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Accueil > Pages Perso > Serge Michalet

Equipe de Recherche Multi-résistance environnementale et efflux bactérien

Serge Michalet

Maître de conférences

Activité

  • Thèmes de recherches :
    1. Multi-Drug Resistance
    2. Chemical Ecology : plant-microbes interactions

Chimie des substances naturelles ; chimiobiodiversité ; métabolites secondaires et interactions biotiques ; modulation de la MultiDrug Résistance ; substances naturelles bioactives.

Parcours scientifique

  • Pharm D
  • Ph D

Enseignement/Encadrement

  • Maître de Conférences en Pharmacognosie à l’Institut des Sciences Pharmaceutiques et Biologiques de Lyon (UCB Lyon1) dans l’UMR-5557 CNRS/UCB : Ecologie Microbienne
  • Pharmacognosie, Biologie Végétale, Botanique, Phytothérapie dans le cursus de Pharmacie (ISPB – UCB Lyon 1). Encadrement et jury de stage du master Phytoressources (Département de Biologie – UCB Lyon1)

Publications

2017



  • El Moujahid L, et al. 2017. Effect of plant diversity on the diversity of soil organic compounds. PLOS ONE. 12:e0170494. doi: 10.1371/journal.pone.0170494.
    Résumé : The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms.
    Mots-clés : #5, #cesn, Biodiversity, Edaphology, Medicinal plants, Organic acids, Organic compounds, Phenols, Plants, Species diversity.


  • Guyonnet JP, et al. 2017. The effects of plant nutritional strategy on soil microbial denitrification activity through rhizosphere primary metabolites. FEMS Microbiology Ecology. 93. doi: 10.1093/femsec/fix022.
    Mots-clés : #3, #5.


  • Michalet S, et al. 2017. Tolerance of Japanese knotweed s.l. to soil artificial polymetallic pollution: early metabolic responses and performance during vegetative multiplication. Environmental Science and Pollution Research. 1-11. doi: 10.1007/s11356-017-9716-8.
    Résumé : The expansion of invasive Japanese knotweed s.l. is of particular concern because of its aptitudes to rapidly colonize diverse environments, especially anthropized habitats generally characterized by their pollution with heavy metals. Whether the presence of heavy metals impacts the performance traits of this plant is a central question to better understand its invasive properties, though no controlled approach to assess these effects was yet reported. In this aim, we undertook greenhouse experiments where rhizome fragments of Japanese knotweed s.l. (Fallopia japonica and Fallopia × bohemica) were grown during 1 and 3 months, in a soil pot artificially polluted or not with heavy metals added in mixture (Cd, Cr, Pb, Zn). Our results showed that (i) the presence of heavy metals delayed rhizome regeneration and induced lowered plant part weights but did not affect plant height after 3 months; (ii) the effect of metals on the metabolic profiles of belowground part extracts was only detectable after 1 month and not after 3 months of growth, though it was possible to highlight the effect of metals independently of time and genotype for root extracts, and torosachrysone seemed to be the most induced compound; and (iii) the hybrid genotype tested was able to accumulate relatively high concentrations of metals, over or close to the highest reported ones for this plant for Cr, Cd and Zn, whereas Pb was not accumulated. These findings evidence that the presence of heavy metals in soil has a low impact on Fallopia sp. overall performance traits during rhizome regeneration, and has a rather stimulating effect on plant growth depending on pollution level.
    Mots-clés : #8, #cesn.

2016



  • Lebot V, Michalet S, Legendre L. 2016. Identification and quantification of phenolic compounds responsible for the antioxidant activity of sweet potatoes with different flesh colours using high performance thin layer chromatography (HPTLC). Journal of Food Composition and Analysis. 49:94-101. doi: 10.1016/j.jfca.2016.04.009.
    Résumé : The objectives of the present study were to develop a simple high performance thin layer chromatography (HPTLC)-based protocol: (i) to allow high-throughput profiling of phenolic compounds of microwaved roots from 295 sweet potato varieties and breeding lines, (ii) to quantify the content of anthocyanins and caffeoylquinic acid (CQA) derivatives, and (iii) to determine their respective contributions to the antioxidant activity of sweet potato methanolic extracts using the DPPH test. Analysed accessions were separated into three groups: white-fleshed (n = 100), orange-fleshed (n = 64) and purple-fleshed (n = 131). Purple-fleshed accessions presented the highest mean CQA content. After DPPH treatment and transmittance scanning of the plate at 517 nm, the most active free radical scavengers were found to be the four CQAs (CGA, 3,4-, 4,5- and 3,5-diCQA) while the anthocyanins were found to be less active. The total antioxidant capacity of the sweet potato methanolic extracts was mostly linked to total CQAs content. This method can now be used for fast routine analysis and selection of sweet potato breeding clones.
    Mots-clés : #3, #8, #cesn, Antioxidant activity evaluation, DPPH image analysis, Food analysis, Food composition, HPTLC fingerprinting, Ipomoea batatas, Method validation, Sweet potato.


  • Muñoz-Cuervo I, Malapa R, Michalet S, Lebot V, Legendre L. 2016. Secondary metabolite diversity in taro, Colocasia esculenta (L.) Schott, corms. Journal of Food Composition and Analysis. 52:24-32. doi: 10.1016/j.jfca.2016.07.004.
    Résumé : Taro, Colocasia esculenta (L.) Schott, is one of the oldest major staple food crops of tropical regions. This study represents one the first in-depth surveys of taro biodiversity based on corms flesh secondary metabolites fingerprints. Out of the 167 analyzed cultivars, 70 UV-absorbing substances were annotated according to their retention time, UV/Vis absorption spectrum, high resolution mass (by HRMS) and fragmentation pattern (tandem MS-MS). They included 6 carotenoids, 35 flavones/flavonols, 6 flavanones, 2 flavanols and 1 indol. Twenty flavones that were glycosylated forms of apigenin, luteolin and chrysoeriol conferred to the corms a yellow color and defined a low abundance (ca. 10% of cultivars) chemotype. Their accumulation negatively correlated with flavanones which were annotated for the first time in taro. Orange flesh corms were characterized by high levels of β-carotene. Secondary metabolite-based chemotypes displayed no geographical distribution pattern.
    Mots-clés : #3, #cesn, Araceae, Carotenoids, Chemotype, Colocasia esculenta, Diversity, Food analysis, Food composition, HPLC, Phenolic compounds, Taro, UPLC-ESI-Q-TOF.

2015



  • Chaabane F, et al. 2015. In vitro and in vivo anti-melanoma effects of Daphne gnidium aqueous extract via activation of the immune system. Tumor Biology. doi: 10.1007/s13277-015-4492-x.
    Mots-clés : #8, #cesn.

  • Chahad AM, et al. 2015. Medicinal Plants from the Ouaddaï Province (Chad): An Ethnobotanical Survey of Plants Used in Traditional Medicine. Journal of Alternative and Complementary Medicine (New York, N.Y.). 21:569-577. doi: 10.1089/acm.2014.0243.
    Résumé : BACKGROUND/OBJECTIVE: Plants are the basis of all health care systems. This study sought to inventory the most used medicinal plants in the local therapeutic patrimony of the Ouaddaï (East Chad) through an ethnobotanical investigation. METHODS: The inventory described the plant parts used, their mode of preparation, and their therapeutic uses. RESULTS: Thirty-eight plants species are used for different purposes and diseases. The most used species belongs to the Mimosaceae (eight species), Caesalpiniaceae (four species), and Combretaceae (four species) families. The traditional medicinal uses, as well as the preparations, of these plants are diverse. The used parts are leaves (36.4%), peels (23.7%), fruits (18.2%), roots (10.9%), stems (5.5%), and other (5.3%). These plants are used to treat 16 different illnesses, notably amoebiasis (26.8%), respiratory infections (14.3%), fever (12.5%), kidney stones (7.1%), snake bites (7.1%), tooth decay (5.4%), and leprosy (5.4%). CONCLUSION: The results obtained from this survey constitute the starting point of an inventory of local medicinal plants to be completed by phytochemical, pharmacologic, and toxicologic studies to allow good exploitation of the local medicinal flora.
    Mots-clés : #8, #cesn, Chad, Combretaceae, Ethnobotany, Fabaceae, Medicine, African Traditional, Plants, Medicinal.


  • Lebot V, Lawac F, Michalet S, Legendre L. 2015. Characterization of taro [Colocasia esculenta (L.) Schott] germplasm for improved flavonoid composition and content. Plant Genetic Resources. 1-9. doi: 10.1017/S1479262115000581.
    Mots-clés : #3, #8, #cesn.

2013



  • Michalet S, et al. 2013. Phytochemical analysis of mature tree root exudates <i>in situ</i> and their role in shaping soil microbial communities in relation to tree N-acquisition strategy. Plant Physiology and Biochemistry. 72:169-177. doi: 10.1016/j.plaphy.2013.05.003.
    Résumé : Abstract Eperua falcata (Aublet), a late-successional species in tropical rainforest and one of the most abundant tree in French Guiana, has developed an original strategy concerning N-acquisition by largely preferring nitrate, rather than ammonium [1].Given the preference of this species for nitrate, we hypothesized that root exudates would promote nitrate availability by a) enhancing nitrate production by stimulating ammonium oxidation or b) minimizing nitrate losses by inhibiting denitrification. Root exudates were collected in situ in monospecific planted plots. The phytochemical analysis of these exudates and of several of their corresponding root extracts was achieved using UHPLC/DAD/ESI-QTOF and allowed the identification of diverse secondary metabolites belonging to the flavonoid family. Our results show that (i) the distinct exudation patterns observed are related to distinct root morphologies, and this was associated with a shift in the root flavonoid content, (ii) a root extract representative of the diverse compounds detected in roots showed a significant and selective metabolic inhibition of isolated denitrifiers in vitro, and (iii) in soil plots the abundance of nirK-type denitrifiers was negatively affected in rhizosphere soil compared to bulk. Altogether this led us to formulate hypothesis concerning the ecological role of the identified compounds in relation to N-acquisition strategy of this species.
    Mots-clés : #3, #5, #8, #cesn, Chemical Ecology, Denitrification, Eperua falcata, Flavonoids, Metabolic Profiling, Mycorrhizae, Plant-Microbes Interactions, Root Exudates.


  • Rakotomalala G, et al. 2013. Extract from Mimosa pigra attenuates chronic experimental pulmonary hypertension. Journal of Ethnopharmacology. 148:106-116. doi: 10.1016/j.jep.2013.03.075.
    Résumé : AbstractEthnopharmacological relevance Different parts of Mimosa pigra (MPG) are used in traditional medicine in Madagascar, tropical Africa, South America and Indonesia for various troubles including cardiovascular disorders. Aim of the study To investigate the mechanisms underlying the vascular effects of MPG by assessing in vitro its antioxidant and anti-inflammatory properties, and its vascular relaxing effects, and in vivo, its action on hypoxic pulmonary hypertension (PAH) in rats. Material and methods The antioxidant activity of MPG leaf hydromethanolic extract was determined by using both the 1,1-diphenyl-2-picrylhydrazyl radical scavenging and the oxygen radical absorbance capacity in vitro assays. Anti-inflammatory properties were assayed on TNFα-induced VCAM-1 expression in endothelial cells. The vasorelaxant effect of MPG extract was studied on rat arterial rings pre-contracted with phenylephrine (1 μM) in the presence or absence of the endothelium. In vivo MPG extract effects were analyzed in chronic hypoxic PAH, obtained by housing male Wistar rats, orally treated or not with MPG extract (400 mg/kg/d), in a hypobaric chamber for 21 days. Results MPG leaf extract had antioxidant and anti-inflammatory properties. It induced endothelium-dependent, NO-mediated relaxation of rat aorta and pulmonary artery. In vivo, chronic MPG treatment reduced hypoxic PAH in rat by decreasing by 22.3% the pulmonary arterial pressure and by 20.0% and 23.9% the pulmonary artery and cardiac remodelling, respectively. This effect was associated with a restoration of endothelium function and a 2.3-fold increase in endothelial NO synthase phosphorylation. MPG leaf hydromethanolic extract contained tryptophan and flavonoids, including quercetin glycosides. Both compounds also efficiently limit hypoxia-induced PAH. Conclusions Our results show endothelial protective action of MPG leaf hydromethanolic extract which is likely to be due to its antioxidant action. MPG successfully attenuated the development of PAH, thus demonstrating the protective effect of MPG on cardiovascular diseases.
    Mots-clés : #3, #8, #cesn, Anti-inflammatory, Anti-oxidant, Arterial pressure, Artery, Endothelium.

2011



  • Zaabat N, et al. 2011. Antioxidant and antigenotoxic properties of compounds isolated from <i>Marrubium deserti</i> de Noé. Food and Chemical Toxicology. 49:3328-3335. doi: 10.1016/j.fct.2011.08.026.
    Mots-clés : #1, #4, #5, #6, #8, #cesn.

2010

  • Zaabat N, et al. 2010. Preliminary study of Marrubium deserti de Noe, an endemic Algerian Lamiaceae. Phytotherapie. 8:353-358.
    Mots-clés : #8, #cesn.


  • Zaabat N, et al. 2010. Étude préliminaire de <i>Marrubium deserti</i> de Noé, une Lamiaceae endémique algérienne. Phytothérapie. 8:353-358. doi: 10.1007/s10298-010-0589-y.
    Résumé : Connue pour ses propriétés médicinales, aromatiques ou culinaires, la famille des Lamiacées présente un intérêt économique majeur, notamment comme source d’huiles essentielles. Dans le cadre de l’étude de la biodiversité de la flore algérienne, l’analyse phytochimique et la recherche des activités biologiques des parties aériennes de Marrubium deserti de Noé ont été entreprises. L’extraction par des solvants de polarité croissante tels que le dichlorométhane, l’acétate d’éthyle et le butanol, puis la purification des extraits obtenus ont permis d’isoler et d’identifier à ce jour un diterpène original de type labdane, un flavonoïde et des phénylpropanoïdes glycosylés. Les extraits et les composés isolés ont fait l’objet d’une étude biologique comme antioxydants, antibactériens et antigénotoxiques. Known for its medicinal, aromatic or culinary properties, the Lamiaceae family represents a major economic interest, in particular as a source of essential oils. The purpose of this research concerns the phytochemical and the biological study of one of the Algerian flora’s medicinal plants known as Marrubium deserti de Noé. The extraction by solvents of increasing polarity: dichloromethane, ethyl acetate and butanol led to the isolation and identification of a novel labdane-type diterpene, a flavonoid and phenylpropanoid glycosides. Extracts and pure compounds were tested as antioxidant, antibacterial as well as antigenotoxic.
    Mots-clés : #4, #5, #6, #8, #cesn, Antibacterial, Antibactériens, Antigenotoxic, Antigénotoxiques, Antioxydant, Antioxydants, Complementary & Alternative Medicine, Marrubium deserti, medicine, Medicine/Public Health, general.

2008



  • Michalet S, Mariotte AM, Gibbons S, Dijoux-Franca MG. 2008. Use of Efflux Pump Inhibitors (EPIs) to overcome bacterial Multi-Drug Resistance (MDR): plants as a source of chemodiversity and their adaptive response toward bacterial stress. Planta Medica. 74. doi: 10.1055/s-0028-1083948.
    Mots-clés : #5, #6, #8, #cesn.


  • Michalet S, et al. 2008. New Components Including Cyclopeptides from Barks of Christiana africana DC. (<i>Tiliaceae</i>). Helvetica Chimica Acta. 91:1106-1117. doi: 10.1002/hlca.200890118.
    Mots-clés : #5, #6, #8, #cesn.


  • Oughlissi-Dehak K, et al. 2008. Sesquiterpenes from aerial parts of <i>Ferula vesceritensis</i>. Phytochemistry. 69:1933-1938. doi: 10.1016/j.phytochem.2008.03.010.
    Mots-clés : #5, #8, #cesn.

Chapitre d’ouvrages

2009


  • Michalet S, Dijoux-Franca MG. 2009. ABC Transporters and Resistance to Antibiotics. In: ABC Proteins and Multidrug Resistance. John Wiley & Sons p. .
    Mots-clés : #8, #cesn.

Article de journal

2008


  • Doléans-Jordheim A, et al. 2008. Les phénomènes de résistance aux antibiotiques liés aux pompes à efflux: exemple de <i>Staphylococcus aureus</i>. Annales de Biologie Clinique http://www.jle.com/fr/revues/bio_rech/abc/e-docs/00/04/41/89/resume.phtml.
    Mots-clés : #6, #8, #cesn.

Vulgarisation

Communications Orales

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