Effect of Rhizobium leguminosarum 252 agglutinins on the activity of some plant cell enzymes]

The incubation of pea seedling roots with the surface agglutinins R1 and R2 of Rhizobium leguminosarum 252 brought about an increase in the activity of proteases, beta-glucosidase, and, especially, succinate dehydrogenase in the roots. The data presented show that rhizobial agglutinins play an important part in the formation and functioning of legume-rhizobial associations.     

大鼠脑缺血再灌注后血清中血管内皮生长因子与神经元凋亡的研究

目的：通过检测SD大鼠脑缺血再灌注模型血清中血管内皮生长因子（VEGF）与神经元凋亡动态表迭变化的关系,以探讨两者之间的相关性。方法：将40只大鼠随机分为8组：对照组、假手术组和脑缺血30min再灌注12h组、1d组、3d组、5d组、7d组、及14d组,每组5只。采用ELISA双抗夹心法检测大鼠血清中血管内皮生长因子、原位细胞凋亡TUNEL法检测脑组织中的凋亡神经细胞数。结果：再灌注12h、1d、3d、5d、7d及14d大鼠血清VEGF表达和凋亡神经元百分比的变化均为负相关性（均为P〈0．05）。结论：在脑缺血再灌注大鼠模型中,缺血诱导使VEGF的表达发生变化,VEGF通过直接或间接的途径抑制神经元凋亡。     

昆虫弦音器及其声音感受分子机制

弦音器是昆虫类特有的一种机械感受器,亦称弦音感受器或剑梢感受器。它主要具有感知外界声压和体内肌肉运动的听觉功能,研究弦音器的机能结构对揭秘昆虫听觉的神经机制有重要的科学意义。本文从弦音器多样性和进化入手,重点综述了弦音器的微细结构、基因功能定位、声音感受分子机制及其声压增幅分子生物物理学原理,为昆虫听觉仿生学的研究提供了理论依据。     

昆虫弦音器及其声音感受分子机制

弦音器是昆虫类特有的一种机械感受器,亦称弦音感受器或剑梢感受器。它主要具有感知外界声压和体内肌肉运动的听觉功能,研究弦音器的机能结构对揭秘昆虫听觉的神经机制有重要的科学意义。本文从弦音器多样性和进化入手,重点综述了弦音器的微细结构、基因功能定位、声音感受分子机制及其声压增幅分子生物物理学原理,为昆虫听觉仿生学的研究提供了理论依据。     

Multilevel regulation of steroid synthesis and metabolism in the bovine placenta

Steroid hormones play critical roles in almost all physiological processes in male and female reproduction. In a normal pregnancy, the concentrations of steroid hormones in maternal and foetal blood vary with gestation in response to changing needs. The placenta plays a central role in producing the appropriate steroids to support the pregnancy by coordinating its own steroidogenic activity with that of the corpus luteum and responding to foetal signals. Although much is known about the steroidogenic potential of the bovine placenta, far less is known about how the placenta integrates the synthesis of steroids with their subsequent metabolism and clearance to achieve appropriate local and peripheral concentrations of steroids in maternal and foetal blood at each stage of gestation. This review focuses on the current knowledge of the temporal and spatial regulation and compartmentalization of the biochemical pathways by which potent steroid hormones are synthesized and metabolized in the bovine placenta. The aim is to increase our understanding of how the balance of synthesis and metabolism determines placental steroid output as it changes with development and differentiation, and how this is regulated in response to the variations in the foetal signals and luteal secretory activity. The review highlights knowledge gaps and suggests that mathematical modelling can help understand the effect of different levels of regulation on the steroidogenic output of an organ, such as the bovine placenta.     

鸡PPARγ基因的表达特性及其对脂肪细胞增殖分化的影响

为分析鸡PPARγ基因的组织表达特性及其在脂肪细胞增殖和分化过程中的功能,文章以东北农业大学高、低腹脂双向选择品系肉鸡为实验材料,利用Western blotting方法,检测PPARγ基因的组织表达特性及其在高、低脂系肉鸡腹部脂肪组织间的表达差异;采用RNAi技术,在鸡原代脂肪细胞中抑制PPARγ基因的表达后,通过MTT和油红O提取比色的方法,研究鸡PPARγ基因对脂肪细胞增殖和分化的调控作用;利用Real-timePCR和Western blotting技术,分析PPARγ基因表达下调后,其他脂肪细胞分化转录因子以及与脂肪细胞分化相关的重要基因的表达变化情况。结果表明,PPARγ基因在7周龄高脂系肉鸡腹部脂肪组织、肌胃、脾脏、肾脏组织中表达量较高,在心脏中表达量较低,在肝脏、胸肌、腿肌、十二指肠中未检测到表达信号;与高脂系相比,PPARγ基因在5和7周龄低脂系肉鸡腹部脂肪组织中的表达量较低(P<0.05);PPARγ基因的表达量下降后,鸡脂肪细胞的增殖能力增强,分化能力减弱;同时,C/EBPα、SREBP1、A-FABP、Perilipin1、LPL、IGFBP-2基因的表达量均下降(P<0.05)。由此可见,PPARγ基因的表达可能与肉鸡腹部脂肪的沉积有一定的关系,该基因可能是调控鸡脂肪细胞增殖与分化的关键因子。     

Sustained release of the antitumor drug paclitaxel from poly(3-hydroxybutyrate)-based microspheres

The development of sustained release formulations based on biodegradable polymers is a promising trend in modern pharmacology. Polyhydroxyalkanoates (PHA) attract increasing attention due to their biodegradability and high biocompatibility, which make them suitable for the development of novel drug dosage forms. We have produced poly(3-hydroxybutyrate) (PHB)-based microspheres loaded with the antitumor drug paclitaxel and investigated morphology, drug release kinetics and the effect of these microspheres on tumor cells in vitro. The data on the kinetics of drug release, biocompatibility and biological activity of the biopolymer microspheres in vitro have demonstrated that the studied system of prolonged drug release had lower toxicity and higher efficiency compared to the traditional dosage forms of paclitaxel.     

紫毛香茶菜中的黄酮类化合物

从紫毛香茶菜（Isodon enanderianus)的茎叶提取物中分离到7个黄酮类化合物,经波谱分析鉴定,其中一个为新的黄酮甙,即5-羟基-6,7,4-三甲氧基黄酮-8-O-β-D-葡萄糖甙（1）;其它6个已知的黄酮类化合物分别为芫花素（genkwanin,2)、滨蓟素（cirsimar-tin,3)、胡麻素（pedalitin,4)、鼬瓣花亭（ladanetin,5)、isothymusin-8-O-β-D-glucoside（6）和槲皮甙（quercitrin,7)。