The Genome of the Diatom Thalassiosira Pseudonana: Ecology, Evolution and Metabolism

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for {approx}20% of global carbon fixation. We report the 34 Mbp draft nuclear genome of the marine diatom, Thalassiosira pseudonana and its 129 Kbp plastid and 44 Kbp mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, utilization of a range of nitrogenous compounds and a complete urea cycle, all attributes that allow diatoms to prosper in the marine environment. Diatoms are unicellular, photosynthetic, eukaryotic algae found throughout the world's oceans and freshwater systems. They form the base of short, energetically-efficient food webs that support large-scale coastal fisheries. Photosynthesis by marine diatoms generates as much as 40% of the 45-50 billion tonnes of organic carbon produced each year in the sea (1), and their role in global carbon cycling is predicted to be comparable to that of all terrestrial rainforests combined (2, 3). Over geological time, diatoms may have influenced global climate by changing the flux of atmospheric carbon dioxide into the oceans (4). A defining feature of diatoms is their ornately patterned silicified cell wall or frustule, which displays species-specific nano-structures of such fine detail that diatoms have long been used to test the resolution of optical microscopes. Recent attention has focused on biosynthesis of these nano-structures as a paradigm for future silica nanotechnology (5). The long history (over 180 million years) and dominance of diatoms in the oceans is reflected by their contributions to vast deposits of diatomite, most cherts and a significant fraction of current petroleum reserves (6). As photosynthetic heterokonts, diatoms reflect a fundamentally different evolutionary history from the higher plants that dominate photosynthesis on land. Higher plants and green, red and glaucophyte algae are derived from a primary endosymbiotic event in which a non-photosynthetic eukaryote acquired a chloroplast by engulfing (or being invaded by) a prokaryotic cyanobacterium. In contrast, dominant bloom-forming eukaryotic phytoplankton in the ocean, such as diatoms and haptophytes, were derived by secondary endosymbiosis whereby a non-photosynthetic eukaryote acquired a chloroplast by engulfing a photosynthetic eukaryote, probably a red algal endosymbiont (Fig. 1). Each endosymbiotic event led to new combinations of genes derived from the hosts and endosymbionts (7). Prior to this project, relatively few diatom genes had been sequenced, few chromosome numbers were known, and genetic maps did not exist (8). The ecological and evolutionary importance of diatoms motivated our sequencing and analysis of the nuclear, plastid, and mitochondrial genomes of the marine centric diatom Thalassiosira pseudonana

Systemic lupus erythematosus associated with vasculitic syndrome (Takayasu's arteritis)

A 43-year-old woman reported pain in the right hypochondrium, which had started 3 years before and had been worsening for the past few days. Claudication in the superior and inferior limbs, diffuse myalgia, dyspnea, precordialgia followed by dizziness and visual turbidity were added to the clinical picture. In the physical examination bilateral carotid bruit was observed, abdominal aorta murmur and the decrease of the right radial and left pedis pulses and arterial hypertension with difference in the diastolic pressure between limbs > 10 mmHg was also observed. On cardiac catheterisation with aortography, right coronary with proximal parietal irregularities, slight pressure increase in right chambers and pulmonary artery, preserved left ventricle contractility, competent valves, carotid and subclavian partial obstruction, severe narrowing of the abdominal aorta below the diaphragm (80%) and right renal artery significant stenosis were observed. Takayasu's arteritis (TA) diagnosis was established according to the ACR criteria based on the clinical symptomatology, on physical and image test findings. Two years later she presented malar rash, photosensitivity, nephropathy, leukopenia, lymphopenia and hemolytic anemia confirming the systemic lupus erythematosus (SLE) diagnosis. TA coexisting with SLE has rarely been reported.30121669167

HLA Markers for Poor Prognosis in Systemic Sclerosis Brazilian Patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Objectives. The aim of this study was to evaluate human leukocyte antigen (HLA) involvement in the disease expression and poor prognostic clinical features (pulmonary fibrosis and pulmonary arterial hypertension) in patients diagnosed with systemic sclerosis (SSc) in a multiethnic population. Methods. SSc patients followed up between 2008 and 2011 were included, and clinical data were obtained through records review. Molecular HLA typing was performed (polymerase chain reaction amplification technique using specific primer sequences). The statistical analysis involved Fisher's exact test and Pearson's corrected chi-square test. P values < 0.05 were considered significant. The delta method was used to estimate the variance of the prevalence ratio (PR). Results. A total of 141 patients (120 women and 21 men) with SSc were studied, including 33.3% with diffuse cutaneous SSc (dcSSc), 62.4% with limited cutaneous SSc (lcSSc), and 4.3% with sine scleroderma. Pulmonary fibrosis was present in 61 patients (43.3%), and the HLA-A*30 and DQB1*04 alleles were related to susceptibility. In contrast, the HLA-DRB1*01 and DQB1*05 alleles were protective. Pulmonary arterial hypertension was diagnosed in 19 patients (13.5%) and was associated with HLA-B*35 and C*04; in contrast, C*03 seemed to be protective. Conclusions. Our current study documents the association of some classes I and II HLA alleles with the most severe clinical manifestations in a multiethnic case series. Our findings differed slightly from the previous data in other populations.7378Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2008/58010-3

Systemic sclerosis sine scleroderma: distinct features in a large Brazilian cohort

Objective. Systemic sclerosis sine scleroderma (ssSSc) is an infrequent SSc variant characterized by visceral and immunological manifestations of SSc in the absence of clinically detectable skin involvement. We sought to delineate the characteristics of ssSSc in a cohort of Brazilian patients and contrast them with those in the literature. Methods. SSc patients seen at two academic medical centres in Brazil were retrospectively analysed. Patients were classified as ssSSc if they presented with RP, positive ANAs and at least one visceral involvement typical of SSc in the absence of skin thickening. Demographics, clinical and laboratory data were obtained by chart review. Literature review was performed by searching available original studies up until June 2012. Results. Among the 947 consecutive patients with SSc, 79 (8.3%) were classified as ssSSc. Oesophagus was the most frequently affected organ (83.1%), followed by pulmonary involvement (63.2%). Compared with the limited cutaneous form of SSc, telangiectasia was the only variable significantly different after multivariate logistic regression analyses (odds ratio 0.46; 95% CI 0.27, 0.81). Compared with the diffuse cutaneous form of SSc, multivariate analyses revealed that ssSSc patients were less likely to be male (odds ratio 0.15; 95% CI 0.04, 0.57), have digital ulcers (odds ratio 0.26; 95% CI 0.13, 0.51) or anti-Scl70 antibodies (odds ratio 0.19; 95% CI 0.07, 0.55) and less frequently treated with CYC (odds ratio 0.23; 95% CI 0.12, 0.43). These features were comparable to those in the published literature. Conclusion. In this series, patients with ssSSc had a relatively mild disease with good prognosis.52815201524Federico Foundatio