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首页> 外文期刊>The Journal of Experimental Biology >Oxygen in egg masses: interactive effects of temperature, age, and egg-mass morphology on oxygen supply to embryos
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Oxygen in egg masses: interactive effects of temperature, age, and egg-mass morphology on oxygen supply to embryos

机译：鸡蛋中的氧气：温度，年龄和蛋质量形态对胚胎供氧的交互作用

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Embryos of many marine invertebrates are encased in gelatinous masses for part or all of development. Because gel and intervening embryos retard oxygen flux, such a life-history mode profoundly affects partial pressures of metabolic gases surrounding embryos. However, little is known about relationships between egg-mass structure and the opportunities and constraints imposed on structure by metabolic gas transport. We examined the effects of four factors (temperature, embryo age, embryo density and egg-mass size) on the metabolism of egg masses using both natural egg masses of a nudibranch and artificial egg masses made from sand dollar embryos and low-melting point agarose. Both temperature and embryo age strongly affected metabolic rates of nudibranch embryos. For embryos of a given age (stage), rates of oxygen consumption roughly doubled between 12 and 21 degrees C; from early cleavage to the veliger stage, consumption rose two- to fourfold, depending on temperature. Oxygen profiles in egg masses showed that advanced embryonic age, and to a lesser extent high temperature, both led to steeper oxygen gradients into egg masses. Egg masses containing advanced embryos at 21 degrees C had very low central oxygen levels. Small-diameter artificial masses (2 mm diameter) had virtually no internal oxygen gradients regardless of embryo density or temperature, while medium (4 mm) and large diameter (10 mm) artificial masses had oxygen profiles that depended strongly and interactively on embryo density and temperature. Together, our data on natural and artificial egg masses suggest that (i) multiple factors have strong effects on metabolic rate; (ii) rates of oxygen transport are relatively invariant with temperature in simple, artificial systems but may vary more strongly with temperature in natural egg masses; and (iii) the four factors--temperature, embryo age, embryo density and egg-mass size--interact in important ways bearing on egg mass design. A simple mathematical model is developed to provide a quantitative means of estimating primary and interactive effects of the different factors. We also show that in T. diomedea the gel itself is the main barrier to oxygen transport into egg masses, and that the metabolic activity of embryos increases substantially when embryos are artificially released from the capsules that contain them within the gel mass.
机译：许多海洋无脊椎动物的胚胎被包裹在凝胶状块中，以进行部分或全部发育。由于凝胶和介入的胚胎会阻碍氧气通量，因此这种生命历史模式会深刻影响胚胎周围代谢气体的分压。但是，人们对蛋的质量结构与代谢气体运输对结构施加的机会和限制之间的关系知之甚少。我们使用裸using的天然卵块和由沙钱胚和低熔点琼脂糖制成的人工卵块，研究了四个因素（温度，胚龄，胚密度和卵块大小）对卵块代谢的影响。 。温度和胚胎年龄都强烈影响裸udi分支胚胎的代谢率。对于给定年龄（阶段）的胚胎，耗氧率在12到21摄氏度之间大约翻了一番。从早期卵裂到香根草阶段，根据温度的不同，食用量增加了2到4倍。鸡蛋块中的氧气分布图表明，晚期胚胎年龄和较高程度的高温都导致进入鸡蛋块的氧气梯度变大。在21摄氏度时，含有高级胚胎的卵块的中央氧水平非常低。无论胚胎密度或温度如何，小直径人造块（直径2毫米）实际上都没有内部氧梯度，而中等直径（4毫米）和大直径（10毫米）人造块的氧分布强烈且交互地依赖于胚胎密度和温度。温度。总之，我们关于天然和人造鸡蛋质量的数据表明：（i）多种因素对代谢率有很大影响; （ii）在简单的人工系统中，氧气的输送速率随温度而相对不变，但在天然蛋块中氧气的迁移率可能随温度变化更大; （iii）温度，胚胎年龄，胚胎密度和卵质量大小这四个因素相互作用，对卵的质量设计有重要影响。开发了一个简单的数学模型，以提供一种定量方法来估算不同因素的主要影响和交互作用。我们还表明，在T. diomedea中，凝胶本身是氧气转运到卵团中的主要障碍，当从凝胶团中包含它们的胶囊中人工释放胚时，胚的代谢活性大大提高。

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