Priha O, Virkajärvi V, Juvonen R, Puupponen-Pimiä R, Nohynek L, Alakurtti S, Pirttimaa M, Storgårds E
VTT Technical Research Centre of Finland, P.O. Box 1000, 02044, Espoo, Finland,
Curr Microbiol. 2014 Nov;69(5):617-27. doi: 10.1007/s00284-014-0627-3. Epub 2014 Jun 19.
Bacteria use quorum sensing signalling in various functions, e.g. while forming biofilms, and inhibition of this signalling could be one way to control biofilm formation. The aim of this study was to evaluate the production of signalling molecules and its correlation with the biofilm formation capability of bacteria isolated from brewery filling process. A further aim was to study berry extracts and wood-derived terpenes for their possible quorum sensing inhibitory effects. Out of the twenty bacteria studied, five produced short-chain and five long-chain AHL (acyl homoserine lactone) signalling molecules when tested with the Chromobacterium violaceum CV026 reporter bacterium. Production of AI-2 (autoinducer-2) signalling molecules was detected from nine strains with the Vibrio harveyi BB170 bioassay. Over half of the strains produced biofilm in the microtitre plate assay, but the production of AHL and AI-2 signalling molecules and biofilm formation capability did not directly correlate with each other. Out of the 13 berry extracts and wood-derived terpenes screened, four compounds decreased AHL signalling without effect on growth. These were betulin, raspberry extract and two cloudberry extracts. The effect of these compounds on biofilm formation of the selected six bacterial strains varied. The phenolic extract of freeze-dried cloudberry fruit caused a statistically significant reduction of biofilm formation of Obesumbacterium proteus strain. Further experiments should aim at identifying the active compounds and revealing whether quorum sensing inhibition causes structural changes in the biofilms formed.
细菌在多种功能中使用群体感应信号传导，例如在形成生物膜时，抑制这种信号传导可能是控制生物膜形成的一种方法。本研究的目的是评估从啤酒厂灌装过程中分离出的细菌信号分子的产生及其与生物膜形成能力的相关性。另一个目的是研究浆果提取物和木材衍生的萜类化合物对群体感应的可能抑制作用。在所研究的20种细菌中，用紫色色杆菌CV026报告菌测试时，有5种产生短链AHL（酰基高丝氨酸内酯）信号分子，5种产生长链AHL信号分子。用哈维氏弧菌BB170生物测定法从9个菌株中检测到AI-2（自诱导物-2）信号分子的产生。超过一半的菌株在微量滴定板试验中产生生物膜，但AHL和AI-2信号分子的产生与生物膜形成能力之间没有直接相关性。在筛选的13种浆果提取物和木材衍生的萜类化合物中，有4种化合物降低了AHL信号传导而对生长没有影响。这些化合物是桦木醇、树莓提取物和两种云莓提取物。这些化合物对所选6种细菌菌株生物膜形成的影响各不相同。冻干云莓果实的酚类提取物使变形杆菌菌株的生物膜形成在统计学上显著减少。进一步的实验应旨在鉴定活性化合物，并揭示群体感应抑制是否会导致所形成生物膜的结构变化。
