Inhibition of biofilm in Bacillus amyloliquefaciens Q-426 by diketopiperazines
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Biofilm formation can make significant effects on bacteria habits and biological functions. In this study, diketopiperazines (DKPs) produced by strain of Bacillus amyloliquefaciens Q-426 was found to inhibit biofilm formed in the gas–liquid interface. Four kinds of DKPs were extracted from B. amyloliquefaciens Q-426, and we found that 0.04 mg ml−1 DKPs could obviously inhibit the biofilm formation of the strain. DKPs produced by B. amyloliquefaciens Q-426 made a reduction on extracellular polymeric substance (EPS) components, polysaccharides, proteins, DNAs, etc. Real-time PCR was performed to determine that whether DKPs could make an obvious effect on the expression level for genes related to biofilm formation in the strain. The relative expression level of genes tasA, epsH, epsG and remB which related to proteins, extracellular matrix, and polysaccharides, were downregulated with 0.04 mg ml−1 DKPs, while the expression level of nuclease gene nuc was significantly upregulated. The quantitative results of the mRNA expression level for these genes concerted with the quantitative results on EPS levels. All of the experimental results ultimately indicated that DKPs could inhibit the biofilm formation of the strain B. amyloliquefaciens Q-426.
KeywordsBiofilm Diketopiperazines (DKPs) Extracellular polymeric substance (EPS) Real-time PCR Bacillus amyloliquefaciens Q-426
Extracellular polymeric substance
Atomic force microscope
This study was financially supported by Foundation of Key Laboratory of Marine Environmental Corrosion and Bio-fouling (MCKF201402), Institute of Oceanology, Chinese Academy of Sciences, One Hundred-Talent Plan of Chinese Academy of Sciences (CAS) and Research Program of CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation (No. 1189010002).
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