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排序方式: 共有370条查询结果,搜索用时 109 毫秒
1.
H J Leese P G Humpherson K Hardy M A Hooper R M Winston A H Handyside 《Journal of reproduction and fertility》1991,91(1):197-202
The profiles of hypoxanthine guanine phosphoribosyl transferase (HGPRT) and adenine phosphoribosyl transferase (APRT) activities were examined in normally fertilized human embryos developing at the normal rate in vitro between the 2-4-cell stage on Day 2 and the blastocyst stage on Day 6 after insemination. The activities of both enzymes were assayed simultaneously in extracts of single embryos by measuring the rate of production of the reaction products, inosine monophosphate (IMP) and adenine monophosphate (AMP), separated by high-performance liquid chromatography (HPLC). The activity profiles of the two enzymes over this period showed marked differences. The activity of HGPRT, coded by the X chromosome, increased between Days 2 and 4 (P less than 0.01) but declined sharply by Day 6 (P less than 0.001), whereas autosome-coded APRT activity remained low between Days 2 and 5, but increased on Day 6 (P less than 0.05). The profile of HGPRT activity may reflect a combination of decreasing levels of maternal enzyme inherited from the oocyte and the initiation of embryonic gene expression followed by X inactivation at the blastocyst stage on Day 6. 相似文献
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Ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 1.1.39) (RuBPCase) was quantified using polyacrylamide-gel electrophoresis in whole 9-d-old first leaves of 14 genotypes of Triticum, and cellular RuBPCase levels calculated. Diploids, tetraploids and hexaploids were analysed and it was confirmed that the RuBPCase level per cell is closely related to ploidy in wheat. Inter-genotypic variation in RuBPCase levels per cell and per leaf were surveyed. It was found that the interactions between leaf size, cell size and RuBPCase levels result in small variations in RuBPCase levels per unit leaf area between genotypes.Abbreviation RuBPCase
ribulose-1,5-bisphosphate carboxylase/oxygenase 相似文献
3.
The economic decisions taken by family doctors in one family practitioner area in the north of England were examined. There was evidence of a differential response to professional and economic incentives by a group of "high investing" practices. On five indicators of improvement in practice 32% of the practices accounted for 71% of the positive scores. Nearly all the high investing practices were in affluent areas; they were on average larger and had younger partners than the other practices. The high investing practices also faced more financial problems. There was evidence that older doctors with long lists of patients had a different strategy of income maximization. Innovation in primary care is not determined by attitude alone but also by objective factors such as age, location, and size of the practice. 相似文献
4.
Maurizio Varnier Patrizio Sarto Diego Martines Liliana Lora Francesco Carmignoto Graham Peter Leese Remo Naccarato 《European journal of applied physiology and occupational physiology》1994,69(1):26-31
The aim of this study was to investigate whether, when muscle glycogen is reduced, a pre-exercise infusion of branched-chain amino acids (BCAA) modifies exercise performance or the metabolic and respiratory responses to incremental exercise. Six moderately trained volunteers took part in the following protocol on two occasions. On day 1, at 9 a.m. in the postabsorptive state, they performed a graded incremental exercise (increases of 35 W every 4 min) to exhaustion (Ex-1). A meal of 1,000 kcal (4,200 kJ; 60% protein, 40% fat) was consumed at 12 p.m. No food was then allowed until the end of the experiment (20–21 h later). A 90-min period of exercise at alternating high and moderate intensities, designed to deplete muscle glycogen, was performed between 6 p.m. and 7.30 p.m. The morning after (day 2), the subjects randomly received either a mixed solution of BCAA (260 mg × kg–1 × h–1 for 70 min), or saline. They then repeated the graded incremental exercise to exhaustion (Ex-2). Metabolic and respiratory measurements suggested a muscle glycogen-depleted state had been achieved. No significant differences were observed in total work performed, maximal oxygen uptake or plasma ammonia, alanine, and blood pyruvate concentrations in the two treatments. After BCAA infusion, higher blood lactate concentrations were observed at maximal power output in comparison with those during saline [BCAA 4.97 (SEM 0.41) mmol × l–1, Saline 3.88 (SEM 0.47) mmol × l–1,P < 0.05]. In summary, in conditions of reduced muscle glycogen content, after a short period of fasting, BCAA infusion had no significant effect on the total work that could be performed during a graded incremental exercise. 相似文献
5.
The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
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AB Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(4):261-268
Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight. 相似文献
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