Agrocampus Ouest

About: Agrocampus Ouest is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Soil water. The organization has 2160 authors who have published 3219 publications receiving 75606 citations. The organization is also known as: Institut supérieur des sciences agronomiques, agroalimentaires, horticoles et du paysage & Higher Institute for agricultural sciences, food industry, horticulture and landscape management.

Transcriptomic Response of Lactococcus lactis in Mixed Culture with Staphylococcus aureus

Abstract: The mechanisms of interaction between Lactococcus lactis and the food pathogen Staphylococcus aureus are of crucial importance, as one major role of lactic acid bacteria (LAB) in fermented foods is to inhibit undesirable and pathogenic flora. It was never questioned if the presence of a pathogen can actively modify the gene expression patterns of LAB in a shared environment. In this study, transcriptome and biochemical analyses were combined to assess the dynamic response of L. lactis in a mixed culture with S. aureus. The presence of S. aureus hardly affected the growth of L. lactis but dramatically modified its gene expression profile. The main effect was related to earlier carbon limitation and a concomitantly lower growth rate in the mixed culture due to the consumption of glucose by both species. More specific responses involved diverse cellular functions. Genes associated with amino acid metabolism, ion transport, oxygen response, menaquinone metabolism, and cell surface and phage expression were differentially expressed in the mixed culture. This study led to new insights into possible mechanisms of interaction between L. lactis and S. aureus. Moreover, new and unexpected effects of L. lactis on the virulence of S. aureus were discovered, as described elsewhere (S. Even, C. Charlier, S. Nouaille, N. L. Ben Zakour, M. Cretenet, F. J. Cousin, M. Gautier, M. Cocaign-Bousquet, P. Loubiere, and Y. Le Loir, Appl. Environ. Microbiol. 75:4459-4472, 2009).

To What Extent Do Whey and Casein Micelle Proteins Influence the Morphology and Properties of the Resulting Powder

Abstract: How the type of protein influences particle morphology remains a hot topic of debate. In this study we focused on the drying behavior of two major milk protein types; that is, whey protein and native micellar caseins. To improve understanding of the role of each protein in the particle-forming mechanisms, seven mixtures containing different whey proteins to caseins ratios were investigated. A monodisperse spray dryer (MDSD) was used to produce uniform particles by drying monodispersed droplets in a hot, dry air flow. Single particles were also obtained from the same material using single droplet drying in a pendant configuration. Powders were characterized according to their physical characteristics and their rehydration properties. It was demonstrated that particle morphology was mainly governed by the type of protein matrix, almost regardless of the drying kinetics, which differed considerably between MDSD and single droplet drying. Controlling product formulation thus represents a potential means by wh...

Environmental influences on life history strategies in partially anadromous brown trout (Salmo trutta, Salmonidae)

Abstract: This paper reviews the life history of brown trout and factors influencing decisions to migrate. Decisions that maximize fitness appear dependent on size at age. In partly anadromous populations, individuals that attain maturity at the parr stage typically become freshwater resident. For individual fish, the life history is not genetically fixed and can be modified by the previous growth history and energetic state in early life. This phenotypic plasticity may be influenced by epigenetic modifications of the genome. Thus, factors influencing survival and growth determine life-history decisions. These are intra- and interspecific competition, feeding and shelter opportunities in freshwater and salt water, temperature in alternative habitats and flow conditions in running water. Male trout exhibit alternative mating strategies and can spawn as a subordinate sneaker or a dominant competitor. Females do not exhibit alternative mating behaviour. The relationship between growth, size and reproductive success differs between sexes in that females exhibit a higher tendency to migrate than males. Southern populations are sensitive to global warming. In addition, fisheries, aquaculture with increased spreading of salmon lice, introduction of new species, weirs and river regulation, poor water quality and coastal developments all threaten trout populations. The paper summarizes life-history data from six populations across Europe and ends by presenting new research questions and directions for future research.