| 1. |
- Griffiths, Natalie A., et al.
(författare)
-
Temporal and Spatial Variation in Peatland Carbon Cycling and Implications for Interpreting Responses of an Ecosystem-Scale Warming Experiment
- 2017
-
Ingår i: Soil Science Society of America Journal. - : ACSESS. - 0361-5995 .- 1435-0661. ; 81:6, s. 1668-1688
-
Tidskriftsartikel (refereegranskat)abstract
- We are conducting a large-scale, long-term climate change response experiment in an ombrotrophic peat bog in Minnesota to evaluate the effects of warming and elevated CO2 on ecosystem processes using empirical and modeling approaches. To better frame future assessments of peatland responses to climate change, we characterized and compared spatial vs. temporal variation in measured C cycle processes and their environmental drivers. We also conducted a sensitivity analysis of a peatland C model to identify how variation in ecosystem parameters contributes to model prediction uncertainty. High spatial variability in C cycle processes resulted in the inability to determine if the bog was a C source or sink, as the 95% confidence interval ranged from a source of 50 g C m(-2) yr(-1) to a sink of 67 g C m(-2) yr(-1). Model sensitivity analysis also identified that spatial variation in tree and shrub photosynthesis, allocation characteristics, and maintenance respiration all contributed to large variations in the pretreatment estimates of net C balance. Variation in ecosystem processes can be more thoroughly characterized if more measurements are collected for parameters that are highly variable over space and time, and especially if those measurements encompass environmental gradients that may be driving the spatial and temporal variation (e.g., hummock vs. hollow microtopographies, and wet vs. dry years). Together, the coupled modeling and empirical approaches indicate that variability in C cycle processes and their drivers must be taken into account when interpreting the significance of experimental warming and elevated CO2 treatments.
|
|
| 2. |
- Jia, Qidong, et al.
(författare)
-
Microbial-type terpene synthase genes occur widely in nonseed land plants, but not in seed plants
- 2016
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 113:43, s. 12328-12333
-
Tidskriftsartikel (refereegranskat)abstract
- The vast abundance of terpene natural products in nature is due to enzymes known as terpene synthases (TPSs) that convert acyclic prenyl diphosphate precursors into a multitude of cyclic and acyclic carbon skeletons. Yet the evolution of TPSs is not well understood at higher levels of classification. Microbial TPSs from bacteria and fungi are only distantly related to typical plant TPSs, whereas genes similar to microbial TPS genes have been recently identified in the lycophyte Selaginella moellendorffii. The goal of this study was to investigate the distribution, evolution, and biochemical functions of microbial terpene synthase-like (MTPSL) genes in other plants. By analyzing the transcriptomes of 1,103 plant species ranging from green algae to flowering plants, putative MTPSL genes were identified predominantly from nonseed plants, including liverworts, mosses, hornworts, lycophytes, and monilophytes. Directed searching for MTPSL genes in the sequenced genomes of a wide range of seed plants confirmed their general absence in this group. Among themselves, MTPSL proteins from nonseed plants form four major groups, with two of these more closely related to bacterial TPSs and the other two to fungal TPSs. Two of the four groups contain a canonical aspartate-rich "DDxxD" motif. The third group has a "DDxxxD" motif, and the fourth group has only the first two "DD" conserved in this motif. Upon heterologous expression, representative members from each of the four groups displayed diverse catalytic functions as monoterpene and sesquiterpene synthases, suggesting these are important for terpene formation in nonseed plants.
|
|
| 3. |
- Weston, David J., et al.
(författare)
-
The Sphagnome Project : enabling ecological and evolutionary insights through a genus-level sequencing project
- 2018
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 217:1, s. 16-25
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ecologically relevant questions and hypotheses.
|
|
| 4. |
- Danchin, Nicolas, et al.
(författare)
-
Use, patient selection and outcomes of P2Y12 receptor inhibitor treatment in patients with STEMI based on contemporary European registries
- 2016
-
Ingår i: European Heart Journal - Cardiovascular Pharmacotherapy. - : Oxford University Press (OUP). - 2055-6837 .- 2055-6845. ; 2:3, s. 152-167
-
Tidskriftsartikel (refereegranskat)abstract
- Aims Among acute coronary syndromes (ACS), ST-segment elevation myocardial infarction (STEMI) has the most severe early clinical course. We aimed to describe the effectiveness and safety of P2Y12 receptor inhibitors in patients with STEMI based on the data from contemporary European ACS registries. Methods and results Twelve registries provided data in a systematic manner on outcomes in STEMI patients overall, and seven of these also provided data for P2Y12 receptor inhibitor-based dual antiplatelet therapy. The registrieswere heterogeneous in terms of site, patient, and treatment selection, as well as in definition of endpoints (e.g. bleeding events). All-cause death rates based on the data from 84 299 patients (9612 patients on prasugrel, 11 492 on ticagrelor, and 27 824 on clopidogrel) ranged between 0.49 and 6.68% in-hospital, between 3.07 and 7.95% at 30 days (reported in 6 registries), between 8.15 and 9.13% at 180 days, and between 2.41 and 9.58% at 1 year (5 registries). Major bleeding rates were 0.09-3.55% inhospital (8 registries), 0.09-1.65% at 30 days, and 1.96% at 1 year (only 1 registry). Fatal/life-Threatening bleeding was rare occurring between 0.08 and 0.13% in-hospital (4 registries) and 1.96% at 1 year (1 registry). Conclusions Real-world evidence from European contemporary registries shows that death, ischaemic events, and bleeding rates are lower than those reported in Phase III studies of P2Y12 inhibitors. Regarding individual P2Y12 inhibitors, patients on prasugrel, and, to a lesser degree, ticagrelor, had fewer ischaemic and bleeding events at all time points than clopidogrel-Treated patients. These findings are partly related to the fact that the newer agents are used in younger and less ill patients.
|
|
| 5. |
- Gupta, Kallol, et al.
(författare)
-
The role of interfacial lipids in stabilizing membrane protein oligomers
- 2017
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 541:7637, s. 421-424
-
Tidskriftsartikel (refereegranskat)abstract
- Oligomerization of membrane proteins in response to lipid binding has a critical role in many cell-signalling pathways(1) but is often difficult to define(2) or predict(3). Here we report the development of a mass spectrometry platform to determine simultaneously the presence of interfacial lipids and oligomeric stability and to uncover how lipids act as key regulators of membrane-protein association. Evaluation of oligomeric strength for a dataset of 125 alpha-helical oligomeric membrane proteins reveals an absence of interfacial lipids in the mass spectra of 12 membrane proteins with high oligomeric stability. For the bacterial homologue of the eukaryotic biogenic transporters (LeuT(4), one of the proteins with the lowest oligomeric stability), we found a precise cohort of lipids within the dimer interface. Delipidation, mutation of lipid-binding sites or expression in cardiolipin-deficient Escherichia coli abrogated dimer formation. Molecular dynamics simulation revealed that cardiolipin acts as a bidentate ligand, bridging across subunits. Subsequently, we show that for the Vibrio splendidus sugar transporter SemiSWEET(5), another protein with low oligomeric stability, cardiolipin shifts the equilibrium from monomer to functional dimer. We hypothesized that lipids are essential for dimerization of the Na+/H+ antiporter NhaA from E. coli, which has the lowest oligomeric strength, but not for the substantially more stable homologous Thermus thermophilus protein NapA. We found that lipid binding is obligatory for dimerization of NhaA, whereas NapA has adapted to form an interface that is stable without lipids. Overall, by correlating interfacial strength with the presence of interfacial lipids, we provide a rationale for understanding the role of lipids in both transient and stable interactions within a range of a-helical membrane proteins, including G-protein-coupled receptors.
|
|
| 6. |
- Hu, Xuchen, et al.
(författare)
-
GPIHBP1 expression in gliomas promotes utilization of lipoprotein-derived nutrients
- 2019
-
Ingår i: eLIFE. - : ELIFE SCIENCES PUBLICATIONS LTD. - 2050-084X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- GPIHBP1, a GPI-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) within the subendothelial spaces and shuttles it to the capillary lumen. GPIHBP1-bound LPL is essential for the margination of triglyceride-rich lipoproteins (TRLs) along capillaries, allowing the lipolytic processing of TRLs to proceed. In peripheral tissues, the intravascular processing of TRLs by the GPIHBP1-LPL complex is crucial for the generation of lipid nutrients for adjacent parenchymal cells. GPIHBP1 is absent from the capillaries of the brain, which uses glucose for fuel; however, GPIHBP1 is expressed in the capillaries of mouse and human gliomas. Importantly, the GPIHBP1 in glioma capillaries captures locally produced LPL. We use NanoSIMS imaging to show that TRLs marginate along glioma capillaries and that there is uptake of TRL-derived lipid nutrients by surrounding glioma cells. Thus, GPIHBP1 expression in gliomas facilitates TRL processing and provides a source of lipid nutrients for glioma cells.
|
|
| 7. |
- Lettino, Maddalena, et al.
(författare)
-
Diabetic patients with acute coronary syndromes in contemporary European registries : Characteristics and outcomes
- 2017
-
Ingår i: European Heart Journal - Cardiovascular Pharmacotherapy. - : Oxford University Press (OUP). - 2055-6837 .- 2055-6845. ; 3:4, s. 198-213
-
Tidskriftsartikel (refereegranskat)abstract
- Aims Among patients with acute coronary syndromes (ACS), those with diabetes mellitus (DM) are at particularly high risk of recurrent cardiovascular events and premature death. We aimed to provide a descriptive overview of unadjusted analyses of patient characteristics, ACS management, and outcomes up to 1 year after hospital admission for an ACS/index-ACS event, in patients with DM in contemporary registries in Europe. Methods and results A total of 10 registries provided data in a systematic manner on ACS patients with DM (total n =28 899), and without DM (total n= 97 505). In the DM population, the proportion of patients with ST-Segment Elevation Myocardial Infarction (STEMI) ranged from 22.1% to 64.6% (other patients had non-ST-Segment Elevation Myocardial Infarction (NSTEMI-ACS) or unstable angina). All-cause mortality in the registries ranged from 1.4% to 9.4% in-hospital; 2.8% to 7.9% at 30 days post-discharge; 5.1% to 10.7% at 180 days post-discharge; and 3.3% to 10.5% at 1 year post-discharge. Major bleeding events were reported in up to 3.8% of patients while in hospital (8 registries); up to 1.3% at 30 days (data from two registries only), and 2.0% at 1 year (one registry only). Registries differed substantially in terms of study setting, site, patient selection, definition and schedule of endpoints, and use of various P2Y12 inhibitors. In most, but not all, registries, event rates in DM patients were higher than in patients without DM. Pooled risk ratios comparing cohorts with DM vs. no DM were in-hospital significantly higher in DM for all-cause death (1.66; 95% CI 1.42-1.94), for cardiovascular death (2.33; 1.78 - 3.03), and for major bleeding (1.35; 1.21-1.52). Conclusion These registry data from real-life clinical practice confirm a high risk for recurrent events among DM patients with ACS, with great variation across the different registries.
|
|
| 8. |
- Norby, Richard J., et al.
(författare)
-
Informing models through empirical relationships between foliar phosphorus, nitrogen and photosynthesis across diverse woody species in tropical forests of Panama
- 2017
-
Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 215:4, s. 1425-1437
-
Tidskriftsartikel (refereegranskat)abstract
- Our objective was to analyze and summarize data describing photosynthetic parameters and foliar nutrient concentrations from tropical forests in Panama to inform model representation of phosphorus (P) limitation of tropical forest productivity.Gas exchange and nutrient content data were collected from 144 observations of upper canopy leaves from at least 65 species at two forest sites in Panama, differing in species composition, rainfall and soil fertility. Photosynthetic parameters were derived from analysis of assimilation rate vs internal CO2 concentration curves (A/Ci), and relationships with foliar nitrogen (N) and P content were developed.The relationships between area-based photosynthetic parameters and nutrients were of similar strength for N and P and robust across diverse species and site conditions. The strongest relationship expressed maximum electron transport rate (Jmax) as a multivariate function of both N and P, and this relationship was improved with the inclusion of independent data on wood density.Models that estimate photosynthesis from foliar N would be improved only modestly by including additional data on foliar P, but doing so may increase the capability of models to predict future conditions in P-limited tropical forests, especially when combined with data on edaphic conditions and other environmental drivers.
|
|
| 9. |
|
|
| 10. |
- Schuettpelz, Eric, et al.
(författare)
-
A community-derived classification for extant lycophytes and ferns
- 2016
-
Ingår i: Journal of Systematics and Evolution. - : Wiley. - 1674-4918 .- 1759-6831. ; 54:6, s. 563-603
-
Tidskriftsartikel (refereegranskat)abstract
- Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community-based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.
|
|
