Involvement of the ERK1/2 MAPK pathway in insulin-induced S6K1 activation in avian cells     

Duchêne S  Audouin E  Crochet S  Duclos MJ  Dupont J  Tesseraud S 《Domestic animal endocrinology》2008,34(1):63-73

In mammals, insulin regulates S6K1, a key enzyme involved in the control of protein synthesis, via the well-documented phosphoinositide-3'kinase (PI3K) pathway. Conversely, S6K1 is activated by insulin in avian muscle despite the relative insulin insensitivity of the PI3K pathway in this tissue. Mitogen-activated protein kinase (MAPK) cascade is another insulin sensitive pathway. The aim of this study was to explore the potential involvement of the ERK1/2 MAPK pathway in the control of p70 S6 kinase (S6K1) in avian species. Firstly, we characterized ERK1/2 MAPK in various chicken tissues. ERK2 was the only isoform detected in avian species whatever the tissue studied. We also showed that ERK2 is activated in vivo by insulin in chicken muscle. The regulation and the role of ERK2 in insulin signaling were next investigated in chicken hepatoma cells (LMH) and primary myoblasts. Insulin stimulation led to ERK2 and S6K1 phosphorylation, and concomitantly increased kinase activity. U0126, an inhibitor of the ERK MAPK pathway, completely abolished insulin-induced S6K1 phosphorylation and activity in chicken myoblasts, whereas its effect was only partial in LMH cells. In conclusion, these results show that ERK1/2 MAPK is involved in the control of S6K1 by insulin in chicken cells, particularly myoblasts.  相似文献   

IGF-1 receptor signaling pathways and effects of AMPK activation on IGF-1-induced progesterone secretion in hen granulosa cells     

Tosca L  Chabrolle C  Crochet S  Tesseraud S  Dupont J 《Domestic animal endocrinology》2008,34(2):204-216

IGF-1 plays a key role in the proliferation and differentiation of granulosa cells. However, the molecular mechanism of IGF-1 action in avian granulosa cells during follicle maturation is unclear. Here, we first studied IGF-1 receptor (IGF-1R) expression, IGF-1-induced progesterone production and some IGF-1R signaling pathways in granulosa cells from different follicles. IGF-1R (mRNA and protein) was higher in fresh or cultured granulosa cells from the largest follicles (F1 or F2) than in those from smaller follicles (F3 or F4). In vitro, IGF-1 treatment (10(-8)M, 36h) increased progesterone secretion by four-fold in mixed F3 and F4 (F3/4) granulosa cells and by 1.5-fold in F1 granulosa cells. IGF-1 (10(-8)M, 30min)-induced increases in tyrosine phosphorylation of IGF-1R beta subunit and phosphorylation of ERK were higher in F1 than in F3/4 granulosa cells. Interestingly, IGF-1 stimulation (10(-8)M, 10min) decreased the level of AMPK Thr172 phosphorylation in F1 and F3/4 granulosa cells. We have recently showed that AMPK (AMP-activated protein kinase) is a protein kinase involved in the steroidogenesis in chicken granulosa cells. We then studied the effects of AMPK activation by AICAR (5-aminoimidazole-4-carboxamide ribonucleoside), an activator of AMPK, on IGF-1-induced progesterone secretion by F3/4 and F1 granulosa cells. AICAR treatment (1mM, 36h) increased IGF-1-induced progesterone secretion, StAR protein levels and decreased ERK phosphorylation in F1 granulosa cells. Opposite data were observed in F3/4 granulosa cells. Adenovirus-mediated expression of dominant negative AMPK totally reversed the effects of AICAR on IGF-1-induced progesterone secretion, StAR protein production and ERK phosphorylation in both F3/4 and F1 granulosa cells. Thus, a variation of energy metabolism through AMPK activation could modulate differently IGF-1-induced progesterone production in F1 and F3/4 granulosa cells.  相似文献   

Testis-specific histone variants H2AL1/2 rapidly disappear from paternal heterochromatin after fertilization     

Wu F  Caron C  De Robertis C  Khochbin S  Rousseaux S 《The Journal of reproduction and development》2008,54(6):413-417

Before fertilization, the genome packaging of male and female gametes is very different. Indeed, whereas the female haploid genome is associated with histones in a somatic-like chromatin structure, most of the male genome is tightly bound to protamines. However, it has recently been demonstrated that the pericentric heterochromatin regions of the male genome are associated with specific H2A-like histone variants, named H2AL1 and H2AL2, suggesting a heterogeneous organization. The fate and role of the sex-specific genome packaging transmitted by germinal cells to the embryo are not well understood. The aim of the present study was to follow reprogramming of the parental genomes in early embryos after in vivo fertilization. We show here that two typical epigenetic markers, trimethylated lysine 9 of histone H3 (TriMethylH3K9) and acetylated H4, are asymmetrically distributed between the parental genomes in one-cell mouse embryos, confirming data from embryos obtained after intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF). Indeed, whereas the maternal genome is highly enriched with trimethylH3K9, this mark is not detected in the paternal genome. On the contrary, histone H4 incorporated in the paternal genome is highly acetylated at an early stage, while in the maternal pronucleus, the level of acetylated H4 remains low in early one-cell embryos and becomes enriched at a later stage. Moreover, our results suggest a very quick disappearance of histone H2A variants H2AL1 and H2Al2 from the paternal pericentric heterochromatin regions after sperm-egg fusion.  相似文献   

Fluid therapy in patients with pulmonary disease.     

Sophie Adamantos  Dez Hughes 《Veterinary Clinics of North America: Small Animal Practice》2008,38(3):719-25, xiv

Fluid therapy in patients with pulmonary disease is challenging. Although a single set of rules cannot be applied to every patient, the following guidelines can be used when managing patients with pulmonary disease. Euvolemic patients with adequate tissue perfusion should be given sufficient isotonic fluid to balance insensible losses. If severe pulmonary compromise is present, cessation of all fluid therapy may be considered if the patient is able to match its losses by voluntary intake. In hypovolemic or hypotensive patients, small boluses of isotonic crystalloids or colloids should be given to restore perfusion, avoiding rates of more than 30 mL/kg an hour for isotonic crystalloids. If perfusion is not restored by adequate volume resuscitation, vasopressors or positive inotropes should be administered to prevent fluid overload and deterioration in pulmonary function.  相似文献   

Sentinel lymph node mapping by near‐infrared fluorescence imaging and contrast‐enhanced ultrasound in healthy dogs     

Sophie Favril  Emmelie Stock  Sophie Hernot  Myriam Hesta  Ingeborgh Polis  Katrien Vanderperren  Hilde de Rooster 《Veterinary and comparative oncology》2019,17(1):89-98

Sentinel lymph node (SLN) mapping is a valuable and crucial diagnostic procedure in staging malignancies. We compared two non‐invasive techniques, near‐infrared (NIR) fluorescence imaging and contrast‐enhanced ultrasound (CEUS), to identify the SLNs in three superficial anatomical regions in an animal model. Six healthy laboratory dogs were included in a proof‐of‐concept trial. A NIR fluorescent dye (Indocyanine Green) and microbubbles (Sonovue) were consecutively injected subdermally in the Inguinal, axillary and popliteal region to map the SLNs. Transcutaneous NIR fluorescence imaging identified SLNs in 17 out of a total of 18 occasions. CEUS identified SLNs in all regions (18/18). Whereas NIR fluorescence imaging performed better in the visualization of the afferent lymphatic tract, CEUS demonstrated different filling patterns of the SLNs, a feature potentially critical for the concept of SLN mapping in cancer patients. Both NIR fluorescence imaging and CEUS are safe, non‐invasive, practical and accurate methods to perform real‐time transcutaneous SLN mapping with potential in a clinical setting.  相似文献   

Comparison of hydroalcoholic rubbing and conventional chlorhexidine scrubbing for aseptic skin preparation in dogs     

Erik Asimus  Sophie Palierne  Margaux Blondel  Valentine Pollet  Aude Ferran  Alain Bousquet‐Melou  Jean‐Franois Rousselot  Andr Autefage 《Veterinary surgery : VS》2019,48(8):1466-1472

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Mycobacterium nebraskense infection in a dog in Switzerland with disseminated skin lesions     

Katrin Timm  Monika Welle  Ute Friedel  Danille Gunn‐Moore  Sophie Peterhans 《Veterinary dermatology》2019,30(3):262-e80

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Effect of sedation with butorphanol on variables pertaining to the ophthalmic examination in dogs          下载免费PDF全文

Jean‐Yves Douet  Alain Regnier  Agnès Dongay  Sophie Jugant  Géraldine Jourdan  Didier Concordet 《Veterinary ophthalmology》2018,21(5):452-458

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Accumulation of acaricide resistance mechanisms in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) populations from New Caledonia Island     

Chevillon C  Ducornez S  de Meeûs T  Koffi BB  Gaïa H  Delathière JM  Barré N 《Veterinary parasitology》2007,147(3-4):276-288

Rhipicephalus (Boophilus) microplus has been pesticide-controlled for several decades in the pacific island of New Caledonia. Since 1996, pesticide-control has been based on either deltamethrin (Butox) or amitraz (Taktic) in herds harbouring deltamethrin-resistant ticks. In this island, the first R. microplus deltamethrin- and amitraz-resistances were detected in 1992 and 2003, respectively. Using LPT bioassays, we have undertaken to update data regarding the geographical distribution and the physiological diversity likely to be involved in these resistances. We confirmed that after 17 years of intensive use of deltamethrin, several resistances of moderate levels (<30-fold) have evolved and/or diffused in any part of the island. We also evidenced that amitraz-resistant phenotypes have recently evolved in diverse western tick populations, although none has reached fixation in any tick population yet. According to synergists bioassays, the physiological changes involved in amitraz-resistance in New Caledonia would involve target modification and detoxifying P450 cytochrom oxydase(s). It may also involve detoxifying esterase(s) although this later point will need confirmation on samples bearing higher frequency of resistant phenotypes. Results are discussed with regard to the local evolutionary dynamics of resistance.  相似文献   

RhizoTubes as a new tool for high throughput imaging of plant root development and architecture: test,comparison with pot grown plants and validation     

Christian?Jeudy  Marielle?Adrian  Christophe?Baussard  Céline?Bernard  Eric?Bernaud  Virginie?Bourion  Hughes?Busset  Lloren??Cabrera-Bosquet  Frédéric?Cointault  Simeng?Han  Mickael?Lamboeuf  Delphine?Moreau  Barbara?Pivato  Marion?Prudent  Sophie?Trouvelot  Hoai?Nam?Truong  Vanessa?Vernoud  Anne-Sophie?Voisin  Daniel?Wipf  Christophe?SalonEmail author 《Plant methods》2016,12(1):31

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