51 research outputs found
Genotypic Diversity and Host-Specificity of Frankia Bacteria Associated with Sympatric Populations of Alnus rubra and Alnus rhombifolia in Oregon
Biological nitrogen fixation is one of the most critical processes contributing to ecosystem productivity and stability on a global scale. In temperate climates of the northern hemisphere, plant-root associated bacteria of the genus Frankia are the major nitrogen fixers in forest environments. Trees belonging to the genus Alnus are the most widespread hosts of Frankia in the Pacific Northwest, and a myriad of biotic and abiotic factors can influence the robustness of this symbiosis. Host identity and bacterial strain are important features that can impact Alnus-Frankia association, but little is known about the interplay of intrageneric hosts that co-occur in natural settings. In this study we investigated the genetic diversity and host specificity of Frankia bacteria associated with sympatrically occurring populations of Alnus rubra (red alder) and Alnus rhombifolia (white alder) in Oregon. Based on sequence analysis of the nifH gene recovered from root nodules we found low overall bacterial diversity. One dominant Frankia genotype was associated with both host species, indicating a lack of strong host specificity in this system. Our results suggest that certain intrageneric plant hosts with overlapping distributions show cross-compatibility with symbiotic actinorhizal bacteria, and that low strain diversity of these bacteria can persist across mixed host populations
Yeast homotypic vacuole fusion requires the Ccz1âMon1 complex during the tethering/docking stage
The function of the yeast lysosome/vacuole is critically linked with the morphology of the organelle. Accordingly, highly regulated processes control vacuolar fission and fusion events. Analysis of homotypic vacuole fusion demonstrated that vacuoles from strains defective in the CCZ1 and MON1 genes could not fuse. Morphological evidence suggested that these mutant vacuoles could not proceed to the tethering/docking stage. Ccz1 and Mon1 form a stable protein complex that binds the vacuole membrane. In the absence of the Ccz1âMon1 complex, the integrity of vacuole SNARE pairing and the unpaired SNARE class C Vps/HOPS complex interaction were both impaired. The Ccz1âMon1 complex colocalized with other fusion components on the vacuole as part of the cis-SNARE complex, and the association of the Ccz1âMon1 complex with the vacuole appeared to be regulated by the class C Vps/HOPS complex proteins. Accordingly, we propose that the Ccz1âMon1 complex is critical for the Ypt7-dependent tethering/docking stage leading to the formation of a trans-SNARE complex and subsequent vacuole fusion
Neither a novel tau proteinopathy nor an expansion of a phenotype: Reappraising clinicopathology-based nosology
The gold standard for classification of neurodegenerative diseases is postmortem histopathol-ogy; however, the diagnostic odyssey of this case challenges such a clinicopathologic model. We evaluated a 60-year-old woman with a 7-year history of a progressive dystoniaâataxia syndrome with supranuclear gaze palsy, suspected to represent NiemannâPick disease Type C. Postmortem evaluation unexpectedly demonstrated neurodegeneration with 4-repeat tau deposition in a distribution diagnostic of progressive supranuclear palsy (PSP). Whole-exome sequencing revealed a new het-erozygous variant in TGM6, associated with spinocerebellar ataxia type 35 (SCA35). This novel TGM6 variant reduced transglutaminase activity in vitro, suggesting it was pathogenic. This case could be interpreted as expanding: (1) the PSP phenotype to include a spinocerebellar variant; (2) SCA35 as a tau proteinopathy; or (3) TGM6 as a novel genetic variant underlying a SCA35 phenotype with PSP pathology. None of these interpretations seem adequate. We instead hypothesize that impairment in the crosslinking of tau by the TGM6-encoded transglutaminase enzyme may compromise tau functionally and structurally, leading to its aggregation in a pattern currently classified as PSP. The lessons from this case study encourage a reassessment of our clinicopathology-based nosology.Fil: Marsili, Luca. University of Cincinnati; Estados UnidosFil: Sharma, Jennifer. University of Cincinnati; Estados UnidosFil: Espay, Alberto J.. University of Cincinnati; Estados UnidosFil: Migazzi, Alice. Universita degli Studi di Trento; ItaliaFil: Abdelghany, Elhusseini. University of Cincinnati; Estados UnidosFil: Hill, Emily J.. University of Cincinnati; Estados UnidosFil: Duque, Kevin R.. University of Cincinnati; Estados UnidosFil: Hagen, Matthew C.. University of Cincinnati; Estados UnidosFil: Stephen, Christopher D.. Harvard Medical School; Estados UnidosFil: Kovacs, Gabor G.. University of Toronto; CanadĂĄFil: Lang, Anthony E.. University of Toronto; CanadĂĄFil: Hadjivassiliou, Marios. University Of Sheffield (university Of Sheffield);Fil: Basso, Manuela. Universita degli Studi di Trento; ItaliaFil: Kauffman, Marcelo Andres. Universidad Austral. Facultad de Ciencias BiomĂ©dicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Sturchio, Andrea. University of Cincinnati; Estados Unido
Vac8p, an Armadillo Repeat Protein, Coordinates Vacuole Inheritance With Multiple Vacuolar Processes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74978/1/j.1600-0854.2006.00458.x.pd
Constructing the extended Haagerup planar algebra
We construct a new subfactor planar algebra, and as a corollary a new
subfactor, with the `extended Haagerup' principal graph pair. This completes
the classification of irreducible amenable subfactors with index in the range
, which was initiated by Haagerup in 1993. We prove that the
subfactor planar algebra with these principal graphs is unique. We give a skein
theoretic description, and a description as a subalgebra generated by a certain
element in the graph planar algebra of its principal graph. In the skein
theoretic description there is an explicit algorithm for evaluating closed
diagrams. This evaluation algorithm is unusual because intermediate steps may
increase the number of generators in a diagram.Comment: 45 pages (final version; improved introduction
Recommended from our members
Estimating Global ââBlue Carbonââ Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems
Recent attention has focused on the high rates of annual carbon sequestration in vegetated coastal ecosystemsâmarshes, mangroves, and seagrassesâthat may be lost with habitat destruction (âconversionâ). Relatively unappreciated, however, is that conversion of these coastal ecosystems also impacts very large pools of previously-sequestered carbon. Residing mostly in sediments, this âblue carbonâ can be released to the atmosphere when these ecosystems are converted or degraded. Here we provide the first global estimates of this impact and evaluate its economic implications. Combining the best available data on global area, land-use conversion rates, and near-surface carbon stocks in each of the three ecosystems, using an uncertainty-propagation approach, we estimate that 0.15â1.02 Pg (billion tons) of carbon dioxide are being released annually, several times higher than previous estimates that account only for lost sequestration. These emissions are equivalent to 3â19% of those from deforestation globally, and result in economic damages of $US 6â42 billion annually. The largest sources of uncertainty in these estimates stems from limited certitude in global area and rates of land-use conversion, but research is also needed on the fates of ecosystem carbon upon conversion. Currently, carbon emissions from the conversion of vegetated coastal ecosystems are not included in emissions accounting or carbon market protocols, but this analysis suggests they may be disproportionally important to both. Although the relevant science supporting these initial estimates will need to be refined in coming years, it is clear that policies encouraging the sustainable management of coastal ecosystems could significantly reduce carbon emissions from the land-use sector, in addition to sustaining the well-recognized ecosystem services of coastal habitats
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Multi-ancestry genome-wide association meta-analysis of Parkinson?s disease
Although over 90 independent risk variants have been identified for Parkinsonâs disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinsonâs disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations
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