Multiple short-chain dehydrogenases/reductases are regulated in pathological cardiac hypertrophy.

Cardiac hypertrophy (CH) is an important and independent predictor of morbidity and mortality. Through expression profiling, we recently identified a subset of genes (Dhrs7c, Decr, Dhrs11, Dhrs4, Hsd11b1, Hsd17b10, Hsd17b8, Blvrb, Pecr), all of which are members of the short-chain dehydrogenase/reductase (SDR) superfamily and are highly expressed in the heart, which were significantly dysregulated in a rat model of CH caused by severe aortic valve regurgitation (AR). Here, we studied their expression in various models of CH, as well as factors influencing their regulation. Among the nine SDR genes studied, all but Hsd11b1 were downregulated in CH models (AR rats or mice infused with either isoproterenol or angiotensin II). This regulation showed a clear sex dimorphism, being more evident in males than in females irrespective of CH levels. In neonatal rat cardiomyocytes, we observed that treatment with the alpha-1 adrenergic receptor agonist, phenylephrine, mostly reproduced the observations made in CH animals models. Retinoic acid, on the other hand, stimulated the expression of most of the SDR genes studied, suggesting that their expression may be related to cardiomyocyte differentiation. Indeed, levels of expression were found to be higher in the hearts of adult animals than in neonatal cardiomyocytes. In conclusion, we identified a group of genes modulated in animal models of CH and mostly in males. This could be related to the activation of the fetal gene expression program in pathological CH situations, in which these highly expressed genes are down-regulated in the adult heart

Archaeal Methane Cycling Communities Associated with Gassy Subsurface Sediments of Marennes-Oléron Bay (France)

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2009/publication-6165.pdfInternational audienceIn Marennes-Oleacuteron Bay, a macro-tidal bay located on the French Atlantic coast, kilometer-scale acoustic turbidity reveals an accumulation of free gas in the sediment. Large concentrations of organic matter and rapid sedimentation rates provide ideal settings for biogenic methane cycling. We integrate seismic, sedimentologic, biogeochemical and molecular genetic approaches to determine whether microbial methane cycling is involved in this process. Here we show that the acoustic turbidity upper boundary matched with X-ray facies displaying fissures with the highest methane concentrations, demonstrating the existence of methane bubbles in the sediment. 16S rRNA and mcrA gene clone libraries were dominated by sequences affiliated to the three known ANME lineages and to putative methanogens. Sequences related to the marine benthic group B (MBG-B) and miscellaneous crenarchaeotal group (MCG) were also detected. However, the highest methane concentration facies was the only section where active Archaea were detected, using reverse-transcribed rRNA, indicating that these communities were involved either directly or indirectly in the methane cycling process. Moreover, three metabolically active novel uncultivated lineages, related to putative methane cycling Archaea, could be specifically associated to these methane bearing sediments. As methane cycling Archaea are commonly retrieved from deep subseafloor and methane seep sediment, the study of coastal gassy sediments, could therefore help to define the biogeochemical habitats of deep biosphere communities

Microbial diversity associated with the hydrothermal shrimp Rimicaris exoculata gut and occurrence of a resident microbial community

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/00000/11142/7919.pdfInternational audienceRimicaris exoculata dominates the megafauna of several Mid-Atlantic Ridge hydrothermal sites. Its gut is full of sulphides and iron-oxide particles and harbours microbial communities. Although a trophic symbiosis has been suggested, their role remains unclear. In vivo starvation experiments in pressurized vessels were performed on shrimps from Rainbow and Trans-Atlantic Geotraverse sites in order to expel the transient gut contents. Microbial communities associated with the gut of starved and reference shrimps were compared using 16S rRNA gene libraries and microscopic observations (light, transmission and scanning electron microscopy and FISH analyses). We show that the gut microbiota of shrimps from both sites included mainly Deferribacteres, Mollicutes, Epsilon- and Gammaproteobacteria. For the first time, we have observed filamentous bacteria, inserted between microvilli of gut epithelial cells. They remained after starvation periods in empty guts, suggesting the occurrence of a resident microbial community. The bacterial community composition was the same regardless of the site, except for Gammaproteobacteria retrieved only in Rainbow specimens. We observed a shift in the composition of the microbiota of long-starved specimens, from the dominance of Deferribacteres to the dominance of Gammaproteobacteria. These results reinforce the hypothesis of a symbiotic relationship between R. exoculata and its gut epibionts

Extending the sub-sea-floor biosphere

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2008/publication-4209.pdfInternational audienceSub-sea-floor sediments may contain two-thirds of Earth's total prokaryotic biomass. However, this has its basis in data extrapolation from ~500-meter to 4-kilometer depths, whereas the deepest documented prokaryotes are from only 842 meters. Here, we provide evidence for low concentrations of living prokaryotic cells in the deepest (1626 meters below the sea floor), oldest (111 million years old), and potentially hottest (~100 degrees C) marine sediments investigated. These Newfoundland margin sediments also have DNA sequences related to thermophilic and/or hyperthermophilic Archaea. These form two unique clusters within Pyrococcus and Thermococcus genera, suggesting unknown, uncultured groups are present in deep, hot, marine sediments (~54 degrees to 100 degrees C). Sequences of anaerobic methane-oxidizing Archaea were also present, suggesting a deep biosphere partly supported by methane. These findings demonstrate that the sub-sea-floor biosphere extends to at least 1600 meters below the sea floor and probably deeper, given an upper temperature limit for prokaryotic life of at least 113 degrees C and increasing thermogenic energy supply with depth

L’entraînement en résistance induit des adaptations dans le muscle squelettique chez les personnes atteintes de dystrophie myotonique de type 1

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Comparison of LDL fatty acid and carotenoid concentrations and oxidative resistance of LDL in volunteers from countries with different rates of cardiovascular disease

Within Europe there are differences in cardiovascular disease (CVD) risk between countries and this might be related to dietary habits. Oxidative modification of LDL is suggested to increase the risk of CVD and both the fatty acid and antioxidant content of LDL can affect its oxidation. In the present study, concentration of LDL fatty acid and antioxidant micronutrients (tocopherols and carotenoids) and ex vivo oxidative resistance of LDL (lag phase) was compared in volunteers from five countries with different fruit and vegetable intakes and reported rates of CVD. Eighty volunteers (forty males, forty females per centre), age range 25-45 years, were recruited from France, Northern Ireland, UK, Republic of Ireland, The Netherlands, and Spain, and their LDL composition and lag phase were measured. There were some differences in LDL carotenoid and α-tocopherol concentrations between countries. α-Tocopherol was low and β- + γ-tocopherol were high (P<0·001) in the Dutch subjects. β-Carotene concentrations were significantly different between the French and Spanish volunteers, with French showing the highest and Spanish the lowest concentration. LDL lycopene was not different between centres in contrast to lutein, which was highest in French (twofold that in the Dutch and Spanish and threefold that in Northern Ireland and the Republic of Ireland, P<0·001). However absolute LDL saturated, monounsaturated, polyunsaturated and total unsaturated fatty acid concentrations were different between countries (P<0·001, total unsaturated highest in Northern Ireland) there was little difference in unsaturated:saturated fatty acid concentration ratios and no difference in polyunsaturated:saturated fatty acid concentration ratios. LDL from the Republic of Ireland (a region with a high rate of CVD) had greater resistance to Cu-stimulated oxidation than samples obtained from volunteers in other countries. In conclusion, LDL composition did not predict resistance to Cu-stimulated oxidation, nor is there evidence that LDL from volunteers in countries with lower rates of CVD have greater resistance to oxidatio

cAMP Receptor Protein Controls Vibrio cholerae Gene Expression in Response to Host Colonization

The bacterium Vibrio cholerae is native to aquatic environments and can switch lifestyles to cause disease in humans. Lifestyle switching requires modulation of genetic systems for quorum sensing, intestinal colonization, and toxin production. Much of this regulation occurs at the level of gene expression and is controlled by transcription factors. In this work, we have mapped the binding of cAMP receptor protein (CRP) and RNA polymerase across the V. cholerae genome. We show that CRP is an integral component of the regulatory network that controls lifestyle switching. Focusing on a locus necessary for toxin transport, we demonstrate CRP-dependent regulation of gene expression in response to host colonization. Examination of further CRP-targeted genes reveals that this behavior is commonplace. Hence, CRP is a key regulator of many V. cholerae genes in response to lifestyle changes.Cholera is an infectious disease that is caused by the bacterium Vibrio cholerae. Best known for causing disease in humans, the bacterium is most commonly found in aquatic ecosystems. Hence, humans acquire cholera following ingestion of food or water contaminated with V. cholerae. Transition between an aquatic environment and a human host triggers a lifestyle switch that involves reprogramming of V. cholerae gene expression patterns. This process is controlled by a network of transcription factors. In this paper, we show that the cAMP receptor protein (CRP) is a key regulator of V. cholerae gene expression in response to lifestyle changes

Nutrition for the ageing brain: towards evidence for an optimal diet

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline

Deir el-Médina (2022)

Ce rapport présente les travaux réalisés en 2022 sur le site de Deir el-Médina par la mission archéologique de l’Ifao, en partenariat avec plusieurs institutions européennes, américaines et égyptiennes. Le Comité permanent du MoTA a approuvé le plan d’actions proposé, à savoir l’étude et la restauration de plusieurs monuments, dont la chapelle d’Amennakhte, les tombes TT 8 de Khâ, TT 216 de Neferhotep, TT 217 d’Ipouy, TT 265 d’Amenemipet et le temple ptolémaïque, ainsi que l’étude du mobilier..