A case study on chemical defense based on quorum sensing: antibacterial activity of sponge-associated bacterium Pseudoalteromonas sp NJ6-3-1 induced by quorum sensing mechanisms

作者：Guo, Xiuchun; Zheng, Li^*; Zhou, Wenhui; Cui, Zhisong; Han, Ping; Tian, Li; Wang, Xiaoru

来源：Annals of Microbiology, 2011, 61(2): 247-255.

DOI：10.1007/s13213-010-0129-x

• Quorum sensing
• Sponge-associated bacterium
• Antibacterial activity
• Diketoperazines

A case study to investigate the relationship between antibacterial activity and quorum sensing mechanisms was carried out on a sponge-associated bacterium with remarkable biological activities: Pseudoalteromonas sp. NJ6-3-1. The dependence of active substance production on cell density was studied under various growth conditions. Bacteria NJ6-3-1 was found to start producing antibacterial compounds only when cell density reached the threshold value of OD(630) = 0.4. To simulate the competitive real marine environment, NJ6-3-1 at low cell density (OD(630) value below the required threshold value) was co-cultured with the terrestrial bacterium Staphylococcus aureus. Antibacterial activity assays indicated the existence of some signal molecules in the metabolites of S. aureus that could induce NJ6-3-1 to produce antibacterial substances even at low cell density. Three diketopiperazines (DKPs) as metabolites and potential autoinducers of NJ6-3-1 were synthesized and co-cultured with low density NJ6-3-1. The antibacterial activity assay showed that one of these DKPs-cyclo-(l-Phe-l-Val)-was the autoinducer and could indeed induce NJ6-3-1 to produce antibacterial substances under low cell density. Our results thus provide preliminary support to the hypothesis that the antibacterial activity of NJ6-3-1 is controlled by the quorum sensing system in both an intra-species and an inter-species manner.

• 出版日期2011-6
• 单位中国海洋大学; 国家海洋局第一海洋研究所