| visual cortex in a reptile, the turtle (pseudemys scripta and chrysemys picta). | | 1977 | 884523 |
| seasonal changes in testicular structure and function and the effects of gonadotropins in the freshwater turtle, chrysemys picta. | | 1976 | 992355 |
| estrogen-binding proteins in the oviduct of the turtle, chrysemys picta: evidence for a receptor species. | estradiol-binding proteins in the reproductive tract of the turtle, chrysemys picta, were characterized. cytosol was prepared from the oviducts of mature female turtles, and estradiol binding was measured using charcoal adsorption and glycerol density gradient centrifugation. a sex steroid-binding protein (sbp) similar to that found in turtle plasma was demonstrated in oviduct cytosol. the characteristics of this sbp-like binding were as follows: ka = 10(8) m-1; capacity, 10(-12) mol/mg protein; ... | 1979 | 499079 |
| ultrastructure of the dorsal lateral geniculate complex in turtles of the genera pseudemys and chrysemys. | the ultrastructure of the dorsal lateral geniculate complex in the turtles pseudemys scripta elegans and chrysemys picta belli has been studied. the majority of neurons have somata situated in a cell plate that forms the medial face of the complex. relatively few synaptic contacts occur on the somata of cell plate neurons, but three types of axon terminals contact their proximal dendrites as they course through the cell plate. the most frequent are terminals with clear, round synaptic vesicles t ... | 1986 | 3594200 |
| proceedings: the influence of mammalian gonadotrophins injected in vivo on testicular function in the normal and hypophysectomized male turtle (chrysemys picta). | | 1975 | 1151260 |
| proceedings: influence of mammalian and avian gonadotrophins and prolactin on steroidogenesis in turtle (chrysemys picta) follicular and luteal tissues. | | 1975 | 1151223 |
| the effects of induced cold torpor and time of year on blood coagulation in pseudemys scripta elegans and chrysemys picta belli. | | 1975 | 236129 |
| the origin and distribution of catecholaminergic axon terminals in the cerebral cortex of the turtle (chrysemys picta). | | 1974 | 4423150 |
| behavior of the turtle (chrysemys picta picta) in simultaneous, successive, and behavioral contrast situations. | | 1974 | 4412173 |
| morphological organization of monoamine-containing neurons in the hypothalamus of the painted turtle (chrysemys picta). | | 1974 | 4132970 |
| normal embryonic stages of the western painted turtle, chrysemys picta bellii. | | 1973 | 4753442 |
| demonstration of a catecholaminergic pathway from the midbrain to the strio-amygdaloid complex in the turtle (chrysemys picta). | | 1973 | 4716140 |
| distribution of monoamine-containing nerve terminals in the brain of the painted turtle, chrysemys picta. | | 1973 | 4700507 |
| effects of cold exposure on cardiac metabolism of the turtle pseudemys (chrysemys) picta. | | 1973 | 4686499 |
| the effects of induced cold torpor on atpase activity of the turtle, pseudemys (chrysemys) picta. | | 1972 | 4260488 |
| antidiuretic effect of arginine vasotocin in the western painted turtle (chrysemys picta belli). | | 1972 | 5009670 |
| steroid biosynthesis by painted turtle (chrysemys picta picta) adrenals. | | 1972 | 5021414 |
| behavioral visual functions for chrysemys picta picta. preferences and frequency responses. | | 1972 | 4653341 |
| ionoregulatory responses of the hypophysectomized turtle chrysemys picta to osmotic stresses. | | 1971 | 5128299 |
| shock-induced threat and biting by the turtle. | shock-induced biting and threat by the male painted turtle (chrysemys picta marginata) were studied in three experiments. when restrained facing each other, the turtles threatened and bit other turtles in response to electric shock. shock alone caused turtles to threaten an unshocked turtle; the movements of a shocked turtle were sufficient to cause an unshocked but restrained turtle to threaten. when the turtles were free to move, they avoided an encounter when shocked, even reversing a strong ... | 1971 | 16811550 |
| occurrence and distribution of monoamine-containing neurons in the brain of the painted turtle, chrysemys picta. | | 1971 | 5140519 |
| behavior of the aquatic turtle (chrysemys picta) on a modified visual cliff. | | 1971 | 5159009 |
| a structural and functional analysis of walking in the turtle, chrysemys picta marginata. | | 1971 | 5135653 |
| seasonal incidence of parasitism in the painted turtle, chrysemys picta marginata agassiz. | | 1967 | 6068191 |
| relationship between cardiac glycogen and tolerance to anoxia in the western painted turtle, chrysemys picta bellii. | | 1967 | 6050000 |
| adenosine triphosphatase activity within heart homogenates of the turtle, chrysemys picta. | | 1967 | 4226744 |
| in vivo and in vitro responses to gonadotropin releasing hormone in the turtle, chrysemys picta, in relation to sex and reproductive stage. | in vivo and in vitro responsiveness to gonadotropin releasing hormone (gnrh) was studied in the turtle, chrysemys picta, after manipulation of reproductive condition by temperature: warm temperatures (28 degrees) induced testicular growth and ovarian regression compared to cold (17 degrees) treatment. only males (and primarily from cold treatment) responded to gnrh injection (40 micrograms/100 g body wt intracardiac); correlated increases occurred in plasma lh and testosterone. effects of gnrh ( ... | 1985 | 3932124 |
| the gastro-entero-pancreatic system of the turtle, chrysemys picta. | pancreatic endocrine cells were stained immunocytochemically for insulin, glucagon, somatostatin and pancreatic polypeptide by the pap technique or sequentially for two hormones by the pap followed by an indirect immunogold procedure. pancreatic endocrine cells of chrysemys are found scattered as single cells or small aggregates throughout the exocrine parenchyma; only the splenic region shows islets consisting of a b cell core surrounded by a loose mantle of a cells and occasional d cells. pp c ... | 1985 | 3913912 |
| renewal of intestinal epithelium in the freshwater turtle, chrysemys picta. | | 1964 | 14153303 |
| transport of monosaccharides by intestinal segments of the painted turtle, chrysemys picta. | | 1961 | 13894354 |
| metabolism of chrysemys picta during fasting and during cold torpor. | | 1957 | 13411235 |
| effects of induced cold torpor on blood of chrysemys picta. | | 1956 | 13362596 |
| the development of the shoulder region of the turtle, chrysemys picta marginata, with special reference to the primary musculature. | | 1947 | 20287830 |
| the viability of nearctic freshwater turtles submerged in anoxia and normoxia at 3 and 10 degrees c. | survival times of temperature-acclimated freshwater turtles submerged in normoxic and anoxic water were determined. juvenile chrysemys scripta from alabama and adult chrysemys picta bellii from wisconsin exhibited the maximal survival times of the 10 species and subspecies investigated, both being able to survive at least a half-year of submergence at 3 degrees c in normoxic water. minimal viability was exhibited by sternotherus odoratus and trionyx spiniferus submerged in anoxia at 10 degrees c ... | 1985 | 2863050 |
| [hemoglobins of reptiles. expression of alpha-d-genes in the turtles, chrysemys picta bellii and phrynops hilarii (testudines)]. | the hemoglobins of two turtles (testudines)--chrysemys picta bellii (suborder cryptodira) and phrynops hilarii (suborder pleurodira)--were investigated. in both specimens we found two hemoglobin components with two distinct alpha-chains. the alpha-chains of the component hbd of chrysemys picta bellii and of the component cii of phyrynops hilarii belong to the alpha d-type, which has so far been reported to occur only in birds. the complete amino-acid sequences of both alpha d-chains are presente ... | 1984 | 6519642 |
| high affinity binding of [3h]r5020 and [3h]progesterone by putative progesterone receptors in cytosol and nuclear extract of turtle oviduct. | the purpose of this investigation was to identify and characterize putative cytosolic and nuclear forms of progesterone receptor in the female reproductive tract of a turtle, chrysemys picta. a dextran-coated charcoal adsorption assay and dna-cellulose affinity chromatography were used as the primary methodologies with [3h]r5020 [3h-labeled 17 alpha-dimethyl-19-norpregna-4,9-diene-3,20-dione) and [3h]progesterone (p4) as the ligands. the receptor was of high affinity (kd = 4.7 x 10(-10) m for [3 ... | 1984 | 6537807 |
| characterization of an estrogen receptor in the turtle testis. | using dna-cellulose affinity chromatography, an estrogen-binding component having the properties of a classical estrogen receptor was characterized from testicular cytosol of the freshwater turtle, chrysemys picta. this putative cytoplasmic receptor exhibited high affinity (kd = 7.0 x 10(-10) m), low capacity (1-4 fmol/mg protein), and steroid binding that was specific for estrogens. it was not present in plasma, muscle, kidney, or lung. a temperature-dependent conversion of turtle testicular es ... | 1983 | 6654030 |
| intracellular and extracellular acid-base and electrolyte status of submerged anoxic turtles at 3 degrees c. | specimens of fresh water turtles (chrysemys picta bellii) were acclimated to 3 degrees c and then submerged in completely anoxic water for time periods of up to 12 weeks. blood withdrawn via indwelling arterial catheters was analysed for plasma ph, pco2, bicarbonate concentration, [lactate], [na+], [k+], [ca2+] and [mg2+], and tissue samples of skeletal muscle, liver and cardiac muscle were excised. samples of skeletal muscle were analysed for intracellular ph (dmo), [lactate], [na+], [k+], [ca2 ... | 1983 | 6635379 |
| the effects of lesions of telencephalic visual structures on visual discriminative performance in turtles (chrysemys picta picta). | ascending thalamotelencephalic visual pathways that terminate in specific telencephalic regions have been described in all reptiles studied. although the anatomical data suggests that such telencephalic regions may play a role in visual processing in reptiles, few behavioral data are available. in the present study, the effects of destruction of either the core nucleus (cn) of the dorsal ventricular ridge (telencephalic terminus of the tectothalamofugal pathway) or the dorsal cortex (telencephal ... | 1983 | 6886065 |
| estradiol binding activity in epididymal cytosol of the turtle, chrysemys picta. | estrogen binding activity was investigated in the epididymis of the turtle, chrysemys picta using dna-cellulose affinity chromatography. a component binding estradiol-17 beta specifically with high affinity (kd:8.0 x 10(-10) m) and limited capacity (20 fmol/mg protein) was demonstrated in the epididymal cytosol. in addition, binding of estradiol-17 beta was sensitive to excess (100-fold) diethylstilbestrol or natural estrogens (estradiol-17 beta, estrone, and estriol) but not to progesterone or ... | 1983 | 6884762 |
| effect of chronic cold and submergence on blood oxygen transport in the turtle, chrysemys picta. | whole blood oxygen equilibrium curves (o2ec's) and related hematologic properties are reported for the turtle chrysemys picta exposed to two experimental conditions. summer turtles were maintained at 24 degrees c with free access to air; winter turtles were submerged for 4-12 wk in n2-bubbled water at 3 degrees c. half-saturation po2's at 3 degrees c for blood from summer and winter animals were 4.1 and 4.5 torr, respectively. at 24 degrees c, summer and winter p50's were 20.2 and 22.7 torr, res ... | 1983 | 6622863 |
| influence of the hydric environment on sexual differentiation of turtles. | phenotypic sex of hatching painted turtles (chrysemys picta), a species known to exhibit temperature-dependent sex determination, is influenced by the hydric environment to which developing embryos are subjected. hatching sex ratios vary significantly over the range of 26.5 to 28.5 degrees c due to effects of the hydric environment. | 1983 | 6886668 |
| the effects of lesions of nucleus rotundus on visual intensity difference thresholds in turtles (chrysemys picta). | intensity difference thresholds were assessed behaviorally in 7 painted turtles (chrysemys picta) before and after lesions of nucleus rotundus thalami or control lesions. three subjects with control lesions and two subjects with slight bilateral damage to nucleus rotundus showed no permanent elevation of threshold postoperatively. in contrast, two subjects with severe damage to nucleus rotundus showed threshold elevations postoperatively and did not recover with further training. the impairment ... | 1983 | 6850289 |
| visual activity in the telencephalon of the painted turtle, chrysemys picta. | multiple unit activity in response to visual stimulation was recorded in the following telencephalic areas of the painted turtle: lateral and medial divisions of the dorsal cortex, lateral and medial divisions of the dorsal ventricular ridge, and the striatum. the data confirm anatomical evidence for ascending visual input to the dorsal cortex, the lateral dorsal ventricular ridge and the striatum. the identification of a new visual zone in a medial division of the dorsal ventricular ridge sugge ... | 1983 | 6839172 |
| effect of hypophysectomy and growth hormone on estrogen-induced vitellogenesis in the freshwater turtle, chrysemys picta. | | 1982 | 7141208 |
| the role of vagal afferent information and hypercapnia in control of the breathing pattern in chelonia. | the normal breathing pattern of the turtle, chrysemys picta (schneider), consists of periods of continuous breathing interspersed with periods of breath holding. during each ventilatory period respiratory frequency and tidal volume are controlled independently. there is a large variability in inspiratory and expiratory gas-flow rates yet tidal volumes are maintained within narrow limits by adjustments of the lengths of the active inspiratory and expiratory intervals. lung volume information carr ... | 1980 | 7420020 |
| the effects of extensive forebrain lesions on visual discriminative performance in turtles (chrysemys picta picta). | though anatomical research has demonstrated major ascending telecephalically directed visual channels in reptiles, little behavioral research has examined reptilian forebrain visual functions. the present study reports the effects of extensive forebrain lesions, involving either severe destruction of dorsal thalamus or disruption of the fibers of the lateral forebrain bundle (by lesions of the basolateral telecephalon), upon visual discriminative performance in the turtle. such lesions, which ex ... | 1980 | 7378794 |
| the influence of oestradiol-17beta and progesterone on the contractility of the oviduct of the turtle, chrysemys picta, in vitro. | the contractility of the oviduct of chrysemys picta (the fresh-water turtle) was studied in vitro. significant regional differences in contractile activity were observed. contractions increased in amplitude and duration and decreased in frequency from the proximal to the distal end of the oviduct. injections of oestradiol-17beta in vivo increased the amplitude of contractions and decreased the duration of the rest period in segments taken from the diatal end of the oviduct. in contrast, progeste ... | 1976 | 1255052 |
| proceedings: control of prolactin secretion in the terrapin (chrysemys picta). | | 1975 | 812938 |
| serum protein concentration changes in the turtle, chrysemys picta. | | 1965 | 5865201 |
| probability-learning by the turtle. | tested in a two-choice situation, the painted turtle, chrysemys picta picta, shows random probability-matching in visual problems and in confounded visual-spatial problems, but only maximizing or nonrandom matching (reward-following) in spatial problems. the results are compared with those of analogous experiments on fish, bird, and mammal. | 1965 | 14294140 |
| hypoxia tolerance in reptiles, amphibians, and fishes: life with variable oxygen availability. | the ability of fishes, amphibians, and reptiles to survive extremes of oxygen availability derives from a core triad of adaptations: profound metabolic suppression, tolerance of ionic and ph disturbances, and mechanisms for avoiding free-radical injury during reoxygenation. for long-term anoxic survival, enhanced storage of glycogen in critical tissues is also necessary. the diversity of body morphologies and habitats and the utilization of dormancy have resulted in a broad array of adaptations ... | 2007 | 17037980 |
| characterization of melanin-concentrating hormone (mch) and its receptor in chickens: tissue expression, functional analysis, and fasting-induced up-regulation of hypothalamic mch expression. | melanin-concentrating hormone (mch) is a neuropeptide expressed in the brain and exerts its actions through interaction with the two known g protein-coupled receptors, namely melanin-concentrating hormone receptor 1 and 2 (mchr1 and mchr2) in mammals. however, the information regarding the expression and functionality of mch and mchr(s) remains largely unknown in birds. in this study, using rt-pcr and race pcr, we amplified and cloned a mchr1-like receptor, which is named cmchr4 according to its ... | 2017 | 28300612 |
| evolution of an expanded mannose receptor gene family. | sequences of peptides from a protein specifically immunoprecipitated by an antibody, kul01, that recognises chicken macrophages, identified a homologue of the mammalian mannose receptor, mrc1, which we called mrc1l-b. inspection of the genomic environment of the chicken gene revealed an array of five paralogous genes, mrc1l-a to mrc1l-e, located between conserved flanking genes found either side of the single mrc1 gene in mammals. transcripts of all five genes were detected in rna from a macroph ... | 2014 | 25390371 |
| the hypoxia-tolerant vertebrate brain: arresting synaptic activity. | the ion channel arrest hypothesis has been the foundation of three decades of research into the underlying mechanisms of hypoxia/anoxia tolerance in several key species, including: painted turtles, goldfish, crucian carp, naked mole rats, and arctic and ground squirrels. the hypothesis originally stated that hypoxia/anoxia tolerant species ought to have fewer ion channels per area membrane and/or mechanisms to regulate the conductance of ion channels. today we can add to this and include mechani ... | 2017 | 29223874 |
| morbidity and mortality of wild turtles at a north carolina wildlife clinic: a 10-year retrospective. | the medical records from 1,847 wild turtle patients seen between 2005 and 2014 by the turtle rescue team at the north carolina state university college of veterinary medicine were analyzed. eastern box turtles (terrapene carolina carolina; n = 947), yellow-bellied sliders (trachemys scripta scripta; n = 301), cooters ( pseudemys spp.; n = 235), common snapping turtles (chelydra serpentina; n = 165), and eastern painted turtles (chrysemys picta; n = 93) made up 94.3% of all patients. patient admi ... | 2017 | 28920820 |
| lipid provisioning of turtle eggs and hatchlings: total lipid, phospholipid, triacylglycerol and triacylglycerol fatty acids. | lipid composition of eggs and hatchlings was studied in painted, snapping and blanding's turtles from western nebraska. the average total lipid proportions of the egg yolk, post-embryonic yolk and hatchling soma dry masses were high in painted turtles (29.80%, 42.16% and 14.18%, respectively) relative to snapping and blanding's turtles (egg yolk < 14%, postembryonic yolk < 17%, hatchling soma < 2%). the proportion of total egg yolk lipid used during development varied among species (painted turt ... | 1995 | 7584861 |
| steroid hormones reverse sex in turtles. | injection of estradiol benzoate into eggs of snapping turtles and painted turtles caused all embryos to develop as females. a similar but less consistent female-determining effect was associated with injection of testosterone proprionate. both species of turtles have temperature-dependent sex determination in nature, whereby embryos incubated at cool temperatures (25 degrees) develop as males and embryos incubated at warm temperatures (31 degrees) develop as females. exogenous estrogens have bee ... | 1986 | 3803892 |
| hibernating without oxygen: physiological adaptations of the painted turtle. | many freshwater turtles in temperate climates may experience winter periods trapped under ice unable to breathe, in anoxic mud, or in water depleted of o(2). to survive, these animals must not only retain function while anoxic, but they must do so for extended periods of time. two general physiological adaptive responses appear to underlie this capacity for long-term survival. the first is a coordinated depression of metabolic processes within the cells, both the glycolytic pathway that produces ... | 2002 | 12231634 |
| a genetic analogue of 'mark-recapture' methods for estimating population size: an approach based on molecular parentage assessments. | molecular polymorphisms have been used in a variety of ways to estimate both effective and local census population sizes in nature. a related approach for estimating the current size of a breeding population, explored here for the first time, is the use of genetic 'marks' reconstructed for otherwise unknown parents in paternity or maternity analyses of progeny arrays. this method provides interesting similarities and contrasts to traditional mark-recapture methods based on physical tags. to illu ... | 2001 | 11883884 |
| reversible decreases in atp and pcr concentrations in anoxic turtle brain. | a hallmark of anoxia tolerance in western painted turtles is relative constancy of tissue adenylate concentrations during periods of oxygen limitation. during anoxia heart and brain intracellular compartments become more acidic and cellular energy demands are met by anaerobic glycolysis. because changes in adenylates and ph during anoxic stress could represent important signals triggering metabolic and ion channel down-regulation we measured pcr, atp and intracellular ph in turtle brain sheets t ... | 1998 | 9828395 |
| a heme-protein-based oxygen-sensing mechanism controls the expression and suppression of multiple proteins in anoxia-tolerant turtle hepatocytes. | the o2 sensitivity of protein expression was assessed in hepatocytes from the western painted turtle. anoxic cells consistently expressed proteins of 83.0, 70.4, 42.5, 35.3, and 16.1 kda and suppressed proteins of 63.7, 48.2, 36.9, 29.5, and 17.7 kda. except for the 70.4-kda protein, this pattern was absent during aerobic incubation with 2 mm nacn, suggesting a specific requirement for o2. aerobic incubation with co2+ or ni2+ increased expression of the 42.5-, 35.3-, and 16.1-kda protein bands w ... | 1995 | 11607568 |
| effects of anoxia and graded acidosis on the levels of circulating catecholamines in turtles. | we measured circulating levels of catecholamines in painted turtles subjected to anoxia with different degrees of concomitant acidosis at 20 degrees c and in turtles subjected to long-term submergence at 3 and 10 degrees c. blood levels of both epinephrine (e) and norepinephrine (ne) increased during n2-breathing, n2/co2 breathing and submergence, with ne generally being present in higher concentrations than e. during submergence at 20 degrees c, anoxic turtles experienced an extreme acidosis an ... | 1991 | 1925113 |
| plasma ion balance of submerged anoxic turtles at 3 degrees c: the role of calcium lactate formation. | freshwater turtles, chrysemys picta bellii, were submerged in groups of 7 at 3 degrees c in o2-free water for 1, 2, 4, 8 and 12 weeks. blood samples from these turtles and from 10 normoxic turtles at 3 degrees c were analyzed for plasma concentrations of lactic acid, total co2, na+, k+, cl-, ca2+, total calcium, total magnesium and osmolality. total lactate rose during anoxia to a mean peak value of 145 mm, but the decrease in hco-3 and cl- and increase in k+ balanced less than 40% of the lactat ... | 1982 | 7146649 |
| long-term submergence at 3 degrees c of the turtle chrysemys picta bellii in normoxic and severely hypoxic water. iii. effects of changes in ambient po2 and subsequent air breathing. | western painted turtles, chrysemys picta bellii (n = 5), were maintained submerged and apneic for 90 days: days 0-21 in severely hypoxic water (po2 = 0-5 mmhg), days 22-43 in aerated water (po2 approximately 160 mmhg), and days 44-90 again in hypoxic water. from day 90 onward, the water was aerated and the turtles were allowed access to the air; water and air temperatures were maintained at 3 degrees c. arterial blood samples were taken periodically and analysed for po2, pco2, ph, [na+], [k+] [c ... | 1982 | 6806428 |
| estrogen receptors in the turtle brain. | estrogen binding activity in the cns of the freshwater turtle, chrysemys picta, was investigated using dna-cellulose affinity chromatography. an estrogen binding component (ebc) with the characteristics of an estrogen receptor species was demonstrated in the brain cytosol extracts from both sexes. this ebc exhibited high affinity (k d = 10 -10 m), low capacity (n = 0.8 to 6.0 fmol/mg cytosol protein) and binding specificity. the bound estradiol-17 beta which adhered to dna-cellulose was sensitiv ... | 1982 | 7055678 |
| thyrotropin-releasing hormone and thyrotropin in the control of thyroid function in the turtle, chrysemys picta. | | 1981 | 6793449 |
| retinal recipient nuclei in the painted turtle, chrysemys picta: an autoradiographic and hrp study. | retinofugal pathways in the painted turtle were examined with autoradiographic and hrp methods. the majority of the retinal fibers decussate at the optic chiasm and course caudally to terminate in 12 regions of the diencephalon and mesencephalon. the pars dorsalis of the lateral geniculate nucleus is the densest target in the thalamus. two nuclei dorsal to pars dorsalis--the dorsal optic and dorsal central nuclei--receive optic input. three nuclei ventral to pars dorsalis and retinal targets--th ... | 1981 | 7263950 |
| a sex-steroid-binding protein in the plasma of the freshwater turtle, chrysemys picta. | | 1980 | 6777238 |
| adrenalectomy of the painted turtle (chrysemis picta belli): effect on lonoregulation and tissue glycogen. | | 1970 | 5423002 |
| a new slider turtle (testudines: emydidae: deirochelyinae:trachemys) from the late hemphillian (late miocene/early pliocene) of eastern tennessee and the evolution of the deirochelyines. | trachemys(testudines: emydidae) represents one of the most well-known turtle genera today. the evolution oftrachemys, while being heavily documented with fossil representatives, is not well understood. numerous fossils from the late hemphillian gray fossil site (gfs) in northeastern tennessee help to elucidate its evolution. the fossiltrachemysat the gfs represent a new species. the new taxon,trachemys haugrudi, is described, and currently represents the most thoroughly described fossil emydid s ... | 2018 | 29456887 |
| navigating oxygen deprivation: liver transcriptomic responses of the red eared slider turtle to environmental anoxia. | the best facultative anaerobes among vertebrates are members of the genera trachemys (pond slider turtles) and chrysemys (painted turtles), and are able to survive without oxygen for up to 12 to 18 weeks at ∼3 °c. in this study, we utilized rnaseq to profile the transcriptomic changes that take place in response to 20 hrs of anoxia at 5 °c in the liver of the red eared slide turtle (trachemys scripta elegans). sequencing reads were obtained from at least 18,169 different genes and represented a ... | 2019 | 31788367 |
| composition and divergence of coronavirus spike proteins and host ace2 receptors predict potential intermediate hosts of sars-cov-2. | from the beginning of 2002 and 2012, severe respiratory syndrome coronavirus (sars-cov) and middle east respiratory syndrome coronavirus (mers-cov) crossed the species barriers to infect humans, causing thousands of infections and hundreds of deaths, respectively. currently, a novel coronavirus (sars-cov-2), which has become the cause of the outbreak of coronavirus disease 2019 (covid-19), was discovered. until 18 february 2020, there were 72 533 confirmed covid-19 cases (including 10 644 severe ... | 2020 | 32100877 |
| joint estimation of growth and survival from mark-recapture data to improve estimates of senescence in wild populations. | understanding age-dependent patterns of survival is fundamental to predicting population dynamics, understanding selective pressures, and estimating rates of senescence. however, quantifying age-specific survival in wild populations poses significant logistical and statistical challenges. recent work has helped to alleviate these constraints by demonstrating that age-specific survival can be estimated using mark-recapture data even when age is unknown for all or some individuals. however, previo ... | 2020 | 31471965 |
| small non-coding rna expression and vertebrate anoxia tolerance. | background: extreme anoxia tolerance requires a metabolic depression whose modulation could involve small non-coding rnas (small ncrnas), which are specific, rapid, and reversible regulators of gene expression. a previous study of small ncrna expression in embryos of the annual killifish austrofundulus limnaeus, the most anoxia-tolerant vertebrate known, revealed a specific expression pattern of small ncrnas that could play important roles in anoxia tolerance. here, we conduct a comparative stud ... | 2018 | 30042786 |
| mitochondrial matrix ph acidifies during anoxia and is maintained by the f1fo-atpase in anoxia-tolerant painted turtle cortical neurons. | the western painted turtle (chrysemys picta bellii) can survive extended periods of anoxia via a series of mechanisms that serve to reduce its energetic needs. central to these mechanisms is the response of mitochondria, which depolarize in response to anoxia in turtle pyramidal neurons due to an influx of k+. it is currently unknown how mitochondrial matrix ph is affected by this response and we hypothesized that matrix ph acidifies during anoxia due to increased k+/h+ exchanger activity. inhib ... | 2019 | 30984533 |
| comparative analysis of glucagonergic cells, glia, and the circumferential marginal zone in the reptilian retina. | retinal progenitors in the circumferential marginal zone (cmz) and müller glia-derived progenitors have been well described for the eyes of fish, amphibians, and birds. however, there is no information regarding a cmz and the nature of retinal glia in species phylogenetically bridging amphibians and birds. the purpose of this study was to examine the retinal glia and investigate whether a cmz is present in the eyes of reptilian species. we used immunohistochemical analyses to study retinal glia, ... | 2016 | 26053997 |
| geographic variation in thermal sensitivity of early life traits in a widespread reptile. | taxa with large geographic distributions generally encompass diverse macroclimatic conditions, potentially requiring local adaptation and/or phenotypic plasticity to match their phenotypes to differing environments. these eco-evolutionary processes are of particular interest in organisms with traits that are directly affected by temperature, such as embryonic development in oviparous ectotherms. here we examine the spatial distribution of fitness-related early life phenotypes across the range of ... | 2019 | 30891217 |
| karyotypic evolution of sauropsid vertebrates illuminated by optical and physical mapping of the painted turtle and slider turtle genomes. | recent sequencing and software enhancements have advanced our understanding of the evolution of genomic structure and function, especially addressing novel evolutionary biology questions. yet fragmentary turtle genome assemblies remain a challenge to fully decipher the genetic architecture of adaptive evolution. here, we use optical mapping to improve the contiguity of the painted turtle (chrysemys picta) genome assembly and use de novo fluorescent in situ hybridization (fish) of bacterial artif ... | 2020 | 32806747 |
| evolutionary conservation of transferrin genomic organization and expression characterization in seven freshwater turtles. | serum transferrin (tf), encoding an iron-binding glycoprotein, has been revealed to play important roles in iron transportation and immune response, and it also has been demonstrated to be valuable for phylogenetic analysis in vertebrates. however, the evolutionary conservation, expression profiles and positive selection of transferrin genes among freshwater turtle species remain largely unclear. here, the genomic dna and coding sequences of transferrin genes were cloned and characterized in sev ... | 2018 | 30392910 |
| physiology of hibernation under the ice by turtles and frogs. | successful overwintering under ice by an air-breathing vertebrate requires either effective aquatic respiration if dissolved o(2) is available or the capacity for prolonged anaerobic metabolism if o(2) supplies are limiting. frogs can remain aerobic for many weeks when submerged at low temperature, even at water po(2) as low as 30 mmhg, but are unable to survive even 1 week in anoxic water. fuel reserves of hibernating frogs limit aerobic submergence, whereas acidosis may limit anoxic submergenc ... | 2010 | 20535765 |
| among-family variation for environmental sex determination in reptiles. | unlike birds and mammals, in many reptiles the temperature experienced by a developing embryo determines its gonadal sex. to understand how temperature-dependent sex determination (tsd) evolves, we must first determine the nature of genetic variation for sex ratio. here, we analyze among-family variation for sex ratio in three tsd species: the american alligator (alligator mississipiensis), the common snapping turtle (chelydra serpentina) and the painted turtle (chrysemys picta). significant fam ... | 1998 | 28565384 |
| becoming creatures of habit: among- and within-individual variation in nesting behaviour shift with age. | the quantification of repeatability has enabled behavioural and evolutionary ecologists to assess the heritable potential of traits. for behavioural traits that vary across life, age-related variation should be accounted for to prevent biasing the microevolutionary estimate of interest. moreover, to gain a mechanistic understanding of ontogenetic variation in behaviour, among- and within-individual variance should be quantified across life. we leveraged a 30-year study of painted turtles (chryse ... | 2020 | 32897610 |
| immunosenescence and its influence on reproduction in a long-lived vertebrate. | immunosenescence is a well-known phenomenon in mammal systems, but its relevance in other long-lived vertebrates is less understood. further, the influence of age and reproductive effort on immune function in long-lived species can be challenging to assess, as long-term data are scarce and it is often difficult to sample the oldest age classes. we used the painted turtle (chrysemys picta) to test hypotheses of immunosenescence and a trade-off between reproductive output and immune function in a ... | 2020 | 32376708 |
| a nonparametric comparison of monomolecular growth curves: application to western painted turtle data. | intractable distributional assumptions are generated in parametric analyses comparing groups of subjects described by nonlinear growth models. the distributional situation becomes more complex when pointwise mean curves best describe group growth (instead of curves based on mean parameters). an interval specific randomization test is developed to handle monomolecular growth models. the need for the technique was motivated by a study describing longitudinal growth data from the annuli on abdomina ... | 2006 | 2807647 |
| interdigital cell death during limb development of the turtle and lizard with an interpretation of evolutionary significance. | cell death accompanies the formation of free digits in birds and mammals. however, in species with webbing between the adult digits, little or no cell death occurs in the prospectively webbed region of the developing interdigit. cell death does not occur during the formation of free digits in amphibians. in this paper we report that cell death accompanies the formation of the digits in snapping and painted turtles and in the skink (a lizard). we conclude that cell death accompanying the formatio ... | 1977 | 915430 |
| sex and incubation temperature independently affect embryonic development and offspring size in a turtle with temperature-dependent sex determination. | developmental environments can have lasting effects on an individual's phenotype. in many reptiles, for example, egg incubation temperature permanently determines offspring sex (temperature-dependent sex determination, tsd) and also influences a suite of morphological, physiological, and behavioral traits. thus, the contributions of sex and incubation temperature to phenotypic variation are difficult to identify because these factors are confounded under tsd. we used chemical manipulations to ex ... | 2020 | 31808735 |
| coelioscopic orchiectomy can be effectively and safely accomplished in chelonians. | coelioscopic orchiectomy was performed in 27 male turtles (25 juvenile to adult red-eared sliders (trachemys scripta elegans), one adult eastern painted turtle (chrysems picta picta), and one juvenile male yellow-spotted amazon river turtle (podocnemis unifilis)). orchiectomy was conducted under coelioscopic visualisation using ligation and transection of the mesorchium, or transection of the mesorchium with monopolar radiosurgical scissors. in 22 cases, bilateral orchiectomy was performed throu ... | 2013 | 23559425 |
| coelioscopic-assisted prefemoral oophorectomy in chelonians. | to describe a coelioscopic-assisted prefemoral oophorectomy technique for use in chelonians. | 2007 | 17397348 |
| genetic polymorphisms in aromatase (cyp19a1) are not associated with gonadal phenotypes in red-eared slider turtle hatchlings developed at a pivotal temperature. | embryonic gonad sex in many reptilian species is determined by the incubation temperature of the egg, a differentiation process known as temperature-dependent sex determination (tsd). incubation at the pivotal temperature (pvt) results in approximately an equal number of offspring of both sexes. we investigated the potential contribution of genetic variations that drives the gonadal differentiation into testes or ovaries under this temperature in the red-eared slider turtle (trachemys scripta). ... | 2017 | 28445889 |
| tissue glycogen and extracellular buffering limit the survival of red-eared slider turtles during anoxic submergence at 3 degrees c. | the goal of this study was to identify the factors that limit the survival of the red-eared slider turtle trachemys scripta during long-term anoxic submergence at 3 degrees c. we measured blood acid-base status and tissue lactate and glycogen contents after 13, 29, and 44 d of submergence from ventricle, liver, carapace (lactate only), and four skeletal muscles. we also measured plasma ca(2+), mg(2+), na(+), k(+), cl(-), inorganic phosphate (p(i)), lactate, and glucose. after 44 d, one of the si ... | 2016 | 16826499 |
| evaluation of a multiplexed, multispecies nuclear receptor assay for chemical hazard assessment. | sensitivity to potential endocrine disrupting chemicals in the environment varies across species and is influenced by sequence conservation of their nuclear receptor targets. here, we evaluated a multiplexed, in vitro assay testing receptors relevant to endocrine and metabolic disruption from five species. the trans-factorial™ system of human nuclear receptors was modified to include additional species: mouse (mus musculus), frog (xenopus laevis), zebrafish (danio rerio), chicken (gallus gallus) ... | 2020 | 33049310 |
| high prevalence of subclinical frog virus 3 infection in freshwater turtles of ontario, canada. | ranaviruses have been associated with chelonian mortality. in canada, the first two cases of ranavirus were detected in turtles in 2018 in ontario, although a subsequent survey of its prevalence failed to detect additional positive cases. to confirm the prevalence of ranavirus in turtles in ontario, we used a more sensitive method to investigate if lower level persistent infection was present in the population. here we report results via a combination of qpcr, pcr, sanger sequencing and genome s ... | 2020 | 32174301 |
| detecting trends in body size: empirical and statistical requirements for intraspecific analyses. | attributing biological explanations to observed ecogeographical and ecological patterns require eliminating potential statistical and sampling artifacts as alternative explanations of the observed patterns. here, we assess the role of sample size, statistical power, and geographic inclusivity on the general validity and statistical significance of relationships between body size and latitude for 3 well-studied species of turtles. we extend those analyses to emphasize the importance of using stat ... | 2019 | 31616479 |
| colonization and usage of an artificial urban wetland complex by freshwater turtles. | conservation authorities invest heavily in the restoration and/or creation of wetlands to counteract the destruction of habitat caused by urbanization. monitoring the colonization of these new wetlands is critical to an adaptive management process. we conducted a turtle mark-recapture survey in a 250 ha artificially created wetland complex in a large north american city (toronto, ontario). we found that two of ontario's eight native turtle species (snapping turtle (sn), chelydra serpentina, and ... | 2018 | 30123718 |
| phenotypic plasticity of nest timing in a post-glacial landscape: how do reptiles adapt to seasonal time constraints? | life histories evolve in response to constraints on the time available for growth and development. nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. we used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snap ... | 2017 | 27870008 |
| the development and homology of the chelonian carpus and tarsus. | the long-standing controversies involving the number and homologies of the elements of the carpus and tarsus of turtles are reviewed from a developmental perspective. the analysis is based on a detailed description of the chondrogenesis of the carpus and tarsus in the species chelydra serpentina and chrysemys picta. the first stage described is the differentiation of a y-shaped chondrogenetic condensation involving the humerus (femur)-radius/ ulna (tibia/fibula). this stage is followed by the ea ... | 1985 | 30005563 |
| alternative splicing and thermosensitive expression of dmrt1 during urogenital development in the painted turtle, chrysemys picta. | the doublesex and mab-3 related transcription factor 1 (dmrt1) is a highly conserved gene across numerous vertebrates and invertebrates in sequence and function. small aminoacid changes in dmrt1 are associated with turnovers in sex determination in reptiles. dmrt1 is upregulated in males during gonadal development in many species, including the painted turtle, chrysemys picta, a reptile with temperature-dependent sex determination (tsd). dmrt1 is reported to play different roles during sex deter ... | 2020 | 32219017 |
| development-specific transcriptomic profiling suggests new mechanisms for anoxic survival in the ventricle of overwintering turtles. | oxygen deprivation swiftly damages tissues in most animals, yet some species show remarkable abilities to tolerate little or even no oxygen. painted turtles exhibit a development-dependent tolerance that allows adults to survive anoxia approximately four times longer than hatchlings: adults survive ∼170 days and hatchlings survive ∼40 days at 3°c. we hypothesized that this difference is related to development-dependent differences in ventricular gene expression. using a comparative ontogenetic a ... | 2020 | 31862849 |
| analysis of the microbiota in the fecal material of painted turtles (chrysemys picta). | we used high-throughput sequencing analysis, which targeted the hypervariable v3-v4 region of the bacterial 16s rrna gene, to investigate the microbiota in fecal material from ten wild painted turtles (chrysemys picta) captured in southeastern wisconsin. the most predominant bacterial phylum detected in all samples was the firmicutes (relative abundance for all samples 96.4% to 68.3%). the next most predominant phylum was bacteroidetes (relative abundance for all samples 23.9% to 7.8%) in eight ... | 2020 | 31642965 |