Survival of yeast spores in hypervelocity impact events up to velocities of 7.4 km s-1
Survival of yeast spores in hypervelocity impact events up to velocities of 7.4 km s-1
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DOI：
10.1016/j.icarus.2012.10.035
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发表时间：
2013-01-01
期刊：
影响因子：
3.2
通讯作者：
Cole, M. J.
中科院分区：
文献类型：
--
作者：
Price, M. C.;Solscheid, C.;Cole, M. J.
我们报告了孢子形式的酵母和成熟培养物在撞击速度从1到7.4 km s（-1）的超高速撞击中的生存能力，对应于估计的峰值冲击压力类似于43 GPa。来自酵母菌株（BY4743）的孢子缺乏生产尿嘧啶所需的酶，使用轻型气枪将其射入水中（模拟从太空对海洋的影响）。然后将水回收并过滤，并将所得截留液和滤液进行培养，以确定残余孢子的活力和存活率。在所有撞击速度下的回收样品中都发现了酵母生长（确认来自原始样品，因为它具有相同的酶缺乏症），尽管在较高的速度下数量较少。在1 km s（-1）时，存活率接近50%，在7.4 km s（-1）时，存活率接近10%(-3)%。这遵循了之前在极端冲击负荷下微生物生命和孢子存活的研究中观察到的模式，在低峰值冲击压力下有合理的存活，在GPa范围内（这里在2到10 GPa之间）的临界冲击压力以上有更严重的致命性。这些结果是在极端冲击下生存的一般模型的背景下解释的，并且与生源说和岩石生源说的假设有关，表明在空间转移过程中的极端冲击不一定是无菌的。(C) 2012爱思唯尔公司版权所有。
We report on the survivability in hypervelocity impacts of yeast in spore form, and as mature cultures, at impact velocities from 1 to 7.4 km s(-1), corresponding to an estimated peak shock pressure of similar to 43 GPa. Spores from a yeast strain (BY4743), deficient in an enzyme required for uracil production, were fired into water (to simulate oceanic impact from space) using a light gas gun. The water was then retrieved and filtered and the resulting retentate and filtrate cultured to determine viability and survival rates of remnant spores. Yeast growth (confirmed as coming from the original sample as it had the same enzyme deficiency) was found in recovered samples at all impact speeds, albeit in smaller quantities at the higher speeds. The survival probabilities were measured as similar to 50% at 1 km s(-1), falling to similar to 10(-3)% at 7.4 km s(-1). This follows the pattern observed in previous work on survival of microbial life and spores exposed to extreme shock loading, where there is reasonable survival at low peak shock pressures with more severe lethality above a critical shock pressure at the GPa scale (here between 2 and 10 GPa). These results are explained in the context of a general model for survival against extreme shock and are relevant to the hypotheses of panspermia and litho-panspermia, showing that extreme shocks during transfer across space are not necessarily sterilising. (C) 2012 Elsevier Inc. All rights reserved.