Despite efforts from a range of disciplines, our ability to predict and combat the evolution of antibiotic resistance in pathogenic bacteria is limited. This is because resistance evolution involves ...a complex interplay between the specific drug, bacterial genetics and both natural and treatment ecology. Incorporating details of the molecular mechanisms of drug resistance and ecology into evolutionary models has proved useful in predicting the dynamics of resistance evolution. However, putting these models to practical use will require extensive collaboration between mathematicians, molecular biologists, evolutionary ecologists and clinicians.
It is important to engage in regular physical activity in order to maintain a healthy lifestyle however a large portion of the population is insufficiently active. Understanding how different types ...of motivation contribute to exercise behavior is an important first step in identifying ways to increase exercise among individuals. The current study employs self-determination theory as a framework from which to examine how motivation contributes to various characteristics of exercise behavior.
Regular exercisers (N = 1079; n = 468 males; n = 612 females) completed inventories which assessed the frequency, intensity, and duration with which they exercise, as well as the Behavioral Regulation in Exercise Questionnaire including four additional items assessing integrated regulation.
Bivariate correlations revealed that all three behavioral indices (frequency, intensity, and duration of exercise) were more highly correlated with more autonomous than controlling regulations. Regression analyses revealed that integrated and identified regulations predicted exercise frequency for males and females. Integrated regulation was found to be the only predictor of exercise duration across both genders. Finally, introjected regulation predicted exercise intensity for females only.
These findings suggest that exercise regulations that vary in their degree of internalization can differentially predict characteristics of exercise behavior. Furthermore, in the motivational profile of a regular exerciser, integrated regulation appears to be an important determinant of exercise behavior. These results highlight the importance of assessing integrated regulation in exercise settings where the goal of understanding motivated behavior has important health implications.
Imagery is a widely spread technique in the sport sciences that entails the mental rehearsal of a given situation to improve an athlete’s learning, performance and motivation. Two modalities of ...imagery are reported to tap into distinct brain structures, but sharing common components: kinesthetic and visual imagery. This study aimed to investigate the neural basis of those types of imagery with Activation Likelihood Estimation algorithm to perform a meta − analysis. A systematic search was used to retrieve only experimental studies with athletes or sportspersons. Altogether, nine studies were selected and an ALE meta − analysis was performed. Results indicated significant activation of the premotor, somatosensory cortex, supplementary motor areas, inferior and superior parietal lobule, caudate, cingulate and cerebellum in both imagery tasks. It was concluded that visual and kinesthetic imagery share similar neural networks which suggests that combined interventions are beneficial to athletes whereas separate use of those two modalities of imagery may seem less efficient from a neuropsychological approach.
Abstract Exposure to a pathogen is predicted to lead to increased energy use as hosts attempt to activate a costly immune system and repair damaged tissue. To meet this demand, metabolic rates, which ...capture the rate at which a host can use, transform and expend energy, are expected to increase. Yet for many host–pathogen systems, metabolic rates after encountering a pathogen are just as likely to decrease as increase, suggesting that increased energy expenditure may not always be best for fighting infection. Diverging metabolic trajectories have been previously attributed to the different pathways that specific pathogen classes, such as bacteria or viruses, induce in a host. Here, we test how the magnitude and direction of metabolic change following pathogen exposure might also depend on whether a host has cleared infection or is instead fighting to reduce pathogen burden, as well as interactions between host and pathogen genotypes of a single host–pathogen system. Using a model system, Daphnia magna and its bacterial pathogen, we quantified changes in mass‐independent metabolic rates over a 30‐day period for multiple host and pathogen genotypes. We found that the metabolic trajectory of an exposed host diverged quickly during the infection process. For hosts that were exposed to a pathogen and resisted infection, their mass‐independent metabolic rates remained suppressed long after exposure, leading to a sustained reduction in total energy use compared to unexposed animals. The reverse was true for hosts in which the pathogen was able to establish an infection. Underlying these changes were differences in the energetic burden that each pathogen genotype imposed on its host, as well as changes in the way host genotype and the outcome of infection shaped underlying scaling relationships between host body mass and metabolic rates. Our results demonstrate how variation in an organism's metabolic rate and overall energy use can arise from within a single host–pathogen encounter and depend on the likelihood of pathogen clearance, as well as the within‐species genetic variability of both hosts and pathogens. Read the free Plain Language Summary for this article on the Journal blog.
To examine the relationship between Facebook (FB) use, relatedness and exercise motivation.
Two studies comprised a mixed-methods concurrent design. Study 1 was a cross-sectional quantitative ...assessment of the relationships between FB use, relatedness and exercise motivation.
Study 2 explored qualitative perceptions of how FB influences exercise motivation.
Study 1: 311 undergraduate students completed a survey assessing FB use, exercise motivation and relatedness. Mediation analysis was conducted to examine relationships. Study 2: 19 participants took part in focus groups exploring experiences of exercise-related FB use and its perceived role in motivation.
Study 1: FB use was related to external and introjected regulation. Relatedness mediated the relationships between FB use, introjection, and autonomous forms of motivation. Study 2: Qualitative data suggested FB can either promote (through connection, positive social comparison) or discourage exercise (through disconnection, negative social comparison, health-negating features).
FB use was related to external and introjected regulation. Positive relationships between FB and autonomous forms of motivation were mediated by relatedness, suggesting that interventions should focus on fostering feelings of connection with others. FB use that encourages relatedness with like-minded individuals has potential to promote autonomous motivation for exercise.
•FB can influence both controlled and autonomous forms of motivation.•Relatedness mediates the relationship between FB use and exercise motivation.•FB use that leads to feelings of disconnection can have negative effects on exercise.
The principles of systematic conservation planning are now widely used by governments and non-government organizations alike to develop biodiversity conservation plans for countries, states, regions, ...and ecoregions. Many of the species and ecosystems these plans were designed to conserve are now being affected by climate change, and there is a critical need to incorporate new and complementary approaches into these plans that will aid species and ecosystems in adjusting to potential climate change impacts. We propose five approaches to climate change adaptation that can be integrated into existing or new biodiversity conservation plans: (1) conserving the geophysical stage, (2) protecting climatic refugia, (3) enhancing regional connectivity, (4) sustaining ecosystem process and function, and (5) capitalizing on opportunities emerging in response to climate change. We discuss both key assumptions behind each approach and the trade-offs involved in using the approach for conservation planning. We also summarize additional data beyond those typically used in systematic conservation plans required to implement these approaches. A major strength of these approaches is that they are largely robust to the uncertainty in how climate impacts may manifest in any given region.
This study examined the effects of exercise imagery on implicit and explicit attitudes towards exercise and the moderating effect of exercise status. It was predicted that exercise imagery would ...activate a pattern of positive automatic associations with exercise that would be reflected in more positive implicit attitudes. Corresponding effects were expected for explicit affective attitudes, but imagery was not expected to influence explicit instrumental attitudes.
A post-test only comparison group design.
Participants (N = 160; 40 male and 40 female frequent exercisers, 40 male and 40 female less frequent exercisers) were randomly allocated, stratified by exercise status and gender, to undergo either guided imagery of a pleasant experience of exercising or a comparison imagery condition. Participants then completed an Implicit Association Test, measures of explicit affective and instrumental attitudes, and an imagery manipulation check.
There were significant main effects for experimental condition and exercise status on implicit attitudes, with more positive attitudes in the exercise imagery condition and for more frequent exercisers. There were significant main effects for exercise status on explicit affective and instrumental attitudes. Exercise status did not moderate the effects of imagery on implicit or explicit attitudes.
This is the first study to demonstrate that implicit attitudes to exercise can be modified, although only immediate effects were assessed. Future research should assess the generalisability of the findings in less active populations and examine the effects of repeated imagery on implicit attitudes to determine whether it could have more lasting effects and impact on actual exercise behaviour.
•We examined the effects of exercise imagery on implicit and explicit attitudes to exercise.•Guided imagery of a pleasant experience of exercising was compared to a control imagery condition.•Exercise imagery led to more positive implicit attitudes to exercise.•Exercise imagery had no effect on explicit attitudes.•This is the first study to demonstrate that implicit attitudes to exercise can be modified.
Epistatic interactions between resistance mutations in antibiotic-free environments potentially play a crucial role in the spread of resistance in pathogen populations by determining the fitness cost ...associated with resistance. We used an experimental evolution approach to test for epistatic interactions between 14 different pairs of rifampicin mutations in the pathogenic bacterium Pseudomonas aeruginosa in 42 different rifampicin-free environments. First, we show that epistasis between rifampicin-resistance mutations tends to be antagonistic: the fitness effect of having two mutations is generally smaller than that predicted from the effects of individual mutations on the wild-type. Second, we show that sign epistasis between resistance mutations is both common and strong; most notably, pairs of deleterious resistance mutations often partially or completely compensate for each others' costs, revealing a novel mechanism for compensatory adaptation. These results suggest that antagonistic epistasis between intragenic resistance mutations may be a key determinant of the cost of antibiotic resistance and compensatory adaptation in pathogen populations.
Metabolism is linked with the pace‐of‐life, co‐varying with survival, growth, and reproduction. Metabolic rates should therefore be under strong selection and, if heritable, become less variable over ...time. Yet intraspecific variation in metabolic rates is ubiquitous, even after accounting for body mass and temperature. Theory predicts variable selection maintains trait variation, but field estimates of how selection on metabolism varies are rare. We use a model marine invertebrate to estimate selection on metabolic rates in the wild under different competitive environments. Fitness landscapes varied among environments separated by a few centimeters: interspecific competition selected for higher metabolism, and a faster pace‐of‐life, relative to competition‐free environments. Populations experience a mosaic of competitive regimes; we find metabolism mediates a competition‐colonization trade‐off across these regimes. Although high metabolic phenotypes possess greater competitive ability, in the absence of competitors, low metabolic phenotypes are better colonizers. Spatial heterogeneity and the variable selection on metabolic rates that it generates is likely to maintain variation in metabolic rate, despite strong selection in any single environment.
A single regulatory protein can control the fate of many mRNAs with related functions. The Puf3 protein of Saccharomyces cerevisiae is exemplary, as it binds and regulates more than 100 mRNAs that ...encode proteins with mitochondrial function. Here we elucidate the structural basis of that specificity. To do so, we explore the crystal structures of Puf3p complexes with 2 cognate RNAs. The key determinant of Puf3p specificity is an unusual interaction between a distinctive pocket of the protein with an RNA base outside the "core" PUF-binding site. That interaction dramatically affects binding affinity in vitro and is required for regulation in vivo. The Puf3p structures, combined with those of Puf4p in the same organism, illuminate the structural basis of natural PUF-RNA networks. Yeast Puf3p binds its own RNAs because they possess a -2C and is excluded from those of Puf4p which contain an additional nucleotide in the core-binding site.
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