Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| sino-atrial block and atrioventricular block obtained simultaneously with the second stannius ligation in the heart of emys orbicularis. | 1948 | 18872664 | |
| [contributions to ontogenesis of the hypophysis of testudo graeca and emys orbicularis, with special consideration of its relations to prechordal plate, chorda and intestinal roof]. | 1956 | 13468674 | |
| [a lung tumor in a turtle, emys orbicularis]. | 1963 | 14064694 | |
| physiological role of coronary constriction in the tortoise (emys orbicularis l.). | 1964 | 5855852 | |
| projection of optic fibers to visual centers in a turtle (emys orbicularis). | 1967 | 6036113 | |
| [vestibular reactions caused by acceleratory stimulation in emys orbicularis (tortoise)]. | 1967 | 5298962 | |
| [the evacuatory ducts of bile and pancreatic juice in emys orbicularis l]. | 1967 | 5587850 | |
| [some details concerning the structure of the "lamina terminalis" of the cheloniid "emys orbicularis"]. | 1967 | 5594417 | |
| immunoglobulin production in the european pond tortoise, emys orbicularis, immunized with serum protein antigens. | 1968 | 4173673 | |
| [the restoration cycle of driving reaction potentials in the cortex of the cerebral hemispheres of the marsh turtle (emys orbicularis)]. | 1968 | 5757789 | |
| [retino-tegmental projections in the swamp turtle (emys orbicularis)]. | 1969 | 5370480 | |
| [cytoarchitectonics and neuron composition of the tegmen of the midbrain in the turtle (emys orbicularis)]. | 1970 | 5489752 | |
| [sex ratio in the embryos of 2 chelonians (testudo graeca l. and emys orbicularis l.) born of artificially incubated ova]. | 1971 | 4997326 | |
| [function of the cerebellum and the forebrain in the behavior of turtles (emys orbicularis and clemmys caspica)]. | 1972 | 5086131 | |
| [temperature effects on the development of genital glands in the embryos of 2 chelonians, emys orbicularis l. and testudo graeca l]. | 1972 | 4622404 | |
| [synthesis activities in the apical epiblastic crest of forelimb anlagen in turtle (testudo graeca and emys orbicularis l.) embryos; histological and autoradiographic study]. | 1972 | 4622080 | |
| [ultrastructure of functionally different skeletal muscle fibers of the bog turtle emys orbicularis]. | 1973 | 4362315 | |
| [autoradiographic study of the anterior limb-bud development in two species of chelonians (testudo graeca l. and emys orbicularis l)]. | 1973 | 4717984 | |
| receptive fields of the mesencephalic visual center of the turtle (emys orbicularis). | 1973 | 4698117 | |
| [changes in the delta 5-3 beta-hydroxysteroid dehydrogenase enzymatic activity in the genital glands of emys orbicularis l embryos (chelonians) according to incubation temperature]. | 1973 | 4266567 | |
| [experimental study on the role of the somites during the early stages of development of the front limbs of the embryo of the chelonian emys orbicularis l]. | 1974 | 4463211 | |
| [electron microscopic study of degenerative changes in the nucleus globosus of the turtle emys orbicularis following tectectomy]. | 1974 | 4838217 | |
| [pone tortoises (emys orbicularis) as a possible source of leptospira infection]. | 1974 | 4281241 | |
| [morpho-functional changes in the tegmentum mesencephali of turtles following enucleation]. | morpho-functional changes in the mesencephalic centre of the turtle (emys orbicularis l.) were studied during optic nerve degeneration. it was observed that synaptic terminals in this centre undergoing the "dark" degeneration are associated with myelinated optic fibres and terminals undergoing the "light" one are associated with unmyelinated fibres. the first low amplitude component of the evoked potential disappears with degeneration of myelinated fibres of large diameter during the "dark" dege ... | 1975 | 1207808 |
| ultrastructure of the joint receptors of the tortoise (testudo graeca. emys orbicularis). | the ultrastructure of the spray-like ramified encapsulated corpuscles with the primitive inner core from the joint capsules of the large limb joints of the tortoise (testudo graeca and emys orbicularis) was examined. each of the branches of the receptor consists of three components. through the middle of the receptor branche runs the nerve terminal, containing in the receptor matrix numerous mitochondria, tiny light vesicles and neurofilaments and neurotubules running in the axial way. the nerve ... | 1975 | 1234809 |
| [the problem of yawning in reptiles]. | yawning in reptiles was investigated in field observations of various lizard and tortoise species and in laboratory experiments with the tortoises testudo h. hermanni and emys orbicularis. in the experiments the animals' reactions to various conditions of temperature, air o2 and co2 content, fatigue and hunger, were tested. yawning and related or similar motor patterns are described and discussed. | 1975 | 1146423 |
| ciliated neurons and different types of synapses in anterior hypothalamic nuclei of reptiles. | the magnocellular paraventricular and supraoptic nuclei and the parvocellular preoptic and periventricular nuclei have been studied by light and electron microscopy in emys orbicularis, lacerta agilis and elaphe longissima. the ultrastructure of cerebrospinal fluid (csf)-contacting neurons was described in the preoptic and periventricular nuclei of emys and lacerta species. single 9 x 2 + 0 cilia similar to those of the csf-contacting dendritic terminals were found on perikarya of non csf-contac ... | 1976 | 991258 |
| [laminar analysis of neuronal ultrastructure in the midbrain tectum of the steppe turtle]. | a layer-to-layer study of the neuronal ultrastructure in the mesencephalic optic centre of t. horsfieldi has been made, the results being compared to those of similar experments with emys orbicularis l. neurons of the efferent type (layers iv, v), in contrast to short axon elements (layers, i, 22) are characterized by a greater amount of cytoplasm and by a variety of cytoplasmatic organelles. a few morphological types of neurons are distinguished: light, dark and neurons with a light nucleus and ... | 1976 | 1014100 |
| blood proteins in turtles (testudo hermanni, emys orbicularis and caretta caretta). | 1976 | 9229 | |
| [glucose-6-phosphatase activity of the pia mater of several representative vertebrates]. | studies have been made on the glucose-6-phosphatase activity in the pial matter of the lamprey lampetra fluviatilis, carp cyprinus carpio, frog rana temporaria, tortoises emys orbicularis and testudo horsfieldi, hen, rabbit and cat. the data obtained not only confirmed earlier observations on extremely high activity of the enzyme in lamprey's brain, but also demonstrated high activity of glucose-6-phosphatase in the pial matter of other vertebrates, especially in tortoises. | 1977 | 197748 |
| [comparative characteristics of the dendritic spines of the 3 chief zones of the forebrain cortex of steppe and bog turtles]. | a comparative study of dendritic spines in the principal cortical regions of the forebrain was performed for two turtle species by the golgi and electron-microscopy methods. common features of spines were revealed for every cortical region of both turtle species. distribution peculiarities in the proximal, middle and distal sections of the spines, as well as their density, shape, length and ultrastructure were taken into account. apart from similar features for two turtle species, there are some ... | 1977 | 859669 |
| [early developmental stages of the hindlimbs in chelonian embryos testuda graeca l. and emys orbicularis l]. | 1977 | 615552 | |
| [transthalamic conduction of visual impulses into the cortex and subcortical portions of the turtle forebrain]. | thalamic structures relaying impulses originating from optic stimulation of the retina and electric stimulation of the tectum on the way to the general cortex, hyperstriatum dorsal ventricular ridge and striatum were studied in turtles emys orbicularis. anodal polarization of the n. rotundus temporarily, and the lesion of this nucleus irreversibly, suppressed the main negative component of responses evoked by tectal stimulation and light flashes in the dorsal ventricular ridge without affecting ... | 1977 | 927595 |
| [topography and cytoarchitectonics of the main cortical zones of the turtle forebrain]. | the description of cytoarchitectonics and topography of the three principle cortical zones of the forebrain of emys orbicularis reveals that the cortical structures in the species are precisely distinguished with respect to their neuronal characteristics, density and the situation of cellular elements. emys orbicularis occupies an intermediate position among the species of the order chelonia described in the literature as regards the level of development of the forebrain cellular structures. emy ... | 1977 | 597065 |
| [effects of raised and lowered incubation temperatures on the sexual differentiation in the embryos of emys orbicularis l. (chelonien)]. | eggs of emys orbicularis l. were incubated at 18 and 19 degrees 5c during the period of sexual differentiation of the gonads of the embryos; genital glands of testicular structure and retrogressed müllerian ducts were observed in all cases, like in the embryos issued from eggs incubated at 25 +/- 1 degrees c and 27,5 +/- 0,5 degrees c. on the contrary, the sexual phenotype is female in all the embryos which developed at 35 degrees c, as it is the case between 29 and 30 degrees c. | 1978 | 417845 |
| [several features of the metabolism of the fast and slow muscles of emys orbicularis tortoises]. | in skeletal muscles of the tortoise e. orbicularis, studies have been made on the content of glycogen, lactic acid, on the activity of glucose-6-phosphatase and phosphorylase. histochemical studies were made on the lipid content. experiments were performed on fast and slow bundles from mm. iliofibularis, testo cervicalis and retractor capitis. for comparison, the same indices of carbohydrate metabolism were investigated in fast m. plantaris and slow m. soleus of rats. in rats, slow muscles exhib ... | 1978 | 213913 |
| [comparative study of the fatty acid composition of glycerophosphatides from whole vertebrate brain and portions of it]. | fatty acids of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and monophosphoinositide were studied in the whole brain, in the forebrain and the brain stem in the frog rana temporaria, tortoise emys orbicularis, hen and cat. every family of phospholipids (pl) possesses a characteristic fatty acid pattern irrespectively of the brain part. there are regular topologic differences in the fatty acid composition of pl, namely the relative amount of saturated and polyenoic acids is h ... | 1978 | 216195 |
| [parasites of fresh water turtles in tunisia]. | a survey work during 1974-75 on the parasites of aquatic turtles of tunisia, twenty one specimens (9 males and 12 females) were captured in the watercourses of the northern area of tunisia and dissected in the institut pasteur of tunis. these turtles belong to the species; clemmys caspica var. leprosa and emys orbicularis (l. 1758). the following parasites were recovered from these turtles: trematodes: polystomoides tunisiensis and telorchis temimi (gonzalez and mishra, 1977) and t. solivagus (o ... | 1978 | 756699 |
| [use of mouse h-y antiserum for the determination of genetic sex in emys orbicularis l. (testudines, emylidae)]. | 1979 | 111857 | |
| [a comparative study of the fatty acid composition of the sphingomyelins in the whole brain and its parts in vertebrates]. | the fatty acid composition of sphingomyelin (spm) was studied in the total brain, the forebrain and the brain stem in frogs (rana temporaria and rana ridibunda), the tortoise (emys orbicularis), the hen and the cat. a typical fatty acid pattern of spm was revealed irrespectively of the brain part examined. regular differences in fatty acid composition of spm between various brain parts were found irrespectively of the level of development of the nervous system. it may be concluded that correspon ... | 1979 | 95835 |
| comparative characterization of the basic forebrain cortical zones in emys orbicularis (linnaeus) and testudo horsfieldi (gray). | the neuronal and synaptic organization of forebrain basic cortical zones in testudo horsfieldi and emys orbicularis and their dendritic spines have been studied using nissle, golgi and electron microscopic methods. it has been shown by comparison of the results that the two spicies have marked differences in the structural organization of the forebrain cortical zones. the cortical formation in testudo horsfieldi is different from that of emys orbicularis in a greater diversity of neuronal types, ... | 1979 | 536589 |
| [tegmento-thalamic interrelationships in turtles]. | in immobilized, weakly anesthetized with chloralose turtles emys orbicularis the focus of evoked potentials and the largest number of single unit responses to the stimulation of the mesencephalic tegmentum were revealed in the ventral thalamic region (a heterosensory zone with dominating somatic modality). an incomplete separation of latero- and mediotegmental projections was observed in dorsal and ventral subdivisions of the ventral thalamic region, respectively. the tegmental stimulation coinc ... | 1980 | 7374852 |
| [morphological study of the medial and posterior hypothalamus projections to the forebrain in turtles]. | ascending connections of the middle and posterior hypothalamic structures (n. ventromedialis, n. periventricularis arcuatus pars ventralis, n. mammillaris medialis) have been studied in the emys orbicularis by means of anterograde degeneration and electron microscopic techniques. it has been demonstrated that the hippocampal cortex (its dorsomedial and dorsal parts) is the main cortical zone of projections for the nuclear formations mentioned above. their projections are ipsilateral and occupy t ... | 1980 | 7447727 |
| [tegmento-telencephalic interactions in turtles]. | electrophysiological characteristics of tegmental projections in the forebrain were studied in immobilized slightly chloralose anesthetized turtles emys orbicularis. the main zone of tegmental representation was found in the striatum where the most short-latent evoked potentials were recorded and the largest number of single units responding to tegmental stimulation was concentrated in comparison both with the dorsal ventricular ridge and general cortex. it is shown that laterotegmental projecti ... | 1980 | 7402410 |
| [development of the adrenergic innervation of the atrioventricular valves of certain vertebrates]. | adrenergic innervation of the atrioventricular valves in the carp cyprinus carpo, frog rana temporaria, tortoise emys orbicularis, hens and albino rats has been investigated by histochemical glyoxylic technique. it was shown that the adrenergic innervation of cardiac valves becomes more intense and more complex during progressive evolution of cardio-vascular activity. adrenergic nerves realize the connection between annullus fibrosus, valve, chordal tendineal and papillary muscles. chromaffin ce ... | 1980 | 6967660 |
| [glycogen content and activities of phosphorylase and glucose-6-phosphatase in the fast and slow muscles of representatives of different classes of vertebrates]. | studies have been made on glycogen content as well as on the activity of phosphorylase and glucose-6-phosphatase in fast and slow muscles from representatives of 6 classes of vertebrates (lampetra fluviatilis, cyprinus carpio, rana temporaria, rana ridibunda, emys orbicularis, hen, rat). glycogen level and glucose-6-phosphatase activity are either higher in slow muscles, or practically identical in both types of muscles (glucose-6-phosphatase is absent from the fast muscles of hens and rats). on ... | 1980 | 6247864 |
| light- and electron-microscopic demonstration of immunoreactive opsin in the pinealocytes of various vertebrates. | an antibody to opsin isolated from rod outer segments of the frog retina was applied in light- and electron-microscopic immunocytochemical studies to the pineal organ of various vertebrates (cyprinus carpio, carassius auratus, rana esculenta, emys orbicularis, pseudemys scripta elegans, lacerta agilis and viridis. gallus domesticus, columba livia, melopsittacus undulatus, serinus canaria, taeniopyga punctata, didelphis virginiana, erinaceus roumanicus, myotis myotis, rabbit, rat, cat). | 1981 | 6458362 |
| [comparative study of the neuronal and synaptic organization of the tectum mesencephali in the caspian (clemmys caspica gmel.) and pond (emys orbicularis l.) tortoises]. | the neuronal and synaptic organization of tectum opticum was studied in two species of tortoises (clemmys caspica gmel, and emys orbicularis l.) by means of nissl, golgi and electron microscopical methods. the clemmys caspica tectum differs from that of the emys orbicularis in a greater diversity of neuronal composition; a greater variety and quantity of cells with short axons, the presence of neurons with relatively short dendrites, in a greater relative thickness of the upper and deep systems ... | 1981 | 7316786 |
| erythropoiesis and haemoglobin ontogeny in the turtle emys orbicularis l. | the erythropoietic sites and developmental patterns of haemoglobins have been investigated during ontogeny of emys orbicularis. the yolk-sac blood islands seem to be the unique erythropoietic site during most of embryonic life. bone marrow haemopoiesis is first observed in young turtles aged one year. the cortical haemopoietic layer of the liver appears involved mainly in granulopoiesis. there is no morphologically well-defined series of primitive or definitive erythrocytes. rather there is a gr ... | 1981 | 7276806 |
| determination of temperature sensitive stages for sexual differentiation of the gonads in embryos of the turtle, emys orbicularis. | in order to determine the temperature sensitive stages for sexual differentiation of the gonads in emys orbicularis, eggs of this turtle were shifted at different stages of embryonic development from the male-producing temperature of 25°c to the female-producing temperature of 30°c and reciprocally. based on the series of developmental stages described by yntema ('68) for chelydra serpentina, temperature begins to influence sexual differentiation of emys orbicularis at stage 16, a stage in which ... | 1981 | 30114859 |
| gonadal steroid levels in the turtle emys orbicularis l.: a preliminary study in embryos, hatchlings, and young as a function of the incubation temperature of eggs. | 1982 | 7106557 | |
| ultrastructure investigations into the impulse-generating centre in the heart of the european pond turtle (emys orbicularis). | 1982 | 7113340 | |
| h-y antigen expression in temperature sex-reversed turtles (emys orbicularis). | h-y antigen has been used as a marker for the heterogametic sex and is assumed to be an organizing factor for the heterogametic gonad. in the turtle emys orbicularis, h-y antigen is restricted to the female cells, indicating a female heterogamety (zz/zw) sex-determining mechanism. moreover, the sexual differentiation of the gonads is temperature sensitive, and complete sex reversal can be obtained at will. in this framework the relationships between h-y antigen, temperature, and gonadal phenotyp ... | 1982 | 7128977 |
| immunoreactive opsin in the pineal organ of reptiles and birds. | the presence of opsin was investigated with light microscopic immunocytochemistry in pinealocytes of reptiles and birds (emys orbicularis, pseudemys scripta elegans, lacerta agilis et viridis, gallus domesticus, columba livia, melopsittacus undulatus, serinus canaria, taeniopyga punctate). the outer segments of pinealocytes selectively bound antiopsin antibody as revealed by indirect immunocytochemical techniques, indicating the occurrence of a rhodopsin-like photopigment in these structures. th ... | 1982 | 6213109 |
| [connections of the thalamic and telencephalic centers of the auditory system in turtles]. | in the turtles emys orbicularis and testudo horsfieldi connections of the thalamic (n. reuniens) and telencephalic (medio-ventral part of the dorsal ventricular edge--dve) centers of the auditory system have been revealed by means of the retrograde and anterograde horseradish peroxidase (hp) transport method. at a local hp administration into the n. reuniens, the labelled neurons are detected bilaterally in the midbrain: in the auditory center (n. centralis of the torus) and predominantly in the ... | 1983 | 6661054 |
| [pathways in the dorsomedial hippocampus of the turtle]. | in tortoises (testudo horsfieldi gray) and in pond turtles (emys orbicularis l.) rostral portions connections of the dorsomedial hippocamp with various structures of the forebrain and the diencephalon have been studied. reciprocal connections of the hippocamp with the olfactory bulb have been revealed by means of the horseradish peroxidase method. other olfactory centers of the hemisphere (anterior olfactory nucleus, olfactory tubercle, bandaletta diagonalis (broca) nucleus and medial nucleus of ... | 1983 | 6838385 |
| the embryonic development of the cortical plate in reptiles: a comparative study in emys orbicularis and lacerta agilis. | from the earliest stage of its ontogenesis, the mammalian cerebral cortex displays a remarkable cytoarchitectonic organization, with its neurons oriented radially within the cortical plate (cp). it is not known whether this radial organization of cortical neurons is characteristic of every cerebral cortex or whether it reflects a progressive phylogenetic acquisition. in order to study this question, the embryonic development of the cortex has been examined in reptiles, where it is the most primi ... | 1983 | 6863592 |
| absence of purinoceptors in the heart of the turtle (emys orbicularis). | the effects of adenosine, adenosine 5'-triphosphate (atp), a slowly degradable atp analogue beta,gamma-methylene atp (appcp) and a degradation resistant atp analogue alpha,beta-methylene atp (apcpp) were examined on the turtle heart. adenosine, atp, appcp and apcpp had no effect on the rate or force of contraction of either the atrium or ventricle. the effects of acetylcholine and noradrenaline were also examined on the turtle heart. acetylcholine decreased the force and rate of contraction of t ... | 1983 | 6140104 |
| [contacts of the basal processes of the visual cone cells in the outer plexiform layer of the sensory membrane of the eyeball in turtles]. | in two tortoise (agrionemys horsfieldi gray, testudo graeca l.) and three turtle (emys orbicularis l., clemmys (mauremys) caspica gmel, tryonix sinensis wieg) species, contacts of basal processes (synaptic peduncles of the cone cells) have been studied electron microscopically. their ultrastructure and peculiarities in organization of specialized junctions between each other and with other neural elements are described. the interreceptory contacts revealed are considered to be of one of the gap ... | 1983 | 6661055 |
| transplantation of turtle embryonic thymus into quail embryo: colonization by quail cells. | turtle (emys orbicularis l.) embryo thymuses grafted in the somatopleure or onto the quail embryo chorioallantoic membrane developed in these heterotopic sites for 2-12 days. when the thymus was removed from embryos at early stages such that no thymocytes were yet present during normal development, epithelial cells with mitoses were observed in the explants but no turtle thymocytes developed whatever the duration of explantation. an extrinsic origin of lymphoid precursor cells can explain such r ... | 1983 | 6606698 |
| retinotectal system of the tortoise, testudo horsfieldi, gray (morpho-functional study in the norm and after enucleation). | the optic nerve and mesencephalic optic centre (tectum opticum, to) of the tortoise, testudo horsfieldi, gray, in the norm and after the enucleation have been studies using golgi's method, electron microscopy and the electrophysiological technique. the optic nerve comprises about 400,000 fibres represented by two classes of axons: myelinated (10%) and unmyelinated (90%). the diameters of the former vary within 0.3-3 mum, of the latter within 0.3-1.1 mum. the neurogramms of the optic nerve contai ... | 1984 | 1021601 |
| connections of the mesencephalic, thalamic and telencephalic auditory centers in turtles. some structural bases for audiosomatic interrelations. | the organization of auditory projections at the mesencephalic, thalamic and telencephalic brain levels was studied utilizing the method of horseradish peroxidase (hrp) transport in two species of the turtle--emys orbicularis and testudo horsfieldi. it was shown that the torus semicircularis receives bilateral afferents from the brain stem auditory centers. they arise predominantly from the contralateral cochlear nuclei, the ipsilateral superior olive, the dorsal and ventral nuclei of the lateral ... | 1985 | 2410486 |
| effects of picrotoxin on the turtle's electroretinogram under different background illumination. | the effect of 0.4 mm solution of picrotoxin (pt) on the electroretinogram (erg) of isolated eyecup preparations of turtle (emys orbicularis) was investigated under two different backgrounds (ib)--scotopic (0.009 lx) and mesopic (9 lx). the test stimulus intensity was 46 lx. an increase of the amplitudes of all erg waves was observed after pt application. the relative increase of the d-wave was the most pronounced one and was similar under the two ib. the relative increase of the b-wave, however, ... | 1986 | 3020874 |
| neurogenesis in reptilian cortical structures: 3h-thymidine autoradiographic analysis. | histogenesis was studied in forebrain cortical areas of two reptiles, emys orbicularis and lacerta trilineata, by using tritiated thymidine autoradiography. four areas were considered: the dorsomedial, the general (dorsal), and the lateral cortices, and the dorsal ventricular ridge (dvr). the bulk of neurogenesis in these four pallial fields proceeds within a short period of 8-9 days, between developmental stages 15 and 18 in emys and stages 32-34 in lacerta. lateral-to-medial as well as anterio ... | 1986 | 3950076 |
| influence of picrotoxin on the retinal sensitivity at different levels of background illumination. | the intensity-response function of the b-wave of the erg in the retina of the turtle (emys orbicularis) was investigated at two different background illuminations--0.01 and 10 lx, before and after blockade of the gaba-ergic transmission by 0.4 mmol/l picrotoxin (pt). a shift of the curve to the left along the intensity axis at both backgrounds was observed after pt treatment. the region where the b-wave amplitude was linear function of the logarithm of the stimulus intensity was also considerabl ... | 1987 | 2962211 |
| [sources of the innervation of the carotid reflexogenic zone in representative reptiles]. | the investigation is dedicated to study sources of the carotid reflexogenic zone innervation in 43 tortoises (testudo horsfieldi and emys orbicularis). in 7 tortoises fine preparation of the vessels and nerves of the cervical area after v. p. vorob'ev has been performed. in 13 animals descending branch of the glossopharyngeal nerve has been resected. in 4--the caudal ganglion of this nerve and in 9 tortoises the caudal ganglion of the vagus nerve have been resected. in 10 tortoises adrenergic ne ... | 1988 | 2468327 |
| temperature-dependent gonadal differentiation in the turtle emys orbicularis: concordance between sexual phenotype and serological h-y antigen expression at threshold temperature. | as in many other turtles, the sexual differentiation of gonads in embryos of emys orbicularis is temperature-sensitive, 100% phenotypic males being obtained below 27.5 degrees c and 100% phenotypic females above 29.5 degrees c. the expression of the serologically defined h-y (sd-h-y) antigen at both low and high temperatures has been shown to be different in gonads and in blood : in gonads, it is closely associated with ovarian structure, whereas in blood it is independent of sexual phenotype an ... | 1988 | 3181647 |
| temperature sex-reversal in amphibians and reptiles. | the sexual differentiation of gonads has been shown to be temperature-sensitive in many species of amphibians and reptiles. in two close species of salamanders, pleurodeles poireti and p. waltl, both displaying a zz/zw mechanism of genotypic sex determination (gsd), the rearing of larvae at high temperatures (30 degrees-32 degrees c) produces opposite effects: zz genotypic males of pleurodeles poireti become phenotypic females whereas zw genotypic females of p. waltl become phenotypic males. sex ... | 1990 | 2393628 |
| steroid metabolism in gonads of turtle embryos as a function of the incubation temperature of eggs. | in embryos of many reptiles, the sexual differentiation of gonads is temperature-dependent. in the turtle emys orbicularis, all individuals become phenotypic males at 25 degrees c, whereas 100% phenotypic females are obtained at 30 degrees c. steroid metabolism in embryonic gonads was studied at both temperatures, during and after the thermosensitive period for sexual differentiation. pools of gonads were incubated for various times, with 3 beta-hydroxy-5-pregnen-20-one (pregnenolone), progester ... | 1991 | 1832288 |
| [distribution of gaba-immunoreactive elements in the reptile amygdaloid complex]. | gaba-immunoreactive (gaba-i) elements (neuronal somata and neuropile) are detected in turtle emys orbicularis and lizard ophysaurus spodus in all structures of ventral and dorsal parts of amygdaloid complex (ac) considered as phylogenetic more ancient and younger, respectively by means of the immunohistochemical method. their maximal quantity in the ventral section of ac is found in the lateral region, lesser--in the ventral, central and medial regions. besides in lizards a specialized laminar d ... | 1992 | 1584309 |
| aromatase activity in gonads of turtle embryos as a function of the incubation temperature of eggs. | in embryos of the european pond turtle, sexual differentiation of gonads is temperature-dependent. production of oestrogens appears to play a key role in this phenomenon. gonadal aromatase activity was measured in embryos incubated at 25 degrees c (masculinizing temperature) and at 30 degrees c (feminizing temperature). at the beginning of the thermosensitive period, the aromatase activity was low at both temperatures but was somewhat higher at 30 than at 25 degrees c. afterwards, it remained lo ... | 1992 | 1562561 |
| the embryological development of primary visual centres in the turtle emys orbicularis. | the development of the primary visual centres was studied in a series of embryos of the turtle, emys orbicularis, incubated at 25 degrees c. the differentiation of both visual and nonvisual diencephalic and mesencephalic structures takes place entirely within the 2nd quarter of the period of incubation; this finding appears to be consistent with previous descriptions of the embryology of 2 other chelonian species, lepidochelys and chelydra. two successive waves of migration, each dividing into i ... | 1993 | 8300423 |
| comparative investigation of retinal responses to brief light stimuli: 2-amino-4-phosphonobutyrate studies--ii. turtle retina (emys orbicularis). | 1. electroretinogram (erg) and responses of single ganglion cells to 75 microseconds light flashes, presented on two different backgrounds, were studied. additionally, stimulation with long lasting stimuli (ordinarily 5 sec on-, 15 sec off-) was used. 2. 2-amino-4-phosphonobutyrate (apb) at a concentration of 450 microm on average was used to separate off- from on- channels. it is known, that in other species apb selectively blocks the activity of on- channel only. 3. the existence of apb- sensi ... | 1993 | 8098683 |
| sensitive stages for the effects of temperature on gonadal aromatase activity in embryos of the marine turtle dermochelys coriacea. | many data suggest an involvement of estrogens in gonadal differentiation in reptiles with temperature-dependent sex determination (tsd). however, the site of estrogen synthesis in two species of freshwater turtles is unclear. in emys orbicularis, estrogens were shown to be produced by the gonads, whereas in trachemys scripta, gonadal steroids were not detected. the marine turtle dermochelys coriacea exhibits tsd but in gonadal development, ovarian differentiation is delayed. gonadal aromatase ac ... | 1993 | 8262357 |
| early development of gaba-like immunoreactive cells in the retina of turtle embryos. | gamma aminobutyric acid (gaba) is one of the earliest neuroactive substances appearing in the developing central nervous system. the distribution and the time course of the appearance of gaba-like immunoreactivity in the retina of the turtle emys orbicularis were investigated from embryonic stage 13 to hatching. the first gaba-like immunoreactive cells were observed at stage 14. these cells were located in both the scleral third of the neuroblastic layer and the inner layers of the retina. they ... | 1994 | 7697864 |
| endocrine sex reversal of gonads by the aromatase inhibitor letrozole (cgs 20267) in emys orbicularis, a turtle with temperature-dependent sex determination. | in embryos of emys orbicularis, the sexual differentiation of gonads is influenced by the incubation temperature of eggs. estrogens administered during the thermosensitive period result in the feminization of gonads at 25 degrees (male-producing temperature), whereas an antiestrogen or aromatase inhibitors masculinize the gonads at 30 degrees (female-producing temperature). the nonsteroidal aromatase inhibitor letrozole induces gonads with different degrees of masculinization, from ovary-like to ... | 1995 | 8775058 |
| fine structure of the dorsal lateral geniculate nucleus of the turtle, emys orbicularis: a golgi, combined hrp tracing and gaba immunocytochemical study. | the afferent and efferent cortical projections of the dorsal lateral geniculate nucleus (gld) of adult specimens of the turtle emys orbicularis were investigated after intraocular or intracortical injections of horseradish peroxidase (hrp), and the distribution of gamma aminobutyric acid (gaba) immunoreactivity in the nucleus was carried out by immunocytochemical techniques, both techniques being combined with light and electron microscopy. in addition, some specimens were prepared for double-la ... | 1995 | 7560269 |
| the ovary retains male potential after the thermosensitive period for sex determination in the turtle emys orbicularis. | emys orbicularis is a turtle with temperature-dependent sex determination. the thermosensitive period (tsp) lies between embryonic stages 16 and 22. gonadal differentiation begins during this period involving oestrogens. treatment with oestrogens during tsp results in the differentiation of ovaries at a male-producing temperature (25 degrees c), whereas treatment with an antioestrogen (tamoxifen) or with nonsteroidal aromatase inhibitors results in gonadal masculinization at a female-producing t ... | 1996 | 8765049 |
| ultrastructure of the calcareous layer eggshell of the turtle emys orbicularis (l.). preliminary study. | the calcareous layer of emys orbicularis eggshell was examined by scanning electron microscopy. the layer is composed of well distinguished shell units which consist of needle-like crystallites radiating outwards from the cores. the linear structures of the cores on the inner surface appear to be similar to those in the eggshell of mauremys caspica. on the inner surface of shell units of eggs with dead embryos there are flat, conical depressions. this surface in specimens from unfertilized eggs ... | 1997 | 9646702 |
| sexual differentiation of gonads as a function of temperature in the turtle emys orbicularis: endocrine function, intersexuality and growth. | emys orbicularis is a freshwater turtle with temperature-dependent sex determination. estrogens play a major role in gonadal differentiation; when they are produced at high levels during the thermosensitive period (tsp), ovaries differentiate; when their synthesis is very low, testes differentiate. estrogens are synthesized from androgens through the activity of aromatase. we examine here two aspects of gonadal differentiation, intersexuality and growth, in e. orbicularis. for gonadal intersexua ... | 1998 | 9662827 |
| retinal and cortical afferents to the dorsal lateral geniculate nucleus of the turtle, emys orbicularis: a combined axonal tracing, glutamate, and gaba immunocytochemical electron microscopic study. | the dorsal lateral geniculate nucleus (gld) of the turtle emys orbicularis has been analyzed with axonal tracing methods and immunocytochemical techniques for glutamate (glu) and gamma-aminobutyric acid (gaba), in combination with a quantitative study of the morphologic characteristics, distribution, and synaptology of the retinofugal and corticofugal terminals. ultrastructural observations show that the vast majority of retinal terminals (rtr) have clear, rounded synaptic vesicles and account f ... | 1998 | 9486826 |
| role of urinary and cloacal bladders in chelonian water economy: historical and comparative perspectives. | the parisian comparative anatomist claude perrault, dissecting an indian giant tortoise in 1676, was the first to observe that the urinary bladder is of an extraordinary size in terrestrial tortoises. in 1799, the english comparative physiologist robert townson suggested that the bladder functioned as a water reservoir, as he had shown previously for frogs and toads. however, these observations went unnoticed in subsequent reports on tortoise water economy that were made by travellers and natura ... | 1998 | 9951413 |
| mitochondrial phylogeography of the european pond turtle, emys orbicularis (linnaeus 1758). | the phylogeny and phylogeography of emys orbicularis was inferred from mitochondrial nucleotide sequences of the cytochrome b gene analysed by dna sequencing and rna heteroduplex analysis. within the family emydidae the monotypic genus emys is affiliated with the nearctic taxa emydoidea blandingii and clemmys marmorata. the analysis of 423 individuals of e. orbicularis, originating throughout its distribution range, revealed a remarkable intraspecific differentiation in 20 different haplotypes w ... | 1999 | 10620234 |
| reelin mrna expression during embryonic brain development in the turtle emys orbicularis. | the expression of reelin messenger ribonucleic acid (mrna) was studied during embryonic brain development in the turtle emys orbicularis, by using radioactive in situ hybridization. a high expression was consistently found in the olfactory bulb and in a few neurons in the marginal zone and, to a lesser extent, in the subplate of the dorsal and medial cortical sectors. in the diencephalon, the ventral division of lateral geniculate nuclei and the prospective reticular thalamic nuclei were strongl ... | 1999 | 10502252 |
| pretectal connections in turtles with special reference to the visual thalamic centers: a hodological and gamma-aminobutyric acid-immunohistochemical study. | projections of the pretectal region to forebrain and midbrain structures were examined in two species of turtles (testudo horsfieldi and emys orbicularis) by axonal tracing and immunocytochemical methods. two ascending gamma-aminobutyric acid (gaba)ergic pathways to thalamic visual centers were revealed: a weak projection from the retinorecipient nucleus lentiformis mesencephali to the ipsilateral nucleus geniculatus lateralis pars dorsalis and a considerably stronger projection from the nonreti ... | 2000 | 10980482 |
| amphibian respiration and olfaction and their relationships: from robert townson (1794) to the present. | the present review examines the developments in the elucidation of the mechanisms of amphibian respiration and olfaction. research in these two areas has largely proceeded along independent lines, despite the fact that ventilation of the nasobuccopharyngeal cavity is a basic element in both functions. the english naturalist robert townson demonstrated, in the 1790s, that amphibians, contrary to general belief, ventilated the lungs by a pressure-pump mechanism. frogs and other amphibians respire ... | 2000 | 11034014 |
| sex reversal and aromatase in the european pond turtle: treatment with letrozole after the thermosensitive period for sex determination. | in the european pond turtle (emys orbicularis), gonadal sex differentiation is temperature-dependent. the temperature sensitive period (tsp) of gonadogenesis lies between stages 16 and 22 of embryonic development. previous studies have shown that embryos incubated at 30 degrees c, a temperature yielding 100% phenotypic females, can be sex reversed by treatments with an aromatase inhibitor administered during tsp or even somewhat after tsp (as of stage 22+). the goal of the present study was to d ... | 2001 | 11555856 |
| molecular phylogenetics of emydine turtles: taxonomic revision and the evolution of shell kinesis. | the 10 extant species of emydine turtles represent an array of morphological and ecological forms recognizable and popular among scientists and hobbyists. nevertheless, the phylogenetic affinities of most emydines remain contentious. here, we examine the evolutionary relationships of emydine turtles using 2092 bp of dna encoding the mitochondrial genes cyt b, nd4, and adjacent trnas. these data contain 339 parsimony informative characters that we use to erect hypotheses of relationships for the ... | 2002 | 11884163 |
| evolutionary significance of different neurochemical organisation of the internal and external regions of auditory centres in the reptilian brain: an immunocytochemical and reduced nadph-diaphorase histochemical study in turtles. | an immunocytochemical and histochemical study was undertaken of the torus semicircularis and nucleus reuniens, the mesencephalic and diencephalic auditory centres, in two chelonian species, testudo horsfieldi and emys orbicularis. the nucleus centralis of the torus semicircularis receives few 5-ht-, th-, substance p-, and menkephalin-immunoreactive fibres and terminals, in marked contrast to the external nucleus laminaris of the torus semicircularis, in which 5-ht-, th-, substance p-, and menkep ... | 2002 | 11755904 |
| msx genes are expressed in the carapacial ridge of turtle shell: a study of the european pond turtle, emys orbicularis. | the turtle shell forms by extensive ossification of dermis ventrally and dorsally. the carapacial ridge (cr) controls early dorsal shell formation and is thought to play a similar role in shell growth as the apical ectodermal ridge during limb development. however, the molecular mechanisms underlying carapace development are still unknown. msx genes are involved in the development of limb mesenchyme and of various skeletal structures. in particular, precocious msx expression is recorded in skele ... | 2003 | 12905019 |
| chemical contaminants and their effects in fish and wildlife from the industrial zone of sumgayit, republic of azerbaijan. | sediment from a wetland adjacent to an industrial wastewater treatment plant in sumgayit contained concentrations of total pahs, total pcbs, aldrin, biphenyl, chlordane, ddt, mercury, beta-endosulfan, heptachlor, alpha-hexacyclohexane (alpha-hch), gamma-hch, and several individual pah congeners that were elevated relative to published sediment quality guidelines. chemical analyses of tissues from european pond turtles (emys orbicularis) had increased levels of many of the same chemicals includin ... | 2003 | 14680332 |
| tectothalamic visual projections in turtles: their cells of origin revealed by tracing methods. | in two species of turtle (emys orbicularis and testudo horsfieldi), retrograde and anterograde tracer techniques were used to study projections from the optic tectum to the nucleus rotundus (rot) and to the dorsal lateral geniculate nucleus (gld). the ipsilateral rot received the most massive tectal projections, stemming from numerous neurons located in the stratum griseum centrale (sgc). these neurons varied in size and shape, many of them having a wide zone of dendritic arborization within bot ... | 2003 | 12541323 |
| [dark and light neurons in the cortical plate of the forebrain of the swamp turtle]. | electron microscopic study of the neuronal composition of emys orbicularis cortical zones as compared with the light microscopy data has revealed that the distinctions in the cell cytoplasm ultrastructure with respect to the dendrite branching pattern and the peculiarities of their localization in the cortical plate are suggestive of a possible metabolic heterogeneity and can serve as a foundation of the morpho-functional characteristics of the neurons. a few neuronal types of neurons have been ... | 2003 | 170892 |
| osteology and skeletal development of apalone spinifera (reptilia: testudines: trionychidae). | despite considerable attention that other groups of reptiles have received, few descriptions of the development and sequences of chondrification and ossification of the entire skeleton of turtles exist. herein, the adult skeleton of the spiny softshell turtle, apalone spinifera (testudines: trionychidae), is described; this description forms a basis of comparison for the embryonic skeleton and its ontogenesis. descriptions are made on the basis of cleared and double-stained embryos and dry skele ... | 2003 | 12616574 |
| effect of eye rotation on visual perception in the turtle emys orbicularis. | 2003 | 748817 | |
| [a study of the behavior of turtles (emys orbicularis and clemmys caspica)]. | 2003 | 5737831 | |
| aortic intimal thickenings in tortoises. | the aorta and coronary arteries of two tortoise species, testudo graeca ibera and emys orbicularis are investigated. the elastic aorta of the first species showed minimal focal intimal thickenings while the muscular aorta of the second presented marked diffuse hyperplasia narrowing the caliber of the vessel. the author discusses this striking finding of the aortic structural differences between the two species investigated as well as the significance of such lesions for atherosclerosis developme ... | 2003 | 594625 |
| pretectal and tectal afferents to the dorsal lateral geniculate nucleus of the turtle: an electron microscopic axon tracing and gamma-aminobutyric acid immunocytochemical study. | the pretectal and tectal projections to the dorsal lateral geniculate nucleus (gld) of two species of turtle (emys orbicularis and testudo horsfieldi) were examined under the electron microscope by using axonal tracing techniques (horseradish peroxidase or biotinylated dextran amine) and postembedding gamma-aminobutyric acid (gaba) immunocytochemistry. after injection of tracer into the pretectum, two types of axon terminals were identified as those of pretectogeniculate pathways. both contained ... | 2004 | 15176088 |
| lymphoid aggregates in gonads of embryos, hatchlings, and young of turtles with temperature-dependent sex determination. | cellular infiltrations forming lymphoid-like aggregates were previously observed in gonads of two turtle species exhibiting temperature-dependent sex determination (tsd): at hatching in chelydra serpentina; at and after hatching in emys orbicularis. we show here that such aggregates are also present in gonads of testudo graeca by the end of embryonic development, suggesting that their occurrence is general in turtles. since in c. serpentina, infiltrations were observed mainly in testes exhibitin ... | 2004 | 14743515 |
| [the helminth fauna of emys orbicularis (european pond turtle) (linnaeus, 1758) living in freshwater.] | twelve european pond turtles, emys orbicularis, collected during 1996-2003 in various areas of the bursa region were examined for helminths. during dissection, the following organs were surveyed for parasites: alimentary tract, lungs and urinary bladder. the 4 helminth species found were patagium lazarewi (digenea), serpinema microcephalus, spironoura armenica and spiroxys contortus (nematoda). this study that aimed at determining the helminth fauna of vertebrates in turkey is the first survey o ... | 2005 | 17167746 |