據(jù)“每日科學(xué)”網(wǎng)站報(bào)道，科學(xué)家近日在號稱世上最頑強(qiáng)細(xì)菌的體內(nèi)中發(fā)現(xiàn)了他們一直找尋的化學(xué)抗氧化劑,。研究結(jié)果刊登在9月3日的《公共科學(xué)圖書館—綜合》（PLoS One）上。
(圖片來源：Uniformed Services University of the Health Sciences)
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完成人：邁克爾 戴利課題組/羅德尼 萊文課題組
實(shí)驗(yàn)室：美國軍隊(duì)衛(wèi)生服務(wù)大學(xué)病理學(xué)系,、三軍放射生物學(xué)研究所 美國國立衛(wèi)生研究院心肺血液研究所生物化學(xué)實(shí)驗(yàn)室
這種被稱為“耐輻射奇球菌（Deinococcus radiodurans）”的細(xì)菌發(fā)現(xiàn)于上世紀(jì)50年代,，其生命力異常頑強(qiáng)，就算是暴露在伽馬射線,、紫外線,、干燥環(huán)境或者其他通過產(chǎn)生活性氧來殺死細(xì)胞的試劑當(dāng)中，它依然能夠存活,。
在這項(xiàng)最新的研究中,，科學(xué)家在這種球菌的細(xì)胞提取液中檢測到含有二價(jià)錳的一些復(fù)合物，這些復(fù)合物可對純蛋白,、大腸桿菌以及人體細(xì)胞起到保護(hù)作用,，使其免受電離輻射的傷害。在受到伽馬射線的照射時(shí),，耐輻射奇球菌似乎會保存蛋白和DNA的分解物,，并與二價(jià)錳結(jié)合，將縮氨酸和正磷酸鹽進(jìn)行混合,，為強(qiáng)效活性氧清除系統(tǒng)提供原料。
可以預(yù)料的是,，耐輻射奇球菌這種新型高效的化學(xué)保護(hù)機(jī)制,，將為科學(xué)家研究如何應(yīng)對各種環(huán)境下的氧化應(yīng)激提供新思路。（生物谷Bioon.com）
生物谷推薦英文摘要：
PLoS ONE doi:10.1371/journal.pone.0012570
Small-Molecule Antioxidant Proteome-Shields in Deinococcus radiodurans
Michael J. Daly1*, Elena K. Gaidamakova1#, Vera Y. Matrosova1#, Juliann G. Kiang2, Risaku Fukumoto2, Duck-Yeon Lee3, Nancy B. Wehr3, Gabriela A. Viteri3, Barbara S. Berlett3, Rodney L. Levine3*
1 Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America, 2 Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America, 3 Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States of America
For Deinococcus radiodurans and other bacteria which are extremely resistant to ionizing radiation, ultraviolet radiation, and desiccation, a mechanistic link exists between resistance, manganese accumulation, and protein protection. We show that ultrafiltered, protein-free preparations of D. radiodurans cell extracts prevent protein oxidation at massive doses of ionizing radiation. In contrast, ultrafiltrates from ionizing radiation-sensitive bacteria were not protective. The D. radiodurans ultrafiltrate was enriched in Mn, phosphate, nucleosides and bases, and peptides. When reconstituted in vitro at concentrations approximating those in the D. radiodurans cytosol, peptides interacted synergistically with Mn2+ and orthophosphate, and preserved the activity of large, multimeric enzymes exposed to 50,000 Gy, conditions which obliterated DNA. When applied ex vivo, the D. radiodurans ultrafiltrate protected Escherichia coli cells and human Jurkat T cells from extreme cellular insults caused by ionizing radiation. By establishing that Mn2+-metabolite complexes of D. radiodurans specifically protect proteins against indirect damage caused by gamma-rays delivered in vast doses, our findings provide the basis for a new approach to radioprotection and insight into how surplus Mn budgets in cells combat reactive oxygen species.
