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首页> 外文期刊>Applied Microbiology >Effects of Mn and Fe Levels on Bacillus subtilis Spore Resistance and Effects of Mn2+, Other Divalent Cations, Orthophosphate, and Dipicolinic Acid on Protein Resistance to Ionizing Radiation
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Effects of Mn and Fe Levels on Bacillus subtilis Spore Resistance and Effects of Mn2+, Other Divalent Cations, Orthophosphate, and Dipicolinic Acid on Protein Resistance to Ionizing Radiation

机译：锰和铁水平对枯草芽孢杆菌孢子抗性的影响以及锰，其他二价阳离子，正磷酸盐和双吡啶甲酸对蛋白质对电离辐射的抗性的影响

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Spores of Bacillus subtilis strains with (wild type) or without (α~(?)β~(?)) most DNA-binding α/β-type small, acid-soluble proteins (SASP) were prepared in medium with additional MnCl_(2) concentrations of 0.3 μM to 1 mM. These haploid spores had Mn levels that varied up to 180-fold and Mn/Fe ratios that varied up to 300-fold. However, the resistance of these spores to desiccation, wet heat, dry heat, and in particular ionizing radiation was unaffected by their level of Mn or their Mn/Fe ratio; this was also the case for wild-type spore resistance to hydrogen peroxide (H_(2)O_(2)). However, α~(?)β~(?) spores were more sensitive to H_(2)O_(2) when they had high Mn levels and a high Mn/Fe ratio. These results suggest that Mn levels alone are not essential for wild-type bacterial spores' extreme resistance properties, in particular ionizing radiation, although high Mn levels sensitize α~(?)β~(?) spores to H_(2)O_(2), probably by repressing expression of the auxiliary DNA-protective protein MrgA. Notably, Mn~(2+) complexed with the abundant spore molecule dipicolinic acid (DPA) with or without inorganic phosphate was very effective at protecting a restriction enzyme against ionizing radiation in vitro , and Ca~(2+) complexed with DPA and phosphate was also very effective in this regard. These latter data suggest that protein protection in spores against treatments such as ionizing radiation that generate reactive oxygen species may be due in part to the spores' high levels of DPA conjugated to divalent metal ions, predominantly Ca~(2+), much like high levels of Mn~(2+) complexed with small molecules protect the bacterium Deinococcus radiodurans against ionizing radiation.
机译：在具有额外MnCl_（）的培养基中制备具有（野生型）或不具有（α〜（？）β〜（？））大多数DNA结合型α/β型小酸溶蛋白（SASP）的枯草芽孢杆菌菌株的孢子。 2）浓度为0.3μM至1 mM。这些单倍体孢子的Mn含量最多可变化180倍，而Mn / Fe比例最多可变化300倍。但是，这些孢子对干燥，湿热，干热，特别是电离辐射的抵抗力不受其锰含量或锰/铁比的影响。野生型孢子对过氧化氢（H_（2）O_（2））的抵抗力也是如此。然而，当α〜（？）β〜（？）孢子具有较高的Mn含量和较高的Mn / Fe比时，它们对H_（2）O_（2）更敏感。这些结果表明，尽管高锰水平会使α〜（？）β〜（？）孢子对H_（2）O_（2）敏感，但单独的Mn水平对于野生型细菌孢子的极端抗性，尤其是电离辐射并不是必不可少的。 ），可能是通过抑制辅助DNA保护蛋白MrgA的表达来实现的。值得注意的是，有或没有无机磷酸盐的Mn〜（2+）与丰富的孢子分子二吡啶甲酸（DPA）的复合在保护限制性内切酶免于电离辐射方面非常有效，而与DPA和磷酸盐的Ca〜（2+）的复合非常有效。在这方面也非常有效。后面的数据表明，孢子中的蛋白质对诸如产生活性氧的电离辐射等处理的保护作用可能部分是由于孢子中高水平的DPA与二价金属离子共轭，主要是Ca〜（2+），与高浓度的Mn〜（2+）与小分子复合可保护细菌Deinococcus radiodurans免受电离辐射。

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