Accueil >
Production scientifique
Physique de systèmes biologiques
(3) Production(s) de l'année 2024
|
|
Doping feruloylated arabinoxylan covalent hydrogels with cellulose nanocrystals 
Auteur(s): Antoine-Assor Carole, In M., Moreau Céline, Micard Valérie, Cassan Denis
(Affiches/Poster)
Journées scientifiques GDR SLAMM (Le Croisic (FR), FR), 2024-11-04
Ref HAL: hal-04791099_v1
Exporter : BibTex | endNote
Résumé: To enhance the viscoelastic properties of Feruloylated Water Extractable ArabinoXylan (F-WEAX) gels, F-WEAX were covalently linked by a laccase in the presence of cellulose nanocrystals (CNC). The CNC/ F-WEAX weight ratios varied from 0 to 1.5 at a constant F-WEAX concentration of 1 % (w/v). The resulting CNC/ F-WEAX gels became stiffer with increasing CNC content with the elastic modulus scaling as [CNC]3. CNC also altered the relaxation spectrum of the CNC/ F-WEAX gels: the loss factor increased at low frequencies while remaining constant at high frequencies. The strong affinity between F-WEAX and CNC was demonstrated by in situ QCM-D analysis which showed that F-WEAX adsorb spontaneously and irreversibly onto CNC. Following laccase oxidative gelation, the rate of recovered ferulic acid (FA) in di-and trimer forms was twice as high when oxidation occurred in the presence of CNC. Due their higher covalent cross-link density, the swelling capacity of F-WEAX-CNC gels slightly decreased. The increased elasticity of the F-WEAX-CNC gels can thus be attributed to 3 factors: a higher volume fraction of CNC leading to increased entanglement, a greater number of di- or tri-ferulic acid covalent cross-links between F-WEAX chains, and the formation of multiarm physical junctions between F-WEAX and CNC.
|
|
|
|
Suivi de bactéries en écoulement confiné par microscopie holographique numérique
Auteur(s): Becker Simon, Klopffer Lucie, Mathieu Laurence, Gross M., Louvet N.
Conference: Congrès Francophone de Techniques Laser (Lyon, FR, 2024-09-07)
Ref HAL: hal-04768058_v1
Exporter : BibTex | endNote
Résumé: Nous présentons dans cette étude une expérience de microscopie holographique numérique en ligne pour le suivi de bactéries en milieu confiné. Cette technique, simple de mise en œuvre, nous permet de caractériser la dynamique d'une suspension bactérienne dans un capillaire d'une centaine de micromètres. Nous présentons également le logiciel holotracker en libre accès qui permet de propager des hologrammes par la méthode du spectre angulaire et également d'utiliser différentes fonction de focus puis de tracking.
|
|
|
|
Phosphorylation of the F-BAR protein Hof1 drives septin ring splitting in budding yeast
Auteur(s): Varela Salgado Maritzaida, Adriaans Ingrid, Touati Sandra, Ibanes Sandy, Lai-Kee-Him Joséphine, Ancelin Aurélie, Cipelletti L., Picas Laura, Piatti Simonetta
(Article) Publié:
Nature Communications, vol. 15 p.3383 (2024)
Texte intégral en Openaccess : 
Ref HAL: hal-04732675_v1
PMID 38649354
DOI: 10.1038/s41467-024-47709-3
Exporter : BibTex | endNote
Résumé: A double septin ring accompanies cytokinesis in yeasts and mammalian cells. In budding yeast, reorganisation of the septin collar at the bud neck into a dynamic double ring is essential for actomyosin ring constriction and cytokinesis. Septin reorganisation requires the Mitotic Exit Network (MEN), a kinase cascade essential for cytokinesis. However, the effectors of MEN in this process are unknown. Here we identify the F-BAR protein Hof1 as a critical target of MEN in septin remodelling. Phospho-mimicking HOF1 mutant alleles overcome the inability of MEN mutants to undergo septin reorganisation by decreasing Hof1 binding to septins and facilitating its translocation to the actomyosin ring. Hof1-mediated septin rearrangement requires its F-BAR domain, suggesting that it may involve a local membrane remodelling that leads to septin reorganisation. In vitro Hof1 can induce the formation of intertwined septin bundles, while a phosphomimetic Hof1 protein has impaired septin-bundling activity. Altogether, our data indicate that Hof1 modulates septin architecture in distinct ways depending on its phosphorylation status.
|
