247 resultados para GENUS ACANTHAMOEBA


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The species belonging to the subfamily Phyllomedusinae presents physiological and behavioral adaptations to economise water such as secretion of lipids coupled with its spreading onto the skin surface through a complex behavior, adoption of diurnal torpor and secretion of uric acid. Here we describe other adaptation probably involved with water economy, registered in Phyllomedusa distincta, P. tarsius, P. tetraploidea and natural hybrids of P. distincta and P. tetraploidea - at dusk, these amphibians perform an elaborate moulting behavior that encompasses the cleaning of the body with the limbs plus gaping and body contractions. Our data show the daily moulting in P. distincta and suggest that the same mechanism occurs for the other species studied. We suppose that daily moulting improves the skin permeability to water being a characteristic of the phyllomedusines which spread lipids onto the skin surface.

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A systematic re-evaluation of Vampyressa pusilla warrants the elevation of V. p. thyone from subspecies to species rank based on its distinction from the allopatric V. p. pusilla. Morphological, mensural, chromosomal, and mitochondrial differences define each of these two taxa as divergent lineages. Vampyressa pusilla is endemic to the Atlantic Forest of southeastern South America and V. thyone is found allopatrically in northwestern South America, Central America, and southern Mexico. A molecular phylogenetic analysis of the mtDNA ND3-4 gene region using restriction endonuclease cut sites resulted in a monophyletic, although weakly supported Vampyressa ingroup with Chiroderma, and a clade of Mesophylla and Ectophylla as successive basal outgroup lineages. The phylogeny within Vampyressa, with the exception of V. melissa which is most similar to V. thyone based on karyotypes and morphology, had a topology of ((pusilla + thyone) + ((brocki + nymphaea) + bidens))).

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Multivariate morphometrics and image analysis were used to determine the number of well-delineated infrageneric taxa of Sirodotia in North America. Three groupings were distinguished from 25 populations examined from Newfoundland and Quebec in the north to central Mexico in the south. These groupings were statistically related to 10 type specimens, and the following species were recognized: Sirodotia huillensis (Welwitsch ex W. et G. S. West) Skuja (syn. S. ateleia Skuja), S. suecica Kylin (syn. S. acuminata Skuja ex Flint and S. fennica Skuja), and S. tenuissima (Collins) Skuja ex Flint. These species are differentiated on the basis of whorl shape and degree of separation at maturity (S. suecica, rounded and appressed; S. huillensis and S. tenuissima, truncated apex and separated), the density of spermatangia (S. huillensis, dense clusters, S. suecica and S. tenuissima, sparsely aggregated), and the mode of germination of the gonimoblast initial (S. suecica and S. tenuissima,from the nonprotuberant side of the fertilized carpogonium; S. huillensis from the protuberant side). Sirodotia huillensis was found only in the desert-chaparral, whereas S. suecica and S. tenuissima occurred from south-temperate to boreal regions in cool (temperature 8-18-degrees-C), low ion (specific conductance 10-99 muS.cm-1), and mildly acidic to neutral (pH 5.7-7.3) waters.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We describe the karyotype of Thalpomys species, from different Brazilian localities of the Cerrado. Thalpomys cerradensis Herskovitz, 1990 showed 2n = 36, FN = 34 and T. lasiotis Thomas, 1916 2n = 38, FN = 38. Comparisons of G-band karyotypes showed evident inter-specific homologies indicating that their chromosome complements could be derived from one another by two presumed rearrangements. Both species showed pericentromeric C-band regions in almost all chromosomes but a comparison with CMA3/DA/DAPI staining indicated that the molecular content of heterochromatic regions was different. T. lasiotis specimens from two different localities differed in the morphology of the X chromosome due to the presence of a short heterochromatic arm. These chromosome types are apparently fixed in each population rather than maintained as a polymorphic variation. Phylogenetic analyses supported the monophyly of the genus Thalpomys but was not capable of elucidating its phylogenetic relationship to other Akodontini rodents. These analyses also showed inter-individual variation in T. lasiotis, even within a given population. Phylogenetic analyses placed T. lasiotis specimens with different karyotypes in different monophyletic branches. Molecular and karyologic data confirmed the identity of the genus Thalpomys.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This review aimed to show the importance of Strelitzia in Floriculture. The genus named after the duchy of Mecklenburg-Strelitz, birthplace of Queen Charlotte of United Kingdom. A commom name of the genus is bird of paradise flower, because of a supposed resemblance of its flowers to the bird of paradise. In this context, it is currently a growing interest in exotic cultures, with tropical characteristics, such as species of the family Strelitziaceae. Thus, it was observed that the production of agricultural activity, Strelitzia is one of increasing social and economic importance in the world.