| some comparative aspects of the organ distribution of superoxide dismutase activity in the freshwater turtle, pseudemys scripta elegans. | 1. superoxide dismutase activities in five tissues of the relatively anaerobic freshwater turtle were compared with sod activities in the same tissues of two mammalian species (mouse and rabbit) with a more usual pattern of dependence on o2 availability. 2. sod activities in brain, lung and skeletal muscle, but not liver or cardiac muscle, are significantly lower in the turtle. the turtle also shows differences in the pattern of relative sod activities in various tissues as compared to the two m ... | 1977 | 318271 |
| mirex residues in eggs and livers of two long-lived reptiles (chrysemys scripta and terrapene carolina) in mississippi, 1970-1977. | | 1979 | 519044 |
| calcitonin-gene related peptide is an evolutionarily conserved marker within the amniote thalamo-telencephalic auditory pathway. | the distribution of neurons and fibers containing calcitonin-gene-related peptide (cgrp) was mapped in the thalamo-telencephalic auditory pathways of four amniote species, rats, pigeons (columba livia), caiman (caiman crocodilus), and turtles (pseudemys scripta). in colchicine-treated turtles and pigeons, numerous cgrp+ perikarya were observed in the auditory relay nucleus of the thalamus (n. reuniens of reptiles, and n. ovoidalis of birds). in pigeons, these neurons were most abundant in the ou ... | 1991 | 1765582 |
| pet turtles: a continuing international threat to public health. | the occurrence of salmonella spp. in red-eared (pseudemys scripta elegans) turtle eggs imported into canada from louisiana in june to september 1988 was examined. of 28 lots tested, six (21%) lots from three of four exporters harbored salmonellae. salmonella poona and salmonella arizonae were frequently encountered in both fertile eggs and packaging moss. turtles hatched in our laboratory from affected lots of eggs shed salmonella in tank water for up to 11 months. widespread use of gentamicin o ... | 1990 | 2372004 |
| relation of plasma thyroxine binding to thyroidal activity and determination of thyroxine binding proteins in a turtle, pseudemys scripta. | the ability of plasma to bind thyroxine (t4) was examined in the turtle, pseudemys scripta, in relation to variations in thyroidal state associated with age, sex, environment, and surgical and chemical manipulations. relative plasma binding activity was assessed by use of binding to [125i]t4 on minicolumns of sephadex g-25 (fine). hypothyroidism induced by surgical thyroidectomy (tx) or goitrogen (methimazole) treatment resulted in a marked depression of plasma binding (50- to 100-fold) in juven ... | 1990 | 2127405 |
| isolation and structural characterization of insulin, glucagon and somatostatin from the turtle, pseudemys scripta. | the chelonians occupy an important position in phylogeny representing a very early branching from the ancestral reptile stock. hormonal polypeptides in an extract of the pancreas of the red-eared turtle were purified to homogeneity by reversed phase hplc and their primary structures were determined. turtle insulin is identical to chicken insulin. turtle glucagon differs from chicken glucagon by the substitution of a serine by a threonine residue at position 16 and from mammalian glucagon by an a ... | 1990 | 1974347 |
| modulation of neuropeptide-stimulated pituitary hormone secretion in hatchling turtles. | neuropeptides that have relatively narrow actions on mammalian pituitary secretion may have divergent effects on pituitary hormone secretion in ectothermal vertebrates. in turtles, secretion of both thyrotropin (tsh) and growth hormone (gh) can be stimulated in vitro by thyrotropin-releasing hormone (trh) and by members of corticotropin-releasing hormone (crh) and growth hormone-releasing hormone (ghrh) peptide families. to determine if these neuropeptides share common modes of action, and to st ... | 1990 | 1967241 |
| isolation, purification and primary structure of insulin from the turtle chrysemys dorbigni. | insulin a and b chains from pancreas of the turtle chrysemys dorbigni have been purified to homogeneity, and their primary structures have been determined. the sequence of the a chain is g-i-v-e-q-c-c-h-n-t-c-s-l-y-q-l-e-n-y-c-n, and that of the b chain is a-a-n-q-h-l-c-g-s-h-l-v-e-a-l-y-l-v-c-g-e-r-g-f-f-y-s-p-k-a. the amino acid sequence of chrysemys insulin is identical to that of another turtle (pseudemys scripta), the chicken, and turkey. when compared with alligator insulin, it has three c ... | 1991 | 1808015 |
| identification of cholecystokinin/gastrin peptides in frog and turtle. evidence that cholecystokinin is phylogenetically older than gastrin. | peptides homologous to mammalian cholecystokinin (cck) and gastrin in brain, antrum, and small intestine of an amphibian (the bullfrog, rana catesbeiana) and a reptile (the turtle, pseudomys scripta) were characterized. all tissues contained peptides reacting with antisera specific for the carboxyamidated c-terminal tetrapeptide common for cck and gastrin. extracts of all tissues, except the turtle antrum, also reacted with an antiserum specific for mammalian sulfated cck, while no extract conta ... | 1992 | 1633800 |
| mechanism of intracardiac shunting in the turtle pseudemys scripta. | two principal hypotheses account for right-left (r-l) intracardiac shunting in reptiles. the "pressure shunting" hypothesis proposes no functional separation between the ventricular cava during systole. the "washout shunting" hypothesis suggests that during systole, the cavum pulmonale (cp) is functionally separate from the rest of the ventricle. the purpose of this study was to test these hypotheses during control, after acetylcholine (ach) administration, after epinephrine (epi) administration ... | 1992 | 1621878 |
| identification and purification of a high-affinity thyroxine binding protein that is distinct from albumin and prealbumin in the blood of a turtle, trachemys scripta. | fractionation of plasma proteins in the turtle, trachemys scripta, confirmed the presence of a high-affinity thyroxine (t4) binding protein (tbp) that was distinct from albumin (alb) and prealbumin (pa). the tbp was isolated by adsorption on a t4-affinity column and a high degree of purification was achieved by gel filtration and preparative electrophoresis. analysis by reversed-phase hplc showed a single peak of protein with t4 binding activity. the electrophoretic mobility of the tbp, based on ... | 1992 | 1601251 |
| measurement of plasma thyroxine binding protein in relation to thyroidal condition in the turtle, trachemys scripta, by radioimmunoassay. | polyclonal (rabbit) antisera were generated against a high-affinity plasma thyroxine (t4) binding protein (tbp) purified from the turtle, trachemys scripta, and used to develop a specific radioimmunoassay (ria). the ria demonstrated the presence of an immunochemically related protein in the plasma of several other species of trachemys and in members of several other genera from the same family, emydidae. plasma from all nonemydids and some emydid genera either showed no competition or nonparalle ... | 1992 | 1563614 |
| cerebral anoxia tolerance in turtles: regulation of intracellular calcium and ph. | to investigate mechanisms of cerebral anoxia tolerance, cerebrocortical intracellular calcium ([ca2+]i) and ph (phi) regulation were compared in turtles (trachemys scripta) and laboratory rats. [ca2+]i and phi in living 200 to 300-microns-thick cortical brain slices were measured with the fluorescent indicators fura-2/acetoxymethyl ester (am) and 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein during exposure to anoxia. within 5 min, [ca2+]i increased to > 1,000 nm in rat brain slices exposed to ... | 1992 | 1481942 |
| diagnostic exercise: high mortality in red-eared slider turtles (pseudemys scripta elegans). | | 1992 | 1479815 |
| binding of the benzodiazepine ligand [3h]-ro 15-1788 to membrane preparations of the rabbit and turtle retina. | 1. we have studied the binding of [3h]-ro 15-1788 to membrane preparations of the retina of rabbit (lepus cunicula) and turtle (pseudemys scripta elegans). 2. in both species, [3h]-ro 15-1788 binding was maximal at 0 degrees c and decreased with increasing temperature. it was saturable, protein concentration-dependent and specific. flunitrazepam, unlabelled ro 15-1788 and ethyl-beta-carboline were the most effective displacers, whereas ro 5,4864 was ineffective. 3. in both turtle and rabbit reti ... | 1992 | 1354109 |
| stimulation of in vitro steroidogenesis by pituitary hormones in a turtle (trachemys scripta) within the temperature-sensitive period for sex determination. | to investigate the possible involvement of pituitary hormones in the regulation of steroidogenesis during reptilian sexual differentiation, we tested the ability of gonadotropin (ovine fsh), adrenocorticotropin (porcine acth), and growth hormone (bovine gh) to stimulate in vitro steroidogenesis in embryonic adrenal-kidney-gonad complexes (akgs) of a turtle, trachemys scripta, during and after the temperature-sensitive period for sex determination (tsp). radioimmunoassays were used to measure pro ... | 1992 | 1337278 |
| choroid plexus, ependyma and arachnoidea express receptors for vitamin d: differences between "seasonal" and "non-seasonal" breeders. | autoradiographic studies with [3h]1,25-dihydroxyvitamin d3 demonstrated nuclear high affinity binding sites (receptors) in epithelial cells of choroid plexus, ependyma and arachnoid in "seasonal" breeders of various vertebrate phyla, namely xiphophorus helleri, hyla crucifer, xenopus laevis, bufo woodhousei, chrysemys scripta, anolis carolinensis, nerodia sipedon and phodopus sungorus, but vitamin d receptors were undetectable in these tissues in non-seasonal breeders, such as zebra finch, labor ... | 1992 | 1329147 |
| two new species of the genus caminacarus (acarina: cloacaridae) from turtles in louisiana. | caminacarus chrysemys sp. n. and caminacarus terrapenae sp. n. are described from the cloaca of chrysemys scripta elegans and terrapene carolina in louisiana. the former species is very similar to caminacarus deirochelys but differs in the form of the dorsal shield which has longer lateral elongations and the median dorsal elongation does not extend to the genital sclerite, structure of the anterodorsal wall of the gnathosomal base which is closed forming a ringlike apodeme, and structure of the ... | 1975 | 1117354 |
| activation of latent salmonella and arizona organisms by dehydration of red-eared turtles, pseudemys scripta-elegans. | salmonella and arizona organisms could not be isolated from water samples, feces, and tissues of turtles prior to the experiment. after stressing, salmonella organisms were isolated from tissues of 7 of 27 stressed turtles and from only 1 of 12 unstressed turtles. arizona organisms were isolated from 9 of 36 stressed turtles whereas results for all 12 unstressed turtles were negative. | 1978 | 637401 |
| metabolism of 14c-histamine in amphibians (bufo bufo) and reptiles (pseudemys scripta and testudo hermanni). | | 1974 | 4205336 |
| potential pathogens in the environment: isolation, enumeration, and identification of seven genera of intestinal bacteria associated with small green pet turtles. | bacteriological analyses were performed on fecal swabs and the aquarium water of 27 individually purchased specimens of the small green pet turtle, pseudemys scripta elegans. representatives of aeromonas, citrobacter, enterobacter, klebsiella, proteus, salmonella, and serratia were isolated. enterobacter, klebsiella, and salmonella were encountered in 20% or more of the specimens, whereas aeromonas was isolated from 63%. klebsiella pneumoniae counts ranged from 10(3) to 10(4) per milliliter of a ... | 1973 | 4572984 |
| effect of dry versus wet bowl environment on pet turtles. | recently hatched, certified salmonella-free, red-eared slider turtles (pseudemys scripta elegans) were obtained from a commercial breeder. half of the turtles were kept in a traditional wet-bowl environment, whereas the other half lived in individual dry-bowl environments, except for 30 minutes each day when they were immersed in water and were fed. both groups were fed commercial turtle food. during the 26 weeks of the study, individual weight and general observations were recorded for each tur ... | 1978 | 629431 |
| a monoclonal antibody marker for the paraboloid region of cone photoreceptors in turtle retina. | monoclonal antibodies that specifically label one or more cell types in retina have been produced; however, only a few antibodies that, in addition, recognize distinct subcellular structures in these cells have been reported. during a search for monoclonal antibodies that bind to specific cell types in the turtle (pseudemys scripta elegans) retina, we obtained an antibody (20 93; an igg) that labels the inner segment of cone photoreceptors. ultrastructural immunocytochemistry using immunogold an ... | 1989 | 2790933 |
| oxygen transfer kinetics of red blood cells of the turtle pseudemys scripta elegans. | the kinetics of o2 uptake into, and release from, the red blood cells (rbc) of the turtle pseudemys scripta elegans were determined with a stopped-flow technique at varied temperature (10-30 degrees c) and ph (7.5-7.9). the results were compared to those obtained for rbc of other vertebrates and related to morphometric and physiological data on gas/blood diffusion in turtle lungs. the o2 transfer conductance of rbc, g, for o2 release into high concentrations of dithionite, considered to represen ... | 1989 | 2717823 |
| evidence that neuromedin u may regulate gut motility in reptiles but not in mammals. | neuromedin u-8 induced a monophasic and concentration-dependent contraction of intact small intestine from the turtle, pseudemys scripta, whereas the peptide had no effect upon the motility of rat and guinea pig gut. the maximum response produced by neuromedin u-8 was 56% of that produced by acetylcholine and 62% of that produced by potassium chloride. the potency and maximum response to neuromedin u-8 were unaffected by tetrodotoxin and atropine. the data suggest that neuromedin u may play a ro ... | 1989 | 2620704 |
| binding of [3h] muscimol to the retina of rabbit and turtle. | 1. we studied the binding of [3h]muscimol to membrane preparations of the retina of rabbit (lepus cuniculus) and turtle (pseudemys scripta elegans). 2. in both species, [3h]muscimol binding was maximal at 0 degrees c and decreased with increasing temperature, it was saturable, protein concentration dependent and specific. muscimol, gaba and bicuculline were the most effective displacers, whereas baclofen and diaminobutyric acid were ineffective. 3. in the turtle retina, scatchard analysis indica ... | 1989 | 2576736 |
| 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 |
| distribution of renal calcitonin binding sites in mammalian and nonmammalian vertebrates. | calcitonin (ct), the hypocalcemic hypophosphatemic hormone, is present in many vertebrate species. the principal target organs for ct are, in mammals, kidney and bone, and in fish, bone and gill. we have investigated the presence of renal calcitonin binding sites in a fish (salmo gairdneri), two amphibians (bufo bufo and rana esculenta), two reptiles (pseudemys scripta and gekko gecko), and two birds (gallus domesticus and cothurnix japonica). we compared their distribution to a mammal, the rat ... | 1989 | 2555248 |
| temperature dependence of in vitro pituitary, testis, and thyroid secretion in a turtle, pseudemys scripta. | in vitro culture was used to examine the direct actions of temperature at the level of pituitary hormone [luteinizing hormone (lh), thyrotropin (tsh), growth hormone (gh), prolactin (prl)] responses to neuropeptides and two related peripheral endocrine responses [thyroid hormone (t4) and testicular androgen secretion] to pituitary hormones (tsh and gonadotropins) in a turtle, pseudemys scripta. all these responses were fully suppressed at very low temperatures (5-6 degrees) and maximal near the ... | 1989 | 2512196 |
| 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 |
| immunocytochemical localization of glycine in the retina of the turtle (pseudemys scripta). | we have localized glycine-like immunoreactivity to provide new anatomical detail about glycinergic neurons in the turtle retina. a rabbit antiserum directed against a glycine/albumin conjugate was used with standard fluorescent and avidin-biotin labeling techniques. some processes in the outer plexiform layer and many processes in the inner plexiform layer, numerous somata in the inner nuclear layer, and isolated somata in the ganglion cell layer were immunoreactive. the vast majority of labeled ... | 1989 | 2487656 |
| histochemical classification of neck and limb muscle fibers in a turtle, pseudemys scripta: a study using microphotometry and cluster analysis techniques. | we have attempted to develop an objective, semiquantitative classification of fiber types in turtle neck and limb muscle using microphotometry and multivariate statistical techniques. we first stained serial sections for myosin adenosine triphosphatase (atpase) (with acid and alkaline preincubation and without preincubation), nadh-diaphorase, and two glycolysis-associated markers, alpha-glycerophosphate dehydrogenase (alpha-gpdh) and glycogen phosphorylase a (gpa). this allowed us to characteriz ... | 1989 | 2468778 |
| salmonella colonization in commercial pet turtles (pseudemys scripta elegans). | an epidemiological survey was conducted on two commercial turtle farms in southern louisiana to determine the reason for an apparent increase in the prevalence of salmonella spp. in turtle hatchlings at the time of pre-export certification examination. pond water was consistently found to be contaminated (6/36 samples) with either salmonella newport, s. arizonae, or s. poona. environmental specimens obtained from eggs and turtle hatcheries (204 specimens) failed to yield salmonella spp. a sample ... | 1990 | 2209735 |
| prolonged diving and recovery in the freshwater turtle, pseudemys scripta--iv. effects of profound acidosis on o2 consumption in turtle vs rat (mammalian) brain and heart slices. | the oxygen consumption of rat versus turtle brain and heart slices was compared as a function of extracellular ph and temperature. at ph = 6.20 rat (mammalian) brain and heart slices show a significant depression of oxygen consumption as compared to ph = 7.50 at temperatures of both 24 degrees and 37 degrees c. in the turtle oxygen consumption in brain and heart slices was not depressed at ph = 6.20 compared to ph = 7.50 at 24 degrees c and brain oxygen consumption was not significantly differen ... | 1985 | 2863049 |
| the effects of cold acclimation on electrocardiogram parameters in five species of turtles. | the effects of thermal acclimation at 25 or 5 degrees c on electrical activity in the heart were investigated in pseudemys scripta, terrapene carolina, chrysemys picta marginata, chrysemys picta dorsalis, chelydra serpentina, and sternotherus odoratus. the durations of the qrs complex and p-r, r-t and r-r intervals were found to increase with decreasing body temperature in all animals tested. the amplitudes of the p and t waves and qrs complex were dependent upon both acclimation temperature and ... | 1987 | 2886260 |
| light and electron microscopy of s-antigen- and opsin-immunoreactive photoreceptors in the retina of turtle, chicken, and hedgehog. | s-antigen and opsin-immunoreactive sites were studied in the retina of turtle (pseudemys scripta elegans), chicken (gallus domesticus), and hedgehog, (erinaceus roumanicus) by light-microscopic avidin-biotin-peroxidase and electron-microscopic protein a-gold and immunoglobulin-gold (immunogold) techniques. in general, s-antigen and opsin immunoreactions were exclusively localized to certain photoreceptors of the retinae studied. in turtle and chicken, strong s-antigen immunoreactivity was found ... | 1986 | 2937651 |
| measurement of plasma renin activity in the freshwater turtle. | components of the renin angiotensin system have been identified in many nonmammalian vertebrates. however, in many of these animals, including reptiles, the physiological functions and importance of the system remain unclear. to aid in the study of the system in a reptile we modified a commercially available radioimmunoassay (ria) kit containing antibody against human angiotensin i (ang i) for use in the freshwater turtle, pseudemys scripta. cross-reactivity between anti-human ang i antibodies ( ... | 1988 | 3047000 |
| a monoclonal antibody that binds to photoreceptors in the turtle retina. | we have raised monoclonal antibodies to photoreceptor cells in the retina of the turtle (pseudemys scripta elegans). one of these antibodies, 15-18 (an igg1), was studied by immunoelectron microscopy using colloidal gold, and found to bind to the outer segments of all rods and some single cones, but did not stain turtle double cones. immunoblotting and immunoprecipitation show that antibody 15-18 binds to an antigen of apparent mr approximately 34,5000 which is probably turtle opsin. antibody 15 ... | 1988 | 3067443 |
| gonadotropin-releasing hormone from brains of reptiles: turtles (pseudemys scripta) and snakes (thamnophis sirtalis parietalis). | gonadotropin-releasing hormone (gnrh)-like peptides were present in whole brain extracts of turtle (pseudemys scripta) and snake (thamnophis sirtalis parietalis) with higher content and concentration in the turtle brain. the peptides were identified by cross-reactivity profiles with four gnrh antisera and by retention times on reverse-phase high-pressure liquid chromatography (hplc) compared with synthetic gnrh standards. turtle brain extracts contained two hplc peaks that cross-reacted with gnr ... | 1988 | 3282979 |
| hydroxylation and oxidation of nalidixic acid in the turtle pseudemys scripta elegans. | the turtle pseudemys scripta elegans hydroxylates nalidixic acid into 7-hydroxynalidixic acid; this latter metabolite is oxidised into 7-carboxynalidixic acid. the elimination half-life of nalidixic acid in the turtle is 30 h. no glucuronides of nalidixic- and 7-hydroxynalidixic acid are formed, as they are in man. | 1988 | 3376413 |
| acetylation, deacetylation and hydroxylation of sulphamethoxazole and n4-acetylsulphamethoxazole in the turtle pseudemys scripta elegans. | the turtle pseudemys scripta elegans is able to hydroxylate and acetylate sulphamethoxazole in a way that is comparable to man, i.e. the rate and yield of hydroxylation equals that of the acetylation. the hydroxy metabolites 5-hydroxy- and n4-acetyl-5-hydroxysulphamethoxazole are not glucuronidated. n4-acetylsulphamethoxazole is neither deacetylated nor hydroxylated. | 1987 | 3424645 |
| characterization of renal prolactin-binding sites of two amphibians (ambystoma tigrinum and rana catesbeiana) and a reptile (pseudemys scripta elegans). | the specific binding of 125i-ovine prolactin (oprl) to renal membrane preparations from pseudemys scripta elegans, ambystoma tigrinum, and rana catesbeiana was characterized. all three membranes showed specific oprl binding that was dependent upon time, temperature, ph, and membrane concentration. scatchard analysis of the binding of 125i-oprl revealed high-affinity sites with ka values of 2.1 x 10(10), 3.6 x 10(10), and 1.25 x 10(10) m-1 for kidney membranes of pseudemys, ambystoma, and rana, r ... | 1987 | 3495632 |
| localization of a salmon calcitonin-like molecule in one type of ultimobranchial cells in the freshwater turtle pseudemys scripta. | immunohistochemical methods using affinity adsorbed antibodies raised against the three families of calcitonins (ct) were applied to ultimobranchial (ub) cells in situ to investigate the nature of the chelonian calcitonin molecule and its distribution in the ultimobranchial bodies of the freshwater turtle, pseudemys scripta. in this species, the ub glands were present on both sides and consisted of scattered cell clumps between epithelial vesicular structures. the neighboring parathyroid tissue ... | 1987 | 3549440 |
| observations on the structure of two human 7sk pseudogenes and on homologous transcripts in vertebrate species. | a comparison of the sequence of two human 7sk rna pseudogenes, covering approx. 190 and 240 base-pairs of the structural gene, is presented. both repeated elements are flanked by direct repeats and begin at the 5' end of the gene. each terminates approx. 90 base-pairs short of the 3' end, the latter representing a continuous sequence and the former carrying an internal deletion of about 40 base-pairs, this region being flanked in the progenitor gene by short repeated sequences. southern blotting ... | 1987 | 3663152 |
| postsynaptic potentials of bulbar respiratory neurons of the turtle. | membrane potentials of bulbar respiratory neurons of pseudemys scripta were recorded from unanesthetized, decerebrate animals. efferent neurograms were recorded from the serratus magnus (inspiratory) and pectoralis (expiratory) nerves. the animals were paralyzed and ventilated by a servo-respirator driven by the pectoralis neurogram to mimic the spontaneous turtle respiratory cycle. neurons, comparable to mammalian medullary respiratory neurons, were observed, namely: augmenting inspiratory, aug ... | 1986 | 3704386 |
| renin release in turtles: effects of volume depletion and furosemide administration. | to gain insight into the phylogenetic history of mechanisms controlling renin release, we conducted studies in the freshwater turtle pseudemys scripta. maneuvers known to stimulate renin release in mammals were evoked in the turtle, and the response was compared with that in mammals. cumulative hemorrhage (30% blood vol) in anesthetized turtles failed to increase renin even though arterial pressure was reduced to 50% of control. an even more severe hemorrhage (60% blood loss) or hypotension indu ... | 1985 | 3893163 |
| steroid biosynthesis in turtle testes. | testicular metabolism of radiolabelled substrates (pregnenolone, progesterone and androstenedione) was examined in two species of turtles, pseudemys scripta and sternotherus odoratus. chemical methods (chromatography, derivative formation and crystallization) identified testosterone (in both species) and 5 alpha-androstane-3 beta,17 beta-diol (in s. odoratus) as products. tentative identifications were also made of 20 beta-hydroxypregn-4-en-3-one in both turtles. chromatographic profiles indicat ... | 1985 | 3928242 |
| organization of on-off cells in the retina of the turtle. | 1. the organization of central and peripheral responses for one type of spike-producing cell in the retina of the turtle (pseudemys scripta elegans) has been studied. these cells produced a short burst of spikes following the onset and offset of a small spot of illumination (i.e. on-off cells). the effect of increasing the area of illumination was to include a peripheral inhibition. intracellular on and off responses were, however, affected differently.2. on-off cells marked intracellularly with ... | 1973 | 4702424 |
| mechanical basis for lung volume variability in the turtle pseudemys scripta elegans. | | 1971 | 5545687 |
| effects of synthetic mammalian thyrotrophin releasing hormone, somatostatin and dopamine on the secretion of prolactin and growth hormone from amphibian and reptilian pituitary glands incubated in vitro. | pituitary glands of grassfrog (rana pipiens), bullfrog (rana catesbeiana), clawed toad (xenopus laevis) and two species of terrapin (chrysemys picta and pseudemys scripta) were incubated in medium containing hypothalamic extract (he), thyrotrophin releasing hormone (trh), somatostatin, dopamine, or combinations of these treatments. prolactin and gh concentrations in the medium were determined by densitometry after polyacrylamide-gel electrophoretic separation. hypothalamic extract stimulated sec ... | 1984 | 6146654 |
| the organization of motoneurons in the turtle lumbar spinal cord. | the distribution of motoneurons in the lumbosacral spinal cord of the turtle pseudemys scripta elegans was studied by using the technique of retrograde transport of horseradish peroxidase. a total of 19 different hindlimb muscles were injected with varying amounts of horseradish peroxidase. the resulting distribution of labeled motoneurons was studied in both longitudinal and transverse sections of spinal cord. motoneurons innervating a particular hindlimb muscle are clustered in longitudinally ... | 1984 | 6207212 |
| characterization of the renin-angiotensin system in the turtle pseudemys scripta. | studies were conducted in freshwater turtles pseudemys scripta to define some characteristics of the renin-angiotensin system in this reptile. dialyzed acid-treated kidney extract (1 g tissue per ml water) produced a prolonged pressor response in unanesthetized turtles, which was eliminated by boiling the extract or by pretreating the turtle with [sar1, ile8]angiotensin ii. a rat pressor assay was employed because turtle angiotensin (ang) was bound poorly by the anti-[asp1, ile5, his9]ang i used ... | 1984 | 6377928 |
| studies on the specificity of thyroid response to pituitary glycoprotein hormones. | thyrotropins (tsh) and gonadotropins (luteinizing hormone, lh, and follicle-stimulating hormone, fsh) purified from ovine, bovine, ostrich, sea turtle, and bullfrog pituitary glands were tested for their ability to simulate the thyroid glands of four species of amphibians (three anurans and a urodele), a reptile (the slider turtle), and a bird (the cockerel). all animals tested responded specifically to mammalian, sea turtle, and ostrich thyrotropins; any thyroid-stimulating activity of the gona ... | 1984 | 6436141 |
| morphology of lumbar motoneurons innervating hindlimb muscles in the turtle pseudemys scripta elegans: an intracellular horseradish peroxidase study. | motoneurons in the turtle lumbar spinal cord, electrophysiologically identified as innervating a muscle belonging to a functional group, were injected with horseradish peroxidase by electrophoresis. a total of 45 motoneurons were reconstructed from transverse sections. eleven motoneurons were identified as innervating knee extensor muscles, eight as innervating hip retractor and knee flexor muscles, 14 as supplying ankle and/or toe extensors, and 12 as innervating ankle and/or toe flexor muscles ... | 1984 | 6520242 |
| chemical structure of angiotensin in the turtle, pseudemys scripta. | the chemical structure of angiotensin generated by incubating kidney extract with homologous plasma from the turtle, pseudemys scripta, has been analyzed. the turtle angiotensin was proposed to be [asp1, val5, his9] ang i by its amino acid composition and by its fluorescent peptide mapping. it was the same structure as angiotensin i in the ox and the sheep. the n-terminal amino acid of the turtle angiotensin was not blocked, unlike that of another reptilian angiotensin found in the snake, elaphe ... | 1984 | 6714649 |
| antigen trapping in the spleen of the turtle, chrysemys scripta elegans. | using horse-radish peroxidase (hrp)-anti-hrp immune complexes, 'antigen trapping' was studied in the spleen of the turtle, chrysemys scripta elegans. it was found that antigen-trapping cells were situated in the periellipsoidal lymphocyte sheath of the white pulp only. the antigen-trapping cells have a dendritic character and a large lobulated nucleus. carbon injections revealed that these cells do not phagocytose. the results are discussed with respect to the phylogeny of antigen-trapping cells ... | 1983 | 6840808 |
| the dark brown integumentary pigment of a barnacle (balanus eburneus). a comparative study. | a histochemical analysis involving tinctorial and solubility tests was pursued in conjunction with electron microscopy for the purpose of identifying the dark brown epidermal pigment of a barnacle (balanus eburneus) as melanin and/or ommochrome. histochemically, comparisons were made with other brown pigments located in the subcarapal epidermis of another crustacean, the fiddler crab (uca pugilator), the dorsal skin of the red-backed salamander (plethodon cinereus), the liver and testis of a sli ... | 1983 | 6874419 |
| oxygen equilibria of ectotherm blood containing multiple hemoglobins. | complete isocapnic o2 equilibrium curves (o2ec's) and related blood-gas properties are reported for whole blood of the bullfrog (rana catesbeiana) and the aquatic turtle (pseudemys scripta) at temperatures ranging from 5 to 35 degrees c. p50's for bullfrog and turtle blood at physiological ph and 25 degrees c were 36.6 torr (ph 7.83) and 19.3 torr (ph 7.55), respectively. elevation of blood temperature significantly reduced hemoglobin oxygen affinity in both species (delta h = -8.1 and -7.8 kcal ... | 1980 | 6971463 |
| identification and distribution of neurons presumed to give rise to cerebellar climbing fibers in turtle. a retrograde axonal flow study using radioactive d-aspartate as a marker. | radioactive d-aspartate and horseradish peroxidase were injected into the cerebellar cortex in turtle, pseudemys scripta elegans. while neurons retrogradely labeled with horseradish peroxidase were found in various regions of the spinal cord and brainstem, labeled cells following aspartate injections were only observed in circumscribed regions of the caudal medulla. in rat it was recently reported that climbing fibers, but no other cerebellar afferents, were retrogradely labeled with d-aspartate ... | 1982 | 7172016 |
| evidence for auditory localization ability in the turtle. | evidence is presented that the semiaquatic turtle chrysemys scripta and the terrestrial turtle terrapene carolina major can detect the direction of a tone within their sensitive area of hearing. it is further suggested that not only can these species respond behaviorally to sound without extensive manipulation but can use limited hearing in a problem-solving situation of maze learning. adult emydid turtles (5 c. scripta, 3 t. carolina) learned a y-maze with a 500-c/s signal to an invisible open ... | 1981 | 7186502 |
| electron microscope study of vertebrate liver innervation. | liver fine structure was studied in various groups of vertebrates to reveal intrahepatic nerves. nerve fibers were found in the connective tissue of the liver in all mammals, birds, and reptiles studied (japanese monkey, crab-eating monkey, rabbit, guinea pig, rat, golden hamster, pigeon, japanese quail, and turtle, pseudemys scripta). nerve fibers also made direct contact with hepatocytes in these animals except for the rat and the golden hamster. intrahepatic nerves were rare or absent in amph ... | 1981 | 7316686 |
| acclimation, temperature selection, and heat exchange in the turtle, chrysemys scripta. | turtles acclimated to temperatures between 3 and 19 degrees c were placed in a thermal gradient. the animals usually selected temperatures above 28 degrees c within 1 h after placement in the gradient, attaining a final thermal preferendum between 31 and 33 degrees c. turtles placed in the gradient for extended periods of time were more active during the day; the temperature selected was not related to activity or time of day. turtles were transferred from a constant temperature bath at 10 or 30 ... | 1980 | 7377383 |
| comparison of the pineal complex, retina and cerebrospinal fluid contacting neurons by immunocytochemical antirhodopsin reaction. | the presence of rhodopsin was investigated by an indirect immunocytochemical method in the pineal complex of various vertebrates (carassius auratus, cyprinus carpio, hypophthalamichthys molitrix, lucioperca lucioperca, triturus vulgaris, bombina bombina, rana esculenta, pseudemys scripta elegans, lacerta agilis et viridis, white leghorn chickens, rat), in the retina of lebistes reticulatus, lucioperca lucioperca, rana esculenta, lacerta agilis, pseudemys scripta elegans, the chicken and the rat, ... | 1980 | 7456628 |
| distribution of glial fibrillary acidic protein-immunopositive structures in the brain of the red-eared freshwater turtle (pseudemys scripta elegans). | the distribution of glial fibrillary acidic protein (gfap)-immunoreactivity is described in serial vibratome sections of the turtle brain. the results are discussed in relation to our previous studies of rat and chicken brains. in the turtle brain, the distribution of gfap-positive elements is rather evenly abundant as compared to that observed in the chicken and rat. the gfap-positive structures are fibers of different length and orientation, but the stellate cells are not gfap-positive. the ba ... | 1994 | 7522421 |
| expression of alpha sm actin in terrestrial ectothermic vertebrates. | alpha-smooth muscle (alpha sm) actin of endothermic vertebrates is selectively recognized by the monoclonal antibody anti-alpha sm-1. immunoreactivity to this antibody has been shown to be localized in the nh2-terminal sequence ac-eeed (chaponnier et al. 1994). among terrestrial ectothermic vertebrates, two amphibian (triturus vulgaris, rana esculenta) and three reptilian species (pseudemys scripta elegans, natrix natrix, podarcis sicula) were screened to investigate if their vascular and viscer ... | 1995 | 7553770 |
| vitellogenin induction by xenobiotic estrogens in the red-eared turtle and african clawed frog. | many environmental pollutants have estrogenic activity in animals. xenobiotic estrogens include many pesticides and industrial chemicals that biocumulate. the impact of these common pollutants on the reproductive success of wildlife may be considerable, particularly in threatened or endangered species. this research examined the use of plasma vitellogenin in males as a biomarker for estrogenic xenobiotics in reptiles and amphibians. adult male turtles (trachemys scripta) and frogs (xenopus laevi ... | 1995 | 7556019 |
| fiber-type composition of hindlimb muscles in the turtle, pseudemys (trachemys) scripta elegans. | a description is provided of the fiber-type composition of several hindlimb muscles of the adult turtle, pseudemys (trachemys) scripta elegans. in addition, cross-section areas of each fiber type and an estimation of the relative (weighted) cross-section area (wcsa) occupied by the different fiber types are also provided. seven muscles were selected for study, based on their suitability for future neurophysiological analysis as components of the segmental motor system, and on their homologies wi ... | 1995 | 7666437 |
| a commentary on the segmental motor system of the turtle: implications for the study of its cellular mechanisms and interactions. | a commentary is provided on the segmental motor system of the turtle pseudemys (trachemys) scripta elegans with an emphasis on neuronal, neuromuscular, and muscular mechanisms that control the development of force under normal, fatiguing, and pathophysiological conditions. for the central neuronal component of the segmental motor system, it has recently been shown that intracellular analysis of the firing properties of motoneurons and interneurons can be undertaken for relatively long periods of ... | 1995 | 7666438 |
| a new plasma kinin in the turtle, pseudemys scripta elegans. | | 1970 | 5485284 |
| identification of cholecystokinin from frog and turtle. divergence of cholecystokinin and gastrin occurred before the evolution of amphibia. | cholecystokinins from brain and small intestine of the bullfrog (rana catesbeiana) and red-eared slider turtle (pseudomys scripta) were isolated. the purifications were monitored by an antiserum specific for the common c-terminus of mammalian cholecystokinin and gastrin. the peptide structures were identified by sequence analysis of the intact peptides and proteolytic fragments, mass spectrometry, and amino acid analysis. brain and small intestine of both species contained cholecystokinin-8 and ... | 1994 | 7925386 |
| the relation of the dual thyroxine/vitamin d-binding protein (tbp/dbp) of emydid turtles to vitamin d-binding proteins of other vertebrates. | the relation of a dual binding protein, involved in the transport of both thyroxine (t4) and vitamin d3, in the blood of emydid turtles to blood proteins in other vertebrates was examined immunologically. binding studies with 25-oh-[3h]cholecalciferol (d3) confirmed the presence of a d3-binding protein (dbp) in the plasma of a wide variety of chelonian species representing both major suborders, as well as other species of reptiles, amphibians, birds, and mammals. analysis by polyacrylamide gel e ... | 1994 | 7926631 |
| occurrence and localization of calbindin-d28k in kidney and cerebellum of the slider turtle, trachemys scripta. | since its initial discovery in the avian intestine, calbindin-d28k has been reported to occur in various species and tissues. although calbindin-d28k binds calcium ions in the physiologically relevant range of intracellular calcium, its functional role in the various cell types where it has been localized remains unknown. | 1994 | 8059980 |
| thyroxine-binding protein represents the major vitamin d-binding protein in the plasma of the turtle, trachemys scripta. | structural homology between the high-affinity thyroxine (t4)-binding protein (tbp) in the plasma of the turtle, trachemys scripta, and vitamin d-binding proteins (dbp) of mammals prompted an investigation of plasma vitamin d binding in the turtle. several lines of evidence indicate that the tbp represents the primary binding protein for 25-oh-cholecalciferol (d3) in the turtle plasma. d3-binding protein in whole plasma migrates in the same position as tbp by size-exclusion chromatography and pol ... | 1994 | 8138122 |
| in vivo gnrh responsiveness of lh secretion in the female turtle, trachemys scripta, in relation to the reproductive stage. | the effects of several forms of gonadotropin-releasing hormone (gnrh) on the in vivo secretion of luteinizing hormone (lh) were investigated in the female turtle trachemys scripta. serial injections of large vitellogenic turtles with 1-2 micrograms (ca. 0.15 micrograms/100 g turtle) of chicken gnrh-i (cgnrh-i) and multiple blood sampling revealed that mature females were unresponsive to gnrh. in contrast, both forms of avian gnrh, cgnrh-i and cgnrh-ii, and an avian gnrh analogue (gnrha) signific ... | 1993 | 8224759 |
| species and tissue distribution of the regulatory protein of glucokinase. | rat liver is known to contain a regulatory protein that inhibits glucokinase (hexokinase iv or d) competitively versus glucose. this inhibition is greatly reinforced by the presence of fructose 6-phosphate and antagonized by fructose 1-phosphate and by kcl. this protein was now measured in various rat tissues and in the livers of various species by the inhibition it exerts on rat liver glucokinase. rat, mouse, rabbit, guinea-pig and pig liver, all of which contain glucokinase, also contained bet ... | 1993 | 8373368 |
| ectoplasmic ("junctional") specializations in sertoli cells of the rooster and turtle: evolutionary implications. | ectoplasmic specializations are complex actin-containing structures found at certain sites of intercellular attachment in sertoli cells. current evidence indicates that these structures are a form of actin-associated adhesion junction. in the turtle (pseudemys scripta) and rooster (gallus domesticus) ectoplasmic specializations are known to occur adjacent to sites of attachment to elongate spermatids and are characterized by a layer of "loosely" cross-linked actin filaments that lies next to the ... | 1993 | 8417627 |
| comparative studies of thyroxine binding proteins in turtle plasma using column chromatography. | thyroxine (t4) binding proteins in turtle plasma were compared with those of various mammalian and nonmammalian (fish, birds) species using gel filtration chromatography (bio-gel). high-affinity t4 binding was observed in all mammals studied, in the chicken, and in one species of turtle, trachemys scripta. this high affinity t4 binding protein (tbp) appears to be the major component of t4 transport in the turtle; selective removal of this tbp greatly diminished binding activity in t. scripta pla ... | 1993 | 8428644 |
| gnrh-induced desensitization of in vitro luteinizing hormone secretion in the turtle, trachemys scripta. | gonadotropin-releasing hormone (gnrh)-induced desensitization of pituitary luteinizing hormone (lh) secretion in female turtles (trachemys scripta) was investigated by in vitro superfusion of whole or hemipituitaries with the endogenous forms of the peptide. in sub-adults, lh secretion was rapidly attenuated (desensitized) by both prolonged and pulsatile treatments of chicken ii gnrh (cii-gnrh), but pulsatile gnrh administration was more effective than prolonged administration in stimulating lh ... | 1993 | 8454169 |
| pseudoknots in prion protein mrnas confirmed by comparative sequence analysis and pattern searching. | the human prion gene contains five copies of a 24 nt repeat that is highly conserved among species. an analysis of folding free energies of the human prion mrna, in particular in the repeat region, suggested biased codon selection and the presence of rna patterns. in particular, pseudoknots, similar to the one predicted by wills in the human prion mrna, were identified in the repeat region of all available prion mrnas available in genbank, but not those of birds and the red slider turtle. an ali ... | 2001 | 11160898 |
| differential distribution of chicken-i and chicken-ii gnrh in the turtle brain. | chicken-i and chicken-ii gonadotropin-releasing hormone (ci-gnrh and cii-gnrh) were shown to be differentially distributed in the brain of a turtle, trachemys scripta, by hplc and specific radioimmunoassays. the ci-gnrh was most concentrated in the median eminence (me), while cii-gnrh was most concentrated in the caudal brain regions, especially medulla and cerebellum. the ratio of ci- to cii-gnrh in the me of adults was 8:1. age- and sex-related differences in gnrh concentrations were observed ... | 1993 | 8483800 |
| binding affinities of thyroxine-binding proteins in turtle plasma. | binding affinities (ka) for thyroxine (t4) by blood plasma and purified plasma proteins from two turtles, the slider (trachemys scripta) and snapper (chelydra serpentina), were compared with those of a human using equilibrium dialysis. the purified t4 binding protein (tbp) from t. scripta had a high affinity that was lower by about fivefold than that of human tbg (3.2 x 10(9) vs 1.7 x 10(10) m-1). the affinity of t4 binding by tbp was similar to that determined for whole plasma from this species ... | 1993 | 8504925 |
| motor pool organization of the external gastrocnemius muscle in the turtle, pseudemys (trachemys) scripta elegans. | the spinal cord of the adult turtle, pseudemys (trachemys) scripta elegans, is now considered a promising model for the study of the segmental motor system in the generalized tetrapod. to facilitate such studies we have examined the location, soma geometry, soma size, and number of motoneurons innervating the external gastrocnemius (eg) muscle in this species, as this muscle is ideally suited to the study of interrelations between the neuronal and muscular components of the segmental motor syste ... | 1996 | 8568906 |
| the influence of center-surround antagonism on light adaptation in cones in the retina of the turtle. | the influence of center-surround antagonism on light adaptation in cone photoreceptors was investigated by intracellular recording from red-sensitive cones in the retina of the turtle, pseudemys scripta elegans. test flashes of 0.15-mm diameter were applied at the center of background fields of 0.25-mm or 2.2-mm diameter. immediately upon expanding the background from 0.25 to 2.2 mm, the membrane potential depolarized by about 1-4 mv. the test flash response was enhanced if the depolarization wa ... | 1995 | 8924411 |
| purification and characterization of plasma vitamin d binding protein from the snapping turtle, chelydra serpentina. | vitamin d binding protein (dbp) was isolated from the plasma of the snapping turtle, chelydra serpentina (mixed sex adult), and compared with the previously characterized dual function binding plasma protein that binds both thyroxine (t4) and vitamin d (tstdbp) in an emydid turtle, trachemys scripta. purification of chelydra serpentina dbp (csdbp) was accomplished by ion exchange chromatography, preparative polyacrylamide gel electrophoresis, and reverse-phase high-performance liquid chromatogra ... | 1996 | 8954770 |
| antioxidant systems and anoxia tolerance in a freshwater turtle trachemys scripta elegans. | the effects of anoxic submergence (20 h at 5 degrees c) and subsequent 24 h aerobic recovery on the antioxidant systems of six organs were examined in freshwater turtles, trachemys scripta elegans. both xanthine oxidase and xanthine dehydrogenase were detected in turtle tissues with xanthine oxidase composing 36-75% of the total activity. turtle organs displayed high constitutive activities of catalase (cat), superoxide dismutase (sod), and alkyl hydroperoxide reductase (ahr). measurements of li ... | 1997 | 9144333 |
| epithelial localization of a reptilian na+/h+ exchanger homologous to nhe-1. | basolateral membranes of turtle (pseudemys scripta) colon epithelial cells exhibit robust na+/h+ exchange activity that can be activated by cell shrinkage and is blocked by amiloride [m. a. post and d. c. dawson. am. j. physiol. 262 cell physiol. 31):c1089-c1094, 1992]. the colonic epithelium actively absorbs na+ and secretes k+ and hco3-, but the role of basolateral na+/h+ exchange, if any, in transepithelial transport is unknown. the current studies were undertaken to identify the gene product ... | 1997 | 9227498 |
| membrane properties and monosynaptic retinal excitation of neurons in the turtle accessory optic system. | using an eye-attached isolated brain stem preparation of a turtle, pseudemys scripta elegans, in conjunction with whole cell patch techniques, we recorded intracellular activity of accessory optic system neurons in the basal optic nucleus (bon). this technique offered long-lasting stable recordings of individual synaptic events. in the reduced preparation (most of the dorsal structures were removed), large spontaneous excitatory synaptic inputs [excitatory postsynaptic potentials (epsps)] were f ... | 1997 | 9307099 |
| cellular bioavailability of natural hormones and environmental contaminants as a function of serum and cytosolic binding factors. | environmental contaminants have been reported to function as hormone mimics in various wildlife species. to investigate a potential mechanism for the interaction of contaminants with the endocrine system, we evaluated the cellular bioavailability of numerous chemicals. hormone binding proteins from oviductal cytosol of the american alligator (alligator mississippiensis) and yellow-bellied turtle (trachemys scripta) were used in competitive binding assays with [3h] 17 beta-estradiol. most of the ... | 1998 | 9460179 |
| etiology of ovarian failure in blepharophimosis ptosis epicanthus inversus syndrome: foxl2 is a conserved, early-acting gene in vertebrate ovarian development. | blepharophimosis ptosis epicanthus inversus syndrome (bpes) is a human disorder caused by mutations in the forkhead transcription factor gene foxl2 and is characterized by facial dysmorphology combined in some cases with ovarian failure. to better understand the role of foxl2 in the etiology of ovarian failure in bpes, we examined its expression in embryonic ovaries of mice, chickens, and red-eared slider turtles, representatives of three phylogenetically distant vertebrate groups that have diff ... | 2003 | 12810580 |
| microvascularization of the cerebellum in the turtle, pseudemys scripta elegans (reptilia). a scanning electron microscope study of microvascular corrosion casts, including stereological measurements. | cerebellar blood supply and microvascular patterns were studied in 12 freshwater turtles pseudemys scripta elegans by scanning electron microscopy (sem) of microvascular corrosion casts and histology. vascular densities were estimated by point counting methods from casts and thin sections (7 microns). short a2-arterioles and recurrent branches from a3-arterioles supply the capillary bed of the molecular layer, while v2 and v3 venules drain it. the purkinje cell layer is supplied by horizontal br ... | 1995 | 7726392 |
| estrogen downregulation of albumin and a 170-kda serum protein in the turtle, trachemys scripta. | we examined changes in serum protein composition after estradiol-17 beta treatment of ovariectomized female trachemys scripta, with the objective of identifying proteins that are repressed by estrogen. the experimental protocol was validated by measuring serum estradiol-17 beta levels with a specific radioimmunoassay. control turtle sera contained little or no estradiol-17 beta (mean = 25.8 pg/ml) while estrogen-treated turtle sera had elevated estradiol-17 beta levels (mean = 333.3 pg/ml). estr ... | 1995 | 7789749 |
| atrial natriuretic factor in the freshwater turtle pseudemys scripta: a partial characterization. | the presence of natriuretic and vasorelaxant materials in the atria and ventricles of a chelonian reptile, the freshwater turtle pseudemys scripta, was verified and the active substance partially characterized. crude atrial and ventricular extracts were acutely natriuretic and diuretic when administered to anesthetized rats increasing sodium excretion 23.5 +/- 7.9 and 5.11 +/- 18 microm na/10 min/mg extract, respectively. although atrial extracts were relatively more natriuretic than ventricular ... | 1994 | 7851726 |
| juvenile turtles for mosquito control in water storage tanks. | juvenile turtles, trachemys scripta, provided highly effective control of mosquito larvae in cement tanks (pilas) where water was stored for household cleaning. when single turtles were introduced to tanks with histories of high mosquito production, nearly all turtles remained in good health and no mosquito larvae survived to the pupal stage. families welcome turtles in their water storage containers in honduras. humane conditions for turtles can be assured by providing small quantities of table ... | 1993 | 7902872 |
| developmental synergism of steroidal estrogens in sex determination. | gonadal sex in the red-eared slider turtle, trachemys scripta, is determined by incubation temperature during embryonic development. evidence suggests that temperature determines sex by influencing steroid hormone metabolism and/or sensitivity: steroidogenic enzyme inhibitors or exogenous sex steroid hormones and their man-made analogs override (or enhance) temperature effects on sex determination. specifically, nonaromatizable androgens and aromatase inhibitors induce testis differentiation at ... | 1999 | 9924002 |
| identification and structural characterization of a novel member of the vitamin d binding protein family. | the apparent high degree of homology of a blood protein with a unique dual binding affinity for two distinct hormones, thyroxin (t4) and vitamin d, isolated from a turtle, trachemys scripta (family emydidae) and mammalian vitamin d binding protein (dbp) prompted further interspecific comparison to better understand the structure of functional binding sites. using polymerase-chain reaction (pcr) with primers derived from the putative nucleotide sequences encoding peptides from the degradation of ... | 1998 | 9972311 |
| characterization of thyroid hormone 5'-monodeiodinase activity in the turtle (trachemys scripta). | thyroid hormone metabolism by 5'-monodeiodinase enzymes (5'md) was characterized in peripheral tissues of the turtle, trachemys scripta, and compared with activity measured in the rat. based on differences in ph dependence, sensitivity to inhibitors, substrate affinity, and cofactor requirements, at least two types of enzyme activities have been identified in the turtle. a 5'md activity was measured in liver and kidney microsomal fractions that exhibits inhibition by 2n-propyl-6-thiouracil (ptu) ... | 1999 | 10068496 |
| identification of renal podocytes in multiple species: higher vertebrates are vimentin positive/lower vertebrates are desmin positive. | we sought to characterize podocytes in the kidneys of numerous species from amphibians to mammals because of the pivotal function of these cells in renal diseases. for this purpose, intermediate filament (if) proteins of podocytes were examined by immunofluorescence microscopy using antibodies against vimentin, cytokeratins, and desmin. these staining patterns were then compared to those of parietal cells of bowman's capsule and tubular cells of the first portion of the proximal tubule from the ... | 1999 | 10090571 |
| embryonic development of connections in turtle pallium. | we are interested in similarities and conserved mechanisms in early development of the reptilian and mammalian thalamocortical connections. we set out to analyse connectivity in embryonic turtle brains (pseudemys scripta elegans, between stages 17 and 25), by using carbocyanine dye tracing. from the earliest stages studied, labelling from dorsal and ventral thalamus revealed backlabelled cells among developing thalamic fibres within the lateral forebrain bundle and striatum, which had similar mo ... | 1999 | 10464368 |
| warm-blooded isochore structure in nile crocodile and turtle. | the genomes of warm-blooded vertebrates are characterized by a strong heterogeneity in base composition, with gc-rich and gc-poor isochores. the gc content of sequences, especially in third codon positions, is highly correlated with that of the isochore they are embedded in. in amphibian and fish genomes, gc-rich isochores are nearly absent. thus, it has been proposed that the gc increase in a part of mammalian and avian genomes represents an adaptation to homeothermy. to test this selective hyp ... | 1999 | 10555283 |
| chromosome translocations in turtles: a biomarker in a sentinel animal for ecological dosimetry. | nonhuman organisms are being exposed to ionizing radiations at radionuclide-contaminated sites around the world. direct methods are seldom available for measuring biologically relevant doses received by these organisms. here we extend biological dosimetry techniques, which are much better developed for humans and a few other mammalian species, to a nonmammalian species. turtles were chosen because a long-lived animal would best serve the need for low-level, chronic exposure conditions. we chose ... | 2000 | 10825750 |