Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Copper, an essential trace element, becomes toxic when its concentration exceeds certain natural levels. Recent in vitro studies demonstrated that copper overload of cells may induce apoptosis through caspase-3 activation. However, the precise mechanism of copper-induced apoptosis in fish is still unclear, even less in O. niloticus where no studies have been reported so far. Accordingly, the main aim of this study was to find if copper induces apoptosis in Oreochromis niloticus gill, through the caspase pathway. Additionally, we intended to evaluate the potential use of activated caspase-3 expression as a waterborne copper biomarker.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Studies demonstrated poor fertilization rates and compromised early embryo development in cases of oocytes with dark and granular ooplasm, or with central granular ooplasm and presence of a refractile body. Many other structural abnormalities of human mature oocytes do exist, but remain to be evaluated. In the present study we characterized granular vacuoles (GVa) of mature metaphase II human oocytes. Surplus abnormal MII oocytes (n=6) with GVa were used under informed consent, after controlled superovulation during IVF treatment cycles. In all cases, patients had normal karyotypes. For electron microscopy oocytes were fixed with karnovsky fixative for 2h at 4°C, post-fixed in 1-2% OsO4 in buffer containing 0,8% K3Fe3+(CN)6, dehydrated in ethanol series, equilibrated with propylene oxide and embedded in Epon. Semithin sections were stained with aqueous azur II and methylene blue (1:1). Ultrathin sections were stained with 3% aquous uranyl acetate (20 min) and Reynols lead citrate (10 min). Sections were observed with a transmission electron microscope JEOL 100CXII operated at 60kV.

Pulicaria is the third largest genus of the tribe Inuleae. It comprises ca. 80 species of shrubs, shrublets and herbs with a European, North African and Asian distribution. All of the 5 European species are represented in the Iberian Peninsula. The genus has taxonomic problems, as recent cladistic analysis showed that, like the other two great genera of Inuleae (Inula and Blumea), Pulicaria is a paraphyletic taxon. In fact, the species investigated so far were placed in two distinct clades. Moreover, the species status of Pulicaria microcephala, a Portuguese endemism of Berlengas Islands, is still controversial. As already demonstrated by several authors, the palynological data are of great importance to understand the evolution, taxonomy and ecology of the Asteraceae. However, in spite of a few relevant contributions, the palynology of Pulicaria is still insufficiently known. In the present work we investigated the palynology of the Iberian species of Pulicaria using light (LM) and scanning electron microscopy (SEM). The exine structure of Pulicaria paludosa was also investigated using transmission electron microscopy (TEM).

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Dendritic cells (DC) are major players in initiating immune responses by activating T-lymphocytes. They act as sentinels in peripheral tissues, continuously scavenging for antigens in their immediate surroundings. Their involvement in T-cell responses consists of a linear progression of events starting with capture of antigens in peripheral tissues, such as the skin, followed by migration to draining lymphoid organs and presentation of antigen-derived peptides to induce T-cell priming. In the last years, a number of DC lines have been generated and the electron microscopy has been used to define their characteristics, thus contributing to their formal validation. A cell line with features of early DC precursors was previously established from fetal mouse skin (FSDC), but its ultrastructural organization was not fully investigated. Here we report such investigation using light (LM), scanning electron (SEM) and transmission electron microscopy (TEM). The goal is to use FSDC as a model system to evaluate the safety and effectiveness of selected plant extracts, fractions and isolated polyphenols against inflammatory processes. Our preliminary results with these cells showed anti-inflammatory activity for some of the extracts we are currently investigating.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Lavandula species are aromatic plants that produce and accumulate essential oils in different types of glandular trichomes. The oils protect the aerial parts of the plant against herbivores and pathogens, and are of great economic value for fragrance, pharmaceutical, food and flavour industries. In Portugal there are five spontaneous species of Lavandula which are included in three different sections: Section Lavandula (L. latifolia), Section Pterostoechas (L. multifida) and Section Stoechas (L. luisieri, L. pedunculata, L. viridis). Our preliminary observations showed that these species have a high diversity of trichomes. This, associated with the fact that trichome morphology is often referred as an useful characteristic for systematic purposes, led us to investigate leaf trichome morphology in the five Portuguese species, using scanning electron microscopy (SEM).