Dissertations / Theses on the topic 'Propriétés antimicrobiennes'
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Thiebault, Nicolas. "Propriétés antimicrobiennes et anti-inflammatoires de saccharides : étude structure / activité." Amiens, 2008. http://www.theses.fr/2008AMIE0100.
The aim of this work was to synthesize and characterize the carbohydrates derivatives modified in anomeric position or in primary position regioselectively. In the first time, a regioselective disubstitution of maltotriose (DP3) was carried out and optimized in only one step giving a key intermediary to the accesses of dialkylmaltotriosides derivatives. Then, we carried out the synthesis of S-alkylglycosides and O-alkylglycosides modified in anomeric position, with good yields, in order to undertake a study structure/activity. In the second time, we evaluated the antimicrobial properties of all these compounds. We observed that the S-alkylglycosides derivatives exhibit weak or no activity whereas the O-alkylmaltodextrines compounds alone or in mixture showed interesting antimicrobial activities. In the third time, an evaluation of the anti-inflammatory drug activity of all these compounds was carried out. Once again, the S-alkylglycosides derivatives presented weak or no activity, while the O-alkylmaltodextrines derivatives alone showed significative anti-inflammatory drug activities. Moreover, mixtures of the latter led to a synergy of action on the inhibition of IL8 never yet described in the literature
Mandoukou, Landry. "Etude des propriétés antimicrobiennes d'ologosaccharides cycliques naturels et fonctionnalisés : les cyclodextrines." Amiens, 2006. http://www.theses.fr/2006AMIE0609.
Poupet, Cyril. "Caractérisation in vivo des propriétés antimicrobiennes de la souche probiotique Lcr35®." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC008.
Antibiotics and antifungals are one of the greatest discoveries of medicine and have helped save millions of lives. However, their effectiveness is threatened by the adaptation of microorganisms that become resistant. This phenomenon is particularly related to the abnormally high consumption of antimicrobial molecules, especially in France. Even though these resistances are mainly acquired by bacteria, pathogenic yeasts such as the genus Candida do not escape the rule. Therefore, the scientific community and health services must implement as soon as possible alternatives to traditional drugs. Among these alternatives, the use of probiotic microorganisms whose antifungal potential has already been demonstrated using preclinical models (cell cultures, laboratory animals) and clinical studies is particularly promising. This is the case of the Live Biotherapeutic Microorganism Lactobacillus rhamnosus Lcr35® strain whose anti-C. albicans has been demonstrated in previous work but failed to describe the mechanisms of action. Understanding them has become a strategic need for the development of new treatments for humans.An innovative experimental approach, using the nematode model Caenorhabditis elegans, has been implemented. The aim was to simulate a fungal infection and treat it with Lcr35® using preventive and curative approaches. These were followed by means of tests of longevity and survival of the host, by the study of its transcriptome (in a targeted and global way), all in connection with the follow-up of the activity of a factor transcription, DAF-16. We thus demonstrated that Lcr35® induced a significantly increased survival of the host, including after infection by Candida. The analysis of the transcriptome of C. elegans and the use of mutant strains showed the involvement of the p38 MAPK and DAF-2 / DAF-16 signaling pathways, pathways involved in longevity and pathogen control. Also, in vitro Caco-2 intestinal cell assays showed significant inhibition of pathogen growth and adhesion by Lcr35®. These results suggest that the bacterium Lcr35® has a direct action on the pathogen causing its death but also by modulating the transcriptional response of the host via highly conserved signaling pathways. Further study, targeting the host metabolome, would allow a better understanding of the mechanisms and adapt the industrial design of LBM according to the therapeutic target
Baixe, Sébastien. "Développement d’un hydrogel injectable à propriétés antimicrobiennes pour la prévention des péri-implantites." Thesis, Strasbourg, 2019. https://publication-theses.unistra.fr/restreint/theses_doctorat/2019/Baixe_Sebastien_2019_ED182.pdf.
Periimplant diseases are an oral infection caused by bacteria, especially P. gingivalis that is a periodontal pathogen involved in inflammatory response, leading to a destruction of implant-supporting tissues (periimplantitis). Currently, effective treatments consist in surgical techniques with systemic broad-spectrum antibiotics and antiseptics. Nevertheless, these therapies may fail because of the hollow spaces in the implant-abutment connection, that are completely contaminated by bacteria in proximity of soft tissues. For our experiment, we have chosen an alginate-catechol-based gel at 1% (for an easy manipulation), that is bioinspired from the system of adhesion of marine mussels’ pads. Physicochemical framework of this gel in wet conditions are tunable with an oral application. We show that AC 1% is stable for one month in PBS at 37°C. Gelation kinetics is rapid (under one minute) and reproducible in rheometer assays. Tacking tests highlight good adhesive results on metal and soft tissues. AC 1% can be combinate with pluronic bisSH 18% to provide a gel with better physicochemical properties. D-CTL is a natural antimicrobial peptide with a Dextrogyre conformation (D-CTL) that is more efficient, without bacterial resistance. CTL mixed to the gel strengths its mechanical properties and has a bactericide activity against P. gingivalis, E. coli et C. albicans. Between 1 and 10 % of the peptide initially introduced in gel are released. HPLC and mass spectrometer indicate that most of the fragments are conserved in the active site of D-CTL and remain efficient. Biocompatibility tests on human fibroblast show results closed to 100%. Gels are assessed in vitro on implant/abutment assemblies put in sealing boxes. Bacteria colonize microgaps between implant and abutment, abutment and crown and its rough surfaces, but are shown to stop at the interface with gel. AC 1%+ D-CTL is a promising candidate for a dental implant application
Marcillaud, Laurence. "Etude des propriétés antimicrobiennes d'un extrait végétal : applications dans les domaines viticole et œnologique." Bordeaux 2, 1998. http://www.theses.fr/1998BOR20632.
Barakat, Rana. "Etude des propriétés biologiques et antimicrobiennes de la pyocyanine, pigment redox-actif produit par Pseudomonas aeruginosa." Phd thesis, Université de La Rochelle, 2012. http://tel.archives-ouvertes.fr/tel-00825873.
Batdorj, Batjargal. "Les produits laitiers mongols, source de bactéries lactiques aux propriétés antimicrobiennes : identification, purification, caractérisation et application." Nantes, 2006. http://www.theses.fr/2006NANT2042.
Two lactic acid bacteria were isolated from mongolian traditional fermented dairy products. They show a strong antimicrobial activity against some food-born pathogens. They were identified on the basis of their morphological, biochemical and molecular biological characteristics. Enterococcus durans A5-11 was isolated from mongolian airag. A three-step purification procedure was developed to separate two bacteriocins with molecular mass of 5206 and 5218 Da, respectively. They are thermostable and not sensitive to acid and alkaline conditions. E. Durans A5-11 shows antifungal properties during its growth on defatted sunflower meal. Lactobacillus delbrueckii subsp. Lactis T31 producing 5 mM/l H2O2 was isolated from mongolian yoghurt. A significant decrease of pathogens was observed in mixed cultures of L. Delbrueckii subsp. Lactis T31 with either E. Coli or L. Innocua
Vandekerckove, Pascal. "Pouvoir antiseptique de celluloses fonctionnalisées par des ammoniums quaternaires : applications au développement d'un nouveau "biotextile" à propriétés antimicrobiennes." Lille 1, 1986. http://www.theses.fr/1986LIL10169.
Naigre, Ruth. "Carbonylation asymétrique de monoterpènes catalysée par des complexes du Palladium en vue d'obtenir des propriétés antimicrobiennes et phytosanitaires." Toulouse, INPT, 1994. http://www.theses.fr/1994INPT043G.
Moulari, Brice. "Propriétés antimicrobiennes in vitro d'extraits de deux plantes africaines : rôle de l'astilbine : potentialisation du pouvoir antibactérien par nanoencapsulation." Besançon, 2005. http://www.theses.fr/2005BESA3004.
The increasingly frequent emergence of fungal and bacterial strains resistant to classical antimicrobial agents, contributes to significantly amplify the gravity of the fungal and bacterial infections. Limitations of synthesized compounds in the treatment of chronic diseases require the development of new molecules. So, the plants represent an interesting and cheaper alternative. Ln the course of the study of medicinal plants from Africa, Cassytha filiformis L. (Lauraceae) and Harungana madagascariensis Lam. Ex Pair. (Hypericaceae), two plants largely used in African traditional medicine, were investigated. We carried out in vitro antimicrobials screening of the extracts of two plants against human pathogenic fungi and cutaneous bacteria. The different MIC [minimal inhibitive concentrations] were determined. The ethyl acetate extract of the leaves of Harungana madagascariensis was found to display interesting antibacterial properties against saprophytic cutaneous bacteria. Based on this screening, a detailed investigation of the ethyl acetate leaves extract was realised. Subsequently, the bacteriostatic and the bactericidal activities of this extract against cutaneous and oral bacteria were determined. Ln addition, this extract was fractionated and the fractions were tested against bacteria by bioautographic method. The bioactive compound was purified, isolated and identified by chromatographic and spectroscopic techniques, as a flavanone : astilbin. Finally, the in vitro potentialization of the antibacterial activity of the ethanolic and ethyl acetate leaf extracts of Harungana madagascariensis was obtained using PLGA-nanoparticles (PLGA = poly d,I-lactide-co-glycolide acid)
Merck, Florence. "La biodiversité végétale au service des ingrédients naturels : étude des propriétés antimicrobiennes et antioxydantes d’extraits végétaux et développement d’un conservateur naturel pour l’industrie cosmétique." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4118/document.
This PhD thesis is part of the NATUBAVAL project that aims at discovering new natural preservatives for the cosmetics industry, issued from one of the world’s biodiversity hotspots: the Mediterranean Basin. Seventeen plant extracts were obtained and screened for their antimicrobial properties against Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus brasiliensis and Candida albicans and their antioxidant capacity. Santolina chamaecyparissus extract was found to present superior properties and selected for further investigation. A bioguided fractionation permitted to isolate the major compound of the most active fraction, that was identified as the active compound, a known spiroketal enol from the polyacetylenes family. An optimization of the crude extract of interest was then performed in order to maximize its activity and to face the challenge of an industrial scale-up and its incorporation in a cosmetic formulation. Finally, this study introduces a natural ingredient development strategy that might potentially be used as an alternative to synthetic preservatives in cosmetics
Nyegue, Maximilienne Ascension. "Propriétés chimiques et biologiques des huiles essentielles de quelques plantes aromatiques et/ou médicinales du Cameroun : évaluation de leurs activités antiradiculaires, anti-inflammatoires et antimicrobiennes." Montpellier 2, 2006. http://www.theses.fr/2006MON20010.
Briolat, Jenny. "Nouvelles données en neuroimmunoendocrinologie : Effets des rythmes biologiques sur l'activité antibactérienne de l'ubiquitine sécrétée.Caractérisation des propriétés antimicrobiennes de la cateslytine, un peptide multifonctionnel dérivé de la chromogranine A." Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13045.
Cai, Zhiwei. "Nouveaux matériaux à base de polyoxotitanates (POTs) dopé ou à base de complexe salicylate de titane (IV) et d'argent (I)." Electronic Thesis or Diss., Strasbourg, 2023. http://www.theses.fr/2023STRAF062.
In recent years, titanium dioxide has attracted much attention as a highly stable material with a wide range of applications from white pigment to its applications as a semiconductor or advanced photonic devices. Using recently developed synthetic approaches, the synthesis of atomically well-defined polyoxotitanate (POT, [TixOy(OR)z]) cage molecules can be determined. POTs may be preferred as soluble models of TiO2. Cages doped with a metal M (M-POT) presenting new properties can also be prepared.Two new cages doped with cerium were synthesized by a solvothermal reaction. The cages [Ti28O38(OEt)38CeCl](EtOH)1.4 and [Ti8O7(OEt)21Ce](EtOH) having different solubilities, they will be able to be separated and characterized by 1H NMR and X-ray diffraction. The Fe-doped POTs: [Ti4(OEt)15O(FeCl)] and [FeTi14(OEt)28O14(OH)2] were also synthesized. Then after hydrolysis with or without calcination, materials based on Ce or Fe and TiO2 can be obtained. Emulsions of its materials and with the cerium-doped PVDC polymer were then deposited on a PVC surface. UV absorption and water barrier performance gradually increases with increasing amount of deposited materials. The results are interesting for the use of these materials on the packaging surface of drug tablets, which will increase their expiry date. The Eu-POT cage doped with the Eu(III): Ti2O(OEt)8EuIIICl(EtOH)]2 was also synthesized, then after hydrolysis and calcination, the photoluminescence properties of the obtained material were studied.Finally, an AgITiIV(SC)2(HSC)(CH3CN) complex (SC2- = salicylate) was prepared. After hydrolysis and calcination, the anti-microbial properties of the materials were successfully tested against S. aureus or E. Colis
Karine, Bourgade. "Propriétés anti-virales des peptides β-amyloïdes associés à la maladie d'Alzheimer : implication dans le développement et la progression de la maladie." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8198.
El-Ghaish, Shady Nabil Rashed. "Usage des bactéries lactiques issues de produits laitiers fermentés ou de fromages locaux obtenus en Egypte dans la protéolyse des protéines du lait afin de diminuer leurs propriétés allergéniques et dans l'obtention de produits antimicrobiens." Nantes, 2011. http://archive.bu.univ-nantes.fr/pollux/show.action?id=b7546415-6795-4be6-8ea9-b7fbd47c219e.
The strains used in this study were identified by 16s rDNA amplification and sequencing as : Lactobacillus fermentum IFO3956, Lactobacillus rhamnosus LMS2, Lactobacillus plantarum JDM1, Enterococcus faecium DO623, Enterococcus faecium E1162, Enterococcus faecium C68, Enterococcus faecalis HH22 and Enterococcus faecalis T8. All these strains showed a strong proteolytic activity. The strains Lactobacillus fermentum IFO3956 and Lactobacillus plantarum JDM1 included PrtP protease, while the strain Lactobacillus rhamnosus LMS2 contain PrtR protease. No presence of genes encoding proteases PrtB and PrtH has been detected in all strains tested. Proteases produces by Lactobacillus fermentum IFO3956, Lactobacillus rhamnosus LMS2 and Lactobacillus plantarum JDM1 may be classified as P III type, since they proteolysed s1-, s2 and -caseins. Depending on the reduced recognition and binding by IgE of s1-, and -caseins hydrolyzed by Lb. Fermentum IFO3956, Lactobacillus rhamnosus LMS2 and Lactobacilus plantarum JDM1 these straine may be used for the production of milk products with reduced s1-and - caseins immuno-reactivity. The active strains (Enterococcus faecium TX1330 and Enterococcus faecium E980) isolated from Egyptian dairy products were proved capable of producing a variety of bacteriocins (ent A, ent B, ent P and ent L50A) with considerable activity against Listeria monocytogenes. Analysis of Enterococcus faecium TX1330 and Enterococcus faecium E980 by the methods of molecular biology has revealed the absence of the virulence factor genes (asal, cyl A and cyl B, ace, efaAfs, and espfm) as compared with a positive strain (Enterococcus faecalis MM4594). Based on the obtained results showing that the two studied strains producers of enterocins were devoid of virulence factors and mostly sensitive to antibiotics, Enterococcus faecium TX1330 and Enterococcus faecium E980 may be used as safe and useful starter cultures or co-cultures
Colak, Basak Yilin. "Utilisation du caséinate de sodium pour la fabrication de films actifs pour l’emballage alimentaire : étude des propriétés barrières aux gaz, de l’activité antimicrobienne et de la biodégradabilité." Thesis, Saint-Etienne, 2014. http://www.theses.fr/2014STET4018/document.
Because food market becomes international, consumers are changing their habits and they are more concerned about food security and environmental issues, there are driving forces for the development of edible/biodegradable antimicrobial packaging films. However, fabrication process (solution-casting) of these kinds of films isn’t always suitable for a continuous industrial big production. The present study demonstrates the suitability of sodium caseinate based edible antimicrobial films to be fabricated by some conventional plastic transformation processes: twinscrew extrusion and blown-film extrusion. Thanks to the optimizations of elaboration parameters such as extrusion temperature, shear and plasticizer ratio, the materials incorporated with one of the following active agents: lysozyme, nisin or natamycin, partially kept their antimicrobial activity. Physical-chemical film characterization of films emphasized that the type of transformation process doesn’t have any influence on tensile or gas barrier properties. These properties are mainly affected by plasticizer type and content. Thus, sodium caseinate based edible antimicrobial films can be produced successfully by thermo-mechanical processes without losing good mechanical and gas barrier properties
Kerangart, Stéphane. "Convergences évolutives et différenciations verticales chez les Escherichia coli producteurs de Shiga-toxines (STEC) pathogènes révélées par analyse de leurs propriétés métaboliques et de résistance aux antimicrobiens." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1091.
Shiga-toxin producing Escherichia coli (STEC) are major human pathogenic bacteria. These bacteria can cause hemorrhagic diarrheal diseases and Haemolytic and Uremic Syndromes. A risk assessment of more than 200 STEC serotypes has been performed using molecular markers of virulence and epidemiological datasets. However, virulence is not always associated with known or sufficiently described factors, questioning the reliability of such classifications. The hypothesis of this PhD work was that risk levels associated with STEC strains should be related not only to virulence specificities but also other metabolic properties such as a specialization for particular C-sources or resistances towards various antimicrobials. Few data were available on STEC physiology, with the exception of datasets regarding the metabolic properties exploited for the development of specific culture media. The aim of this work was to improve knowledge on STEC metabolic capacities and investigate relationships with their respective risk level. This work was divided into three parts: (i) a study of potassium tellurite (K2TeO3) resistance, an oxyanion highly toxic for cell membranes, (ii) a study of carbon metabolic profiles, and (iii) an exhaustive study of antibiotic and other antimicrobial resistances. A great variability in K2TeO3 resistance profiles was observed, as well as a phenomenon leading to the emergence of significant numbers of spontaneous mutants. The use of tellurite for STEC detection was found to lead to an underestimation of their prevalence in food products. Specific metabolic profiles including resistance to certain antimicrobial substances were found related to STEC classifications into risk levels. These data allowed us to observe specific vertical evolutions of these phenotypes per serogroup but some intergroup evolutionary convergences were also observed. These datasets led to the proposal of novel STEC detection and identification schemes. These schemes can be used by risk assessment managers for a better appreciation of STEC risk hazards among food and environmental samples
Outman, Ahlam. "Production de peptides anticancéreux à partir des hydrolysats d'hémoglobine humaine et bovine, avec des propriétés additionnelles antibactériennes et antioxydantes." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR082.
Hemoglobin, the predominant protein in cruor responsible for the red colour of mammalian blood, is known to be a rich source of bioactive peptides after hydrolysis by porcine pepsin. These peptides are mainly known for their antimicrobial properties. However, these peptides stand out for their ability to specifically target cancer cells while preserving rapidly proliferating healthy cells. The aim of this thesis is to develop a strategy for adding value to human and bovine haemoglobin by producing bioactive peptides and then exploring their potential in the fight against cancer, while assessing their anti-cancer, anti-bacterial and antioxidant properties.In this work, the potential of human hemoglobin to contain bioactive peptides was first studied in silico in comparison with bovine hemoglobin using bioinformatics tools. Blast results showed high identity, 88% and 85% respectively, indicating high similarity between α and β chains. The enzymatic hydrolysis conditions (23°C, E/S = 1/11, pH 3.5) were validated on human hemoglobin and enabled efficient production of the α137-141 peptide. Indeed, more than 60% of the total α137-141 peptide production was obtained in just 30 minutes of hydrolysis, reaching a production peak at 3 h. Furthermore, the mechanism of enzymatic hydrolysis of these two types of haemoglobin follows a similar pattern, according to a zipper mechanism. Enzymatic hydrolysis was also performed at high haemoglobin concentrations (1, 2, 8 and 10%, w/v), enabling large-scale production of α137-141.Next, the results showed strong antimicrobial activity of the peptide hydrolysates against six bacterial strains, independent of the initial substrate concentration level. The hydrolysates also showed strong antioxidant activity, measured by four different tests. In addition, the antimicrobial and antioxidant activities of the human and bovine haemoglobin hydrolysates showed little or no significant difference, with only the concentration level being the determining factor in their activity.The anticancer potential of bioactive peptides derived from the enzymatic hydrolysis of haemoglobin was studied. The results obtained using two distinct approaches highlighted their promising potential as anti-cancer agents. The investigation of key parameters such as the initial concentration of haemoglobin, the degree of hydrolysis and the structural characteristics of the antimicrobial peptides highlighted the influence of these factors on the antimitotic activity of the peptides. The α137-141 peptide stood out for its strong inhibition of rootlet growth, with exceptionally low IC50 values, 10 to 15 times higher than other fractions, attributed to its strong antimicrobial potential. In vitro analyses reinforced the hypothesis that inhibition of protein synthesis plays an essential role in the anti-cancer mechanism of these peptides.Finally, the results of the mass spectrometry study showed the presence of a number of bioactive peptides, the majority of which have characteristics similar to those reported in the literature. New bioactive peptides were also identified in human hemoglobin, such as the antibacterial peptides PTTKTYFPHF (α37-46), FPTTKTYFPH (α36-45), TSKYR (α137-141) and STVLTSKYR (α133-141), as well as the antioxidant TSKYR. (α137-141) including three other opioid peptides, an ACE inhibitor, an anticancer agent. This thesis offers a new innovative approach, combining antimicrobial, antioxidant and anticancer properties, paving the way for more effective and less harmful treatments for patients
Klipfel, Florian. "Formulation, mise en oeuvre et caractérisation de gants élastomères à caractère radioprotecteur et antimicrobien." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC201.
The aim of this study is to give new functionalities to elastomers that will be used as gloves. Some antimicrobials and radioprotective additives will be incorporated in different polymer matrixes. The elastomers have been realized by dip coating, the impact of the additives on the rheological properties of the solutions of elastomers was analysed. Some amines can interact with the elastomers in the solvent and accelerate the vulcanization. The thermal stability of the charged elastomers has then been investigated by thermogravimetric analysis and infrared measurments. Some metallic oxides interact with elastomers containing chlorine and change the dehydrochlorination process. The impact of the additives on the mechanical properties of vulcanized elastomers has been studied, the impact of some additives on the vulcanization and the existence of strong charge-polymer interactions have been demonstrated. Finally, a method to measure the radioprotective properties of filled elastomers has been developed to measure the attenuation of the composite against ionizing radiations