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Multiple complex biological processes take place during pregnancy, including the migration of fetal cells to maternal circulation and their subsequent engraftment in maternal tissues, where they form microchimerisms. Fetal microchimerisms have been identified in several tissues; nevertheless, their functional role remains largely unknown. Different reports suggest these cells contribute to tissue repair and modulate the immune response, but they have also been associated with pre-eclampsia and tumor formation. In the maternal heart, cells of fetal origin can contribute to different cell lineages after myocardial infarction. However, the functional role of these cells and their effect on cardiac function and repair are unknown. In this work, we found that microchimerisms of fetal origin are present in the maternal circulation and graft in the heart. To determine their functional role, WT female mice were crossed with male mice expressing the diphtheria toxin (DT) receptor. Mothers were treated with DT to eliminate microchimerisms and the response to myocardial infarction was investigated. We found that removal of microchimerisms improved cardiac contraction in postpartum and post-infarction model females compared to untreated mice, where DT administration had no significant effects. These results suggest that microchimerisms play a detrimental role in the mother following myocardial infarction.

Despite the plasma proteome being able to provide a unique insight into the health and disease status of individuals, holding singular promise as a source of protein biomarkers that could be pivotal in the context of personalized medicine, only around 100 proteins covering a few human conditions have been approved as biomarkers by the US Food and Drug Administration (FDA) so far. Mass spectrometry (MS) currently has enormous potential for high-throughput analysis in clinical research; however, plasma proteomics remains challenging mainly due to the wide dynamic range of plasma protein abundances and the time-consuming procedures required. We applied a new MS-based multiplexed proteomics workflow to quantitate proteins, encompassing 67 FDA-approved biomarkers, in >1300 human plasma samples from a clinical cohort. Our results indicate that this workflow is suitable for large-scale clinical studies, showing good accuracy and reproducibility (coefficient of variation (CV) < 20 for 90% of the proteins). Furthermore, we identified plasma signature proteins (stable in time on an individual basis), stable proteins (exhibiting low biological variability and high temporal stability), and highly variable proteins (with low temporal stability) that can be used for personalized health monitoring and medicine.

Prevailing social, economic and political ideas and paradigms constitute the lens through which scientists observe, assess, and understand the world. This affects how we interpret and understand the mechanisms governing the interaction between organisms and has led, in most cases, to dominant explanations and paradigms that are difficult to overthrow. This is the case of ecological theory, whose perspectives have followed the rationale of societal changes. From the industrial revolution to very recently, species competition for resources was regarded as one of the main drivers of species interactions. Nowadays, a new and rapidly growing way of thinking emerged, fueled by the high sequencing capacities, ultra-resolution microscopy and the slowly growing number of different social and gender perspectives participating in ecological studies: that living beings are not just single organisms interacting with other single organisms, but complex communities of macro- and microorganisms living and evolving together. The information emerging from this field is bringing new light to previously disregarded aspects of the ecological interactions that, in our opinion, will change the main paradigms in ecology. As members of a South American scientific network of Aquatic Microbial Ecology (MicroSudAqua), here we propose to explore alternative explanations for ecological observations, searching for new traits accounting for cooperation between microorganisms as a fundamental evolutionary and ecological strategy. * Photo: Hyalosphenia papilio (Amoebozoa; Arcellinida), an amoeba species that hosts endosymbiotic algae related to the genus Chlorella. These organisms live in boreal peat bogs, an oligotrophic environment where they obtain much needed nutrients through their photosynthesizing partners. The amoeba requires the alga to close its life cycle, and has never been observed without it. Image: Prof. Edward A. D. Mitchell

Introduction: Removal of poorly perfused capillaries by pruning contributes to remodeling the microvasculature to optimize oxygen and nutrient delivery. Blood flow drives this process by promoting the intravascular migration of endothelial cells in developing networks, such as in the yolk sac, zebrafish brain or postnatal mouse retina.Methods: In this study, we have implemented innovative tools to recognize capillary pruning in the complex 3D coronary microvasculature of the postnatal mouse heart. We have also experimentally tested the impact of decreasing pruning on the structure and function of this network by altering blood flow with two different vasodilators: losartan and prazosin.Results: Although both drugs reduced capillary pruning, a combination of experiments based on ex vivo imaging, proteomics, electron microscopy and in vivo functional approaches showed that losartan treatment resulted in an inefficient coronary network, reduced myocardial oxygenation and metabolic changes that delayed the arrest of cardiomyocyte proliferation, in contrast to the effects of prazosin, probably due to its concomitant promotion of capillary expansion.Discussion: Our work demonstrates that capillary pruning contributes to proper maturation and function of the heart and that manipulation of blood flow may be a novel strategy to refine the microvasculature and improve tissue perfusion after damage.

Abstract Background Heart failure (HF) with preserved ejection fraction (HFpEF) prevalence is increasing, and large clinical trials have failed to reduce mortality. A major reason for this outcome is the failure to translate results from basic research to the clinics. Evaluation of HFpEF in mouse models requires assessing three major key features defining this complex syndrome: the presence of a preserved left ventricular ejection fraction (LVEF), diastolic dysfunction, and the development of HF. In addition, HFpEF is associated with multiple comorbidities such as systemic arterial hypertension, chronic obstructive pulmonary disease, sleep apnea, diabetes, and obesity; thus, non-cardiac disorders assessment is crucial for a complete phenotype characterization. Non-invasive procedures present unquestionable advantages to maintain animal welfare and enable longitudinal analyses. However, unequivocally determining the presence of HFpEF using these methods remains challenging. Main text Transthoracic echocardiography (TTE) represents an invaluable tool in HFpEF diagnosis, allowing evaluation of LVEF, diastolic dysfunction, and lung congestion in mice. Since conventional parameters used to evaluate an abnormal diastole like E/A ratio, isovolumic relaxation time, and E/e′ may pose limitations in mice, including advanced TTE techniques to characterize cardiac motion, including an assessment under stress, will improve diagnosis. Patients with HFpEF also show electrical cardiac remodelling and therefore electrocardiography may add valuable information in mouse models to assess chronotropic incompetence and sinoatrial node dysfunction, which are major contributors to exercise intolerance. To complete the non-invasive diagnosis of HF, low aerobic exercise capacity and fatigue using exercise tests, impaired oxygen exchange using metabolic cages, and determination of blood biomarkers can be determined. Finally, since HFpEF patients commonly present non-cardiac pathological conditions, acquisition of systemic and pulmonary arterial pressures, blood glucose levels, and performing glucose tolerance and insulin resistance tests are required for a complete phenotyping. Conclusion Identification of reliable models of HFpEF in mice by using proper diagnosis tools is necessary to translate basic research results to the clinics. Determining the presence of several HFpEF indicators and a higher number of abnormal parameters will lead to more reliable evidence of HFpEF.

Abstract Heart diseases are associated with changes in the biomechanical properties of the myocardial wall. However, there is no modality available to assess myocardial stiffness directly. Brillouin microspectroscopy (mBS) is a consolidated mechanical characterization technique, applied to the study of the viscoelastic and elastic behavior of biological samples and may be a valuable tool for assessing the viscoelastic properties of the cardiac tissue. In this work, viscosity and elasticity were assessed using mBS in heart samples obtained from healthy and unhealthy mice (n = 6 per group). Speckle-tracking echocardiography (STE) was performed to evaluate heart deformation. We found that mBS was able to detect changes in stiffness in the ventricles in healthy myocardium. The right ventricle showed reduced stiffness, in agreement with its increased compliance. mBS measurements correlated strongly with STE data, highlighting the association between displacement and stiffness in myocardial regions. This correlation was lost in pathological conditions studied. The scar region in the infarcted heart presented changes in stiffness when compared to the rest of the heart, and the hypertrophied left ventricle showed increased stiffness following aortic stenosis, compared to the right ventricle. We demonstrate that mBS can be applied to determine myocardial stiffness, that measurements correlate with functional parameters and that they change with disease.

Rain-fed mountain granite rock basins are temporary habitats conditioned by a fluctuating environment and the unpredictability of precipitation or flooding rates. These small highland freshwater habitats remain largely unexplored at the microbial level. The aim of this work is to report the presence in these habitats of genetic sequences of microbial eukaryotes that are pathogens and potential pathogens of humans, wildlife, cattle, crops as well as of other microorganisms. We sequenced the hypervariable region v4 of the 18S rDNA gene from environmental DNA of sediments taken from 21 rock basins in a National Park in Spain. More than a fifth (21%) of the eukaryotic Operational Taxonomic Units (OTUs) found are ascribed to pathogenic (within 11 Phyla) and potential pathogenic (within 1 phylum, the Chytridiomycota) microorganisms. Some OTUs retrieved are of agro-economic and public health importance (e.g., Pythium spp., Lagenidium spp., Candida spp. and Vermamoeba vermiformis). In 86% of the basins, the most abundant OTUs were affiliated to Chytridiomycota, a broad fungal group including saprozoic and parasitic taxa. Two OTUs affiliated to chytrids were significantly correlated with high concentrations of heavy metals. The high proportion of chytrid-like microbial sequences found emphasises the role of these freshwater habitats for adding knowledge regarding the ecological trade-offs of the still rather unknown Chytridiomycota. Our results show that rain-fed rock basins may be model habitats for the study and surveillance of microbial community dynamics and genetics of (mainly opportunistic) microbial pathogens.

Summary: Background: Imaging of subclinical atherosclerosis improves cardiovascular risk prediction on top of traditional risk factors. However, cardiovascular imaging is not universally available. This work aims to identify circulating proteins that could predict subclinical atherosclerosis. Methods: Hypothesis-free proteomics was used to analyze plasma from 444 subjects from PESA cohort study (222 with extensive atherosclerosis on imaging, and 222 matched controls) at two timepoints (three years apart) for discovery, and from 350 subjects from AWHS cohort study (175 subjects with extensive atherosclerosis on imaging and 175 matched controls) for external validation. A selected three-protein panel was further validated by immunoturbidimetry in the AWHS population and in 2999 subjects from ILERVAS cohort study. Findings: PIGR, IGHA2, APOA, HPT and HEP2 were associated with subclinical atherosclerosis independently from traditional risk factors at both timepoints in the discovery and validation cohorts. Multivariate analysis rendered a potential three-protein biomarker panel, including IGHA2, APOA and HPT. Immunoturbidimetry confirmed the independent associations of these three proteins with subclinical atherosclerosis in AWHS and ILERVAS. A machine-learning model with these three proteins was able to predict subclinical atherosclerosis in ILERVAS (AUC [95%CI]:0.73 [0.70–0.74], p

Pathological cardiac fibrosis is a hallmark of diseases leading to heart failure. Here, the authors used systems genetics to identify a pro-fibrotic gene network regulated by WWP2, a E3 ubiquitin ligase, which orchestrates the nucleocytoplasmic shuttling and transcriptional activity of SMAD2 in the diseased heart.

Protists dominate eukaryotic diversity and play key functional roles in all ecosystems, particularly by catalyzing carbon and nutrient cycling. To date, however, a comparative analysis of their taxonomic and functional diversity that compares the major ecosystems on Earth (soil, freshwater and marine systems) is missing. Here, we present a comparison of protist diversity based on standardized high throughput 18S rRNA gene sequencing of soil, freshwater and marine environmental DNA. Soil and freshwater protist communities were more similar to each other than to marine protist communities, with virtually no overlap of Operational Taxonomic Units (OTUs) between terrestrial and marine habitats. Soil protists showed higher γ diversity than aquatic samples. Differences in taxonomic composition of the communities led to changes in a functional diversity among ecosystems, as expressed in relative abundance of consumers, phototrophs and parasites. Phototrophs (eukaryotic algae) dominated freshwater systems (49% of the sequences) and consumers soil and marine ecosystems (59% and 48%, respectively). The individual functional groups were composed of ecosystem- specific taxonomic groups. Parasites were equally common in all ecosystems, yet, terrestrial systems hosted more OTUs assigned to parasites of macro-organisms while aquatic systems contained mostly microbial parasitoids. Together, we show biogeographic patterns of protist diversity across major ecosystems on Earth, preparing the way for more focused studies that will help understanding the multiple roles of protists in the biosphere.

Soils host most biodiversity on Earth, with a major fraction of its taxonomic diversity still to be uncovered and most of its functional knowledge to be determined. Much focus has been - and still is - on bacteria, fungi and animals. Clearly, without any of those components, soils would not function as they do. However, the group that constitutes the bulk of eukaryotic diversity and plays a central role for soil functioning is missing: protists. As the main consumers of the microbiome, protists shape its composition and functioning. Other less known functions performed by protists may be equally important. Protists also include primary producers, decomposers, animal parasites and plant pathogens. We briefly review the many functions protists perform in soils and argue that soil biodiversity studies that ignore protists miss some potential mechanistic insight into the drivers of observed patterns. We highlight that the immense functional repertoire of protist affects virtually every soil process, from carbon cycling to primary production, including crop production. Therefore, we call for truly integrated biodiversity assessments including protists, without which the soil food-web and processes cannot reliably be understood: protists matter!

This review provides a synthesis of current knowledge on the morphological and functional traits of testate amoebae, a polyphyletic group of protists commonly used as proxies of past hydrological changes in paleoecological investigations from peatland, lake sediment and soil archives. A trait-based approach to understanding testate amoebae ecology and paleoecology has gained in popularity in recent years, with research showing that morphological characteristics provide complementary information to the commonly used environmental inferences based on testate amoeba (morpho-)species data. We provide a broad overview of testate amoeba morphological and functional traits and trait-environment relationships in the context of ecology, evolution, genetics, biogeography, and paleoecology. As examples we report upon previous ecological and paleoecological studies that used trait-based approaches, and describe key testate amoebae traits that can be used to improve the interpretation of environmental studies. We also highlight knowledge gaps and speculate on potential future directions for the application of trait-based approaches in testate amoeba research.

Current projections suggest that climate warming will be accompanied by more frequent and severe drought events. Peatlands store ca. one third of the world’s soil organic carbon. Warming and drought may cause peatlands to become carbon sources through stimulation of microbial activity increasing ecosystem respiration, with positive feedback effect on global warming. Micro-eukaryotes play a key role in the carbon cycle through food web interactions and therefore, alterations in their community structure and diversity may affect ecosystem functioning and could reflect these changes. We assessed the diversity and community composition of Sphagnum-associated eukaryotic microorganisms inhabiting peatlands and their response to experimental drought and warming using high throughput sequencing of environmental DNA. Under drier conditions, micro-eukaryotic diversity decreased, the relative abundance of autotrophs increased and that of osmotrophs (including Fungi and Peronosporomycetes) decreased. Furthermore, we identified climate change indicators that could be used as early indicators of change in peatland microbial communities and ecosystem functioning. The changes we observed indicate a shift towards a more “terrestrial” community in response to drought, in line with observed changes in the functioning of the ecosystem.

Introduction: Improved outcome and longer life expectancy in patients with cystinosis and the intrinsic complexity of the disease, underline the need for a guided transition of patients from pediatric to adult care. The process aims to guarantee the continuum of care and enable the empowerment of patients from guardian to self-care. Methods: Bibliography review, expert opinion and anonymous surveys of patients, relatives and patient advocacy groups. Results: A new plan to support and coordinate the transition of cystinotic patients providing specific proposals for a variety of medical fields and improved treatment adherence. Nephrologists play a key role in the transition since most cystinotic patients have severe chronic kidney disease and require kidney transplantation before adulthood. Conclusion: We present a proposal providing recommendations and a chronogram to aid the transition of adolescents and young adults with cystinosis in our area.

Introducción: El aumento de la supervivencia de los pacientes con cistinosis y la propia complejidad de la enfermedad explican la necesidad de implementar un proceso de transición guiada desde la medicina pediátrica hasta la del adulto, que permita garantizar el continuum asistencial y posibilite el empoderamiento del paciente desde el cuidado tutelado al autocuidado. Métodos: Revisión bibliográfica, opinión de expertos, encuestas anónimas a pacientes, familiares y asociaciones. Resultados: Elaboración de un documento de transición coordinada, con propuestas concretas por especialidades y de mejora de la adherencia terapéutica y del autocuidado del paciente. El nefrólogo desempeña un papel clave en la transición en la cistinosis debido a la afectación renal que domina la patología y porque la mayoría de los pacientes han recibido un trasplante renal antes de la edad adulta. Conclusión: Se presenta un documento que establece unas recomendaciones y un cronograma para guiar la transición de los adolescentes y adultos jóvenes con cistinosis en nuestro ámbito.

Animal behavioral tests are essential to understand the bases of neurologic and psychological disorders, which can be evaluated by different methodological and experimental models. However, the quantification of behavioral tests results is limited by the considerable amount of time needed for manual evaluation and the high costs of automated analysis software. To overcome these limitations, we describe here a new, open source toolbox for ImageJ, called Mouse Behavioral Analysis Toolbox (MouBeAT), designed to analyze different behavioral tests in rodents semi-automatically. These tests include Open Field (OF), Elevated Plus Maze (EPM), Y-maze (YM) test and Morris Water Maze (MWM). MouBeAT showed a high correlation with manual evaluation in all the parameters analyzed for all the behavioral tests, reinforcing its value as an accurate analysis tool. This new tool is freely available online.

Increased oxidative stress is a major contributor to the development and progression of heart failure, however, our knowledge on the role of the distinct NADPH oxidase (NOX) isoenzymes, especially on NOX4 is controversial. Therefore, we aimed to characterize NOX4 expression in human samples from healthy and failing hearts. Explanted human heart samples (left and right ventricular, and septal regions) were obtained from patients suffering from heart failure of ischemic or dilated origin. Control samples were obtained from donor hearts that were not used for transplantation. Deep RNA sequencing of the cardiac transcriptome indicated extensive alternative splicing of the NOX4 gene in heart failure as compared to samples from healthy donor hearts. Long distance PCR analysis with a universal 5′-3′ end primer pair, allowing amplification of different splice variants, confirmed the presence of the splice variants. To assess translation of the alternatively spliced transcripts we determined protein expression of NOX4 by using a specific antibody recognizing a conserved region in all variants. Western blot analysis showed up-regulation of the full-length NOX4 in ischemic cardiomyopathy samples and confirmed presence of shorter isoforms both in control and failing samples with disease-associated expression pattern. We describe here for the first time that NOX4 undergoes extensive alternative splicing in human hearts which gives rise to the expression of different enzyme isoforms. The full length NOX4 is significantly upregulated in ischemic cardiomyopathy suggesting a role for NOX4 in ROS production during heart failure.

Introducción: La cistinosis es una enfermedad lisosomal minoritaria de expresión sistémica con especial afectación renal y oftalmológica, en la que los pacientes inician terapia renal sustitutiva en la primera década de la vida en ausencia de tratamiento. El pronóstico de la cistinosis depende del diagnóstico precoz, la pronta instauración del tratamiento con cisteamina y el buen cumplimiento terapéutico. La progresión de la enfermedad renal y de las complicaciones extrarrenales y una menor supervivencia, son más acentuadas en pacientes no adherentes. Objetivo: El objetivo de este trabajo fue la elaboración de unas recomendaciones para la atención integral de la cistinosis y la transición del adolescente a la medicina del adulto, basadas en la experiencia clínica, con el fin de reducir el impacto de la enfermedad y mejorar la calidad de vida y el pronóstico del paciente. Método: Búsqueda bibliográfica y reuniones de consenso de un equipo multidisciplinar de expertos en la práctica clínica con pacientes afectos de cistinosis (Grupo T-CiS.bcn), procedentes de 5 hospitales localizados en Barcelona. Resultados: El documento recoge recomendaciones específicas y necesarias para el diagnóstico, tratamiento y seguimiento multidisciplinar de la cistinosis en las siguientes áreas: nefrología, diálisis, trasplante renal, oftalmología, endocrinología, neurología, laboratorio, consejo genético, enfermería y farmacia. Conclusiones: Disponer de un documento de referencia para la atención integral de la cistinosis constituye una herramienta de soporte para los profesionales de la salud que asisten a estos pacientes. Los principales pilares en los que se sustenta son: a) el enfoque multidisciplinar, b) la adecuada monitorización de la enfermedad y control de los niveles de cistina intraleucocitarios, c) la importancia de la adherencia al tratamiento con cisteamina y d) la promoción del autocuidado del paciente mediante programas de educación en la enfermedad. Todo ello conducirá, en una segunda fase, a la elaboración de un modelo de transición coordinado entre los servicios de pediatría y de adultos que contemple las necesidades específicas de la cistinosis.

Introduction: Cystinosis is a rare systemic lysosomal storage disease that mainly affects the kidney and the eye. Renal replacement therapy is started in patients with cystinosis during the first decade of life in the absence of treatment. The prognosis of cystinosis depends on early diagnosis and the prompt start of and good compliance with cysteamine treatment. Kidney disease progression, extra-renal complications and shorter life expectancy are more pronounced in patients who do not adhere to treatment. Objective: The aim of this work was to establish recommendations for the comprehensive care of cystinosis and facilitate patient transition from paediatric to adult medicine, based on clinical experience. The goal is to reduce the impact of the disease and improve prognosis and patient quality of life. Methods: Bibliographic research and consensus meetings with a multidisciplinary professional team of clinical experts in cystinosis (T-CiS.bcn group) from 5 hospitals in Barcelona. Results: This consensus document gathers specific recommendations for the diagnosis, treatment and multidisciplinary care of cystinotic patients in the following areas: nephrology, dialysis, kidney transplantation, ophthalmology, endocrinology, neurology, laboratory, genetic counselling, nursing and pharmacy. Conclusions: Guidelines for the comprehensive care of cystinosis provide a support tool for health professionals who look after these patients. They are based on the following main pillars: (a) a multidisciplinary approach; (b) appropriate disease monitoring and control of white blood cell (WBC) cystine levels; (c) the importance of adherence to cysteamine treatment; and (d) the promotion of patient self-care by means of disease education programmes. All these recommendations will lead us, in a second phase, to create a coordinated model of transition from paediatric to adult care services which will cover the specific needs of cystinosis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cardiovascular disease (CVD) is a major cause of mortality and hospitalization worldwide. Several risk factors have been identified that are strongly associated with the development of CVD. However, these explain only a fraction of cases, and the focus of research into the causes underlying the unexplained risk has shifted first to genetics and more recently to genomics. A genetic contribution to CVD has long been recognized; however, with the exception of certain conditions that show Mendelian inheritance, it has proved more challenging than anticipated to identify the precise genomic components responsible for the development of CVD. Genome-wide association studies (GWAS) have provided information about specific genetic variations associated with disease, but these are only now beginning to reveal the underlying molecular mechanisms. To fully understand the biological implications of these associations, we need to relate them to the exquisite, multilayered regulation of protein expression, which includes chromatin remodeling, regulatory elements, microRNAs and alternative splicing. Understanding how the information contained in the DNA relates to the operation of these regulatory layers will allow us not only to better predict the development of CVD but also to develop more effective therapies.

The terrestrial cycling of Si is thought to have a large influence on the terrestrial and marine primary production, as well as the coupled biogeochemical cycles of Si and C. Biomineralization of silica is widespread among terrestrial eukaryotes such as plants, soil diatoms, freshwater sponges, silicifying flagellates and testate amoebae. Two major groups of testate (shelled) amoebae, arcellinids and euglyphids, produce their own silica particles to construct shells. The two are unrelated phylogenetically and acquired biomineralizing capabilities independently. Hyalosphenids, a group within arcellinids, are predators of euglyphids. We demonstrate that hyalosphenids can construct shells using silica scales mineralized by the euglyphids. Parsimony analyses of the current hyalosphenid phylogeny indicate that the ability to “steal” euglyphid scales is most likely ancestral in hyalosphenids, implying that euglyphids should be older than hyalosphenids. However, exactly when euglyphids arose is uncertain. Current fossil record contains unambiguous euglyphid fossils that are as old as 50 million years, but older fossils are scarce and difficult to interpret. Poor taxon sampling of euglyphids has also prevented the development of molecular clocks. Here, we present a novel molecular clock reconstruction for arcellinids and consider the uncertainties due to various previously used calibration points. The new molecular clock puts the origin of hyalosphenids in the early Carboniferous (∼370 mya). Notably, this estimate coincides with the widespread colonization of land by Si-accumulating plants, suggesting possible links between the evolution of Arcellinid testate amoebae and the expansion of terrestrial habitats rich in organic matter and bioavailable Si.

Micro-eukaryotic diversity is poorly documented at all taxonomic levels and the phylogenetic affiliation of many taxa - including many well-known and common organisms - remains unknown. Among these incertae sedis taxa are Archerella flavum (Loeblich and Tappan, 1961) and Amphitrema wrightianum (Archer, 1869) (Amphitremidae), two filose testate amoebae commonly found in Sphagnum peatlands. To clarify their phylogenetic position, we amplified and sequenced the SSU rRNA gene obtained from four independent DNA extractions of A. flavum and three independent DNA extractions of A. wrightianum. Our molecular data demonstrate that genera Archerella and Amphitrema form a fully supported deep-branching clade within the Labyrinthulomycetes (Stramenopiles), together with Diplophrys sp. (ATCC50360) and several environmental clones obtained from a wide range of environments. This newly described clade we named Amphitremida is diverse genetically, ecologically and physiologically. Our phylogenetic analysis suggests that osmotrophic species evolved most likely from phagotrophic ancestors and that the bothrosome, an organelle that produces cytoplasmic networks used for attachment to the substratum and to absorb nutrients from the environments, appeared lately in labyrithulomycete evolution.

BACKGROUND:The epicardium has key functions during myocardial development, by contributing to the formation of coronary endothelial and smooth muscle cells, cardiac fibroblasts, and potentially cardiomyocytes. The epicardium plays a morphogenetic role by emitting signals to promote and maintain cardiomyocyte proliferation. In a regenerative context, the adult epicardium might comprise a progenitor cell population that can be induced to contribute to cardiac repair. Although some genes involved in epicardial function have been identified, a detailed molecular profile of epicardial gene expression has not been available. METHODOLOGY:Using laser capture microscopy, we isolated the epicardial layer from the adult murine heart before or after cardiac infarction in wildtype mice and mice expressing a transgenic IGF-1 propeptide (mIGF-1) that enhances cardiac repair, and analyzed the transcription profile using DNA microarrays. PRINCIPAL FINDINGS:Expression of epithelial genes such as basonuclin, dermokine, and glycoprotein M6A are highly enriched in the epicardial layer, which maintains expression of selected embryonic genes involved in epicardial development in mIGF-1 transgenic hearts. After myocardial infarct, a subset of differentially expressed genes are down-regulated in the epicardium representing an epicardium-specific signature that responds to injury. CONCLUSION:This study presents the description of the murine epicardial transcriptome obtained from snap frozen tissues, providing essential information for further analysis of this important cardiac cell layer.