Read by QxMD icon Read


Marina Walker, Mariana L Lyra, Célio F B Haddad
The genus Fritziana (Anura: Hemiphractidae) comprises six described species (F. goeldii, F. ohausi, F. fissilis, F. ulei, F. tonimi, and F. izecksohni) that are endemic to the Brazilian Atlantic Forest. Although the genus has been the subject of studies dealing with its taxonomy, phylogeny, and systematics, there is considerable evidence for cryptic diversity hidden among the species. The present study aims to understand the genetic diversity and phylogenetic relationships among the species of Fritziana, as well as the relationships among populations within species...
February 13, 2018: Molecular Phylogenetics and Evolution
Karen M Kiemnec-Tyburczy, Karen E Tracy, Karen R Lips, Kelly R Zamudio
Major histocompatibility complex (MHC) genes encode proteins in the acquired immune response pathway that often show distinctive selection-driven patterns in wild vertebrate populations. We examined genetic variation and signatures of selection in the MHC class I alpha 1 (A1)- and alpha 2 (A2)-domain encoding exons of two frog congeners [Agalychnis callidryas (n = 20) and A. lemur (n = 20)] from a single locality in Panama. We also investigated how historical demographic processes may have impacted MHC genetic diversity by analyzing a neutral mitochondrial marker...
February 15, 2018: Genetica
Emily A Wilson, Cheryl J Briggs, Tom L Dudley
Amphibian species are experiencing population declines due to infection by the fungal pathogen, Batrachochytrium dendrobatidis (Bd). The African clawed frog (Xenopus laevis), an asymptomatic carrier of Bd, has been implicated in the spread of this pathogen through global trade and established invasive populations on several continents. However, research has not explored the relationships of both life stages of this amphibian with Bd. While the post-metamorphic individuals may act as a reservoir, spreading the infection to susceptible species, the filter-feeding larvae may consume the motile Bd zoospores from the water column, potentially reducing pathogen abundance and thus the likelihood of infection...
2018: PloS One
Ira L Blitz
The creation of mutant lines by genome editing is accelerating genetic analysis in many organisms. CRISPR/Cas9 methods have been adapted for use in the African clawed frog, Xenopus, a longstanding model organism for biomedical research. Traditional breeding schemes for creating homozygous mutant lines with CRISPR/Cas9-targeted mutagenesis have several time-consuming and laborious steps. To facilitate the creation of mutant embryos, particularly to overcome the obstacles associated with knocking out genes that are essential for embryogenesis, a new method called leapfrogging was developed...
February 1, 2018: Journal of Visualized Experiments: JoVE
Denis Abramochkin, Vladislav Kuzmin
The striking seasonal difference in sensitivity of frog cardiac muscle to acetylcholine or stimulation of parasympathetic nervous fibers has been noted almost a century ago, although its electrophysiological basis has never been revealed. The present study compares the effects of the muscarinic agonist carbamylcholine chloride (CCh 10-8-10-5 M) on electrical activity in isolated atrial and ventricular preparations from dormant frogs (Rana temporaria) caught in January (winter-acclimatized, WA) and from active frogs caught in July (summer-acclimatized, SA)...
February 10, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Douglas C Tozer, Owen Steele, Mark Gloutney
Wetlands conserved using water level manipulation, cattle exclusion, naturalization of uplands, and other techniques under the North American Waterfowl Management Plan ("conservation project wetlands") are important for ducks, geese, and swans ("waterfowl"). However, the assumption that conservation actions for waterfowl also benefit other wildlife is rarely quantified. We modeled detection and occupancy of species at sites within 42 conservation project wetlands compared to sites within 52 similar nearby unmanaged wetlands throughout southern Ontario, Canada, and small portions of the adjacent U...
February 8, 2018: Journal of Environmental Management
Kyle J Hovey, Emily M Seiter, Erin E Johnson, Ralph A Saporito
Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens...
February 10, 2018: Journal of Chemical Ecology
Lewis J Campbell, S Austin Hammond, Stephen J Price, Manmohan D Sharma, Trenton W J Garner, Inanc Birol, Caren C Helbing, Lena Wilfert, Amber G F Griffiths
Ranaviruses are responsible for a lethal, emerging infectious disease in amphibians and threaten their populations throughout the world. Despite this, little is known about how amphibian populations respond to ranaviral infection. In the United Kingdom, ranaviruses impact the common frog (Rana temporaria). Extensive public engagement in the study of ranaviruses in the UK has led to the formation of a unique system of field sites containing frog populations of known ranaviral disease history. Within this unique natural field system, we used RNA sequencing (RNA-Seq) to compare the gene expression profiles of R...
February 8, 2018: Molecular Ecology
Masayoshi Tokita, Yuya Hasegawa, Wataru Yano, Hiroshi Tsuji
The order Anura (frogs and toads) is a group of amphibians and contains over 6500 extant species living in a variety of environments. Each frog species evolved body form adaptive for living and breeding in their own habitats. In Japan, four taxa of Bufo are living: Western-Japanese common toad (Bufo japonicus japonicus), Eastern-Japanese common toad (B. japonicus formosus), Miyako toad (B. gargarizans miyakonis) and Japanese stream toad (B. torrenticola). The former three taxa breed in still water as many other species of Bufo do...
February 2018: Zoological Science
Xiuying Jia, Zhengquan Liu, Xiangjun Lu, Juan Tang, Yingzhu Wu, Qiongxia Du, Jianbo He, Xinyun Zhang, Jinxiao Jiang, Wenli Liu, Yuqing Zheng, Ying Ding, Weiqin Zhu, Hangjun Zhang
Microcystin-leucine-arginine (MCLR) is the most popular and toxic variant among microcystins, which can cause severe reproductive toxicity to animals. However, the mechanisms of reproductive toxicity induced by MCLR in amphibians are still not entirely clear. In the current study, toxicity mechanisms of MCLR on the reproductive system of male Rana nigromaculata followed by low concentration (0, 0.1, 1, and 10 μg/L) and short-term (0, 7, and 14 days) MCLR exposure were shown. It was observed that MCLR could be bioaccumulated in the testes of male frogs, and the theoretical bioaccumulation factor values were 0...
February 1, 2018: Environmental Pollution
Nikos Solounias, Melinda Danowitz, Elizabeth Stachtiaris, Abhilasha Khurana, Marwan Araim, Marc Sayegh, Jessica Natale
We revisit digit reduction in the horse and propose that all five digits are partially present in the modern adult forelimb. Osteological descriptions of selected tetradactyl, tridactyl and monodactyl equids demonstrate the evolution of the forelimb. Histological, osteological and palaeontological evidence suggest that the Equus distal forelimb is more complex than traditionally conceived. The current understanding is that the horse distal forelimb consists of one complete digit (III) and two reduced splint metacarpals (II and IV)...
January 2018: Royal Society Open Science
Ariadne F Sabbag, Mariana L Lyra, Kelly R Zamudio, Célio F B Haddad, Renato N Feio, Felipe S F Leite, João L Gasparini, Cinthia A Brasileiro
The Brazilian Atlantic coastal forest is one of the most heterogeneous morphoclimatic domains on earth and is thus an excellent region in which to examine the role that habitat heterogeneity plays in shaping diversification of lineages and species. Here we present a molecular phylogeny of the rock frogs of the genus Thoropa Cope, 1865, native to the Atlantic forest and extending to adjacent campo rupestre of Brazil. The goal of this study is to reconstruct the evolutionary history of the genus using multilocus molecular phylogenetic analyses...
February 1, 2018: Molecular Phylogenetics and Evolution
Stefanie Allgeier, Bianca Frombold, Valentin Mingo, Carsten A Brühl
Bacillus thuringiensis var. israelensis (Bti) is presumed to be an environmental friendly agent for the use in either health-related mosquito control or the reduction of nuisance associated with mosquitoes from seasonal wetlands. Amphibians inhabiting these valuable wetlands may be exposed to Bti products several times during their breeding season. Up until now, information regarding effects on the non-targeted group of amphibians has to be considered rather inconsistent. On this account, we evaluated how three repeated exposures to frequently used Bti formulations (VectoBac®12AS, VectoBac®WG) in field-relevant rates affect European common frog (Rana temporaria) larvae...
January 24, 2018: Environmental Research
Maho Kodama, Madoka Yoshida, Masami Endo, Tohru Kobayashi, Akira Oike, Shigeki Yasumasu, Masahisa Nakamura
Nanos is expressed in the primordial germ cells (PGCs) and also the germ cells of a variety of organisms as diverse as Drosophila, medaka fish, Xenopus and mouse. In Nanos3-deficient mice, PGCs fail to incorporate into the gonad and the size of the testis and ovary is thereby dramatically reduced. To elucidate the role of Nanos in an amphibian species, we cloned Nanos3 cDNA from the testis of the R. rugosa frog. RT-PCR analysis showed strong expression of Nanos3 mRNA in the testis of adult R. rugosa frogs, but expression was not sexually dimorphic during gonadal differentiation...
February 5, 2018: Development, Growth & Differentiation
Nancy E Karraker, Samantha Fischer, Anchalee Aowphol, Jennifer Sheridan, Sinlan Poo
Background: Lowland areas in tropical East and Southeast Asia have a long history of conversion from forestland to agricultural land, with many remaining forests being chronically degraded by wood cutting, livestock grazing, and burning. Wetland-breeding amphibians that have evolved in lowland forests in the region have adjusted to changes in habitat composition caused by humans' activities, and populations continue to persist. However, we have little understanding of the impacts of forest disturbance on these species beyond assessments of abundance and distribution, and species considered to be common and widespread have been largely neglected...
2018: PeerJ
Rana Jafari, Rick Trebino
We use an algorithmic technique called "multi-grid" to improve the speed of convergence of the cross-correlation frequency-resolved-optical-gating (XFROG) pulse-retrieval algorithm for very complex pulses. The multi-grid approach uses a smaller trace (N/4 × N/4) drawn from the original N × N trace for initial iterations, yielding poorer resolution and range, but proceeding ~16 times faster for such iterations. The pulse field rapidly retrieved from this smaller array then provides the initial guess for the larger, full array, significantly reducing the number of iterations required on the full array...
February 5, 2018: Optics Express
Sandeep Mannava, Andrew G Geeslin, Salvatore J Frangiamore, Mark E Cinque, Matthew G Geeslin, Jorge Chahla, Marc J Philippon
The use of hip arthroscopy to treat various forms of hip pathology continues to grow. As part of a standard evaluation for eligibility for hip arthroscopy, we routinely obtain standard radiographs to assess the hip joint. These include orthogonal projections of the acetabulum and proximal femur, which can be obtained with a standing false profile, supine anteroposterior pelvis, and a lateral view of the proximal femur (either Dunn 45° or 90°, frog-leg lateral, or cross-table lateral). A comprehensive analysis of the radiographs is of utmost importance in order to indicate a patient for hip arthroscopy, for preoperative planning, and to determine prognosis...
October 2017: Arthroscopy Techniques
Alexander T Baugh, Brandon Bastien, Meghan B Still, Nicole Stowell
Minimally invasive methods for estimating hormone concentrations in wild vertebrates offer the opportunity to repeatedly measure behavior and hormone concentrations within individuals while minimizing experimenter interference during sample collection. We examined three steroid hormones (corticosterone, CORT; 17-β estradiol, E2; progesterone, PROG) in túngara frogs (Physalaemus pustulosus) using non-invasive water-borne methods. Using solid-phase extraction of water samples and liquid extraction of plasma and homogenate samples, coupled with enzyme immunoassays, we complimented the conventional validation approaches (parallelism, recovery determination) with dose-response assays that incorporated pharmacological challenges with adrenocorticotropic hormone (ACTH) and human chorionic gonadotropin (HCG)...
February 1, 2018: General and Comparative Endocrinology
Nicolas Rodrigues, Tania Studer, Christophe Dufresnes, Nicolas Perrin
According to the canonical model of sex-chromosome evolution, the degeneration of Y or W chromosomes (as observed in mammals and birds respectively) results from an arrest of recombination in the heterogametic sex, driven by the fixation of sexually antagonistic mutations. However, sex chromosomes have remained homomorphic in many lineages of fishes, amphibians, and non-avian reptiles. According to the 'fountain-of-youth' model, this homomorphy results from occasional events of sex reversal. If recombination arrest in males is controlled by maleness per se (and not by genotype), then Y chromosomes are expected to recombine in XY females, preventing their long-term degeneration...
January 30, 2018: Molecular Biology and Evolution
Junhua Hu, Jianping Jiang
BACKGROUND: Identifying and understanding the mechanisms that shape barriers to dispersal and resulting biogeographic boundaries has been a longstanding, yet challenging, goal in ecology, evolution and biogeography. Characterized by stable, adjacent ranges, without any intervening physical barriers, and limited, if any, range overlap in a narrow contact zone, parapatric species are an interesting system for studying biogeographic boundaries. The geographic ranges of two parapatric frog species, Feirana quadranus and F...
February 2, 2018: BMC Ecology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"