. In the lung of Bufo TM occurs commonly in the alveolar lining layer. Membranes of LBs are smooth particle-free bilayers of 8.1 to 12.0 nm thick. During transformation into TM, the membranes become covered by fuzzy coat and irregularly spaced rod-like particles of 8 to 13 nm in diameter. I suppose that these particles facilitate the maintenance of TM structures.

Animals↗
PubMed1980

[Light and electron microscopic studies of the structure and histochemistry of the oviduct epithelial cells (pars recta and pars convoluta I, II, III) in Salamandra salamandra (L.) (Amphibia, Urodela)].

The oviduct of the ovoviviparous Salamandra salamandra is differentiated into five readily distinguishable regions (1. pars recta, 2. p. convoluta I, 3. p. convoluta II, 4. p. convoluta III, 5. p. convoluta IV or uterus) due to the structure of its epithelial cells and the carbohydrate histochemistry of their secretory products. The epithelium of region 1-4 is mono-layered and exhibits ciliated and rather undifferentiated cells which both may contain small amounts of secretory material. Large amounts, however, are present in different gland cells restricted to discrete regions of the oviduct: microgranulocytes occur in the p. convoluta I, II, III, microspongiocytes in the p. convoluta II, III, groups of voluminous spongiocytes and granulocytes which form crypts are found in the p. convoluta I (spongiocytes I), in the p. convoluta II (granulocytes), and in the p. convoluta III (spongiocytes II). The uterine epithelium consists of a uniform cell type described elsewhere. All secretory cells contain neutral mucosubstances (in particular the granulocytes and microgranulocytes) and acid mucosubstances with carboxyl- and sulphate-groups. Sulphate ester groups are common in the mucigen globules of the spongiocytes and the microgranulocytes, whereas carboxylgroups and a demonstrable protein component seem to be predominant in the seromucous granulocytes. The secretory product of the microspongiocytes could not be characterized clearly. The ultrastructural features of the gland cells resemble those of other mucus secreting cells. The Golgi apparatus is the most prominent cell organelle of the spongiocytes and granulocytes. In the latter cells granular endoplasmic reticulum is invariable abundant. The secretory granules of all epithelial cells including the content of the vacuoles of the microspongiocytes as well as substances within the dictyosomes and associated vesicles are stained with the periodic acid--chromic acid--methenamine silver (PACAMS) technique suggesting periodic acid-reactive carbohydrate components. The oviducal gland cells of all pregnant and non-pregnant females investigated--specimens immediately after deposition of the jelly envelopes of the eggs could not be examined during this study--are filled with secretory material. It appears to be discharged at least by the spongiocytes and granulocytes into the lumen of the oviduct also beyond the time of secreting the jelly layers.

Animals↗