據(jù)新華社巴黎11月15日電,，法國國家科研中心15日發(fā)表公報(bào)說，該機(jī)構(gòu)研究人員通過對綠藻的觀測,，揭開了生物鐘“守時(shí)”的秘密。
為了揭開其中的奧秘,，法國國家科研中心巴紐爾斯海洋觀測站的研究人員對常見的單細(xì)胞綠藻進(jìn)行了24小時(shí)觀測,，并根據(jù)其體內(nèi)蛋白質(zhì)的生成數(shù)量繪制了曲線圖。結(jié)果他們發(fā)現(xiàn),，生物鐘只在某些特定時(shí)刻對光線敏感,，比如早上日出或晚間日落的時(shí)刻，在其他時(shí)間里,，生物鐘能夠“守時(shí)”是由于基因和蛋白質(zhì)的調(diào)節(jié)機(jī)制發(fā)揮作用。
在這種機(jī)制作用下,，生物體內(nèi)蛋白質(zhì)數(shù)量會(huì)定時(shí)增長或是消退,。比如基因A能夠生成蛋白質(zhì)，激發(fā)基因B的活性,，后者在被激活后同樣產(chǎn)生蛋白質(zhì),，讓基因A停止活動(dòng),，如此周而復(fù)始,，在24小時(shí)內(nèi),，生物體內(nèi)的蛋白質(zhì)數(shù)量隨著時(shí)間不斷變化,，會(huì)從零開始達(dá)到一定數(shù)量，然后又自動(dòng)消退,，從而使生物鐘發(fā)揮作用,。
這項(xiàng)成果發(fā)表在新一期的美國《科學(xué)公共圖書館計(jì)算生物學(xué)》雜志上。目前,，研究人員正在進(jìn)行深入研究,，希望驗(yàn)證這種機(jī)制是否適用于人類。（生物谷Bioon.com）
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生物谷推薦英文摘要：
PLoS Comput Biol 6(11): e1000990. doi:10.1371/journal.pcbi.1000990
Robustness of Circadian Clocks to Daylight Fluctuations: Hints from the Picoeucaryote Ostreococcus tauri
Quentin Thommen1,2,3,4, Benjamin Pfeuty1,2,3,4, Pierre-Emmanuel Morant1,2,3,4, Florence Corellou5,6, Fran?ois-Yves Bouget5,6, Marc Lefranc1,2,3,4*
1 Laboratoire de Physique des Lasers, Atomes, et Molécules, UFR de Physique, Université Lille 1, Villeneuve d'Ascq, France, 2 Centre National de la Recherche Scientifique, UMR 8523, Villeneuve d'Ascq Cedex, France, 3 Institut de Recherche Interdisciplinaire, Université Lille 1, Villeneuve d'Ascq, France, 4 Centre National de la Recherche Scientifique, USR 3078, Villeneuve d'Ascq, France, 5 Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Université Pierre and Marie Curie Paris 06, Banyuls/Mer, France, 6 Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Centre National de la Recherche Scientifique, Banyuls/Mer, France
The development of systemic approaches in biology has put emphasis on identifying genetic modules whose behavior can be modeled accurately so as to gain insight into their structure and function. However, most gene circuits in a cell are under control of external signals and thus, quantitative agreement between experimental data and a mathematical model is difficult. Circadian biology has been one notable exception: quantitative models of the internal clock that orchestrates biological processes over the 24-hour diurnal cycle have been constructed for a few organisms, from cyanobacteria to plants and mammals. In most cases, a complex architecture with interlocked feedback loops has been evidenced. Here we present the first modeling results for the circadian clock of the green unicellular alga Ostreococcus tauri. Two plant-like clock genes have been shown to play a central role in the Ostreococcus clock. We find that their expression time profiles can be accurately reproduced by a minimal model of a two-gene transcriptional feedback loop. Remarkably, best adjustment of data recorded under light/dark alternation is obtained when assuming that the oscillator is not coupled to the diurnal cycle. This suggests that coupling to light is confined to specific time intervals and has no dynamical effect when the oscillator is entrained by the diurnal cycle. This intringuing property may reflect a strategy to minimize the impact of fluctuations in daylight intensity on the core circadian oscillator, a type of perturbation that has been rarely considered when assessing the robustness of circadian clocks.
