梭菌（Clostridium）是一類與人類關(guān)系十分密切的革蘭氏陽(yáng)性細(xì)菌,。理解梭菌適應(yīng)環(huán)境脅迫的機(jī)制,，無(wú)論是對(duì)在醫(yī)學(xué)上控制梭菌，還是在工業(yè)上利用梭菌，都具有十分重要的意義,。
梭菌屬中在工業(yè)上最廣泛應(yīng)用的種是丙酮丁醇梭菌,。丙酮丁醇梭菌的正常發(fā)酵過程要經(jīng)過產(chǎn)酸和產(chǎn)溶劑兩個(gè)階段，其中從產(chǎn)酸向產(chǎn)溶劑階段的過渡,，通常被認(rèn)為是該菌的一種解毒和適應(yīng)機(jī)制,。在這一轉(zhuǎn)換過程中，許多與脅迫應(yīng)答,、溶劑合成相關(guān)的蛋白會(huì)上調(diào)表達(dá),，而與氨基酸和蛋白質(zhì)合成相關(guān)的蛋白則會(huì)下調(diào)表達(dá)。
為了更好理解丙酮丁醇梭菌適應(yīng)環(huán)境脅迫的機(jī)制,，研究人員模擬自然界的進(jìn)化過程,，獲得了一株能夠在丁醇濃度提高50%的脅迫環(huán)境下正常生長(zhǎng)的突變株。采用比較蛋白質(zhì)組分析,，研究人員發(fā)現(xiàn)突變株中70%本應(yīng)在產(chǎn)溶劑階段上調(diào)或下調(diào)表達(dá)的差異蛋白,，在產(chǎn)酸期就提前上調(diào)或下調(diào)，在產(chǎn)溶劑期還會(huì)進(jìn)一步增大上調(diào)或下調(diào)的幅度,。這表明突變株進(jìn)化出了一種適應(yīng)環(huán)境脅迫的新策略,，即其解毒和適應(yīng)機(jī)制能夠更敏感地感知脅迫信號(hào)，提前啟動(dòng)并增強(qiáng)對(duì)關(guān)鍵蛋白的調(diào)控能力,，更快,、更靈活地調(diào)整細(xì)胞生理狀態(tài)，從而幫助突變株適應(yīng)了更具挑戰(zhàn)的環(huán)境,。
相關(guān)工作已于4月29日在線發(fā)表在美國(guó)化學(xué)會(huì)《蛋白質(zhì)組學(xué)研究》（Journal of Proteome Research）上,。該研究還建立了梭菌屬的第一張蛋白質(zhì)組參考圖譜，為梭菌屬的蛋白質(zhì)組學(xué)研究提供了基礎(chǔ)數(shù)據(jù),。
該研究由博士生毛紹名在李寅研究員和張延平博士的指導(dǎo)下完成,，研究得到973計(jì)劃、中國(guó)科學(xué)院知識(shí)創(chuàng)新工程重要方向項(xiàng)目和中國(guó)科學(xué)院創(chuàng)新團(tuán)隊(duì)國(guó)際合作伙伴計(jì)劃資助,。（生物谷Bioon.com）
生物谷推薦原文出處：
J. Proteome Res. DOI: 10.1021/pr9012078
Proteome Reference Map and Comparative Proteomic Analysis between a Wild Type Clostridium acetobutylicum DSM 1731 and its Mutant with Enhanced Butanol Tolerance and Butanol Yield
Shaoming Mao??§, Yuanming Luo??, Tianrui Zhang?, Jinshan Li?, Guanhui Bao?§, Yan Zhu?§, Zugen Chen, Yanping Zhang?, Yin Li*? and Yanhe Ma?
Institute of Microbiology, Chinese Academy of Sciences, Beijing, China, Graduate School of Chinese Academy of Sciences, Beijing, China, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China, and Department of Human Genetics, School of Medicine, University of California, Los Angeles, California 90095
The solventogenic bacterium Clostridium acetobutylicum is an important species of the Clostridium community. To develop a fundamental tool that is useful for biological studies of C. acetobutylicum, we established a high resolution proteome reference map for this species. We identified 1206 spots representing 564 different proteins by mass spectrometry, covering approximately 50% of major metabolic pathways. To better understand the relationship between butanol tolerance and butanol yield, we performed a comparative proteomic analysis between the wild type strain DSM 1731 and the mutant Rh8, which has higher butanol tolerance and higher butanol yield. Comparative proteomic analysis of two strains at acidogenic and solventogenic phases revealed 102 differentially expressed proteins that are mainly involved in protein folding, solvent formation, amino acid metabolism, protein synthesis, nucleotide metabolism, transport, and others. Hierarchical clustering analysis revealed that over 70% of the 102 differentially expressed proteins in mutant Rh8 were either upregulated (e.g., chaperones and solvent formation related) or downregulated (e.g., amino acid metabolism and protein synthesis related) in both acidogenic and solventogenic phase, which, respectively, are only upregulated or downregulated in solventogenic phase in the wild type strain. This suggests that Rh8 cells have evolved a mechanism to prepare themselves for butanol challenge before butanol is produced, leading to an increased butanol yield. This is the first report on the comparative proteome analysis of a mutant strain and a base strain of C. acetobutylicum. The fundamental proteomic data and analyses will be useful for further elucidating the biological mechanism of butanol tolerance and/or enhanced butanol production.
