Scialdone Antonio, Mugford Sam T, Feike Doreen, Skeffington Alastair, Borrill Philippa, Graf Alexander, Smith Alison M, Howard Martin
Department of Computational and Systems Biology , John Innes Centre , Norwich , United Kingdom.
Elife. 2013 Jun 25;2:e00669. doi: 10.7554/eLife.00669.
Photosynthetic starch reserves that accumulate in Arabidopsis leaves during the day decrease approximately linearly with time at night to support metabolism and growth. We find that the rate of decrease is adjusted to accommodate variation in the time of onset of darkness and starch content, such that reserves last almost precisely until dawn. Generation of these dynamics therefore requires an arithmetic division computation between the starch content and expected time to dawn. We introduce two novel chemical kinetic models capable of implementing analog arithmetic division. Predictions from the models are successfully tested in plants perturbed by a night-time light period or by mutations in starch degradation pathways. Our experiments indicate which components of the starch degradation apparatus may be important for appropriate arithmetic division. Our results are potentially relevant for any biological system dependent on a food reserve for survival over a predictable time period. DOI:http://dx.doi.org/10.7554/eLife.00669.001.
白天在拟南芥叶片中积累的光合淀粉储备在夜间会随时间大致呈线性减少，以支持新陈代谢和生长。我们发现，淀粉储备减少的速率会根据黑暗开始时间和淀粉含量的变化进行调整，从而使储备几乎能精确维持到黎明。因此，产生这些动态变化需要在淀粉含量和预计黎明时间之间进行算术除法运算。我们引入了两种能够实现模拟算术除法的新型化学动力学模型。这些模型的预测在受到夜间光照期干扰或淀粉降解途径突变影响的植物中得到了成功验证。我们的实验表明，淀粉降解装置的哪些组成部分可能对适当的算术除法运算很重要。我们的结果可能与任何依赖食物储备在可预测时间段内存活的生物系统相关。DOI:http://dx.doi.org/10.7554/eLife.00669.001 。
