914 resultados para algal morphology


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The purpose of this study was to assess the presence and the degree of expression of the molar tubercle according to sex, dentition and hemi-arches. Study casts of 126 patients were assessed, and those were under orthodontic treatment at the University of Franca, UNIFRAN; they were from both sexs, from 4 to 13 years old. The upper second primary molars and the upper first permanent molars, from both sides, were evaluated regarding the presence and the degree of expression of the molar tubercle. For an association study, the qui-square test was utilized. The concordance about the presence or absence of the molar tubercle according to dentition, hemi-arch and sex, was estimated by the Kappa Statistics. There was a sexual dimorphism concerning the presence/absence of the molar tubercle (p=0.009), however there was no significant association between the degree of expression of the tubercle and the sex (p=0.791). The molar tubercle was more frequently observed in the male sex, in upper second primary molars and in the form of depression. There was a significant and "moderate" concordance between the left and right sides in primary dentition (k=0.596), there was a "good" concordance in permanent dentition (k=0.708) and a "weak" and significant concordance between the presence of the molar tubercle and dentition (k=0.207).

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The adult female Culex quinquefasciatus midgut comprises a narrow anterior and a dilated posterior region, with epithelia composed of a monolayer of adjacent epithelial cells joined at the apical portion by septate junctions. Densely packed apical microvilli and an intricate basal labyrinth characterise each cell pole. Our morphological studies suggest that, during blood digestion, the anterior midgut region also participates in an initial absorptive stage which is probably related to the intake of water, salts and other small molecules. This activity peaked by 6 h after bloodmeal feeding (ABF) and ended approximately 18 h ABF, when the peritrophic membrane was already formed. After this time, absorption only occurred in the posterior region, with morphologic and biochemical evidence of high synthetic activity related to the secretion of proteases. Chymotrypsin, elastase, aminopeptidase, and trypsin reached their maximum activity at around 36 h ABF. Digestion products were apparently absorbed and transported to the basal labyrinth, from where they should be released to the hemolymph. At 72 h ABF, proteolysis had already ended and protein levels had returned to those observed before blood meal. The epithelium of the posterior region, however, did not return to its initial morphology, appearing quite disorganised. Additionally, from 48 h ABF onwards some epithelial cells showed morphological signals of apoptosis. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

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

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Miogryllus muranyi n. sp. is described from the Andean Acacia-Cactaceae semi-desert bush in the Chama Valley of Venezuela. The species is characterized by the unusual shape of the male head, which makes it readily distinguishable from any other congener known to date.

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

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The aim of the present work is to perform morphological and histological studies of the ovaries of workers and mated queens of Pachycondyla striata ants, which belong to the subfamily Ponerinae. The ovaries, after being removed, were schematized. Next, historesin and electronic scanning microscopy techniques were applied, making it possible to note that the left ovary owns a greater number of ovarioles when compared to the right one (workers - 7 to the right and 8 to the left; queens - 6 to the right and 7 to the left) and that the ovarioles of workers present a rather wrinkled aspect due to the fact that they are not developed. The same situation does not occur in mated queens once they always present oocytes in distinct development phases in their ovarioles. Histologically it was observed that the ovarioles are of the meroistic polytrophic kind. Inside the ovarioles of workers, germinative cells were observed in their distal portion, but their lumen were empty. on the other hand, ovarioles of mated queens presented the germinative cells as well as oocytes in different degrees of development, although more than one developing oocyte was never observed in the interior of each ovariole. It was possible to note the presence of follicular epithelium, chorion and vitellin membrane in oocytes of mated queens, which change morphologically according the oocyte development stage.

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The Dufour's gland is found closely associated with the sting apparatus of all female hymenopterans, playing multiple roles among bees. In some species of Bombus the gland may be involved in production of nestmate recognition pheromones, but in B. terrestris its function is not certain yet. The morphology of the :Dufour's gland of B. terrestris queens and the ultrastructural features of its cells were studied in different ages and behavioural stages using routine transmission electron microscopy. Measurements of the length and the diameter of the gland in the same conditions were also made. The Dufour's gland of the queen increases significantly in size (both in length and in diameter) with age and reproductive activity the ultrastructural features of the gland show electrondense material that comes from the haemolymph. This material is also present in the intercellular spaces, and is conducted to the subcuticular space, to be released directly into the glandular lumen. Hence at least part of the secretion is probably taken up directly from the haemolymph. The ultrastructural features indicate a more active phase of the gland corresponding to the period of egg-laying of the queen, and a decrease in activity when the queen is in hibernation as well as after the competition point. In conclusion, the gland is probably involved in reproduction, more specifically, in the marking off eggs.