115 research outputs found
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A Copper-Mediated Conjugate Addition Approach to Analogues of Aconitine-Type Diterpenoid Alkaloids.
A copper-mediated conjugate addition of electron-rich aryl groups into a complex vinyl nitrile using arylmagnesium bromides is reported. The conjugate addition adducts were advanced toward the synthesis of designed aconitine-type analogues. The variation in oxygenation patterns on the arene coupling partner, introduced through the current conjugate addition approach, may ultimately provide insight into structure-activity relationships of the diterpenoid alkaloids
Distribution, functional impact, and origin mechanisms of copy number variation in the barley genome
BACKGROUND There is growing evidence for the prevalence of copy number variation (CNV) and its role in phenotypic variation in many eukaryotic species. Here we use array comparative genomic hybridization to explore the extent of this type of structural variation in domesticated barley cultivars and wild barleys. RESULTS A collection of 14 barley genotypes including eight cultivars and six wild barleys were used for comparative genomic hybridization. CNV affects 14.9% of all the sequences that were assessed. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. CNVs are enriched near the ends of all chromosomes except 4H, which exhibits the lowest frequency of CNVs. CNV affects 9.5% of the coding sequences represented on the array and the genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases. Sequence-based comparisons of CNV between cultivars Barke and Morex provided evidence that DNA repair mechanisms of double-strand breaks via single-stranded annealing and synthesis-dependent strand annealing play an important role in the origin of CNV in barley. CONCLUSIONS We present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley, and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance. We also identify potential mechanisms that can generate variation in copy number in plant genomes.This work was financially supported by the following grants:
project GABI-BARLEX, German Federal Ministry of Education and Research
(BMBF), #0314000 to MP, US, KFXM and NS; Triticeae Coordinated
Agricultural Project, USDA-NIFA #2011-68002-30029 to GJM; and Agriculture
and Food Research Initiative Plant Genome, Genetics and Breeding Program
of USDAâs Cooperative State Research and Extension Service, #2009-65300-
05645 to GJM
Clinical Study of Ursodeoxycholic Acid in Barrett's Esophagus Patients
Prior research strongly implicates gastric acid and bile acids, two major components of the gastroesophageal refluxate, in the development of Barrettâs esophagus (BE) and its pathogenesis. Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, has been shown to protect esophageal cells against oxidative stress induced by cytotoxic bile acids. We conducted a pilot clinical study to evaluate the clinical activity of UDCA in patients with BE. Twenty-nine BE patients received UDCA treatment at a daily dose of 13â15 mg/kg/day for six months. The clinical activity of UDCA was assessed by evaluating changes in gastric bile acid composition and markers of oxidative DNA damage (8-hydroxydeoxyguanosine, 8OHdG), cell proliferation (Ki67), and apoptosis (cleaved caspase 3, CC3) in BE epithelium. The bile acid concentrations in gastric fluid were measured by liquid chromatography-mass spectrometry. At baseline, UDCA (sum of unchanged and glycine/taurine conjugates) accounted for 18.2% of total gastric bile acids. Post UDCA intervention, UDCA increased significantly to account for 93.39% of total gastric bile acids (p<0.0001). The expression of markers of oxidative DNA damage, cell proliferation, and apoptosis was assessed in the BE biopsies by immunohistochemistry. The selected tissue biomarkers were unchanged after 6 months of UDCA intervention. We conclude that high dose UDCA supplementation for six months resulted in favorable changes in gastric bile acid composition but did not modulate selected markers of oxidative DNA damage, cell proliferation, and apoptosis in the BE epithelium
Dependence of neutral winds on convection Eâfield, solar EUV, and auroral particle precipitation at high latitudes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94962/1/jgra18137.pd
Possible reasons for underestimating Joule heating in global models: E field variability, spatial resolution, and vertical velocity
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95611/1/jgra18607.pd
Maternal Exposure to Nitrogen Dioxide, Intake of Methyl Nutrients, and Congenital Heart Defects in Offspring
Nutrients that regulate methylation processes may modify susceptibility to the effects of air pollutants. Data from the National Birth Defects Prevention Study (United States, 1997-2006) were used to estimate associations between maternal exposure to nitrogen dioxide (NO2), dietary intake of methyl nutrients, and the odds of congenital heart defects in offspring. NO2 concentrations, a marker of traffic-related air pollution, averaged across postconception weeks 2-8, were assigned to 6,160 nondiabetic mothers of cases and controls using inverse distance-squared weighting of air monitors within 50 km of maternal residences. Intakes of choline, folate, methionine, and vitamins B6 and B12 were assessed using a food frequency questionnaire. Hierarchical regression models, which accounted for similarities across defects, were constructed, and relative excess risks due to interaction were calculated. Relative to women with the lowest NO2 exposure and high methionine intake, women with the highest NO2 exposure and lowest methionine intake had the greatest odds of offspring with a perimembranous ventricular septal defect (odds ratio = 3.23, 95% confidence interval: 1.74, 6.01; relative excess risk due to interaction = 2.15, 95% confidence interval: 0.39, 3.92). Considerable departure from additivity was not observed for other defects. These results provide modest evidence of interaction between nutrition and NO2 exposure during pregnancy
Distribution, functional impact, and origin mechanisms of copy number variation in the barley genome
BACKGROUND: There is growing evidence for the prevalence of copy number variation (CNV) and its role in phenotypic variation in many eukaryotic species. Here we use array comparative genomic hybridization to explore the extent of this type of structural variation in domesticated barley cultivars and wild barleys. RESULTS: A collection of 14 barley genotypes including eight cultivars and six wild barleys were used for comparative genomic hybridization. CNV affects 14.9% of all the sequences that were assessed. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. CNVs are enriched near the ends of all chromosomes except 4H, which exhibits the lowest frequency of CNVs. CNV affects 9.5% of the coding sequences represented on the array and the genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases. Sequence-based comparisons of CNV between cultivars Barke and Morex provided evidence that DNA repair mechanisms of double-strand breaks via single-stranded annealing and synthesis-dependent strand annealing play an important role in the origin of CNV in barley. CONCLUSIONS: We present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley, and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance. We also identify potential mechanisms that can generate variation in copy number in plant genomes
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Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam Sluiceway, 2005
The U.S. Army Corps of Engineers Portland District engaged the Pacific Northwest National Laboratory to evaluate fish passage at The Dalles Dam powerhouse in 2005. The goal of the study was to provide information on smolt passage that will inform decisions on long-term measures and operations to enhance sluiceway passage and reduce turbine passage to improve smolt survival at the dam. The study addressed one of the main programs dedicated to improving juvenile salmonid survival at The Dalles Dam: Surface Flow Bypass. The study objectives (see below) were met using a combination of hydroacoustic and hydraulic data. The study incorporated fixed-location hydroacoustic methods across the entire powerhouse, with especially intense sampling using multiple split-beam transducers at all sluiceway portals. We did not sample fish passage at the spillway in 2005. In the sluiceway nearfield, we used an acoustic camera to track fish movements. The fish data were interpreted with hydraulic data from a computational fluid dynamics (CFD) model. Fish passage data were collected in the framework of an âexperimentâ using a randomized block design (3-day treatments; two treatments) to compare two sluiceway operational configurations: Sluice 2+5 and Sluice 2+19 (six gates open for each configuration). Total project outflow was 76% of the 10-year average for spring and 71% of the 10-year average for summer. Based on these findings, we make the following recommendations: 1) The sluice should be operated 24 h/d from April until November. 2) Open six rather than three sluice gates to take advantage of the maximum hydraulic capacity of the sluiceway. 3) Open the three gates above the western-most operating main turbine unit and the three gates at MU 8 where turbine passage rates are relatively high. 4) Operate the turbine units below open sluice gates as a standard fish operations procedure. 5) Develop hydraulic and entrance enhancements to the sluiceway to tap the potential of The Dalles Dam sluiceway to be highly efficient and effective at passing juvenile salmonids. 6) Consider the following elements for surface flow bypasses during design of any sluiceway enhancements at The Dalles Dam: Form an extensive surface flow bypass flow net (surface bypass discharge greater than ~7% of total project discharge) at both west and east ends of the dam; Create a gradual increase in water velocity approaching the surface flow bypass (ideally, acceleration 3 m/s) to entrain the subject juvenile fishes, e.g., 10,000 cfs or so; Adapt the shape and orientation of the surface entrance(s) to fit site-specific features, i.e., test a Removable Sluiceway Weir. 7)The Dalles Dam sluiceway has potential to be highly efficient and effective at passing juvenile salmonids. We recommend tapping this potential with enhancements to the sluiceway
Ablation of prion protein immunoreactivity by heating in saturated calcium hydroxide
<p>Abstract</p> <p>Background</p> <p>Prions, the infectious agents that cause transmissible spongiform encephalopathies (TSEs), are relatively resistant to destruction by physical, enzymatic, and chemical treatments. Hydrolysis in boiling saturated calcium hydroxide (limewater) utilizes inexpensive chemicals to digest protein components of offal. The purpose of this work was to determine if incubating brain material from scrapie-infected sheep in near-boiling saturated calcium hydroxide solution (Ca(OH)<sub>2</sub>) would abolish immunoreactivity of the infectious prion (PrP<sup>Sc</sup>) as determined by western blot.</p> <p>Findings</p> <p>After incubating for as few as 10 minutes in saturated calcium hydroxide at 99°C, immunoreactivity of protease resistant bands by western blot analysis is completely lost.</p> <p>Conclusion</p> <p>Boiling in limewater may offer an alternative for disposal of carcasses and enable alternative uses for rendered products from potentially infected carcasses.</p
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