Food-borne pathogens pose great risks to human health and public safety, and the formation of biofilm exacerbates their pathogenicity and antimicrobial resistance. Enzymes can target special substances in the biofilm to disintegrate the biofilm of food-borne pathogens, which has great potential for applications. This review summarized the progress of using enzymes to disintegrate the biofilms of food-borne pathogens, highlighting quorum-quenching enzymes, C-di-GMP metabolic enzymes, as well as extracellular matrix hydrolases. Finally, challenges and perspectives on developing enzymes into effective products for disintegrating the biofilms of food-borne pathogens were discussed.
Biofilms ; Humans ; Quorum Sensing

No Abstract Available.
Quorum Sensing* ; Vibrio vulnificus* ; Vibrio* ; Virulence*

No Abstract Available.
Quorum Sensing* ; Vibrio vulnificus* ; Vibrio* ; Virulence*

OBJECTIVETo study the influence of the quorum sensing inhibitor brominated furanone on Porphyromonas gingivalis (P. gingivalis) biofilm formation.

METHODSDoubling dilution method was used to determine the minimal inhibition concentration (MIC) of brominated furanone on P. gingivalis. Absolute ethyl alcohol added in P. gingivalis bacterial suspension was used as the negative control, while P. gingivalis bacterial suspension as blank control. The influences of 1/4MIC, 1/2MIC, MIC, 2MIC of brominated furanone on P. gingivalis biofilm formation were studied by the optical density determination and scanning electron microscope (SEM).

RESULTSFour groups of brominated furanone with different concentrations were shown to inhibit P. gingivalis biofilm formation. With the increased concentration of brominated furanone, optical density of P. gingivalis suspension decreased. The biofilm structures of 1/4MIC group, 1/2MIC group and MIC group were loose. Only scattered P. gingivalis cells but no biofilm structure was seen in 2MIC group.

CONCLUSIONBrominated furanone could inhibit P. gingivalis biofilm formation without the influence on bacterial growth. The future application of this chemical compound may provide a new possibility for the antimicrobial treatment of periodontal disease.

Bacteria ; cytology ; metabolism ; Quorum Sensing ; Signal Transduction

BACKGROUND AND OBJECTIVE: Many opportunistic and nosocomial pathogens like Pseudomonas aeruginosa are very reliant on a bacterium-to-bacterium communication system called quorum sensing (QS). Without the aforementioned process, gene expressions associated with virulence factors will not be produced. In this study, the sub-inhibitory concentrations (sub-MICs) of methanolic leaf extract and obtained fractions from Averrhoa bilimbi (kamias) were screened for ability to inhibit quorum sensing-controlled phenotypes of P. aeruginosa ATCC 27853. METHODOLOGY: A. bilimbi crude extract was fractionated through liquid-liquid extraction, producing four (4) fractions: hexane fraction, dichloromethane (DCM) fraction, ethyl acetate (EtOAc) fraction, and water (H2O) fraction. Among the sub-MICs obtained from resazurin-based fluorimetric microtiter assay, only 50 μg/mL was utilized in evaluating the anti-QS properties of crude extract and fr RESULTS: In the swarming motility assay, hexane fraction (9.39 mm ± 0.67) and DCM fraction (10.82 mm ± 0.95) displayed restriction in the treated P. aeruginosa ATCC 27853 swarms against the control (16.20 mm ± 2.55). In the anti-pyocyanin production assay, hexane fraction exhibited an inhibition of 42.66 % ± 12.94. TLC analysis and phytochemical screening revealed that hexane fraction contains steroids, terpenes, triterpenes, and glycolipids; and DCM fraction contains cardiac glycosides, triterpenoids, terpenes, triterpenes, steroids, alkaloids, and glycolipids. CONCLUSION Hexane and DCM fractions obtained from A. bilimbi significantly inhibited swarming of P. aeruginosa ATCC 27853 while none of the extracts were able to significantly inhibit pyocyanin formation of P. aeruginosa ATCC 27853.
Pseudomonas aeruginosa ; Averrhoa bilimbi ; quorum sensing ; pyocyanin

Vibrio vulnificus, a gram-negative halophilic marine bacterium and opportunistic pathogen, must withstand various environmental changes, especially the simultaneous change of temperature and salinity (SCTS) from 25degrees C/2.5% to 37degrees C/0.9% upon entering the human body. Previous studies have suggested that temperature and salinity may affect the production of metalloprotease VvpE via the LuxS-mediated autoinducer-2 quorum sensing system (AI-2-QSS). However, this hypothesis remains to be verified through coherent experiments. In this study, SCTS stimulated V. vulnificus growth with no increase in total growth levels. The SCTS-mediated prolongation of the stationary growth phase resulted in a significant increase in growth phase-dependent luxS and vvpE transcriptions; however, SCTS did not affect luxS or vvpE transcription levels during the exponential growth phase. SCTS also advanced extracellular VvpE production, which was consistent with vvpE transcription and V. vulnificus growth. SCTS-mediated modulation of vvpE expression was slightly attenuated but still observed in the background of a luxS mutation which seriously repressed vvpE expression. These results indicate that SCTS stimulates luxS and vvpE expression by stimulating V. vulnificus growth; however, the LuxS-mediated AI-2-QSS plays only a minor role, if any, in the SCTS-mediated modulation of vvpE expression.
Human Body ; Quorum Sensing ; Salinity ; Vibrio ; Vibrio vulnificus

The exogenous gene expression and its impacts on the bacterial population are important to study quorum sensing systems and synthetic biology industry. However, the behavior of exogenous protein expressing bacteria remains poorly understood. To find out which factors are playing a critical role in the growth of population and exogenous gene expression, we measured Lux-type receptor-regulated exogenous gene expression under the induction of N-acyl homoserine lactone (N-AHL) signaling molecules and impacts on the bacterial population dynamics after such stimulation. To analyze the cause of fitness burden of bacteria, we set up a hypothetical mathematical model. Previous studies often arrogate this phenomenon to the synthesis cost and the toxicity of N-AHL signaling molecule. However, we suggested another possible cause of the fitness burden.
Bacteria ; Gene Expression ; Gene Expression Regulation, Bacterial ; Quorum Sensing

Quorum sensing (QS) is a cell density-dependent communication mechanism between bacteria through small signaling molecules. When the number of QS signaling molecules reaches a threshold, they are transported back into the cells or recognized by membrane-bound receptors, triggering gene expression which affects various phenotypes including bioluminescence, virulence, adhesion, and biofilm formation. These phenotypes are beneficial for bacterial survival in harsh environments. This review summarizes the application of QS inhibitors for control of biofilm formation and virulence expression of periodontal pathogens.
Bacteria ; Biofilms ; Gene Expression ; Periodontitis ; Phenotype ; Quorum Sensing ; Virulence

Quorum sensing (QS) plays a major role in the outbreak mechanism of foodborne diseases caused by food poisoning and food spoilage. QS affects the formation of cell membrane and pathogenicity ofpathogenic bacteria. Through the in-depth understanding of QS molecules of food-borne pathogens, we describe here the types of signal molecules produced by Gram-negative and Gram-positive bacteria, and the differences in QS molecules. Meanwhile, we introduce the detection of QS molecules by different technologies. According to the influence of QS on food, we propose also future research needs for the control of foodborne pathogenic bacteria.
Gram-Negative Bacteria ; Gram-Positive Bacteria ; Quorum Sensing