No description available.

No description available.

No description available.

There is a wealth of scientific evidence associating the dietary intake of omega 3 long-chain polyunsaturated fatty acids with beneficial health properties. In this study, alternative natural sources of these polyunsaturated fatty acids are sought from novel low temperature isolated fungi. Over 100 low temperature isolated fungi were screened for very long chain polyunsaturated fatty acids (VLCPUF As), such as C20:5 n3 and C22:6 n3. Of those screened, only ten fungi were capable of VLCPUFA production, with Mortierella the predominant VLCPUF A producing species. Four Oomycete species were also capable of VLCPUF A production. It is thought that only basal fungal lineages, such as species from the Chytridiomycota and Zygomycota, are capable of VLCPUF A production. It was also found that VLCPUF As are not essential for growth at low temperatures, as Penicillium rugulosum, capable of producing 'fatty acids no longer or more unsaturated than C18:3 n3, demonstrated over 2 g of biomass per 100 ml of broth when grown at 5°C. This indicates that trienoic fatty acids are sufficient for maintaining membrane fluidity, although other factors may play a role in P. rugulosum's low temperature growth. Comparatively, VLCPUFA producing Mortierella species produced 200-250 mg of biomass, whereas the majority of non- VLCPUF A producing isolates produced 106-115 mg of biomass per 100 ml of broth. The total lipid unsaturation indices of nine isolates grown under three temperature regimes showed that the lowest growth temperature, 5°C, produced the highest un saturation index value III SIX of the organisms. 15°C produced the highest unsaturation index value in two of the isolates. This suggests that temperature has an effect on fungal lipid composition, and that lower temperatures may increase lipid unsaturation levels. It was also found that the ~6 elongase, initially identified from Mortierella alpina, is indicative for VLCPUF A producing fungi. The genomic conserved sequence found within ~6 elongases was used to develop primer sets that could be used with a PCR based methodology to screen fungal isolates for VLCPUF A production. The method successfully identified VLCPUF A producing Mortierella and Allomyces species, and was not found to amplify non-Ad elongases. Finally, recombinantPhaffia rhodozyma strains were developed using the ~5 desaturase and ~6 elongase from Mortierella alpina. The fatty acid profiles of the recombinant strains displayed novel fatty acids such as C20:2 n6 and C20:3 n3, and putatively, C18:2 ~5, 9 and C18:3 ~5, 9, 12 which correlated with the inserted genes.

Les bienfaits des acides gras oméga-3, essentiellement l’EPA (C20:5n-3) et le DHA (C22:6n-3) sont bien élucidés dans la littérature. Ils jouent en effet, un rôle essentiel dans la prévention de nombreuses maladies neurodégénératives et cardiovasculaires. Ces acides gras polyinsaturés à longue chaîne sont majoritairement retrouvés dans des sources d’origines marines. Dans ce contexte, nous nous sommes intéressés d’une part à l’effet du complexe phospholipopeptidique provenant de l’hydrolyse enzymatique des têtes de saumon, sur l’anxiété et le stress oxydant dans le cadre d’une étude comportementale effectuée sur un modèle murin. D’autre part, nous avons mis en place une approche de double vectorisation, sous formes de nanoémulsions, visant à augmenter la biodisponibilité de deux molécules hydrophobes et bioactives (coenzyme Q10 et curcumine) en utilisant les lipides totaux (phospholipides et triacylglycérols) du complexe phospholipopeptidique riche en EPA et en DHA. Les résultats de ce travail ont montré que le CPLP, sa fraction lipidique et peptidique ont un effet anxiolytique à une dose de 600 mg de CPLP/jour pendant 14 jours de traitement. Il a également été démontré dans cette étude que l’hydrolysat peptidique du CPLP diminue significativement, à double dose, le stress oxydant en baissant le niveau endogène des espèces réactives de l’oxygène (ROS) dans les neurones. D’autre part, pour une utilisation thérapeutique, la biodisponibilité du CoQ10 vectorisé à forte dose est améliorée jusqu’à 38 fois par la formulation huileuse composée de lipides polaires du CPLP. Concernant la supplémentation classique en CoQ10 en tant que complément alimentaire, la formulation émulsionnée présente une meilleure disponibilité à dose aigüe, avec une concentration plasmatique deux fois plus élevée que la formulation de référence. Malgré une activité anticancéreuse reconnue pour la curcumine, sa faible solubilité diminue sa biodisponibilité et limite de ce fait son utilisation. La formulation nanoémulsionnée de curcumine contribue à inhiber la prolifération de cellules cancéreuses (MCF7) / The benefits of omega 3 fatty acids, mainly EPA (C20:5n-3) and DHA (C22:6n-3) are well understood in the literature. They indeed play an essential role in the prevention of many neurodegenerative and cardiovascular diseases. These polyunsaturated fatty acids are mostly found in marine sources. In this context, we were interested on the effects of phospholipopeptidic complex from the enzymatic hydrolysis of salmon heads on anxiety and oxidative stress using a behavioural study (mouse model). On the other hand, we have developed a double vectorization operating nanoemulsions, to increase the bioavailability of two hydrophobic and bioactive molecules (conenzyme Q10 and curcumine) by total lipids (phospholipids and triacylglycerols) from the phospholipopeptidic complex rich in EPA and DHA. The results of this study showed that the CPLP, its lipid and peptide fractions have an anxiolytic effect at a dose of 600 mg of CPLP / day for 14 days of treatment. It was also demonstrated that the peptide’s hydrolyzate ingested at double dose decreases significantly the oxidative stress by lowering the endogenous level of reactive oxygen species (ROS) in neurons. For therapeutic uses, the bioavailability of CoQ10 increased up to 38 times compared to referential formulation when verctorized at high dose in the oily formulation composed of CPLP’s total lipids. Regarding conventional CoQ10 supplementation as a dietary supplement, the emulsified formulation has a better availability at single dose, with plasma concentrations two times higher than the reference formulation. Although the anti-cancer activity of curcumine is highlighted, its low solubility and hence its low bioavailability, are factors limiting its use. The formulation of nanoemulsified curcumine allows a significant reduction in the proliferation of cancer cells (MCF7)

Un des phénomènes sociétaux marquants de ces dernières années est le vieillissement de la population et en conséquence, une hausse considérable du nombre de personnes âgées. Dans ce contexte, la recrudescence des pathologies chroniques liées au vieillissement, dont la maladie d’Alzheimer, est devenue un enjeu majeur de santé publique. L’impact de nombreux facteurs environnementaux modulables, l’aspect chronique et évolutif des mécanismes pathogènes mis en jeu, doivent inciter à développer des interventions préventives permettant de minimiser les risques de développer ces maladies liées au vieillissement. Ce travail nous a permis de mettre en évidence l’importance d’utiliser des modèles d’étude et des modes d’expérimentation adaptés au vieillissement pour espérer en ralentir ou retarder les processus délétères. Nos résultats ont aussi permis d’identifier les membranes comme des éléments essentiels au bon fonctionnement cérébral. L’altération de la composition et de l’architecture des membranes neuronales chez la souris âgée perturbe leurs fonctionnalités et diminue les capacités de réponse neuroprotectrices recherchées notamment lors des thérapies anti-Alzheimer. Nous avons aussi observé des modifications membranaires comparables chez les souris rendues dyslipidémiques par un régime alimentaire excessif en lipides saturés auquel nous avons pu clairement attribuer un rôle pro-vieillissement. Nous avons finalement démontré le potentiel préventif d’une supplémentation alimentaire en acide docosahexaénoïque, l’acide gras polyinsaturé à longue chaîne majoritaire dans le cerveau, et pu conclure en sa capacité de restaurer une réponse neuroprotectrice altérée chez la souris âgée / One of the marked societal phenomena in recent decades is the aging of populations due to continually increasing lifespans and as a result, a considerable surge in the number and proportion of elderly, particularly in Western countries. In this demographic context, the rise of chronic diseases related to aging, including Alzheimer’s disease and other types of dementia, has become a major public health issue. The impact of modifiable environmental factors, evolution of the pathogenic mechanisms involved, and the lack of curative treatments illustrates the need for the development of interventions to prevent or delay the onset of these aging-related diseases. The present work demonstrates the importance of using age-adapted study models and experimental methods with the goal towards slowing or delaying age-related deleterious processes. Secondly, our results have identified membranes as an essential part for normal brain function. The composition and architectural changes in the neuronal membranes of elderly mice disrupt their functionality and reduce neuroprotective responsiveness such as those sought by anti-Alzheimer’s therapies. We also observed similar pro-aging-type changes in brain membranes of dyslipidemic mice fed a high-fat diet. Thus, disturbances of lipid homeostasis are correlated with an increased risk of developing aging-related cardiovascular and metabolic as well as neurodegenerative diseases. We finally demonstrated the preventive potential of dietary supplementation with docosahexaenoic acid, the most abundant long-chain polyunsaturated fatty acid in the brain, and observed its ability to restore a neuroprotective response that was impaired in older mice