Search results for "Persistence"
showing 10 items of 243 documents
Absolute Humidity Influences the Seasonal Persistence and Infectivity of Human Norovirus
2014
ABSTRACT Norovirus (NoV) is one of the main causative agents of acute gastroenteritis worldwide. In temperate climates, outbreaks peak during the winter season. The mechanism by which climatic factors influence the occurrence of NoV outbreaks is unknown. We hypothesized that humidity is linked to NoV seasonality. Human NoV is not cultivatable, so we used cultivatable murine norovirus (MNV) as a surrogate to study its persistence when exposed to various levels of relative humidity (RH) from low (10% RH) to saturated (100% RH) conditions at 9 and 25°C. In addition, we conducted similar experiments with virus-like particles (VLPs) from the predominant GII-4 norovirus and studied changes in bin…
Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia.
2016
Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especial…
Persistent establishment of a tropical disease in Europe: the preadaptation of schistosomes to overwinter
2019
International audience; Background: Global changes promote the spread of infectious diseases worldwide. In this context, tropical uro-genital schistosomiasis is now permanently established in Corsica since its first emergence in 2013. The local persistence of the tropical pathogens (schistosomes) responsible for urogenital schistosomiasis at such latitudes might be explained by (i) the presence of its intermediate host, the snail Bulinus truncatus, (ii) the recurrent local reseeding of schistosomes by their vertebrate hosts (either human or animal) every summer, and/or (iii) the maintenance and survival of schistosomes within their snail hosts over winter.Methods: In this study we conducted…
Persistance and adaptation of Listeria monocytogenes in the soil : role of the communication system Agr
2014
Listeria monocytogenes is a ubiquitous bacterium responsible for listeriosis, a food-borne disease. This pathogen has been isolated from various environments of which the telluric environment. The presence of L. monocytogenes in soil can increase health hazards due to the risk of transfer to vegetables, animals and animal products and water. Considering the role of soil in the circulation of pathogens from farm environment to plant and animal products and eventually to foodstuff, it is critical to identify intrinsic and extrinsic factors that drive the fate of L. monocytogenes in soil. Genome-wide and transcriptomic analyses found that an important part of the genome of L. monocytogenes (7.…
Étude de la biologie d'une messicole en régression: le bleuet (Centaurea cyanus L.)
2011
Agroecosystems are currently experiencing high biodiversity loss, in particular among the plant species specifically adapted to this habitat. This decline results from cropping systems that have been intensified in Western Europe since the 1950s. The cornflower (Centaurea cyanus L.), considered as emblem of the flora associated with traditional cereals, appears as a species that may be at risk and should be monitored. Indeed, cornflower can serve as a host to predators of crop pests and is strongly attractive for the pollinators. This study examines the biological factors that could potentially cause the decline of this species: spatial distribution, potential for growth, population's genet…
Differential memory persistence of odor mixture and components in newborn rabbits: competition between the whole and its parts
2014
Interacting with the mother during the daily nursing, newborn rabbits experience her body odour cues. In particular, the mammary pheromone (MP) contained in rabbit milk triggers the typical behaviour which helps to localize and seize the nipples. It also promotes the very rapid appetitive learning of simple or complex stimuli (odorants or mixtures) through associative conditioning. We previously showed that 24h after MP-induced conditioning to odorants A (ethyl isobutyrate) or B (ethyl maltol), newborn rabbits perceive the AB mixture in a weak configural way, i.e. they perceive the odour of the AB configuration in addition to the odours of the elements. Moreover, after conditioning to the m…
Parental Involvement in Math Homework: Links to Children’s Performance and Motivation
2017
The present study examined the longitudinal associations between children’s perceptions of parental involvement in math homework (control and support) and their math performance and motivation (taskpersistent homework behavior and math self-concept). Children (n = 512) reported their perceptions concerning parental involvement in sixthgrade math homework. In grades 3 and 6, children completed math tests, evaluated own math self-concept, and their mothers (n = 420) evaluated task persistence during homework. The results showed that low selfconcept in math predicted increased parental control, which in turn related to low math performance, task persistence, and math selfconcept. Second, perce…
Antibodies Responses to SARS-CoV-2 in a Large Cohort of Vaccinated Subjects and Seropositive Patients
2021
Background: COVID-19 is a current global threat and characterisation of antibody response to SARS-CoV-2 is vitally important to update vaccine development and strategies. Methods: In this study we assessed SARS-CoV-2 antibody concentrations in SARS-CoV-2 positive patients (N=272) and subjects vaccinated with BNT162b2 m-RNA Covid-19 vaccine (N=1,256). For each participant socio-demographic data, COVID-19 vaccination records, serological analyses and SARS-CoV-2 infection status have been collected. IgM and IgG antibodies against S1/S2 antigens of SARS-CoV-2 were detected. Findings: Almost all vaccinated subjects (99·8%) showed a seropositivity to anti-SARS-COV-2 IgG and more than 80% vaccinat…
SARS-CoV-2 RNA and antibody detection in human milk from a prospective multicenter study in Spain
2021
Background During the COVID-19 pandemic in 2020, breastfeeding in women positive for SARS-CoV-2 was compromised due to contradictory data regarding potential viral transmission. However, growing evidence confirms the relevant role of breast milk in providing passive immunity by generating and transmitting specific antibodies against the virus. Thus, our study aimed to develop and validate a specific protocol to detect SARS-CoV-2 in breast milk matrix as well as to determine the impact of maternal SARS-CoV-2 infection on presence, concentration, and persistence of specific SARS-CoV-2 antibodies. Study design/Methods A prospective multicenter longitudinal study in Spain was carried out from A…