Dimethylsulfoxide (DMSO) has long been known to support anaerobic respiration in a few species of basically aerobic extremely halophilic euryarchaea living in hypersaline lakes. Recently, it has also been shown to be utilized as an additional electron acceptor in basically anaerobic sulfur-reducing haloarchaea. Here we investigated whether haloarchaea would be capable of anaerobic respiration with other two sulfoxides, methionine sulfoxide (MSO) and tetramethylene sulfoxide (TMSO). For this, anaerobic enrichment cultures were inoculated with sediments from hypersaline salt and soda lakes in southwestern Siberia and southern Russia. Positive enrichments were obtained for both MSO and TMSO with yeast extract but not with formate or acetate as the electron donor. Two pure cultures obtained from salt lakes, either with MSO or TMSO, were obligate anaerobes closely related to sulfur-reducing Halanaeroarchaeum sulfurireducens, although the type strain of this genus was unable to utilize any sulfoxides. Two pure cultures isolated from soda lakes were facultatively anaerobic alkaliphilic haloarchaea using O₂, sulfur and sulfoxides as the electron acceptors. One isolate was identical to the previously described sulfur-reducing Natrarchaeobaculum sulfurireducens, while another one, enriched at lower alkalinity, is forming a new species in the genus Halobiforma. Since all isolates enriched with either MSO or TMSO were able to respire all three sulfoxides including DMSO and the corresponding activities were cross-induced, it suggest that a single enzyme of the DMSO-reductase family with a broad substrate specificity is responsible for various sulfoxide-dependent respiration in haloarchaea.

长期以来，人们一直知道二甲基亚砜（DMSO）在生活在高盐湖中的几种基本有氧的极其嗜盐的欧氏古菌中支持无氧呼吸。最近，还显示出它在基本上厌氧的硫还原卤代古细菌中被用作附加的电子受体。在这里，我们研究了卤古菌是否能够与其他两种亚砜（蛋氨酸亚砜（MSO）和四亚甲基亚砜（TMSO））进行厌氧呼吸。为此，在西伯利亚西南部和俄罗斯南部的高盐和苏打湖中沉积了厌氧菌。用酵母提取物获得了MSO和TMSO的正富集，但没有以甲酸或乙酸盐为电子供体。从盐湖中获得的两种纯培养物，分别是MSO或TMSO，尽管该属的类型菌株不能利用任何亚砜，但它们都可以被硫化的哈拉​​纳氏古菌（Halanaeroarchaeum sulfireducens）吸收。从苏打湖中分离出的两种纯净培养物是兼性厌氧的嗜盐卤古菌，使用O ₂，硫和亚砜作为电子受体。一个分离株与先前描述的减少硫的Natrarchaeobaculum sulphireducens相同，而另一个分离株以较低的碱度富集，正在形成Halobiforma属的新物种。。由于所有富含MSO或TMSO的分离物都能够释放包括DMSO在内的所有三种亚砜，并且交叉诱导了相应的活性，因此表明具有广泛底物特异性的DMSO还原酶家族的单一酶可导致多种亚砜盐生细菌中的依赖性呼吸。