6 resultados para Tonality

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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As criteria in photointerpretation slope features, tonality, texture, structure, vegetation density and gullies were utilized. The origin of the surficial formations is related to the weathering, erosion and deposition processes and little diagenesis.-after English summary

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Toluidine Blue dye containing increasing concentrations of Mg2+ or Ca2+ can show loss of metachromacy at a certain concentration of the inorganic cation when staining DNA-protein complexes in vitro and in vivo. This process has been named Critical Electrolyte Concentration (CEC) and is applied to the study of protein-nucleic acid complexes at different stages of chromatin supra-organization. Male gametocytes of the species Pseudonannolene tocaiensis were studied, observing a large amount of ribonucleoproteins in the gametocytes cytoplasm throughout prophase I. The nucleolus is maintained during most of the prophase. The highly condensed region showing the bouquet formation appeared stained with the typical tonality for chromatin; this region corresponds to the constitutive heterochromatin. We also observed the presence of RNA all through the chromosomes in prophase I. The permanence of this material surrounding the chromosomes during male meiosis is difficult to explain, since a great reduction of the products of spermatogenesis occurs due to the fact that most of the material of the spermatozoids is not used during fecundation. However, in P. tocaiensis this material is remains even at the spermatids. It is known that during the spermiogenesis of certain insects, RNA synthesis continues at the spermatid, being subsequently eliminated from the nucleus and then from the cell due to the elongation of the nucleus. Therefore, we could suggest that permanence of this material (RNA) during meiosis has a function in the process of cell division.

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Phylogenetic approaches based on mitochondrial DNA variation (fragments of Cyt B and 16S ribosomal RNA) have revealed Triatoma sherlocki as the most recent species addition to the Triatoma brasiliensis species complex; a monophyletic group which includes T. brasiliensis, Triatoma melanica, and Triatoma juazeirensis. T. sherlocki is the most differentiated among all species of this complex: it is unable to fly, possesses longer legs than the other members, and has reddish tonality in some parts of its exochorion. We question whether these species are reproductively compatible because of this pronounced morphological differentiation, and therefore, we present a series of cross breeding experiments that test compatibility between T. sherlocki and other members of the T. brasiliensis complex. We extended our analyses to include crosses between T. sherlocki and Triatoma lenti, because the latter has been suggested as a possible member of this complex. T. sherlocki male. ×. T. lenti female pairs failed to produce hybrids. All other crosses of T. sherlocki and members of T. brasiliensis species complex, as well as backcrosses, produced viable offspring through the third generation. This study stresses the importance of searching for the features that may isolate members of the T. brasiliensis species complex. © 2013 Elsevier B.V.

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

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)