首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
本实验通过对大鼠间歇性低氧训练(IHT)结束后不同时段的心肌指数和组织酶等指标进行测试,评定一定周期的IHT后,机体所形成的有效的、积极的适应性变化可持续的时间段。从实验可得出:(1)IHT对大鼠有氧代谢能力促进作用能保持约3-6d;(2)心肌和骨骼肌中的琥珀酸脱氢酶(SDH)、细胞色素氧化酶(CCO)在IHT后,活性显著提高,表明IHT可通过促进氧的利用能力来提高机体有氧代谢能力;(3)经IHT后,心肌指数亦有显著性上升,表明IHT可从氧的运输方面促进机体有氧代谢能力。  相似文献   

2.
柠檬酸对 CHO 细胞生长和代谢的影响   总被引:1,自引:0,他引:1  
研究了重组中国仓鼠卵巢细胞(CHO)批培养过程中柠檬酸对细胞生长和代谢的影响。结果表明:柠檬酸明显抑制了细胞的生长。与对照组相比,添加12 mm o l/L柠檬酸的处理组细胞的葡萄糖比消耗速率(QG lc)降低了37.5%,渗透压提高了10.0%,乳酸生成量与葡萄糖消耗量的比值增加了27.0%,氨生成量与谷氨酰胺消耗量的比值也增加了。在谷氨酰胺代谢过程中,更多的谷氨酰胺经谷草转氨酶途径生成α-酮戊二酸,参与能量代谢。柠檬酸促使细胞更多地被捕获在G 1期,阻碍细胞的DNA合成,抑制细胞增殖,并促进蛋白的表达。  相似文献   

3.
利用光学显微镜对3科5属10种蕨类植物的叶表皮形态进行了观察和研究.结果表明:(1)它们的叶表皮细胞大多为不规则型,表皮细胞垂周壁均呈深波状;(2)气孔为下生型,多呈椭圆形;共观察到9种气孔器类型(不等细胞型、极细胞型、腋下细胞型、无规则四细胞型、放射状细胞型、聚合极细胞型、横列型、带状细胞型和围绕细胞型),每种植物具有2~6种不同类型的气孔器;(3)根据叶表皮特征,支持姬蕨科与碗蕨科合并,而凤尾蕨科与铁线蕨科单独成科.研究结果为姬蕨科、凤尾蕨科和铁线蕨科植物的系统演化及分类提供科学依据.  相似文献   

4.
为了探讨壳寡糖(COS)对He La细胞和A549细胞自噬性死亡的影响,利用不同浓度COS处理细胞后MTT法检测细胞的增殖抑制情况,采用MDC染色法观察自噬泡的形成,免疫荧光法检测LC3在细胞内的表达,Western-blot分析COS处理He La和A549细胞不同时间后细胞内LC3-Ⅱ/LC3-Ⅰ变化。结果表明,5.0 mg·m L-1COS对两种细胞的增殖抑制率最大,分别为52.15%和57.63%(P0.01)。与阴性对照相比,经COS处理后的细胞MDC染色细胞内荧光强度增加,且阳性信号聚集于核周区域;免疫荧光检测发现LC3阳性颗粒数明显增加,表明细胞内自噬体的数量增多。Western-blot检测分析随着COS处理细胞时间延长,LC3-Ⅱ/LC3-Ⅰ比值逐渐增大,显示细胞内自噬活性增强。由此推测COS能够通过诱导He La和A549细胞的自噬性死亡来抑制细胞增殖,为COS的抗肿瘤作用机制的研究提供理论依据。  相似文献   

5.
目的:探讨荔枝核提取物成分L2.3对人肝癌细胞HepG-2的生长抑制作用及其分子机制.方法:MTT法测定样品对HepG-2细胞的增殖抑制,荧光染色观察细胞凋亡;比色法检测样品对HepG-2中caspase-3、caspase-8和caspase-9活性的影响,流式细胞仪检测并分析Fas蛋白表达的变化.结果:L2.3对HepG-2细胞表现出时间及剂量依赖性增殖抑制活性(P<0.05),其半数抑制质量浓度为43.0 μg/mL;处理组细胞中出现致密浓染亮蓝色凋亡小体.较高质量浓度的L2.3处理细胞后,caspase-3、8、9的活性均呈时间依赖性增高(P<0.01),且Fas蛋白的表达也明显上调(P<0.05).结论:荔枝核提取物L2.3对HepG-2细胞有体外增殖抑制活性,并介导 caspase-3、caspase-8、caspase-9活性改变及Fas蛋白表达的上调,以此诱导细胞凋亡的发生.  相似文献   

6.
兔成骨细胞的体外培养及生物学行为观察   总被引:2,自引:0,他引:2  
以一月龄幼兔的颅顶骨为材料 ,采用组织块法 ,进行细胞的原代培养并传代之 .结果显示 :(1)原代细胞具有成骨细胞的形态特征 ,经 6次传代后细胞形态变化不明显 ;(2 )细胞具有较强的碱性磷酸酶 (AL P)活性且稳中有升 ;(3)细胞培养液和细胞内均含有骨钙素 ;(4)连续培养 1个月后 ,成骨细胞有矿化结节形成 ;(5 )骨片经 4次贴壁仍有细胞爬出且细胞形态相同 .该结果表明所培养的细胞具有成骨细胞的生物学行为 ,为骨细胞生物学和骨组织工程的研究提供了一种客观而有效的手段  相似文献   

7.
LR—98对肝癌细胞增殖的抑制性效应   总被引:1,自引:0,他引:1  
利用在体和离体实验相结合 ,以动物接种肿瘤细胞后的生存时间、瘤重与体重比值、肝癌细胞生存率、超氧化物歧化酶 (SOD)活性及肝癌细胞凋亡为指标 ,研究了不同剂量榄仁树叶提取物 (LR 98)对肝癌细胞增殖的抑制性效应及可能机制 .在体实验结果表明 ,5× 10 - 3g/mLLR 98处理组动物的生存时间较对照组明显延长 (P <0 .0 1) ,不同剂量处理组 (5× 10 - 3g/mL ,2× 10 - 2 g/mL ,5× 10 - 2 g/mL)的瘤重与体重比值均较对照组明显减小 (P <0 .0 5) .体外培养的细胞经不同剂量LR 98(1× 10 - 5g/mL ,5× 10 - 5g/mL ,1× 10 - 4 g/mL)作用后 ,生存率及SOD活性均显著下降 (P <0 .0 1) .流式细胞仪分析表明 ,不同剂量LR 98作用于肝癌细胞 8h后 ,在G1 期前均出现一亚二倍体峰 ,表明均能诱导肝癌细胞发生凋亡 ,凋亡率分别达 2 9.4 4 % ,2 4 .4 5%和 2 5.2 2 % .以上结果说明LR 98可显著抑制肝癌细胞增殖 .降低SOD活性 ,诱导肝癌细胞凋亡可能是LR 98抑制肝癌细胞生长的机理之一 .  相似文献   

8.
实验选用常见的三叶浮萍作为植物材料,选择Cr6+为实验重金属,柠檬酸作为螯合剂,研究了Cr6+及在柠檬酸存在时对浮萍的生长率、可溶性蛋白质含量及POD活性的影响,结果表明:(1)随着Cr6+浓度的升高,三叶浮萍的生长受到抑制,但并未达到半数抑制浓度.当柠檬酸存在时,其抑制作用更加显著,且96 h-IC50为6.04 mg/L.(2)经4 d处理,加柠檬酸和未加柠檬酸的Cr6+处理组的可溶性蛋白质含量比对照组高出185.54%和112.5%.(3)经4d处理,三叶浮萍的POD活性总体表现为低促高抑,且均在浓度为5mg/L时达到峰值,柠檬酸存在的Cr6+处理组的POD活性高于单独的Cr6+处理组.(4)柠檬酸的螯合作用可使Cr6+活化,从而对植物的生态毒性增强,与Cr6+表现为协同作用.  相似文献   

9.
目的探讨不同剂量的二十二碳六烯酸(DHA)对棕榈酸(PA)培养后的HepG2细胞甘油三酯和胆固醇合成的影响。方法 HepG2细胞分为无血清培养基培养的对照组和含有0.25 mmol/L PA的无血清培养基培养的PA组以及用DHA替代20%、50%、100%PA的DHA替代组。对照组和PA组培养24 h后用无酚红低糖培养基鉴定细胞是否出现胰岛素抵抗,并测定细胞内甘油三酯(TG)、胆固醇(TCH)水平;模型成立后用DHA替代20%、50%、100%PA培养12 h,再次检测细胞葡萄糖摄取量、TG和TCH水平,Western blot检测脂肪酸、胆固醇合成关键基因SREBP-1c和SREBP-2的蛋白表达水平。结果 PA处理后HepG2细胞活性明显下降,葡萄糖摄取量显著低于NC组(P0.05),说明HepG2细胞出现胰岛素抵抗,且PA组TG、TCH水平均有不同程度的升高;用DHA替代PA后,细胞活性有所改善,葡萄糖摄取量较PA组有明显升高(P0.05),TG、TCH水平较PA组均有不同程度的降低,并且SREBP-1c和SREBP-2表达随DHA浓度升高呈下降趋势(P0.05)。结论 DHA可抑制SREBP-1c和SREBP-2的表达,从而抑制TG、TCH的合成,改善细胞脂代谢紊乱及胰岛素抵抗。  相似文献   

10.
ABA和GA刺激的ROS代谢调节水稻幼根伸长分析   总被引:2,自引:0,他引:2  
本文探索水稻幼根生长过程中ABA和GA对ROS代谢的影响,结果显示:低于0.5μmol/L的ABA促进根伸长,超过此浓度的ABA抑制根伸长;H2O2与ABA相似,低浓度促进而高浓度抑制;在观察浓度范围内,GA促进根伸长.利用3,3'-二氨基联苯胺(diaminobenzidine,DAB)组织化学染色方法检测根尖部位H2O2代谢情况,结果显示,对照、ABA,GA和ABA+GA处理后,根尖分别呈现浅黄色、深棕色、黄色和深棕色,说明ABA比GA诱导较多H2O2产生.进一步研究发现,ABA和ABA+GA分别上调过氧化物酶(peroxidase,POD)活性13.4%和8.37%,GA下调POD活性19.0%;同时,ABA和ABA+GA处理分别下调过氧化氢酶(catalase,CAT)活性14.8%和16.3%,GA则上调CAT活性5.16%.以上结果表明,ABA可能通过上调POD和抑制CAT活性来提高ROS含量,而GA与之相反,严谨控制ROS浓度,促进水稻生长.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号