Search results for "LOCUS"
showing 10 items of 632 documents
A genomic epidemiology investigation of yaws re-emergence and bacterial drug resistance selection
2020
Abstract Background In a longitudinal study assessing the WHO strategy for yaws eradication using mass azithromycin treatment, we observed resurgence of yaws cases with dominance of a single JG8 sequence type and emergence of azithromycin-resistant Treponema pallidum. Here, we analyse genomic changes in the bacterial population using samples collected during the study. Methods We performed whole bacterial genome sequencing directly on DNA extracted from 37 lesion swabs collected from patients on Lihir Island, Papua New Guinea, between 2013 and 2016. We produced phylogenies and correlated these with temporo-spatial information to investigate the source of new cases and the emergence of five …
Bifurcations in the elementary Desboves family
2017
International audience; We give an example of a family of endomorphisms of $\mathbb{P}^2(\mathbb{C})$ whose Julia set depends continuously on the parameter and whose bifurcation locus has non-empty interior.
Geodesic flow of the averaged controlled Kepler equation
2008
A normal form of the Riemannian metric arising when averaging the coplanar controlled Kepler equation is given. This metric is parameterized by two scalar invariants which encode its main properties. The restriction of the metric to $\SS^2$ is shown to be conformal to the flat metric on an oblate ellipsoid of revolution, and the associated conjugate locus is observed to be a deformation of the standard astroid. Though not complete because of a singularity in the space of ellipses, the metric has convexity properties that are expressed in terms of the aforementioned invariants, and related to surjectivity of the exponential mapping. Optimality properties of geodesics of the averaged controll…
Conjugate and cut loci of a two-sphere of revolution with application to optimal control
2008
Abstract The objective of this article is to present a sharp result to determine when the cut locus for a class of metrics on a two-sphere of revolution is reduced to a single branch. This work is motivated by optimal control problems in space and quantum dynamics and gives global optimal results in orbital transfer and for Lindblad equations in quantum control.
Natural soil reservoirs for human pathogenic and fecal indicator bacteria
2015
Prod ? EA UB INRA BIOME; International audience; résumé du livre : Environmental microbiology, the study of the roles that microbes play in all planetary environments, is one of the most important areas of scientific research. The The Manual of Environmental Microbiology, Fourth Edition, provides comprehensive coverage of this critical and growing field. Thoroughly updated and revised, the Manuall is the definitive reference for information on microbes in air, water, and soil and their impact on human health and welfare. Written in accessible, clear prose, the manual covers four broad areas: general methodologies, environmental public health microbiology, microbial ecology, and biodegradati…
Relationships between Staphylococcus aureus genetic background, virulence factors, agr groups (alleles), and human disease
2002
ABSTRACT The expression of most Staphylococcus aureus virulence factors is controlled by the agr locus, which encodes a two-component signaling pathway whose activating ligand is an agr -encoded autoinducing peptide (AIP). A polymorphism in the amino acid sequence of the AIP and of its corresponding receptor divides S. aureus strains into four major groups. Within a given group, each strain produces a peptide that can activate the agr response in the other member strains, whereas the AIPs belonging to different groups are usually mutually inhibitory. We investigated a possible relationship between agr groups and human S. aureus disease by studying 198 S. aureus strains isolated from 14 asym…
Differential expression of the agr locus of Listeria monocytogenes EGD-e
2007
International audience
Enteropathogenic Escherichia coli O103 from rabbit elicits actin stress fibers and focal adhesions in HeLa epithelial cells, cytopathic effects that …
1997
Escherichia coli O103, a major agent of weaned-rabbit diarrhea in Western Europe, was previously shown to produce diarrhea and attaching-and-effacing intestinal lesions in experimentally infected rabbits and to possess a homolog of the eaeA gene of enteropathogenic E. coli (EPEC). In the present study, we have shown that although negative in the fluorescent-actin staining test on HeLa cells, prototype rabbit E. coli O103 strain B10 was able to induce an original cytopathic effect (CPE) in the same interaction model. This CPE was characterized by a generalized reorganization of the actin cytoskeleton and the formation of focal adhesions on the entire surface of the target cells. These effect…
Fructose 2,6-bisphosphate as a signal for changing from sugar to lipid oxidation during flight in locusts
1986
AbstractFlight in locusts is initially powered mainly by carbohydrate but if flight is to be sustained, as in migration, the animals have to utilize fat as the predominant fuel. The molecular basis of this metabolic switch has not been identified. Fructose 2,6-bisphosphate is a potent activator of 6-phosphofructokinase (EC 2.7.1.11) purified from locust flight muscle. After the first few minutes of flight in the locust the concentration of fructose 2,6-bisphosphate in the flight muscle falls dramatically, which should lead to a decrease in the activity of 6-phosphofructokinase as part of the mechanism to conserve carbohydrate during prolonged flight.
A contribution to the study of staling of white bread: effect of water and hydrocolloid
1996
Abstract Staling of white bread at ambient temperature was studied using differential scanning calorimetry and dynamic mechanical thermal analysis. During storage, sample hydration varied slightly, from 0 to 0.4% per day, depending on packaging conditions. An increase in rigidity was observed, which was attributed both to starch retrogradation and to changes in the organization of the amorphous part of crumb. The glass transition temperature of crumb was not significantly modified by these structural changes. Hydrocolloids did not affect the overall shape of the viscoelastic behavior of crumb in the temperature range from −40°C to 80°C, and had a limited influence on the kinetics of starch …