The importance of hydrogen and formate transfer for syntrophic fatty, aromatic and alicyclic metabolism.
The importance of hydrogen and formate transfer for syntrophic fatty, aromatic and alicyclic metabolism.
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DOI：
10.1111/1462-2920.12269
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发表时间：
2014
影响因子：
5.1
通讯作者：
J. Sieber;H. Le;M. McInerney
中科院分区：
文献类型：
--
作者：
J. Sieber;H. Le;M. McInerney
我们采用基因组学、转录学和酶学分析相结合的方法来确定两种模式共生微生物——狼胞合单胞菌和嗜酸营养菌合单胞菌的种间电子转移机制。这两种生物都含有多种氢化酶和甲酸脱氢酶基因，但缺乏外膜细胞色素和纳米线形成的基因。嗜酸嗜养葡萄球菌和狼耳葡萄球菌共养培养细胞和无细胞提取物均具有氢化酶和甲酸脱氢酶活性。氢化酶抑制剂（氰化物和一氧化碳）可抑制wolfei s和hungatei Methanospirillum洗涤细胞悬浮液的丁酸盐代谢和CH4产生，而甲酸脱氢酶抑制剂（次磷酸酯）则不能。次亚磷酸抑制了嗜酸嗜养链球菌和亨盖特芽胞杆菌胞悬液的合养苯甲酸酯氧化和CH4生成，而氰化物和一氧化碳则没有抑制作用。所有三种抑制剂都停止了合营养环己烷-1-羧酸代谢。两种氢化酶基因hydA1和hydA2在狼孢菌共养生长时表达量更高。S. aciditrophicus在合养苯甲酸盐和环己烷-1-羧酸盐生长过程中表达了多个氢化酶和甲酸脱氢酶基因，其中fdhA2在合养苯甲酸盐生长过程中高度差异表达。因此，这些共生微生物具有灵活的代谢，允许它们根据所涉及的底物使用H2或甲酸转移。
We used a combination of genomic, transcriptional and enzymatic analyses to determine the mechanism of interspecies electron transfer by two model syntrophic microorganisms, Syntrophomonas wolfei and Syntrophus aciditrophicus. Both organisms contain multiple hydrogenase and formate dehydrogenase genes, but lack genes for outer membrane cytochromes and nanowire formation. Syntrophically grown cells and cell-free extracts of S. aciditrophicus and S. wolfei had both hydrogenase and formate dehydrogenase activities. Butyrate metabolism and CH4 production by washed cell suspensions of S. wolfei and Methanospirillum hungatei were inhibited by hydrogenase inhibitors (cyanide and carbon monoxide), but not by a formate dehydrogenase inhibitor (hypophosphite). Syntrophic benzoate oxidation and CH4 production by washed cell suspensions of S. aciditrophicus and M. hungatei were inhibited by hypophosphite, but not cyanide and carbon monoxide. All three inhibitors halted syntrophic cyclohexane-1-carboxylate metabolism. Two hydrogenase genes, hydA1 and hydA2, were more highly expressed when S. wolfei was grown syntrophically. S. aciditrophicus expressed multiple hydrogenase and formate dehydrogenase genes during syntrophic benzoate and cyclohexane-1-carboxylate growth, one of which (fdhA2) was highly differentially expressed during syntrophic benzoate growth. Thus, these syntrophic microorganisms have flexible metabolisms that allow them to use either H2 or formate transfer depending on the substrate involved.