Characterisation of the mantle transcriptome and biomineralisation genes in the blunt-gaper clam, Mya truncata

Members of the Myidae family are ecologically and economically important, but there is currently very little molecular data on these species. The present study sequenced and assembled the mantle transcriptome of Mya truncata from the North West coast of Scotland and identified candidate biomineralisation genes. RNA-Seq reads were assembled to create 20,106 contigs in a de novo transciptome, 18.81% of which were assigned putative functions using BLAST sequence similarity searching (cuttoff E-value 1E − 10). The most highly expressed genes were compared to the Antarctic clam (Laternula elliptica) and showed that many of the dominant biological functions (muscle contraction, energy production, biomineralisation) in the mantle were conserved. There were however, differences in the constitutive expression of heat shock proteins, which were possibly due to the M. truncata sampling location being at a relatively low latitude, and hence relatively warm, in terms of the global distribution of the species. Phylogenetic analyses of the Tyrosinase proteins from M. truncata showed a gene expansion which was absent in L. elliptica. The tissue distribution expression patterns of putative biomineralisation genes were investigated using quantitative PCR, all genes showed a mantle specific expression pattern supporting their hypothesised role in shell secretion. The present study provides some preliminary insights into how clams from different environments – temperate versus polar – build their shells. In addition, the transcriptome data provides a valuable resource for future comparative studies investigating biomineralisation

Shell matrix proteins of the clam, Mya truncata: Roles beyond shell formation through proteomic study

Mya truncata, a soft shell clam, is presented as a new model to study biomineralization through a proteomics approach. In this study, the shell and mantle tissue were analysed in order to retrieve knowledge about the secretion of shell matrix proteins (SMPs). Out of 67 and 127 shell and mantle proteins respectively, 16 were found in both shell and mantle. Bioinformatic analysis of SMP sequences for domain prediction revealed the presence of several new domains such as fucolectin tachylectin-4 pentraxin-1 (FTP), scavenger receptor, alpha-2-macroglobulin (α2 M), lipocalin and myosin tail along with previously reported SMP domains such as chitinase, carbonic anhydrase, tyrosinase, sushi, and chitin binding. Interestingly, these newly predicted domains are attributed with molecular functions other than biomineralization. These findings suggest that shells may not only act as protective armour from predatory action, but could also actively be related to other functions such as immunity. In this context, the roles of SMPs in biomineralization need to be looked in a new perspective

Fractalkine Expression Induces Endothelial Progenitor Cell Lysis by Natural Killer Cells

BACKGROUND: Circulating CD34(+) cells, a population that includes endothelial progenitors, participate in the maintenance of endothelial integrity. Better understanding of the mechanisms that regulate their survival is crucial to improve their regenerative activity in cardiovascular and renal diseases. Chemokine-receptor cross talk is critical in regulating cell homeostasis. We hypothesized that cell surface expression of the chemokine fractalkine (FKN) could target progenitor cell injury by Natural Killer (NK) cells, thereby limiting their availability for vascular repair. METHODOLOGY/PRINCIPAL FINDINGS: We show that CD34(+)-derived Endothelial Colony Forming Cells (ECFC) can express FKN in response to TNF-α and IFN-γ inflammatory cytokines and that FKN expression by ECFC stimulates NK cell adhesion, NK cell-mediated ECFC lysis and microparticles release in vitro. The specific involvement of membrane FKN in these processes was demonstrated using FKN-transfected ECFC and anti-FKN blocking antibody. FKN expression was also evidenced on circulating CD34(+) progenitor cells and was detected at higher frequency in kidney transplant recipients, when compared to healthy controls. The proportion of CD34(+) cells expressing FKN was identified as an independent variable inversely correlated to CD34(+) progenitor cell count. We further showed that treatment of CD34(+) circulating cells isolated from adult blood donors with transplant serum or TNF-α/IFN-γ can induce FKN expression. CONCLUSIONS: Our data highlights a novel mechanism by which FKN expression on CD34(+) progenitor cells may target their NK cell mediated killing and participate to their immune depletion in transplant recipients. Considering the numerous diseased contexts shown to promote FKN expression, our data identify FKN as a hallmark of altered progenitor cell homeostasis with potential implications in better evaluation of vascular repair in patients

Roles and practices of general practitioners and psychiatrists in management of depression in the community

BACKGROUND: Little is known about depressed patients' profiles and how they are managed. The aim of the study is to compare GPs and psychiatrists for 1°) sociodemographic and clinical profile of their patients considered as depressed 2°) patterns of care provision. METHODS: The study design is an observational cross-sectional study on a random sample of GPs and psychiatrists working in France. Consecutive inclusion of patients seen in consultation considered as depressed by the physician. GPs enrolled 6,104 and psychiatrists 1,433 patients. Data collected: sociodemographics, psychiatric profile, environmental risk factors of depression and treatment. All clinical data were collected by participating physicians; there was no direct independent clinical assessment of patients to check the diagnosis of depressive disorder. RESULTS: Compared to patients identified as depressed by GPs, those identified by psychiatrists were younger, more often urban (10.5% v 5.4% – OR = 2.4), educated (42.4% v 25.4% – OR = 3.9), met DSM-IV criteria for depression (94.6% v 85.6% – OR = 2.9), had been hospitalized for depression (26.1% v 15.6% – OR = 2.0) and were younger at onset of depressive problems (all adjusted p < .001). No difference was found for psychiatric and somatic comorbidity, suicide attempt and severity of current depression. Compared to GPs, psychiatrists more often prescribed tricyclics and very novel antidepressants (7.8% v 2.3% OR = 5.0 and 6.8% v 3.0% OR = 3.8) with longer duration of antidepressant treatment. GPs' patients received more "non-conventional" treatment (8.8% v 2.4% OR = 0.3) and less psychotherapy (72.2% v 89.1% OR = 3.1) (all adjusted p < .001). CONCLUSION: Differences between patients mainly concerned educational level and area of residence with few differences regarding clinical profile. Differences between practices of GPs and psychiatrists appear to reflect more the organization of the French care system than the competence of providers

Deciphering mollusc shell production: the roles of genetic mechanisms through to ecology, aquaculture and biomimetics

Most molluscs possess shells, constructed from a vast array of microstructures and architectures. The fully formed shell is composed of calcite or aragonite. These CaCO3 crystals form complex biocomposites with proteins, which although typically less than 5% of total shell mass, play significant roles in determining shell microstructure. Despite much research effort, large knowledge gaps remain in how molluscs construct and maintain their shells, and how they produce such a great diversity of forms. Here we synthesize results on how shell shape, microstructure, composition and organic content vary among, and within, species in response to numerous biotic and abiotic factors. At the local level, temperature, food supply and predation cues significantly affect shell morphology, whilst salinity has a much stronger influence across latitudes. Moreover, we emphasize how advances in genomic technologies [e.g. restriction site-associated DNA sequencing (RAD-Seq) and epigenetics] allow detailed examinations of whether morphological changes result from phenotypic plasticity or genetic adaptation, or a combination of these. RAD-Seq has already identified single nucleotide polymorphisms associated with temperature and aquaculture practices, whilst epigenetic processes have been shown significantly to modify shell construction to local conditions in, for example, Antarctica and New Zealand. We also synthesize results on the costs of shell construction and explore how these affect energetic trade-offs in animal metabolism. The cellular costs are still debated, with CaCO3 precipitation estimates ranging from 1-2 J/mg to 17-55 J/mg depending on experimental and environmental conditions. However, organic components are more expensive (~29 J/mg) and recent data indicate transmembrane calcium ion transporters can involve considerable costs. This review emphasizes the role that molecular analyses have played in demonstrating multiple evolutionary origins of biomineralization genes. Although these are characterized by lineage-specific proteins and unique combinations of co-opted genes, a small set of protein domains have been identified as a conserved biomineralization tool box. We further highlight the use of sequence data sets in providing candidate genes for in situ localization and protein function studies. The former has elucidated gene expression modularity in mantle tissue, improving understanding of the diversity of shell morphology synthesis. RNA interference (RNAi) and clustered regularly interspersed short palindromic repeats - CRISPR-associated protein 9 (CRISPR-Cas9) experiments have provided proof of concept for use in the functional investigation of mollusc gene sequences, showing for example that Pif (aragonite-binding) protein plays a significant role in structured nacre crystal growth and that the Lsdia1 gene sets shell chirality in Lymnaea stagnalis. Much research has focused on the impacts of ocean acidification on molluscs. Initial studies were predominantly pessimistic for future molluscan biodiversity. However, more sophisticated experiments incorporating selective breeding and multiple generations are identifying subtle effects and that variability within mollusc genomes has potential for adaption to future conditions. Furthermore, we highlight recent historical studies based on museum collections that demonstrate a greater resilience of molluscs to climate change compared with experimental data. The future of mollusc research lies not solely with ecological investigations into biodiversity, and this review synthesizes knowledge across disciplines to understand biomineralization. It spans research ranging from evolution and development, through predictions of biodiversity prospects and future-proofing of aquaculture to identifying new biomimetic opportunities and societal benefits from recycling shell products.FCT: UID/Multi/04326/2019; European Marine Biological Research Infrastructure Cluster-EMBRIC (EU H2020 research and innovation program) 654008; European Union Seventh Framework Programme [FP7] ITN project 'CACHE: Calcium in a Changing Environment' under REA 60505; NERC Natural Environment Research Council NE/J500173/1info:eu-repo/semantics/publishedVersio

Evidence of a causal and modifiable relationship between kidney function and circulating trimethylamine N-oxide

The host-microbiota co-metabolite trimethylamine N-oxide (TMAO) is linked to increased cardiovascular risk but how its circulating levels are regulated remains unclear. We applied "explainable" machine learning, univariate, multivariate and mediation analyses of fasting plasma TMAO concentration and a multitude of phenotypes in 1,741 adult Europeans of the MetaCardis study. Here we show that next to age, kidney function is the primary variable predicting circulating TMAO, with microbiota composition and diet playing minor, albeit significant, roles. Mediation analysis suggests a causal relationship between TMAO and kidney function that we corroborate in preclinical models where TMAO exposure increases kidney scarring. Consistent with our findings, patients receiving glucose-lowering drugs with reno-protective properties have significantly lower circulating TMAO when compared to propensity-score matched control individuals. Our analyses uncover a bidirectional relationship between kidney function and TMAO that can potentially be modified by reno-protective anti-diabetic drugs and suggest a clinically actionable intervention for decreasing TMAO-associated excess cardiovascular risk

Imidazole propionate is increased in diabetes and associated with dietary patterns and altered microbial ecology

Microbiota-host-diet interactions contribute to the development of metabolic diseases. Imidazole propionate is a novel microbially produced metabolite from histidine, which impairs glucose metabolism. Here, we show that subjects with prediabetes and diabetes in the MetaCardis cohort from three European countries have elevated serum imidazole propionate levels. Furthermore, imidazole propionate levels were increased in subjects with low bacterial gene richness and Bacteroides 2 enterotype, which have previously been associated with obesity. The Bacteroides 2 enterotype was also associated with increased abundance of the genes involved in imidazole propionate biosynthesis from dietary histidine. Since patients and controls did not differ in their histidine dietary intake, the elevated levels of imidazole propionate in type 2 diabetes likely reflects altered microbial metabolism of histidine, rather than histidine intake per se. Thus the microbiota may contribute to type 2 diabetes by generating imidazole propionate that can modulate host inflammation and metabolism

Etude hodologique du complexe octavolateral au cours de la metamorphose chez trois amphibiens anoures: Xenopus laevis (Pipidae), Discoglossus pictus (Discoglossidae), Gastrotheca riobambae (Hylidae)

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84778 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Association céréale-légumineuse : caractériser les farines pour mieux les transformer

Association céréale-légumineuse : caractériser les farines pour mieux les transforme