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[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 ...197995835
[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.1977197748
[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 ...1978213913
[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 ...1978216195
immunoglobulin production in the european pond tortoise, emys orbicularis, immunized with serum protein antigens. 19684173673
[pone tortoises (emys orbicularis) as a possible source of leptospira infection]. 19744281241
[some details concerning the structure of the "lamina terminalis" of the cheloniid "emys orbicularis"]. 19675594417
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 ...19826213109
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).19816458362
salmonella in free living terrestrial and aquatic turtles.detection of salmonella in pet turtles has been the focus of extensive research, but its incidence in free living turtles is not well known. the aim of this study was to evaluate the incidence of salmonella in terrestrial and aquatic species of chelonians inhabiting a national park in southwestern spain. individuals of the terrestrial tortoise testudo graeca (n = 16) and the aquatic turtles emys orbicularis (n = 26) and mauremys leprosa (n = 50) were investigated. maximum incidence of salmonella ...200716979850
helminth communities of the exotic introduced turtle, trachemys scripta elegans in southwestern spain: transmission from native turtles.we report the prevalence and diversity of helminth parasites found in native turtles mauremys leprosa and emys orbicularis from three localities in southwestern spain and we describe the helminth communities of exotic turtles trachemys scripta elegans coexisting in the wild with both native turtle species. five nematodes species were identified, of which serpinema microcephalus was the only species common between two localities, although infection parameters were different between them. this is ...200918799176
isolation, purification and de novo sequencing of tbd-1, the first beta-defensin from leukocytes of reptiles.a novel peptide with antimicrobial activity was isolated from leukocytes of the european pond turtle emys orbicularis and purified to homogeneity by preparative gel electrophoresis followed by reversed phase chromatography. it was highly active in vitro against escherichia coli, listeria monocytogenes, methicillin-resistant staphylococcus aureus, and candida albicans. the isolated peptide was sequenced de novo by tandem mass spectrometry using both collision-induced and electron-transfer dissoci ...200919253295
assessing spatial and temporal population dynamics of cryptic species: an example with the european pond turtle.within the current context of biodiversity loss a number of biodiversity indicators have been developed to help measure the state of nature and how it is changing. however, most indicators are derived from bird populations. reptiles and amphibians could be useful ecosystem indicators, but this requires obtaining precise and unbiased population parameters. this is a particularly challenging task for these two groups of species, because individuals are extremely difficult to detect for various rea ...201020597285
gonadogenesis in embryos of two tortoise species, emys orbicularis l. and testudo graeca l., at different temperatures. 20164778513
a reconsideration of the primary visual system of the turtle emys orbicularis.the retinocerebral projections of emys orbicularis were investigated by means of [3h]-proline or hrp, administered by intraocular injection. two newly-hatched, two juvenile and seven adult specimens were examined. the results reveal contralateral retinal projections to fifteen sites: two in the hypothalamus (the nuclei suprachiasmaticus and periventricularis), five in the thalamus (the nuclei ovalis, geniculatus lateralis ventralis, geniculatus laleralis dorsalis, dorsolateralis anterior and ven ...20061479192
aerobic bacterial microbiota isolated from the cloaca of the european pond turtle (emys orbicularis) in poland.we conducted a comparative analysis of the aerobic cloacal bacteria of european pond turtles (emys orbicularis) living in their natural environment and juvenile turtles reared under controlled conditions in a breeding center. we included 130 turtles in the study. the aerobic bacteria isolated from the cloaca of the juvenile turtles were less diverse and more prevalent than the bacteria isolated from free-living adults. we isolated 17 bacterial species from juvenile captive turtles, among which t ...201525380369
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 ...200312616574
morphological and molecular analyses of the spiruroid nematode, falcaustra araxiana massino, 1924 (= spironoura araxiana) from the european pond turtle (emys orbicularis).there is little information on the phylogenetic position and life cycle of family kathlaniidae. falcaustra araxiana is a member of this family which infects the large intestine of the european pond turtle (emys orbicularis). in the present study, morphological data and molecular analyses based on the 18s rdna were performed on different types of f. araxiana originating from the large intestine and gastric nodules in the turtle. morphological data revealed both larvae and adult stages in the gast ...201727032867
endohelminths of european pond turtle emys orbicularis in southwest iran.very little is known about parasitic diseases of european pond turtles (emys orbicularis) in iran. the objective of this study is to examine parasitic fauna of european pond turtles collected from fars province, southwest iran. carcasses of turtles (n = 52) which died during dredging procedure are collected from earthen fishery basins in zarghan region. they have been died earlier during dredging procedure in different farms. three species of helminths in total were found in gastrointestinal tra ...201627065624
free-living turtles are a reservoir for salmonella but not for campylobacter.different studies have reported the prevalence of salmonella in turtles and its role in reptile-associated salmonellosis in humans, but there is a lack of scientific literature related with the epidemiology of campylobacter in turtles. the aim of this study was to evaluate the prevalence of campylobacter and salmonella in free-living native (emys orbicularis, n=83) and exotic (trachemysscripta elegans, n=117) turtles from 11 natural ponds in eastern spain. in addition, different types of samples ...201323951312
demonstrating the value and importance of combining dna barcodes and discriminant morphological characters for polystome taxonomy (platyhelminthes, monogenea).polystomes are monogenean parasites that infest mainly semi aquatic vertebrates, such as amphibians and chelonians. owing to the lack of discriminative morphological characters and because polystomes are considered to be strictly host- and site-specific, host identity is often used as an additional character for parasite identification. recent genetic studies, however, showed that polystomes infecting freshwater turtles in outdoor turtle enclosures and natural environments, were not strictly hos ...201728336417
[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 ...2003170892
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 ...19841021601
blood proteins in turtles (testudo hermanni, emys orbicularis and caretta caretta). 19769229
analysis of cardiac development in the turtle emys orbicularis (testudines: emidydae) using 3-d computer modeling from histological sections.in this article we present a 3-d modeling study of cardiac development in the european pond turtle, emys orbicularis (of the reptilian order testudines). the study is aimed at elucidating the embryonic development of the horizontal septum in the ventricle and underscoring the importance of 3-d reconstructions in studying morphogenesis. turtles possess one common ventricle, partly divided into three cava by a vertical and a horizontal septum, of which the embryonic origins have so far not been de ...201020583255
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 ...200414743515
[helminthofauna of reptiles in the republic of belarus].analysis of original long-term investigation (1980-2006) and literary data on the helminthofauna of reptiles in the republic of belarus is carried out. seven species of reptiles were examined on southern belarus, 32 species of helminthes were found with total infestation 72.7%. it is established that the helminthofauna of reptiles in the republic of belarus includes 33 species (18 trematodes, two cestodes, 12 nematodes, and one acanthocephalan). the largest number of helminth species (26) was re ...201020349629
first reported case of turtle deaths during a toxic microcystis spp. bloom in lake oubeira, algeria.microcystins analysis was conducted in field cyanobacterial bloom samples and dead terrapin tissues from lake oubeira (algeria) with an aim of studying the cause of the mortality of the freshwater terrapin species emys orbicularis and mauremys leprosa during october 2005. the deaths of these two terrapin species were observed during a bloom of microcystis spp. the total microcystin content per phytoplankton biomass evaluated with the methanol extraction-protein phosphatase methodology was 1.12 m ...200818234335
[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 ...200517167746
eimeria species from the european pond turtle, emys orbicularis (reptilia: testudines), in galicia (nw spain), with description of two new species.parasitological examination of feces from 44 emys orbicularis from galicia (nw spain) revealed the presence of 2 new eimerian species, eimeria gallaeciaensis sp. n. and e. emydis sp. n., as well as e. mitraria (laveran and mesnil, 1902) doflein, 1909. oocysts of e. gallaeciaensis n. sp. were found in 20 of 44 (45.4%) turtles and are subspherical to lightly ovoid-ellipsoid, 19.3 x 16.0 (17-22 x 15-18) microm, shape index 1.2 (1.1-1.3), with a smooth, single-layered wall. micropyle and polar granu ...200616629318
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 ...200314680332
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 ...200312541323
measurement of intraocular pressure using tonovet® in european pond turtle (emys orbicularis).twenty-two captive adult european pond turtles (12 males and 10 females) were unrestrained without sedation while intraocular pressure (iop) was measured by means of a tonovet®. mean±sd iop values between 8 and 10 am for all turtles were 5.42±0.96 mm hg (range, 3-9 mm hg). iop between the right and left eye and between males and females was not significantly different. there was no correlation between iop and body weight or body length of animals.201526056909
[turtle isthmic complex of visual nuclei: immunohistochemical study of gamma-aminobutyric acid, choline acetyltransferase, calcium-binding proteins and cytochrome oxidase activity].the distribution of the immunoreactivity for gamma-aminobutyric acid (gaba), choline acetyltransferase (chat), calcium-binding proteins (cabpr) and histochemistry of cytochrome oxidase activity (co) was studied in turtles (testudo horsfieldi, emys orbicularis) isthmal complex of visual nuclei. magnocellular nucleus (imc) was shown to reveal mainly the strongly stained gaba-, parvalbumin (pv)-ir neurons and co-positive cells, as well as variable both in number and degree of intensity of chat-, ca ...201525786321
first reported outbreak of severe spirorchiidiasis in emys orbicularis, probably resulting from a parasite spillover event.the importance of disease-mediated invasions and the role of parasite spillover as a substantial threat to the conservation of global biodiversity are now well known. although competition between invasive sliders trachemys scripta elegans and indigenous european turtles has been extensively studied, the impact of this invasive species on diseases affecting native populations is poorly known. during winter 2012-2013 an unusual event was detected in a population of emys orbicularis (linnaeus, 1758 ...201525667339
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 ...200011034014
presence of the leech placobdella costata in the south of the iberian peninsula.placobdella costata is a leech specific to freshwater turtle emys orbicularis. both genera are native to north america and have co-evolved and undergone dispersion through the palearctic. the leech is present throughout the mediterranean area, always associated with e. orbicularis. their only known presence in the iberian peninsula is in the north and center of the peninsula. here we present the first description of the leech in southern spain (andalusia) in association with a small fragmented p ...201424827095
haemogregarines from western palaearctic freshwater turtles (genera emys, mauremys) are conspecific with haemogregarina stepanowi danilewsky, 1885.the majority of haemogregarina species have been based on the morphology of their erythrocytic stages and supposed strict host specificity. the quantity of species with a limited number of overlapping diagnostic traits has led to a considerable mess in haemogregarine taxonomy and significant synonymy. we analysed host specificity, intra- and interspecific variability, evolutionary relationships, and the distribution of the type species of the genus haemogregarina--h. stepanowi. the morphology of ...201424476992
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 ...19989951413
determination of antimicrobial and heavy metal resistance profiles of some bacteria isolated from aquatic amphibian and reptile species.the aim of the present study was to determine the level of antibiotic resistance patterns and distribution of heavy metal resistance of bacterial isolates from aquatic animals (lissotriton vulgaris, pelophylax ridibundus, emys orbicularis, mauremys rivulata, and natrix natrix) in turkey (kavak delta). a total of 153 bacteria have been successfully isolated from cloaca and oral samples of the aquatic amphibians and reptilians which were found, namely, aeromonas sp. (n = 29), plesiomonas sp. (n =  ...201423959346
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 ...19827128977
[calcium-binding proteins and metabolic activity in thalamotelencephalic parts of the turtle visual system].distribution of three calcium-binding proteins (cabpr) calbindin (cb), calretinin (cr) and parvalbumin (pv) in parallel with metabolic activity (cytochrome oxidase, co) was studied in telencephalic projection zones of the tecto- and thalamofugal visual pathways in experiments on the horsfield's terrapin testudo horsfieldi and the pond turtle emys orbicularis. it was shown that the nucleus rotundus (rot) and dorsal lateral geniculate nucleus (gld) terminal fields in both zones (dorsolateral regio ...201322827028
[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 ...19806967660
[neurochemical characteristics of the turtle optic tectum: comparison with other reptilian species and birds].data on distribution of biologically active substances in the turtle optic tectum are compared with results of similar experiments on other reptilian as well as on avian species. in two turtle species (testudo horsfield and emys orbicularis), immunoreactivity to monoamines (5-ht and th), npy, as well as nadph-d activity were similarly distributed in neuropil of the sgfs retinorecipient part and in that of the sgp/sap periventricular layers. immunoreactivity to neuropeptides sp and m-enk was maxi ...201322567978
[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 ...19806247864
[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 ...1978756699
turtle carapace anomalies: the roles of genetic diversity and environment.phenotypic anomalies are common in wild populations and multiple genetic, biotic and abiotic factors might contribute to their formation. turtles are excellent models for the study of developmental instability because anomalies are easily detected in the form of malformations, additions, or reductions in the number of scutes or scales.201121533278
[use of mouse h-y antiserum for the determination of genetic sex in emys orbicularis l. (testudines, emylidae)]. 1979111857
core-and-belt organisation of the mesencephalic and forebrain auditory centres in turtles: expression of calcium-binding proteins and metabolic activity.the distribution of immunoreactivity to the calcium-binding proteins parvalbumin, calbindin and calretinin and of cytochrome oxidase activity was studied in the mesencephalic (torus semicircularis), thalamic (nucleus reuniens) and telencephalic (ventromedial part of the anterior dorsal ventricular ridge) auditory centres of two chelonian species emys orbicularis and testudo horsfieldi. in the torus semicircularis, the central nucleus (core) showed intense parvalbumin immunoreactivity and high cy ...201020478279
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 ...200415176088
[evolutionary significance of reciprocal connections in the turtle tectofugal visual system].in two turtle species--emys orbicularis and testudo horsfieldi--by the method of anterograde and retrograde traicing method at the light and electron microscopy level, the existence is proven of direct descending projections from the thalamic nucleus of the tectofugal visual system n. rotunds (rot) to the optic tectum. after injection of tracers into rot alone and into rot with involvement of the tectothalamic tract (trtth), occasional labeled fibers with varicosities and terminals are revealed ...201019569560
tectorotundal connections in turtles: an electron microscopic tracing and gaba-immunocytochemical study.the nucleus rotundus of the turtles emys orbicularis and testudo horsfieldi was analysed by axonal tracing methods and post-embedding gaba immunocytochemistry. after injections of horseradish peroxidase or biotinylated dextran amine into the optic tectum, electron microscopic observations showed that the vast majority of ipsilateral tectorotundal axon terminals were small in size, had smooth contours and contained small, round, densely packed synaptic vesicles. these terminals were gaba-immunone ...200717996857
conflicting mitochondrial and nuclear phylogenies for the widely disjunct emys (testudines: emydidae) species complex, and what they tell us about biogeography and hybridization.understanding the mechanisms by which widely disjunct members of a clade came to occupy their current distribution is one of the fundamental challenges of biogeography. here, we used data from 7 nuclear and 1 mitochondrial gene to examine the phylogenetic and biogeographic history of emys, a clade of turtles that is broadly disjunct in western and eastern north america and europe. we found strong disagreement between mitochondrial and nuclear gene trees, with mitochondrial dna supporting the mon ...200920525565
[calcium-binding proteins and cytochrome oxidase activity in the turtle optic tectum characterzing the visual tectofugal pathway].using immunohistochemistry and tracer technique, we studied in the optic tectum of turtles (emys orbicularis and testudo horsfieldi) the distribution of cabpr (parvalbumin, pv, calbindin, cb, calretinin, cr) before and after horseradish peroxidase delivery into nucleus rotundus (rot). in parallel, activity of cytochrome oxidase (co) was studied. in the main link of the tectofugal visual pathway (the central gray layer, sgc) in the both chelonian species rare pv-ir, as well cb- and cr-ir neurons ...201425434193
[calcium-binding proteins and cytochrome oxidase activity in the turtle optic tectum characterzing the visual tectofugal pathway].using immunohistochemistry and tracer technique, we studied in the optic tectum of turtles (emys orbicularis and testudo horsfieldi) the distribution of cabpr (parvalbumin, pv, calbindin, cb, calretinin, cr) before and after horseradish peroxidase delivery into nucleus rotundus (rot). in parallel, activity of cytochrome oxidase (co) was studied. in the main link of the tectofugal visual pathway (the central gray layer, sgc) in the both chelonian species rare pv-ir, as well cb- and cr-ir neurons ...201425507791
[neurons in visual thalamic centers of turtles, projecting upon the telencephalon, express different types of calcium-binding proteins: combined immunohistochemical and tracer study].in turtles (testudo horsfieldi, emys orbicularis) the immunoreactivity for calbindin (cb), parvalbumin (pv), calretinin (cr), and colocalization of pv and cb in neurons of visual thalamic nuclei (rot, gld) projecting to the telencephalon were studied using combined immunohistochemical and tracer method. the predominance of cb-ir neurons in rot, cb-ir and cr-ir neurons in gld and a lower amount of pv-ir neurons in both nuclei were shown. with double labeling fluoroimmunohistochemistry technique t ...201626983281
[effect of hypoxia on amnion rhythmic contractions and heart rate in the embryonic european pond turtle emys orbicularis (reptilia: emydidae)].the effect of acute hypoxia (10% o2 for 30 min) on the rate of amnion rhythmic contractions and heart rate (hr) was studied in two age groups of european pond turtle (emys orbicularis) embryos, on days 19-27 and 37-43 of incubation (30-40 and 60-70% of the period until hatching). under the control conditions, the two age groups of embryos did not differ from each other in either parameter. hypoxia did not affect significantly the amnion contraction rate but decreased the hr. the time course of t ...201618771031
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 ...19957560269
prevalence and intensity of blood apicomplexan infections in reptiles from romania.in order to evaluate prevalence and intensity of apicomplexan hemoparasites in free-ranging reptiles from romania, blood smears were collected from european pond turtles (emys orbicularis), sand lizards (lacerta agilis), and spur-thighed tortoises (testudo graeca). all three host species were positive for blood parasites, with prevalence of infected individuals between 60.71% and 100% and variable intensity. similarities and differences with other epidemiological data are discussed.200818283494
oxygen consumption as related to the development of the extraembryonic membranes and cardiovascular system in the european pond turtle (emys orbicularis) embryogenesis.the rate of oxygen consumption (v(o2)), embryo mass, distribution and mass of the chorioallantoic membrane (cam), heart rate (hr), heart mass, and amnion rhythmic contractions (arc) were studied in eggs of the european pond turtle (emys orbicularis) incubated at 28 degrees c for 62.5+/-0.3 days. the v(o2) rapidly increased beginning from incubation day 19 (d19) to a maximum on d50 and then decreased until pipping. the rapid v(o2) rise was correlated with an increase in the cam surface and mass, ...200717869562
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 ...19852410486
[effect of temperature on the rate of oxygen consumption during the second half of embryonic and early postembryonic development of european pond turtle emys orbicularis (reptilia: emydidae)].oxygen consumption by eggs of european pond turtle was determined at two constant incubation temperatures of 25 and 28 degrees c during the second half of embryogenesis. during development at both temperatures, the rate of oxygen consumption initially increased to remain constant during the last quarter of embryogenesis. the difference between the rates of oxygen consumption at these temperatures decreased during the studied period. the coefficient q10 for the rate of oxygen consumption decrease ...201616240756
chromosomal damage in two species of aquatic turtles (emys orbicularis and mauremys caspica) inhabiting contaminated sites in azerbaijan.the caspian region and specifically the apsheron peninsula of azerbaijan are known to be polluted with a variety of environmental contaminants. these complex mixtures of contaminants make risk assessment difficult. we used the flow cytometry method (fcm) and the micronucleus assay (mn) to assess chromosomal damage in aquatic turtles (emys orbicularis, the european pond turtle; and mauremys caspica, the caspian turtle) inhabiting contaminated wetlands in azerbaijan. evidence of genetic damage was ...200516220359
[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 ...19836661054
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 ...200312905019
[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 ...19836838385
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 ...200211755904
[demonstration of afferent connections of the forebrain in emys orbicularis turtles by the peroxidase method].the transport of horseradish peroxidase (hrp) out of the injection site in the dorsal ventricular ridge was studied in turtles emys orbicularis. labeled cells in the forebrain were observed in the paleostriatum among fibers of the lateral forebrain bundle. in the thalamus most of cells containing the granular hrp reaction product were located in the n. rotundus, n. reuniens and perirotundal nuclei (n. dorso-medialis anterior, n. magnocellularis thalami, n (centralis) lateralis, n. dorso-medialis ...2010654713
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 ...200010980482
dating cryptodiran nodes: origin and diversification of the turtle superfamily testudinoidea.the superfamily testudinoidea is the most diverse and widely distributed clade of extant turtles. surprisingly, despite an extensive fossil record, and increasing amount of molecular data available, the temporal origin of this group is still largely unknown. to address this issue, we used a comprehensive molecular dataset to perform phylogenetic and molecular dating analyses, as well as seven fossil constraints to calibrate the ages of the nodes in the phylogeny. the molecular dataset includes t ...201222100825
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 ...199910502252
comparative genomics identifies epidermal proteins associated with the evolution of the turtle shell.the evolution of reptiles, birds, and mammals was associated with the origin of unique integumentary structures. studies on lizards, chicken, and humans have suggested that the evolution of major structural proteins of the outermost, cornified layers of the epidermis was driven by the diversification of a gene cluster called epidermal differentiation complex (edc). turtles have evolved unique defense mechanisms that depend on mechanically resilient modifications of the epidermis. to investigate ...201626601937
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 ...19938262357
gut microbiota isolated from the european pond turtle (emys orbicularis) and its antimicrobial resistance.the aim of the study was to isolate cultivable gut microbiota from european pond turtles kept at the lithuanian zoo and to determine antimicrobial resistance of the isolates. the study subjects included 8 elderly turtles living at the lithuanian zoo for about 50 years as well as their offspring - 24 young individuals (1-2 years old) that were hatched at the same zoo. animals were not exposed by treatment with antimicrobials during the last 3 years. gut samples were taken from the cloaca and inoc ...201628092603
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 ...19979646702
sex reversal in reptiles: reproductive oddity or powerful driver of evolutionary change?is sex a product of genes, the environment, or both? in this review, we describe the diversity of sex-determining mechanisms in reptiles, with a focus on systems that display gene-environment interactions. we summarise the field and laboratory-based evidence for the occurrence of environmental sex reversal in reptiles and ask whether this is a widespread evolutionary mechanism affecting the evolution of sex chromosomes and speciation in vertebrates. sex determination systems exist across a conti ...201627794577
the good, the bad and the ugly: emys trinacris, placobdella costata and haemogregarina stepanowi in sicily (testudines, annelida and apicomplexa).endemic sicilian pond turtles emys trinacris fritz, fattizzo, guicking, tripepi, pennisi, lenk, joger et wink were examined for the presence of haemogregarine parasites. the presence of haemogregarines, occurring mainly in the microgametocyte stage (13.2 ± 0.12 μm in length and 6.4 ± 0.52 μm in width), was observed in approximately 9% of the sampled e. trinacris. based on the observed morphology and on the sequencing of nuclear 18s rdna, we identified the parasite as haemogregarina stepanowi dan ...201627579559
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 ...19947697864
phylogeny and temporal diversification of the new world pond turtles (emydidae).we present a comprehensive multigene phylogeny and time tree for the turtle family emydidae. our phylogenetic analysis, based on 30 nuclear and four mitochondrial genes (23,330 total base pairs) sequenced for two individuals for each of the currently recognized species of the subfamily emydinae and two species from each of the more species-rich deirochelyinae genera, yielded a well-supported tree that provides an evolutionary framework for this well-studied clade and a basis for a stable taxonom ...201627400630
measurement of tear production using phenol red thread and standardized endodontic absorbent paper points in european pond turtles (emys orbicularis).the objective of this study was to determine the aqueous fraction of the tear film using the phenol red thread test (prtt) and paper point tear test (pptt) in healthy adult european pond turtles (emys orbicularis). twenty-four healthy adult european pond turtles were studied. measurement of tear secretion was performed using the prtt and standardized endodontic absorbent pptt. horizontal palpebral fissure length (hpfl) was measured using digital calipers and was correlated with the weight of the ...201425632669
skin and skeletal system lesions of european pond turtles (emys orbicularis) from natural habitats.water pollution is known to play an important role in the pathogenesis of plastron, carapace and skin diseases of turtles. in this study, a total of 150 european pond turtles (emys orbicularis) of different age and both sexes, originating from natural habitats in serbia, were examined for morphological changes of the skin, plastron, carapace and skeletal system. the turtles were taken out from their natural habitats in lake ludas, lake palic and lake tresetiste. after artificial hibernation, the ...201424334084
dna barcodes reveal the presence of the introduced freshwater leech helobdella europaea in spain.abstract we report the finding of the freshwater leech helobdella europaea in spain for the first time. three leech specimens were found attached to the european pond turtle emys orbicularis. helobdella europaea is not a blood feeder and, like all members of the genus, feeds on the hemolymph of aquatic invertebrates including snails and worms. despite the fact that the original geographical distribution or source population of this species is unknown, the close relationship between h. europaea a ...201423885897
differences in parvalbumin and calbindin chemospecificity in the centers of the turtle ascending auditory pathway revealed by double immunofluorescence labeling.using double immunofluorescence labeling, quantitative ratio between parvalbumin- and calbindin-containing neurons, neurons that co-localize both peptides, as well as the intensity of their immunoreactivities were studied in the brainstem, midbrain and forebrain auditory centers of two chelonian species, testudo horsfieldi and emys orbicularis. in the spiral ganglion and first-order cochlear nuclei, highly immunoreactive parvalbumin-containing neurons predominated, and almost all neurons in thes ...201222820305
nr2c and nr2d subunits of nmda receptors in frog and turtle retina.glutamate nmda (n-methyl-d-aspartate) receptors are widely distributed in the central nervous system where they are involved in cognitive processes, motor control and many other functions. they are also well studied in the retina, which may be regarded as a biological model of the nervous system. however, little is known about nr2c and nr2d subunits of nmda receptors, which have some specific features as compared to other subunits. consequently the aim of the present study was to investigate the ...201222386206
invasive species threat: parasite phylogenetics reveals patterns and processes of host-switching between non-native and native captive freshwater turtles.one of the major threats to biodiversity involves biological invasions with direct consequences on the stability of ecosystems. in this context, the role of parasites is not negligible as it may enhance the success of invaders. the red-eared slider, trachemys scripta elegans, has been globally considered among the worst invasive species. since its introduction through the pet trade, t. s. elegans is now widespread and represents a threat for indigenous species. because t. s. elegans coexists wit ...201121767431
the fish in the turtle: on the functionality of the oropharynx in the common musk turtle sternotherus odoratus (chelonia, kinosternidae) concerning feeding and underwater respiration.in tetrapods, the oropharyngeal cavity and its anatomical structures are mainly, but not exclusively, responsible for the uptake and intraoral transport of food. in this study, we provide structural evidence for a second function of the oropharynx in the north american common musk turtle, sternotherus odoratus, kinosternidae: aquatic gas exchange. using high-speed video, we demonstrate that s. odoratus can grasp food on land by its jaws, but is afterward incapable of lingual based intraoral tran ...201020665819
unexpected early extinction of the european pond turtle (emys orbicularis) in sweden and climatic impact on its holocene range.using ancient dna sequences of subfossil european pond turtles (emys orbicularis) from britain, central and north europe and accelerator mass spectrometry radiocarbon dating for turtle remains from most swedish sites, we provide evidence for a holocene range expansion of the pond turtle from the southeastern balkans into britain, central europe and scandinavia, according to the 'grasshopper pattern' of hewitt. northeastern europe and adjacent asia were colonized from another refuge located furth ...200919222749
heterochrony in limb evolution: developmental mechanisms and natural selection.the tetrapod limb provides several examples of heterochrony-changes in the timing of developmental events. these include species differences in the sequence of skeletal chondrogenesis, in gene transcription in the developing limbs, and in the relative time at which forelimb and hind limb buds develop. here, we examine (i) phylogenetic trends in limb heterochrony; (ii) changes in developmental mechanisms that may lead to heterochrony; and (iii) the possible role that heterochrony plays in generat ...200919130597
characterization of microsatellite loci in the european pond turtle emys orbicularis.a set of eight highly polymorphic microsatellite markers was isolated and characterized from a genomic library enriched for dinucleotide repeats in the european pond turtle, emys orbicularis. the markers were tested for polymorphism in a total of 33 turtles sampled in two natural ponds in the nature reserve of kerkini, northern greece. number of alleles varied from 10 to 18, and expected heterozygosity ranged between 0.738 and 0.921. this novel set of loci will be particularly useful to assess f ...200921564599
the immunohistochemical localization of synaptophysin protein (p38) in the gastro-entero-pancreatic (gep) system of reptiles.the gastro-entero-pancreatic (gep) system of four reptilian species: turtle (emys orbicularis), lizards (lacerta viridis and lacerta agilis) and snake (natrix natrix) has been investigated immunohistochemically for the presence and topographic distribution of synaptophysin. among the studied reptiles, only in turtles were neural, glial and neuroendocrine elements labelled for this marker protein. semi-quantitative evaluation of the immunolabelled neural structures distributed throughout the gast ...200918829074
molecular characterization of the gastrula in the turtle emys orbicularis: an evolutionary perspective on gastrulation.due to the presence of a blastopore as in amphibians, the turtle has been suggested to exemplify a transition form from an amphibian- to an avian-type gastrulation pattern. in order to test this hypothesis and gain insight into the emergence of the unique characteristics of amniotes during gastrulation, we have performed the first molecular characterization of the gastrula in a reptile, the turtle emys orbicularis. the study of brachyury, lim1, otx2 and otx5 expression patterns points to a highl ...200818628985
[extrinsic cells, immunoreactive to ca-binding protein, as sources of thalamic visual centres in tortoises].extrinsic sources of calcium-binding proteins involved in immunoreactive innervation of the visual thalamic nuclei rot and gld in turtles (testudo horsfieldi and emys orbicularis) were studied using hrp tracing method and immunohistochemistry. in 1.5-4.5 months after monocular enucleation calbindin (calb)-, parvalbumin (parv)- and calretinin (calr)-labeling was found in fragments of degenerated retinal fibers in the contralateral optic tract and in some retinorecipient structures (optic tectum, ...200516706155
[growth and oxygen consumption in embryonic and early postembryonic development of european pond turtle emys orbicularis (reptilia: emydidae)].experiments on developing eggs of european pond turtle (emys orbicularis) demonstrated s-shaped changes in the rate of oxygen consumption and body weight during embryonic development. the rate of oxygen consumption and weight progressively increased within 70 days after hatching. during embryogenesis, the rate of oxygen consumption decreased. after hatching, it increased but then decreased to a certain level, which remained constant to the end of the studied period. we observed unidirectional ch ...201616004284
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 ...200211884163
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 ...200111555856
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 ...199910620234
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 ...19989662827
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 ...19989486826
o.h.--a strong slow wave sleep inducing factor in tortoise (emys orbicularis).the paper would be a contribution to the very complex and not yet clarified field of neurochemistry of slow wave sleep (sws). the study was performed on 30 tortoises (emys orbicularis): 20 "donors" and 10 "receivers". the animals were equipped with chronic cannula inserted in the third ventricular space and electrodes for electrographic recording (eeg, eog, emg and ecg). the controls consisted in administration into the third ventricle of receivers of 30 microliters of saline or concentrated cer ...20169653809
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 ...19968765049
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