Increase of mitochondrial DNA content and transcripts in early bovine embryogenesis associated with upregulation of mtTFA and NRF1 transcription factors

BACKGROUND: Recent work has shown that mitochondrial biogenesis and mitochondrial functions are critical determinants of embryonic development. However, the expression of the factors controlling mitochondrial biogenesis in early embryogenesis has received little attention so far. METHODS: We used real-time quantitative PCR to quantify mitochondrial DNA (mtDNA) in bovine oocytes and in various stages of in vitro produced embryos. To investigate the molecular mechanisms responsible for the replication and the transcriptional activation of mtDNA, we quantified the mRNA corresponding to the mtDNA-encoded cytochrome oxidase 1 (COX1), and two nuclear-encoded factors, i.e. the Nuclear Respiratory Factor 1 (NRF1), and the nuclear-encoded Mitochondrial Transcription Factor A (mtTFA). RESULTS: Unlike findings reported in mouse embryos, the mtDNA content was not constant during early bovine embryogenesis. We found a sharp, 60% decrease in mtDNA content between the 2-cell and the 4/8-cell stages. COX1 mRNA was constant until the morula stage after which it increased dramatically. mtTFA mRNA was undetectable in oocytes and remained so until the 8/16-cell stage; it began to appear only at the morula stage, suggesting de novo synthesis. In contrast, NRF1 mRNA was detectable in oocytes and the quantity remained constant until the morula stage. CONCLUSION: Our results revealed a reduction of mtDNA content in early bovine embryos suggesting an active process of mitochondrial DNA degradation. In addition, de novo mtTFA expression associated with mitochondrial biogenesis activation and high levels of NRF1 mRNA from the oocyte stage onwards argue for the essential function of these factors during the first steps of bovine embryogenesis

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Etude des liens entre les systèmes visuel et proprioceptif : approche électrophysiologique et comportementale chez le sujet sain et le patient amputé du membre supérieur

Le codage de la position et des mouvements des différents segments corporels implique l'intervention coordonnée des systèmes perceptifs visuel et proprioceptif. L'objectif de ce travail de thèse était de caractériser la nature de ces interactions dans le contrôle moteur. Notre démarche, basée sur une investigation par les potentiels évoqués consistait à mesurer l'activité électrique du cortex moteur primaire lors d'une activité visuomotrice. Nous avons pu montrer que la simple vue d'un effecteur (e.g., main) suffit pour provoquer une planification motrice dans le cortex moteur correspondant, qu il s'agisse effectivement de l'effecteur ou qu il s'agisse d'une image reconstituée artificiellement, par le biais d'un miroir reflétant la main opposée, par exemple. Ces résultats attestent de l'influence de la vision sur les processus de planification du mouvement et fournissent une mesure objective des effets de la vision sur le cortex moteur. Dans un second temps, nous avons étudié l'influence du feedback visuel lorsque le membre est absent, avec des patients amputés du membre supérieur. Cette approche nous a permis d'évaluer l'impact de l'expérience perceptive en comparant les données d'amputés traumatiques avec celles de personnes agénésiques, dont l'origine de l'absence du membre est congénitale. Ainsi nous montrons que l'activation motrice corticale peut être générée par un feedback visuel du membre absent seulement si le système moteur est (sujets sans déficit sensorimoteur) ou a été fonctionnel (amputés traumatiques). De plus, nous montrons que cette activité corticale reflète une programmation motrice en cohérence avec le mouvement à effectuer. En effet, les performances motrices dans une tâche de dessin en miroir sont meilleures chez ces sujets lorsqu ils ont un feedback sagittal de leur main active (i.e. donnant l'impression de voir leur main absente). Nous proposons que le feedback visuel provoque la réactivation de programmes moteurs existants, en lien avec la main vue et la tâche à réaliser. Ces résultats fournissent une preuve directe de la persistance fonctionnelle des régions dénervées suite à l'amputation traumatique d'un membre.Pas de résum

Assessment of maturity of Loire Valley wine grapes by mid-infrared spectroscopy

Aim: The objective of the present study was to assess the ripening of grapes collected at different stages of maturation between the “véraison” and harvest periods from mid-infrared spectroscopy (MIRS) analysis. Methods and results: Grape berries of Cabernet Franc collected in two locations of the Loire Valley region (Touraine and Anjou), from 28 vine plots and during two vintages (2005 and 2006) were analysed. With principal component analysis (PCA) of spectral data of grape musts, different levels of ripening were described during the three to four weeks before harvest. A separation according to origin (Touraine or Anjou) was also observed and confirmed by the results of partial least squares (PLS) discriminant analysis (88 % of correct classification). Similar evolutions and geographical discriminations were obtained for specific physicochemical parameters. By PLS regression, good predictions of titratable acidity and sugar concentration from berry spectral data were obtained, with root mean square error of prediction (RMSEP) of 0.53 g/L for titratable acidity (expressed in H2SO4) and 8 g/L for sugar concentration. Moreover, when the data from only one of the regions were considered, the predictions of titratable acidity and sugar concentration were improved and those of real acidity (pH) and maturity index were then satisfactory. The RMSEP values for samples from Touraine and Anjou were reduced, respectively, to 0.05 and 0.02 units for pH, 0.4 and 0.12 g/L for titratable acidity (expressed in H2SO4), 6.6 and 3.2 g/L for sugar concentration, and 5 and 2.2 units for maturity index. Conclusion: Spectroscopic and classic chemical analyses of grape berries yielded highly similar results. The evolution of berries from “véraison” to harvest can be characterized according to both time course and region. The samples showed similar PCA results for chemical and IR spectra parameters. PLS regression between chemical and spectral data showed that Fourier transform IR is a good method to predict acidity and sugar concentration throughout ripening. And the results for these parameters, as well as for pH, maturity index and anthocyanin concentration, are improved if the regressions are calculated from sample sets restricted to a single growing region. Consequently, a calibration model is required for each grape geographical origin. Significance and impact of the study: The potential of MIRS was demonstrated for the quantification of the main indicators of maturity during berry ripening. Furthermore, these spectra can be used to estimate grape maturity in particular in reference to a spectral database established over several years of study. The association infrared spectroscopy, chemometric methods and database will help to monitor ripening and to determine the optimum harvest date

Mitochondries et reproduction

Les mitochondries jouent un rôle central dans le métabolisme énergétique cellulaire. Une de leurs particularités est de posséder leur propre génome, dont la transmission est exclusivement maternelle. Leur implication dans la reproduction humaine est une notion relativement récente qui suscite un intérêt scientifique et médical croissant. Elles peuvent influencer la qualité des ovocytes et des spermatozoïdes, mais aussi la fécondation et le développement embryonnaire. De nouvelles techniques thérapeutiques telles que le transfert de cytoplasme ovocytaire compromettent fortement la transmission uniparentale de l’ADN mitochondrial et soulèvent d’importantes questions éthiques. Cet article tente de faire le point sur les acquisitions récentes concernant le rôle des mitochondries dans la fertilité et la reproduction humaines.Mitochondria play a primary role in cellular energetic metabolism. They possess their own DNA, which is exclusively maternally transmitted. The relatively recent idea that mitochondria may be directly involved in human reproduction is arousing increasing interest in the scientific and medical community. It has been shown that the functional status of mitochondria contributes to the quality of oocytes and spermatozoa, and plays a part in the process of fertilisation and embryo development. Moreover, new techniques, such as ooplasm transfer, compromise the uniquely maternal inheritance of mitochondrial DNA, raising important ethical questions. This review discusses recent information about mitochondria in the field of human fertility and reproduction

Electron cryo-tomography of microtubule assemblies: automatic segmentation of tomograms with CryoSeg.

PosterInternational audienc

Electron cryo-tomography of microtubule assemblies: automatic segmentation of tomograms with CryoSeg.

PosterInternational audienc

A new model of pre-B acute lymphoblastic leukemia chemically induced in rats.

OBJECTIVE: Although B acute lymphoblastic leukemia (B-ALL) is the most common leukemia among children, no chemically inducible model of this leukemia has yet been described in vivo. METHODS: Leukemia was chemically induced in male WKAH/Hkm rats by a nitrosourea derivative, N-butylnitrosourea (BNU), an alkylating agent, administered orally 5 days a week for 24 weeks. Development of leukemia was monitored by clinical observation, follow-up of blood parameters, and appearance of blast cells in peripheral blood samples. The phenotype of the leukemia was determined by cytological examination, cytochemical reactions, and by immunophenotyping of bone marrow cells using various markers. The feasibility of leukemia transplantation was investigated. Clonality and karyotype analyses were also performed. RESULTS: We observed the appearance of acute leukemia in 60% of the rats treated with BNU. Of these, 65% developed pre-B-ALL, which was serially transplantable to healthy WKAH/Hkm male rats. Karyotype analysis did not reveal clonal abnormalities. Clonality determined by immunoglobulin gene rearrangement sequencing disclosed that the pre-B-ALL were mostly oligoclonal. CONCLUSION: This new in vivo model of inducible pre-B-ALL might be useful for investigating the effects of co-initiating or promoting agents suspected to be involved in leukemia development, and for disclosing new molecular events leading to leukemogenic processes