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Mechanistic target of rapamycin is activated in bovine granulosa cells after LH surge but is not essential for ovulation
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PRA da Rosa AMP Dau MP De Cesaro JT dos Santos BG Gasperin R Duggavathi V Bordignon PBD Gonçalves 《Reproduction in domestic animals》2016,51(5):766-773
The LH surge induces functional and morphological changes in granulosa cells. Mechanistic target of rapamycin (mTOR) is an integrator of signalling pathways in multiple cell types. We hypothesized that mTOR kinase activity integrates and modulates molecular pathways induced by LH in granulosa cells during the preovulatory period. Cows were ovariectomized and granulosa cells collected at 0, 3, 6, 12 and 24 hr after GnRH injection. While RHEB mRNA levels increased at 3 and 6 hr, returning to basal levels by 12 hr after GnRH treatment, RHOA mRNA levels increased at 6 hr and remained high thereafter. Western blot analyses revealed increased S6K phosphorylation at 3 and 6 hr after GnRH injection. Similarly, mRNA levels of ERK1/2, STAR and EGR‐1 were higher 3 hr after GnRH treatment. Rapamycin treatment inhibited mTOR activity and increased AKT activity, but did not alter ERK1/2 phosphorylation and EGR1 protein levels in cultured bovine granulosa cells. Rapamycin also inhibited LH‐induced increase in EREG mRNA abundance in granulosa cells in vitro. However, intrafollicular injection of rapamycin did not suppress ovulation. These findings suggest that mTOR is involved in the control of EREG expression in cattle, which may be triggered by LH surge stimulating RHEB and S6K activity. 相似文献
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Serological response to Actinobacillus pleuropneumoniae serovar 7 infection in a commercial pig herd
IA GARDNER JT BOSSɆ RF SHELDRAKE† S ROSENDAL† RP JOHNSON§ 《Australian veterinary journal》1991,68(11):349-352
Serological responses to Actinobacillus pleuropneumoniae serovar 7 infection were monitored by enzyme-linked immunosorbent assay in a cohort of 66 pigs between weaning and market. Antibody concentrations were high (63/65 seropositive) at 4 weeks of age but declined to low levels from 8 to 12 weeks. Mean antibody concentrations rose significantly (p less than 0.001) between 12 and 23 weeks. Between 8 and 23 weeks of age, 33 (51.5%) of 64 surviving pigs seroconverted to A pleuropneumoniae serovar 7. Peak antibody concentrations in the seroconverting pigs usually (28/33) occurred at 23 weeks. Seroconversion to A pleuropneumoniae during the grower/finisher phase was not significantly associated (p greater than 0.05) with passive antibody concentrations at 4 weeks of age, lack of vaccination against Mycoplasma hyopneumoniae, or weaning weight. Pleuropneumonic lesions were evident at slaughter in 4 (6.3%) of 64 pigs. A pleuropneumoniae serovar 7 was isolated from 2 of 4 lungs with pleuropneumonia and from another lung with lesions considered typical of enzootic pneumonia. 相似文献
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In a pen feeding trial fresh Echium plantagineum was fed as the sole diet to crossbred sheep with or without a history of previous access to the plant. Control groups received a diet of lucerne chaff and oats. During the trial, sheep on the Echium diet lost weight and deaths occurred with histological evidence of excessive copper accumulation, usually accompanied by pyrrolizidine alkaloid damage, in the liver and biochemical evidence of liver toxicity. It is concluded that E. plantagineum alone is not a suitable fodder for sheep and can be toxic due to its pyrrolizidine alkaloid content and high copper to molybdenum ratio. 相似文献
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There is increasing evidence that fish gain energetic benefits from the hydrodynamic interactions when they swim in a school. The most recent indications of such benefits are a lower tail (or fin) beat at the back of a school and reduced oxygen consumption in schooling fish versus solitary ones. How such advantages may arise is poorly understood. Current hydrodynamic theories concern either fish swimming side by side or in a diamond configuration and they largely ignore effects of viscosity and interactions among wakes and individuals. In reality, however, hydrodynamic effects are complex and fish swim in many configurations. Since these hydrodynamic effects are difficult to study empirically, we investigate them in a computer model by incorporating viscosity and interactions among wakes and with individuals. We compare swimming efficiency of model fish (based on shapes of mullets of 126 mm) travelling solitarily and in schools at several interindividual distances in four different configurations (diamond, rectangular, phalanx and line). We show that these fish always swim more efficiently in a school than alone (except in a dense phalanx). We indicate how this efficiency may emerge from several kinds of interactions between wakes and individuals. As individuals in our simulations are not even intending to exploit the wake, gains in efficiency are obtained more easily than previously thought. 相似文献
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An unexpected three-stage melting transition has been observed in two-dimensional (2D) free-standing liquid-crystal films by in situ electron-diffraction and optical-reflectivity measurements. These data suggest the existence of two phases between the 2D solid and liquid: a hexatic phase and, at a higher temperature, an intermediate liquid phase with hexatic-like positional correlations ( approximately 40 angstroms) but no long-range orientational order. Previous high-resolution heat-capacity measurements have revealed a divergent-like anomaly at the hexatic-liquid transition that sharply contradicts the predictions of 2D melting theories. The observation of an intermediate isotropic phase may alter our understanding of 2D melting and lead to reconciliation between current experiments and theories. 相似文献
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Objectives To characterise the changes caused to sheep skin by deep dermal and subcutaneous injections of sodium lauryl sulfate (SLS) and describe the subsequent healing process. Procedure On 6 sheep 20 small areas of skin were each given deep dermal and subcutaneous injections of 0.2 mL of 7% SLS. Biopsies were collected at intervals up to 28 days after treatment and the histological changes in each of the treated skin samples were assessed and graded. Results There was no evidence of alterations in behaviour, weight gain or appetite of the sheep following the injections. Initial swelling of the treated site subsided by day 14, leaving a firm, slightly raised crust. At day 21, the treated area was depressed and covered by a scab, which sloughed completely by day 28. There was necrosis of the subcutis and deep dermis 2 min after treatment, followed by inflammation, fibroplasia, angiogenesis and tissue remodelling. Conclusion Injection of SLS caused almost immediate local necrosis followed by eschar formation, sloughing and scarring of treated skin. Deep dermal and subcutaneous SLS is potentially useful as a chemical alternative to mulesing. 相似文献
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AW PHILBEY JRW GLASTONBURY JT ROTHWELL IJ LINKS JE SEARSON 《Australian veterinary journal》1991,68(12):387-390
Histophilus ovis was isolated from 29 sheep in 20 flocks and 2 artificial insemination (AI) centres in southern New South Wales from 1984 to 1990. The clinical and pathological findings were consistent with previous reports and included polyarthritis (7 flocks), epididymo-orchitis (5), meningoencephalitis (3), pneumonia (3), septicaemia (2), mastitis (1) and metritis (1). Six sheep had meningoencephalitis, a syndrome not previously associated with H ovis infection in sheep, which was similar pathologically to thromboembolic meningoencephalitis in cattle, caused by the related organism, Haemophilus somnus. H ovis was isolated from the semen of 12-month-old rams in a flock that had polyarthritis due to H ovis, in 4-month-old ram lambs and from the uterus of a ewe in a flock that had sporadic cases of H ovis septicaemia. 相似文献