824 research outputs found
Landscape Features, Human Disturbance or Prey Availability? What Shapes the Distribution of Large Carnivores in Europe?
Knowledge concerning the relative importance of biotic and abiotic factors associated with the long-term settlement of large carnivores in human-dominated landscapes is important for effective species conservation. However, identifying the major drivers of large carnivore occurrences at a continental scale is challenging as several factors can act in concert to affect large carnivore distributions. Thus, we investigated the relationship between the permanent and sporadic occurrences of large carnivores (brown bear, Eurasian lynx, grey wolf and wolverine) and three groups of predictor variables (i.e., landscape attributes, human disturbance and prey availability) on the continental scale in Europe. Specifically, we used generalized linear models (GLMs) and variation partitioning to estimate the independent and cumulative effects of the three predictor groups on large carnivore occurrences. The explained variance for permanent vs. sporadic occurrence was highest for the wolverine (42.8% and 29.7%), followed by the brown bear (20.5% and 16.4%), Eurasian lynx (15.2% and 11.6%) and grey wolf (15.8% and 6.1%). Landscape attributes, such as forest cover, shrub-land cover, altitude and slope, were positively related to the occurrence of grey wolf, brown bear and Eurasian lynx, whereas human disturbance (human population density, distance to roads and to human settlements) was negatively related to wolverine occurrence. For all species, shared effects between landscape attributes and human disturbance accounted for a considerable portion of the explained variation in both permanent and sporadic occurrence, and landscape attributes were generally more important for explaining permanent than sporadic occurrence, except for the wolverine. Prey availability was marginally associated with the permanent occurrence of the grey wolf but we found no statistical effect of prey availability on the occurrence of the other large carnivores. In conclusion, the sporadic occurrence of large carnivores in Europe is more stochastic and less predictable than their permanent occurrence. Landscape attributes and their joint effects with human disturbance are the most important factors related to the recolonization dynamics of large carnivores, although wolverine distributions appear strongly limited by human disturbance itself. Domestic prey availability seems to play a subordinate role in driving the recent distribution dynamics of large carnivores at the continental scale. Thus, our results are relevant also in light of the ongoing recolonization of large carnivores which, in many rural areas, caused concerns among the locals, especially in relation to conflicts with human activities. For these reasons, we stress the need to continue and improve large carnivore monitoring across Europe
Patterns of distribution and landscape connectivity of the stag beetle in a human-dominated landscape
Urbanisation and the spread of agriculture have resulted in high levels of forest loss, habitat fragmentation and degradation in many regions of the world. In Italy, the Po Plain is the most human-dominated landscape of the country and, after decades of exploitation, old-growth forests have been reduced to small and isolated patches, often threatened by invasive tree species such as the black locust (Robinia pseudoacacia). In these habitats, the occurrence of many forest-dependent species is related to the quality and availability of suitable areas, as well as the connectivity between the remaining forested patches.
Thus, recently developed species distribution models have been applied, namely the Ensemble of Small Models (ESMs), to identify areas of occurrence for a rare and protected saproxylic beetle species, the stag beetle Lucanus cervus and the inverse of the resulting distribution maps as resistance maps have been used to estimate landscape connectivity for this species.
Response curves suggested that the probability of the stag beetle occurrence increased with habitat diversity, grassland coverage and native forests, especially oak and mixed forests. The other forest coverage, such as those with black locust, beech, chestnut and black cherry, showed a unimodal relationship peaking approximately at 70%, 8%, 55% and 13% respectively. The stag beetle occurrence was unimodal related to distance to watercourses and distance to human settlements and negatively related to shrub-lands, croplands, sparse and dense human settlements. Landscape connectivity showed similar patterns, except for oak forest coverage, which showed a negative relationship to landscape connectivity.
In conclusion, stag beetles can persist in a human dominated landscape only in the presence of forest patches, including those with black locust trees. It is also inferred that ESMs may be suitable for modelling rare species distributions and estimating landscape connectivity to promote species conservation
Effects of natural and seminatural elements on the composition and dispersion of carabid beetles inhabiting an agroecosystem in Northern Italy
The natural and seminatural components of agricultural landscapes play a key role in maintaining a high level of biodiversity. Being the Po Valley one of the most human-dominated and intensively cultivated landscapes in Europe, we investigated the effect of no-crop habitats on carabid richness and composition and evaluated the role of tree row as corridor for forest carabid dispersion. Carabids were sampled with 70 pitfall traps arranged in 35 sampling plots along three parallel transects (80, 100, and 140 m long) and encompassing five different habitats: tree row, tree row edge, grassland, forest edge, and forest. We found 5,615 individuals belonging to 55 species. Despite the similarity in species richness, all the habitats investigated showed a peculiar and distinct species assemblage. The main distinction was between the "open habitat" cluster composed of grassland and tree row edge and the âforest" cluster composed of forest, tree row, and forest edge. We found that forest species are able to penetrate the grassland matrix up to 30 m from the forest edge and that a distance of no more than 60 m between tree row and forest can allow the passage of up to 50% of the forest species. Beyond this distance, the grassland matrix becomes a barrier, preventing them from reaching other suitable habitats. Our findings confirm the importance of maintaining different types of natural habitats to significantly increase biodiversity in an intensively cultivated agroecosystem and demonstrated the role of linear elements as a corridor and âstepping stonesâ for many forest species
MOLECULAR BASIS FOR THE DUAL FUNCTION OF EPS8 IN CONTROLLING ACTIN CYTOSKELETON DYNAMICS: BUNDLING AND CAPPING
Actin capping and cross-linking proteins regulate the dynamics and architectures of different cellular protrusions by controlling the number of free actin growing ends and organizing filaments into higher order structures, respectively. Eps8 is the founding member of a unique family of capping proteins capable of side-binding and bundling actin filaments. However, the structural basis through which Eps8 exerts these functions remains elusive.
Here, we combined biochemical, structural and genetic approaches to dissect the molecular mechanism responsible for the distinct Eps8 activities. We show how diverse portions within the C-terminal region of Eps8 contribute to actin binding and mediate Eps8 functions. An N-terminal amphipathic H1 helix, homologous to WH2 domains, is responsible for high affinity interactions with the barbed end unit of filamentous actin and is crucial for the capping activity of the protein. A four helix bundle represents the second interaction surface which mediates contact with the filament side and is crucial for the F-actin bundling activity. Within this context, the two actin binding surfaces are spatially coordinated by a flexible linker that contributes to the high affinity interaction of Eps8 to filaments ends, ensuring a bimodal topological arrangement of Eps8 wrapped around actin filaments. This bimodal way of association to the terminal ends of actin filaments also accounts for the dual modes of organizing F-actin, via capping and cross-linking, respectively. Single-point mutagenesis validated this mode of binding, further permitting us to dissect Eps8 capping from bundling activity in vitro and in vivo. Thus, Eps8 controls actin-based motility through its capping activity, while, as a bundler, is essential for proper intestinal morphogenesis of developing Caernorhabditis elegans strains.
In summary, we provided molecular and structural details of how Eps8 uniquely associates with barbed ends and sides of actin filaments through distinct structural modules. We further showed that the capping and the bundling activities of Eps8 can be fully dissected in vivo, demonstrating the physiological relevance of the identified Eps8 structural/functional module
A Simple Biomimetic Receptor Selectively Recognizing the GlcNAc2 Disaccharide in Water
AbstractGlcNAc2 is the core disaccharide fragment present in Nâglycans exposed on the surface of enveloped viruses of high health concern, such as coronaviruses. Because Nâglycans are directly involved in the docking of viruses to host cells, recognition of GlcNAc2 by a biomimetic receptor may be a convenient alternative to the use of lectins to interfere with viral entry and infection. Herein, we describe a simple biomimetic receptor recognizing the methylâÎČâglycoside of GlcNAc2 in water with an unprecedented affinity of 160â
ÎŒM, exceeding that of more structurally complex receptors reported in the literature. The tweezersâshaped acyclic structure exhibits marked selectivity among structurally related disaccharides, and complete discrimination between monoâ and disaccharides. Molecular modelling calculations supported by NOE data provided a threeâdimensional description of the binding mode, shedding light on the origin of the affinities and selectivities exhibited by the receptor
POS0250â SIGNIFICANT DAMAGE OCCURS EARLY IN THE COURSE OF EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS AND IS MAINLY DUE TO DISEASE-RELATED SEQUELAE
Background:Following the introduction of effective immunosuppressive treatments, ANCA-associated vasculitides (AAV) have become chronic diseases with a remitting-relapsing course. Therefore, preventing chronic damage accrual during follow-up is critical, as relapses, treatment-related side effects, and comorbidities may significantly affect the long-term outcomes of AAV patients. At present, no study specifically evaluated the burden of damage in patients with eosinophilic granulomatosis with polyangiitis (EGPA).Objectives:To describe short-term (6 months) and long-term (5 years) damage accrual in patients with newly diagnosed EGPA.Methods:Patients diagnosed with EGPA, according to ACR criteria and/or Chapel Hill definitions and regularly followed-up in our vasculitis center for â„5 years were included. Damage accrual was assessed with the Vasculitis Damage Index (VDI). Short-term and long-term damage accrual was defined by VDI at 6 months and at 5 years, respectively, and categorized as related to vasculitis or its treatment.Results:VDI data at 6 months were available for 45 EGPA patients: 24 (53.3%) female, mean age at diagnosis 51.6±13.0 years. ANCA were positive in 17 patients (37.8%), with MPO being the only detected enzyme immunoassay (EIA)-specificity. At 6 months mean VDI was 2.8±1.3; 25/45 (55.6%) and 6/45 patients (13.3%) presented â„3 and â„5 items, respectively, whilst only 1 patient (2.2%) showed no items of damage. VDI data at 5 years were available for 32/45 EGPA patients (71.1%): 16 (50%) female, mean age at diagnosis 51.5±13.1 years. MPO-ANCA were positive in 13 patients (40.6%). At 5 years mean VDI was 3.5±1.3, with 26/32 (81.3%) and 7/32 patients (21.9%) presenting â„3 and â„5 items, respectively; notably, no patients presented a VDI=0 at 5 years.The most frequent disease-related VDI items at 6 months and at 5 years were asthma, chronic sinusitis, peripheral neuropathy, cardiomyopathy, pulmonary function tests abnormalities and nasal blockage (Figure 1). Osteoporotic fractures, diabetes and systemic hypertension were the most commonly reported treatment-related items at 6 months and at 5 years (Figure 1). Damage accrual progressively rose during the 5-year follow-up (P=0.023), mainly due to disease-related items rather than treatment-related items both at 6 months (disease related VDI 2.6±1.2, treatment-related VDI 0.3±0.6) and at 5 years (disease related VDI 2.9±1.2, treatment-related VDI 0.6±0,7). No significant difference in terms of damage accrual was observed between ANCA-positive and ANCA-negative patients (P >0.5).Conclusion:In our cohort of EGPA patients damage accrual occurs early, with more than half of the patients displaying â„3 VDI items already at 6 months. Poor control of previous disease activity, particularly ENT and respiratory manifestations, contributes to progressive damage accrual more than treatment side effects.Figure 1.Disease-related and treatment-related VDI items at 6 months and at 5 years in patients with EGPA.Disclosure of Interests:None declare
Effect of phosphate additives on the hydration process of magnesium silicate cements: Thermal and spectroscopic characterization
The role of phosphate additives on the hydration process of magnesium silicate cement pastes was investigated through a multi-technique approach. A MgO/SiO2 mixture was hydrated for 28 days either in the absence or in the presence of sodium hexametaphosphate, trimetaphosphate or orthophosphate. Information on the kinetics of the hydration reaction was acquired by monitoring the free water index by means of differential scanning calorimetry, while the hydration products were thoroughly investigated by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and 29Si solid-state nuclear magnetic resonance spectroscopy. The overall results provide new insight into the effect of phosphates on the hydration reaction and on the structure of magnesium silicate hydrate cements. All additives showed a plasticizing effect and promoted the formation of the binding phase magnesium silicate hydrate (MâSâH), without significantly altering its structure. Sodium orthophosphate was found to be by far the best-performing additive, even better than sodium hexametaphosphate, which is commonly used in these cementitious formulations. For the first time, 31P solid-state NMR investigation allowed orthophosphate ion to be identified as the effective species
Early detection of ventricular dysfunction in juvenile systemic sclerosis by speckle tracking echocardiography
Objective: Cardiac involvement is the most important cause of mortality in juvenile systemic sclerosis (JSSc). Recent reports in adult patients underline that traditional techniques of imaging are inadequate to assess the subclinical cardiac involvement, while speckle tracking echocardiography (STE) is able to identify ventricular dysfunctions in the early stages. The aim of our study was to assess the role of STE in JSSc. Methods: Demographic, clinical and laboratory data were collected from patients with JSSc. Cardiac investigations performed at baseline (T0) and 18 (T18) and 36 months (T36) follow-up included electrocardiography, conventional echocardiography with measurement of the ejection fraction (EF) and STE with assessment of left and right ventricular global longitudinal strain (LV-GLS and RV-GLS). Cardiac parameters have been compared with demographic characteristics and disease severity, assessed by the Juvenile Systemic Sclerosis Severity Score (J4S). Results: A total of 18 patients, 12 (67%) females, entered the study. At T0, electrocardiography was abnormal in three patients, EF was reduced in one, LV-GLS was abnormal in three (16.7%) and RV-GLS was abnormal in five (27.8%). At T18, EF remained stable while at T36 the result decreased in seven of nine patients. At the same time, LV-GLS also worsened (from -21.6% to -18.2%, P = 0.01). LV-GLS and RV-GLS at baseline showed a significant correlation with J4S (P = 0.012 and P = 0.02, respectively). Conclusion: STE is more sensitive than standard echocardiography to identify cardiac involvement in JSSc. Over time, we observed a gradual worsening of LV-GLS, a sign of left ventricular dysfunction, that anticipated by several months the decrease of EF
Detection and whole genome sequencing of CPMMV in common bean resistant to BGMV from ParanĂĄ State.
Cowpea mild mottle virus (CPMMV) is a Carlavirus from the family Betaflexiviridae which has a linear single stranded positive sense rna genome of approximately 8,200 nt and infects a wide range of cultivated plants from the Fabaceae family. It is transmitted by the whitefly Bemisia tabaci
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