玉米F_2群体中偏分离RFLP标记在染色体上的分布及原因分析

研究了利用玉米85个 DNA 限制性片段长度多态性(RFLP)标记在玉米自交系7922与5003杂交 F2群体中的分离。结果表明,8.33%的标记显著或极显著地偏离了预期的孟德尔比例而表现偏分离,发现了2个偏分离的染色体热点,即第1染色体上的 umc128-umc107和第3染色体上的 asg24-asg48,其偏分离形成的主要原因是存在配子体选择。     

Serum and Tissue Steroid Hormone Levels in Canine Mammary Tumours: Clinical and Prognostic Implications

Hormonal dependency of canine mammary tumours (CMT) has been studied over the last few decades. However, studies assessing the prognostic and predictive potential of serum and/or tissue steroid hormone levels are still scarce in CMT. To the best of our knowledge, this is the first report relating serum and tissue levels of steroid hormones and prognosis in dogs. Serum and tumour tissue from 45 female dogs with spontaneous CMT were included in the study. Moreover, serum and normal mammary tissue from 13 healthy female dogs were also included as controls. Steroid hormones were determined by competitive enzyme immunoassay. Overall, levels of steroid hormones in serum and tissue homogenates were significantly different between malignant and benign mammary tumours (p < 0.01), except for progesterone (P4) serum levels that revealed no statistical differences between groups. In malignant tumours, oestrone sulphate (SO4E1), dehydroepiandrosterone (DHEA), androstenedione (A4), testosterone (T) and P4 elevated tissue concentrations were significantly associated with tumour relapse and/or distant metastasis during follow‐up. A significant association was found between elevated tissue SO4E1 (p = 0.003), 17β‐oestradiol (E2) (p = 0.036), DHEA (p = 0.022), A4 (p = 0.001) and P4 (p = 0.013) concentrations and shorter disease‐free survival and overall survival in female dogs with malignant mammary tumours. The high levels of tissue steroids found in cases of poor prognosis open the possibility of additional new therapeutic approaches. Future clinical trials will be needed to clarify the usefulness of targeting steroid hormones in the treatment of this neoplastic disease.     

Evaluation of food protective property of five natural products using fresh-cut apple slice model

The present study evaluated the antioxidant (AA), antimicrobial and preservation effects of five plant derived natural products viz., Rosmarinic Acid (RA), p-Coumaric Acid (pCA), Trans-Cinnamic Acid (TCA), Hydroxyphenyllactic Acid (HPA) and Caffeic acid (CA) along with synthetic compounds (Ascorbic acid, gallic acid, citric acid and BHA) on fresh cut apple slices. Antimicrobial efficacy of these compounds against Bacillus licheniformis, Pseudomonas vulgaris, Shigella boydii, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli was found to be concentration dependent with the maximum inhibition observed at 500 microg mL(-1). A considerable AA potential of these compounds was observed in in vitro based assay system, with RA exhibiting significantly higher effect than the other compounds at 500 microg mL(-1). Furthermore the compounds at 500 microg mL(-1) significantly reduced the browning, maintained the acidic pH and restricted growth of L. monocytogenes even after 10 days of treatment. Ethanol accumulation in fresh cut apple slices increased significantly throughout the experimental period. Over all RA exhibited maximum effect in all the food preservation parameters studied suggesting that it has synchronized food protection effect and can be recommended as food additive.     

Solid‐Surface Vitrification and In‐Straw Dilution After Warming of In Vitro‐Produced Bovine Embryos

Three experiments were designed to test a solid‐surface vitrification system for bovine in vitro‐produced embryos and to develop a simple method of in‐straw dilution after warming, which can be potentially used for direct transfer in the field. Experiment 1 evaluated embryo survival rates (i.e. re‐expansion and hatching) after vitrification and warming in three different solutions: VS1 (20% ethylene glycol (EG) + 20% propanediol (PROH) + 0.25 m trehalose (Tr)), VS2 (20% EG + 1M Tr) or VS3 (30% EG + 0.75 m Tr). Re‐expansion and hatching rates were higher (p < 0.05) for embryos vitrified in VS3 (72.2 ± 1.9 and 58.2 ± 0.8) than VS1 (64.4 ± 0.9 and 37.2 ± 2.5) or VS2 (68.5 ± 1.5 and 49.6 ± 1.0; p < 0.05). Experiment 2 was designed to compare two methods of vitrification: glass micropipettes or solid surface, using the VS1 or VS3 solutions. No significant differences were detected between the two methods; but re‐expansion and hatching rates were higher (p < 0.05) with VS3 (73.5 ± 3.1 and 47.1 ± 2.1) than VS1 (63.3 ± 3.3 and 39.7 ± 2.8). In experiment 3, embryos were vitrified by solid surface in VS1 or VS3 solutions and cryoprotectants were diluted in‐straw after warming in a TCM 199, 0.25 m sucrose solution or holding media. Survival rates of embryos vitrified in VS3 did not differ between those exposed to 0.25 m sucrose (74.7 ± 1.3 and 57.2 ± 2.2) or holding (77.3 ± 1.4 and 58.0 ± 2.5) medium after warming; however, survival rates of embryos vitrified in VS1 were higher (p < 0.05) in those exposed to 0.25 m sucrose (67.7 ± 2.3 and 47.0 ± 1.7) than holding medium (54.5 ± 1.0 and 27.7 ± 3.1). In conclusion, solid‐surface vitrification using simplified EG‐based solutions and in‐straw dilution with holding media may be a practical alternative for cryopreservation and direct transfer of in vitro‐produced bovine embryos.     

Chemical composition and antioxidant property of holy basil (Ocimum sanctum L.) leaves, stems, and inflorescence and their in vitro callus cultures

In this study, the chemical constituents and antioxidant property of holy basil (Ocimum sanctum Linn.) field-grown plant parts (leaves, stems, and inflorescence) were compared with those of respective callus cultures induced from each explant in in vitro. The callus cultures were successfully initiated on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) (1 mg/L) combined with different concentrations (0.1-0.5 mg/L) of kinetin as plant growth regulators. The distribution of phenolic compounds in these extracts was analyzed using reverse phase high-performance liquid chromatography with reference standards. Interestingly, rosmarinic acid (RA) was found to be the predominant phenolic acid in all callus extracts in comparison with field-grown plant parts. In this study, the antioxidant activity of the extracts was evaluated with six different in vitro antioxidant-testing systems. Their activities of scavenging superoxide anion radicals, 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl radicals, hydrogen peroxide, chelating ferrous iron, and ferric ion reducing potential were assessed. The antioxidant activity was increased in all testing systems with increasing amounts of extract. However, at the same concentration, the callus extracts exhibited higher antioxidant activity in all of the testing systems than the extract obtained from field-grown plant parts. The data obtained from this study suggested the possibility of the isolation of a high content of RA from in vitro callus cultures rather than field-grown plant organs of holy basil.     

治疗奶牛乳腺炎的新药盐酸吡利霉素研究进展

综述了治疗奶牛乳腺炎的新药——盐酸吡利霉素最新研究进展.对其基本药学性质、药动、药效、毒性和残留等多方面进行了详细阐述.     

磷酸泰乐菌素颗粒剂生物效价测定方法的建立及验证

建立了磷酸泰乐菌素颗粒剂的生物效价测定方法，并对新建立的测定方法进行了验证，验证内容包括：方法对照试验、精密度试验、线性及线性范围试验、回收率试验。验证结果证明新方法能准确测定磷酸泰乐菌素颗粒剂的效价单位。