Search results for "gon"
showing 10 items of 6445 documents
Data from: Temporal genetic structure in a poecilogonous polychaete: the interplay of developmental mode and environmental stochasticity
2015
Background: Temporal variation in the genetic structure of populations can be caused by multiple factors, including natural selection, stochastic environmental variation, migration, or genetic drift. In benthic marine species, the developmental mode of larvae may indicate a possibility for temporal genetic variation: species with dispersive planktonic larvae are expected to be more likely to show temporal genetic variation than species with benthic or brooded non-dispersive larvae, due to differences in larval mortality and dispersal ability. We examined temporal genetic structure in populations of Pygospio elegans, a poecilogonous polychaete with within-species variation in developmental m…
Data from: There is no general model for occlusal kinematics in conodonts
2015
Knowledge of conodont element function is based largely on analysis of morphologically similar P1 elements of few comparatively closely related species known from abundant articulated remains. From these, a stereotypical pattern of rotational occlusion has been inferred, leading to the suggestion that this may represent a general model for ozarkodinin P1 elements at the very least. We test the generality of this occlusal model through functional analysis of Pseudofurnishius murcianus P1 elements which, though superficially similar to homologous elements in gnathodids, evolved their platform morphology independently, through a different mode of morphogenesis, and in a different topological p…
Data from: Seasonal genetic variation associated with population dynamics of a poecilogonous polychaete worm
2018
Poecilogonous species show variation in developmental mode, with larvae that differ both morphologically and ecologically. The spionid polychaete Pygospio elegans shows variation in developmental mode not only between populations, but also seasonally within populations. We investigated the consequences of this developmental polymorphism on the spatial and seasonal genetic structure of P. elegans at four sites in the Danish Isefjord-Roskilde-Fjord estuary at six time points, from March 2014 until February 2015. We found genetic differentiation between our sampling sites as well as seasonal differentiation at two of the sites. The seasonal genetic shift correlated with the appearance of new s…
Data from: Negative frequency-dependent selection of sexually antagonistic alleles in Myodes glareolus
2011
Sexually antagonistic genetic variation, where optimal values of traits are sex-dependent, is known to slow the loss of genetic variance associated with directional selection on fitness-related traits. However, sexual antagonism alone is not sufficient to maintain variation indefinitely. Selection of rare forms within the sexes can help to conserve genotypic diversity. We combined theoretical models and a field experiment with Myodes glareolus to show that negative frequency-dependent selection on male dominance maintains variation in sexually antagonistic alleles. In our experiment, high-dominance male bank voles were found to have low-fecundity sisters, and vice versa. These results show …
Data from: Testis asymmetry in birds: the influences of sexual and natural selection
2014
Gonad size and shape asymmetries are particularly common in birds. Although some obvious size and shape differences between the left and right testes in birds were first documented more than a century ago, little is known about what influences the variation across species in either the degree or the direction of these asymmetries. Here we show that a left bias in size is the most likely ancestral state in most orders and families, and that there is a weak but significant negative relation between the degree of size and shape asymmetries. In extant species, testis size and shape symmetries increase with the degree of sperm competition (relative testes mass), but those relations are significa…
Some observations on the spectrophotometric determination of nitrite using ergonovine-p-dimethylaminobenzaldehyde
1991
Abstract The system ergonovine maleate-p-diethylaminobenzaldehyde in sulfuric acid media is applied to the kinetic-spectrophotometric determination of nitrite ions with competitive precision. The reaction rate is strongly enhanced by the presence of nitrite or ferric ions, being the nitrite in the “promoting” role of the reaction. Linear calibration plots are obtained for nitrite concentration ranges 0.3–2.4 ppm or 0.66–6 ppb. The influence of foreign compounds is also established.
Entering the Nano-Cosmos of the Cell by Means of Spatial Position Determination Microscopy (SPDM): Implications for Medical Diagnostics and Radiation…
2013
During the last 20 years fluorescence light microscopy has made an enormous progress towards fluorescence nanoscopy in order to elucidate the nanostructural organization of cellular machineries beyond classical limits of resolution in light microscopy. One of these novel techniques is Spatial Position Determination Microscopy (SPDM), an approach of molecular localization microscopy based on the application of specific fluorescence labelling of cellular structures by means of dyes that undergo reversible photobleaching resulting in blinking effects during image acquisition. This blinking allows spectral separation of individual molecules and thus precise localization and distances measuremen…
5‐Alpha reductase inhibitors in androgenetic alopecia: Shifting paradigms, current concepts, comparative efficacy, and safety
2020
Androgenetic alopecia (AGA) is a multifactorial disease that carries a significant psychological burden with it. Dihydrotestosterone, the main pathogenic androgen in AGA, is produced by conversion of testosterone, which is catalyzed by the 5-alpha reductase (5-AR) isoenzyme family. Finasteride and dutasteride are inhibitors of these enzymes. Finasteride, which is a single receptor 5-alpha reductase inhibitor (5-ARI), acts by blocking dihydrotestosterone (DHT). Dutasteride, a dual receptor DHT blocker, has a higher potency than its predecessor, finasteride. This review corroborates the evidence of superiority of dutasteride over finasteride, and its comparable safety profile concerning ferti…
Combined oral prolonged-release oxycodone and naloxone in chronic pain management
2013
Introduction: The use of opioids is associated with unwanted adverse effects, particularly opioid-induced constipation (OIC). The adverse effects of opioids on gastrointestinal function are mediated by the interaction with opioid receptors in the gastrointestinal tract. The most common drugs used for relieving OIC are laxatives, which do not address the opioid receptor-mediated bowel dysfunction and do not provide sufficient relief. Areas covered: This paper discusses the role of a combination of prolongedrelease formulation of oxycodone (OX) and naloxone (N) in the prevention and management of OIC, reporting efficacy and safety outcome of controlled studies. In a therapeutic area of great …
Ro 15-4513 Antagonizes Alcohol-Induced Sedation in Mice Through αβγ2-type GABAA Receptors
2011
Ethyl alcohol (ethanol) has many molecular targets in the nervous system, its potency at these sites being low compared with those of sedative drugs. This has made it difficult to discover ethanol’s binding site(s). There are two putative binding sites at gamma-aminobutyric acid (GABA) type A receptor subtypes for the proposed ethanol antagonist Ro 15-4513, the established gamma2 subunit-dependent benzodiazepine site and the recently reported delta subunit-dependent Ro 15-4513/ethanol binding site. Here, we aimed at clarifying the in vivo role of Ro 15-4513 at these two sites. We found that the antagonism of ethanol actions by Ro 15-4513 in wildtype mice was dependent on the test: an open f…