96 research outputs found
Fourteen Polymorphic Microsatellite Markers for the Widespread Labrador Tea (Rhododendron groenlandicum)
PREMISE: Microsatellite markers were developed for Labrador tea (Rhododendron groenlandicum, Ericaceae) to facilitate downstream genetic investigation of this species and the extremely closely related, circumboreal Rhododendron subsect. Ledum. METHODS AND RESULTS: Forty-eight primer pairs were designed using Illumina data and screened for excellent amplification. Sixteen successful pairs were developed as microsatellite markers using fluorescently labeled amplification to generate chromatogram data. These data were evaluated for intrapopulation and interpopulation variability in three populations from Alaska and Maine, USA, and the Northwest Territories, Canada. Fourteen polymorphic markers genotyped reliably, each with one to eight alleles. Cluster analysis indicates that across the range, populations can be easily discriminated. Cross-amplification in other Rhododendron subsect. Ledum species shows broad application of the developed markers within this small, well-supported clade. CONCLUSIONS: These microsatellite markers exhibit significant variability and will be useful in population genetics within R. groenlandicum and for investigation of species boundaries across Rhododendron subsect. Ledu
Microsatellite markers for the biogeographically enigmatic sandmyrtle (Kalmia buxifolia, Phyllodoceae: Ericaceae)
Premise:
Microsatellite markers were developed for sandmyrtle, Kalmia buxifolia (Ericaceae), to facilitate phylogeographic studies in this taxon and possibly many of its close relatives.
Methods and Results:
Fortyâeight primer pairs designed from pairedâend Illumina MiSeq data were screened for robust amplification. Sixteen pairs were amplified again, but with fluorescently labeled primers to facilitate genotyping. Resulting chromatograms were evaluated for variability using three populations from Tennessee, North Carolina, and New Jersey, USA. Eleven primer pairs were reliable and polymorphic (mean 3.92 alleles), one was reliable but monomorphic, and four were not reliable. The markers exhibited lower heterozygosity (mean 0.246) than expected (mean 0.464). Crossâamplification in the remaining nine Kalmia species exhibited a phylogenetic pattern, suggesting broad applicability of the markers across the genus.
Conclusions:
These microsatellite markers will be useful in population genetics and species boundaries studies of K. buxifolia, K. procumbens, and likely all other Kalmia species.publishedVersio
Microsatellite markers for the biogeographically enigmatic sandmyrtle (Kalmia buxifolia, Phyllodoceae: Ericaceae)
Premise:
Microsatellite markers were developed for sandmyrtle, Kalmia buxifolia (Ericaceae), to facilitate phylogeographic studies in this taxon and possibly many of its close relatives.
Methods and Results:
Fortyâeight primer pairs designed from pairedâend Illumina MiSeq data were screened for robust amplification. Sixteen pairs were amplified again, but with fluorescently labeled primers to facilitate genotyping. Resulting chromatograms were evaluated for variability using three populations from Tennessee, North Carolina, and New Jersey, USA. Eleven primer pairs were reliable and polymorphic (mean 3.92 alleles), one was reliable but monomorphic, and four were not reliable. The markers exhibited lower heterozygosity (mean 0.246) than expected (mean 0.464). Crossâamplification in the remaining nine Kalmia species exhibited a phylogenetic pattern, suggesting broad applicability of the markers across the genus.
Conclusions:
These microsatellite markers will be useful in population genetics and species boundaries studies of K. buxifolia, K. procumbens, and likely all other Kalmia species.publishedVersio
A Comparison of 1978 and 2006 Peak Pollen Seasons and Sampling Methods in Missoula, Montana
A study was conducted in Missoula, Montana to compare local pollen counts from 1978 with those measured nearly 30 years later in 2006 using two different measurement techniques (Durham gravimetric sampler and a Burkard volumetric sampler). Trends in peak pollen times measured during the spring, summer and autumn, respectively, were compared between the two years by Pearsonâs correlation and frequency of occurrence of plant genus. Meteorological conditions were also examined during each of the two study periods.
In comparing the two years, there was a statistically significant linear association between the different counts for the months of April through August, with similar levels of pollen types for any given month. The five predominant pollen types (based on counts) identified in each study were Pinus, Poaceae, Populus, Alnus, and Betula for 2006 and Pinus, Poaceae, Populus, Acer and Artemisia for 1978. In summary most of the genera displayed similar peak pollination timing between the two years, suggesting that results from the Durham (gravimetric) and Burkard (volumetric) sampling methods are comparable when reporting relative frequency of occurrence
Sharing and re-use of phylogenetic trees (and associated data) to facilitate synthesis
BACKGROUND Recently, various evolution-related journals adopted policies to encourage or require archiving of phylogenetic trees and associated data. Such attention to practices that promote sharing of data reflects rapidly improving information technology, and rapidly expanding potential to use this technology to aggregate and link data from previously published research. Nevertheless, little is known about current practices, or best practices, for publishing trees and associated data so as to promote re-use. FINDINGS Here we summarize results of an ongoing analysis of current practices for archiving phylogenetic trees and associated data, current practices of re-use, and current barriers to re-use. We find that the technical infrastructure is available to support rudimentary archiving, but the frequency of archiving is low. Currently, most phylogenetic knowledge is not easily re-used due to a lack of archiving, lack of awareness of best practices, and lack of community-wide standards for formatting data, naming entities, and annotating data. Most attempts at data re-use seem to end in disappointment. Nevertheless, we find many positive examples of data re-use, particularly those that involve customized species trees generated by grafting to, and pruning from, a much larger tree. CONCLUSIONS The technologies and practices that facilitate data re-use can catalyze synthetic and integrative research. However, success will require engagement from various stakeholders including individual scientists who produce or consume shareable data, publishers, policy-makers, technology developers and resource-providers. The critical challenges for facilitating re-use of phylogenetic trees and associated data, we suggest, include: a broader commitment to public archiving; more extensive use of globally meaningful identifiers; development of user-friendly technology for annotating, submitting, searching, and retrieving data and their metadata; and development of a minimum reporting standard (MIAPA) indicating which kinds of data and metadata are most important for a re-useable phylogenetic record
Sharing and re-use of phylogenetic trees (and associated data) to facilitate synthesis
Background
Recently, various evolution-related journals adopted policies to encourage or require archiving of phylogenetic trees and associated data. Such attention to practices that promote sharing of data reflects rapidly improving information technology, and rapidly expanding potential to use this technology to aggregate and link data from previously published research. Nevertheless, little is known about current practices, or best practices, for publishing trees and associated data so as to promote re-use. Findings
Here we summarize results of an ongoing analysis of current practices for archiving phylogenetic trees and associated data, current practices of re-use, and current barriers to re-use. We find that the technical infrastructure is available to support rudimentary archiving, but the frequency of archiving is low. Currently, most phylogenetic knowledge is not easily re-used due to a lack of archiving, lack of awareness of best practices, and lack of community-wide standards for formatting data, naming entities, and annotating data. Most attempts at data re-use seem to end in disappointment. Nevertheless, we find many positive examples of data re-use, particularly those that involve customized species trees generated by grafting to, and pruning from, a much larger tree. Conclusions
The technologies and practices that facilitate data re-use can catalyze synthetic and integrative research. However, success will require engagement from various stakeholders including individual scientists who produce or consume shareable data, publishers, policy-makers, technology developers and resource-providers. The critical challenges for facilitating re-use of phylogenetic trees and associated data, we suggest, include: a broader commitment to public archiving; more extensive use of globally meaningful identifiers; development of user-friendly technology for annotating, submitting, searching, and retrieving data and their metadata; and development of a minimum reporting standard (MIAPA) indicating which kinds of data and metadata are most important for a re-useable phylogenetic record
Validation of a New Predictive Risk Model: Measuring the Impact of the Major Modifiable Risks of Death for Patients and Populations
Background: Modifiable risks account for a large fraction of disease and death, but clinicians and patients lack tools to identify high risk populations or compare the possible benefit of different interventions.
Methods: We used data on the distribution of exposure to 12 major behavioral and biometric risk factors inthe US population, mortality rates by cause, and estimates of the proportional hazards of risk factor exposure from published systematic reviews to develop a risk prediction model that estimates an adult\u27s 10 year mortality risk compared to a population with optimum risk factors. We compared predicted risk to observed mortality in 8,241 respondents in NHANES 1988-1994 and NHANES 1999-2004 with linked mortality data up to the end of 2006
Small herbaria contribute unique biogeographic records to county, locality, and temporal scales
With digitization and data sharing initiatives underway over the last 15 years, an important need has been prioritizing specimens to digitize. Because duplicate specimens are shared among herbaria in exchange and gift programs, we investigated the extent to which unique biogeographic data are held in small herbaria vs. these data being redundant with those held by larger institutions. We evaluated the unique specimen contributions that small herbaria make to biogeographic understanding at county, locality, and temporal scales
Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis
Supported by the Global Alliance for TB Drug Development with support from the Bill and Melinda Gates Foundation, the European and Developing Countries Clinical Trials Partnership (Grant IP.2007.32011.011), US Agency for International Development, UK Department for International Development, Directorate General for International Cooperation of the Netherlands, Irish Aid, Australia Department of Foreign Affairs and Trade, National Institutes of Health, AIDS Clinical Trials Group. The study was also supported by grants from the National Institute of Allergy and Infectious Diseases (NIAID) (UM1AI068634, UM1 AI068636, and UM1AI106701) and by NIAID grants to the University of KwaZulu Natal, South Africa, AIDS Clinical Trials Group (ACTG) site 31422 (1U01AI069469); to the Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, South Africa, ACTG site 12301 (1U01AI069453); and to the Durban International Clinical Trials Unit, South Africa, ACTG site 11201 (1U01AI069426). Bayer Healthcare for donated moxifloxacin and Sanofi donated rifampin.Background:Â The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment. Methods:Â Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses. Results:Â Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31Â years (IQR 24â41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/ÎŒL (IQR 318â535). Pre-treatment spot samples had a higher yield of positive ZiehlâNeelsen smears (98% vs. 97%, Pâ=â0.02) and LJ cultures (87% vs. 82%, Pâ=â0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, Pâ=â0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1Â day, than spot samples in MGIT culture (4.5 vs. 5.5Â days, Pâ<â0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in KaplanâMeier analyses in either EMS or spot samples. Conclusions:Â Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples.Publisher PDFPeer reviewe
Target product profiles: tests for tuberculosis treatment monitoring and optimization
The World Health Organization has developed target product profiles containing minimum and optimum targets for key characteristics for tests for tuberculosis treatment monitoring and optimization. Tuberculosis treatment optimization refers to initiating or switching to an effective tuberculosis treatment regimen that results in a high likelihood of a good treatment outcome. The target product profiles also cover tests of cure conducted at the end of treatment. The development of the target product profiles was informed by a stakeholder survey, a cost-effectiveness analysis and a patient-care pathway analysis. Additional feedback from stakeholders was obtained by means of a Delphi-like process, a technical consultation and a call for public comment on a draft document. A scientific development group agreed on the final targets in a consensus meeting. For characteristics rated of highest importance, the document lists: (i) high diagnostic accuracy (sensitivity and specificity); (ii) time to result of optimally â€â2 hours and no more than 1 day; (iii) required sample type to be minimally invasive, easily obtainable, such as urine, breath, or capillary blood, or a respiratory sample that goes beyond sputum; (iv) ideally the test could be placed at a peripheral-level health facility without a laboratory; and (v) the test should be affordable to low- and middle-income countries, and allow wide and equitable access and scale-up. Use of these target product profiles should facilitate the development of new tuberculosis treatment monitoring and optimization tests that are accurate and accessible for all people being treated for tuberculosis
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