Publications

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alkaloids in madagascan frogs (mantella): pumiliotoxins, indolizidines, quinolizidines, and pyrrolizidines.brightly colored ranid frogs of the genus mantella are found only in rain forests of madagascar. gc-ms and gc-ft-ir analyses of skin alkaloids of seven different species, including four populations of mantella madagascariensis, are reported. all contain one or more representatives of the pumiliotoxin a (ptx-a) class with the 13,14-dihydro derivatives 309a and 325a found in major amounts in the four populations of m. madagascariensis, while 307a (ptx-a) is found in two populations of m. madagasca ...19938377013
the tonic immobility test: do wild and captive golden mantella frogs (mantella aurantiaca) have the same response?adaptations to captivity that reduce fitness are one of many reasons, which explain the low success rate of reintroductions. one way of testing this hypothesis is to compare an important behavioural response in captive and wild members of the same species. thanatosis, is an anti-predator strategy that reduces the risk of death from predation, which is a common behavioral response in frogs. the study subjects for this investigation were captive and wild populations of mantella aurantiaca. thanato ...201728732029
convergent substitutions in a sodium channel suggest multiple origins of toxin resistance in poison frogs.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 th ...201626782998
individual and geographic variation of skin alkaloids in three swamp-forest species of madagascan poison frogs (mantella).seventy skins of three mantellid frog species from madagascan swamp-forest habitats, mantella aurantiaca, m. crocea, and m. milotympanum, were individually examined for skin alkaloids using gc/ms. these poison frogs were found to differ significantly in their alkaloid composition from species of mantella originating from non-flooded rainforest in eastern madagascar, which were examined in earlier work. only 16 of the previously detected 106 alkaloids were represented among the 60 alkaloids from ...201526329921
absence of skin alkaloids in captive-raised madagascan mantelline frogs (mantella) and sequestration of dietary alkaloids.mantelline frogs of the genus mantella contain a variety of pumiliotoxin, allopumiliotoxin and homopumiliotoxin alkaloids in their skin. pyrrolizidines, indolizidines and quinolizidines are also present. in contrast, captive-raised frogs (mantella aurantiaca) have no alkaloids detectable in skin extracts. frogs fed alkaloid-dusted fruit flies accumulate alkaloids into their skin. thus, these mantelline frogs, like the neotropical dendrobatid frogs, appear dependent on dietary sources for their s ...19979248011
new evidence for parallel evolution of colour patterns in malagasy poison frogs (mantella).malagasy poison frogs of the genus mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. here, we provide cytochrome b data for 143 individuals of three species in the mantella madagascariensis group, includin ...200415548289
occurrence of skin alkaloids in non-dendrobatid frogs from brazil (bufonidae), australia (myobatrachidae) and madagascar (mantellinae).several taxa of small frogs from the southern hemisphere contain alkaloids similar or identical to compounds previously known only from neotropical poison frogs of the family dendrobatidae. skin of the brazilian toad melanophryniscus moreirae (family bufonidae) contains a new alkaloid 8-hydroxy-8-methyl-6-(5'-hydroxy-2'-methyl-hexylidene)-1-azabicycl o-[4.3.0] nonane (c16h29no2), which is designated pumiliotoxin 267c. such a structure is typical of the pumiliotoxin-a class of dendrobatid alkaloi ...19846523513
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