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At least 19 recordsLinked to original sources
PubMed1978

Experimental hybridization within the genus Triturus (Urodela: Salamandridae). I. Spermatogenesis of F1 species hybrids, Triturus cristatus carnifex female x T. vulgaris meridionalis male.

The spermatogenesis of 9 F1 hybrids of Triturus cristatus carnifex female x T. vulgaris meridionalis male was studied in squash preparations of testicular fragments, treated by the C-staining method. The chromosome number of these hybrids was examined in spermatogonial metaphases and found to be diploid. The two parental sets were always recognized, which means that a regular, although heterospecific, amphimixis occurred (2n = nfemale + nmale). Meiotic prophase I is greatly altered owing to a failure of typical chromosome pairing and chiasma formation. At metaphase I and/or meta-anaphase I, the effects of the hybrid combination of the 2 specific parental sets are clearly visable. Most primary spermatocytes contain only univalents. A few show chromosome associations (bivalents, trivalents and, more rarely, quadrivalent chains) besides univalents. Such associations are of 2 types: (a) intragenomal associations = associations of 2 chromosomes by a terminal (a1) or subterminal chiasma (a2); (b) intergenomal associations = associations of 2 chromosomes by a terminal (b1) or subterminal chiasma (b2). Univalents segregate at random while the associations often lag on the equatorial plane or migrate entire to a spindle pole. Primary spermatocytes with chromosome multivalents can encounter greater difficulties in accomplishing the first cytokinesis. Secondary spermatocytes are numerically and qualitatively unbalanced; however, some of them undergo spermiogenesis and can give rise to a small number of sperms, generally abnormal and never united in bundles. --Problems related to the occurrence of "anomalous" chiasmata and of intra- and inter-genomal homologies are discussed.

Animals↗
PubMed1977

The effects of hydrocortisone and bacterial lipopolysaccharide on the anti-erythrocyte response in the spleens of adult Triturus viridescens.

The effects of hydrocortisone (HC) and bacterial lipopolysaccharide (LPS) have been tested separately and in combination, on the antigen-binding response of splenocytes of the newt. Triturus viridescens immunized with horse erythrocytes (HRBC). The timing of the presentation of each was made relative to when challenge with either low (0.0025%) or high (25%) doses of the immunogen (HRBC) was effected. Our results showed inhibition of both low and high dose responses by HC and additionally suggested that the helper-cell population of the newt is HC-sensitive. LPS given four days prior to antigen challenge initiated the generation of antigen-binding cells which enhanced the low, but not the high dose response. The use of LPS in conjunction with HC provided suggestive evidence that those LPS stimulated cells which had enhanced the low immunogen dose antigen-binding cell response were HC-resistant. Thus LPS may stimulate a non-helper cell population in the newt which is HC-resistant. The use of these two immunologic probes has provided supportive evidence on the heterogeneity of the lymphoid population of the newt, Triturus viridescens.

Animals↗
PubMed1977

Histological, immuno- and enzyme-histochemical investigations on the adenohypophysis of the urodeles, Mertensiella caucasica and Triturus cristatus and the caecilian, Chthonerpeton indistinctum.

The pituitary glands of two urodelan species (Mertensiella caucasica, Triturus cristatus) and one one caecilian species (Chthonerpeton indistinctum) were examined with histological (Alcian blue, Brookes' trichrome stain), enzyme histochemical (acid phosphatase, alpha-naphthylacetate-esterase, acetylcholinesterase) and immunofluorescence techniques (anti-carp GTH, anti-ovine prolactin, anti-synthetic alpha-MSH). In the pituitary gland of Mertensiella and Triturus six chromophilic cell types could be distinguished. A strong fluorescence was observed in the MSH-, GTH- and TSH-cells. In the pituitary gland of Chthonerpeton only five chromophilic cell types could be distinguished: in the rostral part of the pituitary gland the B3-cell; in the basal region of the central area the B2-cell; dorsocaudally the B1-cell. The acidophilic cells were found in the central and caudal part of the pars distalis. The basophils of the pars intermedia could be observed in the dorsocaudal part of the pituitary gland surrounding the neurohypophysis. All acidophilic cells showed a strong immunofluorescence with anti-ovine prolactin (LTH).

Acetylcholinesterase↗
PubMed1992

Plasma testosterone and 17 beta-estradiol concentrations, and aromatase activity, during courtship in male Triturus carnifex.

Plasma testosterone and 17 beta-estradiol were monitored during the main phases of male Triturus carnifex courtship. "Inactive" males showed higher levels of testosterone with respect to those found during the various courtship phases. Estradiol was low in "inactive" males, and it reached the highest values at the beginning of the courtship. In addition aromatase activity was higher in the brain of the newts at the beginning of the courtship. These findings seem to support the "aromatization hypothesis" in Triturus carnifex.

Animals↗
PubMed1992

Relationships among mammalian gonadotropin-releasing hormone, prostaglandins, and sex steroids in the brain of the crested newt, Triturus carnifex.

The present study was carried out to evaluate the in vitro brain release of prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), androgens, and 17 beta-estradiol in male and female crested newt, Triturus carnifex, during three different periods of the annual sexual cycle; in addition, the effects of mammalian gonadotropin-releasing hormone (mGnRH), PGF2 alpha, and PGE2 on prostaglandins and steroids release by the brain were evaluated during the same periods. In brain incubations of both sexes, PGF2 alpha and estradiol were higher during postreproduction, while PGE2 and androgens were higher during reproduction. In both sexes, mGnRH increased PGF2 alpha and estradiol during postreproduction, and PGE2 during reproduction; PGF2 alpha increased estradiol secretion during postreproduction. Only in the male, did both mGnRH and PGE2 increase androgens during reproduction. It could be suggested that in Triturus carnifex, the regulation of the reproductive activity in the central nervous system (CNS) depends on the relationships among mGnRH, prostaglandins and steroids. In particular, PGF2 alpha and PGE2 seem to play different roles in the CNS of the newt: PGF2 alpha is involved in the postreproductive processes, through estradiol secretion, while PGE2 in the reproductive ones (through androgens secretion?).

Androgens↗
PubMed1977

A comparative cytochemical study of the yolk platelets in the growing oocytes of Triturus cristatus and Rana esculenta.

Recent cytochemical techniques for the detection of proteins, neutral and acid mucopolysaccharides, lipids and phospholipids in the yolk platelets of the growing oocytes of Rana esculenta and Triturus vulgaris are employed. Cytochemical analysis showed that the yolk in the form of granules or platelets, in the constituting itself the most prominent cytoplasmic inclusion of amphibian eggs, contains a protein moiety consisting of individual typical amino acids lacking tryptophan in Triturus, a carbohydrate fraction consisting of neutral mucopolysaccharides distributed in the superficial layer of each platelet, and phospholipids, phosphoproteins and lipoproteins which are present only in the main body of the same platelets. The different amino acid composition indicated a protein heterogeneity which could be connected with the tissue incompatibility of the transplantations when these last were effected between the orders Urodela and Anura. The different protein composition of the yolk also can be reflected at the species-specific level. The cytochemical data are further reviewed with the mode of utilization of the yolk platelets.

Amino Acids↗
PubMed1977

Early steroid metabolism in Xenopus laevis, Rana temporaria and Triturus vulgaris embryos.

Embryos of Xenopus laevis, Rana temporaria and Triturus vulgaris exposed to radioactive pregnenolone have been found to convert it to progesterone. Incubations with radioactive progesterone showed that it was actively metabolized by oocytes and embryos. In Xenopus incubations progesterone was converted to 5alpha-pregnane-3,20-dione, 17alpha-hydroxy-4-pregnen-3-one, 4-androstene-3,17-dione and 17alpha-20alpha-dihydroxy-4-pregne-3-one, indicating 5alpha-reductase, 17alpha-hydroxylase, 19-20-desmolase and 20alpha-hydroxylase activities. In oocytes of Triturus and Rana no evidence of 19-20-desmolase was found. In Rana oocytes were also not evidence of 17alpha-hydroxylase activity. All identified activities except 20alpha-hydroxylase were common to embryos of all three species. It is suggested that the steroid enzyme activities present in the embryos are not solely derived from the oocytes but synthentized during early development. Possible meaning of this kind of metabolism during differentiation remains open.

Animals↗
PubMed1975

[Evolution of xenografts of embryonic gonads and juvenile ovaries from Ambystoma mexicanum Shaw, transplanted into Triturus alpestris Laur].

Gonad primordium of Ambystoma mexicanum when grafted at tail-bud stage on Triturus alpestris is indefinately tolerated. Testis or ovaries derived from those grafted embryonic gonads follow their differentiaion and reach sexual maturity. Axolotl juvenile ovaries transplanted in Triturus alpestris are also tolerated; the ovocytes achieve the entire vitellogenesis but are not able to be laid.

Ambystoma↗
PubMed1976

Electron microscopic stldy of the developing lateral-line organ in the embryo of the newt, Triturus pyrrhogaster.

The morphological sequence of events occurring in the development of the lateral-line organ was investigated in the embryo of the newt, Triturus pyrrhogaster, by means of electron microscopy. Six stages of development have been defined for convenience of description. The primordium of the lateral-line organ migrating from the pre- and post-auditory placodes is segmented into a small cell mass accompanied by a few Schwann cells enveloping nerve fibers. In the clump of cells of the lateral-line primordium, three kinds of cells are already distinguished by different degrees of darkness, i.e., dark, light and slightly dark cells (stage I). Both clump and Schwann cells enter the epidermis together (stage II). The two groups of cells are separated by the inner layer of the epidermis (stage III). The organ-forming cells elongate and the inner layer of the epidermis separates the Schwann cells from the clump (stage IV). The apexes of organ-forming cells are exposed out of the epidermis (stage V). The lateral-line organ is almost matured. The dark cells correspond to type II of the supporting cells, the light cells correspond to type I of the supporting cells and the slightly dark cells correspond to the receptor cells because of the existence of cilia and a cuticular plate. The afferent nerve endings are found on the basal surface of the receptor cell (stage VI).

Animals↗
PubMed1975

Regeneration of the retina in the adult newt, Triturus cristatus, following surgical division of the eye by a limbal incision.

The regeneration of a retina in adult Triturus cristatus, following surgical division of the eye by a limbal incision, was studied. In agreement with recent reports, it was found that the regenerating retina is dervied from two sources; the retinal pigment epithelium and the pars ciliaris retinae. However, following a limbal incision, most of the retina appears to be derived from the retinal pigment epithelium in the posterior part of the eye. An unexpected finding of this study was that large cystlike spaces form in the fundal regions of the eye, between the regenerating retina and the retinalpigment epithelium. These spaces appear between five and eight days post-operative and persist long enough (25 to 30 days postoperative) to disrupt the fundal portion of the rengenerating retina and to cause it to lag behind the rest of the regenerate, in its development. The relationship of these observations to the genesis of positional markers in the regenerating retina is discussed.

Animals↗
PubMed1975

Non-glial phagocytes within the degenerating optic nerve of the newt (Triturus viridescens).

Two non-glial phagocytes were found to participate along with ependymoglial cells in Wallerian degeneration of the severed optic nerve of the newt (Triturus viridescens). The first type of non-glial cell (polymorphonuclear phagocyte) was positively identified as a neutrophil and participates in the early stages of degeneration. Cells of this type make a brief appearance, reaching a peak by the second postoperative day (2 p.o.d.), and quickly diminish until few can be found by 4 p.o.d. Neutrophils invade the degenerating optic nerve from surrounding connective tissue spaces, most likely, through channels which penetrate the nerve parenchyma. The second type of non-glial cell is an invading mononuclear phagocyte which exhibits characteristics of microglial cells reported in other vertebrate species. Such cells appear in the nerve much later than the neutrophils and towards the end of Wallerian degeneration (6-10 p.o.d.). Their mode of entry and exit appears to be the same as that reported for neutrophils. The neutrophils and microglial-like, mononuclear phagocytes may serve to supplement the histolytic action of the ependymoglial cells, picking up scattered fragments of degenerating myelin and axons.

Animals↗
PubMed1977

The effect of nerve growth factor and limb regeneration on the spinal and sympathetic ganglia of Triturus.

In Triturus administration of NGF causes hypertrophy of neuronal perikarya of third dorsal root ganglia and post-subclavian sympathetic ganglia. Two classes of neurons were characterized cytologically in the third dorsal root ganglia. Some evidence is presented which indicates that Class I neurons respond more vigorously to NGF. It is suggested that Class I neurons are similar to the medio-dorsal neuroblasts of chick embryos in their response to NGF. Forelimb amputation did not cause neuronal hypertrophy in either third dorsal root ganglia or post-subclavian sympathetic ganglia. The incorporation of (3H)-uridine increases to a highly significant extent in third dorsal root ganglia following NGF treatment or limb amputation. When NGF treatment and limb amputation were combined, no further increase in (3H)-uridine incorporation was noted. This suggests that RNA synthesis is maximally stimulated by either NGF treatment alone or limb amputation alone.

Amputation, Surgical↗
PubMed1975

Observations on peroxisomes in interrenal (adrenocortical) cells of Triturus cristatus and Salamandra salamandra (Urodele Amphibians).

Intracellular organelles (average diameter: 0.3 mu) similar to peroxisomes were observed in the interrenal cells of Triturus cristatus and Salamandra salamandra. Their peroxisomal nature was demonstrated by incubating tissue sections in alkaline 3,3-diaminobenzidine. Oxidation of diaminobenzidine, a characteristic feature of peroxisomes, was observed. These organelles are devoid of a central nucleoid and are surrounded to various degrees by profiles of the smooth endoplasmic reticulum. The matrix of these organelles is sometimes in direct communication with the inside of the smooth tubules. These relationships suggest a possible origin of the peroxisomes from the smooth endoplasmic reticulum.

Adrenal Cortex↗
PubMed1976

Osmium zinc iodide staining of Golgi elements in oocytes of Triturus cristatus.

Developing oocytes of the newt Triturus cristatus were studied in order to clarify the role played by the Golgi apparatus in the formation of yolk. The cytochemical method used for this purpose was that of Maillet (1968) which employs an Osmium Zinc Iodide (OZI) complex. Previtellogenic oocytes reveal a pattern of OZI staining only after hormonal (HCG) stimulation, following which both the Golgi apparatus and the multivesicular bodies are stained. Vitellogenic oocytes taken from non-hormonally stimulated females reveal OZI deposits in a number of vesicles peripheral to the Golgi apparatus as well as within the superficial layer of the forming yolk platelets. Following hormone stimulation, many of the Golgi apparatus located in the central ooplasm of vitellogenic oocytes have all their cisternae blackened by the OZI deposits; other apparatuses,more peripherally located, remain essentially unchanged in their staining pattern. Further, a large number of OZI stained vesicles becomes visible in the vicinity of the Golgi apparatus and within the superficial layer of the forming yolk platelets. The present findings are interpreted as indicating the occurrence of fusion between Golgi derived vesicles and forming yolk platelets. It is also suggested that the vesicles in question function as carriers of Golgi produced enzymes which are presumably required to accomplish the final elaboration of the yolk material.

Animals↗
PubMed1978

Chromosome location of the ribosomal RNA genes in Triturus vulgaris meridionalis (Amphibia, Urodela).

The mitotic chromosomes of six specimens from Triturus vulgaris meridionalis have been examined by both in situ hybridization with 3H 18S + 28S rRNA and AS-SAT staining method. The results of these two sets of experiments can be summarized as follows: 1) in each specimen the NORs and the additional ribosomal sites, which react positively to in situ hybridization with 3H 18S + 28S rRNA, are also stained by silver; 2) other chromosomal regions, which do not hybridize in situ with 3H 18S + 28S rRNA, are on the other hand stained by the AS-SAT method. These latter AG-positive sites show a species-specific pattern of chromosomal distribution.

Animals↗
PubMed1977

Chromosome location of the ribosomal RNA genes in Triturus vulgaris meridionalis (Amphibia, Urodela). II. Intraspecific variability in number and position of the chromosome loci for 18S + 28S ribosomal RNA.

Ribosomal genes have been localized on mitotic and lampbrush chromosomes of 20 specimens of Triturus vulgaris meridionalis by in situ hybridization with 3H 18S + 28S rRNA. The results may be summarized as follows: 1) each individual shows positive in situ hybridization at the nucleolus organizing region (NOR) on chromosome XI; 2) in addition, many specimens exhibit a positive reaction in chromosomal sites other than the NOR (additional ribosomal sites); 3) the chromosomal distribution of the additional sites appears to be identical in different tissues from the same specimen and to follow a specific individual pattern; 4) the additional ribosomal sites are preferentially found at the telomeric, centromeric or C-band regions of the chromosomes involved.

Animals↗