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51.
Demographic differences in diet breadth of Canada lynx during a fluctuation in prey availability 下载免费PDF全文
Christa M. Burstahler James D. Roth Robert J. Gau Dennis L. Murray 《Ecology and evolution》2016,6(17):6366-6375
Population dynamics of specialist carnivores are closely linked to prey availability, but the extent of variability in diet breadth of individual carnivores relative to natural variability in the abundance of their primary prey is not well understood. Canada lynx (Lynx canadensis) specialize on snowshoe hares (Lepus americanus) and exhibit cyclic fluctuations in abundance that lag 1–2 years behind those of snowshoe hares. Declining hare densities spur demographic changes in lynx, but it is unclear whether a corresponding increase in diet breadth occurs: (1) broadly across a lynx population; (2) only among individuals who are able to effectively switch to alternative prey; or (3) only among individuals who cannot capture sufficient primary prey. We measured stable isotope ratios of lynx muscle tissue spanning a cyclic increase and decline in hare density (1998–2001) in Fort Providence, NT, Canada. We found that lynx cohorts responded differently to hare population change, with yearling animals having broader diets at low hare densities, while adults and dependent juveniles maintained a constant diet through the initial decline in hare density. This result was consistent irrespective of lynx sex and indicates that yearling lynx likely are forced to adopt a broader diet when primary prey densities decline. Our results imply that select cohorts of specialist carnivores can exhibit high dietary plasticity in response to changes in primary prey abundance, prompting the need to determine whether increased diet breadth in young lynx is a successful strategy for surviving through periods of snowshoe hare scarcity. In this way, cohort‐specific niche expansion could strongly affect the dynamics of organisms exhibiting population cycles. 相似文献
52.
Wendy W. J. de Leng Christa G. Gadellaa-van Hooijdonk Fran?oise A. S. Barendregt-Smouter Marco J. Koudijs Ies Nijman John W. J. Hinrichs Edwin Cuppen Stef van Lieshout Robert D. Loberg Maja de Jonge Emile E. Voest Roel A. de Weger Neeltje Steeghs Marlies H. G. Langenberg Stefan Sleijfer Stefan M. Willems Martijn P. Lolkema 《PloS one》2016,11(2)
Background
Targeted Next Generation Sequencing (NGS) offers a way to implement testing of multiple genetic aberrations in diagnostic pathology practice, which is necessary for personalized cancer treatment. However, no standards regarding input material have been defined. This study therefore aimed to determine the effect of the type of input material (e.g. formalin fixed paraffin embedded (FFPE) versus fresh frozen (FF) tissue) on NGS derived results. Moreover, this study aimed to explore a standardized analysis pipeline to support consistent clinical decision-making.Method
We used the Ion Torrent PGM sequencing platform in combination with the Ion AmpliSeq Cancer Hotspot Panel v2 to sequence frequently mutated regions in 50 cancer related genes, and validated the NGS detected variants in 250 FFPE samples using standard diagnostic assays. Next, 386 tumour samples were sequenced to explore the effect of input material on variant detection variables. For variant calling, Ion Torrent analysis software was supplemented with additional variant annotation and filtering.Results
Both FFPE and FF tissue could be sequenced reliably with a sensitivity of 99.1%. Validation showed a 98.5% concordance between NGS and conventional sequencing techniques, where NGS provided both the advantage of low input DNA concentration and the detection of low-frequency variants. The reliability of mutation analysis could be further improved with manual inspection of sequence data.Conclusion
Targeted NGS can be reliably implemented in cancer diagnostics using both FFPE and FF tissue when using appropriate analysis settings, even with low input DNA. 相似文献53.
Gerald Sendlhofer David Benjamin Lumenta Karina Leitgeb Brigitte Kober Lydia Jantscher Monika Schanbacher Andrea Berghold Gudrun Pregartner Gernot Brunner Christa Tax Lars Peter Kamolz 《PloS one》2016,11(2)
Background
“The Surgical Safety Checklist (SSC) is important, but we don’t use it adequately” is a well-suited statement that reflects the SSC''s application in hospitals. Our aim was to follow up on our initial study on compliance (2014) by analysing differences between individual perception and compliance with the SSC.Methods
We conducted a follow-up online survey to assess healthcare professionals’ individual perception of, as well as satisfaction and compliance with the SSC three years following its thorough implementation.Results
171 (19.5%) of 875 operating team members completed the online survey. 99.4% confirmed using the SSC. Self-estimated subjective knowledge about the intention of the checklist was high, whereas objective knowledge was moderate, but improved as compared to 2014. According to an independent audit the SSC was used in 93.1% of all operations and among the SSCs used the completion rate was 57.2%. The use of the SSC was rated as rather easy [median (IQR): 7 (6–7)], familiar [7 (6–7)], generally important [7 (7–7)], and good for patients [7 (6–7)] as well as for employees [7 (7–7)]. Only comfort of use was rated lower [6 (5–7)].Conclusion
There is a gap between individual perception and actual application of the SSC. Despite healthcare professionals confirming the importance of the SSC, compliance was moderate. The introduction of SSCs in the health care sector remains a constant challenge and requires continuous re-evaluation as well as a sensible integration into existing workflows in hospitals. 相似文献54.
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56.
The high-osmolarity glycerol response pathway in the human fungal pathogen Candida glabrata strain ATCC 2001 lacks a signaling branch that operates in baker's yeast 总被引:1,自引:0,他引:1 下载免费PDF全文
Gregori C Schüller C Roetzer A Schwarzmüller T Ammerer G Kuchler K 《Eukaryotic cell》2007,6(9):1635-1645
The high-osmolarity glycerol (HOG) mitogen-activated protein (MAP) kinase pathway mediates adaptation to high-osmolarity stress in the yeast Saccharomyces cerevisiae. Here we investigate the function of HOG in the human opportunistic fungal pathogen Candida glabrata. C. glabrata sho1Delta (Cgsho1Delta) deletion strains from the sequenced ATCC 2001 strain display severe growth defects under hyperosmotic conditions, a phenotype not observed for yeast sho1Delta mutants. However, deletion of CgSHO1 in other genetic backgrounds fails to cause osmostress hypersensitivity, whereas cells lacking the downstream MAP kinase Pbs2 remain osmosensitive. Notably, ATCC 2001 Cgsho1Delta cells also display methylglyoxal hypersensitivity, implying the inactivity of the Sln1 branch in ATCC 2001. Genomic sequencing of CgSSK2 in different C. glabrata backgrounds demonstrates that ATCC 2001 harbors a truncated and mutated Cgssk2-1 allele, the only orthologue of yeast SSK2/SSK22 genes. Thus, the osmophenotype of ATCC 2001 is caused by a point mutation in Cgssk2-1, which debilitates the second HOG pathway branch. Functional complementation experiments unequivocally demonstrate that HOG signaling in yeast and C. glabrata share similar functions in osmostress adaptation. In contrast to yeast, however, Cgsho1Delta mutants display hypersensitivity to weak organic acids such as sorbate and benzoate. Hence, CgSho1 is also implicated in modulating weak acid tolerance, suggesting that HOG signaling in C. glabrata mediates the response to multiple stress conditions. 相似文献
57.
de Boer Gert-Jan Testerink Christa Pielage Gerlof Nijkamp H. John J. Stuitje Antoine R. 《Plant molecular biology》1999,39(6):1197-1207
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59.
Agonist-independent, high constitutive activity of the human melanocortin 1 receptor 总被引:3,自引:0,他引:3
Sánchez-Más J Hahmann C Gerritsen I García-Borrón JC Jiménez-Cervantes C 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》2004,17(4):386-395
The melanocortins (alpha-melanocyte-stimulating hormone and adrenocorticotropin) act on epidermal melanocytes to increase melanogenesis, the eumelanin/pheomelanin ratio and dendricity. These actions are mediated by the heptahelical melanocortin 1 receptor (MC1R), positively coupled to adenylyl cyclase. Gain-of-function mouse Mc1r alleles are associated with a dark, eumelanic coat. Conversely, loss-of-function variants, or overexpression of agouti, a natural melanocortin antagonist, yield yellow, pheomelanic furs. In humans, loss-of-function MC1R variants are associated with fair skin, poor tanning, propensity to freckle and increased skin cancer risk. Therefore, MC1R is a key regulator of mammalian pigmentation. Several observations such as induction of constitutive pigmentation in amelanotic mouse melanoma cells following expression of MC1R indicate that the receptor might display agonist-independent activity. We report a systematic and comparative study of MC1R and Mc1r constitutive activity. We show that expression of MC1R in heterologous systems leads to an agonist-independent increase in cyclic adenosine monophophate (cAMP). Basal signalling is a function of receptor expression and is two to fourfold higher for MC1R than for Mc1r. Moreover, it is observed in human melanoma cells over-expressing the MC1R. Constitutive signalling is abolished or reduced by point mutations of MC1R impairing the response to agonists, and is only doubled by the Lys94Glu mutation, mimicking the constitutively active mouse E(so-3J) allele. Stable or transient expression of wild-type MC1R, but not of loss-of-function mutants, potently stimulates forskolin activation of adenylyl cyclase, a common feature of constitutively active Gs-coupled receptors. Therefore, human MC1R displays a strong agonist-independent constitutive activity. 相似文献
60.
Rinder MR Spina RJ Peterson LR Koenig CJ Florence CR Ehsani AA 《American journal of physiology. Regulatory, integrative and comparative physiology》2004,287(2):R360-R368
To compare the effects of exercise training and hydrochlorothiazide on left ventricular (LV) geometry and mass, blood pressure (BP), and hyperinsulinemia in older hypertensive adults, we studied 28 patients randomized either to a group (age 66.4 +/- 1.3 yr; n = 16) that exercised or to a group (age 65.3 +/- 1.2 yr; n = 12) that received hydrochlorothiazide for 6 mo. Endurance exercise training induced a 15% increase in peak aerobic power. The reduction in systolic BP was twofold greater with thiazide than with exercise (26.6 +/- 12.2 vs. 11.5 +/- 10.9 mmHg). Exercise and thiazide reduced LV wall thickness, LV mass index (14% in each group), and the LV wall thickness-to-radius ratio (h/r) similarly (exercise: before 0.48 +/- 0.2, after 0.42 +/- 0.01; thiazide: before 0.47 +/- 0.04, after 0.40 +/- 0.04; P = 0.017). The reductions in systolic BP and h/r were correlated in the exercise group (r = 0.70, P = 0.005) but not in the thiazide group. Exercise training reduced glucose-stimulated hyperinsulinemia (before: 13.65 +/- 2.6 vs. 9.84 +/- 1.5 mU.ml(-1).min; P = 0.04) and insulin resistance. Thiazide did not affect plasma insulin levels. The results suggest that although exercise is less effective in reducing systolic BP than thiazide, it can induce regression of LV hypertrophy similar in magnitude to thiazide. Unlike hydrochlorothiazide, exercise training can improve insulin resistance and aerobic capacity in older hypertensive people. 相似文献