本文選題：Bergmanns’rule　切入點：果蠅　出處：《浙江大學》2016年博士論文　論文類型：學位論文

【摘要】：環(huán)境因素對個體發(fā)育的影響是一個經(jīng)久不衰的研究命題,在眾多因素中,氣候的變更,溫度的變化無處不在,它對動物個體發(fā)育乃至種群進化產(chǎn)生巨大的影響。19世紀,德國生物學家Carl Bergmann發(fā)現(xiàn),動物個體的體型與生存地區(qū)緯度呈正相關關系,緯度越高,溫度越寒冷的地區(qū),動物個體體型越大,緯度越低,溫度越溫暖的地區(qū),動物個體體型越小。這就是著名的Bergmann's rule,它總結了生存溫度對溫血動物體型影響的一般規(guī)律。在非脊椎動物中,動物體形與溫度呈負相關的關系更加普遍存在,我們稱之為溫度體形規(guī)律(Temperature-Size Rule,TSR)。從19世紀初開始,人們對各種動物進行研究和考察,嘗試解釋溫度影響動物體型的原因,至今我們對其分子細胞機制仍然知之甚少。模式動物果蠅是用來研究溫度影響體型規(guī)律的良好載體,早在1940年,人們已經(jīng)開始利用果蠅研究溫度影響體型的規(guī)律,果蠅在其適宜的生存溫度范圍內(nèi),成熟體的體型大小具有強烈的溫度可塑性,比如低溫環(huán)境(18℃)下飼養(yǎng)的果蠅的體型比在高溫環(huán)境(25℃)下飼養(yǎng)的果蠅大10%左右。果蠅幼蟲階段是發(fā)育積累并決定成熟體體型大小的決定性階段,于是我們主要研究幼蟲的發(fā)育機制。果蠅幼蟲與成蟲一樣,具有豐富的感知系統(tǒng),包括化學感知、機械感知、溫度感知等。在幼蟲外周分布著豐富的初級感知神經(jīng)元,它們投射到腦中央神經(jīng)元形成簡單且功能齊全的神經(jīng)網(wǎng)絡。初級感知神經(jīng)元是動物感知外界環(huán)境因素(溫度)的必經(jīng)之路,我們以研究果蠅幼蟲的溫度感知神經(jīng)系統(tǒng)為立足點,以人工操控神經(jīng)元的興奮性為手段,結合基本的細胞分子檢測方法研究溫度影響個體發(fā)育的機制。果蠅胰島素是調(diào)節(jié)幼蟲發(fā)育的關鍵分子之一并且具有物種保守性,主要的幾個果蠅胰島素由胰島素生成細胞IPCs (insulin producing cells),一個分泌性神經(jīng)元,合成與分泌。我們發(fā)現(xiàn)阻斷IPCs可以消除低溫促進幼蟲體型增大的影響,而激活IPCs則可以促進幼蟲體型增加,通過在體鈣成像實驗,我們發(fā)現(xiàn)低溫刺激可以興奮IPCs,通過熒光定量PCR,免疫組織化學和免疫印記實驗,我們發(fā)現(xiàn)低溫可以促進其中的果蠅胰島素RNA的合成和胰島素的分泌。說明IPCs做為一個發(fā)育調(diào)控關鍵細胞和一個低溫興奮性神經(jīng)元在低溫促進幼蟲發(fā)育過程中的重要性。更進一步,我們通過篩選得到一個標記果蠅頭部神經(jīng)元的11216-Gal4品系,在體鈣成像實驗的數(shù)據(jù)表明,低溫刺激可以激活11216-Gal4標記的神經(jīng)元,通過鑒定和比對,我們確認這些神經(jīng)元為幼蟲的初級冷覺感知神經(jīng)元。我們利用GRASP (GFP reconstitution across synaptic partners)技術,證明這些11216-Gal4標記的初級冷覺感知神經(jīng)元的軸突與IPCs的樹突形成物理上的突觸聯(lián)系；利用光遺傳結合鈣成像的方法,我們發(fā)現(xiàn)激活11216-Gal4標記的初級冷覺感知神經(jīng)元可以激活IPCs,說明這兩群神經(jīng)元形成功能性的神經(jīng)環(huán)路。同時我們發(fā)現(xiàn),激活11216-Gal4標記的初級冷覺感知神經(jīng)元可以促進IPCs中的果蠅胰島素RNA的合成和胰島素的分泌,并且導致果蠅的體型增大,很好的再現(xiàn)了低溫刺激的效果。我們的研究揭示了冷覺信號刺激胰島素合成分泌并促進個體生長的神經(jīng)信號傳遞通路,為TSR提供了一個神經(jīng)環(huán)路水平的機制性解釋,也為Bergmann's rule的解釋提供了借鑒。
[Abstract]:The environmental factor is a research topic of enduring influence on individual development, among other factors, climate change, temperature change is everywhere, it has great influence on the.19 century animal ontogeny and population evolution, the German biologist Carl Bergmann discovered that size and survival latitude is positively related to the individual animal the temperature is, the higher the latitude, the cold area, the individual animal bigger in lower latitude area, temperature is warm, the smaller animal individual. This is the famous Bergmann's rule, its general rule summarizes the influence of temperature on the survival of warm blooded animal size. In vertebrates, the animal body with temperature. The negative correlation is more prevalent, we call the body temperature regulation (Temperature-Size Rule, TSR). From the beginning of nineteenth Century, people study and investigation of all kinds of animal, try Explain the temperature influence reasons of animal body, so far we on the molecular and cellular mechanisms are still poorly understood. Animal model of Drosophila is a good carrier to study the influence of temperature size rule, in early 1940, people have begun to use the influence of temperature on size of fruit flies, flies its survival in the suitable temperature range, the size of mature body the temperature has a strong plasticity, such as low temperature (18 DEG C) were smaller than Drosophila under high temperature (25 DEG C) about feeding 10%. Fruit fly Drosophila larvae stage of development is accumulated and decisive stage of mature body size, so we mainly study the developmental mechanism of larvae of Drosophila larvae. And as adults, with rich perception system, including chemical sensing, mechanical sensing, temperature sensing. In the primary distribution of peripheral larvae to perceive God rich by yuan, their investment Shot to the brain central neurons form neural network is simple and functional. The primary sensory neurons is animal perception of external environmental factors (temperature) of the temperature sensing we the only way which must be passed, nervous system of Drosophila larvae as the starting point, the excitability of neurons in the artificial control means, combined with the basic research of cellular and molecular mechanism of temperature effect detection method the ontogeny of Drosophila. Insulin is one of the key molecules regulating larval development and species conservation, several major Drosophila insulin producing cells by insulin IPCs (insulin producing cells), a secretory neuron, synthesis and secretion. We found that blocking the IPCs can eliminate the effect of low temperature effects of larval size increased, while the activation of IPCs can be to promote the increase in the size of larvae, the imaging experiment of body calcium, we found that low temperature stimulation can be excited by IPCs. Light quantitative PCR, immunohistochemistry and Western blotting experiments, we found that low temperature can promote the synthesis and secretion of insulin in the Drosophila insulin RNA. IPCs as a key developmental control cell and a low temperature low temperature promote excitatory neurons in the larval developmental importance process. Further, we obtained through screening the 11216-Gal4 strain of a Drosophila head marker of neurons, that in body calcium imaging experiment data, low temperature stimulation can activate 11216-Gal4 labeled neurons, through the identification and comparison, we confirmed that these neurons of primary sensory neurons of larvae. We use GRASP (GFP reconstitution across synaptic partners) technology, that axons and the primary IPCs cryesthesia sensory neurons of these 11216-Gal4 markers for dendritic synapses physically; using light calcium combined with genetic The imaging method, we found that the initial activation of 11216-Gal4 labeled neurons cold perception can activate IPCs, indicating that the two groups of neurons form functional neural circuits. At the same time, we found that the primary sensory neurons labeled by 11216-Gal4 activation of IPCs can promote the synthesis and secretion of insulin in the fruit fly RNA insulin, and increase the size of Drosophila melanogaster well, the reproduction of the low temperature stimulation effect. Our study reveals the cold stimulation of insulin synthesis and secretion and promote individual growth of neural signal pathway, provides a mechanism of a neural circuit level explanation for TSR, but also provide a reference for the interpretation of rule Bergmann's.

【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：Q43

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