810 resultados para Koch, Geoff


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Oocyte maturation in the thelytokous parthenogenetic tick Amblyomma rotundatum was examined for the first time using light and scanning electron microscopy. The panoistic ovary lacks nurse and follicular cells and is a single continuous tubular structure forming a lumen delimited by the ovarian wall. Oocytes of tick species are usually classified according to cytoplasm appearance, the presence of germinal vesicle, the presence of yolk granules, and the chorion. However, for this species, we also use oocyte size as an auxiliary tool since most oocytes were in stages I-Ill and were histologically very similar. Oocytes were classified into five development stages, and specific characteristics were observed: mature oocytes with thin chorion, pedicel cells arranged forming an epithelium with two Or more oocytes attached by the same structure, and a large number of oocytes in the process of reabsorption. (C) 2011 Elsevier GmbH. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A reassessment of the taxonomic status of Amblyomma cajennense based on the morphological analyses of ticks from the whole distribution area of the species resulted in the redescription of A. cajennense, the validation of 2 species which had been reduced to synonymy in the past, Amblyomma mixtum and Amblyomma sculptum, and the description and definition of 3 new species, Amblyomma tonelliae n. sp., Amblyomma interandinum n. sp., and Amblyomma patinoi n. sp. This study provides descriptions and redescriptions, scanning electron microscopic and stereomicroscopic images, updated synonymies, information on geographical distributions, and host associations for each of the 6 species. Amblyomma cajennense s.s. is found in the Amazonian region of South America, A. interandinum is reported from the northern part of the Inter-Andean valley of Peru, A. mixtum is present from Texas (U.S.A.) to western Ecuador, A. patinoi occurs in the Eastern Cordillera of Colombia, A. tonelliae is associated with the dry areas of the Chaco region which spans from central-northern Argentina to Bolivia and Paraguay, whereas A. sculptum is distributed from the humid areas of northern Argentina, to the contiguous regions of Bolivia and Paraguay and the coastal and central-western states of Brazil.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Scan von Monochrom-Mikroform

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Chajim Soutine

Relevância:

20.00% 20.00%

Publicador:

Resumo:

J. Goeschke

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Vom Professor Dr. Karl Koch

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Vom Professor Dr. Karl Koch

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Vom Professor Dr. Karl Koch

Relevância:

20.00% 20.00%

Publicador:

Resumo:

anonym