Effect of suckling intensity on human growth hormone binding, biochemical composition and histological characteristics of ovine mammary glands

Suckling both, or only one contralateral mammary gland during 15 days postpartum was utilized to study lactogenic hormone binding to mammary microsomal membranes and quantitative mammary morphology in ewes. Binding of radiolabeled human growth hormone was specific for lactogenic hormones. Non-radiolabeled human growth hormone, ovine and bovine prolactin and human placental lactogen effectively competed with radiolabeled human growth hormone for binding sites but ovine and bovine growth hormone were completely ineffective. Specific binding of radiolabeled human growth hormone to 600 μg of membrane protein averaged 23 ± 3% in all lactating glands. Neither days postpartum nor treatment of contralateral mammary glands substantially altered hormone binding in lactating glands. Specific human growth hormone binding (6 ± 0.5%) in non-suckled glands (15 days postpartum both udder halves) was significantly lower (P<0.01) than in lactating tissue but only a moderate and variable reduction in specific binding was measured in membranes from glands non-suckled for 15 days but contralateral to a suckled gland (14 ± 4%). Specific binding was approximately doubled in assays with 600 compared with 300 μg of membrane protein and the pattern of binding among variously suckled glands was not changed by treatment of membranes with 4 M MgCl₂ prior to assay. Most secretory cells from all lactating glands had rounded, basally displaced nuclei, apical fat globules, secretory vesicles and abundant densely stained basal cytoplasm (ergastoplasm). Alveolar lumenal area was maximal (50% of tissue area) and stromal tissue area was minimal. After 15 days of non-suckling (both udder halves) mammary cells were engorged with lipid, ergastoplasm was reduced and nuclei were irregularly shaped and randomly displaced compared with lactating tissue. In addition, lumenal area was reduced and stromal tissue more evident. Lack of suckling for 5 days had little apparent effect on mammary cytology. Like lactogenic hormone binding, mammary tissue morphology was only moderately altered by 15 days of non-suckling when the remaining gland was suckled. RNA concentration was lowest (2.1 ± 0.3 mg/g) in mammary tissue from ewes in which neither gland was suckled for 15 days postpartum but non-suckling interval had no significant effect when contralateral glands were suckled. DNA concentration was not significantly influenced by suckling treatments. Relative lactogenic hormone binding closely corresponded to changes in cytological and biochemical indices of secretory cell function.     

麦克兜兰在潮汕地区的引种表现及花期调控

本文通过对麦克兜兰在潮汕地区温室大棚的引种栽培管理，从光照、温湿度、肥水、病虫害管理及空调催花等方面对麦克兜兰进行研究。结果表明麦克兜兰能够较好地适应潮汕地区的温室栽培，通过空调催花可以实现春节前开花，达到年宵花生产目的，为麦克兜兰在潮汕地区进行温室规模化生产提供参考。     

北京市农产品加工业出口竞争力的分析——基于波特的“钻石模型”

利用波特的"钻石模型"对北京市农产品加工业出口的条件从要素资源、需求状况、支持性产业和相关性产业、企业战略结构和竞争、机遇与市场机会等方面进行分析,结论表明,北京市发展农产品加工业出口的高级要素方面具有优势,但郊区的基础设施并不乐观;北京市郊区发展农产品加工业出口在相关产业方面具有一定优势,而支持性产业方面则面临一些制约;北京市发展农产品加工业出口还需政府的支持.     

戈尔曼情商理论与和谐图书馆的构建

在党中央提出“以人为本”构建和谐社会新理念的大背景下，高校图书馆作为一个履行高校教育、情报传递和研究支持等多重功能的机构，如何更好地适应时代的要求，提升图书馆的服务水平，建设和谐、包容、愉悦的图书馆人际氛围？美国《纽约时报》专栏作家丹尼尔·戈尔曼博士为我们带来了“情绪商数”理论，从表达个人、适应别人、如何调控情绪几个方面，为构建和谐图书馆提供了理论指导。笔者也从以上方面，表述了自己的想法。     

迈克尔加成反应预测冬凌草活性成分及其乙酰化产物抗肿瘤活性

为了快速、简便地评价冬凌草(Isodon rubescens(Hemsley) H. Hara)活性成分的抗肿瘤活性,以冬凌草活性成分冬凌草甲素和冬凌草乙素及其乙酰化产物与对硝基苯甲酰乙酸乙酯( ENBA)进行迈克尔加成反应,以反应动力学得出迈克尔加成反应的反应活性,首次以反应活性预测了对冬凌草甲素(1)、冬凌草乙素(2)、1,14-二乙酰基冬凌草甲素(1a)和1,6-二乙酰基冬凌草乙素(2a)4个对映-贝壳杉烯的抗肿瘤活性。结果表明：4种活性成分的迈克尔加成反应均符合二级动力学方程,反应活性1>1a>2>2a,根据阿伦尼乌斯公式,测得冬凌草甲素活化能(Ea)为(38.7±5.8) kJ/mol,冬凌草乙素Ea 为(46.8±7.1) kJ/mol。采用1 H NMR和13 C NMR等波谱技术鉴定冬凌草甲素与ENBA经迈克尔加成反应得到的新化合物为1α,6β,7β,14β-四羟基-7α,20-环氧-17-(2-(3-(4-硝基苯基))-3-氧-丙酸乙酯)-对映贝壳杉烷-15-酮,命名为nitrobenoridonin (1b)。4个对映-贝壳杉烯具有较强的体外抗肿瘤活性,经测定它们的抗肿瘤活性大小依次为1>1a>2>2a,与其迈克尔加成反应活性排序一致,表明迈克尔加成反应活性与抗肿瘤活性之间存在较好的相关性,可以通过测定迈克尔加成反应活性预测对映-贝壳杉烯的抗肿瘤活性。