Early adaptation to oxygen is key to the industrially important traits of Lactococcus lactis ssp. cremoris during milk fermentation

Background: Lactococcus lactis is the most used species in the dairy industry. Its ability to adapt to technological stresses, such as oxidative stress encountered during stirring in the first stages of the cheese-making process, is a key factor to measure its technological performance. This study aimed to understand the response to oxidative stress of Lactococcus lactis subsp. cremoris MG1363 at the transcriptional and metabolic levels in relation to acidification kinetics and growth conditions, especially at an early stage of growth. For those purposes, conditions of hyper-oxygenation were initially fixed for the fermentation. Results: Kinetics of growth and acidification were not affected by the presence of oxygen, indicating a high resistance to oxygen of the L. lactis MG1363 strain. Its resistance was explained by an efficient consumption of oxygen within the first 4 hours of culture, leading to a drop of the redox potential. The efficient consumption of oxygen by the L. lactis MG1363 strain was supported by a coherent and early adaptation to oxygen after 1 hour of culture at both gene expression and metabolic levels. In oxygen metabolism, the over-expression of all the genes of the nrd (ribonucleotide reductases) operon or fhu (ferrichrome ABC transports) genes was particularly significant. In carbon metabolism, the presence of oxygen led to an early shift at the gene level in the pyruvate pathway towards the acetate/2,3-butanediol pathway confirmed by the kinetics of metabolite production. Finally, the MG1363 strain was no longer able to consume oxygen in the stationary growth phase, leading to a drastic loss of culturability as a consequence of cumulative stresses and the absence of gene adaptation at this stage. Conclusions: Combining metabolic and transcriptomic profiling, together with oxygen consumption kinetics, yielded new insights into the whole genome adaptation of L. lactis to initial oxidative stress. An early and transitional adaptation to oxidative stress was revealed for L. lactis subsp. cremoris MG1363 in the presence of initially high levels of oxygen. This enables the cells to maintain key traits that are of great importance for industry, such as rapid acidification and reduction of the redox potential of the growth media

La maturation du lait dans la fabrication de fromages à pâte pressée cuite: le rôle des lactocoques

* INRA URD BP 86510 21065 Dijon cedex (FRA) Diffusion du document : INRA URD BP 86510 21065 Dijon cedex (FRA) Diplôme : Dr. d'Universit

Production d'anticorps monoclonaux pour le dosage de l'alpha lactalbumine native par methode ELISA

* INRA Unite Regionale de Documentation B.V. 1540 21034 Dijon Cedex (FRA) Diffusion du document : INRA Unite Regionale de Documentation B.V. 1540 21034 Dijon Cedex (FRA) Diplôme : DE

What is the key to researchers’ job satisfaction? One response is professional identification mediated by work engagement

The job satisfaction of academics and researchers has been investigated recently, but the influence of different levels of socialidentification (organizational, workgroup and professional identification) has never been examined. The aim of the present studyis to examine the relationship between different levels of social identification, work engagement and job satisfaction. Our studyinvolved researchers from a French public institute who responded to an online survey (N = 383). The results show that differentlevels of social identification are positively correlated with researchers’ job satisfaction, and that workgroup explains the mostvariance, followed by professional and finally organizational identification. This study is also the first to show the mediating roleof the dedication dimension of work engagement on the relationships between professional identification and job satisfaction.The implications of the findings for future studies in research institutes and universities are discussed

Editorial: Exploring Bacterial Colonies in Solid Foods or Model Foods Using Non-Destructive Techniques

Editorial: Exploring Bacterial Colonies in Solid Foods or Model Foods Using Non-Destructive Technique

Creativity in research teams

This project aims to examine the effects of belonging to multidisciplinary groups (or unidisciplinary groups) on ideas generation by electronic brainwriting among researchers and staff of research in agri-food involved in a real innovation project in their laboratory

Creativity in Scientific Research: Multidisciplinarity Fosters Depth of Ideas Among Scientists in Electronic “Brainwriting” Groups

International audienceObjective The aim of this study was to examine the potential benefits of multidisciplinarity among agri-food researchers working in small groups to generate ideas to stimulate innovation in the context of a laboratory project. Background Research on the role of multidisciplinarity in scientific research teams remains limited, particularly regarding the generation of ideas to innovate in a real laboratory project, and on a task with a real challenge for innovation. Method Researchers and agri-food research staff were assigned to small groups of either multidisciplinary or unidisciplinary composition to produce ideas on a cross-cutting theme for an innovative laboratory project using an electronic “brainwriting” application. Results A greater depth in idea generation (number of ideas per category) was observed in the multidisciplinary condition than in the unidisciplinary condition. Conclusion The main benefits of this study were to experimentally examine the effects of multidisciplinarity in small scientific research groups on the production of ideas in a field study conducted on the premises of an agri-food laboratory. Application This study provides advice on how to promote innovative projects by stimulating ideation processes, which includes constructing small multidisciplinary groups and using an electronic “brainwriting” technique

Le rôle des lactocoques : une utilisation non systématique

National audienc

What is the key to researchers’ job satisfaction? One response is professional identification mediated by work engagement

International audienceThe job satisfaction of academics and researchers has been investigated recently, but the influence of different levels of social identification (organizational, workgroup and professional identification) has never been examined. The aim of the present study is to examine the relationship between different levels of social identification, work engagement and job satisfaction. Our study involved researchers from a French public institute who responded to an online survey (N = 383). The results show that different levels of social identification are positively correlated with researchers’ job satisfaction, and that workgroup explains the most variance, followed by professional and finally organizational identification. This study is also the first to show the mediating role of the dedication dimension of work engagement on the relationships between professional identification and job satisfaction. The implications of the findings for future studies in research institutes and universities are discussed

Heat resistance of wild Lactococcus lactis strains under a thermal gradient of cooked cheese, in milk and in mini-cheeses

International audienc