太极拳运动对老年人步态稳定性的影响

目的:本实验通过对比老年人参加太极拳锻炼后的步态学参数的变化,旨在探究太极拳运动对老年人步态稳定性的影响。方法:(1)研究对象:选取40名社区老年人为研究对象。其中练习太极拳两年以上者20人为实验组(练习内容均为简化二十四式太极拳),其中男女各10名;未曾练习太极拳而且未参加其他项目锻炼者20名为对照组,其中男女各10名。(2)测试方法:采用BIODEX步态训练仪对两组不同老年人进行步态测试。实验数据采用SPSS13.0统计软件进行处理,以P<0.05为有显著性差异,P<0.01为有非常显著性差异。结果:随着年龄的增长,老年人的步态稳定性逐渐下降,同年龄段的老年人女性的步态稳定性优于男性老年人,男性老年人步长大于女性老年人。女性老年人的左脚功能明显优于男性老年人左脚功能。长期参加太极拳锻炼的老年人步态稳定性明显提高,在步速一定的情况下,通过加大步长,降低步频提高了步态的稳定性。结论:太极拳锻炼对促进老年人步态稳定提高平衡能力有显著效果,经常参加太极拳锻炼有助于老年人下肢功能的维持,应大力开展老年人太极拳锻炼。     

Neuropeptide Y induces cardiomyocyte hypertrophy via calcineurin signaling in rats

Neuropeptide Y (NPY) has been shown to participate in cardiac hypertrophy. However, the mechanisms by which NPY induces cardiomyocyte hypertrophy are poorly understood. This study tested the hypothesis that NPY induces cardiomyocyte hypertrophy through Ca2+/CaM-dependent calcineurin (CaN) pathway in cultured neonatal rat cardiomyocytes. After 24-h treatment, NPY (100 nM) significantly increased 3H-leucine incorporation and c-Jun mRNA expression, concomitant with augment of CaN activity and protein level in cardiomyocytes compared to those cells without NPY treatment. The enhancement of 3H-leucine incorporation and c-Jun mRNA expression in cardiomyocytes treated with NPY were markedly inhibited by cyclosporine A (CsA), a selective inhibitor of CaN. We also investigated the effect of NPY on intracellular Ca2+ level in cardiomyocytes. There were no obvious changes in intracellular Ca2+ level of cytoplasm and nucleus in cardiomyocytes treated with NPY (100 nM) for 10 min. However, NPY significantly increased intracellular Ca2+ level of cytoplasm and nucleus in cardiomyocytes after 24-h treatment. The result suggested that NPY could induce hypertrophy of cardiomyocytes via Ca2+/CaM-dependent CaN signal pathway. The enhancement of [Ca2+]i caused by NPY may activate CaN signal pathways to mediate cardiac hypertrophy.     

Insulin resistance due to phosphorylation of insulin receptor substrate-1 at serine 302

Inhibitory serine phosphorylation is a potential molecular mechanism for insulin resistance. We have developed a new variant of the yeast two-hybrid method, referred to as disruptive yeast tri-hybrid (Y3H), to identify inhibitory kinases and sites of phosphorylation in insulin receptors (IR) and IR substrates, IRS-1. Using IR and IRS-1 as bait and prey, respectively, and c-Jun NH(2)-terminal kinase (JNK1) as the disruptor, we now show that phosphorylation of IRS-1 Ser-307, a previously identified site, is necessary but not sufficient for JNK1-mediated disruption of IR/IRS-1 binding. We further identify a new phosphorylation site, Ser-302, and show that this too is necessary for JNK1-mediated disruption. Seven additional kinases potentially linked to insulin resistance similarly block IR/IRS-1 binding in the disruptive Y3H, but through distinct Ser-302- and Ser-307-independent mechanisms. Phosphospecific antibodies that recognize sequences surrounding Ser(P)-302 or Ser(P)-307 were used to determine whether the sites were phosphorylated under relevant conditions. Phosphorylation was promoted at both sites in Fao hepatoma cells by reagents known to promote Ser/Thr phosphorylation, including the phorbol ester phorbol 12-myristate 13-acetate, anisomycin, calyculin A, and insulin. The antibodies further showed that Ser(P)-302 and Ser(P)-307 are increased in animal models of obesity and insulin resistance, including genetically obese ob/ob mice, diet-induced obesity, and upon induction of hyperinsulinemia. These findings demonstrate that phosphorylation at both Ser-302 and Ser-307 is necessary for JNK1-mediated inhibition of the IR/IRS-1 interaction and that Ser-302 and Ser-307 are phosphorylated in parallel in cultured cells and in vivo under conditions that lead to insulin resistance.     

高转移倾向乳腺癌细胞中p-ERK促进增殖和迁移作用的信号转导途径

在建立乳腺癌细胞MCF-7高转移倾向亚克隆LM-MCF-7细胞株的基础上,为阐明LM-MCF-7细胞具有更强增殖和迁移能力的分子机制,对其相关分子及其信号转导途径进行了探讨.免疫印迹结果显示,与MCF-7细胞相比,LM-MCF-7细胞中p-ERK1/2水平显著升高.流式细胞术和“伤口愈合”实验结果表明,ERK1/2的特异性抑制剂PD98059可明显抑制LM-MCF-7细胞的高增殖和高迁移能力.免疫印迹检测发现,与MCF-7细胞相比,LM-MCF-7细胞中与增殖和迁移相关的因子,如β-catenin、细胞周期蛋白D1、磷酸化肌球蛋白轻链（p-MLC）和肌球蛋白轻链激酶（MLCK）的水平呈明显增高,PD98059对这些因子水平的增高具有抑制作用.免疫荧光染色显示,LM-MCF-7细胞中β-catenin分布在细胞核中,应用PD98059处理后,β-catenin主要分布在胞浆中.上述研究结果表明,在LM-MCF-7细胞中活化的ERK1/2水平升高,是导致该细胞增殖和迁移能力增强的重要原因之一,与ERK1/2-MLCK-p-MLC和ERK1/2-β-catenin 细胞周期蛋白D1等信号转导途径有密切的关系.     

Plant community complexity in the arid valley of Minjiang River, southwestern China

Biocomplexity theory is becoming increasingly important in understanding natural vegetation dynamics and interrelation among all components of the ecosystem. In this study, based on the field investigation of plant species and environmental factors (altitude, microtopography, soil water content, and soil nutrients) in an arid valley of the upper reaches of Minjiang River, Sichuan Province, southwestern China, plant community complexity and its relationship with environmental factors, community diversity, species evenness and richness were studied. Both total and structural complexities of the communities showed a “high- low-high” tendency with the increase in altitude of the area, which meant that the complexity of communities was the highest at the sites of low and high altitude, whereas it was the lowest at the sites of intermediate altitude. It was found that the total community complexity had significant quadratic correlations with soil organic matter (SOM) content, total nitrogen (N), hydrolyzable N, soil water content, and available potassium (K), whereas it had no significant correlations with soil total K, total phosphorus (P), available P, and pH value. The total community complexity positively correlated with community diversity, species evenness and species richness, whereas the structural complexity negatively correlated with the community evenness. Of the two components of the total community complexity, namely, the structural complexity and the structural diversity, the structural complexity was more sensitive than the structural diversity to the changes of species in the community, which was not only related to the community evenness but also to the community richness. The relative contribution of both the structural complexity and the structural diversity to the total complexity would be different for different study areas or ecosystems.     

Survival and escape of Agrobacterium tumefaciens in triploid hybrid lines of Chinese white poplar transformed with two insect-resistant genes

Two partly modified insect-resistant genes (BtCryI Ac gene [Bt gene toxin against Lepidopterean insects] and API gene [arrowhead proteinase inhibitor]) were transferred to the triploid hybrid of Chinese white poplar ((Populus tomentosa Carr. × Populus bolleana Louche) × Populus tomentosa Carr.) mediated by A. tumefaciens. The survival of Agrobacterium in transgenic plants was examined during the processes of transplanting and subculturing on the nutrient medium. The results suggested that 80% of the plants, which were obtained by repeated selection on media added with 50 mg/L kanamycin and 300 mg/l carbenicillin, showed positive reactions after examination using molecular methods. The ELISA test indicated that the Bt toxoprotein was expressed in seven of the transgenic sub-clones. Leaves, stems, and roots of all the 28 transgenic plants were cultured on the YEB medium added with 50 mg/L kanamycin, and it was found that Agrobacterium survived in three sub-clones (33, 37, 5) and could have existed for 24 months in the bottle. These three transgenic sub-clones were transplanted and cultivated for one month in the room, and then the target Agrobacterium was found in rhizosphere of the sub-clone 33.     

草坪型扁穗牛鞭草种质资源的坪用价值初步评价

采用景观-性能-应用适合度的综合评价体系,以暖季型狗牙根和冷季型高羊茅为对照,分春季、夏季、秋冬季对西南地区扁穗牛鞭草坪用性状和使用性能进行评价,结果表明：春季草坪景观质量H050、H049的坪用性状好于对照;夏季H036、H049、H011坪用性状好于对照;秋冬季H036、H049表现好于对照;综合一年的表现进行指标权重分析,H036、H049得分分别为17．60和18．08,可作为过渡性气候区建植观赏草坪、游憩草坪、运动草坪、保土草坪的优质材料进行开发利用。     

EGCG对大鼠放射性肺损伤的防治作用及机制探索

目的:研究表没食子儿茶素-3-没食子酸酯(EGCG)对大鼠放射性肺损伤的防治作用及相关机制。方法:用60Co源γ射线单次照射SD大鼠全肺,构建放射性肺损伤模型,激素治疗组和EGCG治疗组大鼠分别给予地塞米松注射液和EGCG治疗;以肺系数、HE染色、Masson染色和肺组织羟脯氨酸(HYP)含量观察及评价EGCG对放射性肺炎及纤维化的改善情况;检测血清总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)含量;用Western印迹检测肺组织Nrf-2、HO-1、NQO-1的表达。结果:EGCG可明显减轻肺脏充血水肿,减低肺系数、肺组织HYP含量、肺泡炎及肺纤维化评分;EGCG可明显降低血清MDA水平,提高血清T-SOD活力,上调大鼠肺组织细胞Nrf-2、HO-1、NQO-1的表达水平。结论:EGCG能明显改善放射性肺损伤及纤维化病变,可能是通过Nrf2-ARE信号途径增加抗氧化酶表达,提高机体抗氧化能力而发挥治疗作用的。     

苯甲酰脲类杀虫剂对亚洲玉米螟生长发育和繁殖的效用

为全面评价苯甲酰脲类(BPUs)杀虫剂对亚洲玉米螟Ostrinia furnacalis(Guenée)的持续控制作用,采用叶片浸渍法,测定氟啶脲、除虫脲、氟铃脲和虱螨脲对亚洲玉米螟生长发育和繁殖的影响。结果表明,经4种BPUs处理后,亚洲玉米螟存活幼虫的历期延长了2.4～4.3d,平均单头雌、雄蛹重分别减轻了10.3～13.2mg和0～7.7mg,幼虫化蛹率和成虫交配成功率分别下降了14.1%～43.3%和5.6%～25.6%,产卵量降低了25.5%～53.3%,但卵孵化率没有明显改变。亚洲玉米螟雌、雄蛾吸食蔗糖水药液后,成虫寿命增加了1.3～4.3d,产卵量下降40.3%～58.2%,卵孵化率降低了32.9%～64.3%,F1代幼虫死亡率是对照组的3.5～8.5倍,表明苯甲酰脲类杀虫剂显著抑制了亚洲玉米螟幼虫生长发育和成虫的繁殖力。