Search results for "PROTEIN AGGREGATION"

Automatic Counting of Intra-Cellular Ribonucleo-Protein Aggregates in Saccharomyces cerevisiae Using a Textural Approach.

2019

AbstractIn the context of microbiology, recent studies show the importance of ribonucleo-protein aggregates (RNPs) for the understanding of mechanisms involved in cell responses to specific environmental conditions. The assembly and disassembly of aggregates is a dynamic process, the characterization of the stage of their evolution can be performed by the evaluation of their number. The aim of this study is to propose a method to automatically determine the count of RNPs. We show that the determination of a precise count is an issue by itself and hence, we propose three textural approaches: a classical point of view using Haralick features, a frequency point of view with generalized Fourier…

Quantification of HSP27 and HSP70 Molecular Chaperone Activities

2011

Stress-inducible heat-shock proteins (HSPs, like HSP70 and HSP27) are molecular chaperones that -protect cells from stress damage by keeping cellular proteins in a folding competent state and preventing them from irreversible aggregation. HSP27 and HSP70 chaperone activities are useful indicators to test chemical products and physical stress impact on protein denaturation, to select HSP inhibitors, or to -determine the implication of the chaperone function in other HSP activities, such as apoptosis. We have developed two simple and fast chaperone activity tests for HSP27 and HSP70 that we initially set up to test the effect of potential HSP inhibitors obtained after screening of chemical an…

Thermal aggregation of glycated bovine serum albumin

2010

International audience; Aggregation and glycation processes in proteins have a particular interest in medicine fields and in food technology. Serum albumins are model proteins which are able to self-assembly in aggregates and also sensitive to a non-enzymatic glycation in cases of diabetes. In this work, we firstly reported a study on the glycation and oxidation effects on the structure of bovine serum albumin (BSA). The experimental approach is based on the study of conformational changes of BSA at secondary and tertiary structures by FTIR absorption and fluorescence spectroscopy, respectively. Secondly, we analysed the thermal aggregation process on BSA glycated with different glucose con…

Blue autofluorescence in protein aggregates “lighted on” by UV induced oxidation

2019

Oxidation of amino acid side chains in protein structure can be induced by UV irradiation leading to critical changes in molecular structure possibly modifying protein stability and bioactivity. Here we show, by using a combination of multiple spectroscopic techniques and Fluorescence Lifetime Imaging, that UV-light exposure induces irreversible oxidation processes in Ubiquitin structure. In particular, the growth of a new autofluorescence peak in the blue region is detected, that we attribute to tyrosine oxidation products. Blue autofluorescence intensity is found to progressively increase also during aggregation processes leading to the formation of aggregates of non-amyloid nature. Signi…

Thermal aggregation of two “beta-protein” models at different pH values.

2005

Copper(II) and zinc(II) interaction with AB42: effects of metal binding on peptide’s aggregation rate and morphology of the aggregates.

2011

Congenital myopathies at their molecular dawning

2003

The introduction and application of molecular techniques have commenced to influence and alter the nosology of congenital myopathies. Long-known entities such as nemaline myopathies, core diseases, and desmin-related myopathies have now been found to be caused by unequivocal mutations. Several of these mutations and their genes have been identified by analyzing aggregates of proteins within muscle fibers as a morphological hallmark as in desminopathy and actinopathy, the latter a subtype among the nemaline myopathies. Immunohistochemistry has played a crucial role in recognizing this new group of protein aggregate myopathies within the spectrum of congenital myopathies. It is to be expected…

Proinflammatory and amyloidogenic S100A9 induced by traumatic brain injury in mouse model.

2019

Traumatic brain injury (TBI) represents a significant risk factor for development of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. The S100A9-driven amyloid-neuroinflammatory cascade occurring during primary and secondary TBI events can serve as a mechanistic link between TBI and Alzheimer’s as demonstrated recently in the human brain tissues. Here by using immunohistochemistry in the controlled cortical impact TBI mouse model we have found pro-inflammatory S100A9 in the brain tissues of all mice on the first and third post-TBI days, while 70% of mice did not show any S100A9 presence on seventh post-TBI day similar to controls. This indicates that defensive mechanisms effe…

Aggregation processes of intrinsically disordered proteins: influence of the environment

Valorization of apple peels through the study of the effects on the amyloid aggregation process of ?-casein

2021

Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of ?-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar "Fuji", cultivated in Sicily (Caltavuturo, Italy), inhibited ?-casein fib…