Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, CH A1 375 Station 6, Lausanne, CH-1015, Switzerland.
Environ Microbiol Rep. 2014 Dec;6(6):756-66. doi: 10.1111/1758-2229.12200. Epub 2014 Sep 8.
The genus Desulfotomaculum, belonging to the Firmicutes, comprises strictly anaerobic and endospore-forming bacteria capable of dissimilatory sulfate reduction. These microorganisms are metabolically versatile and are widely distributed in the environment. Spore formation allows them to survive prolonged environmental stress. Information on the mechanism of sporulation in Desulfotomaculum species is scarce. Herein, this process was probed from a genomic standpoint, using the Bacillus subtilis model system as a reference and clostridial sporulation for comparison. Desulfotomaculum falls somewhere in between the Bacillus and Clostridium in terms of conservation of sporulation proteins. Furthermore, it showcased the conservation of a core regulatory cascade throughout genera, while uncovering variability in the initiation of sporulation and the structural characteristics of spores from different genera. In particular, while in Clostridium species sporulation is not initiated by a phosphorelay, Desulfotomaculum species harbour homologues of the B. subtilis proteins involved in this process. Conversely, both Clostridium and Desulfotomaculum species conserve very few B. subtilis structural proteins, particularly those found in the outer layers of the spore. Desulfotomaculum species seem to share greater similarity to the outer layers of Clostridium difficile.
脱硫单胞菌属属于厚壁菌门，包含严格厌氧和产芽孢的细菌，能够进行异化型硫酸盐还原。这些微生物具有代谢多样性，广泛分布于环境中。芽孢形成使它们能够在长时间的环境压力下存活。关于脱硫单胞菌属芽孢形成机制的信息很少。本文从基因组的角度探讨了这个过程，以枯草芽孢杆菌模型系统为参考，以梭菌的芽孢形成作为比较。就芽孢形成蛋白的保守性而言，脱硫单胞菌在芽孢杆菌和梭菌之间处于中间位置。此外，它展示了整个属中核心调控级联的保守性，同时揭示了不同属之间芽孢形成的起始和芽孢结构特征的可变性。特别是，在梭菌中，芽孢形成不是由磷酸接力启动的，而脱硫单胞菌属则拥有参与该过程的枯草芽孢杆菌蛋白的同源物。相反，梭菌和脱硫单胞菌属都很少保留枯草芽孢杆菌的结构蛋白，特别是那些存在于芽孢外层的蛋白。脱硫单胞菌属似乎与艰难梭菌的外层有更大的相似性。
