Department of Biology Houston, Texas Southern University, Houston, TX, USA.
Appl Microbiol Biotechnol. 2010 Jan;85(4):885-91. doi: 10.1007/s00253-009-2237-8. Epub 2009 Oct 22.
For unsuspecting bacteria, the difference between life and death depends upon efficient and specific responses to various stressors. Facing a much larger world, microbes are invariably challenged with ever-changing environments where temperature, pH, chemicals, and nutrients are in a constant state of flux. Only those that are able to rapidly reprogram themselves and express subsets of genes needed to overcome the stress will survive and outcompete neighboring microbes. Recently, low shear stress, emulating microgravity (MG) experienced in space, has been characterized in a number of microorganisms including fungi and prokaryotes ranging from harmless surrogate organisms to bona fide pathogens. Interestingly, MG appears to induce a plethora of effects ranging from enhanced pathogenicity in several Gram-negative enterics to enhanced biofilm formation. Furthermore, MG-exposed bacteria appeared better able to handle subsequent stressors including: osmolarity, pH, temperature, and antimicrobial challenge while yeast exhibited aberrant budding post-MG-exposure. This review will focus on MG-induced alterations of virulence in various microbes with the emphasis placed on bacteria.
对于毫无防备的细菌来说，生死取决于其能否对各种压力源做出高效且特异性的反应。面对一个更大的世界，微生物总是面临着不断变化的环境，其中温度、pH 值、化学物质和营养物质处于持续变化的状态。只有那些能够迅速自我重新编程并表达克服压力所需的基因子集的微生物才能存活下来，并在与邻近微生物的竞争中胜出。最近，已经在包括真菌和原核生物在内的许多微生物中对模拟太空中微重力（MG）的低切变应力进行了描述，这些微生物的范围从无害的替代生物到真正的病原体。有趣的是，MG 似乎会引起多种影响，从几种革兰氏阴性肠道细菌的致病性增强到生物膜形成的增强。此外，暴露于 MG 的细菌似乎更能应对随后的压力源，包括：渗透压、pH 值、温度和抗菌挑战，而酵母在 MG 暴露后表现出异常的出芽现象。这篇综述将重点介绍 MG 对各种微生物毒力的诱导改变，重点是细菌。
