The intramandibular gland of leaf-cutting ants (Atta sexdens rubropilosa Forel 1908)

The eusociality developed in Hymenoptera and Isoptera is driven by an efficient interaction between exocrine glands and jointed appendages, both in close interaction with the environment. In this context, the mandible of ants plays an important role, since, in addition to being the main jointed appendage, it possess glandular functions. As an example we might name the two glands associated with the mandible: the mandibular and the intramandibular glands. The intramandibular gland is found inside the mandible and consists of a hypertrophied secretory epithelium and secretory cells in the mandible's lumen. The secretion of the secretory epithelium is liberated through intracuticular ducts that open at the base of hairs at the mandible's surface. The secretion of the intramandibular gland (epithelium and secretory cells) reacted positively to tests for the detection of polysaccharides and proteins, thus suggesting that it consists of glycoproteins. The ultrastructure of the secretor epithelium presents variations related to the developmental stage of the individual, showing a large number of ribosomes and microvilli close to the cuticle in young individuals, while in the older specimens it was possible to note the formation of ail intracellular reservoir. These variations of secretory epithelium, as also the interaction between the cellular groups inside the mandible, are important information about this gland in leaf-cutting ants. (c) 2005 Elsevier Ltd. All rights reserved.

Lipid distribution in salivary glands of larvae and adult bees (Hymenoptera : Apidae)

Cytochemical studies were carried out to establish lipid distribution in the salivary glands of larvae and adult bees, using the imidazole buffer technique. In the duct cells of the larval salivary gland, the reaction was positive in the epicuticle and negative in the glandular lumen. The absence of smooth endoplasmic reticulum and the presence of lipids in the intercellular space suggest that lipids absorbed from the haemolymph could be used in the constitution of the epicuticle, after having been conveyed through the epithelium. In adult workers (new-emerged, nurse and forager workers), the head salivary glands presented a positive reaction in the secretion in glandular lumen, identifying its lipidic nature.

Morphological characterization of the ovary and oocytes vitellogenesis of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari : Ixodidae)

This study presents the morphology of the ovary, as well as the process of the vitellogenesis in oocytes of the tick Rhipicephalus sanguineus. 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 wall formed by small epithelial cells with rounded nuclei which delimit the lumen. The oocytes in the different developmental stages in this tick species were classified into five stages (I V). They remain attached to the ovary during vitellogenesis by a cellular pedicel and afterwards the mature oocytes (stage V) are released into the ovary lumen. (c) 2005 Elsevier B.V. All rights reserved.

Programmed cell death in the larval salivary glands of Apis mellifera (Hymenoptera, Apidae)

The morphological and histochemical features of degeneration in honeybee (Apis mellifera) salivary glands were investigated in 5th instar larvae and in the pre-pupal period. The distribution and activity patterns of acid phosphatase enzyme were also analysed. As a routine, the larval salivary glands were fixed and processed for light microscopy and transmission electron microscopy. Tissue sections were subsequently stained with haematoxylin-eosin, bromophenol blue, silver, or a variant of the critical electrolyte concentration (CEC) method. Ultrathin sections were contrasted with uranyl acetate and lead citrate. Glands were processed for the histochemical and cytochemical localization of acid phosphatase, as well as biochemical assay to detect its activity pattern. Acid phosphatase activity was histochemically detected in all the salivary glands analysed. The cytochemical results showed acid phosphatase in vesicles, Golgi apparatus and lysosomes during the secretory phase and, additionally, in autophagic structures and luminal secretion during the degenerative phase. These findings were in agreement with the biochemical assay. At the end of the 5th instar, the glandular cells had a vacuolated cytoplasm and pyknotic nuclei, and epithelial cells were shed into the glandular lumen. The transition phase from the 5th instar to the pre-pupal period was characterized by intense vacuolation of the basal cytoplasm and release of parts of the cytoplasm into the lumen by apical blebbing; these blebs contained cytoplasmic RNA, rough endoplasmic reticule and, occasionally, nuclear material. In the pre-pupal phase, the glandular epithelium showed progressive degeneration so that at the end of this phase only nuclei and remnants of the cytoplasm were observed. The nuclei were pyknotic, with peripheral chromatin and blebs. The gland remained in the haemolymph and was recycled during metamorphosis. The programmed cell death in this gland represented a morphological form intermediate between apoptosis and autophagy.

Cephalic salivary glands of two species of advanced eusocial bees (Hymenoptera: Apidae): morphology and secretion

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ocorrência, morfologia e ultra-estrutura da glândula de Dufour de Scaptotrigona postica Latreille (Hymenoptera: Apidae)

A glândula de Dufour é uma glândula acessória do aparelho reprodutivo feminino das abelhas. Nas abelhas neotropicais sem ferrão, tem sido pouca estudada sob todos os aspectos: morfológico, ontogenético e bioquímico. Na tentativa de colaborar com o conhecimento dessa glândula em abelhas sem ferrão, foi realizado um estudo da sua ocorrência, morfologia e desenvolvimento em Scaptotrigona postica Latreille. Os resultados mostraram que ela se encontra ausente nas operárias, como ocorre em muitas outras espécies desse grupo. Nas rainhas, as células glandulares parecem mais ativas nas virgens, possuindo uma desenvolvida rede de retículo endoplasmático liso tubular, grânulos de secreção e polirribossomos dispersos no citoplasma, além de apresentarem núcleos maiores do que os das células glandulares das fisogástricas. Nas rainhas fisogástricas há dois tipos de células glandulares, ambas aparentemente inativas sinteticamente. As glândulas das rainhas fisogástricas são claramente capazes de captar substâncias da hemolinfa, provavelmente lipídios, que não penetram nas células, mas passam pelos espaços intercelulares e, através da cutícula, chegam diretamente à luz da glândula. A bem desenvolvida dupla camada de lâmina basal ao redor da glândula pode atuar no processo de captação de substâncias da hemolinfa. A secreção, e conseqüentemente sua função, pode ser diferente nas duas classes de rainhas.

Occurrence, morphology and ultrastructure of the Dufour gland in Melipona bicolor Lepeletier (Hymenoptera, Meliponini)

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

Effects of fipronil (active ingredient of Frontline (R)) on salivary gland cells of Rhipicephalus sanguineus females (Latreille, 1806) (Acari: Ixodidae)

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

Ovary and oocyte maturation of the tick Amblyomma brasiliense Aragao, 1908 (Acari: Ixodidae)

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

Morphological characterization of the nymphs rhipicephalus sanguineus ticks (Latreille, 1806) (Acari: Ixodidae). Description of the testes, integument, malpighian tubules, and midgut on the detachment day

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

Cephalic salivary gland ultrastructure of worker and queen eusocial bees (Hymenoptera, Apidae)

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

Morphological records of oocyte maturation in the parthenogenetic tick Amblyomma rotundatum Koch, 1844 (Acari: Ixodidae)

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

Ultrastructure of the mature testicular vesicle of Pseudonannolene tocaiensis Fontanetti, 1996 (Diplopoda, Pseudonannolenidae)

The mature testicular vesicles of the species Pseudonannolene tocaiensis have three portions: a peripheral portion; a central portion that is typically secretory and between these two an intermediary portion, a lumen filled with spermatozoa. Both secretory and peripheral portions present the same type of cells. The ultrastructural analysis of the peripheral portion suggests it is involved in hormone synthesis. The secretory portion probably contributes to the production of spermatic fluid, compensating for the absence of male accessory glands in this species. (c) 2007 Elsevier Ltd. All rights reserved.

Silk formation mechanisms in the larval salivary glands of Apis mellifera (Hymenoptera : Apidae)

The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th instar and finishes at the end of the same instar. This process begins in the distal secretory portion of the gland, going towards the proximal secretory portion; and from the periphery to the center of the gland lumen. The silk proteins are released from the secretory cells as a homogeneous substance that polymerizes in the lumen to form compact birefringent tactoids. Secondly, the water absorption from the lumen secretion, carried out by secretory and duct cells, promotes aggregation of the tactoids that form a spiral-shape filament with a zigzag pattern. This pattern is also the results of the silk compression in the gland lumen and represents a high concentration of macromolecularly well-oriented silk proteins.

A comparative cytochemical study of the dufour gland in the eusocial bee Apis mellifera Linne, 1758 and Melipona bicolor Lepeletier, 1836

Dufour glands of Apis mellifera and Melipona bicolor were studied under light and transmission electron microscopy, using the cytochemical techniques of mercury bromophenol blue for protein detection, imidazole-buffered osmium tetroxide selective staining of unsaturated lipids, lanthanum nitrate for intercellular junction identification and zinc-iodide-osmium tetroxide for cytoplasmic endomembrane visualization. The results in both species corroborated the lipid nature of the gland secretion and showed in A. mellifera the poverty of the synthetic machinery in the worker gland cells in comparison with the queen, as expected by previous biochemical analyses. The pathway of the exogenous compounds of the secretion is intracellular, since substances can penetrate the cell folds and intercellular junctions, but their access to the, gland lumen is barred by the apical intercellular junctions.