Publications

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growth and death of rohon-beard cells in rana pipiens and ceratophrys ornata.rohon-beard (r-b) neurons of the medulla oblongata and spinal cord of anurans originate during gastrulation, become distinguishable just after closure of the neural tube, and are present in maximum numbers at the end of the embryonic period, just before feeding begins. cell deaths are first seen in the earliest larval stages; in rana pipiens and ceratophrys ornata, they may not be complete until the very end of larval development or a day or two later, in the juvenile froglet. this is in sharp c ...19979068202
hormonal induction of spawning in 4 species of frogs by coinjection with a gonadotropin-releasing hormone agonist and a dopamine antagonist.it is well known that many anurans do not reproduce easily in captivity. some methods are based on administration of mammalian hormones such as human chorionic gonadotropin, which are not effective in many frogs. there is a need for simple, cost-effective alternative techniques to induce spawning.201020398399
a brucella spp. isolate from a pac-man frog (ceratophrys ornata) reveals characteristics departing from classical brucellae.brucella are highly infectious bacterial pathogens responsible for brucellosis, a frequent worldwide zoonosis. the brucella genus has recently expanded from 6 to 11 species, all of which were associated with mammals; the natural host range recently expanded to amphibians after some reports of atypical strains from frogs. here we describe the first in depth phenotypic and genetic characterization of a brucella strains isolated from a frog. strain b13-0095 was isolated from a pac-man frog (ceratop ...201627734009
apoptosis in larval and frog skin of rana pipiens, r. catesbeiana, and ceratophrys ornata.apoptosis (programmed cell death) occurs during normal development of anurans in organs such as gills, gut, and tail. for example, apoptotic cells have been reported in the luminal epithelium along the length of the digestive tract of both larvae and frogs; however, timing of the peak number of such cells varies in different species. the purpose of the present study was to ascertain whether apoptosis also varies by species during metamorphic restructuring of the skin (as larval epithelium is rep ...201424127169
old and new hypotheses about the homology of the compound bones from the cheek and otico-occipital regions of the anuran skull.we studied the larval development of compound bones from the otico-occipital and cheek regions in species of the neobatrachian genera batrachyla, hylorina, leptodactylus, odontophrynus and pleurodema. comparisons were made using a set of ambystoma spp. (caudata) and ceratophrys ornata (anura; ceratophryidae) larvae. as suggested by previous studies, we verified the compound nature of the exoccipital (two centers, anurans only), frontoparietal (one center, most anurans and ambystoma; three center ...201323835144
metabolic responses of the south american ornate horned frog (ceratophrys ornata) to estivation.we examined the metabolic responses of the south american frog, ceratophrys ornata, to laboratory-induced estivation. whole-animal and mass-specific oxygen consumption rates (vo(2)) did not change during fasting or 56days of estivation, despite observing significant decreases in body mass. the maintenance of mass-specific metabolic rate at routine levels during estivation suggests that metabolic rate suppression is not a major response to estivation in this species. there was a significant decli ...201322902863
apoptosis in the digestive tract of herbivorous rana pipiens larvae and carnivorous ceratophrys ornata larvae: an immunohistochemical study.the lifespan of herbivorous rana pipiens larvae is ∼3 months, while that of carnivorous ceratophrys ornata larvae is only about 2 weeks. during metamorphic climax, the larval gut shortens dramatically, especially in r. pipiens, and its luminal epithelium is replaced by adult-type epithelium. to determine when programmed cell death occurs during the metamorphic restructuring of the gut, we prepared cross-sections of the stomach, small intestine, and large intestine from representative larval stag ...201221935976
chromosome banding in amphibia. ix. the polyploid karyotypes of odontophrynus americanus and ceratophrys ornata (anura, leptodactylidae).the somatic and meiotic chromosomes of the south american leptodactylid toads odontophrynus americanus, ceratophyrys ornata, and c. cranwelli were analysed both with conventional staining and differential banding techniques. the karyotypes of o. americanus were tetraploid; those of c. ornata octaploid. ceratophrys cranwelli is a diploid species whose karyotype displays great similarities with that of c. ornata. the high frequency of multivalent pairing configurations in the meioses of o. america ...19853979176
histology and lectin-binding patterns in the skin of the terrestrial horned frog ceratophrys ornata.the terrestrial horned frog, ceratophrys ornata, lives on a wet substratum and absorbs water through the ventral epidermis; water is lost by evaporation from the dorsal skin. thus, this species may be useful as a model for determining whether or not skin histology and lectin-binding patterns, indicative of glycoconjugates, are related to skin functions such as osmoregulation and water balance. with this in mind, a histological and lectin-histochemical study was carried out on dorsal and ventral ...19957621521
histology and lectin-binding patterns in the digestive tract of the carnivorous larvae of the anuran, ceratophrys ornata.larvae of ceratophrys ornata are carnivorous, have relatively short digestive tracts and continue to feed during metamorphic climax, in contrast to those of more typical herbivorous anuran larvae. the present study describes both histological and histochemical changes in the stomach, small intestine, and large intestine of c. ornata prior to and during metamorphic climax. modifications in these organs were found to be similar to but less dramatic than those in herbivorous larvae. luminal epithel ...199910398322
effects of meal size, meal type, and body temperature on the specific dynamic action of anurans.specific dynamic action (sda), the increase in metabolism stemming from meal digestion and assimilation, varies as a function of meal size, meal type, and body temperature. to test predictions of these three determinants of sda, we quantified and compared the sda responses of nine species of anurans, bombina orientalis, bufo cognatus, ceratophrys ornata, dyscophus antongilli, hyla cinerea, kassina maculata, kassina senegalensis, pyxicephalus adspersus, and rana catesbeiana subjected to meal size ...200717106741
insulin and proglucagon-derived peptides from the horned frog, ceratophrys ornata (anura:leptodactylidae).insulin and peptides derived from the processing of proglucagon have been isolated from an extract of the pancreas of the south american horned frog, ceratophrys ornata (leptodactylidae). ceratophrys insulin is identical to the insulin previously isolated from the toad, bufo marinus (bufonidae). ceratophrys glucagon was isolated in two molecular forms with 29- and 36-amino acid residues in approximately equal amounts. glucagon-29 is identical to glucagon from b. marinus and from the bullfrog, ra ...199910375473
a different type of amphibian mesoderm morphogenesis in ceratophrys ornata.ceratophrys ornata, the argentinean horned frog, has a significantly different pattern of early morphogenesis than does the most studied amphibian, xenopus laevis. time-lapse videomicroscopy, scanning electron microscopy, histological sections and lineage tracers have shown that, in c. ornata, some prospective notochord, somite and tailbud mesoderm cells leave the surface epithelium of the archenteron by ingression. after gastrulation, sem reveals cells with constricted apices and a bottle shape ...19938223254
[cytogenetics of amphibious anura of south america. the chromosomes of odontophrynus americanus and ceratophrys ornata]. 195914440731
the aneupolyploid complement of ceratophrys ornata. 20035703377
response of immature gonads of ceratophrys ornata to fsh. 19715550924
ribosomal rna structure in the diploid and phylogenetically polyploid amphibian species hyla and odontophrynus.ribosomal rna of the diploid amphibian species hyla chrysoscelis and odontophrynus americanus is structurally modified by hidden breaks. phylogenetically polyploid related species like the tetraploid hyla versicolor, the tetraploid odontophrynus americanus and the octoploid ceratophrys ornata do not show hidden breaks in ribosomal rna. structural modifications of rrna molecules in diploid amphibians has no detectable effect on the ribosomal activity in vitro.19846509913
physiological responses to feeding, fasting and estivation for anurans.anuran estivation is characterized by long episodes of aphagia. to investigate whether estivating anurans downregulate intestinal performance as an adaptive mechanism to reduce energy expenditure, i compared the metabolic and intestinal responses to feeding, fasting and estivation among non-estivating and estivating species of the anuran families bufonidae, leptodactylidae and ranidae. standard metabolic rates of the estivating bufo alvarius, ceratophrys ornata and pyxicephalus adspersus were si ...200515961745
serous cutaneous glands in the south american horned frog ceratophrys ornata (leptodactylformes, chthonobatrachia, ceratophrydae): ultrastructural expression of poison biosynthesis and maturation.serous cutaneous glands are described in newly metamorphosed and juvenile specimens of the horned frog ceratophrys ornata using light and transmission electron microscopy. we report patterns of biosynthesis and maturation of the specific product of the gland secretory unit. the syncytial, secretory compartment possesses a complex of endoplasmic reticulum (predominantly smooth endoplasmic reticulum after metamorphosis) and golgi stacks. the serous product is weak in density and is contained in ve ...200717492781
acoustic underwater signals with a probable function during competitive feeding in a tadpole.acoustic communication is widespread among adult stages of terrestrial animals and fish and has also been observed in insect larvae. we report underwater acoustic communication in the larvae of a frog, gephyromantis azzurrae, from isalo, a sandstone massif in western madagascar. according to our field data, these tadpoles live in streams and prefer habitats characterized by comparatively low temperatures, shallow water depth, and a relatively fast current. feeding experiments indicated that the ...201121161155
tadpoles of the horned frog ceratophrys ornata exhibit high sensitivity to chlorpyrifos for conventional ecotoxicological and novel bioacoustic variables.previous studies reported that some species of the family ceratophryidae are able to produce sounds during premetamorphic tadpole stages. we have now determined the effects of the cholinesterase-inhibiting insecticide chlorpyrifos (cpf) on sounds emitted by tadpoles of ceratophrys ornata. tadpoles were exposed individually in order to evaluate the progression of effects. effects on sound production were complemented with common ecotoxicological endpoints (mortality, behavior, abnormalities and g ...201829751398
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