Knox Benjamin P, Blachowicz Adriana, Palmer Jonathan M, Romsdahl Jillian, Huttenlocher Anna, Wang Clay C C, Keller Nancy P, Venkateswaran Kasthuri
Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA; Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, USA.
mSphere. 2016 Oct 26;1(5). doi: 10.1128/mSphere.00227-16. eCollection 2016 Sep-Oct.
One mission of the Microbial Observatory Experiments on the International Space Station (ISS) is to examine the traits and diversity of fungal isolates to gain a better understanding of how fungi may adapt to microgravity environments and how this may affect interactions with humans in a closed habitat. Here, we report an initial characterization of two isolates, ISSFT-021 and IF1SW-F4, of collected from the ISS and a comparison to the experimentally established clinical isolates Af293 and CEA10. Whole-genome sequencing of ISSFT-021 and IF1SW-F4 showed 54,960 and 52,129 single nucleotide polymorphisms, respectively, compared to Af293, which is consistent with observed genetic heterogeneity among sequenced isolates from diverse clinical and environmental sources. Assessment of growth characteristics, secondary metabolite production, and susceptibility to chemical stresses revealed no outstanding differences between ISS and clinical strains that would suggest special adaptation to life aboard the ISS. Virulence assessment in a neutrophil-deficient larval zebrafish model of invasive aspergillosis revealed that both ISSFT-021 and IF1SW-F4 were significantly more lethal than Af293 and CEA10. Taken together, these genomic, , and analyses of two strains isolated from the ISS provide a benchmark for future investigations of these strains and for continuing research on specific microbial isolates from manned space environments. As durations of manned space missions increase, it is imperative to understand the long-term consequence of microbial exposure on human health in a closed human habitat. To date, studies aimed at bacterial and fungal contamination of space vessels have highlighted species compositions biased toward hardy, persistent organisms capable of withstanding harsh conditions. In the current study, we assessed traits of two independent strains isolated from the International Space Station. Ubiquitously found in terrestrial soil and atmospheric environments, is a significant opportunistic fungal threat to human health, particularly among the immunocompromised. Using two well-known clinical isolates of as comparators, we found that both ISS isolates exhibited normal growth and chemical stress tolerance yet caused higher lethality in a vertebrate model of invasive disease. These findings substantiate the need for additional studies of physical traits and biological activities of microbes adapted to microgravity and other extreme extraterrestrial conditions.
国际空间站（ISS）上的微生物观测实验的一项任务是研究真菌分离株的特性和多样性，以便更好地了解真菌如何适应微重力环境，以及这可能如何影响在封闭栖息地中与人类的相互作用。在此，我们报告了从国际空间站收集的两个分离株ISSFT - 021和IF1SW - F4的初步特征，并与实验确定的临床分离株Af293和CEA10进行了比较。与Af293相比，ISSFT - 021和IF1SW - F4的全基因组测序分别显示出54,960和52,129个单核苷酸多态性，这与从不同临床和环境来源测序的曲霉菌株中观察到的遗传异质性一致。对生长特性、次级代谢产物产生以及对化学胁迫的敏感性的评估表明，国际空间站菌株和临床菌株之间没有显著差异表明其对国际空间站上生活的特殊适应性。在中性粒细胞缺陷的侵袭性曲霉病幼虫斑马鱼模型中的毒力评估表明，ISSFT - 021和IF1SW - F4的致死性均显著高于Af293和CEA10。综上所述，对从国际空间站分离的两个曲霉菌株的这些基因组、生长特性和毒力分析为这些菌株的未来研究以及对载人空间环境中特定微生物分离株的持续研究提供了基准。随着载人航天任务持续时间的增加，了解在封闭的人类栖息地中微生物暴露对人类健康的长期影响至关重要。迄今为止，针对航天器细菌和真菌污染的研究突出了物种组成偏向于能够承受恶劣条件的顽强、持久的生物体。在当前研究中，我们评估了从国际空间站分离的两个独立曲霉菌株的特性。曲霉菌在陆地土壤和大气环境中普遍存在，是对人类健康的重大机会性真菌威胁，尤其是在免疫功能低下者中。使用两个著名的临床曲霉菌分离株作为对照，我们发现两个国际空间站分离株均表现出正常的曲霉菌生长和化学胁迫耐受性，但在侵袭性疾病的脊椎动物模型中导致更高的致死率。这些发现证实了需要对适应微重力和其他极端外星条件的微生物的物理特性和生物活性进行更多研究。
