副干酪乳杆菌HD1.7群体感应行为

Quorum-sensing behavior of Lactobacillus paracasei HD1. 7

摘要:

摘要:【目的】Paracin1.7是从副干酪乳杆菌(Lactobacillus paracasei)HD1.7 发酵液中提取的一种细菌素，本文主要研究菌株HD1. 7 在发酵过程中调控Paracin1.7代谢的群体感应机制。【方法】利用杯碟法检测不同生长条件下菌株HD1. 7 培养液的抑菌活性，通过调整培养基营养成分的多寡，控制培养液中细胞密度。【结果】菌株HD1. 7 的抑菌活性与其细胞密度密切相关，只有当细胞密度达到一定的阈值(OD600为0.8，菌体干重为0.3311g/L)时，菌株才能表现抑菌活性

Abstract:

Abstract:［Objective］ Paracin 1.7 was a bacteriocin extracted from Lactobacillus paracasei HD1.7．In this study，we investigated quorum-sensing mechanism that regulates the metabolism of Paracin 1.7 in strain HD1.7．［Methods］ The antibacterial activity of strain HD1. 7 under different growth conditions was analyzed using an agar-well diffusion method，and the cell density was controlled by adjusting nutrient levels in the culture medium． ［Results］The antibacterial activity of strain HD1. 7 depended on cell density．Strain HD1.7 exhibited the antibacterial activity when the cell density reached a threshold (OD600 of 0.8 and cell dried weight of 0. 3311g/L)．Addition of different concentrations of a signaling molecule in the supernatant of the fermentation broth affected the antibacterial activity． After removing the signal molecule，the antibacterial activity was significantly decreased．［Conclusion］ Paracin1. 7 was the quorum-sensing signaling molecule in the HD1.7 fermentation broth and it could be auto-induced．The antibacterial activity of Paracin1.7 was regulated by the quorum-sensing system in HD1.7．