42 research outputs found
A highly sensitive atomic force microscope for linear measurements of molecular forces in liquids
We describe a highly improved atomic force microscope for quantitative nanomechanical measurements in liquids. The main feature of this microscope is a modified fiber interferometer mounted on a five axis inertial slider which provides a deflection sensitivity that is significantly better than conventional laser deflection based systems. The measured low noise floor of 572.0 fmHz provides excellent cantilever amplitude resolution. This allows us to operate the instrument far below resonance at extremely small cantilever amplitudes of less than 1 Å. Thus linear measurements of nanomechanical properties of liquid systems can be performed. In particular, we present measurements of solvation forces in confined octamethylcyclotetrasiloxane and water with amplitudes smaller than the size of the respective molecules. In general, the development of the instrument is important in the context of quantitative nanomechanical measurements in liquid environments. © 2005 American Institute of Physics
Urine E-cadherin: A Marker for early detection of kidney injury in diabetic patients.
Diabetic nephropathy (DN) is the main reason for end-stage renal disease. Microalbuminuria as the non-invasive available diagnosis marker lacks specificity and gives high false positive rates. To identify and validate biomarkers for DN, we used in the present study urine samples from four patient groups: diabetes without nephropathy, diabetes with microalbuminuria, diabetes with macroalbuminuria and proteinuria without diabetes. For the longitudinal validation, we recruited 563 diabetic patients and collected 1363 urine samples with the clinical data during a follow-up of 6 years. Comparative urinary proteomics identified four proteins Apolipoprotein A-I (APOA1), Beta-2-microglobulin (B2M), E-cadherin (CDH1) and Lithostathine-1-alpha (REG1A), which differentiated with high statistical strength (p < 0.05) between DN patients and the other groups. Label-free mass spectrometric quantification of the candidates confirmed the discriminatory value of E-cadherin and Lithostathine-1-alpha (p < 0.05). Immunological validation highlighted E-cadherin as the only marker able to differentiate significantly between the different DN stages with an area under the curve (AUC) of 0.85 (95%-CI: [0.72, 0.97]). The analysis of the samples from the longitudinal study confirmed the prognostic value of E-cadherin, the critical increase in urinary E-cadherin level was measured 20 ± 12.5 months before the onset of microalbuminuria and correlated significantly (p < 0.05) with the glomerular filtration rate measured by estimated glomerular filtration rate (eGFR)
Effect of in vitro gastrointestinal digestion on the total phenolic contents and antioxidant activity of wild Mediterranean edible plant extracts
The recent interest in wild edible plants is associated with their health benefits, which are mainly due to their richness in antioxidant compounds, particularly phenolics. Nevertheless, some of these compounds are metabolized after ingestion, being transformed into metabolites frequently with lower antioxidant activity. The aim of the present study was to evaluate the influence of the digestive process on the total phenolic contents and antioxidant activity of extracts from four wild edible plants used in the Mediterranean diet (Beta maritima L., Plantago major L., Oxalis pes-caprae L. and Scolymus hispanicus L.). HPLC-DAD analysis revealed that S. hispanicus is characterized by the presence of caffeoylquinic acids, dicaffeoylquinic acids and flavonol derivatives, P. major by high amounts of verbascoside, B. maritima possesses 2,4-dihydroxybenzoic acid, 5-O-caffeoylquinic acid, quercetin derivatives and kaempferol-3-O-rutinoside, and O. pes-caprae extract contains hydroxycinnamic acids and flavone derivatives. Total phenolic contents were determined by Folin-Ciocalteu assay, and antioxidant activity by the ABTS, DPPH, ORAC and FRAP assays. Phenolic contents of P. major and S. hispanicus extracts were not affected by digestion, but they significantly decreased in B. maritima after both phases of digestion process and in O. pes-caprae after the gastric phase. The antioxidant activity results varied with the extract and the method used to evaluate the activity. Results showed that P. major extract has the highest total phenolic contents and antioxidant activity, with considerable values even after digestion, reinforcing the health benefits of this species.European Union (FEDER funds through COMPETE)European Union (EU)European Union (FEDER)European Union (EU)Programa de Cooperacion Interreg V-A Espana - Portugal (POCTEP) 2014-2020 [0377_IBERPHENOL_6_E]project INTERREG - MD. Net: When Brand Meets PeopleFCT Portuguese Foundation for Science and Technolog
Definition of a consensus integrin adhesome and its dynamics during adhesion complex assembly and disassembly
Integrin receptor activation initiates the formation of integrin adhesion complexes (IACs) at the cell membrane that transduce adhesion-dependent signals to control a multitude of cellular functions. Proteomic analyses of isolated IACs have revealed an unanticipated molecular complexity; however, a global view of the consensus composition and dynamics of IACs is currently lacking. Here, we have integrated several IAC proteomes and generated a 2,412-protein integrin adhesome. Analysis of this dataset reveals the functional diversity of proteins in IACs and establishes a consensus adhesome of 60 proteins. The consensus adhesome likely represents a core cell adhesion machinery, centred around four axes comprising ILK-PINCH-kindlin, FAK-paxillin, talin-vinculin and α-actinin-zyxin-VASP, and includes underappreciated IAC components such as Rsu-1 and caldesmon. Proteomic quantification of IAC assembly and disassembly detailed the compositional dynamics of the core cell adhesion machinery. The definition of this consensus view of integrin adhesome components provides a resource for the research community
PRODUCTION OF MELT-SPUN Al-20Si-5Fe ALLOY AND BORON CARBIDE (B4C) COMPOSITE MATERIAL
In this study, metal matrix composite materials containing melt-spun Al-20Si-5Fe alloys and boron carbide was produced by high energy ball milling and then hot pressing at 200 MPa pressure and 450 degrees C. Mechanical and microstructural characterizations were performed by using an optical microscopy, X-Ray diffractometer, and dynamic microhardness tester. It was observed that boron carbide particles were homogenously distributed in the microstructure and values of microhardness and elastic modules were averagely 830 MPa and 42 GPa, respectively
PINCH-1 promotes Bcl-2-dependent survival signalling and inhibits JNK-mediated apoptosis in the primitive endoderm
The focal adhesion (FA) protein PINCH-1 is required for the survival of primitive endoderm (PrE) cells. How PINCH-1 regulates this fundamental process is not known. Here, we use embryoid bodies (EBs) and isolated EB-derived PrE cells to investigate the mechanisms by which PINCH-1 promotes PrE survival. We report that loss of PINCH-1 in PrE cells leads to a sustained activity of JNK and the proapoptotic factor Bax. Mechanistically, the sustained JNK activation was due to diminished levels of the JNK inhibitory factor Ras suppressor protein-1 (RSU-1), whose stability was severely reduced upon loss of PINCH-1. Chemical inhibition of JNK attenuated apoptosis of PrE cells but failed to reduce Bax activity. The increased Bax activity was associated with reduced integrin signalling and diminished Bcl-2 levels, which were shown to inhibit Bax. Altogether our findings show that PINCH-1 is a pro-survival factor that prevents apoptosis of PrE cells by modulating two independent signalling pathways; PINCH-1 inhibits JNK-mediated apoptosis by stabilising the PINCH-1 binding protein RSU-1 and promotes Bcl-2-dependent pro-survival signalling downstream of integrins
Crosslinking proteins modulate the self-organization of driven systems
The inherent activity of the cellular cytoskeleton is responsible for its unique properties - but at the same time impedes its thorough understanding. It is extremely challenging to predict to what extent the specific properties of its constituents affect the overall dynamic properties. By using high density motility assays, we show that the interplay of only three components - molecular motors, filamentous actin and crosslinking proteins - is sufficient for an extremely broad range of self-organization phenomena. They range from the assembly of large-scale polar structures to contracting networks and crucially depend on the specific properties of the crosslinking proteins
Erratum: Does urinary bladder shape affect urinary flow rate in men with lower urinary tract symptoms (The Scientific World Journal)
[No abstract available