Alimentation

Résumé

L’alimentation est le choix et l'intégration de la nourriture (ensemble d'aliments) par un être vivant. Une fois les aliments choisis et intégrés (par exemple par ingestion), les processus de nutrition permettent à l'organisme de survivre et de fonctionner. Chez l'humain, l'alimentation caractérise aussi la manière de récolter, stocker et préparer les aliments, de le cuisiner et de s'alimenter, qui s'intéresse davantage au domaine culturel, social et éthique voire du religieux (tabous alimentaires, jeûne, rituels de préparation, etc.). Nutrition Nutrition Approche thermobiologique Les réactions chimiques exothermiques nécessaires à la vie sont dépendantes d'apports en nutriments. Chez les organismes supérieurs, ceux-ci sont soit synthétisés par photosynthèse (végétaux), soit puisés dans des composés organiques (animaux et champignons). Il existe d'autres sources énergétiques pour les micro-organismes : par exemple, certaines archées puisent leur énergie en pr

Source officielle

https://fr.wikipedia.org/wiki/Alimentation

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Séances de cours associées (6)

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Peptone Supplementation of Culture Medium Has Variable Effects on the Productivity of CHO Cells

Lucia Baldi Unser, Fatemeh Davami, Yashas Rajendra, Florian Maria Wurm

The optimization of cell culture conditions for growth and productivity of recombinant Chinese hamster ovary (CHO) cells is a critical step in biopharmaceutical manufacturing. In the present study, the effects of the timing and amount of peptone feeding of a recombinant CHO cell line grown in a basal medium in serum-free suspension culture were determined for eight peptones of different origin (plant and casein). The amino acid content and the average molecular weight of the peptones chosen were available. In optimized feeding strategies with single peptones, increase 100 % volumetric productivity and 40 % in cell number were achieved. In feeding strategies with two peptones, several combinations stimulated protein productivity more than either peptone alone, depending on the peptone concentration and time of feeding. Some peptones, which did not stimulate productivity when added alone proved to be effective when used in combination. The combined peptones feeding strategies were more effective with peptones of different origin. Our data support the notion that the origin of peptones provides some guidance in identifying the most effective feeding strategies for recombinant CHO cells.

2014

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Effect of temperature and feeding on carbon budgets and O2 dynamics in Pocillopora damicornis

Niclas Heidelberg Lyndby

Studying carbon dynamics in the coral holobiont provides essential knowledge of nutritional strategies and is thus central to understanding coral ecophysiology. In this study, we assessed the carbon budget in Pocillopora damicornis (usingH13CO3) as a function of feeding status and temperature stress. We also compared dissolved oxygen (O2) fluxes measured at the colony scale and at the polyp scale. At both scales, O2 production rates were enhanced for fed vs. unfed corals, and unfed corals exhibited higher bleaching and reduced photosynthetic activity at high temperature. Unfed corals exclusively respired autotrophically acquired carbon, while fed corals mostly respired heterotrophically acquired carbon. As a consequence, fed corals excreted on average >5 times more organic carbon than unfed corals. Photosynthate translocation was higher under thermal stress, but most of the carbon was lost via respiration and/or mucus release (42−46% and 57−75% of the fixed carbon for unfed and fed corals, respectively). Such high loss of translocated carbon, coupled to low assimilation rates in the coral tissue and symbionts, suggests that P. dami - cornis was nitrogen and/or phosphorus limited. Heterotrophy might thus cover a larger portion of the nutritional demand for P. damicornis than previously assumed. Our results suggest that active feeding plays a fundamental role in metabolic dynamics and bleaching susceptibility of corals.

2020

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When studying the drug effectiveness towards a target model, one should distinguish the effects of the drug itself and of all the other factors that could influence the screening outcome. This comprehensive knowledge is crucial, especially when model organisms are used to study the drug effect at a systemic level, as a higher number of factors can influence the drug-testing outcome. Covering the entire experimental domain and studying the effect of the simultaneous change in several factors would require numerous experiments, which are costly and time-consuming. Therefore, a design of experiment (DoE) approach in drug-testing is emerging as a robust and efficient method to reduce the use of resources, while maximizing the knowledge of the process. Here, we used a 3-factor-Doehlert DoE to characterize the concentration-dependent effect of the drug doxycycline on the development duration of the nematode Caenorhabditis elegans. To cover the experimental space, 13 experiments were designed and performed, where different doxycycline concentrations were tested, while also varying the temperature and the food amount, which are known to influence the duration of C. elegans development. A microfluidic platform was designed to isolate and culture C. elegans larvae, while testing the doxycycline effect with full control of temperature and feeding over the entire development. Our approach allowed predicting the doxycycline effect on C. elegans development in the complete drug concentration/temperature/feeding experimental space, maximizing the understanding of the effect of this antibiotic on the C. elegans development and paving the way towards a standardized and optimized drug-testing process.

2018

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