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排序方式: 共有5965条查询结果,搜索用时 15 毫秒
971.
Stephen R. Williams Qiong Yang Fang Chen Xuan Liu Keith L. Keene Paul Jacques Wei-Min Chen Galit Weinstein Fang-Chi Hsu Alexa Beiser Liewei Wang Ebony Bookman Kimberly F. Doheny Philip A. Wolf Michelle Zilka Jacob Selhub Sarah Nelson Stephanie M. Gogarten Bradford B. Worrall Sudha Seshadri Michèle M. Sale the Genomics Randomized Trials Network the Framingham Heart Study 《PLoS genetics》2014,10(3)
972.
Assaf Zaritsky Doron Kaplan Inbal Hecht Sari Natan Lior Wolf Nir S. Gov Eshel Ben-Jacob Ilan Tsarfaty 《PLoS computational biology》2014,10(7)
The ability of cells to coordinately migrate in groups is crucial to enable them to travel long distances during embryonic development, wound healing and tumorigenesis, but the fundamental mechanisms underlying intercellular coordination during collective cell migration remain elusive despite considerable research efforts. A novel analytical framework is introduced here to explicitly detect and quantify cell clusters that move coordinately in a monolayer. The analysis combines and associates vast amount of spatiotemporal data across multiple experiments into transparent quantitative measures to report the emergence of new modes of organized behavior during collective migration of tumor and epithelial cells in wound healing assays. First, we discovered the emergence of a wave of coordinated migration propagating backward from the wound front, which reflects formation of clusters of coordinately migrating cells that are generated further away from the wound edge and disintegrate close to the advancing front. This wave emerges in both normal and tumor cells, and is amplified by Met activation with hepatocyte growth factor/scatter factor. Second, Met activation was found to induce coinciding waves of cellular acceleration and stretching, which in turn trigger the emergence of a backward propagating wave of directional migration with about an hour phase lag. Assessments of the relations between the waves revealed that amplified coordinated migration is associated with the emergence of directional migration. Taken together, our data and simplified modeling-based assessments suggest that increased velocity leads to enhanced coordination: higher motility arises due to acceleration and stretching that seems to increase directionality by temporarily diminishing the velocity components orthogonal to the direction defined by the monolayer geometry. Spatial and temporal accumulation of directionality thus defines coordination. The findings offer new insight and suggest a basic cellular mechanism for long-term cell guidance and intercellular communication during collective cell migration. 相似文献
973.
Monica E. Calkins Tyler M. Moore Kathleen R. Merikangas Marcy Burstein Theodore D. Satterthwaite Warren B. Bilker Kosha Ruparel Rosetta Chiavacci Daniel H. Wolf Frank Mentch Haijun Qiu John J. Connolly Patrick A. Sleiman Hakon Hakonarson Ruben C. Gur Raquel E. Gur 《World psychiatry》2014,13(3):296-305
Little is known about the occurrence and predictors of the psychosis spectrum in large non‐clinical community samples of U.S. youths. We aimed to bridge this gap through assessment of psychosis spectrum symptoms in the Philadelphia Neurodevelopmental Cohort, a collaborative investigation of clinical and neurobehavioral phenotypes in a prospectively accrued cohort of youths, funded by the National Institute of Mental Health. Youths (age 11‐21; N=7,054) and collateral informants (caregiver/legal guardian) were recruited through the Children's Hospital of Philadelphia and administered structured screens of psychosis spectrum symptoms, other major psychopathology domains, and substance use. Youths were also administered a computerized neurocognitive battery assessing five neurobehavioral domains. Predictors of psychosis spectrum status in physically healthy participants (N=4,848) were examined using logistic regression. Among medically healthy youths, 3.7% reported threshold psychotic symptoms (delusions and/or hallucinations). An additional 12.3% reported significant sub‐psychotic positive symptoms, with odd/unusual thoughts and auditory perceptions, followed by reality confusion, being the most discriminating and widely endorsed attenuated symptoms. A minority of youths (2.3%) endorsed subclinical negative/disorganized symptoms in the absence of positive symptoms. Caregivers reported lower symptom levels than their children. Male gender, younger age, and non‐European American ethnicity were significant predictors of spectrum status. Youths with spectrum symptoms had reduced accuracy across neurocognitive domains, reduced global functioning, and increased odds of depression, anxiety, behavioral disorders, substance use and suicidal ideation. These findings have public health relevance for prevention and early intervention. 相似文献
974.
The response of species to climate change is generally studied using ex situ manipulation of microclimate or by modeling species range shifts under simulated climate scenarios. In contrast, a reciprocal transplant experiment was used to investigate the in situ adaptive response of the elevationally widespread epiphytic fern Asplenium antiquum to simulated climate change conditions. Fern spores were collected at three elevations and germinated in a greenhouse. The sporelings (juvenile ferns) were reciprocally transplanted to each collection site. Growth and mortality rates were monitored for 2 years. Wild sporelings were monitored at two sites to assess possible transplant effects. Habitat suitability, indicated by overall growth and survival patterns, declined as elevation increased. Only the highland population showed significant adaptation to the “home” habitat, achieving the highest survival rates. Microclimate data suggest that the presumed genetic adaptation at the highland site occurred mainly in response to drought stress in winter. Based on our previous study on species distribution models, which projected an expansion in the range of A. antiquum under future climate change scenarios, the populations at the upper margins of the species’ elevational range may play an important role during this expansion, given their better adaptation to the shifting marginal conditions. Our study suggests that intraspecific variation should be considered when determining the potential impact of climate change on biodiversity. 相似文献
975.
Alexander J. Wolf Eric C. Hellgren Eric M. Schauber Victor Bogosian III Richard T. Kazmaier Donald C. Ruthven III Raymond W. Moody 《Population Ecology》2014,56(4):619-631
Demographic studies of imperiled populations can aid managers in planning conservation actions. However, applicability of findings for a single population across a species’ range is sometimes questionable. We conducted long-term studies (8 and 9 years, respectively) of 2 populations of the lizard Phrynosoma cornutum separated by 1000 km within the historical distribution of the species. The sites were a 15-ha urban wildlife reserve on Tinker Air Force Base (TAFB) in central Oklahoma and a 6000-ha wildland site in southern Texas, the Chaparral Wildlife Management Area (CWMA). We predicted a trade-off between the effect of adult survival and fecundity on population growth rate (λ), leading to population-specific contributions of individual vital rates to λ and individualized strategies for conservation and management of this taxon. The CWMA population had lower adult survival and higher fecundity than TAFB. As predicted, there was a trade-off in the effects of adult survival and fecundity on λ between the two sites; fecundity affected λ more at CWMA than at TAFB. However, adult survival had the smallest effect on λ in both populations. We found that recruitment in P. cornutum most affected λ at both sites, with hatchling survival having the strongest influence on λ. Management strategies focusing on hatchling survival would strongly benefit both populations. As a consequence, within the constraint of the need to more accurately estimate hatchling survival, managers across the range of species such as P. cornutum could adopt similar management priorities with respect to stage classes, despite intra-population differences in population vital rates. 相似文献
976.
Cristina L. Vázquez Thomas R. Lerner Bahram Kasmapour Gang Pei Achim Gronow Maria V. Bianco Federico C. Blanco Christopher K. E. Bleck Robert Geffers Fabiana Bigi Wolf‐Rainer Abraham Maximiliano G. Gutierrez 《Cellular microbiology》2014,16(9):1425-1440
Some intracellular bacteria are known to cause long‐term infections that last decades without compromising the viability of the host. Although of critical importance, the adaptations that intracellular bacteria undergo during this long process of residence in a host cell environment remain obscure. Here, we report a novel experimental approach to study the adaptations of mycobacteria imposed by a long‐term intracellular lifestyle. Selected Mycobacterium bovis BCG through continuous culture in macrophages underwent an adaptation process leading to impaired phenolic glycolipids (PGL) synthesis, improved usage of glucose as a carbon source and accumulation of neutral lipids. These changes correlated with increased survival of mycobacteria in macrophages and mice during re‐infection and also with the specific expression of stress‐ and survival‐related genes. Our findings identify bacterial traits implicated in the establishment of long‐term cellular infections and represent a tool for understanding the physiological states and the environment that bacteria face living in fluctuating intracellular environments. 相似文献
977.
Silvia G?rtner Angela Gunesch Tatiana Knyazeva Petra Wolf Bernhard H?gel Wolfgang Eiermann Axel Ullrich Pjotr Knyazev Beyhan Ataseven 《PloS one》2014,9(1)
Protein Tyrosin Kinase 7 (PTK7) is upregulated in several human cancers; however, its clinical implication in breast cancer (BC) and lymph node (LN) is still unclear. In order to investigate the function of PTK7 in mediating BC cell motility and invasivity, PTK7 expression in BC cell lines was determined. PTK7 signaling in highly invasive breast cancer cells was inhibited by a dominant-negative PTK7 mutant, an antibody against the extracellular domain of PTK7, and siRNA knockdown of PTK7. This resulted in decreased motility and invasivity of BC cells. We further examined PTK7 expression in BC and LN tissue of 128 BC patients by RT-PCR and its correlation with BC related genes like HER2, HER3, PAI1, MMP1, K19, and CD44. Expression profiling in BC cell lines and primary tumors showed association of PTK7 with ER/PR/HER2-negative (TNBC-triple negative BC) cancer. Oncomine data analysis confirmed this observation and classified PTK7 in a cluster with genes associated with agressive behavior of primary BC. Furthermore PTK7 expression was significantly different with respect to tumor size (ANOVA, p = 0.033) in BC and nodal involvement (ANOVA, p = 0.007) in LN. PTK7 expression in metastatic LN was related to shorter DFS (Cox Regression, p = 0.041). Our observations confirmed the transforming potential of PTK7, as well as its involvement in motility and invasivity of BC cells. PTK7 is highly expressed in TNBC cell lines. It represents a novel prognostic marker for BC patients and has potential therapeutic significance. 相似文献
978.
979.
Emma Komulainen Katarina Meskanen Jari Lipsanen Jari Marko Lahti Pekka Jylh? Tarja Melartin Marieke Wichers Erkki Isomets? Jesper Ekelund 《PloS one》2014,9(10)
Personality features are associated with individual differences in daily emotional life, such as negative and positive affectivity, affect variability and affect reactivity. The existing literature is somewhat mixed and inconclusive about the nature of these associations. The aim of this study was to shed light on what personality features represent in daily life by investigating the effect of the Five Factor traits on different daily emotional processes using an ecologically valid method. The Experience Sampling Method was used to collect repeated reports of daily affect and experiences from 104 healthy university students during one week of their normal lives. Personality traits of the Five Factor model were assessed using NEO Five Factor Inventory. Hierarchical linear modeling was used to analyze the effect of the personality traits on daily emotional processes. Neuroticism predicted higher negative and lower positive affect, higher affect variability, more negative subjective evaluations of daily incidents, and higher reactivity to stressors. Conscientiousness, by contrast, predicted lower average level, variability, and reactivity of negative affect. Agreeableness was associated with higher positive and lower negative affect, lower variability of sadness, and more positive subjective evaluations of daily incidents. Extraversion predicted higher positive affect and more positive subjective evaluations of daily activities. Openness had no effect on average level of affect, but predicted higher reactivity to daily stressors. The results show that the personality features independently predict different aspects of daily emotional processes. Neuroticism was associated with all of the processes. Identifying these processes can help us to better understand individual differences in daily emotional life. 相似文献
980.
Ido Wolf Shiri Shahmoon Michal Ben Ami Yael Levy-Shraga Kineret Mazor-Aronovitch Orit Pinhas-Hamiel Yonatan Yeshayahu Rina Hemi Hannah Kanety Tami Rubinek Dalit Modan-Moses 《PloS one》2014,9(9)