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1.
目的：研究低氧条件下的冲刺训练对运动员身体内葡萄糖、胰岛素、游离脂肪酸以及乳酸应激条件下的影响。方法：所有运动员都分别参加三组不同实验条件的训练,并且每组训练相隔7天。三组不同训练条件分别为：常氧压的冲刺运动（N组）;中等缺氧的冲刺运动（M组）;高度缺氧的冲刺运动(H组)。每组冲刺运动都在功率自行车上进行,每组运动为4次为时30s的冲刺运动,阻力都为10档,并辅以教练口头激励,每次冲刺运动后恢复6min,并记录每次运动员产生的最高功率以及平均功率。两种不同的低氧条件由低氧面具提供。训练后,分别在运动前抽取血液1次,以及在4次运动完成后5min,30min,60min,120min各取一次,并检测各项指标。结果：1.常氧压组与两组低氧压组相比,血细胞中的葡萄糖含量没有明显的差异,但是,与没有进入运动开始前相比较,冲刺运动后的5min内葡萄糖含量上升显著。2.只有在冲刺运动完成后2h后,体内脂肪酸含量才显著上升,并且与常氧压组和中等低氧压组相比较,高度缺氧组的游离脂肪酸上升更为明显,且与这两组差异显著。3.与运动开始前相比,运动后5min、30min、60min内体内乳酸含量高,且具有显著差异。但在120min后差异消失。4.运动结束后5min时体内胰岛素含量较高,且与开始运动前和运动结束后其他三个时间段相比,具有显著差异。 相似文献
2.
Metabolic dependence of fast axoplasmic transport in nerve 总被引：4，自引：0，他引：4
Fast axoplasmic transport, shown in cat sciatic nerves by a crest of labeled activity after injection of the L7 ganglion with [(3)H]-leucine or [ (3)H]-lysine, was stopped within 15 minutes after death of the animals by bleeding. If the sciatic nerves were removed from the animals and placed in a chamber supplied with oxygen at 38 degrees centigrade, fast transport was sustained. Transport was rapidly blocked in similar in vitro preparations when the nerves were kept in a nitrogen environment. Fast axoplasmic transport is closely dependent upon oxibdative metabolism. 相似文献
3.
Protein modification by amino acid addition is increased in crushed sciatic but not optic nerves 总被引：3，自引：0，他引：3
S Shyne-Athwal R V Riccio G Chakraborty N A Ingoglia 《Science (New York, N.Y.)》1986,231(4738):603-605
Rat optic and sciatic nerves were crushed, and 10 minutes to 3 days later nerve segments between the crushed site and the cell body were removed and assayed for posttranslational protein modification by amino acid addition. Protein modification was comparable in intact optic and sciatic nerves, but in sciatic nerves increased to 1.6 times control levels 10 minutes after crushing and reached a maximum of ten times control levels by 2 hours. In optic nerves activity was decreased throughout the time course studied. The results indicate that, in a nerve which is capable of regeneration (sciatic), protein modification by the addition of amino acids increases immediately after injury, but a nerve incapable of regeneration (optic) is incapable of activating the modification reaction. These findings may be important in understanding the reasons for the lack of a regenerative response after injury to central mammalian nerves. 相似文献
4.
San Carlos olivine crystals under laboratory conditions of 26 gigapascals and 973 to 1473 kelvin (conditions typical of subducted slabs at a depth of 720 kilometers) for periods of a few minutes to 19 hours transformed to the phase assemblage of perovskite and magnesiowustite in two stages: (i) the oxygen sublattice transformed into a cubic close-packed lattice, forming a metastable spinelloid, and (ii) at higher temperatures or longer run durations, this spinelloid broke down to perovskite and magnesiowustite by redistributing silicon and magnesium while maintaining the general oxygen framework. The breakdown was characterized by a blocking temperature of 1000 kelvin, below which olivine remained metastable, and by rapid kinetics once the reaction was activated. 相似文献
5.
A dimeric hemoglobin was purified from nitrogen-fixing root nodules formed by association of Rhizobium with a nonleguminous plant, Parasponia. The oxygen dissociation rate constant is probably sufficiently high to allow Parasponia hemoglobin to function in a fashion similar to that of leghemoglobin, by oxygen buffering and transport during symbiotic nitrogen fixation. The identification of hemoglobin in a nonlegume raises important questions about the evolution of plant hemoglobin genes. 相似文献
6.
利用碱性蛋白酶酶解技术对新鲜猪血进行血红素提取。采用响应面分析法对酶解时间、酶解温度、酶解pH、酶与底物浓度比等因素进行了优化。结果表明,酶解最佳条件为：酶解温度59．3℃、酶解pH8．6和酶解时间125．0min和酶底物浓度比4680．0U,在此条件下,血红素的得率为72％、提取粗品纯度为33．8％。 相似文献
7.
A heterodont bivalve mollusk Calyptogena magnifica, from the East Pacific Rise and the Galápagos Rift hydrothermal vent areas, contains abundant hemoglobin in circulating erythrocytes. No other known heterodont clam contains a circulating intracellular hemoglobin. The hemoglobin is tetrameric and has a relatively high oxygen affinity, which varies only slightly between 2 degrees and 10 degrees C. The presence of hemoglobin in the clam may facilitate the transport of oxygen to be used in chemoautotrophic hydrogen sulfide metabolism. 相似文献
8.
Aspirin: action on receptor in the tooth 总被引：1，自引：0，他引：1
D Scott 《Science (New York, N.Y.)》1968,161(837):180-181
Impulse frequency recorded from dentinal receptors in the cat's tooth provided an indication of sensory excitation. Topical application of aspirin to the dentin promptly inhibited both steady-state discharge and response to a brief heat stimulus. When the drug was washed out, the initial excitability was restored in 15 minutes. 相似文献
9.
Survival at extreme altitude: protective effect of increased hemoglobin-oxygen affinity 总被引：3，自引：0，他引：3
Decreased hemoglobin-oxygen affinity is thought to be of adaptive value to humans and nonindigenous animals at high altitude. To test this, hemoglobin-oxygen affinity was modified by carbamoylation of hemoglobin in rats. Exposure of control (low oxygen affinity) and experimental (high oxygen affinity) animals to a pressure equivalent to high altitude revealed that increased, rather than decreased, hemoglobin-oxygen affinity will permit survival at greatly reduced environmental oxygen pressures. 相似文献
10.
葡聚六糖对烟草悬浮培养细胞活性氧的作用 总被引：1，自引：1，他引：0
研究了葡聚六糖对烟草悬浮培养细胞活性氧的作用.结果表明:葡聚六糖可以诱导烟草悬浮细胞活性氧的进发,活性氧进发蜂值出现在30 min,同时活性氧相关酶系活性也升高,超氧化物歧化酶(SOD)活性最高峰在处理后60 min,过氧化物酶(POD)和过氧化氢酶(CAT)变化趋势与活性氧相似.添加不同抑制剂EGTA、新霉素、氯化锂(LiCl)等测定发现,细胞胞内和胞外Ca2+参与调控葡聚六糖诱导的活性氧进发. 相似文献
11.
B Sullivan 《Science (New York, N.Y.)》1967,157(794):1308-1310
Natrix taxispilota hemoglobin has a very high oxygen affinity which depends upon pH in an unusual manner. The oxygen affinity increases slightly upon protein dilution, but the pK's of the Bohr groups are unchanged. Oxidation promotes hemoglobin polymerization, which can be inhibited by prior treatment with iodoacetamide. Reaction with iodoacetamide also causes a slight increase in the oxygen affinity, no change in the pK's of the Bohr groups, and a drastic reduction in heme-heme interaction. 相似文献
12.
COLLINS RE 《Science (New York, N.Y.)》1961,133(3464):1593-1594
A mathematical theory is developed to explain the observed enhancement of oxygen transport through solutions by hemoglobin. At high partial pressures of oxygen, ordinary diffusion through the solvent accounts for all transport of oxygen, but at low partial pressures the transport may be increased many fold by the presence of hemoglobin. This phenomenon is explained and the possible role of this phenomenon in living organisms is discussed. The theory also indicates a new method of determining dissociation curves from diffusion experiments. 相似文献
13.
采用强制通风静态筒堆肥系统,测量不同通风量下的堆体内的耗氧速率和氧气浓度,对堆肥过程中不同通风量下耗氧速率的差异、氧气浓度的动态变化进行了分析.结果表明,堆肥过程中耗氧速率和含水率有很大的关系,含水率偏高,耗氧速率下降,本实验中耗氧速率先降后升再下降,后期下降不明显;在整个堆肥过程中,堆体内的氧气浓度总体呈上升趋势,中后期氧气浓度增加比前期明显;停止通风后5 min内氧气消耗速率最快,之后消耗速度缓慢;本系统的最佳通风量为0.35 m3/min. 相似文献
14.
Delay time of hemoglobin S polymerization prevents most cells from sickling in vivo 总被引：10，自引：0，他引：10
A laser photolysis technique has been developed to assess the quantitative significance of the delay time of hemoglobin S gelation to the pathophysiology of sickle cell disease. Changes in the saturation of hemoglobin S with carbon monoxide produced by varying the intensity of a photolytic laser beam were used to simulate changes in the saturation of oxyhemoglobin S produced by variations in oxygen pressure. The presence of polymer at steady-state saturation with carbon monoxide was determined by measurement of the kinetics of gelation after complete photodissociation. The kinetics are a very sensitive probe for polymer since small amounts of polymerized hemoglobin increase the rate of nucleation sufficiently to eliminate the delay period. First, the equilibrium gelation properties of partially photodissociated carbonmonoxyhemoglobin S were shown to be the same as partially oxygenated hemoglobin S, and the method was then used to determine the effect of saturation on the formation and disappearance of polymers in individual sickle cells. The saturation at which polymers first formed upon deoxygenation was much lower than the saturation at which polymers disappeared upon reoxygenation. The results indicate that at venous saturations with oxygen, gelation takes place in most cells at equilibrium, but is prevented from occurring in vivo because the delay times are sufficiently long that most cells return to the lungs and are reoxygenated before polymerization has begun. 相似文献
15.
Mammalian cells respond to changes in oxygen availability through a conserved pathway that is regulated by the hypoxia-inducible factor (HIF). The alpha subunit of HIF is targeted for degradation under normoxic conditions by a ubiquitin-ligase complex that recognizes a hydroxylated proline residue in HIF. We identified a conserved family of HIF prolyl hydoxylase (HPH) enzymes that appear to be responsible for this posttranslational modification. In cultured mammalian cells, inappropriate accumulation of HIF caused by forced expression of the HIF-1alpha subunit under normoxic conditions was attenuated by coexpression of HPH. Suppression of HPH in cultured Drosophila melanogaster cells by RNA interference resulted in elevated expression of a hypoxia-inducible gene (LDH, encoding lactate dehydrogenase) under normoxic conditions. These findings indicate that HPH is an essential component of the pathway through which cells sense oxygen. 相似文献
16.
透明颤菌血红蛋白基因在吸水链霉菌NND-52-C中的克隆与表达 总被引：1，自引：0，他引：1
将透明颤菌血红蛋白基因(vgb基因)克隆至链霉菌的质粒载体pIJ702中，构建成表达载体pLY702，并将pLY702质粒转化阿扎霉素B的高产菌株——吸水链霉菌NND—52—C的原生质体，获得转化子H。经发酵实验表明，在限氧的条件下，可以使NND—52—C菌株的生物量提高14．4％，阿扎霉素B的产量提高30．8％。 相似文献
17.
Synthesis of functional human hemoglobin in transgenic mice 总被引：18，自引：0，他引：18
R R Behringer T M Ryan M P Reilly T Asakura R D Palmiter R L Brinster T M Townes 《Science (New York, N.Y.)》1989,245(4921):971-973
Human alpha- and beta-globin genes were separately fused downstream of two erythroid-specific deoxyribonuclease (DNase) I super-hypersensitive sites that are normally located 50 kilobases upstream of the human beta-globin gene. These two constructs were coinjected into fertilized mouse eggs, and expression was analyzed in transgenic animals that developed. Mice that had intact copies of the transgenes expressed high levels of correctly initiated human alpha- and beta-globin messenger RNA specifically in erythroid tissue. An authentic human hemoglobin was formed in adult erythrocytes that when purified had an oxygen equilibrium curve identical to the curve of native human hemoglobin A (Hb A). Thus, functional human hemoglobin can be synthesized in transgenic mice. This provides a foundation for production of mouse models of human hemoglobinopathies such as sickle cell disease. 相似文献
18.
以通O2氧化Mn(OH)2制备的水钠锰矿为前驱物,采用微波加热合成钙锰矿,并探讨微波的功率、反应温度、时间和pH值等条件对钙锰矿形成的影响。结果表明:一定微波条件下可快速合成粒径均一、结晶度较好的钙锰矿。当微波辐照功率大于150 W时,随着微波功率升高,合成钙锰矿所需时间缩短,600 W功率下20min即可快速得到钙锰矿;温度越高合成钙锰矿所需时间也越短,体系温度为100℃时不能生成钙锰矿,但升高到140℃时,20min即可合成出钙锰矿;在酸性条件下合成钙锰矿的转化率低,而中性和碱性条件下钙锰矿的形成速度快、转化率高、结晶度好。 相似文献
19.
Hyperbaric nitrogen at a pressure of 100 atmospheres increases significantly the affinity of erythrocytic hemoglobin for oxygen. This results in oxygen dissociation curves which are shifted to lower than normal oxygen partial pressures. The pressure effect is completely reversible and can therefore be observed only during exposure of the blood cells to the hyperbaric gas. 相似文献
20.
对獭兔RAPD体系中Taq DNA聚合酶浓度、引物浓度、基因组DNA浓度进行研究。结果表明:Taq酶浓度为1.0 U,引物浓度为10 pmol/μl,基因组DNA浓度为50 ng/μl时,可获得清晰、稳定性好的条带。优化的RAPD反应体系为:总体积为20.0μl。10×Buffer(含Mg2+)为2.0μl;dNTPs(各2.5 mmol/L)为2.0μl;Taq酶浓度为1.0 U,引物浓度为10 pmol/μl,基因组DNA浓度为50 ng/μl;超纯水为13.8μl。PCR扩增条件为:97℃预变性7 m in,94℃1 m in,36℃退火1 m in,72℃2 m in,45个循环后,在72℃延伸10 m in结束,4℃保存。PCR扩增产物通过1.4%的琼脂糖凝胶电泳检测。点样后,以2~3 V/cm电压降稳压电泳3.0~3.5 h。 相似文献