本文關(guān)鍵詞：生物鐘基因調(diào)節(jié)網(wǎng)絡(luò)隨機(jī)漲落誘導(dǎo)的節(jié)律振蕩研究　出處：《華中師范大學(xué)》2005年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 生物鐘 晝夜節(jié)律振蕩 超閾值 光噪聲 時(shí)間延遲 分子噪聲 相干共振 穩(wěn)固性

【摘要】：Smolen等人于2002年提出了果蠅時(shí)鐘蛋白節(jié)律振蕩的基因調(diào)節(jié)網(wǎng)絡(luò)兩變量模型。作為節(jié)律振蕩重要的控制因子,光通過(guò)提高磷酸化的TIM蛋白的衰減控制著時(shí)鐘基因的表達(dá)和果蠅的晝夜節(jié)律振蕩。我們把光噪聲引入到該確定性模型里,得到了果蠅節(jié)律振蕩的隨機(jī)動(dòng)力學(xué)模型。利用朗之萬(wàn)方程(Langevin Equation),我們首先研究了光噪聲對(duì)于時(shí)鐘蛋白晝夜節(jié)律振蕩的影響。當(dāng)光控參數(shù)超過(guò)分岔點(diǎn)略微遠(yuǎn)離振蕩區(qū)域時(shí),我們發(fā)現(xiàn)光的漲落可以誘導(dǎo)時(shí)鐘蛋白晝夜節(jié)律振蕩,并稱(chēng)之為超閾值的晝夜節(jié)律振蕩:當(dāng)光噪聲的強(qiáng)度較大或者較小時(shí),晝夜振蕩的節(jié)律性并不明顯;當(dāng)光噪聲強(qiáng)度取適當(dāng)大小時(shí),可以看到光噪聲誘導(dǎo)的隨機(jī)振蕩具有明顯的晝夜節(jié)律性。在某個(gè)噪聲強(qiáng)度下出現(xiàn)了這種相干的晝夜節(jié)律振蕩,由于它是一個(gè)被噪聲優(yōu)化的生物晝夜振蕩,所以反映了生物系統(tǒng)的一種重要的相干共振現(xiàn)象,信噪比和特征關(guān)聯(lián)時(shí)間的計(jì)算結(jié)果都確認(rèn)了我們的結(jié)論。結(jié)論表明了光的漲落在果蠅的晝夜節(jié)律振蕩中起著積極的作用。同時(shí)我們發(fā)現(xiàn)時(shí)間延遲可以控制相干共振的強(qiáng)度,在適當(dāng)?shù)臅r(shí)間延遲下,時(shí)鐘蛋白晝夜節(jié)律振蕩的相干性可以達(dá)到最大。 其次,我們單獨(dú)研究了分子噪聲對(duì)于晝夜振蕩子模型的影響。由于基因調(diào)節(jié)網(wǎng)絡(luò)中的分子數(shù)目很少,所以分子數(shù)目的漲落對(duì)于晝夜節(jié)律振蕩模型是重要的。為了估計(jì)分子噪聲影響,我們把確定性模型分解為基本的反應(yīng)項(xiàng),通過(guò)Gillespie介紹的算法來(lái)進(jìn)行分子噪聲的隨機(jī)模擬。我們發(fā)現(xiàn)分子噪聲同樣可以誘導(dǎo)超閾值的晝夜節(jié)律振蕩,并且誘導(dǎo)的晝夜振蕩非常穩(wěn)固,表現(xiàn)為基因調(diào)節(jié)網(wǎng)絡(luò)中時(shí)鐘蛋白質(zhì)分子數(shù)目只有數(shù)十個(gè)時(shí),系統(tǒng)仍然產(chǎn)生了較明顯的晝夜節(jié)律振蕩。 噪聲誘導(dǎo)的時(shí)鐘蛋白晝夜節(jié)律振蕩顯示了噪聲可以引導(dǎo)一個(gè)非線(xiàn)性系統(tǒng)
[Abstract]:Smolen et al in 2002 proposed a network model with two variables of Drosophila circadian oscillations in clock protein gene regulation. As an important factor to control the circadian oscillations, light by increasing the phosphorylation of TIM protein expression and attenuation control of Drosophila clock gene in the circadian oscillation. We put the light noise into the deterministic model and the stochastic the dynamics model of Drosophila circadian oscillations. Using the Langevin equation (Langevin Equation), we first studied the influence of light noise on circadian oscillations. When the light control parameter exceeds the bifurcation point slightly away from the oscillation region, we found that the light fluctuation can induce the circadian oscillations, called circadian oscillation super threshold: when light and large noise intensities is small, rhythmic circadian oscillation is not obvious; when the light intensity of noise proper size, You can see the random oscillation light induced by noise has obvious circadian rhythm. In a noise intensity appeared under this circadian coherent oscillation, because it is a noise optimization of circadian oscillation, so the biological system reflects an important coherent resonance phenomenon, calculate the signal-to-noise ratio and characteristics the results of correlation time confirmed our conclusions. The conclusion shows that the light fluctuation plays a positive role in the Drosophila circadian oscillations. At the same time we find that the time delay can control the coherence resonance intensity, at the appropriate time delay, the coherence of the circadian oscillations can reach the maximum.
Secondly, we study the effect of molecular noise on circadian oscillator model. Because the number of molecules in the gene regulation network is very few, so the fluctuation of the number of molecules is important for circadian oscillator model. In order to estimate the effect of molecular noise, we put the deterministic model into elementary reaction steps, random simulation is introduced through Gillespie the algorithm for molecular noise. We found that molecular noise could induce the circadian oscillation threshold, and induced circadian oscillations are extremely stable, performance for the number of clock gene regulatory protein molecules in the network only dozens of, the system still has obvious circadian oscillation.
The noise induced clock protein circadian rhythm oscillations show that noise can guide a nonlinear system

【學(xué)位授予單位】：華中師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2005
【分類(lèi)號(hào)】：Q811.213

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前3條

1 高雁;基于果蠅模式生物五味子醇甲改善睡眠的作用及其機(jī)制研究[D];黑龍江中醫(yī)藥大學(xué);2011年

2 王冬;影響果蠅睡眠相關(guān)因素的研究[D];黑龍江中醫(yī)藥大學(xué);2008年

3 李飛;基于果蠅為模式生物的五味子凍干粉改善睡眠作用的實(shí)驗(yàn)研究[D];黑龍江中醫(yī)藥大學(xué);2009年

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本文編號(hào)：1385077