Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Mais filtros

Base de dados
Intervalo de ano de publicação
Microbiome ; 5(1): 125, 2017 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-28938903


BACKGROUND: Microbial communities in our built environments have great influence on human health and disease. A variety of built environments have been characterized using a metagenomics-based approach, including some healthcare settings. However, there has been no study to date that has used this approach in pre-hospital settings, such as ambulances, an important first point-of-contact between patients and hospitals. RESULTS: We sequenced 398 samples from 137 ambulances across the USA using shotgun sequencing. We analyzed these data to explore the microbial ecology of ambulances including characterizing microbial community composition, nosocomial pathogens, patterns of diversity, presence of functional pathways and antimicrobial resistance, and potential spatial and environmental factors that may contribute to community composition. We found that the top 10 most abundant species are either common built environment microbes, microbes associated with the human microbiome (e.g., skin), or are species associated with nosocomial infections. We also found widespread evidence of antimicrobial resistance markers (hits ~ 90% samples). We identified six factors that may influence the microbial ecology of ambulances including ambulance surfaces, geographical-related factors (including region, longitude, and latitude), and weather-related factors (including temperature and precipitation). CONCLUSIONS: While the vast majority of microbial species classified were beneficial, we also found widespread evidence of species associated with nosocomial infections and antimicrobial resistance markers. This study indicates that metagenomics may be useful to characterize the microbial ecology of pre-hospital ambulance settings and that more rigorous testing and cleaning of ambulances may be warranted.

Ambulâncias , Bactérias/isolamento & purificação , Metagenoma , Metagenômica , Consórcios Microbianos , Microbiota , Bactérias/classificação , Bactérias/genética , Bactérias/patogenicidade , Infecção Hospitalar/microbiologia , Genoma Bacteriano , Sequenciamento de Nucleotídeos em Larga Escala , Hospitais , Humanos , Consórcios Microbianos/genética , Microbiota/genética , Estados Unidos
Mol Ecol ; 25(15): 3622-31, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27072809


There is increasing evidence that evolution can occur rapidly in response to selection. Recent advances in sequencing suggest the possibility of documenting genetic changes as they occur in populations, thus uncovering the genetic basis of evolution, particularly if samples are available from both before and after selection. Here, we had a unique opportunity to directly assess genetic changes in natural populations following an evolutionary response to a fluctuation in climate. We analysed genome-wide differences between ancestors and descendants of natural populations of Brassica rapa plants from two locations that rapidly evolved changes in multiple phenotypic traits, including flowering time, following a multiyear late-season drought in California. These ancestor-descendant comparisons revealed evolutionary shifts in allele frequencies in many genes. Some genes showing evolutionary shifts have functions related to drought stress and flowering time, consistent with an adaptive response to selection. Loci differentiated between ancestors and descendants (FST outliers) were generally different from those showing signatures of selection based on site frequency spectrum analysis (Tajima's D), indicating that the loci that evolved in response to the recent drought and those under historical selection were generally distinct. Very few genes showed similar evolutionary responses between two geographically distinct populations, suggesting independent genetic trajectories of evolution yielding parallel phenotypic changes. The results show that selection can result in rapid genome-wide evolutionary shifts in allele frequencies in natural populations, and highlight the usefulness of combining resurrection experiments in natural populations with genomics for studying the genetic basis of adaptive evolution.

Brassica rapa/genética , Secas , Evolução Molecular , Pool Gênico , Seleção Genética , Adaptação Fisiológica/genética , California , Frequência do Gene , Genética Populacional , Genoma de Planta
Evolution ; 70(1): 241-8, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26648585


Recent studies have demonstrated adaptive evolutionary responses to climate change, but little is known about how these responses may influence ecological interactions with other organisms, including natural enemies. We used a resurrection experiment in the greenhouse to examine the effect of evolutionary responses to drought on the susceptibility of Brassica rapa plants to a fungal pathogen, Alternaria brassicae. In agreement with previous studies in this population, we found an evolutionary shift to earlier flowering postdrought, which was previously shown to be adaptive. Here, we report the novel finding that postdrought descendant plants were also more susceptible to disease, indicating a rapid evolutionary shift to increased susceptibility. This was accompanied by an evolutionary shift to increased specific leaf area (thinner leaves) following drought. We found that flowering time and disease susceptibility displayed plastic responses to experimental drought treatments, but that this plasticity did not match the direction of evolution, indicating that plastic and evolutionary responses to changes in climate can be opposed. The observed evolutionary shift to increased disease susceptibility accompanying adaptation to drought provides evidence that even if populations can rapidly adapt in response to climate change, evolution in other traits may have ecological effects that could make species more vulnerable.

Alternaria/fisiologia , Brassica rapa/microbiologia , Secas , Doenças das Plantas/microbiologia , Aclimatação , Evolução Biológica , Brassica rapa/fisiologia , Mudança Climática , Interações Hospedeiro-Patógeno
PLoS One ; 5(10): e13598, 2010 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-21049006


BACKGROUND: The effect of low nutrient availability on plant-consumer interactions during early succession is poorly understood. The low productivity and complexity of primary successional communities are expected to limit diversity and abundance of arthropods, but few studies have examined arthropod responses to enhanced nutrient supply in this context. We investigated the effects of nitrogen (N) and phosphorus (P) addition on plant productivity and arthropod abundance on 24-yr-old soils at Mount St. Helens volcano. METHODOLOGY/PRINCIPAL FINDINGS: We measured the relative abundance of eight arthropod orders and five families in plots that received N, P, or no nutrients for 3-5 years. We also measured plant % cover, leaf %N, and plant diversity. Vegetation responded rapidly to N addition but showed a lagged response to P that, combined with evidence of increased N fixation, suggested P-limitation to N availability. After 3 yrs of fertilization, orthopterans (primarily Anabrus simplex (Tettigoniidae) and Melanoplus spp (Acrididae)) showed a striking attraction to P addition plots, while no other taxa responded to fertilization. After 5 yrs of fertilization, orthopteran density in the same plots increased 80%-130% with P addition and 40% with N. Using structural equation modeling, we show that in year 3 orthopteran abundance was associated with a P-mediated increase in plant cover (or correlated increases in resource quality), whereas in year 5 orthopteran density was not related to cover, diversity or plant %N, but rather to unmeasured effects of P, such as its influence on other aspects of resource quality. CONCLUSIONS/SIGNIFICANCE: The marked surprising response to P by orthopterans, combined with a previous observation of P-limitation in lepidopteran herbivores at these sites, suggests that P-mediated effects of food quantity or quality are critical to insect herbivores in this N-P co-limited primary successional system. Our results also support a previous suggestion that the availability of N in these soils is P-limited.

Artrópodes/fisiologia , Desastres , Nitrogênio/metabolismo , Fosfatos/metabolismo , Animais , Artrópodes/metabolismo