Follicular dynamics in Serrana goats

Twenty-two Serrana goats were studied through two successive estrous cycles in order to characterize their follicular dynamics during the breeding season. The ovaries of the goats were scanned daily by realtime ultrasonography and all follicles ≥3mm were measured and classified. The data were classified by the number of follicular waves per goat to test the hypothesis that temporal and morphological differences between the last follicular wave of an ovary, irrespective of ovulation, will affect the selection of the next ovulatory wave. The mean interovulatory interval was 20.7±1.0 days (mean±S.D.). Three to five waves per estrous cycle were observed and 61.3% (19/31) of cycles had fourwaves. In estrous cycles with fourwaves, the day of onset of the first, second, third and fourth wave was 1.4±1.0, 6.9±1.4, 11.6±1.8 and 16.8±1.6, respectively. No differences (P > 0.05) were found between the day of onset of the first and second waves for estrous cycles with three, four or five waves. However, the day of onset of the third and fourth waves occurred later when the number of waves per estrous cycle increased (P < 0.001). The duration of the interwave interval (time between the day of onset of two consecutive waves) was longer when the second wave was ovulatory. The length of the growth phase (2.4±0.9 days) and size (5.9±0.7 mm) of the dominant follicle in the second wave were lower (P < 0.01) than for the first wave (3.3±1.2 days and 6.6±0.9 mm, respectively) and the fifth wave (4.1±1.2 days and 7.5±1.0 mm, respectively). Within pairs of ovaries, the onset of the last wave occurred later (P < 0.05) and was less variable in ovulatory ovaries (day 16.8±1.4, n = 20) than in anovulatory ovaries (day 15.1±3.7, n = 20). The length of the growing phase was longer (P < 0.001) in the last waves of ovulatory ovaries (3.1±0.9 days) than in the last waves of anovulatory ovaries (1.7±0.8 days). These results support the hypothesis that the day of onset of the ovulatory wave is related to or, at least, conditioned by the luteolysis and the decrease in plasma progesterone. In summary, the estrous cycle of Serrana goats is characterized by sequential follicular wave growth with a great variability in their onset and duration, with the exception of the ovulatory wave. The temporal and morphological differences observed in the last wave of estrous cycle provide strong evidence for the role of progesterone in their regulation

Formation of Mobile Chromatin-Associated Nuclear Foci Containing HIV-1 Vpr and VPRBP Is Critical for the Induction of G2 Cell Cycle Arrest

HIV-1 Viral protein R (Vpr) induces a cell cycle arrest at the G2/M phase by activating the ATR DNA damage/stress checkpoint. Recently, we and several other groups showed that Vpr performs this activity by recruiting the DDB1-CUL4A (VPRBP) E3 ubiquitin ligase. While recruitment of this E3 ubiquitin ligase complex has been shown to be required for G2 arrest, the subcellular compartment where this complex forms and functionally acts is unknown. Herein, using immunofluorescence and confocal microscopy, we show that Vpr forms nuclear foci in several cell types including HeLa cells and primary CD4+ T-lymphocytes. These nuclear foci contain VPRBP and partially overlap with DNA repair foci components such as γ-H2AX, 53BP1 and RPA32. While treatment with the non-specific ATR inhibitor caffeine or depletion of VPRBP by siRNA did not inhibit formation of Vpr nuclear foci, mutations in the C-terminal domain of Vpr and cytoplasmic sequestration of Vpr by overexpression of Gag-Pol resulted in impaired formation of these nuclear structures and defective G2 arrest. Consistently, we observed that G2 arrest-competent sooty mangabey Vpr could form these foci but not its G2 arrest-defective paralog Vpx, suggesting that formation of Vpr nuclear foci represents a critical early event in the induction of G2 arrest. Indeed, we found that Vpr could associate to chromatin via its C-terminal domain and that it could form a complex with VPRBP on chromatin. Finally, analysis of Vpr nuclear foci by time-lapse microscopy showed that they were highly mobile and stable structures. Overall, our results suggest that Vpr recruits the DDB1-CUL4A (VPRBP) E3 ligase to these nuclear foci and uses these mobile structures to target a chromatin-bound cellular substrate for ubiquitination in order to induce DNA damage/replication stress, ultimately leading to ATR activation and G2 cell cycle arrest

Etat actuel des méthodes utilisées pour la transplantation embryonnaire chez la chèvre

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Seleção e criopreservação de embriões caprinos e ovinos

Chapitre 2 Mention d'édition : 1 ed.International audienc

Produção in vivo de embriões caprinos e ovinos

Chapitre 1 Mention d'édition : 1 ed.International audienc

Le point sur la production et le transfert d’embryons obtenus in vivo et in vitro chez la brebis et la chèvre

National audienceThis paper reviews the technical bases of in vivo and in vitro embryo production in sheep and goat. The current limitations of in vivo embryo production : the variability of response to the hormonal treatment, the fertilization failure in females showing a high ovulatory response, the importance of premature regressed corpus lutea in goat are described. The new prospects offered by ovum pick-up allowing multiple recoveries from the same female and in vitro embryo production are presented with their limiting steps and research priorities. The recent improvements of embryo transfer and embryo freezing technologies could be use for constitution of flocks without risks of disease transmission and will allow in the future larger propagation of valuable genes in small ruminants populations.Cet article décrit les bases des techniques de production in vivo et in vitro des embryons ovins et caprins. Malgré les améliorations apportées à la technique, les limites de la production d’embryons in vivo sont précisées : variabilité de la réponse au traitement hormonal, fécondation difficile des femelles fortement superovulées, importance de la régression prématurée des corps jaunes chez la chèvre. Les nouvelles perspectives offertes par les ponctions répétées des ovocytes chez une même femelle, suivies de la production des embryons in vitro, sont présentées avec leurs limites actuelles et les recherches à mettre en œuvre pour les dépasser. Les progrès récents des techniques de transfert et de congélation des embryons devraient permettre dans le futur une plus grande utilisation du transfert embryonnaire dans les programmes d’éradication d’épizooties et d’amélioration génétique des petits ruminants

Possibilidades atuais da transferencia de embrioes em caprinos

International audienc

Possibilidades atuais da transferencia de embrioes em caprinos

International audienc

Anticorps anti-PMSG - Moment d'apparition de l'oestrus et fertilité après insémination artificielle

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Etat actuel des méthodes utilisées pour la transplantation embryonnaire chez la chèvre

National audienc