20 resultados para cerrado species

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Miconia langsdorffii Cogn. (Melastomataceae), Roupala montana Aubl. (Proteaceae), Struthanthus syringifolius (Mart.) (Loranthaceae), and Schefflera vinosa (Cham. & Schltdl.) Frodin (Araliaceae) are plant species from the Brazilian Cerrado whose schistosomicidal potential has not yet been described. The crude extracts, fractions, the triterpenes betulin, oleanolic acid, ursolic acid and the flavonoids quercetin 3-O-beta-D-rhamnoside, quercetin 3-O-beta-D-glucoside, quercetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside and isorhamnetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside were evaluated in vitro against Schistosoma mansoni adult worms and the bioactive n-hexane fractions of the mentioned species were also analyzed by GC-MS. Betulin was able to cause worm death percentage values of 25% after 120 h (at 100 mu M), and 25% and 50% after 24 and 120 h (at 200 mu M), respectively; besides the flavonoid quercetin 3-O-beta-D-rhamnoside promoted 25% of death of the parasites at 100 mu M. Farther the flavonoids quercetin 3-O-beta-D-glucoside and quercetin 3-O-beta-D-rhamnoside at 100 mu M exhibited significantly reduction in motor activity, 75% and 87.5%, respectively. Biological results indicated that crude extracts of R. montana, S. vinosa, and M. langsdorffii and some n-hexane and EtOAc fractions of this species were able to induce worm death to some extent. The results suggest that lupane-type triterpenes and flavonoid monoglycosides should be considered for further antiparasites studies.

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The gecko genus Phyllopezus occurs across South America's open biomes: Cerrado, Seasonally Dry Tropical Forests (SDTF, including Caatinga), and Chaco. We generated a multi-gene dataset and estimated phylogenetic relationships among described Phyllopezus taxa and related species. We included exemplars from both described Phyllopezus pollicaris subspecies, P. p. pollicaris and P. p. przewalskii. Phylogenies from the concatenated data as well as species trees constructed from individual gene trees were largely congruent. All phylogeny reconstruction methods showed Bogertia lutzae as the sister species of Phyllopezus maranjonensis, rendering Phyllopezus paraphyletic. We synonymized the monotypic genus Bogertia with Phyllopezus to maintain a taxonomy that is isomorphic with phylogenetic history. We recovered multiple, deeply divergent, cryptic lineages within P. pollicaris. These cryptic lineages possessed mtDNA distances equivalent to distances among other gekkotan sister taxa. Described P. pollicaris subspecies are not reciprocally monophyletic and current subspecific taxonomy does not accurately reflect evolutionary relationships among cryptic lineages. We highlight the conservation significance of these results in light of the ongoing habitat loss in South America's open biomes. (C) 2011 Elsevier Inc. All rights reserved.

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A new species of Pseudopaludicola is described from the Cerrado of southeastern Brazil. The new taxon is diagnosed from the P. pusilla species group by the absence of either T-shaped terminal phalanges or toe tips expanded, and promptly distinguished from all (13) recognized taxa currently assigned to Pseudopaludicola by possessing isolated (instead of regular call series), long (117-187 ms) and non-pulsed advertisement calls.

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Premise of the study: Microsatellite primers were developed to investigate genetic diversity and population structure of Qualea grandiflora, a typical species of the Brazilian cerrado. Methods and Results: Eight microsatellite loci were isolated using an enrichment cloning protocol. These loci were tested on a population of 110 individuals of Q. grandiflora collected from a cerrado fragment in Sao Paulo State, Brazil. The loci polymorphism ranges from seven to 19 alleles and the average heterozygosity value is 0.568, while the average polymorphic information content is 0.799. Conclusions: The developed markers were found to be highly polymorphic, indicating their applicability to studies of population genetic diversity in Q. grandiflora

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A new species of Rhinella of Central Brazil from the Rhinella crucifer group is described. Rhinella inopina sp. nov. is restricted to the disjunct Seasonal Tropical Dry Forests enclaves in the western Cerrado biome. The new species is characterized mainly by head wider than long, shape of parotoid gland, and oblique arrangement of the parotoid gland. Data on natural history and distribution are also presented.

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This paper presents a survey of the insects that feed on fruits of Psittacanthus Martius (Santalales: Loranthaceae), a hemiparasitic mistletoe genus that infects trees in Brazil and other neotropical countries. The aim of the study was to identify candidate insects for biological control of Psittacanthus mistletoes. Unripe and mature fruits were collected in several localities of Cerrado, bordering South Pantanal, Southwestern Brazil, from 29 Apr 1998 to 30 Jul 2000. A total of 24,710 fruits (54 samples) of Psittacanthus acinarius infecting 15 species from 10 plant families were evaluated. Psittacanthus acinarius (Mart.) was the most abundant and frequent species of mistletoe parasitizing trees in the ecotonal Cerrado-Pantanal. From 24,710 fruits of Psittacanthus acinarius were obtained 1,812 insect larvae including 1,806 Neosilba McAlpine (Diptera: Lonchaeidae) species and 6 Thepytus echelta (Hewitson) (Lepidoptera: Lycaenidae). From these emerged 1,550 Neosilba spp. adults and 6 T. echelta. Neosilba pantanense Strikis was described from this research. Larvae of T. echelta occurred in fruits of P. acinarius parasitizing Cecropia pachystachya Trecul (Urticaceae) and Anadenanthera colubrina (Vellozo) Brenan (Fabaceae). Larvae of Neosilba caused no adverse effects on the germination of infected fruits of Psittacanthus, because they do not eat the embryo or viscin tissues. This differs from the larvae of T. echelta that interrupted the germination of seeds by feeding on those tissues. Thepytus echelta may be a promising insect for the biological control of P. acinarius in the ecotonal Cerrado-Pantanal, although its abundance and frequency were low throughout the sampling period.

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Guapira graciliflora and Neea theifera are taxonomically related species of the tribe Pisoneae. Both species are found in the same environment, the Brazilian Cerrado, and therefore, are subjected to similar selective pressures. These species occur in oligotrophic environments, yet contain high concentrations of nitrogen in their leaves. The present study was carried out to investigate the ecological role of nitrogen in herbivory on these species. The differences in the N content, compositions of secondary N-metabolites, mechanical resistance, and water content between their leaves indicate that these species have different adaptations as defense mechanisms. In both species, their high nitrogen content seems to promote herbivory. The presence of secondary nitrogen metabolites does not prevent the species from suffering intense damage by herbivores on their early leaves. The herbivory rates observed were lower for mature leaves of both species than for young leaves. In G. graciliflora, nutritional content and leaf hardness are the most important variables correlated with reduction of herbivory rates, whereas in N. theifera, N compounds are also correlated with herbivory rates. Despite the differences in the strategies of these two species, they exhibit a similar efficiency of protection against natural enemies because their total herbivory rates are similar. The difference in their N defense allocation may imply benefits for survival under Cerrado conditions. We briefly discuss the oligotrophic habitat conditions of the studied plants and possible advantages of their strategies of N accumulation and metabolic uses. (C) 2011 Elsevier B.V. All rights reserved.

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A new species of Trachycephalus is described for the Cerrado biome of Goias, Brazil. Trachycephalus mambaiensis sp. nov. is distinguished from the other ten species of the genus by the skin co-ossified with the skull, heavy cranial ossification, frontoparietal that fails to articulate with squamosal, absence of a crista occipitalis and secreting glands of milky and viscous substances. The skull of the new species shows an intermediary condition between species of Trachycephalus with a well ossified skull (Casque-headed frogs) and those without cranial ossification.

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A new species of Pelexia Poit. ex Until. (Orchidaceae, Spiranthinae) occurring in central Sao Paulo, southeastern Brazil, is described and illustrated as P. vinosa A. W. C. Ferreira, M. I. S. Lima & Pansarin. Pelexia vinosa is recognized by its leaves that are present at flowering and its dark purple leaf blades with reddish margins. Inflorescences are sparsely pubescent and reddish. The red sepals contrast with the white hyaline petals and labellum. The species is notable for its spurlike nectary that is parallel and adnate to the ovary. The new species is morphologically similar to P. laxa (Poepp. & Endl.) Lindl. In addition, the need to preserve native areas of the interior of Sao Paulo State (habitat of P. vinosa) is discussed.

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Habitat use by Sharp-tailed Tyrant (Culicivora caudacuta), and Cock-tailed Tyrant (Alectrurus tricolor) in the Cerrado of Southeastern Brazil. Obligatory grassland birds are dependent on a limited set of native habitats that are disappearing almost everywhere. We examined the use of macrohabitat and microhabitat by two threatened species of flycatchers, the Sharp-tailed Tyrant, Culicivora caudacuta and the Cock-tailed Tyrant, Alectrurus tricolor in a preserved area of cerrado. We generated logistic regression models to explain the presence of these species through variables of microhabitat. Both flycatchers occurred mainly in grassland areas and favored areas with a low density of palms (Attalea geraensis) and trees. The Sharp-tailed Tyrant also favored areas with a high density of low shrubs (< 1 m) and less exposed soil. The positive relationship found between the presence of Sharp-tailed Tyrant and soil cover may indicate the importance of litter and understory vegetation for shelter and food. The conservation of both flycatcher species in the study area should benefit from controlling palm density and the maintenance of grasslands with low shrubs.

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A new species of Oreobates is described from Cavernas do Peruacu National Park, Januaria, Minas Gerais state, in the Atlantic Dry Forests of Brazil. The new species is distinguished from all other Oreobates by having the following combination of characters: large tympanum, discs broadly enlarged and truncate on Fingers III and IV, smooth dorsal skin, nuptial pads absent, snout subacuminate, and a very short pulsatile (2-3 pulses) single-noted advertisement call with dominant frequency of about 3150 Hz, and no harmonic structure. Molecular phylogenetic analyses using partial sequences of the mitochondrial genes cytochrome b (cyt b) and 16S using multiple outgroups recovered the new species within Oreobates and sister to O. heterodactylus. The latter species inhabits the Dry Forests of Mato Grosso (Cerrado) and Bolivia (Chiquitano forests), and is strictly associated to these habitats, which suggests a preterit connection between Chiquitano and Atlantic Dry Forests. The discovery of a new Oreobates in the Atlantic Dry Forest is of great importance for the conservation of these dry forests, as it is known only from this type of habitat.

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Apomictic plants are less dependent on pollinator services and able to occupy more diverse habitats than sexual species. However, such assumptions are based on temperate species, and comparable evaluation for species-rich Neotropical taxa is lacking. In this context, the Melastomataceae is a predominantly Neotropical angiosperm family with many apomictic species, which is common in the Campos Rupestres, endemism-rich vegetation on rocky outcrops in central Brazil. In this study, the breeding system of some Campo Rupestre Melastomataceae was evaluated, and breeding system studies for New World species were surveyed to test the hypothesis that apomixis is associated with wide distributions, whilst sexual species have more restricted areas. The breeding systems of 20 Campo Rupestre Melastomataceae were studied using hand pollinations and pollen-tube growth analysis. In addition, breeding system information was compiled for 124 New World species of Melastomataceae with either wide (1000 km) or restricted distributions. Most (80 ) of the Campo Rupestre species studied were self-compatible. Self-incompatibility in Microlicia viminalis was associated with pollen-tube arrest in the style, as described for other Melastomataceae, but most self-incompatible species analysed showed pollen-tube growth to the ovary irrespective of pollination treatment. Apomictic species showed lower pollen viability and were less frequent among the Campo Rupestre plants. Among the New World species compiled, 43 were apomictic and 77 sexual (24 self-incompatible and 53 self-compatible). Most apomictic (86 ) and self-incompatible species (71 ) presented wide distributions, whilst restricted distributions predominate only among the self-compatible ones (53 ). Self-compatibility and dependence on biotic pollination were characteristic of Campo Rupestre and narrowly distributed New World Melastomataceae species, whilst apomictics are widely distributed. This is, to a certain extent, similar to the geographical parthenogenesis pattern of temperate apomictics.

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Plant mines are structures with the form of a cavity caused by consumption of host plant tissue by the insect's miner larvae. Plant mines are more common in leaves, but in Cipocereus minensis, a species in which the leaves are modified spines, the miner activity is restricted to the stem. The aim of this paper was to document the morphological and anatomical differences in the infected and uninfected stems of C. minensis due to the feeding habit of the mining agent. Fresh tissue samples of non-mined and mined young stem of C minensis were collected and examined in transverse sections. We hypothesize that the infection begins following mating when the females scratch the surface of the stem or while they feed on fruits and lay eggs, which subsequently develop into larvae, invading the cactus stem. The insect's miner larvae had mostly consumed the parenchyma tissue towards the center of the stem, and periderm formed along the entire path of the insect. This meristematic tissue or "wound periderm" is a common response for compartmentalization to isolate the damaged tissue, in this case the incubating chamber, in which the eggs will be placed. There were no signs of consumption of vascular tissue in the infested samples, further suggesting a compartmentalized infestation. The nest chamber was found in the stem pith region, with periderm surrounding an insect's miner pupa inside identified as a member of the Cerambycidae. The mining insect depends on a host plant to complete the life cycle; however, the nature of this partnership and the long-term effects of the insect on the plant tissue are unknown. The complex mechanisms by which herbivorous insects control the morphogenesis of the plant host are discussed. We propose that C. minensis has a recognition system to identify insect attack and evaluate the effectiveness of early response triggering compartmentalized defense mechanisms by protecting the injured area with a new layer of periderm.

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(Vertical distribution of biotic pollination systems in cerrado sensu stricto in the Triangulo Mineiro, MG, Brazil). Several factors can influence the distribution of floral resources and pollination systems in ecosystems, such as climate, altitude, geographic region, fragmentation of natural areas and differences in floristic composition along the vertical stratification. This study aimed to evaluate the distribution of the vertical stratification of biotic pollination systems in cerrado (sensu stricto) fragments in the Triangulo Mineiro. There was no significant difference (chi(2)(0.05,9)=14.17; P = 0.12) in total plant species richness among fragments, nor in the species richness of each layer (trees, shrubs, herbs and lianas) and the shrub layer was the best represented. Likewise, there was no significant difference between fragments for the systems of pollination (chi(2)(0 05,21) =13.80; P = 0.8778). Pollination by bees was the most common, corresponding to 85% of species in each fragment. In relative terms, plants pollinated by bees were dominant in all strata, reaching 100% for the lianas in fragments 1, 3 and 4 and for the herbs in fragments 1 and 4. In this study, based on floristic composition and distribution of biotic pollination systems in the vertical stratification, we could define a vertical mosaic in the cerrado studied, which has implications for the sustainability of communities in the cerrado, as well as the horizontal mosaic of vegetation types.

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The pressures for land use change have led to an increasing isolation of habitat remnants throughout the world. The goal of this study was to estimate the population size and density of some endemic and threatened species in a nature reserve in the Cerrado biome. One hundred and thirty four point transects were undertaken at the Estacao Ecologica de Itirapina (EEI), one of the last natural grassland savannah remnants in Sao Paulo state, in the south-east of Brazil between September and December 2006 and densities estimated for seven species (four endemic to the Cerrado, one near-endemic and two grassland specialists). Neither species reached the minimum viable population size of 500-5000 individuals. Four species, White-banded Tanager, White-rumped Tanager, Black-throated Saltator and Sharp-tailed Tyrant have populations ranging from 112 to 248 individuals, while the other species have a low population (< 60 individuals). The mean densities of Sharp-tailed Tyrant and Cock-tailed Tyrant in the EEI grassland showed similar values to those observed in larger areas of the Cerrado, which may indicate that the EEL grassland area is well conserved. In spite of the restricted size of the EEI, small areas can maintain some endemic and threatened bird populations, thus contributing to local biodiversity and the ecological processes in the region. The capacity of fragments of Cerrado (similar to 2,000 ha) to maintain populations of endemic and threatened bird species is unlikely to be effective in the long term.