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Aaron B Stoler, Brent M Walker, William D Hintz, Devin K Jones, Lovisa Lind, Brian M Mattes, Matthew S Schuler, Rick A Relyea
As the number of chemical contaminants in freshwater ecosystems increase, it is important to understand whether contaminants interact in ecologically important ways. We investigated the independent and interactive effects two contaminants that frequently co-occur in freshwater environments among higher latitudes, including a commonly applied insecticide (carbaryl) and road salt (NaCl). We hypothesized that the addition of either contaminant would result in a decline of zooplankton, an algal bloom, and the subsequent decline of both periphyton and periphyton consumers...
October 24, 2016: Environmental Toxicology and Chemistry
Laurence D Picton, Keith T Sillar
Dopamine plays important roles in the development and modulation of motor control circuits. Here we show that dopamine exerts potent effects on the central pattern generator circuit controlling locomotory swimming in post-embryonic Xenopus tadpoles. Dopamine (0.5-100 μM) reduced fictive swim bout occurrence and caused both spontaneous and evoked episodes to become shorter, slower and weaker. The D2-like receptor agonist quinpirole mimicked this repertoire of inhibitory effects on swimming, whilst the D4 receptor antagonist, L745,870, had the opposite effects...
October 20, 2016: Scientific Reports
Jeffrey P Stephens, Aaron B Stoler, Jason P Sckrabulis, Aaron J Fetzer, Keith A Berven, Scott D Tiegs, Thomas R Raffel
According to ecological stoichiometry (ES), the growth of a consumer with abundant resources should increase as body and resource stoichiometry become more similar. However, for organisms with complex life cycles involving distinct changes in biology, nutrient demands might change in response to ontogenetic changes in body stoichiometry. Tadpole growth and development has been found to be largely nitrogen (N) limited, as predicted for organisms developing N-rich tissues like muscle. However, tadpole metamorphosis includes periods of rapid development of phosphorus (P)-rich bones in preparation for a terrestrial lifestyle...
October 17, 2016: Oecologia
Amir Nourhani, Stephen J Ebbens, John G Gibbs, Paul E Lammert
Translationally diffusive behavior arising from the combination of orientational diffusion and powered motion at microscopic scales is a known phenomenon, but the peculiarities of the evolution of expected position conditioned on initial position and orientation have been neglected. A theory is given of the spiral motion of the mean trajectory depending upon propulsion speed, angular velocity, orientational diffusion, and rate of random chirality reversal. We demonstrate the experimental accessibility of this effect using both tadpole-like and Janus sphere dimer rotating motors...
September 2016: Physical Review. E
Thomas Naert, Robin Colpaert, Tom Van Nieuwenhuysen, Dionysia Dimitrakopoulou, Jannick Leoen, Jurgen Haustraete, Annekatrien Boel, Wouter Steyaert, Trees Lepez, Dieter Deforce, Andy Willaert, David Creytens, Kris Vleminckx
Retinoblastoma is a pediatric eye tumor in which bi-allelic inactivation of the Retinoblastoma 1 (RB1) gene is the initiating genetic lesion. Although recently curative rates of retinoblastoma have increased, there are at this time no molecular targeted therapies available. This is, in part, due to the lack of highly penetrant and rapid retinoblastoma animal models that facilitate rapid identification of targets that allow therapeutic intervention. Different mouse models are available, all based on genetic deactivation of both Rb1 and Retinoblastoma-like 1 (Rbl1), and each showing different kinetics of retinoblastoma development...
October 14, 2016: Scientific Reports
Jeffrey R Row, Michael E Donaldson, Jessica N Longhi, Barry J Saville, Dennis L Murray
A potential cause of amphibian population declines are the impacts of environmental degradation on tadpole development. We conducted RNA sequencing on developing northern leopard frog tadpoles and through de novo transcriptome assembly we annotated a large number of open reading frames comparable in number and extent to genes identified in Xenopus. Using our transcriptome, we found transcript level changes between early (Gosner 26-31) and late (Gosner 36-41) stage tadpoles were the greatest in the tail, which is reabsorbed throughout development...
October 11, 2016: Genomics
Juanmei Gao, Hangze Ruan, Xianjie Qi, Yi Tao, Xia Guo, Wanhua Shen
Radial glial cells (RGs) are one of the important progenitor cells that can differentiate into neurons or glia to form functional neural circuits in the developing central nervous system (CNS). Histone deacetylases (HDACs) has been associated with visual activity dependent changes in BrdU-positive progenitor cells in the developing brain. We previously have shown that HDAC1 is involved in the experience-dependent proliferation of RGs. However, it is less clear whether two other members of class I HDACs, HDAC2 and HDAC3, are involved in the regulation of radial glia proliferation...
2016: Frontiers in Cellular Neuroscience
Seiji Tanaka, Ken-Ichi Harano, Yudai Nishide, Ryohei Sugahara
Schistocerca gregaria exhibits density-dependent body color polyphenism. Nymphs occurring at low population densities show green-brown polyphenism. They show phase polyphenism and develop black patterns at high population densities. Recent studies suggest a third type of polyphensim, that is, homochromy, a response to background color. Laboratory experiments that considered homochromy suggest that humidity is not directly involved in green-brown polyphenism and that odor from other individuals does not induce black patterns...
October 2016: Current Opinion in Insect Science
Freya E Rowland, Madelyn B Rawlings, Raymond D Semlitsch
Primary production can be controlled through bottom-up (e.g., resources) or top-down (e.g., predators) constraints. Two key bottom-up resources in small aquatic systems are light and nutrients, and forest canopy cover heavily influences these factors, whereas amphibian and invertebrate colonizers exert top-down pressure as grazers and predators. We designed our experiment to specifically manipulate two different top-down and bottom-up factors. We manipulated resources by altering light (low/high) and nutrient (low/high) availability; omnivores with the presence/absence of southern leopard frog tadpoles (Lithobates sphenocephalus); and predators with the presence/absence of spotted salamander larvae (Ambystoma maculatum) in a full-factorial experiment conducted over 14 weeks...
October 7, 2016: Oecologia
April L Bagwill, Matthew B Lovern, Thomas A Worthington, Loren M Smith, Scott T McMurry
Amphibian metamorphosis is complex and larval morphology and physiology are completely restructured during this time. Amphibians that live in unpredictable environments are often exposed to stressors that can directly and indirectly alter physiological systems during development, with subsequent consequences (carryover effects) later in life. In this study, we investigated the effects of water level reduction on development rate, spleen size and cellularity, and examined the role of corticosterone levels in premetamorphic, metamorphic, and postmetamorphic New Mexico spadefoot toads (Spea multiplicata)...
October 6, 2016: Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology
Li Zhang, Yubin Huang, Bing Hu
Granule cells, rich in dendrites with densely punctated dendritic spines, are the most abundant inhibitory interneurons in the olfactory bulb. The dendritic spines of granule cells undergo remodeling during the development of the nervous system. The morphological plasticity of the spines' response to different olfactory experiences in vivo is not fully known. In initial studies, a single granule cell in Xenopus tadpoles was labeled with GFP plasmids via cell electroporation; then, morphologic changes of the granule cell spines were visualized by in vivo confocal time-lapse imaging...
October 7, 2016: Scientific Reports
Alberto Valero-Gracia, Rita Marino, Fabio Crocetta, Valeria Nittoli, Stefano Tiozzo, Paolo Sordino
BACKGROUND: Thaliaceans is one of the understudied classes of the phylum Tunicata. In particular, their phylogenetic relationships remain an issue of debate. The overall pattern of serotonin (5-HT) distribution is an excellent biochemical trait to interpret internal relationships at order level. In the experiments reported here we compared serotonin-like immunoreactivity at different life cycle stages of two salpid, one doliolid, and one pyrosomatid species. This multi-species comparison provides new neuroanatomical data for better resolving the phylogeny of the class Thaliacea...
2016: Frontiers in Zoology
Christopher K Thompson, Hollis T Cline
: Thyroid hormone (TH) regulates many cellular events underlying perinatal brain development in vertebrates. Whether and how TH regulates brain development when neural circuits are first forming is less clear. Furthermore, although the molecular mechanisms that impose spatiotemporal constraints on TH action in the brain have been described, the effects of local TH signaling are poorly understood. We determined the effects of manipulating TH signaling on development of the optic tectum in stage 46-49 Xenopus laevis tadpoles...
October 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Nobuya Murakami, Takato Morioka, Satoshi O Suzuki, Nobutaka Mukae, Kimiaki Hashiguchi, Koji Iihara
BACKGROUND: Parietal atretic cephalocele (AC) and its associated intracranial venous anomalies, such as vertical embryonic positioning of the straight sinus (VEP of SS), have, in previous reports, been exclusively restricted to the midline. CLINICAL PRESENTATION: We report a patient with lateralized parietal AC on the right side. The AC was in the shape of a tadpole, with a large head and a long tail, extending to the proximity of the right external canthus, where a lacrimal gland fistula was observed...
October 4, 2016: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
David C Blackburn, Christian Boix, Eli Greenbaum, Marissa Fabrezi, Danny Meirte, Andrew J Plumptre, Edward L Stanley
The species diversity of the frog genus Cardioglossa (family Arthroleptidae) is concentrated in the Lower Guinean Forest Zone of Central Africa with most of the 19 species occurring in Cameroon and neighboring countries (Amiet 1972a,b; Blackburn 2008; Hirschfeld et al. 2015). These small leaf-litter frogs are typically found in primary or secondary forest, have shrill whistling calls, are characterized by a variety of color patterns, and lay terrestrial eggs that hatch and develop into elongate, stream-adapted tadpoles (Amiet 1972a,b, 1973; Rödel et al...
September 23, 2016: Zootaxa
Sairi Miyata, Tomotaka Yada, Natsuko Ishikawa, Kazi Taheruzzaman, Ryohei Hara, Takashi Matsuzaki, Akio Nishikawa
To understand the mechanism of muscle remodeling during Xenopus laevis metamorphosis, we examined the in vitro effect of insulin-like growth factor 1 (IGF-1) on growth and differentiation of three different-fate myogenic cell populations: tadpole tail, tadpole dorsal, and young adult leg muscle. IGF-1 promoted growth and differentiation of both tail and leg myogenic cells only under conditions where these cells could proliferate. Inhibition of cell proliferation by DNA synthesis inhibitor cytosine arabinoside completely canceled the IGF-1's cell differentiation promotion, suggesting the possibility that IGF-1's differentiation-promotion effect is an indirect effect via IGF-1's cell proliferation promotion...
October 3, 2016: In Vitro Cellular & Developmental Biology. Animal
Lisa E Kelly, Reyna I Martinez-De Luna, Heithem M El-Hodiri
The Retinal homeobox (rax) gene is expressed in vertebrate retinal progenitor and stem cells and is essential for retinal development. In frogs, rax is expressed in the ciliary marginal zone (CMZ), a region containing retinal progenitor and stem cells at the anterior of the eye. Little is known regarding regulation of rax transcription and regulation of transcription of rax targets. We found that three ultra-conserved genomic elements (UCEs) flanking the rax coding region regulate expression of a rax promoter-GFP transgene in Xenopus tadpoles...
October 3, 2016: Genesis: the Journal of Genetics and Development
Olívia G S Araújo, Célio F B Haddad, Hélio R DA Silva, Lourdes A Pugener
Pipa is a Neotropical genus of frogs that dwell in freshwater environments. It includes four species that lack free-swimming larvae (P. aspera, P. arrabali, P. pipa, and P. snethlageae) and three with tadpoles (P. carvalhoi, P. myersi, and P. parva). Developmental tables such as the one proposed by Nieuwkoop and Faber might be useful for Pipa species with tadpoles. However, for the other Pipa species, to determine stages by this table or by any of the tables already prepared for frogs without tadpoles (e.g...
September 22, 2016: Anais da Academia Brasileira de Ciências
Akira Oike, Maho Kodama, Yoriko Nakamura, Masahisa Nakamura
Androgens play a critical role in testicular differentiation in many species of vertebrates. While female-to-male sex reversal can be induced by testosterone (T) in some species of amphibians, the mechanism still remains largely unknown even at the histological level. In this study, we determined a threshold dosage of T to induce female-to-male sex reversal in the Japanese frog Rana (R.) rugosa. Tadpoles were allowed to metamorphose into frogs with T present in the rearing water. At 0.2 ng/mL T, female frogs formed tissue comprising a mixture of ovary and testis, the so-called ovotestis, the size of which was significantly smaller than the wild-type ovary...
September 28, 2016: Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology
Jennifer L Bosse, Heithem M El-Hodiri
The insulinoma-associated 1 (insm1) gene is involved in the differentiation of several neuronal and endoderm derived cell types. insm1 is expressed in the retina and brain of several vertebrates including Xenopus laevis. We report the detailed expression pattern of insm1 in the X. laevis tadpole retina and brain. X. laevis insm1 is expressed in most of the ciliary marginal zone of the mature retina and the optic tectum, dorsal pallium, hypothalamus and preoptic areas of the developing tadpole brain. Overall, insm1 is expressed in regions of the tadpole brain and retina harboring populations of progenitor cells...
September 23, 2016: Gene Expression Patterns: GEP
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