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At least 19 recordsLinked to original sources
PubMed1977

Comparative ultrastructural investigations of the uterine epithelium in the viviparous Salamandra atra Laur. and the ovoviviparous Salamandra salamandra (l.) (amphibia, urodela).

The uterine epithelium of the viviparous Salamandra atra and the ovoviviparous Salamandra salamandra was studied in non pregnant and ovulating females and in females during different stages of pregnancy. The epithelium of both species is organized in a monolayer. The epithelial cells are characterized by a moderate secretory activity, a variable amount of apical granules which include PAS-positive material and by some apical and basal exo- or endocytotic vesicles. Adjacent cells are joined by junctional complexes. The lateral surfaces form a tortuous boundary with adjoining cells which suggest that the epithelium is involved in transport. Sporadic light cells possess highly variable cytoplasmic inclusions and are not joined with neighbouring cells. Possibly they represent migratory cells. The entire epithelium, except for a small cranial portion of the uterus in S. atra, undergoes no remarkable morphological changes during the different physiological stages examined except that flattened cells seem to be more numerous in pregnant females. The results are discussed with regard to the possible supply of the developing young by the mother.

Animals↗
PubMed1975

[Demonstration and in vitro study of a complex reaction (rejection and facilitation) of the mother towards the embryo in the urodele amphibian Salamandra salamandra L].

Spleen cells from pregnant (but not from non-pregnant) Salamandra salamandra are cytotoxic in vitro for dissociated epidermal cells from their own embryos. Maternal serum inhibits this cytotoxicity. Analogies and differences are stressed in Salamandra salamandra between allograft rejection mechanisms and immune reactions towards embryos. They may contribute to an explanation of the delayed expulsion of embryos.

Animals↗
PubMed1979

[Homing behavior in Salamandra salamandra (L.)].

Homing behavior in salamanders (Salamandra salamandra) was studied in the field (52 adults) and in laboratory experiments (75 adult animals). Displacements, occluding of sense organs and experiments with different visual patterns revealed that the home-site orientation is guided by vision. While visual landmarks are most important, Salamandra is also able to use a moon-compass.

Animals↗
PubMed1979

The influence of prey experience on movement pattern preference in Salamandra salamandra (L.).

Groups of juvenile Salamandra salamandra were raised selectively with different types of prey. The influence of these conditions on the movement pattern preference was studied during the first six months after metamorphosis. Responses to a black horizontal bar moving continuously or stepwise at step frequencies between 0.25 and 8 steps/s were tested. The differently raised groups showed significant differences in their respective preference for stimulus movement patterns which corresponded with the movement pattern of their food. At the same time, superimposed upon this learning process, a general increase in the relative efficiency of continuous stimulus movement with regard to stepwise stimulus movement could be observed.

Animals↗
PubMed1977

[The maternal protection reaction against a mother's rejection of her own larva in Salamandra salamandra L].

In vitro experiments have shown that maternal spleen cells from Salamandra salamandra are cytotoxic to cells from their embryos. This reaction can be inhibited by maternal serum. In this paper, we show that maternal serum protection acts through two effects: by inactivating spleen cells and by protecting embryonic cells. The more numerous the embryos are in a female, the stronger the protection is. The effect of the maternal serum does not appear to be individual specific.

Animals↗
PubMed1978

Ultrastructural and morphometric study of the lung of the European salamander, Salamandra salamandra L.

Ultrastructural and morphometric investigations were performed on the lung of the European salamander, Salamandra salamandra L. Folds of first and second order are covered with a ciliated epithelium containing goblet cells. The respiratory surface of the lung is lined by a single type of cell which, in amphibians, combines features of type I and type II alveolar cells of the mammalian lung. In the salamander the respiratory and ciliated epithelial cells as well as goblet cells possess electron dense and lucent vesicles in their cytoplasm as well as lamellar bodies. A small amount of surfactant, composed most probably of phospholipids and mucopolysaccharides, was observed covering the entire inner surface of the lung. Morphometric methods were used to determine the dimensions of the perinuclear region of pneumocytes, the thickness of the air-blood barrier and lung wall, and also the diameter of capillaries. The thickness of the respiratory air-blood barrier was found to be considerably higher than that of the corresponding barrier in mammals.

Animals↗
PubMed1979

Scanning electron microscopy of microcorrosion casts of the vascular bed in the skin of the spotted salamander, Salamandra salamandra L.

Microcorrosion casts of blood vessels in the skin of the spotted salamander, Salamandra salamandra L., were studied using scanning eletron microscopy. The investigated vessels include a subepidermal network of respiratory capillaries and the vessels of poison glands. A hypothesis is proposed, according to which both types of vascular beds possess a common origin. Probable factors involved in the differentiation of the primary netword of the subepidermal vessels in larvae are indicated and speculation concerning the supposed mosaic type of circulation in the capillaries of the subepidermal respiratory bed is presented.

Animals↗
PubMed1979

An electron microscope study of the respiratory epithelium in the lungs of the fire salamander (Salamandra salamandra).

The respiratory epithelium in the lungs of the common fire salamander (Salamandra salamandra) has been studied by electron microscopy. The entire pulmonary gas-exchange area is covered by a continuous epithelium, the cells of which are all of the same type and are termed 'pneumonocytes'. Typically, each pneumonocyte is squamous and has attenuated sheets of cytoplasm which extend over the pulmonary capillaries. Its free surface bears squat microvilli, and osmiophilic inclusion bodies and other organelles are prominent in the cytoplasm. The lateral cell walls have numerous desmosomes and interdigitating cytoplasmic processes. Many cells send cytoplasmic processes deep into the substance of the lung septa. The morphological evidence suggests that the pneumonocytes are responsible for the secretion of pulmonary surface-active agents and for maintaining the integrity of the gaseous diffusion membrane.

Animals↗
PubMed1976

Ultrastructural localization of adenyl cyclase activity in the pancreas of two amphibian species (Salamandra salamandra L. and Rana esculenta L.).

The distribution of adenyl cyclase activity in the pancreas of one species of urodeles and anura has been investigated using electron microscopy. In both islet and acinar tissues the reaction product was located at the outer cell surfaces, while in nerve bundles it occurred in the cleft between axolemma and Schwann cell-extensions. The functional signification of the enzyme localization is discussed in relation to the findings of other authors.

Adenylyl Cyclases↗
PubMedDate not supplied

Antagonistic maternal immune reactions (rejection and facilitation) to the embryo in the urodele amphibian Salamandra salamandra lin.

In vitro assays have been employed to demonstrate that pregnant salamanders mount an immune reaction against their embryos. Maternal spleen cells kill up to 85% of dissociated embryonic epidermal cells during a 48 h incubation period. The degree of killing depends upon the ratio of maternal to embryonic cells and on the number of embryos borne by the mother. The cytotoxicity shows considerable specificity for the embryos of a given mother although a weak degree of killing can occur with embryos from other mothers, presumably due to some form of cross-reactivity. The effect is inhibited by the addition of maternal serum to the cultures. The degree of protection is also a function of the number of embryos borne by the mother. Pre-incubation experiments indicate that the maternal serum has a protective action on the embryonic cells which is largely specific for the female's own embryos (and suggested to be antibody in nature) and an inhibitory action on the maternal spleen cells which occurs also with spleen cells of other females (and suggested to be either an immune complex or a nonimmunological substances). An increase in beta protein peaks is seen following electrophoresis of sera from pregnant (and also allografted) salamanders. These findings indicate that the pregnant salamander mounts a double immune reaction against her embryos, an aggressive (rejection) reaction and a protective (facilitation) reaction.

Absorption↗
PubMed1978

Electron microscopic localization of Mg2+ -dependent adenosine triphosphatase activity in the amphibian pancreas (Salamandra salamandra L. and Rana esculenta L.).

The ultrastructural distribution of Mg2+ -dependent adenosine triphosphatase (ATPase) activity has been investigated in the salamander and frog pancreas by using glutaraldehyde fixations and a modified Wachstein-Meisel reaction medium. In both species the reaction product (lead phosphate) was found associated with the plasma membrane external side of all islet cell types (B-, A- and D-cells) and of acinar and ductular/centro-acinar cells. Except the apical pole of salamander acinar and centro-acinar cells, usually devoid of reaction, no preferential distribution of enzyme activity depending on endocrine or exocrine cell aspects could be observed. Other specific enzyme localizations included the mitochondria matrices, nucleoles, condensed nuclear chromatin, periaxolemmal spaces in nerve bundles and sometimes the cleft of neuro-glandular junctions. The occurrence of reaction deposits in connective tissue, in the cytoplasm of both islet and exocrine cells and in the nerve fiber axoplasm was considered as a possible diffusion artifact. The reaction intensity, but not its distribution, varied sensibly with the incubation period. 2-iodoacetamide and p-chlormercuribenzoic acid decreased the amount of reaction deposits at the level of all reactive sites and especially in mitochondria. The specificity of Mg2+ -ATPase demonstration in this paper is analysed taking into account several inherent shortcomings of the Wachstein-Meisel incubation medium and of the fixative. The different enzyme localizations, as well as their functional significances are discussed in relation with the findings of other authors.

Adenosine Triphosphatases↗
PubMed1979

Light and scanning microscopy of the taste organs and vascularization of the tongue of the spotted salamander, Salamandra salamandra (L.).

The mucosa of the spotted salamander tongue and its taste organs were investigated by means of light and scanning electron microscopy. The most striking feature of the salamander tongue is an almost complete lack of papillae which are replaced by long, radially disposed folds with linear arrays of taste organs along their ridges. In respect of morphology, the taste organs of the salamander occupy an intermediate position between the taste buds of Urodela and taste discs of Salientia. Scanning electron microscopic examination of microcorrosion casts of the blood vessels of the tongue has revealed that the structure of subepidermal capillary network reflects the topography of the tongue surface and the distribution of its taste organs. In the core regions of the folds the capillary loops accompanying gustatory receptors empty via their shorter, descending arms into the draining vessels, the initial segments of which retain a course parallel to that of the folds. In the few fungiform papillae the capillary vessels form single loops whose distal ends come to lie in the vicinity of taste discs.

Animals↗
PubMed1978

Ultrastructure of the liver cells in Salamandra salamandra (L.) in the end of Winter.

Following hibernation, most salamander liver cells undergo alterations. The liver cells containing the structure of their active period present a normal nucleus, glycogen granules disseminated throughout the entire cytoplasm and granular mitochondria with several peripheral cristae. Most cells, however, possess altered mitochondria, transformed into electron-dense masses, or clear vesicles with the possibility of digesting the ambient organelles. Other cells have clear vacuoles with similar digestive possibilities. The endoplasmic reticulum is poorly represented in the liver cells that have suffered advanced alteration. The nucleus of these cells is homogeneously granular. The sytoplasm is populated by electron-dense bodies and lipid vacuoles. The nucleolemma and plasmalemma are thickened. The pigmented cells, altered concomitantly with the liver cells, contain granular aggregates. Some of the pigmented cells exhibit electron-clear formations similar to the reflecting platelets of the iridocytes of the integument of lower vertebrates.

Animals↗
PubMed1977

Fine structural localization of glucose-6-phosphatase activity in the pancreatic islets of two amphibian species (Salamandra salamandra L. and Rana esculenta L.).

The ultrastructural distribution of glucose-6-phosphatase activity has been investigated in the salamander and frog pancreas. In the pancreas of salamander the enzyme was located in the A-cells, while in frog it occurred in all main types of islet cells B-, A-, and D-cells). As a rule, the reaction intensity was higher in the frog islet cells. No reaction was recorded in the exocrine pancreatic tissue of both species. The glucose-6-phosphatase activity was constantly detected in the lumen of rough endoplasmic reticulum and between the nuclear envelopes. Other enzyme localizations, observed especially in the A-cells of the salamander pancreas, were considered possible diffusion artifacts ro remnants of other phosphatase activity. The enzyme distribution in different types of islet cells, as well as its functional significance are discussed in relation to the findings of other authors.

Animals↗
PubMed2026

Comparative Transcriptomic Analyses Identify Candidate Genes for Convergent Reproductive Shifts in a Bimodal Viviparous Amphibian.

Shifts in reproductive mode represent key evolutionary innovations that shape species' life histories and evolutionary trajectories. Species showing bimodal reproductive strategies with multiple independent origins offer a rare opportunity to gain insights into the adaptive processes and mechanisms underlying convergent traits. The fire salamander, Salamandra salamandra, is the only amphibian exhibiting intraspecific variation in reproductive mode across multiple independent reproductive shifts, enabling investigation of the transition between larviparity (females give birth to aquatic larvae) and pueriparity (females give birth to fully developed terrestrial juveniles) within a single species and across different timescales. Pueriparity is an adaptive innovation that skips the aquatic larval stage, allowing individuals to exploit habitats with no available water bodies. The fire salamander is larviparous across most of its range, but pueriparity has evolved independently at least three times: once in the early Pleistocene within S. s. bernardezi in the mountains of northern Spain, and more recently on two land-bridge islands (NW Spain) inhabited by S. s. gallaica. To identify candidate genes associated with these distinct reproductive modes, we compared gene expression profiles of the uterus and oviduct of pregnant females across two independent evolutionary transitions using RNA-sequencing. We detected shared changes in maternal gene expression among pueriparous S. s. bernardezi and S. s. gallaica relative to their larviparous counterparts, in addition to differences unique to each independent evolutionary transition. Functional enrichment analyses indicated that differentially expressed genes were associated with reproductive timing, angiogenesis, and maternal signalling, consistent with the phenotypic differences observed in the uterine environment and embryonic development between the two reproductive modes. This study represents an important first step towards understanding the genomic basis of the evolution of pueriparity in a remarkable bimodal reproductive system, and provides transcriptomic resources and candidate genes for future research into the genomic architecture underlying this poorly understood adaptive trait.

Animals↗
PubMed1978

Experimental gynogenesis in the newt species Pleurodeles waltlii and P. poireti.

Eggs of diploid females of Pleurodeles waltlii, inseminated by genetically inactivated sperm of Salamandra salamandra, have been treated by heat-shock or increased hydrostatic pressure during the first hour of their development. The resulting viable gynogenetic individuals show different degrees of ploidy although they mostly are diploid. The use of females with a pericentric inversion as a marker chromosome allow the chromosomal constitution to be clarified. Eggs of females heterozygous for a recessive semilethal mutation (ascite caudale, ac) subjected to the same experimental treatment gave 50% ac/ac embryos. Experiments with Pleurodeles poireti gave the same results as those with P. waltlii. These observations prove that gynogenetic Urodeles can be produced in large numbers. In their offspring the detection of inherent or spontaneous recessive mutations is greatly facilitated.

Aneuploidy↗