LIFE AT HIGH TEMPERATURES - EVOLUTIONARY ECOLOGICAL AND BIOCHEMICAL SIGNIFICANCE OF ORGANISMS LIVING IN HOT SPRINGS IS DISCUSSED
LIFE AT HIGH TEMPERATURES - EVOLUTIONARY ECOLOGICAL AND BIOCHEMICAL SIGNIFICANCE OF ORGANISMS LIVING IN HOT SPRINGS IS DISCUSSED
复制标题
DOI：
10.1126/science.158.3804.1012
复制
发表时间：
1967-01-01
期刊：
影响因子：
56.9
通讯作者：
BROCK, TD
中科院分区：
文献类型：
--
作者：
BROCK, TD
生命存在的最高温度尚未确定。在黄石公园，一些细菌基本上在沸点生存和生长。由于增加的静水压力可以使细菌在更高的温度下生长，因此细菌似乎没有理由不能在自然界中任何有液态水的温度下生存。光合作用生物肯定有一个较高的温度，原核藻类的温度似乎在75摄氏度左右。Eu-caryotlc微生物被限制在较低的温度下（低于60[度]C），单细胞和多细胞动物的温度更低（低于50[度]C）。生活在特定温度下的蓝绿藻最能适应该温度，即使它接近藻类生长的上限。这些藻类不仅是扩大了生存范围的低温形式，而且实际上是进化的形式，因此它们的最佳温度与环境温度相似。热亲性的分子机制更可能与细胞膜的功能和稳定性有关，而不是与特定大分子的性质有关。在细菌中，每种生物都有许多酶，它们在生物的最佳温度下是稳定的，但在更高的温度下就不稳定了。生物体不会进化出比它们需要的稳定得多的蛋白质。这种生物在合成可变性蛋白质方面可能有一些优势。蛋白质的变性可能与目前有关酶的诱导拟合和变构相互作用的观点有关。虽然嗜热菌在其最佳状态下的生长速度比嗜热菌和嗜冷菌快一些，但其增长速度比阿伦卢斯方程所预测的要小得多。这表明，尽管热微生物对它们的环境有最佳的适应，但它们并不能充分利用它们的热环境。嗜热细菌和藻类在分类上与嗜热细菌和藻类有明显的相关性，两者之间的演化似乎是合理的。一种假设是，嗜热生物是遗留下来的，在地球比现在更热的时期，它们在地球上分布得更广泛。嗜热微生物可能与原菌形式有关，原菌形式通过许多突变和选择产生了嗜中菌和嗜冷菌形式。
The upper temperature for life has not yet been defined. At Yellowstone, some bacteria live and grow essentially at the boiling point. Since increased hydrostatic pressure may permit growth at even higher temperatures there seems to be no reason why bacteria could not live in nature at any temperature where there is liquid water. There is definitely an upper temperature for photosynthetic life, which seems to be at temperatures around 75[degree]C for procaryotic algae. Eu-caryotlc microorganisms are restricted to lower temperatures (less than 60[degree]C), and unicellular and multicellular animals to still lower temperatures (less than 50[degree]C). Blue-green algae living at a given temperature are optimally adapted to that temperature, even if it is near the upper limit for algal growth. These algae are not merely lower temperature forms which have extended their range but are forms which have actually evolved so that their temperature optima resemble their environmental temperatures. The molecular mechanism of ther-mophily is more likely to be related to the function and stability of cellular membranes than to the properties of specific macromolecules. In bacteria, where species have been studied with optima from 15[degree] to 70[degree]C, each organism has many enzymes which are stable at the optimum temperature of the organism, but not at higher temperatures. Organisms do not evolve proteins which are much more stable than they need to be. There may be some advantage to the organism in synthesizing denaturable proteins. There may be a relation between protein denaturability and current ideas concerning induced fit and allosteric interactions of enzymes. Although thermophlles grow somewhat faster at their optima than do mesophlles and psychrophiles at their optima, the increases are considerably less than would be predicted from the Arrhenlus equation. This suggests that thermophlles, even though optimally adapted to their environments, are not able to make full use of their thermal environment. The temperature optima of organisms are not easily changed by mutatloa Thermophilic bacteria and algae are clearly related taxonomically to mesophilic species, and it seems reasonable that one group is derived from the other. One hypothesis has been that thermophillc organisms are relicts, and were more widely distributed on the earth in times when it was hotter than it is today. Thermophillc microorganisms may be related to prlmorldal forms which gave rise, through many mutations followed by selection, to mesophillc and psychrophilic forms.