The nuclear DNA of eukaryotic organisms is associated with several proteins. These proteins together with the DNA form chromatin. In all eukaryotes, DNA is folded around a core of histones to form nucleosomes. Chromatin was previously believed to serve mainly to organize and compact the genetic material. However, in recent years, chromatin has been regarded has a highly dynamic structure responsible for controlling gene expression. Therefore, chromatin is highly flexible, to make genetic information accessible when needed, and the degree of compaction has to be tightly regulated. DNA staining, using 4',6-diamidino-2-phenylindole (DAPI), provided the basis for a cytological distinction between weakly stained euchromatin, now known to be gene rich, and brightly stained heterochromatin, which usually contains various repetitive sequences. In many organisms, heterochromatic DNA is hypermethylated and this is used as an additional mechanism to regulate transcription. Histones can be modified by acetylation, phosphorylation, methylation or ubiquitination. These mechanisms provide signals to which other factors can bind and additionally alter the biochemical properties of chromatin (i.e., “histone code”). In general, acetylation of histones is correlated with active genes, whereas methylation of histones at different positions results in changes in gene expression. The methylation of lysine 9 in histone 3 (H3K9) is associated with heterochromatin formation while methylation of lysine 4 of histone 3 (H3K4) methylation is related to gene activation and positioned in euchromatin. DNA and histone modifications recruit various non-histone proteins to specific chromosomal regions and eventually create a defined nuclear structure that is able to affect gene expression.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Protein phosphatase 1 (PPP1) is the PPP most ubiquitous and each isoform interact with regulatory subunits that may be responsible for their subcellular localization. We identified PPP1R15B, C1ORF71 as novel regulators and the aim of this study was their further characterization in carcinoma cells. We analysed localization of each regulator in MDA-MB-468 cells and we transfected with constructs that we made with each as a GFP-fusion protein. For PPP1 cellular localization we used specific antibodies for each isoform. We observed the cells under a fluorescent microscope and LSM and we quantified co-localization. We found a high overlap coefficient of both the novel proteins with PPP1alpha and PPP1gamma1. We propose a model in which PPP1 regulator interacts with one or two regulatory subunits that may be used as target for therapeutic strategies.

Currently, only few antiviral drugs of proven effectiveness exist against virus of the Herpesviridae family and viral resistance to these drugs, especially in the immunocompromised hosts, has encouraged research for new drugs. Some porphyrin derivatives revealed a significant antiviral activity against HSV-1 virus. However the cellular target of the porphyrin derivatives in the virus-cell complex remains unknown.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Ranaviruses are known to produce iseases in fish, amphibians and reptiles, being involved in high mortality episodes in aquaculture farms and in the decline of amphibian populations worldwide. Mass mortality episodes were previously detected in Triturus marmoratus from two lagoons of the Peneda-Gerês National Park (PGNP) (NW Portugal). Ranavirus-like particles were identified in tissues of diseased newts T. marmoratus and T. boscai. Here we report on the molecular and ultrastructural characterization of these viruses.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

In testis we find mainly PPP1gamma2 isoform. We hypothesize that in different cell types we can find different regulatory subunits that may constitute targets for therapeutics of diseases such as male infertility, cancer and Alzheimer's disease. We identified a novel alternative splicing isoform of IIIG9 in testis, a known regulator of PPP1, IIIG9sT, and the aim of this study was its further characterization. We used a specific antibody for IIIG9sT in order to characterize its localization in bovine sperm cells. We also transfected IIIG9sT-GFP construct in mouse spermatogonia cells (GC-1 cells) and we used specific antibodies for each PPP1 isoform for the colocalization studies. We observed them under a fluorescent microscope and a LSM and quantified a high co-localization with PPP1gamma1 and 2 isoforms.

Pollutant particles of small size are produced and resuspended every day as a result of traffic. These particles, identified as particulate matter (PM10, PM2.5), can affect human health when inhaled, mostly the respiratory and cardiopulmonary systems. Some of these particles are ferromagnetic (s.l.) and their magnetic properties indicate their sources, composition and size. Coimbra is an inland city situated in the center of Portugal at a distance of 40 km from the coast. Coimbra has a total area of 320 km2 and a population of about 168.000. Motor vehicle traffic is the main source of air pollutant in the city. The main goal of this research is to assess pollution levels in the urban area of Coimbra using the magnetic properties of microscopic pollutant particles on Nerium oleander leaves.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Phytophthora cinnamomi has been reported to be regularly associated with cork and holm oak decline. This oomycete secretes elicitins, a group of unique highly conserved proteins that can enhance plant defence reactions.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

The selection of native Lavandula species and their economic exploitation have increased in the last few years. Micropropagation techniques have been used as an alternative for vegetative propagation allowing the multiplication of selected genotypes and chemotypes. Our previous studies showed that the essential oils of Lavandula pedunculata have an important antifungal activity against dermatophyte strains. Therefore, a new line of investigation concerning the in vitro culture of this species is justified. In the present study we compare the morphology of the leaf trichomes and the chemical composition of their essential oils in both field-growing and in vitro propagated plants.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Helicobacter pylori is a helical shaped Gram-negative bacterium that colonizes the human stomach. It is associated with several human pathologies, such as gastritis, peptic ulcer, and gastric cancer. The standard first-line treatment is a one week triple therapy: the association of two antibiotics, most frequently amoxicillin and clarithromycin, and a proton pump inhibior. Despite the evolution of the treatment strategy, quadruple therapy, there is an increasing percentage of failure of the antibiotic therapy, due to antibiotics resistance. Phage therapy is the therapeutic use of lytic bacteriophages to treat pathogenic bacterial infections and H. pylori is a good target. However there are no available phage collections, and H. pylori phages description is diminutive on literature.

Erectile Dysfunction (ED), the inability to achieve or maintain an erection of sufficient rigidity for completion of sexual act, is a common condition affecting more than 150 million of men worldwide. This disorder is highly associated with aging, however concomitant pathologies such as hyperlipidemia, hypertension, and diabetes also contribute to ED progression. In the Massachusetts Male Aging Study, age was considered an independent variable strongly associated with ED, showing that the prevalence of this disease increased with age from 38% in the youngest group of men (mean age 40 y.) to almost 70% in the oldest group of men examined (mean age 70 y.). It is well demonstrated that aging leads to changes in the cardiovascular system, which results in a decrease in elasticity due to fibrosis and an increase in stiffness of the arterial system, independently of the effects of concurrent pathologies. Vasculogenic ED is the most prevalent condition, affecting nearly 80% of patients with organic etiology. Small vessels of the penis are very sensitive to structural and functional changes, and small disturbances can conduce to ED. ED is now considered by some authors as synonymous to endothelial dysfunction and an early manifestation of atherosclerosis, being a precursor of systemic vascular disease. Human cavernous tissue is mainly constituted by smooth muscle fibers that surround sinusoid vessels. Corpus cavernosum structural elements act in concert, allowing increase of intra-cavernous arterial flow and smooth muscle relaxation processes which are fundamental to penile erection. The aim of this study was to compare the ultrastructural anatomy of the young and aged human corpus cavernosum, in the absence of additional risk factors.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008