Molecular Microbiology and Immunology Department, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
Space Center, Houston, TX, 77058, USA.
Environ Microbiol Rep. 2022 Aug;14(4):679-685. doi: 10.1111/1758-2229.13078. Epub 2022 Jul 19.
As human activity in space continues to increase, understanding how biological assets respond to spaceflight conditions is becoming more important. Spaceflight conditions include exposure to ionizing radiation, microgravity, spacecraft vibrations and hypervelocity; all of which can affect the viability of biological organisms. Previous studies have shown that melanin-producing fungi are capable of surviving the vacuum of space and Mars-simulated conditions in Low Earth Orbit. This survival has been associated in part with the protective effects of melanin, but a comparison of fungal viability in the presence or absence of melanin following spaceflight has never been tested. In this study, we evaluated the protective effects of melanin by comparing the viability of melanized and non-melanized clones of Cryptococcus neoformans yeasts following a roundtrip to the International Space Station. Yeast colonies were placed inside two MixStix silicone tubes; one stayed on Earth and the other was transported inside for 29 days before returning to Earth. Post-flight analysis based on colony-forming unit numbers shows that melanized yeast viability was 50% higher than non-melanized yeasts, while no difference was observed between the Earth-bound control samples. The results suggest that fungal melanin could increase the lifespan of biological assets in space.
随着人类在太空的活动不断增加，了解生物资产如何应对太空飞行条件变得越来越重要。太空飞行条件包括暴露于电离辐射、微重力、航天器振动和超高速；所有这些都会影响生物机体的生存能力。先前的研究表明，产生黑色素的真菌能够在太空中生存下来，并在近地轨道上模拟火星条件。这种生存部分与黑色素的保护作用有关，但在太空飞行后，黑色素存在或不存在的情况下，真菌生存能力的比较从未被测试过。在这项研究中，我们通过比较往返国际空间站后新型隐球菌酵母的黑色素化和非黑色素化克隆的生存能力，评估了黑色素的保护作用。酵母菌落被放置在两个 MixStix 硅酮管内；一个留在地球上，另一个在太空飞行 29 天后被送回地球。基于集落形成单位数量的飞行后分析表明，黑色素化酵母的生存能力比非黑色素化酵母高 50%，而在地球上的对照样本之间没有观察到差异。结果表明，真菌黑色素可能会增加太空生物资产的寿命。
