The Molecular Mechanisms of Protective Role of Se on the G<Subscript>2</Subscript>/M Phase Arrest of Jejunum Caused by AFB<Subscript>1</Subscript>

Aflatoxin B₁ (AFB₁) is the most toxic among the mycotoxins and causes detrimental health effects on human and animals. Selenium (Se) plays an important role in chemopreventive, antioxidant, anticarcinogen, and detoxification and involved in cell cycle regulation. The aim of this study was to explore the molecular mechanisms of selenium involved in inhibition of G₂/M cell cycle arrest of broiler’s jejunum. A total of 240 one-day-old healthy Cobb broilers were randomly divided into four groups and fed with basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se (+Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se group) for 21 days, respectively. The histological observation and morphological analysis revealed that 0.4 mg/kg Se prevented the AFB₁-associated lesions of jejunum including the shedding of the apical region of villi, the decreased villus height, and villus height/crypt ratio. The cell cycle analysis by flow cytometry showed that 0.4 mg/kg Se ameliorated the AFB₁-induced G₂/M phase arrest in jejunal cells. Moreover, the expressions of ATM, Chk2, p53, Mdm2, p21, PCNA, Cdc25, cyclin B, and Cdc2 analyzed by immunohistochemistry and qRT-PCR demonstrated that 0.4 mg/kg Se restored these parameters to be close to those in the control group. In conclusion, Se promoted cell cycle recovery from the AFB₁-induced G₂/M phase arrest by the molecular regulation of ATM pathway in the jejunum of broilers. The outcomes from the present study may lead to a better understanding of the nature of selenium’s essentiality and its protective roles against AFB₁.     

MicroRNAs and their role in viral infection

Recently, a class of about 22 nucleotides (nt) small RNA has been discovered in many eukaryotes, termed microRNAs (miRNAs), which have a variety of functions. Many recent findings have demonstrated that viruses can also encode their own miRNAs. Meanwhile, other findings reveal a relationship between host miRNA and viral infection. These findings suggest a tight relationship between host and viral infection via miRNA pathway. This article introduces the miRNAs encoded by viruses and reviews the advances of the interaction of the mammalian host miRNAs and viral infection.     

后倾座椅与GZ-2抗荷服综合抗荷性能测定

目的 :探讨后倾座椅与GZ 2抗荷服的综合抗荷性能。方法 :在离心机上 ( +Gz增长率为 3G/s)先测出 6名受试者采用 13°座椅时的基础 +Gz耐力 ,然后测定受试者采用 13°座椅、并穿GZ 2抗荷服充气时的 +Gz耐力 ,再测定受试者采用 45°后倾座椅、并穿GZ 2抗荷服充气时的 +Gz耐力 ,其与基础 +Gz耐力之差 ,即为 45°座椅与GZ 2抗荷服的综合抗荷性能。结果 :受试者采用 13°座椅、穿GZ 2时的抗荷性能为 3 .0 6G ,采用 45°座椅、穿GZ 2时的抗荷性能为 4.13G ,抗荷性能比前者高出 1.0 6G。结论 :后倾座椅 (椅背角为 45°)可大幅度提高人体 +Gz耐力     

Antioxidant Activity and α-Glucosidase Inhibitory Activities of the Polycondensate of Catechin with Glyoxylic Acid

In order to investigate polymeric flavonoids, the polycondensate of catechin with glyoxylic acid (PCG) was prepared and its chemically antioxidant, cellular antioxidant (CAA) and α-glucosidase inhibitory activities were evaluated. The DPPH and ABTS radical scavenging activities and antiproliferative effect of PCG were lower than those of catechin, while PCG had higher CAA activity than catechin. In addition, PCG had very high α-glucosidase inhibitory activities (IC₅₀ value, 2.59 μg/mL) in comparison to catechin (IC₅₀ value, 239.27 μg/mL). Inhibition kinetics suggested that both PCG and catechin demonstrated a mixture of noncompetitive and anticompetitive inhibition. The enhanced CAA and α-glucosidase inhibitor activities of PCG could be due to catechin polymerization enhancing the binding capacity to the cellular membrane and enzymes.     

Systematic Analysis of Absorbed Anti-Inflammatory Constituents and Metabolites of Sarcandra glabra in Rat Plasma Using Ultra-High-Pressure Liquid Chromatography Coupled with Linear Trap Quadrupole Orbitrap Mass Spectrometry

Ultra-high-pressure liquid chromatography (UHPLC) was coupled with linear ion trap quadrupole Orbitrap mass spectrometry (LTQ-Orbitrap) and was used for the first time to systematically analyze the absorbed components and metabolites in rat plasma after oral administration of the water extract of Sarcandra glabra. This extract is a well-known Chinese herbal medicine for the treatment of inflammation and immunity related diseases. The anti-inflammatory activities of the absorbed components were evaluated by measuring nitric oxide (NO) production and proinflammatory genes expression in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages. As a result, 54 components in Sarcandra glabra were detected in dosed rat plasma, and 36 of them were positively identified. Moreover, 23 metabolites were characterized and their originations were traced. Furthermore, 20 of the 24 studied components showed anti-inflammatory activities. These results provide evidence that this method efficiency detected constituents in plasma based on the anti-inflammatory mechanism of multiple components and would be a useful technique for screening multiple targets for natural medicine research.     

Drebrin在坐骨神经慢性压迫性损伤大鼠远位触液神经元的表达

为观察坐骨神经慢性压迫性损伤(chronic constriction injury,CCI)后大鼠远位触液神经元(distal cerebrospinal fluid con-tacting neurons,dCSF-CNs)中drebrin的表达,探讨免疫荧光技术用于dCSF-CNs研究的可能性,将雄性Sprague-Dawley大鼠随机分为空白对照组、假手术组和CCI组,采用侧脑室注射霍乱毒素亚单位B(choleratoxin subunit B,CB)与辣根过氧化物酶(horseradish peroxidase,HRP)结合物(CB-HRP)示踪标记大鼠dCSF-CNs,观测三组大鼠行为学评分,并应用免疫荧光双标记和激光共聚焦显微镜技术比较各组dCSF-CNs中drebrin的表达.结果显示,三组中仅CCI组大鼠痛阈下降,三组大鼠dCSF-CNs均显示清晰,空白对照组和假手术组dCSF-CNs胞浆内无drebrin表达,CCI组dCSF-CNs胞浆内drebrin表达较多.结果表明,应用免疫荧光双标记观察dCSF-CNs,形态清晰,技术可靠.dCSF-CNs可能参与了神经病理性疼痛的信息传递.     

生物碱的提取方法研究进展

生物碱是广泛存在于自然界天然植物中的碱性含氮有机化合物。大多数生物碱具有显著的生理活性,是许多药用植物的有效成分,提取与纯化是生物碱制备的关键环节。综述了生物碱制备的传统方法及新技术的应用进展,分析了它们的原理及优缺点,探讨了生物碱制备的发展前景。     

基于集对分析的城市生态系统健康评价—以兰州为例

城市生态系统是城市社会经济发展的基础和载体,但城市生态系统健康状况问题中包含多种不确定性因素,而集对分析可以有效处理这种不确定性.论文以特大型综合性城市兰州为研究案例,基于集对分析方法,构建包括生产力、生活态、生态势和生机度的城市生命力指数,诊断兰州城市生态系统2002至2008年间的健康状态.研究结果表明:2002～2008年,兰州市城市生态系统健康状况呈上升趋势,其健康联系度由2002年的0.451增至2008年的0.519,但总体水平仍不高.该研究为兰州市城市规划和生态建设推荐了重点行动领域,同时也可为兰州市实施可持续发展战略提供决策依据.