Search results for "Bactérie"
showing 10 items of 69 documents
Study of the biochemical composition and physico-chemistry of a protein-based food model of Parkia biglobosa
2022
In West Africa, the seed of the cowpea (Parkia biglobosa) is used in traditional pharmacopoeia and especially in human food as a condiment. This legume is very rich in proteins and lipids and remains a poorly exploited source of protein. Our thesis focuses on the valorization of Néré seeds for the development of new protein-rich products of plant origin as an alternative to the use of soybean as a basic ingredient. The objectives were : (i)biochemical and physicochemical characterization of protein isolates from Néré seed flour according to the extraction process, (ii) selection of proteolytic lactic acid bacteria capable of fermenting Néré juice, reducing anti-nutritional factors in order …
Lactic acid bacteria strains for bioprotection application with cells entrapment in biopolymeric matrices
2013
Among the various methods to control foodborne pathogenic and/or food spoilage microorganisms in food chain, bioprotective lactic acid bacteria (LAB) appear to be promising tools for food biopreservation. This collaborative study, between PAPC (Agrosup Dijon, University of Burgundy) and BioDyMIA (University Lyon1-Lyon Isara) laboratories, concerned the development of sodium alginate/sodium caseinate polymeric matrices intended to entrap LAB cells selected for their anti-Listeria spp. activity. First, 4 LAB strains from 19 LAB strains were selected for their anti-Listeria spp. activity: this screening was performed by the method of agar diffusion against three Listeria spp strains. Then, ant…
Revelation of aroma potential of grape pomace and spent coffee ground by the use of microbial glycosidases.
2021
The food industry is evolving and tends to reduce its environmental impact, to control its waste and to valorise all of its production. Grapes and coffee are among the main agricultural products in the world and not all of the byproducts resulting from their processing are still valued today. New ways of valorisation are seeked in order to limit production losses. Yet, these byproducts are rich in glycosides, the amount of which may be from two to five times greater than that of the free volatile compounds. Grape pomace and spent coffee ground could be used to naturally produce volatile compounds from their glycosides. These volatile compounds could be useful in the production of cosmetics,…
Development of multidimensional spectroscopic and microscopic techniques to facilitate the monitoring of native fluorescence of biomolecules.
2022
There is a need for the development of rapid and reliable characterization tools for biological media. The objective of this thesis is to develop a method based on the acquisition of excitation-emission matrices of fluorescence (EEMF) coupled with the use of fluorescence lifetime measurement in spectroscopy and microscopy (FLIM). These techniques have great potential due to their speed, low sample volume required for analysis, non-destructive sample analysis, and low cost. This project focused on two biological media of great interest to the food industry: wine and bacterial spores. On one hand, we have a beverage representing a large world market, and on the other hand, a food contaminant …
Effects of high pressure processing and biopreservation on the inactivation and the germination of spores of Bacillus and Clostridium
2018
Bacterial endospores are one of the most resistant life form on earth. Their capacity to survive to decontamination processes and their potential pathogenicity represent a real problem for the food industry. Currently, the only way to prevent their development in foods is the application of thermal treatments or the use of preservatives. However, these two methods have negative impacts on the nutritional properties of foods and on the consumers’ health. High hydrostatic pressure (HP) is a non-thermal process widely used for commercial pasteurization of foods. However, this process has a very low effect on spores and has therefore to be combined with other decontamination processes to enhanc…
Impact of polyphenols and feeding rhythms on the immunomodulation properties of the probiotic bacteria in the gastro-intestinal tract
2021
The human intestinal microbiota is composed of several types of microorganisms, including bacteria, archaea, fungi, unicellular eukaryotes and viruses. Among them, bacteria are the most diverse and abundant with a gene catalog 150 times larger than the genes present in the human genome, which represents a tremendous metabolic potential. These bacteria actively participate in the maintenance of intestinal homeostasis. Dysbiosis of the gut microbiota could be observed at course of many human pathologies, particularly inflammatory diseases intestinal chronic diseases (IBD), such as Crohn's disease (CD) or Ulcerative colitis (UC). These dysbiosis could contribute to the onset and progression of…
Finding the missing link between diversity and activity using denitrifying bacteria as a model functional community
2005
The recent development and application of numerous methods mainly based on 16S rDNA analyses have brought insights into the questions of which and how many bacterial populations can be found in a given ecosystem. A new and challenging question for microbial ecologists has emerged from the exploration of this diversity: what is its significance for ecosystem functioning? We propose the denitrifying bacteria as a model microbial community for understanding the relationship between community structure and activity, and have summarized the recent progress in studies of this functional community.
Denitrification in pathogenic bacteria : for better or worst ?
2005
A large variety of physiological and taxonomic groups have the ability to use nitrogen oxides as alternative electron acceptors. Brucella spp. is an alpha-proteobacteriaceae that induces a persistent disease in some mammals. Recent work has revealed that a denitrifying gene cluster is important in the interaction of Brucella neotomoae with its host.
Occurrence of CTX-M Producing Escherichia coli in Soils, Cattle, and Farm Environment in France (Burgundy Region).
2012
Article en open access; International audience; CTX-M [a major type of extended-spectrum beta-lactamase (ESBU] producing Escherichia coli are increasingly involved in human infections worldwide. The aim of this study was to investigate potential reservoirs for such strains: soils, cattle, and farm environment. The prevalence of bla(CTX-M) genes was determined directly from soil DNA extracts obtained from 120 sites in Burgundy (France) using real-time PCR. bla(CTX-M) targets were found in 20% of the DNA extracts tested. Samples of cattle feces (n = 271) were collected from 182 farms in Burgundy. Thirteen ESBL-producing isolates were obtained from 12 farms and further characterized for the pr…
Implication of an odorant-binding protein in precopulatory behaviour and interaction with the bacterial microbiota
2023
Chemoreception allows animals to detect nutritive food and avoid toxic compounds. Volatile and non-volatile chemical compounds, which are detected by olfactory and gustatory sensory organs, can trigger feeding and reproductive behaviours in animals such as Drosophila melanogaster. Inside chemosensory organs, perireceptor proteins like odorant-binding proteins (OBPs) serve to transport odorant and tastant molecule to dedicated receptors. OBPs are not only involved in chemoreception but also in several other functions. A recent study revealed an interaction between insect microbiota and OBP expression while another one showed that microbes can promote nutrient harvesting on food. In our proje…