共查询到20条相似文献，搜索用时 31 毫秒
1.
Diffuse retinal irradiation by visible light produces in the rat the death of visual cells and pigment epithelium. Typically, cage illumination of 1500 lux from fluorescent light through a green filter leads to severe damage when continued for 40 hours. Vitamin A deficiency protects against this damage but experiments show that retinol released by light from rhodopsin is probably not the toxic agent. Protection against light damage depends on a long-range state of cell adaptation to light itself. The normal diurnal cycle of light and dark seems to be the essential factor in controlling visual cell viability and susceptibility. 相似文献
2.
半胱胺、大豆黄酮对肉仔鸡脂肪代谢的影响 总被引：17，自引：0，他引：17
21日龄艾维茵商品代肉仔鸡 72只 ,随机分成对照组、日粮添加半胱胺 (CS)组和添加大豆黄酮 (Da)组。研究这两种物质对肉仔鸡脂肪代谢的影响。结果表明 ,在 35～ 4 9日龄两种物质均使血清中的胰岛素 (INS)和脂蛋白酯酶 (L PL)、肝中的苹果酸脱氢酶 (MD)水平低于对照组 (P <0 .0 1) ,CS组肉仔鸡增重提高 10 .30 % ,Da组增重提高 7.10 % (P <0 .0 5 ) ,CS组和 Da组增重至 4 9周龄达到高峰。CS组、Da组皮下脂肪厚度及腹脂率比对照组减少(P <0 .0 5 ) ,Da组减少尤为明显。试验结果提示半胱胺和大豆黄酮均有降低肉鸡脂肪沉积的作用 相似文献
3.
Yu SW Wang H Poitras MF Coombs C Bowers WJ Federoff HJ Poirier GG Dawson TM Dawson VL 《Science (New York, N.Y.)》2002,297(5579):259-263
Poly(ADP-ribose) polymerase-1 (PARP-1) protects the genome by functioning in the DNA damage surveillance network. PARP-1 is also a mediator of cell death after ischemia-reperfusion injury, glutamate excitotoxicity, and various inflammatory processes. We show that PARP-1 activation is required for translocation of apoptosis-inducing factor (AIF) from the mitochondria to the nucleus and that AIF is necessary for PARP-1-dependent cell death. N-methyl-N'-nitro-N-nitrosoguanidine, H2O2, and N-methyl-d-aspartate induce AIF translocation and cell death, which is prevented by PARP inhibitors or genetic knockout of PARP-1, but is caspase independent. Microinjection of an antibody to AIF protects against PARP-1-dependent cytotoxicity. These data support a model in which PARP-1 activation signals AIF release from mitochondria, resulting in a caspase-independent pathway of programmed cell death. 相似文献
4.
甘草酸二钾体外诱导感染MDV鸡胚成纤维细胞 凋亡发挥抗病毒作用 总被引：1，自引：0，他引：1
【目的】探讨甘草酸二钾体外抗MDV的活性及作用机制。【方法】在体外以鸡胚成纤维细胞为MDV增殖模型,利用MTT比色法、噬斑减少法通过抗病毒试验、病毒复制抑制试验、直接灭活试验来评价甘草酸二钾的抗病毒效果;并通过细胞凋亡试验解释其抗病毒机制。【结果】抗病毒试验结果表明,在安全浓度范围内,甘草酸二钾在体外具有较强的抗MDV的活性,其EC50为（893.5±36.99）µg•mL-1,SI>3.36,最大抑制率达94.4%;在病毒复制抑制试验中,甘草酸二钾可以抑制病毒复制的整个过程;病毒直接灭活试验表明甘草酸二钾可直接杀灭病毒粒子且不呈时间依赖性;细胞凋亡试验结果显示甘草酸二钾能够诱导感染MDV的鸡胚成纤维细胞凋亡。【结论】甘草酸二钾在体外具有抗MDV的活性,可以通过诱导感染病毒的鸡胚成纤维细胞凋亡发挥抗病毒作用。 相似文献
5.
Function and autoregulation of yeast copperthionein 总被引：32，自引：0，他引：32
6.
The RAD9 gene controls the cell cycle response to DNA damage in Saccharomyces cerevisiae 总被引：128，自引：0，他引：128
Cell division is arrested in many organisms in response to DNA damage. Examinations of the genetic basis for this response in the yeast Saccharomyces cerevisiae indicate that the RAD9 gene product is essential for arrest of cell division induced by DNA damage. Wild-type haploid cells irradiated with x-rays either arrest or delay cell division in the G2 phase of the cell cycle. Irradiated G1 and M phase haploid cells arrest irreversibly in G2 and die, whereas irradiated G2 phase haploid cells delay in G2 for a time proportional to the extent of damage before resuming cell division. In contrast, irradiated rad9 cells in any phase of the cycle do not delay cell division in G2, but continue to divide for several generations and die. However, efficient DNA repair can occur in irradiated rad9 cells if irradiated cells are blocked for several hours in G2 by treatment with a microtubule poison. The RAD9-dependent response detects potentially lethal DNA damage and causes arrest of cells in G2 until such damage is repaired. 相似文献
7.
Extracellular acidosis protects Ehrlich ascites tumor cells and rat renal cortex against anoxic injury 总被引：5，自引：0，他引：5
The present study indicates that extracellular acidosis protects Ehrlich ascites tumor cells and rat kidney cortex cells against injury from anoxia. Parameters measured included cell potassium, adenosine 5'-triphosphate, and uptake of vital dyes. Cells survived longer at a pH of 5.6 to 6.5 than at a pH of 7.4; pH 7.9 was most detrimental. These findings indicate that production of protons by anoxic cells may be a protective feedback mechanism. 相似文献
8.
Schneider H Downey J Smith A Zinselmeyer BH Rush C Brewer JM Wei B Hogg N Garside P Rudd CE 《Science (New York, N.Y.)》2006,313(5795):1972-1975
The coreceptor cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is pivotal in regulating the threshold of signals during T cell activation, although the underlying mechanism is still not fully understood. Using in vitro migration assays and in vivo two-photon laser scanning microscopy, we showed that CTLA-4 increases T cell motility and overrides the T cell receptor (TCR)-induced stop signal required for stable conjugate formation between T cells and antigen-presenting cells. This event led to reduced contact periods between T cells and antigen-presenting cells that in turn decreased cytokine production and proliferation. These results suggest a fundamentally different model of reverse stop signaling, by which CTLA-4 modulates the threshold for T cell activation and protects against autoimmunity. 相似文献
9.
研究旨在观察在日粮中添加不同剂量半胱胺对淮南麻鸭生长性能及血液中生长抑素水平的影响.选用1日龄淮南麻鸭200羽,随机分成4组,每组5个重复,每个重复10羽.从8日龄开始,分别在基础日粮中添加半胱胺0（对照组）、100、200、400 mg· kg-1（试验组）,连续饲喂28 d.结果表明,与对照组相比,添加半胱胺组的麻鸭试验末体重和日增重均显著提高（P＜0.05）,其中添加半胱胺200 mg· kg-1组麻鸭生长指标最佳;添加半胱胺组的麻鸭血液中生长抑素水平均显著降低（P＜0.05）,其中添加200 mg· kg-1剂量组麻鸭血液中生长抑素水平值最低.试验结果表明,日粮中适当添加半胱胺制剂可以促进淮南麻鸭生长发育,且其机制与降低血液中生长抑素浓度有关. 相似文献
10.
Hydroxyurea: differential lethal effects on cultured mammalian cells during the cell cycle 总被引：19，自引：0，他引：19
W K Sinclair 《Science (New York, N.Y.)》1965,150(704):1729-1731
Hydroxyurea has a differential lethal effect on cultured Chinesehamster cells that are at different stages in their cell cycle. Cells synthesizing DNA at the time of exposure to the drug are lethally damaged. Cells in the phase of growth preceding DNA synthesis (G(1)) survive but are prevented from beginning DNA synthesis. Cells in the phase after DNA synthesis (G(2)) survive and appear to progress until just before the beginning of the next period of DNA synthesis. This differential lethal and inhibitory effect of hydroxyurea may be useful for synchronizing asynchronous cell populations and explaining effects of the drug in human therapy. 相似文献
11.
大豆黄酮及半胱胺对产蛋后期鸡产蛋性能的比较 总被引：5，自引：0，他引：5
试验选用36只8月龄海兰褐产蛋后期鸡,随机分为3组,即对照组、半胱胺组、大豆黄酮组。对照组饲喂基础日粮,半胱胺(Cysteamine,Cs)组在基础日粮中添加Cs80mg·kg-1(体重),大豆黄酮(Daidzein,Da)组在基础日粮每千克饲料中添加Da3mg。结果表明,Cs组及Da组均能显著提高产蛋后期鸡产蛋率,且二者产蛋率总体水平分别比对照组增加21.39%(P<0.05)和14.19%(P<0.05);去掉直径>1.344cm卵黄的卵巢称重,Da组卵巢最重,比对照组增加37.3%(P<0.05),半胱胺组卵巢重比对照组增加2.5%;大豆黄酮组平均蛋重有升高趋势;Da组及Cs组孕酮水平均是对照组的1.063倍;Da组雌二醇总体水平分别是对照组及Cs组的1.2倍和1.24倍。 相似文献
12.
半胱胺对吲哚美辛诱发的大鼠胃粘膜溃疡的保护与抗氧化研究 总被引：1，自引：0，他引：1
为探讨半胱胺对动物应激性胃粘膜溃疡的保护和抗氧化机制,本研究利用吲哚美辛(IN)诱导大鼠胃部急性溃疡模型。选取雄性SD大鼠45只,体重180~220 g,随机分为3组,每组15只。对照组(A):灌服生理盐水1 mL/只;应激组(B):灌服吲哚美辛(45 mg/kg体重);抗氧化组(C):灌服半胱胺处理(100 mg/kg体重),1 h后灌服吲哚美辛(45 mg/kg体重)。结果表明:半胱胺明显抑制了吲哚美辛诱导的胃粘膜溃疡。与对照组A比较,灌服IN显著降低了胃粘膜中超氧化物歧化酶(SOD)活性以及谷胱甘肽(GSH)、线粒体中ATP、ADP、AMP、总腺苷酸和能荷(EC)水平(P<0.05),然而过氧化氢酶(CAT)明显提高,脂质过氧化物(LPO)产量显著增加。灌服半胱胺明显遏制了上述各项指标改变,显著提高了胃粘膜组织中SOD活性以及GSH、线粒体中总腺苷酸含量和EC值,同时降低了LPO和溃疡指数(P<0.05)。 相似文献
13.
Carlton JG Caballe A Agromayor M Kloc M Martin-Serrano J 《Science (New York, N.Y.)》2012,336(6078):220-225
The endosomal sorting complex required for transport (ESCRT) machinery plays an evolutionarily conserved role in cytokinetic abscission, the final step of cell division where daughter cells are physically separated. Here, we show that charged multivesicular body (MVB) protein 4C (CHMP4C), a human ESCRT-III subunit, is involved in abscission timing. This function correlated with its differential spatiotemporal distribution during late stages of cytokinesis. Accordingly, CHMP4C functioned in the Aurora B-dependent abscission checkpoint to prevent both premature resolution of intercellular chromosome bridges and accumulation of DNA damage. CHMP4C engaged the chromosomal passenger complex (CPC) via interaction with Borealin, which suggested a model whereby CHMP4C inhibits abscission upon phosphorylation by Aurora B. Thus, the ESCRT machinery may protect against genetic damage by coordinating midbody resolution with the abscission checkpoint. 相似文献
14.
不同年龄黄山松蒸腾速率及水分利用效率的比较研究 总被引：1，自引：0，他引：1
采用Li-6400便携式光合分析仪,研究不同年龄阶段的黄山松在不同季节的蒸腾及水分生理生态的变化.结果表明,3个年龄段黄山松1年生针叶的时蒸腾强度具有明显的日变化,均呈明显的双峰曲线,但是峰值出现时间不同;幼龄阶段的时蒸腾速率与时气孔导度的日变化趋势的基本相似,而中龄和中幼龄黄山松,其时均蒸腾速率与气孔导度的变化趋势具有明显的差异,说明幼龄黄山松受气孔的限制较明显;蒸腾速率日均值的季节变化3个年龄段黄山松均为夏季的蒸腾速率较高;各年龄段黄山松的水分利用效率变化曲线均为双峰型,年平均水分利用效率的排序为中幼龄(5.062)＞幼龄(3.383)＞中龄(3.011),中幼龄黄山松具有较高水分利用效率表明其能更好地适应干旱环境;通过季节均值比较,发现夏季黄山松具有较高的水分利用效率,是其能生长在土壤浅薄甚至岩缝中的一个主要原因之一. 相似文献
15.
Alpha-naphthoflavone: an inhibitor of hydrocarbon cytotoxicity and microsomal hydroxylase 总被引：5，自引：0，他引：5
Alpha-naphthoflavone inhibits the metabolism of 3,4-benzopyrene and 7,12-dimethylbenz(a)anthracene in hamster enlbryo cell cultures and protects the cells against the inhibition of cell multiplication by these carcinogens. Alphla-nalphthoflavone also inhibits the aryl hydrocarbon hydroxylase activity in homogenates of induced hamster embryo cells and in liver microsomes from rats previously treated with polycyclic aromatic hydrocarbons, but not in microsomes from control rats. 相似文献
16.
【目的】观察发情周期不同阶段牦牛子宫中ERα、PR mRNA和蛋白的表达变化。【方法】采用实时荧光定量PCR技术和免疫组织化学SP法分别对发情期、发情后期、间情期和发情前期牦牛子宫中ERα和PR mRNA及ERα和PR蛋白的表达特点进行了研究。【结果】发情周期不同阶段牦牛子宫内膜和肌层中均有ERα mRNA和 PR mRNA的表达,ERα和PR蛋白免疫阳性产物表达于子宫腔上皮细胞、腺上皮细胞、基质细胞、血管内皮细胞和子宫肌层平滑肌细胞中;子宫内膜中ERα mRNA和PR mRNA在发情后期表达最强,间情期显著下降（P＜0.05）,发情前期回升;ERα和PR蛋白表达在发情期最强而间情期最弱;子宫肌层中ERα mRNA和PR mRNA的表达在发情期较高,发情后期显著下降（P＜0.05）,间情期降到最低,发情前期显著回升（P＜0.05）,且达到最高值;ERα和PR蛋白发情期表达最强,间情期最弱,但其间无显著差异（P＞0.05）。【结论】ERα和PR在牦牛子宫内膜和肌层中随发情周期不同呈周期性变化,参与调节发情周期不同阶段牦牛子宫内膜及肌层功能的发挥。 相似文献
17.
大豆黄酮及半胱胺对鹅外周血液中胰岛素和胰高血素的影响 总被引：7，自引：3，他引：7
试验选用 2 1日龄雄性东北大白鹅 2 7只 ,随机分成 3组 :对照组 ,大豆黄酮 (Da)组和半胱胺 (Cs)组。在第 9周龄时 ,每组随机取 3只 ,装置临时性翅静脉血管插管 ,并于第 6 4,6 6 ,6 8日龄间隔一定时间 ,每天采集血样 4次 ,采用放射免疫法测定血液中胰岛素和胰高血糖素含量。结果表明 ,大豆黄酮组及半胱胺组外周血液中胰岛素含量较对照组分别升高 5 .0 % (P <0 .0 1)和6 .3% (P <0 .0 1) ;胰高血糖素分别升高 13.3% P <0 .0 1)和 18.8% (P <0 .0 1)。提示大豆黄酮及半胱胺可改变机体内某些激素的浓度来影响体内的物质代谢 相似文献
18.
The mechanisms by which quiescent cells, including adult stem cells, preserve their ability to resume proliferation after weeks or even years of cell cycle arrest are not known. We report that reversibility is not a passive property of nondividing cells, because enforced cell cycle arrest for a period as brief as 4 days initiates spontaneous, premature, and irreversible senescence. Increased expression of the gene encoding the basic helix-loop-helix protein HES1 was required for quiescence to be reversible, because HES1 prevented both premature senescence and inappropriate differentiation in quiescent fibroblasts. In some human tumors, the HES1 pathway was activated, which allowed these cells to evade differentiation and irreversible cell cycle arrest. We conclude that HES1 safeguards against irreversible cell cycle exit both during normal cellular quiescence and pathologically in the setting of tumorigenesis. 相似文献
19.
[目的]测定粟酒裂殖酵母高表达的SpTrz2p对其细胞周期的影响。[方法]将粟酒裂殖酵母的trz2+克隆到pREP4x质粒上,构建带有SpTrz2的高表达载体,将构建成功的重组子转化至野生型粟酒裂殖酵母细胞中,利用流式细胞仪检测细胞周期的变化。[结果]高表达SpTrz2p可导致酵母细胞形态和周期的改变,使大部分酵母细胞停留于G1期,这说明高表达SpTrz2p对细胞周期有明显影响。[结论]该研究结果表明高表达SpTrz2p给细胞造成的致死毒性是通过影响细胞周期实现的。 相似文献
20.
【目的】研究α-三联噻吩（α-T）对斜纹夜蛾（Spodoptera litura）SL细胞线粒体膜电位及细胞周期的影响。【方法】通过Rhodamine123染色和流式细胞术（flow cytometry,FCM）研究α-T处理SL细胞24 h和48 h后细胞线粒体膜电位的变化,并通过PI染色和FCM,测定α-T处理SL细胞24 h和48 h后细胞周期各时相百分率的变化。【结果】光活化后的α-T处理SL细胞24 h后,0.0625 μg•mL-1浓度和0.1250 μg•mL-1浓度处理组细胞线粒体膜电位的变化幅度不大,而0.5000 μg•mL-1浓度处理组细胞线粒体膜电位明显升高,48 h后高浓度处理组（1.0000 μg•mL-1）导致线粒体膜电位明显去极化;处理24 h后,低浓度（0.0625 μg•mL-1）处理组细胞被阻滞于S期,而高于此浓度的光照处理组细胞被阻滞于G2/M期,48 h后,浓度≤0.1250 μg•mL-1的光照处理细胞被阻滞于G2/M期,而浓度＞0.1250 μg•mL-1的光照处理组细胞被阻滞于S期。【结论】SL细胞经α-T处理后,细胞处于一系列复杂的动态变化中。当细胞本身不能扭转ROS造成的氧化损伤时,细胞线粒体膜电位和细胞周期时相即出现较大幅度的变化,这种变化决定着细胞的受损程度和细胞的死亡途径。 相似文献