Giardia muris and Giardia duodenalis groups: ultrastructural differences between the trophozoites

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

The dawn of animal skeletogenesis: Ultrastructural analysis of the Ediacaran metazoan Corumbella werneri

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Changes in the morphology and ultrastructure of the Dufour's gland during the life cycle of the bumble bee queen, Bombus terrestris L-(Hymenoptera : Bombini)

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.

Morphological, histological, and ultrastructural characterization of degenerating salivary glands in females of the cattle-tick Rhipicephalus (Boophilus) microplus (CANESTRINI, 1887) (Acari : Ixodidae)

The present study describes the morphology and ultrastructure of the salivary glands of semi-engorged females of the southern cattle-tick Rhipicephalus (Boophilus) microplus. The acini that compose these glands, at that specific feeding stage, show cells featuring degenerative process of the salivary glands, such as: vacuolated cytoplasm, condensed chromatin, fragmented nuclei, and presence of apoptotic bodies. In addition, the presence of microorganisms was detected, with morphology typical of protozoa, inside these organs. (c) 2005 Elsevier Ltd. All rights reserved.

Morphological, histological, and ultrastructural studies of the ovary of the cattle-tick Boophilus microplus (Canestrini, 1887) (Acari : Ixodidae)

This study presents the morphology of the ovary, as well as the dynamics of the vitellogenesis process in oocytes of the cattle-tick Boophilus microplus. The ovary of these individuals is of the panoistic type; therefore, it lacks nurse cells. This organ consists of a single tubular structure, continuous, and composed of a lumen delimitated by a wall of small epithelial cells with rounded nuclei. In this tick species, the oocytes were classified into six stages varying from I to VI and according to: cytoplasm appearance and presence of the germ vesicle, yolk granules, and chorion. Oocytes of various sizes and at different developmental stages remain attached to the ovary through a cellular pedicel until completing stage V. Afterwards, they are liberated into the lumen and from there to the exterior. Some oocytes (classified as type VI) showed an atypical appearance indicating that some of the cellular components would be undergoing a degenerative process and/or reabsorption. (c) 2004 Elsevier B.V. All rights reserved.

Venom gland of Pachycondyla striata worker ants (Hymenoptera : Ponerinae). Ultrastructural characterization

Morphological data concerning the venom gland of worker ants of Pachycondyla striata revealed that this gland consists of three distinct regions: an external secretory portion, composed by a secretory filament that bifurcates in order to give rise to other two filaments; an internal secretory portion, represented by the convoluted gland; and a storage portion, represented by a sac-shaped reservoir. The ultrastructural analysis showed that the reservoir is enveloped by a simple pavementous epithelium, coated internally with a cuticle. The external secretory portion is composed by cells forming a simple cubic epithelium, in which the apical portion presents numerous microvilli while the basal portion of the cells shows infoldings of the plasma membrane containing numerous mitochondria. The convoluted gland possesses cells of irregular morphology with nuclei containing condensed chromatin, suggesting inactivity. However, these cells are in fact undergoing secretory activity, which is probably added to the final secretion produced by the gland. The cytoplasm of these cells contains several elements distributed therein, such as ribosomes and polyribosomes, lipid droplets, and protein inclusions in the form of crystals, thus Suggestive of protein storage, which would be used by the insect when metabolically required. (c) 2005 Elsevier Ltd. All rights reserved.

Ultrastructural features of the fat body and oenocytes of Rhinocricus padbergi Verhoeff (Diplopoda, Spirobolida)

The fat body of the diplopod Rhinocricus padbergi is located in two preferential areas of its body: a) immediately below the tegument, denominated parietal, and b) filling the body cavity, close to the viscera, mainly the ovaries and alimentary canal, denominated perivisceral.Ultrastructurally, its cells, the adipocytes, presented varied morphology and contained organelles indicating that they are cells that mainly produce and store lipids and proteins. The presence of cells similar to the oenocytes found in insects was observed for the first time in diplopods, associated to the fat body of R. padbergi. Our observations suggest that this tissue probably maintains activity cycles, since the presence of cells undergoing apoptosis was detected.

A morpho-histological and ultrastructural study of the mandibular glands of Atta sexdens worker ants (Hymenoptera : Formicidae)

We describe here the morphology, histology and ultrastructure of the mandibular glands of Atta sexdens (Hymenoptera: Formicidae) worker ants. The mandibular glands consist of a reservoir with an excretory duct and a secretory portion linked to the reservoir trough canaliculi. These glands have the same morphology in the three castes studied, differing only in size, with smaller glands observed in minima workers and larger glands in soldiers.

Ultrastructural study of the salivary glands of the sugarcane spittlebug Mahanarva fimbriolata (Stal, 1854) (Euhemiptera : Cercopidae)

Spittlebugs are insects that suck sap from plants and regurgitate saliva containing toxic enzymes into the leaves. As a consequence, the conductive channels are blocked resulting in dry leaves, thus giving a burned aspect to the plantation. This work performed ultrastructural analyses of the salivary glands of the sugarcane spittlebug Mahanarva fimbriolata, since these organs produce the enzymes that are injected into the plants, thus being responsible for the economic losses in the production of sugarcane. Three kinds of secretory cells are found in principal gland, forming the lobules I-IV. The main differences among these cells relate to size, morphology and electron density of the secretory vesicles. The accessory glands contain different secretory vesicles to those in the principal gland. Muscular cells are found around the entire gland. The different secretory vesicles found in both principal and accessory glands indicate that the gland produces different substances or that the secretion in the interior of cells passes through a maturation process. (c) 2005 Elsevier Ltd. All rights reserved.

Occurrence and ultrastructural characterization of nuage during oogenesis and early spermatogenesis of Piaractus mesopotamicus Holmberg, 1887 (Teleostei)

Foi investigada a ocorrência e caracterizada ultra-estruturalmente a eliminação de material nuclear eletrondenso (nuage) para o citoplasma durante a ovogênese e durante os estágios iniciais da espermatogênese de Piaractus mesopotamicus, um peixe do Pantanal Matogrossense de ciclo reprodutivo sazonal. Constataram-se nas células germinativas femininas dois momentos de eliminação desse material, na ovogônia e no ovócito em fase perinucleolar. Nas células masculinas, material com morfologia e comportamento muito semelhante foi encontrado na espermatogônia. em todos os casos, o material associou-se a mitocôndrias. A possível função desse material foi discutida.

Ultrastructural characterization of CD133(+) stem cells bound to superparamagnetic nanoparticles: possible biotechnological applications

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

Morphology and protein content of hepatocytes in type I diabetic rats submitted to physical exercises

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ultrastructural studies of the mandibular gland of Melipona quadrifasciata Lepeletier, 1836 (Apidae, Meliponini): a comparison between workers and queens

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

Ultrastructural analysis of the effect of mating delay on cell death in the ovaries of virgin honey bee (Apis mellifera L.) queens

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

Ultrastructural analysis of the fat body in workers of Attini ants (Hymenoptera: Formicidae)

In the present study a comparative morphological analysis of the fat body cells of ant workers of the basal Attini species Cyphomyrmex rimosus and Mycetarotesparallelus, and the derived species Acromynnex disciger and Atta laevigata was conducted. The results revealed that the fat body is located mainly in the abdomen around organs (perivisceral) and near the integument (parietal). The main cells observed are spherical or polygonal trophocytes with a slightly rough surface. The oenocytes, another cell type found, are closely associated with trophocytes, and present a spherical or polygonal shape and a smoother surface. The morphometric analysis showed that the area of trophocytes and oenocytes of C rimosus and M parallelus is significantly smaller when compared to those of A. disciger and A. laevigata. In the cytoplasm of parietal and perivisceral trophocytes and oenocytes, electronlucent droplets (probably lipids) and electrondense granules (probably proteins) indicate the participation of these cells in the storage of these elements, while digestive vacuoles, residual bodies, and multivesicular bodies suggest a role in intracellular digestion. In perivisceral trophocytes and oenocytes of C rimosus, the presence of mitochondria, lamellar rough endoplasmic reticulum, and Golgi complex suggests that these cells synthesize proteins. Based on these data, no significant differences were observed between the fat body cells of basal and derived ants, except regarding the larger size of trophocytes and oenocytes of the derived species A. disciger and A. laevigata. (C) Koninklijke Brill NV, Leiden, 2009