Tissue metabolism under the influence of low oxygen tension
Tissue metabolism under the influence of low oxygen tension
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DOI：
10.1042/bj0311671
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发表时间：
1937-01-01
影响因子：
4.1
通讯作者：
Laser, H
中科院分区：
文献类型：
--
作者：
Laser, H
Warburg&KuBOWITZ[1929]表明，坎迪亚微球菌在氧分压低至10-5大气压(=0008 mm)时的呼吸作用。HG)与空气中的相同。他们的结果只有在实验条件下才能得到，这些实验条件确保了O2在这些小电池中的扩散梯度在非常低的氧压下应该是足够的。对于直径大约是微球菌直径的十倍的酵母细胞，当氧气压力超过该值时，呼吸开始下降，此时氧气在细胞内的扩散将成为限制因素。Meyerhof&Schulz[1932]发现在固氮菌中，呼吸的大小和氧分压之间有一定的关系。在含氧量为15-20%的大气中，摄氧量最高。在这个水平上，呼吸作用随着氧气浓度的增加而缓慢下降，随着氧气浓度的降低而迅速下降。通过对球形细菌的计算，排除了这些细胞内O2张力的梯度导致氧分压低于15%02时呼吸减弱的可能性。这些结果表明，在使用的最低氧气浓度(03%)下，细胞的直径比理论所要求的要小得多，从而在细胞内引起明显的02张力梯度。Bumm等人[1934]在研究豚鼠的肠粘膜时，比较了95%02和10%02的呼吸和糖酵解。他们发现，有氧糖酵解随着氧分压的降低而增加，呼吸的幅度保持不变。这意味着巴斯德效应取决于氧气的压力。粘膜厚度平均为1-0×10-2 cm。Leinert[1935]批评了这些结果，并指出组织切片不适合这样的实验，因为在低氧分压下，氧气的扩散可能成为限制因素。然而，这种批评失去了一些力量，原因如下：(1)Bumm等人已经证明了这一点。(2)Warburg[1927]用同样的氧气浓度(10%02)测试了其他几个组织：他的结果，特别是对整个胚胎的结果，其厚度超过肠粘膜的许多倍，推翻了这一观点。Leinert提出的第二个批评是，Bumm等人没有测量呼吸和糖酵解。Bumm等人认为，在相同的介质中(即在磷酸盐-林格介质中的摄氧量和在碳酸氢盐介质中的有氧糖酵解)是由于误解。实际上确实确定了林格重碳酸盐中的这两个数字[1934，第214页]。
WARBURG & KuBOWITZ [1929] showed that the respiration of Micrococcus candicans at oxygen tension as low as 10-5 atmosphere (= 0008 mm. Hg) does not differ from that in air. Their results were obtained only under experimental conditions which ensured that the diffusion gradient of 02 within these small cells should be adequate at the very low oxygen tensions. With yeast cells the diameter of which is about ten times larger than that of Micrococcus, the respiration began to decrease at an oxygen tension above that at which diffusion of 02 within the cell would become a limiting factor. Meyerhof & Schulz [1932] found that in Azotobacter croococcum there is a definite relationship between the magnitude of respiration and the oxygen tension. The highest level of oxygen uptake occurs in an atmosphere containing 15-20% oxygen. From this level the respiration decreases slowly with increasing and rapidly with decreasing oxygen concentration. The possibility that the gradient of 02 tension within these cells is responsible for the decrease of respiration at lower oxygen tensions than 15% 02 has been excluded by calculations for a spherical bacterium. These showed that at the lowest oxygen concentrations used (03%) the diameter of the cells was considerably smaller than that required by the theory to cause an appreciable gradient of 02 tension within the cell.Bumm et al.[1934], working with mucosa of the intestine ofthe guinea-pig, have compared respiration and glycolysis in 95% 02 and10% 02. They found that aerobic glycolysis increases with decreasing oxygen tension, the magnitude of respiration remaining unaltered. This means that the Pasteur effect depends upon the oxygen tension. The thickness of the mucosa was found on the average to be 1-0 x 10-2 cm. Leinert [1935] criticized these results and stated that tissue slices are unsuitable for such experiments because the diffusion of oxygen may become the limiting factor at low oxygen tension. This criticism loses, however, some ofits force for the following reasons:(1) it has been shown by Bumm et al. that the respiration rate was almost the same in 10% 02 as in 100% 02,(2) Warburg [1927] tested several other tissues with the same oxygen concentration (10% 02): his results, especially those on whole embryos, the thickness of which surpasses many times that of the intestinal mucosa, disproved this objection. The second criticism made by Leinert that respiration and glycolysis were not measured by Bumm et al. in the same media (namely oxygen uptake in phosphate-Ringer and aerobic glycolysis in bicarbonate-media) is due to a misunderstanding, for Bumm et al. actually did determine both figures in Ringer-bicarbonate [1934, p. 214].