Showing papers on "Mantella published in 2016"
TL;DR: This study is the first to demonstrate the genetic basis of autoresistance in frogs with alkaloid defenses, and predicts that poison frogs are somewhat resistant to these compounds because they have six types of amino acid replacements in the Nav1.4 inner pore.
Abstract: Complex phenotypes typically have a correspondingly multifaceted genetic component. However, the genotype–phenotype association between chemical defense and resistance is often simple: genetic changes in the binding site of a toxin alter how it affects its target. Some toxic organisms, such as poison frogs (Anura: Dendrobatidae), have defensive alkaloids that disrupt the function of ion channels, proteins that are crucial for nerve and muscle activity. Using protein-docking models, we predict that three major classes of poison frog alkaloids (histrionicotoxins, pumiliotoxins, and batrachotoxins) bind to similar sites in the highly conserved inner pore of the muscle voltage-gated sodium channel, Nav1.4. We predict that poison frogs are somewhat resistant to these compounds because they have six types of amino acid replacements in the Nav1.4 inner pore that are absent in all other frogs except for a distantly related alkaloid-defended frog from Madagascar, Mantella aurantiaca. Protein-docking models and comparative phylogenetics support the role of these replacements in alkaloid resistance. Taking into account the four independent origins of chemical defense in Dendrobatidae, phylogenetic patterns of the amino acid replacements suggest that 1) alkaloid resistance in Nav1.4 evolved independently at least seven times in these frogs, 2) variation in resistance-conferring replacements is likely a result of differences in alkaloid exposure across species, and 3) functional constraint shapes the evolution of the Nav1.4 inner pore. Our study is the fi rst to demon strate the genetic basis of autoresistance in frogs with alkaloid defenses.
53 citations
TL;DR: Madagascar is one of the world's most recognized biodiversity hotspots and has a diverse assassin bug (Reduviidae) fauna that is still incompletely known, especially for the Ectrichodiinae, or millipede assassin bugs, but dramatic undescribed species-level diversity is revealed.
Abstract: Madagascar is one of the world's most recognized biodiversity hotspots and has a diverse assassin bug (Reduviidae) fauna that is still incompletely known, especially for the Ectrichodiinae, or millipede assassin bugs. Ectrichodiinae are a speciose (673 described species, 118 genera), worldwide group of assassin bugs that is most diverse in the Old and New World tropics, but so far only six genera and 10 species have been described from Madagascar. Based on examination of 1981 ectrichodiine specimens mostly from the California Academy of Sciences, as well as a few other collections, dramatic undescribed species-level diversity is revealed. The island's Ectrichodiinae fauna is taxonomically revised with the description of three new genera (Marojejycoris, Tanindrazanus, and Toliarus) and 63 new species: Gibbosella andasibe, Gibbosella betampona, Gibbosella brunalvus, Gibbosella conisimilis, Gibbosella fulva, Gibbosella mantella, Gibbosella megafrons, Gibbosella nitida, Gibbosella notoconica, Gibbose...
14 citations
30 May 2016
TL;DR: These frogs are collected for the international pet trade for their small size and the iridescent color of their skin and the aposematic colorations result from particular toxic secretions.
Abstract: Nowadays, there are 16 named species of Mantella frogs. However, some other species are waiting for the determination of their status. These frogs are currently endangered by the lost of their habitats and the poaching. These frogs are collected for the international pet trade for their small size (less than 5 cm) and the iridescent color of their skin. These aposematic colorations result from particular toxic secretions. Their skin poisons mainly contain mixtures of alkaloid molecules. These mixtures have been reported to vary according to geographical location, season, and diet of the frog [1-2].