45 research outputs found

    The Mediterranean Island Wetlands (MedIsWet) inventory: strengths and shortfalls of the currently available floristic data

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    MedIsWet (Conservation of the island wetlands of the Mediterranean Basin) is a MAVA funded project which aims at investigating all seasonal or permanent island wetlands both natural and artificial, with a minimum extent of 0.1 hectares. More than 16,000 wetlands from almost all the Mediterranean, including islands from France, Italy, Malta, Croatia, Cyprus, Tunisia, Turkey, Greece and Spain were mapped. Over 2,500 of them were inventoried in the field and more than 500 scientific contributions catalogued. In total, more than 35,000 plant occurrences were uploaded, in a standardised and comparable way, on the national open-source web portals. These can be related to the recorded threats, uses and other spatially retrievable information. Here, we show strengths and shortfalls of the already available information about the floristic records. Although further improvements are needed, we discuss how these data can be used for research and policy actions and to develop conservation projects

    The expanding functional roles and signaling mechanisms of adhesion G protein–coupled receptors

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    The adhesion class of G protein–coupled receptors (GPCRs) is the second largest family of GPCRs (33 members in humans). Adhesion GPCRs (aGPCRs) are defined by a large extracellular N‐terminal region that is linked to a C‐terminal seven transmembrane (7TM) domain via a GPCR‐autoproteolysis inducing (GAIN) domain containing a GPCR proteolytic site (GPS). Most aGPCRs undergo autoproteolysis at the GPS motif, but the cleaved fragments stay closely associated, with the N‐terminal fragment (NTF) bound to the 7TM of the C‐terminal fragment (CTF). The NTFs of most aGPCRs contain domains known to be involved in cell–cell adhesion, while the CTFs are involved in classical G protein signaling, as well as other intracellular signaling. In this workshop report, we review the most recent findings on the biology, signaling mechanisms, and physiological functions of aGPCRs

    A split horseradish peroxidase for detection of intercellular protein-protein interactions and sensitive visualization of synapses

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    Intercellular protein-protein interactions (PPIs) enable communication between cells in diverse biological processes, including cell proliferation, immune responses, infection and synaptic transmission, but they are challenging to visualize because existing techniques1,2,3 have insufficient sensitivity and/or specificity. Here we report split horseradish peroxidase (sHRP) as a sensitive and specific tool for detection of intercellular PPIs. The two sHRP fragments, engineered through screening of 17 cut sites in HRP followed by directed evolution, reconstitute into an active form when driven together by an intercellular PPI, producing bright fluorescence or contrast for electron microscopy. Fusing the sHRP fragments to the proteins neurexin (NRX) and neuroligin (NLG), which bind each other across the synaptic cleft4, enabled sensitive visualization of synapses between specific sets of neurons, including two classes of synapses in the mouse visual system. sHRP should be widely applicable for studying mechanisms of communication between a variety of cell types

    Bone bruises detected by magnetic resonance imaging following lateral ankle sprains.

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    Although bone bruises have been well described in the knee joint, little is known about their presence in the ankle joint. The present study attempted to document the association of bone bruises with lateral ankle sprains. Magnetic resonance (MR) images were obtained from 60 consecutive patients with lateral ankle sprains between April 1994 and June 1995. There were 29 men and 31 women, aged on average 25 years (range 12-68 years). All of the patients presented within 3 weeks of the sprain. MRI examinations were done within 3 weeks of the injury in 15, after 3-6 weeks in 21, and after 6-8 weeks in 24 cases. There were 28 first-time sprains, while 32 patients had suffered one or more sprains before the most recent one. Plain radiographs showed no evidence of osseous abnormality. Following the conventional MRI examination, magnetic resonance arthrography (MRA) was done by injecting 2 mM of gadolinium diethylene triamine penta-acetic acid (DTPA) into the joint under fluoroscopic control, and the same images were obtained again to search for ligamentous lesions. A total of 11 bone bruises were detected in 10 ankles. In this group of patients, there were 5 men and 5 women aged on average 27 years (range 12-50 years). Four MRI examinations were done within 3 weeks, while six were done 3-6 weeks after the injury. One ankle which had suffered one previous sprain and complete ruptures of anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) had two lesions (talus and navicula). In another recurrent case with complete ATFL and CFL ruptures, the lesion was found in the calcaneus. The remaining eight lesions were in the talus in eight ankles. The ligamentous lesions in these ankles included three complete ATFL and CFL ruptures, and four isolated ATFL ruptures; in one ankle there were no ligamentous lesions. The location of talar bruises was medial in six and lateral in three ankles. The incidence of bone bruises associated with isolated ATFL lesions was 16% (4/25). With combined ATFL and CFL lesions the incidence was 50% (5/10). The incidence of ankles with bone bruises and first-time and recurrent sprains was 7% (2/28) and 25% (8/32), respectively. The occurrence of bone bruises should be kept in mind following ankle sprains. Their clinical significance in the long term remains to be determined

    Phosphatidylinositol 4,5-bisphosphate clusters act as molecular beacons for vesicle recruitment.

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    Synaptic-vesicle exocytosis is mediated by the vesicular Ca(2+) sensor synaptotagmin-1. Synaptotagmin-1 interacts with the SNARE protein syntaxin-1A and acidic phospholipids such as phosphatidylinositol 4,5-bisphosphate (PIP2). However, it is unclear how these interactions contribute to triggering membrane fusion. Using PC12 cells from Rattus norvegicus and artificial supported bilayers, we show that synaptotagmin-1 interacts with the polybasic linker region of syntaxin-1A independent of Ca(2+) through PIP2. This interaction allows both Ca(2+)-binding sites of synaptotagmin-1 to bind to phosphatidylserine in the vesicle membrane upon Ca(2+) triggering. We determined the crystal structure of the C2B domain of synaptotagmin-1 bound to phosphoserine, allowing development of a high-resolution model of synaptotagmin bridging two different membranes. Our results suggest that PIP2 clusters organized by syntaxin-1 act as molecular beacons for vesicle docking, with the subsequent Ca(2+) influx bringing the vesicle membrane close enough for membrane fusion

    Structural Basis for Regulation of GPR56/ADGRG1 by Its Alternatively Spliced Extracellular Domains

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    Adhesion G-protein-coupled receptors (aGPCRs) play critical roles in diverse neurobiological processes including brain development, synaptogenesis, and myelination. aGPCRs have large alternatively spliced extracellular regions (ECRs) that likely mediate intercellular signaling; however, the precise roles of ECRs remain unclear. The aGPCR GPR56/ADGRG1 regulates both oligodendrocyte and cortical development. Accordingly, human GPR56 mutations cause myelination defects and brain malformations. Here, we determined the crystal structure of the GPR56 ECR, the first structure of any complete aGPCR ECR, in complex with an inverse-agonist monobody, revealing a GPCR-Autoproteolysis-Inducing domain and a previously unidentified domain that we term Pentraxin/Laminin/neurexin/sex-hormone-binding-globulin-Like (PLL). Strikingly, PLL domain deletion caused increased signaling and characterizes a GPR56 splice variant. Finally, we show that an evolutionarily conserved residue in the PLL domain is critical for oligodendrocyte development in vivo. Thus, our results suggest that the GPR56 ECR has unique and multifaceted regulatory functions, providing novel insights into aGPCR roles in neurobiology
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