Ultrastructure of the ducts of the reproductive tract of males of Melipona bicolor bicolor Lepeletier (Hymenoptera, Apinae, Meliponini)

The present paper describes the ultrastructural features of seminal vesicle, post-vesicular vas deferens and ejaculatory duct of Melipona bicolor bicolor from newly emerged and mature males. Although the results do not show very consistent morphological signs of secretory activity by the epithelium of these organs, lipidic droplets and lamellar granules present in mature males' seminal vesicles and the vacuoles present in post-vesicular vas deferens are probably secretion. Besides, the spermatozoa in the lumen are immersed in a material of characteristic structure, which must be produced in superior regions of the reproductive system of immature males, not studied here. The presence of sperm cells, apparently in cytoplasm vesicles of seminal vesicle and post-vesicular vas deferens, suggests spermiophagy by their epithelium.

Ultrastructural studies of the mandibular glands of the minima, media and soldier ants of Atta sexdens rubropilosa (Forel 1908)

The mandibular glands of Hymenoptera are structures associated with the mandibles and constitute part of the salivary glands system. Histological studies in workers of Atta sexdens rubropilosa revealed that this gland contains two portions: a secretory and a storage portion or reservoir. Both portions are connected by means of canaliculi. The object of the present work was the study of the ultratructure of the mandibular glands of minima, media and soldier ant of A. s. rubropilosa by TEM techniques. The glands, in the three castes studied, possess a reservoir, constituted by a simple pavementous epithelium surrounded by the cuticular intima and the secretory portion is constituted by cells of rounded shape. The secretory cells, mainly of minima and soldier, were rich in smooth endoplasmic reticulum. The media worker and soldier presented a large number of mitochondria, of varying shape. Well-developed Golgi complexes were also present in the soldiers. The secretory cells in minima, media and soldier were provided with collecting intracellular canaliculi, which were linked to the reservoir through the extracellular portion. The cytoplasm of the canaliculi-forming cell was poor in organelles. In the individuals of the three castes of A. s. rubropilosa, the presence of lipid secretion granules suggested, beyond the other functions, also a possible pheromonal action. The different roles executed by the different insect castes are directly dependent on the glandular products and, consequently, on the secretory cellular characteristics. (c) 2005 Elsevier Ltd. All rights reserved.

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.

Comparative study of the ultrastructure and secretory dynamic of hypopharyngeal glands in queens, workers and males of Sceptotrigona postica latreille (Hymenoptera, Apinae, Meliponini)

The secretory cycle of hypopharyngeal glands (HPGs) in Scaptotrigona postica resembles that of Apis mellifera: in newly emerged workers the HPGs are in prefunctional state, their maximum development happens in the nurse workers and in forager workers they show signs of reabsorption. In S. postica these glands are also present in queens and males where they are more developed in newly emerged individuals. The ultrastructural features of the HPG secretory cycle in workers of S. postica and A. mellifera are alike: granular endoplasmic reticulum well developed, large secretion masses around the intracellular canaliculus in nurse workers and extensive degenerative structures in forager workers. Then it is suggested that the HPG secrete similar substances in both species. A second secretory cycle seems to occur in early foragers, may be with production of enzymes. The role of the HPGs in queens and males remains unknown but one possibility is enzyme production.

Ultrastructure of last larval instar fat body cells of Pachycondyla (= Neoponera) villosa (Formicidae : Ponerinae): cytochemical and chemical analysis

The ultrastructure of the fat body cells (trophocytes) of the last larval instar of Pachycondyla (= Neoponera) villosa is presented. The cytoplasm is restricted to the cell periphery and to the smaller strips among the vacuoles, protein granules, lipid droplets, and around the nucleus. Cytochemically, the presence of basic amino acids in the protein granules and in the nuclei was observed by using the ethanolic phosphotungstic acid technique (EPTA). The lipid droplets stained for unsaturated lipids. This result was further confirmed by gas chromatography and mass spectrometry, where the unsaturated fatty acids were identified as oleic and linoleic acids together with saturated fatty acids such as palmitic and stearic acid. Carbohydrates (glycogen) were also detected in the fat body. The glycogen is present as beta particles distributed among the lipid droplets and sometimes attached to them.

Alterations induced by the juvenile hormone in glandular cells of the Apis mellifera venom gland: Applications on newly emerged workers (Hymenoptera, Apidae)

Histological and histochemical analyses were carried out in order to evaluate the influence of the topical application of a synthetic juvenile hormone on the secretory cycle and degeneration of the venom gland of Apis mellifera. Newly emerged workers received the topical application of synthetic hormone and the results were compared to the normal development of the secretory cycle in virgin and mated queens. The first worker group received the juvenile hormone diluted in hexane (2 mu g/mu L), the second received only mu L of hexane, and the third did not receive any kind of application. After the application the workers were returned to the colony and collected at the ages of 14 and 25 days of adult life. The groups with virgin queens and the other with mated queens, did not receive the treatment. The results show that the individuals treated with juvenile hormone and with pure hexane presented differences in the histological and cytochemical aspects of the secretory cells of the venom gland. The data indicate that both the juvenile hormone and hexane accelerate the activity of the secretory cycle and the degeneration of the venom gland; however, the juvenile hormone proved to be more effective than hexane. (c) 2006 Elsevier Ltd. All rights reserved.

Morphology of the sternal gland in workers of Coptotermes gestroi (Isoptera, Rhinotermitidae)

The sternal gland is considered the only source of trail pheromones in termites. The morphology of the sternal gland was investigated in workers of Coptotermes gestroi using transmission and scanning electron microscopy. The results showed a small bilobed gland at the anterior part of the fifth abdominal sternite. The cuticular surface of the sternal gland showed a V-shaped structure with two peg sensilla in elevated socket and various campaniform sensilla. Pores and cuticular scale-like protuberances also occur in the glandular area. The ultrastructure showed a gland composed of class I cells and two different types of class 3 cells distinguished by location, different size and electron-density of secretory vesicles. Small class 3 cells (type 1) of the anterior lobe are inserted among class I cells and have weakly electron-dense vesicles associated with mitochondria, glycogen and smooth endoplasmic reticulum. The class 3 cells (type 2) of posterior lobe showed many round electron-lucent vesicles of secretion, abundant free ribosomes and a well-developed Golgi apparatus. Each class 3 cell is connected to the cuticle by a cuticular duct constituted by the receiving canal and the conducting canal. The secretion of class I cells is stored in an inner subcuticular reservoir that is delimited by the microvilli of these cells. This inner reservoir is large and crossed by the campaniform sensilla and ducts of two types of class 3 cells that open outside of the insect body. An exterior reservoir also is present between the fourth and fifth sternite. The complex structure of the sternal gland suggests multicomponents for the trail pheromone in the worker of C gestroi. (c) 2005 Elsevier Ltd. All rights reserved.

Phylogeny, ultrastructure, histopathology and prevalence of Myxobolus oliveirai sp. nov., a parasite of Brycon hilarii (Characidae) in the Pantanal wetland, Brazil

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

General morphology and ultrastructure of the venom apparatus and convoluted gland of the fire ant, Solenopsis saevissima

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

Ultrastructure features of the midgut of the female adult Amblyomma cajennense ticks Fabricius, 1787 (Acari: Ixodidae) in several feeding stages and subjected to three infestations

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

The midgut of Cephalotes ants (Formicidae: Myrmicinae): Ultrastructure of the epithelium and symbiotic bacteria

The ultrastructural analysis of the midgut of Cephalotes atratus. C. clypeatus, and C. pusillus reveled that the midgut epithelium lays on a basal lamina and is composed basically of three cell types: digestive cells, regenerative cells, and goblet cells. In these ants, the rough endoplasmic reticulum, in addition to producing digestive enzymes, is involved in the formation of concretions and ion storage in specialized vacuoles present in the midgut. These concretions are spherocrystals and may contribute to stabilize the pH and to maintain symbiotic bacteria found between microvilli. The ultrastructure analysis of these bacteria revealed the presence of a double envelope typical of gram-negative bacteria. For the three species examined, the ultrastructure similarities are conspicuous, suggesting that this may be the pattern for the genus Cephalotes. Details of the relationship between bacteria and microvilli were examined. (C) 2010 Elsevier Ltd. All rights reserved.

MRT Letter: A Novel Tegumental Gland in Female Imagoes of the Neotropical Termite Cornitermes cumulans (Isoptera, Termitidae, Syntermitinae)

In general, the exocrine glands of social insects are structures involved in the chemical communication associated with social life. Here, we report the discovery of an unknown tegumental gland that is present in the female imagoes of Cornitermes cumulans and occurs next to the well-developed tergal glands that have previously been described. The tegumental glands release their secretion in the intersegmental membrane and are composed of bicellular units, a secretory cell and a canal cell, that are closely located to the epidermal cells in the inferior part of the eighth and ninth tergites. The ultrastructure of the glandular cells showed abundant smooth endoplasmic reticulum, suggesting that the secretion may be pheromonal, although its function is still unknown. These exocrine structures are facing the tergal glands, and we hypothesized that they act synergistically with the tergal glands to generate short-range attraction during tandem behavior. Microsc. Res. Tech. 73: 1005-1008, 2010. (C) 2010 Wiley-Liss, Inc.

Ovarian ultrastructure in virgin queens of Apis mellifera L. narcotized by CO2

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)

Permethrin-induced ultrastructural changes in oocytes of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged females

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