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Proteus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Paola Scavone, Victoria Iribarnegaray, Pablo Zunino
On the other hand, Stankowska et al. [75] identified the luxS gene coding S-ribosylhomocysteine lyase responsible for AI-2 synthesis, proving that P. mirabilis uses a quorum-sensing communication system.
Antibacterial Activity of Seaweeds and their Extracts
Published in Leonel Pereira, Therapeutic and Nutritional Uses of Algae, 2018
Lactones are a chemical class of cyclic esters, which includes furanones. The Australian red seaweed Delisea pulchra has been studied for its ability to remain free of surface bacterial colonization. Halogenated furanone extracts from D. pulchra have been used as effective surface sanitizers in the prevention of Pseudomonas aeruginosa biofilm formation. This halogenated furanone also inhibits quorum sensing mechanisms by interfering with bacterial inter-cell communication. In order for bacteria to express specific genes during quorum sensing, signaling molecules called acyl-homoserine lactones (AHLs) are required, as well as luminescence transcriptional activator (LuxR) regulatory proteins. The furanone extract frompulchra competes with AHL for the LuxR receptor site, thereby inhibiting virulence factor production and pathogenesis in Pseudomonas aeruginosa (Hentzer and Givskov 2003, Brameyer and Heermann 2015). Ren et al. (2004) found a similar inhibition of quorum sensing in Escherichia coli with a (5Z)4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone extract from D. pulchra. Quorum sensing in Escherichia coli was inhibited by blocking S-ribosylhomocysteine lyase (LuxS) mediated AI-2 signaling. This influences genes and proteins involved in the normal production of flagellar synthesis, motility, and chemotaxis in the bacterium. Manefield et al. (2001) identified another mechanism of inhibition exerted by a halogenated furanone from D. pulchra. The bacterium, Erwinia carotovora, produces carbapenem as a virulence factor during quorum sensing. A commercially available 4-bromo-5-(bromomethylene)-3(1’-hydroxybutyl)-2(5H)-furanone was found to inhibit carbapenem production in Erwinia carotovora by disrupting the 3-oxo-C6-HSL dependent expression of the car ABCDEFG Hoperon. Castillo et al. (2015) also reported that a commercially produced furanone, similar to the D. pulchra extract, was effective against GramCampylobacter jejuni. When combined with epigallocatechin gallate from green tea and a citric acid extract, AI-2 activity, bacterial motility, and biofilm formation was significantly decreased.
Anti-biofilm activities of coumarin as quorum sensing inhibitor for Porphyromonas gingivalis
Published in Journal of Oral Microbiology, 2022
Zhiyan He, Wei Jiang, Yiting Jiang, Jiachen Dong, Zhongchen Song, Jianrong Xu, Wei Zhou
Biofilms are formed by microorganisms attached to a substratum and are composed of extracellular polysaccharides (EPS), proteins, lipids, and extracellular DNA [11]. Compared to planktonic bacteria, biofilm communities display specific properties such as being highly resistant to antimicrobial tolerance and better adapted to external environments [12]. Therefore, strategies focusing on eradicating the biofilm phenotype to avoid antimicrobial resistance have recently attracted much attention. Quorum sensing (QS) signals play an essential role in the biofilm development and dispersal [13]. QS is a well-known cell–cell communication system where bacteria produce and respond to signaling molecules known as autoinducers, sense the population density, and coordinate inter- and intra-population behaviour [14]. The bacterial autoinducers as signaling molecules in QS are autoinducer-1 (AI-1, acyl-homoserine lactones), autoinducing peptides (AIPs), and autoinducer-2 (AI-2, furanosyl borate diester) for cell-to-cell communications. Gram-negative bacteria employ acyl-homoserine lactones, whereas Gram-positive bacteria produce autoinducing peptides. Autoinducer-2, produced by the enzyme S-ribosylhomocysteine lyase (LuxS), is used for intra- and inter-species communication in both Gram-positive and Gram-negative bacteria [15–17]. As a new kind of potential antibiotic substitute, QS inhibitors have gained attention for inhibiting bacterial pathogenesis and not inducing antibiotic resistance. Hence, disrupting the QS process, including the application of quorum sensing inhibitors, is a critical way to control biofilm infections [18].
Promising treatment strategies to combat Staphylococcus aureus biofilm infections: an updated review
Published in Biofouling, 2020
P. S. Seethalakshmi, Riya Rajeev, George Seghal Kiran, Joseph Selvin
Quorum sensing system in S. aureus involves S- ribosylhomocysteine lyase (LuxS) and AI-2 which act together with agr-mediated quorum sensing system to regulate biofilm formation (Yu et al. 2012), but there is no strong evidence so far supporting the existence of AI-2 receptors (Ma et al. 2017). However, a study conducted by Zhao et al. (2010) proved that the LuxS/AI-2 system controls the synthesis of capsular polysaccharide, indicating that it can act as a complementary pathway to the whole quorum sensing mechanism in S. aureus.
LsrB, the hub of ABC transporters involved in the membrane damage mechanisms of heavy ion irradiation in Escherichia coli
Published in International Journal of Radiation Biology, 2021
Xin Li, Lei Chen, Haitao Zhou, Shaobin Gu, Ying Wu, Bing Wang, Miaomiao Zhang, Nan Ding, Jiaju Sun, Xinyue Pang, Dong Lu
LuxS encodes S-ribosylhomocysteine lyase and responses for the synthesis of AI-2 (Zuo et al. 2019). As an important member of the AI-2 QS system, LsrB interacts closely with the other seven lsr operon proteins in the AI-2 system and LuxS. Analyzed by cytoHubba, the nine nodes calculated by MCC have the same score, showing that the nine nodes interact with each other and have the same status. This means that nine members of the AI-2 system are involved in the mechanism of bacterial membrane damage by HI.