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.

Amblyomma triste (Koch, 1844) (Acari : Ixodidae) Ovaries: An ultrastructural analysis

This study presents an ultrastructural analysis of the ovary of the tick, Amblyomma triste. The ovary of this species is of the panoistic type that is, without nursing and follicular cells. It is composed of a layer of epithelial cells forming a wall and of germinative cells that generate the oocytes which remain attached to the external margin of this wall by a multicellular pedicel. The different developmental stages in the oocytes had been described by Oliveira et al. [Oliveira, P.R., Bechara, G.H., Camargo-Mathias, M.I., 2006. Amblyomma triste (Koch, 1844) (Acari: Ixodidae): Morphological description of the ovary and of vitellogenesis. Experimental Parasitology 113, 179-185]. The results of the investigation suggest that besides exogenous production of vitellogenic elements, endogenous production can take place simultaneously, contributing to the development and growth of the oocytes. (c) 2007 Elsevier B.V. All rights reserved.

Ultrastructural detection of proteins, lipids and carbohydrates in oocytes of Amblyomma triste (Koch, 1844) (Acari; Ixodidae) during the vitellogenesis process

The ovary of the tick Ainblyomma triste is classified as panoistic, which is characterized by the presence of oogonia without nurse and follicular cells. The present study has demonstrated that the oocytes in all developmental stages (I-IV) are attached to the ovary through a pedicel, a cellular structure that synthesizes and provides carbohydrate, lipids and proteins supplies for the oocytes during the vitellogenesis process. The lipids are deposited during all oocyte stages; they are freely distributed as observed in stages II, III and IV or they form complexes with other elements. The proteins are also deposited in all stages of the oocytes, however, in lower concentration in the stage IV. There is carbohydrate deposition from oocytes in the stage II as well as in stages III and IV. In addition, the present work has demonstrated that the oocyte yolk of A. triste has a glycolipoprotein nature and the elements are deposited in the following sequence: firstly the lipids and proteins, and finally the carbohydrates. (c) 2007 Elsevier Ltd. All rights reserved.

Ultrastructural study of ectomycorrhizas on Pinus caribaea Morelet. var. hondurensis Barr. & Golf. seedlings

A ultraestrutura das ectomicorrizas formadas por Pinus caribaea var. hondurensis inoculado com Pisolithus tinctorius (Pers.) Coker & Couch e Telephora terrestris (Ehrenb.) Fr. foi analisada antes do transplantio dessas mudas para o campo, com o intuito de verificar se o fungo estava estabelecido nas raízes. Os fungos ectomicorrízicos inoculados formaram um manto compacto e bem desenvolvido nas raízes laterais. Nas hifas desse manto foram observados vacúolos, núcleos e septos dolipóricos, enquanto que no citoplasma das hifas da rede de Hartig, que ficam adjacentes às células corticais, foram freqüentemente observados vários núcleos, retículo endoplasmático e mitocôndrias polimórficas. Células corticais altamente vacuolizadas, contendo gotículas de material elétron-denso, apresentaram núcleo e algumas organelas na sua estreita região citoplasmática periférica. As ectomicorrizas de P. caribaea var. hondurensis apresentaram características ultraestruturais de uma associação compatível e fisiologicamente ativa.

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.

Central nervous system of Rhipicephalus sanguineus ticks (Acari: Ixodidae): an ultrastructural study

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

Ultrastructural changes in the ovary cells of engorged Rhipicephalus sanguineus female ticks treated with esters of ricinoleic acid from castor oil (Ricinus communis)

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

Action of the chemical agent fipronil (active ingredient of acaricide Frontline (R)) on the liver of mice: An ultrastructural analysis

Fipronil, active ingredient of the acaricide Frontiline (R), is a phenyl-pyrazolic derivative, and its efficacy in the elimination of several plagues, even in low concentrations, has already been demonstrated; however, its effect on nontarget organisms has not been thoroughly explained. In this sense, the objective of this study was to evaluate the effects of different dosages of fipronil on the liver of mice in artificial conditions. Results showed that the animals exposed to fipronil present significant ultrastrucutural changes in hepatic cells with evident cellular and cytoplasm disorganization in hepatocytes characterized by an increase in the number of organelles, mainly mitochondria and rough endoplasmic reticulum, organelles that, in the case of the exposed animals, were probably responsible for the enzymes' synthesis that have the function of inactivating the toxic metabolites. A fat accumulation in the hepatocytes' cytoplasm (steatosis) was observed, in addition to extended vacuolated areas, mainly in regions next to the cell nucleus. Alterations observed in the nuclei of the hepatocytes pointed out cell death processes. Moreover, Kupffer cells increased in number (hyperplasia) suggesting an increase in the phagocytic activity of the liver in the exposed animals. Microsc. Res. Tech., 2011. (c) 2011 Wiley Periodicals, Inc.

Salivary glands of Amblyomma cajennense (Acari: Ixodidae): a histological and an ultrastructural overview

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

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

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

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 Oocytes of Female Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) Ticks Subjected to the Action of Azadirachta indica A. Juss (Neem)

The present study provides ultrastructural information about the acaricidal effects of neem (Azadirachta indica A. Juss) on the ovaries of R. sanguineus engorged females. In general, the main damage caused in the oocytes was alteration in the shape of the cell and of the germinal vesicle, ring-shaped nucleolus, cytoplasmic vacuolation, and disorganization of the organelles and of the cell membranes (including the chorion), all of which indicate that these cells could be in the process of death. The results showed that azadirachtin would be an efficient acaricide agent for inhibiting and/or neutralizing the reproduction process of R. sanguineus females, impairing the reproductive ability of this species.

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)