饑餓時(shí),，枯草芽胞桿菌(Bacillus subtilis)進(jìn)入芽孢形成(sporulation)過程,，該過程持續(xù)幾個(gè)小時(shí)，最終形成已知的適應(yīng)性最強(qiáng)的細(xì)胞類型,，即芽孢,。研究人員證實(shí)在芽孢形成幾天之后，芽孢的RNA譜(RNA profile)是高度動(dòng)態(tài)變化的,。2011年12月29日,，該研究結(jié)果發(fā)表在《細(xì)胞》期刊上。
在高溫培育的老化芽孢中,，RNA含量在幾天之內(nèi)發(fā)生降解而全局性地下降,。這種降解可能是芽孢利用的一種策略以便促進(jìn)它進(jìn)入休眠。然而在低溫中保存的芽孢表現(xiàn)出不同的促進(jìn)轉(zhuǎn)錄的RNA譜,。
再者,，研究人員證實(shí)芽孢萌發(fā)(germination)受芽孢年齡、培育溫度和RNA狀態(tài)的影響,，這就意味著芽孢在被認(rèn)為是休眠狀態(tài)的時(shí)間里能夠獲得不同的特點(diǎn),。研究人員認(rèn)為，不同于當(dāng)前的想法,，進(jìn)入休眠需持續(xù)幾天,，在這當(dāng)中芽孢受環(huán)境的影響，并經(jīng)歷著影響它們萌發(fā)的相應(yīng)分子變化,。
綜上所述,，細(xì)菌芽孢在被認(rèn)為是休眠狀態(tài)的時(shí)間里,，它的RNA譜是動(dòng)態(tài)變化的；在高溫培育的老化芽孢的RNA含量因受到降解而下降,；低溫保存的芽孢在芽孢形成后幾天,，發(fā)生顯著的RNA轉(zhuǎn)錄；芽孢萌發(fā)受芽孢年齡,、培育時(shí)間和RNA狀態(tài)的影響,。(生物谷：towersimper編譯)
doi:10.1016/j.cell.2011.11.059
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RNA Dynamics in Aging Bacterial Spores
Einat Segev, Yoav Smith, Sigal Ben-Yehuda
Upon starvation, the bacterium Bacillus subtilis enters the process of sporulation, lasting several hours and culminating in formation of a spore, the most resilient cell type known. We show that a few days following sporulation, the RNA profile of spores is highly dynamic. In aging spores incubated at high temperatures, RNA content is globally decreased by degradation over several days. This degradation might be a strategy utilized by the spore to facilitate its dormancy. However, spores kept at low temperature exhibit a different RNA profile with evidence supporting transcription. Further, we demonstrate that germination is affected by spore age, incubation temperature, and RNA state, implying that spores can acquire dissimilar characteristics at a time they are considered dormant. We propose that, in contrast to current thinking, entering dormancy lasts a few days, during which spores are affected by the environment and undergo corresponding molecular changes influencing their emergence from quiescence.
