419 resultados para South American blastomycosis
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Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.
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The South American pepper frog, Leptodactylus labyrinthicus, is a large species that lays eggs in foam nests in holes dug out of the banks of different bodies of water. Recently, it was reported that only 6-10% of eggs are fertilized in foam nests of L. labyrinthicus and the remaining unfertilized eggs are consumed by the tadpoles inside the nest. Here we tested experimentally the influence of the ingestion of trophic eggs on the survivorship and growth of L. labyrinthicus tadpoles. Tadpoles fed on trophic eggs and subsequently fed on dry fish food grew larger than those fed only on dry fish food, and this suggests that the ingestion of trophic eggs is an adaptation to improve tadpole growth. The ingestion of trophic eggs also seems to be important for the maintenance of tadpoles in environments with unpredictable rainfall, as they were able to survive for about 70 days feeding only on these trophic eggs and one tadpole managed to complete metamorphosis feeding on trophic eggs only. Details of the spawning behaviour observed in the field, occurrence of multiple mating, and predation on eggs by terrestrial invertebrates and vertebrates are also reported.
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Hylidae is a large family of American, Australopapuan, and temperate Eurasian treefrogs of approximately 870 known species, divided among four subfamilies. Although some groups of Hylidae have been addressed phylogenetically, a comprehensive phylogenetic analysis has never been presented. The first goal of this paper is to review the current state of hylid systematics. We focus on the very large subfamily Hylinae (590 species), evaluate the monophyly of named taxa, and examine the evidential basis of the existing taxonomy. The second objective is to perform a phylogenetic analysis using mostly DNA sequence data in order to (1) test the monophyly of the Hylidae; (2) determine its constituent taxa, with special attention to the genera and species groups which form the subfamily Hylinae, and c) propose a new, monophyletic taxonomy consistent with the hypothesized relationships. We present a phylogenetic analysis of hylid frogs based on 276 terminals, including 228 hylids and 48 outgroup taxa. Included are exemplars of all but 1 of the 41 genera of Hylidae (of all four nominal subfamilies) and 39 of the 41 currently recognized species groups of the species-rich genus Hyla. The included taxa allowed us to test the monophyly of 24 of the 35 nonmonotypic genera and 25 species groups of Hyla. The phylogenetic analysis includes approximately 5100 base pairs from four mitochondrial (12S, tRNA valine, 16S, and cytochrome b) and five nuclear genes (rhodopsin, tyrosinase, RAG-1, seventh in absentia, and 28S), and a small data set from foot musculature. Concurring with previous studies, the present analysis indicates that Hemiphractinae are not related to the other three hylid subfamilies. It is therefore removed from the family and tentatively considered a subfamily of the paraphyletic Leptodactylidae. Hylidae is now restricted to Hylinae, Pelodryadinae, and Phyllomedusinae. Our results support a sister-group relationship between Pelodryadinae and Phyllomedusinae, which together form the sister taxon of Hylinae. Agalychnis, Phyllomedusa, Litoria, Hyla, Osteocephalus, Phrynohyas, Ptychohyla, Scinax, Smilisca, and Trachycephalus are not monophyletic. Within Hyla, the H. albomarginata, H. albopunctata, H. arborea, H. boons, H. cinerea, H. eximia, H. geographica, H. granosa, H. microcephala, H. miotympanum, H. tuberculosa, and H. versicolor groups are also demonstrably nonmonophyletic. Hylinae is composed of four major clades. The first of these includes the Andean stream-breeding Hyla, Aplastodiscus, all Gladiator Frogs, and a Tepuian clade. The second clade is composed of the 30-chromosome Hyla, Lysapsus, Pseudis, Scarthyla, Scinax (including the H. uruguaya group), Sphaenorhynchus, and Xenohyla. The third major clade is composed of Nyctimantis, Phrynohyas, Phyllodytes, and all South American/West Indian casque-headed frogs: Aparasphenodon, Argenteohyla, Corythomantis, Osteocephalus, Osteopilus, Tepuihyla, and Trachycephalus. The fourth major clade is composed of most of the Middle American/Holarctic species groups of Hyla and the genera Acris, Anotheca, Duellmanohyla, Plectrohyla, Pseudacris, Ptychohyla, Pternohyla, Smilisca, and Triprion. A new monophyletic taxonomy mirroring these results is presented where Hylinae is divided into four tribes. Of the species currently in Hyla, 297 of the 353 species are placed in 15 genera; of these, 4 are currently recognized, 4 are resurrected names, and 7 are new. Hyla is restricted to H. femoralis and the H. arborea, H. cinerea, H. eximia, and H. versicolor groups, whose contents are redefined. Phrynohyas is placed in the synonymy of Trachycephalus, and Pternohyla is placed in the synonymy of Smilisca. The genus Dendropsophus is resurrected to include all former species of Hyla known or suspected to have 30 chromosomes. Exerodonta is resurrected to include the former Hyla sumichrasti group and some members of the former H. miotympanum group. Hyloscirtus is resurrected for the former Hyla armata, H. bogotensis, and H. larinopygion groups. Hypsiboas is resurrected to include several species groups - many of them redefined here - of Gladiator Frogs. The former Hyla albofrenata and H. albosignata complexes of the H. albomarginata group are included in Aplastodiscus. New generic names are erected for (1) Agalychnis calcarifer and A. craspedopus; (2) Osteocephalus langsdorffii; the (3) Hyla aromatica, (4) H. bromeliacia, (5) H. godmani, (6) H. mixomaculata, (7) H. taeniopus, (8) and H. tuberculosa groups; (9) the clade composed of the H. pictipes and H. pseudopuma groups; and (10) a clade composed of the H. circumdata, H. claresignata, H. martinsi, and H. pseudopseudis groups. Copyright © American Museum of Natural History 2005.
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The epididymal epithelium of Agouti paca, a wild South American rodent, was basically formed by principal and basal cells. Principal cells were closely related to processes of adsorptive endocytosis, phasefluid endocytosis and also secretion originating from their cytoplasmic ultrastructural features. Principal cells were also characterized by the presence of vesicles of several shapes, sizes and internalized content occurring in smaller pits, pale small vesicles next to the apical brush border of microvillus, as well as coated vesicles, smooth surface vesicles and great vesicles. Multivesicular bodies, endosomes and lysosomes were mainly observed in supranuclear position. Moreover, presence of an apocrine secretory process was demonstrated by the occurrence of apical cytoplasmic expansions projecting into the vas deferens luminal compartment. Basal flattened cells without luminal surface contact occurred next to the basement membrane of the ductus, and did no exhibit special ultrastructural features.
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Chionanthus greenii Lombardi, a new species of Oleaceae, is described and illustrated. It is distinguished by the unique combination of strigose indument, short congested inflorescences, small corolla lobes and reniform anthers, which do not match any described South American species. © The Board of Trustees of the Royal Botanic Gardens, 2006.
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The sensing of blood gas tensions and/or pH is an evolutionarily conserved, homeostatic mechanism, observable in almost all species studied from invertebrates to man. In vertebrates, a shift from the peripheral O2-oriented sensing in fish, to the central CO2/pH sensing in most tetrapods reflects the specific behavioral requirements of these two groups whereby, in teleost fish, a highly O2-oriented control of breathing matches the ever-changing and low oxygen levels in water, whilst the transition to air-breathing increased the importance of acid-base regulation and O2-related drive, although retained, became relatively less important. The South American lungfish and tetrapods are probably sister groups, a conclusion backed up by many similar features of respiratory control. For example, the relative roles of peripheral and central chemoreceptors are present both in the lungfish and in land vertebrates. In both groups, the central CO2/pH receptors dominate the ventilatory response to hypercarbia (60-80), while the peripheral CO2/pH receptors account for 20-30. Some basic components of respiratory control have changed little during evolution. This review presents studies that reflect the current trends in the field of chemoreceptor function, and several laboratories are involved. An exhaustive review on the previous literature, however, is beyond the intended scope of the article. Rather, we present examples of current trends in respiratory function in vertebrates, ranging from fish to humans, and focus on both O2 sensing and CO2 sensing. As well, we consider the impact of chronic levels of hypoxia - a physiological condition in fish and in land vertebrates resident at high elevations or suffering from one of the many cardiorespiratory disease states that predispose an animal to impaired ventilation or cardiac output. This provides a basis for a comparative physiology that is informative about the evolution of respiratory functions in vertebrates and about human disease. Currently, most detail is known for mammals, for which molecular biology and respiratory physiology have combined in the discovery of the mechanisms underlying the responses of respiratory chemoreceptors. Our review includes new data on nonmammalian vertebrates, which stresses that some chemoreceptor sites are of ancient origin.
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We present the first complete study of basic laboratory-measured physiological variables (metabolism, thermoregulation, evaporative water loss, and ventilation) for a South American marsupial, the gracile mouse opossum (Gracilinanus agilis). Body temperature (Tb) was thermolabile below thermoneutrality (Tb = 33.5°C), but a substantial gradient between Tb and ambient temperature (Ta) was sustained even at Ta = 12°C (Tb = 30.6°C). Basal metabolic rate of 1.00 mL O2 g-1 h-1 at Ta = 30°C conformed to the general allometric relationship for marsupials, as did wet thermal conductance (5.7 mL O2 g-1 h-1 °C-1). Respiratory rate, tidal volume, and minute volume at thermoneutrality matched metabolic demand such that O2 extraction was 12.4%, and ventilation increased in proportion to metabolic rate at low T a. Ventilatory accommodation of increased metabolic rate at low Ta was by an increase in respiratory rate rather than by tidal volume or O2 extraction. Evaporative water loss at the lower limit of thermoneutrality conformed to that of other marsupials. Relative water economy was negative at thermoneutrality but positive below Ta = 12°C. Interestingly, the Neotropical gracile mouse opossums have a more positive water economy at low Ta than an Australian arid-zone marsupial, perhaps reflecting seasonal variation in water availability for the mouse opossum. Torpor occurred at low Ta, with spontaneous arousal when . T b > 20°C. Torpor resulted in absolute energy and water savings but lower relative water economy. We found no evidence that gracile mouse opossums differ physiologically from other marsupials, despite their Neotropical distribution, sympatry with placental mammals, and long period of separation from Australian marsupials. © 2009 by The University of Chicago. All rights reserved.
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Background. Several pathogens that cause important zoonotic diseases have been frequently associated with armadillos and other xenarthrans. This mammal group typically has evolved on the South American continent and many of its extant species are seriously threatened with extinction. Natural infection of armadillos with Paracoccidioides brasiliensis in hyperendemic areas has provided a valuable opportunity for understanding the role of this mammal in the eco-epidemiology of Paracoccidioidomycosis (PCM), one of the most important systemic mycoses in Latin America. Findings. This study aimed to detect P. brasiliensis in different xenarthran species (Dasypus novemcinctus, Cabassous spp., Euphractus sexcinctus, Tamandua tetradactyla and Myrmecophaga tridactyla), by molecular and mycological approaches, in samples obtained by one of the following strategies: i) from road-killed animals (n = 6); ii) from naturally dead animals (n = 8); iii) from animals that died in captivity (n = 9); and iv) from living animals captured from the wild (n = 2). Specific P. brasiliensis DNA was detected in several organs among 7/20 nine-banded armadillos (D. novemcinctus) and in 2/2 anteaters (M. tridactyla). The fungus was also cultured in tissue samples from one of two armadillos captured from the wild. Conclusion. Members of the Xenarthra Order, especially armadillos, have some characteristics, including a weak cellular immune response and low body temperature, which make them suitable models for studying host-pathogen interaction. P. brasiliensis infection in wild animals, from PCM endemic areas, may be more common than initially postulated and reinforces the use of these animals as sentinels for the pathogen in the environment. © 2009 Bagagli et al; licensee BioMed Central Ltd.
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It is well established that nitrate is a potent inhibitor of nodulation and nitrogen fixation in legumes. The objective of this study was to demonstrate the relative insensitivity of these processes to nitrate with Calopogonium mucunoides, a tropical South American perennial legume, native to the cerrado (savannah) region. It was found that nodule number was reduced by about half in the presence of high levels of nitrate (15 mM) but nodule growth (total nodule mass per plant) and nitrogen fixation (acetylene reduction activity and xylem sap ureide levels) were not affected. Other sources of N (ammonium and urea) were also without effect at these concentrations. At even higher concentrations (30 mM), nitrate did promote significant inhibition (ca. 50%) of acetylene reduction activity, but no significant reduction in xylem sap ureides was found. The extraordinary insensitivity of nodulation and N2 fixation of C. mucunoides to nitrate suggests that this species should be useful in studies aimed at elucidating the mechanisms of nitrate inhibition of these processes. © 2010 Springer Science+Business Media B.V.
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Knowledge about the species distribution of Epipompilus Kohl, 1884, is largely based on the records from the species description. Recent efforts in South American bodiversity studies indicate that knowledge about the distribution of Epipompilus species in the region is in an early stage. Two new records of E. aztecus were obtained for the semideciduous Atlantic Forest, in central Brazil, and one record for the Amazonian Forest in northern Brazil, indicating that its distribution extends between Central and South America. The new records of E. excelsus were obtained mainly from the Atlantic Forest highlands, indicating that this species is commonly found in the southeastern South American Central Plateau and restricted to forest ecosystem of this region. © 2010 Eduardo Fernando dos Santos and Fernando Barbosa Noll.
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Among the physiographic regions included in the central South American diagonal of open formations, the Chaco, with some endemic species, represents the southernmost dry area. In Brazil, the Chaco is found in southwestern corner of Mato Grosso do Sul state, mostly in the municipality of Porto Murtinho along the Paraguay and Apa rivers. From February 2008 to December 2009, we carried out an inventory of amphibians and reptiles in Porto Murtinho, using pitfall traps, time-limited searches, and occasional encounters. A total of 34 amphibian and 39 reptile species were registered. Although some typical Chacoan species were found, most of the species are open area dwellers that also occur in other open biomes, such as the Cerrado and Caatinga. © 2010 Check List and Authors.
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Five South-American species of the genus Ocotea from Bahia, Brazil, are described and illustrated. The new species are Ocotea adamantina, O. rohweri, O. sperata, O. thinicola, and O. vegrandis. Their relationships within the genus are discussed. © President and Fellows of Harvard College, 2011.
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Introduction. Physical activity can provide long-term benefits for systemic lupus erythematosus (SLE). Objective. This study sought to demonstrate the effects of progressive resistance training on the muscular strength, bone mineral density (BMD) and body composition of pre-menopausal women with SLE undergoing glucocorticoid (GC) treatment. Materials and Methods. This is the case report of a 43-year-old African-South American premenopausal woman with non-extensive SLE and low bone density. A six-month program with three bimonthly cycles of 70%, 80%, and 90% intensity according to the 10 maximum-repetition test was used. Dual-energy X-ray absorptiometry (DXA) was used to measure the BMD, T-scores and body composition, and indirect fluorescence was used to measure the levels of antinuclear antibodies. Student's t-test was used. Results. Statistical improvement was noted in all strength exercises, including the 45° leg press (Δ%=+50%, p<0.001) and knee extension (Δ%=+15%, p=0.003) to maintain the BMD of the L2-L4 lumbar (Δ%=+0.031%; p=0.46) as well as the trochanter (Δ%=+0.037%; p=0.31) and BMI (Δ%=-0.8, p=0.54). Conclusion. In this case study, the presented methodology had a positive effect on strength and contributed to the maintenance of BMD and body composition in a woman with SLE undergoing GC treatment. © 2012 Revista Andaluza de Medicina del Deporte.
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Context The bush dog (Speothos venaticus) is difficult to observe, capture, and study. To date, indirect evidence and opportunistic field observations have been the primary sources of information about the species' ecology. Field data are urgently needed to clarify the species' ecological requirements, behaviour and movement patterns. Aims The present study uses 13 months of telemetry data from a group of bush dogs to begin to address questions about area requirements, habitat preferences and movement patterns of this difficult-to-study species. Methods We tracked a group of bush dogs (two adults, one juvenile, four young) in an area of intact and altered Cerrado (woodlandsavanna biome) in eastern Mato Grosso, Brazil (Nova Xavantina District). Key results The group had a total home range of 140km2 (fixed kernel 95%), with smaller seasonal 'subareas' (areas used for 12 months before moving to another area, with repetition of some areas over time) and demonstrated a preference for native habitats. Conclusions The bush dog's home range is greater than that of other canids of the same size, even correcting for group size. Patterns of seasonal movement are also different from what has been observed in other South American canids. Implications From our observations in the Brazilian savanna, bush dogs need large tracks of native habitat for their long-term persistence. Although the present study is based on a single pack, it is highly relevant for bush dog conservation because it provides novel information on the species' spatial requirements and habitat preferences. © 2012 CSIRO.
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Brazil adopted SIRGAS2000 in 2005. This adoption called for the provision of the relationships between SIRGAS2000 and the previous reference frames used for positioning, mapping and GIS, namely, the Córrego Alegre (CA) and the South American Datum of 1969 (SAD 69). Two programs were designed for this purpose. The first one, TCGeo, provided the relationships based on three-translation Similarity Transformation parameters. TCGeo was replaced in December 2008, by ProGriD. ProGriD offers, besides the same similarity transformation as TCGeo, a set of transformations based on modelling the distortions of the networks used in the various realizations of CA and SAD 69. The distortion models are represented by a grid in which each node contains a transformation value in terms of difference in latitude and in longitude. The grid follows the same specifications of the NTv2 grid, which has been used in other countries, such as Canada, USA and Australia. This paper presents ProGriD and its main functionalities and capabilities. ©Springer-Verlag Berlin Heidelberg 2012.