中文摘要：

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。

英文摘要：

Methanosaeta harundinacea 6Ac displayed a cell-density dependent cell morphology transition between short rods（3 μm-5 μm） 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,Methanothermobacter thermautotrophicus and Methanobacterium formicicum.Addition of N-（β-Ketooctanoyl）-L-homoserine lactone into the culture 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.