細(xì)胞的程序性死亡是由基因控制的生物學(xué)事件，它在生物發(fā)育和維持機(jī)體內(nèi)環(huán)境穩(wěn)定的過程中有重要意義,。最常見的程序性死亡是細(xì)胞凋亡,，凋亡的過程會伴隨著一系列細(xì)胞形態(tài)改變和生化標(biāo)志。
以往對凋亡的研究都是針對真核細(xì)胞的,，而本文的研究者發(fā)現(xiàn),，在抗生素壓力下，大腸桿菌也會顯示出凋亡的特殊標(biāo)記,。包括細(xì)胞膜內(nèi)側(cè)的磷脂酰絲氨酸外翻,、染色質(zhì)凝集和DNA斷裂等。通過蛋白質(zhì)組學(xué)和基因組學(xué)分析,，研究人員發(fā)現(xiàn)多能性因子RecA是誘導(dǎo)這些凋亡表型的關(guān)鍵因子,。RecA能夠結(jié)合多肽序列，并將其引導(dǎo)到ClpXP蛋白酶附近,，通過ClpXP將其水解,。這項(xiàng)研究表明，在原核生物中,，或許也有與真核生物控制凋亡相似的機(jī)制來標(biāo)記和去除瀕死的細(xì)胞,。（生物谷 Bioon.com ）
doi:10.1016/j.molcel.2012.04.027
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Antibiotic-Induced Bacterial Cell Death Exhibits Physiological and Biochemical Hallmarks of Apoptosis
Daniel J. Dwyer, Diogo M. Camacho, Michael A. Kohanski, Jarred M. Callura, James J. Collins
Programmed cell death is a gene-directed process involved in the development and homeostasis of multicellular organisms. The most common mode of programmed cell death is apoptosis, which is characterized by a stereotypical set of biochemical and morphological hallmarks. Here we report that Escherichia coli also exhibit characteristic markers of apoptosis—including phosphatidylserine exposure, chromosome condensation, and DNA fragmentation—when faced with cell death-triggering stress, namely bactericidal antibiotic treatment. Notably, we also provide proteomic and genetic evidence for the ability of multifunctional RecA to bind peptide sequences that serve as substrates for eukaryotic caspases, and regulation of this phenotype by the protease, ClpXP, under conditions of cell death. Our findings illustrate that prokaryotic organisms possess mechanisms to dismantle and mark dying cells in response to diverse noxious stimuli and suggest that elaborate, multilayered proteolytic regulation of these features may have evolved in eukaryotes to harness and exploit their deadly potential.
