甲烷古菌群感效应信号分子的检测

Detection of the quorum sensing signals in methanogenic Archaea

摘要:

摘要: 竹节状甲烷鬃菌(Methanosaeta harundinacea) 6Ac 是本实验室分离自厌氧颗粒污泥中的甲烷古菌新种。该菌具有短杆(3μm－5μm)和长链状(＞200μm) 两种细胞形态，且与细胞密度相关，暗示该菌可能存在群感效应调控的细胞形态变化。【目的】验证该菌存在群感效应信号分子并与细胞形态变化相关。【方法】用高丝氨酸内酯指示菌Agrobacterium tumefaciens NTL4 检测菌株6Ac 的培养液，并用购买的高丝氨酸内酯标准品加入短杆菌株6Ac 检测形态变化。【结果】菌株6Ac 的培养液中含有高丝氨酸内酯类物质。实验证明化学合成的高丝氨酸内酯N-(β-酮基) 辛酰高丝氨酸内酯能够促进竹节状甲烷鬃菌的长链细胞形成。而且在马氏甲烷八叠球菌(Methanosarcina mazei) 、热自养甲烷杆菌(Methanothermobacter thermautotrophicus)和甲酸甲烷杆菌(Methanobacterium formicicum)的培养液中也检测到了高丝氨酸内酯。【结论】多种甲烷古菌可以产生高丝氨酸内酯类物质，并可能以此类物质作为群感效应的信号分子。

Abstract:

Abstract: Methanosaeta harundinacea 6Ac displayed a cell-density dependent cell morphology transition between short rods (3μm－5μm) and filaments (＞ 200μm) ，implying a quorum sensing system in this archaeon.[Objective］This study aimed to confirm that cell morphology related quorum sensing exists in Methanosaeta harundinacea.[Methods］By using the bioassay of Agrobacterium tumefaciens NTL4，we determined the presence of acyl homoserine lactones (AHLs) in the spent cultures of Methanosaeta harundinacea 6Ac and other three methanogens．A chemical synthetic AHL，N-(β-Ketooctanoyl) -L-homoserine lactone was added into the culture of short rods to detect the morphology change.[Results］We determined that AHLs were produced by Methanosaeta harundinacea，Methanosarcina mazei，Methanothermobacterthermautotrophicus and Methanobacterium formicicum． Addition of N-(β-Ketooctanoyl) -L-homoserine lactone into theculture of Methanosaeta harundinacea 6Ac stimulated the formation of filamentous cells．［Conclusion］This study indicates that AHL-based quorum sensing may be used by several species of methanogenic Archaea．