Haplo-diplontic life cycle expands coccolithophore niche

Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo- diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases and potentially expands coccolithophore niche volume. Research has, however, to date largely overlooked the life cycle of coccolithophores and has instead focused on the diploid life cycle phase of coccolithophores. Through the synthesis and analysis of global scanning electron microscopy (SEM) coccolithophore abundance data (n=2534), we find that calcified haploid coccolithophores generally constitute a minor component of the total coccolithophore abundance (≈ 2 %–15 % depending on season). However, using case studies in the Atlantic Ocean and Mediterranean Sea, we show that, depending on environmental conditions, calcifying haploid coccolithophores can be significant contributors to the coccolithophore standing stock (up to ≈30 %). Furthermore, using hypervolumes to quantify the niche of coccolithophores, we illustrate that the haploid and diploid life cycle phases inhabit contrasting niches and that on average this allows coccolithophores to expand their niche by ≈18.8 %, with a range of 3 %–76 % for individual species. Our results highlight that future coccolithophore research should consider both life cycle stages, as omission of the haploid life cycle phase in current research limits our understanding of coccolithophore ecology. Our results furthermore suggest a different response to nutrient limitation and stratification, which may be of relevance for further climate scenarios. Our compilation highlights the spatial and temporal sparsity of SEM measurements and the need for new molecular techniques to identify uncalcified haploid coccolithophores. Our work also emphasizes the need for further work on the carbonate chemistry niche of the coccolithophore life cycle

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

A murine model of cerebral cavernous malformations with acute hemorrhage

Cavernomas are multi-lumen and blood-filled vascular malformations which form in the brain and the spinal cord. They lead to hemorrhage, epileptic seizures, neurological defi zits, and paresthesia. An effective medical treatment is still lacking, and the available murine models for cavernomas have several limitations for predinical studies. These include disease phenotypes that differ from human diseases, such as restriction of the lesions to the cerebellum, and absence of acute hemorrhage. Additional limitations of current murine models include rapid development of lesions, which are lethal before the first month of age. Here, we have characterized a murine model that recapitulates features of the human disease: lesions develop after weaning throughout the entire CNS, including the spinal cord, and undergo acute hemorrhage. This provides a preclinical model to develop new drugs for treatment of acute hemorrhage in the brain and spinal cord, as an unmet medical emergency for patients with cavernomas

Coccolithophore combination coccospheres from the NE Mediterranean Sea: new evidence and taxonomic revisions

Numerous specimens of coccolithophore combination coccospheres in water samples collected from the North Aegean and Tyrrhenian (Mediterranean Sea) have been photographed using the scanning electron microscope.As a consequence a series of taxonomic revisions are proposed, in which the names of the heterococcolithophores and holococcolithophores involved in the same life-cycle are synonymized. This has resulted in synonymizing the genus Coronosphaera with Syracosphaera and establishing one new combination; Syracosphaera arethusae (Kamptner 1941) comb. nov

Primary Sclerosing Cholangitis: Burden of Disease and Mortality Using Data from the National Rare Diseases Registry in Italy

Introduction: Studies on the epidemiology of primary sclerosing cholangitis (PSC) are mainly based on tertiary referral centers; and are retrospective case series susceptible to selection bias. The aim of this study was to estimate incidence; survival and cause of mortality of PSC in Italy; using population-based data. Methods: Data collected from the National Rare Diseases Registry (RNMR) and the National Mortality Database (NMD) were integrated and analyzed. Results: We identified 502 PSC incident cases. The crude incidence rate between 2012 and 2014 was 0.10 per 100,000 individuals. Sixty percent were male; mean age at disease onset and at diagnosis were 33 and 37 years; respectively; highlighting a mean diagnostic delay of 4 years. The rate of interregional mobility was 12%. Ten-year survival was 92%. In 32% of cases the cause of death was biliary-related; 12% died of biliary or gallbladder cancer. Conclusions: For rare diseases such as PSC; population-based cohort&rsquo;s studies are of paramount importance. Incidence rates of PSC in Italy are markedly lower and survival much longer than the ones reported from tertiary; single-centre series. Moreover; the diagnostic delay and the patient interregional mobility highlights the need for increasing awareness on the disease and for resource reallocation among Italian regions within the National Health Servic

Comprehensive review of autoantibodies in patients with hyper-IgM syndrome

International audienceHyper-immunoglobulin M syndrome is an X-linked primary immunodeficiency disease caused by mutations in the CD40 ligand gene. The CD40 ligand has been recently highlighted as playing a key role in the pathogenesis of primary biliary cholangitis. In the present study, we assessed an extensive set of serum autoantibodies in a series of well-defined patients with hyper-immunoglobulin M syndrome. Serum, liver-related and liver-not-related autoantibodies IgG, IgM and IgA were tested by ELISA and standard indirect immunofluorescence in HEp-2 cells in 13 Tunisian patients (8 males and 5 females, aged 1-12 years) with hyper-immunoglobulin M syndrome during 1995-2012 and, as controls, 21 age-and gender-matched blood donors. The level of IgM antibody against MIT3 was significantly higher in patients than in controls (35.8 vs 10.7, P = 0.002). Half of the hyperimmunoglobulin M syndrome patients were found to be anti-MIT3 IgM positive vs none of the controls (Po0.0001). Twenty-three percent of patients were found to be anti-sp100 antibody positive vs only 0.05% of controls. By immunofluorescence, 92.3% of patients were MIT3 IgM positive vs none of the controls. In conclusion, the IgM class of anti-MIT3 antibodies was shown to be present by both ELISA and immunofluorescence in most of the patients with hyper-immunoglobulin M syndrome. The presence of the hallmark of primary biliary cholangitis, a disease where the CD40 ligand is a key player, in an immunodeficiency disease caused by mutations in the CD40 ligand gene is very intriguing and opens new scenarios in understanding the immune pathogenesis of primary biliary cholangitis

Endothelial cell clonal expansion in the development of cerebral cavernous malformations

Cerebral cavernous malformation (CCM) is a neurovascular familial or sporadic disease that is characterised by capillary-venous cavernomas, and is due to loss-of-function mutations to any one of three CCM genes. Familial CCM follows a two-hit mechanism similar to that of tumour suppressor genes, while in sporadic cavernomas only a small fraction of endothelial cells shows mutated CCM genes. We reported that in mouse models and in human patients, endothelial cells lining the lesions have different features from the surrounding endothelium, as they express mesenchymal/stem-cell markers. Here we show that cavernomas originate from clonal expansion of few Ccm3-null endothelial cells that express mesenchymal/stem-cell markers. These cells then attract surrounding wild-type endothelial cells, inducing them to express mesenchymal/stem-cell markers and to contribute to cavernoma growth. These characteristics of Ccm3-null cells are reminiscent of the tumour-initiating cells that are responsible for tumour growth. Our data support the concept that CCM has benign tumour characteristics