| modeling commercial freshwater turtle production on us farms for pet and meat markets. | freshwater turtles are being exploited for meat, eggs, traditional medicine, and pet trade. as a response, turtle farming became a booming aquaculture industry in the past two decades, specifically in the southeastern states of the united states of america (us) and across southeast asia. however, us turtle farms are currently producing turtles only for the pet trade while commercial trappers remain focused on catching the largest individuals from the wild. in our analyses we have created a biolo ... | 2015 | 26407157 |
| preparation and application of an innovative thrombocyte/leukocyte-enriched plasma to promote tissue repair in chelonians. | platelet concentrates are widely used in mammalian regenerative medicine to improve tissue healing. chelonians (testudines) would benefit from the application of thrombocyte preparations to regenerate damaged tissues, since traumatic injuries are leading causes of morbidity and mortality for both wild-living and domesticated animals. the aim of this study was to establish a protocol that optimized the recovery of the thrombocytes from blood samples and to show the efficacy of thrombocyte-enriche ... | 2015 | 25901960 |
| distribution and innervation of putative peripheral arterial chemoreceptors in the red-eared slider (trachemys scripta elegans). | peripheral arterial chemoreceptors have been isolated to the common carotid artery, aorta, and pulmonary artery of turtles. however, the putative neurotransmitters associated with these chemoreceptors have not yet been described. the goal of the present study was to determine the neurochemical content, innervations, and distribution of putative oxygen-sensing cells in the central vasculature of turtles and to derive homologies with peripheral arterial chemoreceptors of other vertebrates. we used ... | 2015 | 25586499 |
| evaluation of plasma fibrinogen concentration as a diagnostic indicator of inflammation in red-eared sliders (trachemys scripta elegans). | to critically evaluate plasma fibrinogen concentration as a diagnostic indicator of inflammation in red-eared sliders (trachemys scripta elegans). | 2015 | 25554942 |
| complete mitochondrial genomes of the yellow-bellied slider turtle trachemys scripta scripta and anoxia tolerant red-eared slider trachemys scripta elegans. | the complete mitochondrial genomes of the yellow-bellied slider (trachemys scripta scripta) and anoxia tolerant red-eared slider (trachemys scripta elegans) turtles were sequenced to analyze gene arrangement. the complete mt genomes of t. s. scripta and elegans were circular molecules of 16,791 bp and 16,810 bp in length, respectively, and included an a + 1 frameshift insertion in nd3 and nd4l genes. the at content of the overall base composition of scripta and elegans was 61.2%. nucleotide sequ ... | 2016 | 25541313 |
| dense distributed processing in a hindlimb scratch motor network. | in reduced preparations, hindlimb movements can be generated by a minimal network of neurons in the limb innervating spinal segments. the network of neurons that generates real movements is less well delineated. in an ex vivo carapace-spinal cord preparation from adult turtles (trachemys scripta elegans), we show that ventral horn interneurons in mid-thoracic spinal segments are functionally integrated in the hindlimb scratch network. first, mid-thoracic interneurons receive intense synaptic inp ... | 2014 | 25100606 |
| evaluation of rebound tonometry in red-eared slider turtles (trachemys scripta elegans). | to evaluate feasibility and accuracy of intraocular pressure (iop) measurement by rebound tonometry in adult red-eared slider turtles and determine the effects of manual and chemical restraint on iop. | 2014 | 25097909 |
| honest sexual signaling in turtles: experimental evidence of a trade-off between immune response and coloration in red-eared sliders trachemys scripta elegans. | sexual signals can be evolutionarily stable if they are honest and condition dependent or costly to the signaler. one possible cost is the existence of a trade-off between maintaining the immune system and the elaboration of ornaments. this hypothesis has been experimentally tested in some groups of animals but not in others such as turtles. we experimentally challenged the immune system of female red-eared sliders trachemys scripta elegans, with a bacterial antigen (lipopolysaccharide (lps)) wi ... | 2014 | 25091549 |
| activation of the carbohydrate response element binding protein (chrebp) in response to anoxia in the turtle trachemys scripta elegans. | chrebp (carbohydrate response element binding protein) is a glucose-responsive transcription factor that is known to be an important regulator of glycolytic and lipogenic genes in response to glucose. we hypothesized that activation of chrebp could be relevant to anoxia survival by the anoxia-tolerant turtle, trachemys scripta elegans. | 2014 | 24931694 |
| a high-throughput protocol for message rna quantification using rna dot-blots. | this study develops a method to rapidly measure the relative abundance of mrna in total rna samples using a dot-blotting technique and biotin-labeled detection probes that recognize the polyadenylate tail on mrna. we demonstrate the effectiveness of this technique by determining the relative total amounts of mrna in three tissues of turtles (trachemys scripta elegans) exposed to normoxic versus anoxic conditions. the data emphasize the usefulness of the method for the simple and rapid analysis o ... | 2014 | 24560727 |
| golgi study of medium spiny neurons from dorsolateral striatum of the turtle trachemys scripta elegans. | comparative anatomy has shown similarities between reptilian and mammalian basal ganglia. here the morphological characteristics of the medium spiny neurons (msn) in the dorsolateral striatum (dls) of the turtle are described after staining them with the golgi technique. the soma of msn in dls showed three main forms: spherical, ovoid, and fusiform. the number of primary dendritic branches (3-4 dendrites/cell) was less than observed in mammals. the msn axon originates mainly from the soma, and r ... | 2013 | 24513300 |
| golgi study of medium spiny neurons from dorsolateral striatum of the turtle trachemys scripta elegans. | comparative anatomy has shown similarities between reptilian and mammalian basal ganglia. here the morphological characteristics of the medium spiny neurons (msn) in the dorsolateral striatum (dls) of the turtle are described after staining them with the golgi technique. the soma of msn in dls showed three main forms: spherical, ovoid, and fusiform. the number of primary dendritic branches (3-4 den-drites/cell) was less than observed in mammals. the msn axon originates mainly from the soma, and ... | 2013 | 24511608 |
| the efficacy of intracoelomic fospropofol in red-eared sliders (trachemys scripta elegans). | intravenous anesthetic delivery in reptiles can be challenging. current injectable techniques have varied induction/recovery times and anesthetic quality. this study hypothesized that intracoelomic administration of a new anesthetic, fospropofol, in turtles would result in dose-dependent anesthesia and respiratory depression. a two-part prospective trial using adult red-eared slider turtles (trachemys scripta elegans) weighing 764 +/- 17 g was conducted to determine an effective anesthetic dose ... | 2013 | 24450053 |
| genomic organization and identification of promoter regions for the bdnf gene in the pond turtle trachemys scripta elegans. | brain-derived neurotrophic factor (bdnf) is an important regulator of neuronal development and synaptic function. the bdnf gene undergoes significant activity-dependent regulation during learning. here, we identified the bdnf promoter regions, transcription start sites, and potential regulatory sequences for bdnf exons i-iii that may contribute to activity-dependent gene and protein expression in the pond turtle trachemys scripta elegans (tbdnf). by using transfection of bdnf promoter/luciferase ... | 2014 | 24443176 |
| radial glia in the proliferative ventricular zone of the embryonic and adult turtle, trachemys scripta elegans. | to better understand the role of radial glial (rg) cells in the evolution of the mammalian cerebral cortex, we investigated the role of rg cells in the dorsal cortex and dorsal ventricular ridge of the turtle, trachemys scripta elegans. unlike mammals, the glial architecture of adult reptile consists mainly of ependymoradial glia, which share features with mammalian rg cells, and which may contribute to neurogenesis that continues throughout the lifespan of the turtle. to evaluate the morphology ... | 2014 | 27504470 |
| morphological and mechanical changes in juvenile red-eared slider turtle (trachemys scripta elegans) shells during ontogeny. | turtles experience numerous modifications in the morphological, physiological, and mechanical characteristics of their shells through ontogeny. although a general picture is available of the nature of these modifications, few quantitative studies have been conducted on changes in turtle shell shape through ontogeny, and none on changes in strength or rigidity. this study investigates the morphological and mechanical changes that juvenile trachemys scripta elegans undergo as they increase in size ... | 2014 | 24301373 |
| prevalence of selected pathogens in western pond turtles and sympatric introduced red-eared sliders in california, usa. | pathogen introduction by invasive species has been speculated to be a cause of declining western pond turtle emys marmorata populations in california, usa. this study determined the prevalence of ranavirus spp., herpesvirus spp., mycoplasma spp. (via polymerase chain reaction of blood and nasal flush contents), and salmonella spp. infection (via fecal culture) in native e. marmorata and invasive red-eared sliders trachemys scripta elegans and compared infection prevalence in e. marmorata populat ... | 2013 | 24270022 |
| effects of body position and extension of the neck and extremities on lung volume measured via computed tomography in red-eared slider turtles (trachemys scripta elegans). | to determine the effects of body position and extension of the neck and extremities on ct measurements of ventilated lung volume in red-eared slider turtles (trachemys scripta elegans). | 2013 | 24094268 |
| prevalence of antibiotic-resistant gram-negative bacteria associated with the red-eared slider (trachemys scripta elegans). | free-ranging red-eared sliders (trachemys scripta elegans) were captured from farm ponds located in the flint hills of kansas and a zoo pond in emporia, kansas, usa, to evaluate their enteric bacterial flora and associated antibiotic resistance. bacteria obtained from cloacal swabs were composed of six different gram-negative genera. although antibiotic resistance was present in turtles captured from both locations, 40 and 49% of bacteria demonstrated multiple antibiotic resistance to four of th ... | 2013 | 24063095 |
| characterization of fructose-1,6-bisphosphate aldolase during anoxia in the tolerant turtle, trachemys scripta elegans: an assessment of enzyme activity, expression and structure. | one of the most adaptive facultative anaerobes among vertebrates is the freshwater turtle, trachemys scripta elegans. upon a decrease in oxygen supply and oxidative phosphorylation, these turtles are able to reduce their metabolic rate and recruit anaerobic glycolysis to meet newly established atp demands. within the glycolytic pathway, aldolase enzymes cleave fructose-1,6-bisphosphate to triose phosphates facilitating an increase in anaerobic production of atp. importantly, this enzyme exists p ... | 2013 | 23874782 |
| anoxia-responsive regulation of the foxo transcription factors in freshwater turtles, trachemys scripta elegans. | the forkhead class o (foxo) transcription factors are important regulators of multiple aspects of cellular metabolism. we hypothesized that activation of these transcription factors could play crucial roles in low oxygen survival in the anoxia-tolerant turtle, trachemys scripta elegans. | 2013 | 23850471 |
| identification of a functionally distinct truncated bdnf mrna splice variant and protein in trachemys scripta elegans. | brain-derived neurotrophic factor (bdnf) has a diverse functional role and complex pattern of gene expression. alternative splicing of mrna transcripts leads to further diversity of mrnas and protein isoforms. here, we describe the regulation of bdnf mrna transcripts in an in vitro model of eyeblink classical conditioning and a unique transcript that forms a functionally distinct truncated bdnf protein isoform. nine different mrna transcripts from the bdnf gene of the pond turtle trachemys scrip ... | 2013 | 23825634 |
| pharmacodynamics of alfaxalone after single-dose intramuscular administration in red-eared sliders (trachemys scripta elegans): a comparison of two different doses at two different ambient temperatures. | this study compares the pharmacodynamics of two different doses of alfaxalone administered intramuscularly (im) to red-eared sliders at two ambient temperatures. | 2013 | 23815147 |
| role of the trochlear nerve in eye abduction and frontal vision of the red-eared slider turtle (trachemys scripta elegans). | horizontal head rotation evokes significant responses from trochlear motoneurons of turtle that suggests they have a functional role in abduction of the eyes like that in frontal-eyed mammals. the finding is unexpected given that the turtle is generally considered lateral-eyed and assumed to have eye movements instead like that of lateral-eyed mammals, in which innervation of the superior oblique muscle by the trochlear nerve (niv) produces intorsion, elevation, and adduction (not abduction). us ... | 2013 | 23681972 |
| correlation between heavy metals and turtle abundance in ponds near the paducah gaseous diffusion plant, kentucky, usa. | reptiles are declining globally, and environmental contamination has been suggested as a contributing factor; however, few studies have investigated the relationship between contamination and reptile populations. we performed a mark-recapture study at ponds near the paducah gaseous diffusion plant (pgdp), kentucky, to determine if heavy metals had an impact on turtle populations. we measured concentrations of cadmium, chromium, copper, lead, and mercury in red-eared slider turtle (trachemys scri ... | 2013 | 23644581 |
| absence of post-lesion reactive gliosis in elasmobranchs and turtles and its bearing on the evolution of astroglia. | in the mature mammalian and avian central nervous systems, neuronal destructions are followed by reactive gliosis, but data on other vertebrates are rather controversial. mammals and birds belong to different amniote groups (synapsida and diapsida, respectively), but exhibit common general features in their glial architecture, mainly the predominance of astrocytes. two vertebrate groups seem to be in special positions of glial evolution: turtles (testudiniformes) and skates and rays (batoidea). ... | 2013 | 23640845 |
| purification and properties of white muscle lactate dehydrogenase from the anoxia-tolerant turtle, the red-eared slider, trachemys scripta elegans. | lactate dehydrogenase (ldh; e.c. 1.1.1.27) is a crucial enzyme involved in energy metabolism in muscle, facilitating the production of atp via glycolysis during oxygen deprivation by recycling nad(+). the present study investigated purified ldh from the muscle of 20 h anoxic and normoxic t. s. elegans, and ldh from anoxic muscle showed a significantly lower (47%) k m for l-lactate and a higher v max value than the normoxic form. several lines of evidence indicated that ldh was converted to a low ... | 2013 | 23533717 |
| increased activity of pre-motor network does not change the excitability of motoneurons during protracted scratch initiation. | intrinsic response properties of neurons change during network activity. these changes may reinforce the initiation of particular forms of network activity. if so, the involvement of neurons in particular behaviours in multifunctional networks could be determined by up- or down-regulation of their intrinsic excitability. here we employed an experimental paradigm of protracted scratch initiation in the integrated carapace-spinal cord preparation of adult turtles (chrysemys scripta elegans). the p ... | 2013 | 23339173 |
| ten polymorphic microsatellite loci developed from the red-eared slider (trachemys scripta elegans). | | 2012 | 23257297 |
| activation of the unfolded protein response during anoxia exposure in the turtle trachemys scripta elegans. | red-eared slider turtles, trachemys scripta elegans, can survive for several weeks without oxygen when submerged in cold water. we hypothesized that anaerobiosis is aided by adaptive up-regulation of the unfolded protein response (upr), a stress-responsive pathway that is activated by accumulation of unfolded proteins in the endoplasmic reticulum (er) and functions to restore er homeostasis. rt-pcr, western immunoblotting and dna-binding assays were used to quantify the responses and/or activati ... | 2013 | 23124854 |
| regulation of p53 by reversible post-transcriptional and post-translational mechanisms in liver and skeletal muscle of an anoxia tolerant turtle, trachemys scripta elegans. | the red-eared slider turtle (trachemys scripta elegans) exhibits well-developed natural anoxia tolerance that depends on multiple biochemical adaptations, including anoxia-induced hypometabolism. we hypothesized that signaling by the p53 protein could aid in establishing the hypometabolic state by arresting the cell cycle, protecting against dna damage as well as altering pathways of energy metabolism. immunoblotting was used to evaluate the regulation and post-transcriptional modifications of p ... | 2013 | 23124036 |
| antinociceptive efficacy of buprenorphine and hydromorphone in red-eared slider turtles (trachemys scripta elegans). | despite the frequent clinical use of buprenorphine in reptiles, its antinociceptive efficacy is not known. in a randomized, complete cross-over study, the antinociceptive efficacy of buprenorphine (0.2 mg/kg s.c.) was compared with hydromorphone (0.5 mg/kg s.c.), and saline (0.9% s.c. equivalent volume) in 11 healthy red-eared slider turtles (trachemys scripta elegans). additionally, buprenorphine at 0.1 and 1 mg/kg was compared with saline in six turtles. hindlimb withdrawal latencies were meas ... | 2012 | 23082538 |
| extensive diversification of igd-, igy-, and truncated igy(δfc)-encoding genes in the red-eared turtle (trachemys scripta elegans). | igy(δfc), containing only ch1 and ch2 domains, is expressed in the serum of some birds and reptiles, such as ducks and turtles. the duck igy(δfc) is produced by the same υ gene that expresses the intact igy form (ch1-4) using different transcriptional termination sites. in this study, we show that intact igy and igy(δfc) are encoded by distinct genes in the red-eared turtle (trachemys scripta elegans). at least eight igy and five igy(δfc) transcripts were found in a single turtle. together with ... | 2012 | 22972932 |
| regulation of liver lactate dehydrogenase by reversible phosphorylation in response to anoxia in a freshwater turtle. | lactate dehydrogenase (ldh) is the terminal enzyme of anaerobic glycolysis and key to hypoxia/anoxia survival by most animals. in this study, the effects of anoxic submergence (20 h at 7°c in nitrogen-bubbled water) were assessed on ldh from liver of an anoxia-tolerant freshwater turtle, the red-eared slider (trachemys scripta elegans). liver ldh from aerobic and anoxic turtles was purified to homogeneity in two steps. the kinetic properties and thermal stability of purified ldh were analyzed, r ... | 2012 | 22735190 |
| intramuscular administration of alfaxalone in red-eared sliders (trachemys scripta elegans)--effects of dose and body temperature. | to characterise the effects of alfaxalone by intramuscular (i.m.) injection in red-eared slider turtles and the influence of body temperature on anaesthetic duration and depth. | 2013 | 22726306 |
| evidence for cell cycle suppression and microrna regulation of cyclin d1 during anoxia exposure in turtles. | the red-eared slider turtle (trachemys scripta elegans) has a well-developed natural tolerance for oxygen deprivation that derives from biochemical adaptations, including anoxia-induced suppression of metabolic rate. we hypothesized that mechanisms that suppress atp-expensive cell cycle activity would contribute significantly to establishing the hypometabolic state during anaerobiosis. cyclin d1 is a critical regulator of the g 1 phase of the cell cycle and is regarded as key to initiating cell ... | 2012 | 22510561 |
| two-stage ampa receptor trafficking in classical conditioning and selective role for glutamate receptor subunit 4 (tglua4) flop splice variant. | previously, we proposed a two-stage model for an in vitro neural correlate of eyeblink classical conditioning involving the initial synaptic incorporation of glutamate receptor a1 (glua1)-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid type receptors (ampars) followed by delivery of glua4-containing ampars that support acquisition of conditioned responses. to test specific elements of our model for conditioning, selective knockdown of glua4 ampar subunits was used using small-int ... | 2012 | 22490558 |
| specialization for underwater hearing by the tympanic middle ear of the turtle, trachemys scripta elegans. | turtles, like other amphibious animals, face a trade-off between terrestrial and aquatic hearing. we used laser vibrometry and auditory brainstem responses to measure their sensitivity to vibration stimuli and to airborne versus underwater sound. turtles are most sensitive to sound underwater, and their sensitivity depends on the large middle ear, which has a compliant tympanic disc attached to the columella. behind the disc, the middle ear is a large air-filled cavity with a volume of approxima ... | 2012 | 22438494 |
| accumulation of polychlorinated biphenyls (pcbs) and evaluation of hematological and immunological effects of pcb exposure on turtles. | concentrations of total polychlorinated biphenyls (pcbs), aroclor 1260, and 26 congeners were measured in liver, fat, and eggs of red-eared slider turtles (trachemys scripta elegans) collected from ponds near or on the paducah gaseous diffusion plant (pgdp), kentucky, usa. concentrations of total pcbs (wet mass) ranged from 0.002 to 0.480 mg/kg, 0.028 to 0.839 mg/kg, and 0.001 to 0.011 mg/kg in liver, fat, and eggs, respectively. concentrations of arochlor 1260 did not exceed 0.430, 0.419, and 0 ... | 2012 | 22430883 |
| acute and persistent effects of pre- and posthatching thermal environments on growth and metabolism in the red-eared slider turtle, trachemys scripta elegans. | many ectotherms possess the capacity to survive a wide range of thermal conditions. long-term exposure to temperature can induce acclimational and/or organizational effects, and the developmental stage at which temperature exposure occurs may affect the type, degree, and persistence of these effects. we incubated red-eared slider turtle embryos at three different constant temperatures (t(inc); 26.5, 28.5, 30.5°c), then divided the resulting hatchlings between two water temperatures (t(water); 25 ... | 2012 | 22311775 |
| diagnosis and management of oviductal disease in three red-eared slider turtles (trachemys scripta elegans). | three mature, female, red-eared slider turtles (trachemys scripta elegans) were individually, and separately, diagnosed with different forms of oviductal disease. case 1 presented with acute cloacal bleeding and was diagnosed with acute oviductal rupture and ectopic eggs in the coelom. case 2 presented for repeated scratching in the direction of the cloaca and was diagnosed with chronic oviductal impaction and coelomitis. both cases were treated successfully by endoscopy-assisted complete ovario ... | 2012 | 22243411 |
| does müller cell differentiation occur prior to the emergence of synapses in embryonic turtle retina? | müller cells are the main glial cells in the retina, and are related to plexiform layer activity. recent studies have demonstrated that müller cells are involved in the synaptic conservation, plasticity, development and metabolism of glutamate. during turtle retinal development, layers, cells and synapses appear at different times. the aim of this research is to study the emergence of müller cells during embryonic development and their relationship with the synaptogenesis. the authors used retin ... | 2012 | 24660044 |
| helminth fauna of a turtle species introduced in japan, the red-eared slider turtle (trachemys scripta elegans). | the red-eared slider turtle (trachemys scripta elegans) was intentionally introduced from the united states to japan as a pet in the 1950s and has become established throughout much of the country. we examined red-eared slider turtles from two localities in japan for foreign parasitic helminths. consequently, a total of seven species of helminths were found: two monogeneans (neopolystoma exhamatum and polystomoides japonicum), three digeneans (spirorchisartericola, spi.elegans and telorchis clem ... | 2012 | 22047816 |
| information analysis of posterior canal afferents in the turtle, trachemys scripta elegans. | we have used sinusoidal and band-limited gaussian noise stimuli along with information measures to characterize the linear and non-linear responses of morpho-physiologically identified posterior canal (pc) afferents and to examine the relationship between mutual information rate and other physiological parameters. our major findings are: 1) spike generation in most pc afferents is effectively a stochastic renewal process, and spontaneous discharges are fully characterized by their first order st ... | 2012 | 21890114 |
| cadmium toxicokinetics and bioaccumulation in turtles: trophic exposure of trachemys scripta elegans. | ecotoxicological data in reptiles are mainly represented by field studies reporting the tissue burden of wild-captured individuals but much less is known regarding the processes of uptake, depuration, accumulation and the effects of inorganic contaminants in these species. in the present study, the accumulation, the path and the effects of exposure to cadmium (cd) through diet intake were investigated in female red eared slider turtles, trachemys scripta elegans. in the first phase of the experi ... | 2012 | 21814846 |
| metal accumulation and evaluation of effects in a freshwater turtle. | a variety of contaminants have been detected in aquatic and terrestrial environments around the paducah gaseous diffusion plant (pgdp), kentucky. the presence of these contaminants at the pgdp may pose a risk to biota, yet little is known about the bioaccumulation of contaminants and associated effects in wildlife, especially in aquatic turtles. the current study was initiated to evaluate: (1) the accumulation of heavy metals (cd, cr, cu, pb, and hg) in aquatic ecosystems associated with the pgd ... | 2011 | 21688058 |
| stereological estimate of the total number of neurons in spinal segment d9 of the red-eared turtle. | the red-eared turtle is an important animal model for investigating the neural activity in the spinal circuit that generates motor behavior. however, basic anatomical features, including the number of neurons in the spinal segments involved, are unknown. in the present study, we estimate the total number of neurons in segment d9 of the spinal cord in the red-eared turtle (trachemys scripta elegans) using stereological cell counting methods. in transverse spinal cord sections stained with modifie ... | 2011 | 21325510 |
| biomechanics of hair cell kinocilia: experimental measurement of kinocilium shaft stiffness and base rotational stiffness with euler-bernoulli and timoshenko beam analysis. | vestibular hair cell bundles in the inner ear contain a single kinocilium composed of a 9+2 microtubule structure. kinocilia play a crucial role in transmitting movement of the overlying mass, otoconial membrane or cupula to the mechanotransducing portion of the hair cell bundle. little is known regarding the mechanical deformation properties of the kinocilium. using a force-deflection technique, we measured two important mechanical properties of kinocilia in the utricle of a turtle, trachemys ( ... | 2011 | 21307074 |
| fast estimation of motion from selected populations of retinal ganglion cells. | we explore how the reconstruction efficiency of fast spike population codes varies with population size, population composition and code complexity. our study is based on experiments with moving light patterns which are projected onto the isolated retina of a turtle pseudemys scripta elegans. the stimulus features to reconstruct are sequences of velocities kept constant throughout segments of 500 ms. the reconstruction is based on the spikes of a retinal ganglion cell (rgc) population recorded e ... | 2011 | 21287355 |
| pancreatitis associated with the helminth serpinema microcephalus (nematoda: camallanidae) in exotic red-eared slider turtles (trachemys scripta elegans). | pancreatitis associated with the helminth serpinema microcephalus was found in three of 19 free-ranging red-eared slider turtles (trachemys scripta elegans) captured between march 2003 and september 2004 in southern spain. microscopic changes were associated with parasite migrations and were characterized by central areas of necrosis surrounded by leukocytes and resulted in destruction of exocrine tissue. the blood profile of one of the three female turtles revealed eosinophilia and hyperglycemi ... | 2011 | 21270009 |
| spectral sensitivity of the photointrinsic iris in the red-eared slider turtle (trachemys scripta elegans). | our goal in this study was to examine the red-eared slider turtle for a photomechanical response (pmr) and define its spectral sensitivity. pupils of enucleated eyes constricted to light by ∼11%, which was one-third the response measured in alert behaving turtles at ∼33%. rates of constriction in enucleated eyes that were measured by time constants (1.44-3.70 min) were similar to those measured in turtles at 1.97 min. dilation recovery rates during dark adaptation for enucleated eyes were predic ... | 2011 | 20951155 |
| perspectives in cell cycle regulation: lessons from an anoxic vertebrate. | the ability of an animal, normally dependent on aerobic respiration, to suspend breathing and enter an anoxic state for long term survival is clearly a fascinating feat, and has been the focus of numerous biochemical studies. when anoxia tolerant turtles are faced with periods of oxygen deprivation, numerous physiological and biochemical alterations take place in order to facilitate vital reductions in atp consumption. such strategies include reversible post-translational modifications as well a ... | 2009 | 20514219 |
| epigenetics in anoxia tolerance: a role for histone deacetylases. | the importance of epigenetics has been established in many key biological processes but the relevance of this regulatory mechanism to animal survival of low oxygen conditions has never been examined. to establish whether epigenetic mechanisms could be involved in natural anoxia tolerance, we have examined the anoxia-responsive expression of the transcriptional silencers, histone deacetylases (hdacs), in tissues of a unique model for anoxia tolerance, the freshwater turtle trachemys scripta elega ... | 2010 | 20437082 |
| comparison of gastrografin to barium sulfate as a gastrointestinal contrast agent in red-eared slider turtles (trachemys scripta elegans). | red-eared slider turtles (trachemys scripta elegans) commonly develop intestinal obstruction. the gastrointestinal transit time in turtles tends to be longer than in other animals, making a rapid diagnosis of obstruction difficult. fifteen red-eared sliders were given either gastrografin or 30% w/v barium sulfate orally to compare ease of administration, transit time, and image quality. each contrast medium was easy to administer but barium sulfate had to be administered more slowly (mean = 40s) ... | 2016 | 20166392 |
| first description of papillary carcinoma in the thyroid gland of a red-eared slider (trachemys scripta elegans ). | postmortem examination of the carcass of an approximately 10-year-old male red-eared slider ( trachemys scripta elegans ) was performed. the thyroid gland was enlarged, showed follicular structure, and shifted the base of the heart caudally. histology revealed differently shaped and sized follicles in the thyroid gland. based on the macroscopic appearance and histopathological changes of the thyroid gland, the pathological process was established as a papillary-cystic carcinoma. neoplasia of the ... | 2010 | 20159740 |
| dopaminergic modulation of spiny neurons in the turtle striatum. | intracellular recordings were obtained from brain slice preparation in neurons of the striatum of the turtle trachemys scripta elegans, analogous to the mammalian striatum in its topographic organization, synaptic connectivity, cytoarchitecture, and neurochemistry. here we show that these similarities extend to the electrophysiological properties of its neurons. biocytin staining revealed that 85% of the recorded neurons were medium spiny neurons while 15% were aspiny neurons. spiny neurons of t ... | 2010 | 20140492 |
| consensual pupillary light response in the red-eared slider turtle (trachemys scripta elegans). | purpose of this study was to determine if the turtle has a consensual pupillary light response (cplr), and if so, to compare it to its direct pupillary light response (dplr). one eye was illuminated with different intensities of light over a four log range while keeping the other eye in darkness. in the eye directly illuminated, pupil diameter was reduced by as much as approximately 31%. in the eye not stimulated by light, pupil diameter was also reduced but less to approximately 11%. when compa ... | 2010 | 20079368 |
| regulation of sarcoendoplasmic reticulum ca2+-atpase (serca) in turtle muscle and liver during acute exposure to anoxia. | the freshwater turtle trachemys scripta elegans naturally tolerates extended periods of anoxia during winter hibernation at the bottom of ice-locked ponds. survival in this anoxic state is facilitated by a profound depression of metabolic rate. as calcium levels are known to be elevated in anoxic turtles, and ion pumping is an atp-expensive process, we proposed that activity of the sarcoendoplasmic reticulum ca(2+)-atpase (serca) would be reduced in muscle and liver of t. s. elegans during acute ... | 2010 | 20008357 |
| haemangioma in the oesophagus of a red-eared slider (trachemys scripta elegans). | a haemangioma developing in the wall of the oesophagus and protruding into its cavity is reported for the first time from a red-eared slider (trachemys scripta elegans). as the tumour mechanically hampered swallowing, the animal was unable to eat and consequently developed a poor condition. histopathology of the tumour revealed all characteristics of a haemangioma: the blood-filled blood-vessels having an irregular cross-section were lined with endothelial cells. claudin-5 immunohistochemical an ... | 2009 | 19897452 |
| molecular mechanisms of turtle anoxia tolerance: a role for nf-kappab. | the transcription factor nf-kappab has recently emerged as a central regulator of the vertebrate stress response, controlling hundreds of different effector genes. we hypothesized that this transcription factor would be activated during oxygen deprivation in the anoxia-tolerant freshwater turtle, trachemys scripta elegans. western immunoblotting was used to examine the relative expression levels of the phosphorylated nf-kappab inhibitor, ikappabalpha, under normoxic and anoxic conditions in turt ... | 2010 | 19857558 |
| daily and seasonal rhythms in the respiratory sensitivity of red-eared sliders (trachemys scripta elegans). | the purpose of the present study was to determine whether the daily and seasonal changes in ventilation and breathing pattern previously documented in red-eared sliders resulted solely from daily and seasonal oscillations in metabolism or also from changes in chemoreflex sensitivity. turtles were exposed to natural environmental conditions over a one year period. in each season, oxygen consumption, ventilation and breathing pattern were measured continuously for 24 h while turtles were breathing ... | 2009 | 19801438 |
| phosphorylation of translation factors in response to anoxia in turtles, trachemys scripta elegans: role of the amp-activated protein kinase and target of rapamycin signalling pathways. | long-term survival of oxygen deprivation by animals with well-developed anoxia tolerance depends on multiple biochemical adaptations including strong metabolic rate depression. we investigated whether the amp-activated protein kinase (ampk) could play a regulatory role in the suppression of protein synthesis that occurs when turtles experience anoxic conditions. ampk activity and the phosphorylation state of ribosomal translation factors were measured in liver, heart, red muscle and white muscle ... | 2009 | 19579060 |
| topography of purkinje cells and other calbindin-immunoreactive cells within adult and hatchling turtle cerebellum. | the turtle's cerebellum (cb) is an unfoliated sheet, so the topography of its entire cortex can be easily studied physiologically by optical recordings. however, unlike the mammalian cb, little is known about the topography of turtle purkinje cells (pcs). here, topography was examined using calbindin-d(28k) immunohistochemistry of adult and hatchling turtles (trachemys scripta elegans, 2.5-15 cm carapace length). each cb was flattened between two sylgard sheets and fixed in paraformaldehyde. sec ... | 2009 | 19548045 |
| pupil constriction evoked in vitro by stimulation of the oculomotor nerve in the turtle (trachemys scripta elegans). | the pond turtle (trachemys scripta elegans) exhibits a notably sluggish pupillary light reflex (plr), with pupil constriction developing over several minutes following light onset. in the present study, we examined the dynamics of the efferent branch of the reflex in vitro using preparations consisting of either the isolated head or the enucleated eye. stimulation of the oculomotor nerve (niii) using 100-hz current trains resulted in a maximal pupil constriction of 17.4% compared to 27.1% observ ... | 2014 | 19523265 |
| the chelonian spinal nerve ganglia are a conglomerate of the spinal nerve ganglia proper and the sympathetic ganglia. | a tyrosine hydroxylase-immunoreactive cell mass is found in the caudal portion of the dorsal nerve ganglion of the red-eared slider, trachemys scripta elegans. the ganglion appears as a flat oval structure in the horizontal plane, where the major axis runs latero-medially, and the minor axis rostro-caudally in the ventral view. a communicating branch to the sympathetic chain diverges from the top of each tubercle which lies on the caudo-lateral side of the ganglion. a tyrosine hydroxylase- immun ... | 2009 | 19468213 |
| circadian and circannual rhythms in the metabolism and ventilation of red-eared sliders (trachemys scripta elegans). | endogenous circadian and circannual rhythms may exist in the metabolism, ventilation, and breathing pattern of turtles that could further prolong dive times during daily and seasonal periods of reduced activity. to test this hypothesis, turtles were held under seasonal or constant environmental conditions over a 1-yr period, and in each season, v(o)(2) and respiratory variables were measured in all animals under both the prevailing seasonal conditions and the constant conditions for 24 h. endoge ... | 2010 | 19358691 |
| localization and regulation of a facilitative urea transporter in the kidney of the red-eared slider turtle (trachemys scripta elegans). | urea is the major excretory end product of nitrogen metabolism in most chelonian reptiles. in the present study, we report the isolation of a 1632 base pair cdna from turtle kidney with one open reading frame putatively encoding a 403-residue protein, the turtle urea transporter (turtle ut). the first cloned reptilian ut has high homology with uts (facilitated urea transporters) cloned from vertebrates, and most closely resembles the ut-a subfamily. injection of turtle ut crna into xenopus oocyt ... | 2009 | 19112144 |
| sympathetic influence on the pupillary light response in three red-eared slider turtles (trachemys scripta elegans). | we investigated the effects of phenylephrine and its combination with vecuronium bromide on the iris of turtles to determine if the pupillary light response is affected by sympathetic innervation. | 2013 | 19046290 |
| steroid signaling and temperature-dependent sex determination-reviewing the evidence for early action of estrogen during ovarian determination in turtles. | the developmental processes underlying gonadal differentiation are conserved across vertebrates, but the triggers initiating these trajectories are extremely variable. the red-eared slider turtle (trachemys scripta elegans) exhibits temperature-dependent sex determination (tsd), a system where incubation temperature during a temperature-sensitive period of development determines offspring sex. however, gonadal sex is sensitive to both temperature and hormones during this period-particularly estr ... | 2009 | 18992835 |
| protein kinase c-dependent and independent signaling pathways regulate synaptic glur1 and glur4 ampar subunits during in vitro classical conditioning. | protein kinase c (pkc) signal transduction pathways have been implicated in mechanisms of synaptic plasticity and learning, however, the roles of the different pkc family isoforms remain to be clarified. previous studies showed that nmdar-mediated trafficking of glur4-containing ampars supports conditioning and that the mitogen-activated protein kinases (mapks) have a central role in the synaptic delivery of glur4 subunits. here, an in vitro model of classical conditioning in pond turtles, pseud ... | 2008 | 18809472 |
| varying hydric conditions during incubation influence egg water exchange and hatchling phenotype in the red-eared slider turtle. | environmental conditions within the nest, notably temperature and moisture of substrate, exert a powerful influence during embryogenesis in oviparous reptiles. the influence of fluctuating nest temperatures has been experimentally examined in different reptile species; however, similar experiments using moisture as the key variable are lacking. in this article, we examine the effect of various substrate moisture regimes during incubation on different traits (egg mass, incubation length, and hatc ... | 2013 | 18419559 |
| steroid signaling system responds differently to temperature and hormone manipulation in the red-eared slider turtle (trachemys scripta elegans), a reptile with temperature-dependent sex determination. | many reptiles, including the red-eared slider turtle (trachemys scripta elegans), exhibit temperature-dependent sex determination (tsd). temperature determines gonadal sex during the middle of embryogenesis, or the temperature-sensitive period (tsp), when gonadal sex is labile to both temperature and hormones--particularly estrogen. the biological actions of steroid hormones are mediated by their receptors as defined here as the classic transcriptional regulation of target genes. to elucidate es ... | 2007 | 18391529 |
| dendritic properties of turtle pyramidal neurons. | the six-layered mammalian neocortex evolved from the three-layered paleocortex, which is retained in present-day reptiles such as the turtle. thus the turtle offers an opportunity to examine which cellular and circuit properties are fundamental to cortical function. we characterized the dendritic properties of pyramidal neurons in different cortical regions of mature turtles, pseudemys scripta elegans, using whole cell recordings and calcium imaging from the axon, soma, and dendrites in a slice ... | 2008 | 18045998 |
| adrenal-kidney-gonad complex measurements may not predict gonad-specific changes in gene expression patterns during temperature-dependent sex determination in the red-eared slider turtle (trachemys scripta elegans). | many turtles, including the red-eared slider turtle (trachemys scripta elegans) have temperature-dependent sex determination in which gonadal sex is determined by temperature during the middle third of incubation. the gonad develops as part of a heterogenous tissue complex that comprises the developing adrenal, kidney, and gonad (akg complex). owing to the difficulty in excising the gonad from the adjacent tissues, the akg complex is often used as tissue source in assays examining gene expressio ... | 2007 | 17592622 |
| gonadal expression of sf1 and aromatase during sex determination in the red-eared slider turtle (trachemys scripta), a reptile with temperature-dependent sex determination. | many egg-laying reptiles have temperature-dependent sex determination (tsd), where the offspring sex is determined by incubation temperature during a temperature-sensitive period (tsp) in the middle third of development. the underlying mechanism transducing a temperature cue into an ovary or testis is unknown, but it is known that steroid hormones play an important role. during the tsp, exogenous application of estrogen can override a temperature cue and produce females, while blocking the activ ... | 2007 | 17490415 |
| distribution and characteristics of endogenous digestive enzymes in the red-eared slider turtle, trachemys scripta elegans. | distribution and properties of the main digestive enzymes including protease and amylase, from stomach, pancreas and the anterior, middle and posterior intestine of the adult red-eared slider turtle trachemys scripta elegans were studied at various phs and temperatures. the optimum temperature and ph for protease in stomach, pancreas and the anterior, middle and posterior intestine were 40 degrees c, 2.5; 50 degrees c, 8.0; 50 degrees c, 7.0; 50 degrees c, 8.0; and 50 degrees c, 8.5; respectivel ... | 2007 | 17462929 |
| pharmacokinetics of metronidazole in the red-eared slider turtle (trachemys scripta elegans) after single intracoelomic injection. | | 2007 | 17348904 |
| parasympathetic control of the pupillary light response in the red-eared slider turtle (pseudemys scripta elegans). | we investigated effects of both vecuronium bromide, a nicotinic cholinergic antagonist, and atropine, a muscarinic cholinergic antagonist, on the pupil of the turtle to determine whether responses to light are controlled by parasympathetic innervations acting on the iris. | 2013 | 17324166 |
| immunohistochemical and hodological characterization of calbindin-d28k-containing neurons in the spinal cord of the turtle, pseudemys scripta elegans. | neurons and fibers containing the calcium-binding protein calbindin-d28k (cb) were studied by immunohistochemical techniques in the spinal cord of adult and juvenile turtles, pseudemys scripta elegans. abundant cell bodies and fibers immunoreactive for cb were widely and distinctly distributed throughout the spinal cord. most neurons and fibers were labeled in the superficial dorsal horn, but numerous cells were also located in the intermediate gray and ventral horn. in the dorsal horn, most cb- ... | 2007 | 17203484 |
| effects of ultraviolet radiation on 25-hydroxyvitamin d3 synthesis in red-eared slider turtles (trachemys scripta elegans). | to determine whether there are increased concentrations of 25-hydroxyvitaminn d(3) in red-eared slider turtles (trachemys scripta elegans) after exposure to uv radiation. | 2006 | 17144809 |
| toxicity of glyphosate as glypro and li700 to red-eared slider (trachemys scripta elegans) embryos and early hatchlings. | more than 8.2 billion ha of cropland, gardens, and forests are treated with the herbicide glyphosate each year. whereas the toxicity of glyphosate and associated adjuvants has been measured in other vertebrates, few, if any, studies have looked at their effects in reptiles. in some instances, management of turtle habitat requires control of successional stages through application of herbicides. adults and juvenile turtles may be exposed directly, whereas embryos may contact the chemicals through ... | 2006 | 17022419 |
| benign ovarian teratoma in a red-eared slider turtle (trachemys scripta elegans). | | 2006 | 16861392 |
| housing density and growth in juvenile red-eared turtles. | growth rates in juvenile turtles relate strongly to their health and welfare, both in the wild and in captivity. newly hatched turtles in the wild are subject to such high levels of predation that, in some cases, as few as i % survive their first year of life. juvenile turtles in captivity succumb more quickly to the effects of poor housing conditions and poor diets than do older adults. in both the wild and in captivity, turtles who grow quickly during their first year of life stand a better ch ... | 1999 | 16363952 |
| metal accumulation in eggs of the red-eared slider (trachemys scripta elegans) in the lower illinois river. | the illinois river is a highly utilized navigable waterway in the us midwest, and has historically been contaminated with metal toxicants from various industrial and municipal pollution sources. little information on metal contamination is available in the lower illinois river, and in particular, in the habitat of the red-eared slider (trachemys scripta elegans) at the southern end of the river near grafton, il. this study was conducted to determine current levels of metal contamination in water ... | 2006 | 16216308 |
| purification and properties of the glutathione s-transferases from the anoxia-tolerant turtle, trachemys scripta elegans. | glutathione s-transferases (gsts) play critical roles in detoxification, response to oxidative stress, regeneration of s-thiolated proteins, and catalysis of reactions in nondetoxification metabolic pathways. liver gsts were purified from the anoxia-tolerant turtle, trachemys scripta elegans. purification separated a homodimeric (subunit relative molecular mass =34 kda) and a heterodimeric (subunit relative molecular mass = 32.6 and 36.8 kda) form of gst. the enzymes were purified 23-69-fold and ... | 2005 | 16008560 |
| thalamocortical connections in the pond turtle pseudemys scripta elegans. | thalamocortical connections are a neuroanatomical feature shared among vertebrates, although the extent and organization of these connections vary among species. from an evolutionary standpoint, reptiles represent early stages of the pattern of connectivity between the thalamus and cortex, and elucidation of these pathways may help to reveal the biological significance of these projections. the present tract tracing study was performed to examine the organization of thalamocortical projections i ... | 2005 | 15761219 |
| distribution of facial motor neurons in the pond turtle pseudemys scripta elegans. | a tract tracing study was performed to examine the localization of the facial nucleus in the brain stem of the pond turtle, pseudemys scripta elegans. neurobiotin and the fluorescent tracers alexa fluor 488 and 594 were used to retrogradely label neurons of the abducens or facial nerves. the results showed that the facial nucleus has two subnuclei, a medial group and a lateral group. measurements of cell size revealed no significant differences between these populations. double labeling studies ... | 2005 | 15567568 |
| neuronal control of turtle hindlimb motor rhythms. | the turtle, trachemys scripta elegans, uses its hindlimb during the rhythmic motor behaviors of walking, swimming, and scratching. for some tasks, one or more motor strategies or forms may be produced, e.g., forward swimming or backpaddling. this review discusses experiments that reveal characteristics of the spinal neuronal networks producing these motor behaviors. limb-movement studies show shared properties such as rhythmic alternation between hip flexion and hip extension, as well as variabl ... | 2005 | 15452660 |
| structural determination and histochemical localization of ghrelin in the red-eared slider turtle, trachemys scripta elegans. | we purified ghrelin peptide and determined the cdna sequence encoding the precursor protein from the stomach of the red-eared slider turtle, trachemys scripta elegans. the trachemys ghrelin is comprised of 25-amino acids and has the sequence gssflspeyqntqqrkdpkkhtkln. the third serine residue was modified by n-octanoic (c8:0), decanoic (c10:0) or unsaturated decanoic acid (c10:1). the carboxyl-terminal end of the peptide was not amidated, as seen in the ghrelins of other land vertebrates. quanti ... | 2004 | 15242751 |
| morphology of the turtle accessory optic system. | neural signals of the moving visual world are detected by a subclass of retinal ganglion cells that project to the accessory optic system in the vertebrate brainstem. we studied the dendritic morphologies and direction tuning of these brainstem neurons in turtle (pseudemys scripta elegans) to understand their role in visual processing. full-field checkerboard patterns were drifted on the contralateral retina while whole-cell recordings were made in the basal optic nucleus in an intact brainstem ... | 2016 | 15088717 |
| resistance to disuse atrophy in a turtle hindlimb muscle. | the purpose of this study was to characterize the changes in a turtle hindlimb muscle (external gastrocnemius) after exposure to three conditions of disuse: immobilization, tenotomy, and spinalization. histochemical analysis and measurement of muscle fiber cross-sectional area and weighted cross-sectional area were used to assess the potential conversion of muscle fiber types and changes in fiber size. it was found that unlike its counterpart in mammalian endotherms, the external gastrocnemius m ... | 2004 | 14968256 |
| effects of fatigue on the catchlike property in a turtle hindlimb muscle. | the purpose of this report was to test for the possibility that a catchlike, force-enhancing property, attributable to a particular stimulation pattern, could be evoked in non-mammalian turtle muscle, just as it has been shown in mammalian muscle. we tested for the presence of this property in dynamic lengthening and shortening contractions, as well as in the more commonly studied isometric contractions. a second aim was to note the effects of fatigue on the catchlike property, if the latter was ... | 2003 | 14566421 |
| connectivity of the turtle accessory optic system. | recent whole-cell recordings show that there are multiple synaptic inputs to the accessory optic system of the pond turtle pseudemys scripta elegans (the basal optic nucleus, bon), suggesting a complex role in visual processing. the bon outputs have now been investigated using transport of dii, rhodamine-conjugated and biotinylated dextrans. although transport was primarily anterograde, contralateral retinal ganglion cells were labeled retrogradely, confirming that the injection site was a retin ... | 2003 | 14519514 |
| malignant ovarian teratoma in a red-eared slider (trachemys scripta elegans). | a 7-year-old intact female red-eared slider (trachemys scripta elegans) presented with anorexia of 2-3-weeks duration. coelomic radiographs demonstrated 3 shelled eggs in the right cavity. hormone therapy failed to induce oviposition. exploratory laparotomy revealed 3 calcified eggs in the right oviduct and a large mass obliterating the left ovary. the large, multilobulate mass had scattered, firm, white nodules and weighed 450 g. histopathology revealed a malignant teratoma composed of immature ... | 2003 | 12580303 |
| hormone levels in yolk decline throughout development in the red-eared slider turtle (trachemys scripta elegans). | this study investigates the potential effects of maternally derived hormones present in the yolk of reptile eggs. specifically, we ask when are these hormones utilized by developing red-eared slider turtles (trachemys scripta elegans), a species with temperature-dependent sex determination (tsd). eggs were incubated at 27 degrees c, a male-producing temperature, and at 31 degrees c, a female-producing temperature. concentrations of progesterone, testosterone, and 17beta-estradiol were measured a ... | 2002 | 12460601 |
| turtle sex determination assay: mass balance and responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3,3',4,4',5-pentachlorobiphenyl. | polyhalogenated hydrocarbons have been implicated in the anomalous sexual differentiation of mammals and reptiles. here, a temperature-sensitive turtle sex determination assay using the red-eared slider (trachemys scripta elegans) was used to determine the estrogenic or antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd) and 3,3',4,4',5-pentachlorobiphenyl (pcb-126). neither tcdd nor pcb-126 showed a statistically significant difference in the resulting sex ratios (fisher's exa ... | 2002 | 12389929 |
| dacryops in a red-eared slider (chrysemys scripta elegans): case report. | clinical and histologic findings of an orbital lacrimal cyst (dacryops) in a 23-year-old-female red-eared slider (chrysemys scripta elegans) are described. main ophthalmologic findings included unilateral exophthalmus, engorged episcleral vessels, periocular swelling superior to the globe, incomplete lid closure, and reduced ocular motility. based on sonographic and cytologic examination of the tissue, the preliminary diagnosis of an orbital cyst was established. after surgical resection of the ... | 2002 | 12236878 |
| experimental manipulation of steroid concentrations in circulation and in egg yolks of turtles. | steroid hormones in egg yolks are increasingly recognized as an important component of maternal and offspring fitness in oviparous vertebrates. yet, except for in birds, the mechanism by which females allocate these resources is poorly understood. we manipulated systemic levels of hormones in reproductively mature female red-eared slider turtles (trachemys scripta elegans) with silastic implants to test the hypothesis that hormones are allocated to developing follicles as a quantitative function ... | 2002 | 12115919 |
| photoreceptors and visual pigments in the red-eared turtle, trachemys scripta elegans. | absorbance spectra of cone outer segments and oil droplets were recorded microspectrophotometrically in the retina of the red-eared turtle, trachemys scripta elegans. there are four cone visual pigments, with lambda(max) = 617 nm (red sensitive), 515 nm (green sensitive), 458 nm (blue sensitive), and 372 nm (uv-sensitive). the red-sensitive pigment resides in single cones with red or orange oil droplets, and in both members of double cones. the principal member of the double cone contains an ora ... | 2008 | 11925010 |
| high-speed vsd imaging of visually evoked cortical waves: decomposition into intra- and intercortical wave motions. | in the pond turtle, pseudemys scripta elegans, visually evoked cortical waves propagate at different velocities within the primary visual area compared with waves that pass into the secondary visual area. in an effort to separate intra- and intercortical wave motions, movies of visually evoked cortical waves recorded by high-speed voltage-sensitive dye (vsd) imaging were subjected to karhunen-loéve (kl) decomposition. this procedure decomposes the vsd movies into a series of basis images that ca ... | 2002 | 11877522 |