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

Ubiquitin Fusion Degradation Protein 1 as a Blood Marker for The Early Diagnosis of Ischemic Stroke

Background: Efficacy of thrombolysis in acute ischemic stroke is strongly related to physician’s ability to make an accurate diagnosis and to intervene within 3–6 h after event onset. In this context, the discovery and validation of very early blood markers have recently become an urgent, yet unmet, goal of stroke research. Ubiquitin fusion degradation protein 1 is increased in human postmortem CSF, a model of global brain insult, suggesting that its measurement in blood may prove useful as a biomarker of stroke.Methods: Enzyme-linked immunosorbent assay (ELISA) was used to measure UFD1 in plasma and sera in three independent cohorts, European (Swiss and Spanish) and North-American retrospective analysis encompassing a total of 123 consecutive stroke and 90 control subjects.Results: Highly significant increase of ubiquitin fusion degradation protein 1 (UFD1) was found in Swiss stroke patients with 71% sensitivity (95% CI, 52–85.8%), and 90% specificity (95% CI, 74.2–98%) (N = 31, p < 0.0001). Significantly elevated concentration of this marker was then validated in Spanish (N = 39, p < 0.0001, 95% sensitivity (95% CI, 82.7–99.4%)), 76% specificity (95% CI, 56.5–89.7%)) and North-American stroke patients (N = 53, 62% sensitivity (95% CI, 47.9–75.2%), 90% specificity (95% CI, 73.5–97.9%), p < 0.0001). Its concentration was increased within 3 h of stroke onset, on both the Swiss (p < 0.0001) and Spanish (p = 0.0004) cohorts.Conclusions: UFD1 emerges as a reliable plasma biomarker for the early diagnosis of stroke, and in the future, might be used in conjunction with clinical assessments, neuroimaging and other blood markers.Abbreviations: AUC: area under curve; BBB: blood–brain barrier; CO: cut-off; CSF: cerebrospinal fluid; CT: computerized tomography; H-FABP: heart-fatty acid binding protein; MMP9: matrix metalloproteinase 9; MRI: magnetic resonance imaging; NDKA: nucleotide diphosphate kinase A; OR: odds ratio; RFU: relative fluorescence units; ROC: receiver operating characteristic; rtPA: recombinant tissue plasminogen activator; SE: sensitivity; SP: specificity; TIA: transient ischemic attack; UFD1: ubiquitin fusion degradation protein

HF-EPR, Raman, UV/VIS Light Spectroscopic, and DFT Studies of the Ribonucleotide Reductase R2 Tyrosyl Radical from Epstein-Barr Virus

Epstein-Barr virus (EBV) belongs to the gamma subfamily of herpes viruses, among the most common pathogenic viruses in humans worldwide. The viral ribonucleotide reductase small subunit (RNR R2) is involved in the biosynthesis of nucleotides, the DNA precursors necessary for viral replication, and is an important drug target for EBV. RNR R2 generates a stable tyrosyl radical required for enzymatic turnover. Here, the electronic and magnetic properties of the tyrosyl radical in EBV R2 have been determined by X-band and high-field/high-frequency electron paramagnetic resonance (EPR) spectroscopy recorded at cryogenic temperatures. The radical exhibits an unusually low g1-tensor component at 2.0080, indicative of a positive charge in the vicinity of the radical. Consistent with these EPR results a relatively high C-O stretching frequency associated with the phenoxyl radical (at 1508 cm−1) is observed with resonance Raman spectroscopy. In contrast to mouse R2, EBV R2 does not show a deuterium shift in the resonance Raman spectra. Thus, the presence of a water molecule as a hydrogen bond donor moiety could not be identified unequivocally. Theoretical simulations showed that a water molecule placed at a distance of 2.6 Å from the tyrosyl-oxygen does not result in a detectable deuterium shift in the calculated Raman spectra. UV/VIS light spectroscopic studies with metal chelators and tyrosyl radical scavengers are consistent with a more accessible dimetal binding/radical site and a lower affinity for Fe2+ in EBV R2 than in Escherichia coli R2. Comparison with previous studies of RNR R2s from mouse, bacteria, and herpes viruses, demonstrates that finely tuned electronic properties of the radical exist within the same RNR R2 Ia class

Spectroscopic Studies of the Iron and Manganese Reconstituted Tyrosyl Radical in Bacillus Cereus Ribonucleotide Reductase R2 Protein

Ribonucleotide reductase (RNR) catalyzes the rate limiting step in DNA synthesis where ribonucleotides are reduced to the corresponding deoxyribonucleotides. Class Ib RNRs consist of two homodimeric subunits: R1E, which houses the active site; and R2F, which contains a metallo cofactor and a tyrosyl radical that initiates the ribonucleotide reduction reaction. We studied the R2F subunit of B. cereus reconstituted with iron or alternatively with manganese ions, then subsequently reacted with molecular oxygen to generate two tyrosyl-radicals. The two similar X-band EPR spectra did not change significantly over 4 to 50 K. From the 285 GHz EPR spectrum of the iron form, a g1-value of 2.0090 for the tyrosyl radical was extracted. This g1-value is similar to that observed in class Ia E. coli R2 and class Ib R2Fs with iron-oxygen cluster, suggesting the absence of hydrogen bond to the phenoxyl group. This was confirmed by resonance Raman spectroscopy, where the stretching vibration associated to the radical (C-O, ν7a = 1500 cm−1) was found to be insensitive to deuterium-oxide exchange. Additionally, the 18O-sensitive Fe-O-Fe symmetric stretching (483 cm−1) of the metallo-cofactor was also insensitive to deuterium-oxide exchange indicating no hydrogen bonding to the di-iron-oxygen cluster, and thus, different from mouse R2 with a hydrogen bonded cluster. The HF-EPR spectrum of the manganese reconstituted RNR R2F gave a g1-value of ∼2.0094. The tyrosyl radical microwave power saturation behavior of the iron-oxygen cluster form was as observed in class Ia R2, with diamagnetic di-ferric cluster ground state, while the properties of the manganese reconstituted form indicated a magnetic ground state of the manganese-cluster. The recent activity measurements (Crona et al., (2011) J Biol Chem 286: 33053–33060) indicates that both the manganese and iron reconstituted RNR R2F could be functional. The manganese form might be very important, as it has 8 times higher activity

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Strategic discourse and the making of strategy

International audienceTo what extent and how communication, and in particular strategic discourses, contribute to the making of strategy? Does talking of strategy help the doing of strategy? In this chapter, we rely on Austin’s view of performativity and use it as a framework to comprehend the effects of strategic discourses on strategic outcomes. Using this framework, we critically review past works to appreciate to what extent and how strategic discourses can be said to be performative. This analysis reveals a paradox: On the one hand, while many managers believe adopting the ‘rules of statements’ of strategy discourse will engender the reality they describe, research shows it is rarely the case – strategic discourses have limited illocutionary power. On the other hand, strategic discourses have important perlocutionary effects – for instance, they have significant impact on organizational members’ identity

Strategic discourse and the making of strategy

International audienceTo what extent and how communication, and in particular strategic discourses, contribute to the making of strategy? Does talking of strategy help the doing of strategy? In this chapter, we rely on Austin’s view of performativity and use it as a framework to comprehend the effects of strategic discourses on strategic outcomes. Using this framework, we critically review past works to appreciate to what extent and how strategic discourses can be said to be performative. This analysis reveals a paradox: On the one hand, while many managers believe adopting the ‘rules of statements’ of strategy discourse will engender the reality they describe, research shows it is rarely the case – strategic discourses have limited illocutionary power. On the other hand, strategic discourses have important perlocutionary effects – for instance, they have significant impact on organizational members’ identity

Strategizing

International audienceIn this chapter, we use Austin’s view of performativity as a framework to comprehend the effects of strategic discourse on strategic outcomes. Our review of the literature reveals a paradox: On the one hand, and contrary to what many managers believe, strategic discourses have limited illocutionary power - they seldom engender the reality they describe. On the other hand, strategic discourses have important perlocutionary effects - for instance, they have a significant impact on organizational members’ identity. In the conclusion of our chapter, we outline some avenues for future research on the performativity of strategic discourses

L'organisation des soins primaires (le pôle de santé, une réponse aux attentes des professionnels?)

Introduction: Notre étude a pour objectif de comprendre les motivations, les attentes et les difficultés de professionnels regroupés au sein d'un pôle de santé, dans un contexte de mutation des soins primaires. Matériel et Méthode: Une enquête qualitative sur la base d'entretiens a été menée auprès des professionnels du pôle de santé de Saint Méen le Grand. Résultats: Le pôle de santé a été créé sur un territoire particulier et grâce à un professionnel leader . Les attentes sont centrées sur l'amélioration de la prise en charge des patients et de la qualité de vie des professionnels. Des difficultés sont mises en avant: une organisation chronophage, des implications variables au sein du groupe et un financement peu visible. Conclusion: L'exercice au sein d'un pôle de santé semble être une solution pour répondre aux nouveaux besoins de santé. Mais des difficultés sont encore à résoudre: le problème de la généralisation de ce type de structure et l'absence d'autonomie financière.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Heart-fatty acid-binding protein as a marker for early detection of acute myocardial infarction and stroke

Heart-fatty acid-binding protein (H-FABP) is a small cytosolic protein involved in intracellular fatty acid transport. This protein, highly concentrated in the heart, is quickly released into plasma after myocardial injury. Results from numerous studies suggest that H-FABP is an excellent marker for the early detection of myocardial damage. H-FABP is also expressed in the brain, although in lower concentrations than in the heart. Recent preliminary studies also investigated the usefulness of H-FABP for the diagnosis of acute and chronic neurological disorders. These potential applications of H-FABP in clinical practice are reviewed in this article, with a strong focus on the early diagnosis of acute myocardial infarction and stroke