Sedentary lifestyle | EPFL Graph Search

Sedentary lifestyle is a lifestyle type, in which one is physically inactive and does little or no physical movement and or exercise. A person living a sedentary lifestyle is often sitting or lying down while engaged in an activity like socializing, watching TV, playing video games, reading or using a mobile phone or computer for much of the day. A sedentary lifestyle contributes to poor health quality, diseases as well as many preventable causes of death. Sitting time is a common measure of a sedentary lifestyle. A global review representing 47% of the global adult population found that the average person sits down for 4.7 to 6.5 hours a day with the average going up every year. The CDC found that 25.3% of all American adults are physically inactive. Screen time is a term for the amount of time a person spends looking at a screen such as a television, computer monitor, or mobile device. Excessive screen time is linked to negative health consequences. Definiti

Genetic, metabolic, and molecular insights into the diverse outcomes of diet-induced obesity in mouse

Alexis Maximilien Bachmann

Overweight and obesity are increasingly common public health issues worldwide, leading to a wide range of diseases from metabolic syndrome to steatohepatitis and cardiovascular diseases. While the increase in the prevalence of obesity is partly attributable to changes in lifestyle (i.e. increased sedentarity and changes in eating behaviour), the metabolic and clinical impacts of these obesogenic conditions varies between sexes and genetic backgrounds. The conception of personalised treatments of obesity and its complications require a thorough understanding of the diversity of responses to environmental stimuli such as high-fat diet intake. In this thesis, by analysing nine genetically diverse mouse strains, we show that much like humans, mice respond to high-fat diet in a genetic- and sex-dependent manner. Physiological and molecular responses to high-fat diet are associated with the expression of genes involved in immunity and mitochondrial function. Finally, we find that mitochondrial function and mitochondrial supercomplex assembly may explain part of the diversity of physiological responses. By exploring the complex interactions between genetics and metabolic phenotypes via gene expression and molecular traits, we shed light on the importance of genetic background and sex in determining metabolic outcomes. In addition to providing the community with an extensive resource for optimizing future experiments, this work serves as an exemplary design for more generalizable translational studies.

EPFL2021

Genetic manipulation of Vibrio cholerae by combining natural transformation with FLP recombination

Melanie Blokesch, Olga de Souza Silva

Even though Vibrio cholerae is a well-known human pathogen, it is also a normal member of aquatic habitats. Within this environment it often forms biofilms on the chitin-containing exoskeleton of crustaceans and their molts. Chitin not only serves as nutrient source but also induces a developmental program called natural competence. Naturally competent bacteria take up free DNA and integrate it into their genome by homologous recombination, thereby becoming naturally transformed. In this study, we made use of the knowledge on the environmental lifestyle of V. cholerae to genetically manipulate its genome. We achieved this by combining the methods of chitin-induced natural transformation and Flp recombination. Using this approach, we disrupted several genes by insertion of FRT-site-flanked antibiotic-resistance cassettes. The cassettes were subsequently excised by induction of the Flp recombinase, which acts on the FRT sites. This method represents a simplified and faster alternative to standard gene deletion techniques, which often depend on bacterial conjugation and the availability of suicide vectors.

Elsevier2010

Two nanomachines drive evolution in diverse Vibrio species

Noémie Matthey

Horizontal gene transfer (HGT) has a major impact on bacterial evolution, leading to acquisition or deletion of genes and gene clusters, including those encoding antibiotic resistances and virulence factors. HGT therefore contributes to pathogen emergence, which can have a major impact on human health. As a mode of HGT, natural competence for transformation allows bacteria to directly acquire DNA from the environment and to integrate parts of this genetic material within their genomes. The human pathogen Vibrio cholerae is naturally competent when it grows in association with the chitinous exoskeletons of zooplankton. Under this condition, the competence state is initiated by the regulatory protein TfoX, which co-induces a molecular killing device known as the type VI secretion system (T6SS). The co-regulation of the T6SS and competence results in the lysis of non-immune neighboring bacteria and the subsequent acquisition of their DNA, which fosters HGT. In V. cholerae, the T6SS is also activated by the TfoX homologue protein, named TfoY. In this study, we aimed at studying the regulatory pathways and the co-regulation of interbacterial predation and DNA uptake in order to provide new insights into the environmental lifestyle of V. cholerae and other vibrios. We first investigated the conserved function of TfoX- and TfoY in V. fischeri, V. alginolyticus, and V. parahaemolyticus using diverse methods such as qRT-PCR, interbacterial killing assays, and motility assessments. We demonstrated that TfoX-mediated T6SS and competence induction and TfoY-induced motility are conserved phenotypes in the tested Vibrio species, whereas the TfoY-mediated T6SS regulation varied. These variations might reflect diverse defense mechanisms, as these different species have adapted to cope with their environmental niches. Next, we tested the outcome of the TfoX-mediated co-regulation of the T6SS and competence in V. cholerae. Under conditions mimicking the bacteriumâs natural habitat, we showed for the first time the extent of DNA that was integrated on V. choleraeâs genome after T6SS-mediated interbacterial predation. Indeed, we demonstrated that T6SS-dependent bacterial predation not only increased the transformation rates but also fostered the exchange of multiple and huge fragments of DNA. We also showed the necessity of an exquisite co-regulation between the T6SS, the competence-related DNA uptake machinery, and the competence-repressed nuclease. Finally, we disclosed that prey-released DNA is not a private good of the attacking bacterium but also accessible to other surrounding cells that have likewise entered the competence state. Altogether, our findings shed light on the conservation of the TfoX- and TfoY-driven phenotypes in several Vibrio species. We also contributed to a better understanding of the interplay between neighbor predation and DNA uptake and the consequences that this interplay has on genome plasticity.

EPFL2019

Two nanomachines drive evolution in diverse Vibrio species

Noémie Matthey

EPFL2019