慢性低氧及运动训练对大鼠血清一氧化氮(NO)含量及一氧化氮合酶(NOS)活力的影响

为观察慢性低氧及训练对大鼠的影响,取健康SD大鼠28只,随机分成4组:(1)常氧对照组(NC),(2)常氧训练组(NT),(3)低氧安静组(HC),(4)低氧训练组(HT)。其中HC、HE两个低氧组每天保证22h生活在模拟4000m高原的低氧舱(氧浓度12 7%),NT、HT两个训练组则每天进行跑台训练1h。28天后,各组均于安静状态下宰杀、取血,测定血清一氧化氮(NO)含量及一氧化氮合酶(NOS)活力。结果可见:28天后,与对照组相比,低氧安静组(HC)和低氧训练组(HT)大鼠血清NO浓度有较显著的降低(P<0 10),而常氧训练组(NT)下降不显著;另一方面,慢性28天后,与常氧对照组(NC)相比,常氧训练组(NT)及低氧对照组(HC)NOS活性虽有上升,但差异不显著;低氧训练组(HT)NOS活性则明显低于NT组及HC组(P<0 05)(P<0 10),这说明低氧及运动两种因素的效应并非是简单的叠加,可能相互抵消。其机制有待进一步研究。     

递增负荷运动对少年男篮运动员血浆NO代谢的影响

为探讨递增负荷运动过程中少年男篮血浆NO含量和NOS活性的变化规律,选取少年男篮运动员12名,普通健康少年学生12人作为对照组,同时进行递增负荷运动.测试结果表明:少年男篮组在安静时的NO的含量和NOS活性比普通少年组高(P＜0.05);运动后即刻各组NO的含量和NOS活性均升高,男篮组升高率大于普通组;恢复期各组NO的含量均降低,男篮组的恢复速度大于普通组.说明运动可以提高人体血清内NO的含量以及NOS活性;在运动过程中,有训练史者调节NO代谢的能力增强.     

刺五加提取物对大强度耐力运动大鼠不同组织 NO、NOS含量的影响

目的:探讨补充刺五加提取物对大强度耐力运动大鼠不同组织中NO、NOS含量的影响。方法:采用大强度耐力运动训练,通过补充刺五加提取物对比实验,观察大强度耐力运动后大鼠不同组织中NO、NOS含量的变化。结果:运动服药组心肌组织和肝脏组织中NO含量高于运动组,有显著性差异。运动服药组心肌组织中总NOS酶活性高于运动组,有显著性差异;运动服药组脑组织和肝脏组织中总NOS酶活性明显低于运动组,有显著性差异;运动组和运动服药组肾组织中总NOS酶活性无明显差异。结论:补充刺五加提取物可以使运动大鼠体内心肌组织和肝脏组织中一氧化氮(NO)的含量升高,改善运动大鼠心脏和肝脏中血管收缩状态,使血管舒张,血供增加。     

Study on the neurotoxic effects of low-level lead exposure in rats

Objective: To investigate effects of developmental lead exposure on nitric oxide synthase (NOS) activity in different brain regions and on N-methyl-D-aspartate (NMDA) receptor mRNA expression in the hippocampus of rats. On the basis of these observations, we explored possible mechanisms by which lead exposure leads to impaired learning and memorizing abilities in children. Methods: A series of rat animal models exposed to low levels of lead during the developing period was established (drinking water containing 0.025%, 0.05% and 0.075% lead acetate). NOS activities in the hippocampus, the cerebral cortex, the cerebellum and the brain stem were determined with fluorescence measurement and levels of mRNA expression of the NMDA receptor 2A (NR2A) subunit and NMDA receptor 2B (NR2B) subunit in the rat hippocampus were measured with Retro-translation (RT-PCR). Results: There were no differences in the body weight of rat pups between any of the groups at any given time (P>0.05). The blood lead level of Pb-exposed rat pups showed a systematic pattern of change: at 14 d of age, it was lower than that at 7 d of age, then rising to the peak level at 21 d and finally falling to lower levels at 28 d. The hippocampal NOS activities of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.01). NOS activities in the cerebellum of lead-exposed groups were all lower than that of the control group on the 21st and 28th day (P<0.001) and the NOS activity of the 0.025% group was significantly lower than that of the 0.05% and 0.075% groups on the 28th day (P<0.05). NOS activity in the cerebral cortex of the 0.075% group was significantly lower than that of the control, 0.025% and 0.05% groups on the four day spans (P<0.001). There was no significant difference of NOS activity in the brain stem between any lead-exposed group and the control group on the four day spans. In the 0.05% and the 0.075% groups, the level of NR2A mRNA expression was higher than that in the control group at 7 d and 14 d of age (P<0.05). In the 0.025% group, the level of NR2A was found to be higher than that in the control group at 7 d of age only (P<0.05). No significant differences were found for the levels of NR2B mRNA expression between any of the groups at any given time. Conclusions: NOS activity in the hippocampus, the cerebral cortex and the cerebellum are inhibited by lead exposure. The degree of the inhibitory effect depends on the time span of exposure and the lead concentration. Developmental low-level lead exposure was found to raise the level of NR2A mRNA expression in the hippocampus of rats. Developmental low-level lead exposure does not affect the level of NR2B mRNA expression in the hippocampus.     

The Heisenberg Microscope: A Powerful Instructional Tool for Promoting Meta-Cognitive and Meta-Scientific Thinking on Quantum Mechanics and the ‚Nature of Science’

In this paper, we present a multi-dimensional study concerning Heisenberg’s ‚gamma ray microscope’, a thought experiment, which is intimately connected with the historical development of quantum mechanics (QM), and also with the most disputed interpretations of quantum theory. In this study: (a) we investigate how philosophers of science read and explicate the function of thought experimentation in physical science; (b) in the light of relevant philosophical theories, we examine the complicated epistemological questions raised by the ‚gamma-ray microscope’ during the birth-process of QM and the contribution of this thought experiment to the clarification of the physical meaning of Heisenberg’s indeterminacy relations; (c) on the basis of the preceding analysis, we propose an instructional intervention, which aims at leading learners not only to an essential understanding of QM worldview, but to a deep insight into the Nature of Science as well.     

诱导型一氧化氮合酶在光暗调控的蚕豆气孔运动中的作用

以蚕豆叶片下表皮为材料,借助表皮条分析、免疫细胞化学染色、细胞核染色和激光扫描共聚焦显微镜技术,对一氧化氮(nitric oxide,NO)在光暗调控的蚕豆气孔运动中的作用进行探索。实验证明,NO专一性清除剂2,4-羧基苯-4,4,5,5-四甲基咪唑-1-氧-3-氧化物(cPTIO)和一氧化氮合酶(NOS)抑制剂NG-氮-L-精氨酸-甲酯(L-NAME)能够逆转黑暗诱导气孔关闭的效应,并能阻断黑暗诱导的蚕豆保卫细胞NO水平的提高。但二者对光下气孔孔径几乎没有影响。结果表明,光暗调控的蚕豆气孔运动与保卫细胞胞质内的NO水平有关,在保卫细胞细胞核中存在诱导型一氧化氮合酶(inducible-nitric oxide synthase,iNOS),而光暗条件下iNOS活性不同,进而引起NO水平变化并最终影响气孔开关。     

The relationship between biology teachers’ understanding of the nature of science and the understanding and acceptance of the theory of evolution

ABSTRACT

Despite the importance of the theory of evolution (TE) to scientific knowledge, a number of misconceptions continue to be found among biology teachers. In this context, the first objective of this study was to identify the impact of professional development programme (PDP) on teachers’ understanding of nature of science (NOS) and evolution and on the acceptance of this theory. Its second objective was to study the relationship among these variables. Three instruments were used to quantify these variables: the Views of the Nature of Science Version D (VNOS D+), the Assessing Contextual Reasoning about Natural Selection (ACORN), and the Measure of Acceptance of Theory of Evolution (MATE). The results indicate that the PDP had a positive impact on teachers, significantly improving their understanding of the NOS and natural selection, as well as their acceptance of the TE. Furthermore, a positive correlation between the understanding of the NOS obtained by teachers in the first part of the PDP and the understanding and acceptance of evolution that these teachers showed at the end of the programme was determined. However, no relationship between an understanding of the NOS and gains in the understanding and acceptance of evolution was found.     

科学本质理解的教学目标的设定

本文在分析当前科学本质理解的教学目标预设中存在的问题以及明晰其与三维目标的关系之后,以具体的案例说明科学本质理解应作为显性教学目标,在三维目标中凸显科学本质理解的丰富内涵。     

运动训练中NO与心血管系统的研究现状与问题

一氧化氮（NO）对人体具有广泛的生物学效应。国内外对NO与运动训练中心血管的关系已有相关研究,但也存在不少的问题,所以这仍是一个值得研究的问题。