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https://www.readbyqxmd.com/read/29241134/effects-of-the-herbicides-linuron-and-s-metolachlor-on-perez-s-frog-embryos
#1
Carla Quintaneiro, Amadeu M V M Soares, Marta S Monteiro
Presence of pesticides in the environment and their possible effects on aquatic organisms are of great concern worldwide. The extensive use of herbicides in agricultural areas are one of the factors contributing to the known decline of amphibian populations. Thus, as non-target species, amphibians can be exposed in early life stages to herbicides in aquatic systems. In this context, this study aims to evaluate effects of increasing concentrations of two maize herbicides, linuron and S-metolachlor on embryos of the Perez' frog (Pelophylax perezi) during 192 h...
November 29, 2017: Chemosphere
https://www.readbyqxmd.com/read/29238549/rapid-extirpation-of-a-north-american-frog-coincides-with-an-increase-in-fungal-pathogen-prevalence-historical-analysis-and-implications-for-reintroduction
#2
Andrea J Adams, Allan P Pessier, Cheryl J Briggs
As extinctions continue across the globe, conservation biologists are turning to species reintroduction programs as one optimistic tool for addressing the biodiversity crisis. For repatriation to become a viable strategy, fundamental prerequisites include determining the causes of declines and assessing whether the causes persist in the environment. Invasive species-especially pathogens-are an increasingly significant factor contributing to biodiversity loss. We hypothesized that Batrachochytrium dendrobatidis (Bd), the causative agent of the deadly amphibian disease chytridiomycosis, was important in the rapid (<10 years) localized extirpation of a North American frog (Rana boylii) and that Bd remains widespread among extant amphibians in the region of extirpation...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29238521/limited-polymorphism-of-the-functional-mhc-class-ii-b-gene-in-the-black-spotted-frog-pelophylax-nigromaculatus-identified-by-locus-specific-genotyping
#3
Hong-Yi Liu, Fei Xue, Jie Gong, Qiu-Hong Wan, Sheng-Guo Fang
Amphibians can be more vulnerable to environmental changes and diseases than other species because of their complex life cycle and physiological requirements. Therefore, understanding the adaptation of amphibians to environmental changes is crucial for their conservation. Major histocompatibility complex (MHC) presents an excellent tool for the investigation of adaptive variations and the assessment of adaptive potential because it can be under strong diversifying selection. Here, we isolated the MHC class II B (MHCIIB) gene from cDNA sequences of the black-spotted frog (Pelophylax nigromaculatus), a widespread amphibian species in China, and designed locus-specific primers to characterize adaptive variability of this amphibian...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29236056/the-potential-of-frog-skin-derived-peptides-for-development-into-therapeutically-valuable-immunomodulatory-agents
#4
REVIEW
Jelena M Pantic, Ivan P Jovanovic, Gordana D Radosavljevic, Nebojsa N Arsenijevic, J Michael Conlon, Miodrag L Lukic
The aim of this article is to review the immunoregulatory actions of frog skin-derived peptides in order to assess their potential as candidates for immunomodulatory or anti-inflammatory therapy. Frog skin peptides with demonstrable immunomodulatory properties have been isolated from skin secretions of a range of species belonging to the families Alytidae, Ascaphidae, Discoglossidae, Leptodactylidae, Pipidae and Ranidae. Their effects upon production of inflammatory and immunoregulatory cytokines by target cells have been evaluated ex vivo and effects upon cytokine expression and immune cell activity have been studied in vivo by flow cytometry after injection into mice...
December 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29235249/anticancer-effects-of-resveratrol-in-canine-hemangiosarcoma-cell-lines
#5
A Carlson, K S Alderete, M K O Grant, D M Seelig, L C Sharkey, B N M Zordoky
Hemangiosarcoma (HSA) is a highly malignant tumour with aggressive biological behaviour. HSAs are more common in dogs than other domestic animals. The median survival time of dogs with HSA remains short, even with chemotherapy and surgery. Therefore, there is a critical need to improve the adjuvant chemotherapeutic regimens to improve clinical outcomes in dogs with HSA. Resveratrol has been shown to possess strong anti-proliferative and/or pro-apoptotic properties in human cancer cell lines. Nevertheless, the potential anticancer effects of resveratrol have not been reported in canine HSAs...
December 13, 2017: Veterinary and Comparative Oncology
https://www.readbyqxmd.com/read/29228191/frogs-find-rapidly-otus-with-galaxy-solution
#6
Frédéric Escudié, Lucas Auer, Maria Bernard, Mahendra Mariadassou, Laurent Cauquil, Katia Vidal, Sarah Maman, Guillermina Hernandez-Raquet, Sylvie Combes, Géraldine Pascal
Motivation: Metagenomics leads to major advances in microbial ecology and biologists need user friendly tools to analyze their data on their own. Results: This Galaxy-supported pipeline, called FROGS, is designed to analyze large sets of amplicon sequences and produce abundance tables of Operational Taxonomic Units (OTUs) and their taxonomic affiliation. The clustering uses Swarm. The chimera removal uses VSEARCH, combined with original cross-sample validation. The taxonomic affiliation returns an innovative multi-affiliation output to highlight databases conflicts and uncertainties...
December 7, 2017: Bioinformatics
https://www.readbyqxmd.com/read/29226803/quantitative-missense-variant-effect-prediction-using-large-scale-mutagenesis-data
#7
Vanessa E Gray, Ronald J Hause, Jens Luebeck, Jay Shendure, Douglas M Fowler
Large datasets describing the quantitative effects of mutations on protein function are becoming increasingly available. Here, we leverage these datasets to develop Envision, which predicts the magnitude of a missense variant's molecular effect. Envision combines 21,026 variant effect measurements from nine large-scale experimental mutagenesis datasets, a hitherto untapped training resource, with a supervised, stochastic gradient boosting learning algorithm. Envision outperforms other missense variant effect predictors both on large-scale mutagenesis data and on an independent test dataset comprising 2,312 TP53 variants whose effects were measured using a low-throughput approach...
December 1, 2017: Cell Systems
https://www.readbyqxmd.com/read/29225405/sometimes-noise-is-beneficial-stream-noise-informs-vocal-communication-in-the-little-torrent-frog-amolops-torrentis
#8
Longhui Zhao, Bicheng Zhu, Jichao Wang, Steven E Brauth, Yezhong Tang, Jianguo Cui
Many kinds of environmental noise can interfere with acoustic communication and efficient decision making in terrestrial species. Here we identified an exception to this generalization in a streamside species, the little torrent frog (Amolops torrentis) which communicates in a stream noise environment. To determine whether stream noise can act as a cue regarding the microhabitat characteristics of senders, we performed phonotaxis experiments using stimulus pairs constructed with synthetic male calls (high or low dominant frequency) and stream noise with varied signal-to-noise ratios...
2017: Journal of Ethology
https://www.readbyqxmd.com/read/29225186/hinokitiol-inhibits-compound-action-potentials-in-the-frog-sciatic-nerve
#9
Nobuya Magori, Tsugumi Fujita, Eiichi Kumamoto
Hinokitiol (β-thujaplicin) is a natural tropolone derivative contained in Chamaecyparis taiwanensis that has various actions including anti-inflammatory activities. Various plant-derived compounds inhibit compound action potentials (CAPs) in a manner dependent on the chemical structure of the compounds; however, the effects of hinokitiol on nerve conduction have not been examined. To determine whether hinokitiol inhibits CAPs and, if so, the chemical structure of hinokitiol that is important in this inhibition, we examined the effects of hinokitiol and its related compounds on fast-conducting CAPs using the frog sciatic nerve and the air-gap method...
December 7, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/29223282/the-hypothalamic-pituitary-thyroid-axis-and-biological-rhythms-the-discovery-of-tsh-s-unexpected-role-using-animal-models
#10
REVIEW
Keisuke Ikegami, Takashi Yoshimura
Thyroid hormones (TH) are important for development, growth, and metabolism. It is also clear that the synthesis and secretion of TH are regulated by the hypothalamic-pituitary-thyroid (HPT) axis. Animal models have helped advance our understanding of the roles and regulatory mechanisms of TH. The animals' bodies develop through coordinated timing of cell division and differentiation. Studies of frog metamorphosis led to the discovery of TH and their role in development. However, to adapt to rhythmic environmental changes, animals also developed various endocrine rhythms...
October 2017: Best Practice & Research. Clinical Endocrinology & Metabolism
https://www.readbyqxmd.com/read/29222721/are-the-adverse-effects-of-stressors-on-amphibians-mediated-by-their-effects-on-stress-hormones
#11
Caitlin R Gabor, Sarah A Knutie, Elizabeth A Roznik, Jason R Rohr
Adverse effects of anthropogenic changes on biodiversity might be mediated by their impacts on the stress response of organisms. To test this hypothesis, we crossed exposure to metyrapone, a synthesis inhibitor of the stress hormone corticosterone, with exposure to the herbicide atrazine and the fungal pathogen Batrachochytrium dendrobatidis (Bd) to assess whether the effects of these stressors on tadpoles and post-metamorphic frogs were mediated by corticosterone. Metyrapone countered atrazine- and Bd-induced corticosterone elevations...
December 8, 2017: Oecologia
https://www.readbyqxmd.com/read/29219046/molecular-cloning-and-functional-characterization-of-antimicrobial-peptides-brevinin-1ulf-and-ulmin-1ula-in-the-skin-of-the-newly-classified-ryukyu-brown-frog-rana-ulma
#12
Daisuke Ogawa, Maki Mochitate, Maho Furukawa, Itaru Hasunuma, Tetsuya Kobayashi, Sakae Kikuyama, Shawichi Iwamuro
Antimicrobial peptides (AMPs) were previously isolated from the skin of the Ryukyu brown frog Rana okinavana. However, this species has recently been reclassified as two species, i.e., Rana kobai and Rana ulma. As a result, it was determined that AMPs isolated from R. okinavana were in fact products of R. kobai, but not of R. ulma. In the present study, we collected skin samples from the species R. ulma and cloned twelve cDNAs encoding AMP precursors for the acyclic brevinin-1ULa--1ULf, the temporin-ULa-ULc, ranatuerin-2ULa, japonicin-1ULa, and a novel peptide using reverse-transcription polymerase chain reaction techniques...
December 2017: Zoological Science
https://www.readbyqxmd.com/read/29218516/glut-characterization-using-frog-xenopus-laevis-oocytes
#13
Wentong Long, Debbie O'Neill, Chris I Cheeseman
Xenopus laevis oocytes are a useful heterologous expression system for expressing glucose transporters (GLUTs) and examining their functions. In this chapter, we provide a detailed protocol on oocyte extraction and preparation for GLUT9 protein expression. Furthermore, we describe the determination of GLUT9 overexpression level by biotinylation and Western blotting analysis. Finally, we also describe how GLUT9-expressing oocytes can be used to measure urate kinetics by radioisotopes as well as two-microelectrode voltage clamping techniques...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29218002/xenopus-laevis-as-a-model-organism-for-the-study-of-spinal-cord-formation-development-function-and-regeneration
#14
REVIEW
Laura N Borodinsky
The spinal cord is the first central nervous system structure to develop during vertebrate embryogenesis, underscoring its importance to the organism. Because of its early formation, accessibility to the developing spinal cord in amniotes is challenging, often invasive and the experimental approaches amenable to model systems like mammals are limited. In contrast, amphibians, in general and the African-clawed frog Xenopus laevis, in particular, offer model systems in which the formation of the spinal cord, the differentiation of spinal neurons and glia and the establishment of spinal neuron and neuromuscular synapses can be easily investigated with minimal perturbations to the whole organism...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/29217629/map-like-navigation-from-distances-exceeding-routine-movements-in-the-three-striped-poison-frog-ameerega-trivittata
#15
Andrius Pašukonis, Matthias-Claudio Loretto, Walter Hödl
Most animals move in dense habitats where distant landmarks are limited, but how they find their way around remains poorly understood. Poison frogs inhabit the rainforest understory where they shuttle tadpoles from small territories to widespread pools. Recent studies revealed their excellent spatial memory and the ability to home back from several hundred meters. It remains unclear if this homing ability is restricted to the areas that had been previously explored or if it allows the frogs to navigate from areas outside their direct experience...
December 7, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/29216539/influence-of-extracellular-environment-on-the-motility-and-structural-properties-of-spermatozoa-collected-from-hormonally-stimulated-panamanian-golden-frog-atelopus-zeteki
#16
Gina Della Togna, Brian Gratwicke, Matthew Evans, Lauren Augustine, Han Chia, Ed Bronikowski, James B Murphy, Pierre Comizzoli
A better understanding of the factors influencing the biology of amphibian spermatozoa after release from the testis is a prerequisite to the development of sperm preservation methods. The objective of the study was to determine the effect of extracellular conditions (exposure to water and different temperatures) over time on the sperm motility and structural properties (including morphology and DNA integrity) collected from hormonally stimulated Atelopus zeteki. Following intraperitoneal injection of gonadotropin-releasing hormone agonist (des-Gly10, D-Ala6, Pro-NHEt9 GnRH; 4 μg/g of body weight), human chorionic gonadotropin (hCG, 10 IU/gbw), or Amphiplex™ (0...
November 29, 2017: Theriogenology
https://www.readbyqxmd.com/read/29211619/life-on-the-edge-a-comparative-study-of-ecophysiological-adaptations-of-frogs-to-tropical-semiarid-environments
#17
Catalina Cruz-Piedrahita, Carlos A Navas, Andrew J Crawford
A key goal of ecology and evolution is to understand the relative contributions of environment and history in determining the geographic distribution of organisms. For the Neotropical lowlands, where temperatures are similar across landscapes, we hypothesize that water balance may be a critical but understudied factor in determining the distribution of species. Amphibians are especially sensitive to variation in precipitation due to their permeable skin. Here we focused on lowland frogs of northwestern South America and investigated variation among 17 species in potentially important ecologically relevant performance variables related to water balance, testing for possible adaptations to semiarid conditions within species...
January 2018: Physiological and Biochemical Zoology: PBZ
https://www.readbyqxmd.com/read/29210355/neuroangiostrongyliasis-the-subarachnoid-phase-and-its-implications-for-anthelminthic-therapy
#18
Paul Prociv, Megan Turner
Infection with the Rat Lungworm Angiostrongylus cantonensis is the leading cause of human eosinophilic meningoencephalitis worldwide. From its origins in southeastern Asia, the parasite was spread extensively throughout the twentieth century and is now established in many of the world's warmer regions. Its clinical effects range from mild and transient symptoms, usually headache with peripheral nerve dysfunction, to severe and permanent central nervous system (CNS) damage, occasionally fatal. The severity and prognosis of disease are determined by the larval dose, acquired by ingesting infected intermediate hosts (slugs and snails) or, less often, paratenic hosts, such as crabs, shrimps, frogs, and monitor lizards...
December 4, 2017: American Journal of Tropical Medicine and Hygiene
https://www.readbyqxmd.com/read/29210297/modern-morphological-methods-for-tadpole-studies-a-comparison-of-micro-ct-and-clearing-and-staining-protocols-modified-for-frog-larvae
#19
M Krings, H Müller, M J Heneka, D Rödder
Micro-computed tomography (micro-CT) scanning and three-dimensional reconstruction have revolutionized morphological studies. Whereas species descriptions and comparative studies formerly were based on external appearance and dissection, we now can visualize muscles, skeleton and viscera in intact animals. In most cases, visualization of internal structures depends on appropriate staining methods. Staining with iodine, phosphotungstic acid (PTA) and osmium tetroxide are established methods, but some problems remain...
December 6, 2017: Biotechnic & Histochemistry: Official Publication of the Biological Stain Commission
https://www.readbyqxmd.com/read/29210016/amphibiophilus-mooiensis-n-sp-nematoda-amphibiophilidae-a-parasite-of-amietia-delalandii-dum%C3%A3-ril-bibron-amphibia-pyxicephalidae-from-south-africa
#20
Roman Svitin, Louis Du Preez
Four species of the genus Amphibiophilus Skrjabin, 1916 from pyxycephalid frogs in southern and central Africa are currently recognised as valid. Several specimens of Amphibiophilus were found in material from the common river frog, Amietia delalandii (Duméril & Bibron) (Amphibia: Pyxicephalidae), collected in Potchefstroom (North-West Province, South Africa). These specimens clearly differ from all previously known species by the shape of the distal end of the spicule, the shape of the gubernaculum and the structure of the synlophe...
December 5, 2017: Systematic Parasitology
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