Manganese triggers phosphorylation-mediated endocytosis of the Arabidopsis metal transporter NRAMP1.

The NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 1 (NRAMP1) transporter guarantees plant survival of manganese (Mn) deficiency by mediating Mn entry into root cells. Unlike other high-affinity metal transporters, NRAMP1 is only slightly regulated at the transcriptional level. We show here that adequate Mn content in tissues is safeguarded through a tight control of the quantity of NRAMP1 present at the surface of root cells. Depending on Mn availability, an NRAMP1-GFP fusion protein cycles dynamically between the plasma membrane (PM) and endosomal compartments. This involves a clathrin-mediated endocytosis pathway, as disrupting this pathway in auxilin-overexpressor lines prevents NRAMP1 internalization. Mutation of the phosphorylated serine residues 20, 22 and 24 in the cytosol-exposed N terminus of NRAMP1 alters its membrane distribution. Indeed, a phospho-dead mutation stabilizes NRAMP1 at the PM, regardless of the Mn regime, and dramatically reduces plant tolerance to Mn toxicity. Conversely a phosphomimetic mutant is constitutively internalized into endosomes. Together, these data establish that phosphorylation of NRAMP1 is the trigger for its Mn-induced endocytosis and represents the main level of regulation of this transporter. Furthermore, the extent of Mn toxicity observed when interrupting NRAMP1 membrane cycling undermines the dogma that Mn is only marginally toxic to plants.

Global effects of land use on local terrestrial biodiversity.

Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.

Intracellular Distribution of Manganese by the Trans-Golgi Network Transporter NRAMP2 Is Critical for Photosynthesis and Cellular Redox Homeostasis.

Plants require trace levels of manganese (Mn) for survival, as it is an essential cofactor in oxygen metabolism, especially O2 production via photosynthesis and the disposal of superoxide radicals. These processes occur in specialized organelles, requiring membrane-bound intracellular transporters to partition Mn between cell compartments. We identified an Arabidopsis thaliana member of the NRAMP family of divalent metal transporters, NRAMP2, which functions in the intracellular distribution of Mn. Two knockdown alleles of NRAMP2 showed decreased activity of photosystem II and increased oxidative stress under Mn-deficient conditions, yet total Mn content remained unchanged. At the subcellular level, these phenotypes were associated with a loss of Mn content in vacuoles and chloroplasts. NRAMP2 was able to rescue the mitochondrial yeast mutant mtm1∆ In plants, NRAMP2 is a resident protein of the trans-Golgi network. NRAMP2 may act indirectly on downstream organelles by building up a cytosolic pool that is used to feed target compartments. Moreover, not only does the nramp2 mutant accumulate superoxide ions, but NRAMP2 can functionally replace cytosolic superoxide dismutase in yeast, indicating that the pool of Mn displaced by NRAMP2 is required for the detoxification of reactive oxygen species.

Do natural enemies explain fluctuations in low-density spruce budworm populations?

Understanding the causal pathways through which forest insect outbreaks are triggered is important for resource managers. However, detailed population dynamics studies are hard to conduct in low-density, pre-outbreak populations because the insects are difficult to sample in sufficient numbers. Using laboratory-raised larvae installed in the field across a 1,000 km east-west gradient in Québec (Canada) over an 11-yr period, we examined if parasitism and predation were likely to explain fluctuations in low-density spruce budworm (Choristoneura fumiferana; SBW) populations. Parasitism rates by the two main larval parasitoid species, Elachertus cacoeciae and Tranosema rostrale, peaked during different years. This suggests that temporal fluctuations in overall parasitism were partly buffered by compensatory dynamics among parasitoid species. Still, spatial covariance analyses indicate that the residual interannual variation in parasitism rates was substantial and correlated over large distances (up to 700 km). On the other hand, interannual variation in predation rates was not spatially correlated. Piecewise structural equation models indicate that temporal variation in parasitism and predation does not influence temporal variation in wild SBW abundance. Spatially, however, SBWs installed in warmer locations tended to show higher parasitism rates, and these higher rates correlated with lower wild SBW population levels. Overall, the results indicate that large-scale drops in parasitism occur and could potentially contribute to SBW population increases. However, during the period covered by this study, other factors such as direct effects of weather on SBW larval development or indirect effects through host tree physiology or phenology were more likely to explain large-scale variation in wild SBW populations.

Unfertilized ovary pushes wheat flower open for cross-pollination.

Bread wheat is strongly autogamous; however, an opportunity for outcrossing occurs when self-pollination fails and florets open. The first phase of floret opening at anthesis is short and induced by lodicule turgidity. Some wheat florets re-open post-anthesis for several days, known as the 'second opening', for which the underlying mechanisms are largely unknown. We performed detailed physiological, anatomical, and histological investigations to understand the biological basis of the flower opening process. Wheat florets were observed open when the ovary was unfertilized. Unfertilized ovaries significantly increased in radial size post-anthesis, pushing the lemma and palea apart to open the florets. The absence of fertile pollen was not directly linked to this, but anther filament elongation coincided with initiation of ovary swelling. The pericarp of unfertilized ovaries did not undergo degeneration as normally seen in developing grains, instead pericarp cells remained intact and enlarged, leading to increased ovary radial size. This is a novel role for the ovary pericarp in wheat flower opening, and the knowledge is useful for facilitating cross-pollination in hybrid breeding. Ovary swelling may represent a survival mechanism in autogamous cereals such as wheat and barley, ensuring seed set in the absence of self-fertilization and increasing genetic diversity through cross-pollination.

Response diversity, functional redundancy, and post-logging productivity in northern temperate and boreal forests.

The development of efficient ecosystem resilience indicators was identified as one of the key research priorities in the improvement of existing sustainable forest management frameworks. Two indicators of tree diversity associated with ecosystem functioning have recently received particular attention in the literature: functional redundancy (FR) and response diversity (RD). We examined how these indicators could be used to predict post-logging productivity in forests of Québec, Canada. We analysed the relationships between pre-logging FR and RD, as measured with sample plots, and post-logging productivity, measured as seasonal variation in enhanced vegetation index obtained from MODIS satellite imagery. The effects of the deciduous and coniferous tree components in our pre-disturbance diversity assessments were isolated in order to examine the hypothesis that they have different impacts on post-disturbance productivity. We also examined the role of tree species richness and species identity effects. Our analysis revealed the complementary nature of traditional biodiversity indicators and trait-based approaches in the study of biodiversity-ecosystem-functioning relationships in dynamic ecosystems. We report a significant and positive relationship between pre-disturbance deciduous RD and post-disturbance productivity, as well as an unexpected significant negative effect of coniferous RD on productivity. This negative relationship with post-logging productivity likely results from slower coniferous regeneration speeds and from the relatively short temporal scale examined. Negative black-spruce-mediated identity effects were likely associated with increased stand vulnerability to paludification and invasion by ericaceous shrubs that slow down forest regeneration. Response diversity outperformed functional redundancy as a measure of post-disturbance productivity most likely due to the stand-replacing nature of the disturbance considered. To the best of our knowledge, this is among the first studies to report a negative significant relationship between a component of RD and ecosystem functioning, namely coniferous RD and forest ecosystem productivity after a stand-replacing disturbance.

The n-queens completion problem.

An n-queens configuration is a placement of n mutually non-attacking queens on an n × n chessboard. The n-queens completion problem, introduced by Nauck in 1850, is to decide whether a given partial configuration can be completed to an n-queens configuration. In this paper, we study an extremal aspect of this question, namely: how small must a partial configuration be so that a completion is always possible? We show that any placement of at most n/60 mutually non-attacking queens can be completed. We also provide partial configurations of roughly n/4 queens that cannot be completed and formulate a number of interesting problems. Our proofs connect the queens problem to rainbow matchings in bipartite graphs and use probabilistic arguments together with linear programming duality.

Clinical Importance of Graft Integrity in Arthroscopic Superior Capsular Reconstruction Using a Minimally Invasively Harvested Midthigh Fascia Lata Autograft: 3-Year Clinical and Magnetic Resonance Imaging Outcomes.

BACKGROUND: The clinical importance of graft type and integrity in arthroscopic superior capsular reconstruction (ASCR) remains controversial. PURPOSE: To assess 3-year clinical and magnetic resonance imaging (MRI) outcomes of ASCR using a minimally invasively harvested fascia lata autograft (FLA) for irreparable rotator cuff tears (IRCTs) and to determine the clinical importance of graft integrity and whether the results change from year 2 to 3. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 22 consecutive patients who underwent ASCR with a minimally invasively harvested FLA were enrolled in a prospective single-arm study. At 3 years, the patients answered a satisfaction questionnaire and underwent a clinical examination and MRI. The MRI scans were independently reviewed by 3 raters to determine the graft integrity, acromiohumeral interval, supraspinatus atrophy, and fatty degeneration of the rotator cuff muscles. Reliability statistics were calculated, and the outcomes were compared across subgroups of patients with and without complete graft tears. RESULTS: Overall, 21 patients (95.5%) answered the questionnaire, 20/21 (95.2%) were satisfied, 4/20 (20.0%) reported donor site pain, and 19 patients (86.4%) underwent examinations. From preoperatively to 3 years, the mean improvement was 73.68° in elevation (95% CI, 47.59°-99.77°), 89.21° in abduction (95% CI, 66.56°-111.86°), 24.74° in external rotation (95% CI, 4.72°-34.75°), 3.00 in internal rotation (95% CI, 2.36-3.64), 2.61 kg in abduction strength (95% CI, 1.76-3.45 kg), 50.79 on the Constant score (CS; 95% CI, 41.99-59.58), 7.47 on the Simple Shoulder Test (SST; 95% CI, 5.19-9.75), and 36.05% on the subjective shoulder value (SSV; 95% CI, 23.19%-48.92%), which were all significant (P < .05). From 2 to 3 years, the mean improvement in abduction was 20.26° (95% CI, 5.44°-35.09°), which was significant (P = .010). At 3 years, the raters perfectly agreed (kappa = 1; P = .000013) that 4 patients (21.1%) had complete graft tears; this subgroup of patients had decreased external rotation strength at 90° of abduction (1.77 ± 0.17 vs 4.45 ± 2.55 kg, respectively; P = .027) and increased grades of infraspinatus (3.50 ± 0.58 vs 2.20 ± 1.01, respectively; P = .030) and teres minor fatty degeneration (3.25 ± 0.96 vs 1.53 ± 0.64, respectively; P = .005) compared with those without a complete graft tear, but the mean CS, SST, and SSV scores did not differ from those of the overall group (69.50 ± 5.20 vs 69.63 ± 18.25; 9.00 ± 2.31 vs 9.74 ± 4.73; and 72.50 ± 15.00 vs 71.58 ± 26.70, respectively). CONCLUSION: The 3-year clinical outcomes of ASCR using a minimally invasively harvested FLA for IRCTs were good, despite donor site morbidity. Active abduction improved significantly from 2 to 3 years. Complete graft tears were correlated with significantly decreased external rotation strength at 90° of shoulder abduction and increased grades of infraspinatus and teres minor fatty degeneration. REGISTRATION: NCT03663036 (ClinicalTrials.gov identifier).

Risk stratification in normotensive acute pulmonary embolism patients: focus on the intermediate-high risk subgroup.

BACKGROUND: Patients with acute pulmonary embolism are at intermediate-high risk in the presence of imaging signs of right ventricular dysfunction plus one or more elevated cardiac biomarker. We hypothesised that intermediate-high risk patients with two elevated cardiac biomarkers and imaging signs of right ventricular dysfunction have a worse prognosis than those with one cardiac biomarker and imaging signs of right ventricular dysfunction. METHODS: We analysed the cumulative presence of cardiac biomarkers and imaging signs of right ventricular dysfunction in 525 patients with intermediate risk pulmonary embolism (intermediate-high risk = 237) presenting at the emergency department in two centres. Studied endpoints were composites of all-cause mortality and/or rescue thrombolysis at 30 days (primary endpoint; n=58) and pulmonary embolism-related mortality and/or rescue thrombolysis at 30 days (secondary endpoint; n=40). RESULTS: Patients who experienced the primary endpoint showed a higher proportion of elevated troponin (47% vs. 76%, P<0.001), elevated N-terminal pro-brain natriuretic peptide (67% vs. 93%, P<0.001) and imaging signs of right ventricular dysfunction (47% vs. 80%, P<0.001). Multivariate analysis revealed N-terminal pro-brain natriuretic peptide (hazard ratio (HR) 3.6, 95% confidence interval (CI) 1.3-10.3; P=0.015) and imaging signs of right ventricular dysfunction (HR 2.8, 95% CI 1.5-5.2; P=0.001) as independent predictors of events. In the intermediate-high risk group, patients with two cardiac biomarkers performed worse than those with one cardiac biomarker (HR 3.3, 95% CI 1.8-6.2; P=0.003). CONCLUSIONS: Risk stratification in normotensive pulmonary embolism should consider the cumulative presence of cardiac biomarkers and imaging signs of right ventricular dysfunction, especially in the intermediate-high risk subgroup.

Are we overcalling sacroiliitis on MRI? Differential diagnosis that every rheumatologist should know - Part I.

Diagnosing early spondyloarthritis remains a challenge in routine practice, especially in its axial (SpA) form. Magnetic resonance imaging (MRI) is capable of detecting early bone marrow edema (BME) in the sacroiliac joints (SIJs), a key criterion for the diagnosis of active SpA according to the "imaging arm" of the Assessment of Spondyloarthritis International Society (ASAS) classification. However, despite MRI having superior reliability compared to radiographs and being recognized as a crucial imaging biomarker of SpA, it has several limitations, including its limited specificity and sensitivity. Based on the established literature, there is currently an "overcall" of sacroiliitis on MRIs. In this setting, differential diagnoses and their imaging features come into play. In this two-part article, we will review both the imaging features that constitute a "positive" MRI in SpA and the most common differential diagnoses. In order to understand the pathophysiology of sacroiliitis and the spectrum of developing lesions, one needs to be familiar with the complex SIJs anatomy, both on radiographs and on cross-sectional imaging studies (particularly MRI). As such, in the first part of this article, we provide a brief background on anatomy and different imaging modalities used in this clinical setting and we review the imaging criteria for a "positive" MRI study of sacroiliitis in adults (imaging arm of the ASAS classification).

Are We Overcalling Sacroillitis on MRI? Differential diagnosis that every rheumatologist should know - Part II.

In the second part of this review article we will describe the imaging features of non- spondyloarthritis (SpA) pathologies that may mimic sacroiliitis on Magnetic Resonance Imaging (MRI), and that readers should be aware (part 2). Based on the established literature, there is currently an "overcall" of sacroiliitis on MRIs. In this setting, differential diagnoses and their imaging features come into play. In fact, non-SpA related sacroiliac joints (SIJs) pathologies are more commonly found than true sacroiliitis on MRI of the SIJs, even in patients with inflammatory type back pain. An imaging literature review, highlighting "easy-to-use" learning points regarding MRI interpretations in patients with suspected sacroiliitis and/or nonspecific lumbar back pain is presented. This two-part article aims to be a snapshot of the most common inflammatory versus non-inflammatory entities found on SIJs imaging studies in routine practice, while trying to keep this review article simple, educational and above all, practical.

Derivation and external validation of the SHIeLD score for predicting outcome in normotensive pulmonary embolism.

BACKGROUND: Identifying patients with normotensive pulmonary embolism (PE) who may benefit from thrombolysis remains challenging. We sought to develop and validate a score to predict 30-days PE-related mortality and/or rescue thrombolysis. METHODS: We retrospectively assessed 554 patients with normotensive PE. Independent predictors of the studied endpoint were identified from variables available at admission in the emergency department and were used to create a score. The model was validated in 308 patients from a separate hospital. RESULTS: A total of 64 patients died or needed rescue thrombolysis (44 in the derivation cohort). Four independent prognostic factors were identified: Shock index ≥ 1.0 (OR 3.33; 95% CI 1.40-7.93; P = 0.006), HypoxaemIa by the PaO2/FiO2 ratio (OR 0.92 per 10 units; 95% CI 0.88-0.97; P < 0.001), Lactate (OR 1.38 per mmol/L; 95% CI 1.09-1.75; P = 0.008) and cardiovascular Dysfunction (OR 5.67; 95% CI 2.60-12.33; P < 0.001) - SHIeLD score. In the development cohort, event rates for each risk tercile were 0.0%, 2.2%, and 21.6%. In the validation cohort, corresponding rates were 0.0%, 1.9%, and 14.3%. The C-statistic was 0.90 (95% CI 0.86-0.94, P < 0.001) in the derivation cohort and 0.82 (95% CI 0.75-0.89, P < 0.001) in the validation cohort. Decision curve analysis showed that the SHIeLD score is able to accurately identify more true positive cases than the European Society of Cardiology decision criteria. CONCLUSIONS: A risk score to predict 30-days PE-related mortality and/or rescue thrombolysis in patients with normotensive PE was developed and validated. This score may assist physicians in selecting patients for closer monitoring or aggressive treatment strategy.

Magnetic resonance imaging ancillary features used in Liver Imaging Reporting and Data System: An illustrative review.

Hepatocellular carcinoma (HCC) usually develops in the setting of chronic liver disease. In the adequate clinical context, both multiphasic contrast-enhanced CT and magnetic resonance imaging are non-invasive modalities that allow accurate diagnosis and staging of HCC, although the latter demonstrates greater sensitivity and specificity. Imaging criteria for HCC diagnosis rely on hemodynamic features such as hyperenhancement in the arterial phase and washout in the portal or equilibrium phase. However, imaging performance drops considerably for small (< 20 mm) nodules because their tendency to exhibit atypical enhancement patterns. In order to improve accuracy in the diagnosis and staging of HCC, particularly in cases of atypical nodules, ancillary features, i.e., imaging characteristics that modify the likelihood of HCC, have been described and incorporated into clinical reports, especially in Liver Imaging Reporting and Data System. In this paper, ancillary imaging features will be reviewed and illustrated.

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project.

The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts.

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.