Structural insights into the cTAR DNA recognition by the HIV-1 nucleocapsid protein: role of sugar deoxyriboses in the binding polarity of NC

An essential step of the reverse transcription of the HIV-1 genome is the first strand transfer that requires the annealing of the TAR RNA hairpin to the cTAR DNA hairpin. HIV-1 nucleocapsid protein (NC) plays a crucial role by facilitating annealing of the complementary hairpins. Using nuclear magnetic resonance and gel retardation assays, we investigated the interaction between NC and the top half of the cTAR DNA (mini-cTAR). We show that NC(11-55) binds the TGG sequence in the lower stem that is destabilized by the adjacent internal loop. The 5′ thymine interacts with residues of the N-terminal zinc knuckle and the 3′ guanine is inserted in the hydrophobic plateau of the C-terminal zinc knuckle. The TGG sequence is preferred relative to the apical and internal loops containing unpaired guanines. Investigation of the DNA–protein contacts shows the major role of hydrophobic interactions involving nucleobases and deoxyribose sugars. A similar network of hydrophobic contacts is observed in the published NC:DNA complexes, whereas NC contacts ribose differently in NC:RNA complexes. We propose that the binding polarity of NC is related to these contacts that could be responsible for the preferential binding to single-stranded nucleic acids

Žonglieriaus ir Sganarelio figūros, sujungtos draugėn, kaip rašytojo šifras

Visą Romaino Gary kūrybą persmelkia identiteto klausimas. Rašytojas dažnai imasi romano žanro (pikareskos) herojaus kaip paradigmos, kuri išreikštų jo, žmogaus ir rašytojo, lygiai kaip ir personažų, veikimo būdą. Sganarelis – antiherojaus (isp. picaro) metamorfozė, teatrališkas personažas, kurio vardu pavadintas savotiško literatūrinio traktato Brolis Okeanas (Frère Océan) pirmas tomas. Jis taip pat ir žonglierius, kurį Gary pristato kaip meninių galių žadintoją romane Aušros pažadas (La Promesse de l‘aube), kuris mums siūlo įdomų tyrimo objektą, nurodomą paantrašte Sganareliui: personažo ir romano beieškant. Viena vertus, jis eksplicitiškai susijęs su Sganareliu, septynių Molière’o pjesių veikėju, ir paties Molière’o scenoje vaidintu personažu, kita vertus, pabrėžtinu artisto gestu apibendrina esmines literatūrines Romaino Gary koncepcijas: rašytojo pasikartojimą personažuose, adresanto ir jo tapatybės maskavimą, kūrybos dinamiškumą bei trapumą ir jos iššūkius realybės įstatymams. Rizikuojama, kad rašytojas peržengs paskutinį tabu – visiškai sujungs savo gyvenimą su kūriniu, kurį priims kaip realybę, ir tuo būdu save pasmerks

Nathalie Sarraute (à la recherche de l'être perdu : exploration de l'expression dramatique du tropisme dans les oeuvres romanesques et théâtrales)

BREST-BU Lettres (290192101) / SudocQUIMPER-BU (292322101) / SudocSudocFranceF

TGFβ inhibition and mesenchymal to epithelial transition initiation by Xenopus egg extract: first steps towards early reprogramming in fish somatic cell

Abstract Xenopus egg extract is a powerful material to modify cultured cells fate and to induce cellular reprogramming in mammals. In this study, the response of goldfish fin cells to in vitro exposure to Xenopus egg extract, and subsequent culture, was studied using a cDNA microarray approach, gene ontology and KEGG pathways analyses, and qPCR validation. We observed that several actors of the TGFβ and Wnt/β-catenin signaling pathways, as well as some mesenchymal markers, were inhibited in treated cells, while several epithelial markers were upregulated. This was associated with morphological changes of the cells in culture, suggesting that egg extract drove cultured fin cells towards a mesenchymal-epithelial transition. This indicates that Xenopus egg extract treatment relieved some barriers of somatic reprogramming in fish cells. However, the lack of re-expression of pou2 and nanog pluripotency markers, the absence of DNA methylation remodeling of their promoter region, and the strong decrease in de novo lipid biosynthesis metabolism, indicate that reprogramming was only partial. The observed changes may render these treated cells more suitable for studies on in vivo reprogramming after somatic cell nuclear transfer

Reprogramming of fish somatic cells for nuclear transfer is primed by Xenopus egg extract

Somatic cell reprogramming in vitro prior to nuclear transfer is one strategy expected to improve clone survival during development. In this study, we investigated the reprogramming extent of fish fin somatic cells after in vitro exposure to Xenopus egg extract and subsequent culture. Using a cDNA microarray approach, we observed drastic changes in the gene expression profile of the treated cells. Several actors of the TGFβ and Wnt/β-catenin signaling pathways, as well as some mesenchymal markers, were inhibited in treated cells, while several epithelial markers were upregulated. This was associated with morphological changes of the cells in culture, suggesting that egg extract drove somatic cells towards a mesenchymal-epithelial transition (MET), the hallmark of somatic reprogramming in induced pluripotent stem cells (iPSCs). However, treated cells were also characterized by a strong decrease in de novo lipid biosynthesis metabolism, the lack of re-expression of pou2 and nanog pluripotency markers, and absence of DNA methylation remodeling of their promoter region. In all, this study showed that Xenopus egg extract treatment initiated an in vitro reprogramming of fin somatic cells in culture. Although not thorough, the induced changes have primed the somatic chromatin for a better embryonic reprogramming upon nuclear transfer

Contribution of functional genomics to the understanding of gonadal sex differentiation in the rainbow trout

International audienc

Contribution of functional genomics to the understanding of gonadal sex differentiation in the rainbow trout

International audienc

Low cardiac index and stroke volume on admission are associated with poor outcome in critically ill burn patients: a retrospective cohort study.

BackgroundImpact of early systemic hemodynamic alterations and fluid resuscitation on outcome in the modern burn care remains controversial. We investigate the association between acute-phase systemic hemodynamics, timing of fluid resuscitation and outcome in critically ill burn patients.MethodsRetrospective, single-center cohort study was conducted in a university hospital. Forty critically ill burn patients with total body surface area (TBSA) burn-injured >20 % with invasive blood pressure and cardiac output monitoring (transpulmonary thermodilution technique) within 8 h from trauma were included. We retrospectively examined hemodynamic variables during the first 24 h following admission, and their association with 90-day mortality.ResultsThe median (interquartile range 25th-75th percentile) TBSA, Simplified Acute Physiology Score II (SAPS II) and Abbreviated Burn Severity Index of the study population were 41 (29-56), 31 (23-50) and 9 (7-11) %, respectively. 90-Day mortality was 42 %. There was no statistical difference between the median pre-hospital and 24-h administered fluid volume in survivors and non-survivors. On admission, stroke volume (SV), cardiac index (CI), oxygen delivery index and mean arterial pressure (MAP) were significantly lower in patients who died despite similar fluid resuscitation volume. ROC curves comparing the ability of initial SV, CI, MAP and lactate to discriminate 90-day mortality gave areas under curves of, respectively, 0.89 (CI 0.77-1), 0.77 (CI 0.58-0.95), 0.73 (CI 0.53-0.93) and 0.78 (CI 0.63-0.92); (p value <0.05 for all). In multivariate analysis, SAPS II and initial SV were independently associated with 90-day mortality (best cutoff value for SV was 27 mL, sensitivity 92 %, specificity 69 %). During 24 h, no interaction was found between time and outcome regarding macrocirculatory parameters changes. Hemodynamic parameters improved during the first 24-h resuscitation in all patients but patients who died had lower SV and CI on admission, which remained through the first 24 h.ConclusionLow initial SV and CI were associated with poor outcome in critically ill burn patients. Very early hemodynamic monitoring may in help detecting under-resuscitated patients. Future prospective interventional studies should explore the impact of early goal-directed therapy in these specific patients

Urine sodium concentration to predict fluid responsiveness in oliguric ICU patients: a prospective multicenter observational study

International audienceBackground: Oliguria is one of the leading triggers of fluid loading in patients in the intensive care unit (ICU). The purpose of this study was to assess the predictive value of urine Na+ (uNa(+)) and other routine urine biomarkers for cardiac fluid responsiveness in oliguric ICU patients. Methods: We conducted a prospective multicenter observational study in five university ICUs. Patients with urine output (UO) 65 mmHg received a fluid challenge. Cardiac fluid responsiveness was defined by an increase in stroke volume >15 % after fluid challenge. Urine and plasma biochemistry samples were examined before fluid challenge. We examined renal fluid responsiveness (defined as UO >0.5 ml/kg/h for 3 consecutive hours) after fluid challenge as a secondary endpoint. Results: Fifty-four patients (age 51 +/- 37 years, Simplified Acute Physiology Score II score 40 +/- 20) were included. Most patients (72 %) were not cardiac responders (CRs), and 50 % were renal responders (RRs) to fluid challenge. Patient characteristics were similar between CRs and cardiac nonresponders. uNa(+) (37 +/- 38 mmol/L vs 25 +/- 75 mmol/L, p = 0.44) and fractional excretion of sodium (FENa+) (2.27 +/- 2.5 % vs 2.15 +/- 5.0 %, p = 0.94) were not statistically different between those who did and those who did not respond to the fluid challenge. Areas under the receiver operating characteristic (AUROC) curves were 0.51 (95 % CI 0.35-0.68) and 0.56 (95 % CI 0.39-0.73) for uNa(+) and FENa+, respectively. Fractional excretion of urea had an AUROC curve of 0.70 (95 % CI 0.54-0.86, p = 0.03) for CRs. Baseline UO was higher in RRs than in renal nonresponders (1.07 +/- 0.78 ml/kg/3 h vs 0.65 +/- 0.53 ml/kg/3 h, p = 0.01). The AUROC curve for RRs was 0.65 (95 % CI 0.53-0.78) for uNa(+). Conclusions: In the present study, most oliguric patients were not CRs and half were not renal responders to fluid challenge. Routine urinary biomarkers were not predictive of fluid responsiveness in oliguric normotensive ICU patients

MOESM3 of Low cardiac index and stroke volume on admission are associated with poor outcome in critically ill burn patients: a retrospective cohort study

Additional file 3: Table S1. Characteristics of the main clinical studies assessing the association between hemodynamics on admission and outcome in critically ill burn patients