École de Biologie Industrielle

In this study, we evaluated the ability of three clay minerals and clay-like adsorbents, namely lipophilic organosilicates (OSL), LAPONITE® and montmorillonite (MMT), to extend the duration and released amount of UV filter. With only 4 % of benzophenone-3 (BZ-3), it was possible to obtain new sunscreen formulations stabilized by intercalating BZ-3 within the lamellar structures of the three adsorbents. The kinetics of BZ-3 release was studied through a membrane-free method in sink conditions using four mathematical kinetic models. The kinetics demonstrated that BZ-3 was released from the three adsorbents in a continuous and homogeneous way when powders of BZ-3 and OSL, LAPONITE® or MMT were combined at a similar dosage. We then focused on the effects of adsorbed BZ-3 on OSL particles. The sun protection evaluation tests suggested that the formulation using BZ-3 and OSL was executed accurately and efficiently. The F2 (OSL-BZ-3) showed the most effective broad-spectrum formulation with a higher λc (371) and UVA/UVB ratio (0.57) comparatively to F1 (with only 4% BZ3). Rheological analysis of F2 (OSL-BZ3) showed controlled viscosity, efficient spreadability, and enhanced structural integrity, which are key for uniform UV protection, stability, and consumer acceptability. The OSL-BZ-3 formulation provided an increased protection range and improved sunscreen photostability with respect to current regulations.

Developing olfactory expertise is essential in professions like perfumery, where the ability to describe, categorize, and conceptualize odors is critical. This study investigates how academic training during a 1.5-year program at a perfumery school (ISIPCA) shapes olfactory expertise of perfumery students. Forty students were assessed at three time points, focusing on odor description, evocation, recognition, discrimination, and categorization tasks. Results show that training significantly enhanced language abilities related to odor description and categorization. Students developed a richer and more precise vocabulary to characterize odors, aligning more closely with expert’s terminology and contributing to the formation of a shared olfactory lexicon. Semantic similarity within and between students, as well as with expert references, increased, emphasizing the importance of consistent language use in expertise development. Advanced natural language processing and machine learning tools revealed that the richness of verbal descriptions and semantic similarity were strong predictors of expertise acquisition. In contrast, improvements in non-verbal tasks, such as odor discrimination and recognition, were more limited, suggesting that perceptual abilities may require more extensive training or specialized methods. Building on these results, we propose potential enhancements to olfactory training including reinforced language practice, mental imagery exercises, and sensory discrimination tasks, along with personalized training strategies. These findings highlight the central role of language in the emergence of olfactory expertise and the importance of computational methods for optimizing training programs and advancing educational practices in olfactory science

Abstract Introduction Collagen plays a significant role in the development of pancreatic ductal adenocarcinoma (PDAC). Disease progression is mediated by a dense collagenous stroma, which acts as a barrier to drug delivery and immune cell access. Current in vitro models do not well represent the collagenous stroma seen in PDAC. The aim of this study is to develop a fibrillar collagen-based hydrogel system which mimics the tumour microenvironment seen in PDAC and assess cell-mediated collagen remodeling. Methods Metastatic SUIT2-007 pancreatic cancer cells, non-metastatic BxPC3 pancreatic cancer cells, and human pancreatic stellate cells (hPSCs) were encapsulated in bovine type I collagen gels of various concentrations. KPC mouse derived tumour organoids were also encapsulated in bovine type I collagen gels of 2 mg/ml and 6 mg/ml concentrations, basement membrane extract (BME), and a combination of BME and collagen gel. Cell viability and proliferation was assessed using Live/Dead imaging and CellTitre-Glo 3D respectively. Cell mediated collagen remodeling was assessed via monitoring of gel contraction on the mm scale, and confocal reflectance microscopy on the cellular scale. Collagen contraction around cells was assessed by measuring the pixel intensity of collagen fibrils within the vicinity of the cell. Cell phenotype was assessed via immunofluorescent staining and qPCR. Results Collagen concentration alters the hydrogel structure and stiffness, with 3 mg/ml collagen resulting in straighter, shorter and thicker fibrils. Metastatic SUIT-007 cells contracted collagen gels more rapidly than non-metastatic BxPC3 cells, with both achieving similar contraction by day 7. SUIT2-007 cells remodel and align soft 1 mg/ml gels while 3 mg/ml gels proved to be sufficiently stiff to resist remodeling. Cellular collagen association was increased in more elongated SUIT-007 cells than in BxPC3 cells. Organoid proliferation varies with hydrogel collagen concentration. Conclusion Metastatic SUIT2-007 cells were able to remodel collagen more rapidly and to a greater extent than non-metastatic BxPC3 cells. Collagen supports an invasive organoid phenotype. Collagen gels combined with confocal reflectance microscopy provide a platform for the quantitative assessment of cell-matrix interactions in PDAC. Acknowledgements This project was funded by a Medical Traineeship from UCD School of Medicine, and summer student scholarships from Irish Cancer Society and Breakthrough Cancer Research. We acknowledge the Conway Imaging Core Facility for assistance with microscopy. Citation Format: Ciara L Doyle, Shanu Xavier, Jarren Y.S Lu, Leah Fallon, Anwesha Sarkar, Jan J Baguyo, Maela Gars, Stephen D Thorpe. Collagen fiber architecture modulates PDAC cell and organoid phenotype [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A054.

International audience

While muscle and bone adaptations to deconditioning have been widely described, few studies have focused on the tendon enthesis. Our study examined the effects of mechanical loading on the structure and mechanical properties of the Achilles tendon enthesis. We assessed the fibrocartilage surface area, the organization of collagen, the expression of collagen II, the presence of osteoclasts, and the tensile properties of the mouse enthesis both after 14 days of hindlimb suspension (HU) and after a subsequent 6 days of reloading. Although soleus atrophy was severe after HU, calcified fibrocartilage (CFc) was a little affected. In contrast, we observed a decrease in non-calcified fibrocartilage (UFc) surface area, collagen fiber disorganization, modification of morphological characteristics of the fibrocartilage cells, and altered collagen II distribution. Compared to the control group, restoring normal loads increased both UFc surface area and expression of collagen II, and led to a crimp pattern in collagen. Reloading induced an increase in CFc surface area, probably due to the mineralization front advancing toward the tendon. Functionally, unloading resulted in decreased enthesis stiffness and a shift in site of failure from the osteochondral interface to the bone, whereas 6 days of reloading restored the original elastic properties and site of failure. In the context of spaceflight, our results suggest that care must be taken when performing countermeasure exercises both during missions and during the return to Earth.

Two vegetal oils have been selected for the formulation of pound cakes, rapeseed oil (RO) and palm oil (PO). The freshness of these products has been monitored during 58 days of storage. The RO pound cakes of 58 days as well as PO pound cakes presented higher values (p < .05) of hardness (N), Young's modulus (N.cm-2 ) and compressive stress (N.cm-2 ) than those aged of 5 days. For both vitamin A and tryptophan spectra, the maximum of fluorescence intensity varied according to the aging period. For both RO and PO recipes, lipid oxidation indicators (peroxide value, para-anisidine value, and total oxidation value [TOTOX]) were interestingly correlated to Young's modulus (R2 =0.99) as well as compressive stress (R2 =0.99), using polynomial model. The application of partial least squares regression to the vitamin A spectra provided excellent predictive results for both compressive stress (R2 = 0.99) and TOTOX (R2 =0.99). Good results were observed for tryptophan spectra for the prediction of TOTOX (R2 = 0.77). Thus, the use of front face fluorescence spectroscopy may provide rapid and accurate results for the monitoring of pound cakes freshness throughout storage.

Cyclodextrins (CDs) are conical molecules with a hydrophilic surface and a hydrophobic cavity. Thanks to the cavity, CDs are able to form inclusion complexes with a wide variety of guest molecules. A new oil-in-water (O/W) emulsifying system suitable for use in preparing Pickering emulsions with a large range of oils was developed. This system contains β-Cyclodextrin (β-CD) and a natural origin selected surfactant, Polyglyceryl-3 diisostearate (PG3D). The purpose of this work is to better understand the role of the PG3D in the realization and stabilization of these O/W emulsions. With this aim, O/W Pickering emulsions stabilized only by β-CD or β-CD/PG3D blends were prepared, and the effects of the presence of PG3D at different levels on the stability of emulsions were investigated. This original work was implemented using a wide range of complementary analytical methods, especially tensiometry, optical microscopy, laser granulometry, classical NMR and low field NMR measurements. The effectiveness of the β-CD/PG3D emulsifying system for preparing O/W Pickering emulsions appears due to synergistic effects between β-CD and PG3D. These molecules are both acting to stabilize the oil/water interface. The created particles have a high affinity for water with about the same contact angle as found for water. This may explain that only O/W emulsions are obtained using this system as in the case of using β-CD alone. PG3D by decreasing interfacial tension and due to its high wettability of the hydrophobic surfaces helps to get finer emulsions. An optimum β-CD/PG3D ratio must be used to obtain the most stable emulsions.

The emergence of MDR bacterial pathogens has directed antibiotic discovery research towards alternative therapies and traditional medicines. Boswellia sacra oleoresin (frankincense) was used to treat bacterial infections in traditional Arabian and Asian healing systems for at least 1000 years. Despite this, B. sacra extracts have not been rigorously tested for inhibitory activity against gastrointestinal pathogens or bacterial triggers of autoimmune diseases. Solvent extracts were prepared from Boswellia sacra oleoresins obtained from three regions near Salalah, Oman. MIC values were quantified against gastrointestinal pathogens and bacterial triggers of selected autoimmune diseases by disc diffusion and broth dilution methods. The antibacterial activity was also evaluated in combination with conventional antibiotics, and the class of interaction was determined by ΣFIC analysis. Isobolograms were used to determine the optimal ratios for synergistic combinations. Toxicity was evaluated by ALA and HDF cell viability bioassays. The phytochemical composition of the volatile components of all extracts was identified by nontargeted GC-MS headspace analysis. All methanolic extracts inhibited the growth of all of the bacteria tested, although the extracts prepared using Najdi oleoresin were generally more potent than the Sahli and Houjari extracts. Combinations of the methanolic B. sacra extracts and conventional antibiotics were significantly more effective in inhibiting the growth of several bacterial pathogens. In total, there were 38 synergistic and 166 additive combinations. Approximately half of the synergistic combinations contained tetracycline. All B. sacra extracts were nontoxic in the ALA and HDF cell viability assays. Nonbiased GC-MS headspace analysis of the methanolic extracts putatively identified a high diversity of monoterpenoids, with particularly high abundances of α-pinene. The antibacterial activity and lack of toxicity of the B. sacra extracts indicate their potential in the treatment and prevention of gastrointestinal and autoimmune diseases. Furthermore, the extracts potentiated the activity of several conventional antibiotics, indicating that they may contain resistance-modifying compounds.