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Sebastien Dupont

Sebastien Dupont
Institut Agro Dijon · UMR Procédés Alimentaires et Microbiologiques

Ph.D

About

52
Publications
8,047
Reads
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1,025
Citations
Citations since 2016
36 Research Items
801 Citations
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2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Introduction
My research deals with the study of the cellular effects of environmental and technological perturbations on microorganisms. The goal of this research is to develop and improve microbiological processes. These processes include production and preservation processes for beneficial microorganisms, and destruction processes for spoilage/pathogenic microorganisms.
Additional affiliations
September 2011 - present
Université de Bourgogne
Education
October 2007 - June 2011
September 2005 - July 2007
University of Burgundy
Field of study
  • Biology
September 2002 - June 2005

Publications

Publications (52)
Article
In this study, we investigated the kinetic and the magnitude of dehydrations on yeast plasma membrane (PM) modifications because this parameter is crucial to cell survival. Functional (permeability) and structural (morphology, ultrastructure, and distribution of the protein Sur7-GFP contained in sterol-rich membrane microdomains) PM modifications w...
Article
The plasma membrane (PM) is a main site of injury during osmotic perturbation. Sterols, major lipids of the PM structure in eukaryotes, are thought to play a role in ensuring the stability of the lipid bilayer during physicochemical perturbations. Here, we investigated the relationship between the nature of PM sterols and resistance of the yeast Sa...
Article
Sterols, essential lipids of most eukaryotic cells, ensure important structural and signaling functions. The selection pressure that has led to different dominant sterols in the three eukaryotic kingdoms remains unknown. Here, we investigated the influence of the progression in the different steps of the ergosterol biosynthetic pathway (EBP) on the...
Article
Yeast cells are well adapted to interfacial habitats, such as the surfaces of soil or plants, where they can resist frequent fluctuations between wet and dry conditions. Saccharomyces cerevisiae is recognized as an anhydrobiotic organism, and it has been the subject of numerous studies that aimed to elucidate this ability. Extensive data have been...
Article
Full-text available
Although the functions and structural roles of sterols have been the subject of numerous studies, the reasons for the diversity of sterols in the different eukaryotic kingdoms remain unclear. It is thought that the specificity of sterols is linked to unidentified supplementary functions that could enable organisms to be better adapted to their envi...
Article
Although fluorescent proteins are widely used as biomarkers (Yin), no study focuses on their influence on the microbial stress response. Here, the Green Fluorescent Protein (GFP) was fused to two proteins of interest in Saccharomyces cerevisiae. Pab1p and Sur7p, respectively involved in stress granules structure and in Can1 membrane domains. These...
Article
Full-text available
The encapsulation of fisetin into S. cerevisiae cells through sonoporation coupled with drying is reported for the first time in the literature. To establish the best conditions to maximize the amount of internalized fisetin, the cell density (5–10% w/v), fisetin concentration (1–3 mg/mL), acoustic energy density (0–333.3 W/L), and drying method (f...
Article
Full-text available
The human intestinal system is a complex of various anaerobes including extremely oxygen-sensitive (EOS) bacteria, some of which have been credited with significant health benefits. Among these, Faecalibacterium prausnitzii, which is one of the most abundant anaerobic bacterial strains in the human intestinal tract, has been proved to be a promisin...
Article
Osmoporation is a novel encapsulation approach for bioactive compounds based on the osmoresistance mechanisms of microbial cells. To the best of our knowledge, this is the first study investigating the production of fisetin-enriched yoghurt using Lactobacillus acidophilus-based bio-capsules via osmoporation as the starter culture. Results showed th...
Article
Full-text available
The objective of this study was to evaluate the performance of Lactobacillus acidophilus cells as a novel encapsulating carrier for fisetin via osmoporation. Initially, the effects of osmotic pressure and initial fisetin concentration on the performance of the osmoporation process were evaluated. The best results were achieved when 15 MPa was appli...
Article
Full-text available
Microbial food spoilage is an important cause of health and economic issues and can occur via resilient contamination of food surfaces. Novel technologies, such as the use of visible light, have seen the light of day to overcome the drawbacks associated with surface disinfection treatments. However, most studies report that photo-inactivation of mi...
Article
Full-text available
Research background. Freeze-drying is the most widely used dehydration process in the food industry for the stabilization of bacteria. Studies have shown the effectiveness of an acid prestress in increasing the resistance of lactic acid bacteria to freeze-drying. Adaptation of bacteria to an acid stress is based on maintaining the properties of the...
Article
Full-text available
Background Stabilization of freeze-dried lactic acid bacteria during long-term storage is challenging for the food industry. Water activity of the lyophilizates is clearly related to the water availability and maintaining a low a w during storage allows to increase bacteria viability. The aim of this study was to achieve a low water activity after...
Article
Although relative air humidity (RH) strongly influences microbial survival, its use for fighting surface pathogens in the food industry has been inadequately considered. We asked whether RH control could destroy Listeria monocytogenes EGDe by envelope damage. The impact of dehydration in phosphate-buffered saline (PBS) at 75%, 68%, 43% and 11% RH o...
Article
Full-text available
Yeasts are anhydrobiotes that accumulate large amounts of trehalose, which is involved in the vitrification of the cytoplasm during drastic desiccation. The effect of devitrification, which can be induced by the transient exposure of desiccated yeasts to increased humidity or elevated temperature, on the survival of yeast has been studied. A glass...
Article
Full-text available
Although mechanisms involved in response of Saccharomyces cerevisiae to osmotic challenge are well described for low and sudden stresses, little is known about how cells respond to a gradual increase of the osmotic pressure (reduced water activity; aw) over several generations as it could encounter during drying in nature or in food processes. Usin...
Article
Anaerobic commensal gut bacteria are among the most promising future treatments for many diseases. Because of their sensitivity to oxygen and to the harsh conditions of the gut, few studies on formulations that deliver bacteria in a viable and functional form to the intestine have been done. The aim of this study was to develop a reliable and easy-...
Patent
Full-text available
The present invention concems a method for eliminating microorganisms present in and/or at the surface of a material to be decontaminated comprising a step of irradiating said material to be decontaminated with radiation consisting of at least two light beams a1and a2 directed onto said material, the two light beams a1 and a2 respectively having a...
Article
Full-text available
Background and objective: Presence of oxygen during production and rehydration of freeze-dried starters and probiotics can decrease viability of the bacteria. Indeed, removal of water from cells during freeze-drying can promote dysfunction in anti-oxidative mechanisms, resulting in oxidative stress by accumulation of reactive oxygen species. The ai...
Article
Full-text available
This study proposes the investigation of curcumin encapsulation into Saccharomyces cerevisiae cells through osmoporation as an efficient way of increasing curcumin stability. The influence of three process parameters (cell, ethanol and curcumin concentrations) on the encapsulation process was evaluated, and the obtained biocapsules were characteris...
Article
Juvenile hormones (JHs) regulate important processes in insects, such as postembryonic development and reproduction. In the hemolymph of Lepidoptera, these lipophilic sesquiterpenic hormones are transported from their site of synthesis to target tissues by high affinity carriers, the juvenile hormone binding proteins (JHBPs). Lepidopteran JHBPs bel...
Article
Full-text available
Green propolis presents a potential source of bioactive compounds, responsible for its antioxidant capacity. The effects of ethanol concentration, solid-solvent ratio, and extraction time were evaluated in regard to the total phenolic content (TPC) and antioxidant capacity of the extracts by the use of central composite rotatable designs. Optimum e...
Article
Full-text available
Blue light (400–430 nm) is known to induce lethal effects in some species of fungi by photo-oxidation caused by the excitation of porphyrins but the mechanisms involved remain poorly understood. In this work, we exposed the yeast Saccharomyces cerevisiae to a high density light flux with two-photon excitation (830 nm equivalent to a one-photon exci...
Data
Evolution of fluorescence intensity in two excitation area (Region of interest: ROI) delimited by a red rectangle. The two ROI are exposed to light stimulation phases of 1.5.104 W/cm2. ROI 1 contains no any yeast cell. ROI 2 contains 1 yeast cell. (A) Photography of the initial photo-oxidation treatment induced by the production of 1O2 and labelled...
Data
Cycle with acquisition phase (4 s, 400 W/cm2) and excitation phase (2 s) at different light powers (1.5.104; 1.7.104; 1.9.104; 2.3.104 and 2.6.104 W/cm2).
Data
Visualization in video (accelerated 60X) of plasma membrane permeabilization and “photo-oxidative burst” for one cell exposed to a light power of 1.5.104 W/cm2 at 830 nm.
Data
Visualization of plasma membrane permeabilization for six cells exposed to a light power of 1.5.104 W/cm2 at 830 nm in the plasma membrane area.
Article
Under natural conditions yeast cells as well as other microorganisms are regularly subjected to the influence of severe drought, which leads to their serious dehydration. The dry seasons are then changed by rains and there is a restoration of normal water potential inside the cells. To survive such seasonal changes a lot of vegetative microbial cel...
Article
Full-text available
Diet quality is critical for animal development and survival. Fungi can provide nutrients that are essential to organisms that are unable to synthetize them, such as ergosterol in Drosophila melanogaster. Drosophila studies examining the influence of yeast quality in the diet have generally either provided the diet over the whole life span (larva t...
Article
Cell osmoporation is a simple and straightforward procedure of creating food‐grade bio‐capsules. This study proposes a new protocol of sequential cell osmoporation stages and evaluates its impact on the efficiency of curcumin and fisetin internalization into Saccharomyces cerevisiae cells. To the best of our knowledge, this is the first report in t...
Article
Faecalibacterium prausnitzii was previously recognized for its intestinal anti-inflammatory activities and it has been shown less abundant in patients with chronic intestinal diseases. However, the main problems encountered in the use of this interesting anaerobic microorganism are firstly its high sensitivity to the oxygen and secondly, its abilit...
Article
Full-text available
Freezing lactic acid bacteria often leads to cell death and loss of technological properties. Our objective was to provide an in-depth characterization of the biophysical properties of the Lactobacillus delbrueckii subsp. bulgaricus membrane in relation to its freeze resistance. Freezing was represented as a combination of cold and osmotic stress....
Article
Full-text available
Osmoporation is an innovative method that can be used with food-grade yeast cells of Saccharomyces cerevisiae as natural encapsulating matrices. This technique overcomes barriers that difficult encapsulation and enables the internalization of fragile bioactive molecules such as fisetin into yeasts. In the present study, we assessed the effects of c...
Article
All cells are delimited by biological membranes, which are consequently a primary target of stress-induced damage. Cold alters membrane functionality by decreasing lipids fluidity and the activity of membrane proteins. In Saccharomyces cerevisiae, evidence links sphingolipid homeostasis and membrane phospholipid asymmetry to the activity of the Ypk...
Article
An original high-pressure microscopy chamber has been designed for real-time visualization of biological cell growth during high isostatic (gas or liquid) pressure treatments up to 200 MPa. This new system is highly flexible allowing cell visualization under a wide range of pressure levels as the thickness and the material of the observation window...
Article
Internalization of hydrophilic molecules into yeast cytosol is required for different applications such as cell transformation or preservation of water soluble components by bioencapsulation. However, these molecules are not able to cross the plasma membrane and strategies have to be developed. Recent works revealed that osmotic perturbations could...
Article
In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containin...
Chapter
La congélation et la déshydratation permettent la conservation de systèmes biologiques sur de longues périodes par le ralentissement des réactions de dégradation cellulaire. Ces opérations impliquent des transferts de chaleur et de masse pouvant conduire à l’altération des structures cellulaires. La maîtrise de la cinétique de ces transferts, asso...
Chapter
L’eau est un élément indispensable à la structure et aux activités des microorganismes, qu’ils soient procaryotes (bactéries) ou eucaryotes (champignons). La plupart sont adaptés aux fluctuations hydriques de leur environnement et disposent d’un arsenal métabolique qui leur permet de compenser les effets de la déshydratation, au moins lorsqu’elle e...
Article
The plasma membrane (PM) is a key structure for the survival of cells during dehydration. In this study, we focused on the concomitant changes in survival and in the lateral organization of the PM in yeast strains during desiccation, a natural or technological environmental perturbation that involves transition from a liquid to a solid medium. To e...
Book
Sterols are essential lipids of most eukaryotic cells and ensure important structural and signaling functions. They are represented by cholesterol in vertebrates, phytosterols in plants, and ergosterol in fungi. The specificity of sterols, in each eukaryotic kingdom, could be related to biological evolution but the origin of the differentiation rem...
Conference Paper
Full-text available
Preservation of microorganisms by desiccation is a major industrial interest. However, study of cell survival mechanisms that occur during desiccation is complex. In this work, the impact of the magnitude and the kinetics of dehydration on yeast survival were evaluated in either hyperosmotic liquid medium or a gaseous environment. A same lethal mag...
Thesis
Full-text available
Preservation of microorganisms of interest (ferments, probiotics) in dry form is widespread in the industry. However, the dehydration processes lead to variable survival rates according to the group, species and strain of microorganism considered, but also according to the type of process used (drying, freeze drying, freezing). The plasma membrane...
Article
The plasma membrane (PM) is a main site of injury during osmotic perturbation. Sterols, major lipids of the PM structure in eukaryotes, are thought to play a role in ensuring the stability of the lipid bilayer during physicochemical perturbations. Here, we investigated the relationship between the nature of PM sterols and resistance of the yeast Sa...
Article
Exposure of pancreatic β cells to long-chain saturated fatty acids (SFA) induces a so-called endoplasmic reticulum (ER) stress that can ultimately lead to cell death. This process is believed to participate in insulin deficiency associated with type 2 diabetes, via a decrease in β-cell mass. By contrast, some unsaturated fatty acid species appear l...
Article
Full-text available
Stress within the endoplasmic reticulum (ER) induces a coordinated response, namely the unfolded protein response (UPR), devoted to helping the ER cope with the accumulation of misfolded proteins. Failure of the UPR plays an important role in several human diseases. Recent studies report that intracellular accumulation of saturated fatty acids (SFA...

Questions

Question (1)
Question
Hello everyone,
I am working on the different systems involved in the protection of phospholipids against oxidation. Tocopherol is one of the most efficient hydrophobic antioxidant that we can found in plasma membrane of plant cells. However, I did not find information about its concentration (or phospholipids/tocopherol molar ratio) in plant cell membranes. Does anyone have this information or could advise me some articles about it?
Thanks in advance.

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Projects

Projects (5)
Project
L’objectif principal du projet EFFINOX est de caractériser les effets non-intentionnels de traitements photo-oxydatifs induits par la lumière visible et de déterminer les modalités d’application limitant ces effets en vue du développement de cette technologie comme alternative aux intrants chimiques en protection des cultures et dans la transformation alimentaire. Cette technologie innovante et brevetée par l’UMR PAM a montré son potentiel contre des microorganismes fongiques d’altération et phytopathogènes. Dans ce projet, les altérations physico-chimiques et les réponses physiologiques et métaboliques des matrices traitées (semences, vignes et vin) ainsi que les modifications des communautés microbiennes présentes seront évaluées. La méconnaissance de ces effets constitue actuellement un risque important pour le développement de cette technologie. Au cours du projet, différentes modalités (utilisation de flashs lumineux, rétrécissement du spectre lumineux utilisé, combinaison avec des agents de bioprotection) seront évaluées pour leur capacité à diminuer ces effets non-intentionnels. Les modalités permettant de limiter ces effets sans diminuer l’efficacité des traitements photo-oxydatifs seront retenues. Les fournisseurs de solutions lumineuses peu énergétiques et/ou les entreprises d’agroéquipements de la filière agricole et viti-vinicole pourront ainsi bénéficier d’un cahier des charges afin de développer, à grande échelle, des équipements de traitements physiques répondant à des objectifs environnementaux et économiques nécessaires à la transition agroécologique. Les travaux de ce projet font l’objet d’un financement de la part des Carnot Qualiment® et Plant2Pro®, supportés par l’ANR (conventions n° : 0026 01 et n° : 0024 01), dans le cadre de leur appel à projets ressourcement scientifique 2021.
Project
Use of LED technology to develop intense light emitter centered in the near UV band and increase the efficiency of antimicrobial light treatments.
Project
The presence of microorganisms (fungi and bacteria) on the surface of food raw materials is causing a significant loss of agricultural production for human consumption. The main solution currently available is the massive use of fungicides and bactericides on fruits, vegetables, and surfaces and in wash waters of food raw materials. However, this solution leads to environmental and toxicological issues. The GreenDeconta project proposes to characterize microbial responses of spoilage microorganisms to physical perturbations in order to develop a sustainable microbial decontamination process. These perturbations consist in using useful wavelengths of visible light (inducing specific photo-oxidation) in combination with moisture variations. The dynamic and the localization of cellular damage will be studied during these perturbations. This knowledge will be used for the future development of a reasoned decontamination process that could be applied on different food matrixes and on surfaces of food (process) environment.