Publications by authors named "Jehan Waeytens"

L. is cultivated nowadays for agricultural, industrial, and medicinal applications and also for recreational use. The latter is due to the presence of delta-9-tetrahydrocannabinol, a psychoactive substance.

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Under specific conditions, some proteins can self-assemble into fibrillar structures called amyloids. Initially, these proteins were associated with neurodegenerative diseases in eucaryotes. Nevertheless, they have now been identified in the three domains of life.

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Hfq is a pleitropic actor that serves as stress response and virulence factor in the bacterial cell. To execute its multiple functions, Hfq assembles into symmetric torus-shaped hexamers. Extending outward from the hexameric core, Hfq presents a C-terminal region, described as intrinsically disordered in solution.

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The possible carrier role of Outer Membrane Vesicles (OMVs) for small regulatory noncoding RNAs (sRNAs) has recently been demonstrated. Nevertheless, to perform their function, these sRNAs usually need a protein cofactor called Hfq. In this work we show, by using a combination of infrared and circular dichroism spectroscopies, that Hfq, after interacting with the inner membrane, can be translocated into the periplasm, and then be exported in OMVs, with the possibility to be bound to sRNAs.

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Poldip2 was shown to be involved in oxidative signaling to ensure certain biological functions. It was proposed that, in VSMC, by interaction with the Nox4-associated membrane protein p22, Poldip2 stimulates the level of reactive oxygen species (ROS) production. In vitro, with fractionated membranes from HEK393 cells over-expressing Nox4, we confirmed the up-regulation of NADPH oxidase 4 activity by the recombinant and purified Poldip2.

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Nanoscale infrared spectroscopy (AFMIR) is becoming an important tool for the analysis of biological sample, in particular protein assemblies, at the nanoscale level. While the amide I band is usually used to determine the secondary structure of proteins in Fourier transform infrared spectroscopy, no tool has been developed so far for AFMIR. The paper introduces a method for the study of secondary structure of protein based on a protein library of 38 well-characterized proteins.

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Fossil sourced chemicals such as aromatics, are widely employed in the chemical industry for the production of commodity items. Recognizing the un-sustainability of existing approaches in the production of these chemicals, the current study investigated the valorization of apple pomace (AP) for their production. The present study assessed AP valorization by imposing variations in processing conditions of temperature (100-260 °C), time (0.

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Hfq is a pleiotropic regulator that mediates several aspects of bacterial RNA metabolism. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, usually via its interaction with small regulatory RNAs. Previously, we showed that the Hfq C-terminal region forms an amyloid-like structure and that these fibrils interact with membranes.

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Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and orientated circular dichroism (OCD) are complementary spectroscopies widely used for the analysis of protein samples such as the amyloids commonly renowned as neurodegenerative agents. Determining the secondary structure content of proteins, such as aggregated β-sheets inside the amyloids and in various environments, including membranes and lipids, has made these techniques very valuable and complemental to high-resolution techniques such as nuclear magnetic resonance (NMR), X-ray crystallography, and cryo-electron microscopy. FTIR and CD are extremely sensitive to structural changes of proteins due to environmental changes.

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Amyloid inhibitors, such as the green tea compound epigallocatechin gallate EGCG, apomorphine or curlicide, have antibacterial properties. Conversely, antibiotics such as tetracycline derivatives or rifampicin also affect eukaryotic amyloids formation and may be used to treat neurodegenerative diseases. This opens the possibility for existing drugs to be repurposed in view of new therapy, targeting amyloid-like proteins from eukaryotes to prokaryotes and conversely.

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Atomic force microscopy has been used for decades to study the topography of proteins during aggregation but with a lack of information on the secondary structure. On the contrary, infrared spectroscopy was able to study structural changes during the aggregation, but this analysis is complicated due to the presence of different species in mixtures and the poor spatial (~μm) resolution of the FTIR microscopy. Recently, Professor Alexandre Dazzi combined those techniques in the so-called AFM-IR.

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Environmental pollution by the nearly nonbiodegradable polyethylene (PE) plastics is of major concern; thus, organisms capable of biodegrading PE are required. The larvae of the Greater Wax Moth, (Gm), were identified as a potential candidate to digest PE. In this study, we tested whether PE was metabolized by Gm larvae and could be found in their tissues.

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Due to massive production, inefficient waste collection, and long lives, plastics have become a source of persistent pollution. Biodegradation is explored as an environmentally friendly remediation method for removing plastics from the environment. Microbial and animal biodegradation methods have been reported in the literature for various plastics.

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Amyloid fibrils are composed of aggregated peptides or proteins in a fibrillary structure with a higher β-sheet content than their native structure. Attenuated total reflection Fourier transform infrared spectroscopy only provides bulk analysis of a sample therefore it is impossible to discriminate between different aggregated structures. To overcome this limitation, near-field techniques like AFM-IR have emerged in the last twenty years to allow infrared nanospectroscopy.

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Amyloid fibrils are composed of aggregated peptides or proteins in a fibrillar structure with a higher β-sheet content than in their native structure. To characterize them, we used an innovative tool that coupled infrared spectroscopy with atomic force microscopy (AFM-IR). With this method, we show that we can detect different individual aggregated species from oligomers to fibrils and study their morphologies by AFM and their secondary structures based on their IR spectra.

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Infrared (IR) spectromicroscopy allows chemical mapping of a kidney biopsy. It is particularly interesting for chemical speciation of abnormal tubular deposits and calcification. In 2017, using IR spectromicroscopy, we described a new entity called vancomycin cast nephropathy.

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The abnormal repetition of the hexanucleotide GGGGCC within the C9orf72 gene is the most common genetic cause of both Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). Different hypothesis have been proposed to explain the pathogenicity of this mutation. Among them, the production of aberrant proteins called Dipeptide Repeat Proteins (DPR) from the repeated sequence.

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The Hfq protein is reported to be involved in environmental adaptation and virulence of several bacteria. In Gram-negative bacteria, Hfq mediates the interaction between regulatory noncoding RNAs and their target mRNAs. Besides these RNA-related functions, Hfq is also associated with DNA and is a part of the bacterial chromatin.

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