Search results for "Microscopy"
showing 10 items of 3390 documents
The test skeletal matrix of the black sea urchin Arbacia lixula
2015
11 pages; International audience; In the field of biomineralization, the past decade has been marked by the increasing use of high throughput techniques, i.e. proteomics, for identifying in one shot the protein content of complex macromolecular mixtures extracted from mineralized tissues. Although crowned with success, this approach has been restricted so far to a limited set of key-organisms, such as the purple sea urchin Strongylocentrotus purpuratus, the pearl oyster or the abalone, leaving in the shadow non-model organisms. As a consequence, it is still unknown to what extent the calcifying repertoire varies, from group to group, at high (phylum, class), median (order, family) or low (g…
Proteomic analysis of exosome-like vesicles derived from breast cancer cells.
2012
Background/Aim: The phenomenon of membrane vesicle-release by neoplastic cells is a growing field of interest in cancer research, due to their potential role in carrying a large array of tumor antigens when secreted into the extracellular medium. In particular, experimental evidence show that at least some of the tumor markers detected in the blood circulation of mammary carcinoma patients are carried by membrane-bound vesicles. Thus, biomarker research in breast cancer can gain great benefits from vesicle characterization. Materials and Methods: Conditioned medium was collected from serum starved MDA-MB-231 sub-confluent cell cultures and exosome-like vesicles (ELVs) were isolated by ultra…
Nacre calcification in the freshwater mussel Unio pictorum: carbonic anhydrase activity and purification of a 95 kDa calcium-binding glycoprotein.
2008
9 pages; International audience; The formation of the molluscan shell is finely tuned by macromolecules of the shell organic matrix. Previous results have shown that the acid-soluble fraction of the nacre matrix of the freshwater paleoheterodont bivalve Unio pictorum shell displays a number of remarkable properties, such as calcium-binding activity, the presence of extensive glycosylations and the capacity to interfere at low concentration with in vitro calcium carbonate precipitation. Here we have found that the nacre-soluble matrix exhibits a carbonic anhydrase activity, an important function in calcification processes. This matrix is composed of three main proteinaceous discrete fraction…
Mass Spectrometry and Imaging Analysis of Nanoparticle-Containing Vesicles Provide a Mechanistic Insight into Cellular Trafficking
2014
Rational design of nanocarriers for drug delivery approaches requires an unbiased knowledge of uptake mechanisms and intracellular trafficking pathways. Here we dissected these processes using a quantitative proteomics approach. We isolated intracellular vesicles containing superparamagnetic iron oxide polystyrene nanoparticles and analyzed their protein composition by label-free quantitative mass spectrometry. The proteomic snapshot of organelle marker proteins revealed that an atypical macropinocytic-like mechanism mediated the entry of nanoparticles. We show that the entry mechanism is controlled by actin reorganization, atypical macropinocytic signaling, and ADP-ribosylation factor 1. A…
Recent Advances in Affinity MOF-Based Sorbents with Sample Preparation Purposes
2020
This review summarizes the recent advances concerning metal–organic frameworks (MOFs) modified with several biomolecules (e.g., amino acids, nucleobases, proteins, antibodies, aptamers, etc.) as ligands to prepare affinity-based sorbents for application in the sample preparation field. The preparation and incorporation strategies of these MOF-based affinity materials were described. Additionally, the different types of ligands that can be employed for the synthesis of these biocomposites and their application as sorbents for the selective extraction of molecules and clean-up of complex real samples is reported. The most important features of the developed biocomposites will be discussed thr…
Mineralogical and Chemical Records of Icelandic Dust Sources Upon Ny-Ålesund (Svalbard Islands)
2018
This work aims to identify the geochemical and mineralogical markers of Icelandic dust and to differentiate it from the dust of local origin deposited at the Ny-Ålesund station. We characterized representative sediment samples from Iceland and Svalbard and compared them to a set of aerosol samples collected in Ny-Ålesund to check the existence and type of the mineralogical markers. The sediment samples were analyzed by X-ray diffraction (XRD) to detect the mineralogical constrain of the geochemical markers. Both aerosol and sediment samples were examined by scanning electron microscopy coupled with EDS microanalysis (SEM-EDS) and image analysis to detect and to provide a morpho-chemical cha…
Compact and Field Portable Biophotonic Sensors for Automated Cell Identification (Plenary Address)
2021
In this Plenary address paper, we overview recently published work for automated cell identification using 3D optical imaging in compact and field portable biophotonic sensors. Digital holographic microscopy systems and lensless pseudorandom phase encoding systems capture 3D information of biological cells and make highly accurate automated cell identification possible. Overviewed systems include sickle cell disease diagnosis based on spatio-temporal cell dynamics in a field-portable 3D-printed shearing digital holography as well as lensless cell identification of both single and multicell samples using pseudorandom phase encoding.
Pterostilbene-induced tumor cytotoxicity: a lysosomal membrane permeabilization-dependent mechanism.
2012
The phenolic phytoalexin resveratrol is well known for its health-promoting and anticancer properties. Its potential benefits are, however, limited due to its low bioavailability. Pterostilbene, a natural dimethoxylated analog of resveratrol, presents higher anticancer activity than resveratrol. The mechanisms by which this polyphenol acts against cancer cells are, however, unclear. Here, we show that pterostilbene effectively inhibits cancer cell growth and stimulates apoptosis and autophagosome accumulation in cancer cells of various origins. However, these mechanisms are not determinant in cell demise. Pterostilbene promotes cancer cell death via a mechanism involving lysosomal membrane …
Pulmonary microvascular architecture in hereditary haemorrhagic telangiectasia
2017
A 24-year-old Caucasian man was admitted with a known hereditary haemorrhagic telangiectasia (HHT) and heterozygous mutation of factor V Leiden following episodes of cerebral infarctions in occipital lobes, cerebellum and brainstem. In his case history, the patient underwent several interventional embolisation of arteriovenous (AV) malformations in the middle and lower lobes (figure 1). However, those were not completely successful as the malformations were diffuse. We performed video-assisted thoracoscopic surgery with a resection of the middle lobe and a wedge resection of segment 10. Figure 1 CT scans depict the pulmonary arteriovenous malformations after re-embolisation in the middle lo…
The murine bronchopulmonary microcirculation in hapten-induced inflammation
2006
ObjectiveThe clinical observation of central bronchial artery hypertrophy in chronic lung inflammation suggests the possibility that the bronchial circulation may also participate in adaptive responses in peripheral lung inflammation.MethodsTo investigate the potential role of the bronchial microcirculation in peripheral lung inflammation, we developed a murine model of lung inflammation using the intratracheal instillation of the peptide-hapten trinitrophenol in presensitized mice.ResultsClinical parameters indicated a peak inflammatory response at 96 hours. Similarly, gross and microscopic evidence of inflammation was observed 96 hours after antigen instillation. Using a forced oscillatio…