Search results for "PROTEINS"

Polysarcosine-Based Lipids: From Lipopolypeptoid Micelles to Stealth-Like Lipids in Langmuir Blodgett Monolayers.

2016

Amphiphiles and, in particular, PEGylated lipids or alkyl ethers represent an important class of non-ionic surfactants and have become key ingredients for long-circulating (“stealth”) liposomes. While poly-(ethylene glycol) (PEG) can be considered the gold standard for stealth-like materials, it is known to be neither a bio-based nor biodegradable material. In contrast to PEG, polysarcosine (PSar) is based on the endogenous amino acid sarcosine (N-methylated glycine), but has also demonstrated stealth-like properties in vitro, as well as in vivo. In this respect, we report on the synthesis and characterization of polysarcosine based lipids with C14 and C18 hydrocarbon chains and their end g…

Sponge‐Like Behaviour in Isoreticular Cu(Gly‐His‐X) Peptide‐Based Porous Materials

2015

We report two isoreticular 3D peptide-based porous frameworks formed by coordination of the tripeptides Gly-L-His-Gly and Gly-L-His-L-Lys to Cu(II) which display sponge-like behaviour. These porous materials undergo structural collapse upon evacuation that can be reversed by exposure to water vapour, which permits recovery of the original open channel structure. This is further confirmed by sorption studies that reveal that both solids exhibit selective sorption of H2 O while CO2 adsorption does not result in recovery of the original structures. We also show how the pendant aliphatic amine chains, present in the framework from the introduction of the lysine amino acid in the peptidic backbo…

Physico-chemical characterisation of a non-conventional food protein source from earthworms and sensory impact in arepas

2009

International audience; This study aimed to characterise a non-conventional protein source: a powder made from earthworms, and to evaluate its potential use as human food. The way it was prepared led to low solubility and wide particle size distribution. Sensory analysis was used to assess the acceptability and the organoleptic properties of maize-based pan-cakes fortified with this novel protein powder. Satisfying products were obtained with a substitution level of 5.5% (w/w) earthworm powder in pan-cakes. GC-MS allowed the identification of more than seventy volatile compounds that may be responsible for the off-odour of the powder. The most abundant chemical groups found in the volatile …

Prostaglandin E2 and prostaglandin F2 alpha as endometrial receptivity biomarkers in successful embryo implantation

2014

Failure in the adhesion of the human blastocyst to the endometrium has been described as an important cause of infertility. Establishing the period of the so-called window of implantation and understanding the molecular mechanisms associated with embryo implantation has clinical and scientific implications. While over the last decades histological evaluation has been used to determine the phase of the menstrual cycle of the endometrium, the poor information obtained has made the case of using new technologies to identify specific markers, understand and characterize the receptive stage. This doctoral thesis investigates the existence, function and clinical impact of two specific lipids, the…

Immobilization of proteins in silica gel: Biochemical and biophysical properties

2015

The development of silica-based sol-gel techniques compatible with the retention of protein structure and function started more than 20 years ago, mainly for the design of biotechnological devices or biomedical applications. Silica gels are optically transparent, exhibit good mechanical stability, are manufactured with different geometries, and are easily separated from the reaction media. Biomolecules encapsulated in silica gel normally retain their structural and functional properties, are stabilized with respect to chemical and physical insults, and can sometimes exhibit enhanced activity in comparison to the soluble form. This review briefly describes the chemistry of protein encapsulat…

Molecular mechanisms underlying proteins-membrane interaction

Proteomics in antitumor research

2006

Proteins are the molecular players of fine-tuned regulatory pathways that underlie the behavior of any cell type. Derangement of this wide protein circuitry has a profound effect on cell life and ultimately contributes to the development of diseases such as cancer. New proteomic technologies are rapidly evolving to define and characterize the nodes of this altered protein network, both inside and outside cancer cells. Hopefully, these technologies will become user-friendly laboratory tools to improve cancer management from early detection to the development of rational and patient-tailored therapeutic strategies.

Transport of Arabidopsis GPI-anchored proteins along the early secretory pathway: Role of GPI-anchor remodelling and p24 proteins

2019

Las proteínas con anclaje GPI son una familia de proteínas que están ancladas a la cara exterior de la membrana plasmática mediante un ancla GPI y se ha visto que juegan un papel clave en plantas. Sin embargo, la maquinaria molecular implicada en el transporte de estas proteínas a la membrana plasmática en plantas es aún desconocida. Las proteínas p24 tienen un papel importante en el control de calidad de proteínas (posiblemente incluyendo las proteínas con anclaje GPI) transportadas entre el Retículo Endoplasmático y el aparato de Golgi. Esta tesis doctoral tiene como objetivo el estudio de la posible implicación de las proteínas p24 en la salida del Retículo Endoplasmático y en la localiz…

Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes

2019

Proton diffusion (PD) across biological membranes is a fundamental process in many biological systems, and much experimental and theoretical effort has been employed for deciphering it. Here, we report on a spectroscopic probe, which can be tightly tethered to the membrane, for following fast (nanosecond) proton transfer events on the surface of membranes. Our probe is composed of a photoacid that serves as our light-induced proton source for the initiation of the PD process. We use our probe to follow PD, and its pH dependence, on the surface of lipid vesicles composed of a zwitterionic headgroup, a negative headgroup, a headgroup that is composed only from the negative phosphate group, or…

Contribution des interactions tanins - protéines salivaires dans la sensation d'astringence

2015

National audience