Laboratory of Electronic Microscopy

Rome, Italy

Laboratory of Electronic Microscopy

Rome, Italy
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Kreft M.E.,University of Ljubljana | Di Giandomenico D.,Laboratory of Electronic Microscopy | Beznoussenko G.V.,Laboratory of Electronic Microscopy | Resnik N.,University of Ljubljana | And 2 more authors.
Biology of the Cell | Year: 2010

Background information. The GA (Golgi apparatus) has an essential role in membrane trafficking, determining the assembly and delivery of UPs (uroplakins) to the APM (apical plasma membrane) of superficial UCs (uroepithelial cells) of urinary bladder. UPs are synchronously and uniformly delivered from the GA to the APM by DFVs (discoidalor fusiform-shaped vesicles); however, themechanism of UP delivery is not known.We have used the culture model of UCs with the capacity to undergo terminal differentiation to study the process of uniform delivery of DFVs to the APM and to elucidate the mechanisms involved. Results. By three-dimensional localization using confocal microscopy of immunofluorescence-labelled GA-related markers [GM130 (cis-Golgi matrix protein of 130 kDa), GS15 (Golgi Snare 15 kDa), GS28 and giantin], uroepithelial differentiation-related markers (UPs), MTs (microtubules; α-tubulin) and intermediate filaments [CK7 (cytokeratin 7) and CK20], we found that in non-differentiated, UP-negative UCs the GA is mostly organized as a single ribbonlike structure close to the nucleus, whereas in differentiated, UP-positive UCs the GA is fragmented and spread almost through the entire cell. The FRAP (fluorescence recovery after photobleaching) experiments on the UCs transfected with GalT (trans-Golgi/TGN enzyme β1,4-galactosyltransferase) fused to fluorescent protein showed that Golgi-resident enzyme cycles freely within ribbon-like GA but not within fragmented GA. By CLEM (correlative light-electron microscopy), we examined the GA fragments in cells expressing UPs. We found that GA fragments are fully functional and similar to the GA fragments that are formed after nocodazole treatment. Furthermore, we demonstrated that the reorganization of GA into a fragmented form is associated with the impairment of the MT organization in the basal, central and subapical cytoplasm and the accumulation of intermediate filaments in the apical cytoplasm that could affect the kinetics of MT star leading to the peripheral fragmentation of the GA in the differentiated UCs. Conclusions. The fragmentation of the GA and the subsequent spreading of GA to the cell periphery represent one of the key events that promote the uniform delivery of UPs over the entire APM of differentiating UCs and thus are of major importance in the final proper formation and maintenance of the blood-urine barrier. © The Authors.

da Rosa Zavareze E.,Grande Rio University | da Rosa Zavareze E.,Federal University of Pelotas | Telles A.C.,Grande Rio University | Mello El Halal S.L.,Grande Rio University | And 6 more authors.
LWT - Food Science and Technology | Year: 2014

The objective of this study was to produce encapsulated protein hydrolysates from Whitemouth croaker (Micropogonias furnieri) muscle and its industrialization byproduct. The protein hydrolysates were prepared from the muscle (MPH) and byproduct (BPH) from croaker by enzymatic hydrolysis using Flavourzyme®. The hydrolysates were encapsulated using phosphatidylcholine as the wall material of the capsules. The capsules were evaluated for particle size, polydispersity, encapsulation efficiency, zeta potential, morphology, thermal properties, Fourier transform infrared (FTIR) spectroscopy and antioxidant activity. The average size of the capsules for both MPH and BPH liposomes range between 266 and 263 nm with low polydispersity. The capsules showed high encapsulation efficiency of around 80%. The FTIR analysis allowed suggesting that there was an effective ionic complexation between phosphatidylcholine and hydrolysate peptides. The antioxidant activity of the hydrolysates and capsules containing MPH and BPH was similar to the activity of α-tocoferol, but lower than that of vitamin C. © 2014 Elsevier Ltd.

Munguia N.M.,National University of Costa Rica | Gonzalez J.M.M.,Institute Seguridad Social Del Estado Of Me Xico Y Municipios | Solis-Arrieta L.,Laboratory of Electronic Microscopy | Osorio L.S.Y.,National University of Costa Rica
Advances in Skin and Wound Care | Year: 2014

OBJECTIVE: This study aimed to evaluate the distribution and concentration of silver eluted from silver-coated polyurethane dressing (V.A.C. GranuFoam Silver Dressing; KCI, San Antonio, Texas) in vitro and in patients undergoing negative-pressure wound therapy (NPWT). DESIGN: This was a descriptive study of the effect of silver-coated polyurethane dressing in patients undergoing NPWT. PARTICIPANTS: Six patients with infected wounds undergoing NPWT using silver-coated polyurethane dressing. INTERVENTIONS: To evaluate silver release in vitro, the authors soaked dressing fragments in water and human serum for different lengths of time and performed atomic absorption spectroscopy. For patient evaluation, the authors obtained exudate, serum, and wound tissue at different time points from 6 patients undergoing NPWT and measured silver levels by atomic absorption and dispersed x-ray spectroscopy. MAIN RESULTS: Silver from the dressing was immediately released in vitro at a rate 3 times greater in serum than in water. In vivo, silver was delivered to wound exudate at rates 102 to 104 times greater than in corresponding serum. Few surface silver deposits were detected in treated tissue. CONCLUSION: The high concentration of silver found in wound exudate reflects not only the affinity for silver in serum components and wound fluids, but also that most silver ions are not distributed systemically in the patient; instead, they are transported by the vacuum created by therapy. Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Fasseas C.,Laboratory of Electronic Microscopy | Akoumianaki-Ioannidou A.,Agricultural University of Athens
Acta Horticulturae | Year: 2010

Laurus nobilis is an evergreen shrub or tree native to the Mediterranean region. Known since ancient times in Greece it has many medicinal and culinary uses, but is mainly used for ornamental purposes in parks and gardens as well as roadside trees. Its leaves are bifacial, hypostomatic and in the temperate zone they are initiated throughout the year whenever the conditions are favourable. During the early stages of development leaves are soft and bright green in colour becoming dark green, hard and leathery when mature. This hardening of the leaves, as is revealed with light and electron microscopy, is due to secondary development of the vascular tissues, thickening and lignification of the walls of the bundle sheath extension cells and the walls of the epidermal cells. In the latter, thickening is more prominent on the adaxial epidermis with all the walls becoming thick and lignified during maturation and to a lesser extent on the abaxial epidermis with the external periclinal walls becoming thicker than the internal. Radial (anticlinal) walls of epidermal cells have field pits apparently not traversed by plasmodesmata and together with the tubular marginal pits of the external (periclinal) wall seem to provide plasticity for water fluctuations. Stomata are sunken with the guard cells embedded in the midregion of the stomatal pore side cell wall of the subsidiary cells thus allowing the opening and closing of the stomata which otherwise would have been difficult due to the hardness of the lignified epidermal cells. These anatomical characteristics allow the plant to withstand long periods of drought and make it an ideal ornamental plant for urban and sub-urban areas in temperate climates.

Zhang Y.,Nanjing Medical University | Zhao W.,Laboratory of Electronic Microscopy | Jiang Y.,Maternal and Child Health Hospital | Zhang R.,Nanjing Medical University | And 9 more authors.
Biology of Reproduction | Year: 2011

This study compared the ultrastructural differences of term placentae from human pregnancies resulting from assisted reproductive technology (ART) with term placentae from spontaneous human pregnancies. Term placentae were taken from women who had undergone an ART procedure (n = 8) and matched with term placentae from women who had had a spontaneous pregnancy (controls, n = 15). Using light microscopy (LM) and transmission-electron microscopy (TEM), terminal villi were evaluated with respect to the placental blood barrier, fetal capillaries, villous stroma, as well as cytotrophoblasts and syncytiotrophoblasts (ST) along with their substructures. No obvious differences were found between the ARTderived and control placentae when LM was used. With TEM, however, differences in the ultrastructural features were seen in the ART-derived placentae, specifically degenerative alterations of the terminal villi, mainly in ST, including a thicker placental barrier, decreased apical microvilli, and increased multiple vacuoles. The results demonstrate that some ultrastructural differences exist between ART-derived and control placentae with respect to the placental blood barrier, which may suggest maternofetal traffic downregulation following ART treatment. Further studies are required to understand the ultrastructural changes and their potential functional aspects in ART pregnancies. © 2011 by the Society for the Study of Reproduction, Inc.

PubMed | University of Sao Paulo and Laboratory of Electronic Microscopy
Type: Journal Article | Journal: Poultry science | Year: 2015

Astroviruses have been associated with enteric disorders in many animal species, including chickens. Here, we describe the isolation, propagation, and pathological characteristics of chicken astrovirus (CAstV) in specific pathogen free (SPF) chicken embryonated eggs (CEE) from chickens with diarrhea and runting-stunting syndrome. The CEE were inoculated via the yolk sac route. Viral confirmation was carried out using PCR techniques and transmission electron microscopy negative staining with ammonium molybdate. The intestinal contents were screened for CAstV, and differential diagnostic testing was performed for avian nephritis virus, avian rotavirus, avian reovirus, chicken parvovirus, infectious bronchitis virus, and fowl adenovirus Group I to detect co-infection with other infectious agents. Seven- or 14-day-old CEEs presented with hemorrhages, edema, a gelatinous aspect, deformities, and dwarfism. The supporting membranes did not show any alterations. Here, we have described the isolation of CAstV and its pathological characteristics in SPF CEE.

Dias A.R.G.,Federal University of Pelotas | da Rosa Zavareze E.,Federal University of Pelotas | Spier F.,Federal University of Pelotas | de Castro L.A.S.,Laboratory of Electronic Microscopy | Gutkoski L.C.,University Of Passo Fundo
Food Chemistry | Year: 2010

This study investigated the effects of annealing (ANN) on the properties of rice starches with high, medium and low-amylose contents. The starches were heated with excess water at 45°C, 50°C and 55°C for 16. h. The swelling power, solubility, pasting properties, enzymatic susceptibility, morphology and X-ray crystallinity of the starches were evaluated. Annealing reduced the swelling power and solubility of the starches. ANN at 55°C increased the pasting temperature and decreased the peak viscosity of the high-amylose rice starch. However, annealing decreased the peak viscosity of the low-amylose starch. The annealed rice starches presented a lower final viscosity and setback than did the native starches, with the exception of the low-amylose starch, which showed an increase in setback. Annealing increased the starches' susceptibilities to α-amylase and promoted a reduction in their relative crystallinity. © 2010 Elsevier Ltd.

Zavareze E.d.R.,Federal University of Pelotas | Storck C.R.,Federal University of Pelotas | de Castro L.A.S.,Laboratory of Electronic Microscopy | Schirmer M.A.,Federal University of Pelotas | Dias A.R.G.,Federal University of Pelotas
Food Chemistry | Year: 2010

The effect of heat-moisture treatment (HMT) on the properties of rice starches with high-, medium- and low-amylose content was investigated. The starches were adjusted to 15%, 20% and 25% moisture levels, and heated at 110 °C for 1 h. The swelling power, solubility, pasting properties, morphology, enzymatic susceptibility and X-ray crystallinity of the starches were evaluated. HMT reduced the swelling power and solubility of the starches. The strongest effect of HMT occurred on the high-amylose starch; the pasting temperature was increased and the peak viscosity, breakdown, final viscosity and the setback were reduced. HMT increased the starch's susceptibility to α-amylase and promoted a reduction in the starch relative crystallinity. © 2009 Elsevier Ltd. All rights reserved.

Mironov A.A.,Laboratory of Electronic Microscopy | Beznoussenko G.V.,Laboratory of Electronic Microscopy
Histology and Histopathology | Year: 2011

The formation of the Golgi ribbon takes place in protists and metazoans. It is especially prominent in mammalian cells during interphase. Golgi ribbon formation represents an orchestrated sequence of events based not only on different molecular mechanisms but also on discrete cellular functions. Mechanisms responsible for the generation of the Golgi ribbon include Golgi centralization, cis-and trans-Golgins, molecular machines responsible for the fusion of cargo domains with cisternal rims, and several other less studied factors. Here, we substantiate the hypothesis that cis-Golgins function mostly not as tethering factors, but are responsible for the attachment of the cis-most cisternae to the medial Golgi stacks, whereas trans-Golgins are responsible for the attachment of the transmost cisterna to the medial Golgi stacks. This hypothesis is tested analyzing predictions derived from it and related to molecular mechanisms responsible for mitotic fragmentation of Golgi stacks.

Falasca L.,Laboratory of Electronic Microscopy
International journal of STD & AIDS | Year: 2012

Giant cell hepatitis (GCH) has been rarely described in adult HIV patients, and its outcome remain unknown. We report two cases of GCH among 81 HIV patients co-infected with the hepatitis C virus (HCV). Both patients had a sustained virological response, suppression of HCV viral load and HIV viral suppression after highly active antiretroviral therapy. Our findings would suggest that the presence of giant cells does not influence the clinical course of hepatitis.

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