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At least 757 records · Page 42Linked to original sources
PubMed1991

[Chalone-antichalone system of the liver in different animals and its state depending on physiological rhythms in amphibia].

The chalone-antichalone activity in the mollusc (anodonta), fish, frog, bird, mammalians liver preparations is determined. Inspite of the fact that chalone-antichalone content varies greatly in different animals livers, in most of them the chalone-antichalone ratio is approximately equal and doesn't increases 2.0. In the frog livers during the hibernation period the chalone is not determined. Its synthesis begins at the hibernation exit and it becomes active in the spring-time.

Amphibians↗
PubMedDate not supplied

Circannual rhythms in the activity of the parathyroid gland and ultimobranchial body cells of the frog Rana temporaria (Anura, Amphibia).

The annual activity of the parathyroid gland cells and those of the ultimobranchial body cells of the frog Rana temporaria is quantitatively investigated by a morphometric study. A cosinor analysis shows a periodic succession of different parameters. The secretory activity of the parathyroid cells starts after a maximal value of external temperature in July. This activity is followed by an increase of plasma calcium which seems to induce the activity of the ultimobranchial cells.

Analysis of Variance↗
PubMed1990

Dental laminae and teeth of embryonic Ichthyophis glutinosus (L.) (Amphibia: Gymnophiona).

Light microscopic studies of dental lamina anlagen and the form and order of primary teeth were undertaken on embryos of Ichthyophis glutinosus. The palate dental lamina responsible for the dentition of the vomers and the palatine portions of the maxillopalatines develops unpaired on the lingual sides of these bones. Similarly, the upper jaw dental lamina is undivided in the rostro-median; it originates lingual to the premaxillaries. Orally paired and aborally unpaired, the dental laminae of the lower jaw are laid down along the inner sides of their respective bony anlagen. Of these, the orally undivided dental lamina corresponds to the dental portion of the caudally fused lower jaw bones while the aboral pair of dental laminae correspond to the splenial portions. When fully developed, the primary teeth are unbladed-conical and divided. They are labio-marginal, monostichous and pleurally anchored.

Amphibians↗
PubMed1975

Cathodal proteins from primitive (embryonic) red cells of amphibia. Isolation and characterization.

A group of abundant (15% of the soluble protein) nonhemoglobin proteins was isolated from the primitive (embryonic) red cells found in tadpoles, using the cationic properties of the proteins at pH 8.6 to separate them from hemoglobin and other red cell proteins. The cathodal proteins (CP) were resolved into five components, and the two most predominant proteins were separated and characterized. Purified CP-1b and CP-2 had an amino acid composition similar to that of unfractionated cathodal proteins and to each other, except for small variations in the lysine and half-cystine content. The molecular weight of the purified CP-1b and CP-2 was 13 to 14,000, determined by gel filtration chromatography and electrophoresis in the presence of sodium dodecyl sulfate. Cathodal proteins were immunologically related although there were quantitative differences in reactivity. The concentration of cathodal proteins in primitive (embryonic) red cells was 100 times that in definitive (adult) red cells coincided with the replacement of primitive red cells. The synthesis of the cathodal proteins appeared to continue throughout the life of the primitive red cells; when hemoglobin synthesis declined in primitive red cells, approximately half of the protein synthesized by the cells was cathodal protein. Although the function of the cathodal proteins is as yet unknown, the data suggest that the cathodal proteins are a unique characteristic of erythroid differentiation in early development.

Amino Acids↗
PubMed1986

[Neuropeptides of the sympathetic ganglia of mammals and amphibia (comparative immunocytochemical study)].

The investigation has been performed by means of the immunohistochemical method. Secondary antibodies are marked with isothiocyonate, or with horseradish peroxidase. Localization of enkephalin, cholicystokinin, substance P and gonadoliberin is studied in luminescent and electron microscope in pre- and paravertebral ganglia of the frog, guinea pig, rat and cat. The data on immunoreactivity of neuronal bodies and plexuses are proved and detalized; chemism of interneuronal synapses is studied at electron microscopic level. The analysis of synapses in the sympathetic ganglia is performed for the first time.

Ambystoma↗
PubMed1987

Comparative data on acetylcholinesterase cytochemistry in various chromaffin cell types of Discoglossus pictus (Amphibia, Anura).

The cytochemical localization of acetylcholinesterase (AChE) activity was studied in the adrenal chromaffin cells of Discoglossus pictus. Reaction end-products were associated with all types of chromaffin cells, i.e. adrenaline (A), noradrenaline (N) and small granule chromaffin (SGC-A, SGC-N) cells, and nervous elements present in the gland. The SGC-A and SGC-N showed the same intensity of AChE reaction in A and N cells, respectively. On the whole, the A and SGC-A cells were more reactive than the N and SGC-N cells. The functional role of the SGC cells is discussed on the basis of the cytochemical results.

Acetylcholinesterase↗
PubMed1988

Cytochemical study of larval skin in Amphibia: occurrence of ruthenium red positive cells in cutaneous gland anlagen.

During a cytochemical investigation into the development of cutaneous gland buds in amphibian larvae (both anuran and urodele), ruthenium red (RR) positive cells were found in the anlagen. These cells, with diffuse deposits of the polycation dye in their cytoplasms, were first detected on the lateral surface of still intraepidermal gland buds. Later, during segregation of anlagen from the epidermis, the reactive cells were followed whilst they converged towards the apex of the gland nest. These findings of a remarkable penetration of RR through intact plasma membranes are discussed in the light of the staining characteristics of the polycation dye. Furthermore, the mechanism regulating morphogenesis of amphibian cutaneous glands is briefly compared with the morphogenetic patterns of large exocrine glands in higher vertebrates. It is suggested that during fixation RR penetrates morphogenetically active cells, following the same pathways as calcium under physiological conditions. Calcium inflow correlates with the occurrence of thin, possibly contractile, filaments in these cells and also agrees with cell migration during morphogenesis.

Animals↗
PubMed1989

[Stimulation of sodium transport by cobalt ions in the skin of amphibia against a background of aldosterone action].

Sodium transport across toad Bufo marinus and frog Rana temporaria skin was enhanced by aldosterone added to Ringer solution at the basal plasma membrane. Cobalt ions applied to the outer surface of amphibian skin have increased sodium transport stimulated by aldosterone. The regulatory sites of the sodium channel macromolecule seem to be located on both surfaces of the channel apical membrane.

Aldosterone↗
PubMed1985

[Experimental demonstration of the annual characteristic of the lines of arrest of skeletal growth in Rana esculenta (Amphibia, anura)].

Different vital fluorescent labelling (tetracycline, calcein, xylenol orange, alizarine red S) have been injected in a series of young growing green frogs, caught near Paris and kept for 2 years in captivity under conditions quite similar to natural ones. The study of femur and phalanx has been carried out by ground sections observed in UV light and then colored with hematoxyline. The comparison between UV and transmitted light observations shows that the arrested growth lines are annual, laid during winter and never completely destroyed by bone remodelling. Then, they constitute a valuable criterion to assess the age of the individual.

Age Determination by Skeleton↗
PubMed1989

[Histologic study of the lumbar glands of Pleurodema thaul (Amphibia, Anura, Leptodactylidae)].

Frogs of the Pleurodema thaul species have a pair of prominent elevated cutaneous glands dorsolaterally, just posterior to the sacrum, which are named lumbar glands. We have studied histologically these glands and found that their chromatophores are disposed mainly immediately under the epidermis structuring a dermal chromatophore unit. Similar to the other anuran macroglands, the lumbar glands are constituted basically by granular alveoli filled with secretion. The presence of these granular alveoli and the typical distribution of the dermal chromatophores to suggest a defensive role for the lumbar glands. In most of the amphibians granular alveoli contain secretions with toxicity for several vertebrates. On the other hand, chromatophores in this frog species, probably play an aposematic function, since their disposition on the skin permits that the lumbar glands might be taken for eyes, probably giving to an eventual predator the impression that it may be an animal of higher dimensions.

Animals↗
PubMedDate not supplied

[The determination of ectodermal derivatives in various species of amphibia].

The process of labyrinth determination has been studied in amphibians (three Urodela and seven Anura species) using homoplastic transplantation of ear ectoderm, containing labyrinth material onto the abdominal wall of embryos of the same stage of development. The stage of appearance of organ-specific properties in ear ectoderm was determined and the increase of these properties in the course of development was observed. The frequency of ear vesicles formation, the level of their differentiation and their size served as criteria. These criteria allow to align the studied species into a row, where organ-specific properties appear earlier and most completely in representatives of Ranidae family and in Bufo viridis, and weakest, in smooth newt. A comparison of properties of labyrinth material and other areas of ectoderm allowed to conclude that specific differences in determination of different ectodermal primordia are based on specific peculiarities of the whole ectoderm. The appearance of these differences can be explained by the shift in the beginning of gastrulation towards later stages of cleavage during the evolution of amphibians.

Amphibians↗
PubMed1989

[The humane killing of fishes, amphibia, reptiles and birds].

Methods, whether or not acceptable in the correct killing of fish, amphibians, reptiles or birds, are reviewed. The acceptable or unacceptable character of each of these techniques is commented upon. The techniques are differentiated into mechanical, chemical and physical methods. Of all mechanical techniques, rendering an animal unconscious by a sharp blow on the head, followed by rapid decapitation is an acceptable method. Of the chemical techniques, inhalation of Halothane, CO2 + O2, or ether, are usually acceptable. Cutaneous absorption by bathing in a solution of the anaesthetic tricaine sulphonate (MS 222) is the method of choice in fish and amphibians. The injectable anaesthetics T61 and pentobarbital-Na are acceptable in all groups of animals. Physical techniques such as supercooling, heating or electrocution are either unacceptable or impracticable in veterinary practice. Attention is paid to the effects of each of these techniques on the animal, the executing individual and the owner. Technical details of the methods most preferable in the humane killing of animals are discussed.

Amphibians↗