Search results for "adaptation"

Effect of expertise on boundary extension in approach sequences

2017

International audience; In a constantly changing environment, one of the conditions for adaptation is based on the visual system's ability to realize predictions. In this context, a question that arises is the evolution of the processes allowing anticipation with regard to the acquisition of knowledge relative to specific situations. We sought to study this question by focusing on boundary extension, the tendency to overestimate the scope of a previously perceived scene. We presented to novice, beginner, and expert car drivers road scenes in the form of approach sequences constituting very briefly displayed photographs (i.e., 250 milliseconds each), in order to determine the effect of exper…

Convergent adaptation of Saccharomyces uvarum to sulfite, an antimicrobial preservative widely used in human-driven fermentations

2021

Different species can find convergent solutions to adapt their genome to the same evolutionary constraints, although functional convergence promoted by chromosomal rearrangements in different species has not previously been found. In this work, we discovered that two domesticated yeast species, Saccharomyces cerevisiae, and Saccharomyces uvarum, acquired chromosomal rearrangements to convergently adapt to the presence of sulfite in fermentation environments. We found two new heterologous chromosomal translocations in fermentative strains of S. uvarum at the SSU1 locus, involved in sulfite resistance, an antimicrobial additive widely used in food production. These are convergent events that …

Context metadata to adapt Ambient Learning Environments

2008

Ambient learning and knowledge environments (ALKE) are a promising concept for new methods of learning and in particular adapted, personalized learning environments. However, currently very few approaches specify concepts for adaptation. We present a metadata approach to identify and (automatically) derive the context of learning environments as a basis for adaptation. The concept has been partially validated in a scenario of ldquoSpontaneous Group Learningrdquo in Higher Education.

2019

High dispersal rates are known to homogenize host's population genetic structure in panmictic species and to disrupt host local adaptation to the environment. Long-distance dispersal might also spread micro-organisms across large geographical areas. However, so far, to which extent selection mechanisms that shape host's population genetics are mirrored in the population structure of the enteric microbiome remains unclear. High dispersal rates and horizontal parental transfer may homogenize bacterial communities between breeding sites (homogeneous hypothesis). Alternatively, strong selection from the local environment may differentiate bacterial communities between breeding sites (heterogene…

ADAPTATION OF FLOURISHING AS POSITIVE PSYCHOLOGY CONCEPT IN LATVIA

2020

The aim of the study is to adapt linguistically and psychometrically the construct of flourishing and to compare four most popular measuring instruments by looking at their psychometric validity indicators and examining in more details the flourishing level of randomized sample in Latvia (N=312). As this construct was not adapted in Latvia jet, it is a new concept both – in terms of content and psychometry. Therefore, the tasks of research were more related to the study of the construct’s own content by comparing most popular flourishing measuring instruments, their internal consistency, analyzing the convergent validity of measuring instruments, and studying of the relationships between va…

Evolutionary dynamics of the E1-E2 viral populations during combination therapy in non-responder patients chronically infected with hepatitis C virus…

2012

Abstract Half of the patients chronically infected with hepatitis C virus (HCV) genotype 1 fail to respond to pegylated interferon alpha (PEG-IFN) and ribavirin (RBV) therapy. This study assesses the effects of treatment on the evolution of the E1–E2 viral region in non-responder patients infected with HCV-1b. Twenty-three HCV-1b chronically infected patients were studied retrospectively, including 19 non-responders to PEG-IFN/RBV therapy (11 null-responders and 8 relapsers) in the study group, and 4 untreated patients in the control group. Genetic and phylogenetic analyses of the E1–E2 viral populations were performed at baseline and at the time of treatment failure to assess changes in ge…

Molecular evolution in yeast of biotechnological interest

2003

The importance of yeast in the food and beverage industries was only realized about 1860, when the role of these organisms in food manufacture became evident. Since they grow on a wide range of substrates and can tolerate extreme physicochemical conditions, yeasts, especially the genera Saccharomyces and Kluyveromyces, have been applied to many industrial processes, Industrial strains of these genera are highly specialized organisms that have evolved to utilize a range of environments and ecological niches to their full potential. This adaptation is called "domestication". This review describes the phylogenetic relationships among Saccharomyces and Kluyveromyces species and the different me…

r- and K-selection in experimental populations of vesicular stomatitis virus.

2002

Here we explore the adaptation of vesicular stomatitis RNA virus to different population densities and the existence of a trade-off between r- and K-selection. Increasing population density represents a challenging special situation for viruses, since different selective pressures arise depending upon the number of available host cells per virus. Adaptation to low density represents a prototypical case of r-selection, where the optimal evolutionary solution should be a high replication rate. Adaptation to high density represents a case of K-selection. In this case, genotypes optimally exploiting the resources, instead of faster replicating ones, should be selected. Five independent populati…

Listeria monocytogenes, a down-to-earth pathogen

2013

International audience; Listeria monocytogenes is the causative agent of the food-borne life threatening disease listeriosis. This pathogenic bacterium received much attention in the endeavor of deciphering the cellular mechanisms that underlie the onset of infection and its ability to adapt to the food processing environment. Although information is available on the presence of L. monocytogenes in many environmental niches including soil, water, plants, foodstuff and animals, understanding the ecology of L. monocytogenes in outdoor environments has received less attention. Soil is an environmental niche of pivotal importance in the transmission of this bacterium to plants and animals. Soil…

Starvation can diversify the population structure and virulence strategies of an environmentally transmitting fish pathogen.

2013

Background Generalist bacterial pathogens, with the ability for environmental survival and growth, often face variable conditions during their outside-host period. Abiotic factors (such as nutrient deprivation) act as selection pressures for bacterial characteristics, but their effect on virulence is not entirely understood. “Sit and wait” hypothesis expects that long outside-host survival selects for increased virulence, but maintaining virulence in the absence of hosts is generally expected to be costly if active investments are needed. We analysed how long term starvation influences bacterial population structure and virulence of an environmentally transmitting fish pathogen Flavobacteri…